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Biomedical subjects

N Goldman

Publications and source records attributed to N Goldman.

At least 73 records · Page 4Linked to original sources
PubMed1990

An assessment of survey data on birthweight.

The objective of this analysis is to determine whether useful information on birthweight can be obtained from a retrospective survey. The 1986 Peru Demographic Health Survey collected both numerical weights (in grams) and subjective assessments of relative size at birth, for infants born during 1981-86. Simple tabulations suggest that reports of both measures are of reasonably high quality. However, a more detailed analysis demonstrates that exclusion of the large proportion (almost one-third) of missing responses on numerical weights can lead to biases in the resulting estimates of the incidence and correlates of low birthweight, of the level of infant mortality, and probably of the relative risk of mortality for low birthweight infants. The results emphasize the necessity of collecting data on the relative size of infants, in addition to information on numerical weights, in populations in which a substantial fraction of infants are born outside the formal health system. The subjective assessments allow the analyst to examine the extent to which infants with missing numerical weights are select and to assess the degree of bias in estimates which are based on the subsample of births with reported weights.

Bias↗
PubMed1990

Mortality differentials by marital status: an international comparison.

Although the greater longevity of married people as compared with unmarried persons has been demonstrated repeatedly, there have been very few studies of a comparative nature. We use log-linear rate models to analyze marital-status-specific death rates for a large number of developed countries. The results indicate that divorced persons, especially divorced men, have the highest death rates among the unmarried groups of the respective genders; the excess mortality of unmarried persons relative to the married has been generally increasing over the past two to three decades; and divorced and widowed persons in their twenties and thirties have particularly high risks of dying, relative to married persons of the same age. In addition, the analysis suggests that a selection process is operating with regard to single and divorced persons: the smaller the proportion of persons who never marry or who are divorced, the higher the resulting death rates.

Adult↗
PubMed1988

The effect of variability in the fertility schedule on numbers of kin.

"The kinship formulas developed by Goodman, Keyfitz, and Pullum (1974) are extended to encompass populations in which fertility varies among women. An expression is derived to determine the amount by which the number of sisters in a heterogeneous population exceeds that in a population with homogeneous fertility. This expression, which is a function of the variance in the gross reproduction rate of the population, can readily be applied to numbers of other kin, such as aunts and cousins. Several trial calculations indicate that calculations of average numbers of sisters based on an assumption of uniform fertility could result in a underestimate of about 13 percent." (SUMMARY IN FRE)

Demography↗
PubMed1987

Proteolysis of human C-reactive protein produces peptides with potent immunomodulating activity.

We have studied the ability of human C-reactive protein to modulate the immune response in vitro. Whereas native C-reactive protein did not induce phagocytic leukocytes to chemotax or to produce superoxide, treatment of purified C-reactive protein with human neutrophil-derived acid proteases produced substances with potent effects on leukocyte function. Close examination of the primary structure of human C-reactive protein revealed three regions evenly distributed throughout the protein each of which contain peptide sequences closely resembling the amino acid sequence of the immunomodulator peptide tuftsin, Thr-Lys-Pro-Arg. We have synthesized the three peptides which include Thr-Lys-Pro-Leu ([Leu4]tuftsin), Gly-Lys-Pro-Arg ([Gly1]tuftsin), and Thr-Lys-Pro-Gln ([Gln4]tuftsin) and assayed them for biological activity. The three synthetic peptides were found to stimulate phagocytic leukocytes to chemotax, produce superoxide, and induce mononuclear cells to produce interleukin 1 in vitro at concentrations similar to those concentrations required for tuftsin to induce these phenomena. These results support a potentially important role for C-reactive protein as a possible immunomodulator during inflammation.

Amino Acid Sequence↗
PubMed1987

Correlations between the human sperm-hamster egg penetration assay and in vitro fertilization results.

The human sperm-hamster egg penetration assay (SPA) has been used to evaluate male fertility under in vivo conditions. The test is not only unstandardized, but agreement does not exist as to the lower limits of normal penetration rates. Therefore, it is not surprising that there is considerable doubt as to whether any correlation exists between SPA results and the behavior of sperm in an in vitro laboratory situation. We investigated this question by examining the SPA results and the subsequent fertilization and cleavage rates in the in vitro fertilization program at Pennsylvania Hospital. The sperm from men whose SPA results were 11% or more fertilized 86% of the morphologically normal and mature human oocytes to which they were exposed. Men whose SPA scores ranged from 1% through 10% fertilized 65% of human oocytes, and men whose sperm failed to penetrate hamster eggs still were able to fertilize 41% of the human oocytes. The differences between these groups are statistically significant. This information can be of practical prognostic value during in vitro fertilization cycles in which the number of mature oocytes seen ultrasonographically appears to be at a minimum.

Animals↗
PubMed1984

Changes in widowhood and divorce and expected durations of marriage.

A new interpretation of mathematical formulas developed by Keyfitz illustrates how the concept of entropy (H) can be applied to the analysis of marriage dissolution. The quantities H(divorce) and H(widowhood) indicate the changes in marriage duration which would result from small, constant changes in duration-specific divorce and widowhood rates, respectively. An examination of values for the United States, Nepal and Colombia illustrates the utility of H(i) in assessing the impact of changes in widowhood and divorce and clarifies the relationship between H and changes in life expectancy.

Colombia↗
PubMed1984

Calculation of life tables from survey data: a technical note.

Life table calculations from survey data are frequently based on events for which exact dates are not available. When these dates are coded in monthly form (e.g., century months), estimates should take into account the fact that the first duration interval--the interval which captures events occurring in the first month of exposure--is half the length of all remaining intervals. Although failure to do so has a trivial effect on many demographic calculations, estimates which are based on events which occur with high frequency in the first few months of exposure can be substantially biased. Estimates of fecundability for four countries in the World Fertility Survey are used to illustrate this bias.

Actuarial Analysis↗
PubMed1983

Sex differences in life cycle measures of widowhood.

Using formulas which measure life cycle characteristics of widowhood as a function of life table survivorship and age at marriage, we illustrate changes in patterns of widowhood and widowerhood since 1950, as well as differences by race, by age of bride and of groom, and by age differences between spouses. Although the current inequality in the risks of widowhood and widowerhood for the average couple is mostly due to sex differences in mortality, a one year age difference between spouses has about the same impact as does a one year difference in life expectancy. Calculations based on current distributions of age of groom by age of bride indicate that the older the age of groom, the greater the age difference between spouses and the higher the likelihood of a woman outliving her husband: the typical groom who marries in his fifties faces a 4 to 1 chance that he will be outlived by his spouse.

Adult↗
PubMed1981

Modification of SV40 T antigen by poly ADP-ribosylation.

The SV40 large T antigen is a multifunctional protein presumed to represent a single translation product of the early viral genes. A wide range of biological controls including the regulation of viral DNA replication, transcription and cell transformation has been attributed to T antigen. Previous evidence has indicated that large T antigen is modified in at least two ways, N-terminal acetylation and amino acid phosphorylation. In this study, we demonstrate a novel modification of a population of SV40 T antigen molecules by poly ADP-ribosylation. The covalent linkage of this oligonucleotide side chain to large T antigen, but not small t antigen, was demonstrated in experiments in which SV40-infected cells were labeled in vivo with 32P-orthophosphate or 14C-adenosine. Treatment of this labeled T antigen with snake venom phosphodiesterase released iso-ADP-ribose or treatment with ADP-ribose glycohydrolase released ADP-ribose. A method has been developed for the in vitro ADP-ribosylation of T antigen present in an infected cell nuclear extract with radiolabeled NAD. Since this type of modification is known to affect enzyme activity, its presence on T antigen suggests a similar role in the regulation of certain biological functions under the control of this protein.

Animals↗
PubMed1981

Dissolution of first unions in Colombia, Panama, and Peru.

An analysis of marital histories from World Fertility Survey data in Colombia, Panama, and Peru indicates a high level of union dissolution: the probabilities of a first union ending by separation within twenty years of the onset of union equal .27, .40, and .18 in the three countries respectively. Dissolution probabilities are especially high among women with young ages at first union and among women residing in urban areas. For all subgroups studied, consensual unions are characterized by several times the risk of separation of legal marriages. Consensual unions are especially frequent among women in rural areas, women with little education and women who enter unions at young ages. The different prevalence of consensual unions among the different subgroups affects the associations between union stability and various correlates so that it becomes essential to investigate the factors affecting union stability for both consensual unions and legal marriages. In spite of high dissolution rates, remarriage rates in all three countries are also high, as are the percentages of time spent in a union. Hence, the potential effects of voluntary disruption of unions on fertility appear to be modest.

Adolescent↗