Elective abdominal operations alter the free amino acid content of the human intestinal mucosa.

Objective: To assess the impact of a standard moderately severe surgical operation on the mucosal amino acid content of the duodenum and the colon.

Design: Open study.

Setting: University hospital, Sweden.

Intestinal amino acid content in critically ill patients.

Background: The purpose of the study was to determine the concentrations of free amino acids and the total protein content of the human intestinal mucosa during critical illness.

Methods: The free amino acid and protein concentrations in endoscopically obtained biopsy specimens from the duodenum and the distal colonic segments were determined on 19 critically ill patients. The free amino acids were separated by ion exchange chromatography and detected by fluorescence, and the protein content was quantified by the method of Lowry.

Laparoscopic cholecystectomy does not prevent the postoperative protein catabolic response in muscle.

Objective: The authors determined the effect of laparoscopic cholecystectomy on protein synthesis in skeletal muscle. In addition to a decrease in muscle protein synthesis, after open cholecystectomy, the authors previously demonstrated a decrease in insulin sensitivity. This study on patients undergoing laparoscopic and open surgery, therefore, included simultaneous measurements of protein synthesis and insulin sensitivity.

The effects of a new amino-acid dipeptide solution on nitrogen balance and humoral growth factors in the postoperative state in man.

27 patients admitted for elective abdominal surgery were allocated to receive postoperative total parenteral nutrition supplemented with glutamine (glycyl-glutamine) and tyrosine (glycyl-tyrosine) containing dipeptides (DP-Gln 20; 0.16 g glutamine/kg BW/24 h) or isonitrogenous Vamin 18 for 5 days. The aim was to evaluate safety and effects on short-life plasma proteins, nitrogen balance, 3-methylhistidine excretion and alimentary growth factors in plasma.

Human skeletal muscle protein: effect of malnutrition, elective surgery and total parenteral nutrition.

1. The concentration of alkali-soluble protein, DNA and RNA in percutaneous muscle biopsy specimens was analysed. Tissue alkali-soluble protein/DNA ratio is a measure of muscle protein concentration, while tissue RNA/DNA ratio may reflect the capacity for protein synthesis.

Alpha-ketoglutarate for myocardial protection in heart surgery.

A low myocardial content of alpha-ketoglutarate during heart surgery might aggravate ischaemic injury. 24 men undergoing coronary surgery participated in a randomised controlled study. 28 g alpha-ketoglutarate was added to blood cardioplegia for intermittent antegrade intracoronary perfusion in 13 cases.

Long-term effects of postoperative total parenteral nutrition supplemented with glycylglutamine on subjective fatigue and muscle protein synthesis.

Seventeen patients undergoing elective open cholecystectomy were given conventional total parenteral nutrition either with (nine patients) or without (eight) glutamine supplementation of 20 g/day for 3 days after surgery and thereafter ordinary food for the following 27 days. Muscle protein synthesis, as assessed by the total concentration of ribosomes, decreased in control patients on day 3 following surgery and remained low on days 10, 20 and 30 (P < 0.05).

Stress hormone and amino acid infusion in healthy volunteers: short-term effects on protein synthesis and amino acid metabolism in skeletal muscle.

To study the immediate effects of stress hormones and intravenous amino acid support, healthy male volunteers were administered a stress-hormone infusion including epinephrine, cortisol, and glucagon either alone (Triple, n = 8) or combined with a balanced glutamine-free amino acid solution (Triple AA, n = 8) over a period of 6 hours. The amino acid infusion was started 2 hours after the hormone infusion. A third group (AA, n = 8) received the balanced amino acid solution alone.

The separate and combined effect of leucine and insulin on muscle free amino acids.

The effect of insulin and leucine on amino acid and protein metabolism in muscle is not fully understood. To characterize their separate and combined effects on free amino acids in muscle and plasma, 11 volunteers received an infusion of either leucine (1 g h-1, Group 1) or glucose (20 g h-1, Group 2) for 2 h followed by a combination of the two infusions for an additional 2-h period. In muscle both the leucine infusion and the leucine plus glucose infusion increased the concentration of free leucine significantly, while the sum of the other branched chain amino acids (BCAA), of the aromatic amino acids and of the basic amino acids decreased.

Long-term effect of glycyl-glutamine after elective surgery on free amino acids in muscle.

In order to evaluate the long-term effect of total parenteral nutrition supplemented with glutamine after surgery, patients (n = 17) undergoing elective abdominal surgery were randomized into two groups and studied for 30 days after surgery. During the 3 days immediately after surgery, one group (n = 8) was given total parenteral nutrition including a conventional amino acid solution (control group). The other group (n = 9) was given isocaloric and isonitrogenous total parenteral nutrition including the same amino acid solution supplemented with the dipeptide, glycyl-glutamine (GLN group).

Short-term starvation alters the free amino acid content of the human intestinal mucosa.

1. The effects of short-term starvation and refeeding on the free amino acid concentrations of the intestinal mucosa were characterized in male subjects (n = 6), using endoscopically obtained biopsy specimens from the duodenum and from all four segments of the colon. 2.

Measurement of tissue protein synthesis rates in vivo: a critical analysis of contrasting methods.

The extension of the flooding method for measuring the rate of protein synthesis, from animal to human tissues, has led to criticism. This is based on the observation that in human muscle, unlike animal tissues, the rate of synthesis in the fasting state measured with constant infusion is lower than that obtained with the flooding technique. Moreover, incorporation of infused tracer can be enhanced with a simultaneous flood, although an inhibition of incorporation has also been reported.

Free amino acids in biopsy specimens from the human colonic mucosa.

The content of free amino acids and total protein was determined in endoscopic biopsy specimens from the rectum, descending colon, transverse colon, and ascending colon in 10 patients. The amino acids were quantified by ion-exchange chromatography and were detected by fluorescence. The amino acid pattern and the rank order of the individual amino acids in the colon were different compared to those in plasma.

The content of free amino acids in the human duodenal mucosa.

The free amino acid concentrations and the total protein content of the duodenal mucosa were determined in biopsy specimens obtained during endoscopic examinations in 10 healthy subjects. The amino acids were separated and quantified by ion exchange chromatography using fluorescence detection. The protein content was analysed according to Lowry.

Effect of growth hormone on muscle and protein in critically ill patients.

In summary, the effects of protein metabolism of the provision of additional GH are well documented in critically ill patients. Nitrogen balance improves as urea production is diminished. The crucial question is whether this lowers the availability of glutamine for cells dependent on it in critical illness.

Stress hormones alter the pattern of free amino acids in human skeletal muscle.

Stress hormones were infused for 6 h in healthy volunteers (n = 32). Free amino acid concentrations were determined in plasma and in skeletal muscle biopsy specimens. A triple hormone combination of adrenaline, cortisol, and glucagon raised the level of alanine in muscle, while glutamine, glutamate, the branched chain amino acids, the aromatic amino acids, and the basic amino acids decreased.

Muscle protein synthesis after operation: effects of intravenous nutrition.

Objective: To assess the effect of an elective abdominal surgical operation (open cholecystectomy) on the rate of protein synthesis in skeletal muscle in humans.

Design: Prospective random control trial.

Setting: University hospital.

Temporal responses of protein synthesis in human skeletal muscle to feeding.

In attempting to evaluate alterations in metabolic responses to dietary nutrients that occur in pathological conditions in man, it is first necessary to understand normal metabolic responses. The present study set out to determine the temporal responses of protein synthesis in the skeletal muscle of healthy subjects to the consumption of food. Sequential measurements of protein synthesis in quadriceps muscle were made in eight subjects by injection of 0.

Biosynthetic human growth hormone preserves both muscle protein synthesis and the decrease in muscle-free glutamine, and improves whole-body nitrogen economy after operation.

As a reproducible human trauma model, patients (n = 17) undergoing elective cholecystectomy were studied for 3 postoperative days. They were randomly allocated to receive either recombinant human growth hormone (hGH; 0.3 U/kg/24 hours) or placebo together with total parenteral nutrition, including 0.

Short-term starvation decreases skeletal muscle protein synthesis rate in man.

The rate of protein synthesis in skeletal muscle was determined in the post-absorptive state and after 3 days of starvation in healthy volunteers. The flooding dose technique employing intravenous injection of (1-13C)leucine (0.05 g kg-1) was used and incorporation of isotope into muscle protein was measured by taking percutaneous biopsies at 0 and 90 min.

Free amino acids in plasma and muscle during 24 hours post-operatively--a descriptive study.

Intracellular amino acids in skeletal muscle show a specific concentration pattern on the third post-operative day. The temporal development of these changes has not been clarified. Here the amino acid concentrations in skeletal muscle were studied during the first post-operative day in fourteen patients undergoing elective abdominal surgery.