[Impact of interferon alpha immunotherapy on tryptophan metabolism in patients with chronic hepatitis C. Results of a pilot studies on ten patients]. / Impact du traitement par interféron alpha sur le métabolisme du tryptophane chez des patients porteurs d'hépatite C chronique Résultats de la phase d'étude pilote sur dix patients.

INTRODUCTION: The proinflammatory cytokine interferon (IFN) alpha is commonly used in the treatment of patients with hepatitis C but its administration is often responsible for neuropsychiatric side effects (low mood, fatigue, sleep-wake disorders, irritability and weight loss). Various mechanisms have been incriminated to explain the production of depression and anxiety symptoms, among which serotonergic hypothesis is supported by a growing body of evidence. The latter posits that IFN-alpha is responsible for central serotonin (5-HT) depletion by deviating its precursor, tryptophan (TRP), to a catabolic kynurenine (KYN) pathway through induction of indoleamine 2.3 dioxygenase (IDO). The aim of the study was to examine the time variation of 5-HT blood (serum and platelet) levels and serum KYN/TRP ratio along with instauration of IFN-alpha therapy and to correlate these biological variations with mood fluctuations. METHOD: Patients. Ten patients (mean [S.D.] age 45 years [12.7], range 29-63; three males, seven females) with chronic hepatitis C eligible to receive IFN-alpha (1.5microg/kg/week Viraferon, Schering-Plough, administered subcutaneously) were recruited from the Gastroenterology department of the University hospital of Lille, France. Patients with cirrhosis, HIV or hepatitis B or D co-infection, persistent intravenous addiction, corticoid therapy or any DSM-IV axis 1 psychiatric disorder (diagnosed with MINI interview) were excluded. Patients with chronic active hepatitis C were assessed at baseline and monthly during the first semester of IFN-alpha and ribavirine bi-therapy. Measurements. The Montgomery Asberg Depression Rating Scale (MADRS) and the Hamilton Rating Scale for Anxiety (HAM-A) were used to assess depression and anxiety fluctuations. Serum and platelet serotonin levels were determined by HPLC with coulometric detection. Simultaneous quantification of TRP and KYN was determined by means of HPLC with fluorescence detection (TRP) or UV detection (KYN). Statistics. TRP, KYN concentrations and KYN/TRP ratio as well as MADRS and HAM-A measurements were performed at three time points (day 1, weeks 4 and 12) of IFN-alpha therapy. Analysis of variance used a linear model (with subject as the random factor) and correlation between measurements used an autoregressive model of order 1. For all probabilities, the level of significance was set at P<.05. RESULTS: Two patients were excluded before the first post-treatment assessment (results not shown). In the eight remaining patients, we observed significant increase of KYN/TRP ratio from baseline to early (week 4) and late (week 12) assessments (respectively, mean [S.D.] 5.57[5.24], 13.52[15.53] and 29.78[14.11], with P=.04). Similarly, significant increase in the MADRS (respectively 7.13[5.2], 12[6.9] and 16.6[8.6], with P=.03) and HAM-A (respectively 9.25[6.27], 15.1[6.95] and 18.7[6.27], with P=.02) mean scores were observed. Serum and platelet serotonin levels showed no significant variation with time. CONCLUSION: The results are consistent with the physiopathological hypothesis of an induction of IDO underlying depressive and anxiety symptoms related to IFN-alpha therapy in patients with chronic active hepatitis C. Nevertheless, this pilot study allows no firm conclusion since sample effective is weak and delay between IFN-alpha weekly injection and psychiatric and biological assessment was not controlled and thus may have biased our findings. However, these encouraging results advocate for further exploration of tryptophan metabolism for a better understanding of individual vulnerability to IFN-alpha-induced psychiatric adverse effects.

Ethnic differences in the distribution of CYP3A5 gene polymorphisms.

The genetic polymorphism affecting the CYP3A5 enzyme is responsible for interindividual and interethnic variability in the metabolism of CYP3A5 substrates. The full extent of the CYP3A5 genetic polymorphism was analysed in French Caucasian, Gabonese and Tunisian populations using a polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) strategy. In the three populations, eight, 17 and ten single nucleotide polymorphisms (SNPs), respectively, were identified, among which nine correspond to rare new mutations. Also identified were 16 alleles including eight new allelic variants. Significant differences were observed in the distribution of these alleles. Particularly, the frequency of the CYP3A5*3C null allele in French Caucasians (81.3%) and in Tunisians (80.0%) is higher than in the Gabonese population (12.5%) (p < 0.001). Considering the CYP3A5 genotypes of the tested individuals, only 10.4% of French Caucasians and 30.0% of Tunisians were identified as CYP3A5 expressors. In contrast, 90.0% of Gabonese subjects appear to express the CYP3A5 protein.

Use of acetaminophen in young subelite athletes.

AIM: The purpose of the present investigation was to look for other drugs besides doping substances in the urine of subelite athletes submitted to heavy training. METHODS: One hundred and forty-one young subelite athletes (in sprint, cycling, middle distance running and handball) were included in the study, with a control group of 89 high school pupils. Drugs were researched by high performance liquid chromatography using a diode array detector. RESULTS: Among the 212 subjects who agreed to give a urine sample, acetaminophen was detected: 9.5% for the subelite athletes versus 1.3% for the control group with a greater difference for sprint and cycling training (26.7% and 20%, respectively). Acetaminophen is used to treat both acute and chronic pains. It relieves pain by elevating the pain threshold. CONCLUSIONS: The use of acetaminophen has to be taken into account by medical staff, trainers and educators.

Simultaneous determination of tryptophan and kynurenine in serum by HPLC with UV and fluorescence detection.

Tryptophan metabolism is disturbed in mental depression, and the induction of indoleamine 2,3-dioxygenase increases kynurenine production. In order to determine this disturbance in patients with chronic hepatitis C and receiving interferon-based immunotherapy, a new and specific HPLC protocol was elaborated. For tryptophan, the assay was linear from 6.25 to 100 micromol L(-1), and the limits of detection (LOD) and quantitation (LOQ) for the method were 0.7 and 8.0 micromol L(-1). For kynurenine, the linearity of calibration was from 0.0625 to 6.25 micromol L(-1), with LOD and LOQ of 2 and 3 nmol L(-1). Reproducibility and repeatability were satisfactory. The method allowed study of human blood serum.

Determination of glyphosate in biological fluids by 1H and 31P NMR spectroscopy.

Identification of glyphosate in four cases of poisoning, using nuclear magnetic resonance spectroscopy of biological fluids is reported. It has been performed by using a combination of 1H and 31P NMR analyses. Characterization of the N-(phosphonomethyl) glycine herbicide was achieved by chemical shift considerations and coupling constant patterns: CH2-(P) presents specific resonance at 3.12 ppm and appears as a doublet with a H-P characteristic coupling constant of 12.3 Hz. Moreover, resonances due to isopropylamine were present, confirming the ingestion of the considered trade formulation. After a calibration step, quantitation was performed by 1H and 31P NMR spectroscopy. The benefit and reliability of NMR investigations of biological fluids are discussed, particularly when the clinical picture is quite confusing.

Identification and quantitation of xenobiotics by 1H NMR spectroscopy in poisoning cases.

In order to analyse a wide range of xenobiotics and their metabolites present in biological fluids, NMR spectroscopy can be used. A large variety of xenobiotics (therapeutic agents, pesticides, solvents, alcohols) can be characterized and quantitated directly, without sample preparation. NMR investigations were applied to acute poisoning cases, involving drugs such as salicylates and valproic acid (VPA). In a salicylate poisoning case, the three major metabolites of acetylsalicylic acid have been detected in crude urine, and rapid identification of lysine revealed the origin of the intoxication, namely lysine acetylsalicylate (Aspegic). Valproic acid as its glucuronide was identified in urine samples from two poisoned patients. 1H NMR was also used to identify and quantitate paraquat (Gramoxone) in urine owing to its two aromatic signals at 8.49 and 9.02 ppm, in two acutely poisoned patients (183 and 93 mg/l). An intentional poisoning case with tetrahydrofuran (THF) was also investigated. Serum and urine samples were collected. THF was characterized by its resonances at 1.90 and 3.76 ppm, and quantified at 813 and 850 mg/l in the two biological fluids, respectively. Moreover, two other compounds were detected: lactate and gamma-hydroxybutyric acid (GHB). 1H NMR spectroscopic analysis of serum samples from three poisoned patients revealed methanol in one case and ethylene glycol in the two others. Moreover, in the same spectrum, the corresponding metabolites formate and glycolate were found. Compared with the reference chromatographic or spectrophotometric methods, requiring time-consuming extraction and/or derivatization steps, NMR spectroscopy allows the determination of many exogenous and endogenous compounds, without any pre-selection of the analytes.

1H NMR spectroscopic investigation of serum and urine in a case of acute tetrahydrofuran poisoning.

This article reports the investigation by 1H nuclear magnetic resonance (1H NMR) spectroscopy of biological fluids in a case of intentional poisoning with tetrahydrofuran (THF). Occupational exposures to this solvent are well documented, but acute poisoning cases are extremely rare, and the one presented here is the second known case of this kind. Urine and serum samples were collected. Without any pretreatment, the presence of THF was confirmed by characteristic resonances at 1.90 and 3.76 ppm; high lactate levels were also observed. The presence of gamma-hydroxybutyric acid (GHB) was noted. Quantitative analysis was performed by relative integration of peak areas. THF concentrations were 813 and 850 mg/L (11.3 and 11.8 mmol/L), and GHB concentrations 239 and 2,977 mg/L (2.3 and 28.6 mmol/L) in serum and urine, respectively. A gas chromatographic-mass spectrometric method confirmed 1H NMR observations. The origin of GHB detected in serum and urine is also discussed.

Valproic acid intoxication identified by 1H and 1H-(13)C correlated NMR spectroscopy of urine samples.

Analysis of biological fluids by proton and carbon nuclear magnetic resonance spectroscopy (1H and 13C NMR) is a promising tool in clinical biology. We used this method for rapid toxicological screening in the case of two suicide attempts. For each case, a urine sample was analysed at 300 MHz by 1D and 2D sequences (TOCSY and HMBC) in a short experimental time. Quantification was performed by peak integration on the 1D 1H NMR spectrum. For the two patients, results showed the same resonances of the major metabolite, valproyl-O-glucuronide at concentrations of 121 and 44 mmol/l.

Does halothane or isoflurane affect hypoxic and post-hypoxic vascular response in rabbit aorta?

BACKGROUND: Halothane and isoflurane affect differently endothelium-dependent and -independent vasorelaxation at 95% O2. In addition, hypoxic vascular response might involve endothelium-dependent and -independent mechanisms. Therefore, we investigated, in rabbit aortic rings, 1) the influence of halothane and isoflurane on vasodilation at 95% O2 and on hypoxic-induced vasorelaxation at 0% O2 and 2) the influence of halothane and isoflurane on endothelium-dependent and -independent post-hypoxic vascular response. METHODS: Endothelium-intact and endothelium-denuded rabbit aortic rings were used. Phenylephrine precontracted rings were exposed, at 95% O2, to acetylcholine (ACh, 10(-9) to 10(-4) M) or sodium nitroprusside (SNP, 10(-9) to 10(-4) M) in the presence or absence of anaesthetic at 1 or 2 MAC. Precontracted rings were also exposed to an acute reduction in O2 from 95% to 0% followed by an acute reoxygenation with 95% O2 in the absence or presence of anaesthetic at 1 or 2 MAC. RESULTS: At 95% O2, halothane decreased endothelium-dependent relaxation to ACh, while endothelium-independent relaxation to SNP was decreased only at 2 MAC. Isoflurane did not modify ACh- or SNP-induced relaxation. At 0% O2, neither halothane nor isoflurane altered the hypoxic vascular relaxation. Post-hypoxic response was not changed either. CONCLUSION: Our results indicate that halothane and isoflurane do not alter vascular hypoxic response in conductance arteries.

Determination by 1H NMR spectroscopy of paraquat in urine from acutely poisoned patients. Comparison with second-derivative spectroscopy method.

The application of 1H nuclear magnetic resonance (NMR) spectroscopy to characterize and quantitate paraquat in urine is described. Characterization was performed taking advantage of two NMR spectroscopy parameters: chemical shifts and coupling patterns. Without any pretreatment of the biological samples, herbicide was detected by its aromatic doublets at 8.49 and 9.02 ppm. Quantitation of the xenobiotic was realized by relative integration of the dipyridyl protons to an internal standard. After a validation step using control urine samples, quantitation was performed in urine obtained from two poisoned patients. On admission, mean paraquat concentrations were 985 (patient 1) and 500 (patient 2) micromol/L. Results are compared and found to be in good agreement, using a second-derivative spectroscopy method.

[Analysis of two cases of valproic acid intoxication by 1H NMR spectroscopy and gas chromatography/mass spectrometry]. / Analyse de deux cas d'intoxication par l'acide valproïque par spectroscopie RMN 1H et CPG/SM.

Analysis of urine samples from two poisoned patients was performed using proton nuclear magnetic resonance (1H NMR) spectroscopy and a classical GC/MS protocol. Valproic acid as its glucuronide was identified and quantified in the 1H NMR spectra recorded directly from 0.5 mL of the collected samples. Moreover, a significant lactic aciduria could be observed. Comparison with the GC/MS findings suggests that 1H NMR spectroscopy can be clinically useful.

[Identification and quantification of exogenous metabolites in biological liquids with new development in NMR spectroscopy in one and two dimensions]. / Identification et quantification de métabolites exogènes dans les liquides biologiques avec les nouveaux développements de la spectroscopie RMN en 1 et 2 dimensions.

By comparison of urine 1H NMR spectrum from a healthy person with those from poisoned patient, we have displayed one or several signals related to intoxication. In complement, various 1H and 13C NMR sequences in 1 and 2 dimensions (J-resolved, TOCSY, HMBC) were used to identify xenobiotic metabolites and quantify them in urine from patients poisoned with salicylate acetyl, chloroquine, valproïc acid, ethylene glycol and pesticides. NMR techniques provide a rapid determination on a small sample volume without pretreatment.

Poisoning with methanol and ethylene glycol:1H NMR spectroscopy as an effective clinical tool for diagnosis and quantification.

Analysis of serum and urine samples from three patients in a metabolic acidotic state was performed using biochemical methods and proton nuclear magnetic resonance (1H NMR). Methanol and ethylene glycol were identified by their singlet peaks in the 1H NMR spectra recorded directly from 0.5 ml of the collected samples. Quantification of these compounds was obtained simultaneously with that of their metabolites, formate and glycolate respectively and of lactate and ethanol, the latter being used as an antidote. The NMR results were found to be very similar to the biochemical findings. The results presented here suggest that 1H NMR can be clinically useful since it quickly provides information on the onset of metabolic acidosis and on the biotransformation of xenobiotics.

1H-NMR analysis of trimethylamine in urine for the diagnosis of fish-odour syndrome.

This paper reports the use of proton NMR spectroscopy for the analysis of trimethylamine in the urine of a patient with trimethylaminuria. Analysis of this compound was also performed for other members of his family. Qualitative and quantitative determination of trimethylamine and trimethylamine-N-oxide was simultaneously performed on untreated urine within a few minutes. The application of the method is discussed.

1H NMR investigation of toxic effects of lindane and paraquat on Hep 3B and Hep G2 human hepatoma cell lines.

Lindane and paraquat induce biochemical changes in the liver. In order to specify their molecular impact at the cellular level, a 300 MHz 1H NMR investigation of hepatoma cell lines Hep 3B and Hep G2 responses was performed. Cells were exposed over 24 h to 50 mg/L lindane (0.178 mM) or to 100 mg/L (0.389 mM) paraquat concentrations. The main observation following exposure to lindane was a decrease in betaine methyl groups (3.26 ppm) which could be related to the steatosis reported by some authors. Specifically, in Hep G2 cells with this pesticide, the glycine peak (3.56 ppm) was lowered, thus confirming that the glycine synthesis pathway involving methionine, choline, and betaine was disturbed by lindane. Moreover, in this hepatoma cell line, the p-chlorobenzoate ion could be detected as a doublet at 7.55 ppm. In Hep 3B cells, paraquat increased betaine and methionine levels, suggesting disturbance in glycine biosynthesis. Possibilities of cellular uptake were considered, and the presence of this herbicide in cells was revealed by spectrophotometric and NMR measurements after chlorhydric hydrolysis, suggesting interaction with cellular components. The impact of paraquat on Hep G2 cells appeared to be located on mitochondrial function, as indicated by the observed decrease in succinate and pyruvate levels.

Diagnosis of a case of acute chloroquine poisoning using 1H NMR spectroscopy: characterisation of drug metabolites in urine.

Analysis of biological fluids by proton nuclear magnetic resonance spectroscopy (1H NMR) is a promising tool in clinical biology. We have used this method for a rapid toxicological screening in the case of a suicide attempt. A urine sample was analysed at 300 and 600 MHz by 1D and 2D sequences (J-resolved and TOCSY) in a short experimental time. Quantification was realized by peak integration of the 1D spectrum. The results showed the presence of chloroquine and its major metabolite monodesethylchloroquine at concentrations of 462 and 140 mg/L, respectively. Ethanol was also detected in the spectrum. It can be concluded that 1H NMR provides many advantages as a tool for clinical diagnosis in a case of acute intoxication.

Salicylate poisoning: two-dimensional J-resolved NMR urinalysis.

Identification of a case of acute salicylate intoxication using 300 MHz 1H NMR spectroscopy of a urine sample is reported. It has been achieved by using a combination of a one-dimensional experiment with water presaturation and a two-dimensional homonuclear J-resolved experiment. By these means, lysine and the three major metabolites of acetylsalicylic acid have been assigned in the crude urine. The results are compared with those obtained at 600 MHz and with classical biochemical methods. The use of this method for routine diagnosis in biological analysis is discussed.

Halothane and isoflurane decrease calcium sensitivity and maximal force in human skinned cardiac fibers.

BACKGROUND: Reports of the direct effects of volatile anesthetics on cardiac myofibrils, studied in various mammalian species but not in humans, have conflicted. To determine whether volatile anesthetics directly affect cardiac contractile proteins in humans, we examined the effects of various equianesthetic doses of halothane (0.46, 0.83, and 1.23 mM, equivalent to 0.75, 1.50, and 2.25%, respectively) and isoflurane (0.63, 1.22, and 1.93 mM, equivalent to 1.15, 2.30, and 3.50%, respectively) on the Ca2+ sensitivity and maximal force in human skinned cardiac fibers. METHODS: Left ventricular muscle strips were obtained from seven patients undergoing cardiac surgery. Sarcolemma was disrupted with EGTA (ethylene glycol bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid), and sarcoplasmic reticulum was destroyed with EGTA plus BRIJ 58 detergent. Ca2+ sensitivity was studied by observing the isometric tension developed by skinned fiber bundles challenged with solutions of increasing Ca2+ concentrations expressed in pCa (where pCa = -log10[Ca2+]). Maximal force was measured with a pCa 4.8 solution. RESULTS: Both anesthetics shifted the pCa-tension curves toward higher Ca2+ concentrations and decreased pCa for half-maximal activation in a dose-dependent and reversible fashion (from 5.71 for control to 5.56 and 5.55 for 1 MAC halothane and isoflurane, respectively) without changing the slope of this relationship (Hill coefficient). No differences between agents were observed at equianesthetic concentrations. The two agents also decreased the maximal activated tension in a dose-dependent fashion (-27 and -28% vs. control for 2 MAC halothane and isoflurane, respectively). CONCLUSIONS: The current study indicates that halothane and isoflurane decrease Ca2+ sensitivity and maximal force in human skinned cardiac fibers at 20 degrees C. If these effects extend to higher temperatures, they may contribute to the negative inotropic effect of these agents.