Biomedical subjects
S A Barnett
Publications and source records attributed to S A Barnett.
Wild mice in the cold: some findings on adaptation.
The house mouse, Mus domesticus, can thrive in natural environments much below its optimum temperature. Thermogenesis is then above that at more usual temperatures. In addition, body weight, and the weights of brown adipose tissue and the kidneys, may be higher than usual. In free populations of house mice cold lowers fertility and may prevent breeding. Other possible limiting factors on breeding are food supply, shelter for nesting and social interactions. In captivity, wild-type house mice exposed to severe cold (around 0 degrees C) at first adapt ontogenetically by shivering and reduced activity. But raised thermogenesis is soon achieved without shivering; nest-building improves; and readiness to explore may be enhanced. Endocrine changes probably include, at least initially, a rise in adrenal cortical activity and in catecholamine secretion. Some females become barren, but many remain fertile. The maturity of fertile females is, however, delayed and intervals between births are lengthened; nestling mortality rises. A limiting factor during lactation may be the capacity of the gut. Similar adaptive changes are observed during winter in some species of small mammals that do not hibernate. But neither the house mouse nor other species present a single, universal pattern of cold-adaptation. Wild-type mice bred for about 10 generations in a warm laboratory environment (20-23 degrees C) change little over generations. In cold they become progressively heavier and fatter at all ages; they mature earlier, and nestling mortality declines. The milk of such 'Eskimo' females is more concentrated than that of controls. If 'Eskimo' mice are returned to a warm environment, they are more fertile, and rear heavier young, than controls that remained in the warm. Despite the heavier young, litter size is not reduced: it may be increased, probably as a result of a higher ovulation rate. Parental effects have been analyzed by cross-fostering and hybridizing. Survival, growth and fertility are all favourably influenced by the intra-uterine and nest environments provided by 'Eskimo' females. 'Eskimo' males are also better fathers. Hence after ten generations the phenotype of cold-adapted house mice shows the combined effects of (a) an ontogenetic response to cold, (b) a superior parental environment and (c) a change genotype. The secular changes in the cold that lead to this phenotype give the appearance of evolution in miniature; but it is equally possible that they represent a genetical versatility that allows rapid, reversible shifts in response to environmental demands.(ABSTRACT TRUNCATED AT 400 WORDS)
Hybrids show parental influence in the adaptation of wild house mice to cold.
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Simultaneous determination of vitamin A acetate, vitamin D2, and vitamin E acetate in multivitamin mineral tablets by high performance liquid chromatography with coupled columns.
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Ethology and man: science or myth?
What is known of human evolution gives us little help in describing the biological nature of man: even our fossil history is obscure, and most statements on the evolution of human behaviour are guesses. The fact that primitive man was a predator on other species does not signify that man is "naturally aggressive" to his own kind. The notion of an inherent drive to aggression has no scientific foundation. Knowledge of the conduct of other species can lead to no valid conclusions about human behaviour. The same limitations apply to interpretations of modern man based on what is known of human hunter-gatherers. Ethology can contribute to human studies (1) by providing methods of observing and analysing behaviour, and (2) by providing hypotheses that can be tested. Zoologically-based hypotheses on the ill effects of crowding have been useful but have proved to be wrong. Others on the effects of stimulation in early life, and on breast-feeding and milk composition, have been more fruitful. Abnormal conduct, such as that of Kanner's syndrome, can be usefully studied by ethological methods. Man is a learner and a teacher, whose knowledge of himself increases slowly with the growth of critical research.
Effects of pregnancy on parental and other activities of laboratory mice.
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Pup-carrying by laboratory mice in an unfamiliar environment.
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Peripheral anosmia and the discrimination of poisoned food by Rattus rattus L.
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The movements of wild and domestic house mice in an artificial environment.
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Editorial: Ethology and development.
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Circadian rhythm of movements of the house rat, Rattus rattus L.
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Methods of analysis for infant formula: Food and Drug Administration and Infant Formula Council Collaborative Study, Phase III.
Phase III of the collaborative study of methods of assay for nutrients in infant formulas was conducted. The study included assay of chloride, phosphorus, proximates (ash, fat, protein, total solids, and carbohydrates), thiamine, total pantothenates, and vitamins A, B12, and E. Most of the methods were those in Official Methods of Analysis, 13th edition, with slight modifications, or methods of the Infant Formula Council. On the basis of the results obtained by the collaborators, the methods for chloride, phosphorus, proximates, thiamine, and vitamin B12 have been adopted official first action. Methods for total pantothenates, vitamin A, and vitamin E were not recommended for adoption at this time because of anticipated improvements in methodology in the foreseeable future.
Methods of analysis for infant formula: Food and Drug Administration and Infant Formula Council Collaborative Study.
Because the U.S. Infant Formula Act of 1980 requires manufacturers to produce formula containing a specific minimum amount of nutrients, it became necessary to establish analytical methods for the nutrients listed in the Act. The Food and Drug Administration, the Infant Formula Council, its member companies, contract laboratories, and other government laboratories undertook a collaborative study of available methods; the specific nutrients studied to date include vitamins A, B6, C, riboflavin, and niacin, and the elements calcium, magnesium, iron, zinc, copper, manganese, sodium, and potassium. The coefficients of variation in most cases have been as good as those that could be predicted from other collaborative studies. The methods studied for these nutrients have been adopted official first action except the method for vitamin A.