Bone-forming cells, effect

Phenol (25, 50, 75 or 100 mg/kg, single intraperitoneal administration) decreased the incorporation of Fe by erythrocytes in a dose-dependent fashion in female Swiss mice, when administered with hydroquinone (50 mg/kg, single intraperitoneal administration) (Snyder et al., 1989). Phenol (< 40 pmol/L) had no consistent effect on the number of erythroid colony-forming bone-marrow cells from Swiss Webster or C57BL/J6 mice (Neun et al., 1992) and only inhibited the growth of bone-marrow cells from female C57 BL/6 X DBA/2 mice at millimolar concentrations (Seidel et al., 1991). 

Figure 9.6 Effect of a fusion protein on ERK phosphorylation in activated mouse and human cells. Mouse bone marrow cells (a) and human cord blood cells (b) were activated with antireceptor Ab for 5,10, and 15 minutes, lysed, and the total proteins loaded on a SDS-Page gel. After transfer to a membrane, ERK phosphorylation was detected using antibodies specific for the phosphorylated (active, P-ERK) form of ERK (upper blots). As a control for the amount of ERK in the samples, antibodies specific for total ERK (activated and nonactivated forms) were used (lower blots). Unstimulated cells untreated (lane 1) and treated with biopharmaceutical Y (lane 2) were used as controls. Cells were activated for 5 minutes (lanes 3, 4), 10 minutes (lanes 5, 6), or 15 minutes (lanes 7, 8) in the absence (lanes 3, 5, 7) or presence (lanes 4, 6, 8) of biopharmaceutical Y.

To understand osteoporosis, it is helpful to understand the basics of bone formation. Bone is formed on a protein base (collagen) by the deposition of minerals, particularly calcium. This laying down of bone is carried out by specialized cells called osteoblasts. The formation of new bone occurs most effectively along lines of stress/weight that are experienced by the bone. 

There has been very little experimental work conducted with natural products from the phylum Bryozoa. The family of bryostatins, macrolide polyketides isolated by Pettit from the bryozoan Bugula neritina, is certainly of greatest significance in terms of biomedical potential [92]. Bryostatin 1 (57) exhibits selective activity against B-cell lymphomas and leukemias, [93] and directly stimulates bone marrow progenitor cells to form colonies that functionally activate neutrophils [94]. Additionally, bryostatin 1 activates protein kinase C [95] and has immunomodulatory activity both in vitro and in vivo [96]. In combination with the vinca alkaloid vincristine, bryostatin 1 inhibits the growth of lymphoma cells without adverse effects on bone marrow cells [97]. 

To clarify the mechanism of action of these diterpenoids on bone resorption, their effect on osteoclast-like cell formation was tested according to the method reported by Takahashi et al.[34]. As a result, both compounds dose-dependently inhibited PTH-induced tartrate resistant acid phosphatase-positive MNC formation. Especially, SDC showed complete inhbition at concentration over 0.1 pM. Next, the effect of SDB and SDC on resorbing activity of osteoclasts (pit forming activity of osteoclast-like cells) was assayed according to the method of Tamura et al. [35]. As indicated in Table 8, both compounds inhibited the pit-formation when osteoclasts obtained by the co-culture were placed on dentine slice in the presence of these compounds. Therefore, the inhibitory effect of... 

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