[Evaluation of Emit netilmicin and amikacin assays on Dimension RXL HM (Dade Behring) open channels]. / Adaptation des trousses Emit nétilmicine et amikacine sur canaux ouverts du Dimension RXL HM (Dade Behring).

The aim of this study was to evaluate and to validate an enzyme immunoassay in homogeneous phase for netilmicin and amikacin, adapted on the Dimension RXL HM (Dade Behring) machine. The results were compared with those obtained with automated polarization of fluorescence immunoassay using TDx FLx (Abbott). The protocol of the study and the analytical criteria were inspired by the protocol Valtec version 2002 recommended by the French Society of Clinical Biology (SFBC). The validation of this technique as adapted to the Dimension RXL HM has allowed its use for routine dosage adjustment of amikacin and netilmicin. The practicability is however the weak point of the adaptation of these techniques, even limiting as for their implementation.

Population pharmacokinetics of cisplatin in patients with advanced ovarian cancer during intraperitoneal hyperthermia chemotherapy.

The objective of this study was to determine the pharmacokinetic profile of total platinum administered by hyperthermic peritoneal perfusion (HPP) in 16 patients with ovarian cancer. The patients had a performance status of lIIalpha/b/c on the FIGO scale. They received 60, 80 or 100 mg of cisplatin. The percent of cisplatin remaining in the body after the peritoneum was emptied averaged 65% (41.7-85.4%). The average ratio between peritoneal drug concentrations and plasma concentrations was 73. A Bayesian estimation of individual phamacokinetic parameters was carried out using the non-linear mixed-effect modeling approach as implemented in the NONMEM computer program. A two-compartment model with an additional peritoneal cavity compartment was used to fit the data. Large interindividual variability of the pharmacokinetic parameters occurred The maximum platinum concentration in plasma was reached between 1 and 1.5 hours after the beginning of administration; it ranged from 0.37 to 1.7 microg/ml (1.9 to 8.72 microM). The elimination half-life was 80 hours (48-152 hours and the area under the plasma concentration time curve normalized to a 100 mg cisplatin dose was 79 mg/liter x hours. The simultaneous fit of perfusate and plasma concentrations allowed us to estimate the percent of cisplatin that reached the systemic circulation at about 20%. At time infinity, the urinary cisplatin recovery accounted for only 20% of the administered dose. The results in this study showed that a high proportion of the cisplatin dose was absorbed by target tumor cells. In spite of the advanced disease of patients at the time of HPP, 37.5% of them were still alive three years after HPP (ie., 3-6 years after cancer diagnosis) and 12.5%, 7 years after HPP (i.e., 8 years after cancer diagnosis).

Oxidants and antioxidants in long-term haemodialysis patients.

Survival for decades is now possible in end-stage renal disease patients (ESRD) treated with haemodialysis (HD). Long-term survivors may present dialysis-related pathology (DRP). Alterations in lipid metabolism and oxidative stress are recognized as important risk factors that could be prevented or reduced by optimal therapy. We have studied markers of oxidative stress in patients receiving HD treatment for more than 20 years. In order to evaluate a preventive intervention against oxidative damage we measured the factors implied for the prooxidative and antioxidative mechanisms in haemodialysis patients. Ten long-term HD survivors (HD duration: 274.2 months) and ten patients with recent onset of HD (HD duration: 17.8 months), had blood drawn for plasma vitamins A and E, malondialdehyde (MDA), plasma and RBC glutathione peroxidase (GPx), RBC superoxide dismutase (SOD), plasma and erythrocyte glutathione reductase (GSSG-R), oxidized and reduced glutathione (GSH) assessment. Despite normal levels of antioxidant vitamins, an usual finding in this setting, increased MDA, and oxidized GSH, and decreased plasma GPx and reduced GSH show that oxidant stress is markedly present in both recent onset and long-term HD patients. It would appear highly advantageous to reduce complications of long-term dialysis patients with preventing modalities.

[Value of the Remedi chromatography automate for the analytic diagnosis of drug poisoning]. / Intérêt de l'automate de chromatographie Remedi pour le diagnostic analytique des intoxications médicamenteuses.

The aim of this study was to evaluate the liquid chromatographic system Remedi (Biorad) in comparison with traditional immunological and colorimetric methods, for the diagnosis of acute drug overdose. 469 blood samples and 95 stomach cleaning liquid samples have been analysed during 1995. The usual toxicologic analysis was composed of the benzodiazepines, tricyclic antidepressants and barbiturates research. Ethanol, meprobamate and acetaminophen assays were performed only on physician's request. Only three pharmacological classes can be analysed both with immunological methods and Remedi: benzodiazepines, tricyclic antidepressants and barbiturates. Remedi has been found to be less sensitive than immunological method for benzodiazepines, it sometimes gave false negative results for barbiturates, but it was very efficient for antidepressants. Remedi often identified drugs other than the 3 previous classes: sedatives, antipsychotic, beta-blockers, antiarythmics. Furthermore these drugs are of clinical importance due to the fact that they are able to modify the symptomatology. In every case Remedi was able to give an estimation of the blood concentration of the toxic molecule matched. Remedi can not replace traditional methods but is a good complementary tool, available in emergency. This is particularly useful when clinical signs do not correspond to the toxics suspected by questioning the patient or relatives.

[Method selected for the determination of creatinine in plasma or serum. Choice of optimal conditions of measurement]. / Technique sélectionnée pour le dosage de la créatinine dans le plasma ou le sérum, Choix des conditions optimales de mesure.

The method selected by the SFBC (Société française de biologie clinique) is derived from the colorimetric reaction of creatinine with alkaline picrate, measured kinetically, without any pretreatment step. The key parameters of the reaction determining the quality of the results are studied, with special regard to samples including known interferents. The aims of the study were to gain an optimal analytical sensitivity and to reduce main interferences (acetoacetate, bilirubine, glucose, protein) which plague the Jaffé reaction, through a comprehensive study of the reagents, of their concentrations and of the analytical procedures. The selected concentrations (in the test) are: 150 mmol/L sodium hydroxide, 10 mmol/L picric acid and 2 g/L sodium dodecyl sulfate. Ten millilitres of a BRIJ solution (30% volvol) are added to the reagent. The operating procedures are as follow: sample ratio 0.07 to 0.08; wavelength 505 to 510 nm; temperature 37 degrees C; incubation of the specimen with the alkaline reagent 5 mn (at least), before starting the reaction with picric acid. A seric calibrator is recommended. The first measurement is taken 20 to 40 s after starting the reaction. Total measurement time is 120 to 150 seconds.

[Validation and study of the transferability of the selected technique by SFBC for the determination of creatinine in plasma]. / Validation et étude de la transférabilité de la technique sélectionnée par la SFBC pour le dosage de la créatinine dans le plasma.

A selected method for the determination of creatinine in plasma, using the reaction with alkaline picrate without prior pretreatment has been proposed by the Commission 'Validation de techniques' in the SFBC (Société Française de biologie clinique). The transferability step was conducted in seven laboratories, equipped with different automatic analyzers, using analytical procedures derived from the recommended method. Its goal was to test whether the original analytical performances could be maintained and consistent results obtained. The validation step was designed to evaluate the linearity limits of the analytical range, the detection limit, to assess accuracy as compared to a high performance liquid chromatography and to investigate the effect of the main interferents. Linearity limits are 15 and 2000 mumol/L. The detection limit is 3 to 8 mumol/L according to the analytical systems. The selected method can fulfil the set imprecision goals: intralaboratory CV minus than 2% (within-run), minus than 4% (run-to-run), interlaboratory CV minus than 5% (for 100 mumol/L creatinine). Inaccuracy evaluated for the chosen control sera is 1 to 15% as compared to the chromatographic method, according to the sera and to the analytical systems. The results obtained with the selected method are more consistent with the HPLC than are those obtained with an alkaline picrate method without SDS or with an enzymatic method. No interference could be demonstrated for acetoacetate (up to 8 mmol/L), hemoglobin (up to 210 mumol/L), unconjugated bilirubin (up to 250 mumol/L), glucose (up to 30 mmol/L), IgG (up to 45 g/L), albumin (up to 60 g/L). The effect of cephalosporins depends on the molecule. The reagents are stable for at least 6 months when stored in closed vials at +20 degrees C. The alkaline reagent is stable 30 days at +4 degrees C. Reference limits (0.025 and 0.975 fractiles) have been established for healthy adults. They are respectively 73 to 126 mumol/L for men and 59 to 100 mumol/L for females.

Creatinine metabolism impairment by an anticonvulsant drug, phenacemide.

OBJECTIVE: To report two cases of increased true serum creatinine (Scr) without renal failure caused by an anticonvulsant drug, phenacemide, and to discuss the possible mechanisms. CASE SUMMARY: Two patients treated with phenacemide were investigated for markedly increased Scr and decreased creatinine clearance (Clcr) values. Glomerular filtration rates, as determined by 125I-iothalamate clearance, were normal in both patients and analytical interferences with the Jaffé reaction were excluded. After discontinuation of the drug, phenacemide concentrations became undetectable within 2 days but it took 7-14 days for Scr and Clcr to return to normal values. DISCUSSION: The Scr increase with phenacemide (120-170 percent) was higher than that reported with cimetidine or trimethoprim (10-40 percent) and could not be explained solely by inhibition of the tubular secretion of creatinine. The hypothesis of an overproduction of creatinine caused by phenacemide was ruled out by experimental studies in rats. Creatinine increase in tissues was lower than that in the serum of rats given phenacemide. In vitro creatinine influx into red blood cells was inhibited in a dose-dependent way by phenacemide. CONCLUSIONS: Increased Scr concentrations in these patients could be related to an inhibition of transport and a decrease in creatinine volume of distribution. Creatinine concentrations should not be considered when dosage adjustments of renally eliminated drugs are being calculated for patients with such metabolic interferences.

[Critical value of bilirubin in the selection of healthy volunteers in for phase I]. / Valeur seuil de la bilirubine pour la sélection des voloñtaires sains en phase I.

10% of young male healthy volunteers have a total bilirubin value over 20 mumol/l; thus such a value appears not relevant as screening cut off point in clinical pharmacology. This study was intended to confirm if a 27 mumol/l cut off point previously defined by the authors does not support a risk. This study dealt with 487 subjects who had together measurements of total bilirubin value and lab. tests of liver cytolysis, cholestasis or hemolysis during the selection process. 48 subjects (9.8%) had a total bilirubin value over 20 mumol/l. Correlation tests do not provide arguments of cytolysis, cholestasis or hemolysis and there was no argument in favor of Gilbert's syndrome. Out of 48 hyperbilirubinemic subjects only 22 were included in clinical pharmacology studies. In more than 60%, the total bilirubin value returned to normal spontaneously and in no case appeared a significant clinical, biological, pharmacokinetic or dynamic abnormality. Except a possible increase of slow acetylor frequency, the medical literature analysis does not show any relevant modification in metabolism, pharmacokinetics or pharmacodynamics until a 40 mumol/l value of total bilirubin. Thus, the 27 mumol/l value of total bilirubin previously proposed is confirmed as a useful limit that does not lead to an additional risk.

Biochemical modifications in the blood and the heated fluids during intraperitoneal chemohyperthermia.

The biochemical changes in blood during intraperitoneal chemohyperthermia (IPCH) were examined by carrying out complete assessments before and after the operation. These assessments were made up of 23 parameters: Na, K, Cl, CO2, urea, creatinine, proteins, glucose, calcium, phosphates, magnesium, bilirubin, uric acid, lactic acid, CRP, ASAT, ALAT, CK, LDH, gamma-GT, ALP, lipase, and amylase. Only 5 of these parameters showed significant changes: proteins, urea, ALP, gamma-GT, lactic acid. The protein and urea levels decreased due to hemodilution induced by the perfusion of fluids. ALP and gamma-GT levels decreased, possibly due to localized inhibition of secretion. Lactic acid levels increased due to the movement of lactates from the heated fluid into the blood. The study of biochemical changes within the heated fluids was made using the following parameters: CA 125, CA 19-9, CEA, ASAT, ALAT, CK, LDH, gamma-GT, ALP, lipase, uric acid, phosphates, proteins, Na, K, Cl, urea, creatinine, and magnesium. Between the beginning and the end of IPCH, significant increases were found in the levels of CA 125 (+173%), proteins (+190%), ASAT (+130%), LDH (+103%), K+ (+232%), PO4 (+134%), and uric acid (+99%). These increases indicate the existence of a significant degree of cellular lysis.

Simultaneous high-performance liquid chromatographic assay of droperidol and flunitrazepam in human plasma. Application to haemodilution blood samples collected during clinical anaesthesia.

A simultaneous assay for droperidol and flunitrazepam by high-performance liquid chromatography has been developed and applied to blood samples collected during an acute normovolemic haemodilution under general anaesthesia. Haemodilution blood samples were stored at +4 degrees C to be transfused, if required, to a patient during the post-surgical phase. A C18 Supelclean cartridge was used for solid-phase extraction, and the recoveries were 74% and 89%, respectively, for droperidol and flunitrazepam. Compounds were chromatographed on a C18 Novapak column at 250 nm, with a mobile phase of acetonitrile-10 mM ammonium acetate buffer (pH 6.7) (45:55, v/v). Nitrazepam was used as the internal standard. For both drugs, the assay was linear up to 500 micrograms/l, and the detection limits were 20 and 10 micrograms/l for droperidol and flunitrazepam, respectively, and their observed levels in haemodilution samples were 93 +/- 82 micrograms/l and 76 +/- 107 micrograms/l, respectively. Some of the values for flunitrazepam were higher than the minimal efficient concentration, defined as the plasma level observed at the time of the patient wakening from anaesthesia (12 +/- 4 micrograms/l). According to our results, haemodilution sampling can be performed before induction of anaesthesia. When the blood is collected after the anaesthetic induction, it seems necessary to determine levels of the two drugs in haemodilution samples to avoid side-effects.

[Serum creatinine assay: results of a multicentric study with 16 analytical systems]. / Dosage de la créatinine sérique: résultats d'une étude multicentrique de 16 systèmes analytiques.

During a multicenter evaluation, 16 methods for creatinine measurement have been tested according to the guidelines of the Société française de biologie clinique (SFBC) protocol. Kinetic Jaffé methods, widely used in France, performed on different analytical systems (Astra Beckman, IL 508, RA 1000 Technicon, Hitachi 704, 705, 717 Boehringer, Fara Roche, Progress Kone, Kem-O-Mat Coulter, Perspective France Monitor) have been compared to a continuous flow method with aqueous standards, to enzymatic methods using creatinine amidohydrolase with a colorimetric measurement (Boehringer and Ektachem Kodak) and to an HPLC method. Reproducibility, estimated with four different control sera, proved to be unsatisfactory in some cases as compared to current criteria for imprecision (less than +/- 10 mumol/l for intralaboratory and less than +/- 20 mumol/l for interlaboratory imprecision). The same selected patients sera covering the whole range of physiopathological concentrations have been analyzed with each method, and compared with the continuous flow results. Differences are more dependent on the sample than on the calibrators. The influences of haemolysis, bilirubin, acetoacetate, albumin, lipids, glucose, and some cephalosporins have been evaluated with spiked human sera. Haemolysed, turbid and jaundiced patient samples have been analyzed as well. The results vary according to the analytical procedure. This study took place in the implementation of a selected method for routine purpose with special regards to interferences and an acceptable imprecision. The method must satisfy the physicians' demands in the renal function exploration, especially in kidney-transplant patients.

[Update of a selected technique for uric acid determination in plasma and serum. Experimental study and value of derivative spectrophotometry]. / Mise au point d'une technique sélectionnée de dosage de l'acide urique dans le plasma et le sérum. Etude expérimentale et intérêt de la spectrophotométrie dérivée.

A critical study of the candidate reference method for evaluation of uric acid in plasma proposed by the American Association of Clinical Chemistry is followed by testing in six laboratories. The dispersion of results is wide (CV greater than 5%). The importance of turbidity remaining after the deproteinization by trichloracetic acid is clearly demonstrated. This turbidity is really not reproducible from an operation to another one on the same serum. It is very likely responsible of the great dispersion of the results. After that, other deproteinization methods are tried. Ultrafiltration and ultracentrifugation give both defect errors because uric acid is in part bound to proteins. So it is necessary to find another technic which cancels the effects of turbidity on the absorbance readings in the ultra-violet domain. Experimental studies showed that uric acid may be evaluated with a good accuracy by derivative spectrophotometry, in lipid solutions as well as in cloudy ones. Turbidity was created by intralipid suspension additions. Various parameters hitting the method were examined (linearity, smoothing window...), taking as criterion the measure of overloaded serums at different levels. At last, the method is successfully transferred in several sites. In the case of blood serum, the respective influences of derivation and of repetition of final centrifugations are studied in order to estimate the effect of remaining turbidity. By the use of derivative spectrophotometry the improvement of the method of evaluation of uric acid proposed by A.A.C.C. is very noticeable; it reduces the variation coefficient between sites to less than 2%.

[A recommended method for determination of uric acid in serum]. / Méthode recommandée pour le dosage de l'acide urique dans le sérum.

SFBC work group on uric acid propose a method for evaluation in blood serum which is modeled on the one defined by American Association for Clinical Chemistry. Serum is deproteinized by trichoracetic acid and the supernatant, buffered to pH 8.5, is submitted to uricase action. The disappearing of the strong band of uric acid in UV is measured by derivative spectrophotometry; this procedure vanished the effect of trouble which remains in the supernatant. This spectrophotometric technic permit to reach, in multiple sites, a variation coefficient near of 1 p. cent.

[Evaluation of enzymuria as a tracer in nephrotoxicity: results of a multicenter study]. / Evaluation de l'enzymurie comme marqueur de néphrotoxicité: résultats d'une expérience multicentrique.

Urinary excretion of three enzymes of different subcellular location in kidney tissue, alanine aminopeptidase (AAP), gammaglutamyltransferase (GGT), N acetyl-beta-D glucosaminidase (NAG), was carried out in 79 healthy adults and 108 healthy children and in 69 adults with various therapies: antibiotics (32 cases), non steroidal anti-inflammatory drugs (NSAIDs) (22 cases), cisplatinum (12 cases) and cyclosporine (3 cases). A circadian rhythm has been shown in children. In patients treated with antibiotics, the importance and duration of the increased enzymes urinary excretion were variable but the excretion of AAP was always higher than that of GGT and NAG. Short term therapies by NSAIDs were without influence on enzymuria but long term therapies produced a moderate increase of NAG excretion. Enzymuria increased immediately after cisplatinum administration and decreased after each daily dose, except in patients with previously high creatininemia. Cyclosporine induced a slight increase in AAP and NAG excretion. Enzymuria, thus, increased early reflecting a toxic effect of the drug at the cellular level whereas creatininemia increase, marker of renal fonctionnal insufficiency, occurs only occasionally and lately.

[Value of plasma fibronectin in pediatric intensive care]. / Valeur de la fibronectine plasmatique en réanimation pédiatrique.

This work was undertaken to demonstrate the pathophysiologic and prognostic value of plasma fibronectin measurement in critically ill children. Fibronectin was measured by laser-nephelometry in 25 children (group 1) whose ages ranged from 1 month to 12 years (mean: 13.8 months). All presented with severe infections. The control group consisted of 16 children with various benign disorders, whose ages ranged from 3 months to 13 years (mean: 3.6 years). Fibronectin plasma levels in group 1 (mean: 0.16 g/l +/- 0.08) and in the control group (mean: 0.28 +/- 0.10) were significantly different (alpha less than 0.001). The initial concentration and the kinetics of this protein during evolution seem to have a good diagnostic and prognostic value in severe infections in children.

Effect of phosphate supplementation to breast fed very low birthweight infants on urinary calcium excretion, serum immunoreactive parathyroid hormone and plasma 1,25-dihydroxy-vitamin D concentration.

The effect of two doses of Phosphorus (P) supplementation to pooled breast milk (BM): 0.48 and 0.800 mmol/kg/24 h given during the second month of life was evaluated in 22 very low birthweight infants. The concentration of calcium and phosphorus in serum and urine, the serum concentration of immunoreactive parathyroid hormone (iPTH) and the plasma 1,25-dihydroxy-vitamin D concentration (1,25-OH-D) were compared to the values in 19 control infants. The mean +/- SD concentrations in control infants and adults are 63 +/- 18 microliters Eq/ml for serum iPTH and 85 +/- pmol/l for plasma 1,25-OH-D. With 0.48 P supplementation, urinary Ca (UCa) excretion (median and range) 0.238 mmol/kg/24 h (0.105-0.520) was lower than in the control group 0.288 (0.205-0.679) (p less than 0.05); the reduction of UCa was larger with 0.8 P supplementation: 0.047 (0.023-0.163) (p less than 0.01). P supplementation induced no change in serum Ca concentration but a slight and significant increase in serum iPTH was observed only with the 0.8 P supplementation: 55 microliters Eq/ml (less than 25-80) (p less than 0.05). With 0.8 P supplementation there was no significant change of plasma 1,25-OH-D concentration: 173 pmol/l (106-271) vs. 255 (132-293) in the control group. These data show that with 0.8 P supplementation, the hypercalciuria in BM-fed infant disappears without secondary hyperparathyroidism, but without any change in plasma 1,25-OH-D concentration.

[Role of a hypertonic theophylline solution and blood transfusion in necrotizing colitis]. / Rôle d'un soluté hypertonique de théophylline et de la transfusion sanguine dans l'entérocolite nécrosante.

The aim of this study was to evaluate the influence of an hyperosmolar solution of theophylline and of blood transfusion in the occurrence of necrotizing enterocolitis (NEC). By the end of 1982, theophylline previously given in alcoholic solution (osmolality greater than 4000 mosm/kg) was given in a preparation of sodium benzoate isoosmotic to the plasma; in addition, blood was irradiated for 20 minutes by X-Rays (5000 rads) before every transfusion. In the same unit of premature infants, the incidence of NEC was 6.7% in 1981-82; it decreased to 2.7% in 1983-84 (p less than 0.02). In the same periods of time, the incidence of NEC in very low birth weight infants (less than 1500 g) decreased from 18% to 4.7% (p less than 0.001) while the number of these very low birth weight infants had increased significantly. The incidence of blood transfusion prior to NEC was found in 67% of the patients. These data suggest a beneficial role of reducing the osmolality of theophylline and of X-Rays irradiation of blood before transfusion as a prophylaxis of NEC in premature infants.

[Cysteamine in the treatment of cystinosis in children. In vitro and in vivo studies]. / La cystéamine dans le traitement de la cystinose infantile. Etudes in vitro et in vivo.

The effect of cysteamine was studied in 6 children with nephropathic cystinosis. In 3 of them an in vitro study on fibroblasts was performed. The cystine content of fibroblasts was immediately diminished (about 90% of total cystine content) as soon as the concentration of cysteamine in the medium was greater than or equal to 0,1 mmole/l. In vivo, 50 to 89 mg/kg/day of cysteamine was administered for 9 to 37 months (mean 21,3). There was no adverse reaction. In all cases a dramatic decline in leukocyte cystine level was observed (in 5 cases the level was within the range seen in clinically unaffected heterozygotes). Growth was not improved. The renal function was stabilised in 3 cases. Photophobia which was present in 4 children decreased in 2 cases or disappeared in 2 cases.