There is a variety of gut microbiota in human body, which is closely associated with the health and disease. Normal gut microbiota can produce colonization resistance to pathogens. Antibiotics can affect the composition of gut microbiota and change the intestinal microenvironment, resulting in intestinal microecological disorders, which in turn cause intestinal pathogenic infections and other diseases. In this paper, the concept of intestinal microecology, the mechanism of intestinal colonization resistance, the effect of antibiotics on intestinal microecology, and the treatment methods were reviewed, aiming to provide the information for the rational use of antibiotics and the development of more effective treatment methods to maintain the stability of intestinal microecology.

Objective:To understand and compare the online learning effect of students majoring in stomatology and dental technology under the background of COVID-19 epidemic prevention and control, and to analyze the advantages and challenges of online teaching, so as to provide reference for the reform of teaching mode of stomatology education.Methods:A questionnaire survey on online learning was carried out among 267 students majoring in stomatology and 92 students majoring in dental technology in Chongqing Medical University. The results were statistically analyzed by SPSS 21.0, and chi-square test or rank sum test was used to count the data.Results:Computers and mobile phones are the main tools for students to study online. 52.92% of students used computers and 38.72% used smart phones. About 80% of the students said that they could adapt to online learning, and there was no statistical difference between the students of two majors. The online learning time of students majoring in stomatology was mainly 4-6 hours, while that of students majoring in dental technology was 2-4 hours, with statistical significance. However, the latter were more likely to ask questions to teachers than the former, and the proportion of students who often asked questions to teachers was 29.35% and 20.60%, respectively, with statistical significance. A small number of students of both majors failed log on the platform to learn and complete all the teaching materials on time. More than 50% of the students thought that online teaching was not as effective as offline teaching, and offline teaching was more conducive to mastering curriculum knowledge, without statistical differences between the students of two majors. They thought that the unsmooth learning platform, poor network conditions at home, and insufficient teaching materials prepared by teachers were the main reasons that affected the online learning effect.Conclusion:The online teaching is an important and also an advisable way to maintain teaching activities during the epidemic prevention and control of COVID-19. It will be the direction of further research on the education and teaching reform to make full use of information technology, combine the advantages of online teaching and traditional classroom teaching, and actively explore the blended teaching mode from the perspective of specialty and course characteristics.

Objective To investigate the morphologic features of Bachmann bundle (BB) and its vascular supply on dual-source CT coronary angiography(DSCTCA) in healthy volunteers and patients with coronary artery lesion (CAL). Methods Clinical histories, electrocardiograms (ECGs), and images of DSCTCA of 106 patients ( CAL group) and 100 healthy volunteers ( Control group) were reviewed. All 106 patients underwent conventional coronary angiography ( CCA ). The Gensini scoring system was used to assess the results of CCA. The patients were divided into three groups according to their Gensini scores. The length, width and superoinferior diameter, CT value, and vascular supply of BB were studied. Rank sum test for continuous variables and Chi-square test for categorical variables were used in statistical analysis.Results ( 1 ) BB visualization rate of control group was higher than CAL group [86.0% (86/100) vs 51.9%(55/106), x2 = 27.726, P ＜ 0.01]. The higher the Gensini score of CAL subgroup, the lower the visualization rate of its BB [80.0% ( 28/35 ), 55.6% ( 20/36 ), 20.0% ( 7/35 ), x2 = 25.530, P ＜ 0.01].(2)The median of measurements of length,width and superoinferior diameter of control and CAL group were 13.0 vs 13.8,5.0 vs 5.2 and 5.9 vs 6.2 mm, respectively ( P ＞ 0.05 ). (3) The CT value of the BB region in control group( median :42.6 HU ) was higher than that of CAL group( median: 13.0 HU) ( Z = - 7.061, P ＜0.01). The CT values of BB regions in patients with nonvisualized BB (median: -16.0 HU) were lower. The CT values of the BB regions in CAL group were negatively-correlated with Gensini scores( median:19.0) (r = -0.553, P ＜0.01 ). (4)The blood supply of BB and BB region was provided by right sinuatrial node artery ( SNA, 58.7%, 121/206 ), left SNA ( 35.9%, 74/206 ) or both SNAs ( 5.3%, 11/206 ).Conclusions DSCTCA could can show the anatomical characteristics of BB and its arterial supply. The serious the degree of CAL , the lower the BB display rate, and the higher the abnormal ECG incidence,which indicate that the occurrence of BB lesions is probably related to ischemia.

Objective To investigate the blood pressure control effect of captopril sustained-releasetablets based combination, antihypertensive therapy on hospitalized high-risk patients with hypertension in high altitude region. Methods According to the blood pressure,risk factors and combined target organ damage,331 hospitalized patients with essential hypertension were divided into 2 groups and accepted different treatment:low-risk group had monotherapy (n=102) , and night-risk group had captopril sustained-release-tablets based combination antihypertensive therapy (n =229). The discharge blood pressure,extent of SBP/DBP decrease and the compliance rate of discharge blood pressure of two groups were compared. Results The extent of SBP/DBP decrease in hight-risk group was significantly greater than low-risk group (SBP [36. 83 ± 22. 23] mm Hg vs.[28. 74 ±18.71] mm Hg,t=-3. 207,P <0. 05;DBP[22. 04±13. 57]mm Hg vs. [17. 98 ± 13.63] mm Hg,t =-2. 509, P < 0.05). The average discharge blood pressure in both groups reach the standard criterion, but no significant difference was observed between the two groups (SBP [125. 62 ± 14. 74] mm Hg vs. [122. 28 ±13.13]mmHg,t=-1. 962,P>0. 05;DBP[80. 67 ±9. 82]mm Hg vs. [78. 40 ±9. 97]mm Hg,t =-1.910,P > 0. 05). Furthermore we found no significant difference in the control rate of blood pressure between high-risk and low-risk group (72. 06% vs. 71. 57% , x2 = 0.928, P > 0. 05). Conclusion The captopril sustainedrelease-tablets based combination antihypertensive therapy is a reliable treatment in high-risk patients with hypertension from high altitude region,which shows satisfying blood pressure control rate.

Objective To investigate the protective effects of simvastatin on cobalt choride ( CoCl2 ) -induced hypoxia and reoxygenation injury on alveolar type Ⅱ cells and the underlying mechanisms.Methods CoCl2 was used to establish the hypoxia and reoxygenation injury model on AT Ⅱ cells.Blank,control and variant doses simvastatin-treated groups ( 5,10,20,30,50,100 μ mol/L) were designed in the present study.The proliferation of AT Ⅱ cells was evaluated by Cell Counting Kit-8 ( CCK-8 ) assay.The percentage of apoptotic cells was assessed by flow cytometry AV/PI double-staining.The protein levels of surfactant protein-C (SP-C) and proliferating cell nuclear antigen (PCNA) in AT Ⅱ cells was determined by Western blot.Results As compared with the control group,pretreatment with low dose (5 - 20 μmol/L),but not high dose simvastatin (50 - 100 μmol/L) markedly reduced A549 cells apoptosis,and increased their proliferation and the protein levels of SPC and PCNAin vitro.The protective effect could be reversed in vitro by L-mevalonate,a simvastatin competitive inhibitor,which indicated that the inhibition of mevalorate pathway was involved in the simvastatin induced AT Ⅱ cells function restoration.Condusion Low doses simvastatin reversed CoCl2-induced hypoxia and reoxygenation injury of AT Ⅱ cells.The inhibition of mevalonate pathway contributed to simvastatin induced AT Ⅱ cells function restoration.

Objective To investigate the clinical characteristics, operation time and methods for patients with central brain herniation caused by bifrontal contusions. Methods A retrospective study was performed on the medical records of patients with central brain herniation caused by bifrontal contusions admitted from January 2000 to December 2006. There were 45 males and 18 females, at age range of 20-72 years (average 43 years). The majority of the patients were victims of falls and traffic accidents. There were 29 patients treated with immediate operation and 34 with emergency operation. All the operations involved simultaneous bilateral craniectomy for decompression, including 17 patients treated with bilateral decompressive craniectomy and 46 with unilateral decompressive craniectomy. Results The prognosis was favorable in 19 patients with GOS score of 5 or 4 points, severely disabled in seven with GOS score of 3 points, vegetative in four with GOS score of 4 points and the worst in seven with GOS score of 1 point. Of all, 19 patients suffered severe mental disorders especially personality change and disturbance of intelligence. Seven patients were complicated by epilepsy and three by hydrocephalus. Conclusions Based on early clinical manifestations of central brain herniation combined with imaging manifestations, bilateral balance decompression craniectomy can reduce the mortality and morbidity and improve the cure rate of patients with central herniation caused by bifrontal brain contusions.

AIM: To identify the non-steroid transcription factors upregulating the expression of L-plastin in hormone-independent prostate cancer, and partly elucidate the mechanism of hormone-refractory prostate cancer. METHODS: TF SEARCH software was used to analysis the possible binding sites of transcription factors in the 3’ end of L-plastin promoter that had been identified as important part of regulation response elements. Gel shift assay and supershift assay were used to confirm the transcription factors binding the speculated response elements. PCR site-mutagenesis technique was performed to delete the binding site of transcription factor and luciferase activity assay was carried out after deletion of the binding site. RESULTS: SP-1 respond element GGTGGGGCGGGGA located at -54- -41 of L-plastin promoter was identified with the TF SEARCH software. Gel shift assay and supershift assay confirmed that SP-1 was the transcription factor binding to GGTGGGGCGGGGA. Mutant deleted the SP-1 binding-site had low-luciferase activity than that of the naive. CONCLUSION: SP-1 plays an important role in the up-regulation of L-plastin expression in hormone-independent prostate cancer.

Microbial lipases are important industrial biocatalysts with the character of stereoselectivity,site selectivity and high catalytic activity with few side effects.They have been used widely in many industrial and agricultural fields.The technology of protein engineering has been successfully applied to improve the activity and stability of microbial lipases,which will raise the competitive capacity of microbial lipase preparations and enlarge theirs application fields.The strategies,the problems and the prospects of protein engineering technology which have been applied to modify the microbial lipases was surveied.

Objective To evaluate the clinical effect of recombinant human epidermal growth factor (rhEGF) on the treatment of chronic tympanic membrane perforation and the function of inner ear. Methods From 2005 to 2008, the outpatients were randomly divided into three groups (A:control group, B:kangfuxin group, C:rhEGF group) . The patients were also divided into three groups (small, medium and large) . The hearing level and the function of inner ear in three groups were compared. Results The hearing level of rhEGF group was 4.5, which was significantly than that of other groups (7.3 and 9.4 respectively, <0.05) . There was no significant difference in the function of inner ear among the three groups ( >0.05) . Conclusion rhEGF can decrease the healing time significantly and increase the healing rates in the treatment of chronic tympanic membrane perforation, and it has no obvious adverse effects on the inner ear.

Objective To evaluate abdominal CT scan in predicting complications and mortality of acute pancreatitis patients. Methods CT imaging data of 606 AP patients from June 2010 to October 2011 were analyzed retrospectively. Fatty liver, pleural effusion, suprahepatic space effusion, biliary tract disease,gastric bare area involvement (GBAI),adrenal gland involvement (AGI) and perirenal space involvement (PSI) were evaluated,and the relationship between CT findings and complications and mortality was analyzed. Results (1) The Logistic regression analysis showed six risk factors for complications of AP,including obesity,fatty liver,PSI,AGI,GBAI and suprahepatic space effusion.The sensitivity,specificity and accuracy of Logistic regression model for predicting complications were 81.3％,89.1％ and 85.3 ％,respectively. (2) The Logistic regression analysis showed four risk factors for mortality of AP,including obesity,AGI,GBA and suprahepatic space effusion.The sensitivity,specificity and accuracy of Logistic regression model for predicting mortality were 33.3％, 98.6％, 96.0％, respectively.Conclusions Abdominal CT scan effectively indicates the signs of tissue and organ involvement in AP.These CT findings relate with the prognosis of AP.