[Life extension study on high-yield non-myeloablating bone marrow transplantation from young to old mice].

Tissue renewal is the known phenomenon, when the progeny of resident or circulated stem cells (SC) replaces the vanishing cells. The delivery of stem cells via circulation should result in stem cell homing and differentiation into wide variety of tissues and gives promise as therapy for many diseases of tissue failure including aging itself. To test this hypothesis, we created chimeric mice C57BL/6 by bone marrow (BM) transplantation from young 1.

[The status of nucleolus organizing regions in hybrids of pluripotent and somatic mouse cells cultured under different conditions].

In the present work we examined the status of nucleolus organizing regions of mitotic chromosomes (NOR) in hybrid cells obtained by fusion of the mouse teratocarcinoma cells PCC4aza1 and adult mouse spleenocytes upon cultivation of hybrid cells under different conditions. We have shown that extended cultivation of hybrid cells in medium supplemented with HAT (hypoxanthine, aminopterin, thymidine) promotes the maintenance of NO-chromosomes, whereas under nonselective conditions elimination of NO-chromosome occurs. In nonselective medium the number of active, i.

[Growth and differentiation of cell hybrids obtained by fusing mouse PCC4azal teratocarcinoma cells and mouse spleen cells under different in vitro culture conditions].

Cell hybrids obtained by fusing mouse PCC4azal teratocarcinoma cells and spleen cells induced to proliferation and treated with the demethylating agent 5-azacytidine prior to fusion are described. The obtained hybrids demonstrated no expression of T lymphocyte marker genes CD11 and CD45, which indicates possible somatic nucleus reprogramming by factors present in teratocarcinoma cells. Irrespective of culture conditions, cell hybrids demonstrated a relatively stable chromosome number: they lost on average no more than four chromosomes after 30 passages.

[Expression of human interferon beta in the mammary gland of transgenic rabbits].

A biotechnological system for the production of human beta interferon was developed on the basis of a hybrid gene constructed from the coding sequence of the beta interferon gene inserted into the first exon of the sheep beta lactoglobulin gene. It is intended for the expression of human beta interferon in mammary glands of transgenic animals. Two lines of transgenic rabbits were obtained using the hybrid gene.

[Activation of nucleolar organizers during in vitro cultivation of mouse R1 embryonic stem cells].

We studies the activities of ribosomal genes (nucleolus forming regions of chromosomes) at successive stages of cultivation of the mouse R1 embryonic stem cells. The total number and number of active nucleolar organizers were estimated by means of in situ hybridization with mouse rDNA probes and argentophilic staining of nucleolus forming chromosomes regions from the 16th until the 32nd passages. The data we obtained suggest that the total number of nucleolar organizers per metaphase plate was constant (as a rule, eight), while the mean number of active nucleolar organizers progressively increased from the early (16th) to the late (32nd) passages: 5.