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Biomedical subjects

M Schaufelberger

Publications and source records attributed to M Schaufelberger.

15 recordsLinked to original sources
PubMed2001

[Better treatment of heart failure by measurements of natriuretic peptides. There are still remaining problems when it comes to the interpretation of measurement levels].

The heart is increasingly being recognised as a major endocrine organ involved in haemodynamic homeostasis. Natriuretic peptides, i.e. atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), affect renal, adrenal and central nervous system functions as well as vessel tonus and permeability thus causing decreased preload and afterload. Natriuretic peptides, BNP in particular, are independent risk factors for morbidity and mortality. They also have high negative predictive values for cardiac insufficiency indicating high diagnostic sensitivity for heart failure in outpatient practice. Monitoring of therapy for heart failure may be improved if BNP measurement is used in conjunction with clinical assessment. However, several problems remain to be solved, such as optimal decision limits in relation to sex and age for the assessment of heart failure.

Atrial Natriuretic Factor↗
PubMed2001

Skeletal muscle characteristics, muscle strength and thigh muscle area in patients before and after cardiac transplantation.

BACKGROUND: Patients with chronic heart failure demonstrate several skeletal muscle abnormalities. The underlying mechanisms are unclear. After cardiac transplantation, cardiac function is restored, but exercise capacity is still impaired. AIM: To evaluate the influence of cardiac transplantation on skeletal muscle fibre composition, fibre area and capillarization as well as muscle enzymes, lactate, thigh muscle area and strength. METHODS: Ten patients were longitudinally investigated before, 1-3 and 6-9 months after transplantation. Ten healthy individuals served as controls. A biopsy from the lateral vastus muscle was obtained and the thigh muscle area was measured with computed tomography. Muscle strength in the knee extensors and exercise capacity were also evaluated. RESULTS: Muscle lactate was elevated in patients vs. controls (3.6+/-3.0 vs. 1.5+/-0.7 mmol/kg wet wt., P=0.037), and decreased to normal (1.4+/-0.3 mmol/kg wet wt., P=0.038) after transplantation. Citrate synthase activity was decreased in patients (5.6+/-1.5 micromol/g wet wt./min) vs. controls (8.1+/-1.6 micromol/g wet wt./min, P=0.0018), and did not change post transplantation. Patients had decreased number of capillaries in contact with each fibre vs. controls (2.6+/-0.5 vs. 3.5+/-1.0, P=0.039) which persisted post transplantation. Exercise capacity increased after transplantation (74+/-22 vs. 118+/-26 W, P=0.0002), whereas muscle strength did not improve significantly. CONCLUSION: The persisting intrinsic abnormalities in skeletal muscle after cardiac transplantation may contribute to the impaired exercise capacity observed in cardiac transplant recipients.

Case-Control Studies↗
PubMed1998

Angiotensin-converting enzyme gene expression in skeletal muscle in patients with chronic heart failure.

BACKGROUND: Skeletal muscle factors may influence functional limitation in patients with heart failure. The renin-angiotensin system is activated in chronic heart failure. Treatment with angiotensin-converting enzyme (ACE) inhibitors improve symptoms and prognosis. The goal of this study was to quantify and localize skeletal muscle ACE-mRNA in patients with chronic heart failure and in control subjects, and to elucidate skeletal muscle fiber area and capillary density. METHODS AND RESULTS: Biopsies from the lateral vastus muscle were taken from 9 patients before and after treatment with enalapril and in 10 control subjects. ACE-mRNA was quantified with reverse transcription polymerase chain reaction. Immunohistochemistry was used to localize ACE within skeletal muscle. No difference in ACE-mRNA transcripts between patients and control subjects was detected, nor did ACE gene expression change after treatment with enalapril. The number of ACE-mRNA transcripts was related to muscle fiber area, whereas an inverse relationship between the number of ACE transcripts and capillary density was found. ACE was detected in the endothelial cells of capillaries in skeletal muscle. CONCLUSION: ACE is expressed in skeletal muscle and is confined to endothelial cells. The close relationship between capillary density and number of ACE transcripts indicate that activation of the renin-angiotensin system has an impact on capillary growth.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1998

Muscular performance in heart failure.

BACKGROUND: Some of the major symptoms in patients with chronic heart failure are muscle weakness and fatigue. However, not much is known about muscle performance in these patients compared to healthy controls. METHODS AND RESULTS: Activity level, gait speed, hand grip strength, muscle performance of the knee extensors and flexors along with the plantar and dorsal flexors of the foot were evaluated. Muscle biopsies from the lateral vastus lateralis were taken. Sixteen patients in New York Heart Association class II or III were tested and compared to 112 reference subjects. Compared to the reference subjects, there was a reduction in activity level, gait speed, isometric and isokinetic peak torque for knee extension at different velocities, hand grip strength, peak torque for plantar and dorsal flexion of the ankle and isometric and isokinetic endurance for the knee extension. Recovery was faster. There were small differences in fiber composition. 3-Hydroxy-acylCoA-dehydrogenase and citrate synthase were lower, and lactate dehydrogenase was increased. CONCLUSIONS: Muscle performance is affected in terms of both strength and endurance, which might affect performance in everyday activities. The more pronounced reduction in hand grip compared to the other muscles tested could be an indication of intrinsic abnormalities in the skeletal muscle.

Adult↗
PubMed1997

Skeletal muscle alterations in patients with chronic heart failure.

AIMS: To investigate skeletal muscle in patients with chronic heart failure and controls, and relate skeletal muscle variables to functional class, exercise capacity, central haemodynamics, muscle strength and medical treatment. METHODS: Biopsy from the lateral vastus muscle was obtained in 43 patients and 20 controls. Right sided heart catheterization was performed in 19 patients and maximal exercise testing in 26 patients. In nine patients muscle strength was measured. Patients had higher lactate levels, higher lactate dehydrogenase activity, and lower oxidative enzymes activity than controls. In patients, the percentage of type I fibres and capillarization were decreased while the percentage of type II B fibres were increased. Lactate dehydrogenase activity correlated with exercise capacity, muscle strength and right atrial pressure. Digoxin-treated patients had significantly lower oxidative enzyme activity than patients without digoxin treatment. CONCLUSION: Patients with chronic heart failure have several skeletal muscle abnormalities. Central haemodynamics and medical treatment may, in addition to inactivity, be important in skeletal muscle changes.

Adenosine Triphosphate↗
PubMed1996

Skeletal muscle changes in patients with chronic heart failure before and after treatment with enalapril.

To evaluate if enalapril treatment can influence skeletal muscle metabolism and histology we investigated 26 patients with congestive heart failure and 20 normal subjects. The patients were treated with enalapril for 3 months in addition to diuretics and digitalis. Biopsies from the lateral vastus muscle were taken before and after treatment. Citrate synthetase, 3-hydroxyacyl-CoA dehydrogenase and phosphorylase activities were significantly decreased in the patients compared with controls. The number of capillaries per fibre and the number of capillaries surrounding each fibre were significantly decreased among patients. After 3 months of enalapril treatment functional class improved significantly. The lactate dehydrogenase activity increased whereas the oxidative enzymes did not change significantly. The type I, II and II A fibre areas increased significantly after enalapril treatment. We conclude that patients with chronic heart failure have decreased activity of oxidative enzymes and of phosphorylase in skeletal muscle. They also have decreased capillarization in skeletal muscle. These changes were not influenced by enalapril treatment. The increase in muscle fibre area seen after enalapril treatment could be due to increased physical activity. The cause of increased muscle lactate dehydrogenase activity after enalapril treatment needs further investigation.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1996

Skeletal muscle metabolism during exercise in patients with chronic heart failure.

OBJECTIVE: To investigate the metabolic response of skeletal muscle to exercise in patients with chronic heart failure and determine its relation to central haemodynamic variables. SETTING: University hospital in Sweden. PARTICIPANTS: 16 patients in New York Heart Association class II-III and 10 healthy controls. MAIN OUTCOME MEASURES: Skeletal muscle biopsies were obtained from the quadriceps muscle at rest and at submaximal and maximal exercise. Right sided heart catheterisation was performed in eight patients. RESULTS: The patients had lower maximal oxygen consumption than the control group (13.2 (2.9) v 26.8 (4.4) ml/kg/min, P < 0.001). They had reduced activities of citrate synthetase (P < 0.05) and 3-hydroxyacyl-CoA dehydrogenase (P < 0.05) compared with the controls. At maximal exercise adenosine triphosphate (P < 0.05), creatine phosphate (P < 0.01), and glycogen (P < 0.01) were higher whereas glucose (P < 0.001) and lactate (P < 0.06) were lower in the patients than in the controls. Citrate synthetase correlated inversely with skeletal muscle lactate at submaximal exercise (r = -0.90, P < 0.003). No correlations between haemodynamic variables and skeletal muscle glycogen, glycolytic intermediates, and adenosine nucleotides during exercise were found. CONCLUSION: Neither skeletal muscle energy compounds nor lactate accumulation were limiting factors for exercise capacity in patients with chronic heart failure. The decreased activity of oxidative enzymes may have contributed to the earlier onset of anaerobic metabolism, but haemodynamic variables seemed to be of lesser importance for skeletal muscle metabolism during exercise.

Adenosine Triphosphate↗
PubMed1995

Skeletal muscle fiber composition and capillarization in patients with chronic heart failure: relation to exercise capacity and central hemodynamics.

Patients with chronic heart failure have structural and metabolic changes in skeletal muscle, which may be of importance for symptomatology. The origin of these changes are still unknown. The relationship between fiber composition and capillarization in skeletal muscle with exercise capacity and central hemodynamic variables was examined. Biopsies from the lateral vastus muscle were taken in 12 patients with chronic heart failure. Samples from eight normal subjects served as control samples. All patients underwent maximal exercise tests. Central hemodynamic variables were measured during exercise in five patients. The patients had a higher percentage of type II B fibers (P = .03) and fewer capillaries per fiber (P = .02) than the controls subjects. VO2 max correlated with the percentage of type I fibers, whereas the correlation with the type II A fibers was inverse. Cardiac index and pulmonary capillary wedge pressure at submaximal and maximal exercise were related to fiber type composition and relative fiber areas. Skeletal muscle fiber type composition and capillarization was changed in patients with chronic heart failure. These changes might influence exercise capacity. There were relationships between central hemodynamic variables and skeletal muscle changes. What the cause and effects were need further investigation.

Aged↗