The effect of aluminium upon the activity of selected bone marrow enzymes in rats.

This study was carried out on male Wistar rats. The bone marrow activities of acetylcholinesterase (AchE-EC.3.1.1.7.), glutathione reductase (GR-EC.1.6.4.2.) and glucose-6-phosphate dehydrogenase (G6PD-EC.1.1.1.49.) were determined as affected by aluminium. The present experiments have revealed that within the first days there will be an increase in enzyme activity in the bone marrow. Simultaneously a decline in the activity of bone marrow could be observed which occurred later in the first course of the experiment.     

Effects of acetylphenylhydrazine (APHZ) on the stromal cells of the bone marrow in rats (in vitro)

The study has been carried out on Wistar rats. The animals were divided into two groups: the control rats received 0.9% saline solution intraperitoneally in there consecutive days. The experimental animals were administered 1% solution of acetylphenylhydrazine (APHZ) intraperitoneally also in three days. Prior to the experiments samples of blood have been collected from tail veins and reticulocyte counts made: the counts had also been determined before the culture of tissue was started. On the fifth day of the primary culture, the morphology and enzymatic activity of the stromal cells of the bone marrow were studied. The cells grown in vitro were cultured by the use of the Eagle's medium enriched with 20% calf serum and L-glutamate. The type of the cells, their number and rate of growth were noted. In the cells the activity of specific esterase as well as acid and alkaline phosphatase was determined. Statistically significant differences between the control and experimental animals were found both in the numbers of stromal cells and in the differences in score values of activity of particular enzymes in various types of cells.     

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.     

Effects of aluminium salts on bone marrow chromosomes in rats in vivo

Oral administration of aluminium sulphate to laboratory bred Rattus norvegicus for prolonged period induced dose dependent inhibition of dividing cells and an increase in chromosomal aberrations. The effect was not influenced by the duration of exposure. The toxicity of the two salts, aluminium sulphate and potassium aluminium sulphate, did not differ significantly at doses in which the metal contents were kept constant.     

The effect of colony stimulating factor on the synthesis of ribonucleic acid by mouse bone marrow cells in vitro.

The effect of granulocyte-macrophage colony stimulating factor (GM-CSF) on the synthesis of RNA in liquid cultures of mouse bone marrow, spleen, thymus, peritoneal, peripheral blood leukocytes and lymph node cells was investigated. GM-CSF appeared to stimulate RNA-synthesis in syngeneic bone marrow cells within ten minutes of adding it to the culture. In the presence of GM-CSF bone marrow cultures maintained their initial rate of RNA synthesis for approximately ten hours. GM-CSF had no apparent effect on the uptake of 3H-uridine into bone marrow cells. This stimulation was still observed in the presence of puromycin and cycloheximide, but was abrogated by actinomycin D. The magnitude of the stimulation was not affected by the density of cells between 1 and 20 x 10(6) cells/ml but was slightly smaller at 0.1 and 40 x 10(6) cells/ml. Increasing concentration of GM-CSF (up to 2 X 105 units per ml) led to increased stimulation of RNA synthesis in bone marrow cells, but a significant stimulation could be detected at concentrations as low as 800 units/ml. GM-CSF did not significantly stimulate RNA synthesis in spleen, thymus, mesenteric or subcutaneous lymph node cells. However a small stimulation was observed in peripheral blood leukocytes and peritoneal cells. Autoradiographic studies showed that GM-CSF stimulated RNA synthesis in blast cells, myelocytes, metamyelocytes and polymorphs. Nucleated erythroid cells showed no increased labeling with GM-CFS. Labeling in lymphoid-like cells was highly variable but the level of labeling did not appear to be influenced by GM-CSF.     

Mutagenic effect of cyclophosphan on bone marrow cells of irradiated rats]

The rate of chromosome aberrations in bone marrow cells of male rats was investigated in 24 hours after the cyclophosphan intraperitoneal injection (25 mg/kg). Cyclophosphan was given to rats exposed earlier (15 days, 1, 3, 4, 6 or 9 months before) to X- and gamma-irradiation (400 rads). It was found that preliminary irradiation led to the increase in the mutagenic effect of cyclophosphan as compared to that obtained for intact rats. This effect was demonstrated during 4 months after acute X-irradiation at a dose rate of 70 rads/min and during 1 month after chronic gamma-irradiation at a dose rate of 100 rads/day. Later the effect was shown to disappear in both cases. Chronic irradiation was found to be less efficient in the stimulation of chromosome damages caused by chemical mutagens. The increase of the mutagenic effect of cyclophosphan resulted in the increase of both the number of cells carrying chromosome breaks and the severity of a damage per cell. Different ways of the irradiation effect on the mutagenic action of chemicals are discussed.     

The effect of vitamin D3 metabolites on normal and leukemic bone marrow cells in vitro

We studied the effects of 1,25-dihydroxyvitamin D3 and other metabolites of vitamin D3 on the maturation in liquid culture and on colony formation in semisolid media of marrow and buffy coat cells from patients with myeloid leukemias and from normal individuals. After incubation with 1,25-dihydroxy-vitamin D3, a proportion of both normal and leukemic myeloid cells resembled cells of the monocyte-macrophage lineage; these cells expressed alpha-naphthylacetate esterase and were able to phagocytize and kill candida organisms. When granulocyte-macrophage progenitor cells (CFU-GM) were incubated with 1,25-dihydroxyvitamin D3, the number of monocyte-macrophage colonies was increased and the number of granulocyte colonies was reduced; megakaryocyte colony formation (CFU-Mk) was inhibited substantially; and there was no effect on erythroid (BFU-E) or multilineage (CFU-GEMM) progenitor cell colony formation. We propose that 1,25-dihydroxyvitamin D3 may induce cells that are normally committed to differentiate along the granulocytic pathways to differentiate instead along the monocyte-macrophage pathway. If these in vitro observations reflect the in vivo activity of 1,25-dihydroxyvitamin D3, it may be involved in the modulation of collagen deposits in the bone marrow.     

Glycosphingolipid biosynthesis through asialogangliosides in rat bone marrow cells

Glycolipid biosynthesis in rat bone marrow cells has been studied with reference to four kinds of glycosyltransferases catalyzing the transfer of N-acetylgalactosamine, galactose, N-acetylneuraminic acid, and fucose to each glycolipid acceptor. It was demonstrated that glycosyltransferase activities which synthesize galactosylglucosylceramide (CDH) from glucosylceramide (CMH), N-acetylgalactosaminylgalactosylglucosylceramide (GA2) from CDH, galactosyl-N-acetylgalactosaminylgalactosylglucosylceramide (GA1) from GA2 and N-acetylneuraminylgalactosyl-N-acetylgalactosaminylgalactosylglucosylceramide (Gm1b) from GA1 were all present in rat bone marrow cell homogenate. Fucosyltransferase activity catalyzing the transfer of fucose from GDP-fucose to GA1 was also recognized in the cell homogenate. Neutral glycolipid extracted from rat bone marrow cells was analyzed by thin layer chromatography and glycosidase treatments. The presence of glycolipids corresponding to GA2, GA1 and fucolipid was demonstrated. From these results, it was concluded that the biosynthesis of glycolipid through asialogangliosides is a major biosynthetic route in rat bone marrow cells.     

Liproprotein inhibitor of bone marrow cells in tumor-bearing rats.

The role of a plasma inhibitor of erythropoiesis is evaluated in rats with Walker-256 carcinoma (W-256). Plasma from tumor-bearing rats was treated by gel filtration chromatography (Sephadex G-150) and fractions were combined into four pools on the basis of mol. wt. Inhibitory activity was assayed by adding an aliquot of the plasma fractions to normal rat marrow cells which were cultured for 24 hr with and without erythropoietin. 59Fe-heme synthesis, [3H]thymidine DNA synthesis, and 14C-leucine protein synthesis were studied. The results indicated that cultures containing the high mol. wt. pool (greater than 400,000 daltons) had significantly decreased heme, DNA and protein synthesis. This inhibitor also diminished the response to erythropoietin in polycythemic mice. The lower mol. wt. pool stimulated heme synthesis in vitro. To identify the inhibitor further, plasma lipoprotein classes were isolated by density gradient ultracentrifugation. The very low density lipoprotein (VLDL) and chylomicron fractions markedly inhibited DNA, protein and heme synthesis. Low density and high density lipoprotein fractions were inactive. A lipoprotein inhibitor of erythropoiesis was also identified in cancerous ascitic fluid, and to a lesser degree, in normal rat plasma. We suggest that this VLDL inhibitor of marrow erythropoiesis is a contributing factor in the anaemia of cancer.     

The effect of epitestosterone on estrogen biosynthesis in vitro.

OBJECTIVE: The concentrations of epitestosterone in human serum correlates negatively with that of estradiol. The possible explanation of this relation was addressed, and the influence of epitestosterone on kinetics of estradiol formation in vitro was evaluated. METHODS: The concentration of epitestosterone was measured in serum of 54 men participating in a screening program for prostate disease. Epitestosterone inhibition of aromatase and 17beta-hydroxysteroid dehydrogenase activities was tested in vitro in the system consisting of human placental microsomes, NADPH or NAD and NADP respectively, and epitestosterone in increasing concentrations. Testosterone, androstenedione, estrone and 17beta-estradiol were utilized as substrates. RESULTS: A significant negative correlation between epitestosterone and estradiol levels in human male serum was found. No inhibition of aromatase activity was observed; however, inhibition of 17beta-hydroxysteroid dehydrogenase was found preferentially in the direction leading to oxidation of the C-17 hydroxy group. The inhibitory effect of epitestosterone was more pronounced with androgens as substrates. CONCLUSION: Epitestosterone could influence the formation of estradiol in vitro rather by inhibition of 17beta-hydroxysteroid dehydrogenase than by blocking aromatase activity.     

Length of cell cycle in vitro and sister-chromatid exchange (SCE) frequency in bone marrow cells from severely malnourished rats

Cell proliferation and SCE frequency were evaluated through differential staining of sister chromatids in cultured bone marrow cells from rats malnourished during the lactation period. Cell proliferation was studied in vitro in sequential analysis every 5 h in cultures from 20 to 40 h of incubation. Results show a longer generation cycle in malnourished rat cells, revealing a delay in cell proliferation. Cells of this group of animals showed a higher percentage of first-cycle metaphases and lacked third-cycle metaphases even after 40 h of culture. This shows that the damage caused to cells of undernourished organisms used in this experiment persists even when they are placed in a nutrient-rich medium. The SCE frequency did not show differences between malnourished rats and their controls.     

Stromal cells of the regenerating bone marrow in rats (an immunocytochemical electron microscopy study)

Process of the bone marrow regeneration has been studied after its removal out of the rat femoral bone cavity. The stage of stroma formation precedes hemopoiesis. The stromal cells during its reconstruction (the 4th-5th day after removal of the bone marrow) are analyzed by means of the indirect immune-peroxidase electron microscopical method with antiserum applied against insoluble antigens of the rat bone marrow cells. Most of the stromal cells do not fix the antiserum used, as do the hemopoietic cells, macrophages and preosteoclasts. Some part of the stromal cells (not more than 30%) demonstrate the immune-peroxidase label. The labelled stromal cells have some ultrastructural signs of poorly differentiated elements of fibroblastic and osteoblastic raws. In the regeneration area, there are non-labelled poorly differentiated cells, which do not differ, at the ultrastructural level, from labelled poorly differentiated stromal elements. Possible causes of the difference revealed among the poorly differentiated stromal cells concerning their fixing of the anti-bone-marrow antiserum are discussed.