Objective To assess the protective effect of recombinant human erythropoietin (EPO) on human retinal pigment epithelial (RPE) cells injured by light. Methods Cultured human RPE cells were exposed to light for 12 hours, and the culture was stopped 24 hours later. The 3(4,5dimethylthiazole2y1)2,5diphenyl tetrazolium bromide (MTT) cell viability assay and annexin V flunorescein isothiocyanate/propidium iodium labeling and flow cytometry were used to assess the effects of EPO with different concentration on the cellular viability and apoptosis of human RPE cells. The protective effect and mechanism of EPO on RPE cells injured by light was detected by adding AG490. Results EPO, especially with the concentration of 40 IU/ml, obviously increased the cellular viability of RPE cells and apparently decrease the cellular apoptosis induced by light injury. After adding AG490, the effects of EPO on cellular viability and apoptosis were inhibited. Conclusion It is suggested that EPO can protect the human RPE cells from lightinduced injures, and its protective mechanism works after the combination of EPO and its receptor.
ObjectiveTo detect the induction of inducible nitric oxide synthase (iNOS) and nitric oxide (NO) production in immunostimulated retinal pigment epithelial (RPE) cells to seek for the supplying of the arginine, a substrate for NOS; as well as the effects of produced NO on the tight junction of RPE-J cells. MethodsRat′s RPE-J cells were treated with interferon-γ(INF-γ), tumor necrosis factor-α(TNF-α) and lipopolysaccharide (LPS), and Northern and Western blotting were applied to analyze the expression of the citrulline-NO cycle enzymes and related enzymes and the effect of dexamethasone and cyclic adenosine monophosphate (camp) on the expression of iNOS. Immunocytochemistry reaction and Western blotting were used to evaluate the effect of produced NO on the tight junctions of RPE-J cells.ResultsiNOS and argininosuccinate synthetase (AS) were highly induced at both mRNA and protection levels in immunostimulated RPE cells while arginiosuccinate lyase (AL) was not induced. NO was produced by cells after stimulation with TNFα, IFNγ and LPS. The induction of iNOS mRNA and the production of NO by these immunostimulated cells was further enhanced by cAMP. NO was produced from citrulline as well as from arginine. And the produced NO impaired the tight junction of RPE-J cells, decreased the production of tight junction related protein ZO-1.ConclusionIn activated RPE-J cells, citrullinearginine recycling is important for NO production, and the produced NO weakened the function of tight junction of RPE-J cells.(Chin J Ocul Fundus Dis, 2005,21:32-36)
ObjectiveTo briefly describe the specific contents and analyze the implementation effects of the information-based training system on neurology residents.MethodsSince February 2020, an information-based training system was carried out in the standardized training center for residents in the Department of Neurology, Xuanwu Hospital of Capital Medical University. The effect of the information-based training system was measured by comparing the numbers of training lessions and examinations, participation rates of training lessions and examinations, and mock examination results after 4 months of training of the resident trainees in Grade 2017 under the information-based training mode (n=35) with those of the resident trainees in Grade 2016 under regular face-to-face training mode (n=35). Chi-square test was used for comparison between training groups.ResultsCompared with those in Grade 2016, the number of lessons in Grade 2017 increased by 87.0% (43 vs. 23), the participation rate of lessons in Grade 2017 was higher (100.0% vs. 87.0%, P<0.001), the number of examinations in Grade 2017 increased by 87.5% (15 vs. 8), the participation rates of examinations were both 100.0%, and the pass rate of the mock examination in Grade 2017 was higher (94.3% vs. 77.1%, P=0.040).ConclusionThe training method and effect of the standardized training model of the information-based training system for resident doctors are worthy of recognition, providing a reference for medical teaching, especially for the standardized training of resident physicians.
ObjectiveTo briefly describe the specific contents of the “four-dimensional integration” standardized training model for neurology residents and analyze the implementation effects.MethodsSince September 2019, the Standard Training Center for Residents in Department of Neurology, Xuanwu Hospital of Capital Medical University trained residents under “four-dimensional integration” standardized training model, including primary knowledge teaching, basic skill training, clinical thinking training, and student group learning. The effect of the “four-dimensional integration” model was measured by comparing the midterm assessment results after four months of training of the resident trainees in Grade 2019 under the “four-dimensional integration” training mode (n=37) with those of the resident trainees in Grade 2018 under regular training mode (n=32). The midterm assessment was conducted through standardized and objective clinical examinations, including three evaluations (theory, skills, and clinical drills), and the pass rate of tests was evaluated through Fisher’s exact probability method for comparison between training groups.ResultsThere was no significant difference in the pass rate of theoretical assessment (100.0% vs. 96.9%, P=0.464) or the pass rate of Mini-Clinical Evaluation Exercise (100.0% vs. 90.6%, P=0.095) between the two groups. The pass rate of skill assessment in Grade 2019 was significantly higher than that of the students in Grade 2018 (94.6% vs. 71.9%, P=0.018).ConclusionThe “four-dimensional integration” standardized training model for neurology residents and it effect are worthy of recognition, which can provide a reference for medical teaching, especially for the standardized training of resident physicians.