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Biomedical subjects

P Lapalus

Publications and source records attributed to P Lapalus.

At least 91 records · Page 5Linked to original sources
PubMed1986

[Rapid microdetermination of 2 aminoglycosides by high-performance liquid chromatography in the plasma, bile and urine. Correlation of high-performance liquid chromatography and fluorescence polarization for plasma assays].

An HPLC method for determination of dibekacin and amikacin in various biological samples is described. A step gradient elution and fluorescence detection carried out through an on line post column derivatization system with OPT is used. The chromatographic conditions allow simple and rapid preparation, so that a result can be obtained within twenty minutes. The small volume required (150 microliters) and the rapid sample clean-up are advantageous for routine use even in pediatric patients. The good sensitivity (dibekacin: 0,44 mumol/l - amikacin: 0,35 mumol/l), reproducibility and specificity indicate it to be suitable for pharmacokinetic studies. Results obtained from HPLC were in excellent agreement with those of FPIA for both dibekacin and amikacin (r greater than or equal to 0,98).

Amikacin↗
PubMed1986

[Effects of chromocarb diethylamine and prednisolone in experimental uveitis induced by clove oil in rabbits].

Clove oil injection in the anterior chamber of the rabbit eye produces an uveitis and a disruption of the blood-ocular barrier which can be evaluated by the leakage of 125I-radiolabelled rabbit serum albumin (RSA) administered intravenously. In the normal rabbit eye the amount of RSA in the aqueous humor is quite small. The disruption of the blood-ocular barrier by clove oil injection increases the RSA level in the anterior chamber of the eye. Topically applied chromocarb diethylamine reduces significantly the disruption of the blood-ocular barrier in the inflamed eye. Despite of its lack of anti-inflammatory activity, this compound, as a 10% eye-drop formulation, was shown nearly as effective as prednisolone 0.1%, in the corneal edema and the disruption of the blood-ocular barrier.

Animals↗
PubMed1985

[Monitoring of treatment involving 5-fluorocytosine].

The occurrence of hematologic and neurologic complications probably caused by an overdose of 5-FC has prompted us to study 5-FC pharmacokinetics in 10 patients under a 5-FC and amphotericin B. On the basis of our findings we have determined the optimal dosage that achieves desired concentrations. In 5 cases this dosages was found to differ from that suggested by the manufacturer. 5-FC concentrations were however higher than predicted levels as a result of the association with amphotericin B. A subsequent modification of dosage was needed in 10 patients. 5 undesirable side effects were recorded: thrombopenia (1 case), neutropenia (1 case), diarrhea (2 cases), and isolated rise in transaminases. In 4 patients with high 5-FC concentrations, chromatograms showed a peak possibly formed by 5-FU, suggesting that 5-FC may be converted into 5-FU.

Amphotericin B↗
PubMed1984

Pharmacological characteristics of beta-adrenergic-sensitive adenylate cyclase in non pigmented and in pigmented cells of bovine ciliary process.

Adenylate cyclase activity was studied on the two epithelial cell types of bovine ciliary process after digestion by trypsin and purification by density gradient centrifugation. cAMP formation after isoproterenol stimulation showed that non pigmented cells were particularly enriched in adenylate cyclase activity. Furthermore pharmacological characteristics of this enzyme indicated that adenylate cyclase-associated beta adrenergic receptors were of beta 2 type in each kind of epithelial cells. These results support the hypothesis that beta adrenergic compounds modulate aqueous humor production through a direct effect on ciliary epithelium and enrichment of beta adrenergic sensitive adenylate cyclase activity in non pigmented epithelial cells suggests that these particular cells may play an important role in aqueous humor secretion.

Adenylyl Cyclases↗
PubMed1984

Characterization of beta adrenergic receptors in bovine pigmented ciliary processes.

To analyse the molecular mechanism of action of beta-adrenergic compounds in reducing the intraocular pressure, the binding of 125I-iodohydroxybenzylpindolol to bovine pigmented ciliary processes was studied. The binding was found to be highly specific, saturable, reversible and displayed stereospecificity. Only one class of binding sites was detected. Values for KD of 0.18 nM and 0.32 nM were derived from kinetic and equilibrium experiments, respectively. The total number of beta receptors was large : 1.28 pmoles/mg protein. Competitive inhibition of 125I-iodohydroxybenzylpindolol binding by agonists and antagonists revealed that the majority of beta receptors in bovine pigmented ciliary processes were of the beta 2 type. The pharmacological and biochemical characteristics of the binding of adrenergic drugs found in these membranes are consistent with a regulation of aqueous humor production by the beta adrenergic system.

Adrenergic beta-Agonists↗
PubMed1983

[The effect of various diseases on the zinc plasma level].

Zinc, an important enzymatic cofactor, takes part in numerous metabolic pathways. In man, zinc deficiencies may be due either to deficient absorption or to excessive use. In this study in 285 patients hospitalized in a department of internal medicine for acute or chronic conditions, serum zinc assays have shown the following results: serum zinc concentrations are significantly decreased in acute critical conditions (cardiovascular ischemic disorders, heart failure, infections); in chronic conditions, serum zinc is decreased in some instances (renal failure, cancer, alcoholism, diarrhea), while it remains normal in others (compensated heart failure, non-insulin dependent diabetes, arterial hypertension, obesity). The fall in serum zinc concentrations is usually correlated with the severity of the clinical condition.

Acute Disease↗
PubMed1982

[The theophylline test. Indications for the effective daily dosage (author's transl)].

The great variability in the metabolism and degradation of theophylline in different people demands an individual dosage to be effective; this is to maintain the theophylline levels between the threshold of therapeutic activity (10 mg/L) to the upper limit of tolerance (15 to 20 mg/L according to different studies). The effective individual doses may be determined before commencing treatment by a Theophylline Test. This allows the dose over 24 hours to be specified as well as the number of tablets necessary to maintain the theophylline levels in the chosen range. The principle of the Theophylline Test is to administer intravenously a test dose of theophylline, then with 5 successive samples for blood theophylline to assess the individual elimination of the drug. For each subject two pharmacokinetic parameters are determined: clearance and plasma half life. The plasma clearance allows the total dose over 24 hours to be calculated, the half life the number of doses and the type of preparation used: microkrystalline theophylline (Techniphylline), slow release theophylline (Theophylline Bruneau) and prolonged action theophylline (Armophylline).

Adolescent↗
PubMed1982

[Adaptation of the oral dosage of theophylline to the asthmatic child. Value of a kinetic test by the intravenous route].

The authors propose a practical method for determining chronic oral theophylline dosage in children from slow intravenous theophylline infusion (45 minutes). Calculated clearances and half lifes provided a basis for daily oral theophylline doses and dosing intervals. Pharmacokinetic characteristics (mean +/- SD) in 34 asthmatic children (age range 2-14 years) averaged 0.082 +/- 0.028 l/kg/h for Cl; 0.436 +/- 0.087 l/kg for Vd; 4.07 +/- 1.43 h for t 1/2. Calculated daily dosages necessary to maintain mean serum theophylline concentration of 12.5 mg/l ranged from 9.6 to 40.9 mg/kg/d (average 24.5 mg/kg/d). The validity of proposed dosage schedules is studied in 11 children (among the 34 patients) undergoing a chronic theophylline treatment either with rapid absorption products, or sustained-release form. The difference between predicted and effective serum concentrations was within +/- 1.8 mg/l in all cases.

Administration, Oral↗
PubMed1982

[Candida albicans spondylitis. Review of the literature apropos of a case with study of bone penetration of 5-fluorocytosine].

In spite of the development in cases of deep mycoses, cases of osteoarthritis with Candida remain rare (only thirty seven cases reported). Among these, ten observations of spondylodiscitis have been collected and the authors report a new case where Candida albicans was isolated in the discovertebral focus through bone puncture. This spondylodiscitis occurring in a leukemic patient receiving antibiotics, corticosteroids, cytostatics drugs and radiotherapy, was treated successfully by an association of Amphotericin B-5-Fluorocytosine. The authors take this opportunity to report the main characteristics of the ten previously described cases specifying the rules for the uses of fungicidal drugs in the treatment of deep mycoses and for the first time, they study simultaneously seric concentration, penetration into healthy bone and into discovertebral focus of the 5-Fluorocytosine. They also justify their preference for the association of Amphotericin B-5-Fluorocytosine as a "first line" treatment after confirming the sensitivity of the strain to 5-Fluorcytosine.

Amphotericin B↗
PubMed1981

[Clinical value of the determination of serum digoxin levels (author's transl)].

The authors refer to the technique of the serum digoxin enzyme immunoassay, and they report the results of 297 dosages concerning 111 hospitalized patients. The normal plasmatic rates are of 1,4 +/- 0,6 microgram/l in patients who present no sign of digitalic overdosage. The rates are of 5,2 +/- 1,6 microgram/l in cases of intoxication. The difference between these rates is greatly significant (p less than 0.001). The limit between therapeutic and toxic rates is situated around 3 microgram/l with an overlapping from 2 to 3 microgram/l. Authors then examine the individual factors that intervene in digoxin metabolism and especially study the influence of age, myocardic factors and renal insufficiency. On the basis of these results and review of the literature, they emphasize the interest of serum digoxin determination in the diagnosis of digitalis toxicity, as well as in the management of high risk patients, and of cardiopathies difficult to stabilize.

Aged↗
PubMed1979

Induction of cataracts in the rat by derivatives of (4' -pyridyl) - 1 piperazine.

A structure ocular toxicity study in the rat of (4' - pyridyl) - 1 piperazine and of some derivatives with psychopharmacological profile, allows some interesting conclusions. (4' - pyridyl) - 1 piperazine does not lead to crystalline lens opacity, though some aryloxypropanol or aryloxypropyl derivatives do. At least, (2' - pyridyl) - 1 piperazine and one aryloxpropanol derivative do not improve cataract. So the appearance of cataracts is probably due to substitution of an alkylaryl side chain on the N-4 position of (4' - pyridyl) - piperazine.

Animals↗