We determined whether essential amino acid and carbohydrate supplementation could offset the catabolic response to prolonged inactivity. Major outcome measures included mixed muscle fractional synthetic rate (FSR), phenylalanine net balance, lean leg mass, and leg extension strength. On d 1 and 28, vastus lateralis muscle biopsies and femoral arteriovenous blood samples were obtained during a primed constant infusion of L-[ring-2 H 5 ]phenylalanine. Net balance and FSR were calculated over 16 h, during which the control group (CON) received a nutritionally mixed meal every 5 h (0830, 1330, and 1830 h). The experimental group (EXP) also consumed 16.5 g essential amino acids and 30 g carbohydrate (1100, 1600, and 2100 h). The dietary regimen was maintained during bedrest. FSR was higher in the EXP group on d 1 (EXP, 0.099 ؎ 0.008%/h; CON: 0.075 ؎ 0.005%/h) and d 28 (EXP, 0.093 ؎ 0.006%/h; CON, 0.055 ؎ 0.007%/h). Lean leg mass was maintained throughout bedrest in the EXP group (؉0.2 ؎ 0.3 kg), but fell in the CON group (؊0.4 ؎ 0.1 kg). Strength loss was more pronounced in the CON group (EXP, ؊8.8 ؎ 1.4 kg; CON, ؊17.8 ؎ 4.4 kg). Essential amino acid and carbohydrate supplementation may represent a viable intervention for individuals at risk of sarcopenia due to immobility or prolonged bedrest. (J Clin Endocrinol Metab 89: 4351-4358, 2004)
Acute ingestion of both WH and CS after exercise resulted in similar increases in muscle protein net balance, resulting in net muscle protein synthesis despite different patterns of blood amino acid responses.
EAA improved LBM and basal muscle protein synthesis in older individuals. The acute anabolic response to EAA supplementation is maintained over time and can improve LBM, possibly offsetting the debilitating effects of sarcopenia.
Timing of nutrient ingestion has been demonstrated to influence the anabolic response of muscle following exercise. Previously, we demonstrated that net amino acid uptake was greater when free essential amino acids plus carbohydrates were ingested before resistance exercise rather than following exercise. However, it is unclear if ingestion of whole proteins before exercise would stimulate a superior response compared with following exercise. This study was designed to examine the response of muscle protein balance to ingestion of whey proteins both before and following resistance exercise. Healthy volunteers were randomly assigned to one of two groups. A solution of whey proteins was consumed either immediately before exercise (PRE; n = 8) or immediately following exercise (POST; n = 9). Each subject performed 10 sets of 8 repetitions of leg extension exercise. Phenylalanine concentrations were measured in femoral arteriovenous samples to determine balance across the leg. Arterial amino acid concentrations were elevated by ∼50%, and net amino acid balance switched from negative to positive following ingestion of proteins at either time. Amino acid uptake was not significantly different between PRE and POST when calculated from the beginning of exercise (67 ± 22 and 27 ± 10 for PRE and POST, respectively) or from the ingestion of each drink (60 ± 17 and 63 ± 15 for PRE and POST, respectively). Thus the response of net muscle protein balance to timing of intact protein ingestion does not respond as does that of the combination of free amino acids and carbohydrate
Background: Patients who suffer severe burns are at higher risk for local and systemic infections. In recent years, emerging resistant pathogens have forced burn care providers world wide to search for alternative forms of treatment. Multidrug-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter spp., and various fungal strains have been the major contributors to the increase in morbidity and mortality rates. Multi-drugresistant S. aureus remains the major cause of gram-positive burn wound infections world wide. Treatment strategies include rigorous isolation protocols and new types of antibiotics where necessary. Methods: We reviewed 398 severely burned patients (burns >40% total body surface area [TBSA]) admitted to our hospital between 2000 and 2006. Patients who did not contract multi-drug-resistant gram-negative organisms during their hospital course and received our standard antibiotic regimen-vancomycin and piperacillin= tazobactam-served as controls (piperacillin=tazobactam; n ¼ 280). The treatment group consisted of patients who, during their acute hospital stay, developed infections with multi-drug-resistant gram-negative pathogens and were treated with vancomycin and colistin for at least three days (colistin; n ¼ 118). Results: Gram-negative organisms continue to cause the most severe infections in burn patients. Colistin has reemerged as a highly effective antibiotic against multiresistant Pseudomonas and Acinetobacter infections of burns. Patients who required colistin therapy had a significantly larger average total and full-thickness burn than patients treated with piperacillin=tazobactam and vancomycin, and the mortality rate was significantly higher in the colistin group (p < 0.05). However, there was no significant difference between the colistin and piperacillin= tazobactam groups in the incidence of neurotoxicity, hepatic toxicity, or nephrotoxicity. The main fungal pathogens in burn patients are Candida spp., Aspergillus spp., and Fusarium spp. A definitive diagnosis is more difficult to obtain than in bacterial infections. Amphotericin B and voriconazole remain the two most important anti-fungal substances in our practice. Conclusions: Innovations in fluid management, ventilatory support, surgical care, and antimicrobial therapy have contributed to a significant reduction in morbidity and mortality rates in burn patients. Vancomycin and clindamycin are the two most important reserve antibiotics for methicillin-resistant Staphylococcus aureus infection. Oxazolidinones and streptogramins have showed high effectiveness against gram-positive infections. Colistin has re-emerged as a highly effective antibiotic against multiresistant Pseudomonas and Acinetobacter infections. Current challenges include Candida, Aspergillus, and molds. The development of new agents, prudent and appropriate use of antibiotics, and better infection control protocols are paramount in the ongoing battle against multi-resistant organisms.
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