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Activity of antioxidant enzymes (superoxide dismutase and catalase) and low molecular weight antioxidants (tocopherol and retinol) was studied in tissues of 8 semiaquatic mammalian species. In animals from different taxa, the enhancement of antioxidant defense can be achieved either by increased enzymatic activity of tissues or elevated concentration of low molecular weight antioxidants. The level of enzymatic and nonenzymatic (low molecular weight) antioxidants, determined in tissues and organs of diving mammals, is likely to be considered as an integral complex, which has evolved to ensure the greatest efficiency of metabolic systems during adaptation to species-specific habitats. [ABSTRACT FROM AUTHOR]

It is established that arterial stiffness is one of the risk factors for cardiovascular morbidity and mortality. We tested the hypothesis that alterations in genetic structure of circadian gene PER3 could affect hemodynamic parameters. Previously, we showed that CLOCK gene variants had a pronounced effect on arterial vasculature. Augmentation index (AIx) was significantly higher in the PER35/5group than in the PER34/4and PER34/5groups, whereas other hemodynamic parameters, such as RWTT, PWV, and ASI, were not significantly different. [ABSTRACT FROM AUTHOR]

We studied the effect of prolonged absence of a photoperiodic signal (constant lighting and constant darkness) on the changes of digestive enzymes' activity in late postnatal ontogenesis of rats. Age-related alterations are characterized as a change in activity of enzymes, as well as a redistribution of the functional activity between the amylo- and lipolytic links, the upper and lower divisions of the gastrointestinal tract. It was shown that along with age, the activity of enzymes is affected both by the absence of photoperiodism and by the level of melatonin associated with the light regime. In conditions of light deprivation the age-related changes characterizing the «aging» of the digestive system are observed later compared with standard illumination and especially constant illumination.

Pineal gland (PG), or epiphysis, is involved in the organization of biological rhythms and adaptive reactions of the organism through the hormone melatonin. It is shown that various factors can influence the morphology and functional activity of the gland. Calcified concretions (corpora arenacea, brain sand) are unique biomineral structures of the PG, the causes of the formation and possible functional significance of which remain unclear until now. Currently, concrements have been found in several species of birds, in many mammals as well as humans; they are absent in fish, amphibians and reptiles. In this review, we have collected the available literature data on the composition, mechanisms of formation, and the possible factors affecting the accumulation of concretions in the epiphysis. Despite the fact that the generally accepted point of view is the age-dependent nature of the accumulation of pineal calcium deposits, the available data on the PG mineralization lead to the conclusion that, most likely, there is a multifactorial mechanism for the formation of concrements. In addition, the nature and crystallinity of the inorganic tissue of the pineal concretions suggest that corpora arenacea is rather a regulated and physiological than pathological type of petrification. The existence of contradictory data on the connection between the formation of brain sand and the change in the functional activity of the PG during seasonal endocrine changes and in the process of aging makes the study of deposits as the necessary and requiring in-depth investigation.