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At least 667 records · Page 37Linked to original sources
PubMed1982

A cellular investment of bone marrow.

We describe a method for clearly separating the cell layers at the bone-marrow interface, which reveals that the myeloid tissue is invested by an epithelial-like layer of specialized squamous cells we call the marrow sac. The scanning electron microscope showed that the sac was fenestrated and that some of its cells pass as perivascular elements with the marrow capillaries that penetrate the bony cortex. The transmission electron microscope (TEM) showed that the cells comprising the marrow sac are less than 0.1 micrometer thick, overlap at their margins without specialized cell junctions, and are more electron dense than the reticular or fibroblastic cells of the marrow stroma. The fenestrations in the sac were intercellular and were usually occupied by cells having an ultrastructure compatible with an osteoprogenitor cell (OPC) lineage. The observation of a close proximity between the cells of the marrow sac and the osteogenic cells that line the endosteal surfaces of bone suggest that the sac cells, along with the OPCs of the superficial marrow stroma, should be included in any morphological or functional definition of an endosteum.

Animals↗
PubMed1982

Cellular changes in bone marrow of malaria-infected mice. III. Chemotaxis of granulocytes.

The number of bone marrow cells and their chemotactic activity was studied during malaria infection. Two days after infection of Balb/c mice with Plasmodium berghei, an increase in granulocyte number was observed in the blood. A modified Boyden chamber chemotaxis assay was employed to investigate the mechanism of granulocyte accumulation in the blood. Bone marrow cells from normal mice, from mice during a primary lethal infection and from immune mice after challenge were compared. The complement factor C5a showed chemotactic activity for bone marrow cells; a significant decrease of chemotaxis was only observed after 6 days of primary infection. Extracts of spleen, liver and infected erythrocytes lacked chemotactic activity, or caused inhibition of cell migration. Serum from mice with a 2-day primary infection contained chemotactic activity. The active component was heat labile, protease sensitive and had an estimated molecular weight of 250,000.

Animals↗
PubMed2000

Distribution of enzyme-bearing cells in GM2 gangliosidosis mice: regionally specific pattern of cellular infiltration following bone marrow transplantation.

Tissue distribution of beta-hexosaminidase was investigated using 5-bromo-4-chloro-3-indolyl N-acetyl beta-D-glucosaminide (X-Hex) as substrate in wild-type mice, four GM2 gangliosidosis model mice (Hexa-/-, Hexb-/-, Gm2a-/- and Hexa-/-Hexb-/-) and Hexb-/- mice that received bone marrow transplantation (BMT). In wild-type mice histochemical localization of beta-hexosaminidase was detected in the perikarya of the majority of neurons, small process-bearing microglial cells, perivascular macrophages, and macrophages in the choroid plexus and leptomeninges. X-Hex positivity was also noted in the renal tubular epithelium and macrophages in the liver and spleen. The staining pattern in the Gm2a-/- and Hexa-/- mice was generally similar to those of wild type, but in these mice, X-Hex stain was also noted in some storage neurons with swollen perikarya. No X-Hex-positive cells were detected in Hexb-/- or Hexa-/-Hexb-/- (DKO) mice. In Hexb-/- mice that received wild-type BMT (Hexb-/- +WBMT), many X-Hex-positive cells were detected in the spleen, and to a far lesser extent, in liver and kidney. In the CNS of these mice, X-Hex-positive cells were largely detected in the leptomeninges and choroid plexus. Some positive cells were also detected, mostly in the perivascular regions of the cerebrum, in particular in the regions of the posterior thalamus, brain stem and spinal cord. Some of X-Hex-positive cells were immunoreactive with Mac-1 and F4/80 antibodies and, thus, were cells of microglia/macrophage lineage. X-Hex-positive staining was not detected in neurons in these mice despite clinical improvement following BMT. This is the first time, as far as we know, that the regional distribution of the donor cells in the CNS has been investigated in a model of neuronal storage disease. Our study indicated that donor-derived cells of microglia/macrophage lineage infiltrated the CNS in a regionally specific manner following the BMT.

Animals↗
PubMed2006

Analyzing the cellular contribution of bone marrow to fracture healing using bone marrow transplantation in mice.

The bone marrow is believed to play important roles during fracture healing such as providing progenitor cells for inflammation, matrix remodeling, and cartilage and bone formation. Given the complex nature of bone repair, it remains difficult to distinguish the contributions of various cell types. Here we describe a mouse model based on bone marrow transplantation and genetic labeling to track cells originating from bone marrow during fracture healing. Following lethal irradiation and engraftment of bone marrow expressing the LacZ transgene constitutively, wild type mice underwent tibial fracture. Donor bone marrow-derived cells, which originated from the hematopoietic compartment, did not participate in the chondrogenic and osteogenic lineages during fracture healing. Instead, the donor bone marrow contributed to inflammatory and bone resorbing cells. This model can be exploited in the future to investigate the role of inflammation and matrix remodeling during bone repair, independent from osteogenesis and chondrogenesis.

Animals↗
PubMed2001

Age- and gender-related changes in the cellularity of human bone marrow and the prevalence of osteoblastic progenitors.

Bone marrow harvested by aspiration contains connective tissue progenitor cells which can be induced to express a bone phenotype in vitro. The number of osteoblastic progenitors can be estimated by counting the colony-forming units which express alkaline phosphatase (CFU-APs). This study was undertaken to test the hypothesis that human aging is associated with a significant change in the number or prevalence of osteoblastic progenitors in the bone marrow. Four 2-ml bone marrow aspirates were harvested bilaterally from the anterior iliac crest of 57 patients, 31 men (age 15-83) and 26 women (age 13-79). A mean of 64 million nucleated cells was harvested per aspirate. The mean prevalence of CFU-APs was found to be 55 per million nucleated cells. These data revealed a significant age-related decline in the number of nucleated cells harvested per aspirate for both men and women (P = 0.002). The number of CFU-APs harvested per aspirate also decreased significantly with age for women (P = 0.02), but not for men (P = 0.3). These findings are relevant to the harvest of bone marrow derived connective tissue progenitors for bone grafting and other tissue engineering applications, and may also be relevant to the pathophysiology of age-related bone loss and post-menopausal osteoporosis.

Adolescent↗
PubMed1992

Effects of prolonged processing in standard and isotonic trichloroacetic acid (TCA) on cellular preservation in bone marrow trephines.

The effects of a combined fixing and decalcifying solution, trichloroacetic acid, on prepared bone marrow specimens were evaluated to try to improve the speed of trephine biopsy processing in our laboratory. The morphological preservation obtained immediately after decalcification was complete was assessed, and also after prolonged immersion in each of two solutions. Trichloracetic acid was made up in the standard manner using distilled water and in an isotonic form by the addition of sodium chloride. Prolonged immersion was performed to assess any possible adverse effects of this acidic solution. By the time decalcification was complete, each solution gave morphological preservation sufficient for diagnostic purposes. However, after prolonged immersion, only the isotonic solution performed adequately.

Biopsy↗
PubMed1999

Automated enumeration of cellular composition in bone marrow aspirate with the CELL-DYN 4000 automated hematology analyzer.

The present study was designed to evaluate the automated analysis of bone marrow aspirates with the CELL-DYN 4000 (CD4000) hematology analyzer. Bone marrow aspirates were diluted twice with phosphate-buffered saline and assayed with the CD4000. The percentages of subpopulations including lymphocytes, neutrophils, and erythroblasts were obtained with the CD4000, and as a reference, differential counts by microscopic observation of May-Grünwald-Giemsa-stained films of bone marrow aspirate were performed (n = 48). Significant correlations (p < 0.0001) between the results with the two methods were obtained for total nucleated cell count, lymphocytes, neutrophils, erythroid cells, and the myeloid/erythroid ratio. The present method can provide quantitative data of bone marrow aspirate and will be useful in bone marrow screening.

Biopsy, Needle↗