[Multicenter evaluation of h-FABP semi-quantitative assay (Cardio Detect) in central laboratory: the point in acute myocardial infarction diagnosis]. / Evaluation multicentrique du dosage semi-quantitatif de la h-FABP (Cardio Detect) au laboratoire central : intérêt dans le diagnostic de l'infarctus du myocarde.

The diagnostic performance of heart-Fatty Acid Binding Protein (h-FABP) (semi-quantitative CardioDetect test) and cardiac troponin I (TnIc) blood assays were compared in one hundred patients presenting with suspicion of acute coronary syndrome. Final patient diagnosis was "acute myocardial infarction" in 36 cases, "non ST myocardial infarction" in 25 cases and "non ischemic pathologies" in 39 cases. h-FABP results were positive in 26 patients, negative in 57 patients and ambiguous in 17 patients, the latter corresponding to the final diagnosis of "acute myocardial infarction" in 5 cases, "non ST myocardial infarction" in 2 cases and "non ischemic pathologies " in 10 cases. At admission, h-FABP and TnIc exhibiteda sensitivity of 54% an 66%, respectively and a specificity of 86% and 95%, respectively. Positive and negative predictive values were 81% and 64% for h-FABP, respectively and 92% and 75% for cTnI, respectively. h-FABP and cTnI demonstrated a similar diagnostic efficiency if admission delay is less than 4 hours after onset of chest pain (area under ROC curve TnIc = 0.767 +/- 0.091 ; area under ROC curve h-FABP = 0.622 +/- 0.109 ; p = 0.144). On the contrary, cTnI assay demonstrated a better efficiency than h-FABP (p< 0.005) for patients admitted in a delay of 4 to 12 hours after the onset of chest pain. If chosen cTnI cut-off corresponded to the recent consensus definition used for monitoring acute coronary syndrome patients, h-FABP semi-quantitative assay realized within central laboratory did not demonstrated a better diagnostic efficiency than cTnI.

[Multisite validation of CDT measurement by the %CDT TIA and the Tina Quant %CDT kits]. / Validation multicentrique du dosage de la CDT par les méthodes %CDT TIA et Tina Quant %CDT.

The measurement of CDT (Carbohydrate Deficient Transferrin) is an essential biological tool in the diagnosis and follow-up of alcohol abuse. It is also employed as a marker of abstinence for the restitution of driving licences. However, the precision of measurement, and the between laboratory homogeneity of the results are still discussed. The ion exchange followed by immunodetermination of CDT is available in two products, the Tina Quant %CDT (Roche, Mannheim, Germany) and the %CDT TIA (Bio-Rad, Hercules, United States). This multicentre study was undertaken: 1) to evaluate the analytical characteristics of these kits and the homogeneity of the results from one laboratory to another, independently of the method used, 2) to validate the differences between the proposed normal values of both kits, 3) to study the possibility of using commercial control sera as external quality control. Four analytical systems were included in the study (Roche Modular/Hitachi 717, Beckman Coulter Immage and LX20, Dade Behring BNII). Determinations were carried out on pools of sera, commercial control sera, kit controls, and 30 serums of patients. These latter were also analyzed in capillary electrophoresis in order to establish correlations between the techniques. The calibrations were stable over one 2 weeks period. The repeatability of measurements spread out from 3,1% to 24,7%, for a mean value lower than 10%. The commercial control sera provided reliable results, with values adapted to a routine quality control use. The results of the Bio-Rad applications were lower by approximately 20% than those of the Roche application, which justifies the difference of the normal values (2,6% versus 3%), and an identical classification of the patients in at least 27 of the 30 samples. We conclude that the analytical quality of the compared techniques, even if it could be improved, is sufficient to guarantee a good reliability of the results. An external quality control could be proposed by using the control sera that we tested.

[Prescription, assay and interpretation of cardiac troponins tests: guidelines from SFBC-CNBC troponin working group]. / Recommandations sur la prescription, le dosage et l'interprétation des troponines cardiaques.

Troponin (I or T) has become the gold-standard marker in acute coronary syndromes during the last few years, as confirmed by a national survey realized within french clinical chemists, cardiologists and emergency practitioners. The importance of this marker and the heterogeneousness of circulating forms of troponin after myocardial necrosis fully justify international studies about standardization of this assay, which is a central bulk to reach a global market coherence. Checking analytical problems, although necessary, must be absolutely associated with an informed clinical interpretation. The knowledge of the crucial thresholds of each assay, the kinetic curves and the specificity limits of troponin assays allow the best use of their potential in diagnosis and prognosis together with an optimal patient care in very different clinical settings, in addition to others clinical and technical arguments. The quality improvement through successive generations of assay kits must nowadays persuade the physicians never to ignore a significant and valid troponin increase, which mainly reveals a cardiac injury, whatever its origin.

[Measurement of urinary free cotinine. Comparison with the level of expired air carbon monoxide]. / Dosage de la cotinine urinaire libre. Deuxième partie: comparaison avec le taux de monoxyde de carbone dans l'air expiré.

BACKGROUND AND AIM: Cotinine is a very reliable index for the estimation of active or passive smoking. Sampling from a single urine void is well accepted by smokers who are willing to stop. It is not possible to exclude modification of urine cotinine according to beverage intake. The aim of this study was to determine if urine cotinine concentration must necessarily be adjusted to creatinine or not, by making comparison with expired air carbon monoxide. MATERIAL AND METHODS: Carbon monoxide was measured in 53 smokers coming for the first time in a smoking cessation program. Urine cotinine was measured by HPLC-UV. The cut-off value for abstinence is 8ppm and 0.05 mg/L, repectively. Urine creatinine was determined using the Jaffe reaction. RESULTS: Mean CO level was 18.5 +/- 10.6 ppm and mean urine cotine was 1.45 +/- 0.86 mg/L. Eight smokers had CO 8 ppm. They should be considered as abstinent. However, only one of them had a cotinine under the detection limit. Urine creatinine varied in a large range (0.7 - 35 mmol/L). But, cotinine was only weakly correlated to creatinine (r = 0.279, p = 0.037). There was a highly significant correlation between cotinine and CO (0.649, p = 0.0001). The correlation of cotinine/creatinine versus CO was not significant (r = 0.249, p = 0.072). In order to take into account fluid intake, urine cotinine of each sample was adjusted as if creatinine was equal to the mean (8.3 mmol/L) of the group of subjects. The correlation observed with adjusted or non adjusted cotinine and CO (r = 0.640, p < 0.0001) was the same. CONCLUSION: Urine cotinine from a single void is an accurate index of tobacco smoking at the individual level. There is no need to adjust cotinine concentration, taking into account urine creatinine. Measurement of urine cotinine can be useful to manage smokers who deliberately wish to overcome tobacco dependence, offering the opportunity to provide an adequate level of nicotine substitutive therapy. It is also of peculiar importance to follow-up pregnant women and smokers for whom cessation is required after a clinical event. Finally, absence of cotinine in urine can be used to document abstinence from tobacco products.

[Urinary cotinine and nicotine metabolites measurement]. / Dosage urinaire de la cotinine et des métabolites de la nicotine.

UNLABELLED: According to the recent regulations (Circulaire DGS/DH du 3 avril 2000), tobacco dependence must be determined by the measurement of urine nicotine metabolites. Various assay methods are presently available. They were tested in order to evaluate their analytical performances and to determine how they can be used for the clinical management of smoking cessation. MATERIAL AND METHODS: Urine samples from a single void (n = 97) were obtained from active and abstinent smokers (with or without nicotine substitutive therapy). They were all analyzed by the various methods. Cotinine concentration was measured in six laboratories, using HPLC combined with UV detection according to a standardized procedure (Ann Biol Clin 2002 : 60 : 263-72). Immunoassay methods were also tested and the values obtained from urine samples were compared to urine cotinine measured by HPLC-UV. RESULTS: HPLC-UV: Urinary cotinine varied in a range from undetectable to 4 mg/L. An interlaboratory comparison was performed according to the Valtec procedure (calculation of equation of Deming, chart of differences). There was a good accordance between laboratories. Cotinine concentration was only slightly influenced by fluid intake, as shown by a poorly significant correlation between cotinine and creatinine (r = 0.23, p = 0.05). Homogeneous immunoassays: The two homogeneous immunoassays (Cotinine) from Thermo Electron and Cotinine Enzyme Immunoassay commercialized by Microgenics were highly correlated (r = 0.97). The correlation was not so strong with HPLC-UV (r = 0.86). Firstly, values were found higher with immunoassays because antibodies crossreact with 3-hydroxycotinine. Secondly, the ratio of immunoassays values to HPLC-UV values varied according to urine specimens. Finally, there was a highly significant correlation with urine creatinine (r = 0.40, p = 0.0001), thus indicating the influence of fluid intake. Heterogeneous immunoassay: The kit Metabolites of Nicotine commercialized by DPC France was tested on the analyzer Immulite, using a procedure specifically established for urine. Antibodies revealed a large spectrum of nicotine metabolites. Therefore, the values were much higher than those observed for the same urine samples with homogeneous immunoassays. CONCLUSION: HPLC-UV can be recommended for the measurement of urinary cotinine, as it was shown a good accordance between laboratories. The low detection limit is of interest for the diagnosis of Environmental Tobacco Smoking. Homogeneous immunoassays can be easily used for routine analysis as they can be performed directly on urine specimen. The results must be interpreted according to cut-off values specifically established according to homogeneous or heterogeneous immunoassays. Variability induced by fluid intake must be taken into account. The interest of the heterogeneous immunoassay needs to be confirmed for the diagnosis of Environmental Tobacco Smoking.

Effects of postnatal aluminum exposure on biological parameters in the rat plasma.

Young rats were treated by gastric intubation with aluminum chloride (100 mg Al/kg/day) and aluminum lactate (100 and 200 mg Al/kg/day) from postnatal days 5 to 14. This treatment lead to a reduction in body weight. The plasma concentrations of total proteins and albumin decreased whereas the alpha 1 globulins increased in the treated rats. The aluminum concentrations in plasma and hepatic homogenates increased particularly at 200 mg Al lactate. The reduction in average body weight could be attributed to various causes: a decreased food consumption, a transient undernutrition, a reduction of the protein synthesis in the liver. The increase of the plasma concentration of the alpha 1 globulins revealed an inflammation process.

Effects of fluoxetine and norfluoxetine on 5-hydroxytryptamine metabolism in blood platelets and brain after administration to rats.

The effects of intraperitoneal administration of fluoxetine (2.5, 5, 10 or 20 mg kg(-1)) and norfluoxetine (10 mg kg(-1)) on 5-hydroxytryptamine (5-HT) and 5-hydroxyindole-3-acetic acid (5-HIAA) metabolism were examined in the blood platelets and brain of rats killed 3 h after a single dose. Several experiments were performed to evaluate the effect of norfluoxetine. Plasma 5-HT concentrations decreased significantly (48%) compared with control group results 3 h after administration of a single dose of fluoxetine (10 or 20 mg kg(-1)). Similar plasma 5-HT levels, 0.54+/-0.04 and 0.56+/-0.09 mg L(-1), respectively, were observed after administration of 10 mg kg(-1) fluoxetine or norfluoxetine. In the same way 5-HIAA levels in whole brain were similar, 0.36+/-0.03 and 0.34+/-0.01 microg(-1), respectively, after administration of fluoxetine or norfluoxetine. There was a good correlation between plasma and brain levels of fluoxetine (0.962) and norfluoxetine (0.957). The results suggest that fluoxetine and norfluoxetine lead to reduced levels of 5-HT in platelets and of 5-HIAA in the brain. Like the parent drug, norfluoxetine is a potent and selective inhibitor of 5-HT uptake.

Effects of aluminum chloride on normal and uremic adult male rats. Tissue distribution, brain choline acetyltransferase activity, and some biological variables.

Normal and uremic adult male rats were given a daily ip injection of 20 mg Al (Al chloride)/kg for 14 d. The results indicate that Al induces a significant decrease in food ingestion, weight gain, and total protein concentration in the plasma. Compared with control animals, very high increases in Al levels were found in plasma and hepatic homogenates (about 36 and 19 times, respectively). In the brain homogenates, the Al increases were lower (about 23%). The brain cholineacetyltransferase activity was reduced: 10.6 and 14.9% in normal and uremic rats, respectively. The nephrectomy and the food restriction did not affect the total protein concentrations in plasma and the cerebral cholineacetyltransferase activity. Both were only found to be reduced in the rats treated by Al chloride.

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.

[Comparison of methods for the determination of blood creatinine]. / Comparison des méthodes de dosage de la créatinine sérique.

Creatinine is the criterion the most widely used for kidney exploration, either directly or through algorithms. Up to now, it appears that methods of creatinine determination are still very heterogenous. The aim of the present study was to compare the different available methods and to evaluate their impact on the formula of predicted clearance. The study revealed that significant discrepancies can be observed depending on the methodology and analitycal principe. The results suggest that standardization of methods and comprehensive analysis of the different formula are necessary.

[Biomarkers for toxicity and metabolic abnormalities of the main severe poisonings. Clinical and toxicologic symptoms. Conservative determination]. / Biomarqueurs de toxicité et anomalies métaboliques dans les principales intoxications graves. Symptomatologie clinique et toxique. Le prélèvement conservatoire.

The members of the joint group "Toxicology and Clinical Biology" of the French Society of Clinical Biology (SFBC), the French Society of Analytical Toxicology (SFTA), and the Society of Clinical Toxicology (STC), suggest guidelines to meet the requirements of clinical biologists who are not specialized in toxicology. Based on good laboratory practice they propose a number of guidelines. Three synthetic tables have been established. They are not only toxicity biomarkers and metabolic disorders associated with the main severe intoxications, but also clinical signs that are observed during these intoxications, finally biological sampling as a precautionary measure. The table also takes into account approximately fifty xenobiotics: main clinical signs emergency, identification or quantification of the suspected product, useful biological markers, therapeutic, quantitations necessary to take into consideration patient care, and poison antidotes, are described. Recommendations regarding medical and forensic techniques are also proposed by the group. It is also necessary to collect and store biological samples when the individual patients are in charge. These samples will be analyzed or not depending on the individual case history.

[Biomarkers of tobacco smoke exposure]. / Les marqueurs spécifiques du tabagisme.

Tobacco smoking is a major risk factor for cancer, cardiovascular diseases and respiratory illnesses. Smoking is increasing among children and adolescents with subsequent consequences on the health. Furthermore, maternal tobacco smoking during pregnancy adversely affects prenatal growth. Nicotine, the most important tobacco alkaloid, is responsible for maintaining tobacco addiction. According to a recent Circulaire de la direction générale de la santé, nicotine dependence should be determined through questionnaires and quantitative estimate of nicotine metabolites. Nicotine blood level fluctuates and urinary nicotine excretion is of short duration. Nicotine is intensively metabolized in the liver and oxidized into cotinine. Urinary measurement of cotinine appears to be highly related with the degree of intoxication and to allow the differentiation between non exposed and exposed non-smokers. In order to check the present application of nicotine metabolites measurement, a survey was conducted in 340 smoking cessation units. Forty percent physicians (n = 137) answered the survey. For 17% of them, the quantification of nicotine metabolites is included in their daily practise and for 79%, guidelines about cotinine measurement should be given in France. Sixty-seven biologists answered the survey. Recommendations for immunoassay and HPLC determination of cotinine should be given as reported by 66 and 44% of them respectively. Indeed, urinary cotinine measurement with high performance liquid chromatography is highly sensitive and specific. However, immunoassays are more convenient. These two approaches are presently under investigation in order to provide guidelines for optimal use in various clinical situations. Traditional measures for nicotine dependence are the number of cigarettes smoked per day, nicotine intake expressed as mg per day, Fagerstr m questionnaire, expired air carbon monoxide, thiocyanates and cotinine levels in biological fluids. Urinary cotinine measurement is the most useful for the follow-up of smoking cessation including adjustment of nicotine replacement therapy, especially after a clinical event or for the follow-up of smoking pregnant women. It allows the detection of passive smoke exposure in children who are hospitalized for recurrent respiratory illnesses.

[Effect of fluoxetine treatment on serotonin and MHPG in 32 patients with major depressive disorder]. / Effet d'un traitement à la fluoxétine sur la sérotonine et le MHPG chez 32 patients atteints de dépression majeure.

Considering the concept that depressive disorders were not only resulting from activity of one neurotransmitter, possible interactions between the noradrenergic system and a selective serotonin uptake inhibitor, fluoxetine, were investigated in order to test the hypothesis of noradrenergic or serotonergic involvement in depression. So the biological parameters (plasma and urinary MHPG, platelet serotonin) were evaluated by HPLC. The aim of this study was to evaluate the correlations between the concentrations of MHPG and serotonin in 32 melancholic patients treated by fluoxetine (20 mg/day) during a minimum of three weeks. The clinical examination with evaluation of the antidepressant effect carried out using the HDS/MES rating scale, allowed to divide the patients into three groups: responders to treatment, partial responders and non responders. In the same time, a control group of healthy subjects was investigated. ANOVA applied to platelet serotonin at day 0 showed a tendency toward heterogeneity between the three patient groups and the control group. The concentrations of serotonin in the three patients groups were highly reduced after 21 days of treatment. Concerning plasma and urinary MHPG there was non significant difference among the three patients groups at day 0 and the control groups. After treatment by fluoxetine, the results suggest that the urinary sulfate MHPG is an indicator of the metabolism of brain norepinephrine and seems to be a better turnover indicator than the plasma sulfate MHPG. The selective evaluation of sulfate and glucuronide MHPG could give a better survey of the psychobiological state of the patients than the total MHPG evaluation.

[Fluoxetine: relations between plasma concentration and therapeutic effects in 32 patients with major depression and treated with 20 mg/day]. / Fluoxétine: relations entre concentrations plasmatiques et effets thérapeutiques chez 32 patients atteints de dépression majeure et traités à 20 mg/j.

The aim of this clinical study was to investigate 32 melancholic patients treated by fluoxetine (20 mg/day). The clinical examination to evaluate the antidepressant effect of fluoxetine was realized by using the HDS/MES criteria. The patients were divided into three groups (responders, partial responders with or without a relapse, non responders) according to their clinical evolution during treatment. Fluoxetine and norfluoxetine were evaluated by HPLC after 3 weeks of treatment. In the present study, 53% of the patients have a positively reaction to the 21 day's treatment. Our results showed no correlation between the psychiatric scores and the plasma concentrations of fluoxetine and norfluoxetine.

Automated separation for heterogeneous immunoassays.

Beside general requirements for modern automated systems, immunoassay automation involves specific requirements as a separation step for heterogeneous immunoassays. Systems are designed according to the solid phase selected: dedicated or open robots for coated tubes and wells, systems nearly similar to chemistry analysers in the case of magnetic particles, and a completely original design for those using porous and film materials.

Assay of urinary free and conjugated 3-methoxy-4-hydroxyphenylethyleneglycol by high-performance liquid chromatography with amperometric detection.

The aim of this study was to develop an analytical method for free and conjugated 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) in urine. After hydrolysis of the conjugated forms, the urinary MHPG was purified by solid-phase extraction on anion exchanger and eluted with a water-methanol (1:1, v/v) mixture. After addition of ethyl acetate to the eluate and back-extraction into acetic acid, the aqueous phase was separated on a C18 column by HPLC and detected amperometrically. The results obtained from forty healthy human subjects were compared with the literature values. The precision and accuracy of the assay were studied using 4-methoxy-3-hydroxyphenylethyleneglycol (iso-MHPG) as internal standard.

[Passive smoking in children. Its detection by the assay of urinary cotinine]. / Le tabagisme passif de l'enfant. Son dépistage par le dosage de la cotinine urinaire.

BACKGROUND: Passive tobacco smoking is responsible for increased respiratory morbidity in young children. This point is not always understood by parents and the use of a sensitive marker for nicotine exposure may help them to smoke less. POPULATION AND METHODS: Urinary cotinine concentration was measured in 72 children, aged from 1 to 5 years, that had been admitted to our unit during October and November 1991 for various causes. The results were correlated with the smoking habits of their parents. Urine samples were obtained during the first hours after admission and the cotinine concentration was measured by HPLC. Concentrations > 5 micrograms per liter were considered to be positive. RESULTS: A total of 67 urine samples were analysed: 43 (64.2%) were positive with cotinine concentrations of 5 to 77 micrograms/l (mean: 19.7). Both parents of 21 children were smokers; the fathers of 18 children and the mothers of 11 children, alone, smoked. There was therefore at least one smoker in the environment of 50 children. There was a highly positive correlation between parental smoking and urinary cotinine (p < 0.0001). For the infants with only one parent who was a smoker, their urinary cotinine was higher when the smoker was the mother rather than the father. CONCLUSIONS: An urinary cotinine of > 6 micrograms per liter is a precise, sensitive, test for passive smoking in young children. This test is well accepted by families and its result may persuade parents to stop or moderate their use of tobacco. This test also could be used, as part of a pulmonary check-up, as a public health indicator.

Assessment of recently developed blood gas analysers: a multicentre evaluation.

Providing guidelines for testing expected inaccuracy and imprecision is still a matter under debate. The Expert Panel of the French Society of Clinical Chemistry has developed a protocol, which was based on a comparative multi-centre evaluation of four instruments: the Ciba-Corning 278, the Instrumentation Laboratory 1306, the Nova SP 5 and the ABL 330. The purpose was to evaluate the analytical performance and efficiency of the analysers. Another aim was to design a valid approach for evaluating any new system. As buffered aqueous solutions and fluorocarbon emulsions give only partial information, tonometered blood was used at different levels of gas mixture, even though it is both difficult and time-consuming. Comparisons have been established on patients' blood samples with the analysers currently used in the evaluation sites. The tests showed that the four analysers have the same degree of precision, and interinstrument comparisons demonstrated a very high degree of reliability.This analysis emphasizes that the evaluation of instruments for pH and blood gas analysis is neither easy nor is it often done, mainly due to the choice of a quality-control material and the lability of the measured parameters.