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Biomedical subjects

U Angerås

Publications and source records attributed to U Angerås.

At least 19 recordsLinked to original sources
PubMed1991

Reduced levels of mRNA for myofibrillar proteins in skeletal muscle from septic rats.

The influence of sepsis on transcription of myofibrillar proteins in skeletal muscle was studied in rats. Sepsis was induced by cecal ligation and puncture (CLP); control rats were sham-operated. Sixteen hours later, muscle levels of mRNA for myofibrillar proteins were determined by using cDNA probes specific for transcripts for alpha actin and myosin heavy chain. Sepsis resulted in a 2-6 fold decrease in alpha actin mRNA levels and an even more pronounced reduction in myosin heavy chain mRNA levels. Results suggest that sepsis-induced reduction of muscle protein synthesis is at least partly regulated at the transcriptional level.

Actins↗
PubMed1991

Influence of sepsis in rats on muscle protein turnover in vivo and in tissue incubated under different in vitro conditions.

We studied the influence of sepsis on muscle protein synthesis and degradation in vivo and in muscles, incubated flaccid or at resting length. Sepsis was induced in rats by cecal ligation and puncture (CLP). Control rats were sham-operated. A flooding dose of 14C-phenylalanine was used to determine muscle protein synthesis rate in vivo, and protein breakdown was calculated from the difference between protein synthesis and growth rates. Protein synthesis rate in vitro was assessed by determining incorporation of 14C-phenylalanine into protein in incubated extensor digitorum longus (EDL) and soleus (SOL) muscles. Total and myofibrillar protein breakdown rates were determined from release into incubation medium of tyrosine and 3-methylhistidine (3-MH), respectively. Muscle protein synthesis rate in vivo was reduced by 35%, similar to the reduction observed in muscles incubated flaccid or at resting length. The calculated protein breakdown rate in vivo was increased by 31% in septic rats. In incubated muscles, the increase in total protein breakdown (ie, tyrosine release) during sepsis was almost identical in muscles incubated flaccid or at resting length, ie, 83% to 88% in EDL and 47% to 49% in SOL. Myofibrillar protein degradation in vitro (ie, 3-MH release) was increased approximately 10-fold in EDL muscles incubated flaccid or at resting length, but was not significantly affected by sepsis in SOL. Results suggest that sepsis-induced changes in protein synthesis observed in muscles incubated either flaccid or at resting length reflect changes in vivo. Changes in protein breakdown were qualitatively similar in vivo and in vitro, but results in incubated muscles may overestimate the increase in muscle proteolysis caused by sepsis.

Adenosine Triphosphate↗
PubMed1991

Tissue metabolite levels in different types of skeletal muscle during sepsis.

The effect of sepsis on energy and metabolite levels in the white, fast-twitch extensor digitorum longus (EDL) and the red, slow-twitch soleus (SOL) muscles was studied in rats. Sepsis was induced by cecal ligation and puncture (CLP). Control rats were sham-operated. Sixteen hours later, metabolite levels in muscle tissue were determined. Adenosine triphosphate (ATP) levels and energy charge were reduced during sepsis in SOL, but were unchanged in EDL muscles. In contrast, phosphocreatine (PCr) concentration was reduced during sepsis in EDL, but not in SOL. Tissue glycogen levels were reduced and lactate concentrations were increased in both muscles during sepsis. Results suggest that sepsis affects energy metabolism differently in different types of skeletal muscle. Tissue lactate accumulation may be consistent with muscle hypoperfusion following CLP, although other mechanisms may also be involved.

Adenosine Triphosphate↗
PubMed1991

Effect of the glucocorticoid receptor antagonist RU 38486 on muscle protein breakdown in sepsis.

The role of glucocorticoids in muscle catabolism during sepsis was tested with the glucocorticoid receptor antagonist RU 38486. Sepsis was induced in male Sprague-Dawley rats (40 to 60 gm) by cecal ligation and puncture (CLP). Other animals underwent sham operation. Two hours before CLP or sham operation, rats received RU 38486 (5 mg/kg) or a corresponding volume of vehicle by gavage. Sixteen hours after CLP or sham operation, protein synthesis rate was determined by measuring incorporation of 14C-phenylalanine into protein in incubated extensor digitorum longus muscles. Total and myofibrillar protein breakdown rates were determined by measuring net release of tyrosine and 3-methylhistidine, respectively. The protein synthesis rate was approximately 30% lower in rats with sepsis than in sham operated rats and was not affected by treatment with RU 38486. The total protein breakdown rate was increased by approximately 70% and myofibrillar protein degradation was increased more than fivefold in muscle from rats with sepsis. Treatment with RU 38486 resulted in a 28% reduction of total and a 44% reduction of myofibrillar protein breakdown in rats with sepsis but did not affect proteolysis in muscle from sham-operated animals. The results support a role of glucocorticoids in accelerated muscle proteolysis during sepsis. It is not clear whether glucocorticoids are the only required mediator or they interact with other substances to induce muscle protein breakdown during sepsis.

Animals↗
PubMed1990

Regulation of total and myofibrillar protein breakdown in rat extensor digitorum longus and soleus muscle incubated flaccid or at resting length.

The present study characterized total and myofibrillar protein breakdown rates in a muscle preparation frequently used in vitro, i.e. incubated extensor digitorum longus (EDL) and soleus (SOL) muscles of young rats. Total and myofibrillar protein breakdown rates were assessed by determining net production by the incubated muscles of tyrosine and 3-methylhistidine (3-MH) respectively. Both amino acids were determined by h.p.l.c. Both total and myofibrillar protein breakdown rates were higher in SOL than in EDL muscles and were decreased by incubating the muscles maintained at resting length, rather than flaccid. After fasting for 72 h, total protein breakdown (i.e. tyrosine release) was increased by 73% and 138% in EDL muscles incubated flaccid and at resting length respectively. Net production of tyrosine by SOL muscle was not significantly altered by fasting. In contrast, myofibrillar protein degradation (i.e. 3-MH release) was markedly increased by fasting in both muscles. When tissue was incubated in the presence of 1 munit of insulin/ml, total protein breakdown rate was inhibited by 17-20%, and the response to the hormone was similar in muscles incubated flaccid or at resting length. In contrast, myofibrillar protein breakdown rate was not altered by insulin in any of the muscle preparations. The results support the concepts of individual regulation of myofibrillar and non-myofibrillar proteins and of different effects of various conditions on protein breakdown in different types of skeletal muscle. Thus determination of both tyrosine and 3-MH production in red and white muscle is important for a more complete understanding of protein regulation in skeletal muscle.

Animals↗
PubMed1990

Corticosterone alone does not explain increased muscle proteolysis in septic rats.

The mediators and mechanisms of muscle proteolysis in sepsis are not fully known. We investigated the role of corticosterone in increased muscle proteolysis during sepsis in rats. In one series of experiments, plasma corticosterone and total and myofibrillar protein breakdown rates, determined in incubated extensor digitorum longus muscles as release of tyrosine and 3-methylhistidine, respectively, were measured 16 hr after sham operation (control) or cecal ligation and puncture (sepsis). In other experiments, corticosterone (10 mg/100 g body wt) was injected subcutaneously twice over 16 hr; thereafter, plasma hormone levels and muscle protein breakdown rates were determined. Plasma corticosterone was increased from 14 +/- 1 micrograms/dl in control rats to 38 +/- 8 micrograms/dl in septic rats and total and myofibrillar protein breakdown rates were increased by 99 and 326%, respectively, in muscles from septic rats. When administration of corticosterone resulted in plasma levels similar to those observed in septic rats, total or myofibrillar protein breakdown rates were not altered. The results suggest that corticosterone alone is not responsible for increased muscle proteolysis in septic rats. The data, however, do not rule out the possibility that glucocorticoids may be a cofactor to some other substance or substances in the induction of muscle proteolysis during sepsis.

Animals↗
PubMed1990

Effects of elevated temperature on protein breakdown in muscles from septic rats.

Elevated temperature has been proposed to contribute to accelerated muscle protein degradation during fever and sepsis. The present study examined the effect of increased temperature in vitro on protein turnover in skeletal muscles from septic and control rats. Sepsis was induced by cecal ligation and puncture (CLP); control rats were sham operated. After 16 h, the extensor digitorum longus (EDL) and soleus (SOL) muscles were incubated at 37 or 40 degrees C. Protein synthesis was determined by measuring incorporation of [14C]phenylalanine into protein. Total and myofibrillar protein breakdown was assessed from release of tyrosine and 3-methylhistidine (3-MH), respectively. Total protein breakdown was increased at 40 degrees C by 15% in EDL and by 29% in SOL from control rats, whereas 3-MH release was not affected. In muscles from septic rats, total and myofibrillar protein breakdown was increased by 22 and 30%, respectively, at 40 degrees C in EDL but was not altered in SOL. Protein synthesis was unaffected by high temperature both in septic and nonseptic muscles. The present results suggest that high temperature is not the primary mechanism of increased muscle protein breakdown in sepsis because the typical response to sepsis, i.e., a predominant increase in myofibrillar protein breakdown, was not induced by elevated temperature in normal muscle. It is possible, however, that increased temperature may potentiate protein breakdown that is already stimulated by sepsis because elevated temperature increased both total and myofibrillar protein breakdown in EDL from septic rats.

Animals↗
PubMed1990

Interaction between corticosterone and tumor necrosis factor stimulated protein breakdown in rat skeletal muscle, similar to sepsis.

Protein synthesis and breakdown rates were determined in incubated extensor digitorum longus muscles of rats treated with tumor necrosis factor (TNF; 20 micrograms/100 gm body weight), corticosterone (20 mg/100 gm body weight), or a combination of the two substances. Protein synthesis was measured as incorporation of carbon 14-labeled phenylalanine into protein. Total and myofibrillar protein breakdown rates were assessed as release of tyrosine and 3-methylhistidine, respectively. Administration of TNF alone did not affect muscle protein turnover rates. Corticosterone inhibited muscle protein synthesis and stimulated total and myofibrillar protein breakdown. When TNF was administered together with corticosterone, total and myofibrillar protein breakdown rates were increased further compared with rats treated with corticosterone alone. Because plasma corticosterone levels in rats treated with both TNF and the glucocorticoid were higher than in animals treated with corticosterone alone, it is possible that muscle proteolysis noted after TNF, injected together with costicosterone, was caused by the high glucocorticoid levels. To test that hypothesis, corticosterone alone or in combination with TNF was injected in rats that had undergone adrenalectomy. In these experiments, TNF did not increase plasma corticosterone levels or muscle protein breakdown rates. The results suggest that muscle catabolism induced by administration of TNF is mediated by glucocorticoids.

Adrenalectomy↗
PubMed1989

Protein synthesis in liver following infusion of the catabolic hormones corticosterone, epinephrine, and glucagon in rats.

The mediator(s) and mechanism(s) of acute-phase protein synthesis in the liver following injury and sepsis are not fully known. Elevated plasma levels of the catabolic hormones cortisol, glucagon, and epinephrine have been reported in trauma and sepsis. In previous reports, when these hormones were infused simultaneously (triple hormone infusion), several, but not all, of the metabolic alterations characteristic of sepsis occurred. In the current investigation, the effect of triple hormone infusion on hepatic protein synthesis was studied. Rats were infused intravenously during 16 hours with a solution containing corticosterone (4.2 mg/kg/h), glucagon (2.5 micrograms/kg/h), and epinephrine (6 micrograms/kg/h). Control animals were infused with a corresponding volume of vehicle. Total hepatic protein synthesis in vivo was measured with a flooding dose technique using [14C]-leucine. The synthesis of total secretory proteins and of the individual proteins albumin, complement component C3, and alpha 1-acid glycoprotein was measured in isolated, perfused liver using [3H]-leucine and a recirculating technique. Urinary excretion of nitrogen and plasma concentration of glucose were higher and plasma total amino acid concentration was lower in hormone-infused than in control rats. Total hepatic protein synthesis in vivo, expressed as the proportion of the protein pool that was replaced each day, was increased from 39% +/- 2% per day to 48% +/- 3% per day (P less than .05) by hormone infusion, but synthesis of secretory proteins in perfused liver was not significantly altered. The results suggest that although total hepatic protein synthesis may be increased by catabolic hormones, other mediator(s) are probably responsible for the stimulation of acute-phase protein synthesis in sepsis.

Acute-Phase Proteins↗
PubMed1989

Total and myofibrillar protein breakdown in different types of rat skeletal muscle: effects of sepsis and regulation by insulin.

Proteolysis is increased in sepsis, but it is not known whether myofibrillar and non-myofibrillar proteins are broken down in the same fashion, or respond to the same regulatory forces as in non-septic muscle. In this study, therefore, the effect of sepsis on total and myofibrillar protein breakdown in incubated rat extensor digitorum longus (EDL) and soleus (SOL) muscles was determined, and the response in vitro to different concentrations of insulin (10 to 10(5) microU/mL) of protein degradation was studied in incubated EDL muscles from control and septic rats. Sepsis was induced in rats weighing 40 to 60 g by cecal ligation and puncture (CLP). Control animals were sham operated. Sixteen hours after CLP or sham operation, intact EDL and SOL muscles were incubated for two hours in oxygenated Krebs-Henseleit bicarbonate buffer containing glucose (10 mmol/L) and cycloheximide (0.5 mmol/L), and total and myofibrillar protein breakdown was assessed from release into incubation medium of tyrosine and 3-methylhistidine (3-MH), respectively. Tyrosine and 3-MH were determined fluorometrically by high performance liquid chromatography (HPLC). Tissue levels of tyrosine and 3-MH remained stable both in control and septic muscles during incubation for two hours. The rate of tyrosine release was increased during sepsis by 58% (P less than .001) and 15% (NS) in EDL and SOL muscle, respectively. The corresponding figures for 3-MH were 103% (P less than .001) and 21% (NS). Tyrosine release was reduced by insulin at a concentration of 10(3) microU/mL in control muscle and at a concentration of 10(4) microU/mL in septic muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Do blood transfusions have adverse effects?].

The negative effects of blood transfusions, in the form of transfusion reactions, coagulation disorders, transfer of diseases such as hepatitis and AIDS, high costs etc, have prompted stricter indications for transfusion. In recent years, apart from these well known risks, the immuno-suppressive effect of blood transfusions has been observed and thereby the possible adverse influence on the prognosis in cases of malignant disease. The eventual connections between blood transfusions and the risk of both delayed healing and infection after routine surgery were reported in a study from Linköping. This review illustrates some of these rarely noticed potential risks of blood transfusions.

Humans↗
PubMed1987

Urinary excretion of 3-methylhistidine and creatinine and plasma concentrations of amino acids in hyperthyroid patients following preoperative treatment with antithyroid drug or beta-blocking agent: results from a prospective, randomized study.

The aim of this investigation was to compare the effects of a beta 1-selective adrenoceptor blocking agent and an antithyroid drug on urinary excretion of creatinine (Cr) and 3-methylhistidine (3-MH) and plasma concentrations of amino acids in hyperthyroid patients. beta-adrenoceptor blocking agents are increasingly used in the treatment of hyperthyroid patients, and the effects on clinical signs and symptoms mainly reflect beta 1-adrenoceptor blockade. The consequences of this treatment on metabolic alterations in hyperthyroidism are not fully known. In the present study, 30 hyperthyroid patients were randomized to preoperative treatment with the antithyroid drug methimazole + thyroxine (group I) or the beta 1-selective adrenoceptor blocking agent metoprolol (group II). Urinary excretion of Cr and 3-MH and plasma concentrations of amino acids were measured at the time of diagnosis, following preoperative treatment and 6 months postoperatively. Serum triiodothyronine (T3) was comparably elevated in the two groups of patients at the time of diagnosis and was normalized during preoperative treatment in group I but remained elevated during preoperative treatment in group II. Urinary excretion of creatinine was lower at the time of diagnosis than postoperatively, suggesting reduced muscle mass during hyperthyroidism. Urinary excretion of Cr increased during preoperative treatment in group I but was not significantly altered during treatment with metoprolol. The 3-MH/Cr ratio, which was higher at the time of diagnosis than postoperatively, indicating accelerated protein breakdown in skeletal muscle during hyperthyroidism, was reduced during preoperative treatment in group I but not in group II.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Effects of beta-blocking agents on urinary excretion of 3-methylhistidine during experimental hyperthyroidism in rats.

Beta-blocking agents are increasingly used as preoperative treatment of hyperthyroid patients. Relatively little is known about the effects of these drugs on metabolic alterations in hyperthyroidism. The aim of this investigation was to study the effects of two different beta-blocking agents on the urinary excretion of 3-methylhistidine (3-MH) during experimental hyperthyroidism in rats. Experimental hyperthyroidism was induced by daily intraperitoneal injections of triiodothyronine (T3; 100 micrograms/100 g body weight) for 3 days. Control animals were injected with corresponding volumes of solvent. Groups of rats received food enriched with metoprolol (8.8 mmol/kg of diet) or propranolol (3.3 mmol/kg of diet) or food without additions. Urinary 3-MH excretion was increased by about 40% during experimental hyperthyroidism. A similar increase of 3-MH excretion was found in animals receiving T3 + metoprolol, whereas the excretion of 3-MH was reduced to control level in hyperthyroid rats receiving propranolol. No effects of metoprolol or propranolol on 3-MH excretion were found in control animals. Although the source of 3-MH cannot be exactly defined, the present results indicate that increased proteolysis in skeletal muscle and/or other tissues during experimental hyperthyroidism was reduced by propranolol.

Adrenergic beta-Antagonists↗
PubMed1987

A retrospective analysis of a consecutive series of patients splenectomized for various hematologic disorders.

At our hospital, 47 out of 184 consecutive splenectomies performed over 7 recent years were carried out on patients afflicted with various hematologic diseases. The results of these 47 splenectomies were the subject of a careful retrospective analysis. The majority of the splenectomies (81%) were therapeutic. Cytopenia, particularly thrombocytopenia, was the most common indication for surgery. As a whole, good therapeutic responses with rapid improvements in peripheral blood picture and/or diminished symptoms of pressure discomfort from an enlarged spleen were obtained. There was no peri- or postoperative mortality; 23% major and 26% minor postoperative complications were recorded. In patients with perioperative bleeding and various postoperative complications, the spleens were larger than in subjects who run an uneventful peri- and postoperative course. During the follow-up period, 4 septicemias occurred in 3 patients. In 2 of these patients, the septicemias coincided with a cholecystitis and a pneumonia, respectively. None of the infections was lethal. It is concluded that elective splenectomy for hematologic disease in well selected and carefully prepared patients is beneficial and can be performed without mortality or major hazards.

Adrenal Cortex Hormones↗