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Biomedical subjects

E M Winkler

Publications and source records attributed to E M Winkler.

14 recordsLinked to original sources
PubMed1996

Differential fertility and body build in !Kung San and Kavango females from northern Namibia.

The study examines the impact of body build on differential fertility patterns in 93 !Kung San and 85 Kavango females from northern Namibia. In both groups shorter females had more offspring, but also more dead offspring, than taller females. The interaction between body weight and fertility was different in both groups and may be due to different nursing behaviour. There was a positive relationship between the typical pedomorphy and fertility in the !Kung San, and directional selection processes may be important.

Adolescent↗
PubMed1996

Nutritional status as indicator for reproductive success in !Kung San and Kavango females from Namibia.

The interaction between nutritional status, estimated by using Body mass index, and fertility outcome was tested in two female samples from Northern Namibia. It turned out, that !Kung San undernourished females had significantly more total and surviving offspring than well-nourished and overweight females of these population. In contrast within the Kavango group well-nourished females had the highest reproductive success. These group specific differences can be interpreted as special reproductive strategies to maximize the reproductive success under different ecological conditions.

Adolescent↗
PubMed1995

Differential reproductive success and body dimensions in Kavango males from urban and rural areas in northern Namibia.

We investigated differential sex-biased parental investment in relation to social status in 59 Kavango males from Rundu, the administrative and commercial center of the Kavango district in northern Namibia, and in 78 Kavango males from the rural areas around Rundu. Twenty-three body dimensions were used as indicators for the probands' social rank in the groups. The males from Rundu surpassed the males from rural areas in nearly all anthropometric features, but the urban males had significantly less offspring, especially fewer dead offspring. The association between the anthropometric variables and the number and sex of the offspring showed marked differences between the two proband groups. Although in the rural areas robust males had more children than smaller and leaner males, the taller and more robust males from Rundu had fewer offspring than smaller and more slender males. These results indicate that males from rural areas and males from urban areas follow different reproductive strategies.

Adolescent↗
PubMed1993

Sex hormone levels and body hair growth in !Kung San and Kavango men from Namibia.

The relation between hair growth and levels of sex hormones in serum and saliva was investigated in 256 !Kung San and Kavango men (ages 18 to 39 years) from Namibia/Southern Africa. Serum concentrations of total testosterone (Tser), 5 alpha-dihydrotestosterone (DHT), and estradiol (E2) as well as the level of bioavailable non-SHBG-bound testosterone in the saliva (Tsal) were determined by radioimmunoassay. The distribution and density of scalp and facial hair as well as the development of terminal hair on the chest, abdomen, pubic area, arms, fingers, and legs were categorized using objective criteria. Covariance analyses revealed marked differences in the distribution of body hair in the San and the Negro sample. This is partly explained by a significant influence of androgen and estrogen levels on the growth of terminal hair. DHT and the ratio DHT/Tser are significantly positively related to midphalangeal hair growth and negatively to pubic hair development. Tsal, the bioavailable fraction of total testosterone, exerts a weak positive influence on the degree of arm and leg hair growth; the most significant positive effect on the growth of abdominal, arm, and leg hair in our samples is caused by E2. The ratio Tser/E2 correlates significantly negatively with the arm and leg hair development and the ratio DHT/E2 with the degree of abdominal, pubic, arm, and leg hair, whereas lower DHT concentrations occur in men with stronger hair development.

Adult↗
PubMed1993

Metric characters of the hard palate and their cephalometric correlations in Namibian !Kung San and Kenyan tribes.

The metric characters of the head and hard palate of 138 black males from Kenya and 110 male !Kung San from Namibia have for the first time been compared to describe the black and Khoisan variation with respect to these special trait systems. The palate measurements were taken from prints of self-hardening plastic. Nearly all metric characters show significant differences between the two populations, which are reflected in a relevant discriminant function. The analyses of correlations between the individual head and palate measurements yield different correlation patterns in the two samples also with regard to their significance and direction. These results and the generally low correlation coefficients can be explained by the complex processes of allometric head growth, resulting in the Sans' pedomorphous and the blacks' more adultiform head and palate trait combinations.

Adult↗
PubMed1990

[Sex hormone level and body shape of the !Kung San. A contribution to explaining pedomorphic stature of San populations].

In order to test the hypothesis that oestrogens as well as androgens modify the body shape resp. the paedomorphous habitus of !Kung San circulating levels of sex hormones (testosterone, 5 alpha-dihydrotestosterone, and oestradiol in the serum as well as free testosterone in the saliva) of 114 healthy !Kung San men from the Northern Kalahari of Namibia were quantitatively determined by means of the radioimmunoassay method. The probands were described by 50 body measurements and morphological characters like gynaecomastia. The results show that sex hormone concentrations and body shape are significantly correlated in !Kung San men as it has been previously demonstrated for non-African samples. This does not only refer to the expression of sexual dimorphism but also to the special aspect of paedomorphism. The hypothesis of Marrett, Davies and Tobias, however, that the paedomorphous type of the San is due to "over-oestrogenization" could not be confirmed. Rather, the comparatively low testosterone level of the !Kung San men seems to be of significance.

Adult↗
PubMed1980

[Incidence of color blindess in East African Negroes].

1008 Bantu and 295 Nilotes of Kenya were tested with regard to protanopia-deuteranopia by means of the ISHIHARA-Plate No. 11 (16 plates edition). Four (0.55%) of the male Bantu and two (1.03%) of the male Nilotes showed a partial or total red-green-blindness. With the females of these samples no case of defective colour vision was observed.

Black People↗
PubMed1975

Fluorometry of citrate in serum, with use of citrate (pro-3S)-lyase.

We describe a procedure for enzymatic assay of citrate in human serum. The citrate is degraded to acetate and oxaloacetate with citrate oxaloacetate-lyase (pro-3S-CH2-COO- yields acetate) (EC 4.1.3.6). Some oxaloacetate loses CO2 to form pyruvate. Addition of malate and lactate dehydrogenases (EC 1.1.1.37 and 1.1.1.27) permits determination of the oxaloacetate and pyruvate generated, and thus of the citrate concentration. The decrease in NADH concentration is measured fluorometrically. Results obtained for 30 consecutive human sera by this procedure were compared to the procedure in which the citrate is converted to pentabromoacetone. There was no statistically significant difference in values obtained by the two procedures. The range of values (mean plus or minus 2 SD) found for sera from 25 blood donors by this procedure was 12.8-27.2 mg/liter (mean, 19.0 mg/liter). Serum citrate as measured by both procedures during a glucose tolerance test was decreased from initial values under the influence of administered glucose (and endogenous insulin). Insulin concentrations were also measured during these glucose-tolerance tests. Citrate concentrations remain subnormal after the glucose and insulin concentrations return to their initial values. This accords with published reports.

Acetone↗
PubMedDate not supplied

Anthropometric-hormonal correlation patterns in San and Kavango males from Namibia.

Correlations between sex hormone levels and body dimensions--so far investigated only in Caucasian populations--were analysed using data from 114 !Kung San hunter-gatherers and 137 urban and rural Kavango men from Namibia. The androgens testosterone (Tser) and 5 alpha-dihydrotestosterone (DHT) in the serum and free testosterone in the saliva (Tsal) as well as oestradiol (E2) in the serum were determined by the radioimmunoassay method. The body dimensions were described by 50 anthropometric features which were additionally subjected to factor analysis yielding seven factors. Most of the individual measurements as well as the resulting factor scores correlated significantly with the sex hormone variables and the hormone ratios Tser/DHT, Tsal/Tser, and Tser/E2 in the !Kung San and the two Kavango samples. For an extended comparison pertinent data from a German sample were included in the analysis. This made it possible to test the stability of metric hormonal correlations in different populations living under various ecological and economical conditions. While the breadth measurements in all samples show relatively consistent correlations to both absolute hormones and hormone ratios, the correlations to the other body measurements and individual factor scores turn out to be less stable. Here, the effect of sex hormones on physical growth, which is experimentally well documented, is obviously differentially covered by genetic and environmental factors specific for the groups in question.

Adolescent↗