Feasibility study on developing clinical pediatrics curriculum for medical students engaged in long schooling system in the pre-clinical stage / 中华医学教育探索杂志

Objective:To analyze the feasibility of developing clinical pediatrics curriculum for pediatric students at the pre-clinical stage, and to provide a basis for the subsequent curriculum construction.Methods:A total of 90 pediatric medical students were enrolled, including pre-clinical group (G1, third semester of the second year, n=47) and the clinical clerkship group (G2, seventh semester of the fourth year, n=43). A questionnaire survey was conducted to compare the two groups from three aspects: clinical interest, learning methods and learning ability. And 24 and 20 students were randomly selected from the two groups to participate a clinical course respectively. Both of the formative evaluation and in-class test were carried out to compare the learning performance and learning effect between G1 and G2. SPSS 22.0 was used for data analysis. The counting data were described by case number and rate, and the frequency between groups was compared by chi-square test. When the chi-square test condition is not met, Fisher's exact test was performed. Normal distribution test was carried out for measurement data. Two independent sample t test was conducted for the comparison between groups of normal distribution data and Mann-Whitney U test for the comparison between groups of skewed distribution respectively. Results:There was no significant difference in clinical interest and pre-clinical interest between the two groups (Fisher's exact probability method, P=0.252, 1.000). There were partial differences in learning methods: G1 spent more time learning after class ( Z=-2.36, P=0.018), learned more in spare time ( Z=2.53, P=0.011), learned more on the homework ( P=0.020), and had a higher preview rate ( Z=-5.07, P < 0.001). There were also partial differences in learning ability: G2 had better literature retrieval ability ( χ2=10.57, P=0.001); G2 had higher scores on class and extended class performance ( t=-3.18, P=0.004; t=-10.14, P<0.001). In terms of learning effect, G2 scored higher scores on only one multiple choice question ( t=-2.46, P=0.022). Conclusion:The pediatrics students at the pre-clinical stage have certain interest and ability to receive clinical pediatrics courses. Sufficient pre-class preparation and appropriate curriculum design are helpful to the early cultivation of student's clinical thinking.

Studies on injury of endothelial cells by homocysteine / 中国病理生理杂志

AIM: This study is to detail its possible mechanisms that homocysteine (Hcy) induces injury of cultured endothelial cells.METHODS: Hcy in sequential concentrations was added into the cultured human umbilial vein endothelial cells for 24 hours in serum-free medium. The lipid peroxidation, release of LDH, cell total protein content, cell apoptosis and necrosis were assessed. RESULTS: Hcy increased the apoptosis of endothelial cells.In high Hcy concentration the cells also showed obvious injurious and necrotic morphological changes. Lipid peroxidation increased, with LDH releasing up and cell total protein content down, and they showed a positive dose-effect relationship with the Hcy concentration. All the above effects of Hcy was strengthened by low density lipoprotein (LDL) which may suggest synergetic effects of Hcy and LDL.CONCLUSION: Our results indicate that Hcy has a strong oxidizing effect, which may be one of its major mechanism for injury of EC.

Co-injury effects of homocysteine and low density lipoprotein on endothelial cell / 中国病理生理杂志

AIM:To evaluated weather homocysteine(Hcy) and low density lipoprotein(LDL) had co-effects in pathogenesis of atherosclerosis (As). METHOD: Thiobarbituric acid reactive substance (TBARS) and apoptotic cells were measured after endothelial cell(EC) being exposed commonly or separated to Hcy and LDL. RESULTS: TBARS content in Hcy +LDL group was 4.9～7.7 times of that in single Hcy or LDL group, even put together TBARS contents of single Hcy or LDL groups, the co-effect of Hcy+LDL still showed 3 times higher than the former. Furthermore, Hcy+LDL showed obvious apoptosization effect on EC. The lipid peroxidization and EC apoptosization effects of Hcy+LDL were inhibited by adding folic acid , L-arginine+folic acid or glutamate+glycine. CONCLUSION: Hcy+LDL have co-injury effects on EC which may lead to As. The pathogenic factors of these effects probably involve the thiol groups of Hcy and their injury on nitric oxide system of EC.ESULTS :TBARScontentinHcy +LDLgro

Caspase3 activity during the progress of HUVEC apoptosis induced by homocysteine / 中国病理生理杂志

AIM: In this research, the apoptosis mechanism in human umbilical vein endothelial cells (HUVEC) exposed to increasingly high Hcy concentrations was investigated by examining the intracellular signaling pathways. METHODS: HUVEC were cultured and pretreated with Hcy. Twenty-four h after Hcy treatment, cell apoptosis was detected by Annexin V and DNA ladder analysis. Caspase3 and c-IAP1/2 mRNA expression were examined using reverse transcription-polymerase chain reaction (RT-PCR) and protein expression detected by Western blotting. The activation of caspase 3 was measured with the specific substrate DEVD-AMC. RESULTS: Hcy (0.3 mmol/L) induced apoptosis of HUVEC. Caspase 3 mRNA and protein expressions increased and activation enhanced with the concentration of increasing Hcy, but c-IAP2 mRNA and protein expression decreased. CONCLUSION: Hcy induces apoptosis of HUVEC in vivo by activating caspase 3 and inhibiting protein c-IAP-2 mRNA and protein expression.