Objective:To investigate the effects of riboflavin-ultraviolet A scleral collagen cross-linking on the retina under different irradiation time, and to determine the safe irradiation time.Methods:Sixty healthy New Zealand white rabbits were randomly divided into control group (0 minute group), 10 minutes group, 20 minutes group, 30 minutes group and 40 minutes irradiation group according to the irradiation time, with 12 rabbits in each group.The left eye was irradiated with riboflavin-ultraviolet A scleral collagen (370 nm, 10 mW/cm 2). The histopathological change of retina was observed by light microscope and transmission electron microscope and compared among different groups.The concentration of MDA and the activities of SOD, CAT and GSH-Px in retinal tissue were detected by corresponding kits.The expression levels of SOD and CAT proteins in retinal tissue were detected by Western blot method.The study protocol was approved by the Binzhou Medical University Laboratory Animal Ethical Committee (No.2017-80). The use and care of animals complied with the statement of ARVO and the Regulation on the Management of Laboratory Animal Quality of China. Results:Under the light microscope, the structure of the retinas in the control group was orderly arranged.Under the transmission electron microscope, the lamellar structure in the inner segment and the mitochondrial structure in the outer segment of the photoreceptor cells were intact, and the mitochondrial ridge was continuous in the control group.There was no obvious difference in retinal morphology between the 10 minutes irradiation group and the control group under both the light microscope and the transmission electron microscope, and the retinal damage became more severe with the prolongation of irradiation time.The concentration of MDA in the retina of each group was elevated gradually with the increase of irradiation time, and the difference was statistically significant ( F=65.25, P<0.05). The concentration of MDA was (11.31±1.84), (14.94±1.04)and (18.25±1.42)nmol/mgprot in the 20 minutes, 30 minutes and 40 minutes irradiation groups respectively, which were significantly higher than (1.13±0.02)nmol/mgprot in the control group (all at P<0.05). The MDA concentration in 20 minutes, 30 minutes and 40 minutes irradiation groups was increased successively, showing statistically significant differences (all at P<0.05). With the prolongation of irradiation time, the activities of SOD, CAT and GSH-Px as well as the expression levels of SOD and CAT proteins were significantly decreased gradually ( F=44.09, 34.18, 35.60, 115.75, 78.86; all at P<0.05). The differences between the control group and 20 minutes, 30 minutes, 40 minutes irradiation groups, and the differences among 20 minutes, 30 minutes, 40 minutes irradiation groups were statistically significant (all at P<0.05). Conclusions:Riboflavin-ultraviolet A 10 mW/cm 2 scleral collagen cross-linking irradiation for 10 minutes is safe.Excessive irradiation time can cause damage to the retina of rabits.

Objective To understand the gender selection and prognosis of children with 46,XY disorders of sex development (DSD) after surgery,and to provide reference for future clinical decision-making.Methods Data of 85 (80 males and 5 females) postoperative patients with 46,XY DSD with follow-up age of 6(4,11) years who were treated at the Department of Endocrinology,Genetics and Metabolism of Beijing Children's Hospital Affiliated to Capital Medical University during the period from September 2009 to April 2018 were retrospectively analyzed.The patients were grouped based on diagnosis.The basis of postoperative gender selection,patient satisfaction and related factors,gender characteristics,and adolescent development were analyzed.The Pre-school Activities Inventory or the Children's Sex Role Inventory were used in the analysis of gender tendency.Mann-Whitney U test was used to compare postoperative gender satisfaction of different factors.The Kruskal-Wallis method was used to compare the postoperative gender satisfaction of each group.Fisher's test was used to compare the follow-up status of male children over 11 years old in each group.Results Among the 85 patients,62 individuals were raised as girls after birth,9 were facultative and 14 as boys.According to the diagnosis,there were 31 individuals in group 1 (with 5α-reductase deficiency),11 individuals in group 2 (with androgen insensitivity syndrome),9 individuals in group 3 (with NR5A1 gene mutation),4 individuals in group 4 (with hypergonadotropic gonadal dysplasia),and 30 indiviudals in group 5 (with unclear diagnosis and normal human choionic gonadotophin test).Among the 71 children who were raised as girls or facultative children after birth,66 selected as boys,and 5 continued as girls (among them,3 individuals were female with passive selection,and 2 individuals of testicular dysplasia with uterus in group 4 and 5 were female with active selection).Among the 71 patients faced with gender selection,only one was unsatisfied,that was a postoperative female.There was no significant difference in postoperative gender satisfaction among different disease diagnoses,surgical age and penis length (x2(H)=6.007,P=0.199;Z=-0.860,P=0.390;Z=-0.438,P=0.661).Fifty-nine of the 85 cases completed the gender tendency scale test and 46 cases (78％) were consistent.In the male patients,45 cases were consistent.Thirteen inconsistent patients (22％) were female or facultative after birth who were 5 years old or older.There was no stigmatization noticed in the inconsistent patients' daily life and school social settings.There were 22 male patients aged 11 years and older.They were 13(12,16) years old.Fourteen (64％) individuals' penile length reached the normal minimum,15 (68％) individuals' testicular volume were equal or more than 4 ml,16 (73％) individuals' sex hormones entered puberty levels,12 (55％) individuals had been spermatorrhea,the age of first spermatorrhea was (13.3±2.4) years.They were satisfied and adaptable after surgery.There was no significant difference in the above indicators among the groups (x2 =2.999,P=0.694;x2 =7.278,P=0.086;x2 =5.597,P=0.358;x2 =6.904,P=0.127).Conclusions The appropriate gender of 46,XY DSD patients was selected according to gonadal status after diagnosis.Regardless the diagnosis,the age of operation and the length of the penis at the first diagnosis,male patients were satisfied with the gender after the operation.A few of patients were inconsistent with the results of gender tendency scale test who were raised as girls or facultative children after birth,and they required sustained special attention.Some of the children showed natural adolescent development in males,and the prognosis may be ideal.