The structural-functional organization of the bone marrow after lethal irradiation and the transplantation of syngeneic hematopoietic cells]

A study was made of the content and morphology of haemopoietic islands in the bone marrow of lethally irradiated CBA mice, and their change after transplantation of syngeneic haemopoietic cells. The data obtained show that the haemopoietic islands are reconstructed in the injured haemopoietic tissue due to the donor's bone-marrow nuclears. A new type of structural and functional associations, namely, stromal haemopoietic islands, has been found.     

The structural-functional organization of the auditory cortex in rats]

Using axonal transport of horseradish peroxidase and electrophysiological mapping technique, studies have been made on structural and functional organization of the auditory cortex in rats. After the injection of HRP to peripheral parts of the auditory cortex, mainly initial neurones were found in the dorsal and median parts of the geniculate body. Electrophysiological experiments revealed the localization of neurones with widespread frequency-threshold curves and high thresholds at characteristic frequency. On the basis of the data obtained, it is suggested that similar to other mammals, rats have the areas of secondary fields of the auditory cortex which surround central coniocortex.     

Cytogenetic changes in the bone marrow cells of long-term irradiated rats]

The occurrence and characteristics of the chromosome structural changes in femur bone marrow cells under continuous irradiation with the exposure rate of 50 R/day within 90 days was followed. The 25% increase in the chromosome aberration frequency was observed within 7 days of the irradiation, and then the aberration rate was constant up to the end of the irradiation (90 days).     

Analysis of chromosome aberrations in bone marrow cells of rats after treatment with isoniazid

Summary 100 mg INH/kg body weight was administered to male Wistar rats five times, at 24 h intervals, either intraperitoneally or intravenously. In both experimental series the yield of chromosome aberrations in bone marrow cells was not increased as compared to controls.     

Effect of stimulating antibody formation under the influence of bone marrow cells in vivo]

Injection of intact bone marrow cells to mice at the peak of the secondary immune response results in a 2.4-fold increase of the number of antibody-forming cells in the regional lymph node. Preliminary injection of bone marrow cells to donors of the immune lymph node cells decreases the stimulation effect of antibody formation when the lymph node cells are subsequently cultivated with the intact bone marrow cells. The data obtained demonstrate the cell interaction at the level of mature antibody producers in vivo.     

Effect of catamine AB on the generative function and chromosome apparatus of the bone marrow cells in white rats

In a chronic experiment (6 months) performed on non-inbred white rats effect of cationic superficially active substance catamin AB on the structure and function of male and female gonads, state of the offspring and on the chromosome apparatus of the bone marrow cells has been studied. The preparation is intragastrically injected in doses 10, 1, 0.1 mg/kg. Catamin AB in the dose of 10 mg/kg produces an essential decrease in the specific mass of the testes, reduce in the spermatogenic index, increase in the canaliculi number with exfoliated epithelium, lowered mobility and diminished amount of alive spermatozoa. In the ovary amount of mature follicles becomes less and the number of atresic corpuscles and atresing follicles rises; plethora of the medullary substance occurs in the organ with signs of stasis in the venous bed. In the dose 1 mg/kg catamin AB results in less pronounced changes in the testes and does not produce any pathological disturbances in the ovaries. The preparation does not influence on mating in the test animals, but in the dose 10 mg/kg results in a decreasing fertility because of pre- and postimplantational death of embryos. The changes mentioned are connected with a total toxical effect of the preparation. Catamin AB does not possess any mutagenic effect in the doses tested.     

Leucokinetic study. Morphology of the bone marrow and blood after experimental induction of marrow hypoplasia by cyclophosphamide in laboratory rats

Experimental hypoplasia of femoral bone marrow in rats was induced by cyclophosphamide, injected i.p. at various clock hours (08.00, 12.00, 16.00, 20.00, 24.00, and 04.00). Cyclophosphamide-induced neutropenia persisted for six days and was followed by transitory granulocytosis with subsequent decrease in the cont of circulating mature granulocytes. The absolute counts of circulating segmented neutrophils changed in parallel with the absolute counts of segmented neutrophils in the bone marrow. The count of circulating neutrophils was not essentially influenced by the clock hour of cyclophosphamide injection. The toxic action of cyclophosphamide upon the bone marrow exhibited a circadian rhythmicity: the greatest decrease in the count of nucleated marrow cells was found in the morning, and the least, in the evening. The minimal compartment transit times of the development stages of bone-marrow neutrophils, and the daily granulocyte production in the rat were calculated.     

Bone formation in bone marrow organ cultures

Bone tissue composed of typical bone trabeculae containing ground substance with incorporated osteogenic cells and osteoblast layer was formed in organ cultures of bone marrow obtained from adult mice. Electron microscopic properties of the bone formed in vitro were identical to those of the bone tissue in vivo. The mineralization of the bone took place only in the presence of Na-beta-glycerophosphate in the culture medium.     

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.     

Haemoglobin types in peripheral blood and bone marrow cells in rats after a single blood loss.

The authors studied quantitative changes in the synthesis of haemoglobin types in rat peripheral erythrocytes and in the cells of the bone marrow erythrocytic series after a single blood loss. They demonstrated that raised synthesis of given haemoglobin types could be found in the peripheral cells 5-7 days after blood loss. These changes could already be detected in the bone marrow cells 24 hours after blood loss. The question of the probable site and level of the origin of altered haemoglobin synthesis is discussed.     

Bone formation in organ cultures of bone marrow

Summary Bone formation in organ cultures of intact marrow fragments from mouse is described. Marrow explants were cultured on the top surface of a millipore filter at a gas-liquid interface. Observations with both light- and electron microscopes demonstrated the formation of a well-organised trabecular matrix lined with osteoblast-like cells. The tissue and cells were positive for alkaline-phosphatase activity. Large amounts of thick, well-banded collagen fibrils and matrix vesicles typical of those found in bone were present. The tissue became mineralised in the presence of 10 mM Na--glycerophosphate; in its absence a similar trabecular matrix developed but mineralisation did not take place.     

Suppression of antibody formation by bone marrow T-cells activated by histocompatibility antigens]

The suppressive effect of the bone marrow T-cells activated by histocompatibility antigens on antibody formation was studied. The bone marrow of CBA mice was found to contain the thymus-dependent lymphocytes which underwent hyperactivation after the repeated transfers to F1 recipients and acquired the capacity ot inhibit the development of cooperative immune response to sheep erythrocytes. Pretreatment of the bone marrow cells with antithymocyte globulin and complement prevented the suppression.     

Bone formation in vitro by stromal cells obtained from bone marrow of young adult rats

Summary Cells from fetal or neonatal skeleton can synthesize bone-like tissue in vitro. In contrast, formation of bone-like tissue in vitro by cells derived from adult animals has rarely been reported and has not been achieved using cells from bone marrow. We have explored development of bone-like tissue in vitro by bone marrow stromal cells. Marrow stromal cells obtained from 40–43-day-old Wistar rats were grown in primary culture for 7 days and then subcultured for 20–30 days. Cells were cultured in either -minimal essential medium containing 15% fetal bovine serum, antibiotics, and 50 g/ml ascorbic acid, or the above medium supplemented with either 10 mM Na--glycerophosphate, 10^-8 M dexamethasone, or a combination of both. Cultures were examined using phase-contrast microscopy, undemineralized and demineralized tissue histology, histochemistry (for alkaline phosphatase activity), immunohistochemistry (for collagen type, osteonectin, and bone Glaprotein), scanning and transmission electron microscopy, energy dispersive X-ray microanalysis, and X-ray diffraction. Collagenous, mineralized nodules exhibiting morphological and ultrastructural characteristics similar to bone were formed in the cultures, but only in the presence of both -glycerophosphate and dexamethasone. Cells associated with the nodules exhibited alkaline phosphatase activity. The matrix of the nodules was composed predominantly of type-I collagen and both osteonectin and Glaprotein were present. X-ray microanalysis showed the presence of Ca and P, and X-ray diffraction indicated the mineral to be hydroxyapatite. The nodules were also examined for bone morphogenetic protein-like activity. Paired diffusion chambers containing partly demineralized nodules and fetal muscle were implanted intraperitonealy in rats. Induction of cartilage in relation to muscle was observed histologically after 40 days in the chambers. This finding provided further support for the bone-like nature of the nodules. The observations show that bone-like tissue can be synthesized in vitro by cells cultured from young-adult bone marrow, provided that the medium contains both -glycerophosphate and, particularly, dexamethasone.