Effect of silicon dioxide exposure on airway surface microenvironment and NEK7/NLPR3 inflammasome in rats / 预防医学

Objective@#To examine the effect of SiO2 exposure on the airway surface microenvironment and NIMA-related kinase 7 (NEK7)/nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) inflammasome in rats.@*Methods@#Twenty-four specific pathogen-free male rats of the SD strain were randomly divided into the control group and the model group, of 12 rats in each group. Rats in the model group were given SiO2 suspensions through disposable tracheal intubation perfusion to model silicosis in rats, while rats in the control group was perfused with the same amount of physiological saline. The pH value and glucose level were measured in the rat bronchoalveolar lavage fluid (BALF) 14 and 28 days after modeling. Lung tissues were stained with HE and Masson and the distribution of inflammatory cells and the deposition of pulmonary interstitial collagens were observed in lung tissues under a light microscope. The expression of transforming growth factor β1 (TGF-β1), collagen type Ⅰ(ColⅠ), collagen type Ⅲ (Col Ⅲ), interleukin-1β (IL-1β), NLRP3, N-terminal domain of Gasdermin D (GSDMD-NT), caspase-1, and NEK7 was quantified in lung specimens using immunohistochemistry.@*Results@# Lower pH values were measured in rat BALF in the model group than in the control group 14 [(6.38±0.05) vs. (6.68±0.08), P<0.05] and 28 days after modeling [(6.63±0.14) vs. (6.86±0.05), P<0.05], while higher glucose levels were seen in the model group than in the control group 14 [(0.39±0.06) vs. (0.31±0.04) mg/dL, P<0.05] and 28 days after modeling [(0.39±0.08) vs. (0.31±0.06) mg/dL, P<0.05]. HE and Masson staining showed mild to moderate alveolitis and pulmonary fibrosis in rats 14 days post-exposure to SiO2, and showed moderate to severe alveolitis and pulmonary fibrosis 28 days post-exposure. Immunohistochemistry detected higher TGF-β1, ColⅠ, Col Ⅲ, IL-1β, NLRP3, GSDMD-NT, caspase-1 and NEK7 expression in rat lung tissues in the model group than in the control group (all P<0.05). @*Conclusions@#SiO2 exposure may cause changes in rat airway surface microenvironment, including BALF acidification and elevated glucose. Pyroptosis induced by activation of NEK7-associated NLRP3 inflammasome may be an important mechanism of pulmonary fibrosis caused by silicosis.

Effects of fiber surface deposited with silicon dioxide films on properties of fiber-reinforced composites / 口腔医学

Objective@#To investigate the effects of fiber surface deposited with silicon dioxide films by atomic layer deposition on properties of dental fiber-reinforced composites.@*Methods @#SiO2 films were deposited on the surface of quartz fiber by atomic layer deposition(ALD). Then the quartz fiber was used to manufacture fiber resin composites, which were divided into four groups: A(no soaking agent removal), B(soaking agent removed), C(soaking agent removed and silanization), and D(soaking agent removed, 600 ALD cycles performed and then silanization). Scanning electron microscopy, water contact angle test, hygroscopicity test, CCK8 test and three-point bending test were used to investigate the properties of fiber resin composites.@*Results@#The surface morphology of the quartz fiber treated by ALD was smooth and had no obvious change compared with that before treatment. Moreover, the quartz fiber showed hydrophobicity after silanization. The results of three-point bending test revealed that the mechanical properties of fiber-resin composites modified by ALD were significantly improved(P<0.05). When viewed by scanning electron microscopy, a good interfacial bonding could be seen between quartz fibers and the resin matrix in Group D. In addition, it was found that Group D had low absorbability, low solubility and good biocompatibility. @*Conclusion@#It is shown that deposition of SiO2 films on the quartz fiber by ALD can significantly enhance the mechanical properties of fiber-reinforced composites.

Cleansing effect of NO sustained-release silica nanoparticles on endoscopic biofilm and its clinical application / 中华消化内镜杂志

Objective:To explore the cleansing effect of Nitric Oxide (NO) sustained-release silica nanoparticles (short for NO sustained-release agent) on endoscopic biofilm and its clinical application.Methods:A total of 160 clinical endoscopes were randomly divided into two groups: the cleansing agent group (80 pieces, disinfected with cleansing agents), NO group (80 pieces, disinfected with NO sustained-release agent). A biofilm model of Pseudomonas aeruginosa was constructed and used as the control for phosphate buffered solution (PBS) treatment. A biofilm model of Pseudomonas aeruginosa on the surface of endoscopic lumen was built first in vitro. Scanning electron microscopy was then used to observe the microstructure of biofilm after treatment with NO sustained-release agent. Viable counting method was used to evaluate the cleansing effect of NO sustained-release agent on biofilm. Finally, at the clinical level, the actual disinfection effect of NO sustained-release agent on clinical endoscopy was evaluated by detecting the protein residues, viable counting and adenosine triphosphate (ATP) biofluorescence detection. Results:The scanning electron microscopy showed that the biofilm was intact in the model group, but scattered bacteria were observed on the biofilm surface in the NO group and the detergent group. Compared with the model group [(4.86±2.67)×10 6(colony-forming units, CFU)/mL], the standard CFUs of the NO group [(1.37±0.61)×10 4CFU/mL] and the detergent group [(1.31±0.21)×10 5CFU/mL] were significantly lower (detergent group VS model group, P=0.009; NO group VS model group, P=0.008), and there was significant difference between the detergent group and the model group ( t=9.53, P=0.000 6). The levels of residual proteins in the endoscopic lumens before and after the treatment were 8.03±1.47 mg/mL and 0.50±0.37 mg/mL in the NO group, 8.01±1.51 mg/mL and 0.91±0.52 mg/mL in the detergent group with significant difference ( P<0.01), and the reduction effect of the NO group was more significant. The disinfection of NO group and cleaning agent group was within the qualifying range, but the ATP bioluminescence value, protein residue and colony count of NO group (78.56±42.59 RLU, 0.50±0.37 mg/mL, 7.55±4.56 CFU) were significantly lower than those of detergent agent group (120.80±54.00 RLU,0.91±0.52 mg/mL,11.50±4.75 CFU, P<0.01). Conclusion:NO sustained-release agent can effectively clear endoscopic biofilm and further improve the disinfection effect on endoscopes, which may be of great significance for improving the effects on treatment and prognosis of patients.

Effect of miR-204 targeted regulation of DVL3 gene in silica-induced mouse lung epithelial cells / 中华劳动卫生职业病杂志

Objective: To construct a recombinant lentiviral vector for mouse miR-204 overexpression, and to verify the targeted regulation of miR-204 and DVL3 in silica (SiO(2)) -induced mouse lung epithelial cells (MLE-12 cells) . Methods: In October 2019, the pre-miR-204 gene was amplified from the mouse genome by the polymerase chain reaction (PCR) method. After sequencing, the amplified product was cloned into the pLenti-CMV-EGFP lentiviral vector. The positive clones were identified by PCR screening and sequencing. The miR-204 overexpressed lentiviral vector was transfected into 293T cells, and lentiviral packaging and titer determination were performed. The experiment was divided into SiO(2) control group, virus control group, and miR-204 virus group, and the expressions of miR-204 and DVL3 gene were detected by real-time PCR. Results: The miR-204 lentiviral expression vector Lv-miR-204-5p was constructed and identified correctly by PCR and sequencing, and a virus dilution with a titer of 9.57×10(8) IU/ml was obtained. The results of real-time PCR showed that the expression of miR-204 in MLE-12 cells of the miR-204 virus group was higher than that of SiO(2) control group and virus control group, and the expression of DVL3 gene was lower than that of SiO(2) control group and virus control group, the differences were statistically significant (P<0.05) . Conclusion: Overexpression of miR-204 by lentiviral vector may inhibit the expression of DVL3 gene in silica-induced mouse lung epithelial cells.

Effects of silicon dioxide exposure on lipid deposition and PI3K/AKT/mTOR signaling pathway in MLE-12 cells / 环境与职业医学

Background Lipid metabolism imbalance is tightly linked to the development and progression of multiple diseases. The phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling pathway is important for the regulation of lipid metabolism. However, whether silicosis is associated with lipid metabolic abnormalities has yet to be explored. Objective To observe the changes of lipid deposition, cholesterol, and phosphorylated proteins of PI3K/AKT/mTOR pathway in silicon dioxide (SiO2)-induced MLE-12 cells and to explore potential mechanism of lipid composition regulated though the pathway. Methods (1) MLE-12 cells were stimulated with 50 mg·L−1 SiO2 suspension, and divided into fourgroups: a control group and three SiO2 groups (12, 24, and 48 h of stimulation). (2) Cellproliferation was detected to determine an optimal dose of LY294002, an inhibitor of PI3K protein. LY294002 at 5 μmol·L−1 was used for further study, in which MLE-12 cells cultured for 48 h were divided into four groups: a control group; a 50 mg·L−1 SiO2 suspension stimulation group; a 50 mg·L−1 SiO2 suspension and 5 μmol·L−1 LY294002 treatment group; a 5 μmol·L−1 LY294002 treatment group. Total cholesterol (TC), free cholesterol (FC), cholesterol ester (CE; total cholesterol minus free cholesterol), and triglycerides (TG) were measured with enzyme assay kits. Lipid deposition was observed using Oil Red O staining. The expressions of p-PI3K, p-AKT, and p-mTOR proteins were detected by Western blotting. Results (1) The contents of TC, FC, and CE in the 50 mg·L−1 SiO2-induced MLE-12 cells were increased compared to those of the control group in a time-dependent manner by trend analysis, and the increment at 24 and 48 h were significant. By 48 h, the contents of cholesterol indicators were all elevated: TC from (2.242±0.181) mg·g−1 to (5.148±0.544) mg·g−1, FC from (1.923±0.158) mg·g−1 to (4.168±0.433) mg·g−1, and CE from (0.318±0.067) mg·g−1 to (0.978±0.134) mg·g−1, compared with the control group (P<0.01). The changes of TG were not significant (P>0.05). The SiO2 suspension induced orange-red particle deposition in the MLE-12 cells, especially at 48 h (P<0.01). The protein expression levels of p-PI3K, p-AKT, and p-mTOR in SiO2-stimulated MLE-12 cells were higher than those of the control groups with the prolongation of stimulation time, which peaked at 48 h (P<0.01). (2) The contents of TC, FC, and CE in MLE-12 cells of the SiO2 + LY294002 group were decreased, comparing to those of the SiO2 stimulation only group (P<0.01), companied with less orange-red lipid deposition, and suppressed protein expression levels of p-PI3K, p-AKT, and p-mTOR (P<0.01). Conclusion SiO2 could induce increases of cholesterol and lipid deposition through activation of PI3K/AKT/mTOR signaling pathway in MLE-12 cells.

The role of TSG-6 in inhibiting the secretion of IL-1β by bone-marrow-derived macrophages / 中国职业医学

@#Objective To investigate the role of tumor necrosis factor alpha stimulated gene/inducible protein 6（TSG-6）on free silica（SiO2 ）-induced secretion of pro-inflammatory cytokine interleukin（IL）-1β by bone-marrow-derived macrophages （BMDMs）. Methods i）BMDMs isolated from bone marrow were divided into eight groups：the control group was untreated； lipopolysaccharide （LPS） group was stimulated by LPS with a concentration of 50 µg/L；The TSG-6 control group was stimulated by 100 µg/L of recombinant mouse TSG-6. SiO2 model group was pre-stimulated with LPS for four hours，and then stimulated with SiO2 suspension at a final concentration of 250 mg/L；Different dose of TSG-6 groups were firstly treated with above concentrations of LPS and SiO2 suspension，then 10，20，50 and 100 µg/L of recombinant mouse TSG-6 were added respectively；After 16 hours of culture，the cells were collected and the level of IL-1β in BMDMs supernatant was detected by enzyme-linked immunosorbent assay（ELISA）to screen optimal concentration of TSG-6. ii）The cells of the control group，LPS group，SiO2 model group，TSG-6 optimal concentration group and TSG-6 control group were collected. The expression of IL-1β and components of its related pathways in BMDMs was detected by Western blot，including IL-1β，pro-IL-1β，caspase-1，pro dcaspase-1，asc type amino acid transport and NOD-like receptor protein 3（NLRP3）. Results i）Compared with the control group，the expression of IL-1β in SiO2 model group was increased significantly（P<0.01）. Compared with SiO2 model group，the expression of IL-1β in 20，50，100 µg/L dose of TSG-6 groups were decreased significantly（all P<0.01），and the optimal concentration of TSG-6 was found to be 100 µg/L. ii）Compared with the control group and LPS group，the relative expression levels of IL-1β，caspase-1 and NLRP3 in SiO2 model group were increased significantly （all P<0.05）. Compared with SiO2 model group，the expression levels of IL-1β、caspase-1 and NLRP3 were decreased in 100 µg/L TSG-6 group（all P<0.05）. Conclusion TSG-6 could inhibit BMDMs to secret pro-inflammatory cytokine IL-1β by down-regulating the expression of NLRP3 and caspase-1.

Evaluation of biofilm formation on acrylic resin surfaces coated with silicon dioxide: an in situ study

Abstract Biofilm on acrylic resin dental prostheses may cause gingival inflammation. This study evaluated the influence of a silicon dioxide coating layer applied onto acrylic resin on the adhesion of microorganisms. Blocks (5 x 5 x 3 mm) of acrylic resin were evaluated for surface roughness and divided into two groups: control (CG) and coated with silicon dioxide (LG group). The specimens were evaluated by scanning electron microscopy (n = 1) and by contact angle analysis (n = 3). For the in situ study, 20 volunteers wore acrylic palatal devices containing three samples from each group (n = 60) for 2 days. The biofilm formed was quantified by metabolic activity and total biomass using the crystal violet assay. The results were subjected to Bartlett's normality test and Gamma model with random effect for the response variable (α = 5%). The mean contact angle of the coated group was significantly lower than that of the uncoated group (p < 0.05). The metabolic activity of microorganisms in the biofilm on the blocks treated with coating was significantly lower than that of control blocks (p = 0.02). Regarding the amount of extracellular matrix produced by the microorganisms, there was no difference between the CG and LG group (p = 0.05). The application of a silicon dioxide coating on acrylic resin reduced the activity of the polymicrobial biofilm formed in situ. This coating may be advantageous for patients with conventional complete dentures or implants made of acrylic resin and who have motor difficulties that prevent them from cleaning their prostheses properly.

The value of acidic mammalian chitinase in early diagnosis of occupational pneumoconiosis / 中国职业医学

OBJECTIVE: To observe the expression of acidic mammalian chitinase(AMCase) in lung tissue of silicosis model rats, and bronchoalveolar lavage fluid(BALF) and serum of patients with occupational pneumoconiosis, and to evaluate the value of AMCase in the early diagnosis of pneumoconiosis. METHODS: i) The specific pathogen free adult male Wistar rats were randomly divided into control group and model group, with 15 rats in each group. The rats in the silicosis model group was exposed to free silica dust with a concentration of 2 000.0 mg/m~3 by dynamic inhalation for three hours a day, while the rats in control group were not exposed to dust. Five rats in the two groups were sacrificed at 4, 12 and 24 weeks after dust exposure. ii) By random number table method, a total of 191 patients with occupational pneumoconiosis who received large capacity lung lavage were selected as the pneumoconiosis group, 12 dust-exposed workers who received large capacity lung lavage were selected as the dust control group, and 200 healthy coal miners exposed to dust were selected as healthy control group. iii) Western blotting was used to detect the relative protein expression of AMCase, type Ⅰ collagen(COLⅠ), α-smooth muscle actin(α-SMA) in lung tissues of the rats and the relative protein expression of AMCase in human BALF. Enzyme linked immunosorbent assay was used to detect the level of AMCase protein in human serum. Receiver operating characteristic(ROC) curve was used to evaluate the value of AMCase protein level in human serum for early diagnosis of pneumoconiosis. RESULTS: The relative expression of AMCase, COLⅠand α-SMA protein in lung tissue of rats in the silicosis model group were higher than that of control group(all P<0.01). The relative expression of AMCase protein in BALF of pneumoconiosis group and pneumoconiosis stage Ⅰ, Ⅱ and Ⅲ subgroups were higher than that of dust control group(all P<0.05). The level of AMCase protein in serum of pneumoconiosis group and pneumoconiosis stage Ⅰ, Ⅱ and Ⅲ subgroups were higher than that of healthy control group(all P<0.05). The results of ROC curve analysis showed that the area under ROC curve was 0.78(95% confidence interval: 0.74-0.82).When the cut-off value of serum AMCase protein level was 466.0 ng/L, the sensitivity was 73.8%, and the specificity was 72.6%. CONCLUSION: AMCase protein in human serum has value for early diagnosis of pneumoconiosis and it could be a potential biomarker for early diagnosis of pneumoconiosis.

Ginseng ameliorates pulmonary toxicity induced by silicon dioxide nanoparticles in rats

Objective: To investigate the protective and therapeutic role of ginseng against silicon dioxide nanoparticles (SiO

Research advances on silica dust induced-autoimmune diseases and its mechanism / 中国职业医学

Silica dust is one of the main occupational hazards in various industries. In addition to causing occupational silicosis, silica dust can also stimulate innate and acquired immunity and induce autoimmune diseases(AID) such as systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis, and antineutrophil cytoplasmic antibody(ANCA)-associated vasculitis. Silica dust exposure can induce changes in the levels of autoantibodies in vivo, such as rheumatoid factor, antinuclear antibody, ANCA, anti-centromere antibody, anti-topoisomerase Ⅰ antibody, anti-desmoglein antibody, anti-centromere antigens-B antibody, anti-carbamylated protein antibody, anti-smooth muscle antibody and anti-glomerular basement membrane antibody. At present, the mechanism of autoimmune disorders induced by silica dust has not yet been fully elucidated. The current research suggests that it is related to cell apoptosis of alveolar macrophages, the disorder of the Fas/Fas ligand system, the imbalance of T cell proportion, and the dysregulation of T helper cell(Th) 1 and Th2 type cytokines homeostasis. Understanding the pathogenesis of autoimmune disorders induced by silica dust and exploring possible therapeutic targets will provide new ideas for the treatment of silicosis.

Effect of Silicon dioxide coating of acrylic resin surfaces on Candida albicans adhesion

Abstract Acrylic resin has been used in the manufacture of prostheses, however, in the oral cavity, this material starts to retain microorganisms capable of causing gingival inflammation due its porosities. The aim of this study was to evaluate the influence of the use of silicon dioxide as a coating layer applied onto acrylic resin, on the adhesion of Candida albicans (Ca). After the incubation period in Sabouraud Dextrose Broth, a total of 1 ml of the Ca suspension was added to plate wells, each well containing a specimen of acrylic resin. The adhesion ability of Ca on acrylic resin was determined by counting colonies. Three groups (n = 6) of acrylic resin were assessed: with polishing (RP); without polishing (RW); with polishing and coating layer of silicon dioxide (RPC). Ca deposited on the surface of the acrylic resin was also observed using Scanning Electron Microscopy (SEM). Statistical assessment by Kruskal-Wallis and Student-Newman-Keuls Method were done (α = 2%). There was significant difference among the groups. The RPC group showed the lowest growth, with an average of 5.59 Log CFU/cm 2 ; there was a statistically significant difference in relation to group RW, which presented a growth of 6.07 Log CFU/cm 2 and to group RP with 5.91 Log CFU/cm 2 (p < 000.1). SEM images demonstrated that in the RP and RPC group, the surface of the resin had greater regularity, and smaller number of microorganisms. The application of silicon dioxide coating on acrylic resin appears to be a promising alternative, and its use can help in reducing the adhesion of Ca in prostheses.

Effect of nilotinib on silicon dioxide-induced proliferation and collagen synthesis in HFL-1 cells / 中国职业医学

OBJECTIVE: To observe the effects of nilotinib on silicon dioxide(SiO_2)-induced cell proliferation and collagen synthesis in human fetal lung fibroblast-1(HFL-1) cells and to explore the related mechanism. METHODS: ⅰ) HFL-1 cells were induced with different doses of SiO_2 suspension(0, 5,10, 25, 50 and 100 mg/L) for 24.0 hours. The expression of transforming growth factor-β1(TGF-β1), C-Abl, and platelet-derived growth factor receptor(PDGFR) was detected by Western blot, and the dose of SiO_2 in subsequent experiments was screened. ⅱ) HFL-1 cells were randomly divided into 6 groups: 1) the control group: no treatment; 2) the solvent control group: cells were treated with 0.10% dimethyl sulfoxide; 3) the SiO_2 stimulation group: cells were induced with SiO_2 suspension at a dose of 50 mg/L for 24.0 hours; 4)-6) the nilotinib groups: cells were induced with SiO_2 suspension at a dose of 50 mg/L for 24.0 hours and treated with nilotinib at the concentration of 5, 10, or 15 mmol/L for 24.0 hours. Cell proliferation was detected by MTS assay. The TGF-β1 protein secreted by cells was measured using enzyme linked immunosorbent assay. The expression of TGF-β1, C-Abl, platelet derived growth factor(PDGF), PDGFR and collagen typeⅠproteins was measured by Western blot. RESULTS: ⅰ) The dose of the SiO_2 in the experiments was set to 50 mg/L. ⅱ) The cell proliferation rate of HFL-1 cells in the SiO_2 stimulation group and the 3 nilotinib groups was higher than that in control group and solvent control group(P<0.05). The proliferation rates of HFL-1 cells in 10 and 15 mmol/L nilotinib groups were lower than that in SiO_2 stimulation group(P<0.05). The level of TGF-β1 and the protein relative expression levels of TGF-β1, collagen typeⅠ, C-Abl, PDGFR and PDGF in HFL-1 cells of SiO_2 stimulation group were higher than those in control group and solvent control group(P<0.05). The above indexes of HFL-1 cells in 15 mmol/L nilotinib group were lower than that in SiO_2 stimulation group(P<0.05); the above indexes of HFL-1 cells in 5 mmol/L nilotinib group were not significantly different from those in SiO_2 stimulation group(P>0.05). The level of TGF-β1 and the relative expression level of C-Abl protein in HFL-1 cells of 10 mmol/L nilotinib group were lower than those in SiO_2 stimulation group(P<0.05). CONCLUSION: Nilotinib can inhibit the proliferation of HFL-1 cells and reduce the expression of collagen typeⅠprotein induced by SiO_2. This process may be achieved by inhibiting tyrosine kinase-mediated signaling pathway.

CT imaging analysis of artificial stone?agglomerated quartz associated silicosis / 中华放射学杂志

Objective To explore the CT imaging features of artificial stone?agglomerated quartz associated silicosis. Methods A total of 37 cases confirmed with artificial stone?agglomerated quartz associated silicosis from December 2016 to August 2018 and 38 cases confirmed with traditional classical silicosis at the same period were retrospectively reviewed.The clinical characteristics(including gender, age and working age)and the imaging features(including the nodule features, ground glass opacity, merging features, consolidation, secondary changes, etc.)of the two groups were recorded. The variables including the imaging findings between the two groups were analyzed by Fisher exact test. Results Of all the cases, there were bilateral diffuse small nodules which distributed with upper?zone predominance. Small nodules can merge together and form mass shadow. The complications such as lymphadenopathy, calcification, emphysema/pneumatocele, pulmonary interstitial fibrosis could also be found. Among the various imaging features, the presence of ground glass opacity, small nodules merging together in the subpleural zones, consolidation, pulmonary interstitial fibrosis, pneumothorax were found in 28,16,18,17,5 cases, respectively in artificial stone?agglomerated quartz associated silicosis group, and 2, 4, 4, 4, 0 cases, respectively in the traditional classical silicosis group. The percentages of these above signs were higher in the artificial stone?agglomerated quartz associated silicosis group than the traditional classical silicosis group, and the differences were statistically significant(P<0.01). The artificial stone?agglomerated quartz associated silicosis group had 3 cases with mediastinal lymph node enlargement with calcification, while the traditional classical silicosis group had 12 cases. This sign showed a lower significantly incidence in the artificial stone?agglomerated quartz associated silicosis group than the traditional classical silicosis group(P<0.01). Conclusion The characteristic changes of CT imaging features in artificial stone?agglomerated quartz associated silicosis are small nodules with the background of ground glass opacity, the nodules merging together under subpleural zones, consolidation, mediastinal lymph node enlargement with less calcification and complicated with pulmonary interstitial fibrosis and pneumothorax.

Comparison between pyrophosphate method and infrared spectrophotometry for determination of silicon dioxide content in dust / 中华劳动卫生职业病杂志

Objective@#To discuss the difference between pyrophosphoric acid method and infrared spectrophotometry for the determination of silica content in dust.@*Methods@#The content of silica in the laboratory comparison samples organized by CDC Occupational Health Institute in China in 2018, and purchased quality control samples were determined by pyrophosphate method. Meanwhile, the samples were qualitatively and quantitatively analyzed by infrared spectrophotometry, and the results obtained by the two methods were compared.@*Results@#Four samples (062C1、062C2、GDOHZKTG012-1、GDOHZKTG012-2) were detected by pyrophosphate method and infrared spectrophotometry. The results of pyrophosphate method were 55.49%, 5.24%, 4.90% and 54.72%, respectively. The results of infrared spectrophotometry were 0.91%, 1.87%, 1.29% and 1.16% respectively.@*Conclusion@#The content of silica in dust determined by pyrophosphate method is higher than that by infrared spectrophotometry.

CT imaging analysis of artificial stone-agglomerated quartz associated silicosis / 中华放射学杂志

Objective@#To explore the CT imaging features of artificial stone-agglomerated quartz associated silicosis.@*Methods@#A total of 37 cases confirmed with artificial stone-agglomerated quartz associated silicosis from December 2016 to August 2018 and 38 cases confirmed with traditional classical silicosis at the same period were retrospectively reviewed.The clinical characteristics (including gender, age and working age)and the imaging features (including the nodule features, ground glass opacity, merging features, consolidation, secondary changes, etc.) of the two groups were recorded. The variables including the imaging findings between the two groups were analyzed by Fisher exact test.@*Results@#Of all the cases, there were bilateral diffuse small nodules which distributed with upper-zone predominance. Small nodules can merge together and form mass shadow. The complications such as lymphadenopathy, calcification, emphysema/pneumatocele, pulmonary interstitial fibrosis could also be found. Among the various imaging features, the presence of ground glass opacity, small nodules merging together in the subpleural zones, consolidation, pulmonary interstitial fibrosis, pneumothorax were found in 28,16,18,17,5 cases, respectively in artificial stone-agglomerated quartz associated silicosis group, and 2,4,4,4,0 cases, respectively in the traditional classical silicosis group. The percentages of these above signs were higher in the artificial stone-agglomerated quartz associated silicosis group than the traditional classical silicosis group, and the differences were statistically significant (P<0.01). The artificial stone-agglomerated quartz associated silicosis group had 3 cases with mediastinal lymph node enlargement with calcification, while the traditional classical silicosis group had 12 cases. This sign showed a lower significantly incidence in the artificial stone-agglomerated quartz associated silicosis group than the traditional classical silicosis group (P<0.01).@*Conclusion@#The characteristic changes of CT imaging features in artificial stone-agglomerated quartz associated silicosis are small nodules with the background of ground glass opacity, the nodules merging together under subpleural zones, consolidation, mediastinal lymph node enlargement with less calcification and complicated with pulmonary interstitial fibrosis and pneumothorax.

The Change in Coloration of Aluminum Silicate Hydrate with Silicon Dioxide to Bright Blue when Cinnamon Bark and Atractylodes Rhizome are Combined / 日本東洋医学雑誌

The change in color tone of crude drugs during storage of decoctions is one of the factors leading to poor drug compliance of decoctions. We experienced a case of a decoction including Aluminum Silicate Hydrate with Silicon Dioxide (Kasseki) turned into bright blue color after it was combined with goreisan. We therefore examined to find out possible causative crude drugs using an airtight container and performed a component analysis by the TLC. As a result, we found the following: Kasseki under the coexistence of Cinnamon Bark (C. Bark) and Atractylodes Rhizome (A. Rhizome) turned into a bright blue color in several hours. In this coloration, aluminum silicate hydrate, cinnamaldehyde and atractylon, which derive from these 3 crude drugs, were involved. This coloration change of Kasseki under coexistence of C. Bark and A. Rhizome was a vivid and sharp reaction generated in several hours. From the perspective of maintaining medication compliance, it is important to provide a full explanation to patients about the change in coloration of Kasseki, when decocting crude drugs that contain C. Bark, A. Rhizome, and Kasseki. To avoid coloration, it is considered useful to put Kasseki in a separate sachet, isolated from other crude drugs in storage, and to mix in Kasseki just before decocting.

Effect of nano-SiO_2 on the survival and PARP-1 expression in 16HBE cells / 中国职业医学

OBJECTIVE: To explore the effects of nano-silicon dioxide( SiO_2) on the survival and poly( ADP-ribose)polymerase-1( PARP-1) expression in human bronchial epithelial cells( 16 HBE cells). METHODS: i) The 16 HBE cells were treated with nano-SiO_2 at concentrations ranging from 0 to 100 mg/L for 24. 0 hours,and CCK-8 assay was used to examine cell viability. ii) The 16 HBE cells were divided into 6 groups: solvent control group( equal volume solvent treatment),micro-SiO_2 control group( treated with 20 mg/L micro-SiO_2),5,10,and 20 mg/L nano-SiO_2 groups( treated with the corresponding final dose of nano-SiO_2),and curcumin group. The curcumin group was given pretreatment with curcumin at a final concentration of 10 μmol/L for 2. 0 hours followed by treatment with a final concentration of 20 mg/L of nano-SiO_2. Cells in each group were harvested at time points of 4. 0,12. 0 and 24. 0 hours after treatment. The relative expression of PARP-1 mRNA and protein in 16 HBE cells was detected by quantitative real-time polymerase chain reaction and Western blotting respectively. RESULTS: i) The survival of 16 HBE cells decreased with increasing nano-SiO_2 treatment dose,showing a dose-effect relationship( P < 0. 01). ii) The expression of PARP-1 mRNA and protein in 16 HBE cells were dose-dependently decreased after nano-SiO_2 stimulation at the 12. 0 and 24. 0 hours time points( P < 0. 01). The expression of PARP-1 mRNA and protein in 5,10,and 20 mg/L nano-SiO_2 groups decreased at the above mentioned time points( P < 0. 05),compared with the solvent control group at the same time points. The expression of PARP-1 mRNA and protein in 20 mg/L nano-SiO_2 group was lower than that in the micro-SiO_2 control group at the same 12. 0 and 24. 0 hours time point( P < 0. 05). The above two indexes of cells were higher in curcumin group than that of 20 mg/L nano-SiO_2 group at the 12. 0 hours time point( P < 0. 05). CONCLUSION: Nano-SiO_2 stimulation can lead to decrease survival of 16 HBE cells in a dose-dependent manner and down-regulation of PARP-1 expression may be one of the mechanisms of proliferation and inhibition of 16 HBE cells induced by nano-SiO_2. Curcumin has certain protective effect on nano-SiO_2-induced 16 HBE cell injury.

Effect of curcumin on nano-silicon dioxide induced oxidative damage in A549 cells / 中国职业医学

OBJECTIVE: To study the effect of curcumin on the oxidative stress induced by nano-silicon dioxide( SiO_2) in A549 cells and to explore its potential mechanism. METHODS: A549 cells were randomly divided into 6 groups. Nano-SiO_2 group cells were stimulated with nano-SiO_2 solution with a final concentration of 20 mg/L; curcumin low-,medium-,and high-dose group cells were treated with curcumin at final concentrations of 5,10,and 20 μmol/L respectively and 20 mg/L nano-SiO_2 solution; the solvent control group was treated with dimethyl sulfoxide with a volume fraction of 0. 10%. The cells in the blank control group were not given any treatment. The cells in these 6 groups were incubated for 12 hours,and the level of malondialdehyde( MDA) and the activity of total superoxide dismutase( T-SOD) in the cells were measured by spectrophotometer. The relative expression of mRNA and protein of nuclear factor E2-associated factor 2( NRF2),thioredoxin-1( TRX1),and thioredoxin interaction protein( TXNIP) were analyzed by real-time fluorescent quantitative polymerase chain reaction and Western blot respectively. RESULTS: The MDA level in A549 cells of nano-SiO_2 group increased( P < 0. 05),the T-SOD activity decreased( P < 0. 05),and the mRNA and protein relative expression of NRF2 and TRX1 were up-regulated( P < 0. 05),TXNIP relative expression of mRNA and protein were down-regulated( P <0. 05),when compared with the blank control group and the solvent control group. After intervention with curcumin,with the increased of curcumin concentration,the MDA level in A549 cells decreased,the T-SOD activity increased,the relative expression of NRF2 mRNA and TRX1 mRNA and protein was up-regulated,the mRNA and protein relative expression of TXNIP was down-regulated,and showed a dose-dependent manner( P < 0. 01). CONCLUSION: Curcumin can protect nano-SiO_2-induced oxidative stress in A549 cells. It may activate TRX system by regulating NRF2/antioxidant response elements pathway,exerting an anti-oxidation effect and protecting cells from excessive oxidative damage.

A Highly Sensitive Electrochemical Biosensor for Detection of Adenosine Triphosphate Based on Space Block / 分析化学

In this work,a highly sensitive electrochemical biosensor for the detection of trace adenosine triphosphate (ATP) was proposed.The biosensor was based on porous anodic alumina (PAA) and SiO2 nanoparticles combining with several oligonucleotides to construct sandwich structure.It was characterized by scanning electron microscopy,fluorescence microscopy,differential pulse voltammetry and electrochemical impedance spectroscopy,which conformed to the reliability of the biosensor fabrication and the feasibility of the detection.In the presence of ATP,the sandwich structures could be destroyed.The variation of the current was directly corresponding to the amount of the ATP.The application of SiO2nanoparticles could effectively reduce the background and increase the sensitivity of the biosensor.The calibration curve of ATP was obtained in the range of 0.025-0.900 nmol/L with the detection limit of 13 pmol/L (S/N=3).Also,the biosensor exhibited a good specificity.Besides,the sensor was constructed easily and possessed excellent regeneration ability.The proposed biosensor was applied in detection of real sample such as mice blood.Therefore,the proposed ATP-sensing biosensor could be expected to be applied in clinical,pharmaceutical and environmental detection.

Mechanism of epithelial-mesenchymal transition induced by free silicon dioxide in type Ⅱ alveolar epithelial cells / 中国职业医学

OBJECTIVE: To investigate the epithelial-mesenchymal transition(EMT) induced by direct or indirect exposure to free silicon dioxide(SiO_2) and the expression of surface protein marker in rat typeⅡalveolar epithelial cell RLE-6TN.METHODS: i) The alveolar macrophages(AM) were isolated from specific pathogen-free SD rat by bronchoalveolar lavage.AM and RLE-6TN were treated with 0-140 mg/L(final concentration) of SiO_2 suspension and were cultured conventionally for 24,48 and 72 hours. The cell viability was detected by CCK-8 assay. The result of CCK-8 essay was used to choose the SiO_2 concentration for the following study. ii) To establish models of RLE-6TN co-cultured with AM that were seeded in Transwell. The cells were divided into 4 groups: the direct control group(RLE-6TN,no SiO_2 exposed),the direct exposure group(RLE-6TN,treated with 100 mg/L SiO_2),the indirect control group(RLE-6TN and AM were cocultured,no SiO_2 exposed) and the indirect exposure group(RLE-6TN and AM were co-cultured,AM was treated with 100 mg/L SiO_2 directly). Western blotting was used to detect the expression of E-cadherin(E-cad) and α-smooth muscle protein(α-SMA) after cells were cultured for 0,24,48 and 72 hours. RESULTS: i) According to the CCK-8 assay,the final concentration of 100 mg/L SiO_2 was chosen for the following study. ii) The difference of relative expression of E-cad andα-SMA in RLE-6TN was statistically significant in different treatment combination and time(P < 0. 01). The E-cad expression of RLE-6TN at 48 and 72 hours in the direct exposure group and the indirect exposure group was lower than that in direct control group at the same time point(P < 0. 05). The E-cad expression in RLE-6TN at 72 hours in the direct exposure group was lower than that in the 0 and 24 hours(P < 0. 05). The E-cad expression in RLE-6TN at 48 and 72 hours in the indirect exposure group was lower than that in the 0 hour(P < 0. 05). At 48 and 72 hours,the α-SMA expression in the indirect exposure group and the direct exposure group was higher than that in their control groups at the same time point(P < 0. 05). The expression of α-SMA in the indirect exposure group was higher than that in the direct exposure group(P < 0. 05). The expression of α-SMA in both exposure groups increased in a time-effect relationship(P <0. 05). CONCLUSION: Direct or indirect exposure to free SiO_2 can induce EMT in RLE-6TN,and decrease the expression of E-cad and increase the expression of α-SMA in a time-effect relationship. Indirect exposure group is more susceptible to EMT.