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Biomedical subjects

D L Mwaniki

Publications and source records attributed to D L Mwaniki.

At least 19 recordsLinked to original sources
PubMed2005

HIV type 1 subtypes in circulation in northern Kenya.

The genetic subtypes of HIV-1 circulating in northern Kenya have not been characterized. Here we report the partial sequencing and analysis of samples collected in the years 2003 and 2004 from 72 HIV-1-positive patients in northern Kenya, which borders Ethiopia, Somalia, and Sudan. From the analysis of partial env sequences, it was determined that 50% were subtype A, 39% subtype C, and 11% subtype D. This shows that in the northern border region of Kenya subtypes A and C are the dominant HIV-1 subtypes in circulation. Ethiopia is dominated mainly by HIV-1 subtype C, which incidentally is the dominant subtype in the town of Moyale, which borders Ethiopia. These results show that cross-border movements play an important role in the circulation of subtypes in Northern Kenya.

Adolescent↗
PubMed2001

Symptoms in health personnel exposed to disinfectants.

BACKGROUND: While the biocidal efficacy of disinfectants available for use in health facilities has been widely investigated, little attention has been paid to their potential side effects to users. OBJECTIVE: To describe the occurrence of symptoms attributable to occupational exposure to disinfectants with emphasis on gluteraldehyde. DESIGN: Exploratory cross-sectional study. SETTING: Kenyan health facilities. SUBJECTS: One hundred and fifteen members of various health cadres. RESULTS: All the respondents reported using disinfectants. Glutaraldehyde-based preparations, either alone or alongside other agents (excluding hypochlorite), were used by 52.2% of the respondents. Hypochlorite-based preparations, either alone or alongside other agents, were used by 18.3%, while cetrimide preparations and ethanol alongside other agents were used by 13% of the respondents. More than sixty two per cent of the respondents had suffered one or more symptoms during the use of these disinfectants. Among the users of glutaraldehyde preparations, the most common symptoms reported were sneezing (38.3%), headache (31.7%), watering of eyes (25%), skin rash (10%) and chronic cough (8.3%). Among users of hypochlorite and cetrimide preparations, the most commonly reported symptoms were sneezing, headaches and watering of eyes. CONCLUSIONS: Our findings suggest possible occupation-related adverse reactions that may be attributed to the use of disinfectants. Awareness of these potential hazards needs to be increased among users and efforts made to introduce techniques to minimise exposure to liquid and vapourised disinfectants. Further studies involving larger sample sizes, are necessary to unequivocally apportion the various symptoms to specific disinfecting agents.

Cross-Sectional Studies↗
PubMed2001

Influence of cigarette filters on the risk of developing oral leukoplakia in a Kenyan population.

OBJECTIVE: To determine the influence of cigarette filters and the effect of smoking Kiraiku (home processed, hand rolled tobacco) on the risk of developing oral leukoplakia among cigarette smokers. DESIGN: Case control using population-based study groups in a Kenyan rural community. MATERIALS AND METHODS: 85 cases and 141 controls identified in a cross-section house-to-house screening of subjects aged 15 years and over and matched for sex, age (+/- 3 years) and cluster origin were compared for their use of filter and non-filter cigarettes as well as their history of smoking Kiraiku. RESULTS: The relative risk (RR) of oral leukoplakia was 9.1 (95% confidence intervals (CI) = 4.1-20.2) in smokers of filter cigarettes and 9.8 (95% CI = 2.3-47.0) in smokers of non-filter cigarettes. The RR in the latter compared to the former was 1.1 and was not statistically significant. Regarding the influence of smoking Kiraiku, the RR of this lesion was 29.3 in smokers of both Kiraiku and filter cigarettes and 17.3 in smokers of both Kiraiku and non-filter cigarettes. CONCLUSIONS: There was no statistically significant difference between the influence of filter and non-filter cigarettes on the risk of developing oral leukoplakia. The effect of Kiraiku on the risk of this lesion was stronger in filter than in non-filter cigarettes. However, the confounding effect of tobacco dose response parameters could not be ruled out.

Adolescent↗
PubMed1998

Geophagy, iron status and anaemia among primary school children in Western Kenya.

As part of a cross-sectional study among 156 primary school children (median age 13 years, range 10-18) in Western Kenya, geophagy was assessed through interviews. 114 (73.1%) of these children reported eating soil daily. Haemoglobin levels were determined in all 156 children and serum ferritin concentrations in 135. The mean haemoglobin (Hb) concentration was 12.7 g/dl, and median ferritin concentration 27.2 microg/l. Both the proportion of anaemic (Hb < 11.0 g/dl) and of iron-depleted (ferritin < 12 microg/l) children was significantly higher among the geophageous children than among the nongeophageous (9.6% vs. 0% anaemia; P = 0.037; 18.4% vs. 5.4% iron depletion; P = 0.046). Serum ferritin and haemoglobin concentrations were not correlated (r = 0. 13 5; P = 0. 100). Multiple regression analysis showed that geophagy, hookworm eggs per gram faeces and malaria parasite counts per microl blood were independent predictors of serum ferritin, when controlling for other helminth infections, age and sex, and socio-economic and educational background of the children's families and family size (y = 36.038-11.247(geophagy) -- 0.010(hookworm epg) + 0.001(malaria parasite counts); R2 = 0.17). Multiple regression analysis with haemoglobin as dependent variable and the same independent variables did not reveal any significant predictors. Analysis of the soil eaten by the children revealed a mean HCl-extractable iron content of 168.9 mg/kg (SD 44.9). Based on the data on the amounts eaten daily and this mean iron content, soil could provide on average 4.7 mg iron to a geophageous child (interquartile range 2.1-7.1 mg), which is equivalent to 32% of the Recommended Nutrient Intake (RNI) for girls (interquartile range 14-48%) or 42% of the RNI for boys (interquartile range 19-63%). Iron depletion and anaemia are associated with geophagy, but only serum ferritin concentrations were shown to be dependent upon geophagy in the regression model. From the cross-sectional data no inference about causality can be made. To clarify the possible causal relationships involved, longitudinal studies and iron-supplementation intervention studies are needed.

Adolescent↗
PubMed1997

Geophagy among school children in western Kenya.

A cross-sectional study was conducted among 285 school children aged 5-18 years in Nyanza Province, Western Kenya, to determine the prevalence of geophagy and the types and amounts of soil eaten. Stool samples were taken from a subsample of 53 (19%) and their silica content determined to compare the results with the reported geophagy. Geophagy was practised by 73% of the children. The prevalence decreased with age for both sexes up to age 15, then remained stable for girls between 15 and 18 years but continued to decrease for boys in that age range. Most children ate soil from the surface of termitaria; others preferred the edges of paths and gullies, material from the wall of huts, and a chalk-like, soft stone commonly found in the area. The soil was eaten dry and was occasionally ground, but not processed in other ways. All but 4 of the children practising geophagy reported to eat soil at least once daily. The median amount reported eaten was 28 g daily, ranging from 8 to 108 g. The reported amount of soil eaten daily was significantly correlated to the results of the stool silica determinations. Using the median of 1% silica of faecal wet weight as a cut-off point to distinguish geophageous children from non-geophageous, the examination of a single stool sample had a sensitivity of 76% and a specificity of 80% to detect a geophageous child compared to the interview method. The cultural context of geophagy and its potential health impact in terms of infection and nutrition need to be further investigated, and it is suggested that more school and community-based studies on geophagy in different societies should be undertaken.

Adolescent↗
PubMed1995

The association between oral leukoplakia and use of tobacco, alcohol and khat based on relative risks assessment in Kenya.

A case-control study was conducted to determine the significance of tobacco, alcohol and khat (Catha edulis) chewing habits in the development of oral leukoplakia among Kenyans aged 15 yr and over. In a house-to-house survey, 85 cases and 141 controls matched for sex, age and cluster origin was identified and compared for these risk factors. Smoking unprocessed tobacco (Kiraiku) with a relative risk (RR) of 10.0 (95% confidence interval (CI) = 2.9-38.4) and smoking cigarettes (RR = 8.4; 95% CI = 4.1-17.4) were the most significant factors. While the RR associated with smoking cigarettes alone was 4.5 (95% CI = 1.9-10.8), smoking of both products (RR = 15.2) suggested probable synergy or additive effects. Oral leukoplakia in 18 cases could not be attributed to smoking tobacco. Commercial beer, wines and spirits were relatively weak, but statistically significant, risk factors. Traditional beer, khat and chilies were not significantly associated with oral leukoplakia.

Adolescent↗
PubMed1995

Orofacial lesions as indicators of HIV/AIDS among dental patients in Kenya.

Despite an estimated prevalence of 3-5% of HIV infection in Kenya, little has been reported on the occurrence of oral lesions amongst the afflicted individuals. We report ten cases who presented with orofacial lesions and subsequent serological evaluation confirmed them seropositive. In the light of the numerous problems facing clinical staff in less developed countries, these findings underscore the significance of clinical identification of more probable HIV patients on the basis of orofacial signs. Continuing education with respect to HIV infection through wider dissemination of information on orofacial signs to clinical staff especially in the context of invasive care and containment of infection are recommended.

Adult↗
PubMed1995

Prevalence of oral mucosal lesions in a Kenyan population with special reference to oral leukoplakia.

The prevalence of oral leukoplakia and related lesions in a Kenyan rural population was determined in a systematic house to house survey of individuals aged 15 years and above. Among the 803 individuals examined, the following prevalence of lesions was observed: leukoedema (26%), melanosis (12.7%), leukoplakia (10.6%), palatal keratosis (6.4%), frictional keratosis (5.5%), pre-leukoplakia (4.1%), borderline leukoplakia (2.4%), cheek/lip biting (1.3%), and snuff dippers lesion (0.4%). 48.6% of the subjects had at least one of these lesions. Statistically significant preponderance was demonstrated for oralleukoplakia, palatalkeratosis, leukoedema and frictional keratosis among males and melanosis among females. With regard to clinical classification of oral leukoplakia, the prevalence was 10% for homogeneous and 0.6% for nonhomogeneous lesions. On the basis of aetiological classification; the prevalence was 8.3% for tobacco associated and 2.2% for idiopathic leukoplakia. 22.5% of leukoplakia lesions biopsied had evidence of epithelial dysplasia. In view of the premalignant potential of oral leukoplakia, our findings suggest a need for greater attention towards prevention and control of this lesion in the study community.

Adolescent↗
PubMed1994

Endemic fluorosis: an analysis of needs and possibilities based on case studies in Kenya.

The decline in prevalence of dental caries in the western world is largely ascribed to the protective role of fluoride in water. However, in several Third World regions, its presence in excessive amounts has been detrimental to the health of resident communities due to the resulting endemic dental and skeletal fluorosis. As a prelude to introduction of preventive intervention among the affected communities, there is need to assess knowledge and perception, and affordable and effective possibilities. The results of such an assessment which was based on response of mothers from two affected communities showed that objectionable dental fluorosis was not viewed as a common health problem in the context of other more common diseases. A reawakening of interest and concern was evident when issues pertaining to oral health were addressed. Dental fluorosis was viewed as an important problem because of its unfavourable effects on an individual's personality by between 60.4 and 84.3% of the respondents. While 60% and over of the respondents attributed the problem to water, knowledge on perceived methods of prevention of fluorosis were significantly lower. Only 12% of respondents from a relatively higher income group were instituting relevant preventive strategies. Although defluoridation of water had been instituted in one area, problems relating to wrong choice of water for defluoridation to inadequate distribution of the defluoridated water were evident. Education of the communities on methods of reducing fluoride ingestion and the significance of the defluoridated water, rationalizing the distribution of defluoridated water, facilitating collection of rain water, protection of available low fluoride surface water from contamination with agro-chemicals and household defluoridation were recommended.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Replacement therapy utilising autotransplanted wisdom teeth.

Loss of 1st and 2nd molars among adolescents due to dental caries is not uncommon in developing countries. Whilst their replacement is indicated, conventional methods of treatment, namely, bridging and dentures are in most cases inaccessible because of prohibitive cost. Given that it is in the same age group that diagnosis of unfavourably embedded wisdom teeth becomes feasible, autotransplantation of the latter to replace the unsalvageable 1st and 2nd molars could be an alternative treatment. Available literature suggests a success rate of over 82% based on follow-up studies of over ten years. Observations at the Dental School Clinic of the University of Nairobi, Kenya, indicate that the time it takes the transplant to 'take' and assume its functional position is 4 to 8 weeks and 2.5 to 3.5 months respectively. Since the method is relatively straightforward, we are of the view that training undergraduates and practising dental surgeons in this technique should enhance utilisation of otherwise "useless" teeth to replace the lost 1st and 2nd molars in occlusal rehabilitation.

Adolescent↗
PubMed1993

Biocidal effects and residual glutaraldehyde in cellulosic and synthetic polymers.

The amount of leachable glutaraldehyde from medical grade Cuprophan 150PM (cellulose based) and AN69S (a copolymer of acrylonitrile and sodium methallyl sulphonate) membranes, and polyproprene plates following 72 hr immersion in 2% alkaline glutaraldehyde was determined. After rinsing the materials for 30 minutes in distilled water at 37 degrees C, the mean concentration of leachable glutaraldehyde from Cuprophan 150 PM (8. 60 +/- 0.55 micrograms/g) was significantly greater than that from AN69S membrane (6.50 +/- 0.60 micrograms/g), (p < 0.01). The mean leachable glutaraldehyde from plates was 0.30 +/- 0.15 microgram/g. There was a significant decrease in the mean leachable glutaraldehyde from AN69S (5.35 +/- 0.25 micrograms/g) after second immersion (p < 0.05). The concentration of leachable glutaraldehyde in the plates and Cuprophan 150PM remained relatively unchanged. Absence of growth following infusion of 2% alkaline glutaraldehyde into blood contaminated miniature dialyzers containing high microbial loads of selected bioindicator organisms (S. aureus, P. aeruginosa, B. subtilis (Var globigii) spores, M. gordonae, A. niger spores and attenuated polio virus) demonstrated its effectiveness under environmental conditions that were conducive to high resistance. These findings indicate that 2% alkaline glutaraldehyde is readily washed from the three polymer materials that were studied and its accumulation following repeated exposure was not evident. Its application in pre-sterilization treatment of heavily contaminated invasive polymer based devices seemed feasible.

Acrylic Resins↗
PubMed1993

Fluoride and abrasive content in commonly used dentifrices on the Kenyan market.

About one decade ago, a heated debate on the appropriateness of fluoride dentifrices in Kenya culminated in the introduction of no-fluoride brands. Analysis of dentifrices that were available on the market in 1989/1990 confirmed two distinctly different categories, the fluoride and the low or no-fluoride types. Among the former, the mean ionic fluoride concentration ranged between 0.4 and 1.36 mg/g while the total fluoride concentration ranged between 1.15 and 114.68 mg/g. The low or no-fluoride dentifrices had less than 0.03 mg/g ionic fluoride and less than 2.14 mg/g total fluoride. The mean abrasive (powder) content ranged between 26.5 g% and 78.5 g%. The gel categories had markedly lower powder values than the pastes. The ash values of the powders ranged between 15.8 g% and 85 g% and did not have an obvious relationship with the powder content. Despite the obvious risk of increasing exposure to excessive fluoride among children, presently, the situation has reverted to the pre-debate time. Given the ubiquitous nature of ingestable fluoride in the region, provision of guidelines and guidance on the sale of dentifrices by the government and consumer organisations, and increased accountability of the manufacturers are recommended.

Data Collection↗
PubMed1992

Fluoride sorption characteristics of different grades of bone charcoal, based on batch tests.

Although bone charcoal (char) has been recommended for use in the de-fluoridation of drinking water in developing countries, parameters relating to fluoride (F) sorption characteristics by grade or type of bone char are unclear. Based on batch tests, the rate and capacity of F uptake were highest with black grade, followed by grey grade and lowest with white grade. Twenty-four-hour contact-time F sorption isotherms indicated saturation at capacities of 11.4 mg F per g of black grade, 2.4 mg F per g of grey grade, and less than 0.3 mg F per g of white grade bone char. Additional investigations showed that F-removal efficiency of black grade char decreased steadily with increasing F concentration. Its initial sorption kinetics were dependent on particle size, and the highest sorption rate was observed with particle sizes below 0.42 mm. For maximum sorption rate, the critical mixing time was between five and 15 min. The presence of chloride anions and elevated temperatures increased the rate of F uptake by black bone-char. The pH of distilled water following contact with bone char rose to 11.5 for white bone-char, 8.3 for grey bone-char, and 7.8 for black bone-char. The effects of processing temperature on the availability of intra- and extra-apatitic F-binding sites, levels of oxides of calcium and magnesium, and the carbon content were viewed as possible causes of observed variations. These findings suggest that the black grade of bone char was the most efficacious for use in partial de-fluoridation of drinking water.

Absorption↗
PubMed1992

A retrospective study of characteristics of impacted mandibular wisdom teeth in 110 patients treated in Nairobi, Kenya.

Analysis of 110 records of patients who presented with impacted mandibular 3rd molars was carried out to determine the frequency of occurrence of unilateral and bilateral impactions and their characteristics. 68.2% of the patients had bilateral impactions. Among the patients with bilateral impactions, 72% had mesioangular impaction occurring either bilaterally or in combination with other types of impaction. Furthermore, 38.7% mesioangular impactions were observed on the right and left sides in the patients with bilateral impactions. Among the patients with unilateral impactions 40.2% presented with mesioangular impaction, while 25.7% presented with distoangular impactions. While these observations support the general consensus regarding aetiology of mandibular 3rd molar impactions as being tooth-tissue discrepancy, the possible influence of other factors is suggested.

Adult↗
PubMed1992

Assessment of blood compatibility of haemodialysis membranes using a miniature flat sheet dialyser.

Available pre-clinical techniques of assessing severity of untoward reaction by blood following contact with haemodialysis membranes do not account for the effects of dialysate and flow characteristics in the observed blood changes. A miniature flat sheet dialyser that considered these effects was prepared and tested in both in-vitro and ex-vivo circuits. Changes in platelets and leucocytes in heparinised human blood in-vitro tests did not distinguish regenerated cellulose (Cuprophan 150PM) membrane from a synthetic membrane, a copolymer of acrylonitrile and sodium methyl sulphonate (AN69S). Ex-vivo tests using rats showed more marked leucocyte (41.3%) and platelet (43.1%) depletion by Cuprophan 150PM than AN69S after 90 minutes of dialysis. Leucocyte and platelet loss due to AN69S were 26.9% and 13.4% respectively. In addition, Cuprophan 150PM membranes exhibited high affinity for leucocytes and platelets in both in-vitro and ex-vivo tests compared to AN69S membranes which were primarily covered with erythrocytes. Application of simulated in-use techniques in preclinical evaluation of blood compatibility membranes that are used in extra-corporeal treatment are recommended.

Acrylic Resins↗
PubMed1992

Coping with embedded mandibular wisdom teeth in developing countries.

Despite low incidence of embedded mandibular wisdom teeth (third molars) among dental patients in developing countries (less than 100/1,000), the unfavourable patients:dentist ratios, the limited resources and low levels of public awareness render them an important problem to operators in these countries. Since the effectiveness with which they are removed largely depends on the age with respect to the stage of root formation, bone resilience and relationship with adjacent anatomical structures, and the dexterity of the operator, whenever possible, early removal is recommended. To minimise occurrence of non-operative complications that are costly to manage, primary health care workers have a vital role to play in raising levels of awareness and early referral for further evaluation. In view of the risks involved in the removal of these teeth and the small number of trained oral surgeons, continuing education to the dental practitioners, could improve their efficiency in the management of this condition.

Developing Countries↗