Association of Accelerometry-Measured Physical Activity and Cardiovascular Events in Mobility-Limited Older Adults: The LIFE (Lifestyle Interventions and Independence for Elders) Study.

BACKGROUND:Data are sparse regarding the value of physical activity (PA) surveillance among older adults-particularly among those with mobility limitations. The objective of this study was to examine longitudinal associations between objectively measured daily PA and the incidence of cardiovascular events among older adults in the LIFE (Lifestyle Interventions and Independence for Elders) study. METHODS AND RESULTS:Cardiovascular events were adjudicated based on medical records review, and cardiovascular risk factors were controlled for in the analysis. Home-based activity data were collected by hip-worn accelerometers at baseline and at 6, 12, and 24 months postrandomization to either a physical activity or health education intervention. LIFE study participants (n=1590; age 78.9±5.2 [SD] years; 67.2% women) at baseline had an 11% lower incidence of experiencing a subsequent cardiovascular event per 500 steps taken per day based on activity data (hazard ratio, 0.89; 95% confidence interval, 0.84-0.96; P=0.001). At baseline, every 30 minutes spent performing activities ≥500 counts per minute (hazard ratio, 0.75; confidence interval, 0.65-0.89 [P=0.001]) were also associated with a lower incidence of cardiovascular events. Throughout follow-up (6, 12, and 24 months), both the number of steps per day (per 500 steps; hazard ratio, 0.90, confidence interval, 0.85-0.96 [P=0.001]) and duration of activity ≥500 counts per minute (per 30 minutes; hazard ratio, 0.76; confidence interval, 0.63-0.90 [P=0.002]) were significantly associated with lower cardiovascular event rates. CONCLUSIONS:Objective measurements of physical activity via accelerometry were associated with cardiovascular events among older adults with limited mobility (summary score >10 on the Short Physical Performance Battery) both using baseline and longitudinal data. CLINICAL TRIAL REGISTRATION:URL: http://www.clinicaltrials.gov. Unique identifier: NCT01072500

Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy

In vivo expansion of the endogenous B-cell compartment stimulated by radiation and serial bone marrow transplantation induces B-cell leukaemia in mice

Chronic lymphocytic leukaemia (CLL) is a malignancy of CD5(+) B cells. This B-cell lineage is established during ontogeny and replenished by the process of self-renewal. Spontaneous and induced leukaemias that frequently affect this lineage are thought to arise as a result of the frequent cell division required to maintain the population throughout adulthood and in response to repeated exposure to environmental antigens. In a series of bone marrow transplant (BMT) experiments performed in B6D2F1 mice, B-cell leukaemia occurred in recipients of serially transplanted syngeneic bone marrow. This study was therefore designed to determine the frequency and phenotype of the observed leukaemia. Male donor cells were initially transplanted into lethally irradiated female hosts and secondary (2 degrees) BMT was performed at 3 months. At 1, 2, 3 and 16 months following primary (1 degrees) BMT, and when 2 degrees BMT recipients developed leukaemia, animals were sacrificed and their tissues extensively examined. These analyses confirmed a host-derived CD5(+) transplantable B-cell leukaemia that was initiated in 50% of 1 degrees BMT recipients. With serial passage, the leukaemia became more aggressive and lost CD5 expression, suggesting transformation to a high-grade leukaemia/lymphoma. This previously unreported observation suggests that the combination of radiation and subsequent serial transplantation induces a proliferative stress to the host B-cell compartment that is causative in leukaemic transformation