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Biomedical subjects

T Bjurö

Publications and source records attributed to T Bjurö.

18 recordsLinked to original sources
PubMed1990

Excretion of thromboxane A2 and prostacyclin metabolites before and after exercise testing in patients with and without signs of ischemic heart disease.

We addressed the hypothesis that platelets are not activated in association with effort-induced myocardial ischemia in stable coronary disease. Seventy-two patients undergoing a diagnostic bicycle exercise test were stratified according to the development of chest pain (yes/no, 33/39) and of exercise-induced ST-segment depression of at least 200 microV in the electrocardiogram (yes/no, 12/60). Noninvasive indexes of platelet activation and of platelet/vessel wall interaction (urinary excretion of the 2,3-dinor-metabolites of thromboxane A2 [Tx-M] and prostacyclin [PGI-M], respectively) were analyzed in samples collected in the basal state and after the test. Basal Tx-M and PGI-M did not differ in patients with (236 +/- 35 and 131 +/- 22 pg/mg creatinine, respectively) and without (185 +/- 16 and 101 +/- 13 pg/mg creatinine, respectively) chest pain, or in those with (178 +/- 45 and 162 +/- 41 pg/mg, respectively) and without (216 +/- 22 and 104 +/- 11 pg/mg, respectively) ST-segment depression during the test. Patients without chest pain or without ST-segment depression moderately increased (p less than 0.05) their urinary Tx-M (by 21% and 13%, respectively) and PGI-M (by 28% and 23%, respectively) after exercise. No significant increases were observed in those developing chest pain or ST depression during exercise. These data indicate that effort-induced myocardial ischemia is not associated with an increase in platelet activation or platelet/vessel wall interaction in patients with stable coronary disease.

Coronary Disease↗
PubMed1989

A cross-sectional analysis of glucose tolerance and cardiovascular disease in 67-year-old men.

The relationship between degree of glucose tolerance and cardiovascular disease has been studied in a cross-sectional population survey of 644 men born in 1913, randomly sampled and examined at the age of 67. The cohort was divided into different groups according to current diagnostic criteria for diabetes and impaired glucose tolerance. An almost 2-fold higher prevalence of hypertension, myocardial infarction, angina pectoris, and congestive heart failure was found in the group with impaired glucose tolerance compared to the group with a normal glucose tolerance. Fifty per cent of the men with impaired glucose tolerance were being treated with some drug for cardiovascular disease, usually diuretics for hypertension. Intermittent claudication showed a 2.5-fold higher prevalence among the diabetic patients. A computerized 12-lead exercise-ECG test, with a unique accuracy in measuring ST-segment changes, was performed in a subset of 135 men. This showed no association between ST-segment depression and different degrees of glucose tolerance, even when accounting for confounding factors such as treatment with beta-blocker agents or digoxin, pathological Q-waves, and differences in maximal heart rate.

Aged↗
PubMed1988

Correlation of coronary arteriography after acute myocardial infarction with predischarge limited exercise test response.

This study of post-acute myocardial infarction (AMI) patients compared the extent and distribution of coronary narrowings and left ventricular dysfunction in 45 patients who had greater than or equal to 1 mm ST-segment depression on a predischarge low-level exercise test (positive-result group) with those found in 78 patients who had less than 1 mm ST depression (negative-result group). Cardiac catheterization was done 50 +/- 20 days (mean + standard deviation) after AMI. Patients with positive responses more often had multivessel coronary artery disease (80 vs 47%, p = 0.001) and a greater than or equal to 75% narrowing in the left anterior descending (LAD) (87 vs 62%, p = 0.003) and left circumflex (71 vs 37%, p = 0.001) arteries, as well as in the proximal LAD segment before the first septal branch (58 vs 29%, p = 0.002). Among patients with positive responses 93% had normal or hypokinetic wall motion in the vascular territory of a severely diseased coronary artery (viable but potentially ischemic myocardium) while 63% of the negative-result group had these findings (p = 0.001). No difference in ejection fraction could be identified between the 2 groups (54 +/- 15% vs 54 +/- 16%). Prior studies of AMI patients have shown that ST-segment depression on a predischarge low-level exercise test will identify patients at higher risk of subsequent cardiac death. Our observations have identified differences in cardiac angiographic findings between patients with positive and negative responses to this test that may explain this difference in outcome.

Coronary Angiography↗
PubMed1988

Effects of cold on ST amplitudes and blood pressure during exercise in angina pectoris.

To investigate the mechanisms of cold susceptibility in angina pectoris nine male angina patients were studied. All were cold susceptible by history and had developed ischaemic ST changes during a previous exercise test. The patients underwent two additional bicycle exercise tests, one in a cold chamber with an average temperature of -8 degrees C, and the other at room temperature. The ECG was computer analysed and the intra-arterial blood pressure was measured. No significant decrease in work capacity was found during exercise in the cold chamber. In the cold, systolic blood pressure was consistently higher throughout the test and in seven of nine subjects ST depression was more pronounced at corresponding workloads. ST depression was also analysed versus heart work which was assessed as rate pressure product. In the cold, 1 mm ST depression appeared at a somewhat higher rate pressure product when compared to room temperature. It was concluded, therefore, that an augmented heart work, secondary to substantial increases in blood pressure, appears to account for the cold-induced increase in ST depression found in the angina patients in this study.

Adult↗
PubMed1988

Early heart failure in the population. The study of men born in 1913.

A cross-sectional analysis of characteristics possibly associated with congestive heart failure (CHF) was performed among 644 men, all 67 years of age and randomly selected from the general population. A total of 13% had symptoms and signs of overt CHF. Another 10% had early or "latent" CHF. Among overt CHF cases, 46% had hypertension, 55% coronary heart disease and 79% any one of these conditions. Among "latent" CHF cases, the corresponding proportions were 52%, 25% and 65%. Simple indices of left ventricular diastolic function and filling pressure as well as of pulmonary artery pressure were closer related to the CHF stage, than were measures of systolic left ventricular function. Smoking habits, hypertension, blood lipids, weight and other measures of body fat, blood glucose, and serum insulin were all correlated to CHF stage. In a multivariate analysis, smoking habits, hypertension, body weight, and serum insulin were independently and significantly correlated to CHF stage.

Aged↗
PubMed1987

Cardiac anti-ischemic effect of metoprolol: role of beta-blockade within the ischemic region.

The distribution of metoprolol and atenolol into ischemic and nonischemic myocardium was studied in anesthetized dogs, pigs, and cats. The beta-blockers were administered intravenously after coronary artery occlusion. Metoprolol was found to be significantly more efficiently distributed to the ischemic myocardium than atenolol in all three species. To investigate the functional implications of this difference in tissue distribution, the anti-ischemic effects of the two beta-blockers were studied in the 2-h period following coronary artery occlusion in anesthetized cats, in which heart rate was kept at a constant level. In this model, metoprolol (0.3 mg.kg-1 + 0.15 mg.kg-1.h-1) was found to attenuate or delay the developing ischemic process. This is shown by its significant reduction of (a) the decline of CK activity in ischemic myocardium, (b) the ST elevation in a precordial ECG lead, and (c) the decrease of arterial pressure and cardiac output. In contrast to metoprolol, atenolol (0.3 mg.kg-1 + 0.15 mg.kg-1.h-1) caused no significant anti-ischemic effect in this cat model. The difference in the effectiveness of the two drugs can most probably be explained by their differential distribution in the ischemic heart. Furthermore, the anti-ischemic effect of metoprolol shows that the presence of a beta-blocker in ischemic left ventricular myocardium can favorably affect the early phase of developing infarction.

Adrenergic beta-Antagonists↗
PubMed1977

Physical training in man. Skeletal muscle metabolism in relation to muscle morphology and running ability.

The metabolic and morphologic adaptation to physical training in skeletal muscle tissue of eleven middle-aged, physically untrained men was studied. Muscle biopsies were taken from the vastus lateralis before, after 8 weeks and after 6 months of physical training for analysis of metabolic and morphologic variables. Glucose tolerance test indicated increased insulin sensitivity after 6 months of physical training. The activities of glycogen phosphorylase, hexokinase and glucose-6-P-dehydrogenase were increased but other enzymes involved in glycogen turnover and glycolysis were unchanged after 6 months of physical traning. The activities of citrate synthase and cytochrome-c-oxidase, representing the oxidative capacity were significantly increased already after 8 weeks of physical training. The incorporation rate of palmitate-carbon into CO2 and triglycerides increased, and the incorporation rate of leucine-carbon into CO2 decreased with 6 months of physical training. The fiber diameter of both Type 1- and Type 2-fibers increased, while the mitochondrial volume increased predominantly in Type 2-fibers. Significant correlations were found between metabolic, physiologic and morphologic variables before and after physical training. The results indicate an increased oxidative capacity, mainly located to Type 2-fibers, and an increased utilization of fatty acids in response to this type of physical training.

Carnitine↗
PubMed1975

Ergonomic studies of standardized domestic work in patients with neuromuscular handicap.

A model for ergonomic studies of domestic work in varying patient groups has been constructed. A control group of 15 healthy women, 30-59 years of age, 9 female patients with hemiplegia and 13 with multiple sclerosis (MS) were studied with exercise test on a bicycle ergometer. Recordings of time consumption, heart rate and subjectively perceived exertion were made during a 4.5-5 hour domestic work program. Four of the more strenuous work elements were restudied also with respect to oxygen uptake. The hemiplegic patients required more time and had higher perceived exertion, but lower heart rate and oxygen uptake for the same work tasks than did the controls. The MS-patients also had higher perceived exertion. There was a rather poor relationship between determined and indirectly estimated energy expenditure. Various explanations are discussed. The results demonstrate the importance of the perceived exertion in choosing the work intensity.

Activities of Daily Living↗
PubMedDate not supplied

The importance of nose-breathing for the systolic blood pressure rise during exercise.

The effect of nose breathing on the systolic blood pressure was examined in ten healthy men. Nose breathing was increased above normal by exercise and tested by maximum bicycle ergometry. When the anterior part of the nose was dilated with Nozovent the nasal airflow increased by on average 29%. In this condition, all ten men could cycle at maximum load without mouth breathing and there was a significantly lower increase (13 mmHg) in the systolic blood pressure than when the nasal dilator was not used. The reason for this lower blood pressure increase is unknown. The hypothesis is put forward, however, that facilitated nose breathing decreases the respiratory work, which in turn lowers the systolic blood pressure during exercise.

Adult↗