To date,the clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 system has been widely used to edit the genome in many species and cells.The system is the third generation of artificial endonuclease,which can edit DNA by recognizing short DNA sequences.This paper reviews the structural features of the system and its application in virus research,such as the functional studies of virus-related genes and the exploration of antiviral therapies (including HIV,HBV,and EB virus),looking forward to the future direc-tion of virus research.

OBJECTIVE:To validate the determination method of the content of Morphine in Compound Glycyrrhiza oral solution. METHODS: Samples were detected by solid phase extraction-HPLC on Kromasil C8 column (250 mm?4.6 mm,5 ?m) with mobile phase consisted of 0.05 mol?L-1 KH2PO4-0.0 025 mol?L-1 C14H15NaO3S?2H2O-acetonitrile using gradient elution.The detection wavelength was 220 nm and the flow rate was 1.0ml.min-1.RESULTS:The linear range of morphine was 2.02～20.2 ?g?mL-1(r=0.999 7),and the average recovery was 99.0%(RSD=0.40%,n=9).CONCLUSION: The method is accurate,sensitive and stable,and accurate and reliable in determination results.

Objective:To establish the bacterial endotoxin test method and the abnormal toxicity test method for reduced glutathi -one for injection.Methods:According to the requirements and methods in Chinese Pharmacopoeia (2015 edition, part IV), the bacte-rial endotoxin test and the abnormal toxicity test for reduced glutathione were studied .Results:The limit of bacterial endotoxin for re-duced glutathione was 0.125 EU· mg-1 , and the limit of abnormal toxicity was 1.0 g· kg-1 .Conclusion: The bacterial endotoxin test method and the abnormal toxicity test method are feasible .The abnormal toxicity should be supplemented in the quality standard for reduced glutathione , and the bacterial endotoxin test can replace the pyrogen test .

Objective To study the expression of p27kip1 and Ki67 proteins in various types of gastric polyp and the relationship be-tween gastric polyp and gastric carcinoma (CA:). Methods The expression of p27kip1 and Ki67 proteins were detected in normal gastric mu-cosa, hyperplasie polyp, adenomatons polyp, and carcinoma by S-P immunohistochemical staining. Results In the normal gastric mucosa,hyperplasie polyp, adenomatous polyp and gastric carcinoma, the expression rate of the p27kip1 protein was 90. 00% ,70. 00% ,65.00% and 30. 43%, respectively. The positive rate of p27kip1 protein in gastric cancer was significantly lower than that in other tissues. The rate of Ki67 protein expression in those tissues was 10. 00%, 15.00%, 45.00%, and 73.33%, respectively. The positive rate of Ki67 protein in gastric cancer was significantly higher than that in other tissues. And the positive rate of Ki67 in adenomatous polyp was significantly higher than that in the normal gnstric mucosa and hyperplasic polyp. There were significant differences among them(P <0.05). There was no correlation between the expression of p27kip1 and Ki67 proteins in gastric polyp(rs=-0. 093, P >0. 05). Conclusion Detection of p27kip1 and Ki67 proteins in gastric polyp was very helpful in early diagnosis and prognosis of GC.

Objective To test nursing assessment ability of new nurses,evaluate the training effects and find defects in the training of new nurses through nursing assessment using objective structured clinical examination,so as to guide the implementation of standardized training and explore new method that is suitable for the evaluation of effects of standardized training.Methods New nurses recruited in January 2015 in Baoding No.1 Hospital were selected as the research object. Standardized training manual was established and appraisal framework of objective structured clinical examination was designed. Objective structured clinical examination was carried out every two months during one year's standardized training. Standard cases and evaluation criteria were authorized. New nurses were evaluated according to the standard after test. The main problems exposed in examination and appraisal were used as the observational indexes. Scores up to 60 were set as fail and scores above 80 were defined as excellent nurses.Results A total of 41 new nurses took part in the assessment. The scores distributed in four ranges:above 80 (2 nurses),between 70 and 80 (12 nurses),between 60 and 70 (9 nurses) and below 60 (18 nurses). Problems during the nursing assessment contained inadequate understanding of content inquisition interview,ignoring assessment of patients' main symptoms and unreasonable evaluation score caused by incomprehensive assessing content,even though they had the awareness of risk assessment.Conclusions Through the objective structured clinical examination,we found that new nurses' ability of nursing assessment is low. The assessment reflects the main problems during standardized training and guides the improvement of clinical teaching and nursing. The appraisal procedure could be used as a new assessment method of new nurses' standardized training in hospital.

Clinical data of 62 patients with gastrointestinal submucosal tumors (diameter ≥1 cm) who were treated with kissing suture by single-channel endoscope after endoscopic full-thickness resection (EFR) in the First Affiliated Hospital of Zhengzhou University from February 2017 to May 2019 were analyzed retrospectively to evaluate the clinical value of kissing suture technique by single-channel endoscope in defect closure after EFR. All the post-EFR defects were successfully closed (100%). No postoperative anastomotic leakage or other serious complications occurred. The mean maximum diameter of lesions was 3 cm (ranged 1-7 cm), and 13 (21%) of them were greater than or equal to 5 cm.The mean number of clips used was 25.7 (ranged 7-78). The mean procedure time was 168 min (ranged 44-300 min), and the mean suture time was 63 min (ranged 13-211 min). The mean postoperative hospital stay was 7 days (ranged 4-12 days). Endoscopic reexamination 3-6 months after operation showed that all wounds healed well. Kissing suture method by single-channel endoscope is a safe, effective, easy and feasible for closing gastrointestinal defect after EFR.

From June 2017 to September 2019, 5 patients who were diagnosed as having benign severe pyloric stenosis underwent fully covered stent placement using a new stenting method at the First Affiliated Hospital of Zhengzhou University. Five patients were performed successfully without serious complications. Postoperative barium meal radiograph revealed that the stents were in good location and the acontrast agent passed smoothly. The liquid diet was commenced 1-3 days after surgery. No vomiting, abdominal pain and diarrhea occurred. During the follow-up, all the patients had improved weight and nutritional status. Four patients underwent stent removal 3-4 months postoperatively. One patient was found that the stent had migrated to stomach 3 months after discharge. After removing the stent, balloon dilation and mucosal resection was performed for the mild pyloric stenosis. All 5 patients had an additional follow-up of 3 months, and no symptoms and restenosis occured. These preliminary results showed that the new stenting method of fully covered stent placement is feasible, safe and effective in the treatment of benign pyloric stenosis.

Objective:To study the safety and effectiveness of endoscopic full-thickness resection(EFR) in the treatment of large gastric stromal tumors with diameter of 5-7 cm.Methods:Data of 36 patients with large gastric stromal tumors (5-7 cm) who received EFR or surgery (including laparoscopic and open surgery) in the First Affiliated Hospital of Zhengzhou University and confirmed by postoperative histopathology from January 2017 to October 2018 were retrospectively analyzed. Patients were divided into endoscopic group (9 cases) and surgical group (27 cases) according to different resection methods. The perioperative indicators and the total incidence of complications in the two groups were compared.Results:In terms of perioperative indicators, the median operation time of the endoscopic group was significantly longer than that of the surgical group (4.0 hours VS 2.0 hours, P<0.01), and the postoperative fasting time (4.55±0.88 days VS 6.22±2.24 days, t=-2.15, P=0.03) and hospital stay (6.88±1.26 days VS 10.03±2.90 days, t=-3.13, P<0.01) were significantly shorter than those of the surgical group. The median visual analogue scores (VAS) of abdominal pain of the endoscopic group on the first postoperative day (3 VS 6, P<0.01)and the third postoperative day (1 VS 3, P<0.01) were significantly lower than those of the surgical group. The hospitalization cost was significantly less than that of the surgical group (55±14.7 thousand yuan VS 73±24.3 thousand yuan, t=-2.11, P=0.04). In term of the total incidence of complications, the endoscopic group was 11.1% (1/9), which was higher than that of the surgical group [7.4% (2/27)], but there was no statistically significant difference( P=1.00). Conclusion:EFR is safe and effective in the treatment of large gastric stromal tumors (5-7 cm), and has the advantages of less invasiveness, rapid postoperative recovery, and lower hospitalization cost. But how to shorten the operation time is an urgent problem to be solved.

Objective To establish a method for content determination of total flavones and polysaccharides in Fangshu Qingre mixture by UV-Vis Spectrophotometry. Methods The contents of total flavones and polysaccharides in Fangshu Qingre mixture were determined by UV-Vis spectroscopy with rutin and anhydrous glucose as reference substance, and the wavelength was set at 508 nm and 487 nm. Results The contents were from 0.00 to 59.20 μg/ml for total flavones and from 10.92 to 109.20 μg/ml for total polysaccharides in Fangshu Qingre mixture. The recoveries of total flavones and total polysaccharides were 104.4% and 104.8% respectively. Conclusion The method of using ultraviolet spectroscopy was simple, reproducible, accurate and reliable, which could be preferably used as the method for content determination of total flavones and polysaccharides in Fangshu Qingre mixture.