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Biomedical subjects

T Jenkins

Publications and source records attributed to T Jenkins.

At least 145 records · Page 8Linked to original sources
PubMed1989

Prevalence of familial hypercholesterolemia in Johannesburg Jews.

The prevalence of heterozygous familial hypercholesterolemia was determined in a representative sample of 403 young Jewish men resident in Johannesburg, South Africa. Preliminary screening by measurement of serum total cholesterol demonstrated that 25 of them had levels greater than or equal to 7.5 mmol/l (290 mg/dl). On the basis of subsequent clinical, biochemical, and family studies, 6 men, or about 1 in 67 of the total sample, were considered to be heterozygotes. This very high prevalence, about 7 times greater than that found in other Caucasian populations, is probably related to founder effect. It may help to explain the high frequency of coronary heart disease in Johannesburg Jews.

Adult↗
PubMed1989

Strongyloides ratti: studies of cutaneous reactions elicited in naive and sensitized rats and of changes in surface antigenicity of skin-penetrating larvae.

This study provides the first quantitative assessment of the cutaneous reaction elicited in naive and sensitized rats by invading larvae of Strongyloides ratti. Parasites were identified in skin samples harvested from both naive and sensitized rats between 0.5 and 8 h following percutaneous infection, but were no longer visible at the site of invasion at 24 h. Mast cells, neutrophils, eosinophils and mononuclear cells recruited into the dermis in response to invading larvae were recorded and quantified. Cellular infiltrates were observed as early as 1 h post-invasion in naive/challenged skin, where total cell numbers were up to 3 times greater than in naive control tissue. Peak numbers of all cell types were recorded from 3 to 8 h in both naive/challenged and sensitized/challenged hosts. Interestingly, the reaction in sensitized/challenged rats was neither enhanced nor accelerated, a feature perhaps attributable to lack of recognition of parasite antigens by the host. This possibility was investigated by immunofluorescent labelling, which clearly demonstrated changes in the surface antigen profile of the parasite following penetration of the host skin both in vitro and in vivo. It is proposed that these changes in surface antigenicity constitute an evasive stratagem used by the parasite to deter the host from mounting a potentially lethal inflammatory response.

Animals↗
PubMed1989

Albinism and skin cancer in Southern Africa.

The presence of skin cancer was investigated in 111 albinos belonging to the black (Negro) population of Johannesburg, South Africa. The overall rate was 23.4%, the risk increasing with age. Identifiable risk factors included: environmental exposure to ultraviolet radiation; inability to produce ephelides ('freckles'); and possibly ethnicity. The head was the site most commonly affected, and squamous was far more common than basal cell carcinoma. No melanomas were detected. Recommendations are made regarding prevention of skin cancer in the at-risk group.

Age Factors↗
PubMed1988

Phenotypic expression of the HLA-linked iron-loading gene in the Afrikaner population of the western Cape.

A previous study conducted on a group of Afrikaans-speaking subjects in the south-western Cape indicated a high frequency (0.115) of the HLA-linked iron-loading gene which causes idiopathic haemochromatosis. The results of phenotypic and genotypic studies on the first degree relatives of identified homozygotes and heterozygotes are now reported. There was considerable heterogeneity of phenotypic expression in the group of heterozygotes, with overlap between the homozygous and heterozygous subjects. The heterozygous relatives of heterozygous index cases, who had been identified on the basis of a serum ferritin concentration greater than 400 micrograms/l, appeared to have more frequent and more marked abnormalities of iron measurements than the heterozygote relatives of homozygous index cases (serum ferritin value greater than 400 micrograms/l, percentage transferrin saturation greater than 60). This suggests that the screening test was identifying a group of more significantly affected heterozygotes, with biochemical abnormalities that overlapped with the identified homozygotes. The index cases were followed up over a period of 5 years and during this time the 7 subjects diagnosed as heterozygotes showed a progressive increase in serum ferritin concentrations, which suggests some iron accumulation. Individual pedigrees included instances of gene recombination within the major histocompatibility complex, and of probable false-positive genotype assignment. The overall results confirm a high frequency of the gene in this particular community.

Adult↗
PubMed1988

A new high activity plasma cholinesterase variant.

A South African Afrikaans speaking family is reported in which a new high activity plasma cholinesterase variant was found to occur in the mother and son. The variant has the same electrophoretic mobility as the "usual' enzyme, but greater heat stability. Its higher specific activity is associated with a normal number of enzyme molecules. The variant may be inherited as a dominant trait, though its locus is uncertain.

Cholinesterases↗
PubMed1988

Alpha-globin gene cluster haplotypes in the Kalahari San and southern African Bantu-speaking blacks.

Alpha-globin gene cluster haplotypes were determined in Southern African San and negroid populations. Significant differences (P less than .01) between the two groups were found at three of the nine loci in the cluster. The most striking difference, however, was the relatively low level of variation found in the San (alpha alpha)-associated haplotypes and the high level in the SA blacks. This trend was also observed for the 3' hyper-variable region. Nineteen different haplotypes were identified among the 36 haplotypes studied in the black population, but only seven different ones were found among the 37 haplotypes in the San; five were common to both populations. The common San haplotype, (+--MPZ+---), had a frequency of .57 in the San and .11 in the black population; the common SA black haplotype, (---MZ----), occurred at a frequency of .17 but was absent in the San. In the SA black population significant linkage disequilibrium is present between five of the RFLP loci, including the extreme 5' and 3' markers, confirming the absence of a recombination hot spot in the alpha-globin gene cluster.

Africa, Southern↗
PubMed1988

XX true hermaphroditism in southern African blacks: an enigma of primary sexual differentiation.

A high incidence of 46,XX true hermaphroditism exists among southern African blacks. The gonadal distribution and clinical presentation of 38 patients are described. The aim of our study on 11 families with histologically proven XX true hermaphroditism was to determine whether a common genetic or environmental etiology could be identified. Pedigree analysis excluded the presence of a simple inheritance pattern, and no constant environmental factors could be implicated. Hybridization studies with Y chromosome--specific probes (pDP132, pDP61, pDP105, pDP31, pDP97, and pY431-HinfA) excluded the presence of a large portion of Yp in these patients. It is possible that smaller portions of the Y chromosome or one or more X-linked or autosomal mutations, either interacting and/or with incomplete penetrance, are present.

Black People↗
PubMed1987

Idiopathic haemochromatosis. Family studies and results of a pilot prevalence survey.

HLA typing for the A and B loci was carried out in conjunction with measurements of iron status on 38 of the first-degree relatives of 8 patients suffering from idiopathic haemochromatosis (IHC). Seven of the 8 probands had the A3 allele, 2 in the homozygous form. Seven had the B7 allele and in 5 it was present with the A3 allele on the same chromosome. Six family members were diagnosed as homozygous for the HLA-linked iron-loading gene on the basis of genotype assessment, while 27 were assessed as being heterozygous. Five of the 6 homozygous subjects had developed significant iron overload. In contrast, disturbances of iron metabolism in the heterozygotes were mild and present in only 33%. Pseudodominant inheritance of IHC was noted in one family, presumably as the result of a homozygous/heterozygous mating. A pilot epidemiological survey was carried out on 222 Afrikaans-speaking men in an attempt to find affected individuals using the serum ferritin concentration as the screening test. One homozygous subject was identified (genotype A3, B7/A3, B7) and further family studies confirmed the presence of the HLA-linked iron-loading gene. These preliminary results suggest a disease frequency of about 4-5/1,000 in the Afrikaner population.

Adolescent↗
PubMed1987

Pseudocholinesterase variation in southern African populations.

Genetic variation at both the E1 and E2 loci of pseudocholinesterase was studied in 7 southern African populations. In the Ashkenazim and Afrikaners, E1 locus variation was observed and the frequency of the E1a or 'atypical' allele was found to be 0.017 in the Ashkenazim and 0.016 in the Afrikaans-speaking population, similar to those observed in other caucasoid populations. The E1s, or 'silent' allele, was found to occur in the Afrikaans-speaking population at a frequency 2-3 times greater than in other Caucasians, giving an increased risk of scoline-sensitivity. The rarity of the E1a in the Negro and Khoisan populations was confirmed. All 7 populations showed variation at the E2 locus with high frequencies of the E2+ allele in the Caucasians and San, while Negroes showed relatively low frequencies. Coloureds showed intermediate frequencies, consistent with their historical origins.

Alleles↗
PubMed1987

Non-insulin-dependent diabetes mellitus and the 5' hypervariable region of the insulin gene in two South African Indian families.

The hypervariable region 5' to the human insulin gene has been characterised in two South African Indian families, each having two generations of individuals affected with non-insulin-dependent diabetes mellitus (NIDDM). Southern blot analysis, with the restriction endonuclease Pvu II and plasmid phins 310 as a probe, was used. In family 1, class 1 alleles (0.87, 0.79, 0.72 and 0.68 kilobase (kb)) were found at this locus but no linkage with NIDDM was shown. In family 2 a class 3 (2.51 kb) and two class 1 alleles (0.89, 0.76) were found. The 0.89 kb allele appears to be segregating with NIDDM in this family.

Adult↗
PubMed1987

The response of black mothers to the birth of an albino infant.

The nature of the response of 37 black mothers to their albino infants, in comparison with matched controls, was investigated longitudinally by means of interviews and observations. Mothers were found initially to be depressed and unhappy, uncomfortable with close contact with their infants, and reluctant to hold and breast-feed them. When observed in interaction with the infants, the mothers showed fewer behaviors in comparison with the controls. Three months later the mothers appeared to be interacting normally with their infants, but they expressed feelings of unhappiness that persisted until the infants reached 9 months of age. The birth of an albino infant seems to cause a delay in maternal attachment and a sadness similar to that described in connection with the birth of an infant with other congenital disorders.

Black or African American↗