Is T-wave alternans testing feasible in candidates for prophylactic implantable defibrillators?

AIMS: Previous studies have demonstrated that microvolt T-wave alternans (TWA) screening in patients with ischaemic and dilated cardiomyopathy is effective in identifying patients at high or low risk of sudden cardiac death. It remains unclear which percentage of potential recipients of an implantable cardioverter defibrillator (ICD) are able to perform TWA testing using an exercise protocol which is, at this moment, the golden standard. In this study, we evaluated the feasibility of TWA in the risk stratification of potential ICD recipients with ischaemic or dilated cardiomyopathy. METHODS AND RESULTS: Medical charts of 165 primary prevention ICD recipients were reviewed to decide if patients were able to perform a TWA exercise test or not. Reasons to waiver a test were: atrial fibrillation or flutter, pacemaker dependency, recent (cardiovascular) surgery (<1 month) and inability to exercise. Of the potential ICD recipients 35% had one or more of these contraindications and were therefore not suitable for testing. CONCLUSION: In several studies, TWA is a promising risk stratifier for predicting sudden cardiac death; however, in our population, 35% of the potential ICD candidates could not be tested. In order to fulfil its promise as a predictor for SCD, an alternative means to measure TWA needs to be evaluated.

The role of wildlife in transboundary animal diseases.

This paper identifies some of the more important diseases at the wildlife-livestock interface and the role wildlife plays in disease transmission. Domestic livestock, wildlife and humans share many similar pathogens. Pathogens of wild or domestic animal origin that can cause infections in humans are known as zoonotic organisms and the converse are termed as anthroponotic organisms. Seventy-seven percent of livestock pathogens and 91% of domestic carnivore pathogens are known to infect multiple hosts, including wildlife. Understanding this group of pathogens is critical to public health safety, because they infect a wide range of hosts and are most likely to emerge as novel causes of infection in humans and domestic animals. Diseases at the wildlife-livestock interface, particularly those that are zoonotic, must be an area of focus for public health programs and surveillance for emerging infectious diseases. Additionally, understanding wildlife and their role is a vital part of understanding the epidemiology and ecology of diseases. To do this, a multi-faceted approach combining capacity building and training, wildlife disease surveillance, wildlife-livestock interface and disease ecology studies, data and information sharing and outbreak investigation are needed.

Preparation and characterization of activated carbon derived from the thermo-chemical conversion of chicken manure.

Physico-chemical properties of a bioorganic char were modified by pyrolysis in the presence of NaOH, and with subsequent physical activation of carbonaceous species with CO2 a value-added activated carbon was fabricated. Bioorganic char is produced as a co-product during the production of bio-fuel from the pyrolysis of chicken litter. Untreated char contains approximately 37 wt% of C and approximately 43-45 wt% of inorganic minerals containing K, Ca, Fe, P, Cu, Mg, and Si. Carbonization and chemical activation of the char at 600 degrees C in the presence of NaOH in forming gas (4% H2 balanced with Ar) produced mainly demineralized activated carbon having BET (Brunauer, Emmett, and Teller) surface area of 486 m2/g and average pore size of 2.8 nm. Further physical activation with CO2 at 800 degrees C for 30 min resulted in activated carbon with BET surface area of 788 m2/g and average pore size of 2.2 nm. The mineral content was 10 wt%. X-ray photoelectron spectroscopy (XPS) indicated that the latter activation process reduced the pyrrolic- and/or pyridonic-N, increased pyridinic-N and formed quaternary-N at the expense of pyrrolic- and/or pyridonic-N found in the untreated char.

Developing a virtual reality-multimedia system for anatomy training.

The University of California, San Diego, School of Medicine's Learning Resources Center is developing a prototype next-generation application for anatomy education which combines virtual reality and multimedia curricular resources. The anatomy lesson utilizes polygon-based 3-D models of the hepatobiliary system created by BioGraphics Inc. of Fort Collins, Colorado which were derived from the National Library of Medicine's Visible Human Project Dataset. This article describes the needs assessment, learning objectives, and preliminary design of the current prototype. The multivariate design, the development strategy for implementing functionalities, and the engineering of critical software interface components are also outlined.

The Vesalius Project: interactive computers in anatomical instruction.

The goal of the Vesalius Project is a high-resolution, interactive 3-D atlas of human/animal anatomy, stored on a laser videodisc and displayed on graphics workstations--an an "electronic Gray's Anatomy." Students will use this computerized atlas interactively to learn the structure of the body and to understand their own bodies in health and disease. The Human Factors Research Laboratory at Colorado State University has designed and is conducting a comprehensive evaluation program for the project.

An open patch-graft technique for correction of pulmonic stenosis in the dog.

An open patch-graft technique for correction of pulmonic stenosis was performed in four dogs. A synthetic patch-graft was presutured to a partial-thickness incision in the right ventricular outflow tract and to the pulmonary artery along its cranial border. The pulmonary artery and right ventricle were incised during venous inflow occlusion, and dysplastic pulmonic valve leaflets were excised. The arteriotomy was closed by suturing the caudal margin of the incision to the patch-graft. The entire procedure was performed during mild hypothermia (30 degrees - 32 degrees C). The mean circulatory arrest time was 5.5 +/- 0.2 minutes. The mean systolic pressure gradient across the pulmonic valve before surgery was 121 +/- 29 mm Hg; after surgery it was 9 +/- 2 mm Hg.

Use of oxygen for optimizing decompression.

For over 70 years, decompression has been facilitated by the use of elevated oxygen partial pressures. Oxygen has been administered even though little is known about the proper dosage or the way in which this benefit is derived. The historical literature indicates that there is an envelope or narrow range of oxygen partial pressures that can be used. If the oxygen is too low, the incidence of decompression sickness increases; if the oxygen is too high, oxygen poisoning becomes a problem. The present study was designed to explore this oxygen envelope and to define the relationships between oxygen partial pressure, exposure time, and pressure, and to delineate their effects on pressure-reduction limits. To define the ED50 (the effective dose that produced signs of decompression sickness in 50% of the animals), we exposed 820 female albino rats to 42 experimental conditions. Results suggest that the optimum oxygen level and the size of the oxygen envelope both depend on the ambient hydrostatic pressure and the exposure time. For short "shallow" exposures, the optimum oxygen level is high and the oxygen envelope is large; for long "deep" exposures, the optimum oxygen level is reduced and the envelope is restricted.