Biomedical subjects
Publications and source records attributed to L V Stepanova.
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The total water content (after antipyrine and tritium oxide), that of extracellular water (after sodium thiosulphate) and of overall metabolic potassium (with reference to K42) were studied concurrently in 34 patients with chronic circulatory insufficiency. Twenty normal subjects served as controls. In the sick the disturbances of the water metabolism made themselves felt not only in the accumulation of surplus water in the body, but also in its re-distribution. In the presence of marked edemas the total water level rises both at the expense of extra- and intracellular water. With the normal level of total water the extracellular water fraction is up and the intracellular one is down. An early and consistent sign of circulatory insufficiency is a drop in the amount of overall metabolic potassium in the body. The potassium deficit increases parallel with progressing circulatory insufficiency, being contingent not only upon the reduction of the cellular mass, but also on the lower intracellular concentration of potassium. The concentration of potassium in the plasma does not reflect the overall content of it in the body.
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Processes of fluid exchange in the crystalline lens of the rabbit eye were investigated. The direction of movement of fluid in the crystalline lens was investigated from the movement of fluorescein by the method of "stopped diffusion". It has been found that the mechanism of fluid transport in the crystalline lens is active and is carried out by means of the Na-kappa-ATPase transport system. The energy necessary for the active transport of fluid inside the crystalline lens is in the range (1.5-6) x 10(-2) J. Owing to the active fluid transport, the pressure inside the crystalline lens constantly increases by 6 mm Hg. In rabbit's life-time, the movement of fluid in the crystalline lens occurs in the direction from the anterior to the posterior surface followed by the exit to vitreous humor.
The structure and function of the intercorneocyte cement of the corneal layer of epidermis in mammals has been reviewed on the basis of the author's and published data. Two functions of the layer have been considered: a water-tight barrier and a desquamation. Chemical structure of the barrier has been characterized. Comparison of the barrier in water and terrestrial mammals suggest that the peculiarities of the barrier correlate with different pathways of keratinization. Factors that determine the adhesion have been described. The authors show the possibility to use natural models for studying the processes of keratinization and, in particular, functioning the intercellular compartment of the corneal layer.
Quantitative and qualitative composition of gangliosides, sulfatides and cerebrosides were studied in normal state and in experimental brain edema by means of thin-layer chromatography. In the experimental edema content of mono- and disialogangliosides was decreased while tri- and tetrasialogangliosides were unaltered. Statistically distinct increase in content of sulfocerebrosides (sulfatide 1.2) was also detected in brain edema as compared with controls. At the same time, amount of cerebroside 2 was decreased, whereas increase in cerebroside I concentration was detected.
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The Harderian gland and glands of the oral angle structure and processes of secretion in the common hamster have been studied under light and electron (scanning and transmission) microscopes. Both these glands were shown to be lipid-producing. Nevertheless, their epithelial cells differ in ultrastructure. The Harderian gland has tubulo-alveolar architecture and consists of two types of epithelial cells. The oral angle gland is acinar and contains differentiating cells of the third type. The possibility of synthesis of various lipids by these three types of cells is discussed.
The structure of harderian glands was studied using electron microscopy and histochemistry in six rodent species, including three Phodopus species. Based on the concept of cell morphotype it was shown that the harderian glands of the studied mammalian species are lipid-secreting and have secretory cells of the species specific morphotypes. The secretory cells are distinguished by the ultrastructural features not only between different genera, but also between different species of the same genus. The data obtained allow species identification according to the ultrastructure of secretory cells. The role of harderian glands in chemical communication was shown for the golden hamster (Mesocricetus auratus). Their secretory substance contains information about the sexual and species identity of animals.