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Biomedical subjects

J Guedon

Publications and source records attributed to J Guedon.

At least 19 recordsLinked to original sources
PubMed1996

Repeated measurements of non-invasive ambulatory blood pressure: distinction between reproducibility and the proper effect of placebo.

OBJECTIVE: To determine whether non-invasive ambulatory blood pressure is more reproducible and less affected by the placebo treatment than are clinic blood pressure measurements. METHOD: Thirty-four essential hypertensive outpatients were randomly allocated after a 4-week preselection period in two groups in a cross-over study design. One group received placebo for 4 weeks while the other formed the control group (reproducibility), then the treatments were exchanged for another 4 weeks. Clinic and ambulatory blood pressures were measured at three different times for each patient, namely bnefore the random allocation to groups and at the end of each period, using a mercury sphygmomanometer and 24 h non-invasive ambulatory blood pressure monitoring. RESULTS: Administration of placebo was accompanied by a significant reduction in systolic and diastolic clinic blood pressures (by 3.4+/-13 and 3.6+/-8 mmHg, respectively), but not in 24 h, daytime and night-time blood pressures. Circadian hourly blood pressure and heart rate curves were virtually superimposable. In the 13 placebo responder patients selected on the basis of clinic blood pressure, placebo decreased the clinic blood pressure and also reduced systolic and diastolic ambulatory blood pressures, mainly during the day period (by 5.2+/-6.2 and 4.89+/-7.8 mmHg, respectively). This effect is specific and related to the placebo administration because repetition of the measurements without any treatment showed no significant difference. To characterize at baseline the placebo responder patients, comparison with the non-placebo responders showed lower baseline values of ambulatory systolic blood pressure recorded during 24 h daytime and night-time in the placebo responder group. CONCLUSION: The 24 h ambulatory blood pressure average is not affected by placebo in the present group of patients but that a placebo effect occurs mainly during the daytime in patients who decreased their clinic blood pressure under placebo (placebo responders); the placebo-induced reduction in blood pressure is related to a specific effect of placebo and is independent from any alerting reaction or reproducibility hypothesis. This study clearly indicates the necessity of including placebo and ambulatory blood pressure monitoring in the therapeutic and pharmacological trials of antihypertensive drugs.

Journal Article↗
PubMed1992

[Arterial hypertension and diabetic nephropathy].

A high incidence of renal lesions is observed in patients with insulin-dependent diabetes. In the early stages of the disease glomerular capillary hemodynamics is altered with, in particular, glomerular hyperfiltration related to several factors: enhanced glomerular capillary flow rate, capillary hypertension and increased filtration area. These hemodynamic changes could affect development of the glomerular microangiopathy: the final outcome of this is the glomerulosclerosis associated with a progressively worsening and ineluctable chronic renal insufficiency. Hypertension, frequent in the early stages, is practically constant when the neuropathy stage has been reached; it is well established that hypertension accelerates the development of glomerular lesions and the progression of the renal impairment. Experimental and clinical studies have clearly demonstrated that antihypertensive treatment slows down the degradation of renal function. All antihypertensive drugs appear to be effective, but converting enzyme inhibitors, by their effects on renal hemodynamics, could play a particular role in the prophylactic treatment of diabetic nephropathy. Determination of urinary excretion of albumin (microalbuminuria), the global evidence of the onset of a nephropathy is useful for the follow up of the renal disease, allows follow up of the renal lesion and evaluation of the efficacy of treatment.

Diabetic Nephropathies↗
PubMed1991

[Isolated urethral amyloidosis. Case report and review of the literature].

Localised amyloidosis of the urethra is an extremely rare condition and we report one case of induration of the corpus spongiosum. This one is painful and increasingly obstructive. The first differential diagnosis we think about was an inflammatory process or carcinoma. The diagnosis can only be done after biopsies and microscopic observation. Localized amyloidosis must be recognized and this lesion must be locally treated. Since 40 years, about 25 such cases were described.

Adult↗
PubMed1989

[Renal effects of captopril in hypertension with renal artery stenosis. Comparison between Tc-99m-DTPA scintigraphy and clearance method].

In eleven hypertensive patients with renal artery stenosis, the acute renal effects of captopril were investigated using two methods: 1) the Tc99m-DTPA renography with determination of an index of renal perfusion (IP), an index of glomerular filtration (IF) and the ratio of these indices (F/P); 2) the renal hemodynamics obtained by the clearance method using a continuous infusion of I131-hippuran and I125-iothalamate for calculation of renal blood flow (RBF), glomerular filtration rate (GFR) and filtration fraction (FF). The studies were performed before and after captopril treatment. Patients were classified according to the acute response to captopril as responders (R; n = 6) and non responders (NR; n = 5). Results are as follows: (B: basal, C = captopril). (table; see text) These data confirm that captopril produced a significant decrease in F/P and FF in R whereas these indices did not change in NR; it was found that IF and GFR decreased in R whereas IF increased and GFR did not change in NR; a significant correlation was observed between delta IF and delta GFR in R (r = 0.834, p less than 0.05). These results indicate that 1) data obtained before and after captopril by renography and by clearance methods are in good correlation either in Ror in NR patients; 2) Captopril test including renography or renal hemodynamic measurements is useful for selection of R patients.

Adult↗
PubMed1988

[Converting enzyme inhibitors in the treatment of arterial hypertension].

Angiotensin converting enzyme inhibitors, in comparison with other antihypertensive agents, offer unquestionable advantages in the treatment of hypertension. They do not alter cerebral blood flow. They improve cardiac function by decreasing postload, by preventing left ventricular hypertrophy and by decreasing myocardial excitability which engenders dysrhythmias. They increase compliance of large arteries and correct renal hemodynamic disturbances in hypertensive patients. Finally, they do not cause metabolic disturbances involving serum blood sugar, uric acid or lipids, and they help conserve potassium in patients on diuretics.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1988

Effects of perindopril on renal haemodynamics and natriuresis in essential hypertension.

Renal haemodynamics and natriuresis were studied before and 6 h after oral intake of perindopril (8 mg) in eight hypertensive patients without renal failure. The patients were then treated with perindopril (8 mg per day) and renal haemodynamics were measured on the fifth day, 6 h after the morning intake. Sodium intake was controlled during the study (100 mmol sodium per day). Renal blood flow and the glomerular filtration rate were measured by the clearance method using 131I-hippuran and 125I-iothalamate, respectively. Mean blood pressure decreased from 135 to 110 after 6 h, and was 118 mmHg on the fifth day (P less than 0.001, respectively). Renal vascular resistance decreased significantly after acute drug intake from 0.19 to 0.15 arbitrary units (P less than 0.001) and on the fifth day to 0.16 arbitrary units (P less than 0.001). Renal blood flow rose from 708 to 723 after 6 h, and to 750 ml/min per 1.73 m2 on the fifth day but the change was no significant. There was no alteration in the glomerular filtration rate so that the filtration fraction decreased from 0.27 to 0.26 (after 6 h), and to 0.25 on the fifth day (P less than 0.02). Natriuresis increased after the first intake between the first and tenth hours. On the fifth day, maximum natriuresis was observed between the fourth and sixth hours. Perindopril caused strong renal vasodilation after the first intake and during the following days, with no change in the glomerular filtration rate. There was a significant decrease in the filtration fraction, indicating efferent, as well as afferent, arteriolar vasodilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Pharmacokinetics of cibenzoline in patients with renal impairment.

Pharmacokinetic values of cibenzoline, a new, investigational, antiarrhythmic drug, were determined in 13 patients with varying degree of renal impairment, creatinine clearance range between 5 and 53 mL/min. Cibenzoline plasma levels were measured after direct intravenous injection of one single 1 mg/kg dose. The apparent volume of distribution of the drug (276 1) was similar to that reported in healthy subjects. Total body clearance decreased with creatinine clearance, and there was a close correlation between cibenzoline renal clearance and creatinine clearance (r = 0.956; P less than 0.001). Plasma elimination half-life was prolonged, with values ranging from 7:4 to 23.6 hours. This study showed that cibenzoline total body clearance correlated with the degree of renal impairment, and it is suggested that in patients with chronic renal failure dosage should be adjusted according to creatinine clearance values.

Adult↗
PubMed1985

Comparative study of muzolimine and acebutolol in the treatment of moderate hypertension.

In a controlled double-blind study the effect of muzolimine (20 mg o.d.) and acebutolol (400 mg o.d.) were investigated in outpatients suffering from moderate essential hypertension. After a three week placebo run-in period, 49 patients were recruited and followed by a cooperative group of general practitioners over a period of 3 months. Blood pressure decreased to the same extent in both groups. With regard to clinical and biological tolerance, no differences appeared between the two drugs.

Acebutolol↗
PubMed1984

[Malignant arterial hypertension, symptomatic and prognostic aspects. Retrospective study of 140 cases].

140 cases of malignant hypertension were diagnosed in our clinic from January 1966 to December 1982. On admission the mean blood pressure was 183 +/- 17 mm Hg, and all patients had grade III to IV retinopathy according to the Keith and Wagener classification; 84% of the patients had renal failure (10% of acute origin). 43% of the patients presented with clinical signs of left heart failure. Hypertension was associated with various renal diseases in 48%, was essential in 41%, and renovascular lesions were found in 9% of the cases. Headaches, asthenia and visual disorders were the 3 main symptoms of malignant hypertension, as classically described. Severe cerebral damage (including all the neurological manifestations present on admission) was found in 27% of the patients. Among the 122 patients available to follow-up, half died during the study period. The survival rate, calculated on a 5-year basis, has doubled compared with a similar patient population 17 years ago, increasing from 35% (period 1966 to 1970) to 72% (period 1977-1982). This remarkable achievement in survival rate is due to more intensive research and therapeutic progress (including, more recently, extrarenal epuration) reaching an increasingly large hypertensive population.

Adolescent↗
PubMed1984

Influence of chronic renal failure on captopril pharmacokinetics and clinical and biological effects in hypertensive patients.

The pharmacokinetic parameters of unchanged plasma captopril and the kinetics of the drug effects on plasma converting enzyme activity (PCEA), plasma renin activity (PRA), plasma aldosterone (PA) and mean blood pressure (MBP) were studied over 24 h after oral administration in three groups of hypertensive patients: with normal renal function (group 1, plasma creatinine less than 110 mumol/l, n = 10), with moderate chronic renal failure (group 2, 135 less than plasma creatinine less than 450 mumol/l, n = 10) and with severe chronic renal failure (group 3, plasma creatinine greater than 500 mumol/l, n = 10). Renal impairment had no effect on plasma captopril Cmax, CLtot and relative bioavailability (AUC). In contrast, captopril kel decreased while T1/2 increased progressively from group 1 to group 3. PCEA blockade (T1/2 and AUC) was increased significantly and proportionally to the degree of renal impairment. However, there were no differences between the three groups regarding captopril-induced modifications of PRA and PA. Although the maximal reduction in MBP was identical in the three groups, the overall antihypertensive effect (AUC) of captopril increased significantly and progressively from group 1 to group 3, especially in duration. There was no correlation between basal plasma creatinine values and unchanged captopril relative bioavailability (AUC) and between unchanged captopril relative bioavailability (AUC) and the drug effects (AUC) on PCEA, PRA, PA and MBP. However there was a correlation between basal plasma creatinine values and plasma captopril T1/2, PCEA blockade (AUC) and overall antihypertensive effect (AUC). The apparent discrepancy between the lack of effects of chronic renal failure on plasma unchanged captopril bioavailability and its potentiating effects on PCEA blockade and MBP reduction may be accounted for by the renal impairment-induced accumulation of captopril metabolites.

Adult↗
PubMed1983

Is dopamine a physiological natriuretic hormone in the dog?

Both plasma and urinary dopamine and noradrenaline were measured as free and sulphate conjugates, by a radioenzymatic method, before and during extracellular volume expansion (ECVE) with hypo-, iso- or hyper-tonic fluid (usually sodium chloride solution) in dogs. During ECVE there was a decrease in plasma catecholamine concentration. For all cases except noradrenaline, this is probably due to a dilution phenomenon since when results were expressed as pg/mg of protein, ECVE had no effect. This change in noradrenaline accounted for the increase in the dopamine/noradrenaline ratio. As expected, there was an increase in the urinary excretion of dopamine during ECVE with both iso- and hyper-tonic fluid. This increase was not observed in the group of dogs given hypotonic fluid, although the increase of fractional excretion of sodium was of a similar order of magnitude. The increase in the urinary excretion of dopamine was apparently not affected by an increase in plasma sodium concentration and/or osmolality. The demonstrated dissociation between sodium and dopamine in urine does not support a physiological role for dopamine in renal handling of sodium during ECVE, and raises the question of its specificity.

Animals↗
PubMed1983

Pre- and posttransplant glomerulonephritis in a case of sarcoidosis.

A 39-year-old woman with documented sarcoidosis and membranous glomerulonephritis (GN) with renal failure received a kidney from her identical twin. A few months after transplantation a proliferative GN appeared with hematuria, proteinuria and progressive renal failure over 2 years. Indeed the occurrence of GN in patients with sarcoidosis raises the question of whether the relationship between these two conditions is causal or fortuitous. This report suggests that GN is secondary to sarcoidosis.

Adult↗
PubMed1983

[Natriuretic effect of haloperidol in dogs].

A 0.5 microM/kg/min infusion of haloperidol in the renal artery of 20 sodium-loaded dogs undergoing water diuresis is showed to induce the following net effects: a statistically significant reduction of both clearance of PAH (-18.1 +/- 6.6 ml/min), and glomerular filtration rate (-4.3 +/- 1.5 ml/min), an increase of both fractional excretion of sodium (+ 6.8 +/- 1.1%) and potassium (+ 55.1 +/- 5.5%), a decrease of fractional excretion of phosphate (-5.3 +/- 1.5%), and a lack of change of free water clearance (infused minus controlateral kidney difference).

Aminophylline↗