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Biomedical subjects

W S Pollitzer

Publications and source records attributed to W S Pollitzer.

At least 19 recordsLinked to original sources
PubMed2001

Ancestral proportions and admixture dynamics in geographically defined African Americans living in South Carolina.

We analyzed admixture in samples of six different African-American populations from South Carolina: Gullah-speaking Sea Islanders in coastal South Carolina, residents of four counties in the "Low Country" (Berkeley, Charleston, Colleton, and Dorchester), and persons living in the city of Columbia, located in central South Carolina. We used a battery of highly informative autosomal, mtDNA, and Y-chromosome markers. Two of the autosomal markers (FY and AT3) are linked and lie 22 cM apart on chromosome 1. The results of this study indicate, in accordance with previous historical, cultural, and anthropological evidence, a very low level of European admixture in the Gullah Sea Islanders (m = 3.5 +/- 0.9%). The proportion of European admixture is higher in the Low Country (m ranging between 9. 9 +/- 1.8% and 14.0 +/- 1.9%), and is highest in Columbia (m = 17.7 +/- 3.1%). A sex-biased European gene flow and a small Native American contribution to the African-American gene pool are also evident in these data. We studied the pattern of pairwise allelic associations between the FY locus and the nine other autosomal markers in our samples. In the combined sample from the Low Country (N = 548), a high level of linkage disequilibrium was observed between the linked markers, FY and AT3. Additionally, significant associations were also detected between FY and 4 of the 8 unlinked markers, suggesting the existence of significant genetic structure in this population. A continuous gene flow model of admixture could explain the observed pattern of genetic structure. A test conditioning on the overall admixture of each individual showed association of ancestry between the two linked markers (FY and AT3), but not between any of the unlinked markers, as theory predicts. Thus, even in the presence of genetic structure due to continuous gene flow or some other factor, it is possible to differentiate associations due to linkage from spurious associations due to genetic structure.

Africa↗
PubMed1994

Ethnic and genetic differences in susceptibility to osteoporotic fractures.

A plethora of investigations in recent years has demonstrated the occurrence of ethnic differences in bone mineral content, bone density and fracture rates. These findings indicate that genetic determinants exist both for bone development during growth and for bone loss during aging. Twin and parent-offspring studies have corroborated the existence of a hereditary component. It is most evident in the greater bone mass and lower fracture rate in blacks than in whites. Differences in bone mass between Asians and whites are less clear than between blacks and whites because of disparities in body size and other confounding factors. Black children and adults excrete less urinary calcium than whites on essentially the same diets and consequently retain more calcium in their skeletons. Better calcium retention is commensurate with the faster rate of bone growth of black children.

Adolescent↗
PubMed1994

Hypervariable polymorphism of APO(a) in blacks and whites as reflected by phenotyping.

Genetic polymorphism at the apolipoprotein(a) structural locus was investigated in 203 American blacks using a high-resolution SDS-agarose electrophoresis method followed by immunoblotting, and the gene frequency data were compared with a previously screened American white sample using the same method. Between the two samples, a total of 27 discrete APO(a) allelic isoforms have been documented; of these, 24 were common to both groups. Of the 203 blacks screened, APO(a) immunoreactive isoforms were detected in 201, with a total of 101 distinct phenotypes (67 (33%) single-banded and 134 (67%) double-banded). A similar level of gene diversity was observed at the APO(a) locus in blacks (93%) and whites (94%). Despite having a similar number of alleles and a similar level of gene diversity, the frequencies of some APO(a) alleles were significantly different between blacks and whites. Overall, the frequencies of large-size APO(a) alleles, associated with lower LP(a) levels, were significantly lower (P < 0.0001), while the frequencies of medium-size APO(a) alleles, associated with intermediate LP(a) levels, were significantly higher (P < 0.0001) in blacks than in whites. However, the frequencies of small-size alleles, associated with higher LP(a) levels, were comparable between the two race groups. These data indicate that the observed differences in mean LP(a) levels between whites and blacks may be accounted for by the size variation at the APO(a) structural locus.

Adolescent↗
PubMed1992

Skin color and mortality.

The relation of skin color and mortality from all causes, coronary heart disease, and all cardiovascular diseases was explored in 787 black men and women of the Charleston Heart Study Cohort. Associations were studied by examining rates of mortality during the period 1960-1990 by tertiles of skin color, as measured by reflectometer. Across the tertiles of reflectance there were no significant differences in mortality rates, except for sex differences. Proportional hazard regression analyses were used to investigate the relation between skin color, as a continuous variable, and time to death. Covariates for regression analyses were age, sex, skin color, the interaction of skin color and sex, education, blood pressure, serum total cholesterol, cigarette smoking, body mass index, and history of diabetes. Across the random sample of black men and women there was no significant relation between skin color and time to death, except for lighter skin color and all-cause mortality (p = 0.03). Our study results provided no evidence of a long-term effect of darker skin color, as measured by skin reflectance of light, on mortality from all types of cardiovascular disease, coronary disease, or all causes.

Age Factors↗
PubMed1992

Molecular basis of a unique African variant (A-IV 5) of human apolipoprotein A-IV and its significance in lipid metabolism.

Human apolipoprotein A-IV (apoA-IV) exhibits a genetically determined structural polymorphism amenable to analysis by isoelectric focusing and immunoblotting techniques. We have determined the allele frequency and molecular basis of a unique ApoA-IV*5 allele which is widely distributed among blacks but is absent in other populations. The frequency of the ApoA-IV*5 allele in blacks (N = 308) was estimated to be 3.2%. In comparison to the common ApoA-IV*1 allele, analysis of coding and non-coding sequences of the ApoA-IV*5 allele revealed an in-frame insertion of 12 nucleotides near the carboxyl terminal region of the mature protein. The insertion involves an exact duplication of the second of the four repeats and codes for 4 amino acids glutamic acid (GAA), glutamine (CAG), glutamine (CAG), and glutamine (CAG) and is responsible for the charge shift of the the apoA-IV 5 isoform slightly toward the anode as compared to the wild type apoA-IV 1 isoform on the isoelectric focusing gel. This in-frame insertion occurs in a region which is highly conserved among rat, mouse, and humans. In addition to the 12 nucleotide insertion, the four individuals sequenced for the ApoA-IV*5 allele also revealed a same-sense mutation by replacing G to T at the third position of codon 316. Our preliminary data suggest that this unique black allele marker may be of potentially significance in studies of human lipid metabolism and in microevolution.

Adolescent↗
PubMed1989

Ethnic and genetic differences in bone mass: a review with a hereditary vs environmental perspective.

Based on a review of the literature, ethnic and genetic factors are significant determinants of bone mass, along with such environmental factors as diet and exercise. Differences in bone density between blacks and whites remain even after adjustment for body mass. Black-white differences in bone mass appear to be related to ethnicity because blacks have not only greater skeletal calcium content, but also greater total body potassium and muscle mass. Genetic studies of twins and parent-offspring pairs reflect strong constitutional associations of both bone mineral content and bone density at commonly measured skeletal sites. At least for females, bone mass accumulation by age 20 y is highly associated with maternal bone mass; up to menopause it is enhanced by child-bearing and lactation; beyond menopause environmental factors seem to dominate. Dietary calcium and physical activity are significant in the control of bone mass. These findings are important for osteoporosis and fractures, especially in elderly people.

Aging↗
PubMed1977

The Cajuns of Southern Alabama: morphology and serology.

A survey was conducted of 324 members of the Cajun isolate of Southern Alabama. Tradition and appearance suggest that this population of about 3,000 are not entirely White, Black, or Indian but constitute a triracial community somewhat reproductively isolated and inbred. The earliest American settlement in the area, along the banks of the Mobile and Tombigbee Rivers, lay between Spaniards to the South and Indian tribes on the other sides: Creek, Choctaw, and Cherokee. Physical measurements are reported for 71 adults, plus color of skin, eyes, and hair. X-rays were taken of wrist and ankle bones of some 253 children. Red blood samples were typed on adults and children, and haptoglobin, Gm, and Gc types were determined from serum. History and physical examinations were also made. Physical measurements and observations suggest predominantly White ancestry, and D2 analysis confirms this, with least similarity to Indians. Analysis of serological traits implies almost 70% White, almost 30% Black, and very little Indians genes. Few defects of clear genetic etiology were discovered. Growth patterns judged from X-rays appeared normal. All genetic loci testable were in Hardy-Weinberg equilibrium except Gc. While history and some common surnames suggest endogamy in the past, the medical and serological findings, plus some additional surnames, indicate that the isolate has already been largely diluted or dissolved.

Adolescent↗
PubMed1975

Multivariate analyses of anthropometric and psychometric variables in probands with affective disorders and their families.

Data on 121 subjects, probands with affective disorders, their spouses and first degree relatives, are analyzed by multivariate methods to determine the relationships between physical types and propensity to illness. 56 variables are used: 39 anthropometric measures, age, sex, and 15 psychometric scales. In a canonical analysis between the anthropometric measures and the psychiatric scales, each canonical variable is found to be largely identified with a single psychometric component, as found in a principal components analysis of the psychometric scales. The two major anthropometric components, size and linearity, do not have any clear relationship with the psychometric components. However, a discriminant analysis that takes each individual as being in one of four clinical groups, normal, unipolar depressed, bipolar affective disorder or other, indicates a clear relationship between the anthropometric measures and mental illness; wide face and deep chest are associated with patients who have bipolar affective disorder. Half of the variables studied are sufficient to give virtually the same amount of discrimination as all 56 variables.

Affective Symptoms↗