树突状细胞外泌体诱导间充质干细胞向成骨细胞分化

本研究观察人树突状细胞（dendriticcells,DC）来源的外泌体（DC—derivedexosome,DCex）对人骨髓间充质干细胞（mesenchymalstemcells,MSC）成骨分化的影响。采用超速离心法从树突状细胞培养上清中获取DCex,应用电子显微镜观察DCex形态并通过流式细胞术检测和鉴定其细胞来源。取第3代MSC,设3组培养诱导体系：①对照组：d—MEM基础培养液组;②实验组：d—MEM基础培养液＋DCex（10μg/m1）组;③α-MEM基础培养液＋标准诱导剂组。采用荧光实时定量PCR、琼脂糖凝胶电泳检测各组成骨分化转录因子Runx2mRNA的表达情况,并进行碱性磷酸酶（ALP）活性检测。另外,荧光染料DiI标记DCex,应用共聚焦显微镜观察DCex进入MSC的过程。结果显示,在电子显微镜下DCex呈典型的圆形或椭圆形膜层结构,直径为40—100nm,并表达DC细胞的标志物CD83,CD86,CD80和HLA—DR。在DCex处理MSC后6h时,可在共聚焦显微镜下观察到进入到MSC胞质内的DCex,随着作用时间延长,细胞荧光强度增加。按组培养第7天,DCex实验组Runx2表达较对照组增高,差异有统计学显著性（P〈0．05）;MSC培养第14天,DCex组ALP含量OD值与对应蛋白比为2．22±0．27,显著高于阴性对照组（1．20±0．21）（P〈0．01）,但低于标准诱导组（3．22±0．24）（P〈0．05）。结论：DCex可以促进MSC向成骨细胞分化,其且体机制仍需讲一步研穷证实．     

Possible benefits of high-dose chemotherapy and autologous stem cell transplantation for adults with recurrent medulloblastoma

In an attempt to improve the dismal prognosis of adults with recurrent medulloblastoma, six patients were treated with aggressive salvage therapy including high-dose chemotherapy (HDCT) and autologous stem cell transplantation (ASCT). At relapse, all patients underwent surgical debulking followed by HDCT/ASCT and then radiotherapy when possible. The treatment plan included two cycles of HDCT/ASCT; first with cyclophosphamide, etoposide and carboplatin (CECb) and then 2 months later with cyclophosphamide and thiotepa (CT). Three of the six patients received the planned therapy. One patient experienced severe toxicity requiring life-sustaining therapy. This patient developed multi-organ dysfunction including multiple enhancing lesions in both cerebral hemispheres that slowly resolved over several months. Two other patients did not mobilize sufficient stem cells for two ASCT procedures. They received one ASCT conditioned with cyclophosphamide, thiotepa and carboplatin (CTCb). Three of six patients had a complete response (CR); the other three had a partial response (PR). Following the first ASCT, median duration of response was 13.5 months (range 9-29 months) and median survival was 21.5 months (range 12-42 months). There was no treatment-related mortality. We conclude that HDCT/ASCT with CECb-CT or CTCb is active against recurrent medulloblastoma in adults and may be associated with prolonged remissions. Multiple enhancing cerebral lesions on brain MRI early post-HDCT/ASCT may be a consequence of the treatment rather than metastatic disease.     

Effect of different doses of furazolidone with amoxicillin and omeprazole on eradication of Helicobacter pylori

BACKGROUND: Resistance to metronidazole is one of the most common reasons for Helicobacter pylori treatment failure with classic triple therapy. In contrast, the clarithromycin-based regimen is not cost-effective for developing countries. Furazolidone is a very good substitute for metronidazole and clarithromycin, but its many side-effects limit widespread use. The aim of the present study was to assess the efficacy of two different doses of furazolidone in combination with amoxycillin and omeprazole. METHODS: A total of 123 patients with duodenal ulcer were randomized and received the following medications for two weeks. Group A: furazolidone 2 x 200 mg + amoxycillin 2 x 1 g + omeprazole 2 x 20 mg/day. Group B: furazolidone 2 x 50 mg + amoxycillin 2 x 1 g + omeprazole 2 x 20 mg/day. Control endoscopy was performed after 6 weeks and two biopsy specimens from the antrum and two from the corpus were taken for a urease test and histology. Eradication was concluded if all tests were negative for H. pylori. RESULTS: In total, 110 patients completed the study. Four patients in group A did not tolerate the regimen on day 8 of therapy and were excluded from the study. Serious complications such as fever, and fatigue and dizziness, which occurred in the beginning of the second week of treatment (days 8-10), were more common in group A than in group B (19%, 15.9% and 14.3%, respectively, in group A vs 0% in group B). The eradication rate by per protocol analysis was significantly higher in group A than in group B (88.9%vs 67.9%, respectively, P = 0.008). However, this difference was low and not statistically significant by intention-to-treat analysis (76.2% in group A and 62.3% in group B, P = 0.09). CONCLUSION: The regimen with a non-reduced dose of furazolidone in combination with amoxycillin and omeprazole was effective when the patients tolerated the drugs and completed the study.     

Extra-curricular supervised training at an academic hospital: is 200 hours the threshold for medical students to perform well in an emergency room?

Introduction

Due to high number of jobs in Emergency Medicine (EM) and the lack of specialist to work in this field, recent graduates work in the emergency room straight after medical school. Additional courses on EM are available through Academic Leagues. This organizations offer lectures and supervised extra-curricular practical activities in their teaching university-affiliated hospital. The objectives of the present study are to assess the influence of hours undertaken in the extra-curricular practical activities on the performance and confidence of students in carrying out the different procedures in the emergency department, and on their own perception of how well they did. Also, to assess the influence the practical activities have on student´s future choice of specialty.

Methods

A Cross-sectional study conducted by collecting data through a questionnaire. 102 eligible individuals were included and divided into two groups according to the number of extra-curricular hours performed (Group 1- up to 200 hours and Group 2- over 200 hours).

Results

Students in Group 2 (over 200 hours) had a greater number of procedures performed on all variables evaluated, in particular, initial patient care (mean 363.8 vs.136.905 in Group 1 - p = 0.001), Simple Sutures (mean of 96.2 vs 33.980 respectively) ( p = 0.00003). To determine patient follow-up by the student, the number of initial patient care was correlated with number of discharge procedures performed (in Group 1, 49.6% of patients were not followed up and discharged by the same students who first talked to them in the hospital. While in Group 2, this value becomes 29.4 % - values for Group 1 - p = 0.011 and Group 2 - p = 0.117). Regarding the influence of the practical extra-curricular activities, 76.5% of the total reported that it had influenced their choice of future specialty.

Conclusions

The aptitude, confidence and skill of students are closely linked to the practice time (number of training hours served). Two hundred hours appeared to be a relatively significant time for the student to demonstrate good conduct and ability. Practical extra-curricular activities had the ability to influence the future choice of specialty, either positively or negatively.