Changes in the Left Atrial-Esophageal Relationship with the Insertion of An Esophageal Protective Device: A Cadaveric Imaging Study

Background: Atrial fibrillation is the most common cardiac rhythm disorder in North America and is frequently treated by a minimally invasive procedure called catheter ablation. A rare, but often fatal complication of this procedure is development of an atrial-esophageal fistula (AEF) due to the proximity of the esophagus to the left atrium (LA) of the heart. Esophageal protective devices may potentially mitigate the risk of developing an AEF but their impact on the relationship between the esophagus and LA is unknown. This study will investigate the relevant anatomical changes that occur upon insertion of an esophageal protective device. Methods: 13 fresh cadaveric torsos were scanned with and without an esophageal protective device on the computed tomography (CT) modality. The width and anterior-posterior dimension of the esophagus were measured digitally and compared between pre- and post-device insertion scans. From the scans, 3D models of the LA and esophagus were created and used for a spatial analysis of their relationship. A heatmap was generated for each LA highlighting areas of close contact with the esophagus and how they changed post-device insertion. Results: Preliminary results have indicated the width and anterior-posterior dimension of the esophagus increase significantly with the insertion of the protective device (p \u3c 0.05). Further analysis of the esophagus-left atrial distance is still ongoing. Discussion: Data from this study will provide valuable insight on changes that could be made to the device design and potentially boost its clinical efficacy and prevent AEF formation

Conference Highlights of the 16th International Conference on Human Retrovirology: HTLV and Related Retroviruses, 26–30 June 2013, Montreal, Canada

The 16th International Conference on Human Retrovirology: HTLV and Related Retroviruses was held in Montreal, Québec from June 26 to June 30, 2013 and was therefore hosted by a Canadian city for the first time. The major topic of the meeting was human T-lymphotropic viruses (HTLVs) and was covered through distinct oral and poster presentation sessions: clinical research, animal models, immunology, molecular and cellular biology, human endogenous and emerging exogenous retroviruses and virology. In this review, highlights of the meeting are provided by different experts for each of these research areas

What makes primary care effective for people in poverty living with multiple chronic conditions?: study protocol

Abstract Background: The inverse care law persists: people living in poverty have the greatest needs and face considerable challenges in getting the care they need. Evidence reveals that GPs encounter difficulties in delivering care to poor patients, while many of those patients feel stigmatized by healthcare professionals. Patients living in poverty report negative healthcare experiences and unmet healthcare needs. Indeed, there is a growing recognition in primary care research of the importance of addressing the capabilities and social conditions of the poor when delivering care. Few studies have looked at the factors contributing to effective and "socially responsive" care for people living in poverty. Methods/Design: Our study adopts a qualitative ethnographic approach in four healthcare organizations in deprived areas of metropolitan Montreal (Québec, Canada), using patient shadowing techniques and interviews. Data will be collected through fieldwork observations and informal interviews with patients before and after consultations. We will observe medical consultations, care organization activities, and waiting areas and reception of patients. We will conduct a total of 36 individual interviews with 12 GPs and 24 patients. The interviews will be audio-recorded and transcribed for purposes of analysis. The analysis consists of debriefing sessions, coding and interpretive analysis. Discussion: This study aims to investigate how positive healthcare interactions between physicians and patients can improve the management of chronic conditions. We hypothesize that factors related to care organization, to healthcare professionals' experience and to patients may enhance the quality of healthcare interactions, which may have positive impacts for preventing and managing chronic conditions. Our study will provide a unique set of data grounded in the perspectives of healthcare professionals and of patients living in poverty

Risk assessment for the spread of Serratia marcescens within dental-unit waterline systems using Vermamoeba vermiformis

Vermamoeba vermiformis is associated with the biofilm ecology of dental-unit waterlines (DUWLs). This study investigated whether V. vermiformis is able to act as a vector for potentially pathogenic bacteria and so aid their dispersal within DUWL systems. Clinical dental water was initially examined for Legionella species by inoculating it onto Legionella selective-medium plates. The molecular identity/profile of the glassy colonies obtained indicated none of these isolates were Legionella species. During this work bacterial colonies were identified as a non-pigmented Serratia marcescens. As the water was from a clinical DUWL which had been treated with Alpron™ this prompted the question as to whether S. marcescens had developed resistance to the biocide. Exposure to Alpron™ indicated that this dental biocide was effective, under laboratory conditions, against S. marcescens at up to 1x108 colony forming units/millilitre (cfu/ml). V. vermiformis was cultured for eight weeks on cells of S. marcescens and Escherichia coli. Subsequent electron microscopy showed that V. vermiformis grew equally well on S. marcescens and E. coli (p = 0.0001). Failure to detect the presence of S. marcescens within the encysted amoebae suggests that V. vermiformis is unlikely to act as a vector supporting the growth of this newly isolated, nosocomial bacterium

Determining the Drift Time of Charge Carriers in P-Type Point-Contact HPGe Detectors

An algorithm to measure the drift time of charge carriers in p-type point contact (PPC) high-purity germanium (HPGe) detectors from the signals processed with a charge-sensitive preamplifier is introduced. It is demonstrated that the drift times can be used to estimate the distance of charge depositions from the point contact and to characterize losses due to charge trapping. A correction for charge trapping effects over a wide range of energies is implemented using the measured drift times and is shown to improve the energy resolution by up to 30%.Comment: 16 pages, 8 figures, submitted to Nucl. Instrum. Meth.

Genetic diversity of collaborative cross mice enables identification of novel rift valley fever virus encephalitis model

Rift Valley fever (RVF) is an arboviral disease of humans and livestock responsible for severe economic and human health impacts. In humans, RVF spans a variety of clinical manifestations, ranging from an acute flu-like illness to severe forms of disease, including late-onset encephalitis. The large variations in human RVF disease are inadequately represented by current murine models, which overwhelmingly die of early-onset hepatitis. Existing mouse models of RVF encephalitis are either immunosuppressed, display an inconsistent phenotype, or develop encephalitis only when challenged via intranasal or aerosol exposure. In this study, the genetically defined recombinant inbred mouse resource known as the Collaborative Cross (CC) was used to identify mice with additional RVF disease phenotypes when challenged via a peripheral foot-pad route to mimic mosquito-bite exposure. Wild-type Rift Valley fever virus (RVFV) challenge of 20 CC strains revealed three distinct disease phenotypes: early-onset hepatitis, mixed phenotype, and late-onset encephalitis. Strain CC057/Unc, with the most divergent phenotype, which died of late-onset encephalitis at a median of 11 days post-infection, is the first mouse strain to develop consistent encephalitis following peripheral challenge. CC057/Unc mice were directly compared to C57BL/6 mice, which uniformly succumb to hepatitis within 2–4 days of infection. Encephalitic disease in CC057/Unc mice was characterized by high viral RNA loads in brain tissue, accompanied by clearance of viral RNA from the periphery, low ALT levels, lymphopenia, and neutrophilia. In contrast, C57BL/6 mice succumbed from hepatitis at 3 days post-infection with high viral RNA loads in the liver, viremia, high ALT levels, lymphopenia, and thrombocytopenia. The identification of a strain of CC mice as an RVFV encephalitis model will allow for future investigation into the pathogenesis and treatment of RVF encephalitic disease and indicates that genetic background makes a major contribution to RVF disease variation

Astroparticle Physics with a Customized Low-Background Broad Energy Germanium Detector

The MAJORANA Collaboration is building the MAJORANA DEMONSTRATOR, a 60 kg array of high purity germanium detectors housed in an ultra-low background shield at the Sanford Underground Laboratory in Lead, SD. The MAJORANA DEMONSTRATOR will search for neutrinoless double-beta decay of 76Ge while demonstrating the feasibility of a tonne-scale experiment. It may also carry out a dark matter search in the 1-10 GeV/c^2 mass range. We have found that customized Broad Energy Germanium (BEGe) detectors produced by Canberra have several desirable features for a neutrinoless double-beta decay experiment, including low electronic noise, excellent pulse shape analysis capabilities, and simple fabrication. We have deployed a customized BEGe, the MAJORANA Low-Background BEGe at Kimballton (MALBEK), in a low-background cryostat and shield at the Kimballton Underground Research Facility in Virginia. This paper will focus on the detector characteristics and measurements that can be performed with such a radiation detector in a low-background environment.Comment: Submitted to NIMA Proceedings, SORMA XII. 9 pages, 4 figure

Shelf-derived iron inputs drive biological productivity in the southern Drake Passage

Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 23 (2009): GB4014, doi:10.1029/2008GB003406.In the Southern Ocean near the Antarctic Peninsula, Antarctic Circumpolar Current (ACC) fronts interact with shelf waters facilitating lateral transport of shelf-derived components such as iron into high-nutrient offshore regions. To trace these shelf-derived components and estimate lateral mixing rates of shelf water, we used naturally occurring radium isotopes. Short-lived radium isotopes were used to quantify the rates of shelf water entrainment while Fe/228Ra ratios were used to calculate the Fe flux. In the summer of 2006 we found rapid mixing and significant lateral iron export, namely, a dissolved iron flux of 1.1 × 105 mol d−1 and total acid leachable iron flux of 1.1 × 106 mol d−1 all of which is transported in the mixed layer from the shelf region offshore. This dissolved iron flux is significant, especially considering that the bloom observed in the offshore region (0.5–2 mg chl a m−3) had an iron demand of 1.1 to 4 × 105 mol Fe. Net vertical export fluxes of particulate Fe derived from 234Th/238U disequilibrium and Fe/234Th ratios accounted for only about 25% of the dissolved iron flux. On the other hand, vertical upward mixing of iron rich deeper waters provided only 7% of the lateral dissolved iron flux. We found that similarly to other studies in iron-fertilized regions of the Southern Ocean, lateral fluxes overwhelm vertical inputs and vertical export from the water column and support significant phytoplankton blooms in the offshore regions of the Drake Passage.This work was funded by the National Science Foundation (ANT-0443869 to M.A.C.)