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Biomedical subjects

E Jansson

Publications and source records attributed to E Jansson.

At least 91 records · Page 5Linked to original sources
PubMed1993

Fast twitch fibres may predict anaerobic performance in both females and males.

The aim of the present study was to compare males and females with similar training backgrounds regarding the relationship between anaerobic performance and muscle characteristics and to test whether any of the analysed expressions of muscle characteristics could predict some of the difference in anaerobic performance between sexes. Subjects performed 30 s all-out sprints on a bicycle ergometer (Wingate test) and needle muscle biopsies were taken at rest. Peak and mean power were respectively 44% and 48% higher in males than in females. Activity of total lactate dehydrogenase (LD) was 33% higher and of M subunit of LD 38% higher in males. Anaerobic performance was directly related to the proportion of type II fibres, the relative M subunit activity or the activity of PFK in both males and females and the higher M subunit activity in males could predict some of the sex difference in anaerobic performance. It is suggested that anaerobic performance is directly related to fast contractile or/and anaerobic metabolic properties of skeletal muscle with no sex difference in this relationship. The difference in anaerobic performance between the sexes may partly be related to the sex difference in anaerobic metabolic properties of skeletal muscle.

Adult↗
PubMed1993

Ventricular adenine nucleotide translocator mRNA is upregulated in dilated cardiomyopathy.

OBJECTIVE: A disturbed energy transfer involving the adenine nucleotide translocator across the inner mitochondrial membrane has been suggested to be one specific pathogenetic mechanism in dilated cardiomyopathy. Pretranslational steady state expression of this protein in dilated cardiomyopathy was investigated. METHODS: Concentrations of adenine nucleotide translocator were quantified by solution hybridisation. The enzyme or protein expressions of citrate synthase, lactate dehydrogenase, and creatine kinase with isozymes were determined. Analysis was performed on specimens from the left and right ventricles from six organ donor hearts, six explanted hearts with dilated cardiomyopathy, two explanted hearts with ischaemic cardiomyopathy, and from papillary muscles from seven patients operated on for mitral regurgitation. RESULTS: The ejection fraction in patients with mitral regurgitation was 50(10)%, significantly higher (p < 0.001) than in patients with dilated cardiomyopathy (23(5))%. In mitral regurgitation and in ischaemic cardiomyopathy left ventricular adenine nucleotide translocator mRNA concentrations did not differ from those in donor hearts. In dilated cardiomyopathy, adenine nucleotide translocator mRNA concentrations were significantly increased (p < 0.001). Upregulation was more pronounced in right ventricular than in left ventricular myocardium (p < 0.01). The lactate dehydrogenase M subunit fraction was increased to a similar degree in dilated cardiomyopathy and in mitral regurgitation (p < 0.05). Citrate synthase activity was significantly decreased only in dilated cardiomyopathy (p < 0.005). On the other hand, the creatine kinase B subunit content was significantly higher in mitral regurgitation than in dilated cardiomyopathy (p < 0.001). CONCLUSIONS: Despite signs of increased anaerobic and depressed oxidative capacities, dilated cardiomyopathy was specifically characterised by pretranslational upregulation of adenine nucleotide translocator.

Adolescent↗
PubMed1993

Increased expression of the lactate dehydrogenase M subunit in myocardial regions with decreased thallium uptake.

OBJECTIVE: In ischaemic heart disease, the heart muscle is subjected to repeated episodes of regional ischaemia or to a constant underperfusion. The purpose of the present investigation was to study the myocardial metabolic adaptation to this stress. METHODS: Eighteen male patients with ischaemic heart disease were studied by biopsies taken from the left ventricular septum during bypass surgery. Citrate synthase, total lactate dehydrogenase and its H and M subunits, coenzyme Q10, and myoglobin were determined in all biopsies. Concentrations of ATP, ADP, and AMP were determined and energy charge calculated in the biopsies from the patients with ischaemic heart disease. Biopsies from the septal region of hearts obtained from brain dead kidney and liver donors were used as reference and preoperative myocardial thallium scintigraphy was performed in the patients with ischaemic heart disease to relate the myocardial biochemical markers to thallium uptake at the biopsy site. RESULTS: Myocardial activities of citrate synthase as well as contents of coenzyme Q10 and myoglobin in patients with ischaemic heart disease were not different from those of the reference group, and no linear relation was found between these three markers on the one hand and thallium uptake on the other. The energy charge was directly related and the M subunit of lactate dehydrogenase inversely related to the thallium uptake. CONCLUSION: The results suggest an absence of adaptation to ischaemia in terms of increased myocardial oxidative capacity and O2 transport and storage capacity. Furthermore, it is indicated that a stressed energy metabolism with increasing severity of ischaemic heart disease enhances anaerobic metabolism and induces a shift in myocardial lactate dehydrogenase subunit fractions.

Adolescent↗
PubMed1993

Muscle fibre types and enzyme activities after training with local leg ischaemia in man.

Eight healthy men performed supine one-legged training on a bicycle ergometer 45 min per leg four times per week for 4 week. The ergometer and lower body were inside a pressure chamber, the opening of which was sealed at the level of the crotch. One leg trained with impeded leg blood flow (I-leg), induced by an increased (50 mmHg) chamber pressure, at the highest tolerable intensity. The contralateral leg trained at the same power under normal pressure (N-leg). Before and after training biopsies were taken from the vastus lateralis of both legs and maximal one-legged exercise tests were executed with both legs. Biopsies were repeated when the subjects had been back to their habitual physical activity for 3 months. Training increased exercise time to exhaustion, but more in the I-leg than in the N-leg. After training, the I-leg had higher activity of citrate synthase (CS), a marker of oxidative capacity, and lower activity of the M-subunit of lactate dehydrogenase isoenzymes. It also had a higher percentage of type-I fibres and a lower percentage of IIB fibres, larger areas of all fibre types and a greater number of capillaries per fibre. It is concluded that ischaemic training changes the muscle metabolic profile in a direction facilitating aerobic metabolism. An altered fibre-type composition may contribute, but is not enough prerequisite for the change.

Adult↗
PubMed1993

Effects of renal failure on skeletal muscle.

In this cross-sectional study, we examined biopsies from the vastus lateralis muscle of 13 predialytic uremic men (mean age 46 +/- 8 years). Their average glomerular filtration rate was 14 +/- 7 ml/min x 1.73 m2 and their maximal exercise capacity, measured by standardized exercise test on a bicycle ergometer, was 184 +/- 45 W (94% of the expected norm). The proportion of type I fibers (type I%) in the uremic group was similar to that of the reference group (42 +/- 11 vs. 41 +/- 8% NS). The proportion of type IIA fibers (type IIA%) in the uremic group was higher than in the reference group (44 +/- 10 compared to 35 +/- 9%, p < 0.05). The proportion of type IIB fibers (type IIB%) was lower than in the reference group (13 +/- 8 vs. 21 +/- 8%, p < 0.05). Type I fiber area was similar to that of the reference group (4,768 +/- 1,033 vs. 4,627 +/- 1,112 microns 2, NS). Type IIA and type IIB fiber areas tended to be smaller than those of the reference group (type IIA fiber area: 4,515 +/- 929 vs. 5,213 +/- 1,288 microns 2, NS; type IIB fiber area: 3,953 +/- 1,066 vs. 4,406 +/- 1,582 microns 2, NS) with a type IIA area/type I area ratio which was significantly lower than in the reference group. Citrate synthase activity was 0.48 +/- 0.08 mu kat/g in the uremic group and 0.50 +/- 0.08 mu kat/g in the reference group, NS.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Therapy-resistant hypertension associated with central obesity, insulin resistance, and large muscle fibre area.

Obesity and an enhanced insulin response to oral glucose tolerance test are associated with therapy resistance in hypertension. In order to explore this association further we studied the insulin sensitivity of subjects with essential hypertension resistant to triple drug therapy (RH), with the euglycemic insulin clamp technique. Well controlled hypertensives, matched for age, gender and body mass index (BMI) served as controls. Male subjects (7 RH and 7 controls) were further investigated by biopsies of Musculus Vastus lateralis since structural conditions in skeletal muscles might have a role in the above association. Irrespective of pre-study drug therapy, therapy-resistant hypertensives had a lower insulin sensitivity index than controls (p < 0.05). In spite of the BMI-match waist/hip ratio (WHR) in the RH males tended to be higher (p < 0.07). Insulin clearance tended to be lower in RH subjects (p = 0.09). BMI correlated with a reduced muscular capillary density (r = -0.77, p < 0.01). The average cross-sectional muscle fibre area was larger in RH subjects (p < 0.05). The mean muscle fibre area correlated with basal serum insulin (r = 0.63; p < 0.05). Rarefaction of the muscular capillary bed appears to be related to obesity. Larger muscle fibres might be an effect of the growth factor properties of insulin and could possibly correspond to hypertrophy of smooth muscle in the resistance vessels. This factor might contribute to the association of hyperinsulinemia and hypertension and attenuate the response to antihypertensive therapy.

Adult↗
PubMed1992

Increase in functional activity rather than in amount of Gi-alpha in failing human heart with dilated cardiomyopathy.

OBJECTIVE: The aim was to investigate whether or not increased pertussis toxin catalysed ADP ribosylation correlates with increased amount of Gi-alpha in failing human heart. DESIGN: Antisera raised against unique synthetic peptides corresponding to alpha subunits of Gs and Gi 1-3 were used in immunoblotting and ELISA to determine amounts of various G proteins. Adenylyl cyclase activity, beta adrenoceptors, and muscarinic receptors were then measured in cardiomyopathic hearts (n = 6) obtained at transplant in order to study whether or not an altered expression of G proteins has relevance to the integrity and function of the receptor--adenylyl cyclase system. Six non-failing control hearts were also studied. RESULTS: No significant differences in the peptide equivalent amounts of either Gs or Gi were found in the failing human heart as compared to the non-failing heart. However, functional activity of Gi was shown to increase significantly since there was a decrease in basal (57%), isoprenaline stimulated (60%), and guanyliminodiphosphate stimulated (52%) adenylyl cyclase activity. In contrast the density of beta adrenoceptors was markedly decreased (51%) in failing human heart in comparison to non-failing hearts. Neither the density nor the affinity of muscarinic receptors changed in the failing human heart. CONCLUSION: These results suggest that in the failing human heart, there is an increase in functional activity rather than in amount of Gi, and an important part of functional expression of Gi-alpha may be regulated at the post-translational level.

Adenylyl Cyclases↗
PubMed1992

Serological responses to mycoplasmas in HIV-infected and non-infected individuals.

OBJECTIVE: To assess the frequency of mycoplasma infections in HIV-antibody-positive and -negative individuals by studying the serological responses against mycoplasmas, especially Mycoplasma fermentans and M. pirum. DESIGN: An enzyme-linked immunosorbent assay (ELISA) was used to measure immunoglobulin G (IgG) class antibody concentrations against six mycoplasma species in sera of HIV-positive and HIV-negative individuals. METHODS: Serum samples were obtained from 30 HIV-positive individuals (10 asymptomatics, 10 with lymphadenopathy syndrome and 10 with AIDS), 10 HIV-negative partners of HIV-positive individuals and 40 HIV-negative blood donors. Antibodies to M. fermentans strains incognitus and PG18, M. pirum, M. genitalium, M. pneumoniae and M. hominis were assessed by immunoblot or ELISA. Absorbance values were taken as a semiquantitative measurement for antibody concentration and an arbitrary cut-off value (0.8) was set to establish seroprevalence. RESULTS: There was no significant difference in the mean IgG concentrations of any of the six mycoplasmas between HIV-positive and HIV-negative groups. Antibody concentrations were also similar in different clinical phases of HIV infection. Antibody concentrations to different mycoplasma strains were compared with each other to reveal eventual cross-reactions caused by shared antigens; the strongest correlation (r = 0.836) was found between M. fermentans strains incognitus and M. pirum antibody concentrations. The correlation between M. fermentans strains incognitus and PG18 was also significant but weaker (r = 0.522). No shared antigens between M. fermentans strain incognitus and M. pirum were demonstrated by immunoblot. CONCLUSIONS: Antibodies against M. fermentans type strain PG18, strain incognitus and against M. pirum are detected infrequently and their presence does not correlate with HIV infection per se or with the clinical stage of HIV infection.

Antibodies, Bacterial↗
PubMed1992

Changes in muscle fibre type from adolescence to adulthood in women and men.

Age-related changes in muscle fibre characteristics have been presented in cross-sectional studies previously. The aim of the present study was to investigate longitudinally whether the muscle fibre type composition and muscle fibre area change from adolescence to adulthood. Fifty-five men and 28 women were studied at the age of 16 and again at the age of 27. Biopsies were taken from the vastus lateralis muscle and analysed for fibre types (I, IIA, IIB, IIC) and fibre areas. Different development of fibre type composition with increased age were seen in women and men: the type I percentage tended to increase in the women (51 +/- 9 to 55 +/- 12) and decrease significantly in the men (55 +/- 12 to 48 +/- 13). The fibre areas remained unchanged in both sexes. It is suggested that there is a sex-related fibre adaptation to increased age.

Adolescent↗
PubMed1991

Left ventricular beta 1 and beta 2 adrenoceptor mRNA expression in normal and volume overloaded human heart.

STUDY OBJECTIVE: The aim was to determine gene expressions of beta 1 and beta 2 adrenoceptor subtypes (BAR-1, BAR-2) in normal and volume overloaded human heart. DESIGN: Tissue mRNA levels were determined by excess solution hybridisation using 35S-UTP labelled BAR-1 and BAR-2 cRNA probes. MATERIAL: Atrium, right and left ventricular subendocardium, and papillary muscle from donor hearts and papillary muscle from patients operated for mitral stenosis and mitral regurgitation were studied. MEASUREMENTS AND MAIN RESULTS: The basal levels of myocardial BAR-1 and BAR-2 mRNA expression were similar to the levels in human adipose tissue that have been reported previously from our laboratory (10-15 amol mRNA.micrograms-1 total nucleic acids). No differences in BAR-1 and BAR-2 mRNA expression were observed between various parts of the normal heart. In papillary muscle, BAR-1 and BAR-2 mRNA levels were 8.8 (SEM 5.1) and 10.2(6.6) amol.micrograms-1 total nucleic acids, respectively. Furthermore, no differences in BAR mRNA expression were observed between myocardium subjected to mitral stenosis as compared to normal myocardium. On the other hand, patients with mitral regurgitation expressed significantly lower levels of both BAR-1 and BAR-2 mRNA, at 4.8(1.0) (p less than 0.05) and 2.6(1.1) (p less than 0.001) amol.micrograms-1 total nucleic acids, respectively. The ratio BAR-1/BAR-2 mRNA was higher (p less than 0.01) in mitral regurgitation than in the normal heart. CONCLUSIONS: Myocardium from different parts of the normal human heart, where different pressure work is generated, express similar levels of BAR-1 and BAR-2 mRNA. With volume load a significant decrease in BAR mRNA levels was observed, which was more marked for BAR-2 mRNA. This difference in specific mRNA levels in patients with mitral regurgitation indicates an independent regulation of the expression of these two receptor subtypes.

Adolescent↗
PubMed1991

Dynamics of creatine kinase shuttle enzymes in the human heart.

Myocardial cytoplasmic creatine kinase subunits M and B, mitochondrial CK (CKMIT), and citrate synthase (CS) were determined in 10 locations of the normal human heart (n = 8) and in papillary muscles of patients operated on for mitral regurgitation (n = 6). Compared to atrial biopsies, septal and left ventricular biopsies showed higher activities for CS (P less than 0.0001), total CK (P less than 0.05) and CKMIT (P less than 0.0001). CKM was evenly distributed. CKB activity in the right septum and left ventricular locations were 0.5-1% of total CK and 4-5 times lower than those of the atria and the right ventricular free wall. Activities of CS, CKB and CKMIT in right septal biopsies did not differ from those in left ventricular locations. The activities of CS, total CK, and CKM in papillary muscle from patients operated on for mitral regurgitation did not differ from that of healthy papillary muscle. CKMIT was about 40% lower (P less than 0.02), whereas CKB was 15-20 times higher (P less than 0.0001) than in the healthy heart. In conclusion, adaptations within the creatine kinase system occur in the human heart in health and disease. Small amounts of CKB in the normal left ventricle, as opposed to the right ventricular free wall, might be related to differences in myocardial perfusion during the cardiac cycle. In disease, a decreased CKMIT and dramatically increased CKB may indicate a stressed intracellular energy transfer. CK enzyme activities in right septal biopsy specimens may be used as an indication of metabolic stress on the myocardium of the left ventricle.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Skeletal muscle depressed calcium and phosphofructokinase in chronic heart failure are upregulated by captopril--a double-blind, placebo-controlled study.

The effects of the angiotensin converting enzyme inhibitor captopril, after treatment for 5-6 weeks with 25 mg t.i.d., were studied in 12 patients with stable moderate heart failure. Five patients received placebo treatment, and the two groups were comparable at baseline. Angiotensin II levels decreased in response to captopril therapy. Skeletal muscle potassium, magnesium and chloride levels did not differ from reference values. Calcium was subnormal (P less than 0.0001), but increased to the reference range during captopril treatment. Phosphofructokinase, a rate-limiting glycolytic enzyme, was in the lower reference range and increased (P less than 0.04) in response to captopril therapy. In conclusion, stable moderate heart failure is associated with low levels of skeletal muscle calcium and phosphofructokinase activity, these metabolic changes tending to return to normal levels with captopril treatment.

Aged↗
PubMed1991

Small accumulation of inosine monophosphate (IMP) despite high lactate levels in latissimus dorsi during transplantation.

The effects of prolonged ischaemia and subsequent reperfusion during and after reconstructive microsurgery on energy metabolism were studied. Repeated skeletal muscle biopsies were taken and analysed for high energy phosphates and their degradation products by high performance liquid chromatography and for lactate by a fluorometric procedure. Moderate changes in adenine nucleotides occurred during the first 4 h of ischaemia. After 6 h of ischaemia, when the creatine phosphate store was almost depleted and the lactate level had increased to 111 mmol kg-1 dry muscle, ATP content decreased and inosine monophosphate started to accumulate. The inosine monophosphate accumulation was however small, in spite of a high lactate level, which suggests that the increase in H+ associated with lactate formation is not important for the activation of AMP-deaminase during the present conditions. In spite of the accelerating metabolic deterioration during the later period of ischaemia, the reperfusion of the muscle resulted in a rapid normalization of all the studied metabolites, thereby indicating a rapid restoration of the muscle energy stores.

AMP Deaminase↗
PubMed1991

Does chronic hypoxaemia induce transformations of fibre types?

The study comprised nine patients with chronic obstructive lung disease. Quadriceps muscle biopsies were studied with respect to fibre type composition before and after haemodilution that brought haemoglobin (Hb) to within normal limits. Ten days elapsed between the two biopsy occasions. The arterial oxygen tension (PaO2) and saturation (SaO2) were depressed to 8.4 +/- 2.0 kPa and 89 +/- 11% in the patients with chronic obstructive lung disease and increased to 9.2 +/- 2.1 and 91 +/- 8% with haemodilation. The type II fibre proportion was 71 +/- 12% before haemodilation and significantly higher than normal (reference group, see Aniansson et al. 1981). Following haemodilation the proportion of type II fibres decreased significantly to 60 +/- 14%. The proportion of type II fibres was directly related to the haemoglobin content before, but not after, haemodilation and was inversely related to PaO2 and SaO2 both before and after haemodilation. In conclusion, hypoxaemia may be a factor underlying the high proportion of type II fibres found in patients with chronic obstructive lung disease.

Aged↗