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Stimulation of human osteoblast differentiation and function by ipriflavone and its metabolites (1994)

Cheng, S. -L. ; Zhang, S. -F. ; Nelson, T. L. ; [et al.]

Springer

Calcified tissue international 55 (1994), S. 356-362

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ISSN: 1432-0827

Keywords: Osteoblasts ; Matrix proteins ; Collagen ; Cell differentiation ; Calcification

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine , Physics

Notes: Abstract Ipriflavone (IP), an isoflavone derivative, has been shown to interfere with bone remodeling by inhibiting bone resorption and perhaps stimulating bone formation. In this study, we have analyzed the effect of IP and its metabolites on the differentiation and function of human osteoblastic cells. Bone marrow stromal osteoprogenitor cells (BMC) and trabecular bone osteoblasts (HOB) were isolated from human donors. The former can be induced to differentiate by treatment with dexamethasone, whereas the latter represent a more differentiated osteoblast. Incubation of BMC with metabolite III (10-5 M) for 1 week induced modest but significant changes of alkaline phosphatase activity. Though both IP and metabolite III stimulated the expression of bone sialoprotein mRNA, a protein involved in cell attachment to the matrix, only metabolite III increased the steady-state level of decorin mRNA, a collagen fibrillogenesis-regulating proteoglycan. Metabolites III and V, but not the other isoflavones, increased the expression of type I collagen mRNA in HOB, whereas no detectable changes were observed in BMC cells with any of the experimental compounds. In HOB, an increased abundance of osteopontin and bone sialoprotein mRNA were also obtained after 1-week treatment with IP or metabolite V. No appreciable effects of IP or its metabolites were seen on osteocalcin expression and synthesis by either cell type. Finally, IP consistently increased the amount of 45Ca incorporated into the cell layer by BMC, and stimulated mineralization of both BMC and HOB, assessed by von Kossa staining. Thus, IP and its metabolites regulate the differentiation and biosynthetic properties of human bone-forming cells by enhancing the expression of some important matrix proteins and facilitating the mineralization process.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00299315

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Determination of pollutant diffusion coefficients in naturally formed biofilms using a single tube extractive membrane bioreactor (1998)

Zhang, S.-F. ; Splendiani, A. ; dos Santos, L. M. Freitas ; [et al.]

New York, NY [u.a.] : Wiley-Blackwell

Biotechnology and Bioengineering 59 (1998), S. 80-89

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ISSN: 0006-3592

Keywords: effective diffusion coefficient ; biofilm reactor ; biofilm thickness ; mass transfer ; silicone rubber membrane ; Chemistry ; Biochemistry and Biotechnology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology

Notes: A novel technique has been used to determine the effective diffusion coefficients for 1,1,2-trichloroethane (TCE), a nonreacting tracer, in biofilms growing on the external surface of a silicone rubber membrane tube during degradation of 1,2-dichloroethane (DCE) by Xanthobacter autotrophicus GJ10 and monochlorobenzene (MCB) by Pseudomonas JS150. Experiments were carried out in a single tube extractive membrane bioreactor (STEMB), whose configuration makes it possible to measure the transmembrane flux of substrates. A video imaging technique (VIT) was employed for in situ biofilm thickness measurement and recording. Diffusion coefficients of TCE in the biofilms and TCE mass transfer coefficients in the liquid films adjacent to the biofilms were determined simultaneously using a resistances-in-series diffusion model. It was found that the flux and overall mass transfer coefficient of TCE decrease with increasing biofilm thickness, showing the importance of biofilm diffusion on the mass transfer process. Similar fluxes were observed for the nonreacting tracer (TCE) and the reactive substrates (MCB or DCE), suggesting that membrane-attached biofilm systems can be rate controlled primarily by substrate diffusion. The TCE diffusion coefficient in the JS150 biofilm appeared to be dependent on biofilm thickness, decreasing markedly for biofilm thicknesses of 〉 1 mm. The values of the TCE diffusion coefficients in the JS150 biofilms 〈1-mm thick are approximately twice those in water and fall to around 30% of the water value for biofilms 〉 1-mm thick. The TCE diffusion coefficients in the GJ10 biofilms were apparently constant at about the water value. The change in the diffusion coefficient for the JS150 biofilms is attributed to the influence of eddy diffusion and convective flow on transport in the thinner (〈1-mm thick) biofilms. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 59:80-89, 1998.

Additional Material: 11 Ill.

Type of Medium: Electronic Resource

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