SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
This retrospective study demonstrates a low frequency of parenteral nutrition-associated direct bilirubinemia within a population of extremely low birthweight neonates (1000 gm or less) exposed to a pediatric amino acid mixture.
In the dietetic treatment of phenylketonuric patients phenylalanine free amino acid mixtures are given to meet the protein requirement of the patient. In four healthy probands we tested the metabolic effects of four different PKU-preparations given in variable amounts ingested with carbohydrate and fat containing meals. We determined glucose, insulin, amino acids, and urea in blood. Following the amino acid load we saw an increased insulin output with a hypoglycemic reaction or, with smaller amounts a lack of the normal postprandial blood glucose increase. Hyperaminoacidemias depended on the amount of amino acids ingested. The increase of blood urea found suggests that part of the amino acids were degraded. To compare the results we studied a PKU-patient. He showed corresponding but milder effects.
Given evidence of a hypocholesterolemic effect in rats, soy protein compared with casein showed the following effects on cholesterol dynamics: a) lower cholesterol absorption and greater fecal steroid excretion, b) more rapid turnover of serum cholesterol, c) a marked size reduction of the rapidly exchangeable cholesterol pool (pool A) through a significant increase in the removal rate in that compartment without influencing the production rate, and d) greater hepatic sterogenesis both in vitro and in vivo. In contrast, the amino acid mixture equivalent to soy protein compared with casein-type mixture showed: a) no effects on cholesterol absorption and fecal steroid excretion, b) no effects on the turnover of serum cholesterol, c) the reduction of pool A size as a result of decreased production, and d) the reduction of hepatic steroidogenesis in vitro, but not in vivo. These results indicate that decreased intestinal absorption of cholesterol, and increased fecal steroid excretion are primarily responsible for the antihypercholesterolemic effect of soy protein compared with casein. The fecal loss of steroids far outweighs the activation of hepatic steroidogenesis. In the case of the soy protein-type amino acid mixture, the depression of hepatic cholesterol synthesis seems accountable for reducing serum cholesterol levels.
Explore the source record for details and available documents.
BACKGROUND: To assess the acceptability and nutritional adequacy of a new phenylalanine-free amino acid mixture (Phenylade-Dietetic Metabolic Food). METHODS: Twenty PKU patients (aged 2.6-10 years) diagnosed and followed by our Department. The children were given this product for a minimum of 4 and a maximum of 12 months. The clinical control has been carried out before treatment and then every 3 months. The biochemical parameters included: quantitative plasma amino acids, hematologic measurements of nutritional adequacy folic acid and vitamin B12. RESULTS: All patients (except one) found this new product to be an acceptable alternatives as to taste and convenience to the previous low phenylalanine protein substitutes. CONCLUSIONS: Normal growth was maintained.
This study examined the effects of an amino acid mixture supplement on physiological response and ratings of perceived exertion during submaximal cycle-ergometer exercise in 15 healthy, untrained male students. Subjects performed submaximal sustained exercise (oxygen uptake at anaerobic threshold: 54.6 +/- 12.5% of maximum oxygen uptake capacity) with a cycle-ergometer ride for 60 min. after resting for 1 min. and unloaded cycling for 2 min. They drank either a 380-ml supplement containing vespa amino acids or a lemon-flavored placebo at 30 min. before starting exercise in a double-blind design. The subjects participated in both experiments over a 1-wk. interval. Oxygen uptake, respiratory exchange ratio, heart rate, ratings of perceived exertion, and plasma lactate concentration were measured during the exercise. The change-rate of respiratory exchange ratio for the Supplement group was significantly lower than that for the Placebo group at 10 min. after starting exercise. The change-rate of the ratings of perceived exertion for the Supplement group was significantly lower than that for the Placebo group at 50 min. after starting exercise. There were no significant changes in the rates in oxygen uptake, heart rate, and plasma lactate concentration between groups. We inferred that ingesting the supplement before starting exercise has a significant effect on the respiratory exchange ratio and ratings of perceived exertion during submaximal sustained exercise for 60 min. but not on oxygen uptake, heart rate, and plasma lactate concentration.
Ninety infants and children received total parenteral nutrition with a mixture of glucose, crystalline amino acids, vitamins, electrolytes, and minerals. The mixture was generally well-tolerated with a minimum of complications. The intravenous regimen produced positive nitrogen balance and weight gain in the majority of subjects. The amino acids provided maintained the protein pool in these patients as a further indication of utilization. Mild, transient, asymptomatic elevations in blood urea nitrogen occurred in a few low-birth-weight infants who probably received insufficient nonprotein calories relative to their needs. Hypophosphatemia and acidosis did not occur. It is concluded that this regimen is safe, effective method of providing total parenteral nutrition, provided that adequate nonprotein calories are provided.
The clinical effectiveness of alvesin, a mixture of pure amino acids, balanced by the amino acid composition, was studied in the treatment of patients with chronic diseases of the small intestine. The drug was well tolerated by the patients after its parenteral administration. A high clinical effect of alvesin was recorded in 98 patients suffering from chronic enteritis, celiac disease, general variable immunodeficiency. The optimal dose of the drug was determined.
The standard method of peptide library synthesis involves coupling steps in which a single amino acid is reacted with a mixture of resin-bound amino acids. The more recently described positional scanning strategy (in which each position in the peptide sequence is occupied in turn by a single residue) is different since it involves the coupling of mixtures of amino acids to mixtures of resin-bound amino acids. In the present study, we analyze the compounds produced under these conditions measuring coupling rates and amounts of formed products, using mainly UV, HPLC, LC/MS and MS/MS techniques. Our data do not permit to conclude that the resulting libraries are complete. Indeed, our analytical data indicate that a large part of the di-, tri- and tetrapeptides synthesized with this method are not present in the final mixture. Although chemical compensation (in which poor coupling kinetics is compensated by a larger excess of the incoming amino acid) has been thought to counterbalance these biases, our experiments show that the compensation method does not take into account the crucial influence of the resin-bound amino acid and that even the dipeptide libraries obtained in this way are far from completeness. The present work provides strong evidence that the coupling of mixtures of amino acids to resin-bound residues, which is required by the positional scanning strategy, results in incomplete and/or non-equimolar libraries. It also clearly confirms that coupling rates in solid-phase peptide synthesis are dependent on the nature of both the incoming and the immobilized amino acid.
The importance of complete or almost complete intake of the recommended amount of phenylalanine-free amino acid mixture (AAM) for control of blood phenylalanine level in patients being treated for phenylketonuria (PKU) has not been universally appreciated. We observed the effect of complete intake of AAM on plasma phenylalanine levels during hospitalization in 6 patients with PKU (5 pregnant women with PKU and 1 child) who had poor metabolic control because of less than full compliance with prescribed AAM intake. Before hospitalization, all but 1 of the patients had blood phenylalanine levels above 1,000 mumol/L; in 1 patient the blood phenylalanine level was 703 mumol/L. During 9 periods of observation in the 6 patients, the levels of plasma phenylalanine decreased to the recommended range of below 360 mumol/L within 2 to 6 days of hospitalization. These experiences indicate a close relationship between compliance with prescribed AAM intake and control of blood phenylalanine level. We propose that hospitalization be considered when patients with PKU who are consuming a phenylalanine-restricted diet fail to maintain blood phenylalanine levels in the targeted range despite reported compliance with the prescribed intake of dietary phenylalanine and AAM.
A highly active fraction of rat liver oligonucleosome DNA has been isolated and studied by means of thermal denaturation after induction by amino acid mixture or hydrocortisone. A considerable redistribution of DNA content has been shown in sucrose gradient fractions during these forms of induction. The changes are revealed in melting temperature, differential melting profile of DNA, isolated from actively transcribed chromatine fractions. Analysis of melting profiles shows changes of GC content of oligonucleosome DNA, suggesting that there are differences in activation during two studied forms of induction.
A mixture of eighteen protein amino acids was heated in sea water medium enriched with transition metal ions. Small granules were obtained as precipitates. Both dialyzable polymers and undialyzable polymers were obtained from the supernatant. Dialyzable polymers yielded mainly Glu, Asp, Ser, and Thr on hydrolysis; undialyzable polymers (C, 29.45; H, 3.87; N, 4.87; and ash, 31.5 wt%) yielded Thr, Asp, Glu, Gly, Leu, Ser, Lys, Pro, His, Phe, and a few unidentified ninhydrin positive peaks after acid hydrolysis. Five wt% of the undialyzable polymers con-ist of acid-hydrolyzable protein amino acids.
Maillard products of 1:1 solid mixtures of glucose-amino acid heated at 200 degrees C for 5 min induced single-strand breaks of DNA after incubation at 37 degrees C and pH 7.4 overnight. The products of Gly, His, Trp, Tyr, Phe and CySH transformed a plasmid supercoiled DNA (form I) into an open circular relaxed form (form II) and a linear form (form III). The breaking activity of the product of CySH was the highest. The product of Tyr caused fragmentation of single-stranded DNA, but did not cleave double-stranded linear DNA. The breaking activity of the product of Tyr was little or not at all inhibited by scavengers of singlet oxygen, hydroxyl radical, superoxide and hydrogen peroxide. Aqueous solutions of the products of all amino acids except CySH emitted chemiluminescence, which was partly due to singlet oxygen. High-performance liquid chromatography of the product of Tyr showed that the substances responsible for the DNA-breaking activity were eluted in a broad range, whereas those for chemiluminescence were eluted in an overlapped sharp peak. The Maillard reaction of glucose-amino acid in a solid state produced substances having DNA-breaking activity together with those generating single oxygen and emitting chemiluminescence.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.