[Cardiac rhythm in healthy newborn infants and in infants from the risk group in the early neonatal period]. / Ritm serdtsa zdorovykh novorozhdennykh i detei gruppy riska v rannem neonatal'nom periode.

Studies of heart rhythm parameters, carried out in 88 healthy newborns and in 117 risk-group babies over the course of the early neonatal period (starting from the second minute and up to the seventh day of life) helped derive the normal values of heart rhythm and determine the time characteristics of regulation mechanism establishment in the early postnatal ontogenesis: from sympathetic tonus and centralization of heart rhythm control in the first hours of life to augmenting parasympathetic tonus and autoregulation. Prenatal risk factors were found conducive to deceleration of the newborn's adaptive reactions even when no clinical symptoms of neonatal abnormalities are detectable. The feeding (sucking) process in health is associated with elevation of cholinergic activity of the autonomic nervous system; this phenomenon underlies the method for assessment of the newborn's adaptation (feeding test). The metabolic parameters are less informative in assessment of postnatal adaptation efficacy as against heart rhythm parameters.

[Differences in the mechanisms of thermoregulation in rats in separate and combined adaptation to cold and heat]. / Razlichiia mekhanizmov termoreguliatsii krys pri razdel'noi i kombinirovannoi adaptatsii k kholodu i teplu.

Combined adaptation of rats to heat and cold increasing mechanisms of thermogenesis enhances resistance to both factors and heat dissipation. Adaptive changes in thermogenesis are mainly a result of activation of adrenergic mechanisms, while the separate cold adaptation is accompanied by hyperfunction of thyroid glands. Mechanisms of heat dissipation in rats of the "combined" group increase even more than those of "heat" group.