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ObjectivesPeriodontitis affects the progression of many diseases, while its detailed mechanism remains unclear. This study hopes to provide new ideas for exploring its mechanism by analyzing the gut microbiota and fecal metabolic characteristics of experimental periodontitis rats.MethodsA total of 10 rats were randomly divided into ligature-induced experimental periodontitis (EP) group and healthy control group. After 4 weeks of the experiment, the feces of all rats were collected for sequencing through 16S ribosomal DNA (rDNA) sequencing technology and liquid chromatography–mass spectrometry (LC–MS).Results16S rDNA sequencing results showed that the β-diversity of gut microbiota was significantly different between the EP and control group, and the levels of dominant genera were different. Compared with the control group, Ruminococcus, Escherichia, and Roseburia were significantly enriched in EP, and Coprococcus, Turicibacter, Lachnospira were significantly decreased. Correlation analysis showed that Roseburia exhibited the highest correlation within the genus. Of 3,488 qualitative metabolites, 164 metabolites were upregulated and 362 metabolites were downregulated in EP. Enrichment analysis showed that periodontitis significantly changed 45 positive/negative ion metabolic pathways. Five KEGG pathways, protein digestion and absorption, tyrosine metabolism, glycolysis/gluconeogenesis, niacin and nicotinamide metabolism, and oxidative phosphorylation, are enriched in both the microbiome and metabolome. Correlation analysis showed that the genera with significant differences in periodontitis were usually significantly correlated with more metabolites, such as Roseburia, Lachnospira, Escherichia, Turicibacter, and Ruminococcus. The genera with the same changing trend tended to have a similar correlation with some certain metabolites. In addition, vitamin D2 and protoporphyrin IX have the most significant correlations with microorganisms.ConclusionOur study reveals that periodontitis alters gut microbiota and fecal metabolites. The correlation analysis of microbiota and metabolome provides a deeper understanding of periodontitis, and also provides a direction for the study of periodontitis affecting other diseases.

ObjectiveThe quality and rationality of many recently registered clinical studies related to coronavirus disease 2019 (COVID-19) needs to be assessed. Hence, this study aims to evaluate the current status of COVID-19 related registered clinical trial.MethodsWe did an electronic search of COVID-19 related clinical studies registered between December 1, 2019 and February 21, 2020 (updated to May 28, 2020) from the ClinicalTrials.gov, and collected registration information, study details, recruitment status, characteristics of the subjects, and relevant information about the trial implementation process.ResultsA total of 1,706 studies were included 10.0% of which (n=171) were from France, 943 (55.3%) used an interventional design, and 600 (35.2%) used an observational design. Most of studies (73.6%) aimed to recruit fewer than 500 people. Interferon was the main prevention program, and antiviral drugs were the main treatment program. Hydroxychloroquine and chloroquine (230/943, 24.4%) were widely studied. Some registered clinical trials are incomplete in content, and 37.4% of the 1,706 studies may have had insufficient sample size.ConclusionThe quality of COVID-19 related studies needs to be improved by strengthening the registration process and improving the quality of clinical study protocols so that these clinical studies can provide high-quality clinical evidence related to COVID-19.

Recently WHO has characterized COVID-19 as a pandemic. Diagnosing the disease accurately and decreasing misdiagnoses and missed diagnoses is very important for management. Therefore, we have analyzed the seven versions of China's national guidelines to examine how the diagnostic criteria roadmap has developed and evolved, in order to share our experience worldwide. In this article, we present the developments from the first to seventh versions, involving changes of case classification, changes to “suspected case,” changes in “confirmed case,” changes in clinical classifications, changes in “severe case,” and unchanged criteria. We have also discussed the reasons and implications for these changes and are looking forward to providing suggestions for worldwide understanding and management of this pandemic. A nucleic acid test is currently accepted as the gold standard method to confirm diagnosis. In addition, imaging examination and epidemiological history should also be considered as auxiliary diagnosis methods.

ObjectiveTo systematically evaluate the quality of clinical practice guidelines (CPG) for medically treating benign prostatic hyperplasia (BPH), and to compare the context of recommendations in order to provide references for clinical application.MethodsWe searched databases of National Guideline Clearinghouse (NGC), Guidelines International Network (GIN), National Institute for Health and Clinical Excellence (NICE), Scottish Intercollegiate Guidelines Network (SIGN) and World Health Organization (WHO), PubMed, Embase, CNKI, VIP, WanFang Data, CBM, and Medlive from their establishment to October 13, 2019, to collect evidence-based guidelines and/or consensus on BPH. Method quality of included guidelines was assessed according to the Appraisal of Guidelines for Research and Evaluation II (AGREE II) instrument, and differences and similarities among recommendations were compared.ResultsA total of 22 guidelines were included, of which eight were updated versions. According to the AGREE II instrument, the median score of scope and purpose, stakeholder involvement, rigor of formulate, clarity of presentation, applicability, and editorial independence was 71.5%, 41%, 25%, 64%, 18%, and 28%, respectively. Based on recommendations for medical treatment, almost all guidelines recommended α1-blockers and 5α-reductase inhibitors, and most guidelines also recommended muscarinic receptor antagonists. In terms of drug combination therapy, most guidelines recommended “α1 blockers and 5α-reductase inhibitors”, and some guidelines also recommended “α1 blockers and muscarinic receptor antagonists”.ConclusionThe recommendations from different guidelines were basically similar, only showing conflicts in some areas. The quality of included guidelines remains to be unified, and their context can provide valuable implications for development or improvement.

Objective: The current study is aimed at exploring the relationship between chronic periodontitis and serotonin transporter (5-HTT) gene polymorphisms (rs6354 and rs12449783) in the Chinese Han population.Methods: This study included a total of 120 patients with chronic periodontitis and 125 healthy control subjects. The 5-HTT gene (rs6354 and rs12449783) was genotyped using oral mucosal tissue with a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Linkage disequilibrium was examined using Haploview. Genotype and allele frequencies were compared between the cases and controls using a χ2 test.Results: Genotype distribution of the 5-HTT gene polymorphisms rs6354 and rs12449783 in the control group conformed to Hardy–Weinberg equilibrium. The frequency of the AC genotype, the AC + CC genotype and C allele of the 5-HTT rs6354 polymorphism was higher in cases (P < 0.05) vs. the healthy control. The adjusted odds ratio (OR) was 1.910 (95%CI = 1.049–3.476) for the AC genotype, 2.026 (95%CI = 1.115–3.680) for the AC+CC genotype, and 1.875 for the C allele (95%CI = 1.089–3.228. Such an association was particularly strong in women for the AC genotype (OR = 2.167, 95%CI = 1.034–4.542). The genotype and allele frequencies of rs12449783 did not differ between the cases and controls. Haplotype C-C (rs6354-rs12449783) was also more frequent in the cases (OR = 2.372, 95%CI = 1.154–4.875, P = 0.016).Conclusion: Chronic periodontitis is associated with the 5-HTT gene rs6354 polymorphism, as well as rs6354/rs12449783 interaction.

Background: In recent decades, research on drug therapy for ventilator-associated pneumonia (VAP) remains one of the major hot-spots in the field of critical care medicine, but relevant data are not satisfactory. Our aim was to assess the status and trends of the most cited articles on drug therapy for VAP through bibliometric approaches.Methods: The Institute for Scientific Information (ISI) Web of Science core collection database was searched for the VAP-related articles. The time period for retrieval was from the beginning of the database to September 30, 2018. The top 100 most cited articles were selected to obtain their information on the authors, title, publication, number of citations, author’s affiliations, country, etc. These general information and bibliometric data were collected for analysis. VOSviewer software was used to generate a term co-occurrence graph that visualized a reference pattern for different terms in the 100 articles.Results: The number of citations for the 100 selected articles ranged from 142 to 3,218. These articles were published in 31 different journals. The top three journals in terms of the number of our selected articles they published were “Critical Care Medicine” (17 articles), “American Journal of Respiratory and Critical Care Medicine” (11 articles) and “Clinical Infectious Diseases” (10 articles). The most frequently nominated author was Marin H. Kollef from the University of Washington, and of the top 100 articles, 16 listed his name. These top 100 articles were published after the year of 2000. The most common type of article in the top 100 was an original article (53%). The United States and France were the countries that contributed the most articles to the top 100. Gram-negative bacilli, pseudomonas aeruginosa, antibiotics, risk factors and other terms appeared more frequently, suggesting that attentions on this issue currently focused on the rational application and management of antibiotics.Conclusion: This study analyzed the 100 most cited articles on drug-treated VAP, and provided insights into the historical developments and characteristics of the most cited articles in the field of VAP.