Biomedical subjects

E Jansson

Publications and source records attributed to E Jansson.

At least 55 records · Page 3Linked to original sources

PubMed1999

Metabolic response in type I and type II muscle fibers during a 30-s cycle sprint in men and women.

The acute metabolic response to sprint exercise was studied in 20 male and 19 female students. We hypothesized that the reduction of muscle glycogen content during sprint exercise would be smaller in women than in men and that a possible gender difference in glycogen reduction would be higher in type II than in type I fibers. The exercise-induced increase in blood lactate concentration was 22% smaller in women than in men. A considerable reduction of ATP (50%), phosphocreatine (83%), and glycogen (35%) was found in type II muscle fibers, and it did not differ between the genders. A smaller reduction of ATP (17%) and phosphocreatine (78%) was found in type I fibers, and it did not differ between the genders. However, the exercise-induced reduction in glycogen content in type I fibers was 50% smaller in women than in men. The hypothesis was indeed partly confirmed: the exercise-induced glycogen reduction was attenuated in women compared with men, but the gender difference was in type I rather than in type II fibers. Fiber-type-specific and gender-related differences in the metabolic response to sprint exercise might have implications for the design of training programs for men and women.

Adenosine Triphosphate↗

PubMed1998

[Reduced morbidity and the risk of premature death. Regular physical exercise is beneficial for health at all ages].

Regular physical activity yields benefits to men and women of all ages. The risk of premature death is reduced, as is that of incurring or dying of ischaemic heart disease. These benefits are attainable with only moderate physical activity, such as a 30-minute daily walk, though a "dose-dependent" relationship exists between physical activity and health benefits: "Some exercise is better than none, and more is better than less". Both the World Health Organisation, and the National Institutes of Health in the USA, for example, recommend that clinicians should counsel all patients to enroll in some programme of regular physical activity tailored to suit their health status and personal life-style.

Adult↗

PubMed1998

Detection of humoral antibodies to Renibacterium salmoninarum in rainbow trout Oncorhynchus mykiss and Atlantic salmon Salmo salar challenged by immersion and in naturally infected populations.

Humoral antibodies to heat-stable antigens of Renibacterium salmoninarum (Rs) were detected by enzyme-linked immunosorbent assay (ELISA) in rainbow trout Oncorhynchus mykiss and in Atlantic salmon Salmo salar challenged by immersion. A slow antibody response was found: 3% (1/30) was positive 4 wk after immersion and 72% (26/36) was positive after 8 wk. All 30 fish sampled after 4 wk were found to be infected, as determined by bacterial culture and/or the presence of soluble antigens in the kidney. At 6, 8 and 12 wk after immersion the proportion of positives indicated by ELISA was 58%. The Rs infection was detected by cultivation in 36% of sampled fish collected on the same occasion. Elevated antibody titres to Rs were detected in samples from both Atlantic salmon (59% in 1 farm) and from rainbow trout (20% in 1 of 5 sampled farms) in naturally exposed populations all of which classified positive for bacterial kidney disease (BKD). Elevated antibody titres were detected among sampled fish from populations of rainbow trout and salmon with clinical BKD. Samples collected from farm populations of rainbow trout, salmon and brown trout Salmo trutta, exposed to Rs but without clinical BKD, were negative in the ELISA, although Rs bacteria or soluble antigens were detected at the same sampling. The antibody ELISA method cannot be recommended for general fish health monitoring purposes, but may be a valuable tool for monitoring the disease progression during controlled experiments.

Actinobacteria↗

PubMed1998

Determinants of self-reported neck-shoulder and low back symptoms in a general population.

STUDY DESIGN: A combined cross-sectional and longitudinal design. OBJECTIVES: To investigate relation between, on one hand, self-reported neck-shoulder symptoms and, on the other hand, low back symptoms and self-reported work-related physical load, psychosocial factors, and individual characteristics and to study the influence of physical capacity in adolescence on neck-shoulder and low back symptoms in adulthood. SUMMARY OF BACKGROUND DATA: Heavy physical work and exposure to vibration constitute risk factors for low back problems, and repetitive and static work are risk factors for neck-shoulder symptoms in many jobs. The interplay between individual factors and work-related psychosocial and physical exposure, however, is not well documented. This study addresses effects of adolescent capacity on this interplay in a general population. METHODS: A random sample of 425 Swedish students was investigated when the students were 16 years and 34 years of age. Sixty-five percent participated in both examinations; only those who worked > or = 16 hours/week at the follow-up period, 148 men and 90 women, were included in these analyses. Data about musculoskeletal symptoms, work, and sociodemographic and individual characteristics were collected at the age of 34 years; physical performance data were collected at the ages of 16 years and 34 years. RESULTS: Among the men, self-employment and worry were associated with neck-shoulder symptoms; among the women, monotonous work and high decision latitude were associated with neck-shoulder symptoms. Low back problems were related to monotonous work among men and women and to exposure to vibration among men. Performance in certain fitness tests at the ages of 16 years and 34 years was negatively associated with musculoskeletal symptoms. CONCLUSIONS: The inverse relationships between performance at the age of 16 years and adult musculoskeletal symptoms may imply benefits of early fitness training.

Adolescent↗

PubMed1998

Substrate availability limits human skeletal muscle oxidative ATP regeneration at the onset of ischemic exercise.

We have demonstrated previously that dichloroacetate can attenuate skeletal muscle fatigue by up to 35% in a canine model of peripheral ischemia (Timmons, J.A., S.M. Poucher, D. Constantin-Teodosiu, V. Worrall, I.A. Macdonald, and P.L. Greenhaff. 1996. J. Clin. Invest. 97:879-883). This was thought to be a consequence of dichloroacetate increasing acetyl group availability early during contraction. In this study we characterized the metabolic effects of dichloroacetate in a human model of peripheral muscle ischemia. On two separate occasions (control-saline or dichloroacetate infusion), nine subjects performed 8 min of single-leg knee extension exercise at an intensity aimed at achieving volitional exhaustion in approximately 8 min. During exercise each subject's lower limbs were exposed to 50 mmHg of positive pressure, which reduces blood flow by approximately 20%. Dichloroacetate increased resting muscle pyruvate dehydrogenase complex activation status by threefold and elevated acetylcarnitine concentration by fivefold. After 3 min of exercise, phosphocreatine degradation and lactate accumulation were both reduced by approximately 50% after dichloroacetate pretreatment, when compared with control conditions. However, after 8 min of exercise no differences existed between treatments. Therefore, it would appear that dichloroacetate can delay the accumulation of metabolites which lead to the development of skeletal muscle fatigue during ischemia but does not alter the metabolic profile when a maximal effort is approached.

Acetylcarnitine↗

PubMed1998

Partial purification and characterization of ornithine carbamoyl transferase (OCT) from the cyanobacterium nostoc sp. Strain PCC 73102

Ornithine carbamoyl transferase (OCT) catalyzes the formation of citrulline and orthophosphate from ornithine and carbamoyl phosphate. We have partially purified OCT from the filamentous cyanobacterium Nostoc sp. strain PCC 73102, using ammonium sulfate precipitation (35-55%), a gel-filtration column (Sephacryl S-200), followed by an affinity column (Sepharose-6B-PALO). The partially purified OCT was analyzed on native-PAGE and shown to be an active enzyme with an estimated molecular weight of approximately 80 kDa. The isoelectric point was determined to be about 6.2. Varying the ornithine concentration resulted in a hyperbolic response of the reaction velocity at lower concentrations. Ornithine concentrations above 2 mM inhibited the enzyme. A hyperbolic response of the OCT reaction was observed when increasing the carbamoyl phosphate concentration. From a double reciprocal plot, a saturation concentration of 0.8 mM and a Vmax of 0.4 U/mg may be calculated. None of the tested compounds (argininosuccinate, arginine, aspartic acid, urea) had any significant positive effect on the in vitro activity of the partially purified OCT. Moreover, at concentrations higher than 10 mM, all tested compounds had an inhibitory effect.

Journal Article↗

PubMed1998

Effect of restricted blood flow on exercise-induced hormone changes in healthy men.

To test the influence of the accumulation of metabolites on exercise-induced hormone responses, plasma concentrations of cortisol, growth hormone (GH), insulin, testosterone, thyrotropin (TSH), free thyroxine (fT4) and triiodothyronine (T3) were compared during exercise performed under normal conditions (control) and under conditions of restricted blood flow of exercising leg muscles (ischaemia) in nine healthy young men. Blood supply was reduced by 15%-20% by the application of 50 mmHg external pressure over the exercising leg. During 45-min cycling exercise during ischaemia the increase in GH concentration was twice as large as under normal conditions. Despite the below-threshold exercise intensity for activation of the pituitary-adrenocortical system under normal exercise conditions ischaemic exercise elicited cortisol and T3 responses (concentration increases of 83% and 9.5%, respectively). Ischaemic exercise attenuated the decrease of plasma insulin concentration found under normal conditions. The concentrations of testosterone, TSH and fT4 were not changed significantly during exercise performed in either condition. The results support the suggested essential role of muscle metaboreceptors in the control of hormone responses during muscle activity.

Adolescent↗

PubMed1998

Quality assurance in clinical perfusion.

OBJECTIVE: To investigate the properties and usefulness of prospective routine registration of incidents related to cardiopulmonary bypass and its clinical significance as a quality assurance instrument. METHODS: Incidents or deviations from the normal course observed during cardiopulmonary bypass procedures were registered in a computer database. Each incident was classified according to 14 pre-defined categories. The cause of each incident was evaluated, as well as patient outcome. Incidents leading to permanent or temporary injury were denoted accidents. The general- and category-related incidence rate was calculated for the observation period 1989-1997 encompassing 6918 cardiopulmonary bypass procedures. RESULTS: The general incidence rate varied between 4.5-7.6% per year during the registration period. Most incidents (57%) occurred during established, or start of, cardiopulmonary bypass, whereas the remaining proportion of incidents were detected either before (27%) or when terminating (16%). The most common category of incidents was oxygenator failure (1.6%), followed by mechanical (1.4%) and surgical (1.2%) incidents. Accidents and fatal outcomes occurred in 0.03% of the cases. CONCLUSIONS: Routine registration of incidents yields a clinically attractive instrument of controlling safety aspects and quality measures in cardiopulmonary bypass. The observed incidence rates are somewhat higher than previously reported, probably primarily related to the methodology implemented in this study.

Accidents↗

PubMed1998

Exercise-based rehabilitation improves skeletal muscle capacity, exercise tolerance, and quality of life in both women and men with chronic heart failure.

BACKGROUND: Data of training effects in chronic heart failure patients are based on findings in men. The purpose of this study was to compare the effects of skeletal muscle endurance training between men and women with chronic heart failure. METHODS AND RESULTS: Twelve consecutive men (mean [+/- SD] age 58 +/- 9 years, left ventricular ejection fraction 29 +/- 9%) and 12 women (60 +/- 10 years, left ventricular ejection fraction 28 +/- 7%) with moderate, chronic heart failure stratified according to age and inclusion criteria were investigated at baseline and after 8 weeks of knee extensor endurance training. The activity of skeletal muscle citrate synthase and resting heart rate were similar in men and women at baseline and with training improved (P < .0001) similarly in both genders. Peak work rate (P < .0001), peak oxygen uptake (P < .001) and muscle strength (P < .05) at baseline were higher in men than in women. Training improved peak work rate (P < .0001) and muscle strength (P < .0001) similarly in both genders, while improvement in peak oxygen uptake was better in women (P < .001). The distance ambulated during 6 minutes was similar in both genders at baseline and increased after training more in men (P < .004). The overall and physical Sickness Impact Profile indicated similarly reduced health-related quality of life in men and women, while worse psychosocial quality of life was observed in men (P < .05). Both genders improved after exercise training in the overall, physical, and psychosocial Sickness Impact Profile (P < .01). CONCLUSIONS: Exercise-based rehabilitation improves skeletal muscle capacity, exercise tolerance, and the health-related quality of life in women as well as in men with moderate, chronic heart failure.

Aged↗

PubMed1998

Prediction of physical fitness and physical activity level in adulthood by physical performance and physical activity in adolescence--an 18-year follow-up study.

The aim of the study was to investigate relationships between physical fitness and self-reported physical activity in adulthood and to what extent the level of physical fitness and leisure-time physical activity in adulthood can be explained by anthropometric measures, physical performance, physical activity, attitudes to sports activities and socio-demographic characteristics at the age of 16. A group of 157 men and 121 women was tested at the ages of 16 and 34 by means of questionnaires and fitness tests. Physically active men and women had higher estimated VO2 max and performed better in curl ups and bench press than those who were inactive. Performance in physical tests, height, weight and physical activity at the age of 16 contributed best to explain adult physical performance and physical activity. The magnitude of explanation varied between 10% (9-min run test) and 56% (bench press test); it was in general lower in the men than in the women. The various fitness tests and physical activity were explained by different predictors and the predictors also differed between men and women. The findings about attitudes to sports and socio-demographic factors at a young age that influence adult physical activity habits and fitness are very complex and further research is required to identify specific inactivity risks.

Adolescent↗

PubMed1998

Muscle acetyl group availability is a major determinant of oxygen deficit in humans during submaximal exercise.

The delay in skeletal muscle mitochondrial ATP production at the onset of exercise is thought to be a function of a limited oxygen supply. The delay, termed the oxygen deficit, can be quantified by assessing the above baseline oxygen consumption during the first few minutes of recovery from exercise. During submaximal exercise, the oxygen deficit is reflected by the extent of muscle phosphocreatine (PCr) breakdown. In the present study, nine male subjects performed 8 min of submaximal, single leg knee extension exercise after saline (Control) and dichloroacetate (DCA) infusion on two separate occasions. Administration of DCA increased resting skeletal muscle pyruvate dehydrogenase complex activation status threefold (Control = 0.4 +/- 0.1 vs. DCA = 1.3 +/- 0.1 mmol acetyl-CoA.min-1.kg wet muscle-1 at 37 degrees C, P < 0.01) and elevated acetylcarnitine concentration fivefold (Control = 2.2 +/- 0.5 vs. DCA = 10.9 +/- 1.2 mmol/kg dry mass, P < 0.01). During exercise, PCr degradation was reduced by approximately 50% after DCA (Control = 33.2 +/- 7.1 vs. DCA = 18.4 +/- 7.1 mmol/kg dry mass, P < 0.05). It would appear, therefore, that in humans acetyl group availability is a major determinant of the rate of increase in mitochondrial respiration at the onset of exercise and hence the oxygen deficit.

Acetylation↗

PubMed1997

Skeletal muscle endurance training improves peripheral oxidative capacity, exercise tolerance, and health-related quality of life in women with chronic congestive heart failure secondary to either ischemic cardiomyopathy or idiopathic dilated cardiomyopathy.

Despite reported benefits of exercise training in men with chronic congestive heart failure (CHF) and in both men and women with coronary artery disease, the effects of training in women with CHF have not been throughly investigated. Therefore, 16 women (62 +/- 10 years [mean +/- SD]) with stable, moderate, chronic CHF (left ventricular ejection fraction 28 +/- 8%) were studied in a randomized crossover trial with 8 weeks of knee extensor endurance training and 8 weeks of nontraining. The effects of the exercise-based rehabilitation were assessed in skeletal muscle metabolic capacity, exercise tolerance, and quality of life. The compliance rate in training was 98% and no adverse events occurred during the study period. Training increased the activity of citrate synthase (44%, p <0.0001) and lactate dehydrogenase (23%, p <0.002) in the trained muscles, and an improved oxidative capacity in relation to the glycolytic capacity (23%, p <0.002) was found. Peak oxygen uptake (14%, p <0.0005) and peak work rate (43%, p <0.0001) during incremental exercise increased, and blood lactate concentration during standardized submaximal exercise and during the recovery phase decreased (17%, p <0.05). The distance ambulated during 6 minutes (p <0.03), and the overall (p <0.01), physical (p <0.05), and psychosocial (p <0.03) health-related quality of life improved. Because the skeletal muscle endurance training improved peripheral oxidative capacity, exercise tolerance, and the health-related quality of life without any adverse events, this mode of training can be recommended for women with chronic heart failure.

Adult↗

PubMed1997

Ornithine cycle in Nostoc PCC 73102: presence of an in vitro functional argininosuccinate lyase.

The presence of argininosuccinate lyase (ASL), an enzyme catalyzing the final step of arginine biosynthesis, was demonstrated in the heterocystous cyanobacterium Nostoc PCC 73102 by measuring in vitro enzyme activity and by visualization of ASL in native protein gels. Activity staining of a native PAGE gel revealed one ASL-dependent band with a molecular mass of about 240 kDa. A colorimetric assay for ASL based on the measurement of urea produced from arginine in the presence of an excess of arginase was further used to analyze the cyanobacterial ASL. The in vitro ASL activity was highest in cells in exponential growth phase and decreased significantly during the stationary phase of growth, ranging from 4.4 to 0.8 nmol of product formed (mg protein)-1 min-1. Including arginine, citrulline or ornithine in the growth medium resulted in no significant change in the ASL activities, indicating that Nostoc PCC 73102 ASL is not regulated by metabolites of the ornithine cycle.

Argininosuccinate Lyase↗

PubMed1997

Clinical effects of the heparin coated surface in cardiopulmonary bypass.

OBJECTIVE: In a randomised study of 120 patients, undergoing primary operation for coronary heart decease, two groups were investigated as regards to the effects of heparin coated cardiopulmonary bypass on brain function parameters and general clinical outcome. The study group (n = 56) was perfused using an extra-corporeal circuit treated with covalent bonded heparin; the control group (n = 59) used an identical set-up without heparin treatment. Systemic heparin doses were calculated to achieve ACT levels of 250 and 500 s, respectively. Postoperative course was evaluated by examining a set of clinically relevant parameters including a detailed registry of postoperative deviations. Brain function was assessed by the biochemical marker S-100 and tests of memory performance. RESULTS: There were several signs of reduced operative trauma in the study group. Hospital stay was reduced by nearly 1 day (P < 0.05). Time on postoperative ventilatory support was approximately 4 h shorter (P = 0.009). Chest drain blood loss was decreased both at 8 (P = 0.01) and 24 h (P = 0.007) postoperatively. Body temperature was lower after surgery and especially on days 2 (P = 0.03) and 3 (P = 0.01). Perioperative creatinine elevation was significantly reduced (P = 0.03). Neurological deviations were fewer (P = 0.01). Brain function assessment revealed reduced plasma levels of S-100 both at termination of cardiopulmonary bypass (P = 0.008) and 7 h later (P = 0.04). However, no remediation of memory impairment could be demonstrated. CONCLUSIONS: Cardiopulmonary bypass with covalent bonded heparin attached to the extra-corporeal circuit in combination with a reduced systemic heparin dose seems to reduce safely and effectively the operative stress to the patient. There were also signs of improved cerebral protection.

Anticoagulants↗

PubMed1997

Improved ventilation and decreased sympathetic stress in chronic heart failure patients following local endurance training with leg muscles.

BACKGROUND: Two-legged knee extensor training activates only about half the muscle mass used in traditional cycle ergometer training. With such an exercise model it is possible to achieve a substantial local training effect in spite of a restricted circulatory capacity. The present study sought to investigate the systemic effects of such local training on ventilation and neurohumoral activity in patients with moderate heart failure. METHODS AND RESULTS: Thirteen male patients with chronic heart failure (age 56 +/- 3 years, EF 28 +/- 3%) performed two-legged knee extensor exercises (about 4 kg of working muscle) for 15 minutes 3 times a week during 8 weeks at 65-75% of peak VO2 of a two-legged kick and were compared to a non-training control group (n = 7, age 62 +/- 3, EF 27 +/- 3%). Before and after the training period VO2, VCO2 and the minute ventilation (1/min) were determined at rest and at submaximal and maximal workloads. Also measured before and after training were two-legged knee extensor peak exercise capacity (W), strength (Nm), a 6-minute walking test (m), quadriceps femoris citrate synthase activity, plasma catecholamines, vasoactive amines and blood lactate during submaximal knee extension exercise, and perceived health-related quality of life. After training, VO2 and VCO2 were reduced at submaximal exercise by 20-30% (P < .01) but were unchanged at peak exercise. With training, the two-legged knee extensor peak exercise capacity increased by 38% (P < .01). The 6-minute walking gait velocity increased by 12% (P < .01) and skeletal muscle citrate synthase activity by 28% (P < .01). Training improved the quality of life (P < .01). After training, VO2 (P < .001), VCO2 (P < .001) and minute ventilation (P < .001) were reduced at the workload corresponding to the maximal workload before training. The ratio minute ventilation/VO2 was reduced (P < .05) after training at the before-training maximal workload. No change was observed in the control group with regard to two-legged peak exercise capacity or peak VO2. Plasma NPY was reduced both at rest and at submaximal exercise by 35% (P < .01), whereas noradrenaline was reduced only during exercise (P < .05). CONCLUSIONS: Local muscle training is effective in stable chronic heart failure and can improve, in addition to exercise capacity and quality of life, the ventilatory response, and decrease the sympathetic stress.

Adult↗

PubMed1997

High proportion of type I fibres in thigh muscle of young dancers.

A previous study showed that adult female dancers have a high percentage of type I fibres in vastus lateralis, similar to that of endurance-trained female runners or female cross-country skiers. It is not known if dancers already at an early age are characterized by a high percentage of type I fibres or develop a high percentage of type I fibres as a consequence of dance training. Furthermore, the muscle fibre composition of male dancers has not previously been studied. Therefore the aim of the study was to analyse skeletal muscle fibre characteristics in 10-year-old and 20-year-old dancers of both sexes. Age-matched boys and girls whose physical activity was average for their age groups served as controls. Muscle biopsies for histochemical analysis were obtained from vastus lateralis using the percutaneous needle technique. The major finding of the present study was that the vastus lateralis of young dancers of both sexes had a higher percentage of type I fibres than that of controls. Moreover, the higher type I percentage was seen not only in 20 year olds, but also in 10 year olds, who had begun their dance training at a professional level only a few weeks earlier. No significant difference in this respect was found between female and male dancers. In conclusion, the muscle fibre type composition in young dancers of both sexes differs from that of the average individual of the same age and is characterized by a high percentage of type I fibres.

Adolescent↗

PubMed1997

The relative safety of an oxygenator.

Analysis of prospectively registered incidents related to cardiopulmonary bypass (CPB) was initiated to establish the incident rate for 10 different oxygenator brands employed over a seven-year period in 5000 clinical perfusions. A general safety index (SI) was defined as the number of recorded incidents in a given series of oxygenators divided by its total number and multiplied by 100. Specific SI was calculated for each of the following categories: high-pressure drop, debris, gas exchange, leakage, material failure and oxygenator change-out. An SI of 0.2 was arbitrarily set as a reference and an acceptable safety level. An estimate of the relative risk for a particular oxygenator brand was compared with the reference by calculating the odd's ratio with a 95% confidence interval. The mean SI was determined to be 1.6, ranging from 0 for the Maxima CBAS and the Cobe CML to 2.92 for the Safe oxygenator. The dominating specific type of incident was HPD with an SI of 0.81 followed by debris, SI = 0.71. A systematic analysis of adverse events in CPB may be used to evaluate and to set standards, a method already employed in the pharmaceutical industry. Our results indicate that oxygenator safety margins may vary between different brands.

Cardiopulmonary Bypass↗

PubMed1997

Muscle characteristics in effort angina before and after CABG.

Seven males with effort angina undertook graded ergometer tests and had muscle biopsies taken from their vastus lateralis muscle before, and three and six months after coronary bypass surgery. Muscle fibre composition (percentage of slow twitch fibres), ubiquinone (vitamin Q), and oxidative and fermentative enzyme activities were determined. After six months, muscle ubiquinone and oxidative enzymes were still depressed, indicating sustained muscle trauma. The only peripheral changes were that muscle lactate dehydrogenase and its skeletal muscle-specific subunits and isozymes were increased 35% to 40% (P < 0.001) three to six months postsurgery. Onset of blood lactate accumulation (2.0 mmol/L), symptom-limited ('maximal') exercise and peak blood lactate increased linearly over time (r = 0.52, P < 0.05; r = 0.63, P < 0.01; and r = 0.76, P < 0.001, respectively). It is suggested that the initial physical performance increase was due to improved circulatory capacity, oxygen delivery and lactate efflux, whereas the increased fermentative capacity ('anaerobic power') first contributed after a lag of three or more months. Whether the muscle histochemical changes reflected a healing process (recovery) is speculative.

Angina Pectoris↗