[Smoking as an additional risk factor for the staff of chemically hazardous production facilities].

One of the factors that increase the risk of genotoxic effects in the staff of chemically hazardous production facilities is smoking. There was performed the cytogenetic study in 104 males working with highly toxic chemicals, 71 people out of which were smokers and 33--non-smokers. No statistically significant differences were revealed between groups of smokers and nonsmokers. Among smokers 39 males smoked more than 15 cigarettes per day and were referred to the group of "heavy smokers", 32 cases were light smokers (less than 15 cigarettes per day). The level of chromatid exchanges and exchange of chromosomal aberrations (dicentric and ring chromosomes, atypical atypical monocentrics) in the group of "heavy smokers" were shown to be significant higher than in non-smokers and light smokers groups. Our data confirm the synergistic effect of smoking and the factors of increased chemical hazards.

[Cytogenetical alterations in the workers of higher chemical hazard enterprises in accordance with duration of the employment period].

Cytogenetical examination was performed in 135 workers of higher chemical hazard enterprises with the duration of the employment period from 1 to 23 years. Weak, but statistically significant correlations were observed between indices: the total rate of chromosome aberrations (CA) (Tau = 0.14, p < 0.05), the rate of single fragments (Tau = 0.12, p = 0.01), the rate of ring chronosomes (Tau= 0.12, p = 0.04), the rate of double fragments (Tau = 0.13, p = 0.02), the rate of chromosomal exchange aberrations of chromosome type (Tau = 0.13, p < 0.03) and "the rate of multiaberrant metaphases" (Tau = 0.2, p = 0.0008) and the duration of the employment period at the higher chemical hazard enterprises. The rates of all types of CA was significantly higher in the group with duration of the employment period more than 5 years the significant exceedance of the control level was observed only for the total rate of CA and the rate of single fragments. Other CA types do not significantly exceed control indices. The ratio of carriers of CA of exchange type in the long standing group was significantly higher than in the short standing group, in that ring chromosomes were observed in the long standing group. Differences in the ratio of persons with the normal and increased levels of CA were statistically significant.

[The mechanisms of stimulation of cellular proliferation under the effect of L-amino acids in the tissue culture in young and old rats].

The statistical method of range correlation was used to analyse the correlation of individual characteristics of L-amino acids, as well as of the dipole moments of the first pair of the nucleotides of their codons to the biological activity of the amino acids, i.e. to the stimulation of the cellular proliferation. The experimental material was obtained in the organotypic tissues of ecto- and mesodermal genesis in young and old rats. It was demonstrated, that each of stimulating amino acids acts in the explants from old rats to 1,5-6 times rarely, as compared to the explants from young rats. The weak correlation was detected between the stimulation of the cellular proliferation and physical-chemical characteristics - hydrophobicity, dipole moment and isoelectrical point of the amino acids, - in many tissues, but high and moderate correlation was detected in the brain subcortical explants, cerebella and skin. However, the moderate close correlation was detected between the dipole moment of the first pair of the nucleotides of their codons and the stimulating activity for the explants of the brain subcortical structures (young and old rats), of cerebella and skin (young rats), Spearman correlation coefficient rS =0,52; 0,45; 0,60, 0,71 accordingly. The moderate close correlation was detected also for the explants of testis and cartilage. It can be suggested, that some physical-chemicaland biochemical characteristics of amino acids should correlate to their biological activity, especially in relation to the ectodermal tissue.

Effect of amino acids on expression of signal molecules in organotypic culture of the spleen.

Opposite effects of amino acids on proliferation and differentiation of immune cells in organotypic culture of the spleen were demonstrated. It was found that methionine stimulates differentiation of CD5(+) lymphocyte precursors into T-helpers, cytotoxic T lymphocytes, and B cells and induces proliferation of CD68(+)-macrophages. Glutamic acid and arginine induce proliferation of B cells, while histidine and leucine promote differentiation of precursors towards cytotoxic T cells. The opposite effects of amino acids on immune cells of the spleen are related to different hydrophobicity of their side chains determining the type of intermolecular interaction.