Effect of plasterboard composition on Stachybotrys chartarum growth and biological activity of spores.
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The effects of plasterboard composition on the growth and sporulation of Stachybotrys chartarum as well as on the inflammatory potential of the spores were studied. S. chartarum was grown on 13 modified plasterboards under saturated humidity conditions. The biomass was estimated by measuring the ergosterol content of the S. chartarum culture while the spore-induced cytotoxicity and production of nitric oxide (NO), tumor necrosis factor alpha (TNF-alpha), and interleukin-6 in mouse macrophages was used to illustrate the bioactivity of spores. The ergosterol content of S. chartarum correlated with the number of spores collected from plasterboards. The growth and sporulation decreased compared to that of the reference board in those cases where (i) the liner was treated with biocide, (ii) starch was removed from the plasterboard, or (iii) desulfurization gypsum was used in the core. Spores collected from all the plasterboards were toxic to the macrophages. The biocide added to the core did not reduce the growth; in fact, the spores collected from that board evoked the highest cytotoxicity. The conventional additives used in the core had inhibitory effects on growth. Recycled plasterboards used in the core and the board lacking the starch triggered spore-induced TNF-alpha production in macrophages. In summary, this study shows that the growth of a strain of S. chartarum on plasterboard and the subsequent bioactivity of spores were affected by minor changes to the composition of the core or liners, but it could not be totally prevented without resorting to the use of biocides. However, incomplete prevention of microbial growth by biocides even increased the cytotoxic potential of the spores. (+info)
Quantifying mold biomass on gypsum board: comparison of ergosterol and beta-N-acetylhexosaminidase as mold biomass parameters.
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Two mold species, Stachybotrys chartarum and Aspergillus versicolor, were inoculated onto agar overlaid with cellophane, allowing determination of a direct measurement of biomass density by weighing. Biomass density, ergosterol content, and beta-N-acetylhexosaminidase (3.2.1.52) activity were monitored from inoculation to stationary phase. Regression analysis showed a good linear correlation to biomass density for both ergosterol content and beta-N-acetylhexosaminidase activity. The same two mold species were inoculated onto wallpapered gypsum board, from which a direct biomass measurement was not possible. Growth was measured as an increase in ergosterol content and beta-N-acetylhexosaminidase activity. A good linear correlation was seen between ergosterol content and beta-N-acetylhexosaminidase activity. From the experiments performed on agar medium, conversion factors (CFs) for estimating biomass density from ergosterol content and beta-N-acetylhexosaminidase activity were determined. The CFs were used to estimate the biomass density of the molds grown on gypsum board. The biomass densities estimated from ergosterol content and beta-N-acetylhexosaminidase activity data gave similar results, showing significantly slower growth and lower stationary-phase biomass density on gypsum board than on agar. (+info)
Effect of processing variables (different compression packing processes and investment material types) and time on the dimensional accuracy of polymethyl methacrylate denture bases.
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In this study we determined the effect of different compression packing processes, investment materials (a hemihydrate and dental stone) and time on the dimensional accuracy of polymethyl metacrylate denture bases. Square stainless steel plates (15 mm x 15 mm x 5 mm) were prepared to make an acrylic resin specimen. The linear dimensional changes of acrylic resin were determined by measuring the distances of fix points. Measurements were made at 24 hours, 48 hours, 12 days and 30 days after setting with a digital compass. Dimensional changes of test specimens that were obtained with three different flasks and two press techniques were compared by univariate analysis. Measurements of the linear dimensions of specimens cured by different compression packing techniques suggested that differences existed. The time interval differences were not significant. According to the results; flask and investment material types affect the dimensional accuracy of test specimens (p < 0.05). The least dimensional change observed in the specimens was obtained with Type 1 flask-dental stone-manual press combinations. (+info)
Intracorporal bone grafting for vertebral compression fractures with intraosseous vacuum phenomenon.
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From April 1998 to January 2000 we treated 14 patients with vertebral osteoporotic compression fractures and intraosseous vacuum phenomenon with intracorporal bone grafting using a mixture of autogenous bone graft and calcium sulfate and posterior instrumentation. The mixture was packed into the fractured vertebral body through two tunnels created in the pedicles. Eleven patients were followed for a minimum of 24 months. All vertebral bodies healed. There were no perioperative complications. The average vertebral height restoration was 31%. On the visual analogue scale, there was an improvement of average 37 clinical scores. (+info)
A novel human hepatoblastoma cell line (HuH-6KK) with rapid growth in serum-free medium without extracellular matrix.
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A novel human hepatoblastoma cell line (HuH-6KK) with a high growth rate in a serum-free medium without extracellular matrix was developed from an original one, HuH-6 c15 (HuH). The original HuH cells (38 passages) did not proliferate well in RPMI 1640 medium containing 20% fetal calf serum (FCS). The HuH cells (HuH-6KK) with a high growth rate were selected by culturing them in an enriched RDF containing 20% FCS and 0.01% mucous polysaccharide (spirulinan) isolated from a blue-green alga, Spirulina subsalsa. The HuH-6KK cells showed a rapid growth in serum-free eRDF medium containing insulin, transferrin, ethanolamine, and selenite (eRDF-ITES medium) without fibronectin. The proliferation of the original HuH cells was also observed in the eRDF-ITES medium, but the growth was slow compared with the HuH-6KK cells. In the medium without ITES, the growth of the HuH-6KK and original HuH cells was slow. Among the ITES ingredients, insulin promoted the growth of HuH-6KK cells the most. (+info)
Cavitation bubble cluster activity in the breakage of kidney stones by lithotripter shockwaves.
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BACKGROUND AND PURPOSE: There is strong evidence that cavitation bubble activity contributes to stone breakage and that shockwave-bubble interactions are involved in the tissue trauma associated with shockwave lithotripsy. Cavitation control may thus be a way to improve lithotripsy. MATERIALS AND METHODS: High-speed photography was used to analyze cavitation bubble activity at the surface of artificial and natural kidney stones during exposure to lithotripter shockwaves in vitro. RESULTS: Numerous individual bubbles formed on the surfaces of stones, but these bubbles did not remain independent but rather combined to form clusters. Bubble clusters formed at the proximal and distal ends and at the sides of stones. Each cluster collapsed to a narrow point of impact. Collapse of the proximal cluster eroded the leading face of the stone, and the collapse of clusters at the sides of stones appeared to contribute to the growth of cracks. Collapse of the distal cluster caused minimal damage. CONCLUSION: Cavitation-mediated damage to stones is attributable, not to the action of solitary bubbles, but to the growth and collapse of bubble clusters. (+info)
Prophylactic effect of plaster and cataplasm contained ketoprofen in rats with adjuvant arthritis.
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This study demonstrates that prophylactic effect of plaster and cataplasm contained ketoprofen in adjuvant arthritis therapy by X-ray. Adjuvant arthritis was induced by a single injection of Freund's complete adjuvant. Mature female Sprague-Dawley rats were designated to 3 groups such as nontreated control, plaster-treated (PT) and cataplasm-treated (CT), each of which was composed of ten animals. The PT and the CT groups showed reduced primary paw swelling, but secondary paw swelling was not affected. Bony changes were observed in all regions of the femur and tibia of the nonadjuvant-injected leg and the adjuvant-injected leg. The mean radiographic scores of the PT and the CT groups were significantly lower than those of the control group from day 0 to 7 of the experimental period (P<0.05, P<0.01). The CT rats showed reduced poly-arthritis development than the PT rats. Our results suggest that radiographic assessment of bony changes is more suitable for measuring changes in long bones such as femur or tibia than in vertebrae. The prophylactic effect of CT prominently suppressed edematous swelling and bony changes in arthritic limb compared with PT. (+info)
Development of casting investment preventing blackening of noble metal alloys Part 2. Application of developed investment for type 4 gold alloy.
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The objective of this study was to evaluate the efficacy of the developed investment for the prevention of blackening of a cast Type 4 gold and to analyze the oxides on its surface in relation to the blackening of the alloy. The experimental investments were prepared using a gypsum-bonded investment in which boron (B) or aluminum (Al) was added as a reducing agent. A Type 4 gold alloy was cast into the mold made of the prepared investment. The effect of the additives was evaluated from the color difference (deltaE*) between the as-cast surface and the polished surface of the cast specimen. B and Al were effective to prevent the blackening of a Type 4 gold alloy and the color of the as-cast surface approached that of the polished surface with increasing B and Al content. The prevention of the blackening of the gold alloy can be achieved by restraining the formation of CuO. (+info)