225 research outputs found

    Standardized and quality-assured video-recorded examination in undergraduate education: informed consent prior to surgery

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    AbstractBackgroundCommunication skills combined with specialized knowledge are fundamental to the doctor–patient relationship in surgery. During a single-station video-recorded objective structured clinical examination (VOSCE), students were tasked with obtaining informed consent. Our aim was to develop a standardized and quality-assured assessment method in undergraduate education.MethodsOne hundred fifty-five students in their fifth year of medical school (78 videos) participated in a summative VOSCE within the framework of the teaching module β€œOperative Medicine.” They prepared for three clinical scenarios and the surgical procedures involved. The examination comprised participants having to obtain informed consent from simulated patients, video recording their performance. Students were assessed by two independent raters, the background of one of whom was nonsurgical. Results were statistically tested using SPSS.ResultsStudents' scores were all beyond the pass mark of 70%, averaging 91.0% (Β±4.0%), 88.4% (Β±4.4%), and 87.0% (Β±4.7%) for the appendectomy, cholecystectomy, and inguinal hernia repair checklist, respectively. Most items (68%–89% of the checklists) were found to have fair to excellent discrimination values. Cronbach's Ξ± values ranged between 0.565 and 0.605 for the individual checklists. Interrater agreement was strong (Pearson correlation coefficientΒ =Β 0.80, PΒ <Β 0.01; intraclass correlation coefficient 2.1Β =Β 0.78).ConclusionsThe VOSCE is both feasible and reliable as a method of assessing student communication skills and the application of clinical knowledge while obtaining informed consent in surgery. This method is efficient (flexible rating outside normal working hours possible with reductions in administrative load) and may be used for high-stakes evaluation of student performance

    Impact of RNA degradation on gene expression profiling

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    <p>Abstract</p> <p>Background</p> <p>Gene expression profiling is a highly sensitive technique which is used for profiling tumor samples for medical prognosis. RNA quality and degradation influence the analysis results of gene expression profiles. The impact of this influence on the profiles and its medical impact is not fully understood. As patient samples are very valuable for clinical studies, it is necessary to establish criteria for the RNA quality to be able to use these samples in later analysis.</p> <p>Methods</p> <p>To investigate the effects of RNA integrity on gene expression profiling, whole genome expression arrays were used. We used tumor biopsies from patients diagnosed with locally advanced rectal cancer. To simulate degradation, the isolated total RNA of all patients was subjected to heat-induced degradation in a time-dependent manner. Expression profiling was then performed and data were analyzed bioinformatically to assess the differences.</p> <p>Results</p> <p>The differences introduced by RNA degradation were largely outweighed by the biological differences between the patients. Only a relatively small number of probes (275 out of 41,000) show a significant effect due to degradation. The genes that show the strongest effect due to RNA degradation were, especially, those with short mRNAs and probe positions near the 5' end.</p> <p>Conclusions</p> <p>Degraded RNA from tumor samples (RIN > 5) can still be used to perform gene expression analysis. A much higher biological variance between patients is observed compared to the effect that is imposed by degradation of RNA. Nevertheless there are genes, very short ones and those with the probe binding side close to the 5' end that should be excluded from gene expression analysis when working with degraded RNA. These results are limited to the Agilent 44 k microarray platform and should be carefully interpreted when transferring to other settings.</p

    DPEP1 Inhibits Tumor Cell Invasiveness, Enhances Chemosensitivity and Predicts Clinical Outcome in Pancreatic Ductal Adenocarcinoma

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    Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers worldwide. To identify biologically relevant genes with prognostic and therapeutic significance in PDAC, we first performed the microarray gene-expression profiling in 45 matching pairs of tumor and adjacent non-tumor tissues from resected PDAC cases. We identified 36 genes that were associated with patient outcome and also differentially expressed in tumors as compared with adjacent non-tumor tissues in microarray analysis. Further evaluation in an independent validation cohort (Nβ€Š=β€Š27) confirmed that DPEP1 (dipeptidase 1) expression was decreased (T: N ratio ∼0.1, P<0.01) in tumors as compared with non-tumor tissues. DPEP1 gene expression was negatively correlated with histological grade (Spearman correlation coefficientβ€Š=β€Šβˆ’0.35, Pβ€Š=β€Š0.004). Lower expression of DPEP1 in tumors was associated with poor survival (Kaplan Meier log rank) in both test cohort (Pβ€Š=β€Š0.035) and validation cohort (Pβ€Š=β€Š0.016). DPEP1 expression was independently associated with cancer-specific mortality when adjusted for tumor stage and resection margin status in both univariate (hazard ratioβ€Š=β€Š0.43, 95%CIβ€Š=β€Š0.24–0.76, Pβ€Š=β€Š0.004) and multivariate analyses (hazard ratioβ€Š=β€Š0.51, 95%CIβ€Š=β€Š0.27–0.94, Pβ€Š=β€Š0.032). We further demonstrated that overexpression of DPEP1 suppressed tumor cells invasiveness and increased sensitivity to chemotherapeutic agent Gemcitabine. Our data also showed that growth factor EGF treatment decreased DPEP1 expression and MEK1/2 inhibitor AZD6244 increased DPEP1 expression in vitro, indicating a potential mechanism for DPEP1 gene regulation. Therefore, we provide evidence that DPEP1 plays a role in pancreatic cancer aggressiveness and predicts outcome in patients with resected PDAC. In view of these findings, we propose that DPEP1 may be a candidate target in PDAC for designing improved treatments

    Stage II/III rectal cancer with intermediate response to preoperative radiochemotherapy: Do we have indications for individual risk stratification?

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    <p>Abstract</p> <p>Background</p> <p>Response to preoperative radiochemotherapy (RCT) in patients with locally advanced rectal cancer is very heterogeneous. Pathologic complete response (pCR) is accompanied by a favorable outcome. However, most patients show incomplete response. The aim of this investigation was to find indications for risk stratification in the group of intermediate responders to RCT.</p> <p>Methods</p> <p>From a prospective database of 496 patients with rectal adenocarcinoma, 107 patients with stage II/III cancers and intermediate response to preoperative 5-FU based RCT (ypT2/3 and TRG 2/3), treated within the German Rectal Cancer Trials were studied. Surgical treatment comprised curative (R0) total mesorectal excision (TME) in all cases. In 95 patients available for statistical analyses, residual transmural infiltration of the mesorectal compartment, nodal involvement and histolologic tumor grading were investigated for their prognostic impact on disease-free (DFS) and overall survival (OS).</p> <p>Results</p> <p>Residual tumor transgression into the mesorectal compartment (ypT3) did not influence DFS and OS rates (p = 0.619, p = 0.602, respectively). Nodal involvement after preoperative RCT (ypN1/2) turned out to be a valid prognostic factor with decreased DFS and OS (p = 0.0463, p = 0.0236, respectively). Persistent tumor infiltration of the mesorectum (ypT3) and histologic tumor grading of residual tumor cell clusters were strongly correlated with lymph node metastases after neoadjuvant treatment (p < 0.001).</p> <p>Conclusions</p> <p>Advanced transmural tumor invasion after RCT does not affect prognosis when curative (R0) resection is achievable. Residual nodal status is the most important predictor of individual outcome in intermediate responders to preoperative RCT. Furthermore, ypT stage and tumor grading turn out to be additional auxiliary factors. Future clinical trials for risk-adapted adjuvant therapy should be based on a synopsis of clinicopathologic parameters.</p

    Genomic imbalances in 5918 malignant epithelial tumors: an explorative meta-analysis of chromosomal CGH data

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    BACKGROUND: Chromosomal abnormalities have been associated with most human malignancies, with gains and losses on some genomic regions associated with particular entities. METHODS: Of the 15429 cases collected for the Progenetix molecular-cytogenetic database, 5918 malignant epithelial neoplasias analyzed by chromosomal Comparative Genomic Hybridization (CGH) were selected for further evaluation. For the 22 clinico-pathological entities with more than 50 cases, summary profiles for genomic imbalances were generated from case specific data and analyzed. RESULTS: With large variation in overall genomic instability, recurring genomic gains and losses were prominent. Most entities showed frequent gains involving 8q2, while gains on 20q, 1q, 3q, 5p, 7q and 17q were frequent in different entities. Loss "hot spots" included 3p, 4q, 13q, 17p and 18q among others. Related average imbalance patterns were found for clinically distinct entities, e.g. hepatocellular carcinomas (ca.) and ductal breast ca., as well as for histologically related entities (squamous cell ca. of different sites). CONCLUSION: Although considerable case-by-case variation of genomic profiles can be found by CGH in epithelial malignancies, a limited set of variously combined chromosomal imbalances may be typical for carcinogenesis. Focus on the respective regions should aid in target gene detection and pathway deduction
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