The cellular composition of the cerebral cortex of rat fetuses after fractionated low-dose irradiation.

Histological and morphometric studies were performed to address the characteristics of the morphogenesis of the sensorimotor cortex of the brain in rat fetuses subjected to fractionated gamma irradiation during the period from day 6 to day 18 of antenatal development at doses of 5, 25, 30, and 75 cGy. The results showed that fractionated irradiation at doses of 5-75 cGy had adverse effects on the processes of stem cell proliferation in the tissues of the developing cortex and also increased the intensity of cell destruction proportionally to the radiation dose. All cellular zones of the developing cortex showed increases in the absolute number of macroglial cells, which may be associated on the one hand with reactive increases in their production due to functional deficiencies and, on the other, with accelerated transformation of radial gliocytes into macroglial cells. Irradiation at doses of 5-75 cGy decreased the rate of migration of neuroblasts into the primary cortex, as shown by decreases in the numbers of cells in the neural differon in the neocortical rudiment and increases in their levels in the deep layers of the developing cortex.

[Cellular composition of cerebral cortex in rat fetuses exposed to low-dose fractionated radiation]. / Kletochnyi sostav kory bol'shogo mozga plodov krysy v usloviiakh fraktsionirovannogo vozdeistviia radiatsii v malykh dozakh.

Using histological and morphometric methods, the peculiarities of sensomotor cortex morphogenesis were studied in rat fetuses subjected to fractionated gamma-irradiation in the period from 6th to 18th prenatal days in doses of 5, 25, 50 and 25-75 cGy. It that an Exposure to a fractionated radiation was found to negatively affect stem cell proliferation in the developing cortex and to increase the intensity of cell destruction in proportion to the radiation dose. The absolute number of macroglial cells was increased in all the cellular zones of developing cortex, that could be the result of both reactive stimulation of their production due to functional insufficiency, and of accelerated transformation of radial gliocytes into macroglia. Irradiation with the doses of 5-75 cGy caused the deceleration of neuroblast migration into the primary cortex, as indicated by the reduction of cell number in neural differon in the neocortical anlage and cell number growth in deeper layers of the developing cortex.

[The thymus structure during radiation exposure in antenatal ontogeny]. / Stroenie timusa pri radiatsionnom vozdeistvii v antenatal'nom periode ontogeneza.

Peculiarities of thymus morphogenesis were studied in mice subjected to irradiation in antenatal ontogenesis by means of anatomic, histological and morphometric methods. Dosed action of X-ray irradiation up to 25 cGy in sum and stress factors were established not to impair sharply embryonal thymus morphogenesis but is accompanied with reactive reorganization in the organ. Dosed irradiation over 25 cGy in sum caused prognostically unfavourable disturbances of embryonal thymus morphogenesis manifested as hyperplastic and degenerative dystrophy changes.

[The function of the immune, reproductive and endocrine body systems during irradiation under exposure to stress factors of a non-radiation nature]. / Sostoianie immunnoi, reproduktivnoi i éndokrinnoi sistem organizma pri obluchenii v usloviiakh vozdeistviia stress-faktorov neradiatsionnoi prirody.

Diverse indexes of the state of immune, reproductive and endocrine systems were studied by morphological, biomechanical and biological methods under the effect of non-radiation stress factors, accompanying irradiation of the animals and their changes under effect of the ionizing irradiation 7 and 360 sGy in doze. It was demonstrated that short-time extreme effect lead to hormonal homeostasis destabilization, compensatory-adaptive transformations in immune system and also influence the indexes of copulation efficiency and intrauterine losses. Ionizing irradiation modifies the response to stress-factors effect with modification depending on the irradiation doze.

[The cellular composition of the iliac lymph nodes and thymus in mice under local x-ray irradiation of the gonads at high and low doses]. / Kletochnyi sostav podvzdoshnykh limfaticheskikh uzlov i vilochkovoi zhelezy u myshei pri lokal'nom rentgenovskom obluchenii gonad bol'shimi i malymi dozami.

The cellular composition of iliac lymph nodes and thymus of 150 male white mice was studied 4 weeks after local irradiation of the gonads by doses 7.34 and 360 cGr by histological and electron microscopic methods. Intact animals and corresponding groups of false irradiation were used as control. Changes of the cellular composition of B-dependent zones of the lymph nodes were shown both after irradiation by high (360 cGr) and low (7 cGr) doses. The effect of irradiation by the dose 34 cGr on the content of certain cell forms was less while the ultrastructural transformations were more pronounced than those caused by weak X-ray irradiation. Certain similarity was established in the dynamics of cell reactions in false irradiation of the animals (imitation control) and irradiation by low doses. A supposition is put forward concerning the influence of non-irradiation factors accompanying the irradiation on the value and character of the response to radiation loads of low intensity.

[Structure of the thymus, iliac and mesenteric lymph nodes in the rat at different stages of pregnancy]. / Stroenie vilochkovoi zhelezy, podvzdoshnykh i bryzheechnykh limfaticheskikh uzlov u krys v raznye periody beremennosti.

Development of pregnancy results in a systemic reaction of the immunogenetic organs: the structure of both the central (thymus) and peripheral lymphoid organs (lymph nodes) undergoes certain changes, beginning from its earliest stages (preimplantation period). Unidirection of the processes in the iliac (that are regional for the uterus) and mesenteric lymph nodes is stated. The reconstruction of the node occurs according to the reaction type at tissue allotransplantation, when hypertrophy of the thymus-dependent zone comes forward. During the period of the greatest manifestations of these alterations, however (the second half of pregnancy) the migration process of lymphocytes from blood into the lymph node is significantly inhibited. This is essentially clear in the iliac lymph nodes. The reconstruction of the thymus is in general similar with phenomena of accidental involution. However, accumulation of thymocytes in the medulla demonstrates blocking of their discharge into the blood stream. The disturbed processes of recirculation of result in incompleteness of the immune response at pregnancy and, perhaps, are included into the protective mechanisms of the offspring reproduction.

[Cellular composition of various structural zones of the iliac and mesenteric lymph node of pregnant rats]. / Kletochnyi sostav razlichnykh strukturnykh zon podvzodshnykh i bryzheechnykh limfaticheskikh uzlov u krys pri beremennosti.

The dynamic of cellular reactions demonstrates certain changes in functional activity of all structures of the node during pregnancy. A similar trend of processes in the iliac (regional for the uterus) and mesenteric lymph nodes has been defined. At early stages of pregnancy, lymph nodule are the most active, this is demonstrated as an increasing portion of lymphoblasts, macrophages and dividing cells. During this period, cell composition of the cortical plateau is relatively stable. For the paracortical zone of the mesenteric lymph nodes a rather significant decrease in the portion of middle lymphocytes and reticular cells is characteristic. There is not any significant change in the relative amount of the cells in the same functional zone of the iliac lymph nodes during the same period of pregnancy. The medullar cords demonstrate an increasing number of blast forms and young plasmocytes. However, as the pregnancy develops, the structure of the paracortical zone undergoes an essential change--progressively increases the portion of lymphoblasts and large lymphocytes. The blastic reaction in the mesenteric lymph nodes is proved to depend, to some extent, on that in the iliac lymph nodes of the same animal. Mature plasma cells become the dominating cellular element in the medullary cords. At the end of the pregnancy a relative amount of the reticular cells increases in all structural zones of the node.