A validation of the application of D2O stable isotope tracer techniques for monitoring day-to-day changes in muscle protein subfraction synthesis in humans

Quantification of muscle protein synthesis (MPS) remains a cornerstone for understanding the control of muscle mass. Traditional [13C]amino acid tracer methodologies necessitate sustained bed rest and intravenous cannulation(s), restricting studies to ∼12 h, and thus cannot holistically inform on diurnal MPS. This limits insight into the regulation of habitual muscle metabolism in health, aging, and disease while querying the utility of tracer techniques to predict the long-term efficacy of anabolic/anticatabolic interventions. We tested the efficacy of the D2O tracer for quantifying MPS over a period not feasible with 13C tracers and too short to quantify changes in mass. Eight men (22 ± 3.5 yr) undertook one-legged resistance exercise over an 8-day period (4 × 8–10 repetitions, 80% 1RM every 2nd day, to yield “nonexercised” vs. “exercise” leg comparisons), with vastus lateralis biopsies taken bilaterally at 0, 2, 4, and 8 days. After day 0 biopsies, participants consumed a D2O bolus (150 ml, 70 atom%); saliva was collected daily. Fractional synthetic rates (FSRs) of myofibrillar (MyoPS), sarcoplasmic (SPS), and collagen (CPS) protein fractions were measured by GC-pyrolysis-IRMS and TC/EA-IRMS. Body water initially enriched at 0.16–0.24 APE decayed at ∼0.009%/day. In the nonexercised leg, MyoPS was 1.45 ± 0.10, 1.47 ± 0.06, and 1.35 ± 0.07%/day at 0–2, 0–4, and 0–8 days, respectively (∼0.05–0.06%/h). MyoPS was greater in the exercised leg (0–2 days: 1.97 ± 0.13%/day; 0–4 days: 1.96 ± 0.15%/day, P < 0.01; 0–8 days: 1.79 ± 0.12%/day, P < 0.05). CPS was slower than MyoPS but followed a similar pattern, with the exercised leg tending to yield greater FSRs (0–2 days: 1.14 ± 0.13 vs. 1.45 ± 0.15%/day; 0–4 days: 1.13 ± 0.07%/day vs. 1.47 ± 0.18%/day; 0–8 days: 1.03 ± 0.09%/day vs. 1.40 ± 0.11%/day). SPS remained unchanged. Therefore, D2O has unrivaled utility to quantify day-to-day MPS in humans and inform on short-term changes in anabolism and presumably catabolism alike

The Year of the Audit Committee

Offers a look at the efforts of the United States Securities and Exchange Commission to reshape and reform auditing and improve corporate governance and accountability. Impact of the efforts on the internal audit process; Creation of the Blue Ribbon Commission on Audit Committees by the National Association of Corporate Directors; Audit committee\u27s responsibilities and practices

Social policy and professional self-interest: Physician responses to DRGS

Prospective hospital reimbursement based on Diagnosis Related Groups (DRGs) began in 1983 for Medicare patients, and many states are adopting similar systems for Medicaid recipients in an attempt to curb rising health care costs. Because of their unprecedented intrusiveness compared to previous cost-containment measures and because they explicitly introduce financial incentives to reduce services, DRGs have great potential to affect health care delivery. To determine the effects of DRGs on hospitals and physicians, six months of ethnographic fieldwork was carried out on the medicine and pediatrics services of a university-affiliated hospital during the first year of DRG-based reimbursement. Observations and interviews were used to discern institutional responses to DRGs and physician knowledge of, experience with, and reactions to this cost-containment effort. Our findings indicate that the hospital instituted many changes to protect its interests. Data gathered from patients' abstracts suggest providers are successfully dealing with the new system; the average length of stay for Medicare patients was reduced by 38% in the first year of prospective reimbursement, compared with a 15% reduction for other patients (PDRGs cost-containment prospective payment health care delivery