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Biomedical subjects

J Engvall

Publications and source records attributed to J Engvall.

35 records · Page 2Linked to original sources
PubMed1994

Exercise echocardiography and thallium 201 single-photon emission computed tomography in male patients after an episode of unstable coronary artery disease.

To compare modern, digital exercise echocardiography and thallium 201 single-photon emission computed tomography (SPECT) in patients with unstable coronary artery disease, 65 men unselected with regard to echocardiography were prospectively investigated 1 month after an episode of unstable angina or non-Q-wave myocardial infarction. Exercise echocardiography and 201Tl SPECT were performed on consecutive days in connection with a standard symptom-limited upright bicycle test and analyzed in a 9-segment model. Coronary angiography was performed in all but 1 patient and 60 patients had significant coronary lesions. Wall motion abnormalities were seen in 53 patients (81%) at rest and perfusion defects in 57 patients (88%) at the redistribution images. New or worsening of wall motion abnormalities were seen in 55 patients, either seated at peak exercise or recumbent after exercise, and 43 patients had reversible or partially reversible 201Tl scintigraphic defects (P = .02). The segmental agreement between wall motion abnormalities and scintigraphic defects was low (58%). The additional value of exercise echocardiography and 201Tl SPECT to exercise test was greatest in patients with one-vessel disease. Thus, 1 month after an episode of unstable coronary artery disease in men, there is a high incidence of significant coronary stenoses as well as signs of ischemia shown both by wall motion abnormalities during exercise echocardiography and by postexercise studies with 201Tl SPECT. Exercise echocardiography gives a higher diagnostic yield regarding occurrence of reversible ischemia.

Adult↗
PubMed1992

Exercise echocardiography: a methodological study comparing peak-exercise and post-exercise image information.

It is unclear whether echocardiography at peak bicycle exercise adds information to registrations obtained recumbent immediately after the test and what factors influence image quality. Therefore, exercise echocardiography was performed consecutively and prospectively in 66 men, unselected with regard to echocardiography, one month after an episode of unstable coronary artery disease. Of 594 segments (9 x 66), 569 (96%) were adequately visualized recumbent at rest. The corresponding figures recumbent directly after exercise, seated before exercise, and seated at peak exercise were 544 (92%), 474 (80%), and 428 (72%), respectively. In the majority of our patients, acceptable images at peak exercise were obtained for the septal region, while for the anterior, lateral, and inferior segments the success rate varied from 50 to 70%. Recumbent after exercise, the success rate was acceptable for most segments, possibly with the exception of the apical and lateral segments. Fifty-five patients developed new wall motion abnormalities or worsening of wall motion in connection with exercise. Echocardiography at peak exercise provided more information than afterwards in patients with images of good quality. However, in patients with inferior image quality, the registrations obtained recumbent after the test revealed wall motion abnormalities which were not obtained seated at peak exercise. Patients with worse image quality had significantly higher respiratory rate and weight, and rated a higher degree of dyspnoea at peak exercise than those with good quality. We conclude that in middle aged men with coronary artery disease, image acquisition at peak bicycle exercise and immediately after exercise are of complementary value.

Adult↗
PubMed1991

Coarctation of the aorta--a theoretical and experimental analysis of the effects of a centrally located arterial stenosis.

Aortic coarctation is a local constriction of the aorta that may severely affect haemodynamics. It is therefore important to quantify these effects. Using Bernoulli's equation and the momentum theorem, the pressure drop is described including the pressure recovery distal to the coarctation and the effects of collateral flow; both laminar and turbulent. Assuming the coarctation and collaterals to be stiff, a quadratic relationship between flow and pressure drop is expected for flow through the coarctation and for turbulent collateral flow. For laminar collateral flow, a linear relationship is expected. The coarctation flow was studied in a model consisting of a rigid tube with local constriction, connected to a flooded-level tank, containing a 36 per cent by weight solution of sucrose, with a viscosity equivalent to that of blood at body temperature. The pressure drop across the constriction showed a quadratic relationship to flow in agreement with theoretical expectations. Pressure recovery in this model was very slight (0-4 mm Hg). Nine patients with aortic coarctation were catheterised. Cardiac output and pressure drop across the coarctation were measured at rest and during supine cycle exercise at two different workloads. The relationship between mean pressure drop and cardiac output tended to be either 'parabolic' or, in some cases, approximately linear, suggesting that the flow situation in aortic coarctation can be quantified by expressions that either linearly or quadratically relate pressure and flow.

Adult↗
PubMed1990

Effects of cardiac rehabilitation after coronary artery bypass grafting on readmissions, return to work, and physical fitness. A case-control study.

In a case-control study 49 consecutive post-coronary artery bypass grafting (CABG) patients (10 f, 39 m) participating in a comprehensive rehabilitation programme were compared with 98 individually matched double control patients, receiving standard care. The rehabilitation programme, starting 6 weeks after surgery, consisted of follow-up at a coronary clinic, repeated health education, and physical training in out-patient groups. During the first year after CABG, fewer study group patients were readmitted to hospital (14% vs 32%, p less than 0.01) and on fewer occasions (1.1 vs 2.9, p less than 0.05). Fewer patients used anxiolytic drugs (0% vs 15%, p less than 0.01). At the one year post-CABG exercise test we found in the study group a tendency to a greater increase in work capacity, as compared with the values obtained at the preoperative exercise test (33 vs 25 W ns). There were no differences in the rates of returning to work (59% vs 64%). In a long-term follow-up study (av. 38 months post-CABG) the patients were asked to fill in a questionnaire evaluating perceived physical work capacity and training habits. The study group patients rated their physical work capacity higher, and more patients had continued with regular physical training (66% vs 46%, p = 0.05). There were fewer patients using anxiolytic drugs (9% vs 30%, p less than 0.01). Although the programme did not influence the return to work we conclude that it improved the quality of life of our patients as it entailed fewer readmissions and reduced the use of anxiolytic medication; in addition it promoted physical fitness and training habits.

Adult↗
PubMed1990

Cardiac rehabilitation after coronary artery bypass grafting: effects on exercise performance and risk factors.

After coronary artery bypass grafting (CABG), 49 nonselected patients followed a cardiac rehabilitation program that included medical follow-up and physical training, both in outpatient groups and on an individual basis at home. The effect of the program on exercise test variables, coronary risk factors, and medication one year after surgery was compared to a nonexercised control group (n = 98). The study group showed less increase in the rate-pressure product, indicating a favorable effect on myocardial oxygen consumption (0.7 +/- 5.4 vs 2.8 +/- 5.6, p less than .05); a lower frequency of angina at exercise testing (6% vs 18%, p less than .01); a reduction in resting systolic and diastolic blood pressure (9/4mmHg, p less than .01); fewer smokers (6% vs 17%, p less than .05); and fewer patients taking long-acting nitrates (0% vs 10.2%, p less than .05). It is suggested, therefore, that an organized cardiac rehabilitation program may be advantageous after CABG.

Blood Pressure↗
PubMed1989

Arm and ankle blood pressure response to treadmill exercise in normal people.

Nineteen healthy volunteers, 10 men and nine women (mean age 38 and 30 years), exercised on a treadmill. The systolic blood pressure (BP) was measured at the ankle and in the arm after submaximal (8 min with a final load of 2 W kg-1 body weight) and maximal exercise. The BP was measured for 10 min after exercise, or until the elimination of a negative pressure difference between ankle and arm. The pre-study resting systolic arm and ankle pressures were 122 +/- 11 and 144 +/- 13 mmHg. One minute after submaximal exercise, arm and ankle BP were 147 +/- 18 and 159 +/- 19 mmHg (ankle-arm pressure difference 12 +/- 13 mmHg); 1 min after maximal exercise the corresponding figures were 182 +/- 26 and 153 +/- 35 mmHg (ankle-arm pressure difference -29 +/- 33 mmHg). We conclude that maximal exercise, but not an appropriately chosen submaximal exercise level, causes a negative BP difference between ankle and arm in normal people.

Adolescent↗
PubMed1988

Abrupt withdrawal of isosorbide-5-mononitrate in Durules (Imdur) after long term treatment in patients with stable angina pectoris.

In a single-blind study of 6 weeks' duration, 32 patients with stable angina pectoris, who had been receiving controlled-release, Durules, isosorbide-5-mononitrate (Imdur) 60 to 180 mg daily for at least 1 year, were assessed after abrupt withdrawal of the nitrate. After 2 weeks of placebo treatment nitrate therapy was re-instituted, and the patients followed for another 2 weeks. The possibility of development of tolerance and rebound phenomena was also investigated. Three patients experienced severe anginal symptoms necessitating hospitalization when controlled-release isosorbide-5-mononitrate was withdrawn abruptly. Patients complained of more severe anginal symptoms during the placebo period, experienced more frequent anginal attacks and used more glyceryl trinitrate tablets than during active treatment. ST segment changes during exercise were more pronounced with placebo. After controlled-release isosorbide-5-mononitrate was re-introduced, these variables indicated significant improvement. On the other hand, no deterioration occurred in exercise performance during the placebo phase. Responsiveness to glyceryl trinitrate was maintained, as shown by comparisons of exercise tests performed after the long term treatment and during the placebo phase. Controlled-release isosorbide-5-mononitrate retains a beneficial effect in patients with angina pectoris during prolonged use, although some attenuation of the effect is seen. Abrupt withdrawal of the drug is not recommended because of the possibility of severe exacerbation of anginal symptoms, although no clearcut rebound phenomena were seen.

Acute Disease↗
PubMed1988

Anti-anginal efficacy of a controlled-release formulation of isosorbide-5-mononitrate once daily in angina patients on chronic beta-blockade.

The anti-anginal effect of a controlled-release (Durules) formulation of isosorbide-5-mononitrate (5-ISMN) 60 mg, Imdur, once daily was evaluated in a randomised double-blind, placebo-controlled, crossover study with a placebo run-in period. Each period lasted for 2 weeks. A total of 70 patients (58 men and 12 women) with stable exertional angina pectoris on beta-blockade, mean age 59 years (range 39-71), were included. Exercise testing was performed on a bicycle ergometer 3 hours after the dose at the end of each period. Anginal attacks and intake of sublingual nitroglycerin tablets were noted. Imdur in combination with a beta-blocker significantly increased the total exercise capacity, the time and total work until the onset of chest pain and at 1 mm ST-depression compared with beta-blockade alone. The attack rate and the nitroglycerin consumption were significantly decreased. Headache was the only significant side-effect. In conclusion, the addition of Imdur once daily to beta-blockade significantly increased the anti-anginal effect.

Adrenergic beta-Antagonists↗
PubMed1987

Abrupt withdrawal of isosorbide 5-mononitrate (Imdur) after long term treatment in stable angina pectoris. A preliminary report.

32 patients with stable angina pectoris who had been receiving a controlled-release formulation Durules of isosorbide 5-mononitrate (Imdur) 60 to 120 mg daily with concomitant beta-blocker therapy for at least 1 year were entered into a study to evaluate possible rebound phenomena from the abrupt withdrawal of isosorbide 5-mononitrate and to determine whether nitrate tolerance had developed. Isosorbide 5-mononitrate was abruptly withdrawn and substituted with placebo for 2 weeks, after which the active drug was reintroduced. No deterioration of exercise performance could be detected during withdrawal of therapy, but an increase was seen after reinstitution. No tolerance was found for systolic blood pressure and ST segment changes or for the number of anginal attacks and short-acting glyceryl trinitrate tablets consumed. Three patients had to be hospitalised because of a sudden deterioration of symptoms on withdrawal of isosorbide 5-mononitrate. It was concluded that isosorbide 5-mononitrate in Durules has a beneficial effect and that tolerance does not appear to be clinically relevant.

Adrenergic beta-Antagonists↗
PubMed1983

Cellular enzymatic differentiation in brain vessels of normal and protein-deprived rats. Biochemical studies.

Brain capillary development was studied in normal and protein-deprived rats using the specific activity of alkaline phosphatase (EC 3.1.3.1) and gamma-glutamyl transpeptidase (EC 2.3.2.1) in whole brain homogenates and microvessels obtained by gradient centrifugation according to Orlowski et al. (1974). Pre- and postnatal protein deprivation was induced by a 50% reduction in the dietary protein content. The density of microvessel fragments changed during development. Most of the early developmental increase in the specific activity of both enzymes in whole brain homogenates of normal rats can probably be explained by a rapid formation of new capillary segments. The increase in specific activity of gamma-glutamyl transpeptidase in microvessels was interpreted as a sign of cellular differentiation. Protein deprivation resulted in reduced specific activity of both enzymes in whole brain homogenates of 30-day-old rats, probably as a result of the decreased length per volume of the cerebral capillary network at this age (Conradi et al. 1979a). Signs of impaired endothelial growth were also present in the protein-deprived rats since the distribution of microvessel fragments in the 30-day-old protein-deprived rats was similar to that in 3-week-old normal rats. The specific activity of alkaline phosphatase was decreased in the microvessel fractions of 30- and 96-day-old protein-deprived rats, apparently signifying an effect of the protein deprivation on the endothelial cells. These effects of protein deprivation on the brain capillary endothelial transport system may have negative consequences for growth and function in the brain.

Age Factors↗
PubMed1979

Effects of local extraneural application of diphtheria toxin on the sciatic nerves of normal and protein deprived rats.

Diphtheria toxin was locally administered around the sciatic nerves of normal and protein deprived rats aged 3, 6, 12, and 26 weeks in order to investigate the permeability of the barriers enveloping the nerves. At all ages the rats developed a reversible hind limb paralysis linked to a severe segmental demyelination, indicating passage of the toxin into the endoneurium. From 6 weeks of age the pattern of reaction differed between the protein deprived and control rats. The differences are interpreted as being partly dependent on less efficient protective barriers of the sciatic nerves of the protein deprived rats.

Animals↗
PubMedDate not supplied

Prevalence of hypertension among cadmium-exposed workers.

In a retrospective study of 311 male workers in an alkaline battery factory, the relationship between exposure to cadmium oxide and hypertension has been investigated. Blood pressure measurements, taken by the same physician, were available for a 30-yr period. When age-matched groups of hypertensive and normotensive workers were compared, employment time was significantly longer (P = .0109) in the hypertensive group. This indicates a possible relationship between exposure to cadmium oxide and the development of hypertension.

Adult↗