Digestive Manifestations and Pathogenesis in Patients With COVID-19 / 胃肠病学

COVID-19 currently is a major pandemic disease in the world. It is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a member of the β-coronavirus genus that has 79% homology with severe acute respiratory syndrome (SARS) virus and can lead to acute respiratory infection. While COVID-19 patients typically present with respiratory symptoms such as fever, cough, some patients also report symptoms of digestive system. Studies have identified the SARS-CoV-2 RNA in stool specimens of infected patients, and the viral receptor angiotensin converting enzyme 2 (ACE2) is found to be expressed in gastrointestinal epithelial cells, hepatic cells and pancreatic cells, suggesting that fecal-mouth route is a potential route for transmission of SARS-CoV-2. This article reviewed the digestive manifestations and pathogenesis of patients with COVID-19.

Comparison of three different methods for isolating RNA from Oncomela-nia hupensis / 中国血吸虫病防治杂志

Objective To compare the effects of three kinds of Oncomelania hupensis RNA extraction methods,namely a modified SDS method,TRIzol reagent method,and CTAB method,so as to obtain an economical and efficient method for RNA extraction from O. hupensis. Methods The modified SDS method,TRIzol reagent method and CTAB method were applied to ex-tract the RNA from O. hupensis. A nucleic acid protein analyzer was used to measure the concentration and purity of RNA. The yields were calculated by the concentration of the products. The purity was indicated by A260/A280 and A260/A230. The quality of RNA was inspected by 1% agarose gel electrophoresis. The β-acting gene was selected as the target gene for RT-PCR analysis. Re-sults The RNA yields obtained by using the three kinds of extraction methods were significantly different(F = 16895.85,P <0.01)according to the analysis of variance. The LSD test showed that the yields obtained by using the modified SDS method were the highest,and those obtained by the CTAB method were the lowest. The purity of RNA extracted by the CTAB method was su-perior to that by the other two methods,and the A260/A280 and A260/A230 ratios of the CTAB method were in the range from 1.8-2.0 and 2.0-2.2. The A260/A230 ratios of the other two methods were both lower than 2.0. The RNA extracted by the modified SDS meth-od had the better integrity. The electrophoresis results showed that the 28S rRNA band,18S rRNA band and 5S rRNA band were clear,and there was no obvious smear between each band. The RNA obtained by the TRIzol reagent method had no 28S rRNA band,and that obtained by the CTAB method had no 28S rRNA and 5S rRNA bands. The β-acting gene of the RNA ex-tracted by all the three methods could be amplified by RT-PCR. The costs and time-consuming of the modified SDS method were less than those of the other two methods. Conclusion The modified SDS method is an economic and efficient method,and it is suitable for extracting the RNA of O. hupensis,especially for large sample preparation.