The Domain-Specific and Temperature-Dependent Protein Misfolding Phenotype of Variant Medium-Chain acyl-CoA Dehydrogenase

The implementation of expanded newborn screening programs reduced mortality and morbidity in medium-chain acyl-CoA dehydrogenase deficiency (MCADD) caused by mutations in the ACADM gene. However, the disease is still potentially fatal. Missense induced MCADD is a protein misfolding disease with a molecular loss-of-function phenotype. Here we established a comprehensive experimental setup to analyze the structural consequences of eight ACADM missense mutations (p. Ala52Val, p. Tyr67His, p. Tyr158His, p. Arg206Cys, p. Asp266Gly, p. Lys329Glu, p. Arg334Lys, p. Arg413Ser) identified after newborn screening and linked the corresponding protein misfolding phenotype to the site of side-chain replacement with respect to the domain. With fever being the crucial risk factor for metabolic decompensation of patients with MCADD, special emphasis was put on the analysis of structural and functional derangements related to thermal stress. Based on protein conformation, thermal stability and kinetic stability, the molecular phenotype in MCADD depends on the structural region that is affected by missense-induced conformational changes with the central beta-domain being particularly prone to structural derangement and destabilization. Since systematic classification of conformational derangements induced by ACADM mutations may be a helpful tool in assessing the clinical risk of patients, we scored the misfolding phenotype of the variants in comparison to p. Lys329Glu (K304E),the classical severe mutation, and p. Tyr67His (Y42H),discussed to be mild. Experiments assessing the impact of thermal stress revealed that mutations in the ACADM gene lower the temperature threshold at which MCAD loss-of-function occurs. Consequently, increased temperature as it occurs during intercurrent infections, significantly increases the risk of further conformational derangement and loss of function of the MCAD enzyme explaining the life-threatening clinical courses observed during fever episodes. Early and aggressive antipyretic treatment thus may be life-saving in patients suffering from MCADD

Agonists of proteinase-activated receptor-2 affect transendothelial migration and apoptosis of human neutrophils

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73837/1/j.1600-0625.2007.00605.x.pd

Emergency Management and Tourism Stakeholder Responses to Crises: A Global Survey

This paper examines the contested area of the responsibility for destinations and tourists, within emergency settings. It incorporates a Delphi-Scenario technique to facilitate a structured discussion of emergency management for different destination stakeholders. The Delphi exercise engaged 123 senior international stakeholders, from 9 different industry sectors, across 34 countries to provide a global perspective. The study’s principal focus is on the notion of emergency management, to identify the challenges that stakeholders would face within a disaster scenario. The exercise asked stakeholders to identify with whom the responsibility rests for 18 distinct disaster-related activities. The study proposes a responsibility allocation building-block framework which could help speed up the emergency management responses by ”knowing who is going to do what” with a particular focus on dealing with international tourists as a community in a disaster zone

What do we teach when we teach the Learning Sciences? A document analysis of 75 graduate programs

The learning sciences, as an academic community investigating human learning, emerged more than 30 years ago. Since then, graduate learning sciences programs have been established worldwide. Little is currently known, however, about their disciplinary backgrounds and the topics and research methods they address. In this document analysis of the websites of 75 international graduate learning sciences programs, we examine central concepts and research methods across institutions, compare the programs, and assess the homogeneity of different subgroups. Results reveal that the concepts addressed most frequently were real-world learning in formal and informal contexts, designing learning environments, cognition and metacognition, and using technology to support learning. Among research methods, design-based research (DBR), discourse and dialog analyses, and basic statistics stand out. Results show substantial differences between programs, yet programs focusing on DBR show the greatest similarity regarding the other concepts and methods they teach. Interpreting the similarity of the graduate programs using a community of practice perspective, there is a set of relatively coherent programs at the core of the learning sciences, pointing to the emergence of a discipline, and a variety of multidisciplinary and more heterogeneous programs “orbiting” the core in the periphery, shaping and innovating the field

Protein misfolding is the molecular mechanism underlying MCADD identified in newborn screening

Newborn screening (NBS) for medium-chain acyl-CoA dehydrogenase deficiency (MCADD) revealed a higher birth prevalence and genotypic variability than previously estimated, including numerous novel missense mutations in the ACADM gene. On average, these mutations are associated with milder biochemical phenotypes raising the question about their pathogenic relevance. In this study, we analyzed the impact of 10 ACADM mutations identified in NBS (A27V, Y42H, Y133H, R181C, R223G, D241G, K304E, R309K, I331T and R388S) on conformation, stability and enzyme kinetics of the corresponding proteins. Partial to total rescue of aggregation by co-overexpression of GroESL indicated protein misfolding. This was confirmed by accelerated thermal unfolding in all variants, as well as decreased proteolytic stability and accelerated thermal inactivation in most variants. Catalytic function varied from high residual activity to markedly decreased activity or substrate affinity. Mutations mapping to the β-domain of the protein predisposed to severe destabilization. In silico structural analyses of the affected amino acid residues revealed involvement in functionally relevant networks. Taken together, our results substantiate the hypothesis of protein misfolding with loss-of-function being the common molecular basis in MCADD. Moreover, considerable structural alterations in all analyzed variants do not support the view that novel mutations found in NBS bear a lower risk of metabolic decompensation than that associated with mutations detected in clinically ascertained patients. Finally, the detailed insight into how ACADM missense mutations induce loss of MCAD function may provide guidance for risk assessment and counseling of patients, and in future may assist delineation of novel pharmacological strategies

MR fluoroscopy in vascular and cardiac interventions (review)

Vascular and cardiac disease remains a leading cause of morbidity and mortality in developed and emerging countries. Vascular and cardiac interventions require extensive fluoroscopic guidance to navigate endovascular catheters. X-ray fluoroscopy is considered the current modality for real time imaging. It provides excellent spatial and temporal resolution, but is limited by exposure of patients and staff to ionizing radiation, poor soft tissue characterization and lack of quantitative physiologic information. MR fluoroscopy has been introduced with substantial progress during the last decade. Clinical and experimental studies performed under MR fluoroscopy have indicated the suitability of this modality for: delivery of ASD closure, aortic valves, and endovascular stents (aortic, carotid, iliac, renal arteries, inferior vena cava). It aids in performing ablation, creation of hepatic shunts and local delivery of therapies. Development of more MR compatible equipment and devices will widen the applications of MR-guided procedures. At post-intervention, MR imaging aids in assessing the efficacy of therapies, success of interventions. It also provides information on vascular flow and cardiac morphology, function, perfusion and viability. MR fluoroscopy has the potential to form the basis for minimally invasive image–guided surgeries that offer improved patient management and cost effectiveness