Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Vinyl Compounds”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed2002

Biotransformation of L-cysteine S-conjugates and N-acetyl-L-cysteine S-conjugates of the sevoflurane degradation product fluoromethyl-2,2-difluoro-1-(trifluoromethyl)vinyl ether (compound A) in human kidney in vitro: interindividual variability in N-acetylation, N-deacetylation, and beta-lyase-catalyzed metabolism.

Fluoromethyl-2,2-difluoro-1-(trifluoromethyl)vinyl ether (FDVE; 1) is a fluoroalkene formed by the base-catalyzed degradation of the anesthetic sevoflurane. FDVE is nephrotoxic in rats. In both rats and humans, FDVE undergoes glutathione-dependent conjugation, cleavage to cysteine S-conjugates, and renal beta-lyase-catalyzed metabolism to reactive intermediates, which may cause nephrotoxicity. Interindividual variability in renal metabolism of FDVE is unknown. Therefore, this investigation quantified beta-lyase-catalyzed bioactivation and N-acetyltransferase-catalyzed inactivation of FDVE cysteine S-conjugates and reactivation of mercapturates by N-deacetylase in cytosol and microsomes from 20 human kidneys. In cytosol, N-acetylation ranged from 0.008 to 0.045 (0.024 +/- 0.01) nmol of mercapturate/mg/min and 0.001 to 0.07 (0.024 +/- 0.02) nmol of mercapturate/mg/min for alkane and alkene cysteine S-conjugates, respectively. Similar results for microsomal N-acetylation were obtained; N-acetylation ranged from 0.005 to 0.055 (0.025 +/- 0.02) nmol of mercapturate/mg/min and 0.001 to 0.06 (0.030 +/- 0.02) nmol of mercapturate/mg/min for alkane and alkene cysteine S-conjugates, respectively. Beta-lyase-catalyzed metabolism to pyruvate varied from 0.004 to 0.14 (0.051 +/- 0.04) nmol/mg/min and from 0.10 to 0.40 (0.26 +/- 0.08) nmol/mg/min for alkane and alkene cysteine-S-conjugates, respectively. N-deacetylation of mercapturates ranged from 0.8 to 2.5 (1.25 +/- 0.57) nmol of cysteine S-conjugate formed/mg/min and 0.05 to 0.37 (0.17 +/- 0.10) nmol of cysteine S-conjugate formed/mg/min for alkane and alkene FDVE mercapturates. Cytosolic cysteine S-conjugates metabolism by renal beta-lyase predominated over N-acetylation (ratio of activities was 0.2-6 and 3-146 for the alkane and alkene cysteine S-conjugates). N-deacetylation predominated over N-acetylation (ratio of activities was 20-205 and 2-54 for alkane and alkene S-conjugates). There was considerable (up to 50-fold) interindividual variability in rates of FDVE toxication (beta-lyase metabolism and N-deacetylation) and detoxication. This interindividual variability may effect individual susceptibility to the nephrotoxicity of FDVE and other haloalkenes.

Acetylation↗
PubMed1999

Dose-dependent metabolism of fluoromethyl-2,2-difluoro-1-(trifluoromethyl)vinyl ether (compound A), an anesthetic degradation product, to mercapturic acids and 3,3,3-trifluoro-2-(fluoromethoxy)propanoic acid in rats.

The volatile anesthetic sevoflurane is degraded in anesthesia machines to fluoromethyl-2,2-difluoro-1-(trifluoromethyl)vinyl ether (FDVE), to which humans are exposed. FDVE is metabolized in rats and humans to two alkane and two alkene glutathione S-conjugates that are hydrolyzed to the corresponding cysteine S-conjugates. The latter are N-acetylated to mercapturic acids, or bioactivated by renal cysteine conjugate beta-lyase to metabolites which may react with cellular macromolecules or hydrolyze to 3,3,3-trifluoro-2-(fluoromethoxy)propanoic acid. FDVE causes nephrotoxicity in rats, which evidence suggests is mediated by renal uptake of FDVE S-conjugates and metabolism by beta-lyase. Although pathways of FDVE metabolism have been described qualitatively, the purpose of this investigation was to quantify FDVE metabolism via mercapturic acid and beta-lyase pathways. Fischer 344 rats underwent 3-h nose-only exposure to FDVE (0 +/- 0, 46 +/- 19, 98 +/- 7, 150 +/- 29, and 220 +/- 40 ppm), and urine was collected for 24 h. Urine concentrations of the mercapturates, N-acetyl-S-(1,1,3,3, 3-pentafluoro-2-fluoromethoxypropyl)-L-cysteine and N-acetyl-S-(1-fluoro-2-fluoromethoxy-2-(trifluoromethyl)vinyl)-L- cysteine, the beta-lyase-dependent metabolite 3,3, 3-trifluoro-2-(fluoromethoxy)propanoic acid, and its degradation product trifluorolactic acid, were determined by GC/MS. There was dose-dependent urinary excretion of the alkane mercapturate N-acetyl-S-(1,1,3,3,3-pentafluoro-2-fluoromethoxypropyl)-L- cysteine and 3,3,3-trifluoro-2-(fluoromethoxy)propanoic acid, while excretion of the alkene mercapturate N-acetyl-S-(1-fluoro-2-fluoromethoxy-2-(trifluoromethyl)vinyl)-L- cysteine plateaued at higher FDVE exposures. The alkane:alkene mercapturic acid excretion ratio was between 2:1 and 4:1. Trifluorolactic acid was only rarely observed. Urine excretion of the beta-lyase-dependent metabolite 3,3, 3-trifluoro-2-(fluoromethoxy)propanoic acid was 10-fold greater than that of the combined mercapturates. Results show that FDVE cysteine S-conjugates undergo facile metabolism via renal beta-lyase, particularly in comparison with detoxication by mercapturic acid formation. The quantitative assay developed herein may provide a biomarker for FDVE exposure and relative metabolism via toxification and detoxifying pathways, applicable to animal and human investigations.

Acetylcysteine↗
PubMed2005

CuI-catalyzed intramolecular O-vinylation of carbonyl compounds.

The first copper-catalyzed intramolecular O-vinylation of carbonyl compounds with vinyl bromides was reported, among which the efficient formation of 5-, 6- and even 7-membered cyclic alkenyl ethers was achieved with beta-ketoesters as nucleophiles.

Catalysis↗
PubMed2001

Videographic assessment of the embolic characteristics of three polymeric compounds: ethylene vinyl alcohol, cellulose acetate, and liquid urethane.

BACKGROUND AND PURPOSE: Aneurysms have been clinically and experimentally treated with various surgical and endovascular methods, including endovascular polymer instillation. Additional tools may help to identify advantages and disadvantages of polymeric aneurysm treatment. We assessed the value of high-resolution videography to compare in vitro embolization characteristics of ethylene vinyl alcohol copolymer (VIN), cellulose acetate polymer (ACE), and urethane copolymer (UCO). METHODS: In a "neck-up" glass aneurysm model, solutions of 8% and 12% VIN, 8% and 12% ACE, and 8% UCO were introduced through a microcatheter into a xanthan gum solution at three flow rates: full physiological (62 cm/s), half physiological, and flow arrest. Each formulation was then introduced into a "neck-down" aneurysm model at flow arrest, for a total of 20 experiments. Results were tabulated for six different categories: outflow tail formation, inflow-zone polymer-mass deformation, inflow-zone migration, detachment tail formation, adherent mass pullout, and conjectural net effect. RESULTS: Of the 20 experiments, nine had unacceptable results because of potential clinical complications. The results were unacceptable in four of eight VIN experiments, four of eight ACE experiments, and one of four UCO experiments. VIN performance was more dependent on flow arrest than the more viscous ACE. The growth of the ACE solutions was most circumferential, with balloonlike growth characteristics, little inflow-zone effects, and fewer outflow tails than seen with VIN. All compounds had the potential for partial catheter adhesion and catheter-adhesing tails. UCO had the highest percentage of favorable results and the lowest percentage of unfavorable results. CONCLUSION: Videographic analysis allows detailed assessment of the dynamic embolization characteristics of polymers, revealing potential advantages of compounds such as UCO.

Cellulose↗
PubMed1981

Review of experimental carcinogenesis by compounds related to vinyl chloride.

The experimental carcinogenesis results in six compounds related to vinyl chloride are reported. Vinylidene chloride, given by inhalation, was carcinogenic in male CD-1 mice, male CD rats, Sprague-Dawley rats and male Swiss mice. Trichloroethylene, given by gavage and inhalation, was carcinogenic in the B6C3F1 mice. When given by gavage, perchloroethylene was carcinogenic in the B6C3F1 mice, and dichloroethane was carcinogenic in Osborne-Mendel rats and B6C3F1 mice. Dibromoethane, given by gavage and inhalation, was carcinogenic in B6C3F1 mice, F344 rats and Osborne-Mendel rats. Finally, epichlorohydrin was carcinogenic in male Sprague-Dawley rats and B6C3F1 mice.

Aerosols↗
PubMed1980

Vinyl chloride: an example for evaluating mutagenic effects in mammals in vivo after exposure to inhalation.

As part of a programme of investigations on the mutagenic effects in mammals in vivo after inhalation of environmental chemicals, the effects of the industrial compound vinyl chloride (VC) was analysed. Chinese hamsters were exposed to 1.25%, 2.5% or 5% (v/v) VC in air for 6, 12 or 24 hr. Bone marrow chromosomes were analysed for induced chromosome aberrations and sister-chromatid exchanges (SCEs) 26 h after beginning of exposure. The frequency of VC-induced chromosome aberrations and SCEs both depend on dose and length of exposure. The highest measured effects were 33.25 SCEs/ cell after an exposure to 2.5% VC for 24 h and 25.7% metaphases with aberrations, when exposed to 5% VC for 24 h.

Animals↗
PubMed2002

Physiologically based pharmacokinetic (PBPK) models for nasal tissue dosimetry of organic esters: assessing the state-of-knowledge and risk assessment applications with methyl methacrylate and vinyl acetate.

Mathematical models have been developed to describe nasal epithelial tissue dosimetry with two compounds, vinyl acetate (VA) and methyl methacrylate (MMA), that cause toxicity in these tissues These models couple computational fluid dynamics (CFD) calculations that map airflow patterns within the nose with physiologically based pharmacokinetic (PBPK) models that integrate diffusion, metabolism, and tissue interactions of these compounds. Dose metrics estimated in these models for MMA and VA, respectively, were rates of MMA metabolism per volume of tissue and alterations in pH in target tissues associated with VA hydrolysis and metabolism. In this article, four scientists who have contributed significantly to development of these models describe the many similarities and relatively few differences between the MMA and VA models. Some differences arise naturally because of differences in target tissues, in the calculated measures of tissue dose, and in the modes of action for highly extracted vapors (VA) compared with poorly extracted vapors (MMA). A difference in the approach used to estimate metabolic parameters from human tissues provides insights into interindividual extrapolation and identifies opportunities for studies with human nasal tissues to enhance current risk assessments. In general, the differences in model structure for these two esters were essential for describing the biology of the observed responses and in accounting for the different measures of target tissue dose. This article is intended to serve as a guide for understanding issues of optimum model structure and optimal data sources for these nasal tissue dosimetry models. We also hope that it leads to greater international acceptance of these hybrid CFD/PBPK modeling approaches for improving risk assessment for many nasal toxicants. In general, these models predict either equivalent (VA) or lower (MMA) nasal tissue doses in humans compared with tissue doses at equivalent exposure concentrations in rats.

Air Movements↗
PubMed1971

Chemical wastes in the sea: new forms of marine pollution.

Drums containing chemical wastes have been found in and along the North Sea. The wastes were analyzed and were found to include lower chlorinated aliphatic compounds, vinyl esters, chlorinated aromatic amines and nitrocompounds, and the insecticide endosulfan. Because dropping these drums into the sea endangers the environment and results in damage to fishing operations, measures should be taken to stop this practice.

Acetates↗
PubMed1986

Vinyl acetate, a structural analog of vinyl carbamate, fails to induce enzyme-altered foci in rat liver.

The development of hepatic enzyme-altered foci (ATPase, GGTase) was investigated after dosing vinyl acetate (200 and 400 mg/kg per day, orally) to newborn rats for 3 weeks, with or without subsequent promotion by phenobarbital. Whereas the structurally related compounds vinyl carbamate and vinyl chloride induce enzyme-altered foci under comparable experimental conditions, no foci were observed in vinyl acetate-treated animals at the age of 14 weeks. This is consistent with investigations on metabolism and pharmacokinetics of vinyl acetate which show that this compound, after entering the organism, is immediately split by blood esterases and thus may not be available for epoxidation to an ultimately carcinogenic metabolite.

Adenosine Triphosphatases↗
PubMed1977

Comparison of wool reactions with selected mono and bifunctional reagents.

The molecular structure of wool is discussed in relation to chemical reactivity and the role of disulfide crosslinks. Ideal characteristics of an effective medium (e.g. dimethylformamide) for modifying wool include the ability to penetrate and swell wool without interfering with reagents used. The extent of reaction of wool or reduced wool is compared for mono-and bifunctional activated vinyl compounds, isocyanates, acid chlorides, acid anhydrides, sulfonyl chlorides, and alkyl halides. The degree of crosslinking is assessed by solubility, supercontraction, and tensile tests. Optical and electron scanning microscopy can give evidence of external polymer deposition in contrast to internal chemical modification. Effects of crosslinking by bifunctional reagents are related to changes in mechanical, chemical, and biological (moth-resisting) properties of the modified wool.

Animals↗