[Patterns in the spiral formations of insects].

Regular features of spirals of chitinous filaments of tracheas were investigated in 12 species of insects. All species studied were found to have mosaic heterochirality, i.e.

[Effect of autologous marrow transplantation on bone marrow recovery following large-field fractionated irradiation of dogs].

After large-field fractionated irradiation of dogs at a cumulative dose of 54 Gy, a stable bone marrow depletion occurs persisting for a year following irradiation. The automyelotransplantation after the end of the exposure elicits a transient recovery of the exposed bone marrow, 1.5-2 months after the beginning of irradiation, followed by a secondary depletion of the exposed haemopoietic sites.

[Effect of endotoxin on the migration of hematopoietic colony-forming cells and on the repopulation of hematopoietic organs in partially irradiated mice].

In experiments on (CBA X C57BL)F1 hybrids it was shown that the administration of sublethal doses of endotoxin to locally exposed (spleen, 9 Gy) animals enhanced the repopulation of the exposed haemopoietic tissue (spleen and bone marrow). It is concluded that endotoxin has a favourable action on the recovery of haemopoiesis of partially irradiated mice which confirms the idea of the possibility of using stimulators instead of autotransplantation of bone marrow from intact parts.

[Correlation of spleen colony formation and changes in spleen weight during its recovery in irradiated mice].

In experiments on (CBA X C57Bl)F1 and BALB/c mice it was shown that with the spleen mass increasing, due to exo- and endorepopulation, during the postirradiation regeneration of the spleen, the number of splenic colonies also increases to a certain level. When the spleen mass reaches 1/3 of that lost after irradiation the number of discrete colonies decreases. When the spleen mass is restored to about 1/2 solitary colonies do not form at all.

[Morphological changes after large-field irradiation of dogs and autologous bone marrow transplantation].

The effect of an automyelotransplant taken from a nonirradiated area of bone marrow has been studied after large fields irradiation in dogs. Certain changes occurring in the hemopoietic organs and in some other vitally important organs have been revealed. The automyelotransplantation contributes to a quicker repopulation of the bone marrow and stimulates lymphoid hemopoiesis in the spleen; that plays a positive role in overcoming the bone marrow syndrome at radiation illness.

[Effect of immobilization of mice with different radiosensitivities and shielding of part of the bone marrow on survival and spleen colony formation following irradiation].

Experiments on linear F1 (CBA x C57BL) mice resistant to irradiation and random-bred white mice which are more sensitive to irradiation were made to study the relationship of the survival rate of the animals and spleen colony formation to the magnitude of x-ray doses during immobilization and shielding of the crus--factors which increase the resistance. It was shown that low colony formation typical for linear mice remained at a low level during the resistance-increasing immobilization, while in the course of shielding it increased in accordance with the animals' survival rate. In random-bred mice, the survival rate and colony formation were in good agreement in all the cases.

[Hematopoietic stem cell migration study in dogs].

The migration rate of stem hemopoietic cells (SHC) of the bone marrow was studied by two methods in experiments on 54 dogs. In the first case the dogs were irradiated with an absolute lethal dose (550 R) subtotally, shielding two knee-joints. Seven days after the first irradiation under inactivation of shielded parts with 2000 R dose the survival rate was 12.

[State of several rat hematopoietic organs following total and subtotal irradiation and after bone marrow autotransplantation].

Hemopoiesis was studied in rats after x-ray irradiation. Lethal doses of 800--820 R were applied totally, with screening the shin and with subsequent autotransplantation of bone marrow taken from noninjured hemopoietic tissue. Survival of the animals and status of hemopoietic organs (quantitative indices of the peripheral blood, bone marrow and the spleen, as well as morphological changes in hemopoietic organs) served as tests.

[Use of autologous bone marrow taken from a shielded area at different times after irradiation].

It was shown that in X-irradiation of rats in the absolute lethal dose (850 R) shielding of the shank saved 32% of the animals from death. Bone marrow autotransplantation from the shielded portion immediately after the irradiation augmented the shielding effect considerably. Such protective action of autotransplantation persists if conducted in the course of the first 5 days after the irradiation, but it decreases later (on the 7th-10th day).