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African Populations (african + population)
Kinds of African Populations Selected AbstractsIntellectual Disability in the Context of a South African PopulationJOURNAL OF POLICY AND PRACTICE IN INTELLECTUAL DISABILITIES, Issue 2 2008Jennifer Kromberg Abstract, Childhood disabilities, including intellectual disabilities (ID), are thought to occur in 5,17% of children in developing countries around the world. In order to identify and describe the childhood disabilities occurring in a rural South African population, as well as the context in which they occur, a study was carried out in the Bushbuckridge district in the poor northeast part of the country. Altogether, 6,692 children were screened in their homes in eight villages using the Ten Questions questionnaire. This questionnaire was used by local-trained field-workers in interviews with mothers and other carers, to screen children for five disorders (viz., intellectual, hearing, visual and movement disorders, and epilepsy). Altogether, 722 (10.8% of the total sample) children, who screened positive, were examined at clinics in their villages by a pediatrician for diagnostic, treatment, and referral purposes. In addition, 100 traditional healers in the district were interviewed with a specially designed schedule of questions to assess their attitudes toward disabilities and their management of affected children. The results showed that 291 (4.3%) children had at least one of the five disabilities. ID occurred in 3.6%, epilepsy in 0.7%, visual disorders in 0.5%, movement disorders in 0.5%, and hearing disorders in 0.3%. More boys than girls with hearing disorders were receiving special education. Many of the affected children were not receiving treatment or education, resulting in a reduction in their quality of life. Traditional healers were attempting to treat epilepsy and seldom referred affected children to hospital, although effective treatment was available there. Genetic factors were involved in about half the conditions, but genetic services were negligible. Appropriate health, diagnostic, treatment, educational, and supportive services are required for children with disabilities, and awareness of their needs and the resources to meet them should be increased in this community. [source] Genetic Diversity of the Fragile X Syndrome Gene (FMR1) in a Large Sub-Saharan West African PopulationANNALS OF HUMAN GENETICS, Issue 4 2010Emmanuel K. Peprah Summary Fragile X syndrome (OMIM #300624) is caused by the expansion of a CGG trinucleotide repeat found in the 5, untranslated region of the X-linked FMR1 gene. Although examinations of characteristics associated with repeat instability and expansion of the CGG repeat upon transmission from parent to offspring has occurred in various world populations, none has been conducted in large Sub-Saharan African populations. We have examined the FMR1 CGG repeat structure in a sample of 350 males drawn from the general population of Ghana. We found that Ghanaians and African Americans have similar allele frequency distributions of CGG repeat and its flanking STR markers, DXS548 and FRAXAC1. However, the distribution of the more complex marker, FRAXAC2, is significantly different. The haplotype structure of the FMR1 locus indicated that Ghanaians share several haplotypes with African Americans and Caucasians that are associated with the expanded full mutation. In Ghanaians, the majority of repeat structures contained two AGG interruptions, however, the majority of intermediate alleles (35,49) lacked AGG interruptions. Overall, we demonstrate that allelic diversity of the FMR1 locus among Ghanaians is comparable to African Americans, but includes a minority of CGG array structures not found in other populations. [source] Elucidation of CYP2D6 Genetic Diversity in a Unique African Population: Implications for the Future Application of Pharmacogenetics in the Xhosa PopulationANNALS OF HUMAN GENETICS, Issue 4 2010Galen E. B. Wright Summary Genetic variation of the CYP2D6 gene has been associated with altered drug metabolism; however, limited studies have investigated CYP2D6 sequence diversity in African populations. We devised a CYP2D6 genotyping strategy to analyse the South African Xhosa population and genotype a Xhosa schizophrenia cohort, as CYP2D6 metabolises many antipsychotics and antidepressants. The entire CYP2D6 gene locus was sequenced in 15 Xhosa control individuals and the data generated were used to design a comprehensive genotyping strategy. Over 25 CYP2D6 alleles were genotyped in Xhosa controls and Xhosa schizophrenia patients using long-range PCR, DNA sequencing and single nucleotide primer extension analysis. Bioinformatic algorithms were used to predict the functional consequences of relevant mutations and samples were assigned CYP2D6 activity scores. A unique allele distribution was revealed and two rare novel alleles, CYP2D6*73 and CYP2D6*74, were identified. No significant differences in allele frequencies were detected between Xhosa controls and schizophrenia patients. This study provides i) comprehensive data on a poorly characterised population, ii) a valuable CYP2D6 genotyping strategy and iii) due to their unique genetic profile, provides the basis for pharmacogenetic intervention for Xhosa individuals. [source] The Garífuna (Black Carib) people of the Atlantic coasts of Honduras: Population dynamics, structure, and phylogenetic relations inferred from genetic data, migration matrices, and isonymyAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 1 2010Edwin-Francisco Herrera-Paz The aim of this study is to assess population dynamics, structure, and phylogenetic relations of the populations that inhabit the Caribbean coasts of Honduras: the Garífuna (or Black Carib) people, an admixture of Black Africans and Red Carib Native Amerindians. Thirteen autosomal tetranucleotide microsatellite markers of the DNA (namely short tandem repeats) were genotyped in samples from the Garifuna communities of Bajamar, in the Department of Cortés; Corozal, in the Department of Atlántida; and Iriona, in the Department of Gracias a Dios. Each subject in the study filled a questionnaire with the following information: complete name and surname of participant, and places of birth of the participant, his/her parents, and grandparents. We performed analyses that included determination of migration rates and residence patterns from information of places of birth, fixation indices from genetic data, and analysis of surnames of the sampled subjects (isonymy). Migration matrices showed a migration wave from east to west in the parents and grandparents of the subjects. A raise in migration rates and a shift in predominating residence pattern from neolocality to matrilocality from grandparents to parents were observed. Analysis of isonymy conjunctly with values for FIS in each community showed high endogamy in Bajamar, and recent, high immigration in Iriona. A dendrogram constructed with allele frequencies of the Garifuna and other populations from the Americas, Africa, and Europe revealed the close relationships of this ethnic group with Afro-Caribbean and African Populations. Am. J. Hum. Biol. 2010. © 2009 Wiley-Liss, Inc. [source] Assessing diabetic control , reliability of methods available in resource poor settingsDIABETIC MEDICINE, Issue 3 2002A. P. Rotchford Abstract Aims and methods To examine the reliability of random venous or capillary blood glucose testing, random urine glucose testing, and a current symptom history in predicting a high HbA1c in Type 2 diabetic patients taking oral hypoglycaemic agents in a poorly controlled rural African population. Results For a cut-off point for HbA1c of , 8%, for random venous plasma glucose of , 14 mmol/L (present in 47.2% of subjects), specificity was 97.1% (95% CI 85.1,99.9), sensitivity 56.8% (48.8,64.5) and positive predictive value (PPV) 98.9% (94.2,99.9). HbA1c, 8% is predicted by a random capillary blood glucose of 17 mmol/L (present in 28.4% of subjects) with specificity 100% (90.0,100.0), PPV 100% (93.7,100.0) and sensitivity of 34.3% (27.2,42.1). HbA1c, 8% is predicted by the presence of heavy glycosuria (, 55 mmol/L) (present in 35.6%) with specificity 94.1% (80.3,99.3), sensitivity of 41.9% (34.1,49.9) and PPV 97.1% (89.9,99.6). Polyuria/nocturia (present in 31.3%) was the only symptom found to be associated with poor control, with a specificity for predicting HbA1c of , 8% of 81.5% (61.9,93.7), PPV 89.1% (76.4,96.4) and sensitivity 30.6% (22.9,39.1). Conclusions Where resources are short, random glucose testing can be used to detect a significant proportion of those with the worst control with a high degree of specificity enabling primary care staff to modify treatment safely. Where facilities are limited capillary blood or urine testing with reagent strips, may be substituted for venous plasma testing in the laboratory. A symptom history was insufficient to replace biochemical testing, but where this is unavailable, urinary symptoms may be helpful. Diabet. Med. 19, 195,200 (2002) [source] The Relationship Between Helicobacter pylori Infection, the Virulence Genotypes of the Infecting Strain and Gastric Cancer in the African SettingHELICOBACTER, Issue 4 2001J. A. Louw Abstract Background. The relationship between Helicobacter pylori infection and gastric carcinoma remains controversial, especially in the African setting where infection is common, while gastric cancer is perceived to be uncommon, the basis of the so called ,African enigma'. This discrepancy between infection and the development of disease is commonly attributed to differences in host, environment and bacterial factors. Interest in the bacterial factors has focused on heterogeneity in the so-called ,virulence genes'. Aim. The aim of this prospective, case-controlled study was to establish whether H. pylori infection is significantly associated with gastric cancer and to investigate whether gastric cancer is associated with genotypically distinct (as it relates to the candidate virulence genes) organisms in this population. Methods. Patients with histologically confirmed gastric cancer were matched with nonulcer dyspeptic controls for age (within 5 years), gender and ethnicity. Helicobacter pylori status was determined by RUT, histology, culture and serology (locally validated and used as default determinant of H. pylori status). Tumors were classified according to the Lauren classification. The ,virulence genotype' of 17 paired culture samples was determined by previously described and validated molecular techniques (cagA presence, vacA alleles, structure of the cag pathogenicity island and analysis of the iceA alleles). Categorical variables were analysed by the ,2 test. Results. Forty-eight patients (median age 59 years) could be adequately matched to controls. 39/48 (81%) cases and 43/48 (90%) controls were H. pylori positive (NS). Significant differences in the virulence genotypes of infecting strains were noted: vacAs2-controls 24%, cases 0%, p < .00001; vacAs1 present , cases 100%, controls 76%, p < .05; cagA -3,-length > 650 bp , cases 47%, controls 0%, p < .002; cag pathogenicity island intact , cases 82%, controls 43%, p < .04; iceA1 , cases 53%, controls 6%, p < .005. cagA was found in all subjects. Conclusion. This study indicates that, in this African population at least, there is no difference in the prevalence of H. pylori infection when comparing gastric cancer cases with matched controls. However, the findings suggest that gastric cancer may be associated with infection by organisms that are genotypically different from those not associated with disease. [source] The widespread use of skin lightening creams in Senegal: a persistent public health problem in West AfricaINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 2 2002Pascal Del Giudice MD Background The use of skin lightening creams is common in the female population of some African countries. The long-term use of certain products for several months to years may cause cutaneous adverse effects. Methods From 1992 to 1993, we conducted an epidemiologic and clinical study in Dakar, Senegal. Women were questioned about the use of skin lightening creams and examined for potential adverse skin reactions. Six hundred and eighty-five Senegalese women participated in the study. Results Twenty-six per cent of women were using skin lightening creams at the time and 36% had used them at some time. The most common products used were hydroquinone and corticosteroids, but 25% of women had used products of unknown composition. Seventy-five per cent of women using such creams showed cutaneous adverse effects. Facial acne was the most common adverse effect. Conclusions A major part of the female adult population of Senegal used skin lightening creams. The long-term use of these creams is responsible for a high rate of cutaneous adverse effects. This practice has also been reported in other countries from sub-Saharan Africa and suggests a widespread use in the African population. [source] No relationship observed between human p53 codon-72 genotype and HPV-associated cervical cancer in a population group with a low arginine-72 allele frequencyINTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 3 2007V. A. Govan Summary Infection with high-risk human papillomavirus (HR-HPV) is a necessary but not a sufficient event in the development of cervical cancer, as most infections regress without intervention. Thus, genetic host factors and cellular immune responses could be potential modifiers for the risk of developing cervical cancer. In particular, p53 is considered as the most critical tumour suppressor gene and is involved in regulating cell division. The polymorphism on p53, which encodes either a proline or an arginine amino acid residue at codon 72, has been reported as a possible risk factor for cervical disease. This polymorphism has been shown to differentially affect the efficiency of degradation of p53 protein mediated by HR-HPV E6 oncoprotein. Women with histologically proven cancer of the cervix (n = 111) and hospital-based controls (n = 143) were included in this study. The patients and controls were from the Western Cape Province in South Africa. Genotyping of the p53 polymorphism was conducted using polymerase chain reaction and restriction fragment-length polymorphism method. The distributions of the allelic frequencies were stratified in both patients and controls into two South African ethnic population groups. In this study, we observed no association between the distribution of p53 polymorphism and susceptibility to cervical cancer in the Western Cape Province populations (P = 0.466). However, the frequency of the Pro/Pro residue at codon 72 was increased in the South African population when compared to Caucasians, Indians and Portuguese population groups. Notably, as the distribution of the Pro/Pro at codon 72 of p53 gene was significantly different (P < 0.05) between the control groups of South Africa and other population groups. This result suggests that ethnic disparity may influence the levels of p53 produced. [source] Hepatitis B viral loads in southern African Blacks with hepatocellular carcinomaJOURNAL OF MEDICAL VIROLOGY, Issue 9 2009Raquel Viana Abstract Although viral loads are known to influence the development of hepatitis B virus-induced hepatocellular carcinoma in a number of populations, little information is available in the Black African population. Black African patients with hepatocellular carcinoma differ from those in other populations in having a lower frequency of e antigen-positivity and in other respects that might affect viral loads. Hepatitis B viral loads were measured using real-time polymerase chain reaction assay in 124 Black Africans with hepatocellular carcinoma and compared with those in 125 Black adult asymptomatic viral carriers. The geometric mean viral load in the cancer patients was 553,618,copies/ml (95% CI 301,953,1,015,033,copies/ml), with 62.1% having loads >1,×,105,copies/ml and 87.1% >1,× 104,copies/ml, whereas that in the carriers was 16,084,copies/ml (95% CI 9,184,28,168,copies/ml), with only 15.2% having values >1,× 105,copies/ml and 49.6% >1,×,104,copies/ml (P,<,0.001 in each instance). Mean viral load was significantly higher in e antigen-positive than e antigen-negative cancer patients (5,905,357 copies/ml [1,362,847,25,588,520] cf 238,173 copies/ml [97,200,685,730]: P,<,0.001) after adjusting for age and sex. No statistically significant difference existed between patients in different age groups, in men and women, or in patients infected with genotype A or D after adjusting for the other variables. Conclusion: Black Africans with hepatocellular carcinoma have high hepatitis B viral loads in spite of the relative infrequency of e antigen-positivity. J. Med. Virol. 81:1525,1530, 2009. © 2009 Wiley-Liss, Inc. [source] Predominant human herpesvirus 6 variant A infant infections in an HIV-1 endemic region of Sub-Saharan AfricaJOURNAL OF MEDICAL VIROLOGY, Issue 5 2009Matthew Bates Abstract Human herpesvirus 6, HHV-6, commonly infects children, causing febrile illness and can cause more severe pathology, especially in an immune compromised setting. There are virulence distinctions between variants HHV-6A and B, with evidence for increased severity and neurotropism for HHV-6A. While HHV-6B is the predominant infant infection in USA, Europe and Japan, HHV-6A appears rare. Here HHV-6 prevalence, loads and variant genotypes, in asymptomatic compared to symptomatic infants were investigated from an African region with endemic HIV-1/AIDS. DNA was extracted from blood or sera from asymptomatic infants at 6 and 18 months age in a population-based micronutrient study, and from symptomatic infants hospitalised for febrile disease. DNA was screened by qualitative and quantitative real-time PCR, then genotyped by sequencing at variable loci, U46 (gN) and U47 (gO). HIV-1 serostatus of infants and mothers were also determined. HHV-6 DNA prevalence rose from 15% to 22% (80/371) by 18 months. At 6 months, infants born to HIV-1 positive mothers had lower HHV-6 prevalence (11%, 6/53), but higher HCMV prevalence (25%, 17/67). HHV-6 positive febrile hospitalized infants had higher HIV-1, 57% (4/7), compared to asymptomatic infants, 3% (2/74). HHV-6A was detected exclusively in 86% (48/56) of asymptomatic HHV-6 positive samples genotyped. Co-infections with both strain variants were linked with higher viral loads and found in 13% (7/56) asymptomatic infants and 43% (3/7) HIV-1 positive febrile infants. Overall, the results show HHV-6A as the predominant variant significantly associated with viremic infant-infections in this African population, distinct from other global cohorts, suggesting emergent infections elsewhere. J. Med. Virol. 81:779,789, 2009. © 2009 Wiley-Liss, Inc. [source] Molecular epidemiology of hepatitis B virus in Dakar, SénégalJOURNAL OF MEDICAL VIROLOGY, Issue 3 2006Muriel Vray Abstract Using DNA chip technology and real-time quantitative PCR, molecular profile of HBV strains infecting blood donors and patients in Dakar, Sénégal was studied. All HBsAg-positive blood donors (n,=,175) and all patients who presented with chronic hepatitis B (n,=,29) between 1st June 2003 and 31st July 2003 were studied. One patient, a blood donor, was coinfected by HCV, and nine patients had anti-HDV antibodies. Few persons in either group were HBeAg-positive. Viral load values were relatively low but correlated with biochemical abnormalities. Patients were infected mainly by genotype E (72%). Patients infected by genotype A (28%) tended to be younger than other patients. There was no significant difference between the blood donors and the patients with hepatitis B as regards virological markers, including viral load, when the HBV genotype was taken into account. The BCP A1762T and G1764A mutations were found in four patients and one patient, respectively; the two mutations were never found in the same patient. The W28* mutation at position 1896 of the core was detected in 19 of the 32 genotyped patients, 18 (83%) of whom had genotype E infection. ALT levels were not influenced by HBV mutations. This study shows a low frequency of clinical signs in HBsAg-positive blood donors, a relatively low level of viral replication, and a high frequency of pre-core mutants in this West African population. These results underline the importance of molecular characterization of HBV infection as specific treatments become available in this region. J. Med. Virol. 78:329,334, 2006. © 2006 Wiley-Liss, Inc. [source] Intellectual Disability in the Context of a South African PopulationJOURNAL OF POLICY AND PRACTICE IN INTELLECTUAL DISABILITIES, Issue 2 2008Jennifer Kromberg Abstract, Childhood disabilities, including intellectual disabilities (ID), are thought to occur in 5,17% of children in developing countries around the world. In order to identify and describe the childhood disabilities occurring in a rural South African population, as well as the context in which they occur, a study was carried out in the Bushbuckridge district in the poor northeast part of the country. Altogether, 6,692 children were screened in their homes in eight villages using the Ten Questions questionnaire. This questionnaire was used by local-trained field-workers in interviews with mothers and other carers, to screen children for five disorders (viz., intellectual, hearing, visual and movement disorders, and epilepsy). Altogether, 722 (10.8% of the total sample) children, who screened positive, were examined at clinics in their villages by a pediatrician for diagnostic, treatment, and referral purposes. In addition, 100 traditional healers in the district were interviewed with a specially designed schedule of questions to assess their attitudes toward disabilities and their management of affected children. The results showed that 291 (4.3%) children had at least one of the five disabilities. ID occurred in 3.6%, epilepsy in 0.7%, visual disorders in 0.5%, movement disorders in 0.5%, and hearing disorders in 0.3%. More boys than girls with hearing disorders were receiving special education. Many of the affected children were not receiving treatment or education, resulting in a reduction in their quality of life. Traditional healers were attempting to treat epilepsy and seldom referred affected children to hospital, although effective treatment was available there. Genetic factors were involved in about half the conditions, but genetic services were negligible. Appropriate health, diagnostic, treatment, educational, and supportive services are required for children with disabilities, and awareness of their needs and the resources to meet them should be increased in this community. [source] New method for age estimation of developmental defects of enamel formation in living populationsAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 4 2010Rhonda Gillett-Netting Histologically based age of occurrence estimates for developmental defects of enamel (DDE) are raising questions about the continued utility of traditional macroscopic methods; however, the new techniques are not appropriate for use on living populations. This study, using methodology suitable for noninvasive use on living populations, compares assignment of defect timing using a histologically informed macroscopic method (HIMM) versus traditional methodology (TM). For this Southern African population, TM estimates later median age of DDE occurrence than HIMM (Z -score: ,13.565, P < 0.000) and modal age is 1 year earlier. HIMM allows for continued collection of DDE in living populations with the added benefit of more precise timing of enamel development. Accuracy for estimating general stressors during childhood is necessary for construction of diachronic analyses. Am. J. Hum. Biol., 2010. © 2010 Wiley-Liss, Inc. [source] Heritabilities of somatotype components in a population from rural MozambiqueAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 6 2008Sílvio Pedro José Saranga There have been few genetic studies of normal variation in body size and composition conducted in Africa. In particular, the genetic determinants of somatotype remain to be established for an African population. (1) To estimate the heritabilities of aspects of somatotype and (2) to compare the quantitative genetic effects in an African population to those that have been assessed in European and American populations. The sample composed of 329 subjects (173 males and 156 females) aged 7,17 years, belonging to 132 families. The sibships in the sample ranged in size from two to seven individuals. All sampled individuals were residents of the Calanga region, an area located to the north of Maputo in Mozambique. Somatotype was assessed using the Heath-Carter technique. Herit abilities were estimated using SAGE software. Moderate heritabilities were determined for each trait. Between 30 and 40% of the variation in each somatotype measure was attributable to genetic factors. The heritability of ectomorphy was 31%. Mesomorphy was similarly moderately heritable, with ,30% of the variationattributable to genetic factors. The heritability of endomorph was higher in the Calanga population (h2 = 0.40). Quantitative genetic analyses of somatotype variation among siblings indicate that genetic factors significantly influence endomorphy, mesomorhpy, and ectomorphy. However, environmental factors also have significant effects on the variation in physique present in the population of Calanga. Lack of proper nutrition, housing, medical assistance, and primary health care, together with very demanding and sex-specific daily chores may contribute to the environmental effects on these traits. Am. J. Hum. Biol., 2008. © 2008 Wiley-Liss, Inc. [source] The history and composition of the Raymond A. Dart Collection of Human Skeletons at the University of the Witwatersrand, Johannesburg, South AfricaAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2009Manisha R. Dayal Abstract The Raymond A. Dart Collection of Human Skeletons (Dart Collection) is housed in the School of Anatomical Sciences at the University of the Witwatersrand, Johannesburg, South Africa, and comprises one of the largest documented cadaver-derived human skeletal assemblages in the world. This collection originated in the early 1920s as a result of the efforts of Raymond Dart and continues to grow. The skeletons included represent varied indigenous and immigrant populations from southern Africa, Europe and Asia. This contribution documents the history of the collection and provides an updated inventory and demographic assessment of this valuable research collection. According to a recent inventory the Dart Collection currently comprises 2,605 skeletons representing individuals from regional SA African (76%), White (15%), Coloured (4%) and Indian (0.3%) populations. A large proportion of the skeletons (71%) represent males. The recorded ages at death range from the first year to over 100 years of age, but the majority of individuals died between the ages of 20 and 70. The Dart Collection has been affected by collection procedures based on availability. All of the cadavers collected before 1958, and large proportions subsequently, were derived from unclaimed bodies in regional South African hospitals. Some details of documentation (age at death, population group) are estimates and some aspects of the collection demographics (sex ratios) do not closely reflect any living South African population. Our inventory and analysis of the Dart Collection is aimed to assist researchers planning research on the materials from this collection. Am J Phys Anthropol, 2009. © 2009 Wiley-Liss, Inc. [source] Anthropometry and Breast Cancer Risk in Nigerian WomenTHE BREAST JOURNAL, Issue 5 2006FWACS, Michael N. Okobia MBBS Abstract: The recent upsurge in global obesity and the recognition of the role of metabolic syndrome and other correlates of obesity in the etiology of breast cancer and other chronic diseases has created the impetus for renewed interest in the role of anthropometric measures in breast cancer risk. This case-control study was designed to evaluate the role of anthropometric variables in breast cancer susceptibility in an indigenous sub-Saharan African population drawn from midwestern and southeastern Nigeria, a population grossly underreported in the global epidemiologic literature. Study participants were 250 women with breast cancer who were receiving treatment in the surgical outpatient clinics and surgical wards of four university teaching hospitals located in midwestern and southeastern Nigeria, while the controls were 250 age-matched women without breast cancer or other malignant diseases being treated for other surgical diseases in the same institutions between September 2002 and April 2004. Waist:hip ratio (WHR) was associated with a significant 2.5-fold increased risk of premenopausal breast cancer (odds ratio [OR] = 2.56, 95% confidence interval [CI] 1.48,4.41] and a 2-fold increased risk of postmenopausal breast cancer (OR = 2.00, 95% CI 1.04,2.53). Increasing height conferred a modestly nonsignificant increased risk of premenopausal breast cancer (OR = 1.59, 95% CI 0.98,2.58). The study showed that WHR is a significant predictor of breast cancer risk in Nigerian women and measures to sustain increased physical activity and ensure healthy dietary practices are recommended to reduce the burden of obesity in the population. [source] Frequency of the basal-like phenotype in African breast cancer,APMIS, Issue 12 2007HAWA NALWOGA Basal-like breast carcinoma has been recognized as a subtype with specific prognostic implications. However, there is a lack of reports about this category of breast tumors in African women. The aim of this study was to explore the basal-like phenotype in breast cancer patients in an African population, and a registry-based series was included from the well-defined Kyadondo County in Uganda (1.7 millions). We studied a total of 65 archival paraffin blocks of invasive breast cancer using antibodies against cytokeratin 5/6 and P-cadherin, and these markers were expressed in 34% of all cases and in 52% of ER (estrogen receptor)-negative tumors. All basal-like tumors were ER negative (p<0.0005) and PR (progesterone receptor) negative (p=0.002). Basal-like breast carcinomas were of a higher histologic grade (p=0.001), had high mitotic counts (p=0.002), and marked nuclear pleomorphism (p=0.002). P-cadherin-positive tumors had a high Ki-67 proliferative rate (p=0.039). In conclusion, the basal-like phenotype is frequent in this African series of breast cancer and is strongly associated with poor prognostic factors. Our findings might be significant in relation to clinical management of these patients, including novel targeted therapy. [source] Association of ankylosing spondylitis with HLA,B*1403 in a West African populationARTHRITIS & RHEUMATISM, Issue 11 2002Carlos López-Larrea Objective To investigate the contribution of HLA class I alleles in the susceptibility to primary ankylosing spondylitis (AS) in West African patients living in Togo. Methods A large epidemiologic analysis of 9,065 West African rheumatology patients living in Togo was performed in order to identify those who had AS. Eight Togolese patients with AS were identified. HLA was typed by polymerase chain reaction using sequence-specific oligonucleotide probes. DNA typing was also performed on a control population of 85 healthy subjects matched for ethnic background. Results A significant association between AS and B*14 was identified. This allele was found in 62.5% of the AS patients (odds ratio 69), but was carried by only 2% of the healthy controls. Analysis for B14 subtypes showed that B*1403 was the predominant allele in AS patients (odds ratio 171), and that this allele was absent in healthy controls. B27 was virtually absent, being observed in only 1 AS patient (B*2705). Conclusion HLA,B*1403 shows the B27 "supertype" motif and may exert an effect on AS susceptibility according to the arthritogenic peptide model. The association of B*1403 with AS has not previously been reported in either population. [source] A test for Allee effects in the self-incompatible wasp-pollinated milkweed Gomphocarpus physocarpusAUSTRAL ECOLOGY, Issue 6 2009GARETH COOMBS Abstract It has been suggested that plants that are good colonizers will generally have either an ability to self-fertilize or a generalist pollination system. This prediction is based on the idea that these reproductive traits should confer resistance to Allee effects in founder populations and was tested using Gomphocarpus physocarpus (Asclepiadoideae: Apocynaceae), a species native to South Africa that is invasive in other parts of the world. We found no significant relationships between the size of G. physocarpus populations and various measures of pollination success (pollen deposition, pollen removal and pollen transfer efficiency) and fruit set. A breeding system experiment showed that plants in a South African population are genetically self-incompatible and thus obligate outcrossers. Outcrossing is further enhanced by mechanical reconfiguration of removed pollinaria before the pollinia can be deposited. Self-pollination is reduced when such reconfiguration exceeds the average duration of pollinator visits to a plant. Observations suggest that a wide variety of wasp species in the genera Belonogaster and Polistes (Vespidae) are the primary pollinators. We conclude that efficient pollination of plants in small founding populations, resulting from their generalist wasp-pollination system, contributes in part to the colonizing success of G. physocarpus. The presence of similar wasps in other parts of the world has evidently facilitated the expansion of the range of this milkweed. [source] A Chilean boy with severe photosensitivity and finger shortening: the first case of homozygous variegate porphyria in South AmericaBRITISH JOURNAL OF DERMATOLOGY, Issue 2 2006P. Poblete-Gutiérrez Summary A 7-year-old Chilean boy presented with severe photosensitivity, blistering, erosions and scarring on sun-exposed areas of the body since the age of 6 months. Additionally, he showed a short stature and shortening of the fingers. Laboratory examination revealed greatly elevated protoporphyrin levels in the blood. Such biochemical findings can be observed in homozygous variants of usually autosomal dominantly inherited acute porphyrias such as variegate porphyria (VP) and hereditary coproporphyria, which usually do not become manifest before the second or third decade of life in heterozygotes. Using polymerase chain reaction-based techniques we identified a missense mutation in exon 7 on the paternal allele and a frameshift mutation in exon 13 on the maternal allele of the protoporphyrinogen oxidase gene that harbours the mutations underlying VP. This is the first homozygous case of VP in South America. As VP represents the most frequent type of acute porphyria not only in Chile but also in South Africa, more such cases could be expected in the future, particularly because a founder mutation for this disease has already been described in the Chilean and South African population. [source] Sleep habits in Nigerian undergraduatesACTA NEUROLOGICA SCANDINAVICA, Issue 1 2010O. S. A. Oluwole Background,,, Quantity of night sleep is shorter than 8 h in several developed countries, but similar data is not available for most African countries. The objective of this study was to describe the quantity of night sleep, factors that are associated with non-restorative sleep, and sleep habits in a population of undergraduates in Nigeria. Methods,,, Questionnaires were used to collect information about bedtimes, waketimes, intra-night awakenings, non-restorative sleep, and afternoon naps over a period of 14 days. Results,,, Mean duration of night sleep was 6.2 h (median 6.0, range 4.5,9.3), while mean duration of daytime naps was 70 min (median 75, range 10,315). Duration of night sleep was associated with day of the week and gender, but not with BMI. Non-restorative sleep, which occurred 25% of total sleep times, was associated with night sleep ,5 h, hypnotic use, alarm to wake, heavy workload, and afternoon naps. Intra-night sleep awakening occurred 58.5% of total sleep times. Afternon naps were taken by 225 (82%) of subjects. Conclusion,,, Duration of night sleep in this African population is not longer than the duration in Western countries. Intra-night awakening and non-restorative sleep; however, occur more frequently, and afternoon nap is usually in excess of 1 h. [source] The frequency of absence of palmaris longus in a South African population of mixed raceCLINICAL ANATOMY, Issue 4 2010Robert Ndou Abstract The palmaris longus (PL) is a weak flexor of the wrist that may be harvested as a tendon graft and used in surgical procedures for reconstructive purposes. The PL is congenitally absent in 15% of the worldwide population. However, the frequency of absence varies considerably among different population groups, being as high as 63.9% in the Turkish population and as low as 3% in the black population in the Republic of Congo. In this study, South African persons of mixed race (n = 201) were assessed by two anatomists for the presence of the PL tendon using three clinical tests, namely the Traditional Test, Mishra's Test II, and the Gangata Test. The most reliable of the three tests used was determined using Kendall's coefficient of concordance. Of the total number of subjects used, 11.5% had absence (either bilaterally or unilaterally) of the PL tendon. There was a 5.5% bilateral absence of the PL. The study revealed that the PL tendon may present in six different patterns according to the clinical assessment tests applied, the presence or absence of the PL alongside the flexor capi radialis, and the degree of prominence of PL, if present. Using the Kendall's coefficient of concordance, the Mishra's Test II, and the Gangata Test, both involving abduction of the thumb, were found to be most effective in revealing the PL. The frequency of absence of the PL in South Africans of mixed race has been determined. Clin. Anat. 23:437,442, 2010. © 2010 Wiley-Liss, Inc. [source] A variant of the myosin light chain kinase gene is associated with severe asthma in African AmericansGENETIC EPIDEMIOLOGY, Issue 4 2007Carlos Flores Abstract Asthma is a complex phenotype influenced by environmental and genetic factors for which severe irreversible structural airway alterations are more frequently observed in African Americans. In addition to a multitude of factors contributing to its pathobiology, increased amounts of myosin light chain kinase (MLCK), the central regulator of cellular contraction, have been found in airway smooth muscle from asthmatics. The gene encoding MLCK (MYLK) is located in 3q21.1, a region noted by a number of genome-wide studies to show linkage with asthma and asthma-related phenotypes. We studied 17 MYLK genetic variants in European and African Americans with asthma and severe asthma and identified a single non-synonymous polymorphism (Pro147Ser) that was almost entirely restricted to African populations and which was associated with severe asthma in African Americans. These results remained highly significant after adjusting for proportions of ancestry estimated using 30 unlinked microsatellites (adjusted odds ratio: 1.76 [95% confidence interval, CI: 1.17,2.65], p = 0.005). Since all common HapMap polymorphisms in ,500,kb contiguous regions have low-to-moderate linkage disequilibrium with Pro147Ser, we speculate that this polymorphism is causally related to the severe asthma phenotype in African Americans. The association of this polymorphism, located in the N-terminal region of the non-muscle MLCK isoform, emphasizes the potential importance of the vascular endothelium, a tissue in which MLCK is centrally involved in multiple aspects of the inflammatory response, in the pathogenesis of severe asthma. This finding also offers a possible genetic explanation for some of the more severe asthma phenotype observed in African American asthmatics. Genet Epidemiol 2007. © 2007 Wiley-Liss, Inc. [source] ,MOVING AROUND': THE SOCIAL AND SPATIAL MOBILITY OF YOUTH IN LUSAKAGEOGRAFISKA ANNALER SERIES B: HUMAN GEOGRAPHY, Issue 3 2008Katherine V. Gough ABSTRACT Claims have recently been made for a ,mobilities paradigm' which is challenging the relative ,a-mobile' focus of much of the social sciences. The agenda drawn up for this mobilities paradigm is clearly based on Northern trends with little consideration of the South. African populations have always been mobile but little is known about the mobility of urban populations and in particular of the youth, who constitute a large proportion of the population. This paper explores the daily and residential mobility of young people in Lusaka building upon interviews held with low- and middle-income youth. The aim is to contribute to discussions of: how mobility varies by gender and class; the links between spatial mobility and social and economic mobility; the nature of the relationship between patterns of mobility and residential structure; and how examining mobility can illuminate many other aspects of young people's lives. Overall the picture emerging from Lusaka is rather bleak. In a context of spiralling economic decline and rising HIV/AIDS rates, the social mobility of youth is predominantly downwards which is reflected in the residential and daily mobility patterns of the young people. There is a strong link between young people's mobility and their livelihoods, an aspect of mobility that is widespread in the South but largely overlooked by the emerging mobilities paradigm. [source] Distribution of killer cell immunoglobulin-like receptor genes in PolesINTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 4-5 2008E. Majorczyk Summary Killer cell immunoglobulin-like receptors (KIRs) present on natural killer cells and minor subpopulations of T cells recognize class I human leucocyte antigen (HLA) molecules on the surface of target cells. Humans differ by the presence or absence of some KIR genes on their chromosomes. As KIRs are important for the outcome of tissue transplantation (particularly for haematopoietic stem cell transplantation) and possibly for pregnancy and autoimmune diseases, knowledge of the KIR gene distribution in a given human population is of practical value. Therefore, we tested 363 healthy individuals from Western Poland for the presence or absence of KIR genes. Results are compared with those published for other human populations. KIR gene frequencies in Poles are close to these in other Caucasoids but different from those in Asian and African populations, and particularly distant from those in Australian Aborigines. [source] Variability in TRBV haplotype frequency and composition in Caucasian, African American, Western African and Chinese populationsINTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 6 2005J. L. Brzezinski Summary The polymorphic T-cell receptor V, (TRBV) genes encode much of the variable region of the T-cell receptor , chain. Analysis of allele frequencies of three closely linked polymorphic TRBV genes, TRBV7-3, TRBV9 and TRBV6-4, was undertaken in several populations. The frequencies of these alleles are not significantly different in populations of Caucasians, African Americans and Western Africans. However, Chinese population is extremely homogenous at all three loci. The current study identifies the existence of haplotypic relationships between alleles of these genes in the Caucasian population. The ORF allele TRBV7-3*A3 is found exclusively on chromosomes bearing TRBV9*A2 and TRBV6-4*A2 in this cohort. In contrast, TRBV7-3*A1 and the null allele TRBV7-3*A2 are associated only with TRBV9*A1 and TRBV6-4*A1. This pattern of linkage disequilibrium (LD) is altered in the African American and Western African populations. In these cohorts, there is a marked reduction in LD between alleles of TRBV7-3 and TRBV9. This study is consistent with previous population genetic studies wherein African-derived samples have a greater level of genetic diversity compared to Caucasians. These data also demonstrate that patterns of LD are not consistent across the entire TRBV locus. [source] Evidence of artificial cranial deformation from the later prehistory of the Acacus Mts. (southwestern Libya, Central Sahara)INTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 4 2008F. Ricci Abstract The 1999,2001 Italian,Libyan Archaeological Mission in the Acacus and Messak, southwestern Libya, resulted in the discovery of human specimens from the Wadi Tanezzuft Valley belonging to the Final Pastoral horizon (i.e. late Neolithic, about 3000 years bp). Some of these show clear traces of artificial cranial deformation. This practice, hitherto unrecorded in the central Sahara, is described and analysed in this paper. It represents an additional source of information about population movements and cultural connections in the area. It does not appear to be gender-related, and neither does it involve all individuals in the sample, suggesting some kind of social and/or cultural differentiation within the group. The pattern of cranial deformation described here is not directly related to types most commonly encountered among recent African populations and elsewhere. It may be considered a combination of antero-posterior and circumferential deformation and thus is referred to as a ,pseudo-circular type'. Archaeological and ethnographic literature related to Africa and southwestern Asia is investigated in order to identify a possible origin of such a custom and its pattern of diffusion. The evidence, according to other sources of information, contributes to interpret this area at the centre of the Sahara as a focal point of population movements and circulation of cultural traditions across North Africa in the latest phases of the Pastoral Neolithic. Copyright © 2008 John Wiley & Sons, Ltd. [source] Cytochrome P450 CYP2C19 genotypes in Nigerian sickle-cell disease patients and normal controlsJOURNAL OF CLINICAL PHARMACY & THERAPEUTICS, Issue 4 2010C. P. Babalola PhD Summary Background and objective:, Subjects with different CYP2C19 genotypes may metabolize proguanil, a pro-drug used for malaria prophylaxis differently and the frequency of the different alleles may be different in patients with sickle-cell disease (SCD) and normal controls. The objective of this study was to evaluate CYP2C19 *1, *2 and *3 allele and genotype frequencies in Nigerian normal controls and SCD patients, and to further compare variant CYP2C19 frequencies in Nigerians with other African populations. Methods:, Genotyping was carried out with PCR and restriction fragment length polymorphism analysis. Results and discussion:, CYP2C19 *1 (84·3 vs. 84·9%) or *2 allele frequency (15·7 vs. 15·1%) was not significantly different between patients with SCD and normal subjects. No *3 allele was detected in the cohort. The SCD group exhibited a statistically significantly lower frequency of *1/*1 genotype (69·6%) compared with normal controls (74·4%). Frequency of *2/*2 was significantly lower in SCD (0·9%) compared with normal controls (4·7%). Frequencies of *1/*2 (29·6 vs. 20·9%) were no different in SCD and normal controls. Conclusion:, Prevalence of CYP2C19 polymorphisms was defined for the first time in Nigerian normal and SCD populations. Nigerian SCD patients exhibited significantly lower CYP2C19 *1/*1 and *2/*2 frequencies than normal controls. No differences were detected in CYP2C19 allele or genotype frequencies in normal subjects between this study and previous reports in other African populations. [source] Extreme long-distance dispersal of the lowland tropical rainforest tree Ceiba pentandra L. (Malvaceae) in Africa and the NeotropicsMOLECULAR ECOLOGY, Issue 14 2007CHRISTOPHER W. DICK Abstract Many tropical tree species occupy continental expanses of rainforest and flank dispersal barriers such as oceans and mountains. The role of long-distance dispersal in establishing the range of such species is poorly understood. In this study, we test vicariance hypotheses for range disjunctions in the rainforest tree Ceiba pentandra, which is naturally widespread across equatorial Africa and the Neotropics. Approximate molecular clocks were applied to nuclear ribosomal [ITS (internal transcribed spacer)] and chloroplast (psbB- psbF) spacer DNA sampled from 12 Neotropical and five West African populations. The ITS (N = 5) and psbB- psbF (N = 2) haplotypes exhibited few nucleotide differences, and ITS and psbB- psbF haplotypes were shared by populations on both continents. The low levels of nucleotide divergence falsify vicariance explanations for transatlantic and cross-Andean range disjunctions. The study shows how extreme long-distance dispersal, via wind or marine currents, creates taxonomic similarities in the plant communities of Africa and the Neotropics. [source] Patterns of population subdivision, gene flow and genetic variability in the African wild dog (Lycaon pictus)MOLECULAR ECOLOGY, Issue 7 2001D. J. Girman Abstract African wild dogs are large, highly mobile carnivores that are known to disperse over considerable distances and are rare throughout much of their geographical range. Consequently, genetic variation within and differentiation between geographically separated populations is predicted to be minimal. We determined the genetic diversity of mitochondrial DNA (mtDNA) control region sequences and microsatellite loci in seven populations of African wild dogs. Analysis of mtDNA nucleotide diversity suggests that, historically, wild dog populations have been small relative to other large carnivores. However, population declines due to recent habitat loss have not caused a dramatic reduction in genetic diversity. We found one historical and eight recent mtDNA genotypes in 280 individuals that defined two highly divergent clades. In contrast to a previous, more limited, mtDNA analysis, sequences from these clades are not geographically restricted to eastern or southern African populations. Rather, we found a large admixture zone spanning populations from Botswana, Zimbabwe and south-eastern Tanzania. Mitochondrial and microsatellite differentiation between populations was significant and unique mtDNA genotypes and alleles characterized the populations. However, gene flow estimates (Nm) based on microsatellite data were generally greater than one migrant per generation. In contrast, gene flow estimates based on the mtDNA control region were lower than expected given differences in the mode of inheritance of mitochondrial and nuclear markers which suggests a male bias in long-distance dispersal. [source] | |||||||||||||||||||||||||||||||