[Changes in immunocompetent cells under exposure to ionizing radiation]. / Izmeneniia immunokompetentnykh kletok pod vozdeistviem ioniziruiushchei radiatsii.

The modern knowledge concerning radiosensitivity of immunocompetent cells and intracellular changes is discussed in the review. A conclusion is made about the results of irradiation which are not easy to interpret. They depend on the cell type, functional state, and some other factors and conditions. The situation must be taken into consideration when developing the problem about treatment of post-irradiation changes.

[Immune system status under effect of low levels of ionizing radiation:studies within the 10 kilometer zone of accident at Chernobyl nuclear plant]. / Sostoianie immunnoi sistemy pri vozdeistvii malykh urovnei ioniziruiushchei radiatsii: issledovaniia v 10-kilometrovoi zone avarii na ChAES.

A study was made of the influence of high radiation contamination within the ten-kilometer zone of Chernobyl disaster on the structure and function of the immune system of (DBA x C57B1)F1 and DBA mice. The cumulative radiation doses with respect to gamma-radiation, were 0.024, 0.168 and 0.336 Gy. T-lymphocyte proliferation was shown the be activated with all radiation doses mentioned above but with doses of 0.024 and 0.168 Gy, helper T lymphocytes, and with 0.336 Gy, suppressor N-lymphocytes were primarily activated. So, in the former case, some effector functions of the immunity were activated, and in the latter, inhibited. It is concluded that certain hyperstimulation of the lymphoid cell formation (including the increase in T-suppressors), that is induced by long-term exposure to low-level radiation, triggers the mechanisms of autonomous regulation of the system that suppress the radiation-induced lymphocyte proliferation and inhibit the effector functions of the immunity.

[A possible role of neuroimmunoendocrine interactions and development of post-irradiation pathology]. / Vozmozhnaia rol' neiroimmunoéndokrinnykh vzaimootnoshenii i formirovanii postluchevoi patologii.

On the basis of the literature a postulate is proposed that the immune system contributes to regulating the intensity and direction of endocrine and nervous system functions in normal conditions and after the effect of ionizing radiation. The role of neuroimmunoendocrine interactions and their impairment in the realization of stochastic and nonstochastic sequelae of irradiation at various levels of radiation affecting the organism under normal conditions and in a combination with other unfavourable factors.

[Cessation of ovarian cycles in a young mouse while in parabiosis with an older one]. / Prekrashchenie ovarial'noi tsiklichnosti u molodoi myshi pri parabioze ee so staroi.

Female mice 3 and 22-24 months of age were jointed in heterochronic parabiosis. That led to permanent estrus in young mice and maintenance of intact anestrus in old mice. After 8-9 weeks of parabiosis there appeared morphological signs of accelerated ageing in the ovaries of young animals, while no changes in the ovaries of old mice were observed. Serum progesterone of young partners decreased to the levels of old animals and estradiol levels remained unchanged, while prolactin content in adenohypophysis was the same as in young single animals but exceeded the level noted in young mice in parabiosis with young partners. Hormone content in old parabionts remained unchanged, as compared to the control. An old organism is thought to be the source of unidentified factors suppressing the ovarian function in young animals.

Functional rearrangement of lymphohemopoietic system in heterochronically parabiosed mice.

This study examines some characteristics of the lymphohaemopoietic system of heterochronically parabiosed CBA mice. It was found that a decline of the primary immune response in a young mouse sutured with an old one is accompanied with the diminution of: bone marrow and thymus cellularity; thymus weight; haemopoietic stem cells (CFC-S) and granulocyte-macrophage precursor cells (CFC-C) contents in the femur, and stromal precursor cell (CFC-F) contents both in the femur and thymus. All the indices tested, including the immune response level, in old parabionts vs. old single mice remained unchanged. In the spleen, the considerable variations of splenic weights in the mice of different control and experimental groups have been found. At the same time, no significant changes in the cellularity and CFC-F number in the spleen of all examined groups of animals have been observed. The findings strongly indicate the considerable rearrangement of lymphohaemopoietic and stromal tissues in the central organs of the immune system, namely, bone marrow and thymus of young mice due to the parabiosis with old ones.

[Mechanism of immune response inhibition during parabiosis of animals of different ages]. / Izuchenie mekhanizma ugneteniia immunnogo otveta pri parabioze zhivotnykh raznogo vozrasta.

Experiments were made of CBA mice aged 4-5 and 24-27 months under 2-months heterochronic parabiosis to determine the primary immune response to administration of sheep red blood cells. One and three months after parabionts separation the magnitude of the immune response did not significantly differ from that of non-separated parabionts and approximated the immune response in old mice. Splenectomy in old partners did not remove the inhibitory effect on young parabionts. X-Ray irradiation of old parabionts 3-5 days after coupling with young ones caused an appreciable recovery of immune function both in old and young partners.

[Primary immune response in parabionts of different ages]. / Pervichnyi immunyi otvet u parabiontov raznogo vozrasta.

Potential mechanisms of aging of the immune system were studied in experimental heterochronic parabiosis of CBA mice. Vascular anastomoses were formed between parabionts thus providing an exchange of the humoral and cell factors and repopulation of lymphoid organs by the partner cells. Investigation into the primary immune response to sheep red blood cells has shown the suppression of antibody production in young partners to be the result of the old body influence. The effect of stimulation of the old immune system by the young animal, however, was only slightly pronounced. It is suggested that the factors actively suppressing the immune response of the young animal may exist in the old body.