Stress testing and non-invasive coronary angiography in patients with suspected coronary artery disease: time for a new paradigm

Diagnosis and management of coronary artery disease represents major challenges to our health care system, affecting millions of patients each year. Until recently, the diagnosis of coronary artery disease was possible only through cardiac catheterization and invasive coronary angiography. To avoid the risks of an invasive procedure, stress testing is often employed for an initial assessment of patients with suspected coronary artery disease, serving as a gatekeeper for cardiac catheterization. With the emergence of non-invasive coronary angiography, the question arises if such a strategy is still sensible, particularly, in view of only a modest agreement between stress testing results and the presence of coronary artery disease established by cardiac catheterization. Much data in support of the diagnostic accuracy and prognostic value of non-invasive coronary angiography by computed tomography have emerged within the last few years. These data challenge the role of stress testing as the initial imaging modality in patients with suspected coronary artery disease. This article reviews the clinical utility, limitations, as well as the hazards of stress testing compared with non-invasive coronary artery imaging by computed tomography. Finally, the implications of this review are discussed in relation to clinical practice

Methyiphenidate vs. amphetamine: Comparative review

This article compares the two most common medications for Attention-Deficit/Hyperactivity Disorder (ADHD), using data from controlled studies. Medline and Psychinfo searches were done for 1984-1996 with the key words methylphenidate (MPH) and amphetamine (AMP); these were supplemented with known prior and recent literature. Of 92 animal studies found, 15 showed clear differences between the two drugs. Ten reports of controlled crossover ADHD clinical trials (three in the same sample) and a dozen other articles comparing the two drugs in humans were found. MPH is a pure re-uptake inhibitor of catecholamines, especially dopamine; AMP also releases catecholamines. Lab animals showed differential interactions with other drugs and with behavioral paradigms. Human response profiles are noncongruent. An ADHD patient who fails on one stimulant should try the other. Of 174 patients in the 6 clearest crossover studies, 48 responded better to AMP, 27 to MPH, and at least 72 to both, which is an 87+% overall response rate if both are tried. All crossovers, except the one with comorbid Tourette's, showed a nonsignificant tendency for AMP superiority in response rate. Summed data suggest suspected differences in side effects (AMP more sleep and appetite loss and exacerbation of tics in comorbid Tourette's, MPH possibly more depression/apathy and stomachaches) and effects on comorbid disorders (AMP better for conduct/oppositional symptoms, MPH for Tourette's and possibly learning disorder (LD). Most of the clinical differences are tendencies rather than statistically significant

Variation in Recruitment and Early Demography in Pinus Rigida Following Crown Fire in the Pine Barrens of Long Island, New York

Following severe, stand-replacing fires in 1995, we quantified emergence, growth and survival in Pinus rigida seedlings in eight stands in three areas of the pine barrens of Long Island, New York, USA, and examined factors contributing to spatial and temporal variation in recruitment. We followed 6431 marked seedlings in the first cohort following fire, as well as additional cohorts in subsequent years, for 7 years to assess the effects of fire intensity, soil characteristics, intraspecific density, interspecific competition and facilitation on variation in early demography at three different scales. We found substantial variation in many of the demographic parameters measured between plots within stands (10–50 m apart), among stands within areas (600– 1500 m apart), and among forest areas (5 –30 km apart), as well as among years. Almost all adult P. rigida in most of the stands studied were killed by the 1995 fires and population recovery therefore depended upon recruitment from seed. Initial recruitment appears to be largely determined by seed limitation, which was affected by fire intensity combined with serotiny and other factors. Subsequent seedling survival and growth were determined largely by inherent differences among areas and sites in factors including cover of the shrub Quercus ilicifolia and soil texture and composition. Initial seedling density, and subsequent survival and growth, varied among plots within sites, among sites within areas, and among areas. Early survival was negatively correlated with intraspecific seedling density, but was enhanced by neighbouring Q. ilicifolia, although these shrubs inhibited later seedling growth. Early demographic variation may determine many of the differences observed among mature populations in this landscape. Variation in demographic parameters across space and time, and over a hierarchy of scales, may have critical consequences at the population, community and landscape levels. A comprehensive evaluation of the nature and extent of such demographic variation across different systems would have major implications for understanding vegetation patterns at the population, community and landscape levels