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Smog chamber/FTIR techniques were used to investigate the kinetics and mechanism of the Cl atom and OH radical initiated oxidation of 2,2-dichloroethanol at (296 ± 1) K. Relative rate methods were used to measure k(Cl + CHCl2CH2OH) = (5.87 ± 0.96) × 10-12 and k(OH + CHCl2CH2OH) = (5.54 ± 1.94) × 10-13 cm3 molecule-1 s-1. Chlorine atom initiated oxidation of CHCl2CH2OH in one atmosphere of air gives HCOCl, CHCl2CHO, and COCl2 in yields of (62 ± 5)%, (39 ± 10)%, and (8 ± 2)%, respectively. The rate constant k(Cl + CHCl2CHO) = (8.3 ± 16) × 10-12 cm3 molecule-1 s-1 was determined and the IR spectra of CHCl2CHO is reported for the first time. The atmospheric lifetime for CHCl2CH2OH is estimated as 21 days. The experimental results are discussed in the context of the atmospheric chemistry of chlorinated alcohols.

The incorporation of 2,2,2-trichloroethanol in polyacrylamide gels allows for fluorescent visualization of proteins following electrophoresis. Ultraviolet-light exposure, in the presence of this trichlorinated compound, results in a covalent modification of the tryptophan indole ring that shifts the fluorescent emission into the visible range. Based on this principle, we used 2,2,2-trichloroethanol to develop a microplate format protein quantification assay based on the fluorescent signal generated by modified proteins. We also demonstrated a specific fluorescent emission of 2,2,2-trichloroethanol-labeled protein at 450 nm, with a 310 nm excitation, resulting from modification of both tryptophan and tyrosine residues. Following optimization, this protein quantification assay displayed superior sensitivity when compared to UV absorbance at 280 nm (A280), and enabled quantification beyond the linear range permitted by the Bradford method. This 100 μL assay displayed a sensitivity of 10.5 μg in a range up to at least 200 μg. Furthermore, we extended the utility of this method through the development of a 20 μL low-volume assay, with a sensitivity of 8.7 μg tested up to 100 μg, which enabled visualization of proteins following SDS-PAGE. Collectively, these results demonstrate the utility of 2,2,2-trichloroethanol-based protein quantification and demonstrates the protein visualization in polyacrylamide gels based on 2,2,2-trichloroethanol-labeling pre-electrophoresis.

The identification of initial lead conditions for successful protein crystallization is crucial for structural studies using X-ray crystallography. In order to reduce the number of false-negative conditions, an emerging number of fluorescence-based methods have been developed which allow more efficient identification of protein crystals and help to distinguish them from salt crystals. Detection of the native tryptophan fluorescence of protein crystals is one of the most widely used methods. However, this method can fail owing to the properties of the crystallized protein or the chemical composition of the crystallization trials. Here, a simple, fast and cost-efficient method employing 2,2,2-trichloroethanol (TCE) has been developed. It can be performed with a standard UV-light microscope and can be applied to cases in which detection of native tryptophan fluorescence fails. In four test cases this method had no effect on the diffraction properties of the crystals and no structural changes were observed. Further evidence is provided that TCE can be added to crystallization trials during their preparation, making this method compatible with high-throughput approaches.

The synthetic organic chemical, 1,2-dichloroethane (1,2-DCE), can cause brain edemas under subacute poisoning. Our previous studies indicated that neuroinflammation could be induced due to astrocytes and microglia activation during brain edemas in 1,2-DCE-intoxicated mice. However, the crosstalk between these two glial cells in 1,2-DCE-induced neuroinflammation remained unclear. In this study, primary cultured rat astrocytes and microglia, as well as an immortalized microglia cell line were employed to study the effects of 2-chloroethanol (2-CE, a 1,2-DCE intermediate metabolite in vivo) treated astrocytes on microglia polarization. Our current results revealed that 2-CE treated rat astrocytes were activated through p38 mitogen-activated protein kinase (p38 MAPK)/nuclear factor-κB (NF-κB), and activator protein-1 (AP-1) signaling pathways. Theses pathways were triggered by reactive oxygen species (ROS) produced during 2-CE metabolism. Also, astrocytes were more sensitive to 2-CE effects than microglia. Interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and inducible nitric oxide synthase (iNOS) expressions were upregulated in 2-CE-induced reactive astrocytes, enhancing IL-1β, TNF-α, and nitric oxide (NO) excretions, which stimulated microglia polarization. Therefore, the neuroinflammation induced by 1,2-DCE in mice's brains is probably triggered by reactive astrocytes.

Cyclization of substituted thiosemicarbazides in alkaline medium was used to synthesize the corresponding 3-thio-4-benzyl(cyclohexyl, allyl)-5-(4-benzyloxyphenyl)-1,2,4-triazoles. These compounds were 3-S-alkylated with ethylene chlorohydrin, chloroacetamide, 3-bromo-4-methoxybenzyl chloride, and chloroacetic, 2-bromopropionic, and 2-bromocaproic acids. Aminomethylation and oxymethylation reactions were studied. 2-N-Aminomethylene and 2-N-oxymethylenetriazoline-3-thiones were prepared. The antitumor activity of the compounds synthesized here were studied.

Brain edema caused by subacute poisoning with 1,2-dichloroethane (1,2-DCE) has gained much attention during recent years, but its underlying mechanism is poorly understood. As an intermediate metabolite of 1,2-DCE in vivo, 2-chloroethanol (2-CE) can be transformed into chloroacetaldehyde and reactive oxygen species (ROS) through cytochrome P450 2E1 (CYP2E1) mediated metabolism. In previous studies, it was found that CYP2E1 expression is enhanced in the brain of mice treated with 1,2-DCE. This study was designed to verify the roles of CYP2E1 overexpression in 2-CE induced cytotoxicity in rat astrocytes, and the contribution of specific signaling molecules to the upregulation of CYP2E1 expression caused by 2-CE. The results of this study demonstrate that treatment with 2-CE can enhance CYP2E1 protein and mRNA levels, cause an increase in ROS and MDA levels, and higher percentages of apoptotic cells in rat astrocytes. Pretreatment with either diallyl sulfide or vitamin C, the inhibitor of CYP2E1 or scavenger of ROS, respectively, can suppress the levels of CYP2E1 expression, ROS and MDA, ameliorate cell apoptosis, and attenuate phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) in these cells. Additionally, pretreatment with the inhibitor of either ERK1/2 or transcriptional factor specificity protein 1 (SP1) can suppress the CYP2E1 expression, and alleviate the oxidative damage caused to these cells. In conclusion, our findings demonstrate that CYP2E1 overexpression plays a crucial role in 2-CE induced oxidative damage of rat astrocytes, and that CYP2E1 expression is upregulated partially through the activation of the ERK1/2 and SP1 signaling pathways by ROS generated during CYP2E1-mediated 2-CE metabolism. This study provides novel information that can be used in elucidating the mechanism by which 1,2-DCE induces brain edema.

Triclofos sodium (TCS) and chloral hydrate (CH) are widely used as sedatives for children, but no analytical method to simultaneously monitor concentrations of blood TCS, CH and their metabolites, trichloroacetic acid (TCA) and trichloroethanol (TCEOH), has been reported. The present study aimed to develop a simple analytical method for TCS and its metabolites (TCA, TCEOH and CH) in small-volume plasma from children. After acidification of specimens, TCS formic acid adduct or the metabolites derivatized using water/sulfuric acid/methanol (6:5:1, v/v) were measured by combined use of liquid chromatography tandem-mass spectrometry and gas chromatography mass-spectrometry. The limits of detection and quantification levels (µg/ml) were 0.10 and 0.29 for TCS, 0.24 and 0.72 for TCA, 0.10 and 0.31 for TCEOH, and 0.25 and 0.76 for CH, respectively. The mean recoveries were 82.8–107% for TCS, 85.4–101% for TCA, 91.6–107% for TCEOH, and 88.9–109% for CH. Within-run and between-run precision (percent of relative standard deviation, %RSD) using this method ranged from 1.1 to 15.7% and 3.6 to 13.5%, respectively, for TCS and all of its metabolites. The calibration curves were obtained with standard spiked plasma, and all of the coefficients of determination were more than 0.975. Subsequently, we applied the present method to plasma taken from five children after sedation induced by CH and TCS. In addition to TCS and CH, elevated TCA and TCEOH concentrations were detected. This new method can be applied for the pharmacokinetic analysis of TCS and its metabolites and the determination of the optimal TCS dosage in children.

2,2,2-Trichloroethanol (TCOH) is responsible for the pharmacological actions of chloral hydrate (CH), and is a major metabolite of trichloroethylene. Human exposure to TCOH is known to be increasing. Recently, it was reported that TCOH causes a significant phase delay of Per2 expression in mouse liver when injected daily over the course of several days. However, it is not clear whether TCOH directly modulates the molecular clock. In the present study we used a cell-based assay system to test this possibility. We found that the daily oscillation period of Bmal1 was lengthened to 3 h following treatment with 1.5 mM TCOH, and increased to 5 h with 3 mM TCOH treatment. However, low concentrations of TCOH had no noticeable effects. The effect of TCOH on Per2 oscillation was marginal. Interestingly, serum from rats anesthetized with CH also modulated Bmal1 period, suggesting that exposure to anesthesia should be taken into consideration for circadian rhythm studies. In summary, our study reveals a direct regulation of TCOH on molecular clock.

It was recently demonstrated that some drugs modulate in vitro metabolism of trichloroethylene (TCE) in humans and rats. The objective was to assess in vivo interactions between TCE and three drugs: naproxen (NA), valproic acid (VA), and salicylic acid (SA). Animals were exposed to TCE by inhalation (50 ppm for 6 h) and administered a bolus dose of drug by gavage, equivalent to 10-fold greater than the recommended daily dose. Samples of blood, urine, and collected tissues were analyzed by headspace gas chromatography coupled to an electron capture detector for TCE and metabolites (trichloroethanol [TCOH] and trichloroacetate [TCA]) levels. Coexposure to NA and TCE significantly increased (up to 50%) total and free TCOH (TCOHtotal and TCOHfree, respectively) in blood. This modulation may be explained by an inhibition of glucuronidation. VA significantly elevated TCE levels in blood (up to 50%) with a marked effect on TCOHtotal excretion in urine but not in blood. In contrast, SA produced an increase in TCOHtotal levels in blood at 30, 60, and 90 min and urine after coexposure. Data confirm in vitro observations that NA, VA, and SA affect in vivo TCE kinetics. Future efforts need to be directed to evaluate whether populations chronically medicated with the considered drugs display greater health risks related to TCE exposure.

In this study, recipe optimization of Leuco Crystal Violet (LCV) micelle gels made with the surfactant Cetyl Trimethyl Ammonium Bromide (CTAB) and the chemical sensitizer 2,2,2-trichloroethanol (TCE) was aided by a two-level three-factor designed experiment. The optimized recipe contains 0.75 mM LCV, 17.0 mM CTAB, 120 mM TCE, 25.0 mM tri-chloro acetic acid (TCAA), 4 wt% gelatin and ~96 wt% water. Dose sensitivity of the optimized gel is 1.5 times higher than that of Jordan's standard LCV micelle gel. Spatial integrity of the 3D dose distribution information in 1L phantoms filled with this recipe is maintained for120 d. Unfortunately, phantoms made using the optimized recipe showed dose-rate dependence (14% difference in optical attenuation at the peak dose using electron beam irradiations at 100 and 400 MU min(-1)). Further testing suggests that the surfactant CTAB is the cause of this dose rate behaviour.

The first organocatalytic enantioselective oxidative C-H functionalization of N-acyl tetrahydroisoquinolines with vinyl and aryl boronates promoted by a chiral Brønsted acid is described. This metal-free process tolerates a wide range of electronically varied N-acyl tetrahydroisoquinolines and structurally diverse boronates with good to excellent enantioselectivities.

New acyclic pyrimidine nucleosides, analogs of the antiviral drug acyclovir, were synthesized starting from 6-chloropyrimidine-2,4(1H,3H)-dione. The addition of side carbohydrate chain to the N1 or N3 atoms of the heterocyclic base with formation of N1- and N3-substituted isomers, respectively, was confirmed by 1H NMR and X-ray analysis. N1- and N3-Substituted 6-chloropyrimidine-2,4(1H,3H)-diones were subjected to amination with secondary amines, and cyclocondensation of 6-allylamino derivative afforded N1-substituted pyrido[2,3-d]pyrimidine.

bis(2-chloroethoxy)methane was synthesized by the reaction of ethylene chlorohydrin and Oligopolyformaldehyde under sulfuric acid catalysis. optimum reaction conditions obtained were as follows: the molar ratio of Oligopolyformaldehyde and ethylene chlorohydrin of 1.2:2, catalyst dosage was 5‰mass fraction of ethylene chlorohydrin, toluene were chose as water-carrying agent, All reactant were refluxed on temperature of 110°C until no water generated. Under the optimum conditions the yield of bis(2-chloroethoxy)methane was 97.7%. The structure of bis(2-chloroethoxy)methane were conformed by ATR IR. The purity of bis(2-chloroethoxy)methane were 99% by gas chromatographic detection.

Gas chromatography-mass spectrometry was used to analyse ethylene oxide (EO) in 63 samples of dried vegetable materials for food use derived from import commodities and subjected to quality control for three food-transformation industries. EO residues were quantified through the determination of ethylene chlorohydrin (ECH). About 29% of the samples analysed contained more than 0.3 mg kg(-1) of EO. Thus, this specific analytical control limited to 20% of import aromatic matters needs to be increased. This paper demonstrates the importance of this specific control considering the banned use of microbial decontamination EO treatment in the European Union.

3-(5-Methylbenzofuryl)-4-phenyl(benzyl, allyl)-5-mercapto-1,2,4-triazoles were synthesized by cyclization of the corresponding substituted thiosemicarbazides. S-alkylation, N-aminomethylation, and N-hydroxymethylation of the 5-mercaptotriazoles by ethylene chlorohydrin, chloroacetamide, and chloroacetic acid produced N-aminomethylene- and N-hydroxymethylenetriazoline-5-thiones. The antitumor activity of the synthesized compounds was studied.

The genotoxic effects of oxidative metabolites of trichloroethylene (TCE), namely chloral hydrate, trichloroacetic acid (TCA), dichloroacetic acid (DCA), and trichloroethanol (TCEOH) were examined in human peripheral blood lymphocytes. In this context, lymphocytes were exposed in vitro to 25, 50, and 100 μg/ml concentrations of these metabolites separately for a period of 48 h and examined for micronucleus (MN) induction through flow cytometer. At 50 μg/ml TCE metabolites, TCA (6.33 ± 0.56 %), DCA (5.06 ± 0.55), and TCEOH (4.70 ± 1.73) induced highly significant (p

The industrial solvent trichloroethylene (TCE) has been reported to increase the excretion of formic acid in the urine of male Fischer 344 (F-344) rats following large oral doses. We have examined the dose-response relationship for formic aciduria in male and female Fischer 344 rats, the effect of some known metabolites of TCE and examined the response in male Wistar rats to help understand its relevance to renal toxicity. We report that doses of TCE as low as 8 mg/kg for 3 days to both male and female F344 rats produced formic aciduria. The formic aciduria was time-dependent being more marked after 3 doses compared to one dose in male F344 rats and to a lesser extent in female F344 rats. TCE administration to male Wistar rats produced less formic aciduria than in male F344 rats, indicating a strain difference in response. As TCE is primarily metabolised by cytochrome P450 2E1, Wistar rats were administered inducers of cytochrome P450 2E1 followed by TCE, this increased formic acid excretion to a concentration similar to that observed in male F344 rats, indicating a role for P450. Administration of the major metabolites of TCE, trichloroethanol and trichloroacetic acid to male F344 rats also produced a marked and sustained formic aciduria, while the metabolite of TCE formed via glutathione conjugation had no effect on formic acid excretion. The mechanism whereby this response occurs is currently not understood, but the formic acid excreted is not a metabolite of TCE, but appears to be due to interference with the metabolic utilisation of formate by a down stream metabolite of TCE. Over the three days of the studies no histopathological evidence of kidney toxicity was observed in F344 rats given TCE, indicating that the perturbation of formate metabolism does not lead to acute renal injury.

International audience; OBJECTIVES: To describe urine levels of metabolites of glycol ethers and chlorinated solvents in a sample of pregnant women from the general population, to study their occupational and non-occupational determinants and to compare them with the results of indirect assessment methods of solvent exposure. METHODS: A sample of 451 pregnant women was randomly selected from a general population cohort. At inclusion, the women in this sample completed a self-administered questionnaire about their social and medical characteristics, occupation and exposure to different products at work and in non-occupational activities. Occupational exposure to solvents was assessed from the woman's self-report and from a job-exposure matrix. Eight alkoxycarboxylic acids and trichloroacetic acid and trichloroethanol were measured with chromatography in urine samples collected at inclusion. Associations between metabolite levels and job titles, exposure to products used at work, and solvent exposure were studied. RESULTS: The different glycol ether metabolites were detected in 5.3%-96.4% of the urine samples, trichloroacetic acid in 6.4% and trichloroethanol in 5.5%. Nurses had butoxyacetic acid and phenoxyacetic acid in their urine most often, whereas methoxyethoxyacetic acid was the most frequent among nursing aides. Among cleaners, ethoxyacetic acid and ethoxyethoxyacetic acid were the most frequent. The occupation of hairdresser was associated with urinary excretion of ethoxyacetic acid, ethoxyethoxyacetic acid, butoxyacetic acid and phenoxyacetic acid. Among the women classified as exposed to solvents, the agents identified most often were ethoxyacetic acid, ethoxy-ethoxyacetic acid, butoxyacetic acid, phenoxyacetic acid, trichloroacetic acid and trichloroethanol. Ethoxyethoxyacetic acid was the only metabolite associated with non-occupational exposure. CONCLUSIONS: Metabolites of glycol ethers and chlorinated solvents were present at low levels in the urine of pregnant women. Most metabolites were associated with occupational exposure.

Ethylene chlorohydrin when reacted with elemental chalcogens or dimethyl dichalcogenides in the hydrazine hydrate-alkali system forms chalcogen-containing analogs of ethylene glycol and its derivatives (dichalcogenated β-diglycols, chalcogenated ethanols, and chalcogenated methyl cellosolves).

Chloral hydrate (CH) is a short-lived intermediate in the metabolism of trichloroethylene (TRI). TRI, CH, and two common metabolites, trichloroacetic acid (TCA) and dichloroacetic acid (DCA) have been shown to be hepatocarcinogenic in mice. To better understand the pharmacokinetics of these metabolites of TRI in humans, eight male volunteers, aged 24-39, were administered single doses of 500 or 1,500 mg or a series of three doses of 500 mg given at 48 h intervals, in three separate experiments. Blood and urine were collected over a 7-day period and CH, DCA, TCA, free trichloroethanol (f-TCE), and total trichloroethanol (T-TCE=trichloroethanol and trichloroethanol-glucuronide [TCE-G]) were measured. DCA was detected in blood and urine only in trace quantities (

Nonfatal acute inhalation of trichloroethylene (TRI) at work was described. The subject, male, 54 years old, was drawn unconscious by a metal-degreasing machine and immediately sheltered in intensive care unit. Other than basic life support and common laboratory indices, blood and urine were collected to measure dose and kidney effect parameters such as TRI in blood and urine, trichloroethanol (TCE) and trichloroacetic acid (TCA) in urine, and total urinary proteins (TUP), urinary glutamine synthetase (GS) and urinary N-acetyl-beta-D-glucosaminidase (NAG). Two hours after accident, TRI in blood was 9 mg/l, but after 38 h it was below 1 mg/l. TCE and TCA have a peak 11 and 62 h after poisoning, respectively. Acute renal involvement was revealed by a peak of urinary proteins and enzymes 7 h after exposure with a second peak 74 h after. Seven day after hospitalisation the patient was dismissed with complete recovery. This nonfatal intoxication with TRI shows that the exposure was approximately 150 ppm, three times the ACGIH TLV (50 ppm) and that kidney was the only organ affected. Urinary enzymes, in particular GS, are good indices to monitor transient effects of TRI on the kidney.

Radiochromic leuco crystal violet (LCV) micelle gel dosimeters are promising three-dimensional radiation dosimeters because of their spatial stability and suitability for optical readout. The effects of surfactant type and surfactant concentration on dose sensitivity of LCV micelle gels are tested, demonstrating that dose sensitivity and initial colour of the gel increases with increasing Triton x-100 (Tx100) concentration. Using Cetyl Trimethyl Ammonium Bromide (CTAB) in place of Tx100 produces gels that are nearly colourless prior to irradiation, but reduces the dose sensitivity. The separate effects of Tri-chloro acetic acid concentration and pH are investigated, revealing that controlling the pH near 3.6 is crucial for achieving high dose sensitivity. The sensitizing effect of chlorinated species on dose sensitivity is tested using 2,2,2-trichloroethanol (TCE), chloroform, and 1,1,1-trichloro-2-methyl-2-propanol hemihydrate. TCE gives the largest improvement in dose sensitivity and is recommended for use in micelle gel dosimeters because it is less volatile and safer to use than chloroform. Preliminary experiments on a new gel containing CTAB as the surfactant and TCE show that this new gel gives a dose sensitivity that is 24% higher than that of previous LCV micelle gels and is nearly colourless prior to irradiation.

Alkylation of 6-methyluracil, 5-fluorouracil, uracil-5-ammonium sulfate, 5-hydroxyuracil, 5-hydroxy-6-methyluracil, 3,6-dimethyl-5-hydroxyuracil, and 1,3,6-trimethyl-5-hydroxyuracil with ethylene chlorohydrin in water-alcohol medium in the presence of KOH was investigated.

Bayesian population analysis of a harmonized physiologically based pharmacokinetic (PBPK) model for trichloroethylene (TCE) and its metabolites was performed. In the Bayesian framework, prior information about the PBPK model parameters is updated using experimental kinetic data to obtain posterior parameter estimates. Experimental kinetic data measured in mice, rats, and humans were available for this analysis, and the resulting posterior model predictions were in better agreement with the kinetic data than prior model predictions. Uncertainty in the prediction of the kinetics of TCE, trichloroacetic acid (TCA), and trichloroethanol (TCOH) was reduced, while the kinetics of other key metabolites dichloroacetic acid (DCA), chloral hydrate (CHL), and dichlorovinyl mercaptan (DCVSH) remain relatively uncertain due to sparse kinetic data for use in this analysis. To help focus future research to further reduce uncertainty in model predictions, a sensitivity analysis was conducted to help identify the parameters that have the greatest impact on various internal dose metric predictions. For application to a risk assessment for TCE, the model provides accurate estimates of TCE, TCA, and TCOH kinetics. This analysis provides an important step toward estimating uncertainty of dose-response relationships in noncancer and cancer risk assessment, improving the extrapolation of toxic TCE doses from experimental animals to humans.

BACKGROUND: Trichloroethylene (TCE) is a suspected human carcinogen and a common groundwater contaminant. Chloral hydrate (CH) is the major metabolite of TCE formed in the liver by cytochrome P450 2E1. CH is metabolized to the hepatocarcinogen trichloroacetate (TCA) by aldehyde dehydrogenase (ALDH) and to the noncarcinogenic metabolite trichloroethanol (TCOH) by alcohol dehydrogenase (ADH). ALDH and ADH are polymorphic in humans, and these polymorphisms are known to affect the elimination of ethanol. It is therefore possible that polymorphisms in CH metabolism will yield subpopulations with greater than expected TCA formation with associated enhanced risk of liver tumors after TCE exposure. METHODS: The present studies were undertaken to determine the feasibility of using commercially available, cryogenically preserved human hepatocytes to determine simultaneously the kinetics of CH metabolism and ALDH/ADH genotype. Thirteen human hepatocyte samples were examined. Linear reciprocal plots were obtained for 11 ADH and 12 ALDH determinations. RESULTS: There was large interindividual variation in the Vmax values for both TCOH and TCA formation. Within this limited sample size, no correlation with ADH/ALDH genotype was apparent. Despite the large variation in Vmax values among individuals, disposition of CH into the two competing pathways was relatively constant. CONCLUSIONS: These data support the use of cryopreserved human hepatocytes as an experimental system to generate metabolic and genomic information for incorporation into TCE cancer risk assessment models. The data are discussed with regard to cellular factors, other than genotype, that may contribute to the observed variability in metabolism of CH in human liver. This work was supported by a U.S. Department of Energy cooperative agreement (DE-FC02-98CH1092).

The dopaminergic neurons of the ventral tegmental area (DA VTA neurons) have been implicated in the reinforcing properties of drugs of abuse, including ethanol (ethyl alcohol). Ethanol increases the spontaneous firing frequency of DA VTA neurons in vitro, in both brain slices and acutely dissociated neurons, and also in vivo. In many systems, longer n-alkyl alcohols have a more potent effect than ethanol, and the potency is a function of the number of carbons in the alkyl chain. We studied n-alcohols of chain length 1 (methanol) to 5 (pentanol) on the firing rate of DA VTA neurons in brain slice preparations. All of the alcohols studied produced increases in the spontaneous firing frequency in DA VTA neurons; as the chain length increased, lower concentrations of the alcohols were needed to produce the same percentage increase in firing. With very high concentrations of all the alcohols except methanol, we observed apparent depolarization block of firing. In addition, trichloroethanol (TCE), the active metabolite of chloral hydrate, increased the firing frequency of DA VTA neurons, and the EC(40) (concentration to produce a 40% increase in firing rate) of TCE was below that of ethanol. These studies indicate that excitation of VTA dopamine neurons by n-alcohols is related to the chain length of the carbons. This is likely to be a characteristic of the ethanol-sensitive element of DA VTA neurons and may be useful in identifying the element of the membrane that is responsible for ethanol-induced excitation.

The aim of the present study was to develop a method of urinalysis for trichloroacetic acid (TCA) and trichloroethanol (TCE), and therefore total trichloro-compounds (TTC) as the sum, with least use of hazardous chemicals, being green in that sense. After acid hydrolysis followed by dilution with an ethanol (EtOH)-methanol (MeOH)-water mixture, capillary gas-choromatography with an electron-capture detector can quantify TCA and TCE in the diluted hydrolyzate. Comparison studies showed that the results were identical among three methods, i.e., 1. the method developed in the present study, 2. a head-space GC with acid hydrolysis of conjugated TCE and methyl-esterification of TCA1), and 3. traditional colorimetry with Fujiwara reaction2). When applied to exposure - excretion analysis, the three methods gave results reproducible to each other. Over-all evaluation therefore was such that the method developed in the present study is as equally reliable as previously developed methods. It should be further noted that the procedures are very simple, with minimum use of occupationally or environmentally hazardous chemicals. In case the determination of only TCA is requested, it is possible to skip the hydrolysis step so that the treatment prior to the GC analysis is even simpler, i.e., just a 60-fold dilution of the urine sample with the EtOH-MeOH-water mixture. It was also demonstrated that correction of urinary analyte levels for urine density in terms of creatinine or specific gravity did not improve the correlation with the intensity of TRI exposure.

The present study was designed to examine the hypothesis that liver tissue repair induced after exposure to chloroform (CF) + trichloroethylene (TCE) + allyl alcohol (AA) ternary mixture (TM) is dose-dependent similar to that elicited by exposure to these compounds individually. Male Sprague Dawley (S-D) rats (250-300 g) were administered with fivefold dose range of CF (74-370 mg/kg, ip), and TCE (250-1250 mg/kg, ip) in corn oil and sevenfold dose range of AA (5-35 mg/kg, ip) in distilled water. Liver injury was assessed by plasma alanine amino transferase (ALT) activity and liver tissue repair was measured by (3) H-thymidine incorporation into hepatonuclear DNA. Blood and liver levels of parent compounds and two major metabolites of TCE [trichloroacetic acid (TCA) and trichloroethanol (TCOH)] were quantified by gas chromatography. Blood and liver CF and AA levels after TM were similar to CF alone or AA alone, respectively. However, the TCE levels in blood and liver were substantially decreased after TM in a dose-dependent fashion compared to TCE alone. Decreased plasma and liver TCE levels were consistent with decreased production of metabolites and elevated urinary excretion of TCE. The antagonistic interaction resulted in lower liver injury than the summation of injury caused by the individual components at all three-dose levels. On the other hand, tissue repair showed a dose-response leading to regression of injury. Although the liver injury was lower and progression was contained by timely tissue repair, 50% mortality occurred only with the high dose combination, which is several fold higher than environmental levels. The mortality could be due to the central nervous system toxicity. These findings suggest that exposure to TM results in lower initial liver injury owing to higher elimination of TCE, and the compensatory liver tissue repair stimulated in a dose-dependent manner mitigates progression of injury after exposure to TM.

A sensitive and reproducible method is described for the analysis of trichloroacetic acid in urine and 1,1,1-trichloroethane in blood using dynamic headspace GC/MS. Samples were analyzed using the soil module of a modified purge and trap autosampler to facilitate the use of disposable purging vessels. Coefficients of variation were below 3.5% for both analytes, and response was linear in the range of 0.01-7.0 microg/ml for trichloroacetic acid and 0.9 ng/ml-2.2 microg/ml for 1,1,1-trichloroethane. Attempts at using dynamic headspace for the analysis of trichloroethanol in urine were unsuccessful.

An α1-acid glycoprotein, immobilized on silica (Chiral-AGP) is one of the most widely used chiral stationary phases for the enantiomeric separation of a wide variety of chiral drugs with several applications in the biological and clinical field. The aim of this work was to study the sorption properties of the AGP-based stationary phase, which may have crucial importance for enantioselectivity. New binding data to the mechanism of the chromatographic separation are presented. The sorption of both organic solvents, i.e., acetonitrile and dioxane, shows remarkable pH dependency. A fluorescence quenching study was carried out to elucidate structural changes of AGP in the presence of acetonitrile using 2,2,2-trichloroethanol as fluorescence quencher. Chirality 15:377–381, 2003. © 2003 Wiley-Liss, Inc.

The tumorigenicity of chloral hydrate (CH), trichloroacetic acid (TCA), trichloroethanol (TCE), malondialdehyde (MDA), crotonaldehyde, acrolein, and 4-hydroxy-2-nonenal (HNE) was tested in the B6C3F(1) neonatal mouse. Mice were administered i.p. injections of CH (1000, 2000, 2500, and 5000 nmol per animal), TCA (1000 and 2000 nmol), TCE (1000 and 2000 nmol), MDA (1500 and 3000 nmol), crotonaldehyde (1500 and 3000 nmol), acrolein (75 and 150 nmol), and HNE (750 and 1500 nmol) at 8 and 15 days of age. At 12 months, only male mice treated with the positive control chemicals, 4-aminobiphenyl (500 and 1000 nmol) and benzo[a]pyrene (150 and 300 nmol), had incidences of tumors in the liver significantly higher than the solvent control. Additional male mice were dosed as described above and their livers were excised at 24, 48 h, and 7 days after the final dose. Liver DNA was isolated and analyzed by 32P-postlabeling/high-performance liquid chromatography (HPLC) and HPLC/electrochemical detection for MDA-derived adduct (M(1)G) and 8-oxo-2'-deoxyguanosine (8-OHdG) formation, respectively. At 24 and 48 h after the final dose, CH- and TCA-treated mice exhibited significantly higher M(1)G levels than the controls. 8-OHdG formation was also induced by CH, TCA, and MDA. These results suggest that under these experimental conditions the B6C3F(1) neonatal mouse is not sensitive to carcinogens that induce an increase in endogenous DNA adduct formation through lipid peroxidation or oxidative stress.

Some challenging pharmaceutical applications performed with state-of-the-art capillary gas chromatography (CGC) are presented. For assay and purity determinations cool on-column (COC) injection is the preferred injection technique. A fast CGC headspace method is described to determine residual solvents in pharmaceutical products. Ethylene oxide and ethylene chlorohydrin, originating from the sterilisation of packaging materials, were measured in pharmaceutical formulations in a fully automated sequence with excellent retention time and peak-area reproducibility.

We investigated the effects of 2,2,2-trichloroethanol (TCE), the active metabolite of chloral hydrate, on large-conductance calcium-activated K+ channels (BKCa channels) of dorsal root ganglion (DRG) neurones. In outside-out patches, 2 and 5 mM TCE increased the open probability of BKCa channels to 1.7-fold and 2.8-fold of control, respectively. In 50% of the cells investigated (group A) the action potential (AP) was shortened reversibly by TCE by 20% and the whole-cell outward-current was increased by 44%. Both effects could be antagonized by iberiotoxin. In a second group of neurone (group B), TCE prolonged the AP duration. The effects of TCE in group A, which was 20-fold more potent than ethanol on BKCa channels and AP might contribute to the described analgesic effect of chloral hydrate.

Chloral hydrate, a sedative/hypnotic agent widely used in the pediatric population, is converted to the active metabolite 2,2,2-trichloroethanol (TCE) in the liver. Tryptophan fluorescence quenching has been used previously to show that halothane and chloroform bind saturably to serum albumin, and a similar approach is used here to demonstrate that TCE also binds to albumin. TCE quenches the steady-state tryptophan fluorescence of bovine serum albumin (BSA) in a concentration-dependent, saturable manner with a KD = 3.3 ± 0.3 mmol/l. Unlike halothane and chloroform, however, TCE also elicits a concentration-dependent blue-shift in the fluorescence emission spectrum of BSA and human serum albumin. This indicates that TCE induces a conformational change in the protein, causing the tryptophan to experience a change in its chemical environment, thus shifting the peak of the emission spectrum. Circular dichroism spectroscopy revealed a decrease in the α-helical content of BSA from 65.8 ± 0.4 to 62.9 ± 0.6% when TCE was present at a concentration of 30 mmol/l, providing further evidence for a conformational change. There is evidence that TCE potentiates the action of ligand-gated ion channels such as the GABAA and 5-HT3 receptors, and the present results suggest that anesthetic alcohols may act by binding to these proteins and inducing structural changes that may in turn alter protein function.

Photoreaction of indole containing compounds with chloroform and other trichlorocompounds generates products with redshifted fluorescence. In proteins, this reaction can be used for the fluorescent detection of proteins. Little characterization of products generated through the photochemical reaction of indoles with halocompounds has been done, yet is fundamental for the development of other fluorophores, protein labeling agents, and bioactive indole derivatives. Here, we have characterized which isomers form in the photoreaction between tryptophan and chloroform using (1)H-NMR of tryptophan and methylated derivatives to reveal that the two major products that are formed result from modification at the 4- and 6-carbon positions of the indole ring. Reaction at position 6 generates 6-formyl tryptophan and the reaction at position 4 generates an imine because the formyl derivative that is initially formed reacts further with the tryptophan amine group. The spectroscopic properties and product molecular weights of photoproducts formed from photoreaction of tryptophan with other trihalo and monohalocompounds are also determined. The indole ring of tryptophan can be modified with various additions from halocompounds, including the addition of labels to the indole ring via methylene groups. This opens possibilities for generating novel tryptophan based fluorophores and protein labeling strategies using this photochemistry.

Trichloroethylene (TCE) is widely used as a cleaning and decreasing agent and has been shown to cause liver tumours in rodents and a small incidence of renal tubule tumours in male rats. The basis for the renal tubule injury is believed to be related to metabolism of TCE via glutathione conjugation to yield the cysteine conjugate that can be activated by the enzyme cysteine conjugate β-lyase in the kidney. More recently TCE and its major metabolite trichloroethanol (TCE-OH) have been shown to cause formic aciduria which can cause renal injury after chronic exposure in rats. In this study we have compared the renal toxicity of TCE and TCE-OH in rats to try and ascertain whether the glutathione pathway or formic aciduria can account for the toxicity. Male rats were given TCE (500 mg/kg/day) or TCE-OH at (100 mg/kg/day) for 12 weeks and the extent of renal injury measured at several time points using biomarkers of nephrotoxicity and prior to termination assessing renal tubule cell proliferation. The extent of formic aciduria was also determined at several time points, while renal pathology and plasma urea and creatinine were determined at the end of the study. TCE produced a very mild increase in biomarkers of renal injury, total protein, and glucose over the first two weeks of exposure and increased Kim-1 and NAG in urine after 1 and 5 weeks exposure, while TCE-OH did not produce a consistent increase in these biomarkers in urine. However, both chemicals produced a marked and sustained increase in the excretion of formic acid in urine to a very similar extent. The activity of methionine synthase in the liver of TCE and TCE-OH treated rats was inhibited by about 50% indicative of a block in folate synthesis. Both renal pathology and renal tubule cell proliferation were reduced after TCE and TCE-OH treatment compared to controls. Our findings do not clearly identify the pathway which is responsible for the renal toxicity of TCE but do provide some support for metabolism via glutathione conjugation.

Trichloroethylene (TCE) is a widespread and persistent environmental contaminant. Recently, plants, poplar trees in particular, have been investigated as a tool to remove TCE from soil and groundwater. The metabolism of TCE in plants is being investigated for two reasons: one, plant uptake and metabolism represent an important aspect of the environmental fate of the contaminant; two, metabolism pattern and metabolite identification will help assess the applicability of phytoremediation. It was previously shown that TCE metabolites in plants are similar to ones that result from cytochrome P450-mediated oxidation in mammals: trichloroethanol, trichloroacetate and dichloroacetate. Our measurements indicate that one of these metabolites, trichloroethanol, is further glycosylated in tobacco and poplar. The glycoside was detected in all tissues (roots, stems and leaves) in comparable levels, and was at least 10 fold more abundant than free trichloroethanol. The glycoside in tobacco was identified as the ss-D-glucoside of trichloroethanol by comparison of the mass spectra and the chromatographic retention time of its acetylation product to that of the synthesized standard. Trichloroethanol and its glucoside did not persist in plant tissue once plants are removed from TCE contaminated water, indicating further metabolism.

We have synthesized 3-substituted 4-alkyl-5-imino-4,5-dihydro-1,2,4-thiadiazoles by reaction of 3-alkyl(benzyl)thio-5-amino-1,2,4-thiadiazoles with methyl iodide or ethylene chlorohydrin. In the reaction with epichlorohydrin, addition of an oxirane molecule occurs with formation of tetrahydropyrimido[2,1-b]-1,2,4-thiadiazoles.

The collagen gel sandwich culture of hepatocytes has been proposed as one of the most suitable culture models available for biotransformation studies of xenobiotics. It is a complex model which imitates the cascade of enzymatic events of in vivo biotransformation and allows investigation of biological endpoints under realistic conditions. The biotransformation of trichloroethylene (TRI) has been studied in this model using rat hepatocytes. Headspace gas chromatographic measurements revealed that hepatocytes, cultured for 4 days in this in vitro system, metabolised TRI into the major oxidative metabolites trichloroacetic acid (TCA) and trichloroethanol (TCE). Cultured hepatocytes were exposed either to TRI, or to TCA and TCE. Endpoints studied were albumin secretion and the cytochrome P450 (CYP)-dependent enzymatic activities ethoxyresorufin O-deethylase (EROD), pentoxyresorufin O-depentylase (PROD) and N-nitrosodimethylamine demethylase (NDMA). The results show that both the parent compound and its metabolites exert specific effects on different CYP-dependent mono-oxygenase activities, as seen in vivo. It is suggested that collagen gel sandwich cultures represent a useful in vitro model for the investigation of metabolism-linked toxicity studies.

The effects of chloral hydrate and its main metabolite 2,2, 2-trichloroethanol were investigated on the (S)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)-induced rise of intracellular Ca(2+) concentration ([Ca(2+)](i)) in cultured non-pyramidal cortical neurones of rats by using single-cell fura-2 microfluorimetry. AMPA elicited a concentration-dependent effect that peaked at 300 microM (EC(50), 7. 5 microM). Responses to AMPA (30 microM) were markedly inhibited by superfusion with chloral hydrate (IC(50), 4.5 mM) or trichloroethanol (IC(50), 0.9 mM). By contrast, ethanol (100 mM) caused only slight inhibition. In conclusion, the results demonstrate that chloral hydrate and especially its metabolite trichloroethanol, inhibit the AMPA-induced rise of [Ca(2+)](i) by depressing the entry of Ca(2) into cortical neurones via the AMPA receptor-channel.

We describe a simple, precise, and sensitive assay of tetrachloroethylene and trichloroethylene in tissues, suitable both for emergency cases and forensic medicine. The method employs headspace solid phase microextraction-capillary gas chromatography and electron capture detection. The case is relative to a 45-year-old woman discovered unconscious in a laundry area. The concentrations of the solvents in tissues were determined and compared to other previously published fatalities.

Nine male and eight female healthy volunteers were exposed to 50 or 100 ppm trichloroethylene vapors for 4 h. Blood, urine, and exhaled breath samples were collected for development of a physiologically based pharmacokinetic (PBPK) model for trichloroethylene and its two major P450-mediated metabolites, trichloroacetic acid and free trichloroethanol. Blood and urine were analyzed for trichloroethylene, chloral hydrate, free trichloroethanol and trichloroethanol glucuronide, and trichloroacetic acid. Plasma was analyzed for dichloroacetic acid. Trichloroethylene was also measured in exhaled breath samples. Trichloroethylene, free trichloroethanol, and trichloroacetic acid were found in blood samples of all volunteers and only trace amounts of dichloroacetic acid (4-12 ppb) were found in plasma samples from a few volunteers. Trichloroethanol glucuronide and trichloroacetic acid were found in urine of all volunteers. No chloral hydrate was detected in the volunteers. Gender-specific PBPK models were developed with fitted urinary rate constant values for each individual trichloroethylene exposure to describe urinary excretion of trichloroethanol glucuronide and trichloroacetic acid. Individual urinary excretion rate constants were necessary to account for the variability in the measured cumulative amount of metabolites excreted in the urine. However, the average amount of trichloroacetic acid and trichloroethanol glucuronide excreted in urine for each gender was predicted using mean urinary excretion rate constant values for each sex. A four-compartment physiological flow model was used for the metabolites (lung, liver, kidney, and body) and a six-compartment physiological flow model was used for trichloroethylene (lung, liver, kidney, fat, and slowly and rapidly perfused tissues). Metabolic capacity (Vmaxc) for oxidation of trichloroethylene was estimated to be 4 mg/kg/h in males and 5 mg/kg/h in females. Metabolized trichloroethylene was assumed to be converted to either free trichloroethanol (90%) or trichloroacetic acid (10%). Free trichloroethanol was glucuronidated forming trichloroethanol glucuronide or converted to trichloroacetic acid via back conversion of trichloroethanol to chloral (trichloroacetaldehyde). Trichloroethanol glucuronide and trichloroacetic acid were then excreted in urine. Gender-related pharmacokinetic differences in the uptake and metabolism of trichloroethylene were minor, but apparent. In general, the PBPK models for the male and female volunteers provided adequate predictions of the uptake of trichloroethylene and distribution of trichloroethylene and its metabolites, trichloroacetic acid and free trichloroethanol. The PBPK models for males and females consistently overpredicted exhaled breath concentrations of trichloroethylene immediately following the TCE exposure for a 2- to 4-h period. Further research is needed to better understand the biological determinants responsible for the observed variability in urinary excretion of trichloroethanol glucuronide and trichloroacetic acid and the metabolic pathway resulting in formation of dichloroacetic acid.

Objectives. The hypothesis of this study was that metabolites of trichloroethylene (TCE), dichloroethylene (DCE) and related compounds were responsible for fetal cardiac teratogenic effects seen when TCE or DCE is consumed by pregnant rats during organogenesis. Identification of teratogenic metabolites would allow more accurate assessment of environmental contaminants and public health risks from contaminated water or possibly municipal water supplies which, when chlorinated, may produce these potentially dangerous chemicals.Background. Human epidemiologic studies and previous teratogenic studies using chick embryos and fetal rats have shown an increased incidence of congenital cardiac lesions in animals exposed to TCE and DCE.Methods. Metabolites and compounds studied in drinking water exposure included: trichloroacetic acid (TCAA), monochloroacetic acid (MCAA), trichloroethanol (TCEth), carboxy methylcystine (CMC), trichloroacetaldehyde (TCAld), dichloroacetaldehyde (DCAld), and dichlorovinyl cystine (DCVC). Compounds were administered to pregnant rats during fetal heart development.Results. Fetuses of rats receiving 2,730 ppm TCAA in drinking water were the only group that demonstrated a significant increase in cardiac defects (10.53%) compared with controls (2.15%) on a per fetus basis (p = 0.0001, Fischer’s exact test), and a per litter basis (p = 0.0004, Wilcoxon and p = 0.0015, exact permutation tests). Trichloroacetic acid also demonstrated an increased number of implantation and resorption sites (p < 0.05) over controls. Other maternal and fetal variables showed no statistically significant differences between treated and untreated groups.Conclusions. Of the metabolites tested, only TCAA appeared to be a specific cardiac teratogen in the fetus when imbibed by the maternal rat.

1. 5-HT3 receptor-mediated ion current was recorded from NCB-20 neuroblastoma cells using the whole-cell patch-clamp technique. Rapid drug superfusion was used to study the mechanism of alcohol potentiation of 5-HT3 receptor function and to analyse effects of alcohols on receptor-channel kinetics in detail. 2. Trichloroethanol (TCEt) increased in a dose-dependent way the initial slope, 20-80% rise time and measured desensitization rate of the current induced by low concentrations (1-2 microM) of 5-HT. Ethanol (EtOH) and butanol (ButOH) had similar effects on the 5-HT3 receptor-induced current. 3. TCEt and ButOH decreased the measured desensitization rate of current induced by 10 microM 5-HT, a maximally effective concentration of agonist. These alcohols also increased the relative amplitude of steady state to peak current induced by 2 or 10 microM 5-HT, indicating a possible decrease in the intrinsic rate of desensitization. 4. TCEt also decreased the deactivation rate of the current activated by 2 microM 5-HT after a short pulse of agonist application. 5. Current sweeps generated by 1 microM 5-HT in the presence or absence of 10 mM TCEt or 100 mM EtOH were well fitted using a modified standard kinetic model derived from the nicotinic acetylcholine receptor. This analysis indicated that potentiation by alcohols could be accounted for by increases in the association rate constant coupled with decreases in the dissociation and desensitization rate constants. 6. This study suggests that alcohols potentiate 5-HT3 receptor-mediated current by both increasing the rate of channel activation and stabilizing the open state by decreasing the rates of channel deactivation and desensitization.

Using the Monte Carlo method and physiologically based pharmacokinetic modeling, an occupational inhalation exposure to trichloroethylene consisting of 7 h of exposure per day for 5 days was simulated in populations of men and women of 5000 individuals each. The endpoint of concern for occupational exposure was drowsiness. The toxicologic condition leading to drowsiness was assumed to be high levels of both trichloroethanol and trichloroethylene. Therefore, the output of the simulation or dose metric was the maximum value of the sum of the concentration of trichloroethylene in blood and the concentration of trichloroethanol within its volume of distribution occurring within 1 week of exposure. The distributions of the dose metric in the simulated populations were lognormal. To protect 99% of a worker population, a concentration of 30 ppm over a 7-h period of the work day should not be exceeded. Subjecting a susceptible individual (the 99th percentile of the dose metric) to 200 ppm (the ACGIH short-term exposure limit or STEL) for 15 min twice a day over a work week necessitates a 2.5-h rest in fresh air following the STEL exposure to allow the blood concentrations of trichloroethylene and trichloroethanol to drop to levels that would not cause drowsiness. Both the OSHA PEL and the ACGIH TLV are greater than the value of 30 ppm derived here. As well as suggesting a new occupational guidance value, this study provides an example of this method of guidance value derivation.

A six-compartment physiologically based pharmacokinetic (PBPK) model for the B6C3F1 mouse was developed for trichloroethylene (TCE) and was linked with five metabolite submodels consisting of four compartments each. The PBPK model for TCE and the metabolite submodels described oral uptake and metabolism of TCE to chloral hydrate (CH). CH was further metabolized to trichloroethanol (TCOH) and trichloroacetic acid (TCA). TCA was excreted in urine and, to a lesser degree, metabolized to dichloroacetic acid (DCA). DCA was further metabolized. The majority of TCOH was glucuronidated (TCOG) and excreted in the urine and feces. TCOH was also excreted in urine or converted back to CH. Partition coefficient (PC) values for TCE were determined by vial equilibrium, and PC values for nonvolatile metabolites were determined by centrifugation. The largest PC values for TCE were the fat/blood (36.4) and the blood/air (15.9) values. Tissue/blood PC values for the water-soluble metabolites were low, with all PC values under 2.0. Mice were given bolus oral doses of 300, 600, 1200, and 2000 mg/kg TCE dissolved in corn oil. At various time points, mice were sacrificed, and blood, liver, lung, fat, and urine were collected and assayed for TCE and metabolites. The 1200 mg/kg dose group was used to calibrate the PBPK model for TCE and its metabolites. Urinary excretion rate constant values were 0. 06/hr/kg for CH, 1.14/hr/kg for TCOH, 32.8/hr/kg for TCOG, and 1. 55/hr/kg for TCA. A fecal excretion rate constant value for TCOG was 4.61/hr/kg. For oral bolus dosing of TCE with 300, 600, and 2000 mg/kg, model predictions of TCE and several metabolites were in general agreement with observations. This PBPK model for TCE and metabolites is the most comprehensive PBPK model constructed for P450-mediated metabolism of TCE in the B6C3F1 mouse.

but did in wild-type mice, suggesting the involvement of CYP2E1 in the metabolism from TCE to TCA. The constitutive expression of CYP2E1 in the liver of guinea pigs was greater in females than males. Conclusions: The sex difference in urinary TCA excretion after TRI and TCE treatments may be due to variation of the constitutive expression of CYP2E1. (J Occup Health 2013; 55: 443-449) Abstract: Sex Differences in Metabolism of Trichlo- roethylene and Trichloroethanol in Guinea Pigs: Yui HIBINO, et al. Department of Occupational and Envi- ronmental Health, Nagoya University Graduate School of Medicine—Objectives: Trichloroethylene (TRI) has the potential to cause generalized dermatitis complicated with hepatitis. The guinea pig maximization test (GPMT) also suggests that both TRI and its metab- olite trichloroethanol (TCE) exhibit immunogenicity and possible sex differences in guinea pigs. However, TRI and TCE metabolisms in guinea pigs have not been elucidated in detail. The first issue to clarify may be the sex differences in relation to the immunogenicity. Meth- ods: We collected urine from Hartley male and female guinea pigs 24 hours after intracutaneous injection of TRI, TCE or trichloroacetic acid (TCA) during a GPMT and measured the urinary metabolites by gas chroma- tography-mass spectrometry. Results: After TRI treat- ment, the amount of TCA was significantly greater in females than males, while there was no sex difference in the total amount (TCA + TCE). TCA was only detected in urine after TCA treatment. Interestingly, not only TCE but also TCA was detected in urine of both sexes after TCE treatment, and the amount of TCA was also greater in females than males. An additional experiment showed that TCE treatment did not result in the detection of urinary TCA in cytochrome P450 (CYP)2E1-null mice

Hydroxyethylation of 2-aminobenzothiazoles by ethylene chlorohydrin unexpectedly led to preferential formation of 3-β-chloroethylbenzothiazolin-2-one. In the case of unsubstituted 2-aminobenzothiazole, we also isolated the target 2-indno-3-β-hydroxyethylbenzothiazoline and bis((3-/3-hydroxyethyl)benzothiazolyl-2-indenelamnionium chloride. As a result of reaction of 2-aminobenzothiazole with 3-β-chloroethylbenzothiazolin-2-one, we obtained 2-(benzothiazolyl-2-imino)-3-(β-(2-oxobenzothiazolin-3-yl)ethyllbenzothiazoline. The structure ofthesynthesized compounds was established based on x-ray diffraction, PMR, IR, UV, and mass spectra.