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Biomedical subjects

E Vinnars

Publications and source records attributed to E Vinnars.

At least 73 records · Page 4Linked to original sources
PubMed1986

The exchange of blood-borne amino acids in the leg during abdominal surgical trauma: effects of glucose infusion.

The exchange of plasma amino acids and glucose, lactate, glycerol and 3-hydroxybutyrate in the leg was studied in otherwise healthy patients undergoing elective cholecystectomy. Seven patients were given a constant intravenous infusion of glucose at a rate of 1.1 mmol/min throughout the study. Seven other patients who received normal saline only served as a control group. Measurement of leg blood flow and arterio-femoral venous differences of amino acids and other energy metabolites were made on four occasions: (I) before surgery, (II) 10 min after skin incision, (III) at the end of surgery, and (IV) 30 min after the end of anaesthesia. The release of amino acids from the leg was comparable in the two groups before and during the early part of surgery. At the end of surgery the release of several individual amino acids, as well as the total release of amino acids, from the leg was higher in the patients given glucose infusion compared with the control patients. The infusion of glucose prevented the intraoperative rise in arterial levels and uptake of 3-hydroxybutyrate in the leg. A high release of amino acids at the end of surgery was thus associated with low arterial levels of 3-hydroxybutyrate while the reverse pattern was seen in the control patients. These effects of glucose infusion were qualitatively different from those seen in uninjured postabsorptive man.

3-Hydroxybutyric Acid↗
PubMed1986

Glycine solution as an irrigating agent during transurethral prostatic resection. Glycine concentrations in blood plasma.

In 17 men undergoing transurethral resection of the prostate (TURP), an isosmotic solution of 2.2% glycine was used for irrigation. The plasma glycine concentration was determined before and immediately after TURP and 2, 6, 24 and 48 hours later. The serum concentrations of sodium, albumin and prostatic acid phosphatase protein (PAP) were used as indicators of fluid absorption. Calculation of the absorbed fluid volume was based on the plasma concentration of glycine, and the disappearance rate of glycine from plasma was estimated. The mean disappearance rate (T 1/2) was 85 min, which was midway between previously observed rates for sorbitol and mannitol. The observed plasma glycine increase after TURP correlated well with fall in serum sodium and rise in serum PAP, with the blood loss during and up to 15 min after TURP, and also with the weight of the resected tissue. The plasma glycine level, highest immediately after TURP, normalized 24-48 hours postoperatively. No signs of ammonia intoxication or marked serum urea increase were seen in these patients, although some had very high plasma glycine values after TURP (mean 10.2, maximum 23 mmol/l) as compared with the preoperative levels (mean 0.2 mmol/l). There was some increase of plasma serine (a normal metabolite of glycine) after TURP. The authors conclude that the irrigating fluid should have a minimal concentration of glycine, near to the level of haemolysis onset, to minimize the plasma dilution effects, including hyponatraemia, and the appearance of metabolites when the irrigating fluid is absorbed.

Acid Phosphatase↗
PubMed1986

The influence of abdominal surgery on the splanchnic exchange of amino acids.

The splanchnic exchange of amino acids was studied during and immediately after elective cholecystectomy in 10 patients given a constant infusion of glucose (1.1 mmol/min). Measurements of splanchnic blood flow and arteriohepatic venous differences of plasma amino acids, glucose, lactate and glycerol were made preoperatively, intraoperatively and twice in the immediate postoperative period. The arterial plasma concentration of most amino acids declined during and after surgery but the arterial concentration of alanine was highest in the postoperative period. The total splanchnic uptake of amino acids increased from 140.3 +/- 36.0 mumol/min preoperatively to 338.2 +/- 51.7 mumol/min postoperatively (p less than 0.05). Alanine and glutamine accounted for 65-70% of the total splanchnic uptake of amino acids throughout the investigation. The fractional extraction of methionine increased in the immediate postoperative period, while the fractional extraction of the remaining amino acids was stable. The splanchnic uptake of gluconeogenic substrates exceeded the splanchnic glucose release. The splanchnic uptake of amino acids had already increased intraoperatively and further increased postoperatively despite a net splanchnic glucose uptake in this period.

Abdomen↗
PubMed1985

The effect of pre-operative total parenteral nutrition on energy-rich phosphates, electrolytes and free amino acids in skeletal muscle of malnourished patients with gastric carcinoma.

The effect of two weeks of total parenteral nutrition (TPN) on energy-rich phosphates, muscle water, electrolytes and free amino acids in skeletal muscle were determined in ten malnourished patients with gastric carcinoma. The total adenine nucleotide pool, phosphocreatine, creatine and glycogen were decreased before TPN, and only glycogen returned to normal after TPN compared with controls. Total muscle water and the intramuscular concentrations of sodium and chloride were initially increased and were not influenced by TPN. The total non-essential amino acids in muscle were decreased by 9 per cent, mainly due to a 15 per cent decrease in glutamine. The concentrations of free amino acids in muscle were not affected by two weeks of TPN. This study demonstrates disturbances in energy, water and amino acid metabolism in skeletal muscle of malnourished patients with gastric carcinoma, and that two weeks of TPN could not normalize these changes, except in the case of glycogen. The reason for this might be enzyme abnormalities due to adaptation to energy or protein deficit. A longer period of refeeding might therefore be necessary to improve peripheral metabolism in these patients.

Aged↗
PubMed1985

Size distribution of ribosomes in biopsy specimens of human skeletal muscle during starvation.

The changes in the poly- and monoribosome distribution and in the total ribosome concentration in muscle during short term starvation were investigated. Transcutaneous muscle biopsies of 50 mg wet wt were taken from healthy human subjects, nonstarved and after one, two, and three days of total starvation. The percentage amount of polyribosomes was significantly lower (P less than 0.02) on days 2 and 3 of starvation than on day 0 (nonstarved). No significant sex-dependent differences were observed between the group of five females and six males. Ribosome concentration per g wet wt of muscle tissue was significantly lower on day 3 than on each preceding day (P less than 0.05). The reproducibility of the polyribosome analyses, together with the changes observed, suggest a future application of this method for evaluation of the effects of nutritional support in patients with posttraumatic and septic conditions.

Acetoacetates↗
PubMed1985

The diurnal pattern of protein synthesis in human skeletal muscle.

The diurnal pattern of protein synthesis in skeletal muscle was studied in relation to the serum concentrations of glucose, insulin and cortisol. Twelve healthy volunteers were given an ordinary hospital diet at 4-hourly intervals. The concentration of insulin showed peaks in response to food intake, and that of cortisol decreased over the day. Muscle biopsies were taken 30 min before the first food intake and 1.5 or 3.5 h after a meal. Irrespective of the time intervals after food intake, the total ribosome concentration, percentage amount of polyribosomes and polyribosome concentrations remained unaltered, indicating that there were no alterations in the capacity for protein synthesis accompanying the feeding schedule. The results suggest that a muscle sample taken in the morning after an overnight fast is representative of the protein synthesis during the day as assessed by the ribosome concentration and the size distribution of ribosomes.

Journal Article↗
PubMed1985

The effect of stress hormones on the interorgan flux of amino acids and on the concentration of free amino acids in skeletal muscle.

Plasma concentrations of free amino acids have previously been found to decrease posttraumatically and this decrease can be reproduced by infusion of stress hormones. The mechanisms underlying this effect has not been investigated and therefore 14 healthy subjects were studied by infusing adrenaline alone or a combination of adrenaline, glucagon, and cortisol, in dosages giving pathophysiological plasma concentrations of the hormones. The influence on the interorgan fluxes of free amino acids and on the concentrations of free amino acids in skeletal muscle were determined. During hormone infusion splanchnic oxygen consumption doubled, indicating an increase in metabolic activity. There was a significant decrease in the arterial plasma level of all amino acids except alanine. Significant increases in alanine flux was noted, the release from one leg doubled and the splanchnic uptake increased by 60%. After only 1 h all essential amino acids showed a significantly decreased concentration in muscle while the level of alanine was increased. There were no differences between the two hormone groups. The results indicate that stress hormones can initiate an increased formation of alanine in skeletal muscle and an increase in alanine transport from the periphery to the splanchnic area.

Journal Article↗
PubMed1985

Nitrogen sparing effect of Ornicetil in the immediate postoperative state clinical biochemistry and nitrogen balance.

The salt complex of alpha-ketoglutarate and ornithine, L(+)ornithine alpha-ketoglutarate - ORNICETIL (OR) - is able to bind six amino groups per molecule without enzymatic intervention. The present study was undertaken to determine whether intravenous administration of OR together with total parenteral nutrition (TPN) has a beneficial effect on nitrogen utilization in the immediate postoperative phase. Thirteen patients were investigated after major abdominal operations (resection of colon or rectum). All patients received TPN for 5 days postoperatively. Energy (165 kJ/kg BW) was given as fat (Intralipid 20%) and carbohydrate (Glucose 20%). Seven patients (controls) received 0.15 g amino acid (AA)-N/kg BW (Vamin). Six patients had an isonitrogenous regimen but with 2.5 g AA-N being replaced by Ornicetil (OR group). The excretion of urea, creatinine, ammonia, 3-methyl-histidine (3-MeHis) and total-N was determined throughout the study and the daily nitrogen balance was calculated. Blood samples were drawn serially before and after surgery for routine clinical biochemistry. The day-to-day nitrogen balance was significantly better when OR was given. Urea excretion was significantly reduced, and the urinary ammonia losses in the OR group were one third of those in the control group. In the control group 3-MeHis correlated negatively with the nitrogen balance. The regression line obtained, y = 265 - 21.6 x (p < 001), and the calculated correlation coefficient, r = 0.87 (p < 0.001), were highly significant. In contrast, no correlation could be demonstrated between 3-MeHis output and nitrogen balance in the OR group (r = 0.18, N.S.). The results indicate better postoperative nitrogen economy in the OR group than in the control group. Stimulation of insulin and growth hormone secretion may be contributing factors in the better nitrogen utilization. The increased ammonia excretion postoperatively in the control group was completely abolished when OR was given simultaneously with decreased urea formation, suggesting a product inhibition of arginase in the liver cytosol and also indicating that amino groups generated by the enhanced gluconeogenesis were trapped by OR owing to stimulated transamination in peripheral muscle tissues. The significant negative correlation between 3-MeHis excretion and nitrogen balance in the control group strongly indicates a correlation between net protein catabolism and increased postoperative muscle protein breakdown. In contrast, the total absence of correlation between nitrogen balance and 3-MeHis excretion in the OR group suggests a diminished (or zero) net muscle protein breakdown.

Journal Article↗
PubMed1985

Dermal effects of compositions based on the eutectic mixture of lignocaine and prilocaine (EMLA). Studies in volunteers.

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.

Administration, Topical↗
PubMed1984

Influence of alaproclate on antipyrine metabolite formation in man.

Alaproclate, a selective serotonin reuptake inhibitor, presently undergoing clinical trial for the treatment of major depressive disorders, has been shown to inhibit hexobarbital metabolism in mice. In the present study the influence of oral alaproclate on the total plasma clearance of antipyrine and on the formation of its metabolites was investigated in 10 healthy volunteers. The peak level of alaproclate was reached after about 1.5 h, and after a distribution phase, its plasma elimination half-life was between 3.0 and 3.5 h. Antipyrine tests were performed before treatment, during the first four doses and after the seventh dose of alaproclate 200 mg/day. During treatment, total plasma antipyrine clearance and the clearance for production of all antipyrine metabolites were reduced by 30%, indicating non-selective inhibition of oxidative drug-metabolizing enzyme activity in man by alaproclate. After the last dose of alaproclate, antipyrine plasma clearance and the clearance to its metabolites returned to control values. In order to allow more detailed evaluation of the results, the time course of the clearances for production of metabolites was investigated. This revealed that the extent of inhibition of metabolite formation by alaproclate was dependent on the plasma alaproclate level, indicating a rapidly reversible inhibition.

Adult↗
PubMed1984

The effect of severe trauma on muscle energy metabolism in man.

Muscle energy metabolism after severe trauma was studied in four nutritionally isocaloric groups of patients, receiving different amounts of glucose, fat and nitrogen. Muscle biopsy was performed 2, 4, 8 and 30 days after trauma. The pattern of energy metabolites was similar in all groups. Adenosine triphosphate was decreased on day 8, with further fall on day 30. Phosphoryl-creatine was reduced from day 2 onwards. Concomitant creatine increase gave a constant total creatine pool up to day 8 post-trauma. Lactate was increased and glycogen moderately decreased. The single exception to the pattern was greater increment of lactate and maintenance of glycogen levels in the specimens from groups with high glucose intake. The reduction in high-energy phosphates could have resulted from impaired substrate utilization or rapid degradation of tissue energy stores. The glucose and the lipid system were equally effective in supporting the cellular energy status after severe trauma.

Adenine Nucleotides↗
PubMed1983

Metabolic effects of four intravenous nutritional regimens after elective surgery. I. Clinical data and biochemistry.

Biochemical variables have been determined in 28 patients before and after resection of carcinoma of colon or rectum. A synthetic oral diet was given for four days before operation, (0.1 gN.kg/day and 165 kJ.kg/day) and four isocaloric intravenous regimens with different amounts and proportions of amino acids were given for six days after operation. During the preoperative diet the serum urea, glucose, urate, inorganic phosphate and cholesterol concentration decreased while those of triglyceride, iron and alanine amino-transferase increased. After operation the serum triglyceride, protein, albumin, iron, TIBC and urate concentrations decreased. The serum calcium fell in all groups receiving amino acids after operation while magnesium increased in all groups except the one receiving the highest amount of amino acids. The urea concentration decreased when no amino acids were given but increased when amino acids were administered whereas the reverse situation occurred with cholesterol. The highest increase in glucose level was observed when the highest amount of amino acids were given.

Journal Article↗
PubMed1983

Metabolic effects of four intravenous nutritional regimens in patients undergoing elective surgery II.--Muscle amino acids and energy-rich phosphates.

Muscle amino acids and energy-rich phosphates have been determined in 28 patients before and after resection of a carcinoma of colon or rectum. Before operation the patients received a synthetic diet (Vivasorb for four days and postoperatively four different intravenous regimens with different amounts and proportions of amino acids were given for six days, the energy intake being the same for all groups. When compared with age-matched healthy controls the patients showed only slight increases in phenylalanine and isoleucine concentration in muscle and plasma with elevated plasma glutamate during the four days prior to the operation. Vivasorb treatment increased the concentration of alanine, glycine and methionine in both muscle and plasma while increases of threonine and histidine were seen only in muscle. Decreased concentrations of valine were found in muscle and plasma, while lysine and leucine decreased only in plasma. As an effect of operation, but independent of the nutritional regimen, muscle asparagine increased and muscle glutamine and glutamate decreased in all groups. The unique pattern of amino acid changes in postoperative trauma was confirmed in the present investigation but few differences in amino acid concentrations could be related to the various nutritional intakes. Alterations in the individual amino acid concentrations were not influenced by the intake of amino acids and seemed to have little relationship to the composition of any solution infused. Prior to operation there were low levels of ATP in muscle possibly due to immobilisation and chronic semistarvation but no changes in the energy rich phosphates could be attributed to trauma or nutrition. The content of muscle glycogen increased as a result of the Vivasorb supply indicating that the preoperative carbohydrate administration promotes muscle glycogen synthesis and postoperatively muscle glycogen was reduced significantly indicating enhanced glycogenolysis in the postoperative state. This finding emphasizes the importance of providing the patients with ample amount of glucose before and after surgery.

Journal Article↗
PubMed1982

Metabolic studies in severe burns. Clinical features, routine biochemical analyses, nitrogen balance and metabolic rate.

The effects of two isocaloric regimens for parenteral nutrition were compared on days 2 to 8 after severe burns in 16 patients. Energy expenditure, plasma catecholamines, biochemical variables and N-balance were measured. The 8 patients in group I, with mean burn size 55/25%, received fat and glucose, while the 8 in group II, mean burn size 60/40%, were given 24 g amino acid nitrogen daily in addition to the fat and glucose. The mean metabolic rate on days 2-8 after burning was 70 +/- 7 and 69 +/- 5 kcal/m2/h in groups I and II, respectively. The mean values for plasma noradrenaline in the same period were 8.35 +/- 0.89 and 7.9 +/- 0.77 nmol/l. The biochemical changes showed a pattern typical of burns. There were no intergroup differences except for urea, which was significantly higher in the group (II) receiving amino acids. The cumulative N-balance was markedly less negative 8 days after trauma (-24 g N +/- 8 g) in group II than in group I (-100 g N +/- 10 g). These results indicate that a high nitrogen intake, together with adequate energy supply, improves the N-balance significantly in the early post-burn period. The high-energy supply from fat and glucose did not seem to cause the patients additional stress.

Adolescent↗
PubMed1981

Influence of injury and nutrition on muscle water electrolytes: effect of elective operation.

Injury is followed by a sequence of metabolic alterations which include fluid and sodium retention. This study used the percutaneous biopsy technique to analyze changes in muscle composition in regions nonadjacent to the area of surgical injury. The effect of nutritional intake on the changes observed in emphasized. Twenty-eight patients undergoing colectomy and 22 patients undergoing total hip replacement were studied. The patients undergoing colectomy resections received total parenteral nutrition with varying nitrogen intake. The patients undergoing hip replacement received either a) 5% dextrose solutions, b) 3.5% amino acid solutions, or c) both. Muscle biopsy procedures were performed preoperatively and postoperatively (day three on the colectomy patients) (day four on the hip replacement patients). The role of inactivity was assessed in eight healthy subjects maintained on strict bedrest for four days. Four subjects received a regular diet, while four received 5% dextrose solution for four days. The tissue samples were analyzed for water, sodium, chloride, potassium, magnesium, and in selected cases glycogen. No significant effects of bedrest with either a regular diet or semistarvation were observed. Surgical injury caused an increase in muscle water, sodium, and chloride while there was a slight reduction in potassium in all groups, with the exception of those colectomy patients who received no amino acids after operation. There was no effect of varying the level of nitrogen intake in the colectomy patients, nor was there an effect of different hypocaloric infusions, in the hip replacement patients. The colectomy patients on admission to the hospital, showed some signs of prior nutritional depletion. After receiving four days of preoperative nutrition, there was a decrease in extracellular water, in sodium and chloride towards normal values. Following injury, there was an increase in muscle water, sodium and chloride, while potassium decreased slightly. In the postoperative period there were only minimal effects of nutritional intake on the observed changes.

Bed Rest↗
PubMed1981

Hepatic gluconeogenesis during halothane anaesthesia in man.

It is known that hepatic gluconeogenesis from lactate and aminoacids is inhibited by halothane in in vitro studies on isolated, perfused livers. In the present work, the effect of halothane anaesthesia on hepatic gluconeogenesis was studied in three volunteers during a constant amino-acid infusion and compared with three control subjects who did not receive any halothane during the amino-acid infusion. Prior to the investigation, all the subjects were on a carbohydrate-poor diet in order to deplete hepatic glucogen stores. During the investigation, hepatic gluconeogenesis was stimulated by a constant amino-acid infusion which caused a slight rise in total hepatic blood flow (THBF), a marked increase in splanchnic oxygen consumption and oxygen extraction, elevation in blood glucose and urea levels and in splanchnic glucose and urea releases. Halothane anaesthesia administered during continued amino-acid infusion caused a reduction in THBF to sub-control values, while the increased oxygen consumption was only slightly reduced, thereby further increasing splanchnic oxygen extraction. Blood glucose and urea levels of the anaesthetized subjects were consistent with those of the control subjects. Splanchnic release of glucose was reduced almost to control values during halothane. However, the release of urea was only slightly reduced. It is concluded that the stimulating effect on hepatic gluconeogenesis caused by the amino-acid infusion was inhibited during halothane anaesthesia, while metabolization of the amino-acids, other than through gluconeogenesis, proceeded without any major changes.

Adult↗