Plasmodium falciparum malaria causes 1-2 million deaths per year. Most deaths occur as a result of complications such as severe anemia and cerebral malaria (CM) (coma). Red cells of children with severe malaria-associated anemia (SMA) have acquired deficiencies in the complement regulatory proteins complement receptor 1 (CR1, CD35) and decay accelerating factor (DAF, CD55). We investigated whether these deficiencies affect the ability of erythrocytes to bind immune complexes (ICs) and regulate complement activation. We recruited 75 children with SMA (Hb < or = 6 g/dL) from the holoendemic malaria region of the Lake Victoria basin, western Kenya, and 74 age- and gender-matched uncomplicated malaria controls. In addition, we recruited 32 children with CM and 52 age- and gender-matched controls. Deficiencies in red cell CR1 and CD55 in children with SMA were accompanied by a marked decline in IC binding capacity and increased C3b deposition in vivo and ex vivo. Importantly, these changes were specific because they were not seen in red cells of children with CM or their controls. These data suggest that the declines in red cell CR1 and CD55 seen in children with SMA are of physiologic significance and may predispose erythrocytes to complement-mediated damage and phagocytosis in vivo.

Understanding how individuals with a high degree of HIV exposure avoid persistent infection is paramount to HIV vaccine design. Evidence suggests that mucosal immunity, particularly virus-specific CTL, could be critically important in protection against sexually acquired HIV infection. Therefore, we have looked for the presence of HIV-specific CD8+ T cells in cervical mononuclear cells from a subgroup of highly HIV-exposed but persistently seronegative female sex workers in Nairobi. An enzyme-linked immunospot assay was used to measure IFN-gamma release in response to known class I HLA-restricted CTL epitope peptides using effector cells from the blood and cervix of HIV-1-resistant and -infected sex workers and from lower-risk uninfected controls. Eleven of 16 resistant sex workers had HIV-specific CD8+ T cells in the cervix, and a similar number had detectable responses in blood. Where both blood and cervical responses were detected in the same individual, the specificity of the responses was similar. Neither cervical nor blood responses were detected in lower-risk control donors. HIV-specific CD8+ T cell frequencies in the cervix of HIV-resistant sex workers were slightly higher than in blood, while in HIV-infected donor cervical response frequencies were markedly lower than blood, so that there was relative enrichment of cervical responses in HIV-resistant compared with HIV-infected donors. HIV-specific CD8+ T cell responses in the absence of detectable HIV infection in the genital mucosa of HIV-1-resistant sex workers may be playing an important part in protective immunity against heterosexual HIV-1 transmission.

SUMMARY LIII)' lIIorpllOlogiClI changcs ill the goat ,csris after:. sillgle illlraperilOlieal injec,ioll of ethalle ,lillie' I.:lIIeslll"llOnarc (EI )S) werc investigatcd mint; (1Orh liglH alld deCll'On microscopy. The (olllpolind was ;almillistered at two dose Icvels: 75 mgll

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Recent efforts to develop ox-drawn equipment in Kenya arise out of the dilemma caused by unsuccessful efforts to promote tractors. The country has a number of about 10 000 tractors cultivating about 600 000 ha in the large-farm sector and 42 000 ha in the small-farm sector. The tractor market has slowed down to less than 1000 a year. The failure of tractor mechanization in small-scale farming coupled with the lack of ox-drawn equipment means that about 84% of smallholdings is using hand tools. In 1975, a workshop concluded that expanded ox-cultivation has a major part to play in increased agricultural production. After 4 years, the first 3 stages of development of ox-drawn equipment were accomplished. Aspects of local manufacture, training, extension and marketing are discussed.

Recent efforts to develop ox-drawn equipment in Kenya arise out of the dilemma caused by unsuccessful efforts to promote tractors. The country has a number of about 10 000 tractors cultivating about 600 000 ha in the large-farm sector and 42 000 ha in the small-farm sector. The tractor market has slowed down to less than 1000 a year. The failure of tractor mechanization in small-scale farming coupled with the lack of ox-drawn equipment means that about 84% of smallholdings is using hand tools. In 1975, a workshop concluded that expanded ox-cultivation has a major part to play in increased agricultural production. After 4 years, the first 3 stages of development of ox-drawn equipment were accomplished. Aspects of local manufacture, training, extension and marketing are discussed.

A study of malaria on the Kano Plain, Kisumu District, Western Kenya, was carried out between April and August, 1985. The study included a knowledge, attitudes and practices (K.A.P.) survey on malaria illness and the mosquito vector. Overall knowledge about malaria illness was found to be good. However, treatment and prevention practices of malaria were found to be poor. Knowledge of the mosquito and its relationship to malaria was found to be high. Knowledge of methods of prevention of mosquito bites was also found to be high but actual use of the methods was low. Knowledge of traditional methods of prevention of mosquito bites was also found to be high. Actual use was again found to be low.

Department of Periodontology/ Community and Preventive Dentistry, School of Dental Sciences, University of Nairobi, P.O. Box 19676 - 00202, Nairobi, Kenya. OBJECTIVE: To determine the influence of oral hygiene habits and practices on the risk of developing oral leukoplakia. DESIGN: Case control study. SETTING: Githongo sublocation in Meru District. SUBJECTS: Eighty five cases and 141 controls identified in a house-to-house screening. RESULTS: The relative risk (RR) of oral leukoplakia increased gradually across the various brushing frequencies from the reference RR of 1.0 in those who brushed three times a day, to 7.6 in the "don't brush" group. The trend of increase was statistically significant (X2 for Trend : p = 0.001). The use of chewing stick as compared to conventional tooth brush had no significant influence on RR of oral leukoplakia. Non-users of toothpastes had a significantly higher risk of oral leukoplakia than users (RR = 1.8; 95% confidence levels (CI) = 1.4-2.5). Among tobacco smokers, the RR increased from 4.6 in those who brushed to 7.3 in those who did not brush. Among non-smokers, the RR of oral leukoplakia in those who did not brush (1.8) compared to those who brushed was also statistically significant (95% CL = 1.6-3.8). CONCLUSION: Failure to brush teeth and none use of toothpastes are significantly associated with the development of oral leukoplakia, while the choice of brushing tools between conventional toothbrush and chewing stick is not. In addition, failure to brush teeth appeared to potentiate the effect of smoking tobacco in the development of oral leukoplakia. Recommendations: Oral health education, instruction and motivation for the improvement of oral hygiene habits and practices; and therefore oral hygiene status, should be among the strategies used in oral leukoplakia preventive and control programmes.

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OBJECTIVE: To analyse the underlying aetiology, precipitating factors and certain socio-demographic determinants in patients admitted to Kenyatta National Hospital, Nairobi in congestive heart failure. DESIGN: Cross sectional descriptive study. SUBJECT: All patients aged thirteen years and above of either sex consecutively admitted with clinical diagnosis of congestive heart failure. SETTING: Kenyatta National Hospital (KNH), a national referral hospital. PATIENT EVALUATION: Detailed history including socio-demographic characteristics and physical examination was done. Patients underwent haematological and biochemistry tests followed by a chest x-ray, ECG and 2D Echo-doppler examination. Blood culture sensitivity was done when clinically indicated. RESULTS: Ninety one patients were studied, 44 males and 47 females. Almost 32% had rheumatic heart disease, 25.2% had cardiomyopathy, 17.6% hypertensive heart disease, 13.2% had pericardial disease while 2.2% had ischaemic heart disease. Three quarters of patients with hypertensive heart disease were above the age of 50 years, while 79% of patients with rheumatic heart disease were below the age of 30 years. Factors associated with patient deterioration leading to admission with congestive heart failure (CHF) included inadequate therapy (27.4%), arrhythmia (20.9%), respiratory infections (17.6%), anaemia (13.2%) and infective endocardiatis. Sixty two per cent of patients investigated were in New York Heart Association (NYHA) functional classification class IV, 31.9% in class III and 5.5% in class II. CONCLUSION: Congestive heart failure constitutes 3.3% of all medical admissions at KNH. Rheumatic heart disease is the commonest cause of congestive heart failure in our set-up while inadequate therapy, arrhythmias and respiratory infections are the three major causes of decompensation in our patients with cardiac disease.

OBJECTIVE: To analyse the underlying aetiology, precipitating factors and certain socio-demographic determinants in patients admitted to Kenyatta National Hospital, Nairobi in congestive heart failure. DESIGN: Cross sectional descriptive study. SUBJECT: All patients aged thirteen years and above of either sex consecutively admitted with clinical diagnosis of congestive heart failure. SETTING: Kenyatta National Hospital (KNH), a national referral hospital. PATIENT EVALUATION: Detailed history including socio-demographic characteristics and physical examination was done. Patients underwent haematological and biochemistry tests followed by a chest x-ray, ECG and 2D Echo-doppler examination. Blood culture sensitivity was done when clinically indicated. RESULTS: Ninety one patients were studied, 44 males and 47 females. Almost 32% had rheumatic heart disease, 25.2% had cardiomyopathy, 17.6% hypertensive heart disease, 13.2% had pericardial disease while 2.2% had ischaemic heart disease. Three quarters of patients with hypertensive heart disease were above the age of 50 years, while 79% of patients with rheumatic heart disease were below the age of 30 years. Factors associated with patient deterioration leading to admission with congestive heart failure (CHF) included inadequate therapy (27.4%), arrhythmia (20.9%), respiratory infections (17.6%), anaemia (13.2%) and infective endocardiatis. Sixty two per cent of patients investigated were in New York Heart Association (NYHA) functional classification class IV, 31.9% in class III and 5.5% in class II. CONCLUSION: Congestive heart failure constitutes 3.3% of all medical admissions at KNH. Rheumatic heart disease is the commonest cause of congestive heart failure in our set-up while inadequate therapy, arrhythmias and respiratory infections are the three major causes of decompensation in our patients with cardiac disease.

socio-demographic determinants in patients admitted to Kenyatta National Hospital, Nairobi in congestive heart failure. DESIGN: Cross sectional descriptive study. SUBJECT: All patients aged thirteen years and above of either sex consecutively admitted with clinical diagnosis of congestive heart failure. SETTING: Kenyatta National Hospital (KNH), a national referral hospital. PATIENT EVALUATION: Detailed history including socio-demographic characteristics and physical examination was done. Patients underwent haematological and biochemistry tests followed by a chest x-ray, ECG and 2D Echo-doppler examination. Blood culture sensitivity was done when clinically indicated. RESULTS: Ninety one patients were studied, 44 males and 47 females. Almost 32% had rheumatic heart disease, 25.2% had cardiomyopathy, 17.6% hypertensive heart disease, 13.2% had pericardial disease while 2.2% had ischaemic heart disease. Three quarters of patients with hypertensive heart disease were above the age of 50 years, while 79% of patients with rheumatic heart disease were below the age of 30 years. Factors associated with patient deterioration leading to admission with congestive heart failure (CHF) included inadequate therapy (27.4%), arrhythmia (20.9%), respiratory infections (17.6%), anaemia (13.2%) and infective endocardiatis. Sixty two per cent of patients investigated were in New York Heart Association (NYHA) functional classification class IV, 31.9% in class III and 5.5% in class II. CONCLUSION: Congestive heart failure constitutes 3.3% of all medical admissions at KNH. Rheumatic heart disease is the commonest cause of congestive heart failure in our set-up while inadequate therapy, arrhythmias and respiratory infections are the three major causes of decompensation in our patients with cardiac disease.

socio-demographic determinants in patients admitted to Kenyatta National Hospital, Nairobi in congestive heart failure. DESIGN: Cross sectional descriptive study. SUBJECT: All patients aged thirteen years and above of either sex consecutively admitted with clinical diagnosis of congestive heart failure. SETTING: Kenyatta National Hospital (KNH), a national referral hospital. PATIENT EVALUATION: Detailed history including socio-demographic characteristics and physical examination was done. Patients underwent haematological and biochemistry tests followed by a chest x-ray, ECG and 2D Echo-doppler examination. Blood culture sensitivity was done when clinically indicated. RESULTS: Ninety one patients were studied, 44 males and 47 females. Almost 32% had rheumatic heart disease, 25.2% had cardiomyopathy, 17.6% hypertensive heart disease, 13.2% had pericardial disease while 2.2% had ischaemic heart disease. Three quarters of patients with hypertensive heart disease were above the age of 50 years, while 79% of patients with rheumatic heart disease were below the age of 30 years. Factors associated with patient deterioration leading to admission with congestive heart failure (CHF) included inadequate therapy (27.4%), arrhythmia (20.9%), respiratory infections (17.6%), anaemia (13.2%) and infective endocardiatis. Sixty two per cent of patients investigated were in New York Heart Association (NYHA) functional classification class IV, 31.9% in class III and 5.5% in class II. CONCLUSION: Congestive heart failure constitutes 3.3% of all medical admissions at KNH. Rheumatic heart disease is the commonest cause of congestive heart failure in our set-up while inadequate therapy, arrhythmias and respiratory infections are the three major causes of decompensation in our patients with cardiac disease.

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Ninety seven patients were examined for dental caries using two standard methods: (a) clinical examination based on WHO Basic Methods Oral Health surveys and (b) radiographic examination. Clinical examination method under records caries by upto 40%. Such under recording may give an impression of a decreasing caries prevalence in epidemiological studies.

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Ninety seven patients were examined for dental caries using two standard methods: (a) clinical examination based on WHO Basic Methods Oral Health surveys and (b) radiographic examination. Clinical examination method under records caries by upto 40%. Such under recording may give an impression of a decreasing caries prevalence in epidemiological studies.

Department of Medical Physiology, Moi University, P.O Box 4606, Eldoret, Kenya. erenoyungu2002@yahoo.co.uk ETHNOPHARMACOLOGICAL RELEVANCE: Catha edulis (khat) is a plant whose fresh young leaves are used by an estimated five million people in eastern Africa and the Arabian Peninsula as a drug of recreation. The fresh leaves and shoots are rich in cathinone, a psychostimulant with effects similar to those of amphetamines. Psychostimulants produce a dose-related excitation of the central nervous system which can lead to seizures and convulsions. However there are no reports on studies of the effect of this herb on brain excitability and seizures. This knowledge is useful for doctors who may prescribe drugs whose side effects include lowering seizure threshold because there could be additive proconvulsant effect among khat users. AIM OF THE STUDY: to determined whether khat lowers pentylenetetrazole (PTZ) seizure threshold. METHODOLOGY: Male Sprague dawley rats were given fresh aqueous khat extract, old aqueous khat extract (3 g/kg bw), methylphenidate or saline and the timed intravenous (PTZ) seizure threshold test was used to study its effect on seizure threshold. RESULTS: Fresh khat (3 g/kg) and methylphenidate (4 mg/kg) lowered PTZ seizure threshold. CONCLUSION: Khat lowers seizure threshold. PMID: 19056477 [PubMed - indexed for MEDLINE]

Department of Medical Physiology, Moi University, P.O. Box 4606, Eldoret, Kenya. BACKGROUND: Khat is a plant whose young shoots and leaves are habitually used in Eastern Africa and the Arabian Peninsula as a drug of recreation. Although it is used without any control in these regions, it contains two controlled substances, cathinone (schedule I) which is present in fresh khat and cathine (schedule VI) which is a degradation product of cathinone abundant in old khat. OBJECTIVE: To determine the effect of khat on locomotor behaviour and seizures in rats. DESIGN: Experimental study. SETTING: University of Nairobi. SUBJECTS: Adult male rats in groups of six were given fresh khat, old khat, methylphenidate and saline at varying doses and observed over three hours. RESULTS: Fresh khat at low doses and old khat at high doses stimulated locomotor activity. High doses of fresh and old khat induced stereotype behaviour and seizures. CONCLUSION: The results show that khat stimulates locomotor and stereotypic behavioural activity and can induce seizures; results similar to those observed with amphetamine analogs. PMID: 17892196 [PubMed - indexed for MEDLINE]

In contrast with mammalian cells, little is known about the control of Ca2+ entry into primitive protozoans. Here we report that Ca2+ influx in pathogenic Trypanosoma brucei can be regulated by phospholipase A2 (PLA2) and the subsequent release of arachidonic acid (AA). Several PLA2 inhibitors blocked Ca2+ entry; 3-(4-octadecyl)-benzoylacrylic acid (OBAA; IC50 0.4+/-0.1 microM) was the most potent. We identified in live trypanosomes PLA2 activity that was sensitive to OBAA and could be stimulated by Ca2+, suggesting the presence of positive feedback control. The cell-associated PLA2 activity was able to release [14C]AA from labelled phospholipid substrates. Exogenous AA (5-50 microM) also initiated Ca2+ entry in a manner that was inhibited by the Ca2+ antagonist La3+ (100 microM). Ca2+ entry did not depend on AA metabolism or protein kinase activation. The cell response was specific for AA, and fatty acids with greater saturation than tetraeicosanoic acid (AA) or with chain lengths less than C20 exhibited greatly diminished ability to initiate Ca2+ influx. Myristate and palmitate inhibited PLA2 activity and also inhibited Ca2+ influx. Overall, these results demonstrate that Ca2+ entry into T. brucei can result from phospholipid hydrolysis and the release of eicosanoic acids.