OBJECTIVETo compare the determination methods of fiber number concentration between China and WHO.

METHODSIndividual fiber samplings were conducted at a RCF manufacturing enterprise for 40 types of work. Flow rate was set as 2 L/min and lasted 2 to 4 hours. We used acetone-triacetin to prepare samples. The rules of two methods were used to count fibers for each sample respectively. The differences between the results of two methods were compared using the sign-rank test, and the correlation between the two methods' counting results were evaluated by the Spearsman rank correlation analysis.

RESULTSThe results of WHO counting rule were higher than those of Chinese counting rule for the same sample. The ratios of WHO method to Chinese method ranged from 1.88 to 3.70. Paired sign-rank test found the statistically significant differences of the results between the two methods (P<0.01). The rank correlation coefficient of the results by two rules counting ranged between 0.621 to 0.975, suggested positive correlation (P<0.01). The possible reasons of the difference between the two methods included the difference between the shapes of asbestos fiber and man-made mineral fiber, and counting rules of two methods.

CONCLUSIONThe results of WHO counting method is higher than those of Chinese counting method. High correlations between the results of the two methods were observed.

Asbestos ; analysis ; Chemistry Techniques, Analytical ; methods ; China ; Humans ; Mineral Fibers ; analysis ; Specimen Handling ; World Health Organization

Maximum Allowable Concentration ; Mineral Fibers ; analysis ; Occupational Exposure ; analysis

BACKGROUND: The host response to natural fibers results in granuloma formation in an effort to limit tissue destruction. Matrix metalloproteinases (MMPs) are important molecules in the inflammatory granulomatous or reparative reaction. Here, we studied the foreign body reaction that occurs following natural fibers implantation by investigating MMPs and tissue Inhibitor of MMPs (TIMPs) in an in vivo model. METHODS: Female Sprague-Dawley rats were treated with crocidolite fiber or fibrous talc via subcutaneous and intraperitoneal injections and immunohistochemistry was conducted to confirm the expression of MMPs and TIMP-2 in tissue sections. RESULTS: We identified that mineral fibers elicited granulomas. Fibrous talc or intraperitoneal injection resulted in larger granulomas and severe tissue destruction compared with the lesions induced by crocidolite or subcutaneous injection. The expression of MMPs was elevated while granulomatous lesions were formed. The relative levels of MMPs were lower in the talc injected or intraperitoneal route models than those of crocidolite injected or subcutaneous injection models during the entire experiment. CONCLUSIONS: These findings demonstrate that specific expression of MMPs/TIMP is inversely related to the grade of tissue destruction and suggest that expression of MMPs is required for promoting granuloma formation and limiting tissue destruction.
Animals ; Asbestos ; Asbestos, Crocidolite ; Female ; Foreign Bodies ; Foreign-Body Reaction ; Granuloma ; Humans ; Immunohistochemistry ; Injections, Intraperitoneal ; Injections, Subcutaneous ; Matrix Metalloproteinases ; Mineral Fibers ; Rats ; Rats, Sprague-Dawley ; Talc ; Tissue Inhibitor of Metalloproteinase-2

OBJECTIVETo study the cytotoxicity induced by chrysotile asbestos (CA), rock wool (RW) and wollastonite (WS).

METHODSV79 cells were divided into 4 groups. i.e. CA group, WS group, RW group and control group (200 microl PBS). The exposure concentration of dusts was 100 mg/L, The cell viability was detected by MTT and lactate dehydrogenase (LDH) activity assays. The technique of scanning electron microscopy was used to examine the change of V79 cells.

RESULTSSiO2 was main constituent for 3 kinds of dusts. In MTT assay, the cell viability of RW and WS groups was 64.8% and 65.7%, respectively, which were significantly higher than that (54.5%) of CA group (P < 0.01). In LDH assay, the LDH activity of RW and WS groups [(15.7 +/- 50.9), (12.3 +/- 3.7) U/L, respectively] was significantly lower than that [(20.2 +/- 0.9) U/L] of CA group (P < 0.05). In scanning electron microscopy examination, it was found that the two ends of V79 cells in CA group contained a great deal of fibers remaining bodies, but the V79 cell appearance in RW and WS groups was normal.

CONCLUSIONThe cytotoxicity induced by RW and WS is significantly lower than that induced by CA for V79 cell.

Animals ; Asbestos, Serpentine ; toxicity ; Calcium Compounds ; toxicity ; Cell Line ; drug effects ; Cricetinae ; Cytotoxins ; toxicity ; Lactate Dehydrogenases ; metabolism ; Mineral Fibers ; toxicity ; Silicates ; toxicity

Sepiolite--an inexpensive, resourceful, fibrous yet inoffensive mineral--made DNA transformation rapid, simple and efficient but the mechanism for DNA transformation was still unclear. Through RNA competition test, we proposed the different transforming mechanisms from the previous report. Meanwhile, we optimized the transforming method and could transfer a colony stored at 4 degrees C for a month with plasmid through sepiolite fibers. The cells could be transformed well without competent cells preparation or incubation process. In sum, this was a novel potential transforming method, which could be explored further if the chemical method and electroporation could not be used.
DNA, Bacterial ; chemistry ; genetics ; Electroporation ; methods ; Magnesium Silicates ; chemistry ; Mineral Fibers ; Nanofibers ; chemistry ; Transformation, Bacterial

Humans ; Mineral Fibers ; toxicity ; Respiratory Tract Neoplasms ; chemically induced

Apoptosis ; drug effects ; Asbestos ; toxicity ; Humans ; Mineral Fibers ; toxicity

Bronchi ; drug effects ; pathology ; Cell Line ; Cell Transformation, Neoplastic ; drug effects ; Epithelial Cells ; drug effects ; pathology ; Humans ; Mineral Fibers ; toxicity

OBJECTIVES: This study was designed to evaluate cytotoxicity of TAFMAG, which is a trade name of natural mineral fiber mined and produced in China. METHODS: The cytotoxicity of TAFMAG was evaluated by measuring iron content, lipid peroxidation, erythrocyte hemolysis, and cytotoxicity in vitro. These results were compared with the data of chrystotile and wollastonite as a positive and negative control, respectively. RESULTS: There was significant increase of Fenton activity in TAFMAG and chrysotile with dose-response pattern. The iron chelating agent, desferrioxamine, significantly decreased Fenton activity of the particulates except wollastonite. TAFMAG and chrysotile fibers significantly increased malondialdehyde concentration from lipid peroxidation of the red blood cell membrane. In erythrocyte hemolysis test, TAFMAG & chrysotile had stronger effect on erythrocyte hemolysis than wollastonite with the concentration of 1,000g/ml. Furthermore, TAFMAG was more hemolytic than chrysotile with the concentration of 5.000 g/ml. There was a significant cytotoxic effect in TAFMAG and chrysotile on RAW cell compared with wollastonite. CONCLUSIONS: In vitro study suggested that TAFMAG may have a similar health hazard as usual asbestos.
Asbestos ; Asbestos, Serpentine ; China ; Deferoxamine ; Erythrocytes ; Hemolysis ; Iron ; Lipid Peroxidation ; Malondialdehyde ; Membranes ; Mineral Fibers

This study was carried out to evaluate the cytotoxicity of rock wool fibers(RWFs) such as cell division disturbance, chromosomal and DNA damage, and mutagenicity using cultured cells. RWFs were the man made mineral fibers. In order to find the correlation between the cytotoxicity of RWFs and the phagocytic capacity of cells, the phagocytic processes were observed using scanning electron microscope. Cell division disturbance by RWFs was evaluated by the formation of multinucleated giant cells. The chromosomal damage was evaluated by the micronucleus formation. For the evaluation of oxidative DNA damage, 8-hydroxy-2'-deoxyguanosine (8-OH-dG) formation was measured utilizing calf thymus DNA. Mutagenicity was determined by the point mutation of HGPRT and the effect of RWFs on cell transformation was also observed. 1. Compared with the results of chrysotile, RWFs were no or little effect on the cell growth according to the results done by the tests of cell proliferation inhibition and relative plating efficiency. 2. The frequency of multinucleated giant cell formation was increased by the treatment of RWFs and it was dose-dependent. However, the effect of RWFs was weaker than that of chrysotile. 3. The number of micronuclei formed in the RWFs treated cells was between those of cells treated with chrysotile and those of untreated cells. 4. The 2 fold increase in the formation of 8-OH-dG in calf thymus DNA was observed in the cells treated with RWFs in the presence of H2O2. On the other hand, chrysotile had no effect on the 8-OH-dG formation. 5. RWFs had no effect on the HGPRT point mutation and cell transformation. These results showed that RWFs could induce chromosomal damage, cell division disturbance and oxidative DNA damage in the RWFs treated cells.
Asbestos, Serpentine ; Cell Division ; Cell Proliferation ; Cells, Cultured ; DNA ; DNA Damage ; Giant Cells ; Hand ; Hypoxanthine Phosphoribosyltransferase ; Mineral Fibers ; Point Mutation ; Thymus Gland ; Wool*