Identification of elderly fallers by muscle strength measures

For efficient prevention of falls among older adults, individuals at a high risk of falling need to be identified. In this study, we searched for muscle strength measures that best identified those individuals who would fall after a gait perturbation and those who recovered their balance. Seventeen healthy older adults performed a range of muscle strength tests. We measured maximum and rate of development of ankle plantar flexion moment, knee extension moment and whole leg push-off force, as well as maximum jump height and hand grip strength. Subsequently, their capacity to regain balance after tripping over an obstacle was determined experimentally. Seven of the participants were classified as fallers based on the tripping outcome. Maximum isometric push-off force in a leg press apparatus was the best measure to identify the fallers, as cross-validation of a discriminant model with this variable resulted in the best classification (86% sensitivity and 90% specificity). Jump height and hand grip strength were strongly correlated to leg press force (r = 0.82 and 0.59, respectively) and can also be used to identify fallers, although with slightly lower specificity. These results indicate that whole leg extension strength is associated with the ability to prevent a fall after a gait perturbation and might be used to identify the elderly at risk of falling

Cardiac Sympathetic Denervation Assessed With 123-Iodine Metaiodobenzylguanidine Imaging Predicts Ventricular Arrhythmias in Implantable Cardioverter-Defibrillator Patients

Objectives The purpose of this study was to evaluate whether 123-iodine metaiodobenzylguanidine (123-I MIBG) imaging predicts ventricular arrhythmias causing appropriate implantable cardioverter-defibrillator (ICD) therapy (primary end point) and the composite of appropriate ICD therapy or cardiac death (secondary end point). Background Although cardiac sympathetic denervation is associated with ventricular arrhythmias, limited data are available on the predictive value of sympathetic nerve imaging with 123-I MIBG on the occurrence of arrhythmias. Methods Before ICD implantation, patients underwent 123-I MIBG and myocardial perfusion imaging. Early and late 123-I MIBG (planar and single-photon emission computed tomography [SPECT]) imaging was performed to assess cardiac innervation (heart-to-mediastinum ratio, cardiac washout rate, and 123-I MIBG SPECT defect score). Stress-rest myocardial perfusion imaging was performed to assess myocardial infarction and perfusion abnormalities (perfusion defect scores). During follow-up, appropriate ICD therapy and cardiac death were documented. Results One-hundred sixteen heart failure patients referred for ICD therapy were enrolled. During a mean follow-up of 23 +/- 15 months, appropriate ICD therapy (primary end point) was documented in 24 (21%) patients and appropriate ICD therapy or cardiac death (secondary end point) in 32 (28%) patients. Late 123-I MIBG SPECT defect score was an independent predictor for both end points. Patients with a large late 123-I MIBG SPECT defect (summed score >26) showed significantly more appropriate ICD therapy (52% vs. 5%, p < 0.01) and appropriate ICD therapy or cardiac death (57% vs. 10%, p < 0.01) than patients with a small defect (summed score <= 26) at 3-year follow-up. Conclusions Cardiac sympathetic denervation predicts ventricular arrhythmias causing appropriate ICD therapy as well as the composite of appropriate ICD therapy or cardiac death. (J Am Coll Cardiol 2010; 55: 2769-77) (C) 2010 by the American College of Cardiology FoundationCardiovascular Aspects of Radiolog

A highly virulent variant of HIV-1 circulating in the Netherlands

We discovered a highly virulent variant of subtype-B HIV-1 in the Netherlands. One hundred nine individuals with this variant had a 0.54 to 0.74 log10 increase (i.e., a ~3.5-fold to 5.5-fold increase) in viral load compared with, and exhibited CD4 cell decline twice as fast as, 6604 individuals with other subtype-B strains. Without treatment, advanced HIV-CD4 cell counts below 350 cells per cubic millimeter, with long-term clinical consequences-is expected to be reached, on average, 9 months after diagnosis for individuals in their thirties with this variant. Age, sex, suspected mode of transmission, and place of birth for the aforementioned 109 individuals were typical for HIV-positive people in the Netherlands, which suggests that the increased virulence is attributable to the viral strain. Genetic sequence analysis suggests that this variant arose in the 1990s from de novo mutation, not recombination, with increased transmissibility and an unfamiliar molecular mechanism of virulence