Based on the analysis of the problems of traditional medical literature retrieval teaching,taking North Sichuan Medical College as an example,the paper discusses the reform practice of medical literature retrieval course teaching from the aspects of enriching teaching contents,constructing literature retrieval excellent resource shared course,online practice and examination platform and controlling teaching quality strictly,etc.

Objective To determine the triterpenoid content in Loquat leaf by using HPLC method and to explore the feasibility of ursolic acid and oleanolic acid as the quantitative markers for determination of Loquat leaf and its preparations.Methods Two desugaring methods of Loquat leaf extracts were compared.The contents of ursolic acid and oleanolic acid in Loquat leaf as well as preparations were measured based on a system of HPLC,with a Dumas Diamonsil C18 column (250 mm×4.6 mm,5 μm) was used as analytical column.The mobile phase was consisted of acetonitrile-0.1% phosphoric acid (95∶5) with the flow rate of 0.5 mL·min-1.The column temperature was 30 ℃,the injection volume was 10 μL, the detective wavelength was 210 nm.Results Ursolic acid and oleanolic acid were measured in both Loquat leaf and its preparations,and their contents were fairy stable and comparable.Conclusion Ursolic acid and oleanolic acid can be served as quantitative markers for the determination of Loquat leaf and its preparations.

Postprandial hypotension is an abnormal regulation of blood pressure, which is common in the elderly. Due to insidious symptoms, postprandial hypotension is easily neglected by patients and medical staff in clinical practice, but it has a high degree of harm. There are many factors related to the occurrence of postprandial hypotension, including demographic factors, disease-related factors, lifestyle factors, postprandial postural factors and so on. Among demographic factors, age is positively associated with the occurrence of postprandial hypotension. Among disease-related factors, the existence of some basic diseases such as hypertension and diabetes, and the use of most kinds of anti-hypertensive drugs can increase the risk of postprandial hypotension. Among lifestyle factors, smoking is a risk factor for postprandial hypotension: while reducing the intake of staple foods, drinking large amounts of water or drinking green tea before meals may reduce the risk of postprandial hypotension. By taking different postures after meals, postural factors affect the rate of gastrointestinal emptying and then affect the occurrence of postprandial hypotension. Among the above factors, it is feasible to prevent postprandial hypotension by changing postprandial posture.

Objective: To show development status of postprandial hypotension studies comprehensively and intuitively in order to provide a reference for nursing research on postprandial hypotension. Methods: The data was from the literatures included in Web of Science database from 1986 to 2019 related to postprandial hypotension, and CiteSpace information visualization software was used to analyze the issuing country and institution, cited authors, Cited journals, keywords and cited references to postprandial hypotension. Results: A total of 1 140 literatures were obtained. 187 papers were finally included after screening. University of Adelaide in Australia has the most of published articles and the most of cited authors; The cited journals mainly include international high-impact journals such as Annals of Internal Medicine and Journal of the American Geriatrics Society. Through keywords clustering, a total of 5 research hotspots were obtained, including falls, insulin, autonomic nervous system, aged cared, gastrointestinal. Conclusions Postprandial hypotension is one of the convergence points of interdisciplinary fusion. At present, preliminary results have been obtained, but the research on its mechanism is still in the exploratory stage. Falls, insulin, autonomic nervous system, aged cared, gastrointestinal are currently the main focus of postprandial hypotension researches. The prevention of postprandial hypotension has made some achievements, but there are also some risks. It is necessary to conduct further studies on more convenient and safe measures to prevent postprandial hypotension.

Objective    To summarize the clinical experience in the treatment of high-risk patients with severe aortic valve disease by transcatheter aortic valve implantation (TAVI) via heart apex approach and to evaluate the early efficacy. Method    Five patients who underwent TAVI via heart apex approach from September 2017 to February 2019 in Henan Thoracic Hospital were retrospectively analyzed, including 3 males and 2 females, aged 65-84 (74.6±4.5) years. Result    All operations were performed through a small left incision into the thoracic cavity (3-5 cm), and then through the J-Valve transport system, the aortic valve was successfully released via heart apex after precise positioning under digital subtraction angiography. One patient developed ventricular fibrillation during the operation, and the operation was completed with the assistance of emergency femoral arteriovenous catheterization cardiopulmonary bypass; one patient underwent percutaneous coronary intervention first because of severe coronary stenosis; one patient had paroxysmal atrial fibrillation during the perioperative period, and had hepatorenal insufficiency and thrombocytopenia after the operation, and was improved after medical treatment; one patient had perivalvular leak during the operation, and was improved after re-implantation of the valve; one patient was in stable condition during operation and recovered smoothly after operation. Surgery was successful in all 5 patients. The follow-up time was 2-19 months, and the early clinical effect was good. Conclusion    The short-term clinical efficacy of TAVI via heart apex approach in the treatment of high-risk severe aortic valve disease is definite and safe, but the long-term and medium-term effects need to be further evaluated.