Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.23.17 (PCE)
 1,301 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Male albino rats of the Donryu strain were divided into 4 groups: the normal control group, tetrachloromethane (CCl4, TCM) group, tetrachloroethylene (CCl2 = CCl2, PCE) group and trichloroethylene (CHCl = CCl2, TCE) group. Each group was consisted of 6 animals. TCM, PCE and TCE were administered orally at a dosage of 13 mmoles/kg as a 50% v/v olive oil solution to rats 24 hours prior to an oral administration of m-xylene (8.2 mmoles/kg as a 50% v/v olive oil solution). The normal control group was administered only olive oil (2.5 ml/kg) 24 hours prior to m-xylene dose. Urine was collected 24, 48, 72 and 96 hours after administration of m-xylene. The urine was analysed for m-methylhippuric acid (m-MHA) by the paper chromatographic method of Ogata et al. The results obtained were as follows: 1) Total urinary excretion of m-MHA in the normal control group was equivalent on a molar basis to about 58% of m-xylene received, and the major portions of the metabolites were excreted on the 1st day. 2) In TCM group, total urinary excretion of m-MHA was about a half of that in the normal control group. It was equivalent on a molar basis to about 30% of m-xylene received (p less than 0.01), and the urinary excretion of m-MHA on the 1st day was significantly less than those of the normal control group (p less than 0.001) and TCE group (p less than 0.05). 3) In PCE group, urinary excretion of m-MHA on the 1st day was significantly less than that of the normal control group (p less than 0.01) and the excretion was delayed. 4) In TCE group, total urinary excretion of m-MHA was slightly but not significantly less than that of the normal control group (p less than 0.05). 5) In TCM-ip group of rats which were given TCM orally 24 hours prior to the administration of m-xylene by intraperitoneal injection, urinary excretion of m-MHA on the 1st day and in 4 days after administration of m-xylene was less than that of the control-ip group.
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PMID:[Metabolism of m-xylene in rats after administration of chlorinated hydrocarbons (author's transl)]. 61 80

In compliance with the mandatory medical surveillance of workers exposed to tetrachloroethylene (PCE) in Italy, isoenzyme fractioning of serum gamma-glutamyltransferase (GGT) was performed on 141 workers of both sexes and on 130 control subjects. None of the workers showed any clinical symptoms of liver disease and their enzymatic profiles, including AST, ALT, 5'-NU, ALP, and GGT, were within the normal reference limits. A statistically significant increase in total GGT serum level was found in the exposed subjects, which was associated with an increase in one of the two fractions normally present in healthy individuals (GGT-2), as well as with the appearance and progressive increase of the level of a fraction (GGT-4) considered to be an expression of hepato-biliary impairment. Further research is ongoing among these workers, which will clarify whether or not electrophoretic GGT tests may be useful in detecting liver function changes due to occupational exposure to PCE.
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PMID:gamma-Glutamyltransferase isoenzyme pattern in workers exposed to tetrachloroethylene. 135 99

The effect of various doses (0.005-2.0 mg/kg b.w.) of vinblastine sulfate (VBL) was studied on the induction of micronuclei in polychromatic and normochromatic erythrocytes (PCE, NCE) of the bone marrow of female BALB/c mice. VBL treatment resulted in a dose-dependent increase in the frequency of micronucleated PCE and NCE, while the PCE/NCE ratio and mitotic index declined with increasing drug dose. The dose-effect curves were linear quadratic for all the parameters studied.
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PMID:Vinblastine treatment induces dose-dependent increases in the frequency of micronuclei in mouse bone marrow. 137 42

The effect of pretreatment with carboxymethylglucan (CMG) on the frequency of micronuclei induced by cyclophosphamide administration in mice was evaluated. Two doses of CMG (50 mg/kg body weight) injected either intraperitoneally 24 h or intravenously 1 h prior to two cyclophosphamide administrations (80 mg/kg) significantly decreased the frequency of micronucleated PCE in bone marrow. Of two evaluated derivatives of carboxymethylglucan, the K3 derivative was most efficient. The results show that it is possible to achieve a suppressive effect of soluble carboxymethylglucan prepared from Saccharomyces cerevisiae against cyclophosphamide mutagenicity. The notion may be useful for glucan's effects against pharmacocarcinogenesis. Therapeutic application of glucan with cyclophosphamide therapy may provide a remarkable decrease of the secondary tumour risk. The utilization of these results for human patients needs to be considered.
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PMID:Suppressing effects of glucan on micronuclei induced by cyclophosphamide in mice. 137 46

The present article reports the genotoxic potential of rapeseed oil cooking fume investigated by a battery of short-term tests (Ames test, SCE/V79 in vitro and mice micronucleus in vivo test). The results showed that the cooking fume contained mutagenic activity. In the presence of S9 mix, an increase in the number of the Salmonella TA98 was observed at doses ranging from 1.0 to 5.0 mg/plate, and the SCE frequencies of V79 cell were markedly raised at doses ranging from 0.05 to 0.5 mg.ml-1. The positive result was also obtained in mice micronucleus assay, the mice had inhaled the cooking fume a week earlier. The frequency of mice bone marrow MN-PCE was increased and it showed a remarkable time-dose-response relationship during the 4 weeks exposure. The results suggested that this cooking fume exposure may be a risk factor of lung cancer in Chinese women.
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PMID:A study on genotoxicity of cooking fumes from rapeseed oil. 144 58

A flow-cytometric assay is described that can be used to determine the frequency and the DNA content of micronucleated polychromatic (PCE) and normochromatic (NCE) erythrocytes in mouse peripheral blood. Thiazole orange was used for discrimination between PCEs and NCEs, while Hoechst 33342 was used to detect micronucleated PCEs and NCEs. Up to 70,000 polychromatic erythrocytes can be analyzed in less than 10 min. This corresponds to 150-3,000 micronucleated polychromatic erythrocytes, 90-95% of which are true events as determined with a fluorescence microscope after sorting. Using X-rays as the inducing agent in dose-response experiments, a significant increase can be registered at doses of 0.02 Gy. It seems possible that the method will also allow the detection of clastogenic effects of other inducing agents at lower doses than previously possible.
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PMID:Flow-cytometric enumeration of micronucleated polychromatic erythrocytes in mouse peripheral blood. 145 5

Ester hydrolysis represents an important biotransformation pathway for various parasympatholytic agents. Cleavage of the ciclotropium ester bond results in the formation of alpha-phenylciclopentylacetic acid (PCA). The relevance of this metabolic route for ciclotropium bromide (HIT-PCE, CAS 85166-20-7) including its stereochemical aspects was studied in a preliminary pharmacokinetic study. An enantiospecific assay for biological material was developed that is based on chiral derivatization of PCA with N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide (EDAC) and the primary amine S-FLOPA, a chiral coupling component for carboxylic acids derived from S-flunoxaprofen, followed by HPLC resolution. R-(--)-Ibuprofen was used as internal standard. From plasma or urine PCA can be extracted into n-hexane/ethanol (9:1) at pH 4 under addition of sodium chloride. Derivatization with EDAC/FLOPA was performed under addition of 1-hydroxybenzotriazole in anhydrous dichloromethane that contained trace amounts of pyridine (ambient temperature; 2 h reaction time). The chromatographic separation was performed on a silica gel stationary phase (Zorbax Sil) using n-hexane-chloroform-ethanol (100:10:1, by vol.) as mobile phase (flow rate, 2 ml/min; fluorescence-detection, 305/355 nm; elution order of the derivatives, (-) before (+)). Limit of quantification was 1.0 ng/ml for plasma and 10 ng/ml for urine. In the pharmacokinetic study in two healthy volunteers who received a single i.v. dose of 10 mg ciclotropium race-mate the PCA concentrations in plasma were below the detection limit, but approx. 1.5% of the administered dose were excreted into urine as the respective glucuronides.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Studies on the metabolic clearance of ciclotropium to alpha-phenylciclopentylacetic acid using a new enantiospecific metabolite assay. 149 51

Population risk to an environmental contaminant is represented as the product of a source term; the exposure function, which converts the source into a lifetime-equivalent contact rate in the population; the fraction metabolized; the toxic potency associated with the delivered dose; and the size of the exposed population. Using case studies for contamination of groundwater in California with tetrachloroethylene (PCE), the combined uncertainty in exposure and dose-response models is characterized. Three key issues are addressed: (a) uncertainty in quantifying pathway exposure factors that relate measured environmental concentrations to levels of contact in the exposed population; (b) the uncertainty in the human dose-response models derived from animal data; and (c) an overview of important contributors to the overall uncertainty in population risk estimates.
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PMID:Uncertainties in health-risk assessment: an integrated case study based on tetrachloroethylene in California groundwater. 155 16

Percutaneous absorption was measured in female hairless guinea pigs dermally exposed for 70 min to very dilute (approximately 10 to 100 ppb) aqueous solutions of 14C-labeled chloroform (CF), trichloroethylene (TCE), or tetrachloroethylene (PCE) in an airtight glass chamber containing no headspace. Similar experiments were conducted using aqueous solutions of TCE at 100,000 ppb. Dermal uptake was estimated by comparing the rate of radiolabel loss from chamber water in systems with and without experimental animals. After each low-concentration dermal-uptake experiment, radiolabel in total urine and feces excreted postexposure was measured and expressed as a fraction of corresponding estimated dermal uptake. For each of the compounds studied, the mean value of these fractions did not differ significantly from that obtained using animals injected with a known dose of that compound, indicating that our experimental system yielded accurate dermal-uptake estimates. The mean permeability coefficients obtained range from 0.13 cm/hr (CF) to 0.37 cm/hr (PCE); those obtained using low- vs high-concentration TCE are not significantly different. The value for CF is very close to one we calculate here from recently published data on CF uptake in human volunteers dermally exposed to aqueous CF while showering with normal tap water. Our results suggest that dermal absorption may be an important route of human exposure to chlorinated volatile organic compounds in domestic water supplies.
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PMID:Dermal absorption of dilute aqueous chloroform, trichloroethylene, and tetrachloroethylene in hairless guinea pigs. 160 Dec 7

Reductive dechlorination of tetrachloroethene (perchloroethylene; PCE) was observed at 20 degrees C in a fixed-bed column, filled with a mixture (3:1) of anaerobic sediment from the Rhine river and anaerobic granular sludge. In the presence of lactate (1 mM) as an electron donor, 9 microM PCE was dechlorinated to ethene. Ethene was further reduced to ethane. Mass balances demonstrated an almost complete conversion (95 to 98%), with no chlorinated compounds remaining (less than 0.5 micrograms/liter). When the temperature was lowered to 10 degrees C, an adaptation of 2 weeks was necessary to obtain the same performance as at 20 degrees C. Dechlorination by column material to ethene, followed by a slow ethane production, could also be achieved in batch cultures. Ethane was not formed in the presence of bromoethanesulfonic acid, an inhibitor of methanogenesis. The high dechlorination rate (3.7 mumol.l-1.h-1), even at low temperatures and considerable PCE concentrations, together with the absence of chlorinated end products, makes reductive dechlorination an attractive method for removal of PCE in bioremediation processes.
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PMID:Complete biological reductive transformation of tetrachloroethene to ethane. 162 77


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