Note: This page contains sample records for the topic ethyl glucuronide etg from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: August 15, 2014.
1

SENSITIVITY OF COMMERCIAL ETHYL GLUCURONIDE (ETG) TESTING IN SCREENING FOR ALCOHOL ABSTINENCE  

Microsoft Academic Search

The '80 h Ethyl Glucuronide (EtG) test' has become an idiom of the alcohol testing community, a review of the literature shows this window of detection applies only to extreme cases. EtG testing is becoming more common as a method to test for alcohol consumption in individuals who have been ordered to abstain from alcohol consumption. We tested 19 subjects

MARK H. WOJCIK; JEFFREY S. HAWTHORNE

2007-01-01

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

Quantification of fatty acid ethyl esters (FAEE) and ethyl glucuronide (EtG) in meconium from newborns for detection of alcohol abuse in a maternal health evaluation study  

Microsoft Academic Search

Fatty acid ethyl esters (FAEE) and ethyl glucuronide (EtG) were determined in 602 meconium samples in a maternal health evaluation\\u000a study for detection of gestational alcohol consumption. A validated headspace solid phase microextraction method in combination\\u000a with GC-MS was used for FAEE and the cumulative concentration of ethyl palmitate, ethyl linoleate, ethyl oleate, and ethyl\\u000a stearate with a cut-off of

Abdulsallam Bakdash; Pascal Burger; Tamme W. Goecke; Peter A. Fasching; Udo Reulbach; Stefan Bleich; Martin Hastedt; Michael Rothe; Matthias W. Beckmann; Fritz Pragst; Johannes Kornhuber

2010-01-01

4

Quantification of fatty acid ethyl esters (FAEE) and ethyl glucuronide (EtG) in meconium from newborns for detection of alcohol abuse in a maternal health evaluation study.  

PubMed

Fatty acid ethyl esters (FAEE) and ethyl glucuronide (EtG) were determined in 602 meconium samples in a maternal health evaluation study for detection of gestational alcohol consumption. A validated headspace solid phase microextraction method in combination with GC-MS was used for FAEE and the cumulative concentration of ethyl palmitate, ethyl linoleate, ethyl oleate, and ethyl stearate with a cut-off of 500 ng/g was applied for interpretation. A new and simple method was developed and validated for quantification of EtG from 10-20 mg meconium with D(5)-EtG as internal standard consisting of 30 min. extraction with methanol/water (1:1, v/v), evaporation of methanol, filtration of the aqueous solution through a cellulose filter and injection into LC-MS-MS. The limits of detection and quantification for EtG were 10 and 30 ng/g, the recovery 86.6 to 106.4% and the standard deviation of the concentrations ranged from 13% at 37 ng/g to 5% at 46,700 ng/g (N = 6). FAEE above the cut-off were found in 43 cases (7.1%) with cumulative concentrations between 507 and 22,580 ng/g and with one outlier of about 150,000 ng/g (EtG not detected). EtG was detected in 97 cases (16.3%) and concentrations between LOD and 10,200 ng/g with another outlier of 82,000 ng/g (FAEE 10,500 ng/g). Optimal agreement between the two markers was obtained with a cut-off for EtG of 274 ng/g and 547 cases with both FAEE- and EtG-negative, 33 cases with both FAEE- and EtG-positive, nine cases with FAEE-positive and EtG-negative, and seven cases with FAEE-negative and EtG-positive. Differences in physical, chemical, and biochemical properties and in the pharmacokinetic behavior are discussed as reasons for the deviating cases. In none of the 602 cases, serious alcohol consumption was reported by the mothers and no evidence for gestational ethanol exposure was observed in the medical investigation of the newborns. It is concluded that the combined use of FAEE and EtG in meconium as markers for fetal alcohol exposure essentially increases the accuracy of the interpretation and helps to avoid false positive and false-negative results. PMID:20145912

Bakdash, Abdulsallam; Burger, Pascal; Goecke, Tamme W; Fasching, Peter A; Reulbach, Udo; Bleich, Stefan; Hastedt, Martin; Rothe, Michael; Beckmann, Matthias W; Pragst, Fritz; Kornhuber, Johannes

2010-04-01

5

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

2013-12-01

6

Development of a new immunoassay for the detection of ethyl glucuronide (EtG) in meconium: validation with authentic specimens analyzed using LC-MS/MS. Preliminary results.  

PubMed

Abstract Background: Ethyl glucuronide (EtG) measurement in neonatal meconium has emerged as a reliable marker to objectively assess prenatal exposure to maternal ethanol complementary to fatty acid ethyl ester (FAEEs) measurement. The detection of EtG in meconium is currently a lengthy, difficult and expensive process using liquid chromatography tandem mass spectrometry (LC-MS/MS) as the analytical procedure. An enzyme-linked immunosorbent assay (ELISA) for the identification of EtG in meconium was developed, validated and applied to authentic meconium specimens from newborns collected in Europe. Methods: The ELISA procedure was calibrated using 0.45, 0.9, 1.35 and 1.8 nmol/g (100, 200 300 and 400 ng/g) standards. Meconium (0.25 g) was mixed thoroughly, with extraction buffer (pH 7.3; 0.5 mL). The tube was capped, sonicated, centrifuged and the supernatant was decanted. An aliquot of the extract (50 ?L) was placed in the well of the microplate followed by enzyme conjugate (150 ?L). The plate was incubated for 1 h, washed with deionized water, dried and substrate (200 ?L) was added. After 30 min incubation, stop solution was added and the plate was read at 450 nm and 650 nm. Samples were also analyzed for EtG and FAEEs by validated LC-MS/MS assays. Results: Using an EtG cut-off of 0.9 nmol/g for both ELISA screening test and confirmatory LC-MS/MS, immunoassay sensitivity was 100%; specificity 78%; positive-predictive value (PPV) 29% and negative-predictive value (NPV) 100%. Conclusions: The assay is proposed as a preliminary screening test for the meconium of newborns suspected of being born to mothers drinking alcohol during pregnancy. PMID:24607921

Pichini, Simona; Morini, Luca; Pacifici, Roberta; Tuyay, James; Rodrigues, Warren; Solimini, Renata; Garcia-Algar, Oscar; Ramis, Juan; Moore, Christine

2014-08-01

7

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

2013-06-01

8

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

9

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

10

Segmental determination of ethyl glucuronide in hair: A pilot study  

Microsoft Academic Search

Ethyl glucuronide (EtG) is a minor metabolite of ethanol. Its detection in hair is more and more studied in both clinical and forensic context for the purpose of alcohol abuse monitoring. In this pilot study, hair specimens from 15 patients included in a treatment program after alcohol abuse cessation, were segmented and analyzed for EtG. The results were then compared

Brice M. R. Appenzeller; Resmi Agirman; Paul Neuberg; Michel Yegles; Robert Wennig

2007-01-01

11

Ethyl glucuronide: Unusual distribution between head hair and pubic hair  

Microsoft Academic Search

Ethyl glucuronide (EtG) is a minor metabolite of ethanol that can be detected in hair. In some specific situations, head hair can be missing, and therefore, alternative anatomical locations of hair are of interest. In this study, paired hair specimens (head hair and pubic hair) from eight social drinkers were analyzed for EtG. Each sample was decontaminated by two dichloromethane

Pascal Kintz; Marion Villain; Emilie Vallet; Mathieu Etter; Guillaume Salquebre; Vincent Cirimele

2008-01-01

12

Influence of preservatives on the stability of ethyl glucuronide and ethyl sulphate in urine  

Microsoft Academic Search

BackgroundEthyl glucuronide (EtG) and ethyl sulphate (EtS) are specific and sensitive markers of ethanol consumption well established in monitoring withdrawal treatment in patients with chronic alcoholism. Recently, bacterial decomposition as well as in vitro and post-mortem formation of EtG was reported. The aim of this study was to investigate the influence of different preservatives on the stability of EtG and

Annette Thierauf; Annerose Serr; Claudia C. Halter; Ali Al-Ahmad; Sumandeep Rana; Wolfgang Weinmann

2008-01-01

13

Detection Times for Urinary Ethyl Glucuronide and Ethyl Sulfate in Heavy Drinkers during Alcohol Detoxification  

Microsoft Academic Search

Aims: Ethyl glucuronide (EtG) and ethyl sulfate (EtS) are conjugated ethanol metabolites formed in low amounts after alcohol consumption. Compared with ethanol, EtG and EtS are excreted in urine for a prolonged time, making them useful as sensitive alcohol biomarkers. This study determined the detection times for EtG and EtS in alcoholic patients undergoing alcohol detoxification. Methods: Alcohol-dependent patients (n

Anders Helander; Christoph Fehr; Norbert Dahmen; Olof Beck

2008-01-01

14

Ethyl glucuronide concentration in hair is not influenced by pigmentation.  

PubMed

This work shows that the concentration of ethyl glucuronide (EtG) in hair, a marker for the evaluation of the alcohol consumption, is not influenced by the presence or absence of melanin. The results confirm that, unlike many other substances, the EtG determination in hair has not to take into account the hair colour for the correct interpretation of hair testing results. PMID:17517821

Appenzeller, Brice M R; Schuman, Marc; Yegles, Michel; Wennig, Robert

2007-01-01

15

EVALUATION OF A NEW IMMUNOASSAY FOR URINARY ETHYL GLUCURONIDE TESTING  

Microsoft Academic Search

Aims: The minor ethanol metabolite ethyl glucuronide (EtG) is used as a sensitive and specific test for recent alcohol consumption with clinical and forensic applications. This study evaluated a new enzyme immunoassay (DRI-EtG EIA, Microgenics Corp.) for determination of the EtG concentration in urine samples. Methods: Evaluation was done using the kit calibrators (range 0-5.0 mg\\/L) and controls, an external

OLOF BECK; ANDERS HELANDER

2007-01-01

16

Comparison of ethyl glucuronide and fatty acid ethyl ester concentrations in hair of alcoholics, social drinkers and teetotallers  

Microsoft Academic Search

In previous investigations hair analysis for ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEE) proved to be suitable for the detection of excessive alcohol consumption. The aim of this study was to compare EtG and FAEE concentrations in hair of alcoholics, social drinkers and teetotallers. Hair samples from 10 alcoholics in withdrawal treatment, 11 fatalities with documented excessive alcohol

M. Yegles; A. Labarthe; V. Auwärter; S. Hartwig; H. Vater; R. Wennig; F. Pragst

2004-01-01

17

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

18

Ethyl glucuronide and ethyl sulphate determination in serum by liquid chromatography–electrospray tandem mass spectrometry  

Microsoft Academic Search

BackgroundEthyl glucuronide (EtG) and ethyl sulphate (EtS) are two ethanol metabolites that can be detected in serum up to 8 h after ethanol elimination. Their presence is therefore indicative of recent ethanol consumption in case of delayed sampling after an event (e.g. car crash).

Luca Morini; Lucia Politi; Alessandra Zucchella; Aldo Polettini

2007-01-01

19

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

20

A pharmacokinetic study of ethyl glucuronide in blood and urine: Applications to forensic toxicology  

Microsoft Academic Search

This pharmacokinetic study investigated the kinetics of ethanol and its metabolite ethyl glucuronide (EtG) in blood and urine during the whole time course of absorption and elimination. There are few previous studies on the kinetics of EtG in blood, and we wanted to evaluate whether such knowledge could yield valuable information regarding the time of ethanol ingestion in forensic cases,

Gudrun Høiseth; Jean Paul Bernard; Ritva Karinen; Lene Johnsen; Anders Helander; Asbjørg S. Christophersen; Jørg Mørland

2007-01-01

21

Influence of ethanol dose and pigmentation on the incorporation of ethyl glucuronide into rat hair  

Microsoft Academic Search

Ethyl glucuronide (EtG) is a minor and specific metabolite of ethanol. It is incorporated into growing hair, allowing a retrospective detection of alcohol consumption. However, the suitability of quantitative EtG measurements in hair to determine the quantity of alcohol consumed has not clearly been demonstrated yet. The purpose of this study was to evaluate the influence of ethanol dose and

Hicham Kharbouche; Nadia Steiner; Marie Morelato; Christian Staub; Benjamin Boutrel; Patrice Mangin; Frank Sporkert; Marc Augsburger

2010-01-01

22

Practical use of ethyl glucuronide and ethyl sulfate in postmortem cases as markers of antemortem alcohol ingestion  

Microsoft Academic Search

In postmortem toxicology, it could be difficult to determine whether a positive blood ethanol concentration reflects antemortem\\u000a ingestion or postmortem synthesis of alcohol. Measurement of the nonoxidative ethanol metabolite ethyl glucuronide (EtG) has\\u000a been suggested as a marker of antemortem ingestion of alcohol, but EtG might degrade postmortem which could make interpretation\\u000a difficult. So far, the published articles concern EtG

Gudrun Høiseth; Ritva Karinen; Asbjørg Christophersen; Jørg Mørland

2010-01-01

23

False-positive ethyl glucuronide immunoassay screening associated with chloral hydrate medication as confirmed by LC–MS\\/MS and self-medication  

Microsoft Academic Search

BackgroundUrine-ethyl glucuronide (EtG) concentrations are considered as a specific marker of recent alcohol consumption. We describe false-positive EtG screening results by the DRI® ethyl glucuronide enzyme immunoassay caused by chloral hydrate intake.

Torsten Arndt; Birgit Gierten; Brunhilde Güssregen; Annika Werle; Joachim Grüner

2009-01-01

24

Markers of chronic alcohol use in hair: Comparison of ethyl glucuronide and cocaethylene in cocaine users  

Microsoft Academic Search

Two direct ethanol metabolites, namely ethyl glucuronide (EtG) and cocaethylene (CE), in the hair of cocaine (COC) users were compared in this study.Hair samples (n=68) were submitted to the determination of EtG (by liquid chromatography-electrospray-tandem mass spectrometry) and of COC and metabolites, including CE (by gas chromatography-mass spectrometry). Quantitative and qualitative results were compared.No quantitative correlation was found between EtG

Lucia Politi; Alessandra Zucchella; Luca Morini; Cristiana Stramesi; Aldo Polettini

2007-01-01

25

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

26

Kinetics in serum and urinary excretion of ethyl sulfate and ethyl glucuronide after medium dose ethanol intake  

Microsoft Academic Search

The direct ethanol metabolites, ethyl glucuronide (EtG) and ethyl sulfate (EtS), are of increasing importance for clinical\\u000a and forensic applications, but there are only few studies on the kinetics of EtG in serum and none on EtS. In this study,\\u000a 13 volunteers (social drinkers) drank ethanol in the form of white wine to reach a blood alcohol concentration of 0.51?±?0.17 g\\/kg,

Claudia C. Halter; Sebastian Dresen; Volker Auwaerter; Friedrich M. Wurst; Wolfgang Weinmann

2008-01-01

27

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

28

Segmental determination of ethyl glucuronide in hair: a pilot study.  

PubMed

Ethyl glucuronide (EtG) is a minor metabolite of ethanol. Its detection in hair is more and more studied in both clinical and forensic context for the purpose of alcohol abuse monitoring. In this pilot study, hair specimens from 15 patients included in a treatment program after alcohol abuse cessation, were segmented and analyzed for EtG. The results were then compared to their self-reported past alcohol consumption and to their blood biomarkers values (GGT, MCV, ASAT, ALAT). EtG concentrations measured in hair varied from 8 to 261 pg/mg. The pattern of EtG concentration detected in the different hair segments matched with the drinking history of patients, displaying variations (increase and decrease) in alcohol consumption and also time of cessation. Results also demonstrated the existence of a significant correlation (r(p)=0.5357; p=0.0390) between EtG concentration in hair and the amount of alcohol intake. Variations in the EtG concentrations with respect to hair segments may provide an overview of the drinking history of patients. Moreover, EtG concentration in hair may help to estimate the daily alcohol intake. PMID:17337139

Appenzeller, Brice M R; Agirman, Resmi; Neuberg, Paul; Yegles, Michel; Wennig, Robert

2007-12-20

29

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

30

Measurement of ethyl glucuronide in vitreous humor with liquid chromatography–mass spectrometry  

Microsoft Academic Search

BackgroundIt is important to detect alcohol intake in postmortem investigations. However it can be difficult to interpret the results of alcohol analysis in putrefied corpses. To avoid this difficulty, there have been studies on detection of ethyl glucuronide (EtG), a non-oxidative metabolite of ethyl alcohol. The aim of this study was investigate EtG levels in vitreous humor (VH), a valuable

Alper Keten; Ali Riza Tumer; Aysun Balseven-Odabasi

2009-01-01

31

Proton nuclear magnetic resonance spectroscopic determination of ethanol-induced formation of ethyl glucuronide in liver  

Microsoft Academic Search

Ethyl glucuronide (ethyl-?-d-6-glucosiduronic acid, EtG), a unique metabolite of ethanol, has received much recent attention as a sensitive and specific biological marker of ethanol consumption. Formed in the liver via conjugation of ethanol with activated glucuronate, EtG remains detectable in serum, plasma, and hair for days after ethanol abuse. Thus far, gas chromatography–mass spectrometry and enzyme-linked immunosorbent assays have been

Peter C. Nicholas; Daniel Kim; Fulton T. Crews; Jeffrey M. Macdonald

2006-01-01

32

Examination of sex differences in fatty acid ethyl ester and ethyl glucuronide hair analysis.  

PubMed

Clinical studies examining performance of fatty acid ethyl esters (FAEE) and ethyl glucuronide (EtG) in identifying excessive alcohol consumption have been primarily conducted in male populations. An impact of hair cosmetics in producing both false-negative EtG results and false-positive FAEE results has been demonstrated, suggesting a possible bias in female populations. This study evaluates FAEE-positive hair samples (>0.50?ng/mg) from n?=?199 female and n?=?73 male subjects for EtG. Higher FAEE/EtG concordance was observed amongst male over female subjects. Performance of multiple proposed EtG cut-off levels were assessed; amongst female samples, FAEE/EtG concordance was 36.2% (30?pg/mg), 36.7% (27?pg/mg), and 43.7% (20?pg/mg). Non-coloured hair demonstrated a two-fold increase in concordance (41.8 v. 20.8%) over coloured hair in the female cohort. FAEE levels did not differ between male and female subjects; however they were lower in coloured samples (p?=?0.046). EtG was lower in female subjects (p?=?0.019) and coloured samples (p?=?0.026). A total of n?=?111 female samples were discordant. Amongst discordant samples (EtG-negative), 26% had evidence of recent alcohol use including consultation histories (n?=?20) and detectable cocaethylene (n?=?9); 29% of discordant samples were coloured. False-negative risk with ethyl glucuronide analysis in females was mediated by cosmetic colouring. These findings suggest that combined analysis of FAEE and EtG is optimal when assessing a female population and an EtG cut-off of 20?pg/mg is warranted when using combined analysis. While concordant FAEE/EtG-positive findings constitute clear evidence, discordant FAEE/EtG findings should still be considered suggestive evidence of chronic excessive alcohol consumption. PMID:24817046

Gareri, Joey; Rao, Chitra; Koren, Gideon

2014-06-01

33

Ethyl glucuronide and ethyl sulfate in meconium and hair-potential biomarkers of intrauterine exposure to ethanol  

Microsoft Academic Search

This study investigated ethyl glucuronide (EtG) and ethyl sulfate (EtS) concentration in meconium and in maternal and neonatal hair (HEtG and HFAEEs, respectively) as potential markers of intrauterine exposure to ethanol together with meconium fatty acid ethyl esters (FAEEs) in a cohort of 99 mother–infant dyads, 49 coming from the Arcispedale of Reggio Emilia (Italy) and 50 from the Hospital

L. Morini; E. Marchei; F. Vagnarelli; O. Garcia Algar; A. Groppi; L. Mastrobattista; S. Pichini

2010-01-01

34

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

35

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

36

Improvement of ethyl glucuronide determination in human urine and serum samples by solid-phase extraction  

Microsoft Academic Search

An improved method for the determination of ethyl glucuronide (EtG) in human serum and urine was developed using solid-phase extraction (SPE) and gas chromatography (GC) with mass spectrometric detection (MS). EtG was isolated from serum and urine using aminopropyl SPE columns after deproteination with perchloric acid and hydrochloric acid, respectively. The chromatographic separation was performed on a DB 1701 fused-silica

Ines Janda; Andreas Alt

2001-01-01

37

A study of distribution of ethyl glucuronide in different keratin matrices  

Microsoft Academic Search

Ethyl glucuronide (EtG) is a direct metabolite of ethanol, frequently used as a biomarker of alcohol abuse. To this purpose, EtG is preferentially determined in hair samples, using a cut-off value of 30pg\\/mg to discriminate between social and heavy drinkers, as recently fixed by an international consensus conference. Although this cut-off value is assumed for head hair, alternative matrices, such

V. Pirro; D. Di Corcia; S. Pellegrino; M. Vincenti; B. Sciutteri; A. Salomone

2011-01-01

38

Determination of ethyl glucuronide in urine using reversed-phase HPLC and pulsed electrochemical detection (Part II)  

Microsoft Academic Search

A direct, versatile method for the determination of ethyl glucuronide (EtG), a biomarker of ethanol consumption, in urine has been developed using reversed-phase liquid chromatography with pulsed electrochemical detection (PED). EtG and methyl glucuronide (MetG), which serves as an internal standard, are readily separated using a mobile phase consisting of 1% acetic acid\\/acetonitrile (98\\/2, v\\/v). Post-column addition of NaOH allows

Romina Kaushik; William R. LaCourse; Barry Levine

2006-01-01

39

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

40

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

41

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

42

Combined use of fatty acid ethyl esters and ethyl glucuronide in hair for diagnosis of alcohol abuse: Interpretation and advantages  

Microsoft Academic Search

In this study the combined use of fatty acid ethyl esters (FAEE) and ethyl glucuronide (EtG) for diagnoses of chronically excessive alcohol abuse is investigated at 174 hair samples from driving ability examination, workplace testing and child custody cases for family courts and evaluated with respect to the basics of interpretation. Using the cut-off values of 0.50ng\\/mg for FAEE and

F. Pragst; M. Rothe; B. Moench; M. Hastedt; S. Herre; D. Simmert

2010-01-01

43

Ethyl-glucuronide and ethyl-sulfate in placental and fetal tissues by liquid chromatography coupled with tandem mass spectrometry  

Microsoft Academic Search

The aim of this study was to develop a method for the determination of ethyl-glucuronide (EtG) and ethyl-sulfate (EtS), two direct ethanol metabolites, in early placental and fetal human tissues, as potential biomarkers of transplacental ethanol transfer from the mother to the fetus. Placental and fetal tissue samples were obtained from women undergoing voluntary termination of pregnancy at 12weeks of

Luca Morini; Maria Falcón; Simona Pichini; Oscar Garcia-Algar; Paolo Danesino; Angelo Groppi; Aurelio Luna

2011-01-01

44

Ethyl sulphate and ethyl glucuronide in vitreous humor as postmortem evidence marker for ethanol consumption prior to death  

Microsoft Academic Search

To clarify the circumstances of death, the degree of inebriation is of importance in many cases, but for several reasons the determination of the ethanol concentration in post-mortem samples can be challenging and the synopsis of ethanol and the direct consumption markers ethyl glucuronide (EtG) and ethyl sulphate (EtS) has proved to be useful. The use of a rather stable

Annette Thierauf; Jürgen Kempf; Markus Große Perdekamp; Volker Auwärter; Heike Gnann; Ariane Wohlfarth; Wolfgang Weinmann

2011-01-01

45

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

Microsoft Academic Search

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

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

46

Proton nuclear magnetic resonance spectroscopic determination of ethanol-induced formation of ethyl glucuronide in liver.  

PubMed

Ethyl glucuronide (ethyl-beta-D-6-glucosiduronic acid, EtG), a unique metabolite of ethanol, has received much recent attention as a sensitive and specific biological marker of ethanol consumption. Formed in the liver via conjugation of ethanol with activated glucuronate, EtG remains detectable in serum, plasma, and hair for days after ethanol abuse. Thus far, gas chromatography-mass spectrometry and enzyme-linked immunosorbent assays have been developed to detect trace quantities of EtG for forensic purposes, but reports of the nuclear magnetic resonance (NMR) properties of EtG have been scarce. Herein we present the first report of EtG determination using proton NMR spectroscopy. We collected 700-MHz proton spectra of liver extracts from rats treated with a 4-day binge ethanol protocol (average ethanol dose: 8.6g/kg/day). An unexpected signal (triplet, 1.24 ppm) appeared in ethanol-treated liver extracts but not in control samples; based on chemical shift and multiplicity, we suspected EtG. We observed quantitative hydrolysis of the unknown species to ethanol while incubating our samples with beta-glucuronidase, confirming that the methyl protons of EtG were responsible for the triplet at 1.24 ppm. This study demonstrates that proton NMR spectroscopy is capable of detecting EtG and that future NMR-based metabolomic studies may encounter this metabolite of ethanol. PMID:17027904

Nicholas, Peter C; Kim, Daniel; Crews, Fulton T; Macdonald, Jeffrey M

2006-11-15

47

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

48

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

49

Ethyl glucuronide and ethyl sulfate in meconium and hair-potential biomarkers of intrauterine exposure to ethanol.  

PubMed

This study investigated ethyl glucuronide (EtG) and ethyl sulfate (EtS) concentration in meconium and in maternal and neonatal hair (HEtG and HFAEEs, respectively) as potential markers of intrauterine exposure to ethanol together with meconium fatty acid ethyl esters (FAEEs) in a cohort of 99 mother-infant dyads, 49 coming from the Arcispedale of Reggio Emilia (Italy) and 50 from the Hospital del Mar of Barcelona (Spain). FAEEs, EtG and EtS were measured in meconium samples using liquid chromatography-tandem mass spectrometry. A head space-solid phase microextraction-gas chromatography-mass spectrometry was used to test HEtG and HFAEEs in hair samples from mothers and their newborns. Eighty-two meconium samples (82.8%) tested positive for EtG, 19 (19.2%) for EtS while 22 (22.2%) showed FAEEs levels higher than 2 nmol/g, the cut-off used to differentiate daily maternal ethanol consumption during pregnancy from occasional or no use. Although EtG and EtS in meconium did not correlate with total FAEEs concentration, a good correlation between EtG, EtS and ethyl stearate was observed. Moreover, EtG correlated well with ethyl palmitoleate, while EtS with ethyl laurate, myristate and linolenate. Neither maternal nor neonatal hair appears as good predictors of gestational ethanol consumption and subsequent fetal exposure in these mother-infant dyads. In conclusion, these data show that meconium is so far the best matrix in evaluating intrauterine exposure to ethanol, with EtG and EtS being potentially good alternative biomarkers to FAEEs. PMID:20060246

Morini, L; Marchei, E; Vagnarelli, F; Garcia Algar, O; Groppi, A; Mastrobattista, L; Pichini, S

2010-03-20

50

Comparison of ethyl glucuronide and fatty acid ethyl ester concentrations in hair of alcoholics, social drinkers and teetotallers.  

PubMed

In previous investigations hair analysis for ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEE) proved to be suitable for the detection of excessive alcohol consumption. The aim of this study was to compare EtG and FAEE concentrations in hair of alcoholics, social drinkers and teetotallers. Hair samples from 10 alcoholics in withdrawal treatment, 11 fatalities with documented excessive alcohol consumption, four moderate social drinkers who consumed up to 20 g ethanol per day, and three strict teetotallers were analysed. After external degreasing with n-heptane, extraction with a dimethyl sulfoxide/n-heptane mixture and headspace solid-phase microextraction of the extracts, four fatty acid ethyl esters (FAEEs) (ethyl myristate, ethyl palmitate, ethyl oleate and ethyl stearate) were analysed by gas chromatography-mass spectrometry (GC-MS) with deuterated internal standards. EtG was determined by GC-MS/NCI after ultrasonication of the samples with H2O, cleanup by SPE with aminopropyl columns and PFP derivatisation. The following concentrations were measured for the four groups: teetotallers EtG < 0.002 ng/mg, FAEE 0.05-0.37 ng/mg, moderate social drinkers EtG < 0.002 ng/mg, FAEE 0.26-0.50 ng/mg, alcoholic patients EtG 0.030-0.415 ng/mg, FAEE 0.65-20.50 ng/mg and the fatalities with alcohol history EtG 0.072-3.380 ng/mg, FAEE 1.30-30.60 ng/mg. The results confirm that by using a cut-off value of the sum of FAEE > 1 ng/mg and/or a positive EtG result in hair, excessive alcohol consumption can be identified using hair analysis. However, no significant correlation between the EtG and FAEE concentrations in the positive cases could be shown. Segmental analysis of some of the specimens did not reveal the same distribution for EtG compared to FAEE in hair, and no chronological accordance compared to the self-reported alcohol consumption could be observed for both parameters. These different results of both methods are discussed in terms of differences between EtG and FAEE in mechanism of formation and incorporation into hair and elimination from hair. PMID:15451089

Yegles, M; Labarthe, A; Auwärter, V; Hartwig, S; Vater, H; Wennig, R; Pragst, F

2004-10-29

51

Analysis of ethyl glucuronide in human serum by capillary electrophoresis with sample self-stacking and indirect detection  

Microsoft Academic Search

Ethyl glucuronide (EtG), a metabolite of ethanol, is a marker of recent alcohol consumption. In the past few years, its analysis in body fluids has attracted considerable attention because it closes a gap between short time and long time alcohol markers such as ethanol and carbohydrate-deficient transferrin, respectively. The capillary zone electrophoresis (CZE) analysis of EtG in model mixtures and

L. K?ivánková; J. Caslavska; H. Malášková; P. Gebauer; W. Thormann

2005-01-01

52

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

53

SENSITIVITY AND SPECIFICITY OF URINARY ETHYL GLUCURONIDE AND ETHYL SULFATE IN LIVER DISEASE PATIENTS  

PubMed Central

Background It is important to monitor alcohol use in the care of liver disease patients, but patient self-report can be unreliable. We therefore evaluated the performance of urine ethyl glucuronide (EtG) and ethyl sulfate (EtS) in detecting alcohol use in the days preceding a clinical encounter. Methods Subjects (n=120) were recruited at a university-based Hepatology clinic or during hospitalization. Alcohol consumption was ascertained by validated self-report measures. Urine EtG (cutoff 100 ng/mL) and EtS (cutoff 25 ng/mL) concentrations were assayed by a contracted laboratory using tandem mass spectrometry. The sensitivity and specificity of each biomarker in the detection of drinking during the 3 and 7 days preceding the clinic visit were determined, as well as the influence of liver disease severity on these results. Results Urine EtG (sensitivity 76%, specificity 93%) and urine EtS (sensitivity 82%, specificity 86%) performed well in identifying recent drinking, and liver disease severity does not affect biomarker performance. After elimination of one false negative self-report, urine EtG > 100 ng/mL was 100% specific for drinking within the past week, whereas 9% of the subjects without evidence of alcohol drinking for at least one week had EtS > 25 ng/mL. Conclusions Urine EtG and EtS can objectively supplement the detection of recent alcohol use in patients with liver disease. Additional research may determine optimal methods for integrating these tests into clinical care.

Stewart, Scott H.; Koch, David G.; Burgess, Douglas M.; Willner, Ira R.; Reuben, Adrian

2012-01-01

54

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

55

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

56

Ethyl Glucuronide Discloses Recent Covert Alcohol Use Not Detected by Standard Testing in Forensic Psychiatric Inpatients  

Microsoft Academic Search

Background: Considerable lives and money could be saved if one could detect early stages of lapsing\\/ relapsing behavior in addicted persons (e.g., in safety-sensitive workplaces) and could disclose harmful drinking in social drinkers. Due to the serious public health problem of alcohol use and abuse worldwide, markers of alcohol use have been sought. Both ethyl glucuronide (EtG) and phosphatidyl ethanol

Friedrich Martin Wurst; Katja Jachau; Arthur Varga; Christer Alling; Andreas Alt; Gregory E. Skipper

2003-01-01

57

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

58

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

59

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

Microsoft Academic Search

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

Romina Shah; William R. LaCourse

2006-01-01

60

Ethyl glucuronide in human hair after daily consumption of 16 or 32 g of ethanol for 3 months  

Microsoft Academic Search

The overall objectives of the study were to develop a sensitive method for ethyl glucuronide (EtG) determination in hair and then investigate if a low or moderate intake of ethanol could be differentiated from total abstinence. Forty-four subjects were included in the study, 12 males (7 drinkers and 5 abstinent) and 32 females (14 drinkers and 18 abstinent). The study

Robert Kronstrand; Linda Brinkhagen; Fredrik H. Nyström

61

Influence of thermal hair straightening on ethyl glucuronide content in hair.  

PubMed

Hair analysis of ethyl glucuronide (EtG) has become a valuable marker for the detection of moderate and chronic alcohol consumption. It has been shown that bleaching and perming may decrease EtG content in hair. So far, no studies exist about the influence of thermal hair straightening on EtG content in hair. Forty-one positive EtG hair samples were treated in vitro with a hair straightener at 200°C. Duration of treatment of 1 min was chosen for this study. After washing, pulverization, incubation in ultrasonic bath, solid-phase extraction, and derivatization with heptafluorobutyric anhydride, EtG was determined by gas chromatography-mass spectrometry - negative ion chemical ionization (GC-MS-NICI). The EtG contents in straightened hair strands were then compared with those in the corresponding untreated strands. In 20 of 41 hair samples, a decrease of EtG content was found ranging from 0.7% to 79.3% (average 20%) whereas in 21 cases an increase was shown ranging from 2.0% to 50.9% (average 15%). The variation of the results seems to depend on hair colour. The decrease may be explained by thermic in vitro destruction of EtG. The increase may be explained by denaturation of the hair matrix by thermal treatment possibly causing a better extraction of EtG during incubation in ultrasonic bath. This in vitro study indicates that thermal hair straightening has an impact on the EtG content in hair. This has to be considered for a correct interpretation of EtG results in hair. However, these results should be confirmed by in vivo studies. PMID:24817051

Ettlinger, Jana; Kirchen, Luc; Yegles, Michel

2014-06-01

62

Identification and preliminary characterization of UDP-glucuronosyltransferases catalyzing formation of ethyl glucuronide.  

PubMed

Ethyl glucuronide (EtG), a minor metabolite of ethanol, is used as a marker of alcohol consumption in a variety of clinical and forensic settings. At present there are very few studies of UDP-glucuronosyltransferases (UGT), responsible for catalyzing EtG formation, and the possible effect of nutritional components, e.g. flavonoids, which are extensively glucuronidated, on EtG formation has not been addressed at all. The following incubation conditions were optimized with regard to previously published conditions: buffer, substrate concentration, and incubation time. Isolation of EtG from the incubation mixture was also optimized. Recombinant UGT enzymes (UGT1A1, 1A3, 1A4, 1A6, 1A9, 2B7, 2B10, 2B15) were screened for their activity towards ethanol, and kinetic data were then established for all enzymes. It was decided to study the effect of the flavonoids quercetin and kaempferol on glucuronidation of ethanol. Isolation was by solid-phase extraction (SPE) to minimize matrix effects. Analysis was performed by liquid chromatography-tandem mass spectrometry (LC-MS-MS), with EtG-d5 as the internal standard. SPE was vital to avoid severe ion suppression after direct injection of the incubation solution. EtG formation was observed for all enzymes under investigation; their kinetics followed the Michaelis-Menten model, meaning the maximum reaction rate achieved at saturating substrate concentrations (V(max)) and the substrate concentration at which the reaction rate is half of V(max) (Michaelis-Menten constant, K(m)) could be calculated. The highest rate of glucuronidation was observed with UGT1A9 and 2B7. After co-incubation with both flavonoids, formation of EtG was significantly reduced for all enzymes except for UGT2B15, whose activity did not seem to be affected. Results reveal that multiple UGT isoforms are capable of catalyzing glucuronidation of ethanol; nevertheless, the effect of UGT polymorphism on glucuronidation of ethanol needs further study. Formation of EtG is inhibited by the flavonoids under investigation. Obviously, nutritional components affect conversion of ethanol to EtG. This observation may serve as a partial explanation of its variable formation in man. PMID:24553666

Schwab, Nicole; Skopp, Gisela

2014-04-01

63

[Carbohydrate deficient transferrin and ethyl glucuronide: markers for alcohol use].  

PubMed

In this article, we report on the usefulness of physicians testing for carbohydrate deficient transferrin (CDT) and ethyl glucuronide (EtG) when there are doubts about alcohol use by their patients. A 44-year-old male consulted his general practitioner with depressive symptoms and denied using alcohol. Laboratory examination revealed an elevated CDT value. The latter was caused by chronic alcohol use. The second patient, a 32-year-old female with known alcohol dependence and receiving inpatient treatment at an addiction clinic, came back from leave. She denied having consumed alcohol and her blood alcohol concentration was zero. Examination of her urine showed an elevated EtG/creatinine ratio. This was caused by having had a few drinks during her leave and could not have been caused by using mouthwash or disinfection soap. We describe how to use the results of CDT and EtG testing in the therapeutic process and give recommendations for patient communication before performing these two tests. PMID:23739598

Paling, Erik P; Mostert, Leendert J

2013-01-01

64

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

65

Ethyl glucuronide in hair - A highly effective test for the monitoring of alcohol consumption.  

PubMed

In Germany drink driving offenders lose their license and must prove abstinence for one year in order to regain it. In this paper we assess the newly introduced ethyl glucuronide (EtG) tests in urine and hair in this alcohol abstinence monitoring. 20% (80 out of 386) of the 3cm long hair samples were tested positive for EtG in hair, compared to only 2% (92 out of 4248 samples) in urine in the same time period. Additionally 50% of the samples positive for EtG in hair had EtG values greater than 30pg/mg hair, indicating chronic alcohol consumption in the last three months. This study shows that four EtG tests in 3cm hair lengths reveal a significantly higher percentage of drink driving offenders who fail to be sober in the rehabilitation period, than do six random EtG tests in urine. Presumably, the hair test is more adequate to monitor long term alcohol abstinence than the urine test as defined by the new driving license re-granting medical and psychological assessment (MPA) in Germany. PMID:22019393

Agius, Ronald; Nadulski, Thomas; Kahl, Hans-Gerhard; Dufaux, Bertin

2012-05-10

66

A study of distribution of ethyl glucuronide in different keratin matrices.  

PubMed

Ethyl glucuronide (EtG) is a direct metabolite of ethanol, frequently used as a biomarker of alcohol abuse. To this purpose, EtG is preferentially determined in hair samples, using a cut-off value of 30pg/mg to discriminate between social and heavy drinkers, as recently fixed by an international consensus conference. Although this cut-off value is assumed for head hair, alternative matrices, such as pubic, axillary and chest hair, are often analyzed when head hair is not available. Previous studies suggested that determination of EtG in various keratin matrices may lead to different results; growth cycle and rate, urine contamination, distribution of sebum glands and other environmental factors are likely to contribute to these differences. We analyzed more than 2700 samples (head, pubic, chest and axillary hair) to evaluate the inter- and intra-individual distribution of the EtG concentration in the different keratin matrices. The data were interpreted on a statistical basis, on the assumption that large population data-sets will level off the average alcohol consumption of each group. From both inter- and intra-individual distribution data, significant differences were observed in EtG concentrations recorded in head, axillary and pubic hair samples. It is concluded that pubic hair cannot be utilized alternatively to head hair to prove chronic alcohol abuse, nor is axillary hair, since positive and negative biases respectively affect these determinations. In contrast, for chest hair, EtG distributions similar to head hair were found, although the large discrepancy between the examined population dimensions presently prevents any definitive conclusion. Thus, chest hair represents a promising alternative to head hair for EtG determinations, deserving further investigation on samples collected from the same individuals, in order to establish a clear correlation between their respective EtG concentrations. PMID:21511419

Pirro, V; Di Corcia, D; Pellegrino, S; Vincenti, M; Sciutteri, B; Salomone, A

2011-07-15

67

Population Baseline of Meconium Ethyl Glucuronide and Ethyl Sulfate Concentrations in Newborns of Nondrinking Women in 2 Mediterranean Cohorts.  

PubMed

The detection of ethyl glucuronide (EtG) and ethyl sulfate (EtS) in meconium has been investigated recently as an alternative to meconium fatty acid ethyl esters (FAEEs) measurement as an objective estimate of prenatal alcohol exposure, independent of maternal self-reporting. We report the results of the first study conducted to investigate the concentrations of EtG and EtS in meconium from newborns with and without intrauterine exposure to ethanol, defined by questionnaire and meconium FAEEs concentration. FAEEs, EtG, and EtS were quantified by liquid chromatography tandem mass spectrometry in meconium samples obtained from the Arcispedale Santa Maria Nuova, Reggio Emilia, Italy (n = 80) and from the Hospital del Mar in Barcelona, Spain (n = 105). Median EtG and EtS values in meconium from newborns without intrauterine exposure to ethanol varied between 0.100 and 0.140 nmol/g and 0.010 and 0.020 nmol/g in Reggio Emilia and Barcelona samples, respectively. In meconium from newborns with uncertain prenatal ethanol exposure, the EtG median value was 0.160 nmol/g in the Italian cohort and 0.250 nmol/g in the Spanish one. The median EtS concentration was 0.020 in both cohorts. EtG and EtS median values in 5 meconium samples from newborns of heavily drinking mothers were 7.240 nmol/g and 0.033 nmol/g, respectively. A positive cutoff of 2.0 nmol/g for EtG yielded the best sensitivity and specificity (100%) to discriminate for true prenatal exposure to ethanol. It was not possible to establish a proper cutoff for EtS because of the low number of positive samples. Based on our results, meconium EtG can be proposed as an alternate biomarker for intrauterine alcohol exposure. In contrast to the 7 FAEEs, EtG is just one molecule that could be screened in meconium samples from all newborns by a simple, low-cost, easy-to-perform immunoassay, which can be routinely applied in neonatology wards for the early diagnosis of prenatal exposure to ethanol. PMID:20335828

Morini, Luca; Groppi, Angelo; Marchei, Emilia; Vagnarelli, Federica; Garcia Algar, Oscar; Zuccaro, Piergiorgio; Pichini, Simona

2010-03-23

68

Ethyl-glucuronide and ethyl-sulfate in placental and fetal tissues by liquid chromatography coupled with tandem mass spectrometry.  

PubMed

The aim of this study was to develop a method for the determination of ethyl-glucuronide (EtG) and ethyl-sulfate (EtS), two direct ethanol metabolites, in early placental and fetal human tissues, as potential biomarkers of transplacental ethanol transfer from the mother to the fetus. Placental and fetal tissue samples were obtained from women undergoing voluntary termination of pregnancy at 12 weeks of gestation. Samples were deproteinized and directly injected into a liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) system. Limits of detection of 13.0 and 23.0 pmol/g and lower limits of quantification of 22.0 and 40.0 pmol/g were reached for EtG and EtS, respectively. Inter- and intraday imprecision and accuracy were always lower than 15%. The method was applied to 70 samples (35 placentas and 35 fetal tissues). Of 35 samples, 4 samples collected from 4 women tested positive for EtG and EtS, always showing higher concentrations for EtG. The placenta/fetal tissue ratio for EtG was 2.9 ± 0.9, whereas EtS showed a ratio of 1.7 ± 0.7. Preliminary results suggest that these metabolites are present in both tissues. Further studies should now corroborate the hypothesis, not yet confirmed, that transplacental transfer of ethanol takes place not only for the parent compound but also for EtG and EtS. PMID:21787742

Morini, Luca; Falcón, Maria; Pichini, Simona; Garcia-Algar, Oscar; Danesino, Paolo; Groppi, Angelo; Luna, Aurelio

2011-11-01

69

Determination of ethyl glucuronide, a minor metabolite of ethanol, in human serum by liquid chromatography–electrospray ionization mass spectrometry  

Microsoft Academic Search

A rapid and sensitive determination procedure using liquid chromatography–electrospray ionization mass spectrometry (LC–ESI-MS) has been developed for the determination of ethyl glucuronide (EtG) in human serum. Samples were precipitated with methanol, centrifuged and the supernatant was evaporated to dryness followed by reconstitution with distilled water. As mobile phase 30 mM ammonium acetate–acetonitrile (30:70, v\\/v) was utilized. The base peak observed

M Nishikawa; H Tsuchihashi; A Miki; M Katagi; G Schmitt; H Zimmer; Th Keller; R Aderjan

1999-01-01

70

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

71

Hair Ethyl Glucuronide is Highly Sensitive and Specific for Detecting Moderate-to-Heavy Drinking in Patients with Liver Disease  

PubMed Central

Aims: Hair ethyl glucuronide (EtG) is a promising biomarker of moderate-to-heavy alcohol consumption and may have utility in detecting and monitoring alcohol use in clinical populations where alcohol use is of particular importance. This study evaluated the relationship between hair EtG and drinking in patients with liver disease. Methods: The subjects (n = 200) were patients with liver disease who presented for care at a university medical center. Alcohol use during the 3 months preceding participation in the study was assessed, and a sample of hair was obtained for EtG testing. Classification of drinking status (any drinking or averaging at least 28 g per day) by hair EtG was evaluated, as well as the effects of liver disease severity and demographic and hair care factors. Results: The area under the receiver operating characteristic curve for detecting an average of 28 g or more per day during the prior 90 days was 0.93. The corresponding sensitivity and specificity of hair EtG ?8 pg/mg for averaging at least 28 g of ethanol per day were 92 and 87%, respectively. Cirrhosis and gender may have a modest influence on the relationship between drinking and hair EtG. Conclusion: Hair EtG was highly accurate in differentiating subjects with liver disease averaging at least 28 g of ethanol per day from abstainers and lighter drinkers.

Stewart, Scott H.; Koch, David G.; Willner, Ira R.; Randall, Patrick K.; Reuben, Adrian

2013-01-01

72

Determination of ethyl glucuronide in human hair by hydrophilic interaction liquid chromatography-tandem mass spectrometry.  

PubMed

Ethyl glucuronide (EtG) is a direct metabolite of ethanol and has been utilized as a marker for alcohol intake. This study presents development, validation and application of a new hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) method for the analysis of EtG in human hair samples. The linearity was assessed in the range of 5-2000 pg/mg hair, with a correlation coefficient of >0.99. The method was selective and sensitive, with a limit of detection (LOD) and limit of quantitation (LOQ) of 0.05 pg/mg and 0.18 pg/mg in hair, respectively. Differently from the extraction procedures in the literature, a fast and simple liquid-liquid method was used and highest recoveries and cleanest extracts were obtained. The method was successfully applied to 30 human hair samples which were taken from those who state they consume alcohol. EtG concentrations in the hair samples of alcohol users participated in this study, ranged between 1.34 and 82.73 pg/mg. From the concentration of EtG in hair strands 20 of the 30 subjects can be considered regular moderate drinkers. PMID:24112322

Yaldiz, Fadile; Daglioglu, Nebile; Hilal, Ahmet; Keten, Alper; Gülmen, Mete Korkut

2013-10-01

73

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

PubMed

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 determination of FAEE in hair. In this study we investigated the influence of a long-term hair treatment with EtOH containing lotion, on the EtG concentrations in hair. In this study 7 volunteer subjects (classified as either rare, social or heavy drinkers) treated the right side of their scalp every day during a one or two month period with a commercial hair tonic (Seborin), which contains 44.0% ethanol (vol%). Collection of hair specimens from both sides of the scalp was done one day before hair treatment, one week and one month after treatment (for 5 subjects also after two months of treatment). A hair segment of 3 centimeters (cm) was cut and then washed with water and acetone, and then pulverized. EtG was quantified by GC/MS after pulverization and 2h of ultrasonication in water, extraction by solid phase extraction using Oasis MAX columns and derivatization with HFBA. Measurements were done in negative chemical ionization mode using EtG-D5 as internal standard. Comparison of EtG concentration in the treated and in the non-treated hair specimens did not show any increase at the different dates of collection for the 7 subjects. In conclusion, these results show that there is no indication for an increase of EtG after use of ethanol containing hair cosmetics. PMID:22051770

Martins Ferreira, Liliane; Binz, Tina; Yegles, Michel

2012-05-10

74

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

75

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

76

Ethyl glucuronide findings in hair samples from the mummies of the Capuchin Catacombs of Palermo.  

PubMed

The Capuchin Catacombs of Palermo contain over 1800 preserved bodies: friars, priests and laypeople including men, women, and children. The bodies were accessible to family members who could visit the deceased and commemorate them through prayers. The "Sicily Mummy Project" analyzed hair samples from 38 mummies to determine the presence of ethyl glucuronide (EtG) using a routine procedure in our accredited laboratory of liquid chromatography coupled with mass spectrometry. The limit of quantification was 2.3 pg/mg. The hair samples were from 1.5 to 12 cm in length. All samples were analyzed in 2 segments (seg. A 0-3 cm and seg. B the remainder). Samples <4 cm in length were cut in half. In 31 out of 76 segments positive results were obtained for EtG, with concentrations between 2.5 and 531.3 pg/mg (mean 73.8, median 13.3 pg/mg). In 14 cases positive results were obtained for both segments. In one sample a positive result was obtained for segment A but not for segment B and in a further two samples only for segment B. The results indicate that EtG analyses can be performed on mummy hair samples even several hundred years after death to identify evidence for significant alcohol consumption during life. PMID:24053883

Musshoff, Frank; Brockmann, Christopher; Madea, Burkhard; Rosendahl, Wilfried; Piombino-Mascali, Dario

2013-10-10

77

Determination of ethyl glucuronide in hair: a rapid sample pretreatment involving simultaneous milling and extraction.  

PubMed

A combination of simultaneous milling and extraction known as micropulverized extraction was developed for the quantification of the alcohol marker ethyl glucuronide (EtG) in hair samples using a homogeneous reference material and a mixer mill. Best extraction results from 50 mg of hair were obtained with 2-mL plastic tubes containing two steel balls (? = 5 mm), 0.5 mL of water and with an oscillating frequency of 30 s(-1) over a period of 30 min. EtG was quantified employing a validated GC-MS procedure involving derivatization with pentafluoropropionic acid anhydride. This micropulverization procedure was compared with dry milling followed by separate aqueous extraction and with aqueous extraction after manual cutting to millimeter-size snippets. Micropulverization yielded 28.0?±?1.70 pg/mg and was seen to be superior to manually cutting (23.0?±?0.83 pg/mg) and equivalent to dry grinding (27.7?±?1.71 pg/mg) with regard to completeness of EtG extraction. The option to process up to 20 samples simultaneously makes micropulverization especially valuable for the high throughput of urgent samples. PMID:24221575

Mönch, Bettina; Becker, Roland; Nehls, Irene

2014-01-01

78

A comparison of two alcohol biomarkers in clinical practice: ethyl glucuronide versus ethyl sulfate.  

PubMed

This study compared the characteristics of two direct alcohol biomarkers, ethyl glucuronide and ethyl sulfate. Both biomarkers were analyzed from urine specimens submitted by 58 active duty service members at Walter Reed National Military Medical Center's Addiction Treatment Service. These 58 individuals, as a result of serial testing, submitted a total of 374 urine specimens for laboratory analysis. Of 374 specimens, the paired tests were most often negative (n = 295, 78.9%).The paired tests were both positive less frequently (n = 38, 10.2%). In an interesting development ethyl sulfate produced more positive results than ethyl glucuronide (n = 32, 8.6%). PMID:24074194

Lande, R Gregory; Marin, Barbara

2013-01-01

79

An evaluation of washing and extraction techniques in the analysis of ethyl glucuronide and fatty acid ethyl esters from hair samples.  

PubMed

Ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEEs) are alcohol metabolites measured in hair and are after a decade of research thought to be the best markers in hair to indicate alcoholism and abstinence Forensic Sci. Int. 218 (2012) 2. A great body of work concerning EtG and FAEEs detection in hair has been performed. However, no recent extensive comparison has been made concerning washing and extraction procedures. This work shows that the washing procedure of dichloromethane followed by a methanol rinse of the hair sample removes more than 16% of the FAEEs and 50% of the total EtG that is present in and on the hair. A review of ten washing protocols (where the removal is categorised: high, medium or low) showed that a relatively high percentage of FAEEs was removed and "medium" amount of EtG compared to the other washing protocols. This work shows promising results for the extraction of the FAEEs and the combined extraction of FAEEs and EtG by using 30min of sonication with methanol. More FAEEs were recovered from hair with methanol than with any other extraction solvent including the commonly used dimethyl sulfoxide/heptane mixture. When the sonication time was increased a higher percentage of transesterification of the FAEEs was observed, the extraction was "dirtier" as solids and a colour change was observed whereas the extraction efficiency did not increase. Therefore, washing the hair sample with dichloromethane and methanol followed by an addition of 1ml of methanol and sonication for 30min to extract the FAEEs and EtG from hair is recommended for FAEEs as well as for the combined analysis of EtG and FAEEs. A linear calibration curve (r(2)>0.99) was obtained for all analytes. PMID:24590191

Bossers, L C A M; Paul, R; Berry, A J; Kingston, R; Middendorp, C; Guwy, A J

2014-03-15

80

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

2012-09-01

81

Utility of urinary ethyl glucuronide analysis in post-mortem toxicology when investigating alcohol-related deaths.  

PubMed

Use and abuse of alcohol are common findings when unnatural deaths are investigated as evidenced by high blood- and urine- alcohol concentrations (BAC and UAC) at autopsy. Because ethanol is metabolized in the liver until the time of death, the autopsy BAC or UAC might be negative even though the deceased had consumed alcohol in the immediate ante-mortem period. Analysis of the non-oxidative metabolite of ethanol [ethyl glucuronide (EtG)] offers a more sensitive test of recent drinking. In this paper, we determined the concentrations of ethanol and EtG in urine samples from 972 consecutive forensic autopsies. In 425 cases (44%) both EtG and ethanol were positive, which supports ante-mortem drinking. In 342 cases (35%), both EtG and ethanol was negative, which speaks against any consumption of alcohol just before death. In 181cases, ethanol was negative in urine (<0.2g/kg), whereas EtG was positive (>0.5mg/L), which points towards ingestion of alcohol some time before death. In these cases, mean and median concentrations of EtG were 53.2mg/L and 23.7mg/L, respectively, although there was no mention of alcohol on 131 of the death certificates. Alcohol was mentioned on death certificates as an underlying or immediate cause of death or a contributing factor in 435 (45%) cases, which rose to 566 (58%) cases when positive EtG results were included. This article demonstrates the usefulness of EtG analysis in routine post-mortem toxicology when ante-mortem drinking and alcohol-related deaths are investigated. PMID:24954799

Sundström, M; Jones, A W; Ojanperä, I

2014-08-01

82

A comparison of the performance of quality controls prepared from spiked, fortified and authentic hair for ethyl glucuronide analysis.  

PubMed

Ethyl glucuronide (EtG) quantification in hair was assessed using quality controls prepared by three methods: (a) spiking hair samples with known concentrations of EtG, (b) fortifying hair by incubation of blank hair with EtG for several days or (c) use of authentic hair samples positive for EtG. A liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed on a Shimadzu model 8030 instrument and validated for the quantification of EtG. For two concentration levels, approximately 50 and 500 pg/mg QCs, EtG concentrations were measured in duplicate (N=2) on 8 days (N=16) and intra-assay precision (repeatability) and inter-assay precision determined using one-way analysis of variance. EtG concentrations measured in authentic hair exhibited poor intra-assay precision, with coefficients of variation of 25.1 and 20.9%, compared with 17.7 and 18.5% for fortified hair and 17.4 and 11.3% for spiked hair, for the lower and higher concentrations respectively. The inter-assay precision for authentic hair was also poorer, 35.7 and 22.5%, compared with fortified (28.2 and 19.8%) and spiked (18.4 and 13.2%) hair for the lower and higher concentrations. Although spiked QCs resulted in a better repeatability and inter-assay precision, the values obtained for QCs prepared from fortified and authentic hair are likely to be more representative of case specimens. These results have implications on the interpretation of EtG concentrations when spiked QCs are used to validate methods. PMID:24053866

Turfus, Sophie C; Beyer, Jochen; Gerostamoulos, Dimitri; Drummer, Olaf H

2013-10-10

83

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

2013-03-10

84

Ethyl sulphate and ethyl glucuronide in vitreous humor as postmortem evidence marker for ethanol consumption prior to death.  

PubMed

To clarify the circumstances of death, the degree of inebriation is of importance in many cases, but for several reasons the determination of the ethanol concentration in post-mortem samples can be challenging and the synopsis of ethanol and the direct consumption markers ethyl glucuronide (EtG) and ethyl sulphate (EtS) has proved to be useful. The use of a rather stable matrix like vitreous humor offers further advantages. The aim of this study was to determine the concentrations of ethanol and the biomarkers in the robust matrix of vitreous humor and to compare them with the respective levels in peripheral venous blood and urine. Samples of urine, blood from the femoral vein and vitreous humor were taken from 26 deceased with suspected ethanol consumption prior to death and analyzed for ethanol, EtS and EtG. In the urine samples creatinine was also determined. The personal data, the circumstances of death, the post-mortem interval and the information about ethanol consumption prior to death were recorded. EtG and EtS analysis in urine was performed by LC-ESI-MS/MS, creatinine concentration was determined using the Jaffé reaction and ethanol was detected by HS-GC-FID and by an ADH-based method. In general, the highest concentrations of the analytes were found in urine and showed statistical significance. The mean concentrations of EtG were 62.8mg/L (EtG100 206.5mg/L) in urine, 4.3mg/L in blood and 2.1mg/L in vitreous humor. EtS was found in the following mean concentrations: 54.6mg/L in urine (EtS100 123.1mg/L), 1.8mg/L in blood and 0.9mg/L in vitreous humor. Ethanol was detected in more vitreous humor samples (mean concentration 2.0g/kg) than in blood and urine (mean concentration 1.6g/kg and 2.1g/kg respectively). There was no correlation between the ethanol and the marker concentrations and no statistical conclusions could be drawn between the markers and matrices. PMID:21367549

Thierauf, Annette; Kempf, Jürgen; Perdekamp, Markus Grosse; Auwärter, Volker; Gnann, Heike; Wohlfarth, Ariane; Weinmann, Wolfgang

2011-07-15

85

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

86

Do drug users use less alcohol than non-drug users? A comparison of ethyl glucuronide concentrations in hair between the two groups in medico-legal cases  

Microsoft Academic Search

Two groups were selected from the remainder of hair samples that had been tested for drugs at TrichoTech for medico-legal cases: samples that tested negative (drug-negative group; N=42, age 33.4±7.2 years) and samples that tested positive for drugs (drug-positive group; N=57, age 32.5±8.8 years).A rapid, simple method to detect the ethanol metabolite, ethyl glucuronide (EtG) in hair has been developed.

Richard Paul; Robert Kingston; Lolita Tsanaclis; Anthony Berry; Alan Guwy

2008-01-01

87

Ethyl glucuronide concentrations in two successive urinary voids from drinking drivers: relationship to creatinine content and blood and urine ethanol concentrations  

Microsoft Academic Search

The concentrations of alcohol in blood (BAC) and two successive urine voids (UAC) from 100 drunk drivers were compared with the concentration of ethyl glucuronide (EtG), a minor metabolite of ethanol in urine, and the urinary creatinine content as an indicator of dilution. The subjects consisted of 87 men with mean age 42.2±14.2 years (±standard deviation, S.D.) and 13 women

J Bergström; A Helander; A. W Jones

2003-01-01

88

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

2012-05-10

89

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

PubMed

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 and hair. For each matrix, the sample preparation and the chromatographic separation were thoroughly optimised. Additionally, experiments with reversed-phase liquid chromatography were also performed in the development stages. Analyses were carried out using a Phenomenex Luna HILIC column (150 mm x 3 mm, 5 microm) and a mobile phase composed by ammonium acetate 2mM and acetonitrile, in gradient. Different SPE cartridges (Oasis MAX, Oasis WAX, aminopropyl silica) and solvents were tested in order to obtain the highest recoveries and cleanest extracts. Optimal results were obtained for meconium with aminopropyl cartridges, while for hair an incubation of 16 h with 2 mL of water and acetonitrile (50/50, v/v) provided good results. The analytical method was validated for both matrices (meconium and hair) by assessing linearity, precision, accuracy, recovery and limit of quantification. The calibration curve concentrations ranged from 50 to 1200 pg/mg for meconium and from 20 to 1000 pg/mg for hair. Real meconium and hair samples were analyzed and results were consistent with literature. PMID:20061101

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

2010-03-20

90

Improved liquid chromatography-tandem mass spectrometric method for the determination of ethyl glucuronide concentrations in hair: applications to forensic cases.  

PubMed

Ethyl glucuronide (EtG) is a direct marker of ethanol consumption, and its assay in hair is an efficient tool for chronic alcoholism diagnosis. In 2012, the Society of Hair Testing proposed a new consensus for hair concentrations interpretation, strongly advising the use of analytical methods providing a limit of quantification of less than 3 pg/mg. The present work describes the optimization and validation of a previously developed liquid chromatography-tandem mass spectrometric method in order to comply with this recommendation. The concentration range of this improved method is from 3 to 1,000 pg/mg. Some cases are then described to illustrate the usefulness of hair EtG: a forensic post-mortem case and two cases of suspension of driving licences. Finally, hair samples of some teetotallers (n?=?10) have been analyzed, which allowed neither to quantitate nor to detect any trace of EtG. PMID:23824336

Imbert, Laurent; Gaulier, Jean-Michel; Dulaurent, Sylvain; Morichon, Julien; Bevalot, Fabien; Izac, Paul; Lachâtre, Gérard

2014-01-01

91

Validation of a novel method to identify in utero ethanol exposure: simultaneous meconium extraction of fatty acid ethyl esters, ethyl glucuronide, and ethyl sulfate followed by LC-MS/MS quantification.  

PubMed

Presence of fatty acid ethyl esters (FAEE), ethyl glucuronide (EtG), and ethyl sulfate (EtS) in meconium, the first neonatal feces, identifies maternal alcohol consumption during pregnancy. Current meconium alcohol marker assays require separate analyses for FAEE and EtG/EtS. We describe development and validation of the first quantitative liquid chromatography tandem mass spectrometry assay for 9 FAEEs, EtG, and EtS in 100 mg meconium. For the first time, these alcohol markers are analyzed in the same meconium aliquot, enabling comparison of the efficiency of gestational ethanol exposure detection. 100 mg meconium was homogenized in methanol and centrifuged. The supernatant was divided, and applied to two different solid phase extraction columns for optimized analyte recovery. Limits of quantification for ethyl laurate, myristate, linolenate, palmitoleate, arachidonate, linoleate, palmitate, oleate, and stearate ranged from 25-50 ng/g, with calibration curves to 2,500-5,000 ng/g. EtG and EtS linear dynamic ranges were 5-1,000 and 2.5-500 ng/g, respectively. Mean bias and between-day imprecision were <15 %. Extraction efficiencies were 51.2-96.5 %. Matrix effects ranged from -84.7 to 16.0 %, but were compensated for by matched deuterated internal standards when available. All analytes were stable (within ±20 % change from baseline) in 3 authentic positive specimens, analyzed in triplicate, after 3 freeze/thaw cycles (-20 °C). Authentic EtG and EtS also were stable after 12 h at room temperature and 72 h at 4 °C; some FAEE showed instability under these conditions, although there was large inter-subject variability. This novel method accurately detects multiple alcohol meconium markers and enables comparison of markers for maternal alcohol consumption. PMID:24408304

Himes, Sarah K; Concheiro, Marta; Scheidweiler, Karl B; Huestis, Marilyn A

2014-03-01

92

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

93

A kinetic model describing the pharmacokinetics of ethyl glucuronide in humans  

Microsoft Academic Search

The glucuronide conjugation is a minor pathway of ethanol metabolism. The determination of ethyl glucuronide (EG) in serum and urine has gained importance in forensic and other legal decisions. To prospectively calculate the serum concentration of this non-oxidative ethanol metabolite, the computer program developed includes a parameter fitting routine. Multiple ethanol doses can be handled.The mathematical modeling was based on

Peter Droenner; Georg Schmitt; Rolf Aderjan; Holger Zimmer

2002-01-01

94

Detection of ethyl glucuronide in dried human blood using LCMS\\/MS  

Microsoft Academic Search

Ethyl glucuronide, as a direct metabolite of ethanol degradation, has proven useful as a long-term marker in many forensic\\u000a applications. The inability to determine ethyl glucuronide in dried blood left a missing link in many investigations. Here,\\u000a we describe a new method based on mass spectrometry in a Pauli-type ion trap in order to determine this substance in dried\\u000a blood

Eckhard Kaufmann; Andreas Alt

2008-01-01

95

Measurement of ethyl glucuronide, ethyl sulphate and their ratio in the urine and serum of healthy volunteers after two doses of alcohol.  

PubMed

Aims: Ethyl glucuronide (EtG) and ethyl sulphate (EtS) are minor metabolites of ethanol, and their presence in urine provides a strong indication of recent alcohol administration. In this study, we performed a drinking experiment to investigate the kinetics of EtG and EtS formation and elimination after the administration of two doses of alcohol. Methods: Nineteen volunteers provided urine and serum (only 18) after administration of 4 and 8 units of alcohol (1 unit corresponds to 10 ml or ?8 g of pure ethanol). The analysis was performed using a validated ultra-performance liquid chromatography-mass spectrometry (UPLC(®)-MS/MS) method. Results: After 4 units, the median EtG maximum concentration (C(max)) was 0.4 µg/ml and the interquartile range (0.3 µg/ml) in serum and 3.5 mg/h (1.2 mg/h) in urine and were reached (T(max)) after 2.0 h (0.8 h) and 3.0 h (1.0 h), respectively. EtS C(max) was 0.2 µg/ml (0.1 µg/ml) in serum and 1.3 mg/h (0.6 mg/h) in urine, and the corresponding T(max) were 1.0 h (1.0 h) and 2.0 h (0.5 h). After 8 units, EtG C(max) was 1.3 µg/ml (0.4 µg/ml) in serum and 10 mg/h (3.4 mg/h) in urine and was reached after 4.0 h (1.8 h) and 4.0 h (2.0 h), respectively. EtS C(max) was 0.6 µg/ml (0.1 µg/ml) in serum and 3.5 mg/h (1.1 mg/h) in urine, the corresponding T(max) were 3.0 h (1.0 h) and 3.0 h (1.0 h). The EtG/EtS ratio increased as a function of the time after alcohol administration in both serum and urine samples but to a lesser extent after 8 units than 4. Conclusion: These results correlate with values obtained in previous studies. T(max) of EtG and EtS increased between 4 and 8 units. The EtG:EtS ratio increased in the serum and urine samples of all volunteers as a function of time at least up to 4 h after alcohol administration. PMID:23043120

Lostia, Alfonso Maria; Vicente, Joana Lobo; Cowan, David A

2013-01-01

96

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

PubMed

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 clinical parameters such as ALT, AST, gammaGT and CDT (asialotransferrin and disialotransferrin) are in the normal range and EtG in urine negative. In this paper, we describe the development, optimization and validation of a new method based on hair extraction with water, clean-up by solid phase extraction (SPE), derivatization with heptafluorobutyric anhydride and headspace solid-phase microextraction (HS-SPME) in combination with GC-MS/MS according to forensic guidelines. The assay linearity of EtG was confirmed over the range from 2.8 to 1000 pg/mg hair, with a coefficient of determination (r(2)) above 0.999. The LLOQ was 2.8 pg/mg and the LLOD was 0.6 pg/mg. An error profile calculated according to the "Guide to the Expression of Uncertainty in Measurement" (GUM) at 99% confidence intervals for the range 5-750 pg/mg hair did not exceed 10%. This range corresponds to more than 98% of the positive samples analysed. PMID:20061100

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

2010-03-20

97

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

2012-02-01

98

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

2013-07-01

99

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

100

Glucuronic acid and the ethanol metabolite ethyl-glucuronide cause Toll-like receptor 4 activation and enhanced pain  

PubMed Central

We have previously observed that the non-opioid morphine metabolite, morphine-3-glucuronide, enhances pain via a toll-like receptor 4 (TLR4) dependent mechanism. The present studies were undertaken to determine whether TLR4-dependent pain enhancement generalizes to other classes of glucuronide metabolites. In silico modeling predicted that glucuronic acid alone and ethyl glucuronide, a minor but long-lasting ethanol metabolite, would dock to the same MD-2 portion of the TLR4 receptor complex previously characterized as the docking site for morphine-3-glucuronide. Glucuronic acid, ethyl glucuronide and ethanol all caused an increase in TLR4-dependent reporter protein expression in a cell line transfected with TLR4 and associated co-signaling molecules. Glucuronic acid-, ethyl glucuronide-, and ethanol-induced increases in TLR4 signaling were blocked by the TLR4 antagonists LPS-RS and (+)-naloxone. Glucuronic acid and ethyl glucuronide both caused allodynia following intrathecal injection in rats, which was blocked by intrathecal co-administration of the TLR4 antagonist LPS-RS. The finding that ethyl glucuronide can cause TLR4-dependent pain could have implications for human conditions such as hangover headache and alcohol withdrawal hyperalgesia, as well as suggesting that other classes of glucuronide metabolites could have similar effects.

Lewis, Susannah S.; Hutchinson, Mark R.; Zhang, Yingning; Hund, Dana K.; Maier, Steven F.; Rice, Kenner C.; Watkins, Linda R.

2013-01-01

101

Glucuronic acid and the ethanol metabolite ethyl-glucuronide cause toll-like receptor 4 activation and enhanced pain.  

PubMed

We have previously observed that the non-opioid morphine metabolite, morphine-3-glucuronide, enhances pain via a toll-like receptor 4 (TLR4) dependent mechanism. The present studies were undertaken to determine whether TLR4-dependent pain enhancement generalizes to other classes of glucuronide metabolites. In silico modeling predicted that glucuronic acid alone and ethyl glucuronide, a minor but long-lasting ethanol metabolite, would dock to the same MD-2 portion of the TLR4 receptor complex previously characterized as the docking site for morphine-3-glucuronide. Glucuronic acid, ethyl glucuronide and ethanol all caused an increase in TLR4-dependent reporter protein expression in a cell line transfected with TLR4 and associated co-signaling molecules. Glucuronic acid-, ethyl glucuronide-, and ethanol-induced increases in TLR4 signaling were blocked by the TLR4 antagonists LPS-RS and (+)-naloxone. Glucuronic acid and ethyl glucuronide both caused allodynia following intrathecal injection in rats, which was blocked by intrathecal co-administration of the TLR4 antagonist LPS-RS. The finding that ethyl glucuronide can cause TLR4-dependent pain could have implications for human conditions such as hangover headache and alcohol withdrawal hyperalgesia, as well as suggesting that other classes of glucuronide metabolites could have similar effects. PMID:23348028

Lewis, Susannah S; Hutchinson, Mark R; Zhang, Yingning; Hund, Dana K; Maier, Steven F; Rice, Kenner C; Watkins, Linda R

2013-05-01

102

Effect of bleaching on ethyl glucuronide in hair: An in vitro experiment  

Microsoft Academic Search

IntroductionEthyl glucuronide in hair (HEtG) has recently gained great attention, because of its high sensitivity and specificity in the diagnosis of chronic alcohol abuse. Due to its high polarity hydrophilicity, a strong hair treatment followed by a shampooing may lead to removal\\/degradation of this molecule from hair matrix.

Luca Morini; Alessandra Zucchella; Aldo Polettini; Lucia Politi; Angelo Groppi

2010-01-01

103

Can ethyl glucuronide in hair be determined only in 3 cm hair strands?  

PubMed

This paper addresses the suitability of ethyl glucuronide in hair (EtGH) strands other than 3cm for alcohol consumption. This issue will be addressed (a) by statistically comparing the distribution of EtGH results for 3cm hair strands to other hair strands analysed from 4126 cases and (b) by examining the stability of EtGH in an 8cm hair strand and two 12cm hair samples of two volunteers and a post-mortem case using 1cm segmental analysis. For 3464 driving license re-granting Medical and Psychological Assessment (MPA) cases, the detection of alcohol consumption using hair lengths longer than 3cm was never significantly less than for 3cm hair lengths, even up to 12cm hair lengths analysed non-segmented. For 662 non-MPA cases, where, in contrast to MPA cases, generally no abstinence was required, an increase in the EtGH positivity rate was observed with increasing hair length analysed up to 9cm, indicating that EtG-washout effects seem to play a minor role if any. For both MPA and non-MPA hair samples less than 3cm, a drastic, significant increase in the number of positive EtGH samples were observed, compared to 3cm hair lengths, strongly supportive of EtGH incorporation from sweat after a recent alcohol consumption. Segmental studies indicated that EtG is stable in the hair matrix up to 12cm long, hence supporting the above results. Even though both the statistical and the stability studies are preliminary results which need to be confirmed by other studies, they both provide evidence for the determination of alcohol consumption using EtGH in hair lengths longer than 3cm. Amendments to the Consensus of the Society of Hair Testing, the German driving license re-granting guidelines and EWDTS hair guidelines with respect to testing for abstinence and/or alcoholism are proposed for the benefit of the donors. PMID:22019395

Agius, Ronald; Ferreira, Liliane Martins; Yegles, Michel

2012-05-10

104

A fully validated method for the quantification of ethyl glucuronide and ethyl sulphate in urine by UPLC-ESI-MS/MS applied in a prospective alcohol self-monitoring study.  

PubMed

A method for the quantification of ethyl glucuronide (EtG) and ethyl sulphate (EtS) in human urine is developed and fully validated according to international guidelines. Protein precipitation is used as sample preparation. During the development of the method on an UPLC-ESI-MS/MS system using a CSH C18 column, special attention was paid to reduce matrix effects to improve assay sensitivity and to improve detection of the second transition for EtS for specificity purposes. The method was linear from 0.1 to 10?g/mL for both analytes. Ion suppression less than 24% (RSD<15%) was observed for EtG and no significant matrix effect was measured for EtS. The recovery was around 80% (RSD<14%) for both compounds. This method provides good precision (RSDr and RSDt<10%) and bias (<15%) for internal and external quality control samples. The reproducibility of the method was demonstrated by the successful participation to proficiency tests (z-score<0.86). This method was finally used to analyze urine samples obtained from twenty-seven volunteers whose alcohol consumption during the 5 days before sampling was monitored. Concentrations between 0.5 and 101.9?g/mL (mean 10.9, median 1.4) for EtG and between 0.1 and 37.9?g/mL (mean 3.6, median 0.3) for EtS were detected in urine samples of volunteers who declared having consumed alcohol the day before the sampling. EtG and EtS concentrations in urine were highly correlated (r=0.996, p<0.001). A moderate correlation between the number of drinks the day before sampling and the concentration of EtG (r=0.448, p<0.02) or EtS (r=0.406, p<0.04) was observed. Using a cut-off value at 0.1?g/mL for EtG and EtS, this method is able to detect social alcohol consumption approximately 24h after the intake, without showing any false positive result. PMID:23685426

Kummer, Natalie; Wille, Sarah; Di Fazio, Vincent; Lambert, Willy; Samyn, Nele

2013-06-15

105

Simultaneous determination of GHB and EtG in hair using GCMS/MS.  

PubMed

A gas chromatographic tandem mass spectrometric (GCMS/MS) method for simultaneously determining trace concentrations of gamma-hydroxybutyrate (GHB) and ethyl glucuronide (EtG) in hair has been developed. Multiple reaction monitoring (MRM) was used to detect precursor and product ions of GHB, (233 and 147) and EtG (261 and 143) following anion exchange solid phase extraction and derivatization with N,O-bis[trimethylsilyl]trifluoroacetamide (BSTFA). Deuterated standards of GHB and EtG were used as internal standards. The assay produced excellent linearity (r(2) > 0.99) and sensitivity. The lower limit of quantitation (LLOQ) was 10 pg/mg for EtG assuming a 20 mg hair sample. The method has been used to investigate cases of suspected drug facilitated assault as well as being used to identify heavy alcohol consumption in a group of volunteers. PMID:21500364

Paul, R; Tsanaclis, L; Kingston, R; Berry, A; Guwy, A

2011-04-01

106

Determination of ethyl glucuronide levels in hair for the assessment of alcohol abstinence.  

PubMed

This study examined the potential of a highly sensitive LC-MS/MS method for the determination of EtG in head hair (i) to ascertain alcohol abstinence, (ii) to estimate the basal level of EtG (sub-ppb concentrations) in head hair in a population of alcohol abstainers and (iii) to suggest a revision of cut-off values for assessing alcohol abstinence. An UHPLC-MS/MS protocol previously developed was modified and validated again to detect low EtG levels in head hair samples from a population of 44 certain abstainers and teetotalers. Basal level of EtG in hair was determined by a standard addition quantification method. The validated UHPLC-MS/MS method allowed detecting and quantifying 0.5 and 1.0 pg/mg of EtG in hair, respectively. EtG concentrations lower than 1.0 pg/mg were determined for 95% of abstainers; 30% of them had non-detectable (<0.5 pg/mg) EtG values. Two samples evidenced EtG concentrations higher than 1.0 pg/mg that were subsequently explained by unintentional ethanol exposure. The method's feature of high analytical sensitivity makes it particularly suitable for alcohol abstinence ascertainment and, in the same time, allows to tentatively estimate basal EtG concentrations in hair around 0.8±0.4 pg/mg. This finding opens a discussion on the possible origin of basal EtG concentration and potential sources of bias in the evaluation of alcohol abstinence. Cut-off value in the range of 1.0-2.0 pg/mg can be reliably proposed to support alcohol abstinence. PMID:24053885

Pirro, V; Di Corcia, D; Seganti, F; Salomone, A; Vincenti, M

2013-10-10

107

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

PubMed

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 a hair lotion on a regularly base. To evaluate a possible effect of the hair lotion, prospective blood and urine controls as well as hair sampling of scalp and pubic hair were performed. The traditional clinical biomarkers of ethanol consumption, CDT and GGT, were inconspicuous in three blood samples taken. EtG was not detected in all collected urine samples. The hair lotion was transmitted to our laboratory. The ethanol concentration in this lotion was determined with 35g/L. The EtG immunoassay gave a positive result indicating EtG, which could be confirmed by GC-MS/MS-NCI. In a follow-up experiment the lotion was applied to the hair of a volunteer over a period of six weeks. After this treatment, EtG could be measured in the hair at a concentration of 72pg/mg suggesting chronic and excessive alcohol consumption. Overnight incubation of EtG free hair in the lotion yielded an EtG concentration of 140pg/mg. In the present case, the positive EtG hair findings could be interpreted as the result of an EtG containing hair care product. To our knowledge, the existence of such a product has not yet been reported, and it is exceptionally unusual to find EtG in cosmetics. Therefore, external sources for hair contamination should always be taken into account when unusual cosmetic treatment is mentioned. In those cases, it is recommended to analyze the hair product for a possible contamination with EtG. The analysis of body hair can help to reveal problems occurring from cosmetic treatment of head hair. As a consequence, the assessment of drinking behavior should be based on more than one diagnostic parameter. PMID:22018742

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

2012-05-10

108

Comparison of ethyl glucuronide in hair with carbohydrate-deficient transferrin in serum as markers of chronic high levels of alcohol consumption  

Microsoft Academic Search

This study was designed with the aim to compare sensitivity and specificity of ethyl glucuronide in hair (HEtG) and carbohydrate-deficient transferrin (CDT) in serum as markers of heavy drinking. Eighty-six volunteers, including teetotalers, social, and heavy drinkers, were interviewed to evaluate their ethanol daily intake (EDI) during the last 2-week and 3-month periods. HEtG determination was performed by a fully

Luca Morini; Lucia Politi; Silvia Acito; Angelo Groppi; Aldo Polettini

2009-01-01

109

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

2013-03-01

110

Ethyl glucuronide concentration in hair for detecting heavy drinking and/or abstinence: a meta-analysis.  

PubMed

In both clinical and forensic settings, hair analysis for ethyl glucuronide (HEtG) has been increasingly employed for diagnosing chronic excessive drinking and, more recently, for monitoring abstinence. This paper aims at meta-analysing published data on HEtG concentrations in teetotallers, social drinkers and heavy drinkers in order to evaluate the use of this marker in hair for identifying chronic excessive drinking and for monitoring abstinence. In May 2012, a systematic multi-database search retrieved 366 records related to HEtG and further screened for relevant publications in the field. Fifteen (4.1 %) records matched the selection criteria and were included in the meta-analysis. The mean and 95 % confidence intervals (CI) of HEtG concentrations in social drinkers (mean 7.5 pg/mg; 95 % CI 4.7-10.2 pg/mg; p < 0.001), heavy drinkers (mean 142.7 pg/mg; 95 % CI 99.9-185.5 pg/mg; p < 0.001) and deceased subjects with a known history of chronic excessive drinking (mean 586.1 pg/mg; 95 % CI 177.2-995.0 pg/mg; p < 0.01) were calculated. The ranges of mean values and 95 % confidence intervals for single studies involving teetotallers/social or social/heavy drinkers showed a partial overlap with a down-trespassing of both the 7 and 30 pg/mg thresholds for social and heavy drinkers, respectively. Although larger and well-designed population studies are required to draw any definitive conclusion, our data show that the cut-off of 30 pg/mg limits the false-negative effect in differentiating heavy from social drinkers, whereas the recently proposed 7 pg/mg cut-off value might only be used for suspecting an active alcohol use, and not for proving complete abstinence. PMID:23250386

Boscolo-Berto, Rafael; Viel, Guido; Montisci, Massimo; Terranova, Claudio; Favretto, Donata; Ferrara, Santo Davide

2013-05-01

111

Serum/whole blood concentration ratio for ethylglucuronide and ethyl sulfate.  

PubMed

Serum/blood (S/B) concentration ratios for ethyl glucuronide (EtG) and ethyl sulfate (EtS) are missing from the literature, and the aim of this study was to determine these ratios in samples from patients at admission to an alcohol rehabilitation clinic. Two blood samples were collected simultaneously, and EtG and EtS were analyzed in whole blood and serum, respectively, using a liquid chromatography-mass spectrometry method. Separate calibration standards were prepared in both whole blood and serum for the calculation of whole blood and serum concentrations, respectively. Thirteen pairs of serum and whole blood were analyzed. The median S/B value for EtG was 1.69, and the range was 1.33-1.90. For EtS, the median S/B ratio was 1.30, and the range was 1.08-1.47. The S/B ratio was significantly lower for EtS than for EtG (p < 0.001). The higher concentrations of EtG and EtS in serum than in whole blood have to be considered when whole blood results obtained from forensic toxicology are compared to serum or plasma results from clinical laboratories. PMID:19470223

Høiseth, Gudrun; Morini, Luca; Polettini, Aldo; Christophersen, Asbjørg S; Johnsen, Lene; Karinen, Ritva; Mørland, Jørg

2009-05-01

112

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

113

Gyrokinetic Simulations of ETG and ITG Turbulence.  

National Technical Information Service (NTIS)

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-...

A. M. Dimits D. E. Shumaker G. W. Hammett T. Dannert W. M. Nevins

2006-01-01

114

Gyrokinetic simulations of ETG and ITG turbulence  

Microsoft Academic Search

We report on the resolution of a significant discrepancy between published continuum-code simulations and subsequent global particle-in-cell (PIC) simulations of electron-temperature-gradient (ETG) turbulence. Our investigations, using gyrokinetic deltaf-PIC- and continuum-code simulations and analytical theory, strongly support the conclusion from the earlier continuum-code simulations that ETG turbulence can drive the electron thermal conductivity chie large enough to be significant in some

A. M. Dimits; W. M. Nevins; D. E. Shumaker; G. W. Hammett; T. Dannert; F. Jenko; M. J. Pueschel; W. Dorland; S. C. Cowley; J. N. Leboeuf; T. L. Rhodes; J. Candy; C. Estrada-Mila

2007-01-01

115

Coupled ITG/TEM-ETG Gyrokinetic Simulations  

NASA Astrophysics Data System (ADS)

Electron temperature gradient (ETG) transport is conventionally defined as the electron energy transport from high-k where ions are adiabatic and there can be no ion energy or plasma transport. Previous simulations have assumed adiabatic ions (ETG-ai). However using the GYRO gyrokinetic code [1], we have found that many simulation cases with trapped electron at moderate shear do not nonlinearly saturate unless fully kinetic ions and some low-k ion scale zonal flow modes are included. We define high-k ETG-ki transport to be that arising from ky?s-i> 1 including electron gyroradius scales ky?s-e˜1, and ion temperature gradient and trapped electron mode (ITG/TEM) transport to be that from ky?s-i<=1. There has been speculation [2] that ETG transport could be modified by the nonlinear coupling to the ITG/TEM turbulence (or vise-versa). We have done very expensive high Reynold's number (k-max/k-min)^2(?s-i/?s-e)^2=2? high-resolution-large-flux-tube simulations with coupled ITG/TEM-ETG-ki turbulence. By comparing expensive simulations with much cheaper uncoupled high-resolution-small-flux-tube ETG-ki and low-resolution-large-flux-tube ITG/TEM simulations, we hope to demonstrate that superposition of the cheaper simulations is sufficiently accurate. Electron energy transport from ETG-ki is 5-10 fold smaller than from ITG/TEM except when the ExB shear is strong enough to quenched the low-k transport. GYRO compute time for the expensive simulations scales as ˜&3-4circ;. Reduced mass ratio ?=20 simulations have been done, and ?=30 simulations in progress accurately represent the ?=,40-60 physical range. 6pt [1] J. Candy and R.E. Waltz, Phys. Rev. Lett. 91 (2003) 045001. [2] C. Holland and P.H. Diamond, Phys. Plasmas 11 (2004) 1043.

Waltz, R. E.

2006-10-01

116

Nonlinear Saturation Physics of the ETG Modes  

NASA Astrophysics Data System (ADS)

Production and identification of electron temperature gradient (ETG) mode and the measurement of electron thermal conductivity due to it have been successfully done in a basic experiment in Columbia Linear Machine CLM [1,2]. Now we report the nonlinear saturation mechanism of the ETG modes. The bi-coherence experimental data shows coupling between two high frequency (˜2MHz) and one low frequency (˜40kHz) modes. The 3-wave coupling model (two radial harmonics ETG and one ion acoustic mode) yielded a theoretical saturation level of ETG mode ˜5 %, which roughly agrees with experiments. The role of ion acoustic mode in the saturation of ETG mode has also been experimentally demonstrated by using unique feedback techniques. 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] V. Sokolov, A.K. Sen, APS DPP10, TP9.00022

Sokolov, Vladimir; Tokluoglu, E.; Sen, A. K.

2011-11-01

117

Gyrokinetic simulations of ETG and ITG turbulence  

NASA Astrophysics Data System (ADS)

We report on the resolution of a significant discrepancy between published continuum-code simulations and subsequent global particle-in-cell (PIC) simulations of electron-temperature-gradient (ETG) turbulence. Our investigations, using gyrokinetic ?f-PIC- and continuum-code simulations and analytical theory, strongly support the conclusion from the earlier continuum-code simulations that ETG turbulence can drive the electron thermal conductivity ?e large enough to be significant in some tokamaks. A successful ETG-turbulence benchmark between ?f-PIC and continuum codes for ETG turbulence has also been completed. Scans in the magnetic shear show an abrupt transition to a high-?e state as the shear is increased from the benchmark value of s = 0.1 to above s = 0.4. When nonadiabatic ions are used, this abrupt transition is absent, and ?e reaches values consistent with transport analyses of DIII-D, JET, JT60-U and NSTX discharges. The balances of zonal-flow driving and damping terms in late-time quasi-steady phase of ITG turbulence have been unfolded using a new run-time gyrokinetic-simulation diagnostic. The zonal flow level is set by a balance of large driving and damping terms which almost cancel each other. The driving is found to be mostly by the Reynolds stress, while the dissipation is mostly by the linear (transit-time) damping terms. It is also shown that useful zonal-flow-balance information can be obtained with spatially localized samples at as few as four poloidal locations. Real-geometry simulations have been undertaken, using the nonlinear ?f-PIC gyrokinetic code SUMMIT/PG3EQ_NC, of the DIII-D 'Cyclone' shot #81499 and of shot #118561, which had broad-wavenumber-range density fluctuation measurements. Real geometry is found to have a significant effect on the transport rates, even though the effect on the linear growth rates is often modest.

Dimits, A. M.; Nevins, W. M.; Shumaker, D. E.; Hammett, G. W.; Dannert, T.; Jenko, F.; Pueschel, M. J.; Dorland, W.; Cowley, S. C.; Leboeuf, J. N.; Rhodes, T. L.; Candy, J.; Estrada-Mila, C.

2007-08-01

118

LVPD Plasma for Studies on ETG Turbulence  

NASA Astrophysics Data System (ADS)

Role of electron temperature gradient (ETG) in plasma turbulence in tokamaks has been recognized in various experimental and theoretical investigations on plasma transport. However, investigations of ETG turbulence in tokamak devices have been based upon indirect inferences drawn from experimental database. Nor has it been experimentally investigated in basic plasma devices as it is very difficult to produce electron temperature gradient. In this paper, we show that this can be secured by making use of a magnetic electron energy filter. The plasma in Large Volume Plasma Device is characterized by plasma density, ne0 ˜ 3x10^11 cm-3 and Te0 ˜ 3 eV. In this device, we have provided a magnetic filter consisting of 155- turns rectangular coil of 4 cm width and varying length of ˜ 192 to15 cm from centre to the edge. The field at the centre of the coil is <= 150 G, leaving a residual magnetic field of <= 1 G in the region of experimental investigations. Our results show that ?Te in the flat electron density region can be secured by providing radial inhomogenity in filter magnetic field. Scale length of gradient can be varied from 200 cm to 40 cm in a controlled manner. This has allowed us to undertake detailed investigations on ETG turbulence.

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

2010-11-01

119

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

120

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

121

Correlation between Bilirubin Glucuronidation and Estradiol-3-Gluronidation in the Presence of Model UDP-Glucuronosyltransferase 1A1 Substrates/Inhibitors  

PubMed Central

Inhibition of UDP-glucuronosyltransferase (UGT) 1A1-catalyzed bilirubin glucuronidation by drug compounds may potentially be of clinical concern. However, in drug discovery and development settings, bilirubin is less than an ideal in vitro probe for assessing the potential of a chemical entity to inhibit bilirubin glucuronidation. In part, this is due to the propensity of bilirubin to photodegrade and to the instability of its metabolites. To this end, the utility of estradiol-3-glucuronidation as a surrogate in vitro predictor for interactions with bilirubin was evaluated. The glucuronidation kinetics of bilirubin and estradiol were carefully characterized with recombinant UGT1A1 expressed in human embryonic kidney 293 cells. Consistent with previous reports, estradiol-3-glucuronidation displayed sigmoidal kinetics, whereas bilirubin glucuronidation exhibited typical hyperbolic kinetics. The two compounds also mutually inhibited the metabolism of the other. Sixteen UGT1A1 substrates/inhibitors were evaluated as effectors of each reaction. Fourteen compounds inhibited both bilirubin and estradiol glucuronidation. However, two compounds (ethinylestradiol and daidzein) exhibited mixed effects (concentration-dependent activation and inhibition) on estradiol-3-glucuronidation, whereas bilirubin glucuronidation was inhibited by both compounds. In addition, 7-ethyl-10-hydroxycamptothecin, a substrate of UGT1A1 (reported Km = 24 ?M) seemed to be a weak inhibitor of bilirubin glucuronidation (IC50 = 356.4 ?M) but a partial inhibitor of estradiol-3-glucuronidation. The IC50 values of the inhibitors against estradiol-3-glucuronidation were strongly correlated with IC50 values against bilirubin glucuronidation, resulting in an R2 value of 0.9604 (activator excluded) or 0.8287 (activator included). Thus, estradiol-3-glucuronidation can serve as a good surrogate for predicting inhibition of bilirubin glucuronidation with the caveat that occasionally compounds may demonstrate activation of estradiol-3-glucuronidation.

Zhou, Jin; Tracy, Timothy S.

2011-01-01

122

X-ray properties of optically selected ETGs (Danielson+, 2012)  

NASA Astrophysics Data System (ADS)

We study the X-ray properties of 393 optically selected early-type galaxies (ETGs) over the redshift range of z~~0.0-1.2 in the Chandra Deep Fields (CDFs). To measure the average X-ray properties of the ETG population, we use X-ray stacking analyses with a subset of 158 passive ETGs (148 of which were individually undetected in X-ray). This ETG subset was constructed to span the redshift ranges of z=0.1-1.2 in the ~~4Ms CDF-South and ~~2Ms CDF-North and z=0.1-0.6 in the ~~250ks Extended-CDF-South where the contribution from individually undetected active galactic nuclei (AGN) is expected to be negligible in our stacking. (2 data files).

Danielson, A. L. R.; Lehmer, B. D.; Alexander, D. M.; Brandt, W. N.; Luo, B.; Miller, N.; Xue, Y. Q.; Stott, J. P.

2012-11-01

123

The radioimmunoassay of steroid glucuronides. The oestrogen C-3 glucuronides as haptens.  

PubMed Central

Antisera were prepared against three related oestrogen ring-A glucuronides, oestrone 3-glucuronide, oestradiol 3-glucuronide and oestriol 3-glucuronide. The corresponding 6,7-3H-labelled conjugates were synthesized as radioligands and the cross-reactions of the antisera against ring-A oestrogen glucuronides and other steroid conjugates were examined. The specificity of the antiserum against oestriol 3-glucuronide was compared with that raised against oestriol 16alpha-glucuronide, and the measurement of the former conjugate in late-pregnancy urine is discussed.

Samarajeewa, P; Kellie, A E

1975-01-01

124

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

125

Direct determination of estriol 3- and 16-glucuronides in pregnancy urine by column-switching high-performance liquid chromatography with fluorescence detection  

Microsoft Academic Search

An HPLC method for the direct and simultaneous determination of estriol 3- and 16-glucuronides in pregnancy urine is described. The method is based on direct derivatization of the glucuronic acid moiety in estriol glucuronides in urine with 6,7-dimethoxy-1-methyl-2(1H)-quinoxalinone-3-propionylcarboxylic acid hydrazide. The derivatization reaction proceeds in aqueous solution (or urine sample) in the presence of pyridine and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide at 37°C.

Tetsuharu Iwata; Tsuyoshi Hirose; Masatoshi Yamaguchi

1997-01-01

126

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

127

Collisional Damping of ETG-Mode-Driven Zonal Flows  

Microsoft Academic Search

We study collisional damping of electron zonal flows in toroidal electron temperature gradient (ETG) turbulence due to the friction between trapped and untrapped electrons. With the assumption of adiabatic ions, the collisional damping is shown to occur on fast time scales ˜0.24?1\\/2taue. The comparison with the growth rate of electron zonal flows indicates that the shearing by electron zonal flows

Eun-Jin Kim; C. Holland; P. H. Diamond

2003-01-01

128

Advanced Fluctuation Diagnostics for ITG and ETG modes on NSTX*  

NASA Astrophysics Data System (ADS)

Recent progress in Microwave Imaging Reflectometry clearly demonstrated that the conventional reflectometry operating in the diffraction limit, which has been widely used for ITG modes (k_bot ?i ˜ 0.2) in toroidal devices, has severe constraints in real applications. Imaging Reflectometry for long wavelength ITG modes can remedy these shortcoming on NSTX although the high magnetic shear and low magnetic field of NSTX may add more complexity to the system compared to that of the conventional tokamak (e.g. TEXTOR). The electron thermal transport has been cited in recent years as one of the major scientific transport challenges in fusion research. Recent numerical simulations have shown that extremely small amplitude ( ˜0.1 %) and short-scale (k_bot ?e ˜ 0.2) turbulent fluctuations driven by the ETG mode could significantly affect the transport of electrons in NSTX. The high magnetic shear in the ST provides an excellent spatial resolution for coherent scattering which is ideal for the search for ETG modes. On NSTX, advance diagnostic systems such as MIR system and high-resolution scattering system with the excellent spatial and k resolution for both ITG and ETG turbulence studies, are essential for understanding the transport physics of the Spherical Torus.

Park, H.; Hahm, T. S.; Mazzucato, E.; Munsat, T.; Synakowski, E.; Domier Luhmann, C. W., Jr.; Idehara, T.

2002-11-01

129

Dimensionless parameters, scaling laws, and the implications for ETG  

SciTech Connect

ETG will be useful in resolving several physical issues relevant to Spherical Tokamak Reactor concepts. First, it will provide a test of whether transport is Bohm or gyro-Bohm in nature. The second point is that ETG will operate in a completely different range of {rho}* space from other high performance machines, opening up a previously inaccessible region of parameter space. ETG is also a (very) high-{beta} machine. It would be the only device that would have all of its parameters except {rho}* similar to those of a Spherical tokamak Reactor. If it turns out that the transport scales definitively as either Bohm or gyro-Bohm, then extrapolation to reactor conditions with significantly lower values of {rho}* would become more credible. It is also shown that in general one cannot obtain a power law relation in the dimensionless variables for the confinement tim from a power law fit to the engineering variables. It is shown, however, that if T{sub i}/T{sub e} and n{sub i}/n{sub e} are constant or if a modified definition of certain dimensionless variables is adopted, then such a power law conversion is possible.

Castle, G.G.

1995-04-20

130

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

2011-04-01

131

Investigation of ETG mode-scale component of tokamak plasma turbulence by correlative enhanced scattering diagnostics  

Microsoft Academic Search

The new diagnostic technique for investigation of ETG mode-scale tokamak turbulence–correlative enhanced scattering is developed at the FT-2 tokamak. Fine scale drift wave modes possessing unusually high frequency are observed using this technique in the ohmic discharge under conditions when the ETG mode should be unstable.

E Z Gusakov; A D Gurchenko; A B Altukhov; A Yu Stepanov; L A Esipov; M Yu Kantor; D V Kouprienko

2006-01-01

132

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

Microsoft Academic Search

The unique case of a 50-year-old known alcoholic whose corpse was exhumed 27 years after death is reported. The man apparently\\u000a committed suicide by hanging, but many years later the case was questioned and homicide—linked to a long-lasting serial killer\\u000a case—was suspected. Thus, the corpse was exhumed, and at the autopsy it was found to be naturally mummified. This fact permitted

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

2008-01-01

133

Comparing the glucuronidation capacity of the feline liver with substrate-specific glucuronidation in dogs.  

PubMed

This study aimed to assess the overall glucuronidation capacity of cats, using prototypic substrates identified for human UDP-glucuronosyltransferases (UGTs). To this end, Michaelis-Menten kinetics were established for the substrates using feline hepatic microsomal fractions, and results were compared with similar experiments carried out with dog liver microsomes. Cats are known for their low capacity of glucuronide formation, and UGT1A6 was found to be a pseudogene. However, functional studies with typical substrates were not performed and knowledge of the enzymology and genetics of other glucuronidation enzymes in felidae is lacking. The results of this study showed extremely low formation of naphthol-1-glucuronide (1.7 ± 0.4 nmol/mg protein/min), estradiol-17-glucuronide (<0.7 nmol/mg protein/min), and morphine-3-glucuronide (0.2 ± 0.03 nmol/mg protein/min), suggesting a lack of functional UGT1A6 and UGT2B7 homologues in the cat's liver. Dog liver microsomes were producing these glucuronides in much higher amounts. Glucuronide capacity was present for the substrates 17?-estradiol (estradiol-3-glucuronide, 2.9 ± 0.2 nmol/mg protein/min) and 4-methylumbelliferone (31.3 ± 3.3 nmol/mg protein/min), assuming that cats have functional homologue enzymes to at least the human UGT1A1 and probably other UGT1A isozymes. This implies that for new drugs, glucuronidation capacity has to be investigated on a substance-to-substance base. Knowledge of the glucuronidation rate of a drug provides the basis for pharmacokinetic modeling and as a result proper dosage regimens can be established to avoid undesirable drug toxicity in cats. PMID:23888985

van Beusekom, C D; Fink-Gremmels, J; Schrickx, J A

2014-02-01

134

Statistical Characteristics from ETG/ITG Gyrofluid Simulations  

NASA Astrophysics Data System (ADS)

In order to find rules to identify turbulent dynamics in tokamak plasmas, we studied the statistical characteristics from gyrofluid simulation for electron/ion temperature gradient (ETG/ITG) turbulence in sheared slab configuration. The statistical characteristics such as fractal dimension, Lyapunov number, probability density function (PDF) are investigated in details for various turbulent structures dominated by intermittency, zonal flow, and nonlinearly excited tertiary waves. High dimensionality (d ˜8-10) and prominent exponential PDF tails are observed in turbulent plasmas, which exhibit an intermittent transport dynamics. The PDF tails are found to shows a prominent similarity insensitive to the plasma parameters such as temperature gradient and magnetic shear. On the other hand, in plasmas dominated by zonal flows and tertiary waves (Kelvin-Helmholtz), which is established in weak magnetic shear regime [1], a significant dimensionality lowering (up to d ˜3) is observed accompanied by disappearance of the exponential tails. The relation among different statistical values will be discussed. [1] J.Q.Li and Y. Kishimoto, Phys. Plasmas 11, 1493 (2004).

Matsumoto, Taro; Kishimoto, Yasuaki; Li, Jiquan

2004-11-01

135

In silico prediction of acyl glucuronide reactivity.  

PubMed

Drugs and drug candidates containing a carboxylic acid moiety, including many widely used non-steroidal anti-inflammatory drugs (NSAIDs) are often metabolized to form acyl glucuronides (AGs). NSAIDs such as Ibuprofen are amongst the most widely used drugs on the market, whereas similar carboxylic acid drugs such as Suprofen have been withdrawn due to adverse events. Although the link between these AG metabolites and toxicity is not proven, there is circumstantial literature evidence to suggest that more reactive acyl glucuronides may, in some cases, present a greater risk of exhibiting toxic effects. We wished therefore to rank the reactivity of potential new carboxylate-containing drug candidates, and performed kinetic studies on synthetic acyl glucuronides to benchmark our key compounds. Driven by the desire to quickly rank the reactivity of compounds without the need for lengthy synthesis of the acyl glucuronide, a correlation was established between the degradation half-life of the acyl glucuronide and the half life for the hydrolysis of the more readily available methyl ester derivative. This finding enabled a considerable broadening of chemical property space to be investigated. The need for kinetic measurements was subsequently eliminated altogether by correlating the methyl ester hydrolysis half-life with the predicted (13)C NMR chemical shift of the carbonyl carbon together with readily available steric descriptors in a PLS model. This completely in silico prediction of acyl glucuronide reactivity is applicable within the earliest stages of drug design with low cost and acceptable accuracy to guide intelligent molecular design. This reactivity data will be useful alongside the more complex additional pharmacokinetic exposure and distribution data that is generated later in the drug discovery process for assessing the overall toxicological risk of acidic drugs. PMID:22042375

Potter, Tim; Lewis, Richard; Luker, Tim; Bonnert, Roger; Bernstein, Michael A; Birkinshaw, Timothy N; Thom, Stephen; Wenlock, Mark; Paine, Stuart

2011-11-01

136

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

137

ETG turbulence simulation of tokamak edge plasmas via 3+1 gyrofluid code  

NASA Astrophysics Data System (ADS)

To study ETG driven turbulence at H-mode pedestal, which is important for the magnetic reconnection of ELM dynamics via ETG-MHD interaction, a 3+1 gyrofluid code is developed under BOUT++ framework. Four evolving quantities are density, parallel velocity, parallel pressure and perpendicular pressure for electron and adiabatic ion is used. Gyro-average is done by utilizing Pad'e approximation and parallel Landau closure for Landau damping is implemented by using a newly developed non-Fourier method. By calculating the ETG mode growth rate and real frequency for the ETG cyclone equilibrium, our code is benchmarked with gyrokinetic codes. We also calculated the electron heat transport level at turbulence saturation phase for both cyclone case and H-mode pedestal. Because the pedestal width is typically ten times larger than ETG simulation domain, the three different region of pedestal, i.e. pedestal top, peak gradient region and pedestal bottom, are simulated separately. The dramatic difference on magnetic shear and temperature length scale of these three regions lead to different ETG linear and nonlinear behaviors.

Xi, P. W.; Xu, X. Q.; Dimits, A.; Umansky, M.; Joseph, I.; Kim, S. S.

2012-10-01

138

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

139

A highly toxic morphine-3-glucuronide derivative.  

PubMed

By the coupling of octylamine to the uronic acid function of morphine-3-glucuronide (M3G) a new glycoconjugate (morphine-3-octylglucuronamide, M3GOAM) was prepared. When assayed in both rats and mice up to ng/kg (i.p.) doses none of the animals survived. The aliphatic octyl chain may be the lethal factor since a closely related derivative (M3GNH2), was not toxic and showed similar opioid antagonist properties than naloxone. PMID:15012991

Salvatella, Mariona; Arsequell, Gemma; Valencia, Gregorio; Rodríguez, Raquel E

2004-02-23

140

Enzymic synthesis of two glucuronides of the hydroxyisoxazole GABA-agonist, THIP, and the in vivo glucuronidation of THIP in rat.  

PubMed

1. A method for preparative enzymic synthesis of two glucuronides of THIP (3-hydroxy-4,5,6,7-tetrahydro-isoxazolo[5,4-c]pyridine) is described. 2. Using FAB mass spectrometry, u.v. and 1H- and 13C-n.m.r. spectroscopy, the two glucuronides were identified as N- and O-glucuronides respectively. 3. An h.p.l.c. method for determination of THIP and the two intact glucuronides in urine has been developed. 4. The glucuronidation pattern of THIP in rats has been examined; THIP was excreted as a THIP-O-glucuronide but not as a THIP-N-glucuronide. PMID:2618090

Andersen, J V; Dalgaard, L; Hansen, S H

1989-12-01

141

On the Nature of ETG Turbulence and Cross-Scale Coupling  

Microsoft Academic Search

Microturbulence in tokamaks and stellarators is studied via gyrokinetic simulation and semi-analytical theory. The focus is on electron temperature gradient (ETG) turbulence and its interactions with fluctuations at longer wavelengths. In this context, special attention is paid to the physics of edge transport barriers.

JENKO Frank

142

Gyrokinetic Studies of Turbulence Reduction with Reverse Shear ETG Transport Barriers or Lithium Walls  

NASA Astrophysics Data System (ADS)

The National Spherical Torus Experiment (NSTX) can achieve high electron confinement regimes that are super-critically unstable to the electron temperature gradient (ETG) instability. These electron internal transport barriers (e-ITBs) occur when the magnetic shear becomes strongly negative. Using the gyrokinetic code GYRO, the first nonlinear ETG simulations of NSTX e-ITB plasmas demonstrate reduced turbulence consistent with this observation. This is qualitatively consistent with a secondary instability picture of reduced ETG turbulence at negative shear (Jenko and Dorland PRL 2002). Local simulations identify a strongly upshifted nonlinear critical gradient for thermal transport that depends on magnetic shear. Global simulations show that ETG-driven turbulence outside of the barrier is large enough to be experimentally relevant, but cannot propagate very far into the barrier. We also use GYRO to study turbulence in regimes that might be expected in the Lithium Torus eXperiment (LTX). While lithium has experimentally been shown to raise the edge temperature and improve performance, there can still be some turbulence from density-gradient-driven trapped electron modes, and a temperature pinch is found in some cases. (Supported by DOE.)

Hammett, G. W.; Peterson, J. L.; Granstedt, E. M.; Bell, R.; Guttenfelder, W.; Kaye, S.; Leblanc, B.; Mikkelsen, D. R.; Smith, D. R.; Yuh, H. Y.; Candy, J.

2012-03-01

143

A Preliminary Basic Experiment on the Production and Identification of Toroidal ETG Modes  

NASA Astrophysics Data System (ADS)

Production and identification of the slab branch of the Electron Temperature Gradient (ETG) mode and the measurement of the consequent electron thermal conductivity have been successfully made in a basic experiment in Columbia Linear Machine (CLM) [1,2]. A preliminary experiment on the transition of the slab mode to the toroidal (curvature) branch of ETG mode in CLM is reported. CLM was operated in the mirror configuration with cell length (50cm-100cm) and mirror ratio (1-2.2). The radius of curvature is Rc˜1.3m and the critical ratio for the transition to toroidal mode has been achieved, k| / 2 ?nk< 0.1 [3]. We first excite the slab ETG mode [1] and gradually increase the magnetic curvature drive by increasing the magnetic mirror ratio, and observe an increase of the ETG mode amplitude up to 2 times and a small change in mode frequency. Alternatively, we can shorten the mirror cell length via moving the mirror coil to increase the bounce average curvature drive and the mode amplitude. [4pt] [1] X.Wei, V.Sokolov, and A.K. Sen, Phys. Plasmas 17, 042108 (2010).[0pt] [2] V.Sokolov, and A.K. Sen, Phys. Rev. Lett. 107, 155001 (2011).[0pt] [3] J.Y.Kim and W.Horton, Phys.Fluids B 3, 1167 (1991).

Sokolov, Vladimir; Balbaky, Abed; Sen, Amiya K.

2012-10-01

144

Detection of pentachlorophenol and its glucuronide and sulfate conjugates in fish bile and exposure water  

SciTech Connect

The glucuronide and sulfate conjugates of pentachlorophenol (PCP) that were present in the bile and exposure water of goldfish (Carassius auratus) were used to develop methodology to quantify PCP and its metabolites. Reverse phase HPLC with radioactivity detection separated PCP and its metabolites, and was used to verify a method of quantification that used differential extraction and scintillation counting. Extractions of aqueous phase at pH 2 or 8, with butanol, ethyl acetate, or ether indicated that ether at pH 8 best separated PCP from its metabolites. The sulfate conjugate of PCP was the major metabolite produced when goldfish were exposed to 125 micrograms UC-PCP/l. It was present primarily in the exposure water, but also appeared in the bile.

Stehly, G.R.; Hayton, W.L.

1988-08-01

145

Observation of the ETG mode component of tokamak plasma turbulence by the UHR backscattering diagnostics  

Microsoft Academic Search

A fine scale drift wave mode possessing unusually high frequency 2-3 MHz and radial wave number is observed using the correlative upper hybrid resonance backscattering technique at the FT-2 tokamak under conditions when the ETG mode should be unstable. The radial wave number spectrum of turbulence is measured and shown to be maximal at values 120-170 cm-1 corresponding to the

A. D. Gurchenko; E. Z. Gusakov; A. B. Altukhov; A. Yu. Stepanov; L. A. Esipov; M. Yu. Kantor; D. V. Kouprienko; V. V. Dyachenko; S. I. Lashkul

2007-01-01

146

ETG Modeling of a TCV Multi-Phase H-Mode Shot  

NASA Astrophysics Data System (ADS)

TCV is well suited for electron transport studies due to its well developed ECRH system. Ion heating is achieved by thermal equilibration at high density in combination with strong third harmonic X-mode (X3) ECRH heating. In TCV shot 29892, X3 heating was applied to an ohmic ELMy H-mode, either at full or modulated power. This shot covers four stationary H-mode phases, one ohmic followed by three ELMy or ELM-free X3 heated. The final two are akin to improved H-modes. Previous analysis with the GLF model implied the discharge to be ITG dominated, in accordance with a preliminary Weiland stability analysis. As the applied heating only affects the electrons it is important to analyze this discharge regarding ETG and/or TEM modes. The ETG turbulence calculated with the IFS-ETG model will be presented. This model has already successfully calculated electron transport in dominantly electron-heated NSTX and Tore Supra.

Asp, Elina; Kim, Juhyung; Horton, Wendell; Porte, Laurie; Alberti, Stefano; Fable, Emiliano; Martin, Yves; Sauter, Olivier; Turri, Gianpaolo

2007-11-01

147

The structure of the glucuronide of sulphadimethoxine formed in man  

PubMed Central

1. The major metabolite of 2,4-dimethoxy-6-sulphanilamidopyrimidine (sulphadimethoxine) in urine in man is a non-reducing glucuronide, which has been isolated and characterized as its S-benzylthiouronium salt. 2. The same compound was made synthetically by standard methods from sodium sulphadimethoxine and methyl 2,3,4-tri-O-acetyl-1-bromoglucuronate. 3. On hydrolysis with acid, the glucuronide yielded sulphanilic acid, glucuronic acid and barbituric acid, and with ?-glucuronidase it slowly yielded sulphadimethoxine and glucuronic acid. 4. Evidence based on infrared spectra and other data showed that the urinary and synthetic glucuronide was 1-deoxy-1-[N1?-(2?,4?-dimethoxypyrimidin-6? -yl)sulphanilamido-?-d-glucosid]uronic acid or sulphadimethoxine N1-glucuronide. 5. N1-Methyl- and Nring-methyl derivatives of sulphadimethoxine and 4-methoxy-6-sulphanilamidopyrimidine were prepared and their infrared and ultraviolet spectra determined for comparison.

Bridges, J. W.; Kibby, M. R.; Williams, R. T.

1965-01-01

148

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

149

Conjugation position of quercetin glucuronides and effect on biological activity  

Microsoft Academic Search

Quercetin glycosides are common dietary antioxidants. In general, however, potential biological effects of the circulating plasma metabolites (e.g., glucuronide conjugates) have not been measured. We have determined the rate of glucuronidation of quercetin at each position on the polyphenol ring by human liver cell-free extracts containing UDP-glucuronosyltransferases. The apparent affinity of UDP-glucuronosyltransferase followed the order 4?- > 3?- > 7-

Andrea J Day; Yongping Bao; Michael R. A Morgan; Gary Williamson

2000-01-01

150

Demethylzeylasteral exhibits dose-dependent inhibitory behaviour towards estradiol glucuronidation.  

PubMed

The disturbance of estradiol level might induce the occurence of some diseases, including cancer. Estradiol is mainly metabolized through the conjugation reactions, including the sulfation and glucuronidation reactions. The present study tried to evaluate the inhibition of estradiol glucuronidation by the major ingredients of Tripterygium wilfordii Hook F. demethylzeylasteral. Selective ion monitoring at negative ion mode ([M + H](-) = 447) was employed to monitor the two glucuronides of estradiol. The reaction rate was determined through comparison of peak area of these two glucuronides. Lineweaver-Burk plot and Dixon plot were utilized to determine the inhibition kinetic type, and the inhibition kinetic parameters (K i ) were calculated using the second plot. Competitive inhibition of demethylzeylasteral towards the formation of two glucuronides of estradiol was demonstrated, and the K i values were calculated to be 453.3 and 110.9 ?M, respectively. All these results will remind us the risk of elevated serum concentrations of estradiol due to the inhibition of estradiol glucuronidation by demethylzeylasteral. PMID:23807732

Liu, Su-Lin; Zhang, Shu-Yao; Wang, Miao-Jun; Jiang, Hong; Yang, Yu-Xian; Chen, Lei

2014-06-01

151

Synthesis, hydrolysis and stability of psilocin glucuronide.  

PubMed

A two-step synthesis of psilocin glucuronide (PCG), the main metabolite of psilocin, with methyl 2,3,4-tri-O-isobutyryl-1-O-trichloroacetimidoyl-?-d-glucopyranuronate is reported. With the synthesized PCG, hydrolysis conditions in serum and urine were optimized. Escherichia coli proved to be a better enzyme source for ?-glucuronidase than Helix pomatia. It was essential to add ascorbic acid to serum samples to protect psilocin during incubation. Furthermore the stability of PCG and psilocin was compared as stability data are the basis for forensic interpretation of measurements. PCG showed a greater long-term stability after six months in deep frozen serum and urine samples than psilocin. The short-term stability of PCG for one week in whole blood at room temperature and in deep frozen samples was also better than that of psilocin. Therefore, PCG can be considered to be more stable than the labile psilocin and should always be included if psilocin is analyzed in samples. PMID:24513688

Martin, Rafaela; Schürenkamp, Jennifer; Pfeiffer, Heidi; Lehr, Matthias; Köhler, Helga

2014-04-01

152

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

153

Hepatocyte cotransport of taurocholate and bilirubin glucuronides: Role of microtubules  

SciTech Connect

Modulation of bile pigment excretion by bile salts has been attributed to modification of canalicular membrane transport or a physical interaction in bile. Based on the observation that a microtubule-dependent pathway is involved in the hepatocellular transport of bile salts, the authors investigated the possibility that bilirubin glucuronides are associated with bile salts during intracellular transport. Experiments were conducted in intact rats (basal) or after overnight biliary diversion and intravenous reinfusion of taurocholate (depleted/reinfused). All rats were pretreated with intravenous low-dose colchicine or its inactive isomer lumicolchicine. Biliary excretion of radiolabeled bilirubin glucuronides derived from tracer ({sup 14}C)bilirubin-({sup 3}H)bilirubin monoglucuronide (coinjected iv) was unchanged in basal rats but was consistently delayed in depleted/reinfused rats. This was accompanied by a significant shift toward bilirubin diglucuronide formation from both substrates. In basal Gunn rats, with deficient bilirubin glucuronidation, biliary excretion of intravenous ({sup 14}C)bilirubin monoglucuronide-({sup 3}H)bilirubin diglucuronide was unaffected by colchicine but was retarded in depleted/reinfused Gunn rats. Colchicine had no effect on the rate of bilirubin glucuronidation in vitro in rat liver microsomes. They conclude that a portion of the bilirubin glucuronides generated endogenously in hepatocytes or taken up directly from plasma may be cotransported with bile salts to the bile canalicular membrane via a microtubule-dependent mechanism.

Crawford, J.M.; Gollan, J.L. (Harvard Medical School, Boston, MA (USA))

1988-07-01

154

In Vitro Glucuronidation of Ochratoxin A by Rat Liver Microsomes  

PubMed Central

Ochratoxin A (OTA), one of the most toxic mycotoxins, can contaminate a wide range of food and feedstuff. To date, the data on its conjugates via glucuronidation request clarification and consolidation. In the present study, the combined approaches of ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), UHPLC-Orbitrap-high resolution mass spectrometry (HRMS) and liquid chromatography-multiple stage mass spectrometry (LC-MSn) were utilized to investigate the metabolic profile of OTA in rat liver microsomes. Three conjugated products of OTA corresponding to amino-, phenol- and acyl-glucuronides were identified, and the related structures were confirmed by hydrolysis with ?-glucuronidase. Moreover, OTA methyl ester, OT? and OT?-glucuronide were also found in the reaction solution. Based on these results, an in vitro metabolic pathway of OTA has been proposed for the first time.

Han, Zheng; Tangni, Emmanuel K.; Diana Di Mavungu, Jose; Vanhaecke, Lynn; De Saeger, Sarah; Wu, Aibo; Callebaut, Alfons

2013-01-01

155

In vitro glucuronidation of ochratoxin a by rat liver microsomes.  

PubMed

Ochratoxin A (OTA), one of the most toxic mycotoxins, can contaminate a wide range of food and feedstuff. To date, the data on its conjugates via glucuronidation request clarification and consolidation. In the present study, the combined approaches of ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), UHPLC-Orbitrap-high resolution mass spectrometry (HRMS) and liquid chromatography-multiple stage mass spectrometry (LC-MS(n)) were utilized to investigate the metabolic profile of OTA in rat liver microsomes. Three conjugated products of OTA corresponding to amino-, phenol- and acyl-glucuronides were identified, and the related structures were confirmed by hydrolysis with ?-glucuronidase. Moreover, OTA methyl ester, OT? and OT?-glucuronide were also found in the reaction solution. Based on these results, an in vitro metabolic pathway of OTA has been proposed for the first time. PMID:24351721

Han, Zheng; Tangni, Emmanuel K; Di Mavungu, José Diana; Vanhaecke, Lynn; De Saeger, Sarah; Wu, Aibo; Callebaut, Alfons

2013-12-01

156

Microvascular protective activity of flavonoid glucuronides fraction from Tulipa gesneriana.  

PubMed

A mixture of flavonoid glucuronides, consisting of 7-O-glucuronides of kaempferol and quercetin 3-O-rutinosides, 3-O-gentiobiosides and 3-O-glucosides, was isolated from the perianths of Tulipa gesneriana L. var. 'Paradae'. It showed protective activity against the increased (both chloroform and histamine) skin vascular permeability in rabbits. The protective effect, measured as the reduction in leakage of Evans blue, was 59.8% after peritoneal treatment at a dose of 25 mg/kg, while that of troxerutin was 45.5%. PMID:10190195

Budzianowski, J; Korzeniowska, K; Chmara, E; Mrozikiewicz, A

1999-03-01

157

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

158

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

159

The MCM-Binding Protein ETG1 Aids Sister Chromatid Cohesion Required for Postreplicative Homologous Recombination Repair  

Microsoft Academic Search

The DNA replication process represents a source of DNA stress that causes potentially spontaneous genome damage. This effect might be strengthened by mutations in crucial replication factors, requiring the activation of DNA damage checkpoints to enable DNA repair before anaphase onset. Here, we demonstrate that depletion of the evolutionarily conserved minichromosome maintenance helicase-binding protein ETG1 of Arabidopsis thaliana resulted in

Naoki Takahashi; Mauricio Quimbaya; Veit Schubert; Tim Lammens; Klaas Vandepoele; Ingo Schubert; Minami Matsui; Dirk Inzé; Geert Berx; Lieven De Veylder

2010-01-01

160

Partial characterization of biliary metabolites of pulegone by tandem mass spectrometry. Detection of glucuronide, glutathione, and glutathionyl glucuronide conjugates.  

PubMed

The hepatotoxic monoterpene pulegone is a major constituent of the herbal abortifacient pennyroyal oil. An approximately equimolar mixture of 2H3- and 14C-labeled pulegone was administered to rats to study its phase II metabolism. Radioactive conjugates that were excreted into the bile were isolated by selective derivatization and HPLC separation, and subsequently characterized from the daughter ion mass spectra of protio- and deutero-analogs of each metabolite. The biliary metabolites characterized were glucuronide and glutathione (GSH) conjugates, accounting for approximately 3% of the radioactivity excreted in bile. The glucuronides, which were 2-fold more abundant than GSH conjugates, were mainly of hydroxylated pulegone and hydroxylated, reduced pulegone. The three GSH conjugates contained xenobiotic moieties that varied in their oxidation state; one of these was tentatively identified as the GSH conjugate of the proximate oxygenated metabolite, menthofuran. The two other GSH conjugates apparently underwent subsequent glucuronidation since novel glutathionyl glucuronide conjugates were identified that contained nonhydroxylated xenobiotic moieties. The results indicate that pulegone is bioactivated via at least three distinct pathways, each marked by a different GSH conjugate. Characterization of these conjugates represents a first step in the identification of the reactive metabolites from which they are derived. PMID:1686249

Thomassen, D; Pearson, P G; Slattery, J T; Nelson, S D

1991-01-01

161

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

162

Omega-3-acid Ethyl Esters  

MedlinePLUS

Omega-3-acid ethyl esters are used together with lifestyle changes (diet, weight-loss, exercise) to reduce the amount ... a fat-like substance) in your blood. Omega-3-acid ethyl esters are in a class of ...

163

Morphine glucuronidation in human fetal and adult liver  

Microsoft Academic Search

Summary  The glucuronyltransferase activity towards morphine was measured in microsomes isolated from liver specimens obtained from\\u000a human fetuses and cancer patients. All the fetal livers investigated had measurable UDP-glucuronyltransferase activity towards\\u000a morphine. There was no correlation between the gestational age (15 to 27 weeks) and the glucuronidation rate. The mean value\\u000a of the enzymatic activities was higher in fetal livers obtained

G. M. Pacifici; J. Säwe; L. Kager; A. Rane

1982-01-01

164

Glucuronidation of psilocin and 4-hydroxyindole by the human UDP-glucuronosyltransferases.  

PubMed

We have examined the glucuronidation of psilocin, a hallucinogenic indole alkaloid, by the 19 recombinant human UDP-glucuronosyltransferases (UGTs) of subfamilies 1A, 2A, and 2B. The glucuronidation of 4-hydroxyindole, a related indole that lacks the N,N-dimethylaminoethyl side chain, was studied as well. UGT1A10 exhibited the highest psilocin glucuronidation activity, whereas the activities of UGTs 1A9, 1A8, 1A7, and 1A6 were significantly lower. On the other hand, UGT1A6 was by far the most active enzyme mediating 4-hydroxyindole glucuronidation, whereas the activities of UGTs 1A7-1A10 toward 4-hydroxyindole resembled their respective psilocin glucuronidation rates. Psilocin glucuronidation by UGT1A10 followed Michaelis-Menten kinetics in which psilocin is a low-affinity high-turnover substrate (K(m) = 3.8 mM; V(max) = 2.5 nmol/min/mg). The kinetics of psilocin glucuronidation by UGT1A9 was more complex and may be best described by biphasic kinetics with both intermediate (K(m1) = 1.0 mM) and very low affinity components. The glucuronidation of 4-hydroxyindole by UGT1A6 exhibited higher affinity (K(m) = 178 microM) and strong substrate inhibition. Experiments with human liver and intestinal microsomes (HLM and HIM, respectively) revealed similar psilocin glucuronidation activity in both samples, but a much higher 4-hydroxyindole glucuronidation rate was found in HLM versus HIM. The expression levels of UGTs 1A6-1A10 in different tissues were studied by quantitative real-time-PCR, and the results, together with the activity assays findings, suggest that whereas psilocin may be subjected to extensive glucuronidation by UGT1A10 in the small intestine, UGT1A9 is likely the main contributor to its glucuronidation once it has been absorbed into the circulation. PMID:20007669

Manevski, Nenad; Kurkela, Mika; Höglund, Camilla; Mauriala, Timo; Court, Michael H; Yli-Kauhaluoma, Jari; Finel, Moshe

2010-03-01

165

Characterization of Rat and Human UDP-Glucuronosyltransferases Responsible for the in Vitro Glucuronidation of Diclofenac  

Microsoft Academic Search

In the current study, the identification of the rat and human UDP-glucuronosyltransferase (UGT) isoforms responsible for the glucuronidation of diclofenac was determined. Recombinant hu- man UGT1A9 catalyzed the glucuronidation of diclofenac at a moderate rate of 166-pmol\\/min\\/mg protein, while UGT1A6 and 2B15 catalyzed the glucuronidation of diclofenac at low rates (<20-pmol\\/min\\/mg protein). Conversely, human UGT2B7 dis- played a high rate

C. King; W. Tang; J. Ngui; T. Tephly; M. Braun

2001-01-01

166

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

167

Glucuronidation of nonsteroidal anti-inflammatory drugs: identifying the enzymes responsible in human liver microsomes.  

PubMed

Nonsteroidal anti-inflammatory drugs (NSAIDs), used for the treatment of pain and inflammation, are eliminated primarily through conjugation with polar sugar moieties to form glucuronides. Glucuronidation is catalyzed by the UDP-glucuronosyltransferases (UGT) superfamily. An inverse relationship may exist between glucuronidation activity and NSAID efficacy; however, specific UGTs catalyzing conjugation of the structurally diverse NSAIDs have yet to be identified systematically. Therefore, NSAID glucuronidation activity by 12 individually expressed UGTs was investigated by liquid chromatography-tandem mass spectrometry. The relative rates of NSAID glucuronidation varied among UGT enzymes examined, demonstrating specificity of the individual UGTs toward selected NSAIDs. Kinetic parameters were determined for expressed UGT Supersomes and compared with parameters determined in pooled human liver microsomes (HLMs). Comparison of K(m) values suggested roles for UGTs 1A3 and 2B7 in indene glucuronidation and UGTs 1A9, 2B4, and 2B7 in profen glucuronidation. Inhibitory studies in pooled HLMs support the role of UGTs 1A1, 1A3, 1A9, 2B4, and 2B7 in the glucuronidation of ibuprofen, flurbiprofen, and ketoprofen. Bilirubin did not inhibit indomethacin or diclofenac glucuronidation, suggesting that UGT1A1 was not involved in catalysis. Imipramine did not inhibit glucuronidation of sulindac, sulindac sulfone, indomethacin, or naproxen in pooled HLMs, suggesting that UGT1A3 was not a principal hepatic catalyst. Nevertheless, multiple UGT enzymes, most notably UGTs 1A1, 1A9, 2B4, and 2B7, seem to be involved in the hepatic catalysis of NSAID glucuronidation. PMID:15843492

Kuehl, Gwendolyn E; Lampe, Johanna W; Potter, John D; Bigler, Jeannette

2005-07-01

168

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

169

UDP-glucuronosyltransferases 1A6 and 1A10 catalyze reduced menadione glucuronidation  

SciTech Connect

Menadione (2-methyl-1,4-naphthoquine), also known as vitamin K3, has been widely used as a model compound in the field of oxidative stress-related research. The metabolism of menadione has been studied, and it is known that menadione undergoes a two-electron reduction by NAD(P)H:Quinone oxidoreductase 1 (NQO1) after which the reduced form of menadione (2-methyl-1,4-naphthalenediol, menadiol) is glucuronidated and excreted in urine. To investigate which human UDP-glucuronosyltransferase (UGT) isoforms participate in the glucuronidation of menadiol reduced by NQO1 from menadione, we first constructed heterologously expressed NQO1 in Sf9 cells and tested the menadiol glucuronidating activity of 16 human recombinant UGT isoforms. Of the 16 UGT isoforms, UGTs 1A6, 1A7, 1A8, 1A9, and 1A10 catalyzed menadiol glucuronidation, and, of these, UGTs 1A6 and 1A10 catalyzed menadiol glucuronidation at much higher rates than the other UGTs. Menadiol was regioselectively glucuronidated in the manner of 4-position > 1-position by UGTs 1A7, 1A8, 1A9, and 1A10. In contrast to these UGTs, only UGT1A6 exhibited 1-menadiol-preferential glucuronidating activity. The results suggest possible detoxification pathways for quinones via NQO1 reduction followed by UGT glucuronidation.

Nishiyama, Takahito; Ohnuma, Tomokazu; Inoue, Yuu; Kishi, Takehiko; Ogura, Kenichiro [Department of Drug Metabolism and Molecular Toxicology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji-shi, Tokyo 192-0392 (Japan); Hiratsuka, Akira [Department of Drug Metabolism and Molecular Toxicology, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji-shi, Tokyo 192-0392 (Japan)], E-mail: hiratuka@ps.toyaku.ac.jp

2008-06-27

170

Immobilization of microsomes into alginate beads is a convenient method for producing glucuronides from drugs  

Microsoft Academic Search

The production of glucuronides from drugs by immobilized microsomal uridine diphosphate (UDP)-glucuronosyltransferase has been investigated. Of all the immobilization methods used (covalent binding, adsorption by ionic or hydrophobic interactions), only entrapment of microsomes into alginate beads in the presence of polyethyleneimine was effective in producing high glucuronidation rates, thus leading to the formation of large amounts of metabolites. The performance

Marc Haumont; Jacques Magdalou; Jean-Claude Ziegler; Roselyne Bidault; Jean-Pascal Siest; Gérard Siest

1991-01-01

171

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

2010-04-01

172

49 CFR 173.322 - Ethyl chloride.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 2013-10-01 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...

2013-10-01

173

Steviol glucuronidation and its potential interaction with UDP-glucuronosyltransferase 2B7 substrates.  

PubMed

Hydrolysis of stevioside and rebaudioside A in the gastrointestinal tract after oral intake leads to the formation of steviol, the aglycone, which is absorbed into the circulation. Although in vivo studies have shown that steviol is cleared from the body via glucuronidation, the role of liver vs. intestine in steviol glucuronidation has not been well defined and related UDP-glucuronosyltransferases (UGTs) have not been identified. The present study investigated steviol glucuronidation and obtained kinetic parameters in liver and intestinal microsomes of human and rat, as well as in recombinant human UGT systems. Results suggest that organ specificity exists in the intrinsic clearance of the glucuronidation reaction. Steviol glucuronidation was primarily mediated by UGT2B7 at low concentration and UGT2B7 and UGT1A3 at high concentration. Inhibition studies with selected UGT2B7 substrates indicate that diclofenac displayed a relatively strong inhibition (Ki, 4.2 ?M) against steviol glucuronidation in human liver microsomes. Taken together, the identification of the involvement of UGT2B7 in steviol glucuronidation would provide a mechanistic basis for the evaluation of the interaction between steviol and diclofenac. As metabolic clearance of botanical-derived products can be the objects (victims) of botanical-drug interactions, further studies are needed to investigate the in vivo relevance of such interactions. PMID:24296138

Wang, Meiyu; Lu, Jia; Li, Jiajun; Qi, Huixin; Wang, Yedong; Zhang, Hongjian

2014-02-01

174

Biomarkers for Alcohol Use and Abuse  

Microsoft Academic Search

Clinicians can use several biochemical measurements to objectively assess patients' current or past alcohol use. However, none of these currently available biomarkers—including measures of various liver enzymes and blood volume—are ideal. Several more experimental markers hold promise for measuring acute alcohol consumption and relapse. These include certain alcohol byproducts, such as acetaldehyde, ethyl glucuronide (EtG), and fatty acid ethyl esters

Karen Peterson

175

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. PMID:23592389

Luong, Susan; Fu, Shanlin

2014-03-01

176

Characterization of UDP-glucuronosyltransferases involved in glucuronidation of diethylstilbestrol in human liver and intestine.  

PubMed

Diethylstilbestrol (DES), a synthetic estrogen, is famous for its carcinogenic effects. Human exposure to this compound can occur frequently through dietary ingestion and medical treatment. Glucuronidation has been demonstrated to be a predominant metabolic pathway for DES in human. Therefore, glucuronidation metabolism may have a significant impact on its toxicities, and it is essential to clarify this metabolic pathway. Accordingly, this in vitro study is designed to characterize the UGTs involved in DES glucuronidation and, furthermore, to identify the roles of individual isoforms in the reaction in liver and intestine. Human liver microsomes (HLM) displayed much higher potential for DES glucuronidation than human intestinal microsomes (HIM). The intrinsic clearances in HLM and HIM were demonstrated to be 459 and 14 ?L/min/mg protein, respectively. Assays with recombinant UGTs demonstrated that UGT1A1, -1A3, -1A8, and -2B7 could catalyze DES glucuronidation, among which UGT2B7 showed the highest affinity. Chemical inhibitors of UGT2B7 and UGT1A1/1A3 both displayed similar inhibition against the reaction in UGT2B7 and HLM. In addition, DES glucuronidation in individual HLM exhibited a large individual variability and strongly correlated to UGT2B7 activity. All evidence indicates that UGT2B7 may act as a major enzyme responsible for DES glucuronidation in human liver. For HIM, both UGT2B7 inhibitor and UGT1A1/1A3/1A8 inhibitor exerted moderate inhibition. It is suggested that although UGT2B7 contributes to DES glucuronidation in intestine, other UGTs may contribute equally. In summary, this study characterizes human UGTs involved in DES glucuronidation in human liver and intestine, which may be helpful for further study about DES-related toxicities. PMID:23126256

Zhu, Liangliang; Ge, Guangbo; Liu, Yong; Guo, Zhimou; Peng, Chengcheng; Zhang, Feng; Cao, Yunfeng; Wu, Jingjing; Fang, Zhongze; Liang, Xinmiao; Yang, Ling

2012-12-17

177

In Vitro Stability of Free and Glucuronidated Cannabinoids in Blood and Plasma Following Controlled Smoked Cannabis  

PubMed Central

BACKGROUND Blood and plasma cannabinoid stability is important for test interpretation and is best studied in authentic rather than fortified samples. METHODS Low and high blood and plasma pools were created for each of 10 participants after they smoked a cannabis cigarette. The stabilities of ?9-tetrahydrocannabinol (THC), 11-hydroxy-THC (11-OH-THC), 11-nor-9-carboxy-THC (THCCOOH), cannabidiol (CBD), cannabinol (CBN), THC-glucuronide, and THCCOOH-glucuronide were determined after 1 week at room temperature; 1, 2, 4, 12, and 26 (±2) weeks at 4 °C; and 1, 2, 4, 12, 26 (±2), and 52 (±4) weeks at ?20 °C. Stability was assessed by Friedman test. RESULTS Numbers of THC-glucuronide and CBD-positive blood samples were insufficient to assess stability. In blood, 11-OH-THC and CBN were stable for 1 week at room temperature, whereas THC and THCCOOH-glucuronide decreased and THCCOOH increased. In blood, THC, THCCOOH-glucuronide, THCCOOH, 11-OH-THC, and CBN were stable for 12, 4, 4, 12, and 26 weeks, respectively, at 4 °C and 12, 12, 26, 26, and 52 weeks at ?20 °C. In plasma, THC-glucuronide, THC, CBN, and CBD were stable for 1 week at room temperature, whereas THCCOOH-glucuronide and 11-OH-THC decreased and THCCOOH increased. In plasma, THC-glucuronide, THC, THCCOOH-glucuronide, THCCOOH, 11-OH-THC, CBN, and CBD were stable for 26, 26, 2, 2, 26, 12, and 26 weeks, respectively, at 4 °C and 52, 52, 26, 26, 52, 52, and 52 weeks, respectively, at ?20 °C. CONCLUSIONS Blood and plasma samples should be stored at ?20 °C for no more than 3 and 6 months, respectively, to assure accurate cannabinoid quantitative results.

Karschner, Erin L.; Desrosiers, Nathalie A.; Gorelick, David A.; Huestis, Marilyn A.

2013-01-01

178

Variation in Trans-3?-Hydroxycotinine Glucuronidation Does Not Alter the Nicotine Metabolite Ratio or Nicotine Intake  

PubMed Central

Background CYP2A6 metabolizes nicotine to its primary metabolite cotinine and also mediates the metabolism of cotinine to trans-3?-hydroxycotinine (3HC). The ratio of 3HC to cotinine (the “nicotine metabolite ratio”, NMR) is an in vivo marker for the rate of CYP2A6 mediated nicotine metabolism, and total nicotine clearance, and has been associated with differences in numerous smoking behaviors. The clearance of 3HC, which affects the NMR, occurs via renal excretion and metabolism by UGT2B17, and possibly UGT2B10, to 3HC-glucuronide. We investigated whether slower 3HC glucuronidation alters NMR, altering its ability to predict CYP2A6 activity and reducing its clinical utility. Methods Plasma NMR, three urinary NMRs, three urinary 3HC glucuronidation phenotypes and total nicotine equivalents were examined in 540 African American smokers. The UGT2B17 gene deletion and UGT2B10*2 were genotyped. Results The UGT2B17 gene deletion, but not UGT2B10*2 genotype, was associated with slower 3HC glucuronidation (indicated by three 3HC-glucuronidation phenotypes), indicating its role in this glucuronidation pathway. However, neither lower rates of 3HC glucuronidation, nor the presence of a UGT2B17 and UGT2B10 reduced function allele, altered plasma or urinary NMRs or levels of smoking. Conclusions Variation in 3HC glucuronidation activity, including these caused by UGT2B17 gene deletions, did not significantly alter NMR and is therefore unlikely to affect the clinical utility of NMR in smoking behavior and cessation studies. This study demonstrates that NMR is not altered by differences in the rate of 3HC glucuronidation, providing further support that NMR is a reliable indicator of CYP2A6 mediated nicotine metabolism.

Zhu, Andy Z. X.; Zhou, Qian; Cox, Lisa Sanderson; Ahluwalia, Jasjit S.; Benowitz, Neal L.; Tyndale, Rachel F.

2013-01-01

179

Improved detection of opioid use in chronic pain patients through monitoring of opioid glucuronides in urine.  

PubMed

When chronic pain patients are suspected of being non-compliant, their therapy can be withdrawn. Therefore, sensitive and specific confirmatory testing is important for identifying diversion and adherence. This work aimed to develop a novel liquid chromatography tandem mass spectrometry (LC-MS-MS) method to detect 14 opioids and six opioid glucuronide metabolites in urine with minimal sample preparation. Analytes included were morphine, oxymorphone, hydromorphone, oxycodone, hydrocodone, codeine, fentanyl, norfentanyl, 6-monoacetylmorphine, meperidine, normeperidine, propoxyphene, methadone, buprenorphine, morphine-3-glucuronide, morphine-6-glucuronide, oxymorphone glucuronide, hydromorphone glucuronide, codeine-6-glucuronide and norbuprenorphine glucuronide. Samples were processed by centrifugation and diluted in equal volume with a deuterated internal standard containing 14 opioids and four opioid glucuronides. The separation of all compounds was complete in nine minutes. The assay was linear between 10 and 1,000 ng/mL (fentanyl 0.25-25 ng/mL). Intra-assay imprecision (500 ng/mL, fentanyl 12.5 ng/mL) ranged from 1.0 to 8.4% coefficient of variation. Inter-assay precision ranged from 2.9 to 6.0%. Recovery was determined by spiking five patient specimens with opioid and opioid glucuronide standards at 100 ng/mL (fentanyl 2.5 ng/mL). Recoveries ranged from 82 to 107% (median 98.9%). The method correlated with our current quantitative LC-MS-MS assay for opioids, which employs different chromatography. Internal standards were not available for every analyte to critically evaluate for ion suppression. Instead, a novel approach was designed to achieve the most rigorous quality control possible, in which the recovery of each analyte was evaluated in each negative sample. PMID:22833646

Dickerson, Jane A; Laha, Thomas J; Pagano, Monica B; O'Donnell, Brendan R; Hoofnagle, Andrew N

2012-10-01

180

Structure-activity relationships of the glucuronidation of flavonoids by human glucuronosyltransferases.  

PubMed

With the increasing intake of flavonoids in diet, supplements and herbal medicines, studies on the biotransformation and disposition have been dramatically expanded. The current review covers the findings on the relationships between flavonoid structural properties and their glucuronidation activities in in vivo trials and in vitro human UGTs or microsomes for the past 2 decades. Regioselectivity and substrate specificity on the glucuronidation of flavonoids are summarized. The findings reveal the inconsistency from different studies and indicate the importance of in silico modeling in the prediction of structure-glucuronidation relationship. PMID:19663742

Wong, Yin Cheong; Zhang, Li; Lin, Ge; Zuo, Zhong

2009-11-01

181

Gas chromatographic-mass spectrometric assay for 6-hydroxymelatonin sulfate and 6-hydroxymelatonin glucuronide in urine  

SciTech Connect

Circulating melatonin is hydroxylated to 6-hydroxymelatonin and excreted in urine as the sulfate and glucuronide conjugates. We extracted these two compounds from urine by using octadecylsilane-bonded silica cartridges to eliminate most of the urea and electrolytes, and silica cartridges to separate the sulfate and glucuronide conjugates. After hydrolyzing the separated conjugates enzymically, we determined the free hydroxymelatonin by gas chromatography-mass spectrometry. Though recoveries were low and variable, we were able to quantify the analyte in the original sample by adding deuterated sulfate and glucuronide conjugates to the urines before extraction.

Francis, P.L.; Leone, A.M.; Young, I.M.; Stovell, P.; Silman, R.E.

1987-04-01

182

Ethyl`s MMT ready to hit the road  

Microsoft Academic Search

After spending two decades and about $30 million on the fight to sell the fuel octane booster methylcyclopentadienyl manganese tricarbonyl (MMT), Ethyl has started marketing the product. Ethyl president and chief operating officer Thomas Gottwald says he expects a profit from MMT from the outset. {open_quotes}MMT is a gangbuster new product,{close_quotes} says Paul Raman, an analyst with S.G. Warburg (New

1996-01-01

183

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

184

Glucuronidation of aurantio-obtusin: identification of human UDP-glucuronosyltransferases and species differences.  

PubMed

Abstract 1. The aurantio-obtusin's glucuronide was detected when aurantio-obtusin was incubated with human liver microsomes (HLMs). Recombinant UGT isoforms screening experiment showed that UGT1A8 was the major isoform contributed to the glucuronidation. 2. The metabolic profiles for aurantio-obtusin in liver microsomes from different species were similar, however, the intrinsic clearance values (Vmax/Km) among the species were: Monkey?>?Human?>?Rat?>?Rabbit?>?Dog?>?Pig?>?Mouse?>?Guinea pig. PMID:24618000

Mi, Bao-Li; Sun, Qi; Qu, Yan-Qing; Gao, Xiao-Xu; Yu, Zhen-Wen; Ge, Guang-Bo; Cai, Shan-Shan; Zhang, Jie; Zheng, Yan-Chao; Zhang, Zhen-Qiu

2014-08-01

185

Identification and Characterization of Human UDP-glucuronosyltransferases Responsible for the Glucuronidation of Fraxetin.  

PubMed

  Fraxetin, a major constituent of the traditional medicine plant Fraxinus rhynchophylla Hance (Oleaceae), has been found to possess multiple bioactivities. However, the metabolic pathway(s) of fraxetin in human tissues has not been reported yet. This study aimed to characterize the glucuronidation pathway(s) of fraxetin in human tissues. Fraxetin could be metabolized to two glucuronides in human liver microsomes (HLMs). These two glucuronides were biosynthesized and characterized as 7-O-glucuronide (7-O-G) and 8-O-glucuronide (8-O-G). UGT1A1, -1A6, -1A7, -1A8, -1A9 and -1A10 participated in the formation of 7-O-G, while the formation of 8-O-G was catalyzed selectively by UGT1A6 and UGT1A9. UGT1A9 showed the highest catalytic activities in the formation of 7-O-G and 8-O-G. Both kinetic characterization and inhibition assays demonstrated that UGT1A9 played important roles in fraxetin glucuronidations in HLMs, especially in the formation of the major metabolite 8-O-G. Furthermore, the intrinsic clearance of fraxetin in both human liver microsomes and UGT1A9 was greater than that of 7,8-dihydroxylcoumarin, revealing that the addition of a C-6 methoxy group led to the higher metabolic clearance. In summary, the glucuronidation pathways of fraxetin in human liver microsomes were well-characterized, and UGT1A9 was the major isoform responsible for the glucuronidations of fraxetin. PMID:24025985

Xia, Yang-Liu; Liang, Si-Cheng; Zhu, Liang-Liang; Ge, Guang-Bo; He, Gui-Yuan; Ning, Jing; Lv, Xia; Ma, Xiao-Chi; Yang, Ling; Yang, Sheng-Li

2014-04-25

186

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

Microsoft Academic Search

The usefulness of the direct 4-hour radioimmunoassay of estriol-16-glucuronide (EâG) and pregnanediol-3-glucuronide (PâG) 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 EâG and PâG profiles of 19

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

1984-01-01

187

Movement of Fluorescein and Its Glucuronide Across Retinal Pigment Epithelium-Choroid  

Microsoft Academic Search

Purpose. To characterize movement of fluorescein and its glucuronide across the blood-retinal barrier. Methods. Retinal pigment epithelium (RPE)-choroid preparations from New Zealand albino rabbit were sealed in an Ussing-type chamber in a stabilized condition for 3 hr, where move- ment of fluorescein and fluorescein glucuronide across the RPE-choroid was studied under a short circuit condition. Results. The outward (vitreous-choroid) permeability

Satoshi Koyano; Makoto Araie; Shuichiro Eguchi

188

A concise synthesis of glucuronide metabolites of urolithin-B, resveratrol, and hydroxytyrosol  

Microsoft Academic Search

A simple and direct strategy to chemically synthesize O-?-d-glucuronides of urolithin-B 4, resveratrol 5, and the corresponding hydroxytyrosol derivatives 6, 7 (as a regioisomeric mixture), and 8 is described. The critical glycosylation step has been optimized using a structurally simple phenol, urolithin-B, by modification of several reaction parameters (solvent, promoter, and glucuronide donor). Very high yields have been obtained in

Ricardo Lucas; David Alcantara; Juan Carlos Morales

2009-01-01

189

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

190

Affinity profiles of morphine, codeine, dihydrocodeine and their glucuronides at opioid receptor subtypes  

Microsoft Academic Search

The affinity of morphine, codeine, dihydrocodeine and their glucuronides for ?-, ?,- and ?-opioid receptors was investigated. Binding was studied on guinea-pig brain homogenates with [3H]DAMGO, [3H]DPDPE, and [3H]U69593. The substitution of the free phenolic group of morphine caused a decrease in binding at opioid receptors without affecting the ??-ratio nor that of ??. Glucuronidation of the 6-hydroxyl group of

Christian Mignat; Uta Wille; Albrecht Ziegler

1995-01-01

191

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

192

beta Glucuronidase Catalyzed Hydrolysis of Benzo[a]pyrene-3Glucuronide and Binding to DNA  

Microsoft Academic Search

beta -Glucuronidase catalyzes the hydrolysis of benzo[a]pyrene-3-glucuronide to 3-hydroxybenzo[a]pyrene. During the enzymatic hydrolysis, a benzo[a]pyrene derivative is formed which binds to DNA to a far greater extent than either the 3-hydroxybenzo[a]pyrene or its glucuronide. These results suggest that conjugates of benzo[a]pyrene may be converted by beta -glucuronidase at intracellular and organ sites distal to the initial sites of oxygenation and

Nadao Kinoshita; Harry V. Gelboin

1978-01-01

193

Glucuronidation of Drugs and Drug-Induced Toxicity in Humanized UDP-Glucuronosyltransferase 1 Mice.  

PubMed

UDP-glucuronosyltransferases (UGTs) are phase II drug-metabolizing enzymes that catalyze glucuronidation of various drugs. Although experimental rodents are used in preclinical studies to predict glucuronidation and toxicity of drugs in humans, species differences in glucuronidation and drug-induced toxicity have been reported. Humanized UGT1 mice in which the original Ugt1 locus was disrupted and replaced with the human UGT1 locus (hUGT1 mice) were recently developed. In this study, acyl-glucuronidations of etodolac, diclofenac, and ibuprofen in liver microsomes of hUGT1 mice were examined and compared with those of humans and regular mice. The kinetics of etodolac, diclofenac, and ibuprofen acyl-glucuronidation in hUGT1 mice were almost comparable to those in humans, rather than in mice. We further investigated the hepatotoxicity of ibuprofen in hUGT1 mice and regular mice by measuring serum alanine amino transferase (ALT) levels. Because ALT levels were increased at 6 hours after dosing in hUGT1 mice and at 24 hours after dosing in regular mice, the onset pattern of ibuprofen-induced liver toxicity in hUGT1 mice was different from that in regular mice. These data suggest that hUGT1 mice can be valuable tools for understanding glucuronidations of drugs and drug-induced toxicity in humans. PMID:24764149

Kutsuno, Yuki; Itoh, Tomoo; Tukey, Robert H; Fujiwara, Ryoichi

2014-07-01

194

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

195

Direct MS-MS identification of isoxsuprine-glucuronide in post-administration equine urine.  

PubMed Central

Isoxsuprine is routinely recovered from enzymatically-hydrolyzed, post-administration urine samples as parent isoxsuprine in equine forensic science. However, the specific identity of the material in horse urine from which isoxsuprine is recovered has never been established, although it has long been assumed to be a glucuronide conjugate (or conjugates) of isoxsuprine. Using ESI/MS/MS positive mode as an analytical tool, urine samples collected 4-8 h after isoxsuprine administration yielded a major peak at m/z 554 that was absent from control samples and resisted fragmentation to daughter ions. Titration of this material with increasing concentrations of sodium acetate yielded m/z peaks consistent with the presence of monosodium and disodium isoxsuprine-glucuronide complexes, suggesting that the starting material was a dipotassium-isoxsuprine-glucuronide complex. Electrospray ionization mass spectrometry negative mode disclosed the presence of a m/z 476 peak that declined following enzymatic hydrolysis and resulted in the concomitant appearance of peaks at m/z 300 and 175. The resulting peaks were consistent with the presence of isoxsuprine (m/z 300) and a glucuronic acid residue (m/z 175). Examination of the daughter ion spectrum of this putative isoxsuprine-glucuronide m/z 476 peak showed overlap of many peaks with those of similar spectra of authentic morphine-3- and morphine-6-glucuronides, suggesting they were derived from glucuronic acid conjugation. These data suggest that isoxsuprine occurs in post-administration urine samples as an isoxsuprine-glucuronide conjugate and also, under some circumstances, as an isoxsuprine-glucuronide-dipotassium complex.

Bosken, J M; Lehner, A F; Hunsucker, A; Harkins, J D; Woods, W E; Karpiesiuk, W; Carter, W G; Boyles, J; Fisher, M; Tobin, T

2000-01-01

196

21 CFR 584.200 - Ethyl alcohol containing ethyl acetate.  

Code of Federal Regulations, 2013 CFR

...added the equivalent of 4.25 gallons of 100 percent ethyl acetate. It is used in accordance with good feeding practices in ruminant feed supplements as a source of added energy. [46 FR 52333, Oct. 27, 1981, as amended at 72 FR 41620, July 31,...

2013-04-01

197

Blood-brain distribution of morphine-6-glucuronide in sheep  

PubMed Central

Background and purpose: At present there are few data regarding the rate and extent of brain–blood partitioning of the opioid active metabolite of morphine, morphine-6-glucuronide (M6G). In this study the cerebral kinetics of M6G were determined, after a short-term intravenous infusion, in chronically instrumented conscious sheep. Experimental approach: Five sheep received an intravenous infusion of M6G 2.2 mg kg-1 over a four-minute period. Non-linear mixed-effects analysis, with hybrid physiologically based kinetic models, was used to estimate cerebral kinetics from the arterio-sagittal sinus concentration gradients and cerebral blood flow measurements. Key results: A membrane limited model was selected as the final model. The blood-brain equilibration of M6G was relatively slow (time to reach 50% equilibration of the deep compartment 5.8 min), with low membrane permeability (PS, population mean, 2.5 ml min-1) from the initial compartment (V1, 13.7 ml) to a small deep distribution volume (V2) of 18.4 ml. There was some between-animal variability (%CV) in the initial distribution volume (29%), but this was not identified for PS or V2. Conclusion and Implications: Pharmacokinetic modelling of M6G showed a delayed equilibration between brain and blood of a nature that is primarily limited by permeability across the blood-brain-barrier, in accordance with its physico-chemical properties.

Villesen, H H; Foster, D J R; Upton, R N; Christrup, L L; Somogyi, A A; Martinez, A; Grant, C

2006-01-01

198

Identification of human UDP-glucuronosyltransferases involved in N-carbamoyl glucuronidation of lorcaserin.  

PubMed

Lorcaserin, a selective serotonin 5-HT(2C) receptor agonist, is a weight management agent in clinical development. Lorcaserin N-carbamoyl glucuronidation governs the predominant excretory pathway of lorcaserin in humans. Human UDP-glucuronosyltransferases (UGTs) responsible for lorcaserin N-carbamoyl glucuronidation are identified herein. Lorcaserin N-carbamoyl glucuronide formation was characterized by the following approaches: metabolic screening using human tissues (liver, kidney, intestine, and lung) and recombinant enzymes, kinetic analyses, and inhibition studies. Whereas microsomes from all human tissues studied herein were found to be catalytically active for lorcaserin N-carbamoyl glucuronidation, liver microsomes were the most efficient. With recombinant UGT enzymes, lorcaserin N-carbamoyl glucuronidation was predominantly catalyzed by three UGT2Bs (UGT2B7, UGT2B15, and UGT2B17), whereas two UGT1As (UGT1A6 and UGT1A9) played a minor role. UGT2B15 was most efficient, with an apparent K(m) value of 51.6 ± 1.9 ?M and V(max) value of 237.4 ± 2.8 pmol/mg protein/min. The rank order of catalytic efficiency of human UGT enzymes for lorcaserin N-carbamoyl glucuronidation was UGT2B15 > UGT2B7 > UGT2B17 > UGT1A9 > UGT1A6. Inhibition of lorcaserin N-carbamoyl glucuronidation activities of UGT2B7, UGT2B15, and UGT2B17 in human liver microsomes by mefenamic acid, bisphenol A, and eugenol further substantiated the involvement of these UGT2B isoforms. In conclusion, multiple human UGT enzymes catalyze N-carbamoyl glucuronidation of lorcaserin; therefore, it is unlikely that inhibition of any one of these UGT activities will lead to significant inhibition of the lorcaserin N-carbamoyl glucuronidation pathway. Thus, the potential for drug-drug interaction by concomitant administration of a drug(s) that is metabolized by any of these UGTs is remote. PMID:22259019

Sadeque, Abu J M; Usmani, Khawja A; Palamar, Safet; Cerny, Matthew A; Chen, Weichao G

2012-04-01

199

Molecular Structure of Ethyl cyclotene  

NSDL National Science Digital Library

Ethyl Cyclotene has a similar odor and flavor to Cyclotene. It is naturally found in coffee and tobacco. As a food additive, this compound has a very strong maple odor and taste. It contributes to the fragrance of rum and whiskey.

2006-09-18

200

Detection of interstellar ethyl cyanide  

NASA Technical Reports Server (NTRS)

Twenty-four millimeter-wave emission lines of ethyl cyanide (CH3CH2CN) have been detected in the Orion Nebula (OMC-1) and seven in Sgr B2. To derive precise radial velocities from the astronomical data, a laboratory measurement of the rotational spectrum of ethyl cyanide has been made at frequencies above 41 GHz. In OMC-1, the rotational temperature of ethyl cyanide is 90 K (in good agreement with other molecules), the local-standard-of-rest radial velocity is 4.5 + or - 1.0 km/s (versus 8.5 km/s for most molecules), and the column density is 1.8 by 10 to the 14th power per sq cm (a surprisingly high figure for a complicated molecule). The high abundance of ethyl cyanide in the Orion Nebula suggests that ethane and perhaps larger saturated hydrocarbons may be common constituents of molecular clouds and have escaped detection only because they are nonpolar or only weakly polar.

Johnson, D. R.; Lovas, F. J.; Gottlieb, C. A.; Gottlieb, E. W.; Litvak, M. M.; Thaddeus, P.; Guelin, M.

1977-01-01

201

Separation and Purification of Two Flavone Glucuronides from Erigeron multiradiatus (Lindl.) Benth with Macroporous Resins  

PubMed Central

Scutellarein-7-O-?-D-glucuronide (SG) and apigenin-7-O-?-D-glucuronide (AG) are two major bioactive constituents with known pharmacological effects in Erigeron multiradiatus. In this study, a simple method for preparative separation of the two flavone glucuronides was established with macroporous resins. The performance and adsorption characteristics of eight macroporous resins including AB-8, HPD100, HPD450, HPD600, D100, D101, D141, and D160 have been evaluated. The results confirmed that D141 resin offered the best adsorption and desorption capacities and the highest desorption ratio for the two glucuronides among the tested resins. Sorption isotherms were constructed for D141 resin under optimal ethanol conditions and fitted well to the Freundlich and Langmuir models (R2 > 0.95). Dynamic adsorption and desorption tests was performed on column packed with D141 resin. After one-run treatment with D141 resin, the two-constituent content in the final product was increased from 2.14% and 1.34% in the crude extract of Erigeron multiradiatus to 24.63% and 18.42% in the final products with the recoveries of 82.5% and 85.4%, respectively. The preparative separation of SG and AG can be easily and effectively achieved via adsorption and desorption on D141 resin, and the method developed can be referenced for large-scale separation and purification of flavone glucuronides from herbal raw materials.

Zhang, Zhi-feng; Liu, Yuan; Luo, Pei; Zhang, Hao

2009-01-01

202

Genetic and environmental factors associated with variation of human xenobiotic glucuronidation and sulfation.  

PubMed Central

Glucuronidation and sulfation are phase 2 metabolic reactions catalyzed by large families of different isoenzymes in man. The textbook view that glucuronidation and sulfation lead to the production of harmless conjugates for simple excretion is not valid. Biologically active and toxic sulfates and glucuronides are produced and leed to adverse drug reactions, including immune hypersensitivity. Considerable variation in xenobiotic conjugation is observed as a result of altered expression of UDP-glucuronosyltransferases (UGTs) and sulfotransferases (STs). Recent cloning and expression of human cDNA encoding UGTs and STs has facilitated characterization of isoform substrate specificity, which has been further validated using specific antibodies and human tissue fractions. The availability of cloned/expressed human enzymes and specific antibodies has enabled the investigation of xenobiotic induction and metabolic disruption leeding to adverse responses. Genetic polymorphisms of glucuronidation and sulfation are known to exist although the characterization and assessment of the importance of these variations are hampered by appropriate ethical studies in men with suitable safe model compounds. Genetic analysis has allowed molecular identification of defects in well-known hyperbilirubinemias. However, full characterization of the specific functional roles of human UGTs and STs requires rigorous kinetic and molecular analyses of the role of each enzyme in vivo through the use of specific antibodies and inhibitors. This will leed to the better prediction of variation of xenobiotic glucuronidation and sulfation in man.

Burchell, B; Coughtrie, M W

1997-01-01

203

Effect of diethylether on the formation of paracetamol sulphate and glucuronide in isolated rat hepatocytes.  

PubMed

Diethylether has previously been shown to inhibit several pathways of drug metabolism, including conjugation of paracetamol in isolated rat hepatocytes. Since overall paracetamol conjugation consists of pathways of different subcellular localization (cytosolar sulphation and microsomal glucuronidation) the response of both pathways to diethylether was tested. The elimination of paracetamol (160 mumol/l, initial concentration) and the formation of paracetamol sulphate and glucuronide were measured (high-performance liquid chromatography) in suspensions of isolated rat hepatocytes from fasted and fed animals over 1 h in the absence and presence of diethylether (30 mmol/l). Approximately 90% of the paracetamol elimination was by sulphation and nearly 10% by glucuronidation both in the controls and in the presence of ether. The overall disposition of paracetamol and the formation of sulphate were both reduced by about 50% in the presence of ether compared to the controls while the formation of glucuronide was reduced by 70%. The results were not influenced by the nutritional state of the animals before sacrifice. It is concluded that the inhibitory effect of ether on total paracetamol metabolism was mainly caused by reduced sulphation. Since microsomal glucuronidation was also inhibited by ether, both cytosolar and microsomal enzyme systems were sensitive to diethylether. PMID:6709689

Aune, H; Hals, P A; Hansen, B I; Aarbakke, J

1984-01-01

204

21 CFR 172.868 - Ethyl cellulose.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Ethyl cellulose. 172.868 Section 172.868 Food and...Multipurpose Additives § 172.868 Ethyl cellulose. The food additive ethyl cellulose may be safely used in food in accordance...

2009-04-01

205

21 CFR 172.868 - Ethyl cellulose.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2009-04-01 true Ethyl cellulose. 172.868 Section 172.868 Food and...Multipurpose Additives § 172.868 Ethyl cellulose. The food additive ethyl cellulose may be safely used in food in accordance...

2010-01-01

206

21 CFR 573.420 - Ethyl cellulose.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Ethyl cellulose. 573.420 Section 573.420 Food and...Food Additive Listing § 573.420 Ethyl cellulose. The food additive ethyl cellulose may be safely used in animal feed in...

2010-04-01

207

21 CFR 573.420 - Ethyl cellulose.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Ethyl cellulose. 573.420 Section 573.420 Food and...Food Additive Listing § 573.420 Ethyl cellulose. The food additive ethyl cellulose may be safely used in animal feed in...

2013-04-01

208

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

2013-11-13

209

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

210

Expanded Utility of the ?-Glucuronide Linker: ADCs That Deliver Phenolic Cytotoxic Agents  

PubMed Central

The ?-glucuronide linker has been used for antibody?drug conjugates (ADCs) to deliver amine-containing cytotoxic agents. The linker is stable in circulation, hydrophilic and provides ADCs that are highly active in vitro and in vivo. To extend the utility of the ?-glucuronide linker toward phenol-containing drugs, an N,N?-dimethylethylene diamine self-immolative spacer was incorporated with the linker for release of the potent cytotoxic phenol psymberin A. Exposure of the drug-linker to ?-glucuronidase resulted in facile drug release. The corresponding ADCs were active and immunologically selective against CD30-positive L540cy and CD70-positive Caki-1 cell lines.

2010-01-01

211

Chemical synthesis and characterization of epicatechin glucuronides and sulfates: bioanalytical standards for epicatechin metabolite identification.  

PubMed

The monoglucuronides and sulfates of epicatechin, 3'-O-methylepicatechin, and 4'-O-methylepicatechin, respectively, were synthesized as authentic bioanalytical standards. Reversed-phase HPLC methods capable of baseline separation of the glucuronides and sulfates have been developed. Both the epicatechin glucuronides and sulfates were stable in the solid state when stored under ambient conditions and in aqueous solution when stored refrigerated. These results should prove invaluable to the research community as analytical standards as well as in future studies of the biological and pharmacological effects of epicatechin in humans. PMID:23356946

Zhang, Mingbao; Jagdmann, G Erik; Van Zandt, Michael; Sheeler, Ryan; Beckett, Paul; Schroeter, Hagen

2013-02-22

212

Urinary Excretion of Buprenorphine, Norbuprenorphine, Buprenorphine-Glucuronide, and Norbuprenorphine-Glucuronide in Pregnant Women Receiving Buprenorphine Maintenance Treatment  

PubMed Central

BACKGROUND Buprenorphine (BUP) is under investigation as a medication therapy for opioid-dependent pregnant women. We investigated BUP and metabolite disposition in urine from women maintained on BUP during the second and third trimesters of pregnancy and postpartum. METHODS We measured BUP, norbuprenorphine (NBUP), buprenorphine glucuronide (BUP-Gluc), and NBUP-Gluc concentrations in 515 urine specimens collected thrice weekly from 9 women during pregnancy and postpartum. Specimens were analyzed using a fully validated liquid chromatography-mass spectrometry method with limits of quantification of 5 µg/L for BUP and BUP-Gluc and 25 µg/L for NBUP and its conjugated metabolite. We examined ratios of metabolites across trimesters and postpartum to identify possible changes in metabolism during pregnancy. RESULTS NBUP-Gluc was the primary metabolite identified in urine and exceeded BUP-Gluc concentrations in 99% of specimens. Whereas BUP-Gluc was identified in more specimens than NBUP, NBUP exceeded BUP-Gluc concentrations in 77.9% of specimens that contained both analytes. Among all participants, the mean BUP-Gluc:NBUP-Gluc ratio was significantly higher in the second trimester compared to the third trimester, and there were significant intrasubject differences between trimesters in 71% of participants. In 3 women, the percent daily dose excreted was higher during pregnancy than postpregnancy, consistent with other data indicating increased renal elimination of drugs during pregnancy. CONCLUSIONS These data are the first to evaluate urinary disposition of BUP and metabolites in a cohort of pregnant women. Variable BUP excretion during pregnancy may indicate metabolic changes requiring dose adjustment during later stages of gestation.

Kacinko, Sherri L.; Jones, Hendree E.; Johnson, Rolley E.; Choo, Robin E.; Concheiro-Guisan, Marta; Huestis, Marilyn A.

2011-01-01

213

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

2013-03-10

214

Monitoring population levels of alcohol consumption in pregnant women: a case for using biomarkers.  

PubMed

A challenge to biochemically monitoring alcohol consumption in pregnancy is the prohibitive costs of collecting thousands of blood samples. This pilot study looks at the feasibility of using residual samples to monitor chronic and acute alcohol consumption in pregnancy. Residual anomalies screening samples (n = 150, 2006/7) were tested for carbohydrate-deficient transferrin (CDT, chronic marker) and ethyl glucuronide (EtG, acute marker). Valid readings were obtained for CDT but not EtG. These results pave the way for a larger representative study, to provide, for the first time, a national biochemical baseline estimate of chronic alcohol consumption in the pregnant population. PMID:23750658

Shipton, Deborah; Tappin, David; Sherwood, Roy; Mactier, Helen; Aitken, David; Crossley, Jenny

2013-06-01

215

The Escherichia coli glucuronylsynthase promoted synthesis of steroid glucuronides: improved practicality and broader scope.  

PubMed

A library of steroid glucuronides was prepared using the glucuronylsynthase derived from Escherichia coli?-glucuronidase, followed by purification using solid-phase extraction. A representative range of steroid substrates were screened for synthesis on the milligram scale under optimised conditions with conversions dependent on steroid substitution and stereochemistry. Epiandrosterone (3?-hydroxy-5?-androstan-17-one) provided the highest conversion of 90% (84% isolated yield). The previously unreported glucuronide conjugates of methandriol (17?-methylandrost-5-ene-3?,17?-diol), cholest-5-ene-3?,25-diol and the designer steroid trenazone (17?-hydroxyestra-4,9-dien-3-one) were prepared on a multi-milligram scale suitable for characterisation by (1)H and (13)C NMR spectroscopy. The glucuronide conjugate of d5-etiocholanolone (2,2,3,4,4-d5-3?-hydroxy-5?-androstan-17-one), a target developed by the World Anti-Doping Agency as a certified reference material, was also prepared on a milligram scale. The improved E. coli glucuronylsynthase method provides for the rapid synthesis and purification of steroid glucuronides on a scale suitable for a range of analytical applications. PMID:25001892

Ma, Paul; Kanizaj, Nicholas; Chan, Shu-Ann; Ollis, David L; McLeod, Malcolm D

2014-08-28

216

Diclofenac acyl glucuronide, a major biliary metabolite, is directly involved in small intestinal injury in rats  

Microsoft Academic Search

Background & Aims: Enterohepatic recirculation of nonsteroidal anti-inflammatory drugs is a critical factor in the pathogenesis of intestinal injury, but the underlying mechanism of toxicity remains obscure. The aim of this study was to examine the role of diclofenac acyl glucuronide, which is the major biliary metabolite and is chemically reactive, in the precipitation of small intestinal ulceration. Methods: Hepatocanalicular

Sven Seitz; Urs A. Boelsterli

1998-01-01

217

Differences in the glucuronidation of resveratrol and pterostilbene: altered enzyme specificity and potential gender differences.  

PubMed

  Resveratrol, a natural polyphenol found in grapes, berries and other plants, has been proposed as an ideal chemopreventative agent due to its plethora of health promoting activities. However, despite its lofty promise as a cancer prevention agent its success in human clinical trials has been limited due to its poor bioavailability. Thus, interest in other natural polyphenols is intensifying including the naturally occurring dimethylated analog of resveratrol, pterostilbene. The UDP-glucuronosyltransferase (UGT) family of enzymes plays a vital role in the metabolism of both resveratrol and pterostilbene. The current study sought to elucidate the UGT family members responsible for the metabolism of pterostilbene and to examine gender differences in the glucuronidation of resveratrol and pterostilbene. We demonstrate that UGT1A1 and UGT1A3 are mainly responsible for pterostilbene glucuronidation although UGT1A8, UGT1A9 and UGT1A10 also had detectable activity. Intriguingly, UGT1A1 exhibits the highest activity against both resveratrol and pterostilbene despite altered hydroxyl group specificity. Using pooled human liver microsomes, enzyme kinetics were determined for pterostilbene and resveratrol glucuronides. In all cases females were more efficient than males, indicating potential gender differences in stilbene metabolism. Importantly, the glucuronidation of pterostilbene is much less efficient than that of resveratrol, indicating that pterostilbene will have dramatically decreased metabolism in humans. PMID:23965644

Dellinger, Ryan W; Garcia, Angela M Gomez; Meyskens, Frank L

2014-04-25

218

Glucuronidation and subsequent biliary excretion of mycophenolic acid in rat sandwich-cultured hepatocytes.  

PubMed

Rat sandwich-cultured hepatocytes (SCH) were used to correlate the in vitro hepatic disposition of mycophenolic acid (MPA) with published in vivo data, as well as mechanistic studies on drug-drug interaction. The major metabolite of MPA in SCH was 7-O-glucuronide (MPAG) followed by acyl-glucuronide (AcMPAG). MPAG and AcMPAG, but not MPA, showed significant in vitro biliary excretion with biliary excretion indexes (BEI) of 40% for MPAG and 45% for AcMPAG. While these BEIs were similar, the biliary excretion amount (BEA) of MPAG (120 pmol/mg protein) was orders of magnitude higher than that of AcMPAG (0.34 pmol/mg protein). Since MPAG is the major metabolite in in vivo bile, we propose that BEA is a better qualifier of biliary excretion. Quercetin inhibited MPAG and AcMPAG production, while chrysin inhibited only MPAG production, showing that chrysin is not a pan-glucuronidation inhibitor. Cyclosporin A (CysA) reduced the BEI of MPAG and increased intracellular MPA accumulation without changing MPAG amounts. These results suggest that CysA causes inhibition of biliary excretion of MPAG, as well as a mixed inhibition of glucuronidation of MPA and sinusoidal efflux of MPA/MPAG. In conclusion, the present study demonstrates a good agreement of hepatic MPA disposition between SCH and in vivo rats. PMID:24025987

Tetsuka, Kazuhiro; Gerst, Nicolas; Tamura, Kouichi; Masters, Jeffrey N

2014-01-01

219

EVALUATION OF INDOXYL-B-D GLUCURONIDE AS A CHROMOGEN IN MEDIA SPECIFIC FOR ESCHERICHIA COLI  

EPA Science Inventory

Indoxyl-beta D-glucuronide was evaluated as a specific chromogen for detection of Escherichia coli by the membrane filter method. n all 487 colonies were tested from the indoxyl supplemented media yielding 82.9% verification as E. coli. ompared to the indoxyl medium other media p...

220

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

2013-05-01

221

Nitrosation of glycine ethyl ester and ethyl diazoacetate to give the alkylating agent and mutagen ethyl chloro(hydroximino)acetate.  

PubMed

Whereas nitrosation of secondary amines produces nitrosamines, amino acids with primary amino groups and glycine ethyl ester were reported to react with nitrite to give unidentified agents that alkylated 4-(p-nitrobenzyl)pyridine to produce purple dyes and be direct mutagens in the Ames test. We report here that treatment of glycine ethyl ester at 37 degrees C with excess nitrite acidified with HCl, followed by ether extraction, gave 30-40% yields of a product identified as ethyl chloro(hydroximino)acetate [ClC(=NOH)COOEt, ECHA] and a 9% yield of ethyl chloroacetate. The ECHA was identical to that synthesized by a known method from ethyl acetoacetate, strongly alkylated nitrobenzylpyridine, and may have arisen by N-nitrosation of glycine ethyl ester to give ethyl diazoacetate, which was C-nitrosated and reacted with chloride to give ECHA. Nitrosation of ethyl diazoacetate also yielded ECHA. Ethyl nitroacetate was not an intermediate as its nitrosation did not produce ECHA. ECHA reacted with aniline to give ethyl (hydroxamino)(phenylimino)acetate [PhN=C(NHOH)CO2Et]. This product was different from ethyl [(phenylamino)carbonyl]carbamate [PhNHC(=O)NHCO2Et], which was synthesized by reacting ethyl isocyanatoformate (OCN.CO2Et) with aniline. ECHA reacted with guanosine to give a derivative, which may have been a guanine-C(=NOH)CO2Et derivative. ECHA showed moderate toxicity and weak but significant mutagenicity without activation in Salmonella typhimurium TA-100 (mean, 1.31 x control value for 12-18 microg/plats) and for V79 mammalian cells (1.5-1.7 x control value for 60-100 microM). In conclusion, gastric nitrosation of glycine derivatives such as peptides with a N-terminal glycine might produce ECHA analogues that alkylate bases of gastric mucosal DNA and thereby initiate gastric cancer. PMID:15025513

Zhou, Lin; Haorah, James; Chen, Sheng C; Wang, Xiaojie; Kolar, Carol; Lawson, Terence A; Mirvish, Sidney S

2004-03-01

222

A New Strategy to Rapidly Evaluate Kinetics of Glucuronide Efflux by Breast Cancer Resistance Protein (BCRP/ABCG2)  

PubMed Central

Purpose The efflux transporter breast cancer resistance protein (BCRP/ABCG2) plays an important role in excretion of anionic drugs and metabolites including glucuronides in humans. Methods In this article, our recently published cell model (i.e., HeLa cells over-expressing UGT1A9 (HeLa1A9)) is used to determine the kinetic parameters of BCRP-mediated transport of glucuronides. Results After incubation of the aglycone with the cells, a steady-state (i.e., zero-order or near zero-order) excretion of its glucuronide is rapidly achieved and then maintained. Kinetic profiling with different (intracellular) glucuronide concentrations and their corresponding excretion rates is enabled by varying the concentration of the aglycone, which allows for the determination of kinetic parameters responsible for BCRP-mediated efflux of glucuronides. This approach was validated theoretically using a cellular pharmacokinetic model incorporating various enzymatic and transporter-mediated kinetic processes. It was also validated experimentally in that kinetic parameters of efflux of glucuronides of 6-hydroxyflavone and 4-methylumberiferone in the HeLa1A9 cell model were shown to be consistent with those derived with BCRP-overexpressing membrane vesicles. Conclusion This study provides a new strategy for rapidly evaluating the kinetics of glucuronide efflux by BCRP.

Wu, Baojian; Jiang, Wen; Yin, Taijun; Gao, Song

2013-01-01

223

Glucuronidation by UGT1A1 Is the Dominant Pathway of the Metabolic Disposition of Belinostat in Liver Cancer Patients  

PubMed Central

Belinostat is a hydroxamate class HDAC inhibitor that has demonstrated activity in peripheral T-cell lymphoma and is undergoing clinical trials for non-hematologic malignancies. We studied the pharmacokinetics of belinostat in hepatocellular carcinoma patients to determine the main pathway of metabolism of belinostat. The pharmacokinetics of belinostat in liver cancer patients were characterized by rapid plasma clearance of belinostat with extensive metabolism with more than 4-fold greater relative systemic exposure of major metabolite, belinostat glucuronide than that of belinostat. There was significant interindividual variability of belinostat glucuronidation. The major pathway of metabolism involves UGT1A1-mediated glucuronidation and a good correlation has been identified between belinostat glucuronide formation and glucuronidation of known UGT1A1 substrates. In addition, liver microsomes harboring UGT1A1*28 alleles have lower glucuronidation activity for belinostat compared to those with wildtype UGT1A1. The main metabolic pathway of belinostat is through glucuronidation mediated primarily by UGT1A1, a highly polymorphic enzyme. The clinical significance of this finding remains to be determined. Trial Registration ClinicalTrials.gov NCT00321594

Wang, Ling-Zhi; Ramirez, Jacqueline; Yeo, Winnie; Chan, Mei-Yi Michelle; Thuya, Win-Lwin; Lau, Jie-Ying Amelia; Wan, Seow-Ching; Wong, Andrea Li-Ann; Zee, Ying-Kiat; Lim, Robert; Lee, Soo-Chin; Ho, Paul C.; Lee, How-Sung; Chan, Anthony; Ansher, Sherry; Ratain, Mark J.; Goh, Boon-Cher

2013-01-01

224

Characterization of UGTs Active against SAHA and Association between SAHA Glucuronidation Activity Phenotype with UGT Genotype  

PubMed Central

Suberoylanilide hydroxamic acid (SAHA) is a histone deacetylase inhibitor used in the treatment of cutaneous T-cell lymphoma and in clinical trials for treatment of multiple other cancers. A major mode of SAHA metabolism is by glucuronidation via the UDP-glucuronosyltransferase (UGT) family of enzymes. To characterize the UGTs active against SAHA, homogenates from HEK293 cell lines overexpressing UGT wild-type or variant UGT were used. The hepatic UGTs 2B17 and 1A9 and the extrahepatic UGTs 1A8 and 1A10 exhibited the highest overall activity against SAHA as determined by Vmax/KM (16 ± 6.5, 7.1 ± 2.2, 33 ± 6.3, and 24 ± 2.4 nL·min?1.?g UGT protein?1, respectively), with UGT2B17 exhibiting the lowest KM (300 ?mol/L) against SAHA of any UGT in vitro. Whereas the UGT1A8p.Ala173Gly variant exhibited a 3-fold (P < 0.005) decrease in glucuronidation activity against SAHA compared with wild-type UGT1A8, the UGT1A8p.Cys277Tyr variant exhibited no detectable glucuronidation activity; a similar lack of detectable glucuronidation activity was observed for the UGT1A10p.Gly139Lys variant. To analyze the effects of the UGT2B17 gene deletion variant (UGT2B17*2) on SAHA glucuronidation phenotype, human liver microsomes (HLM) were analyzed for glucuronidation activity against SAHA and compared with UGT2B17 genotype. HLM from subjects homozygous for UGT2B17*2 exhibited a 45% (P < 0.01) decrease in glucuronidation activity and a 75% (P < 0.002) increase in KM compared with HLMs from subjects homozygous for the wild-type UGT2B17*1 allele. Overall, these results suggest that several UGTs play an important role in the metabolism of SAHA and that UGT2B17-null individuals could potentially exhibit altered SAHA clearance rates with differences in overall response.

Balliet, Renee M.; Chen, Gang; Gallagher, Carla J.; Dellinger, Ryan W.; Sun, Dongxiao; Lazarus, Philip

2009-01-01

225

Glucuronidation and Covalent Protein Binding of Benoxaprofen and Flunoxaprofen in Sandwich-Cultured Rat and Human Hepatocytes  

PubMed Central

Benoxaprofen (BNX), a nonsteroidal anti-inflammatory drug (NSAID) that was withdrawn because of hepatotoxicity, is more toxic than its structural analog flunoxaprofen (FLX) in humans and rats. Acyl glucuronides have been hypothesized to be reactive metabolites and may be associated with toxicity. Both time- and concentration-dependent glucuronidation and covalent binding of BNX, FLX, and ibuprofen (IBP) were determined by exposing sandwich-cultured rat hepatocytes to each NSAID. The levels of glucuronide and covalent protein adduct measured in cells followed the order BNX > FLX > IBP. These results indicate that 1) BNX-glucuronide (G) is more reactive than FLX-G, and 2) IBP-G is the least reactive metabolite, which support previous in vivo studies in rats. The proportional increases of protein adduct formation for BNX, FLX, and IBP as acyl glucuronidation increased also support the hypothesis that part of the covalent binding of all three NSAIDs to hepatic proteins is acyl glucuronide-dependent. Moreover, theses studies confirmed the feasibility of using sandwich-cultured rat hepatocytes for studying glucuronidation and covalent binding to hepatocellular proteins. These studies also showed that these in vitro methods can be applied using human tissues for the study of acyl glucuronide reactivity. More BNX-protein adduct was formed in sandwich-cultured human hepatocytes than FLX-protein adduct, which not only agreed with its relative toxicity in humans but also was consistent with the in vitro findings using rat hepatocyte cultures. These data support the use of sandwich-cultured human hepatocytes as an in vitro screening model of acyl glucuronide exposure and reactivity.

Dong, Jennifer Q.

2009-01-01

226

Development of an automated synthesis system for preparation of glucuronides using a solid-phase extraction column loaded with microsomes.  

PubMed

An automated synthesis system using a solid-phase extraction (SPE) system and column packed with octadecylsilica (ODS), which was coated with phospholipid and loaded with dog liver microsomes, was developed for synthesis of glucuronides. Preparation of the microsome-immobilized SPE column, glucuronidation of drugs to synthesize the glucuronides and elution of the products were performed by an automated synthesis system. The phospholipid-coated SPE column and then the microsome-immobilized SPE column were readily prepared by allowing a solution containing L-alpha-dipalmitoylphosphatidylcholine to flow through the SPE column, and then by recycling a buffer solution containing dog liver microsomes through the resulting phospholipid-coated SPE column. The microsome-immobilized SPE column exhibiting the uridine diphosphate (UDP)-glucuronosyltransferase activity catalyzed the glucuronidation of mefenamic acid and estradiol to the corresponding glucuronides in the presence of UDP-glucuronic acid, and three glucuronides of mefenamic acid and estradiol were synthesized using the automated synthesis system, by simply recycling a buffer solution containing UDP-glucuronic acid through the microsome-immobilized SPE column loaded with the substrate. We used beta-cyclodextrin as a solubilizing agent for the synthesis of the glucuronides of estradiol that is practically insoluble in aqueous solutions. The productivity of these glucuronides using the microsome-immobilized SPE column was higher than that using the free microsomes (batch method). Furthermore, we developed a fully automated synthesis-isolation system by coupling the automated synthesis system to an automated preparative HPLC system. The automated synthesis system as well as the fully automated synthesis-isolation system should be very useful for synthesizing glucuronides for drug development. PMID:20190440

Kashima, Yousuke; Kitade, Takashi; Kashima, Yuuko; Okabayashi, Yoshito

2010-03-01

227

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

228

Biotransformation of bisphenol AF to its major glucuronide metabolite reduces estrogenic activity.  

PubMed

Bisphenol AF (BPAF), an endocrine disrupting chemical, can induce estrogenic activity through binding to estrogen receptor (ER). However, the metabolism of BPAF in vivo and the estrogenic activity of its metabolites remain unknown. In the present study, we identified four metabolites including BPAF diglucuronide, BPAF glucuronide (BPAF-G), BPAF glucuronide dehydrated and BPAF sulfate in the urine of Sprague-Dawley (SD) rats. BPAF-G was further characterized by nuclear magnetic resonance (NMR). After treatment with a single dose of BPAF, BPAF was metabolized rapidly to BPAF-G, as detected in the plasma of SD rats. Biotransformation of BPAF to BPAF-G was confirmed with human liver microsomes (HLM), and Vmax of glucuronidation for HLM was 11.6 nmol/min/mg. We also found that BPAF glucuronidation could be mediated through several human recombinant UDP-glucuronosyltransferases (UGTs) including UGT1A1, UGT1A3, UGT1A8, UGT1A9, UGT2B4, UGT2B7, UGT2B15 and UGT2B17, among which UGT2B7 showed the highest efficiency of glucuronidation. To explain the biological function of BPAF biotransformation, the estrogenic activities of BPAF and BPAF-G were evaluated in ER-positive breast cancer T47D and MCF7 cells. BPAF significantly stimulates ER-regulated gene expression and cell proliferation at the dose of 100 nM and 1 ?M in breast cancer cells. However, BPAF-G did not show any induction of estrogenic activity at the same dosages, implying that formation of BPAF-G is a potential host defense mechanism against BPAF. Based on our study, biotransformation of BPAF to BPAF-G can eliminate BPAF-induced estrogenic activity, which is therefore considered as reducing the potential threat to human beings. PMID:24349450

Li, Ming; Yang, Yunjia; Yang, Yi; Yin, Jie; Zhang, Jing; Feng, Yixing; Shao, Bing

2013-01-01

229

Role of Glucuronidation for Hepatic Detoxification and Urinary Elimination of Toxic Bile Acids during Biliary Obstruction  

PubMed Central

Biliary obstruction, a severe cholestatic condition, results in a huge accumulation of toxic bile acids (BA) in the liver. Glucuronidation, a conjugation reaction, is thought to protect the liver by both reducing hepatic BA toxicity and increasing their urinary elimination. The present study evaluates the contribution of each process in the overall BA detoxification by glucuronidation. Glucuronide (G), glycine, taurine conjugates, and unconjugated BAs were quantified in pre- and post-biliary stenting urine samples from 12 patients with biliary obstruction, using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The same LC-MS/MS procedure was used to quantify intra- and extracellular BA-G in Hepatoma HepG2 cells. Bile acid-induced toxicity in HepG2 cells was evaluated using MTS reduction, caspase-3 and flow cytometry assays. When compared to post-treatment samples, pre-stenting urines were enriched in glucuronide-, taurine- and glycine-conjugated BAs. Biliary stenting increased the relative BA-G abundance in the urinary BA pool, and reduced the proportion of taurine- and glycine-conjugates. Lithocholic, deoxycholic and chenodeoxycholic acids were the most cytotoxic and pro-apoptotic/necrotic BAs for HepG2 cells. Other species, such as the cholic, hyocholic and hyodeoxycholic acids were nontoxic. All BA-G assayed were less toxic and displayed lower pro-apoptotic/necrotic effects than their unconjugated precursors, even if they were able to penetrate into HepG2 cells. Under severe cholestatic conditions, urinary excretion favors the elimination of amidated BAs, while glucuronidation allows the conversion of cytotoxic BAs into nontoxic derivatives.

Perreault, Martin; Bialek, Andrzej; Trottier, Jocelyn; Verreault, Melanie; Caron, Patrick; Milkiewicz, Piotr; Barbier, Olivier

2013-01-01

230

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

231

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

232

Glucuronidation of 3'-azido-3'-deoxythymidine in human liver microsomes: enzyme inhibition by drugs and steroid hormones.  

PubMed

The molecular form of UDP-glucuronosyltransferase involved in the catalysis of 3'-azido-3'-deoxythymidine (AZT)-5'-O-glucuronide was characterized in human liver microsomes. The specific activity (1.3 nmol/min per mg protein) in transplantable liver was more than 2-times higher than in post-mortem fragments. Liver microsomes from patients suffering Crigler-Najjar syndrome, who are genetically deficient in bilirubin UDP-glucuronosyltransferase, could also glucuronidate AZT to a similar extent, thus indicating that this protein was not involved in that process. A genetically engineered V79 cell line stably expressing a cDNA which encodes a human isozyme active towards 1-naphthol was unable to glucuronidate AZT. Clinically used drugs, most of them being glucuronidated, were tested as potential inhibitors of the glucuronidation of AZT in human liver microsomes. The drugs chemically related to 2-phenylpropionic acid, naproxen and flurbiprofen, and the steroid compounds testosterone, estrone and ethynylestradiol strongly inhibited AZT glucuronidation. Codeine and morphine also decreased the reaction rate although to a lower extent. Except estrone which elicited a partial competitive inhibition, ethynylestradiol, flurbiprofen naproxen and testosterone could competitively inhibit AZT glucuronidation with an apparent Ki of 38, 50, 172 and 250 microM, respectively. The results suggest that these drugs were substrates of the same isozyme(s) involved in AZT glucuronidation. Probenecid was a weak inhibitor of the reaction (Ki 900 microM), only when non-disrupted microsomes were used. This drug may compete with the anion carrier system involved in the microsomal uptake of UDP-glucuronic acid. PMID:1610916

Herber, R; Magdalou, J; Haumont, M; Bidault, R; van Es, H; Siest, G

1992-06-01

233

Methyl radical addition to methyl ethyl ketone  

Microsoft Academic Search

From relative rates of acetone formation in the azomethane sensitized decomposition of methyl ethyl ketone at 290 °C, log10(k\\/cm3mol?1s?1)=5.3±0.4 for the methyl radical addition to methyl ethyl ketone has been determined.

H. Knoll

1981-01-01

234

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

235

Mechanism of Peroxisome Proliferator-Activated Receptor Gamma (PPAR?) Transactivation by Hesperetin Glucuronides Is Distinct from That by a Thiazolidine-2,4-dione Agent.  

PubMed

Hesperidin, a flavanone glycoside present abundantly in citrus fruits, is predominantly metabolized to hesperetin-7-O-?-D-glucuronide (H7-OG) and hesperetin-3'-O-?-D-glucuronide (H3'-OG), which exhibit partial agonistic activity towards peroxisome proliferator-activated receptor gamma (PPAR?). Here, in order to understand the mechanism(s) of action of PPAR? transactivation elicited by hesperetin glucuronides, we compared the transactivation activities of PPAR? (ligand-binding domain (LBD)) mutants by hesperetin glucuronides and troglitazone, a thiazolidine-2,4-dione class PPAR? full agonist. The assay results indicated that the mechanisms of activation of PPAR? by hesperetin glucuronides and by troglitazone are distinct, probably due to a difference in the binding sites of these compounds on the PPAR? LBD. Flavanone-class PPAR? partial agonists, luteolin and hesperetin glucuronides, showed similar activation profiles of the PPAR? LBD mutants, even though they have different side chain functionalities. PMID:24789933

Gamo, Kanae; Shiraki, Takuma; Matsuura, Nobuyasu; Miyachi, Hiroyuki

2014-01-01

236

Biotransformation of diflunisal and renal excretion of its glucuronides in renal insufficiency  

PubMed Central

1 A single oral dose of 500 mg diflunisal was administered to control subjects and patients with varying degrees of renal insufficiency to estimate the disposition kinetics of this drug. 2 Diflunisal and the sum of its ester and ether glucuronides conjugates were measured fluorimetrically. 3 In normals terminal plasma half-lives (T½?) of diflunisal and its glucuronides were very similar: 10.8 h and 11.8 h respectively. The finding that plasma half-life was shortened with declining diflunisal plasma levels suggests capacity-limited elimination. 4 In subjects with normal renal function 78.6 ± 2.7% of the administered dose was recovered in 72 h urine, mainly as the glucuronide conjugates. 5 With increasing degree of renal function impairment T½? of diflunisal was progressively prolonged up to ten times normal probably due to slowed biotransformation. This was associated with increasing retention of the conjugated metabolites in plasma due to marked reduction of the urinary excretion of the glucuronide conjugates. 6 The apparent volume of distribution of diflunisal was very small in normals (7.3 ± 0.4 l) and was significantly increased in patients with renal insufficiency (up to 16.2 ± 2.2 l). 7 Diflunisal elimination studies performed during haemodialysis did not reveal any significant change in diflunisal plasma half-time. In vivo ultrafiltration studies during haemodialysis have shown that diflunisal is 98-99% plasma protein bound in uraemic patients. 8 The present study indicates that although diflunisal is primarily eliminated by biotransformation, T½? is prolonged in renal insufficiency and dose adjustment will accordingly be required in patients with renal function impairment.

Verbeeck, R.; Tjandramaga, T. B.; Mullie, A.; Verbesselt, R.; Verberckmoes, R.; De Schepper, P. J.

1979-01-01

237

Sensitive determination of estriol-16-glucuronide using surface plasmon resonance sensing  

Microsoft Academic Search

For the quantitative evaluation of low levels of an estriol metabolite of estriol (estriol-16-glucuronide (E3-16G)) in liquid media, we developed a simple and highly sensitive immunoassay using a surface plasmon resonance (SPR) biosensor which did not require any time-consuming sample pretreatment steps. E3-16G was conjugated to ovalbumin (OVA) through an oligoethylene glycol (OEG) linker to form protein conjugates (E3-16G-OEG-OVA), which

Xiuqian Jiang; Mark Waterland; Len Blackwell; Yinqiu Wu; Krishanthi P. Jayasundera; Ashton Partridge

2008-01-01

238

Metabolic comparison of radiolabeled bleomycin and bleomycin-glucuronide labeled with 99mTc.  

PubMed

The metabolic comparison of bleomycin (BLM) and bleomycin-glucuronide (BLMG) radiolabeled with (99m)Tc ((99m)Tc-BLM and (99m)Tc-BLMG, respectively) has been investigated in this study. Quality control procedures were carried out using thin-layer radiochromatography and high-performance liquid chromatography. To compare the metabolic behavior of BLM and its glucuronide conjugate radiolabeled with (99m)Tc, scintigraphic, and biodistributional techniques were applied using male New Zealand rabbits and Albino Wistar rats. The results obtained have shown that these compounds were successfully radiolabeled with a labeling yield of about 100%. Maximum uptakes of (99m)Tc-BLM and (99m)Tc-BLMG metabolized as N-glucuronide were observed within 2 hours in the liver, the bladder, and the spinal cord for (99m)Tc-BLM and the lung, the liver, the kidney, the large intestine, and the spinal cord for (99m)Tc-BLMG, respectively. Scintigraphy and biodistributional studies performed on the experimental animals have shown that radiopharmaceutical potentials of these compounds are completely different. At the same time, uptake of the (99m)Tc-BLMG was found to be better than that of (99m)Tc-BLM. PMID:21950554

Koçan, Feray; Avc?ba??, Ugur; Unak, Perihan; Müftüler, Fazilet Zümrüt Biber; Içhedef, Cigdem A; Demiro?lu, Hasan; Gümü?er, Fikriye G

2011-10-01

239

?-Glucuronidase activity and mitochondrial dysfunction: the sites where flavonoid glucuronides act as anti-inflammatory agents  

PubMed Central

Epidemiological and experimental studies suggest that the consumption of flavonoid-rich diets decreases the risk of various chronic diseases such as cardiovascular diseases. Although studies on the bioavailability of flavonoids have been well-characterized, the tissue and cellular localizations underlying their biological mechanisms are largely unknown. The development and application of novel monoclonal antibodies revealed that macrophages could be the major target of dietary flavonoids in vivo. Using macrophage-like cell lines in vitro, we examined the molecular basis of the interaction between the macrophages and flavonoids, especially the glucuronide metabolites. We have found that extracellular ?-glucuronidase secreted from macrophages is essential for the bioactivation of the glucuronide conjugates into the aglycone, and that the enzymatic activity, which requires an acidic pH, is promoted by the increased secretion of lactate in response to the mitochondrial dysfunction. This review describes our recent findings indicating the molecular mechanisms responsible for the anti-inflammatory activity of dietary flavonoids within the inflammation sites. We propose that the extracellular activity of ?-glucuronidase associated with the status of the mitochondrial function in the target cells might be important biomarkers for the specific sites where the glucuronides of dietary flavonoids can act as anti-atherosclerotic and anti-inflammatory agents in vivo.

Kawai, Yoshichika

2014-01-01

240

Rapid and sensitive determination of propofol glucuronide in hair by liquid chromatography and tandem mass spectrometry.  

PubMed

A fast, sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the detection and quantitation of propofol glucuronide in human hair has been developed and validated. Propofol glucuronide was extracted from 10mg of hair using a simple methanol extraction method, with recovery greater than 91% at 3 quality control samples (15, 100, 4000 pg/mg). A reversed phase column (C8) was used to analyze and the mobile phase was composed of ammonium formate and acetonitrile gradient at a flow rate of 0.2 mL/min. The lower limit of quantitation (LLOQ) was 5 pg/mg and the assay was linear to 5000 pg/mg. The intra- and inter-day precision (% CV, coefficient of variation) ranged from 1.26 to 4.50% while the accuracy (% RE, relative error) were -4.24 to 4.4%. The matrix effects were monitored at 3 different concentrations and the %CV of the results for these concentrations was less than 10.6%. Propofol glucuronide was stable during processing and analysis in human hair. The procedure was validated and applied to the analysis of hair samples in human subjects previously administered in propofol. PMID:23872469

Kim, Hee Seung; Cheong, Jae Chul; Lee, Jae Il; In, Moon Kyo

2013-11-01

241

?-Glucuronidase activity and mitochondrial dysfunction: the sites where flavonoid glucuronides act as anti-inflammatory agents.  

PubMed

Epidemiological and experimental studies suggest that the consumption of flavonoid-rich diets decreases the risk of various chronic diseases such as cardiovascular diseases. Although studies on the bioavailability of flavonoids have been well-characterized, the tissue and cellular localizations underlying their biological mechanisms are largely unknown. The development and application of novel monoclonal antibodies revealed that macrophages could be the major target of dietary flavonoids in vivo. Using macrophage-like cell lines in vitro, we examined the molecular basis of the interaction between the macrophages and flavonoids, especially the glucuronide metabolites. We have found that extracellular ?-glucuronidase secreted from macrophages is essential for the bioactivation of the glucuronide conjugates into the aglycone, and that the enzymatic activity, which requires an acidic pH, is promoted by the increased secretion of lactate in response to the mitochondrial dysfunction. This review describes our recent findings indicating the molecular mechanisms responsible for the anti-inflammatory activity of dietary flavonoids within the inflammation sites. We propose that the extracellular activity of ?-glucuronidase associated with the status of the mitochondrial function in the target cells might be important biomarkers for the specific sites where the glucuronides of dietary flavonoids can act as anti-atherosclerotic and anti-inflammatory agents in vivo. PMID:24895476

Kawai, Yoshichika

2014-05-01

242

Preparation and separation of the glucuronide and sulfate conjugates of thyroxine and triiodothyronine  

SciTech Connect

An enzymatic method for synthesis of labelled thyroxine glucuronide (T4G) and triiodothyronine glucuronide (T3G) from labelled thyroxine (T4) and triiodothyronine (T3) is presented. The synthetic glucuronides are completely digested by beta-glucuronidase, with recovery of the parent T4 or T3. They have distinctive elution patterns on HPLC and on Sephadex G25 chromatography, and can be clearly separated from T4 and T3 as well as from synthetic T4 sulfate (T4S) and T3 sulfate (T3S). On LH 20 chromatography, elution of T4G and T3G is intermediate between that of T4 and T3 and that of T4S and T3S. T3G can be well separated from other thyronines by HPLC alone, but T4G coelutes with rT3 on HPLC; these are then separated by adding a Sephadex G25 chromatography step. Biosynthetic /sup 131/I-T3G and /sup 125/I-T4G from the bile of a cat given /sup 131/I-T3 and /sup 125/I-T4 had similar HPLC chromatographic patterns to those of synthetic T3G and T4G. That the identified peaks from analysis of the bile were indeed T3G and T4G was confirmed by recovery of the parent T3 and T4 after beta-glucuronidase digestion.

Hays, M.T.; Hsu, L.

1987-01-01

243

The glucuronidation of mycophenolic acid by human liver, kidney and jejunum microsomes  

PubMed Central

Aims To estimate the relative contribution of liver, kidney and jejunum to MPA elimination via glucuronidation from in vitro kinetic data. Methods The kinetics of MPA glucuronidation by human liver, kidney and jejunum microsomes were characterized. Mycophenolic acid glucuronide (MPAG) concentrations in microsomal incubations were determined using a specific h.p.l.c. procedure. Non-specific microsomal binding of MPA was excluded using an equilibrium dialysis approach. Results Microsomes from all three tissues catalysed the conversion of MPA to MPAG. Mean microsomal intrinsic clearances for MPAG formation by liver, kidney and jejunum microsomes were 46.6, 73.5 and 24.5 µl (min mg)?1, respectively. When extrapolated to the whole organ, however, hepatic intrinsic clearance was 21- and 38-fold higher than the respective intrinsic clearances for kidney and small intestine. Conclusions The data suggest that the liver is the organ primarily responsible for the systemic clearance of MPA, with little contribution from the kidney, and that the small intestine would be expected to contribute to first-pass extraction to a minor extent only.

Bowalgaha, Kushari; Miners, John O

2001-01-01

244

Mutagenic Action of Ethyl Methanesulfonate in Maize.  

PubMed

Pollen of corn plants carrying three closely linked genes (alpha beta Sh(2)) on chromosome 3 were treated by ethyl methanesulfonate in order to determine the nature of genetic changes produced. In this genetic material the loss of the beta gene alone represents a discrete genetic change, possibly a point mutation, while the loss of two or more markers represents chromosome aberrations. Ethyl methanesulfonate, x-rays, and ultraviolet light all induced numerous chromosome aberrations, but only ultraviolet light and probably ethyl methanesulfonate induced discrete genetic changes. PMID:17757068

Neuffer, M G; Ficsor, G

1963-03-29

245

Regiospecificity of Human UDP-glucuronosyltransferase Isoforms in Chalcone and Flavanone Glucuronidation Determined by Metal Complexation and Tandem Mass Spectrometry  

PubMed Central

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 nine human UDP-glucuronosyltransferase (UGT) 1A enzymes was evaluated. A post-column 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.

Niemeyer, Emily D.; Brodbelt, Jennifer S.

2013-01-01

246

21 CFR 172.868 - Ethyl cellulose.  

Code of Federal Regulations, 2013 CFR

...DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Multipurpose Additives § 172.868 Ethyl cellulose. The...

2013-04-01

247

HEALTH EFFECTS ASSESSMENT FOR ETHYL CHLORIDE  

EPA Science Inventory

The report summarizes and evaluates information relevant to a preliminary interim assessment of adverse health effects associated with ethyl chloride. All estimates of acceptable intakes and carcinogenic potency presented in this document should be considered as preliminary and r...

248

Which hydroxy? Evidence for species differences in the regioselectivity of glucuronidation in rat, dog, and human in vitro systems and dog in vivo.  

PubMed

The glucuronidation of (1S,2R,3R,5R)-3-(hydroxymethyl)-5-[7-{[(1R,2S)-2-phenylcyclopropyl]amino}-5-(propylthio)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-3-yl]cyclopentane-1,2-diol (AZ11939714) was studied in UDP-glucuronic acid (UDPGA)-supplemented hepatic microsomes from rat, dog, and human liver. The major biliary metabolite of this compound after intraduodenal administration to a beagle dog was also studied. The techniques of HPLC, HPLC-MS and HPLC-NMR were used to characterize the glucuronides. An analysis of the proton NMR chemical shift differences between parent and metabolites was sufficient to deduce the sites of glucuronidation, although these were confirmed by 2D ROESY experiments. In dog microsomes, AZ11939714 was O-glucuronidated exclusively at the 1-position of the cyclopentanediol. This glucuronide was also the major metabolite in dog bile. In human microsomes, AZ11939714 was O-glucuronidated almost exclusively at the 3-hydroxymethyl position. Rat microsomes produced a mixture of glucuronides at the 2-position of the cyclopentanediol (major) and at the 3-hydroxymethyl position (minor). A clear qualitative species difference in the glucuronidation of AZ11939714 has been demonstrated in vitro. This may have implications for the choice of laboratory species to study the pharmacokinetics and safety of this compound. PMID:16763016

Martin, Iain J; Lewis, Richard J; Bernstein, Michael A; Beattie, Iain G; Martin, Craig A; Riley, Robert J; Springthorpe, Brian

2006-09-01

249

Hepatic clearance of reactive glucuronide metabolites of diclofenac in the mouse is dependent on multiple ATP-binding cassette efflux transporters.  

PubMed

Diclofenac is an important analgesic and anti-inflammatory drug that is widely used for the treatment of postoperative pain, rheumatoid arthritis, and chronic pain associated with cancer. Diclofenac is extensively metabolized in the liver, and the main metabolites are hydroxylated and/or glucuronidated conjugates. We show here that loss of multidrug resistance protein 2 (MRP2/ABCC2) and breast cancer resistance protein (BCRP/ABCG2) in mice results in highly increased plasma levels of diclofenac acyl glucuronide, after both oral and intravenous administration. The absence of Mrp2 and Bcrp1, localized at the canalicular membrane of hepatocytes, leads to impaired biliary excretion of acyl glucuronides and consequently to elevated liver and plasma levels. Mrp2 also mediates the biliary excretion of two hydroxylated diclofenac metabolites, 4'-hydroxydiclofenac and 5-hydroxydiclofenac. We further show that the sinusoidal efflux of diclofenac acyl glucuronide, from liver to blood, is largely dependent on multidrug resistance protein 3 (MRP3/ABCC3). Diclofenac acyl glucuronides are chemically instable and reactive, and in patients, these metabolites are associated with rare but serious idiosyncratic liver toxicity. This might explain why Mrp2/Mrp3/Bcrp1(-/-) mice, which have markedly elevated levels of diclofenac acyl glucuronides in their liver, display acute, albeit very mild, hepatotoxicity. We believe that the handling of diclofenac acyl glucuronides by ATP binding cassette transporters may be representative for the handling of acyl glucuronide metabolites of many other clinically relevant drugs. PMID:20086033

Lagas, Jurjen S; Sparidans, Rolf W; Wagenaar, Els; Beijnen, Jos H; Schinkel, Alfred H

2010-04-01

250

Reduced electron thermal transport in low collisionality H-mode plasmas in DIII-D and the importance of TEM/ETG-scale turbulence  

NASA Astrophysics Data System (ADS)

The first systematic investigation of core electron thermal transport and the role of local ion temperature gradient/trapped electron mode/electron temperature gradient (ITG/TEM/ETG)-scale core turbulence is performed in high temperature, low collisionality H-mode plasmas in the DIII-D tokamak. Wavenumber spectra of L-mode and H-mode density turbulence are measured by Doppler backscattering. H-mode wavenumber spectra are directly contrasted for the first time with nonlinear gyrokinetic simulation results. Core ITG/TEM-scale turbulence is substantially reduced/suppressed by E × B shear promptly after the L-H transition, resulting in reduced electron thermal transport across the entire minor radius. For small k??s, both experiment and nonlinear gyrokinetic simulations using the GYRO code show density fluctuation levels increasing with k??s in H-mode (r/a = 0.6), in contrast to ITG/TEM-dominated L-mode plasmas. GYRO simulations also indicate that a significant portion of the remaining H-mode electron heat flux results directly from residual intermediate/short-scale TEM/ETG turbulence. Electron transport at substantially increased electron-to-ion temperature ratio (Te/Ti >= 1, r/a <= 0.35) has been investigated in ECH-assisted, quiescent H-mode plasmas. A synergistic increase in core electron and ion thermal diffusivity (normalized to the gyro-Bohm diffusivity) is found with applied ECH. From linear stability analysis, the TEM mode is expected to become the dominant linear instability with ECH due to increased electron-to-ion temperature ratio and a reduction in the ion temperature gradient. This is consistent with increased electron temperature fluctuations and core electron thermal diffusivity observed experimentally. The reduced ion temperature gradient likely results from a reduction in the ITG critical gradient due to increased Te/Ti and reduced E × B shear. These studies are performed at collisonality ( \

Schmitz, L.; Holland, C.; Rhodes, T. L.; Wang, G.; Zeng, L.; White, A. E.; Hillesheim, J. C.; Peebles, W. A.; Smith, S. P.; Prater, R.; McKee, G. R.; Yan, Z.; Solomon, W. M.; Burrell, K. H.; Holcomb, C. T.; Doyle, E. J.; DeBoo, J. C.; Austin, M. E.; deGrassie, J. S.; Petty, C. C.

2012-02-01

251

Intestinal glucuronidation protects against chemotherapy-induced toxicity by irinotecan (CPT-11).  

PubMed

Camptothecin (CPT)-11 (irinotecan) has been used widely for cancer treatment, particularly metastatic colorectal cancer. However, up to 40% of treated patients suffer from severe late diarrhea, which prevents CPT-11 dose intensification and efficacy. CPT-11 is a prodrug that is hydrolyzed by hepatic and intestinal carboxylesterase to form SN-38, which in turn is detoxified primarily through UDP-glucuronosyltransferase 1A1 (UGT1A1)-catalyzed glucuronidation. To better understand the mechanism associated with toxicity, we generated tissue-specific Ugt1 locus conditional knockout mouse models and examined the role of glucuronidation in protecting against irinotecan-induced toxicity. We targeted the deletion of the Ugt1 locus and the Ugt1a1 gene specifically in the liver (Ugt1(?Hep)) and the intestine (Ugt1(?GI)). Control (Ugt1(F/F)), Ugt1(?Hep), and Ugt1(?GI) adult male mice were treated with different concentrations of CPT-11 daily for four consecutive days. Toxicities were evaluated with regard to tissue glucuronidation potential. CPT-11-treated Ugt1(?Hep) mice showed a similar lethality rate to the CPT-11-treated Ugt1(F/F) mice. However, Ugt1(?GI) mice were highly susceptible to CPT-11-induced diarrhea, developing severe and lethal mucositis at much lower CPT-11 doses, a result of the proliferative cell loss and inflammation in the intestinal tract. Comparative expression levels of UGT1A1 in intestinal tumors and normal surrounding tissue are dramatically different, providing for the opportunity to improve therapy by differential gene regulation. Intestinal expression of the UGT1A proteins is critical toward the detoxification of SN-38, whereas induction of the UGT1A1 gene may serve to limit toxicity and improve the efficacy associated with CPT-11 treatment. PMID:24191041

Chen, Shujuan; Yueh, Mei-Fei; Bigo, Cyril; Barbier, Olivier; Wang, Kepeng; Karin, Michael; Nguyen, Nghia; Tukey, Robert H

2013-11-19

252

Intestinal glucuronidation protects against chemotherapy-induced toxicity by irinotecan (CPT-11)  

PubMed Central

Camptothecin (CPT)-11 (irinotecan) has been used widely for cancer treatment, particularly metastatic colorectal cancer. However, up to 40% of treated patients suffer from severe late diarrhea, which prevents CPT-11 dose intensification and efficacy. CPT-11 is a prodrug that is hydrolyzed by hepatic and intestinal carboxylesterase to form SN-38, which in turn is detoxified primarily through UDP-glucuronosyltransferase 1A1 (UGT1A1)-catalyzed glucuronidation. To better understand the mechanism associated with toxicity, we generated tissue-specific Ugt1 locus conditional knockout mouse models and examined the role of glucuronidation in protecting against irinotecan-induced toxicity. We targeted the deletion of the Ugt1 locus and the Ugt1a1 gene specifically in the liver (Ugt1?Hep) and the intestine (Ugt1?GI). Control (Ugt1F/F), Ugt1?Hep, and Ugt1?GI adult male mice were treated with different concentrations of CPT-11 daily for four consecutive days. Toxicities were evaluated with regard to tissue glucuronidation potential. CPT-11–treated Ugt1?Hep mice showed a similar lethality rate to the CPT-11–treated Ugt1F/F mice. However, Ugt1?GI mice were highly susceptible to CPT-11–induced diarrhea, developing severe and lethal mucositis at much lower CPT-11 doses, a result of the proliferative cell loss and inflammation in the intestinal tract. Comparative expression levels of UGT1A1 in intestinal tumors and normal surrounding tissue are dramatically different, providing for the opportunity to improve therapy by differential gene regulation. Intestinal expression of the UGT1A proteins is critical toward the detoxification of SN-38, whereas induction of the UGT1A1 gene may serve to limit toxicity and improve the efficacy associated with CPT-11 treatment.

Chen, Shujuan; Yueh, Mei-Fei; Bigo, Cyril; Barbier, Olivier; Wang, Kepeng; Karin, Michael; Nguyen, Nghia; Tukey, Robert H.

2013-01-01

253

Rapid stimulation of free glucuronate formation by non-glucuronidable xenobiotics in isolated rat hepatocytes.  

PubMed

Vitamin C synthesis in rat liver is enhanced by several xenobiotics, including aminopyrine and chloretone. The effect of these agents has been linked to induction of enzymes potentially involved in the formation of glucuronate, a precursor of vitamin C. Using isolated rat hepatocytes as a model, we show that a series of agents (aminopyrine, antipyrine, chloretone, clotrimazole, metyrapone, proadifen, and barbital) induced in a few minutes an up to 15-fold increase in the formation of glucuronate, which was best observed in the presence of sorbinil, an inhibitor of glucuronate reductase. They also caused an approximately 2-fold decrease in the concentration of UDP-glucuronate but little if any change in the concentration of UDP-glucose. Depletion of UDP-glucuronate with resorcinol or d-galactosamine markedly decreased the formation of glucuronate both in the presence and in the absence of aminopyrine, confirming the precursor-product relationship between UDP-glucuronate and free glucuronate. Most of the agents did not induce the formation of detectable amounts of glucuronides, indicating that the formation of glucuronate is not due to a glucuronidation-deglucuronidation cycle. With the exception of barbital (which inhibits glucuronate reductase), all of the above mentioned agents also caused an increase in the concentration of ascorbic acid. They had little effect on glutathione concentration, and their effect on glucuronate and vitamin C formation was not mimicked by glutathione-depleting agents such as diamide and buthionine sulfoximine. It is concluded that the stimulation of vitamin C synthesis exerted by some xenobiotics is mediated through a rapid increase in the conversion of UDP-glucuronate to glucuronate, which does not apparently involve a glucuronidation-deglucuronidation cycle. PMID:12865420

Linster, Carole L; Van Schaftingen, Emile

2003-09-19

254

Enzyme-assisted synthesis of the glucuronide conjugate of psilocin, an hallucinogenic component of magic mushrooms.  

PubMed

An enzyme-assisted synthesis of psilocin glucuronide (PCG), a metabolite excreted in the urine of magic mushroom (MM) users, is described. In the presence of Aroclor 1254 pretreated rat liver microsomes, psilocin and the cofactor UDPGA were incubated for 20 h. Purification by HPLC gave PCG in 19% yield (3.6 mg). The compound structure was characterized by MS and NMR. The milligram amounts of PCG produced by this method will allow the direct identification and quantification of PCG in the urine of MM users. PMID:21960543

Shoda, Takuji; Fukuhara, Kiyoshi; Goda, Yukihiro; Okuda, Haruhiro

2011-09-01

255

Effect of chronic undernutrition on glucuronide and glutathione conjugation in rat liver.  

PubMed

Glucuronide and glutathione conjugation reactions were studied in rats with varying degrees of diet restriction over a period of 15 weeks. No significant change in the UDP glucuronyl transferase activity with para-nitrophenol and chloramphenicol was observed under both native state and stimulated conditions. On the other hand, there was a progressive decrease in the glutathione S transferase activity with bromosulphthalein and chlorodinitrobenzene. The decrease in the glutathione S transferase activity was more pronounced with chlorodinitrobenzene and was due more to the diminished apparent Vmax than to any change in the Km values. The results suggest that there might be an overall decrease in the conjugation reactions in food restriction. PMID:3928312

Rajpurohit, R; Krishnaswamy, K

1985-01-01

256

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

257

Regiospecificity and stereospecificity of human UDP-glucuronosyltransferases in the glucuronidation of estriol, 16-epiestriol, 17-epiestriol, and 13-epiestradiol.  

PubMed

The glucuronidation of estriol, 16-epiestriol, and 17-epiestriol by the human UDP-glucuronosyltransferases (UGTs) of subfamilies 1A, 2A, and 2B was examined. UGT1A10 is highly active in the conjugation of the 3-OH in all these estriols, whereas UGT2B7 is the most active UGT toward one of the ring D hydroxyls, the 16-OH in estriol and 16-epiestriol, but the 17-OH in 17-epiestriol. Kinetic analyses indicated that the 17-OH configuration plays a major role in the affinity of UGT2B7 for estrogens. The glucuronidation of the different estriols by the human liver and intestine microsomes reflects the activity of UGT1A10 and UGT2B7 in combination with the tissues' difference in UGT1A10 expression. The UGT1A10 mutant 1A10-F93G exhibited much higher V(max) values than UGT1A10 in estriol and 17-epiestriol glucuronidation, but a significantly lower value in 16-epiestriol glucuronidation. To this study on estriol glucuronidation we have added experiments with 13-epiestradiol, a synthetic estradiol in which the spatial arrangement of the methyl on C18 and the hydroxyl on C17 is significantly different than in other estrogens. In comparison with estradiol glucuronidation, the C13 configuration change decreases the turnover of UGTs that conjugate the 3-OH, but increases it in UGTs that primarily conjugate the 17-OH. Unexpectedly, UGT2B17 exhibited similar conjugation rates of both the 17-OH and 3-OH of 13-espiestradiol. The combined results reveal the strong preference of UGT1A10 for the 3-OH of physiologic estrogens and the equivalently strong preference of UGT2B7 and UGT2B17 for the hydroxyls on ring D of such steroid hormones. PMID:23288867

Sneitz, Nina; Vahermo, Mikko; Mosorin, Johanna; Laakkonen, Liisa; Poirier, Donald; Finel, Moshe

2013-03-01

258

Characterization of a rat liver glucuronosyltransferase that glucuronidates the selective D1 antagonist, SCH 23390, and other benzazepines.  

PubMed

SCH 23390 is a novel benzazepine that selectively blocks dopamine receptors of the D1 subtype. Glucuronidation of this selective D1 antagonist was studied in vitro using rat liver microsomes. Methods to separate SCH 23390 glucuronide from SCH 23390 were developed which utilized either HPLC techniques or solvent extraction of SCH 23390 with 3-heptanone. Formation of a SCH 23390 glucuronide was confirmed upon incubation of SCH 23390 and UDPGA with naive rat liver microsomes. Liver enzyme activity for SCH 23390 glucuronidation was also enhanced after addition of the detergents, Lubrol or Triton X-100, to the naive liver microsomes. Kinetic analyses indicated an apparent Vmax and Km for UDPGA as 120.9 pmol/mg protein/min and 0.63 mM, and an apparent Vmax and Km for SCH 23390 as 282.4 pmol/mg protein/min and 0.41 microM. Further characterization of the liver enzyme responsible for the glucuronidation of SCH 23390 revealed a stereoselective substrate preference similar to that seen with the D1 dopamine receptor. Substrate inhibition studies indicated that SCH 23390, haloperidol, apomorphine, and alpha-naphthol demonstrated the highest affinity for the glucuronosyltransferase enzyme. However, (-)-sulpiride, raclopride, and endogenous substrates such as dopamine, serotonin, epinephrine, and norepinephrine demonstrated low affinity for the liver enzyme. These studies describe a rat liver glucuronosyltransferase with a unique substrate specificity toward selected dopaminergic agents. Finally, induction profiles revealed that neither phenobarbital (100 mg/kg, ip, for 3 days), beta-naphthoflavone (100 mg/kg, ip, for 4 days), nor 3-methylcholanthrene (80 mg/kg, ip, for 4 days) enhanced liver glucuronosyltransferase activity for SCH 23390 glucuronidation. PMID:1687024

Tedford, C E; Ruperto, V B; Barnett, A

1991-01-01

259

2D QSAR Study for Gemfibrozil Glucuronide as the Mechanism-based Inhibitor of CYP2C8.  

PubMed

Mechanism-based inhibition of cytochrome P450 involves the bioactivation of the drug to a reactive metabolite, which leads to cytochrome inhibition via various mechanisms. This is generally seen in the Phase I of drug metabolism. However, gemfibrozil (hypolipidemic drug) leads to mechanism-based inhibition after generating glucuronide conjugate (gemfibrozil acyl-?-glucuronide) in the Phase II metabolism reaction. The mechanism involves the covalent binding of the benzyl radical (generated from the oxidation of aromatic methyl group in conjugate) to the heme of CYP2C8. This article deals with the development of a 2D QSAR model based on the inhibitory potential of gemfibrozil, its analogues and corresponding glucuronide conjugates in inhibiting the CYP2C8-catalysed amodiaquine N-deethylation. The 2D QSAR model was developed using multiple linear regression analysis in Accelrys Discovery Studio 2.5 and helps in identifying the descriptors, which are actually contributing to the inhibitory potency of the molecules studied. The built model was further validated using leave one out method. The best quantitative structure activity relationship model was selected having a correlation coefficient (r) of 0.814 and cross-validated correlation coefficient (q(2)) of 0.799. 2D QSAR revealed the importance of volume descriptor (Mor15v), shape descriptor (SP09) and 3D matrix-based descriptor (SpMax_RG) in defining the activity for this series of molecules. It was observed that volume and 3D matrix-based descriptors were crucial in imparting higher potency to gemfibrozil glucuronide conjugate, as compared with other molecules. The results obtained from the present study may be useful in predicting the inhibitory potential (IC50 for CYP2C8 inhibition) of the glucuronide conjugates of new molecules and compare with the standard gemfibrozil acyl-?-glucuronide (in terms of pIC50 values) in early stages of drug discovery and development. PMID:24591743

Taxak, N; Bharatam, P V

2013-11-01

260

Overestimation of flavonoid aglycones as a result of the ex vivo deconjugation of glucuronides by the tissue ?-glucuronidase.  

PubMed

Flavonoid glucuronides are the main circulating metabolites of flavonoids in humans and animals. There has been a growing interest in the biological function of glucuronides. In order to differentiate biological activity and to assess efficacy it is essential to accurately determine the levels of flavonoid aglycone and metabolic conjugate in vivo. Many organs and body fluids of humans and animals exhibit ?-glucuronidase against flavonoid glucuronides. Studies have shown that ?-glucuronidase within the tissues hydrolyzes glucuronides to their aglycones during the tissue extraction, leading to artificially higher reported tissue levels of aglycone than actual in vivo concentrations. The aims of this study were to estimate the extent by which the aglycones were overestimated and to investigate the use of saccharo-1,4-lactone, a ?-glucuronidase inhibitor, to block the ex vivo hydrolysis of flavonoid glucuronides. Our data demonstrate that in mouse liver tissues and human tumor xenografts levels of quercetin and methylated quercetin aglycones could be over-estimated by 7-fold. The inhibition of deconjugation of quercetin and baicalein glucuronides by saccharo-1,4-lactone is dose-dependent. The amount of saccharo-1,4-lactone used to produce optimal inhibition of the enzyme activity is in the range of 15-24?mol per gram of liver tissue. The use of ?-glucuronidase inhibitor blocks the ex vivo deconjugation resulting in an accurate estimation of tissue levels of aglycone and conjugate. Our study described here can be extended to other animal models and human studies with different types of substrates of ?-glucuronidase. PMID:24176739

Lu, Qing-Yi; Zhang, Lifeng; Eibl, Guido; Go, Vay Liang W

2014-01-25

261

2D QSAR Study for Gemfibrozil Glucuronide as the Mechanism-based Inhibitor of CYP2C8  

PubMed Central

Mechanism-based inhibition of cytochrome P450 involves the bioactivation of the drug to a reactive metabolite, which leads to cytochrome inhibition via various mechanisms. This is generally seen in the Phase I of drug metabolism. However, gemfibrozil (hypolipidemic drug) leads to mechanism-based inhibition after generating glucuronide conjugate (gemfibrozil acyl-?-glucuronide) in the Phase II metabolism reaction. The mechanism involves the covalent binding of the benzyl radical (generated from the oxidation of aromatic methyl group in conjugate) to the heme of CYP2C8. This article deals with the development of a 2D QSAR model based on the inhibitory potential of gemfibrozil, its analogues and corresponding glucuronide conjugates in inhibiting the CYP2C8-catalysed amodiaquine N-deethylation. The 2D QSAR model was developed using multiple linear regression analysis in Accelrys Discovery Studio 2.5 and helps in identifying the descriptors, which are actually contributing to the inhibitory potency of the molecules studied. The built model was further validated using leave one out method. The best quantitative structure activity relationship model was selected having a correlation coefficient (r) of 0.814 and cross-validated correlation coefficient (q2) of 0.799. 2D QSAR revealed the importance of volume descriptor (Mor15v), shape descriptor (SP09) and 3D matrix-based descriptor (SpMax_RG) in defining the activity for this series of molecules. It was observed that volume and 3D matrix-based descriptors were crucial in imparting higher potency to gemfibrozil glucuronide conjugate, as compared with other molecules. The results obtained from the present study may be useful in predicting the inhibitory potential (IC50 for CYP2C8 inhibition) of the glucuronide conjugates of new molecules and compare with the standard gemfibrozil acyl-?-glucuronide (in terms of pIC50 values) in early stages of drug discovery and development.

Taxak, N.; Bharatam, P. V.

2013-01-01

262

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

Microsoft Academic Search

A fast method using liquid–liquid extraction and HPLC\\/tandem-mass spectrometry (LC\\/MS\\/MS) was developed for the simultaneous detection of 11-Nor-?9-tetrahydrocannabinol-9-carboxylic acid ?-glucuronide (THC-COOH-glucuronide) and 11-Nor-?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

Wolfgang Weinmann; Susanne Vogt; Rolf Goerke; Claudia Müller; Andreas Bromberger

2000-01-01

263

Revolving Door Action of BCRP Facilitates or Controls the Efflux of Flavone Glucuronides from UGT1A9-Overexpressing HeLa Cells  

PubMed Central

Cellular production of flavonoid glucuronides requires the action of both UDP-glucuronosyltransferases (UGT) and efflux transporters since glucuronides are too hydrophilic to diffuse across the cellular membrane. We determined the kinetics of efflux of 13 flavonoid glucuronides using the newly developed HeLa-UGT1A9 cells and correlated them with kinetic parameters derived using expressed UGT1A9. The results indicated that among the seven monohydroxyflavones (HFs), there was moderately good correlation (r2?0.65) between fraction metabolized (fmet) derived from HeLa-UGT1A9 cells and CLint derived from the UGT1A9-mediated metabolism. However, there was weak or no correlation between these two parameters for six dihyroxylflavones (DHFs). Furthermore, there was weak no correlation between various kinetic parameters (Km, Vmax or CLint) for the efflux and the metabolism regardless if we were using 7 HFs, 6 DHFs or a combination thereof. Instead, cellular excretion of many flavonoids glucuronides appears to be controlled by the efflux transporter, and poor affinity of glucuronide to the efflux transporter resulted in major intracellular accumulation of glucuronides to a level that is above the dosing concentration of its aglycone. Hence, the efflux transporters appear to act as the “Revolving Door” to control the cellular excretion of glucuronides. In conclusion, the determination of a flavonoid's susceptibility to glucuronidation must be based on both its susceptibility to glucuronidation by the enzyme and resulting glucuronide's affinity to the relevant efflux transporters, which act as the “Revolving Door(s)” to facilitate or control its removal from the cells.

Wei, Yingjie; Wu, Baojian; Jiang, Wen; Yin, Taijun; Jia, Xiaobin; Basu, Sumit; Yang, Guangyi; Hu, Ming

2013-01-01

264

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

265

Identification of a new metabolite of GHB: gamma-hydroxybutyric acid glucuronide.  

PubMed

Gamma-hydroxybutyric acid (GHB) is an important analyte in clinical and forensic toxicology with a narrow detection window of 3-6 h. In the search of improved detection methods, the existence in vivo of a glucuronated GHB metabolite (GHB-GLUC) was hypothesized. Chemically pure standards of GHB-GLUC and a deuterated analogue for chromatography were synthesized. Liquid chromatography and tandem mass spectrometry were used for targeted analysis in anonymous clinical urine samples (n = 50). GHB-GLUC was found in concentrations ranging from 0.11 to 5.0 µg/mL (mean: 1.3 ± 1.2 µg/mL). Thus far, this is the first report of a GHB glucuronide detected in biological samples. Given that glucuronides generally have longer half-life values than their corresponding free drugs, GHB-GLUC should theoretically be a biomarker of GHB intoxication. It is also proposed that the hitherto unexplained reports of elevated GHB concentrations in some biological samples, which has caused the setting of a relatively high cutoff value (10 µg/mL), represent total GHB measurements (sum of free GHB and actively chemically hydrolyzed GHB-GLUC). To address these challenges, the present study must be followed by comprehensive pharmacokinetic and stability studies after the controlled administration of GHB. PMID:23612681

Petersen, Ida Nymann; Tortzen, Christian; Kristensen, Jesper Langgaard; Pedersen, Daniel Sejer; Breindahl, Torben

2013-06-01

266

Regioselective Glucuronidation of Oxyresveratrol, a Natural Hydroxystilbene, by Human Liver and Intestinal Microsomes and Recombinant UGTs.  

PubMed

Oxyresveratrol (OXY) is a natural hydroxystilbene that shows similar bioactivity but better water solubility than resveratrol. This study aims to characterize its glucuronidation kinetics in human liver (HLMs) and intestinal (HIMs) microsomes and identify the main UDP-glucuronosyltransferase (UGT) isoforms involved. Three and four mono-glucuronides of OXY were generated in HIMs and HLMs, respectively, with oxyresveratrol-2-O-?-d-glucuronosyl (G4) as the major metabolite in both organs. The kinetics of G4 formation fit a sigmoidal model in HLMs and biphasic kinetics in HIMs. Multiple UGT isoforms catalyzed G4 formation with the highest activity observed with UGT1A9 followed by UGT1A1. G4 formation by both isoforms followed substrate inhibition kinetics. Propofol (UGT1A9 inhibitor) effectively blocked G4 generation in HLMs (IC50 63.7 ± 11.6 µM), whereas the UGT1A1 inhibitor bilirubin only produced partial inhibition in HLMs and HIMs. These findings shed light on the metabolic mechanism of OXY and arouse awareness of drug interactions. PMID:24256624

Hu, Nan; Mei, Mei; Ruan, Jianqing; Wu, Wenjin; Wang, Yitao; Yan, Ru

2014-06-25

267

Effects of menthol on tobacco smoke exposure, nicotine dependence, and NNAL glucuronidation  

PubMed Central

Menthol is a controversial cigarette additive because its’ physiological or pharmacologic effects may possibly increase the risk of cancer and its targeted market is the black community. In a community-based cross-sectional study of 525 black and white volunteers, we compared levels of urinary and plasma cotinine, plasma thiocyanate, urinary 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanol (NNAL) and its detoxified form NNAL-Gluc between menthol and nonmenthol smokers. In regression models that adjusted for daily cigarette intake, no significant differences were observed in the concentration of these biomarkers by menthol status in both races. There was no significant association between high Fagerstrom nicotine dependence scores and the use of menthol cigarettes (odds ratio [OR] = 1.1, 95% confidence intervals [CI] 0.6–2.0), but an increased risk was observed with smoking a cigarette soon (?30 minutes) after waking (OR = 2.1, 95% CI 1.0–3.8). The ratio of NNAL-Gluc to NNAL, a possible indicator of lung cancer risk, was significantly lower in menthol vs. nonmenthol smokers. The NNAL-Gluc/NNAL ratio was 34% lower in whites (P<0.01) and 22% lower in blacks. In subsequent human liver microsome studies, menthol inhibited the rate of both NNAL-O-glucuronidation and NNAL-N-glucuronidation. Collectively, these results show that menthol does not affect biological exposure to tobacco smoke constituents, but indicates that menthol might inhibit the detoxification of the potent lung carcinogen NNAL.

Muscat, Joshua E.; Chen, Gang; Knipe, Ashley; Stellman, Steven D.; Lazarus, Philip; Richie, John P.

2009-01-01

268

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  

Microsoft Academic Search

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?g\\/g) and its main metabolite norclomipramine (1.10?g\\/g) at concentrations explaining the fatal outcome. The presence of these xenobiotics in a 12-cm-long strand of hair (clomipramine, 7.60ng\\/mg in I segment; 4.19ng\\/mg in II segment; 1.86ng\\/mg in

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

2005-01-01

269

Discovery of dopamine glucuronide in rat and mouse brain microdialysis samples using liquid chromatography tandem mass spectrometry.  

PubMed

A liquid chromatographic-electrospray/tandem mass spectrometric (LC-ESI-MS/MS) method was developed for the analysis of dopamine and its phase I and phase II metabolites from brain microdialysis samples. The method provides for the first time the analysis of intact dopamine glucuronide and sulfate without hydrolysis. The paper describes also an enzymatic synthesis method using rat liver microsomes as biocatalysts and characterization of dopamine glucuronide as a reference compound. The method was validated for quantitative analysis by determining limits of detection and quantitation, linearity,repeatability, and specificity. Dopamine glucuronide was found for the first time in rat and mouse brain microdialysis samples. The concentrations of dopamine and its glucuronide in the microdialysates collected from the striatum of rat brains were approximately equal (2 nM).Dopamine sulfate was not detected in the microdialysates(limit of detection 0.8 nM). The main metabolites of dopamine were dihydroxyphenylacetic acid (DOPAC,1200 nM) and homovanillic acid (HVA, 700 nM). PMID:19125450

Uutela, Päivi; Karhu, Laura; Piepponen, Petteri; Käenmäki, Mikko; Ketola, Raimo A; Kostiainen, Risto

2009-01-01

270

Prediction of urinary sulphate and glucuronide conjugate excretion for substituted phenols in the rat using quantitative structure-metabolism relationships.  

PubMed

1. The quantitative urinary excretion of the sulphate and glucuronide metabolites of 15 substituted phenols dosed to rat has been determined using high resolution 19F-nmr spectroscopy. 2. The urinary metabolic fate of each of the compounds was related to a series of calculated physicochemical properties for each compound to produce quantitative structure-metabolism relationships (QSMRs). Using these calculated molecular properties it was possible to predict the urinary recovery of xenobiotic material as a percentage of the administered dose, to classify the compounds according to their 'dominant' metabolite pattern and to predict quantitatively the proportions of glucuronide and sulphate conjugates in the urine by the use of multiple linear regression. 3. The quantitative predictions were tested by cross-validation and good prediction of total xenobiotic urinary recovery as a percentage of the administered dose was achieved based on an equation involving the electrophilic superdelocalizability at C4 (para to the hydroxyl function), the smallest principal ellipsoid axis dimension and the heat of formation. The largest moment of inertia and the electrophilic superdelocalizability at C3 were found to be the most significant factors for the prediction of the percentage glucuronide in the urine, and the urinary excretion of sulphate conjugates as a percentage of total urinary recovery was negatively correlated with the glucuronide excretion as little parent compound was excreted. PMID:8719903

Holmes, E; Sweatman, B C; Bollard, M E; Blackledge, C A; Beddell, C R; Wilson, I D; Lindon, J C; Nicholson, J K

1995-12-01

271

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...

272

Identification of Two Glucuronide Metabolites of Doxylamine via Thermospray/Mass Spectrometry and Thermospray/Mass Spectrometry/Mass Spectrometry.  

National Technical Information Service (NTIS)

Analysis of a high-pressure liquid chromatography fraction containing two urinary glucuronide metabolites of doxylamine by thermospray mass spectrometry (TSP/MS) provided (MH)+ ions for each metabolite. TSP/MS/MS of the (MH)+ ions provided a fragment ion ...

W. A. Korfmacher C. L. Holder L. D. Betowski R. K. Mitchum

1987-01-01

273

RELATIONSHIP BETWEEN HEPATIC MICROSOMAL THYROXINE GLUCURONIDATION AND TOTAL SERUM THYROXINE CONCENTRATIONS IN RATS TREATED WITH PCDDS, PCDFS AND PCBS  

EPA Science Inventory

RELATIONSHIP BETWEEN HEPATIC MICROSOMAL THYROXINE GLUCURONIDATION AND TOTAL SERUM THYROXINE CONCENTRATIONS IN RATS TREATED WITH PCDDs, PCDFs AND PCBs. D G Ross, K M Crofton, M J DeVito, NHEERL, ORD, USEPA, RTP, NC. Many PHAHs decrease thyroxine (T4), possibly due to inducti...

274

Pharmacokinetics of the glucuronide and sulfate conjugates of genistein and daidzein in men and women after consumption of a  

Microsoft Academic Search

Background: The soy isoflavones genistein and daidzein are found in blood and tissues as aglycones, glucuronides, and sul- fates. Isoflavone conjugates may serve as sources of aglycones at specific target tissues and may have bioactivity. Yet, very little is known about the plasma pharmacokinetics of isoflavone conju- gates after soy ingestion. Objective: The objective of this study was to determine

Susan R Shelnutt; Carolyn O Cimino; Patricia A Wiggins; Martin JJ Ronis; Thomas M Badger

275

IDENTIFICATION OF TWO GLUCURONIDE METABOLITES OF DOXYLAMINE VIA THERMOSPRAY/MASS SPECTROMETRY AND THERMOSPRAY/MASS SPECTROMETRY/MASS SPECTROMETRY  

EPA Science Inventory

Analysis of a high-pressure liquid chromatography fraction containing two urinary glucuronide metabolites of doxylamine by thermospray mass spectrometry (TSP/MS) provided (MH)+ ions for each metabolite. TSP/MS/MS of the (MH)+ ions provided a fragment ion characteristic of these m...

276

Summary of Emissions Associated with Sources of Ethyl Chloride,  

National Technical Information Service (NTIS)

The potential ambient health impact of ethyl chloride emissions has been investigated. The document contains information on the sources of ethyl chloride emissions, estimates current emission levels, summarizes production trends and ambient monitoring res...

G. L. Hume

1988-01-01

277

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

278

Ethyl pyruvate improves survival in awake hemorrhage.  

PubMed

Classical experimental models of hemorrhage are characterized by the use of anesthetics that may interfere with the typical immune responses and pathology of hemorrhage/resuscitation. Thus, therapeutic strategies successful in anesthetized animals might not be beneficial in clinical trials. In this study, we analyzed whether ethyl pyruvate could provide therapeutic benefits during resuscitation in awake (unanesthetized) hemorrhage. Our results indicate that hemorrhage in unanesthetized animals required approximately 25% higher blood withdrawal than anesthetized animals to achieve the same targeted mean arterial blood pressure. Resuscitation with Hextend reestablished circulatory volume and improved survival during resuscitation of awake rodents. Yet, over 75% of the animals resuscitated with Hextend died within the first hours after hemorrhage. Resuscitation with Hextend containing 50 mM ethyl pyruvate protected over 87% of the animals. This survival benefit did not correlate with significant changes in the metabolic markers but with an anti-inflammatory potential during resuscitation. Unlike classical hemorrhage in anesthetized animals, ethyl pyruvate reestablished mean arterial blood pressure significantly earlier than Hextend in unanesthetized rodents. Unanesthetized animals showed twofold higher serum tumor necrosis factor (TNF)-alpha than anesthetized animals subjected to the same blood pressure. This process was not due to the response of a single organ, but affected all the analyzed organs including the lung, heart, spleen, and liver. Although resuscitation with Hextend failed to attenuate systemic TNF-alpha levels, it inhibited TNF-alpha levels in the lung, heart, and liver but not in the spleen. Unlike Hextend, resuscitation with ethyl pyruvate prevented high serum TNF-alpha levels and blunted TNF-alpha responses in all the organs including the spleen. These studies indicate that the inflammatory responses in anesthetized animals differ from that in unanesthetized animals and that awake hemorrhage can provide advantages in the study of anti-inflammatory strategies during resuscitation. Ethyl pyruvate may attenuate systemic inflammatory responses during resuscitation and improve survival in experimental models of awake hemorrhage. PMID:19172241

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

2009-04-01

279

Ethyl pyruvate improves survival in awake hemorrhage  

PubMed Central

Classical experimental models of hemorrhage are characterized by the use of anesthetics that may interfere with the typical immune responses and pathology of hemorrhage/resuscitation. Thus, therapeutic strategies successful in anesthetized animals might not be beneficial in clinical trials. In this study, we analyzed whether ethyl pyruvate could provide therapeutic benefits during resuscitation in awake (unanesthetized) hemorrhage. Our results indicate that hemorrhage in unanesthetized animals required approximately 25% higher blood withdrawal than anesthetized animals to achieve the same targeted mean arterial blood pressure. Resuscitation with Hextend reestablished circulatory volume and improved survival during resuscitation of awake rodents. Yet, over 75% of the animals resuscitated with Hextend died within the first hours after hemorrhage. Resuscitation with Hextend containing 50 mM ethyl pyruvate protected over 87% of the animals. This survival benefit did not correlate with significant changes in the metabolic markers but with an anti-inflammatory potential during resuscitation. Unlike classical hemorrhage in anesthetized animals, ethyl pyruvate reestablished mean arterial blood pressure significantly earlier than Hextend in unanesthetized rodents. Unanesthetized animals showed twofold higher serum tumor necrosis factor (TNF)-? than anesthetized animals subjected to the same blood pressure. This process was not due to the response of a single organ, but affected all the analyzed organs including the lung, heart, spleen, and liver. Although resuscitation with Hextend failed to attenuate systemic TNF-? levels, it inhibited TNF-? levels in the lung, heart, and liver but not in the spleen. Unlike Hextend, resuscitation with ethyl pyruvate prevented high serum TNF-? levels and blunted TNF-? responses in all the organs including the spleen. These studies indicate that the inflammatory responses in anesthetized animals differ from that in unanesthetized animals and that awake hemorrhage can provide advantages in the study of anti-inflammatory strategies during resuscitation. Ethyl pyruvate may attenuate systemic inflammatory responses during resuscitation and improve survival in experimental models of awake hemorrhage.

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

2011-01-01

280

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

2012-04-01

281

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

282

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

283

Glucuronidation of dihydroartemisinin in vivo and by human liver microsomes and expressed UDP-glucuronosyltransferases.  

PubMed

The aim of this study was to elucidate the metabolic pathways for dihydroartemisinin (DHA), the active metabolite of the artemisinin derivative artesunate (ARTS). Urine was collected from 17 Vietnamese adults with falciparum malaria who had received 120 mg of ARTS i.v., and metabolites were analyzed by high-performance liquid chromatography-mass spectrometry (HPLC-MS). Human liver microsomes were incubated with [12-(3)H]DHA and cofactors for either glucuronidation or cytochrome P450-catalyzed oxidation. Human liver cytosol was incubated with cofactor for sulfation. Metabolites were detected by HPLC-MS and/or HPLC with radiochemical detection. Metabolism of DHA by recombinant human UDP-glucuronosyltransferases (UGTs) was studied. HPLC-MS analysis of urine identified alpha-DHA-beta-glucuronide (alpha-DHA-G) and a product characterized as the tetrahydrofuran isomer of alpha-DHA-G. DHA was present only in very small amounts. The ratio of the tetrahydrofuran isomer, alpha-DHA-G, was highly variable (median 0.75; range 0.09-64). Nevertheless, alpha-DHA-G was generally the major urinary product of DHA glucuronidation in patients. The tetrahydrofuran isomer appeared to be at least partly a product of nonenzymic reactions occurring in urine and was readily formed from alpha-DHA-G by iron-mediated isomerization. In human liver microsomal incubations, DHA-G (diastereomer unspecified) was the only metabolite found (V(max) 177 +/- 47 pmol min(-1) mg(-1), K(m) 90 +/- 16 microM). Alpha-DHA-G was formed in incubations of DHA with expressed UGT1A9 (K(m) 32 microM, V(max) 8.9 pmol min(-1) mg(-1)) or UGT2B7 (K(m) 438 microM, V(max) 10.9 pmol mg(-1) min(-1)) but not with UGT1A1 or UGT1A6. There was no significant metabolism of DHA by cytochrome-P450 oxidation or by cytosolic sulfotransferases. We conclude that alpha-DHA-G is an important metabolite of DHA in humans and that its formation is catalyzed by UGT1A9 and UGT2B7. PMID:12167566

Ilett, Kenneth F; Ethell, Brian T; Maggs, James L; Davis, Timothy M E; Batty, Kevin T; Burchell, Brian; Binh, Tran Quang; Thu, Le Thi Anh; Hung, Nguyen Canh; Pirmohamed, Munir; Park, B Kevin; Edwards, Geoffrey

2002-09-01

284

21 CFR 172.872 - Methyl ethyl cellulose.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Methyl ethyl cellulose. 172.872 Section 172.872 Food...Multipurpose Additives § 172.872 Methyl ethyl cellulose. The food additive methyl ethyl cellulose may be safely used in food in...

2009-04-01

285

Lipoxygenase inhibiting ethyl substituted glycoside from Symplocos racemosa  

Microsoft Academic Search

Phytochemical investigation of Symplocos racemosa resulted in the isolation of a new ethyl substituted glycoside, 1-ethyl brachiose-3?-acetate (1) along with four known compounds ketochaulmoogric acid (2), nonaeicosanol (3), triacontyl palmitate (4) and methyl triacontanoate (5). The substitution of ethyl group on 1 was natural because during the course of extraction and purification ethanol was not used. The structural elucidation of

Muhammad Athar Abbasi; Viqar Uddin Ahmad; Muhammad Zubair; Sarfraz A. Nawaz; Muhammad Arif Lodhi; Umar Farooq; M. Iqbal Choudhary

2005-01-01

286

21 CFR 172.872 - Methyl ethyl cellulose.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2009-04-01 true Methyl ethyl cellulose. 172.872 Section 172.872...Multipurpose Additives § 172.872 Methyl ethyl cellulose. The food additive methyl ethyl cellulose may be safely used in food in...

2010-01-01

287

40 CFR 180.183 - O,O-Diethyl S-[2-(ethyl-thio)ethyl] phosphorodithioate; tolerances for residues.  

Code of Federal Regulations, 2010 CFR

...ethyl] phosphorothioate; disulfoton sulfone, O,O -diethyl S -[2-(ethylsulfonyl...phosphorodithioate; and disulfoton oxygen analog sulfone, O,O -diethyl S -[2-(ethylsulfonyl...ethyl] phosphorothioate; disulfoton sulfone, O,O -diethyl S...

2010-07-01

288

Vapor-Phase Infrared Spectral Study of Weapons-Grade O-Ethyl S- 2(diisopropylamino)ethyl methylphosphonothiolate (VX).  

National Technical Information Service (NTIS)

We report the infrared spectra of weapons-grade 0-ethyl-S-2- (diisopropylamino)ethyl methylphosphonothiolate in the mid-infrared (4000- 550/cm) region. The chemical used in the feedstock was obtained from a ton container and was analyzed by gas chromatogr...

A. C. Samuels B. R. Williams J. R. Miles M. S. Hulet

2012-01-01

289

Quercetin-3-O-glucuronide induces ABCA1 expression by LXR? activation in murine macrophages.  

PubMed

Reverse cholesterol transport (RCT) removes excess cholesterol from macrophages to prevent atherosclerosis. ATP-binding cassette, subfamily A, member 1 (ABCA1) is a crucial cholesterol transporter involved in RCT to produce high density lipoprotein-cholesterol (HDLC), and is transcriptionally regulated by liver X receptor alpha (LXR?), a nuclear receptor. Quercetin is a widely distributed flavonoid in edible plants which prevented atherosclerosis in an animal model. We found that quercetin-3-O-glucuronide (Q3GA), a major quercetin metabolite after absorption from the digestive tract, enhanced ABCA1 expression, in vitro, via LXR? in macrophages. In addition, leaf extracts of a traditional Asian edible plant, Nelumbo nucifera (NNE), which contained abundant amounts of quercetin glycosides, significantly elevated plasma HDLC in mice. We are the first to present experimental evidence that Q3GA induced ABCA1 in macrophages, and to provide an alternative explanation to previous studies on arteriosclerosis prevention by quercetin. PMID:24216107

Ohara, Kazuaki; Wakabayashi, Hideyuki; Taniguchi, Yoshimasa; Shindo, Kazutoshi; Yajima, Hiroaki; Yoshida, Aruto

2013-11-29

290

Sex-Dependent Disposition of Acetaminophen Sulfate and Glucuronide in the in Situ Perfused Mouse Liver  

PubMed Central

Breast cancer resistance protein (BCRP, ABCG2) is expressed in the hepatic canalicular membrane and mediates biliary excretion of xenobiotics including sulfate and glucuronide metabolites of some compounds. Hepatic Bcrp expression is sex-dependent, with higher expression in male mice. The hypothesis that sex-dependent Bcrp expression influences the hepatobiliary disposition of phase II metabolites was tested in the present study using acetaminophen (APAP) and the generated APAP glucuronide (AG) and sulfate (AS) metabolites in single-pass in situ perfused livers from male and female wild-type and Abcg–/– (Bcrp-deficient) mice. Pharmacokinetic modeling was used to estimate parameters governing the hepatobiliary disposition of APAP, AG, and AS. In wild-type mice, the biliary excretion rate constant was 2.5- and 7-fold higher in males than in females for AS and AG, respectively, reflecting male-predominant Bcrp expression. Sex-dependent differences in AG biliary excretion were not observed in Bcrp-deficient mice, and AS biliary excretion was negligible. Interestingly, sex-dependent basolateral excretion of AG (higher in males) and AS (higher in females) was noted in wild-type mice with a similar trend in Bcrp-deficient mouse livers, reflecting an increased rate constant for AG formation in male and AS formation in female mouse livers. In addition, the rate constant for AS basolateral excretion was increased significantly in female mouse livers compared with that in male mouse livers. It is interesting to note that multidrug resistance-associated protein 4 was higher in female than in male mouse livers. In conclusion, sex-dependent differences in conjugation and transporter expression result in profound differences in the hepatobiliary disposition of AG and AS in male and female mouse livers.

Lee, Jin Kyung; Abe, Koji; Bridges, Arlene S.; Patel, Nita J.; Raub, Thomas J.; Pollack, Gary M.; Brouwer, Kim L. R.

2009-01-01

291

Specific localization of quercetin-3-O-glucuronide in human brain.  

PubMed

In recent years, many papers have suggested that dietary flavonoids may exert beneficial effects in the brain tissue for the protection of neurons against oxidative stress and inflammation. However, the bioavailability of flavonoids across the blood-brain barrier and the localization in the brain remain controversial. Thus, we examined the localization of quercetin-3-O-glucuronide (Q3GA), a major phase-II metabolite of quercetin, in the human brain tissues with or without cerebral infarction by immunohistochemical staining using anti-Q3GA antibody. A significant immunoreactivity was observed in the epithelial cells of the choroid plexus, which constitute the structural basis of the blood-cerebrospinal fluid (CSF) barrier, and in the foamy macrophages of recent infarcts. The cellular accumulation of Q3GA was also reproduced in vitro in macrophage-like RAW264, microglial MG6, and brain capillary endothelial RBEC1. It is of interest that a common feature of these cell lines is the deconjugation of Q3GA, resulting in the cellular accumulation of non-conjugated quercetin and the methylated forms. We then examined the anti-inflammatory activity of Q3GA and the deconjugated forms in the lipopolysaccharide-stimulated macrophage cells and revealed that the deconjugated forms (quercetin and a methylated form isorhamnetin), but not Q3GA itself, exhibited inhibitory effects on the inflammatory responses through attenuation of the c-Jun N-terminal kinase pathway. These results suggested that a quercetin glucuronide can pass through the blood-brain barrier, perhaps the CSF barrier, accumulate in specific types of cells, such as macrophages, and act as anti-inflammatory agents in the brain through deconjugation into the bioactive non-conjugated forms. PMID:24893148

Ishisaka, Akari; Mukai, Rie; Terao, Junji; Shibata, Noriyuki; Kawai, Yoshichika

2014-09-01

292

Inhibitory effect of ciprofloxacin on ?-glucuronidase-mediated deconjugation of mycophenolic acid glucuronide.  

PubMed

The interaction between mycophenolate (MPA) and quinolone antibiotics such as ciprofloxacin is considered to reduce the enterohepatic recycling of MPA, which is biotransformed in the intestine from MPA glucuronide (MPAG) conjugate excreted via the biliary system; however, the molecular mechanism underlying this biotransformation of MPA is still unclear. In this study, an in vitro system was established to evaluate ?-glucuronidase-mediated deconjugation and to examine the influence of ciprofloxacin on the enzymatic deconjugation of MPAG and MPA resynthesis. Resynthesis of MPA via deconjugation of MPAG increased in a time-dependent manner from 5 to 60?min in the presence of ?-glucuronidase. Ciprofloxacin and phenolphthalein-?-d-glucuronide (PhePG), a typical ?-glucuronidase substrate, significantly decreased the production of MPA from MPAG in the ?-glucuronidase-mediated deconjugation system. In addition, enoxacin significantly inhibited the production of MPA from MPAG, while levofloxacin and ofloxacin had no inhibitory effect on MPA synthesis. Pharmacokinetic analysis revealed that ciprofloxacin showed a dose-dependent inhibitory effect on MPA production from MPAG via ?-glucuronidase with a half-maximal inhibitory concentration (IC50 ) value of 30.4?µm. While PhePG inhibited the ?-glucuronidase-mediated production of MPA from MPAG in a competitive manner, ciprofloxacin inhibited MPA synthesis via noncompetitive inhibition. These findings suggest that the reduction in the serum MPA concentration during the co-administration of ciprofloxacin is at least in part due to the decreased enterohepatic circulation of MPA because of noncompetitive inhibition of deconjugation of MPAG by intestinal ?-glucuronidase. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24615849

Kodawara, Takaaki; Masuda, Satohiro; Yano, Yoshitaka; Matsubara, Kazuo; Nakamura, Toshiaki; Masada, Mikio

2014-07-01

293

Bis(tri-ethyl-ammonium) chloranilate  

PubMed Central

In the crystal structure of the title compound [systematic name: bis­(tri­ethyl­ammonium) 2,5-di­chloro-3,6-dioxo­cyclo­hexa-1,4-diene-1,4-diolate], 2C6H16N+·C6Cl2O4 2?, the chloranilate anion lies on an inversion center. The tri­ethyl­ammonium cations are linked on both sides of the anion via bifurcated N—H?(O,O) and weak C—H?O hydrogen bonds to give a centrosymmetric 2:1 aggregate. The 2:1 aggregates are further linked by C—H?O hydrogen bonds into a zigzag chain running along [01-1].

Gotoh, Kazuma; Maruyama, Shinpei; Ishida, Hiroyuki

2013-01-01

294

Ethyl ester production from (RBD) palm oil  

Microsoft Academic Search

This work develops a methodology for obtaining ethyl esters from RBD (refined, bleached and deodorised) palm oil by evaluating the oil's transesterification and separation. Two catalysts were first tested (KOH and NaOH) by studying the effect of water presence on the reaction. The separation process was then evaluated by using water and water-salt and water-acid mixtures, establishing the agent offering

Oscar Mauricio Martínez Ávila; Francisco José Sánchez Castellanos; Oscar Yesid; Suárez Palacios

295

Glucuronidation of Dihydrotestosterone and trans-Androsterone by Recombinant UDP-Glucuronosyltransferase (UGT) 1A4: Evidence for Multiple UGT1A4 Aglycone Binding Sites  

PubMed Central

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.

Zhou, Jin; Tracy, Timothy S.

2010-01-01

296

Identification of Flavone Glucuronide Isomers by Metal Complexation and Tandem Mass Spectrometry: Regioselectivity of UDP-Glucuronosyltransferase Isozymes in the Biotransformation of Flavones  

PubMed Central

Flavone Glucuronide isomers of five flavones (chrysin, apigenin, luteolin, baicalein, and scutellarein) were differentiated by collision induced dissociation (CID) of [Co(II) (flavone-H) (4,7-diphenyl-1,10-phenanthroline)2]+ complexes. The complexes were generated via post-column addition of a metal/ligand solution after separation of the glucuronide products generated upon incubation of each flavone with an array of UDP-glucuronosyl-transferase (UGT) isozymes. Elucidation of the glucuronide isomers allowed a systematic investigation of the regioselectivity of twelve human UDP-glucuronosyl-transferase (UGT) isozymes, including eight UGT1A and four UGT2B isozymes. Glucuronidation of the 7-OH position was the preferred site for all the flavones except for luteolin, which possessed adjacent hydroxyl groups on the B ring. For all flavones and UGT isozymes, glucuronidation of the 5-OH position was never observed. As confirmed by the metal complexation/MS/MS strategy, glucuronidation of the 6-OH position only occurred for baicalein and scutellarein when incubated with three of the UGT isozymes.

Robotham, Scott A.; Brodbelt, Jennifer S.

2013-01-01

297

Identification of flavone glucuronide isomers by metal complexation and tandem mass spectrometry: regioselectivity of uridine 5'-diphosphate-glucuronosyltransferase isozymes in the biotransformation of flavones.  

PubMed

Flavone glucuronide isomers of five flavones (chrysin, apigenin, luteolin, baicalein, and scutellarein) were differentiated by collision-induced dissociation of [Co(II) (flavone-H) (4,7-diphenyl-1,10-phenanthroline)(2)](+) complexes. The complexes were generated via postcolumn addition of a metal-ligand solution after separation of the glucuronide products generated upon incubation of each flavone with an array of uridine 5'-diphosphate (UDP)-glucuronosyltransferase (UGT) isozymes. Elucidation of the glucuronide isomers allowed a systematic investigation of the regioselectivity of 12 human UGT isozymes, including 8 UGT1A and 4 UGT2B isozymes. Glucuronidation of the 7-OH position was the preferred site for all the flavones except for luteolin, which possessed adjacent hydroxyl groups on the B ring. For all flavones and UGT isozymes, glucuronidation of the 5-OH position was never observed. As confirmed by the metal complexation/MS/MS strategy, glucuronidation of the 6-OH position only occurred for baicalein and scutellarein when incubated with three of the UGT isozymes. PMID:23362992

Robotham, Scott A; Brodbelt, Jennifer S

2013-02-20

298

Isotopic separations of the drug N-0437 and its diastereoisomeric glucuronides by high-performance liquid chromatography.  

PubMed

During the investigations of the metabolic pathways of the new dopaminergic drug N-0437 we encountered a substantial difference in HPLC-retention times between the metabolites, detected by a uv spectrophotometer, and their tritium-labeled markers, measured off-line by a scintillation counter. These distinct retention times can be ascribed to a phenomenon known as isotopic fractionation. In this article we quantified the isotopic separation by reversed-phase HPLC of the unlabeled N-0437, its deuterated and tritiated analogs, and their corresponding glucuronides, synthesized in vitro by rat liver microsomes. In the separation of the glucuronides we demonstrated that this isotope effect is dependent largely on the eluent pH. PMID:3407936

Gerding, T K; Drenth, B F; de Zeeuw, R A

1988-06-01

299

Glucuronidation of the red clover isoflavone irilone by liver microsomes from different species and human UDP-glucuronosyltransferases.  

PubMed

Red clover (Trifolium pratense L.) is used as a source for isoflavone (IF) dietary supplements. In this study, we focused on the red clover IF irilone (IRI), because of its reported comparatively high bioavailability. Because the conjugative metabolism plays a key role in the elimination of IF, we investigated the species-specific differences and glucuronidation kinetics of IRI using different liver microsomes as well as the recombinant UDP-glucuronosyltransferases (UGTs) 1A1, 1A7, 1A8, 1A9, 1A10, and 2B15. Both possible monoglucuronides, the IRI-O-4'-monoglucuronide (IRI-G4') and the IRI-O-5-monoglucuronide (IRI-G5), were detected. Human liver microsomes (HLM) as well as rat liver microsomes predominantly formed IRI-G5, whereas for porcine liver microsomes, IRI-G4' prevailed. HLM showed an apparent V(max) value of 0.43 nmol/min · mg and an apparent K(m) value of 9.8 ?M for the formation of IRI-G5 and a V(max) of 0.35 nmol/min · mg and a K(m) of 64.7 ?M in the case of IRI-G4'. Formation of both glucuronides was best fit using the substrate inhibition equation. The glucuronidation of IRI by UGTs led to values for the intrinsic clearance varying between 4 and 100 ml/min · mg, with UGT1A7 showing the lowest and UGT1A10 the highest IRI conversion rate. The results indicate that IRI undergoes an efficient glucuronidation, presumably in the intestine and liver, following atypical kinetic profiles. PMID:21177485

Maul, Ronald; Siegl, Diana; Kulling, Sabine E

2011-04-01

300

Determination of Coumarin, 7HydroxyCoumarin, 7Hydroxycoumarin-Glucuronide, and 3Hydroxycoumarin by High-Performance Liquid Chromatography  

Microsoft Academic Search

A selective and sensitive method for the determination of coumarin and its main metabolites 7-hydroxycoumarin, 7-hydroxycoumarin-glucuronide and 3-hydroxycoumarin in human plasma and\\/or urine is described. Coumarin and 7-hydroxycoumarin were extracted from plasma with n-hexane\\/chloroform and with chloroform. After evaporation under vacuum, the residue was redissolved in methanol\\/water and injected onto the HPLC column (LiChroCART 250-4, RP 8e 5 ?m; Merck,

Sheida Sharifi; Hans Christoph Michaelis; Erich Lotterer; Johannes Bircher

1993-01-01

301

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

302

The Impact of Glucuronidation on the Bioactivation and DNA Adduction of the Cooked-Food Carcinogen 2Amino1-methyl-6-phenylimidazo[4,5-b] pyridine in vivo  

Microsoft Academic Search

UDP-glucuronosyltransferases (UGTs) catalyze the glucuronidation of many different chemicals. Glucuronidation is especially important for detoxifying reactive intermediates from metabolic reactions, which otherwise can be biotransformed into highly reactive cytotoxic or carcinogenic species. Detoxification of certain food-borne carcinogenic heterocyclic amines (HAs) is highly dependent on UGT1A-mediated glucuronidation. 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), the most mass abundant carcinogenic HA found in well-done cooked meat, is

M. A. Malfatti; E A Ubick; J S Felton

2005-01-01

303

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

304

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

PubMed

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) PMID:8562297

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

1995-08-01

305

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

2013-07-01

306

Analysis of intact glucuronides and sulfates of serotonin, dopamine, and their phase I metabolites in rat brain microdialysates by liquid chromatography-tandem mass spectrometry.  

PubMed

A method for the analysis of intact glucuronides and sulfates of common neurotransmitters serotonin (5-HT) and dopamine (DA) as well as of 5-hydroxy-3-indoleacetic acid (5-HIAA), 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) in rat brain microdialysates by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. Enzyme-assisted synthesis using rat liver microsomes as a biocatalyst was employed for the production of 5-HT-, 5-HIAA-, DOPAC-, and HVA-glucuronides for reference compounds. The sulfate conjugates were synthesized either chemically or enzymatically using a rat liver S9 fraction. The LC-MS/MS method was validated by determining the limits of detection and quantitation, linearity, and repeatability for the quantitative analysis of 5-HT and DA and their glucuronides, as well as of 5-HIAA, DOPAC, and HVA and their sulfate-conjugates. In this study, 5-HT-glucuronide was for the first time detected in rat brain. The concentration of 5-HT-glucuronide (1.0-1.7 nM) was up to 2.5 times higher than that of free 5-HT (0.4-2.1 nM) in rat brain microdialysates, whereas the concentration of DA-glucuronide (1.0-1.4 nM) was at the same level or lower than the free DA (1.2-2.4 nM). The acidic metabolites of neurotransmitters, 5-HIAA, HVA, and DOPAC, were found in free and sulfated form, whereas their glucuronidation was not observed. PMID:19772284

Uutela, Päivi; Reinilä, Ruut; Harju, Kirsi; Piepponen, Petteri; Ketola, Raimo A; Kostiainen, Risto

2009-10-15

307

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

PubMed

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

2013-10-01

308

Quercetin-3-O-glucuronide induces ABCA1 expression by LXR? activation in murine macrophages  

SciTech Connect

Highlights: •The major circulating quercetin metabolite (Q3GA) activated LXR?. •Q3GA induced ABCA1 via LXR? activation in macrophages. •Nelumbo nucifera leaf extracts contained quercetin glycosides. •N. nucifera leaf extract feeding elevated HDLC in mice. -- Abstract: Reverse cholesterol transport (RCT) removes excess cholesterol from macrophages to prevent atherosclerosis. ATP-binding cassette, subfamily A, member 1 (ABCA1) is a crucial cholesterol transporter involved in RCT to produce high density lipoprotein-cholesterol (HDLC), and is transcriptionally regulated by liver X receptor alpha (LXR?), a nuclear receptor. Quercetin is a widely distributed flavonoid in edible plants which prevented atherosclerosis in an animal model. We found that quercetin-3-O-glucuronide (Q3GA), a major quercetin metabolite after absorption from the digestive tract, enhanced ABCA1 expression, in vitro, via LXR? in macrophages. In addition, leaf extracts of a traditional Asian edible plant, Nelumbo nucifera (NNE), which contained abundant amounts of quercetin glycosides, significantly elevated plasma HDLC in mice. We are the first to present experimental evidence that Q3GA induced ABCA1 in macrophages, and to provide an alternative explanation to previous studies on arteriosclerosis prevention by quercetin.

Ohara, Kazuaki, E-mail: Kazuaki_Ohara@kirin.co.jp [Research Laboratories for Health Science and Food Technologies, Kirin Company Limited, 1-13-5 Fukuura, Kanazawa-ku, Yokohama 236-0004 (Japan)] [Research Laboratories for Health Science and Food Technologies, Kirin Company Limited, 1-13-5 Fukuura, Kanazawa-ku, Yokohama 236-0004 (Japan); Wakabayashi, Hideyuki [Laboratory for New Product Development, Kirin Beverage Company Limited, 1-17-1 Namamugi, Tsurumi-ku, Yokohama 230-8628 (Japan)] [Laboratory for New Product Development, Kirin Beverage Company Limited, 1-17-1 Namamugi, Tsurumi-ku, Yokohama 230-8628 (Japan); Taniguchi, Yoshimasa [Research Laboratories for Health Science and Food Technologies, Kirin Company Limited, 1-13-5 Fukuura, Kanazawa-ku, Yokohama 236-0004 (Japan)] [Research Laboratories for Health Science and Food Technologies, Kirin Company Limited, 1-13-5 Fukuura, Kanazawa-ku, Yokohama 236-0004 (Japan); Shindo, Kazutoshi [Department of Food and Nutrition, Japan Women’s University, 2-8-1 Mejirodai, Bunkyo-ku, Tokyo 112-8681 (Japan)] [Department of Food and Nutrition, Japan Women’s University, 2-8-1 Mejirodai, Bunkyo-ku, Tokyo 112-8681 (Japan); Yajima, Hiroaki [Research Laboratories for Health Science and Food Technologies, Kirin Company Limited, 1-13-5 Fukuura, Kanazawa-ku, Yokohama 236-0004 (Japan)] [Research Laboratories for Health Science and Food Technologies, Kirin Company Limited, 1-13-5 Fukuura, Kanazawa-ku, Yokohama 236-0004 (Japan); Yoshida, Aruto [Central Laboratories for Key Technologies, Kirin Company Limited, 1-13-5 Fukuura, Kanazawa-ku, Yokohama 236-0004 (Japan)] [Central Laboratories for Key Technologies, Kirin Company Limited, 1-13-5 Fukuura, Kanazawa-ku, Yokohama 236-0004 (Japan)

2013-11-29

309

Quantitative Determination of Common Urinary Odorants and Their Glucuronide Conjugates in Human Urine  

PubMed Central

Our previous study on the identification of common odorants and their conjugates in human urine demonstrated that this substance fraction is a little-understood but nonetheless a promising medium for analysis and diagnostics in this easily accessible physiological medium. Smell as an indicator for diseases, or volatile excretion in the course of dietary processes bares high potential for a series of physiological insights. Still, little is known today about the quantitative composition of odorous or volatile targets, as well as their non-volatile conjugates, both with regard to their common occurrence in urine of healthy subjects, as well as in that of individuals suffering from diseases or other physiological misbalancing. Accordingly, the aim of our study was to develop a highly sensitive and selective approach to determine the common quantitative composition of selected odorant markers in healthy human subjects, as well as their corresponding glucuronide conjugates. We used one- and two-dimensional high resolution gas chromatography-mass spectrometry in combination with stable isotope dilution assays to quantify commonly occurring and potent odorants in human urine. The studies were carried out on both native urine and on urine that had been treated by glucuronidase assays, with analysis of the liberated odor-active compounds using the same techniques. Analytical data are discussed with regard to their potential translation as future diagnostic tool.

Wagenstaller, Maria; Buettner, Andrea

2013-01-01

310

The sonic hedgehog factor GLI1 imparts drug resistance through inducible glucuronidation.  

PubMed

Drug resistance is a major hurdle in oncology. Responses of acute myeloid leukaemia (AML) patients to cytarabine (Ara-C)-based therapies are often short lived with a median overall survival of months. Therapies are under development to improve outcomes and include targeting the eukaryotic translation initiation factor (eIF4E) with its inhibitor ribavirin. In a Phase II clinical trial in poor prognosis AML, ribavirin monotherapy yielded promising responses including remissions; however, all patients relapsed. Here we identify a novel form of drug resistance to ribavirin and Ara-C. We observe that the sonic hedgehog transcription factor glioma-associated protein 1 (GLI1) and the UDP glucuronosyltransferase (UGT1A) family of enzymes are elevated in resistant cells. UGT1As add glucuronic acid to many drugs, modifying their activity in diverse tissues. GLI1 alone is sufficient to drive UGT1A-dependent glucuronidation of ribavirin and Ara-C, and thus drug resistance. Resistance is overcome by genetic or pharmacological inhibition of GLI1, revealing a potential strategy to overcome drug resistance in some patients. PMID:24870236

Zahreddine, Hiba Ahmad; Culjkovic-Kraljacic, Biljana; Assouline, Sarit; Gendron, Patrick; Romeo, Andrea A; Morris, Stephen J; Cormack, Gregory; Jaquith, James B; Cerchietti, Leandro; Cocolakis, Eftihia; Amri, Abdellatif; Bergeron, Julie; Leber, Brian; Becker, Michael W; Pei, Shanshan; Jordan, Craig T; Miller, Wilson H; Borden, Katherine L B

2014-07-01

311

Pharmacokinetics of mycophenolic acid and its phenyl glucuronide metabolite in kidney transplant recipients with renal impairment  

PubMed Central

Introduction The aim of the study was to analyse the influence of renal impairment on the pharmacokinetic parameters (PK) of mycophenolic acid (MPA) and its glucuronide metabolite (MPAG) in renal transplant recipients. Material and methods The study included 43 adult patients during the maintenance period (> 6 months) following renal transplantation, treated with mycophenolate mofetil (MMF), calcineurin inhibitors (CNI) (tacrolimus or cyclosporine) and steroids. The study compared patients with normal renal function (n = 17; creatinine clearance (Ccr) > 60 ml/min) and with renal impairment (n = 26; Ccr < 60 ml/min). Areas under the 4-h curve (AUC0-4 h) of MPA and MPAG were determined using a validated HPLC method. Results The renal impairment group showed significantly increased AUC0-4 h and pre-dose (C0) for MPAG compared to patients with normal renal function and increased MPA C0. However, there was no significant difference in MPA AUC0-4 h between patients with renal impairment and patients with normal renal function. In multivariate analysis some MPA and MPAG PK parameters were correlated with sex, CNI co-administered and body weight. Conclusions Although MPAG is an inactive metabolite, its accumulation in patients with renal impairment can be unfavourable. The results of our study indicate that solely MPA C0 determination in patients receiving MMF may be insufficient in clinical practice because of great inter-patient variability of this PK parameter caused mainly by enterohepatic recirculation.

Kaminska, Jolanta; Glyda, Maciej; Sobiak, Joanna

2012-01-01

312

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

313

Nasal administration of morphine-6-glucuronide in sheep--a pharmacokinetic study.  

PubMed

The pharmacokinetics of morphine-6-glucuronide (M6G) after both intravenous dosing and nasal administration were studied in sheep. The nasal formulation consisted of M6G in combination with an absorption promoting delivery system in the form of chitosan. The mean half-life of M6G after intravenous administration was 51.0 +/- 8.2 min and that after intranasal dosing was 45.0 +/- 5.5 min. M6G clearance and volume of distribution were 5.4 +/- 1.5 mL min-1 kg-1 and 0.4 +/- 0.1 L kg-1 respectively. The plasma profile after nasal administration demonstrated rapid absorption of M6G. The bioavailability of M6G in the chitosan formulation was found to be 31.4%. These results suggest that M6G administered in combination with the chitosan delivery system may be considered as a suitable non-parenteral means of administering this analgesic. PMID:8950049

Illum, L; Davis, S S; Pawula, M; Fisher, A N; Barrett, D A; Farraj, N F; Shaw, P N

1996-11-01

314

Sensitive determination of estriol-16-glucuronide using surface plasmon resonance sensing.  

PubMed

For the quantitative evaluation of low levels of an estriol metabolite of estriol (estriol-16-glucuronide (E3-16G)) in liquid media, we developed a simple and highly sensitive immunoassay using a surface plasmon resonance (SPR) biosensor which did not require any time-consuming sample pretreatment steps. E3-16G was conjugated to ovalbumin (OVA) through an oligoethylene glycol (OEG) linker to form protein conjugates (E3-16G-OEG-OVA), which were then immobilized on a carboxymethyl dextran-coated sensor chip via amine coupling to develop inhibition immunoassays. A limit of detection (LOD) of 76 pg/mL was achieved using a rabbit anti-sheep primary antibody as a binding agent. The detection limit was further improved by using synthesized gold colloids (15 nm) as high mass labels conjugated to the primary antibody. In this Au nanoparticle-enhanced assay, the concentration of E3-16G in aqueous samples could be determined in 7.5 min at a level as low as 14 pg/mL. In addition, the high stability of the E3-16G-OEG-OVA surface gave no obvious drop in antibody-binding capability after more than 1000 binding/regeneration cycles which significantly lowered the research cost. PMID:19465041

Jiang, Xiuqian; Waterland, Mark; Blackwell, Len; Wu, Yinqiu; Jayasundera, Krishanthi P; Partridge, Ashton

2009-10-01

315

Genetic predisposition to the metabolism of irinotecan (CPT-11). Role of uridine diphosphate glucuronosyltransferase isoform 1A1 in the glucuronidation of its active metabolite (SN-38) in human liver microsomes.  

PubMed Central

Irinotecan (CPT-11) is a promising antitumor agent, recently approved for use in patients with metastatic colorectal cancer. Its active metabolite, SN-38, is glucuronidated by hepatic uridine diphosphate glucuronosyltransferases (UGTs). The major dose-limiting toxicity of irinotecan therapy is diarrhea, which is believed to be secondary to the biliary excretion of SN-38, the extent of which is determined by SN-38 glucuronidation. The purpose of this study was to identify the specific isoform of UGT involved in SN-38 glucuronidation. In vitro glucuronidation of SN-38 was screened in hepatic microsomes from normal rats (n = 4), normal humans (n = 25), Gunn rats (n = 3), and patients (n = 4) with Crigler-Najjar type I (CN-I) syndrome. A wide intersubject variability in in vitro SN-38 glucuronide formation rates was found in humans. Gunn rats and CN-I patients lacked SN-38 glucuronidating activity, indicating the role of UGT1 isoform in SN-38 glucuronidation. A significant correlation was observed between SN-38 and bilirubin glucuronidation (r = 0.89; P = 0.001), whereas there was a poor relationship between para-nitrophenol and SN-38 glucuronidation (r = 0.08; P = 0.703). Intact SN-38 glucuronidation was observed only in HK293 cells transfected with the UGT1A1 isozyme. These results demonstrate that UGT1A1 is the isoform responsible for SN-38 glucuronidation. These findings indicate a genetic predisposition to the metabolism of irinotecan, suggesting that patients with low UGT1A1 activity, such as those with Gilbert's syndrome, may be at an increased risk for irinotecan toxicity.

Iyer, L; King, C D; Whitington, P F; Green, M D; Roy, S K; Tephly, T R; Coffman, B L; Ratain, M J

1998-01-01

316

Genetic predisposition to the metabolism of irinotecan (CPT-11). Role of uridine diphosphate glucuronosyltransferase isoform 1A1 in the glucuronidation of its active metabolite (SN-38) in human liver microsomes.  

PubMed

Irinotecan (CPT-11) is a promising antitumor agent, recently approved for use in patients with metastatic colorectal cancer. Its active metabolite, SN-38, is glucuronidated by hepatic uridine diphosphate glucuronosyltransferases (UGTs). The major dose-limiting toxicity of irinotecan therapy is diarrhea, which is believed to be secondary to the biliary excretion of SN-38, the extent of which is determined by SN-38 glucuronidation. The purpose of this study was to identify the specific isoform of UGT involved in SN-38 glucuronidation. In vitro glucuronidation of SN-38 was screened in hepatic microsomes from normal rats (n = 4), normal humans (n = 25), Gunn rats (n = 3), and patients (n = 4) with Crigler-Najjar type I (CN-I) syndrome. A wide intersubject variability in in vitro SN-38 glucuronide formation rates was found in humans. Gunn rats and CN-I patients lacked SN-38 glucuronidating activity, indicating the role of UGT1 isoform in SN-38 glucuronidation. A significant correlation was observed between SN-38 and bilirubin glucuronidation (r = 0.89; P = 0.001), whereas there was a poor relationship between para-nitrophenol and SN-38 glucuronidation (r = 0.08; P = 0.703). Intact SN-38 glucuronidation was observed only in HK293 cells transfected with the UGT1A1 isozyme. These results demonstrate that UGT1A1 is the isoform responsible for SN-38 glucuronidation. These findings indicate a genetic predisposition to the metabolism of irinotecan, suggesting that patients with low UGT1A1 activity, such as those with Gilbert's syndrome, may be at an increased risk for irinotecan toxicity. PMID:9466980

Iyer, L; King, C D; Whitington, P F; Green, M D; Roy, S K; Tephly, T R; Coffman, B L; Ratain, M J

1998-02-15

317

Disruption of thyroid hormone homeostasis in Ugt1a-deficient Gunn rats by microsomal enzyme inducers is not due to enhanced thyroxine glucuronidation  

SciTech Connect

Microsomal enzyme inducers (MEI) that increase UDP-glucuronosyltransferases (UGTs) are thought to increase glucuronidation of thyroxine (T{sub 4}), thus reducing serum T{sub 4}, and subsequently increasing thyroid stimulating hormone (TSH). Ugt1a1 and Ugt1a6 mediate T{sub 4} glucuronidation. Therefore, this experiment determined the involvement of Ugt1a enzymes in increased T{sub 4} glucuronidation, decreased serum T{sub 4}, and increased TSH after MEI treatment. Male Wistar and Ugt1a-deficient Wistar (Gunn) rats were fed a control diet or diet containing pregnenolone-16{alpha}-carbonitrile (PCN; 800 ppm), 3-methylcholanthrene (3-MC; 200 ppm), or Aroclor 1254 (PCB; 100 ppm) for 7 days. Serum T{sub 4}, triiodothyronine (T{sub 3}), and TSH concentrations, hepatic T{sub 4}/T{sub 3} glucuronidation, and thyroid histology and follicular cell proliferation were investigated. PCN, 3-MC, and PCB treatments decreased serum T{sub 4}, whereas serum T{sub 3} was maintained in both Gunn and Wistar rats (except for PCB treatment). TSH was increased in Wistar and Gunn rats after PCN (130 and 277%) or PCB treatment (72 and 60%). T{sub 4} glucuronidation in Wistar rats was increased after PCN (298%), 3-MC (85%), and PCB (450%), but was extremely low in Gunn rats, and unchanged after MEI. T{sub 3} glucuronidation was increased after PCN (121%) or PCB (58%) in Wistar rats, but only PCN increased T{sub 3} glucuronidation in Gunn rats (43%). PCN treatment induced thyroid morphological changes and increased follicular cell proliferation in both strains. These data demonstrate that T{sub 4} glucuronidation cannot be increased in Ugt1a-deficient Gunn rats. Thus, the decrease in serum T{sub 4}, increase in TSH, and increase in thyroid cell proliferation after MEI are not dependent on increased T{sub 4} glucuronidation, and cannot be attributed to Ugt1a enzymes.

Richardson, Terrilyn A.; Klaassen, Curtis D., E-mail: cklaasse@kumc.ed

2010-10-01

318

Simultaneous determination of morphine and its glucuronides in rat hair and rat plasma by reversed-phase liquid chromatography with electrospray ionization mass spectrometry.  

PubMed

The simultaneous determination of morphine and the glucuronide metabolites [morphine-3-beta-D-glucuronide (M3G) and morphine-6-beta-D-glucuronide (M6G)] in rat hair and rat plasma was carried out using reversed-phase high-performance liquid chromatography (HPLC) coupled with electrospray ionization mass spectrometry (ESI-MS). The chromatographic separation of the analytes was achieved using a semi-micro-HPLC column (3 microm particle size; 100 x 2.0 mm id) by gradient elution with 50 mM ammonium acetate and acetonitrile as eluents. After separation, morphine and the glucuronides were determined by selected ion monitoring (SIM) of ESI-MS using the quasi-molecular ions [M + H]+ at m/z = 286 and 462, respectively. The calibration curves were linear between the concentration of the analytes and the deuterium-labelled morphine (M-d3) selected as internal standard. The method was applied for the determination of the incorporation of morphine and the glucuronides into the hair shafts and hair roots of Dark Agouti rats after single intraperitoneal administration of morphine hydrochloride. Plasma concentrations of morphine and glucuronides were simultaneously determined after administration. Morphine and M3G were detected in the hair shafts and the hair roots. The concentrations of M3G in the hair root were lower than those of morphine in all sampling periods. In contrast, M3G concentrations in plasma were relatively higher at each sampling time. Small quantities of M6G were also identified in the plasma up to 4 h after administration. The concentration difference between the hair root and plasma seems to be due to the incorporation ratio of morphine and glucuronide into hair. As M3G was also identified in the hair shaft 1 week after administration, the incorporation of glucuronide metabolites into hair is obvious. This is the first report of the identification of morphine glucuronide in hair samples without the use of acid hydrolysis or enzyme digestion. PMID:11534602

Toyo'oka, T; Yano, M; Kato, M; Nakahara, Y

2001-08-01

319

Use of Isoform-Specific UGT Metabolism to Determine and Describe Rates and Profiles of Glucuronidation of Wogonin and Oroxylin A by Human Liver and Intestinal Microsomes  

PubMed Central

Purposes Glucuronidation via UDP-glucuronosyltransferases (or UGTs) is a major metabolic pathway. The purposes of this study are to determine the UGT-isoform specific metabolic fingerprint (or GSMF) of wogonin and oroxylin A, and to use isoform-specific metabolism rates and kinetics to determine and describe their glucuronidation behaviors in tissue microsomes. Methods In vitro glucuronidation rates and profiles were measured using expressed UGTs and human intestinal and liver microsomes. Results GSMF experiments indicated that both flavonoids were metabolized mainly by UGT1As, with major contributions from UGT1A3 and UGT1A7-1A10. Isoform-specific metabolism showed that kinetic profiles obtained using expressed UGT1A3 and UGT1A7-1A10 could fit to known kinetic models. Glucuronidation of both flavonoids in human intestinal and liver microsomes followed simple Michaelis-Menten kinetics. A comparison of the kinetic parameters and profiles suggests that UGT1A9 is likely the main isoform responsible for liver metabolism. In contrast, a combination of UGT1As with a major contribution from UGT1A10 contributed to their intestinal metabolism. Correlation studies clearly showed that UGT isoform-specific metabolism could describe their metabolism rates and profiles in human liver and intestinal microsomes. Conclusion GSMF and isoform-specific metabolism profiles can determine and describe glucuronidation rates and profiles in human tissue microsomes.

Zhou, Qiong; Zheng, Zhijie; Xia, Bijun; Tang, Lan; Lv, Chang; Liu, Wei; Liu, Zhongqiu; Hu, Ming

2010-01-01

320

Ethyl trifluoroacetate: a powerful reagent for differentiating amino groups  

Microsoft Academic Search

Selective protection of primary amines in the presence of secondary amines and monofunctionalization of symmetric primary and secondary diamines using ethyl trifluoroacetate is described. Effective differentiation of primary, secondary and tertiary alkyl-substituted primary amines from one another by ethyl trifluoroacetate acylation is also demonstrated. These results are explained on the basis of steric and electronic effects of the substrate amines.

Daqiang Xu; Kapa Prasad; Oljan Repic; Thomas J. Blacklock

1995-01-01

321

Ethyl-enediammonium dichloro-iodide chloride  

PubMed Central

The asymmetric unit of the crystal structure of the title compound, C2H10N2 2+·Cl2I?·Cl?, contains two ethyl­ene­diammonium cations, two [ICl2]? anions and two Cl? anions, of which one cation, one [ICl2]? anion and one Cl? anion have site symmetry 2, with the mid-point of the C—C bond of the cation, the I atom of [ICl2]? anion and the Cl? anion located on the twofold rotation axes. The two independent cations show different conformations, the N—C—C—N torsion angles being 160.1?(2) and ?73.1?(4)°. The crystal structure is stabilized by extensive inter­molecular N—H?Cl hydrogen bonding.

Chen, Li-Zhuang

2009-01-01

322

Enhanced ethyl butyrate production using immobilized lipase.  

PubMed

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

2013-10-01

323

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

324

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

325

40 CFR 721.7290 - Propanoic acid, 2-(trimethoxysilyl)-, ethyl ester.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 false Propanoic acid, 2-(trimethoxysilyl)-, ethyl ester. 721.7290...721.7290 Propanoic acid, 2-(trimethoxysilyl)-, ethyl ester. (a) Chemical...identified as propanoic acid, 2-(trimethoxysilyl)-, ethyl ester (PMN...

2009-07-01

326

40 CFR 721.7290 - Propanoic acid, 2-(trimethoxysilyl)-, ethyl ester.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Propanoic acid, 2-(trimethoxysilyl)-, ethyl ester. 721.7290...721.7290 Propanoic acid, 2-(trimethoxysilyl)-, ethyl ester. (a) Chemical...identified as propanoic acid, 2-(trimethoxysilyl)-, ethyl ester (PMN...

2013-07-01

327

40 CFR 721.7290 - Propanoic acid, 2-(trimethoxysilyl)-, ethyl ester.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Propanoic acid, 2-(trimethoxysilyl)-, ethyl ester. 721.7290...721.7290 Propanoic acid, 2-(trimethoxysilyl)-, ethyl ester. (a) Chemical...identified as propanoic acid, 2-(trimethoxysilyl)-, ethyl ester (PMN...

2010-07-01

328

Fragmentation dynamics of the ethyl bromide and ethyl iodide cations: a velocity-map imaging study.  

PubMed

The photodissociation dynamics of ethyl bromide and ethyl iodide cations (C2H5Br(+) and C2H5I(+)) have been studied. Ethyl halide cations were formed through vacuum ultraviolet (VUV) photoionization of the respective neutral parent molecules at 118.2 nm, and were photolysed at a number of ultraviolet (UV) photolysis wavelengths, including 355 nm and wavelengths in the range from 236 to 266 nm. Time-of-flight mass spectra and velocity-map images have been acquired for all fragment ions and for ground (Br) and spin-orbit excited (Br*) bromine atom products, allowing multiple fragmentation pathways to be investigated. The experimental studies are complemented by spin-orbit resolved ab initio calculations of cuts through the potential energy surfaces (along the RC-Br/I stretch coordinate) for the ground and first few excited states of the respective cations. Analysis of the velocity-map images indicates that photoexcited C2H5Br(+) cations undergo prompt C-Br bond fission to form predominantly C2H5(+) + Br* products with a near-limiting 'parallel' recoil velocity distribution. The observed C2H3(+) + H2 + Br product channel is thought to arise via unimolecular decay of highly internally excited C2H5(+) products formed following radiationless transfer from the initial excited state populated by photon absorption. Broadly similar behaviour is observed in the case of C2H5I(+), along with an additional energetically accessible C-I bond fission channel to form C2H5 + I(+) products. HX (X = Br, I) elimination from the highly internally excited C2H5X(+) cation is deemed the most probable route to forming the C2H4(+) fragment ions observed from both cations. Finally, both ethyl halide cations also show evidence of a minor C-C bond fission process to form CH2X(+) + CH3 products. PMID:24317740

Gardiner, Sara H; Karsili, Tolga N V; Lipciuc, M Laura; Wilman, Edward; Ashfold, Michael N R; Vallance, Claire

2014-02-01

329

Tissue distributions of 4-(hydroxymethylnitrosamino)-1-(3-pyridyl)-1-butanone glucuronide, a stable form of reactive intermediate produced from 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, in the rat.  

PubMed

The tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), induces lung tumors in rodents and has been suggested as a causative factor in human lung cancer. NNK is activated by ?-hydroxylation at either the methyl or methylene carbon adjacent to the N-nitroso group to yield unstable intermediates that spontaneously decompose to produce alkylating agents. 4-(Hydroxymethylnitrosamino)-1-(3-pyridyl)-1-butanone (HO-methyl NNK) glucuronide, a glucuronide of the reactive intermediate of NNK has been identified. However, there are no available data concerning HO-methyl NNK glucuronide. In the present study, we investigated the tissue distribution of HO-methyl NNK glucuronide in control and phenobarbital (PB)-treated rats after intraperitoneal administration of NNK. In PB-treated rats, HO-methyl NNK glucuronide was detected in plasma, kidney, liver, lung, and pancreas. On the contrary, in the control rats, HO-methyl NNK glucuronide was detected only in plasma, kidney and liver at low concentrations compared with PB-treated rats. The results of cumulative urinary excretion of HO-methyl NNK glucuronide in Wistar and Gunn rats suggested that PB-inducible UDP-glucuronosyltransferase 2B isoforms mainly contribute to the formation of HO-methyl NNK glucuronide. PMID:24646707

Nishiyama, Takahito; Ogura, Kenichiro; Ohnuma, Tomokazu; Hiratsuka, Akira

2014-01-01

330

Gemfibrozil and its glucuronide inhibit the hepatic uptake of pravastatin mediated by OATP1B1.  

PubMed

When pravastatin (40 mg/day) was co-administered with gemfibrozil (600 mg, b.i.d., 3 days) to man, the AUC of pravastatin increased approximately 2-fold. We have clarified that OATP1B1 is a key determinant of the hepatic uptake of pravastatin in humans. Thus, we hypothesized that gemfibrozil and the main plasma metabolites, a glucuronide (gem-glu) and a carboxylic acid metabolite (gem-M3), might inhibit the hepatic uptake of pravastatin and lead to the elevation of the plasma concentration of pravastatin. Gemfibrozil and gem-glu inhibited the uptake of (14)C-pravastatin by human hepatocytes with K(i) values of 31.7 microM and 15.7 microM, respectively and also inhibited pravastatin uptake by OATP1B1-expressing Xenopus laevis oocytes with K(i) values of 15.1 microM and 7.6 microM. Additionally, we examined the biliary transport of pravastatin and demonstrated that pravastatin was transported by MRP2 using both human canalicular membrane vesicles (hCMVs) and human MRP2-expressing vesicles. However, gemfibrozil, gem-glu and gem-M3 did not affect the biliary transport of pravastatin by MRP2. Considering the plasma concentrations of gemfibrozil and gem-glu in humans, the inhibition of OATP1B1-mediated hepatic uptake of pravastatin by gem-glu would contribute, at least in part, to the elevation of plasma concentration of pravastatin by the concomitant use of gemfibrozil. PMID:17523051

Nakagomi-Hagihara, R; Nakai, D; Tokui, T; Abe, T; Ikeda, T

2007-05-01

331

Efflux transport is an important determinant of ethinylestradiol glucuronide and ethinylestradiol sulfate pharmacokinetics.  

PubMed

17?-ethinylestradiol (EE) undergoes extensive conjugation to 17?-ethinylestradiol-3-O-glucuronide (EEG) and 17?-ethinylestradiol-3-O-sulfate (EES). Thus, oral contraceptive drug-drug interaction (DDI) studies usually characterize metabolite pharmacokinetics, with changes typically attributed to modulation of metabolism. EE passively diffuses through plasma membranes, but its conjugates are hydrophilic and require active transport. Unlike EE metabolism, EEG and EES transport has not been explored in vivo as a potential mechanism of DDIs. Recent in vitro studies demonstrated that EEG is transported by multidrug resistance-associated protein (MRP) 2 and MRP3 and EES is a breast cancer resistance protein (BCRP) substrate. In the study presented here, pharmacokinetics of EE and conjugates were studied in TR? rats, which lack Mrp2, have marginal hepatic Bcrp expression, and overexpress hepatic Mrp3. EE pharmacokinetics in TR? rats were comparable to wild type; however, EEG and EES systemic exposures were altered markedly. EEG exposure was greatly increased: 20-fold and >100-fold after intravenous and oral EE administration, respectively. In contrast, EES exposure was lower in TR? rats: 65% decreased (intravenously) and 83% decreased (orally). In intestinal and liver perfusions, EE intestinal permeability and metabolism and hepatic clearance were unchanged in TR? rats; however, secretion of EEG into intestinal lumen was halved, EEG was not detected in TR? bile, and EES biliary excretion was 98% decreased. After oral EE administration to Mrp2- and Bcrp-knockout mice, EEG exposure increased 46- and 2-fold, respectively, whereas EES concentrations were decreased modestly. In conclusion, altered efflux transport resulted in major alterations of EEG and EES pharmacokinetics, highlighting transport as a potential site of DDIs with EE conjugates. PMID:21708882

Zamek-Gliszczynski, Maciej J; Day, Jeffrey S; Hillgren, Kathleen M; Phillips, Diane L

2011-10-01

332

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

PubMed

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 for specific recognition. A preliminary investigation of the imprinting properties of eleven MIPs was carried out, by comparing the retention time of the template and of structurally related compounds on the MIP column with that on the corresponding non-imprinted polymer (NIP). The two polymers showing the best performance were selected to further test cotinine, mycophenolic acid, testosterone and their respective glucuronides as model compounds. The high specificity obtained against glucuronides and the different chemical structure of the parent drug make the two MIPs class-selective imprinted receptors, also suitable for SPE application. PMID:21871628

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

2011-09-28

333

Bioactive Androgens and Glucuronidated Androgen Metabolites are Associated with Subcutaneous and Ectopic Skeletal Muscle Adiposity among Older Black Men  

PubMed Central

Aging is associated with declining serum levels of androgenic hormones and with increased skeletal muscle fat infiltration, an emerging risk factor for type 2 diabetes mellitus (T2DM). Androgens regulate fat mass and glucose homeostasis, but the effect of androgenic hormones on skeletal muscle fat infiltration is largely unknown. Thus, the aim of the current study was to examine the association of serum androgens and their precursors and metabolites with skeletal muscle fat infiltration and T2DM in a black male population group at high risk of T2DM. Serum androgens, estrogens, and androgen precursors and metabolites were measured using mass spectrometry, and calf skeletal muscle fat distribution [subcutaneous and intermuscular fat; skeletal muscle density] were measured using quantitative computed tomography in 472 Afro-Caribbean men aged 65 and older. Bioactive androgens, testosterone, free testosterone and dihydrotestosterone, were associated with less skeletal muscle fat infiltration (r=?0.14 to ?0.18, P<0.05) and increased skeletal muscle density (r=0.10 to 0.14, P<0.05), independent of total adiposity. Additionally, glucuronidated androgen metabolites were associated with less subcutaneous fat (r=?0.11 to ?0.15, P<0.05). Multivariate logistic regression analysis identified an increased level of 3?-diol-3 glucuronide (OR=1.38, P<0.01) and a decreased level of dihydrotestosterone (OR=0.66, P<0.01) to be significantly associated with T2DM. Our findings suggest that in elderly black men, independent of total adiposity, bioactive androgens and glucuronidated androgen metabolites may play previously unrecognized role in skeletal muscle fat distribution. Longitudinal studies are needed to further evaluate the relationship between androgens and androgen metabolites with changes in skeletal muscle fat distribution with aging and the incidence of T2DM.

Miljkovic, Iva; Cauley, Jane A; Dressen, Amy S; Gordon, Christopher L; Goodpaster, Bret H; Kuller, Lewis H; Bunker, Clareann H; Patrick, Alan L; Wheeler, Victor W; Orwoll, Eric S; Zmuda, Joseph M

2011-01-01

334

Sudan-?-d-glucuronides and their use for the histochemical localization of ?-glucuronidase activity in transgenic plants  

Microsoft Academic Search

Synthesis of five different Sudan-?-d-glucuronides (I, II, III, IV, and RedB) was performed by condensation of a set of red Sudan diazo dyes with methyl (1-deoxy-2,3,4-tri-O-acetyl-1-trichloroacetimidoyl-?-d-glucopyran)uronate. After the acid and alcohol groups had been deprotected, the resulting compounds were used for histochemical\\u000a localization of ?-glucuronidase (GUS) activity in transgenic plants (Petunia hybrida, Arabidopsis thaliana, and Nicotiana tabacum) that contained the

E. Van der Eycken; N. Terryn; J. L. Goeman; G. Carlens; W. Nerinckx; M. Claeyssens; J. Van der Eycken; M. Van Montagu; M. Brito-Arias; G. Engler

2000-01-01

335

Evaluation of pharmaceutical excipients as cosolvents in 4-methyl umbelliferone glucuronidation in human liver microsomes: applications for compounds with low solubility.  

PubMed

Standard incubation procedures for carrying out microsomal assays involve the use of less than 1% w/v organic solvents to minimize the potential inhibitory effects of organic solvents on metabolic activity. This presents a practical limitation for poorly soluble xenobiotics, which cannot be incubated at concentrations high enough to obtain a V(max), and therefore subsequent values for K(m) and Cl(int) cannot be calculated. Our goal was to study the application of a variety of pharmaceutical excipients to aid the solubilization of compounds in vitro in glucuronidation incubations, without affecting the reaction kinetics. In vitro glucuronidation incubations were carried out in human liver microsomes with 4-methylumbelliferone (4-MU) and the kinetics of 4-MU glucuronidation in the presence of excipients were compared to that in control incubations without any excipients. In addition, IC(75) values were calculated for each excipient. We observed that HPBCD (Hydroxypropyl-?-cyclodextrin) may be employed in in vitro glucuronidation incubations up to 0.5% w/v without affecting the Cl(int) of 4-MU. Although NMP (N-methyl-2-pyrrolidone) and DMA (N,N-dimethylacetamide); showed low IC(75) values approximately 0.1% w/v each, neither excipients altered the Cl(int) of 4-MUG (4-methylumbelliferyl-?-D-glucuronide) formation. Our studies point toward possible applications of pharmaceutical excipients to carry out in vitro glucuronidation of substrates with poor aqueous solubility, in order to estimate Cl(int) and subsequently scaled organ clearance values. PMID:21084760

Argikar, Upendra A; Liang, Guiqing; Bushee, Jennifer L; Hosagrahara, Vinayak P; Lee, Wendy

2011-01-01

336

[Direct metabolites of ethanol as biological markers of alcohol use: basic aspects and applications].  

PubMed

In addition to self reports and questionnaires, biomarkers are of relevance in the diagnosis of and therapy for alcohol use disorders. Traditional biomarkers such as gamma-glutamyl transpeptidase or mean corpuscular volume are indirect biomarkers and are subject to the influence of age, gender and non-alcohol related diseases, among others. Direct metabolites of ethanol such as ethyl glucuronide (EtG), ethyl sulphate (EtS) and phosphatidylethanol (PEth) are direct metabolites of ethanol, that are positive after intake of ethyl alcohol. They represent useful diagnostic tools for identifying alcohol use even more accurately than traditional biomarkers. Each of these drinking indicators remains positive in serum and urine for a characteristic time spectrum after the cessation of ethanol intake - EtG and EtS in urine up to 7 days, EtG in hair for months after ethanol has left the body. Applications include clinical routine use, emergency room settings, proof of abstinence in alcohol rehabilitation programmes, driving under influence offenders, workplace testing, assessment of alcohol intake in the context of liver transplantation and foetal alcohol syndrome. Due to their properties, they open up new perspectives for prevention, interdisciplinary cooperation, diagnosis of and therapy for alcohol-related problems. PMID:23856980

Thon, N; Weinmann, W; Yegles, M; Preuss, U; Wurst, F M

2013-09-01

337

Perspectives for the biotechnological production of ethyl acetate by yeasts.  

PubMed

Ethyl acetate is an environmentally friendly solvent with many industrial applications. The production of ethyl acetate currently proceeds by energy-intensive petrochemical processes which are based on natural gas and crude oil without exception. Microbial synthesis of ethyl acetate could become an interesting alternative. The formation of esters as aroma compounds in food has been repeatedly reviewed, but a survey which deals with microbial synthesis of ethyl acetate as a bulk product is missing. The ability of yeasts for producing larger amounts of this ester is known for a long time. In the past, this potential was mainly of scientific interest, but in the future, it could be applied to large-scale ester production from renewable raw materials. Pichia anomala, Candida utilis, and Kluyveromyces marxianus are yeasts which convert sugar into ethyl acetate with a high yield where the latter is the most promising one. Special attention was paid to the mechanism of ester synthesis including regulatory aspects and to the maximum and expectable yield. Synthesis of much ethyl acetate requires oxygen which is usually supplied by aeration. Ethyl acetate is highly volatile so that aeration results in its phase transfer and stripping. This stripping process cannot be avoided but requires adequate handling during experimentation and offers a chance for a cost-efficient process-integrated recovery of the synthesized ester. PMID:24788328

Löser, Christian; Urit, Thanet; Bley, Thomas

2014-06-01

338

Lipoxygenase inhibiting ethyl substituted glycoside from Symplocos racemosa.  

PubMed

Phytochemical investigation of Symplocos racemosa resulted in the isolation of a new ethyl substituted glycoside, 1-ethyl brachiose-3'-acetate (1) along with four known compounds ketochaulmoogric acid (2), nonaeicosanol (3), triacontyl palmitate (4) and methyl triacontanoate (5). The substitution of ethyl group on 1 was natural because during the course of extraction and purification ethanol was not used. The structural elucidation of the isolated compounds was based primarily on 1D- and 2D-NMR analysis, including COSY, HMQC, and HMBC correlations. The glycoside 1 and triacontyl palmitate (4) displayed the inhibitory potential against lipoxygenase and urease enzyme, respectively. PMID:15938197

Abbasi, Muhammad Athar; Ahmad, Viqar Uddin; Zubair, Muhammad; Nawaz, Sarfraz A; Lodhi, Muhammad Arif; Farooq, Umar; Choudhary, M Iqbal

2005-07-01

339

Simultaneous evaluation of six human glucuronidation activities in liver microsomes using liquid chromatography-tandem mass spectrometry.  

PubMed

This article describes the development of a procedure for the simultaneous evaluation of the activity of six different uridine diphosphate (UDP)-glucuronyltransferases (UGTs) in human liver microsomes (HLMs). The method consists of incubations of probe substrates for UGT1A1 (etoposide), UGT1A3 (chenodeoxycholic acid), UGT1A4 (trifluoperazine), UGT1A6 (serotonin), UGT1A9 (mefenamic acid), and UGT2B7 (azidothymidine) with HLMs. The six substrates were divided into three different incubations (etoposide + mefenamic acid; chenodeoxycholic acid + serotonin + azidothymidine; and trifluoperazine alone), the media of which were pooled before analysis. Glucuronide formation rates were determined in a single run of 20 min using a validated liquid chromatography-tandem mass spectrometry method. No significant difference was observed between glucuronidation activities measured using the current procedure and individual incubations of the probes. The method was used successfully for the determination of UGT activities in 44 individual HLM preparations and for the phenotyping of preparations predicted to have altered UGT1A1 and UGT2B7 activities because of known genetic polymorphisms. PMID:22579593

Gagez, Anne-Laure; Rouguieg-Malki, Koukeb; Sauvage, François-Ludovic; Marquet, Pierre; Picard, Nicolas

2012-08-01

340

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

2009-10-16

341

Textures of Ethyl Cellulose-Dichloroacetic Acid Mesomorphic Solution.  

National Technical Information Service (NTIS)

Textures of the ethyl cellulose (eC)-dichloracetic acid (DCA) mesomorphic solution were studied systematically by polarizing microscopy and small-angle light scattering. It was found that with increasing polymer concentration, the mesophase could show a d...

Y. Huang, J. Y. Zhou

1994-01-01

342

Supercritical carbon dioxide extraction of CLA-ethyl ester  

Microsoft Academic Search

Supercritical carbon dioxide (SC-CO2) extraction of Conjugated linoleic acid (CLA) ethyl ester was investigated at pressures in the range of 9 to 10.5 MPa and\\u000a temperature gradients ranging from 0°C to 21°C. The content of CLA-ethyl ester in the fraction was analyzed with gas chromatography\\u000a (GC). The experimental results indicated that the rate of extraction would rise with the increase

Yingdi Chen; Peng Xu; Jian Cheng

2011-01-01

343

Enteric Excretion of Baicalein, a Flavone of Scutellariae Radix, via Glucuronidation in Rat: Involvement of Multidrug Resistance-Associated Protein 2  

Microsoft Academic Search

Purpose. Baicalin (BG) and its aglycone, baicalein (B), are strong antioxidants and have various pharmacological actions. The purpose of this study was to evaluate efflux of BG from rat intestinal mucosal cell following glucuronidation of B absorbed after oral administration of B.

Teruaki Akao; Yoko Sakashita; Masato Hanada; Hirozo Goto; Yutaka Shimada; Katsutoshi Terasawa

2004-01-01

344

Dipeptidyl peptidase IV is a target for covalent adduct formation with the acyl glucuronide metabolite of the anti-inflammatory drug zomepirac  

Microsoft Academic Search

The nonsteroidal anti-inflammatory drug zomepirac (ZP) is metabolised to a chemically reactive acyl glucuronide conjugate (ZAG) which can form covalent adducts with proteins. In vivo, such adducts could initiate immune or toxic responses. In rats given ZP, the major band detected in liver homogenates by immunoblotting with a polyclonal ZP antiserum was at 110 kDa. This adduct was identified as

Min Wang; Mark D. Gorrell; Geoffrey W. McCaughan; Ronald G. Dickinson

2001-01-01

345

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

2013-12-01

346

Antioxidant activity of phenolic acids and their metabolites: synthesis and antioxidant properties of the sulfate derivatives of ferulic and caffeic acids and of the acyl glucuronide of ferulic acid.  

PubMed

The main metabolites of caffeic and ferulic acids (ferulic acid-4'-O-sulfate, caffeic acid-4'-O-sulfate, and caffeic acid-3'-O-sulfate), the most representative phenolic acids in fruits and vegetables, and the acyl glucuronide of ferulic acid were synthesized, purified, and tested for their antioxidant activity in comparison with those of their parent compounds and other related phenolics. Both the ferric reducing antioxidant power (FRAP) assay and the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging method were used. Ferulic acid-4'-O-sulfate and ferulic acid-4'-O-glucuronide exhibited very low antioxidant activity, while the monosulfate derivatives of caffeic acid were 4-fold less efficient as the antioxidant than caffeic acid. The acyl glucuronide of ferulic acid showed strong antioxidant action. The antioxidant activity of caffeic acid-3'-O-glucuronide and caffeic acid-4'-O-glucuronide was also studied. Our results demonstrate that some of the products of phenolic acid metabolism still retain strong antioxidant properties. Moreover, we first demonstrate the ex vivo synthesis of the acyl glucuronide of ferulic acid by mouse liver microsomes, in addition to the phenyl glucuronide. PMID:23157164

Piazzon, A; Vrhovsek, U; Masuero, D; Mattivi, F; Mandoj, F; Nardini, M

2012-12-19

347

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

348

Aza-Morita–Baylis–Hillman reaction of ethyl (arylimino)acetate with methyl vinyl ketone and ethyl vinyl ketone  

Microsoft Academic Search

Aza-Morita–Baylis–Hillman (aza-MBH) reaction of ethyl (arylimino)acetate with methyl vinyl ketone and ethyl vinyl ketone has been investigated. We found that aza-MBH adducts 1 could be formed in the presence of DABCO (30mol%) and the corresponding adducts 2 could be obtained in the presence of PPh3 (30mol%) in moderate to good yields in acetonitrile under mild conditions, respectively.

Jun Gao; Guang-Ning Ma; Qing-Jiang Li; Min Shi

2006-01-01

349

Fabrication of Polymerized Crystalline Colloidal Array Thin Film Modified ?-Cyclodextrin Polymer for Paraoxon-ethyl and Parathion-ethyl Detection.  

PubMed

We have developed an optical chemical sensor for the detection of organophosphate (OP) compounds using a polymerized crystalline colloidal array (PCCA) thin film composed of a close-packed colloidal array of polystyrene particles. The PCCA thin film was modified with ?-cyclodextrin (?-CD) polymer as a capping cavity for the selective detection of paraoxon-ethyl and parathion-ethyl chemical agents. The fabrication of the modified PCCA thin film was optimized and the structure was characterized using scanning electron microscopy (SEM). The arrangement of polystyrene particles in the PCCA follows a pattern of the fcc (111) planes with strong diffraction peak in the visible spectral region and pH dependence. The diffraction peak of the ?-CD modified PCCA thin film showed a red shift according to the change of paraoxon-ethyl and parathion-ethyl concentrations at a fast response time (10 s) and high sensitivity with detection limits of 2.0 and 3.4 ppb, respectively. Furthermore, the proposed interaction mechanism of ?-CD with paraoxon-ethyl and parathion-ethyl in the ?-CD modified PCCA thin film were discussed. PMID:24813957

Bui, Minh-Phuong N; Seo, Seong S

2014-01-01

350

Cellular photo digital breathalyzer for monitoring alcohol use: a pilot study.  

PubMed

Background: Monitoring alcohol use is important in numerous situations. Direct ethanol metabolites, such as ethyl glucuronide (EtG), have been shown to be useful tools in detecting alcohol use and documenting abstinence. For very frequent or continuous control of abstinence, they lack practicability. Therefore, devices measuring ethanol itself might be of interest. This pilot study aims at elucidating the usability and accuracy of the cellular photo digital breathalyzer (CPDB) compared to self-reports in a naturalistic setting. Method: 12 social drinkers were included. Subjects used a CPDB 4 times daily, kept diaries of alcohol use and submitted urine for EtG testing over a period of 5 weeks. Results: In total, the 12 subjects reported 84 drinking episodes. 1,609 breath tests were performed and 55 urine EtG tests were collected. Of 84 drinking episodes, CPDB detected 98.8%. The compliance rate for breath testing was 96%. Of the 55 EtG tests submitted, 1 (1.8%) was positive. Conclusions: The data suggest that the CPDB device holds promise in detecting high, moderate, and low alcohol intake. It seems to have advantages compared to biomarkers and other monitoring devices. The preference for CPDB by the participants might explain the high compliance. Further studies including comparison with biomarkers and transdermal devices are needed. © 2013 S. Karger AG, Basel. PMID:24335415

Skipper, Gregory E; Thon, Natasha; Dupont, Robert L; Campbell, Michael D; Weinmann, Wolfgang; Wurst, Friedrich M

2014-01-01

351

The effect of the use of mouthwash on ethylglucuronide concentrations in urine.  

PubMed

Two studies were performed to evaluate the effect of alcohol containing mouthwash on the appearance of ethyl glucuronide (EtG) in urine. In the first study, 9 volunteers were given a 4-oz bottle of mouthwash, which contained 12% ethanol. They gargled with all 4 oz. of the mouthwash at intervals over a 15-min period. All urine samples were collected over the next 24 h. Of 39 provided urine samples, there were 20 > 50 ng/mL, 12 > 100 ng/mL, 5 > 200 ng/mL, 3 > 250 ng/mL, and 1 > 300 ng/mL. The peak concentrations were all within 12 h after the exposure. In the second study, 11 participants gargled 3 times daily for 5 days. The first morning void was collected. Sixteen of the 55 submitted samples contained EtG concentrations of greater than 50 ng/mL. All of them were less than 120 ng/mL. These studies show that incidental exposure to mouthwash containing 12% ethanol, when gargling according to the manufacturer's instructions, can result in urinary EtG values greater than 50 ng/mL. All specimens were negative for ethanol. The limits of detection and quantitation for the EtG testing were 50 ng/mL. PMID:17137525

Costantino, Anthony; Digregorio, E John; Korn, Warren; Spayd, Stephanie; Rieders, Frederic

2006-01-01

352

Urinary levels of the tobacco-specific carcinogen N?-nitrosonornicotine and its glucuronide are strongly associated with esophageal cancer risk in smokers  

PubMed Central

N?-Nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) are tobacco-specific nitrosamines. NNN and NNK can induce cancers of the esophagus and lung, respectively, in laboratory animals, but data on human esophageal cancer are lacking. The association between levels of NNN and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), an NNK metabolite, in urine samples collected before diagnosis and risk of esophageal cancer was examined in 77 patients with esophageal cancer and 223 individually matched controls, all current smokers, from a cohort of 18244 Chinese men in Shanghai, China, followed from 1986 to 2008. Urinary total NNN (free NNN plus NNN-N-glucuronide) was significantly higher, whereas the percentage of its detoxification product NNN-N-glucuronide was significantly lower in cases than controls. Odds ratios (95% confidence intervals) of esophageal cancer for the second and third tertiles of total NNN were 3.99 (1.25–12.7) and 17.0 (3.99–72.8), respectively, compared with the first tertile after adjustment for urinary total NNAL and total cotinine and smoking intensity and duration (Ptrend < 0.001). The corresponding figures for the percentage of NNN-N-glucuronides were 0.37 (0.17–0.80) and 0.27 (0.11–0.62) (Ptrend = 0.001). Urinary total NNN and the percentage of NNN-N-glucuronides almost completely accounted for the observed association for urinary total NNAL (free NNAL plus its glucuronides), urinary total cotinine and smoking intensity with esophageal cancer risk. These findings along with results of previous studies in laboratory animals support a significant and unique role of NNN in esophageal carcinogenesis in humans.

Yuan, Jian-Min; Knezevich, Aleksandar D.; Wang, Renwei; Gao, Yu-Tang; Hecht, Stephen S.; Stepanov, Irina

2011-01-01

353

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

2012-02-15

354

The Impact of Glucuronidation on the Bioactivation and DNA Adduction of the Cooked-Food Carcinogen 2-Amino-1-methyl-6-phenylimidazo[4,5-b] pyridine in vivo  

SciTech Connect

UDP-glucuronosyltransferases (UGTs) catalyze the glucuronidation of many different chemicals. Glucuronidation is especially important for detoxifying reactive intermediates from metabolic reactions, which otherwise can be biotransformed into highly reactive cytotoxic or carcinogenic species. Detoxification of certain food-borne carcinogenic heterocyclic amines (HAs) is highly dependent on UGT1A-mediated glucuronidation. 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), the most mass abundant carcinogenic HA found in well-done cooked meat, is extensively glucuronidated by UGT1A proteins. In humans, CYP1A2 catalyzed N-hydroxylation and subsequent UGT1A-mediated glucuronidation is a dominant pathway in the metabolism of PhIP. Therefore, changes in glucuronidation rates could significantly alter PhIP metabolism. To determine the importance of UGT1A-mediated glucuronidation in the biotransformation of PhIP, UGT1A proficient Wistar and UGT1A deficient Gunn rats were exposed to a single 100 {micro}g/kg oral dose of [{sup 14}C]-PhIP. Urine was collected over 24 h and the PhIP urinary metabolite profiles were compared between the two strains. After the 24 h exposure, livers and colon were removed and analyzed for DNA adduct formation by accelerator mass spectrometry. Wistar rats produced several PhIP and N-hydroxy-PhIP glucuronides that accounted for {approx}25% of the total amount of recovered urinary metabolites. In the Gunn rats, PhIP and N-hydroxy-PhIP glucuronides were reduced by 68-92%, compared to the Wistar rats, and comprised only 4% of the total amount of recovered urinary metabolites. PhIP-DNA adduct analysis from the Gunn rats revealed a correlation between reduced PhIP and N-hydroxy-PhIP glucuronide levels in the urine and increased hepatic DNA adducts, compared to the Wistar rats. These results indicate that UGT1A-mediated glucuronidation of PhIP and N-hydroxy-PhIP is an important pathway for PhIP detoxification. Failure to form glucuronide conjugates results in increases in PhIP bioactivation and DNA adduct formation, which can potentially lead to increases in tumor formation. Therefore, diminished UGT1A activity could pose a significant risk for the development of certain cancers from exposure to PhIP.

Malfatti, M A; Ubick, E A; Felton, J S

2005-03-31

355

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

356

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

2012-02-01

357

Identification and quantification of daidzein-7-glucuronide-4'-sulfate, genistein-7-glucuronide-4'-sulfate and genistein-4',7-diglucuronide as major metabolites in human plasma after administration of kinako.  

PubMed

Much attention has been paid to the metabolism and disposition of isoflavones daidzein (Dein) and genistein (Gein) with regard to the prevention of several hormone-dependent diseases. Recent studies have reported that several conjugates as well as aglycones may be biologically active or may be activated within target cells. However, the disposition of Dein and Gein in plasma is still uncertain. This paper describes the identification and quantification of the highly polar metabolites, daidzein-7-glucuronide-4'-sulfate (D-7G-4'S), genistein-7-glucuronide-4'-sulfate (G-7G-4'S), daidzein-4',7-diglucuronide (D-4',7-diG), and genistein-4',7-diglucuronide (G-4',7-diG) in human plasma after dietary administration of kinako (baked soybean powder) to two healthy volunteers. The structure identification of these conjugated metabolites in plasma was performed in comparison to the LC-ESI-MS and 600 MHz (1)H-NMR spectral data of the chemically synthesized compounds. Furthermore, 16 isoflavone metabolites including D-7G-4'S, G-7G-4'S, D-4',7-diG, and G-4',7-diG in plasma were simultaneously measured by a high-performance liquid chromatography-UV-diode-array detector method combined with solid-phase extraction using an Oasis HLB cartridge. D-7G-4'S, G-7G-4'S and G-4',7-diG were found to be major metabolites of Dein and Gein in plasma, while intact aglycones were detected to be only ca. 2% in both subjects. The findings suggest that the conjugated metabolites could be the key compounds responsible for pharmacological and medicinal properties of isoflavones. PMID:20437034

Hosoda, Kaori; Furuta, Takashi; Yokokawa, Akitomo; Ishii, Kazuo

2010-06-01

358

Is urine an alternative to cosmetically treated hair for the detection of drugs and alcohol?  

PubMed

This study attempts to assess the utility of the urine matrix as an alternative to cosmetically treated hair for the detection of drugs and alcohol for driving licence re-granting in 1026 cosmetically treated hair samples and 33 262 urine routine samples. No significant difference was observed between the percentage positive samples in cosmetically treated hair to those in urine at both the 95% and 99% significance level for amphetamines, cocaine, opiates, benzodiazepines, and methadone. Significant difference was found between the positivity rates of cannabinoids in cosmetically treated hair and that in urine indicating urine to be a better alternative to the use of the hair matrix even when cosmetically treated. The opposite was observed for the alcohol consumption marker ethyl glucuronide (EtG) for which the positivity rate in cosmetically treated hair was twice that in urine samples. Particularly for alcohol abstinence monitoring, as for the rehabilitative driving licence re-granting medical and psychological assessment (MPA) programme in Germany, it seems that ethyl glucuronide (EtG) in hair presents a much better alternative than urine testing, even when cosmetically treated hair is analyzed. Moreover, segmentation is an additional advantage of hair testing which can provide additional useful information. PMID:24817057

Agius, Ronald; Dufaux, Bertin; Kahl, Hans-Gerhard; Nadulski, Thomas

2014-06-01

359

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

360

Patterns of free (unconjugated) buprenorphine, norbuprenorphine, and their glucuronides in urine using liquid chromatography-tandem mass spectrometry.  

PubMed

Patterns of buprenorphine and metabolites were examined in 1946 positive urine samples analyzed by liquid chromatography-tandem mass spectrometry for free (unconjugated) buprenorphine and norbuprenorphine (quantitative, 2 to 1000 ng/mL) and buprenorphine-glucuronide (B3G) and norbuprenorphine-glucuronide (N3G) (semi-quantitative, 5 to 1000 ng/mL). Two distribution patterns predominated with 49.1% positive for norbuprenorphine, B3G, and N3G and 41.6% positive for buprenorphine, norbuprenorphine, B3G, and N3G. Buprenorphine, positive in 45.5% of samples, was mostly < 5 ng/mL (median 6.1 ng/mL), but 9.8% were > 1000 ng/mL. Norbuprenorphine, B3G, and N3G had semi-Gaussian distributions with medians of 64.7, 108, and 432 ng/mL, respectively. With buprenorphine < 100 ng/mL (767 samples) or ? 100 ng/mL (19 quantifiable samples), the respective median metabolic ratios (free norbuprenorphine/free buprenorphine) were 25.0 and 0.15. In 12 retested "> 1000 ng/mL" buprenorphine samples, free buprenorphine was 4160 to 39,400 ng/mL and free naloxone 2140 to 9560 ng/mL. In 87 subsequent samples with buprenorphine < 20 ng/mL, naloxone concentrations were < 50 ng/mL. Concentrations of buprenorphine > 100 ng/mL (particularly with low metabolite concentrations) are suspect of urine adulteration with medication (4% in the database) that can be checked in most cases by concurrent analysis for naloxone. PMID:22337776

McMillin, Gwendolyn A; Davis, Rebecka; Carlisle, Heidi; Clark, Chantry; Marin, Stephanie J; Moody, David E

2012-03-01

361

Meconium Indicators of Maternal Alcohol Abuse during Pregnancy and Association with Patient Characteristics.  

PubMed

Aim. Identification of women with moderate alcohol abuse during pregnancy is difficult. We correlated self-reported alcohol consumption during pregnancy and patient characteristics with objective alcohol indicators measured in fetal meconium. Methods. A total of 557 women singleton births and available psychological tests, obstetric data and meconium samples were included in statistical analysis. Alcohol metabolites (fatty acid ethyl esters (FAEEs) and ethyl glucuronide (EtG)), were determined from meconium and correlated with patient characteristics. Results. We found that 21.2% of the 557 participants admitted low-to-moderate alcohol consumption during pregnancy. Of the parameters analyzed from meconium, only EtG showed an association with alcohol history (P < 0.01). This association was inverse in cases with EtG value above 120?ng/g. These values indicate women with most severe alcohol consumption, who obviously denied having consumed alcohol during pregnancy. No other associations between socioeconomic or psychological characteristics and the drinking status (via meconium alcohol metabolites) could be found. Conclusion. Women who drink higher doses of ethanol during pregnancy, according to metabolite measures in meconium, might be less likely to admit alcohol consumption. No profile of socioeconomic or psychological characteristics of those women positively tested via meconium could be established. PMID:24800249

Goecke, Tamme W; Burger, Pascal; Fasching, Peter A; Bakdash, Abdulsallam; Engel, Anne; Häberle, Lothar; Voigt, Franziska; Faschingbauer, Florian; Raabe, Eva; Maass, Nicolai; Rothe, Michael; Beckmann, Matthias W; Pragst, Fritz; Kornhuber, Johannes

2014-01-01

362

Meconium Indicators of Maternal Alcohol Abuse during Pregnancy and Association with Patient Characteristics  

PubMed Central

Aim. Identification of women with moderate alcohol abuse during pregnancy is difficult. We correlated self-reported alcohol consumption during pregnancy and patient characteristics with objective alcohol indicators measured in fetal meconium. Methods. A total of 557 women singleton births and available psychological tests, obstetric data and meconium samples were included in statistical analysis. Alcohol metabolites (fatty acid ethyl esters (FAEEs) and ethyl glucuronide (EtG)), were determined from meconium and correlated with patient characteristics. Results. We found that 21.2% of the 557 participants admitted low-to-moderate alcohol consumption during pregnancy. Of the parameters analyzed from meconium, only EtG showed an association with alcohol history (P < 0.01). This association was inverse in cases with EtG value above 120?ng/g. These values indicate women with most severe alcohol consumption, who obviously denied having consumed alcohol during pregnancy. No other associations between socioeconomic or psychological characteristics and the drinking status (via meconium alcohol metabolites) could be found. Conclusion. Women who drink higher doses of ethanol during pregnancy, according to metabolite measures in meconium, might be less likely to admit alcohol consumption. No profile of socioeconomic or psychological characteristics of those women positively tested via meconium could be established.

Goecke, Tamme W.; Burger, Pascal; Fasching, Peter A.; Bakdash, Abdulsallam; Engel, Anne; Haberle, Lothar; Voigt, Franziska; Faschingbauer, Florian; Raabe, Eva; Maass, Nicolai; Rothe, Michael; Beckmann, Matthias W.; Pragst, Fritz

2014-01-01

363

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

2013-03-18

364

Enantiomer selective glucuronidation of the non-steroidal pure anti-androgen bicalutamide by human liver and kidney: role of the human UDP-glucuronosyltransferase (UGT)1A9 enzyme  

PubMed Central

Bicalutamide (Casodex®) is a non-steroidal pure anti-androgen used in the treatment of localized prostate cancer. It is a racemate drug and its activity resides in the (R)-enantiomer, with little in the (S)-enantiomer. A major metabolic pathway for bicalutamide is glucuronidation catalyzed by UDP-glucuronosyltransferase (UGT) enzymes. While (S)bicalutamide is directly glucuronidated, (R)bicalutamide requires hydroxylation prior to glucuronidation. The contribution of human tissues and UGT isoforms in the metabolism of these enantiomers has not been extensively investigated. In this study, both (R) and/or (S)bicalutamide were converted into glucuronide (-G) derivatives following incubation of pure and racemic solutions with microsomal extracts from human liver and kidney. Intestinal microsomes exhibited only low reactivity with these substrates. Km values of liver and kidney samples for (S)bicalutamide glucuronidation were similar, and lower than values obtained with the (R)-enantiomer. Among the 16 human UGTs tested, UGT1A8 and UGT1A9 were able to form both (S) and (R)bicalutamide-G from pure or racemic substrates. UGT2B7 was also able to form (R)bicalutamide-G. Kinetic parameters of the recombinant UGT2B7, UGT1A8 and UGT1A9 enzymes support a predominant role of the UGT1A9 isoform in bicalutamide metabolism. Accordingly, (S)bicalutamide inhibited the ability of human liver and kidney microsomes to glucuronidate the UGT1A9 probe substrate, propofol. In conclusion, the present study provides the first comprehensive analysis of in vitro bicalutamide glucuronidation by human tissues and UGTs, and identifies UGT1A9 as a major contributor for (R) and (S) glucuronidation in the human liver and kidney.

Grosse, Laurent; Campeau, Anne-Sophie; Caron, Sarah; Morin, Frederic-Alexandre; Meunier, Kim; Trottier, Jocelyn; Caron, Patrick; Verreault, Melanie; Barbier, Olivier

2013-01-01

365

Enantiomer selective glucuronidation of the non-steroidal pure anti-androgen bicalutamide by human liver and kidney: role of the human UDP-glucuronosyltransferase (UGT)1A9 enzyme.  

PubMed

Bicalutamide (Casodex(®) ) is a non-steroidal pure anti-androgen used in the treatment of localized prostate cancer. It is a racemate drug, and its activity resides in the (R)-enantiomer, with little in the (S)-enantiomer. A major metabolic pathway for bicalutamide is glucuronidation catalysed by UDP-glucuronosyltransferase (UGT) enzymes. While (S)bicalutamide is directly glucuronidated, (R)bicalutamide requires hydroxylation prior to glucuronidation. The contribution of human tissues and UGT isoforms in the metabolism of these enantiomers has not been extensively investigated. In this study, both (R) and/or (S)bicalutamide were converted into glucuronide (-G) derivatives after incubation of pure and racemic solutions with microsomal extracts from human liver and kidney. Intestinal microsomes exhibited only low reactivity with these substrates. Km values of liver and kidney samples for (S)bicalutamide glucuronidation were similar, and lower than values obtained with the (R)-enantiomer. Among the 16 human UGTs tested, UGT1A8 and UGT1A9 were able to form both (S) and (R)bicalutamide-G from pure or racemic substrates. UGT2B7 was also able to form (R)bicalutamide-G. Kinetic parameters of the recombinant UGT2B7, UGT1A8 and UGT1A9 enzymes support a predominant role of the UGT1A9 isoform in bicalutamide metabolism. Accordingly, (S)bicalutamide inhibited the ability of human liver and kidney microsomes to glucuronidate the UGT1A9 probe substrate, propofol. In conclusion, the present study provides the first comprehensive analysis of in vitro bicalutamide glucuronidation by human tissues and UGTs and identifies UGT1A9 as a major contributor for (R) and (S) glucuronidation in the human liver and kidney. PMID:23527766

Grosse, Laurent; Campeau, Anne-Sophie; Caron, Sarah; Morin, Frédéric-Alexandre; Meunier, Kim; Trottier, Jocelyn; Caron, Patrick; Verreault, Mélanie; Barbier, Olivier

2013-08-01

366

Three-Dimensional Quantitative Structure-Activity Relationship Studies on UGT1A9-Mediated 3-O-Glucuronidation of Natural Flavonols Using a Pharmacophore-Based Comparative Molecular Field Analysis ModelS?  

PubMed Central

Glucuronidation is often recognized as one of the rate-determining factors that limit the bioavailability of flavonols. Hence, design and synthesis of more bioavailable flavonols would benefit from the establishment of predictive models of glucuronidation using kinetic parameters [e.g., Km, Vmax, intrinsic clearance (CLint) = Vmax/Km] derived for flavonols. This article aims to construct position (3-OH)-specific comparative molecular field analysis (CoMFA) models to describe UDP-glucuronosyltransferase (UGT) 1A9-mediated glucuronidation of flavonols, which can be used to design poor UGT1A9 substrates. The kinetics of recombinant UGT1A9-mediated 3-O-glucuronidation of 30 flavonols was characterized, and kinetic parameters (Km, Vmax, CLint) were obtained. The observed Km, Vmax, and CLint values of 3-O-glucuronidation ranged from 0.04 to 0.68 ?M, 0.04 to 12.95 nmol/mg/min, and 0.06 to 109.60 ml/mg/min, respectively. To model UGT1A9-mediated glucuronidation, 30 flavonols were split into the training (23 compounds) and test (7 compounds) sets. These flavonols were then aligned by mapping the flavonols to specific common feature pharmacophores, which were used to construct CoMFA models of Vmax and CLint, respectively. The derived CoMFA models possessed good internal and external consistency and showed statistical significance and substantive predictive abilities (Vmax model: q2 = 0.738, r2 = 0.976, rpred2 = 0.735; CLint model: q2 = 0.561, r2 = 0.938, rpred2 = 0.630). The contour maps derived from CoMFA modeling clearly indicate structural characteristics associated with rapid or slow 3-O-glucuronidation. In conclusion, the approach of coupling CoMFA analysis with a pharmacophore-based structural alignment is viable for constructing a predictive model for regiospecific glucuronidation rates of flavonols by UGT1A9.

Wu, Baojian; Morrow, John Kenneth; Singh, Rashim; Zhang, Shuxing

2011-01-01

367

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

368

An in vitro experiment on the interaction of charcoal or wheat bran with 11-nor-9-carboxy-?(9)-tetrahydrocannabinol and its glucuronide.  

PubMed

The rather long yet variable terminal half-lives and detection times since last use of urinary cannabinoids may partly be attributed to their enterohepatic circulation which generally can be interrupted or restricted by chemical adsorbents. Therefore, an in vitro experiment was performed to study the adsorption/binding of 11-nor-9-carboxy-?9-tetrahydrocannabinol (THC-COOH) and its glucuronide to activated charcoal and wheat bran; remaining concentrations were determined by liquid chromatography/tandem mass spectrometry. Adsorption/binding of 1,000 ng/mL of free or conjugated THC-COOH was complete using as little as 5 mg of charcoal whereas adsorption/binding to wheat bran increased with increasing amounts. Taking of remedies affecting enterohepatic recycling of THC-COOH and its glucuronide may challenge interpretation of cannabinoid concentrations used to detect or assess frequency of drug use or the time since last drug consumption. PMID:24077855

Skopp, Gisela; Mikus, Gerd

2013-11-01

369

40 CFR 721.10243 - Phosphonic acid, P-[2-[bis(2-hydroxyethyl)amino]ethyl]-, bis(2-chloroethyl) ester.  

Code of Federal Regulations, 2013 CFR

...false Phosphonic acid, P-[2-[bis(2-hydroxyethyl)amino]ethyl]-, bis...10243 Phosphonic acid, P-[2-[bis(2-hydroxyethyl)amino]ethyl]-, bis...identified as phosphonic acid, P-[2-[bis(2-hydroxyethyl)amino]ethyl]-,...

2013-07-01

370

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

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...

2010-07-01

372

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

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...

2010-07-01

374

Glucuronidation of Lipophilic Substrates: Preparation of 3-Benzo[a]pyrenyl-?-D-glucopyranosiduronic Acid in Multimilligram Quantities by Microsomal UDP-Glucuronyl Transferase  

Microsoft Academic Search

convenient method for the enzyraic conversion of multimilli-gram quantities of 3-hydroxybenzo[a]pyrene to 3-benzo[a]pyrenyl-?-D-glucopyranosiduronic acid in 90% yield is described. Commer-cially available freeze-dried rabbit liver microsomes were incubated in the presence of UDPGA, 3-hydroxybenzo[a]pyrene, and Triton X-100 detergent (Figure 1). The course of the biosynthetic reaction was followed by fluorimetry. The glucuronide product was extracted from the acidified incubation supernate with

David B. Johnson; Melvin J. Swanson; Charles W. Barker; Cindy B. Fansk; Evelyn E. Murrill

1979-01-01

375

BIOMARKERS TO DISCLOSE RECENT INTAKE OF ALCOHOL: POTENTIAL OF 5-HYDROXYTRYPTOPHOL GLUCURONIDE TESTING USING NEW DIRECT UPLC-TANDEM MS AND ELISA METHODS  

Microsoft Academic Search

Aims: This study compared two new methods for direct determination of 5-hydroxytryptophol glucuronide (GTOL) in urine, a biomarker for detection of recent alcohol consumption. Methods: Urine samples were collected from ten alcoholic patients during recovery from intoxication. A direct injection ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS\\/MS) method for measurement of the urinary GTOL to 5-hydroxyindoleacetic acid (5-HIAA) ratio, and an

OLOF BECK; NIKOLAI STEPHANSON; NORBERT DAHMEN

2007-01-01

376

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

377

Effects of ethyl alcohol on behaviour in nursing female mice  

Microsoft Academic Search

Effects of administering 10% ethyl alcohol as drinking fluid to mice during pregnancy and lactation have been examined by ethological analysis of behaviour of nursing females in their home cages at 1 day, 5–7 days and 12–14 days postpartum. The treatment with alcohol did not affect gestation period or litter size, and fluid intake of treated mice remained similar to

Franzeska G. Ewart; Margaret G. Cutler

1979-01-01

378

Enantioselective Metabolism of Quizalofop-Ethyl in Rat  

PubMed Central

The pharmacokinetic and distribution of the enantiomers of quizalofop-ethyl and its metabolite quizalofop-acid were studied in Sprague-Dawley male rats. The two pairs of enantiomers were determined using a validated chiral high-performance liquid chromatography method. Animals were administered quizalofop-ethyl at 10 mg kg?1 orally and intravenously. It was found high concentration of quizalofop-acid in the blood and tissues by both intragastric and intravenous administration, and quizalofop-ethyl could not be detected through the whole study which indicated a quick metabolism of quizalofop-ethyl to quizalofop-acid in vivo. In almost all the samples, the concentrations of (+)-quizalofop-acid exceeded those of (?)-quizalofop-acid. Quizalofop-acid could still be detected in the samples even at 120 h except in brain due to the function of blood-brain barrier. Based on a rough calculation, about 8.77% and 2.16% of quizalofop-acid were excreted through urine and feces after intragastric administration. The oral bioavailability of (+)-quizalofop-acid and (?)-quizalofop-acid were 72.8% and 83.6%.

Liang, Yiran; Wang, Peng; Liu, Donghui; Shen, Zhigang; Liu, Hui; Jia, Zhixin; Zhou, Zhiqiang

2014-01-01

379

Ethyl-enedi-ammonium chloride thio-cyanate  

PubMed Central

In the ethyl­enedi­ammonium dication of the title salt, C2H10N2 2+·Cl?·SCN?, the N—C—C—N torsion angle is 72.09?(12)°. In the crystal, an extensive three-dimensional hydrogen-bonding network, formed by N—H?Cl and N—H?N hydrogen bonds, holds all the ions together.

Karoui, Sahel; Kamoun, Slaheddine; Michaud, Francois

2013-01-01

380

Diffusion of propionic acid ethyl ester (1); air (2)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume A `Gases in Gases, Liquids and their Mixtures' of Volume 15 `Diffusion in Gases, Liquids and Electrolytes' of Landolt-Börnstein Group IV `Physical Chemistry'. It is part of the chapter of the chapter `Diffusion in Pure Gases' and contains data on diffusion of (1) propionic acid ethyl ester; (2) air

Winkelmann, J.

381

HEALTH AND ENVIRONMENTAL EFFECTS PROFILE FOR METHYL ETHYL KETONE  

EPA Science Inventory

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 hazardo...

382

EVALUATION OF THE POTENTIAL CARCINOGENICITY OF ETHYL METHANESULFONATE  

EPA Science Inventory

Ethyl methanesulfonate is a probable human carcinogen, classified as weight-of-evidence Group B2 under the EPA Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1986a). vidence on potential carcinogenicity from animal studies is sufficient,o and the evidence from human studies...

383

HEALTH AND ENVIRONMENTAL EFFECTS PROFILE FOR METHYL ETHYL BENZENES  

EPA Science Inventory

The Health and Environmental Effects Profile for Methyl Ethyl Benzenes was prepared by the Office of Health and Environmental Assessment, Environmental Criteria and Assessment Office, Cincinnati, OH for the Office of Solid Waste to support listings of hazardous constituents of a ...

384

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

385

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

386

The Slow Oxidation of Gaseous Methyl Ethyl Ketone  

Microsoft Academic Search

The kinetics of the reaction between oxygen and gaseous methyl ethyl ketone (butanone) have been investigated in the range 250 to 450 degrees C. The anomalous temperature coefficient of the rate offers a good example of the transition from a low-temperature mode of oxidation to a high-temperature mode. Similar behaviour has been observed with hydrocarbons and is ascribable to the

J. Bardwell; Cyril Hinshelwood

1950-01-01

387

EVALUATION OF THE POTENTIAL CARCINOGENICITY OF ETHYL CARBAMATE (URETHANE)  

EPA Science Inventory

Ethyl carbamate is a probable human carcinogen, classified as weight-of-evidence Group B2 under the EPA Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1986a). Evidence on potential carcinogenicity from animal studies is "Sufficient," and the evidence from human studies is "...

388

Walk-Through Survey at Ethyl Corporation, Pasadena, Texas.  

National Technical Information Service (NTIS)

Worker exposure to vinyl-chloride (75014) (VC) were determined at the Ethyl Corporation (SIC-2824) in Pasadena, Texas on May 9, 1974. The survey was part of a NIOSH study of the health effects of occupational exposure to VC. Twenty workers were directly i...

J. H. Jones P. J. Bierbaum

1974-01-01

389

40 CFR 180.430 - Fenoxaprop-ethyl; tolerances for residues.  

Code of Federal Regulations, 2013 CFR

...herbicide fenoxaprop-ethyl, including its metabolites and degradates, in or on the commodities...oxy]phenoxy]propanoate, and its metabolites, 2-[4-[(6-chloro-2-benzoxazolyl...herbicide fenoxaprop-ethyl, including its metabolites and degradates, in or...

2013-07-01

390

40 CFR 180.212 - S-Ethyl cyclohexylethylthio-carbamate; tolerances for residues.  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 false S-Ethyl cyclohexylethylthio-carbamate; tolerances for residues. 180.212 Section 180.212...Tolerances § 180.212 S -Ethyl cyclohexylethylthio-carbamate; tolerances for residues. (a) General....

2010-07-01

391

40 CFR 180.212 - S-Ethyl cyclohexylethylthio-carbamate; tolerances for residues.  

Code of Federal Regulations, 2010 CFR

... 2009-07-01 false S-Ethyl cyclohexylethylthio-carbamate; tolerances for residues. 180.212 Section 180.212...Tolerances § 180.212 S -Ethyl cyclohexylethylthio-carbamate; tolerances for residues. (a) General....

2009-07-01

392

40 CFR 180.212 - S-Ethyl cyclohexylethylthio-carbamate; tolerances for residues.  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 false S-Ethyl cyclohexylethylthio-carbamate; tolerances for residues. 180.212 Section 180.212...Tolerances § 180.212 S -Ethyl cyclohexylethylthio-carbamate; tolerances for residues. (a) General....

2013-07-01

393

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

394

Determination of Serotonin and Dopamine Metabolites in Human Brain Microdialysis and Cerebrospinal Fluid Samples by UPLC-MS/MS: Discovery of Intact Glucuronide and Sulfate Conjugates  

PubMed Central

An UPLC-MS/MS method was developed for the determination of serotonin (5-HT), dopamine (DA), their phase I metabolites 5-HIAA, DOPAC and HVA, and their sulfate and glucuronide conjugates in human brain microdialysis samples obtained from two patients with acute brain injuries, ventricular cerebrospinal fluid (CSF) samples obtained from four patients with obstructive hydrocephalus, and a lumbar CSF sample pooled mainly from patients undergoing spinal anesthesia in preparation for orthopedic surgery. The method was validated by determining the limits of detection and quantification, linearity, repeatability and specificity. The direct method enabled the analysis of the intact phase II metabolites of 5-HT and DA, without hydrolysis of the conjugates. The method also enabled the analysis of the regioisomers of the conjugates, and several intact glucuronide and sulfate conjugates were identified and quantified for the first time in the human brain microdialysis and CSF samples. We were able to show the presence of 5-HIAA sulfate, and that dopamine-3-O-sulfate predominates over dopamine-4-O-sulfate in the human brain. The quantitative results suggest that sulfonation is a more important phase II metabolism pathway than glucuronidation in the human brain.

Suominen, Tina; Uutela, Paivi; Ketola, Raimo A.; Bergquist, Jonas; Hillered, Lars; Finel, Moshe; Zhang, Hongbo; Laakso, Aki; Kostiainen, Risto

2013-01-01

395

Impact of structural differences on the in vitro glucuronidation kinetics of potentially dopaminergic hydroxy-2-aminotetralins and naphthoxazines using rat and human liver microsomes.  

PubMed

The in vitro glucuronidation of seven monohydroxy-2-aminotetralins and two naphthoxazines has been determined using human and rat liver microsomes. All these compounds stimulate the D2 dopamine receptor. The influence of the position of the phenolic hydroxyl group was studied with rat microsomes in monohydroxy-2-(N,N-dipropylamino)-tretralins. The highest activity and intrinsic clearance was found for 7-OH-DPAT, but the latter values for 5-OH-DPAT and 6-OH-DPAT were much lower by a factor of 9 and 30, respectively. The 8-OH-isomer was not glucuronidated at all. Substitution of a propyl side chain by a thienylethyl-, or phenylethyl side chain, in 5-hydroxy-DPAT, or in (+)-4-propyl-9-hydroxyhexahydronaphthoxazine (PHNO, N-0500), showed a large increase of the UDPGT affinity and intrinsic clearance especially for N-0437. It also resulted for N-0437 in a much higher affinity towards the dopaminergic D2 receptor. Although the glucuronidation activity of human microsomes was found to be considerably lower than that of rat microsomes, the latter phenomenon was clearly visible with human microsomes as well. These findings may have serious implications for the ability of these drugs to adequately reach the brain. PMID:1676161

Swart, P J; Jansman, F G; Drenth, B F; de Zeeuw, R A; Dijkstra, D; Horn, A S

1991-03-01

396

Protein quantification of UDP-glucuronosyltransferases 1A1 and 2B7 in human liver microsomes by LC-MS/MS and correlation with glucuronidation activities.  

PubMed

The aims of this study were to quantify absolute protein levels of uridine 5'-diphosphate-glucuronosyltransferases (UGTs) 1A1 and 2B7 in human liver microsomes (HLMs) and to investigate their correlation with marker activities. A quantification method for UGT1A1 and UGT2B7 in HLMs was developed. Unique tryptic peptides of UGT1A1 and UGT2B7 in tryptically digested HLMs were simultaneously quantified by liquid chromatography (LC) equipped with tandem mass spectrometry (MS) using corresponding stable isotope-labelled peptides as internal standards. Bovine serum albumin was used as a blank matrix for calibration curve samples. Our procedure had good digestion efficiency, sensitivity, calibration curve linearity, and reproducibility of digestion to quantification. In 16 individual HLMs, the protein levels of UGT1A1 and UGT2B7 ranged from 6.50 to 44.6 pmol/mg and 4.45 to 18.2 pmol/mg, respectively. Estradiol 3?-glucuronidation correlated strongly with the UGT1A1 level, indicating its high reliability as a reaction marker. Both morphine 3-O- and 6-O-glucuronidation significantly correlated with UGT2B7 level. However, the intercept of the linear regression clearly indicates that morphine glucuronidation was mediated by other UGT isoforms in addition to UGT2B7. PMID:22435749

Sato, Yuichiro; Nagata, Masanori; Kawamura, Akio; Miyashita, Aiji; Usui, Takashi

2012-09-01

397

Accurate Prediction of Glucuronidation of Structurally Diverse Phenolics by Human UGT1A9 Using Combined Experimental and In Silico Approaches  

PubMed Central

Purpose The catalytic selectivity of human UGT1A9, an important membrane-bound enzyme catalyzing glucuronidation of xenobiotics were determined experimentally using 145 phenolics, and analyzed by 3D-QSAR methods. Methods The catalytic efficiency of UGT1A9 was determined by kinetic profiling. Quantitative structure activity relationships were analyzed using the CoMFA and CoMSIA techniques. Molecular alignment of the substrate structures was made by superimposing the glucuronidation site and its adjacent aromatic ring to achieve maximal steric overlap. For a substrate with multiple active glucuronidation sites, each site was considered as a separate substrate. Results The 3D-QSAR analyses produced statistically reliable models with good predictive power (CoMFA: q2 = 0.548, r2= 0.949, r2pred = 0.775; CoMSIA: q2 = 0.579, r2= 0.876, r2pred = 0.700). The contour coefficient maps were applied to elucidate structural features among substrates that are responsible for the selectivity differences. Furthermore, the contour coefficient maps were overlaid in the catalytic pocket of a homology model of UGT1A9; this enabled us to identify the UGT1A9 catalytic pocket with a high degree of confidence. Conclusion The CoMFA/CoMSIA models can predict the substrate selectivity and in vitro clearance of UGT1A9. Our findings also provide a possible molecular basis for understanding UGT1A9 functions and its substrate selectivity.

Wu, Baojian; Wang, Xiaoqiang; Zhang, Shuxing; Hu, Ming

2012-01-01

398

Simultaneous determination of three glucuronide conjugates of scutellarein in rat plasma by LC-MS/MS for pharmacokinetic study of breviscapine.  

PubMed

A selective and sensitive LC-MS/MS method was developed and validated for simultaneous determination of three glucuronide conjugates of scutellarein in rat plasma. Plasma samples were pretreated by protein precipitation with acetonitrile. The analytes (scutellarin, scutellarein-6,7-di-O-?-d-glucuronide and scutellarein-6-O-?-d-glucuronide), together with internal standard (IS, baicalin) were separated on a Diamonsil C18 column (150mm×4.6mm, 5?m) with an isocratic mobile phase consisting of methanol-water-formic acid (55:45:0.2, v/v/v). Mass spectrometric detection was performed by selected reaction monitoring (SRM) mode via electrospray ionization source operating in negative ionization mode. The method was linear for all the analytes over the investigated concentration ranges with correlation coefficients greater than 0.9954. The intra- and inter-day precisions were less than 9.1% and the relative error was between -1.7% and 4.2%. The extraction recoveries of the analytes and IS from rat plasma were over 63%. The validated method has been successfully applied to a pharmacokinetic study of breviscapine in rats after intragastric administration at a dose of 20mg/kg. The pharmacokinetic results would be helpful to better understand the pharmacological actions of breviscapine. PMID:24999248

Wang, Xin; Xia, Hongjun; Liu, Youping; Qiu, Feng; Di, Xin

2014-08-15

399

Quantification of phenolic acids and their methylates, glucuronides, sulfates and lactones metabolites in human plasma by LC-MS/MS after oral ingestion of soluble coffee.  

PubMed

Chlorogenic acids and derivatives like phenolic acids are potentially bioactive phenolics, which are commonly found in many foods. Once absorbed, chlorogenic and phenolic acids are highly metabolized by the intestine and the liver, producing glucuronidated and/or sulphated compounds. These metabolites were analyzed in human plasma using a validated liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method. After protein precipitation, phenolic acids and their metabolites were extracted by using ethanol and chromatographic separation was achieved by reversed-phase using an Acquity UPLC BEH C18 column combined with a gradient elution system using 1% acetic acid aqueous solution and 1% acetic acid with 100% acetonitrile. The method was able to quantify 56 different compounds including 24 phenolic acids, 4 lactones, 15 sulfates and 13 glucuronides metabolites between 5 and 1000nM in plasma for most of them, except for m-dihydrocoumaric acid, 5-ferulloylquinic-glucuronide, 4-methoxycinnamic acid, 3-phenylpropionic acid, 3-(4-methoxyphenyl)propionic acid (25 to 1000nM) and p-dihydrocoumaric acid (50-1000nM). Values of repeatability and intermediate reproducibility were below 15% of deviation in general, and maximum 20% for the lowest concentrations. The validated method was successfully applied to quantify phenolic acids and their metabolites in plasma obtained after oral ingestion of soluble coffee. In conclusion, the developed and validated method is proved to be very sensitive, accurate and precise for the quantification of these possible dietary phenols. PMID:24216280

Marmet, Cynthia; Actis-Goretta, Lucas; Renouf, Mathieu; Giuffrida, Francesca

2014-01-01

400

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

401

Comparison of surface structures of poly(ethyl methacrylate) and poly(ethyl acrylate) in different chemical environments.  

PubMed

Sum frequency generation (SFG) vibrational spectroscopy has been applied to investigate and compare the chemical structures of poly(ethyl methacrylate) (PEMA) and poly(ethyl acrylate) (PEA) in air, in water, and in a non-polar solvent, FC-75. SFG spectra from both polymer surfaces in air are dominated by vibrational modes from the ester ethyl side groups. The average orientation of these ester ethyl groups on the two polymer surfaces is slightly different. In water, the two polymers show markedly different restructuring behavior. The ester ethyl side chains on the PEMA surface in water reorient to tilt more toward the surface, yet remain ordered. Such a restructuring of the PEMA surface in water is reversible. However, no SFG signal was detected from the PEA/water interface, showing that the surface of PEA becomes disordered upon contacting water, and this process is irreversible. SFG results collected from the C=O range indicate that hydrogen bonding is observed for both polymer/water interfaces, but the order of C=O at the PEA/water interface is much lower than that at the PEMA/water interface. Supplemental experiments support our hypothesis that the PEA surface becomes rough and loses order gradually as it interacts with water. We have demonstrated, for the first time, that the loss of surface structural order is due to the interaction between soft PEA chains with water molecules followed by reorganization of the polymer backbone. This causes the polymer surface to become rough and disordered. However, the surface structures of PEMA and PEA in FC-75 are similar and are also similar to those in air. This indicates that not only T(g), but also the contacting medium plays an important role in determining the surface restructuring behavior of polymer materials. PMID:19785122

Chen, Chunyan; Clarke, Matthew L; Wang, Jie; Chen, Zhan

2005-06-01

402

A Nonlinear Mixed Effects Pharmacokinetic Model for Dapagliflozin and Dapagliflozin 3-O-glucuronide in Renal or Hepatic Impairment  

PubMed Central

Dapagliflozin is a sodium–glucose co-transporter 2 inhibitor in development for the treatment of type 2 diabetes mellitus. A semi-mechanistic population pharmacokinetic (PK) model was developed for dapagliflozin and its inactive metabolite dapagliflozin 3-O-glucuronide (D3OG) with emphasis on renal and hepatic contribution to dapagliflozin metabolism. Renal and hepatic impairment decreased the clearance of dapagliflozin to D3OG and the clearance of D3OG. The fraction of D3OG formed via the renal route decreased from 40–55% in subjects with normal renal function (creatinine clearance (CLcr) > 80?ml/min) to 10% in subjects with severe renal insufficiency (CLcr = 13?ml/min). The model-based simulations suggested that the increase of systemic exposure (AUCss) of dapagliflozin and D3OG was less than twofold in subjects with mild or moderate renal impairment. This population modeling analysis presents a useful approach to evaluate the impact of renal and hepatic function on the PK of dapagliflozin.

van der Walt, J-S; Hong, Y; Zhang, L; Pfister, M; Boulton, D W; Karlsson, M O

2013-01-01

403

Elevation of retinyl ester level in the lungs of rats following repeated intraperitoneal injections of retinoic acid or retinoyl glucuronide.  

PubMed

Retinoic acid (RA) is involved in the development of both the conducting airway and alveolar portions of the lung. RA plays a key role in the induction of the formation of alveolar septa. Retinoyl beta-glucuronide (RAG), an endogenous retinoid, acts like RA, but is much less cytotoxic. We examined the effect of daily intraperitoneal doses of RA and RAG (1.66 micromol/kg) in dimethyl sulfoxide (DMSO) and cotton seed oil on the stores of retinol and retinyl ester (RE) in the lung of rats. In two separate experiments, one involving normal rats, and the other involving elastase-treated rats, there was up to a 9-fold increase in REs content in the lungs of rats that received RA or RAG for 12 days as compared to Control rats. The accumulation was most profound when RA was injected in DMSO and least when RAG was injected in cotton seed oil. The reason for the accumulation of REs in the lung is not clearly known. PMID:15123219

Barua, Arun B; McGowan, Stephen E; Ivanoff, Kristi D; Goswami, Bhabesh C; Olson, James A

2004-01-01

404

Direct monitoring of enzyme reactions using micellar electrokinetic capillary chromatography. Optimisation of drug glucuronide and sulfate conjugate hydrolysis.  

PubMed

This paper demonstrates the use of micellar electrokinetic capillary chromatography (MECC) to monitor enzyme reaction conditions. The hydrolysis reactions of model conjugated substrates (morphine and reduced flunixin glucuronides, napthyl sulfate), by proprietary beta-glucuronidase preparations, were studied under varied experimental conditions. Reactions were carried out in autosampler vials with incubation in a thermostatted CE autosampler tray. MECC was performed using borax buffer (17.5 mM, pH 9.3) modified with sodium dodecyl sulfate (70 mM). Repetitive injections were made from the sample vial throughout the course of the reactions at a frequency of up to 10 h-1. MECC provided a rapid and reproducible assay for the model substrates. Baseline interference from the enzymes prevented measurement of product increase, therefore substrate decrease was measured from the peak areas. Monitoring of reactions in this way has proved valuable in the optimisation of hydrolysis conditions used in sample preparation for drug analysis. beta-Glucuronidase preparations from Helix pomatia were found to give the best performance of those evaluated in terms of deconjugation efficiency. PMID:9175276

Taylor, M R; Westwood, S A; Perrett, D

1997-04-18

405

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

406

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

407

C-Fos activation in the periaqueductal gray following acute morphine-3?-D-glucuronide or morphine administration.  

PubMed

Morphine-3?-D-glucuronide (M3G), a primary morphine metabolite, evokes hyperalgesia in mice and rats and putatively mediates hyperalgesia associated with morphine (MOR) administration. However, M3G does not act via opioid receptors and its locus of activity in the CNS is unknown. Here we assessed the density of neurons immunoreactive for c-Fos, an immediate early gene regulated by neuronal activity, in the periaqueductal gray (PAG), a midbrain region critical to pain modulation, in male CD-1 mice after MOR and M3G exposure. Mice were injected with acute doses of MOR or M3G following a pre-injection of saline (SAL) or the opioid antagonist naltrexone (NTX), perfused 3 h later, and labeled for c-Fos using immunohistochemistry. Labeled image stacks taken from the PAG were then analyzed on a confocal microscope for the number of neurons showing c-Fos expression. Relative to controls, significant but similar increases in the mean density of PAG c-Fos immunoreactive neurons were observed in mice pre-injected with SAL then M3G or morphine. However, NTX pre-injection blocked this increase in MOR but not M3G injected mice. The data demonstrate for the first time a CNS locus for M3G activity. Consistent with previous observations, this M3G activity is not mediated by opioid receptors. PMID:24631297

Arout, Caroline A; Caldwell, Megan; McCloskey, Daniel P; Kest, Benjamin

2014-05-10

408

In vivo-formed versus preformed metabolite kinetics of trans-resveratrol-3-sulfate and trans-resveratrol-3-glucuronide.  

PubMed

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. PMID:22807110

Sharan, Satish; Iwuchukwu, Otito F; Canney, Daniel J; Zimmerman, Cheryl L; Nagar, Swati

2012-10-01

409

Analysis of 11-nor-?9 -tetrahydrocannabinol-9-carboxylic acid and its glucuronide in urine by capillary electrophoresis/mass spectrometry.  

PubMed

?(9) -Tetrahydrocannabinol is the primary psychoactive component in cannabis, one of the most commonly used illicit drugs in the world. This paper describes a simple and rapid method for direct analysis of major metabolites of ?(9) -tetrahydrocannabinol; 11-nor-?(9) -tetrahydrocannabinol-9-carboxylic acid and its glucuronide in urine by capillary electrophoresis/mass spectrometry. The only pretreatment needed for a urine sample was dilution with methanol containing an internal standard and centrifugation. Electrophoresis was carried out in an untreated fused-silica capillary (50 µm i.d. × 85 cm) filled with 40 m m ammonium formate (pH 6.4). An analysis could be completed within 10 min. For both compounds, the assay was linear over the range 0.1-10 µg/mL in urine with correlation coefficients (r(2) )?>0.99 and the limit of detection was 0.5 pg (10 nL injection). The detection yields and reproducibilities were determined at three different concentrations (0.1, 0.5 and 2 µg/mL in urine). The mean detection yields were 60-99%. The intra- and inter-day relative standard deviations of migration times were 0.063-0.19 and 0.18-0.36%, and those of peak areas were 4.2-18 and 5.9-25%, respectively. The proposed method successfully analyzed the urine samples of cannabis users. PMID:22419476

Iwamuro, Yoshiaki; Iio-Ishimaru, Reiko; Chinaka, Satoshi; Takayama, Nariaki; Hayakawa, Kazuichi

2012-11-01

410

Unimolecular dissociation of energy-selected ethyl formate ions  

NASA Astrophysics Data System (ADS)

The unimolecular dissociation of ethyl formate ions has been investigated using threshold photoelectron photoion coincidence mass spectrometry. The fragment ions appearing at low internal energies are C2H4CO+ and C2H4·+, whose appearance potentials are higher than the ionization energy of the ethyl formate molecule by 0.18 eV and 0.28 eV respectively. Observed decay rates for the formation of C2H4CO+ were found to be different to those of C2H4·+, although the direct fragmentation mechanism indicates that they should be identical. Furthermore, the rate constants predicted by RRKM/QET calculations are 104-105 times higher than the observed rate constants for both ions. The different decay rates probably result from different isomerization processes. One of the reaction channels is a stepwise McLafferty rearrangement involving a distonic intermediate, with charge retention on the olefin.

Zha, Qingmei; Nishimura, Toshihide; Meisels, G. G.

1992-10-01

411

[Influence of ethyl alcohol on diabetes pathogenesis type].  

PubMed

Relations between metabolism of carbohydrates and ethyl alcohol consumption became a subject of many research because they occur very frequently amongst alcoholics. One of the most often and dangerous effects of abusing ethanol is hypoglycemia. It is caused by hepatic gluconeogenesis disturbed by ethyl alcohol. Chronic result of abusing alcohol is chronic pancreas inflammation (PZT), what causes disorders of exo- and endocrine function of pancreas. Endocrine function is secretion of insulin and the glucagon what regulates metabolism of absorbed compounds. Failure of beta cells of Langerhans islets causes diabetes demanding insulin therapy. The ethanol can cause recurring diabetes resulting from damage of cells of Langerhans islets but can be also the risk factor of diabetes type 2. PMID:24779223

Zasimowicz, Elzbieta; Wolszczak, Blanka; Zasimowicz, Barbara

2014-03-01

412

Preparation of ethyl magnesium bromide for regiospecific analysis of triacylglycerols.  

PubMed

This paper presents a procedure for preparation of a Grignard reagent, ethyl magnesium bromide, used for partial deacylation of triacylglycerols (TAG) in their regiospecific analysis. Magnesium turnings were reacted with ethereal solution of bromoethane in a screw-capped test tube to synthesize 2 mL of 1 M ethyl magnesium bromide. Continuously stirred with a vortex mixer, the reaction smoot