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Biomedical subjects

E Vinnars

Publications and source records attributed to E Vinnars.

At least 55 records · Page 3Linked to original sources
PubMed1989

Stress hormones given to healthy volunteers alter the concentration and configuration of ribosomes in skeletal muscle, reflecting changes in protein synthesis.

1. The influence of elevated concentrations of stress hormones on the concentration of ribosomes and the relative proportion of polyribosomes, reflecting protein synthesis in vivo, in human skeletal muscle was investigated. Healthy volunteers were given a 6 h infusion of adrenaline (n = 8), cortisol (n = 8), a triple-hormone combination of adrenaline, cortisol and glucagon (n = 8), or saline (n = 8). 2. The total ribosome concentration declined by 30.4 +/- 7.2% in the triple-hormone group (P less than 0.01), by 26.9 +/- 8.6% in the cortisol group (P less than 0.05) and by 24.8 +/- 11.2% in the adrenaline group (P less than 0.05). The proportion of polyribosomes to total ribosomes decreased by 8.5 +/- 2.2% in the triple-hormone group (P less than 0.05). 3. During hormone infusion the serum glucose levels were enhanced. The insulin concentrations in serum were elevated in the adrenaline group and the triple-hormone group, but not in the cortisol group. Serum insulin decreased in the control group. 4. The results indicate an effect of the combined stress hormone infusion on the total ribosome concentration as well as on the relative abundance of polyribosomes. The single hormones influenced the total ribosome concentration only. The results suggest a critical role for stress hormones in producing the decline in muscle protein synthesis seen after trauma.

Adult↗
PubMed1989

Addition of glutamine to total parenteral nutrition after elective abdominal surgery spares free glutamine in muscle, counteracts the fall in muscle protein synthesis, and improves nitrogen balance.

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.

Cholecystectomy↗
PubMed1988

Availability of amino acids supplied intravenously in healthy man as synthetic dipeptides: kinetic evaluation of L-alanyl-L-glutamine and glycyl-L-tyrosine.

1. For the first time utilization of intravenously administered L-alanyl-L-glutamine and glycyl-L-tyrosine was investigated by means of their kinetic behaviour after bolus injection in 10 and 11 apparently healthy male subjects (age 26.6 +/- 5.7 years), respectively. 2. The injection of the synthetic dipeptides was not accompanied by any side effects or complaints. 3. The synthetic dipeptides L-alanyl-L-glutamine and glycyl-L-tyrosine were rapidly cleared from plasma. By applying a monoexponential model the elimination half-lives were found to have very similar values (3.8 +/- 0.5 and 3.4 +/- 0.3 min) whether alanine or glycine was occupying the N-terminal position. The estimated volume of distribution was approximately that of the extracellular space. 4. Peptide disappearance was accompanied by a prompt equimolar increase in the concentrations of the constituent amino acids alanine and glutamine as well as glycine and tyrosine. 5. The study provides firm evidence that L-alanyl-L-glutamine and glycyl-L-tyrosine are rapidly (quantitatively) hydrolysed. The results of this study may indicate a safe and efficient parenteral use of the investigated peptides as sources of free glutamine and free tyrosine.

Adult↗
PubMed1988

Protein synthesis assessed by ribosome analysis in human papillary muscle in relation to oxidative capacity: a comparison with skeletal muscle.

Protein synthesis as assessed by the concentration and size distribution of ribosomes was determined together with citrate synthase activity in papillary muscles obtained at open heart surgery from patients with mitral valve disease. The results were compared with corresponding data from the quadriceps femoris muscle of patients undergoing cholecystectomy. Citrate synthase activity was six times higher in papillary muscle than in skeletal muscle. The total ribosome concentration per mg DNA was similar in the two types of muscle. Compared with skeletal muscle, in papillary muscle polyribosomes constituted a higher proportion of the ribosomes (p less than 0.001), and there was a tendency towards larger polyribosome aggregates. It is proposed that the high concentration of polyribosomes in papillary muscle is related to the high oxidative capacity of that tissue.

Citrate (si)-Synthase↗
PubMed1988

Enzymatic capacity and protein synthesis in human muscle postoperatively.

The glycolytic and aerobic oxidative capacity in skeletal muscle was investigated to reveal if the decrease seen in muscle protein synthesis is accompanied by a fall in the enzymatic capacity to oxidize substrates. Six patients undergoing elective abdominal surgery were investigated by percutaneous muscle biopsies taken before surgery and on the first and third postoperative days. Protein synthesis as assessed by the polyribosome concentration was 40% lower on the third day postoperatively than before surgery (p less than 0.01). The glycolytic and oxidative capacity was evaluated by determining the activity of eight key enzymes in the intracellular oxidative metabolism, namely total creatine kinase (CK), the isozymes CK-MB and mitochondrial CK, lactate dehydrogenase, citrate synthase, aspartate aminotransferase, and phosphofructokinase, and also the concentration of myoglobin. None of these parameters were affected in the immediate postoperative period independently of the provision of nutritional support. It was concluded that the decrease in protein synthesis is not accompanied by a concomitant decline in the enzymatic oxidative capacity in skeletal muscle in the period immediately following elective surgery.

Adult↗
PubMed1987

Protein synthesis in skeletal muscle of rats following starvation and refeeding.

Determination of protein synthesis in individual tissues is important to understand the changes in protein metabolism during catabolic states. Three methods based on different underlying assumptions were compared in assessing muscle protein synthesis during nutritional manipulation. Rats were nonstarved, starved for 1 or 3 days, or refed for 2 days after 3 days of starvation. The extensor digitorum longus (EDL) muscles from the two hindlegs were used for analysis. In one EDL muscle the concentration and size distribution of ribosomes as well as the incorporation of [14C]leucine into protein in a cell-free system were determined. The other EDL muscle was incubated as such and the incorporation of [14C]phenylalanine into protein was measured. The total ribosome concentration per milligram of DNA decreased to 65% on the third day of starvation and remained low after refeeding. The amount of polyribosomes in the percentage of total ribosomes fell to 90% on the first day of starvation, regained the initial level on the third day, and reached 110% upon refeeding. During refeeding amino acid incorporation into protein in a cell-free system decreased to 40% and that in intact muscle to 64% of the prestarvation level. Upon refeeding, the activity increased to or above the original values. The use of several different techniques in parallel to assess protein synthesis in skeletal muscle is recommended since it gives information about the factors involved in regulation of the translational process in intact mammalian tissues.

Animals↗
PubMed1987

Ornithine-alpha-ketoglutarate improves skeletal muscle protein synthesis as assessed by ribosome analysis and nitrogen use after surgery.

Total parenteral nutrition (TPN) was given for 3 days after elective abdominal surgery. The control group (N = 9) received TPN only and one group of patients (N = 6) received TPN supplemented with ornithine-alpha-ketoglutarate (0.35 g/kg bw/day). Protein synthesis in skeletal muscle was assessed from the total ribosome concentration and the percentage of polyribosomes. In the control group the total concentration of ribosomes decreased after surgery by 23% (p less than 0.05) and the percentage of polyribosomes decreased by 21% (p less than 0.01), whereas in the ornithine-alpha-ketoglutarate group both variables remained unaffected. The cumulative urinary urea excretion was significantly larger in the control group than in the ornithine-alpha-ketoglutarate group (p less than 0.05). The calculated nitrogen balance was negative in the control group on each day of the study (p less than 0.05), but that of the ornithine-alpha-ketoglutarate group was not statistically different from zero. The results show that postoperative maintenance of muscle protein synthesis and a more effective nitrogen use was achieved by supplementing TPN with ornithine-alpha-ketoglutarate, 0.35 g/kg bw/day.

Cholecystectomy↗
PubMed1987

The influence of epidural analgesia on the splanchnic exchange of amino acids during upper abdominal surgery.

Splanchnic turnover of plasma amino acids was studied in 10 patients given thoracic epidural analgesia combined with general anaesthesia for elective cholecystectomy. Ten other patients given only general anaesthesia for cholecystectomy served as a control group. All patients received an infusion of glucose during the investigation. The total concentration of amino acids in arterial plasma did not change in the patients given epidural analgesia but decreased by approximately 15% in the non-epidural group. In both groups splanchnic uptake of amino acids increased during surgery and was found to be more than doubled in the early postoperative period. The addition of epidural analgesia to general anaesthesia did not modify the splanchnic uptake of amino acids during surgery and in the immediate (2 h) postoperative period.

Abdomen↗
PubMed1987

Plasma clearance of fat emulsion during continuous heparin infusion.

Intravenous fat tolerance was tested in two groups of patients given a continuous i.v. infusion of heparin for several days. One group of 11 patients with deep vein thrombosis (DVT) of the leg was given 25,000-35,000 IU heparin daily for 4-5 days. The other group comprised 10 patients who had central venous catheters (CVC) for total parenteral nutrition. These patients were given 20,000 IU heparin daily for 6 days as prophylaxis against CVC-related thrombosis. In the DVT group heparinization was associated with a 44% decrease in plasma fat removal capacity (P less than 0.05). This reduction persisted for 2 days after the discontinuation of heparin therapy. In the CVC group the plasma fat removal capacity decreased by 29% during heparinization (P greater than 0.05, NS). During heparinization activated partial thromboplastin time was more than three times the basal value in the DVT group but less than twice those in the CVC group. One week after the heparin therapy the serum triglyceride levels were higher in both groups compared with initial values (DVT group: 1.2 +/- 0.2 s.e. mean vs. 1.7 +/- 0.3 mmol/l; P less than 0.05. CVC group: 1.0 +/- 0.1 vs. 1.4 +/- 0.2 mmol/l; NS). The possibility that full-dose heparinization reduces plasma fat removal capacity and that this may be due to a partial depletion of lipoprotein lipase stores is discussed.

Aged↗
PubMed1987

Postoperative water and electrolyte changes in skeletal muscle: a clinical study with three different intravenous infusions.

Twenty-seven patients admitted for cholecystectomy were matched for age and sex in three groups for different perioperative fluid therapies over a period of 3 days. Group I was given an acetated half-isotone "balanced" saline solution with the addition of 2.5% glucose, Group II an acetated Ringer solution and Group III an isotonic glucose solution. Percutaneous muscle biopsies were performed before and on the third day after surgery for the determination of water content and the concentration of sodium, potassium, magnesium and chloride in skeletal muscle. The cumulative balance of sodium and potassium was measured daily during the study. In all three groups a significant increase in the total muscle water content was demonstrated. The concentration of sodium and chloride in skeletal muscle increased significantly in Groups II and III, whereas the concentration of potassium decreased in all groups. The cumulative sodium balance was positive in Groups I and II; the potassium balance was negative in all groups. In conclusion, the patients given the balanced saline solution showed the least change in water content and electrolyte concentrations in skeletal muscle.

Adult↗
PubMed1987

Plasma haemoglobin concentrations and other influx variables in blood in connection with transurethral resection of the prostate using distilled water as an irrigating fluid.

Eight patients undergoing transurethral resection of the prostate (TURP) using sterile distilled water as an irrigating fluid were studied. The concentrations of plasma haemoglobin, serum sodium, serum prostatic acid phosphatase protein (PAP) and plasma osmolality were determined as possible indicators of absorption of irrigating fluid. In 3 patients there was a marked increase in plasma haemoglobin immediately postoperatively with a maximum of 3.3 g haemoglobin/l plasma. In the remaining 5 patients the plasma haemoglobin level did not exceed 0.7 g/l immediately postoperatively. In all cases there was a fairly rapid return of the elevated plasma haemoglobin level to preoperative values. There was also a postoperative increase in the serum PAP level which was not correlated with the simultaneous increase in plasma haemoglobin concentration. There was no significant change in the sodium, potassium or albumin concentration in serum nor in plasma osmolality postoperatively. There was some decrease in the postoperative serum creatinine and uric acid levels. The preoperative serum creatinine concentration was within reference limits in 7 patients and borderline high in 1 patient. The haemoglobin binding plasma protein haptoglobin showed a slight non-significant increase immediately postoperatively and a significant decrease in concentration 2 hours postoperatively. The mean plasma haemoglobin concentration immediately postoperatively did not exceed the mean preoperative haemoglobin binding capacity of serum. The mean preoperative haemoglobin binding capacity was 1.2 g/l and the mean plasma haemoglobin level was 1.2 g/l immediately postoperatively. Two hours later the mean plasma haemoglobin level was 0.8 g/l. The mean serum haptoglobin concentration was 2.4 g/l preoperatively, 2.6 g/l immediately postoperatively and 2.0 g/l 2 hours later.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid Phosphatase↗
PubMed1987

Fatigue and muscle amino acids during surgical convalescence.

Muscle and plasma amino acids, subjective fatigue and body weight were studied in 16 patients before and 20 days after uncomplicated elective abdominal surgery. Fatigue increased from a mean (+/- SEM) preoperative level of 2.4 +/- 0.4 arbitrary units to 4.4 +/- 0.5 on postoperative day 20, while body weight fell from 67.3 +/- 2.5 to 64.7 +/- 2.9 kg (both differences p less than 0.001). Correlation was found between increase in fatigue and fall in body weight (r = 0.56, p less than 0.05). Plasma amino acids showed little change after surgery. In muscle, the nonessential amino group taurine, asparagine, glutamate and glycine increased and histidine and arginine decreased (both p less than 0.05) postoperatively. No correlation was found between postoperative fatigue and weight loss versus changes in muscle amino acids. Some of the well-defined immediate postoperative changes in muscle amino acids thus persisted into late, otherwise uncomplicated convalescence, but postoperative fatigue was related only to weight loss--not to changes in muscle or plasma amino acids.

Adolescent↗
PubMed1987

Influence of injury and nutrition on muscle water and electrolytes: effect of severe injury, burns and sepsis.

The changes in water and electrolyte metabolism associated with severe injury and sepsis are well recognized but changes in tissue content have seldom been available. This report combines the experience obtained from muscle biopsies of such patients performed in two centers; one located in Sweden and one in the U.S. Normal values for muscle water and electrolytes in each center are in close agreement. Needle biopsies of muscle were performed in 45 Swedish patients and 17 U.S. patients at intervals after injury or infection from the second to the thirtieth day. The patients' nutrition varied from brief periods of hypocaloric intake to prolonged high calorie parenteral nutrition with and without amino acids, as well as with and without fat. Prominent changes appeared during the first week and persisted up to 30 days regardless of the associated nutritional intake. These changes included an increased total muscle water, extracellular water, sodium and chloride and a decrease in muscle potassium and magnesium. This study demonstrates a simultaneous expansion of extracellular volume and a loss of intracellular components. This is in contrast to the experiences reported with less severe injury such as elective operation, where a more modest expansion of extracellular volume is seen and which is not associated with any loss of potassium or magnesium. The magnitude and persistence of these changes in muscle tissue deserve further study, both as to mechanism and implications for therapy.

Adult↗
PubMed1986

Polyribosome concentration in human skeletal muscle after starvation and parenteral or enteral refeeding.

Posttraumatic and septic states cause a loss of body proteins resulting in a negative nitrogen balance. The major part of the excreted nitrogen is derived from the proteins of skeletal muscle. The loss in proteins is due to a decrease in protein synthesis rather than an increase in protein degradation. Nutritional support may increase protein synthesis, and determination of its activity in skeletal muscle will give information on the utilization of nutrients in catabolic patients. The effect of nutritional support on healthy subjects was studied to achieve a background for future clinical studies. Male volunteers between 20 and 40 years old were refed parenterally or enterally after three days of starvation. Muscle biopsies (50 mg) were analyzed for the size distribution of ribosomes in a sucrose density gradient, and the ribosome concentration was determined per mg of DNA. Changes in the percentage content of polyribosomes preceded those of the total ribosome concentration. The total polyribosome concentration per gram wet weight of skeletal muscle decreased significantly during starvation. After one and two days of refeeding, a significant increase was observed, but the original level of the nonstarved subjects was not reached. The total ribosome concentration increased upon refeeding, but was not significantly different from that of the starved condition. The nitrogen balance was negative during starvation but attained equilibrium after two days of refeeding. Nutrition administered by the parenteral or enteral route were equally effective in restoring protein synthesis.

3-Hydroxybutyric Acid↗
PubMed1986

The influence of abdominal surgical trauma on the exchange of blood-borne amino acids in the human leg.

Associated with surgical trauma is an increased release of gluconeogenic substrates from the periphery. The present study was undertaken to investigate the peripheral exchange of blood and plasma amino acids as well as some other gluconeogenic substrates (lactate and glycerol) in connection with abdominal surgery. Measurements of leg blood flow and femoral arterio-venous substrate differences were made before, during and immediately after elective cholecystectomy. Blood and plasma concentrations of most amino acids except alanine decreased during and immediately after surgery. Simultaneously there was an increased release of several of the amino acids as well as lactate and glycerol from the leg. The total release of plasma amino acids from one leg in the immediate postoperative period was about 2.5 times as high as before surgery. The turnover rates of amino acids as well as the changes in turnover rates were comparable whether the calculations were made from plasma or whole blood concentrations. At the end of surgery there was a high peripheral uptake of 3-hydroxybutyrate concomitant with a low release of amino acids.

Journal Article↗