[Changes of the heart conduction system after exposure to fluorouracil].

Using 20 male rats the electron microscopic study of conducting system of the heart was performed to assess the effect of fluorouracil--an antineoplastic drug belonging to antimetabolite group. A daily dose of 15 mg/kg of fluorouracil was injected intraperitoneally for 5 days; three courses of injections with the intervals of three weeks were performed. Toxic effect of fluorouracil is demonstrated after the first course of injections and is revealed as a predominant injury of pacemaker cells in sinoatrial and atrioventricular nodes.

Presence of a thermostable domain in the helical part of the type I collagen molecule and its role in the mechanism of triple helix folding.

A study has been done of the effect of neutral salts (NaCl and CaCl2) on the mechanism of type I collagen triple helix folding and unfolding in concentrated acetic acid solutions (2-8.8 M). It is shown that in these conditions, thermoabsorption and secondary structure change in heated solutions proceed in two consecutive stages.

Thermodynamic substantiation of water-bridged collagen structure.

A solution of the problem of topology of a hydrogen bond net in a triple helix of collagen is suggested on the basis of an analysis of thermodynamic data on denaturation of phylogenetically different collagen [T. V. Burjanadze (1982), Vol.

An attempt at creating the structure of andrological science.

The cognition and assessment of various spheres of behaviour and vital activity of man are possible only through a systemic approach to its study. It is necessary to point out the different levels of methodological approach to the problem of a successful development of andrology and to determine their tasks and limitations. The main sections of research of andrology must include: medico-biological, philosophic-anthropological, sociological, and psychological investigations of personality.