Inhalation of toluene diisocyanate affects cytochrome P450 2B1 expression in rat lung.

In the lung the expression of xenobiotic-metabolizing enzymes such as cytochromes P450 (CYP) and glutathione S-transferases (GST) may be affected by inhaled pollutants. Toluene diisocyanate (TDI) is a highly volatile chemical compound known to induce a wide array of diseases in workers exposed to vapors or sprays, including respiratory allergy and asthma. We investigated the effect of inhaled TDI on expression of CYP 1A1, 2B1, 2E1, and 3A1 and of alpha-, mu-, and pi-GST in rat lung. Animals were exposed to targeted concentrations of 0.01, 0.1, or 1 ppm TDI vapors or to cleaned filtered air for 8 h. Expression of CYP and GST was analyzed 18 24 h after the end of exposure using western blotting, northern blotting, and immunohistochemistry. Constitutive levels of CYP 2B1 and 3A1 proteins were found in lung tissue from control rats, whereas CYP 1A1 and 2E1 proteins were not detectable. Animal exposure to TDI vapors neither modified CYP 3A1 protein expression, nor led to any detectable expression of CYP 1A1 or 2E1. In contrast, exposure to 1 ppm TDI induced a 40% reduction in CYP 2B1 protein levels. This decrease was associated with a 33% decrease in CYP 2B1 mRNA levels. Additionally, CYP 2B1 immunolabeling localized to ciliated epithelial cells, Clara cells, and type II alveolar cells in the lung tissue of control rats was markedly decreased in animals exposed to 1 ppm TDI. Constitutive levels of alpha-, mu-, and pi-GST proteins were found in lung tissue from control rats. Exposure to TDI had no effect on lung expression of either of the GST. In conclusion, this study clearly shows a selective decrease in CYP 2B1 expression by TDI vapors in rat lung. The contribution of CYP 2B1 to metabolize further xenobiotics is therefore altered.

Effect of toluene diisocyanate and its corresponding amines on viability and growth of human lung fibroblasts in culture.

Toluene diisocyanate (TDI) is a highly volatile chemical known to cause occupational asthma in exposed workers. TDI-induced asthma is associated with airway epithelium injury and repair, and subepithelial fibrosis. We investigated the effect of TDI and its hydrolysis products, the 2,4- and 2,6-toluenediamines (TDA), on viability and growth of human lung fibroblasts (HLFs) in culture, using a tetrazolium-based cell viability assay. The effects of increasing concentrations of each of these chemicals were evaluated on quiescent cells seeded at two densities (2500 and 5000 cells/well) and treated for 24 or 48 h. TDI (10(-4)-10(-5) mol/L, as a mixture of 80% 2,4-TDI and 20% 2,6-TDI) exhibited a partial but significant cytotoxic effect (10-24%, p<0.05) on HLFs. This effect was observed at both cell densities, and was time- and concentration-dependent. 2,4-TDA, at lower concentrations (10(-8)-10(-6) mol/L) applied for 48 h, also partially reduced HLF viability (10-15%, p<0.05), whereas it tended to trigger cell growth at concentrations higher than 10(-5) mol/L. 2,6-TDA exhibited both a cytotoxic and a proliferative effect on HLFs that depended on concentration, time of exposure and cell culture density. Significant cytotoxicity was only observed after 24 h of treatment with 10(-7)-10(-6) mol/L 2,6-TDA, and reached greater intensity in cells cultured at the highest density. In contrast, 2,6-TDA stimulated HLF growth only after 48 h of incubation at 10(-4) mol/L on cells cultured at the lowest density. Taken together, our results showed that TDI and 2,4-TDA somewhat decreased HLF viability, whereas 2,6-TDA appeared to exhibit both a cytotoxic and a growth stimulatory effect on these cells. TDI and 2,4-TDA are thus suggested to contribute to airway epithelium damage associated with TDI-induced asthma, whereas 2,6-TDA might either trigger epithelial damage or induce cell proliferation that could contribute to epithelium repair or subepithelial fibrosis.

Induction of nitric oxide synthase by chlorinated pesticides (p,p'-DDT, chlordane, endosulfan) in rat liver.

The aim of this study is to investigate the effect of certain polychlorinated pesticides on the induction of rat liver Ca(2+)-independent nitric oxide synthase (NOS) and compare it with the effect of bacterial lipopolysaccharide. Our results show that endosulfan and p, p'-DDT treatment significantly increases the NOS activity while no significant induction by any route of administration was observed in the case of chlordane. Our results show therefore that a wide variety of chlorinated pesticides, which are considered as hepatic tumor promotors, can stimulate the expression of NO synthase in vivo.

Study of mercury content in edible mushrooms.

The influence of time and temperature of mineralisation of mushrooms was studied for mercury determination by cold vapor atomic absorption. Optimal conditions for a complete mercury recuperation were obtained using a mixture of nitric and sulphuric acid (6 ml HNO3, 4 ml H2SO4) in presence of KMnO4 (3 ml of a 0.44 M solution) at 95 degrees C for 4 h, with 1 g wet sample. The detection limit of method was 3.2 ng/g. These conditions have shown high reproductibility and accuracy.

Rapid method for analysis of chloroacetanilide and chloronitrophenoxyaniline herbicides by gas chromatography.

The herbicides Alachlor and Alclonifen are recently used in France for pre-emergent weed control in corn, essentially in association. For this reason, an improved method has been developed by gas chromatography for simultaneously characterising and quantifying the two herbicides. The best conditions were obtained by using a gas chromatograph equipped with an ion trap detector, and a 30 m x 0.25 mm DB-1701 fused silica capillary column. Retention times of Alachlor and Aclonifen were 12.8 and 23.2 min respectively. The limit of detection was of 2.0 ppb for each herbicide.

Determination of total mercury in estuary, lake and river sediments.

In order to improve the quality of the results in sediment analysis, the Community Bureau of Reference (BCR) of the European Communities has developed 3 sediment reference materials (CRM) from estuarine, lake and river origins. Certification of mercury content in these materials was achieved by 3 methods (cold vapor atomic absorption spectrometry, plasma emission spectrometry, neutron activation analysis with radiochemical separation). The values finally certified in the CRM estuarine, lake and river sediments are 1.77 +/- 0.06, 0.67 +/- 0.02, 1.03 +/- 0.13 mg/kg respectively.

Kinetics of nitric oxide synthase induction by Propionibacterium avidum and lipopolysaccharide.

Conditions for the induction of rat liver Ca2(+)-independent nitric oxide synthase were determined with killed Propionibacterium avidum, and compared with lipopolysaccharide endotoxin. Similar maximal induction was obtained intraperitoneally with the two types of inducers but killed Propionibacterium avidum gave a long-lasting induction while lipopolysaccharide displayed a rapid and short response. Moreover, the induction resulting from an intravenous administration of killed Propionibacterium avidum reached 60 times that of the control whereas lipopolysaccharide treatment induced a 24-fold stimulation only. It is noteworthy that with the first inducer the nitric oxide activity was stable with time whereas with the second one it dropped after 8 h. Whatever the route of administration of killed Propionibacterium avidum, some huge vacuolated Kupffer cells were found in the liver whose parenchyma was almost normal. Numerous monocytes, and unaltered Kupffer cells, were observed. Kupffer cells were identified to be responsible for the uptake of killed Propionibacterium avidum.

Simultaneous HPLC analysis of the hypnotic benzodiazepines nitrazepam, estazolam, flunitrazepam, and triazolam in plasma.

A new analytical methodology was developed for simultaneous high-performance liquid chromatographic quantitation of nitrazepam, estazolam, flunitrazepam, and triazolam in plasma. After addition of the internal standard nor-prazepam, biological samples and calibration standards were extracted at basic pH into diethyl ether-methylene chloride (2:1, v/v). The reconstituted extract was separated on a reversed-phase Nova Pak C18 column with acidic buffer (6mM)-acetonitrile-methanol (64:23:13, v/v) as mobile phase. The detection was performed at 242 nm. Within-run and day-to-day precision values were about 2-8%. The method is thus sensitive and reproducible for use in clinical and experimental toxicokinetic studies.

Determination of dextromoramide by capillary gas chromatography and electron impact mass spectrometry.

A sensitive and specific quantitative assay for the determination of dextromoramide in human fluids and tissues is described. Dextromoramide and an internal standard, SKF 525 A, are isolated by a basic extraction and back-extraction process. The final extract is separated on a 25-m capillary column B.P. 1 and drugs are detected by selected ion monitoring at m/z 100 and m/z 86 for dextromoramide and the internal standard, respectively. The minimum detectable quantities are 0.5 and 0.3 ng/mL, for dextromoramide in plasma and urine, respectively. Coefficients of variation for within-run data were less than 6%.

Toxicological findings after fatal amitriptyline self-poisoning.

A case of fatal self-poisoning with amitriptyline is reported. Both the drug and its metabolite nortriptyline were quantified in several post-mortem tissues and fluids, including vitreous humor. Results are discussed in the light of the existing literature.

[The determination of ketamine in biological fluids]. / Dosage de la kétamine dans les liquides biologiques.

A method for the identification and quantification of ketamine in biological fluids by GC/NPD is presented. The procedure employs SKF 525 A as the internal standard and requires no derivatization. After a single-step extraction, analysis is achieved in 5 min. The lower limit of detection was found to be 1 microgram/1 for ketamine in plasma. This method appears to be rapid, sensitive and applicable to forensic and clinical toxicological analyses.

Simultaneous screening and quantification of several nonopiate narcotic analgesics and phencyclidine in human plasma using capillary gas chromatography.

This paper describes a procedure for the quantitative determination of alfentanil, dextromoramide, fentanyl, methadone, pentazocine, pethidine, phenoperidine and phencyclidine in human plasma. Some drug metabolites were included in the study. The procedure involves a simple alkaline extraction technique and capillary gas chromatography separation followed by a nitrogen-selective detection. Concentrations as low as 10 micrograms/l can be routinely evaluated, making this method suitable for use in overdose drug screening, therapeutic drug monitoring and pharmacokinetic studies.

Simultaneous determination of dextropropoxyphene, norpropoxyphene and methaqualone in plasma by gas chromatography with selective nitrogen detection.

A method for the identification and quantification of dextropropoxyphene, norpropoxyphene, and methaqualone in plasma by GC/NPD is presented. The procedure employs cyclizine as the internal standard and requires no derivatization. After a single-step extraction, analysis is achieved in 8 min. The lower limits of detection were found to be 6, 12, and 1 ng/ml for dextropropoxyphene, norpropoxyphene, and methaqualone, respectively. This method appears to be rapid, sensitive, and applicable to forensic and clinical toxicological analyses.

Fly larvae and their relevance in forensic toxicology.

Toxicological analyses on a putrefied cadaver are sometimes difficult to perform because of the absence of blood and urine. In this study, fly larvae, being living material, are proposed as a new medium of investigation in forensic toxicology. Bromazepam and levomepromazine were identified and assayed in the remains of cerebral tissue, in the clavicle of a putrefied cadaver, and in the fly larvae found on and in the corpse.

A rapid and sensitive gas chromatographic analysis of methadone and its primary metabolite.

A method for identification and quantification of methadone and its primary metabolite (1,5-dimethyl-3,3-diphenyl-2-2-ethylidene pyrrolidine) in plasma by GC/NPD is presented. The procedure employs SKF 525 A as the internal standard and requires no derivatization. After a single-step extraction, analysis is achieved in 10 min. The limit of detection was found to be 2 an 3 ng/ml for methadone and its metabolite, respectively. This method appears to be rapid, sensitive and applicable to forensic and clinical toxicological analyses.

Fly larvae: a new toxicological method of investigation in forensic medicine.

Toxicological analyses on a putrefied cadaver are sometimes difficult to achieve because of the absence of blood and urine. In this study, maggots, living material, are proposed as a new medium of investigation in forensic medicine. Five drugs (triazolam, oxazepam, phenobarbital, alimemazine, and clomipramine) were identified and assayed in some tissues of a putrefied cadaver and in the maggots found on and in the body.

Tissue distribution of dextromoramide in the rat.

The tissue distribution of dextromoramide was studied in rats after the intraperitoneal injection of 0.2 mg/kg of the drug. The pattern of distribution was similar at 15, 30, 60 and 90 min, with the highest concentrations being found in the liver and the myocardium, while other organs were not able to concentrate dextromoramide.

Simultaneous determination of pethidine (meperidine), phenoperidine, and norpethidine (normeperidine), their common metabolite, by gas chromatography with selective nitrogen detection.

This article describes a selective gas chromatographic method for the resolution and quantification of phenoperidine and its two metabolites, pethidine (meperidine) and norpethidine (normeperidine). Drugs and SKF 525 A, the internal standard, are separated from plasma by solvent extraction under alkaline conditions. They are chromatographed on a 3% OV-17 Chromosorb Q glass column and detected with a nitrogen-phosphorous detector. Linearity is observed in the study range (5-200 ng/ml). No interference by endogenous substances is noted.