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Thidiazuron (TDZ) effectively induced somatic embryogenesis in cultured hypocotyl explants of geranium (Pelargonium x hortorum Bailey) during only a 3-day period of induction. The presence of acetylsalicylic acid (ASA) during this period caused a two-fold increase in the number of somatic embryos and enhanced synchronization of embryo development compared to the TDZ treatment alone. Salicylic acid was ineffective in modulating similar embryogenic responses as ASA. The ASA-induced enhancement and synchronization of somatic embryogenesis could possibly be used as an experimental system to study the interplay of growth regulators in somatic embryogenesis

Clefts of the lip and palate (CLP) are amongst the commonest craniofacial anomalies
encountered by clinicians. Compared to many other anomalies, CLP is easily diagnosed
and described. Due to this, it has been one of the most intensively studied congenital
malformation worldwide. Anomalies of the face give rise to considerable morbidity
which is psychologically traumatic to the parents. Thus the need to study the oral health
status of children with cleft lip/palate (CLP) in a section of a Kenyan population.
Type of study: A descriptive comparative cross-sectional study.
Methods: A total of 89 children were clinically examined, 49 formed the study group
(children with clefts) and 40 were the control group (children without clefts) ; age range,
2 to 15 years. Factors such as plaque, gingivitis, caries, missing teeth and stage of the
dentition were recorded.
Setting: Nairobi, Kenya.
Results: Out of the 49 children in the study group, 55% had CLP and 33% had CLA
while 6%had isolated CL. The prevalence of plaque was 96.27% in the 'study group while
among the control group this was lower at 89.5% (p<0.05). This was reflected by the
significant difference observed in the frequency of tooth brushing (x211.564 l df
p=O.OOI). Children with clefts had a significantly increased number of units with
gingivitis ranging from 79.2% for tooth 16 (p=0.04) to 51.6% for tooth 52 (p =0.264),
although not statistically significant in the latter.
The prevalence of caries in the study group was 11.8% (95% CI; 9.8%-13.8%) and the
control group was 8% (95% CI; 6.2%-9.8%). This difference was significant (p<0.05).
These children also showed an increased number of carious teeth in the posterior
segments ranging from 16.7% for tooth 16 (p>O.05) to 41.2% for tooth 46 (p>O.05),
while in the deciduous dentition it ranged from 22.6% for tooth 61 (p>O.05) to 36.7% for
tooth75 ( p>O.05)and was not significant. The children with clefts also showed generally
delayed eruption in both the permanent and the deciduous dentitions. This was significant
for the lateral incisors in the deciduous dentition (pO.05).
Conclusions: Children with clefts had generally poor oral hygiene and gingival health
with an increased number of carious teeth compared to children without clefts. These
children should be considered to have an increased risk of developing dental diseases and
therefore,will require stringent oral hygiene instructions and regular reviews by dental
professionals. Their treatment should involve preventive and curative services in order to
maintain healthy primary and permanent dentitions.

Dissection contributes significantly to anatomical knowledge and the development of professionalism for medical students. This study assessed student emotional stress and coping in the anatomy lab and the perception of dissection on learning. A survey of Medicine I students (n=100) assessed: demographics, emotions and stress of the first dissection, anxiety, coping, and learning. With a response rate of 40%, our findings include: positive attitude towards the first dissection (n=33) although some students still found it stressful (n=17); cultural views impacted the lab experience (n=24); some used spirituality (n=10) or humor (n=6) to cope; most agreed that dissection enhanced understanding of anatomy (n=31) and the connection of between theoretical and applied knowledge (n=37); promoted teamwork (n=35); and highlighted respect for the human body (n=31) and the spirit of organ donation (n=28). While some have assumed that students have a negative attitude towards human dissection, our study showed that the majority of students reported a positive impact on various aspects of professionalism and humanism. We conclude that dissection is useful for students to establish not only technical skills and knowledge of the body, but also qualities associated with inter-professional teamwork and a humanistic attitude, without posing significant emotional stress.

OBJECTIVE: To determine the pattern of occurrence of dental injuries in the 0-15 year-olds. DESIGN: A retrospective study. SETTING: Kenyatta National Hospital, Nairobi. SUBJECTS: Five hundred and five patient records with dental injuries were retrieved and analysed. RESULTS: A total of 505 patient records with dental injuries were retrieved and analysed. Most of the injuries were recorded in the year 1999 (22.2%). Boys were more affected (63.0%) than girls (37.0%). The main presenting complaint recorded was pain (75.8%).The majority of the patients (69.5%) presented for treatment during the same day or the day after trauma. Falls were the leading cause of injuries (73.5%). Most injuries involved two teeth (47.1%) and the maxillary central incisors were the most affected teeth both in the primary (67.5%) and permanent (64.0%) dentitions. Luxation injuries were the most common type of dental trauma with 47.5% occurring in the permanent teeth and 77.3% in the primary teeth. The main radiographic investigation performed was intraoral periapical views (52.9%) following which dental extraction (34.4%) was the main treatment modality offered. CONCLUSION: Prospective cross-sectional studies to determine the prevalence of dental injuries are needed. Furthermore improving the knowledge of dental practitioners through continuing dental education programmes would help in updating them on current trends in managing these injuries.

OBJECTIVE: To determine the pattern of occurrence of dental injuries in the 0-15 year-olds. DESIGN: A retrospective study. SETTING: Kenyatta National Hospital, Nairobi. SUBJECTS: Five hundred and five patient records with dental injuries were retrieved and analysed. RESULTS: A total of 505 patient records with dental injuries were retrieved and analysed. Most of the injuries were recorded in the year 1999 (22.2%). Boys were more affected (63.0%) than girls (37.0%). The main presenting complaint recorded was pain (75.8%).The majority of the patients (69.5%) presented for treatment during the same day or the day after trauma. Falls were the leading cause of injuries (73.5%). Most injuries involved two teeth (47.1%) and the maxillary central incisors were the most affected teeth both in the primary (67.5%) and permanent (64.0%) dentitions. Luxation injuries were the most common type of dental trauma with 47.5% occurring in the permanent teeth and 77.3% in the primary teeth. The main radiographic investigation performed was intraoral periapical views (52.9%) following which dental extraction (34.4%) was the main treatment modality offered. CONCLUSION: Prospective cross-sectional studies to determine the prevalence of dental injuries are needed. Furthermore improving the knowledge of dental practitioners through continuing dental education programmes would help in updating them on current trends in managing these injuries.

OBJECTIVE: To determine the pattern of occurrence of dental injuries in the 0-15 year-olds. DESIGN: A retrospective study. SETTING: Kenyatta National Hospital, Nairobi. SUBJECTS: Five hundred and five patient records with dental injuries were retrieved and analysed. RESULTS: A total of 505 patient records with dental injuries were retrieved and analysed. Most of the injuries were recorded in the year 1999 (22.2%). Boys were more affected (63.0%) than girls (37.0%). The main presenting complaint recorded was pain (75.8%).The majority of the patients (69.5%) presented for treatment during the same day or the day after trauma. Falls were the leading cause of injuries (73.5%). Most injuries involved two teeth (47.1%) and the maxillary central incisors were the most affected teeth both in the primary (67.5%) and permanent (64.0%) dentitions. Luxation injuries were the most common type of dental trauma with 47.5% occurring in the permanent teeth and 77.3% in the primary teeth. The main radiographic investigation performed was intraoral periapical views (52.9%) following which dental extraction (34.4%) was the main treatment modality offered. CONCLUSION: Prospective cross-sectional studies to determine the prevalence of dental injuries are needed. Furthermore improving the knowledge of dental practitioners through continuing dental education programmes would help in updating them on current trends in managing these injuries.

Infection with Salmonella (S.) is the most frequently reported cause of bacterial food-borne illness worldwide. Poultry are a common source and, in recent years, much attention has been focused in determining the prevalence of Salmonella during the different stages in the poultry production chain. This article was designed to investigate the prevalence of Salmonella serovars in retail chicken meat sold in Hanoi. A total of 262 samples were randomly collected from retail markets and examined for the presence of Salmonella. Of these samples, 48.9% were found to be contaminated with Salmonella. Predominant serotypes were S. Agona, S. Emek, S. London. The prevalence of S. Enteritidis and S. Typhimurium was considered. These findings have highlighted the magnitude of Salmonella contamination in retail chicken meat in Hanoi. On the basis of these preliminary survey results, it is recommended that a cost-effective monitoring and surveillance system for Salmonella should be established in Hanoi. This system should be augmented by good agricultural and hygienic practices and well-designed longitudinal research activities on the whole poultry production chain.

The 24-hr LD50 of colchicine in newborn rats is 0.24 mg/kg, which is about 1/10 that observed in the adult. The 24-hr LD50 of colchicine was relatively constant in rats over 25 days of age. In an attempt to determine the mechanism of the increased sensitivity of the newborn rat to the toxic action of colchicine, the distribution of 3H after the administration of 3H-colchicine (0.1 mg/kg) was measured in 10- and 35-day-old rats. The concentration of 3H was higher in all tissues of the newborn than the adult after ip administration, suggesting an immaturity in the pathway for colchicine elimination. After iv administration, radioactivity disappeared much more slowly from the plasma of the newborn rat than from the adult. This was due to a lower capacity of the liver of the newborn to concentrate colchicine and to excrete it into the bile. Development of the hepatic excretory mechanism responsible for excretion of colchicine occurred at the same age as did the increase in LD50. These results suggest that colchicine is more toxic in the newborn because the drug remains in the body for a longer time due to immaturity of the liver excretory process.

Studies on rabbit production in Kenya have not included in-depth analysis of the potentials of keeping rabbits in the rural and urban household setting. In this study questionnaire and examination sheets were used to record the information. The results of this research revealed that rabbit farmers in Central, Nairobi and Rift Valley provinces practice small scale farming essentially due to small land space, which if well adopted, can be practiced widely. There was sustained interest in rabbit farming which was shown by a large proportion of farmers (51%) who had kept rabbits between 1 and 5 years. The most common breeds of rabbits kept were New Zealand white (73%), Californian (60%) and their cross breeds (51%) which were all suitable for meat production. This study revealed that farmers had limited access to technical information in rabbit farming and this was seen in the poor design and construction of the rabbit hutches. Majority of farmers (64%) bought their breeding stock from other farmers, with only a small proportion buying from breeding centres (17%). This practice of buying replacement stock among farmers was likely to lead to inbreeding. The major constraints of rabbit farming are those dealing with production; disease (83%), predators like rats (29%), death of rabbits (69%) and unavailability of rabbit feed (19%). The results also indicated that there are opportunities and challenges to increase rabbit production in the country though access to technology and marketing strategies are major hindrances to this development.

Background: Despite constant monitoring of anticoagulation in prosthetic valve patients, haematologic complications occur. This study documented the occurrence of such complications and associated risk factors at the Kenyatta National Hospital (KNH).
Study design: Observational study reviewing 142 patients, 39 prospective and 103 retrospective.
Outcome measures: International Normalised Ratio (INR); presence of signs and symptoms of haematological complications.
Results: Forty four (31%) patients presented with bleeding tendencies, 28 grade I and 4 grade III. The most common thromboembolic complication was headache in 33 (23.2%) patients. Mean duration of anticoagulation for patients with complications was 82.9 months (± 64), compared to 60.8 months (± 43.8) in those without. Nine patients were non-compliant in taking medications, haematologic complications presenting in 8 of them.
Conclusion: A positive association was established between hematologic complications and INR levels, duration of anticoagulation therapy, non-compliance in taking of medications, and increased period between clinic visits. Of these only the duration of anticoagulation was an independent predictor for haematological complications.

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Knowledge of factors that affect per-act infectivity of human immunodeficiency virus type 1 (HIV-1) is important for designing HIV-1 prevention interventions and for the mathematical modeling of the spread of HIV-1.

Knowledge of factors that affect per-act infectivity of human immunodeficiency virus type 1 (HIV-1) is important for designing HIV-1 prevention interventions and for the mathematical modeling of the spread of HIV-1.

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R.J. Cowen, J.H. Were and P.T. Vas: An Introduction to Calculus, Nairobi University Pren 1990.  

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J.H. Were, Faber Schander: Series for functions belonging to the Class Hw/Odessa State University 1988-23 pages Ukriniiti 05.05.88, No. 1072 yk88.

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The increasing availability of HIV clinics providing highly active antiretroviral therapy (HAART) has dramatically reduced AIDS-related morbidity and mortality in resource-limited settings. However, the impact of HAART on development and progression of cervical neoplasia and invasive cervical cancer remains uncertain [ The following popper user interface control may not be accessible. Tab to the next button to revert the control to an accessible version. Destroy user interface control1]. The longer life expectancy among HIV-infected women receiving HAART may actually increase the overall risk for cervical cancer, underscoring the need for prevention strategies for this high-risk population. A potentially cost-effective way of providing this “primary” care may be through HIV clinics, which are generally well staffed and have more resources than government or private clinics [ The following popper user interface control may not be accessible. Tab to the next button to revert the control to an accessible version. Destroy user interface control2]. In addition to utilizing the staffing and infrastructure in place to provide HIV care and HAART, incorporating cervical cancer screening into an HIV clinic visit may increase screening uptake and follow up. One key element of cervical cancer prevention is the coupling of accurate screening methodologies with safe and effective outpatient treatment for cervical neoplasia. The loop electrosurgical excision procedure (LEEP) has better efficacy among HIV-infected women than cryotherapy [ The following popper user interface control may not be accessible. Tab to the next button to revert the control to an accessible version. Destroy user interface control3], and although LEEP requires electricity, it has been used successfully in resource-limited settings [ The following popper user interface control may not be accessible. Tab to the next button to revert the control to an accessible version. Destroy user interface control4]. However, LEEP is generally considered a surgical procedure to be performed by physicians or highly-trained midwives. We sought to establish the feasibility and safety of training midlevel HIV primary care providers to perform LEEP in an HIV care and treatment clinic in Kisumu, Kenya. Ethical approval was obtained from all collaborating institutions prior to initiation of screening and treatment. This evaluation took place at the Family AIDS Care and Education Services (FACES) clinic in Kisumu, Kenya. Kisumu, Kenya’s third largest city, has a population of 400 000. FACES partners with the Kenyan Government to provide free HIV care services as per Ministry of Health guidelines. Most visits are done by clinical officers (physician assistants), with medical officers available for consultation. As part of the cervical cancer screening program, all interested clinical officers at FACES were offered LEEP training. Between October 2007 and October 2009, 4 clinical officers underwent training and certification, and performed 181 LEEPs. Women were followed up for complications by telephone at 1 week and during a return visit at 1 month. All women were seen within 6 weeks of LEEP. Five women (3%) had procedure-related complications (Table 1). With the exception of the antibiotics, no additional treatment or referral was required. In our experience, LEEP was performed safely by clinical officers within an HIV-care clinic, expanding potential options for cervical cancer screening programs.

Patterns of synaptic connections in the visual system are remarkably precise. These connections dictate the receptive field properties of individual visual neurons and ultimately determine the quality of visual perception. Spontaneous neural activity is necessary for the development of various receptive field properties and visual feature maps. In recent years, attention has shifted to understanding the mechanisms by which spontaneous activity in the developing retina, lateral geniculate nucleus, and visual cortex instruct the axonal and dendritic refinements that give rise to orderly connections in the visual system. Axon guidance cues and a growing list of other molecules, including immune system factors, have also recently been implicated in visual circuit wiring. A major goal now is to determine how these molecules cooperate with spontaneous and visually evoked activity to give rise to the circuits underlying precise receptive field tuning and orderly visual maps.

Patterns of synaptic connections in the visual system are remarkably precise. These connections dictate the receptive field properties of individual visual neurons and ultimately determine the quality of visual perception. Spontaneous neural activity is necessary for the development of various receptive field properties and visual feature maps. In recent years, attention has shifted to understanding the mechanisms by which spontaneous activity in the developing retina, lateral geniculate nucleus, and visual cortex instruct the axonal and dendritic refinements that give rise to orderly connections in the visual system. Axon guidance cues and a growing list of other molecules, including immune system factors, have also recently been implicated in visual circuit wiring. A major goal now is to determine how these molecules cooperate with spontaneous and visually evoked activity to give rise to the circuits underlying precise receptive field tuning and orderly visual maps.

Eye-specific visual connections are a prominent model system for exploring how precise circuits develop in the CNS and, in particular, for addressing the role of neural activity in synapse elimination and axon refinement. Recent experiments have identified the features of spontaneous retinal activity that mediate eye-specific retinogeniculate segregation, the synaptic events associated with this process, and the importance of axon guidance cues for organizing the overall layout of eye-specific maps. The classic model of ocular dominance column development, in which spontaneous retinal activity plays a crucial role, has also gained new support. Although many outstanding questions remain, the mechanisms that instruct eye-specific circuit development are becoming clear.

The profiles of prostanoid biosynthesis from endogenous arachidonic acid in 16 established cell lines derived from 4 histological classes of human carcinomas were determined by capillary gas chromatography-mass spectrometry. Detectable quantities of prostanoids were isolated from the culture medium of cell lines representative of the different histological classes of human tumors: colorectal adenocarcinomas (one of three cell lines); ovarian adenocarcinomas (one of three cell lines); prostate adenocarcinomas (zero of two cell lines); non-small cell carcinomas of the lung (four of five cell lines); and small cell carcinomas of the lung (zero of three cell lines). Prostaglandins E2 and F2 alpha were the only prostanoids synthesized in detectable quantities. Prostaglandin E2 biosynthesis (mean +/- SD), pmol/10(6) cells, n = 4) in cell lines exhibiting positive prostaglandin H synthase activity was: LoVo (colorectal adenocarcinoma, 0.4 +/- 0.1); A2780 (ovarian adenocarcinoma, 1.3 +/- 0.3); NCI-H322 (bronchioloalveolar cell carcinoma, 8.4 +/- 3.1); NCI-H358 (bronchioloalveolar cell carcinoma, 7.8 +/- 2.4); EKVX (adenocarcinoma of the lung, 21.3 +/- 5.5); and A427 (large cell undifferentiated carcinoma of the lung, 12.6 +/- 2.8). Prostaglandin F2 alpha production (pmol/10(6) cells +/- SD) was: LoVo (0.3 +/- 0.1); NCI-H322 (0.6 +/- 0.2); NCI-H358 (0.4 +/- 0.1); EKVX (1.8 +/- 0.4); and A427 (11.1 +/- 3.1). These findings suggest that within certain limitations cultured tumor cells provide simplified experimental systems for determination of prostaglandin biosynthetic characteristics of human tumors and that prostanoid biosynthesis may be particularly characteristic of certain non-small cell carcinomas of the lung.

Subdermal contraceptive implants have low discontinuation rates but are underused among young women in Africa. This study aimed to isolate the role initial contraceptive method has on preventing unintended pregnancy.

Simultaneous use of contraceptive hormones and anti-retroviral therapy (ART) may theoretically lessen the effectiveness of both. Women on ART need assurance that hormonal contraception is safe and effective. The sub-dermal implant is an ideal product to study: low and steady progestin release and no adherence uncertainties. We sought to determine if the medications' effectiveness is compromised.

Simultaneous use of contraceptive hormones and anti-retroviral therapy (ART) may theoretically lessen the effectiveness of both. Women on ART need assurance that hormonal contraception is safe and effective. The sub-dermal implant is an ideal product to study: low and steady progestin release and no adherence uncertainties. We sought to determine if the medications' effectiveness is compromised.

Subdermal contraceptive implants may be a reasonable option for young women in sub-Saharan Africa; little is known about factors associated with method uptake in this subpopulation.

Subdermal contraceptive implants have low discontinuation rates but are underused among young women in Africa. This study aimed to isolate the role initial contraceptive method has on preventing unintended pregnancy.

Subdermal contraceptive implants may be a reasonable option for young women in sub-Saharan Africa; little is known about factors associated with method uptake in this subpopulation.

In the last years, an increasing interest has been paid to the olfactory system, particularly to its abilities of plasticity and its potential continuous neurogenesis throughout adult life. Although mechanisms underlying adult neurogenesis have been largely investigated in animals, to some degree they remain unclear in humans. Based on human research findings, the present review will focus on the olfactory bulb as an evidence of the astonishing plasticity of the human olfactory system.

In the last years, an increasing interest has been paid to the olfactory system, particularly to its abilities of plasticity and its potential continuous neurogenesis throughout adult life. Although mechanisms underlying adult neurogenesis have been largely investigated in animals, to some degree they remain unclear in humans. Based on human research findings, the present review will focus on the olfactory bulb as an evidence of the astonishing plasticity of the human olfactory system.

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The dimension of the lower tarsus diminishes with aging. Changes in the number and size of the meibomian glands and in the character of intermingling fibroconnective tissues are thought to be responsible. Furthermore, such alterations of the structural integrity play an important role in the pathogenesis of entropion encountered commonly in the elderly. We have advocated the use of an autogenous cartilage graft harvested from the ear to correct the deformity, especially in instances where the conventional methods of correction have failed.

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Using the method of retrograde labeling of ganglion cells with HRP, we studied in adult rats the plastic changes in the retinogeniculate projections due to monocular enucleations shortly after birth. Four normal and 6 neonatally enucleated rats were used. In two of the normal and 4 of the enucleated rats a small amount of HRP was injected into the dorsal lateral geniculate nucleus (LGd) and in 4 other rats massive injections were made into the optic tract near the LGd. Neonatally unilaterally eye-enucleated rats were characterized by an expanded distribution of ipsilaterally projecting ganglion cells all over the retina of the remaining eye and by a densely packed distribution of these cells in the lower temporal retina in which area these cells have only a moderate density in normal rats. On the contrary, in the lower temporal retina of monocularly enucleated rats the incidence of contralaterally projecting ganglion cells was decreased. Soma areas of ipsi- and contralaterally projecting ganglion cells were measured for the peripheral crescent in lower temporal and lower nasal retinas. As compared with normal rats, neonatally enucleated rats had a larger mean soma area of ipsilaterally projecting cells and a smaller mean soma area of contralaterally projecting cells. This result was interpreted as suggesting that after neonatal monocular enucleation medium to large cells had changed their side of axonal projection from the contralateral to ipsilateral LGd.

Using the method of retrograde labeling of ganglion cells with HRP, we studied in adult rats the plastic changes in the retinogeniculate projections due to monocular enucleations shortly after birth. Four normal and 6 neonatally enucleated rats were used. In two of the normal and 4 of the enucleated rats a small amount of HRP was injected into the dorsal lateral geniculate nucleus (LGd) and in 4 other rats massive injections were made into the optic tract near the LGd. Neonatally unilaterally eye-enucleated rats were characterized by an expanded distribution of ipsilaterally projecting ganglion cells all over the retina of the remaining eye and by a densely packed distribution of these cells in the lower temporal retina in which area these cells have only a moderate density in normal rats. On the contrary, in the lower temporal retina of monocularly enucleated rats the incidence of contralaterally projecting ganglion cells was decreased. Soma areas of ipsi- and contralaterally projecting ganglion cells were measured for the peripheral crescent in lower temporal and lower nasal retinas. As compared with normal rats, neonatally enucleated rats had a larger mean soma area of ipsilaterally projecting cells and a smaller mean soma area of contralaterally projecting cells. This result was interpreted as suggesting that after neonatal monocular enucleation medium to large cells had changed their side of axonal projection from the contralateral to ipsilateral LGd.

Two methods of determination of trace elements in plant materials, viz. the fundamental parameters method (FPM) and the empirical method with the use of standard samples, were compared. Hay CRM and fresh tea leaves were used in measurements. Good agreement was achieved for the determination of a number of elements by both methods. Also Soil-7 Certified Reference Material (CRM) was analysed using emission-transmission method for absorption correction and FPM for concentration determination. The agreement with CRM was found to be reasonably good for several elements.

Pericytes play an important role in modulating angiogenesis, but the origin of these cells is poorly understood. To evaluate whether the mature vessel wall contains pericyte progenitor cells, nonendothelial mesenchymal cells isolated from the rat aorta were cultured in a serum-free medium optimized for stem cells. This method led to the isolation of anchorage-independent cells that proliferated slowly in suspension, forming spheroidal colonies. This process required basic fibroblast growth factor (bFGF) in the culture medium, because bFGF withdrawal caused the cells to attach to the culture dish and irreversibly lose their capacity to grow in suspension. Immunocytochemistry and RT-PCR analysis revealed the expression of the precursor cell markers CD34 and Tie-2 and the absence of endothelial cell markers (CD31 and endothelial nitric oxide synthase, eNOS) and smooth muscle cell markers (alpha-smooth muscle actin, alpha-SMA). In addition, spheroid-forming cells were positive for NG2, nestin, PDGF receptor (PDGFR)-alpha, and PDGFR-beta. Upon exposure to serum, these cells lost CD34 expression, acquired alpha-SMA, and attached to the culture dish. Returning these cells to serum-free medium failed to restore their original spheroid phenotype, suggesting terminal differentiation. When embedded in collagen gels, spheroid-forming cells rapidly migrated in response to PDGF-BB and became dendritic. Spheroid-forming cells cocultured in collagen with angiogenic outgrowths of rat aorta or isolated endothelial cells transformed into pericytes. These results demonstrate that the rat aorta contains primitive mesenchymal cells capable of pericyte differentiation. These immature cells may represent an important source of pericytes during angiogenesis in physiological and pathological processes. They may also provide a convenient supply of mural cells for vascular bioengineering applications.

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Kenya is one of Africa’s most dynamic and entrepreneurial economies, but one with increasing water security risks. These risks are of growing concern to the poor; where it is clear current poverty metrics do not capture the impact and implications of water shocks or long-term human exposure to water risks. This report highlights 4 significant but uncertain developments that will interact to determine Kenya’s progress in its quest to reach middle-income status by 2030 and improve water security for over 17 million poor people: the impacts of decentralisation resilience to climate shocks reducing inequality harnessing mobile ecosystems. The report presents potential locations to establish Water Security Observatories that address these key issues and developments. Through a risk-based approach and science-practitioner partnerships, the observatories are proposed to examine ‘small towns in fragile lands’ and ‘build water secure institutions’ with the goal of reducing water security risks for the poor. This paper is an output from the REACH Improving Water Security for the Poor programme

Kenya is one of Africa’s most dynamic and entrepreneurial economies, but one with increasing water security risks. These risks are of growing concern to the poor; where it is clear current poverty metrics do not capture the impact and implications of water shocks or long-term human exposure to water risks. This report highlights 4 significant but uncertain developments that will interact to determine Kenya’s progress in its quest to reach middle-income status by 2030 and improve water security for over 17 million poor people: the impacts of decentralisation resilience to climate shocks reducing inequality harnessing mobile ecosystems. The report presents potential locations to establish Water Security Observatories that address these key issues and developments. Through a risk-based approach and science-practitioner partnerships, the observatories are proposed to examine ‘small towns in fragile lands’ and ‘build water secure institutions’ with the goal of reducing water security risks for the poor. This paper is an output from the REACH Improving Water Security for the Poor programme

The purification and properties of a novel type of murein transglycosylase from Escherichia coli are described. The purified enzyme appears as a single band on sodium dodecyl sulfate-polyacrylamide gels and has an apparent molecular weight of approximately 65,000 as estimated by gel filtration and gel electrophoresis. It degrades pure murein sacculi from E. coli almost completely into low-molecular-weight products. The two prominent muropeptide fragments in the digest are the disaccharide-tripeptide N-acetylglucosamine-N-acetylmuramic acid-L-alanine-D-iso-glutamic acid-meso-diaminopimelic acid and the corresponding disaccharide-tetrapeptide N-acetylglucosamine-N-acetylmuramic acid-L-alanine-D-iso-glutamic acid-meso-diaminopimelic acid-D-alanine. The unique feature of these compounds is that the disaccharide has no reducing end group and that the muramic acid residue possesses an internal 1 leads to 6 anhydro linkage. The new lytic enzyme is designated as a murein: murein transglycosylase. Its possible role in the rearrangement of murein during cell growth and division is discussed.

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BACKGROUND: Spermatogenesis and epididymal function depend on testicular steroids with estrogens being important regulatory factors. However, testicular estrogen secretion shows distinct species specificities, with the boar being characterized by the production of high amounts of estrone [E1] and estronesulphate [E1S]. As the boar testis also expresses estrogen sulphatase [StS] and sulphotransferase [EST] the present paper is based on the hypothesis that local availability of biologically active estrogens results from an interplay between estrogen synthesis and local activities of StS and EST. METHODS: Blood was collected during castration of 37 boars, aged between 98 (peripubertal) to 2 793 (old sexually mature) days, from the testicular vein and artery and peripheral circulation; E1, E1S, testosterone [T] and progesterone [P] were determined by established RIA-procedures. Similarly seminal plasma from 21 sexually mature boars was assessed. StS- and EST-activity were determined in testicular- and epididymal homogenates of 3 sexually mature boars (200 d) using (3)H-E1S resp. (3)H-E1 as substrate. Immunohistochemistry [IHC] was applied to locate EST- expressing cells in testes in relation to age and in the epididymis of 3 mature boars. RESULTS: Hormone data showed a high variability. A significant age dependent increase was only observed for E1 and E1S in the peripheral circulation with absolute values being highest for E1S (5-60 nmol/l), followed by T (2.6-14 nmol/l), P (0.5-1.48 nmol/l) and E1 (0.24-0.84 nmol/l). Testicular vein concentrations always exceeded those in the testicular artery with the differences being significant for E1 and P, group 1. Concentrations in the testicular artery and peripheral vein plasma were not different but higher (p<0.0001) than those in seminal plasma with the exception of E1. StS activity was higher (p<0.001) in the testis than the epididymis. EST activity was high in epididymal homogenates and at the level of detection in testis homogenates. IHC located EST in virtually all epididymal epithelial cells. In the testis the number of positive staining Leydig cells decreased (p<0.05) from 72% in the premature to 57% in the mature boars. CONCLUSION: The provision of biologically active estrogens to the testicular and epididymal compartment is controlled by a complex regulatory system, with the sulphatase pathway being an important component. P is a secretory product of the testis, E1 and E1S are not actively enriched in seminal plasma.

The brain has a remarkable capacity to adapt to alterations in its sensory environment, which is normally much more pronounced in juvenile animals. Here we show that in adult mice, the ability to adapt to changes can be improved profoundly if the mouse has already experienced a similar change in its sensory environment earlier in life. Using the standard model for sensory plasticity in mouse visual cortex-ocular dominance (OD) plasticity-we found that a transient shift in OD, induced by monocular deprivation (MD) earlier in life, renders the adult visual cortex highly susceptible to subsequent MD many weeks later. Irrespective of whether the first MD was experienced during the critical period (around postnatal day 28) or in adulthood, OD shifts induced by a second MD were faster, more persistent and specific to repeated deprivation of the same eye. The capacity for plasticity in the mammalian cortex can therefore be conditioned by past experience.

The brain has a remarkable capacity to adapt to alterations in its sensory environment, which is normally much more pronounced in juvenile animals. Here we show that in adult mice, the ability to adapt to changes can be improved profoundly if the mouse has already experienced a similar change in its sensory environment earlier in life. Using the standard model for sensory plasticity in mouse visual cortex-ocular dominance (OD) plasticity-we found that a transient shift in OD, induced by monocular deprivation (MD) earlier in life, renders the adult visual cortex highly susceptible to subsequent MD many weeks later. Irrespective of whether the first MD was experienced during the critical period (around postnatal day 28) or in adulthood, OD shifts induced by a second MD were faster, more persistent and specific to repeated deprivation of the same eye. The capacity for plasticity in the mammalian cortex can therefore be conditioned by past experience.

The boron-doped diamond electrode has been widely applied in electrochemical process for wastewater treatment based on the generation of hydroxyl radicals (•OH). This study investigated the formation efficiency of 2-HTA through the interaction between •OH radical and terephthalic acid (TA) to monitor the •OH formation. Results show that the 2-HTA formation efficiency did not depend on the initial concentration of scavenger (here, TA) in the investigated range of 0.1 to 1 mM TA. Meanwhile, other factors, such as current density, supporting electrolyte, sodium hydroxide have a significant influence. The optimal condition was established: concentration of electrolyte (0.05 M Na2SO4); initial concentration of TA (0.1 mM); concentration of NaOH (1 mM); current density (j = 20 mA cm–2). The selectivity of TA was evaluated by Faradaic efficiency (η) and hydroxylation yield (γTAOH), indicating that Faradaic efficiency (η) for 2-HTA formation was in the range of 10–5–10–7, while the hydroxylation yield of •OH (γTAOH) into 2-HTA was 0.03–0.12.

Synaptic plasticity is the experience-dependent change in connectivity between neurons that is believed to underlie learning and memory. Here, we discuss the cellular and molecular processes that are altered when a neuron responds to external stimuli, and how these alterations lead to an increase or decrease in synaptic connectivity. Modification of synaptic components and changes in gene expression are necessary for many forms of plasticity. We focus on excitatory neurons in the mammalian hippocampus, one of the best-studied model systems of learning-related plasticity.

The concept of vascular pruning, the "cuting-off" of vessels, is gaining importance due to expansion of angio-modulating therapies. The proangiogenic effects of vascular endothelial growth factor (VEGF) are broadly described, but the mechanisms of structural alterations by its downregulation are not known.

Inhibitors of angiogenesis and radiation induce compensatory changes in the tumor vasculature both during and after cessation of treatment. In numerous preclinical studies, angiogenesis inhibitors were shown to be efficient in the treatment of many pathological conditions, including solid cancers. In most clinical trials, however, this approach turned out to have no significant effect, especially if applied as monotherapy. Recovery of tumors after therapy is a major problem in the management of cancer patients. The mechanisms underlying tumor recovery (or therapy resistance) have not yet been explicitly elucidated. This review deals with the transient switch from sprouting to intussusceptive angiogenesis, which may be an adaptive response of tumor vasculature to cancer therapy that allows the vasculature to maintain its functional properties. Potential candidates for molecular targeting of this angioadaptive mechanism are yet to be elucidated in order to improve the currently poor efficacy of contemporary antiangiogenic therapies.

Angiogenesis is a highly coordinated, extremely complex process orchestrated by multiple signaling molecules and blood flow conditions. While sprouting mode of angiogenesis is very well investigated, the molecular mechanisms underlying intussusception, the second mode of angiogenesis, remain largely unclear. In the current study two molecules involved in vascular growth and differentiation, namely endoglin (ENG/CD105) and chicken ovalbumin upstream promoter transcription factor II (COUP-TFII) were examined to unravel their specific roles in angiogenesis. Down- respectively up-regulation of both molecules tightly correlates with intussusceptive microvascular growth. Upon ENG inhibition in chicken embryo model, formation of irregular capillary meshwork accompanied by increased expression of COUP-TFII could be observed. This dynamic expression pattern of ENG and COUP-TFII during vascular development and remodeling correlated with formation of pillars and progression of intussusceptive angiogenesis. Similar findings could be observed in mammalian model of acute rat Thy1.1 glomerulonephritis, which was induced by intravenous injection of anti-Thy1 antibody and has shown upregulation of COUP-TFII in initial phase of intussusception, while ENG expression was not disturbed compared to the controls but decreased over the time of pillar formation. In this study, we have shown that ENG inhibition and at the same time up-regulation of COUP-TFII expression promotes intussusceptive angiogenesis.

The effect of herpes simplex virus type 2 (HSV-2) suppression on human immunodeficiency virus type 1 (HIV-1) RNA in the context of prevention of mother-to-child transmission (PMTCT) interventions is unknown. Methods. Between April 2008 and August 2010, we conducted a randomized, double-blind trial of twice daily 500 mg valacyclovir or placebo beginning at 34 weeks gestation in 148 HIV-1/HSV-2 coinfected pregnant Kenyan women ineligible for highly active antiretroviral therapy (CD4 > 250 cells/mm3). Women received zidovudine and single dose nevirapine for PMTCT and were followed until 12 months postpartum. Results. Mean baseline plasma HIV-1 RNA was 3.88 log10 copies/mL. Mean plasma HIV-1 was lower during pregnancy (−.56 log10 copies/mL; 95% confidence interval [CI], −.77 to −.34) and after 6 weeks postpartum (−.51 log10 copies/mL; 95% CI, −.73 to −.30) in the valacyclovir arm than the placebo arm. Valacyclovir reduced breast milk HIV-1 RNA detection at 6 and 14 weeks postpartum compared with placebo (30% lower, P = .04; 46% lower, P = .01, respectively), but not after 14 weeks. Cervical HIV-1 RNA detection was similar between arms (P = .91). Conclusions. Valacyclovir significantly decreased early breast milk and plasma HIV-1 RNA among women receiving PMTCT.

Study region

the Turkwel river basin, Kenya experiences a high level of water scarcity due to its arid climate, high rainfall variability and rapidly growing water demand.
Study focus

Climate change, variability and rapid growth in water demand pose significant challenges to current and future water resources planning and allocation worldwide. In this paper a novel decision-scaling approach was applied to model the response of the Turkwel river basin’s water resources system to growing demand and climate stressors. A climate response surface was constructed by combining a water resource system model, climate data, and a range of water demand scenarios.
New hydrological insights

The results show that climate variability and increased water demand are each important drivers of water scarcity in the basin. Increases in water demand due to expanded irrigation strongly influences on the resilience of the basin’s water resource system to droughts caused by the global climate variability. The climate response surface offers a visual and flexible tool for decision-makers to understand the ways in which the system responds to climate variability and development scenarios. Policy decisions to accelerate water-dependent development and poverty reduction in arid and semi-arid lands that are characterised by rapid demographic, political and economic change in the short- to medium term have to promote low-regrets approaches that incorporate longer-term climate uncertainty.

The first objective in diabetic ketoacidosis is to restore the circulating volume and improve tissue perfusion. In any form of hypovolaemic shock the most efficient way of restoring circulating volume is to be use colloid solutions rather than crystalloids. At least three times the amount of crystalloid must be used to achieve the same effect. The historical reason for using isotonic saline in diabetic ketoacidosis is related not to its similarity to the fluid lost, but to its supposed efficiency in correcting the circulating volume. Excess crystalloid expands the interstitial space which results in pulmonary oedema, peripheral oedema and possibly cerebral oedema. Although currently difficult to define precisely in their more subtle forms, they all produce adverse pathophysiological effects. The fluid loss in diabetic ketoacidosis is equivalent to "half-normal" saline, a relatively hypotonic solution. As well as causing extensive oedema, resuscitation with isotonic saline can increase serum sodium and osmolarity while not providing free water to replace the intracellular losses.

Objective Vasa vasorum (VV) have been implicated to play a role in the pathogenesis of atherosclerosis. This study was designed to describe the distribution of VV density in different vascular beds in humans and to investigate the association between VV density and the known distribution of atherosclerosis in human arteries. Methods Forty-two human arteries, harvested at autopsy or after explantation, were analyzed by three-dimensional microscopic-computed tomography (micro-CT). VV density, endothelial-surface-fraction (Σ VV endothelial-surface-area/vessel-wall-volume) and vascular-area-fraction (Σ VV area/vessel-wall-area) were calculated for coronary, renal and femoral arteries. Representatively five coronary, renal and femoral arteries were stained for endothelial cells (von Willebrand-Factor), macrophages (CD68), vascular endothelial growth factor (VEGF) and collagen (Sirius Red). Results Coronary arteries showed a higher VV density compared to renal and femoral arteries (2.12±0.26n/mm2 versus 0.61±0.06n/mm2 and 0.66±0.11n/mm2; P{\textless}0.05 for both) as well as a higher endothelial-surface-fraction and vascular-area-fraction. Histology showed a positive correlation between histologically derived VV density and CD68-positive cells/area (r=0.54, P{\textless}0.01), VEGF-immunoreactivity/area (r=0.55, P{\textless}0.01) and a negative correlation between VV density and collagen I content (r=0.66, P{\textless}0.05). Conclusion This micro-CT study highlights a higher VV density in coronary than in peripheral arteries, supporting the relation between VV density and the susceptibility to atherosclerosis in different vascular beds in humans.