[Proliferative and differentiation potential of individual clones derived from bone marrow stromal precursor cells]. / Proliferativnye i differentsirovochnye potentsii individual'nykh klonov stromal'nykh kletok-predshestvennikov kostnogo mozga.

We present the results of a study on the proliferative and differentiation potential of individual clones of stromal fibroblasts growing in monolayer cultures of bone marrow cells. Each precursor cell yielding a large colony in primary culture is capable of up to 34 doublings in vitro. The transplantation of clones or monoclonal strains of stromal fibroblasts into the open system results in the formation of microenvironment consisting of the bone and reticular tissue and is suitable for the differentiation of all three lines of hemopoiesis. Evidence has been obtained that, in a closed system, individual clones are capable of differentiation into the bone, cartilaginous, and reticular tissues. In other words, the adult organism has a common cell precursor for these tissues.

[Differentiation potentials of clonal strains of bone marrow fibroblasts]. / Differentsirovochnye potentsii klonal'nykh shtammov kostnomozgovykh fibroblastov.

The clonal nature of CFUf-derived fibroblast colonies was proved by chromosomal analysis of individual colonies and single-colony-derived fibroblast strains using mixed cell cultures from male and female rabbits. CFUf progeny, forming colonies composed of more than 10(3) cells was capable of 20-30 cell doublings during subsequent passages. When transplanted in diffusion chambers, single-colony-derived fibroblast strains formed bone and cartilage simultaneously. Thus, CFUf or part of them can be regarded as bone marrow osteogenic stem cells.

[Proliferative and differentiation potentials of skeletogenic bone marrow colony-forming cells]. / Proliferativnye i differentsirovochnye potentsii skeletogennykh kostnomozgovykh kolonieobrazuiushchikh kletok.

The clonal nature of bone marrow fibroblast colonies derived from clonogenic bone marrow osteogenic cells (CFUf) was proved by the chromosome analysis. During subsequent passages of multi-colony derived bone marrow fibroblast strains there occurs a pronounced increase in the cell number and in the number of osteogenic units (tested by transplantation in diffusion chambers). Single colony-derived strains are capable of forming bone and cartilage simultaneously. It follows that CFUf or part of them are clonogenic cells with high proliferative potentials and are common precursors for bone and cartilage tissue. Thus, CFUf may be regarded as osteogenic stem cells.

[A count of osteogenic precursor cells in the bone marrow and their multiplication in cultures]. / Soderzhanie v kostnom mozge osteogennykh kletok-predshestvennikov i ikh razmnozhenie v kul'turakh.

The progeny of clonogenic stromal medullary fibroblasts from rabbits was cultivated by repeated passage. As a result of several passages the number of cells under consideration could be raised hundreds of thousand times as compared with the initial cell quantity. The strains of stromal medullary fibroblasts were found to have osteogenic properties; during reverse transplantation to the body they formed osseous tissue, creating the medullary organs. It was shown that during cultivation, the amount of osteogenic units in a cell culture dramatically rose, i. e. the osteogenic precursor cells multiplied and were self-maintained. According to all these signs the clonogenic stromal cells of the bone marrow can be regarded as stem osteogenic cells.

[Morphologic analysis of guinea pig bone regeneration following curettage]. / Morfologicheskii analiz regeneratsii kostnogo mozga morskoi svinki posle kiuretazha.

Interrelation of stromal and hemopoietic elements in the regenerative process of the guinea-pig bone marrow at different time after curettage has been morphologically studied. The bone marrow regenerative process in the depleted medullary cavity of the guinea-pig tibial bone passes through several phases following each other: blood clot formation, rough-fibrillary osseous tissue formation, its resorption, development of sinusoids and formation of reticular stroma with subsequent repopulation of hemopoietic elements in it. The leading role in the process of the bone marrow restoration belongs to the reticular stroma creating specific microconditions for hemopoiesis.

[Bone marrow microenvironment transfer by clones of stromal mechanocytes]. / Perenos kostnomozgovogo mikrookruzheniia klonami stromal'nykh mekhanotsitov.

Clones of bone marrow stromal fibroblasts harvesed from monolayer cultures of mice and guinea pig bone marrow cells are transferring the hemopoietic microenvironment when transplanted in vivo. Individual fibroblast clones form bone tissue and create the microenvironment for erytroid, myeloid and megakariocyte differentiation of hematopoietic cells simultaneously.

[Effect of marrow cavity curettage on bone marrow stromal cell precursors]. / Vliianie kiuretazha kostnomozgovoi polosti na kostnomozgovye stromal'nye kletki-predshestvenniki.

Changes in the number of bone marrow stromal precursor cells of guinea pigs after the bone marrow curettage was studied by cloning in monolayer cultures in vitro. About half of the colony-forming units (CEU-F) is extracted during curettage. Later the number of CFU-F in the curetted bone marrow continues to fall, reaching its minimum in 12 hours. Regeneration begins after 24 hours, and on the 7th--12th day the CFU-F content in the curetted bone marrow reacts the normal level; by the 20th day the number of CFU-F exceeded the normal 2.5 times. The CFU-F content in the contralateral bones of donors exceeded their normal content (at periods from 6 hours to 20 days) 2--2 1/2-fold.

[Origin of stromal bone marrow mechanocytes according to the results of typing them by isoantigens and chromosomal markers]. / Proiskhozhdenie stromal'nykh mekhanotsitov kostnogo mozga po dannym ikh tipirovaniia po izoantigenam i khromosomnym markeram.

The bone marrow of radiochimaeras and heterotopic bone marrow transplants were used to study the origin of precursors of the fibroblasts growing in the monolayer cultures of hemopoietic tissue. In the bone marrow explants of the (C57BL/6 X CBA) F1 mice, in which the CBA bone marrow was transplanted following the lethal irradiation, the fibroblasts grown in the colonies were of recipient origin judging by isoantigens in the reaction of indirect immunofluorescence with the anti-C57BL/6-serum. At the same time in the bone marrow explants from heterotopic transplants (CBA leads to CBA X C57BL/6) the fibroblasts grown in colonies were of donor origin. The cultures of hemopoietic cells of the bone marrow of females heterotopically transplanted in the singenic male (guinea pigs Huston) contained only fibroblasts which were of donor origin judging by sex chromosomes in the metaphase plates of dividing cells. Hence, the bone marrow precursors of fibroblasts do not depend histogenetically on hemopoietic cells and are not replaced at the expense of repopulating cells of the second partner.