Search PubMed⌕ Search

Biomedical subjects

G Jondeau

Publications and source records attributed to G Jondeau.

At least 73 records · Page 4Linked to original sources
PubMed1992

Impaired endothelium-mediated vasodilation in the peripheral vasculature of patients with congestive heart failure.

Impaired endothelial-dependent vasodilation has been demonstrated in two animal models of congestive heart failure and in the coronary circulation of patients with idiopathic dilated cardiomyopathy. To determine whether this impairment contributes to the abnormal peripheral vasomotor tone in patients with congestive heart failure, the local vascular response to intraarterial infusions of graded concentrations (10(-8) M to 10(-5) M) of acetylcholine (an endothelial-dependent vasodilator) and nitroglycerin (a direct-acting vasodilator) was studied in the superficial femoral artery of 19 patients with congestive heart failure (New York Heart Association classes I to IV) and 6 age-matched normal control subjects. The local vascular response was determined from the arterial blood flow velocity pattern obtained by transcutaneous Doppler ultrasonography. Acetylcholine, 10(-5) M, induced a pattern characteristic of vasodilation in all six normal subjects; mean blood flow velocity for the group significantly increased from 11.9 +/- 2.7 to 44.8 +/- 20.9 cm/s (p less than 0.05). In contrast, the same dose of acetylcholine induced a blood flow velocity pattern characteristic of vasodilation in only 4 of the 19 patients with congestive heart failure. Group mean blood flow velocity did not change significantly. Nitroglycerin, 10(-7) M, induced vasodilation in all 6 normal subjects but in only 1 of 19 patients. Nitroglycerin, 10(-5) M, was administered to 10 patients; all 10 demonstrated a pattern characteristic of vasodilation. Thus, acetylcholine-mediated endothelial-dependent vasodilation appears to be impaired in the peripheral vasculature of patients with congestive heart failure. Both endothelial dysfunction and abnormal vascular smooth muscle responsiveness may contribute to abnormal peripheral vasomotor tone.

Acetylcholine↗
PubMed1992

Percutaneous recanalization of a renal artery in aortic dissection.

Chronic renal failure acutely worsened in a patient with a type B aortic dissection. Aortography revealed an occlusion of the left renal artery without renal intimal tear. Percutaneous recanalization, performed with a self-expandable stent, resulted in improvement in the renal function. This technique offers a new therapeutic choice in patients with visceral complications of aortic dissection.

Aortic Dissection↗
PubMed1992

Control of arteriolar resistance in heart failure. Partial attenuation of specific phosphodiesterase inhibitor-mediated vasodilation by digitalis glycosides.

BACKGROUND: The vasodilatory response to local specific type III phosphodiesterase inhibition with amrinone was evaluated before and immediately after local administration of digoxin in 14 patients with severe congestive heart failure (CHF). METHODS AND RESULTS: A 3F polyethylene catheter was inserted into the common femoral artery for drug administration and pressure monitoring. Mean blood flow velocity (MBFV) was continuously determined in the superficial femoral artery by transcutaneous Doppler ultrasonography. After intra-arterial administration of 10 mg amrinone, group MBFV increased from 7.7 +/- 1.4 to 16.0 +/- 2.1 cm/sec (p less than 0.05, n = 10). Local administration of 20 micrograms digoxin, which was infused over 20 minutes, did not alter group MBFV (i.e., 8.2 +/- 1.6 versus 7.6 +/- 1.5 cm/sec; p = NS, n = 10). The second administration of 10 mg amrinone, which immediately followed completion of local digoxin infusion, increased group MBFV but to a lesser extent than that produced by the first amrinone administration (i.e., 11.9 +/- 1.9 versus 16.0 +/- 2.1 cm/sec; p less than 0.05, n = 10). When placebo was administered instead of digoxin, group MBFV was similar after the first and second administrations of amrinone (i.e., 15.3 +/- 3.3 versus 15.6 +/- 3.8 cm/sec; p = NS, n = 4). CONCLUSIONS: Although local administration of digoxin did not significantly alter baseline vascular tone in patients with CHF, it substantially decreased the direct vasodilatory effect induced by specific type III phosphodiesterase with amrinone.

Aged↗
PubMed1992

Active skeletal muscle mass and cardiopulmonary reserve. Failure to attain peak aerobic capacity during maximal bicycle exercise in patients with severe congestive heart failure.

BACKGROUND: In addition to depressed cardiac reserve, peripheral factors may contribute to limit maximal exercise capacity in patients with congestive heart failure (CHF). To investigate the role of reduced active skeletal muscle mass, peak oxygen uptake (VO2, milligrams per kilogram per minute) was determined during maximal symptom-limited exercise involving the lower limbs (LL) alone and the lower limbs and upper limbs (LL+UL) combined in patients with CHF and in normal subjects of similar age and sex. METHODS AND RESULTS: LL bicycle exercise was performed upright with a ramp protocol and continuous expired gas analysis. When respiratory exchange ratio (RER) reached 1.0, UL exercise was initiated at constant load with the use of a cranking device positioned at shoulder level. LL exercise alone and combined LL+UL exercise were performed on separate days in randomized order by 24 patients with CHF and seven normal subjects. In patients with CHF, peak VO2 was greater during combined LL+UL exercise than during LL exercise alone, i.e., 15.8 +/- 0.8 versus 14.2 +/- 0.9 ml.kg-1.min-1 (p < 0.001), whereas in normal subjects, maximal VO2 was similar during the two tests, i.e., 26.7 versus 26.2 ml.kg-1.min-1 (NS). The increase in peak VO2 during combined LL+UL exercise relative to LL exercise alone was almost exclusively observed in patients with peak VO2 < 15 ml.kg-1.min-1 (mean increase, 21.7 +/- 4.1%). Peak VO2 during combined LL and UL exercise did not increase relative to LL exercise alone in patients with peak VO2 > 15 ml.kg-1.min-1 and in normal subjects of similar age and sex, i.e., 0.1 +/- 4.0% and 2.0 +/- 2.3% respectively. CONCLUSIONS: In contrast to normal subjects and patients with moderate CHF, patients with severe CHF do not exhaust their cardiopulmonary reserve during symptom-limited maximal LL exercise on a bicycle.

Exercise Test↗
PubMed1992

Critical analysis of methods for assessing regional blood flow and their reliability in clinical medicine.

The advantages and inadequacies of the currently available techniques to measure regional blood flow in the lower limbs are being reviewed. Thermodilution technique and local 133xenon washout technique have the advantage of allowing determination of blood flow during exercise, while venous occlusion plethysmography and pulsed-Doppler duplex ultrasonography only allow determination of blood flow at rest. Overall, measurements of lower limb blood flow are not highly reproducible by any technique, and the variability in measurements of regional blood flow should lead to careful interpretation of derived parameters such as vascular conductance and resistance. Determination of vascular input impedance by Fourier analysis of pressure data, recorded with high fidelity catheter, and flow velocity measurements obtained transcutaneously by Doppler ultrasonography, may offer a more accurate quantitative analysis of the characteristics of the lower limb vascular system.

Catheterization, Peripheral↗
PubMed1992

[Double-blind clinical and echocardiographic study of oral enoximone versus placebo in severe cardiac insufficiency].

The effect of enoximone was assessed by a randomised double blind trial versus placebo. The clinical status of the patients was evaluated by the NYHA classification and quality of life score. Inotropic state was estimated from the maximum acceleration of aortic and pulmonary blood flow recorded by Doppler echocardiography. Thirty patients with severe cardiac failure, aged 66.4 +/- 14 years, symptomatic despite maximal therapy associating diuretics, digitalis, nitrate derivatives and angiotensin converting enzyme inhibitors, were included. Fifteen patients were given enoximone 100 mg three times a day orally (Group E) and the other 15 were given a placebo (Group P). The NYHA class and quality of life scores were assessed at D0, D4 and D31. Doppler echocardiography and Holter recordings were performed on D0 and D31. The two groups were comparable at D0. Ten patients abandoned the trial, 3 from Group E (including 1 death) and 7 from Group P (including 3 deaths). At D4, 13 patients from Group E and 8 from Group P were clinically improved (p < 0.05). At D31, the clinical state was stable or improved in 10 of the 12 patients in Group E and 6 of the 8 patients in Group P (NS). No secondary effects were severe enough to warrant the withdrawal of treatment: the frequency of ventricular extrasystoles was comparable in the two groups at D0 and D31. At D31 the maximal aortic acceleration had increased by 20% compared with D0 (p < 0.05) and the maximal pulmonary acceleration by 31% (p < 0.05) in Group E. The same parameters showed no significant change in Group P (-6% and +5% respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1992

[Doppler echocardiographic evaluation of vasodilator treatments in patients with cardiac insufficiency. Contribution to the combination of isosorbide dinitrate and captopril].

Hemodynamic evaluation of a vasodilator drug is a difficult exercise in which Doppler echocardiography can be a useful tool. We studied the hemodynamic effect of isosorbide dinitrate (ISDN) by Doppler echocardiography in 7 patients with severe cardiac failure despite prolonged therapy with usually effective doses of captopril. The patients were evaluated before (H0) and 24 hours after treatment by ISDN (120 mg/24 hr) (H24) and 10 minutes after sublingual 0.75 mg of trinitrin (H24 + T). M mode echocardiography did not show any significant changes in chamber dimension as reported after vasodilator therapy in patients without cardiac dilation: in patients with severe left ventricular dilatation a reduction in LV filling pressures causes little if any changes in fractional shortening and ventricular dimensions. Two-dimensional echocardiography showed a reduction in end systolic volume and an increase in ejection fraction, emphasizing the superiority of this technique in cases of abnormal left ventricular function and the sensitivity of indices of systolic function to changes in afterload in these patients. Cardiac output measured by Doppler increased during the study. The maximal acceleration did not change significantly and pulmonary artery pressures were stable after administration of nitrates. ISDN caused a marked change in diastolic mitral flow patterns for which there are several explanations: an effect of ISDN on relaxation or LV compliance or on the conditions of LV filling or on both factors together. The presence of mitral regurgitation and/or atrial arrhythmia prevents the use of Doppler indices for analysis of diastolic LV function.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

[Correlations between plasma concentrations of atrial natriuretic factor and right ventricular function in patients with severe cardiac failure].

The atrial natriuretic factor (ANF) is secreted by the atria in mild and moderate cardiac failure but, during the evolution of the cardiac failure, the ventricles are also recruited and secrete ANF. In order to investigate the relation between plasma ANF and Doppler echocardiographic parameters of severe cardiac failure, the concentrations were measured simultaneously in 20 patients with NYHA Class III and IV cardiac failure (10 due to ischaemic and 10 due to primary dilated cardiomyopathy) despite optimal medical treatment including an angiotensin converting enzyme inhibitor. Overall, there was a weak negative correlation between the plasma ANF concentrations and the decrease in right ventricular surface area (r = -0.58, p less than 0.005, n = 20 patients). This relation was highly significant in ischaemic cardiomyopathy (r = -0.81, p less than 0.002, n = 10 patients) and not significant in primary dilated cardiomyopathy (r = -0.29, NS, n = 10 patients). No relationship was observed between plasma ANF and other echocardiographic parameters (atrial surface area, right and left ventricular dimensions, left ventricular ejection fraction and mass) or with Doppler aortic indices (acceleration, maximum and mean velocities, aortic velocity-time integrals). However, plasma ANF was related to the velocity of mitral regurgitant jets (r = -0.70, p less than 0.01) which is dependent on left ventricular pump function. These results show that plasma ANF concentrations are only related to right ventricular systolic function and the velocity of mitral regurgitation in patients with severe cardiac failure.

Adult↗
PubMed1991

Reciprocal strains in the normal and ischemic myocardium and their relation to the size of the ischemic region.

Previous studies have reported "bulging" of the ischemic zone and reciprocal shortening of the normal zone during the isovolumetric contraction period. This study examines the interaction and relation of these reciprocal strains during the isovolumetric contraction period. Normal zone and ischemic zone segment length data were acquired at 1 ms intervals during acute ischemia in 10 open chest dogs. The relation of ischemic zone and normal zone segment length was inversely linear in the isovolumetric contraction period during steady state ischemia and during preload reduction (mean correlation coefficient 0.92). The slope derived from the regression analysis was the same as that determined from the first and last data points of the isovolumetric contraction period (correlation coefficient between the regression versus two-point slope 0.96). This slope was used to calculate the size of the ischemic area based on the hypothesis that the isovolumetric normal zone shortening quantitatively accounted for the ischemic zone bulging during the isovolumetric contraction period, with the percent risk region serving as a weighing factor. The calculated risk region correlated with the anatomic risk region (r = 0.83, p less than 0.01; n = 9) and was independent of preload. During the isovolumetric contraction period, left ventricular short-axis diameter shortened approximately 0.2%; 80% of the ischemic zone lengthening occurred during this period.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Electrophysiological effects of intravenous rilmenidine in man.

Ten patients (44 y), 6 with the Wolff-Parkinson-White syndrome, and none with hypertensive disease, underwent electrophysiological studies before and after intravenous infusion of a single dose of 1 mg rilmenidine administered over 15 min. The regimen produced a mean plasma rilmenidine concentration of 3.16 ng.ml-1 at the end of the infusion. There was no significant change in sinus cycle length, PR interval, QRS, QT duration or in PA, AH and HV intervals. Estimated sinoatrial conduction time and corrected sinus node recovery time did not significantly change. In one patient, however, an abnormal pause was noted after termination of rapid atrial pacing. The right atrial effective refractory period decreased from 209 to 194 ms. There was no significant change in the anterograde and retrograde block cycle length or in the refractoriness of the nodal, ventricular and accessory pathways. The cycle length of induced reciprocating tachycardia decreased slightly from 374 to 351 ms. No patient exhibited an abnormal response to the carotid sinus massage. The findings indicate that intravenous administration of 1 mg rilmenidine exerts modest effects on the electrophysiological parameters of the human heart.

Administration, Oral↗
PubMed1991

Stiffness of the common carotid artery in treated hypertensive patients.

Antihypertensive treatment, by lowering blood pressure and correcting functional and/or structural abnormalities of the arterial wall, may prevent the arterial damage due to the accelerated ageing process. The objective of the present study was to determine, using a cross-sectional approach, whether arterial distensibility of patients whose blood pressure had been normalized for several months by antihypertensive treatment, was significantly higher than that of untreated hypertensive patients. The properties of the vessel wall of the common carotid artery (CCA) were studied non-invasively, using an original pulsed ultrasound echo-tracking system based on Doppler shift, during a study comparing 46 normotensive subjects and 81 age-matched hypertensive patients. The latter group included 25 patients well controlled by antihypertensive treatment for at least 3 months and 56 untreated hypertensives. The three groups did not differ with respect to age, total and high-density lipoprotein cholesterol, blood glucose and smoking. In each group, there were significant relationships between age and CCA dimensional and functional data, including end-diastolic diameter, absolute and relative stroke changes in diameter and Peterson modulus, indicating a widening of the CCA with advancing age and a decrease in its buffering function. When compared with untreated hypertensives, well controlled hypertensives had significantly lower blood pressure and Peterson elastic modulus according to age. However, although blood pressure of well controlled hypertensives was not significantly different from that of normotensive subjects, their arterial distensibility remained altered compared with that of normotensive subjects (significant increase in Peterson elastic modulus). These results suggest that long-term antihypertensive treatment may not fully reverse arterial lesions due to the hypertensive disease.

Adult↗
PubMed1991

[Visco-elastic properties of common carotid artery in treated hypertension].

It is now possible to measure clinically by a non-invasive method systolo-diastolic variations of the internal diameter of large arteries over 4 to 10 cardiac cycles with an original vascular echo-tracking device using Doppler shift. By the means of a transversal study of healthy subjects and patients followed up in the hypertension clinique, the authors set out to determine whether long-term non-specific antihypertensive treatment could, by correcting the blood pressure, also normalise the vascular changes encountered in hypertension. This study compared 46 normotensive subjects (Group I), 25 essential hypertensive patients with normal blood pressure recordings after at least 3 months' treatment (Group II) and 56 untreated essential hypertensive patients of the same average age (range 24 to 78 years). The common carotid artery was chosen for study of its geometry (internal diastolic diameter: Dd) and function (relative systolic expansion Ds-Dd/Dd; Perterson's elastic modulus; cross sectional compliance). The arterial diameter increased significantly with age in all three patients groups. In patients under 60 years of age, the diameter, corrected for age and sex, was significantly greater in Group II than in Group I, and similar in Groups II and III. This suggests that in spite of correcting blood pressure by long-term therapy (4.1 +/- 4.1 years), the internal diameter of a large artery such as the common carotid artery remains increased, which is in favour of the persistence of structural arterial changes rather than a prolonged vasodilator effect of the antihypertensive agents used.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Linkage analysis of five fibrillar collagen loci in a large French Marfan syndrome family.

Marfan syndrome consists of a group of dominantly inherited disorders of connective tissue with wide clinical variability. Using the candidate gene approach, we have attempted to map the gene defect in a large French Marfan syndrome family with no ocular manifestations. We performed linkage studies with polymorphic probes for five structural procollagen genes. The data obtained exclude linkage of Marfan syndrome to the two major fibrillar collagen (COL1A1, COL1A2, and COL2A1) genes. These results confirm previously published data obtained from smaller pedigrees. A small positive lod score (Z = 0.99, theta = 0.00) was obtained for the COL3A1-COL5A2 gene cluster located on chromosome 2.

Chromosome Mapping↗
PubMed1989

Tall T waves during metabolic acidosis without hyperkalemia: a prospective study.

The specific ECG characteristics of metabolic acidosis have not been satisfactorily defined in man. We addressed this question by prospectively studying 14 consecutive patients admitted with metabolic acidosis and without hyperkalemia. Arterial blood gas analysis and serum potassium determinations were performed during acidosis and after its correction. ECGs were recorded at the same times. Mean pHa increased from 7.11 +/- 0.05 to 7.40 +/- 0.01 (p less than .001) in response to an increase in total CO2 content from 6.8 +/- 1.4 to 21.2 +/- 0.7 mmol/L (p less than .001). Serum potassium concentration decreased only slightly after correction of the acidosis from 4.2 +/- 0.1 to 3.9 +/- 0.14 mmol/L (p less than .05). T waves were taller during acidosis than after correction (0.68 +/- 0.1 vs. 0.28 +/- 0.04 mV, p less than .001 and 0.64 +/- 0.08 vs. 0.38 +/- 0.04, p less than .005, in precordial leads V2 and V3, respectively). Moreover, the amplitude of T waves in V2 was correlated positively with the arterial concentration of H+ (r = .786, p less than .001) and negatively with the arterial total CO2 content (r = -.71, p less than .005). In addition to their augmented amplitude, T waves were peaked and symmetrical with a narrow base ("tent-shaped"). Thus, metabolic acidosis may be accompanied by an increase in the amplitude of T waves, even in the absence of hyperkalemia.

Acid-Base Equilibrium↗
PubMed1989

Tamm-Horsfall protein accumulation in glomeruli during acetazolamide-induced acute renal failure.

A patient with ocular hypertension was treated with acetazolamide. Acute renal failure developed rapidly and renal biopsy showed mild tubular lesions and crystal formation in a tubular lumen. By immunofluorescence studies with a monoclonal antibody, Tamm-Horsfall protein, normally absent from the proximal segments of the nephron, was detected in most glomeruli. This strongly suggests that tubular obstruction plays a major part in some cases of acetazolamide-induced acute renal failure.

Acetazolamide↗
PubMed1986

Effects of an intravenous infusion of noradrenaline on the plasma concentration of free and sulfoconjugated catecholamines in anesthetized dogs.

Exogenous noradrenaline (NA) was infused intravenously at increasing rate from zero (control) to 10, 25, 50, 100, 200 and 600 ng/kg/min during 20 min in anesthetized and ventilated dogs; the mean (+/- SEM) plasma concentration of free NA was increased from 130 +/- 23 pg/ml (basal) to 7,826 +/- 787 pg/ml. This had no measurable effect on the plasma concentration of dopamine and adrenaline in either free or sulfoconjugated form; a lack of change was also observed in dogs given a 600-ng/kg/min infusion during more than 2 h. The increase of free NA concentration was highly correlated both with the infusion rate, and with the blood pressure. Contrary to expectations, the plasma concentration of NA sulfate decreased in all 5 dogs when plasma NA concentration was progressively increased from basal to about 1,600 pg/ml; beyond this apparently crucial level (i.e. from about 1,600 to 7,826 pg/ml), the response of NA sulfate concentration was erratic, as it was in dogs given a 600-ng/kg/min infusion during more than 2 h. If the response of canine blood pressure is examined in the light of the level of free NA concentration, two mechanisms can be suspected: (1) when the NA level increased from basal to about 1,600 pg/ml, a direct action upon peripheral resistances was likely to be the predominant hypertensive mechanism; (2) beyond about 1,600 pg/ml, a combined effect of NA on both peripheral resistances and cardiac hemodynamics could have a role in the hypertensive process. Thus, a concentration of NA of about 1,600 pg/ml appears to be a landmark for both CA metabolism and circulatory homeostasis. Further studies will have to be carried out to investigate whether this represents the upper physiological concentration in the anesthetized dog.

Anesthesia↗