Radionuclide left ventricular angiography during exercise in ischemic heart disease.

Radionuclide angiocardiography during exercise is one of the latest advances in nuclear cardiology and is being introduced into clinical practice. In this article the pathophysiological principles of this technique and the method with which it is used to evaluate patients with ischemic heart diseases are outlined, the various patterns of response in these patients are illustrated, and factors that limit the interpretation of the results, including the level of exercise achieved, are discussed.     

Left ventricular function during graded exercise in patients with coronary artery disease and in control subjects.

The left ventricular function of 30 patients with coronary artery disease and 11 control subjects was studied by electrocardiography gated cardiac blood pool scintigraphy as the participants lay on their backs and either rested or exercised on a cycle ergometer at graded levels on intensity. The control subject showed a progressive increase in ejection fraction from rest (51% +/- 7%) to intermediate (56% +/- 10%, P less than 0.05) and maximum levels of exercise (64% +/- 10%, P less than 0.001). All the patients showed a decrease in ejection fraction from rest (42% +/- 16%) to their maximal level of exercise (36% +/- 11%, P less than 0.001). However, the response of some of the patients to intermediate exercise ranged from a decrease or no change to an increase in ejection fraction. Thus, exercise at maximal intensity is necessary to induce the left ventricular dysfunction that is diagnostic of coronary artery disease.     

Synthesis, computer modeling and biological evaluation of novel protein kinase C agonists based on a 7-membered lactam moiety

4-Hydroxymethyl-5a-methyl-1,3,4,5,5a beta,6,7,8,9,9a alpha-decahydro-2H-benz[d]azepin-2-ones (4-12), which were designed to mimic the biologically active conformation of teleocidins and benzolactams, were synthesized and evaluated for the ability to compete with [3H]phorbol 12,13-dibutyrate in a PKC delta binding assay. Among the compounds, 10-12 showed potent binding affinity, with inhibition constants (Ki) of low nanomolar order. Computational docking simulation also indicates that the relative positions of the hydrogen-bonding sites and hydrophobic regions of the compounds are well matched to the PKC delta binding site.     

The More the Better? A Comparison of the Information Sources Used by the Public during Two Infectious Disease Outbreaks

Recent infectious disease outbreaks have resulted in renewed recognition of the importance of risk communication planning and execution to public health control strategies. Key to these efforts is public access to information that is understandable, reliable and meets their needs for informed decision-making on protective health behaviours. Learning from the trends in sources used in previous outbreaks will enable improvements in information access in future outbreaks. Two separate random-digit dialled telephone surveys were conducted in Alberta, Canada, to explore information sources used by the public, together with their perceived usefulness and credibility, during the 2003 Severe Acute Respiratory Syndrome (SARS) epidemic (n = 1209) and 2009–2010 H1N1 pandemic (n = 1206). Traditional mass media were the most used information sources in both surveys. Although use of the Internet increased from 25% during SARS to 56% during H1N1, overall use of social media was not as high as anticipated. Friends and relatives were commonly used as an information source, but were not deemed very useful or credible. Conversely, doctors and health professionals were considered credible, but not consulted as frequently. The use of five or more information sources increased by almost 60% between the SARS and H1N1 surveys. There was a shift to older, more educated and more affluent respondents between the surveys, most likely caused by a decrease in the use of landlines amongst younger Canadians. It was concluded that people are increasingly using multiple sources of health risk information, presumably in a complementary manner. Subsequently, although using online media is important, this should be used to augment rather than replace more traditional information channels. Efforts should be made to improve knowledge transfer to health care professionals and doctors and provide them with opportunities to be more accessible as information sources. Finally, the future use of telephone surveys needs to account for the changing demographics of the respondents accessed through such surveys.     

From Cradle to Grave: Extended Producer Responsibility for Household Hazardous Wastes in British Columbia

Household hazardous wastes (HHWs), the discarded pesticides, solvents, paints, lubricating oil, and similar products common to residences throughout the industrial world, create problems for governments charged with managing solid waste. When disposed of improperly in landfills or incinerators or if dumped illegally, HHW may contribute to soil and water contamination. A most common management tool for HHW is a special collection effort that segregates HHW from normal trash and disposes of it in an approved manner, all at a higher cost to the governmental jurisdiction. The Canadian province of British Columbia (BC) has undertaken a different approach, based on the use of extended producer responsibility (EPR). BC's efforts began in 1992 with adoption of a regulation on used lubricating oil (lube oil). More than 40 million liters (L) of used lube oil have been collected annually through the EPR system established under this regulation. A regulation establishing producer responsibility for postconsumer paints followed in 1994. BC enacted an additional regulation establishing EPR in 1997 for solvents/flammable liquids, domestic pesticides, gasoline, and pharmaceuticals. As a result of the application of EPR to HHW, local government costs for managing HHW and the amount of HHW identified in municipal waste have declined. Although the regulations appear to have mixed success in prompting consumers to avoid products that result in HHW, there are indications that they may be more effective than conventional management efforts. Based on BC's experience with EPR, key factors for successful implementation include maintaining flexibility in program design, creating viable funding alternatives, aggressive enforcement to provide a level playing field, and adopting policies that maximize diversion of HHW from landfills, while minimizing waste generation, setting targets for reuse and recycling, promoting consumer awareness and convenience, involving local government jurisdictions, and monitoring outcomes.     

Familial ADH-responsive diabetes insipidus: response to thiazides and chlorpropamide

Twenty cases of familial ADH-responsive diabetes insipidus were identified within five generations, and eight patients were studied by one of two established dehydration protocols. In each case there was partial to total failure of response to the initial administration of ADH which was slowly corrected by continued administration. This initial failure can lead to misinterpretation of the dehydration test unless the medullary solute washout effect is taken into account in chronically polyuric patients.Treatment consisted of thiazides and/or chlorpropamide. All cases responded well.The response to chlorpropamide suggests that the failure of ADH production is not complete in these patients, and that the major defect is a failure of ADH release in response to normal stimuli. Chlorpropamide may act by either facilitating ADH release or by synergistically interacting with available ADH at the tubular level.     

Lung and leg scanning with 99mTc-labelled albumin macroaggregates

The routine injection of ^99mTc-macroaggregated albumin into dorsal foot veins for lung scanning allows en passant assessment to be made regarding the presence of deep venous phlebitis. The radiopharmaceutical adhered to fibrin deposits in veins of calves and thighs in 103 of 386 examinations. In the 103 patients with a presumptive diagnosis of thrombophlebitis, microembolization from labelled thrombi, producing “hot spots” in the lungs, occurred in 25 cases. It is inferred that pulmonary microembolization is a very common event in patients with phlebitis.