[Testing of hearing aids--the perfect apparatus cannot be found].
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Correction of Hearing Impairment↗
Biomedical subjects
E Jansson
Publications and source records attributed to E Jansson.
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↗
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↗
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↗
[Renewed occurrence of Mycoplasma].
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AIDS-Related Opportunistic Infections↗
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↗
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↗
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↗
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↗
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↗
Mycoplasmas and human arthritis.
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Arthritis↗
Myocardial lactate dehydrogenase and its isoenzyme activities in transplanted human hearts.
Lactate dehydrogenase and its heart (H) and muscle (M) subunit activities were studied in right ventricular endomyocardial biopsies from eight transplanted human hearts and compared with five chronically failing hearts and six normal human hearts from brain-dead liver/kidney donors. Of the 17 transplant biopsies (taken 5-95 weeks postoperatively), only two showed histologic signs of chronic rejection: They were excluded from the group analysis. A higher proportion of the M subunit of lactate dehydrogenase (M%) was found in the transplanted and the chronically failing hearts than in the normal hearts, presumably reflecting increased myocardial anaerobic glycolytic stress. In the early post-transplantation period, M% was higher in the transplanted than in the chronically failing hearts. Thereafter M% gradually fell, but had not reached normal levels 1-2 years after transplantation. During that time it was similar to the values in the chronic-failure hearts. In the two biopsies with chronic rejection, M% was nearly twice as high as in contemporaneous biopsies showing mild or no rejection. Monitoring of enzymatic adaptation from endomyocardial biopsies may be of clinical interest.
Adolescent↗
Discrepancy between estimated energy intake and requirement in female dancers.
Dietary intake of energy, protein, fat and carbohydrates in female dance students compared to female music students was estimated by a dietary history method. Energy requirement was estimated from body weight and physical activity both by a standard formula and from the measured work intensity during dance training. Meal patterns showed significant differences in four types of meals on week-days and in one type on weekends. The intake of protein, fat and carbohydrates in absolute amounts and the percentage of energy derived from protein were not significantly different between the two groups. The fraction of energy derived from carbohydrates was higher and that from fat was lower in the dancers than in the musicians. Energy intake was of similar magnitude for the dancers and the musicians (8.3 +/- 1.9 MJ vs. 8.3 +/- 1.7 MJ), while the estimated energy requirement was greater for the dancers (10.3 +/- 0.7 MJ vs. 8.9 +/- 0.4 MJ). The reason for the apparent discrepancy between energy intake and energy requirement of approximately 2 MJ in the dancers is not obvious. The energy intake may have been underestimated. Alternatively, the energy requirement may have been overestimated. The resting metabolic rate may have been depressed by years of low energy intake. In addition, as suggested by some authors, training as such may lower the resting metabolic rate as well as the diet-induced thermogenesis.
Adult↗
Myoglobin and enzyme adaptations in erector spinae muscles in thoracal scoliosis.
Bilateral biopsies from the erector spinae muscles were taken during surgery from 10 females and two males (mean age 14, range 13-17 years) with thoracal scoliosis for 6 years (range 2-11 years). The biopsies were analysed for myoglobin (MYO), citrate synthase (CS) and creatine kinase MB (CK-MB). The severity of scioliosis was estimated by Cobb's angle, the greater the angle the more severe the disease. The convex/concave side ratio (CVX/CCV) was for CS 1.3 +/- 0.4 (P less than 0.01), CK 0.9 +/- 0.1 (P less than 0.05), CK-MB 1.6 +/- 0.4 (P less than 0.01) and for MYO 1.1 +/- 0.2 (P greater than 0.05). No significant correlations were found between the CVX/CCV for CS, CK or CK-MB on the one hand and the Cobb's angle on the other. The CVX/CCV for MYO was, however, directly related to the angle (r = 0.80, P less than 0.01). For the lower range of angles (less than or equal to 59 degrees) the CVX/CCV for MYO was below unity (0.88, P greater than 0.05) and for the larger angles (greater than 59 degrees) above unity (1.23, P less than 0.05). In conclusion, a dissociation in the adaptive response of m. erector spinae in scoliosis between mitochondrial enzyme and myoglobin content was demonstrated.
Adolescent↗
Decrease in myoglobin and enzyme contents with haemodilution in non-hypoxaemic polycythaemic patients.
Quadriceps muscle biopsies from five patients with primary polycythaemia and four patients with non-primary polycythaemia, all with normal respiratory functions, were studied before and after normalization of haemoglobin and erythrocyte volume fraction by haemodilution or venaesectio. Since similar results were obtained from both groups of patients data were pooled. After normalization of the erythrocyte volume fraction myoglobin decreased by 19 +/- 16%, P less than 0.01, the activity of creatine kinase and citrate synthase by 12 +/- 8 and 14 +/- 18%, P less than 0.05, respectively. The decrease in myoglobin content was related to the decrease in haemoglobin concentration (r = 0.77, P less than 0.01). In conclusion, these data suggest that in non-hypoxaemic polycythaemia skeletal muscle shows adaptations indicative of an impaired oxygenation and a metabolic stress, adaptations that are reversed by haemodilution.
Aged↗
Relationship of recovery from intensive exercise to the oxidative potential of skeletal muscle.
This study examined if there was a relationship between the aerobic-oxidative potential of skeletal muscle and the metabolic and force recovery after intense exercise. Eleven male subjects performed three bouts of unilateral knee extensions using an isokinetic device. Sixty seconds of rest separated bouts. Muscle biopsies were taken from the vastus lateralis prior to exercise, immediately after bout 2 and before bout 3. Samples were analysed for adenosine triphosphate (ATP), adenosine diphosphate (ADP), inosine monophosphate (IMP), creatine phosphate (CP) and lactate contents and citrate synthase (CS) activity. Peak torque at the end of bout 2 was 45% of initial peak torque of bout 1 (IPT1). With recovery, initial peak torque of bout 3 (IPT3) was 81% of IPT1. Peak torque after recovery (IPT3/IPT1) was related to CS activity (r = 0.69). ATP, CP and ATP/ADP decreased with exercise. ADP, IMP and lactate increased. With recovery, ATP and CP remained depressed. IMP and lactate remained elevated. ATP/ADP and ADP returned towards 'normal', but only the latter attained resting levels. When analysing the individual responses the following correlations were found. After recovery, ATP/ADP (r = 0.57), ATP/ADP relative to rest (r = 0.71), lactate (r = -0.62), CP (r = 0.75) and CP relative to rest (r = 0.83) were related to CS activity. The changes in lactate (r = -0.76) and CP (r = 0.79) during recovery (bout 3-bout 2) were also related to CS activity. The results suggest that the recovery of force and the 'normalization' of metabolite contents after short-term, intense exercise are dependent on the aerobic-oxidative potential of skeletal muscle.(ABSTRACT TRUNCATED AT 250 WORDS)
Adenosine Diphosphate↗
Increase in the proportion of fast-twitch muscle fibres by sprint training in males.
Fifteen male physical education students were studied. The subjects trained for 4-6 weeks, 2-3 days per week, on a mechanically braked bicycle ergometer. A training session consisted of repeated 30-s 'all-out' sprints on a Wingate bicycle ergometer, on which the brake band of the flywheel was loaded with 75 g kg-1 body wt, with rest periods of 15-20 min between consecutive sprints. Thigh muscle biopsies were taken before and after the training period and were analysed for fibre types using a myofibrillar ATPase stain. The proportion of type I fibres decreased from 57 to 48% (P less than 0.05) and type IIA fibres increased from 32 to 38% (P less than 0.05). This study indicates that it is possible to achieve a fibre type transformation with high-intensity training. The effect of two-legged 'sprint' training on muscle fibre type composition may be related to a changed pattern of muscle fibre activation (e.g. an increased stimulation frequency). A change in fibre activation frequency may induce an increased synthesis of type II fibre myosin (fast myosin). Hormonal influences such as enhanced adrenergic stimulation of the muscle fibres cannot be excluded as a contributing factor, however.
Adenosine Triphosphatases↗