Biomedical subjects

E Jansson

Publications and source records attributed to E Jansson.

At least 127 records · Page 7Linked to original sources

PubMed1988

Coenzyme Q10 content in different parts of the normal human heart.

Coenzyme Q10 (CoQ10) and citrate synthase (CS) activities were analysed in the myocardium of brain-dead organ donors (14-40 years). Different parts of the heart were studied: right and left auricular appendage, right and left atrium, right ventricle (septum and free wall) and left ventricle (septum, free wall, and papillary muscle). Freeze-dried, dissected myocardial samples were analysed for CoQ10 content by HPLC and CS activity by fluorometric technique. CoQ10 content in the normal human myocardium was lowest in auricular appendages and atria (0.25 +/- 0.06 mg X g-1 dry muscle), intermediate in right ventricle (0.37 +/- 0.05 mg X g-1 dm) and highest in left ventricle (0.42 +/- 0.07 mg X g-1 dm). CS activity showed the same relationship between these locations as CoQ10. The results suggest that there exist differences in CoQ10 content between different parts of the normal human myocardium. These differences were closely related to the differences in CS activity between corresponding parts. The differences between different parts of the heart may be related to divergent work demand, and the constant relationship between CS and CoQ10 may be related to their coupling to the mitochondrial oxidative metabolism.

Adult↗

PubMed1988

First isolations of Borrelia burgdorferi from rodents collected in northern Europe.

Spirochetes were found in 13% of Ixodes ricinus collected from an island, near Stockholm where human borreliosis is endemic. Borrelia burgdorferi was cultivated from the kidney and/or spleen of wild rodents (Clethrionomys glareolus and Apodemus flavicollis) from the same island. Spirochetes were identified as Borrelia burgdorferi by indirect immunofluorescence assays using species and genus specific monoclonal antibodies. In these tests the spirochetes could not be differentiated from strains previously cultured from Swedish patients with Ixodes-borne borreliosis. The results show that small rodents in Europe may harbour borreliae and indicate that C. glareolus and A. flavicollis may be important reservoirs for the spirochetes causing Ixodes-borne borreliosis in humans and domestic animals in Europe.

Animals↗

PubMed1988

Key enzymes of myocardial energy metabolism in patients with valvular heart disease: relation to left ventricular function.

Endomyocardial biopsies were taken from the apex of the left ventricle in 15 patients operated on for aortic valve disease or ischaemic heart disease and from papillary muscles in six patients operated on for mitral valve disease. Activities of cardiac phosphofructokinase (PFK), total lactate dehydrogenase (LD), its isoenzyme LD1, aspartate aminotransferase (ASAT), total creatine kinase (CK), its isoenzyme MB, citrate synthase (CS) and myoglobin content (MYO) were related to the angiographically determined left ventricular function. Activities of total LD, PFK and PFK/CS ratio were lower in patients with decreased, than in those with normal, left ventricular function. Myoglobin content and activities of CS and ASAT were not related to left ventricular function. It is suggested that depressed left ventricular contractility is associated with a decreased glycolytic capacity while the oxidative capacity is mainly unaltered.

Aged↗

PubMed1988

Increase in myoglobin content and decrease in oxidative enzyme activities by leg muscle immobilization in man.

Biopsies from m. quadriceps femoris from the operated leg of nine patients were taken before, and 6 weeks after, knee surgery. During the whole postoperative period the operated leg was immobilized with the knee in 40-50 degrees of flexion. Myoglobin (MYO) and the enzymes citrate synthase (CS), creatine kinase (CK) and its isozymes MB (CK-MB) and mitochondrial CK (CK-MIT), aspartate aminotransferase (ASAT), phosphofructokinase (PFK) and lactate dehydrogenase (LD) were determined on the biopsies. Citrate synthase, ASAT, CK, CK-MB, CK-MIT and LD activities were decreased (12-30%) after the postoperative leg immobilization period. Phosphofructokinase did not change, while MYO content was increased (16%). In conclusion, a different control of the synthesis of oxidative enzymes and MYO is suggested, as the induced changes following immobilization were in opposite directions. The function of the increased MYO content may be to facilitate the oxygen extraction.

Adolescent↗

PubMed1988

Increased IMP content in glycogen-depleted muscle fibres during submaximal exercise in man.

To study the relationship between glycogen depletion and IMP accumulation in different fibre types, single fibres were dissected from biopsies taken at rest and after one hour of exercise at 70% of maximal oxygen uptake. These fibres were analysed histochemically for glycogen and fibre types and pooled into classes of type I or type II fibres with low, medium or high glycogen content, in a total of six classes. These pools were analysed for ATP, ADP, AMP and IMP contents by high performance liquid chromatography. The contents of ATP, ADP and AMP at rest, and immediately after exercise, were not significantly different between the six fibre classes. The IMP content in glycogen-depleted fibres obtained after exercise was, however, higher than in pools of glycogen-filled fibres obtained both at rest and after exercise. In conclusion, the elevated IMP content in glycogen-depleted but not in glycogen-filled type I and type II muscle fibres during prolonged submaximal exercise indicates a decreased ATP regeneration rate in glycogen-depleted fibres, which may be a factor limiting exercise duration during prolonged submaximal exercise.

Adenosine Diphosphate↗

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

Increased removal rate of exogenous triglycerides after prolonged exercise in man: time course and effect of exercise duration.

Ten healthy young men exercised for 1.5 and 3 hours, respectively, 4 to 6 weeks apart at the same work intensity, corresponding to 77% of the individual maximal heart rate. In the fasting state 1 mL of 10% Intralipid/kg body weight was injected IV, the fractional removal rate was calculated (k2-value), and fasting lipid and apolipoprotein C-I, C-II, and CIII concentrations were determined one day before, immediately before, immediately after, and one day after the exercise: measurements were also made two and three days after the three-hour session. An increase of the k2-value was found only the day after the three-hour exercise (+66%, P less than .01), while after the 1.5-hour exercise the k2-value was not changed. One and two days after the three-hour exercise the fasting serum triglyceride concentration was significantly decreased by 33% and 16%, respectively. Serum triglyceride concentration was decreased also the day after the shorter session (-17%, P less than .05). Decreases in serum cholesterol concentrations were significant after both exercise bouts, but the significance disappeared if corrections for the changes in calculated plasma volume were made. Serum level of C apolipoproteins was decreased one day after the three-hour exercise, while it was not changed after the shorter exercise. This study shows that prolonged exercise produces an increase in the removal rate of Intralipid triglycerides from the bloodstream, that this change is related to the duration of exercise, and that some time is required following the exercise, before it is manifest.

Adult↗

PubMed1987

Muscle fiber characteristics in female dancers during an active and an inactive period.

Muscle biopsies were taken from female dancers, aged 24 +/- 2 years, first during an active period and then after 32 weeks of detraining. During the active period, the percentage of type I fibers was 63% +/- 12%, and of the subgroups IIA, IIB, and IIC, 26% +/- 9%, 8% +/- 7%, and 3% +/- 3%, respectively. There was no significant change due to detraining either in the proportion of type I fibers or in the type II subgroups. During the active period, the cross-sectional area of the type I fibers was 3798 +/- 586 micron 2. The areas of the subgroups IIA, IIB, and IIC were 3394 +/- 858, 2497 +/- 530, and 3296 +/- 638 micron 2, respectively. After the detraining period, the area of the type I fibers had increased significantly (P less than 0.05). The areas of the types IIA, IIB, and IIC tended to be increased although not significantly. It is suggested that the comparatively high percentage of type I fibers, which was found in the active dancers, is the result of selection rather than of training, while the small fiber areas seem to be due to training.

Adult↗

PubMed1987

Myocardial enzyme activities in patients with mitral regurgitation or mitral stenosis.

To determine the adaption of myocardial metabolism in mitral regurgitation and mitral stenosis, human papillary muscles obtained during open heart surgery were analysed to measure selective enzyme activities in energy metabolism. All enzyme activities were expressed per unit dry weight muscle, per unit alkali soluble protein, and per unit total creatine and the different results compared. The activities of enzymes concerned with mitochondrial energy production and energy transfer (namely, citrate synthase and mitochondrial creatine kinase) tended to be higher in papillary muscles from hearts with mitral regurgitation than in those with mitral stenosis. The activities of enzymes concerned with cytoplasmic energy production (creatine kinase MM, lactate dehydrogenase, and phosphofructokinase) did not show statistically significant differences between mitral regurgitation and mitral stenosis. The ratio of creatine kinase MB activity to total creatine content showed the greatest difference when papillary muscles from patients with mitral regurgitation and mitral stenosis were compared (31% higher in mitral regurgitation; p less than 0.001). The specific function of creatine kinase MB, which is located in cytoplasm, is not well defined. Creatine kinase MB activity increases with extreme endurance training of human skeletal muscle. Thus the higher creatine kinase MB activity in papillary muscle of mitral regurgitation may represent an adaptation to increased physical demand.

Adult↗

PubMed1987

Adenine nucleotide degradation in the human myocardium during cardioplegia.

The tissue content of adenine nucleotides and their metabolites, inosine monophosphate, adenosine, hypoxanthine, and uric acid, were determined in biopsy specimens from the left ventricle of six patients during cardioplegia for open heart surgery. Biopsy specimens were collected immediately after the induction and at the end of cardioplegia (51-82 min) and were analysed by high performance liquid chromatography. After the induction of cardioplegia (cold potassium enriched solution) the left coronary artery was continuously perfused with cold (10 degrees C), potassium enriched, diluted blood. The adenosine triphosphate concentration decreased from 13 to 8 mmol.kg-1 dry muscle (p less than 0.01) during cardioplegia. Adenosine diphosphate and adenosine monophosphate concentrations were 6 and 3 mmol.kg-1 dry muscle respectively and remained unaffected. The adenosine concentration (0.3 mmol.kg-1 dry muscle) was three times higher than that of inosine monophosphate. Inosine concentrations increased from 0.8 to 2.7 mmol.kg-1 dry muscle (p less than 0.01) in parallel with the increase in hypoxanthine from 0.1 to 0.4 mmol.kg-1 dry muscle (p less than 0.01). The total adenine nucleotide pool decreased by 5 mmol.kg-1 dry muscle (p less than 0.01), whereas the corresponding increase in nucleotides and bases only was 2 mmol.kg-1 dry muscle. In conclusion, the adenosine triphosphate content and the adenine nucleotide pool were appreciably reduced during continuous cold blood cardioplegia as used in the present study. The tissue content of adenosine and further metabolites was considerably increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine Nucleotides↗

PubMed1987

ATP and IMP in single human muscle fibres after high intensity exercise.

Within a muscle there is large variation in the activity of various enzymes among single fibres. It is reasonable, therefore, to expect a corresponding variation in their metabolic response to exercise. This was examined by obtaining muscle biopsies from five men at rest and after intense short-term exercise consisting of three bouts of 30 knee extensions each and intervened by 60 s rest. Freeze-dried dissected single fibres identified as type 1 or type 2 were analysed for ATP and IMP contents by liquid chromatography. Rest. Average ATP tended to be higher in type 2 than in type 1 fibres. The ATP range was 14-30 and 14-32 mmol X kg-1 dry muscle (dm) in type 1 and 2 fibres, respectively. IMP was less than 1 mmol X kg-1 dm in most fibres and similar in types 1 and 2. Exercise. Muscle force decreased 70% during exercise. The average decrease in ATP content was significant for both fibre types with somewhat larger response for type 2 (20%) than type 1 (10%) fibres. The ATP range was 10-28 and 10-30 mmol X kg-1 dm in type 1 and 2 fibres, respectively. Average IMP content increased substantially in both fibre types, more so for type 2, and the range for individual fibres was 0-13 (type 1) and 0-21 (type 2) mmol X kg-1 dm. Conclusion. After exhaustive short-term exercise, a large variation in ATP and IMP contents was evident among single type 1 and type 2 fibres. None of the fibres, however, showed an ATP content lower than 10 mmol X kg-1 dm.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Monophosphate↗

PubMed1987

ATP breakdown products in human skeletal muscle during prolonged exercise to exhaustion.

To study changes in muscle energy state during prolonged exercise, especially in relation to fatigue, muscle biopsies were obtained from seven healthy males working until exhaustion on a cycle ergometer at 68% (63-74%) of their maximal oxygen uptake. Biopsies were taken at rest, after 15 and 45 min of exercise and at exhaustion, and analysed for ATP, ADP, AMP, inosine monophosphate (IMP) and hypoxanthine content by high performance liquid chromatography (HPLC), and for creatine phosphate (CP), lactate and glycogen by enzymatic fluorometric techniques. Glycogen content at exhaustion was approximately 30% of the pre-exercise level. The CP content decreased steeply during the first 15 min of exercise (P less than 0.01) and continued to decrease during the rest of the exercise period (P less than 0.05). Pronounced increases in contents of IMP (64% P less than 0.001) and hypoxanthine (69%, P less than 0.05) were found when exhaustion was approaching. Furthermore, energy charge [EC; (ATP + 0.5 ADP)/(ATP + ADP + AMP)] was decreased at exhaustion (P less than 0.05). The increases in IMP and hypoxanthine which occurred when exhaustion was approaching during prolonged submaximal exercise together with the decrease in EC during this phase of exercise suggest a failure of the exercising skeletal muscle to regenerate ATP at exhaustion.

Adenosine Diphosphate↗

PubMed1987

Myocardial energy metabolism in the induction phase of cardioplegia in relation to myocardial temperature during open heart surgery.

Changes in myocardial high energy phosphate and lactate concentrations during initiation of cardioplegia for open heart surgery were studied in 21 patients and related to their individual myocardial temperatures. Left ventricular myocardial biopsies were taken 10 min post aortic cross-clamping and were analysed for ATP, creatine phosphate (CP), creatine (C) and lactate. The patients were divided into three groups according to the achieved myocardial temperature: 6-10 degrees C, 11-15 degrees C and 16-24 degrees C. The results indicated that optimal myocardial protection during the induction phase of the cardioplegia was obtained in the 11-15 degrees C group in which the highest ATP concentration and simultaneously lowest lactate concentration was maintained.

Adenosine Triphosphate↗

PubMed1987

Changes in elemental composition of human muscle fibres following surgery and immobilization. An X-ray microanalytical study.

X-ray microanalysis of single muscle fibres visualized in the electron microscope has been applied to human muscle biopsies to quantify changes of intracellular elements after knee-surgery with subsequent immobilization for 6 weeks. An increase of intracellular chlorine (Cl; P less than 0.001) and of sodium (Na; P less than 0.1) concentrations were found 1 and 6 weeks post-surgery. Intracellular potassium (K), phosphorus and sulphur concentrations were not significantly changed. The increased Cl and Na concentrations may be an indication of a decreased activity of the ATPase-dependent Na/K-pump in the sarcolemma and/or of an increased sarcolemmal permeability for Na and Cl.

Adult↗

PubMed1987

Substrate utilization and enzymes in skeletal muscle of extremely endurance-trained men.

Substrate utilization during exercise at 65% of maximal O2 uptake (VO2 max) and biochemical characteristics of vastus lateralis were compared between five endurance-trained (T) and five untrained subjects (U). The oxidative enzyme activities were 100% greater in T than in U, and VO2 max was 50% higher. A greater proportion of ATP regeneration occurred through oxidative processes in T than in U (smaller leg lactate release and smaller muscle lactate accumulation). The respiratory exchange ratio together with the local leg respiratory quotient indicated a greater contribution of fat to oxidative metabolism in T than U (53 vs. 33%). No difference, however, in the ratio of plasma free fatty acid extraction to O2 extraction by the working legs was found between T and U. Thus it could be calculated that a greater fraction of fat oxidation would have been covered by intramuscular triglycerides in T than in U (34 vs. 15%, P less than 0.05). T in comparison to U were further characterized by a smaller glycogen breakdown and a smaller glucose uptake, which may have been one contributing factor that prevented the blood glucose level from falling in T. The greater leg muscle citrate concentration in T could have been one factor mediating a lower carbohydrate utilization as a response to an increase in the relative proportion of fat oxidation.

Bicycling↗

PubMed1987

Preservation of myocardial high-energy phosphates in open-heart surgery with deep general hypothermia and multidose crystalloid cardioplegia.

Myocardial energy metabolism during deep general hypothermia (20 degrees C) and multidose crystalloid cardioplegia, and also during subsequent reperfusion, was studied in eight patients undergoing isolated aortic valve replacement. Six serial transmural biopsy samples from the left ventricular apex were analyzed for high-energy phosphates and their degradation products. Reductions in ATP, total adenine nucleotide content and energy charge were insignificant during cardioplegia, as were changes in adenosine and uric acid concentrations. During reperfusion, however, there was slight but significant reduction in total adenine nucleotide content, despite adequate oxygenation as indicated by reversal of lactate accumulation. These observations suggest that the reperfusion phase is accompanied by metabolic aberrations which are not overcome by good oxygenation in relation to the metabolic rate.

Adenine Nucleotides↗

PubMed1987

Sprint training effects on muscle myoglobin, enzymes, fiber types, and blood lactate.

The purpose of this study was to determine if changes in intra-muscular myoglobin concentration accompany histochemical and enzymatic adaptations to supra-maximal exercise training. Subjects were assigned to either a training group (N = 11), who trained 2 to 3 times weekly for 6 wk, or a control group (N = 6). Training progressed from two 15-s and two 30-s "all-out" sprints on a cycle ergometer during week 1 to six 15-s and six 30-s bouts per session during week 6. The Wingate test was performed before and after the 6 wk, but performance variables were not changed in either group. In the training group, peak lactate after the Wingate test was significantly higher after training. No significant changes in enzyme activities, myoglobin concentration, or fiber-type frequency were observed in the control group. In contrast, in the training group, the percent fast twitch oxidative fibers increased, myoglobin decreased, and both citrate synthase and phosphofructokinase activities increased (P less than 0.05). The results suggest that muscle myoglobin concentration is not increased by 6 wk of supra-maximal exercise training and that such training induces cellular adaptations without accompanying performance changes. Alternatively, the Wingate test is not a sensitive test of adaptations to the training.

Adult↗

PubMed1987

Effect of food deprivation on survival after hemorrhage in the rat.

The changes in plasma glucose concentration and hematocrit during, and 7-day survival after, 60-min hemorrhagic hypotension (55 mmHg MAP) were investigated in postprandial and 6- or 24-h food-deprived rats. During hemorrhage, postprandial rats developed hyperglycemia, 30% greater than 6-h and 150% higher than 24-h food-deprived rats. Blood loss and plasma refill were greater in postprandial rats compared to 24-h food-deprived rats. Food deprivation for 24 h resulted in significantly increased mortality (6/13) posthemorrhage. All postprandial rats survived (13/13). A further three groups of animals deprived of food for 24 h were submitted to hemorrhage volume similar to that of postprandial rats. When no infusion was given during hemorrhage all rats died after hemorrhage (10/10). Saline infusion did not increase survival. Infusion of a similar volume of hypertonic glucose resulted in improved survival (not significant vs postprandial). Short-term food deprivation alters responses to stress and influences the outcome after standardized hemorrhage. Induction of hyperglycemia during hemorrhage was associated with survival.

Animals↗