OBJECTIVE:To develop a rapid RP-HPLC quantitative determination of lamivudine(LAM) in mouse serum and tissue homogenates METHODS:0 1ml of serum of tissue homogenates and 0 5ml of methanol were vortexed in a plastic tube for 30s and the mixture was then centrifuged at 15 000r/min for 10min 20?l of the resulting supernatant was directly injected and LAM was chromatographed on a reversed-phase Kromasil C column(150mm?4 6mm,5?m) using a mixture of phosphate buffer(pH6 8)and methanol(91∶9,v/v)and monitored at 270nm RESULTS:The standard curves were linear over a range from 0 25?g/ml to 50?g/ml The minimal detectable drug concentration was 60ng/ml(S/N=3) The average extraction recovery of LAM was more than 88% The average methodological recoveries of LAM ranged from 97% to 100% The within-dayand between-day precisions were less than 10% CONCLUSION:The assay is economic,simple,rapid and specific

Objectives To explore the clinical diagnosis and treatment of Dieulafoy disease in children. Method The clinical features, endoscopic features and treatment of Dieulafoy disease in a child were reviewed. Results The 2-year-5-month old girl was admitted due to hematemesis for 7 hours. She was diagnosed of Dieulafoy disease by the typical endoscopic appearance. Gastroscopy showed that the lesion was located in gastric angle which was the predilection position of Dieulafoy disease. The small red blood vessels in the central part of the erosion area was exposed on the mucosal surface. The high frequency electrocoagulation under gastroscope was performed and effect was definite. Conclusion Dieulafoy disease is rare in children and lacks obvious clinical features. Endoscopic treatment has definite effect with little trauma and is the first choice of treatment.

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.

Objective To access the effects of 70 kV tube voltage combined with low dose and low concentration of contrast medium in coronary CT angiography (CCTA)by evaluating the image quality,radiation dose and contrast medium dosage.Methods Ninety patients suspected with coronary artery disease with body mass index(BMI)of less than 25 kg/m2and heart rate (HR)of less than 75 beats per minute were enrolled.The patients were randomly divided into three groups (n=30 for each group):Group A,100 kV of tube voltage with 370 mg I/mL iopromide,1 mL/kg;Group B,80 kV with 270 mg I/mL iodixanol,1 mL/kg;Group C,70 kV with 270 mg I/mL iodixanol,0.8 mL/kg.All the patients underwent CCTA with a 256 row wide-coverage volumetric CT.Automatic tube current modulation technique was applied.The images were reconstructed by adaptive statistical iterative reconstruction V (ASIR-V).The subjective image quality scores were compared with rank-sum test.The signal-to-noise ratio (SNR),contrast-to-noise ratio(CNR),effective dose(ED)and the total iodine intake were calculated and compared with one-way ANOVA.Results No statistically differences in age,gender,heart rate and BMI were observed among the three groups (P>0.05).Subjective image quality scores had no difference among the three groups (P>0.05).The CT values of group C were higher than those of group A(P<0.05).The image noise of group C was higher than that of group A and group B (P<0.05).No significant differences in SNR and CNR were noticed among the three groups (P>0.05).The ED of group B (0.39±0.08)mSv and group C (0.19±0.01)mSv were lower than that of group A (0.81±0.19)mSv (each P<0.05).Compared with group A,the decrease rates of ED of group B and C were 51.8% and 76.5% respectively.Compared with group A and group B,the total iodine intake of group C was decreased by 25% and 21.4% (P<0.05).Conclusion 70 kV of tube voltage combined with low dose and low concentration of contrast medium in CCTA can reduce the radiation dose and iodine intake without compromising image quality.