[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.

[Immunomorphological lymphocytic-tissue associations in the anterior gastrointestinal tract in human fetus].

Prevalence of T-cell system of the immunity is found in the pharyngeal, lingual and palatine tonsils and lymph nodes. B-lymphocytes are much less numerous. Adenocytes consolidation in the structure of "pharyngeal hypophysis" is considered as additional part of the anterior hypophysis. The structure of the mucous membrane in the region of pharyngeal hypophysis is described. This membrane is deprived of protective epithelium and mucous glands.

[Histophysiology of lymphocyte-tissue complexes in human fetal intestine].

Using histochemical and immunological methods, the development of lymphocyte-tissue complexes in the distal part of human fetal intestine (appendix, Peyer's patch) was studied in relation to the changes taking place in the ileocecal lymph nodes. It was found that this autonomous gut immune system started to function in the second trimester of fetal development. It is dominated by T-cell system of the immunity. After the appearance of meconium in the intestinal lumen, the phenotypical diversity of lymphocytes within the organ was increased, but it did not reach the level found in mature organism. The ileocecal lymph nodes are distinguished by their lymphocyte composition as a T-cell depot in this interorgan and intertissue system, which provides essential homeostasis of the developing fetus.

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.

Embryological approach to studies of stem cells.

Based on the findings of their own studies on embryonic histogenesis of human tissues and published reports, the authors determined the time limits of the existence of human embryonic stem cells and type of their determination in divergent development of tissues in different organs. Realization of genetic information of embryonic stem cells during tissue embryogenesis was studied. This information is realized by the cambium. Variability of all tissue processes is possible only within their own embryonic primordium; prospects of the mesenchyma development in an adult body is discussed.

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.

Thymic hormones in human fetal skin epidermis.

Thymic hormone thymalin is detected in young epidermal cells of human fetuses. Its content varies with gestation age. Maturation of keratinocytes in the epidermis is paralleled by a decrease in the population of young thymalin-positive cells. By birth they are located on the basal membrane and in some adjacent layers. This regularity was seen in different parts of the body.

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.