Impey S.G.,Liverpool John Moores University |
Smith D.,Liverpool John Moores University |
Robinson A.L.,Liverpool John Moores University |
Owens D.J.,Liverpool John Moores University |
And 7 more authors.
Amino Acids | Year: 2015
Given that the enhanced oxidative adaptations observed when training in carbohydrate (CHO)-restricted states is potentially regulated through free fatty acid (FFA)-mediated signalling and that leucine-rich protein elevates muscle protein synthesis, the present study aimed to test the hypothesis that leucine-enriched protein feeding enhances circulating leucine concentration but does not impair FFA availability or whole body lipid oxidation during exercise. Nine males cycled for 2 h at 70 % VO2peak when fasted (PLACEBO) or having consumed a whey protein solution (WHEY) or a leucine-enriched whey protein gel (GEL), administered as 22 g 1 h pre-exercise, 11 g/h during and 22 g 30 min post-exercise. Total leucine administration was 14.4 g and 6.3 in GEL and WHEY, respectively. Mean plasma leucine concentrations were elevated in GEL (P = 0.001) compared with WHEY and PLACEBO (375 ± 100, 272 ± 51, 146 ± 14 μmol L-1, respectively). No differences (P = 0.153) in plasma FFA (WHEY 0.53 ± 0.30, GEL 0.45 ± 0.25, PLACEBO 0.65 ± 0.30, mmol L-1) or whole body lipid oxidation during exercise (WHEY 0.37 ± 0.26, GEL 0.36 ± 0.24, PLACEBO 0.34 ± 0.24 g/min) were apparent between trials, despite elevated (P = 0.001) insulin in WHEY and GEL compared with PLACEBO (38 ± 16, 35 ± 16, 22 ± 11 pmol L-1, respectively). We conclude that leucine-enriched protein feeding does not impair FFA availability or whole body lipid oxidation during exercise, thus having practical applications for athletes who deliberately train in CHO-restricted states to promote skeletal muscle adaptations. © 2014 Springer-Verlag Wien.
Wilkinson D.J.,University of Nottingham |
Wilkinson D.J.,Royal Derby Hospital Center |
Franchi M.V.,University of Nottingham |
Franchi M.V.,Royal Derby Hospital Center |
And 16 more authors.
American Journal of Physiology - Endocrinology and Metabolism | Year: 2014
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. © 2014 the American Physiological Society.
PubMed | Royal Derby Hospital Center and University of Nottingham
Type: | Journal: Breast (Edinburgh, Scotland) | Year: 2016
The aim of our study was to assess various predictors for local recurrence (LR) in patients undergoing breast conservation surgery (BCS) for ductal carcinoma in situ (DCIS).An audit was performed of 582 consecutive patients with DCIS between Jan 1975 to June 2008. In patients undergoing BCS, local guidelines reported a margin of 10mm during the above period. Guideline with regard to margin of excision changes soon after this period. We retrospectively analysed clinical and pathological risk factors for local recurrence in patients undergoing BCS. Statistical analysis was carried out using SPSS version 19, and a cox regression model for multivariate analysis of local recurrence was used.Overall 239 women had BCS for DCIS during the above period. The actuarial 5-year recurrence rate was 9.6%. The overall LR rate was 17% (40/239. LR was more common in patients 50 years: (10/31 patients, 32%) compared to patients>50 years (30/208, 14%, P=0.02). Forty three per cent of patients (6/14) with <5mm margin developed LR which was significantly higher compared to patients with 5-9mm margin (12%, 3/25) and with 10mm margin (14%, 27/188, P=0.01). On multivariate analysis age 50 years, <5mm pathological margin were independent prognostic factors for local recurrence.Our study shows that younger age (50 years) and a margin < 5mm are poor prognostic factors for LR in patients undergoing breast conservation surgery for DCIS.