[Dynamics of proliferating cell populations during exposure to periodic phase-specific factors].

Dynamics of the numbers of population of proliferating cells under periodic phase-specific cytotoxic effect with and without blocking action was studied on the basis of a mathematical model. It has been shown that at real values of the model parameters after the beginning of the effects the population number exponentially depends of time. Dependence of the population number dynamics on integral parameters of the cell cycle and the exposure regime was studied.

[Resonance nature of the relation of mouse survival to the interval between administrations of the S-specific agent--hydroxyurea].

The dependence of murine survival on the intervals between periodic hydroxyurea (HU) injections was studied. The single dose of HU comprised 250 mg per kg. Intervals between injections varied from 5 to 19 hours while their number changed from 6 to 9 in different experiments.

[Relation between the toxic killing of mouse small intestine enterocytes and the interval between the administration of the S-specific agent hydroxyurea].

The dependence of small intestinal lesions on the interval between repeated regular injections of hydroxyurea was studied. The doses of 1 g/kg and 0.2 g/kg were used.

[Optimization of the exposure of normal and transformed cell populations to phase-specific agents].

Dynamic behavior of stem cells population of the "critical" tissue (normal population) and tumor cell population under periodic treatment with a phase-specific cytotoxic agent was considered. The results were used for optimization of anticancer chemotherapy. The schedules of treatment were found which provide a maximum rate of tumor-cell elimination for any given rate of the normal population size decrease.

[Classical and non-classical DNA conformations].

All possible right and left double helical structures which may exist in short fragments as well in polymeric DNA have been obtained on the basis of a developed rigorous and accurate method of conformational analysis of DNA. In polymeric DNA only right regular double helices are possible with preference of B-form that is the main biological form of DNA. In contrast, for short fragments the left and right helices have practically the same energies providing some physical ground for side-by-side form, which biologically is possible as a recombination form and maybe as a replication form.

[Relation of the survival of mouse hematopoietic stem cells to the interval between periodic injections of hydroxyurea].

The dependence was studied between the survival of proliferating hemopoietic stem cells (CFUs) on the interval between regular multiple injections of hydroxyurea (HU). Before HU injection mice were irradiated in a dose of 200 rad to trigger the proliferation of CFUs. The dependence obtained is resonance in character, with a maximum being attained during injections made with a 12-hour interval.

[Possible DNA conformations].

The complete analysis of possible DNA structures has been undertaken in the space of dihedral angles. The structural sets obtained join energetically and geometrically possible conformations. Thus, the necessary condtions of existence are fulfilled for these structural forms.

[Denaturation temperature of collagen as a linear function of its amino acid composition].

TD of collagen have been constructed as linear function of fractions of each from 18 amino acids using experimental data for 29 proteins. For coefficient estimation the least squire method have been used. As a result the TD of any collagen may be calculated by using of the function obtained.