Isoforms of an endogenous lectin in rabbit bone marrow

A lectin which may mediate inter-erythroblast associations during red blood cell development in rabbit bone marrow has previously been purified and characterised. We have now detected different forms of this lectin in purified preparations and crude tissue extracts, by isoelectric focusing in agarose gels followed by rocket immunoelectrophoresis and by indirect antibody staining of focused proteins blotted onto nitrocellulose paper. These minor antigens are probably isoforms of the bone marrow lectin previously characterised.     

Stromal cells of the bone marrow in growing bone

By means of electron microscopy, cytochemistry and radioautography with 3H-thymidine, the bone marrow stromal cells have been studied in the zones of endochondral osteogenesis in the rabbit and rat femoral bones. In the stromal cells demonstrating a high alkaline phosphatase activity are distinguished: perivascular, reticular fibroblastic, osteogenic cells. Populations of the perivascular phosphatase-positive cells include poorly differentiated DNA-synthesizing forms, as well as cells with signs of differentiation into stromal fibroblasts. Cleft-like spaces in cytoplasm of the fibroblastic reticular cells are, probably, formed as a result of lymphocyte-like mononuclears passing through. Phagocyting stromal elements are presented by macrophages, having perivascular localization and including into composition of erythroblastic islets. Mononuclear macrophages are revealed also on the surface of osseous trabecules, where they participate in destruction of hemopoetic and osteogenic cells.     

Regulating effect of bone marrow cells on human T-lymphocyte function

A study was made of the regulatory effect of human bone marrow cells in two experimental systems: lymphocyte proliferation in response to PHA, and spontaneous and PHA-induced production of macrophage migration inhibition factor (MIF) by peripheral blood lymphocytes. It was shown that bone marrow cells inhibit the proliferative activity of stimulated peripheral blood lymphocytes and induced MIF production. The effect of bone marrow cells on spontaneous MIF production was found to be inconclusive.     

The effect of bleomycin on rat bone marrow cells.

Experiments were carried out to determine the cytogenetic effects of the antibiotic bleomycin (BLM) in rats using the bone marrow system. A total of eighteen male and eighteen female Sprague-Dawley rats were injected with varying concentration of BLM, over varying periods of time. The results revealed that at low concentrations BLM showed no alteration in the ploidy or the morphology of rat chromosomes. This however, was not the case when the dose or administration period was increased.     

Surface localization of an endogenous lectin in rabbit bone marrow

Summary A lectin, which may be involved in cell to cell adhesion during erythropoiesis in rabbit bone marrow, has been isolated and characterized. Several electron microscopical techniques have been used to investigate the cell surface distribution of this lectin in bone marrow utilizing colloidal gold conjugates of anti-lectin IgG or protein A. The lectin is present at the surface of erythroid cells at all stages of development but no lectin was detected on the surface of myeloid cells. The limitations and complementary nature of the techniques used are discussed.     

Inhibitory effect of NPY on isoprenaline-induced osteoclastogenesis in mouse bone marrow cells

The effect of neuropeptide Y (NPY), a co-transmitter with noradrenaline in peripheral sympathetic nerve fibers, on the osteoclastogenesis in mouse bone marrow cell cultures treated with isoprenaline, a beta-adrenergic receptor (beta-AR) agonist, was examined. The mouse bone marrow cells constitutively expressed mRNAs for the NPY-Y1 receptor and beta2-AR. NPY inhibited the formation of osteoclast-like cells induced by isoprenaline but not that by 1alpha,25-dihydroxyvitamin D3 (1alpha,25(OH)2D3) or soluble receptor activator of nuclear factor-kappaB ligand (RANKL); and it suppressed the production of RANKL and cyclic AMP (cAMP) increased by isoprenaline but not those increased by 1alpha,25(OH)2D3. NPY also inhibited osteoclastogenesis induced by forskolin, an activator of adenylate cyclase; however, it did not inhibit that induced by exogenously supplied dibutyryl cAMP, a cell-permeable cAMP analog that activates cAMP-dependent protein kinase. These results demonstrate that NPY inhibited the isoprenaline-induced osteoclastogenesis by blocking the agonist-elicited increases in the production of cAMP and RANKL in mouse bone marrow cells, suggesting an interaction between NPY and beta-AR agonist in bone resorption.     

Modifying effect of iron on lead-induced clastogenicity in mouse bone marrow cells

Essential trace elements such as iron (Fe) are known to interact with nonessential metals like lead (Pb), influencing its metabolism. Ferric chloride and lead nitrate were administered intraperitoneally to Swiss albino miceMus musculus singly and successively, with or without a time gap of 1 h, to study the degree of protection, if any, afforded by iron against the clastogenic effects induced by Pb in bone marrow cells. A decrease in the frequency of lead-induced chromosomal aberrations was observed when Fe was given together with or prior to Pb administration.     

Ultrastructure of reticulum cells in the bone marrow

In this study the attempt was made to classify the reticulum cells of the bone marrow on the basis of electron-microscopic findings. The basis of the differentiation was the ability of the cells to phagocytize substances or not. For two cell types the intracytoplasmic filaments were used as distinctive marks. The following classification resulted: (a) phagocytic reticulum cells, (b) undifferentiated reticulum cells, (c) fibrous reticulum cells of type I, which contain filaments of 4-8 nm diameter and are located near the blood sinus of the bone marrow, (d) fibrous reticulum cells of type II, which contain intracytoplasmic filaments of 10 nm diameter; since these cells contain neutral fat bodies, the possibility of a reversible conversion to fat cells has to be assumed and (e) fibroblasts, cells which synthesize the substance of the extracellular space. A connection of reticulum cells to haematopoietic functions or to stem cell functions could be found.     

The significance of the cellular factor in realizing the restorative effect of the procedure of bone marrow exfusion, incubation and reimplantation in irradiated mice

In experiments with F1 (CBA X C57Bl) mice irradiated with doses of 6.5 to 8.5 Gy the evidence was obtained for the important role of the reimplanted cells in a complete realization of the reparative effect of exfusion, incubation and reimplantation of bone marrow. The increase in radiation dose was accompanied by a tendency towards the decrease in the efficacy of the procedure, and, perhaps, by changes in the ratio of roots of haemopoietic stem cell differentiation.     

Endosteal cells of the bone marrow stroma in human iliac bone

The data on histological and electron microscopical investigation of the endosteal cells of the human iliac bone are presented. Three types of stromal elements in the endosteum, differing in their ultrastructural organization have been revealed. In the endosteal areas young hemopoietic cells are present, they are closely connected with the stroma. A suggestion is made on an important role of the endosteum in processes of proliferation and differentiation of hemopoietic predecessors.     

Hexokinase in bone marrow cells in the rabbit

The hexokinase isozymic pattern of circulating reticulocytes fractionated by density gradient ultracentrifugation was studied. All the cellular fractions obtained show similar ratio of hexokinase Ia/hexokinase Ib while a four fold decay in specific activity was evidenced. Bone-marrow cells of anemic rabbits also contain low amounts of HK Ib while this isozymic form is not present in basophilic erythroblasts.     

Osteogenic stem cells of the bone marrow

This paper presents literature and author's own data demonstrating that bone marrow contains determined osteogenic precursor cells with high potential to differentiation. They are stem cells of the bone and belong to the stromal cell line of the bone marrow which is histogenetically independent of hemopoietic cells. The paper presents detailed analysis of bone marrow stromal cells (CFUf) as well as of their osteogenic properties and requirements in growth factors. In conclusion mutual growth-stimulating interactions in the system of hemopoietic stromal cells are reviewed.     

The effect of serotonin on the hematopoietic stem cells of the bone marrow]

Haemopoietic stem cells content and proliferative activity were studied in the bone marrow of female F1 (CBA x C57Bl6) mice after single (50 mg/kg) and chronic (0.5 mg/kg daily for 7 days) serotonin (S) injections. It is shown that 9-day and 12-day COEs contents in the bone marrow of experimental mice has been increasing for 24 h after single S injection. After chronic S injections twofold increase of 12-day COEs is observed without any increasing of 9-day COEs. Total myelokaryocyte number is increased too. The study of proliferative status by in vitro incubation of bone marrow cells with ARA-C has shown that the numbers of 9-day and 12-day COEs in S-phase have increased both after single and chronic S injections. Possible mechanisms of stimulating effect of S on bone marrow stem cells are discussed.     

Effect of low oxygen tension on the biological characteristics of human bone marrow mesenchymal stem cells

Culture of mesenchymal stem cells (MSCs) under ambient conditions does not replicate the low oxygen environment of normal physiological or pathological states and can result in cellular impairment during culture. To overcome these limitations, we explored the effect of hypoxia (1 % O₂) on the biological characteristics of MSCs over the course of different culture periods. The following biological characteristics were examined in human bone marrow-derived MSCs cultured under hypoxia for 8 weeks: proliferation rate, morphology, cell size, senescence, immunophenotypic characteristics, and the expression levels of stemness-associated factors and cytokine and chemokine genes. MSCs cultured under hypoxia for approximately 2 weeks showed increased proliferation and viability. During long-term culture, hypoxia delayed phenotypic changes in MSCs, such as increased cell volume, altered morphology, and the expression of senescence-associated-β-gal, without altering their characteristic immunophenotypic characteristics. Furthermore, hypoxia increased the expression of stemness and chemokine-related genes, including OCT4 and CXCR7, and did not decrease the expression of KLF4, C-MYC, CCL2, CXCL9, CXCL10, and CXCR4 compared with levels in cells cultured under normoxia. In conclusion, low oxygen tension improved the biological characteristics of MSCs during ex vivo expansion. These data suggest that hypoxic culture could be a useful method for increasing the efficacy of MSC cell therapies.     

Decreasing endogenous glucocorticoids alters the ability of bone marrow cells to produce nitric oxide in response to stimulating agents

Glucocorticoids (GC) are essential for the body to maintain homeostasis. Patients with adrenal insufficiencies suffer from numerous health related problems including increased mortality due to sepsis. Here, we examine bone marrow (BM) cells from mice with adrenal insufficiency for their ability to produce nitric oxide (NO). Mice were injected with metyrapone (MR), an agent that selectively blocks glucocorticoid synthesis. BM cells were removed and tested for NO production. The stimulating agents LPS, TNF-alpha, IL-1beta, and IL-4 were all able to synergize with IFN-gamma, stimulating large concentrations of NO compared to normal mice. An important finding is that BM from injected mice produces NO in response to LPS alone, while normal BM cells do not. Experiments with anti IFN-gamma antibody demonstrate that, in MR injected mice, LPS alone stimulated sufficient quantities of IFN-gamma necessary for NO production. Our results demonstrate that reducing GCs alters regulation of NO production by BM cells at several levels.