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Biomedical subjects

F Blanchet

Publications and source records attributed to F Blanchet.

At least 37 records · Page 2Linked to original sources
PubMed1990

Beta blockers induce different intrarenal effects in humans: demonstration by selective infusion of tertatolol and propranolol.

The effects of tertatolol and propranolol on renal circulation were studied in patients with normal renal function to test the hypothesis that various beta blockers may have different vasomotor effects within the renal vascular bed. Left renal blood flow was measured by the continuous thermodilution method before (t0), and 5 (t1), 10 (t2), 20 (t3), and 30 (t4) minutes after a selective infusion of tertatolol (0.25 mg, N = 4) or propranolol (2.5 mg, N = 4) into the left renal artery. Heart rate, cardiac output, aortic and right atrial pressures, and systemic vascular resistances did not significantly vary after either drug throughout the study. Plasma renin activity and plasma aldosterone in arterial and renal venous blood started to decrease at t1 after each drug. After propranolol, renal blood flow, renal vascular resistance and the renal arteriovenous oxygen difference were unchanged. Conversely, after tertatolol at t3, renal blood flow was increased (from 426 +/- 18 mL/min/1.73 m2 to 509 +/- 56 mL/min/1.73 m2, P = .03), renal vascular resistance and renal arteriovenous oxygen difference were decreased (P less than .001), and the renal blood flow/cardiac output ratio was increased (P = .03). The filtration fraction did not vary after either drug, as attested by the unchanged polyfructosan extraction coefficient. This clinical study shows that selective infusion of a single low dose of tertatolol into the renal artery results in a delayed intrarenal vasodilator effect, while at the dose tested propranolol does not modify renal hemodynamics.

Adrenergic beta-Antagonists↗
PubMed1990

Fiberoptic bronchoscopy in ventilated patients. Evaluation of cardiopulmonary risk under midazolam sedation.

One hundred seven acutely ill ventilated patients were prospectively studied to ascertain the severity and frequency of alterations in gas exchange and hemodynamic parameters during brief bronchoscopy. Sedation was performed using midazolam (0.1 mg/kg IV) without topical anesthesia. An average decline in PaO2 of 26 percent was observed at the end of the procedure, compared to the baseline value, and this was associated with a mild increase in PaCO2 in spite of the use of a special adapter. Alterations in mean systolic blood pressure appeared to be modest, consisting of a 10 percent decrease from the control level, related to sedation, and a 10 percent rise from baseline during the procedure, associated with a concomitant mild tachycardia. At that time, central hemodynamic measurements performed in a subset of 31 patients showed a significant increase in cardiac output associated with higher pulmonary wedge pressure. Fourteen patients developed hypoxemia of less than 60 mm Hg on FIO2 adjusted to 0.8. Of the ten risk factors univariately associated with hypoxemia, only the presence of ARDS (p less than 0.001) and "fighting" the ventilator during the procedure (p less than 0.05) remained significant after stepwise logistic regression. Attempts to prevent hypoxemia in critically ill patients should focus on inducing complete sedation, with careful attention to hemodynamic status, or providing maximal levels of oxygen to the ventilator (or both).

Adult↗
PubMed1989

Renal functional reserve.

Renal functional reserve represents the capacity of the kidney to increase its level of operation in response to certain demands. The reserve of glomerular filtration rate and of renal blood flow is discussed from the following points of view: evaluation, measurement, mechanisms involved and significance. Data from the literature are discussed which show (i) that the mechanism of the hyperfiltration seen in the early stage of diabetic nephropathy may be different from the hyperfiltration induced by infusion of amino acids, (ii) that the remaining kidney in healthy kidney donors maintains its functional reserve, and (iii) that the functional reserve is fairly well maintained as long as the glomerular filtration rate is decreased only moderately. The reserve of tubular functional capacity is discussed from the point of view of concentration and dilution and of acidification and alkalinization.

Blood Flow Velocity↗
PubMed1989

Selective infusion of tertatolol into the renal artery induces a local vasodilator effect in humans. Demonstration by the continuous thermodilution method.

The effects of tertatolol on renal circulation were studied in 8 patients with normal renal function. Left renal blood flow was measured by the continuous thermodilution method before (t0), and 5 (t1), 10 (t2) and 20 (t3) min after a selective infusion of 0.25 mg of tertatolol into the left renal artery. During the study, cardiac output, heart rate, aortic and right atrial pressures, systemic vascular resistances and the systemic arteriovenous oxygen difference were not significantly altered. Plasma renin activity and plasma aldosterone in arterial and renal venous blood started to decrease at t1. At t3, renal blood flow was increased (from 463 +/- 28 mL/min at t0, to 549 +/- 22 mL/min, P less than .001), renal vascular resistance was reduced (from 188 +/- 17 mm Hg/L/min at t0 to 156 +/- 15 mm Hg/L/min, P less than .01) and the arteriovenous oxygen difference was decreased (from 1.6 +/- 0.2 mL/100 mL at t0 to 1.1 +/- 0.1 100 mL, P less than .01). The renal/cardiac flow ratio increased from 10.0 +/- 2.2% to 11.7 +/- 2.1% (P less than .05) and the renal/systemic vascular resistance ratio decreased from 10.5 +/- 2.0 to 8.7 +/- 1.4 (P less than .01). These data show that selective infusion of a low dose of tertatolol into the renal artery results in an increase in renal blood flow which is delayed and occurs without concomitant changes in systemic hemodynamics. This suggests an intrarenal mechanism of action in humans supporting the previously observed renal vasodilation induced by tertatolol in isolated perfused animal kidneys.

Adult↗
PubMed1989

A reliable potentiometric measurement of ionized calcium and pH on the ICA2 Radiometer in clinical practice.

A second generation analyser for potentiometric measurement of ionized calcium and pH (ICA2 Radiometer, Copenhagen) was tested with respect to analytical performance in two different laboratories. Newly-developed aqueous buffered solutions were used at different Ca2+ concentrations as well as biological specimens prepared from human subjects. The overall precision of ICA2 was very good: CV = 0.0-0.4% for within-run and 0.4-1.7% for day-to-day precision with protein-free solutions and CV = 0.3-0.9% for within-run precision on biological specimens. The adjusted value of Ca2+ to pH 7.40 is an analytical advantage for which the calculation is correct but the assumption made for this algorithm may limit its clinical relevance. Measurements were comparable on ICA2 when performed on either whole blood, serum or plasma. Pre-analytical conditions should be observed such as the choice of anticoagulant and anaerobic conditions. Such a reliable and accurate instrument may promote the use of ionized calcium measurement in daily clinical practice.

Calcium↗
PubMed1989

[Prosthetic vocal rehabilitation of Herrmann's type after total laryngectomy. Results apropos of 29 cases].

The authors performed 29 surgical interventions of this type (24 primary and 5 secondary implantations). The treatment protocols, especially, the radio-chemotherapeutic protocols, were not changed and the radiotherapeutic tolerance of these prosthetic implants was particularly outstanding. This method may find wide application as well after single total laryngectomy as after circular total pharyngeal laryngectomy with restoration by gastric transplant. Speech is generally produced as early as the 12th day and we may assert that it is much better than esophageal speech, the whole indications and results being considered. These are being discussed and sustained support by the therapeutic team appears to be necessary.

Humans↗
PubMed1988

Cancer of the larynx/hypopharynx, tobacco and alcohol: IARC international case-control study in Turin and Varese (Italy), Zaragoza and Navarra (Spain), Geneva (Switzerland) and Calvados (France).

A case-control study on larynx and hypopharynx cancer was carried out in 6 populations including the city of Turin and the province of Varese (Italy), the provinces of Navarra and Zaragoza (Spain), the canton of Geneva (Switzerland), and the département of Calvados (France). This report presents an analysis of the risk associated with alcohol and tobacco consumption based on 1,147 male cases and 3,057 male population controls. Special attention was given to the study of the risk at various sites of larynx and hypopharynx. The effect of tobacco is similar for all sites and the risk associated with ever smoking is on the order of 10. The risks from alcohol drinking depend on site. They are similar for epilarynx and hypopharynx (RR = 4.3, for more than 80 g/day) and lower for endolarynx (RR = 2.1, for more than 80 g/day). For all sites the risk decreases after quitting (RR = 0.3 after 10 years); exclusive use of filter cigarettes is protective (RR = 0.5 relative to smokers of plain cigarettes only) as is exclusive use of blond tobacco (RR = 0.5 relative to smokers of black tobacco only). Inhalation increases the risk of endolaryngeal cancer but not that of hypopharynx or epilarynx. The relative risks for joint exposure to alcohol and tobacco are consistent with a multiplicative model.

Adult↗
PubMed1988

Coronary flow and resistance reserve in patients with chronic aortic regurgitation, angina pectoris and normal coronary arteries.

Left ventricular hypertrophy has been found to be associated with a reduction of coronary vascular reserve, which could be responsible for episodes of myocardial ischemia. To evaluate coronary flow and resistance reserve in patients with chronic aortic regurgitation, coronary sinus blood flow and coronary resistance were measured before and after an intravenous dipyridamole infusion (0.14 mg/kg per min X 4 min) in eight control subjects and eight patients with aortic regurgitation, exertional angina pectoris and normal coronary arteriograms. Coronary flow reserve, evaluated by the dipyridamole/basal coronary sinus blood flow ratio, and coronary resistance reserve, evaluated by the basal/dipyridamole coronary resistance ratio, were both significantly reduced in patients with aortic regurgitation (1.67 +/- 0.40 versus 4.03 +/- 0.52 in control subjects, p less than 0.001 and 1.71 +/- 0.50 versus 4.38 +/- 0.88 in control subjects, p less than 0.001, respectively). In patients with aortic regurgitation, basal coronary sinus blood flow was higher than in control subjects (276 +/- 81 versus 105 +/- 24 ml/min, respectively, p less than 0.001) and basal coronary resistance was lower (0.31 +/- 0.13 versus 0.95 +/- 0.17 mm Hg/ml per min, respectively, p less than 0.001), but coronary blood flow and resistance after dipyridamole were not significantly different in the two groups (461 +/- 159 versus 418 +/- 98 ml/min in control subjects, 0.19 +/- 0.11 versus 0.22 +/- 0.04 mm Hg/ml per min in control subjects, respectively). These data demonstrate that coronary reserve is severely reduced in patients with chronic aortic regurgitation and exertional angina.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Tolerance of once-daily dosing of netilmicin and teicoplanin, alone or in combination, in healthy volunteers.

The purposes of this study were to test the pharmacokinetics and renal and otologic tolerances of a once-daily regimen of netilmicin and teicoplanin administered intramuscularly, alone or in combination (4.5 and 6 mg/kg, respectively), for 7 days in 30 healthy male volunteers. Teicoplanin induced only a mild increase in enzymuria. Nephrotoxicity was moderate and reversible with netilmicin; there was increased enzymuria and alteration in diluting ability, without significant changes in urinary beta 2-microglobulin levels, concentrating ability, and glomerular filtration rate. Ototoxicity was not detected in any of the subjects. Our results suggest that (1) teicoplanin and netilmicin given once daily induced only slight, reversible tubular damage, without any sign of ototoxicity; (2) their combination was not more toxic; and (3) clinical studies can be envisaged to evaluate the efficacy and tolerance of once-daily regimens in long-term treatment.

Acetylglucosaminidase↗
PubMed1988

Ca2+ measurement with ion selective electrodes. The French coordinated evaluation of seven analyzers, for a better clinical relevance and acceptance.

The measurement of ionized calcium has evolved in the last decade, and can now be easily performed by clinical laboratories using direct potentiometric analyzers available from a number of manufacturers. An original protocol for a comparison of the analyzers was used through a parallel multicenter evaluation in France. Using newly developed aqueous buffered solutions, this study focused not only on the analytical performance and operational handling of analyzers, but also on possible interferences in biological samples and the clinical relevance of the measurement with respect to the techniques of sample collection. All the instruments exhibited good precision and linearity, and were easy to handle and robust for daily use. However, not all the models gave identical results on the same patient's specimen. The utility of some Ca2+ analyzers has been further enhanced by the ability to "correct" the results to pH 7.40, although care must be taken in the interpretation of these results. While there are a number of clear-cut situations in which Ca2+ measurement is more relevant than total calcium, it seems that chemical activity of Ca2+ in blood may sometimes be considered with great caution under pathological conditions. The role of Ca2+ measurement in routine will be discussed in relation to the potential benefits of the instruments in laboratories.

Autoanalysis↗
PubMed1987

[Interstitial nephropathies induced by meticillin: demonstration of distal tubule functional anomalies].

Renal tubular dysfunction was investigated in two patients with meticillin-induced interstitial nephritis. Some degree of renal failure persisted after the acute episode in both cases. The first patient was investigated 10 weeks after the onset of the nephropathy. Nephrogenic diabetes insipidus and distal tubular acidosis were demonstrated. The second patient was investigated 7 months after the onset of the nephropathy. A major impairment in urinary concentration ability was demonstrated. Neither patient had proximal tubular dysfunction. These data show that meticillin-induced interstitial nephritis may be responsible for distal tubular abnormalities, namely nephrogenic diabetes insipidus and distal tubular acidosis, which may persist long after the onset of the nephropathy.

Adult↗
PubMed1986

Effect of diltiazem on coronary reactive hyperemia in patients with flow-limiting coronary artery stenosis.

The acute effects of diltiazem on coronary reactive hyperemia were studied in 12 patients with flow-limiting coronary stenosis. Reactive hyperemia was elicited by injection of 8 ml contrast medium into the left coronary artery, while coronary sinus blood flow and left ventricular and aortic pressures were continuously recorded. Relative magnitude of hyperemia was estimated by the ratio of coronary flow at peak hyperemia to baseline flow (hyperemic ratio). Coronary resistance was calculated as the ratio between mean aortic pressure minus left ventricular mean diastolic pressure and coronary sinus blood flow. The 12 patients studied had flow-limiting coronary stenosis since their hyperemic ratio was significantly restrained when compared to that of seven control subjects (1.45 +/- 0.17 vs 2.02 +/- 0.24, respectively; p less than 0.001). The intravenous infusion of diltiazem (0.30 mg X kg-1) reduced heart rate, mean aortic pressure, and myocardial oxygen consumption (all p less than 0.001). After diltiazem the hyperemic ratio was blunted when compared to the basal state (1.36 +/- 0.15 vs 1.45 +/- 0.17, respectively; p less than 0.05), and hyperemia volume was reduced (-33%; p less than 0.001). The decrease in coronary resistance at peak hyperemia was also reduced from -30 +/- 8% to -25 +/- 8% (p less than 0.05). We conclude that diltiazem blunts coronary reactive hyperemia in patients with demonstrated flow-limiting coronary stenosis. This reduction of coronary flow response to a hyperemic stimulus could favorably influence blood flow distribution in patients with significant coronary stenosis.

Adult↗
PubMed1986

Effects of midazolam on the coronary circulation in patients with coronary artery disease.

The effects of midazolam on coronary sinus blood flow (CSBF), myocardial oxygen consumption (MVO2), and myocardial lactate balance were investigated in eight patients with stable coronary artery disease undergoing cardiac catheterization. Coronary sinus blood flow was measured by continuous thermodilution. Arterial and coronary sinus blood were analyzed for oxygen and lactate content. The determinants of left ventricular (LV) performance were obtained from the cardiac output measured by thermodilution and from left heart catheterization data. All data were obtained before, and 5 and 15 min after midazolam, 0.2 mg X kg-1 iv. Sleep was induced in all patients after administration of midazolam and persisted throughout the entire study period. Mean aortic and LV end-diastolic pressure were decreased from control values (-15 and -44%, respectively), as well as cardiac index and stroke index (-10 and -15%, respectively). Heart rate increased moderately (+8%), while no change in systemic vascular resistance and maximum velocity of shortening (Vmax) were observed. Midazolam administration was followed by a decrease of CSBF (-24%) and of MVO2 (-26%). Coronary vascular resistance did not change, but coronary sinus oxygen tension increased slightly, suggesting a mild alteration in normal autoregulation. However, no evidence of myocardial ischemia occurred, as judged by the absence of changes in the: 1) ECG, 2) myocardial lactate extraction, and 3) relaxation time constant. These results suggest that midazolam may be used safely in patients with coronary artery disease.

Anesthesia↗
PubMed1985

Multifactorial determinants of reduced coronary flow reserve after dipyridamole in dilated cardiomyopathy.

Coronary sinus blood flow (ml/100 g left ventricular [LV] mass/min) and coronary resistance (mean aortic minus LV mean diastolic pressures/coronary sinus blood flow, mm Hg/[ml/100 g/min]) were studied in 7 control patients and in 11 patients with severe dilated cardiomyopathy (DC) and normal coronary arteriograms. Basal coronary sinus blood flow was not different in the 2 groups. After intravenous administration of dipyridamole (0.14 mg/kg/min X 4 min), coronary sinus blood flow and dipyridamole/basal coronary sinus blood flow ratio were significantly (p less than 0.001) lower in the DC group than in the normal group (coronary sinus blood flow 188 +/- 48 vs 408 +/- 58, respectively; blood flow ratio 1.78 +/- 0.35 vs 4.01 +/- 0.56, respectively), and the coronary resistance was higher in the DC group than in the control group (0.39 +/- 0.15 vs 0.22 +/- 0.03, respectively, p less than 0.01). After administration of dipyridamole in patients with DC, no correlation could be found between coronary sinus blood flow and LV mean diastolic, mean aortic or coronary driving pressures, i.e., mean aortic minus LV mean diastolic pressures. Thus, in DC patients, neither an elevated LV diastolic pressure nor a low coronary perfusion pressure can totally account for the restriction of the coronary flow reserve after dipyridamole.

Adult↗
PubMed1985

Decreased coronary reserve in primary scleroderma myocardial disease.

We assessed coronary reserve, by measuring the increase in coronary sinus blood flow (CSBF) after intravenous administration of dipyridamole (0.14 mg/kg/minute for 4 minutes), in 7 patients with primary scleroderma myocardial disease (PSMD) and in 7 control subjects. Coronary reserve was greatly impaired in PSMD: before administration of dipyridamole, CSBF was similar in patients with PSMD (89 +/- 32 ml/minute/100 gm, mean +/- SD) and in controls (100 +/- 15 ml/minute/100 gm); after dipyridamole infusion, CSBF was significantly lower in patients with PSMD (191 +/- 45 ml/minute/100 gm) than in controls (399 +/- 58 ml/minute/100 gm) (P less than 0.01). Six of the 7 patients with PSMD had angiographically normal epicardial coronary arteries and normal left ventricular function. Decreased coronary reserve may be an important contributor to the pathogenesis of primary scleroderma myocardial disease.

Adult↗