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Protein Catabolism (protein + catabolism)
Selected AbstractsNutritional supplements combined with dietary counselling diminish whole body protein catabolism in HIV-infected patientsEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 1 2000Berneis Background Weight loss and protein malnutrition are frequent complications in HIV-infected patients. The effect of an oral nutritional supplement combined with nutritional counselling on whole body protein metabolism was assessed. Materials and methods HIV-infected individuals with a body mass index < 21 kg m,2 or CD4-T cells < 500 , L,1 in stable clinical condition were randomly allocated to [ 1] receive either oral nutritional supplements (containing 2510 kJ, complete macro- and micronutrients) and dietary counselling (n = 8), or [ 2] identical monitoring but no supplements or specific nutritional advice (controls, n = 7). Whole body leucine kinetics and leucine oxidation rate were determined by [1,13C]-leucine infusions and lean and fat mass were measured before and 12 weeks after intervention. Results Leucine oxidation (protein catabolism) decreased in the group receiving nutritional intervention from 0.33 ± 0.02 to 0.26 ± 0.02 ,mol kg,1 min,1 after 12 weeks (P < 0.05; P < 0.05 vs. control group) but remained unchanged in the control group. Whole body leucine flux showed a tendency to decrease in the intervention group from 1.92 ± 0.19 to 1.73 ± 0.14 ,mol kg,1 min,1 (P = 0.07) and remained unchanged in the control group (2.21 ± 0.16 and 2.27 ± 0.14 ,mol kg,1 min,1, respectively). Lean body mass determined by bioelectrical impedance analysis increased in the nutritional intervention group from 84 ± 2 to 86 ± 2 per cent (P < 0.05) and fat mass decreased from 17 ± 2 to 14 ± 2 per cent (P < 0.05) of total body weight whereas neither mass changed in the control group. Nutritional intervention had no significant effect on lymphocyte CD4 counts, on plasma TNFR 55, TNFR 75 and ILR 2 concentrations and on quality of life. Conclusions The data demonstrate an anticatabolic effect of nutritional supplements combined with dietary counselling in HIV-infected subjects. They suggest that diminished whole body protein catabolism resulted in a change of body composition (increased lean mass, decreased fat mass). [source] The ubiquitin-proteasome system and its role in ethanol-induced disordersADDICTION BIOLOGY, Issue 1 2002Terrence M. Donohue Jr The levels of these proteins are controlled by their rates of degradation. Similarly, protein catabolism plays a crucial role in prolonging cellular life by destroying damaged proteins that are potentially cytotoxic. A major player in these catabolic reactions is the ubiquitin-proteasome system, a novel proteolytic system that has become the primary proteolytic pathway in eukaryotic cells. Ubiquitin-mediated proteolysis is now regarded as the major pathway by which most intracellular proteins are destroyed. Equally important, from a toxicological standpoint, is that the ubiquitin-proteasome system is also widely considered to be a cellular defense mechanism, since it is involved in the removal of damaged proteins generated by adduct formation and oxidative stress. This review describes the history and the components of the ubiquitin-proteasome system, its regulation and its role in pathological states, with the major emphasis on ethanol-induced organ injury. The available literature cited here deals mainly with the effects of ethanol consumption on the ubiquitin-proteasome pathway in the liver. However, since this proteolytic system is an essential pathway in all cells it is an attractive experimental model and therapeutic target in extrahepatic organs such as the brain and heart that are also affected by excessive alcohol consumption. [source] Restoration of body mass in King Penguins after egg abandonment at a critical energy depletion stage: early vs late breedersJOURNAL OF AVIAN BIOLOGY, Issue 4 2001Jean-Patrice Robin In fasting-incubating seabirds, it has been proposed that egg abandonment and refeeding should be induced when a low body mass (BM) threshold is attained, thus ensuring adult survival at the expense of immediate breeding. In the context of life-history trade-offs in long-lived birds, we have tested this hypothesis by comparing short-term survival and restoration of BM in King Penguins Aptenodytes patagonicus that abandoned their egg to those that were relieved normally by their mate at the end of the first incubation shift. Since King Penguins have an extended laying period, the possible influence of seasonal factors was also examined by comparing early and late breeders. Forty incubating males were experimentally forced to fast until egg abandonment by preventing relief by the female. At egg abandonment of both early and late breeding males, BM was below the BM threshold, fasting duration was eight days (about 30%) longer than for relieved birds, and plasma uric acid level was elevated (signature of increased body protein catabolism, phase III of fasting). All abandoning birds survived and came back from sea at a BM similar to that of relieved penguins. The duration of the foraging trip of abandoning early breeders was the same as that of relieved birds, and some abandoning birds engaged in a new breeding attempt. Abandoning late breeders, however, made foraging trips twice as long as those of relieved males. This difference can be explained by time constraints rather than nutritional constraints, abandoning early breeders having enough time left in the breeding season to engage in a new breeding attempt in contrast to abandoning late breeders. These observations lend support to the suggestion that not only BM but also an internal clock intervene in the decision to engage in breeding or not. By preventing a lethal energy depletion ashore and by acting at a fasting stage where the capacity to restore BM at sea is unaffected, abandonment at a low body condition threshold plays a major role in the trade-off between adult penguin survival and reproduction. [source] Presence of methylated arginine derivatives in orthotopic human liver transplantation: Relevance for liver functionLIVER TRANSPLANTATION, Issue 1 2003Paloma Martín-Sanz Orthotopic liver transplantation (OLT) is a frequent option in the treatment of liver diseases. During the cold ischemia period of the donor liver, there is an accumulation of metabolites that are potent inhibitors of the cytokine-inducible and endothelial nitric oxide synthase isoenzymes. We identified the presence of L - N -monomethylarginine and asymmetric dimethylarginine (ADMA) as the main inhibitors by means of analytic high-pressure liquid chromatography and mass spectrometry techniques. An average ADMA concentration of 450 ,mol/L was measured in the preservation medium of donor livers with poor outcomes after OLT. A statistically significant relationship was observed between the concentration of methylated arginine derivatives in the graft and liver function after OLT. These data suggest that measurement of methylated arginine, released after liver protein catabolism, might provide an indication of functional status of the liver that can help the development of strategies intended to improve graft viability. [source] Anesthetic implications of ornithine transcarbamylase deficiencyPEDIATRIC ANESTHESIA, Issue 7 2010ANDREA P. DUTOIT MD Summary Background:, Ornithine transcarbamylase deficiency (OTCD) is an X-linked urea cycle disorder associated with potentially fatal episodes of hyperammonemia. Children with OTCD often require anesthesia. There is insufficient information regarding perioperative complications and optimal management of anesthesia in these patients. Aim:, To retrospectively review the medical records of children with OTCD to ascertain the nature and frequency of peri-procedural complications. Methods/Materials:, The electronic medical records of Mayo Clinic patients with OTCD who underwent anesthesia between the dates of January 2003 and September 2009 were reviewed. Results:, Nine patients with OTCD underwent 25 anesthetics using a variety of anesthetic techniques, including four major surgeries. Eleven procedures were performed prior to OTCD diagnosis and those patients were not receiving therapy for a urea cycle disorder. In the other cases, patients were on a variety of therapies for OTCD. Fourteen patients were outpatient procedures. Clinical signs of postoperative metabolic decompensation did not occur. Conclusions:, In this series, patients with OTCD tolerated anesthesia well. Choice of perioperative management of OTCD and the choice of anesthetic technique should be individualized and based on clinical circumstances, but should have the underlying aim of minimizing protein catabolism. It appears patients with stable OTCD may undergo minor procedures as outpatients safely. [source] Acrodermatitis Enteropathica-like Dermatosis Associated with Ornithine Transcarbamylase DeficiencyPEDIATRIC DERMATOLOGY, Issue 4 2007José C. Pascual M.D. Ornithine transcarbamylase deficiency is the most frequent urea cycle disorder. It is a hereditary-X-linked disease with over 150 mutations described (1).Ornithine transcarbamylase deficiency causes vomiting, lethargy, hyperventilation, and even death, mainly in the neonatal period (2). Ammonia, an extremely toxic molecule for the organism, is generated during protein catabolism and is accumulated in patients with this deficiency. Part of the treatment consists of a low-protein diet, to avoid hyperammonemia episodes, which can even have a fatal outcome. Patients can become deficient in several amino acids, either through the low-protein diet or directly through the primary enzyme deficiency; this in turn can cause an acrodermatitis enteropathica-like dermatosis. [source] Proteomic analysis of the pH response in the fungal pathogen Candida glabrataPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 3 2008Pia Schmidt Abstract Micro-organisms must adapt to environmental change to survive, and this is particularly true for fungal pathogens such as Candida glabrata. C. glabrata is found both in the environment and in diverse niches in its human host. The ambient pH of these niches varies considerably, and therefore we have examined the response of C. glabrata to changes in ambient pH using a proteomic approach. Proteins expressed in C. glabrata cells growing at pH,4.0, 7.4 or 8.0 were compared by 2-DE, and 174 spots displaying reproducible and statistically significant changes in expression level were identified by peptide mass fingerprinting, thereby extending our 2-DE map of the C. glabrata proteome to a total of 272 identified spots. Proteins involved in glucose metabolism, the TCA cycle, respiration and protein synthesis were expressed at lower levels during growth at pH,7.4 and/or 8.0, whereas proteins involved in stress responses and protein catabolism were expressed at higher levels under these alkaline conditions. Our data suggest that C. glabrata perceives low pH as less stressful than higher pH. This contrasts with another opportunistic fungal pathogen of humans, Candida albicans [source] Natural abundance of 15N and 13C in fish tissues and the use of stable isotopes as dietary protein tracers in rainbow trout and gilthead sea breamAQUACULTURE NUTRITION, Issue 1 2009M. BELTRÁN Abstract For developing efficient diets, two sets of experiments examined whether the use and allocation of dietary protein can be traced by labelling with stable isotopes (15N and 13C) in two culture fish (Oncorhynchus mykiss and Sparus aurata). In the first experiment, natural abundance and tissue distribution of these isotopes were determined, by measuring the ,13C and ,15N values by isotopic ratio mass spectrometry, in fingerlings (14,17 g) adapted to diets differing in the percentage of fish meal replacement by plant protein sources. For both species, ,15N and ,13C were greater in tissues with higher protein and lower lipid content. Delta 15N of diets and tissues decreased as replacement increased, suggesting ,15N can be used as a marker for dietary protein origin. The 15N fractionation (,15N fish , ,15N diet) differed between groups, and could thus be used to indicate protein catabolism. In the second experiment, fish (75,90 g) of each species ingested a diet enriched with 15N-protein (10 g kg,1 diet) and 13C-protein (30 g kg,1 diet). These proportions were suitable for determining that the delta values of tissue components were high enough above natural levels to allow protein allocation to be traced at 11 and 24 h after feeding, and revealed clear metabolic differences between species. [source] Nutritional Effect of Dialysis TherapyARTIFICIAL ORGANS, Issue 3 2003Tsutomu Sanaka Abstract: The prognosis of patients with end-stage renal disease has been improved by the recent remarkable advances in medical and engineering technology. However, there are still many unsolved problems in the clinical field. One of the problems is an intractable malnutrition characterized by clinical manifestations including hypoproteinemia and decrease in muscular volume, which is associated with deterioration in the quality of the patient's life. Malnutrition in hemodialysis patients involves abnormal energy metabolism and aberrant amino acid metabolism. In the most malnourished patients, immunodefense mechanisms and homeostasis are disrupted, greatly influencing the prognosis. Moreover, when the performance of dialyzer used is too high, the dialysis treatment might remove a necessary nutrient for the patient. There is also a possibility that the protein catabolism is accelerated when the biocompatibility is inferior. On the other hand, in malnutri-tion, the circulating level of insulin-like growth factor-1 (IGF-1) falls while the level of insulin-like growth factor binding protein-1 (IGFBP-1) is remarkably increased. It has been recognized that IGF-1 and IGFBP-1 are indicators reflecting the initiation of a malnutritional state in patients with chronic renal failure, although there are many indicators such as albumin, prealbumin, and anthropometric measurement for nutritional assessment. We have suggested that r-hGH and IGF-1 improve the malnutritional state by alleviating hypoproteinemia and abnormality of serum amino acid profile in uremic patients on hemodialysis. The serum IGF-1/IGFBP-1 ratio is useful not only as a nutritional parameter but also as a predicting index of responsiveness to r-hGH. It is necessary to examine the problem from various angles to improve malnutrition in the dialysis patient, while considering the above mentioned. [source] | |||||||||||||