Histamine production by alloantigen-activated mouse bone marrow cells

Histamine's contribution to the manifestations associated with graft-versus-host disease (GVHD) and/or hybrid resistance is unknown. Thus, we initiated studies to see whether or not mouse bone marrow cells could produce histamine upon alloantigen stimulation. Irradiated allogeneic spleen cells were shown to stimulate bone marrow cells to produce and secrete high levels of histamine. During 7 days of culture there was only a marginal increase in cell-associated histamine while the amount of histamine in the supernatant increased 10- to 20-fold. Optimal histamine production was dependent upon Lyt 1+2+ T cells resident in the bone marrow. Further, bone marrow cells from Nude mice failed to produce high levels of histamine following alloantigen stimulation. Soluble factors produced by alloantigen-stimulated bone marrow cells or by Con A-stimulated rat spleen cells induced high levels of histamine production in bone marrow cells in the absence of alloantigen. We suggest that histamine production by alloantigen-activated bone marrow cells may modulate immune functions following bone marrow transplantation.     

Chylomicron metabolism. Chylomicron uptake by bone marrow in different animal species

Previously it was shown in rabbits that 20-40% of the injected dose of chylomicrons was cleared from the plasma by perisinusoidal bone marrow macrophages. The present study was undertaken to determine whether the bone marrow of other species also cleared significant amounts of chylomicrons. Canine chylomicrons, labeled in vivo with [14C]cholesterol and [3H] retinol, were injected into marmosets (a small, New World primate), rats, guinea pigs, and dogs. Plasma clearance and tissue uptake of chylomicrons in these species were contrasted with results obtained in rabbits in parallel studies. The chylomicrons were cleared rapidly from the plasma in all animals; the plasma clearance of chylomicrons was faster in rats, guinea pigs, and dogs compared with their clearance from the plasma of rabbits and marmosets. The liver was a major site responsible for the uptake of these lipoproteins in all species. However, as in rabbits, the bone marrow of marmosets accounted for significant levels of chylomicron uptake. The uptake by the marmoset bone marrow ranged from one-fifth to one-half the levels seen in the liver. The marmoset bone marrow also took up chylomicron remnants. Perisinusoidal macrophages protruding through the endothelial cells into the marrow sinuses were responsible for the accumulation of the chylomicrons in the marmoset bone marrow, as determined by electron microscopy. In contrast to marmosets, chylomicron clearance by the bone marrow of rats, guinea pigs, and dogs was much less, and the spleen in rats and guinea pigs took up a large fraction of chylomicrons. The uptake of chylomicrons by the non-human primate (the marmoset), in association with the observation that triglyceride-rich lipoproteins accumulate in bone marrow macrophages in patients with type I, III, or V hyperlipoproteinemia, suggests that in humans the bone marrow may clear chylomicrons from the circulation. It is reasonable to speculate that chylomicrons have a role in the delivery of lipids to the bone marrow as a source of energy and for membrane biosynthesis or in the delivery of fat-soluble vitamins.     

Long-term immunologic induction of donor-specific tolerance to skin allografts by bone marrow transplant in rabbits

The induction of donor-specific tolerance to skin allografts was investigated in rabbits using bone marrow transplantation techniques reported to be effective in mice. Various routes of bone marrow transplantation (i.e., intravenous, portal venous, or intraosseous) were also examined. In regimen A, the animals were treated with portal venous injection of bone marrow cells from the donor on day 0 and intravenous injection of bone marrow cells from the same donor on posttransplant day 5. In regimen B, the animals were treated with portal venous and intraosseous injections of donor bone marrow cells on day 0 and intravenous injection of bone marrow cells from the same donor on posttransplant day 5. In regimen C, the animals were given intraosseous injection of donor bone marrow cells on day 0 and intravenous injection of bone marrow cells from the same donor on posttransplant day 5. It was found that regimens B and C were more effective than regimen A in prolonging allograft survival. The results demonstrate that induction of allograft tolerance can be achieved by bone marrow transplantation in a rabbit model. This protocol deserves further study in other large animal models.     

Suppression by bone marrow cells of the level of specific IgE antibodies in the blood of mice and decrease in the production of IGE by bone marrow cells

Changes in the level of the specific IgE-antibodies to ovalbumin under the influence of syngeneic cells of a bone marrow were studied. The IgE-response was induced by ovalbumin in mice (CBA X C57Bl/6)F1. The bone marrow cells suspensions (20-30 X 10(6) cells per mouse) from syngeneic donors was inoculated simultaneously with the immunization. It was found that bone marrow cells suppressed both the level of IgE-antibodies in experimental mice serum and the production of IgE by the bone marrow cells of the recipient. The ability to suppress IgE-response remained when erythrocytes, monocytes and T-lymphocytes were removed from inoculated suspensions. The bone marrow cells taken from the mice immunized with ovalbumin, at the stage of a decreasing IgE-response, provided more pronounced suppression, than bone marrow cells taken from intact animals.     

Differentiating Functional Roles of Gene Expression from Immune and Non-immune Cells in Mouse Colitis by Bone Marrow Transplantation

To understand the role of a gene in the development of colitis, we compared the responses of wild-type mice and gene-of-interest deficient knockout mice to colitis. If the gene-of-interest is expressed in both bone marrow derived cells and non-bone marrow derived cells of the host; however, it is possible to differentiate the role of a gene of interest in bone marrow derived cells and non- bone marrow derived cells by bone marrow transplantation technique. To change the bone marrow derived cell genotype of mice, the original bone marrow of recipient mice were destroyed by irradiation and then replaced by new donor bone marrow of different genotype. When wild-type mice donor bone marrow was transplanted to knockout mice, we could generate knockout mice with wild-type gene expression in bone marrow derived cells. Alternatively, when knockout mice donor bone marrow was transplanted to wild-type recipient mice, wild-type mice without gene-of-interest expressing from bone marrow derived cells were produced. However, bone marrow transplantation may not be 100% complete. Therefore, we utilized cluster of differentiation (CD) molecules (CD45.1 and CD45.2) as markers of donor and recipient cells to track the proportion of donor bone marrow derived cells in recipient mice and success of bone marrow transplantation. Wild-type mice with CD45.1 genotype and knockout mice with CD45.2 genotype were used. After irradiation of recipient mice, the donor bone marrow cells of different genotypes were infused into the recipient mice. When the new bone marrow regenerated to take over its immunity, the mice were challenged by chemical agent (dextran sodium sulfate, DSS 5%) to induce colitis. Here we also showed the method to induce colitis in mice and evaluate the role of the gene of interest expressed from bone-marrow derived cells. If the gene-of-interest from the bone derived cells plays an important role in the development of the disease (such as colitis), the phenotype of the recipient mice with bone marrow transplantation can be significantly altered. At the end of colitis experiments, the bone marrow derived cells in blood and bone marrow were labeled with antibodies against CD45.1 and CD45.2 and their quantitative ratio of existence could be used to evaluate the success of bone marrow transplantation by flow cytometry. Successful bone marrow transplantation should show a vast majority of donor genotype (in term of CD molecule marker) over recipient genotype in both the bone marrow and blood of recipient mice.     

T cell regulation of interferon-alpha/beta (IFN-alpha/beta) production by alloantigen-stimulated bone marrow cells

We have previously reported that mouse bone marrow cells produce high levels of interferon-alpha/beta (IFN-alpha/beta) after 5 to 6 days of in vitro culture with irradiated allogenic spleen cells. The current study was initiated to determine whether or not T cells are important for alloantigen-induced IFN-alpha/beta production by mouse bone marrow cells. Bone marrow cells and spleen cells were obtained from C57BL/6 mice. These cells were treated with different monoclonal antisera and complement, and then were cultured 5 to 6 days with irradiated DBA spleen cells. The results from these experiments indicated that optimal IFN-alpha/beta production by alloantigen-stimulated bone marrow cells required Lyt-1+2+ T cells. In addition, when bone marrow cells obtained from nu/nu B10 mice were cultured with alloantigen, only low levels of IFN were produced when compared with IFN production by bone marrow cells obtained from normal littermate B10 mice. The addition of nylon wool-enriched splenic T cells to cultures containing bone marrow cells and alloantigen resulted in an augmentation of IFN-alpha/beta production by three-fold to fivefold. Furthermore, bone marrow cells obtained from alloantigen-immunized mice produced much higher levels of IFN-alpha/beta and in a shorter period of time (2 to 3 days) when compared with bone marrow cells obtained from control or non-immunized mice. Cyclosporin A (CsA) has been shown to inhibit predominantly T cell-dependent responses. The effect of CsA on IFN production by alloantigen-stimulated bone marrow and spleen cells was investigated. The addition of CsA at concentrations as low as 0.1 micrograms/ml inhibited not only IFN-gamma production by alloantigen-stimulated spleen cells, but also IFN-alpha/beta production by alloantigen-stimulated bone marrow cells. In contrast, IFN-alpha/beta production by Newcastle disease virus-infected spleen cells, bone marrow cells, or L cells was not inhibited by the addition of CsA (1 microgram/ml). Thus, the ability of bone marrow cells to produce high levels of IFN-alpha/beta after in vitro culture with alloantigen is dependent upon T cells resident in the bone marrow. IFN-alpha/beta production by alloantigen-stimulated bone marrow cells may play a major role in the pathogenesis associated with graft-vs-host disease and in T cell regulation of hematopoiesis.     

Radiosensitivity of pluripotent stem cells detectable by cloning in the spleen of irradiated mice

It was shown that the dose--effect curves describing the radiosensitivity of CFUc of the bone marrow irradiated in vitro (0.04-3.7 Gy) and treated with normal rabbit serum (NRS) and anti-mouse-brain serum (AMBS) has two differently sloping portions indicating that two CFUc populations differing in radiosensitivity are present in the bone marrow. D0 was 0.93 Gy after irradiation with doses of 0.04-0.75 Gy and treatment with NRS, and 0.33 Gy after incubation of the bone marrow with AMBS. The addition of thymus cells "straightened" the dose--effect curve for the bone marrow treated with AMBS: in this case D0 was 1.81 Gy exceeding considerably the values of D0 for intact bone marrow. The CFUc population is suggested to be heterogeneous in radiosensitivity.     

Hematopoietic precursor cells in radiation chimeras restored by bone marrow from thymectomized mice]

Radioprotective capacity of bone marrow CFUs of adult thymectomized mice was studied. Lethally irradiated mice were inoculated with bone marrow of mice thymectomized 8-11 months before. The colony forming capacity and proliferative rate of CFUs were studied 1-7.5 months after obtaining the radiation chimeras. It has been shown that proliferative capacity of bone marrow of adult thymectomized mice was reduced in comparison with that of normal animals. It is related to the decrease (4-fold) of the proliferative rate of bone marrow of thymectomized mice which was inoculated into lethally irradiated recipients 1 month before. We also found that the content of CFUs in bone of those chimeras was reduced later--after 7.5 months. In this period (1-7.5 months) the cellularity of bone marrow did not change.     

Chylomicron-chylomicron remnant clearance by liver and bone marrow in rabbits. Factors that modify tissue-specific uptake

The metabolism of [14C]cholesterol- and [3H]retinol-labeled chylomicrons obtained from canine thoracic duct or rabbit mesenteric lymph was investigated in normal fasted rabbits. Typically, 70-80% of the chylomicrons injected into the rabbits were cleared from the plasma in 20 min, and their uptake was accounted for principally by the liver and the bone marrow. Surprisingly, the bone marrow was a major site of uptake; the uptake ranged from about half that of the liver to a nearly equal amount. The importance and specificity of chylomicron-chylomicron remnant uptake by the bone marrow were established by demonstrating that (a) bone marrow throughout the body accumulated these lipoproteins, (b) the level of uptake was consistent regardless of how the values were calculated or how the chylomicrons were prepared, (c) the uptake represented specific binding, and (d) radiolabeled intestinal lipoproteins induced in vivo delivered cholesterol and retinol to the marrow. Electron microscopic examination of the rabbit bone marrow established that perisinusoidal macrophages uniquely accounted for the uptake of the chylomicrons. Whereas liver cleared a variety of both triglyceride-rich lipoproteins (chylomicrons, chylomicron remnants, and very low density lipoproteins) and cholesterol-rich lipoproteins (beta-very low density lipoproteins and high density lipoproteins containing apolipoprotein E), bone marrow uptake appeared to be restricted to the triglyceride-rich lipoproteins. More chylomicron remnants (generated in a hepatectomized rabbit) were cleared by the liver than by the bone marrow, and the addition of excess apolipoprotein E to chylomicrons resulted in their preferential uptake by the liver. The role of chylomicron-chylomicron remnant delivery of lipids or lipid-soluble vitamins to rabbit bone marrow is open to speculation, and whether triglyceride-rich lipoprotein uptake occurs to a significant extent in the bone marrow of humans remains to be determined.     

Stimulation by normal and leukemic mouse sera of colony formation in vitro by mouse bone marrow cells

Using a modification of the agar gel method for bone marrow culture, serum from various strains of mice has been tested for colony stimulating activity. Ninety percent of sera from AKR mice with spontaneous or transplanted lymphoid leukemia and 40–50% of sera from normal or preleukemic AKR mice stimulated colony formation by C57B1 bone marrow cells. Sera from 6% of C3H and 30% of C57B1 mice stimulated similar colony formation. The incidence of sera with colony stimulating activity rose with increasing age. All colonies were initially mainly granulocytic in nature but later became pure populations of mononuclear cells. Bone marrow cells exhibited considerable variation in their responsiveness to stimulation by mouse serum. Increasing the serum dose increased the number and size of bone marrow cell colonies and with optimal serum doses, 1 in 1000 bone marrow cells formed a cell colony. Preincubation of cells with active serum did not stimulate colony formation by washed bone marrow cells. The active factor in serum was filterable, non-dialysable and heat and ether labile.     

Potentiation of bone marrow colony growth in vitro by the addition of lymphoid or bone marrow cells

Colony formation and growth in vitro by C57B1 mouse bone marrow cells were analysed following stimulation by a standard dose of serum colony stimulating factor. Under restricted conditions, colony crowding was observed to potentiate colony growth rates. The addition of thymic or lymph node lymphoid cells or nonviable bone marrow cells also potentiated colony growth. Extensive reutilisation of nuclear material by bone marrow colony cells was observed when labeled lymphoid and bone marrow cells were added to the culture system. The results provide evidence that lymphocytes can exert trephocytic effects on proliferating hematopoietic cells.     

Bone morphogenetic proteins inhibit adipocyte differentiation by bone marrow stromal cells

The bone morphogenetic proteins were originally identified based on their ability to induce ectopic bone formation in vivo and have since been identified as members of the transforming growth factor-β gene superfamily. It has been well established that the bone morphogenetic cytokines enhance osteogenic activity in bone marrow stromal cells in vitro. Recent reports have described how bone morphogenetic proteins inhibited myogenic differentiation of bone marrow stromal cells in vitro. In vivo, bone marrow stromal cells differentiate along the related adipogenic pathway with advancing age. The current work reports the inhibitory effects of the bone morphorphogenetic proteins on adipogenesis in a multipotent murine bone marrow stromal cell line, BMS2. When exposed to bone morphogenetic protein-2, the pre-adipocyte BMS2 cells exhibited the expected induction of the osteogenic-related enzyme, alkaline phosphatase. Following induction of the BMS2 cells with adipogenic agonists, adipocyte differentiation was assessed by morphologic, enzymatic, and mRNA markers. Flow cytometric analysis combined with staining by the lipophilic fluorescent dye, Nile red, was used to quantitate the extent of lipid accumulation within the BMS2 cells. By this morphologic criteria, the bone morphogenetic proteins inhibited adipogenesis at concentrations of 50 to 500 ng/ml. This correlated with decreased levels of adipocyte specific enzymes and mRNAs. The BMS2 pre-adipocytes constitutively expressed mRNA encoding bone morphogenetic protein-4 and this was inhibited by adipogenic agonists. Together, these findings demonstrate that bone morphogenetic proteins act as adipogenic antagonists. This supports the hypothesis that adipogenesis and osteogenesis in the bone marrow microenvironment are reciprocally regulated.     

Protection by protein A of apoptotic cell death caused by anti-AIDS drug zidovudine.

Zidovudine, the anti-AIDS drug, caused inhibition of mitogen-induced proliferation and perturbation of cell-cycle progression of cultured bone marrow cells of mice. There was significant hypoploidy observed in flow cytometric analysis of AZT-treated bone marrow cells. In apo-direct analysis, cells showed apoptosis in G0/G1 phase. In DNA gel analysis, characteristic laddering of apoptosis was observed in AZT-treated bone marrow cells. We demonstrated that, when the animals were pretreated with protein A (PA) of Staphylococcus aureus, the apoptotic changes could be prevented in bone marrow cells of AZT-treated animals. There is a significant (p < 0.05) increase in proliferation of bone marrow cells subjected to mitogen treatment in PA+AZT-treated animals, compared to only AZT-treated animals. However, cell-cycle phase distribution was not hampered and no laddering in DNA gel analysis was also observed in this group. In apo-direct analysis, PA treatment showed significant (p < 0.001) inhibition of AZT-induced apoptosis. These observations indicate that by using a suitable agent such as protein A the toxic side effects of AZT could be minimized.     

Separation of osteoblast-like cells from bone marrow by fluorescence-activated cell sorting

The purification of the osteoblast-like cells (2-3%) among the bone marrow cells (BMC) of C57BL/6 mice using a specific anti-osteoblast serum and a fluorescence-activated cell sorter is described. The antiserum was raised against osteoblast cells isolated from calvaria from neonatal mice. The majority of the cells of the osteoblast-enriched fraction from bone marrow showed a parathormone-induced increase in cyclic adenine monophosphate but no response to calcitonin. This is similar to the response of osteoblast cells obtained from the calvaria. Electron microscopic studies of the extracellular matrix of cultured osteoblast-like cells purified from bone marrow showed the deposition of apatite crystals within and in close apposition to the vesicles. These findings suggest that the isolated cell population was enriched in osteoblasts. Such a cell system from bone marrow might provide an experimental system for investigating the mechanism of bone formation.     

Identification of parathyroid hormone-regulated proteins in mouse bone marrow cells by proteomics

The ability of parathyroid hormone (PTH) to enhance bone formation has recently been exploited in the treatment of osteoporosis. Several studies have suggested that the activation of bone marrow stromal cells could be preceded to show the anabolic effect of PTH on bone formation, but little is known of PTH-regulated proteins in bone marrow cells. Therefore, protein profiling in the intermittent PTH-treated bone marrow cells was evaluated using proteomics. Daily treatment for 5 days consisting of subcutaneous injection of either 150 microg/kg per day of mouse PTH (1-84) or vehicle (0.9% normal saline) was performed on the ICR mouse. At the end of the treatment period, bone marrow cells were separated and used in proteomics. The expression levels of seven proteins including vimentin were decreased, but those of four proteins including calreticulin and thioredoxin domain containing 7 protein (Txnde7) were increased. Among these, the decrease of vimentin and the increase of both calreticulin Txnde7 in mRNA levels were confirmed by semi-quantitative RT-PCR. In PTH-treated mouse MC3T3-E1 osteoblast cells, mRNA expression levels were not totally consistent with the results observed in proteomics. In conclusion, the differentially expressed proteins in bone marrow cells depending on PTH could be highly linked to the differentiation of osteoprogenitor cells in the bone marrow into preosteoblast cells.     

Mechanisms underlying catabolic and anabolic functions of parathyroid hormone on bone by combination of culture systems of mouse cells

Since bone resorption and formation by continuous and intermittent parathyroid hormone (PTH) treatments involve various types of cells in bone, this study examined the underlying mechanism by combining culture systems using mouse primary calvarial osteoblasts and bone marrow cells. The PTH/PTHrP receptor (PTH1R) expression and the cAMP accumulation in response to PTH were increased in accordance with the differentiation of osteoblasts. Osteoclast formation was strongly induced by continuous PTH treatment in the monolayer co‐culture of osteoblasts and bone marrow cells, which was associated with RANKL expression in differentiated osteoblasts. Bone formation determined by ALP activity and the type I collagen mRNA expression was stimulated by intermittent PTH treatment in the monolayer co‐culture and in the bone marrow cell layer of the separated co‐culture in a double chamber dish, but not in the culture of bone marrow cells alone. The stimulation in the separated co‐culture, accompanied by IGF‐I production by osteoblasts, was abolished when bone marrow cells were derived from knockout mice of insulin‐receptor substrate‐1 (IRS‐1?/?) or when osteoblasts were from PTH1R?/? mice. We conclude that differentiated osteoblasts are most likely the direct target of both continuous and intermittent PTH, while bone marrow cells are likely the effector cells. The osteoblasts stimulated by continuous PTH express RANKL which causes osteoclastogenesis from the precursors in bone marrow via cell‐to‐cell contact, leading to bone resorption; while the osteoblasts stimulated by intermittent PTH secrete IGF‐I which activates IRS‐1 in osteoblast precursors in bone marrow via a paracrine mechanism, leading to bone formation. J. Cell. Biochem. 109: 755–763, 2010. © 2010 Wiley‐Liss, Inc.     

Augmentation of erythroid burst formation by the addition of thymocytes and other myelo-lymphoid cells

Bone marrow from barrier-sustained specific pathogen-free (SPF) CBA and C57BL/6 mice gave relatively low numbers of BFU-E colonies in methylcellulose culture, as compared to conventional mice. Addition of thymocytes to the marrow cultures increased the yield of BFU-E colonies more than fourfold in SPF mice but only 1.5-fold in conventional mice. Colony size was also increased. Increased yield of BFU-E colonies was also obtained by co-culture of bone marrow with lymph node cells or with bone marrow or spleen cells from 900R whole-body-irradiated mice. The effect appeared to be cellular rather than humoral. It was not reproduced by conditioned medium from thymus or pokeweed mitogen stimulated spleen cells. The helper effect of thymus cells was eliminated or reduced by freezing and thawing, or by 48 hours of incubation after irradiation. Treatment of bone marrow cells in vitro with anti-theta serum and complement did not decrease the number of BFU-E colonies. The putative helper cells appear not to be T cells, were non-adherent to the plastic culture dish, and were cortisone resistant and radioresistant. The low BFU-E colony yield from SPF mouse marrow is presumed to be largely the result of deficiency of these non-T helper cells in SPF bone marrow, rather than of BFU-E progenitor cells.     

Bone marrow cell differential counts obtained by multidimensional flow cytometry.

Five-dimensional flow cytometric analysis of normal bone marrow aspirates was utilized to determine the frequency of neutrophils, eosinophils, monocytes, lymphocytes, nucleated erythrocytes, reticulocytes, platelets, and a cell population that included blasts of each of the cell lineages, megakaryocytes, plasma cells, and basophils. Each of these bone marrow cell populations had unique features with respect to forward light scatter, orthogonal light scatter, and staining with Thiazole-Orange, LDS-751, and CD45 labeled with Phycoerythrin (PE). The identity of the cell populations was verified by sorting each of the cell populations and subsequent light microscopic examination of the cells. The frequencies of the nucleated bone marrow cell subpopulations of 50 normal donors were for neutrophils, mean 72.3%; SD +/- 5.1; 95% limits, 70.9-73.8%; eosinophils, mean 1.8%; SD +/- 1.3; 95% limits, 1.4-2.1%; monocytes, mean, 2.8%; SD +/- 1.2; 95% limits, 2.5-3.1%; lymphocytes, mean 12.1%; SD +/- 3.6; 95% limits 11.1-13.2%; nucleated erythrocytes, mean 8.9%; SD +/- 3.9; 95% limits, 7.8-10.1%; and the cell population that included blasts of each of the cell lineages, megakaryocytes, plasma cells, and basophils, mean 1.6%; SD +/- 1.2; 95% limits, 1.3-1.9%. The percentage of reticulocytes in bone marrow aspirates from 50 normal donors correlated with the reticulocyte frequency in the peripheral blood of these donors. However, the mean frequency of reticulocytes was significantly greater (p < 0.0001) in bone marrow (mean 2.19%; SD +/- 0.88) than in peripheral blood (mean 1.71%; SD +/- 0.88). The technique could discriminate between immature and mature reticulocytes based on the brighter staining with both Thiazole-Orange and LDS-751 of the immature reticulocytes. This was confirmed by cell sorting of both reticulocyte populations, which revealed larger clumps of New Methylene Blue staining material in the brighter Thiazole-Orange and LDS-751 stained reticulocytes. The immature reticulocytes were present in normal bone marrow, but not in normal peripheral blood. As expected, a significantly greater frequency of nucleated cells was found in bone marrow aspirates (mean 0.85%; SD +/- 0.59) than in peripheral blood (mean 0.20%; SD +/- 0.11). The frequency of platelets was significantly lower in bone marrow (mean 1.24%; SD +/- 0.69) than in peripheral blood (mean 2.94%, SD +/- 1.14). Flow cytometric bone marrow analysis can provide clinical laboratories with a technique that generates quantitative bone marrow cell differentials and potentially can reduce the need for light microscopic examination of bone marrow smears.     

Detection of bone marrow-derived cells in neointimal thickening in the rat carotid artery by nested polymerase chain reaction

The bone marrow origin of cells involved in neointimal formation after injury of the luminal surface of the vessel was confirmed by highly sensitive nested polymerase chain reaction on isolated vascular wall cells. The model of intimal hyperplasia after balloon angioplasty of the carotid artery in radiation bone marrow chimeras between male and female Wistar rats was used. The Y chromosomes of rat male donors of the bone marrow for irradiated females were used as a marker of bone marrow-derived cells. This approach demonstrated a bone marrow origin of a large fraction of α-actin-positive (smooth muscle) neointimal cells.     

Correction of a T-immunodeficit in mice by bone marrow transplantation from donors treated with hydrocortisone]

Adult CBA mice were exposed to thymectomy, lethal irradiation, and protection by syngeneic bone marrow transplantation. In some experiments syngeneic bone marrow of donors, treated with hydrocortisone in a dose of 125 mg/kg for 3 days was used. The bone marrow of these donors contained cells with the Q-marker. Thymectomized and lethally irradiated animals subjected to the transplantation of syngeneic bone marrow from hydrocortisone-treated donors rejected the skin allotransplants, and the lymph node cells of these mice suppressed the endogenous colony-formation in the sublethally-irradiated hybrids (CBA X C57Bl/6) F1.