Study on the disinfection effect of chlorine dioxide disinfectant (ClO2) on dental unit waterlines and its in vitro safety evaluation.

BACKGROUND: Ensuring the safety of dental unit waterlines (DUWLs) has become a pivotal issue in dental care practices, focusing on the health implications for both patients and healthcare providers. The inherent structure and usage conditions of DUWLs contribute to the risk of biofilm formation and bacterial growth, highlighting the need for effective disinfection solutions.The quest for a disinfection method that is both safe for clinical use and effective against pathogens such as Staphylococcus aureus and Escherichia coli in DUWLs underscores the urgency of this research. MATERIALS: Chlorine dioxide disinfectants at concentrations of 5, 20, and 80 mg/L were used to treat biofilms of S. aureus and E. coli cultured in DUWLs. The disinfection effectiveness was assessed through bacterial counts and culturing. Simultaneously, human skin fibroblast cells were treated with the disinfectant to observe changes in cell morphology and cytotoxicity. Additionally, the study included corrosion tests on various metals (carbon steel, brass, stainless steel, aluminum, etc.). RESULTS: Experimental results showed that chlorine dioxide disinfectants at concentrations of 20 mg/L and 80 mg/L significantly reduced the bacterial count of S. aureus and E. coli, indicating effective disinfection. In terms of cytotoxicity, higher concentrations were more harmful to cellular safety, but even at 80 mg/L, the cytotoxicity of chlorine dioxide remained within controllable limits. Corrosion tests revealed that chlorine dioxide disinfectants had a certain corrosive effect on carbon steel and brass, and the degree of corrosion increased with the concentration of the disinfectant. CONCLUSION: After thorough research, we recommend using chlorine dioxide disinfectant at a concentration of 20 mg/L for significantly reducing bacterial biofilms in dental unit waterlines (DUWLs). This concentration also ensures satisfactory cell safety and metal corrosion resistance.

The association of Bcl-2 gene polymorphism with the esophageal cancer and gastric cardia adenocarcinoma in Hebei Province / 中华预防医学杂志

Objective@#To investigate the association between the promoter region-938 polymorphism of B-cell lymphoma/leukemia-2 (Bcl-2) gene and the esophageal cancer (EC) and gastric cardia adenocarcinoma (GCA) in Hebei Province. @*Methods@#From 2007 to 2010, 145 esophageal cancer patients and 169 cardiaccancer patientsfrom the outpatient department of the Fourth Hospital of Hebei Medical Universitywereselected in a case group, and 195 non-tumor patients were selected in a control group during the same period. A questionnaire survey was used to collect information of research subjects. Pathological tissues were collected to extract genomic DNA and detect the genotype of bcl-2 gene -938. A multivariate logistic regression model was used to analyze the association between the bcl-2 gene locus 938 CC genotype and the EC and GCA. The interaction between age, gender, smoking, drinking, upper gastrointestinal family history and the bcl-2 gene locus 938 CC genotype was analyzed by likelihood ratio test. @*Results@#The age of the esophageal and cardiac cancer groups was (56.3±8.3) and (57.1±8.4) years old, and that of the control group was (54.7±7.1) years old. The proportion of the bcl-2 gene locus 938 CC genotype in the esophageal group [48.3% (70/145)] and the cardiac cancer group [48.5% (82/169)] was higher than that in the control group [33.8% (66/195)] (both P values<0.05).Compared with the AA genotype, the risk of esophageal cancer and cardiac cancerin people with the CC genotype was 2.386 (1.20-4.76) and 2.564 (1.27-5.18) respectively. In the population with CC genotype, compared with the positive family history, drinking, and male, the negative family history, non-drinking, and female had a higher risk of esophageal cancer; compared with the non-smoking, negative family history, non-drinking and male, the smoking, positive family history, drinking, and female had a higher risk of cardiac cancer (all the P interaction values were <0.05). @*Conclusion@#People with bcl-2 gene locus 938 CC genotype in Hebei Provincewere more likely to suffer from the esophageal and gastric cardia adenocarcinoma.

Notch signaling pathway regulates epithelial-mesenchymal transition and affects the invasiveness and drug resistance of bladder cancer / 基础医学与临床

Objective To investigate the effect of notch signaling pathway on drug resistance and invasiveness of bladder cancer .Methods We observed the changes of growth and morphology of bladder cancer T 24 , 5637 and J82 cells which treated for 48 hours using γ-secretase inhibitor by inverted microscope .The mRNA and protein lev-els of the EMT molecular markers , including E-cadherin , N-cadherin , vimentin and Alpha-smooth muscle actin were examined by RT-PCR and Western blot in bladder cancer cells;Detected the changes of drug resistance and invasion respectively by MTT and Transwell in bladder cancer cells .Results After completely blocking the Notch signaling pathway , the inverted microscope showed that bladder cancer cells became smaller and more disperse ;RT-PCR and Western blot showed the mRNA and protein levels of E-cadherin were up-regulated ( P<0.05 ) , contrast , N-cadherin , vimentin and Alpha-smooth muscle actin were down-regulated ( P<0.05 ); The prolifera-tion of bladder cancer cells were significantly inhibited by MTT test;The number of through microporous membrane cells significantly decreased ( P<0.05 ) shown by Transwell test .Conclusions The Notch signaling pathway is completely blocked that nhibites proliferation and EMT of bladder cancer cells , reduces drug resistance and inva-sion in bladder cancer cells .It suggests that drug resistance and invasiveness of bladder cancer can be changed through EMT which is regulated through notch signaling pathway .