Effect of Embryonic Bone Tissue on Bone Regeneration

Fragmented embryonic bone tissue stimulates bone regeneration. Bone formation starts not from implanted embryonic fragments, but in intact periosteum and endosteum containing cambial cells of the osteodifferon. In rabbits, recovery of damaged radial bone after implantation of fragmented embryonic bone tissue into bone defect was associated with a pronounced periosteal reaction and focal resorption of intact ulnar bone. Consolidation of damaged radial bone without implantation of fragmented embryonic bone tissue was incomplete in all experimental animals.     

Antitumor activity of normal bone marrow cells

After separation of normal murine bone marrow cells in a Percoll density gradient cellular fractions with densities of 1.076 and 1.060 g/ml are capable of suppressing thein vitro growth of leukemia cells. The cytostatic activity of these fractions, however, does not surpass the level of antitumor antiproliferative activity intrinsic to intact bone marrow cells. These cells were found to be capable of joining the splenocytes, thymocytes, and lymph node cells in effector cytostatic cooperation and thus enhance the final antitumor effect. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 8, pp. 181–183, August, 1995     

Androgen metabolism in malignant and benign bone tumors

The comparison of activities of the key enzymes of androgen metabolism in morphological variants of bone sarcomas and benign tumors suggests that malignant tumors of different histogenesis not only metabolize the main androgen testosterone, but also inactivate 5α-dihydrotestosterone, the main regulatory androgen in bones. It is possible that androgen metabolism in bone tumors is aimed at the formation of other androgens, in particular, 3α-and 5β-diols, which can be involved in regulatory processes in bone tissue. Further studies will disclose clinical significance of androgen metabolism and individual androgens in human bone tumors. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 1, pp. 90–92, January, 2000     

Adaptive capacity of granulocytic bone marrow stem cells in preleukemic AKR mice

In leukemia-prone AKR mice, adaptation to 10-h immobilization stress increases the content of sialoadhesin-positive macrophages to the level of intact (CBA×AKR)F₁ hybrids. Hybrid mice responds to stress by a slight reduction of this parameter. The contents of granulocytic hemopoietic islets and committed granulomonocyte precursors in the bone marrow after stress undergo opposite changes. Unlike hybrids, granulocytopoiesis in AKR mice is not activated by stress. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 2, pp. 151–154, February, 1999     

Comparative study of the state of bone tissue during hormone replacement therapy and transplantation of human fetal tissues in oophorectomized women

The state of bone tissue is studied in 95 women with postoophorectomy syndrome. It is shown that fetal tissue therapy delayed the progression of the pathological process in bones and even increased bone density. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 10, pp. 428–430, October, 1995     

Effects of exogenous glucocorticoids on colony-forming activity of the bone marrow under cytotoxic exposure

Experiments on CBA/CaLac mice receiving a half-maximum tolerated dose of 5-fluorouracil demonstrated an inhibitory effect of physiological concentrations of dexamethasone (127×10⁻⁹M) on colony-forming activity of erythroid and granulomonocytic precursors in intact and regenerating bone marrow. Dexamethasone exhibited protective effects on granulocyte, macrophage, and fibroblast precursors during maximum myelosuppression. Various responses of hemopoietic progenitor cells to exogenous corticosteroidin vitro are probably determined by their functional state. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 4, pp. 412–414, April, 1999     

Functional activity of blood mononuclear cells during regeneration of bone tissue

It is established that, during elongation of a segment of the extremity, normal regeneration of the bone tissue is attended by a slight decrease in monocyte adherence during the postoperative period and by an increase of the functional activity of lymphocytes during subsequent activation of osteogenesis. Suppression of the lymphoid apparatus is observed in the case of disturbed osteogenesis. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 1117, N ^o 1, pp. 104–105, January, 1994     

Self-support of induced bone tissue

Ability of osteogenic precursors of bone marrow from intact and induced (by implantation of decalcified bone matrix) bones to support themselves was compared by transplantation in diffusion chambers. Osteogenesis continued for several months in bone marrow transplants from intact bones whereas in transplants from induced bone tissue active osteogenesis, although still observed after 12–20 days, ceased after 2 months. Fibroblasts from the second passage from cultures of hematopoietic tissue of induced bones, unlike fibroblasts from cultures of intact bone marrow, were virtually without osteogenic powers. These results confirm that induced osteogenic tissue has limited ability of self-support after the action of the inducer has ceased, compared with intact bone tissue.N. F. Gamaleya Institute of Epidemiology and Microbiology, Moscow, (Presented by Academician of the Academy of Medical Sciences of the USSR O. V. Baroyan.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 2, pp. 239–242, February, 1976.     

Effect of regeneration of the spleen and bone marrow on number of hematopoietic colonies in the mouse spleen

Two thirds of the spleen (group 1) or the bone marrow from the right tibia (group 2) was removed from sexually mature male CBA mice. On the eighth day after lethal irradiation and injection of 1·10⁶ nucleated cells from the intact spleen the number of hematopoietic splenic colonies was counted. A significant increase in the number of colonies was observed in the animals of both experimental groups compared with the control intact mice. the authors suggest that this increase may have been caused both by the local effect of the regenerating splenic stroma and by a certain stimulating factor secreted by the regenerating hematopoietic tissue.Laboratory of Growth and Development, Institute of Human Morphology, Academy of Medical Sciences of the USSR, Moscow. Department of Histology, Biological Faculty, Moscow State University. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 11, pp. 1375–1376, November, 1976.     

Use of osteogenic bone-marrow precursor cells for reparative osteogenesis in the mandible of experimental animals

Using a model of “bony tissue tunnel defect” produced by the removal of a mandibular incisor in rats, it was found that closing the defect with a bioprosthesis prevented the washing out of osteogenic bone marrow precursor cells, which serve as a substrate for reparative osteogenesis, from the mandibular spongy bone. The reparative process was strongly stimulated if the bioprosthesis contained estrone; in this case, the time required for the tooth socket to be filled with osteogenic tissue was shortened by half. When no bone marrow elements were present in the socket, it was filled with fibrotic connective tissue, the number of bone marrow elements in spongy bone cavities was small, and the mandibular osteogenic tissue underwent atrophy. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 1, pp. 72–75, January, 1995     

Rapid and complete cellularization of hydroxyapatite for bone tissue engineering

Using a tissue construct generated by cells in a scaffold in reconstructive surgery, as a substitute for autografts, is still challenging. Routine methods of incorporating cells into scaffolds are either passive, i.e. by gravity, or forced, as in a bioreactor. Extensive use of these methods is obstructed by tissue formation around the scaffold, hindrance in cell penetration and time required for cell coverage within the scaffold. In this study, human osteoblast cells as cell sheet structures were seeded to porous and dense hydroxyapatite with the hypothesis that preservation of native extracellular structures and cell-cell contacts would facilitate the cellularization process. Cellularization was assessed by fluorescence, confocal and scanning electron microscopy at intervals of 1 h, 2 days and 7 days. Cell patches with intact cell-cell and cell-extra cellular matrix contact attached and adhered on a scaffold within 1 h. The patches formed a monolayer within 2 days and complete cellularization of the scaffold was attained in 7 days. Cell viability, proliferation and function were assessed to understand the application of cell patch transfer to bone substitute. This novel approach for application in bone tissue engineering was successful in uniform distribution of intact osteoblast cell sheet structures on to bone substitute materials for rapid and complete cellularization without altering material characteristics.     

Effect of combined injection of hydroxyapatite and estrone on dental well healing

Combined injection of hydroxyapatite and estrone stimulates bone tissue regeneration in albino rats with tunnel defects of bone tissue after removal of mandibular incisors.³H-thymidine autoradiography demonstrates that bone tissue regenerates due to proliferation and differentiation of osteogenic bone marrow precursor cells and connective tissue pericytes. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 123, No. 6, pp. 693–697, June, 1997     

Association of genetic variation of the RIL gene,encoding a PDZ-LIM domain protein and localized in 5q31.1, with low bone mineral density in adult Japanese women

Twin and family studies had shown that genetic factors are important determinants of bone mass. Multiple genes might be involved. One candidate gene, the reversion-induced LIM gene (RIL), is a PDZ and LIM-domain-containing protein and has been localized within the cytokine cluster of chromosome 5 (5q31.1). In a genetic study of 370 adult Japanese women, we investigated the correlation between radial bone mineral density (BMD) and a genetic variation (−3333T→C) of the 5'-flanking region of RIL gene. A significant association was identified between the RIL variation −3333T→C and radial BMD (r=0.15, P=0.003). The variation of the RIL locus may be an important determinant of osteoporosis.     

Cytological characteristics of red bone marrow of BALB/c mice after implantation of human fetal tissues

Changes in erythroid and myeloid hemopoietic stems, T and B lymphocyte counts, and cell mitotic activity were observed in red bone marrow of BALB/c mice injected with human fetal tissues (placental extract and fetal liver suspension). The changes depended on the time postimplantation and, to a lesser extent, on the type of fetal tissue. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 3, pp. 340–343, March, 2000     

Growth-inhibitory activity of bone marrow cells during CCl4-induced liver cirrhosis

During CCl₄-induced liver cirrhosis, cells of the hemopoiesis-inducing microenvironment in the bone marrow of BALB/c mice produced activity inhibiting the growth of erythropoiesis and granulomonocytopoiesis precursors. Stimulation with yeast polysaccharide zymosan increased the inhibitory activity (especially in relation to granulomonocytic precursors). The highest growth-inhibitory activity was produced by the bone marrow adherent fraction (residual bone marrow macrophages). Tumor necrosis factor-α is probably responsible for the inhibition of the growth of myeloid precursors in mice with CCl₄-induced liver cirrhosis. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 6, pp. 645–647, June, 1999     

Suppressive and antitumor activities of bone marrow cells and splenocytes of AKR mice during aging

In 4-month-old leukemia-prone AKR mice, the ability of bone marrow cells to inhibit proliferation of concanavalin A-stimulated splenocytes and mastocytoma P815 cellsin vitro was sharply increased in the preleukemic period. In 7-month-old mice, differences in natural suppressive activity of bone marrow cells were significant, but less pronounced than in 4-month-old mice. The immunosuppressive activity was not found in the spleen. In 4-month-old AKR mice, in the inhibition of proliferation of mitogen-stimulated splenocytes was increased due to enhanced NO production by bone marrow cells. These findings suggest that the increased antiproliferative activity observed in the bone marrow of AKR mice long before the appearance of clinical manifestations of leukemia is associated with disturbances in differentiation of myeloid progenitor cells and accumulation of natural suppressor cells in the bone marrow. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 4, pp. 452–454, April, 1999     

Structural organization of the bone mineral

Structural organization of the bone mineral phase formed by intra- and interfibrillar lamellar crystals is studied by scanning electron microscopy and cryofractography. Rod-shaped crystals are found only in collagen fibrils of the bone lacuna walls. Intra- and interfibrillar crystals form numerous contacts, ensuring the integrity of the bone mineral phase. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 12, pp. 687–691, December, 1996     

The effect of a new 9-aminoacridine derivative on working and long-term memory in rats

The effects of Vp, a new 9-aminoacridine derivative, on the radial maze performance of intact and scopolamine-treated rats were compared with those of amiridin and tacrine. In intact rats Vp improved the formation of long-term spatial memory and has a positive effect on working memory at the initial stage of training. In scopolamine-treated rats Vp reduced the amnesic effects of scopolamine on both kinds of memory. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 127, No. 2, pp. 202–204, February 1999     

Biodegradation and restitution of the intercellular matrix in preserved fragments of dense fibrous connective tissue after their grafting into the recipient

Results are presented from a study in which the structural arrangement of the intercellular matrix was examined in preserved connective tissue fragments (allografts) after their implantation into rabbits to repair posttraumatic space-occupying defects in the capsular-ligamentous complex of the knee joint. Stages of biodegradation and restitution undergone by the interstitial substance of connective tissues after the implantation of allografts are identified. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, N ^o 1, pp. 20–23, January, 1996 Presented by G. N. Kryzhanovskii, Member of the Russian Academy of Medical Sciences     

Effect of amiridin on the conditioning of rats in a radial maze

The effect of amiridin and of the reference preparations tacrine, picamilon, and piracetam on conditioning in a radial maze is studied in intact rats. Long-term memory was significantly improved by amiridin, tacrine, and picamilon. Short-term memory was enhanced only by picamilon. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, No. 5, pp. 526–527, May, 1996