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H T Epstein

Publications and source records attributed to H T Epstein.

10 recordsLinked to original sources
PubMed1991

Lead acetate delays rapid postnatal mouse brain and body growth.

Starting at parturition and continuing until weaning, mothers of five mouse litters received tap water while five others had 10 mg PbAc/ml in their drinking water. The offspring receiving lead from the mothers had significantly lower body weights after the first days of receiving lead; their slowed body growth led to a 2-day delay of onset (usually at 16-18 days) of their last rapid body growth stage. They also had significantly smaller brain weights between age 14 days and weaning (23 days). The onset of rapid brain growth was delayed from its usual onset at 16-18 days to about 22-23 days before rising to about the same value as the control mice at 26 days. Thus, the initial effect on brain growth is decidedly greater than on body growth, though brain weight later reaches close to the control value.

Animals↗
PubMed1991

Strain differences in mouse brain weight gain and spatial-location scores during postnatal development.

Brain weight and performance on a spatial-location test were measured from birth to weaning on mouse strains CD1, Balb/c, and their F1 cross. For CD1, onsets of both the last rapid-brain-growth stage and nonzero scores on the spatial-location test were around age 17 days; asymptotes of both were reached about age 23 days. Balb/c and F1 had at least 5- to 6-day delays of both onsets and asymptotes. For the strains studied, onset of nonzero performance on the spatial-location test may be a provisional indicator of onset of significant and rapid brain growth after age 15 days. The delayed F1 brain growth stage could indicate that control of brain growth about age 20 days resides in an inhibitory factor present in Balb/c but not in CD1.

Animals↗
PubMed1986

Stages in human brain development.

In a 1974 survey of data on human brain and head growth statistically significant peaks in growth rates of human brains were found around ages 11 years and 15 years. In addition, correlations were found in that almost all studies had non-significant peaks around ages 3, 7, 11-12 and 15 years; troughs were found at the intermediate ages (5, 9, and 13 years). More recent data include a very extensive collection of head circumference data from a dozen countries which showed statistically significant peaks around ages 7, 12, and 15 years. Confirmation of those results have been found in data on cortical thickness, photographs of neuronal arbors, and the percent of EEG energy found in the alpha-frequencies (8-13 cps). The proposed peak around age 3 years cannot be decided from existing brain weight and head circumference data bases, but the EEG data and the cortical thickness data supply significant support. Overall, there are statistically significant peaks in brain growth rates at age 7, 11-12, and 15 years, though the latter holds only for males at present. The significance of the stages for development of brain functions is being explored.

Adolescent↗
PubMed1979

Three parameters affecting interlitter variations.

We studied 3 parameters affecting average body weight differences between mouse litters and have arrived at an approximation of the contribution that each makes to such differences. These parameters are birth weight, genetically based growth potential variations, and maternal competence. We have developed methods for controlling these parameters and show that through their application we can reduce litter-average body weight differences from our normal value of more than 24% to about 3%. The vanished 21% consists of 12% due to differences in maternal competence, 6% due to growth potential differences, and 3% due to initial weight differences.

Age Factors↗
PubMed1978

The relationship between brain weight and head circumference from birth to age 18 years.

A relation between head circumference and brain weight of humans is generally believed to exist, but the literature contains only two studies which exhibit a quantitative aspect of the relation, showing that brain weight is proportional to the cube of the head circumference from birth through age 3.5 years. By assembling data from autopsy records, we have been able to show that this cubic relationship holds through brain maturation at around age 18 years.

Adolescent↗
PubMed1978

The effect of litter size on weight gain in mice.

The body weights of rodents at weaning are generally believed to be inversely related to the number of animals in the litter during the birth-to-weaning period. Quantitative data for rats have been published, but not for mice. Using carefully matched litters, we have measured the average body weights of mice raised in litters containing 2, 4, 6, and 12 pups relative to the average body weight of litters of eight pups. Except for the 2 pup litters, the inverse relation was found to hold. It is also shown that the pattern of average weaning weight as a function of litter size is the same as previously published by two other groups using rats.

Aging↗
PubMed1977

Construction of low-variability litters of preweaning mice.

Mouse litter variation at weaning stems from a combination of genetic makeup, intrauterine experience, and postnatal maternal care. The 1st 2 factors may be matched at birth by making up separate litters out of littermate pairs whose birth weights are equal (+/-.02 g). Maternal competence may be matched by exchanging the mothers between the 2 cages each day. These tactics yield litters at weaning whose variability has been very much reduced. The range of litter-average body weights has been reduced from about 40 percent to about 5 percent and the range of litter-average brain weights has been reduced from about 15 percent to about 1-2 percent.

Animals↗
PubMed1977

Rodent brain growth stages: an analytical review.

Study of data in the literature on rat and mouse brain growth from birth to weaning reveals a stagewise growth in average brain weight. Rapid growth occurs in the intervals between days 0-6, 8-12, and 17-23 after birth. Slow growth periods then lie in the intervals 6-8, 12-17, and after 23 days. The first slow growth period is signalled by events occurring at its end: substantial acceleration of synthesis of RNA, DNA, protein, and myelin. The second slow growth period is characterized by at least a 3-day interval during which there is very little increase in average brain weight compared with what occurs just before and just after that period; the correlation among 12 studies is highly significant. Implications are discussed for cross-species' extrapolation of findings about brain development.

Age Factors↗
PubMedDate not supplied

The molecular biology of brain and mind development.

The recent dramatic development of molecular neurobiology has focused almost entirely on biological events in individual brain cells, and it seems that many of the goals of such work will soon be attained. Yet, when we attain those goals, we will still have to ask how this information will enable us to understand the properties of brain cell collectivities and their presumptive roles in higher brain functions. Even general ideas about those functions are not yet well defined. Therefore, it seems worthwhile to start studying correlations of the molecular events to these higher functions to help delineate the molecular aspects that need study. It is readily appreciated that we cannot tell what other animal species see, hear, taste, smell and feel when touching something, though we can foresee the time when we will be able to detail the biochemical and biophysical consequences of all inputs to those senses. Thus, however deep our understanding of the biology of those species, we are unable to establish relations between their biological responses to inputs and their presumptive mental perceptions. Even though humans can use language to talk about those perceptions, we cannot even verify whether someone else's perceptions are the same as our own, as with the old question of whether two individuals see the same thing when viewing something blue. Questions about still higher mental functions of human brains are even less accessible to analysis and can be approached at best, by using correlations. In this article are a number of such questions and their current correlation-level answers.

Aging↗