Biochemical characterization of embryonic chick calvarial cells / 대한치과교정학회지

Chicken calvarial bone is known to contain various cell types, but their exact composition is unknown. By characterizing the chicken calvarial bone biochemically, it can be used to study biochemical, histochemical actions of bone cells in general. Calvaria of I8-day-old white leg horn embryo was aseptically dissected and bone cell populations were isolated by sequential enzymatic digestion. Histochemical study for osteoclast-like bone cell population was performed with tartrate resistant acid phosphatase(TRAP) stain and for osteoblast-like bone cell population, alkaline phosphatase(ALP) stain was performed. Biochemical study for osteoblast-like bone cell population was performed using alkaline phosphatasetal.P) assay. Following conclusions were obtained from this study. 1. TRAP positive multi and mononuclear cells were mostly observed in group I and II, indicating that osteoclast-like bone cell population is mostly found in these groups. 2. All the cultured groups showed almost equal ALP activities and were positive for ALP stain, indicating that osteoblast-like bone cell population is evenly dispersed in all culture groups. 3. Experimental group treated with I,25(OH)2D3 showed increase in ALP activity in contrast to the control group, confirming previous studies that I,25(OH)2D3 increases ALP activities in vitro bone cultures. 4. Results from von Kassa's stain indicated that in vitro bone formation had occured after 3 weeks of culture with beta glycero phosphate.

Effects of nitric oxide synthase inhibitors on osteoclast-like cell formation / 대한치과교정학회지

Orthodontic tooth movement in response to orthodontic force results from actions of osteoclasts and osteoblasts in the cell level. Convincing evidence has now been provided to support the view that osteoclasts are derived from mononuclear cells that originate in the bone marrow or other hematopoietic organs and they migrate to the bones via vascular routes. Nitric oxide(NO), which accounts for the biological properties of endothelium-derived relaxmg factor(EDRF), is the endogenous stimulator of soluble guanylate cylase. The discovery of the formation of nitric oxide(NO) from L-arginine in mammalian tissues and its biologioal roles has, in the last 7 years, thrown new light onto many areas of research. Data from experiments in vitro showed that N-metyl-L-arginine(L-NMA) and L-nitro-L-arginine(L-NAME) are competitive inhibitors of nitric oxide synthase. This study suggest that the multinucleated cells in our culture have characteristics of osteoclasts and that the potential bone cell activity of nitric oxide in vitro may be mediated in part by stimulation of marrow mononuclear cells to form osteoclast-like cells. Bone marrow cells were obtained from tibia of 19-days old chick embryo. After sacrifice, tibia was quickly dissected and the bone were then split to expose the medullary bone. The cells were attached for 4 hours and the nonadherent cells were collected. Marrow cells were cultured in 96-well plate in medium 199. To examine the number of TRAP-positive multinucleated cells(MNCs), 10(-8) M Vit-D3 and various concentration of L-NMA and L-NAME were added at the beginning of cultures and with each medium change. After 7 days of culture, tartrate-resistant acid phosphatase(TRAP) staining was performed for microscopic evaluation. Cells having more than three nuclei per cell were counted as MNCs. The observed results were as follows; 1. 1,25-dihydroxyvitamine D3 stimulated the osteoclast-like multinucleated cells in cultures of chick embryo bone marrow. 2. Nitric oxide synthase inhibitors(NOSI ; N-NMA, N-NAME) stimulated the osteoclast-like cells in cultures of chick embry bone marrow. 3. 1,25-dihydroxyvltamine D3 and nitric oxide synthase inhibitors did not appear to have additive effect on the generation of TRAP-positive MNCs. These results suggest that nitric oxide synthase inhibitors may stimulate the osteoclast-like multinucleated cell formation and fusion in cultures of chick bone marrow.

Effects of sodium nitroprusside on the formation and activation of the osteoclast in culture / 대한치과교정학회지

Due to the great deal of effort that has gone into the study of osteoclastic differentiation and activation over the last few decades, the mechanisms of these two events have been discovered gradually. Nitric oxide(NO-), which is produced from arginine by a nitric oxide synthase, opened up a new area of biological research. Recently, it has been reported that NO- is produced by osteoblasts stimulated by lipopolysaccharide and several other cytokines. In this study, the effect of sodium nitroprusside(SNP), a donor of nitric oxide(NO-), on osteoclast-like cell formation and on mature osteoclast function was examined. To determine the mechanism of the inhibitory effects of SNP decreased not only the basal 45Ca release but also thee bone resorption induced by PTH and l,25-dihydroxyvitamin D3 (I ,25[OH]2D3). The inhibitory effect of SNP on bone resorption induced by PTH appeared 2 days after treatment, whereas SNP effect on inhibiting bone resorption induced by l,25[OH]2D3 appeared at the third days. When chicken and rat osteoclasts were cultured on dentin slices, treatment of 300micronM SNP resulted in a significant decrease in dentin resorption by osteoclasts in terms of total resorption area and average individual area. We also examined the effect of SNP on formation of osteoclast-like cells that is TRAP-positive multinucleated cells from chicken and rat bone marrow cells in the presence or absence of 10(-8)M l,25[OH]2D3. The addition of 300 micronM SNP inhibited the formation of TRAP-positive multinucleated cells. The present data suggest that SNP, possibly as a NO- donor, inhibits the osteoclastic differentiation and osteoclastic activity.

A case of leiomyosarcoma of ovary / 대한산부인과학회잡지

No abstract available.