Problem-based and student-centered learning patten brings new challenges to the both sides of teaching and learning.Clinical probation is the first step of medical students.The problem-based learning patten is used to clinical probation and achieves good results.It helps to improve medical students' quality and should be applied in China medical education.

Objective To study the effect of high-glucose-high-fat diet on expression and methylation of insulin receptor ( INSR) gene in F1 offspring. Methods Sixty 5-week-old male SD rats were randomly divided into two groups:normal diet group and high-glucose-high-fat diet group. After rats were fed for three months, all male rats were performed to copulate with normal female rats. The body weight, blood glucose, and blood insulin of neonatal rats of F1 offspring were measured. The genome DNA, total RNA, and total protein were extracted from livers, brains, and muscles of neonatal rats. Relative expression of INSR in both mRNA level and protein level were detected using a realtime PCR test and a Western blot test respectively. Methylation of INSR promoter was analyzed by a methylation specific PCR ( MSP ) . Results Both body weight and fasting glucose were without significant difference in two groups. In high-glucose-high-fat diet group, both the glucose tolerance and insulin tolerance of neonatal rats in F1 offspring were significantly decreased. Except that in brains, the expressions of INSR gene in livers and in muscles of neonatal rats in high-glucose-high-fat diet group were down-regulated in mRNA ( realtime PCR ) and protein levels ( Western blot) compared to the normal diet group. Meanwhile, the methylation of INSR gene in livers and muscles were strengthened in high-glucose-high-fat diet group. Conclusion A high-glucose-high-fat diet fed to male SD rats leads to the decrease in glucose tolerance, insulin tolerance, and the inhibition of expression of hepatic and muscle INSR gene in neonatal offspring. The methylation of INSR gene could be involved in this phenomenon.

Objective To study the effects of discoidin domain receptor 1 (DDR1) mediated phosphorylation of protein Tau on hypoxic-ischemic brain damage (HIBD) in neonatal rats and its possible mechanism.Methods Sixty-four seven-day-old male specific-pathogen-free Wistar rats were randomly divided into four groups with sixteen in each: Sham, HIBD, HIBD with normal saline (HIBD+NS) and HIBD with DDR1 inhibitor (HIBD+DI) groups. A rat model of HIBD was established by subjecting the rats to left common carotid artery ligation, followed by exposing them to hypoxia for two hours. In HIBD+DI group, the inhibitor of DDR1 was immediately injected into lateral cerebroventricles of the rats following modeling. Forty-eight hours after injection, tissues of left cerebral cortex were collected from each rat to evaluate histopathological changes with HE staining. Western-blotting was used to assess the phosphorylation levels of DDR1 and protein Tau. Enzyme-linked immunosorbent assay was performed to detect the concentrations of acetylcholine. Analysis of variance ort test were used for statistical analysis.Results (1) Damages in cerebral cortex: Percentages of abnormal neurons in the rats of HIBD group were higher than those in Sham group [(80.28±4.51)% vs (10.40±2.17)%,t=39.491,P<0.01]. Pyknotic or necrotic neurons in the rats of HIBD+DI group were less than those in HIBD+NS group [(31.91±3.05)% vs (82.01±7.20)%,t=18.123,P<0.01]. (2) Phosphorylation of DDR1 and protein Tau: Levels of phosphorylated DDR1 in the cerebral cortexes of rats in HIBD group were higher than those in Sham group (0.922±0.199 vs 0.095±0.023,t=10.379,P<0.01), and those levels in HIBD+NS group were higher than those in HIBD+DI group (1.200±0.171 vs 0.255±0.111,t=11.901, P<0.01). The phosphorylation of protein Tau was similar to that of DDR1 (0.919±0.228 vs 0.194±0.224 in HIBD and Sham groups,t=7.347; 1.100±0.167 vs 0.291±0.210 in HIBD+NS and HIBD+DI groups,t=9.447;bothP<0.01). (3) Levels of acetylcholine: Levels of acetylcholine in cerebral cortexes of rats in HIBD group were lower than those in Sham group [(3.685±0.472) vs (7.429±0.861) ng/g protein,t=10.781,P<0.01], and that levels in HIBD+DI group were higher than those in HIBD+NS group [(7.058±0.915) vs (2.521±0.723) ng/g protein,t=10.989,P<0.01].Conclusions Activation of DDR1 plays a key role in enhancing the phosphorylation of protein Tau and in reducing the secretion of acetylcholine in cerebral cortexes of rats with HIBD. Inhibitor of DDR1 could protect neonatal rats from HIBD through the decreasing of protein Tau phosphorylation and increasing of acetylcholine release by inhibiting the activation of DDR1.

Objective: To explore trends of adolescent induced abortion in Guangzhou, and to provide a reference for female adolescents induced abortion prevention and reproductive health promotion. Methods: A retrospective survey was conducted to collect information regarding basic characteristics, frequency of induced abortion and risk factors of 7 648 adolescents aged 12-24 years who received induced abortion in one maternal and child health care hospital during 2015 to 2019. Chi square test and trend analysis were carried out for data analysis. Results: Adolescents with first pregnancy, nulliparity and first abortion accounted for 61.28 %, 81.63%, 71.82%, respectively; a total of 1 251 adolescents aged 12-19 had induced abortion, accounting for 16.36%, and 6 397 adolescents aged 20-24 had induced abortion, accounting for 83.64%, the number of pregnancy, parity, and induced abortion in aged 20-24 was higher than that in the aged 12-19, and the differences were statistically significant ( P ＜0.05). The proportion of the aged 12-19 showed an overall downward trend in each year, while that of aged 20-24 showed an overall upward trend, and there was a statistically significant difference between the two groups ( χ 2 trend =22.99, P <0.01); the first pregnancy accounted for 61.28 %, and the number of pregnancies showed an overall upward trend ( χ 2 trend =9.06, P <0.05). The proportion of repeated abortion did not increase significantly, but the proportion of recurrent repeated abortion (within one year) showed an upward trend ( χ 2 trend = 6.69, P <0.05). The proportion of adolescents with reproductive tract infection showed a downward trend ( χ 2 trend =4.91, P < 0.01 ). Conclusion The proportion of induced abortion in first pregnancy and nulliparrous female adolescents is relatively high and showed an upward trend, which may be related to insufficient reproductive health knowledge and the lack of reproductive health education from society, school and family. Necessary resources should be devoted to adolescents with recurrent repeated abortion, as well as adolescent reproductive health education, post abortion and medical care, the decrease in the rate of reproductive tract infection in adolescents suggests that the awareness of reproductive tract infection prevention has been improved.

Objective To study the effect of perinatal hypothyroidism (PHT) on hippocampal neuronal structure and function of neonatal rats.Methods Sixteen pregnant SD rats were randomly divided into control group and PHT group (n=8).The pregnant rats were subjected to gavage by normal saline or 6-propyl-2-thiouracil (PTU) every day from 15 d of pregnant to the end of lactation.After parturition,38 male neonatal rats from each group were chosen for the following study.On the 7th d of birth,15 neonatal rats from each group were sacrificed,and the concentrations of free triiodothyronine (FT) 3,FT4 and thyroid stimulating hormone (TSH) in serum and acetylcholine (Ach) in the hippocampus were detected by ELISA.Real-time PCR,Western blotting and immunohistochemistry were used to assess the expressions of neuronal nuclei antigen (NeuN) and microtubule-associated protein tau (MAPT)in transcriptional and protein levels orderly.The left neonatal rats at one month old were performed morris water maze test to evaluate the learning and memory abilities.Results ELISA results showed that both FT3 and FT4 significantly decreased but TSH increased significantly in serum of PHT rats as compared with those in the control group (P＜0.05);Ach in the hippocampus of PHT rats was reduced three folds as compared with those in control group,with significant difference (P＜0.05).Real-time PCR and Western blotting results showed that the mRNA and protein expression levels of NeuN and MAPT in PHT rats were markedly down-regulated as compared with those in the control group:0.25 and 0.12 fold ofmRNA level in control group,and 0.35 and 0.22 fold of protein level in control group,with significant differences (P＜0.05).Immunohistochemistry indicated decreased NeuN and MAPT expression levels of varying degrees in PHT rats.In the morris water maze,one-month-old rats with PHT showed significantly prolonged escape latency ([10.18±3.02] s) and lengthened total distance ([365.28±41.77] cm) as compared with the control rats ([24.36±5.15] s,[790.36±72.53] cm,P＜0.05).Conclusion PHT could result in reduced expressions of neuron markers,axons dysfunction and decreased secretion of neurotransmitter in the hippocampus of neonatal rats,and it could weaken the learning and memory abilities in long term.

Objective To study the effect of miR-146a on hepatic INSR gene expression in F1 offspring of paternal rats with high-glucose-high-fat diet ( HGFD) . Methods 5-week-old male SD rats were randomly divided into normal diet ( ND) and HGFD groups. Male rats with ND or HGFD feeding for three months mated with normal female ones. Blood glucose concentration, glucose tolerance, and insulin tolerance in newborn male offspring rats were detected respectively. Differential miRNAs between ND and HGFD groups were compared using next generation sequencing and were then confirmed by real-time quantitative PCR ( qPCR) . The relative expression of INSR mRNA and the methylation level of INSR promoter in liver tissues of the offspring newborn rat were detected and the correlations between them and the relative expression of differential microRNA were analyzed respectively. In vitro, effects of miR-146a on expression and methylation of INSR gene in BRL-3A cells were detected using Western-blot assay and qPCR respectively. Results The fasting glucose concentration of different groups were without significant difference, but glucose tolerance and insulin tolerance of neonatal male rats in HGFD group were decreased significantly . Next generation sequencing has revealed 45 up-regulated miRNAs and 15 down-regulated miRNAs in HGFD group. Among them, differences of 8 miRNAs expression in the enlarged samples were confirmed by qPCR. miR-146a was up-regulated for more than 10 times in the liver of the offspring of HGFD group. Expression level of miRNA-146a was negatively correlated with the relative expression of INSR and positively correlated with the methylation level of INSR in livers of neonatal rats in HGFD group. In vitro, miR-146a ( mimics ) promoted the methylation of INSR gene and inhibited the expression of INSR in BRL-3A cells. Conclusion HGFD feeding to male SD rats leads to the inhibition of hepatic INSR gene expression in neonatal offspring via upregulating miR-146a.

Objective:To investigate the pathogenesis, precaution and treatment of neonatal congenital complete heart block (CCHB) in twins.Methods:The clinical data of a case of premature twins with neonatal CCHB from the Department of Neonatology, the First Affiliated Hospital of Xinxiang Medical University were retrospectively analyzed and related literature was reviewed.Results:(1)Case review: the 37-year-old gravida had no symptoms.Fetal ultrasound cardiogram(fUCG)at 23 weeks of gestation indicated bradycardia and CCHB.Then, the mother was diagnosed with undifferentiated connective tissue disease.After treatment with human immunoglobulin, dexamethasone and hydroxychloroquine, fUCG at 31 weeks of gestation still suggested CCHB.An emergency cesarean section was performed on the diagnosis of threatened preterm labor.With weakly positive neonatal antinuclear antibody (ANA), and positive Ro60 and Ro52 autoantibodies, twins were diagnosed with CCHB by 24 hour-Holter monitors.One of the twins was discharged with CCHB (ventricular rate of 80-90 times/min) after systemic therapy, but the weight increased to 2 200 g. The other one of the twins suffered from the sudden decrease of heart rate and blood pressure and finally died of sudden cardiac arrest.(2) Literature search: two cases in Chinese and 9 cases in English were reviewed.Among them, 9 cases were sjogren syndrome type A (SSA)/Ro and sjogren syndrome type B(SSB)/La related CCHB, and 2 cases were idiopathic CCHB.Conclusions:The placental transfer of anti-SSA or anti-SSB is an important mechanism of neonatal CCHB in twins, and other factors may also be involved.Current treatments are unsatisfactory.Most patients need pacemaker implantation.Early diagnosis and prenatal management can improve the prognosis.

Objective To investigate the prevalence of iron deficiency(ID)and iron deficiency anemia (IDA) in pregnant women in urban areas of China. Methods The study was a national cross-sectional survey conducted from September 19th, 2016 to November 20th, 2016. According to the classification of the National Bureau of Statistics, all survey sites were set up in 6 regions of the country. Pregnant women were continuously selected using multistage stratified sampling. A total of 12 403 pregnant women were collected and examined for serum ferritin and hemoglobin levels. Results The median serum ferritin level during pregnancy was 20.60 μg/L(11.78-36.98 μg/L), the hemoglobin level was(118±12)g/L. With the progress of pregnancy, the levels of serum ferritin and hemoglobin decreased gradually. The median serum ferritin levels in the first, second trimester and third trimester were 54.30 μg/L(34.48-94.01 μg/L), 28.60 μg/L(16.40-50.52 μg/L), and 16.70 μg/L(10.20-27.00 μg/L)respectively(P<0.01). The mean hemoglobin levels were(127 ± 10)g/L,(119 ± 11)g/L and(117 ± 11)g/L respectively(P<0.01). The prevalence of ID in urban pregnant women was 48.16%(5 973/12 403), and IDA prevalence was 13.87% (1 720/12 403). The prevalence of IDA in the first, second trimester and third trimester were 1.96% (20/1 019), 8.40%(293/3 487)and 17.82%(1 407/7 897), respectively(P<0.01). The prevalence of standardized ID and IDA were significantly different in various regions of China(P<0.01). The standardized prevalence of ID were relatively higher in East China and Northeast China, 57.37% and 53.41% respectively, while it was the lowest in Southwest China, 30.51%. The standardized prevalence of IDA in South Central, Northwest, and East China were relatively high, 21.30%, 16.97% and 17.53% respectively, and the standardized prevalence of IDA in Southwest China was the lowest, 5.44%,the differents in various regions were significant(all P<0.01). Conclusion The current phenomenon of ID and IDA in pregnant women is still very common,and nutrition and health care during pregnancy should be strengthened.