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1.
J Occup Health ; 62(1): e12142, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32799435

RESUMO

OBJECTIVES: Occupational exposure to trichloroethylene (TCE) induces trichloroethylene hypersensitivity syndrome (TCEHS), which causes hypersensitivity dermatitis and hepatitis. However, whether TCE itself or its two metabolites, trichloroethanol (TCEOH) and trichloroacetic acid (TCA), are involved in TCEHS remains unclear. Therefore, in this study we explored the allergens causing TCEHS and characterized TCEHS-related liver injury in guinea pigs. METHOD: The guinea pig maximization test was performed using TCE, TCEOH, and TCA as candidate allergens. Skin inflammation was scored, and liver function and histopathological changes were evaluated by biochemical tests and hematoxylin and eosin staining, respectively. RESULTS: The sensitization rates for TCE, TCEOH, and TCA were 90.0%, 50.0%, and 0.0%, respectively. In the TCE and TCEOH experimental groups, the skin showed varying degrees of erythema with eosinophil granulocyte infiltration in the dermis. Additionally, serum alanine aminotransferase and γ-glutamyl transpeptidase levels increased significantly, and histological analysis revealed focal hepatocellular necrosis with inflammatory cell infiltration in the liver. CONCLUSIONS: TCE is the main cause of allergy and TCEOH is a secondary factor for allergy in guinea pigs. TCE and TCEOH can cause immune-mediated skin sensitization complicated by focal hepatic necrosis.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas/etiologia , Etilenocloroidrina/análogos & derivados , Necrose/induzido quimicamente , Dermatopatias/induzido quimicamente , Ácido Tricloroacético/toxicidade , Tricloroetileno/toxicidade , Animais , Etilenocloroidrina/toxicidade , Feminino , Cobaias , Hipersensibilidade/etiologia , Exposição Ocupacional
2.
Environ Sci Process Impacts ; 22(3): 719-727, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31970349

RESUMO

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.


Assuntos
Cloro , Etilenocloroidrina/análogos & derivados , Radical Hidroxila , Atmosfera , Etilenocloroidrina/química , Cinética
3.
Sci Rep ; 9(1): 13923, 2019 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-31558752

RESUMO

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.


Assuntos
Eletroforese em Gel de Poliacrilamida/métodos , Etilenocloroidrina/análogos & derivados , Proteômica/métodos , Raios Ultravioleta , Absorção de Radiação , Etilenocloroidrina/química , Proteínas/química , Triptofano/química , Tirosina/química
4.
Sci Rep ; 9(1): 9294, 2019 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-31243319

RESUMO

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.


Assuntos
Cromatografia Líquida/métodos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Organofosfatos/sangue , Espectrometria de Massas em Tandem/métodos , Pré-Escolar , Hidrato de Cloral/sangue , Etilenocloroidrina/análogos & derivados , Etilenocloroidrina/sangue , Feminino , Humanos , Hidrólise , Hipnóticos e Sedativos/sangue , Lactente , Japão , Limite de Detecção , Masculino , Espectrometria de Massas , Reprodutibilidade dos Testes , Ácido Tricloroacético/sangue
5.
Sci Rep ; 9(1): 873, 2019 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-30696868

RESUMO

Because of its association with severe gastric pathologies, including gastric cancer, Helicobacter pylori has been subject of research for more than 30 years. Its capacity to adapt and survive in the human stomach can be attributed to its genetic flexibility. Its natural competence and its capacity to turn genes on and off allows H. pylori to adapt rapidly to the changing conditions of its host. Because of its genetic variability, it is difficult to establish the uniqueness of each strain obtained from a human host. The methods considered to-date to deliver the best result for differentiation of strains are Rapid Amplification of Polymorphic DNA (RAPD), Multilocus Sequence Typing (MLST) and Whole Genome Sequencing (WGS) analysis. While RAPD analysis is cost-effective, it requires a stable genome for its reliability. MLST and WGS are optimal for strain identification, however, they require analysis of data at the bioinformatics level. Using the StainFree method, which modifies tryptophan residues on proteins using 2, 2, 2, - trichloroethanol (TCE), we observed a strain specific pattern of tryptophan in 1D acrylamide gels. In order to establish the effectiveness of tryptophan fingerprinting for strain identification, we compared the graphic analysis of tryptophan-labelled bands in the gel images with MLST results. Based on this, we find that tryptophan banding patterns can be used as an alternative method for the differentiation of H. pylori strains. Furthermore, investigating the origin for these differences, we found that H. pylori strains alters the number and/or position of tryptophan present in several proteins at the genetic code level, with most exchanges taking place in membrane- and cation-binding proteins, which could be part of a novel response of H. pylori to host adaptation.


Assuntos
Helicobacter pylori/genética , Helicobacter pylori/metabolismo , Triptofano/metabolismo , DNA Bacteriano/genética , Etilenocloroidrina/análogos & derivados , Genoma Bacteriano/genética , Genótipo , Infecções por Helicobacter/genética , Humanos , Tipagem de Sequências Multilocus/métodos , Técnica de Amplificação ao Acaso de DNA Polimórfico/métodos , Reprodutibilidade dos Testes , Análise de Sequência de DNA/métodos , Neoplasias Gástricas/genética
6.
Methods Mol Biol ; 1853: 179-190, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30097944

RESUMO

SDS-polyacrylamide gel electrophoresis (SDS-PAGE) is one of the essential techniques in molecular biology and biochemistry laboratories and requires rapid visualization methods for efficient sample analysis. Proteins on polyacrylamide gels can be visualized within 5 min via the photoreaction of tryptophan with trichloroethanol. This process does not require protein fixation, staining, or destaining. In this method polyacrylamide gels are prepared by adding trichloroethanol before polymerization. After electrophoresis, the gel is immediately activated on a standard UV transilluminator and the fluorescently labeled proteins are imaged. The reaction is based on the photoreaction of trichloroethanol with tryptophan residues within the protein. This generates a visible blue-green fluorescence (∼500 nm) that is accurately imaged. Here we describe the preparation of Tris-glycine and Tris-tricine SDS-polyacrylamide gels with trichloroethanol and the photoreaction and visualization of tryptophan containing proteins.


Assuntos
Eletroforese em Gel de Poliacrilamida , Etilenocloroidrina/análogos & derivados , Proteínas Luminescentes , Fotoquímica , Triptofano , Eletroforese em Gel de Poliacrilamida/métodos , Etilenocloroidrina/química , Proteínas Luminescentes/análise , Proteínas Luminescentes/química , Fotoquímica/métodos , Triptofano/química
7.
Acta Crystallogr F Struct Biol Commun ; 74(Pt 5): 307-314, 2018 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-29717999

RESUMO

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.


Assuntos
Etilenocloroidrina/análogos & derivados , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Etilenocloroidrina/metabolismo , Microscopia de Fluorescência/métodos , Estrutura Secundária de Proteína
8.
J Biomol Struct Dyn ; 36(3): 551-560, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28150569

RESUMO

Catalase, a ubiquitous enzyme of the free radical scavenging machinery unfolds and aggregates in the presence of 2,2,2-triflouroethanol (TFE). Catalase molecule aggregates at 50% TFE as evident by high thioflavin T fluorescence, shifted congo red absorbance, change in circular dichroism and soret spectra. TEM images confirmed the nature of catalase aggregates to be oligomers. Organic solvent-induced aggregation of catalase is prevented by the presence of peroxidase (another enzyme of the free radical scavenging machinery). To alter the progress of aggregation in presence of increasing concentration of TFE, we determined the effect of peroxidase on catalase oligomerization by several different techniques, including turbidity measurement, activity assay, thioflavin T fluorescence, circular dichroism, shift in congo red absorbance, transmission electron microscopy (TEM), Rayleigh scattering, soret absorption spectra, and ANS fluorescence. The presence of peroxidase in the vicinity of folded catalase helps it to remain functionally active and inhibited aggregation in the presence of TFE, suggesting that proteins are stable in crowded environments. Moreover, this catalase-peroxidase interaction is biologically significant as it provides insights into how the aggregation process may be altered.


Assuntos
Catalase/química , Peroxidase/química , Agregados Proteicos/efeitos dos fármacos , Multimerização Proteica/efeitos dos fármacos , Dicroísmo Circular , Vermelho Congo , Etilenocloroidrina/análogos & derivados , Etilenocloroidrina/química , Sequestradores de Radicais Livres/química , Ligação Proteica , Conformação Proteica/efeitos dos fármacos , Desnaturação Proteica , Dobramento de Proteína , Espectrometria de Fluorescência
9.
Anal Biochem ; 521: 8-10, 2017 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-28069453

RESUMO

Gelatinase zymography is a commonly used laboratory procedure; however, variability in sample loading and concentration reduce the accuracy of quantitative results obtained from this technique. To facilitate normalization of gelatinase activity by loaded protein amount, we developed a protocol using the trihalocompound 2,2,2-trichloroethanol to allow for gelatin zymography and total protein labeling within the same gel. We showed that detected protein levels increased linearly with loading, and describe a loading concentration range over which normalized gelatinase activity was constant. We conclude that in-gel total protein detection is feasible in gelatin zymography and greatly improves comparison of gelatinase activity between samples.


Assuntos
Eletroforese em Gel de Poliacrilamida/normas , Fibrossarcoma/enzimologia , Gelatina/metabolismo , Gelatinases/metabolismo , Metaloproteinases da Matriz/análise , Etilenocloroidrina/análogos & derivados , Etilenocloroidrina/metabolismo , Humanos , Metaloproteinases da Matriz/metabolismo , Células Tumorais Cultivadas
10.
Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi ; 35(10): 780-782, 2017 Oct 20.
Artigo em Chinês | MEDLINE | ID: mdl-29294559

RESUMO

Objective: To establish a method for determing the trichloroethylene(TCE)and trichloroethanol(TCOH)in blood samples by liquid-liquid extraction-gas chromatography with electron capture detector. Methods: With this method,ether was used as extraction solvent and trichloromethane was used as an internal standard. The whole blood sample was extracted with ether, and dehydrated by anhydrous sodium sulfate. Then the analytes were separated on HP-5 capillary column(30m×0.32mm×0.15µm)and detected byECD.The retention time was for qualitative analysis and the internal standard was for quantitation. Results: The standard curves of TCE and TCOH showed significant linearity between 95.5µg/L-7640.0µg/L(r=0.9997)and 19.0µg/L-1520.0µg/L(r=0.9992). The average recovery was 95.5%-103.6%.The intra-day and inter-day precisions(RSD)were 2.5%-6.8%(n=6)and 1.6%-4.3%(n=6) respectively. The detect limit of TCE and TCOH were 2.10 µg/L and 0.56µg/L(S/N=3)respectively.The blood can be kept 7 days at-20℃ refrigerator without significantly loss. Conclusion: This method is proved to be simple,practical and highly sensitive. It can satisfy the request for the determination of blood samples of humans exposed to TCE.


Assuntos
Cromatografia Gasosa/métodos , Etilenocloroidrina/análogos & derivados , Extração Líquido-Líquido/métodos , Tricloroetileno/sangue , Etilenocloroidrina/sangue , Humanos
11.
Biochem Mol Biol Educ ; 43(5): 358-65, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26153352

RESUMO

SDS-PAGE and western blotting are two commonly taught protein detection techniques in biochemistry and molecular biology laboratory classrooms. A pitfall associated with incorporating these techniques into the laboratory is the significant wait times that do not allow students to obtain timely results. The waiting associated with SDS-PAGE comes from staining and destaining, whereas with western blotting it is the times required for antibody incubations and the numerous wash steps. This laboratory exercise incorporates 2,2,2-trichloroethanol (TCE) into the SDS-PAGE gel allowing for visualization of migrated proteins in a matter of minutes, saving both the time and chemical waste associated with traditional Coomassie staining. Additionally, TCE staining does not affect protein transfer eliminating the requirement for duplicated gels for total protein and western analyses. Protein transfer can be confirmed immediately without the use of Ponceau S staining. Lastly, this western blot procedure has been further shortened by using an HRP-conjugated primary antibody, which eliminates the secondary antibody incubation and washes, and uses a colorimetric detection to allow for visualization by students without the need for specialized equipment.


Assuntos
Western Blotting/métodos , Educação/métodos , Biologia Molecular/educação , Currículo , Eletroforese em Gel de Poliacrilamida/métodos , Etilenocloroidrina/análogos & derivados , Etilenocloroidrina/química , Peroxidase do Rábano Silvestre/química , Humanos , Laboratórios , Biologia Molecular/métodos , Estudantes , Universidades
12.
J Toxicol Environ Health A ; 78(11): 671-84, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26039745

RESUMO

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.


Assuntos
Etilenocloroidrina/análogos & derivados , Naproxeno/metabolismo , Ácido Salicílico/metabolismo , Solventes/metabolismo , Ácido Tricloroacético/metabolismo , Tricloroetileno/metabolismo , Ácido Valproico/metabolismo , Analgésicos/metabolismo , Animais , Anti-Inflamatórios não Esteroides/metabolismo , Anticonvulsivantes/metabolismo , Etilenocloroidrina/sangue , Etilenocloroidrina/metabolismo , Etilenocloroidrina/farmacocinética , Etilenocloroidrina/urina , Masculino , Modelos Teóricos , Ratos , Ratos Sprague-Dawley , Medição de Risco , Solventes/farmacocinética , Ácido Tricloroacético/sangue , Ácido Tricloroacético/farmacocinética , Ácido Tricloroacético/urina , Tricloroetileno/sangue , Tricloroetileno/farmacocinética , Tricloroetileno/urina
13.
Org Lett ; 17(10): 2396-9, 2015 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-25941891

RESUMO

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.


Assuntos
Ácidos Borônicos/química , Etilenocloroidrina/análogos & derivados , Tetra-Hidroisoquinolinas/química , Trifluoretanol/química , Catálise , Etilenocloroidrina/química , Estrutura Molecular , Estereoisomerismo
14.
Biochem Biophys Res Commun ; 462(3): 239-44, 2015 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-25956065

RESUMO

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.


Assuntos
Fatores de Transcrição ARNTL/genética , Ritmo Circadiano/efeitos dos fármacos , Ritmo Circadiano/genética , Etilenocloroidrina/análogos & derivados , Animais , Proteínas CLOCK/genética , Linhagem Celular , Hidrato de Cloral/farmacologia , Hidrato de Cloral/toxicidade , Etilenocloroidrina/farmacologia , Etilenocloroidrina/toxicidade , Humanos , Hipnóticos e Sedativos/farmacologia , Hipnóticos e Sedativos/toxicidade , Medições Luminescentes , Masculino , Camundongos , Membro 1 do Grupo D da Subfamília 1 de Receptores Nucleares/genética , Proteínas Circadianas Period/genética , Ratos , Ratos Endogâmicos F344
15.
Phys Med Biol ; 60(12): 4685-704, 2015 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-26020119

RESUMO

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 for >120 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.


Assuntos
Géis/química , Violeta Genciana/química , Imagens de Fantasmas , Radiometria/métodos , Radiometria/normas , Tensoativos/química , Água/química , Cetrimônio , Compostos de Cetrimônio/química , Relação Dose-Resposta à Radiação , Etilenocloroidrina/análogos & derivados , Etilenocloroidrina/química , Micelas
16.
Phys Med Biol ; 60(12): 4665-83, 2015 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-26020840

RESUMO

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.


Assuntos
Géis/química , Violeta Genciana/química , Radiometria/métodos , Corantes de Rosanilina/química , Tensoativos/química , Cetrimônio , Compostos de Cetrimônio/química , Relação Dose-Resposta à Radiação , Etilenocloroidrina/análogos & derivados , Etilenocloroidrina/química , Concentração de Íons de Hidrogênio , Micelas , Octoxinol/química , Ácido Tricloroacético/química
17.
J Toxicol Environ Health A ; 78(1): 15-31, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25424544

RESUMO

Trichloroethylene (TCE) is a widely used organic solvent. Although TCE is classified as carcinogenic to humans, substantial gaps remain in our understanding of interindividual variability in TCE metabolism and toxicity, especially in the liver. A hypothesis was tested that amounts of oxidative metabolites of TCE in mouse liver are associated with hepatic-specific toxicity. Oral dosing with TCE was conducted in subacute (600 mg/kg/d; 5 d; 7 inbred mouse strains) and subchronic (100 or 400 mg/kg/d; 1, 2, or 4 wk; 2 inbred mouse strains) designs. The quantitative relationship was evaluated between strain-, dose-, and time-dependent formation of TCE metabolites from cytochrome P-450-mediated oxidation (trichloroacetic acid [TCA], dichloroacetic acid [DCA], and trichloroethanol) and glutathione conjugation [S-(1,2-dichlorovinyl)-L-cysteine and S-(1,2-dichlorovinyl)glutathione] in serum and liver, and various hepatic toxicity phenotypes. In subacute study, interstrain variability in TCE metabolite amounts was observed in serum and liver. No marked induction of Cyp2e1 protein levels in liver was detected. Serum and hepatic levels of TCA and DCA were correlated with increased transcription of peroxisome proliferator-marker genes Cyp4a10 and Acox1 but not with degree of induction in hepatocellular proliferation. In subchronic study, serum and liver levels of oxidative metabolites gradually decreased over time despite continuous dosing. Hepatic protein levels of CYP2E1, ADH, and ALDH2 were unaffected by treatment with TCE. While the magnitude of induction of peroxisome proliferator-marker genes also declined, hepatocellular proliferation increased. This study offers a unique opportunity to provide a scientific data-driven rationale for some of the major assumptions in human health assessment of TCE.


Assuntos
Fígado/efeitos dos fármacos , Tricloroetileno/farmacocinética , Tricloroetileno/toxicidade , Administração Oral , Animais , Carcinógenos/farmacocinética , Carcinógenos/toxicidade , Proliferação de Células , Cisteína/análogos & derivados , Cisteína/sangue , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Ácido Dicloroacético/sangue , Relação Dose-Resposta a Droga , Etilenocloroidrina/análogos & derivados , Etilenocloroidrina/metabolismo , Expressão Gênica , Glutationa/análogos & derivados , Glutationa/sangue , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Fígado/citologia , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos , Oxirredução/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Reação em Cadeia da Polimerase em Tempo Real , Solventes/farmacocinética , Solventes/toxicidade , Ácido Tricloroacético/sangue
18.
J Toxicol Environ Health A ; 78(1): 32-49, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25424545

RESUMO

Trichloroethylene (TCE) is a well-known environmental and occupational toxicant that is classified as carcinogenic to humans based on the epidemiological evidence of an association with higher risk of renal-cell carcinoma. A number of scientific issues critical for assessing human health risks from TCE remain unresolved, such as the amount of kidney-toxic glutathione conjugation metabolites formed, interspecies and interindividual differences, and the mode of action for kidney carcinogenicity. It was postulated that TCE renal metabolite levels are associated with kidney-specific toxicity. Oral dosing with TCE was conducted in subacute (600 mg/kg/d; 5 d; 7 inbred mouse strains) and subchronic (100 or 400 mg/kg/d; 1, 2, or 4 wk; 2 inbred mouse strains) designs. The quantitative relationship was evaluated between strain-, dose, and time-dependent formation of TCE metabolites from cytochrome P-450-mediated oxidation (trichloroacetic acid [TCA], dichloroacetic acid [DCA], and trichloroethanol) and glutathione conjugation [S-(1,2-dichlorovinyl)-L-cysteine and S-(1,2-dichlorovinyl)glutathione], and various kidney toxicity phenotypes. In subacute study, interstrain differences in renal TCE metabolite levels were observed. In addition, data showed that in several strains kidney-specific effects of TCE included induction of peroxisome proliferator-marker genes Cyp4a10 and Acox1, increased cell proliferation, and expression of KIM-1, a marker of tubular damage and regeneration. In subchronic study, peroxisome proliferator-marker gene induction and renal toxicity diminished while cell proliferative response was elevated in a dose-dependent manner in NZW/LacJ but not C57BL/6J mice. Overall, data demonstrated that renal TCE metabolite levels are associated with kidney-specific toxicity and that these effects are strain dependent.


Assuntos
Rim/efeitos dos fármacos , Tricloroetileno/farmacocinética , Tricloroetileno/toxicidade , Animais , Carcinógenos/farmacocinética , Carcinógenos/toxicidade , Proliferação de Células/efeitos dos fármacos , Cisteína/análogos & derivados , Cisteína/metabolismo , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Ácido Dicloroacético/metabolismo , Etilenocloroidrina/análogos & derivados , Etilenocloroidrina/metabolismo , Glutationa/análogos & derivados , Glutationa/metabolismo , Receptor Celular 1 do Vírus da Hepatite A , Rim/citologia , Rim/metabolismo , Masculino , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos , Oxirredução/efeitos dos fármacos , PPAR alfa/genética , PPAR alfa/metabolismo , Ácido Tricloroacético/metabolismo
19.
Toxicology ; 323: 70-7, 2014 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-24923549

RESUMO

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 ß-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 (500mg/kg/day) or TCE-OH at (100mg/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.


Assuntos
Etilenocloroidrina/análogos & derivados , Formiatos/urina , Rim/efeitos dos fármacos , Solventes/toxicidade , Tricloroetileno/toxicidade , 5-Metiltetra-Hidrofolato-Homocisteína S-Metiltransferase/metabolismo , Acetilglucosaminidase/urina , Animais , Moléculas de Adesão Celular/urina , Etilenocloroidrina/toxicidade , Rim/patologia , Fígado/efeitos dos fármacos , Fígado/enzimologia , Fígado/patologia , Masculino , Ácido Metilmalônico/urina , Tamanho do Órgão/efeitos dos fármacos , Ratos , Ratos Endogâmicos F344 , Testes de Toxicidade Subcrônica
20.
Photochem Photobiol ; 90(5): 1027-33, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24738707

RESUMO

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.


Assuntos
Corantes Fluorescentes/química , Iminas/química , Indóis/química , Triptofano/análogos & derivados , Triptofano/química , Acetamidas/química , Cloroacetatos/química , Clorofórmio/química , Etilenocloroidrina/análogos & derivados , Etilenocloroidrina/química , Luz , Espectroscopia de Ressonância Magnética , Peso Molecular , Processos Fotoquímicos , Coloração e Rotulagem/métodos , Trialometanos/química
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