Chromatography, Gas ; Humans ; Methylene Chloride ; urine

STATEMENT OF PROBLEM: The failure of adhesion between the resilient denture liner and the denture base is a serious problem in clinic. PURPOSE: The PURPOSE of this study was to evaluate the effect of denture base resin surface pretreatments (mechanical and/or chemical) on the tensile bond strength between a resilient liner and processed denture resin. MATERIAL AND METHOD: Acrylic-based resilient liners (Soft liner; GC co., Japan & Coe-Soft; GC America Inc. USA) and silicone-based resilient liners (Mucosoft; Parkell Inc., USA & Dentusil; Bosworth co., USA) were used. Specimens in each soft lining material were divided two groups with or without mechanical pretreatment. Each denture base specimen received 1 of 4 chemical pretreatments including: (1) no treatment, (2) 30-s acetone treatment, (3) 15-s methylene chloride treatment, (4) 180-s methyl methacrylate treatment. All specimens were thermocycled and placed under tension until failure in a universal testing machine. RESULTS: 1. Silicone-based resilient liners exhibited significantly higher tensile bond strengths than acrylicbased resilient liners (P<.05). 2. Grinding the denture base resin improved tensile bond strengths of silicone-based resilient liners, but reduced tensile bond strengths of acrylic-based resilient liners (P<.05). 3. In acrylic-based resilient liners, treating with acetone significantly increased the bond strength of Soft liner and treating with methyl methacrylate significantly increased the bond strength of Coe-Soft (P<.05). However they were not effective compared to silicone-based resilient liner. 4. In silicone-based resilient liners, treating with all chemical etchants significantly increased the bond strength of Mucosoft to denture base, and treating with methylene chloride and methyl methacrylate increased the bond strength of Dentusil to denture base (P<.05). CONCLUSION: Although chemical and mechanical pretreatments were not effective on tensile bond strength of acrylic-based resilent liner to denture base, treating the denture base resin surface with appropriate chemical etchants after mechanical pretreatment significantly increased the tensile bond strength of silicone-based resilient liner to denture base.
Acetone ; Americas ; Denture Bases* ; Denture Liners ; Dentures* ; Japan ; Methylene Chloride

Animals ; Liver ; drug effects ; Methylene Chloride ; toxicity ; Mice ; Oxidative Stress

Air ; analysis ; Chromatography, Gas ; methods ; Methylene Chloride ; analysis ; Workplace

The purpose of this study was to evaluate the effects of DFPR on differentiation of mouse calvarial cell in vitro, to examine the possibility for periodontal regeneration. 10microgram/ml of DFPR was used as experimental concentration. osteogenic medium only was assigned as control, Experimental 1 was supplemented with 10nM dexamethasone, Experimental 2 with 10microgram/ml DFPR and Experimental 3 with 10nM dexamethasone + 10microgram/ml DFPR. cellular activity was evaluated by MTT method at 8, 12, 16 days, expression of mRNA of ALP, osteopontin, osteocalcin, collagen type-1 was detected by RT-PCR method at 4, 8, 12, 16 days of culture . extent of mineralization was observed by Von Kossa staining at 16 day of culture. The results are as follows 1)Any acceleration of differentiation was not observed at expression of differentiation marker, 2) Decrease in expression of extracelluar matrix and in bone nodule formation was observed The results suggested that DFPR have negative effect on the rate of differentiation on rat calvarial cell, decrease extracelluar matrix formation ,decrease bone nodule formation. Ongoing studies are necessary in order to determine effect of DFPR on periodontal regeneration.
Acceleration ; Animals ; Collagen ; Dexamethasone ; Methylene Chloride* ; Mice* ; Osteocalcin ; Osteopontin ; Rats ; Regeneration ; RNA, Messenger

The half-dried leaves of Stewartia. pseudocamellia were extracted with hot water (SPE) and partitioned with n-hexane (SPEH), dichloromethane (SPED), and ethyl acetate (SPEE) successively. SPE and SPEE showed significant inhibitory effects against melanogenesis and tyrosinase activities. By bioassay-guided isolation, ten phenolic compounds were isolated by column chromatography from SPEE. The whitening effect of the isolated compounds from SPEE were tested for the inhibitory activities against melanogenesis using B16 melanoma cells, in vitro inhibition of tyrosinase, and L-3,4-dihydorxy-indole-2-carboxylic acid (L-DOPA) auto-oxidation assay. A cytotoxic activity assay was done to examine the cellular toxicity in Raw 264.7 macrophage cells. Of the compounds isolated, gallic acid and quercetin revealed significant inhibitory activities against melanogenesis compared to arbutin. In particular, quercetin exhibited similar inhibitory activities against tyrosinase and L-DOPA oxidation without cytotoxicity. These results suggested that SPE could be used as a potential source of natural skin-whitening material in cosmetics as well as in food products.
Arbutin ; Chromatography ; Gallic Acid ; Levodopa ; Macrophages ; Melanoma, Experimental ; Methylene Chloride ; Monophenol Monooxygenase ; Phenol* ; Quercetin ; Water

The ideal goal of periodontal therapy is the regeneration of periodontal tissue and repair of function. Although it is very difficult to attain this goal, recent advances in periodontal wound healing concepts encourage hope reaching it. Recently many efforts are concentrated on the regeneration potential of material used in traditional Korean medicine. Phlomidis Radix has been used for the treatment of blood stasis, bone fracture and osteoporosis in traditional Korean medicine. The purpose of this study is to examine effects of dichloromethane fraction Phlomidis Radix on Bone Formation in Human Fetal Osteoblasts. Human fetal osteoblastic cell line(hFOB1 1.19 ; American Type Culture Collection, Manassas, VA) were used and cells were cultured containing DMEM and dichloromethane fraction Phlomidis Radix(100 ng/ml, 1 microgram/ml, 10 microgram/ml) at 34degrees C with 5% CO2 in 100% humidity. MTT was performed to examine the viability of the cell, and alkaline phosphatase activity was analyzed to examnine the mineralization. Also bone calcification nodules were evaluated. The cellular activity of hFOB1 was increased in 100 ng/ml, 1 microgram/ml, 10 microgram/ml of dichloromethane fraction of Phlomidis Radix and especially significant increation was showed in 100 ng/ml of dichloromethane fraction of Phlomidis Radix at 6days (p<0.05). ALP level of hFOB1 was significantly increased in 100 ng/ml, 1 microgram/ml, 10 microgram/ml of dichloromethane fraction of Phlomidis Radix and especially more increation was showed in 10 microgram/ml of dichloromethane fraction of Phlomidis Radix (p<0.05). Calcification nodules of hFOB1 significantly increased in 10 microgram/ml of dichloromethane fraction of Phlomidis Radix at 21days of incubation (p<0.05). These results indicate that dichloromethane fraction of Phlomidis Radix has excellent effects on mineralization of hFOB1.
Alkaline Phosphatase ; Fractures, Bone ; Hope ; Humans* ; Humidity ; Methylene Chloride* ; Osteoblasts* ; Osteogenesis* ; Osteoporosis ; Regeneration ; Wound Healing

BACKGROUND: Workers who are related with paint stripping process of aircraft parts can be exposed methylene chloride, phenol, chromium hexavalent in using paint remover. Especially, methylene chloride is more important hazard because of chemical asphyxia. METHOD: NIOSH(National Institute of Occupational Safety and Health) Manual of Analytical Methods(NMAM) #1005 was used in sampling and analysis of methylene chloride. 4 air bases were surveyed. RESULT: Airborne concentrations of methylene chloride distributed lognomally. In aircraft paint stripping operation of 4 air bases, geometric mean(GM) of methylene chloride concentrations was 30.40+/-3.39 ppm (n=14) in personal samples and GM of area samples was 2.24 ppm (n=2). 5 of 8 samples showed breakthrough phenomenon. Breakthrough rate([back section]/[front section]) significantly correlated with airborne concentrations (p<0.01) and with detected amounts of methylene chloride(p<0.01). CONCLUSION: Airborne concentrations of methylene chloride in paint stripping process exceed the criteria level in many case(43%). Seriesed charcoal tubes must be used in methylene chloride sampling in compliance with NMAM.
Aircraft* ; Asphyxia ; Charcoal ; Chromium ; Compliance ; Humans ; Methylene Chloride* ; Occupational Health ; Paint* ; Phenol

This study explored the health hazard of those exposed to methylene chloride by assessing its atmospheric concentration when a tear gas mixture was aerially dispersed. The concentration of methylene chloride ranged from 311.1-980.3 ppm (geometric mean, 555.8 ppm), 30 seconds after the dispersion started. However, the concentration fell rapidly to below 10 ppm after dispersion was completed. The concentration during the dispersion did not surpass the National Institute for Occupational Safety and Health 'immediately dangerous to life or health' value of 2,300 ppm, but did exceed the American Conference of Governmental Industrial Hygienists excursion limit of 250 ppm. Since methylene chloride is highly volatile (vapor pressure, 349 mmHg at 20degrees C), the postdispersion atmospheric concentration can rise instantaneously. Moreover, the o-chlorobenzylidenemalononitrile formulation of tear gas (CS gas) is an acute upper respiratory tract irritant. Therefore, tear gas mixtures should be handled with delicate care.
Methylene Chloride ; National Institute for Occupational Safety and Health (U.S.) ; o-Chlorobenzylidenemalonitrile ; Respiratory System ; Tear Gases

Anticancer effect of methanol extract of Caesalpinia sappan L. on oral carcinoma (KB) and osteosarcoma (HOS) cells were investigated in this study. In order to elucidate the anticancer mechanism of Caesalpinia sappan L, we analyzed telomerase inhibitory effect of the methanol extract of Caesalpinia sappan L. In addition we prepared 5 fraction samples according to its polarity differences and analyzed anticancer effects on oral carcinoma and osteosarcoma cells. Following results are obtained in this study. 1. 50% cell proliferation inhibitory value (IC50) of the methanol extract of Caesalpinia sappan L. against oral carcinoma (KB) cells and osteosarcoma (HOS) cells were 9.0 microgram/ml and 10.9 microgram/ml, respectively. 2. The methanol extract of Caesalpinia sappan L. showed inhibitory effect of telomerase which is required for cancer cell immortality. Therefore, it seems that the anticancer effect of methanol extract of Caesalpinia sappan is at least partially due to telomerase inhibitory effect. 3. Five fraction samples were prepared according to its polarity and 88.7% of ingredient of total methanol extract was transferred to ethylacetate fraction. Thin layer chromatography analysis showed that dichloromethane fraction contained ingredient with relatively high polarity and ethylacetate fraction contained similar ingredient found in total methanol extract. 4. Anticancer effect was observed in n-hexane, dichloromethane, and ethylacetate fractions. The highest anticancer effect was found in dichloromethane fraction which had IC50 value of 4.4 and>4.0 microgram/ml against oral carcinoma (KB) cells and osteosarcoma (HOS) cells, respectively.
Caesalpinia* ; Cell Proliferation ; Chromatography, Thin Layer ; Inhibitory Concentration 50 ; Methanol ; Methylene Chloride ; Osteosarcoma* ; Telomerase