Biomedical subjects
Publications and source records attributed to E Vinnars.
A 200-mg amount of bacampicillin showed a significantly higher relative extent of bioavailability than did a 250-mg amount of talampicillin, possibly due to their different stability in the digestive juices.
The effect of three different isocaloric parenteral nutritional regimes has been investigated in the early postoperative period in 19 patients with severe multiple injuries. Clinical course, biochemical analyses and nitrogen balance were monitored. The first group received glucose and insulin (n = 7), the second group fat and glucose (n = 6) and the third group fat, glucose and 24 g aminoacid-nitrogen (n = 6). The clinical course was similar in the three groups and all patients survived. The biochemical changes showed a typical pattern for trauma and there were no differences between the groups except for urea, which was significantly higher in the group receiving amino acids. The cumulative nitrogen balance was markedly less negative one week after trauma (-45 g N +/- 8) in the group given amino acids, glucose and fat compared to those given isocaloric amounts of glucose (-84 g N +/- 12) or glucose and fat (-95 g N +/- 10). This improvement in nitrogen balance was probably mainly due to an increase in protein synthesis.
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The effect of different intravenous nutritional regimens on nitrogen balance and 3-methylhistidine (3-MeHIS) excretion were studied during a 6-day period following major elective surgery in 28 patients. All patients were kept on a synthetic diet 4 days prior to surgery and were given 0.1 g amino acid N and 120 kJ/kg . day. Postoperatively, all patients received parenteral nutrition with approximately 170 kJ/kg . day. Postoperatively, all patients received parenteral nutrition with approximately 170 kJ/kg . day. Three groups of patients were given varying amounts and proportions of amino acids while in one group no amino acids were administered. Preoperatively, urinary 3-MeHIS excretion (determined by a newly developed automatic analyzer) was 240.3 mumole/day +/- 9.2, nitrogen balance was -1.8 g N +/- 0.19. Postoperatively, nitrogen balance was less negative when amino acids were given. The degree of improvement depended on the amount, but not on the composition of nitrogen administered. In all four groups, 3-MeHIS outputs were elevated when compared with preoperative excretion. The 3-MeHIS excretion (mumole/day) was increased more in patients on high amino acid supply than in patients with low or no nitrogen supply. In each of the groups the 3-MeHIS excretion was negatively correlated to the nitrogen balance. Regression analyses suggest that postoperative muscle protein breakdown occurs in relation to the body protein loss. Amino acid administration seems not to decrease muscle protein breakdown, but rather, appears to stimulate protein synthesis, resulting in less net protein loss. The mean rate of muscle protein breakdown in the postoperative state was estimated to be 80 g/day, assuming 4.2 mumole 3-MeHIS per g mixed human muscle protein. This exceeded the mean preoperative breakdown by about 23 g muscle protein per day. This increase might be due to the metabolic response to the trauma and also in part to tissue damage by the surgical procedure.
The effects of different intravenous nutritional regimens on a number of biochemical indices of nutritional status were studied during the 8-day period following severe trauma. The inclusion of large amounts of amino acids (high nitrogen (N) was shown to greatly improve N balance over an isocaloric regimen containing no amino acids (O g N). The concentration of serum albumin, transferrin, prealbumin, and retinol-binding protein all fell during the study period in both patient groups, whereas the serum concentrations of acute phase reactants and of ribonuclease increased in the two groups. The sum of plasma levels of branched-chain amino acids and the essential amino acids was increased to a greater extent in the high N group. These amino acid totals and the ratio of glycine/valine showed a significant correlation with N balance in this group. Despite the marked difference in N balance, 3-methylhistidine excretion was increased but equal in the two nutritional groups, suggesting an increased rate of muscle protein breakdown in both groups, which appears not to be influenced by amino acid nutrition. It is concluded that N balance can be significantly improved in the immediate posttrauma period by provision of amino acids together with energy substrates. None of the biochemical variables measured, with the exception of plasma levels of essential amino acids, reflected these marked differences in N balance.
This study examines the effect of three different hypocaloric diets on the patterns of muscle and plasma amino acids in patients undergoing total hip replacement. Group I (seven patients) received 90 g/day of glucose, Group II (seven patients) received 70 g/day of amino acids, Group III (eight patients) received both 90 g of glucose and 70 grams of amino acids per day. Utilizing the percutaneous biopsy technique of Bergström, free amino acid patterns in muscle and plasma were analyzed pre- and postoperatively (day 4). The postoperative pattern of amino acids was characterized by elevated levels in muscle and plasma of the branched chain amino acids, phenylalanine, tyrosine and methionine. There was a marked decrease in muscle glutamine and smaller decreases in the basic amino acids in both muscle and plasma. Muscle:plasma concentration ratios increased for the neutral amino acids, decreased for glutamine and the basic amino acids and were unchanged for the acidic amino acids. The patterns seen after hip replacement are almost identical to those seen after colectomy or accidental injury. There was little effect of diet on amino acid concentrations in muscle. In plasma, concentrations of leucine, isoleucine, valine and proline were higher in Group II in the absence of glucose intake, than in the other groups. Lysine was lower in Group I with no amino acid intake than in the other groups. Thus, there is a unique amino acid pattern associated with operative trauma which is relatively unaffected by hypocaloric, intravenous nutrition.
A new apparatus, which uses a fuel cell for measuring O2 concentration and calculates O2 consumption (VO2), has been developed for use on the Servo Ventilator. Together with an IR CO2 Analyzer, this equipment also provides CO2 production, end-tidal CO2 concentration, and the respiratory quotient.l The accuracy of this equipment was evaluated by comparison with results from two standard methods: the Scholander technique in combination with a dry gas meter, and mass spectrometry combined with a wet gas meter. The results show that the differences between the VO2 calculated from this equipment and two other standard methods are less than 5%. Thus, the accuracy of the new equipment seems reliable enough to make it a valuable tool in clinical use.
1. Free amino acids were determined in the plasma and in the muscle tissue of 14 patients with chronic uraemia; eight were not on dialysis and six were having regular peritoneal dialysis. The concentration of each amino acid in muscle water was calculated with the chloride method. 2. In both groups of patients there were low intracellular concentrations of threonine, valine, tyrosine and carnosine, and high glycine/valine and phenylalanine/tyrosine ratios. Both groups of patients had increased amounts of 1- and 3-methyl-histidine in plasma and in muscle water. 3. The non-dialysed patients had low intracellular concentrations of lysine, and the dialysed patients had high intracellular concentrations of lysine, isoleucine, leucine and of some of the non-essential amino acids. 4. After peritoneal dialysis for 22 h, the plasma concentration of several amino acids decreased but the intracellular concentrations of most amino acids did not change significantly. 5. Intravenous administration of essential amino acids and histidine during the last 4 h of dialysis increased in muscle the total free amino acids, the ratio of essential to non-essential amino acids and the valine and phenylalanine concentrations. 6. The results demonstrated that the plasma and muscle concentrations of several amino acids are grossly abnormal in chronic uraemia. Non-dialysed and dialysed patients exhibit important differences, especially in the intracellular amino acid patterns. Infusion of essential amino acids may result in enhancement of protein synthesis.
The amino acid pattern following total hip replacement is characterized by increases in muscle of the branched chain amino acids (leucine, isoleucine and valine), the aromatics (phenylalanine and tyrosine) as well as methionine. The nonessential amino acids in muscle tend to decline, glutamine having the most marked change. Plasma levels of the essential amino acids increase while the nonessentials tend to decrease. This pattern differs from that observed in other catabolic states (uremia, starvation, untreated diabetes) and is significantly different from the effects of inactivity and starvation combined. This suggests that injury can be characterized by a unique pattern of muscle and plasma amino acids.
1. Two women with severe hypokalaemic alkalosis were investigated by means of muscle biopsy before and at the end of 2 and 3 weeks respectively of intense therapy with potassium chloride. 2. The muscle biopsy material was analysed for water, electrolytes, adenine nucleotides, phosphocreatine, free creatine, pyruvate, lactate, glycogen and free amino acids. The extra- and intra-cellular distribution of water, electrolytes and amino acids was calculated by the chloride method. 3. Both patients showed a marked loss of intracellular potassium and an increase in intracellular sodium concentration. The muscle magnesium content was also slightly decreased. After repletion with potassium chloride, muscle sodium and potassium became normal. 4. The contents of creatine phosphate, ATP, ADP, AMP, lactate and pyruvate were within normal limits, but the phosphocreatine/total creatine ratio was reduced. After repletion, a small change in the apparent creatine-phosphokinase equilibrium had occurred, suggesting a minor increase in intracellular pH. 5. The concentrations of the basic amino acids, lysine, arginine and ornithine were increased far above normal. The intracellular accumulation of arginine was much higher than the increase in lysine concentration and histidine concentration was normal. This differs from findings in potassium-depleted rats, where the intracellular lysine concentration is much higher than arginine concentration and histidine is high as well. After potassium repletion the intracellular concentration of ornithine, lysine and arginine became normal in one case and decreased considerable in the other. An increased intracellular concentration of glutamate and glutamine was also observed after potassium repletion.
Lactate production from the liver during fructose infusion was decreased when an amino acid infusion was given simultaneously. The most pronounced decrease was observed when the amino acid infusion was started before the simultaneous administration of fructose and amino acids. The explanation of the phenomenon is thought to be a stimulation of gluconeogenesis by amino acids.
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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.
Nitrogen balance studies in chronic severe uremia have shown that it is possible to convert the negative nitrogen balance on a protein-poor diet to a positive one when the diet is supplemented with the essential amino acids intravenously or orally. It has been possible to make the diet variable and good tasting. This is a great advance as the patients can remain on the diet for a long time. 15N-studies have shown that this nitrogen balance represents true protein synthesis. These studies have also shown that histidine may be an essential amino acid in chronic severe uremia and further improves the nitrogen balance. During long-term treatment with the diet supplemented with essential amino acids including histidine, no signs of progressive neuropathy, bleeding or muscle wasting have been observed. We think that this diet and amino acid regimen is a feasible way to keep chronic severe uremic patients in fairly good general condition and nutritive state until they can have a renal transplantation or a place in a home-dialysis program.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.