Three-dimensional modeling in anatomy-Tool or terror?

Three-dimensional (3D) modeling is a recent, innovative approach to teaching anatomy. There is little literature, however, to suggest how 3D modeling is best used to teach students and whether or not students can gain the same level of understanding as they might use more traditional, hands-on, teaching methods. This study evaluated the use of a 3D modeling software in both a flipped classroom curriculum and as an active learning tool in comparison to traditional, physical model-based teaching. Pre- and post-course content-based assessments were used to evaluate students' learning. Our findings indicated no significant difference between standard and flipped classroom learning; however, the students who used 3D modeling software as an active learning tool significantly underperformed students in the standard group (F(2,1060) = 112.43, p < 0.0001). These findings suggest that these technologies may not yet be useful as a primary means of instruction. Possible explanations may include cognitive overload in navigating the system, intrinsic limitations of the software, or other factors. Further development and research of these technologies is necessary prior to their adoption into teaching practices in anatomy.

Ultrasound as a Learning Tool in Bachelor-Level Anatomy Education.

Point of care ultrasound (POCUS) has become an increasingly common diagnostic tool in the clinical environment. As a result, it is being used earlier for medical students in Undergraduate Medical Education (UME) as a learning tool for the basic sciences including gross anatomy. There is little literature, however, to support its utility for basic science education in students currently seeking a bachelor's degree. This study consisted of fourteen currently enrolled bachelor students with previous instruction in human anatomy and physiology. Students participated in an ultrasound didactic and an interactive ultrasound experience with volunteers. Before and after this session, students were asked to complete an assessment measuring their spatial understanding of the human anatomy and their ability to locate structures using ultrasound. Wilcoxon's signed-rank tests comparing assessment scores showed significant improvement on both portions of the assessment. Based on this improvement, we suggest that ultrasound is a valid educational tool which can be used at the bachelor-level to effectively enhance students' learning of anatomy and provide hands on experience with modern technology. Further research with larger samples will be necessary to determine whether it would supplement or replace more traditional teaching modalities.

Inter-Observer Variability in the Interpretation of Endoscopic Mucosal Resection Specimens of Esophageal Adenocarcinoma: Interpretation of ER specimens.

INTRODUCTION: Endoscopic resection (ER) has revolutionized the staging and therapy of superficial esophageal adenocarcinoma. Pathologic evaluation allows an assessment of the risk of lymph node metastases based on tumor characteristics. The aim of this study was to assess the inter-observer variability in pathologic assessment of ER specimens of esophageal adenocarcinoma. METHODS: We performed a retrospective study on ER specimens of superficial esophageal adenocarcinoma from four US institutions. Original endoscopic resection slides were re-reviewed by two blinded, experienced (study) gastrointestinal pathologists for the depth of tumor invasion, tumor grade, and the presence of lymphovascular invasion (LVI). Discordance was considered present only when both study pathologists disagreed with the original report. RESULTS: There were 25 ER specimens reviewed for this study, and discordance occurred in 12 of the 25 specimens (48%) for the depth of tumor invasion. In most cases (83%), the discordance was related to overstaging a true T1a lesion. We found that only 38% of true T1a lesions were correctly staged for depth of invasion. Less commonly discordance was secondary to understaging a true T1b lesion. There was concordance between the two study pathologists in 22/25 cases (88%) on the depth of invasion. Discordance was present for tumor grade in 8/18 cases (44%) and for LVI in 4/16 cases (25%). Concordance between the study pathologists was 80% for tumor grade and 88% for LVI. CONCLUSIONS: There was an alarmingly high rate of discordance (48%) between the study pathologists and the original pathology assessment for the depth of tumor invasion in ER specimens. This was particularly common for lesions called T1b on the original pathology report. Since critical decisions are made regarding esophageal preservation or esophagectomy on the basis of the pathologic interpretations of ER specimens, it behooves surgeons to understand the inter-observer variability. Review of ER specimens by an experienced GI pathologist is recommended to ensure that patients receive the appropriate treatment for superficial esophageal adenocarcinoma.

The Durability of Endoscopic Therapy for Treatment of Barrett's Metaplasia, Dysplasia, and Mucosal Cancer After Nissen Fundoplication.

INTRODUCTION: Radiofrequency ablation (RFA) ± endoscopic resection (EMR) is an established treatment strategy for neoplastic Barrett's and intramucosal cancer. Most patients are managed with proton pump inhibitors. The incidence of recurrent Barrett's metaplasia, dysplasia, or cancer after complete eradication is up to 43 % using this strategy. We hypothesize the addition of fundoplication should result in a lower recurrence rates after complete eradication. METHODS: Multi-institutional retrospective review of patients undergoing endotherapy followed by Nissen fundoplication RESULTS: A total of 49 patients underwent RFA ± EMR followed by Nissen fundoplication. Complete remission of intestinal metaplasia (CR-IM) was achieved in 26 (53 %) patients, complete remission of dysplasia (CR-D) in 16 (33 %) patients, and 7 (14 %) had persistent neoplastic Barrett's. After fundoplication, 18/26 (70 %) remained in CR-IM. An additional 10/16 CR-D achieved CR-IM and 4/7 with persistent dysplasia achieved CR-IM. One patient progressed to LGD while no patient developed HGD or cancer. CONCLUSION: Endoscopic therapy for Barrett's dysplasia and/or intramucosal cancer followed by fundoplication results in similar durability of CR-IM to patients being managed with PPIs alone after endoscopic therapy. However, fundoplication may be superior in preventing further progression of disease and the development of cancer. Fundoplication is an important strategy to achieve and maintain CR-IM, and facilitate eradication of persistent dysplasia.

Perturbation of retinoic acid (RA)-mediated limb development suggests a role for diminished RA signaling in the teratogenesis of ethanol.

BACKGROUND: A proposed mechanism for ethanol teratogenicity entails ethanol-mediated reductions in retinoic acid (RA). This premise was investigated utilizing a mouse model, with limb reduction defects as the teratogenic end point. METHODS: Ethanol, Disulfiram, or BMS-189453 was administered to C57BL/6J mice on the 9(th) day of pregnancy. Forelimb morphology was assessed on gestation day 18 using Alcian blue and Alizarin red staining. Nile blue sulfate or LysoTracker Red (LTR) vital staining identified cell death in the limb bud. The ability of RA to prevent ethanol-induced cell death was assessed by coadministration followed by laser scanning confocal microscopic examination of LTR-staining. In situ hybridization and qPCR were used to examine gene expression in treated limb buds. RESULTS: Ethanol, Disulfiram, and BMS-189453 resulted in postaxial ectrodactyly, intermediate ectrodactyly, and other digital defects. Excessive Nile blue sulfate staining was evident in the presumptive AER following each of the three exposures. Ethanol-induced LTR staining was prevented by RA supplementation. Both in situ hybridization and qPCR illustrated decreases in Shh and Tbx5 in ethanol-exposed embryos as compared to control. CONCLUSIONS: Contrary to studies of prolonged RA deficiency, acute exposure to functional antagonists of RA results in limb defects that are morphologically similar to those caused by ethanol. The rescue of ethanol-induced cell death by RA and similar changes in Shh transcription further suggest that RA contributes to ethanol-induced limb dysmorphology. Moreover, the repression of key mediators of limb development soon after ethanol exposure adds to the existing knowledge of the pathogenic effects of ethanol.

Effects of ethanol and hydrogen peroxide on mouse limb bud mesenchyme differentiation and cell death.

Many of the morphological defects associated with embryonic alcohol exposure are a result of cell death. During limb development, ethanol administration produces cell death in the limb and digital defects, including postaxial ectrodactyly. Because an accumulation of reactive oxygen species (ROS) is produced in adult and embryonic tissues by ethanol exposure, this investigation examines the possibility that ethanol-induced cell death in the limb is a result of ROS. Using an in vitro primary culture of limb mesenchyme, the effects of hydrogen peroxide (H2O2) and ethanol on cell death and differentiation were examined. In addition, a dichlorofluorescein diacetate assay was performed to determine the relative intracellular ROS levels after exposure to several concentrations of ethanol and H2O2. Exposure of 1 to 100 microM H2O2 resulted in a 1.08-1.21 times control increase in cartilage matrix accumulation. Cell death was increased 1.69-2.76 times the untreated control value. Production of ROS ranged from 1.25-1.51 times untreated controls. Ethanol exposure of 0.25 to 1.00% (v/v) did not affect cartilage matrix accumulation but resulted in an increase of cell death (1.45-2.31 times untreated control). Intracellular ROS levels after ethanol exposure increased 1.08-1.15 times control but were lower than that produced by 1 microM H2O2. On the basis of the correlation between ROS level produced by H2O2, it was concluded that ethanol-induced cell death in limb mesenchyme is a result of a non-ROS-mediated mechanism. Therefore, in addition to ethanol-induced cell death mediated by ROS reported in the literature, ethanol-induced cell death can be induced in limb mesenchyme by mechanisms that are not dependent upon ROS.