OBJECTIVETo analyze asbestos exposure level between 1984 and 2010 in a district of malignant mesothelioma with clustering incidence in Zhejiang Province, in order to improve the recognizing and early diagnosis of malignant mesothelioma, protect the health of workers.

METHODSMonitoring data of total asbestos dust concentration in the air of workplace from 1984 to 2010 in asbestos textile enterprises, family hand spinning operation, brake production, and asbestos board production in Zhejiang Province were collected in the local CDC. A total of 766 TWA copies of mass concentration were collected, and 1233 copies of MAC data. Asbestos mass concentration and fibre counting concentration of 29 points of family hand spinning operation were parallel determinated in the same time and the same sampling point. Raw asesbtos materials and dust composition of local asbestos processing corporations were collected and analyzed using X-ray diffraction method.

RESULTSRaw materials of asbestos used between 1984 and 2010 in this area were chrysotile from Sichuan, Qinghai, Xinjiang, Russia, Zimbabwe, and some were mixed with SiO2, CaCO3 and other impurities. Raw materials used in asbestos board production were blue asbestos. Dust concentration between 1960s and 1980s in asbestos processing plants far exceeded the national standard. After then the dust concentration decreased significantly, but still higher than the national standard. 95.2% of air dust concentrations in the workplaces of asbestos factories exceeded the standard, and dust concentrations of workplaces of raw material, spinning, weaving, carding and labor insurance were above 90% in which carding work had the highest median concentration. 37.9% of dust mass concentrations in hand spinning work exceeded the standard where textile machinery side had the highest value. Beating job in asbestos board manufacturing and grinding job in brake production had higher concentrations.

CONCLUSIONSMost of production technologies in asbestos processing industry exceed the standard level, indicating that the workers were at risk for malignant mesothelioma and other asbestos related diseases, which should draw high attention.

Asbestos ; analysis ; Asbestos, Crocidolite ; analysis ; Asbestos, Serpentine ; analysis ; China ; epidemiology ; Dust ; analysis ; Humans ; Lung Neoplasms ; epidemiology ; Mesothelioma ; epidemiology ; Occupational Diseases ; epidemiology ; Silicon Dioxide ; analysis ; Workplace

Asbestos is a fibrous silicate that was widely used because of its heat resistance properties. Asbestos exposure affects workers involved in mining or processing asbestos or those involved in the use of asbestos in the shipbuilding, construction, and textile- and insulation-manufacturing industries. There are three commonly available types of asbestos; chrysotile (white asbestos), amosite (brown asbestos), and crocidolite (blue asbestos). All three have been associated with cancerous and non-cancerous lung disease. Asbestos-related diseases includes benign pleural effusion, pleural plaques, diffuse pleural thickening (a non-malignant disease affecting the lung lining), rounded atelectasis, asbestosis (a scarring of the lung tissue caused by asbestos), mesothelioma and lung cancer. Mesothelioma is a malignant pleural or peritoneal tumor that rarely occurs in patients who have not been exposed to asbestos. The latency period of most asbestos-related disease is 10 years or longer, asbestos-related disease remains an important public health issue. The clinical diagnosis of asbestos related diseases should be based on a detailed interview of the patient and occupational data on asbestos exposure, signs and symptoms, radiological and lung physiological findings and selected cytological, histological and other laboratory studies. Radiological imaging plays a pivotal role in the diagnosis and management of asbestos-related disease.
Asbestos ; Asbestos, Amosite ; Asbestos, Crocidolite ; Asbestos, Serpentine ; Asbestosis ; Cicatrix ; Compensation and Redress ; Hot Temperature ; Humans ; Latency Period (Psychology) ; Lung ; Lung Diseases ; Lung Neoplasms ; Mesothelioma ; Mining ; Pleural Effusion ; Public Health ; Pulmonary Atelectasis ; Silicates ; Workers' Compensation

OBJECTIVE: To investigate the physical and chemical properties of pulp capping materials based on bioactive glass (BG). METHODS: Novel BG pulp capping materials were composed of powder and fluid. The powder was BG (82.36% SiO₂, 15.36% CaO, and 2.28% P₂O₅) synthesized by using the sol-gel method combined with template technology. Two kinds of fluid were provided: (1) phosphate buffer (PB) solution and (2) phosphate buffer solution with 1% sodium alginate (SA) addition. After mixing the powder and fluid, BG-PB and BG-PB-SA were prepared. Setting time and compressive strength of the BG pulp capping materials were tested by setting time loading system and mechanical testing machine. Statistical analysis was performed using the independent sample t-test, with the significance set at 0.05. pH meters was used to test the pH of the BG pulp capping materials and mineral trioxide aggregate (MTA). The sealing ability of the BG pulp capping materials and MTA was tested by methylene blue dye leakage model. Statistical analysis was performed using one-way ANOVA analysis and LSD multiple comparison, with the significance set at 0.05. RESULTS: (1) Setting time: the initial and final setting time of BG-PB were (7.2±0.3) min and (12.7±0.9) min, respectively. And the initial and final setting time of BG-PB-SA was (7.5±0.3) min and (13.6±1.6) min. There was no significant difference between BG-PB and BG-PB-SA groups (P>0.05). (2) Compressive strength: the compressive strength of BG-PB was (16.5±1.8) MPa at 1 day and (14.1±3.7) MPa at the end of 28 days. However, the compressive strength of BG-PB-SA was (26.6±6.3) MPa on day 1 and (21.6±5.6) MPa on day 28, which was significantly higher than that of BG-PB (P<0.05). (3) pH: the pH of BG pulp capping materials' bulk immersed in simulated body fluid (SBF) went up to 8.06, and the highest pH of MTA was 8.47. Significant difference was observed between the BG pulp capping materials and MTA (P<0.05). (4) Sealing ability: the optical density (D) in positive control group was significantly higher than ln BG-PB, BG-PB-SA and MTA groups (P<0.05). And BG-PB and BG-PB-SA showed the similar favorable sealing ability with MTA, and no significant difference was observed among the three groups (P>0.05). CONCLUSION The novel BG pulp capping materials showed good physical properties, especially BG's setting time was short; BG pulp capping materials are promising.
Aluminum Compounds ; Calcium Compounds ; Compressive Strength ; Dental Pulp Capping ; Glass ; Materials Testing ; Oxides ; Silicates ; Silicon Dioxide

The inhalation of crystalline silica results in the production of reactive oxygen species(ROS). Among these ROS, hydroxyl radical( OH) is believed to be the most reactive one. OH is generated in reaction between superoxide and hydrogen peroxide catalyzed by transition metal, especially iron. Therefore iron should be important in the bioactivity of crystalline silica. Desferrioxamine, a iron chelator, may be protective in silica-induced pulmonary reaction. To test this assumption we investigated the protective effect of desferrioxamine on lipid peroxidation of cell membrane, cytotoxicity, production of proinflammatory and chemotactic cytokine and fibroblast proliferation by crystalline silica in vitro model. The results were as follows: 1. Fenton activity of silica and asbestos was significantly higher than that of control. Fenton activity in crocidolite was higher than silica at the same dose. This result correlated with iron content of dust. Fenton activity of silica and crocidolite was decreased by preincubation of silica with desferrioxamine. 2. Silica induced a dose-dependent increase of MIDA concentration in lung epithelial cell lysate dose dependently. Marked decrease of MDA was observed in desferrioxaminetreated silica group compared with untreated group. 3. As concentration of stimulated silica, silica?induced cytotoxicity was increased. There was significant decrease of cytotoxicity in desferrioxamine?treated silica group compared with untreated group. 4. a-quartz augmented the production of TNF-a and IL-8 from A549 cell. While desferrioxa-mine suppressed the release of cytokines. 5. Supernatant of silica-cocultured A549 cell induced a significant proliferation of fibroblast, which desferrioxaime blocked this proliferation. From these result, we concluded that desferrioxamine has a protective effect on silica induced pulmonary reaction.
Asbestos ; Asbestos, Crocidolite ; Cell Membrane ; Crystallins ; Cytokines ; Deferoxamine* ; Dust ; Epithelial Cells ; Fibroblasts* ; Hydrogen Peroxide ; Inhalation ; Interleukin-8 ; Iron ; Lipid Peroxidation ; Lung ; Oxygen ; Silicon Dioxide ; Superoxides

Asbestosis is a chronic inflammatory disorder of lower respiratory tract in which alveolar wall are progressively thickened by a fibrotic process. Fibrotic process characterized by an expansion of fibroblast and collagenous extracellular matrix secreted from this fibroblast. Alveolar macrophage is believed to be a primary target cell and major participant in the evolution of lung fibrosis after asbestos inhalation. Alveolar macrophage are known to release a variety of substance that induce tissue damage and stimulate inflammatory cells and fibroblast. Macrophage also release a variety of metabolite of arachidonic acid. Of these, PGE(2) is known to suppress fibroblast proliferation. Asbestos may be a very effective stimulus for fibroblasts without triggering the relase of PGE(2). To assess the fibrogenic properties of asbestos according to kind and dosage of asbestos and the ability of PGE(2) to suppress the proliferation of fibroblast, alveolar macrophages cultured with crocidolite, amosite and chrysotile in presence or absence of PGE(2)10(-5)M. At 24 hours after alveolar macrophage cultured with various stimuli, the released fibronectin and TNF-alpha was measured. Viability of alveolar macrophages was observed and growth promoting activity of macrphage supernatant to fibroblasts was quantified. The results were as follows; 1. The viability of alveoair macrophages stimulated with asbestos fiber was markedly decreased compared with control group except chrysotile 10 microgram group. Crocidolite and amosite were more cytotoxic than chrysotile. 2. All of asbestos augmented fibronectin production in concentration dependent fashion. 3. There was a significant positive correlation between TNF-alpha production in supernatant and fiber concentration. 4. Supernatant from alveolar macrophages cultured with asbestos were inducible a significant increase in fibroblast proliferation. 5. Incubation of avieolar macrophages with asbestos in the presence of PGE(2) resulted in significant decrease of TNF-alpha production in supernant. 6. Supernatant from alveolar macrophages cultured with asbestos were inducible a: sig nificnat decrease in fibroblast proliferation when PGE(2) was added. The result of this study strongly suggested that crocidolite and amosite were more cytotoxic and fibrogenic and exogenous PGE(2) suppressed fibroblast proliferation following exposed to asbestos.
Animals ; Arachidonic Acid ; Asbestos* ; Asbestos, Amosite ; Asbestos, Crocidolite ; Asbestos, Serpentine ; Asbestosis ; Collagen ; Extracellular Matrix ; Fibroblasts* ; Fibronectins ; Fibrosis ; Inhalation ; Lung ; Macrophages ; Macrophages, Alveolar ; Rats* ; Respiratory System ; Tumor Necrosis Factor-alpha

OBJECTIVE: To examine the prophylactic potential of 3 orthodontic bonding adhesives: Fuji Ortho SC, Illuminate, and Resilience. METHODS: Thirty-six Wistar Wag rats were randomly divided into 4 groups consisting of 9 rats each. One of the groups received no treatment and was used as a control. In the other groups, individual bands coated with one of the 3 adhesives were cemented to the lower incisors. Enamel samples were obtained after 6 and 12 weeks and analyzed using scanning electron microscopy in combination with energy dispersive spectrometry. RESULTS: Six weeks after band cementation, no fluoride was found in the enamel of the lower incisors. After 12 weeks, there was no fluoride in the enamel of teeth coated with the Resilience composite. However, in the case of the Illuminate composite and the resin-modified glass ionomer Fuji Ortho SC cement, the depth of fluoride penetration reached 2 microm and 4.8 - 5.7 microm, respectively. CONCLUSIONS: Fluoride ions from orthodontic adhesives can be incorporated into the surface layer of the enamel. Orthodontists may apply orthodontic adhesives, such as the Fuji Ortho SC, to reduce the occurrence of caries during orthodontic treatment with fixed appliances.
Acrylic Resins ; Adhesives ; Aluminum Silicates ; Animals ; Cementation ; Dental Cements ; Dental Enamel ; Fluorides ; Glass ; Incisor ; Ions ; Microscopy, Electron, Scanning ; Orthodontics ; Rats ; Silicon Dioxide ; Tooth

OBJECTIVES: The purpose of the present in vitro study was to evaluate the biocompatibility of mineral trioxide aggregate (MTA) mixed with glass ionomer cement (GIC), and to compare it with that of MTA, GIC, IRM and SuperEBA. MATERIALS AND METHODS: Experimental groups were divided into 3 groups such as 1 : 1, 2 : 1, and 1 : 2 groups depending on the mixing ratios of MTA powder and GIC powder. Instead of distilled water, GIC liquid was mixed with the powder. This study was carried out using MG-63 cells derived from human osteosarcoma. They were incubated for 1 day on the surfaces of disc samples and examined by scanning electron microscopy. To evaluate the cytotoxicity of test materials quantitatively, XTT assay was used. The cells were exposed to the extracts and incubated. Cell viability was recorded by measuring the optical density of each test well in reference to controls. RESULTS: The SEM revealed that elongated, dense, and almost confluent cells were observed in the cultures of MTA mixed with GIC, MTA and GIC. On the contrary, cells on the surface of IRM or SuperEBA were round in shape. In XTT assay, cell viability of MTA mixed with GIC group was similar to that of MTA or GIC at all time points. IRM and SuperEBA showed significantly lower cell viability than other groups at all time points (p < 0.05). CONCLUSIONS: In this research MTA mixed with GIC showed similar cellular responses as MTA and GIC. It suggests that MTA mixed with GIC has good biocompatibility like MTA and GIC.
Acrylic Resins ; Aluminum Compounds ; Calcium Compounds ; Cell Survival ; Drug Combinations ; Glass ; Glass Ionomer Cements ; Glutamates ; Guanine ; Humans ; Microscopy, Electron, Scanning ; Osteosarcoma ; Oxides ; Silicates ; Silicon Dioxide ; Water ; Pemetrexed

OBJECTIVES: The purpose of this study was to determine the setting time, compressive strength, solubility, and pH of mineral trioxide aggregate (MTA) mixed with glass ionomer cement (GIC) and to compare these properties with those of MTA, GIC, IRM, and SuperEBA. MATERIALS AND METHODS: Setting time, compressive strength, and solubility were determined according to the ISO 9917 or 6876 method. The pH of the test materials was determined using a pH meter with specified electrode for solid specimen. RESULTS: The setting time of MTA mixed with GIC was significantly shorter than that of MTA. Compressive strength of MTA mixed with GIC was significantly lower than that of other materials at all time points for 7 days. Solubility of 1 : 1 and 2 : 1 specimen from MTA mixed with GIC was significantly higher than that of other materials. Solubility of 1 : 2 specimen was similar to that of MTA. The pH of MTA mixed with GIC was 2-4 immediately after mixing and increased to 5-7 after 1 day. CONCLUSIONS: The setting time of MTA mixed with GIC was improved compared with MTA. However, other properties such as compressive strength and pH proved to be inferior to those of MTA. To be clinically feasible, further investigation is necessary to find the proper mixing ratio in order to improve the drawbacks of MTA without impairing the pre-existing advantages and to assess the biocompatibility.
Acrylic Resins ; Aluminum Compounds ; Calcium Compounds ; Compressive Strength ; Drug Combinations ; Electrodes ; Glass ; Glass Ionomer Cements ; Glutamates ; Guanine ; Hydrogen-Ion Concentration ; Oxides ; Silicates ; Silicon Dioxide ; Solubility ; Pemetrexed

This study was carried out in order to determine in vitro biocompatibility of white mineral trioxide aggregate (MTA), and to compare it with that of the commonly used materials, i. e. calcium hydroxide liner (Dycal), glass ionomer cement (GIC), and Portland cement which has a similar composition of MTA. To assess the biocompatibility of each material, cytotoxicity was examined using MG-63 cells. The degree of cytotoxicity was evaluated by scanning electron microscopy (SEM) and a colorimetric method, based on reduction of the tetrazolium salt 2,3 bis {2methoxy 4nitro 5[(sulfenylamino) carbonyl] 2H tetrazolium hydroxide} (XTT) assay. The results of SEM revealed the cells in contact with GIC, MTA, and Portland cement at 1 and 3 days were apparently healthy. In contrast, cells in the presence of Dycal appeared rounded and detached. In XTT assay, the cellular activities of the cells incubated with all the test materials except Dycal were similar, which corresponded with the SEM observation. The present study supports the view that MTA is a very biocompatible root perforation repair material. It also suggests that cellular response of Portland cement and GIC are very similar to that of MTA.
Acrylic Resins ; Aluminum Compounds ; Calcium Compounds ; Calcium Hydroxide ; Drug Combinations ; Glass Ionomer Cements ; Glutamates ; Guanine ; Humans ; Hydroxides ; Microscopy, Electron, Scanning ; Minerals ; Oxides ; Silicates ; Silicon Dioxide ; Pemetrexed

Exposure to various particles and fibers can result in lung inflammation that may progress to fibrosis, even lung cancer for which there is no effective clinical treatment now. The mechanism involved in pulmonary injury has not been well defined ; however, most current evidence implicates a central role for alveolar macrophages (AM) in this process. Also apoptosis or programmed cell death is regarded as a mechanism which is related with the pulmonary fibrosis. We propose that the cytotoxic potential of various particles may be evaluated by measuring lactic dehydrogenase (LDH) from particle co-cultured supernatant and theses particles may induce the characteristics of apoptosis, DNA ladder. We analyzed rat AM culture media which was incubated for 3 days with the same concentration (10 ug/ml) of silica(Si), chrysotile(Ch), crocidolite(Cr), ceramic fiber(CF), rock wool(RW) and glass wool (GW). And each particles (50ug/cm(2)) was incubated with A549 (pneumocyte in tracheal epithelium) cell lines for 24 hours to confirm the DNA ladder. Additionally, silica induced apoptosis in vivo was confirmed by electromicroscopic observation. The results were as follows; 1. Silica, asbestos and man-made mineral fibers (MMMF) co-cultured with AM showed the increase of LDH significantly with the time interval of 24, 48, 72 hours except for ceramic fiber in 48 and 72 hours and crocidolite in 72 hours. 2. Silica, asbestos and man-made mineral fibers (CF, GF) showed the characteristics of apoptosis, DNA ladder, which was induced by incubating A549 cell with each particles for 24 hours in vitro 3. Apoptotic alveolar macrophage was observed the findings of zeiosis (membrane blebbing), condensation of nuclear chromosome and many vacuoles in cytoplasm, electomicroscopically.
Animals ; Apoptosis* ; Asbestos* ; Asbestos, Crocidolite ; Cell Death ; Cell Line ; Ceramics ; Culture Media ; Cytoplasm ; DNA ; Fibrosis ; Glass ; Lung Injury ; Lung Neoplasms ; Macrophages, Alveolar ; Mineral Fibers* ; Oxidoreductases ; Pneumonia ; Pulmonary Fibrosis ; Rats ; Silicon Dioxide* ; Vacuoles ; Wool