Kenyan Population Research Articles

Validity of CPITN's assumptions of hierarchical occurrence of periodontal conditions in a Kenyan population aged 15-65 years.

In order to study the validity of the hierarchical principle of the CPITN we used data originating in a cross-sectional study of periodontal disease in a random sample comprising 1131 Kenyans aged 15-65 yr to determine, for each tooth present in each individual, the absence or presence of gingival bleeding, of dental calculus, of a pocket of 4-5 mm or a pocket of 6+ mm, such that each tooth had a separate recording for bleeding, calculus, pocket 4-5 mm and pocket 6+ mm. According to the hierarchical principle of CPITN a tooth with pockets as the most severe finding is assumed positive also for calculus and bleeding, and a tooth with calculus as the most severe finding is assumed positive also for bleeding. Our analysis showed that calculus as the most severe finding of a tooth overestimates the occurrence of bleeding by up to 18%, depending on age of the individuals and the set of teeth examined. Pockets as the most severe finding in a tooth overestimates the occurrence of bleeding by up to 13%, and overestimates calculus by up to 54%, most pronounced in the younger age groups. The effect of these overestimations on prevalence and severity estimates was the most pronounced for the severity measures, particularly regarding the severity of bleeding, whereas prevalence estimates remained relatively unaffected. Undoubtedly, this result should be seen in the light of a very high prevalence and severity of both bleeding and calculus in this population.

Anterior tooth relations in Kenyan Africans

Dental plaster casts of 235 Maasai, 116 Kikuyu and 61 Kalenjin children aged 3–16 yr were studied to determine the incidence and magnitude of diastemas, overbite, overjet and anterior open bite. The highest prevalence of diastema was amongst the Maasai (61.3%), of overbite (84%) and overjet (99%) amongst the Kikuyu, and of anterior open bite amongst Kalenjin (24%), with values greater than 0.4 mm up to 11.5mm. Comparison of the mean values showed that diastema (1.77mm) and overjet (4.4mm) were greatest in Maasai, overbite (3.53 mm) in Kalenjin, and anterior open bite (3.50 mm) in Kikuyu. In the total sample, the prevalence and mean of diastema were 49%, 1.68 mm; of overbite 77.4%, 2.96 mm; of overjet 88.6%, 3.83 mm; and of anterior open bite 16.5%, 2.69 mm (with values between 0.4–11.5 mm), while 5.5% had an edge-to-edge bite (−0.5-0.5 mm). The prevalence of diastema decreased whilst its magnitude increased with age. The mean values of overbite and overjet increased, while those for anterior open bite decreased with age. The mean values of diastema, overbite and overjet were greater amongst the females, but the difference was significant only for overjet. The high prevalence and greater values of measurements of anterior tooth relations may be related to variable growth of the bimaxillary dentoalveolar complex and soft tissue influences. This may be important in orthodontic treatment planning, dental prostheses and other clinical dental treatments in Kenyan populations.

Genetic variability and gene flow in geographical populations of Ceratitis capitata (Wied.) (medfly)

Two African populations of Ceratitis capitata (Kenya and Réunion Isl.) and two Mediterranean ones (Sardinia and Procida Isl.) have been studied for genetic variability at 25 loci by electrophoresis. Wright's FST, Slatkin's Nm* gene flow estimator, Nei's distance (D) together with measures of variability such as H, P, A have been used to compare the population from Kenya with the other three. Parameters using gene frequencies (FST, D, Nm*) indicate the presence of substantial geographic heterogeneity, largely attributable to genetic drift and correlated with dispersion of the medfly from its source area (Subsaharan Africa) to the periphery. The Kenyan population has high genetic variability (assessed by H, P and A), as might be expected given its native status. Significant gene flow estimates between Kenya and the derived Mediterranean populations supports the hypothesis of recent colonization. Part of the geographic heterogeneity is related to the presence of fixed alleles in the more differentiated Réunion population although it maintains the genetic attributes of the ancestral population. Selection or other forces may have played an important role in the differentiation of this population.

FRESHWATER SNAILS OF THE BULINUS TRUNCATUS/TROPICUS COMPLEX (BASOMMATOPHORA: PLANORBIDAE) IN KENYA: DIPLOID POPULATIONS

Freshwater snails of the Bulinustruncatus/tropicus complex occur in Kenya as diploid and tetraploid forms which may not noticeably differ in the shell. This account provides data for diploid snails, on geographical distribution, inter-population variation, taxonomy and identification. Observations were made for 65 populations (40 newly reported) on egg proteins, body surface mucus, enzymes (5 systems), shell (10 variables), male genital system (normal or aphallic) and radula (1st lateral tooth; size and meso-cone shape). Two snail populations sampled were known to carry the trematode parasites Schistosoma bovis and Calicophoron microbothrium. All the diploid populations sampled appeared con-specific from their overall continuity in morphological variation and its lack of geographical pattern, and the observation of interbreeding between snails of contrasting morphology. On the other hand, there were considerable interpopulation differences in shell form, mesocone shape and enzymes. A distinct shell form (corresponding to Physa rumrutiensis Preston) is associated with seasonal rainpools. Some Kenyan populations have the mesocone commonly angular in shape, in this respect resembling B. natalensis. The entire range of forms is here classified as B. tropicus, but future subdividing of this taxon is not unlikely. Reasons are advanced for regarding as diploid, taxa of Bulinus named by Dautzenberg (alluaudi) and by Preston either validly (exserta, laikipiaensis, rumrutiensis, syngenes) or in manuscript(baringoensis, congener). The status of the taxa B. natalensis and B. zanzebaricus is discussed. Morphometry did not reveal any clear difference by which all forms of B. tropicus could be separated from both the tetraploid species B. truncatus and B. permembranaceus. Each species does have characteristic enzyme types (AcP, HBDH, MDH and GPI). B. tropicus is widely distributed in Kenya and is common in some areas where other species of Bulinus are rare or absent, but it is surprisingly not found in the coastal region.

Moderate iodine deficiency, a possible explanation for the inverse relationship between cord serum thyrotropin and birth weight in a normal Kenyan population.

Moderate iodine deficiency, a possible explanation for the inverse relationship between cord serum thyrotropin and birth weight in a normal Kenyan population.

Concentrations of thyroid hormones in maternal and cord blood from a normal Kenyan population.

Concentrations of thyroid hormones in maternal and cord blood from a normal Kenyan population.

Associations between dermatoglyphic variation, topography, and climate in Kenya.

Correlations between a number of dermatoglyphic finger and palmar taxonomic traits relating to 57 male and 53 female Kenyan populations, and altitude and mean annual rainfall are significant, not only in terms of the full range of samples, but also when samples are divided into independent smaller groups. These results are discussed and contrasted with those of other studies which have found no relationships between dermatoglyphic variation and climate in sub-Saharan Africa.

Migration-induced changes in blood pressure: a controlled longitudinal study.

A longitudinal study of the effects of migration on blood pressure and related factors is being carried out in members of a black Kenyan population who migrate from a traditional rural community to an urban environment. Data on the first 139 migrants (78 male, 61 female) and 204 control non-migrants (126 male, 78 female) who have been followed up for a period of 6 months are presented. Blood pressure changes rapidly on migration (within the first 2 months); thereafter trends between migrants and controls differ. Significant differences in systolic pressure between migrants and controls are found at all examinations during the 6 month follow-up in both sexes. Diastolic pressure falls in controls but rises in migrants, the greatest difference being seen at the 6 month examination. Migration is associated with a marked increase in dietary sodium and a fall in potassium demonstrated by measurements of urinary electrolyte excretion in 3 X 12 h or 3 X 24 h urine collections. Analysis of covariance shows that the blood pressure differences between migrants and controls are partly explained by urinary sodium/potassium ratios and in some instances by body weight.

Non-specific cell mediated immunity in patients infected with Schistosoma mansoni in Kenya

Parameters of in vitro cell-mediated immunity (CMI) have been measured in the local Kenyan population infected with Schistosoma mansoni. Lymphocyte responses to the non-specific T cell mitogens Concanavalin A (Con A) and Phytohaemagglutinin (PHA) were reduced in about 60% of schistosomiasis patients. Lymphocytes from control uninfected, and S. mansoni-infected donors formed equal numbers of spontaneous rosettes with sheep red blood cells, indicating that there was no over-all reduction in the percentage numbers of T cells in the schistosomiasis patients.

Absence of palmar triradius d in a series of Kenyan samples.

SummaryThe absence of primary triradius d on the human palm is an extremely rare dermatoglyphic feature. At one time its recorded occurrence was confined to a few abnormal males. Recently, however, the feature has been unambiguously identified in normal individuals of both sexes (Holt and Dash Sharma 1977): in one English female student, in two sisters from the Nicobar Islands and on five male and three female Tibetan palms.The present paper confirms the existence of ‘missing d’ in Kenyan populations. Out of a sample of 3552 males and 2678 females, 13 males and 15 females displayed the feature on a total of 31 palms. These occurrences are all, except for one unusual case which is illustrated, classic examples of the absence of d. Cases of ‘shifting’ and zygodactylous triradii that could be confused with the classic type in so far as they can also manifest the absence of d from its normal position, are all excluded from the survey. Methodological issues surrounding the identity and nomenclature of such fea...

"Geographic" Variation in Sensitivity to X-Irradiation in Tribolium: II. Incidence of Developmental Abnormalities

Induction of developmental abnormalities was studied after x-irradiation of two-day-old pupae of various geographic populations of Tribolium castaneum and T. confusum. Canadian populations were the most sensitive; 21.1% showed the split wing abnormality in T. castaneum, and 37.5% showed this in T. confusum. Kenyan populations were the most resistant. They showed 1.0% abnormalities in T. castaneum and 16.7% in T. confusum. In general, T. castaneum was more resistant than T. confusum with 5.5% and 18.6% split wing abnormalities being produced, respectively. Length of the pupal stage was studied in T. castaneum. The pupal period decreased with increasing age at which larvae pupated. Emerged adults after irradiation had shorter pupal periods than their controls. This finding is contrary to earlier records, by other investigators, on eclosion delay using lower doses of x-irradiation and different pupal ages. Choice of dose, criteria, and consideration of the consequences of the choice of age at exposure are ...

Compositional variation of leaf pocket sesquiterpenes in Trachylobium verrucosum

Greenhouse-grown plants originating from Kenyan and Madagascan populations of Trachylobium verrucosum are qualitatively identical in leaf pocket resin sesquiterpene composition, but differ quantitatively.

Cross-National Dimensions of Ethnocentrism

The effects of ethnocentric attitudes had plagued man's relations to his fellows long before Summer gave an academic explication of the phenomenon in 1906.1 The apparent universality of the attitude has been confirmed by subsequent scholars 2 at the same time that the fluidity and relativity of perception of in-group versus out-group became increasingly apparent.3 In the African context it is more usual to refer to tribalism but given the often acrimonious debate over the use of that term, this discussion will use the more neutral word, ethnocentrism. Its use will serve to remind us that the same questions can be asked of our own particularisms in Europe and North America. While there are many aspects of the general phenomenon of ethnocentrism that could be probed, the data available here permits only an examination of the patterns of ethnocentrism in two African nations, some comparisons of the two national patterns and an investigation of some correlates that reflect differing socialization experiences. The implications of differing intensities of affect-dislike between various component tribal groups in the Ghanaian and Kenyan populations are of considerable social importance, even aside from the political uses to which they can be diverted. An integration problem per se is created for a nation if some

Oviposition of Tribolium in Static Environments Incorporating Controlled Temperature and Humidity Gradients

The oviposition of Nigerian (ex Umuahia), Jamaican (ex Kingston) and Kenyan (ex Nairobi) populations of Tribolium castaneum (Herbst), and a laboratory population of T. destructor Uytt., was studied in static environments incorporating controlled, linear gradients of temperature and humidity. By selecting the level of humidity (high or low) operating over identical temperature gradients, the adult distribution could be altered on the temperature scale. Moreover, it also affected the total number of eggs laid and altered the shape and caused considerable drifts in the entire egg distribution. The oviposition zone in terms of temperature and relative humidity is consequently a function of the total environment to which the ovipositing adults have had access. Any variation in this total environment may thus produce an altered oviposition zone. Differences in adult distribution and oviposition site were observed between species and also between populations of the same species.

Variant anatomy of the testicular artery among black Kenyans

Variant anatomy of the testicular artery is important for safe surgery in the retroperioneal area, and accurate diagnosis of testicular and renal disease. The pattern of origin, number, course and branching display ethnic and geographical variations. Data from black African populations and especially Eastern Africa is scarce. The objective of this study was, therefore, to describe the topography of the intraabdominal part of testicular artery in a sample of the Kenyan population. This was a descriptive crosssectional study on one hundred (100) testicular arteries at the Department of Human Anatomy, University of Nairobi. The samples were obtained from autopsy cases and cadaveric specimens. Standard midline abdominal incisions were made, flaps of the anterior abdominal wall reflected and the intestines, mesentery and pariental peritoneum retracted systematically to expose the testicular arteries. Their site and level of origin, number, course and branching were examined. Macrographs of representative variations were taken using a high resolution digital camera. The results were analysed using SPSS version 21, and are presented using macrographs and frequency tables. Thirty three (33%) of the arteries displayed a variant anatomy, with regard to their site of origin (8%), number (4%), course (14%) and branching pattern (7%). Among the 14 cases of aberrant course, five (5%) arched over the left renal vein, eight (8%) were retrocaval and one (1%) had a retroureteric course. Seven (7%) bifurcated within the abdomen. The level of origin along the aorta varied from 1 centimetre above the renal arteries to 5.5 centimetres below them while the vertebral level of origin ranged from T12 to L4. This shows that the testicular artery among Kenyans displays a high prevalence of variant anatomy characterized by origin from the accessory renal artery, high level of aortic origin, duplication, retrocaval course and intraabdominal; division. Preopertaive evaluation of renal and gonadal vasculature is recommended to minimize misdiagnosis and inadvertent injury retroperitoneal surgery.