[Reaction of the testicles of old animals on administration of human fetal tissues].

The aim of the work was to study the effect of fetal tissues on histological structure of testicles of the old mice. The data obtained suggest that the implantation of human fetal tissues postponed age degeneration of tissues.

Specific features of the immune response in old recipient mice to cell therapy.

Implantation of somatic cells from autopsy specimens (15-18 weeks gestation) had a modulatory effect on immunogenesis in old mice. Activation of the immune system in recipient animals after administration of somatic cells reflects a multistage influence of test preparation. The observed changes were reversible. A progressive decrease in activation of the immune system in recipient mice was not accompanied by the development of pathological changes. Repeated implantation was required to maintain these processes.

The role of donor and recipient in tissue implantation.

The relationships between embryonic stem and cambial cells in the ontogeny were evaluated on the basis of our data on organ embryogenesis and in vivo implantation of epithelial tissues and published data. We demonstrated the role of recipient tissues in the implantation process. Aseptic inflammation developing in response to the implant activates proliferation of the adjacent donor tissues. Proliferation and differentiation of the implanted donor tissues correspond to inflammation phases in the focus of implantation, are regulated by factors of the recipient organism, and are histogenetically determined.

New data on the involvement of ectodermal epithelium in extrathymic differentiation of human T-lymphocytes.

Thymalin accumulates only in young cells of the skin ectodermal epithelium and mucosa of the anterior portions of the digestive and respiratory systems. After appearance of keratin the cells no longer accumulate thymalin. Similarly as in the thymus, thymalin content in the ectodermal epithelium of the organs is subjected to age-associated involution.

Thymalin in developing respiratory organs of human fetus.

We studied the appearance of immunomodulator thymalin in human respiratory organs during early embryogenesis. Thymalin accumulated in young cells of airway epithelium. In the alveolar part thymalin-positive cells were diffusely spread. Mature T cells (CD3+) and the main regulatory elements (CD4+ and CD8+) were detected during the same period in the lungs in the absence of thymic microenvironment. The function of immune elements forming in fetal lungs is local protection of the fetus from potentially aggressive maternal cells and infectious agents entering the body through the trachea and fetal blood vessels.

Age-related changes of thymalin content in human epidermis.

Immunomorphological analysis revealed the presence of thymalin in human epidermis and in fetal reticuloepithelium. These structures are developed from the common embryonic primordium ectoderm. In embryos and adult humans thymalin is present only in young epidermal cells, which undergo age-related involution. By the age of 70 years, the layer of thymalin-containing cells looks thinned and discontinuous. The content of thymalin, a thymic factor, decreases with age.

[The order of lymphatic organs involvement in developing immune system of human fetus and its significance in perinatal pathology]. / Posledovatel'nost' vstraivaniia limfoidnykh organov v razvivaiushchuiusia immunnuiu sistemu ploda cheloveka i ee znachenie v perinatal'noi patologii.

The liver, thymus, spleen, lymph nodes, palatine and pharyngeal tonsils, appendix and Peyer's patch were studied by morphological and immune methods in more than 100 human embryos of 3 to 34 weeks of development. The order of some organs development in the immune system is established. Key periods in the development of the thymus (5-12 weeks) and 18 weeks when peripheral organs enter the immune system are specified. Inherited perinatal pathology in abnormal lymphocytic composition in the organ is illustrated by the appendix.

[Immunologic characteristics of the thymus of aged CBA mice after implantation of human fetal tissue]. / Immunologicheskaia kharakteristika timusa starykh myshei linii CBA posle implantatsii fetal'nykh tkanei cheloveka.

The effect of human fetal tissues (hypothalamic, liver, spleen, adrenal, ovarian, testicle, uterine, prostatic, gut, placental cells) collected from the fetuses at the 16-22 weeks of prenatal development, on the cytological structure of the thymus of 2-years old CBA mice in 7, 14, 42 and 64 days after start of treatment has been studied using morphological and immunological methods. The data obtained suggest that the implantation of human fetal tissues does not stop totally, but postponed age involution of thymus.

Development of endocrine and lymphocytopoietic functions of the thymus in human embryogenesis.

The endocrine function of the thymus develops earlier than lymphocytopoietic. Thymalin is produced by epithelial cells in the thymus primordium. It is released into the blood and regulates differentiation of T lymphocytes in the liver, the initial hemopoietic organ. The hormonal and lymphopoietic functions of human thymus are united on weeks 7.5-8 of embryonic life.

[Biological capabilities of the thymus of human fetus during normal development and during constant exposure to small doses of radiation after the accident at the Chernobyl power plant]. / Biologicheskie vozmozhnosti timusa ploda cheloveka v usloviiakh normal'nogo razvitiia i pri postoiannom vozdeistvii malykh doz radiatsii posle avarii na Chernobyl'skoo AES.

The literature information and the authors's data are presented on the lability of human fetus thymus changes under extremal conditions. In particular, the source of the thymus development is discussed determining its morphogenetic potencies, the sequences of its endocrine and lymphocytopoietic function appearance. Lymphocytes composition and kinetics of their quantity in the process of fetus development and thymus response to the unfavourable conditions of the mother are presented.

[Effect of low doses of radiation on hematopoiesis in the liver of the human embryo and fetus during the first pregnancy trimester]. / Vliianie malykh doz radiatsii na gemopoéz v pecheni émbriona i ploda cheloveka I trimestra beremennosti.

Percentage and mitotic regimen (mitotic index, mitotic phases, pathological mitosis) of hematopoietic liver cells of the embryos and foetuses (6-12 weeks of development) from females living in normal conditions (Moscow) and in polluted with radionuclides after Chernobyl accident territory of Bryansk region of Russian Federation (towns Novozybkov and Klintsy) are characterized. Moderate but statistically significant (P < 0.05) differences were found in the number of polychromatophilic and oxyphilic normoblasts, basophilic megaloblasts, granulocytes at various developmental stages in the study group compared to the control. No difference was observed in 1992 in the mitotic activity, total number of pathological mitoses and the percentage of binuclear cells. But the spectrum of pathological mitoses, in the contaminated zone, seems to be wider. The mitotic index and the number of cells per 1 mg of organ tissue showed two-fold increase in 1993 in the town of Novozybkov as compared to the control area. The conclusion is made that small radiation doses exert only very slight influence on hematopoiesis in human embryonic and foetal liver of 6-12 weeks of gestation.

[Development of the lymphatic follicles and the differentiation of splenic lymphocytes in the human fetus]. / Razvitie limfaticheskikh follikulov i differentsirovka limfotsitov selezenki u plodov cheloveka.

Spleens of more than 100 human fetuses at the age of 5-34 weeks of development have been studied by means of immunofluorescent methods to identify T- and B-lymphocytes. The spleen lymphatic follicles are detected at the 12th-14th weeks of the embryonal development. Within the same range of time in the mononuclear suspension of the organ T- and B-lymphocytes are defined. The critical period is stated when certain density of lymphocytes and the portion of T- and B-lymphocytes is established in the organ and it is not changed up to the end of embryogenesis. After the 22nd week, the reticular stroma of the lymphatic follicle acquires a complex structure. The following zones can be determined in it: the periarterial where thymus-dependent cells are situated, the zone where thymus-independent cells are situated and the marginal zone surrounding the whole lymphatic follicle.

[Structure of the human spleen and immunomorphologic indices of its lymphocytes during embryogenesis]. / Struktura selezenki cheloveka i immunomorfologicheskie pokazateli ee limfotsitov v émbriogeneze.

The authors studied the development and differentiation of spleen lymphocytes and tissues from 100 human embryos aged 5-34 weeks. T-/E-RFC) and B lymphocytes (IgG plus G cells) were identified by histochemical and immunomorphological methods. The weight and quantitative values of the spleen and lymphocytes are presented. The development of the spleen consists of three periods: 1) an early one (5-8 weeks) when the organ is characterized by a compact arrangement of the mesenchymal cells; 2) 9-11 weeks, when blood deposition function prevails; 3) appearance of lymphopoiesis after 13-14 weeks. Heterogenicity of spleen lymphocytes and the time course of the quantitative changes during embryogenesis are reported. It is concluded that the humans spleen presents a polyfunctional organ even in the embryonal period.

[Structural features of the submandibular salivary gland of gnotobiotic rats]. / Osobennosti stroeniia podnizhnecheliustnoi sliunnoi zhelezy krys-gnotobiontov.

The submandibular salivary gland was histochemically and electron microscopically studied in gnotobiotic and conventional Wistar rats at the age of 15 days--10 months. By the first month of age, the submandibular salivary glands in both groups of animals complete differentiation of their acini, and the gland, according to the type of its secretion, becomes seromucous with predominance of albuminous component in it. Succinate dehydrogenase activity and nonspecific esterase predominate in epithelium of the excretory ducts. At the second month of life some signs of moreasing ductal part of the gland appear in the gnotobiotic rats. This part greatly increases by the 4th--10th month of life, mainly at the expense of twisted granular sections. This increase in number and volume of the twisted granular ducts results in compressing acini and in ultrastructural disorders of granulocytes, with destruction of some mitochondria, increasing number of lysosomes, decreasing size and alterations in character of secretory granules, in structural disorders of the laminar complex. All these manifest depressing secretory function of granulocytes in the gland of gnotobiotic animals.

[Structural and immunomorphological characteristics of the human thymus in embryogenesis]. / Strukturnaia i immunomorfologicheskaia kharakteristika timusa cheloveka v émbriogeneze.

The thymus glands from one hundred of 4--34-week-old human fetuses were studied by the histologic, histochemical, immunomorphologic and electron microscopic methods. The development of the organ is described from the standpoint of systemogenesis. The laying of the gland is defined at the 5th week of the fetus development, and it reflects the features of the epithelium of the head intestine organs. The differentiation of the reticuloepithelium, the population of the gland by lymphocytes and emergence of antigenic specificity on their surface state at the age of 7--8 weeks. The growth zone of the thymus reticuloepithelium, the significance of Hassal's bodies, the appearance and quantitative dynamics of two subpopulations of T-lymphocytes are described. From 11--12 till 34 weeks of fetal development the percentage of T-lymphocytes forming rosettes with sheep red blood cells virtually does not change (70--90%), while the percentage of lymphocytes forming rosettes with their own red cell increases during the same period from 23 to 70%.