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Chain Amino Acids (chain + amino_acids)
Selected AbstractsForearm and leg amino acid metabolism in the basal state and during combined insulin and amino acid stimulation after a 3-day fastACTA PHYSIOLOGICA, Issue 3 2009J. Gjedsted Abstract Aim:, Fasting is characterized by a progressive loss of protein, but data on protein kinetics are unclear and few have studied the effects of re-feeding. The present study was designed to test the hypothesis that a combined infusion of insulin and amino acids after fasting would induce compensatory increases in protein synthesis and reductions in protein breakdown at the whole body level and in muscle. Methods:, We included 10 healthy male volunteers and studied them twice: (1) in the post-absorptive state and (2) after 72 h of fasting. Amino acid kinetics was measured using labelled phenylalanine and tyrosine, whole body energy expenditure was assessed and urea nitrogen synthesis rates were calculated. Results:, After fasting we observed an increase in arterial blood concentration of branched chain amino acids and a decrease in gluconeogenic amino acids (P < 0.05). Isotopically determined whole body, forearm and leg phenylalanine fluxes were unaltered apart from a 30% decrease in phenylalanine-to-tyrosine conversion (2.0 vs. 1.4 ,mol kg,1 h,1, P < 0.01). During infusion of insulin and amino acids, amino acid concentrations increased. Conclusion:, Our data indicate that after a 72-h fast basal and insulin/amino acid-stimulated regional phenylalanine fluxes in leg and forearm muscle are unaltered. During fasting concentrations of gluconeogenic amino acids decrease and hepatic and/or renal phenylalanine-to-tyrosine conversion decreases. Thus, as opposed to glucose and lipid metabolism, fasting does not induce insulin resistance as regards amino acid metabolism. [source] 17, -Hydroxysteroid dehydrogenase type 11 is a major peroxisome proliferator-activated receptor ,-regulated gene in mouse intestineFEBS JOURNAL, Issue 20 2004Kiyoto Motojima In order to study the role of peroxisome proliferator-activated receptor , in mouse intestine, its agonist-induced proteins were identified by peptide mass fingerprinting followed by Northern blot analysis using their cDNAs. One of the most remarkably induced proteins was identified as 17,-hydroxysterol dehydrogenase type 11. Its very rapid induction by various agonists was most efficient in intestine and then in liver. These findings together with recently reported results showing the enzyme family's wide substrate spectrum, including not only glucocorticoids and sex steroids but also bile acids, fatty acids and branched chain amino acids, suggest new roles for both peroxisome proliferator-activated receptor , and 17,-hydroxysterol dehydrogenase type 11 in lipid metabolism and/or detoxification in the intestine. [source] Guidelines for the treatment of chronic hepatitis and cirrhosis due to hepatitis B virus infection for the fiscal year 2008 in JapanHEPATOLOGY RESEARCH, Issue 1 2010Hiromitsu Kumada In the 2008 guidelines for the treatment of patients with cirrhosis, who are infected with hepatitis B virus (HBV), the main goal is to normalize levels of alanine and aspartate aminotransferases by eliminating HBV or reducing viral loads. In patients with compensated cirrhosis, the clearance of HBV from serum is aimed for by entecavir, as the main resort, for histological improvement toward the prevention of hepatocellular carcinoma (HCC). In patients with decompensated cirrhosis, by contrast, meticulous therapeutic strategies are adopted for the reversal to compensation, toward the eventual goal of decreasing the risk of HCC. For maintaining liver function and preventing HCC, branched chain amino acids and nutrient supplements are applied, in addition to conventional liver supportive therapies. For patients with chronic hepatitis B, separate guidelines are applied to those younger than 35 years and those aged 35 years or older. Even for patients with chronic hepatitis who are negative for hepatitis e antigen (HBeAg), but who harbor HBV DNA in titers of 7 log copies/mL or more, a "drug-free state" is aimed for by sequential treatment with interferon (IFN) plus entecavir as the first line. For patients with chronic hepatitis B aged 35 years or older, who are HBeAg-negative and carry HBV DNA in titers of less than 7 log copies/mL, long-term IFN for 24,48 weeks is adopted anew. To HBeAg-negative patients who have either or both platelet counts of less than 150 × 103/mm3 and less than 7 log copies of HBV DNA, also, long-term IFN for 24,48 weeks is indicated. [source] Guidelines for the treatment of chronic hepatitis and cirrhosis due to hepatitis C virus infection for the fiscal year 2008 in JapanHEPATOLOGY RESEARCH, Issue 1 2010Hiromitsu Kumada In the 2008 guidelines for the treatment of patients with chronic hepatitis C, pegylated interferon (Peg-IFN) combined with ribavirin for 48 weeks are indicated for treatment-naive patients infected with hepatitis C virus (HCV) of genotype 1. Treatment is continued for an additional 24 weeks (72 weeks total) in the patients who have remained positive for HCV RNA detectable by the real-time polymerase chain reaction at 12 weeks after the start of treatment, but who turn negative for HCV RNA during 13,36 weeks on treatment. Re-treatment is aimed to either eradicate HCV or normalize transaminase levels for preventing the development of hepatocellular carcinoma (HCC). For patients with compensated cirrhosis, the clearance of HCV RNA is aimed toward improving histological damages and decreasing the development of HCC. The recommended therapeutic regimen is the initial daily dose of 6 million international units (MIU) IFN continued for 2,8 weeks that is extended to longer than 48 weeks, if possible. IFN dose is reduced to 3 MIU daily in patients who fail to clear HCV RNA by 12 weeks for preventing the development of HCC. Splenectomy or embolization of the splenic artery is recommended to patients with platelet counts of less than 50 × 103/mm3 prior to the commencement of IFN treatment. When the prevention of HCC is at issue, not only IFN, but also liver supportive therapy such as stronger neo-minophagen C, ursodeoxycholic acid, phlebotomy, branched chain amino acids (BCAA), either alone or in combination, are given. In patients with decompensated cirrhosis, by contrast, reversal to compensation is attempted. [source] Blood serum branched chain amino acids and tryptophan modifications in horses competing in long-distance rides of different lengthJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 3-4 2004A. Assenza Summary During long-distance exercise, branched-chain amino acid (BCAA) catabolism could lead to an increase in the blood tryptophan/BCAA ratio and an early onset of ,central fatigue'. Based on these considerations, we studied the modifications of blood serum BCAA and tryptophan (Try) levels in 30 endurance horses competing in rides varying in distance from 20 to 72 km. From all horses, blood samples were drawn just before and just after the end of the ride. Samples were analysed for their leucine (Leu), valine (Val), isoleucine (Iso) and Try levels. Data were processed by anova, using sampling moment and ride as factors, and by LSD post hoc test. Significant differences were recorded among the different distance rides for Leu, Val, Iso, Try, Try/BCAA ratio; the same trend was recorded between samples taken at the start and the end of the race for Val and Leu. The main effect observed was an increase of BCAA levels for all rides, except the 72-km ride; for Try, a significant increase was present in all races, except the 50-km ride. The Try/BCAA ratio decreased in 20- and 50-km races and increased in the others. These data confirm that long-distance exercise involves a mobilization of BCAA. The utilization of BCAA seems to be important in prolonged exercise: in the 72-km ride, we observed a decrease in BCAA blood serum levels, while a major role of Try was indicated by its increase, resulting in a rise of the Try/BCAA ratio. [source] Role of meal carbohydrate content for the imbalance of plasma amino acids in patients with liver cirrhosisJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 8 2007Ewert Schulte-Frohlinde Abstract Background and Aim:, Imbalance of circulating branched chain amino acids (BCAA) versus aromatic amino acids (AAA) and hyperinsulinemia are common metabolic alterations in patients with liver cirrhosis. The aim of this study was to characterize the effect of the carbohydrate component of a protein-rich mixed meal on postprandial plasma concentrations of 21 amino acids, insulin and C-peptide in patients with compensated liver cirrhosis. Furthermore, the effect of a dietary intervention on the metabolic alterations in cirrhotic patients was examined. Methods:, Eighteen patients with cirrhosis and 12 healthy volunteers received a protein-rich meal (pork filet 200 g) with or without carbohydrates (bread 50 g, glucose 20 g). A subgroup of four cirrhotic patients received an isoenergetic (117 kJ/kg bw) carbohydrate-enriched (60%) and -restricted (20%) diet for 7 days each. Results:, In the cirrhotic patients, basal plasma insulin and C-peptide concentrations were significantly elevated. The ingestion of a protein-rich meal without additional carbohydrates led to a significantly greater increase of insulin and C-peptide in the cirrhotic patients compared to controls. Postprandial increases of leucine and isoleucine were reduced, whereas those of phenylalanine were higher in cirrhotic patients. The addition of carbohydrates led to higher insulin and C-peptide plasma concentrations in cirrhotic patients. Postprandial BCAA increases were more impaired in the cirrhotic group after additional carbohydrate ingestion (46%vs 82%). After the carbohydrate-restricted diet for 7 days BCAA plasma levels increased but the BCAA/AAA ratio remained unaltered. Conclusions:, The carbohydrate content of a meal enhances reduction of BCAA plasma concentrations in clinically stable cirrhotic patients. An imbalanced BCAA/AAA ratio cannot be avoided by a carbohydrate-reduced diet alone, supporting mandatory BCAA supplementation. [source] Nerve Tissue-Specific (GLUD2) and Housekeeping (GLUD1) Human Glutamate Dehydrogenases Are Regulated by Distinct Allosteric MechanismsJOURNAL OF NEUROCHEMISTRY, Issue 5 2000Implications for Biologic Function Abstract: Human glutamate dehydrogenase (GDH), an enzyme central to the metabolism of glutamate, is known to exist in housekeeping and nerve tissue-specific isoforms encoded by the GLUD1 and GLUD2 genes, respectively. As there is evidence that GDH function in vivo is regulated, and that regulatory mutations of human GDH are associated with metabolic abnormalities, we sought here to characterize further the functional properties of the two human isoenzymes. Each was obtained in recombinant form by expressing the corresponding cDNAs in Sf9 cells and studied with respect to its regulation by endogenous allosteric effectors, such as purine nucleotides and branched chain amino acids. Results showed that L-leucine, at 1.0 mM, enhanced the activity of the nerve tissue-specific (GLUD2-derived) enzyme by ,1,600% and that of the GLUD1-derived GDH by ,75%. Concentrations of L-leucine similar to those present in human tissues (,0.1 mM) had little effect on either isoenzyme. However, the presence of ADP (10-50 ,M) sensitized the two isoenzymes to L-leucine, permitting substantial enzyme activation at physiologically relevant concentrations of this amino acid. Nonactivated GLUD1 GDH was markedly inhibited by GTP (IC50 = 0.20 ,M), whereas nonactivated GLUD2 GDH was totally insensitive to this compound (IC50 > 5,000 ,M). In contrast, GLUD2 GDH activated by ADP and/or L-leucine was amenable to this inhibition, although at substantially higher GTP concentrations than the GLUD1 enzyme. ADP and L-leucine, acting synergistically, modified the cooperativity curves of the two isoenzymes. Kinetic studies revealed significant differences in the Km values obtained for ,-ketoglutarate and glutamate for the GLUD1- and the GLUD2-derived GDH, with the allosteric activators differentially altering these values. Hence, the activity of the two human GDH is regulated by distinct allosteric mechanisms, and these findings may have implications for the biologic functions of these isoenzymes. [source] Long-term oral branched chain amino acids in patients undergoing chemoembolization for hepatocellular carcinoma: a randomized trialALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 7 2004R. T.-P. Summary Background :,Patients undergoing transarterial chemoembolization for hepatocellular carcinoma have advanced tumour or severe cirrhosis and frequently have associated protein-calorie malnutrition. The role of nutritional supplements for such patients is unclear. Aim :,To investigate, in a randomized controlled trial, any benefit of the long-term administration of branched chain amino acids in patients undergoing chemoembolization for hepatocellular carcinoma. Methods :,Forty-one patients received oral branched chain amino acids for up to four courses of chemoembolization and 43 patients did not receive any nutritional supplement. Morbidity, liver function, nutritional status, quality of life and long-term survival were compared between the two groups. Results :,The administration of branched chain amino acids resulted in a lower morbidity rate compared with the control group (17.1% vs. 37.2%, P = 0.039). In particular, the group given branched chain amino acids showed a significantly lower rate of ascites (7.3% vs. 23.2%, P = 0.043) and peripheral oedema (9.8% vs. 27.9%, P = 0.034). Significantly higher serum albumin, lower bilirubin and a better quality of life were observed after chemoembolization in the group given branched chain amino acids. However, there was no significant difference in survival between the two groups. Conclusions :,Nutritional supplementation with oral branched chain amino acids is beneficial in increasing the serum albumin level, reducing the morbidity and improving the quality of life in patients undergoing chemoembolization for inoperable hepatocellular carcinoma. [source] | |||||||||||||