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Results for “bone marrow cellularity”

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At least 973 records · Page 54Linked to original sources
PubMed1995

Influence of liposomal muramyl tripeptide phosphatidylethanolamine on the changes of nucleic acids in the blood and hemopoietic tissues of irradiated mice.

Effects of liposomal muramyl tripeptide phosphatidylethanolamine (MTP-PE/MLV) on nucleic acid content, and on DNA synthesis and cellularity in the blood and haemopoietic tissues of mice irradiated with a dose of 6 Gy gamma radiation were studied. It was found that injection of MTP-PE/MLV alone (200 micrograms per mouse; i.p.) resulted in a mild decrease in DNA content in the bone marrow as consequence of cellularity diminution in the femur. At the same time, incorporation of 3H-thymidine into bone marrow DNA increased in comparison to the non-stimulated mice. On the basis of simultaneous increase in RNA and DNA concentration in the blood we assume that the changes of nucleic acids and cellularity in the bone marrow of MTP-PE/MLV treated mice are related to the higher release of nuclear cells into the circulation. In mice irradiated 24 h after MTP-PE/MLV injection the decrease in nucleic acid content was similar to that in unprotected mice within the first three days after irradiation. However, during following days, the recovery of RNA and DNA content and cellularity in the bone marrow and blood proceeded at a much faster rate in mice protected by MTP-PE/MLV as compared to unprotected animals. The increase in DNA synthesis in the bone marrow of protected mice preceded the DNA content recovery. In the spleen and the thymus, no effect of liposomal MTP-PE was found.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed2004

Successful allogeneic bone marrow transplantation in a patient with acute myelogenous leukemia and cytomegalovirus retinitis.

A 1-year-old boy with acute myeloid leukemia with cytomegalovirus (CMV) retinitis that was refractory because of severely impaired cellular immunity underwent bone marrow transplantation from an HLA-matched donor after a conditioning regimen of busulfan, cyclophosphamide, and etoposide. Although we continued administration of ganciclovir from preparation therapy, retinitis worsened after engraftment. Thereafter retinitis improved gradually as the number of CD4+ T-lymphocytes increased. The findings in this case suggest that stem cell transplantation for a leukemia patient with CMV disease may be effective.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1980

Osmotic properties of a proliferating and differentiating line of cells from the bone marrow of the rat.

The effects of cellular differentiation on the osmotic properties of a proliferating line of bone marrow cells has been investigated. This population proliferated and differentiated into distinct maturation phases which have been separated quantitatively by velocity sedimentation at 1g in a Ficoll gradient. Certain osmotic characteristics were evaluated. The volume of osmotically active water increased linearly with maturation. The osmotically inactive volume was variable during proliferation and maturation. Several correlations that concerned the exosmotic movement of water were noted, as follows: 1) membrane permeability to water increased with an increase in the diameter of the nucleus, 2) the ratio of osmotically active water to mean corpuscular volume increased with an increase in the diameter of the nucleus, 3) membrane permeability to water increased with an increase in the osmotically active water normalized to the mean cell volume, and 4) the heat of activation associated with the permeability of the membrane to water increased during maturation and varied inversely with the ratio b/MCV. These results were used to assess the effects of cellular maturation on membrane function and the state of water in a maturing cell population. The permeability data suggest that charged groups on membrane proteins and phospholipids can vary the state of water in the membrane from a thermodynamically mobile state to an "ice-like" state. These unusual properties may be a direct result of a dynamic and functional relationship between cellular water and active biological macromolecules.

Animals↗
PubMed1987

Long-term effects of low-level 239Pu contamination on murine bone-marrow stem cells and their progeny.

The effects of long-term internal contamination with 13.3 kBq kg-1 239Pu injected intravenously were studied in 10-week-old ICR (SPF) female mice. Radiosensitivity of spleen colony-forming units (CFU-S) and 125IUdR incorporating into proliferating cells of vertebral bone marrow and spleens were determined in plutonium-treated and control animals one year after nuclide injection. The CFU-S in 239Pu-treated mice were more sensitive to X-rays (D0 = 0.52 +/- 0.01 Gy) than in controls (D0 = 0.84 +/- 0.02 Gy). 125IUdR incorporation into bone marrow and spleen cells was reduced after plutonium contamination. At one year following plutonium injection, the occurrence of chromosome aberrations was evaluated in metaphase figures of femoral bone marrow cells. The frequency of aberrations increased early after plutonium treatment, at later intervals it tended to decrease but not below the control level. While the relative numbers of vertebral marrow CFU-S decreased significantly, but only to 86 per cent of normal, cellularity of vertebral bone marrow, peripheral blood counts and survival of 239Pu-treated mice did not differ from the control data.

Alpha Particles↗
PubMed1996

Effects of vitamin B12 on cell proliferation and cellular alkaline phosphatase activity in human bone marrow stromal osteoprogenitor cells and UMR106 osteoblastic cells.

Pernicious anemia has recently been recognized as one of the risk factors for osteoporosis and bone fractures, but the underlying pathophysiologic mechanism is still unknown. To determine whether vitamin B12 has any direct effect on osteoblasts, we studied the effects of vitamin B12 on the proliferation and alkaline phosphatase activity in human bone marrow stromal osteoprogenitor cells (hBMSC) and UMR106 osteoblastic cells. Vitamin B12 at concentrations as low as 10(-12) mol/L significantly stimulated [3H]-thymidine incorporation in both types of cells, but concentrations higher than 10(-12) mol/L did not produce a greater effect. Vitamin B12 in the concentration range from 10(-12) to 10(-8) mol/L concentration-dependently increased alkaline phosphatase activity in both hBMSC and UMR106 cells. Based on these results, we suggest that a suppressed activity of osteoblasts may contribute to osteoporosis and fractures in patients with vitamin B12 deficiency.

Alkaline Phosphatase↗
PubMed2004

[Cellular aspects of bone regeneration: role of bone marrow periostium].

Bone regeneration is only possible if stem cells give rise to progenitors of osteoblasts, chondroblasts or chondroidocytes. Stem cells and osteogenic progenitors were evidenced in bone marrow while only progenitors can be found in periosteum. Bone marrow stem cells did show an amazing plasticity and some cells of the bone surrounding tissues such as perivascular cells, adipocytes, muscle cells or even circulating cells are able to transdifferentiate in osteoblasts when submitted to an osteogenic environment. We have shown that the destruction of both bone marrow and periost impairs the bone healing. It indicates that the periost and bone marrow destruction removes the predetermined osteogenic cells and the informative factors able to induce the transdifferenciation of the cells contained in the peri-osseous tissues.

Bone Marrow↗
PubMed1975

The cellular changes during osteogenesis in bone and bone marrow composite autografts.

Osteogenesis in and around autografts has been studied in the hope of identifying the osteoblast precursor. Fresh autografts of cortical bone with its constituent bone marrow were implanted into intramuscular sites in rats. The grafts were removed at intervals over a four week period and examined by light and electron microscopy. A chronological sequence of degenerative, reparative and differentiative events was found and described. The relative contributions of the host and graft components to post-grafting osteogenesis are discussed and the problem of the origin of the osteoblast cells is examined, taking into account present views about the interrelationships between skeletal connective tissue cells and their precursors. It is concluded that, in the investigation described, the presence of host granulation tissue was necessary for osteogenesis and it is postulated that osteoblast progenitor cells can arise from this granulation tissue, their differentiation along the osteogenic line being stimulated in some way by the presence of the graft bone.

Animals↗
PubMed2002

Human bone marrow stromal cells suppress T-lymphocyte proliferation induced by cellular or nonspecific mitogenic stimuli.

CD2(+) T lymphocytes obtained from either the donor of bone marrow stromal cells (BMSCs) or a third party were cultured in mixed lymphocyte reactions (MLRs) with either allogeneic dendritic cells (DCs) or peripheral blood lymphocytes (PBLs). When autologous or allogeneic BMSCs were added back to T cells stimulated by DCs or PBLs, a significant and dose-dependent reduction of T-cell proliferation, ranging from 60% +/- 5% to 98% +/- 1%, was evident. Similarly, addition of BMSCs to T cells stimulated by polyclonal activators resulted in a 65% +/- 5% (P =.0001) suppression of proliferation. BMSC- induced T-cell suppression was still evident when BMSCs were added in culture as late as 5 days after starting of MLRs. BMSC-inhibited T lymphocytes were not apoptotic and efficiently proliferated on restimulation. BMSCs significantly suppressed both CD4(+) and CD8(+) T cells (65% +/- 5%, [P =.0005] and 75% +/- 15% [P =.0005], respectively). Transwell experiments, in which cell-cell contact between BMSCs and effector cells was prevented, resulted in a significant inhibition of T-lymphocyte proliferation, suggesting that soluble factors were involved in this phenomenon. By using neutralizing monoclonal antibodies, transforming growth factor beta1 and hepatocyte growth factor were identified as the mediators of BMSC effects. In conclusion, our data demonstrate that (1) autologous or allogeneic BMSCs strongly suppress T-lymphocyte proliferation, (2) this phenomenon that is triggered by both cellular as well as nonspecific mitogenic stimuli has no immunologic restriction, and (3) T-cell inhibition is not due to induction of apoptosis and is likely due to the production of soluble factors.

Antibodies, Monoclonal↗