Regeneration of the liver in mice treated with a mixture of hepatotoxins in delayed periods after bone marrow transplantation.

Possible effect of bone marrow cells on liver regeneration was studied in mice injected with a mixture of hepatotoxins (allyl alcohol and CCl4) in a dose equal to LD50. The mixture of hepatotoxins was used to minimize the restitution regeneration of the liver. The dose of allyl alcohol causing (in combination with CCl4) maximum liver damage was selected beforehand.

Telomerase activity in cells of 9-day-old spleen colonies formed by bone marrow of normal and thymectomized mice.

Telomerase activity was measured in spleen colonies, in progeny of individual 9-day-old splenic CFU formed by the bone marrow from normal (physiological aging) and thymectomized mice. Cells of spleen colonies expressed telomerase activity. No correlation was found between telomerase activity in spleen colony cells and age of animals.

Long-term self-maintenance of hemopoietic precursors in bone marrow culture derived from tumor necrosis factor-deficient mice is not a result of neoplastic transformation.

In long-term bone marrow cultures derived from tumor necrosis factor-deficient mice the total cell production and the total duration of hemopoiesis are increased (the latter is comparable with mouse life span). Telomerase activity in cells of nonadherent fraction of long-term bone marrow cultures from tumor necrosis factor-deficient mice increases with time and peaks after 1-year culturing. Karyotyping of nonadherent and adherent cells of long-term bone marrow cultures revealed instability of nonadherent cells and hyperploidy of the stromal sublayer cells, which attested to the presence of a neoplastic transformation.

Age-related changes in activation of telomerase in the bone marrow of normal and thymectomized mice.

Age-related and thymus-dependent regulation of telomerase activity was studied in the bone marrow of normal (physiological aging) and thymectomized (experimental aging) mice. There was no strong correlation between the age and telomerase activity in bone marrow cells of normal mice. We observed only small individual differences in telomerase activity.