Behçet's disease: Endovascular management of a ruptured peripheral arterial aneurysm

AbstractTraditionally, bypass grafts are at a high risk for thrombosis or anastomotic degeneration in patients with Behçet's disease. We report the successful deployment of a vein-covered stent across the neck of a ruptured peripheral arterial aneurysm, via a remote site access, with intermediate-term follow-up. Covered stents may represent an attractive alternative to open surgical bypass for the management of aneurysms in patients with Behçet's disease. (J Vasc Surg 2001;34:1127-9.)

Learning Task Models for Robotic Manipulation of Nonrigid Objects

As robots become more prevalent in smaller manufacturing and maintenance settings, it will become important to enable them to learn new tasks quickly without explicit programming by a human. One particularly challenging domain in robot learning is handling nonrigid objects and materials such as fluids and easily deformable parts and tools. The complexities of modeling nonrigid systems make it infeasible in general for a robot to plan its actions to perform a task by simulating their behavior, requiring an ability to learn an unknown model through experience. This experience can be gained both from a human demonstrating the way to perform a task and the robot itself performing task attempts to incrementally improve its model. Over time, as more experience is acquired, the robot should eventually obtain a model that allows it to perform the task when faced with new variations, generalizing its past experience. This dissertation explores this problem in the context of two robot tasks: pouring a specific volume of fluid into a moving container, and cleaning stains off of compliant objects. First, an approach is presented to learn the parameters of the pouring task by observing human demonstrations. The model learned from the demonstrations can then be exploited to learn how to pour new volumes with minimal extra learning effort by the robot. Second, this same task is used in development of a general approach for autonomous learning. Here, the robot takes a small set of random samples from the parameter space to build an initial task model and selects new parameters to test by building many local linear models. As more data is acquired, the robot's task performance improves substantially and it is able to very quickly find solutions to new task variations. Then another approach is shown that uses demonstrations to estimate a cost function for performing the task. This enables the robot to also learn strategy elements from how humans perform tasks. Finally, two approaches are discussed to learn the deformation model of a compliant part. A bimanual setup with two robot arms is used to hold and clean the part and the model is used to optimize the plans for both arms to reduce cleaning time and deformations. The first approach shows a black-box learning method to directly predict the part deformation when a known force is applied. The second uses a finite-element structure to represent the part, and learns the model by updating the stiffness parameters. When given a new part, the system only needs a few trials to improve quickly enough to clean new stains efficiently by predicting how much the part will deform under cleaning force

Brachial Artery Vasculitis and Associated Stenosis Presenting as Elbow Pain in a 16-Year-Old Soccer Player: A Case Report

Chronic vascular occlusion in the upper extremity can result from repetitive trauma, atherosclerosis, proximal embolic events, hypercoagulable states, and systemic diseases such as collagen vascular disease and vasculitis. Considerable functional impairment can result from these maladies; however, sometimes the condition develops slowly with minimal effect on the patient. We describe a 16-year-old soccer player with slow-progressing elbow pain and loss of range in motion caused by brachial artery vasculitis and resultant brachial arterial stenosis. Although vascular insults and lesions rarely cause chronic vascular occlusion, physicians should consider this possibility in patients with localized pain or atrophy, especially if the condition develops slowly

Effects of the COVID-19 pandemic on medical students: a multicenter quantitative study

© 2021, The Author(s). Background: The COVID-19 pandemic disrupted the United States (US) medical education system with the necessary, yet unprecedented Association of American Medical Colleges (AAMC) national recommendation to pause all student clinical rotations with in-person patient care. This study is a quantitative analysis investigating the educational and psychological effects of the pandemic on US medical students and their reactions to the AAMC recommendation in order to inform medical education policy. Methods: The authors sent a cross-sectional survey via email to medical students in their clinical training years at six medical schools during the initial peak phase of the COVID-19 pandemic. Survey questions aimed to evaluate students’ perceptions of COVID-19’s impact on medical education; ethical obligations during a pandemic; infection risk; anxiety and burnout; willingness and needed preparations to return to clinical rotations. Results: Seven hundred forty-one (29.5%) students responded. Nearly all students (93.7%) were not involved in clinical rotations with in-person patient contact at the time the study was conducted. Reactions to being removed were mixed, with 75.8% feeling this was appropriate, 34.7% guilty, 33.5% disappointed, and 27.0% relieved. Most students (74.7%) agreed the pandemic had significantly disrupted their medical education, and believed they should continue with normal clinical rotations during this pandemic (61.3%). When asked if they would accept the risk of infection with COVID-19 if they returned to the clinical setting, 83.4% agreed. Students reported the pandemic had moderate effects on their stress and anxiety levels with 84.1% of respondents feeling at least somewhat anxious. Adequate personal protective equipment (PPE) (53.5%) was the most important factor to feel safe returning to clinical rotations, followed by adequate testing for infection (19.3%) and antibody testing (16.2%). Conclusions: The COVID-19 pandemic disrupted the education of US medical students in their clinical training years. The majority of students wanted to return to clinical rotations and were willing to accept the risk of COVID-19 infection. Students were most concerned with having enough PPE if allowed to return to clinical activities

Clinical follow-up rather than duplex surveillance after carotid endarterectomy

AbstractPurpose: The value of duplex surveillance and the significance of contralateral carotid disease after endarterectomy have been assessed.Methods: Three hundred five patients were observed prospectively after carotid endarterectomy for a median time of 36 months (range, 6 to 96 months), with duplex surveillance performed at 1 day; 1 week; 3, 6, 9, and 12 months; and then each year after endarterectomy.Results: Thirty patients (10%) had ipsilateral symptoms (13 strokes, 17 transient ischemic attacks [TIAs]) at a median time of 6 months (range, 0 to 60 months). Life table analysis demonstrated that ipsilateral stroke was equally common for patients who had ≥50% restenosis (3% at 36 months) and those who did not (6% at 36 months, p > 0.5). Twenty-three patients (8%) developed symptoms (stroke 5, TIA 14) attributable to the contralateral carotid artery at a median time of 9 months (range, 0 to 36 months) after endarterectomy. By life table analysis, 40% of patients with 70% to 99%, 6% with 50% to 69%, 1% with <50% contralateral internal carotid stenosis, and 5% with contralateral carotid occlusion at the time of endarterectomy had a contralateral TIA in the 36 months after endarterectomy ( p < 0.01). However, contralateral stroke was not significantly more common for patients with severe contralateral internal carotid stenosis demonstrated at the time of endarterectomy (<50% stenosis, 0%; 50% to 69%, 3%; 70% to 99%, 7%; occlusion, 6% stroke rate at 36 months). Seven of the 32 patients who developed progression of contralateral disease had a TIA, compared with 11 of 227 patients who did not develop progression of contralateral disease ( p < 0.01). None of the 12 patients who progressed from a <70% to a 70% to 99% contralateral stenosis had a stroke.Conclusions: After carotid endarterectomy restenosis is rarely associated with symptoms; contralateral stroke is rare and is not associated with progressive internal carotid artery disease suitable for endarterectomy. This study has shown no benefit from long-term duplex surveillance after carotid endarterectomy. Selective clinical follow-up of patients who have high-grade contralateral stenoses would appear more appropriate. (J Vasc Surg 1997;25:55-63.

Werner Syndrome Protein (WRN) Regulates Cell Proliferation and the Human Papillomavirus 16 Life Cycle during Epithelial Differentiation

Human papillomaviruses recruit a host of DNA damage response factors to their viral genome to facilitate homologous recombination replication in association with the viral replication factors E1 and E2. We previously demonstrated that SIRT1 deacetylation of WRN promotes recruitment of WRN to E1-E2 replicating DNA and that WRN regulates both the levels and fidelity of E1-E2 replication. The deacetylation of WRN by SIRT1 results in an active protein able to complex with replicating DNA, but a protein that is less stable. Here, we demonstrate an inverse correlation between SIRT1 and WRN in CIN cervical lesions compared to normal control tissue, supporting our model of SIRT1 deacetylation destabilizing WRN protein. We CRISPR/Cas9 edited N/Tert-1 and N/Tert-1+HPV16 cells to knock out WRN protein expression and subjected the cells to organotypic raft cultures. In N/Tert-1 cells without WRN expression, there was enhanced basal cell proliferation, DNA damage, and thickening of the differentiated epithelium. In N/Tert-1+HPV16 cells, there was enhanced basal cell proliferation, increased DNA damage throughout the epithelium, and increased viral DNA replication. Overall, the results demonstrate that the expression of WRN is required to control the proliferation of N/Tert-1 cells and controls the HPV16 life cycle in these cells. This complements our previous data demonstrating that WRN controls the levels and fidelity of HPV16 E1-E2 DNA replication. The results describe a new role for WRN, a tumor suppressor, in controlling keratinocyte differentiation and the HPV16 life cycle