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Biomedical subjects

J Barre

Publications and source records attributed to J Barre.

At least 73 records · Page 4Linked to original sources
PubMed1985

Acute haemodynamic effects and tissue distribution of acebutolol in normotensive and spontaneously hypertensive rats.

Acute i.v. administration of 15 mg/kg acebutolol in normotensive (WKY), Okamoto (SHR) and Okamoto stroke-prone (SHR-SP) awake rats resulted in weak effects on blood pressure and in bradycardia more marked in SHR-SP. Thirty minutes after i.v. administration, lung and renal uptake of [14C]acebutolol was reduced in SHR compared to other rats. Muscle uptake was higher in SHR and blood concentration was higher in SHR-SP. Brain levels were low and similar in all rats. Plasma protein binding was identical in all rats. These results are discussed according to the characteristics of the three strains studied.

Acebutolol↗
PubMed1985

[Biological diagnosis of postoperative thrombopenia].

The recognition of the postoperative thrombopenia is important because thrombopenia give an hemorrhage risk and modify the tolerance to preventive anticoagulant treatments. Some thrombopenias can be iatrogenic: thrombopenias by transfusion of a large volume of preserved blood, or by hemodilution, but require a substitution, therapy are easily diagnosed. Post-transfusional thrombopenias require an antibody analysis (especially for antiPLA1). The search for drugs interactions is often complex; heparin induced thrombopenia constitutes a severe but fortunately a rare complication of the heparin therapy. Other thrombopenias are related to operative complications this is the case of consumption-coagulopathies due to infections, the release of thromboplastin from tissues, hepatic cirrhosis, pancreatitis, etc. The evaluation of hemostasis verifies clinical hypotheses and guides the treatment. Thrombopenias can be due to various disorders revealed or occurring during an operation. Although the concurrences are rare, they do not always preclude the possibility of finding a collagen disease (connectivitis), a thrombocytogenetic thrombotic purpura, and especially an idiopathic thrombopenic purpura. In any case, diagnosis is easier if the preoperative platelet levels are known. Thus, platelet counts should be included in pre and postoperative evaluations.

Antigen-Antibody Complex↗
PubMed1984

Dose-dependent pharmacokinetic study of pefloxacin, a new antibacterial agent, in humans.

A dose-dependent pharmacokinetic study of pefloxacin was performed after four intravenous infusions and four orally administered doses. After intravenous infusion, the pharmacokinetic profiles of the plasma concentrations showed a biphasic decline, with half-lives (mean +/- SD) of 8.55 +/- 4.20 min and 11.50 +/- 1.75 h, respectively. Intravenous infusion and oral administration yielded similar results. The pharmacokinetic parameters remained constant in the dose range of 200-800 mg from the plasma and urine data.

Administration, Oral↗
PubMed1984

Absolute intramuscular, oral, and rectal bioavailability of alizapride.

A study was designed to estimate the absolute bioavailability of alizapride after intramuscular injection, oral administration as a solution or a tablet, and rectal administration as a suppository compared with that after intravenous injection. A balanced incomplete block-design trial was adopted. The intramuscular injection and the tablet administration showed identical results with those of the intravenous injection. On the contrary, the oral solution and the rectal suppository dosage forms gave lower absorption values, i.e., 75 and 61% of the dose administered was absorbed, respectively.

Administration, Oral↗
PubMed1984

Influence of food on the absorption of the p-chlorophenolic ester of chlorophenoxyisobutyric acid in man.

A study was designed to investigate the effect of a fatty meal on the absorption of chlorophenoxyisobutyric acid (CPIB) in six healthy adult volunteers after oral administration of the p-chlorophenolic (PCP) ester of CPIB. Plasma concentrations of CPIB when administered with food were higher than those observed in the fasting state. The Cmax in the former case was 24.0 +/- 4.6 mg l-1 as against a value of 15.2 +/- 6.9 mg l-1 in the latter (P less than 0.01). The pharmacokinetic parameters measured were found to be linear with the dose administered. This could be due to low plasma concentrations of CPIB unable to cause a saturation of the plasma protein binding of this drug. It is concluded that a fatty meal enhances the absorption of this hypolipidaemic drug.

Adult↗
PubMed1984

Pharmacokinetics of butofilolol (CAFIDE) after repeated oral administration in man.

The pharmacokinetics of butofilolol, a new beta-blocking drug, was studied in 6 healthy subjects. Plasma concentrations and urinary excretion of the unchanged drug were determined after a single 100-mg oral administration, and also during chronic treatment (100 mg/day for a week) and after the last dose. Maximum plasma concentrations were observed 2 to 3 h after drug administration and varied between the subjects (120 to 430 ng/ml). The apparent volumes of distribution were large, ranging between 200 I and 500 I, and the apparent clearances of elimination appeared to be intermediate between 40 and 70 l/h. Drug elimination in the urine (about 4% of administered dose) occurred by filtration, tubular secretion and pH-sensitive reabsorption following a non-linear process. However, pharmacokinetic parameters remained constant during chronic treatment, since urinary elimination of the parent drug was too low to influence its pharmacokinetic profile. In addition, a high correlation was found between plasma levels of butofilolol and the effect of the drug on resting heart rate, while a slight effect on diastolic blood pressure could be discerned.

Administration, Oral↗
PubMed1984

[Comparison of bacteriological and immunoenzyme methods for the serum determination of sisomicin. Pharmacokinetic application in the human].

A modification of the serum gentamicin immunoenzymatic method (Syva- Biom erieux kit) for sisomicin assay is proposed and compared to the bacteriological reference method. It shows a higher sensitivity (0.1 mg.l-1) with a shortened time of analysis (less than 1 hour) and a good reproducibility (range: 4.7% to 1.6% for concentrations between 0.5 mg.l-1 and 10 mg.l-1) but the concentrations are 15 p. cent lower as compared to the bacteriological method. A pharmacokinetic study, performed in five patients, enables us to demonstrate the praticability of this method for the adaptation of the dosage regimen in renal insufficiency.

Biological Assay↗
PubMed1983

Binding of clometacin to human serum albumin. Interactions with clofibrate, indomethacin, salicylic acid and warfarin.

The binding of clometacin to human serum albumin (HSA) was studied in vitro by equilibrium dialysis. Our results show that binding to HSA is 99% at therapeutic levels. Binding is characterized by several numbers of binding sites (n = 8) with a moderate association constant (K = 2.7 X 10(4) M-1) and by another non-saturable phenomenon (nK = 4200 M-1). Moreover, interactions were studied with many drugs. Clometacin binding was altered by indomethacin, warfarin, chlorophenoxyisobutyrate (CPIB) and salicylic acid (SA). Conversely, clometacin inhibited the binding of these drugs. Finally, all these results were compared with those previously obtained with indomethacin, a positional isomer of clometacin.

Analgesics↗
PubMed1983

Disease-induced modifications of drug pharmacokinetics.

This article attempts to help in the understanding of the mechanisms responsible for a modified drug pharmacokinetic profile in disease states. The main factors influencing the fate of the drug as it moves from the site of administration to the sites of elimination are depicted. Changes in absorption kinetics can be due to altered gastrointestinal peristalsis and secretions as well as modifications of splanchnic blood flow. Pathological states may affect the binding of drugs to plasma proteins, mainly human serum albumin and alpha 1 acid glycoprotein. The resulting modifications in the free fraction of the drug can cause a change in the volume of distribution. The distribution can also be influenced by circulatory disorders modifying local blood flows and thus impeding drug entry into the tissues. Many diseases can alter hepatic and/or renal clearance. This is not surprising since the elimination mechanisms are dependent upon many factors such the enzymatic status of the liver, plasma protein binding, and blood flow to both the liver and the kidney. Some examples such as the modification of furosemide pharmacokinetics in acute renal failure, the impaired metabolism of opiate analgesics in hepatic insufficiency, the alterations of the usual disposition process in salicylic acid intoxication, and the influence of cardiac failure upon some drugs pharmacokinetics, have been chosen to illustrate some of the aspects discussed. Some simple rules for making a rational selection of drugs in pathological states are also outlined.

Acute Kidney Injury↗
PubMed1981

Evidence for a concentration-dependent polymerization of a commercial human serum albumin.

Polymerization of a commercial human serum albumin (Sigma A-1887) was investigated by two different techniques, high-performance liquid chromatography and gel electrophoresis. The chromatographic technique was based on the frontal analysis principle using a column which excludes polymers but retains monomers. The results allowed the determination of the monomer--polymer affinity constant, X = 526 +/- 100. The electrophoresis technique was performed with a polyacrylamide gel containing sodium dodecyl sulphate in order to separate the different polymer species according to their molecular weights. The two techniques gave results in good accordance and showed a concentration-dependent aggregation. The higher the human serum albumin concentration, the more the monomer proportion decreases.

Chromatography, High Pressure Liquid↗
PubMed1981

[Interference of anaesthesia and transfusion on rheological parameters (author's transl)].

This study was designed to investigate the rheological and plasmatic parameters from multiple transfused patients and patients undergoing surgery non transfused. Blood filtrability compared with the erythrocyte electrophoretic mobility shows the perturbance resulting from the delay of conservation and the importance of the transfused blood. The 2-3 DPG, ATP and oxygen-hemoglobin affinity suggest the excellent recuperation of the erythrocyte metabolic function in vitro. The rheological parameters seems to be a good mean in the supervision of red massive transfusion blood cell.

Adenosine Triphosphate↗
PubMed1980

Binding of erythromycin base to human plasma proteins.

The binding of erythromycin base (EB) to human plasma (HP) proteins was measured by equilibrium dialysis using EB-14C at approximately 0.5 microgram/ml in the plasma phase, expected therapeutic concentration. EB was 64.5 +/- 0.4% (mean +/- S.D.) bound to HP. The percentage of bound EB was linearly related to the logarithm of HP dilution. Physiological concentrations linearly related to the logarithm of HP dilution. Physiological concentrations of human serum albumin (HSA) and a1 acid glycoprotein (a1AGP) bound 8.7 +/- 1.6 and 54.5 +/- 0.6%, respectively, of the drug. No binding of EB to HDL or LDL or human gamma globulins was found. For HSA separately, EB binding followed a non-saturable phenomenon with n'K' = 100 +/- 5, while for a1AGP the binding was following a saturable phenomenon with n" = 1 +/- 0.045, K" = 35,000 +/- 5000 M-1. It can then be shown that, in human plasma, EB is only bound to those two proteins: firstly by computing the binding of EB to HSA and a1AGP with the previously indicated parameters, and secondly by measuring the binding of EB to HP. The computed curve fairly fits to the measured one. Interaction of EB with HP involved hydrophobic, ionic and hydrogen forces. Lower than 37 degrees C temperatures decreased EB binding. Significant competitive binding was demonstrated between EB and acetylsalicylic acid, furosemide, phenylbutazone, warfarin and bilirubin.

Aspirin↗