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Biomedical subjects

Z Stein

Publications and source records attributed to Z Stein.

At least 91 records · Page 5Linked to original sources

Cerebral palsy and newborn care. I: secular trends in cerebral palsy.

Reports of cerebral palsy prevalence rates per live births in recent decades in western nations show a mixed pattern. Declining rates were noted in Bristol, England, and in Denmark; but more recently a rising rate was noted in Ireland. In Western Sweden a decline has been followed by a recent rise, and in Western Australia a rise has been followed by a decline. Rates with not statistically significant changes have been found in Iceland and Birmingham, England, and over the seven-year span of the US Collaborative Perinatal Project, although their over-all direction was downward. No single factor is likely to explain the trends observed.

Australia↗

Cerebral palsy and newborn care. II: Mortality and neurological impairment in low-birthweight infants.

In recent years, neonatal mortality rates for low-birthweight infants have declined both in neonatal intensive care units and in several populations in the industrialized world. With regard to impairment among surviving low-birthweight infants, studies from newborn intensive care units show considerable variation in the reported rates of handicaps. Much of this variation arises from a lack of uniform criteria for diagnosis, sample selection and follow-up, factors further compounded by small sample size. At the present time it is premature to conclude that changes in newborn care have either lowered or raised rates of impairment among surviving low-birthweight infants.

Cerebral Palsy↗

Cerebral palsy and newborn care. III: Estimated prevalence rates of cerebral palsy under differing rates of mortality and impairment of low-birthweight infants.

To maintain a stable over-all prevalence of handicap, the rate of handicap among survivors must decline in parallel to the decline in mortality among live births. The 24 per cent decline in mortality among low-birthweight infants in New York City between 1962 and 1976 requires a 35 to 39 per cent decline in the rate of neurological impairment among low-birthweight survivors simply to avoid the production of an increased number of handicapped children in the population as a whole. Such evidence as we have suggests that the declining morbidity may not be keeping pace with the recent declines in mortality: thus, although more healthy survivors will result from newborn intensive care, a modest increase in the prevalence of handicap may also ensue.

Cerebral Palsy↗

Power considerations in studies of reproductive effects of vinyl chloride and some structural analogs.

We review the evidence examining the relation of reproductive function and exposure to vinyl chloride and selected structural analogs. Investigation of these compounds for possible reproductive effects has focused on paternal exposure, a much less well studied route than maternal exposure. Drawing on animal models, we discuss what is known about the possible reproductive consequences of exposure to the father as well as to the mother. In evaluating the studies of reproductive outcome in relation to vinyl chloride or analogs, we consider what biologic model may have been tested and whether there was statistical power to detect moderate increases in risk. Parameters influencing statistical power are reviewed, and recommended sample sizes are set out which would insure sufficient power, in future studies, to detect adverse effects.

Abnormalities, Drug-Induced↗

Epidemiologic detection of low dose effects on the developing fetus.

Evaluations of the health effects of exposures in the workplace and environment have broadened to include effects on reproduction, as well as on the development of cancer. Models to assess risks associated with varying doses of exposure rest almost entirely on data about cancer. In this paper we discuss some distinctive features of reproduction which bear on the interpretation of such models, when applied to reproduction, rather than carcinogenesis. Dose-response curves describe the relationship between two exposures (smoking and alcohol drinking) and two outcomes (spontaneous abortion and birthweight) are used to illustrate some of the questions which arise in attempting to determine a "safe" level of exposure.

Abortion, Spontaneous↗

Early fetal loss.

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Abortion, Habitual↗

Monosomy X: a chromosomal anomaly associated with young maternal age.

In spontaneous abortions, monosomy X is associated with young maternal age. The finding is not explained by low paternal age or by gravidity. The association may be intrinsic to pregnancies of young women or it may be due to experiences which are commoner in young women.

Abortion, Spontaneous↗

Effect of maternal age on autosomal trisomies.

The effect of maternal age on the genesis of trisomy was studied by comparing data from 362 trisomic and 790 chromosomally normal spontaneous abortions. As a group the trisomies were associated with a substantial increase in maternal age but there were considerable differences in the magnitude of the effect for different trisomies. The effect of increasing maternal age was most pronounced for trisomies involving the small chromosomes, both acrocentric and non-acrocentric. However, trisomy 16 was conspicuously different from trisomies for all the other small chromosomes, both in the reduced importance of increased maternal age and in the high frequency with which it occurred. The effect of increasing maternal age on trisomies for chromosomes in groups A, B and C was less clear than that for the small chromosomes. However, the evidence suggested that trisomy for these chromosomes was associated with a moderate increase in maternal age. It was suggested that the maternal age-dependent trisomies might result from precocious disjunction of the bivalents and random segregation of the resulting univalents, a process which would affect chromosomes with the fewest number of chiasmata and which might be more prevalent if oocytes of older women. It was further suggested that true non-disjunction, that is, the failure of bivalents to separate at anaphase, might also result in the production of trisomies. This process might be independent of, or only slightly influenced by, increasing maternal age but be affected by the presence of large blocks of heterochromatin.

Abortion, Spontaneous↗

A randomized controlled trial of prenatal nutritional supplementation in New York City.

This randomized controlled trial of nutritional supplementation in pregnancy, in a poor black urban population in the United States, aimed to increase the birth weight and influence the postnatal development of the offspring of mothers at high risk of having low birth weight infants. The execution of the research design and adherence to the treatment regimen among the experimental population appeared adequate for a reasonable test of the treatments. At birth, the only significant favorable effect of supplementation observed was the prevention of depressed birth weight among the offspring of mothers who smoked heavily. With balanced protein-calorie supplementation, length of gestation was increased, the proportion of low-birth-weight infants reduced, and mean birth weight raised by 41 gm (not statistically significant). With high protein supplementation, there was an excess of very early premature births and associated neonatal deaths, and there was significant growth retardation up to 37 weeks of gestation. At 1 year of age, significant effects of high protein supplement were found on three psychological measures: visual habituation, visual dishabituation, and mean length of free play episodes. These measures were unrelated to measures of growth at birth and at 1 year of age. There were no detectable residual adverse effects of high protein supplementation at 1 year of age.

Birth Weight↗

Creutzfeldt-Jakob disease: familial clustering among Libyan-born Israelis.

Creutzfeldt-Jakob disease was studied among Libyan-born Israelis, in whom the disease appears with unusual frequency. Interviews with relatives of deceased victims revealed statistically significant clustering within families. The results suggest either a common source of exposure or a genetic influence on susceptibility to the virus.

Adult↗

Child spacing and birth order: effect on intellectual ability in two-child families.

The effect on intellectual ability of the spacing of the birth of siblings was studied in two series of young men from two-child families: (i) 535 pairs of brothers and (ii) 1511 unrelated firstborn and secondborn. Birth-order effect and level of ability were not influenced by length of interval between firstborn and secondborn.

Birth Order↗

Cognitive development and social policy.

The city of Warsaw was razed at the end of World War II and rebuilt under a socialist government whose policy was to allocate dwellings, schools, and health facilities without regard to social class. Of the 14,238 children born in 1963 and living in Warsaw, 96 percent were given the Raven's Progressive Matrices Test and an arithmetic and a vocabulary test in March to June of 1974. Information was collected on the families of the children, and on characteristics of schools and city districts. Parental occupation and education were used to form a family factor, and the district data were collapsed into two factors, one relating to social marginality, and the other to distance from city center. Analysis showed that the initial assumption of even distribution of family, school, and district attributes was reasonable. Mental performance was unrelated either to school or district factors; it was related to parental occupation and education in a strong and regular gradient. It is concluded that an egalitarian social policy executed over a generation failed to override the association of social and family factors with cognitive development that is characteristic of more traditional industrial societies.

Child↗