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Biomedical subjects

E Bielen

Publications and source records attributed to E Bielen.

14 recordsLinked to original sources
PubMed2000

Multicenter double-blind, randomized, placebo-controlled trial of levetiracetam as add-on therapy in patients with refractory partial seizures. European Levetiracetam Study Group.

PURPOSE: To evaluate the efficacy and tolerability of levetiracetam (LEV, Keppra) as add-on therapy in patients with refractory partial seizures. METHODS: In this European multicenter, double-blind, randomized, placebo-controlled trial, LEV (500 or 1,000 mg twice daily) was compared with placebo as add-on therapy in 324 patients with uncontrolled simple or complex partial seizures, or both, with or without secondary generalization. After enrollment, three parallel groups were assessed during a baseline period of 8 or 12 weeks, followed by a 4-week titration interval and a 12-week evaluation period. RESULTS: LEV significantly decreased partial seizure frequency compared with placebo. A reduction in seizure frequency of > or =50% occurred in 22.8% of patients in the 1,000-mg group and 31.6% of patients in the 2,000-mg group, compared with 10.4% of patients in the placebo group. Administration of LEV did not affect plasma concentrations of concomitant antiepileptic drugs or alter vital signs or laboratory parameters. No significant difference in the incidence of adverse events was observed between treatment groups (70.8% for the 1,000-mg group and 75.5% for the 2,000-mg group), or between the LEV and placebo groups (73.2% for placebo group). The most commonly reported adverse effects in the LEV group were asthenia, headache, and somnolence. CONCLUSIONS: The antiepileptic efficacy and tolerability of LEV (1,000 mg/d and 2,000 mg/d, administered in two divided doses) as add-on therapy was established in patients with refractory partial seizures in this clinical study.

Anticonvulsants↗
PubMed1993

Response of ambulatory blood pressure to antihypertensive therapy guided by clinic pressure.

The objective of this prospective study was to define the limits below which ambulatory blood pressure (BP) does not decrease in patients with essential hypertension, when the decision to institute and intensify drug treatment is based on conventional blood pressure measurements. After a 1 month placebo run-in period, 30 patients were treated for 1 year with the converting enzyme inhibitor lisinopril or the calcium antagonist isradipine; dose adjustments and the decision to add hydrochlorothiazide were based on conventional blood pressure measurements in the clinic. Ambulatory blood pressure was recorded during 24 h in the run-in period and after 16, 24, and 52 weeks of active therapy. The baseline ambulatory blood pressure below which pressure does, on average, not decrease during active treatment was defined as the pressure at which the regression line between the on-treatment pressure and blood pressure in the run-in period intersects the line of identity. The systolic/diastolic blood pressure limits were similar for the three assessments during active treatment and averaged 128/88 mm Hg for daytime, 106/73 mm Hg for nighttime pressure, and 119/81 mm Hg for the whole 24 h, with upper 95% confidence limits of 137/93, 115/78, and 127/86 mm Hg, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Cardiac variables and blood pressure as determinants of left ventricular inflow velocities.

The determinants of the left ventricular diastolic transmitral flow pattern, measured by use of Doppler velocimetry, were assessed in 40 patients referred for hypertension. The ratio of the atrial to early filling peak velocity (A/E ratio) averaged 0.82 +/- 0.23, BP 156 +/- 19/100 +/- 13 mmHg and left ventricular mass 220 +/- 57. In multiple regression analysis the A/E ratio was independently and positively related to age (P < 0.001) and BP (P < 0.001) and inversely to the fractional shortening of the left ventricular internal diameter (P < 0.01) and left atrial size at end-systole (P < 0.05); these variables accounted for 71% of the variance of the A/E ratio. The peak flow velocity during atrial contraction was positively and independently related to age (P < 0.001), BP (P < 0.05) and heart rate (P < 0.05); early filling velocity decreased with age (P < 0.001) and was positively related to heart rate (P < 0.01), left atrial diameter (P < 0.01) and fractional shortening (P < 0.001). The weak positive associations of the A/E ratio with left ventricular mass (r = 0.32; P < 0.05) and wall thickness (r = 0.38; P < 0.05) did not persist in multiple regression analysis. In conclusion, the left ventricular diastolic filling indexes are related to age, BP, left atrial size and to systolic left ventricular function but left ventricular structural variables, as measured by echocardiography, are not significantly involved.

Adult↗
PubMed1992

Automated versus observer blood pressure as determinants of left ventricular structure.

We studied the contribution of automated blood pressure measurements to the variation in left ventricular structural characteristics, independent of pressure measured by an observer. Thirty eight patients referred for hypertension underwent 24 h blood pressure monitoring. Echocardiography and repeated blood pressure measurements were taken on 2 different days by an observer and by the use of the Dinamap 845 device. Blood pressure by the observer averaged 157/101 mmHg, Dinamap pressure 152/94 mmHg, 24 h pressure 137/92 mmHg, left ventricular mass 218 g and mean wall thickness 12.7 mm. Left ventricular mass and wall thickness were related (P < 0.05) to systolic observer (r = +0.46; r = +0.47), Dinamap (r = +0.42; r = +0.41) and 24 h blood pressure (r = +0.46; r = +0.53); the correlation coefficients were lower (r = +0.35 to +0.51; P < 0.05) for diastolic pressure. These relations were independent of age, gender, height, weight and heart rate. The Dinamap pressure did not contribute to the difference in the left ventricular structural characteristics, independent of the observer pressure. The 24 h ambulatory pressure explained a small but significant (P < 0.05) fraction of the variation in mean wall thickness in addition to the observer pressure. Left ventricular mass and mean wall thickness were not related to the day-night difference in blood pressure (P > 0.25). In conclusion, observer, Dinamap and ambulatory pressures are significantly related to cardiac structural variables. Ambulatory pressure, but not Dinamap pressure, explains a small part of wall thickness variance in addition to well-standardized pressure measured by an observer.

Adult↗
PubMed1991

The inheritance of left ventricular structure and function assessed by imaging and Doppler echocardiography.

The heritability of left ventricular structure and function was studied in 53 pairs of monozygotic and dizygotic twins, aged 18 to 31 years, by means of M-mode and Doppler echocardiography. A significant fraction of the phenotypic variances of left ventricular wall thickness was explained by genetic variance. For the left ventricular internal dimension, however, no genetic effect was found after correction for body weight. After appropriate adjustment a genetic component of 32% was found for aortic peak flow velocity, 55% for stroke distance, and 47% for minute distance. The early and late diastolic peak flow velocities at the mitral valve showed a genetic component estimated at 43% and 26%, respectively. The inheritance of the late/early diastolic peak flow velocity ratio was estimated at 53%. In conclusion, these data suggest a significant genetic component for left ventricular structural features but not for cavity dimension. A significant influence of heredity was detected for left ventricular inflow and outflow characteristics.

Adult↗
PubMed1991

Heritability of aerobic power and anaerobic energy generation during exercise.

Twenty-nine pairs of monozygotic twins and 19 pairs of dizygotic twins, all male, ages 18-31 yr, performed a graded uninterrupted exercise test on the bicycle ergometer to exhaustion. By use of path analysis, the genetic variance of measured peak O2 uptake was estimated at 77% (P less than 0.001), at 71% (P less than 0.001) after adjustment for weight and skinfold thickness, and at 66% (P less than 0.001) after additional adjustment for weekly hours of sports participation. O2 uptake at a heart rate of 150 beats/min, a submaximal estimate of exercise capacity, showed less genetic variance, i.e., 61% (P less than 0.001) before and 50% (P less than 0.001) after weight adjustment and only 16% (NS) after correction for life-style factors. Similarly, the heritability of peak O2 uptake, when estimated from submaximal data, was 68% (P less than 0.001), 40% (P = 0.05), and 26% (NS), respectively. Mechanical efficiency had no significant genetic component. O2 uptake at the respiratory exchange ratio of 0.95 and the slope of the curvilinear relationship between CO2 output and O2 uptake, used to assess the anaerobic energy generation during progressive exercise, showed significant (P less than 0.001) genetic variance before (72 and 74%) and after adjustment for weight (67 and 69%) and sports participation (63 and 57%). The heritability of peak aerobic power remained significant (58%; P less than 0.001) after adjustment for these expressions of anaerobic energy generation. In conclusion, the genetic variance of measured peak O2 uptake is significant and persists after adjustment for anthropometric characteristics, life-style factors, anaerobic energy generation, and mechanical efficiency.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[Hemodynamic effects of urapidil in men].

In hypertensive patients as well as in normal subjects, urapidil has a hypotensive action. This is mainly mediated by a peripheral alpha adrenoceptor blockade with a decrease in systemic vascular resistance. In addition, acute animal experiments demonstrated a centrally mediated hypotensive action, possibly by 5-hydroxytryptamine1A-receptor stimulation. Studies in humans showed an increase in cardiac output, which was not always significant; it resulted either from an increased heart rate or an increased stroke volume. Acute changes in pulmonary hemodynamics after administration of urapidil were most pronounced in patients with pulmonary hypertension: pulmonary artery pressure and pulmonary vascular resistance decreased significantly and pulmonary capillary wedge pressure decreased non-significantly. A small reduction in pulmonary artery pressure and capillary wedge pressure was seen in patients with congestive heart failure and in patients in whom acute blood pressure elevation developed after coronary bypass surgery. In patients with essential hypertension, forearm, renal and splanchnic flows were shown to increase and vascular resistance to decrease significantly after an acute intravenous doses of urapidil. The hemodynamic changes that occur during chronic therapy are largely unknown, except for systemic vascular resistance which remains decreased.

Antihypertensive Agents↗
PubMed1990

Inheritance of heart structure and physical exercise capacity: a study of left ventricular structure and exercise capacity in 7-year-old twins.

The maximal aerobic power of endurance athletes is high and their heart is characterized by a larger left ventricular internal dimension than in non-athletes, and a proportional increase of wall thickness; these traits may be inherited and/or the consequence of intense physical training. To assess the influence of inheritance on physical exercise capacity and on echocardiographically determined cardiac structure, and to limit the effect of environmental factors as much as possible, we studied 15 monozygotic and 19 dizygotic 6- to 8-year-old twin pairs. Exercise capacity was expressed as the times at which the heart rates of, respectively, 150 and 170 beats min-1 were reached during a progressive exercise test on the treadmill. For these exercise times the within-pair variance was significantly larger in dizygotic compared with monozygotic twins. Therefore significant genetic variance was inferred, both when the exercise times were expressed as absolute values and after adjustment for body weight and gender. As for cardiac structure at rest, the results did not suggest a significant influence of genetic endowment on left ventricular internal diameter or on wall thickness; genetic variance was significant, however, for calculated left ventricular mass (P less than 0.05) and left ventricular mass adjusted for body weight and gender. The results are compatible with the notion that the high aerobic power of endurance athletes is at least partly inherited. Left ventricular internal dimension and wall thickness, which distinguish an athlete's heart at rest from the heart of a non-athlete, do not show a significant genetic component, suggesting that the qualities characteristic of an athlete's heart, at least as assessed at rest, are not inherited. The inheritance of aerobic power may be due to inheritance of non-cardiac factors or to cardiac features which are only expressed during exercise.

Blood Pressure↗
PubMed1989

Urapidil-induced hemodynamic changes in humans.

In hypertensive patients as well as in normal subjects urapidil has a hypotensive action. This is mainly mediated by a peripheral alpha 1-adrenoceptor blockade with a decrease in systemic vascular resistance; in addition, during acute animal experiments a centrally mediated hypotensive action was demonstrated, possibly by 5-hydroxytryptamine1A (5-HT1A)-receptor stimulation. Studies in humans showed an increase in cardiac output, which was not always significant; it did result either from an increased heart rate or an increased stroke volume. Acute changes in pulmonary hemodynamics after administration of urapidil were most pronounced in patients with pulmonary hypertension: pulmonary artery pressure and pulmonary vascular resistance decreased significantly and pulmonary capillary wedge pressure decreased nonsignificantly. A small reduction in pulmonary artery pressure and capillary wedge pressure were seen in patients with congestive heart failure and in patients in whom acute blood pressure elevation developed after coronary bypass surgery. In patients with essential hypertension forearm, renal and splanchnic flow were shown to increase and vascular resistance to decrease significantly after acute intravenous doses of urapidil. The hemodynamic changes during chronic therapy are largely unknown, except for systemic vascular resistance which remains decreased.

Acute Disease↗
PubMed1989

Converting enzyme inhibitors in the treatment of elderly hypertensives.

Angiotensin-converting enzyme inhibitors are gaining acceptance as safe and effective agents for treatment of hypertension. Addressed in this review of the available literature are the questions whether they are effective in lowering blood pressure in the elderly, whether their effects are age-related, and what effects, if any, do they have on morbidity and mortality in geriatric hypertension.

Aged↗
PubMed1988

The effect of ageing on the plasma renin-angiotensin-aldosterone system in elderly hypertensive patients.

Plasma renin activity, renin concentration and aldosterone concentration were measured in 78 untreated hypertensive patients aged 60-83 years. In a cross-sectional analysis, plasma renin activity, renin concentration and aldosterone concentration showed no relationship with age. Half of these patients were subsequently followed on placebo over a 3-year period during which the plasma constituents of the renin-angiotensin-aldosterone system remained stable. From these cross-sectional and longitudinal observations we conclude that beyond the age of 60 ageing has no detectable effect on plasma renin and aldosterone levels in these elderly hypertensive patients.

Aged↗
PubMed1987

Maximum oxygen uptake and cardiac size and function in twins.

The contribution of heredity to the interindividual variability of maximum oxygen uptake and of cardiac size and function of healthy male twins, age 18 to 31 years, was studied to evaluate the role of the heart in the inheritance of aerobic power. Twelve pairs of monozygotic and 12 pairs of dizygotic twins were examined. Weight (p less than 0.05), relative weight (Quetelet index) (p less than 0.01) and skinfold thickness (p less than 0.01) were found to be genetically determined, as well as heart rate at rest (p less than 0.05) and systolic blood pressure (p less than 0.05). Genetic variation was significant (p less than 0.05) both for absolute and for weight-adjusted oxygen uptake, measured at peak exercise on the bicycle ergometer. However, the influence of inheritance on aerobic power was not associated with a significant genetic effect on the end-diastolic left ventricular internal diameter or on its fractional shortening as assessed by echocardiography. Genetic variation had a significant (p less than 0.05) effect on left ventricular mass, but this could be attributed to the inheritance of body size. These data indicate that cardiac factors are not significantly involved in the inheritance of aerobic power and suggest that cardiac hypertrophy in athletes is secondary to training.

Adolescent↗
PubMed1987

Assessment of stiffness of the hypertrophied left ventricle of bicyclists using left ventricular inflow Doppler velocimetry.

Sixteen male bicyclists and 16 control subjects were studied to assess whether the left ventricular hypertrophy of athletes is associated with changes in diastolic left ventricular function. The cyclists had a larger left ventricular internal diameter on echocardiography (55.2 versus 47.9 mm; p less than 0.001) and a disproportionate increase in wall thickness relative to the internal diameter (0.48 versus 0.41; p less than 0.01), indicating a mixed eccentric-concentric type of hypertrophy. Left ventricular inflow Doppler velocimetry showed similar results in athletes and control subjects for peak flow velocities in the atrial contraction phase (30 versus 32 cm/s; p = NS) and in the early diastolic rapid filling phase (71 versus 67 cm/s; p = NS). The similar ratio of both velocities, that is, 0.43 in the cyclists and 0.49 in the control subjects, suggests that left ventricular distensibility is unaltered in cyclists. It is concluded that the left ventricular hypertrophy observed in cyclists is not associated with changes in ventricular stiffness, as estimated from left ventricular inflow Doppler velocimetry.

Adolescent↗