OBJECTIVE To investigate the use of a chlorine dioxide-based dental unit waterline(DUWL) treatment to reduce the colonization and growth of heterotrophic bacteria.METHODS Twenty-two dental units with self-contained water systems were randomly selected.Three of the units and tap water served as controls.Twenty-three water samples were taken at baseline and once a week for five weeks.They were serially diluted,spread-plated in duplicate onto R2A agar plates and incubated at 37 ℃ for 7 days.RESULTS At baseline,the 3 control DUWLs had a median count of 8440 colony-forming units/milliliter(CFU/ml) and the 19 treated DUWLs had a median count of 9160 CFU/ml.By week 1,18 of the 19 treated DUWLs had counts of less than 200 CFU/ml,and by week 4,the median count for all of the treated DUWLs was 0 CFU/ml.The measurement at week 5 showed that the reduction to below 200 CFU/ml had been maintained.Scanning electron examination revealed a similar results,with biofilm accumulation more evident in the untreated control specimens.CONCLUSIONS Using a chlorine dioxide-based disinfectant in DUWLs can achieve the American Dental Association(ADA) goal of less than 200 CFU/ml of heterotrophic bacteria per milliliter of unfiltered output water.

OBJECTIVE To observe the effect of flushing dental handpieces to prevent suction-induced contamination and to lower the bacterial level in dental unit waterlines,and then to analyze the time-effect relationship of flushing.METHODS Twelve BienAir handpieces(group A) and 12 W&H TA-96 handpieces(group B) were employed in this study.The water samples from each handpiece′s outlet were immediately taken once when operations of de-caries,cavity-preparing and dental-drilling had been completed,and then taken once per 0.5 min while the handpieces were being flushed by running without work for 4 min.The bacterial colony formation of these water samples was counted on R2A agar plates.Colony forming units vs flushing time were then compared.RESULTS Alike in groups A and B,water bacterial levels were lowered the most significantly while flushing the handpieces for 0.5 min.BienAir or W&H TA-96 handpieces still showed decreased levels of water bacteria when being flushed for 3 or 2.5 min respectively.Afterwards,the flushing effect reached to a platform,that was,more flushing time didn′t bring the bacterial level down further.CONCLUSIONS Flushing handpieces by running without work can significantly reduce the level of bacterial contamination in the waterlines.Different types of handpieces may have different flushing time at which the most effect is reached.

Objective: To investigate the roles of N-acetyl-L-cysteine (NAC) against binge drinking-induced fatty liver in mice. Methods: SPF male C57BL/6 mice were randomly divided into 3 groups, i.e. control group, model group, and NAC/ethanol group (n=10). Mice in model and NAC/ethanol groups were exposed to 3 doses of ethanol (6 g/kg bw) to induced fatty liver, while mice in control group received equal volume and equal energy of maltodextrin solution. NAC was administered to mice at 1 h before ethanol exposure (100 mg/kg bw, i.p.). The mice were sacrificed at 6 h after the last ethanol exposure. The liver and epididymal adipose tissues were collected. Histopathological examination and biochemical assay kit were used to evaluate the fat accumulation, while Western-blot was performed to detect the protein levels of some key factors involved in fat metabolism in liver and adipose tissues. Results: Compored with control group mice, the liver index and liver weight were significantly increased compared with model group, the liver index and TG level in NAC/ethanol group mice were all significantly decreased (P<0.05). Histological examination showed NAC effectively suppressed binge drinking-induced fat accumulation in mice liver. In addition, NAC had no significant effects on the protein levels of peroxisome proliferator-activated receptor-α (PPAR-α), Acy-CoA oxidase (ACOX), sterol regulatory element binding protein 1 c (SREBP-1c) and fatty acid synthase (FAS). Furthermore, the protein levels of hormone sensitive lipase (HSL) did not significantly differ among 3 groups, whereas NAC prevented binge drinking-induced increase of HSL phosphorylation at ser563 and ser660. Conclusion NAC could effectively attenuate binge drinking-induced fatty liver, which might be associated with the inhibition of lipid mobilization by suppressing the phosphorylation of HSL.

Objective: To investigate the antagonistic effect of diallyl sulfide (DAS) against peripheral nerve injury induced by n-hexane in rats. Methods: A total of 68 adult male Wistar rats were selected, among which 50 were randomly selected and divided into blank control group, DAS control group (100 mg/kg·bw) , n-hexane model group, low-dose DAS intervention group (50 mg/kg·bw) , and high-dose DAS intervention group (100 mg/kg·bw) . A rat model of peripheral nerve injury was established by n-hexane exposure, and the rats were treated with DAS at different doses. The changes in pyrrole adducts and behavior were observed, a metabolic analysis was performed for serum pyrrole adducts, and the intervention effect was evaluated. The remaining 18 rats were randomly assigned to the n-hexane model group, the low-dose DAS intervention group, and the high-dose DAS intervention group, with 6 rats in each group, as satellite groups used for the toxicokinetic analysis of serum pyrrole adducts. Results: Compared with the blank control group, the n-hexane model group and low-and high-dose DAS intervention groups had a significant reduction in body weight since week 2 (P<0.01) . Compared with the n-hexane model group at the end of the experiment at week 7, the high-dose DAS intervention group had a significantly higher body weight (P<0.05) , while there was no significant difference in body weight between the n-hexane model group and the low-dose DAS intervention group (P>0.05) . The n-hexane model group developed gait abnormality at week 2 of poisoning, while the low-and high-dose DAS intervention groups developed gait abnormality at weeks 3 and 5 of poisoning, respectively. At the end of the experiment, the n-hexane model group and the low-and high-dose DAS intervention groups had a significantly higher gait score than the blank control group (P<0.01) . At the end of the experiment, the n-hexane model group and the low-dose DAS intervention group had significantly shorter latency in rotarod test than the blank control group (P<0.01) , while there was no significant difference in latency between the DAS control group and the high-dose DAS intervention group (P>0.05) . Compared with the n-hexane model group, the low-and high-dose DAS intervention groups had a significant increase in latency in rotarod test (P<0.01) . Compared with blank control group, the n-hexane model group and the low-dose DAS intervention group had a significant increase in mean nerve conduction velocity (P<0.01) , while there was no significant difference between the blank control group and the DAS control group or high-dose DAS intervention group (P>0.05) , and compared with the n-hexane model group, the low-and high-dose DAS intervention groups had a significant increase in nerve conduction velocity (P<0.01) . Compared with the blank control group at the end of the experiment at week 7, the n-hexane model group and the low-and high-dose DAS intervention groups had significant increases in the concentration of pyrrole adducts in serum, urine, and hair (P<0.01) , while there was no significant difference between the blank control group and the DAS control group (P>0.05) , and the high-dose DAS intervention group had a significantly lower concentration of pyrrole adducts in serum, urine, and hair than the low-dose DAS intervention group (P<0.05) . Serum pyrrole adducts reached the peak level at 9-12 hours and then started to decrease. Compared with the n-hexane model group, the high-and low-dose DAS intervention groups had a significantly shorter half-life period of serum pyrrole adducts (P<0.01) . Compared with the n-hexane model group, the high-and low-dose DAS intervention groups had a significant reduction in the area under the curve of serum pyrrole adducts (P<0.05) . Conclusion DAS can antagonize peripheral nerve injury induced by n-hexane.

Objective: To report an investigation of a family cluster of coronavirus disease 2019 ( COVID-19 ) in Ningbo, so as to provide reference for the prevention and control measures. Methods: According to the COVID-19 Prevention and Control Program ( fourth version ) , an epidemiological investigation was conducted to collect the demographic information, clinical features and exposure history, to find the close contacts, and to figure out the source and route of infection. Results: Twelve confirmed cases and one asymptomatic case were reported. The attack rate was 16.05%. Among them, five were males and eight were females; the age ranged from 11 to 85 years old, with a median of 39 years old; most had mild symptoms. The incubation period was 2-13 days, with a median of 6.5 days. The first case ( Case 1 ) developed the symptoms on January 22, and had close contact with Zhang, an asymptomatic case, on January 20. Zhang was related to a cluster in the Buddhist assembly on January 19. Case 1, who caused the spread of the epidemic among family members, participated in several family visits and dinners from January 22 to 27 with other 24 families, resulting in six secondary cases and six third-generation cases. There were 54 close contacts except the family members, no infection was found. Conclusion This family cluster may result from the close contact with an asymptomatic case, and then spread within families through having dinners and living together.

Objective To determine the effect of crocin regulating miR-139-5p/ATF4 axis on myo-cardial injury and energy metabolism in rats with CHF.Methods A total of 84 male SPF SD rats were randomly divided into sham operation group,model group,crocin low-,medium-and high-dose groups,captopril group and crocin+miR-139-5p inhibitor group,with 12 in each group.Car-diac function indexes,myocardial histomathological morphology,apoptotic rate,myocardial injury indexes,heart failure indexes,inflammatory indexes,oxidative stress indexes,myocardial ATP content,SDH activity,and miR-139-5p and ATF4 mRNA expression levels were detected in rats.The targeting relationship between miR-139-5p and ATF4 was verified.Results Compared with the conditions in the model group,crocin treatment at different doses reduced apoptotic rate of cardiomyocytes,decreased MDA content,LVEDD and LVESD values and cTnI,cTnT,CK-MB,NT-proBNP,TNF-α and IL-1β levels,and declined ATF4 mRNA level,and increased LVEF and LVFS values,SOD activity,ATP content,SDH activity and miR-139-5p level(P＜0.05).Com-pared with the crocin high-dose group,the crocin+miR-139-5p inhibitor group had higher apop-totic rate of cardiomyocytes[(22.68±3.25)％vs(11.94±1.38)％,P＜0.05],increased LVEDD and LVESD value,raised MAD content and cTnI,cTnT,CK-MB,NT-proBNP,TNF-α and IL-1βlevel,and elecated ATF4 mRNA level,and decreased LVEF and LVFS value,SOD activity,ATP content,SDH activity and miR-139-5p level(P＜0.05).There was a targeting relationship be-tween miR-139-5p and ATF4.Conclusion Crocin can improve myocardial injury and energy me-tabolism in CHF rats,which may be related to its regulation of miR-139-5p/ATF4 axis.

Objective To investigate the molecular mechanism of endothelial-mesenchymal transition (EndMT) induced by uremic toxin,parathyroid hormone (PTH),in vascular endothelial cells.Methods PTH (1 × 10-8 mol/L) was used to induce EndMT in human aortic endothelial cells (HAECs).TGF-β signaling inhibitor,including SB431542 and pirfenidone (PFD),and integrin-linked kinase (ILK) inhibitor Cpd22 were used to investigate the potential mechanism of EndMT induced by PTH in HAECs.Then the vascular endothelial cell markers VE-cadherin and CD31,and the mesenchymal marker α-SMA were detected by western blot.Results PTH reduced the expression levels of vascular endothelial cell marker CD31 and VE-cadherin (P＜0.05),while significantly increased the expression level of fiber cell marker α-SMA(P＜0.05).Furthermore,the TGF-βsignaling inhibitors (SB431542 and PFD) and ILK inhibitor (Cpd22) were able to partially reverse the EndMT induced by PTH in HAECs,which reversed the effect of PTH on reducing vascular endothelial cell marker expression and increasing fiber cell marker expression.Conclusion PTH could induce EndMT in HAECs via TGF-β/ILK pathway.