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1

Comparison of ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEEs) concentrations in hair for testing abstinence  

Microsoft Academic Search

Hair analysis is a powerful tool for retrospective drug analysis. By determining the minor ethanol metabolites ethyl glucuronide\\u000a (EtG) and fatty acid ethyl esters (FAEEs) in hair, even a previous consumption of alcohol is detectable. However, previous\\u000a studies showed a lack of correlation if both parameters are determined simultaneously. A further study was conducted to confirm\\u000a or refute these results.

M. E. Albermann; F. Musshoff; B. Madea

2011-01-01

2

Ethyl glucuronide  

Microsoft Academic Search

A marker with a specific time spectrum of detection and both high sensitivity and specificity is required to diminish the clinically as well as forensically important gap on the time axis between short- and long-term markers of alcohol consumption like ethanol and CDT, GGT or MCV, respectively. Ethyl glucuronide (EtG) is a non-volatile, water-soluble, stable upon storage, direct metabolite of

Friedrich Martin Wurst; Christoph Kempter; Joerg Metzger; Stephan Seidl; Andreas Alt

2000-01-01

3

Detecting alcohol abuse: traditional blood alcohol markers compared to ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEEs) measurement in hair.  

PubMed

Alcohol abuse is a common problem in society; however, the technical capabilities of evaluating individual alcohol consumption using objective biomarkers are rather limited at present. In recent years research has focused on alcohol markers using hair analysis but data on performance and reliable cut-off values are still lacking. In this study 169 candidates were tested to compare traditional biomarkers, such as carbohydrate-deficient-transferrin (CDT), gamma glutamyl transferase (GGT), aspartate amino transferase, alanine amino transferase and the mean corpuscular volume of the erythrocytes, with alcohol markers detectable in hair such as ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEEs). This study revealed that EtG, GGT and CDT showed the best results, demonstrating areas under the curve calculated from receiver operating characteristics of 0.941, 0.943 and 0.899 respectively. The lowest false-negative and false-positive rates were obtained by using a combined interpretation system for hair EtG and FAEEs. All markers demonstrated only low to moderate correlations. Optimum cut-off values for differentiation between social and chronic excessive drinking calculated for hair EtG and FAEEs were 28 pg/mg and 0.675 ng/mg, respectively. The critical values published in the "Consensus on Alcohol Markers 2012" by the Society of Hair Testing were confirmed. PMID:23504201

Hastedt, Martin; Büchner, Mara; Rothe, Michael; Gapert, René; Herre, Sieglinde; Krumbiegel, Franziska; Tsokos, Michael; Kienast, Thorsten; Heinz, Andreas; Hartwig, Sven

2013-03-17

4

An evaluation of the DRI-ETG EIA method for the determination of ethyl glucuronide concentrations in clinical and post-mortem urine.  

PubMed

A commercial enzyme immunoassay for the qualitative and semi-quantitative measurement of ethyl glucuronide (EtG) in urine was evaluated. Post-mortem (n=800), and clinical urine (n=200) samples were assayed using a Hitachi 902 analyzer. The determined concentrations were compared with those obtained using a previously published liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of EtG and ethyl sulfate. Using a cut-off of 0.5?µg/ml and LC-MS/MS limit of reporting of 0.1?µg/ml, there was a sensitivity of 60.8% and a specificity of 100% for clinical samples. For post-mortem samples, sensitivity and specificity were 82.4% and 97.1%, respectively. When reducing the cut-off to 0.1?µg/ml, the sensitivity and specificity were 83.3% and 100% for clinical samples whereas for post-mortem samples the sensitivity and specificity were 90.3 % and 88.3 %, respectively. The best trade-offs between sensitivity and specificity for LC-MS/MS limits of reporting of 0.5 and 0.1?µg/ml were achieved when using immunoassay cut-offs of 0.3 and 0.092?µg/ml, respectively. There was good correlation between quantitative results obtained by both methods but analysis of samples by LC-MS/MS gave higher concentrations than by enzyme immunoassay (EIA), with a statistically significant proportional bias (P<0.0001, Deming regression) for both sample types. The immunoassay is reliable for the qualitative and semi-quantitative presumptive detection of ethyl glucuronide in urine. PMID:22374825

Turfus, Sophie C; Vo, Tu; Niehaus, Nadia; Gerostamoulos, Dimitri; Beyer, Jochen

2012-02-28

5

Disappearance of ethyl glucuronide during heavy putrefaction  

Microsoft Academic Search

IntroductionThere are previous publications showing the use of ethyl glucuronide (EtG), a non-oxidative metabolite of ethanol, as a marker of ante-mortem ingestion of alcohol in forensic autopsy cases. The problem of possible degradation or formation of EtG during putrefaction is however not well studied and the aim of this study was to investigate the possibility of false negative and false

Gudrun Høiseth; Ritva Karinen; Lene Johnsen; Per Trygve Normann; Asbjørg S. Christophersen; Jørg Mørland

2008-01-01

6

Detection of ethyl glucuronide in blood spotted on different surfaces  

Microsoft Academic Search

This study aims to show that sensitive detection of ethyl glucuronide in dried blood spotted onto various surfaces after a period of 24h is feasible. At present, there is insufficient information how tightly ethyl glucuronide (EtG) binds to various materials and how easily it can be eluted. 4ml aliquots of blood samples obtained from seven volunteers after consumption of alcoholic

M. Winkler; E. Kaufmann; D. Thoma; A. Thierauf; W. Weinmann; G. Skopp; A. Alt

2011-01-01

7

Blood kinetics of ethyl glucuronide and ethyl sulphate in heavy drinkers during alcohol detoxification  

Microsoft Academic Search

Studies of ethyl glucuronide (EtG) blood kinetics have so far been performed on healthy volunteers with ingestion of low to moderate doses of ethanol. These data are not necessarily transferable to heavy drinkers where the consumed doses of ethanol are much higher. The aim of this study was to investigate the pharmacokinetics of EtG and ethyl sulphate (EtS) in blood

Gudrun Høiseth; Luca Morini; Aldo Polettini; Asbjørg Christophersen; Jørg Mørland

2009-01-01

8

Ethyl glucuronide: on the time course of excretion in urine during detoxification  

Microsoft Academic Search

Ethyl glucuronide (EtG) is a promising new biological state marker of recent alcohol consumption that detects alcohol use reliably over a definite time period. Other currently available markers lack acceptable sensitivity and specificity. Our aim is to elucidate under naturalistic conditions the time course of EtG excretion in urine following alcohol consumption and to show how this can be utilized

Friedrich Martin Wurst; Stephan Seidl; Dieter Ladewig; Franz Müller-Spahn; Andreas Alt

2002-01-01

9

A novel and an effective analytical approach for the LCMS determination of ethyl glucuronide and ethyl sulfate in urine  

Microsoft Academic Search

An alternative liquid chromatography-mass spectrometry (LC-MS) method based on no discharge (ND) atmospheric pressure chemical ionization (APCI) was developed for the simultaneous determination of ethyl glucuronide (EtG) and ethyl sulfate (EtS) in urine in negative ion conditions. Abundant [M-H] - species of EtG and EtS were obtained, allowing to reach limits of quantification (0.1 ?g\\/ml for both analytes), accuracy, and

Donata Favretto; Alessandro Nalesso; Giampietro Frison; Guido Viel; Pietro Traldi; Santo Davide Ferrara

2010-01-01

10

In vitro study of bacterial degradation of ethyl glucuronide and ethyl sulphate  

Microsoft Academic Search

Recent studies show that ethyl glucuronide (EtG) can be decomposed by bacteria; whilst so far no degradation of ethyl sulphate\\u000a (EtS) has been observed. In the present study, in vitro experiments with bacterial colonies were performed. Bacteria (Escherichia coli, Klebsiella pneumoniae, Clostridium sordellii) were isolated from autopsy material (liver, heart blood, urine, ascites, pericardial fluid, pleural fluid) tested for ?-glucuronidase

Stefanie Baranowski; Annerose Serr; Annette Thierauf; Wolfgang Weinmann; Markus Gro?e Perdekamp; Friedrich M. Wurst; Claudia C. Halter

2008-01-01

11

Assessment of UDP-glucuronosyltransferase catalyzed formation of ethyl glucuronide in human liver microsomes and recombinant UGTs  

Microsoft Academic Search

While ethanol is primarily metabolized to acetaldehyde and acetic acid via alcohol dehydrogenase, a minor but increasingly important pathway in the field of forensic science involves the conjugation of glucuronic acid to form an ethyl glucuronide (EtG) metabolite. The kinetics of ethyl glucuronide formation were examined in human liver microsomes (HLM) and recombinant UDP-glucuronosyltransferases (UGTs). The metabolite exhibited a relatively

Robert S. Foti; Michael B. Fisher

2005-01-01

12

Distribution of ethyl glucuronide in rib bone marrow, other tissues and body liquids as proof of alcohol consumption before death  

Microsoft Academic Search

Postmortem ethyl glucuronide (EtG) concentrations in rib bone marrow, liver, muscle, fat tissue, urine, blood and bile have been determined by LC–MS\\/MS. Samples have been taken from twelve corpses during autopsies. In nine corpses EtG could be detected, corresponding blood ethanol concentrations (BAC) were 0.04–0.37g%. In three cases, no EtG was found; two of these cases showed postmortem BACs –

Haiko Schloegl; Thomas Rost; Wolfgang Schmidt; Friedrich Martin Wurst; Wolfgang Weinmann

2006-01-01

13

Abstinence Monitoring of Suspected Drinking Drivers: Ethyl Glucuronide in Hair Versus CDT  

Microsoft Academic Search

Objective: Ethyl glucuronide (EtG) determinations in the hair of self-reported teetotalers were reviewed and compared with carbohydrate-deficient transferrin (CDT) blood tests (by immunochemistry and high-performance liquid chromatography [HPLC]).Methods: A retrospective study was carried out on 154 people whose fitness to drive had to be assessed because of the suspicion of relevant alcohol problems.Results: EtG was detected in 55 percent of

Bruno Liniger; Ariane Nguyen; Andrea Friedrich-Koch; Michel Yegles

2010-01-01

14

Ethyl glucuronide determination in meconium and hair by hydrophilic interaction liquid chromatography–tandem mass spectrometry  

Microsoft Academic Search

Ethyl glucuronide (EtG) detection in non-conventional matrices, such as hair and meconium, can provide useful information on alcohol abuse over a long time frame, for example during pregnancy or after a withdrawal treatment. This study reports on the development, validation and application of a new hydrophilic interaction liquid chromatography–tandem mass spectrometry (HILIC–MS\\/MS) method for the analysis of EtG in meconium

Isabela Tarcomnicu; Alexander L. N. van Nuijs; Katrien Aerts; Mireille De Doncker; Adrian Covaci; Hugo Neels

2010-01-01

15

Urine tested positive for ethyl glucuronide and ethyl sulphate after the consumption of “non-alcoholic” beer  

Microsoft Academic Search

In abstinence maintenance programs, for reissuing the driving licence and in workplace monitoring programs abstinence from ethanol and its proof are demanded. Various monitoring programs that mainly use ethyl glucuronide (EtG) as alcohol consumption marker have been established. To abstain from ethanol, but not from the taste of alcoholic beverages, in particular non-alcoholic beer has become more and more popular.

Annette Thierauf; Heike Gnann; Ariane Wohlfarth; Volker Auwärter; Markus Große Perdekamp; Klaus-Juergen Buttler; Friedrich M. Wurst; Wolfgang Weinmann

2010-01-01

16

Stability of ethyl glucuronide in urine, post-mortem tissue and blood samples  

Microsoft Academic Search

The stability of ethyl glucuronide (EtG) under conditions of degradation was examined in urine samples of nine volunteers\\u000a and in post-mortem tissue (liver, skeletal muscle) and blood taken from seven corpses at autopsies. Analysis was performed\\u000a via LC-MS\\/MS. EtG concentrations in urine samples ranged from 2.5 to 296.5 mg\\/l. When stored at 4°C in airtight test tubes,\\u000a EtG concentrations remained relatively

Haiko Schloegl; Sebastian Dresen; Karin Spaczynski; Mylène Stoertzel; Friedrich Martin Wurst; Wolfgang Weinmann

2006-01-01

17

Voucher-Based Reinforcement for Alcohol Abstinence Using the Ethyl-Glucuronide Alcohol Biomarker  

ERIC Educational Resources Information Center

|This study assessed the effects of a contingency management (CM) intervention for alcohol consumption in 10 alcohol-dependent participants. An ABCA design was used. Vouchers were provided contingent on results of ethyl glucuronide (EtG) urine tests (an alcohol biomarker with a 2-day detection period) and alcohol breath tests during the C phase.…

McDonell, Michael G.; Howell, Donelle N,; McPherson, Sterling; Cameron, Jennifer M.; Srebnik, Debra; Roll, John M.; Ries, Richard K.

2012-01-01

18

Ethyl glucuronide excretion in humans following oral administration of and dermal exposure to ethanol.  

PubMed

Ethyl glucuronide (EtG) is a direct ethanol biomarker and U.S. Department of Health and Human Services has advised that specificity studies at low EtG levels are needed for distinction of ethanol consumption and incidental exposure. The authors report urinary EtG excretion with ethanol abstinence, dermal exposure and oral consumption. EtG concentration by sensitive liquid chromatography-tandem mass spectrometry measurement in 39 urine specimens from adult alcohol abstainers (< 10-62 microg/L) and in urine from 13 children (< 10-80 microg/L) indicates either unrecognized ethanol exposure or endogenous ethanol metabolism. With repetitive daily dermal exposure to hand sanitizer (60% ethanol) by 9 adults, EtG concentration ranged from < 10 to 114 microg/L in 88 first-morning void specimens. EtG excretion following a 24 g ethanol drink by 4 adults revealed maximum urine EtG concentration (12,200-83,200 microg/L) at 3 to 8 h postdose and an EtG detection window up to 25-39 h, compared to an ethanol window of only 2 to 4 h. Oral ethanol use also showed an increase in the percent (molar equivalent) ethanol excreted as EtG with increasing oral ethanol doses. Human excretion studies show 1. EtG detectable at low concentration (< 100 microg/L) when ethanol use or exposures is not evident, 2. EtG concentration less than 120 microg/L in first morning specimens from adults with repeated dermal exposure to ethanol, 3. EtG levels maximally elevated within 3-8 h and above baseline for up to 39 h after a 24 g ethanol drink, and 4. a dose-dependent increase in the percentage of ethanol excreted as EtG with increasing oral ethanol use. PMID:19007508

Rosano, Thomas G; Lin, Jing

2008-10-01

19

The influence of ethanol containing cosmetics on ethyl glucuronide concentration in hair  

Microsoft Academic Search

Ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEE), non-volatile, direct metabolites of ethanol have been shown to be suitable markers for the evaluation of social and chronic excessive alcohol consumption. Previous investigations have shown that the regular use of hair-care products with high alcohol content lead to an increase of FAEE concentration and consequently gave false-positive results for the

Liliane Martins Ferreira; Tina Binz; Michel Yegles

20

Validation of a headspace solid-phase microextraction–GC–MS\\/MS for the determination of ethyl glucuronide in hair according to forensic guidelines  

Microsoft Academic Search

The analysis of ethyl glucuronide (EtG) in hair is a powerful tool for chronic alcohol abuse control because of the typical wide detection window of the hair matrix and due to the possibility of segmentation, allowing evaluation of alcohol consumption in different periods. Additionally, EtG in hair is often the only diagnostic parameter of choice for alcohol abuse when other

Ronald Agius; Thomas Nadulski; Hans-Gerhard Kahl; Johannes Schräder; Bertin Dufaux; Michel Yegles; Fritz Pragst

2010-01-01

21

Blood kinetics of ethyl glucuronide and ethyl sulphate in heavy drinkers during alcohol detoxification.  

PubMed

Studies of ethyl glucuronide (EtG) blood kinetics have so far been performed on healthy volunteers with ingestion of low to moderate doses of ethanol. These data are not necessarily transferable to heavy drinkers where the consumed doses of ethanol are much higher. The aim of this study was to investigate the pharmacokinetics of EtG and ethyl sulphate (EtS) in blood in heavy drinkers after termination of alcohol ingestion. Sixteen patients from an alcohol withdrawal clinic were included directly after admission. Time of end of drinking, estimated daily intake of ethanol (EDI) and medical history were recorded. Three to five blood samples over 20-43 h were collected from each patient subsequent to admission. The median EDI was 172 g (range 60-564). The first sample was collected median 2.5 h after end of drinking (range 0.5-23.5). Two patients had levels of EtG and EtS below LOQ in all samples, the first collected 19.25 and 23.5 h after cessation of drinking, respectively. Of the remaining 14 patients, one subject, suffering from both renal and hepatic disease, showed concentrations of EtG and EtS substantially higher than the rest of the material. This patient's initial value of EtG was 17.9 mg/L and of EtS 5.9 mg/L, with terminal elimination half lives of 11.9 h for EtG and 12.5 h for EtS. Among the remaining 13 patients, the initial median values were 0.7 g/L (range 0-3.7) for ethanol, 1.7 mg/L (range 0.1-5.9) for EtG and 0.9 mg/L (range 0.1-1.9) for EtS. Elimination occurred with a median half-life of 3.3 h for EtG (range 2.6-4.3) and 3.6 h for EtS (range 2.7-5.4). In conclusion, elimination of EtG in heavy drinkers did not significantly differ from healthy volunteers, and EtS appeared to have similar elimination rate. In the present work, there was one exception to this, and we propose that this could be explained by the patient's renal disease, which would delay excretion of these conjugated metabolites. PMID:19395207

Høiseth, Gudrun; Morini, Luca; Polettini, Aldo; Christophersen, Asbjørg; Mørland, Jørg

2009-04-23

22

Comparison of ethyl glucuronide in hair with phosphatidylethanol in whole blood as post-mortem markers of alcohol abuse  

Microsoft Academic Search

Ethyl glucuronide (EtG) is a direct metabolite of ethanol and has been used as a marker of alcohol abuse in both urine and hair. This study investigated the value of EtG testing in post-mortem hair for diagnostic improvement of alcohol abuse in forensic medicine. Material from 70 consecutive medico-legal autopsies was collected in accordance with the recommendations on ethics by

Peter Bendroth; Robert Kronstrand; Anders Helander; Jesper Greby; Nikolai Stephanson; Peter Krantz

2008-01-01

23

Ethyl glucuronide, ethyl sulfate, and ethanol in urine after sustained exposure to an ethanol-based hand sanitizer.  

PubMed

To assess the degree of ethanol absorption and subsequent formation of urinary ethyl glucuronide (EtG) and ethyl sulfate (EtS) following sustained application of hand sanitizer, 11 volunteers cleansed their hands with Purell(™) hand sanitizer (62% ethanol) every 5 min for 10 h on three consecutive days. Urine specimens were obtained at the beginning and end of each day of the study, and on the morning of the fourth day. Urinary creatinine, ethanol, EtG, and EtS concentrations were measured. EtG was undetectable in all pre-study urine specimens, but two pre-study specimens had detectable EtS (73 and 37 ng/mL). None of the pre-study specimens had detectable ethanol. The maximum EtG and EtS concentrations over the course of the study were 2001 and 84 ng/mL, respectively, and nearly all EtG- and EtS-positive urine specimens were collected at the conclusion of the individual study days. Only two specimens had detectable EtG at the beginning of any study day (96 and 139 ng/mL), and only one specimen had detectable EtS at the beginning of a study day (64 ng/mL), in addition to the two with detectable EtS prior to the study. Creatinine-adjusted maximum EtG and EtS concentrations were 1998 and 94 ?g/g creatinine, respectively. In patients being monitored for ethanol use by urinary EtG concentrations, currently accepted EtG cutoffs do not distinguish between ethanol consumption and incidental exposures, particularly when urine specimens are obtained shortly after sustained use of ethanolcontaining hand sanitizer. Our data suggest that EtS may be an important complementary biomarker in distinguishing ethanol consumption from dermal exposure. PMID:21396227

Reisfield, Gary M; Goldberger, Bruce A; Crews, Bridgit O; Pesce, Amadeo J; Wilson, George R; Teitelbaum, Scott A; Bertholf, Roger L

2011-03-01

24

Development and validation of a gas chromatography–negative chemical ionization tandem mass spectrometry method for the determination of ethyl glucuronide in hair and its application to forensic toxicology  

Microsoft Academic Search

Ethyl glucuronide (EtG) is a minor and direct metabolite of ethanol. EtG is incorporated into the growing hair allowing retrospective investigation of chronic alcohol abuse. In this study, we report the development and the validation of a method using gas chromatography–negative chemical ionization tandem mass spectrometry (GC–NCI-MS\\/MS) for the quantification of EtG in hair. EtG was extracted from about 30mg

Hicham Kharbouche; Frank Sporkert; Stéphanie Troxler; Marc Augsburger; Patrice Mangin; Christian Staub

2009-01-01

25

Voucher-based reinforcement for alcohol abstinence using the ethyl-glucuronide alcohol biomarker.  

PubMed

This study assessed the effects of a contingency management (CM) intervention for alcohol consumption in 10 alcohol-dependent participants. An ABCA design was used. Vouchers were provided contingent on results of ethyl glucuronide (EtG) urine tests (an alcohol biomarker with a 2-day detection period) and alcohol breath tests during the C phase. The percentage of negative urines was 35% during the first baseline phase, 69% during the C phase, and 20% during the return-to-baseline phase. Results suggest that EtG urine tests may be a feasible method to deliver CM to promote alcohol abstinence. PMID:22403460

McDonell, Michael G; Howell, Donelle N; McPherson, Sterling; Cameron, Jennifer M; Srebnik, Debra; Roll, John M; Ries, Richard K

2012-01-01

26

VOUCHER-BASED REINFORCEMENT FOR ALCOHOL ABSTINENCE USING THE ETHYL-GLUCURONIDE ALCOHOL BIOMARKER  

PubMed Central

This study assessed the effects of a contingency management (CM) intervention for alcohol consumption in 10 alcohol-dependent participants. An ABCA design was used. Vouchers were provided contingent on results of ethyl glucuronide (EtG) urine tests (an alcohol biomarker with a 2-day detection period) and alcohol breath tests during the C phase. The percentage of negative urines was 35% during the first baseline phase, 69% during the C phase, and 20% during the return-to-baseline phase. Results suggest that EtG urine tests may be a feasible method to deliver CM to promote alcohol abstinence.

McDonell, Michael G; Howell, Donelle N; McPherson, Sterling; Cameron, Jennifer M; Srebnik, Debra; Roll, John M; Ries, Richard K

2012-01-01

27

Ethyl glucuronide and ethyl sulfate in autopsy samples 27 years after death.  

PubMed

The unique case of a 50-year-old known alcoholic whose corpse was exhumed 27 years after death is reported. The man apparently committed suicide by hanging, but many years later the case was questioned and homicide-linked to a long-lasting serial killer case-was suspected. Thus, the corpse was exhumed, and at the autopsy it was found to be naturally mummified. This fact permitted the analysis of body tissues with the aim to investigate the persistence of ethanol conjugates in the biological material 27 years after death. Fragments of liver and kidney, a blood clot, and a hair strand were collected and submitted to liquid chromatography tandem mass spectrometry analysis. Ethyl glucuronide (EtG) and ethyl sulfate (EtS) were identified and quantified in the liver, the kidney, and the blood clot. Hair analysis was found to be severely affected by ion suppression even after solid phase extraction. Consequently, EtG was identified in all hair segments (0-3 cm, 3-6 cm, and 6-10 cm), but no reliable quantification could be carried out. In summary, our findings demonstrate that, notwithstanding the expected conjugate degradation, EtG and EtS can be indicative of ante-mortem use of alcohol even many years after death. PMID:18661140

Politi, Lucia; Morini, Luca; Mari, Francesco; Groppi, Angelo; Bertol, Elisabetta

2008-07-26

28

ETHYL GLUCURONIDE — A MARKER OF ALCOHOL CONSUMPTION AND A RELAPSE MARKER WITH CLINICAL AND FORENSIC IMPLICATIONS  

Microsoft Academic Search

Ethyl glucuronide (EtG) is a non-volatile, water-soluble, direct metabolite of ethanol that can be detected in body fluids and hair. We investigated urine and serum samples from three patient groups: (1) 33 in-patients in acute alcohol withdrawal; (2) 30 detoxified in-patients (treated for at least 4 weeks) from a 'motivation station'; and (3) 43 neuro-rehabilitation patients (non-alcoholics; most of them

FRIEDRICH MARTIN WURST; CHRISTOPH KEMPTER; STEPHAN SEIDL; ANDREAS ALT

29

Determination of ethyl glucuronide in human hair by SPE and LC–MS\\/MS  

Microsoft Academic Search

A method for the sensitive and selective determination of ethyl glucuronide (EtG) in hair has been developed using solid-phase extraction (SPE) and liquid chromatography–tandem mass spectrometry (LC–MS\\/MS). Washed and cut hair segments were extracted by ultrasonication (3h, 50°C) and the extracts were cleaned-up with aminopropyl SPE columns. LC–MS\\/MS analysis was performed using a polar-endcapped phenyl-hexyl-RP-phase with negative mode electrospray ionisation

Ines Janda; Wolfgang Weinmann; Thorsten Kuehnle; Martina Lahode; Andreas Alt

2002-01-01

30

Determination of ethyl glucuronide in hair samples by liquid chromatography/electrospray tandem mass spectrometry.  

PubMed

A method for the determination of ethyl glucuronide (EtG) in hair samples, using liquid chromatography/electrospray tandem mass spectrometry (LC/ESI-MS/MS), was developed and validated. The treatment of hair samples was as follows: to 100 mg of washed (dichloromethane followed by methanol, 1 ml each) and cut (1-2 mm) material, 700 microl of water, 20 microl of internal standard solution (pentadeuterated EtG, D(5)-EtG, 500 microg/l) and 20 microl of methanol were added. Samples were incubated at 25 degrees C overnight and then ultrasonicated for 2 h. Finally, 8 microl of the centrifuged solution (13,000 rpm) were analyzed by LC/ESI-MS/MS in negative ion mode. The surviving ions of EtG and D(5)-EtG were monitored together with the following MRM transitions: m/z 221 --> 75, m/z 221 --> 85 (EtG) and m/z 226 --> 75, m/z 226 --> 85 (D(5)-EtG). The method exhibited a mean correlation coefficient better than 0.9998 over the dynamic range (3-2000 pg/mg). The lower limit of quantification (LLOQ) and the limit of detection (LOD) were 3 and 2 pg/mg respectively. The intra- and interday precision and accuracy were studied at four different concentration levels (3, 5, 56 and 160 pg/mg) and were always better than 7% (n = 5). Matrix effects did not exceed 20%. The method was applied to several hair samples taken from autopsies of known alcoholics, from patients in withdrawal treatment, from social drinkers, from adult teetotalers and from children not exposed to ethanol, with EtG concentrations globally ranging from < or =2 to 4180 pg/mg. PMID:16287042

Morini, Luca; Politi, Lucia; Groppi, Angelo; Stramesi, Cristiana; Polettini, Aldo

2006-01-01

31

Microwave-assisted extraction: a simpler and faster method for the determination of ethyl glucuronide in hair by gas chromatography–mass spectrometry  

Microsoft Academic Search

Alcohol is the most frequently abused “addictive substance” that causes serious social problems throughout the world; thus,\\u000a alcoholism is of particular interest in clinical and forensic medicine. Alcohol biomarkers are physiological indicators of\\u000a alcohol exposure or ingestion and may reflect the presence of an alcohol use disorder. The glucuronide conjugation is a minor\\u000a pathway of ethanol metabolism. Ethyl glucuronide (EtG)

Iván Álvarez; Ana María Bermejo; María Jesús Tabernero; Purificación Fernández; Pamela Cabarcos; Patricia López

2009-01-01

32

A High-Performance Liquid Chromatographic-Tandem Mass Spectrometric Method for the Determination of Ethyl Glucuronide and Ethyl Sulfate in Urine Validated According to Forensic Guidelines  

PubMed Central

Ethyl glucuronide (EtG) and ethyl sulfate (EtS) are powerful markers for alcohol intake and abuse. Several analytical procedures for the quantification of EtG and EtG in serum and urine have been developed so far. Many of the published methods show limits of detections (LODs) or limits of quantifications (LOQs) for EtG in urine within the range of 0.1 mg/L or higher. Since this is the actual cutoff value for proving abstinence in Germany, problems may occur if urine samples are highly diluted. In this paper, the validation of a highly sensitive, fast and simple LC–MS–MS for the determination of EtG and EtS in urine is described. The calibration curves for EtG and EtS is linear over the whole range (0.025–2.0 mg/L). Very low detection limits can be achieved (LOD: EtG 0.005 mg/L, EtS 0.005 mg/L; and LOQ: EtG 0.019 mg/L, EtS 0.015 mg/L). All data for selectivity, precision and accuracy, recovery, as well as for the processed sample and the freeze/thaw stability, comply with the guidelines of the German Society of Toxicological and Forensic Chemistry. Strong matrix-related effects can be compensated for by using an internal standard. Finally, the applicability of the procedure is proven by analysis of 87 human urine samples and by successful participation in interlaboratory comparison tests.

Albermann, M.E.; Musshoff, F.; Madea, B.

2012-01-01

33

Determination of ethyl glucuronide in human hair by SPE and LC-MS/MS.  

PubMed

A method for the sensitive and selective determination of ethyl glucuronide (EtG) in hair has been developed using solid-phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Washed and cut hair segments were extracted by ultrasonication (3h, 50 degrees C) and the extracts were cleaned-up with aminopropyl SPE columns. LC-MS/MS analysis was performed using a polar-endcapped phenyl-hexyl-RP-phase with negative mode electrospray ionisation (ESI) using a triple quadrupole mass spectrometer (Sciex API 365) with a turboionspray source and post-column addition of acetonitrile for enhanced sensitivity. The MS/MS transitions monitored were m/z 221 -->75 for EtG and 226 -->75 for D(5)-EtG as an internal standard. The method was selective and sensitive, with a detection limit of 51 pg/mg hair at a signal-to-noise ratio of 3:1. The mean recovery was 96%, with an intra- and inter-day precision of less than 11.7% at a concentration of 200 pg/mg. The linearity was assessed in the range of 25-2000 pg/mg hair, with a correlation coefficient of 0.997. The method was successfully applied to 97 human hair samples which were taken at autopsies from persons with known alcoholism or were obtained from alcoholics who were hospitalized for ethanol withdrawal, from social drinkers and from children having not consumed any alcohol. Although, approximately two-third of the alcoholics showed EtG concentrations in hair of higher than 51 pg/mg (up to >4000 pg/mg), in one-third the EtG concentration was below the detection limit. However, only in one of five hair samples of "social drinkers", the EtG concentration was above the detection limit (51 pg/mg). No EtG has been detected in the hair of children. These investigations demonstrate that heavy alcohol consumption may be but not necessarily has to be detectable by EtG analysis in hair. PMID:12208024

Janda, Ines; Weinmann, Wolfgang; Kuehnle, Thorsten; Lahode, Martina; Alt, Andreas

2002-08-14

34

A fully validated high-performance liquid chromatography-tandem mass spectrometry method for the determination of ethyl glucuronide in hair for the proof of strict alcohol abstinence  

Microsoft Academic Search

Hair analysis has become a powerful tool for the detection of chronic and past drug consumption. For several years, it has\\u000a been possible to determine even the intake of ethanol in hair samples by detecting the ethanol metabolites ethyl glucuronide\\u000a or fatty acid ethyl esters. Recently, new requirements were published for the use of EtG as an abstinence test (c

Maria Elena Albermann; F. Musshoff; B. Madea

2010-01-01

35

Urinary concentrations of ethyl glucuronide and ethyl sulfate as thresholds to determine potential ethanol-induced alteration of steroid profiles.  

PubMed

The suppression of steroid biotransformation resulting in a decrease of the major urinary metabolites--androsterone and etiocholanolone--and the elevation of testosterone/epitestosterone (T/E) ratios following ethanol administration is well described. At least the latter parameter T/E represents an important indicator for endogenous steroid abuse in doping control. The quantitative correlation between ethanol consumption markers and steroid profile alteration was evaluated, aiming to differentiate between permitted ethanol administration and potential steroid abuse. Steroid profiles, ethanol, ethyl glucuronide (EtG), and sulfate (EtS) were quantified after administration of ethanol (intended maximum ethanol concentration in blood was 1 mg/g) to 21 male and 15 female volunteers. EtG concentrations in urine (corrected by either specific gravity or creatinine concentration) were found to be most suitable for quantitative evaluations. Gender specific urinary EtG concentrations of 48 ug/ml (men) and 15.5 ug/ml (women) may be considered as useful thresholds for a potential ethanol-induced suppression of steroids biotransformation. PMID:22213685

Thieme, D; Grosse, J; Keller, L; Graw, M

36

Preliminary investigations on ethyl glucuronide and ethyl sulfate cutoffs for detecting alcohol consumption on the basis of an ingestion experiment and on data from withdrawal treatment.  

PubMed

Ethyl glucuronide (EtG) and ethyl sulfate (EtS) are commonly used alcohol markers for previous alcohol consumption. Nevertheless, the optimum EtG cutoff for urinary abstinence tests is still being discussed, and no cutoff has been recommended for EtS yet. The aim of this study was to verify cutoffs by investigating EtG and EtS concentrations (c(EtG) and c(EtS)) in the urine of healthy persons after drinking small, but realistic amounts of alcohol (one or two glasses of beer or white wine), and to look for the window of detection in strongly alcohol-intoxicated patients who were beginning withdrawal treatment. Very high EtG and EtS concentrations were measured in the first urine samples of patients under withdrawal treatment. However, 24 h later, concentrations decreased considerably, and c (EtG)?EtG) and 0.05 mg/l (EtS) were measured for 23.5 and 20.5 h after consuming 0.1 l of white wine or 0.33 l of beer, and 24 h after the experiment, 75 % (9/12) of the urine samples were tested negative for EtG and EtS using the following cutoffs: EtG 0.5 mg/l and EtS 0.1 mg/l. In half of the samples, concentrations below 0.1 mg/l (EtG) and 0.05 mg/l (EtS) were detected. Urinary cutoffs for EtG of 0.5 mg/l or higher are not suitable for testing abstinence. Even 0.1 mg/l is not effective to detect the intake of small amounts of alcohol in the context of abstinence tests. For EtS, 0.05 mg/l were found to be a potential cutoff to exclude the repeated intake of alcohol. Yet, further research is required to verify this cutoff. For a limited time period, EtG and EtS concentrations within the range of these cutoffs are also detectable after unintentional consumption of alcohol. Participants of abstinence programs have to be informed about the alcohol content of certain foods and beverages whose consumption is in conflict with strict abstinence. PMID:22752748

Albermann, Maria Elena; Musshoff, Frank; Doberentz, Elke; Heese, Peter; Banger, Markus; Madea, Burkhard

2012-06-30

37

Immunoassay for ethyl glucuronide in vitreous humor: a new tool for postmortem diagnostics of alcohol use.  

PubMed

Although excessive alcohol consumption plays a major role in fatal events, the role of alcohol use as a possible contributing factor at the time of death is not easy to establish due to lack of suitable biomarkers for postmortem analyses. We used an immunological approach to measure ethyl glucuronide (EtG) concentrations from vitreous humor (VH) and serum from 58 individuals representing a forensic autopsy population of cases with either a well-documented history of excessive alcohol use (n=37) or cases without such history (n=21), according to medical and police records and blood alcohol determinations (BAC). The immunoassay was based on the Microgenics DRI-EtG EIA reagents applied on an automated Abbott Architect c8000 clinical chemistry analyzer. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) determination of EtG and ethyl sulfate (EtS) was used as a reference method. At a cut-off of 0.3mg/l for VH-EtG, the immunoassay correctly identified 92% of the cases with a history of excessive alcohol use, whereas the BAC was positive (cut-off 10mg/dl) in 68% of the cases. A significant correlation emerged between VH-EtG and serum EtG (r=0.77, p<0.001) and between VH-EtG and BAC (r=0.62, p<0.001), although VH-EtG was frequently elevated also in cases with no detectable BAC. The EtG immunoassay showed a strong correlation with the LC-MS/MS reference method (r=0.94, p<0.001) and there was 100% agreement in the frequency of marker positive and negative findings between the immunoassay EtG results and the LC-MS/MS analysis of EtG and EtS. The present data indicate that the immunoassay for VH-EtG is a useful forensic tool for screening of antemortem alcohol use. PMID:23415594

Rainio, Juha; Kultti, Johanna; Kangastupa, Päivikki; Tuomi, Heidi; Ahola, Sanna; Karhunen, Pekka J; Helander, Anders; Niemelä, Onni

2013-02-13

38

Determination of ethyl-glucuronide in hair for heavy drinking detection using liquid chromatography-tandem mass spectrometry following solid-phase extraction  

Microsoft Academic Search

The detection of ethyl-?-d-6-glucuronide (EtG), a stable phase II metabolite of ethanol, is of interest in both clinical and forensic contexts with\\u000a the aim of monitoring alcohol abuse. We present a liquid chromatography-electrospray ionisation-tandem mass spectrometry method\\u000a for the detection and quantification of EtG in hair. Thirty milligrams of washed and cut hair were cleaned up using solid-phase\\u000a extraction graphite

Fabien Lamoureux; Jean-michel Gaulier; François-Ludovic Sauvage; Magali Mercerolle; Christine Vallejo; Gérard Lachâtre

2009-01-01

39

Practical experiences in application of hair fatty acid ethyl esters and ethyl glucuronide for detection of chronic alcohol abuse in forensic cases.  

PubMed

This article presents results from 1872 hair samples, which were analyzed for fatty acid ethyl esters (FAEEs) and ethyl glucuronide (EtG). The results were evaluated in the context of self-reported drinking behavior, the use of hair cosmetics, the gender of the sample donors and hair sample length. For comparison, CDT and GGT in serum were available in 477 and 454 cases, respectively. A number of alcohol abstainers or low moderate drinkers and excessive drinkers were selected for assessment of cut-offs for FAEEs in the proximal 6cm hair segments and for EtG in the proximal 3cm hair segments. Cut-off values were assessed by ROC analysis. It was found that the cut-offs of 1.0ng/mg FAEE and 30pg/mg EtG presently used for excessive drinking lead to a low portion of false positives (4% and 3% respectively) but to a higher portion of false negatives (23% and 25% respectively). Comparison of the mean and medium concentrations in samples without any reported hair cosmetics (N=1079) and in samples with reported use of hair spray (N=79) showed an increase by the factor of about two for FAEE but no significant difference for EtG. Mean values of EtG were decreased by 80% in bleached samples (N=164) and by 63% in dyed samples (N=96). There was no significant effect of bleaching and dyeing on FAEE. Hair gel and hair wax, oil or grease showed no significant effect on both FAEE and EtG. With respect to gender and investigated hair length ambiguous results were obtained because of major differences in the compared subpopulations of male with higher alcohol consumption and mainly shorter hair, and less drinking female with longer hair. For excessive drinkers FAEEs in the 0-6cm hair segment and EtG in the 0-3cm segment decreased with increasing time of reported abstinence before sample collection. These drinkers attain the level of teetotalers only after more than 10 months of abstinence. In comparison to scalp hair, FAEEs recovered from armpit hair and leg hair were lower and from chest hair were higher. EtG in armpit hair was lower and in leg hair higher than in scalp hair. It is concluded that the combined use of FAEE and EtG essentially increases the accuracy of interpretation since both markers complement each other by a different sensitivity to sources of error. PMID:22036309

Suesse, S; Pragst, F; Mieczkowski, T; Selavka, C M; Elian, A; Sachs, H; Hastedt, M; Rothe, M; Campbell, J

2011-10-27

40

COMPARISON BETWEEN THE URINARY ALCOHOL MARKERS EtG, EtS, AND GTOL\\/5HIAA IN A CONTROLLED DRINKING EXPERIMENT  

Microsoft Academic Search

Aim: Urinary ethyl glucuronide (EtG), ethyl sulfate (EtS), and the ratio between 5-hydroxytryptophol-glucuronide and 5-hydroxyindole-3-acetic acid (GTOL\\/5-HIAA) are all suggested as biomarkers for recent alcohol ingestion with longer detection times than measurement of ethanol itself. The aim of this controlled study was to compare the sensitivities and detection times of EtG, EtS, and GTOL\\/5-HIAA, after a single ingestion of ethanol.

GUDRUN HØISETH; JEAN PAUL BERNARD; NICOLAI STEPHANSON; PER T. NORMANN; ASBJØRG S. CHRISTOPHERSEN; ANDERS HELANDER

41

An improved method to detect ethyl glucuronide in urine using reversed-phase liquid chromatography and pulsed electrochemical detection.  

PubMed

Pulsed electrochemical detection (PED) following reversed-phase liquid chromatography (LC) has been applied recently to the detection of ethyl glucuronide (EtG) in the urine of live and deceased individuals. In this paper, several key improvements to the method are made to enhance sensitivity, reproducibility, and accuracy. These improvements include (i) further optimization of the sample preparation procedure that has increased the recovery from ca. 50% to 84+/-3% in synthetic urine matrix; (ii) changing the internal standard from methyl glucuronide (MetG) to propyl glucuronide (ProG), which does not elute within the interference of the matrix; and (iii) altering the mobile phase of the separation from acetonitrile to t-butanol to virtually eliminate signal suppression in PED. As a consequence, detection limits have been reduced to 0.01 microg mL(-1), reproducibility has been improved by a factor of two, and sample size has been reduced five-fold. Blind studies in synthetic urine showed no significant difference between the amount recovered and the true value determined at the 95% confidence level for all samples. Importantly, PED requires no derivatization, and it can detect virtually all glucuronides. PMID:17723638

Shah, Romina; Lacourse, William R

2006-06-16

42

Diagnosis of chronic alcohol consumption. Hair analysis for ethyl-glucuronide.  

PubMed

This paper describes a procedure for the detection and quantification of ethyl-glucuronide (EtG) in hair samples. During method development the efficacy of extraction of EtG from hair was compared in four extraction methods: (a) methanol; (b) methanol:water (1:1); (c) water; and (d) water:trifluoroacetic acid (9:1). In addition, three derivatizing agents were compared as well: N,O-bistrimethylsilyl-trifluoroacetamide (BSTFA): trimethylchlorosilane (TMCS) (99:1), pentafluoropropionic anhydride (PFPA) and heptafluorobutyric anhydride (HFBA). Water was found to be the best extracting solvent and PFPA the best derivatizing agent. Both provided the highest recoveries, with cleaner extracts and more stable derivatives. The final method is as follows: about 100mg of hair are sequentially washed with water and acetone. The decontaminated sample is finely cut with scissors, then the deuterated internal standard (EtG-d5) and 2 mL of water are added. After sonication for 2 h, the sample is maintained at room temperature overnight. Derivatization is performed with PFPA. Derivatives are injected into a GC-MS system in the electronic impact mode. The method shows linearity over the range of concentrations from 0.050 to 5 ng/mg. Detection and quantification limits are 0.025 and 0.050 ng/mg, respectively. Mean recoveries for the three studied concentrations (low, medium and high) are higher than 87%. The coefficients of variation in intra- and inter-assay precision are always lower than 7%. The method is being routinely applied in our lab for the diagnosis of chronic alcohol consumption. PMID:15451088

Jurado, C; Soriano, T; Giménez, M P; Menéndez, M

2004-10-29

43

Ethyl glucuronide concentrations in oral fluid, blood, and urine after volunteers drank 0.5 and 1.0 g/kg doses of ethanol.  

PubMed

The aim of this study was to investigate the concentrations of ethyl glucuronide (EtG) in oral fluid, blood, and urine after healthy volunteers drank two doses of ethanol, 0.5 (n = 11) and 1.0 g/kg (n = 10), after an overnight fast. Samples of oral fluid, blood, and urine were collected before drinking started and at 1.5, 3.5, 5.5, 8.5, 11.5, and 24 h post-dosing. Following ingestion of low dose of ethanol, the Cmax for EtG was 0.36 mg/L (range 0.28-0.41 mg/L) in blood and 69.8 mg/L (range 47.1-96.5 mg/L) in urine. In oral fluid, the concentrations were < 1% of those in blood, and only three subjects exceeded the limit of quantification for EtG in oral fluid. After ingestion of the high dose of ethanol, the Cmax for EtG was 1.06 mg/L (range 0.8-1.22 mg/L) in blood, 159.9 mg/L (range 97.2-225.5 mg/L) in urine, and 0.032 mg/L (range 0.013-0.059 mg/L) in oral fluid. The median oral fluid/blood ratio was 0.029 (range 0.012-0.054) for EtG. The detection time for EtG was median 11.5 h (range 3.5-11.5 h) in oral fluid. According to this, the detection time for EtG in oral fluid is therefore only a few hours longer than for ethanol itself and represents limited additional value. PMID:20663284

Høiseth, Gudrun; Yttredal, Borghild; Karinen, Ritva; Gjerde, Hallvard; Mørland, Jørg; Christophersen, Asbjørg

44

Positive EtG findings in hair as a result of a cosmetic treatment  

Microsoft Academic Search

In a case of a driving ability assessment, hair analysis for ethyl glucuronide (EtG) was requested by the authorities. The person concerned denied alcohol consumption and did not present any clinical sign of alcoholism. However, EtG was found in concentrations of up to 910pg\\/mg in hair from different sampling dates suggesting an excessive drinking behavior. The person declared to use

Frank Sporkert; Hicham Kharbouche; Marc P. Augsburger; Clementine Klemm; Markus R. Baumgartner

45

Determination of ethyl glucuronide in nails by liquid chromatography tandem mass spectrometry as a potential new biomarker for chronic alcohol abuse and binge drinking behavior.  

PubMed

A liquid chromatography tandem mass spectrometry method for ethyl glucuronide (EtG) detection and quantification in nails was developed and fully validated. Nails were extracted in 700 ?L double-distilled water. EtG-d(5) was used as an internal standard. Reversed-phase separation was obtained with an isocratic mobile phase composed of 0.1% formic acid and acetonitrile (99:1) for 10 min. Quantification was performed by multiple reaction monitoring of two transitions per compound (EtG and internal standard). The assay was linear from 10 to 500 pg/mg. Validation parameters were studied at three different quality control levels (10, 50, and 300 pg/mg). Intraday, interday, and total imprecision had a coefficient of variation of less than 9.5%. Ion suppression and ion enhancement were negligible (less than 20%). No carryover was detected. The method was applied to several real cases, among teetotalers, social drinkers, and heavy drinkers. A questionnaire, together with the informed consent form, was given to all the participants in order to evaluate alcohol intake in the one month before sample collection. Nail EtG levels in a social drinker were much higher than the concentrations of EtG in hair provided by the same subject, thus suggesting potential high sensitivity in evaluating both chronic excessive alcohol consumption and binge drinking habits. PMID:22193819

Morini, Luca; Colucci, Mario; Ruberto, Maria Giovanna; Groppi, Angelo

2011-12-23

46

Determination of ethyl-glucuronide in hair for heavy drinking detection using liquid chromatography-tandem mass spectrometry following solid-phase extraction.  

PubMed

The detection of ethyl-beta-D-6-glucuronide (EtG), a stable phase II metabolite of ethanol, is of interest in both clinical and forensic contexts with the aim of monitoring alcohol abuse. We present a liquid chromatography-electrospray ionisation-tandem mass spectrometry method for the detection and quantification of EtG in hair. Thirty milligrams of washed and cut hair were cleaned up using solid-phase extraction graphite cartridges. Separation was then performed using an Uptisphere-3SI column, and the detection was operated in the negative mode. After validation, the method was applied to hair samples taken from four fatalities (F) with documented excessive drinking habits, 12 heavy drinkers (HD) and seven social drinkers (SD). The method exhibits limits of detection and quantification of 4 and 10 pg/mg, respectively. Intra- and inter-assay standard deviation and relative bias were less than 20% over the calibrating range (10 to 3,000 pg/mg). EtG hair concentrations in SD were <10 pg/mg and >50 pg/mg for F and HD (range, 54 to 497 pg/mg). The present assay appears convenient to carry out owing to the very small quantity of hair samples required to determine an effective heavy alcohol consumption (EtG hair concentration >50 pg/mg). PMID:19517099

Lamoureux, Fabien; Gaulier, Jean-michel; Sauvage, François-Ludovic; Mercerolle, Magali; Vallejo, Christine; Lachâtre, Gérard

2009-06-12

47

Investigations on the influence of different grinding procedures on measured ethyl glucuronide concentrations in hair determined with an optimized and validated LC-MS/MS method.  

PubMed

Ethyl glucuronide (EtG) analysis in hair is a suitable method for the retrospective determination of previous alcohol consumption. According to the German guidelines, EtG abstinence is improbable at c(EtG)?>?7 pg/mg in the proximal 3 cm of scalp hair. The chromatography of the routinely used liquid chromatography-tandem mass spectrometry procedure was optimized by replacing the stationary phase. To simplify sample preparation, two different mills were tested, and an optimized grinding process was developed. The new method was successfully validated according to the guidelines of the German Society of Toxicological and Forensic Chemistry. Despite a simple extraction procedure without any cleaning steps, a very high sensitivity (limit of detection, 1.7 pg/mg; limit of quantitation, 2.3 pg/mg) could be achieved. Competitive analysis showed significantly higher EtG concentrations in pulverized versus cut hair samples. The strong impact of sample preparation on the determined EtG concentrations suggests the introduction of a standardized sample preparation method to produce comparable results. PMID:22451175

Albermann, M E; Musshoff, F; Aengenheister, L; Madea, B

2012-03-27

48

Analysis of ethyl glucuronide in hair samples by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS).  

PubMed

Many different biomarkers can be used to evaluate ethanol intake. Ethyl glucuronide (EtG) is a direct phase II and minor metabolite of ethanol formed through the UDP-glucuronosyl transferase-catalyzed conjugation of ethanol with glucuronic acid. Its investigation is of interest in both clinical and forensic contexts because of the wide window of detection. A sensitive LC-MS/MS procedure has been developed and fully validated according to the guidelines of forensic toxicology for the analysis of EtG in hair. Sample preparation and chromatographic separation were thoroughly optimized. The analysis was performed in the multiple reaction monitoring mode using the transitions m/z 221 ? 203 (for the quantification) and 221 ? 85 or 75 (for the qualification) for EtG, and m/z 226 ? 208 (for quantification) and 226 ? 75 or 85 (for qualification) for EtG-D5, used as the internal standard. Analyses were carried out using an Inertsil ODS-3 column (100 × 3 mm i.d., 3 µm particle size) and a mobile phase composed of formic acid and acetonitrile. Various SPE cartridges and solvents were tested in order to obtain the highest recoveries and cleanest extracts. The assay linearity of EtG was confirmed over the range from 20 to 2500 pg mg(-1), with a coefficient of determination (R(2) ) above 0.99. The lower limit of quantitation (LLOQ) was 20 pg mg(-1) and the limit of detection was 10 pg mg(-1). Intra- and inter-day assays were less than 15% except at the LLOQ (20%). The analytical method was applied to 72 post-mortem hair samples. EtG concentration in the hair ranged from 0 to 653 pg mg(-1) hair. PMID:22234871

Cabarcos, Pamela; Hassan, Huda M; Tabernero, María Jesús; Scott, Karen S

2012-01-10

49

Development and validation of a gas chromatography-negative chemical ionization tandem mass spectrometry method for the determination of ethyl glucuronide in hair and its application to forensic toxicology.  

PubMed

Ethyl glucuronide (EtG) is a minor and direct metabolite of ethanol. EtG is incorporated into the growing hair allowing retrospective investigation of chronic alcohol abuse. In this study, we report the development and the validation of a method using gas chromatography-negative chemical ionization tandem mass spectrometry (GC-NCI-MS/MS) for the quantification of EtG in hair. EtG was extracted from about 30 mg of hair by aqueous incubation and purified by solid-phase extraction (SPE) using mixed mode extraction cartridges followed by derivation with perfluoropentanoic anhydride (PFPA). The analysis was performed in the selected reaction monitoring (SRM) mode using the transitions m/z 347-->163 (for the quantification) and m/z 347-->119 (for the identification) for EtG, and m/z 352-->163 for EtG-d(5) used as internal standard. For validation, we prepared quality controls (QC) using hair samples taken post mortem from 2 subjects with a known history of alcoholism. These samples were confirmed by a proficiency test with 7 participating laboratories. The assay linearity of EtG was confirmed over the range from 8.4 to 259.4 pg/mg hair, with a coefficient of determination (r(2)) above 0.999. The limit of detection (LOD) was estimated with 3.0 pg/mg. The lower limit of quantification (LLOQ) of the method was fixed at 8.4 pg/mg. Repeatability and intermediate precision (relative standard deviation, RSD%), tested at 4 QC levels, were less than 13.2%. The analytical method was applied to several hair samples obtained from autopsy cases with a history of alcoholism and/or lesions caused by alcohol. EtG concentrations in hair ranged from 60 to 820 pg/mg hair. PMID:19109074

Kharbouche, Hicham; Sporkert, Frank; Troxler, Stéphanie; Augsburger, Marc; Mangin, Patrice; Staub, Christian

2008-12-06

50

Urine tested positive for ethyl glucuronide and ethyl sulfate after the consumption of yeast and sugar  

Microsoft Academic Search

BackgroundTo an increasing degree, EtG and EtS are routinely used for the proof of abstinence for purposes of traffic, occupational, addiction and social medicine. This routine use demands further investigations on the sensitivity and specificity of these analytes and the examination of possible genesis of positive EtG and EtS concentrations even without the consumption of ethanol. In vivo fermentation with

Annette Thierauf; Ariane Wohlfarth; Volker Auwärter; Markus Große Perdekamp; Friedrich Martin Wurst; Wolfgang Weinmann

2010-01-01

51

Chemometric evaluation of nine alcohol biomarkers in a large population of clinically-classified subjects: pre-eminence of ethyl glucuronide concentration in hair for confirmatory classification.  

PubMed

An important goal of forensic and clinical toxicology is to identify biological markers of ethanol consumption that allow an objective diagnosis of chronic alcohol misuse. Blood and head hair samples were collected from 175 subjects-objectively classified as non-drinkers (N=65), social drinkers (N=51) and active heavy drinkers (N=59)-and analyzed to determine eight traditional indirect biomarkers of ethanol consumption [aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyltransferase (?-GT), alkaline phosphatase (ALP), mean corpuscular volume (MCV), carbohydrate-deficient transferrin (CDT), and cholesterol and triglycerides in blood] and one direct biomarker [ethyl glucuronide (EtG) in head hair]. The experimental values obtained from these determinations were submitted to statistical evaluations. In particular, Kruskal-Wallis, Mann-Whitney and ROC curve analyses, together with principal component analysis (PCA), allowed the diagnostic performances of the various biomarkers to be evaluated and compared consistently. From these evaluations, it was possible to deduce that EtG measured in head hair is the only biomarker that can conclusively discriminate active heavy drinkers from social and non-drinkers, using a cut-off value of 30 pg/mg. In contrast, a few indirect biomarkers such as ALP, cholesterol, and triglycerides showed extremely low diagnostic abilities and may convey misleading information. AST and ALT proved to be highly correlated and exhibited quite low sensitivity and specificity. Consequently, either of these parameters can be discarded without compromising the classification efficiency. Among the indirect biomarkers, ?-GT provided the highest diagnostic accuracy, while CDT and MCV yielded high specificity but low sensitivity. It was therefore concluded that EtG in head hair is the only biomarker capable of supporting a confirmatory diagnosis of chronic alcohol abuse in both forensic and clinical practice, while it was found that ?-GT, CDT, MCV, and AST--whether used alone or in combination--do not allow the conclusive classification of subjects according to ethanol consumption. However, a diagnostic strategy combining these four parameters could be formulated in order to create a multivariate model capable of screening suspected active heavy drinkers. PMID:21901464

Pirro, Valentina; Valente, Valeria; Oliveri, Paolo; De Bernardis, Angela; Salomone, Alberto; Vincenti, Marco

2011-09-04

52

Inhibition of bacterial degradation of EtG by collection as dried urine spots (DUS).  

PubMed

Ethyl glucuronide (EtG) and ethyl sulfate (EtS) are direct alcohol consumption markers widely used nowadays for clinical and forensic applications. They are detectable in blood and urine even after consumption of trace amounts of ethanol and for a longer time frame, being detectable even when no more ethanol is present. The instability of EtG against bacterial degradation in contaminated urine samples and/or the possible postcollection synthesis of this metabolite in samples containing, e.g., Escherichia coli and ethanol, may cause false identification of alcohol uptake. Therefore, it is of paramount importance to constrict these error sources by inhibition of any bacterial growth causing hydrolization or synthesis of EtG. This study evaluates a new method of collecting urine samples on filter paper, dried urine spots (DUS), for simultaneous detection of EtG, EtS and creatinine, having the great advantage of inhibiting bacterial activity. In addition, a method validation for the determination of EtG and EtS in DUS was performed according to the FDA guidelines. Sterile-filtered urine was spiked with EtG and EtS, inoculated with E. coli and incubated. Liquid and dried urine samples were collected after various time intervals up to 96 h. Liquid samples were frozen immediately after collection, whereas aliquots for DUS were pipetted onto filter paper, allowed to dry and stored at RT until analysis 1 week after. The specimens were analyzed by LC-ESI-MS/MS. As expected, degradation of EtG, but not of EtS, was observed in contaminated liquid urine samples. However, the specimens collected on filter paper and stored at RT showed no degradation during storage. Therefore, collecting urine samples on filter paper for EtG and EtS analysis turns out to be a reliable method to avoid bacterial degradation of EtG and EtS, and consequently, stabilization of these ethanol metabolites is achieved. In addition, simultaneous measurement of creatinine content as an indicator of urine dilution helps to interpret the results. Method validation for EtG and EtS in DUS was satisfactory, showing the linearity of the calibration curves in the studied concentration range, good precision, accuracy and selectivity. PMID:22249418

Redondo, Ana Hernández; Körber, Christiane; König, Stefan; Längin, Andreas; Al-Ahmad, Ali; Weinmann, Wolfgang

2012-01-17

53

Involvement of UDP-glucuronosyltransferases UGT1A9 and UGT2B7 in ethanol glucuronidation, and interactions with common drugs of abuse.  

PubMed

Ethyl glucuronide (EtG) determination is increasingly used in clinical and forensic toxicology to document ethanol consumption. The enzymes involved in EtG production, as well as potential interactions with common drugs of abuse, have not been extensively studied. Activities of human liver (HLM), kidney (HKM), and intestinal (HIM) microsomes, as well as of 12 major human recombinant UDP-glucuronosyltransferases (UGTs), toward ethanol (50 and 500 mM) were evaluated in vitro using liquid chromatography-tandem mass spectrometry. Enzyme kinetic parameters were determined for pooled microsomes and recombinant UGTs with significant activity. Individual contributions of UGTs were estimated using the relative activity factor approach, proposed for scaling activities obtained with cDNA-expressed enzymes to HLM. Interaction of morphine, codeine, lorazepam, oxazepam, nicotine, cotinine, cannabinol, and cannabidiol (5, 10, 15 mg/l) with ethanol (1.15, 4.6, 11.5 g/l; i.e., 25, 100, 250 mM) glucuronidation was assessed using pooled HLM. Ethanol glucuronidation intrinsic clearance (Cl(int)) was 4 and 12.7 times higher for HLM than for HKM and HIM, respectively. All recombinant UGTs, except UGT1A1, 1A6, and 1A10, produced EtG in detectable amounts. UGT1A9 and 2B7 were the most active enzymes, each accounting for 17 and 33% of HLM Cl(int), respectively. Only cannabinol and cannabidiol significantly affected ethanol glucuronidation. Cannabinol increased ethanol glucuronidation in a concentration-dependent manner, whereas cannabidiol significantly inhibited EtG formation in a noncompetitive manner (IC(50) = 1.17 mg/l; inhibition constant (K(i)) = 3.1 mg/l). UGT1A9 and 2B7 are the main enzymes involved in ethanol glucuronidation. In addition, our results suggest that cannabinol and cannabidiol could significantly alter ethanol glucuronidation. PMID:23230132

Al Saabi, Alaa; Allorge, Delphine; Sauvage, François-Ludovic; Tournel, Gilles; Gaulier, Jean-Michel; Marquet, Pierre; Picard, Nicolas

2012-12-10

54

Forensic confirmatory analysis of ethyl sulfate—A new marker for alcohol consumption—by liquid-chromatography\\/electrospray ionization\\/tandem mass spectrometry  

Microsoft Academic Search

Ethyl sulfate (EtS)—a new direct marker for ethanol intake besides ethyl glucuronide (EtG) and others—was detected in urine\\u000a samples by electrospray ionization tandem mass-spectrometry (LC-ESI-MS\\/MS). Ethyl sulfate sodium salt was used for method\\u000a development, yielding a precursor [M?H]?\\u000a m\\/z 125 and product ions m\\/z 97 [HSO4]? and m\\/z 80 [SO3]?. Pentadeuterated EtS (D5-EtS) was synthesized by esterification of sulfuric acid

Sebastian Dresen; Wolfgang Weinmann; Friedrich Martin Wurst

2004-01-01

55

Gyrokinetic simulations of ETG Turbulence*  

NASA Astrophysics Data System (ADS)

Recent gyrokinetic simulations of electron temperature gradient (ETG) turbulence [1,2] produced different results despite similar plasma parameters. Ref.[1] differs from Ref.[2] in that [1] eliminates magnetically trapped particles ( r/R=0 ), while [2] retains magnetically trapped particles ( r/R 0.18 ). Differences between [1] and [2] have been attributed to insufficient phase-space resolution and novel physics associated with toroidicity and/or global simulations[2]. We have reproduced the results reported in [2] using a flux-tube, particle-in-cell (PIC) code, PG3EQ[3], thereby eliminating global effects as the cause of the discrepancy. We observe late-time decay of ETG turbulence and the steady-state heat transport in agreement with [2], and show this results from discrete particle noise. Discrete particle noise is a numerical artifact, so both the PG3EQ simulations reported here and those reported in Ref.[2] have little to say about steady-state ETG turbulence and the associated anomalous electron heat transport. Our attempts to benchmark PIC and continuum[4] codes at the plasma parameters used in Ref.[2] produced very large, intermittent transport. We will present an alternate benchmark point for ETG turbulence, where several codes reproduce the same transport levels. Parameter scans about this new benchmark point will be used to investigate the parameter dependence of ETG transport and to elucidate saturation mechanisms proposed in Refs.[1,2] and elsewhere[5-7].*In collaboration with A. Dimits (LLNL), J. Candy, C. Estrada-Mila (GA), W. Dorland (U of MD), F. Jenko, T. Dannert (Max-Planck Institut), and G. Hammett (PPPL). Work at LLNL performed for US DOE under Contract W7405-ENG-48.[1] F. Jenko and W. Dorland, PRL 89, 225001 (2002).[2] Z. Lin et al, 2004 Sherwood Mtg.; 2004 TTF Mtg.; Fusion Energy 2004 (IAEA, Vienna, 2005); Bull. Am. Phys. Soc. (November, 2004); 2005 TTF Mtg.; 2005 Sherwood Mtg.; Z. Lin, et al, Phys. Plasmas 12, 056125 (2005). [3] A.M. Dimits, et al, Phys. Rev. Letters 77, 71 (1996).[4] J. Candy, and R.E. Waltz, JCP 186, 5445 (2003); F. Jenko, et al, Phys. Plasmas 7, 1905 (2000).[5] S.C. Cowley, et al, Phys. Fluids B 3, 2767 (1991).[6] C. Holland and P. Diamond, submitted to Physics Letters A (2005).[7] F. Jenko, Theory of Fusion Plasmas (2002).

Nevins, William

2005-10-01

56

A fatal clomipramine intoxication case of a chronic alcoholic patient: application of postmortem hair analysis method of clomipramine and ethyl glucuronide using LC/APCI/MS.  

PubMed

Toxicological investigations of postmortem specimens of a 26-year-old man were performed with the use of LC/APCI/MS. They revealed in the blood of the deceased clomipramine (9.49 microg/g) and its main metabolite norclomipramine (1.10 microg/g) at concentrations explaining the fatal outcome. The presence of these xenobiotics in a 12-cm-long strand of hair (clomipramine, 7.60 ng/mg in I segment; 4.19 ng/mg in II segment; 1.86 ng/mg in III segment; norclomipramine, 5.71 ng/mg in I segment; 9.71 ng/mg in II segment; 4.13 ng/mg in III segment) confirmed the fact obtained from the medical history that the deceased had been receiving clomipramine as an antidepressant for 1 year prior to his death. The analysis demonstrated ethanol in autopsy blood (2.5mg/ml) and urine (3.2mg/ml); ethyl glucuronide as a marker of chronic alcohol abuse was detected in the deceased's hair (0.44 ng/mg in I segment; 0.07 ng/mg in II segment; n.d. in III segment). These findings may suggest the contribution of alcohol in the mechanism of drug-ethanol interaction, which in consequence might have affected the biotransformation of clomipramine in the final period of his life and evoked the ultimate toxic effect. PMID:16046273

K?ys, Ma?gorzata; Scis?owski, Mariusz; Rojek, Sebastian; Ko?odziej, Jan

2005-10-01

57

Experimental Investigation of the ETG Nonlinear Saturation Mechanism  

NASA Astrophysics Data System (ADS)

We have produced and identified the slab electron temperature gradient (ETG) mode in the Columbia Linear Machine (CLM) [1]. Now we investigate the nonlinear saturation mechanism of the ETG modes. We study 3-wave coupling physics via the bi- coherence investigation and find signatures of the interaction between ETG modes and some low frequency modes. The saturation mechanism of the ETG modes is suspected to be related to the damping of low frequency modes. More detailed identification of the low frequency modes including their dispersion will be reported. [4pt] [1] X. Wei, V. Sokolov, A.K. Sen, APS DPP08 TP6.00131

Wei, Xiao; Sokolov, Vladimir; Sen, Amiya K.

2009-11-01

58

Magnetic Secondary Instabilities in ETG Turbulence  

NASA Astrophysics Data System (ADS)

Research in the last decade has established the importance of the ion temperature gradient (ITG) instability in determining ion particle and energy transport. However, understanding of electron transport has not kept pace. The electron temperature gradient (ETG) mode has been proposed as a primary mechanism for electron transport. The possibilities of magnetic secondary instabilities (zonal "fields" and magnetic streamers) are investigated as potential mechanisms for electron transport regulation and enhancement, respectively. The role of adiabatic ions (versus non-adiabatic electrons in ITG turbulence) is discussed, as are the effects of magnetic Reynolds stresses. Growth and damping of both secondary instabilities are discussed. Finally, the effectiveness of random magnetic shearing as a turbulence regulation mechanism, and of magnetic streamers for enhancing transport, are investigated.

Wecht, B.; Holland, C.; Diamond, P. H.

2001-10-01

59

Gyrokinetic Simulations of ETG and ITG Turbulence  

SciTech Connect

Published gyrokinetic continuum-code simulations indicated levels of the electron thermal conductivity {chi}{sub e} due to electron-temperature-gradient (ETG) turbulence large enough to be significant in some tokamaks, while subsequent global particle-in-cell (PIC) simulations gave significantly lower values. We have carried out an investigation of this discrepancy. We have reproduced the key features of the aforementioned PIC simulations using the flux-tube gyrokinetic PIC code, PG3EQ, thereby eliminating global effects and as the cause of the discrepancy. We show that the late-time low-transport state in both of these sets of PIC simulations is a result of discrete particle noise, which is a numerical artifact. Thus, the low value of {chi}{sub e} along with conclusions about anomalous transport drawn from these particular PIC simulations are unjustified. In our attempts to benchmark PIC and continuum codes for ETG turbulence at the plasma parameters used above, both produce very large intermittent transport. We have therefore undertaken benchmarks at an alternate reference point, magnetic shear s=0.1 instead of s=0.796, and have found that PIC and continuum codes reproduce the same transport levels. Scans in the magnetic shear show an abrupt transition to a high-{chi}{sub e} state as the shear is increased above s=0.4. When nonadiabatic ions are used, this abrupt transition is absent, and {chi}{sub e} increases gradually reaching values consistent with transport analyses of DIII-D, JET, and JT60-U discharges. New results on the balances of zonal-flow driving and damping terms in late-time quasi-steady ITG turbulence and on real-geometry gyrokinetic simulations of shaped DIII-D discharges are also reported.

Dimits, A; Nevins, W; Shumaker, D; Hammett, G; Dannert, T; Jenko, F; Dorland, W; Leboeuf, J; Rhodes, T; Candy, J; Estrada-Mila, C

2006-10-03

60

Iso-Glucuronides.  

PubMed

This review on isomers or acyl glucuronides (iso-glucuronides) updates earlier reviews, and attempts to place in context the advances that have been made, especially over the last 15 years. The essential chemistry behind the intramolecular acyl migration and anomerization reactions of acyl glucuronides has been appreciated for 30 years. The great advances in the past 15 years have been in understanding the dynamics and kinetics of these processes in vitro, using highly sophisticated modern technology, e.g. LC-NMR, LC-MS/MS. In this way, earlier assumptions on kinetics and identification of migration isomers and anomers have come under intense review and update. Extensive structure-activity relationships, involving electronic and steric characteristics of an acyl glucuronide and its possible 7 isomers (excluding transient open-chain species) have been delineated. The covalent modification of endogenous proteins and other macromolecules has been further explored, though direct linkage between such modification and toxic sequelae remains elusive. An alternative view of acyl glucuronides and iso-glucuronides as just xenobiotics has perhaps added the dimension that acyl glucuronidation (and attendant formation of iso-glucuronides) does not necessarily mean that glucuronidation of the aglycone has ended metabolic sequences in vivo. PMID:21342113

Dickinson, Ronald G

2011-02-21

61

Iso-glucuronides.  

PubMed

This review on isomers or acyl glucuronides (iso-glucuronides) updates earlier reviews, and attempts to place in context the advances that have been made, especially over the last 15 years. The essential chemistry behind the intramolecular acyl migration and anomerization reactions of acyl glucuronides has been appreciated for 30 years. The great advances in the past 15 years have been in understanding the dynamics and kinetics of these processes in vitro, using highly sophisticated modern technology, e.g. LC-NMR, LC-MS/MS. In this way, earlier assumptions on kinetics and identification of migration isomers and anomers have come under intense review and update. Extensive structure-activity relationships, involving electronic and steric characteristics of an acyl glucuronide and its possible 7 isomers (excluding transient open-chain species) have been delineated. The covalent modification of endogenous proteins and other macromolecules has been further explored, though direct linkage between such modification and toxic sequelae remains elusive. An alternative view of acyl glucuronides and iso-glucuronides as just xenobiotics has perhaps added the dimension that acyl glucuronidation (and attendant formation of iso-glucuronides) does not necessarily mean that glucuronidation of the aglycone has ended metabolic sequences in vivo. PMID:21395535

Dickinson, Ronald G

2011-03-01

62

Direct quantification of steroid glucuronides in human urine by liquid chromatography–electrospray tandem mass spectrometry  

Microsoft Academic Search

A method based on liquid chromatography–tandem mass spectrometry (LC–MS\\/MS) for the direct quantification of glucuronides of testosterone (TG), epitestosterone (EPG), androsterone (AG) and etiocholanolone (ETG) has been developed. The method allowed for the direct determination of these analytes avoiding hydrolysis and derivatization, which are usual steps in commonly used methods based on gas chromatography–mass spectrometry (GC–MS). The electrospray ionization and

Oscar J. Pozo; Peter Van Eenoo; Wim Van Thuyne; Koen Deventer; Frans T. Delbeke

2008-01-01

63

Investigations on ETG turbulence in finite beta plasmas of LVPD  

NASA Astrophysics Data System (ADS)

This paper presents the first controlled observations on electron temperature gradient (ETG) driven turbulence in finite beta (? ˜ 0.6) plasmas of the Large Volume Plasma Device (LVPD). The observed instability is investigated in the core region of the target plasma when a ˜2 m diameter magnetic electron energy filter is used. The observed instability in the lower hybrid range of frequencies has electromagnetic fluctuations associated with it and is characterized by broadband spectra with central frequency, ? ? 10 kHz, and wave number, k? = (0.1-0.2) cm-1, which satisfies the condition k??e ? 1 where ?e is the electron Larmor radius. It is also observed that the observed mode satisfies the condition, k?/k? ? 1. A confirmation of it as ETG turbulence is demonstrated by its absence when ?Te is made vanishingly small.

Singh, S. K.; Awasthi, L. M.; Mattoo, S. K.; Srivastava, P. K.; Singh, R.; Kaw, P. K.

2012-12-01

64

Role of stable eignmodes in ETG-driven turbulence  

NASA Astrophysics Data System (ADS)

We investigate the role of the stable eigenmodes in the electron-temperature-gradient driven (ETG) turbulence. The low-wavenumber stable eigenmodes are thought to play a role in the dissipation mechanism leading to the saturation of CTEM [1] and ITG [2] turbulence. Based on the ETG slab fluid model [3], the condition and parameter regime for the saturation by the stable mode are analytically explored through statistical closure theory. In the simulation, the evolution of heat flux and turbulent energy are traced with the correlation of the stable and unstable modes. Possible effect of the stable mode saturation on zonal flow and magnetic fluctuation will be discussed. In the future, we will extend the analysis to the nonlocal ETG fluid model and kinetic model. [1] P. W. Terry, D. A. Baver, and S. Gupta, Phys. Plasmas 13, 022307 (2006). [2] R. Gatto, P. W. Terry, and D. A. Baver, Phys. Plasmas 13, 022306 (2006). [3] W. Horton et. al. Nuclear Fusion 45 (2005).

Kim, Juhyung; Terry, Paul W.

2008-11-01

65

The muramidase EtgA from enteropathogenic Escherichia coli is required for efficient type III secretion.  

PubMed

Enteropathogenic Escherichia coli (EPEC) is an important cause of infectious diarrhoea. It colonizes human intestinal epithelial cells by delivering effector proteins into the host cell cytoplasm via a type III secretion system (T3SS) encoded within the chromosomal locus of enterocyte effacement (LEE). The LEE pathogenicity island also encodes a lytic transglycosylase (LT) homologue named EtgA. In the present work we investigated the significance of EtgA function in type III secretion (T3S). Purified recombinant EtgA was found to have peptidoglycan lytic activity in vitro. Consistent with this function, signal peptide processing and bacterial cell fractionation revealed that EtgA is a periplasmic protein. EtgA possesses the conserved glutamate characteristic of the LT family, and we show here that it is essential for enzymic activity. Overproduction of EtgA in EPEC inhibits bacterial growth and induces cell lysis unless the predicted catalytic glutamate is mutated. An etgA mutant is attenuated for T3S, red blood cell haemolysis and EspA filamentation. BfpH, a plasmid-encoded putative LT, was not able to functionally replace EtgA. Overall, our results indicate that the muramidase activity of EtgA is not critical but makes a significant contribution to the efficiency of the T3S process. PMID:21233160

García-Gómez, Elizabeth; Espinosa, Norma; de la Mora, Javier; Dreyfus, Georges; González-Pedrajo, Bertha

2011-01-13

66

Autism and phthalate metabolite glucuronidation.  

PubMed

Exposure to environmental chemicals may precipitate autism spectrum disorders (ASD) in genetically susceptible children. Differences in the efficiency of the glucuronidation process may substantially modulate substrate concentrations and effects. To determine whether the efficiency of this pathway is compromised in children with ASD, we measured the efficiency of glucuronidation for a series of metabolites derived from the commonly used plasticizer, diethylhexyl phthalate. Spot urines were collected and analyzed for the fraction of each metabolite conjugated by isotope dilution-liquid chromatography mass spectrometry-mass spectrometry. The degree of glucuronidation was lower with the ASD group. The glucuronidation pathway may differ in some children with ASD. PMID:23575644

Stein, T Peter; Schluter, Margaret D; Steer, Robert A; Ming, Xue

2013-11-01

67

CURRENT ASPECTS OF ASSET MANAGEMENT WITHIN ROMANIA'S ELECTRICITY TRANSMISSION GRID (ETG) AS CRITICAL INFRASTRUCTURE  

Microsoft Academic Search

The National Power Grid Company Transelectrica SA is the national transmission and system operator (TSO) providing regulated, transparent and non-discriminating access to the infrastructure of the electricity market represented by the transmission grid (ETG), as well as the operational control of the Romanian Power System (RPS) according to the quality, safety and efficiency rules provided in the ETG Technical code.

Ciprian DIACONU; Marian FLOREA; Christiana BARBULESCU

68

Dynamics of Secondary Large-Scale Structures in ETG Turbulence Simulations  

NASA Astrophysics Data System (ADS)

The dynamics of secondary large-scale structures in electron-temperature-gradient (ETG) turbulence is investigated based on gyrofluid simulations in sheared slab geometry. It is found that structural bifurcation to zonal flow dominated or streamer-like states depends on the spectral anisotropy of turbulent ETG fluctuation, which is governed by the magnetic shear. The turbulent electron transport is suppressed by enhanced zonal flows. However, it is still low even if the streamer is formed in ETG turbulence with strong shears. It is shown that the low transport may be related to the secondary excitation of poloidal long-wavelength mode due to the beat wave of the most unstable components or a modulation instability. This large-scale structure with a low frequency and a long wavelength may saturate, or at least contribute to the saturation of ETG fluctuations through a poloidal mode coupling. The result suggests a low fluctuation level in ETG turbulence.

Li, Jiquan; Y, Kishimoto; Dong, Jiaqi; N, Miyato; T, Matsumoto

2006-01-01

69

Different Electrostatic Potentials Define ETGE and DLG Motifs as Hinge and Latch in Oxidative Stress Response  

Microsoft Academic Search

Nrf2 is the regulator of the oxidative\\/electrophilic stress response. Its turnover is maintained by Keap1- mediated proteasomal degradation via a two-site substrate recognition mechanism in which two Nrf2-Keap1 binding sites form a hinge and latch. The E3 ligase adaptor Keap1 recognizes Nrf2 through its conserved ETGE and DLG motifs. In this study, we examined how the ETGE and DLG motifs

Kit I. Tong; Balasundaram Padmanabhan; Akira Kobayashi; Chengwei Shang; Yosuke Hirotsu; Shigeyuki Yokoyama; Masayuki Yamamoto

2007-01-01

70

Role of stable eignmodes in 3D ETG-driven turbulence  

NASA Astrophysics Data System (ADS)

The role of stable eigenmodes in Electron-Temperature-Gradient driven (ETG) turbulence is investigated. Low-wavenumber stable eigenmodes are thought to play a role in the dissipation mechanism leading to saturation of CTEM[1] and ITG[2] turbulence. Evidence has been found that the formation of magnetic coherent structures and the transition to a turbulence regime with stronger magnetic fluctuations are dependent of the ETG low k stable modes in 2D fixed-kz fluid simulations[3]. A 3D code has been constructed to investigate the role of stable modes in 3D sheared slab geometry. Magnetic structure formation and electromagnetic ETG turbulence will be discussed in detail. [1] P. W. Terry, D. A. Baver and S. Gupta, Phys. Plasmas 13, 022307 (2006). [2] R. Gatto, P. W. Terry and D. A. Baver, Phys. Plasmas 13 022306 (2006). [3] J.-H. Kim and P. W. Terry (2008), 50th Annual Meeting of the Division of Plasma Physics, APS.

Kim, Juhyung; Terry, Paul W.

2009-05-01

71

Determination of testosterone and epitestosterone glucuronides in urine by ultra performance liquid chromatography-ion mobility-mass spectrometry.  

PubMed

UPLC-ion mobility spectrometry separations combined with mass spectrometry (UPLC-IM-MS) and tandem mass spectrometry (UPLC-IM-MS/MS) have been investigated for the simultaneous determination of testosterone and epitestosterone glucuronides in urine. The glucuronide epimers of testosterone and epitestosterone were separated by ion mobility spectrometry prior to mass analysis on the basis of differences in their collision cross sections, which have been measured in nitrogen. Combining ion mobility separation with UPLC/MS enhances the analysis of these low-abundance steroids in urine by selective interrogation of specific retention time, mass-to-charge and mobility regions. Detection limits for the UPLC-IM-MS/MS analysis of TG and ETG were 9.9 ng mL(-1) and 98 ng mL(-1) respectively, equivalent to 0.7 ng mL(-1) and 7.4 ng mL(-1) in urine, with linear dynamic ranges corresponding to 0.7-108 ng mL(-1) and 7.4-147 ng mL(-1) in urine. Repeatability (%RSD) for urine extracts was 0.64% and 2.31% for TG and ETG respectively. PMID:21842047

Kaur-Atwal, Gushinder; Reynolds, James C; Mussell, Christopher; Champarnaud, Elodie; Knapman, Tom W; Ashcroft, Alison E; O'Connor, Gavin; Christie, Steven D R; Creaser, Colin S

2011-08-12

72

Search for TEM and ETG Modes with the Upgraded PCI Diagnostic in Alcator C-Mod  

NASA Astrophysics Data System (ADS)

Phase Contrast Imaging (PCI) diagnostic has been used in the past to study turbulent density fluctuations up to 500 kHz(A. Mazurenko et al, Phys. Rev. Letts. 89), 225004 (2002). and coherent RF waves(E. Nelson-Melby et al, Phys. Rev. Letts. 90), 155004 (2003).. Recently, the PCI diagnostic has been upgraded from 12 to 32 channels with frequency response up to 10 MHz, which makes the direct study of microscale turbulence possible. Detailed microstability analysis of typical C-Mod plasmas with the gyrokinetic code GS2 yields candidate discharges in which ETG and/or TEM modes are unstable. C-Mod EDA H-Mode discharges, likely candidates for unstable ETG modes, are first surveyed using a parameterization of the ETG critical gradient(F. Jenko et al, Phys. Plasmas 8), 4096 (2001).. Possible regimes for TEM include the ITB(D. R. Ernst et al, Phys. Plasmas 11), 2637 (2004). and L-Mode discharges. Radial ETG streamers predicted in gyrokinetic simulations(W. Dorland et al, Phys. Rev. Letts. 85), 5579 (2000). will also be explored.

Lin, L.; Porkolab, M.; Ernst, D. R.; Basse, N. P.; Edlund, E. M.; Fiore, C. L.; Lin, Y.; Wukitch, S. J.

2004-11-01

73

Different Electrostatic Potentials Define ETGE and DLG Motifs as Hinge and Latch in Oxidative Stress Response?  

PubMed Central

Nrf2 is the regulator of the oxidative/electrophilic stress response. Its turnover is maintained by Keap1-mediated proteasomal degradation via a two-site substrate recognition mechanism in which two Nrf2-Keap1 binding sites form a hinge and latch. The E3 ligase adaptor Keap1 recognizes Nrf2 through its conserved ETGE and DLG motifs. In this study, we examined how the ETGE and DLG motifs bind to Keap1 in a very similar fashion but with different binding affinities by comparing the crystal complex of a Keap1-DC domain-DLG peptide with that of a Keap1-DC domain-ETGE peptide. We found that these two motifs interact with the same basic surface of either Keap1-DC domain of the Keap1 homodimer. The DLG motif works to correctly position the lysines within the Nrf2 Neh2 domain for efficient ubiquitination. Together with the results from calorimetric and functional studies, we conclude that different electrostatic potentials primarily define the ETGE and DLG motifs as a hinge and latch that senses the oxidative/electrophilic stress.

Tong, Kit I.; Padmanabhan, Balasundaram; Kobayashi, Akira; Shang, Chengwei; Hirotsu, Yosuke; Yokoyama, Shigeyuki; Yamamoto, Masayuki

2007-01-01

74

Selenide isotope generator for the Galileo mission. ETG acceptance test plan  

SciTech Connect

Electrically-Heated Thermoelectric Generators (ETGs) shall be subjected to a flight level acceptance test program to certify the design of the SIG/Galileo flight generator. Each test in the test program is designed to simulate critical conditions and environments associated with generator ground handling, spacecraft launch and in-space operations. Successful completion of the test program shall be evidenced by the satisfactory performance of the ETG during and after the application of the various test environments. The ETG Acceptance Test Plan is designed to specify the testing sequence, the severity of the applied test environments and the acceptance criteria for assessing generator performance. Two test facilities shall be required for the execution of the proposed test program. The Teledyne Energy Systems (TES) facility in Timonium, Maryland shall be the site for the ETG thermal performance evaluation testing; and the Naval Surface Weapons Center (NSWC) facility in White Oak, Maryland, shall be the site of the dynamic, mass-properties and magnetic properties testing.

Not Available

1978-12-01

75

Scintigraphic imaging with a peptide glucuronide in rabbits: 99mTc exorphin C glucuronide  

Microsoft Academic Search

A peptide glucuronide (Exorphin C glucuronide) was labeled with 99mTc using glucoheptonate (GH) as a bifunctional chelating agent. Scintigraphic imaging was performed in male Albino rabbits. Exorphin C glucuronide showed rapid and efficient labeling with 99mTc using glucoheptonate as a bifunctional chelate. Results demonstrated that 99mTc-GEG may be a useful new type of glucuronide derivative of peptides for diagnosis of

T. Ertay; P. Ünak; F. Z. Biber; C. Tasc?; F. Zihnio?lu; H. Durak

2007-01-01

76

Enhanced clearance of topoisomerase I inhibitors from human colon cancer cells by glucuronidation.  

PubMed

As part of a program to identify novel mechanisms of resistance to topoisomerase I (topo I) inhibitors, the cellular pharmacology of 7-ethyl-10-hydroxycamptothecin (SN-38), the active metabolite of clinically used irinotecan (CPT-11) and NU/ICRF 505, an anthraquinone-tyrosine conjugate, has been investigated in two human colorectal cancer (CRC) cell lines. Two novel metabolites of NU/ICRF 505 (M1 and M2) and a single metabolite of SN-38 (M1) were detected by high performance liquid chromatography in the culture medium of HT29 cells but were absent in HCT116 cells. Identities of all three metabolites were established by a combination of biochemical and physicochemical techniques. M1 of SN-38 was the C10-(beta)-glucuronide of the parent lactone while M1 of NU/ICRF 505 was the C4-O-glucuronide and M2 the tyrosine-O-glucuronide, both of the parent compound. Drug transport studies revealed that by 24hr HT29 cells had effectively cleared 82.5% of NU/ICRF 505 (10 microM) into the culture medium as the two glucuronides. In contrast, intracellular concentrations of NU/ICRF 505 were maintained in HCT116 cells in the absence of glucuronidation at a level 550 times greater than in HT29 cells. HT29 cells cleared 40.9% of SN-38 (1 microM) as the glucuronide to the culture medium, while the parent drug was maintained at a level 2-fold greater in HCT116 cells. Enhanced drug clearance due to glucuronidation may contribute to intrinsic drug resistance of human CRC. PMID:11992628

Cummings, Jeffrey; Boyd, Gary; Ethell, Brian T; Macpherson, Janet S; Burchell, Brian; Smyth, John F; Jodrell, Duncan I

2002-02-15

77

Phenotype-genotype correlation of in vitro SN38 (active metabolite of irinotecan) and bilirubin glucuronidation in human liver tissue with UGT1A1 promoter polymorphism  

Microsoft Academic Search

Background: Hepatic uridine diphosphate glucuronosyltransferase (UGT) isoform 1A1 (UGT1A1) is primarily responsible for the glucuronidation of SN-38 (7-ethyl-10-hydroxycamptothecin), the active metabolite of the anticancer agent irinotecan. UGT1A1, also catalyzing the glucuronidation of bilirubin, has been shown to have reduced activity in Gilbert's syndrome. The presence of an additional TA repeat [(TA)7 TAA] in the TATA sequence of UGT1A1 has been

Lalitha Iyer; Diana Hall; Soma Das; Melissa A. Mortell; Jacqueline Ramírez; Sarang Kim; Anna Di Rienzo; Mark J. Ratain

1999-01-01

78

Lithocholate glucuronide is a cholestatic agent.  

PubMed Central

Lithocholic acid and its taurine, glycine, and sulfate derivatives are potent cholestatic agents. Lithocholate glucuronide is present in the plasma and urine of patients with cholestatic syndromes, but little is known of its metabolism, excretion, and cholestatic potential. [3 beta-3H]lithocholate 3-O-beta-D-glucuronide was synthesized, and chemical and radiochemical purity were established. The aqueous solubility of lithocholate glucuronide was determined and found to be greater than that of lithocholic acid or several of its derivatives. In the range of concentrations examined, calcium ions precipitated lithocholate glucuronide stoichiometrically. The material was administered to rats prepared with an external biliary fistula. When 17-25 micrograms quantities were administered, 89.1 +/- 4.5% (mean +/- SEM) of the radiolabel was secreted in bile within the first 20 h after administration, the major fraction being secreted in less than 20 min. Four-fifths of the radiolabeled material in bile was the administered unaltered parent compound, while a minor fraction consisted of a more polar derivative(s). We showed that increasing biliary concentrations of more polar derivatives were observed with milligram doses of [3H]lithocholate glucuronide, and with time after the administration of these loading doses. Milligram doses of [3H]lithocholate glucuronide resulted in partial or complete cholestasis. When induced cholestasis was partial, secretion in bile remained the primary excretory route (82.5-105.6% recovery in bile), while, when complete cholestasis was induced, wide tissue distribution of radiolabel was observed. Cholestasis developed rapidly during infusion of [3H]lithocholate glucuronide. Bile flow was diminished within 10-20 min of the start of an infusion of 0.05 mumol, 100 g-1 body weight, minute-1, administered concomitantly with an equimolar infusion of taurocholate. The results establish that lithocholate glucuronide exerts cholestatic effects comparable to those exerted by unconjugated lithocholic acid. Images

Oelberg, D G; Chari, M V; Little, J M; Adcock, E W; Lester, R

1984-01-01

79

Measurement of Radial Electron Thermal Transport due to ETG Modes in a Basic Experiment  

NASA Astrophysics Data System (ADS)

Production and identification of electron temperature gradient (ETG) mode have been successfully demonstrated in a basic experiment in Columbia Linear Machine CLM [1]. Using a dc bias heating scheme of the core plasma, we are able to produce sufficiently strong ETG modes in CLM experiments. A unique miniature triple probe was used for local measurement of electron temperature and plasma potential fluctuations. Their cross-correlation yields the local radial electron thermal flux. A preliminary measurement of electron thermal conductivity indicates ?e is about ˜3 m^2/s ˜10 ?e,GB. This result appears to agree with a value of non-local thermal conductivity obtained from a rough theoretical estimation [2]. This research was supported by U.S. Department of Energy Grant No. DE-FG02-98ER-54464. [4pt] [1] X. Wei, V. Sokolov and A.K. Sen, Phys. Plasmas, 17, 042108 (2010). [0pt] [2] H.L. Berk et al, Nucl. Fusion, 33, 263 (1993).

Sokolov, Vladimir; Sen, Amiya

2010-11-01

80

N-Glucuronidation of the antiepileptic drug retigabine: results from studies with human volunteers, heterologously expressed human UGTs, human liver, kidney, and liver microsomal membranes of Crigler-Najjar type II  

Microsoft Academic Search

Retigabine (D-23129), an N-2-amino-4-(4-fluorobenzylamino)phenylcarbamine acid ethyl ester, is a novel antiepileptic drug which is currently in phase II clinical development. This drug undergoes N-glucuronidation. We aimed to identify the principal enzymes involved in the N-glucuronidation pathway of retigabine and compared our findings with those obtained from human liver (a pool of 30 donors) and kidney microsomes (a pool of 3

Jürgen Borlak; Antje Gasparic; Mathias Locher; Hubert Schupke; Robert Hermann

2006-01-01

81

Measurement of direct ethanol metabolites in a case of a former driving under the influence (DUI) of alcohol offender, now claiming abstinence  

Microsoft Academic Search

A 37-year-old female subject had been convicted of driving under the influence of alcohol, and 19 months later, claimed abstinence\\u000a after supervised disulfiram treatment. Our aim was to elucidate the value of direct ethanol metabolites as measures of abstinence.\\u000a Ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEE) in hair, phosphatidylethanol in whole blood and EtG and ethyl sulphate\\u000a in urine

Friedrich M. Wurst; Michel Yegles; Christer Alling; Steina Aradottir; Jutta Dierkes; Gerhard A. Wiesbeck; Claudia C. Halter; Fritz Pragst; Volker Auwaerter

2008-01-01

82

Microsomal hydroxylation and glucuronidation of [6]-gingerol.  

PubMed

[6]-Gingerol is the major pungent principle of ginger and frequently is ingested with various condiments and nutritional supplements. We report here that incubation of [6]-gingerol with NADPH-fortified rat hepatic microsomes gave rise to eight metabolites, which were tentatively identified by GC-MS analysis as two products of aromatic hydroxylation as well as the diastereomers of two aliphatic hydroxylation products and the diastereomers of [6]-gingerdiol. Hepatic microsomes from rats and humans fortified with UDPGA glucuronidated [6]-gingerol predominantly at the phenolic hydroxyl group, but small amounts of a second monoglucuronide involving the aliphatic hydroxyl group were also identified by LC-MS/MS analysis. Human intestinal microsomes formed the phenolic glucuronide only. Supersomes containing human UGT1A1 and 1A3 exclusively generated the phenolic glucuronide, albeit with very low activities, whereas UGT1A9 catalyzed the specific formation of the alcoholic glucuronide and UGT2B7 the predominant formation of the phenolic glucuronide with high activities. Our study indicates a rather complex metabolism of [6]-gingerol, which should be taken into consideration for the multiple biological activities of this compound. PMID:17090120

Pfeiffer, Erika; Heuschmid, Franziska F; Kranz, Stefan; Metzler, Manfred

2006-11-15

83

Glucuronides from metabolites to medicines: a survey of the in vivo generation, chemical synthesis and properties of glucuronides.  

PubMed

Covering: 1998 to 2011. Previous review: Nat. Prod. Rep., 1998, 15, 173-186. The fourteen years that have passed since the previous review on this topic have seen a significant increase of interest in many aspects of glucuronide chemistry and biology. Glucuronides are the most important class of phase 2 xenobiotic metabolites and typically act in a detoxifying role. While this is generally true for O-alkyl and O-aryl glucuronides, a number of glucuronides are known to be pharmacologically active per se. Additionally the use of glucuronide prodrugs, notably to ameliorate the cytotoxicity of anticancer agents, has markedly increased. Whereas the previous review covered only the synthesis of O-glucuronides, we now include N-, S- and C-glucuronides also and discuss both synthetic and biological aspects. Synthetic methods for all classes of glucuronides are reviewed and updated, together with advances in the enzymatic synthesis of glucuronides and methods for their detection. Finally we discuss the biological reactivity of glucuronides where known, including the important morphine-6-glucuronide. A lively debate has continued for several years on whether O-acyl glucuronide metabolites of carboxylic acids are toxic, affecting both the safety assessment of well-used drugs and new drug development programmes. We summarise the current understanding, together with other known examples of interaction between glucuronides and macromolecules. PMID:23648894

Stachulski, Andrew V; Meng, Xiaoli

2013-06-01

84

Inhibition of ciramadol glucuronidation by benzodiazepines.  

PubMed

Studies on the inhibition of ciramadol glucuronidation by benzodiazepines were performed in vitro and in vivo. Ciramadol glucuronidation was slower (Vmax, 1.56 vs. 5.40 nmol/min/mg of microsomal protein) in human than in dog liver microsomes. Inhibition constants (Ki) for lorazepam and oxazepam were 3 to 4 times higher than that calculated for diazepam. Rates of morphine glucuronidation in human liver microsomes were assessed for comparative purposes and agreed with literature values. Each benzodiazepine appeared to be a competitive inhibitor of ciramadol and morphine UDP-glucuronyltransferase activity. The in vivo disposition of ciramadol was unchanged in dogs pretreated with lorazepam. After diazepam treatment no change in the Vdss of ciramadol occurred, but plasma clearance was significantly reduced, resulting in a prolongation of t1/2. Diazepam caused a significant reduction in the oral clearance of ciramadol, whereas no change occurred in systemic availability. Thus, diazepam may have had a secondary effect on hepatic blood flow (QH) and produced offsetting alterations in both intrinsic clearance (Cl int) and QH. A decrease in the area under the plasma concentration time curves of ciramadol aryl O-glucuronide following iv treatment with diazepam coupled with the in vitro data indicate that the mechanism for the decrease in the clearance of ciramadol is inhibition of its glucuronidation by diazepam. Since glucuronidation plays a major role in the elimination of ciramadol in man and dog, these experiments suggest that the disposition of ciramadol in man would not be affected by coadministration of lorazepam, whereas the potential for a diazepam/ciramadol drug interaction in humans exists. PMID:2873990

Meacham, R H; Sisenwine, S F; Liu, A L; Kick, C J; Barinov, I; Ruelius, H W

85

The small intestine can both absorb and glucuronidate luminal flavonoids  

Microsoft Academic Search

We have studied the perfusion of the jejunum and ileum in an isolated rat intestine model with flavonoids and hydroxycinnamates and the influence of glycosylation on the subsequent metabolism. Flavone and flavonol glucosides and their corresponding aglycones are glucuronidated during transfer across the rat jejunum and ileum and this glucuronidation occurs without the need for gut microflora. Furthermore, this suggests

Jeremy P. E Spencer; George Chowrimootoo; Ruksana Choudhury; Edward S Debnam; S. Kaila Srai; Catherine Rice-Evans

1999-01-01

86

The pharmacokinetics of morphine and morphine glucuronides in kidney failure.  

PubMed

The pharmacokinetics of morphine and its glucuronide metabolites were investigated in three groups of patients with kidney failure (nondialyzed, receiving dialysis, and transplantation) and compared with a group of normal healthy volunteers. Patients in all three renal groups were undergoing surgical procedures (nondialyzed group undergoing arteriovenous fistula formation, dialysis group undergoing placement of a peritoneal dialysis catheter, and the transplant group undergoing live donor kidney transplant). A sensitive, specific high-performance liquid chromatographic assay was used to quantitate morphine, morphine-3-glucuronide, and morphine-6-glucuronide. Patients with kidney failure had a significantly increased morphine area under the curve (AUC) compared with control subjects. There was also an increase in the metabolites morphine-3-glucuronide and morphine-6-glucuronide that was severalfold greater than the increase in morphine AUC. This metabolite accumulation was reversed by kidney transplantation, providing an elegant confirmation on the role of the kidney in morphine pharmacology. PMID:8354025

Osborne, R; Joel, S; Grebenik, K; Trew, D; Slevin, M

1993-08-01

87

Investigation of Immobilized Enzymes for Hydrolysis of Glucuronides in Urine.  

National Technical Information Service (NTIS)

Metabolism of certain drugs leads to the formation of conjugation products with glucuronic acid prior to excretion in urine. Thus, heroin is converted to morphine, which after conjugation with glucuronic acid, appears in the urine as morphine glucuronide....

D. J. Fink M. K. Bean R. D. Falb

1975-01-01

88

Diagnosis of chronic alcohol consumption  

Microsoft Academic Search

This paper describes a procedure for the detection and quantification of ethyl-glucuronide (EtG) in hair samples. During method development the efficacy of extraction of EtG from hair was compared in four extraction methods: (a) methanol; (b) methanol:water (1:1); (c) water; and (d) water:trifluoroacetic acid (9:1). In addition, three derivatizing agents were compared as well: N,O-bistrimethylsilyl-trifluoroacetamide (BSTFA): trimethylchlorosilane (TMCS) (99:1), pentafluoropropionic

C. Jurado; T. Soriano; M. P. Giménez; M. Menéndez

2004-01-01

89

Testosterone sulphation and glucuronidation in the human liver: interindividual variability  

Microsoft Academic Search

Summary  Presystemic sulphation and glucuronidation at OH-C17 limits the bioavailability of testosterone; the aim of this investigation was to describe the variability in testosterone\\u000a sulphation and glucuronidation rates in the human liver. Liver samples were obtained from 61 women and 40 men of similar age\\u000a (mean 53 and 55 yers, respectively) submitted to surgery. The mean rate of testosterone sulphation was

Gian Maria Pacifici; A. Gucci; L. Giuliani

1997-01-01

90

Hepatic UDP-glucuronosyltransferase is responsible for eslicarbazepine glucuronidation.  

PubMed

Eslicarbazepine acetate (ESL) is a once-daily novel antiepileptic drug approved in Europe for use as adjunctive therapy for refractory partial-onset seizures with or without secondary generalization. Metabolism of ESL consists primarily of hydrolysis to eslicarbazepine, which is then subject to glucuronidation followed by renal excretion. In this study, we have identified that human liver microsomes (HLM) enriched with uridine 5'-diphosphoglucuronic acid give origin to a single Escherichia coli ?-glucuronidase-sensitive eslicarbazepine glucuronide (most likely the O-glucuronide). The kinetics of eslicarbazepine glucuronidation in HLM was investigated in the presence and absence of bovine serum albumin (BSA). The apparent K(m) were 412.2 ± 63.8 and 349.7 ± 74.3 ?M in the presence and absence of BSA, respectively. Incubations with recombinant human UDP glucuronosyltransferases (UGTs) indicated that UGT1A4, UGT1A9, UGT2B4, UGT2B7, and UGT2B17 appear to be involved in eslicarbazepine conjugation. The UGT with the highest affinity for conjugation was UGT2B4 (K(m) = 157.0 ± 31.2 and 28.7 ± 10.1 ?M, in the absence and presence of BSA, respectively). There was a significant correlation between eslicarbazepine glucuronidation and trifluoperazine glucuronidation, a typical UGT1A4 substrate; however, no correlation was found with typical substrates for UGT1A1 and UGT1A9. Diclofenac inhibited eslicarbazepine glucuronidation in HLM with an IC(50) value of 17 ?M. In conclusion, glucuronidation of eslicarbazepine results from the contribution of UGT1A4, UGT1A9, UGT2B4, UGT2B7, and UGT2B17, but the high-affinity component of the UGT2B4 isozyme may play a major role at therapeutic plasma concentrations of unbound eslicarbazepine. PMID:21673130

Loureiro, Ana I; Fernandes-Lopes, Carlos; Bonifácio, Maria J; Wright, Lyndon C; Soares-da-Silva, Patricio

2011-06-14

91

Stereoselective glucuronidation of formoterol by human liver microsomes  

PubMed Central

Aims Formoterol is a ?2-adrenoceptor agonist marketed as a racemic mixture of the active (R; R)- and inactive (S; S)-enantiomers (rac-formoterol). The drug produces prolonged bronchodilation by inhalation but there is significant interpatient variability in duration of effect. Previous work has shown that in humans formoterol is metabolized by conjugation with glucuronic acid but little is known about the stereoselectivity of this reaction. The aim of the present study was to investigate the glucuronidation of formoterol enantiomers in vitro by human liver microsomes. Methods The kinetics of formation of formoterol glucuronides during incubation of racemate and of single formoterol enantiomers with human liver microsomes (n = 9) was characterized by chiral h.p.l.c. assay. Results The kinetics of glucuronidation of the two formoterol enantiomers obeyed the Michaelis-Menten equation. Glucuronidation of formoterol was stereoselective and occurred more than two times faster for (S; S)-formoterol than for (R; R)-formoterol. In incubations with single formoterol enantiomers, the median (n = 9) Km values for (R; R)-glucuronide and (S; S)-glucuronide were 827.6 and 840.4 ?m, respectively, and the median Vmax values were 2625 and 4304 pmol min?1 mg?1, respectively. Corresponding values determined in incubations with rac-formoterol were 357.2 and 312.1 ?m and 1435 and 2086 pmol min?1 mg?1 for (R; R)- and (S; S)-glucuronide, respectively. Interindividual variation was large with the ratio of Vmax/Km (S; S/R; R) ranging from 0.57 to 6.90 for incubations with rac-formoterol. Conclusions Our study demonstrates that glucuronidation of formoterol by human liver microsomes is stereoselective and subject to high interindividual variability. These findings suggest that clearance of formoterol in humans is subject to variable stereoselectivity which could explain the variation in duration of bronchodilation produced by inhaled formoterol in patients with asthma.

Zhang, Mei; Fawcett, J Paul; Kennedy, Julia M; Shaw, John P

2000-01-01

92

Analgesic responses to intrathecal morphine in relation to CSF concentrations of morphine-3,?-glucuronide and morphine-6,?-glucuronide  

Microsoft Academic Search

This study was performed to determine whether variations in analgesic responses to intrathecal morphine could be explained by cerebrospinal fluid (CSF) concentrations of morphine metabolites. Twenty-four CSF samples were collected at the beginning, middle and end of treatment periods in seven cancer patients with pain of malignant origin. CSF concentrations of morphine-3,?-glucuronide (M3G) and morphine-6,?-glucuronide (M6G) metabolites were measured by

Gary C. Dennis; Deepa Soni; Ozra Dehkordi; Richard M. Millis; Hutchinson James; William L. West; Robert E. Taylor

1999-01-01

93

N-glucuronidation of drugs and other xenobiotics by human and animal UDP-glucuronosyltransferases.  

PubMed

Metabolic disposition of drugs and other xenobiotics includes glucuronidation reactions that are catalyzed by the uridine diphosphate glucuronosyltransferases (UGTs). The most common glucuronidation reactions are O- and N-glucuronidation and in this review, we discuss both, while the emphasis is on N-glucuronidation. Interspecies difference in glucuronidation is another central issue in this review due to its importance in drug development. Accordingly, the available data on glucuronidation in different animals comes mainly from the species that are used in preclinical studies to assess the safety of drugs under development. Both O- and N-glucuronidation reactions are chemically diverse. Different O-glucuronidation reactions are described and discussed, and many drugs that undergo such reactions are indicated. The compounds that undergo N-glucuronidation include primary aromatic amines, hydroxylamines, amides, tertiary aliphatic amines, and aromatic N-heterocycles. The interspecies variability in N-glucuronidation is particularly high, above all when it comes to aliphatic tertiary amines and aromatic N-heterocycles. The N-glucuronidation rates in humans are typically much higher than in animals, largely due to the activity of two enzymes, the extensively studied UGT1A4, and the more recently identified as a main player in N-glucuronidation, UGT2B10. We discuss both enzymes and review the findings that revealed the role of UGT2B10 in N-glucuronidation. PMID:21434773

Kaivosaari, Sanna; Finel, Moshe; Koskinen, Mikko

2011-03-24

94

ETHYL GLUCURONIDE: A BIOMARKER TO IDENTIFY ALCOHOL USE BY HEALTH PROFESSIONALS RECOVERING FROM SUBSTANCE USE DISORDERS  

Microsoft Academic Search

Aims: Physicians recovering from substance-related disorders are usually allowed to return to practice if they agree to remain abstinent from drugs, including alcohol, and to undergo random urine testing. Over 9000 physicians are currently involved in such monitoring programs in the US. To date, it has been difficult to adequately monitor abstinence from alcohol due to the short half- life

GREGORY E. SKIPPER; WOLFGANG WEINMANN; ANNETTE THIERAUF; PATRICK SCHAEFER; GERHARD WIESBECK; JOHN P ALLEN; MICHAEL MILLER; FRIEDRICH MARTIN WURST

95

Testosterone sulphation and glucuronidation in the human liver: interindividual variability.  

PubMed

Presystemic sulphation and glucuronidation at OH-C17 limits the bioavailability of testosterone; the aim of this investigation was to describe the variability in testosterone sulphation and glucuronidation rates in the human liver. Liver samples were obtained from 61 women and 40 men of similar age (mean 53 and 55 years, respectively) submitted to surgery. The mean rate of testosterone sulphation was significantly (P = 0.002) higher in men (22.4 pmol/min/mg) than in women (17.5 pmol/min/mg), was not age-dependent, followed bimodal distribution and varied over 7-fold in men and women. There was a weak, but significant negative correlation (r = -0.380; P = 0.003), between the rate of testosterone glucuronidation and age in the liver of women but not in that of men. The mean rate (pmol/min/mg) of testosterone glucuronidation was 155 (men) and 105 (women) (NS) and varied over 20-fold. When the rate of testosterone glucuronidation was expressed on the basis of g liver equivalent, the mean estimates were significantly (P = 0.003) greater in men (3323 pmol/min/g) than in women (1841 pmol/min/g). The present findings are consistent with the view that the hepatic activities of sulphotransferase and glucuronosyltransferase are higher in men than in women and that they vary in the human liver. PMID:9358207

Pacifici, G M; Gucci, A; Giuliani, L

96

Non-steroidal anti-inflammatory drugs interact with testosterone glucuronidation  

Microsoft Academic Search

Testosterone and epitestosterone are secreted mainly as glucuronide metabolites and the urinary ratio of testosterone glucuronide to epitestosterone glucuronide, often called T\\/E, serves as a marker for possible anabolic steroids abuse by athletes. UDP-glucuronosyltransferase (UGT) 2B17 is the most important catalyst of testosterone glucuronidation. The T\\/E might be affected by drugs that interact with UGT2B17, or other enzymes that contribute

Taina Sten; Moshe Finel; Birgitta Ask; Anders Rane; Lena Ekström

2009-01-01

97

Regioselective and Stereospecific Glucuronidation of trans- and cis-Resveratrol in Human  

Microsoft Academic Search

Resveratrol (3,5,4?-trihydroxy-trans-stilbene) is a polyphenol present in wine, which has been reported to have anti-inflammatory, anti-platelet, and anti-carcinogenic effects. The glucuronidation of this compound and that of the cis-isomer also naturally present, has been investigated in human liver microsomes. Both isomers were actively glucuronidated. The reaction led to the formation of two glucuronides (3-O- and 4?-O-glucuronides), whose structure was characterized

Virginie Aumont; Stéphanie Krisa; Eric Battaglia; Patrick Netter; Tristan Richard; Jean-Michel Mérillon; Jacques Magdalou; Nicole Sabolovic

2001-01-01

98

Glucuronidation of the mycotoxins alternariol and alternariol-9-methyl ether in vitro: chemical structures of glucuronides and activities of human UDP-glucuronosyltransferase isoforms.  

PubMed

Alternariol (AOH) and alternariol-9-methyl ether (AME) are major toxins produced by fungi of the genus Alternaria and are frequently found in various food items. Because AOH has three hydroxyl groups and AME two, the formation of various glucuronides must be expected. When AOH was incubated with hepatic and intestinal microsomes from rats, pigs and humans in the presence of uridine diphosphate glucuronic acid, two glucuronides were detected and tentatively identified as AOH-3-O-glucuronide and AOH-9-O-glucuronide. Under the same conditions, AME yielded predominantly AME-3-O-glucuronide and only small amounts of AME-7-O-glucuronide. The activities of all microsomes for the glucuronidation of AOH and AME were in the same range. Nine out of ten recombinant human UDP-glucuronosyltransferases (UGTs) were able to glucuronidate AOH, and eight out of ten UGTs had activity for AME. These data suggest that AOH and AME are readily glucuronidated in hepatic and extrahepatic tissues, implying that glucuronidation constitutes a major metabolic pathway in the disposition of these mycotoxins. PMID:23604930

Pfeiffer, E; Schmit, C; Burkhardt, B; Altemöller, M; Podlech, J; Metzler, M

2008-12-23

99

Validation of benzodiazepine ?-glucuronide primary reference materials for hydrolysis and quality assurance controls  

Microsoft Academic Search

The major metabolite of hydroxylated benzodiazepines is the ?-glucuronide metabolite, thus a hydrolysis step is included in benzodiazepine analyses in urine. We evaluated the new Alltech (R,S) oxazepam and lorazepam ?-glucuronide primary reference materials as hydrolysis controls and for use in proficiency testing. Using HPLC analysis and GC\\/MS analysis following acid and ?-glucuronidase hydrolysis, we found that the lorazepam ?-glucuronide

Carol L. O'Neal; Alphonse Poklis

1996-01-01

100

Effect of butylated hydroxyanisole on hepatic glucuronidation and biliary excretion of drugs in mice.  

PubMed

Inhibition of glucuronidation by depletion of UDP-glucuronic acid from liver impairs the hepatobiliary transport of glucuronidated xenobiotics. However, it is not known if enhancement of hepatic glucuronidation increases the biliary excretion of these compounds. Therefore, the effect of treatment with butylated hydroxyanisole (BHA), which increases hepatic glucuronidation capacity, on the biliary excretion of compounds undergoing glucuronidation was studied in mice. BHA-feeding (1% for 10 days) increased hepatic UDP-glucuronic acid content by 240% and enhanced hepatic UDP-glucuronosyltransferase activities (expressed per kg body weight) toward valproic acid, phenolphthalein, iopanoic acid and bilirubin 220, 180, 120 and 60%, respectively. BHA treatment did not influence the biliary excretion of unmetabolized cholephils, phenol-3,6-dibromphthalein disulphonate and phenolphthalein glucuronide, but enhanced that of phenolphthalein (+108%), iopanoic acid (+63%) and bilirubin (+33%) as glucuronides. However, these increases were apparent only in the initial phase of excretion. In contrast, BHA markedly decreased (-43%) the biliary excretion of valproic acid glucuronides. Simultaneously, BHA increased the urinary excretion of the glucuronides of phenolphthalein (+48%), iopanoic acid (+450%) and valproic acid (+150%). A shift in the distribution of iopanoic acid and valproic acid and metabolites from liver to kidney was also apparent in BHA-fed mice. Thus, enhanced glucuronidation does not facilitate the biliary excretion of all glucuronidated compounds and only transiently increases others. It is likely that this phenomenon is the result of the glucuronides readily entering the plasma and being excreted by the kidney. PMID:2900301

Gregus, Z; Klaassen, C D

1988-04-01

101

Use of alcohol and drugs by Norwegian employees: a pilot study using questionnaires and analysis of oral fluid  

Microsoft Academic Search

BACKGROUND: The use of alcohol and drugs may affect workplace safety and productivity. Little is known about the magnitude of this problem in Norway. METHODS: Employee recruitment methods with or without individual follow-up were compared. The employees filled in a questionnaire and provided a sample of oral fluid. Samples were analysed for alcohol, ethyl glucuronide (EtG; a biological marker of

Hallvard Gjerde; Asbjørg S Christophersen; Inger S Moan; Borghild Yttredal; J Michael Walsh; Per T Normann; Jørg Mørland

2010-01-01

102

Determination of morphine and its 3- and 6-glucuronides, codeine, codeine-glucuronide and 6-monoacetylmorphine in body fluids by liquid chromatography atmospheric pressure chemical ionization mass spectrometry  

Microsoft Academic Search

A selective assay of morphine-3-glucuronide (M3G), morphine-6-glucuronide (M6G), morphine, codeine, codeine-6-glucuronide (C6G) and 6-monoacetylmorphine (6-MAM) based on liquid chromatography atmospheric pressure chemical ionization mass spectrometry (LC–APCI–MS) is described. The drugs were extracted from serum, autopsy blood, urine, cerebrospinal fluid or vitreous humor using C18 solid-phase extraction cartridges and subjected to LC–APCI–MS analysis. The separation was performed on an ODS column

Maciej J Bogusz; Rolf-Dieter Maier; Manfred Erkens; Sarah Driessen

1997-01-01

103

A specific immunoassay for the determination of morphine and its glucuronides in human blood  

Microsoft Academic Search

The development of specific antisera for immunochemical determination of morphine, morphine-3-glucuronide and morphine-6-glucuronide\\u000a is described. Morphine was N-demethylated to normorphine and N-alkylated to give N-aminopropyl-normorphine as hapten for antisera\\u000a against morphine. As haptens for antisera against morphine-3-glucuronide and morphine-6-glucuronide, N-aminopropyl-nor-morphine\\u000a was glucuronidated in position 3 or 6 respectively. Each of these three haptens were coupled to BSA employing the glutaraldehyde

J. Beike; G. Blaschke; A. Mertz; H. Köhler; B. Brinkmann

1998-01-01

104

The homogeneity testing of EtG in hair reference materials: a high-throughput procedure using GC-NCI-MS.  

PubMed

The validation of a robust quantification procedure for EtG in hair using GC-NCI-MS is presented. Aqueous extraction is followed by complete lyophylization of the extract and derivatization with pentafluoropropionic anhydride (PFPA) under controlled temperature and duration. Clean-up of extracts was dispensable and standard single quadrupole MS displayed sufficient selectivity and sensitivity. The method displayed a wide linearity range and enabled LOD of 0.68 pg/mg, LOQ of 2.4 pg/mg, and precision below 8.12%. Since EtG was seen to display prolonged stability in the aqueous extracts and after derivatization with PFPA this straightforward procedure allows a routine throughput of large quantities of samples with little proneness to procedural scatter of results. The method was applied to demonstrate the homogeneity of two hair reference materials with mean EtG contents of 8.48 pg/mg and 22.0 pg/mg. Aside from the application in homogeneity studies of hair reference materials predominantly in the concentration range of 10-50 pg/mg the method was also designed for daily routine quantification of real-world sample with regard to drinking behavior assessment. PMID:23415165

Mönch, Bettina; Becker, Roland; Jung, Christian; Nehls, Irene

2013-02-13

105

Resveratrol Is Absorbed in the Small Intestine as Resveratrol Glucuronide  

Microsoft Academic Search

We have studied the absorption and metabolism of resveratrol in the jejunum in an isolated rat small intestine model. Only small amounts of resveratrol were absorbed across the enterocytes of the jejunum and ileum unmetabolised. The major compound detected on the serosal side was the glucuronide conjugate of resveratrol (96.5% ± 4.6 of the amount absorbed) indicating the susceptibility of

Gunter Kuhnle; Jeremy P. E. Spencer; George Chowrimootoo; Hagen Schroeter; Edward S. Debnam; S. Kaila S. Srai; Catherine Rice-Evans; Ulrich Hahn

2000-01-01

106

Stereoselective glucuronidation of carvedilol by Chinese liver microsomes*  

PubMed Central

Objective: To study the stereoselective glucuronidation of carvedilol (CARV) by three Chinese liver microsomes. Methods: The metabolites of CARV were identified by a hydrolysis reaction with ?-glucuronidase and HPLC-MS/MS. The enzyme kinetics for CARV enantiomers glucuronidation was determined by a reversed phase-high pressure liquid chromatography (RP-HPLC) assay using (S)-propafenone as internal standard after precolumn derivatization with 2,3,4,6-tetra-O-acetyl-?-D-glucopyranosylisothiocyanate. Results: Two CARV glucuronides were found in three Chinese liver microsomes incubated with CARV. The non-linear regression analysis showed that the values of K m and V max for (S)-CARV and (R)-CARV enantiomers were (118±44) µmol/L, (2 500±833) pmol/(min·mg protein) and (24±7) µmol/L, (953±399) pmol/(min·mg protein), respectively. Conclusion: These results suggested that there was a significant (P<0.05) stereoselective glucuronidation of CARV enantiomers in three Chinese liver microsomes, which might partly explain the enantioselective pharmacokinetics of CARV.

You, Lin-ya; Yu, Chun-na; Xie, Sheng-gu; Chen, Shu-qing; Zeng, Su

2007-01-01

107

Enzymatic synthesis of glucuronides using lipophilic hollow fiber membranes  

Microsoft Academic Search

A lipophilic hollow fiber membrane preparation was used for the enzymatic glucuronidation of lipophilic aromatic compounds. A crude solubilized microsomal enzyme preparation was circulated on the external side of the lipophilic membrane while the phenol containing buffer solution was circulated through the internal side of the hollow fiber membrane. Phenols, which accumulate in and penetrate the lipophilic membrane, were converted

F. Tegtmeier; K. Belsner; G. Brunner

1988-01-01

108

Routine determination of morphine, morphine 3-?- d-glucuronide and morphine 6-?- d-glucuronide in human serum by liquid chromatography coupled to electrospray mass spectrometry  

Microsoft Academic Search

A robust liquid chromatographic mass spectrometric method capable of quantifying morphine, morphine 3-?-d-glucuronide and morphine 6-?-d-glucuronide down to 1.0 ng\\/ml, 5.0 ng\\/ml and 2.0 ng\\/ml respectively in human serum is presented. The method was validated over linear ranges of 1.0 to 20.0 ng\\/ml for morphine, 5.0 to 500.0 ng\\/ml for morphine 3-?-d-glucuronide and 2.0 to 100.0 ng\\/ml for morphine 6-?-d-glucuronide

M Blanchet; G Bru; M Guerret; M Bromet-Petit; N Bromet

1999-01-01

109

21 CFR 584.200 - Ethyl alcohol containing ethyl acetate.  

Code of Federal Regulations, 2010 CFR

The feed additive ethyl alcohol containing ethyl acetate meets the requirement of 27 CFR 21.62, being not less than 92.5 percent ethyl alcohol, each 100 gallons having had added the equivalent of 4.25 gallons of 100 percent ethyl...

2009-04-01

110

Transport of 7Ethyl10-hydroxycamptothecin (SN38) by Breast Cancer Resistance Protein ABCG2 in Human Lung Cancer Cells  

Microsoft Academic Search

Overexpression of breast cancer resistance protein (BCRP) ABCG2 reportedly confers cancer cell resistance to camptothecin-based anticancer drugs, such as topotecan and 7-ethyl-10-hydroxycamptothecin (SN-38: the active metabolite of irinotecan). We have recently shown that SN-38-selected PC-6\\/SN2-5H human lung carcinoma cells overexpressed BCRP with the reduced intracellular accumulation of SN-38 and SN-38-glucuronide (S. Kawabata et al., Biochem. Biophys. Res. Commun. 280, 1216–1223,

Katsumi Nakatomi; Megumi Yoshikawa; Mikio Oka; Yoji Ikegami; Shinya Hayasaka; Kazumi Sano; Ken Shiozawa; Shigeru Kawabata; Hiroshi Soda; Toshihisa Ishikawa; Shinzo Tanabe; Shigeru Kohno

2001-01-01

111

Analysis of bile acid glucuronides in urine: group separation on a lipophilic anion exchanger.  

PubMed

A chromatographic separation of glucuronidated bile acids using the anion exchanger diethylaminohydroxypropyl Sephadex LH-20 (DEAP LH-20) is described. Group separation of non-sulfated, non-glucuronidated bile acids, bile acid glucuronides, bile acid monosulfates, and bile acid disulfates was obtained. The method allowed analysis of all these bile acid derivatives in the urine of 15 patients with cirrhosis of the liver and cholestasis. The patients excreted in mean 30.4 mumol/24 h non-sulfated, non-glucuronidated bile acids, 90.3 mumol bile acid monosulfates, and 10.2 mumol bile acid glucuronides. Glycine- or taurine-conjugated were 68% of the non-sulfated, non-glucuronidated bile acids, 96% of bile acid sulfates, and 81% of bile acid glucuronides. PMID:7116646

Stiehl, A; Raedsch, R; Rudolph, G; Czygan, P; Walker, S

1982-08-18

112

Regioselective glucuronidation of denopamine: marked species differences and identification of human udp-glucuronosyltransferase isoform.  

PubMed

Denopamine is one of the oral beta(1)-adrenoceptor-selective partial agonists. Denopamine glucuronide is the most abundant metabolite in human, rat, and dog urine when administered orally. Species differences in denopamine glucuronidation were investigated with liver microsomes obtained from humans and experimental animals. In rat and rabbit, only the phenolic glucuronide was detected, whereas in dog and monkey, not only the phenolic glucuronide but also the alcoholic glucuronide was found. In contrast, in humans, the alcoholic glucuronide was detected exclusively. The kinetics of denopamine glucuronidation in human liver microsomes showed a typical Michaelis-Menten plot. The K(m) and V(max) values accounted for 2.87 +/- 0.17 mM and 7.29 +/- 0.23 nmol/min/mg protein, respectively. With the assessment of denopamine glucuronide formation across a panel of recombinant UDP-glucuronosyltransferase (UGT) isoforms (UGT1A1, UGT1A3, UGT1A4, UGT1A6, UGT1A7, UGT1A8, UGT1A9, UGT1A10, UGT2B4, UGT2B7, UGT2B15, and UGT2B17), only UGT2B7 exhibited high denopamine glucuronosyltransferase activity. The K(m) value of denopamine glucuronidation in recombinant UGT2B7 microsomes was close to those in human liver and jejunum microsomes. The formation of denopamine glucuronidation by human liver, jejunum, and recombinant UGT2B7 microsomes was effectively inhibited by diclofenac, a known substrate for UGT2B7. The denopamine glucuronidation activities in seven human liver microsomes were significantly correlated with diclofenac glucuronidation activities (r(2) = 0.685, p < 0.05). These results demonstrate that the denopamine glucuronidation in human liver and intestine is mainly catalyzed by UGT2B7 and that glucuronidation of the alcoholic hydroxyl group, but not the phenolic hydroxyl group, occurs regioselectively in humans. PMID:15608137

Kaji, Hidefumi; Kume, Toshiyuki

2004-12-17

113

Determination of Kow Values for a Series of Aryl Glucuronides  

Microsoft Academic Search

Polynuclear aromatic hydrocarbons (PAHs) are a class of hazardous contaminants in the aquatic environment that readily accumulate in animals. We have recently become interested in understanding the formation, distribution, and elimination of phase II metabolites of PAHs in fish (McKim et al. 1993) in support of the U.S. EPA’s hazardous chemical risk assessment programs. Glucuronides are one of the important

D. W. Kuehl; J. Christensen

1999-01-01

114

Studies on the disturbance of glucuronide formation in infectious hepatitis  

Microsoft Academic Search

The ability of the liver to form glucuronides was measured in 10 patients with infectious hepatitis. One test was done at the onset and another about four weeks later after the clinical symptoms had disappeared. N-acetyl-p-aminophenol (N.A.P.A.) or acetanilide was administered in doses ranging from 10 to 20 mg. per kg. body weight, either orally or by intravenous injection. N.A.P.A.

M. F. Vest; E. Fritz

1961-01-01

115

Variation in glucuronidation of lamotrigine in human liver microsomes.  

PubMed

Lamotrigine (LTG), a diaminotriazine anti-epileptic, is principally metabolized at the 2-position of the triazine ring to form a quaternary ammonium glucuronide (LTGG) by uridine glucuronosyl transferease (UGT) 1A3 and UGT1A4. It has been hypothesized that glucuronidation of anti-epileptic drugs is spared with age, despite a known decrease in liver mass, based on older studies with benzodiazepines such as lorazepam. To examine this, the formation rates of LTGG formation were measured by liquid chromatography-mass spectrometry (LC-MS) in a bank of human liver microsomes (HLMs) obtained from younger and elderly donors at therapeutic concentrations. The formation rate of LTGG was not significantly different in HLMs obtained from younger and elderly subjects. A four- to five-fold variation for the formation of LTGG was observed within each microsomal bank obtained from elderly and younger donors, and the range of LTGG formation was observed to be 0.15-0.78 nmoles min(-1) mg(-1) of protein across the entire set of HLMs (n = 36, elderly and younger HLMs). UGT1A4 and UGT1A3 catalysed the formation of LTGG with an intrinsic clearances of 0.28 and 0.02 microl min(-1) mg(-1) protein, respectively. UGT2B7 and UGT2B4 showed no measurable activity. No correlation was observed across the HLM bank for glucuronidation of LTG and valproic acid (a substrate for multiple UGT isoforms including UGT1A4). PMID:19387891

Argikar, U A; Remmel, R P

2009-05-01

116

Synthesis and iodine-125 labelling of glucuronide compounds for combined chemo- and radiotherapy of cancer  

Microsoft Academic Search

Some types of cancer cells have high levels of beta-glucoronidase activity. This enzyme is able to deglucuronidate a variety of glucuronide derivatives on the cell membrane. Either O- or N-glucuronides can be selectively incorporated into the cancer cells. If the aglycone is cytotoxic, the glucuronide can potentially be used as a selective anti-cancer drug in cancers with high levels of

Turan Ünak; Perihan Ünak; Binnur Ongun; Yusuf Duman

1997-01-01

117

Ethyl alcohol production  

SciTech Connect

Recent price increases and temporary shortages of petroleum products have caused farmers to search for alternate sources of fuel. The production of ethyl alcohol from grain is described and the processes involved include saccharification, fermentation and distillation. The resulting stillage has potential as a livestock feed.

Hofman, V.; Hauck, D.

1980-11-01

118

Enzyme-assisted synthesis and structural characterization of the 3-, 8-, and 15-glucuronides of deoxynivalenol.  

PubMed

4-Deoxynivalenol is one of the most prevalent mycotoxins in grain-based food and feed products worldwide. Conjugation of deoxynivalenol to glucuronic acid and elimination via the urine appears to be the major metabolism pathway, although with differing efficiency in different species. In order to make pure deoxynivalenol glucuronides for analytical methodologies available we intended to enzymatically synthesize glucuronides of deoxynivalenol using rat and human liver microsomes supplemented with uridine 5'-diphosphoglucuronic acid and alamethicin as detergent. Three glucuronides were isolated and purified using solid-phase extraction of microsomal incubations and subsequent semipreparative hydrophilic interaction chromatography. NMR spectra were obtained for all three compounds from solutions in methanol, showing that deoxynivalenol 3-O-?-D-glucuronide and deoxynivalenol 15-O-?-D-glucuronide were the major products from incubations of deoxynivalenol with rat and human liver microsomes, respectively. The NMR spectra of a third glucuronide showed replacement of the C-8 carbonyl by a ketal carbon. This glucuronide was finally identified as deoxynivalenol 8-O-?-D-glucuronide. The present study provides unequivocal structural evidence for three glucuronides of deoxynivalenol formed by liver enzymes. PMID:23374009

Uhlig, Silvio; Ivanova, Lada; Fæste, Christiane Kruse

2013-02-18

119

Simultaneous quantification of buprenorphine, norbuprenorphine, buprenorphine glucuronide, and norbuprenorphine glucuronide in human placenta by liquid chromatography mass spectrometry  

PubMed Central

A LCMS method was developed and validated for the determination of buprenorphine (BUP), norbuprenorphine (NBUP), buprenorphine glucuronide (BUP-Gluc), and norbuprenorphine glucuronide (NBUP-Gluc) in placenta. Quantification was achieved by selected ion monitoring of m/z 468.4 (BUP), 414.3 (NBUP), 644.4 (BUP-Gluc), and 590 (NBUP-Gluc). BUP and NBUP were identified monitoring MS2 fragments m/z 396, 414 and 426 for BUP, and 340, 364 and 382 for NBUP, and glucuronide conjugates monitoring MS3 fragments m/z 396 and 414 for BUP-Gluc, and 340 and 382 for NBUP-Gluc. Linearity was 1–50 ng/g. Intra-day, inter-day and total assay imprecision (% RSD) were <13.4%, and analytical recoveries were 96.2–113.1%. Extraction efficiencies ranged from 40.7–68%, process efficiencies 38.8–70.5%, and matrix effect 1.3–15.4%. Limits of detection were 0.8 ng/g for all compounds. An authentic placenta from an opioid-dependent pregnant woman receiving BUP pharmacotherapy was analyzed. BUP was not detected but metabolite concentrations were NBUP-Gluc 46.6, NBUP 15.7 and BUP-Gluc 3.2 ng/g.

Concheiro-Guisan, Marta; Shakleya, Diaa M.; Huestis, Marilyn A.

2011-01-01

120

GRAS Notice 000470: Ethyl cellulose  

Center for Food Safety and Applied Nutrition (CFSAN)

Text Version... Figure 1. Chemical Structure of Ethyl Cellulose ... Given the strong hydrophobic character of ethyl cellulose together with its high molecular mass ... More results from www.fda.gov/downloads/food/ingredientspackaginglabeling

121

Keap1 Recruits Neh2 through Binding to ETGE and DLG Motifs: Characterization of the Two-Site Molecular Recognition Model  

PubMed Central

The expression of the phase 2 detoxification enzymes and antioxidant proteins is induced at the transcriptional level by Nrf2 and negatively regulated at the posttranslational level by Keap1 through protein-protein interactions with and subsequent proteolysis of Nrf2. We found that the Neh2 domain of Nrf2 is an intrinsically disordered but biologically active regulatory domain containing a 33-residue central ?-helix followed by a mini antiparallel ?-sheet. Isothermal calorimetry analysis indicated that one Neh2 molecule interacts with two molecules of Keap1 via two binding sites, the stronger binding ETGE motif and the weaker binding DLG motif. Nuclear magnetic resonance titration study showed that these two motifs of the Neh2 domain bind to an overlapping site on the bottom surface of the ?-propeller structure of Keap1. In contrast, the central ?-helix of the Neh2 domain does not have any observable affinity to Keap1, suggesting that this region may serve as a bridge connecting the two motifs for the association with the two ?-propeller structures of a dimer of Keap1. Based on these observations, we propose that Keap1 recruits Nrf2 by the ETGE motif and that the DLG motif of the Neh2 domain locks its lysine-rich central ?-helix in a correct position to benefit ubiquitin signaling.

Tong, Kit I.; Katoh, Yasutake; Kusunoki, Hideki; Itoh, Ken; Tanaka, Toshiyuki; Yamamoto, Masayuki

2006-01-01

122

Organochlorines inhibit acetaminophen glucuronidation by redirecting UDP-glucuronic acid towards the D-glucuronate pathway  

SciTech Connect

Industry-derived organochlorines are persistent environmental pollutants that are a continuing health concern. The effects of these compounds on drug metabolism are not well understood. In the current study we present evidence that the inhibition of acetaminophen (APAP) glucuronidation by minute concentrations of organochlorines correlates well with their ability to stimulate the D-glucuronate pathway leading to ascorbate synthesis. A set of 6 arylated organochlorines, including 5 PCB (polychlorinated biphenyl) congeners, were assessed for their effects on APAP glucuronidation in isolated hepatocytes from male Sprague-Dawley rats. The capacity of each organochlorine to inhibit APAP glucuronidation was found to be directly proportional to its capacity to stimulate ascorbate synthesis. PCB153, PCB28 and bis-(4-chlorophenyl sulfone) (BCPS) in increasing order were the most effective organochlorines for inhibiting APAP glucuronidation and stimulating the D-glucuronate pathway. None of the 3 inhibitors of APAP glucuronidation were able to alter the expression of UGT1A6, UGT1A7 and UGT1A8 (the major isoforms responsible for APAP glucuronidation in the rat), however, their efficacy at inhibiting APAP glucuronidation was proportional to their capacity to deplete UDP-glucuronic acid (UDPGA). BCPS-mediated inhibition of APAP glucuronidation in isolated hepatocytes had non-competitive characteristics and was insensitive to the inactivation of cytochrome P450. The effective organochlorines were also able to selectively stimulate the hydrolysis of UDPGA to UDP and glucuronate in isolated microsomes, but could not inhibit APAP glucuronidation in microsomes when UDPGA was in excess. We conclude that organochlorines are able to inhibit APAP glucuronidation in hepatocytes by depleting UDPGA via redirecting UDPGA towards the D-glucuronate pathway. Because the inhibition is non-competitive, low concentrations of these compounds could have long term inhibitory effects on the glucuronidating capacity of hepatocytes.

Chan, Tom S. [Centre Hospitalier de l'Universite de Montreal, 264 Rene Levesque E, Montreal, Quebec, H2X 1P1 (Canada)], E-mail: chatsy@gmail.com; Wilson, John X. [Department of Exercise and Nutritional Sciences, University at Buffalo, Buffalo, New York, 14214 (United States); Selliah, Subajini; Bilodeau, Marc; Zwingmann, Claudia [Centre Hospitalier de l'Universite de Montreal, 264 Rene Levesque E, Montreal, Quebec, H2X 1P1 (Canada); Poon, Raymond [Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, K1A 0K9 (Canada); O'Brien, Peter J. [Faculty of Pharmacy, University of Toronto, Toronto, Ontario, M5S 3M2 (Canada)

2008-11-01

123

Species differences in the formation of vabicaserin carbamoyl glucuronide.  

PubMed

Vabicaserin is a potent 5-hydroxtryptamine 2C full agonist with therapeutic potential for a wide array of psychiatric disorders. Metabolite profiles indicated that vabicaserin was extensively metabolized via carbamoyl glucuronidation after oral administration in humans. In the present study, the differences in the extent of vabicaserin carbamoyl glucuronide (CG) formation in humans and in animals used for safety assessment were investigated. After oral dosing, the systemic exposure ratios of CG to vabicaserin were approximately 12 and up to 29 in monkeys and humans, respectively, and the ratios of CG to vabicaserin were approximately 1.5 and 1.7 in mice and dogs, respectively. These differences in systemic levels of CG are likely related to species differences in the rate and extent of CG formation and elimination. Whereas CG was the predominant circulating metabolite in humans and a major metabolite in mice, dogs, and monkeys, it was a relatively minor metabolite in rats, in which oxidative metabolism was the major metabolic pathway. Although the CG was not detected in plasma or urine of rats, approximately 5% of the dose was excreted in bile as CG in the 24-h collection postdose, indicating the rat had the metabolic capability of producing the CG. In vitro, in a CO(2)-enriched environment, the CG was the predominant metabolite in dog and human liver microsomes, a major metabolite in monkey and mice, and only a very minor metabolite in rats. Carbamoyl glucuronidation and hydroxylation had similar contributions to vabicaserin metabolism in mouse and monkey liver microsomes. However, only trace amounts of CG were formed in rat liver microsomes, and other metabolites were more prominent than the CG. In conclusion, significant differences in the extent of formation of the CG were observed among the various species examined. The exposure ratios of CG to vabicaserin were highest in humans, followed by monkeys, then mice and dogs, and lowest in rats, and the in vitro metabolite profiles generally correlated well with the in vivo metabolites. PMID:20032194

Tong, Zeen; Chandrasekaran, Appavu; DeMaio, William; Jordan, Ronald; Li, Hongshan; Moore, Robin; Poola, Nagaraju; Burghart, Peter; Hultin, Theresa; Scatina, JoAnn

2009-12-23

124

Rifampin induces alterations in mycophenolic acid glucuronidation and elimination: Implications for drug exposure in renal allograft recipients  

Microsoft Academic Search

Background: Exposure to mycophenolic acid (MPA) and its main metabolites (MPA 7-O-glucuronide [MPAG] and MPA acyl-glucuronide [AcMPAG]) is characterized by a large interindividual and intraindividual variability, resulting in part from variability in glucuronidation (via uridine diphosphate–glucuronosyltransferase isoforms) and excretion via multidrug resistance-associated protein 2 (MRP2). It can be hypothesized that drugs interfering with glucuronidation and excretion will alter (Ac)MPA(G) exposure.Methods:

Maarten Naesens; Dirk R. J. Kuypers; Frank Streit; Victor W. Armstrong; Michael Oellerich; Kristin Verbeke; Yves Vanrenterghem

2006-01-01

125

Determination of raloxifene and its glucuronides in human urine by liquid chromatography–tandem mass spectrometry assay  

Microsoft Academic Search

A selective, sensitive, accurate and precise liquid chromatography–tandem mass spectrometry (LC–MS\\/MS) method for determination of raloxifene and its three glucuronides: raloxifene-6-?-glucuronide (M1), raloxifene-4?-?-glucuronide (M2), raloxifene-6,4?-diglucuronide (M3) in urine samples is presented in this paper. To our knowledge the developed analytical method is the first fully validated method capable of simultaneous determination of raloxifene and its glucuronides in real urine samples.

Tina Trdan; Robert Roškar; Jurij Trontelj; Matjaž Ravnikar; Aleš Mrhar

2011-01-01

126

Determination of morphine, morphine-3-glucuronide and morphine-6-glucuronide in monkey and dog plasma by high-performance liquid chromatography–electrospray ionization tandem mass spectrometry  

Microsoft Academic Search

A specific and simultaneous assay of morphine, morphine-3-glucuronide (M-3-G) and morphine-6-glucuronide (M-6-G) in monkey and dog plasma has been developed. These methods are based on rapid isolation using solid phase extraction cartridge, and high-performance liquid chromatography (HPLC)–electrospray ionization (ESI)-tandem mass spectrometric (MSMS) detection. Analytes were separated on a semi-micro ODS column in acetonitrile–formic (or acetic) acid mixed solution. The selected

Masanari Mabuchi; Satomi Takatsuka; Masayuki Matsuoka; Kozo Tagawa

2004-01-01

127

EPA dashes ethyl`s hopes for MMT  

Microsoft Academic Search

Up until the Environmental Protection Agency (EPA; Washington) decided to deny Ethyl`s (Richmond, VA) petition to sell manganese-based gasoline additive MMT, many on Wall Street were bullish. Bets were that MMT sales could create an up to $200 million\\/year sales windfall for Ethyl with $60 million\\/year income, and push its near $26\\/share price up by at least 50 cts. But

Heller

1992-01-01

128

Acyl glucuronidation of fluoroquinolone antibiotics by the UDP-glucuronosyltransferase 1A subfamily in human liver microsomes.  

PubMed

Acyl glucuronidation is an important metabolic pathway for fluoroquinolone antibiotics. However, it is unclear which human UDP-glucuronosyltransferase (UGT) enzymes are involved in the glucuronidation of the fluoroquinolones. The in vitro formation of levofloxacin (LVFX), grepafloxacin (GPFX), moxifloxacin (MFLX), and sitafloxacin (STFX) glucuronides was investigated in human liver microsomes and cDNA-expressed recombinant human UGT enzymes. The apparent Km values for human liver microsomes ranged from 1.9 to 10.0 mM, and the intrinsic clearance values (calculated as Vmax/Km) had a rank order of MFLX > GPFX > STFX > > LVFX. In a bank of human liver microsomes (n = 14), the glucuronidation activities of LVFX, MFLX, and STFX correlated highly with UGT1A1-selective beta-estradiol 3-glucuronidation activity, whereas the glucuronidation activity of GPFX correlated highly with UGT1A9-selective propofol glucuronidation activity. Among 12 recombinant UGT enzymes, UGT1A1, 1A3, 1A7, and 1A9 catalyzed the glucuronidation of these fluoroquinolones. Results of enzyme kinetics studies using the recombinant UGT enzymes indicated that UGT1A1 most efficiently glucuronidates MFLX, and UGT1A9 most efficiently glucuronidates GPFX. In addition, the glucuronidation activities of MFLX and STFX in human liver microsomes were potently inhibited by bilirubin with IC50 values of 4.9 microM and 4.7 microM, respectively; in contrast, the glucuronidation activity of GPFX was inhibited by mefenamic acid with an IC50 value of 9.8 microM. These results demonstrate that UGT1A1, 1A3, and 1A9 enzymes are involved in the glucuronidation of LVFX, GPFX, MFLX, and STFX in human liver microsomes, and that MFLX and STFX are predominantly glucuronidated by UGT1A1, whereas GPFX is mainly glucuronidated by UGT1A9. PMID:15769885

Tachibana, Masaya; Tanaka, Makoto; Masubuchi, Yasuhiro; Horie, Toshiharu

2005-03-15

129

Enzymatic synthesis of uracil glucuronide, labeling with 125/131I, and in vitro evaluation on adenocarcinoma cells.  

PubMed

Human UDP-glucuronosyltransferases (UGTs) are a family of membrane-bound enzymes of the endoplasmic reticulum. They catalyze the glucuronidation of various endogenous and exogenous compounds, converting them into more polar glucuronides. In this study, uracil glucuronide was enzymatically synthesized using a UGT-rich microsome preparate, which was separated from Hutu-80 cells. Two different glucuronide derivatives were obtained, with a total reaction yield of 22.95% +/- 2.4% (n = 4). The glucuronide ligands were defined as uracil-n-glucuronide (UNG) and uracil-o-glucuronide (UOG). These were then analyzed by high-performance liquid chromatography-mass spectrometry and labeled with I-125 and I-131, separately. The radiolabeled (125/131)I-UNG and (125/131)I-UOG presented good incorporation ratios for Hutu-80, Caco-2, Detroit 562, and ACBRI 519 cells. The incorporation ratios of (125/131)I-UOG were higher than those of (125/131)I-UNG and of other labeled components for all cell types, and were also statistically significant compared to the values of (125/131)I-UNG for primary human intestinal epithelial cells (ACBRI 519) and human intestinal adenocarcinoma cells. Cell incorporation rates of n-glucuronides and o-glucuronides were higher compared to uracil, with o-glucuronides being more selective. The results suggest that both I-125- and I-131-labeled glucuronides can be used in imaging and therapy, and further research should be done in preclinical stages. PMID:20578839

Medine, Ilker Emin; Unak, Perihan; Sakarya, Serhan; Toksöz, Feriha

2010-06-01

130

Inhibition of morphine glucuronidation in the liver microsomes of rats and humans by monoterpenoid alcohols.  

PubMed

Morphine is an important drug used to alleviate moderate to severe pain. This opiate is mainly metabolized by glucuronidation to a non-analgesic metabolite, morphine-3-glucuronide (M-3-G) and an active metabolite morphine-6-glucuronide (M-6-G). To understand the modulation of morphine glucuronidation activity by environmental factors, the effect of endogenous and food-derived compounds on morphine uridine 5'-diphosphate (UDP)-glucuronosyltransferase (UGT) in rat and human microsomes was evaluated examining the 50% inhibitory concentration (IC(50)). The liver microsomes from Sprague-Dawley rats (RLM) and humans (HLM, 150 donors, pooled microsomes) were used as enzyme sources. Of 27 compounds tested, monoterpenoid alcohols, such as borneol and iso-borneol, exhibited a strong inhibitory effect on morphine glucuronidation in rat liver microsomes (RLM), whereas we failed to detect any inhibitory effect of endogenous substances including amino acids and sugars. The substances which have the ability to inhibit the activity in RLM are also inhibitory toward morphine glucuronidation in HLM and UGT2B7 baculosomes. However, the difference was that while the strongest inhibitory effect was observed for iso-menthol in HLM, borneol was the strongest inhibitor of the activity mediated by RLM. Although zidovudine is a typical substrate of UGT2B7, the inhibition of morphine glucuronidation by zidovudine was far weaker than that of monoterpenoid alcohols. These results demonstrate that dietary and supplementary monoterpenoid alcohols modify the pharmacokinetics and pharmacodynamics of morphine through inhibition of UGT2B7. PMID:22878261

Ishii, Yuji; Iida, Naoko; Miyauchi, Yuu; Mackenzie, Peter I; Yamada, Hideyuki

2012-08-08

131

Detection and identification of 2-nitro-morphine and 2-nitro-morphine-6-glucuronide in nitrite adulterated urine specimens containing morphine and its glucuronides.  

PubMed

In vitro urine adulteration is a well-documented practice adopted by individuals aiming to evade detection of drug use, when required to undergo mandatory sports and workplace drug testing. Potassium nitrite is an effective urine adulterant due to its oxidizing potential, and has been shown to mask the presence of many drugs of abuse. However, limited research has been conducted to understand its mechanism of action, and to explore the possibility of the drugs undergoing direct oxidation to form stable reaction products. In this study, opiates including morphine, codeine, morphine-3-glucuronide and morphine-6-glucuronide were exposed to potassium nitrite in water and urine to mimic the process of nitrite adulteration. It was found that two stable reaction products were detected by liquid chromatography-mass spectrometry (LC-MS) when morphine and morphine-6-glucuronide were exposed to nitrite. Isolation and elucidation using spectrometric and spectroscopic techniques revealed that they were 2-nitro-morphine and 2-nitro-morphine-6-glucuronide, respectively. These reaction products were also formed when an authentic morphine-positive urine specimen was fortified with nitrite. 2-Nitro-morphine was found to be stable enough to undergo the enzymatic hydrolysis procedure and also detectable by gas chromatography-mass spectrometry (GC-MS) after forming a trimethylsilyl derivative. On the contrary, morphine-3-glucuronide did not appear to be chemically manipulated when exposed to potassium nitrite in urine. These reaction products are not endogenously produced, are relatively stable and can be monitored with both LC-MS and GC-MS confirmatory techniques. As a result, these findings have revealed the possibility for the use of 2-nitro-morphine and 2-nitro-morphine-6-glucuronide as markers for the indirect monitoring of morphine and morphine-6-glucuronide in urine specimens adulterated with nitrite. Copyright © 2013 John Wiley & Sons, Ltd. PMID:23592389

Luong, Susan; Fu, Shanlin

2013-04-17

132

Dietary green and white teas suppress UDP-glucuronosyltransferase UGT2B17 mediated testosterone glucuronidation.  

PubMed

The anabolic steroid testosterone can be used by athletes to enhance athletic performance and muscle growth. UDP-glucuronosyltransferase (UGT2B17) is the key enzyme involved in the glucuronidation of testosterone to testosterone glucuronide, which also serves as a marker for the testosterone/epitestosterone (T/E) ratio used to detect testosterone abuse in sport. Inhibitors of testosterone glucuronidation could have an impact on circulating testosterone levels, thus aiding performance, as well as potentially affecting the urinary T/E ratio and therefore masking testosterone abuse. Previous reports have revealed that non-steroidal, anti-inflammatory drugs, diclofenac and ibuprofen, inhibit the UGT2B17 enzyme. The aim of this study is to analyse dietary tea samples for inhibition of testosterone glucuronidation and, where inhibition is present, to identify the active compounds. Analysis of testosterone glucuronidation was conducted by performing UGT2B17 assays with detection of un-glucuronidated testosterone using high performance liquid chromatography. The results from this study showed that testosterone glucuronidation was inhibited by the green and white tea extracts, along with specific catechin compounds, notably: epicatechin, epigallocatechin gallate (EGCG) and catechin gallate. The IC50 inhibition value for EGCG was determined, using a Dixon plot, to be 64 ?M, equalling the most active NSAID inhibitor diclofenac. Thus, common foodstuffs and their constituents, for the first time, have been identified as inhibitors of a key enzyme involved in testosterone glucuronidation. Whilst these common compounds are not substrates of the UGT2B17 enzyme, we showed that they inhibit testosterone glucuronidation which may have implications on current doping control in sport. PMID:22429924

Jenkinson, Carl; Petroczi, Andrea; Barker, James; Naughton, Declan P

2012-03-11

133

Ethyl fuel from nonpetroleum sources  

Microsoft Academic Search

It has been shown that ethanol-ester mixtures - Ethyl Fuel - can be prepared from nonpetroleum sources such as coal, oil shale, etc. Production consists of the following steps: gasification of basic feedstock, synthesis of methanol and carbonylation of methanol to Ethyl Fuel. Depending on the final composition, preparation from methanol can be carried out with 92 + % selectivity.

H. Beuther; T. P. Kobylinski; G. M. Singerman; W. R. Pretzer

1980-01-01

134

High-sensitivity analysis of buprenorphine, norbuprenorphine, buprenorphine glucuronide, and norbuprenorphine glucuronide in plasma and urine by liquid chromatography-mass spectrometry.  

PubMed

A new method using ultra-fast liquid chromatography and tandem mass spectrometry (UFLC-MS/MS) was developed for the simultaneous determination of buprenorphine and the metabolites norbuprenorphine, buprenorphine-3?-glucuronide, and norbuprenorphine-3?-glucuronide in plasma and urine. Sample handling, sample preparation and solid-phase extraction procedures were optimized for maximum analyte recovery. All four analytes of interest were quantified by positive ion electrospray ionization tandem mass spectrometry after solid-phase microextraction. The lower limits of quantification in plasma were 1pg/mL for buprenorphine and buprenorphine glucuronide, and 10pg/mL for norbuprenorphine and norbuprenorphine glucuronide. The lower limits of quantitation in urine were 10pg/mL for buprenorphine, norbuprenorphine and their glucuronides. Overall extraction recoveries ranged from 68-100% in both matrices. Interassay precision and accuracy was within 10% for all four analytes in plasma and within 15% in urine. The method was applicable to pharmacokinetic studies of low-dose buprenorphine. PMID:24095872

Regina, Karen J; Kharasch, Evan D

2013-09-08

135

49 CFR 173.322 - Ethyl chloride.  

Code of Federal Regulations, 2011 CFR

... 2011-10-01 2011-10-01 false Ethyl chloride. 173.322 Section 173.322 Transportation...Preparation and Packaging § 173.322 Ethyl chloride. Ethyl chloride must be packaged in any of the following...

2011-10-01

136

Anti-tumour activity and toxicity of the new prodrug9-aminocamptothecin glucuronide (9ACG) in mice  

PubMed Central

Cancer chemotherapy is limited by the modest therapeutic index of most antineoplastic drugs. Some glucuronide prodrugs may display selective anti-tumour activity against tumours that accumulate ?-glucuronidase. We examined the toxicity and anti-tumour activity of 9-aminocamptothecin glucuronide, a new glucuronide prodrug of 9-aminocamptothecin, to evaluate its potential clinical utility. 9-aminocamptothecin glucuronide was 25–60 times less toxic than 9-aminocamptothecin to five human cancer cell lines. ?-glucuronidase activated 9-aminocamptothecin glucuronide to produce similar cell killing as 9-aminocamptothecin or topotecan. The in vivo toxicity of 9-aminocamptothecin glucuronide in BALB/c mice was dose-, route-, sex- and age-dependent. 9-aminocamptothecin glucuronide was significantly less toxic to female than to male mice but the difference decreased with age. 9-aminocamptothecin glucuronide and 9-aminocamptothecin produced similar inhibition (?80%) of LS174T human colorectal carcinoma tumours. 9-aminocamptothecin glucuronide cured a high percentage of CL1-5 human lung cancer xenografts with efficacy that was similar to or greater than 9-aminocamptothecin, irinotecan and topotecan. The potent anti-tumour activity of 9-aminocamptothecin glucuronide suggests that this prodrug should be further evaluated for cancer treatment. British Journal of Cancer (2002) 86, 1634–1638. DOI: 10.1038/sj/bjc/6600317 www.bjcancer.com © 2002 Cancer Research UK

Prijovich, Z M; Chen, B-M; Leu, Y-L; Chern, J-W; Roffler, S R

2002-01-01

137

A study of ethyl glucuronide in post-mortem blood as a marker of ante-mortem ingestion of alcohol  

Microsoft Academic Search

The possibility of post-mortem production of ethanol makes correct interpretation of ethanol detection in forensic autopsy samples difficult. Even though the levels of ethanol formed post-mortem are generally low, this may be highly relevant in cases where intake of alcohol was forbidden, for instance for pilots, professional drivers and countries with low legal alcohol limits for driving. Different criteria are

Gudrun Høiseth; Ritva Karinen; Asbjørg S. Christophersen; Linda Olsen; Per Trygve Normann; Jørg Mørland

2007-01-01

138

In Vitro Glucuronidation of the Antibacterial Triclocarban and Its Oxidative MetabolitesS?  

PubMed Central

Triclocarban (3,4,4?-trichlorocarbanilide; TCC) is widely used as an antibacterial in bar soaps. During use of these soaps, a significant portion of TCC is absorbed by humans. For the elimination from the body, glucuronidation plays a key role in both biliary and renal clearance. To investigate this metabolic pathway, we performed microsomal incubations of TCC and its hydroxylated metabolites 2?-OH-TCC, 3?-OH-TCC, and 6-OH-TCC. Using a new liquid chromatography-UV-mass spectrometry method, we could show a rapid glucuronidation for all OH-TCCs by the uridine-5?-diphosphate-glucuronosyltransferases (UGT) present in liver microsomes of humans (HLM), cynomolgus monkeys (CLM), rats (RLM), and mice (MLM). Among the tested human UGT isoforms, UGT1A7, UGT1A8, and UGT1A9 showed the highest activity for the conjugation of hydroxylated TCC metabolites followed by UGT1A1, UGT1A3, and UGT1A10. Due to this broad pattern of active UGTs, OH-TCCs can be efficiently glucuronidated in various tissues, as shown for microsomes from human kidney (HKM) and intestine (HIM). The major renal metabolites in humans, TCC-N-glucuronide and TCC-N?-glucuronide, were formed at very low conversion rates (<1%) by microsomal incubations. Low amounts of N-glucuronides were generated by HLM, HIM, and HKM, as well as by MLM and CLM, but not by RLM, according to the observed species specificity of this metabolic pathway. Among the human UGT isoforms, only UGT1A9 had activity for the N-glucuronidation of TCC. These results present an anomaly where in vivo the predominant urinary metabolites of TCC are N and N?-glucuronides, but these compounds are slowly produced in vitro.

Schebb, N. H.; Franze, B.; Maul, R.; Ranganathan, A.

2012-01-01

139

UGT2B10 genotype influences nicotine glucuronidation, oxidation and consumption  

PubMed Central

Background Tobacco exposure is routinely assessed by quantifying nicotine metabolites in plasma or urine. On average, 80% of nicotine undergoes C-oxidation to cotinine. However, interindividual variation in nicotine glucuronidation is substantial and glucuronidation accounts for from 0 to 40% of total nicotine metabolism. We report here the effect of a polymorphism in a UDP-glucuronsyl transferase, UGT2B10, on nicotine metabolism and consumption. Methods Nicotine, cotinine, their N-glucuronide conjugates, and total trans-3'-hydroxycotinine were quantified in the urine (n=327) and plasma (n =115) of smokers. Urinary nicotine N-oxide was quantified in 105 smokers. Nicotine equivalents, the sum of nicotine and all major metabolites, were calculated for each smoker. The relationship of the UGT2B10 Asp67Tyr allele to nicotine equivalents, N-glucuronidation, and C-oxidation was determined. Results Individuals heterozygous for the Asp67Tyr allele excreted less nicotine or cotinine as their glucuronide conjugates than wild-type, resulting in a 60% lower ratio of cotinine glucuronide:cotinine, a 50% lower ratio of nicotine glucuronide:nicotine and increased cotinine and trans-3'-hydroxycotinine. Nicotine equivalents, a robust biomarker of nicotine intake, were lower among Asp67Tyr heterozygotes compared to individuals without this allele; 58.2 nmol/ml (95% CI, 48.9 – 68.2) versus 69.2 nmol/ml (95% CI, 64.3 – 74.5). Conclusions Individuals heterozygous for UGT2B10 Asp67Tyr consume less nicotine than do wild type smokers. This striking observation suggests that variations in nicotine N-glucuronidation, as reported for nicotine C-oxidation, may influence smoking behavior. Impact UGT2B10 genotype influences nicotine metabolism and should be taken into account when characterizing the role of nicotine metabolism on smoking.

Berg, Jeannette Zinggeler; von Weymarn, Linda; Thompson, Elizabeth A.; Wickham, Katherine M.; Weisensel, Natalie A.; Hatsukami, Dorothy K.; Murphy, Sharon E.

2010-01-01

140

Profiling of 19-norandrosterone sulfate and glucuronide in human urine: Implications in athlete's drug testing  

Microsoft Academic Search

19-Norandrosterone (19-NA) as its glucuronide derivative is the target metabolite in anti-doping testing to reveal an abuse of nandrolone or nandrolone prohormone. To provide further evidence of a doping with these steroids, the sulfoconjugate form of 19-norandrosterone in human urine might be monitored as well. In the present study, the profiling of sulfate and glucuronide derivatives of 19-norandrosterone together with

Emmanuel Strahm; Norbert Baume; Patrice Mangin; Martial Saugy; Christiane Ayotte; Christophe Saudan

2009-01-01

141

The ABC-like vacuolar transporter for rye mesophyll flavone glucuronides is not species-specific.  

PubMed

In many cases, the vacuolar uptake of secondary metabolites has been demonstrated to be strictly specific for a given compound and plant species. While most plants contain glycosylated secondary substances, few cases are known where flavonoids may also carry negative charges, e.g. as glucuronide conjugates. Vacuolar transport of glucosylated phenylpropanoid derivatives has been shown to occur by proton substrate antiport mechanisms (Klein, M., Weissenböck. G., Dufaud, A., Gaillard, C., Kreuz, K., Martinoia, E., 1996. Different energization mechanisms drive the vacuolar uptake of a flavonoid glucoside and a herbicide glucoside. J. Biol. Chem. 271, 29,666-29,671). In contrast, flavone glucuronides appearing specifically in rye mesophyll vacuoles are taken up by direct energisation utilising MgATP, strongly arguing for the presence of an ATP-binding cassette (ABC) transporter belonging to the subfamily of multidrug resistance-associated proteins (MRP) on the rye vacuolar membrane (Klein, M., Martinoia, E., Hoffmann-Thoma, G., Weissenböck, G., 2000. A membrane-potential dependent, ubiquitous ABC-like transporter mediates the vacuolar uptake of rye flavone glucuronides regulation of glucturonide uptake by glutathione and its conjugates. Plant Journal 21, 289-304). MRPs are known to transport negatively charged organic anions. Results presented here suggest that the vacuolar directly energised MRP-like glucuronate pump for plant-specific flavone glucuronides is ubiquitously present in diverse plant species since rye flavone glucuronides are taken up into vacuoles isolated from the barley mesophyll or from the broccoli stalk parenchyma representing two species which do not synthesise glucuronidated secondary compounds. According to the transport characteristics and inhibition profile observed we propose the existence of a high-capacity, uncoupler-insensitive vacuolar ABC transporter for flavone glucuronides and possibly other negatively charged organic compounds -- plant-born or xenobiotic -- irrespective of the plant's capability to endogenously produce glucuronidated compounds. PMID:11219807

Klein, M; Martinoia, E; Hoffmann-Thoma, G; Weissenböck, G

2001-01-01

142

cis- and trans-Resveratrol Are Glucuronidated in Rat Brain, Olfactory Mucosa and Cultured Astrocytes  

Microsoft Academic Search

Background\\/Aims: Glucuronidation of cis- and trans-resveratrol (3,5,4’-trihydroxy-trans-stilbene), which is a naturally occurring phytoalexin known to exert a number of beneficial health effects, was investigated in rat brain, cultured astrocytes and olfactory mucosa. Methods: The isomers were incubated with tissue homogenates, microsomes, or rat liver recombinant UDP-glucuronosyltransferases in the presence of UDP-glucuronic acid. The glucuronides were separated by HPLC and quantitated.

Nicole Sabolovic; Tony Heurtaux; Anne-Claude Humbert; Stéphanie Krisa; Jacques Magdalou

2007-01-01

143

Characterization of In Vitro Glucuronidation Clearance of a Range of Drugs in Human Kidney Microsomes: Comparison with Liver and Intestinal Glucuronidation and Impact of Albumin  

PubMed Central

Previous studies have shown the importance of the addition of albumin for characterization of hepatic glucuronidation in vitro; however, no reports exist on the effects of albumin on renal or intestinal microsomal glucuronidation assays. This study characterized glucuronidation clearance (CLint, UGT) in human kidney, liver, and intestinal microsomes in the presence and absence of bovine serum albumin (BSA) for seven drugs with differential UDP-glucuronosyltransferase (UGT) 1A9 and UGT2B7 specificity, namely, diclofenac, ezetimibe, gemfibrozil, mycophenolic acid, naloxone, propofol, and telmisartan. The impact of renal CLint, UGT on accuracy of in vitro-in vivo extrapolation (IVIVE) of glucuronidation clearance was investigated. Inclusion of 1% BSA for acidic drugs and 2% for bases/neutral drugs in incubations was found to be suitable for characterization of CLint, UGT in different tissues. Although BSA increased CLint, UGT in all tissues, the extent was tissue- and drug-dependent. Scaled CLint, UGT in the presence of BSA ranged from 2.22 to 207, 0.439 to 24.4, and 0.292 to 23.8 ml · min?1 · g tissue?1 in liver, kidney, and intestinal microsomes. Renal CLint, UGT (per gram of tissue) was up to 2-fold higher in comparison with that for liver for UGT1A9 substrates; in contrast, CLint, UGT for UGT2B7 substrates represented approximately one-third of hepatic estimates. Scaled renal CLint, UGT (in the presence of BSA) was up to 30-fold higher than intestinal glucuronidation for the drugs investigated. Use of in vitro data obtained in the presence of BSA and inclusion of renal clearance improved the IVIVE of glucuronidation clearance, with 50% of drugs predicted within 2-fold of observed values. Characterization and consideration of kidney CLint, UGT is particularly important for UGT1A9 substrates.

Gill, Katherine L.; Houston, J. Brian

2012-01-01

144

Evidence for P-glycoprotein-modulated penetration of morphine-6-glucuronide into brain capillary endothelium.  

PubMed Central

1. Morphine-6-glucuronide is one of the major metabolites of morphine. The potent analgesic action of this compound together with its potential lower apparent toxicity in man, when compared with morphine, indicated its clinical importance. 2. Primary cultures of porcine brain capillary endothelial cells were used to study brain penetration of morphine-6-glucuronide. Biochemical characterization of the cell cultures revealed a marked enrichment in enzymatic activity of alkaline phosphatase (56 fold) and angiotensin converting enzyme (230 fold) as compared to whole brain tissue. By immunostaining the presence of vimentin, factor VIII, the tight junction associated protein ZO-1, and P-glycoprotein was shown. Functional characterization revealed that the carrier system responsible for transport of neutral amino acids was intact. 3. Uptake and transport of morphine-6-glucuronide was marginal and in the range of the extracellular marker sucrose. However, uptake of morphine-6-glucuronide was enhanced significantly (P < 0.0001) in presence of the inhibitors of P-glycoprotein, verapamil or vincristine. The finding that morphine-6-glucuronide may serve as a substrate for P-glycoprotein was confirmed in multidrug-resistant P388 tumour cells. 4. We conclude that penetration of the blood-brain barrier by morphine-6-glucuronide may depend on the expression of the product of the multidrug-resistance (MDR) gene in brain capillary endothelial cells. Images Figure 1 Figure 2 Figure 4 Figure 5

Huwyler, J.; Drewe, J.; Klusemann, C.; Fricker, G.

1996-01-01

145

Position preference on glucuronidation of mono-hydroxylflavones in human intestine.  

PubMed

Extensive intestinal glucuronidation has been previously reported in both human and animals after oral administration of naturally occurred flavonoids. The present study aims to investigate the relationship between human intestinal glucuronidation activity and the position of hydroxyl substitution on flavonoids. Seven commercially available mono-hydroxyflavones (HF), namely 3-, 5-, 6-, 7-, 2'-, 3'- and 4'-mono-hydroxyflavones, were chosen as model compounds. Glucuronidation activity of the selected seven HFs was investigated by incubating each HF at various concentrations with human jejunum S9 at 37 degrees C for 10 min. The generated glucuronides were identified by HPLC/MS and quantified by HPLC/UV. Metabolic kinetics parameters including Km and Vmax of each HF were determined. The results demonstrated that the glucuronidation activity of 6- and 3'-mono-hydroxyflavones was much greater than that of 3-, 4'-, 7- and 2'-HF with 5-HF to be the lowest. The findings imply that nucleophilicity and stereo-conformation of OH substituents are crucial for the intestinal glucuronidation of flavonoids. PMID:16376382

Zhang, Li; Lin, Ge; Zuo, Zhong

2005-12-22

146

Nitrosation Reactions of Ethyl Centralite.  

National Technical Information Service (NTIS)

Preliminary experiments are described in which ethyl centralite, a stabilizer frequently used in double-base propellants, was reacted with nitrous acid in various concentrations. The chemical reactions taking place led to the formation of numerous derivat...

B. T. Newbold K. Taymaz R. MacDonald

1977-01-01

147

Molecular Structure of Ethyl maltol  

NSDL National Science Digital Library

Ethyl maltol was discovered in the 1970s. It was originally isolated from larch tree bark and is produced through fermentation-organic synthesis. Ethyl maltol occurs naturally in cereal, bread crust, coffee, and cocoa. This substance is also used as a flavor enhancer because it tends to mask bad tasting chemicals, and heightens richness and creaminess. The compound has been employed as a flavor enhancer in wine, chocolate, vanilla, fruit flavored drinks, pastries, candy, tobacco, cosmetics, and medicines.

2002-10-11

148

Familial resemblance for free androgens and androgen glucuronides in sedentary black and white individuals: the HERITAGE Family Study  

Microsoft Academic Search

Familial correlation analyses were used to evaluate the familial aggregation of plasma androgens and androgen glucuronides (testosterone (TESTO), dihydrotestos- terone (DHT), androstane-3,17-diol glucuronide (3-DIOL-G), and androsterone glucuronide (ADT-G)) in 505 members of 99 white families and 296 members of 111 black families participating in the Health, Risk Factors, Exercise Training and Genetics (HERITAGE) Family Study. Each of these four measures

Y Hong; J Gagnon; T Rice; L Pérusse; A S Leon; J S Skinner; J H Wilmore; D C Rao

2001-01-01

149

Radioiodination and preliminary biological tests of aniline-mustard and its glucuronide conjugate as a potential anticancer prodrug  

Microsoft Academic Search

Aniline-mustard and its glucuronide conjugate were radioiodinated with 131I. The preliminary dynamic tests were carried out on rabbits. The scintigrams showed clearly that the glucuronide conjugate of aniline-mustard was very quickly cleared from the metabolism, accumulating in the bladder in about 15 minutes. The clearance time of radioiodinated aniline-mustard-glucuronide was considerably longer (about 45 min.). The results obtained from the

T. Ünak; Z. Akgün; Y. Duman; Y. Yildirim; U. Avciba?i; B. Çetinkaya

2003-01-01

150

Effect of UDP-glucuronosyltransferase 1A8 polymorphism on raloxifene glucuronidation.  

PubMed

Raloxifene is an antiestrogen marketed for the treatment of osteoporosis. The major metabolic pathway of raloxifene is glucuronidation at 6- and/or 4'-positions, which is mainly catalyzed by UDP-glucuronosyltransferase 1A8 (UGT1A8) expressed in extrahepatic tissues such as the small intestine and colon. Two non-synonymous allelic variants, termed UGT1A8*2 (518C>G, A173G) and UGT1A8*3 (830G>A, C277Y), have been found in Caucasian, African-American and Asian populations. In this study, the effect of amino acid substitutions in UGT1A8 on raloxifene glucuronidation was studied using recombinant UGT1A8 enzymes of wild-type (UGT1A8.1) and variant UGT1A8 (UGT1A8.2 and UGT1A8.3) expressed in Sf9 cells. Raloxifene 6- and 4'-glucuronidation by UGT1A8.1 exhibited negative allosteric kinetics. The Km and Vmax values of UGT1A8.1 were 15.0 ?M and 111 pmol/min/mg protein for 6-glucuronidation, and 9.35 ?M and 232 pmol/min/mg protein for 4'-glucuronidation, respectively. The kinetics of raloxifene 6-glucuronidation by UGT1A8.2 was positive allosteric, whereas the kinetics of raloxifene 4'-glucuronidation was negative allosteric. The S50 value of raloxifene 6-glucuronidation was markedly low (1.2%) compared with the Km value of UGT1A8.1, and the Km value for raloxifene 4'-glucuronidation was 29% that of UGT1A8.1. The Vmax value for raloxifene 6-glucuronidation by UGT1A8.2 was comparable to that of UGT1A8.1, whereas the Vmax value for raloxifene 4'-glucuronidation was significantly lower (54%) than that of UGT1A8.1. The activities of raloxifene 6- and 4'-glucuronidation in UGT1A8.3 were markedly lower than those of UGT1A8.1. In mycophenolic acid glucuronidation, the kinetics by wild-type and variant UGT1A8s fitted the Michaelis-Menten model. The Km and Vmax values of UGT1A8.1 were 123 ?M and 4820 pmol/min/mg protein, respectively. The Km and Vmax values of UGT1A8.2 were comparable to those of UGT1A8.1. The Km value of UGT1A8.3 was similar to that of UGT1A8.1, whereas the Vmax value was reduced to 2.4% of UGT1A8.1. These findings suggest that A173G and C277Y substitutions of UGT1A8 change the metabolic ability toward raloxifene, and that the polymorphic alleles of UGT1A8 may influence the clinical response and bioavailability of medicines metabolized mainly by UGT1A8. PMID:23499758

Kokawa, Yuki; Kishi, Naoki; Jinno, Hideto; Tanaka-Kagawa, Toshiko; Narimatsu, Shizuo; Hanioka, Nobumitsu

2013-03-14

151

Glycerolysis of acyl glucuronides as an artifact of in vitro drug metabolism incubations.  

PubMed

During an investigation of the in vitro glucuronidation of benoxaprofen by human liver S-9 fraction, an unusual drug-related entity possessing a protonated molecular ion that was 74 mass units greater than the parent drug was observed. It was identified as the glycerol ester of benoxaprofen. Formation of this entity required inclusion of uridine diphosphoglucuronic acid (UDPGA) in the incubation, suggesting the formation of benoxaprofen acyl glucuronide followed by transesterification with the glycerol present in the incubation due to its presence as a stabilizer for liver subcellular fractions. Formation occurred during the sample work-up procedure while the samples were subjected to evaporation in vacuo, which does not remove glycerol. Conversion of purified benoxaprofen acyl glucuronide to the glycerol ester was demonstrated in glycerol at 37 degrees C. Other drugs that are converted to acyl glucuronides in vitro (diclofenac, mefenamic acid, tolmetin, and naproxen) were also shown to form corresponding glycerol esters when incubated with human liver S-9 fraction and UDPGA. The potential formation of glycerol esters of carboxylic acid drugs undergoing acyl glucuronidation in vitro represents an experimental artifact to which drug metabolism scientists should be aware. PMID:19439485

Obach, R Scott

2009-05-13

152

Identification of etoposide glucuronide as a major metabolite of etoposide in the rat and rabbit.  

PubMed

Isolated livers from male Sprague-Dawley rats were perfused at 20 ml/min for 3 h at 37 degrees C with 100 ml of an oxygenated, recirculating solution of 20% rat blood in Krebs bicarbonate buffer containing 20 micrograms/ml [3H]etoposide. Ninety % of administered radioactivity was eliminated in bile over a 3-h collection period. The clearance of etoposide was 3.56 ml/min indicating that, in the rat, it is not highly extracted. Its clearance is, therefore, independent of hepatic blood flow. Etoposide was both excreted into the bile and metabolized by the liver. Perfusate and bile samples analyzed by reverse-phase high-performance liquid chromatography techniques were found to contain three peaks of radioactivity. Positive and negative ion fast atom bombardment mass spectrometry identified the first two peaks as etoposide glucuronides and the third peak as parent drug. Following the i.v. administration of etoposide to rabbits, etoposide glucuronide was also identified in rabbit urine. The recovery of etoposide both from rabbit urine and rat bile was increased by preincubation with glucuronidase. However, the glucuronides were relatively resistant to the action of glucuronidase and showed varying sensitivity to the type of glucuronidase and the reaction conditions used. These studies document the presence of etoposide glucuronide as an etoposide metabolite in two mammalian species and suggest that previous clinical studies using beta-glucuronidase to quantitate glucuronide formation may have underestimated this metabolite due to its relative resistance to some glucuronidase preparations. PMID:3349461

Hande, K; Anthony, L; Hamilton, R; Bennett, R; Sweetman, B; Branch, R

1988-04-01

153

Ethyl diazoacetate synthesis in flow  

PubMed Central

Summary Ethyl diazoacetate is a versatile compound in organic chemistry and frequently used on lab scale. Its highly explosive nature, however, severely limits its use in industrial processes. The in-line coupling of microreactor synthesis and separation technology enables the synthesis of this compound in an inherently safe manner, thereby making it available on demand in sufficient quantities. Ethyl diazoacetate was prepared in a biphasic mixture comprising an aqueous solution of glycine ethyl ester, sodium nitrite and dichloromethane. Optimization of the reaction was focused on decreasing the residence time with the smallest amount of sodium nitrite possible. With these boundary conditions, a production yield of 20 g EDA day?1 was achieved using a microreactor with an internal volume of 100 ?L. Straightforward scale-up or scale-out of microreactor technology renders this method viable for industrial application.

Delville, Marielle M E; van Hest, Jan C M

2013-01-01

154

Reduction of TEM/ETG-scale Density Fluctuations in the Core and Edge of H-mode DIII-D Plasmas  

NASA Astrophysics Data System (ADS)

Improved confinement during H-mode has been linked to ExB shear suppression of large-scale (k??s<=0.3) turbulence within an edge transport barrier. While larger scale eddies are preferentially suppressed by increased shear flow in this paradigm, the effects on smaller scale (TEM/ETG-scale) turbulence are less certain. Recent results from DIII-D provide the first experimental evidence that intermediate-scale turbulence (1 < k??s<=3) together with larger-scale electron temperature fluctuations [1] are also reduced promptly at the L-H transition. These reductions are not confined to the edge region. Intermediate-scale density fluctuations obtained via Doppler backscattering, are significantly reduced (30%-50%) over a range of normalized radii (0.5 <=r/a <=0.85) within a few ms of the L-H transition. A larger reduction (>=75%) is observed at the top of the pedestal (r/a ˜0.9) within 0.2 ms. In addition, low-k electron temperature fluctuations (k??s<=0.3, from correlation ECE) are strongly reduced (>75%) at the L-H mode transition and during QH-mode (r/a ˜0.7). Gyrokinetic simulation results [2] predict that Te fluctuations contribute significantly to L-mode electron heat transport, hence, the observed reduction is likely an important factor in the observed improved H-mode electron heat confinement (?e^QH/?3^L < 0.25). Doppler backscattering is also utilized to probe time-dependent shear flows (i.e. zonal flows). The results clearly indicate that zonal flow levels are anti-correlated with the amplitude of intermediate-scale density turbulence in L-mode, suggesting that zonal flows play an important role in turbulence/transport regulation. 3pt [1] L. Schmitz et al., Phys. Rev. Lett. 100, 035002 (2008).[2] A.E. White et al., Phys. Plasmas 15, 056116 (2008).

Schmitz, L.

2008-11-01

155

Glucuronidation as a Mechanism of Intrinsic Drug Resistance in Human Colon Cancer: Reversal of Resistance by Food Additives  

Microsoft Academic Search

Colon cancer exhibits inherent insensitivity to chemotherapy by mech- anisms that are poorly characterized. We have shown that human colon cancer cells are efficient in drug conjugation catalyzed by UDP-glucu- ronosyltransferases (UGTs) and now report on the role of glucuronidation in de novo resistance to two topoisomerase I inhibitors. Identification of the UGT responsible for glucuronidation of SN-38 and the

Jeffrey Cummings; Brian T. Ethell; Lesley Jardine; Gary Boyd; Janet S. Macpherson; Brian Burchell; John F. Smyth; Duncan I. Jodrell

2003-01-01

156

Steroid and steroid glucuronide profiles in urine during pregnancy determined by liquid chromatography-electrospray ionization-tandem mass spectrometry.  

PubMed

An ultra performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-MS/MS) method was developed for the analysis of steroids and their glucuronides in urine samples. The method provides high sensitivity and fast analysis, as both steroids and their glucuronides can be analyzed directly without hydrolysis or complex sample preparation. The method was applied in profiling of targeted and nontargeted steroids and steroid glucuronides during pregnancy. The concentrations of 11 of 27 targeted steroids and steroid glucuronides and the concentrations of 25 nontargeted steroid glucuronides increased about 10-400 fold during the pregnancy. The concentrations of most of these 36 compounds began to increase in the first days of the pregnancy, increased gradually during the pregnancy, achieved a maximum in late pregnancy, and decreased sharply after delivery. Exceptionally, the concentrations of allopregnanolone and 17-hydroxypregnenolone started to increase later than those of the other steroids. Moreover, the concentrations of E2 glucuronides began to decrease one week before the delivery, in contrast to most of the steroids and steroid glucuronides, whose concentrations dropped sharply during the delivery. Concentrations of 34 compounds decreased noticeably when the subject was on sick leave owing a series of painful contractions. The results suggest that steroids and especially steroid glucuronides may provide a valuable diagnostic tool to follow the course of pregnancy. PMID:24176505

Jäntti, Sirkku E; Hartonen, Minna; Hilvo, Mika; Nygren, Heli; Hyötyläinen, Tuulia; Ketola, Raimo A; Kostiainen, Risto

2013-09-30

157

Species and Gender Differences Affect the Metabolism of Emodin via Glucuronidation  

PubMed Central

The aim of the present study was to define the mechanisms responsible for poor bioavailability of emodin by determining its metabolism using in vitro and in situ disposition models of the intestine and liver. Liver microsomes of mice, rats, guinea pigs, dogs, and humans were used along with the rat intestinal perfusion model and the rat intestinal microsomes. In the rat intestine, excretion rates of emodin-3-O-glucuronide were significantly different (p?glucuronidation in liver microsomes was species-dependent, and Km values varied 5.7-fold (3.2–18.2 ?M) in males and 2.8-fold (4.6–13.0 ?M) in females. The male intrinsic clearance (CLint) values differed by 5-fold (27.6–138.3 mL h?1?mg?1 protein), and female CLint values differed by 4.3-fold (24.3–103.5 mL h?1?mg?1 protein). Since CLint values of emodin glucuronidation were 10-fold higher than that of isoflavones, emodin was considered rapidly glucuronidated. In contrast to the large species-dependent effects on Km and CLint values, gender had a smaller effect on these kinetic parameters (2-fold, p?glucuronidation rates obtained using liver microsomes from various experimental animals of the same gender correlated well with those in human liver microsomes. In conclusion, Rapid metabolism by UDP-glucuronosyltransferase is the major reason why emodin has poor bioavailability. Species and gender affected emodin metabolism to a different degree, and experimental animals are expected to be useful in predicting emodin glucuronidation in humans.

Liu, Wei; Tang, Lan; Ye, Ling; Cai, Zheng; Xia, Bijun; Zhang, Jiajie

2010-01-01

158

In vitro characterization of glucuronidation of vanillin: identification of human UDP-glucuronosyltransferases and species differences.  

PubMed

Vanillin is a food flavoring agent widely utilized in foods, beverages, drugs, and perfumes and has been demonstrated to exhibit multiple pharmacological activities. Given the importance of glucuronidation in the metabolism of vanillin, the UDP-glucuronosyltransferase conjugation pathway of vanillin was investigated in this study. Vanillin glucuronide was identified by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and a hydrolysis reaction catalyzed by ?-glucuronidase. The kinetic study showed that vanillin glucuronidation by HLMs and HIMs followed Michaelis-Menten kinetics and the kinetic parameters were as follows: 134.9?±?13.5??M and 81.3?±?11.3??M for K(m) of HLMs and HIMs, 63.8?±?2.0?nmol/min/mg pro and 13.4 ±2.0?nmol/min/mg pro for Vmax of HLMs and HIMs. All UDP-glucuronosyltransferase (UGT) isoforms except UGT1A4, 1A9, and 2B7 showed the capability to glucuronidate vanillin, and UGT1A6 exerted the higher V(max)/K(m) values than other UGT isoforms for the glucuronidation of vanillin when assuming expression of isoforms is similar in recombinant UGTs. Kinetic analysis using liver microsomes from six studied speices indicated that vanillin had highest affinity for the monkey liver microsomes enzyme (K(m) ?=?25.6?±?3.2??M) and the lowest affinity for the mice liver microsomes enzyme (K(m) ?=?149.1?±?18.4??M), and intrinsic clearance was in the following order: monkey?>?dog?>?minipig?>?mice?>?rat?~?human. These data collectively provided important information for understanding glucuronidation of vanillin. PMID:23184728

Yu, Jian; Han, Jing-Chun; Hua, Li-Min; Gao, Ya-Jie

2012-11-26

159

Quantitative analysis of propofol-glucuronide in hair as a marker for propofol abuse.  

PubMed

The inappropriate or illegal use of propofol has recently come to the fore as a serious social issue in South Korea. Thus, in spite of its superior potency as a therapeutic drug, propofol was classified as a controlled drug under the purview of Narcotics Control Law in South Korea in February of 2011. Accordingly, the determination of propofol and/or its metabolites in biological specimens is required to prove ingestion. Therefore, to demonstrate chronic ingestion, a quantitative analytical method for propofol-glucuronide in hair was developed and validated using liquid chromatography-tandem mass spectrometry (LC-MS/MS). This method was applied to measure propofol-glucuronide in hair samples from 23 propofol abuse suspects and in both pigmented and nonpigmented hair from rats which had ingested propofol. Propofol-glucuronide in hair was extracted in methanol and then filtered and analyzed by LC-MS/MS with electrospray ionization in negative mode. The validation results of selectivity, matrix effect, recovery, linearity, precision and accuracy, and processed sample stability were satisfactory. The limit of detection was 20 pg/10 mg hair and the limit of quantification was 50 pg/10 mg hair. The concentration range of propofol-glucuronide in hair segments from 23 propofol abuse suspects was shown up to 1,410 pg/mg. The animal study demonstrated that the presence of melanin did not affect the deposition of propofol-glucuronide in hair. Thus, we propose propofol-glucuronide in hair as a marker for propofol abuse. This method will be very useful for monitoring the inappropriate use of propofol for both legal and public health aspects. PMID:23771527

Kim, Jihyun; In, Sanghwan; Park, Yuran; Park, Meejung; Kim, Eunmi; Lee, Sooyeun

2013-06-16

160

In vitro and in vivo oxidative metabolism and glucuronidation of anastrozole  

PubMed Central

AIMS Little information is available regarding the metabolic routes of anastrozole and the specific enzymes involved. We characterized anastrozole oxidative and conjugation metabolism in vitro and in vivo. METHODS A sensitive LC-MS/MS method was developed to measure anastrozole and its metabolites in vitro and in vivo. Anastrozole metabolism was characterized using human liver microsomes (HLMs), expressed cytochrome P450s (CYPs) and UDP-glucuronosyltransferases (UGTs). RESULTS Hydroxyanastrozole and anastrozole glucuronide were identified as the main oxidative and conjugated metabolites of anastrozole in vitro, respectively. Formation of hydroxyanastrozole from anastrozole was markedly inhibited by CYP3A selective chemical inhibitors (by >90%) and significantly correlated with CYP3A activity in a panel of HLMs (r = 0.96, P = 0.0005) and mainly catalyzed by expressed CYP3A4 and CYP3A5. The Km values obtained from HLMs were also close to those from CYP3A4 and CYP3A5. Formation of anastrozole glucuronide in a bank of HLMs was correlated strongly with imipramine N-glucuronide, a marker of UGT1A4 (r = 0.72, P < 0.0001), while expressed UGT1A4 catalyzed its formation at the highest rate. Hydroxyanastrozole (mainly as a glucuronide) and anastrozole were quantified in plasma of breast cancer patients taking anastrozole (1 mg day?1); anastrozole glucuronide was less apparent. CONCLUSION Anastrozole is oxidized to hydroxyanastrozole mainly by CYP3A4 (and to some extent by CYP3A5 and CYP2C8). Once formed, this metabolite undergoes glucuronidation. Variable activity of CYP3A4 (and probably UGT1A4), possibly due to genetic polymorphisms and drug interactions, may alter anastrozole disposition and its effects in vivo.

Kamdem, Landry K; Liu, Yong; Stearns, Vered; Kadlubar, Susan A; Ramirez, Jacqueline; Jeter, Stacie; Shahverdi, Karineh; Ward, Bryan A; Ogburn, Evan; Ratain, Mark J; Flockhart, David A; Desta, Zeruesenay

2010-01-01

161

Stereoselective urinary excretion of formoterol and its glucuronide conjugate in human  

PubMed Central

Aims Formoterol is an inhaled ?2-adrenoceptor agonist used as a racemic mixture of the active (R; R)- and inactive (S; S)-enantiomers (rac-formoterol). Glucuronidation is an important route of metabolism in humans which occurs faster for (S; S)-formoterol in human liver microsomes. The aim of this study was to investigate the stereoselectivity of urinary excretion of formoterol and its glucuronide conjugate after oral dosing with rac-formoterol. Methods Seven nonsmoking volunteers (six males, one female) were included in the study. After an overnight fast, a single 60 µg oral dose of rac-formoterol fumarate dihydrate was ingested. Urine samples were collected at 1 h intervals for the first 4 h, and at 6, 8, 12 and 24 h after dosing. Formoterol enantiomers were analysed by chiral h.p.l.c. assay and formoterol glucuronides were determined as formoterol enantiomers after enzymatic cleavage with ?-glucuronidase. Results The female subject displayed a different pattern of metabolism and statistical analysis was therefore limited to data for the six males. The median (range) of the total urinary excretion of formoterol was 37.8% (20.9–51.2%) of the dose. The medians (ranges) of the amounts of (R; R)- and (S; S)-formoterol and of (R; R)- and (S; S)-formoterol glucuronide excreted were 2.1 (1.0–2.9), 3.5 (2.6–3.8), 21.0 (13.1–31.0) and 10.3 (4.2–14.6)%, respectively, of the dose. Unchanged (S; S)-formoterol excretion was significantly greater than that of unchanged (R; R)-formoterol and (R; R)-formoterol glucuronide excretion was significantly greater than that of (S; S)-formoterol glucuronide. The total RR-formoterol (unchanged drug plus glucuronide) excreted was significantly greater than the total (S; S)-formoterol. Conclusions Our study demonstrates that the urinary excretion of formoterol in male humans after oral administration of rac-formoterol is stereoselective with preferential excretion of the active (R; R)-formoterol as unchanged drug and glucuronide. The different pattern of metabolism in the female subject provides impetus for further studies of the effect of gender on the stereoselective metabolism and pharmacokinetics of formoterol.

Zhang, Mei; Fawcett, J Paul; Shaw, John P

2002-01-01

162

Characterization of afloqualone N-glucuronidation: species differences and identification of human UDP-glucuronosyltransferase isoform(s).  

PubMed

Afloqualone (AFQ) is one of the centrally acting muscle relaxants. AFQ N-glucuronide is the most abundant metabolite in human urine when administered orally, whereas it was not detected in the urine when administered to rats, dogs, and monkeys. Species differences in AFQ N-glucuronidation were investigated with liver microsomes obtained from humans and experimental animals. The kinetics of AFQ N-glucuronidation in human liver microsomes showed a typical Michaelis-Menten plot. The K(m) and V(max) values accounted for 2019 +/- 85.9 muM and 871.2 +/- 17.9 pmol/min/mg protein, respectively. The V(max) and intrinsic clearance (CL(int)) values of AFQ N-glucuronidation in human liver were approximately 4- to 10-fold and 2- to 4-fold higher than those in rat, dog, and monkey, respectively. Among 12 recombinant human UDP-glucuronosyltransferase (UGT) isoforms, both UGT1A4 and UGT1A3 exhibited high AFQ N-glucuronosyltransferase activities. The K(m) value of AFQ N-glucuronidation in recombinant UGT1A4 microsomes was very close to that in human liver microsomes. The formation of AFQ N-glucuronidation by human liver, jejunum, and recombinant UGT1A4 microsomes was effectively inhibited by trifluoperazine, a known specific substrate for UGT1A4. The AFQ N-glucuronidation activities in seven human liver microsomes were significantly correlated with trifluoperazine N-glucuronidation activities (r(2) = 0.798, p < 0.01). In contrast, the K(m) value of AFQ N-glucuronidation in recombinant UGT1A3 microsomes was relatively close to that in human jejunum microsomes. These results demonstrate that AFQ N-glucuronidation in human is mainly catalyzed by UGT1A4 in the liver and by UGT1A3, as well as UGT1A4 in the intestine. PMID:15475412

Kaji, Hidefumi; Kume, Toshiyuki

2004-10-08

163

21 CFR 172.868 - Ethyl cellulose.  

Code of Federal Regulations, 2013 CFR

...Multipurpose Additives § 172.868 Ethyl cellulose. The food additive ethyl cellulose may be safely used in food in accordance...conditions: (a) The food additive is a cellulose ether containing ethoxy (OC2 H5 ) groups...

2013-04-01

164

21 CFR 172.868 - Ethyl cellulose.  

Code of Federal Regulations, 2010 CFR

...Multipurpose Additives § 172.868 Ethyl cellulose. The food additive ethyl cellulose may be safely used in food in accordance...conditions: (a) The food additive is a cellulose ether containing ethoxy (OC2 H5 ) groups...

2010-01-01

165

21 CFR 172.868 - Ethyl cellulose.  

Code of Federal Regulations, 2010 CFR

...Multipurpose Additives § 172.868 Ethyl cellulose. The food additive ethyl cellulose may be safely used in food in accordance...conditions: (a) The food additive is a cellulose ether containing ethoxy (OC2 H5 ) groups...

2009-04-01

166

21 CFR 573.420 - Ethyl cellulose.  

Code of Federal Regulations, 2010 CFR

...Food Additive Listing § 573.420 Ethyl cellulose. The food additive ethyl cellulose may be safely used in animal feed in accordance...conditions: (a) The food additive is a cellulose ether containing ethoxy (OC2 H5 ) groups...

2009-04-01

167

21 CFR 573.420 - Ethyl cellulose.  

Code of Federal Regulations, 2013 CFR

...Food Additive Listing § 573.420 Ethyl cellulose. The food additive ethyl cellulose may be safely used in animal feed in accordance...conditions: (a) The food additive is a cellulose ether containing ethoxy (OC2 H5 ) groups...

2013-04-01

168

Glucuronide and sulfate conjugates of ICI 182,780, a pure anti-estrogenic steroid. Order of addition, catalysis and substitution effects in glucuronidation  

Microsoft Academic Search

The 3-sulfate 4 and 3- and 17-glucuronide conjugates 5 and 6 of the pure anti-estrogenic steroid ICI 182,780 1, which is expected to be an effective agent for the treatment of breast cancer, have been prepared. The synthesis of 6 could only be satisfactorily achieved using an inverse addition technique, not previously employed in the glucuronic acid series: the value

John R Ferguson; John R Harding; Keith W Lumbard; Feodor Scheinmann; Andrew V Stachulski

2000-01-01

169

Aryl ethyl ethers prepared by ethylation using diethyl carbonate  

Microsoft Academic Search

An environmentally more convenient reaction for the production of industrially important aryl ethyl ethers (ArOEts) is described. ArOEts were selectively obtained in essentially quantitative yields by the reaction of corresponding (hetero)aromatic alcohols (ArOHs) with diethyl carbonate as the environmentally friendly alkylating reagent in the presence of N,N-dimethylacetamide used as polar aprotic cosolvent, and sodium ethoxide as the base. The reactions

T. Weidlich; M. Pokorný; Z. Pad?lková; A. R?ži?ka

2007-01-01

170

Expression of ?-glucuronidase on the surface of bacteria enhances activation of glucuronide prodrugs.  

PubMed

Extracellular activation of hydrophilic glucuronide prodrugs by ?-glucuronidase (?G) was examined to increase the therapeutic efficacy of bacteria-directed enzyme prodrug therapy (BDEPT). ?G was expressed on the surface of Escherichia coli by fusion to either the bacterial autotransporter protein Adhesin (membrane ?G (m?G)/AIDA) or the lipoprotein (lpp) outermembrane protein A (m?G/lpp). Both m?G/AIDA and m?G/lpp were expressed on the bacterial surface, but only m?G/AIDA displayed enzymatic activity. The rate of substrate hydrolysis by m?G/AIDA-BL21cells was 2.6-fold greater than by p?G-BL21 cells, which express periplasmic ?G. Human colon cancer HCT116 cells that were incubated with m?G/AIDA-BL21 bacteria were sensitive to a glucuronide prodrug (p-hydroxy aniline mustard ?-D-glucuronide, HAMG) with an half maximal inhibitory concentration (IC50) value of 226.53±45.4??M, similar to the IC50 value of the active drug (p-hydroxy aniline mustard, pHAM; 70.6±6.75??M), indicating that m?G/AIDA on BL21 bacteria could rapidly and efficiently convert HAMG to an active anticancer agent. These results suggest that surface display of functional ?G on bacteria can enhance the hydrolysis of glucuronide prodrugs and may increase the effectiveness of BDEPT. PMID:23598434

Cheng, C-M; Chen, F M; Lu, Y-L; Tzou, S-C; Wang, J-Y; Kao, C-H; Liao, K-W; Cheng, T-C; Chuang, C-H; Chen, B-M; Roffler, S; Cheng, T-L

2013-04-19

171

Efficient synthesis of glycyrrhetinic acid glycoside/glucuronide derivatives using silver zeolite as promoter.  

PubMed

3-O-Glycopyranosides of glycyrrhetinic acid have been synthesized in good to high yields and excellent stereoselectivity using glycosyl bromide donors and silver zeolite as promoter. In addition to the preparation of glycosides containing beta-linked glucosyl, 2-deoxy-2-trichloroacetamido-glucosyl, galactosyl, cellobiosyl and lactosyl residues, also the deactivated acetylated methyl glucopyranosyluronate bromide donor could be coupled to triterpene aglycon ester derivatives in good yields. The ester protecting group located at C-30 of the oleanolic acid scaffold exerted an influence on the overall yield, with the methylester-protected glycosyl acceptor giving better yields compared to the allyl, benzyl as well as diphenylmethyl ester aglycon. The acetyl-protected glucuronides were differently deblocked in high yields via Zemplén deacetylation or via hydrogenolysis followed by Zemplén deacetylation, and alkaline hydrolysis, respectively, to allow for a selective liberation of the ester groups from either the glucuronide or the glycyrrhetinic acid unit, respectively. The target glycosides/glucuronides serve as probes for pharmaceutical studies aimed at defining structure-activity relationships of glycoside/glucuronide triterpenes. PMID:19428000

del Ruiz Ruiz, Maria Carmen; Amer, Hassan; Stanetty, Christian; Beseda, Igor; Czollner, Laszlo; Shah, Priti; Jordis, Ulrich; Kueenburg, Bernhard; Classen-Houben, Dirk; Hofinger, Andreas; Kosma, Paul

2009-04-20

172

Profiling serum bile Acid glucuronides in humans: gender divergences, genetic determinants, and response to fenofibrate.  

PubMed

Glucuronidation, catalyzed by uridine 5'-diphospho-glucuronosyltransferase (UGT) enzymes, detoxifies cholestatic bile acids (BAs). We aimed to (i) characterize the circulating BA-glucuronide (BA-G) pool composition in humans, (ii) determine how sex and UGT polymorphisms influence this composition, and (iii) analyze the effects of the lipid-lowering drug fenofibrate on the circulating BA-G profile in 300 volunteers and 5 cholestatic patients. Eleven BA-Gs were determined in pre- and postfenofibrate samples. Men exhibited higher BA-G concentrations, and various genotype/BA-G associations were discovered in relevant UGT genes. The chenodeoxycholic acid-3G (CDCA-3G) concentration was associated with the UGT2B7 802C>T polymorphism. Glucuronidation assays confirmed the predominant role of UGT2B7 and UGT1A4 in CDCA-3G formation. Fenofibrate exposure increased the serum levels of five BA-G species, including CDCA-3G, and upregulated expression of UGT1A4, but not UGT2B7, in hepatic cells. This study demonstrated that fenofibrate stimulates BA glucuronidation in humans and thus reduces BA toxicity in the liver.Clinical Pharmacology & Therapeutics (2013); 94 4, 533-543. doi:10.1038/clpt.2013.122. PMID:23756370

Trottier, J; Perreault, M; Rudkowska, I; Levy, C; Dallaire-Theroux, A; Verreault, M; Caron, P; Staels, B; Vohl, M-C; Straka, R J; Barbier, O

2013-06-12

173

Evaluation of Indoxyl-Beta-D-Glucuronide as a Chromogen in Media Specific for 'Escherichia coli'.  

National Technical Information Service (NTIS)

Indoxyl-beta-D-glucuronide (indoxyl) was evaluated as a specific chromogen for detection of Escherichia coli by the membrane filter method. In all, 413 colonies were tested from the indoxyl-supplemented media, yielding 93.3% confirmation, as E. coli. Comp...

J. R. Haines T. C. Covert C. C. Rankin

1993-01-01

174

The ABC-like vacuolar transporter for rye mesophyll flavone glucuronides is not species-specific  

Microsoft Academic Search

In many cases, the vacuolar uptake of secondary metabolites has been demonstrated to be strictly specific for a given compound and plant species. While most plants contain glycosylated secondary substances, few cases are known where flavonoids may also carry negative charges, e.g. as glucuronide conjugates. Vacuolar transport of glucosylated phenylpropanoid derivatives has been shown to occur by proton–substrate antiport mechanisms

Markus Klein; Enrico Martinoia; Gudrun Hoffmann-Thoma; Gottfried Weissenböck

2001-01-01

175

The Human UGT1A3 Enzyme Conjugates Norursodeoxycholic Acid into a C23-ester Glucuronide in the Liver*  

PubMed Central

Norursodeoxycholic acid (norUDCA) exhibits efficient anti-cholestatic properties in an animal model of sclerosing cholangitis. norUDCA is eliminated as a C23-ester glucuronide (norUDCA-23G) in humans. The present study aimed at identifying the human UDP-glucuronosyltransferase (UGT) enzyme(s) involved in hepatic norUDCA glucuronidation and at evaluating the consequences of single nucleotide polymorphisms in the coding region of UGT genes on norUDCA-23G formation. The effects of norUDCA on the formation of the cholestatic lithocholic acid-glucuronide derivative and of rifampicin on hepatic norUDCA glucuronidation were also explored. In vitro glucuronidation assays were performed with microsomes from human tissues (liver and intestine) and HEK293 cells expressing human UGT enzymes and variant allozymes. UGT1A3 was identified as the major hepatic UGT enzyme catalyzing the formation of norUDCA-23G. Correlation studies using samples from a human liver bank (n = 16) indicated that the level of UGT1A3 protein is a strong determinant of in vitro norUDCA glucuronidation. Analyses of the norUDCA-conjugating activity by 11 UGT1A3 variant allozymes identified three phenotypes with high, low, and intermediate capacity. norUDCA is also identified as a competitive inhibitor for the hepatic formation of the pro-cholestatic lithocholic acid-glucuronide derivative, whereas norUDCA glucuronidation is weakly stimulated by rifampicin. This study identifies human UGT1A3 as the major enzyme for the hepatic norUDCA glucuronidation and supports that some coding polymorphisms affecting the conjugating activity of UGT1A3 in vitro may alter the pharmacokinetic properties of norUDCA in cholestasis treatment.

Trottier, Jocelyn; El Husseini, Diala; Perreault, Martin; Paquet, Sophie; Caron, Patrick; Bourassa, Sylvie; Verreault, Melanie; Inaba, Ted T.; Poirier, Guy G.; Belanger, Alain; Guillemette, Chantal; Trauner, Michael; Barbier, Olivier

2010-01-01

176

Interindividual and interethnic differences in the demethylation and glucuronidation of codeine.  

PubMed Central

1. The 8 h urinary excretion of codeine and seven of its metabolites was compared in 149 healthy Swedish Caucasians and 133 healthy Chinese following a single oral dose of 25 mg codeine phosphate. 2. The total 8 h urinary recovery of drug-related material was 74 +/- 24% in the Caucasians and 60 +/- 14% in the Chinese (P less than 0.001). The excretion of unchanged codeine was significantly higher in the Chinese (7.2%) compared with the Caucasians (4.3%, P less than 0.001). 3. The Caucasians excreted significantly greater proportions of codeine-6-glucuronide (C6G) (62%) than the Chinese (44%) (P less than 0.001). The frequency distribution of the log metabolic ratio (MR) for glucuronidation (codeine/C6G) was shifted towards higher values in the Chinese population. Males in both groups and Chinese smokers had significantly lower glucuronidation MRs than females and non-smokers in the respective populations (P less than 0.001). 4. The frequency distribution of the MR for O-demethylation (codeine/morphine (M) + M-3 and M-6-glucuronide (M3G and M6G) + normorphine (NM) was highly skewed in the Caucasians, suggestive of a bimodal distribution. There was a 160-fold interindividual variation in this MR. A unimodal distribution of the log O-demethylation MR was observed in Chinese. The Caucasians excreted less M and more M6G than did the Chinese (P less than 0.001). 5. Significantly more norcodeine (NC) and less NC-glucuronide (NCG) were excreted in the Chinese compared with the Caucasians (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Yue, Q Y; Svensson, J O; Alm, C; Sjoqvist, F; Sawe, J

1989-01-01

177

Identification of the rabbit liver UDP-glucuronosyltransferase catalyzing the glucuronidation of 4-ethoxyphenylurea (dulcin).  

PubMed

Dulcin (DL), 4-ethoxyphenylurea, a synthetic chemical about 200 times as sweet as sucrose, has been proposed for use as an artificial sweetener. DL is excreted as a urinary ureido-N-glucuronide after oral administration to rabbits. The phenylurea N-glucuronide is the only ureido conjugate with glucuronic acid known at present; therefore, DL is interesting as a probe to search for new functions of UDP-glucuronosyltransferases (UGTs). Seven UGT isoforms (UGT1A3, UGT1A4, UGT1A6, UGT1A7, UGT2B13, UGT2B14, and UGT2B16) have been identified from rabbit liver, but these UGTs have not been investigated using DL as a substrate. In this work, the identities of UGT isoforms catalyzing the formation of DL glucuronide were investigated using rabbit liver microsomes (RabLM) and cloned/expressed as rabbit UGT isoforms. DL-N-glucuronide (DNG) production was determined quantitatively in RabLM and homogenates of COS-7 cells expressing each UGT isoform by using electrospray liquid chromatography-tandem mass spectrometry. Analysis of DNG formation using RabLM, by Eadie-Hofstee plot, gave a Vmax of 0.911 nmol/min/mg protein and the Km of 1.66 mM. DNG formation was catalyzed only by cloned expressed rabbit UGT1A7 and UGT2B16 (Vmax of 3.98 and 1.16 pmol/min/mg protein and a Km of 1.23 and 1.69 mM, respectively). Substrate inhibition of UGT1A7 by octylgallate confirmed the significant contribution of UGT1A7 to the formation of DNG. Octylgallate was further shown to competitively inhibit DNG production by RabLM (Ki = 0.149 mM). These results demonstrate that UGT1A7 is the major isoform catalyzing the N-glucuronidation of DL in RabLM. PMID:15448114

Uesawa, Yoshihiro; Staines, Adam G; O'Sullivan, Audrey; Mohri, Kiminori; Burchell, Brian

2004-09-24

178

Analysis of catechol-type glucuronides in urine samples by liquid chromatography–electrospray ionization-tandem mass spectrometry  

Microsoft Academic Search

A direct and fast liquid chromatographic–electrospray ionization-tandem mass spectrometric (LC–ESI-MS–MS) method is described for the determination of 3-O-glucuronides of E- and Z-entacapone, nitecapone and tolcapone and 1-O- and 2-O-glucuronides of 4-nitrocatechol in urine. p-Nitrophenyl ?-d-glucuronide was used as internal standard. Spiked urine samples were prepared by solid-phase extraction and analysed by isocratic LC–ESI-MS–MS in negative ion mode. The ESI mass

Helena Keski-Hynnilä; Riitta Andersin; Leena Luukkanen; Jyrki Taskinen; Risto Kostiainen

1998-01-01

179

Vapor–liquid equilibrium of carbon dioxide with ethyl caproate, ethyl caprylate and ethyl caprate at elevated pressures  

Microsoft Academic Search

Vapor–liquid equilibrium (VLE) data were measured for CO2 with ethyl caproate, ethyl caprylate, and ethyl caprate using a semi-flow type apparatus at 308.2, 318.2 and 328.2 K over the pressure range from 1.6 to 9.2 MPa. In this paper, VLE data are reported. The VLE data were also correlated using the Soave–Redlich–Kwong and the Peng–Robinson equations of state with various

Weng-Hong Hwu; Jaw-Shin Cheng; Kong-Wei Cheng; Yan-Ping Chen

2004-01-01

180

An automatic 96-well solid phase extraction and liquid chromatography–tandem mass spectrometry method for the analysis of morphine, morphine-3-glucuronide and morphine-6-glucuronide in human plasma  

Microsoft Academic Search

A bioanalytical method using automated sample transferring, automated solid phase extraction (SPE) and liquid chromatography–tandem mass spectrometry (LC-MS-MS) was developed for morphine (MOR), and its metabolites morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) in human plasma. Samples of 0.25 ml were transferred into 96-well plate using automatic liquid handler (Multiprobe™ II). Automated SPE was carried out on a 96-channel programmable liquid handling

Wilson Z. Shou; Mary Pelzer; Tom Addison; Xiangyu Jiang; Weng Naidong

2002-01-01

181

Simultaneous Quantification of Buprenorphine, Norbuprenorphine, Buprenorphine-Glucuronide and Norbuprenorphine-Glucuronide in Human Umbilical Cord by Liquid Chromatography Tandem Mass Spectrometry  

PubMed Central

A LCMS method was developed and validated for the simultaneous determination of buprenorphine (BUP), norbuprenorphine (NBUP), buprenorphine glucuronide (BUP-Gluc) and norbuprenorphine glucuronide (NBUP-Gluc) in human umbilical cord. Quantification was achieved by selected ion monitoring of precursor ions m/z 468.4 for BUP; 414.3 for NBUP; 644.4 for BUP-Gluc and 590 for NBUP-Gluc. BUP and NBUP were identified by MS2, with m/z 396, 414 and 426 for BUP, and m/z 340, 364 and 382 for NBUP. Glucuronide conjugates were identified by MS3 with m/z 396 and 414 for BUP-Gluc and m/z 340 and 382 for NBUP-Gluc. The assay was linear 1–50 ng/g. Intra, inter-day and total assay imprecision (%RSD) were <14.5%, and analytical recovery ranged from 94.1% to 112.3% for all analytes. Extraction efficiencies were >66.3%, and process efficiency >73.4%. Matrix effect ranged, in absolute value, from 3.7% to 27.4% (CV<21.8%, n=8). The method was selective with no endogenous or exogenous interferences from 41 compounds evaluated. Sensitivity was high with limits of detection of 0.8 ng/g. In order to prove method applicability, an authentic umbilical cord obtained from an opioid-dependent pregnant woman receiving BUP pharmacotherapy was analyzed. Interestingly, BUP was not detected but concentrations of the other metabolites were NBUP-Gluc 13.4 ng/g, BUP-Gluc 3.5 ng/g and NBUP 1.2 ng/g.

Concheiro, Marta; Shakleya, Diaa M.; Huestis, Marilyn A.

2009-01-01

182

Characterization of raloxifene glucuronidation: potential role of UGT1A8 genotype on raloxifene metabolism in vivo.  

PubMed

Raloxifene is a second-generation selective estrogen receptor modulator used for the prevention and treatment of osteoporosis and the prevention of breast cancer in postmenopausal women. Raloxifene is extensively metabolized by glucuronidation to form raloxifene-6-glucuronide (ral-6-Gluc) and raloxifene-4'-glucuronide (ral-4'-Gluc). The goal of the present study was to determine whether functional polymorphisms in active UGTs could play a role in altered raloxifene glucuronidation in vivo. Using homogenates from HEK293 UGT-overexpressing cell lines, raloxifene was shown to be glucuronidated primarily by the hepatic UGTs 1A1 and 1A9 and the extra-hepatic UGTs 1A8 and 1A10; no detectable raloxifene glucuronidation activity was found for UGT2B enzymes. Functional UGT1A1 transcriptional promoter genotypes were significantly (Ptrend = 0.005) associated with ral-6-Gluc formation in human liver microsomes, and, consistent with the decreased raloxifene glucuronidation activities observed in vitro with cell lines overexpressing UGT1A8 variants, the UGT1A8*2 variant was significantly (P = 0.023) correlated with total raloxifene glucuronide formation in human jejunum homogenates. While ral-4'-Gluc exhibited 1:100th the anti-estrogenic activity of raloxifene itself as measured by binding to the estrogen receptor, raloxifene glucuronides comprised about 99% of the circulating raloxifene dose in raloxifene-treated subjects, with ral-4'-Gluc comprising ~70% of raloxifene glucuronides. Plasma ral-6-Gluc (Ptrend = 0.0025), ral-4'-Gluc (Ptrend = 0.001), and total raloxifene glucuronides (Ptrend = 0.001) were increased in raloxifene-treated subjects who were predicted slow metabolizers [UGT1A8 (*1/*3)] versus intermediate metabolizers [UGT1A8 (*1/*1) or UGT1A8 (*1/*2)] versus fast metabolizers [UGT1A8 (*2/*2). These data suggest that raloxifene metabolism may be dependent on UGT1A8 genotype and that UGT1A8 genotype may play an important role in overall response to raloxifene. PMID:23682072

Sun, Dongxiao; Jones, Nathan R; Manni, Andrea; Lazarus, Philip

2013-05-16

183

Androstane3a,17b-Diol Glucuronide as a Steroid Correlate of Visceral Obesity in Men  

Microsoft Academic Search

Plasma levels of androstane-3a,17b-diol glucuronide (3a-DIOL-G) and androsterone glucuronide (ADT-G) as well as testosterone and adrenal C19 steroid concentrations were measured in a sample of 80 men in whom visceral adipose tissue (AT) accumulation was also determined by computed tomography. Plasma 3a-DIOL-G concen- trations showed significant positive correlations with total body fat mass (r 5 0.31; P , 0.05) and

FERNAND LABRIE; ALAIN BELANGER; CLAUDE BOUCHARD; ANGELO TREMBLAY; JEAN-PIERRE DESPRES

2009-01-01

184

Non-opioid induction of morphine-6-glucuronide synthesis is elicited by prolonged exposure of rat hepatocytes to heroin  

Microsoft Academic Search

BackgroundLiver metabolism of morphine leads to the formation of morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G), the latter possessing strong opioid activity that however differs from that of the parent compound. In previous studies conducted in rats we have shown that repeated in vivo exposure to phenanthrene class of mu opioid receptor (MOR) agonists or antagonists (heroin, morphine, and naltrexone), but not

Manuela Graziani; Letizia Antonilli; Anna Rita Togna; Valentina Brusadin; Stefania Viola; Giuseppina Togna; Aldo Badiani; Paolo Nencini

2008-01-01

185

Determination of mycophenolic acid glucuronide in microsomal incubations using high performance liquid chromatography–tandem mass spectrometry  

Microsoft Academic Search

A sensitive and specific HPLC–MS\\/MS method was developed for the analysis of mycophenolic acid glucuronide (MPAG) in incubations with human liver microsomes. Incubation samples were processed by protein precipitation with acetonitrile. MPAG and the internal standard phenolphthalein glucuronide were chromatographed on a C18 Synergi Fusion-RP column (100mm×2mm, 4?m) using gradient elution with a mixture of 1mM acetic acid in deionized

Mohamed-Eslam F. Mohamed; Stephen S. Harvey; Reginald F. Frye

2008-01-01

186

Ethyl Carbamate Preventative Action Manual (Italian language ...  

Center for Food Safety and Applied Nutrition (CFSAN)

... Citrulline Production And Ethyl Carbamate (Urethane) Precursor Formation From Arginine Degradation By Wine Lactic Acid Bacteria Leuconostoc ... More results from www.fda.gov/food/foodborneillnesscontaminants/chemicalcontaminants

187

Morpholine-4-carboxamidinium ethyl carbonate  

PubMed Central

The asymmetric unit of the title salt, C5H12N3O+·C3H5O3 ?, contains two carboxamidinium and two ethyl carbonate ions. In the crystal, the C—N bond lengths in the central CN3 units of the cations range between 1.324?(2) and 1.352?(2)?Å, indicating partial double-bond character. The central C atoms are bonded to the three N atoms in a nearly ideal trigonal–planar geometry and the positive charges are delocalized in the CN3 planes. The morpholine rings are in chair conformations. The C—O bond lengths in both ethyl carbonate ions are characteristic for delocalized double bonds [1.243?(2)–1.251?(2)?Å] and typical single bonds [1.368?(2) and 1.375?(2)?Å]. In the crystal, N—H?O hydrogen bonds between cations and anions generate a two-dimensional network in the ac plane.

Tiritiris, Ioannis

2012-01-01

188

Hormonal monitoring of early pregnancy by a direct radioimmunoassay of steroid glucuronides in first morning urine  

SciTech Connect

The usefulness of the direct 4-hour radioimmunoassay of estriol-16-glucuronide (E/sub 3/G) and pregnanediol-3-glucuronide (P/sub 2/G) in first morning urine (FMU) for establishing a prognosis of the early pregnancy outcome was evaluated in 106 patients that became pregnant. Microaliquots of FMU were serially assayed from day 3 of the conception cycle until day 80 of pregnancy. The E/sub 3/G and P/sub 2/G profiles of 19 pregnancies which terminated in spontaneous abortion with either a diagnosis of the blighted ovum syndrome (n = 11) or presumption of a corpus luteum/trophoblast failure (n = 8) have been compared with those of clinically normal pregnancies (n = 87). Normal pregnancies displayed typical patterns of E/sub 3/G and P/sub 2/G development, while variations were observed in abortive events that reflected changes of the fetoplacental unit.

Mendizabal, A.F.; Quiroga, S.; Farinati, Z.; Lahoz, M.; Nagle, C.

1984-11-01

189

Gender and oral contraceptive steroids as determinants of drug glucuronidation: effects on clofibric acid elimination.  

PubMed Central

The disposition of clofibric acid, a drug metabolised largely by glucuronidation, was studied in eight males, eight females and eight females receiving oral contraceptive steroids (OCS). Clofibric acid plasma clearance was not significantly different in males compared to the control female group but was 48% greater (P less than 0.01) in women receiving OCS compared to non-pill using females. This difference was due to an alteration in clofibric acid metabolic clearance as there were no differences between the groups in clofibric acid free fraction. Along with previous data the results suggest that induction of drug glucuronidation by OCS may be of clinical importance, although any sex-related differences are unlikely to be of clinical significance.

Miners, J O; Robson, R A; Birkett, D J

1984-01-01

190

Synthesis and biological evaluations of a monomethylauristatin E glucuronide prodrug for selective cancer chemotherapy.  

PubMed

We developed a glucuronide prodrug of the potent monomethylauristatin E (MMAE). This prodrug is significantly less toxic than the parent drug. However, in the presence of ?-glucuronidase the prodrug leads to the efficient release of MMAE thereby triggering a subnanomolar cytotoxic activity against several cancer cell lines. Preliminary in vivo experiments conducted in C57BL/6 mice bearing a subcutaneous murine Lewis Lung Carcinoma (LLC) demonstrated the potential of this targeting system for the selective treatment of solid tumors. PMID:23845743

Legigan, Thibaut; Clarhaut, Jonathan; Renoux, Brigitte; Tranoy-Opalinski, Isabelle; Monvoisin, Arnaud; Jayle, Christophe; Alsarraf, Jérôme; Thomas, Mikaël; Papot, Sébastien

2013-06-25

191

Wheel running attenuates the antinociceptive properties of morphine and its metabolite, morphine-6-glucuronide, in rats  

Microsoft Academic Search

Recent work has shown that chronic exercise is associated with a reduction in the pain-relieving actions of opioid drugs in experimental animals. To determine whether this reduction represents an interaction between exogenously administered opioids and the endogenous opioid system, or is the result of altered drug pharmacokenitics, the antinociceptive actions of morphine and its metabolite, morphine-6-glucuronide (M6G), were compared in

Wendy Foulds Mathes; Robin B Kanarek

2001-01-01

192

Androsterone glucuronide is a marker of adrenal hyperandrogenism in hirsute women.  

PubMed

Androsterone glucuronide (Andros-G), a dihydrotestosterone metabolite, is present in serum at concentrations at least tenfold greater than those of androstanediol glucuronide. To investigate the significance of serum androsterone glucuronide, we developed a direct radioimmunoassay for this compound and measured its levels in normal women, women with mild or severe idiopathic hirsutism (IH), hirsute women with polycystic ovarian syndrome (PCO), and non-hirsute obese women. To determine the source of Andros-G precursors, serum levels were measured before and after selective ovarian suppression with leuprolide, combined ovarian and adrenal suppression with leuprolide and dexamethasone, and adrenal stimulation with ACTH. Androsterone glucuronide levels (nmol/l; mean +/- SD) were significantly higher (P less than 0.025) in women with mild idiopathic hirsutism (IH) (185 +/- 91), severe IH (173 +/- 97), and hirsute women with polycystic ovarian syndrome (PCO) (178 +/- 102) than in normal women (110 +/- 26). Levels in non-hirsute obese women (64 +/- 19) were lower than in normal women (P less than 0.01). Baseline levels (mean +/- SEM) in hirsute women given 20 micrograms/kg/day leuprolide for 5-9 months (171 +/- 15) were not significantly changed after leuprolide alone (153 +/- 18), and were decreased after adding dexamethasone (19 +/- 6; P less than 0.001). Andros-G levels did not increase significantly in normal women 60 min after i.v. ACTH (112 +/- 14 to 126 +/- 19), but rose in IH (170 +/- 24 to 216 +/- 26; P less than 0.001) and in PCO (179 +/- 26 to 238 +/- 31; P = 0.002). We conclude that Andros-G in women arises primarily from adrenal gland precursors and is elevated in hirsute women as a group. Its levels do not correlate with the severity of hirsutism, or the presence or absence of PCO, but reflect an increased production of adrenal androgens in both IH and PCO. PMID:2160872

Thompson, D L; Horton, N; Rittmaster, R S

1990-03-01

193

Urinary pharmacokinetics of the glucuronide and sulfate conjugates of genistein and daidzein.  

PubMed

Consumption of soybean-rich diets is thought to provide significant health benefits such as prevention of cancer, primarily because of the high contents of factors such as the isoflavones genistein and daidzein. Isoflavones circulate and are excreted into the urine mainly as glucuronide and sulfate conjugates. This study was conducted to determine the urinary pharmacokinetics of sulfate and glucuronide conjugates of genistein and daidzein. Twelve volunteers consumed a soy beverage providing 1 and 0.6 mg/kg body weight of genistein and daidzein equivalents, respectively. Urine was collected at various times during the 48 h after soy consumption and was digested with either glucuronidase or sulfatase, and the liberated aglycones were extracted and analyzed by liquid chromatography-mass spectrometry. Urinary isoflavone sulfate levels were determined by two methods: (a) assessment of aglycone after sulfatase hydrolysis (measured); or (b) calculated by subtracting the aglycone + glucuronide levels from the total urinary isoflavone levels. The apparent terminal half-life for daidzein sulfate (3.9+/-0.5 h) that was determined from sulfatase-treated urine was 32% shorter (P < or = 0.02) than that of the calculated daidzein sulfate (5.7+/-0.08 h). A similar trend was obtained for genistein sulfate (4.5+/-0.7 versus 6.8+/-0.1 h). The apparent terminal half-lives for genistein and daidzein glucuronides were 6.0+/-0.4 and 3.8+/-0.4 h, respectively. These data suggest that the measured urinary isoflavone sulfate values provide a better understanding of the pharmacokinetics than the calculated values. Additional studies are needed to determine whether the apparent terminal half-lives can be attributed to elimination or absorption processes. PMID:10794486

Shelnutt, S R; Cimino, C O; Wiggins, P A; Badger, T M

2000-04-01

194

Menthol-?-D-Glucuronide: A Potential Prodrug for Treatment of the Irritable Bowel Syndrome  

Microsoft Academic Search

Menthol-ß-D-glucuronide is a potential prodrug for colonic delivery of the spasmolytic agent menthol. Menthol is the primary constituent of peppermint oil, which is used to treat the irritable bowel syndrome. The chemical stability of menthol-ß-D-glucuromde was assessed at various pHs (1.5,4.5, 6.0 and 7.4) over a 4 to 24 h period at 37°C. The prodrug was stable, i.e., there was

Harold W. Nolen III; David R. Friend

1994-01-01

195

Androgen glucuronides, instead of testosterone, as the new markers of androgenic activity in women.  

PubMed

Despite the long series of cohort studies performed during the last 20 years, the correlation between serum testosterone and any clinical situation believed to be under androgen control in women has remained elusive. This is likely related to the recent finding that the androgens made locally in large amounts in peripheral tissues from the precursor dehydroepiandrosterone (DHEA) act in the same cells where synthesis takes place and are not released in significant amounts in the circulation, thus making unreliable the measurement of serum testosterone as marker of total androgenic activity. The objective is to determine if serum androgen glucuronides can be replaced by testosterone or another steroid as measure of androgenic activity. Since the glucuronide derivatives of androgens are the obligatory route of elimination of all androgens, these metabolites were measured by liquid chromatography tandem mass spectrometry under basal conditions in 377 healthy postmenopausal women aged 55-65 years as well as in 47 premenopausal women aged 30-35 years while testosterone was assayed by gas chromatography mass spectrometry. No correlation was found between the serum concentration of testosterone and that of androsterone glucuronide (ADT-G) or androstenediol glucuronide (3alpha-diol-G), the androgen metabolites which account for the total pool of androgens. The present data show that measurement of the total pool of androgens reflected by the serum levels of ADT-G and 3alpha-diol-G cannot be replaced by serum testosterone or any other steroid, including DHEA or DHEA sulphate. These findings may have implications for women with androgen deficiency involving osteoporosis, obesity, type 2 diabetes, sexual dysfunction, loss of muscular strength and a series of other clinical situations affecting women's health. Measuring ADT-G and 3alpha-diol-G might identify cases of true androgen deficiency and provide an opportunity to offer appropriate androgen therapy. PMID:16621522

Labrie, Fernand; Bélanger, Alain; Bélanger, Patrick; Bérubé, René; Martel, Céline; Cusan, Leonello; Gomez, José; Candas, Bernard; Castiel, Isabelle; Chaussade, Véronique; Deloche, Claire; Leclaire, Jacques

2006-04-18

196

Direct radioiodination of metabolic 8-hydroxy-quinolyl-glucuronide, as a potential anti-cancer drug  

Microsoft Academic Search

8-Hydroxy-quinolyl-glucuronide (8-HOQ-Glu) can be deglucuronidated by the ?-glucoronidase enzyme, which has an activity that is considerably high in certain kinds of cancer cell. Owing to this enzyme activity, 8-HOQ-Glu can be considered as a potential anti-cancer drug. The combination of the radiotoxicity known of 125I nuclide with the cytotoxicity of 8-hydroxy-quinoline (8-HOQ) and particularly the selective carrying of 125I into

Turan Ünak

1996-01-01

197

Synthesis of an estradiol glucuronide derivative and investigation of its radiopharmaceutical potential  

Microsoft Academic Search

The aim of the current study was to synthesize a derivative of estradiol glucuronide, which is able to be labeled with 99mTc and to investigate its radiopharmaceutical potential using imaging and biodistribution studies. An estrogen derivative, ?-estradiol (1,3,5,[10]-estratriene-3,17?-diol) attached to diethylenetriamine pentaacetic acid (DTPA) was synthesized in six steps. At the end of these steps a compound of estradiol and

F. Z. Biber; P. Unak; T. Ertay; E. I. Medine; F. Zihnioglu; C. Tasc?; H. Durak

2006-01-01

198

Extensive intestinal glucuronidation of raloxifene in vivo in pigs and impact for oral drug delivery.  

PubMed

In this study an advanced multisampling site pig model, with simultaneous venous blood sampling pre- and post liver, was applied to quantify the role of the intestine in relation to the liver in first-pass glucuronidation of raloxifene in vivo. The pharmacokinetic of raloxifene (a BCS/BDDCS class II compound) in humans is characterized by extensive metabolism (>90%) and the major metabolite is the 4'-?-glucuronide (R-4-G). Following intra-jejunal (i.j.) single dose administration in pigs raloxifene was metabolized in the gut (E(G)) during first-pass to more than 70% and a high concentration (AUC(0-6 h) ratio R-4-G/raloxifene >100) of R-4-G was reached in the portal vein. The hepatic extraction (E(H)) of raloxifene was ~50% and as in humans the bioavailability become low (~7%) in pigs. Interestingly the E(H) of raloxifene and R-4-G was time-dependent after i.j. administration. It is clear that the gut was the dominating organ in first-pass extraction of raloxifene in vivo in pigs. The quantification in this study support earlier human data and emphasize that intestinal glucuronidation should be considered early in the pharmaceutical development. PMID:22559211

Thörn, Helena Anna; Yasin, Mohammed; Dickinson, Paul Alfred; Lennernäs, Hans

2012-05-04

199

Changes in Transpiration induced by Ethyl Alcohol  

Microsoft Academic Search

ETHYL alcohol was used as an auxiliary solvent in the preparation of auxin solutions for a series of transpiration experiments with plants in water culture when the roots were supplied with different auxins at varying concentrations. This method appears to be fairly common for auxin studies1,2. After weighing, the auxin is dissolved in a small quantity of ethyl alcohol, and

S. Allerup

1962-01-01

200

Piperidine-1-carboxamidinium ethyl carbonate  

PubMed Central

In the title salt, C6H14N3 +·C3H5O3 ?, the C—N bond lengths in the central CN3 unit of the carboxamidinium cation are 1.3262?(18), 1.3359?(18) and 1.3498?(18)?Å, indicating partial double-bond character. The central C atom is bonded to the three N atoms in a nearly ideal trigonal–planar geometry and the positive charge is delocalized in the CN3 plane. The piperidine ring is in a chair conformation. The C—O bond lengths in the ethyl carbonate anion are characteristic for a delocalized double bond and a typical single bond. In the crystal, N—H?O hydrogen bonds between cations and anions generate a two-dimensional network in the direction of the ab plane, whereas adjacent ion pairs form chains running along the b axis.

Tiritiris, Ioannis

2012-01-01

201

Regiospecificity of human UDP-glucuronosyltransferase isoforms in chalcone and flavanone glucuronidation determined by metal complexation and tandem mass spectrometry.  

PubMed

The glucuronidation of a series of chalcones (2'-hydroxychalcone, 2',4'-dihydroxychalcone, 3,2'-dihydroxychalcone, 4,2'-dihydroxychalcone, and cardamonin) and their corresponding cyclized flavanones (7-hydroxyflavanone, 3'-hydroxyflavanone, 4'-hydroxyflavanone, and alpinetin) by eight human UDP-glucuronosyltransferase (UGT) 1A enzymes was evaluated. A postcolumn metal complexation LC-MS/MS strategy was used successfully to produce characteristic mass spectrometric product ions that were utilized in combination with elution order trends to identify chalcone and flavanone monoglucuronides unambiguously, thus allowing determination of the regioselectivities of the UGT1A isoforms. The presence of hydroxy groups on the A- or B-ring had a significant effect on the glucuronide product yield and the site where glucuronidation occurred. For example, for reaction with UGT1A9, formation of the 2'-O-glucuronide was increased for dihydroxychalcones with A-ring hydroxy substituents. In contrast, although UGT1A8 reacted with 3,2'-dihydroxychalcone and 4,2'-dihydroxychalcone to yield 2'-O-glucuronide products, the presence of a B-ring hydroxy group at the 4' position on cardamonin and 2',4'-dihydroxychalcone quenched the reaction at the OH-2' position. Moreover, the A-ring OH-4 group promoted glucuronidation at the 2' position for the reaction of 4,2'-dihydroxychalcone with UGT1A1 and 1A3. For UGT1A7, hydroxy group substituents on the chalcone A-ring also promoted cyclization and formation of the corresponding flavanone glucuronide. PMID:23713759

Niemeyer, Emily D; Brodbelt, Jennifer S

2013-05-29

202

40 CFR 180.441 - Quizalofop ethyl; tolerances for residues.  

Code of Federal Regulations, 2013 CFR

...Tolerances are established for residues of the herbicide quizalofop ethyl, including its...Tolerances are established for residues of the herbicide quizalofop ethyl, including...registration are established for residues of the herbicide quizalofop ethyl,...

2013-07-01

203

Systematic Studies of Sulfation and Glucuronidation of 12 Flavonoids in the Mouse Liver S9 Fraction Reveals both Unique and Shared Positional Preferences  

PubMed Central

Sulfation and glucuronidation are the principal metabolic pathways of flavonoids, and extensive phase II metabolism is the main reason for their poor bioavailabilities. The purpose of this study was to compare the similarities and differences in the positional preference of glucuronidation versus sulfation in the mouse liver S9 fraction. The conjugating rates of seven mono-hydroxyflavones (HFs) (i.e., 2’-, 3’-, 4’-, 3-, 5-, 6-, and 7-HF), and five di-hydroxyflavones (diHFs), (i.e., 6,7-, 4’,7-, 3,7-, 5,7-, and 3,4’-diHF) were determined in three separate enzymatic reaction systems: (A) sulfation only, (B) glucuronidation only, or (C) simultaneous sulfation and glucuronidation (i.e., Sult-Ugt co-reaction). In general, glucuronidation rates were much faster than the sulfation rates. Among the HFs, 7-HF was the best substrate for both conjugation reactions, whereas 3-HF was rapidly glucuronidated but was not sulfated. As a result, the rank order of sulfation was very different from that of glucuronidation. Among the diHFs, regiospecific glucuronidation was limited to 7-OH and 3-OH positions, whereas regiospecific sulfation was limited to 7-OH and 4’-OH positions. Other positions (i.e., 6-OH and 5-OH) in diHFs were not conjugated. The positional preferences were essentially maintained in a Sult-Ugt co-reaction system, although sulfation was surprisingly enhanced. Lastly, sulfation and glucuronidation displayed different regiospecific- and substrate-dependent characteristics. In conclusion, glucuronidation and sulfation shared the same preference for 7-OH position (of flavonoids) but displayed unique preference in other positions in that glucuronidation preferred 3-OH position whereas sulfation preferred 4’-OH position.

Tang, Lan; Zhou, Juan; Yang, Cai-Hua; Xia, Bi-Jun; Hu, Ming; Liu, Zhong-Qiu

2012-01-01

204

Resveratrol 3-O-d-glucuronide and resveratrol 4'-O-d-glucuronide inhibit colon cancer cell growth: Evidence for a role of A3 adenosine receptors, cyclin D1 depletion, and G1 cell cycle arrest.  

PubMed

SCOPE: Resveratrol is a plant-derived polyphenol with chemotherapeutic properties in animal cancer models and many biochemical effects in vitro. Its bioavailability is low and raises the possibility that the metabolites of resveratrol have biological effects. Here we investigate the actions of resveratrol 3-O-d-glucuronide, resveratrol 4'-O-d-glucuronide, and resveratrol 3-O-d-sulfate on the growth of colon cancer cells in vitro. METHODS AND RESULTS: The growth of Caco-2, HCT-116, and CCL-228 cells was measured using the neutral red and MTT assays. Resveratrol and each metabolite inhibited cell growth with IC50 values of 9.8-31 ?M. Resveratrol caused S phase arrest in all three cell lines. Resveratrol 3-O-d-glucuronide and resveratrol 4'-O-d-glucuronide caused G1 arrest in CCL-228 and Caco-2 cells. Resveratrol 3-O-d-sulfate had no effect on cell cycle. Growth inhibition was reversed by an inhibitor of AMP-activated protein kinase (compound C) or an adenosine A3 receptor antagonist (MRS1191). The A3 receptor agonist 2Cl-IB-MECA inhibited growth and A3 receptors were detected in all cell lines. The resveratrol glucuronides also reduced cyclin D1 levels but at higher concentrations than in growth experiments and generally did not increase phosphorylated AMP-activated protein kinase. CONCLUSION: Resveratrol glucuronides inhibit cell growth by G1 arrest and cyclin D1 depletion, and our results strongly suggest a role for A3 adenosine receptors in this inhibition. PMID:23650147

Polycarpou, Elena; Meira, Lisiane B; Carrington, Simon; Tyrrell, Elizabeth; Modjtahedi, Helmout; Carew, Mark A

2013-05-01

205

Androstanediol glucuronide isomers in normal men and women and in men infused with labeled dihydrotestosterone  

SciTech Connect

3 alpha-Androstanediol glucuronide (Adiol G) is a major metabolite of dihydrotestosterone (DHT). Adiol G actually represents 2 different compounds, since the glucuronide can be conjugated at the 3-carbon position (Adiol 3-G) or at the 17-carbon position (Adiol 17-G). To determine which glucuronide represents the predominant physiological DHT metabolite and which isomer is the major circulating form, we developed a RIA to directly measure Adiol 3-G in serum extracts. In 10 normal men, mean serum Adiol 3-G and total Adiol G levels were 4.44 +/- 0.49 (+/- SE) nmol/L (208 +/- 23 ng/dL) and 27.9 +/- 2.8 nmol/L (1310 +/- 129 ng/dL), respectively (13.9 +/- 3.0% of Adiol G was Adiol 3-G). In 10 normal women sampled during the early follicular phase, mean serum Adiol 3-G and total Adiol G levels were 2.64 +/- 0.64 nmol/L (124 +/- 30 ng/dL) and 14.9 +/- 1.5 nmol/L (697 +/- 69 ng/dL), respectively (17.4 +/- 3.6% of Adiol G was Adiol 3-G). In 4 normal men infused for 8 h with tritiated DHT, 17.4 +/- 3.4% of the resulting tritiated Adiol G was Adiol 3-G. These results indicate that Adiol 17-G is the predominant circulating form of Adiol G in normal men and women and that it is also the major Adiol G isomer derived from DHT.

Rittmaster, R.S.; Thompson, D.L.; Listwak, S.; Loriaux, D.L.

1988-01-01

206

Inhibition of genistein glucuronidation by bisphenol A in human and rat liver microsomes.  

PubMed

Genistein is a natural phytoestrogen of the soybean, and bisphenol A (BPA) is a synthetic chemical used in the production of polycarbonate plastics. Both genistein and BPA disrupt the endocrine system in vivo and in vitro. Growing concerns of altered xenobiotic metabolism due to concomitant exposures from soy milk in BPA-laden baby bottles has warranted the investigation of the glucuronidation rate of genistein in the absence and presence (25 ?M) of BPA by human liver microsomes (HLM) and rat liver microsomes (RLM). HLM yield V(max) values of 0.93 ± 0.10 nmol · min(-1) · mg(-1) and 0.62 ± 0.05 nmol · min(-1) · mg(-1) in the absence and presence of BPA, respectively. K(m) values for genistein glucuronidation by HLM in the absence and presence of BPA are 15.1 ± 7.9 ?M and 21.5 ± 7.7 ?M, respectively, resulting in a K(i) value of 58.7 ?M for BPA. Significantly reduced V(max) and unchanged K(m) in the presence of BPA in HLM are suggestive of noncompetitive inhibition. In RLM, the presence of BPA resulted in a K(i) of 35.7 ?M, an insignificant change in V(max) (2.91 ± 0.26 nmol · min(-1) · mg(-1) and 3.05 ± 0.41 nmol · min(-1) · mg(-1) in the absence and presence of BPA, respectively), and an increase in apparent K(m) (49.4 ± 14 ?M with no BPA and 84.0 ± 28 ?M with BPA), indicative of competitive inhibition. These findings are significant because they suggest that BPA is capable of inhibiting the glucuronidation of genistein in vitro, and that the type of inhibition is different between HLM and RLM. PMID:22146138

Coughlin, Janis L; Thomas, Paul E; Buckley, Brian

2011-12-06

207

Influence of glucuronidation and reduction modifications of resveratrol on its biological activities.  

PubMed

Resveratrol (3,5,4'-trihydroxystilbene, RES), a star among dietary polyphenols, shows a wide range of biological activities, but it is rapidly and extensively metabolized into its glucuronide and sulfate conjugates as well as to the corresponding reduced products. This begs the question of whether the metabolites of RES contribute to its in vivo biological activity. To explore this possibility, we synthesized its glucuronidation (3-GR and 4'-GR) and reduction (DHR) metabolites, and evaluated the effect of these structure modifications on biological activities, including binding ability with human serum albumin (HSA), antioxidant activity in homogeneous solutions and heterogeneous media, anti-inflammatory activity, and cytotoxicity against various cancer cell lines. We found that 1) 4'-GR, DHR and RES show nearly equal binding to HSA, mainly through hydrogen bonding, whereas 3-GR adopts a quite different orientation mode upon binding, thereby resulting in reduced ability; 2) 3-GR shows comparable (even equal) ability to RES in FRAP- and AAPH-induced DNA strand breakage assays; DHR, 3-GR, and 4'-GR exhibit anti-hemolysis activity comparable to that of RES; additionally, 3-GR and DHR retain some degree activity of the parent molecule in DPPH.-scavenging and cupric ion-initiated oxidation of LDL assays, respectively; 3) compared to RES, 4'-GR displays equipotent ability in the inhibition of COX-2, and DHR presents comparable activity in inhibiting NO production and growth of SMMC-7721 cells. Relative to RES, its glucuronidation and reduction metabolites showed equal, comparable, or some degree of activity in the above assays, depending on the specific compound and test model, which probably supports their roles in contributing to the in vivo biological activities of the parent molecule. PMID:23703900

Lu, Dong-Liang; Ding, De-Jun; Yan, Wen-Jing; Li, Ran-Ran; Dai, Fang; Wang, Qi; Yu, Sha-Sha; Li, Yan; Jin, Xiao-Ling; Zhou, Bo

2013-05-23

208

In Vitro Glucuronidation of Fenofibric Acid by Human UDP-Glucuronosyltransferases and Liver Microsomes  

PubMed Central

Fenofibric acid (FA), the active moiety of fenofibrate, is an agonist of the peroxisome proliferator-activated nuclear receptor ? that modulates triglyceride and cholesterol profiles. Lipid response to fenofibrate and FA serum concentrations is highly variable. Although FA is reported to be almost exclusively inactivated by UDP-glucuronosyltransferases (UGTs) into FA-glucuronide (FA-G), the contribution of UGT isoenzymes has never been systematically assessed. Heterologously expressed human UGT1A and UGT2B and their coding variants were tested for FA glucuronidation using liquid chromatography/mass spectrometry. Recombinant UGT2B7 presented the highest Vmax/Km value (2.10 ?l/min/mg), 16-fold higher than the activity of other reactive UGTs, namely, UGT1A3, UGT1A6, and UGT1A9 (0.13, 0.09, and 0.02 ?l/min/mg, respectively). UGT2B7.1 (His268) and UGT2B7.2 (Tyr268) enzyme activity was similar, whereas UGT1A3.2 (R11A47), UGT1A3.3 (Trp11), and UGT1A9.3 (Thr33) showed 61 to 96% reduced Vmax/Km values compared with the respective (1) reference proteins. FA-G formation by a human liver bank (n = 48) varied by 10-fold, but the rate of formation was not associated with common genetic variations in UGT1A3, UGT1A6, UGT1A9, and UGT2B7. Correlation with activities for the probe substrates zidovudine (UGT2B7; r2 = 0.75), mycophenolic acid (UGT1A9; r2 = 0.42), fulvestrant (UGT1A3; r2 = 0.36), but not serotonin (UGT1A6; r2 = 0.06) indicated a primary role for UGT2B7 and lesser roles of UGT1A9 and UGT1A3 in hepatic FA glucuronidation. This was confirmed by a strong correlation of FA-G formation with UGT2B7 protein content and inhibition by fluconazole, a known UGT2B7 selective inhibitor. Additional studies are required to identify genetic factors contributing to the observed FA glucuronidation variability.

Tojcic, Jelena; Benoit-Biancamano, Marie-Odile; Court, Michael H.; Straka, Robert J.; Caron, Patrick

2009-01-01

209

[Toxicology of ethyl gasoline 78 and 94].  

PubMed

The authors have described clinical pictures of acute and chronic intoxication, especially toxic effect of ethyl gasoline upon nervous sytem, parenchymatous organs, and irritating effect on skin and mucous membranes. PMID:723613

Starzy?ski, Z; Szyma?ska, S; Jaraczewska, W; My?lak, Z

1978-01-01

210

Identification of Recent Cannabis Use: Whole-Blood and Plasma Free and Glucuronidated Cannabinoid Pharmacokinetics following Controlled Smoked Cannabis Administration  

PubMed Central

BACKGROUND ?9-Tetrahydrocannabinol (THC) is the most frequently observed illicit drug in investigations of accidents and driving under the influence of drugs. THC-glucuronide has been suggested as a marker of recent cannabis use, but there are no blood data following controlled THC administration to test this hypothesis. Furthermore, there are no studies directly examining whole-blood cannabinoid pharmacokinetics, although this matrix is often the only available specimen. METHODS Participants (9 men, 1 woman) resided on a closed research unit and smoked one 6.8% THC cannabis cigarette ad libitum. We quantified THC, 11-hydroxy-THC (11-OH-THC), 11-nor-9-carboxy-THC (THCCOOH), cannabidiol (CBD), cannabinol (CBN), THC-glucuronide and THCCOOH-glucuronide directly in whole blood and plasma by liquid chromatography/ tandem mass spectrometry within 24 h of collection to obviate stability issues. RESULTS Median whole blood (plasma) observed maximum concentrations (Cmax) were 50 (76), 6.4 (10), 41 (67), 1.3 (2.0), 2.4 (3.6), 89 (190), and 0.7 (1.4) ?g/L 0.25 h after starting smoking for THC, 11-OH-THC, THCCOOH, CBD, CBN, and THCCOOH-glucuronide, respectively, and 0.5 h for THC-glucuronide. At observed Cmax, whole-blood (plasma) detection rates were 60% (80%), 80% (90%), and 50% (80%) for CBD, CBN, and THC-glucuronide, respectively. CBD and CBN were not detectable after 1 h in either matrix (LOQ 1.0 ?g/L). CONCLUSIONS Human whole-blood cannabinoid data following cannabis smoking will assist whole blood and plasma cannabinoid interpretation, while furthering identification of recent cannabis intake.

Schwope, David M.; Karschner, Erin L.; Gorelick, David A.; Huestis, Marilyn A.

2013-01-01

211

Pharmacokinetics of acetaminophen, codeine, and the codeine metabolites morphine and codeine-6-glucuronide in healthy Greyhound dogs  

PubMed Central

The purpose of this study was to determine the pharmacokinetics of codeine and the active metabolites morphine and codeine-6-glucuronide after IV codeine administration and the pharmacokinetics of acetaminophen (APAP), codeine, morphine, and codeine-6-glucuronide after oral administration of combination product containing acetaminophen and codeine to dogs. Six healthy Greyhound dogs were administered 0.734 mg/kg codeine IV and acetaminophen (10.46 mg/kg mean dose) with codeine (1.43 mg/kg mean dose) orally. Blood samples were obtained at predetermined time points for the determination of codeine, morphine, and codeine-6-glucuronide plasma concentrations by LC/MS and acetaminophen by HPLC with UV detection. Codeine was rapidly eliminated after IV administration (T½ =1.22 hr; clearance=29.94 mL/min/kg; volume of distribution=3.17 L/kg) with negligible amounts of morphine present, but large amounts of codeine-6-glucuronide (CMAX=735.75 ng/mL) were detected. The oral bioavailability of codeine was 4%, morphine concentrations were negligible, but large amounts of codeine-6-glucuronide (CMAX=1952.86 ng/mL) were detected suggesting substantial first pass metabolism. Acetaminophen was rapidly absorbed (CMAX=6.74 ?g/mL; TMAX=0.85 hr) and eliminated (T½=0.96 hr). In conclusion, the pharmacokinetics of codeine were similar to other opioids in dogs with a short half-life, rapid clearance, large volume of distribution, and poor oral bioavailability. High concentrations of codeine-6-glucuronide were detected after IV and oral administration.

KuKanich, Butch

2009-01-01

212

Peanut variety response to postemergence applications of carfentrazone-ethyl and pyraflufen-ethyl  

Microsoft Academic Search

Field experiments were conducted in the south Texas and Texas High Plains area in 2005 and 2006 to evaluate peanut variety tolerance to carfentrazone-ethyl and pyraflufen-ethyl. Lactofen was used as the standard. Carfentrazone-ethyl at 0.03 and 0.04kgai\\/ha, pyraflufen-ethyl at 0.003 and 0.004kgai\\/ha, and lactofen at 0.22kgai\\/ha were applied 35 days after planting (DAP) in south Texas and 51–56 DAP in

W. James Grichar; Peter A. Dotray; T. A. Baughman

2010-01-01

213

Antimicrobial and demelanizing activity of Ganoderma lucidum extract, p-hydroxybenzoic and cinnamic acids and their synthetic acetylated glucuronide methyl esters.  

PubMed

Mushroom extracts or isolated compounds may be useful in the search of new potent antimicrobial agents. Herein, it is described the synthesis of protected (acetylated) glucuronide derivatives of p-hydroxybenzoic and cinnamic acids, two compounds identified in the medicinal mushroom Ganoderma lucidum. Their antimicrobial and demelanizing activities were evaluated and compared to the parent acids and G. lucidum extract. p-Hydroxybenzoic and cinnamic acids, as also their protected glucuronide derivatives revealed high antimicrobial (antibacterial and antifungal) activity, even better than the one showed by commercial standards. Despite the variation in the order of parent acids and the protected glucuronide derivatives, their antimicrobial activity was always higher than the one revealed by the extract. Nevertheless, the extract was the only one with demelanizing activity against Aspergillus niger. The acetylated glucuronide derivatives could be deprotected to obtain glucuronide metabolites, which circulate in the human organism as products of the metabolism of the parent compounds. PMID:23607932

Heleno, Sandrina A; Ferreira, Isabel C F R; Esteves, Ana P; ?iri?, Ana; Glamo?lija, Jasmina; Martins, Anabela; Sokovi?, Marina; Queiroz, Maria João R P

2013-04-19

214

Preparation, characterisation and gas transport properties of trifluoroacetylated ethyl cellulose  

Microsoft Academic Search

A mixed ester of ethyl cellulose (EC) has been prepared by reaction of trifluoroacetic anhydride with the residual hydroxy groups of ethyl cellulose. The mixed ester is soluble in tetrahydrofuran, dichloromethane, chloroform, benzene and pyridine. FTIR and NMR spectra show that hydroxy groups of ethyl cellulose were replaced by trifluoroacetoxy groups. The trifluoroacetyl ethyl cellulose (TFAEC) has higher selectivity for

Yang Wang; Allan J Easteal

1999-01-01

215

Simultaneous determination of THC-COOH and THC-COOH-glucuronide in urine samples by LC/MS/MS.  

PubMed

A fast method using liquid-liquid extraction and HPLC/tandem-mass spectrometry (LC/MS/MS) was developed for the simultaneous detection of 11-Nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid beta-glucuronide (THC-COOH-glucuronide) and 11-Nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in urine samples. This highly specific method, which combines chromatographic separation and MS/MS analysis, can be used for the confirmation of positive immunoassay results even without hydrolysis of the sample or derivatisation of extracts. Liquid-liquid extraction was optimised: with ethylacetate/diethylether (1:1, v/v) THC-COOH-glucuronide and THC-COOH could be extracted in one step. Molecular ions of the glucuronide (MH(+), m/z 521) and THC-COOH (MH(+), m/z 345) were generated using a PE/SCIEX turboionspray source in positive ionisation mode; specific fragmentation was performed in the collision cell of an API 365 triple-quadrupole mass spectrometer and yielded major fragments at m/z 345 (for THC-COOH-glucuronide) and m/z 327 as well as m/z 299 for both cannabinoids. Chromatographic separation was performed using a reversed-phase C8 column and gradient elution with 0.1% formic acid/1 mM ammonium formate and acetonitrile/0.1% formic acid. Retention times were 22.2 min for the glucuronide and 26.8 min for THC-COOH. After enzymatic hydrolysis of urine samples with beta-glucuronidase/arylsulfatase (37 degrees C, 5 h), THC-COOH-glucuronide was no longer detectable by LC/MS/MS in urine samples. However, the THC-COOH concentration was increased. For quantitation of THC-COOH, THC-COOH-D(3) was added to the urine samples as internal standard prior to analysis. From the difference of THC-COOH in the native urine and urine after enzymatic hydrolysis, molar concentration ratios of THC-COOH-glucuronide/THC-COOH in urine samples of cannabis users were determined and found to be between 1.3 and 4.5. PMID:10978652

Weinmann, W; Vogt, S; Goerke, R; Müller, C; Bromberger, A

2000-09-11

216

In Vitro Glucuronidation of 2,2-Bis(bromomethyl)-1,3-propanediol by Microsomes and Hepatocytes from Rats and Humans  

PubMed Central

2,2-Bis(bromomethyl)-1,3-propanediol (BMP) is a brominated flame retardant used in unsaturated polyester resins. In a 2-year bioassay BMP was shown to be a multisite carcinogen in rats and mice. Because glucuronidation is the key metabolic transformation of BMP by rats, in this study the in vitro hepatic glucuronidation of BMP was compared across several species. In addition, the glucuronidation activities of human intestinal microsomes and specific human hepatic UDP-glucuronosyltransferase (UGT) enzymes for BMP were determined. To explore other possible routes of metabolism for BMP, studies were conducted with rat and human hepatocytes. Incubation of hepatic microsomes with BMP in the presence of UDP-glucuronic acid resulted in the formation of a BMP monoglucuronide. The order of hepatic microsomal glucuronidation activity of BMP was rats, mice ? hamsters > monkeys ? humans. The rate of glucuronidation by rat hepatic microsomes was 90-fold greater than that of human hepatic microsomes. Human intestinal microsomes converted BMP to BMP glucuronide at a rate even lower than that of human hepatic microsomes. Among the human UGT enzymes tested, only UGT2B7 had detectable glucuronidation activity for BMP. BMP monoglucuronide was the only metabolite formed when BMP was incubated with suspensions of freshly isolated hepatocytes from male F-344 rats or with cryopreserved human hepatocytes. Glucuronidation of BMP in human hepatocytes was extremely low. Overall, the results support in vivo studies in rats in which BMP glucuronide was the only metabolite found. The poor glucuronidation capacity of humans for BMP suggests that the pharmacokinetic profile of BMP in humans will be dramatically different from that of rodents.

Rad, Golriz; Hoehle, Simone I.; Kuester, Robert K.

2010-01-01

217

CM2 antigen, a potential novel molecule participating in glucuronide transport on rat hepatocyte canalicular membrane  

PubMed Central

The polarized molecules predominately distributing at hepatocyte canalicular surface play a vital role in disclosing the process of bile formation and etiopathogenisis of cholestatic live diseases. Therefore, it is important to find novel polarized molecules on hepatocyte canalicular membrane. In the present study, canalicular membrane vesicles (CMVs) isolated from rat hepatocyte by density gradient centrifugation were used as immunogens to produce hybridoma and 46 strains of monoclonal antibodies (mAb) against CMVs were obtained. With a series of morphological assay methods, including immunohistochemistry, immunofluorescence and immuno-electron microscope, the antigens recognized by canalicular mAb1 (CM1) and canalicular mAb2 (CM2) were confirmed to predominately distribute at hepatocyte canalicular membrane. Transport activity assay revealed that CM2 could inhibit ATP-dependent E217?G uptake of rat hepatocyte CMVs. Meanwhile, Western blotting analysis showed that the molecular mass of CM2 antigen was approximately 110kDa, which was much less than Mr 180kDa of multidrug resistance-associated protein 2 (MRP2) involved in glucuronide transport. These data indicated that CM2 antigen might be a potential novel molecule participating in glucuronide transport on the hepatocyte canalicular membrane.

Wang, L.; Wang, J.; Zhou, X.; Li, J.; Shi, Y.; Han, Z.; Wang, X.; Li, S.; Yang, Z.; Wang, R.; Fan, D.; Han, Y.

2012-01-01

218

Nuclear receptors and endobiotics glucuronidation: the good, the bad, and the UGT.  

PubMed

The recent progresses in molecular biology and pharmacology approaches allowed the characterization of a series of nuclear receptors (NRs) as efficient regulators of uridine diphosphate glucuronosyltransferase (UGT) genes activity. These regulatory processes ensure an optimized UGT expression in response to specific endo- and/or exogenous stimuli. Many of these NRs are activated by endobiotics that also are substrates for UGTs. Thus, by activating their receptors, these endogenous substances control their own conjugation, leading to the concept that glucuronidation is an important part of feed-forward/feedback mechanisms by which bioactive molecules control their own concentrations. On the other hand, numerous studies have established the pharmacological relevance of NR-UGT regulatory pathways in the response to therapeutic ligands. The present review article aims at providing a comprehensive view of the physiological and pharmacological importance of the NR regulation of the expression and activity of endobiotics-conjugating UGT enzymes. Selected examples will illustrate how the organism profits from the feed-forward/feedback mechanisms involving NR-UGT pathways, but also how such regulatory processes are involved in the initiation and/or progression of several pathological situations. Finally, we will discuss how the present pharmacopeia involves NR-dependent regulation of endobiotics glucuronidation, and whether the unexploited NR-UGT axes could serve as pharmacological targets for novel therapeutics to restore endobiotics homeostasis. PMID:23330540

Bigo, Cyril; Caron, Sarah; Dallaire-Théroux, Amélie; Barbier, Olivier

2013-02-01

219

Isolation and determination of benzo(a)pyrene glucuronide and sulfate conjugates in soybean leaves  

SciTech Connect

BaP is metabolized in mammalian systems by the mixed function oxidase system of liver microsomes. This system catalyzes the oxidation of BaP via epoxide intermediate to phenol, diol and quinone metabolites. One of these 7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydro-BaP is thought to act as the ultimate carcinogen by binding covalently to cellular DNA. It is also known that Cunninghamella elegans oxidized BaP to its phenol, diol and quinone metabolites. In addition, the alcohols were detected as glucuronide and sulfate conjugates. These metabolites are remarkably similar to those observed in higher organisms. On the other hand, some investigators have demonstrated that plants take up BaP and anthracene from soil or culture medium containing these compounds. This paper reports the finding that soybeans grown in BaP polluted soil take it up and metabolize to its phenol, diol and the glucuronide and sulfate conjugates of the alcohols.

Negishi, T.; Nakano, M.; Kobayashi, S.; Kim, C.H.

1987-08-01

220

Determination of ajulemic acid and its glucuronide in human plasma by gas chromatography-mass spectrometry.  

PubMed

A method using gas chromatography-mass spectrometry (GC-MS) and solid-phase extraction (SPE) was developed for the determination of ajulemic acid (AJA), a non-psychoactive synthetic cannabinoid with interesting therapeutic potential, in human plasma. When using two calibration graphs, the assay linearity ranged from 10 to 750 ng/ml, and 750 to 3000 ng/ml AJA. The intra- and inter-day precision (R.S.D., %), assessed across the linear ranges of the assay, was between 1.5 and 7.0, and 3.6 and 7.9, respectively. The limit of quantitation (LOQ) was 10 ng/ml. The amount of AJA glucuronide was determined by calculating the difference in the AJA concentration before ("free AJA") and after enzymatic hydrolysis ("total AJA"). The present method was used within a clinical study on 21 patients suffering from neuropathic pain with hyperalgesia and allodynia. For example, plasma levels of 599.4+/-37.2 ng/ml (mean+/-R.S.D., n=9) AJA were obtained for samples taken 2 h after the administration of an oral dose of 20 mg AJA. The mean AJA glucuronide concentration at 2h was 63.8+/-127.9 ng/ml. PMID:15866495

Batista, Catarina; Berisha, Myftar; Karst, Matthias; Salim, Kahlid; Schneider, Udo; Brenneisen, Rudolf

2005-04-12

221

Purification of ethyl docosahexaenoate by selective alcoholysis of fatty acid ethyl esters with immobilized Rhizomucor miehei lipase  

Microsoft Academic Search

Ethyl docosahexaenoate (E-DHA) is efficiently enriched by the selective alcoholysis of ethyl esters originating from tuna\\u000a oil with lauryl alcohol using immobilized lipase. Alcoholysis of ethyl esters by immobilized Rhizopus delemar lipase raised the E-DHA content in the unreacted ethyl ester fraction from 23 to 49 mol% in 90% yield. However, the content\\u000a of ethyl eicosapentaenoate (E-EPA) was higher than

Yuji Shimada; Kazuaki Maruyama; Akio Sugihara; Takashi Baba; Sadao Komemushi; Shigeru Moriyama; Yoshio Tominaga

1998-01-01

222

Associations between polymorphisms in glucuronidation and sulfation enzymes and sex steroid concentrations in premenopausal women in the United States  

Microsoft Academic Search

Glucuronidation, catalyzed by UDP-glucuronosyltransferases (UGT) and sulfation, catalyzed by sulfotransferases (SULT), are pathways through which sex steroids are metabolized to less active compounds. These enzymes are highly polymorphic and genetic variants frequently result in higher or lower activity. The phenotypic effects of these polymorphisms on circulating sex steroids in premenopausal women have not yet been investigated. One hundred and seventy

Mellissa Yong; Stephen M. Schwartz; Charlotte Atkinson; Karen W. Makar; Sushma S. Thomas; Frank Z. Stanczyk; Kim C. Westerlind; Katherine M. Newton; Victoria L. Holt; Wendy M. Leisenring; Johanna W. Lampe

2011-01-01

223

Human and Rat ABC Transporter Efflux of Bisphenol A and Bisphenol A Glucuronide: Interspecies Comparison and Implications for Pharmacokinetic Assessment  

EPA Science Inventory

Significant interspecies differences exist between human and rodent with respect to absorption, distribution, and excretion of bisphenol A (BPA) and its primary metabolite, BPA-glucuronide (BPA-G). ATP-Binding Cassette (ABC) transporter enzymes play important roles in these physi...

224

Identification of glucuronide metabolites of T-2 toxin and diacetoxyscirpenol in the bile of isolated perfused rat liver.  

PubMed

Isolated rat livers were perfused with either 2 mg T-2 toxin or diacetoxyscirpenol (DAS) in a recirculating perfusion system. To identify glucuronide conjugates, equal amounts of bile samples were incubated with and without (control) a beta-glucuronidase preparation and analyzed by capillary gas liquid chromatography-chemical ionization mass spectrometry. Enzyme treatment of bile obtained from liver perfused with T-2 toxin resulted in the detection of a total of 954 micrograms HT-2 toxin (control 6 micrograms), demonstrating that excretion into the bile was mainly as glucuronide conjugates. Minor metabolites of T-2 toxin in bile were identified as 3'-hydroxy HT-2 toxin (TC-3), 3'-hydroxy-7-hydroxy HT-2 toxin (TC-6), and the glucuronide form of T-2 triol (trace amount). The glucuronide conjugates of monoacetoxyscirpenol (340 micrograms) and scirpenetriol (10 micrograms) were found in bile obtained from liver perfused with DAS, while nonconjugated metabolites were not detected. It is assumed that considerable amounts of T-2 toxin and DAS were metabolized biphasically. In phase I both trichothecenes were deacetylated, in phase II the metabolites were conjugated giving rise to the glucuronic acid adducts. PMID:3715863

Gareis, M; Hashem, A; Bauer, J; Gedek, B

1986-06-15

225

Inhibitory effect of azole antifungal agents on the glucuronidation of lorazepam using rabbit liver microsomes in vitro.  

PubMed

Azole antifungal agents (azoles) have inhibitory effects on the cytochrome P450. However, the effect of azoles on conjugative metabolism has not been given much attention. Lorazepam (LZP), a benzodiazepine sedative agent, is known to be metabolized by uridine 5'-diphosphate (UDP)-glucuronyltransferase. Herein we report investigation of the effect of azoles on the enzyme-kinetics of glucuronidation of lorazepam using rabbit liver microsomes in vitro. The Km and Vmax for LZP glucuronidation were determined to be 0.26+/-0.08 mM and 1.25+/-0.21 nmol/min/mg protein, respectively, when evaluated in the presence of a detergent 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate (CHAPS) (0.8 mg/mg protein). Azoles fluconazole, miconazole, and ketoconazole competitively inhibited the glucuronidation of LZP, with Ki values of 7.17+/-4.78 mM, 0.17+/-0.08 mM, and 0.092+/-0.026 mM, respectively. These results are comparable to the previously reported Ki values of azoles with zidovudine (AZT) glucuronidation (1.4, 0.18, and 0.08 mM for fluconazole, miconazole, and ketoconazole, respectively) [Sampol et al., Br. J. Clin. Pharmacol., 40, 83-86, 1995]. Therefore, in order to avoid possible side effects of LZP, the concomitant administration of LZP and azoles should be carefully evaluated. PMID:10823688

Sawamura, R; Sato, H; Kawakami, J; Iga, T

2000-05-01

226

Proteins identified as targets of the acyl glucuronide metabolite of mycophenolic acid in kidney tissue from mycophenolate mofetil treated rats  

Microsoft Academic Search

Covalent binding of the acyl glucuronide (AcMPAG) metabolite of the immunosuppressant mycophenolic acid (MPA) to proteins is considered a possible initiating event for organ toxicity. Since the kidney is involved in the formation and excretion of AcMPAG, it can be hypothesized that this tissue may be exposed to relatively high concentrations of this metabolite and would, therefore, be a particularly

Abdul R. Asif; Victor W. Armstrong; Antje Voland; Eberhard Wieland; Michael Oellerich; Maria Shipkova

2007-01-01

227

Urinary excretion of N-OH-2-amino-3-methylimidazo[4,5-f]quinoline-N-glucuronide in F344 rats is enhanced by green tea.  

PubMed

The effects of green tea on the metabolism of the food carcinogen 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) with emphasis on the formation of the detoxified glucuronides was studied. Two groups of 20 adult male and female Fischer 344 rats consumed 2% green tea or water for 6 weeks before being administered a single dose of 40 mg/kg body weight of [2-14C]IQ by oral gavage. Major metabolites in 24 h urine samples were separated by high-performance liquid chromatography (HPLC), including N-OH-IQ-N-glucuronide, 5-OH-IQ glucuronide and sulfate, IQ sulfamate and IQ itself. The structures of the main metabolites were established by mobility on the HPLC and by mass spectrometry. Sulfate esters and sulfamate were hydrolyzed by 0.1 N HCl for 15 min at 100 degrees C, yielding 5-OH-IQ and high levels of IQ. HPLC of the resulting product showed the N-OH-IQ-N-glucuronide and the 5-OH-IQ glucuronide, as well as IQ. The male and female rats drinking tea displayed a significantly higher (P < 0.05) excretion of the two major glucuronides. We conclude that intake of green tea increases the excretion of N-OH-IQ-N-glucuronide, a detoxified metabolite of the proximate carcinogen N-OH-IQ. PMID:11408354

Embola, C W; Weisburger, J H; Weisburger, M C

2001-07-01

228

Effect of UDP-glucuronosyltransferase 2B15 polymorphism on bisphenol A glucuronidation.  

PubMed

Bisphenol A (BPA) is one of a number of potential endocrine-disrupting chemicals, which are metabolized mainly by UDP-glucuronosyltransferase 2B15 (UGT2B15) in humans. Six UGT2B15 allelic variants (UGT2B15*2, UGT2B15*3, UGT2B15*4, UGT2B15*5, UGT2B15*6, and UGT2B15*7; wild-type, UGT2B15*1) with amino acid substitutions have been found in Caucasian, African-American, Hispanic, and Oriental populations to date. In this study, the effects of amino acid substitutions in UGT2B15 on BPA glucuronidation were studied using recombinant UGT2B15 enzymes of wild-type (UGT2B15.1) and all identified variants (UGT2B15.2, UGT2B15.3, UGT2B15.4, UGT2B15.5, UGT2B15.6, and UGT2B15.7) expressed in insect (Sf9) cells. The K (m), V (max), and CL (int) values of UGT2B15.1 for BPA glucuronidation were 3.9 ?M, 650 pmol/min/mg protein, and 170 ?L/min/mg protein, respectively. Although there is no significant difference in the K (m) value between wild-type and any variant UGT2B15, the V (max) and CL (int) values of UGT2B15 variants having D85Y substitution were markedly reduced to 14 and 10% for UGT2B15.2, and 4.3 and 3.9% for UGT2B15.5 compared with those of UGT2B15.1, respectively. However, the K (m), V (max), and CL (int) values of UGT2B15.3, UGT2B15.4, UGT2B15.6, and UGT2B15.7 having L86S, T352I, and/or K523T substitution(s) for BPA glucuronidation were comparable to those of UGT2B15.1. These findings suggest that D85Y substitution in UGT2B15 decreases enzymatic function and that the polymorphic alleles of UGT2B15 are closely associated with variations in the metabolism and toxicity of BPA. The information gained in this study should help with in vivo extrapolation to assess the toxicity of endocrine-disrupting chemicals. PMID:21404072

Hanioka, Nobumitsu; Oka, Hiroyuki; Nagaoka, Kenjiro; Ikushiro, Shinichi; Narimatsu, Shizuo

2011-03-15

229

Mouse hepatoma cell lines differing in aryl hydrocarbon receptor-mediated signaling have different activities for glucuronidation.  

PubMed

For studies on the aryl hydrocarbon receptor (AhR)-dependent toxicity of the mycotoxins alternariol (AOH) and alternariol methyl ether (AME), three mouse hepatoma (Hepa-1) cell lines with intact and with compromised AhR signaling were compared with respect to their activities for hydroxylation, methylation, and glucuronidation. Whereas the activities of cytochrome P450-mediated monooxygenase and catechol-O-methyl transferase were very low and did not differ between the three cell lines, a pronounced difference was observed for UDP-glucuronosyl transferase activity, which was much higher in Hepa-1c1c4 than in c1c7 and c1c12 cells. In all three cell types, the rate of glucuronidation of AOH was about four times higher than that of AME. Whereas AME caused a concentration-dependent G2/M arrest in each cell line, AOH arrested Hepa-1c1c7 and c1c12 cells but not c1c4 cells. However, Hepa-1c1c4 cells were arrested by AOH when ?-glucuronidase was added to the incubation medium in order to reverse the formation of AOH glucuronides. We conclude that the failure of AOH to cause cell cycle inhibition in Hepa-1c1c4 cells is due to its efficient glucuronidation. The considerable UDP-glucuronosyl transferase activity of Hepa-1c1c4 cells should be taken into account when other compounds are studied in this cell line. Moreover, we demonstrate that differences in glucuronide formation between cell types can be overcome by the addition of ?-glucuronidase to the cell culture medium. PMID:22143556

Burkhardt, B; Jung, S A; Pfeiffer, E; Weiss, C; Metzler, M

2011-12-06

230

Analysis of R- and S-hydroxywarfarin glucuronidation catalyzed by human liver microsomes and recombinant UDP-glucuronosyltransferases.  

PubMed

Coumadin (R-, S-warfarin) is a challenging drug to accurately dose, both initially and for maintenance, because of its narrow therapeutic range and wide interpatient variability and is typically administered as a racemic (Rac) mixture, which complicates the biotransformation pathways. The goal of the current work was to identify the human UDP-glucuronosyltransferases (UGTs) involved in the glucuronidation of the separated R- and S-enantiomers of 6-, 7-, and 8-hydroxywarfarin and the possible interactions between these enantiomers. The kinetic and inhibition constants for human recombinant 1A family UGTs toward these separated enantiomers have been assessed using high-performance liquid chromatography (HPLC)-UV-visible analysis, and product confirmations have been made using HPLC-mass spectrometry/mass spectrometry. We found that separated R- and S-enantiomers of 6-, 7-, and 8-hydroxywarfarin demonstrate significantly different glucuronidation kinetics and can be mutually inhibitory. In some cases significant substrate inhibition was observed, as shown by K(m), V(max), and K(i), comparisons. In particular, UGT1A1 and extrahepatic UGT1A10 have significantly higher capacities than other isoforms for S-7-hydroxywarfarin and R-7-hydroxywarfarin glucuronidation, respectively. Activity data generated using a set of well characterized human liver microsomes supported the recombinant enzyme data, suggesting an important (although not exclusive) role for UGT1A1 in glucuronidation of the main warfarin metabolites, including Rac-6- and 7-hydroxywarfarin and their R- and S-enantiomers in the liver. This is the first demonstration that the R- and S-enantiomers of hydroxywarfarins are glucuronidated, with significantly different enzymatic affinity and capacity, and supports the importance of UGT1A1 as the major hepatic isoform involved. PMID:21972237

Bratton, Stacie M; Mosher, Carrie M; Khallouki, Farid; Finel, Moshe; Court, Michael H; Moran, Jeffery H; Radominska-Pandya, Anna

2011-10-04

231

Analysis of R- and S-Hydroxywarfarin Glucuronidation Catalyzed by Human Liver Microsomes and Recombinant UDP-Glucuronosyltransferases  

PubMed Central

Coumadin (R-, S-warfarin) is a challenging drug to accurately dose, both initially and for maintenance, because of its narrow therapeutic range and wide interpatient variability and is typically administered as a racemic (Rac) mixture, which complicates the biotransformation pathways. The goal of the current work was to identify the human UDP-glucuronosyltransferases (UGTs) involved in the glucuronidation of the separated R- and S-enantiomers of 6-, 7-, and 8-hydroxywarfarin and the possible interactions between these enantiomers. The kinetic and inhibition constants for human recombinant 1A family UGTs toward these separated enantiomers have been assessed using high-performance liquid chromatography (HPLC)-UV-visible analysis, and product confirmations have been made using HPLC-mass spectrometry/mass spectrometry. We found that separated R- and S-enantiomers of 6-, 7-, and 8-hydroxywarfarin demonstrate significantly different glucuronidation kinetics and can be mutually inhibitory. In some cases significant substrate inhibition was observed, as shown by Km, Vmax, and Ki, comparisons. In particular, UGT1A1 and extrahepatic UGT1A10 have significantly higher capacities than other isoforms for S-7-hydroxywarfarin and R-7-hydroxywarfarin glucuronidation, respectively. Activity data generated using a set of well characterized human liver microsomes supported the recombinant enzyme data, suggesting an important (although not exclusive) role for UGT1A1 in glucuronidation of the main warfarin metabolites, including Rac-6- and 7-hydroxywarfarin and their R- and S-enantiomers in the liver. This is the first demonstration that the R- and S-enantiomers of hydroxywarfarins are glucuronidated, with significantly different enzymatic affinity and capacity, and supports the importance of UGT1A1 as the major hepatic isoform involved.

Bratton, Stacie M.; Mosher, Carrie M.; Khallouki, Farid; Finel, Moshe; Court, Michael H.; Moran, Jeffery H.

2012-01-01

232

Use of positive ion fast atom bombardment mass spectrometry for rapid identification of a bile alcohol glucuronide isolated from cerebrotendinous xanthomatosis patients  

SciTech Connect

The identification of a major biliary and plasma bile alcohol glucuronide, 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 25-tetrol-3-0-beta-D-glucuronide, present in cerebrotendinous xanthomatosis (CTX) patients, was investigated by positive ion fast atom bombardment mass spectrometry (FAB-MS). The spectrum was characterized by abundant ions formed by attachment of a proton, (M + H)+, or of alkali ions, (M + Na)+ and (M + 39K)+, to the glucuronide salt. These ions allowed an unambiguous deduction of the molecular weight of the sample. It is suggested that FAB-MS could be used in the rapid diagnosis of CTX.

Dayal, B.; Salen, G.; Tint, G.S.; Shefer, S.; Benz, S.W. (UMDNJ-New Jersey Medical School, Newark (USA))

1990-02-01

233

Uremic toxins inhibit renal metabolic capacity through interference with glucuronidation and mitochondrial respiration.  

PubMed

During chronic kidney disease (CKD), drug metabolism is affected leading to changes in drug disposition. Furthermore, there is a progressive accumulation of uremic retention solutes due to impaired renal clearance. Here, we investigated whether uremic toxins can influence the metabolic functionality of human conditionally immortalized renal proximal tubule epithelial cells (ciPTEC) with the focus on UDP-glucuronosyltransferases (UGTs) and mitochondrial activity. Our results showed that ciPTEC express a wide variety of metabolic enzymes, including UGTs. These enzymes were functionally active as demonstrated by the glucuronidation of 7-hydroxycoumarin (7-OHC; K(m) of 12±2?M and a V(max) of 76±3pmol/min/mg) and p-cresol (K(m) of 33±13?M and a V(max) of 266±25pmol/min/mg). Furthermore, a wide variety of uremic toxins, including indole-3-acetic acid, indoxyl sulfate, phenylacetic acid and kynurenic acid, reduced 7-OHC glucuronidation with more than 30% as compared with controls (p<0.05), whereas UGT1A and UGT2B protein expressions remained unaltered. In addition, our results showed that several uremic toxins inhibited mitochondrial succinate dehydrogenase (i.e. complex II) activity with more than 20% as compared with controls (p<0.05). Moreover, indole-3-acetic acid decreased the reserve capacity of the electron transport system with 18% (p<0.03). In conclusion, this study shows that multiple uremic toxins inhibit UGT activity and mitochondrial activity in ciPTEC, thereby affecting the metabolic capacity of the kidney during CKD. This may have a significant impact on drug and uremic retention solute disposition in CKD patients. PMID:23017367

Mutsaers, H A M; Wilmer, M J G; Reijnders, D; Jansen, J; van den Broek, P H H; Forkink, M; Schepers, E; Glorieux, G; Vanholder, R; van den Heuvel, L P; Hoenderop, J G; Masereeuw, R

2012-09-24

234

Bilirubin kinetics in intact rats and isolated perfused liver. Evidence for hepatic deconjugation of bilirubin glucuronides.  

PubMed Central

Most previous compartmental models describing bilirubin transport and metabolism in the liver have been validated solely by analysis of the plasma disappearance of radiolabeled bilirubin in human subjects. We now have determined the transport kinetics of a bilirubin tracer pulse by analysis of plasma, liver, and bile radioactivity data from 30 intact rats. Plasma [3H]bilirubin disappearance was best described by the sum of three exponentials, and a six-compartment model, derived by simulation analysis, was necessary and adequate to describe all experimental data. Examination of the injected radiolabeled bilirubin by extraction with hexadecyltrimethylammonium bromide and thin-layer chromatography revealed that 6.6% (mean) of the original pigment had been degraded to labeled nonbilirubin derivatives during preparation of the tracer dose. This material exhibited a significantly longer half-life (mean 50.6 min) of the plasma terminal exponential than that of authentic radiobilirubin (20.6 min). In isolated perfused rat liver, the kinetics of [3H]bilirubin in perfusate and bile readily fitted the proposed model. Compatibility of the model with the data obtained, both in the isolated liver and in vivo, required that a fraction of bilirubin conjugated in the liver be deconjugated and returned to the plasma. Deconjugation of bilirubin glucuronides was evaluated directly by infusion of bilirubin monoglucuronides, containing 14C in the glucuronosyl group, into rats with an external bile fistula. Since metabolic degradation of hydrolyzed 14C-labeled glucuronic acid yields 14CO2, this was measured in expired air. Whereas 86% of the administered labeled pigment was recovered in bile, 7% of the label appeared in 14CO2. These findings directly validate a portion of the proposed kinetic model and suggest that hepatic deconjugation of a small fraction of bilirubin glucuronides is a physiological event. Deconjugation may also account, at least in part, for the presence of increased concentrations of unconjugated bilirubin in the plasma of patients with cholestasis.

Gollan, J; Hammaker, L; Licko, V; Schmid, R

1981-01-01

235

Skin of the male African catfish, Clarias gariepinus: a source of steroid glucuronides  

SciTech Connect

Steroid metabolism in the skin of mature male African catfish, Clarias gariepinus, reared in the laboratory, was studied in vitro by tissue incubations with (/sup 3/H)pregnenolone, (/sup 3/H)dehydroepiandrosterone, (/sup 3/H)17 alpha-hydroxyprogesterone, (/sup 3/H)androstenedione, (/sup 14/C)11 beta-hydroxyandrostenedione, and (/sup 3/H)testosterone as precursors. While pregnenolone was not converted to any other steroid, dehydroepiandrosterone was transformed mainly to 5-androstene-3 beta, 17 beta-diol. The products of 17 alpha-hydroxyprogesterone incubations were 5 beta-pregnane-3 alpha,17 alpha-diol-20-one, 5 beta-pregnane-3 alpha,17 alpha, 20 beta-triol, and 5 beta-pregnan-17 alpha-o1-3,20-dione. The major steroids of androstenedione incubations were etiocholanolone, testosterone, and androsterone. Testosterone was converted mainly to etiocholanolone and androstenedione, and only small quantities of 11 beta-hydroxytestosterone, 11-ketotestosterone, and 11-ketoandrostenedione were the metabolites found in 11 beta-hydroxyandrostenedione incubation. These results demonstrated the presence of the enzymes 5 alpha- and 5 beta-reductases and 3 alpha-, 11 beta-, 17 beta-, and 20 beta-hydroxysteroid dehydrogenases in the skin. From enzymehistochemical results it appeared that the steroid conversions take place in the epithelial cells. Moreover, the presence of UDP-glucose dehydrogenase, an enzyme involved in the synthesis of glucuronic acid, in these cells indicates the possibility of steroid glucuronide formation. Indeed significant amounts of water-soluble steroid conjugates, particularly 5 beta-dihydrotestosterone- and testosterone-glucuronide, were found in the incubations with androstenedione and testosterone, indicating the presence of the UDP-glucuronosyl transferase in the catfish skin.

Ali, S.A.; Schoonen, W.G.; Lambert, J.G.; Van den Hurk, R.; Van Oordt, P.G.

1987-06-01

236

27 CFR 21.107 - Ethyl acetate.  

Code of Federal Regulations, 2013 CFR

...107 Ethyl acetate. (a) 85 percent ester: (1) Acidity (as acetic acid). Not more than 0.015 percent by weight...and none above 80 °C. (b) 100 percent ester: (1) Acidity (as acetic acid). Not more than 0.010 percent by...

2013-04-01

237

Elastic electron scattering by ethyl vinyl ether  

SciTech Connect

We report measured and calculated results for elastic scattering of low-energy electrons by ethyl vinyl ether (ethoxyethene), a prototype system for studying indirect dissociative attachment processes that may play a role in DNA damage. The integral cross section displays the expected {pi}{sup *} shape resonance. The agreement between the calculated and measured cross sections is generally good.

Khakoo, M. A.; Hong, L.; Kim, B.; Winstead, C.; McKoy, V. [Department of Physics, California State University, Fullerton, California 92834 (United States); Troy High School, 2200 Dorothy Lane, Fullerton, California 92831 (United States); A. A. Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125 (United States)

2010-02-15

238

40 CFR 180.441 - Quizalofop ethyl; tolerances for residues.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Quizalofop ethyl; tolerances for residues. ...Specific Tolerances § 180.441 Quizalofop ethyl; tolerances for residues. ...the combined residues of the herbicide quizalofop...

2010-07-01

239

40 CFR 180.441 - Quizalofop ethyl; tolerances for residues.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Quizalofop ethyl; tolerances for residues. ...Specific Tolerances § 180.441 Quizalofop ethyl; tolerances for residues. ...the combined residues of the herbicide quizalofop...

2009-07-01

240

21 CFR 172.872 - Methyl ethyl cellulose.  

Code of Federal Regulations, 2010 CFR

...Multipurpose Additives § 172.872 Methyl ethyl cellulose. The food additive methyl ethyl cellulose may be safely used in food in accordance...prescribed conditions. (a) The additive is a cellulose ether having the general formula [C6...

2009-04-01

241

21 CFR 172.872 - Methyl ethyl cellulose.  

Code of Federal Regulations, 2013 CFR

...Multipurpose Additives § 172.872 Methyl ethyl cellulose. The food additive methyl ethyl cellulose may be safely used in food in accordance...prescribed conditions. (a) The additive is a cellulose ether having the general formula [C6...

2013-04-01

242

21 CFR 172.872 - Methyl ethyl cellulose.  

Code of Federal Regulations, 2010 CFR

...Multipurpose Additives § 172.872 Methyl ethyl cellulose. The food additive methyl ethyl cellulose may be safely used in food in accordance...prescribed conditions. (a) The additive is a cellulose ether having the general formula [C6...

2010-01-01

243

21 CFR 177.1320 - Ethylene-ethyl acrylate copolymers.  

Code of Federal Regulations, 2013 CFR

...1520. (1) Specifications â(i) Infrared identification. Ethylene-ethyl acrylate...be identified by their characteristic infrared spectra. (ii) Quantitative determination...ethyl acrylate can be determined by the infrared spectra. Prepare a scan from...

2013-04-01

244

Biosynthesis of ethyl caproate and other short ethyl esters catalyzed by cutinase in organic solvent  

Microsoft Academic Search

The main objective of this work was to study the enzymatic synthesis of short chain ethyl esters, a group of relevant aroma molecules, by Fusarium solani pisi cutinase in an organic solvent media (iso-octane), and to assess the influence of different parameters on the reaction yield.Cutinase displayed high initial esterification rates in iso-octane, which amounted to 1.15?molmin?1mg?1 for ethyl butyrate

Dragana P. C. de Barros; Luís P. Fonseca; P. Fernandes; Joaquim M. S. Cabral; Ljiljana Mojovic

2009-01-01

245

Effect of galactosamine-induced hepatic UDP-glucuronic acid depletion on acetaminophen elimination in rats. Dispositional differences between hepatically and extrahepatically formed glucuronides of acetaminophen and other chemicals.  

PubMed

Galactosamine (GAL) markedly depletes hepatic UDP-glucuronic acid (UDP-GA) whereas extrahepatic UDP-GA is minimally affected. This suggests that GAL predominantly inhibits hepatic glucuronidation. Therefore, the effect of GAL-induced hepatic UDP-GA depletion was examined in bile duct-cannulated rats to determine the role of hepatic glucuronidation in the disposition of acetaminophen (AA). GAL markedly altered the fate of AA-glucuronide but had little or no effect upon other AA metabolites. GAL decreased the biliary excretion of AA-glucuronide up to 92%, whereas reductions in blood levels and urinary excretion of AA-glucuronide did not exceed 50%. This suggests that AA-glucuronide excreted in bile is predominantly of hepatic origin whereas AA-glucuronide found in blood and urine is derived from both hepatic and extrahepatic tissues. Data in the present and previous studies [Gregus, Watkins, Thompson, Klaassen: J. Pharmacol. Exp. Ther. 225, 256, (1983)] indicate that GAL greatly reduced the biliary excretion of AA- and valproic acid-glucuronide whereas the biliary excretion of the glucuronides of phenolphthalein, iopanoic acid, bilirubin, and diethylstilbestrol was only partially decreased. This difference appears to be largely due to differential contributions by the liver and extrahepatic tissues in the glucuronidation of various compounds as well as the availability of glucuronides formed in extrahepatic tissues for biliary excretion. Specifically, the extrahepatically formed glucuronide conjugates of AA and valproic acid are not readily available for biliary excretion whereas the glucuronides of the other compounds are readily excreted into bile.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2903018

Gregus, Z; Madhu, C; Goon, D; Klaassen, C D

246

Endogenous Steroid Metabolism Is Indicated by Fluctuations of Endogenous Steroid and Steroid Glucuronide Levels in Early Development of the Steelhead Trout ( Oncorhynchus mykiss)  

Microsoft Academic Search

Concentrations of endogenous steroids and their glucuronide conjugates fluctuated during early development in steelhead troutOncorhynchus mykiss.Whole body content of sex steroids and steroid glucuronides of both bisexual and gynogenetic (all female) steelhead trout were quantified by radioimmunoassay. Concentrations of 17?-estradiol (E2) and cortisol increased 2–4 days before hatch. Two days after hatch, 11-ketotestosterone (11KT) increased in concentrations in both gynogenetic

Choo-Guan Yeoh; Carl B. Schreck; Grant W. Feist; Martin S. Fitzpatrick

1996-01-01

247

Quantitation of the flavonoid wogonin and its major metabolite wogonin-7?- d-glucuronide in rat plasma by liquid chromatography–tandem mass spectrometry  

Microsoft Academic Search

This study described the application of liquid chromatography–tandem mass spectrometry for the quantitation of wogonin and its major metabolite in rat plasma. Only one conjugated metabolite with glucuronic acid was identified by chromatographic and electrospray multi-stage mass spectrometric assay. A derivatization reaction with 2-chlorethanol further demonstrated that the metabolite was wogonin-7?-d-glucuronide (W-7-G), not wogonin-5?-d-glucuronide. Other conjugated metabolites, e.g., sulfates and

Xiaoyan Chen; Hongyan Wang; Yue Du; Dafang Zhong

2002-01-01

248

Glucuronidation of dihydrotestosterone and trans-androsterone by recombinant UDP-glucuronosyltransferase (UGT) 1A4: evidence for multiple UGT1A4 aglycone binding sites.  

PubMed

UDP-glucuronosyltransferase (UGT) 1A4-catalyzed glucuronidation is an important drug elimination pathway. Although atypical kinetic profiles (nonhyperbolic, non-Michaelis-Menten) of UGT1A4-catalyzed glucuronidation have been reported occasionally, systematic kinetic studies to explore the existence of multiple aglycone binding sites in UGT1A4 have not been conducted. To this end, two positional isomers, dihydrotestosterone (DHT) and trans-androsterone (t-AND), were used as probe substrates, and their glucuronidation kinetics with HEK293-expressed UGT1A4 were evaluated both alone and in the presence of a UGT1A4 substrate [tamoxifen (TAM) or lamotrigine (LTG)]. Coincubation with TAM, a high-affinity UGT1A4 substrate, resulted in a concentration-dependent activation/inhibition effect on DHT and t-AND glucuronidation, whereas LTG, a low-affinity UGT1A4 substrate, noncompetitively inhibited both processes. The glucuronidation kinetics of TAM were then evaluated both alone and in the presence of different concentrations of DHT or t-AND. TAM displayed substrate inhibition kinetics, suggesting that TAM may have two binding sites in UGT1A4. However, the substrate inhibition kinetic profile of TAM became more hyperbolic as the DHT or t-AND concentration was increased. Various two-site kinetic models adequately explained the interactions between TAM and DHT or TAM and t-AND. In addition, the effect of TAM on LTG glucuronidation was evaluated. In contrast to the mixed effect of TAM on DHT and t-AND glucuronidation, TAM inhibited LTG glucuronidation. Our results suggest that multiple aglycone binding sites exist within UGT1A4, which may result in atypical kinetics (both homotropic and heterotropic) in a substrate-dependent fashion. PMID:20007295

Zhou, Jin; Tracy, Timothy S; Remmel, Rory P

2009-12-09

249

LC 1H NMR used for determination of the elution order of S-naproxen glucuronide isomers in two isocratic reversed-phase LCsystems  

Microsoft Academic Search

The reactive metabolite S-naproxen-?-1-O-acyl glucuronide was purified from human urine using solid phase extraction (SPE) and preparative HPLC. The structure was confirmed by 600 MHz 1H NMR. Directly coupled 600 MHz HPLC-1H NMR was used to assign the peaks in chromatograms obtained when analysing a sample containing S-naproxen aglycone and the 1-, 2-, 3-, and 4-isomers of S-naproxen-?-1-O-acyl glucuronide in

Rasmus W. Mortensen; Olivia Corcoran; Claus Cornett; Ulla G. Sidelmann; Jeff Troke; John C. Lindon; Jeremy K. Nicholson; Steen Honoré Hansen

2001-01-01

250

Synthesis, radiolabeling and In Vivo tissue distribution of an anti-oestrogen glucuronide compound, (99m)Tc-TOR-G.  

PubMed

Toremifene (TOR) has been used as an anti-oestrogen drug for the treatment and prevention of human breast cancer. The aim of this study was the addition of the hydrophilic groups diethylenetriamine pentaacetic acid (DTPA) and glucuronic acid to the starting substance TOR and to label it with technetium-99m ((99m)Tc) radionuclide and to investigate radiopharmaceutical potential of the new compound. The synthesis reactions are completed in four steps, including enzymatic reaction, with the following substeps; preparation of microsomal fraction from Hutu 80 cell line and subsequent purification of UDP-glucuronyl transferase (UDPGT), estimation of protein quantity in microsomal samples and glucuronidation reaction. The results indicate that (99m)Tc-TOR-G may be proposed as a new anti-oestrogen glucuronide imaging agent for ovarian tumours. PMID:20530435

Muftuler, F Z Biber; Unak, P; Yolcular, S; Kilcar, A Yurt; Ichedef, C; Enginar, H; Sakarya, S

2010-04-01

251

Morphine and morphine-glucuronide concentrations in plasma and CSF during long-term administration of oral morphine.  

PubMed Central

Concentrations of morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) were measured by h.p.l.c. in plasma and cerebrospinal fluid (CSF) samples from 16 patients with cancer receiving oral (controlled-release) morphine. There was a close correlation between plasma and CSF morphine concentrations (r = 0.94, P = 0.0001) and both correlated with drug dosage (r = 0.61, P = 0.013 and r = 0.74, P = 0.0001, respectively). M3G and M6G in plasma and CSF were correlated (r = 0.81 and r = 0.82, both P = 0.0001). No relationship was apparent between M plus M6G concentrations in the CSF and pain scores.

van Dongen, R T; Crul, B J; Koopman-Kimenai, P M; Vree, T B

1994-01-01

252

Drug and xenobiotic glucuronidation catalysed by cloned human liver UDP-Glucuronosyltransferases stably expressed in tissue culture cell lines.  

PubMed

Two human UDP-Glucuronosyltransferase (UGT) cDNA clones were stably integrated into V79 chinese hamster fibroblast cells and the functional enzymes were expressed in this heterologous environment. More than 100 drugs and xenobiotics were used as substrates for glucuronidation, catalysed by the cloned UGTs to determine the chemical structures accepted as substrates. UGT HP1 exhibited a limited specificity for planar phenolic compounds, whereas UGT HP4 was more promiscuous in acceptance of non-planar phenols, anthraquinones, flavones, aliphatic alcohols, aromatic carboxylic acids, steroids and many drugs of varied structure. These conclusions are illustrated here by using a series of alkyl- and halophenols. This work indicates the considerable potential value in use of these recombinant cell lines to study human drug glucuronidation. PMID:8236271

Wooster, R; Ebner, T; Sutherland, L; Clarke, D; Burchell, B

1993-10-01

253

Simple measurement of gluconeogenesis by direct2H NMR analysis of menthol glucuronide enrichment from2H2O  

Microsoft Academic Search

The contribution of gluconeogenesis to fasting glucose produc- tion was determined by a simple measurement of urinary men- thol glucuronide (MG) 2H enrichment from 2H2O. Following in- gestion of 2H2O (0.5% body water) during an overnight fast and a pharmacological dose (400 mg) of a commercial peppermint oil preparation the next morning, 364 mol MG was quantita- tively recovered from

Angela Ribeiro; M. Madalena Caldeira; Manuela Carvalheiro; Margarida Bastos; Carla Baptista; Ana Fagulha; Luisa Barros; Cristina Barosa; John G. Jones

2005-01-01

254

Identification of brain-targeted bioactive dietary quercetin-3-O-glucuronide as a novel intervention for Alzheimer's disease.  

PubMed

Epidemiological and preclinical studies indicate that polyphenol intake from moderate consumption of red wines may lower the relative risk for developing Alzheimer's disease (AD) dementia. There is limited information regarding the specific biological activities and cellular and molecular mechanisms by which wine polyphenolic components might modulate AD. We assessed accumulations of polyphenols in the rat brain following oral dosage with a Cabernet Sauvignon red wine and tested brain-targeted polyphenols for potential beneficial AD disease-modifying activities. We identified accumulations of select polyphenolic metabolites in the brain. We demonstrated that, in comparison to vehicle-control treatment, one of the brain-targeted polyphenol metabolites, quercetin-3-O-glucuronide, significantly reduced the generation of ?-amyloid (A?) peptides by primary neuron cultures generated from the Tg2576 AD mouse model. Another brain-targeted metabolite, malvidin-3-O-glucoside, had no detectable effect on A? generation. Moreover, in an in vitro analysis using the photo-induced cross-linking of unmodified proteins (PICUP) technique, we found that quercetin-3-O-glucuronide is also capable of interfering with the initial protein-protein interaction of A?(1-40) and A?(1-42) that is necessary for the formation of neurotoxic oligomeric A? species. Lastly, we found that quercetin-3-O-glucuronide treatment, compared to vehicle-control treatment, significantly improved AD-type deficits in hippocampal formation basal synaptic transmission and long-term potentiation, possibly through mechanisms involving the activation of the c-Jun N-terminal kinases and the mitogen-activated protein kinase signaling pathways. Brain-targeted quercetin-3-O-glucuronide may simultaneously modulate multiple independent AD disease-modifying mechanisms and, as such, may contribute to the benefits of dietary supplementation with red wines as an effective intervention for AD. PMID:23097297

Ho, Lap; Ferruzzi, Mario G; Janle, Elsa M; Wang, Jun; Gong, Bing; Chen, Tzu-Ying; Lobo, Jessica; Cooper, Bruce; Wu, Qing Li; Talcott, Stephen T; Percival, Susan S; Simon, James E; Pasinetti, Giulio Maria

2012-10-24

255

Urinary metabolic profile of 19-norsteroids in humans: glucuronide and sulphate conjugates after oral administration of 19-nor-4-androstenediol.  

PubMed

19-Nor-4-androstenediol (NOL) is a prohormone of nandrolone (ND). Both substances are included in the WADA List of Prohibited Classes of Substances and their administration is determined by the presence of 19-norandrosterone (NA) with the urinary threshold concentration of 2 ng mL(-1). Routine analytical procedures allow the determination of NA excreted free and conjugated with glucuronic acid, but amounts of ND and NOL metabolites are also excreted in the sulphate fraction. The aim of this study is to determine the urinary metabolic profile after oral administration of a nutritional supplement containing NOL. Urine samples were collected up to 96 h following supplement administration and were extracted to obtain separately three metabolic fractions: free, glucuronide and sulphate. Extraction with tert-butyl methyl ether was performed after the hydrolysis steps and trimethylsilyl derivatives were analyzed by gas chromatography/mass spectrometry (GC/MS). After oral administration of NOL, the main metabolites detected were NA and noretiocholanolone (NE) in the glucuronide and sulphate fractions. The relative abundances of each metabolite in each fraction fluctuate with time; a few hours after administration the main metabolite was NA glucuronide whereas in the last sample (4 days after administration) the main metabolite was the NA sulphate and the second was the NE glucuronide. During the studied period almost half of the dose was excreted and the main metabolites were still found in urine after 96 h. Norepiandrosterone and norepietiocholanolone were also detected only in the sulphate fraction. Our results suggest that sulphate metabolites should be taken into consideration in order to increase the retrospectivity in the detection of 19-norsteroids after oral administration. PMID:18763272

Torrado, Susana; Roig, Meritxell; Farré, Magi; Segura, Jordi; Ventura, Rosa

2008-10-01

256

Simultaneous determination of buprenorphine, norbuprenorphine, and buprenorphine–glucuronide in plasma by liquid chromatography–tandem mass spectrometry  

Microsoft Academic Search

For the first time, an LC–MS–MS method has been developed for the simultaneous analysis of buprenorphine (BUP), norbuprenorphine (NBUP), and buprenorphine–glucuronide (BUPG) in plasma. Analytes were isolated from plasma by C18 SPE and separated by gradient RP-LC. Electrospray ionization and MS–MS analyses were carried out using a PE-Sciex API-3000 tandem mass spectrometer. The m\\/z 644?m\\/z 468 transition was monitored for

Aldo Polettini; Marilyn A Huestis

2001-01-01

257

Liquid chromatographic-mass spectrometric analysis of glucuronide-conjugated anabolic steroid metabolites: method validation and interlaboratory comparison  

Microsoft Academic Search

Liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS\\/MS) method for simultaneous and direct detection of 12 glucuronide-conjugated anabolic androgenic steroid (AAS) metabolites in human urine is described. The compounds selected were the main metabolites detected in human urine after dosing of the most widely abused AAS in sports, e.g. methandienone, methenolone, methyltestosterone, nandrolone and testosterone, and certain deuterium-labeled analogs of

Laura Hintikka; Tiia Kuuranne; Antti Leinonen; Mario Thevis; W. Schanzer; John Halket; David Cowan; Joachim Grosse; Peter Hemmersbach; Michel W. F. Nielen; Risto Kostiainen

2008-01-01

258

Investigation of in vitro efficiency of magnetic nanoparticle-conjugated 125 I-uracil glucuronides in adenocarcinoma cells  

Microsoft Academic Search

Modification of the magnetic properties of a drug can be used to direct the drug to the desired site, enhancing its therapeutic\\u000a effectiveness and reducing side effects. In this study, surface-modified magnetic nanoparticles were immobilized with uracil\\u000a glucuronide derivatives and then labeled with I-125. The morphology, structure, and composition of the magnetic particles\\u000a were examined by TEM, SEM, VSM, and

E. Ilker Medine; Perihan Ünak; Serhan Sakarya; Feriha Özkaya

259

Enzymatic synthesis of 125\\/131I labeled 8-hydroxyquinoline glucuronide and in vitro\\/ in vivo evaluation of biological influence  

Microsoft Academic Search

8-Hydroxyquinoline (8-OHQ) is a long-known molecule which due to its metal-complexation ability is frequently used for analysis. It is also called oxine. Oxine and derivatives have been investigated to process antitumor and antimicrobial activities. 8-Hydroxyquinolyl-glucuronide (8-OHQ-Glu) was enzymatically synthesized using microsome preparates separated from Hutu-80 cells, labeled with 125I to perform a radionuclide labeled prodrug and investigated of its biological

Reyhan Ye?ila?aç; Perihan Ünak; E. ?lker Medine; Çi?dem A. ?çhedef; Turkan Ertay; F. Z. Biber Müftüler

2011-01-01

260

Production of ethyl alcohol from bananas  

SciTech Connect

The production of ethyl alcohol from waste bananas presents many special problems. During cooking, matting of the latex fibers from the banana peel recongeal when cooled and left untreated. This problem has been addressed by Alfaro by the use of CaC1/sub 2/. Separation of solids prior to distillation of the mashes in an economical fashion and use of the by product are also of concern to banana processors.

Jones, R.L.; Towns, T.

1983-12-01

261

Methyl ethyl ketone extraction of Tc species  

Microsoft Academic Search

Methyl ethyl ketone extraction of technetium species from aqueous solutions of neutron irradiated ammonium molybdate crystals was studied; the two species extracted were separated by high voltage paper electrophoresis. The one was the99mTcO\\u000a4\\u000a–\\u000a ion and the other, a99mTc non-charged immobile species, probably TcO2.aq, which concentrated at the point of application on the electrophoresis paper strip.

S. Bulbulian

1984-01-01

262

Ethyl pyruvate improves survival in awake hemorrhage  

Microsoft Academic Search

Classical experimental models of hemorrhage are characterized by the use of anesthetics that may interfere with the typical\\u000a immune responses and pathology of hemorrhage\\/resuscitation. Thus, therapeutic strategies successful in anesthetized animals\\u000a might not be beneficial in clinical trials. In this study, we analyzed whether ethyl pyruvate could provide therapeutic benefits\\u000a during resuscitation in awake (unanesthetized) hemorrhage. Our results indicate that

Bolin Cai; Michael Brunner; Haichao Wang; Ping Wang; Edwin A. Deitch; Luis Ulloa

2009-01-01

263

Is the Kidney a Major Storage Site for Thyroxine as Thyroxine Glucuronide?  

PubMed Central

Background Previous studies have shown that thyroxine (T4) is stored as T4 glucuronide (T4G) in the kidney, and that 24 hours after administration of [125I]T4 to mice, 17% of the radioactivity was present in the kidneys, whereas only 4% was found in the liver. The present study was carried out to determine the relative amounts of conjugated and unconjugated T4 and 3,5,3?-triiodothyronine (T3) in the kidney and liver, and whether the conjugated hormones are extracted from tissues using our established extraction protocols, and detected in our radioimmunoassays (RIAs) for T4 and T3. Methods Mice were injected with 10??Ci [125I]T4 or [125I]T3 and 24 hours later, the labeled compounds present in serum, kidney, liver, and urine were extracted and analyzed by paper chromatography before and after treatment with ?-glucuronidase. In addition, the amounts of endogenous T4 and T3 in extracts of mouse kidney and liver were measured by RIA before and after treatment with ?-glucuronidase. Results After [125I]T4, more than 95% of the total kidney and liver radioactivity was extracted, and in the kidney, almost all of it was present in a conjugated form, mostly as T4G. The liver also contained T4G, but none was present in serum or urine. T3 glucuronide (T3G) was also found in the kidney and liver after the administration of [125I]T3. Analysis by RIA of the endogenous T4 content in extracts of kidney before and after hydrolysis by ?-glucuronidase revealed that a substantial fraction of the T4 in both tissues was present as T4G, and the T4G was not detected in the RIA. Furthermore, the combined T4+T4G content in the kidney expressed per gram of tissue was significantly higher than that in the liver or serum. In contrast, the kidney content of T3+T3G was very low compared with that of T4+T4G. Conclusions In summary, we have shown that the kidney stores a significant amount of T4 as T4G. Since T4G deconjugation can occur rapidly in the kidney, it is possible that this tissue participates in maintaining extrathyroidal serum T4 homeostasis.

Buitendijk, Maarten

2012-01-01

264

Respiratory depression following morphine and morphine-6-glucuronide in normal subjects.  

PubMed Central

1. Morphine 6-glucuronide (M6G) is a metabolite of morphine with analgesic activity. A double-blind, randomised comparison of the effects of morphine and M6G on respiratory function was carried out in 10 normal subjects after i.v. morphine (10 mg 70 kg-1) or M6G (1, 3.3 and 5 mg 70 kg-1). Analgesic potency was also assessed using an ischaemic pain test and other toxic effects were monitored. 2. Following morphine there was a significant increase in arterial PCO2, as measured by blood gases 45 min post dose (0.54 +/- 0.24 (s.d.) kPa, P < 0.001), and in transcutaneous PCO2 from 15 min post dose until the end of the study period (4 h), whereas blood gas and transcutaneous PCO2 were unchanged after M6G at 1.0, 3.3 and 5.0 mg 70 kg-1. This increased PCO2 following morphine was associated with an increase in expired CO2 concentration (FECO2) (0.20 +/- 0.14% expired air at 15 min post dose, P = 0.002), compared with small but significant reductions in FECO2 following morphine 6-glucuronide (-0.15 +/- 0.17% at 1 mg 70 kg-1 P = 0.030, -0.14 +/- 0.15% at 3.3 mg 70 kg-1 P = 0.017, -0.18 +/- 0.11% at 5 mg 70 kg-1 P = 0.024). Maximum transcutaneous PCO2 was significantly increased after morphine (0.63 +/- 0.28 kPa P = 0.009), but was not changed after M6G at 1 mg (0.10 +/- 0.34 kPa P = 0.11) 3.3 mg (0.06 +/- 0.37 kPa P = 0.34) or 5 mg (0.26 +/- 0.07 kPa P = 0.10).(ABSTRACT TRUNCATED AT 250 WORDS)

Thompson, P I; Joel, S P; John, L; Wedzicha, J A; Maclean, M; Slevin, M L

1995-01-01

265

Impact of hair-care products on FAEE hair concentrations in substance abuse monitoring.  

PubMed

Previous studies have indicated that the use of high-ethanol-content (>65%) hair-care products may elevate fatty acid ethyl ester (FAEE) concentrations in hair. In this case series, nine individuals were identified by FAEE analysis to be chronic alcohol abusers in the context of child-welfare substance abuse monitoring. Based on patient claims of moderate or no alcohol consumption, the presence of ethanol in the patients' hair-care regimens was investigated. Samples were additionally tested for the presence of ethyl glucuronide (EtG). From a total of nine patients, 12 hair samples were submitted for analysis. Patient histories were obtained as well as Material Safety Data Sheets (MSDS) listing hair-care product ethanol content. Hair samples were pre-washed to remove external contamination and analyzed for FAEE and EtG by GC-MS. According to the Society of Hair Testing consensus guidelines, FAEE levels exceeding 0.50 ng/mg and/or EtG levels exceeding 30 pg/mg indicate chronic excessive alcohol consumption. Upon initial analysis, the nine samples exhibited positive FAEE findings ranging from 0.496 to 4.984 ng/mg. MSDS review revealed the presence of ethanol from 10% to 95% by volume in at least one hair-care product used by each individual. Results of the EtG analysis ranged from 1.9 to 23.5 pg/mg. These findings indicate that regular use of products with ethanol content as low as 10% can impact FAEE results. EtG analysis should be used to confirm FAEE findings and appears to be unaffected by hair-care products, likely due to alternative mechanisms of incorporation. PMID:21301822

Gareri, Joey; Appenzeller, Brice; Walasek, Paula; Koren, Gideon

2011-02-08

266

Stereoselective glucuronidation of ornidazole in humans: predominant contribution of UDP-glucuronosyltransferases 1A9 and 2B7.  

PubMed

Ornidazole [R,S-1-chloro-3-(2-methyl-5-nitro-1H-imidazol-1-yl)propan-2-ol] is a chiral 5-nitroimidazole class antimicrobial agent. This study aimed to investigate the principal metabolic pathway of ornidazole in humans and identify the major enzymes involved. A total of 19 metabolites were identified in human urine collected from patients with hepatobiliary diseases after an intravenous drip infusion of 500 mg of racemic ornidazole. Stereoselective glucuronidation, followed by renal excretion, was the principal metabolic pathway of ornidazole in humans, accounting for 37.3% of the administered dose. Screening assays with 12 available human recombinant UDP-glucuronosyltransferases (UGTs) demonstrated that UGT1A9 was the predominant UGT isoform involved in R-ornidazole glucuronidation, whereas S-ornidazole glucuronidation was almost exclusively catalyzed by UGT2B7. Chemical inhibition study with niflumic acid and flurbiprofen supported these findings. Enzyme kinetic parameters were then determined in human liver microsomes (HLMs), human kidney microsomes (HKMs), UGT1A9, and 2B7. The K(m) values for UGT1A9 (15.6 ± 1.6 mM for R-ornidazole) and 2B7 (3.8 ± 0.9 mM for S-ornidazole) were quite similar to those determined in HLMs and HKMs (20.1 ± 1.4 and 17.7 ± 4.0 mM for R-ornidazole; 6.6 ± 1.3 and 3.2 ± 0.4 mM for S-ornidazole). The in vitro intrinsic clearance (CL(int)) ratios of S- to R-ornidazole were approximately 4.3 in HLMs and 6.5 in HKMs, respectively. The hepatic and renal clearances were estimated based on the well-stirred model. Overall, stereoselective glucuronidation was the principal metabolic pathway of ornidazole in humans. Furthermore, UGT1A9 and 2B7 were the predominant UGT isoforms responsible for R- and S-ornidazole glucuronidation in humans, respectively. PMID:23571427

Du, Jiangbo; You, Tiangeng; Chen, Xiaoyan; Zhong, Dafang

2013-04-09

267

Effects of herbal supplements on drug glucuronidation. Review of clinical, animal, and in vitro studies.  

PubMed

The use of herbal supplements has increased steadily over the last decade. Recent surveys show that many people who take herbal supplements also take prescription and nonprescription drugs, increasing the risk for potential herb-drug interactions. While cytochrome P450-mediated herb-drug interactions have been extensively characterized, the effects of herbal extracts and constituents on UDP-glucuronosyl transferase (UGT) enzymes have not been adequately studied. Thus, the purpose of this review is to evaluate current evidence on the glucuronidation of phytochemicals and the potential for UGT-mediated herb-drug interactions with the top-selling herbal supplements in the United States and Europe. IN VITRO and animal studies indicate that cranberry, GINKGO BILOBA, grape seed, green tea, hawthorn, milk thistle, noni, soy, St. John's wort, and valerian are rich in phytochemicals that can modulate UGT enzymes. However, the IN VIVO consequences of these interactions are not well understood. Only three clinical studies have investigated the effects of herbal supplements on drugs cleared primarily through UGT enzymes. Evidence on the potential for commonly used herbal supplements to modulate UGT-mediated drug metabolism is summarized. Moreover, the need for further research to determine the clinical consequences of the described interactions is highlighted. PMID:21049395

Mohamed, Mohamed-Eslam F; Frye, Reginald F

2010-11-03

268

Chemical and Enzyme-Assisted Syntheses of Norbuprenorphine-3-?-D-Glucuronide  

PubMed Central

Norbuprenorphine-3-?-D-glucuronide (nBPN-3-?-D-G, 1) is a major phase II metabolite of buprenorphine, a pharmaceutical used for the treatment of opioid addiction. The pharmacological activity of compound 1 is not clear because investigations have been limited by the lack of chemically pure, well characterized 1 in sufficient quantities for in vitro and in vivo experiments. This work describes two concise, new methods of synthesis of 1, a chemical and an enzyme-assisted synthesis. The chemical synthesis used a strategy based on a combination of Koenig-Knorr coupling and amino-silyl protection. The enzyme-assisted synthesis used dog liver to convert substrate norbuprenorphine (nBPN, 2) to 1. Both methods provided 1, characterized by 1H NMR and tandem mass spectrometry, with purity >96%. The fractional yield of the enzyme-assisted synthesis was greater than that of the chemical synthesis (67% vs 5.3%), but due to larger reaction volumes, the chemical synthesis afforded greater amounts of total 1.

Fan, Jinda; Brown, Sarah M.; Tu, Zhude; Kharasch, Evan D.

2011-01-01

269

A high throughput assay for the glucuronidation of 7-hydroxy-4-trifluoromethylcoumarin by recombinant human UDP-glucuronosyltransferases and liver microsomes.  

PubMed

Abstract 1.? UDP-glucuronosyltransferases (UGTs) are versatile and important conjugation enzymes in the metabolism of drugs and other xenobiotics. 2.? We have developed a convenient quantitative multi-well plate assay to measure the glucuronidation rate of 7-hydroxy-4-trifluoromethylcoumarin (HFC) for several UGTs. 3.? We have used this method to screen 11 recombinant human UGTs for HFC glucuronidation activity and studied the reaction kinetics with the most active enzymes. We have also examined the HFC glucuronidation activity of liver microsomes from human, pig, rabbit and rat. 4.? At a substrate concentration of 20?µM, the most active HFC glucuronidation catalysts were UGT1A10 followed by UGT1A6 >UGT1A7 >UGT2A1, whereas at 300?µM UGT1A6 was about 10 times better catalyst than the other recombinant UGTs. The activities of UGTs 1A3, 1A8, 1A9, 2B4 and 2B7 were low, whereas UGT1A1 and UGT2B17 exhibited no HFC glucuronidation activity. UGT1A6 exhibited a significantly higher Vmax and Km values toward both HFC and UDP-glucuronic acid than the other UGTs. 5.? Human, pig and rabbit, but not rat liver microsomes, catalyzed HFC glucuronidation at high rates. 6.? This new method is particularly suitable for fast activity screenings of UGTs 1A6, 1A7, 1A10 and 2A1 and HFC glucuronidation activity determination from various samples. PMID:23551063

Rahikainen, Tuomas; Häkkinen, Merja R; Finel, Moshe; Pasanen, Markku; Juvonen, Risto O

2013-04-03

270

Pulse radiolysis of aqueous solutions of ethyl acrylate and hydroxy ethyl acrylate  

NASA Astrophysics Data System (ADS)

Ethyl- and hydroxy ethyl acrylate show high reactivities with hydrated electron and hydroxyl radical intermediates of water radiolysis. The electron adduct reversibly protonate with pK values of 5.7 and 7.3. The adducts may take part in irreversible protonation at the ? carbon atom forming ?-carboxyl alkyl radicals. Same type of radical forms in reaction of acrylates with OH: at low concentration the adduct mainly disappear in self termination reactions. Above 5 mmol dm-1 the signals showed the startup of oligomerization.

Safrany, A.; Biro, A.; Wojnarovits, L.

1993-10-01

271

Pallidol hexa-acetate ethyl acetate monosolvate  

PubMed Central

The entire mol­ecule of pallidol hexa­acetate {systematic name: (±)-(4bR,5R,9bR,10R)-5,10-bis­[4-(acet­yloxy)phen­yl]-4b,5,9b,10-tetra­hydro­indeno­[2,1-a]indene-1,3,6,8-tetrayl tetra­acetate} is completed by the application of twofold rotational symmetry in the title ethyl acetate solvate, C40H34O12·C4H8O2. The ethyl acetate mol­ecule was highly disordered and was treated with the SQUEEZE routine [Spek (2009 ?). Acta Cryst. D65, 148–155]; the crystallographic data take into account the presence of the solvent. In pallidol hexa­acetate, the dihedral angle between the fused five-membered rings (r.m.s. deviation = 0.100?Å) is 54.73?(6)°, indicating a significant fold in the mol­ecule. Significant twists between residues are also evident as seen in the dihedral angle of 80.70?(5)° between the five-membered ring and the pendent benzene ring to which it is attached. Similarly, the acetate residues are twisted with respect to the benzene ring to which they are attached [C—O(carb­oxy)—C—C torsion angles = ?70.24?(14), ?114.43?(10) and ?72.54?(13)°]. In the crystal, a three-dimensional architecture is sustained by C—H?O inter­actions which encompass channels in which the disordered ethyl acetate mol­ecules reside.

Mao, Qinyong; Taylor, Dennis K.; Ng, Seik Weng; Tiekink, Edward R. T.

2013-01-01

272

Nonenzymatic hydrolysis of creatine ethyl ester  

Microsoft Academic Search

The rate of the non-enzymatic hydrolysis of creatine ethyl ester (CEE) was studied at 37°C over the pH range of 1.6–7.0 using 1H NMR. The ester can be present in solution in three forms: the unprotonated form (CEE), the monoprotonated form (HCEE+), and the diprotonated form (H2CEE2+). The values of pKa1 and pKa2 of H2CEE2+ were found to be 2.30

Nicholas S. Katseres; David W. Reading; Luay Shayya; John C. DiCesare; Gordon H. Purser

2009-01-01

273

Glucuronidation of the oxidative cytochrome P450-mediated phenolic metabolites of the endocrine disruptor pesticide: methoxychlor by human hepatic UDP-glucuronosyl transferases.  

PubMed

Methoxychlor, a currently used pesticide, is a proestrogen exhibiting estrogenic activity in mammals in vivo. Methoxychlor undergoes oxidative metabolism by cytochromes P450, yielding 1,1,1-trichloro-2-(4-hydroxyphenyl)-2-(4-methoxyphenyl)ethane (mono-OH-M) and 1,1,1-trichloro-2,2-bis(4-hydroxyphenyl)ethane (bis-OH-M) as main metabolites. Since humans may be exposed to these estrogenic metabolites, which are potential substrates of UDP-glucuronosyltransferases (UGTs), their glucuronide conjugation was investigated with human liver preparations and individual UGTs. Incubation of both mono-OH-M and bis-OH-M with human liver microsomes formed monoglucuronides. The structures of the glucuronides were identified by liquid chromatography/tandem mass spectometry. Examination of cDNA-expressed recombinant human hepatic UGTs revealed that several catalyze glucuronidation of both compounds. Among the cDNA-expressed UGT1A enzymes, UGT1A9 seemed to be the main catalyst of formation of mono-OH-M-glucuronide, whereas UGT1A3 seemed to be the most active in bis-OH-M-glucuronide formation. Furthermore, the chiral selectivity of mono-OH-M glucuronidation was examined. The results of the incubation of single enantiomers generally agreed with the chiral analyses of mono-OH-M derived from the glucuronidase digestion of the glucuronides of the racemic mono-OH-M. There was a relatively slight but consistent enantioselective preference of individual UGT1A1, UGT1A3, UGT1A9, and UGT2B15 enzymes for glucuronidation of the S- over the R-mono-OH-M, whereas in human liver microsomes differences were observed among donors in generating the respective R/S-mono-OH-M ratio. Since it was previously shown that human liver microsomes demethylate methoxychlor mainly into S-mono-OH-M, the observation that UGT1A isoforms preferentially glucuronidate the S-mono-OH-M suggests a suitable mechanism for eliminating this major enantiomer. This enantiomeric preference, however, is not extended to all samples of human liver microsomes that we tested. PMID:15205390

Hazai, Eszter; Gagne, Peter V; Kupfer, David

2004-07-01

274

Ethyl carbamate in foods and beverages: a review  

Microsoft Academic Search

Food and beverages contain many toxic chemicals that raise health concerns. Ethyl carbamate (EC) or urethane is the ethyl\\u000a ester of carbamic acid. It occurs at low level, from ng\\/L to mg\\/L, in many fermented foods and beverages. Ethyl carbamate\\u000a is genotoxic and carcinogenic for a number of species such as mice, rats, hamsters and monkeys. It has been classified

J. V. Weber; V. I. Sharypov

2009-01-01

275

Hydroxycinnamic acid ethyl esters as precursors to ethylphenols in wine.  

PubMed

A method for determining ethyl coumarate and ethyl ferulate in wine using GC-MS with deuterium-labeled analogues has been developed and used to measure the evolution of these two esters during the production of two commercial monovarietal red wines, cv. Grenache and Shiraz. During fermentation, the concentration of ethyl coumarate rose from low levels to 0.4 mg/L in Grenache and 1.6 mg/L in Shiraz wines. These concentrations then increased further during barrel aging to 1.4 and 3.6 mg/L, respectively. The concentration of ethyl ferulate was much lower, reaching a maximum of only 0.09 mg/L. Conversion of ethyl coumarate and ethyl ferulate to their corresponding ethylphenols was observed during fermentations of a synthetic medium with two strains of Dekkera bruxellensis (AWRI 1499 and AWRI 1608), while a third (strain AWRI 1613) produced no ethylphenols at all from these precursors. Strains AWRI 1499 and 1608 produced 4-ethylphenol from ethyl coumarate in 68% and 57% yields, respectively. The corresponding yields of 4-ethylguaiacol from ethyl ferulate were much lower, 7% and 3%. Monitoring of ethyl coumarate and ethyl ferulate concentration during the Dekkera fermentations showed that the selectivity for ethylphenol production according to yeast strain and the precursor was principally a result of variation in esterase activity. Consequently, ethyl coumarate can be considered to be a significant precursor to 4-ethylphenol in wines affected by these two strains of Brettanomyces/Dekkera yeast, while ethyl ferulate is not an important precursor to 4-ethylguaiacol. PMID:22324721

Hixson, Josh L; Sleep, Nicola R; Capone, Dimitra L; Elsey, Gordon M; Curtin, Christopher D; Sefton, Mark A; Taylor, Dennis K

2012-02-23

276

A Simple and Efficient Synthesis of Ethyl and Methyl Glyoxylate  

Microsoft Academic Search

Ethyl and methyl glyoxylate are both prepared in high yields from an exchange reaction between the appropriate alkyl dialkoxyacetate and glyoxylic acid, followed by reaction with phosphorus pentoxide.

James M. Hook

1984-01-01

277

Adiabatic and nonadiabatic dissociation of ethyl radical  

NASA Astrophysics Data System (ADS)

Direct ab initio molecular dynamics using the trajectory surface hopping method with Tully's fewest switches simulates the photodissociation dynamics of ethyl radical, C2H5, following electronic excitation to the A~-state. Nonadiabatic dissociation dominates and produces ground state ethylene and fast hydrogen atoms with an anisotropic angular distribution. Surface hopping also generates hot ground state ethyl radicals followed ultimately by unimolecular dissociation to C2H4+H. The calculated excited state lifetime and the product recoil energy distribution obtained from an ensemble of trajectories are consistent with previous experiments and suggest that a strictly nonadiabatic mechanism can account for nonradiative decay. This process is in competition with adiabatic dissociation producing electronically excited state ethylene and H, a dissociation channel that has not yet been experimentally observed. The branching ratio between adiabatic and nonadiabatic dissociation pathways depends sensitively on the quality of the potential energy surfaces. At the multireference configuration interaction with singles and doubles level of theory, 15% of all trajectories dissociate adiabatically.

Hostettler, Jonas M.; Bach, Andreas; Chen, Peter

2009-01-01

278

Morphine-6-glucuronide: analgesic effects and receptor binding profile in rats  

SciTech Connect

The antinociceptive effects of morphine-6-glucuronide (M6G) were examined in two animal models of pain, the tail immersion test (reflex withdrawal to noxious heat) and the formalin test (behavioral response to minor tissue injury). In the tail immersion test, M6G produced and increase in withdrawal latency that rose rapidly between 0.01 and 0.025 ug ICV or 1 and 2 mg/kg SC. A further increase occurred at doses greater than 0.2 ug ICV or 4 mg/kg SC and was associated with marked catelepsy and cyanosis. Naloxone, 0.1 mg/kg SC, shifted the lower component of the dose-effect relation by a factor of 24. In the formalin test, 0.01 ug M6G ICV produced hyperalgesia, while between 0.05 and 0.2 ug ICV, antinociception increased rapidly without toxicity. The dose effect relations for hyperalgesia and antinociception were shifted to the right by factors of 20- and 3-fold, respectively. By comparison, ICV morphine was 60 (formalin test) to 145-200 (tail immersion test) times less potent than M6G. At sub-nanomolar concentrations, M6G enhanced the binding of (/sup 3/H)-etorphine, (/sup 3/H)-dihydromorphine and (/sup 3/H)-naloxone to rat brain membrane receptors by 20-40%. At higher concentrations, M6G displaced each ligand from binding sites, with K/sub i/ values of about 30 nM, as compared to morphine K/sub i/ values of about 3 nM.

Abbott, F.V.; Palmour, R.M.

1988-01-01

279

Investigation of Therapeutic Efficiency of Bleomycin and Bleomycin-Glucuronide Labeled with (131)I on the Cancer Cell Lines.  

PubMed

Abstract The aim of this study is to determine the incorporations of radiolabeled bleomycin ((131)I-BLM) and bleomycin-glucuronide ((131)I-BLMGLU) on PC-3 (human prostate carcinoma cell line), Caco-2 (human colon adenocarcinoma cell line), Hutu-80 (Human Duodenum adenocarcinoma cell line), and A549 (Human lung adenocarcinoma epithelial cell line) cancerous cell lines. For this purpose, BLM and BLMGLU enyzmatically synthesized were labeled with (131)I, quality control studies were done and the incorporation yields of (131)I-BLM and (131)I-BLMGLU on these cell lines were measured. Quality-control studies showed that the radiolabeling yields were obtained as 95% and 90% for (131)I-BLM and (131)I-BLMGLU, respectively. Also, as a result of the cell culture studies, it was found that (131)I-BLM and (131)I-BLMGLU had higher incorporation on PC-3 cells than that of other cell lines. In addition to this, it was reported that the incorporation yield of (131)I-BLMGLU was higher than that (131)I-BLM. At the end of the study, cytotoxicities of BLM and BLMGLU on PC-3 cancerous cell line were inspected and fluorescent images of BLM and BLMGLU were taken on PC-3 cells by using fluorescein isothiocyanate. In conclusion, cell culture studies demonstrated that the incorporation values of (131)I-BLMGLU on the four cell lines were about five to six times higher than (131)I-BLM. Radiolabeled glucuronide derivatives can be used in cancer therapy and tumor imaging, depending on the properties of radioiodine for the ?-glucuronidase-rich tissues because glucuronidation leads to rapid and higher incorporation on adenocarcinoma cells. PMID:23350895

Ediz, Melis; Avc?ba??, U?ur; Unak, Perihan; Müftüler, Fazilet Zümrüt Biber; Medine, Emin ?lker; Yurt K?lçar, Ayfer; Demiro?lu, Hasan; Gümü?er, Fikriye Gül; Sakarya, Serhan

2013-01-25

280

Direct quantification of cannabinoids and cannabinoid glucuronides in whole blood by liquid chromatography–tandem mass spectrometry  

Microsoft Academic Search

The first method for quantifying cannabinoids and cannabinoid glucuronides in whole blood by liquid chromatography–tandem\\u000a mass spectrometry (LC–MS\\/MS) was developed and validated. Solid-phase extraction followed protein precipitation with acetonitrile.\\u000a High-performance liquid chromatography separation was achieved in 16 min via gradient elution. Electrospray ionization was\\u000a utilized for cannabinoid detection; both positive (?9-tetrahydrocannabinol [THC] and cannabinol [CBN]) and negative (11-hydroxy-THC [11-OH-THC], 11-nor-9-carboxy-THC [THCCOOH],

David M. Schwope; Karl B. Scheidweiler; Marilyn A. Huestis

281

Nonenzymatic cyclization of creatine ethyl ester to creatinine  

Microsoft Academic Search

Creatine ethyl ester was incubated at 37°C in both water and phosphate-buffered saline and the diagnostic methylene resonances in the 1H NMR spectrum were used to identify the resultant products. It was found that mild aqueous conditions result in the cyclization of creatine ethyl ester to provide inactive creatinine as the exclusive product, and this transformation becomes nearly instantaneous as

Matthew W. Giese; Carl S. Lecher

2009-01-01

282

Cognitive effects of creatine ethyl ester supplementation.  

PubMed

Supplementation with creatine-based substances as a means of enhancing athletic performance has become widespread. Until recently, however, the effects of creatine supplementation on cognitive performance has been given little attention. This study used a new form of creatine--creatine ethyl ester--to investigate whether supplementation would improve performance in five cognitive tasks, using a double-blind, placebo-controlled study. Creatine dosing led to an improvement over the placebo condition on several measures. Although creatine seems to facilitate cognition on some tasks, these results require replication using objective measures of compliance. The improvement is discussed in the context of research examining the influence of brain energy capacity on cognitive performance. PMID:19773644

Ling, Jonathan; Kritikos, Minos; Tiplady, Brian

2009-12-01

283

Enhanced ethyl butyrate production using immobilized lipase.  

PubMed

Abstract In this study, the production of ethyl butyrate was investigated by using immobilized lipase enzyme in shake flasks. In order to determine optimum conditions for the production, response surface methodology was used. The model indicated the optimum conditions for maximum conversion (9.1%) at the 0.31 M substrate concentration, acid- alcohol molar ratio of 0.49, immobilized enzyme 25% (w/v) at 35°C, for 3 hours which were in good agreement with the experimental value. At the end of the 55 hours conversion was obtained as 61.3%. When Na2HPO4 was used in reaction medium conversion increased to 90.3% for 55 hours. PMID:23305408

Ate?, Selma; Türk, Burcu; Bayraktar, Emine; Güvenç, Afife

2013-01-10

284

A morphogenetic regulatory role for ethyl alcohol in Candida albicans.  

PubMed

Regulation of morphogenesis through the production of chemical signalling molecules such as isoamyl alcohol, 2-phenylethyl alcohol, 1-dodecanol, E-nerolidol and farnesol is reported in Candida albicans. The present study focuses on the effect of ethyl alcohol on C. albicans dimorphism and biofilm development. Ethyl alcohol inhibited germ tube formation induced by the four standard inducers in a concentration-dependent manner. The germ tube inhibitory concentration (4%) did not have any effect on the growth and viability of C. albicans cells. Ethyl alcohol also inhibited the elongation of germ tubes. Four percentage of ethyl alcohol significantly inhibited biofilm development on polystyrene and silicone surfaces. We suggest a potential morphogenetic regulatory role for ethyl alcohol, which may influence dissemination, virulence and establishment of infection. PMID:21605190

Chauhan, Nitin M; Raut, Jayant S; Karuppayil, S Mohan

2011-05-23

285

Correlation between plasma concentration ratios of SN-38 glucuronide and SN-38 and neutropenia induction in patients with colorectal cancer and wild-type UGT1A1 gene  

PubMed Central

In irinotecan (CPT-11)-based chemotherapy, neutropenia and diarrhea are often induced. In the present study, the clinical significance of the concentration ratios of 7-ethyl-10-hydroxycamptothecin (SN-38) glucuronide (SN-38G) and SN-38 in the plasma in predicting CPT-11-induced neutropenia was examined. A total of 17 patients with colorectal cancer and wild-type UDP-glucuronosyltransferase (UGT)1A1 gene were enrolled and treated with CPT-11 as part of the FOLFIRI regimen [CPT-11 and fluorouracil (5-FU)]. Blood was taken exactly 15 min following a 2-h continuous infusion of CPT-11. Plasma concentrations of SN-38, SN-38G and CPT-11 were determined by a modified high-performance liquid chromatography (HPLC) method. The median, maximum and minimum values of plasma SN-38G/SN-38 ratios were 4.25, 7.09 and 1.03, respectively, indicating that UGT activities are variable among patients with the wild-type UGT1A1 gene. The plasma SN-38G/SN-38 ratios decreased with an increase in the trial numbers of chemotherapy (r=0.741, p=0.000669), suggesting that CPT-11 treatment suppresses UGT activity, and the low plasma SN-38G/SN-38 ratios resulted in the induction of greater neutropenia. However, in this analysis, 2 clearly separated regression lines were observed between plasma SN-38G/SN-38 ratios and neutropenia induction. In conclusion, UGT activity involved in SN-38 metabolism is variable among patients with the wild-type UGT1A1 gene, and each CPT-11 treatment suppresses UGT activity. One-point determination of the plasma SN-38G/SN-38 ratio may provide indications for the prediction of CPT-11-induced neutropenia and adjustment of the optimal dose, although further studies are required.

HIROSE, KOICHI; KOZU, CHIHIRO; YAMASHITA, KOSHIRO; MARUO, EIJI; KITAMURA, MIZUHO; HASEGAWA, JUNICHI; OMODA, KEI; MURAKAMI, TERUO; MAEDA, YORINOBU

2011-01-01

286

Simple measurement of gluconeogenesis by direct 2H NMR analysis of menthol glucuronide enrichment from 2H2O.  

PubMed

The contribution of gluconeogenesis to fasting glucose production was determined by a simple measurement of urinary menthol glucuronide (MG) 2H enrichment from 2H2O. Following ingestion of 2H2O (0.5% body water) during an overnight fast and a pharmacological dose (400 mg) of a commercial peppermint oil preparation the next morning, 364 micromol MG was quantitatively recovered from a 2-h urine collection by ether extraction and a 125 micromol portion was directly analyzed by 2H NMR. The glucuronide 2H-signals were fully resolved and their relative intensities matched those of the monoacetone glucose derivative. The pharmacokinetics and yields of urinary MG after ingestion of 400 mg peppermint oil as either gelatin or enteric-coated capsules 1 h before breakfast were quantified in five healthy subjects. Gelatin capsules yielded 197 +/- 81 micromol of MG from the initial 2-h urine collection while enteric-coated capsules gave 238 +/- 84 micromol MG from the 2- to 4-h urine collection. PMID:16032678

Ribeiro, Angela; Caldeira, M Madalena; Carvalheiro, Manuela; Bastos, Margarida; Baptista, Carla; Fagulha, Ana; Barros, Luisa; Barosa, Cristina; Jones, John G

2005-08-01

287

40 CFR 721.4250 - Hexanoic acid, 2-ethyl-, ethenyl ester.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Hexanoic acid, 2-ethyl-, ethenyl ester. 721...Chemical Substances § 721.4250 Hexanoic acid, 2-ethyl-, ethenyl ester. (a...chemical substance identified as hexanoic acid, 2-ethyl-, ethenyl ester...

2013-07-01

288

40 CFR 180.515 - Carfentrazone-ethyl; tolerances for residues.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Carfentrazone-ethyl; tolerances for residues...Specific Tolerances § 180.515 Carfentrazone-ethyl; tolerances for residues...for combined residues of the herbicide carfentrazone-ethyl...

2009-07-01

289

40 CFR 180.515 - Carfentrazone-ethyl; tolerances for residues.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Carfentrazone-ethyl; tolerances for residues...Specific Tolerances § 180.515 Carfentrazone-ethyl; tolerances for residues...for combined residues of the herbicide carfentrazone-ethyl...

2010-07-01

290

40 CFR 180.515 - Carfentrazone-ethyl; temporary tolerances for residues.  

Code of Federal Regulations, 2010 CFR

...1998-07-01 1998-07-01 false Carfentrazone-ethyl; temporary tolerances for...Specific Tolerances § 180.515 Carfentrazone-ethyl; temporary tolerances for...for combined residues of the herbicide carfentrazone-ethyl...

1998-07-01

291

40 CFR 721.10109 - Hexanoic acid, 2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane.  

Code of Federal Regulations, 2010 CFR

...2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane. 721...2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane. (a...2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane...

2009-07-01

292

40 CFR 721.10109 - Hexanoic acid, 2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane.  

Code of Federal Regulations, 2010 CFR

...2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane. 721...2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane. (a...2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane...

2010-07-01

293

Simultaneous spectrophotometric determination of maltol, ethyl maltol, vanillin and ethyl vanillin in foods by multivariate calibration and artificial neural networks  

Microsoft Academic Search

Maltol (MAL), ethyl maltol (EMA), vanillin (VAN) and ethyl vanillin (EVA) are food additives, and they have well defined UV spectra. However, these overlapped seriously, and it is difficult to determine them individually from their mixtures without a pre-separation. In this paper, chemometric approaches were applied to resolve the overlapping spectra and to determine these compounds simultaneously. The analysis of

Yongnian Ni; Guowen Zhang; Serge Kokot

2005-01-01

294

USE OF ETHYL ALCOHOL TO INCREASE THE YIELD OF THE SZILARD-CHALMERS REACTION WITH ETHYL IODIDE  

Microsoft Academic Search

An alcoholic solution of ethyl iodide was subjected to the thermai ; neutron flux of Reaotor AGN 201 COSTANZA'' in Palermo. The Szilard-Chalmers ; reaction was produced and Ii¹²⁸ was liberated during the irradiation. The ; use of the ethyl alcohol as solvent minimized the retention. The gain in the ; yield seems to be very remarkable. (auth);

C. Cappadona; G. Fierotti; E. Sinagra

1959-01-01

295

Characterization of Dibenzo[a,l ]pyrene-trans-11,12-diol (Dibenzo[def,p]chrysene) Glucuronidation by UDP-glucuronosyltransferases  

PubMed Central

Dibenzo[a,l]pyrene (DB[a,l]P) (dibenzo[def,p]chrysene) is a highly carcinogenic polycyclic aromatic hydrocarbon (PAH) that has been identified in tobacco smoke and is found in our environment due to incomplete combustion of organic matter. Its metabolites are known to form stable DNA adducts in bacteria and mammalian cells, and can lead to tumors in animal models. Glucuronidation of major metabolites of DB[a,l]P by the uridine-5’-diphosphate glucuronosyltransferase (UGT) family of enzymes is an important route of detoxification of this pro-carcinogen. The focus of the current study was to characterize the glucuronidation of the pro-carcinogenic enantiomers DB[a,l]P-(+)-trans-11S,12S–diol and DB[a,l]P-(?)-trans-11R,12R–diol. Glucuronidation assays with HEK293 cell lines over-expressing individual human UGT enzymes demonstrated that UGTs 1A1, 1A4, 1A7, 1A8, 1A9, 1A10, and 2B7 glucuronidated one or both DB[a,l]P-trans-11,12-diol enantiomers. Three glucuronide conjugates were observed in activity assays with UGTs 1A1 and 1A10, while two glucuronides were formed by UGTs 1A7, 1A8, and 1A9, and one glucuronide was made by UGT1A4 and UGT2B7. Enzyme kinetic analysis indicated that UGT1A9 was the most efficient UGT at forming both the (+)-DB[a,l]P-11-Gluc and (?)-DB[a,l]P-11-Gluc products while UGTs 1A1 and 1A10 were the most efficient at forming the (+)-DB[a,l]P-12-Gluc product (as determined by the kcat/KM). Incubations with human liver microsomes showed formation of three diastereomeric glucuronide products: (+)-DB[a,l]P-11-Gluc, (+)-DB[a,l]P-12-Gluc, and (?)-DB[a,l]P-11-Gluc, with an average overall ratio of 31 : 32 : 37 in four liver specimens. Human bronchus and trachea tissue homogenates demonstrated glucuronidation activity against both DB[a,l]P-trans-11,12-diol enantiomers, with both tissues producing the (+)-DB[a,l]P-11-Gluc and (+)-DB[a,l]P-12-Gluc with little or no formation of (?)-DB[a,l]P-11-Gluc. These results indicate that multiple UGTs are involved in the stereospecific glucuronidation of DB[a,l]P-trans-11,12-diol in a pattern consistent with their expression in respiratory tract tissues, and that glucuronidation may be an important first-line detoxification mechanism of DB[a,l]P metabolites.

Olson, Kristine C.; Sun, Dongxiao; Chen, Gang; Sharma, Arun K.; Amin, Shantu; Ropson, Ira J.; Spratt, Thomas E.; Lazarus, Philip

2011-01-01

296

Photodeactivation of ethyl violet: a potential hazard of Sodasorb.  

PubMed

Breathing circuit cannisters containing functional CO2 absorbent are critical to prevent rebreathing CO2 during general anesthesia using closed or semiclosed breathing systems. Ethyl violet is the indicator dye added to Sodasorb to indicate impending exhaustion of the absorbent. A case of CO2 rebreathing due to failure of ethyl violet indicator in exhausted Sodasorb was encountered. Laboratory investigation demonstrated that dye failure could result from photodeactivation caused by fluorescent lights. Using a fixed intensity fluorescent light source and quantitative spectrophotometric analysis, a highly significant dose-response relationship was demonstrated between duration of light exposure and the decrease in ethyl violet concentration. After 24 h of fluorescent light exposure with a received flux density of 46 nwatts/cm2 at 254 nm, the concentration of functional ethyl violet remaining in pulverized Sodasorb was 16% of the baseline value. Furthermore, using multiple light sources of various intensities, the greater the intensity of light, the more rapid the rate of decline of the ethyl violet concentration. It is recommended to minimize the problem by using ultraviolet filters and incorporating additional ethyl violet in Sodasorb. Finally, ethyl violet undergoes temporal deactivation after a Sodasorb container is opened, even if it is stored in the dark. PMID:2105069

Andrews, J J; Johnston, R V; Bee, D E; Arens, J F

1990-01-01

297

Androgen glucuronides analysis by liquid chromatography tandem-mass spectrometry: Could it raise new perspectives in the diagnostic field of hormone-dependent malignancies?  

PubMed

Breast and prostate constitute organs of intense steroidogenic activity. Clinical and epidemiologic data provide strong evidence on the influence of androgens and estrogens on the risk of typical hormone-dependent malignancies, like breast and prostate cancer. Recent studies have focused on the role of androgen metabolites in regulating androgen concentrations in hormone-sensitive tissues. Steroid glucuronidation has been suggested to have a prominent role in controlling the levels and the biological activity of unconjugated androgens. It is well-established that serum levels of androgen glucuronides reflect androgen metabolism in androgen-sensitive tissues. Quantitative analysis of androgen metabolites in blood specimens is the only minimally invasive approach permitting an accurate estimate of the total pool of androgens. During the past years, androgen glucuronides analysis most often involved radioimmunoassays (RIA) or direct immunoassays, both methods bearing serious limitations. However, recent impressive technical advances in mass spectrometry, and particularly in high performance liquid chromatography coupled with mass spectrometry (LC-MS/MS), have overcome these drawbacks enabling the simultaneous, quantitative analysis of multiple steroids even at low concentrations. Blood androgen profiling by LC-MS/MS, a robust and reliable technique of high selectivity, sensitivity, specificity, precision and accuracy emerges as a promising new approach in the study of human pathology. The present review offers a contemporary insight in androgen glucuronides profiling through the application of LC-MS/MS, highlighting new perspectives in the study of steroids and their implication in hormone-dependent malignancies. PMID:24140653

Kalogera, Eleni; Pistos, Constantinos; Provatopoulou, Xeni; Athanaselis, Sotirios; Spiliopoulou, Chara; Gounaris, Antonia

2013-09-27

298

Synthesis and chromatographic evaluation of molecularly imprinted polymers prepared by the substructure approach for the class-selective recognition of glucuronides  

Microsoft Academic Search

Two series of molecularly imprinted polymers (MIPs) for the class-selective recognition of glucuronides have been prepared by using lipophilic substructures of the target analyte as template molecule and potent host monomers against oxyanions, that are expected to establish a strong stoichiometric interaction with the single carboxylic group of the template. The polymers were tested as stationary phases in liquid chromatography

S. Ambrosini; M. Serra; S. Shinde; B. Sellergren; E. De Lorenzi

2011-01-01

299

Enantioselective Reformatsky reaction of ethyl iododifluoroacetate with ketones.  

PubMed

Two approaches have been developed for the enantioselective Reformatsky reaction of ethyl iododifluoroacetate with ketones to form a quaternary carbon centre using (1R,2S)-1-phenyl-2-(1-pyrrolidinyl)-1-propanol as the chiral ligand. Good yields and high enantioselectivities (80-91% ee) were achieved with a range of alkyl aryl ketones in a convenient one-pot protocol using ethyl iododifluoroacetate and diethylzinc to form the difluorinated Reformatsky reagent homogeneously. In the traditional two-step Reformatsky reaction using the preformed Reformatsky reagent generated from ethyl iododifluoroacetate and zinc dust, good yields and good enantioselectivities (75-84% ee) were also obtained. PMID:22421710

Fornalczyk, Michal; Singh, Kuldip; Stuart, Alison M

2012-03-15

300

Non-Steroidal Anti-Inflammatory Drugs Do Not Influence the Urinary Testosterone/Epitestosterone Glucuronide Ratio  

PubMed Central

The UDP Glucuronosyl Transferase (UGT) enzymes are important in the pharmacokinetics, and conjugation, of a variety of drugs including non-steroidal anti-inflammatory drugs (NSAIDs) as well as anabolic androgenic steroids (AAS). Testosterone glucuronidation capacity is strongly associated with a deletion polymorphism in the UGT2B17 gene. As the use of high doses of NSAIDs has been observed in athletes there is a risk for a drug–drug interaction that may influence the doping tests for AAS. In vitro studies show inhibitory potential on UGT2B7, 2B15, and 2B17 enzymes by NSAIDs. The aim of this study was to investigate if concomitant use of NSAIDs and a single dose of testosterone enanthate would affect the excretion rate of testosterone and epitestosterone glucuronide (TG and EG) as well as the T/E ratio, thereby affecting the outcome of the testosterone doping test. The study was designed as an open, randomized, cross-over study with subjects being their own control. The 23 male healthy volunteers, with either two, one or no allele (ins/ins, ins/del, or del/del) of the UGT2B17 gene, received the maximum recommended dose of NSAID (Ibuprofen or Diclofenac) for 6?days. On day three, 500?mg of testosterone enanthate was administered. Spot urine samples were collected for 17?days. After a wash-out period of 4?months the volunteers received 500?mg testosterone enanthate only, with subsequent spot urine collection for 14?days. The glucuronides of testosterone and epitestosterone were quantified. NSAIDs did not affect the excretion of TG or EG before the administration of testosterone. The concomitant use of NSAIDs and testosterone slightly increased the TG excretion while the EG excretion was less suppressed compared to testosterone use only. The effects of the NSAIDs on the TG and EG excretion did not differ between the UGT2B17 genotype groups. In conclusion, the outcome of testosterone doping tests does not seem to be affected by the use of NSAIDs.

Lundmark, Jonas; Garevik, Nina; Thorngren, John-Olof; Garle, Mats; Ekstrom, Lena; Rane, Anders; Schulze, Jenny J.

2013-01-01

301

Kinetic disposition of lorazepam with focus on the glucuronidation capacity, transplacental transfer in parturients and racemization in biological samples.  

PubMed

The present study investigates the kinetic disposition with focus on the racemization, glucuronidation capacity and the transplacental transfer of lorazepam in term parturients during labor. The study was conducted on 10 healthy parturients aged 18-37 years with a gestational age of 36-40.1 weeks, treated with a single oral dose of 2 mg racemic lorazepam 2-9 h before delivery. Maternal venous blood and urine samples were obtained over a 0-48 h interval and the umbilical cord sample was obtained immediately after clamping. Lorazepam enantiomers were determined in plasma and urine samples by LC-MS/MS using a Chiralcel OD-R column. In vitro racemization of lorazepam required the calculation of the pharmacokinetic parameters as isomeric mixtures. The data were fitted to two-compartment model and the pharmacokinetic parameters are reported as means (95% CI): t(1/2a) 3.2h (2.6-3.7 h), K(a) 0.23 h(-1) (0.19-0.28 h(-1)), t(1/2) 10.4h (9.4-11.3h), beta 0.068 h(-1) (0.061-0.075h(-1)), AUC(0-infinity) 175.3(ngh)/ml (145.7-204.8(ngh)/ml), Cl/F 2.6 ml/(minkg) (2.3-2.9 ml/(minkg)), Vd/F178.8l (146.5-211.1l), Fel 0.3% (0.1-0.5%), and Cl(R) 0.010 ml/(minkg) (0.005-0.015 ml/(minkg)). Placental transfer of lorazepam evaluated as the ratio of vein umbilical/maternal vein plasma concentrations, obtained as an isomeric mixture, was 0.73 (0.52-0.94). Pregnancy changes the pharmacokinetics of lorazepam, with an increase in the apparent distribution volume, an increase in apparent oral clearance, and a reduction of elimination half-life. The increase in oral clearance may indicate an increase in glucuronidation capacity, with a possible reduction in the plasma concentrations of drugs depending on glucuronidation capacity as the major metabolic pathway. PMID:16143486

Papini, Olga; da Cunha, Sergio Pereira; da Silva Mathes, Angelo do Carmo; Bertucci, Carlo; Moisés, Elaine Christine Dantas; de Barros Duarte, Luciana; de Carvalho Cavalli, Ricardo; Lanchote, Vera Lucia

2005-09-06

302

Non-steroidal anti-inflammatory drugs do not influence the urinary testosterone/epitestosterone glucuronide ratio.  

PubMed

The UDP Glucuronosyl Transferase (UGT) enzymes are important in the pharmacokinetics, and conjugation, of a variety of drugs including non-steroidal anti-inflammatory drugs (NSAIDs) as well as anabolic androgenic steroids (AAS). Testosterone glucuronidation capacity is strongly associated with a deletion polymorphism in the UGT2B17 gene. As the use of high doses of NSAIDs has been observed in athletes there is a risk for a drug-drug interaction that may influence the doping tests for AAS. In vitro studies show inhibitory potential on UGT2B7, 2B15, and 2B17 enzymes by NSAIDs. The aim of this study was to investigate if concomitant use of NSAIDs and a single dose of testosterone enanthate would affect the excretion rate of testosterone and epitestosterone glucuronide (TG and EG) as well as the T/E ratio, thereby affecting the outcome of the testosterone doping test. The study was designed as an open, randomized, cross-over study with subjects being their own control. The 23 male healthy volunteers, with either two, one or no allele (ins/ins, ins/del, or del/del) of the UGT2B17 gene, received the maximum recommended dose of NSAID (Ibuprofen or Diclofenac) for 6?days. On day three, 500?mg of testosterone enanthate was administered. Spot urine samples were collected for 17?days. After a wash-out period of 4?months the volunteers received 500?mg testosterone enanthate only, with subsequent spot urine collection for 14?days. The glucuronides of testosterone and epitestosterone were quantified. NSAIDs did not affect the excretion of TG or EG before the administration of testosterone. The concomitant use of NSAIDs and testosterone slightly increased the TG excretion while the EG excretion was less suppressed compared to testosterone use only. The effects of the NSAIDs on the TG and EG excretion did not differ between the UGT2B17 genotype groups. In conclusion, the outcome of testosterone doping tests does not seem to be affected by the use of NSAIDs. PMID:23720652

Lundmark, Jonas; Gårevik, Nina; Thörngren, John-Olof; Garle, Mats; Ekström, Lena; Rane, Anders; Schulze, Jenny J

2013-05-16

303

Differences in the pharmacokinetics of peroxisome proliferator-activated receptor agonists in genetically obese Zucker and sprague-dawley rats: implications of decreased glucuronidation in obese Zucker rats.  

PubMed

Genetically obese Zucker rats exhibit symptoms similar to those of obese patients with insulin-resistance or Type II diabetes; therefore, they have been used as a genetic model to study obesity, as well as a pharmacological model for the discovery of new drugs for the treatment of Type II diabetes and hyperlipidemia. In the present study, we compared the pharmacokinetics of two novel peroxisome proliferator-activated receptor (PPAR) agonists, MRL-I [(2R)-7-[3-[2-chloro-4-(4-fluorophenoxy)phenoxy]propoxy]-2-ethyl-3,4-dihydro-2H-benzopyran-2-carboxylic acid] and MRL-II [(2R)-7-[3-[2-chloro-4-(2,2,2-trifluoroethoxy)phenoxy]propoxy]-3,4-dihydro-2-methyl-2H-benzopyran-2-carboxylic acid], in obese Zucker and lean Sprague-Dawley rats following a single intravenous administration. The plasma clearance of both MRL-I and MRL-II was significantly lower in obese Zucker rats (4- and 2-fold, respectively) compared with Sprague-Dawley rats, but without any significant change in the volume of distribution, which resulted in a dramatic increase in the half-life (7- and 3-fold, respectively). The reversible in vitro plasma protein binding of [(14)C]MRL-I and [(14)C]MRL-II was comparable in the two strains, approximately 96% bound. The expression levels of uridine diphosphate-glucuronosyltransferases 1A1, 1A6, 2B1, and CYP2C11 and 3A1 mRNA in liver were lower (30-50%) in Zucker compared with Sprague-Dawley rats, as were the liver glutathione S-transferases (70%), quinone reductase (30%), organic anion-transporting protein 2 (80%), and multidrug resistance-associated protein 2 (Mrp2) (50%) mRNA levels. However, Mrp3 mRNA levels were similar in both strains. Consistent with these observations, the intrinsic clearance (CL(int)), calculated from the V(max)/K(m) of glucuronidation of [(14)C]MRL-I and [(14)C]MRL-II in liver microsomes, was approximately 2-fold lower in obese Zucker rats; the K(m) values were comparable in the two strains for both compounds. In conclusion, differences in the pharmacokinetics of two novel PPAR agonists, both cleared, predominantly, by conjugation, were evident in genetically obese Zucker rats compared with Sprague-Dawley rats. These differences were consistent with changes in the mRNA levels of hepatic drug-metabolizing enzymes and transporters. This information should be considered when comparing pharmacokinetic and efficacious doses in the obese Zucker rats, used as a pharmacological model, with those in Sprague-Dawley rats, which are used widely for drug metabolism and toxicology studies. PMID:15319330

Kim, Mi-Sook; Wang, Sui; Shen, Zhongzhou; Kochansky, Christopher J; Strauss, John R; Franklin, Ronald B; Vincent, Stella H

2004-09-01

304

The glucuronidation of R- and S-lorazepam: human liver microsomal kinetics, UDP-glucuronosyltransferase enzyme selectivity, and inhibition by drugs.  

PubMed

The widely used hypnosedative-anxiolytic agent R,S-lorazepam is cleared predominantly by conjugation with glucuronic acid in humans, but the enantioselective glucuronidation of lorazepam has received little attention. The present study characterized the kinetics of the separate R and S enantiomers of lorazepam by human liver microsomes (HLMs) and by a panel of recombinant human UDP-glucuronosyltransferase (UGT) enzymes. Respective mean K(m) and V(max) values for R- and S-lorazepam glucuronidation by HLM were 29 ± 8.9 and 36 ± 10 µM, and 7.4 ± 1.9 and 10 ± 3.8 pmol/min ? mg. Microsomal intrinsic clearances were not significantly different, suggesting the in vivo clearances of R- and S-lorazepam are likely to be similar. Both R- and S-lorazepam were glucuronidated by UGT2B4, 2B7, and 2B15, whereas R-lorazepam was additionally metabolized by the extrahepatic enzymes UGT1A7 and 1A10. Based on in vitro clearances and consideration of available in vivo and in vitro data, UGT2B15 is likely to play an important role in the glucuronidation of R- and S-lorazepam. However, the possible contribution of other enzymes and the low activities observed in vitro indicate that the lorazepam enantiomers are of limited use as substrate probes for UGT2B15. To identify potential drug-drug interactions, codeine, fluconazole, ketamine, ketoconazole, methadone, morphine, valproic acid, and zidovudine were screened as inhibitors of R- and S-lorazepam glucuronidation by HLM. In vitro-in vivo extrapolation suggested that, of these drugs, only ketoconazole had the potential to inhibit lorazepam clearance to a clinically significant extent. PMID:23554428

Uchaipichat, Verawan; Suthisisang, Chuthamanee; Miners, John O

2013-04-03

305

Synthesis of a series of phenylacetic acid 1-?-O-acyl glucosides and comparison of their acyl migration and hydrolysis kinetics with the corresponding acyl glucuronides.  

PubMed

We report the synthesis of the 1-?-O-acyl glucoside conjugates of phenylacetic acid (PAA), R- and S-?-methyl-PAA and ?,?'-dimethyl-PAA, and measurement of their transacylation and hydrolysis reactivity by NMR methods. These are analogues of acyl glucuronides, the transacylation kinetics of which could be important in adverse drug effects. One aim of this work was to investigate whether, as previously postulated, the free carboxylate group of the acyl glucuronides plays a part in the mechanism of the internal acyl migration. In addition, such acyl glucosides are known to be endogenous biochemicals in their own right and investigation of their acyl migration propensities is novel. Our previously described selective acylation procedure has proved highly successful for 1-?-O-acyl glucuronide synthesis and when subsequently applied to 6-O-trityl glucose, it gave good yields and excellent anomeric selectivity. Mild acidolysis of the O-trityl intermediates gave the desired acyl glucosides in excellent yield with essentially complete ?-selectivity. Measurement of the acyl glucoside transacylation kinetics by (1)H NMR spectroscopy, based simply on the disappearance of the 1-?-isomer in aqueous buffer at pH 7.4, showed marked differences depending on the degree of methyl substitution. Further kinetic modelling of the isomerisation and hydrolysis reactions of the acyl glucosides showed considerable differences in kinetics for the various isomeric reactions. Reactions involving the -CH(2)OH group, presumably via a 6-membered ring ortho-ester intermediate, are facile and the ?-glucoside anomers are significantly more reactive than their ?-counterparts. By comparison with degradation rates for the corresponding acyl glucuronides, it can be inferred that substitution of the carboxylate by -CH(2)OH in the acyl glucosides has a significant effect on acyl migration for those compounds, especially for rapidly transacylating molecules, and that thus the charged glucuronide carboxylate is a factor in the kinetics. PMID:21152488

Iddon, Lisa; Richards, Selena E; Johnson, Caroline H; Harding, John R; Wilson, Ian D; Nicholson, Jeremy K; Lindon, John C; Stachulski, Andrew V

2010-12-08

306

Targeted delivery of vitamin D to the colon using ?-glucuronides of vitamin D: therapeutic effects in a murine model of inflammatory bowel disease.  

PubMed

1,25-Dihydroxyvitamin D(3) [1,25(OH)(2)D] has been shown to inhibit development of dextran sodium sulfate (DSS)-induced colitis in mice but can also cause hypercalcemia. The aim of this study was to evaluate whether ?-glucuronides of vitamin D could deliver 1,25(OH)(2)D to the colon to ameliorate colitis while reducing the risk of hypercalcemia. Initial studies demonstrated that bacteria residing in the lower intestinal tract were capable of liberating 1,25(OH)(2)D from 1,25-dihydroxyvitamin D(3)-25-?-glucuronide [?-gluc-1,25(OH)(2)D]. We also determined that a much greater upregulation of the vitamin D-dependent 24-hydroxylase gene (Cyp24) was induced in the colon by treatment of mice with an oral dose of ?-gluc-1,25(OH)(2)D than 1,25(OH)(2)D, demonstrating targeted delivery of 1,25(OH)(2)D to the colon. We then tested ?-glucuronides of vitamin D in the mouse DSS colitis model in two studies. In mice receiving DSS dissolved in distilled water and treated with 1,25(OH)(2)D or ?-gluc-1,25(OH)(2)D, severity of colitis was reduced. Combination of ?-gluc-1,25(OH)(2)D with 25-hydroxyvitamin D(3)-25-?-glucuronide [?-gluc-25(OH)D] resulted in the greatest reduction of colitis lesions and symptoms in DSS-treated mice. Plasma calcium concentrations were lower in mice treated with ?-gluc-1,25(OH)(2)D alone or in combination with ?-gluc-25(OH)D than in mice treated with 1,25(OH)(2)D, which were hypercalcemic at the time of death. ?-Glucuronides of vitamin D compounds can deliver 1,25(OH)(2)D to the lower intestine and can reduce symptoms and lesions of acute colitis in this model. PMID:22114117

Goff, Jesse P; Koszewski, Nicholas J; Haynes, Joseph S; Horst, Ronald L

2011-11-23

307

A high-throughput U-HPLC-MS/MS assay for the quantification of mycophenolic acid and its major metabolites mycophenolic acid glucuronide and mycophenolic acid acyl-glucuronide in human plasma and urine.  

PubMed

Mycophenolic acid (MPA) is used as an immunosuppressant after organ transplantation and for the treatment of immune diseases. There is increasing evidence that therapeutic drug monitoring and plasma concentration-guided dose adjustments are beneficial for patients to maintain immunosuppressive efficacy and to avoid toxicity. The major MPA metabolite that can be found in high concentrations in plasma is MPA glucuronide (MPAG). A metabolite usually present at lower concentrations, MPA acyl-glucuronide (AcMPAG), has been implicated in some of the adverse effects of MPA. We developed and validated an automated high-throughput ultra-high performance chromatography-tandem mass spectrometry (U-HPLC-MS/MS) assay using liquid-handling robotic extraction for the quantification of MPA, MPAG, and AcMPAG in human EDTA plasma and urine. The ranges of reliable response were 0.097 (lower limit of quantitation) to 200 ?g/mL for MPA and MPAG and 0.156-10 ?g/mL for AcMPAG in human urine and plasma. The inter-day accuracies were 94.3-104.4%, 93.8-105.0% and 94.4-104.7% for MPA, MPAG and AcMPAG, respectively. Inter-day precisions were 0.7-7.8%, 0.9-6.9% and 1.6-8.6% for MPA, MPAG and AcMPAG. No matrix interferences, ion suppression/enhancement and carry-over were detected. The total assay run time was 2.3 min. The assay met all predefined acceptance criteria and the quantification of MPA was successfully cross-validated with an LC-MS/MS assay routinely used for clinical therapeutic drug monitoring. The assay has proven to be robust and reliable during the measurement of samples from several pharmacokinetics trials. PMID:21839692

Klepacki, Jacek; Klawitter, Jelena; Bendrick-Peart, Jamie; Schniedewind, Bjorn; Heischmann, Svenja; Shokati, Touraj; Christians, Uwe; Klawitter, Jost

2011-08-02

308

Non-enzymatic cyclization of creatine ethyl ester to creatinine.  

PubMed

Creatine ethyl ester was incubated at 37 degrees C in both water and phosphate-buffered saline and the diagnostic methylene resonances in the (1)H NMR spectrum were used to identify the resultant products. It was found that mild aqueous conditions result in the cyclization of creatine ethyl ester to provide inactive creatinine as the exclusive product, and this transformation becomes nearly instantaneous as the pH approaches 7.4. This study demonstrates that mild non-enzymatic conditions are sufficient for the cyclization of creatine ethyl ester into creatinine, and together with previous results obtained under enzymatic conditions suggests that there are no physiological conditions that would result in the production of creatine. It is concluded that creatine ethyl ester is a pronutrient for creatinine rather than creatine under all physiological conditions encountered during transit through the various tissues, thus no ergogenic effect is to be expected from supplementation. PMID:19660433

Giese, Matthew W; Lecher, Carl S

2009-08-04

309

Creatine ethyl ester: a new substrate for creatine kinase.  

PubMed

The creatine kinase/phosphocreatine system plays a key role in cell energy buffering and transport, particularly in cells with high or fluctuating energy requirements, like neurons, i.e. it participates in the energetic metabolism of the brain. Creatine depletion causes several nervous system diseases, alleviated by phosphagen supplementation. Often, the supplementation contains both creatine and creatine ethyl ester, known to improve the effect of creatine through an unknown mechanism. In this work we showed that purified creatine kinase is able to phosphorilate the creatine ethyl ester. The K(m) and V(max) values, as well as temperature and pH optima were determined. Conversion of the creatine ethyl ester into its phosphorylated derivative, sheds light on the role of the creatine ethyl ester as an energy source in supplementation for selected individuals. PMID:22642114

Ravera, S; Adriano, E; Balestrino, M; Panfoli, I

310

Lignin Biodegradation and the Production of Ethyl Alcohol from Cellulose.  

National Technical Information Service (NTIS)

During the last few years our group has been engaged in developing a biochemical process for the conversion of lignocellulosic materials to ethyl alcohol. Lignin is a barrier to complete cellulose saccharification in this process, but chemical and physica...

S. L. Rosenberg C. R. Wilke

1981-01-01

311

Attenuation of Ethyl Alcohol Intoxication with Alpha-2 Adrenoceptor Antagonists.  

National Technical Information Service (NTIS)

A method is provided for attenuating the intoxicating effects of ethyl alcohol in a patient, by administering to a patient in need thereof, an alpha-2 adrenoceptor antagonist compound. Two preferred compounds useful in the present invention, each being a ...

M. Linnoila R. Lister M. Durcan

1989-01-01

312

Syntheses and Characterisations of Derivatives of Ethyl Centralite.  

National Technical Information Service (NTIS)

A comprehensive description is given of the preparations of all the major derivatives of ethyl Centralites that are found in nitrocellulose based propellants. These compounds are fully characterised by spectroscopic and thin-layer techniques. Keywords: Et...

N. J. Curtis

1987-01-01

313

Synthesis and Preliminary Chemotherapeutic Evaluation of the Fully C-Linked Glucuronide of N-(4-Hydroxyphenyl) retinamide (4-HPR)  

PubMed Central

All-trans retinoic acid (atRA) analogues such as N-(4-hydroxyphenyl) retinamide (4-HPR) are effective chemopreventive and chemotherapeutic agents but their utility has been hampered by dose-limiting side effects. The glucuronide derivatives of 4-HPR, the oxygen-linked 4-HPROG and the carbon-linked 4-HPRCG, have been found to be more effective agents. The synthetic route to the fully C-linked analogue of 4-HPROG (4-HBRCG), which employs Suzuki coupling and Umpolung chemistries as key methodologies, is shown. The results of this study show 4-HBRCG to be an effective chemotherapeutic agent in a rat mammary tumor model while being devoid of classical retinoid toxicities.

Walker, Joel R.; Alshafie, Galal; Nieves, Nirca; Ahrens, Jamie; Clagett-Dame, Margaret; Abou-Issa, Hussein; Curley, Robert W.

2006-01-01

314

Ethyl-Substituted Erythromycin Derivatives Produced by Directed Metabolic Engineering  

Microsoft Academic Search

A previously unknown chemical structure, 6-desmethyl-6-ethylerythromycin A (6-ethylErA), was produced through directed genetic manipulation of the erythromycin (Er)-producing organism Saccharopolyspora erythraea. In an attempt to replace the methyl side chain at the C-6 position of the Er polyketide backbone with an ethyl moiety, the methylmalonate-specific acyltransferase (AT) domain of the Er polyketide synthase was replaced with an ethylmalonate-specific AT domain

D. L. Stassi; S. J. Kakavas; K. A. Reynolds; G. Gunawardana; S. Swanson; D. Zeidner; M. Jackson; H. Liu; A. Buko; L. Katz

1998-01-01

315

Fractionation of urea-pretreated squid visceral oil ethyl esters  

Microsoft Academic Search

Ethyl esters of squid (Illex argentinus) visceral oil contained 11.8% eicosapentaenoic acid (EPA) and 14.9% docosahexaenoic acid (DHA). The esters were treated with\\u000a urea to increase the contents of EPA and DHA. The non-urea complexing ethyl esters of squid visceral oil contained 28.2% EPA\\u000a and 35.6% DHA. This mixture was fractionated by molecular distillation to further increase the EPA or

Lucy Sun Hwang

2001-01-01

316

Optimization of Synthesis of Ethyl Isovalerate Using Rhizomucor miehei Lipase  

Microsoft Academic Search

Immobilized lipase from Rhizomucor miehei (Lipozyme IM-20) was used to catalyze the esterification reaction between isovaleric acid and ethanol to synthesize ethyl isovalerate in n-hexane. Response surface methodology based on a four-variable, five-level, central composite rotatable design was employed to optimize four important reaction variables—enzyme\\/substrate (E\\/S) ratio, substrate concentration, incubation time, and temperature—affecting the synthesis of ethyl isovalerate. The optimum

G. V. Chowdary; S. G. Prapulla

2003-01-01

317

Atmospheric Oxidation Mechanisms for Diethyl Ether and its Oxidation Products, Ethyl Formate and Ethyl Acetate.  

NASA Astrophysics Data System (ADS)

Carbon-containing compounds are present in the earth's atmosphere as the result of emissions from natural and anthropogenic sources. Their oxidation in the atmosphere, initiated by such oxidants as OH, ozone, and nitrate radicals, leads to potentially harmful secondary pollutants such as ozone, carbonyl species, organic acids and aerosols. Ethers and esters are two classes of compounds that contribute to the complex array of organic compounds found in anthropogenically-influenced air. Additional ester is present as a result of the oxidation of the ethers. In this paper, the oxidation of diethyl ether and its two main oxidation products, ethyl formate and ethyl acetate, are studied over ranges of temperature, oxygen partial pressure, and NOx concentration, using an environmental chamber / FTIR absorption technique. Major end-products (the esters from diethyl ether; organic acids and anhydrides from the esters) are quantified, and these data are interpreted in terms of the chemistry of the various alkoxy and peroxy radicals generated. Emphasis is placed on the effects of chemical activation on the behavior of the alkoxy radicals, as well as on a novel peroxy radical rearrangement that may contribute to the observed products of ether oxidation under some conditions. Finally, the data are used, in conjunction with data on similar species, to provide a general representation of ether and ester oxidation in the atmosphere.

Orlando, J. J.; Tyndall, G. S.

2006-12-01

318

REMOVAL OF ACETIC ACID IMPURITIES FROM ETHYL ACETATE BY ADSORPTION ON ION EXCHANGE RESINS  

Microsoft Academic Search

Removal of acetic acid impurities from ethyl acetate was attempted by sorption on basic ion-exchange resins. Kinetic studies showed that acid removal is controlled by intraparticle resistance from both ethyl acetate and alcohol. Breakthrough curves for uptake of the acid from ethyl acetate were obtained at different flow rates and concentrations. Desorption studies were performed using both ethyl acetate and

H. M. Anasthas; V. G. Gaikar

2001-01-01

319

(2-Ethyl-2-oxazoline-?N)bis(N-ethyl-N-phenyl-dithio-carbamato-?2 S,S?)cadmium  

PubMed Central

In the title compound, [Cd(C9H10NS2)2(C5H9NO)], the CdII atom is five-coordinated in a distorted square-pyramidal geometry by four S atoms from two chelating N-ethyl-N-phenyl dithio­carbamate ligands and one N atom from a 2-ethyl-2-oxazoline ligand. Inter­molecular C—H?? inter­actions are observed in the crystal structure.

Onwudiwe, Damian C.; Strydom, Christien A.; Hosten, Eric C.

2012-01-01

320

High-performance liquid chromatographic method for the simultaneous determination of the camptothecin derivative irinotecan hydrochloride, CPT-11, and its metabolites SN-38 and SN-38 glucuronide in rat plasma with a fully automated on-line solid-phase extraction system, PROSPEKT.  

PubMed

We established a high-performance liquid chromatography (HPLC) method for the simultaneous determination of the camptothecin (CPT) derivative, irinotecan hydrochloride (CPT-11) and its metabolites, 7-ethyl-10-hydroxycamptothecin (SN-38) and SN-38 glucuronide (SN-38G) in rat plasma with a fully automated on-line solid-phase extraction system, PROSPEKT. Plasma samples were pretreated with 0.146 M H3PO4 to inactivate carboxylesterase and beta-glucuronidase in rat plasma, and added with the internal standard solution (0.146 M H3PO4 containing 1 microgram/ml CPT) and then analyzed. The method was validated for CPT-11 (5 to 25,000 ng/ml), SN-38 (5 to 2500 ng/ml) and SN-38G (2.5 to 500 ng/ml). This method enabled the determination of many samples within a relatively short time with easy sample preparation. It also had four advantages compared with conventional determination methods, i.e. automation of a complicated sample preparation, time-saving by the simultaneous determination of three compounds, the direct determination of SN-38G, and the small amount of plasma required for the determination. PMID:10219676

Kurita, A; Kaneda, N

1999-03-19

321

Determining the partial photoionization cross-sections of ethyl radicals.  

PubMed

Using a crossed laser-molecular beam scattering apparatus, these experiments photodissociate ethyl chloride at 193 nm and detect the Cl and ethyl products, resolved by their center-of-mass recoil velocities, with vacuum ultraviolet photoionization. The data determine the relative partial cross-sections for the photoionization of ethyl radicals to form C2H5+, C2H4+, and C2H3+ at 12.1 and 13.8 eV. The data also determine the internal energy distribution of the ethyl radical prior to photoionization, so we can assess the internal energy dependence of the photoionization cross-sections. The results show that the C2H4++H and C2H3++H2 dissociative photoionization cross-sections strongly depend on the photoionization energy. Calibrating the ethyl radical partial photoionization cross-sections relative to the bandwidth-averaged photoionization cross-section of Cl atoms near 13.8 eV allows us to use these data in conjunction with literature estimates of the Cl atom photoionization cross-sections to put the present bandwidth-averaged cross-sections on an absolute scale. The resulting bandwidth-averaged cross-section for the photoionization of ethyl radicals to C2H5+ near 13.8 eV is 8+/-2 Mb. Comparison of our 12.1 eV data with high-resolution ethyl radical photoionization spectra allows us to roughly put the high-resolution spectrum on the same absolute scale. Thus, one obtains the photoionization cross-section of ethyl radicals to C2H5+ from threshold to 12.1 eV. The data show that the onset of the C2H4++H dissociative photoionization channel is above 12.1 eV; this result offers a simple way to determine whether the signal observed in photoionization experiments on complex mixtures is due to ethyl radicals. We discuss an application of the results for resolving the product branching in the O+allyl bimolecular reaction. PMID:17760439

FitzPatrick, B L; Maienschein-Cline, M; Butler, L J; Lee, S-H; Lin, J J

2007-08-31

322

Metabolic profile of FYX-051 (4-(5-pyridin-4-yl-1h-[1,2,4]triazol-3-yl)pyridine-2-carbonitrile) in the rat, dog, monkey, and human: identification of N-glucuronides and N-glucosides.  

PubMed

FYX-051, 4-(5-pyridin-4-yl-1H-[1,2,4]triazol-3-yl)pyridine-2-carbonitrile, is a novel xanthine oxidoreductase inhibitor that can be used for the treatment of gout and hyperuricemia. We examined the metabolism of FYX-051 in rats, dogs, monkeys, and human volunteers after the p.o. administration of this inhibitor. The main metabolites in urine were pyridine N-oxide in rats, triazole N-glucoside in dogs, and triazole N-glucuronide in monkeys and humans, respectively. Furthermore, N-glucuronidation and N-glucosidation were characterized by two types of conjugation: triazole N(1)- and N(2)-glucuronidation and N(1)- and N(2)-glucosidation, respectively. N(1)- and N(2)-glucuronidation was observed in each species, whereas N(1)- and N(2)-glucosidation was mainly observed in dogs. With regard to the position of conjugation, N(1)-conjugation was predominant; this resulted in a considerably higher amount of N(1)-conjugate in each species than N(2)-conjugate. The present results indicate that the conjugation reaction observed in FYX-051 metabolism is unique, i.e., N-glucuronidation and N-glucosidation occur at the same position of the triazole ring, resulting in the generation of four different conjugates in mammals. In addition, a urinary profile of FYX-051 metabolites in monkeys and humans was relatively similar; triazole N-glucuronides were mainly excreted in urine. PMID:16914512

Nakazawa, Takashi; Miyata, Kengo; Omura, Koichi; Iwanaga, Takashi; Nagata, Osamu

2006-08-16

323

Determination of 3-trifluoromethyl-4-nitrophenol and 3-trifluoromethyl-4-nitrophenol glucuronide in edible fillet tissue of rainbow trout and channel catfish by solid-phase extraction and liquid chromatography.  

PubMed

3-Trifluoromethyl-4-nitrophenol (TFM) is a pesticide used for the selective control of sea lampreys (Petromyzon marinus) in stream and river tributaries of the Great Lakes. To determine concentrations of TFM and TFM glucuronide in the edible fillet tissue of fish during sea lamprey control treatments, an analytical method was developed to determine the concentrations of these residues in rainbow trout (Oncorhynchus mykiss; RBT) and channel catfish (Ictalurus punctatis; CCF). Homogenized fillets were extracted with methanol-water (80 + 20). TFM and TFM glucuronide were isolated from coextractives by C18 solid-phase extraction. TFM glucuronide was hydrolyzed to TFM by the addition of beta-glucuronidase to the TFM glucuronide extract. The extracts were analyzed separately by liquid chromatography with UV-visible detection. Recoveries from TFM-fortified CCF and RBT tissues were 84.1 and 96.1%, respectively. The method detection limits (MDLs) are 2.4 ng/g for TFM-fortified tissues of CCF and 3 ng/g for those of RBT. Recoveries were 78.8 and 77% from TFM glucuronide-fortified CCF and RBT tissues, respectively. The MDLs for TFM glucuronide-fortified tissues are 3.5 and 6.9 ng/g for CCF and RBT, respectively. PMID:11324603

Hubert, T D; Vue, C; Bernardy, J A; Van Horsen, D L; Rossulek, M I

324

Production of monoclonal antibody to herbicide fenoxaprop-ethyl.  

PubMed

Fenoxaprop-ethyl is a selective aryloxyphenoxypropionate herbicide used widely to control annual and perennial grasses. A monoclonal antibody (MAb) against fenoxaprop-ethyl (FE), designated as 3E6B9C, was produced and had very low cross-reactivity with some of its structural analogs, such as clodinafop-propargyl, diclofop-methyl, lactofen, and quizalofop-p-ethyl. An indirect competitive enzyme-linked immunosorbent assay (icELISA) was developed. The concentration of R-(+)-fenoxaprop-ethyl (R-FE) producing 50% of inhibition (IC(50)) and the working range of icELISA were 3.1?ng/mL and 0.6-29?ng/mL, respectively. This assay is also sensitive to R-fenoxaprop, S-(-)-fenoxaprop-ethyl, and metamifop with IC(50) of 3.4, 2.7, and 3.5?ng/mL, respectively. The recoveries of R-FE in soil samples with the icELISA were 86-102%. PMID:22008074

Cui, Yongliang; Nan, Tiegui; Tan, Guiyu; Li, Qing X; Wang, Baomin; Liu, Shangzhong

2011-10-01

325

Ethyl-substituted erythromycin derivatives produced by directed metabolic engineering.  

PubMed

A previously unknown chemical structure, 6-desmethyl-6-ethylerythromycin A (6-ethylErA), was produced through directed genetic manipulation of the erythromycin (Er)-producing organism Saccharopolyspora erythraea. In an attempt to replace the methyl side chain at the C-6 position of the Er polyketide backbone with an ethyl moiety, the methylmalonate-specific acyltransferase (AT) domain of the Er polyketide synthase was replaced with an ethylmalonate-specific AT domain from the polyketide synthase involved in the synthesis of the 16-member macrolide niddamycin. The genetically altered strain was found to produce ErA, however, and not the ethyl-substituted derivative. When the strain was provided with precursors of ethylmalonate, a small quantity of a macrolide with the mass of 6-ethylErA was produced in addition to ErA. Because substrate for the heterologous AT seemed to be limiting, crotonyl-CoA reductase, a primary metabolic enzyme involved in butyryl-CoA production in streptomycetes, was expressed in the strain. The primary macrolide produced by the reengineered strain was 6-ethylErA. PMID:9636144

Stassi, D L; Kakavas, S J; Reynolds, K A; Gunawardana, G; Swanson, S; Zeidner, D; Jackson, M; Liu, H; Buko, A; Katz, L

1998-06-23

326

Ethyl-substituted erythromycin derivatives produced by directed metabolic engineering  

PubMed Central

A previously unknown chemical structure, 6-desmethyl-6-ethylerythromycin A (6-ethylErA), was produced through directed genetic manipulation of the erythromycin (Er)-producing organism Saccharopolyspora erythraea. In an attempt to replace the methyl side chain at the C-6 position of the Er polyketide backbone with an ethyl moiety, the methylmalonate-specific acyltransferase (AT) domain of the Er polyketide synthase was replaced with an ethylmalonate-specific AT domain from the polyketide synthase involved in the synthesis of the 16-member macrolide niddamycin. The genetically altered strain was found to produce ErA, however, and not the ethyl-substituted derivative. When the strain was provided with precursors of ethylmalonate, a small quantity of a macrolide with the mass of 6-ethylErA was produced in addition to ErA. Because substrate for the heterologous AT seemed to be limiting, crotonyl-CoA reductase, a primary metabolic enzyme involved in butyryl-CoA production in streptomycetes, was expressed in the strain. The primary macrolide produced by the reengineered strain was 6-ethylErA.

Stassi, D. L.; Kakavas, S. J.; Reynolds, K. A.; Gunawardana, G.; Swanson, S.; Zeidner, D.; Jackson, M.; Liu, H.; Buko, A.; Katz, L.

1998-01-01

327

Development of a fast screening and confirmatory method by liquid chromatography-quadrupole-time-of-flight mass spectrometry for glucuronide-conjugated methyltestosterone metabolite in tilapia.  

PubMed

This paper describes the development of a fast method to screen and confirm methyltestosterone 17-O-glucuronide (MT-glu) in tilapia bile. The method consists of solid-phase extraction (SPE) followed by high-performance liquid chromatography-mass spectrometry. The system used was an Agilent 6530 Q-TOF with an Agilent Jet stream electrospray ionization interface. The glucuronide detected in the bile was characterized as MT-glu by comparison with a chemically synthesized standard. MT-glu was detected in bile for up to 7 days after dosing. Semiquantification was done with matrix-matched calibration curves, because MT-glu showed signal suppression due to matrix effects. This method provides a suitable tool to monitor the illegal use of methyltestosterone in tilapia culture. PMID:22548460

Amarasinghe, Kande; Chu, Pak-Sin; Evans, Eric; Reimschuessel, Renate; Hasbrouck, Nicholas; Jayasuriya, Hiranthi

2012-05-09

328

Species differences in the biotransformation of an alpha 4 beta 2 nicotinic acetylcholine receptor partial agonist: the effects of distinct glucuronide metabolites on overall compound disposition.  

PubMed

The metabolism and disposition of (1R,5S)-2,3,4,5-tetrahydro-7-(trifluoromethyl)-1,5-methano-1H-3-benzazepine (1), an alpha(4)beta(2) nicotinic acetylcholine receptor partial agonist, was investigated in Sprague-Dawley rats and cynomolgus monkeys receiving (1R,5S)-2,3,4,5-tetrahydro-7-(trifluoromethyl)-1,5-methano-1H-4[(14)C]-3- benzazepine hydrochloride ([(14)C]1) orally. Although both species chiefly (>or=62%) cleared 1 metabolically, species-specific dispositional profiles were observed for both 1 and total radioactivity. Radioactivity was excreted equally in the urine and feces of intact rats but largely (72%) in bile in bile duct-cannulated animals. In monkeys, radioactivity recoveries were 50-fold greater in urine than feces and minimal (<5%) in bile. Both species metabolized 1 similarly: four-electron oxidation to one of four amino acids or two lactams (minor) and glucuronide formation (major). In rats, the latter pathway predominantly formed an N-carbamoyl glucuronide (M6), exclusively present in bile (69% of dose), whereas in monkeys it afforded an N-O-glucuronide (M5), a minor biliary component (4%) but the major plasma (62%) and urinary (42%) entity. In rats, first-pass hepatic conversion of 1 to M6, which was confirmed in rat hepatocytes, and its biliary secretion resulted in the indirect enterohepatic cycling of 1 via M6 and manifested in double-humped plasma concentration-time curves and long t(1/2) for both 1 and total radioactivity. In monkeys, in which only M5 was formed, double-humped plasma concentration-time curves were absent, and moderate t(1/2) for both 1 and total radioactivity were observed. A seemingly subtle, yet critical, difference in the chemical structures of these two glucuronide metabolites considerably affected the overall disposition of 1 in rats versus monkeys. PMID:19910512

Shaffer, Christopher L; Gunduz, Mithat; Ryder, Tim F; O'Connell, Thomas N

2009-11-12

329

Interaction of hesperetin glucuronide conjugates with human BCRP, MRP2 and MRP3 as detected in membrane vesicles of overexpressing baculovirus-infected Sf9 cells.  

PubMed

The citrus flavonoid hesperetin (4'-methoxy-3',5,7-trihydroxyflavanone) is the aglycone of hesperidin, the major flavonoid present in sweet oranges. Hesperetin 7-O-glucuronide (H7G) and hesperetin 3'-O-glucuronide (H3'G) are the two most abundant metabolites of hesperetin in vivo. In this study, their interaction with specific ABC transporters, believed to play a role in the disposition and bioavailability of hesperetin, was studied using Sf9 membranes from cells overexpressing human BCRP (ABCG2), MRP2 (ABCC2) and MRP3 (ABCC3). Both H7G and H3'G were tested for their potential to activate and inhibit ATPase activity, and to inhibit vesicular transport by these transporters. Both H7G and H3'G demonstrated interaction with all tested ABC transporters, especially with BCRP and MRP3. An interesting difference between H7G and H3'G was seen with respect to the interaction with BCRP: H7G stimulated the ATPase activity of BCRP up to 76% of the maximal effect generated by the reference activator sulfasalazine, with an EC(50) of 0.45 µM, suggesting that H7G is a high affinity substrate of BCRP, whereas H3'G did not stimulate BCRP ATPase activity. Only moderate inhibition of BCRP ATPase activity at high H3'G concentrations was observed. This study provides information on the potential of hesperetin glucuronide conjugates to act as specific ABC transporter substrates or inhibitors and indicates that regio-specific glucuronidation could affect the disposition of hesperetin. PMID:22083890

Brand, Walter; Oosterhuis, Berend; Krajcsi, Peter; Barron, Denis; Dionisi, Fabiola; van Bladeren, Peter J; Rietjens, Ivonne M C M; Williamson, Gary

2011-11-21

330

Quantitation of entacapone glucuronide in rat plasma by on-line coupled restricted access media column and liquid chromatography–tandem mass spectrometry  

Microsoft Academic Search

A column-switching liquid chromatography–electrospray ionization-tandem mass spectrometric (LC–ESI-MS–MS) method was developed for the direct analysis of entacapone glucuronide in plasma. The plasma samples (5 ?l) were injected onto a C18-alkyl-diol silica (ADS) column and the matrix compounds were washed to waste with a mixture of 20 mM ammonium acetate solution at pH 4.0–acetonitrile (97:3). The retained analyte fraction containing (E)-

Helena Keski-Hynnilä; Knut Raanaa; Markus Forsberg; Pekka Männistö; Jyrki Taskinen; Risto Kostiainen

2001-01-01

331

Measurement of intact sulfate and glucuronide phytoestrogen conjugates in human urine using isotope dilution liquid chromatography-tandem mass spectrometry with [ 13 C 3] isoflavone internal standards  

Microsoft Academic Search

A method has been developed for the analysis of phytoestrogens and their conjugates in human urine using liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS\\/MS). Stable isotopically labeled [13C3]daidzein and [13C3]genistein were synthesized and used as internal standards for isotope dilution mass spectrometry. Free aglycons and intact glucuronide, sulfate, diglucuronide, disulfate, and mixed sulfoglucuronide conjugates of isoflavones and lignans were

Don B Clarke; Antony S Lloyd; Nigel P Botting; Mark F Oldfield; Paul W Needs; Helen Wiseman

2002-01-01

332

Simultaneous determination of cortisol, dexamethasone, methylprednisolone, prednisone, prednisolone, mycophenolic acid and mycophenolic acid glucuronide in human plasma utilizing liquid chromatography–tandem mass spectrometry  

Microsoft Academic Search

Chronic combination immunosuppressive regimens are commonly prescribed to renal transplant recipients. To develop an assay method for pharmacokinetic studies and therapeutic drug monitoring of multiple immunosuppressives, a liquid chromatography–tandem mass spectrometry (LC\\/MS\\/MS) approach for the simultaneous analysis of several glucocorticoids, mycophenolic acid (MPA) and mycophenolic acid glucuronide (MPAG) was investigated. The resultant method utilized a gradient reverse phase separation over

Robin DiFrancesco; Valerie Frerichs; Julie Donnelly; Colleen Hagler; Jill Hochreiter; Kathleen M. Tornatore

2007-01-01

333

Quantification of glucuronidated and sulfated steroids in human urine by ultra-high pressure liquid chromatography quadrupole time-of-flight mass spectrometry  

Microsoft Academic Search

The urinary steroid profile is constituted by anabolic androgenic steroids, including testosterone and its relatives, that\\u000a are extensively metabolized into phase II sulfated or glucuronidated steroids. The use of liquid chromatography coupled to\\u000a mass spectrometry (LC-MS) is an issue for the direct analysis of conjugated steroids, which can be used as urinary markers\\u000a of exogenous steroid administration in doping analysis,

Flavia Badoud; Elia Grata; Julien Boccard; Davy Guillarme; Jean-Luc Veuthey; Serge Rudaz; Martial Saugy

2011-01-01

334

Simultaneous determination of morphine, oxycodone, morphine-3-glucuronide, and noroxycodone concentrations in rat serum by high performance liquid chromatography–electrospray ionization–tandem mass spectrometry  

Microsoft Academic Search

An assay using high performance liquid chromatography (HPLC)–electrospray ionization–tandem mass spectrometry (ESI–MS–MS) was developed for simultaneously determining concentrations of morphine, oxycodone, morphine-3-glucuronide, and noroxycodone, in 50?l samples of rat serum. Deuterated (d3) analogues of each compound were used as internal standards. Samples were treated with acetonitrile to precipitate plasma proteins; acetonitrile was removed from the supernatant by centrifugal evaporation before

Stephen R. Edwards; Maree T. Smith

2005-01-01

335

Liquid chromatography–tandem mass spectrometry method for measurement of nicotine N-glucuronide: A marker for human UGT2B10 inhibition  

Microsoft Academic Search

Nicotine is considered to be a specific substrate for UGT2B10, an isoform of human uridine diphosphate glucuronosyltransferase (UGT). In the present study, a sensitive and selective liquid chromatography\\/tandem mass spectrometry (LC–MS–MS) method for quantification of nicotine N-glucuronide in pooled human liver microsomal incubates was developed and validated. Proteins in a 200?L aliquot of incubation solution were precipitated by adding 40?L

Jian Guo; Diansong Zhou; Scott W. Grimm

2011-01-01

336

Development and validation of screening and confirmatory methods for the detection of chloramphenicol and chloramphenicol glucuronide using SPR biosensor and liquid chromatography–tandem mass spectrometry  

Microsoft Academic Search

Biacore Q biosensor and liquid chromatography–tandem mass spectrometry (LC–MS\\/MS) based methods for the screening and confirmation of trace levels of chloramphenicol (CAP) and the mammalian metabolite chloramphenicol glucuronide (CAP-Glu) is reported. Both methods employ solvent extraction and clean-up by solid phase extraction (SPE) prior to analysis. The biosensor screening method utilises surface plasmon resonance (SPR) to determine chloramphenicol concentration in

H. M. Ashwin; S. L. Stead; J. C. Taylor; J. R. Startin; S. F. Richmond; V. Homer; T. Bigwood; M. Sharman

2005-01-01

337

Sensitive high-performance liquid chromatography–tandem mass spectrometry method for quantitative analysis of mycophenolic acid and its glucuronide metabolites in human plasma and urine  

Microsoft Academic Search

A method to determine total and free mycophenolic acid (MPA) and its metabolites, the phenolic (MPAG) and acyl (AcMPAG) glucuronides, using HPLC and mass spectrometry was developed. Mean recoveries in plasma and urine samples were >85%, and the lower limits of quantification for MPA, MPAG and AcMPAG were 0.05, 0.05 and 0.01mg\\/L, respectively. For plasma, the assay was linear over

Marie-Odile Benoit-Biancamano; Patrick Caron; Éric Lévesque; Robert Delage; Félix Couture; Chantal Guillemette

2007-01-01

338

Fragrance material review on 2-(p-tolyloxy)ethyl acetate.  

PubMed

A toxicologic and dermatologic review of 2-(p-tolyloxy)ethyl acetate when used as a fragrance ingredient is presented. 2-(p-tolyloxy)ethyl acetate is a member of the fragrance structural group aryl alkyl alcohol simple acid esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for 2-(p-tolyloxy)ethyl acetate were evaluated, then summarized, and includes physical properties data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22414652

McGinty, D; Letizia, C S; Api, A M

2012-03-04

339

NEW GROUND-STATE MEASUREMENTS OF ETHYL CYANIDE  

SciTech Connect

The spectrum of ethyl cyanide, or propionitrile (CH{sub 3}CH{sub 2}CN), has been repeatedly observed in the interstellar medium with large column densities and surprisingly high temperatures in hot core sources. The construction of new, more sensitive, observatories accessing higher frequencies such as Herschel, ALMA, and SOFIA have made it important to extend the laboratory data for ethyl cyanide to coincide with the capabilities of the new instruments. We report extensions of the laboratory measurements of the rotational spectrum of ethyl cyanide in its ground vibrational state to 1.6 THz. A global analysis of the ground state, which includes all of the previous data and 3356 newly assigned transitions, has been fitted to within experimental error to J = 132, K = 36, using both Watson A-reduced and Watson S-reduced Hamiltonians.

Brauer, Carolyn S.; Pearson, John C.; Drouin, Brian J.; Yu, Shanshan [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)], E-mail: Carolyn.S.Brauer@jpl.nasa.gov

2009-09-01

340

Health and Environmental Effects Profile for ethyl methacrylate  

SciTech Connect

The Health and Environmental Effects Profile for ethyl methacrylate was prepared to support listings of hazardous constituents of a wide range of waste streams under Section 3001 of the Resource Conservation and Recovery Act (RCRA) and to provide health-related limits for emergency actions under Section 101 of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA). Both published literature and information obtained from Agency program office files were evaluated as they pertained to potential human health, aquatic life and environmental effects. Quantitative estimates are presented provided sufficient data are available. Ethyl methacrylate has been determined to be a systemic toxicant. An acceptable daily intake (ADI) for ethyl methacrylate is 0.086 mg/kg/day for oral exposure.

Not Available

1986-06-01

341

Bis(ethyl-eneglycolato-?2 O,O?)tellurium(IV)  

PubMed Central

The title compound, C4H8O4Te, crystallized from a solution of Te4+ in ethyl­ene glycol. The TeIV atom is in a distorted seesaw coordination defined by four O atoms from two different ethyl­eneglycate ligands. The C atoms of the ethyl­eneglycate ligands are disorderd over two positions, with population parameters of 50.3?(6) and 49.7?(6)% indicating a statistical distribution. Due to the possibility to transform the primitive monoclinic unit cell into a metrically ortho­rhom­bic C unit cell, the data are twinned and were refined with the twin law -100/0-10/101 with the relative scale factor refining to 1.82?(4)% for the minor component.

Brooks, Neil R.; Wu, Minxian; Van Meervelt, Luc; Binnemans, Koen; Fransaer, Jan

2013-01-01

342

Ethyl acetate: X-ray, solvent and computed structures.  

PubMed

Ethyl acetate (ethyl ethanoate) was crystallized in situ and the crystal structure was determined. In the solid, the molecule is flat with trans conformation. The geometric details of ethyl acetate as a solvate are analyzed statistically using the Cambridge Structural Database, uncovering a high degree of hidden disorder. Despite the disorder, they exhibit a preference of the trans over the gauche isomer, with a negligible contribution of the cis isomer. These results are compared to ab initio calculations on both solid-state and molecular level. For the molecular structures, the computed energy differences of the isomers match the statistics found as a solvent. Several DFT-D2 methods used to calculate the solid state yield results that differ significantly from the experiment. PMID:23108979

Boese, A Daniel; Kirchner, Michael; Echeverria, Gustavo A; Boese, Roland

2012-10-25

343

Sequential Activation of Classic PKC and Estrogen Receptor ? Is Involved in Estradiol 17ss-D-Glucuronide-Induced Cholestasis  

PubMed Central

Estradiol 17ß-d-glucuronide (E17G) induces acute cholestasis in rat with endocytic internalization of the canalicular transporters bile salt export pump (Abcb11) and multidrug resistance-associated protein 2 (Abcc2). Classical protein kinase C (cPKC) and PI3K pathways play complementary roles in E17G cholestasis. Since non-conjugated estradiol is capable of activating these pathways via estrogen receptor alpha (ER?), we assessed the participation of this receptor in the cholestatic manifestations of estradiol glucuronidated-metabolite E17G in perfused rat liver (PRL) and in isolated rat hepatocyte couplets (IRHC). In both models, E17G activated ER?. In PRL, E17G maximally decreased bile flow, and the excretions of dinitrophenyl-glutathione, and taurocholate (Abcc2 and Abcb11 substrates, respectively) by 60% approximately; preadministration of ICI 182,780 (ICI, ER? inhibitor) almost totally prevented these decreases. In IRHC, E17G decreased the canalicular vacuolar accumulation of cholyl-glycylamido-fluorescein (Abcb11 substrate) with an IC50 of 91±1 µM. ICI increased the IC50 to 184±1 µM, and similarly prevented the decrease in the canalicular vacuolar accumulation of the Abcc2 substrate, glutathione-methylfluorescein. ICI also completely prevented E17G-induced delocalization of Abcb11 and Abcc2 from the canalicular membrane, both in PRL and IRHC. The role of ER? in canalicular transporter internalization induced by E17G was confirmed in ER?-knocked-down hepatocytes cultured in collagen sandwich. In IRHC, the protection of ICI was additive to that produced by PI3K inhibitor wortmannin but not with that produced by cPKC inhibitor Gö6976, suggesting that ER? shared the signaling pathway of cPKC but not that of PI3K. Further analysis of ER? and cPKC activations induced by E17G, demonstrated that ICI did not affect cPKC activation whereas Gö6976 prevented that of ER?, indicating that cPKC activation precedes that of ER?. Conclusion: ER? is involved in the biliary secretory failure induced by E17G and its activation follows that of cPKC.

Barosso, Ismael R.; Zucchetti, Andres E.; Boaglio, Andrea C.; Larocca, M. Cecilia; Taborda, Diego R.; Luquita, Marcelo G.; Roma, Marcelo G.; Crocenzi, Fernando A.; Sanchez Pozzi, Enrique J.

2012-01-01

344

Tris(ethyl-enediamine)zinc(II) hexa-fluorido-silicate.  

PubMed

The title compound, [Zn(C(2)H(8)N(2))(3)](SiF(6)), was synthesized ionothermally using choline chloride-imidazolidone as solvent and template provider. In the crystal structure, the anions and cations are located on special positions of site symmetry 3.2 and show a typical octa-hedral geometry. The Zn(II) ion is coordinated by six N atoms from three ethyl-enediamine mol-ecules. The crystal structure displays weak hydrogen bonding between [SiF(6)](2-) anions and the ethyl-enediamine NH hydrogen atoms. PMID:21578568

Li, Yang; Shi, Qi; Slawin, Alexandra M Z; Woollins, J Derek; Dong, Jinxiang

2009-11-07

345

Tris(ethyl-enediamine)zinc(II) hexa-fluorido-silicate  

PubMed Central

The title compound, [Zn(C2H8N2)3](SiF6), was synthesized ionothermally using choline chloride–imidazolidone as solvent and template provider. In the crystal structure, the anions and cations are located on special positions of site symmetry 3.2 and show a typical octa­hedral geometry. The ZnII ion is coordinated by six N atoms from three ethyl­enediamine mol­ecules. The crystal structure displays weak hydrogen bonding between [SiF6]2? anions and the ethyl­enediamine NH hydrogen atoms.

Li, Yang; Shi, Qi; Slawin, Alexandra M. Z.; Woollins, J. Derek; Dong, Jinxiang

2009-01-01

346

Fatty acid ethyl ester concentrations in hair and self-reported alcohol consumption in 644 cases from different origin  

Microsoft Academic Search

For diagnosis of chronic alcohol abuse, fatty acid ethyl esters (FAEE) were determined in hair samples from 644 individuals, mainly parents from child protection cases. The analysis for ethyl myristate, ethyl palmitate, ethyl oleate and ethyl stearate was performed according to a validated procedure consisting of external degreasing by two times washing with n-heptane, extraction with a mixture of dimethylsulfoxide

Silke Süße; Carl M. Selavka; Tom Mieczkowski; Fritz Pragst

2010-01-01

347

Synthesis and Characterization of New Optically Active Poly (ethyl L-lysinamide)s and Poly (ethyl L-lysinimide)s  

PubMed Central

Ethyl L-lysine dihydrochloride was reacted with three different dianhydrides to yield the poly (ethyl L-lysinimide)s (PI1?3); it was also reacted with two different diacyl chlorides to yield the poly (ethyl L-lysinamide)s (PA4-5). The resulting polymers have inherent viscosities in the range of 0.15 to 0.42?dL?g?1. These polymers are prepared from an inexpensive starting material and are optically active, potentially ion exchangeable, semicrystalline, thermally stable, and soluble in polar aprotic solvents such as DMF, DMSO, NMP, DMAc, and sulfuric acid. All of the above polymers were fully characterized by FT-IR and 1H NMR spectroscopy, elemental analysis, WAX diffraction, TGA, inherent viscosity measurement, and specific rotation.

Zahmatkesh, Saeed; Vakili, Mohammad Reza

2010-01-01

348

Synthesis and Characterization of New Optically Active Poly (ethyl L-lysinamide)s and Poly (ethyl L-lysinimide)s.  

PubMed

Ethyl L-lysine dihydrochloride was reacted with three different dianhydrides to yield the poly (ethyl L-lysinimide)s (PI(1-3)); it was also reacted with two different diacyl chlorides to yield the poly (ethyl L-lysinamide)s (PA(4-5)). The resulting polymers have inherent viscosities in the range of 0.15 to 0.42?dL?g(-1). These polymers are prepared from an inexpensive starting material and are optically active, potentially ion exchangeable, semicrystalline, thermally stable, and soluble in polar aprotic solvents such as DMF, DMSO, NMP, DMAc, and sulfuric acid. All of the above polymers were fully characterized by FT-IR and (1)H NMR spectroscopy, elemental analysis, WAX diffraction, TGA, inherent viscosity measurement, and specific rotation. PMID:22331998

Zahmatkesh, Saeed; Vakili, Mohammad Reza

2010-07-13

349

Estimating Driver Risk Using Alcohol Biomarkers, Interlock BAC Tests and Psychometric Assessments: Initial Descriptives  

PubMed Central

Aim To identify alcohol biomarker and psychometric measures that relate to drivers’ blood alcohol concentration (BAC) patterns from ignition interlock devices (IIDs). Design, Setting, Participants, Measurements In Alberta, Canada, 534 drivers, convicted of driving under the influence of alcohol (DUI), installed IIDs and agreed to participate in a research study. IID BAC tests are an established proxy for predicting future DUI convictions. Three risk groups were defined by rates of failed BAC tests. Program entry and followup blood samples (n=302, 171) were used to measure phosphatidyl ethanol (PETH), carbohydrate deficient transferrin (%CDT), gamma glutamyltransferase (GGT) and other biomarkers. Program entry urine (n=130) was analyzed for ethyl glucuronide (ETG) and ethyl sulfate (ETS). Entry hair samples were tested for fatty acid ethyl esters (FAEE) (n=92) and ETG (n=146). Psychometric measures included the DSM-4 Diagnostic Interview Schedule Alcohol Module, Alcohol Use Disorders Identification Test (AUDIT), the Timeline Followback (TLFB), the Drinker Inventory of Consequences (DRINC), and the Temptation and Restraint Inventory (TRI). Findings Except for FAEE, all alcohol biomarkers were significantly related to the interlock BAC test profiles; higher marker levels predicted higher rates of interlock BAC test failures. PETH, the strongest with an overall ANOVA F ratio of 35.5, had significant correlations with all nine of the other alcohol biomarkers and with 16 of 19 psychometric variables. Urine ETG and ETS were strongly correlated with the IID BAC tests. Conclusions The findings suggest several alcohol biomarkers and assessments could play an important role in the prediction and control of driver alcohol risk when relicensing.

Marques, Paul; Tippetts, Scott; Allen, John; Javors, Martin; Alling, Christer; Yegles, Michel; Pragst, Fritz; Wurst, Friedrich

2009-01-01

350

Evaluation of bisphenol A glucuronidation according to UGT1A1*28 polymorphism by a new LC-MS/MS assay.  

PubMed

The endocrine disruptor bisphenol A (BPA) is a frequently used chemical in the manufacture of consumer products. In humans, BPA is extensively metabolized to BPA glucuronide (BPAG) by different UDP-glucuronosyltransferase (UGT) isoforms. The study has been performed with the intention to improve the accuracy of published physiologically based pharmacokinetic models and to improve regulatory risk assessments of BPA. In order to gain insight into intestine, kidney, liver, and lung glucuronidation of BPA, human microsomes of all tested organs were used. BPAG formation followed Michaelis-Menten kinetics in the intestine and kidney, but followed substrate inhibition kinetics in the liver. Human lung microsomes did not show glucuronidation activity towards BPA. While the liver intrinsic clearance was very high (857 mL min(-1)kg body weight(-1)), the tissue intrinsic clearances for the kidney and intestine were less than 1% of liver intrinsic clearance. Since BPA is a UGT1A1 substrate, we postulated that the common UGT1A1*28 polymorphism influences BPA glucuronidation, and consequently, BPA detoxification. Hepatic tissue intrinsic clearances for UGT1A1*1/*1, UGT1A1*1/*28, and UGT1A1*28/*28 microsomes were 1113, 1075, and 284 mL min(-1)kg body weight(-1), respectively. Prior to microsomal experiments, the bioproduction of BPAG and stable isotope-labeled BPAG (BPAG(d16)) was performed for the purpose of the reliable and accurate quantification of BPAG. In addition, a sensitive LC-MS/MS analytical method for the simultaneous determination of BPA and BPAG based on two stable isotope-labeled internal standards was developed and validated. In conclusion, our in vitro results show that the liver is the main site of BPA glucuronidation (K(m) 8.9 ?M, V(max) 8.5 nmol min(-1) mg(-1)) and BPA metabolism may be significantly influenced by a person's genotype (K(m) 10.0-13.1 ?M, V(max) 3.4-16.2 nmol min(-1) mg(-1)). This discovery may be an important fact for the currently on-going worldwide BPA risk assessments and for the improvement of physiologically based pharmacokinetic models. PMID:22154984

Trdan Lušin, Tina; Roškar, Robert; Mrhar, Aleš

2011-12-01

351

A Liquid Chromatography-Tandem Mass Spectrometric Method for Quantification of Curcumin-O-Glucuronide and Curcumin in Human Plasma  

PubMed Central

Curcumin is a widely-used herbal medicine for various human diseases including inflammation and cancer. The demonstration and optimization of curcumin’s activities in the clinical setting, however, has been compromised by its poor bioavailability and the lack of analytic methods to monitor its absorption. In this paper, we report the first validated liquid chromatography-tandem mass spectrometric method for simultaneous quantification of curcumin and its major metabolite: curcumin-O-glucuronide (COG), in the linear range of 2.0–2000 ng/mL in human plasma. The intra-day and inter-day accuracies of curcumin and COG in human plasma were in the range of 91.3–111.5% and 82.7–109.2% and their co-efficiency of variations were in the range of 3.5–12.7% and 3.1–11.3%, respectively. This method was capable of detecting only COG in human plasma samples from two healthy volunteers after an oral ingestion of curcumin.

Chen, Wei; Fan-Havard, Patty; Yee, Lisa D.; Cao, Yu; Stoner, Gary D.; Chan, Kenneth K.; Liu, Zhongfa

2012-01-01

352

In Vivo-Formed versus Preformed Metabolite Kinetics of trans-Resveratrol-3-sulfate and trans-Resveratrol-3-glucuronide  

PubMed Central

Metabolites in safety testing have gained a lot of attention recently. Regulatory agencies have suggested that the kinetics of preformed and in vivo-formed metabolites are comparable. This subject has been a topic of debate. We have compared the kinetics of in vivo-formed with preformed metabolites. trans-3,5,4?-Trihydroxystilbene [trans-resveratrol (RES)] and its two major metabolites, resveratrol-3-sulfate (R3S) and resveratrol-3-glucuronide (R3G) were used as model substrates. The pharmacokinetics (PK) of R3S and R3G were characterized under two situations. First, the pharmacokinetics of R3S and R3G were characterized (in vivo-formed metabolite) after administration of RES. Then, synthetic R3S and R3G were administered (preformed metabolite) and their pharmacokinetics were characterized. PK models were developed to describe the data. A three-compartment model for RES, a two-compartment model for R3S (preformed), and an enterohepatic cycling model for R3G (preformed) was found to describe the data well. These three models were further combined to build a comprehensive PK model, which was used to perform simulations to predict in vivo-formed metabolite kinetics. Comparisons were made between in vivo-formed and preformed metabolite kinetics. Marked differences were observed in the kinetics of preformed and in vivo-formed metabolites.

Sharan, Satish; Iwuchukwu, Otito F.; Canney, Daniel J.; Zimmerman, Cheryl L.

2012-01-01

353

Corrosion Resistance of Nickel Alloys in Manufacturing Ethyl Silicates  

Microsoft Academic Search

lane, and ethyl silicates, because they contain what is called acid spirit, namely alcoholic solutions of hydrogen chloride. In the manufacture of trichlorosilane, an intermediate product is tetraethoxysilane, which is formed by the esterification of silicon tetrachloride by anhydrous ethanol. The reaction involves the sequential replacement of the chlorine linked to silicon by ethoxyl groups. The last stage in the

V. S. Pakhomov; A. G. Parshin

2001-01-01

354

Kinetics of Ethyl Acetate Synthesis Catalyzed by Acidic Resins  

ERIC Educational Resources Information Center

|A low-cost experiment to carry out the second-order reversible reaction of acetic acid esterification with ethanol to produce ethyl acetate is presented to illustrate concepts of kinetics and reactor modeling. The reaction is performed in a batch reactor, and the acetic acid concentration is measured by acid-base titration versus time. The…

Antunes, Bruno M.; Cardoso, Simao P.; Silva, Carlos M.; Portugal, Ines

2011-01-01

355

Sensitivity of Bloom's syndrome lymphocytes to ethyl methanesulfonate  

Microsoft Academic Search

Ethyl methanesulfonate induced several times as many sister chromatid exchanges (SCEs) in lymphocytes from individuals affected with Bloom's syndrome as in lymphocytes from controls or heterozygotes. In cultures of cells from an individual with Bloom's syndrome who had two populations of lymphocytes circulating in his blood—‘low’ cells having normal spontaneous frequencies of SCEs and ‘high’ cells having elevated frequencies—only the

Alena B. Krepinsky; J. A. Heddle; J. German

1979-01-01

356

Glass Transition Temperatures of Poly(ethyl Alpha-Chloroacrylates).  

National Technical Information Service (NTIS)

The glass transition temperatures of stereoregular poly(ethyl alpha-chloroacrylates) have been measured and compared with a previously developed theory. Reasonable consistency was found. A difference of about 300 cal/mol between the Gibbs-DiMarzio flex en...

B. Wesslen F. E. Karasz R. W. Lenz W. R. MacKnight

1970-01-01

357

The synthesis of fatty acid ethyl ester by carboxylester lipase.  

PubMed

Carboxylester lipase obtained from pig pancreas is associated with fatty acid ethyl ester synthase as judged by their elution in the same fraction from a heparin-Sepharose column, coprecipitations by antibody against purified carboxylester lipase and identical profiles of inhibition by diisopropyl fluorophosphate. Only one polypeptide of molecular mass 74-kDa in purified carboxylester lipase was labeled by immunostaining and affinity labeling with [3H]diisopropyl fluorosphate. Bovine serum albumin decreased the fatty-acid-ethyl-ester-synthesizing activity in a concentration-dependent manner. On incubation of purified carboxylester lipase with trioleylglycerol in an ethanol/water mixture, fatty acid ethyl ester was formed in the presence of a high concentration of bovine serum albumin. The acyltransfer activities from trioleylglycerol to ethanol (ethanolysis) were approximately 25-30 times higher than the acyltransfer activities to water (hydrolysis). When cholesterol was used as an acceptor, acyltransfer activity from trioleylglycerol to cholesterol (cholesterolysis) was also observed. We propose the following mechanism of fatty acid ethyl ester formation from triacyl glycerol. The enzyme attacks triacyl glycerol forming an acyl-enzyme intermediate, and during the deacylation process, alcohol binds to fatty acid as an acceptor. These results suggest that during lipid (triacyl glycerol) degradation, carboxylester lipase contributes to non-oxidative ethanol metabolism in the intestinal lumen. PMID:8076651

Tsujita, T; Okuda, H

1994-08-15

358

Complexation of Triclopyr Butoxy Ethyl Ester with ??Cyclodextrin  

Microsoft Academic Search

??cyclodextrin (??CD), a macro?cyclic oligosaccharide exhibits the property of forming inclusion complexes with various molecules. These complexes display some improved properties of starting molecule such as, increase of aqueous solubility, improvement in stability as well as reduction of bad odor and\\/or toxicity of molecules. The formulation of an inclusion complex of ??CD as the host molecule and triclopyr butoxy ethyl

Rahul Vilas Mekade; Manohar Ramchandra Sawant

2006-01-01

359

ELECTRONIC SHIELDING OF THE CRYSTALLINE FIELD IN THULIUM ETHYL SULFATE  

Microsoft Academic Search

The method of recoilless nuclear resonance absorption of gamma radiation ; was employed to investigate the temperature dependence of the nuclear quadrupole ; interaction in the 8.4-kev level of Tm¹⁶⁹ in thulium ethyl sulfate. The ; experiment revealed a strong influence of electronic shielding resulting from the ; polarization induced in the closed electron shells by the crystalline electric ;

R. G. Barnes; E. Kankeleit; R. L. Moessbauer; J. M. Poindexter

1963-01-01

360

Synthesis of Ethyl Nalidixate: A Medicinal Chemistry Experiment  

ERIC Educational Resources Information Center

A series of laboratory experiments that complement a medicinal chemistry lecture course in drug design and development have been developed. The synthesis of ethyl nalidixate covers three separate experimental procedures, all of which can be completed in three, standard three-hour lab classes and incorporate aspects of green chemistry such as…

Leslie, Ray; Leeb, Elaine; Smith, Robert B.

2012-01-01

361

Methyl ethyl ketone exposure in industrial workers uptake and kinetics  

Microsoft Academic Search

Exposure to methyl ethyl ketone (MEK) was studied in workers occupationally exposed in industrial workplaces. Alveolar concentrations of MEK were compared with environmental exposure and with blood MEK concentrations. Urinary excretion of MEK and its metabolite, acetylmethylcarbinol, were compared with environmental exposure. The solubility of MEK was also studied in human body tissues which allowed us to estimate the distribution

L. Perbellini; F. Brugnone; P. Mozzo; V. Cocheo; D. Caretta

1984-01-01

362

Biological monitoring of occupational exposure to methyl ethyl ketone  

Microsoft Academic Search

Summary This study was conducted to evaluate the usefulness of three commonly used methods of biological monitoring for worker exposed to methyl ethyl ketone (MEK) under field conditions using blood, breath and urine. Environmental MEK exposures were measured by personal sampling with carbon-felt dosimeters. The correlation coefficient (r) between the time-weighted average (TWA) MEK concentration in air and the MEK

C. N. Ong; G. L. Sia; H. Y. Ong; W. H. Phoon; K. T. Tan

1991-01-01

363

Environmental and biological monitoring of methyl ethyl ketone (MEK)  

Microsoft Academic Search

This study was conducted to evaluate the usefulness of various biological parameters for monitoring of workers exposed to methyl ethyl ketone (MEK). Fifty male workers from a large magnetic videotape factory participated in this study. Personal air samples were collected using 3M organic vapor monitors and analysed for MEK by gas chromatography with flame ionisation detector (FID). 10 mL of

G. L. Sia; C. N. Ong; S. E. Chia; H. Y. Ong; W. H. Phoon; K. T. Tan

1991-01-01

364

Health and environmental-effects profile for methyl ethyl ketone  

SciTech Connect

The Health and Environmental Effects Profile for methyl ethyl ketone was prepared by the Office of Health and Environmental Assessment, Environmental Criteria and Assessment Office, Cincinnati, OH for the Office of Solid Waste and Emergency Response to support listings of hazardous constituents of a wide range of waste streams under Section 3001 of the Resource Conservation and Recovery Act (RCRA) and to provide health-related limits for emergency actions under Section 101 of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA). Both published literature and information obtained from Agency program office files were evaluated as they pertained to potential human health, aquatic life, and environmental effects of hazardous-waste constituents. Quantitative estimates are presented, provided sufficient data are available. Methyl ethyl ketone has been determined to be a systemic toxicant. An Acceptable Daily Intake (ADI), defined as the amount of a chemical to which humans can be exposed on a daily basis over an extended period of time (usually a lifetime) without suffering a deleterious effect, for methyl ethyl ketone is 3.2 mg/day for oral exposure. The Reportable Quantity (RQ) value of 1, 10, 100, 1000, or 5000 pounds is used to determine the quantity of a hazardous substance for which notification is required in the event of a release as specified by CERCLA based on chronic toxicity. The RQ value for methyl ethyl ketone is 1000.

Not Available

1985-09-01

365

Synthesis and degradation behavior of poly(ethyl cyanoacrylate)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Poly(ethyl cyanoacrylate) was synthesized using N, N'-dimethyl-p-toulidine (DMPT) as an initiator through anionic/zwitterionic pathway. The degradability and the degradation mechanism of the prepared polymers were carefully examined from various points of views. It was found that the polymers were...

366

Health-based recommended occupational exposure limits for ethyl acrylate  

Microsoft Academic Search

The experimental no effect level was 20 mg ethyl acrylate\\/m3. The exposure with slight effects was at 100 mg\\/m3. The real no effect level is between 20 and 100 mg\\/m3. Therefore an occupational exposure limit of 20 mg eth-acr\\/m3 TWA 8 hr is advised with \\

M. A. Maclaine Pont

1990-01-01

367

SELETIVIDADE DE CARFENTRAZONE-ETHYL AOS MILHOS DOCE E NORMAL  

Microsoft Academic Search

RESUMO - Com o objetivo de avaliar a seletividade de carfentrazone-ethyl, herbicida pós- emergente com ação de inibição da enzima protoporfirinogeneo oxidase (PROTOX), sobre cultivares de milho normal e doce, foram instalados experimentos sob condições de casa de vegetação, na Embrapa Milho e Sorgo, em Sete Lagoas, MG. Os experimentos foram dis- postos em blocos casualizados, com quatro repetições. Foram

DÉCIO KARAM; JOSÉ FRANCISCO R. LARA; PAULO CÉSAR MAGALHÃES; ISRAEL ALEXANDRE; PEREIRA FILHO; MICHELLE B. CRUZ

368

40 CFR 63.61 - Deletion of methyl ethyl ketone from the list of hazardous air pollutants.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Deletion of methyl ethyl ketone from the list of hazardous...List § 63.61 Deletion of methyl ethyl ketone from the list of hazardous air pollutants. The substance methyl ethyl ketone (MEK,...

2010-07-01

369

40 CFR 63.61 - Deletion of methyl ethyl ketone from the list of hazardous air pollutants.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Deletion of methyl ethyl ketone from the list of hazardous...List § 63.61 Deletion of methyl ethyl ketone from the list of hazardous air pollutants. The substance methyl ethyl ketone (MEK,...

2013-07-01

370

40 CFR 63.61 - Deletion of methyl ethyl ketone from the list of hazardous air pollutants.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 false Deletion of methyl ethyl ketone from the list of hazardous...List § 63.61 Deletion of methyl ethyl ketone from the list of hazardous air pollutants. The substance methyl ethyl ketone (MEK,...

2009-07-01

371

40 CFR 721.10110 - Hexanoic acid, 2-ethyl-, mixed diesters with benzoic acid and neopentlyl glycol.  

Code of Federal Regulations, 2010 CFR

...2-ethyl-, mixed diesters with benzoic acid and neopentlyl glycol. 721...2-ethyl-, mixed diesters with benzoic acid and neopentlyl glycol. (a...2-ethyl-, mixed diesters with benzoic acid and neopentlyl glycol...

2009-07-01

372

40 CFR 721.10110 - Hexanoic acid, 2-ethyl-, mixed diesters with benzoic acid and neopentlyl glycol.  

Code of Federal Regulations, 2010 CFR

...2-ethyl-, mixed diesters with benzoic acid and neopentlyl glycol. 721...2-ethyl-, mixed diesters with benzoic acid and neopentlyl glycol. (a...2-ethyl-, mixed diesters with benzoic acid and neopentlyl glycol...

2010-07-01

373

40 CFR 721.10111 - Hexanoic acid, 2-ethyl-, mixed diesters with benzoic acid and diethylene glycol.  

Code of Federal Regulations, 2010 CFR

...2-ethyl-, mixed diesters with benzoic acid and diethylene glycol. 721...2-ethyl-, mixed diesters with benzoic acid and diethylene glycol. (a...2-ethyl-, mixed diesters with benzoic acid and diethylene glycol...

2009-07-01

374

40 CFR 721.10111 - Hexanoic acid, 2-ethyl-, mixed diesters with benzoic acid and diethylene glycol.  

Code of Federal Regulations, 2010 CFR

...2-ethyl-, mixed diesters with benzoic acid and diethylene glycol. 721...2-ethyl-, mixed diesters with benzoic acid and diethylene glycol. (a...2-ethyl-, mixed diesters with benzoic acid and diethylene glycol...

2010-07-01

375

40 CFR 721.10109 - Hexanoic acid, 2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Hexanoic acid, 2-ethyl-, mixed triesters with benzoic acid and trimethylolpropane. 721.10109 Section...Chemical Substances § 721.10109 Hexanoic acid, 2-ethyl-, mixed triesters with...

2013-07-01

376

40 CFR 180.662 - Trinexapac-ethyl; tolerances for residues.  

Code of Federal Regulations, 2013 CFR

... Trinexapac-ethyl; tolerances for residues. (a) General. Tolerances are established for residues of the plant growth inhibitor, trinexapac-ethyl, including its metabolites and degradates, in or on the commodities in the...

2013-07-01

377

40 CFR 721.9514 - Ethyl silicate, reaction products with modified alkoxysilane salt (generic).  

Code of Federal Regulations, 2013 CFR

...New Uses for Specific Chemical Substances § 721.9514 Ethyl silicate, reaction products with modified...generic). (a) Chemical substance and significant...reporting. (1) The chemical substance identified...as Ethyl silicate, reaction products with...

2013-07-01

378

40 CFR 180.662 - Trinexapac-ethyl; tolerances for residues.  

Code of Federal Regulations, 2012 CFR

... Trinexapac-ethyl; tolerances for residues. (a) General. Tolerances are established for residues of the plant growth inhibitor, trinexapac-ethyl, including its metabolites and degradates, in or on the commodities in the...

2012-07-01

379

Efficient synthesis of tetrasubstituted thiophenes by reaction of benzoyl isothiocyanates, ethyl bromopyruvate and enaminones  

Microsoft Academic Search

An efficient synthesis of ethyl 2-(4-acetyl-5-benzoylamino-3-methyl-2-thienyl)-2-oxoacetates is described via reaction between benzoyl isothiocyanates and ethyl bromopyruvate in the presence of enaminones.

Issa Yavari; Zinatossadat Hossaini; Maryam Sabbaghan

2008-01-01

380

40 CFR 180.595 - Flufenpyr-ethyl; tolerances for residues.  

Code of Federal Regulations, 2013 CFR

...General. (1) Tolerances are established for residues of the herbicide, flufenpyr-ethyl; acetic acid, [2-chloro-4-fluoro-5...01 (2) Tolerances are established for residues of the herbicide flufenpyr-ethyl; acetic acid,...

2013-07-01

381

40 CFR 180.430 - Fenoxaprop-ethyl; tolerances for residues.  

Code of Federal Regulations, 2013 CFR

...General. Tolerances are established for residues of the herbicide fenoxaprop-ethyl, including its metabolites and...Time-limited tolerances are established for residues of the herbicide fenoxaprop-ethyl, including its...

2013-07-01

382

Insights into the ethyl lactate + water mixed solvent.  

PubMed

The mixed green solvent ethyl lactate + water is studied from macro- and microscopic viewpoints using a wide collection of experimental and computational tools. High-pressure thermophysical data, density, and dynamic viscosity provide valuable information on the macroscopic behavior of the mixed fluid, which is of remarkable importance for industrial purposes, and through the analysis of the derived excess and mixing properties lead to relationships with molecular level properties. Large deviations from ideality are obtained, which are related to the development of strong intermolecular hydrogen bonding between both molecules upon mixing. Computational studies, using the density functional theory, both in gas phase and water solution, allow to characterize, from energetic and structural viewpoints, the different ethyl lactate/water association complexes. The use of atoms in a molecule and natural bond orbital methods sheds light into the properties of ethyl lactate/water hydrogen bonding. Classical molecular dynamics simulations are carried out for the whole composition range, and as a function of pressure and temperature. Force field validation is done by comparison of predicted thermophysical properties with measured ones. Structural features are inferred from the analysis of radial distribution functions and their evolution with composition, pressure, and temperature, and dynamic aspects are inferred from the calculated self-diffusion constants and mean square displacements. The whole study points to a highly structured fluid, in which hydrogen bonding is developed both for water-rich and ethyl-lactate-rich solvents, showing a remarkable effect in the fluid structure upon the addition of the second component for both pure compounds, even more important for the effect of ethyl lactate on water hydrogen bonding network. PMID:19803527

Aparicio, Santiago; Alcalde, Rafael

2009-10-29

383

Infrared spectroscopic studies of the conformation in ethyl ?-haloacetates in the vapor, liquid and solid phases  

Microsoft Academic Search

Infrared spectra of ethyl ?-fluoroacetate, ethyl ?-chloroacetate, ethyl ?-bromoacetate and ethyl ?-iodoacetate have been measured in the solid, liquid and vapor phases in the region 4000–200cm?1. Vibrational frequency assignment of the observed bands to the appropriate modes of vibration was made. Calculations at DFT B3LYP\\/6-311+G** level, Job: conformer distribution, using Spartan program ‘08, release 132 was made to determine which

Naserallah A. Jassem; Muhsin F. El-Bermani

2010-01-01

384

Red blood cell fatty acid ethyl esters: a significant component of fatty acid ethyl esters in the blood  

Microsoft Academic Search

Although alcohol abuse is known to cause an ar- ray of ethanol-induced red blood cell (RBC) abnormalities, the underlying molecular mechanisms remain poorly under- stood. Fatty acid ethyl esters (FAEEs) are toxic, nonoxida- tive ethanol metabolites that have been found in blood, plasma, and tissues. Because FAEEs have been shown to be incorporated into phospholipid bilayers, we conducted a controlled

Catherine A. Best; Joanne E. Cluette-Brown; Miho Teruya; Ami Teruya; Michael Laposata

2003-01-01

385

Biological monitoring of occupational exposure to methyl ethyl ketone by means of urinalysis for methyl ethyl ketone itself  

Microsoft Academic Search

Head space gas chromatography (GC) was applied to measure methyl ethyl ketone (MEK) in urine from 62 MEK-exposed male workers, whose individual intensity of exposure to MEK was monitored utilizing the carbon felt dosimeter. The urinary MEK level increased rapidly to reach a plateau in the first quarter of the daily 8-h work, while very little MEK was detected in

Michiko Miyasaka; Miho Kumai; Akio Koizumi; Takao Watanabe; Kazuyuki Kurasako; Kunihiko Sato; Masayuki Ikeda

1982-01-01

386

Determination of ethyl carbamate in some fermented Korean foods and beverages  

Microsoft Academic Search

Ethyl carbamate has been associated with cancer for several decades. It is mainly found in fermented foods and beverages. In view of the importance of fermented foods in the Korean diet and the significant level of ethyl carbamate expected, we determined ethyl carbamate concentrations in some of the staple food items and estimated the daily intake for the Korean population.

Young-Kyunge Le Kim; Eunmi Koh; Hyun-Jung Chung; Hoonjeong Kwon

2000-01-01

387

Effects of ?-glutamylcysteine ethyl ester on heart mitochondrial creatine kinase activity: involvement of sulfhydryl groups  

Microsoft Academic Search

To study the mechanism of the protective effect of ?-glutamylcysteine ethyl ester, mitochondrial creatine kinase activity of rat heart was measured. ?-Glutamylcysteine ethyl ester had a protective effect against the depression of creatine kinase activity induced by xanthine+xanthine oxidase or hydrogen peroxide. ?-Glutamylcysteine ethyl ester also prevented the depression of creatine kinase activity induced by N-ethylmaleimide. It is suggested that

Hideharu Hayashi; Masaru Iimuro; Yuji Matsumoto; Masanori Kaneko

1998-01-01

388

Enzymatic synthesis of glycerides from DHA-enriched PUFA ethyl ester by glycerolysis under vacuum  

Microsoft Academic Search

Pseudomonas lipase immobilized on CaCO3 powder was used for the glycerolysis of n?3 polyunsaturated fatty acid ethyl esters to prepare nutritionally valuable glycerides. The initial ethyl ester contained 65 or 99% docosahexaenoic acid ethyl ester (DHAEE) which is very unstable and readily oxidized. The process performance was intensified by: (1) using Pseudomonas lipase which has good specificity for docosahexaenoic acid

Roxana Rosu; Yugo Iwasaki; Nobuyoshi Shimidzu; Nobushige Doisaki; Tsuneo Yamane

1998-01-01

389

75 FR 82069 - Ethyl Alcohol for Fuel Use: Determination of the Base Quantity of Imports  

Federal Register 2010, 2011, 2012, 2013

...Investigation No. 332-288] Ethyl Alcohol for Fuel Use: Determination of the Base Quantity of Imports...quantity'' of imports of fuel ethyl alcohol with a zero percent local...level of U.S. consumption of fuel ethyl alcohol to be 12.506 billion...

2010-12-29

390

Genotoxicity of ethyl carbamate (urethane) in Salmonella, yeast and human lymphoblastoid cells  

Microsoft Academic Search

Ethyl carbamate is a known carcinogen occurring in fermented food and beverages and is therefore of interest for food safety assurance. We studied the genotoxicity of ethyl carbamate in Salmonella typhimurium, in Saccharomyces cerevisiae and in human lymphoblastoid TK6 cells. In absence of cytochrome P450 enzymes, no ethyl carbamate-mediated genotoxicity was observed in any of the three test systems in

Philipp Hübner; Philippe M Groux; Beatrice Weibel; Christian Sengstag; Janine Horlbeck; Phaik-Mooi Leong-Morgenthaler; Jürg Lüthy

1997-01-01

391

40 CFR 721.4250 - Hexanoic acid, 2-ethyl-, ethenyl ester.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Hexanoic acid, 2-ethyl-, ethenyl ester...Substances § 721.4250 Hexanoic acid, 2-ethyl-, ethenyl ester...substance identified as hexanoic acid, 2-ethyl-, ethenyl...Standard Test Method for Resistance of Protective Clothing...

2010-07-01

392

40 CFR 721.4250 - Hexanoic acid, 2-ethyl-, ethenyl ester.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 false Hexanoic acid, 2-ethyl-, ethenyl ester...Substances § 721.4250 Hexanoic acid, 2-ethyl-, ethenyl ester...substance identified as hexanoic acid, 2-ethyl-, ethenyl...Standard Test Method for Resistance of Protective Clothing...

2009-07-01

393

The pharmacokinetics of morphine and morphine glucuronide metabolites after subcutaneous bolus injection and subcutaneous infusion of morphine  

PubMed Central

Aims To investigate the pharmacokinetics of morphine, morphine-6-glucuronide (M6G) and morphine-3-glucuronide (M3G) in healthy volunteers after the administration of morphine by subcutaneous bolus injection (s.c.b.) and subcutaneous infusion (s.c.i.) over 4 h, and to compare the results with the intravenous bolus (i.v.) administration of morphine. Methods Six healthy volunteers each received 5 mg morphine sulphate by i.v., s.c.b. and short s.c.i. over 4 h, on three separate occasions, in random order, each separated by at least 1 week. Plasma samples were assayed for morphine, M6G and M3G. Results After i.v. morphine, the concentrations of morphine, M6G and M3G and their pharmacokinetic parameters were similar to those we have observed previously, in other healthy volunteers (when standardized to nmol l?1, for a 10 mg dose to a 70 kg subject). After s.c.b. morphine, similar results were obtained except that the median tmax values for morphine and M3G were significantly longer than after i.v. morphine (P < 0.001 and P < 0.05, respectively), with a trend to a longer tmax for M6G (P = 0.09). The appearance half-lives after s.c.b. morphine for M6G and M3G were also significantly longer than after i.v. morphine (P = 0.03 and P < 0.05, respectively). Comparison of log-transformed AUC values indicated that i.v. and s.c.b. administration of morphine were bioequivalent with respect to morphine, M6G and M3G. In comparison with i.v. morphine, morphine by s.c.i. was associated with significantly longer median tmax values for morphine (P < 0.001), M6G (P < 0.001) and M3G (P < 0.05), and the mean standardized Cmax values significantly lower than after both i.v. and s.c.b. morphine (morphine P < 0.001, M6G P < 0.001 and M3G P < 0.01 for each comparison). Comparison of log-transformed AUC values after i.v. and s.c.i. morphine indicated that the two routes were not bioequivalent for morphine (log-transformed AUC ratio 0.78, 90% CI 0.66–0.93), M6G (0.72, 90% CI 0.63–0.82), or M3G (0.65, 90% CI 0.54–0.78). A small stability study indicated no evidence of adsorptive losses from morphine infused over 4 h using the infusion devices from the study. Conclusions Although bioequivalence was demonstrated between the s.c.b. and i.v. routes of morphine administration, the bioavailabilities of morphine, M6G and M3G after s.c.i. were significantly lower than after i.v. administration. However, despite this, the study demonstrates that the subcutaneous route is an effective method for the parenteral administration of morphine.

Stuart-harris, R; Joel, S P; McDonald, P; Currow, D; Slevin, M L

2000-01-01

394

Development of an enzyme immunoassay for urinary pregnanediol-3-glucuronide in a female giant panda (Ailuropoda melanoleuca).  

PubMed

In order to enable monitoring of the reproductive status of the female giant panda after observation of estrus behavior, we developed an enzyme immunoassay (EIA) system for urinary pregnanediol-3-glucuronide (PdG), a progesterone metabolite, using commercial reagents and examined the changes in the urinary concentration of PdG in a female giant panda that showed pseudopregnancy and suspicious pseudopregnancy in 6 consecutive years. The developed EIA system had good reproducibility (intra- and interassay CVs 6.1% and 16.3%, respectively), good parallelism between the standard curve and the dose response curve of serial diluted samples and positive correlation (r=0.836) with the data for PdG in the same samples measured by gas chromatography. Urinary PdG in the female panda showed two phases of increase. The first elevation was observed immediately after estrus with the levels of PdG below 100 ng/Crmg, while the second phase was characterized by a drastic elevation above 100 ng/Crmg until the level began to decrease at the end of pseudopregnancy or suspicious pseudopregnancy. The length of the second phase had wider range than that of the first phase. In the present study, a new EIA assay system for urinary PdG in the female giant panda was developed, and we found that the length of the second phase is unstable in the pseudopregnant and suspicious pseudopregnant giant panda, in contrast with the unstable length of the first phase caused by delayed implantation in the pregnant giant panda. PMID:19652473

Hama, Natsuki; Kanemitsu, Hideyasu; Tanikawa, Michiyo; Shibaya, Masami; Sakamoto, Kensuke; Oyama, Yujiro; Acosta, Tomas J; Ishikawa, Osamu; Pengyan, Wang; Okuda, Kiyoshi

2009-07-01

395

Rapid deconjugation of SN-38 glucuronide and adsorption of released free SN-38 by intestinal microorganisms in rat  

PubMed Central

One of the dose-limiting toxicities of irinotecan hydrochloride (CPT-11) is delayed-onset diarrhea. CPT-11 is converted to its active metabolite, SN-38, which is conjugated to SN-38 glucuronide (SN-38G). SN-38G excreted in the intestinal lumen is extensively deconjugated by bacterial ?-glucuronidase, resulting in the regeneration of SN-38, which causes diarrhea. However, the deconjugation of SN-38G by the intestinal microflora remains to be clarified. This study aimed to investigate the microbial transformation of SN-38G by an anaerobic mixed culture of rat cecal microorganisms. Concentrations of SN-38G and SN-38 were then determined using high-performance liquid chromatography. Complete deconjugation of SN-38G to SN-38 in the mixed cultures was observed within 1 h of incubation, with 62.7% of the added SN-38G being found in the supernatant. Approximately 80.4% of the SN-38 in the supernatant was bound to protein, and the remaining 19.6% was detected as active free SN-38. In total, only 12.3% (19.6 × 62.7%) of the SN-38G added to the test tube was found in the supernatant in the ultrafiltrable free form, indicating that approximately 90% of the SN-38G added to the growth medium either remained adsorbed onto the pelleted fraction or occurred in a protein-bound form in the supernatant. The remaining 10% of the SN-38G added to the growth medium existed in the unbound form, the form capable of causing damage to the intestinal membrane. In conclusion, these results indicated that the greater part of the SN-38 produced from SN-38G by the action of bacterial ?-glucuronidase is rapidly adsorbed onto intestinal bacterial cell walls or dietary fibers in pelleted fraction, and only 10% remains in the ultrafiltrable unbound form in the intestinal luminal fluid.

TAKAKURA, AKIRA; KURITA, AKINOBU; ASAHARA, TAKASHI; YOKOBA, MASANORI; YAMAMOTO, MICHIKO; RYUGE, SHINICHIRO; IGAWA, SATOSHI; YASUZAWA, YUKITOSHI; SASAKI, JIICHIRO; KOBAYASHI, HIROSUKE; MASUDA, NORIYUKI

2011-01-01

396

Usefulness of early morning urine estrone-3-glucuronide assay in the monitoring ovarian secretory function in precocious puberty.  

PubMed

To evaluate the usefulness of the urinary estrone-3-glucuronide (EI-3-G) in the monitoring of the ovarian function in girls, we studied 11 girls with idiopathic central precocious puberty (ICPP) treated with LHRH analogs (LHRHa) for 2-5 years. Plasma LH, FSH, 17-beta-Estradiol (E2) levels, early morning urine (EMU) E1-3-G concentrations, were assessed before and 3, 6, 12 months after the onset of treatment. As expected, mean basal plasma LH, FSH and E2 concentrations, as well as mean basal EMU E1-3-G levels were significantly (p < 0.01) higher in patients studied than in normal, age matched, prepubertal controls. Three out of the 11 sexually advanced girls showed undetectable (< 15 pg/ml) basal plasma E2 values. On the contrary, in each patient studied, individual basal E1-3-G levels were higher than in normal age-matched prepubertal girls. LHRHa treatment significantly suppressed both basal and peak stimulated plasma gonadotropins, plasma E2 and EMU E1-3-G. However, while serum E2 levels were below the assay detection limit, not allowing to assess the degree of gonadal suppression, E1-3-G urinary concentrations were detectable in each subject treated, in the range of the normal prepubertal values. EMU E1-3-G determination seems to be a very sensitive and reliable approach to the monitoring of the effectiveness of LHRHa treatment in sexually advanced girls, allowing to detect very low estrogen concentrations and to achieve the desired ovarian suppression. PMID:7629394

Bassi, F; Bartolini, O; Neri, A S; Gheri, R G; Magini, A; Bucciantini, S; Bruni, V

1995-02-01

397

Altered hepatobiliary disposition of acetaminophen glucuronide in isolated perfused livers from multidrug resistance-associated protein 2-deficient TR(-) rats.  

PubMed

Previous studies have demonstrated that phenobarbital treatment impairs the biliary excretion of acetaminophen glucuronide (AG), although the transport system(s) responsible for AG excretion into bile has not been identified. Initial studies in rat canalicular liver plasma membrane vesicles indicated that AG uptake was stimulated modestly by ATP, but not by membrane potential, HCO(3)(-), or pH gradients. To examine the role of the ATP-dependent canalicular transporter multidrug resistance-associated protein 2 (Mrp2)/canalicular multispecific organic anion transporter (cMOAT) in the biliary excretion of AG, the hepatobiliary disposition of acetaminophen, AG, and acetaminophen sulfate (AS) was examined in isolated perfused livers from control and TR(-) (Mrp2-deficient) Wistar rats. Mean bile flow in TR(-) livers was approximately 0.3 microl/min/g of liver ( approximately 4-fold lower than control). AG biliary excretion was decreased (>300-fold) to negligible levels in TR(-) rat livers, indicating that AG is an Mrp2 substrate. Similarly, AS biliary excretion in TR(-) livers was decreased ( approximately 5-fold); however, concentrations were still measurable, suggesting that multiple mechanisms, including Mrp2-mediated active transport, may be involved in AS biliary excretion. AG and AS perfusate concentrations were significantly higher in livers from TR(-) compared with control rats. Pharmacokinetic modeling of the data revealed that the rate constant for basolateral egress of AG increased significantly from 0.028 to 0.206 min(-1), consistent with up-regulation of a basolateral organic anion transporter in Mrp2-deficient rat livers. In conclusion, these data indicate that AG biliary excretion is mediated by Mrp2, and clearly demonstrate that substrate disposition may be influenced by alterations in complementary transport systems in transport-deficient animals. PMID:11046083

Xiong, H; Turner, K C; Ward, E S; Jansen, P L; Brouwer, K L

2000-11-01

398

Hydroxylated polychlorinated biphenyls as inhibitors of the sulfation and glucuronidation of 3-hydroxy-benzo[a]pyrene.  

PubMed Central

Polychlorinated biphenyls (PCBs) can be metabolized by cytochromes P450 to hydroxylated biotransformation products. In mammalian studies, some of the hydroxylated products have been shown to be strong inhibitors of steroid sulfotransferases. As a part of ongoing research into the bioavailability of environmental pollutants in catfish intestine, we investigated the effects of a series of hydroxylated PCBs (OH-PCBs) on two conjugating enzymes, phenol-type sulfotransferase and glucuronosyltransferase. We incubated cytosolic and microsomal samples prepared from intestinal mucosa with 3-hydroxy-benzo[a]pyrene and appropriate cosubstrates and measured the effect of OH-PCBs on the formation of BaP-3-glucuronide and BaP-3-sulfate. We used PCBs with 4, 5, and 6 chlorine substitutions and the phenolic group in the ortho, meta, and para positions. OH-PCBs with the phenolic group in the ortho position were weak inhibitors of sulfotransferase; the median inhibitory concentration (IC50) ranged from 330 to 526 microM. When the phenol group was in the meta or para position, the IC50 was much lower (17.8-44.3 microM). The OH-PCBs were more potent inhibitors of glucuronosyltransferase, with IC50s ranging from 1.2 to 36.4 microM. The position of the phenolic group was not related to the inhibitory potency: the two weakest inhibitors of sulfotransferase, with the phenolic group in the ortho position, were 100 times more potent as inhibitors of glucuronosyltransferase. Inhibition of glucuronosyltransferase by low concentrations of OH-PCBs has not been reported before and may have important consequences for the bioavailability, bioaccumulation, and toxicity of other phenolic environmental contaminants.

van den Hurk, Peter; Kubiczak, Gerhard A; Lehmler, Hans-Joachim; James, Margaret O

2002-01-01

399

Proteins identified as targets of the acyl glucuronide metabolite of mycophenolic acid in kidney tissue from mycophenolate mofetil treated rats.  

PubMed

Covalent binding of the acyl glucuronide (AcMPAG) metabolite of the immunosuppressant mycophenolic acid (MPA) to proteins is considered a possible initiating event for organ toxicity. Since the kidney is involved in the formation and excretion of AcMPAG, it can be hypothesized that this tissue may be exposed to relatively high concentrations of this metabolite and would, therefore, be a particularly suitable organ to investigate AcMPAG protein targets. In the present study we identified potential AcMPAG target proteins in kidney tissues from Wistar rats treated with mycophenolate mofetil (40 mg/kg/day over 21 days). Proteins were separated by 2-DE and covalent protein adducts were detected by Western blotting with an antibody specific for MPA/AcMPAG. The corresponding coomassie blue stained proteins from parallel gels were subjected to in-gel tryptic digestion and peptides were characterized on a Q-TOF Ultima Global. The protein targets were further verified by immunoprecipitation with anti-MPA/AcMPAG antibody to purify the modified proteins followed by 1-DE and MS analysis. Database searches revealed several AcMPAG target proteins that could be related to ultrastructural abnormalities, metabolic effects, and altered oxidative stress/detoxification responses. Predominately cytosolic proteins such as selenium binding protein, protein disulfide isomerase, aldehyde dehydrogenase, triosephosphate isomerase, and kidney aminoacylase were involved in adduct formation. Two cytoskeletal proteins tropomyosin 1 and 4 as well as the antioxidant proteins peroxiredoxin 3 and 6 were also targets of AcMPAG. Functional consequences from these protein modifications remain to be demonstrated. PMID:17069946

Asif, Abdul R; Armstrong, Victor W; Voland, Antje; Wieland, Eberhard; Oellerich, Michael; Shipkova, Maria

2006-10-16

400

Impact of anti-cancer drugs and other determinants on serum protein binding of morphine 6-glucuronide  

PubMed Central

Background and the purpose of the study The aim of the present study was to examine factors that may influence the protein binding of morphine 6-glucuronide (M6G), the most active metabolite of morphine. Methods An enzyme-linked immunoabsorbent assay technique was used to measure the M6G concentration in serum of 18 healthy adults, 18 neonatal and 7 children with cancer. Total and free M6G concentrations were measured following equilibrium dialysis for 3 hrs and at physiological pH at 37°C. The influence of vincristine, methotrexate, 6-mercaptopurine, morphine, human albumin, alpha-1-acid glycoprotein, palmitic acid, oleic acid and pH on M6G protein binding was examined. Results M6G was 66.87±0.73 percent free in human serum at physiological pH and temperature. The percentage free (unbound) was increased significantly by vincristine (4.33%) and methotrexate (9.68%), but 6- mercaptopurine and morphine had no significant effect on it. Free percentages of M6G was reduced by decreasing serum albumin concentration but was unaffected by the presence of alpa-1-acid glycoprotein (AAG) or changes in serum pH. Similar results were obtained in human serum albumin (HAS) solutions. Addition of palmitic acid and oleic acid reduced protein binding significantly by 6.3% and 7.4%, respectively. Major conclusion Although M6G in this study was not highly bounded, but because of its high analgesic potency, any change in its free concentration due to concurrent medication or disease caused significant changes in its effects. This dearth of evidence has been implicated in the reluctance of professionals to be cautious in prescribing them to children, particularly in the neonatal period.

Mashayekhi, S.O.; Ghandforoush-Sattari, M.; Buss, D.C.; Routledge, P.A.; Hain, R.DW.

2010-01-01

401

Glucuronidation and sulfonation, in vitro, of the major endocrine-active metabolites of methoxychlor in the channel catfish, Ictalurus punctatus, and induction following treatment with 3-methylcholanthrene  

PubMed Central

The organochlorine pesticide, methoxychlor (MXC), is metabolized in animals to phenolic mono- and bis-demethylated metabolites (OH-MXC and HPTE respectively) that interact with estrogen receptors and may be endocrine disruptors. The phase II detoxication of these compounds will influence the duration of action of the estrogenic metabolites, but has not been investigated extensively. In this study, the glucuronidation and sulfonation of OH-MXC and HPTE were investigated in subcellular fractions of liver and intestine from untreated, MXC-treated and 3-methylcholanthrene (3-MC)-treated channel catfish, Ictalurus punctatus. MXC-treated fish were given i.p. injections of 2 mg MXC/kg daily for 6 days and sacrificed 24 hr after the last dose. The 3-MC treatment was a single 10 mg/kg i.p. dose 5 days prior to sacrifice. In hepatic microsomes from control fish, the Vmax value (mean ± S.D., n=4) for glucuronidation of OH-MXC was 270 ± 50 pmol/min/mg protein, higher than found for HPTE (110 ± 20 pmol/min/mg protein). For each substrate, the Vmax values observed in intestinal microsomes were approximately twice those found in the liver. The Km values for OH-MXC and HPTE glucuronidation in control liver were not significantly different and were 0.32 ± 0.04 mM for OH-MXC and 0.26 ± 0.06 mM for HPTE. The Km for the co-substrate, UDPGA, was higher in liver (0.28 ± 0.09 mM) than intestine (0.04 ± 0.02 mM). Treatment with 3-MC but not MXC increased the Vmax for glucuronidation in liver and intestine. Glucuronidation was a more efficient pathway than sulfonation for both substrates, in both tissues. The Vmax values for sulfonation of OH-MXC and HPTE respectively in liver cytosol were 7 ± 3 and 17 ± 4 pmol/min/mg protein and in intestinal cytosol were 13 ± 3 and 30 ± 5 pmol/min/mg protein. Treatment with 3-MC but not MXC increased rates of sulfonation of OH-MXC and HPTE and the model substrate, 3-hydroxy-benzo(a)pyrene in both intestine and liver. Comparison of the kinetics of the conjugation pathways with those published for the demethylation of MXC showed that formation of the endocrine-active metabolites was more efficient than either conjugation pathway. Residues of OH-MXC and HPTE were detected in extracts of liver microsomes from MXC-treated fish. This work showed that although OH-MXC and HPTE could be eliminated by glucuronidation and sulfonation, the phase II pathways were less efficient than the phase I pathway leading to formation of these endocrine-active metabolites.

James, Margaret O.; Stuchal, Leah D.; Nyagode, Beatrice A.

2008-01-01

402

Plasma stability-dependent circulation of acyl glucuronide metabolites in humans: how circulating metabolite profiles of muraglitazar and peliglitazar can lead to misleading risk assessment.  

PubMed

Muraglitazar and peliglitazar, two structural analogs differing by a methyl group, are dual peroxisome proliferator-activated receptor-?/? activators. Both compounds were extensively metabolized in humans through acyl glucuronidation to form 1-O-?-acyl glucuronide (AG) metabolites as the major drug-related components in bile, representing at least 15 to 16% of the dose after oral administration. Peliglitazar AG was the major circulating metabolite, whereas muraglitazar AG was a very minor circulating metabolite in humans. Peliglitazar AG circulated at lower concentrations in animal species than in humans. Both compounds had a similar glucuronidation rate in UDP-glucuronic acid-fortified human liver microsomal incubations and a similar metabolism rate in human hepatocytes. Muraglitazar AG and peliglitazar AG were chemically synthesized and found to be similarly oxidized through hydroxylation and O-demethylation in NADPH-fortified human liver microsomal incubations. Peliglitazar AG had a greater stability than muraglitazar AG in incubations in buffer, rat, or human plasma (pH 7.4). Incubations of muraglitazar AG or peliglitazar AG in plasma produced more aglycon than acyl migration products compared with incubations in the buffer. These data suggested that the difference in plasma stability, not differences in intrinsic formation, direct excretion, or further oxidation of muraglitazar AG or peliglitazar AG, contributed to the observed difference in the circulation of these AG metabolites in humans. The study demonstrated the difficulty in doing risk assessment based on metabolite exposure in plasma because the more reactive muraglitazar AG would not have triggered a threshold of concern based on the recent U.S. Food and Drug Administration guidance on Metabolites in Safety Testing, whereas the more stable peliglitazar AG would have. PMID:20876787

Zhang, Donglu; Raghavan, Nirmala; Wang, Lifei; Xue, Yongjun; Obermeier, Mary; Chen, Stephanie; Tao, Shiwei; Zhang, Hao; Cheng, Peter T; Li, Wenying; Ramanathan, Ragu; Yang, Zheng; Humphreys, W Griffith

2010-09-28

403

Enzymatic synthesis of (125/131)I labeled 8-hydroxyquinoline glucuronide and in vitro/in vivo evaluation of biological influence.  

PubMed

8-Hydroxyquinoline (8-OHQ) is a long-known molecule which due to its metal-complexation ability is frequently used for analysis. It is also called oxine. Oxine and derivatives have been investigated to process antitumor and antimicrobial activities. 8-Hydroxyquinolyl-glucuronide (8-OHQ-Glu) was enzymatically synthesized using microsome preparates separated from Hutu-80 cells, labeled with (125)I to perform a radionuclide labeled prodrug and investigated of its biological affinities on Hutu-80 (human duodenum intestinal adenocarcinoma), Caco-2 (human colorectal adenocarcinoma), Detroit 562 (human pharynx adenocarcinoma) cells and ACBRI 519 (primary human small intestine epithelial cells) in this work. UDP-glucuronyl transferase (UDPGT) rich microsome preparates, which are used for glucuronidation in enzymatic synthesis, were extracted from Hutu-80 cells. 8-OHQ-Glu components were labeled using iodogen method with (125)I and (131)I. Structural analyses were performed with LC/MS/MS, (1)H NMR and (13)C-MMR for identify and measure chemical constituents. Results confirmed expected molecular structure. 8-OHQ-Glu could successfully radioiodinated with (125/131)I according to iodogen method. (125)I-8-OHQ-glucuronide incorporated with human gastrointestinal cancer cells such as Detroit-562 (human pharynx adenocarcinoma) (12.6%), Caco-2 (human colorectal adenocarcinoma) (7.8%), Hutu- 80 (human duodenum intestinal adenocarcinoma) (9.5%) and ACBRI 519 (primary human small intestine epithelial cells) (6.40%). (131)I-8-OHQ-Glu was tested in mice bearing subcutaneously implanted Caco-2 colorectal adenocarcinoma cells. The results demonstrated that radioiodinated 8-OHQ-Glu may be promising anticancer prodrug. PMID:21109446

Ye?ila?aç, Reyhan; Ünak, Perihan; Medine, E ?lker; ?çhedef, Çi?dem A; Ertay, Turkan; Müftüler, F Z Biber

2010-11-18

404

Pharmacokinetics of liquiritigenin and its two glucuronides, M1 and M2, in rats with acute hepatitis induced by d-galactosamine/lipopolysaccharide or CCl(4).  

PubMed

Cytoprotective effects of liquiritigenin (LQ) against liver injuries have been reported, but its pharmacokinetics has not been studied in acute hepatitis. Thus, pharmacokinetics of LQ and its two conjugated glucuronide metabolites: 4'-O-glucuronide (M1) and 7-O-glucuronide (M2), in rats with acute hepatitis induced by d-galactosamine/lipopolysaccharide (GalN/LPS) rats or carbon tetrachloride-treated (CCl(4)-treated) rats were evaluated. LQ was administered intravenously (20 mg kg(-1)) and orally (50 mg kg(-1)) to control GalN/LPS and CCl(4)-treated rats. Expression of uridine 5'-diphospho-glucuronosyltransferases 1A (UGT1A) and in vitro metabolism of LQ in hepatic and intestinal microsomes were also measured. After intravenous administration of LQ, area under the plasma concentration-time curve (AUC) of LQ in GalN/LPS rats was significantly smaller than that in controls due to faster non-renal clearance, as a result of its greater free fraction in plasma and faster hepatic blood flow rate than the controls. In CCl(4)-treated rats, the AUC(M1, 0-8 h)/AUC(LQ) and AUC(M2, 0-8 h)/AUC(LQ) ratios were significantly greater than the controls due to decrease in biliary excretion of M1 and M2. However, no significant pharmacokinetic changes were observed in both acute hepatitis rats after oral administration due to comparable intestinal metabolism of LQ. Modification of oral dosage regimen of LQ may not be necessary in patients with acute hepatitis; but human studies are required. PMID:20350053

Kang, H E; Kim, Y W; Sohn, S I; Baek, S R; Lee, J W; Kim, S G; Lee, I; Lee, M G

2010-06-01

405

Elevated plasma creatinine due to creatine ethyl ester use.  

PubMed

Creatine is a nutritional supplement widely used in sport, physical fitness training and bodybuilding. It is claimed to enhance performance. We describe a case in which serum creatinine is elevated due to the use of creatine ethyl esther. One week after withdrawal, the plasma creatinine had normalised. There are two types of creatine products available: creatine ethyl esther (CEE) and creatine monohydrate (CM). Plasma creatinine is not elevated in all creatine-using subjects. CEE , but not CM, is converted into creatinine in the gastrointestinal tract. As a result the use of CEE may be associated with elevated plasma creatinine levels. Since plasma creatinine is a widely used marker for renal function, the use of CEE may lead to a false assumption of renal failure. PMID:21411845

Velema, M S; de Ronde, W

2011-02-01

406

Highly efficient palladium-catalyzed hydrostannation of ethyl ethynyl ether  

PubMed Central

The palladium-catalyzed hydrostannation of acetylenes is widely exploited in organic synthesis as a means of forming vinyl stannanes for use in palladium-catalyzed cross-coupling reactions. Application of this methodology to ethyl ethynyl ether results in an enol ether that is challenging to isolate from the crude reaction mixture because of incompatibility with typical silica gel chromatography. Reported here is a highly efficient procedure for the palladium-catalyzed hydrostannation of ethyl ethynyl ether using 0.1% palladium(0) catalyst and 1.0 equiv of tributyltin hydride. The product obtained is a mixture of regioisomers that can be carried forward with exclusive reaction of the ?-isomer. This method is highly reproducible; relative to previously reported procedures, it is more economical and involves a more facile purification procedure.

Andrews, Ian P.; Kwon, Ohyun

2008-01-01

407

Ethyl carbamate levels resulting from azodicarbonamide use in bread  

Microsoft Academic Search

Azodicarbonamide (ADA), a dough conditioner, is an additive approved in the US up to a maximum of 45 mg\\/kg in flour. The addition of 45 mg\\/kg of ADA was investigated and found to increase the ethyl carbamate (EC) content of commercially prepared breads by 1–3 ?g\\/kg. A similar increase in EC was observed in breads baked in the laboratory with

Benjamin J. Cañas; Gregory W. Diachenko; Patricia J. Nyman

1997-01-01

408

Ab Initio Torsion-Wag Surface for the Ethyl Radical  

Microsoft Academic Search

The torsion-wag potential of the ethyl radical has a 6-fold barrier to internal rotation and the minimum energy path involves deviations of the CH2 wag angle of 6 to 11 degrees on either side of planar. Partially optimized 2-dimensional surfaces were calculated at the B3LYP, MP2, and CCSD(T) levels with 6-311++G(d,p) and 6-311++G(3df, 2p) basis sets and they were fit

Ram S. Bhatta; David S. Perry

2009-01-01

409

Peroxidization of methyl ethyl ketone in a microchannel reactor  

Microsoft Academic Search

Methyl ethyl ketone (MEK) peroxidation is carried out in a microchannel reactor under different reaction temperatures, H2O2 and acid concentrations, and feeding rates without using any organic solvent. It is found that at high reaction temperatures the decomposition of the peroxides will be accelerated. Increasing H2O2 concentration will increase the active oxygen content, while increasing H+ concentration will increase the

Wei Wu; Gang Qian; Xing-Gui Zhou; Wei-Kang Yuan

2007-01-01

410

Solubility behavior of ethyl cellulose in supercritical fluid solvents  

Microsoft Academic Search

Solubility data to 180°C and 1200 bar are reported for ?1.0 wt.% ethyl cellulose (50% ethoxyl content, 2.5 average degree of substitution) (EC) in neat supercritical fluid (SCF) chlorodifluoromethane (F22); difluoromethane; 1-chloro-1,1-difluoroethane; 1,1-difluoroethane; and dimethyl ether (DME). The pressures needed to dissolve EC in the polar fluorocarbons decreases with increasing solvent size. The exception in this trend is F22 which

Dan Li; Mark A. McHugh

2004-01-01

411

Enantioselective hydrogenation of ethyl acetoacetate on asymmetric Raney Ni catalysts  

SciTech Connect

The properties of Raney nickel catalysts modified by (+)-tartaric acid and active in enantioselective hydrogenation of ethyl acetoacetate depend on the chemical and phase compositions of the starting Ni-Al alloys. A decrease of the Ni content in the Ni-Al alloy specimens which corresponds to an increase of the fraction of the NiAl/sub 3/ intermetallic compound in them contributes to an increase of the catalytic activity and enantioselectivity of the action of the obtained catalysts.

Zubareva, N.D.; Chernysheva, V.V.; Grigor'ev, Yu.A.; Klabunovskii, E.I.

1987-09-10

412

Electrochemical Copolymerization of Pyrrole and Methyl Ethyl Ketone Formaldehyde Resin  

Microsoft Academic Search

Electrochemical polymerization of pyrrole in the presence of methyl ethyl ketone formaldehyde resin (MEKF-R) was accomplished. Characterization of insoluble free-standing films was carried out via FTIR spectrum, cyclic voltammogram (CV), UV-visible spectrum, and four-point probe conductivity measurements. The effect of pyrrole and the resin concentrations on the conductivity of the resulting products was investigated. The copolymers obtained as free-standing films

Belk?s Ustamehmeto?lu; Nilgün K?z?lcan; A. Sezai Saraç; Ahmet Akar

2005-01-01

413

Effects of acetone on methyl ethyl ketone peroxide runaway reaction  

Microsoft Academic Search

Runaway reactions by methyl ethyl ketone peroxide (MEKPO) are an important issue in Asia, due to its unstable structure and extensive heat release during upset situations. This study employed differential scanning calorimetry (DSC) to draw the experimental data for MEKPO 31mass% and with acetone 99mass% on three types of heating rate of 2, 4, and 10°C\\/min; the kinetic and safety

Yan-Fu Lin; Jo-Ming Tseng; Tsung-Chih Wu; Chi-Min Shu

2008-01-01

414

Successful Topical Dissolution of Cholesterol Gallbladder Stones Using Ethyl Propionate  

Microsoft Academic Search

Topical dissolution of cholesterol gallbladderstones using methyl tert-butyl ether (MTBE) is useful insymptomatic patients judged too ill for surgery.Previous studies showed that ethyl propionate (EP), a C5 ester, dissolves cholesterolgallstones rapidly in vitro, but differs from MTBE inbeing eliminated so rapidly by the liver that bloodlevels remain undetectable. Our aim was to test EP as atopical dissolution agent for cholesterol

Alan F. Hofmann; Andree Amelsberg; Oliver Esch; Claudio D. Schteingart; Kip Lyche; Horacio Jinich; Eric Vansonnenberg; Horacio B. D'Agostino

1997-01-01

415

Interactions between covalently crosslinked ethyl(hydroxyethyl)cellulose and SDS  

Microsoft Academic Search

The equilibrium swelling of chemically crosslinked gels based on ethyl(hydroxyethyl)cellulose (EHEC) in aqueous solutions of sodium dodecyl sulphate (SDS) was studied as a function of the SDS concentration at various temperatures and salt concentrations. Comparisons were made with gels based on poly-N-isopropylacrylamide (p-NIPA). Both polymers are known to form complexes with SDS above a critical association concentration (cac) of the

Olof Rosén; Lennart Piculell

1997-01-01

416

Lipopolysaccharide enhances the cytotoxicity of 2-chloroethyl ethyl sulfide  

Microsoft Academic Search

BACKGROUND: The bacterial endotoxin, lipopolysaccharide (LPS), is a well-characterized inflammatory factor found in the cell wall of Gram-negative bacteria. In this investigation, we studied the cytotoxic interaction between 2-chloroethyl ethyl sulfide (CEES or ClCH2CH2SCH2CH3) and LPS using murine RAW264.7 macrophages. CEES is a sulfur vesicating agent and is an analog of 2,2'-dichlorodiethyl sulfide (sulfur mustard). LPS is a ubiquitous natural

William L Stone; Min Qui; Milton Smith

2003-01-01

417

Microwave rotational spectrum and internal rotation in gauche ethyl alcohol  

Microsoft Academic Search

The microwave torsional-rotational spectra of several species of gauche ethyl alcohol have been assigned and analyzed. The species studied are CH3CH2OH, CH3CH2OD, CH2DCH2OH, and CH2DCH2OD, both methyl symmetric and asymmetric forms of the last two species. Rotational coefficients have been determined for all species. For the normal species, the components of the dipole moment have been determined as ||mua||=1.264+\\/-0.010 D,

Ramesh K. Kakar; C. Richard Quade

1980-01-01

418

Detection of N-acetyltranylcypromine and glucuronide of phenyl-hydroxylated N-acetyltranylcypromine from tranylcypromine-dosed rat urine: Pharmacological implications  

Microsoft Academic Search

In order to use for metabolic studies of tranylcypromine (TCP), TCP-phenyl-d5 was synthesized via the intermediates, 3-benzoylpropionic acid-d5 andtrans-2-phenylcyclopropanecarboxylic acid-d5. TCP (0.22 mmole\\/kg) and its deuterated analog were administered s.c. to the rats and GC\\/MS analyses of the urines led to\\u000a the detection of N-acetyltranylcypromine (ATCP) and glucuronide conjugate of phenyl-hydroxylated ATCP. MAO activities in rat\\u000a brain were measured using

Gun II Kang; Hee Kyung Choi

1986-01-01

419

Effect of common exon variant (p.P364L) on drug glucuronidation by the human UDP-glucuronosyltransferase 1 family.  

PubMed

The UDP-glucuronosyltransferases (UGTs) comprise a major excretion pathway for diverse endogenous and exogenous substrates. Relations are reported between polymorphisms of exon 1 of UGT1 and drug side effects or carcinogenesis, but few studies exist of common exon polymorphisms that exert influence throughout UGT1 isoforms. We analysed the polymorphism c.1091C>T, resulting in the amino acid substitution of p.P364L, found on common exon 4. We studied 187 healthy, adult Japanese volunteers. The allele frequency was 0.0053. We investigated the effect of p.P364L on glucuronidation of ?-estradiol, acetaminophen, propofol, lamotrigine, imipramine and cyproheptadine in an in vitro expression study. The V(max) values for ?-estradiol of p.P364L-UGT1A1, 1A3, 1A7, 1A8 and 1A10 were 36.6%, 82.1%, 26.8%, 29.2% and 22.5%, respectively, of the corresponding wild-type. Glucuronidation activity towards acetaminophen of p.P364L-UGT1A1, 1A6, 1A7, 1A8, 1A9 and 1A10 was 50.3%, 46.4%, 17.2%, 44.1%, 5.0% and 42.8%, respectively, of wild-type. Glucuronidation activity towards propofol of p.P364L-UGT1A7, 1A8, 1A9 and 1A10 was 44.0%, 49.8%, 29.0% and 71.1%, respectively, of wild-type. Substrate inhibition was observed in lamotrigine, cyproheptadine and imipramine glucuronidation by wild-type UGT1A4 but vanished for p.P364L. The presence of p.P364L near the UDP-glucuronic acid binding site could lead to extensive reduction of enzyme activity of many UGT1s. Our results suggest that p.P364L is an important mutation that could give rise to adverse effects of various drugs, or carcinogenesis. It is important to study common exon mutations because these can reduce activity of all UGT1 isoforms. PMID:21726413

Mimura, Yu; Maruo, Yoshihiro; Ohta, Yoriko; Sato, Hiroshi; Takeuchi, Yoshihiro

2011-08-18

420

Determination of resveratrol and its sulfate and glucuronide metabolites in plasma by LC-MS/MS and their pharmacokinetics in dogs  

PubMed Central

An analytical approach for the determination of trans-resveratrol (3,5,4?-trihydroxy-trans-stilbene) and its glucuronide and sulfate conjugates in dog plasma by LC-MS/MS (without enzymatic hydrolysis of the conjugates) was validated to support pre-clinical toxicological and pharmacological studies. The approach required two independent sample extractions and consequent instrument runs. Samples for resveratrol determination were prepared by protein precipitation with acetonitrile; acetonitrile-methanol was used instead for resveratrol metabolites. Chromatographic separation was performed using a C18 column (30 × 2.0 mm) at a flow rate of 0.25 mL/min. For resveratrol the mobile phase consisted of A: 5 mM ammonium acetate in water-isopropanol (98:2, v/v) and B: methanol-isopropanol (98:2, v/v) and for metabolites the mobile phase was modified as follows: A: 0.1% (v/v) formic acid in water and B: 0.1% (v/v) formic acid in acetonitrile. Total run time was 12 min for each run with retention times of about 4-5 min for all analytes. A turbo ion spray source was used operating in negative mode for resveratrol and resveratrol sulfate and in positive mode for resveratrol glucuronide. Calibration curves were linear from 5 to 1000 ng/mL for resveratrol and its glucuronide, and 10 to 2000 ng/mL for resveratrol sulfate. Linearity was assessed using the internal standard method for resveratrol and the external standard method for the metabolites. Method accuracy was 90 to 112% of the true value for all analytes with precision of 9 %RSD or less for all validation experiments. The validated method was applied to a preclinical toxicology study in dogs after oral administration (200 to 1200 mg/kg) of the agent. Peak plasma resveratrol concentration (Cmax) for most animals was observed within 1 to 5 h of dosing, with group mean values in the 1.7 to 9.9 ?g/mL (7.5 to 43 ?M) range. Area under the plasma concentration-time curve (AUC) mean values for resveratrol ranged from 3.6 to 44 h*?g/mL for all study groups and were generally proportional to the dose, with no consistent statistically significant changes observed for gender or number of doses. Mean molecular-weight adjusted ratios of resveratrol metabolites to resveratrol for AUC ranged from 1 to 9 for resveratrol glucuronide and from 2 to 11 for resveratrol sulfate.

Muzzio, Miguel; Huang, Zhihua; Hu, Shu-Chieh; Johnson, William D.; McCormick, David L.; Kapetanovic, Izet M.

2011-01-01

421

Fragrance material review on ethyl phenyl carbinyl acetate.  

PubMed

A toxicologic and dermatologic review of ethyl phenyl carbinyl acetate when used as a fragrance ingredient is presented. Ethyl phenyl carbinyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for ethyl phenyl carbinyl acetate were evaluated, then summarized, and includes: physical properties; acute toxicity; skin irritation; and skin sensitization data. A safety assessment of the entire AAASAE will be published simultaneously with this document; please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22433983

McGinty, D; Letizia, C S; Api, A M

2012-03-13

422

Getting the lead out with ethyl t-butyl ether  

SciTech Connect

If automobile fuels of the future aren't made up largely of alcohols and their derivatives, then those materials will at least make up a significant part of gasoline-based fuels. This can be predicted because the public demands octane levels that are otherwise difficult to achieve now that lead compounds are being eliminated from fuels. A study of the future use of ethyl alcohol in gasoline was presented recently to the U.S. Congress. Prepared by Meridian Ccorp. of Alexandria, VA., and based on expert counsel provided under the Farm Disaster Assistance Act, the report gives a major role to ethanol - at least a doubling of production to 1.7 billion gallons per year in the next five years. Although ethanol is miscible in all proportions with gasoline, most blends - the so-called ''gasohols'' - contain only about 10% alcohol. An alternative to using pure ethanol that could offer several advantages is treating the alcohol with iso-butylene and using the resulting t-butyl ether. Table 1 in this article enables one to compare the significant properties of methyl and ethyl alcohols and methyl and ethyl t-butyl ethers (MTBE and ETBE, respectively). After discussing these properties, the authors examine candidate ways to make ETBE. They use the term ''candidate'' because, to their knowledge, no one is yet making ETBE on a commercial scale.

Iborra, M.; Izquierdo, J.F.; Tejero, J.; Cunill, F.

1988-02-01

423

Effect of microsomal enzyme inducers on biliary and urinary excretion of acetaminophen metabolites in rats. Decreased hepatobiliary and increased hepatovascular transport of acetaminophen-glucuronide after microsomal enzyme induction.  

PubMed

Treatment of rats with phenobarbital (PB), 3-methylcholanthrene, and pregnenolone-16 alpha-carbonitrile increased the total (biliary plus urinary) excretion of thioether and glucuronic acid conjugates of acetaminophen (AA) without influencing AA-sulfate excretion, suggesting that these microsomal enzyme inducers enhance both cytochrome P-450-mediated toxication and UDP-glucuronosyltransferase-mediated detoxication of AA. However, induction with transstilbene oxide (TSO) did not increase the total excretion of AA-thioethers or AA-glucuronide and decreased AA-sulfate excretion. In addition, all inducers increased the ratio of AA metabolites excreted into urine over that excreted into bile. The extent of this shift from biliary to urinary excretion was dependent on both the AA metabolite and the inducer. The largest shift in the excretory route was seen with AA-glucuronide and induction with PB and TSO as inducers. Specifically, PB and TSO treatments decreased biliary excretion of AA-glucuronide by 70 and 89%, respectively, and increased its blood concentration up to 6- and 11-fold and urinary excretion 3- and 3.6-fold, respectively. Galactosamine depletes UDP-glucuronic acid from the liver only, thereby inhibiting hepatic but not extrahepatic glucuronidation. Galactosamine treatment prevented the PB-induced increase in AA-glucuronide in blood and urine. This suggests that the PB-induced increases in AA-glucuronide in blood and urine originated from the liver. Thus, microsomal enzyme inducers not only influence xenobiotic biotransformation, but may also after the contribution of the excretory routes (i.e. bile and urine) in the elimination of xenobiotic metabolites by changing the direction of hepatic transport. PMID:1970767

Gregus, Z; Madhu, C; Klaassen, C D

424

Effect of ether anaesthesia on pharmacokinetics of N-(2 hydroxy ethyl) 2-phenyl ethyl carbamate; Inhibition of its enterohepatic circulation  

PubMed Central

1 The effect of the ether anaesthesia on the plasma half-life of N-(2 hydroxy ethyl) 2-phenyl ethyl carbamate has been studied in rats. 2 The plasma half-life of the carbamate was considerably shorter in animals anaesthetized with ether prior to drug administration than in control rats. 3 The longer plasma half-life of the carbamate in control animals was shown to be due to enterohepatic circulation. 4 Inhibition of this phenomenon by ether was responsible for the shorter plasma half-life of the carbamate in animals anaesthetized with this agent before drug administration. 5 The possible mechanisms by which the ether-induced effect is brought about are discussed.

Obianwu, Hope O.

1974-01-01

425

Fatty Acid Ethyl Esters in Meconium: Are They Biomarkers of Fetal Alcohol Exposure and Effect?  

PubMed Central

Background Biomarkers of fetal exposure to alcohol are important to establish so that early detection and intervention can be made on these infants to prevent undesirable outcomes. The aim of this study was to analyze long-chain fatty acid ethyl esters (FAEEs) in meconium as potential biomarkers of fetal alcohol exposure and effect. Methods Fatty acid