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Biomedical subjects

S Bevegård

Publications and source records attributed to S Bevegård.

At least 19 recordsLinked to original sources
PubMed1999

Respiratory response to exercise in postpolio patients with severe inspiratory muscle dysfunction.

OBJECTIVES: To evaluate the limiting factors of exercise performance and to analyze the respiratory strategies adopted during exercise in postpolio patients with severe inspiratory muscle dysfunction. PATIENTS: Five patients with prior poliomyelitis associated with scoliosis and with respiratory muscle dysfunction (mean vital capacity, 1.74L [range, 1.1 to 2.4]) were studied at rest and during leg or arm cycle exercise. METHODS: Gas exchange was examined by arterial blood gases and mass spectrometry of expired air. Ventilatory mechanics were studied by measurement of esophageal and gastric pressures. RESULTS: Blood gases at rest were normal, except for subnormal PO2 levels in three patients. In all but one patient, ventilatory insufficiency was the limiting factor for exercise. A compensatory breathing pattern with abdominal muscle recruitment during expiration was present already at rest in three of the patients. The pressures generated by the diaphragm were below fatiguing margins, ie, levels that in healthy subjects can be sustained for at least 45 minutes. CONCLUSIONS: The extent of ventilatory dysfunction was not evident in blood gas values at rest; however, it was revealed by blood gas values during the exercise test. Diaphragm fatigue seems to be avoided at the cost of impaired blood gases.

Adult↗
PubMed1999

Myocardial sestamibi uptake in healthy subjects is related to age, gender and habitus.

The object of this study was to evaluate the effect of gender, age and anthropometric data on regional isotope uptake in myocardial perfusion scintigraphy using 99mTc-MIBI-SPECT (myocardial sestamibi single-photon emission technique). Seventy-one healthy, non-smoking subjects, 42 men and 29 women between 40 and 80 years of age, with less than 5% likelihood of having coronary artery disease were studied. All subjects underwent a maximal exercise and rest MIBI-SPECT using a 2-day protocol and a 180 degrees anterior circular rotation. No correction for scatter or attenuation was made. Normalized regional activity was different in men and women in the anterior and inferior regions, with higher values anteriorly in men and inferiorly in women. Regional activity also differed with age in both women and men with higher relative activity in the anterior regions in the oldest age groups. Higher activities were seen in the basal parts of the left ventricle at rest compared with stress in both men and women. Regional isotope uptake was significantly affected by habitus expressed as body mass index (BMI) and thoracic circumference. Different protocols for stress and rest seem to be needed for men and women in different age groups, and for stress and rest when performing semiquantitative MIBI-SPECT and comparing data with a normal file of healthy subjects. Furthermore, such anthropometric data as BMI and/or thoracic circumference should be considered in order to minimize the risk for false-positive or false-negative scintigraphic results.

Adult↗
PubMed1998

Pulmonary function following adjuvant chemotherapy and radiotherapy for breast cancer and the issue of three-dimensional treatment planning.

BACKGROUND AND PURPOSE: The frequency and grade of pulmonary complications following adjuvant radiotherapy for breast cancer are still debated. This study focuses on loss of pulmonary function. MATERIALS AND METHODS: We have measured the reduction of pulmonary function 5 months following radiotherapy in 144 node-positive stage II breast cancer patients by using pulmonary function tests. RESULTS: No deterioration of pulmonary function was detected among the patients who were treated with local radiotherapy. On the contrary, there was a mean increase in diffusion capacity by 7% (P = 0.004) following radiotherapy, which most likely was explained by the adjuvant chemotherapy administered prior to the baseline pulmonary function tests. Patients undergoing loco-regional radiotherapy showed a mean reduction in diffusion capacity by 5% (P < 0.001) and in vital capacity by 3% (P = 0.001). The subset of patients (9%) who were diagnosed with severe pulmonary complications needing cortisone treatment had significantly larger mean paired differences in vital capacity (-0.446 L, -15% (equivalent to 15 years of normal ageing or the loss of 3/4 of a lung lobe)) compared to the patients who were asymptomatic (-0.084 L) (P < 0.05). When the effects of potential confounding factors and different radiotherapy techniques were tested on the reduction of pulmonary function by stepwise multiple regression analysis, a significant correlation was found only to locoregional radiotherapy including the lower internal mammary lymph nodes. CONCLUSIONS: We conclude that a clinically important reduction of pulmonary function is seen in the subset of patients who are diagnosed with severe pulmonary complication following loco-regional radiotherapy for breast cancer. The results of this study warrant further studies based on individual lung dose volume histograms.

Adult↗
PubMed1995

ST-segment depression on ambulatory electrocardiography in the early in-hospital period after acute myocardial infarction predicts early and late mortality: a short-term and a 3-year follow-up study.

A surveillance study was conducted to determine the in-hospital and long-term prognostic value of ST-segment depression assessed by ambulatory electrocardiographic monitoring (AEM) during the early in-hospital period after acute myocardial infarction (AMI). ST-segment depression (STD) was determined by computer analysis of 24-h ECG tapes as a horizontal or downsloping change in ST level by > 0.1 mV from the reference base line. The ST level was measured 80 ms after the J point of all normally conducted complexes for > or = 1 min. All computer-detected ST events were verified by one trained reader. Tapes corresponding to 74 patients were analyzed. In addition, 23 tapes corresponding to age- and gender-matched controls were also analyzed. Patients were divided into two groups: 22 patients (30%) showed STD (Group A), and 52 patients (70%) had no episode of STD (Group B). Among controls, 1 person (4%) showed STD. During the early follow-up period (14 +/- 11 days after hospital admission), cardiac events occurred in 11 patients [7 (32%) in Group A and 4(8%) in Group B, p < 0.01], including 6 cardiac death [5 (23%) in Group A and 1 (2%) in Group B, p < 0.01], 3 acute coronary artery bypass surgeries [2 (9%) in Group A and 1 (2%) in Group B, p = NS], and 2 nonfatal myocardial infractions (both in Group A, p = NS). During a mean follow-up period of 3 years (36 +/- 15 months), 18 patients died [10 (45%) in Group A and 8 (15%) in Group B, p = 0.01]. Eleven deaths were sudden [7 (32%) in Group A and 4 (8%) in Group B, p < 0.01]. Eighteen AMI occurred [11 (50%) in Group A and 7 (13%) in Group B, p < 0.005]. Twenty patients underwent revascularization procedures [7 (32%) in Group A and 13 (25%) in Group B, p = NS].(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnosis, Computer-Assisted↗
PubMed1995

Sympathoadrenal responses to bronchoconstriction in asthma: an invasive and kinetic study of plasma catecholamines.

1. Bronchoconstriction does not seem to be a stimulus for sympathoadrenal activation, as judged by venous plasma concentrations of noradrenaline, adrenaline or neuropeptide Y-like immunoreactivity. However, venous measurements have methodological drawbacks. In the present study arterial and mixed venous (pulmonary arterial) levels of these variables were determined before and after histamine-induced bronchoconstriction in non-medicated asthmatic subjects. In addition, noradrenaline kinetics in plasma (isotope dilution) and the pulmonary overflows of noradrenaline and neuropeptide Y-like immunoreactivity were determined. 2. Histamine inhalation induced bronchoconstriction; forced expiratory volume in ls decreased by 38.7% +/- 4.1% (SE) and arterial PO2 by 3.0 +/- 0.9 kPa. This acute bronchoconstriction induced significant elevations of arterial and mixed venous plasma noradrenaline from < or = 1.18 nmol/l to > or = 1.40 nmol/l. The clearance of NA from plasma increased marginally. Thus, the arterial plasma NA response was due to increased spillover of noradrenaline to plasma (from 1.80 +/- 0.18 to 2.52 +/- 0.36 mmol min-1/m2 at maximal bronchoconstriction, with a subsequent further increase). There were no elevations of adrenaline or neuropeptide Y-like immunoreactivity in arterial plasma. 3. No sympathetic activation could be demonstrated in the lungs (pulmonary noradrenaline or neuropeptide Y-like immunoreactivity overflow), and no alterations in pulmonary vascular resistance or cardiac output were observed. Neither arterial nor mixed venous plasma concentrations of adrenaline were influenced by bronchoconstriction. 4. Acute bronchoconstriction thus leads to peripheral sympathetic activation (possibly due to the increased work of breathing) which does not involve the lungs.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Assessment of left ventricular wall motion in angina pectoris by two-dimensional echocardiography and myocardial perfusion by technetium-99m sestamibi tomography during adenosine-induced coronary vasodilation and comparison with coronary angiography.

Myocardial perfusion and regional wall motion during adenosine-induced coronary vasodilation were assessed in 40 patients with angina pectoris by technetium-99m sestamibi single-photon emission computed tomography (SPECT) and simultaneous 2-dimensional echocardiography. Adenosine was infused intravenously at a dose of 140 micrograms/kg body weight per minute for 6 minutes, and technetium-99m sestamibi was injected at 3 minutes. Adenosine caused a significant decrease in systolic and diastolic blood pressure and a significant increase in heart rate and the heart rate-blood pressure product. Adverse effects were mild and transient and no patient required aminophylline. Completely or partially reversible defects on SPECT were present in 28 patients, a fixed defect was seen in 4 patients, and no defect was seen in 8 patients. Two-dimensional echocardiography revealed a new or worsening wall motion abnormality in 21 patients, a fixed abnormality in 4 patients and no abnormality in 15. Transient perfusion defects were associated with transient wall motion abnormalities in 71% of cases. The overall sensitivity, specificity and predictive accuracy of adenosine echocardiography in detecting significant coronary artery disease (> 50% diameter stenosis) were 74, 100 and 78%, respectively, whereas those of adenosine SPECT were 94, 100 and 95%, respectively (p < 0.05, NS, and < 0.05, respectively). Thus adenosine technetium-99m sestamibi SPECT has a higher sensitivity and predictive accuracy than adenosine echocardiography, suggesting that adenosine-induced perfusion defects are not always associated with wall motion abnormality.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1993

Prognostic significance of exercise thallium-201 myocardial perfusion imaging compared to stress echocardiography and clinical variables in patients with unstable angina who respond to medical treatment.

The prognostic value of thallium-201 imaging in patients with unstable angina is not well established. Forty consecutive patients with unstable angina who had responded to medical therapy underwent predischarge symptom-limited exercise testing and 39 of them underwent exercise thallium-201 imaging, on average 3 days after the exercise test. Exercise echocardiography was performed in 36 of these patients in conjunction with the predischarge exercise test. Patients with previous myocardial infarction, coronary revascularization, left bundle branch block and dilated cardiomyopathy were not included in the study. An echocardiographic wall-motion score index was derived by analyzing left ventricular regional wall motion. During a follow-up period of 30 +/- 6.4 months, 3 patients had a non-fatal myocardial infarction and 20 required revascularization because of a recurrence of severe medically refractory angina. Univariate predictors of cardiac events (non-fatal myocardial infarction or a need for revascularization) during follow-up included ST-depression during exercise, positive exercise echocardiography, a low exercise wall-motion score index, the presence of thallium-201 redistribution and the number of myocardial segments with thallium-201 redistribution. However, stepwise logistic regression analysis revealed that the presence of thallium-201 redistribution was the only significant non-invasive predictor (P < 0.005) of a cardiac event among patients who underwent predischarge exercise testing and exercise thallium-201 imaging. Among patients undergoing exercise echocardiography and exercise thallium-201 imaging, the number of segments with thallium-201 redistribution was the only significant predictor (P < 0.0005) of future cardiac events.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Noninvasive test of microvascular endothelial function in normal and hypertensive pregnancies.

OBJECTIVE: To examine microvascular endothelial cell function in vivo in pre-eclampsia. DESIGN: Iontophoresis of acetylcholine (Ach), which gives rise to endothelial cell dependent vasodilatation, and of sodium nitroprusside (SNP), which elicits vasodilatation independently of functioning vascular endothelium. SETTING: Södersjukhuset, Stockholm, Sweden. SUBJECTS: Ten pre-eclamptic patients, ten healthy pregnant women and ten healthy nonpregnant women were examined. MAIN OUTCOME MEASURES: The degree of vasodilatation following iontophoretic administration of Ach compared with SNP was recorded with a laser Doppler technique, the data being analysed on a personal computer. RESULTS: Both Ach and SNP administration resulted in marked vasodilatation; the magnitude of the vasodilatation was similar in the three groups of women. CONCLUSION: Following iontophoretic administration of endothelial cell dependent or independent vasodilatators, laser Doppler measurement of blood flow demonstrated no microvascular endothelial cell dysfunction in pre-eclamptic women.

Acetylcholine↗
PubMed1992

Exercise echocardiography after stabilization of unstable angina: correlation with exercise thallium-201 single photon emission computed tomography.

The diagnostic usefulness of predischarge exercise echocardiography in 35 patients with unstable angina who responded to medical therapy was correlated with exercise thallium-201 single photon emission computed tomography (TI-SPECT) performed, on the average, three days after the exercise echocardiography. None of the patients had myocardial infarction prior to hospitalization or before TI-SPECT and none had left bundle-branch block on their rest electrocardiogram (ECG). Exercise echocardiography was positive in 21 patients and TI-SPECT in 24. The results of the two techniques were concordant in 28 of 35 patients (agreement = 80%, k = 0.57 +/- 0.14, p less than 0.001). Wall-by-wall comparison of the distribution of exercise-induced wall motion abnormalities with reversible thallium defects showed complete or partial correlation in all of 19 patients in whom both the tests were positive. A positive exercise ECG and positive exercise echocardiography identified 11 of 11 patients with angiographically verified significant coronary artery disease (CAD) and 11 of 12 patients (92%) with positive TI-SPECT. Thus, exercise echocardiography is a valuable addition to routine predischarge exercise test in the noninvasive diagnosis of myocardial ischemia and shows a good correlation with TI-SPECT in detecting and localizing ischemia in patients with unstable angina stabilized on medical therapy.

Angina, Unstable↗
PubMed1992

Early exercise thallium-201 single photon emission computed tomography in unstable angina: a prospective study.

To evaluate the safety and diagnostic value of early symptom-limited exercise electrocardiography (ECG) and exercise thallium-201 single photon emission computed tomography (SPECT) in unstable angina (UA), 39 patients were studied prospectively soon after stabilization on medical treatment. No patient had a history of myocardial infarction (MI) or revascularization and patients with left bundle branch block were excluded. Exercise ECG and exercise thallium-201 SPECT were performed 8 +/- 4 days and 11 +/- 6 days respectively after admission to hospital. Seventeen out of 39 patients (44%) had positive exercise ECGs and 22 (56%) negative or inconclusive ones. Exercise thallium-201 SPECT was positive in 26 patients (67%) and negative in 13 patients (33%). Thirty-one patients underwent coronary arteriography and 24 of them proved to have significant coronary artery disease (CAD). The sensitivity, specificity and positive predictive value of exercise ECG in detecting CAD are 62%, 86%, and 94% respectively while the corresponding results are 96%, 100%, and 100% for exercise thallium-201 SPECT. Therefore, it is concluded that the early symptom-limited exercise test is safe in medically stabilized patients with UA. Early exercise thallium-201 SPECT is highly sensitive and predictive of the presence of significant CAD among patients in the early recovery phase of UA and can be used in selecting this group of patients for coronary angiography and other therapeutic strategies.

Adult↗
PubMed1991

Plasma levels of atrial natriuretic peptide at rest and during exercise in heart failure--influence of cardiac rhythm and haemodynamics.

The relationship between plasma levels of immunoreactive atrial natriuretic peptide (ir-ANP), arginine vasopressin (AVP), cardiac rhythm and different haemodynamic variables were studied at rest and during exercise in 16 patients with heart failure undergoing heart catheterization for clinically indicated reasons. Even though there was no significant relationship between pulmonary capillary wedge pressure (PCW) and ir-ANP at rest (r = 0.39; P = 0.14) changes in these variables with exercise correlated well (r = 0.71; P = 0.002). Change in right atrial mean pressure, heart rate, mean arterial blood pressure or cardiac index did not significantly influence change in plasma levels of ir-ANP. The correlation between PCW and AVP at rest (r = 0.92; P less than 0.001) disappeared during exercise. Calculated ir-ANP/PCW ratios decreased slightly during exercise, but were not influenced by initial atrial pressures or atrial fibrillation. These observations provide evidence for a similar responsiveness of ANP in patients with sinus rhythm and atrial fibrillation. The ability of rapid change in ANP plasma levels during exercise was preserved and proportional to changes in PCW over a wide pressure range in the studied patient group. This finding indicates that left atrium distension rather than right atrium distension is the major determinant for the release of ANP in patients with congestive heart failure. The observed rapid responsiveness of ANP to change in left atrial pressure may allow the hormone to modulate haemodynamic response during short periods of exercise.

Adult↗
PubMed1991

Iontophoresis of vasoactive drugs. Effect on peripheral blood flow during pregnancy.

The aim of this study was to evaluate whether iontophoretic administration of the vasoactive agents noradrenaline (NA) and angiotensin (AII) combined with measurement of skin blood flow with a laser Doppler technique could serve as a predictive method for pre-eclampsia. Nine healthy non-pregnant women, 9 healthy pregnant women and 9 pre-eclamptic patients were investigated. A significant reduction of skin blood flow was induced by NA in all three groups and by AII in the non-pregnant group. There was no significant difference between healthy pregnant and pre-eclamptic patients in the degree of reduction of blood flow with respect to NA and AII administration.

Angiotensin II↗
PubMed1989

Asthma from childhood to adulthood--a follow-up study of 20 subjects with special reference to work capacity and pulmonary gas exchange.

Twenty men with a mean age of 24.9 years, who had moderate to severe asthma during childhood, underwent a follow-up examination of their physical fitness, working capacity, maximal oxygen uptake, and pulmonary function during and after physical work. Comparison was made with similar data obtained at the age of 10.9 years. The young men had a normal physical working capacity with a normal oxygen uptake of 3.65 +/- 0.56 L/min. The respiratory parameters and the arterial blood gases during work demonstrated values as in healthy individuals, and no differences between groups with mild and severe asthma during childhood were observed. The alveolar-arterial oxygen difference was normalized, compared to that at 10.9 years. Only a few subjects still had exercise-induced asthma with a postexercise fall of greater than 20% in FEV1 compared to childhood. The mean FEV1 values for the whole group after exercise were lowered and had not returned to the baseline level even after 20 minutes. Oxygen pressure (tension), arterial, measured during 20 minutes after work, demonstrated continuously decreasing values. This might reflect a persisting disturbance in the pulmonary ventilation perfusion relationship caused by the underlying asthma disease.

Adolescent↗
PubMed1989

Adrenoceptors in Raynaud's disease.

Experiments were designed to study adrenoceptor function in subjects with Raynaud's disease. Sympathetic agonists and antagonists were administered into the finger skin by iontophoresis, and the resulting change in local skin blood flow was evaluated by laser Doppler technique. The effects of norepinephrine (NE, stimulating alpha 1- and alpha 2-adrenoceptors), phenylephrine (stimulating alpha 1-adrenoceptors) were studied in 12 women with Raynaud's disease and in 12 healthy controls. Controls and cases showed a similar consistent vasoconstriction to NE and B-HT 933. All control subjects showed a vasoconstriction to phenylephrine. In contrast, the Raynaud subjects demonstrated a weaker vasoconstriction or even a vasodilation, especially to low concentrations of the drug. After blockade of the alpha 1-adrenoceptors by doxazosin in the controls, phenylephrine mimicked the reaction in Raynaud subjects. beta-Adrenoceptor agonists (isoprenaline and terbutaline) had no effect on finger blood flow in the examined finger skin area in either control or Raynaud subjects. We suggest that Raynaud's disease is characterized by a defect in alpha 1-adrenoceptor function.

Adult↗
PubMed1988

Pseudoaneurysm--a treatable form of cardiac rupture.

Pseudoaneurysm is an unusual complication of myocardial infarction. Although its pathogenesis is known, the course of the condition is obscure. The diagnosis is usually made post-mortally. We present a case of a pseudoaneurysm following a myocardial infarction, diagnosed at a routine polyclinical echocardiographic examination in a patient who at the time of diagnosis was free of symptoms. The patient was successfully operated upon.

Aged↗
PubMed1988

Atrial natriuretic peptide during acute treatment of congestive heart failure.

Atrial natriuretic peptide (ANP) induces potent diuretic/natriuretic, vasorelaxing and aldosterone inhibitory effects. Increased plasma levels in congestive heart failure (CHF) have been reported. The aim of this study was to investigate plasma immunoreactive ANP (ir-ANP) levels during acute treatment of CHF. Seven patients with CHF underwent cardiac catheterization. Ir-ANP plasma levels were followed up to two h after administration of an orally given phosphodiesterase inhibitor (Milrinone); a substance with positive inotropic and peripheral vasodilating properties. In all patients cardiac output increased and cardiac filling pressures decreased markedly. Initially high ir-ANP plasma levels decreased. Our patients did not have an increased blood volume. It is concluded that plasma ir-ANP levels in the pulmonary artery rapidly decrease when atrial pressure is reduced. These data suggest that atrial pressure is the major determinant for release of ir-ANP in man and that the ability to respond quickly to changes in cardiac filling pressures is maintained in patients with severe CHF. Plasma ir-ANP levels may also become useful as an index of the degree of heart failure and serve as a tool in monitoring response to drug therapy.

Adult↗