Encroaching forests decouple alpine butterfly population dynamics

Over the past 50 years, the rising tree line along Jumpingpound Ridge in the Rocky Mountains of Alberta, Canada, has reduced the area of alpine meadows and isolated populations that reside within them. By analyzing an 11-year data set of butterfly population sizes for 17 subpopulations along the ridge, we show that forest habitat separating alpine meadows decouples the dynamics of populations of the alpine butterfly Parnassius smintheus. Although the distance between populations is often negatively correlated with synchrony of dynamics, here we show that distance through forest, not Euclidean distance, determines the degree of synchrony. This effect is consistent with previous results demonstrating that encroaching forest reduces dispersal among populations and reduces gene flow. Decoupling dynamics produces more smaller independent populations, each with greater risk of local extinction, but decoupling may produce a lower risk of regional extinction in this capricious environment.     

Diabetes insipidus: diagnosis and treatment of a complex disease

Diabetes insipidus, characterized by excretion of copious volumes of dilute urine, can be life-threatening if not properly diagnosed and managed. It can be caused by two fundamentally different defects: inadequate or impaired secretion of antidiuretic hormone (ADH) from the posterior pituitary gland (neurogenic or central diabetes insipidus) or impaired or insufficient renal response to ADH (nephrogenic diabetes insipidus). The distinction is essential for effective treatment.     

Sudden cardiac death associated with an extremely rare coronary anomaly of the left and right coronary arteries arising exclusively from the posterior (noncoronary) sinus of valsalva

Congenital anomalies of the coronary arteries are relatively uncommon conditions and have been associated with sudden cardiac death (SCD) in children. Although anomalous coronary artery distribution is widely reported in the literature, no articles to date address the origin of both the right (RCA) and left coronary arteries (LCA) from the posterior (noncoronary) sinus of Valsalva. This is a report of a 16-year-old black male in good health, who collapsed and was unable to be resuscitated after physical exertion while playing basketball. In this patient, postmortem evaluation revealed the LCA and RCA originating exclusively from the posterior (noncoronary) sinus with acute angle takeoff of the LCA which likely lead to ischemia, causing SCD. We discuss the incidence of coronary artery anomalies and the proposed mechanisms that led to SCD in these patients.     

Treatment of hypertension in metabolic syndrome: Implications of recent clinical trials

Metabolic syndrome represents a constellation of hypertension, abdominal obesity, impaired fasting glucose, and dyslipidemia, and it has been shown to be a risk factor for cardiovascular disease. The components of metabolic syndrome are rapidly emerging as epidemics of the twenty-first century, and reduction of these underlying causes, such as obesity, physical inactivity, and atherogenic diet, is first-line therapy. Treatment of hypertension and other cardiometabolic risk factors of the syndrome is also required. Evidence demonstrates a relationship between hypertension, type 2 diabetes mellitus, and several vascular and metabolic abnormalities that are components of metabolic syndrome. Hypertension associated with metabolic syndrome has pathophysiologic characteristics that provide clinical challenges as well as opportunities for successful therapeutic interventions. This article reviews the treatment of hypertension as a metabolic and vascular disease and also opens a new paradigm for the treatment of metabolic syndrome, which affects nearly one quarter of the world’s population.     

The wealth of nations and the dissemination of cardiovascular research

Background

This study aimed at understanding whether investigators from less wealthy countries were at a disadvantage in disseminating their research, after accounting for potential differences in research quality and infrastructure.

Methods and Results

In this bibliometric analysis a representative random selection of 10% (n = 1002 studies) of all abstracts submitted to the European Society of Cardiology (ESC) congress 2006 was followed for publication and citation from September 2006 to December 2011. The main variable of interest was the per-capita gross domestic product (GDP) of the country of the principal investigator. Using multivariable models that adjusted for socioeconomic indicators and previously identified markers of research quality, we examined the relationship between per-capita GDP and three study endpoints: Acceptance at the ESC congress, full-text publication, and number of two-year citations. Among 1002 abstracts from 63 countries, per-capita GDP was positively correlated with all three study endpoints. After adjusting for markers of research quality and infrastructure, per-capita GDP remained a strong predictor for acceptance at the ESC congress (adjusted OR for every 10,000 USD increase in per-capita GDP, 1.44; 95% CI, 1.15 to 1.80), full-text publication within 5 years (adjusted OR, 1.49; 95% CI, 1.17 to 1.90), and high citation frequency (adjusted OR, 2.30; 95% CI, 1.31 to 4.04). These findings were largely consistent in a subgroup of abstracts of high-quality, prospective clinical trials.

Conclusion

Investigators in less wealthy countries face challenges to disseminate their research, even after accounting for potential differences in the quality of their work and research infrastructure.     

Predictors and Causes of Long-Term Mortality in Elderly Patients with Acute Venous Thromboembolism: A Prospective Cohort Study

Background

Long-term predictors and causes of death are understudied in elderly patients with acute venous thromboembolism.