No abstract

Twenty-two patients undergoing elective abdominal surgery were given total parenteral nutrition (TPN) after the operation. The TPN contained either a conventional amino acid solution supplemented with glutamine or a conventional amino acid solution without supplementation. To study amino acid and protein metabolism, muscle biopsy specimens were taken before surgery and on the third postoperative day. The postoperative decrease in the intracellular concentration of free glutamine was less pronounced in the glutamine group (21.8 +/- 5.5%) than in the control group (38.7 +/- 5.1%; p less than 0.05). The protein synthesis was reflected in the concentration and size distribution of ribosomes. No significant changes in these parameters were seen in the glutamine group after the operation. In the control group, the total concentration of ribosomes fell by 27.2 +/- 8.5% (p less than 0.05), and the relative proportion of polyribosomes fell by 10.6 +/- 2.9% (p less than 0.01). Although there were significant changes in the control group, no significant differences in the changes of these parameters between the two groups were detected. The cumulative nitrogen loss was significantly less in the glutamine group as compared to the control group during the period studied--2.3 +/- 1.4 g versus 8.5 +/- 1.5 g, respectively (p less than 0.01). Administration of glutamine to catabolic patients is advocated.

The effects of the cutaneous application of EMLA cream (a eutectic mixture of lignocaine and prilocaine in their base form) were studied in volunteers. When tested by pin-prick, EMLA cream 2.5% and 5% produced analgesia of the area tested, the cream being most effective if left in contact with the skin for 60 min. The pain produced by the insertion of an i.v. cannula was successfully blocked by the application of this formulation, especially if applied to the antecubital area. Temporary blanching of the skin areas was frequently observed on removal of the occlusive tape bandages, but prolonged, or repeated, application of 5% EMLA cream did not produce local skin reactions. Tests for delayed hypersensitivity reactions were negative. Plasma concentrations of lignocaine and prilocaine were low after a standard application.

1. The 'flooding dose' technique for measuring the rate of protein synthesis in tissues in vivo involves the injection of a large amount of unlabelled amino acid together with the tracer to minimize differences in isotopic enrichment of the free amino acid in plasma and tissue compartments. This approach has been investigated in human muscle by taking biopsies from postabsorptive male volunteers given [1-13C]leucine. 2. Intravenous injection of 4 g of unlabelled leucine resulted in a rapid rise in free leucine concentration of seven- to eleven-fold in plasma and five-fold in muscle. Values were still elevated by two-fold after 2 h. 3. Five minutes after injection of [1-13C]leucine (0.05 g/kg) the isotopic enrichment of plasma leucine was 82% that of the injected material, falling to 44% at 120 min. The enrichment of free leucine in sequential muscle biopsies was close to that in plasma and almost identical to that for plasma alpha-ketoisocaproate. 4. The rate of protein synthesis was determined from the increase in leucine enrichment in protein of muscle biopsies taken before and 90 min after injection of [1-13C]leucine (0.05 g/kg; 19 or 39 atom% excess) and the average plasma alpha-ketoisocaproate enrichment over this period (taken to represent muscle free leucine). The mean rate of muscle protein synthesis in 10 subjects was 1.95 (SEM 0.12) %/day. Rates of protein synthesis calculated from plasma leucine as precursor enrichment were only 5% lower than those calculated from plasma alpha-ketoisocaproate.(ABSTRACT TRUNCATED AT 250 WORDS)

Five patients were studied before and two to three days after major, uncomplicated abdominal operation. Muscle tissue was obtained by needle biopsy from m. quadriceps femoris after eight hours overnight fast. Plasma free amino acids were analyzed in simultaneously obtained samples. In the homogenized muscle samples the intracellular concentration of each amino acid (IC) was calculated by subtracting the free extracellular part from the total amount, assuming the plasma concentration to be equal to the concentration in the interstitial fluid. Their relationships have also been calculated (IC/EC gradient). The extra- and intracellular water distribution was estimated using a modified chloride method. In similarity to the findings in normal subjects the majority of the amino acids showed much higher concentration in intracellular water than in plasma. Preoperatively all amino acids examined in muscle biopsies were formed within normal limits. Postoperatively the total amount of free amino acids in plasma and muscle was decreased, and the amino acid profiles differed from those observed in normal subjects. In plasma, as compared with normal controls, the most significant changes were an increase in phenylalanine and tyrosine and a decrease in serine, proline, histidine and isoleucine. In muscle the greatest decrease occurred in the concentrations of glutamine, arginine and lysine followed by proline and glutamic acid. The increase in taurine, valine and phenylalanine were all highly significant and in serin, glycine, alanine and leucine significant, whereas tyrosine showed only a moderate rise. Compared with normal values there were marked increases in the gradient between intracellular and plasma concentrations which were highly significant for glycine and valine and significant for serine, alanine, isoleucine and leucine. The shift in the methionine gradient was somewhat less. We confirm that alterations in the muscle free amino acid pool are not reflected in the values found in plasma. Further work is required to explore the clinical significance of the observed variations in individual amino acids.