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Biomedical subjects

P L Milliez

Publications and source records attributed to P L Milliez.

At least 19 recordsLinked to original sources
PubMed1981

Central haemodynamics and plasma prostaglandin E2 in borderline and sustained essential hypertensive patients before and after indomethacin.

1. In basal conditions, plasma arterial prostaglandin (PG) E2 was significantly increased in borderline hypertensive patients (BH) (28.5 +/- 6.7 pg/ml) in comparison with sustained essential hypertensive patients (EH) (11.6 +/- 3.2 pg/ml) and in comparison with control normotensive subjects (NTS) (5.8 +/- 1.4 pg/ml). 2. Plasma arterial PGE2 was positively significantly correlated with cardiac index and negatively significantly correlated with total peripheral resistance in basal conditions. 3. Indomethacin induced more pronounced haemodynamic changes in borderline than in sustained hypertensive patients, with a significant increase in arterial blood pressure and total peripheral resistance and a significant decrease in stroke volume and cardiac index. 4. Indomethacin significantly decreased arterial PGE2 in borderline hypertensive patients. The decrease was less important in sustained hypertensive patients. 5. In the overall population, a significant positive correlation between arterial PGE2 concentration and cardiac index was observed before and after indomethacin treatment. 6. The study suggests an important role of PGE2 in the regulation of cardiac output (positive inotropic effect) and blood pressure of essential hypertensive patients.

Adult↗
PubMed1981

Influence of previous diuretic intake on the humoral and hormonal profile of idiopathic oedema.

Three groups of women underwent water loading tests: normal subjects, idiopathic oedema patients who had taken no medication for at least 3 months, and a second oedema group with recent diuretic intake. Idiopathic oedema in drug-free patients was characterized by an abnormal capillary permeability, lower basal protein values, a dramatic drop in urinary output in the upright position due to reduced glomerular filtration, enhanced reabsorption of sodium and water and stimulation of aldosterone and antidiuretic hormone (AVP) secretions. In these idiopathic oedema cases, osmolar AVP regulation was disrupted but AVP control by plasma volume was maintained. In the basal state, patients with recent diuretic intake were characterized by a gain in body weight and by depletion of plasma volume and plasma potassium. In these subjects, urinary output in the upright posture was as insufficient as in drug-free patients but was due to higher sodium reabsorption. Renal insensitivity to AVP action was also observed. Osmolar regulation and volume regulation of AVP were both disrupted in these cases with recent diuretic intake.

Adult↗
PubMed1979

Guanfacine kinetics in patients with hypertension.

Guanfacine kinetics were studied in 19 patients with hypertension after single and repeated oral doses. The single-dose study was performed in two homogeneous groups who received 2 mg (n = 9) and 4 mg (n = 10). The plasma concentrations were fitted in a two-compartment open model with first-order absorption. After a lag time of 0.8 hr, the absorption occurred rapidly (t 1/2 congruent to 0.53 hr). The fast and slow elimination phases occurred with t 1/2s of 2 and 19 hr. At therapeutic levels the percent of drug in red blood cells (55%) was independent of total drug concentration. Peak plasma levels had small interindividual variations. Comparison of kinetic parameters and AUC at the two doses studied demonstrated that their bioavailability was equal and the kinetics were linear. In a multiple-dosing study, performed in the same subjects, the plasma levels at steady state were in good agreement with the predicted values (p less than 0.001) and proportional to daily dosage. A single method based on four blood samples collected after 24, 28, 32, and 36 hr allows a reasonable prediction of the effective steady-state plasma levels during chronic dosing with guanfacine.

Adult↗
PubMed1977

Pindolol availability in hypertensive patients with normal and impaired renal function.

Intravenous and oral pharmacokinetics of pinlolol were studied in 18 hypertensive patients-9 with normal renal function and 9 with impaired renal function. Analysis of data showed that a linear two-compartment model was suitable to describe the pindolol kinetics. Compared with patients with normal renal function, patients with chronic renal failure exhibited: (1) unchanged transfer rate constants and distribution volumes and (2) decreased total body clearance with decreased renal clearance and unchanged nonrenal clearance. Analysis of oral data by the Loo-Riegelman method showed that the pindolol absorption kinetic was not first order. Compared with patients with normal renal function, patients with chronic renal failure exhibited decreased fraction of dose effectively absorbed and increased initial rate of absorption. The initial rate of absorption was inversely correlated with the creatinine clearance. The study disclosed evidence that absorption was modified in chronic renal failure.

Administration, Oral↗
PubMed1977

Volume-dependent parameters in essential hypertension.

Blood pressure, renal blood flow, total blood volume (TBV), plasma renin activity, and vascular reactivities to angiotensin and norepinephrine were studied in 48 normotensive subjects and 106 essential, sustained, hypertensive patients with normal renal function, balanced sodium intake, and urinary output. A significant negative pressure-volume relationship was observed in normal subjects. Among the hypertensive patients, some were inside the 95% confidence limits of the normal curve and the others were above, indicating a disturbance in the pressure-volume relationship. A quantitative evaluation of the pressure-volume disturbance was proposed and discussed. The blood pressure of each hypertensive patient corresponded to two different blood volume values: the renal valve and the theoretical value extrapolated from the normal curve. The difference between the two values was called deltaTBV and was positive in hypertensive patients. The deltaTBV value was negatively correlated with the renal blood flow, the creatinine clearance, the plasma renin activity, and the vascular reactivities to angiotensin and norepinephrine (P less than 0.0001). The parameters were not correlated with the real blood volume. This study demonstrates quantitatively a pressure-volume disturbance in essential hypertension. This disturbance is strongly correlated with the renal function and the renin-angiotensin system changes.

Blood Pressure↗
PubMed1977

Baroreflex sensitivity and cardiopulmonary blood volume in normotensive and hypertensive patients.

Baroreflex sensitivity and cardiopulmonary blood volume were determined in 95 men, including normotensive and hypertensive subjects with normal renal function and balanced sodium intake and urinary output. Baroreflex sensitivity was estimated by determining the slope of the regression line relating the increase of systolic pressure to the cardiac slowing after transient rises of arterial pressure. A technique of gradual atropinisation was used to evaluate the parasympathetic mediated component of the reflex. With this method, it was possible to calculate the exact atropine dose abolishing the reflex sensitivity. This index was not dependent on age. It was negatively correlated to the diastolic pressure in normotensive patients but not in hypertensive patients. The ratio between the cardiopulmonary and the total blood volume was considered as an index of sympathetic venous tone. This ratio was positively correlated to the diastolic pressure in normotensive patients, but not in hypertensive patients. This study strongly suggests that a precise sympathetic-parasympathetic balance existed in the normotensive patients. This balance was disrupted in the hypertensive patients pointing to abnormalities in the autonomic nervous system of permanently hypertensive patients.

Adult↗
PubMed1977

Central hemodynamics and cardiac output control in essential hypertensive patients.

Central hemodynamics were determined in 202 men including 101 normotensive and 101 permanent essential hypertensive patients of the same age. Cardiac output was identical in the two groups while blood pressure and total peripheral resistance were significantly different. Strong differences between the two groups are revealed by a systematic correlation study: (i) correlations of blood pressure (with respectively heart rate and total blood volume) were significant in the normotensive group but not in the hypertensive group; (ii) correlations of cardiac output (with respectively heart rate and total blood volume) were significant in both groups; (iii) correlations of renal blood flow (with respectively cardiac output and blood pressure) were significant in the hypertensive group but not in the normo tensive group. This study provided evidence that the volume and neural pressure controls are impaired in hypertensive patients while the cardiac output control is maintained and, suggested the existence of adaptive mechanisms involving the kidney in the maintenance of normal cardiac output in permanent essential hypertensive patients.

Adaptation, Physiological↗
PubMed1977

Relationship of plasma renin activity and aldosterone levels with hemodynamic functions in essential hypertension.

Correlates of plasma renin activity and plasma aldosterone levels with hemodynamic functions were studied in 47 male patients with untreated, permanent essential hypertension. All subjects had a normal creatinine clearance and received a diet of 110 mEq/day of sodium. Supine plasma renin activity was directly correlated with cardiac index (P less than.01) and cardiopulmonary blood volume (P=.01). Percentage changes in plasma renin activity and total peripheral resistance in response to upright position were positively correlated (P less than.001). Supine plasma aldosterone level was directly correlated with stroke index (P less than .001) and negatively correlated with hear rate (P less than .05). No significant correlation of aldosterone level was observed with the other measurements, including plasma renin activity. The study points to the neural sympathetic control of plasma renin activity in essential hypertension and suggests the existence of some interrelationships between aldosterone level and cardiac performance.

Adult↗
PubMed1976

[A new approach of the hemodynamics of human essential hypertension. Study of the control of cardiac output].

The smoothing technique is used in this part II to study the cardiac output control in normotensive and hypertensive subjects. It is proved that: 1. cardiac frequency and total blood volume are both determinants of cardiac output in the normotensives; 2. in the hypertensives, blood volume is the main factor, the role of the frequency becomes negligible; 3. at high pressures, the part of the blood volume in the body-weight increases, suggesting an overhydration phenomenon in essential human hypertension.

Blood Volume↗
PubMed1976

Isoproterenol sensitivity and total body clearance of propranolol in hypertensive patients.

The isoproterenol sensitivity (dose-response curve) and the total body clearance of propranolol were measured in 80 men including 15 normal subjects and 65 essential hypertensive patients (20 borderline and 45 permanent hypertensives). The critical dose of isoproterenol was found to be directly correlated to weight (P less than 0.01), age (P less than 0.001), and basal diastolic arterial pressure (P less than 0.001). A partial correlation coefficient study showed that the diastolic arterial pressure was of greater influence than weight and age. The total body clearance of propranolol was inversely related to the basal diastolic arterial pressure (P less than 0.0001) in hypertensive patients. The study provides evidence that the level of basal diastolic arterial pressure could influence the beta-receptor responsiveness and the beta-adrenergic blockade in hypertensive patients.

Adult↗
PubMed1976

Control of cardiac output in essential hypertension.

Cardiac and renal hemodynamics and cardiopulmonary and total blood volume were determined in 202 men, 101 with normotension and 101 of the same age with chronic essential hypertension, normal renal function and balanced sodium intake and urinary output. Cardiac output was identical in the two groups, whereas blood pressure and total peripheral resistance were significantly different. The two groups exhibited strong differences in the correlation study: (1) Correlations of blood pressure with, respectively, heart rate, cardiopulmonary blood volume and total blood volume were significant in the normotensive group but not in the hypertensive group. (2) Correlations of cardiac output with, respectively, heart rate, cardiopulmonary blood volume and total blood volume were significant in both groups. (3) Correlations of renal blood flow with, respectively, cardiac output, blood pressure and total blood volume were significant in the hypertensive group but not in the normotensive group. This study provides evidence that: (1) the volume and neural control of blood pressure are disrupted in hypertension whereas control of cardiac output is maintained; and (2) adaptive mechanisms involving renal function are necessary to the maintenance of normal cardiac output in patients with essential hypertension.

Adult↗
PubMed1976

The spectrum of pressor-response to norepinephrine in normotensive and hypertensive patients.

The pressor-response to norepinephrine was determined in the whole body circulation of 15 normal subjects and 86 untreated essential hypertensive patients. The slope, the threshold-dose and the critical-dose were calculated from the log dose-response curve. In the overall population (101 subjects) a slight correlation (r = +0.20 less than 0.05) was observed between the basal diastolic arterial pressure and the threshold-dose. In contrast, highly significant parabolic correlations (r = +0.46 less than 0.00001) were observed between the diastolic arterial pressure and the slope or the critical dose. When diastolic arterial pressure was above 100 mmHg, the slope increased while the blood pressure increased. This result suggests either a decreased sympathetic tone or an adaptative structural change of the arterial wall. When diastolic arterial pressure was under 100 mmHg, the slope decreased while the blood pressure increased. This observation points to an enhanced sympathetic activity in mild blood pressure.

Adult↗
PubMed1975

Vascular reactivity to norepinephrine and hemodynamic parameters in borderline hypertension.

Pressor response to norepinephrine, cardiopulmonary blood volume, and hemodynamic parameters were studied in 41 borderline hypertensive patients in comparison with 42 permanent essential hypertensive patients and 28 normal subjects. Borderline hypertensive subjects had high cardiac index (p less than 0.0001), normal total peripheral resistance, and low total blood volume (p less than 0.005). The ratio between cardiopulmonary blood volume (CPBV) and total blood volume (TBV) was significantly higher in comparison with normal subjects (p less than 0.01) and permanent hypertensive subjects subjects (p less than 0.0001). The pressor dose of norepinephrine was elevated (p less than 0.0001) and was directly correlated with the basal values of the cardiac output (p less than 0.005), the cardiopulmonary blood volume (p less than 0.001), and the CPBV/TBV ratio (p less than 0.01). None of these results was observed in permanent hypertensive subjects: the only significant result was a negative correlation between the pressor dose of norepinephrine and the basal diastolic arterial pressure (p less than 0.0001). This study provides evidence that the cardiac output elevation in borderline hypertensive subjects was related to increased venous return and enhanced sympathetic venous tone.

Adult↗
PubMed1975

Altered blood volume regulation in sustained essential hypertension: a hemodynamic study.

Cardiac and renal hemodynamics and total blood volume were determined in 28 normal subjects and 60 patients with untreated essential well-established hypertension. Endogenous creatinine clearance was within normal ranges and sodium intake was 110 mEq/day. A significant negative volume-resistance relationship was observed both in normal subjects (P less than 0.005) and hypertensive patients (P less than 0.001). In comparison with the normal curve, the hypertensive curve has two characteristics: 1) the curve was reset on the right-hand side and, 2) the slope was significantly shallower, indicating a reduced ability to decrease the volume per unit rise in resistance. By using the normal curve as a reference system, a quantitative evaluation of the blood volume disturbance was proposed. In hypertensives, the value of the total peripheral resistance could correspond to two different values of the total blood volume: the real value and the theoretical value extrapolated from the normal curve. The difference between the two values was called "relative variation in blood volume" and was used as a mathematical model. In hypertensives, the real blood volume was significantly reduced (P less than 0.001) while a significant "relative increase" in total blood volume was observed (P less than 0.001). This "relative increase" was directly correlated with the diastolic arterial pressure (r=0.064; P less than 0.00001) and was inversely related to the renal blood flow (r=-0.54; P less than 0.0001) and the creatinine clearance. Such correlations were not observed with the real blood volume. In agreement with Guyton's theory, this study highly suggests that sustained hypertension is related to an increase in blood volume relative to the capacity of the circulatory system and that a renal defect is necessary for the blood pressure elevation mechanism.

Adult↗
PubMed1975

Anti-hypertensive adrenergic-blocking agents: effects on sodium balance, the renin-angiotensin system and haemodynamics.

1. The changes in plasma volume, haemodynamic variables, plasma renin activity and plasma aldosterone were studied in forty-one hypertensive patients after administration of adrenergic-blocking agents. Four drugs were used: alpha-methyldopa (fourteen patients), guanethidine (ten patients), clonidine (nine patients) and reserpine (eight patients). Drugs were administered orally during 7 days' hospitalization on a normal sodium diet (110 mmol/day). 2. The four drugs had similar effects: a significant decrease in blood pressure, a significant increase in plasma volume and no change in stroke volume. 3. With alpha-methyldopa and guanethidine, heart rate, plasma renin activity and plasma aldosterone were unchanged. 4. With reserpine and clonidine, heart rate and plasma renin activity were significantly decreased, whereas plasma aldosterone did not change significantly. 5. This study suggests that the decrease in plasma renin activity was related to the lowering of the heart rate rather than to sodium retention and that adrenergic-blocking agents can impair the normal relationship between stroke index and plasma volume, between plasma volume and plasma renin activity, and between plasma renin activity and plasma aldosterone.

Adult↗