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Biomedical subjects

F Comte

Publications and source records attributed to F Comte.

At least 19 recordsLinked to original sources
PubMed2006

Accuracy and precision of perfusion lung scintigraphy versus 133Xe-radiospirometry for preoperative pulmonary functional assessment of patients with lung cancer.

PURPOSE: This study sought to determine whether (133)Xe-radiospirometry (XRS) successfully selects patients able to undergo lung resection without postoperative respiratory complications and whether perfusion lung scintigraphy (PLS) is likely to provide a similar selection of patients for certain tumour stages. METHODS: Two hundred and eighty-four patients with resectable lung cancer underwent preoperative assessment of postoperative forced expiratory volume in 1 s (FEV(1)) by XRS and PLS. Correlations, Bland and Altman analysis and contingency tables were used to analyse the difference between the two predictive techniques. RESULTS: One hundred and sixty patients underwent lung resection on the basis of XRS preoperative testing only. None of them developed respiratory insufficiency. Despite a close correlation, the limits of agreement between predicted FEV(1) by XRS and PLS exceeded +/-0.3 l/s. For tumour stages T1Nx and T2N0, PLS underestimated postoperative FEV(1) whereas it overestimated this parameter for stage III. CONCLUSION: XRS accurately selects patients able to undergo lung resection without postoperative pulmonary insufficiency. The agreement between XRS and PLS is unacceptable. When only PLS is available, higher thresholds for patients with stage III cancers and lower thresholds for those with stage I cancers should be used to decide on operability.

Adult↗
PubMed2006

Myocardial perfusion imaging and cardiac events in a cohort of asymptomatic patients with diabetes living in southern France.

AIMS: To assess the association between abnormal stress myocardial perfusion imaging (MPI) and cardiac events (CE) in asymptomatic patients with diabetes and with > or = 1 additional risk factor. Predictors of abnormal stress MPI were also evaluated. METHODS: Four hundred and forty-seven consecutive patients who underwent stress MPI were prospectively followed for 2.1 [0.5-4.1] years for the subsequent occurrence of hard CE (myocardial infarction and sudden or coronary death) and soft CE (unstable angina and ischaemic heart failure requiring hospitalization). Re-vascularization procedures performed as a result of the screening protocol were not included in the analysis. RESULTS: Follow-up was successful in 419 of 447 patients (94%), of whom 71 had abnormal MPI at baseline. Medical therapy was intensified in all subjects and especially in those with abnormal MPI. Twenty-three patients with abnormal MPI underwent a re-vascularization procedure. CEs occurred in 14 patients, including six of 71 patients (8.5%) with abnormal MPI and eight of 348 patients (2.3%) with normal MPI (P < 0.005). Only two patients developed a hard CE and 12 a soft CE. In multivariate analysis, abnormal MPI was the strongest predictor for CEs [odds ratio (OR) (95% CI) = 5.6 (1.7-18.5)]. Low-density lipoprotein cholesterol > or = 3.35 mmol/l [OR (95% CI) = 7.3; 1.5-34.7] and age > median [OR (95% CI) = 6.0 (1.2-28.6)] were additional independent predictors for CE. The independent predictors for abnormal MPI were male gender, plasma triglycerides > or = 1.70 mmol/l, creatinine clearance < 60 ml/min and HbA1c > 8%, with male gender the strongest [OR (95% CI) = 4.0 (1.8-8.8)]. CONCLUSIONS: Asymptomatic patients with diabetes in this study had a very low hard cardiac event rate over an intermediate period. This could be explained by the effects of intervention or by the low event rate in the background population. Randomized studies of cardiac heart disease screening are required in asymptomatic subjects with diabetes to determine the effectiveness of this intervention.

Aged↗
PubMed2001

Routine measurements of left and right ventricular output by gated blood pool emission tomography in comparison with thermodilution measurements: a preliminary study.

The aim of this preliminary study was to evaluate the accuracy of left and right ventricular output computed from a semi-automatic processing of tomographic radionuclide ventriculography data (TRVG) in comparison with the conventional thermodilution method. Twenty patients with various heart diseases were prospectively included in the study. Thermodilution and TRVG acquisitions were carried out on the same day for all patients. Analysis of gated blood pool slices was performed using a watershed-based segmentation algorithm. Right and left ventricular output measured by TRVG correlated well with the measurements obtained with thermodilution (r = 0.94 and 0.91 with SEE = 0.38 and 0.46 l/min, respectively, P < 0.001). The limits of agreement for TRVG and thermodilution measurements were -0.78-1.20 l/min for the left ventricle and -0.34-1.16 l/min for the right ventricle. No significant difference was found between the results of TRVG and thermodilution with respect to left ventricular output (P = 0.09). A small but significant difference was found between right ventricular output measured by TRVG and both left ventricular output measured by TRVG (mean difference = 0.17 l/min, P = 0.04) and thermodilution-derived cardiac output (mean difference = 0.41 l/min, P = 0.0001). It is concluded that the watershed-based semi-automatic segmentation of TRVG slices provides non-invasive measurements of right and left ventricular output and stroke volumes at equilibrium, in routine clinical settings. Further studies are necessary to check whether the accuracy of these measurements is good enough to permit correct assessment of intracardiac shunts.

Adult↗
PubMed1984

[Hyperammonemia and decrease of growth and nocturnal locomotion in rats with portal stricture and uremia].

In order to make clearer the pathogenesis of hepatic coma, the clinical tolerance of progressive levels of chronic hyperammonemia were studied in the rat. Increases of blood ammonia in the range of 200 to 600 micrograms/dl were produced within 4 weeks by stricture of the portal vein associated with progressive rises in blood urea resulting from reduction of the renal mass and/or addition of urea to the food. The portal stricture produces a collateral circulation allowing a hepatic bypass of portal blood and the ammonia level of this blood is proportional to the amount of circulating and alimentary urea hydrolyzed in the digestive tract. Only the highest hyperammonemias were associated with decreased nocturnal locomotion of the rats and decrease in the growth rate. The latter was correlated with the ammonia levels. No animal presented signs of coma. These results suggest a good cerebral tolerance by the rat of important chronic hyperammonemias which however seem to have an anorexic effect.

Ammonia↗
PubMed1983

[Breakfast tolerance test: application to the detection of gestational diabetes].

There is general agreement that diagnosis of diabetes mellitus in pregnancy is requisite but the means of achieving it are still under discussion. The plasma glucose, insulin and C peptide responses to an oral glucose tolerance test were compared with the intravenous glucose tolerance test and a standardized breakfast tolerance test in 26 pregnant women, in order to define a simple diagnostic criterion for gestational glucose intolerance. The results of the oral glucose tolerance test distinguished between a group of 19 normal women and a group of 7 diabetic women with abnormal glucose tolerance tests. The breakfast tolerance test used (84 g carbohydrates, 22,6 g protein, 9,4 g fat, 690 calories) was followed by blood glucose modifications very similar to those observed with the oral glucose tolerance test, but the insulin response was significantly greater. The consistency between the breakfast tolerance and intravenous glucose tolerance tests was confirmed by the existence of correlations between the glucose area of the breakfast tolerance test and the coefficient K in the two groups studied. Our results suggest that the breakfast tolerance test could be as sensitive as the oral glucose tolerance test for detecting glucose intolerance; the most discriminative glycemic value appeared to be that at the 180 th minute, usually under 1 g/l in the normal pregnant women. This test could be proposed as an easy and economic method for diagnosing gestational diabetes. These preliminary results require confirmation by a study in a larger population.

Administration, Oral↗
PubMed1982

[Pharmacokinetics of intramuscular mezlocillin in patients with normal and impaired renal function (author's transl)].

Pharmacokinetic values of mezlocillin were determined after a single intramuscular injection of 1 g to 10 subject with normal renal function, 10 patients with stable renal insufficiency and 5 patients with chronic renal failure under long-term haemodialysis. The values obtained in normal subjects were : biological half-life Tb 1/2 0.9 hour; elimination constant Ke 0.790 (h-1); total clearance Ct 449 ml/min/1.73 m2; renal clearance Cr 263 ml/min/1.73 m2. Twelve hours after the injection 72.2 % of the dose administered were recovered in the urine. Theoretical values after repeated injection were calculated from the values obtained in subjects with normal renal function. The loading doses providing steady state serum concentrations were determined for various dosage intervals (2, 3, 4, 6 and 8 hours). In patients with renal insufficiency or treated with haemodialysis, serum levels decreased more slowly. The theoretical Tb 1/2 for zero creatinine clearance was 4.7 hours. Sixty-two percent of the amount of mezlocillin present in the central compartment at the onset of haemodialysis were removed after a 6-hour dialysis session. In all 25 subjects investigated, a significant correlation was found between Ke and Ccr (Ke = 0.1973 + 0.0046 Ccr). This correlation was used to calculate the loading and maintenance doses (and sometimes also the intervals between injections) adjusted to renal function values. Dosage guidelines in relation to the renal function were established from these data.

Humans↗
PubMed1982

[Comparative biliary excretion of mezlocillin and 12 other beta-lactam antibiotics (author's transl)].

The biliary excretion of mezlocillin was studied on an experimental in vitro model (perfused rabbit liver) and by various methods in man. After addition of 10 mg mezlocillin to blood perfusing isolated rabbit lever preparations (n = 5) during 3 hours, a mean biliary peak of 758 +/- 129 micrograms/ml was recorded between 30 and 60 minutes. The 0-3 h cumulative biliary excretion was 20.3 % of the dose administered. Following a 30 min intravenous infusion of 5 g mezlocillin to 5 healthy subjects, the mean maximal antibiotic activity in the duodenal aspiration fluid was 626.0 +/- 115.0 microgram/ml during the first hour. In 10 cholecystectomized patients with T-tube drainage who received 1 g mezlocillin intramuscularly, a mean biliary peak of 296 +/- 58 micrograms/ml was recorded. The 0-12 h cumulative biliary excretion of the antibiotic was 2.6 % of the dose injected. After intravenous infusion of 5 g mezlocillin, the corresponding values were 505 +/- 118 micrograms/ml and 1.3 % respectively. One hour after rapid intravenous injection of 2 g mezlocillin, the antibiotic activities in samples of serum, common bile duct bile and gallbladder bile collected during cholecystectomy were 28.9 +/- 5.3, 895 +/- 196.1 and 402 +/- 133.2 micrograms/ml respectively. These results were compared with those obtained in similar conditions with 12 other beta-lactam antibiotics.

Animals↗
PubMed1982

Biliary excretion of cefaclor. Experimental and clinical study.

Biliary excretion of cefaclor, a new orally active cephalosporin, was studied in vitro using an isolated rabbit liver preparation perfused for 3 h (n = 5). Under these conditions, bile recovery amounted to 2.3% of the cefaclor dose added to the circulating blood (10 mg). In humans, after oral administration of a 1-gram dose of cefaclor to cholecystectomized patients provided with a T tube (n = 10), a mean biliary peak concentration of 7.6 +/- 2.4 microgram/ml was observed at the 3rd hour. Cumulative biliary excretion amounted to 0.05% of the administered dose. Assays performed on samples collected during cholecystectomy in 10 patients 1 h after intake of a 1-gram dose of cefaclor showed mean concentrations of 13.7 +- 1.2 micrograms/ml in serum, 8.1 +/- 1.3 micrograms/ml in common duct bile and 5.9 +/- 1.4 micrograms/ml in gallbladder bile. These results were compared with the data obtained after administration of seven other cephalosporins studied under identical conditions.

Adult↗
PubMed1982

Pharmacokinetics of mezlocillin in patients with kidney impairment: special reference to hemodialysis and dosage adjustments in relation to renal function.

The pharmacokinetics of Mezlocillin were determined after the intramuscular injection of a single 1-gram dose in 10 subjects with normal renal function, in 10 patients with stabilized renal impairment and in 5 patients with end-stage renal disease submitted to repeated hemodialysis. In normal subjects, biological half-life, Tb1/2, was equal to 0.9 h; total clearance (Ct) to 449 ml/min/1.73 m2; renal clearance (Cr) to 263 ml/min/1.73 m2.72.2% of the administered dose was excreted in the urine within 12 h. In patients with renal insufficiency and in patients undergoing long-term hemodialysis, the serum concentration decrease was markedly slower. During a 6-hour dialysis session, 62% of the Mezlocillin present in the central compartment at the start of hemodialysis was removed. In the 25 subjects under study, a significant correlation was found between the values of Ke and those of creatinine clearance, Ccr (Ke = 0.1973+0.0046 Ccr). This relation was used to calculate the loading doses, the maintenance doses and the dosage intervals adjusted to the degree of renal impairment, allowing assessment of useful dosage recommendations.

Anti-Bacterial Agents↗
PubMed1982

Pharmacokinetic profile of benoxaprofen in subjects with normal and impaired renal function, prediction of multiple-dose kinetics.

The pharmacokinetic profile of benoxaprofen given as a single oral dose of 600 mg was determined comparatively in 5 healthy volunteers and in 15 patients with various degrees of renal insufficiency (5 of whom were undergoing maintenance hemodialysis). In normal subjects, the half-absorption period (Ka) was 0.63 hours. A mean maximum concentration of 47.3 micrograms/ml could be predicted at 3.6 hours after the dose intake. Serum level decrease was particularly slow. The overall elimination rate constant, Ke, was 0.0234(h-1) and biologic half-life amounted to 28.8 hours. Values for total clearance (Ct=4.8 ml/min/1.73 m2) and renal clearance (Cr=1.6 ml/min/1.73 m2) were low. Of the administered dose of benoxaprofen, 13.9% was recovered in the urine over a 24-hour period. Renal insufficiency did not induce major changes in pharmacokinetic parameters. Under such conditions, it seems advisable to reduce the dose to one-half only in patients with a creatinine clearance of less than 10-20 ml/min/1.73 m2. Predicted serum levels theoretically achieved after repeated administration of a 600-mg dose of benoxaprofen every 6, 12, 24, 36 and 48 hours were calculated. From this evaluation, it appears that therapeutically effective and adequate levels could be obtained after administration of a 600-mg dose every 12 ot 24 hours.

Adult↗