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GICHUKI MRMUCHIRI. "Gichuki Muchiri. 2004. Conservation tillage Equipment productivity quantified. A case study in semiarid smallholder Agriculture in Eastern Kenya. Unpublished PhD Thesis submitted for examination. University of Nairobi.". In: Oral presentation, AFRA IV (RAF/4/009) Regional Meeting on Current and Future Activities in Maintenance and Repair of Nuclear Instruments. Arusha, Tanzania: 28th February to 2nd March 1994. University of Nairobi.; 2004.
Gichuki N. Law of Financial Institutions in Kenya. Nairobi: LawAfrica; 2011.
Gichuki FN;, Mungai DN;, Gachene CKK. Soil erosion and conservation activities on land affected by road drainage: a case study of Nyeri District..; 2000. AbstractWebsite

The existing soil erosion damage caused by water drained from minor roads in the Nyeri District of Kenya was assessed and the soil conservation works needed to stabilize the waterways and gullies along the roads are specified. The study evaluated the land affected by road drains/culverts on 25 minor roads with a total length of 149 km. Of the total of 321 culverts identified, 171 (53%) were found to require channel rehabilitation. 68% of the culverts discharged onto steep slopes (>10%). Erosion was found to be more severe in the coffee-growing zones than in tea-growing areas. In the plateau areas, soil erosion from the culvert outlets was minimal. Due to gentle slopes and more perennial vegetation. 20,346 m of channel excavation was needed to provide artificial waterways for the discharge of water drained from the roads. Channel stabilization with grass cover or installation of scour checks was necessary on very gentle slopes. Steep slopes required stone check-dams and single-row post/stone check-dams. Very steep slopes also required lock-and-spill drains and post/stone/wire check-dams. Gabions (57 crossings) were needed mainly for rehabilitation of large gullies along with double-row post/stone check-dams and post/stone/wire check dams. Cut-off drains were necessary in some cases to divert water from the culvert outlets. In areas where vegetation was easily accessible, brushwood check-dams could be used.

Gichuki FN;, Mungai DN;, Thomas DB. Development of a streamflow model for rural catchments in Kenya..; 1993. AbstractWebsite

A stream flow model was developed for use in rural catchments in Kenya. In the model the physical environment was divided into three zones: the unsaturated zone (consists of multiple hydrological response units defined by homogenous land use and soil type in which a daily soil moisture balance is maintained), shallow saturated and deep saturated zones which were modelled as regional aquifers. Rainfall and evapotranspiration were distributed according to altitude, and runoff was determined using the curve number method devised by the US Soil Conservation Service: a function of five-day antecedent precipitation. Evapotranspiration was varied according to the soil moisture content, and the weather generator allowed Monte Carol simulations over a long period. The data consisted of daily rainfall, mean daily evaporation for each month, land use/vegetation and soil type. The ARC-INFO GIS package was used to assemble the topographical, hydrological, land use/vegetation type and soil information in different layer. The model was tested on the Naro Moru catchment (172kn2) in Kenya, which has climatic conditions that vary from the glaciated peaks of Mount Kenya (5,200 m) to the semi-arid Laikipia plateau (1,800 m). The model was calibrated over a two-year period and validated over a different two-year period. A comparison of the observed and simulated stream flow showed that minimal calibration was required. The simulated stream flow compared well with the observed values for both the calibration and the validation periods (70-85% for the 10-day period) indicating that the model is appropriate for ungauged catchments.

Gichuki FN;, Mungai DN;. Hedgerows for control of soil erosion in Kabale, southwest Uganda..; 2000. AbstractWebsite

Runoff and soil loss was studied on steep terraced slopes containing various combinations of lines of Grevillea robusta, hedgerows of Calliandra calothyrsus and strips of Pennisetum purpureum in Kabale, southwest Uganda. A factorial design, replicated three times, included three levels of intra-row spacing (0, 3 and 5m) of Grevillea spp. and three understorey types (none, Pennisetum and Calliandra spp). The understorey and Grevillea were interplanted along a contour in the middle of the terrace parallel to the two adjacent risers. Results indicate that when contour lines of trees are on fallow ground there is little or possibly a negative effect in controlling soil and water loss. When contour lines are on steep cultivated terraces they have a significant effect in reducing losses. The understoreys appear to filter out much of the sediment from the runoff, holding it in or above the contour line of the vegetation. The potential for using contour lines of Pennisetum and Calliandra for controlling soil and water loss is discussed.

Gichuki FN;, Gachene CKK, Mungai DN;. Minimizing hydrological impacts of smallholder drainage development.; 2000. AbstractWebsite

A review of available literature on the hydrologic impacts of drainage is presented and management practices that reduce such impacts are identified. Factors that influence the impact of drainage include land use, soil type, drainage density, type and condition of the drains, size and duration of the storm, and extent and location of the drainage. Suggested options for minimising impacts include: appropriate land use (fish ponds, duck farming, harvesting natural products, dry season grazing or cultivation); controlled drainage through use of shallow drains, drainage for growing water-loving plants, land preparation (hilling, cambered beds), and blocking drains at the end of the rains; and water storage (dams along the river or farm ponds).

Gichuki, FN; Mungai DN;, Gachene CKK, Gichuki FN;. A participatory route towards conservation farming for better land husbandry..; 2000.Website
Gichuki FN;, Mungai DN;, Gachene CKK. Soil and water management in semi-arid Kenya: an overview..; 2000. AbstractWebsite

This paper presents results of a study aimed at quantifying soil and water management practices and identifying major constraints and implications for future adoption of appropriate technologies. The study was conducted in the Machakos and Makueni Districts of Kenya. Approximately 83% of the farmers interviewed were using manure, while only 4% use fertilizer. 60% had fanya juu terraces on their land, while only 13% were using grass strips. The study concluded that finance is a major constraint limiting farmers' adoption of practices enhancing soil fertility and that lack of conservation practices on grazing land is of great concern. The lack of knowledge of possible benefits of soil and water management practices is noted.

Gichuki FN, Gachene CKK. Biological and water-harvesting measures for gully control.; 2000. AbstractWebsite

The Arpolo gullying control project in the West Pokot Region of Kenya is described. This is an example of conservation work done to protect the Arpolo dispensary which cost >KES350,000 to put up and serves about 3,000 people and is threatened by a fast-growing gully. The initial proposal for a concrete wall in the first phase of implementation was not feasible since it would be undermined during the rains. The alternative was to plan, design and apply water-harvesting methods and implement biological measures that would reduce the erosive energy of the surface runoff. The design of the water-harvesting structures is shown. The success of the project shows that land and water management requires skillful planning and design, especially where soils are vulnerable to erosion. The physical and chemical properties of the soils in the area are described. Given proper hydraulic designs, water-harvesting measures are still a reliable means of soil conservation.

Gichuki NN, Ndiwa T, Jackson C, Olivier H. "Status of globally threatened waterbirds in Tana delta, Kenya.". In: Third Biennial Scientific Conference, National Musuems of Kenya, Nairobi. Nairobi, Kenya ; 2011.
Gichuki NN, Oyieke HA, Ndiritu GG, Handa C. Wetland biodiversity in Kajiado District.; 1998.
Gichuki ML, Ogollah K. "FACTORS INFLUENCING THE CHOICE OF MARKETING STRATEGIES OF COMMERCIAL BANKS IN KENYA ." The strategic Business and change Journal of Management. 2014;2(24):450-474.gichuki_lucy_and_ogollah_2014.pdf
Gichuki FN;, Mungai DN;, Gachene CKK;, Thomas DB. "Land and water management in Kenya: towards sustainable land use.".; 2000. Abstract

Preliminary findings on the effects of land use in the Masinga Dam catchment, Kenya, on the storage capacity of the reservoir are presented. Remote sensing and GIS techniques, supplemented with ground reports, were used to determine areas most susceptible to erosion. A representative catchment was then chosen for rainy season monitoring of soil loss, river suspended sediments and discharge response to rainfall. In addition, Gerlach-type traps were used to evaluate erosion rates under different crop covers and slope gradients. A sample of 200 households was interviewed about their perceptions of erosion problems on their farms. Preliminary results suggest that the major sediment-contributing areas are the densely populated and intensively cultivated foothills of the Aberdares, rather than the semi-arid lowlands directly bordering the reservoir. Poorly drained sealed and murram roads, together with footpaths, cattle tracks and gullies, act as extensions of the drainage network during storms, channelling sediment-laden runoff from bare areas around homesteads and schools directly into the river. Subsistence crops, particularly mono-cropped maize, appear to provide poor cover for a major part of the wet season.

http://www.cde.unibe.ch/Pages/Pub Gichuki, Francis N; Liniger H; MML; SG; GURI:G. "Scarce water: Exploring resource availability, use and improved management.". 1998.
Gichuki NN, Matagi S. "South Eastern Rift Valley Lakes of Eastern Africa.". In: Freshwater Ecosregions of Africa and Madagascar. New York: Island Press; 2005.
Gichuki N. Computer Contracts in Kenya: Proposals for Regulatory Reform. Nairobi: University of Nairobi; 1997.
Gichuki FN;, Mungai DN;, Thomas DB. Environmental and land-use consequences of sand harvesting in Masinga division..; 2000. AbstractWebsite

This paper examines the impact of sand harvesting from rivers on the environment, land use and social life in the Masinga Division, Machakos District, Kenya. Sand acts as a safe aquifer for water flowing below and through it. Removal of sand results in destruction of underground aquifers and loss of safe water. sand scooping adversely affects surface water quality and quantity and damages the aquatic ecosystem. Haulage of sand by heavy trucks causes environmental degradation by accelerating soil erosion and affecting soil stability. Storage of sand causes destruction of surface areas through clearing of vegetation and uses land that could be used for agriculture. Related social and health problems include prostitution and high school drop-out rate leading to serious social and health problems. The beneficial effects of sand harvesting include local employment; however, the share of monetary benefits to locals is minimal. The results show that the local community gains the least from sand harvesting, but stands to suffer the most if the degradation of the river system continues. Suggestions are made for safe and sustainable methods of managing sand harvesting, in which greater local involvement and stricter enforcement of regulations to protect the environment are vital.

GICHUKI MRMUCHIRI. "Gichuki Muchiri. 1985. Chapter three of the book: Farm equipment Deveiopment for Small Holders in Semiarid Areas of Southeastern and Central Africa. Edited by Iftikhar Ahmed and Bill Kinsey. Gower Publishers.". In: Oral presentation, AFRA IV (RAF/4/009) Regional Meeting on Current and Future Activities in Maintenance and Repair of Nuclear Instruments. Arusha, Tanzania: 28th February to 2nd March 1994. University of Nairobi.; 1985.
Gichuki FN;, Mungai DN;, Gachene CKK;, Thomas DB. Riverbank protection and food security..; 2000. AbstractWebsite

This paper reflects on the role of root crops (cocoyam, Colocasia esculenta or C. antiquorum) as a case study in riverbank protection and food security in Kenya. Field performance, water erosion control, ecologically friendly production and food value were studied. It is concluded that the national relevance of cocoyam cultivation lies in its role in its conservation through erosion control and soil fertility maintenance; its low energy input; its potential to supplement per capita calories through high yield per unit area; its perpetuity; its multiple nutritive value, ease of preparation and digestibility; and its industrial potential and competitive market opportunity for various end-products.

Gichuki FN;, Mungai DN;, Gachene CKK. Some" near-farmer" research on land and water management for crop production in semi-arid Kenya..; 2000. AbstractWebsite

This paper describes a "near-farmer" applied research project working on 10 field stations scattered through the arid and semi-arid lands of Embu, Meru and Isiolo Districts of Esatern Province, Kenya. The objective of the research was to define better extension messages for resource-poor farmers to enable them to improve their land and water management techniques for improved and sustained yields. Most of the trials related to soil fertility and soil moisture, as well as trials on the use of Vetiver grass for soil conservation, control of the legume root parasite Alectra vogelii, and new introductions such as groundnuts, simsim (sesame), tubers, fodder crops and fruits.

Gichuki FN;, Mungai DN;. The effect of varying rates of compost and diammonium phosphate on soil physical properties and crop performance..; 2000. AbstractWebsite

Long-term use of compost (4, 8, 12 or 125 kg/ha for maize and 10, 20, 30 or 200 kg/ha for beans) on improving crop yields and soil physical characteristics was studied at the steep-land research site, Kabete campus, Kenya. Preliminary results showed that maize yields under compost were lower than under diammonium phosphate (DAP). Compost increased the maize yield by 15% compared to an increase of 50% caused by DAP. Bean yield did not show any response to any rates of compost or DAP. The use of compost improved soil physical conditions, mainly bulk density and infiltration rates.

Gichuki FN;, Mungai DN;. Biological and water-harvesting measures for gully control.; 2000. AbstractWebsite

The Arpolo gullying control project in the West Pokot Region of Kenya is described. This is an example of conservation work done to protect the Arpolo dispensary which cost >KES350,000 to put up and serves about 3,000 people and is threatened by a fast-growing gully. The initial proposal for a concrete wall in the first phase of implementation was not feasible since it would be undermined during the rains. The alternative was to plan, design and apply water-harvesting methods and implement biological measures that would reduce the erosive energy of the surface runoff. The design of the water-harvesting structures is shown. The success of the project shows that land and water management requires skillful planning and design, especially where soils are vulnerable to erosion. The physical and chemical properties of the soils in the area are described. Given proper hydraulic designs, water-harvesting measures are still a reliable means of soil conservation.

Gichuki FN. "Makueni district profile: soil management and conservation, 1989-1998.". 2000. AbstractWebsite

The investments in soil conservation made by farmers in Makueni District, Kenya over the period 1950-1998, and the policy and institutional framework under which the investments were made are explored. An assessment of the scale and impact of these measures is presented. In general, very few signs of erosion were observed, so the area is considered to have low erosion status. Soil and water conservation measures include the use of crop residues in trash lines, contour ridging, grass strips, fanya juu terraces and cut-off drains. Crop residue management and tillage are the main practices used to facilitate in situ moisture conservation. Most farmers practise contour ridging. Physical soil conservation measures are used to complement cultural practices that conserve rainwater in situ by trapping and preventing further runoff. A key constraint to the expansion of soil and water conservation measures by households is the shortage of hired and family labour. Grazing land has received very little investment because there farmers perceive a low return. In Makueni District farmers have been able to make long-term investments in soil conservation partly because their land tenure was secure. Training and extension in soil and water conservation has been a major external input.

GICHUKI MRMUCHIRI. "Ministry of Agriculture. 1994. National Agricultural Mechanisation Strategy Formulation for Kenya. Project Coordinator and author of the summary document.". In: Oral presentation, AFRA IV (RAF/4/009) Regional Meeting on Current and Future Activities in Maintenance and Repair of Nuclear Instruments. Arusha, Tanzania: 28th February to 2nd March 1994. University of Nairobi.; 1994.
Gichuki N. "Financing Innovations: Enabling Intellectual Property (IP) to Steer National Development.". In: 2nd National Conference on Dissemination of Research Results and Exhibition of Innovations. Nairobi; 2009.
Gichuki FN;, Mungai DN;, Gachene CKK. Residual effect of lucerne on wheat yield: report of a farm trial at Njoro, Nakuru district..; 2000. AbstractWebsite

This paper presents results from a trial in Swara Farm, Njoro, Kenya, in which a field was sown with Sorghum almum on a volcanic ash soil. Immediately after sowing, 14 strips measuring 156 m x 9 m were marked out and alternate strips were oversown with inoculated seed of lucerne cv. Hairy Peruvian. During the first year of the trial no differences were noticed in the growth of S. almum, but during the second year it grew better when associated with lucerne. After two years the field was ploughed and sown with wheat. The strips were harvested separately with a combine harvester. Mean yields after S. almum were 2,708 kg/ha and after the S.almum/lucerne mixture were 3,244 kg/ha

Gichuki FN;, Mungai DN;, Gachene CKK. The range management handbook of Kenya: a database for planning development in arid and semi-arid areas of Kenya..; 2000. AbstractWebsite

This paper briefly presents a methodology for planning development in arid and semi-arid areas. It highlights the issues of problem identification and assessment of the natural and socio-economic environment, and describes the database contained in the Range Management Handbook. The handbook makes available baseline data for planning development in arid and semi-arid areas following a successful Farm Management Handbook that covers the high- and medium-potential areas of Kenya. In three parts, the Range Management Handbook covers: the status, principles and applications in Kenya; texts and maps relating to climate, landforms and soils, vegetation types, water sources, range unit inventory, livestock marketing and human ecology; special reports (guide to tolerant plants, pictorial key for goat stocking rates, large scale remote monitoring of vegetation, and a survey method for classification of range conditions) relevant to land planning and use in arid and semi-arid areas

Gichuki FN;, Mungai DN;. The impact of climatic changes on land and water resource management in Kenya..; 2000. AbstractWebsite

The implications of global climatic change on water resource development and management in Kenya was examined. The extent to which the water resources of the various regions of Kenya will be affected and the effects on streamflow regimes, rainfall amount, frequency and distribution patterns and the overall effects of these on socio-economic development are discussed. It is suggested that increased drought could occur in low-potential regions of Eastern, Rift valley and North Eastern Provinces, whilst regions that already receive a favourable amount of rainfall could have even higher amounts. Changes in rainfall patterns and stream discharge may require translocation of current water development projects with possible high costs and dire consequences for those dependent upon such projects. The increases aridity in the arid and semi-arid lands may lead to increased salinity of groundwater, limiting it's use. Recommendations include water conservation strategies, groundwater basin recharge, inter-basin water transfer from high to low potential zones, cloud seeding above arid and semi-arid areas, better soil and water conservation strategies, and controlling the use of products contributing to global warming.

Gichuki FN;, Mungai DN;, Gachene CKK. New ways of water development for pastoral areas: experiences from southern Marsabit district..; 2000. AbstractWebsite

During the last 40 years, water development in the southern Marsabit District of Kenya concentrated mainly on drilling boreholes and constructing large dams and pans which are difficult to maintain without financial aid. In order to make the nomads independent of outside aid, the Marsabit Development Programme has introduced animal traction for dam and pan construction and promotes the management of shallow wells. This paper reports the experiences encountered so far in the integration of water development within the natural resource improvement programme and discusses lessons learnt during the 1991/2 drought in the area in terms of water development and nomadic lifestyle.

Gichuki FN;, Gachene CKK, Mungai DN;. Peoples' participation in agroforestry: the case of the Pokot..; 2000.Website
Gichuki N. Law of Financial Institutions in Kenya (2nd edition). Nairobi: LawAfrica; 2013.
Gichuki FN;, Mungai DN;, Gachene CKK. Soil and water management in semi-arid Kenya: an overview..; 2000. AbstractWebsite

This paper presents results of a study aimed at quantifying soil and water management practices and identifying major constraints and implications for future adoption of appropriate technologies. The study was conducted in the Machakos and Makueni Districts of Kenya. Approximately 83% of the farmers interviewed were using manure, while only 4% use fertilizer. 60% had fanya juu terraces on their land, while only 13% were using grass strips. The study concluded that finance is a major constraint limiting farmers' adoption of practices enhancing soil fertility and that lack of conservation practices on grazing land is of great concern. The lack of knowledge of possible benefits of soil and water management practices is noted.

Gichuki NN, Dennis AU. "Challenges and possibilities of developing ecologically conscious technologies in Africa ." Hekima Review. 2013;(46):148-157.
Gichuki FN;, Mungai DN;, Gachene CKK;, Thomas DB. Use of soil survey information in soil and water management..; 2000. AbstractWebsite

The results of soil surveys at the ICIPE research site at Ungoye, South Nyanza, and the Ngori Ngori toposequence in Narok, Kenya, are discussed to provide insight into the applicability of soil survey information to soil and water management. It is concluded that soil survey information in soil and water management programmes can be used through understanding and appreciation of the criteria used in categorizing soils and their management implications. From the examples given it is noted that chemical aspects of the soil should be viewed not just as a means to assess its fertility, but also as a base to predict the behaviour of the soils when subjected to different types of management.

Gichuki FN;, Mungai DN;. An evaluation of gully control measures in Central Province, Kenya..; 2000. AbstractWebsite

Forty controlled gullies distributed in Kiambu, Murang'a and Nyeri Districts of Central Province, Kenya, were randomly selected to evaluate their control measures. A recording schedule was developed to assist in collecting pertinent information. Results indicate that the failure of gully control in Central Province can be attributed to lack of technically skilled personnel and poor maintenance of gully control structures. It is concluded that there is a great need to impart technical knowledge to technical staff, and that it is essential to intensify research on gully control techniques and that there is regular and proper maintenance of all gully control structures after rainstorms.

Gichuki NN, Macharia JM. "Participation of Local Communities in the Management of Wetlands in Magadi Area, Kenya.". 2003. AbstractParticipation of Local Communities in the Management of Wetlands in Magadi Area, Kenya

Wetlands are lands that are transitional between terrestrial and aquatic systems where the water is usually at or near the surface of the land or land that is covered with shallow water (Cowardin et al. 1979, Roggeri 1995). In the context of dry lands, wetlands are areas that are permanently, seasonally or occasionally water logged with fresh or saline water that supports characteristic animals and plants. In the dry lands of eastern Africa, wetlands cover about 3 percent of the total land area and include shallow lakes and margin s of deep lakes, swamps and marshes found on upper flood plains of major rivers, coastal river flood plains and high mountain peat bogs and tarns (Omoding 1995). These ecosystems support valuable biodiversity, including large numbers of mammals, reptiles, fishes and birds as well as diverse plant communities (Denny 1993). They also provide valuable resources and environmental benefits, such as biomass cropping for livestock pasture, water supply, agriculture, fisheries and subsistence hunting of wildlife that sustain local economies and communities (Shumway 1999).

Gichuki NN, Macharia JM. "Participation of local communities in the management of wetland resources in semi-arid areas: a case study of Magadi area, Kenya.". In: Conserving Biodiversity in Arid Regions. Boston: Kluwer Academic Publishers; 2003.
Gichuki FN;, Mungai DN;. Environmental impact assessment for water development and conservation..; 2000. AbstractWebsite

The possible environmental impacts of water development projects and land use practices such as deforestation and over grazing on water supply in Kenya are reviewed. Measures that can be taken in conjunction with properly conducted environmental impact assessments to mitigate adverse impacts are suggested

GICHUKI MRMUCHIRI. "Gichuki Muchiri. 1981 . Farm Machinery Manufacture and use in Kenya. United Nations Industrial Development Organization , Kenya Position paper.". In: Oral presentation, AFRA IV (RAF/4/009) Regional Meeting on Current and Future Activities in Maintenance and Repair of Nuclear Instruments. Arusha, Tanzania: 28th February to 2nd March 1994. University of Nairobi.; 1981.
Gichuki N. "Enforcement of Intellectual Property Rights.". In: Intellectual Property in Practice Workshop organised by IDLO. Nakuru; 2006.
Gichuki FN;, Mungai DN;, Gachene CKK. Some" near-farmer" research on land and water management for crop production in semi-arid Kenya..; 2000. AbstractWebsite

This paper describes a "near-farmer" applied research project working on 10 field stations scattered through the arid and semi-arid lands of Embu, Meru and Isiolo Districts of Esatern Province, Kenya. The objective of the research was to define better extension messages for resource-poor farmers to enable them to improve their land and water management techniques for improved and sustained yields. Most of the trials related to soil fertility and soil moisture, as well as trials on the use of Vetiver grass for soil conservation, control of the legume root parasite Alectra vogelii, and new introductions such as groundnuts, simsim (sesame), tubers, fodder crops and fruits.

Gichuki FN;, Mungai DN;. Effectiveness of three grass species as filter strips for soil conservation on cropland..; 2000. AbstractWebsite

The effectiveness of different grass spp. in reducing runoff and soil loss was studied at Kabete campus, University of Nairobi, Kenya. Half metre wide strips of Napier grass (Pennisetum purpureum), Nandi setaria (Setaria anceps) and tall Signal grass (Brachiaria ruziziensis) were established on 11m x 2m runoff plots, and runoff and soil loss were monitored for each rainfall event during the long and short rains of 1990. In terms of runoff control, there was no significant difference between treatments during early establishment; however, runoff form plot with filter strips was always lower than controls. B. ruziziensis was most effective at runoff and soil loss reduction and this was attributed to growth habit and slow rate of establishment. The capability of the strips to impede runoff improved with time.

GICHUKI MRMUCHIRI. "Gichuki Muchiri et al. 1994. Methodological Guidelines for Agricultural mechanisation strategy formulation , AGROTEC and FAO.". In: Oral presentation, AFRA IV (RAF/4/009) Regional Meeting on Current and Future Activities in Maintenance and Repair of Nuclear Instruments. Arusha, Tanzania: 28th February to 2nd March 1994. University of Nairobi.; 1994.
Gichuki N. "Mainstreaming the Youth in Local Governance.". In: Consultative Workshop organized by Africa Youth Trust. Nairobi; 2008.
Gichuki FN;, Mungai DN;, Gachene CKK. Residual effect of lucerne on wheat yield: report of a farm trial at Njoro, Nakuru district..; 2000. AbstractWebsite

This paper presents results from a trial in Swara Farm, Njoro, Kenya, in which a field was sown with Sorghum almum on a volcanic ash soil. Immediately after sowing, 14 strips measuring 156 m x 9 m were marked out and alternate strips were oversown with inoculated seed of lucerne cv. Hairy Peruvian. During the first year of the trial no differences were noticed in the growth of S. almum, but during the second year it grew better when associated with lucerne. After two years the field was ploughed and sown with wheat. The strips were harvested separately with a combine harvester. Mean yields after S. almum were 2,708 kg/ha and after the S.almum/lucerne mixture were 3,244 kg/ha.

Gichuki FN;, Mungai DN;, Gachene CKK. The range management handbook of Kenya: a database for planning development in arid and semi-arid areas of Kenya..; 2000. AbstractWebsite

This paper briefly presents a methodology for planning development in arid and semi-arid areas. It highlights the issues of problem identification and assessment of the natural and socio-economic environment, and describes the database contained in the Range Management Handbook. The handbook makes available baseline data for planning development in arid and semi-arid areas following a successful Farm Management Handbook that covers the high- and medium-potential areas of Kenya. In three parts, the Range Management Handbook covers: the status, principles and applications in Kenya; texts and maps relating to climate, landforms and soils, vegetation types, water sources, range unit inventory, livestock marketing and human ecology; special reports (guide to tolerant plants, pictorial key for goat stocking rates, large scale remote monitoring of vegetation, and a survey method for classification of range conditions) relevant to land planning and use in arid and semi-arid areas

Gichuki FN;, Mungai DN;, Gachene CKK;, Thomas DB. Some conceptions about sediment rating equations..; 2000. AbstractWebsite

This paper examines the anomalies in the sedimentation rating equations in terms of existing notions of statistical analysis and concludes that c=aqb is the preferred relationship. The method of estimating parameters a and b through ordinary least squares and the method of prediction using the log normal probability distribution of the error component z (c=aqbz) is presented using data for the Mathare river at Kabete, Kenya. The need for nonlinear least squares for estimation of parameters a and b is discussed in relation to the additive nature of the error component (c=aqb + z) n the nonlinear form of rating equation. The equation c=Faqb (where F is a correction factor arising due to log normal distribution of the error term z) predicted the sediment yield of the Mathare catchment quite well for 61 days during the long rainy season of 1991.

Gichuki FN;, Mungai DN;. Effect of micro-catchment size on survival and growth of two semiarid tree species..; 2000. AbstractWebsite

The effects of three different micro-catchment sizes on survival and growth of plant species was assessed and success in establishment and growth of Croton megalocarpus and Cassia spectabilis was compared in a semi-arid region of Kitui District, Kenya. Both species were planted in 25 x 25 cm, 45 x 45 cm, and 65 x 65 cm spherical micro-catchments. Height and diameter were measured and a survival count was taken. Results show that then micro-catchment size influenced (P>0.05) lateral growth of both species. Lateral growth of C. spectabilis in the smaller two micro-catchments (3.66 and 4.60 cm, resp.) was not significantly different (P>0.05), but was less than in the largest micro-catchment(5,31 cm). These results indicate that the two species are suitable for afforestation in these areas and that their survival is not limited by provision of a catchment in the area.

Gichuki FN;, Mungai DN;. Impacts of land-use practices on natural forests and watersheds in the lake Nakuru catchment basin..; 2000. AbstractWebsite

Trends in land use practices in the Lake Nakuru catchment area and, in particular, the causes and impacts of deforestation, which threaten the lake's unique ecology. It addresses the importance of natural forests for the successful management of the lake's watershed area. Findings are all discussed in the broader, national context and some suggestions for programmes of action to alleviate problems caused by deforestation are presented.

Gichuki FN;, Gachene CKK, Mungai DN;. Peoples' participation in agroforestry: the case of the Pokot..; 2000.Website
GICHUKI MRMUCHIRI. "Gichuki Muchiri. 2004Conservation Tillage and Food production in Semiarid Tropics of Africa: Kenyan case study. Paper presetted in the annual meeting, of American Society of Agronomy, SEATTLE U.S.A.". In: Oral presentation, AFRA IV (RAF/4/009) Regional Meeting on Current and Future Activities in Maintenance and Repair of Nuclear Instruments. Arusha, Tanzania: 28th February to 2nd March 1994. University of Nairobi.; 2004.
Gichuki N. "The Paradox in the Implementation Matrix in Capital Markets Reform in Kenya.". In: Emerging Trends in Commercial & Financial Law Workshop. KCB Leadership Centre, Karen, Nairobi; 2011.
Gichuki FN;, Mungai DN;, Gachene CKK. Soil erosion and conservation activities on land affected by road drainage: a case study of Nyeri District..; 2000. AbstractWebsite

The existing soil erosion damage caused by water drained from minor roads in the Nyeri District of Kenya was assessed and the soil conservation works needed to stabilize the waterways and gullies along the roads are specified. The study evaluated the land affected by road drains/culverts on 25 minor roads with a total length of 149 km. Of the total of 321 culverts identified, 171 (53%) were found to require channel rehabilitation. 68% of the culverts discharged onto steep slopes (>10%). Erosion was found to be more severe in the coffee-growing zones than in tea-growing areas. In the plateau areas, soil erosion from the culvert outlets was minimal. Due to gentle slopes and more perennial vegetation. 20,346 m of channel excavation was needed to provide artificial waterways for the discharge of water drained from the roads. Channel stabilization with grass cover or installation of scour checks was necessary on very gentle slopes. Steep slopes required stone check-dams and single-row post/stone check-dams. Very steep slopes also required lock-and-spill drains and post/stone/wire check-dams. Gabions (57 crossings) were needed mainly for rehabilitation of large gullies along with double-row post/stone check-dams and post/stone/wire check dams. Cut-off drains were necessary in some cases to divert water from the culvert outlets. In areas where vegetation was easily accessible, brushwood check-dams could be used.

Gichuki FN;, Mungai DN;. Development of a multi-disciplinary approach to improve the management of soil fertility by smallholder farmers: experience of the TSBF programme..; 2000. AbstractWebsite

This paper outlines the development of a new methodology to modify and improve the indigenous practices of soil fertility management in Eastern and Southern Africa and suggests requirements for involvement by collaborating institutions. It provides a brief history of the Tropical Soil Biology and Fertility (TBSF) Programme in Africa, ongoing resource integration work in Zimbabwe, proposed work in Kenya and team development in Zimbabwe.

Gichuki NN. Wetlands: Our common property.; 1999.
Gichuki JW, Opiyo R, Mugyenyi P, Namusisi K. "Healthcare providers’ level of involvement in provision of smoking cessation interventions in public health facilities in Kenya." Journal of Public Health in Africa. 2016.
Gichuki N. Banking Law: Cases and Materials.; Forthcoming.
Gichuki FN;, Mungai DN;, Gachene CKK;, Thomas DB. Use of soil survey information in soil and water management..; 2000. AbstractWebsite

The results of soil surveys at the ICIPE research site at Ungoye, South Nyanza, and the Ngori Ngori toposequence in Narok, Kenya, are discussed to provide insight into the applicability of soil survey information to soil and water management. It is concluded that soil survey information in soil and water management programmes can be used through understanding and appreciation of the criteria used in categorizing soils and their management implications. From the examples given it is noted that chemical aspects of the soil should be viewed not just as a means to assess its fertility, but also as a base to predict the behaviour of the soils when subjected to different types of management.

Gichuki FN;, Mungai DN;. Factors affecting land use and crop production in Botswana..; 2000. AbstractWebsite

This paper looks at factors which influence land allocation and crop production patterns in Botswana, across traditional and commercial farmers. It found that, among smallholder traditional farmers, less land is used (on average 5.6 ha) and is subdivided into the growing of three major crops: sorghum, maize and beans, with more land allocated to sorghum, the main staple and more adaptable to the climate. The small amount of cultivated land is attributed to lack of capital, transport and labour. Although large areas of land are owned by commercial farmers a high percentage is left idle due to constraints such as poor marketing systems, poor storage facilities and shortage of labour.

Gichuki CM, Gichuki NN. Comparative ecology and morphology of snipes (Family Scolopacidae) in Africa. . Bonn: Bonn Zoological Monographs; 2000.
Gichuki FN;, Mungai DN;, Gachene CKK;, Thomas DB. "Land and water management in Kenya: towards sustainable land use.".; 2000. Abstract

Preliminary findings on the effects of land use in the Masinga Dam catchment, Kenya, on the storage capacity of the reservoir are presented. Remote sensing and GIS techniques, supplemented with ground reports, were used to determine areas most susceptible to erosion. A representative catchment was then chosen for rainy season monitoring of soil loss, river suspended sediments and discharge response to rainfall. In addition, Gerlach-type traps were used to evaluate erosion rates under different crop covers and slope gradients. A sample of 200 households was interviewed about their perceptions of erosion problems on their farms. Preliminary results suggest that the major sediment-contributing areas are the densely populated and intensively cultivated foothills of the Aberdares, rather than the semi-arid lowlands directly bordering the reservoir. Poorly drained sealed and murram roads, together with footpaths, cattle tracks and gullies, act as extensions of the drainage network during storms, channelling sediment-laden runoff from bare areas around homesteads and schools directly into the river. Subsistence crops, particularly mono-cropped maize, appear to provide poor cover for a major part of the wet season.

Gichuki FN;, Mungai DN;. Erosion scars caused by earthflows: a case study of Ol Joro Orok division, Nyandarua district.; 2000. AbstractWebsite

This paper describes earthflow features in Nyairoko sub-location of Ol Joro Orok Division, Kenya. In 1989 more than 900 earthflows were counted in Nyandarua District, most of them in Ol Joro Orok and Ol Kalou Divisions. Individual flows affected areas between a few square metres and two hectares. More than 50% of the farms in the area were affected by earthflows. Such earthflows occurred only on grazing land and on convex slopes and were usually the result of extremely slow processes. Soils in the area are mainly moderately well drained, dark reddish brown Luvisols and well-drained, red to reddish-brown Nitisols. The first visible signs were usually shallow scars along the contour, breaking up the grass vegetation. Subsequent soil movement was very gradual. According to old residents of the area some of the earthflow features had been observed as long as 60 years ago and could not be attributed to land use change. One earthflow studied in detail revealed that soil stratification impeded drainage, leading to oversaturation of the topsoil layers and that seasonal subsurface flow generally seemed to be responsible for the soil movement. No obvious triggering could be identified.

GICHUNGE DRHEZEKIAH. "Gichunge, H. (1991): Value Engineering and Constructibility Improvement Studies. A Paper presented in a workshop on Project Management, Construction and Architecture, FADD, University of Nairobi.". In: Nairobi Journal of Management. Volume 6, PP 117-145. GIGA German Institute of Global and Area Studies, Hamburg, July 2009; 1991. Abstract
This integrative review on the teaching of reading in Kenyan primary schools provides a foundation for the growing movement there to improve reading education. In gathering sources for this review, we took an inclusive historical stance. Thus, we did not dismiss research reports that lacked traditional indicators of quality such as being published in peer-reviewed journals. We used multiple methods to find relevant research and associated documents, including two trips to Kenya. The review is organized by six topics: (a) language of instruction, (b) reading instruction, (c) reading materials, (d) reading culture, (e) assessment, and (f) teacher development. The review concludes with six proposals for policymakers, educational researchers, and teacher educators for the development of reading instruction based on what we learned in reviewing the literature. The first proposals are intended specifically to address the teaching of reading in Kenya, but they may be relevant to other sub-Saharan nations. The final proposal encourages others to conduct similar reviews to make possible a handbook of reading in Africa.
GICHUNGE DRHEZEKIAH. "Olima, W.H.A and Gichunge, H. Emerging Environmental concerns in Nairobi: The Case of East African Towns in transition, GLCA/UON Symposium, from 17th -19th June 2002, Heritage Voyager Hotel in Mombasa.". In: Nairobi Journal of Management. Volume 6, PP 117-145. GIGA German Institute of Global and Area Studies, Hamburg, July 2009; 2002. Abstract
This integrative review on the teaching of reading in Kenyan primary schools provides a foundation for the growing movement there to improve reading education. In gathering sources for this review, we took an inclusive historical stance. Thus, we did not dismiss research reports that lacked traditional indicators of quality such as being published in peer-reviewed journals. We used multiple methods to find relevant research and associated documents, including two trips to Kenya. The review is organized by six topics: (a) language of instruction, (b) reading instruction, (c) reading materials, (d) reading culture, (e) assessment, and (f) teacher development. The review concludes with six proposals for policymakers, educational researchers, and teacher educators for the development of reading instruction based on what we learned in reviewing the literature. The first proposals are intended specifically to address the teaching of reading in Kenya, but they may be relevant to other sub-Saharan nations. The final proposal encourages others to conduct similar reviews to make possible a handbook of reading in Africa.
GICHUNGE DRHEZEKIAH. "Factors that contribute to cost of provision of low cost housing in Nairobi, Kenya. Published conference proceedings on Low Cost Housing I, CMTSI, PP 1-12, International Conference on Spatial Information for Sustainable Development, Nairobi, Kenya, 2-5th .". In: Nairobi Journal of Management. Volume 6, PP 117-145. GIGA German Institute of Global and Area Studies, Hamburg, July 2009; 2001. Abstract
This integrative review on the teaching of reading in Kenyan primary schools provides a foundation for the growing movement there to improve reading education. In gathering sources for this review, we took an inclusive historical stance. Thus, we did not dismiss research reports that lacked traditional indicators of quality such as being published in peer-reviewed journals. We used multiple methods to find relevant research and associated documents, including two trips to Kenya. The review is organized by six topics: (a) language of instruction, (b) reading instruction, (c) reading materials, (d) reading culture, (e) assessment, and (f) teacher development. The review concludes with six proposals for policymakers, educational researchers, and teacher educators for the development of reading instruction based on what we learned in reviewing the literature. The first proposals are intended specifically to address the teaching of reading in Kenya, but they may be relevant to other sub-Saharan nations. The final proposal encourages others to conduct similar reviews to make possible a handbook of reading in Africa.
GICHUNGE DRHEZEKIAH. "Gichunge, H. and Aligula, M.E.(2003): .". In: Politics and Political Science (Online Publication), Vol. 43, Number 1, January 2010. GIGA German Institute of Global and Area Studies, Hamburg, July 2009; 2003. Abstract
This integrative review on the teaching of reading in Kenyan primary schools provides a foundation for the growing movement there to improve reading education. In gathering sources for this review, we took an inclusive historical stance. Thus, we did not dismiss research reports that lacked traditional indicators of quality such as being published in peer-reviewed journals. We used multiple methods to find relevant research and associated documents, including two trips to Kenya. The review is organized by six topics: (a) language of instruction, (b) reading instruction, (c) reading materials, (d) reading culture, (e) assessment, and (f) teacher development. The review concludes with six proposals for policymakers, educational researchers, and teacher educators for the development of reading instruction based on what we learned in reviewing the literature. The first proposals are intended specifically to address the teaching of reading in Kenya, but they may be relevant to other sub-Saharan nations. The final proposal encourages others to conduct similar reviews to make possible a handbook of reading in Africa.
GICHUNGE DRHEZEKIAH. "Gichunge H. (1993): International Contracting for the Construction Industry in changing times. A paper presented in A.A.K Professional Practice Conference on 29th .". In: Nairobi Journal of Management. Volume 6, PP 117-145. GIGA German Institute of Global and Area Studies, Hamburg, July 2009; 1993. Abstract
This integrative review on the teaching of reading in Kenyan primary schools provides a foundation for the growing movement there to improve reading education. In gathering sources for this review, we took an inclusive historical stance. Thus, we did not dismiss research reports that lacked traditional indicators of quality such as being published in peer-reviewed journals. We used multiple methods to find relevant research and associated documents, including two trips to Kenya. The review is organized by six topics: (a) language of instruction, (b) reading instruction, (c) reading materials, (d) reading culture, (e) assessment, and (f) teacher development. The review concludes with six proposals for policymakers, educational researchers, and teacher educators for the development of reading instruction based on what we learned in reviewing the literature. The first proposals are intended specifically to address the teaching of reading in Kenya, but they may be relevant to other sub-Saharan nations. The final proposal encourages others to conduct similar reviews to make possible a handbook of reading in Africa.
GICHUNGE DRHEZEKIAH. "Mbeche, I.M. and Gichunge, H. (2003): Risk Management in Building projects: An Analysis of time and Cost Risks.". In: Nairobi Journal of Management. Volume 6, PP 117-145. GIGA German Institute of Global and Area Studies, Hamburg, July 2009; 2003. Abstract
This integrative review on the teaching of reading in Kenyan primary schools provides a foundation for the growing movement there to improve reading education. In gathering sources for this review, we took an inclusive historical stance. Thus, we did not dismiss research reports that lacked traditional indicators of quality such as being published in peer-reviewed journals. We used multiple methods to find relevant research and associated documents, including two trips to Kenya. The review is organized by six topics: (a) language of instruction, (b) reading instruction, (c) reading materials, (d) reading culture, (e) assessment, and (f) teacher development. The review concludes with six proposals for policymakers, educational researchers, and teacher educators for the development of reading instruction based on what we learned in reviewing the literature. The first proposals are intended specifically to address the teaching of reading in Kenya, but they may be relevant to other sub-Saharan nations. The final proposal encourages others to conduct similar reviews to make possible a handbook of reading in Africa.
Gichure, J. N. KMICNPM. "Standardization of cut size and pre-drying time of beef to mainstream pastoral processing in Kenya’s meat industry." Pastoralism: Research, Policy and Practice. 2017;7:1-7.
Gichure, N.G., Wahome, R.G., Njage, P.K., Karuri, H. W., Nzuma, M.J., Karantininis, K. "Factors influencing extent of traceability along organic fresh produce value chains: case of kale in Nairobi, Kenya." Organic Agriculture. 2017;7(3):293-302.
kariuki james gichuru. "The gender implications of men’s shift from cash-crop farming to dairy farming in Central Kenya." International Journal of Social Sciences and Entrepreneurship. 2013;1(5):631-646.
Gichuru L, Ininda J, Njoroge K. "Maize streak virus (MSV) disease expression in F1 hybrids of diverse genotypes.". In: 10th KARI biennial conference. Nairobi, Kenya ; 2007.
Gichuru EK;, Combes MC;, Mutitu EW;, Ngugi ECK;, Omondi CO;, Bertrand B;, Lashermes P. Towards the development of sequence based markers for resistance to coffee berry disease (Colletotrichum kahawae).; 2009. AbstractWebsite

Coffee Berry Disease which affects green Arabica coffee (Coffea arabica) berries is caused by the fungus Colletotrichum kahawae and is a major problem in Arabica coffee production in African countries. Breeding for resistance to this disease is therefore to a major priority in these countries avoid intensive chemical usage for its control. Recently, microsatellite and Amplified Fragment Length Polymorphisms (AFLP) markers for a gene conferring resistance to the disease were identified and mapped onto the chromosomal region carrying the gene. To improve the repeatability of the AFLP markers, four of the marker bands were selected for cloning and sequencing to facilitate specific primers to be designed. Three of the resultant primers did not amplify products that exhibited polymorphism characteristic of the parent AFLP bands; but one primer pair amplified a product that dominantly identified the presence of the parent AFLP marker at an optimum temperature of 62°C followed by electrophoresis in agarose. The reliability of the designed primers was confirmed by analysis in 95 plants from a F2 population previously used to map the chromosomal fragment carrying the resistance. The importance of the results in enhancing the utility of the parent AFLP marker in relation to analytical costs and position on the chromosomal fragment is discussed.

Gichuru L, Derera J, Njoroge K. "The incidence of diseases and other constraints found in small-scale maize cropping systems of Kenya-midlands.". In: Annual Joint Meeting of the National Association of Plant Breeders (NAPB), and the Plant Breeding Coordinating Committee PBCC).; 2012.
Gichuyia LN. "NAIROBI CITY MARKET: AN ELASTIC ARCHITECTURE AND URBAN DE- SIGN EXPERIENCE ACROSS TIME AND SPACE.". In: NAIROBI CITY MARKET: AN ELASTIC ARCHITECTURE AND URBAN DE- SIGN EXPERIENCE ACROSS TIME AND SPACE. Leuven, Belgium: Leuven University Press ; 2019.
Gichuyia LN. INDOOR OVERHEAT- ING RISK: A FRAMEWORK FOR TEMPORAL BUILDING ADAPTATION DECISION-MAKING. Cambridge, London: University of Cambridge - https://doi.org/10.17863/CAM.17146; 2017.
Gichuyia LN. "THE IMPACT OF CLIMATE CHANGE ON THE INDOOR OVERHEATING RISK LANDSCAPE OF NAIROB.". In: In Proceedings of the Annual Architecture and Engineering Conference - Business opportunities in Energy, Manufacturing, Infrastructural and Environmental Research. School of Engineering, University of Nairobi, Kenya; 2019.
Gichuyia LN, Madette E. "OCHA: THE EAST AFRICAN COUNTRYSIDE FORMS.". In: OCHA: THE EAST AFRICAN COUNTRYSIDE FORMS. Rotterdam, Netherlands: OMA/AMO Press; 2019.
Gichuyia LN. "INDOOR OVERHEATING RISK ANALYSIS OF OFFICE BUILDINGS IN NAI- ROBI IN A CHANGING CLIMATE.". In: Annual Eastern Africa Architecture Workshop and Exhibition. ADD Building - University of Nairobi; 2019.
Gichuyia LN. BOOSTING INTERCON- TINENTAL RELATIONS _ LESSONS FROM BUILDING PHYSICS. Wilhelm Kempff house- Casa Orfeo, Positano -Italy,; 2019.
Gichuyia LN. "LESSONS LEARNT FROM THERMAL DATA-LOGGING OF BUILDINGS IN NAIROBI OVER THE YEARS; HIGHLIGHT- ING THE DEMAND FUNCTIONS FOR DECI- SION-SUPPORT.". In: Annual Eastern Africa Architecture Workshop and Exhibition. ADD Building - University of Nairobi; 2019.
Gikonyo NK, Hassanali A, Njagi PGN, Peter M, Midiwo JO. "Odor Composition of Preferred (Buffalo and Ox) and Nonpreferred (Waterbuck) Hosts of Some Savanna Tsetse Flies.". 2002. Abstracthttp://erepository.uonbi.ac.ke:8080/xmlui/handle/123456789/36947

A previous study on the feeding responses of tsetse flies, Glossina morsitans morsitans, implicated the existence of allomonal barriers, both volatile and nonvolatile, on the nonpreferred host, waterbuck, Kobus defassa. In the present study, electroantennogram-active compounds in odors from waterbuck were compared with those of two preferred hosts of tsetse flies, buffalo, Syncerus caffer, and ox, Bos indicus. Odors from the three bovids were trapped on activated charcoal and/or reverse-phase (octadecyl bonded) silica and analyzed with a gas chromatography-linked electroantennographic detector (GC-EAD) and, where possible, identified by using gas chromatography-linked mass spectrometry (GC-MS) and chromatographic comparisons with authentic samples. The GC-EAD profiles (with G. m. morsitans antennae) of the odors of the two preferred hosts were comparable, comprising medium-chain, saturated or unsaturated aldehydes and phenols, with buffalo emitting a few more EAG-active aldehydes. Waterbuck odor gave a richer profile, consisting of fewer aldehydes but more phenolic components and a series of 2-ketones (C8–C13) and δ-octalactone. This bovid also emits moderate amounts of C5–C9 straight-chain fatty acids, some of which were detected in buffalo and ox only in trace amounts. However, these did not elicit significant GC-EAD responses. Waterbuck profiles from the antennae of G. pallidipes showed broad similarity to those from G. m. morsitans, although the composition of aldehydes and ketones was somewhat different, indicating species-specific difference in the detection of host odors. Certain waterbuck-specific EAG-active components, particularly the 2-ketones and lactone, constitute a candidate allomonal blend in waterbuck odor.

Gikonyo J, Kibegwa F, Inyangala B. "Comparative assessment of hatching rates of African Catfish (Clarias gariepinus) eggs using Nile cabbage and kaka bans substrates." Livestock Research for Rural Development. 2017;29. Abstract
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Gikonyo EW, p o Oduor OS, Kanyanjua SM, Keter JKA. "Phosphate sorption by some kenyan soils as evaluated by the langmuir and freundlich adsorption equations.". 2000. Abstract

The sorption of added inorganic phosphate (P) by eight soils which varied appreciably in their ability to sorb P was evaluated using the Langmuir and Freundlich adsorption equations. When the sorption data were plotted according to the conven¬tional Langmuir and linear Freundlich equations, linear relationships were obtained. Regression analysis was used to compute the straight lines obtained. The Freundlich equations gave significantly to highly significantly correlation coefficients (r2 = 0.509 - 0.972) in all the soils tested while the Langmuir equation was non-sig¬nificant in the highest and lowest sorbing soils (r2 0.004 and 0.453 respectively) but was highly to very highly significant in the other soils (r2 = 0.816 - 0.988). The Freundlich equation was, therefore, ade¬quate in describing the sorption data in all the soils tested but with varying precision as shown by the different correlation coeffi¬cients. A comparison of the two equations indicated that Freundlich equation gives the best fit in majority of soils and would, therefore, be recommended for estimating the P-sorption characteristic of soils tested in this work.

Gikonyo NW, Ndiritu AW NG. "Transformational leadership practices of school principals: Does school ownership matter?". In: Second Annual International Interdisciplinary Conference. Catholic University of Eastern Africa (CUEA),; . CUEA, Kenya; 2013.
GikonyoNW NAW. "Inspiring a shared vision: getting all the teachers in the bandwagon." Journal of Education and Practice . 2014;5(5).
Gikungu M, Nyamasyo G, Muturi J, Mbugi JP, Mueke J, Jan Langerlof, Mungatu J. "Collembola Richness And Diversity Along A Gradient Of Land-use Intensity And Soil Abiotic Factors In Taita, Kenya.". 2009.Website
Gikunju M, Nyamato-Kwenda R, Kwanya T. "A review of citizen librarianship in academic libraries in Kenya.". In: Digital Technologies for Information and Knowledge Management. Nairobi: Technical University of Kenya; 2019.
Gikunju M. Open Access Initiatives .; 2014.
Gikunju M. Open Access Resources .; 2015.
Gilbert HF, O'Leary MH. "Modification of arginine and lysine in proteins with 2,4-pentanedione." Biochemistry. 1975;14(23):5194-9. Abstract

Primary amines react with 2,4-pentanedione at pH 6-9 to form enamines, N-alkyl-4-amino-3-penten-2-ones. The latter compounds readily regenerate the primary amine at low pH or on treatment with hydroxylamine. Guanidine and substituted guanidines react with 2,4-pentanedione to form N-substituted 2-amino-4,6-dimethylpyrimidines at a rate which is lower by at least a factor of 20 than the rate of reaction of 2,4-pentanedione with primary amines. Selective modification of lysine and arginine side chains in proteins can readily be achieved with 2,4-pentanedione. Modification of lysine is favored by reaction at pH 7 or for short reaction times at pH 9. Selective modification of arginine is achieved by reaction with 2,4-pentanedione for long times at pH 9, followed by treatment of the protein with hydroxylamine. The extent of modification of lysine and arginine side chains can readily be measured spectrophotometrically. Modification of lysozyme with 2,4-pentanedione at pH 7 results in modification of 3.8 lysine residues and less than 0.4 arginine residue in 24 hr. Modification of lysozyme with 2,4-pentanedione at pH 9 results in modification of 4 lysine residues and 4.5 arginine residues in 100 hr. Treatment of this modified protein with hydroxylamine regenerated the modified lysine residues but caused no change in the modified arginine residues. One arginine residue seems to be essential for the catalytic activity of the enzyme.

Gilbert-Kawai ET, Milledge JS, Grocott MPW, Martin DS. "King of the {Mountains}: {Tibetan} and {Sherpa} {Physiological} {Adaptations} for {Life} at {High} {Altitude}." Physiology. 2014;29:388-402. AbstractWebsite

Anecdotal evidence surrounding Tibetans' and Sherpas' exceptional tolerance to hypobaric hypoxia has been recorded since the beginning of high-altitude exploration. These populations have successfully lived and reproduced at high altitude for hundreds of generations with hypoxia as a constant evolutionary pressure. Consequently, they are likely to have undergone natural selection toward a genotype (and phenotype) tending to offer beneficial adaptation to sustained hypoxia. With the advent of translational human hypoxic research, in which genotype/phenotype studies of healthy individuals at high altitude may be of benefit to hypoxemic critically ill patients in a hospital setting, high-altitude natives may provide a valuable and intriguing model. The aim of this review is to provide a comprehensive summary of the scientific literature encompassing Tibetan and Sherpa physiological adaptations to a high-altitude residence. The review demonstrates the extent to which evolutionary pressure has refined the physiology of this high-altitude population. Furthermore, although many physiological differences between highlanders and lowlanders have been found, it also suggests many more potential avenues of investigation.

Gilbert-Kawai ET, Milledge JS, Grocott MPW, Martin DS. "King of the {Mountains}: {Tibetan} and {Sherpa} {Physiological} {Adaptations} for {Life} at {High} {Altitude}." Physiology. 2014;29:388-402. AbstractWebsite

Anecdotal evidence surrounding Tibetans' and Sherpas' exceptional tolerance to hypobaric hypoxia has been recorded since the beginning of high-altitude exploration. These populations have successfully lived and reproduced at high altitude for hundreds of generations with hypoxia as a constant evolutionary pressure. Consequently, they are likely to have undergone natural selection toward a genotype (and phenotype) tending to offer beneficial adaptation to sustained hypoxia. With the advent of translational human hypoxic research, in which genotype/phenotype studies of healthy individuals at high altitude may be of benefit to hypoxemic critically ill patients in a hospital setting, high-altitude natives may provide a valuable and intriguing model. The aim of this review is to provide a comprehensive summary of the scientific literature encompassing Tibetan and Sherpa physiological adaptations to a high-altitude residence. The review demonstrates the extent to which evolutionary pressure has refined the physiology of this high-altitude population. Furthermore, although many physiological differences between highlanders and lowlanders have been found, it also suggests many more potential avenues of investigation.

Gilbert-Kawai ET, Milledge JS, Grocott MPW, Martin DS. "King of the {Mountains}: {Tibetan} and {Sherpa} {Physiological} {Adaptations} for {Life} at {High} {Altitude}." Physiology. 2014;29:388-402. AbstractWebsite

Anecdotal evidence surrounding Tibetans' and Sherpas' exceptional tolerance to hypobaric hypoxia has been recorded since the beginning of high-altitude exploration. These populations have successfully lived and reproduced at high altitude for hundreds of generations with hypoxia as a constant evolutionary pressure. Consequently, they are likely to have undergone natural selection toward a genotype (and phenotype) tending to offer beneficial adaptation to sustained hypoxia. With the advent of translational human hypoxic research, in which genotype/phenotype studies of healthy individuals at high altitude may be of benefit to hypoxemic critically ill patients in a hospital setting, high-altitude natives may provide a valuable and intriguing model. The aim of this review is to provide a comprehensive summary of the scientific literature encompassing Tibetan and Sherpa physiological adaptations to a high-altitude residence. The review demonstrates the extent to which evolutionary pressure has refined the physiology of this high-altitude population. Furthermore, although many physiological differences between highlanders and lowlanders have been found, it also suggests many more potential avenues of investigation.

Gilbert-Kawai ET, Milledge JS, Grocott MPW, Martin DS. "King of the {Mountains}: {Tibetan} and {Sherpa} {Physiological} {Adaptations} for {Life} at {High} {Altitude}." Physiology. 2014;29:388-402. AbstractWebsite

Anecdotal evidence surrounding Tibetans' and Sherpas' exceptional tolerance to hypobaric hypoxia has been recorded since the beginning of high-altitude exploration. These populations have successfully lived and reproduced at high altitude for hundreds of generations with hypoxia as a constant evolutionary pressure. Consequently, they are likely to have undergone natural selection toward a genotype (and phenotype) tending to offer beneficial adaptation to sustained hypoxia. With the advent of translational human hypoxic research, in which genotype/phenotype studies of healthy individuals at high altitude may be of benefit to hypoxemic critically ill patients in a hospital setting, high-altitude natives may provide a valuable and intriguing model. The aim of this review is to provide a comprehensive summary of the scientific literature encompassing Tibetan and Sherpa physiological adaptations to a high-altitude residence. The review demonstrates the extent to which evolutionary pressure has refined the physiology of this high-altitude population. Furthermore, although many physiological differences between highlanders and lowlanders have been found, it also suggests many more potential avenues of investigation.

Gilbert-Kawai ET, Milledge JS, Grocott MPW, Martin DS. "King of the {Mountains}: {Tibetan} and {Sherpa} {Physiological} {Adaptations} for {Life} at {High} {Altitude}." Physiology. 2014;29:388-402. AbstractWebsite

Anecdotal evidence surrounding Tibetans' and Sherpas' exceptional tolerance to hypobaric hypoxia has been recorded since the beginning of high-altitude exploration. These populations have successfully lived and reproduced at high altitude for hundreds of generations with hypoxia as a constant evolutionary pressure. Consequently, they are likely to have undergone natural selection toward a genotype (and phenotype) tending to offer beneficial adaptation to sustained hypoxia. With the advent of translational human hypoxic research, in which genotype/phenotype studies of healthy individuals at high altitude may be of benefit to hypoxemic critically ill patients in a hospital setting, high-altitude natives may provide a valuable and intriguing model. The aim of this review is to provide a comprehensive summary of the scientific literature encompassing Tibetan and Sherpa physiological adaptations to a high-altitude residence. The review demonstrates the extent to which evolutionary pressure has refined the physiology of this high-altitude population. Furthermore, although many physiological differences between highlanders and lowlanders have been found, it also suggests many more potential avenues of investigation.

Gina Ziervogel, Opere A. "Integrating Meteorological and Indigenous Knowledge-based Seasonal Climate Forecasts for the Agricultural Sector." CCAA learning paper, 1. 2010. Abstractintegrating_meteorological_and_indigenous_knowledge-based_seasonal_climate_forecasts_for_the_agricultural_sector.pdfIDRC Digital Library

Extreme climatic events, such as droughts and floods, as well as changes in the mean climate, have a direct
effect on crops and livestock and, thus, people’s livelihoods. Food security is at risk, particularly in sub-saharan Africa where local production remains largely rain-fed. Given that climate variability is likely to increase with increasing greenhouse gas emissions, it is more important than ever to understand how this variability can be managed to reduce the negative consequences.

The impact is already significant. In Malawi, for example, as a result of the 2002 drought, approximately 5 million people needed emergency food aid, which took a long time to be delivered. A similar situation occurred in Niger in 2004–2005 when approximately 2.5 million people — or a fifth of the population — was in need of food rations (UNDP 2007). In 2009, approximately 3.8 million people in Kenya required food aid because of the prolonged drought (FEWS Net 2010). In 2006, sub-Saharan Africa accounted for 13% of the world’s population and 25% of the undernourished people in the developing world (FAO 2006).

Gioto V, Wandiga S, Oludhe C. "Determinants of Household Food Security Status and Challenges of Building Resilience to Climate Variability and Change Posed by Drought in Tharaka …." Handbook of Climate Change Resilience. 2018;2(1):1-29. Abstractlink.springer.com

Climate change and variability pose momentous severe threats to agricultural development and consequently to economic growth and increased poverty levels. In reference, this paper examines the determinants of household food security status and assesses the challenges of building resilience to climate variability and change posed by drought in Tharaka Nithi, Kenya. The study coverage is Tharaka North and Tharaka South sub-counties which are semiarid and cover an area of 1,569 square kilometers (km2) with a total population of 158,023 people; this is about 65% of Tharaka Nithi County (Kenya). The sub-counties have three main livelihood zones (LZs). These are marginal mixed farming at 52%, mixed farming at 38%, and rain-fed cropping at 10%.

The area is exposed to climate change, aggravated by minimal adaptive capacity. Climate variability and climate change threaten food production leading to about 20–30% of the population being in poor and borderline food consumption score. The year 2017 describes one of the cyclical drought situations with low productivity and depleted range land conditions exposing approximately 30,000 persons in need of humanitarian assistance. This study reflects on challenges of building resilience to climate variability and change posed by drought using a transdisciplinary approach. The problems of the household food security status were poor rainfall performance, high temperatures, low livestock prices, high food prices, poor crop production, poor pasture and browse quality, and inadequate water for both domestic and livestock use. The solutions to the above-listed issues lie in the increased advocacy, rainwater harvesting structures, marketing linkages, timely early warning knowledge management, and eco-based farming practices. The study also found that there was a significant relationship between the household level of education, family size, household income, and household head age with food security. Findings of this study will form a platform for policy makers.

Keywords
Climate variability Climate change Tharaka Nithi Drought and resilience

Gioto V, Wandiga S, Oludhe C. "Climate Change Detection across All Livelihood Zones in Tharaka Nithi County." Journal of Meteorology and Related Sciences. 2016;9(2):14-24. Abstractresearchgate.net

Kenyan agriculture is largely rain-fed and principally dependent on rainfall. According to FEWS NET report for Kenya in August 2010 based on historical data from 70 rainfall stations and 17 air temperature stations to interpolate the long-rains precipitation and temperature trends for all of Kenya from 1960 to 2009 (Funk et al, 2010). The FEWS NET report indicate that in Kenya long-rains traditionally occur between March and June and short rains in October to December. The authors report that Kenya has experienced trend of decreasing rainfall and rising temperatures as Sudan. In Central Kenya, one of the country’s key agricultural regions, the area receiving adequate rainfall to support reliable rain-fed agriculture has declined by roughly 45 per cent since the mid 1970s (Funk et al, 2010). This study investigates change in temperature and rainfall pattern across all livelihood zones in Tharaka Nithi County. Data was collected for 39 years (1976 - 2015) period for the area of Study and in addition divisions were made to three non overlapping climate period of 30 years (1982 - 1991, 1992 – 200 and 2002 - 2012). The data were subjected to Gaussian kernel analysis, moments, regression, and non-parametric approaches based on Mann-Kendal statistics to justify any change in the average monthly and annually rain fall and temperature trend. The results indicate common change points and transitions from wet to dry (upward shift). The test indicates rainfall variation over the study area is significant (p= 0.05).The study recommended on the use of the information for Agricultural development and general socio-economic improvement.

Gisore JO, Khainga SO. "NEGATIVE PRESSURE WOUND THERAPY (NPWT) FOR THE MANAGEMENT OF LAPAROSTOMY WOUNDS: CASE SERIES." East Afr Med J. 2013;90(12):409-12. Abstract

Laparostomy or the open abdomen can be a lifesaving intervention in surgical emergencies for abdominal compartment syndrome, wound dehiscence, trauma and intra-abdominal sepsis. However, the open abdomen imposes a significant burden on nursing staff caring for these critically ill patients due to the large volume of exudate and fluid loss.To achieve mechanical containment of abdominal viscera and active removal of exudate, we used NPWT to manage five patients with complex intra-abdominal sepsis laparostomy wounds. It took between 12 to 28 days to achieve full granulation for secondary closure of the wounds. The series shows that in the management of laparostomy wounds, NPWT provides an easier way to manage the large volumes of exudates and reduces the frequency of dressings changes required with traditional wound dressings.

Gisore P, Kaseje D, Were F, Ayuku D. "Motivational Interviewing Intervention on Health-Seeking Behaviors of Pregnant Women in Western Kenya.". 2014;2(19):144-156. Abstractmotivational_interviewing_intervention_on.pdf

We studied the effect of using Motivational Interviewing Intervention (MII) on health facility delivery and newborn care practices among pregnant women receiving Care of the Mother and Newborn at Home (CNH) visits by Community Health Workers (CHWs). Near-Term women who had received at least one CHW home visit, were randomly assigned to one session of MII (intervention) or no MII (Control). Fifty five (55%) of intervention women, compared to 35% of control women delivered in health facilities. Intervention women also understood the need to breastfeed exclusively for 6 months better than controls (P = 0.000), and had a p-value of 0.07 for breastfeeding within one hour after birth. We concluded in the context of CHW Home visit program, adding may improve perinatal care.

Gisore P, Kaseje D, Were F, Ayuku D. "Motivational Interviewing Intervention on Health-Seeking Behaviors of Pregnant Women in Western Kenya." Applied Biobehavioral Research. 2014;19(2):144-156. Abstract

We studied the effect of using Motivational Interviewing Intervention (MII) on health facility delivery and newborn care practices among pregnant women receiving Care of the Mother and Newborn at Home (CNH) visits by Community Health Workers (CHWs). Near-Term women who had received at least oneCHWhome visit, were randomly assigned to one session of MII (intervention) or no MII (Control). Fifty five (55%) of intervention women, compared to 35% of control women delivered in health facilities. Intervention women also understood the need to breastfeed exclusively for 6 months better than controls (P = 0.000), and had a p-value of 0.07 for breastfeeding within one hour after birth. We concluded in the context of CHW Home visit program, adding may improve perinatal care.

GITAHI DRKIAMASTEPHEN. "Kiama, S. G., Cochand L., Gehr P., and L. P. Nicod (2000). Infection of human dendritic cells and human alveolar macrophages by Salmonella mutants, a potent vaccine delivery system. American Journal of Respiratory and Critical Care Medicine 161: A128.". In: Fifth NFP37 Somatic Gene Therapy meeting. Elsevier; 2000. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
GITAHI DRKIAMASTEPHEN. "Kiama, S. G., Bhattacharjee, J., Maina, J. N. and K. D. Weyrauch (1997). Surface specialisation of the capillary endothelium in the pecten oculi of the chicken, and their overt roles in pectineal haemodynamics and nutrient transfer to the inner neural ret.". In: Presented at the . Elsevier; 1997. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
GITAHI DRKIAMASTEPHEN. "Kiama, S. G., Cochand L., Karlsson L. M., Nicod L. P., and P. Gehr (2001). Evaluation of phagocytic activity in human monocyte-derived dendritic cells. Journal of Aerosol Medicine 14: 289-299.". In: Faculty of Veterinary Medicine Biennial Scientific Conference 2002. Elsevier; 2001. Abstract
Dendritic cells play a central role in initiation of primary T lymphocyte responses to foreign antigens. Their potency in antigen presentation vis-a-vis reported low or lack of ability to phagocytize particulate matter has limited our understanding of the role that they play in inducing immunity to particulate antigens. One hypothesis is that dendritic cells may possess a high phagocytic capacity when immature and located in peripheral tissues, which they lose on maturation. Our goal was to characterize the phagocytic capacity in human immature dendritic cells. The phagocytic capacity of human monocyte-derived immature dendritic cells was studied by morphological and morphometric means, and compared to that of professional phagocytes, human alveolar macrophages, their progenitors, the peripheral blood monocytes, and mature dendritic cells. Phagocytic index (proportion of phagocytic cells) was decreased by 42.8% (immature dendritic cells) and 74.2% (mature dendritic cells) with respect to monocytes. Similarly, the phagocytic index was decreased by 46.5% (immature dendritic cells) and 75.9% (mature dendritic cells) with respect to macrophages. Volume density of phagocytized particles was decreased by 76.1% (immature dendritic cells) and 96.7% (mature dendritic cells) with respect to the monocytes. However, volume density was decreased by 34.3% (immature dendritic cells) and 91% (mature dendritic cells) with respect to alveolar macrophages. These results show that human monocyte-derived immature dendritic cells possess a phagocytic capacity that is lower than that of peripheral blood monocytes and alveolar macrophages but higher than that of mature dendritic cells.
GITAHI DRKIAMASTEPHEN. "Kiama S. G. (1999). Dendritic cell-particle interaction and the potential application(s) in the lung.". In: Presented at the . Elsevier; 1999. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
GITAHI DRKIAMASTEPHEN. "Dreher, D., Kok M., C. Obregon, Kiama S. G., Gehr P., and L. P Nicod (2002). Salmonella virulence factor SipB induces activation and release of IL-18 in human dendritic cells. Journal of Leukocyte Biology 72:743-751.". In: Faculty of Veterinary Medicine Biennial Scientific Conference, 3rd to 5th November 2004. Elsevier; 2002. Abstract
Interleukin-18 (IL-18) plays an important role in innate and acquired immunity, in particular against intracellular pathogens. However, little is known about the microbial factors that trigger IL-18 secretion by dendritic cells (DCs). To determine the influence of bacterial virulence factors on the activation and release of IL-18, we infected human monocyte-derived DCs with virulence mutants of the facultative intracellular pathogen Salmonella typhimurium. Our results show that infection by S. typhimurium causes caspase-1-dependent activation of IL-18 and triggers the release of IL-18 in human DCs. The secretion of IL-18 by the DCs was closely correlated with the ability of the S. typhimurium strains to induce apoptosis. We demonstrate that activation and release of IL-18 are blocked by mutations in the Salmonella sipB gene, which encodes a virulence factor that activates caspase-1 to induce apoptosis. These findings indicate that the activation and release of IL-18 induced by bacterial virulence factors may represent one component of innate immunity against the intracellular bacteria.
Gitahi N, Kiarie J, Mecha J, Ilovi S. "Implementation of HIV discordant couple care and treatment program in a Kenyan referral hospital.". In: 8th IAS Conference on Pathogenesis, Treatment and Prevention, Vancouver, . Canada ; 2015.
GITAHI DRKIAMASTEPHEN. "Kiama S. G. (2001). Functional and Morphological Characterization of Particle .". In: Presented at the Institute of Anatomy, University of Bern, Bern, Switzerland on 15th May 2001. Elsevier; 2001. Abstract
Dendritic cells play a central role in initiation of primary T lymphocyte responses to foreign antigens. Their potency in antigen presentation vis-a-vis reported low or lack of ability to phagocytize particulate matter has limited our understanding of the role that they play in inducing immunity to particulate antigens. One hypothesis is that dendritic cells may possess a high phagocytic capacity when immature and located in peripheral tissues, which they lose on maturation. Our goal was to characterize the phagocytic capacity in human immature dendritic cells. The phagocytic capacity of human monocyte-derived immature dendritic cells was studied by morphological and morphometric means, and compared to that of professional phagocytes, human alveolar macrophages, their progenitors, the peripheral blood monocytes, and mature dendritic cells. Phagocytic index (proportion of phagocytic cells) was decreased by 42.8% (immature dendritic cells) and 74.2% (mature dendritic cells) with respect to monocytes. Similarly, the phagocytic index was decreased by 46.5% (immature dendritic cells) and 75.9% (mature dendritic cells) with respect to macrophages. Volume density of phagocytized particles was decreased by 76.1% (immature dendritic cells) and 96.7% (mature dendritic cells) with respect to the monocytes. However, volume density was decreased by 34.3% (immature dendritic cells) and 91% (mature dendritic cells) with respect to alveolar macrophages. These results show that human monocyte-derived immature dendritic cells possess a phagocytic capacity that is lower than that of peripheral blood monocytes and alveolar macrophages but higher than that of mature dendritic cells.
GITAHI DRKIAMASTEPHEN. "Kiama S. G., and P. Gehr (1999). Phagocytosis in dendritic cells.". In: Presented at the Division of Pneumology, Cantonal Hospital of Geneva, Geneva, Switzerland on 17th December 1999. Elsevier; 1999. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
Gitahi JN, M.M G, P.B. G, T.W. G, A N. "Multidrug resistant Escherichia coli isolated from asymptomatic school going children in kibera slum, Kenya." African Journal of Bacteriology Research. 2018;10(5):70-77.
GITAHI DRKIAMASTEPHEN. "Kiama S. G., J. Bhattacharjee, T. N. Kiama , D. K. Mwangi (2003). A Scanning electron microscope Study of Pigment Distribution in Pecten Oculi of the Domestic Fowl and Eagle Owl. The Kenya Veterinarian 26:43-50.". In: Faculty of Veterinary Medicine Biennial Scientific Conference, 3rd to 5th November 2004. Elsevier; 2003. Abstract
In structure-function relationship studies, stereological methods are applied to quantify structural qualities under investigation. In certain organs, like the brain, it is important to count the number of neurons associated with a particular function or region. The count gives an estimate of the electronic units available for a specific task or are endowed with a quantum of electrical energy. Similar studies can be extended in organs like the kidney, glands and muscles. Therefore, stereological methods enhance our knowledge of optimization of structure to funtion in biological design. This paper expounds on the methods used in estimation of number of particles in three-dimensional space. It articulates a historical perspective of the development of particle counting techniques to date in stereology showing how the problem was solved and a sound, practical and unbiased method developed. Two approaches are applied in counting particle number. The model based and the design based approach. The model-based approach assumes that the components under investigation are regular geometrical structures whose parameters can be quantified using regular geometrical methods. This counting method is biased, inefficient and difficult to apply in biological tissues. The design based approach applies a three dimensional sampling probe, the disector and makes no assumptions about shape or size of the components under investigation as in model approach.
GITAHI DRKIAMASTEPHEN. "Dreher D., Obregon C., Kok M., Kiama S.G., Gehr P., and L. P. Nicod(2001). Release of IL-18 by salmonella SipB protein in human antigenpresenting cells. Journal of Aerosol Medicine 14: P2-11.". In: Faculty of Veterinary Medicine Biennial Scientific Conference 2002. Elsevier; 2001. Abstract
Dendritic cells play a central role in initiation of primary T lymphocyte responses to foreign antigens. Their potency in antigen presentation vis-a-vis reported low or lack of ability to phagocytize particulate matter has limited our understanding of the role that they play in inducing immunity to particulate antigens. One hypothesis is that dendritic cells may possess a high phagocytic capacity when immature and located in peripheral tissues, which they lose on maturation. Our goal was to characterize the phagocytic capacity in human immature dendritic cells. The phagocytic capacity of human monocyte-derived immature dendritic cells was studied by morphological and morphometric means, and compared to that of professional phagocytes, human alveolar macrophages, their progenitors, the peripheral blood monocytes, and mature dendritic cells. Phagocytic index (proportion of phagocytic cells) was decreased by 42.8% (immature dendritic cells) and 74.2% (mature dendritic cells) with respect to monocytes. Similarly, the phagocytic index was decreased by 46.5% (immature dendritic cells) and 75.9% (mature dendritic cells) with respect to macrophages. Volume density of phagocytized particles was decreased by 76.1% (immature dendritic cells) and 96.7% (mature dendritic cells) with respect to the monocytes. However, volume density was decreased by 34.3% (immature dendritic cells) and 91% (mature dendritic cells) with respect to alveolar macrophages. These results show that human monocyte-derived immature dendritic cells possess a phagocytic capacity that is lower than that of peripheral blood monocytes and alveolar macrophages but higher than that of mature dendritic cells.
GITAHI DRKIAMASTEPHEN. "Kiama S. G. (2000). Phagocytosis of particulate antigens by human dendritic cells and its relevance in development of immunity.". In: Presented at the Institute of Anatomy,University of Bern, Bern,Switzerland on 8th June 2000. Elsevier; 2000. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
GITAHI DRKIAMASTEPHEN. "Mogoa E. G. M., Wabacha J. K., Mbithi P. M. F., Kiama S. G (2005).An overview of animal welfare issues in Kenya. The Kenya Veterinarian 29:48-52.". In: Faculty of Veterinary Medicine Biennial Scientific Conference and Exhibition, 6th to 8th September 2006. Elsevier; 2005.
GITAHI DRKIAMASTEPHEN. "Walter E., Dreher D., Kok M., Thiele L, Kiama S. G., Gehr P., and H.P. Merkle (2001). Hydrophilic poly (DL-lactide-co-glycolide) microspheres for the delivery of DNA to human-derived macrophages and dendritic cells. Journal of Controlled Release 76: 149-1.". In: Faculty of Veterinary Medicine Biennial Scientific Conference 2002. Elsevier; 2001. Abstract
Dendritic cells play a central role in initiation of primary T lymphocyte responses to foreign antigens. Their potency in antigen presentation vis-a-vis reported low or lack of ability to phagocytize particulate matter has limited our understanding of the role that they play in inducing immunity to particulate antigens. One hypothesis is that dendritic cells may possess a high phagocytic capacity when immature and located in peripheral tissues, which they lose on maturation. Our goal was to characterize the phagocytic capacity in human immature dendritic cells. The phagocytic capacity of human monocyte-derived immature dendritic cells was studied by morphological and morphometric means, and compared to that of professional phagocytes, human alveolar macrophages, their progenitors, the peripheral blood monocytes, and mature dendritic cells. Phagocytic index (proportion of phagocytic cells) was decreased by 42.8% (immature dendritic cells) and 74.2% (mature dendritic cells) with respect to monocytes. Similarly, the phagocytic index was decreased by 46.5% (immature dendritic cells) and 75.9% (mature dendritic cells) with respect to macrophages. Volume density of phagocytized particles was decreased by 76.1% (immature dendritic cells) and 96.7% (mature dendritic cells) with respect to the monocytes. However, volume density was decreased by 34.3% (immature dendritic cells) and 91% (mature dendritic cells) with respect to alveolar macrophages. These results show that human monocyte-derived immature dendritic cells possess a phagocytic capacity that is lower than that of peripheral blood monocytes and alveolar macrophages but higher than that of mature dendritic cells.
GITAHI DRKIAMASTEPHEN. "Dreher D., Kok M., Kiama S. G., Cochand L., Gehr P., and L. P. Nicod(2000). Apoptosis in dendritic cells: Consequences for immunotherapy with Salmonella vectors.". In: Presented at the fourth NFP37 Somatic Gene Therapy meeting held in Fribourg, Switzerland on 6th October 2000. Elsevier; 2000. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
GITAHI DRKIAMASTEPHEN. "Kiama, S. G., Bhattacharjee, J., Maina, J. N. and K. D. Weyrauch(1994). Scanning electron microscope study of the pecten oculi of the black kite (Milvus migrans): possible involvement of melanosomes in protecting the pecten against damage by ultraviolet l.". In: Presented at the . Elsevier; 1994. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
GITAHI DRKIAMASTEPHEN. "Kiama S. G., Dreher D., Cochand L., Kok M., Obregon C., Nicod L. P.,Gehr P. (2006). Host cell responces of Salmonella typhimurium infected human dendritic cells. Immunology and Cell Biology 84:475-481.". In: Journal of Anatomy 213:452-63. Elsevier; 2006. Abstract

Live attenuated Salmonella are attractive vaccine candidates for mucosal application because they induce both mucosal immune responses and systematic immune responses. After breaking the epithelium barrier, Salmonella typhimurium is found within dendritic cells (DC) in the Peyer's patches. Although there are abundant data on the interaction of S. typhimurium with murine epithelial cells, macrophages and DC, little is known about its interaction with human DC. Live attenuated S. typhimurium have recently been shown to efficiently infect human DC in vitro and induce production of cytokines. In this study, we have analysed the morphological consequences of infection of human DC by the attenuated S. typhimurium mutant strains designated PhoPc, AroA and SipB and the wild-type strains of the American Type Culture Collection (Manassas, VA, USA), ATCC 14028 and ATCC C53, by electron microscopy at 30 min, 3 h and 24 h after exposure. Our results show that genetic background of the strains profoundly influence DC morphology following infection. The changes included (i) membrane ruffling; (ii) formation of tight or spacious phagosomes; (iii) apoptosis; and (iv) spherical, pedunculated membrane-bound microvesicles that project from the plasma membrane. Despite the fact that membrane ruffling was much more pronounced with the two virulent strains, all mutants were taken up by the DC. The microvesicles were induced by all the attenuated strains, including SipB, which did not induce apoptosis in the host cell. These results suggest that Salmonella is internalized by human DC, inducing morphological changes in the DC that could explain immunogenicity of the attenuated strains.

GITAHI DRKIAMASTEPHEN. "Kiama S. G. (2001). Functional and Morphological Characterization of Particle .". In: Faculty of Veterinary Medicine Biennial Scientific Conference 2002. Elsevier; 2001. Abstract
Dendritic cells play a central role in initiation of primary T lymphocyte responses to foreign antigens. Their potency in antigen presentation vis-a-vis reported low or lack of ability to phagocytize particulate matter has limited our understanding of the role that they play in inducing immunity to particulate antigens. One hypothesis is that dendritic cells may possess a high phagocytic capacity when immature and located in peripheral tissues, which they lose on maturation. Our goal was to characterize the phagocytic capacity in human immature dendritic cells. The phagocytic capacity of human monocyte-derived immature dendritic cells was studied by morphological and morphometric means, and compared to that of professional phagocytes, human alveolar macrophages, their progenitors, the peripheral blood monocytes, and mature dendritic cells. Phagocytic index (proportion of phagocytic cells) was decreased by 42.8% (immature dendritic cells) and 74.2% (mature dendritic cells) with respect to monocytes. Similarly, the phagocytic index was decreased by 46.5% (immature dendritic cells) and 75.9% (mature dendritic cells) with respect to macrophages. Volume density of phagocytized particles was decreased by 76.1% (immature dendritic cells) and 96.7% (mature dendritic cells) with respect to the monocytes. However, volume density was decreased by 34.3% (immature dendritic cells) and 91% (mature dendritic cells) with respect to alveolar macrophages. These results show that human monocyte-derived immature dendritic cells possess a phagocytic capacity that is lower than that of peripheral blood monocytes and alveolar macrophages but higher than that of mature dendritic cells.
GITAHI DRKIAMASTEPHEN. "Kiama, S. G., Dreher D., L. Cochand, Kok M., Pechere J. C., Gehr P., and L. P Nicod (2000). Human Dendritic cells infected with Salmonella typhimurium produce iccosome-like structures. European Respiratory Journal 16: 178s.". In: Fifth NFP37 Somatic Gene Therapy meeting. Elsevier; 2000. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
GITAHI DRKIAMASTEPHEN. "Kiama, S. G., Bhattacharjee, J., Maina, J. N. and K. D. Weyrauch(1997). Surface specialisation of the capillary endothelium in the pecten oculi of the chicken, and their overt roles in pectineal haemodynamics and nutrient transfer to the inner neural reti.". In: Presented at the . Elsevier; 1997. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
GITAHI DRKIAMASTEPHEN. "Kiama, S. G., Maina, J. N., Bhattacharjee J., and K. D. Weyrauch (2001). Functional morphology of the pecten oculi in the nocturnal spotted eagle owl (Bubo bubo africanus), and the diurnal black kite (Milvus migrans) and the domestic fowl (Gallus gallus v.". In: Faculty of Veterinary Medicine Biennial Scientific Conference 2002. Elsevier; 2001. Abstract
Dendritic cells play a central role in initiation of primary T lymphocyte responses to foreign antigens. Their potency in antigen presentation vis-a-vis reported low or lack of ability to phagocytize particulate matter has limited our understanding of the role that they play in inducing immunity to particulate antigens. One hypothesis is that dendritic cells may possess a high phagocytic capacity when immature and located in peripheral tissues, which they lose on maturation. Our goal was to characterize the phagocytic capacity in human immature dendritic cells. The phagocytic capacity of human monocyte-derived immature dendritic cells was studied by morphological and morphometric means, and compared to that of professional phagocytes, human alveolar macrophages, their progenitors, the peripheral blood monocytes, and mature dendritic cells. Phagocytic index (proportion of phagocytic cells) was decreased by 42.8% (immature dendritic cells) and 74.2% (mature dendritic cells) with respect to monocytes. Similarly, the phagocytic index was decreased by 46.5% (immature dendritic cells) and 75.9% (mature dendritic cells) with respect to macrophages. Volume density of phagocytized particles was decreased by 76.1% (immature dendritic cells) and 96.7% (mature dendritic cells) with respect to the monocytes. However, volume density was decreased by 34.3% (immature dendritic cells) and 91% (mature dendritic cells) with respect to alveolar macrophages. These results show that human monocyte-derived immature dendritic cells possess a phagocytic capacity that is lower than that of peripheral blood monocytes and alveolar macrophages but higher than that of mature dendritic cells.
GITAHI DRKIAMASTEPHEN. "Kiama, S. G., Bhattacharjee, J., Maina, J. N., Weyrauch, K. D. and P. Gehr (1998). A scanning electron microscope study of the luminal surface specialisations in the blood vessels of the pecten oculi in a diurnal bird, the black kite (Milvus migrans). Ann.". In: Presented at the . Elsevier; 1998. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
GITAHI DRKIAMASTEPHEN. "Dreher, D., Kok M., C. Obregon, Kiama S. G., Gehr P., and L. P Nicod(2002). Salmonella virulence factor SipB induces activation and release of IL-18 in human dendritic cells. Journal of Leukocyte Biology 72:743-751.". In: Faculty of Veterinary Medicine Biennial Scientific Conference, 3rd to 5th November 2004. Elsevier; 2002. Abstract
Interleukin-18 (IL-18) plays an important role in innate and acquired immunity, in particular against intracellular pathogens. However, little is known about the microbial factors that trigger IL-18 secretion by dendritic cells (DCs). To determine the influence of bacterial virulence factors on the activation and release of IL-18, we infected human monocyte-derived DCs with virulence mutants of the facultative intracellular pathogen Salmonella typhimurium. Our results show that infection by S. typhimurium causes caspase-1-dependent activation of IL-18 and triggers the release of IL-18 in human DCs. The secretion of IL-18 by the DCs was closely correlated with the ability of the S. typhimurium strains to induce apoptosis. We demonstrate that activation and release of IL-18 are blocked by mutations in the Salmonella sipB gene, which encodes a virulence factor that activates caspase-1 to induce apoptosis. These findings indicate that the activation and release of IL-18 induced by bacterial virulence factors may represent one component of innate immunity against the intracellular bacteria.
GITAHI DRKIAMASTEPHEN. "Dreher D., Kok M., Imboden P., Kiama S. G., Muhindi, D.W., Georgopoulos C., and L. P. Nicod (2001). From genomics to vaccination: treatment of latent tuberculosis by recombinant salmonella.". In: Fifth NFP37 Somatic Gene Therapy meeting. Elsevier; 2001. Abstract
Dendritic cells play a central role in initiation of primary T lymphocyte responses to foreign antigens. Their potency in antigen presentation vis-a-vis reported low or lack of ability to phagocytize particulate matter has limited our understanding of the role that they play in inducing immunity to particulate antigens. One hypothesis is that dendritic cells may possess a high phagocytic capacity when immature and located in peripheral tissues, which they lose on maturation. Our goal was to characterize the phagocytic capacity in human immature dendritic cells. The phagocytic capacity of human monocyte-derived immature dendritic cells was studied by morphological and morphometric means, and compared to that of professional phagocytes, human alveolar macrophages, their progenitors, the peripheral blood monocytes, and mature dendritic cells. Phagocytic index (proportion of phagocytic cells) was decreased by 42.8% (immature dendritic cells) and 74.2% (mature dendritic cells) with respect to monocytes. Similarly, the phagocytic index was decreased by 46.5% (immature dendritic cells) and 75.9% (mature dendritic cells) with respect to macrophages. Volume density of phagocytized particles was decreased by 76.1% (immature dendritic cells) and 96.7% (mature dendritic cells) with respect to the monocytes. However, volume density was decreased by 34.3% (immature dendritic cells) and 91% (mature dendritic cells) with respect to alveolar macrophages. These results show that human monocyte-derived immature dendritic cells possess a phagocytic capacity that is lower than that of peripheral blood monocytes and alveolar macrophages but higher than that of mature dendritic cells.
GITAHI DRKIAMASTEPHEN. "Kiama, S. G., Cochand L., Nicod L. P., and P. Gehr (1999). Stereological assessment of phagocytosis by monocytes, alveolar macrophages and dendritic cells.". In: Presented at the 12th Biennial Congress. International Society for Aerosols in Medicine held in Vienna, Austria on 12th to 16th June 1999). Elsevier; 1999. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
GITAHI DRKIAMASTEPHEN. "Kiama S. G., J. Bhattacharjee, T. N. Kiama , D. K. Mwangi (2003). A Scanning electron microscope Study of Pigment Distribution in Pecten Oculi of the Domestic Fowl and Eagle Owl. The Kenya Veterinarian 26:43-50.". In: Faculty of Veterinary Medicine Biennial Scientific Conference, 3rd to 5th November 2004. Elsevier; 2003. Abstract
In structure-function relationship studies, stereological methods are applied to quantify structural qualities under investigation. In certain organs, like the brain, it is important to count the number of neurons associated with a particular function or region. The count gives an estimate of the electronic units available for a specific task or are endowed with a quantum of electrical energy. Similar studies can be extended in organs like the kidney, glands and muscles. Therefore, stereological methods enhance our knowledge of optimization of structure to funtion in biological design. This paper expounds on the methods used in estimation of number of particles in three-dimensional space. It articulates a historical perspective of the development of particle counting techniques to date in stereology showing how the problem was solved and a sound, practical and unbiased method developed. Two approaches are applied in counting particle number. The model based and the design based approach. The model-based approach assumes that the components under investigation are regular geometrical structures whose parameters can be quantified using regular geometrical methods. This counting method is biased, inefficient and difficult to apply in biological tissues. The design based approach applies a three dimensional sampling probe, the disector and makes no assumptions about shape or size of the components under investigation as in model approach.
GITAHI DRKIAMASTEPHEN. "Kiama, S. G., Dreher D., Cochand L., Kok M., Pechere J. C., Nicod L. P.,and P. Gehr (2001). Interaction of Salmonella with human dendritic cells: Production of iccosome-like structures with potential role in antigen presentation.". In: Keystone Symposia on . Elsevier; 2001. Abstract
Dendritic cells play a central role in initiation of primary T lymphocyte responses to foreign antigens. Their potency in antigen presentation vis-a-vis reported low or lack of ability to phagocytize particulate matter has limited our understanding of the role that they play in inducing immunity to particulate antigens. One hypothesis is that dendritic cells may possess a high phagocytic capacity when immature and located in peripheral tissues, which they lose on maturation. Our goal was to characterize the phagocytic capacity in human immature dendritic cells. The phagocytic capacity of human monocyte-derived immature dendritic cells was studied by morphological and morphometric means, and compared to that of professional phagocytes, human alveolar macrophages, their progenitors, the peripheral blood monocytes, and mature dendritic cells. Phagocytic index (proportion of phagocytic cells) was decreased by 42.8% (immature dendritic cells) and 74.2% (mature dendritic cells) with respect to monocytes. Similarly, the phagocytic index was decreased by 46.5% (immature dendritic cells) and 75.9% (mature dendritic cells) with respect to macrophages. Volume density of phagocytized particles was decreased by 76.1% (immature dendritic cells) and 96.7% (mature dendritic cells) with respect to the monocytes. However, volume density was decreased by 34.3% (immature dendritic cells) and 91% (mature dendritic cells) with respect to alveolar macrophages. These results show that human monocyte-derived immature dendritic cells possess a phagocytic capacity that is lower than that of peripheral blood monocytes and alveolar macrophages but higher than that of mature dendritic cells.
GITAHI DRKIAMASTEPHEN. "Kiama, S. G., Cochand L., Nicod L. P., and P. Gehr (1999). Stereological assessment of phagocytosis by monocytes, alveolar macrophages and dendritic cells. Journal of Aerosol Medicine 12 (2): 49.". In: Presented at the Institute of Anatomy,University of Bern, Bern,Switzerland on 8th June 2000. Elsevier; 1999. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
Gitahi MG, Wangoh J, Njage PMK. "Microbial Safety of Street Food in Industrial Area, Nairobi.". 2012. Abstract

Street food play a significant role in feeding urban population with cheap accessible and nutritious foods. Most street foods vendors are not trained on food hygiene and safety........

Gitahi N, Gicheru MM, Gathura PB, Karanja NK, Githinji WT, Nordin A. "Internalization of enteropathogenic human bacteria in lettuce and coriander plant tissue." ISABB Journal of Health and Environmental Sciences. 2018;Vol. 5(3): 28-32.
GITAHI DRKIAMASTEPHEN. "Mwangi D. K., Kiama S. G. (2005). Stereological methods for estimation of total number of particles in an organ. The Kenya Veterinarian 29: 33-36.". In: Faculty of Veterinary Medicine Biennial Scientific Conference and Exhibition, 6th to 8th September 2006. Elsevier; 2005.
GITAHI DRKIAMASTEPHEN. "Kiama, S. G., Dreher D., Cochand L., Kok M., Pechere J. C., Gehr P., and L. P Nicod (2001). Mutants of Salmonella typhimurium infect human dendritic cells and induce formation of iccosome-like structures.American Journal of Respiratory and Critical Care M.". In: Faculty of Veterinary Medicine Biennial Scientific Conference 2002. Elsevier; 2001. Abstract
Dendritic cells play a central role in initiation of primary T lymphocyte responses to foreign antigens. Their potency in antigen presentation vis-a-vis reported low or lack of ability to phagocytize particulate matter has limited our understanding of the role that they play in inducing immunity to particulate antigens. One hypothesis is that dendritic cells may possess a high phagocytic capacity when immature and located in peripheral tissues, which they lose on maturation. Our goal was to characterize the phagocytic capacity in human immature dendritic cells. The phagocytic capacity of human monocyte-derived immature dendritic cells was studied by morphological and morphometric means, and compared to that of professional phagocytes, human alveolar macrophages, their progenitors, the peripheral blood monocytes, and mature dendritic cells. Phagocytic index (proportion of phagocytic cells) was decreased by 42.8% (immature dendritic cells) and 74.2% (mature dendritic cells) with respect to monocytes. Similarly, the phagocytic index was decreased by 46.5% (immature dendritic cells) and 75.9% (mature dendritic cells) with respect to macrophages. Volume density of phagocytized particles was decreased by 76.1% (immature dendritic cells) and 96.7% (mature dendritic cells) with respect to the monocytes. However, volume density was decreased by 34.3% (immature dendritic cells) and 91% (mature dendritic cells) with respect to alveolar macrophages. These results show that human monocyte-derived immature dendritic cells possess a phagocytic capacity that is lower than that of peripheral blood monocytes and alveolar macrophages but higher than that of mature dendritic cells.
GITAHI DRKIAMASTEPHEN. "Walter E., Dreher, D., Kok M., Thiele L., Kiama S. G., Gehr P., and P. Merkle (2000). Interaction between DNA-loaded poly (DL-lactide-coglycolide)microspheres and human antigen-presenting cells Pharmaceutical Research.". In: Presented at the fourth NFP37 Somatic Gene Therapy meeting held in Fribourg, Switzerland on 6th October 2000. Elsevier; 2000. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
GITAHI DRKIAMASTEPHEN. "Bhattacharjee, J., Kiama, S. G., and J. N. Maina (1994). Fine structure of the pecten oculi of the spotted eagle owl with special reference to the surface distribution of melanosomes. Experimental Eye Research 59,S1, 114.". In: Presented at the . Elsevier; 1994. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
GITAHI DRKIAMASTEPHEN. "Kiama S. G. (2006). Evolving trends in veterinary education. .". In: Faculty of Veterinary Medicine Biennial Scientific Conference and Exhibition, 6th to 8th September 2006. Elsevier; 2006. Abstract
Formal veterinary education began in the Western world in the 1763 in Lyon, 1767 in Vienna and 1791 in London. These institutions were established in an effort to reduce the severe economic impact of animal diseases, particularly, rinderpest. However over time the profession has evolved in line with emerging issues such as animal welfare, food safety, the environment and advancement in information computer technology. Furthermore, consumers and clients are increasingly well informed, and the professionals no longer have a monopoly of knowledge in their area. Moreover, the hitherto assumption that an initial degree would confers one unlimited, life-long license to practice without any need for continuing education is being questioned. Furthermore, there is continued pressure on university resources, as well as problems in attracting competent clinical staff to teach in areas of specialization and, the universities are being expected to achieve more and more with fewer resources. The structure of the profession is also gradually changing with a move towards more specialist practices, but with mixed practice still an important employer of veterinary surgeons in rural areas. In addition, there is growing awareness that the amount of veterinary knowledge is expanding all the time and it is not possible anymore, for undergraduates to achieve high levels of expertise in all areas of the veterinary profession during the 4 to 6 years available for training. These issues have continued to model the evolution of the veterinary education. The evolution has mainly focused on 6 main areas namely, review on admission criteria and curriculum review, adoption of new teaching methods, collaboration with private clinicians, introduction of apprenticeship and mandatory continuing veterinary education. This paper will elaborate on the evolving trends in veterinary education as defined by each of
GITAHI DRKIAMASTEPHEN. "Kiama, S. G., Cochand L., Karlsson L. M., Nicod L. P., and P. Gehr(2001). Evaluation of phagocytic activity in human monocytederived dendritic cells. Journal of Aerosol Medicine 14: 289-299.". In: Faculty of Veterinary Medicine Biennial Scientific Conference 2002. Elsevier; 2001. Abstract
Dendritic cells play a central role in initiation of primary T lymphocyte responses to foreign antigens. Their potency in antigen presentation vis-a-vis reported low or lack of ability to phagocytize particulate matter has limited our understanding of the role that they play in inducing immunity to particulate antigens. One hypothesis is that dendritic cells may possess a high phagocytic capacity when immature and located in peripheral tissues, which they lose on maturation. Our goal was to characterize the phagocytic capacity in human immature dendritic cells. The phagocytic capacity of human monocyte-derived immature dendritic cells was studied by morphological and morphometric means, and compared to that of professional phagocytes, human alveolar macrophages, their progenitors, the peripheral blood monocytes, and mature dendritic cells. Phagocytic index (proportion of phagocytic cells) was decreased by 42.8% (immature dendritic cells) and 74.2% (mature dendritic cells) with respect to monocytes. Similarly, the phagocytic index was decreased by 46.5% (immature dendritic cells) and 75.9% (mature dendritic cells) with respect to macrophages. Volume density of phagocytized particles was decreased by 76.1% (immature dendritic cells) and 96.7% (mature dendritic cells) with respect to the monocytes. However, volume density was decreased by 34.3% (immature dendritic cells) and 91% (mature dendritic cells) with respect to alveolar macrophages. These results show that human monocyte-derived immature dendritic cells possess a phagocytic capacity that is lower than that of peripheral blood monocytes and alveolar macrophages but higher than that of mature dendritic cells.
GITAHI DRKIAMASTEPHEN. "Bhattacharjee J., and S. G. Kiama (2000). Distribution of melanocytes in the pecten oculi of diurnal domestic fowl and nocturnal spotted eagle owl. Experimental Eye Research Vol. 71, Supplement 1, p205.". In: Fifth NFP37 Somatic Gene Therapy meeting. Elsevier; 2000. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
GITAHI DRKIAMASTEPHEN. "Kiama S. G. (1995). Morphology and Morphometry of the Pecten Oculi: A Comparative Study. Masters of Science in Veterinary Anatomy, University of Nairobi, Kenya.". In: Presented at the . Elsevier; 1995. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
GITAHI DRKIAMASTEPHEN. "Kiama S. G., Maina J. N., Bhattacharjee J., Mwangi D. K., Macharia R. G., Weyrauch K. D. (2006). The Morphology of the pectin oculi of the ostrich, Struthio camelus. Annals of Anatomy 188:516-528.". In: Journal of Anatomy 213:452-63. Elsevier; 2006. Abstract
The pecten oculi is a structure peculiar to the avian eye. Three morphological types of pecten oculi are recognized: conical type, vaned type and pleated type. The pleated type has been well studied. However, there exists only scanty data on the morphology of the latter two types of pectens. The structure of the vaned type of pecten of the ostrich, Struthio camelus was investigated with light and electron microscope. The pecten of this species consists of a vertical primary lamella that arises from the optic disc and supports 16-19 laterally located secondary lamellae, which run from the base and confluence at the apex. Some of the secondary lamellae give rise to 2 or 3 tertiary lamellae. The lamellae provide a wide surface, which supports 2-3 Layers of blood capillaries. Pigmentation is highest at the distal ends of the secondary and tertiary Lamella where blood capillaries are concentrated and very scanty on the primary and the proximal ends of the secondary lamella where the presence of capillaries is much reduced. In contrast to the capillaries of the pleated pecten, the endothelium of the capillaries in the pecten of the ostrich exhibits very few microvilli. These observations suggest that the morphology of the pecten of the ostrich, a flightless ratite bird is unique to the pleated pecten and is designed to meet the balance between optimal vision and large surface area for blood supply and yet ensuring it is kept firmly erect within the vitreous.
GITAHI DRKIAMASTEPHEN. "Dreher, D., Cochand L., Kok M., Kiama S. G., Gehr P., Pech.". In: Faculty of Veterinary Medicine Biennial Scientific Conference 2002. Elsevier; 2001. Abstract
Dendritic cells play a central role in initiation of primary T lymphocyte responses to foreign antigens. Their potency in antigen presentation vis-a-vis reported low or lack of ability to phagocytize particulate matter has limited our understanding of the role that they play in inducing immunity to particulate antigens. One hypothesis is that dendritic cells may possess a high phagocytic capacity when immature and located in peripheral tissues, which they lose on maturation. Our goal was to characterize the phagocytic capacity in human immature dendritic cells. The phagocytic capacity of human monocyte-derived immature dendritic cells was studied by morphological and morphometric means, and compared to that of professional phagocytes, human alveolar macrophages, their progenitors, the peripheral blood monocytes, and mature dendritic cells. Phagocytic index (proportion of phagocytic cells) was decreased by 42.8% (immature dendritic cells) and 74.2% (mature dendritic cells) with respect to monocytes. Similarly, the phagocytic index was decreased by 46.5% (immature dendritic cells) and 75.9% (mature dendritic cells) with respect to macrophages. Volume density of phagocytized particles was decreased by 76.1% (immature dendritic cells) and 96.7% (mature dendritic cells) with respect to the monocytes. However, volume density was decreased by 34.3% (immature dendritic cells) and 91% (mature dendritic cells) with respect to alveolar macrophages. These results show that human monocyte-derived immature dendritic cells possess a phagocytic capacity that is lower than that of peripheral blood monocytes and alveolar macrophages but higher than that of mature dendritic cells.
GITAHI DRKIAMASTEPHEN. "Kiama, S. G., Bhattacharjee, J., Maina, J. N., Weyrauch, K. D. and P.Gehr (1998). A scanning electron microscope study of the luminal surface specialisations in the blood vessels of the pecten oculi in a diurnal bird, the black kite (Milvus migrans). Anna.". In: Presented at the . Elsevier; 1998. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
GITAHI DRKIAMASTEPHEN. "Kiama S. G., D. Dreher M. Kok L. Cochand L. P. Nicod P. Gehr (2002) Live bacterial vectors for mucosal delivery of protective antigen. Targeting of mucosal dendritic cells.". In: Faculty of Veterinary Medicine Biennial Scientific Conference 2002. Elsevier; 2002. Abstract
Interleukin-18 (IL-18) plays an important role in innate and acquired immunity, in particular against intracellular pathogens. However, little is known about the microbial factors that trigger IL-18 secretion by dendritic cells (DCs). To determine the influence of bacterial virulence factors on the activation and release of IL-18, we infected human monocyte-derived DCs with virulence mutants of the facultative intracellular pathogen Salmonella typhimurium. Our results show that infection by S. typhimurium causes caspase-1-dependent activation of IL-18 and triggers the release of IL-18 in human DCs. The secretion of IL-18 by the DCs was closely correlated with the ability of the S. typhimurium strains to induce apoptosis. We demonstrate that activation and release of IL-18 are blocked by mutations in the Salmonella sipB gene, which encodes a virulence factor that activates caspase-1 to induce apoptosis. These findings indicate that the activation and release of IL-18 induced by bacterial virulence factors may represent one component of innate immunity against the intracellular bacteria.
GITAHI DRKIAMASTEPHEN. "Dreher D., Cochand L., Kok M., Pechere J. C., Kiama S.G., Gehr P., and L. P. Nicod (2000). Genetic background of Salmonella typhimurium vaccine strains has profound influence on infectivity and cytokine production in human dendritic cells. Schweiz. Med. W.". In: Fifth NFP37 Somatic Gene Therapy meeting. Elsevier; 2000. Abstract
Salmonella typhimurium (ST) can cause infection in man, and attenuated strains are under consideration as live vaccine vectors. However, little is known about the interaction of ST with human dendritic cells (DC). Here, we compared the consequences of exposure of human, monocyte-derived DC with different attenuated strains of ST. Infection was observed with all four strains tested (wild type, PhoP-, PhoPc, and AroA), but the PhoPc strain was by far the most efficient. Intracellular persistence of wild type and PhoP- was longer than that of PhoPc and AroA, both of which were largely eliminated within 24 h. Most DC survived infection by the attenuated strains, although apoptosis was observed in a fraction of the exposed cells. All strains induced DC maturation, independent from the extent of infection. Although all strains stimulated secretion of TNF-alpha and IL-12 strongly, PhoPc induced significantly less IL-10 than the other three strains and as much as 10 times less IL-10 than heat-killed PhoPc, suggesting that this mutant suppressed the secretion of IL-10 by the DC. These data indicate that infectivity, bacterial elimination, and cytokine secretion in human DC are controlled by the genetic background of ST.
GITAHI DRKIAMASTEPHEN. "Kiama, S. G., Cochand L., Nicod L. P., and P. Gehr (1999). Stereological assessment of phagocytosis by dendritic cells.". In: Presented at the 31st Curriculum Vitae Kiama S G, December 2006 Annual meeting of USGEB held in Basel Switzerland on October 14-15,1999. Elsevier; 1999. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
GITAHI DRKIAMASTEPHEN. "Obregon C., Dreher, D., Kok M., Cochand L., Kiama S. G., and L. P Nicod (2003). Human alveolar macrophages infected by virulent bacterial expressing SipB are a major source of Active interleukin-18. Infection and Immunity 71: 4382-4388.". In: Faculty of Veterinary Medicine Biennial Scientific Conference, 3rd to 5th November 2004. Elsevier; 2003. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
GITAHI DRKIAMASTEPHEN. "Kiama S. G. (2001). Human dendritic cells. .". In: Presented at the Department of Human Anatomy, University of Nairobi, Kenya on 22nd August 2001. Elsevier; 2001. Abstract
Dendritic cells play a central role in initiation of primary T lymphocyte responses to foreign antigens. Their potency in antigen presentation vis-a-vis reported low or lack of ability to phagocytize particulate matter has limited our understanding of the role that they play in inducing immunity to particulate antigens. One hypothesis is that dendritic cells may possess a high phagocytic capacity when immature and located in peripheral tissues, which they lose on maturation. Our goal was to characterize the phagocytic capacity in human immature dendritic cells. The phagocytic capacity of human monocyte-derived immature dendritic cells was studied by morphological and morphometric means, and compared to that of professional phagocytes, human alveolar macrophages, their progenitors, the peripheral blood monocytes, and mature dendritic cells. Phagocytic index (proportion of phagocytic cells) was decreased by 42.8% (immature dendritic cells) and 74.2% (mature dendritic cells) with respect to monocytes. Similarly, the phagocytic index was decreased by 46.5% (immature dendritic cells) and 75.9% (mature dendritic cells) with respect to macrophages. Volume density of phagocytized particles was decreased by 76.1% (immature dendritic cells) and 96.7% (mature dendritic cells) with respect to the monocytes. However, volume density was decreased by 34.3% (immature dendritic cells) and 91% (mature dendritic cells) with respect to alveolar macrophages. These results show that human monocyte-derived immature dendritic cells possess a phagocytic capacity that is lower than that of peripheral blood monocytes and alveolar macrophages but higher than that of mature dendritic cells.
GITAHI DRKIAMASTEPHEN. "Kiama, S. G., Bhattacharjee, J., Maina, J. N., Weyrauch, K. D. and P.Gehr (1999). Comparative morphometry of the pecten oculi in domestic fowl (Gallus domesticus), black kite (Milvus migrans) and spotted eagle owl (Bubo africanus).". In: Presented at the Swiss Society for Anatomie, Histology and Embryology (SGAHE) held in Basel, Switzerland on 13th October 1999. Elsevier; 1999. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
GITAHI DRKIAMASTEPHEN. "Kiama S. G., J. N. Maina, K. D. Weyrauch, D. K. Mwangi (2004). The morphology of the pecten oculi of the ostrich, Struthio camelus.". In: Faculty of Veterinary Medicine Biennial Scientific Conference, 3rd to 5th November 2004. Elsevier; 2004. Abstract
The pecten oculi is a structure peculiar to the avian eye. Three morphological types of pecten oculi are recognized: conical type, vaned type and pleated type. The pleated type has been well studied. However, there exists only scanty data on the morphology of the latter two types of pectens. The structure of the vaned type of pecten of the ostrich, Struthio camelus was investigated with light and electron microscope. The pecten of this species consists of a vertical primary lamella that arises from the optic disc and supports 16-19 laterally located secondary lamellae, which run from the base and confluence at the apex. Some of the secondary lamellae give rise to 2 or 3 tertiary lamellae. The lamellae provide a wide surface, which supports 2-3 Layers of blood capillaries. Pigmentation is highest at the distal ends of the secondary and tertiary Lamella where blood capillaries are concentrated and very scanty on the primary and the proximal ends of the secondary lamella where the presence of capillaries is much reduced. In contrast to the capillaries of the pleated pecten, the endothelium of the capillaries in the pecten of the ostrich exhibits very few microvilli. These observations suggest that the morphology of the pecten of the ostrich, a flightless ratite bird is unique to the pleated pecten and is designed to meet the balance between optimal vision and large surface area for blood supply and yet ensuring it is kept firmly erect within the vitreous
GITAHI DRKIAMASTEPHEN. "Kiama, S. G., Dreher D., Cochand L., Kok M., Pechere J. C., L. P. Nicod and P. Gehr (2001). Candidate vaccine strains of Salmonella infect and induce profound changes in the morphology of human dendritic cells.Journal of Aerosol Medicine 14: P2-10.". In: Faculty of Veterinary Medicine Biennial Scientific Conference 2002. Elsevier; 2001. Abstract
Dendritic cells play a central role in initiation of primary T lymphocyte responses to foreign antigens. Their potency in antigen presentation vis-a-vis reported low or lack of ability to phagocytize particulate matter has limited our understanding of the role that they play in inducing immunity to particulate antigens. One hypothesis is that dendritic cells may possess a high phagocytic capacity when immature and located in peripheral tissues, which they lose on maturation. Our goal was to characterize the phagocytic capacity in human immature dendritic cells. The phagocytic capacity of human monocyte-derived immature dendritic cells was studied by morphological and morphometric means, and compared to that of professional phagocytes, human alveolar macrophages, their progenitors, the peripheral blood monocytes, and mature dendritic cells. Phagocytic index (proportion of phagocytic cells) was decreased by 42.8% (immature dendritic cells) and 74.2% (mature dendritic cells) with respect to monocytes. Similarly, the phagocytic index was decreased by 46.5% (immature dendritic cells) and 75.9% (mature dendritic cells) with respect to macrophages. Volume density of phagocytized particles was decreased by 76.1% (immature dendritic cells) and 96.7% (mature dendritic cells) with respect to the monocytes. However, volume density was decreased by 34.3% (immature dendritic cells) and 91% (mature dendritic cells) with respect to alveolar macrophages. These results show that human monocyte-derived immature dendritic cells possess a phagocytic capacity that is lower than that of peripheral blood monocytes and alveolar macrophages but higher than that of mature dendritic cells.
Gitahi MG, Wangoh J, Njage PMK. "Microbial Safety of Street Food in Industrial Area, Nairobi." Research Journal of Microbiology. 2012.2012-microbial_safety_of_steet_foods.pdf
GITAHI DRKIAMASTEPHEN. "Kiama S. G., and P. Gehr (2000). Dendritic cells-Particle interaction.". In: Presented at the DKF Research Conference, University of Bern,Switzerland Bern, Switzerland on 14th June 2000. Elsevier; 2000. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
GITAHI DRKIAMASTEPHEN. "Rothen-Rutishauser B. M., Kiama S. G., Gehr P. (2005). A three-dimensional cellular model of the human respiratory tract to study the interaction with particles. American Journal of Respiratory Cell and Molecular Biology 32:281-9.". In: Faculty of Veterinary Medicine Biennial Scientific Conference and Exhibition, 6th to 8th September 2006. Elsevier; 2005. Abstract
A novel triple co-culture model of the human airway barrier was designed to simulate the cellular part of the air-blood barrier of the respiratory tract represented by macrophages, epithelial cells, and dendritic cells. When epithelial cells (A549 cells) were grown on filter inserts with pores of 3.0 mum in diameter in a two-chamber system, they formed monolayers with polarization into apical and basolateral domains. The epithelial cell cultures were then supplemented with human blood monocyte-derived macrophages and dendritic cells on the apical and basal aspect, respectively. The single-cell cultures as well as the triple co-cultures were characterized in terms of a number of typical features, for example, morphology of cell types, integrity of epithelial layer, and expression of specific cell surface markers (CD14 for macrophages and CD86 for dendritic cells). The interplay of epithelial cells with macrophages and dendritic cells during the uptake of polystyrene particles (1 mum in diameter) was investigated with confocal laser scanning and conventional transmission electron microscopy. Particles were found in all three cell types, although dendritic cells were not directly exposed to the particles. More investigations are needed to understand the translocation pathway.
GITAHI DRKIAMASTEPHEN. "Kiama, S. G., Maina, J. N., Bhattacharjee J., and K. D. Weyrauch(2001). Functional morphology of the pecten oculi in the nocturnal spotted eagle owl (Bubo bubo africanus), and the diurnal black kite (Milvus migrans) and the domestic fowl (Gallus gallus va.". In: Faculty of Veterinary Medicine Biennial Scientific Conference 2002. Elsevier; 2001. Abstract
Dendritic cells play a central role in initiation of primary T lymphocyte responses to foreign antigens. Their potency in antigen presentation vis-a-vis reported low or lack of ability to phagocytize particulate matter has limited our understanding of the role that they play in inducing immunity to particulate antigens. One hypothesis is that dendritic cells may possess a high phagocytic capacity when immature and located in peripheral tissues, which they lose on maturation. Our goal was to characterize the phagocytic capacity in human immature dendritic cells. The phagocytic capacity of human monocyte-derived immature dendritic cells was studied by morphological and morphometric means, and compared to that of professional phagocytes, human alveolar macrophages, their progenitors, the peripheral blood monocytes, and mature dendritic cells. Phagocytic index (proportion of phagocytic cells) was decreased by 42.8% (immature dendritic cells) and 74.2% (mature dendritic cells) with respect to monocytes. Similarly, the phagocytic index was decreased by 46.5% (immature dendritic cells) and 75.9% (mature dendritic cells) with respect to macrophages. Volume density of phagocytized particles was decreased by 76.1% (immature dendritic cells) and 96.7% (mature dendritic cells) with respect to the monocytes. However, volume density was decreased by 34.3% (immature dendritic cells) and 91% (mature dendritic cells) with respect to alveolar macrophages. These results show that human monocyte-derived immature dendritic cells possess a phagocytic capacity that is lower than that of peripheral blood monocytes and alveolar macrophages but higher than that of mature dendritic cells.
GITAHI DRKIAMASTEPHEN. "Kiama, S. G., Dreher D., Cochand L., Kok M., Pechere J. C., Nicod L. P.,and P. Gehr (2000). Infection of human dendritic cells by Salmonella typhimurium.". In: Presented at the SGAHE 2000 held in Bern, Switzerland on 13th October 2000. Elsevier; 2000. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
GITAHI DRKIAMASTEPHEN. "Kiama, S. G., Bhattacharjee, J., Maina, J. N. and K. D. Weyrauch (1994). Scanning electron microscope study of the pecten oculi of the black kite (Milvus migrans): possible involvement of melanosomes in protecting the pecten against damage by ultraviolet .". In: Presented at the . Elsevier; 1994. Abstract
Recent publications have demonstrated that the protease caspase-1 is responsible for the processing of pro-interleukin 18 (IL-18) into the active form. Studies on cell lines and murine macrophages have shown that the bacterial invasion factor SipB activates caspase-1, triggering cell death. Thus, we investigated the role of SipB in the activation and release of IL-18 in human alveolar macrophages (AM), which are the first line of defense against inhaled pathogens. Under steady-state conditions, AM are a more important source of IL-18 than are dendritic cells (DC) and monocytes. Cytokine production by AM and DC was compared after both types of cells had been infected with a virulent strain of Salmonella enterica serovar Typhimurium and an isogenic sipB mutant, which were used as an infection model. Infection with virulent Salmonella led to marked cell death with features of apoptosis while both intracellular activation and release of IL-18 were demonstrated. In contrast, the sipB mutant did not induce such cell death or the release of active IL-18. The specific caspase-1 inhibitor Ac-YVAD-CMK blocked the early IL-18 release in AM infected with the virulent strain. However, the type of Salmonella infection did not differentially regulate IL-18 gene expression. We concluded that the bacterial virulence factor SipB plays an essential posttranslational role in the intracellular activation of IL-18 and the release of the cytokine in human AM.
GITAHI DRKIAMASTEPHEN. "Obregon C., Rothen-Rutishauser B., Kiama S.G., Gehr P., Nicod L. P.(2006). Exovesicles from human activated dendritic cells (DCS) fuse with resting DCS allowing them to present allo-antigens.American Journal of Pathology 169:2127-2136.". In: Journal of Anatomy 213:452-63. Elsevier; 2006. Abstract

Dendritic cells (DCs) can release microvesicles, but the latter's numbers, size, and fate are unclear. Fluorescently labeled DCs were visualized by laser-scanning microscopy. Using a Surpass algorithm, we were able to identify and quantify per cell several hundred microvesicles released from the surface of stimulated DCs. We show that most of these microvesicles are not of endocytic origin but result from budding of the plasma membrane, hence their name, exovesicle. Using a double vital staining, we show that exovesicles isolated from activated DCs can fuse with the membrane of resting DCs, thereby allowing them to present alloantigens to lymphocytes. We concluded that, within a few hours from their release, exovesicles may amplify local or distant adaptive immunological response.

GITAHI DRKIAMASTEPHEN. "Walter E., Dreher D., Kok M., Thiele L, Kiama S. G., Gehr P., and H. P. Merkle (2001). Hydrophilic poly (DL-lactide-co-glycolide) microspheres for the delivery of DNA to human-derived macrophages and dendritic cells. Journal of Controlled Release 76: 149-.". In: Faculty of Veterinary Medicine Biennial Scientific Conference 2002. Elsevier; 2001. Abstract
Dendritic cells play a central role in initiation of primary T lymphocyte responses to foreign antigens. Their potency in antigen presentation vis-a-vis reported low or lack of ability to phagocytize particulate matter has limited our understanding of the role that they play in inducing immunity to particulate antigens. One hypothesis is that dendritic cells may possess a high phagocytic capacity when immature and located in peripheral tissues, which they lose on maturation. Our goal was to characterize the phagocytic capacity in human immature dendritic cells. The phagocytic capacity of human monocyte-derived immature dendritic cells was studied by morphological and morphometric means, and compared to that of professional phagocytes, human alveolar macrophages, their progenitors, the peripheral blood monocytes, and mature dendritic cells. Phagocytic index (proportion of phagocytic cells) was decreased by 42.8% (immature dendritic cells) and 74.2% (mature dendritic cells) with respect to monocytes. Similarly, the phagocytic index was decreased by 46.5% (immature dendritic cells) and 75.9% (mature dendritic cells) with respect to macrophages. Volume density of phagocytized particles was decreased by 76.1% (immature dendritic cells) and 96.7% (mature dendritic cells) with respect to the monocytes. However, volume density was decreased by 34.3% (immature dendritic cells) and 91% (mature dendritic cells) with respect to alveolar macrophages. These results show that human monocyte-derived immature dendritic cells possess a phagocytic capacity that is lower than that of peripheral blood monocytes and alveolar macrophages but higher than that of mature dendritic cells.
Gitao CG, Kihu SM, Muse AE. Comparison of Peste des petits ruminants in Kenya and Tanzania.. in Nairobi Jacaranda Hotel, Westlands Nairobi-Kenya 9th – 10th June: FAO-EU ; 2015.comparison_of_peste_des_petits_ruminants_ppr.pptx
Gitao, C.G. "PhD supervision at University of Nairobi.". In: Carta Supervision workshop. Johannesburg, South Africa; 2018.
Gitao C, Wanjohi G, Bebora L, Muchemi, L. "Camel Milk Quality and Bacterial Contamination along Market Chain in Wajir and Garissa Counties of Kenya." Journal of Veterinary Medicine and Animal Health. 2017;4(10):1114.
Gitao, C.G. Reviewer, Transboundary and Emerging diseases. Trsansboundary and Emerging Diseases; 2020.tbed_reviewer_certificate_1_1.pdf
Gitao CG, Kihu SM, Bebora LC, Njenga JM, Wairire GG, Maingi N, Muse E, E K, Misinzo G, Mellau LSB, Msoffe PLM, Swai ES, Albano. "Comparison of Peste des petits ruminants (PPR) disease between Tanzania and Kenya.". In: Third Ruforum Biennial Meeting. Kampala, Uganda; 2012.gitao_523_3.pdf

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