[Molecular nature of regulating cell division and differentiation in an organism].

A short review of the investigations of contactins, tissue-specific compounds providing intercellular contacts, which were discovered by the authors in the 60s, is presented.

[Behavior of magnetic particles of metallic iron in animals].

Intraperitoneal introduction of 5-8 mu ferromagnetic iron particles into mouse leads to their capsulation in the liver and preservation in the organism during no less than 1 month. We have observed activation of peroxide lipid oxidation during 3-4 days after the introduction of particles and a two-fold increase of the free iron content in the liver. Intraperitoneal introduction of ferromagnetic particles with diameter below 1 mu produced rapid death.

[Stability threshold of a tissue system].

Studies of changes in the cells adhesive force during spontaneous and induced cancerogenesis, as well as under the effect of cancerogenesis promotors permits to reveal the cells adhesion forces critical values which separate tissue states stable and unstable to blastomogenesis. These data are analysed proceeding from the concepts on generalized cooperative transitions in the membranes and their role in the control over biological systems. It is taken into account that the membranes and cytoskeleton elements are the most important systems of the tissue mechanical integration, and phase transitions proceeding in them must be reflected in the tissue mechanical properties.

[Action of carcinogenesis promoters on the adhesive force of cells in the liver, lung and thyroid gland in rats and mice].

The short-term effects of the carcinogenesis promoters on the adhesive force of cells are compared with the data from literature on their ability to exert a promoter action on the carcinogenesis development in the same organs during prolonged introduction after an initiator. The ability of substances to decrease the adhesive force in the tissue below the resistance threshold is established to correlate with its promoter activity. The coincidence of tissue specificity of both effects and active doses of substances is observed.