Mercury and the activity of erythrocyte and bone marrow glutathione reductase (E.C. 1.6.4.2.) and glucose-6-phosphate dehydrogenase (E.C. 1.1.1.49) in rats

These studies were carried out on male Wistar rats. Erythrocyte and bone marrow activity of glutathione reductase (GR - E.C. 1.6.4.2) and glucose-6-phosphate dehydrogenase (G6PD - E.C. 1.1.1.49) were determined as affected by mercury. Under physiological conditions the above enzymes were found to be markedly more active in the bone marrow than in erythrocytes. The present experiments have revealed that within the first days there will be an increase in enzyme activity in the bone marrow as well as in glutathione reductase in erythrocytes. Simultaneously, a decline in the activity of erythrocytes could be observed which began within the very first days of the experiments as well as a decrease in the bone marrow, which occurred later in the course of the experiment.     

Erythropoietic bone marrow in the pigeon: development of its distribution and volume during growth and pneumatization of bones

During postnatal development of the pigeon, a large portion of the skeleton becomes pneumatized, displacing the hemopoietic bone marrow. The consequences of pneumatization on distribution and quantity of bone marrow as well as the availability of other sites for hemopoiesis have been investigated. Hemopoietic marrow of differently aged pigeons divided into five groups from 1 week posthatching (p.h.) up to 6 months p.h. was labeled with Fe-59 and examined by serial whole-body sections. Autoradiography and morphometry as well as scintillation counts of single bones and organs were also carried out. No sign of a reactivation of embryonic sites of erythropoiesis was found. Bone marrow weight and its proportion of whole-body weight increased during the first 4 weeks p.h. from 0.54% to 2.44% and decreased in the following months to about 1.0%. The developing bone marrow showed a progressive distribution during the first months of life, eventually being distributed proportionally over the entire skeleton, except for the skull. At the age of 6 months p.h. bone marrow had been displaced, its volume decreasing in correlation to increasing pneumaticity and conversion to fatty marrow. This generates the characteristic pattern of bone marrow distribution in adult pigeons, which shows hemopoietic bone marrow in ulna, radius, femur, tibiotarsus, scapula, furcula, and the caudal vertebrae.     

Stimulator of proliferation of spleen colony-forming cells in acute sterile inflammation

The presence and activity of a spleen colony-forming cell (CFU-S) proliferation stimulator was investigated in rat bone marrow after induction of sterile inflammation. Wistar rats were treated intraperitoneally with two 15 ml injections of 3.5% polyvinylpyrrolidone (PVP) at 18 h intervals, and the presence of CFU-S proliferation stimulator determined in bone marrow 6, 20 and 24 h after the first injection. The marrow of these mice was used to condition medium which was then fractionated using Amicon Diaflo ultrafiltration membranes. The 30–50 kDa fraction, taken from 20 h post-PVP-bone marrow extract, was found to induce cycling of d8-CFU-S in normal mouse bone marrow. This activity was not related to the presence of interleukins-1, -2 or -6 like activities in the material tested. The results demonstrate the existence of CFU-S proliferation stimulator in the bone marrow of rats with sterile inflammation (i.e. in an in vivo tissue response to non-specific cell stimulation), similar to that originally described as a macrophage product in mouse bone marrow after treatment with a variety of cytotoxic agents.     

Murine cytomegalovirus infection can enhance hybrid resistance through modulation of host natural killer activity

Studies were undertaken to assess the effect of murine cytomegalovirus (MCMV) in two different models involving injection of parental cells into F1 hosts. In both of these systems, MCMV-induced enhancement of hybrid resistance was found. In the first model, parent-into-F1 graft-vs-host reaction, MCMV infection of (C57BL/6 x C3H)F1 (B6C3F1) hosts was found to prevent the GVHR normally induced by injection of B6 parental splenocytes into the F1 hosts. The second model involved injection of parental bone marrow into lethally irradiated B6C3F1 and (C57BL/6 x DBA/2)F1 (B6D2F1) hosts. These irradiated hosts are known to exhibit resistance to engraftment by parental C57BL/6 (B6) bone marrow. This resistance was found to be markedly enhanced by injection of the hosts with MCMV 3 days before irradiation and bone marrow injection. In contrast, engraftment into B6C3F1 hosts of syngeneic marrow, or bone marrow from the C3H parent, was not affected by MCMV infection. Engraftment of DBA/2 marrow into B6D2F1 hosts was reduced at lower doses of injected marrow, suggesting enhanced resistance against the minor Hh Ag Hh-DBA. To test whether the MCMV-induced enhancement of resistance was mediated by NK cells, splenic NK activity (YAC-1 killing) and frequency (NK1.1 staining) were assessed. Both parameters were found to be elevated at 3 days after MCMV infection but to return to normal levels by 9 days. B6 bone marrow engraftment was in fact found to be normal when the marrow was administered to F1 mice 9 days after MCMV infection. Furthermore, anti-asialoGM1 administration prevented MCMV-induced enhancement of resistance to marrow engraftment. Thus, the NK enhancement resulting from MCMV infection appears to play a major role in the enhanced HR observed in the marrow engraftment model. This effect may be of importance in clinical bone marrow transplantation, a situation in which patients are susceptible to viral infection.     

Allogeneic bone marrow transplantation in conventional mice: I. Effect of antibiotic therapy on long term survival of allogeneic chimeras.

In the present communication the beneficial effect of long term antimicrobial treatment with poorly absorbable antiboitics on the survival of allogeneic bone marrow chimeras was investigated. The combination of C57Bl mice as bone marrow donors and CBA/CA mice as irradiated recipients (800 rad) was used because of their strong histoincompatibility on the H-2 loci. All allografted recipients received 10 X 10(6) bone marrow cells. The majority of the recipients, which were rendered gnotobiotic by an antimicrobial treatment, achieved stable long term chimerism. In contrast, the conventional chimeras died from secondary disease within 9 weeks after transplantation. As early as 14 days after allogeneic bone marrow grafting the gnotobiotic recipients tolerated the reassociation with a conventional microflora without a change in the rate of mortality. Bone marrow cells (8 X 10(6) i.v.) and spleen cells (2 X 10(6) i.v.) collected from allogeneic chimeras failed to induce graft-versus-host-reaction (GVH) in a second lethally irradiated host. The data indicate, that the high rate of mortality in murine allogeneic bone marrow chimeras results from delayed GVH-reaction and systemic infection. The marrow graft, once established seems to exert tolerance against the allogeneic host. The pathogenesis of the systemic infection has not yet been worked out. It is assumed that it originates from bacteremia, induced by radiation dependent lesions of the epithelial integrity and defected lymphatic tissue in the gut.     

Decrease of mutagenic action of cyclophosphamide by buckwheat melanin preparation

Melanins are polyphenolic pigments of plants, animals and microbes with antioxidant and antiradiation activity. Water-soluble melanin from buckwheat is experienced as antimutagenic means (0.01-10 mg/kg per os) for cyclophosphamide (20 mg/kg i.p.) in the 3 series of experiments. The frequency of chromosome aberrations in the cells of mice bone marrow after mutagene is reduced 2-6 times once under influence of melanin.     

Alkaline and acid phosphatase activity in murine femoral bone marrow following X-irradiation, or X-irradiation and repopulation with syngenic or allogeneic bone marrow or marrow stroma cells

The activity of alkaline and acid phosphatases in the bone marrow from the femoral cavity was investigated in the following groups of mice: (1) normal (non-irradiated); (2) irradiated with 600 R; (3) irradiated and repopulated with syngeneic bone marrow; (4) irradiated and repopulated with syngeneic marrow stroma; (5) non-irradiated, infused with allogeneic bone marrow (host versus graft reaction, HvG); (6) irradiated and repopulated with allogeneic bone marrow (graft versus host reaction, GvH). In addition, the activity of alkaline and acid phosphatases was examined in bone marrow stromal cultures. In irradiated animals the activity of both enzymes was lower than in non-irradiated ones, repopulation with syngeneic bone marrow restoring it to normal. Repopulation with allogeneic marrow (GvH) resulted in a very deep reduction of alkaline, but not acid, phosphatase. It is postulated that the decrease in bone marrow alkaline phosphatase activity can be a sensitive test for the early GvH reaction, preceding such parameters as splenomegaly. Marrow stroma cultured in vitro also showed very low alkaline phosphatase activity.     

Immunochemical characterisation of megakaryocyte potentiator activity from mouse bone marrow

Megakaryocyte potentiator derived from mouse bone marrow has been shown to be immunologically similar to Interleukin-6 (IL-6). In this study the activity has been characterised by biochemical and immunochemical techniques. The activity is described as a O-linked glycosylated molecule with an apparent MW of 15 Kd and pl of the range pH 5.9–6.35. The data show that mouse bone marrow potentiator activity is a variant of IL-6 and with the potential to enhance megakaryocyte growth. © 1995 Wiley-Liss, Inc.     

Stimulation of suppressor cells in the bone marrow and spleens of high dose cyclophosphamide-treated C57Bl/6 mice

Systemic administration of a single dose (300 mg/kg) of cyclophosphamide (Cy) induced the appearance of a population of suppressor cells in the bone marrow and spleens of mice. Suppressor cells were assayed by their capacity to inhibit the concanavalin A (Con A) blastogenesis or the mixed-lymphocyte response of normal C57Bl/6 spleen cells. Cy-induced bone marrow (Cy-BM) suppressor cells were present as early as 4 days following Cy therapy and their activity gradually decreased over the next 2 weeks. Cy-induced splenic (Cy-Sp) suppressor cells were maximally present on Days 6 through 10 following Cy therapy. Studies were performed to characterize the suppressor cells of bone marrow obtained 4 days after Cy treatment and of normal bone marrow (N-BM). Some suppressor activity was present in normal bone marrow. N-BM suppressor cells resembled cells of the monocyte/macrophage lineage in that they were slightly adherent to Sephadex G-10, sensitive to L-leucine methyl ester (LME), and insensitive to treatment either with anti-T-cell antibody and complement or with anti-immunoglobulin antibody and complement. Their suppressive activity was abrogated by incubation with either indomethacin or catalase. Cy-BM suppressor cells were also resistant to treatment with anti-T-cell and anti-immunoglobulin antibody and complement but were not adherent to Sephadex G-10 and not sensitive to LME. Their suppressive activity was partially eliminated by indomethacin alone or in combination with catalase. We conclude that Cy chemotherapy induces the appearance of a population of immune suppressive cells and that these cells appear first in the bone marrow and subsequently in the spleen.     

Characterization of cytotoxic cells generated from in vitro cultures of murine bone marrow cells

Bone marrow cells cultured for 5-6 days generate cytotoxic activity against a number of natural killer (NK)-susceptible tumor cells. In this study, these bone marrow cytotoxic cells were compared to cells with NK activity obtained either from spleen cells activated in vitro with interferon (IFN-alpha/beta) or mitogen or from peritoneal exudate cells (PEC) obtained 4 days after bacillus Calmette-Guerin (BCG) infection. Splenic and PEC cytotoxic cells were shown to be Thy 1.2+, NK 1.1+, Asialo GM+1, Lyt 1.2-, Lyt 2.2-. In contrast, bone marrow cytotoxic cells were Thy 1.2+, NK 1.1-, Lyt 1.2-, Lyt 2.2- and expressed low levels of Asialo GM1 antigen (Asialo GM +/- 1). Precursor cells for bone marrow cytotoxic activity were shown to be Thy 1.2-, NK 1.1-, Lyt 1.2-, Lyt 2.2- but also expressed low levels of Asialo GM1 antigen (Asialo GM +/- 1). Cytotoxic activity for both bone marrow and spleen cells peaked in the low-density fractions of discontinuous Percoll density gradients. The cytotoxic activity of these bone marrow cells was augmented by pretreatment with IFN (-alpha/beta, -gamma) or soluble factors (IFN free) from activated EL-4 thymoma cells. Surprisingly, the ability of bone marrow cells to generate high levels of cytotoxic activity following in vitro culture appeared to be associated primarily with mice which were of the H-2b haplotype.     

Potentiation by caffeine of the frequencies of micronuclei induced by mitomycin C and cyclophosphamide in young mice

Employing the micronucleus test in mouse bone marrow and in fetal mouse liver, the possible clastogenicity of caffeine as well as its influence on MMC- and CP-induced micronucleus levels were studied. The treatment of male and female C57Bl or BDF1 (C57Bl x DBA2) mice with caffeine (1 or 3 x 50 mg/kg and 100 mg/kg, s.c.) had no clastogenic effect in mouse bone marrow or in the fetal livers and maternal bone marrow when pregnant mice were injected with caffeine on day 16-17 of gestation. MMC (2.0 mg/kg, i.p.) increased up to 10-30-fold the number of MNPCEs in bone marrow compared to a 3-7 fold elevation of MNPCEs in fetal liver. A similar effect was also established in pregnant mice treated with CP (30 mg/kg, i.p.). No significant sex differences in spontaneous and MMC- or CP-induced MNPCEs levels were established in C57Bl and BDF1 mice. However, a significantly higher spontaneous rate of MNPCEs as well as a better-expressed responsiveness to the clastogenic activity of MMC and CP were established in C57Bl compared to BDF1 mice. The pregnancy had no effect on MMC- or CP-induced clastogenicity although a tendency to a decreased sensitivity to the damaging activity of MMC seemed to be detected in pregnant C57Bl mice compared to virgin female animals. The combined treatment of mice with caffeine (3 x 100 mg/kg) and MMC or CP caused an up to 45-49% potentiation of clastogenesis in the bone marrow of male, female and pregnant female C57Bl and BDF1 mice but not in fetal mouse livers.     

Stimulator of proliferation of spleen colony-forming cells in T-cell deprived mice treated with cyclophosphamide or irradiation

A role for T-cells in the regulation of CFU-S proliferation was investigated by determining the presence and activity of CFU-S proliferation stimulator (CFU-S stimulator) in adult mouse bone marrow after irradiation or cyclophosphamide (Cy) treatment. CBA mice previously deprived of T-cells by thymectomy, irradiation and bone marrow reconstitution (TIR) were thereafter treated with 4.5 Gy irradiation or 200 mg/kg Cy. Regenerating bone marrow cells of TIR and corresponding control mice after irradiation or Cy treatment produced CFU-S stimulator. The dose dependent increase in cytosine arabinoside cell death of normal bone marrow day 8 CFU-S was found when both CFU-S stimulators obtained after irradiation of TIR or corresponding control animals were tested. CFU-S stimulator activity in the bone marrow of TIR-Cy treated mice was also detected, but the effect was not dose-dependent. This was not related to the presence of an inhibitor of CFU-S proliferation. It appears that the CFU-S stimulator activity is not related to IL-6, IL-1 or IL-2, or to an inhibitor of IL-6 or IL-1 activity. The results demonstrate the existence of CFU-S proliferation stimulator unrelated to the two major monokines in the bone marrow of immunosuppressed mice.     

Diminished genotoxicity of mitomycin C and farmorubicin included in polybutylcyanoacrylate nanoparticles.

The genotoxic effects of mitomycin C (MMC) and farmorubicin (FR) in a free form and included in polybutylcyanoacrylate nanoparticles (PBCN) were studied employing the Salmonella/microsome mutagenicity assay and the micronucleus test in mouse bone marrow as well as in mouse fetal liver. The data obtained clearly indicated that MMC (0.25-2.00 micrograms/plate) was a strong mutagen in S. typhimurium TA102, while the same concentrations of this compound in PBCN were ineffective in inducing his+ revertant mutations in bacterial cells. A similar total suppression of mutagenic activity of FR (1.0-20.0 micrograms/plate) was registered in S. typhimurium TA98 when the drug was included in PBCN. Furthermore, the incorporation of MMC (2.0 or 4.0 mg/kg, i.p.) into PBCN strongly diminished or even abolished its clastogenic activity in the bone marrow of virgin and pregnant mice as well as in mouse fetal liver, respectively. In addition, a lack of genotoxic effect of PBCN only was also established. The toxic activity of MMC in mouse bone marrow was significantly reduced or completely abolished after its inclusion in PBCN. A conclusion might be drawn that the genotoxic activity of some antitumor drugs might be markedly diminished or even abolished after their incorporation in PBCN.     

Two subpopulations of stem cells for T cell lineage

An assay system for the stem cell that colonizes the thymus and differentiates into T cells was developed, and by using this assay system the existence of two subpopulations of stem cells for T cell lineage was clarified. Part-body-shielded and 900-R-irradiated C57BL/6 (H-2b, Thy-1.2) recipient mice, which do not require the transfer of pluripotent stem cells for their survival, were transferred with cells from B10 X Thy-1.1 (H-2b, Thy-1.1) donor mice. The reconstitution of the recipient's thymus lymphocytes was accomplished by stem cells in the donor cells and those spared in the shielded portion of the recipient that competitively colonize the thymus. Thus, the stem cell activity of donor cells can be evaluated by determining the proportion of donor-type (Thy-1.1+) cells in the recipient's thymus. Bone marrow cells were the most potent source of stem cells, the generation of donor-derived T cells being observed in two out of 14 recipients transferred with as few as 1.5 X 10(4) cells. The stem cell activity of spleen cells was estimated to be about 1% of that of bone marrow cells, and no activity was found in thymus cells. By contrast, when the stem cell activity was compared between spleen and bone marrow cells of whole-body-irradiated (800 R) C57BL/6 mice reconstituted with B10 X Thy-1.1 bone marrow cells by assaying in part-body-shielded and irradiated C57BL/6 mice, the activity of these two organs showed quite a different time course of development. Spleen cells showed a markedly high level of activity 7 days after the reconstitution, followed by a decline, whereas the activity of bone marrow cells was very low on day 7 and increased crosswise. The results strongly suggest that the stem cells for T cell lineage in the bone marrow comprise at least two subpopulations, spleen-seeking and bone marrow-seeking cells. Such patterns of compartmentalization of stem cells in the spleen and bone marrow of irradiated recipients completely conform to the general scheme of the relationship between restricted stem cells and less mature stem cells, including pluripotent stem cells, which became evident in other systems such as in the differentiation of spleen colony-forming cells or of stem cells for B cell lineage.     

Effect of exposure to stress on the role of T- and B-lymphocytes in the response of the hematopoietic system

Cellular composition of the bone marrow, spleen and peripheral blood was studied after 6-hour immobilization on the back in experiments on 4 groups of (CBAxC57BL)F1 mice with varying degree of T lymphocyte deficiency (thymectomy, sham thymectomy, administration of antilymphocytic serum, B mice). The evidence obtained shows that the "lymphoid peak" recorded in the bone marrow during stress is likely to be formed at the expense of T and B lymphocyte migration from the peripheral lymphoid organs. The data have been also obtained, indicating that T lymphocytes migrating to the bone marrow during the first 6-9 hours after the exposure to stress may participate in granulocytopoiesis activation.     

The Effects of Radiation and Hindlimb Unloading on Rat Bone Marrow Progenitor Cells

Bone marrow cells of mesenchymal origin play an important role in adaptation of physiological systems to space flight. Hematopoiesis, immunity, and homeostasis of bone tissue depend on their functional activity. An investigation that was carried out in the framework of the Bion and Bion-M programs showed a decrease of the number of rat bone marrow hematopoietic progenitors and the inhibition of lympho- and erythropoiesis when the granulocyte-macrophage linage was activated. A negative influence on nonhematopoietic bone marrow cells was also revealed. The pathogenetic influence of radiation and microgravity on the bone marrow progenitor cells has remained unclear so far. The goal of this research was to study the effect of a 30-day unloading and 6 days of γ-irradiation on rat bone marrow progenitor cells. The study was conducted on male rats of four groups: vivarium control (VC), hindlimb unloading (HU), irradiation (IR), and combined action (HU + IR). The following parameters have been examined: the number of bone marrow mononuclear cells, proliferative activity of marrow mononuclear cells, immunophenotype, number of hematopoietic CFU and CFU-f, and differentiation potency of hematopoietic and stromal bone marrow precursors. It was found that the cellularity and proliferation activity of rat bone marrow cells did not change under simulation of space flight. The number of CFU-f was decreased. Irradiation was accompanied by an increase in the hematopoietic cell share among total bone marrow mononuclear cells, while their activity was attenuated. The osteopotential of the stromal precursors was unchanged. Adipogenic differentiation was stimulated with irradiation. The functional activity of bone marrow progenitor cells was restored after 2 weeks of recovery. Thus, 30-day simulation of space flight factors negatively affected the morphofunctional properties of rat bone marrow progenitor cells. These effects were reversible upon 2 weeks of recovery.     

The role of separate subpopulations of bone marrow elements in regulating the proliferation processes of hemopoietic and tumor cells]

The role of intercellular interactions in regulation of proliferation process in normal and tumor cells has been studied in experiments with mouse hybrids F1 (CBA X C57BL/6). The cytostatic activity to tumor cells has been shown to possess both adherent and nonadherent cells of bone marrow. The adherent cell-effectors inhibit, nonadherent ones stimulate the DNA synthesis in myelokaryocytes of normal bone marrow. During the activation of bone-marrow proliferation (under 10-hour immobilized stress) the cytostatic effect of nonadherent cells to tumor ones grows; the myelokaryocyte proliferation is stimulated on the 4th day after immobilized stress. The cytostatic activity of adherent cell-effectors remains to be low up to 7th day after immobilization. The maximum of depression in cytostatic function of the adherent elements coincides with the peak of bone marrow proliferation activity (6th day). The character of changes in cytostatic activity of adherent cells to tumor and nontumor ones is of the same type. The data obtained testify to the generality of regulation mechanisms in proliferation of tumor and normal cells.     

Disorders of bone marrow hematopoiesis long time after the action of cytostatic preparations]

We studied the condition of CBA mice bone marrow hemopoiesis and functional activity of adherent cells 6 months after a single treatment with vinblastine (VB), doxorubicin (DR) and cyclophosphamide (CP) in LD10 dose (6, 22 and 250 mg/kg, respectively). There was a long-term disorganization of bone marrow cell composition. The damage may be attributed to exhaustion of the pools of stem cells and changes in function of the cells formed by hemopoiesis induction microenvironment.     

In vivo effects of interleukin-17 on haematopoietic cells and cytokine release in normal mice

In order to gain more insight into mechanisms operating on the haematopoietic activity of the T-cell-derived cytokine, interleukin-17 (IL-17) and target cells that first respond to its action in vivo, the influence of a single intravenous injection of recombinant mouse IL-17 on bone marrow progenitors, further morphologically recognizable cells and peripheral blood cells was assessed in normal mice up to 72 h after treatment. Simultaneously, the release of IL-6, IL-10, IGF-I, IFN-gamma and NO by bone marrow cells was determined. Results showed that, in bone marrow, IL-17 did not affect granulocyte-macrophage (CFU-GM) progenitors, but induced a persistant increase in the number of morphologically recognizable proliferative granulocytes (PG) up to 48 h after treatment. The number of immature erythroid (BFU-E) progenitors was increased at 48 h, while the number of mature erythroid (CFU-E) progenitors was decreased up to 48 h. In peripheral blood, white blood cells were increased 6 h after treatment, mainly because of the increase in the number of lymphocytes. IL-17 also increased IL-6 release and NO production 6 h after administration. Additional in vitro assessment on bone marrow highly enriched Lin- progenitor cells, demonstrated a slightly enhancing effect of IL-17 on CFU-GM and no influence on BFU-E, suggesting the importance of bone marrow accessory cells and secondary induced cytokines for IL-17 mediated effects on progenitor cells. Taken together, these results demonstrate that in vivo IL-17 affects both granulocytic and erythroid lineages, with more mature haematopoietic progenitors responding first to its action. The opposite effects exerted on PG and CFU-E found at the same time indicate that IL-17, as a component of a regulatory network, is able to intervene in mechanisms that shift haematopoiesis from the erythroid to the granulocytic lineage.     

Functional characteristics of a Ficoll-separated mouse bone marrow cell population involved in skin allograft prolongation

Treatment of recipient mice with donor bone marrow cells and anti-lymphocyte serum (ALS) results in extensive skin graft prolongation beyond that achieved in animals given only ALS. In this study, B6AF1 recipient mice were grafted with C3H/He skin on day 0, treated with ALS on days -1 and +2 and infused on day +7 with donor strain (C3H/He) bone marrow cells. Extensive graft prolongation was achieved either with 25 X 10(6) whole bone marrow cells or with 1 X 10(6) lymphoid-like cells derived from donor marrow that sediment at a rate of 3 mm/hr in a 2 to 4% Ficoll gradient at unit gravity. These allograft-prolonging lymphoid-like cells appear not to be CFUs cells, have suppressive activity in in vitro MLC assays, and contain both nylon wool adherent and non-adherent cells. These studies thus show that allograft promoting cells can be isolated from bone marrow utilizing Ficoll gradients. Functional studies suggest that 3 mm/hr sedimenting donor bone marrow suppressor cells may be involved in the induction of allograft prolongation.