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Genetic polymorphism of CYP2D6 and CYP2C19 in east- and southern African populations including psychiatric patients.

OBJECTIVES: The study was carried out to investigate the distribution of cytochrome P450 2D6 (CYP2D6) and CYP2C19 genotype frequencies in three African populations and to compare these frequencies between healthy individuals and psychiatric patients. METHODS: Three hundred and eighty-four subjects from South Africa (Venda), Tanzania, and Zimbabwe who consented to the study were genotyped for CYP2D6 (CYP2D6*1, *2, *3, *4, *5, and *17) and CYP2C19 (CYP2C19*1, *2, and *3) by PCR-RFLP (polymerase chain reaction restriction fragment length polymorphism) techniques. RESULTS: The genotypes for CYP2D6 predicted a poor metabolizer frequency of 2.3% (2/88) in Tanzanian psychiatric patients, 1.9% (2/106) in Tanzanian healthy controls and 2.6% (2/76) in the South African Venda. The low-activity CYP2D6*17 allele frequency was higher in psychiatric patients (30%, 53/176) than in healthy individuals (20%, 43/212) in Tanzanians. The frequencies for CYP2C19*2 genotypes were predictive of a low prevalence of poor metabolizers (PMs). The CYP2C19*3 allele was absent in the three populations studied. There was no difference in CYP2D6 or CYP2C19 PM genotype frequencies between psychiatric patients and healthy subjects. CONCLUSION: The genotype results predict a low prevalence of people with deficient CYP2D6 and CYP2C19 activity among linguistically (Bantu) related populations of East and Southern Africa. The high frequency of the low-activity CYP2D6*17 allele predicts that the Bantu people have a reduced capacity to metabolise drugs that are CYP2D6 substrates.

Adolescent↗

Patterns of genetic diversity and differentiation in the tsetse fly Glossina morsitans morsitans Westwood populations in East and southern Africa.

Genetic diversity and differentiation within and among nine G. morsitans morsitans populations from East and southern Africa was assessed by examining variation at seven microsatellite loci and a mitochondrial locus, cytochrome oxidase (COI). Mean COI diversity within populations was 0.63+/-0.33 and 0.81 taken over all populations. Diversities averaged over microsatellite loci were high (mean number of alleles/locus>or=7.4; mean HE>or=65%) in all populations. Diversities averaged across populations were greater in East Africa (mean number of alleles=22+/-2.6; mean he=0.773+/-0.033) than in southern Africa (mean number of alleles=18.7+/-4.0; mean he=0.713+/-0.072). Differentiation among all populations was highly significant (RST=0.25, FST=0.132). Nei's Gij statistics were 0.09 and 0.19 within regions for microsatellites and mitochondria, respectively; between regions, Gij was 0.14 for microsatellites and 0.23 for mitochondria. GST among populations was 0.23 for microsatellite loci and 0.40 for mitochondria. The F, G and R statistics indicate highly restricted gene flow among G. m. morsitans populations separated over geographic scales of 12-917 km.

Africa, Eastern↗

Rapid Agrobacterium-mediated transformation and high-efficiency regeneration of finger millet (Eleusine coracana) for crop improvement.

Finger millet (Eleusine coracana) is a nutritionally important and climate-resilient cereal cultivated in rainfed regions of India and Eastern Africa, yet its genetic improvement has been limited by the lack of efficient and reproducible transformation systems. In this study, we developed a rapid and efficient Agrobacterium tumefaciens-mediated transformation and regeneration system using shoot apical meristem (SAM) explants, enabling direct, callus-free shoot organogenesis. Optimal regeneration and shoot elongation were achieved on Murashige and Skoog (MS) medium supplemented with 3.5 mg L⁻1 6-benzylaminopurine (BAP), 1.5 mg L⁻1 kinetin, 0.1 mg L⁻1 2,4-dichlorophenoxyacetic acid (2,4-D), and 0.2 mg L⁻1 gibberellic acid (GA₃). Genotype-dependent responses were observed, with PR-202 requiring 2 mg L⁻1 AgNO3 to reduce phenolic browning, whereas VL-376 regenerated efficiently without AgNO3. Transformation efficiencies of 30-32% were achieved in PR-202 and VL-376, respectively, by optimising infection and co-cultivation conditions, including reduced MS salt strength and pre-incubation of Agrobacterium. Molecular analyses, including PCR and Southern blot hybridisation, confirmed stable T-DNA integration in independent lines, while segregation analysis of T₁ progenies demonstrated Mendelian inheritance of the transgene. In addition, CRISPR/Cas9 constructs targeting EcCKX2 were successfully introduced via Agrobacterium, demonstrating the suitability of this system for genome engineering applications. Overall, this optimised SAM-based protocol provides a rapid (45-50 days), efficient, and reproducible platform for stable genetic transformation in finger millet and establishes a strong foundation for transgenic research and future genome editing studies in this underutilized crop.

Eleusine↗

Coronary heart disease and coronary disease risk factors in black populations in underdeveloped countries: the case for primordial prevention.

Coronary heart disease (CHD) is relatively rare in black populations in Africa and is a much less significant cause of morbidity and mortality in black populations in the Caribbean than in U.S. blacks. The incidence of CHD appears to be increasing in segments of some black populations in underdeveloped countries, concurrently with certain patterns of socioeconomic change. Hypertension, hypercholesterolemia, and cigarette smoking are not as common in most of these black populations as in white populations in industrialized countries, although certain affluent groups in African and Caribbean countries have higher levels of some of these risk factors than do the rest of the population. Moreover, the impact on CHD of these risk factors, especially hypertension, appears to be less than is observed in industrialized countries. The absence of mass hyperlipidemia probably accounts for the lower prevalence and incidence of CHD. A policy of primordial prevention of CHD, by control of risk factors and preemptive action to prevent their establishment in the population, has been recommended to Third World governments by a World Health Organization Expert Committee. The need for such a policy, and its applicability in black populations in Africa and the Caribbean, are limited by their socioeconomic situations. Thus for practical purposes, the deteriorating economic situation in the low-income countries (the majority) of sub-Saharan Africa and the Caribbean restricts the possibilities of adverse risk factor changes. In particular, the widespread assumption of the food consumption patterns typical of industrialized countries and the development of mass hyperlipidemia are effectively prevented. In contrast, attempts to foster or maintain desirable food consumption patterns are warranted in middle-income African and Caribbean countries, especially among newly affluent minorities. In all of these territories, primary prevention of hypertension, especially in urban populations, is the ideal approach to the primordial prevention of cardiovascular diseases, of which CHD is a small component.

Adolescent↗

A comparison of the isoenzymes of Trypanosoma (Duttonella) vivax isolates from East and West Africa.

The genetic diversity in 13 stocks and clones of Trypanosoma vivax from East and West Africa was compared by isoenzyme analysis. The Ugandan and West African stocks and clones showed a very high degree of genetic similarity to each other but they differed from the Kenyan stocks and clones. Two haemorrhagic stocks, IL 2337 (Galana, Kenya) and IL 3067 (Bamburi, Kenya), showed a high degree of similarity in enzyme banding patterns in electrophoresed preparations. One of the Kenyan stocks, M1D 627, differed in most of its enzyme banding patterns from all the other stocks and clones used.

Africa, Eastern↗

The distribution of enzyme variation in populations of Plasmodium falciparum in Africa.

Isolates of Plasmodium falciparum collected from the east and west coasts of tropical Africa and also from several inland regions have been examined for electrophoretic forms of the enzymes GPI, LDH and 6PGD. Variation within and between isolates was found in the parasite forms of all three enzymes. While not disproving the existence of genetic divisions between P. falciparum populations in Africa the distribution of this variation provides no evidence for such a hypothesis.

Africa, Eastern↗

Comparison of the physiological effects in rabbits of gaboon viper (Bitis gabonica) venoms from different sources.

The cardiovascular, respiratory and metabolic effects of B. gabonica venoms obtained from specimens originating from Ghana, Togo, Nigeria, Uganda and Tanzania were examined in anaesthetized rabbits. Intravenous injection of all venoms (0.125-2.0 mg/kg) induced hypotension. Nigeria venom was the least potent in this respect. Following doses of all venoms there was a brief bradycardia and a transient increase in respiratory rate and depth. At high doses (greater than or equal to 1.0 mg/kg), all venoms induced severe ST depression and T wave inversion. In addition, Togo venom, and to a lesser extent Tanzania and Ghana venoms, were potent in inducing extrasystoles. None of the venoms produced any significant changes in haematocrit, plasma proteins or arterial blood gas and pH levels. All venoms increased blood glucose and lactate levels by 1.3-2.1 fold and 2.2-4.0 fold respectively while the respiratory quotient remained unchanged. Togo venom was significantly (P less than 0.05) more lethal than the other venoms. The pattern of haemorrhage observed at post-mortem was the same for all venoms with the heart, ureters, adrenals, kidneys, lungs, stomach and intestines being the most affected. When combined on a subspecies basis, the results suggest that there are no significant differences in the physiological effects of venoms representing B. g. rhinoceros (West African gaboon viper) and B. g. gabonica (East African gaboon viper).

Africa, Eastern↗

Recombinant DNA probes reveal simultaneous infection of tsetse flies with different trypanosome species.

The utility of recombinant DNA probes in the detection of natural trypanosome infection of tsetse flies has been assessed in Lambwe Valley, near the shores of Lake Victoria, Kenya. The tsetse flies were surveyed during two different seasons in 1988. Three different probes used each contained highly repetitive DNA sequences specific for a species or subspecies of trypanosomes of the Nanomonas subgenus. A fourth probe contained repetitive sequences common to trypanosome species of the Trypanozoon subgenus. Mixed mature or immature infections were detected in a variety of combinations in different individual tsetse flies. Such infections were detected in both the guts and mouthparts of some tsetse flies. Simultaneous natural infection of tsetse with the savannah type Trypanosoma congolense and Kilifi type T. congolense, T. congolense and Trypanosoma brucei or T. congolense and Trypanosoma simiae were demonstrated. The probes have thus been used to demonstrate the presence of Lambwe Valley, south-western Kenya, of a type of T. congolense first observed among trypanosome isolates obtained from sentinel cattle exposed to natural infection on a ranch at Kilifi on the Kenya coast. This type of T. congolense appears not to be confined to the coastal region nor to any particular species of tsetse flies and may contribute significantly to livestock morbidity in other areas of eastern Africa. In the Kilifi area, T. congolense was found primarily in Glossina austeni; in Lambwe valley, it was found in Glossina pallidipes.

Animals↗

The diffusion of influenza in sub-Saharan Africa during the 1918-1919 pandemic.

The focus of this study is the spread of influenza in Africa south of the Sahara during the pandemic of 1918-1919. Most known types of diffusion pattern, i.e. radial, wave-like and linear, have been identified; however, the disease spread to rapidly that four particularly devastating linear patterns stand out. One of the most incredible aspects of the regularity in epidemic velocity along these pathways was that the colonial transportation network was of fairly recent origin. Given modern transportation linkages, the ever-present danger of the resurgence of the agent or agents that caused the pandemic could result in a much greater disaster in Africa and other Third World areas if unabated by effective inoculation programs.

Africa, Eastern↗

Nutrition and the commoditization of food in sub-Saharan Africa.

During the past decade, Africa, more than any other continent, has been associated with famine and malnutrition. The Sahelian drought of the early 1970s, the Wollo and Karamoja famines and most recently, mass starvation in Ethiopia, have followed one another in rapid succession. The term 'food crisis' continually crops up in the popular and academic press. An increasing number of researchers probe possible causes; many seek a systemic reason for the present situation. One working hypothesis is that increasing commoditization of food has undermined Africa's food systems. This paper does not purport to prove or disprove this. Less ambitiously, its aim is to draw attention to inter-relationships between commoditization and physical and social aspects of African food systems, tracing their possible effects on the nutritional status of the African population. In so doing, some of the complexities of developing food production and consumption in the transition from peasant societies to more urban-based national economies become evident. The paper is divided into three main parts: a discussion of conceptual categories and general background information about sub-Saharan African food zones and commodity and factor markets; a review of literature on rural food availability and nutrition; and a review of urban food availability and nutrition.

Africa, Central↗

Industrial production, health and disease in sub-Saharan Africa.

Industrial development in Africa has carried with it significant health costs. These costs are normally defined rather narrowly by those concerned about occupational or industrial health and safety and refer only to the health consequences of worker exposure to specific hazardous processes, materials or environmental conditions associated with the workplace. A more comprehensive measurement of industrial health costs, however, must also include an assessment of the impact which industrial development and the creation of an industrial workforce has on ecological relationships, environmental conditions and patterns of sickness and health in the areas surrounding industrial centers. Traditional definitions of occupational health also tend to focus attention on the immediate causal linkages which exist between the development of particular industrial processes and specific health hazards. Yet any attempt to fully understand the causes of industrial health problems in Africa must look beyond these immediate causal linkages and examine the wider political and economic forces which determine the shape of industrial development and the extent to which the health costs of this development are borne by industrial workers and their families, as well as by people who may not be directly or even indirectly connected to industrial development, but may, nonetheless, be exposed to its health risks. The paper surveys the direct and indirect health costs of mining, large scale agriculture, and manufacturing in Africa and examines the economic and political interests which have determined the distribution of these costs.

Africa, Central↗

The competing discourses of HIV/AIDS in sub-Saharan Africa: discourses of rights and empowerment vs discourses of control and exclusion.

The competing discourses of HIV/AIDS circulating in sub-Saharan Africa are identified. These are medical, medico-moral, developmental (distinguishing between 'women in development' and gender and development perspectives), legal, ethical, and the rights discourse of groups living with HIV/AIDS and of African pressure groups. The analytical framework is that of discourse analysis as exemplified by Michel Foucault. The medical and medico-moral are identified as dominant. They shape the perceptions of the pandemic, our responses to it, and to those living with HIV/AIDS. However, dissident activist voices are fracturing the dominant frameworks, and are mobilising a struggle for meaning around definitions of gender, rights, and development.

Acquired Immunodeficiency Syndrome↗