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Biomedical subjects

D Duprez

Publications and source records attributed to D Duprez.

At least 73 records · Page 4Linked to original sources
PubMed1994

Antihypertensive effects of calcium antagonists. Clinical facts and modulating factors.

There is no doubt that calcium antagonists are effective antihypertensive agents. Their antihypertensive potency is comparable with that of beta-blockers and angiotensin-converting enzyme inhibitors. Blood pressure decreases are dose dependent with no orthostatic reactions, and are more pronounced in patients with lower renin levels, which is demonstrable in both white and black patients; whether the blood pressure response is stronger in elderly patients remains to be ascertained. Blood pressure rises during stress are moderately decreased. Basic documentation has been obtained for first-generation calcium antagonists, and the newer members of this class of drugs--nearly all dihydropyridine derivatives--were developed to achieve greater vascular specificity and a longer duration of action. With calcium antagonists, blood pressure decreases are due to decreases in peripheral resistance. However, blood flow increases do not necessarily persist over time, thus raising the question of what is the mechanism for the long-term decreases in blood pressure. Several studies have shown that blood pressure variability is unchanged with calcium antagonists. However, blood pressure decreases are accompanied by regression of left ventricular hypertrophy, which is understandable in light of the strong correlation between parathyroid hormone and left ventricular hypertrophy. The use of calcium antagonists in the treatment of clinical hypertension can be guided by the following facts: 1) They are metabolically neutral and are accompanied by few or no life-threatening side effects that, when they do occur, tend to disappear over time; 2) They increase blood flow to muscle and help control angina pectoris as well as vasospastic diseases.

Antihypertensive Agents↗
PubMed1994

Relationship between vitamin D3 and the peripheral circulation in moderate arterial primary hypertension.

Although altered cellular calcium handling plays a critical role in the pathophysiology of hypertension, little attention has been focused on the impact of calcium regulating hormones on target-organs (e.g. vascular tissue). Therefore the relationship between calcium, phosphorus, parathyroid hormone, 25- and 1,25-(di) hydroxyvitamin D3, blood pressure (BP) and regional circulation was examined in 25 patients (44 +/- 2.5 years) with moderate hypertension (systolic BP 164 +/- 4 mmHg, diastolic BP 105 +/- 2 mmHg). Calf and finger blood flow were measured simultaneously using ECG-triggered plethysmography at rest and after 3 min arterial occlusion (reactive hyperemia). Systolic and diastolic BP were inversely correlated with 25-hydroxyvitamin D3 (r = -0.511 and r = -0.445, p < 0.002). Calf vascular resistance at rest (r = -0.46, p = 0.02) and after 3 min arterial occlusion (r = -0.78, p = 0.0001) was related to 25-hydroxyvitamin D3 concentration. Only calf vascular resistance during reactive hyperemia was significantly related to 1,25-dihydroxyvitamin D3 (r = -0.44, p = 0.03). After correction for blood pressure calf vascular resistance after 3 min arterial occlusion remained significantly and inversely related with 25-hydroxyvitamin D3. There was no relation between finger (skin) circulation and vitamin D3. All other calcium regulating factors were unrelated to the parameters of peripheral circulation. Our results indicate that among the calcium regulating factors, particularly vitamin D3 seems to inversely influence muscle, but not skin vascular tone-independently of blood pressure in mild to moderate hypertension.

Adult↗
PubMed1993

Coagulation system activation and increase of D-dimer levels in peripheral arterial occlusive disease.

The aim of the present study was to document coagulation system activation and basal fibrinolysis in peripheral arterial occlusive disease (PAOD) at stage II of Fontaine's classification. In 34 patients, prothrombin fragment (F1 + 2), thrombin-antithrombin III complexes (TAT), and D-dimer concentrations were evaluated before and after a standard treadmill test. Basal levels in PAOD of F1 + 2 (1.25 +/- 0.19 nmol/liter) and of TAT (3.34 +/- 0.35 micrograms/liter) were significantly increased compared to those obtained in age- and sex-matched healthy controls (0.68 +/- 0.06 nmol/liter and 2.30 +/- 0.33 micrograms/liter, respectively), showing baseline activation of the clotting cascade. A secondary activation of the fibrinolytic system was evidenced by the highly significant increase of basal D-dimers (719 +/- 99 ng/dl in PAOD vs. 229 +/- 37 ng/dl in controls). Treadmill exercise failed to increase the study parameters significantly further. Walking distance (583 +/- 40 m) was correlated with the preexercise ankle to brachial systolic blood pressure ratio (r = 0.485, P < 0.005) and inversely with the level of D-dimers (r = -0.425, P < 0.02). Under baseline conditions, the latter parameter was correlated as well with the antigen concentration of urokinase-type plasminogen activator (u-PA; r = 0.503, P < 0.002). These results indicate that stage II PAOD is characterized by an activation of the clotting cascade in baseline conditions evidenced by increased F1 + 2 and TAT. A secondary activation of the fibrinolytic system with increased u-PA antigen levels accounts for the elevated D-dimers. Treadmill exercise was unable to increase these parameters further.

Aged↗
PubMed1993

Cardiac anatomy and diastolic filling in professional road cyclists.

In the literature two divergent types of exercise-induced cardiac hypertrophy have been described: isotonic exercise induced eccentric hypertrophy with proportional increase in end-diastolic left ventricular dimension and wall thickness and isometric exercise induced concentric hypertrophy with normal end-diastolic left ventricular dimension but increased wall thickness. Using echocardiography, cardiac anatomy and diastolic filling were studied in 26 professional road cyclists. Compared to 21 control subjects, matched according to age, sex and morphometry the athletes had significantly larger left atrial dimension [41.3 (SD 4.8) vs 36.6 (SD 4.5) mm], left ventricular dimension [56.0 (SD 3.8) vs 53.2 (SD 4.7) mm], end-diastolic septum thickness [11.1 (SD 2.5) vs 8.4 (SD 1.9) mm], end-diastolic posterior wall thickness [11.6 (SD 2.2) vs 8.4 (SD 1.5) mm] and left ventricular mass index [170.4 (SD 40.6) vs 107.0 (SD 27.7) g.m-2]. We concluded that the hypertrophy in the road cyclists was of the mixed type (concentric-eccentric) with an increase in the internal dimension of the left ventricle and an even larger increase in the thickness of the ventricular walls. Diastolic filling however was similar in the athletes and control subjects. No correlations were found between the left ventricular mass index and diastolic filling parameters. We concluded therefore that professional road cycling causes mixed cardiac hypertrophy without diastolic filling abnormalities and can therefore be considered benign.

Adult↗
PubMed1993

Influence of isosorbide dinitrate on superior mesenteric artery impedance in humans.

In a randomized, double-blind, placebo-controlled crossover study the acute effect of isosorbide dinitrate (ISDN) on the superior mesenteric artery velocity waveform was studied in 10 healthy subjects (mean age 48.2 years) over a 10-minute period. The superior mesenteric artery pulsatility index (PI), which quantifies the blood velocity waveform, increased from the second minute following sublingual administration of 5 mg ISDN (basal PI 4.88 +/- 0.32) and reached its upper level (8.22 +/- 1.38) from the fourth minute on. In comparison with placebo, the significant rise of PI (second minute) occurred before the significant decrease of systolic blood pressure (ninth minute) and before the significant increase in the heart rate (fourth minute). Diastolic and mean arterial blood pressures remained unchanged. These observations suggest an immediate vasoconstrictive effect of ISDN on the resistance vessels of the vascular bed of the superior mesenteric artery.

Aged↗
PubMed1993

Peripheral vascular changes and ambulatory blood pressure profiles.

This study aimed to correlate blood pressure (BP) level assessed either by casual or by 24-h ambulatory BP monitoring and regional (calf and finger) blood flow and associated vascular resistance in subjects with low, intermediate, and high BP. In 75 subjects covering the range from low BP to normo- and hypertension, blood flow at calf and finger vessels were simultaneously measured using an ECG-triggered venous occlusion plethysmograph. Correlations were calculated between regional blood flow or vascular resistance and BP defined from casual and from 24-h ambulatory BP registrations, at rest, and after 3 min of arterial occlusion (reactive hyperemia). Correlations over the whole BP range, between calf and finger vascular resistances and BP, were highly significant both for casual (0.650 < r < 0.776) and for ambulatory (0.531 < r < 0.781) BP. The relations remained significant after adjustment for the age dependency of the blood pressure. At any BP level skin (finger) blood flow at rest and after arterial occlusion was higher than muscle (calf) blood flow. These data indicate that there is a progressive decrease in vasodilating capacity from low to high BP in both muscle and skin vessels. However, in the zone of borderline to moderate essential hypertensives, blood flow after 3 min arterial occlusion was already significantly decreased in the muscle circulation when compared to normotensives, while still maintained in the skin circulation.

Adult↗
PubMed1993

Left ventricular function and regression of left ventricular hypertrophy in essential hypertension.

Although left ventricular hypertrophy (LVH) is an adaptive response to the increased load imposed on the heart in patients with hypertension, it ultimately is itself a major risk factor for cardiovascular disease. The influence of LVH on left ventricular function and on the coronary circulation, and the occurrence of serious ventricular arrhythmias are the major mechanisms of this increased risk. There is no doubt that regression of LVH occurs, but there are clear differences in this respect among antihypertensive drugs: angiotensin-converting enzyme (ACE) inhibitors and calcium antagonists produce the best response. Whether regression of LVH also causes an improvement in left ventricular function is unclear; various studies using the same drugs have yielded contradictory results. Furthermore, it has yet to be determined whether regression of LVH has a positive influence on the long-term prognosis in such patients; the results of the European Multicenter Study OvA will help in shedding more light on this important question.

Antihypertensive Agents↗
PubMed1993

Myocardial oxygen demands of job activities in post-myocardial infarct patients.

In 17 patients who returned to work following rehabilitation after an uncomplicated acute myocardial infarction (AMI), the myocardial oxygen demands (MOD) of various job activities were assessed using discontinuous ambulatory heart rate (HR) and blood pressure measurements. All patients were on beta-blocking agents. HR and rate-pressure product (RPP) reserves were calculated as the differences between maximal values observed during a symptom-limited maximal bicycle exercise test and basal values. Basal values were either pre-test resting values or mean values from night-time registrations between 0100h and 0500h. Night-time values of basal HR and RPP were 7.7 and 18.7% lower respectively as compared to pre-test resting values. The myocardial energy demands of various job activities were calculated as the percentage use of the reserves. This resulted in lower MOD estimations when pre-test values were used as compared to night-time values. These differences were larger for the estimation of MOD of light physical work (mean difference 25%) than for heavy physical work (mean difference 12%). The estimations of MOD using HR reserve or RPP reserve were very similar. In patients who performed the same job activities no correlation was found between MOD and left ventricle ejection fraction. We believe these data provide useful information about the functional capacity of AMI patients. They also emphasise the great importance that has to be attached to the definition of basal values.

Adrenergic beta-Antagonists↗
PubMed1993

Is vascular disease in the female different from men?

Therapeutical management of cardiovascular disease has been based on the results from clinical trials of which the majority of the included patients are men. There is now more evidence that risk factors for female cardiovascular patients are different than for male patients. There is even a sex difference in the management of cardiovascular disease in general. Retrospective studies have shown a beneficial effect of postmenopausal hormone replacement therapy on the reduction of cardiovascular morbidity and mortality and stroke as well. However, there are conflicting data in the literature and prospective studies are necessary. More attention has to be paid to cardiovascular disease in the female and studies of precise circulatory differences between sexes are recommended.

Aged↗
PubMed1993

On the relationship between regional circulation and systemic blood pressure.

OBJECTIVES: The relationship between regional circulation (blood flow or calculated resistance) and systemic blood pressure (BP) is only poorly documented in the range of intermediate to low BP. METHODS: In 75 subjects covering the BP range from low, over intermediate, to high BP, venous occlusion plethysmographic recordings were performed at the calf and finger vessels. Correlations were calculated between regional blood flow or vascular resistance and BP defined from office and from 24 h ambulatory BP registrations, at rest and during reactive hyperaemia. RESULTS: At any BP level, finger blood flow at rest and during reactive hyperemia was higher than calf blood flow, and resistance was lower. The interval of 90-100 mmHg office diastolic BP was characterized by significantly (p < 0.001) higher resting finger blood flow; the increase in resting muscle blood flow was less pronounced. At rest and during reactive hyperaemia there was a stepwise increase in calf regional vascular resistance in parallel with increasing BP. For the finger circulation, increased vascular resistance was only observed for the higher BP values. Correlations between calf and finger vascular resistances and BP were positive and highly significant over the whole BP range, both for office (0.650 < r < 0.776) and for ambulatory BP (0.531 < r < 0.781). These correlations remained significant after adjustment for the age dependency. Increases in calf and finger blood flow induced by arterial occlusion were highest for the lowest BP quintiles. CONCLUSIONS: Our data further indicated that the capacity to dilate decreased progressively with increasing BP level (from asymptomatic low to high BP) for both calf and finger circulation.

Adult↗
PubMed1993

Localization of RIHB (retinoic acid-induced heparin-binding factor) transcript and protein during early chicken embryogenesis and in the developing wing.

Previously, we isolated an avian protein which we named retinoic acid induced heparin binding factor (RIHB). RIHB is a 121 amino acid secreted polypeptide, rich in basic and cysteine residues (Vigny et al., Eur. J. Biochem. 186: 733-740, 1989). Northern blot analysis indicates that the RIHB gene is transiently expressed during embryogenesis (Urios et al., Biochem. Biophys. Res. Com. 175:617-624, 1991). Here we present an investigation of RIHB expression during early chicken embryogenesis by in situ hybridization and immunofluorescence studies. In the 3-day embryo (stage 20-21), the RIHB transcript is observed throughout the embryo, with the notable exception of the neural tube. At this stage the protein can be visualized in almost all of the basement membranes and around many types of cells. The localization of the RIHB protein does not strictly parallel that of its messenger. Between days 3 and 11 we focused our attention on wing development. The level of both the mRNA and protein decreases during this period but the disappearance is not uniform. The level of both the mRNA and protein decreases during this period but the disappearance is not uniform. The transcript becomes progressively restricted to epithelia and regions surrounding the forming cartilage. In contrast to the transcript, the protein accumulates in the epithelial basement membrane and, interestingly, in the central part of the embryonic cartilage (diaphysis) but not in the distal parts (epiphysis). These data are discussed in relation to the putative role(s) of RIHB in development.

Animals↗
PubMed1992

Comparison of lisinopril and nitrendipine on the pulsatility index in mild essential arterial hypertension.

A double-blind, randomized crossover study was performed in 21 patients with essential arterial hypertension. Nitrendipine 20 mg o.d. and lisinopril 20 mg o.d. were given in a randomized order during a period of each 8 weeks. Nitrendipine and lisinopril decreased systolic and mean arterial blood pressure to a similar level without a significant increase in heart rate. The mean diastolic blood pressure was smaller with the lisinopril treatment than with the nitrendipine treatment. The blood pressure decrease was maintained in the sitting and standing position. Furthermore, only nitrendipine decreased the pulsatility index at the tibial posterior arteries, while lisinopril did not influence it significantly. This finding means that mechanisms other than the blood-pressure lowering effect are involved in the decrease of the pulsatility index.

Adult↗
PubMed1992

Investigation of a possible pharmacokinetic interaction between ibopamine and isosorbide-5-mononitrate.

The possibility of a pharmacokinetic interaction between isosorbide-5-mononitrate (5-ISMN) and epinine, the active metabolite of ibopamine, has been investigated in 8 healthy male subjects given single doses of 200 mg ibopamine and 20 mg 5-ISMN, separately and together. The plasma 5-ISMN concentration-time profile was the same whether 5-ISMN was administered concomitantly with ibopamine or alone [AUC(o-t): 2.24 micrograms.ml-1.h after 5-ISMN alone, 2.16 micrograms.ml-1.h after 5-ISMN+ibopamine]. The plasma concentrations of total and free epinine and the urinary recovery of total epinine, homovanillic acid and dihydroxyphenylacetic acid, too, were not different when ibopamine was administered alone or concomitantly with 5-ISMN. The intake of ibopamine did not change the blood pressure and heart rate. The decrease in diastolic blood pressure induced by 5-ISMN was not influenced by concomitant intake of ibopamine. The observations suggest that in healthy volunteers there is no pharmacokinetic interaction between 5-ISMN and ibopamine.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1992

Blood pressure load determines left ventricular mass in essential hypertension.

In a series of 35 newly diagnosed, previously untreated patients (mean age 46 years) with mild to moderate essential hypertension, office blood pressure measurements, 24-hour ambulatory blood pressure monitoring, and determination of left ventricular mass index by echocardiography according to the formula of Devereux were performed. We aimed at correlating left ventricular mass index with systolic and diastolic office blood pressure, mean 24-hour systolic and mean 24-hour diastolic blood pressure, systolic and diastolic load. Left ventricular mass index did not correlate with office systolic and office diastolic blood pressure. On the contrary, all correlations with ambulatory blood pressure parameters and left ventricular mass index turned out to be significant (mean 24-hour systolic blood pressure: r = 0.344, P = 0.026; systolic load: r = 0.408, P = 0.020; mean 24-hour diastolic blood pressure: r = 0.490, P = 0.004; diastolic load: r = 0.504, P = 0.003). These results clearly demonstrate that ambulatory blood pressure determinants but not the office blood pressure parameters are well correlated with left ventricular mass index in mild to moderate essential hypertension. Blood pressure load is as important as mean 24-hour blood pressure in this regard.

Adult↗
PubMed1992

Right atrial invasive thymoma with protrusion through the tricuspid valve.

A patient with superior caval vein compression due to malignant thymoma with infrequent intracavitary cardiac growth is presented. Diagnostic accuracy of cardiac involvement was higher using transesophageal echocardiography compared to transthoracic echocardiography. The majority of the rare intracavitary cardiac thymomas seem to be confined to the right side of the heart.

Aged↗