Objective To explore the traits of improved polyacrylamide gel electrophoresis (PAGE)-ethidium bromide(EB) staining in the detection of genotype polymorphisms.Methods The methods of PAGE-silver staining,agarose gel electrophoresis (AGE)-EB staining and improved PAGE-EB staining in polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) were used to detect the μ-opioid receptor (OPRM1) A118G genotypes in case group (n =167) infants with intracranial hemorrhage (ICH),and control group(n =163) infants without ICH,to conduct a case study analysis.And the application traits of three methods were compared.Results Genotypes of OPRM1 A118G were GG (169 bp),AG (193 bp,169 bp),AA (193 bp).Both the electrophoresis methods of PAGE-silver staining and PAGE-EB could be used to detect the genotypes of OPRM1 A118G clearly in this study.There was no statistically significant difference between the resolutions of DNA fragments (P =0.884).The first method,which had 13 experiment steps,consuming 4-5 hours,involving 12 kinds of chemical reagents,and the pictures were taken with the camera,was complex,with difficult operation,more time consuming; Compared with the first method,the secondmethod was simple,which had 6 test procedures,consuming 2 hours with 8 reagents,and the pictures were taken by using an automatic gel imager.AGE-EB could not be used to detect genotypes of OPRM1 A118G.Conclusions The method of improved PAGE-EB has the advantages of fast,easy operation,and high resolution,which is worthy of wider application.

Objective:To explore the correlation between the index of hemodynamics in perinatal period and retinopathy of prematurity(ROP), so as to provide basis for the better prevention and treatment of ROP.Methods:From May 2017 to April 2019, the preterm infants were admitted to the Neonatal Intensive Care Unit of the First Affiliated Hospital of Zhengzhou University at birth and were hospitalized for more than 2 weeks, gestational age ≤ 35 weeks and birth weight ≤ 2 500 g. They were selected as the study objects.The perinatal data including heart rate, blood pressure, patent ductus arteriosus, ventricular septal defect, and NT-proBNP level on the 1 st, 7 th and 14 th day, respectively after birth were collected.They were divided into ROP group and non ROP group according to the results of the retinopathy screening report.The influencing factors of ROP were screened out by univariate analysis and multivariate regression analysis. Results:A total of 1 119 subjects were included, 105 infants with ROP were detected, and the prevalence of ROP was 9.4%.Among them, 12 cases of pre-threshold lesion type 1 and threshold lesions required treatment, accoun-ting for 1.07% of screened preterm infants .Univariate analysis and multivariate regression analysis revealed that gestational age, birth weight, total oxygen therapy time, and intrauterine growth restriction were all factors affecting ROP, and 2 hemodynamic related indicators, such as the level of NT-proBNP in plasma on the 14 th day after birth, and placenta previa or abruption were also related to ROP( OR=0.604, 0.647, 1.276, 2.361, 1.688 and 2.506, respectively, all P<0.05). Conclusion:The hemodynamic changes in perinatal period may be involved in the formation of ROP, and it is necessary to further clarify its mechanism.