Tired of jogging to burn more calories? Try working on a crossword puzzle.

EurekAlert: A Universite Laval research team has demonstrated that intellectual work induces a substantial increase in calorie intake. The details of this discovery, which could go some way to explaining the current obesity epidemic, are published in the most recent issue of Psychosomatic Medicine.

Interferon-{gamma} Release Assays for Diagnosing Mycobacterium tuberculosis Infection in Renal Dialysis Patients

Background and objectives: End-stage renal disease (ESRD) patients are at high risk for tuberculosis (TB). IFN- release assays that assess immune responses to specific TB antigens offer potential advantages over tuberculin skin testing (TST) in screening such patients for Mycobacterium tuberculosis infection. This study sought to determine whether IFN- release assay results are more closely associated with recent TB exposure than TST results.

Design, setting, participants, and measures: Prospective cohort investigation of patients at a hemodialysis center with a smear-positive case of TB. Patients without a history of TB underwent initial and repeat testing with TST, and with the IFN- assays QuantiFERON-TB Gold® (QFT-G) and ELISPOT test. Outcome measures included the prevalence of positive test results, identification of factors associated with positive results, and test result discordance.

Results: A total of 100 (47% foreign born; median age, 55 yr; age range, 18 to 83 yr) of 124 eligible patients were enrolled. Twenty-six persons had positive TST results, 21 had positive QFT-G results, and 27 had positive ELISPOT results. Patients with TB case contact were likely to have a positive QFT-G result (P = 0.02) and ELISPOT results (P = 0.04), whereas TB case contact was not associated with positive TST results (P = 0.7). Positive TST results were associated with foreign birth (P = 0.04) and having had a TST in the previous year (P = 0.04).

Conclusions: Positive IFN- assay results were more closely associated with recent TB exposure than were positive TST results. QFT-G and ELISPOT might offer a better method for detecting TB infection in ESRD patients.

Waist:hip ratio predicts subsequent chronic kidney disease better than BMI

Waist:hip ratio predicts subsequent chronic kidney disease better than BMI

Nature Clinical Practice Nephrology 4, 464 (2008). doi:10.1038/ncpneph0897

Pulmonary Hypertension, Right Ventricular Failure, and Kidney: Different from Left Ventricular Failure?

In this article, the pathophysiology of left ventricular failure is reviewed. By contrast, the paucity of information about pulmonary arterial hypertension and right ventricular failure is acknowledged. The potential mechanisms whereby renal sodium and water retention in right ventricular failure secondary to pulmonary arterial hypertension can occur, despite normal left ventricular function, are discussed. With right ventricular failure as the primary cause of death in patients with pulmonary hypertension, more information about the mechanisms of renal sodium and water retention in these patients is direly needed. Specifically, studies to examine the activation of the neurohumoral axis at various stages of pulmonary arterial hypertension and right ventricular failure, including inhibition of mineralocorticoid and V2 vasopressin receptors, are indicated.

Coronary Artery Calcification, ADMA, and Insulin Resistance in CKD Patients

Background and objectives: It is known that coronary artery calcification (CAC) develops in chronic kidney disease (CKD) before initiation of renal replacement therapy, and factors associated with CKD mineral and bone disorders (CKD-MBDs) are involved. However, little information is available about any association between plasma levels of asymmetric dimethylarginine (ADMA), insulin resistance, and CAC.

Design, setting, participants, & measurements: A total of 111 CKD patients (79 men, 32 women; glomerular filtration rate [GFR] median, 33.7 ml/min per 1.73 m²), free of cardiovascular disease, were consecutively recruited along with 30 age-matched healthy subjects. Coronary artery calcification scores (CACS) were measured by multidetector-row CT according to Agatston score.

Results: In CKD patients, CACS was distributed widely from 0 to 2901, while in age-matched, healthy control subjects (n = 30), CACS showed a range from 0 to 307. GFR had a significant negative correlation with CACS. Plasma ADMA levels were negatively correlated with GFR and positively correlated with CACS. When CACS was divided into quartiles (<50, n = 56; 50 to 300, n = 24; 300 to 600, n = 14; >600, n = 17), the patients with CACS >600 had significantly higher values of HOMA-IR, plasma ADMA levels, and fibrinogen along with serum levels of phosphorus, compared with those in patients having CACS <50. Multivariate regression analysis determined HOMA-IR as an independent contributing factor to CACS.

Conclusions: CAC becomes more prevalent and severe with a decline in GFR, and plasma ADMA levels and insulin resistance, independent of factors associated with CKD-MBD, are correlated with CAC.