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Biomedical subjects

E Jansson

Publications and source records attributed to E Jansson.

At least 163 records · Page 9Linked to original sources
PubMed1983

Myoglobin concentration in single type I and type II muscle fibres in man.

Histochemical visualization of myoglobin in a benzidine peroxidase reaction suggests that human skeletal muscle fibres are differentiated into fibres having either high or a low myoglobin content. In the present study myoglobin was quantified in single human muscle fibres after being classified as either type I ("slow-twitch") or type II ("fast twitch"). Samples were obtained from m. quadriceps femoris in 4 healthy untrained male subjects using the needle biopsy technique. After freeze-drying, individual fibres were dissected out and classified as either type I or type II by a myofibrillar ATPase stain. Myoglobin analyses were performed on these single fibres by a radioimmunoassay. The myoglobin concentrations were found to be significantly higher in type I than in type II muscle fibres in all 4 subjects and were, on the average, of the same magnitude as found in larger (mixed muscle) samples. The myoglobin concentration ratio between type I and type II fibres ranged from 1.4 to 1.7.

Humans↗
PubMed1983

Adaptation of human skeletal muscle to endurance training of long duration.

The aim of this study was to examine the adaptive response of skeletal muscle to dynamic training of long duration and low intensity. The response of m. triceps brachii, (TB) and m. quadriceps femoris, vastus lateralis (VL) to training of long duration at an intensity corresponding to approximately 45% of VO2 max, has been studied in six subjects. Muscle specimens were taken during training (18.5 miles (30 km)), which involved skiing with a backpack, (6 days/week, 8 weeks), as well as during a subsequent period of detraining (33 weeks). Increases in oxidative enzyme activities and capillarization during training were limited to the TB. There were parallel increases in citrate synthase (CS) and malate dehydrogenase (MDH) during the first 3 weeks of training (30%). CS then continued to rise (to 90% above pretraining level), while the increase in MDH levelled off. The activity of 3-hydroxyacyl-CoA-dehydrogenase (HAD) and the number of capillaries per fibre increased by 50% and 40% respectively. A selective decrease (12%) in area of fibre type IIA was noted during training after a 2-week period of energy deficiency. During the first 6 weeks of detraining, the decrease in CS and HAD (30%) was greater than the decrease in capillaries per fibre (14%). It is concluded that prolonged duration of training is not, in itself, sufficient to elicit an adaptive response in the leg muscles, while a modest training effect was seen for the arm muscles. The finding emphasizes the importance of adequate intensity in physical training programmes.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1983

Human myocardial and skeletal muscle enzyme activities: creatine kinase and its isozyme MB as related to citrate synthase and muscle fibre types.

Activities of myocardial and skeletal muscle total creatine kinase (CK) and its isozyme MB were related to the oxidative capacity [measured as the citrate synthase (CS) activity] and to the contractile characteristics (estimated as the percentage of type I muscle fibres). Skeletal muscle biopsies were obtained both from physically trained and untrained men and myocardial biopsies from patients subjected to open-heart surgery performed because of mitral or aortic valve disease. Enzyme activities were determined on freeze-dried muscle specimens. The CK-MB activity was about twice as high in trained skeletal muscle as in untrained ones reaching the myocardial level. The total CK activity was about three times higher in skeletal muscle than in myocardium; the myocardium, however, had CS activity 3-4 times larger than that of skeletal muscle. A close correlation was demonstrated between activities of CK-MB on one hand and CS (r = 0.76) or percentage type I fibres (r = 0.83) on the other hand suggesting a connection between CK-MB activity and the oxidative capacity of the cell. This was in contrast to total CK where different regressions were obtained when comparing the myocardium and the skeletal muscle of trained or untrained men. In conclusion, CK-MB activity in trained skeletal muscle in athletes were similar to that in myocardium. CK-MB was related to the oxidative capacity and formation of cellular energy in skeletal and heart muscle.

Adult↗
PubMed1983

Sound levels recorded within the symphony orchestra and risk criteria for hearing loss.

Investigations into noise-induced hearing loss should consist of two parts: a mapping of the sound environment and a charting of hearing loss. This paper is the first part of such an investigation: a mapping of sound levels and sound spectra within the symphony orchestra. It was found that 'heavy' symphonic music exceeds the permitted dose for industrial noise equivalent to 85 dB(A) for a full working week. The permitted noise dose is reached for 'heavy' music after a working time of 10 hours per week in 'exposed' positions, such as in front of trumpets, and after 25 hours in 'normal' positions. A simple method to estimate the 'noise' exposure in equivalent sound level for combination of different sorts of music has been developed.

Hearing Loss, Noise-Induced↗
PubMed1982

Training-induced increase in myofibrillar ATPase intermediate fibers in human skeletal muscle.

The response of human muscles triceps brachii and vastus lateralis to training, consisting of 18.5 miles a day of skiing with a backpack, 6 days a week for 8 weeks, has been investigated by means of histochemical fiber typing (myofibrillar ATPase) as well as immunohistochemical discrimination of slow and fast myosin (n = 6). A detraining period of 33 weeks was also studied. The percentage of type 2 fibers decreased by 6% in the triceps brachii during training, whereas the intermediate fiber type increased by 4%. No change was found in the distribution of fiber types in the vastus lateralis during training or in both muscles during detraining. The ATPase intermediate fibers also stained intermediately in the immunohistochemical stainings for slow and fast myosin. These results show that transformation of a fraction of the type 2 fibers into the intermediate type may occur as a response to endurance training.

Adenosine Triphosphatases↗
PubMed1982

On the significance of the respiratory exchange ratio after different diets during exercise in man.

Total respiratory exchange ratio (R) was compared to the respiratory exchange ratio over the legs (RQL) during exercise after different diets, to evaluate if R (which represents a mean for the whole body) can be used to estimate the relative proportions of fat and carbohydrate oxidation in exercising muscle. One important prerequisite for this is a steady state acid base balance, 7 subjects were studied at rest and during the later part of a 25 min exercise (65% of Vo2 max) on two occasions, the first preceded by a fat rich diet and the second by a carbohydrate rich diet. Oxygen uptake, R and arterial-femoral venous differences for [O2], [CO2], PCO2 and pH and arterial concentrations for lactate and beta-hydroxybutyrate were measured. Respiratory exchange ratio over the exercising legs (RQL) and ventilation/oxygen uptake were calculated. Arterial pH, PCO2, lactate and beta-hydroxybutyrate as well as specific ventilation attained steady levels during the later part of exercise after both diets. Although arterial lactate and beta-hydroxybutyrate differed between the diets, the arterial pH and specific ventilation were the same. Both R and RQL were higher after the carbohydrate than after the fat diet and there was no systematic difference between R and RQL. Therefore, it seems likely that R estimates the proportion of fat and carbohydrate oxidation in skeletal muscle during submaximal exercise after extreme diets.

3-Hydroxybutyric Acid↗
PubMed1982

Diet induced changes in sympatho-adrenal activity during submaximal exercise in relation to substrate utilization in man.

In order to study how the diet may influence sympatho-adrenal activity during exercise, 7 subjects were examined at rest and during submaximal exercise (25 min at 65% of VO2 max) on two occasions. The first occasion was preceded by 5 days on a carbohydrate poor diet (5% carbohydrate, 72% fat and 23% protein) and the second one by 5 days on a carbohydrate rich diet (78% carbohydrate, 8% fat and 14% protein) with the same energy content. Oxygen uptake, respiratory exchange ratio (R), heart rate and arterial plasma concentrations of adrenaline, noradrenaline, dopamine, insulin, glucose, lactate, free fatty acids (FFA), glycerol and beta-hydroxybutyrate were measured at rest and during exercise. Oxygen uptake and heart rate during exercise were higher and R was lower after the carbohydrate poor than after the carbohydrate rich diet. During exercise the arterial plasma concentrations of FFA, glycerol and beta-hydroxybutyrate were higher after the carbohydrate poor than after the carbohydrate rich diet whereas concentrations of insulin and lactate were lower. At rest arterial plasma noradrenaline and adrenaline levels were similar on the two diets (0.70 +/- 0.31 nM noradrenaline and 0.35 +/- 0.32 nM adrenaline one the carbohydrate rich diet, mean values +/- SD). Exercise induced increases in noradrenaline were more pronounced after the carbohydrate poor than after the carbohydrate rich diet (12.42 +/- 3.41 vs. 7.45 +/- 2.68 at 25 min of exercise, p less than 0.001). A similar, although more variable accentuation of exercise induced increases in adrenaline was found. It is concluded that, when compared to a carbohydrate rich diet, a carbohydrate poor diet increases the relative contribution of fat to oxidative metabolism and increases the sympatho-adrenal response to exercise. Stimulation of lipolysis by sympatho-adrenal mechanisms might be of importance for the substrate availability when carbohydrate intake in low.

3-Hydroxybutyric Acid↗
PubMed1982

Effect of diet on the utilization of blood-borne and intramuscular substrates during exercise in man.

20 subjects were studied at rest and during a 25 min submaximal exercise (65% of VO2 max) on two occasions, the first preceded by a fat rich diet and the second by a carbohydrate rich diet. Oxygen uptake, respiratory exchange ratio (R) and arterial-femoral venous differences for glucose, lactate, beta-hydroxybutyrate and FFA (based on the fractional extraction of 3H-palmitate) were measured at rest and during exercise. Changes in intramuscular glycogen, triglyceride and lactate concentrations were determined in muscle biopsies taken before and immediately after exercise form m. quadriceps femoris. R was lower after the fat than after the carbohydrate diet and simultaneously the FFA extraction by the exercising leg was higher. The muscle triglycerides did not changes significantly during exercise after either diet. The glucose extraction was insignificantly greater after the fat diet. The glycogen reduction was numerically smaller after the fat diet, but the difference was uncertain and difficult to evaluate due to a large variation after the carbohydrate diet. However, muscle lactate accumulation and release by the exercising leg was smaller after the fat diet, indicating a slower rate of muscle glycogenolysis. It is concluded that a fat rich diet increases the relative contribution of fat to the oxidative metabolism, that this increase, to a great extent, is covered by plasma FFA and that the concomitant decrease in carbohydrate utilization concerns muscle glycogen rather than blood glucose.

Adult↗
PubMed1982

Effect of diet on muscle glycogen and blood glucose utilization during a short-term exercise in man.

7 subjects were studied at rest and during a 6 min submaximal exercise (65% of VO2 max) on two occasions, the first preceded by a fat rich diet and the second by a carbohydrate rich diet. Oxygen uptake and respiratory exchange ratio (R) were measured at rest and heart rate both at rest and during exercise. Arterial-femoral venous differences for oxygen, glucose, lactate and beta-hydroxybutyrate and arterial concentrations of free fatty acids were measured at rest and during exercise. Changes in muscle glycogen (in 6 subjects) and lactate concentration were determined by biopsies from m. quadriceps femoris taken before and immediately after exercise. Muscle glycogen decreased less during exercise after the fat than after the carbohydrate diet in 5 of the 6 subjects, whereas blood glucose extraction by the exercising legs did not change with diet. Muscle lactate accumulation and release were smaller after the fat diet. In conclusion, the muscle glycogen utilization during a short-term exercise appeared to be lower after the fat than after the carbohydrate diet, but not the concomitant blood glucose extraction. These differences between diets were similar to those observed after a more prolonged work at the same load.

Adult↗
PubMed1982

Serological characterisation of Ureaplasma urealyticum strains by enzyme-linked immunosorbent assay (ELISA).

A modification of enzyme-linked immunosorbent assay (ELISA) was developed for the serological characterisation and identification of strains of Ureaplasma urealyticum. The eight recognised human serotypes of U urealyticum and antisera produced against them were used as reference for the evaluation and standardisation of the method. The serological profile illustrating reactions of antigen with homologous and heterologous antisera was specific and reproducible for each serotype. The homologous reaction was always very prominent but some cross-reactivity was seen, most clearly between serotypes 2 and 5. The method was found to be suitable for serological typing of clinical isolates of U urealyticum because of rapid and simple technical procedure, good reproducibility of the results and economical consumption of antisera and other reagents.

Antigens, Bacterial↗
PubMed1982

Viruses of mycoplasmas and spiroplasmas.

Acholeplasmas, mycoplasmas and spiroplasmas of the class Mollicutes have been shown to carry DNA viruses. Morphologically they occur as rods, polyhedrons with short or long tails and as enveloped spheres. These latter resemble enveloped nonlytic animal viruses and are now placed in the new family of bacterial viruses the Plasmaviridae. Viruses of mycoplasmas and spiroplasmas present a suitable experimental model for studies of the virus-cell interactions.

Acholeplasma↗
PubMed1982

Isolation and preliminary characterisation of mycoplasmavirus 20-P.

A mycoplasmavirus, MV 20-P, was isolated from the fastidious, slow-growing human mycoplasma 20-P, previously identified by the growth inhibition test as Mycoplasma hominis type 2. Its broth culture was ultracentrifuged into 35% saccharose, the pellet was resuspensed in buffer, and the suspension was dropped onto laws of the virus indicator Acholeplasma laidlawii BCL-13. The virus was washed off the plaque areas by buffer. MV 20-P appeared in electron microscopy as spherical, enveloped particles about 80 nm in diameter. It was sensitive to lipid solvents. These preliminary results indicate that MV 20-P is a MVL2 type mycoplasmavirus and possibly the first of human origin.

Adsorption↗
PubMed1981

Fiber type area and metabolic potential of the thigh muscle in man after knee surgery and immobilization.

The muscle atrophy of the quadriceps muscle was investigated in patients after knee operations and immobilization in a long leg plaster cast. Muscle biopsies were taken before operation and after 5 weeks immobilization. The activity of oxidative (SDH) and glycolytic (PFK) enzymes was determined. The fiber area of the different fiber types were measured and enzyme activities in single characterized fibers were analyzed. A selective type 1 atrophy was found with a reduced cross-cut area of the type 1 fiber, and a reduced oxidative enzyme activity occurred in the slow-twitch type 1 fibers. The effect of the muscle tension in the immobilized leg and the inhibiting role of the postoperative pain is discussed.

Adult↗
PubMed1981

Time course of muscle metabolic changes during tourniquet ischemia in man.

Muscle biopsies form the vastus lateralis muscle of the thigh were obtained from 11 patients before and at 15-min intervals following tourniquet application and 15 min after tourniquet release. The total circulatory occlusion time varied from 60 to 120 min. The concentrations of lactate, creatine phosphate and adenosine triphosphate were determined, and the muscle temperature was recorded. During the ischemic period, the lactate concentration increased from 1.9 mmol x kg-1 wet wt to 14.9 mmol x kg-1 wet wt after 90 min of ischemia. During the last 30 min of ischemia, no further increase in lactate concentration was observed. The creatine phosphate concentration decreased from 20.4 to 5.2 mmol x kg-1 wt wt after 120 min of ischemia. The temperature fell rapidly during the first 15 min from 35.9 degrees to 33.5 degrees and was then constant until 95 min when a further small decrease was observed. The adenosine triphosphate concentration did not change significantly during the ischemic period.

Adenosine Triphosphate↗
PubMed1981

Acid soluble and insoluble glycogen in human skeletal muscle.

Quantitative biochemical analysis of glycogen was performed with and without perchloric acid pretreatment on biopsy specimens of varying glycogen content, obtained at rest and immediately after exercise after different diets. If analysis was carried out after perchloric acid pretreatment, as is commonly done, lower values were obtained than without such pretreatment. This could be explained by the existence of glycogen in forms of greater and lesser solubility. Evidence for this was obtained by quantitative analysis of glycogen in the perchloric acid extract. The acid soluble form in the extract constituted a greater fraction of total glycogen at supra-normal than at low concentrations. This might also explain why supra-normal levels of glycogen cannot be detected by histochemical methods. The existence of soluble and insoluble glycogen may also be of physiological importance, e.g. by interacting differently with enzymes of glycogen metabolism.

Adult↗