Association of human liver bilirubin UDP-glucuronyltransferase activity with a polymorphism in the promoter region of the UGT1A1 gene

NARCIS (Netherlands)

Raijmakers, MTM; Jansen, PLM; Steegers, EAP; Peters, WHM

Background/Aims: Gilbert's syndrome is a benign form of a deficiency in bilirubin glucuronidation. It is associated with a homozygous polymorphism, A(TA)(7)TAA instead of A(TA)(6)TAA, in the TATA-box of the promoter region of the bilirubin UDP-glucuronyltransferase gene. In this study the

[Advances in research on regulatory effects of chemical ingredients of traditional Chinese medicine on UDP-glucuronosyltransferase 1A1 expression and activity].

Science.gov (United States)

Xin, Hong; Xu, Wei

2017-02-01

Uridine 5'-diphosphate-glucuronosyltransferase1A1(UGT1A1) is a major phase Ⅱ metabolism enzyme, responsible for glucuronidation and elimination of drugs and endogenous compounds, playing a vital role in sustaining endogenous metabolism balance. Therefore, changes in UGT1A1 expression/functional can not only cause adverse clinical drug/herbs-drug interactions, but also lead to metabolic disorder of endogenous substances, causing high blood bilirubin, bilirubin encephalopathy and liver injury, as well as other side effects. To date, many studies have found that a variety of clinical medicines and medicinal ingredients can regulate UGT1A1 activity. This article would summarize the advances in research on drug metabolism and toxicology in domestic and foreign literature, and investigate the regulatory effects of different types of traditional Chinese medicine(TCM) ingredients(such as flavonoids, coumarins, alkaloids) on UGT1A1 expression and activity, including inhibitory effect of TCM chemical ingredients on UGT1A1 and effect of TCM chemical ingredients on UGT1A1. It is hoped that this review could provide depth understanding and certain reference for the interaction between chemical ingredients of TCM and UGT1A1, which is of great significance to guide the rational clinical use in future. Copyright© by the Chinese Pharmaceutical Association.

The UDP glucuronosyltransferase gene superfamily: suggested nomenclature based on evolutionary divergence

NARCIS (Netherlands)

Burchell, B.; Nebert, D. W.; Nelson, D. R.; Bock, K. W.; Iyanagi, T.; Jansen, P. L.; Lancet, D.; Mulder, G. J.; Chowdhury, J. R.; Siest, G.

1991-01-01

A nomenclature system for the UDP glucuronosyltransferase superfamily is proposed, based on divergent evolution of the genes. A total of 26 distinct cDNAs in five mammalian species have been sequenced to date. Comparison of the deduced amino acid sequences leads to the definition of two families and

Structure–inhibition relationship of ginsenosides towards UDP-glucuronosyltransferases (UGTs)

International Nuclear Information System (INIS)

Fang, Zhong-Ze; Cao, Yun-Feng; Hu, Cui-Min; Hong, Mo; Sun, Xiao-Yu; Ge, Guang-Bo; Liu, Yong; Zhang, Yan-Yan; Yang, Ling; Sun, Hong-Zhi

2013-01-01

The wide utilization of ginseng provides the high risk of herb–drug interaction (HDI) with many clinical drugs. The inhibition of ginsenosides towards drug-metabolizing enzymes (DMEs) has been regarded as an important reason for herb–drug interaction (HDI). Compared with the deep studies on the ginsenosides' inhibition towards cytochrome P450 (CYP), the inhibition of ginsenosides towards the important phase II enzymes UDP-glucuronosyltransferases (UGTs) remains to be unclear. The present study aims to evaluate the inhibition behavior of ginsenosides towards important UGT isoforms located in the liver and intestine using in vitro methods. The recombinant UGT isoform-catalyzed 4-methylumbelliferone (4-MU) glucuronidation reaction was employed as in vitro probe reaction. The results showed that structure-dependent inhibition existed for the inhibition of ginsenosides towards UGT isoforms. To clarify the possibility of in vivo herb–drug interaction induced by this kind of inhibition, the ginsenoside Rg 3 was selected as an example, and the inhibition kinetic type and parameters (K i ) were determined. Rg 3 competitively inhibited UGT1A7, 2B7 and 2B15-catalyzed 4-MU glucuronidation reaction, and exerted noncompetitive inhibition towards UGT1A8-catalyzed 4-MU glucuronidation. The inhibition parameters (K i values) were calculated to be 22.6, 7.9, 1.9, and 2.0 μM for UGT1A7, 1A8, 2B7 and 2B15. Using human maximum plasma concentration of Rg 3 (400 ng/ml (0.5 μM)) after intramuscular injection of 60 mg Rg 3 , the area under the plasma concentration-time curve (AUC) was extrapolated to increase by 2.2%, 6.3%, 26.3%, and 25% for the co-administered drugs completely undergoing the metabolism catalyzed by UGT1A7, 1A8, 2B7 and 2B15, respectively. All these results indicated that the ginsenosides' inhibition towards UGT isoforms might be an important reason for ginseng–drug interaction. - Highlights: ► Structure-dependent inhibition of ginsenoside towards UDP-glucuronosyltransferases

Structure–inhibition relationship of ginsenosides towards UDP-glucuronosyltransferases (UGTs)

Energy Technology Data Exchange (ETDEWEB)

Fang, Zhong-Ze [The First Affiliated Hospital of Liaoning Medical University, Jinzhou 121001 (China); Joint Center for Translational Medicine, Dalian Institute of Chemical Physics Chinese Academy of Sciences and The first Affiliated Hospital of Liaoning Medical University, No.457, Zhongshan Road, Dalian 116023 (China); Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892 (United States); Cao, Yun-Feng [Key Laboratory of Contraceptives and Devices Research(NPFPC),Shanghai Engineer and Technology Research Center of Reproductive Health Drug and Devices, Shanghai Institute of Planned Parenthood Research, Shanghai 200032 (China); Joint Center for Translational Medicine, Dalian Institute of Chemical Physics Chinese Academy of Sciences and The first Affiliated Hospital of Liaoning Medical University, No.457, Zhongshan Road, Dalian 116023 (China); Hu, Cui-Min [Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892 (United States); Hong, Mo; Sun, Xiao-Yu [Joint Center for Translational Medicine, Dalian Institute of Chemical Physics Chinese Academy of Sciences and The first Affiliated Hospital of Liaoning Medical University, No.457, Zhongshan Road, Dalian 116023 (China); Ge, Guang-Bo; Liu, Yong; Zhang, Yan-Yan; Yang, Ling [Laboratory of Pharmaceutical Resource Discovery, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023 Dalian (China); Sun, Hong-Zhi, E-mail: zzfang228@gmail.com [The First Affiliated Hospital of Liaoning Medical University, Jinzhou 121001 (China)

2013-03-01

The wide utilization of ginseng provides the high risk of herb–drug interaction (HDI) with many clinical drugs. The inhibition of ginsenosides towards drug-metabolizing enzymes (DMEs) has been regarded as an important reason for herb–drug interaction (HDI). Compared with the deep studies on the ginsenosides' inhibition towards cytochrome P450 (CYP), the inhibition of ginsenosides towards the important phase II enzymes UDP-glucuronosyltransferases (UGTs) remains to be unclear. The present study aims to evaluate the inhibition behavior of ginsenosides towards important UGT isoforms located in the liver and intestine using in vitro methods. The recombinant UGT isoform-catalyzed 4-methylumbelliferone (4-MU) glucuronidation reaction was employed as in vitro probe reaction. The results showed that structure-dependent inhibition existed for the inhibition of ginsenosides towards UGT isoforms. To clarify the possibility of in vivo herb–drug interaction induced by this kind of inhibition, the ginsenoside Rg{sub 3} was selected as an example, and the inhibition kinetic type and parameters (K{sub i}) were determined. Rg{sub 3} competitively inhibited UGT1A7, 2B7 and 2B15-catalyzed 4-MU glucuronidation reaction, and exerted noncompetitive inhibition towards UGT1A8-catalyzed 4-MU glucuronidation. The inhibition parameters (K{sub i} values) were calculated to be 22.6, 7.9, 1.9, and 2.0 μM for UGT1A7, 1A8, 2B7 and 2B15. Using human maximum plasma concentration of Rg{sub 3} (400 ng/ml (0.5 μM)) after intramuscular injection of 60 mg Rg{sub 3}, the area under the plasma concentration-time curve (AUC) was extrapolated to increase by 2.2%, 6.3%, 26.3%, and 25% for the co-administered drugs completely undergoing the metabolism catalyzed by UGT1A7, 1A8, 2B7 and 2B15, respectively. All these results indicated that the ginsenosides' inhibition towards UGT isoforms might be an important reason for ginseng–drug interaction. - Highlights: ► Structure

Inhibitory Effects of Commonly Used Herbal Extracts on UDP-Glucuronosyltransferase 1A4, 1A6, and 1A9 Enzyme Activities

Science.gov (United States)

Mohamed, Mohamed-Eslam F.

2011-01-01

The aim of this study was to investigate the effect of commonly used botanicals on UDP-glucuronosyltransferase (UGT) 1A4, UGT1A6, and UGT1A9 activities in human liver microsomes. The extracts screened were black cohosh, cranberry, echinacea, garlic, ginkgo, ginseng, milk thistle, saw palmetto, and valerian in addition to the green tea catechin epigallocatechin gallate (EGCG). Formation of trifluoperazine glucuronide, serotonin glucuronide, and mycophenolic acid phenolic glucuronide was used as an index reaction for UGT1A4, UGT1A6, and UGT1A9 activities, respectively, in human liver microsomes. Inhibition potency was expressed as the concentration of the inhibitor at 50% activity (IC50) and the volume in which the dose could be diluted to generate an IC50-equivalent concentration [volume/dose index (VDI)]. Potential inhibitors were EGCG for UGT1A4, milk thistle for both UGT1A6 and UGT1A9, saw palmetto for UGT1A6, and cranberry for UGT1A9. EGCG inhibited UGT1A4 with an IC50 value of (mean ± S.E.) 33.8 ± 3.1 μg/ml. Milk thistle inhibited both UGT1A6 and UGT1A9 with IC50 values of 59.5 ± 3.6 and 33.6 ± 3.1 μg/ml, respectively. Saw palmetto and cranberry weakly inhibited UGT1A6 and UGT1A9, respectively, with IC50 values >100 μg/ml. For each inhibition, VDI was calculated to determine the potential of achieving IC50-equivalent concentrations in vivo. VDI values for inhibitors indicate a potential for inhibition of first-pass glucuronidation of UGT1A4, UGT1A6, and UGT1A9 substrates. These results highlight the possibility of herb-drug interactions through modulation of UGT enzyme activities. Further clinical studies are warranted to investigate the in vivo extent of the observed interactions. PMID:21632963

Genetic variability of aryl hydrocarbon receptor (AhR)-mediated regulation of the human UDP glucuronosyltransferase (UGT) 1A4 gene

Energy Technology Data Exchange (ETDEWEB)

Erichsen, Thomas J; Ehmer, Ursula; Kalthoff, Sandra; Lankisch, Tim O; Mueller, Tordis M [Department of Gastroenterology, Hepatology and Endocrinology, Hannover, Medical School, Hannover (Germany); Munzel, Peter A [Department of Toxicology, Institute of Pharmacology and Toxicology, University of Tubingen, Tubingen (Germany); Manns, Michael P [Department of Gastroenterology, Hepatology and Endocrinology, Hannover, Medical School, Hannover (Germany); Strassburg, Christian P. [Department of Gastroenterology, Hepatology and Endocrinology, Hannover, Medical School, Hannover (Germany)], E-mail: strassburg.christian@mh-hannover.de

2008-07-15

UDP glucuronosyltransferases (UGTs) play an important role for drug detoxification and toxicity. UGT function is genetically modulated by single nucleotide polymorphisms (SNPs) which lead to the expression of functionally altered protein, or altered expression levels. UGT1A4 activity includes anticonvulsants, antidepressants and environmental mutagens. In this study the induction of the human UGT1A4 gene and a potential influence of genetic variation in its promoter region were analyzed. SNPs at bp - 219 and - 163 occurred in 9% among 109 blood donors reducing UGT1A4 transcription by 40%. UGT1A4 transcription was dioxin inducible. Reporter gene experiments identified 2 xenobiotic response elements (XRE), which were functionally confirmed by mutagenesis analyses, and binding was demonstrated by electromobility shift assays. Constitutive human UGT1A4 gene expression and induction was aryl hydrocarbon receptor (AhR)-dependent, and reduced in the presence of SNPs at bp - 219 and - 163. AhR-mediated regulation of the human UGT1A4 gene by two XRE and a modulation by naturally occurring genetic variability by SNPs is demonstrated, which indicates gene-environment interaction with potential relevance for drug metabolism.

Genetic variability of aryl hydrocarbon receptor (AhR)-mediated regulation of the human UDP glucuronosyltransferase (UGT) 1A4 gene

International Nuclear Information System (INIS)

Erichsen, Thomas J.; Ehmer, Ursula; Kalthoff, Sandra; Lankisch, Tim O.; Mueller, Tordis M.; Munzel, Peter A.; Manns, Michael P.; Strassburg, Christian P.

2008-01-01

UDP glucuronosyltransferases (UGTs) play an important role for drug detoxification and toxicity. UGT function is genetically modulated by single nucleotide polymorphisms (SNPs) which lead to the expression of functionally altered protein, or altered expression levels. UGT1A4 activity includes anticonvulsants, antidepressants and environmental mutagens. In this study the induction of the human UGT1A4 gene and a potential influence of genetic variation in its promoter region were analyzed. SNPs at bp - 219 and - 163 occurred in 9% among 109 blood donors reducing UGT1A4 transcription by 40%. UGT1A4 transcription was dioxin inducible. Reporter gene experiments identified 2 xenobiotic response elements (XRE), which were functionally confirmed by mutagenesis analyses, and binding was demonstrated by electromobility shift assays. Constitutive human UGT1A4 gene expression and induction was aryl hydrocarbon receptor (AhR)-dependent, and reduced in the presence of SNPs at bp - 219 and - 163. AhR-mediated regulation of the human UGT1A4 gene by two XRE and a modulation by naturally occurring genetic variability by SNPs is demonstrated, which indicates gene-environment interaction with potential relevance for drug metabolism

PPARα: A Master Regulator of Bilirubin Homeostasis

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Cyril Bigo

2014-01-01

Full Text Available Hypolipidemic fibrates activate the peroxisome proliferator-activated receptor (PPAR α to modulate lipid oxidation and metabolism. The present study aimed at evaluating how 3 PPARα agonists, namely, fenofibrate, gemfibrozil, and Wy14,643, affect bilirubin synthesis and metabolism. Human umbilical vein epithelial cells (HUVEC and coronary artery smooth muscle cells (CASMC were cultured in the absence or presence of the 3 activators, and mRNA, protein, and/or activity levels of the bilirubin synthesizing heme oxygenase- (HO- 1 and biliverdin reductase (BVR enzymes were determined. Human hepatocytes (HH and HepG2 cells sustained similar treatments, except that the expression of the bilirubin conjugating UDP-glucuronosyltransferase (UGT 1A1 enzyme and multidrug resistance-associated protein (MRP 2 transporter was analyzed. In HUVECs, gemfibrozil, fenofibrate, and Wy14,643 upregulated HO-1 mRNA expression without affecting BVR. Wy14,643 and fenofibrate also caused HO-1 protein accumulation, while gemfibrozil and fenofibrate favored the secretion of bilirubin in cell media. Similar positive regulations were also observed with the 3 PPARα ligands in CASMCs where HO-1 mRNA and protein levels were increased. In HH and HepG2 cells, both UGT1A1 and MRP2 transcripts were also accumulating. These observations indicate that PPARα ligands activate bilirubin synthesis in vascular cells and metabolism in liver cells. The clinical implications of these regulatory events are discussed.

Enantioselective inhibition of carprofen towards UDP-glucuronosyltransferase (UGT) 2B7.

Science.gov (United States)

Fang, Zhong-Ze; Wang, Haina; Cao, Yun-Feng; Sun, Dong-Xue; Wang, Li-Xuan; Hong, Mo; Huang, Ting; Chen, Jian-Xing; Zeng, Jia

2015-03-01

UDP-glucuronosyltransferases (UGTs)-catalyzed glucuronidation conjugation reaction plays an important role in the elimination of many important clinical drugs and endogenous substances. The present study aims to investigate the enantioselective inhibition of carprofen towards UGT isoforms. In vitro a recombinant UGT isoforms-catalyzed 4-methylumbelliferone (4-MU) glucuronidation incubation mixture was used to screen the inhibition potential of (R)-carprofen and (S)-carprofen towards multiple UGT isoforms. The results showed that (S)-carprofen exhibited stronger inhibition potential than (R)-carprofen towards UGT2B7. However, no significant difference was observed for the inhibition of (R)-carprofen and (S)-carprofen towards other UGT isoforms. Furthermore, the inhibition kinetic behavior was compared for the inhibition of (S)-carprofen and (R)-carprofen towards UGT2B7. A Lineweaver-Burk plot showed that both (S)-carprofen and (R)-carprofen exhibited competitive inhibition towards UGT2B7-catalyzed 4-MU glucuronidation. The inhibition kinetic parameter (Ki ) was calculated to be 7.0 μM and 31.1 μM for (S)-carprofen and (R)-carprofen, respectively. Based on the standard for drug-drug interaction, the threshold for (S)-carprofen and (R)-carprofen to induce a drug-drug interaction is 0.7 μM and 3.1 μM, respectively. In conclusion, enantioselective inhibition of carprofen towards UDP-glucuronosyltransferase (UGT) 2B7 was demonstrated in the present study. Using the in vitro inhibition kinetic parameter, the concentration threshold of (S)-carprofen and (R)-carprofen to possibly induce the drug-drug interaction was obtained. Therefore, clinical monitoring of the plasma concentration of (S)-carprofen is more important than (R)-carprofen to avoid a possible drug-drug interaction between carprofen and the drugs mainly undergoing UGT2B7-catalyzed metabolism. © 2014 Wiley Periodicals, Inc.

Deficient UDP-glucuronosyltransferase detoxification enzyme activity in the small intestinal mucosa of patients with coeliac disease.

NARCIS (Netherlands)

Goerres, M.S.; Roelofs, H.M.J.; Jansen, J.B.M.J.; Peters, W.H.M.

2006-01-01

BACKGROUND: Small intestinal malignancies in humans are rare; however, patients with coeliac disease have a relatively high risk for such tumours. Intestinal UDP-glucuronosyltransferases are phase II drug metabolism enzymes also involved in the detoxification of ingested toxins and carcinogens. As

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

Science.gov (United States)

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

2013-09-01

Vanillin is a food flavoring agent widely utilized in foods, beverages, drugs, and perfumes and has been demonstrated to exhibit multiple pharmacological activities. Given the importance of glucuronidation in the metabolism of vanillin, the UDP-glucuronosyltransferase conjugation pathway of vanillin was investigated in this study. Vanillin glucuronide was identified by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and a hydrolysis reaction catalyzed by β-glucuronidase. The kinetic study showed that vanillin glucuronidation by HLMs and HIMs followed Michaelis-Menten kinetics and the kinetic parameters were as follows: 134.9 ± 13.5 μM and 81.3 ± 11.3 μM for K(m) of HLMs and HIMs, 63.8 ± 2.0 nmol/min/mg pro and 13.4 ±2.0 nmol/min/mg pro for Vmax of HLMs and HIMs. All UDP-glucuronosyltransferase (UGT) isoforms except UGT1A4, 1A9, and 2B7 showed the capability to glucuronidate vanillin, and UGT1A6 exerted the higher V(max)/K(m) values than other UGT isoforms for the glucuronidation of vanillin when assuming expression of isoforms is similar in recombinant UGTs. Kinetic analysis using liver microsomes from six studied speices indicated that vanillin had highest affinity for the monkey liver microsomes enzyme (K(m)  = 25.6 ± 3.2 μM) and the lowest affinity for the mice liver microsomes enzyme (K(m)  = 149.1 ± 18.4 μM), and intrinsic clearance was in the following order: monkey > dog > minipig > mice > rat ~ human. These data collectively provided important information for understanding glucuronidation of vanillin. Copyright © 2012 John Wiley & Sons, Ltd.

Chirality Influence of Zaltoprofen Towards UDP-Glucuronosyltransferases (UGTs) Inhibition Potential.

Science.gov (United States)

Jia, Lin; Hu, Cuimin; Wang, Haina; Liu, Yongzhe; Liu, Xin; Zhang, Yan-Yan; Li, Wei; Wang, Li-Xuan; Cao, Yun-Feng; Fang, Zhong-Ze

2015-06-01

Zaltoprofen (ZLT) is a nonsteroidal antiinflammation drug, and has been clinically employed to treat rheumatoid arthritis, osteoarthritis, and other chronic inflammatory pain conditions. The present study aims to investigate the chirality influence of zaltoprofen towards the inhibition potential towards UDP-glucuronosyltransferases (UGTs) isoforms. In vitro a recombinant UGT isoforms-catalyzed 4-methylumbelliferone (4-MU) glucuronidation incubation system was employed to investigate the inhibition of (R)-zaltoprofen and (S)-zaltoprofen towards UGT isoforms. The inhibition difference capability was observed for the inhibition of (R)-zaltoprofen and (S)-zaltoprofen towards UGT1A8 and UGT2B7, but not for other tested UGT isoforms. (R)-zaltoprofen exhibited noncompetitive inhibition towards UGT1A8 and competitive inhibition towards UGT2B7. The inhibition kinetic parameters were calculated to be 35.3 μM and 19.2 μM for UGT1A8 and UGT2B7. (R)-zaltoprofen and (S)-zaltoprofen exhibited a different inhibition type towards UGT1A7. Based on the reported maximum plasma concentration of (R)-zaltoprofen in vivo, a high drug-drug interaction between (R)-zaltoprofen and the drugs mainly undergoing UGT1A7, UGT1A8, and UGT2B7-catalyzed glucuronidation was indicated. © 2015 Wiley Periodicals, Inc.

Constitutive androstane receptor activation promotes bilirubin clearance in a murine model of alcoholic liver disease.

Science.gov (United States)

Wang, Xiuyan; Zheng, Liyu; Wu, Jinming; Tang, Binbin; Zhang, Mengqin; Zhu, Debin; Lin, Xianfan

2017-06-01

Increased plasma levels of bilirubin have been reported in rat models and patients with alcoholic liver disease (ALD). The constitutive androstane receptor (CAR) is a known xenobiotic receptor, which induces the detoxification and transport of bilirubin. In the present study, the bilirubin transport regulatory mechanisms, and the role of CAR activation in hepatic and extrahepatic bilirubin clearance were investigated in a murine model of ALD. The mice were fed a Lieber-DeCarli ethanol diet or an isocaloric control diet for 4 weeks, followed by the administration of CAR agonists, 1,4-bis-[2‑(3,5-dichlorpyridyloxy)]benzene (TCPOBOP) and phenobarbital (PB), and their vehicles to examine the effect of the pharmacological activation of CAR on serum levels of bilirubin and on the bilirubin clearance pathway in ALD by serological survey, western blotting and reverse transcription‑quantitative polymerase chain reaction. The results showed that chronic ethanol ingestion impaired the nuclear translocation of CAR, which was accompanied by elevated serum levels of bilirubin, suppression of the expression of hepatic and renal organic anion transporting polypeptide (OATP) 1A1 and hepatic multidrug resistance‑associated protein 2 (MRP2), and induction of the expression of UDP-glucuronosyltransferase (UGT) 1A1. The activation of CAR by TCPOBOP and PB resulted in downregulation of the serum levels of bilirubin followed by selective upregulation of the expression levels of OATP1A1, OATP1A4, UGT1A1 and MRP2 in ALD. These results revealed the bilirubin transport regulatory mechanisms and highlighted the importance of CAR in modulating the bilirubin clearance pathway in the ALD mouse model.

Bilirubin as a potential causal factor in type 2 diabetes risk: a Mendelian randomization study

Science.gov (United States)

Abbasi, Ali; Deetman, Petronella E.; Corpeleijn, Eva; Gansevoort, Ron T.; Gans, Rijk O.B.; Hillege, Hans L.; van der Harst, Pim; Stolk, Ronald P.; Navis, Gerjan; Alizadeh, Behrooz Z.; Bakker, Stephan J.L.

2014-01-01

Circulating bilirubin, a natural antioxidant, is associated with decreased risk of type 2 diabetes (T2D), but the nature of the relationship remains unknown. We performed Mendelian randomization in a prospective cohort of 3,381 participants free of diabetes at baseline (aged 28-75 years; women, 52.6%). We used rs6742078 located in UDP-glucuronosyltransferase (UGT1A1) locus as instrumental variable (IV) to study a potential causal effect of serum total bilirubin on T2D risk. T2D developed in a total of 210 (6.2%) participants during a median follow-up of 7.8 years. In adjusted analyses, rs6742078, which explained 19.5% of bilirubin variation, was strongly associated with total bilirubin (a 0.68-SD increase in bilirubin levels per T allele; Pbilirubin levels, we observed a 25% (OR 0.75 [95%CI, 0.62-0.92]; P=0.004) lower risk of T2D. In Mendelian randomization analysis, the causal risk reduction for T2D was estimated to be 42% (causal ORIVestimation per 1-SD increase in log-transformed bilirubin 0.58 [95%CI, 0.39-0.84]; P=0.005), which was comparable to the observational estimate (Durbin-Wu-Hausman chi-square test Pfor difference =0.19). These novel results provide evidence that elevated bilirubin is causally associated with risk of T2D and support its role as a protective determinant. PMID:25368098

Cooperation of NAD(P)H:quinone oxidoreductase 1 and UDP-glucuronosyltransferases reduces menadione cytotoxicity in HEK293 cells.

Science.gov (United States)

Nishiyama, Takahito; Izawa, Tadashi; Usami, Mami; Ohnuma, Tomokazu; Ogura, Kenichiro; Hiratsuka, Akira

2010-04-09

Previous studies have shown that NAD(P)H:quinone oxidoreductase 1 (NQO1) plays an important role in the detoxification of menadione (2-methyl-1,4-naphthoquinone, also known as vitamin K3). However, menadiol (2-methyl-1,4-naphthalenediol) formed from menadione by NQO1-mediated reduction continues to be an unstable substance, which undergoes the reformation of menadione with concomitant formation of reactive oxygen species (ROS). Hence, we focused on the roles of phase II enzymes, with particular attention to UDP-glucuronosyltransferases (UGTs), in the detoxification process of menadione. In this study, we established an HEK293 cell line stably expressing NQO1 (HEK293/NQO1) and HEK293/NQO1 cell lines with doxycycline (DOX)-regulated expression of UGT1A6 (HEK293/NQO1/UGT1A6) and UGT1A10 (HEK293/NQO1/UGT1A10), and evaluated the role of NQO1 and UGTs against menadione-induced cytotoxicity. Our results differed from those of previous studies. HEK293/NQO1 was the most sensitive cell line to menadione cytotoxicity among cell lines established in this study. These phenomena were also observed in HEK293/NQO1/UGT1A6 and HEK293/NQO1/UGT1A10 cells in which the expression of UGT was suppressed by DOX treatment. On the contrary, HEK293/NQO1/UGT1A6 and HEK293/NQO1/UGT1A10 cells without DOX treatment were resistant to menadione-induced cytotoxicity. These results demonstrated that NQO1 is not a detoxification enzyme for menadione and that UGT-mediated glucuronidation of menadiol is the most important detoxification process. Copyright 2009 Elsevier Inc. All rights reserved.

The Inhibition of the Components from Shengmai Injection towards UDP-Glucuronosyltransferase

Directory of Open Access Journals (Sweden)

Li-Peng Jiang

2014-01-01

Full Text Available The mechanism of shengmai injection- (SMI- related drug-drug interaction remains unclear. Evaluation of the inhibition potential of SMI’s ingredients towards UDP-glucuronosyltransferases (UGTs activity will provide a new insight to understand SMI-related drug-drug interaction. In vitro incubation system to model UGT reaction was used. Recombinant UGT isoforms-catalyzed 4-methylumbelliferone (4-MU glucuronidation and UGT1A4-catalyzed trifluoperazine (TFP glucuronidation reactions were employed to phenotype the inhibition profile of maidong’s components towards the activity of UGT isoforms. Different inhibition potential of maidong’s components towards various UGT isoforms was observed. Based on the inhibition kinetic investigation results, ophiopogonin D (OD noncompetitively inhibited UGT1A6 and competitively inhibited UGT1A8, ophiopogonin D′ (OD′ noncompetitively inhibited UGT1A6 and UGT1A10, and ruscorectal (RU exhibited competitive inhibition towards UGT1A4. The inhibition kinetic parameters were calculated to be 20.6, 40.1, 5.3, 9.0, and 0.02 μM, respectively. In combination with our previous results obtained for the inhibition of UGT isoforms by ginsenosides and wuweizi components, the important SMI ingredients exhibiting strong inhibition towards UGT isoforms were highlighted. All the results obtained in the present study provide a new insight to understand SMI-related drug-drug interaction.

Regulation of UDP glucuronosyltransferases in the gastrointestinal tract

International Nuclear Information System (INIS)

Gregory, Philip A.; Lewinsky, Rikke H.; Gardner-Stephen, Dione A.; Mackenzie, Peter I.

2004-01-01

The UDP glucuronosyltransferases (UGT) of the gastrointestinal (GI) tract have a crucial role in protection against the toxic effects of lipophilic chemicals in the environment. UGTs such as UGT1A7, UGT1A8, and UGT1A10 are exclusively expressed in gastrointestinal tissues, each with a unique tissue distribution pattern that is subject to interindividual variation. The factors regulating this tissue-specific expression and that contribute to variability are beginning to be elucidated. Studies on the UGT1A7, 1A8, 1A9, and 1A10 gene promoters in Caco-2 cells, an in vitro model of enterocytes of the gastrointestinal tract, have identified the caudal homeodomain transcription factor, Cdx2, as an important regulator of the UGT1A8 and 1A10 gene proximal promoters. This transcription factor is found exclusively in the small intestine and colon: it is absent in the gastric epithelium and the esophagus. Cdx2 regulates the UGT1A8 and 1A10 promoters in cooperation with hepatocyte nuclear factor 1α (HNF1α). It is noteworthy that UGT1A7 is not expressed in gastrointestinal tissue distal to the gastric mucosa and does not contain a Cdx2 binding site in its proximal promoter. Transcription factors, including Sp1, which differentially bind to the initiator regions of the UGT1A8, 1A9, and 1A10 promoters, also contribute to the differences in expression of these UGTs in Caco-2 cells. The identification of important regulatory regions of UGT genes expressed in the gastrointestinal tract, and the transcription factors that bind to these regions, will aid in the elucidation of factors that contribute to interindividual differences in gastrointestinal UGT expression. In turn, this will lead to further understanding of interindividual variation in the capacity of the GI tract to metabolize lipophilic chemicals and to act as a barrier to dietary toxins and orally administered drugs

UDP glucuronosyltransferase (UGT) 1A6 pharmacogenetics: I. Identification of polymorphisms in the 5'-regulatory and exon 1 regions, and association with human liver UGT1A6 gene expression and glucuronidation.

Science.gov (United States)

Krishnaswamy, Soundararajan; Hao, Qin; Al-Rohaimi, Abdul; Hesse, Leah M; von Moltke, Lisa L; Greenblatt, David J; Court, Michael H

2005-06-01

UDP glucuronosyltransferase (UGT) 1A6 is a major isoform in human liver that glucuronidates numerous drugs, toxins, and endogenous substrates with high interindividual variability. The molecular basis for this variability remains unknown, although it likely involves genetic and environmental factors. Phenotype-genotype studies were conducted using a well characterized human liver bank (n = 54) and serotonin glucuronidation as a UGT1A6-specific phenotype marker. A positive moderate-to-heavy alcohol use history (>14 drinks per week) was the only demographic factor examined that correlated with phenotype and was associated with 2-fold higher serotonin glucuronidation (p g, -1310del5, and -652g-->a). Initial univariate analyses did not identify any significant phenotype-genotype associations. However, in livers without substantial alcohol exposure, 50% lower UGT1A6 mRNA levels (p = 0.026) were found in carriers of the linked S7A-enhancer polymorphisms compared with noncarriers but without significant effect on UGT1A6 protein content or glucuronidation activities. Three major haplotypes, including (*)1A (reference), (*)1B (-1535g-->a and -427g-->c), and (*)2 (-1710c-->g, -1310del5, -652g-->a, S7A, T181A, and R184S), were identified, accounting for 90% of alleles. No association of haplotype with any of the phenotype measures could be discerned. In conclusion, although the identified UGT1A6 polymorphisms did not explain the observed glucuronidation variability, there does seem to be a significant role for environmental factors associated with alcohol consumption.

High Expression of UGT1A1/1A6 in Monkey Small Intestine: Comparison of Protein Expression Levels of Cytochromes P450, UDP-Glucuronosyltransferases, and Transporters in Small Intestine of Cynomolgus Monkey and Human.

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Akazawa, Takanori; Uchida, Yasuo; Miyauchi, Eisuke; Tachikawa, Masanori; Ohtsuki, Sumio; Terasaki, Tetsuya

2018-01-02

Cynomolgus monkeys have been widely used for the prediction of drug absorption in humans. The purpose of this study was to clarify the regional protein expression levels of cytochromes P450 (CYPs), UDP-glucuronosyltransferases (UGTs), and transporters in small intestine of cynomolgus monkey using liquid chromatography-tandem mass spectrometry, and to compare them with the corresponding levels in human. UGT1A1 in jejunum and ileum were >4.57- and >3.11-fold and UGT1A6 in jejunum and ileum were >16.1- and >8.57-fold, respectively, more highly expressed in monkey than in human. Also, jejunal expression of monkey CYP3A8 (homologue of human CYP3A4) was >3.34-fold higher than that of human CYP3A4. Among apical drug efflux transporters, BCRP showed the most abundant expression in monkey and human, and the expression levels of BCRP in monkey and human were >1.74- and >1.25-fold greater than those of P-gp and >2.76- and >4.50-fold greater than those of MRP2, respectively. These findings should be helpful to understand species differences of the functions of CYPs, UGTs, and transporters between monkey and human. The UGT1A1/1A6 data would be especially important because it is difficult to identify isoforms responsible for species differences of intestinal glucuronidation by means of functional studies due to overlapping substrate specificity.

Albumin stimulates the activity of the human UDP-glucuronosyltransferases 1A7, 1A8, 1A10, 2A1 and 2B15, but the effects are enzyme and substrate dependent.

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Manevski, Nenad; Troberg, Johanna; Svaluto-Moreolo, Paolo; Dziedzic, Klaudyna; Yli-Kauhaluoma, Jari; Finel, Moshe

2013-01-01

Human UDP-glucuronosyltransferases (UGTs) are important enzymes in metabolic elimination of endo- and xenobiotics. It was recently shown that addition of fatty acid free bovine serum albumin (BSA) significantly enhances in vitro activities of UGTs, a limiting factor in in vitro-in vivo extrapolation. Nevertheless, since only few human UGT enzymes were tested for this phenomenon, we have now performed detailed enzyme kinetic analysis on the BSA effects in six previously untested UGTs, using 2-4 suitable substrates for each enzyme. We also examined some of the previously tested UGTs, but using additional substrates and a lower BSA concentration, only 0.1%. The latter concentration allows the use of important but more lipophilic substrates, such as estradiol and 17-epiestradiol. In five newly tested UGTs, 1A7, 1A8, 1A10, 2A1, and 2B15, the addition of BSA enhanced, to a different degree, the in vitro activity by either decreasing reaction's K(m), increasing its V(max), or both. In contrast, the activities of UGT2B17, another previously untested enzyme, were almost unaffected. The results of the assays with the previously tested UGTs, 1A1, 1A6, 2B4, and 2B7, were similar to the published BSA only as far as the BSA effects on the reactions' K(m) are concerned. In the cases of V(max) values, however, our results differ significantly from the previously published ones, at least with some of the substrates. Hence, the magnitude of the BSA effects appears to be substrate dependent, especially with respect to V(max) increases. Additionally, the BSA effects may be UGT subfamily dependent since K(m) decreases were observed in members of subfamilies 1A, 2A and 2B, whereas large V(max) increases were only found in several UGT1A members. The results shed new light on the complexity of the BSA effects on the activity and enzyme kinetics of the human UGTs.

Albumin stimulates the activity of the human UDP-glucuronosyltransferases 1A7, 1A8, 1A10, 2A1 and 2B15, but the effects are enzyme and substrate dependent.

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Nenad Manevski

Full Text Available Human UDP-glucuronosyltransferases (UGTs are important enzymes in metabolic elimination of endo- and xenobiotics. It was recently shown that addition of fatty acid free bovine serum albumin (BSA significantly enhances in vitro activities of UGTs, a limiting factor in in vitro-in vivo extrapolation. Nevertheless, since only few human UGT enzymes were tested for this phenomenon, we have now performed detailed enzyme kinetic analysis on the BSA effects in six previously untested UGTs, using 2-4 suitable substrates for each enzyme. We also examined some of the previously tested UGTs, but using additional substrates and a lower BSA concentration, only 0.1%. The latter concentration allows the use of important but more lipophilic substrates, such as estradiol and 17-epiestradiol. In five newly tested UGTs, 1A7, 1A8, 1A10, 2A1, and 2B15, the addition of BSA enhanced, to a different degree, the in vitro activity by either decreasing reaction's K(m, increasing its V(max, or both. In contrast, the activities of UGT2B17, another previously untested enzyme, were almost unaffected. The results of the assays with the previously tested UGTs, 1A1, 1A6, 2B4, and 2B7, were similar to the published BSA only as far as the BSA effects on the reactions' K(m are concerned. In the cases of V(max values, however, our results differ significantly from the previously published ones, at least with some of the substrates. Hence, the magnitude of the BSA effects appears to be substrate dependent, especially with respect to V(max increases. Additionally, the BSA effects may be UGT subfamily dependent since K(m decreases were observed in members of subfamilies 1A, 2A and 2B, whereas large V(max increases were only found in several UGT1A members. The results shed new light on the complexity of the BSA effects on the activity and enzyme kinetics of the human UGTs.

Comparison of the inhibitory effects of tolcapone and entacapone against human UDP-glucuronosyltransferases

Energy Technology Data Exchange (ETDEWEB)

Lv, Xia [Laboratory of Pharmaceutical Resource Discovery, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); State Key Laboratory of Organ Failure Research, Guangdong Provincial Institute of Nephrology, Southern Medical University, Guangzhou 510515 (China); Wang, Xin-Xin [RSKT Biopharma Inc., Dalian 116023 (China); Hou, Jie [Dalian Medical University, Dalian 116044 (China); Fang, Zhong-Ze [RSKT Biopharma Inc., Dalian 116023 (China); Wu, Jing-Jing [Laboratory of Pharmaceutical Resource Discovery, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); State Key Laboratory of Organ Failure Research, Guangdong Provincial Institute of Nephrology, Southern Medical University, Guangzhou 510515 (China); Cao, Yun-Feng [RSKT Biopharma Inc., Dalian 116023 (China); Liu, Shu-Wen [State Key Laboratory of Organ Failure Research, Guangdong Provincial Institute of Nephrology, Southern Medical University, Guangzhou 510515 (China); Ge, Guang-Bo, E-mail: geguangbo@dicp.ac.cn [Laboratory of Pharmaceutical Resource Discovery, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); State Key Laboratory of Organ Failure Research, Guangdong Provincial Institute of Nephrology, Southern Medical University, Guangzhou 510515 (China); Yang, Ling, E-mail: ylingdicp@gmail.com [Laboratory of Pharmaceutical Resource Discovery, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Jiangxi University of Traditional Chinese Medicine, Nanchang 330006 (China)

2016-06-15

Tolcapone and entacapone are two potent catechol-O-methyltransferase (COMT) inhibitors with a similar skeleton and displaying similar pharmacological activities. However, entacapone is a very safe drug used widely in the treatment of Parkinson's disease, while tolcapone is only in limited use for Parkinson's patients and needs careful monitoring of hepatic functions due to hepatotoxicity. This study aims to investigate and compare the inhibitory effects of entacapone and tolcapone on human UDP-glucosyltransferases (UGTs), as well as to evaluate the potential risks from the view of drug-drug interactions (DDI). The results demonstrated that both tolcapone and entacapone exhibited inhibitory effects on UGT1A1, UGT1A7, UGT1A9 and UGT1A10. In contrast to entacapone, tolcapone exhibited more potent inhibitory effects on UGT1A1, UGT1A7, and UGT1A10, while their inhibitory potentials against UGT1A9 were comparable. It is noteworthy that the inhibition constants (K{sub i}) of tolcapone and entacapone against bilirubin-O-glucuronidation in human liver microsomes (HLM) are determined as 0.68 μM and 30.82 μM, respectively, which means that the inhibition potency of tolcapone on UGT1A1 mediated bilirubin-O-glucuronidation in HLM is much higher than that of entacapone. Furthermore, the potential risks of tolcapone or entacapone via inhibition of human UGT1A1 were quantitatively predicted by the ratio of the areas under the plasma drug concentration-time curve (AUC). The results indicate that tolcapone may result in significant increase in AUC of bilirubin or the drugs primarily metabolized by UGT1A1, while entacapone is unlikely to cause a significant DDI through inhibition of UGT1A1. - Highlights: • Tolcapone and entacapone exhibited preferential inhibition against UGT1A enzymes. • In contrast to entacapone, tolcapone exhibited more potent inhibitory effects on human UGT1A1, 1 A7 and 1 A10. • Tolcapone may lead to significant increase in AUC of bilirubin. �

Inhibition of human UDP-glucuronosyltransferase enzymes by lapatinib, pazopanib, regorafenib and sorafenib: Implications for hyperbilirubinemia.

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Miners, John O; Chau, Nuy; Rowland, Andrew; Burns, Kushari; McKinnon, Ross A; Mackenzie, Peter I; Tucker, Geoffrey T; Knights, Kathleen M; Kichenadasse, Ganessan

2017-04-01

Kinase inhibitors (KIs) are a rapidly expanding class of drugs used primarily for the treatment of cancer. Data relating to the inhibition of UDP-glucuronosyltransferase (UGT) enzymes by KIs is sparse. However, lapatinib (LAP), pazopanib (PAZ), regorafenib (REG) and sorafenib (SOR) have been implicated in the development of hyperbilirubinemia in patients. This study aimed to characterise the role of UGT1A1 inhibition in hyperbilirubinemia and assess the broader potential of these drugs to perpetrate drug-drug interactions arising from UGT enzyme inhibition. Twelve recombinant human UGTs from subfamilies 1A and 2B were screened for inhibition by LAP, PAZ, REG and SOR. IC 50 values for the inhibition of all UGT1A enzymes, except UGT1A3 and UGT1A4, by the four KIs were enzyme identified to date. In vitro-in vivo extrapolation indicates that inhibition of UGT1A1 contributes significantly to the hyperbilirubinemia observed in patients treated with REG and SOR, but not with LAP and PAZ. Inhibition of other UGT1A1 substrates in vivo is likely. Copyright © 2017 Elsevier Inc. All rights reserved.

Isolation and purification of rat liver morphine UDP-glucuronosyltransferase

International Nuclear Information System (INIS)

Puig, J.F.; Tephly, T.R.

1986-01-01

The enhancement of rat liver microsomal morphine (M) and 4-hydroxybiphenyl (4-HBP) UDP-glucuronyltransferase (UDPGT) activities by phenobarbital treatment has been proposed to represent increased activity of a single enzyme form, GT-2. They have separated M and 4-HBP UDPGT activities from Emulgen 911-solubilized microsomes obtained from livers of phenobarbital-treated Wistar rats. A sensitive assay procedure was developed to quantify M-UDPGT and 4-HBP-UDPGT activities using 14 C-UDP-glucuronic acid (UDPGA) and reversed phase C-18 minicolumns whereby the radioactive glucuronides were differentially eluted from labeled UDPGA. Trisacryl DEAE, and chromatofocusing procedures were employed to separate M-UDPGT and 4-HBP-UDPGT in the presence of exogenous phosphatidylcholine (PC). The PC is necessary to stabilize UDPGT activities. M-UDPGT was isolated to apparent homogeneity and displayed a monomeric molecular weight of 56,000 daltons on SDS-PAGE. It reacted with M but not with 4-HBP, bilirubin, p-nitrophenol, testosterone, androsterone, estrone, 4-aminobiphenyl or α-naphthylamine. 4-HBP-UDPGT did not react with M. Therefore, M and 4-HBP glucuronidations are catalyzed by separate enzymes in rat liver microsomes

Species differences in drug glucuronidation: Humanized UDP-glucuronosyltransferase 1 mice and their application for predicting drug glucuronidation and drug-induced toxicity in humans.

Science.gov (United States)

Fujiwara, Ryoichi; Yoda, Emiko; Tukey, Robert H

2018-02-01

More than 20% of clinically used drugs are glucuronidated by a microsomal enzyme UDP-glucuronosyltransferase (UGT). Inhibition or induction of UGT can result in an increase or decrease in blood drug concentration. To avoid drug-drug interactions and adverse drug reactions in individuals, therefore, it is important to understand whether UGTs are involved in metabolism of drugs and drug candidates. While most of glucuronides are inactive metabolites, acyl-glucuronides that are formed from compounds with a carboxylic acid group can be highly toxic. Animals such as mice and rats are widely used to predict drug metabolism and drug-induced toxicity in humans. However, there are marked species differences in the expression and function of drug-metabolizing enzymes including UGTs. To overcome the species differences, mice in which certain drug-metabolizing enzymes are humanized have been recently developed. Humanized UGT1 (hUGT1) mice were created in 2010 by crossing Ugt1-null mice with human UGT1 transgenic mice in a C57BL/6 background. hUGT1 mice can be promising tools to predict human drug glucuronidation and acyl-glucuronide-associated toxicity. In this review article, studies of drug metabolism and toxicity in the hUGT1 mice are summarized. We further discuss research and strategic directions to advance the understanding of drug glucuronidation in humans. Copyright © 2017 The Japanese Society for the Study of Xenobiotics. Published by Elsevier Ltd. All rights reserved.

Drug-Drug Interactions Potential of Icariin and Its Intestinal Metabolites via Inhibition of Intestinal UDP-Glucuronosyltransferases

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Yun-Feng Cao

2012-01-01

Full Text Available Icariin is known as an indicative constituent of the Epimedium genus, which has been commonly used in Chinese herbal medicine to enhance treat impotence and improve sexual function, as well as for several other indications for over 2000 years. In this study, we aimed to investigate the effects of icariin and its intestinal metabolites on the activities of human UDP-glucuronosyltransferase (UGT activities. Using a panel of recombinant human UGT isoforms, we found that icariin exhibited potent inhibition against UGT1A3. It is interesting that the intestinal metabolites of icariin exhibited a different inhibition profile compared with icariin. Different from icariin, icariside II was a potent inhibitor of UGT1A4, UGT1A7, UGT1A9, and UGT2B7, and icaritin was a potent inhibitor of UGT1A7 and UGT1A9. The potential for drug interactions in vivo was also quantitatively predicted and compared. The quantitative prediction of risks indicated that in vivo inhibition against intestinal UGT1A3, UGT1A4, and UGT1A7 would likely occur after oral administration of icariin products.

Comparison of inhibition capability of scutellarein and scutellarin towards important liver UDP-glucuronosyltransferase (UGT) isoforms.

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Ma, Guang-You; Cao, Yun-Feng; Hu, Cui-Min; Fang, Zhong-Ze; Sun, Xiao-Yu; Hong, Mo; Zhu, Zhi-Tu

2014-03-01

Scutellarin is an important bioactive flavonoid extracted from Erigeron breviscapus (Vant.) Hand-Mazz, and scutellarein is the corresponding aglycone of scutellarin. The present study aims to compare the inhibition potential of scutellarin and scutellarein towards several important UDP-glucuronosyltransferase (UGT) isoforms, including UGT1A1, UGT1A6, UGT1A9 and UGT2B7. It was demonstrated that scutellarein exerted stronger inhibition towards the tested UGT isoforms than scutellarin. Furthermore, the inhibition kinetic type and parameters (Ki ) were determined for the scutellarein's inhibition towards these UGT isoforms. Competitive inhibition of scutellarein towards all these UGT isoforms was demonstrated, and the Ki values were calculated to be 0.02, 5.0, 5.8 and 35.9 μM for UGT1A1, 1A6, 1A9 and 2B7, respectively. Using in vivo maximum plasma concentration of scutellarein in rat, the in vitro-in vivo extrapolation was performed to predict in vivo situation, indicating the most possible in vivo adverse effects due to the inhibition of scutellarein towards UGT1A1. All these results remind us to monitor the utilization of scutellarin and scutellarein, and the herbs containing these two components. Copyright © 2013 John Wiley & Sons, Ltd.

The UDP-glucuronosyltransferases of the blood-brain barrier: their role in drug metabolism and detoxication

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Mohamed eOuzzine

2014-10-01

Full Text Available UDP-glucuronosyltransferases (UGTs form a multigenic family of membrane-bound enzymes expressed in various tissues, including brain. They catalyze the formation of β-Dglucuronides from structurally unrelated substances (drugs, other xenobiotics, as well as endogenous compounds by the linkage of glucuronic acid from the high energy donor, UDP-αD-glucuronic acid. In brain, UGTs actively participate to the overall protection of the tissue against the intrusion of potentially harmful lipophilic substances that are metabolized as hydrophilic glucuronides. These metabolites are generally inactive, except for important pharmacologically glucuronides such as morphine-6-glucuronide. UGTs are mainly expressed in endothelial cells and astrocytes of the blood brain barrier. They are also associated to brain interfaces devoid of blood-brain barrier, such as circumventricular organ, pineal gland, pituitary gland and neuro-olfactory tissues. Beside their key-role as a detoxication barrier, UGTs play a role in the steady-state of endogenous compounds, like steroids or dopamine that participate to the function of the brain. UGT isoforms of family 1A, 2A, 2B and 3A are expressed in brain tissues to various levels and are known to present distinct but overlapping substrate specificity. The importance of these enzyme species with regard to the formation of toxic, pharmacologically or physiologically relevant glucuronides in the brain will be discussed.

Association of serum bilirubin and promoter variations in HMOX1 and UGT1A1 genes with sporadic colorectal cancer

Czech Academy of Sciences Publication Activity Database

Jirásková, A.; Novotný, J.; Novotný, L.; Vodička, Pavel; Pardini, Barbara; Naccarati, Alessio; Schwertner, H. A.; Hubáček, J. A.; Punčochářová, L.; Šmerhovský, Z.; Vítek, L.

2012-01-01

Roč. 131, č. 7 (2012), s. 1549-1555 ISSN 0020-7136 R&D Projects: GA ČR GA310/07/1430 Grant - others:GA MŠk(CZ) ME849; GA MŠk(CZ) 2B06155; GA MŠk(CZ) LH11030 Program:2B Institutional research plan: CEZ:AV0Z50390703 Keywords : bilirubin * bilirubin UDP-glucuronosyl transferase * colorectal cancer Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 6.198, year: 2012

Inhibition of UDP-Glucuronosyltransferase (UGT) Isoforms by Arctiin and Arctigenin.

Science.gov (United States)

Zhang, Hui; Zhao, Zhenying; Wang, Tao; Wang, Yijia; Cui, Xiao; Zhang, Huijuan; Fang, Zhong-Ze

2016-07-01

Arctiin is the major pharmacological ingredient of Fructus Arctii, and arctigenin is the metabolite of arctiin formed via the catalysis of human intestinal bacteria. The present study aims to investigate the inhibition profile of arctiin and arctigenin on important phase II drug-metabolizing enzymes UDP-glucuronosyltransferases (UGTs), indicating the possible herb-drug interaction. In vitro screening experiment showed that 100 μM of arctiin and arctigenin inhibited the activity of UGT1A3, 1A9, 2B7, and 2B15. Homology modeling-based in silico docking of arctiin and arctigenin into the activity cavity of UGT2B15 showed that hydrogen bonds and hydrophobic interactions contributed to the strong binding free energy of arctiin (-8.14 kcal/mol) and arctigenin (-8.43 kcal/mol) with UGT2B15. Inhibition kinetics study showed that arctiin and arctigenin exerted competitive and noncompetitive inhibition toward UGT2B15, respectively. The inhibition kinetic parameters (Ki ) were calculated to be 16.0 and 76.7 μM for the inhibition of UGT2B15 by arctiin and arctigenin, respectively. Based on the plasma concentration of arctiin and arctigenin after administration of 100 mg/kg of arctiin, the [I]/Ki values were calculated to be 0.3 and 0.007 for arctiin and arctigenin, respectively. Based on the inhibition evaluation standard ([I]/Ki   1, high possibility), arctiin might induce drug-drug interaction with medium possibility. Based on these results, clinical monitoring the utilization of Fructus Arctii is very important and necessary. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Effects of aqueous extract of Ruta graveolens and its ingredients on cytochrome P450, uridine diphosphate (UDP-glucuronosyltransferase, and reduced nicotinamide adenine dinucleotide (phosphate (NAD(PH-quinone oxidoreductase in mice

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Yune-Fang Ueng

2015-09-01

Full Text Available Ruta graveolens (the common rue has been used for various therapeutic purposes, including relief of rheumatism and treatment of circulatory disorder. To elucidate the effects of rue on main drug-metabolizing enzymes, effects of an aqueous extract of the aerial part of rue and its ingredients on cytochrome P450 (P450/CYP, uridine diphosphate (UDP-glucuronosyltransferase, and reduced nicotinamide adenine dinucleotide (phosphate (NAD(PH:quinone oxidoreductase were studied in C57BL/6JNarl mice. Oral administration of rue extract to males increased hepatic Cyp1a and Cyp2b activities in a dose-dependent manner. Under a 7-day treatment regimen, rue extract (0.5 g/kg induced hepatic Cyp1a and Cyp2b activities and protein levels in males and females. This treatment increased hepatic UDP-glucuronosyltransferase activity only in males. However, NAD(PH:quinone oxidoreductase activity remained unchanged. Based on the contents of rutin and furanocoumarins of mouse dose of rue extract, rutin increased hepatic Cyp1a activity and the mixture of furanocoumarins (Fmix increased Cyp2b activities in males. The mixture of rutin and Fmix increased Cyp1a and Cyp2b activities. These results revealed that rutin and Fmix contributed at least in part to the P450 induction by rue.

Relation of Transcriptional Factors to the Expression and Activity of Cytochrome P450 and UDP-Glucuronosyltransferases 1A in Human Liver: Co-Expression Network Analysis.

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Zhong, Shilong; Han, Weichao; Hou, Chuqi; Liu, Junjin; Wu, Lili; Liu, Menghua; Liang, Zhi; Lin, Haoming; Zhou, Lili; Liu, Shuwen; Tang, Lan

2017-01-01

Cytochrome P450 (CYPs) and UDP-glucuronosyltransferases (UGTs) play important roles in the metabolism of exogenous and endogenous compounds. The gene transcription of CYPs and UGTs can be enhanced or reduced by transcription factors (TFs). This study aims to explore novel TFs involved in the regulatory network of human hepatic UGTs/CYPs. Correlations between the transcription levels of 683 key TFs and CYPs/UGTs in three different human liver expression profiles (n = 640) were calculated first. Supervised weighted correlation network analysis (sWGCNA) was employed to define hub genes among the selected TFs. The relationship among 17 defined TFs, CYPs/UGTs expression, and activity were evaluated in 30 liver samples from Chinese patients. The positive controls (e.g., PPARA, NR1I2, NR1I3) and hub TFs (NFIA, NR3C2, and AR) in the Grey sWGCNA Module were significantly and positively associated with CYPs/UGTs expression. And the cancer- or inflammation-related TFs (TEAD4, NFKB2, and NFKB1) were negatively associated with mRNA expression of CYP2C9/CYP2E1/UGT1A9. Furthermore, the effect of NR1I2, NR1I3, AR, TEAD4, and NFKB2 on CYP450/UGT1A gene transcription translated into moderate influences on enzyme activities. To our knowledge, this is the first study to integrate Gene Expression Omnibus (GEO) datasets and supervised weighted correlation network analysis (sWGCNA) for defining TFs potentially related to CYPs/UGTs. We detected several novel TFs involved in the regulatory network of hepatic CYPs and UGTs in humans. Further validation and investigation may reveal their exact mechanism of CYPs/UGTs regulation.

Enzymatic conversion of bilirubin monoglucuronide to diglucuronide by rat liver plasma membranes

NARCIS (Netherlands)

Jansen, P. L.; Chowdhury, J. R.; Fischberg, E. B.; Arias, I. M.

1977-01-01

Formation of bilirubin monoglucuronide from unconjugated bilirubin requires a microsomal enzyme, UDP-glucuronate glucuronyltransferase (EC 2.4.1.17). Conversion of bilirubin monoglucuronide to bilirubin diglucuronide, the major bilirubin conjugate in bile, was studied in subcellular fractions of rat

Structures of bilirubin conjugates synthesized in vitro from bilirubin and uridine diphosphate glucuronic acid, uridine diphosphate glucose or uridine diphosphate xylose by preparations from rat liver

NARCIS (Netherlands)

Fevery, J.; Leroy, P.; van de Vijver, M.; Heirwegh, K. P.

1972-01-01

1. In incubation mixtures containing digitonin-activated or untreated preparations from rat liver, albumin-solubilized bilirubin as the acceptor substrate and (a) UDP-glucuronic acid, (b) UDP-glucose or (c) UDP-xylose as the sugar donor, formation of the following ester glycosides was demonstrated:

Androgen receptor signals regulate UDP-glucuronosyltransferases in the urinary bladder: a potential mechanism of androgen-induced bladder carcinogenesis.

Science.gov (United States)

Izumi, Koji; Zheng, Yichun; Hsu, Jong-Wei; Chang, Chawnshang; Miyamoto, Hiroshi

2013-02-01

UDP-glucuronosyltransferases (UGTs), major phase II drug metabolism enzymes, play an important role in urinary bladder cancer initiation by detoxifying carcinogens. We aimed to determine if androgens regulate UGT expression via the androgen receptor (AR) pathway in the bladder. Real-time reverse transcription-polymerase chain reaction and Western blot analyses were used to assess UGT1A levels in the normal urothelium SVHUC cell line stably expressed with AR and in bladder tissues from AR knockout (ARKO) and castrated male mice. Immunohistochemistry was also performed in radical cystectomy specimens. Dihydrotestosterone (DHT) treatment in SVHUC-AR reduced mRNA expression of all the UGT1A subtypes (19-75% decrease), and hydroxyflutamide antagonized the DHT effects. In contrast, DHT showed only marginal effects on UGT1A expression in SVHUC-Vector. Of note were higher expression levels of UGT1As in SVHUC-Vector than in SVHUC-AR. In ARKO mice, all the Ugt1a subtypes were up-regulated, compared to wild-type littermates. In wild-type male mice, castration increased the expression of Ugt1a8, Ugt1a9, and Ugt1a10. Additionally, wild-type female mice had higher levels of Ugt1a than wild-type males. Immunohistochemical studies showed strong (3+) UGT1A staining in 11/24 (46%) cancer tissues, which was significantly lower than in corresponding benign tissues [17/18 (94%) cases (P = 0.0009)]. These results suggest that androgen-mediated AR signals promote bladder carcinogenesis by down-regulating the expression of UGTs in the bladder. Copyright © 2011 Wiley Periodicals, Inc.

UDP-Glucuronosyltransferase Expression in Mouse Liver Is Increased in Obesity- and Fasting-Induced Steatosis

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Xu, Jialin; Kulkarni, Supriya R.; Li, Liya

2012-01-01

UDP-glucuronosyltransferases (Ugt) catalyze phase II conjugation reactions with glucuronic acid, which enhances chemical polarity and the elimination from the body. Few studies have addressed whether Ugt expression and activity are affected by liver disease, such as steatosis. The purpose of this study was to determine whether steatosis induced by obesity or fasting could affect liver Ugt mRNA expression and activity. Male C57BL/6J and Lepob/ob (ob/ob) mice were fed ad libitum or food was withheld for 24 h. In steatotic livers of ob/ob mice, Ugt1a1, -1a6, -1a9, -2a3, -3a1, and -3a2 mRNA expression increased. Fasting, which also induced steatosis, increased hepatic Ugt1a1, -1a6, -1a7, -1a9, -2b1, -2b5, -2a3, -3a1, and -3a2 mRNA expression in mouse liver. Likewise, acetaminophen glucuronidation increased by 47% in hepatic microsomes from ob/ob mice compared with that in C57BL/6J mice, but not after fasting. In both steatosis models, Ugt induction was accompanied by increased aryl hydrocarbon receptor, constitutive androstane receptor (CAR), peroxisome proliferator-activated receptor (PPAR)-α, pregnane X receptor, nuclear factor (erythroid-derived 2)-like 2 (Nrf2), and peroxisome proliferator-activated receptor-γ coactivator-1α mRNA expression. In addition, fasting increased CAR, PPAR, and Nrf2 binding activity. The work points to hepatic triglyceride concentrations corresponding with nuclear receptor and Ugt expression. The findings indicate that steatosis significantly alters hepatic Ugt expression and activity, which could have a significant impact on determining circulating hormone levels, drug efficacy, and environmental chemical clearance. PMID:22031624

UDP-glucuronosyltransferase expression in mouse liver is increased in obesity- and fasting-induced steatosis.

Science.gov (United States)

Xu, Jialin; Kulkarni, Supriya R; Li, Liya; Slitt, Angela L

2012-02-01

UDP-glucuronosyltransferases (Ugt) catalyze phase II conjugation reactions with glucuronic acid, which enhances chemical polarity and the elimination from the body. Few studies have addressed whether Ugt expression and activity are affected by liver disease, such as steatosis. The purpose of this study was to determine whether steatosis induced by obesity or fasting could affect liver Ugt mRNA expression and activity. Male C57BL/6J and Lep(ob/ob) (ob/ob) mice were fed ad libitum or food was withheld for 24 h. In steatotic livers of ob/ob mice, Ugt1a1, -1a6, -1a9, -2a3, -3a1, and -3a2 mRNA expression increased. Fasting, which also induced steatosis, increased hepatic Ugt1a1, -1a6, -1a7, -1a9, -2b1, -2b5, -2a3, -3a1, and -3a2 mRNA expression in mouse liver. Likewise, acetaminophen glucuronidation increased by 47% in hepatic microsomes from ob/ob mice compared with that in C57BL/6J mice, but not after fasting. In both steatosis models, Ugt induction was accompanied by increased aryl hydrocarbon receptor, constitutive androstane receptor (CAR), peroxisome proliferator-activated receptor (PPAR)-α, pregnane X receptor, nuclear factor (erythroid-derived 2)-like 2 (Nrf2), and peroxisome proliferator-activated receptor-γ coactivator-1α mRNA expression. In addition, fasting increased CAR, PPAR, and Nrf2 binding activity. The work points to hepatic triglyceride concentrations corresponding with nuclear receptor and Ugt expression. The findings indicate that steatosis significantly alters hepatic Ugt expression and activity, which could have a significant impact on determining circulating hormone levels, drug efficacy, and environmental chemical clearance.

Photoaffinity labeling of rat liver microsomal morphine UDP-glucuronosyltransferase by ( sup 3 H)flunitrazepam

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Thomassin, J.; Tephly, T.R. (Univ. of Iowa, Iowa City (USA))

1990-09-01

Benzodiazepines have been shown to competitively inhibit morphine glucuronidation in rat and human hepatic microsomes. Flunitrazepam exerted a potent competitive inhibition of rat hepatic morphine UDP-glucuronosyltransferase (UDPGT) activity (Ki = 130 microM). It has no effect on the activity of p-nitrophenol, 17 beta-hydroxysteroid, 3 alpha-hydroxysteroid, or 4-hydroxybiphenyl UDPGTs. Because flunitrazepam is an effective photoaffinity label for benzodiazepine receptors, studied were performed in solubilized rat hepatic microsomes and with partially purified preparations of morphine UDPGT to determine the enhancement of flunitrazepam inhibition and binding to morphine UDPGT promoted by exposure to UV light. Under UV light, flunitrazepam inhibition was markedly enhanced. UV light exposure also led to a marked increase in binding of (3H)flunitrazepam to microsomal protein, which was protected substantially by preincubation with morphine. Testosterone, androsterone, and UDP-glucuronic acid did not protect against UV-enhanced flunitrazepam binding, and morphine did not reverse flunitrazepam binding once binding had occurred. As morphine UDPGT was purified, a good correlation was found between the increases in specific activity of morphine UDPGT and flunitrazepam binding to protein. Chromatofocusing chromatography showed that flunitrazepam bound only to fractions containing active morphine UDPGT, and no binding to 4-hydroxybiphenyl UDPGT was observed. Fluorography of a sodium dodecyl sulfate-polyacrylamide electrophoresis gel of solubilized hepatic microsomes that had been treated with (3H) flunitrazepam under UV light revealed a band with a monomeric molecular weight between 54,000 and 58,000. This monomeric molecular weight compares favorably with the reported monomeric molecular weight of homogeneous morphine UDPGT (56,000).

Hepatic Metabolism of Sakuranetin and Its Modulating Effects on Cytochrome P450s and UDP-Glucuronosyltransferases

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Hyesoo Jeong

2018-06-01

Full Text Available Sakuranetin (SKN, found in cherry trees and rice, is a flavanone with various pharmacological activities. It is biosynthesized from naringenin in rice or cherry trees, and the metabolism of SKN has been studied in non-human species. The present study aimed to investigate the metabolic pathways of SKN in human liver microsomes and identify the phase I and phase II metabolites, as well as evaluate the potential for drug–herb interactions through the modulation of drug metabolizing enzymes (DMEs. HPLC-DAD and HPLC-electrospray mass spectrometry were used to study the metabolic stability and identify the metabolites from human liver microsomes incubated with SKN. The potential of SKN to inhibit the DMEs was evaluated by monitoring the formation of a DME-specific product. The cytochrome P450 2B6 and 3A4-inductive effects were studied using promoter reporter assays in human hepatocarcinoma cells. The major pathways for SKN metabolism include B-ring hydroxylation, 5-O-demethylation, and conjugation with glutathione or glucuronic acid. The phase I metabolites were identified as naringenin and eriodictyol. SKN was found to be a UDP-glucuronosyltransferases (UGT 1A9 inhibitor, whereas it induced transactivation of the human pregnane X receptor-mediated cytochrome P450 (CYP 3A4 gene.

Bilirubin glucuronidation revisited: proper assay conditions to estimate enzyme kinetics with recombinant UGT1A1.

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

2010-11-01

Bilirubin, an end product of heme catabolism, is primarily eliminated via glucuronic acid conjugation by UGT1A1. Impaired bilirubin conjugation, caused by inhibition of UGT1A1, can result in clinical consequences, including jaundice and kernicterus. Thus, evaluation of the ability of new drug candidates to inhibit UGT1A1-catalyzed bilirubin glucuronidation in vitro has become common practice. However, the instability of bilirubin and its glucuronides presents substantial technical challenges to conduct in vitro bilirubin glucuronidation assays. Furthermore, because bilirubin can be diglucuronidated through a sequential reaction, establishment of initial rate conditions can be problematic. To address these issues, a robust high-performance liquid chromatography assay to measure both bilirubin mono- and diglucuronide conjugates was developed, and the incubation conditions for bilirubin glucuronidation by human embryonic kidney 293-expressed UGT1A1 were carefully characterized. Our results indicated that bilirubin glucuronidation should be assessed at very low protein concentrations (0.05 mg/ml protein) and over a short incubation time (5 min) to assure initial rate conditions. Under these conditions, bilirubin total glucuronide formation exhibited a hyperbolic (Michaelis-Menten) kinetic profile with a K(m) of ∼0.2 μM. In addition, under these initial rate conditions, the relative proportions between the total monoglucuronide and the diglucuronide product were constant across the range of bilirubin concentration evaluated (0.05-2 μM), with the monoglucuronide being the predominant species (∼70%). In conclusion, establishment of appropriate incubation conditions (i.e., very low protein concentrations and short incubation times) is necessary to properly characterize the kinetics of bilirubin glucuronidation in a recombinant UGT1A1 system.

Quantitative Characterization of Major Hepatic UDP-Glucuronosyltransferase Enzymes in Human Liver Microsomes: Comparison of Two Proteomic Methods and Correlation with Catalytic Activity.

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Achour, Brahim; Dantonio, Alyssa; Niosi, Mark; Novak, Jonathan J; Fallon, John K; Barber, Jill; Smith, Philip C; Rostami-Hodjegan, Amin; Goosen, Theunis C

2017-10-01

Quantitative characterization of UDP-glucuronosyltransferase (UGT) enzymes is valuable in glucuronidation reaction phenotyping, predicting metabolic clearance and drug-drug interactions using extrapolation exercises based on pharmacokinetic modeling. Different quantitative proteomic workflows have been employed to quantify UGT enzymes in various systems, with reports indicating large variability in expression, which cannot be explained by interindividual variability alone. To evaluate the effect of methodological differences on end-point UGT abundance quantification, eight UGT enzymes were quantified in 24 matched liver microsomal samples by two laboratories using stable isotope-labeled (SIL) peptides or quantitative concatemer (QconCAT) standard, and measurements were assessed against catalytic activity in seven enzymes ( n = 59). There was little agreement between individual abundance levels reported by the two methods; only UGT1A1 showed strong correlation [Spearman rank order correlation (Rs) = 0.73, P quantitative proteomic data should be validated against catalytic activity whenever possible. In addition, metabolic reaction phenotyping exercises should consider spurious abundance-activity correlations to avoid misleading conclusions. Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.

UDP-glucuronosyltransferase and sulfotransferase polymorphisms, sex hormone concentrations, and tumor receptor status in breast cancer patients

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Sparks, Rachel; Yuan, Xiaopu; Lin, Ming Gang; McVarish, Lynda; Aiello, Erin J; McTiernan, Anne; Ulrich, Cornelia M; Bigler, Jeannette; Tworoger, Shelley S; Yasui, Yutaka; Rajan, Kumar B; Porter, Peggy; Stanczyk, Frank Z; Ballard-Barbash, Rachel

2004-01-01

UDP-glucuronosyltransferase (UGT) and sulfotransferase (SULT) enzymes are involved in removing sex hormones from circulation. Polymorphic variation in five UGT and SULT genes – UGT1A1 ((TA) 6 /(TA) 7 ), UGT2B4 (Asp 458 Glu), UGT2B7 (His 268 Tyr), UGT2B15 (Asp 85 Tyr), and SULT1A1 (Arg 213 His) – may be associated with circulating sex hormone concentrations, or the risk of an estrogen receptor-negative (ER - ) or progesterone receptor-negative (PR - ) tumor. Logistic regression analysis was used to estimate the odds ratios of an ER - or PR - tumor associated with polymorphisms in the genes listed above for 163 breast cancer patients from a population-based cohort study of women in western Washington. Adjusted geometric mean estradiol, estrone, and testosterone concentrations were calculated within each UGT and SULT genotype for a subpopulation of postmenopausal breast cancer patients not on hormone therapy 2–3 years after diagnosis (n = 89). The variant allele of UGT1A1 was associated with reduced risk of an ER - tumor (P for trend = 0.03), and variants of UGT2B15 and SULT1A1 were associated with non-statistically significant risk reductions. There was some indication that plasma estradiol and testosterone concentrations varied by UGT2B15 and SULT1A1 genotypes; women with the UGT2B15 Asp/Tyr and Tyr/Tyr genotypes had higher concentrations of estradiol than women with the Asp/Asp genotype (P = 0.004). Compared with women with the SULT1A1 Arg/Arg and Arg/His genotypes, women with the His/His genotype had elevated concentrations of testosterone (P = 0.003). The risk of ER - breast cancer tumors may vary by UGT or SULT genotype. Further, plasma estradiol and testosterone concentrations in breast cancer patients may differ depending on some UGT and SULT genotypes

Disturbance of Mammary UDP-Glucuronosyltransferase Represses Estrogen Metabolism and Exacerbates Experimental Breast Cancer.

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Zhou, Xueyan; Zheng, Ziqiang; Xu, Chang; Wang, Juan; Min, Mengjun; Zhao, Yun; Wang, Xi; Gong, Yinhan; Yin, Jiale; Guo, Meng; Guo, Dong; Zheng, Junnian; Zhang, Bei; Yin, Xiaoxing

2017-08-01

The progression of breast cancer is closely related to the levels of estrogens within the body. UDP-glucuronosyltransferase (UGT) is an important class of phase II metabolizing enzymes, playing a pivotal role in detoxifying steroid hormone. In the present study, we aim at uncovering the potential dysregulation pattern of UGT and its role in estrogen metabolism and in the pathogenesis of breast cancer. Female Sprague-Dawley rats were treated with 100 mg/kg dimethylbenz(a)anthracene (DMBA) to induce breast cancer. Our results showed that the expression and activity of UGT in mammary tissues were downregulated significantly in DMBA rats. Consistent with this, levels of estradiol, 4-hydroxylated estradiol, and 2-hydroxylated estradiol were increased in both mammary tissues and serum, supporting a notable accumulation of toxic estrogen species in the target tissue of breast cancer. In addition, we also observed the decreased cell migration, cell proliferation, and DNA damage in UGT-transfected MCF-7 cells, suggesting a protective role of UGT against estrogen-induced mammary carcinogenesis. Taken together, these results indicated that accumulation of estrogens induced by UGT deficiency is a critical factor to induce the development of breast cancer. UGT contributes to estrogen elimination, and its glucuronidation capacity influences the estrogen signaling pathway and the pathogenesis of breast cancer. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Binding of bilirubin and its structural analogues to hepatic microsomal bilirubin UDP glucuronyltransferase

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Vanstapel, F.; Blanckaert, N.

1987-01-01

Hepatic glucuronidation of the asymmetrical natural bilirubin molecule results in formation of two different positional isomers, bilirubin C-8 monoglucuronide and bilirubin C-12 monoglucuronide. In view of the existence of multiple isoforms of UDPglucuronyltransferase, which is the microsomal enzyme system responsible for bilirubin esterification, the authors performed kinetic analysis of microsomal glucuronidation of bilirubin and a number of its structural congeners to determine whether synthesis of the two monoglucuronide isomers involved two distinct substrate-binding sites or reflected two different modes of binding to a single catalytic site. Both isomers were found in all tested species (man, rat, guinea pig, sheep), but there were marked species differences in the C-8/C-12 ratio of monoglucuronide found in bile or formed by liver microsomes. Correspondence between in vivo and in vitro results for such regioselectivity of glucuronidation was excellent in each species. On the basis of these results of kinetic analysis of bilirubin esterification at variable pigment substrate concentrations and inhibition studies with alternative substrates, the authors postulate that both natural monoglucuronide isomers are synthesized at a single binding site. Possible mechanisms responsible for the markedly regioselective esterification of bilirubin by rat and sheep liver were investigated by study of glucuronidation of selected structural analgoues of the pigment. Collectively, their findings suggest that the molecular from(s) of bilirubin able to engage in catalytically effective binding to UDPglucuronyltransferase does (do) not correspond with intramolecularly hydrogen-bonded conformers and that the nature of the β-substituents of the outer pyrromethenone rings is a key determinant of glucuronidation rate

Predictive effects of bilirubin on response of colorectal cancer to irinotecan-based chemotherapy.

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Yu, Qian-Qian; Qiu, Hong; Zhang, Ming-Sheng; Hu, Guang-Yuan; Liu, Bo; Huang, Liu; Liao, Xin; Li, Qian-Xia; Li, Zhi-Huan; Yuan, Xiang-Lin

2016-04-28

To examine the predictive effects of baseline serum bilirubin levels and UDP-glucuronosyltransferase (UGT) 1A1*28 polymorphism on response of colorectal cancer to irinotecan-based chemotherapy. The present study was based on a prospective multicenter longitudinal trial of Chinese metastatic colorectal cancer (mCRC) patients treated with irinotecan-based chemotherapy (NCT01282658). Baseline serum bilirubin levels, including total bilirubin (TBil) and unconjugated bilirubin (UBil), were measured, and genotyping of UGT1A1*28 polymorphism was performed. Receiver operating characteristic curve (ROC) analysis was used to determine cutoff values of TBil and UBil. The TBil values were categorized into > 13.0 or ≤ 13.0 groups; the UBil values were categorized into > 4.1 or ≤ 4.1 groups. Combining the cutoff values of TBil and UBil, which was recorded as CoBil, patients were classified into three groups. The classifier's performance of UGT1A1*28 and CoBil for predicting treatment response was evaluated by ROC analysis. Associations between response and CoBil or UGT1A1*28 polymorphism were estimated using simple and multiple logistic regression models. Among the 120 mCRC patients, the serum bilirubin level was significantly different between the UGT1A1*28 wild-type and mutant genotypes. Patients with the mutant genotype had an increased likelihood of a higher TBil (P = 0.018) and a higher UBil (P = 0.014) level compared with the wild-type genotype. Patients were stratified into three groups based on CoBil. Group 1 was patients with TBil > 13.0 and UBil > 4.1; Group 2 was patients with TBil ≤ 13.0 and UBil > 4.1; and Group 3 was patients with TBil ≤ 13.0 and UBil ≤ 4.1. Patients in Group 3 had more than a 10-fold higher likelihood of having a response in the simple (OR = 11.250; 95%CI: 2.286-55.367; P = 0.003) and multiple (OR = 16.001; 95%CI: 2.802 -91.371; P = 0.002) analyses compared with the Group 1 individuals. Patients carrying the UGT1A1*28 (TA)7 allele were 4

Herb-drug interaction prediction based on the high specific inhibition of andrographolide derivatives towards UDP-glucuronosyltransferase (UGT) 2B7.

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Ma, Hai-Ying; Sun, Dong-Xue; Cao, Yun-Feng; Ai, Chun-Zhi; Qu, Yan-Qing; Hu, Cui-Min; Jiang, Changtao; Dong, Pei-Pei; Sun, Xiao-Yu; Hong, Mo; Tanaka, Naoki; Gonzalez, Frank J; Ma, Xiao-Chi; Fang, Zhong-Ze

2014-05-15

Herb-drug interaction strongly limits the clinical application of herbs and drugs, and the inhibition of herbal components towards important drug-metabolizing enzymes (DMEs) has been regarded as one of the most important reasons. The present study aims to investigate the inhibition potential of andrographolide derivatives towards one of the most important phase II DMEs UDP-glucuronosyltransferases (UGTs). Recombinant UGT isoforms (except UGT1A4)-catalyzed 4-methylumbelliferone (4-MU) glucuronidation reaction and UGT1A4-catalyzed trifluoperazine (TFP) glucuronidation were employed to firstly screen the andrographolide derivatives' inhibition potential. High specific inhibition of andrographolide derivatives towards UGT2B7 was observed. The inhibition type and parameters (Ki) were determined for the compounds exhibiting strong inhibition capability towards UGT2B7, and human liver microsome (HLMs)-catalyzed zidovudine (AZT) glucuronidation probe reaction was used to furtherly confirm the inhibition behavior. In combination of inhibition parameters (Ki) and in vivo concentration of andrographolide and dehydroandrographolide, the potential in vivo inhibition magnitude was predicted. Additionally, both the in vitro inhibition data and computational modeling results provide important information for the modification of andrographolide derivatives as selective inhibitors of UGT2B7. Taken together, data obtained from the present study indicated the potential herb-drug interaction between Andrographis paniculata and the drugs mainly undergoing UGT2B7-catalyzed metabolic elimination, and the andrographolide derivatives as potential candidates for the selective inhibitors of UGT2B7. Copyright © 2014 Elsevier Inc. All rights reserved.

UDP-N-acetyl-α-D-glucosamine as acceptor substrate of β-1,4-galactosyltransferase : Enzymatic synthesis of UDP-N-acetyllactosamine

NARCIS (Netherlands)

Vliegenthart, J.F.G.; Elling, L.; Zervosen, A.; Gutiérrez Gallego, R.; Nieder, V.; Malissard, M.; Berger, E.G.; Kamerling, J.P.

1999-01-01

The capacity of UDP-N-acetyl-α-D-glucosamine (UDP-GlcNAc) as an in vitro acceptor substrate for β-1,4-galactosyltransferase (β4GalT1, EC 2.4.1.38) from human and bovine milk and for recombinant human β4GalT1, expressed in Saccharomyces cerevisiae, was evaluated. It turned out that each of the

Mangifera indica L. extract and mangiferin modulate cytochrome P450 and UDP-glucuronosyltransferase enzymes in primary cultures of human hepatocytes.

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Rodeiro, Idania; José Gómez-Lechón, M; Perez, Gabriela; Hernandez, Ivones; Herrera, José Alfredo; Delgado, Rene; Castell, José V; Teresa Donato, M

2013-05-01

The aqueous stem bark extract of Mangifera indica L. (MSBE) has been reported to have antioxidant, anti-inflammatory and analgesic properties. In previous studies, we showed that MSBE and mangiferin, its main component, lower the activity of some cytochrome P-450 (P450) enzymes in rat hepatocytes and human liver microsomes. In the present study, the effects of MSBE and mangiferin on several P450 enzymes and UDP-glucuronosyltransferases (UGTs) in human-cultured hepatocytes have been examined. After hepatocytes underwent a 48-h treatment with sub-cytotoxic concentrations of the products (50-250 µg/mL), a concentration-dependent decrease of the activity of the five P450 enzymes measured (CYP1A2, 2A6, 2C9, 2D6 and 3A4) was observed. For all the activities, a reduction of at least 50% at the highest concentration (250 µg/mL) was observed. In addition, UGT activities diminished. MSBE considerably reduced UGT1A9 activity (about 60% at 250 µg/mL) and lesser effects on the other UGTs. In contrast, 250 µg/mL mangiferin had greater effects on UGT1A1 and 2B7 than on UGT1A9 (about 55% vs. 35% reduction, respectively). Quantification of specific mRNAs revealed reduced CYP3A4 and 3A5 mRNAs content, and an increase in CYP1A1, CYP1A2, UGT1A1 and UGT1A9 mRNAs. No remarkable effects on the CYP2A6, 2B6, 2C9, 2C19, 2D6 and 2E1 levels were observed. Our results suggest that the activity and/or expression of major P450 and UGT enzymes is modulated by MSBE and that potential herb-drugs interactions could arise after a combined intake of this extract with conventional medicines. Therefore, the potential safety risks of this natural product derived by altering the ADMET properties of co-administered drugs should be examined. Copyright © 2012 John Wiley & Sons, Ltd.

Role of brain cytochrome P450 mono-oxygenases in bilirubin oxidation-specific induction and activity.

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Gambaro, Sabrina E; Robert, Maria C; Tiribelli, Claudio; Gazzin, Silvia

2016-02-01

In the Crigler-Najjar type I syndrome, the genetic absence of efficient hepatic glucuronidation of unconjugated bilirubin (UCB) by the uridine 5'-diphospho-glucuronosyltransferase1A1 (UGT1A1) enzyme produces the rise of UCB level in blood. Its entry to central nervous system could generate toxicity and neurological damage, and even death. In the past years, a compensatory mechanism to liver glucuronidation has been indicated in the hepatic cytochromes P450 enzymes (Cyps) which are able to oxidize bilirubin. Cyps are expressed also in the central nervous system, the target of bilirubin toxicity, thus making them theoretically important to confer a protective activity toward bilirubin accumulation and neurotoxicity. We therefore investigated the functional induction (mRNA, EROD/MROD) and the ability to oxidize bilirubin of Cyp1A1, 1A2, and 2A3 in primary astrocytes cultures obtained from two rat brain region (cortex: Cx and cerebellum: Cll). We observed that Cyp1A1 was the Cyp isoform more easily induced by beta-naphtoflavone (βNF) in both Cx and Cll astrocytes, but oxidized bilirubin only after uncoupling by 3, 4,3',4'-tetrachlorobiphenyl (TCB). On the contrary, Cyp1A2 was the most active Cyp in bilirubin clearance without uncoupling, but its induction was confined only in Cx cells. Brain Cyp2A3 was not inducible. In conclusion, the exposure of astrocytes to βNF plus TCB significantly enhanced Cyp1A1 mediating bilirubin clearance, improving cell viability in both regions. These results may be a relevant groundwork for the manipulation of brain Cyps as a therapeutic approach in reducing bilirubin-induced neurological damage.

Bilirubin Decreases Macrophage Cholesterol Efflux and ATP-Binding Cassette Transporter A1 Protein Expression.

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Wang, Dongdong; Tosevska, Anela; Heiß, Elke H; Ladurner, Angela; Mölzer, Christine; Wallner, Marlies; Bulmer, Andrew; Wagner, Karl-Heinz; Dirsch, Verena M; Atanasov, Atanas G

2017-04-28

Mild but chronically elevated circulating unconjugated bilirubin is associated with reduced total and low-density lipoprotein cholesterol concentration, which is associated with reduced cardiovascular disease risk. We aimed to investigate whether unconjugated bilirubin influences macrophage cholesterol efflux, as a potential mechanism for the altered circulating lipoprotein concentrations observed in hyperbilirubinemic individuals. Cholesterol efflux from THP-1 macrophages was assessed using plasma obtained from normo- and hyperbilirubinemic (Gilbert syndrome) humans (n=60 per group) or (heterozygote/homozygote Gunn) rats (n=20 per group) as an acceptor. Hyperbilirubinemic plasma from patients with Gilbert syndrome and Gunn rats induced significantly reduced cholesterol efflux compared with normobilirubinemic plasma. Unconjugated bilirubin (3-17.1 μmol/L) exogenously added to plasma- or apolipoprotein A1-supplemented media also decreased macrophage cholesterol efflux in a concentration- and time-dependent manner. We also showed reduced protein expression of the ATP-binding cassette transporter A1 (ABCA1), a transmembrane cholesterol transporter involved in apolipoprotein A1-mediated cholesterol efflux, in THP-1 macrophages treated with unconjugated bilirubin and in peripheral blood mononuclear cells obtained from hyperbilirubinemic individuals. Furthermore, we demonstrated that bilirubin accelerates the degradation rate of the ABCA1 protein in THP-1 macrophages. Cholesterol efflux from THP-1 macrophages is decreased in the presence of plasma obtained from humans and rats with mild hyperbilirubinemia. A direct effect of unconjugated bilirubin on cholesterol efflux was demonstrated and is associated with decreased ABCA1 protein expression. These data improve our knowledge concerning bilirubin's impact on cholesterol transport and represent an important advancement in our understanding of bilirubin's role in cardiovascular disease. © 2017 The Authors. Published on

Effect of a New Prokinetic Agent DA-9701 Formulated with Corydalis Tuber and Pharbitidis Semen on Cytochrome P450 and UDP-Glucuronosyltransferase Enzyme Activities in Human Liver Microsomes

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Hye Young Ji

2012-01-01

Full Text Available DA-9701 is a new botanical drug composed of the extracts of Corydalis tuber and Pharbitidis semen, and it is used as an oral therapy for the treatment of functional dyspepsia in Korea. The inhibitory potentials of DA-9701 and its component herbs, Corydalis tuber and Pharbitidis semen, on the activities of seven major human cytochrome P450 (CYP enzymes and four UDP-glucuronosyltransferase (UGT enzymes in human liver microsomes were investigated using liquid chromatography-tandem mass spectrometry. DA-9701 and Corydalis tuber extract slightly inhibited UGT1A1-mediated etoposide glucuronidation, with 50% inhibitory concentration (IC50 values of 188 and 290 μg/mL, respectively. DA-9701 inhibited CYP2D6-catalyzed bufuralol 1′-hydroxylation with an inhibition constant (Ki value of 6.3 μg/mL in a noncompetitive manner. Corydalis tuber extract competitively inhibited CYP2D6-mediated bufuralol 1′-hydroxylation, with a Ki value of 3.7 μg/mL, whereas Pharbitidis semen extract showed no inhibition. The volume in which the dose could be diluted to generate an IC50 equivalent concentration (volume per dose index value of DA-9701 for inhibition of CYP2D6 activity was 1.16 L/dose, indicating that DA-9701 may not be a potent CYP2D6 inhibitor. Further clinical studies are warranted to evaluate the in vivo extent of the observed in vitro interactions.

Enterohepatic circulation of nonconjugated bilirubin in rats fed with human milk

International Nuclear Information System (INIS)

Alonso, E.M.; Whitington, P.F.; Whitington, S.H.; Rivard, W.A.; Given, G.

1991-01-01

To test the hypothesis that enhanced intestinal absorption of bilirubin may contribute to prolonged nonconjugated hyperbilirubinemia in human milk-fed infants, we studied a cross-section of 36 healthy infants and mothers. Milk from mothers and serum from infants were collected at 16.3 +/- 2.4 days. Milk was studied for its effect on the absorption of bilirubin labeled with carbon 14 in rats and compared with buffer and iron-fortified infant formula (Similac With Iron). The percentage of a 1 mg bilirubin dose absorbed by the rat was 25.29 +/- 4.0% when it was administered into the duodenum with buffer, 4.67 +/- 2.4% with Similac formula, and 7.7 +/- 2.9% with human milk. Linear regression analysis, using the infant's serum nonconjugated bilirubin level as the dependent variable and the percentage of (14C)bilirubin absorbed by the rat with the corresponding mother's milk as the independent variable, revealed a significant correlation (r = 0.40; p = 0.016). Inspection of the data suggested that absorptive permissiveness correlated closely with infant serum bilirubin values greater than 24 mumol/L (1.4 mg/dl) (r = 0.55; p = 0.007), whereas in those with bilirubin values less than or equal to 24 mumol/L, there was no apparent correlation. Milk was also analyzed for beta-glucuronidase, nonesterified fatty acids, and the ability to inhibit glucuronosyltransferase activity of rat liver microsomes in vitro, none of which correlated with the infant's serum bilirubin. These data support the theory that enhanced intestinal absorption of bilirubin contributes to the jaundice associated with breast-feeding

Age-dependent Hepatic UDP-glucuronosyltransferase Gene Expression and Activity in Children

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Elizabeth Neumann

2016-11-01

Full Text Available ABSTRACTUDP-glucuronosyltransferases (UGTs are important phase II drug metabolism enzymes. The aim of this study was to explore the relationship between age and changes in mRNA expression and activity of major human hepatic UGTs, as well as to understand the potential regulatory mechanism underlying this relationship. Using previously generated data, we investigated age-dependent mRNA expression levels of 11 hepatic UGTs (UGT1A1, UGT1A3, UGT1A4, UGT1A5, UGT1A6, UGT1A9, UGT2B4, UGT2B7, UGT2B10, UGT2B15 and UGT2B17 and 16 transcription factors (AHR, AR, CAR, ESR2, FXR, GCCR, HNF1a, HNF3a, HNF3b, HNF4a, PPARA, PPARG, PPARGC, PXR, SP1, and STAT3 in liver tissue of donors (n = 38 ranging from 0 to 25 years of age. We also examined the correlation between age and microsomal activities using 14 known UGT drug substrates in the liver samples (n = 19 of children donors. We found a statistically significant increase (nominal p < 0.05 in the expression of UGT1A1, UGT1A3, UGT1A4, UGT1A5, UGT1A6, UGT2B7 and UGT2B17, as well as glucuronidation activities of serotonin, testosterone, and vorinostat during the first 25 years of life. Expression of estrogen receptor 1 (ESR1 and pregnane X receptor (PXR, two strong UGT transcriptional regulators, were significantly correlated with both age and UGT mRNA expression (p ≤ 0.05. These results suggest that both UGT expression and activity increase during childhood and adolescence, possibly driven in part by hormonal signaling. Our findings may help explain inter-patient variability in response to medications among children.

Herb–drug interaction prediction based on the high specific inhibition of andrographolide derivatives towards UDP-glucuronosyltransferase (UGT) 2B7

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Ma, Hai-Ying [The Fourth Affiliated Hospital of China Medical University, Shenyang 110032 (China); Sun, Dong-Xue [School of Traditional Chinese Medicine, Shenyang Pharmaceutical University, No. 103, Wenhua Road, Shenyang 110016 (China); Cao, Yun-Feng [The First Affiliated Hospital of Liaoning Medical University, Jinzhou 121001 (China); Joint Center for Translational Medicine, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road, Dalian 116023 (China); Ai, Chun-Zhi [Joint Center for Translational Medicine, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road, Dalian 116023 (China); Qu, Yan-Qing [Thyroid Surgery, Yantaishan Hospital, Yantai, Shandong (China); Hu, Cui-Min [Joint Center for Translational Medicine, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road, Dalian 116023 (China); Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC 20057 (United States); Jiang, Changtao [Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892 (United States); Dong, Pei-Pei [Academy of Integrative Medicine, Dalian Medical University, Dalian 116044 (China); Sun, Xiao-Yu; Hong, Mo [Joint Center for Translational Medicine, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road, Dalian 116023 (China); Tanaka, Naoki; Gonzalez, Frank J. [Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892 (United States); others, and

2014-05-15

Herb–drug interaction strongly limits the clinical application of herbs and drugs, and the inhibition of herbal components towards important drug-metabolizing enzymes (DMEs) has been regarded as one of the most important reasons. The present study aims to investigate the inhibition potential of andrographolide derivatives towards one of the most important phase II DMEs UDP-glucuronosyltransferases (UGTs). Recombinant UGT isoforms (except UGT1A4)-catalyzed 4-methylumbelliferone (4-MU) glucuronidation reaction and UGT1A4-catalyzed trifluoperazine (TFP) glucuronidation were employed to firstly screen the andrographolide derivatives' inhibition potential. High specific inhibition of andrographolide derivatives towards UGT2B7 was observed. The inhibition type and parameters (K{sub i}) were determined for the compounds exhibiting strong inhibition capability towards UGT2B7, and human liver microsome (HLMs)-catalyzed zidovudine (AZT) glucuronidation probe reaction was used to furtherly confirm the inhibition behavior. In combination of inhibition parameters (K{sub i}) and in vivo concentration of andrographolide and dehydroandrographolide, the potential in vivo inhibition magnitude was predicted. Additionally, both the in vitro inhibition data and computational modeling results provide important information for the modification of andrographolide derivatives as selective inhibitors of UGT2B7. Taken together, data obtained from the present study indicated the potential herb–drug interaction between Andrographis paniculata and the drugs mainly undergoing UGT2B7-catalyzed metabolic elimination, and the andrographolide derivatives as potential candidates for the selective inhibitors of UGT2B7. - Highlights: • Specific inhibition of andrographolide derivatives towards UGT2B7. • Herb-drug interaction related withAndrographis paniculata. • Guidance for design of UGT2B7 specific inhibitors.

Herb–drug interaction prediction based on the high specific inhibition of andrographolide derivatives towards UDP-glucuronosyltransferase (UGT) 2B7

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Ma, Hai-Ying; Sun, Dong-Xue; Cao, Yun-Feng; Ai, Chun-Zhi; Qu, Yan-Qing; Hu, Cui-Min; Jiang, Changtao; Dong, Pei-Pei; Sun, Xiao-Yu; Hong, Mo; Tanaka, Naoki; Gonzalez, Frank J.

2014-01-01

Herb–drug interaction strongly limits the clinical application of herbs and drugs, and the inhibition of herbal components towards important drug-metabolizing enzymes (DMEs) has been regarded as one of the most important reasons. The present study aims to investigate the inhibition potential of andrographolide derivatives towards one of the most important phase II DMEs UDP-glucuronosyltransferases (UGTs). Recombinant UGT isoforms (except UGT1A4)-catalyzed 4-methylumbelliferone (4-MU) glucuronidation reaction and UGT1A4-catalyzed trifluoperazine (TFP) glucuronidation were employed to firstly screen the andrographolide derivatives' inhibition potential. High specific inhibition of andrographolide derivatives towards UGT2B7 was observed. The inhibition type and parameters (K i ) were determined for the compounds exhibiting strong inhibition capability towards UGT2B7, and human liver microsome (HLMs)-catalyzed zidovudine (AZT) glucuronidation probe reaction was used to furtherly confirm the inhibition behavior. In combination of inhibition parameters (K i ) and in vivo concentration of andrographolide and dehydroandrographolide, the potential in vivo inhibition magnitude was predicted. Additionally, both the in vitro inhibition data and computational modeling results provide important information for the modification of andrographolide derivatives as selective inhibitors of UGT2B7. Taken together, data obtained from the present study indicated the potential herb–drug interaction between Andrographis paniculata and the drugs mainly undergoing UGT2B7-catalyzed metabolic elimination, and the andrographolide derivatives as potential candidates for the selective inhibitors of UGT2B7. - Highlights: • Specific inhibition of andrographolide derivatives towards UGT2B7. • Herb-drug interaction related withAndrographis paniculata. • Guidance for design of UGT2B7 specific inhibitors

Herb–drug interaction prediction based on the high specific inhibition of andrographolide derivatives towards UDP-glucuronosyltransferase (UGT) 2B7

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Ma, Hai-Ying, E-mail: cmu4h-mhy@126.com [The Fourth Affiliated Hospital of China Medical University, Shenyang 110032 (China); Sun, Dong-Xue [School of Traditional Chinese Medicine, Shenyang Pharmaceutical University, No. 103, Wenhua Road, Shenyang 110016 (China); Cao, Yun-Feng [The First Affiliated Hospital of Liaoning Medical University, Jinzhou 121001 (China); Joint Center for Translational Medicine, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road, Dalian 116023 (China); Ai, Chun-Zhi [Joint Center for Translational Medicine, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road, Dalian 116023 (China); Qu, Yan-Qing [Thyroid Surgery, Yantaishan Hospital, Yantai, Shandong (China); Hu, Cui-Min [Joint Center for Translational Medicine, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road, Dalian 116023 (China); Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC 20057 (United States); Jiang, Changtao [Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892 (United States); Dong, Pei-Pei [Academy of Integrative Medicine, Dalian Medical University, Dalian 116044 (China); Sun, Xiao-Yu; Hong, Mo [Joint Center for Translational Medicine, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road, Dalian 116023 (China); Tanaka, Naoki; Gonzalez, Frank J. [Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892 (United States); and others

2014-05-15

Herb–drug interaction strongly limits the clinical application of herbs and drugs, and the inhibition of herbal components towards important drug-metabolizing enzymes (DMEs) has been regarded as one of the most important reasons. The present study aims to investigate the inhibition potential of andrographolide derivatives towards one of the most important phase II DMEs UDP-glucuronosyltransferases (UGTs). Recombinant UGT isoforms (except UGT1A4)-catalyzed 4-methylumbelliferone (4-MU) glucuronidation reaction and UGT1A4-catalyzed trifluoperazine (TFP) glucuronidation were employed to firstly screen the andrographolide derivatives' inhibition potential. High specific inhibition of andrographolide derivatives towards UGT2B7 was observed. The inhibition type and parameters (K{sub i}) were determined for the compounds exhibiting strong inhibition capability towards UGT2B7, and human liver microsome (HLMs)-catalyzed zidovudine (AZT) glucuronidation probe reaction was used to furtherly confirm the inhibition behavior. In combination of inhibition parameters (K{sub i}) and in vivo concentration of andrographolide and dehydroandrographolide, the potential in vivo inhibition magnitude was predicted. Additionally, both the in vitro inhibition data and computational modeling results provide important information for the modification of andrographolide derivatives as selective inhibitors of UGT2B7. Taken together, data obtained from the present study indicated the potential herb–drug interaction between Andrographis paniculata and the drugs mainly undergoing UGT2B7-catalyzed metabolic elimination, and the andrographolide derivatives as potential candidates for the selective inhibitors of UGT2B7. - Highlights: • Specific inhibition of andrographolide derivatives towards UGT2B7. • Herb-drug interaction related withAndrographis paniculata. • Guidance for design of UGT2B7 specific inhibitors.

Reduction of bilirubin by targeting human heme oxygenase-1 through siRNA.

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Xia, Zhen-Wei; Li, Chun-E; Jin, You-Xin; Shi, Yi; Xu, Li-Qing; Zhong, Wen-Wei; Li, Yun-Zhu; Yu, Shan-Chang; Zhang, Zi-Li

2007-04-01

Neonatal hyperbilirubinemia is a common clinical condition caused mainly by the increased production and decreased excretion of bilirubin. Current treatment is aimed at reducing the serum levels of bilirubin. Heme oxygenase-1 (HO-1) is a rate-limiting enzyme that generates bilirubin. In this study we intended to suppress HO-1 using the RNA interference technique. Small interfering RNA (siRNA)-A, -B, and -C were designed based on human HO-1 (hHO-1) mRNA sequences. siRNA was transfected into a human hepatic cell line (HL-7702). hHO-1 transcription and protein levels were then determined. In addition, the inhibitory effect of siRNA on hHO-1 was assessed in cells treated with hemin or transfected with an hHO-1 plasmid. siRNA-C showed the most potent suppressive effect on hHO-1. This inhibition is dose and time dependent. Compared with control, both hemin and hHO-1 plasmids up-regulated hHO-1 expression in HL-7702 cells. However, the up-regulation was significantly attenuated by siRNA-C. Furthermore, the decrease in hHO-1 activity was coincident with the suppression of its transcription. Finally, siRNA-C was shown to reduce hHO-1 enzymatic activity and bilirubin levels. Thus, this study provides a novel therapeutic rationale by blocking bilirubin formation via siRNA for preventing and treating neonatal hyperbilirubinemia and bilirubin encephalopathy at an early clinical stage.

Modulation of bilirubin neurotoxicity by the Abcb1 transporter in the Ugt1-/- lethal mouse model of neonatal hyperbilirubinemia.

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Bockor, Luka; Bortolussi, Giulia; Vodret, Simone; Iaconcig, Alessandra; Jašprová, Jana; Zelenka, Jaroslav; Vitek, Libor; Tiribelli, Claudio; Muro, Andrés F

2017-01-01

Moderate neonatal jaundice is the most common clinical condition during newborn life. However, a combination of factors may result in acute hyperbilirubinemia, placing infants at risk of developing bilirubin encephalopathy and death by kernicterus. While most risk factors are known, the mechanisms acting to reduce susceptibility to bilirubin neurotoxicity remain unclear. The presence of modifier genes modulating the risk of developing bilirubin-induced brain damage is increasingly being recognised. The Abcb1 and Abcc1 members of the ABC family of transporters have been suggested to have an active role in exporting unconjugated bilirubin from the central nervous system into plasma. However, their role in reducing the risk of developing neurological damage and death during neonatal development is still unknown.To this end, we mated Abcb1a/b-/- and Abcc1-/- strains with Ugt1-/- mice, which develop severe neonatal hyperbilirubinemia. While about 60% of Ugt1-/- mice survived after temporary phototherapy, all Abcb1a/b-/-/Ugt1-/- mice died before postnatal day 21, showing higher cerebellar levels of unconjugated bilirubin. Interestingly, Abcc1 role appeared to be less important.In the cerebellum of Ugt1-/- mice, hyperbilirubinemia induced the expression of Car and Pxr nuclear receptors, known regulators of genes involved in the genotoxic response.We demonstrated a critical role of Abcb1 in protecting the cerebellum from bilirubin toxicity during neonatal development, the most clinically relevant phase for human babies, providing further understanding of the mechanisms regulating bilirubin neurotoxicity in vivo. Pharmacological treatments aimed to increase Abcb1 and Abcc1 expression, could represent a therapeutic option to reduce the risk of bilirubin neurotoxicity. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Combined effect of regulatory polymorphisms on transcription of UGT1A1 as a cause of Gilbert syndrome

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Sato Hiroshi

2010-06-01

Full Text Available Abstract Background Gilbert syndrome is caused by defects in bilirubin UDP-glucuronosyltransferase (UGT1A1. The most common variation believed to be involved is A(TA7TAA. Although several polymorphisms have been found to link with A(TA7TAA, the combined effect of regulatory polymorphisms in the development of Gilbert syndrome remains unclear. Methods In an analysis of 15 patients and 60 normal subjects, we detected 14 polymorphisms and nine haplotypes in the regulatory region. We classified the 4-kbp regulatory region of the patients into: the TATA box including A(TA7TAA; a phenobarbital responsive enhancer module including c.-3275T>G; and a region including other ten linked polymorphisms. The effect on transcription of these polymorphisms was studied. Results All haplotypes with A(TA7TAA had c.-3275T>G and additional polymorphisms. In an in-vitro expression study of the 4-kbp regulatory region, A(TA7TAA alone did not significantly reduce transcription. In contrast, c.-3275T>G reduced transcription to 69% of that of wild type, and the linked polymorphisms reduced transcription to 88% of wild type. Transcription of the typical regulatory region of the patients was 56% of wild type. Co-expression of constitutive androstane receptor (CAR increased the transcription of wild type by a factor of 4.3. Each polymorphism by itself did not reduce transcription to the level of the patients, however, even in the presence of CAR. Conclusions These results imply that co-operation of A(TA7TAA, c.-3275T>G and the linked polymorphisms is necessary in causing Gilbert syndrome.

Serum bilirubin levels are inversely associated with PAI-1 and fibrinogen in Korean subjects.

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Cho, Hyun Sun; Lee, Sung Won; Kim, Eun Sook; Shin, Juyoung; Moon, Sung Dae; Han, Je Ho; Cha, Bong Yun

2016-01-01

Oxidative stress may contribute to atherosclerosis and increased activation of the coagulation pathway. Bilirubin may reduce activation of the hemostatic system to inhibit oxidative stress, which would explain its cardioprotective properties shown in many epidemiological studies. This study investigated the association of serum bilirubin with fibrinogen and plasminogen activator inhibitor-1 (PAI-1), respectively. A cross-sectional analysis was performed on 968 subjects (mean age, 56.0 ± 11.2 years; 61.1% men) undergoing a general health checkup. Serum biochemistry was analyzed including bilirubin subtypes, insulin resistance (using homeostasis model of assessment [HOMA]), C-reactive protein (CRP), fibrinogen, and PAI-1. Compared with subjects with a total bilirubin (TB) concentration of 17.1 μmol/L had a smaller waist circumference, a lower triglyceride level, a lower prevalence of metabolic syndrome, and decreased HOMA-IR and CRP levels. Correlation analysis revealed linear relationships of fibrinogen with TB and direct bilirubin (DB), whereas PAI-1 was correlated with DB. After adjustment for confounding factors, bilirubin levels were inversely associated with fibrinogen and PAI-1 levels, respectively. Multivariate regression models showed a negative linear relationship between all types of bilirubin and fibrinogen, whereas there was a significant linear relationship between PAI-1 and DB. High bilirubin concentrations were independently associated with low levels of fibrinogen and PAI-1, respectively. The association between TB and PAI-1 was confined to the highest TB concentration category whereas DB showed a linear association with PAI-1. Bilirubin may protect against the development of atherothrombosis by reducing the hemostatic response. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Bilirubin Prevents Atherosclerotic Lesion Formation in Low-Density Lipoprotein Receptor-Deficient Mice by Inhibiting Endothelial VCAM-1 and ICAM-1 Signaling.

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Vogel, Megan E; Idelman, Gila; Konaniah, Eddy S; Zucker, Stephen D

2017-04-01

Numerous epidemiological studies support an inverse association between serum bilirubin levels and the incidence of cardiovascular disease; however, the mechanism(s) by which bilirubin may protect against atherosclerosis is undefined. The goals of the present investigations were to assess the ability of bilirubin to prevent atherosclerotic plaque formation in low-density lipoprotein receptor-deficient ( Ldlr -/- ) mice and elucidate the molecular processes underlying this effect. Bilirubin, at physiological concentrations (≤20 μmol/L), dose-dependently inhibits THP-1 monocyte migration across tumor necrosis factor α-activated human umbilical vein endothelial cell monolayers without altering leukocyte binding or cytokine production. A potent antioxidant, bilirubin effectively blocks the generation of cellular reactive oxygen species induced by the cross-linking of endothelial vascular cell adhesion molecule 1 (VCAM-1) or intercellular adhesion molecule 1 (ICAM-1). These findings were validated by treating cells with blocking antibodies or with specific inhibitors of VCAM-1 and ICAM-1 signaling. When administered to Ldlr -/- mice on a Western diet, bilirubin (30 mg/kg intraperitoneally) prevents atherosclerotic plaque formation, but does not alter circulating cholesterol or chemokine levels. Aortic roots from bilirubin-treated animals exhibit reduced lipid and collagen deposition, decreased infiltration of monocytes and lymphocytes, fewer smooth muscle cells, and diminished levels of chlorotyrosine and nitrotyrosine, without changes in VCAM-1 or ICAM-1 expression. Bilirubin suppresses atherosclerotic plaque formation in Ldlr -/- mice by disrupting endothelial VCAM-1- and ICAM-1-mediated leukocyte migration through the scavenging of reactive oxygen species signaling intermediaries. These findings suggest a potential mechanism for the apparent cardioprotective effects of bilirubin. © 2017 The Authors. Published on behalf of the American Heart Association, Inc

Molecular cloning and tissue-specific transcriptional regulation of the first peroxidase family member, Udp1, in stinging nettle (Urtica dioica).

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Douroupi, Triantafyllia G; Papassideri, Issidora S; Stravopodis, Dimitrios J; Margaritis, Lukas H

2005-12-05

A full-length cDNA clone, designated Udp1, was isolated from Urtica dioica (stinging nettle), using a polymerase chain reaction based strategy. The putative Udp1 protein is characterized by a cleavable N-terminal signal sequence, likely responsible for the rough endoplasmic reticulum entry and a 310 amino acids mature protein, containing all the important residues, which are evolutionary conserved among different members of the plant peroxidase family. A unique structural feature of the Udp1 peroxidase is defined into the short carboxyl-terminal extension, which could be associated with the vacuolar targeting process. Udp1 peroxidase is differentially regulated at the transcriptional level and is specifically expressed in the roots. Interestingly, wounding and ultraviolet radiation stress cause an ectopic induction of the Udp1 gene expression in the aerial parts of the plant. A genomic DNA fragment encoding the Udp1 peroxidase was also cloned and fully sequenced, revealing a structural organization of three exons and two introns. The phylogenetic relationships of the Udp1 protein to the Arabidopsis thaliana peroxidase family members were also examined and, in combination with the homology modelling approach, dictated the presence of distinct structural elements, which could be specifically involved in the determination of substrate recognition and subcellular localization of the Udp1 peroxidase.

Exome-Wide Association Study Identifies New Low-Frequency and Rare UGT1A1 Coding Variants and UGT1A6 Coding Variants Influencing Serum Bilirubin in Elderly Subjects

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Oussalah, Abderrahim; Bosco, Paolo; Anello, Guido; Spada, Rosario; Guéant-Rodriguez, Rosa-Maria; Chery, Céline; Rouyer, Pierre; Josse, Thomas; Romano, Antonino; Elia, Maurizzio; Bronowicki, Jean-Pierre; Guéant, Jean-Louis

2015-01-01

Abstract Genome-wide association studies (GWASs) have identified loci contributing to total serum bilirubin level. However, no exome-wide approaches have been performed to address this question. Using exome-wide approach, we assessed the influence of protein-coding variants on unconjugated, conjugated, and total serum bilirubin levels in a well-characterized cohort of 773 ambulatory elderly subjects from Italy. Coding variants were replicated in 227 elderly subjects from the same area. We identified 4 missense rare (minor allele frequency, MAF bilirubin level (P = 2.34 × 10−34, P = 7.02 × 10−34, and P = 8.27 × 10−34), as well as unconjugated, and conjugated bilirubin levels. We also identified UGT1A6 variants in association with total (rs6759892, p.Ser7Ala, P = 1.98 × 10−26; rs2070959, p.Thr181Ala, P = 2.87 × 10−27; and rs1105879, p.Arg184Ser, P = 3.27 × 10−29), unconjugated, and conjugated bilirubin levels. All UGT1A1 intronic variants (rs887829, rs6742078, and rs4148325) and UGT1A6 coding variants (rs6759892, rs2070959, and rs1105879) were significantly associated with gallstone-related cholecystectomy risk. The UGT1A6 variant rs2070959 (p.Thr181Ala) was associated with the highest risk of gallstone–related cholecystectomy (OR, 4.58; 95% CI, 1.58–13.28; P = 3.21 × 10−3). Using an exome-wide approach we identified coding variants on UGT1A1 and UGT1A6 genes in association with serum bilirubin level and hyperbilirubinemia risk in elderly subjects. UGT1A1 intronic single-nucleotide polymorphisms (SNPs) (rs6742078, rs887829, rs4148324) serve as proxy markers for the low-frequency and rare UGT1A1 variants, thereby providing mechanistic explanation to the relationship between UGT1A1 intronic SNPs and the UGT1A1 enzyme activity. UGT1A1 and UGT1A6 variants might be potentially associated with gallstone-related cholecystectomy risk. PMID:26039129

Relationship between serum bilirubin concentrations and diabetic nephropathy in Shanghai Han's patients with type 1 diabetes mellitus.

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Li, Xu; Zhang, Lei; Chen, Haibing; Guo, Kaifeng; Yu, Haoyong; Zhou, Jian; Li, Ming; Li, Qing; Li, Lianxi; Yin, Jun; Liu, Fang; Bao, Yuqian; Han, Junfeng; Jia, Weiping

2017-03-31

Recent studies highlight a negative association between total bilirubin concentrations and albuminuria in patients with type 2 diabetes mellitus. Our study evaluated the relationship between bilirubin concentrations and the prevalence of diabetic nephropathy (DN) in Chinese patients with type 1 diabetes mellitus (T1DM). A total of 258 patients with T1DM were recruited and bilirubin concentrations were compared between patients with or without diabetic nephropathy. Multiple stepwise regression analysis was used to examine the relationship between bilirubin concentrations and 24 h urinary microalbumin. Binary logistic regression analysis was performed to assess independent risk factors for diabetic nephropathy. Participants were divided into four groups according to the quartile of total bilirubin concentrations (Q1, 0.20-0.60; Q2, 0.60-0.80; Q3, 0.80-1.00; Q4, 1.00-1.90 mg/dL) and the chi-square test was used to compare the prevalence of DN in patients with T1DM. The median bilirubin level was 0.56 (interquartile: 0.43-0.68 mg/dL) in the DN group, significantly lower than in the non-DN group (0.70 [interquartile: 0.58-0.89 mg/dL], P 1). Spearman's correlational analysis showed bilirubin concentrations were inversely correlated with 24 h urinary microalbumin (r = -0.13, P 1.90% to 2.00%. High bilirubin concentrations are independently and negatively associated with albuminuria and the prevalence of DN in patients with T1DM.

Serum bilirubin concentration is associated with eGFR and urinary albumin excretion in patients with type 1 diabetes mellitus.

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Nishimura, Takeshi; Tanaka, Masami; Sekioka, Risa; Itoh, Hiroshi

2015-01-01

Although relationships of serum bilirubin concentration with estimated glomerular filtration rate (eGFR) and urinary albumin excretion (UAE) in patients with type 2 diabetes have been reported, whether such relationships exist in patients with type 1 diabetes is unknown. A total of 123 patients with type 1 diabetes were investigated in this cross-sectional study. The relationship between bilirubin (total and indirect) concentrations and log(UAE) as well as eGFR was examined by Pearson's correlation analyses. Multivariate regression analyses were used to assess the association of bilirubin (total and indirect) with eGFR as well as log(UAE). A positive correlation was found between serum bilirubin concentration and eGFR; total bilirubin (r=0.223, p=0.013), indirect bilirubin (r=0.244, p=0.007). A negative correlation was found between serum bilirubin concentration and log(UAE); total bilirubin (r=-0.258, p=0.005), indirect bilirubin (r=-0.271, p=0.003). Multivariate regression analyses showed that indirect bilirubin concentration was an independent determinant of eGFR and log(UAE). Bilirubin concentration is associated with both eGFR and log(UAE) in patients with type 1 diabetes. Bilirubin might have a protective role in the progression of type 1 diabetic nephropathy. Copyright © 2015 Elsevier Inc. All rights reserved.

Identification of heme oxygenase-1 stimulators by a convenient ELISA-based bilirubin quantification assay.

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Rücker, Hannelore; Amslinger, Sabine

2015-01-01

The upregulation of heme oxygenase-1 (HO-1) has proven to be a useful tool for fighting inflammation. In order to identify new HO-1 inducers, an efficient screening method was developed which can provide new lead structures for drug research. We designed a simple ELISA-based HO-1 enzyme activity assay, which allows for the screening of 12 compounds in parallel in the setting of a 96-well plate. The well-established murine macrophage cell line RAW264.7 is used and only about 26µg of protein from whole cell lysates is needed for the analysis of HO-1 activity. The quantification of HO-1 activity is based on an indirect ELISA using the specific anti-bilirubin antibody 24G7 to quantify directly bilirubin in the whole cell lysate, applying a horseradish peroxidase-tagged antibody together with ortho-phenylenediamine and H2O2 for detection. The bilirubin is produced on the action of HO enzymes by converting their substrate heme to biliverdin and additional recombinant biliverdin reductase together with NADPH at pH 7.4 in buffer. This sensitive assay allows for the detection of 0.57-82pmol bilirubin per sample in whole cell lysates. Twenty-three small molecules, mainly natural products with an α,β-unsaturated carbonyl unit such as polyphenols, including flavonoids and chalcones, terpenes, an isothiocyanate, and the drug oltipraz were tested at typically 6 or 24h incubation with RAW264.7 cells. The activity of known HO-1 inducers was confirmed, while the chalcones cardamonin, flavokawain A, calythropsin, 2',3,4'-trihydroxy-4-methoxychalcone (THMC), and 2',4'-dihydroxy-3,4-dimethoxychalcone (DHDMC) were identified as new potent HO-1 inducers. The highest inductive power after 6h incubation was found at 10µM for DHDMC (6.1-fold), carnosol (3.9-fold), butein (3.1-fold), THMC (2.9-fold), and zerumbone (2.5-fold). Moreover, the time dependence of HO-1 protein production for DHDMC was compared to its enzyme activity, which was further evaluated in the presence of

Phenobarbital induction and chemical synergism demonstrate the role of UDP-glucuronosyltransferases in detoxification of naphthalophos by Haemonchus contortus larvae.

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Kotze, Andrew C; Ruffell, Angela P; Ingham, Aaron B

2014-12-01

We used an enzyme induction approach to study the role of detoxification enzymes in the interaction of the anthelmintic compound naphthalophos with Haemonchus contortus larvae. Larvae were treated with the barbiturate phenobarbital, which is known to induce the activity of a number of detoxification enzymes in mammals and insects, including cytochromes P450 (CYPs), UDP-glucuronosyltransferases (UDPGTs), and glutathione (GSH) S-transferases (GSTs). Cotreatment of larvae with phenobarbital and naphthalophos resulted in a significant increase in the naphthalophos 50% inhibitory concentration (IC50) compared to treatment of larvae with the anthelmintic alone (up to a 28-fold increase). The phenobarbital-induced drug tolerance was reversed by cotreatment with the UDPGT inhibitors 5-nitrouracil, 4,6-dihydroxy-5-nitropyrimidine, probenecid, and sulfinpyrazone. Isobologram analysis of the interaction of 5-nitrouracil with naphthalophos in phenobarbital-treated larvae clearly showed the presence of strong synergism. The UDPGT inhibitors 5-nitrouracil, 4,6-dihydroxy-5-nitropyrimidine, and probenecid also showed synergistic effects with non-phenobarbital-treated worms (synergism ratio up to 3.2-fold). This study indicates that H. contortus larvae possess one or more UDPGT enzymes able to detoxify naphthalophos. In highlighting the protective role of this enzyme group, this study reveals the potential for UDPGT enzymes to act as a resistance mechanism that may develop under drug selection pressure in field isolates of this species. In addition, the data indicate the potential for a chemotherapeutic approach utilizing inhibitors of UDPGT enzymes as synergists to increase the activity of naphthalophos against parasitic worms and to combat detoxification-mediated drug resistance if it arises in the field. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Sulfation of fulvestrant by human liver cytosols and recombinant SULT1A1 and SULT1E1

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Edavana VK

2011-11-01

Full Text Available Vineetha Koroth Edavana1, Xinfeng Yu1, Ishwori B Dhakal1, Suzanne Williams1, Baitang Ning2, Ian T Cook3, David Caldwell1, Charles N Falany3, Susan Kadlubar11Division of Medical Genetics, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA; 2Division of Personalized Nutrition and Medicine, National Center for Toxicological Research, Food and Drug Administration, Jefferson, AR, USA; 3Department of Pharmacology, University of Alabama, Birmingham, AL, USAAbstract: Fulvestrant (Faslodex™ is a pure antiestrogen that is approved to treat hormone receptor-positive metastatic breast cancer in postmenopausal women. Previous studies have demonstrated that fulvestrant metabolism in humans involves cytochromes P450 and UDP-glucuronosyltransferases (UGTs. To date, fulvestrant sulfation has not been characterized. This study examined fulvestrant sulfation with nine recombinant sulfotransferases and found that only SULT1A1 and SULT1E1 displayed catalytic activity toward this substrate, with Km of 4.2 ± 0.99 and 0.2 ± 0.16 µM, respectively. In vitro assays of 104 human liver cytosols revealed marked individual variability that was highly correlated with β-naphthol sulfation (SULT1A1 diagnostic substrate; r = 0.98, P < 0.0001, but not with 17ß-estradiol sulfation (SULT1E1 diagnostic substrate; r = 0.16, P = 0.10. Fulvestrant sulfation was correlated with both SULT1A1*1/2 genotype (P value = 0.023 and copy number (P < 0.0001. These studies suggest that factors influencing SULT1A1/1E1 tissue expression and/or enzymatic activity could influence the efficacy of fulvestrant therapy.Keywords: fulvestrant, sulfotransferase, genotype, copy number

Synthesis and Evaluation of Bicyclo[3.1.0]hexane-Based UDP-Galf Analogues as Inhibitors of the Mycobacterial Galactofuranosyltransferase GlfT2

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Todd L. Lowary

2016-08-01

Full Text Available UDP-galactofuranose (UDP-Galf is the donor substrate for both bifunctional galactofuranosyltransferases, GlfT1 and GlfT2, which are involved in the biosynthesis of mycobacterial galactan. In this paper, a group of UDP-Galf mimics were synthesized via reductive amination of a bicyclo[3.1.0]hexane-based amine by reacting with aromatic, linear, or uridine-containing aldehydes. These compounds were evaluated against GlfT2 using a coupled spectrophotometric assay, and were shown to be weak inhibitors of the enzyme.

Coupling of UDP-glucuronosyltransferases and multidrug resistance-associated proteins is responsible for the intestinal disposition and poor bioavailability of emodin

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Liu, Wei; Feng, Qian; Li, Ye; Ye, Ling; Hu, Ming; Liu, Zhongqiu

2012-01-01

Emodin is a poorly bioavailable but promising plant-derived anticancer drug candidate. The low oral bioavailability of emodin is due to its extensive glucuronidation in the intestine and liver. Caco-2 cell culture model was used to investigate the interplay between UDP-glucuronosyltransferases (UGTs) and efflux transporters in the intestinal disposition of emodin. Bidirectional transport assays of emodin at different concentrations were performed in the Caco-2 monolayers with or without multidrug resistance-associated protein (MRP) and breast cancer resistance protein (BCRP) efflux transporter chemical inhibitors. The bidirectional permeability of emodin and its glucuronide in the Caco-2 monolayers was determined. Emodin was rapidly metabolized to emodin glucuronide in Caco-2 cells. LTC4, a potent inhibitor of MRP2, decreased the efflux of emodin glucuronide and also substantially increased the intracellular glucuronide level in the basolateral-to-apical (B–A) direction. MK-571, chemical inhibitor of MRP2, MRP3, and MRP4, significantly reduced the efflux of glucuronide in the apical-to-basolateral (A–B) and B–A directions in a dose-dependent manner. However, dipyridamole, a BCRP chemical inhibitor demonstrated no effect on formation and efflux of emodin glucuronide in Caco-2 cells. In conclusion, UGT is a main metabolic pathway for emodin in the intestine, and the MRP family is composed of major efflux transporters responsible for the excretion of emodin glucuronide in the intestine. The coupling of UGTs and MRP efflux transporters causes the extensive metabolism, excretion, and low bioavailability of emodin. -- Highlights: ► Glucuronidation is the main reason for the poor oral bioavailability of emodin. ► Efflux transporters are involved in the excretion of emodin glucuronide. ► The intestine is the main organ for metabolism of emodin.

Coupling of UDP-glucuronosyltransferases and multidrug resistance-associated proteins is responsible for the intestinal disposition and poor bioavailability of emodin

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Liu, Wei; Feng, Qian; Li, Ye; Ye, Ling [Department of Pharmaceutics, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, Guangdong (China); Hu, Ming, E-mail: mhu@uh.edu [Department of Pharmaceutics, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, Guangdong (China); Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, 1441 Moursund Street, Houston, TX 77030 (United States); Liu, Zhongqiu, E-mail: liuzq@smu.edu.cn [Department of Pharmaceutics, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, Guangdong (China)

2012-12-15

Emodin is a poorly bioavailable but promising plant-derived anticancer drug candidate. The low oral bioavailability of emodin is due to its extensive glucuronidation in the intestine and liver. Caco-2 cell culture model was used to investigate the interplay between UDP-glucuronosyltransferases (UGTs) and efflux transporters in the intestinal disposition of emodin. Bidirectional transport assays of emodin at different concentrations were performed in the Caco-2 monolayers with or without multidrug resistance-associated protein (MRP) and breast cancer resistance protein (BCRP) efflux transporter chemical inhibitors. The bidirectional permeability of emodin and its glucuronide in the Caco-2 monolayers was determined. Emodin was rapidly metabolized to emodin glucuronide in Caco-2 cells. LTC4, a potent inhibitor of MRP2, decreased the efflux of emodin glucuronide and also substantially increased the intracellular glucuronide level in the basolateral-to-apical (B–A) direction. MK-571, chemical inhibitor of MRP2, MRP3, and MRP4, significantly reduced the efflux of glucuronide in the apical-to-basolateral (A–B) and B–A directions in a dose-dependent manner. However, dipyridamole, a BCRP chemical inhibitor demonstrated no effect on formation and efflux of emodin glucuronide in Caco-2 cells. In conclusion, UGT is a main metabolic pathway for emodin in the intestine, and the MRP family is composed of major efflux transporters responsible for the excretion of emodin glucuronide in the intestine. The coupling of UGTs and MRP efflux transporters causes the extensive metabolism, excretion, and low bioavailability of emodin. -- Highlights: ► Glucuronidation is the main reason for the poor oral bioavailability of emodin. ► Efflux transporters are involved in the excretion of emodin glucuronide. ► The intestine is the main organ for metabolism of emodin.

A translationally optimized AAV-UGT1A1 vector drives safe and long-lasting correction of Crigler-Najjar syndrome

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Giuseppe Ronzitti

2016-01-01

Full Text Available Crigler-Najjar syndrome is a severe metabolic disease of the liver due to a reduced activity of the UDP Glucuronosyltransferase 1A1 (UGT1A1 enzyme. In an effort to translate to the clinic an adeno-associated virus vector mediated liver gene transfer approach to treat Crigler-Najjar syndrome, we developed and optimized a vector expressing the UGT1A1 transgene. For this purpose, we designed and tested in vitro and in vivo multiple codon-optimized UGT1A1 transgene cDNAs. We also optimized noncoding sequences in the transgene expression cassette. Our results indicate that transgene codon-optimization is a strategy that can improve efficacy of gene transfer but needs to be carefully tested in vitro and in vivo. Additionally, while inclusion of introns can enhance gene expression, optimization of these introns, and in particular removal of cryptic ATGs and splice sites, is an important maneuver to enhance safety and efficacy of gene transfer. Finally, using a translationally optimized adeno-associated virus vector expressing the UGT1A1 transgene, we demonstrated rescue of the phenotype of Crigler-Najjar syndrome in two animal models of the disease, Gunn rats and Ugt1a1-/- mice. We also showed long-term (>1 year correction of the disease in Gunn rats. These results support further translation of the approach to humans.

The influence of charge and the distribution of charge in the polar region of phospholipids on the activity of UDP-glucuronosyltransferase.

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Zakim, D; Eibl, H

1992-07-05

Studies of the mechanism of lipid-induced regulation of the microsomal enzyme UDP-glucuronosyltransferase have been extended by examining the influence of charge within the polar region on the ability of lipids to activate delipidated pure enzyme. The effects of net negative charge, of charge separation in phosphocholine, and of the distribution of charge in the polar region of lipids were studied using the GT2p isoform isolated from pig liver. Prior experiments have shown that lipids with net negative charge inhibit the enzyme (Zakim, D., Cantor, M., and Eibl, H. (1988) J. Biol. Chem. 263, 5164-5169). The current experiments show that the extent of inhibition on a molar basis increases as the net negative charge increases from -1 to -2. The inhibitory effect of negatively charged lipids is on the functional state of the enzyme and is not due to electrostatic repulsion of negatively charged substrates of the enzyme. Although the inhibitory effect of net negative charge is removed when negative charge is balanced by a positive charge due to a quaternary nitrogen, neutrality of the polar region is not a sufficient condition for activation of the enzyme. In addition to a balance of charge between Pi and the quaternary nitrogen, the distance between the negative and positive charges and the orientation of the dipole created by them are critical for activation of GT2p. The negative and positive charges must be separated by the equivalent of three -CH2- groups for optimal activation by a lipid. Shortening this distance by one -CH2- unit leads to a lipid that is ineffective in activating the enzyme. Reversal of the orientation of the dipole in which the negative charge is on the polymethylene side of the lipid-water interface and the positive charge extends into water also produces a lipid that is not effective for activating GT2p. On the other hand, lipids with phosphoserine as the polar region, which has the "normal" P-N distance but carries a net negative charge, do

Role of UDP-Glucuronosyltransferase 1A1 in the Metabolism and Pharmacokinetics of Silymarin Flavonolignans in Patients with HCV and NAFLD

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Ying Xie

2017-01-01

Full Text Available Silymarin is the most commonly used herbal medicine by patients with chronic liver disease. Silymarin flavonolignans undergo rapid first-pass metabolism primarily by glucuronidation. The aims of this investigation were: (1 to determine the association of UGT1A1*28 polymorphism with the area under the plasma concentration-time curves (AUCs for silybin A (SA and silybin B (SB; (2 to evaluate the effect of UGT1A1*28 polymorphism on the profile of flavonolignan glucuronide conjugates found in the plasma; and (3 to investigate the role of UGT1A1 enzyme kinetics on the pharmacokinetics of SA and SB. AUCs and metabolic ratios for thirty-three patients with chronic liver disease administered oral doses of silymarin were compared between different UGT1A1*28 genotypes. The AUCs, metabolic ratios, and the profiles of major SA and SB glucuronides did not differ significantly among the three UGT1A1 genotypes. In contrast, an increase in the proportion of sulfated flavonolignan conjugates in plasma was observed in subjects with UGT1A1*28/*28 genotype compared to subjects carrying wild type alleles. Differences in SA and SB in vitro intrinsic clearance estimates for UGTIA1 correlated inversely with SA and SB exposures observed in vivo indicating a major role for UGT1A1 in silymarin metabolism. In addition, a significant difference in the metabolic ratio observed between patients with NAFLD and HCV suggests that any effect of UGT1A1 polymorphism may be obscured by a greater effect of liver disease on the pharmacokinetics of silymarin. Taken together, these results suggest the presence of the UGT1A1*28 allele does not contribute significantly to a large inter-subject variability in the pharmacokinetics of silybin A and silybin B which may obscure the ability to detect beneficial effects of silymarin in patients with liver disease.

Newborn Bilirubin Screening for Preventing Severe Hyperbilirubinemia and Bilirubin Encephalopathy: A Rapid Review.

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Bhardwaj, Kalpana; Locke, Tiffany; Biringer, Anne; Booth, Allyson; Darling, Elizabeth K; Dougan, Shelley; Harrison, Jane; Hill, Stephen; Johnson, Ana; Makin, Susan; Potter, Beth; Lacaze-Masmonteil, Thierry; Little, Julian

2017-01-01

According to the 2004 American Academy of Pediatrics guideline on the management of hyperbilirubinemia, every newborn should be assessed for the risk of developing severe hyperbilirubinemia with the help of predischarge total serum bilirubin or transcutaneous bilirubin measurements and/or assessments of clinical risk factors. The aim of this rapid review is 1) to review the evidence for 1) predicting and preventing severe hyperbilirubinemia and bilirubin encephalopathy, 2) determining the efficacy of home/community treatments (home phototherapy) in the prevention of severe hyperbilirubinemia, and 3) non-invasive/transcutaneous methods for estimating serum bilirubin level. In this rapid review, studies were identified through the Medline database. The main outcomes of interest were severe hyperbilirubinemia and encephalopathy. A subset of articles was double screened and all articles were critically appraised using the SIGN and AMSTAR checklists. This review investigated if systems approach is likely to reduce the occurrence of severe hyperbilirubinemia. Fifty-two studies met the inclusion criteria. Included studies assessed the association between bilirubin measurement early in neonatal life and the subsequent development of severe hyperbilirubinemia and chronic bilirubin encephalopathy/kernicterus. It was observed that, highest priority should be given to (i) universal bilirubin screening programs; (ii) implementation of community and midwife practice; (iii) outreach to communities for education of prospective parents; and (iv) development of clinical pathways to monitor, evaluate and track infants with severe hyperbilirubinemia. We found substantial observational evidence that severe hyperbilirubinemia can be accurately predicted and prevented through universal bilirubin screening. So far, there is no evidence of any harm. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Characterization of UDP-glucuronosyltransferase genes and their possible roles in multi-insecticide resistance in Plutella xylostella (L.).

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Li, Xiuxia; Shi, Haiyan; Gao, Xiwu; Liang, Pei

2018-03-01

Uridine diphosphate-glucuronosyltransferases (UGTs), as multifunctional detoxification enzymes, play important roles in the biotransformation of various compounds. However, their roles in insecticide resistance are still unclear. This study presents a genome-wide identification of the UGTs in diamondback moth, Plutella xylostella (L.), a notorious insect pest of cruciferous crops worldwide. The possible roles of these UGTs in insecticide resistance were evaluated. A total of 21 putative UGTs in P. xylostella were identified. Quantitative real-time polymerase chain reaction (PCR)-based analyses showed that all the UGT genes were expressed in all tested developmental stages and tissues. Bioassay results indicated that a field-collected population (BL) was resistant to 9 of 10 commonly used insecticides, and 10 of 21 UGT mRNAs were upregulated in the BL population. Exposure to the LC 50 of each insecticide affected the expression of most UGT genes. Among these, the expression levels of UGT40V1, UGT45B1 and UGT33AA4 were induced by more than five insecticides, whereas indoxacarb and metaflumizone significantly repressed the expression of most UGT genes. UGTs may play important roles in the metabolism of commonly used insecticides in P. xylostella. These findings provide valuable information for further research on the physiological and toxicological functions of specific UGT genes in P. xylostella. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Regulation of UGT1A1 and HNF1 transcription factor gene expression by DNA methylation in colon cancer cells

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Harvey Mario

2010-01-01

Full Text Available Abstract Background UDP-glucuronosyltransferase 1A1 (UGT1A1 is a pivotal enzyme involved in metabolism of SN-38, the active metabolite of irinotecan commonly used to treat metastatic colorectal cancer. We previously demonstrated aberrant methylation of specific CpG dinucleotides in UGT1A1-negative cells, and revealed that methylation state of the UGT1A1 5'-flanking sequence is negatively correlated with gene transcription. Interestingly, one of these CpG dinucleotides (CpG -4 is found close to a HNF1 response element (HRE, known to be involved in activation of UGT1A1 gene expression, and within an upstream stimulating factor (USF binding site. Results Gel retardation assays revealed that methylation of CpG-4 directly affect the interaction of USF1/2 with its cognate sequence without altering the binding for HNF1-alpha. Luciferase assays sustained a role for USF1/2 and HNF1-alpha in UGT1A1 regulation in colon cancer cells. Based on the differential expression profiles of HNF1A gene in colon cell lines, we also assessed whether methylation affects its expression. In agreement with the presence of CpG islands in the HNF1A promoter, treatments of UGT1A1-negative HCT116 colon cancer cells with a DNA methyltransferase inhibitor restore HNF1A gene expression, as observed for UGT1A1. Conclusions This study reveals that basal UGT1A1 expression in colon cells is positively regulated by HNF1-alpha and USF, and negatively regulated by DNA methylation. Besides, DNA methylation of HNF1A could also play an important role in regulating additional cellular drug metabolism and transporter pathways. This process may contribute to determine local inactivation of drugs such as the anticancer agent SN-38 by glucuronidation and define tumoral response.

Impairment of enzymatic antioxidant defenses is associated with bilirubin-induced neuronal cell death in the cerebellum of Ugt1 KO mice

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Bortolussi, G; Codarin, E; Antoniali, G; Vascotto, C; Vodret, S; Arena, S; Cesaratto, L; Scaloni, A; Tell, G; Muro, A F

2015-01-01

Severe hyperbilirubinemia is toxic during central nervous system development. Prolonged and uncontrolled high levels of unconjugated bilirubin lead to bilirubin-induced encephalopathy and eventually death by kernicterus. Despite extensive studies, the molecular and cellular mechanisms of bilirubin toxicity are still poorly defined. To fill this gap, we investigated the molecular processes underlying neuronal injury in a mouse model of severe neonatal jaundice, which develops hyperbilirubinemia as a consequence of a null mutation in the Ugt1 gene. These mutant mice show cerebellar abnormalities and hypoplasia, neuronal cell death and die shortly after birth because of bilirubin neurotoxicity. To identify protein changes associated with bilirubin-induced cell death, we performed proteomic analysis of cerebella from Ugt1 mutant and wild-type mice. Proteomic data pointed-out to oxidoreductase activities or antioxidant processes as important intracellular mechanisms altered during bilirubin-induced neurotoxicity. In particular, they revealed that down-representation of DJ-1, superoxide dismutase, peroxiredoxins 2 and 6 was associated with hyperbilirubinemia in the cerebellum of mutant mice. Interestingly, the reduction in protein levels seems to result from post-translational mechanisms because we did not detect significant quantitative differences in the corresponding mRNAs. We also observed an increase in neuro-specific enolase 2 both in the cerebellum and in the serum of mutant mice, supporting its potential use as a biomarker of bilirubin-induced neurological damage. In conclusion, our data show that different protective mechanisms fail to contrast oxidative burst in bilirubin-affected brain regions, ultimately leading to neurodegeneration. PMID:25950469

Olfactory Receptors in Non-Chemosensory Organs: The Nervous System in Health and Disease

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Ferrer, Isidro; Garcia-Esparcia, Paula; Carmona, Margarita; Carro, Eva; Aronica, Eleonora; Kovacs, Gabor G.; Grison, Alice; Gustincich, Stefano

2016-01-01

Olfactory receptors (ORs) and down-stream functional signaling molecules adenylyl cyclase 3 (AC3), olfactory G protein α subunit (Gαolf), OR transporters receptor transporter proteins 1 and 2 (RTP1 and RTP2), receptor expression enhancing protein 1 (REEP1), and UDP-glucuronosyltransferases (UGTs)

UDP-galactose 4'-epimerase activities toward UDP-Gal and UDP-GalNAc play different roles in the development of Drosophila melanogaster.

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Jennifer M I Daenzer

Full Text Available In both humans and Drosophila melanogaster, UDP-galactose 4'-epimerase (GALE catalyzes two distinct reactions, interconverting UDP-galactose (UDP-gal and UDP-glucose (UDP-glc in the final step of the Leloir pathway of galactose metabolism, and also interconverting UDP-N-acetylgalactosamine (UDP-galNAc and UDP-N-acetylglucosamine (UDP-glcNAc. All four of these UDP-sugars serve as vital substrates for glycosylation in metazoans. Partial loss of GALE in humans results in the spectrum disorder epimerase deficiency galactosemia; partial loss of GALE in Drosophila melanogaster also results in galactose-sensitivity, and complete loss in Drosophila is embryonic lethal. However, whether these outcomes in both humans and flies result from loss of one GALE activity, the other, or both has remained unknown. To address this question, we uncoupled the two activities in a Drosophila model, effectively replacing the endogenous dGALE with prokaryotic transgenes, one of which (Escherichia coli GALE efficiently interconverts only UDP-gal/UDP-glc, and the other of which (Plesiomonas shigelloides wbgU efficiently interconverts only UDP-galNAc/UDP-glcNAc. Our results demonstrate that both UDP-gal and UDP-galNAc activities of dGALE are required for Drosophila survival, although distinct roles for each activity can be seen in specific windows of developmental time or in response to a galactose challenge. By extension, these data also suggest that both activities might play distinct and essential roles in humans.

Prediction of Neonatal Hyperbilirubinemia Using 1st Day Serum Bilirubin Levels.

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Spoorthi, S M; Dandinavar, Siddappa F; Ratageri, Vinod H; Wari, Prakash K

2018-02-15

The study was conducted on Full term neonates with birth weight > 2.5 kg born in KIMS, Hubballi with an objective to determine the first day Total Serum Bilirubin (TSB) value so as to predict subsequent development of significant hyperbilirubinemia in term neonates. All enrolled neonates were sampled for TSB and blood group on Day 1 at 20 ± 4 h and then followed up clinically by Kramer's rule and when the clinical jaundice by Kramer's rule was >10 mg/dl, TSB levels were repeated. A total of 180 newborns were enrolled for the study and 165 babies completed the study. Out of these, 17(10.3%) babies had significant hyperbilirubinemia by day 5 of life. Using Receiver Operating Characteristic (ROC) Curve, a cut off TSB value of 6.15 mg/dl was determined with sensitivity of 82.4%, specificity of 81.8%, positive predictive value of 32.8%, negative predictive value 97.6%. In term neonates, the first day total bilirubin level at 20 ± 4 h of life <6.15 predicts the low risk of subsequent significant hyperbilirubinemia with high probability.

Inherited Disorders of Bilirubin Clearance

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Memon, Naureen; Weinberger, Barry I; Hegyi, Thomas; Aleksunes, Lauren M

2016-01-01

Inherited disorders of hyperbilirubinemia may be caused by increased bilirubin production or decreased bilirubin clearance. Reduced hepatic bilirubin clearance can be due to defective 1) unconjugated bilirubin uptake and intrahepatic storage, 2) conjugation of glucuronic acid to bilirubin (e.g. Gilbert syndrome, Crigler-Najjar syndrome, Lucey-Driscoll syndrome, breast milk jaundice), 3) bilirubin excretion into bile (Dubin-Johnson syndrome), or 4) conjugated bilirubin re-uptake (Rotor syndrome). In this review, the molecular mechanisms and clinical manifestations of these conditions are described, as well as current approaches to diagnosis and therapy. PMID:26595536

The triplet excited state of bilirubin

International Nuclear Information System (INIS)

Land, E.J.

1976-01-01

Pulse radiolysis of benzene solutions of 40 μM bilirubin alone or with 0.1 M biphenyl has yielded evidence for the formation of the triplet excited state of bilirubin. Measurements were made of a number of properties, including the absorption spectrum (lambdasub(max)500nm), lifetime 9μs), extinction coefficient (8800 M -1 cm -1 ), energy level (approximately 150 kJ mol -1 ) and the rate of quenching by oxygen (rate constant, 8.2 x 10 8 M -1 s -1 ). An upper limit of 0.1 has also been obtained for the singlet to triplet crossover efficiency of bilirubin following excitation by 353 nm radiation. Consideration is given to the relevance of these data to the mechanism of bilirubin photo-destruction, both in vivo and in vitro. (U.K.)

Modulation of Mrp1 (ABCc1 and Pgp (ABCb1 by bilirubin at the blood-CSF and blood-brain barriers in the Gunn rat.

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Silvia Gazzin

2011-01-01

Full Text Available Accumulation of unconjugated bilirubin (UCB in the brain causes bilirubin encephalopathy. Pgp (ABCb1 and Mrp1 (ABCc1, highly expressed in the blood-brain barrier (BBB and blood-cerebrospinal fluid barrier (BCSFB respectively, may modulate the accumulation of UCB in brain. We examined the effect of prolonged exposure to elevated concentrations of UCB on expression of the two transporters in homozygous, jaundiced (jj Gunn rats compared to heterozygous, not jaundiced (Jj littermates at different developmental stages (2, 9, 17 and 60 days after birth. BBB Pgp protein expression was low in both jj and Jj pups at 9 days (about 16-27% of adult values, despite the up-regulation in jj animals (2 and 1.3 fold higher than age matched Jj animals at P9 and P17-P60, respectively; Mrp1 protein expression was barely detectable. Conversely, at the BCSFB Mrp1 protein expression was rather high (60-70% of the adult values in both jj and Jj at P2, but was markedly (50% down-regulated in jj pups starting at P9, particularly in the 4(th ventricle choroid plexuses: Pgp was almost undetectable. The Mrp1 protein down regulation was accompanied by a modest up-regulation of mRNA, suggesting a translational rather than a transcriptional inhibition. In vitro exposure of choroid plexus epithelial cells obtained from normal rats to UCB, also resulted in a down-regulation of Mrp1 protein. These data suggest that down-regulation of Mrp1 protein at the BSCFB, resulting from a direct effect of UCB on epithelial cells, may impact the Mrp1-mediated neuroprotective functions of the blood-cerebrospinal fluid barrier and actually potentiate UCB neurotoxicity.

Substrate Specificity and Inhibitor Sensitivity of Plant UDP-Sugar Producing Pyrophosphorylases

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Daniel Decker

2017-09-01

Full Text Available UDP-sugars are essential precursors for glycosylation reactions producing cell wall polysaccharides, sucrose, glycoproteins, glycolipids, etc. Primary mechanisms of UDP sugar formation involve the action of at least three distinct pyrophosphorylases using UTP and sugar-1-P as substrates. Here, substrate specificities of barley and Arabidopsis (two isozymes UDP-glucose pyrophosphorylases (UGPase, Arabidopsis UDP-sugar pyrophosphorylase (USPase and Arabidopsis UDP-N-acetyl glucosamine pyrophosphorylase2 (UAGPase2 were investigated using a range of sugar-1-phosphates and nucleoside-triphosphates as substrates. Whereas all the enzymes preferentially used UTP as nucleotide donor, they differed in their specificity for sugar-1-P. UGPases had high activity with D-Glc-1-P, but could also react with Fru-1-P and Fru-2-P (Km values over 10 mM. Contrary to an earlier report, their activity with Gal-1-P was extremely low. USPase reacted with a range of sugar-1-phosphates, including D-Glc-1-P, D-Gal-1-P, D-GalA-1-P (Km of 1.3 mM, β-L-Ara-1-P and α-D-Fuc-1-P (Km of 3.4 mM, but not β-L-Fuc-1-P. In contrast, UAGPase2 reacted only with D-GlcNAc-1-P, D-GalNAc-1-P (Km of 1 mM and, to some extent, D-Glc-1-P (Km of 3.2 mM. Generally, different conformations/substituents at C2, C4, and C5 of the pyranose ring of a sugar were crucial determinants of substrate specificity of a given pyrophosphorylase. Homology models of UDP-sugar binding to UGPase, USPase and UAGPase2 revealed more common amino acids for UDP binding than for sugar binding, reflecting differences in substrate specificity of these proteins. UAGPase2 was inhibited by a salicylate derivative that was earlier shown to affect UGPase and USPase activities, consistent with a common structural architecture of the three pyrophosphorylases. The results are discussed with respect to the role of the pyrophosphorylases in sugar activation for glycosylated end-products.

Biliverdin reductase/bilirubin mediates the anti-apoptotic effect of hypoxia in pulmonary arterial smooth muscle cells through ERK1/2 pathway

International Nuclear Information System (INIS)

Song, Shasha; Wang, Shuang; Ma, Jun; Yao, Lan; Xing, Hao; Zhang, Lei; Liao, Lin; Zhu, Daling

2013-01-01

Inhibition of pulmonary arterial smooth muscle cell (PASMC) apoptosis induced by hypoxia plays an important role in pulmonary arterial remodeling leading to aggravate hypoxic pulmonary arterial hypertension. However, the mechanisms of hypoxia acting on PASMC apoptosis remain exclusive. Biliverdin reductase (BVR) has many essential biologic roles in physiological and pathological processes. Nevertheless, it is unclear whether the hypoxia-induced inhibition on PASMC apoptosis is mediated by BVR. In the present work, we found BVR majorly localized in PASMCs and was up-regulated in levels of protein and mRNA by hypoxia. Then we studied the contribution of BVR to anti-apoptotic response of hypoxia in PASMCs. Our results showed that siBVR, blocking generation of bilirubin, reversed the effect of hypoxia on enhancing cell survival and apoptotic protein (Bcl-2, procasepase-9, procasepase-3) expression, preventing nuclear shrinkage, DNA fragmentation and mitochondrial depolarization in starved PASMCs, which were recovered by exogenous bilirubin. Moreover, the inhibitory effect of bilirubin on PASMC apoptosis under hypoxic condition was blocked by the inhibitor of ERK1/2 pathway. Taken together, our data indicate that BVR contributes to the inhibitory process of hypoxia on PASMC apoptosis, which is mediated by bilirubin through ERK1/2 pathway. Highlights: • BVR expresses in PASMC and is up-regulated by hypoxia in protein and mRNA levels. • BVR/bilirubin contribute to the inhibitive process of hypoxia on PASMC apoptosis. • Bilirubin protects PASMC from apoptosis under hypoxia via ERK1/2 pathway

Biliverdin reductase/bilirubin mediates the anti-apoptotic effect of hypoxia in pulmonary arterial smooth muscle cells through ERK1/2 pathway

Energy Technology Data Exchange (ETDEWEB)

Song, Shasha [Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical, University (Daqing), Daqing 163319 (China); Wang, Shuang [Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical, University (Daqing), Daqing 163319 (China); Biopharmaceutical Key Laboratory of Heilongjiang Province, Harbin 150081 (China); Ma, Jun; Yao, Lan; Xing, Hao; Zhang, Lei; Liao, Lin [Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical, University (Daqing), Daqing 163319 (China); Zhu, Daling, E-mail: dalingz@yahoo.com [Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical, University (Daqing), Daqing 163319 (China); Biopharmaceutical Key Laboratory of Heilongjiang Province, Harbin 150081 (China)

2013-08-01

Inhibition of pulmonary arterial smooth muscle cell (PASMC) apoptosis induced by hypoxia plays an important role in pulmonary arterial remodeling leading to aggravate hypoxic pulmonary arterial hypertension. However, the mechanisms of hypoxia acting on PASMC apoptosis remain exclusive. Biliverdin reductase (BVR) has many essential biologic roles in physiological and pathological processes. Nevertheless, it is unclear whether the hypoxia-induced inhibition on PASMC apoptosis is mediated by BVR. In the present work, we found BVR majorly localized in PASMCs and was up-regulated in levels of protein and mRNA by hypoxia. Then we studied the contribution of BVR to anti-apoptotic response of hypoxia in PASMCs. Our results showed that siBVR, blocking generation of bilirubin, reversed the effect of hypoxia on enhancing cell survival and apoptotic protein (Bcl-2, procasepase-9, procasepase-3) expression, preventing nuclear shrinkage, DNA fragmentation and mitochondrial depolarization in starved PASMCs, which were recovered by exogenous bilirubin. Moreover, the inhibitory effect of bilirubin on PASMC apoptosis under hypoxic condition was blocked by the inhibitor of ERK1/2 pathway. Taken together, our data indicate that BVR contributes to the inhibitory process of hypoxia on PASMC apoptosis, which is mediated by bilirubin through ERK1/2 pathway. Highlights: • BVR expresses in PASMC and is up-regulated by hypoxia in protein and mRNA levels. • BVR/bilirubin contribute to the inhibitive process of hypoxia on PASMC apoptosis. • Bilirubin protects PASMC from apoptosis under hypoxia via ERK1/2 pathway.

The synthesis of 13C-bilirubin and its use in the validation of bilirubin kinetic studies in rats

International Nuclear Information System (INIS)

Sturrock, E.D.

1994-04-01

The total synthesis of [10- 13 C] bilirubin IXα], the principal waste product of haem degradation, is described. Site specific labelling was accomplished by the Vilsmeier formulation of one of the dipyrrolic fragments using [1- 13 C] dimethylformamide. The penultimate dehydrohalogenation reaction was complicated by a competing elimination reaction which yielded a bridged biliverdin derivative. The base catalysed reaction affords a novel [10- 13 C]-8,12-bis(2-methoxycarbonylethyl)-7,13,17-trimethyl-2,18-propano-3-vinylbilin-1,19(21H,24H)-dione in which the 2 and 18 positions of the macrocycle are bridged with a propano tether, the structure has been established using single crystal X-ray and 1 H nuclear Overhauser effect studies. [ 14 C]bilirubin was prepared, bio synthetically, using [ 14 C]aminolevulinic acid. Bilirubin kinetics in 4 rats were measured by the analysis of the plasma disappearance of [ 14 C]bilirubin in a two-compartment model. The plasma half-life of the first and second exponentials were 1.97 and 32.8 minutes respectively. The data were used to determine model independent parameters k 12 , k 21 , and k 20 . In the proposed model, plasma unconjugated bilirubin exchanges with a hepatic unconjugated bilirubin pool. Bilirubin is eliminated from the system via the proposed hepatic pool. These studies provide an analysis of the kinetics of unconjugated bilirubin in rates and are intended to serve as a reference point for studies using a stable isotope of bilirubin. The plasma disappearance of [10- 13 C]bilirubin IXα in three rats was studied using mass spectrometry to measure the bilirubin δ 13 C. Validation of the experimental procedure in terms of range and reproducibility of the detection method was carried out. The half lives of the initial and terminal exponentials were 2.27±2.5 and 22.8±12.9 minutes. Despite the large 95% confidence limits calculated for these clearance curves they serve as an important foundation for future bilirubin kinetic

Kaempferol protects against propacetamol-induced acute liver injury through CYP2E1 inactivation, UGT1A1 activation, and attenuation of oxidative stress, inflammation and apoptosis in mice.

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Tsai, Ming-Shiun; Wang, Ying-Han; Lai, Yan-Yun; Tsou, Hsi-Kai; Liou, Gan-Guang; Ko, Jiunn-Liang; Wang, Sue-Hong

2018-06-15

Acetaminophen (APAP) overdose can induce acute liver injury (ALI) with significant morbidity and mortality. Propacetamol is an APAP prodrug, which is clinically bioequivalent to APAP. Kaempferol, a dietary flavonoid, has antioxidant, anti-inflammatory, and anti-apoptotic effects. In this study, we investigated the protective effect of kaempferol on propacetamol-induced ALI and its underlying mechanism in mice. Kaempferol pretreatment (125 mg/kg) before propacetamol injection significantly decreased propacetamol-induced serum ALT and AST activities, and DNA fragmentation. Kaempferol administration also reduced propacetamol-induced oxidative stress by inhibiting thiobarbituric acid reactive substances (TBARS) and 3-nitrotyrosine (3-NT) formation partly through downregulation of cytochrome P450 2E1 (CYP2E1) expression, upregulation of UDP glucuronosyltransferase family 1 member A1 (UGT1A1) expression, restoration of the activities of antioxidant enzymes including SOD, GPx and catalase toward normal, recovery of propacetamol-suppressed Nrf2 and GCLC expressions, and maintenance of normal glutathione level. Furthermore, kaempferol markedly attenuated APAP-induced serum TNF-α and IL-6 productions, downregulated APAP-induced phosphorylations of JNK and ERK, and decreased early hepatic apoptosis via decreasing Bax/Bcl-2 ratio and caspase 3 activation. Furthermore, administration of N-acetylcysteine (NAC) and kaempferol significantly rescued more mice than a low dose of NAC only did when a lethal dose of propacetamol injected and therapized at a delayed time point. These data suggested that kaempferol protects the liver against propacetamol-induced injury through anti-oxidative, anti-inflammatory and anti-apoptotic activities. Copyright © 2018 Elsevier B.V. All rights reserved.

Change in Serum Bilirubin Level as a Predictor of Incident Metabolic Syndrome.

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Lee, You-Bin; Lee, Seung-Eun; Jun, Ji Eun; Jee, Jae Hwan; Bae, Ji Cheol; Jin, Sang-Man; Kim, Jae Hyeon

2016-01-01

Serum bilirubin level was negatively associated with the prevalence of metabolic syndrome (MetS) in previous cross-sectional studies. However, bilirubin variance preceding the development of MetS has yet to be investigated. We aimed to determine the effect of change in bilirubin concentration on the risk of incident MetS in healthy Korean adults. We conducted a retrospective longitudinal study of subjects who had undergone at least four yearly health check-ups between 2006 and 2012. Of 24,185 total individuals who received annual check-ups, 11,613 non-MetS participants with a baseline bilirubin level not exceeding 34.2 μmol/l were enrolled. We evaluated the association between percent change in bilirubin and risk of incident MetS. During 55,407 person-years of follow-up, 2,439 cases of incident MetS developed (21.0%). Baseline serum bilirubin level clearly showed no association with the development of MetS in men but an independent significant inverse association in women which attenuated (hence may be mediated) by elevated homeostatic model assessment index 2 for insulin resistance (HOMA2-IR). However, increased risk for incident MetS was observed in higher percent change in bilirubin quartiles, with hazard ratios of 2.415 (95% CI 2.094-2.785) in men and 2.156 (95% CI 1.738-2.675) in women in the fourth quartile, compared to the lowest quartile, after adjusting for age, smoking status, medication history, alanine aminotransferase, uric acid, estimated glomerular filtration rate, fasting glucose, baseline diabetes mellitus prevalence, systolic blood pressure, waist circumference, and body mass index. The hazard ratios per one standard deviation increase in percent change in bilirubin as a continuous variable were 1.277 (95% CI 1.229-1.326) in men and 1.366 (95% CI 1.288-1.447) in women. Increases in serum bilirubin concentration were positively associated with a higher risk of incident MetS. Serum bilirubin increment might be a sensitive marker for the development

Synthesis of a Benzene-containing C1-Phosphonate Analogue of UDP-GlcNAc for the Inhibition of O-GlcNAc Transferase

Energy Technology Data Exchange (ETDEWEB)

Im, Jungkyun [Soonchunhyang Univ., Asan (Korea, Republic of)

2016-01-15

I report here the design, synthesis, and biological evaluation of a new C1-phosphonate analogue of UDP-GlcNAc as a potential inhibitor of OGT, an enzyme responsible for O-GlcNAc modification. The analogue was designed to mimic the transition state of the natural donor involved in the enzymatic reaction. However, the analogue showed somehow low activity as an inhibitor of OGT.

Pulse radiolysis of bilirubin in aqueous solution

International Nuclear Information System (INIS)

Barber, D.J.W.; Richards, J.T.

1977-01-01

A pulse radiolysis study of bilirubin, the breakdown product of heme, has been made. In aqueous solution at pH 12, short-lived transient spectra have been obtained for reaction of bilirubin with e/sub aq//sup -/ and OH. Bimolecular rate constants for these reactions have been measured, namely, k/sub BR+e/sub aq//sup -/ equals 9.5 x 10 9 M -1 sec -1 and k/sub BR+OH/ equals 3.45 x 10 9 M -1 sec -1 , and the spectrum of a long-lived product resulting from decay of the bilirubin-OH adduct has been obtained. In addition, solute destruction by OH has been investigated in detail. The transient absorption spectrum for reduction of bilirubin with the H atom at neutral pH has been measured. By measuring the rate of reaction with e/sub aq//sup -/ in the presence of bovine serum albumin (BSA), the mode of binding of bilirubin to this biologically important compound has been studied

Effects of dietary components on testosterone metabolism via UDP‐glucuronosyltransferase (UGT

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Carl eJenkinson

2013-07-01

Full Text Available The potential interference in testosterone metabolism through ingested substances has ramifications for: i a range of pathologies such as prostate cancer, ii medication contra-indications, iii disruption to the endocrine system, and iv potential confounding effects on doping tests. Conjugation of anabolic steroids during phase II metabolism, mainly driven by UDP-glucuronosyltransferase (UGT 2B7, 2B15 and 2B17, has been shown to be impaired in vitro by a range of compounds including xenobiotics and pharmaceuticals. Following early reports on the effects of a range of xenobiotics on UGT activity in vitro, the work was extended to reveal similar effects with common non-steroidal anti-inflammatory drugs. Notably, recent studies have evidenced inhibitory effects of the common foodstuffs green tea and red wine, along with their constituent flavonoids and catechins. This review amalgamates the existing evidence for the inhibitory effects of various pharmaceutical and dietary substances on the rate of UGT glucuronidation of testosterone; and evaluates the potential consequences for health linked to steroid levels, interaction with treatment drugs metabolised by the UGT enzyme and steroid abuse in sport.

Association of the golgi UDP-galactose transporter with UDP-galactose: ceramide galactosyltransferase allows UDP-galactose import in the endoplasmic reticulum

NARCIS (Netherlands)

Sprong, H.; Degroote, S.; Nilsson, T.; Kawakita, M.; Ishida, N.; van der Sluijs, P.; van Meer, G.

2003-01-01

UDP-galactose reaches the Golgi lumen through the UDP-galactose transporter (UGT) and is used for the galactosylation of proteins and lipids. Ceramides and diglycerides are galactosylated within the endoplasmic reticulum by the UDP-galactose: ceramide galactosyltransferase. It is not known how

The different metabolism of morusin in various species and its potent inhibition against UDP-glucuronosyltransferase (UGT) and cytochrome p450 (CYP450) enzymes.

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Shi, Xianbao; Yang, Shuman; Zhang, Gang; Song, Yonggui; Su, Dan; Liu, Yali; Guo, Feng; Shan, Lina; Cai, Jiqun

2016-01-01

1. The aim of this study was to investigate the inhibitory effect of morusin on Glucuronosyltransferase (UGT) isoforms and cytochrome P450 enzymes (CYP450s). We also investigated the metabolism of morusin in human, rat, dog, monkey, and minipig liver microsomes. 2. 100 μM of morusin exhibited strong inhibition on all UGTs and CYP450s. The half inhibition concentration (IC50) values for CYP3A4, CYP1A2, CYP2C9, CYP2E1, UGT1A6, UGT1A7, and UGT1A8 were 2.13, 1.27, 3.18, 9.28, 4.23, 0.98, and 3.00 μM, and the inhibition kinetic parameters (Ki) were 1.34, 1.16, 2.98, 6.23, 4.09, 0.62, and 2.11 μM, respectively. 3. Metabolism of morusin exhibited significant species differences. The quantities of M1 from minipig, monkey, dog, and rat were 7.8, 11.9, 2.0, and 6.3-fold of human levels. The Km values in HLMs, RLMs, MLMs, DLMs, and PLMs were 7.84, 22.77, 14.32, 9.13, and 22.83 μM, and Vmax for these species were 0.09, 1.23, 1.43, 0.15, and 0.75 nmol/min/mg, respectively. CLint (intrinsic clearance) values (Vmax/Km) for morusin obeyed the following order: monkey > rat > minipig > dog > human. CLH (hepatic clearance) values for humans, dogs, and rats were calculated to be 8.28, 17.38, and 35.12 mL/min/kg body weight, respectively. 4. This study provided vital information to understand the inhibitory potential and metabolic behavior of morusin among various species.

Bilirubin encephalopathy

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Bilirubin encephalopathy is a rare neurological condition that occurs in some newborns with severe jaundice . ... Bilirubin encephalopathy (BE) is caused by very high levels of bilirubin. Bilirubin is a yellow pigment that is created ...

Characterization of UGT716A1 as a Multi-substrate UDP:Flavonoid Glucosyltransferase Gene in Ginkgo biloba

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Xiaojia Su

2017-12-01

Full Text Available Ginkgo biloba L., a “living fossil” and medicinal plant, is a well-known rich source of bioactive flavonoids. The molecular mechanism underlying the biosynthesis of flavonoid glucosides, the predominant flavonoids in G. biloba, remains unclear. To better understand flavonoid glucosylation in G. biloba, we generated a transcriptomic dataset of G. biloba leaf tissue by high-throughput RNA sequencing. We identified 25 putative UDP-glycosyltransferase (UGT unigenes that are potentially involved in the flavonoid glycosylation. Among them, we successfully isolated and expressed eight UGT genes in Escherichia coli, and found that recombinant UGT716A1 protein was active toward broad range of flavonoid/phenylpropanoid substrates. In particular, we discovered the first recombinant UGT protein, UGT716A1 from G. biloba, possessing unique activity toward flavanol gallates that have been extensively documented to have significant bioactivity relating to human health. UGT716A1 expression level paralleled the flavonoid distribution pattern in G. biloba. Ectopic over-expression of UGT716A1 in Arabidopsis thaliana led to increased accumulation of several flavonol glucosides. Identification and comparison of the in vitro enzymatic activity of UGT716A1 homologs revealed a UGT from the primitive land species Physcomitrella patens also showed broader substrate spectrum than those from higher plants A. thaliana, Vitis vinifera, and Medicago truncatula. The characterization of UGT716A1 from G. biloba bridges a gap in the evolutionary history of UGTs in gymnosperms. We also discuss the implication of UGT716A1 for biosynthesis, evolution, and bioengineering of diverse glucosylated flavonoids.

Prognostic impact of serum bilirubin level on long-term renal survival in IgA nephropathy.

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Tanaka, Shigeru; Ninomiya, Toshiharu; Masutani, Kosuke; Nagata, Masaharu; Tsuchimoto, Akihiro; Tsuruya, Kazuhiko; Kitazono, Takanari

2015-12-01

Serum bilirubin has been recognized as a novel endogenous antioxidant. The aim of our study was to evaluate the impact of serum bilirubin on kidney prognosis in IgA nephropathy (IgAN). We followed retrospectively 694 patients with IgAN diagnosed by renal biopsy between 1982 and 2010. The risk factors for developing end-stage renal disease (ESRD) were estimated using a Cox proportional hazard model. Predictive performance between models with or without serum bilirubin was evaluated by calculating the net reclassification improvement (NRI) and integrated discrimination improvement (IDI). Seventy-seven patients developed ESRD during the median 4.9 years of follow-up. Estimated glomerular filtration rate, proteinuria and histological severity were inversely related to bilirubin levels. In multivariate analysis, serum bilirubin was an independent risk factor for ESRD (hazard ratio for every 0.1 mg/dL decrease in serum bilirubin, 1.18; 95 % CI, 1.04-1.33). The incidence rate of ESRD decreased linearly with the increases in bilirubin levels (P for trend bilirubin was incorporated into a model with conventional ESRD risk factors, the NRI and IDI were 0.281 (P = 0.02) and 0.019 (P = 0.01), respectively. We demonstrated that lower bilirubin levels were significantly associated with higher risk of ESRD in IgAN. In addition, bilirubin provided incremental predictive value in the risk assessment for progression of IgAN beyond that provided by standard risk factors.

Role of UDP-Glucuronosyltransferase (UGT) 2B2 in Metabolism of Triiodothyronine: Effect of Microsomal Enzyme Inducers in Sprague Dawley and UGT2B2-Deficient Fischer 344 Rats

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Richardson, Terrilyn A.; Klaassen, Curtis D.

2010-01-01

Microsomal enzyme inducers (MEI) that increase UDP-glucuronosyltransferases (UGTs) can impact thyroid hormone homeostasis in rodents. Increased glucuronidation can result in reduction of serum thyroid hormone and a concomitant increase in thyroid-stimulating hormone (TSH). UGT2B2 is thought to glucuronidate triiodothyronine (T3). The purposes of this study were to determine the role of UGT2B2 in T3 glucuronidation and whether increased T3 glucuronidation mediates the increased TSH observed after MEI treatment. Sprague Dawley (SD) and UGT2B2-deficient Fischer 344 (F344) rats were fed a control diet or diet containing pregnenolone-16α-carbonitrile (PCN; 800 ppm), 3-methylcholanthrene (3-MC; 200 ppm), or Aroclor 1254 (PCB; 100 ppm) for 7 days. Serum thyroxine (T4), T3, and TSH concentrations, hepatic androsterone/T4/T3 glucuronidation, and thyroid follicular cell proliferation were determined. In both SD and F344 rats, MEI treatments decreased serum T4, whereas serum T3 was maintained (except with PCB treatment). Hepatic T4 glucuronidation increased significantly after MEI in both rat strains. Compared with the other MEI, only PCN treatment significantly increased T3 glucuronidation (281 and 497%) in both SD and UGT2B2-deficient F344 rats, respectively, and increased both serum TSH and thyroid follicular cell proliferation. These data demonstrate an association among increases in T3 glucuronidation, TSH, and follicular cell proliferation after PCN treatment, suggesting that T3 is glucuronidated by other PCN-inducible UGTs in addition to UGT2B2. These data also suggest that PCN (rather than 3-MC or PCB) promotes thyroid tumors through excessive TSH stimulation of the thyroid gland. PMID:20421340

Evaluation of bisphenol A glucuronidation according to UGT1A1*28 polymorphism by a new LC–MS/MS assay

International Nuclear Information System (INIS)

Trdan Lušin, Tina; Roškar, Robert; Mrhar, Aleš

2012-01-01

The endocrine disruptor bisphenol A (BPA) is a frequently used chemical in the manufacture of consumer products. In humans, BPA is extensively metabolized to BPA glucuronide (BPAG) by different UDP-glucuronosyltransferase (UGT) isoforms. The study has been performed with the intention to improve the accuracy of published physiologically based pharmacokinetic models and to improve regulatory risk assessments of BPA. In order to gain insight into intestine, kidney, liver, and lung glucuronidation of BPA, human microsomes of all tested organs were used. BPAG formation followed Michaelis–Menten kinetics in the intestine and kidney, but followed substrate inhibition kinetics in the liver. Human lung microsomes did not show glucuronidation activity towards BPA. While the liver intrinsic clearance was very high (857 mL min −1 kg body weight −1 ), the tissue intrinsic clearances for the kidney and intestine were less than 1% of liver intrinsic clearance. Since BPA is a UGT1A1 substrate, we postulated that the common UGT1A1*28 polymorphism influences BPA glucuronidation, and consequently, BPA detoxification. Hepatic tissue intrinsic clearances for UGT1A1*1/*1, UGT1A1*1/*28, and UGT1A1*28/*28 microsomes were 1113, 1075, and 284 mL min −1 kg body weight −1 , respectively. Prior to microsomal experiments, the bioproduction of BPAG and stable isotope-labeled BPAG (BPAG d16 ) was performed for the purpose of the reliable and accurate quantification of BPAG. In addition, a sensitive LC–MS/MS analytical method for the simultaneous determination of BPA and BPAG based on two stable isotope-labeled internal standards was developed and validated. In conclusion, our in vitro results show that the liver is the main site of BPA glucuronidation (K m 8.9 μM, V max 8.5 nmol min −1 mg −1 ) and BPA metabolism may be significantly influenced by a person's genotype (K m 10.0–13.1 μM, V max 3.4–16.2 nmol min −1 mg −1 ). This discovery may be an important fact for the

Prognostic significance of serum bilirubin in stroke

International Nuclear Information System (INIS)

Arslan, A.; Ismail, M.; Khan, F.; Khan, A.; Khattak, M.B.; Anwar, M.J.

2011-01-01

Background: Oxidative injury is an important cause of the neurologic lesion in stroke. Serum bilirubin is considered a natural antioxidant that may affect the prognosis of stroke. The purpose of this study was to evaluate the prognostic significance of bilirubin in stroke patients. Methods: A prospective cross-sectional study was conducted in Medical Units of Khyber Teaching Hospital, Peshawar. Inpatients admitted with acute attack of stroke were included in this study. Data regarding serum bilirubin and concurrent cerebrovascular risk factors were collected. National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) were used to analyse stroke's severity and functional outcomes, respectively. Results: Hypertension, diabetes mellitus and heart diseases were the most common risk factors. Patients were divided into 3 groups on the basis of serum bilirubin, i.e., =0.6 mg/dl (Group-1), 0.7-0.9 mg/dl (Group-2), and =1.0 mg/dl (Group-3). The mean pre-hospitalisation NIHSS score for Groups 1, 2 and 3 was 5.62, 11.66 and 25.33, respectively; and post-hospitalisation score was 0.875, 3.76 and 16.26, respectively. The pre-hospitalisation mRS score was 4 for Group-1, 4.52 for Group-2 and 4.93 for Group-3; while post-hospitalisation Mrs Score was 1.50, 2.38 and 4.26, respectively. Average serum bilirubin level was significantly higher in patients with poor outcomes as compared with good outcomes (p<0.01). Conclusions: This study suggests that higher serum bilirubin levels were associated with increased stroke severity, longer hospitalisation and poor prognosis. (author)

Study of MRI characteristics of newborn bilirubin encephalopathy

International Nuclear Information System (INIS)

Wu Wulin; Wang Xiaoyi; Liao Weihua; Liu Fan; Zhang Ping

2008-01-01

Objective: To explore routine magnetic resonance imaging characteristics of newborn bilirubin encephalopathy (NBE). Methods: MRI features and clinical data of 17 patients with Newborn bilirubin encephalopathy were retrospectively analyzed, globus pallidus (GP)and subthalamic signal intensity was evaluated. The increase of GP signal intensity and serum total bilirubin peak value were analyzed using pearson correlation analysis. Serum total bilirubin peak value between patients with high signal in the subthalamic nuclei on T 1 WI and patients without high signal in the subthalamic nuclei were compared statistically. Results: The main MRI presentation in the NBE group was abnormally increased signal intensity in the GP on T 1 WI, which was not apparent on T 2 WI. One patient showed abnormal high signal intensity in the posteromedial part of GP. Nine patients had high signal in the subthalamic nuclei on T 1 WI and normal signal on T 2 WI. Four patients showed high signal in the brainstem with sparing of dorsal pontine. The increase in value of GP signal intensity was 249.0-423.8 in 12 patients and their serum total bilirubin peak values were 366.0-983.3 μmol/L. A positive correlation was found between increase of GP signal intensity and serum total bilirubin peak value. The serum total bilirubin level of abnormal subthalamic group and normal subthalamic group were 660.7±192.4 μmol/L and 513.3±107.51 μmol/L respectively. The difference between the two groups was not statistically significant (t=1.914, P>0.05). Conclusion: The routine MRI has some characteristics and is useful in the diagnosis of newborn bilirubin encephalopathy. (authors)

Blood Test: Bilirubin

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... Videos for Educators Search English Español Blood Test: Bilirubin KidsHealth / For Parents / Blood Test: Bilirubin What's in ... liver or kidneys) is working. What Is a Bilirubin Test? A bilirubin test measures how much bilirubin ...

Bilirubin Binding to PPARα Inhibits Lipid Accumulation

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Stec, David E.; John, Kezia; Trabbic, Christopher J.; Luniwal, Amarjit; Hankins, Michael W.; Baum, Justin

2016-01-01

Numerous clinical and population studies have demonstrated that increased serum bilirubin levels protect against cardiovascular and metabolic diseases such as obesity and diabetes. Bilirubin is a potent antioxidant, and the beneficial actions of moderate increases in plasma bilirubin have been thought to be due to the antioxidant effects of this bile pigment. In the present study, we found that bilirubin has a new function as a ligand for PPARα. We show that bilirubin can bind directly to PPARα and increase transcriptional activity. When we compared biliverdin, the precursor to bilirubin, on PPARα transcriptional activation to known PPARα ligands, WY 14,643 and fenofibrate, it showed that fenofibrate and biliverdin have similar activation properties. Treatment of 3T3-L1 adipocytes with biliverdin suppressed lipid accumulation and upregulated PPARα target genes. We treated wild-type and PPARα KO mice on a high fat diet with fenofibrate or bilirubin for seven days and found that both signal through PPARα dependent mechanisms. Furthermore, the effect of bilirubin on lowering glucose and reducing body fat percentage was blunted in PPARα KO mice. These data demonstrate a new function for bilirubin as an agonist of PPARα, which mediates the protection from adiposity afforded by moderate increases in bilirubin. PMID:27071062

Elevated bilirubin levels are associated with a better renal prognosis and ameliorate kidney fibrosis.

Science.gov (United States)

Park, Sehoon; Kim, Do Hyoung; Hwang, Jin Ho; Kim, Yong-Chul; Kim, Jin Hyuk; Lim, Chun Soo; Kim, Yon Su; Yang, Seung Hee; Lee, Jung Pyo

2017-01-01

Bilirubin has been reported to protect against kidney injury. However, further studies highlighting the beneficial effects of bilirubin on renal fibrosis and chronic renal function decline are necessary. We assessed a prospective cohort with a reference range of total bilirubin levels. The primary outcome was a 30% reduction in the estimated glomerular filtration rate (eGFR) from baseline, and the secondary outcome was a doubling of the serum creatinine levels, halving of the eGFR and the initiation of dialysis. In addition, experiments with tubular epithelial cells and C57BL/6 mice were performed to investigate the protective effects of bilirubin on kidney fibrosis. As a result, 1,080 patients were included in the study cohort. The study group with relative hyperbilirubinemia (total bilirubin 0.8-1.2 mg/dL) showed a better prognosis in terms of the primary outcome (adjusted hazard ratio (HR) 0.33, 95% confidence interval (CI) 0.19-0.59, P bilirubin-treated mice showed less fibrosis in the unilateral ureteral obstruction (UUO) model (P bilirubin treatment decreased fibronectin expression in tubular epithelial cells in a dose-dependent manner (P bilirubin levels were associated with better renal prognosis, and bilirubin treatment induced a beneficial effect on renal fibrosis. Therefore, bilirubin could be a potential therapeutic target to delay fibrosis-related kidney disease progression.

Bilirubin - urine

Science.gov (United States)

Conjugated bilirubin - urine; Direct bilirubin - urine ... Bilirubin is not normally found in the urine. ... Increased levels of bilirubin in the urine may be due to: Biliary tract disease Cirrhosis Gallstones in the biliary tract Hepatitis Liver disease ...

Three-dimensionally porous graphene: A high-performance adsorbent for removal of albumin-bonded bilirubin.

Science.gov (United States)

Ma, Chun Fang; Gao, Qiang; Xia, Kai Sheng; Huang, Zhi Yuan; Han, Bo; Zhou, Cheng Gang

2017-01-01

The development of bilirubin adsorbents with high adsorption efficiencies towards albumin-bonded bilirubin is still a considerable challenge. In this work, a three-dimensionally porous graphene (3D-pGR) has been fabricated through a simple carbon dioxide (CO 2 ) activation of thermally exfoliated graphite oxide (EGO). Intriguingly, the resultant 3D-pGR material showed hierarchically micro-meso-macroporous structure, high specific surface area of up to 843m 2 g -1 , and large pore volume as high as 2.71cm 3 g -1 . Besides, the large planar π-configuration structure of 3D-pGR made it possible to compete effectively with albumin for bilirubin binding. Taking advantages of these fantastic characteristics, the 3D-pGR was demonstrated to be extraordinarily efficient for bilirubin removal from a bovine serum albumin (BSA)-rich solution. Under optimized conditions, the maximum adsorption capacity of 3D-pGR for BSA-bonded bilirubin was up to 126.1mgg -1 , which is not only significantly higher than the adsorption capacities of currently available adsorbents towards albumin-bonded bilirubin, but also superior to those of many reported adsorbents towards free bilirubin. In addition, the hemolysis assay of 3D-pGR indicated that this material had negligible hemolysis effect. Findings from this study may open up important new possibilities for removal of protein-bonded toxins. Copyright © 2016 Elsevier B.V. All rights reserved.

The treatment of crigler-najjar syndrome by blue light as explained by resonant recognition model

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Cosic Irena

2016-12-01

However, the blue light treatment is less effective with ageing, due to decrease of the blue lightpenetration through skin. Thus, there is a need for alternative treatments. Here, we propose to design de-novopeptide, using this specific RRM frequency. Such peptide, according to RRM, is proposed to have the samebiological function as UDP glucuronosyltransferase 1-A1 and thus can be used for alternative treatment of Crigler-Najjar syndrome.

Newborn Jaundice Technologies: Unbound Bilirubin and Bilirubin Binding Capacity In Neonates

Science.gov (United States)

Amin, Sanjiv B.; Lamola, Angelo A.

2011-01-01

Neonatal jaundice (hyperbilirubinemia), extremely common in neonates, can be associated with neurotoxicity. A safe level of bilirubin has not been defined in either premature or term infants. Emerging evidence suggest that the level of unbound (or “free”) bilirubin has a better sensitivity and specificity than total serum bilirubin for bilirubin-induced neurotoxicity. Although recent studies suggest the usefulness of free bilirubin measurements in managing high-risk neonates including premature infants, there currently exists no widely available method to assay the serum free bilirubin concentration. To keep pace with the growing demand, in addition to reevaluation of old methods, several promising new methods are being developed for sensitive, accurate, and rapid measurement of free bilirubin and bilirubin binding capacity. These innovative methods need to be validated before adopting for clinical use. We provide an overview of some promising methods for free bilirubin and binding capacity measurements with the goal to enhance research in this area of active interest and apparent need. PMID:21641486

UDP-glucose pyrophosphorylase from tubers of Jerusalem artichoke (Helianthus tuberosus L.)

International Nuclear Information System (INIS)

Otozai, Kiyotaka; Taniguchi, Hajime; Nakamura, Michinori

1973-01-01

UDP-glucose pyrophosphorylase of Jerusalem artichoke tubers was purified 90-fold over the crude extract. The purified enzyme preparation absolutely required magnesium ions for activity. Cobalt ions were 60% as effective as magnesium ions; other divalent cations including manganese showed little or no effect. This enzyme had a pH optimum of 8.5 and a temperature optimum of 40 deg C. ATP and UDP inhibited the activity of this enzyme in both forward and backward directions. Km values for UDP-glucose, inorganic pyrophosphate, glucose-1-phosphate - 14 C and UTP were determined to be 4.45 x 10 -4 , 2.33 x 10 -4 , 9.38 x 10 -4 and 2.98 x 10 -4 M, respectively. These results are discussed in comparison with those of UDP-glucose pyrophosphorylases isolated from other plants. (author)

Reduced total serum bilirubin levels are associated with ulcerative colitis.

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Kathleen M Schieffer

Full Text Available Chronic inflammation associated with inflammatory bowel disease (IBD results in increased oxidative stress that damages the colonic microenvironment. Low levels of serum bilirubin, an endogenous antioxidant, have been associated with increased risk for Crohn's disease (CD. Therefore, the aim of this study was to examine whether total serum bilirubin levels are associated with ulcerative colitis (UC. We identified a retrospective case-control population (n = 6,649 from a single tertiary care center, Penn State Hershey Medical Center (PSU and a validation cohort (n = 1,996 from Virginia Commonwealth University Medical Center (VCU. Cases were age- and sex-matched to controls (PSU: CD n = 254, UC n = 187; VCU: CD n = 233, UC n = 124. Total serum bilirubin levels were obtained from de-identified medical records and segregated into quartiles. Logistic regression analysis was performed on each quartile of total serum bilirubin compared to the last quartile (highest bilirubin levels to determine the association of total serum bilirubin with UC. Similar to CD patients, UC patients demonstrated reduced levels of total serum bilirubin compared to controls at PSU and VCU. The lowest quartile of total serum bilirubin was independently associated with UC for the PSU (OR: 1.98 [95% CI: 1.09-3.63] and VCU cohorts (OR: 6.07 [95% CI: 3.01-12.75]. Lower levels of the antioxidant bilirubin may reduce the capability of UC patients to remove reactive oxygen species leading to an increase in intestinal injury. Therapeutics that reduce oxidative stress may be beneficial for these patients.

Animal pigment bilirubin discovered in plants.

Science.gov (United States)

Pirone, Cary; Quirke, J Martin E; Priestap, Horacio A; Lee, David W

2009-03-04

The bile pigment bilirubin-IXalpha is the degradative product of heme, distributed among mammals and some other vertebrates. It can be recognized as the pigment responsible for the yellow color of jaundice and healing bruises. In this paper we present the first example of the isolation of bilirubin in plants. The compound was isolated from the brilliant orange-colored arils of Strelitzia nicolai, the white bird of paradise tree, and characterized by HPLC-ESMS, UV-visible, (1)H NMR, and (13)C NMR spectroscopy, as well as comparison with an authentic standard. This discovery indicates that plant cyclic tetrapyrroles may undergo degradation by a previously unknown pathway. Preliminary analyses of related plants, including S. reginae, the bird of paradise, also revealed bilirubin in the arils and flowers, indicating that the occurrence of bilirubin is not limited to a single species or tissue type.

Plasma bilirubin values on admission and ventricular remodeling after a first anterior ST-segment elevation acute myocardial infarction.

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Miranda, Berta; Barrabés, José A; Figueras, Jaume; Pineda, Victor; Rodríguez-Palomares, José; Lidón, Rosa-Maria; Sambola, Antonia; Bañeras, Jordi; Otaegui, Imanol; García-Dorado, David

2016-01-01

Bilirubin may elicit cardiovascular protection and heme oxygenase-1 overexpression attenuated post-infarction ventricular remodeling in experimental animals, but the association between bilirubin levels and post-infarction remodeling is unknown. In 145 patients with a first anterior ST-segment elevation acute myocardial infarction (STEMI), we assessed whether plasma bilirubin on admission predicted adverse remodeling (left ventricular end-diastolic volume [LVEDV] increase ≥20% between discharge and 6 months, estimated by magnetic resonance imaging). Patients' baseline characteristics and management were comparable among bilirubin tertiles. LVEDV increased at 6 months (P bilirubin tertiles (10.8 [30.2], 10.1 [22.9], and 12.7 [24.3]%, P = 0.500). Median (25-75 percentile) bilirubin values in patients with and without adverse remodeling were 0.75 (0.60-0.93) and 0.73 (0.60-0.92) mg/dL (P = 0.693). Absence of final TIMI flow grade 3 (odds ratio 3.92, 95% CI 1.12-13.66) and a history of hypertension (2.04, 0.93-4.50), but not admission bilirubin, were independently associated with adverse remodeling. Bilirubin also did not predict the increase in ejection fraction at 6 months. Admission bilirubin values are not related to LVEDV or ejection fraction progression after a first anterior STEMI and do not predict adverse ventricular remodeling. Key messages Bilirubin levels are inversely related to cardiovascular disease, and overexpression of heme oxygenase-1 (the enzyme that determines bilirubin production) has prevented post-infarction ventricular remodeling in experimental animals, but the association between bilirubin levels and the progression of ventricular volumes and function in patients with acute myocardial infarction remained unexplored. In this cohort of patients with a first acute anterior ST-segment elevation myocardial infarction receiving contemporary management, bilirubin levels on admission were not predictive of the changes in left

The Relationship between Serum Bilirubin and Elevated Fibrotic Indices among HBV Carriers: A Cross-Sectional Study of a Chinese Population

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Min Du

2016-12-01

Full Text Available The study probed the association between bilirubin and hepatitis B virus (HBV infection and progression. A cross-sectional analysis of 28,500 middle aged and elderly Chinese participants was performed to analyze the differences of bilirubin in terms of hepatitis B surface antigen (HBsAg positive or negative and the correlation between bilirubin and severity of hepatic fibrosis estimated by non-invasive indices. Bilirubin was significantly higher in the HBsAg (+ group than the HBsAg (− group. Higher bilirubin levels were consistently associated with elevated liver fibrosis indices among HBsAg carriers. Compared with quartile 1 of total bilirubin (TBil, the multivariable-adjusted ORs (95% CIs for elevated fibrosis indices of quartile 4 were 2.24 (95% CIs, 1.57–3.21 estimated by fibrosis 4 score (FIB-4 and 2.22 (95% CIs, 1.60–3.08 estimated by aspartate transaminase to platelet ratio index (APRI. In addition, direct bilirubin (DBil had a stronger association with elevated liver fibrosis indices than did indirect bilirubin (IBil. Furthermore, the relationship between DBil and elevated fibrosis indices was more robust among participants who were female, overweight or had central fat distribution. These findings suggested that bilirubin levels, especially DBil, were independently associated with an increased risk of increased fibrosis indices.

Serum Bilirubin Concentrations in Patients With Takayasu Arteritis.

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Peng, You-Fan; Deng, Yi-Bin

2017-06-01

- Bilirubin has strong anti-inflammatory and antioxidative stress action. Progression of inflammation involving arteries is a crucial activator in pathogenesis of Takayasu arteritis (TA). - To investigate the relationship between serum bilirubin and TA. - Our study involved 115 consecutive TA patients. Patients with active-phase disease were followed and received prednisone therapy. - Lower concentrations of serum bilirubin were detected in TA patients compared with healthy subjects (0.6 ± 0.31 versus 0.7 ± 0.22 mg/dL, P = .02). Serum bilirubin concentrations in active TA patients were lower than those in inactive patients (0.5 ± 0.20 versus 0.8 ± 0.32 mg/dL, P bilirubin correlated positively with total protein (r = 0.193, P = .04) and negatively with C-reactive protein and erythrocyte sedimentation rate (r = -0.213, P = .03, and r = -0.532, P bilirubin was associated with a 1.10 times increase in the odds for TA compared with the controls (odds ratio = 0.913, 95% CI, 0.856-0.974; P = .006). Serum bilirubin was correlated with erythrocyte sedimentation rate (β = -0.170, P bilirubin in predicting active TA patients was 0.802. Serum bilirubin levels were found to be significantly increased after prednisone treatment (0.5 ± 0.20 versus 0.7 ± 0.15 mg/dL, P = .002). - Lower serum bilirubin levels are associated with TA, and serum bilirubin may be influenced by prednisone therapy in active TA patients. Serum bilirubin levels in TA patients correlate negatively with erythrocyte sedimentation rate.

Functionalized SBA-15 materials for bilirubin adsorption

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Tang, Tao; Zhao, Yanling; Xu, Yao; Wu, Dong; Xu, Jun; Deng, Feng

2011-05-01

To investigate the driving force for bilirubin adsorption on mesoporous materials, a comparative study was carried out between pure siliceous SBA-15 and three functionalized SBA-15 mesoporous materials: CH 3-SBA-15 (MS), NH 2-SBA-15 (AS), and CH 3/NH 2-SBA-15 (AMS) that were synthesized by one-pot method. The obtained materials exhibited large surface areas (553-810 m 2/g) and pore size (6.6-7.1 nm) demonstrated by XRD and N 2-ad/desorption analysis. The SEM images showed that the materials had similar fiberlike morphology. The functionalization extent was calculated according to 29Si MAS NMR spectra and it was close to the designed value (10%). The synthesized mesoporous materials were used as bilirubin adsorbents and showed higher bilirubin adsorption capacities than the commercial active carbon. The adsorption capacities of amine functionalized samples AMS and AS were larger than those of pure siliceous SBA-15 and MS, indicating that electrostatic interaction was the dominant driving force for bilirubin adsorption on mesoporous materials. Increasing the ionic strength of bilirubin solution by adding NaCl would decrease the bilirubin adsorption capacity of mesoporous material, which further demonstrated that the electrostatic interaction was the dominant driving force for bilirubin adsorption. In addition, the hydrophobic interaction provided by methyl groups could promote the bilirubin adsorption.

Statin Lactonization by Uridine 5'-Diphospho-glucuronosyltransferases (UGTs).

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Schirris, Tom J J; Ritschel, Tina; Bilos, Albert; Smeitink, Jan A M; Russel, Frans G M

2015-11-02

Statins are cholesterol-lowering drugs that have proven to be effective in lowering the risk of major cardiovascular events. Although well tolerated, statin-induced myopathies are the most common side effects. Compared to their pharmacologically active acid form, statin lactones are more potent inducers of toxicity. They can be formed by glucuronidation mediated by uridine 5'-diphospho-glucuronosyltransferases (UGTs), but a systematic characterization of subtype specificity and kinetics of lactonization is lacking. Here, we demonstrate for six clinically relevant statins that only UGT1A1, 1A3, and 2B7 contribute significantly to their lactonization. UGT1A3 appeared to have the highest lactonization capacity with marked differences in statin conversion rates: pitavastatin ≫ atorvastatin > cerivastatin > lovastatin > rosuvastatin (simvastatin not converted). Using in silico modeling we could identify a probable statin interaction region in the UGT binding pocket. Polymorphisms in these regions of UGT1A1, 1A3, and 2B7 may be a contributing factor in statin-induced myopathies, which could be used in personalization of statin therapy with improved safety.

Tomato UDP-Glucose Sterol Glycosyltransferases: A Family of Developmental and Stress Regulated Genes that Encode Cytosolic and Membrane-Associated Forms of the Enzyme

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Karla Ramirez-Estrada

2017-06-01

Full Text Available Sterol glycosyltransferases (SGTs catalyze the glycosylation of the free hydroxyl group at C-3 position of sterols to produce sterol glycosides. Glycosylated sterols and free sterols are primarily located in cell membranes where in combination with other membrane-bound lipids play a key role in modulating their properties and functioning. In contrast to most plant species, those of the genus Solanum contain very high levels of glycosylated sterols, which in the case of tomato may account for more than 85% of the total sterol content. In this study, we report the identification and functional characterization of the four members of the tomato (Solanum lycopersicum cv. Micro-Tom SGT gene family. Expression of recombinant SlSGT proteins in E. coli cells and N. benthamiana leaves demonstrated the ability of the four enzymes to glycosylate different sterol species including cholesterol, brassicasterol, campesterol, stigmasterol, and β-sitosterol, which is consistent with the occurrence in their primary structure of the putative steroid-binding domain found in steroid UDP-glucuronosyltransferases and the UDP-sugar binding domain characteristic for a superfamily of nucleoside diphosphosugar glycosyltransferases. Subcellular localization studies based on fluorescence recovery after photobleaching and cell fractionation analyses revealed that the four tomato SGTs, like the Arabidopsis SGTs UGT80A2 and UGT80B1, localize into the cytosol and the PM, although there are clear differences in their relative distribution between these two cell fractions. The SlSGT genes have specialized but still largely overlapping expression patterns in different organs of tomato plants and throughout the different stages of fruit development and ripening. Moreover, they are differentially regulated in response to biotic and abiotic stress conditions. SlSGT4 expression increases markedly in response to osmotic, salt, and cold stress, as well as upon treatment with abscisic

Association between bilirubin and risk of Non-Alcoholic Fatty Liver Disease based on a prospective cohort study.

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Tian, Jianbo; Zhong, Rong; Liu, Cheng; Tang, Yuhan; Gong, Jing; Chang, Jiang; Lou, Jiao; Ke, Juntao; Li, Jiaoyuan; Zhang, Yi; Yang, Yang; Zhu, Ying; Gong, Yajie; Xu, Yanyan; Liu, Peiyi; Yu, Xiao; Xiao, Lin; Du, Min; Yang, Ling; Yuan, Jing; Wang, Youjie; Chen, Weihong; Wei, Sheng; Liang, Yuan; Zhang, Xiaomin; He, Meian; Wu, Tangchun; Yao, Ping; Miao, Xiaoping

2016-08-03

The study aimed to assess the association between total, direct, and indirect bilirubin and nonalcoholic fatty live disease (NAFLD) risk given its high prevalence and serious clinical prognosis. Among 27,009 subjects who participated in a healthy screening program from the Dongfeng-Tongji cohort study in 2008, 8189 eligible subjects (aged 35-86 years; males, 43.95%) were ultimately enrolled. The incidence rates of NAFLD in 2013 were compared with respect to baseline bilirubin levels among subjects free of NAFLD, and the effect sizes were estimated by logistic regression analysis. During 5 years follow-up, we observed 1956 cases of newly developed NAFLD with the overall incidence of 23.88%. Direct bilirubin was presented to inversely associate with NAFLD risk. Compared with quartile 1 of direct bilirubin, the multivariable-adjusted ORs (95% CIs) for NAFLD of quartile 2 to 4 were 1.104 (0.867-1.187), 0.843 (0.719-0.989), and 0.768 (0.652-0.905), respectively, P for trend 0.002). Similarly, inverse effects of direct bilirubin on NAFLD incidence were also observed when stratified by sex and BMI. However, no significant associations were found between total, and indirect bilirubin and NAFLD risk. Direct bilirubin reduced NAFLD risk independent of possible confounders among middle-aged and elderly Chinese population, probably based on the endogenous antioxidation of bilirubin.

Yinchenhao Decoction Ameliorates Alpha-Naphthylisothiocyanate Induced Intrahepatic Cholestasis in Rats by Regulating Phase II Metabolic Enzymes and Transporters

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Ya-Xiong Yi

2018-05-01

Full Text Available Yinchenhao Decoction (YCHD, a famous traditional Chinese formula, has been used for treating cholestasis for 1000s of years. The cholagogic effect of YCHD has been widely reported, but its pharmacodynamic material and underlying therapeutic mechanism remain unclear. By using ultra-high-performance liquid chromatography (UHPLC-quadrupole time-of-flight mass spectrometry, 11 original active components and eight phase II metabolites were detected in rats after oral administration of YCHD, including three new phase II metabolites. And it indicated that phase II metabolism was one of the major metabolic pathway for most active components in YCHD, which was similar to the metabolism process of bilirubin. It arouses our curiosity that whether the metabolism process of YCHD has any relationship with its cholagogic effects. So, a new method for simultaneous quantitation of eight active components and four phase II metabolites of rhein, emodin, genipin, and capillarisin has been developed and applied for their pharmacokinetic study in both normal and alpha-naphthylisothiocyanate (ANIT-induced intrahepatic cholestasis rats. The results indicated the pharmacokinetic behaviors of most components of YCHD were inhibited, which was hypothesized to be related to different levels of metabolic enzymes and transporters in rat liver. So dynamic changes of intrahepatic enzyme expression in cholestasis and YCHD treated rats have been monitored by an UHPLC-tandem mass spectrometry method. The results showed expression levels of UDP-glucuronosyltransferase 1-1 (UGT1A1, organic anion-transporting polypeptide 1A4 (OATP1A4, multidrug resistance-associated protein 2 (MRP2, multidrug resistance protein 1, sodium-dependent taurocholate cotransporter, and organic anion-transporting polypeptide 1A2 were significantly inhibited in cholestasis rats, which would account for reducing the drug absorption and the metabolic process of YCHD in cholestatic rats. A high dose (12 g/kg of

Ultra-deep pyrosequencing (UDPS data treatment to study amplicon HCV minor variants.

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Josep Gregori

Full Text Available We have investigated the reliability and reproducibility of HCV viral quasispecies quantification by ultra-deep pyrosequencing (UDPS methods. Our study has been divided in two parts. First of all, by UDPS sequencing of clone mixes samples we have established the global noise level of UDPS and fine tuned a data treatment workflow previously optimized for HBV sequence analysis. Secondly, we have studied the reproducibility of the methodology by comparing 5 amplicons from two patient samples on three massive sequencing platforms (FLX+, FLX and Junior after applying the error filters developed from the clonal/control study. After noise filtering the UDPS results, the three replicates showed the same 12 polymorphic sites above 0.7%, with a mean CV of 4.86%. Two polymorphic sites below 0.6% were identified by two replicates and one replicate respectively. A total of 25, 23 and 26 haplotypes were detected by GS-Junior, GS-FLX and GS-FLX+. The observed CVs for the normalized Shannon entropy (Sn, the mutation frequency (Mf, and the nucleotidic diversity (Pi were 1.46%, 3.96% and 3.78%. The mean absolute difference in the two patients (5 amplicons each, in the GS-FLX and GS-FLX+, were 1.46%, 3.96% and 3.78% for Sn, Mf and Pi. No false polymorphic site was observed above 0.5%. Our results indicate that UDPS is an optimal alternative to molecular cloning for quantitative study of HCV viral quasispecies populations, both in complexity and composition. We propose an UDPS data treatment workflow for amplicons from the RNA viral quasispecies which, at a sequencing depth of at least 10,000 reads per strand, enables to obtain sequences and frequencies of consensus haplotypes above 0.5% abundance with no erroneous mutations, with high confidence, resistant mutants as minor variants at the level of 1%, with high confidence that variants are not missed, and highly confident measures of quasispecies complexity.

Characterization of mouse UDP-glucose pyrophosphatase, a Nudix hydrolase encoded by the Nudt14 gene

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Heyen, Candy A.; Tagliabracci, Vincent S.; Zhai, Lanmin [Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202 (United States); Roach, Peter J., E-mail: proach@iupui.edu [Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202 (United States)

2009-12-25

Recombinant mouse UDP-glucose pyrophosphatase (UGPPase), encoded by the Nudt14 gene, was produced in Escherichia coli and purified close to homogeneity. The enzyme catalyzed the conversion of [{beta}-{sup 32}P]UDP-glucose to [{sup 32}P]glucose-1-P and UMP, confirming that it hydrolyzed the pyrophosphate of the nucleoside diphosphate sugar to generate glucose-1-P and UMP. The enzyme was also active toward ADP-ribose. Activity is dependent on the presence of Mg{sup 2+} and was greatest at alkaline pH above 8. Kinetic analysis indicated a K{sub m} of {approx}4 mM for UDP-glucose and {approx}0.3 mM for ADP-ribose. Based on V{sub max}/K{sub m} values, the enzyme was {approx}20-fold more active toward ADP-ribose. UGPPase behaves as a dimer in solution and can be cross-linked to generate a species of M{sub r} 54,000 from a monomer of 30,000 as judged by SDS-PAGE. The dimerization was not affected by the presence of glucose-1-P or UDP-glucose. Using antibodies raised against the recombinant protein, Western analysis indicated that UGPPase was widely expressed in mouse tissues, including skeletal muscle, liver, kidney, heart, lung, fat, heart and pancreas with a lower level in brain. It was generally present as a doublet when analyzed by SDS-PAGE, suggesting the occurrence of some form of post-translational modification. Efforts to interconvert the species by adding or inhibiting phosphatase activity were unsuccessful, leaving the nature of the modification unknown. Sequence alignments and database searches revealed related proteins in species as distant as Drosophila melanogaster and Caenorhabditis elegans.

Comparison of Transcutaneous Bilirubin Measurement With Total Serum Bilirubin Levels in Preterm Neonates Receiving Phototherapy.

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Pendse, Amruta; Jasani, Bonny; Nanavati, Ruchi; Kabra, Nandkishor

2017-08-15

To compare transcutaneous bilirubin with total serum bilirubin in preterm neonates after initiation of phototherapy. Jaundice was assessed in 30 preterm neonates with transcutaneous bilirubin and total serum bilirubin before initiation of phototherapy and at 12 hr after initiation of phototherapy. A photo-occlusive patch was applied over the sternum. Transcutaneous bilirubin has a good correlation with total serum bilirubin after initiation of phototherapy. (r=0.918, Pbilirubin at 28-32 weeks of gestation (r = 0.97) was better correlated with total serum bilirubin than those at 32-37 weeks (r =0.88). The correlation was better for neonates 72 hours of age (r = 0.82). Transcutaneous bilirubin correlates significantly with total serum bilirubin at the patched sternal site after initiation of phototherapy in preterm neonates.

Bilirubin Increases Insulin Sensitivity by Regulating Cholesterol Metabolism, Adipokines and PPARγ Levels

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Liu, Jinfeng; Dong, Huansheng; Zhang, Yong; Cao, Mingjun; Song, Lili; Pan, Qingjie; Bulmer, Andrew; Adams, David B.; Dong, Xiao; Wang, Hongjun

2015-01-01

Obesity can cause insulin resistance and type 2 diabetes. Moderate elevations in bilirubin levels have anti-diabetic effects. This study is aimed at determining the mechanisms by which bilirubin treatment reduces obesity and insulin resistance in a diet-induced obesity (DIO) mouse model. DIO mice were treated with bilirubin or vehicle for 14 days. Body weights, plasma glucose, and insulin tolerance tests were performed prior to, immediately, and 7 weeks post-treatment. Serum lipid, leptin, adiponectin, insulin, total and direct bilirubin levels were measured. Expression of factors involved in adipose metabolism including sterol regulatory element-binding protein (SREBP-1), insulin receptor (IR), and PPARγ in liver were measured by RT-PCR and Western blot. Compared to controls, bilirubin-treated mice exhibited reductions in body weight, blood glucose levels, total cholesterol (TC), leptin, total and direct bilirubin, and increases in adiponectin and expression of SREBP-1, IR, and PPARγ mRNA. The improved metabolic control achieved by bilirubin-treated mice was persistent: at two months after treatment termination, bilirubin-treated DIO mice remained insulin sensitive with lower leptin and higher adiponectin levels, together with increased PPARγ expression. These results indicate that bilirubin regulates cholesterol metabolism, adipokines and PPARγ levels, which likely contribute to increased insulin sensitivity and glucose tolerance in DIO mice. PMID:26017184

Serum total bilirubin levels and coronary heart disease--Causal association or epiphenomenon?

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Kunutsor, Setor K

2015-12-01

Observational epidemiological evidence supports a linear inverse and independent association between serum total bilirubin levels and coronary heart disease (CHD) risk, but whether this association is causal remains to be ascertained. A Mendelian randomization approach was employed to test whether serum total bilirubin is causally linked to CHD. The genetic variant rs6742078--well known to specifically modify levels of serum total bilirubin and accounting for up to 20% of the variance in circulating serum total bilirubin levels--was used as an instrumental variable. In pooled analysis of estimates reported from published genome-wide association studies, every copy of the T allele of rs6742078 was associated with 0.42 standard deviation (SD) higher levels of serum total bilirubin (95% confidence interval, 0.40 to 0.43). Based on combined data from the Coronary Artery Disease Genome wide Replication and Meta-analyses and the Coronary Artery Disease (C4D) Genetics Consortium involving a total of 36,763 CHD cases and 76,997 controls, the odds ratio for CHD per copy of the T allele was 1.01 (95% confidence interval, 0.99 to 1.04). The odds ratio of CHD for a 1 SD genetically elevated serum total bilirubin level was 1.03 (95% confidence interval, 0.98 to 1.09). The current findings casts doubt on a strong causal association of serum total bilirubin levels with CHD. The inverse associations demonstrated in observational studies may be driven by biases such as unmeasured confounding and/or reverse causation. However, further research in large-scale consortia is needed. Copyright © 2015 Elsevier Inc. All rights reserved.

Age-dependent pattern of cerebellar susceptibility to bilirubin neurotoxicity in vivo in mice

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Bortolussi, Giulia; Baj, Gabriele; Vodret, Simone; Viviani, Giulia; Bittolo, Tamara; Muro, Andrés F.

2014-01-01

Neonatal jaundice is caused by high levels of unconjugated bilirubin. It is usually a temporary condition caused by delayed induction of UGT1A1, which conjugates bilirubin in the liver. To reduce bilirubin levels, affected babies are exposed to phototherapy (PT), which converts toxic bilirubin into water-soluble photoisomers that are readily excreted out. However, in some cases uncontrolled hyperbilirubinemia leads to neurotoxicity. To study the mechanisms of bilirubin-induced neurological damage (BIND) in vivo, we generated a mouse model lacking the Ugt1a1 protein and, consequently, mutant mice developed jaundice as early as 36 hours after birth. The mutation was transferred into two genetic backgrounds (C57BL/6 and FVB/NJ). We exposed mutant mice to PT for different periods and analyzed the resulting phenotypes from the molecular, histological and behavioral points of view. Severity of BIND was associated with genetic background, with 50% survival of C57BL/6‑Ugt1−/− mutant mice at postnatal day 5 (P5), and of FVB/NJ-Ugt1−/− mice at P11. Life-long exposure to PT prevented cerebellar architecture alterations and rescued neuronal damage in FVB/NJ-Ugt1−/− but not in C57BL/6-Ugt1−/− mice. Survival of FVB/NJ-Ugt1−/− mice was directly related to the extent of PT treatment. PT treatment of FVB/NJ-Ugt1−/− mice from P0 to P8 did not prevent bilirubin-induced reduction in dendritic arborization and spine density of Purkinje cells. Moreover, PT treatment from P8 to P20 did not rescue BIND accumulated up to P8. However, PT treatment administered in the time-window P0–P15 was sufficient to obtain full rescue of cerebellar damage and motor impairment in FVB/NJ-Ugt1−/− mice. The possibility to modulate the severity of the phenotype by PT makes FVB/NJ-Ugt1−/− mice an excellent and versatile model to study bilirubin neurotoxicity, the role of modifier genes, alternative therapies and cerebellar development during high bilirubin conditions. PMID

Bilirubin and atherosclerotic diseases.

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Vítek, L

2017-04-05

Bilirubin is the final product of heme catabolism in the systemic circulation. For decades, increased serum/plasma bilirubin levels were considered an ominous sign of an underlying liver disease. However, data from recent years convincingly suggest that mildly elevated bilirubin concentrations are associated with protection against various oxidative stress-mediated diseases, atherosclerotic conditions being the most clinically relevant. Although scarce data on beneficial effects of bilirubin had been published also in the past, it took until 1994 when the first clinical study demonstrated an increased risk of coronary heart disease in subjects with low serum bilirubin levels, and bilirubin was found to be a risk factor for atherosclerotic diseases independent of standard risk factors. Consistent with these results, we proved in our own studies, that subjects with mild elevation of serum levels of unconjugated bilirubin (benign hyperbilirubinemia, Gilbert syndrome) have much lower prevalence/incidence of coronary heart as well as peripheral vascular disease. We have also demonstrated that this association is even more general, with serum bilirubin being a biomarker of numerous other diseases, often associated with increased risk of atherosclerosis. In addition, very recent data have demonstrated biological pathways modulated by bilirubin, which are responsible for observed strong clinical associations.

Bilirubin-albumin binding, bilirubin/albumin ratios, and free bilirubin levels : Where do we stand?

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Hulzebos, Christian V.; Dijk, Peter H.

2014-01-01

Treatment for unconjugated hyperbilirubinemia is predominantly based on one parameter, i.e., total serum bilirubin (TSB) levels. Yet, overt kernicterus has been reported in preterm infants at relatively low TSB levels, and it has been repeatedly shown that free unconjugated bilirubin (freeUCB)

Validation of a transcutaneous bilirubin meter in Mongolian neonates: comparison with total serum bilirubin.

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Akahira-Azuma, Moe; Yonemoto, Naohiro; Ganzorig, Battsengel; Mori, Rintaro; Hosokawa, Shinichi; Matsushita, Takeji; Bavuusuren, Bayasgalantai; Shonkhuuz, Enkhtur

2013-09-27

Neonatal hyperbilirubinemia, especially kernicterus, can be prevented by screening for neonatal jaundice. The transcutaneous bilirubin (TcB) meter is a non-invasive medical device for screening neonates. The study aimed to investigate the validity of a TcB meter in a resource-limited setting such as Mongolia. Term and late preterm neonates from the National Center for Maternal and Child Health of Ulaanbaatar in Mongolia who met the inclusion criteria (gestational age ≥35 weeks, birth weight ≥2000 g, postnatal age ≤ 1 month) were enrolled in the study. We used a TcB meter, JM-103 to screen for neonatal jaundice. TcB measurements at the infant's forehead and midsternum were performed within 3 h of obtaining samples for total serum bilirubin (TSB) measurement. We analyzed the correlation between TcB measurements and TSB measurements to validate the meter. A total of 47 term and six late preterm neonates were included in the study. TcB measured by the meter at both the forehead and the midsternum showed a strong correlation with TSB measured in the laboratory. The correlation equations were TSB = 1.409+0.8655 × TcB (R2=0.78871) at the forehead, and TSB = 0.7555+0.8974 × TcB (R2=0.78488) at the midsternum. Bland-Altman plots and the Bradley-Blackwood test showed no significant differences between the two methods at all measured ranges of bilirubin. The mean areas under the curves of TcB at the forehead and midsternum at three TSB levels (>10 mg/dL, >13 mg/dL, >15 mg/dL) of TcB were greater than 0.9, and all had high sensitivity and specificity. This study established the validity of the JM-103 meter as a screening tool for neonatal jaundice in term and late preterm infants in Mongolia. Future studies are needed, including the establishment of a TcB hour-specific nomogram, for more effective clinical practice to prevent severe hyperbilirubinemia.

Percutaneous biliary drainage effectively lowers serum bilirubin to permit chemotherapy treatment.

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Levy, Jennifer L; Sudheendra, Deepak; Dagli, Mandeep; Mondschein, Jeffrey I; Stavropoulos, S William; Shlansky-Goldberg, Richard D; Trerotola, Scott O; Teitelbaum, Ursina; Mick, Rosemarie; Soulen, Michael C

2016-02-01

For digestive tract cancers, the bilirubin threshold for administration of systemic chemotherapy can be 5 or 2 mg/dL (85.5 or 34.2 μmol/L) depending upon the regimen. We examined the ability of percutaneous biliary drainage (PBD) in patients with malignant biliary obstruction to achieve these clinically relevant endpoints. 106 consecutive patients with malignant biliary obstruction and a baseline serum bilirubin >2 mg/dL underwent PBD. Time to achieve a bilirubin of 5 mg/dL (85.5 μmol/L), 2 mg/dL (34.2 μmol/L), and survival was estimated by Kaplan-Meier analysis. Potential technical and clinical prognostic factors were subjected to univariate and multivariate analysis. Categorical variables were analyzed by the log rank test. Hazard ratios were calculated for continuous variables. Median survival was 100 days (range 1-3771 days). Among 88 patients with a pre-drainage bilirubin >5 mg/dL, 62% achieved a serum bilirubin ≤5 mg/dL within 30 days and 84% within 60 days, median 21 days. Among 106 patients with a pre-drainage bilirubin >2 mg/dL, 37% achieved a serum bilirubin ≤2 mg/dL by 30 days and 70% within 60 days, median 43 days. None of the technical or clinical factors evaluated, including pre-drainage bilirubin, were significant predictors of time to achieve a bilirubin ≤2 mg/dL (p = 0.51). Size and type of biliary device were the only technical variables found to affect time to bilirubin of 5 mg/dL (p = 0.016). PBD of malignant obstruction achieves clinically relevant reduction in serum bilirubin in the majority of patients within 1-2 months, irrespective of the pre-drainage serum bilirubin, sufficient to allow administration of systemic chemotherapy. However, the decision to undergo this procedure for this indication alone must be considered in the context of patients' prognosis and treatment goals.

Crystal structure of product-bound complex of UDP-N-acetyl-D-mannosamine dehydrogenase from Pyrococcus horikoshii OT3

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Pampa, K.J., E-mail: sagarikakj@gmail.com [Department of Studies in Microbiology, University of Mysore, Mysore 570 006 (India); Lokanath, N.K. [Department of Studies in Physics, University of Mysore, Mysore 570 006 (India); Girish, T.U. [Department of General Surgery, JSS Medical College and Hospital, JSS University, Mysore 570 015 (India); Kunishima, N. [Advanced Protein Crystallography Research Group, RIKEN SPring-8 Center, Harima Institute, Hyogo 679-5148 (Japan); Rai, V.R. [Department of Studies in Microbiology, University of Mysore, Mysore 570 006 (India)

2014-10-24

Highlights: • Determined the structure of UDP-D-ManNAcADH to a resolution of 1.55 Å. • First complex structure of PhUDP-D-ManNAcADH with UDP-D-ManMAcA. • The monomeric structure consists of three distinct domains. • Cys258 acting as catalytic nucleophilic and Lys204 acts as acid/base catalyst. • Oligomeric state plays an important role for the catalytic function. - Abstract: UDP-N-acetyl-D-mannosamine dehydrogenase (UDP-D-ManNAcDH) belongs to UDP-glucose/GDP-mannose dehydrogenase family and catalyzes Uridine-diphospho-N-acetyl-D-mannosamine (UDP-D-ManNAc) to Uridine-diphospho-N-acetyl-D-mannosaminuronic acid (UDP-D-ManNAcA) through twofold oxidation of NAD{sup +}. In order to reveal the structural features of the Pyrococcus horikoshii UDP-D-ManNAcADH, we have determined the crystal structure of the product-bound enzyme by X-ray diffraction to resolution of 1.55 Å. The protomer folds into three distinct domains; nucleotide binding domain (NBD), substrate binding domain (SBD) and oligomerization domain (OD, involved in the dimerization). The clear electron density of the UDP-D-ManNAcA is observed and the residues binding are identified for the first time. Crystal structures reveal a tight dimeric polymer chains with product-bound in all the structures. The catalytic residues Cys258 and Lys204 are conserved. The Cys258 acts as catalytic nucleophile and Lys204 as acid/base catalyst. The product is directly interacts with residues Arg211, Thr249, Arg244, Gly255, Arg289, Lys319 and Arg398. In addition, the structural parameters responsible for thermostability and oligomerization of the three dimensional structure are analyzed.

Essential Roles of Raf/Extracellular Signal-regulated Kinase/Mitogen-activated Protein Kinase Pathway, YY1, and Ca2+ Influx in Growth Arrest of Human Vascular Smooth Muscle Cells by Bilirubin*

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Stoeckius, Marlon; Erat, Anna; Fujikawa, Tatsuya; Hiromura, Makoto; Koulova, Anna; Otterbein, Leo; Bianchi, Cesario; Tobiasch, Edda; Dagon, Yossi; Sellke, Frank W.; Usheva, Anny

2012-01-01

The biological effects of bilirubin, still poorly understood, are concentration-dependent ranging from cell protection to toxicity. Here we present data that at high nontoxic physiological concentrations, bilirubin inhibits growth of proliferating human coronary artery smooth muscle cells by three events. It impairs the activation of Raf/ERK/MAPK pathway and the cellular Raf and cyclin D1 content that results in retinoblastoma protein hypophosphorylation on amino acids S608 and S780. These events impede the release of YY1 to the nuclei and its availability to regulate the expression of genes and to support cellular proliferation. Moreover, altered calcium influx and calpain II protease activation leads to proteolytical degradation of transcription factor YY1. We conclude that in the serum-stimulated human vascular smooth muscle primary cell cultures, bilirubin favors growth arrest, and we propose that this activity is regulated by its interaction with the Raf/ERK/MAPK pathway, effect on cyclin D1 and Raf content, altered retinoblastoma protein profile of hypophosphorylation, calcium influx, and YY1 proteolysis. We propose that these activities together culminate in diminished 5 S and 45 S ribosomal RNA synthesis and cell growth arrest. The observations provide important mechanistic insight into the molecular mechanisms underlying the transition of human vascular smooth muscle cells from proliferative to contractile phenotype and the role of bilirubin in this transition. PMID:22262839

Cloning, expression, purification, crystallization and preliminary crystallographic studies of UgdG, an UDP-glucose dehydrogenase from Sphingomonas elodea ATCC 31461

International Nuclear Information System (INIS)

Rocha, Joana; Granja, Ana Teresa; Sá-Correia, Isabel; Fialho, Arsénio; Frazão, Carlos

2009-01-01

Crystals of S. elodea ATCC 31461 UDP-glucose dehydrogenase (EC 1.1.1.22) were obtained in space groups P622 and P4 3 2 1 2 and diffracted to 2.4 and 3.4 Å resolution, respectively. Gellan gum, a commercial gelling agent produced by Sphingomonas elodea ATCC 31461, is a high-value microbial exopolysaccharide. UDP-glucose dehydrogenase (UGD; EC 1.1.1.22) is responsible for the NAD-dependent twofold oxidation of UDP-glucose to UDP-glucuronic acid, one of the key components for gellan biosynthesis. S. elodea ATCC 31461 UGD, termed UgdG, was cloned, expressed, purified and crystallized in native and SeMet-derivatized forms in hexagonal and tetragonal space groups, respectively; the crystals diffracted X-rays to 2.40 and 3.40 Å resolution, respectively. Experimental phases were obtained for the tetragonal SeMet-derivatized crystal form by a single-wavelength anomalous dispersion experiment. This structure was successfully used as a molecular-replacement probe for the hexagonal crystal form of the native protein

Enhanced thyroid hormone breakdown in hepatocytes by mutual induction of the constitutive androstane receptor (CAR, NR1I3) and arylhydrocarbon receptor by benzo[a]pyrene and phenobarbital

International Nuclear Information System (INIS)

Schraplau, Anne; Schewe, Bettina; Neuschäfer-Rube, Frank; Ringel, Sebastian; Neuber, Corinna; Kleuser, Burkhard; Püschel, Gerhard P.

2015-01-01

Xenobiotics may interfere with the hypothalamic-pituitary-thyroid endocrine axis by inducing enzymes that inactivate thyroid hormones and thereby reduce the metabolic rate. This induction results from an activation of xeno-sensing nuclear receptors. The current study shows that benzo[a]pyrene, a frequent contaminant of processed food and activator of the arylhydrocarbon receptor (AhR) activated the promoter and induced the transcription of the nuclear receptor constitutive androstane receptor (CAR, NR1I3) in rat hepatocytes. Likewise, phenobarbital induced the AhR transcription. This mutual induction of the nuclear receptors enhanced the phenobarbital-dependent induction of the prototypic CAR target gene Cyp2b1 as well as the AhR-dependent induction of UDP-glucuronosyltransferases. In both cases, the induction by the combination of both xenobiotics was more than the sum of the induction by either substance alone. By inducing the AhR, phenobarbital enhanced the benzo[a]pyrene-dependent reduction of thyroid hormone half-life and the benzo[a]pyrene-dependent increase in the rate of thyroid hormone glucuronide formation in hepatocyte cultures. CAR ligands might thus augment the endocrine disrupting potential of AhR activators by an induction of the AhR

Genetic variations and haplotype diversity of the UGT1 gene cluster in the Chinese population.

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Jing Yang

Full Text Available Vertebrates require tremendous molecular diversity to defend against numerous small hydrophobic chemicals. UDP-glucuronosyltransferases (UGTs are a large family of detoxification enzymes that glucuronidate xenobiotics and endobiotics, facilitating their excretion from the body. The UGT1 gene cluster contains a tandem array of variable first exons, each preceded by a specific promoter, and a common set of downstream constant exons, similar to the genomic organization of the protocadherin (Pcdh, immunoglobulin, and T-cell receptor gene clusters. To assist pharmacogenomics studies in Chinese, we sequenced nine first exons, promoter and intronic regions, and five common exons of the UGT1 gene cluster in a population sample of 253 unrelated Chinese individuals. We identified 101 polymorphisms and found 15 novel SNPs. We then computed allele frequencies for each polymorphism and reconstructed their linkage disequilibrium (LD map. The UGT1 cluster can be divided into five linkage blocks: Block 9 (UGT1A9, Block 9/7/6 (UGT1A9, UGT1A7, and UGT1A6, Block 5 (UGT1A5, Block 4/3 (UGT1A4 and UGT1A3, and Block 3' UTR. Furthermore, we inferred haplotypes and selected their tagSNPs. Finally, comparing our data with those of three other populations of the HapMap project revealed ethnic specificity of the UGT1 genetic diversity in Chinese. These findings have important implications for future molecular genetic studies of the UGT1 gene cluster as well as for personalized medical therapies in Chinese.

Purification, crystallization and preliminary X-ray diffraction studies of UDP-N-acetylglucosamine pyrophosphorylase from Candida albicans

Energy Technology Data Exchange (ETDEWEB)

Maruyama, Daisuke; Nishitani, Yuichi; Nonaka, Tsuyoshi; Kita, Akiko [Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan); Fukami, Takaaki A.; Mio, Toshiyuki; Yamada-Okabe, Hisafumi [Kamakura Research Laboratory, Chugai Pharmaceutical Co. Ltd, 200 Kajiwara, Kamakura, Kanagawa 247-8530 (Japan); Yamada-Okabe, Toshiko [Department of Hygiene, School of Medicine, Yokohama City University, 3-9 Fukuura, Kanazawa, Yokohama 236-0004 (Japan); Miki, Kunio, E-mail: miki@kuchem.kyoto-u.ac.jp [Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan); RIKEN SPring-8 Center at Harima Institute, Koto 1-1-1, Sayocho, Sayo-gun, Hyogo 679-5148 (Japan)

2006-12-01

UDP-N-acetylglucosamine pyrophosphorylase was purified and crystallized and X-ray diffraction data were collected to 2.3 Å resolution. UDP-N-acetylglucosamine pyrophosphorylase (UAP) is an essential enzyme in the synthesis of UDP-N-acetylglucosamine. UAP from Candida albicans was purified and crystallized by the sitting-drop vapour-diffusion method. The crystals of the substrate and product complexes both diffract X-rays to beyond 2.3 Å resolution using synchrotron radiation. The crystals of the substrate complex belong to the triclinic space group P1, with unit-cell parameters a = 47.77, b = 62.89, c = 90.60 Å, α = 90.01, β = 97.72, γ = 92.88°, whereas those of the product complex belong to the orthorhombic space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 61.95, b = 90.87, c = 94.88 Å.

Differences in UGT1A1, UGT1A7, and UGT1A9 polymorphisms between Uzbek and Japanese populations.

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Maeda, Hiromichi; Hazama, Shoichi; Shavkat, Abdiev; Okamoto, Ken; Oba, Koji; Sakamoto, Junichi; Takahashi, Kenichi; Oka, Masaki; Nakamura, Daisuke; Tsunedomi, Ryouichi; Okayama, Naoko; Mishima, Hideyuki; Kobayashi, Michiya

2014-06-01

Uridine-diphosphate glucuronosyltransferase 1A (UGT1A) is a key enzyme involved in irinotecan metabolism, and polymorphisms in the UGT1A gene are associated with irinotecan-induced toxicity. The aim of this study was to elucidate the allele frequencies of UGT1A polymorphisms in healthy Uzbek volunteers, and to compare them with those of the Japanese population. A total of 97 healthy volunteers from Uzbekistan were enrolled and blood samples were collected from each participant. Genotyping analysis was performed by fragment size analysis for UGT1A1*28, direct sequencing for UGT1A7*3 and UGT1A9*22, and TaqMan assays for UGT1A1*93, UGT1A1*6, UGT1A1*27, UGT1A1*60, and UGT1A7*12. The frequencies of polymorphisms were compared with the Japanese population by using the data previously reported from our study group. When the Uzbek and Japanese populations were compared, heterozygotes or homozygotes for UGT1A1*28, UGT1A1*60, and UGT1A1*93 were significantly more frequent in the Uzbek population (P Japanese population (P Japanese population. A comprehensive study of the influence of UGT1A1 polymorphisms on the risk of irinotecan-induced toxicity is necessary for optimal use of irinotecan treatment.

Imbalance between production and conjugation of bilirubin: a fundamental concept in the mechanism of neonatal jaundice.

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Kaplan, Michael; Muraca, Maurizio; Hammerman, Cathy; Rubaltelli, Firmino F; Vilei, Maria T; Vreman, Hendrik J; Stevenson, David K

2002-10-01

The objective of this study was to evaluate the roles of production and conjugation of bilirubin, individually and in combination, in the mechanism of neonatal jaundice. A cohort of healthy, term male newborns was sampled on the third day of life, coincident with routine metabolic screening, for blood carboxyhemoglobin determination, a reflection of heme catabolism, and for serum unconjugated and conjugated bilirubin fractions, reflecting bilirubin conjugation. The former was determined by gas chromatography, corrected for inspired CO (COHbc), and expressed as percentage of total hemoglobin. Serum bilirubin fractions were quantified by alkaline methanolysis and reverse phase high performance liquid chromatography. The sum of all bilirubin fractions comprised serum total bilirubin (STB). Total conjugated bilirubin (TCB) was comprised of the sum of the conjugated fractions and was expressed as percentage of STB (TCB[%]). A "bilirubin production/conjugation index" (COHbc/[TCB(%)] represented the combined roles of these modalities in the mechanism of bilirubinemia. Relationships between STB concentrations on the one hand, and COHbc values, TCB(%) proportions, and the production/conjugation index on the other, were determined by applying a best-fit regression analysis methodology. Mean (+/- standard deviation) STB concentration at the time of sampling was 114 +/- 48 micro mol/L (range: 8-263 micro mol/L). Mean COHbc value was 0.77 +/- 0.19%, and median (interquartile range) TCB(%) was 0.737 (0.465-1.260)%. COHbc values correlated directly with STB concentrations (r = 0.38; s = 46.1), and TCB(%) correlated inversely with STB (r = 0.40; s = 45.8). The production/conjugation index correlated positively with STB values (r = 0.61; s = 45.8), the r value for the index being higher than that of either COHbc or TCB(%), individually. The bilirubin production/conjugation index seemed to have a biphasic relationship to STB: STB values rose steeply in concert with increasing index

Bilirubin and Stroke Risk Using a Mendelian Randomization Design.

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Lee, Sun Ju; Jee, Yon Ho; Jung, Keum Ji; Hong, Seri; Shin, Eun Soon; Jee, Sun Ha

2017-05-01

Circulating bilirubin, a natural antioxidant, is associated with decreased risk of stroke. However, the nature of the relationship between the two remains unknown. We used a Mendelian randomization analysis to assess the causal effect of serum bilirubin on stroke risk in Koreans. The 14 single-nucleotide polymorphisms (SNPs) (bilirubin level in the KCPS-II (Korean Cancer Prevention Study-II) Biobank subcohort consisting of 4793 healthy Korean and 806 stroke cases. Weighted genetic risk score was calculated using 14 SNPs selected from the top SNPs. Both rs6742078 (F statistics=138) and weighted genetic risk score with 14 SNPs (F statistics=187) were strongly associated with bilirubin levels. Simultaneously, serum bilirubin level was associated with decreased risk of stroke in an ordinary least-squares analysis. However, in 2-stage least-squares Mendelian randomization analysis, no causal relationship between serum bilirubin and stroke risk was found. There is no evidence that bilirubin level is causally associated with risk of stroke in Koreans. Therefore, bilirubin level is not a risk determinant of stroke. © 2017 American Heart Association, Inc.

The Relation of Serum Bilirubin Level With Coronary Artery Disease Based on Angiographic Findings

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Taban Sadeghi Mohammadreza

2015-10-01

Full Text Available Objective: Lipid oxidation and generation of free radicals are important factors contributing to the formation of atherosclerotic plaque. Bilirubin is supposed to play a protective role against atherosclerosis, coronary artery diseases (CAD and inflammation for its strong antioxidant property. Thus, this study aims at investigating the relationship of bilirubin level with the severity and type of coronary artery stenosis (CAS in different patient groups. Materials and Methods: In this cross-sectional study 200 consecutive patients, who underwent elective angiography in Madani Heart hospital, Tabriz, Iran, were selected and their blood samples were measured for total, direct, and indirect bilirubin level, with Diazo method using colorimetric technique. Following angiography, comparisons were made between the severity and location of CAS and therapeutic follow-up plan with total, direct, and indirect bilirubin level. Results: Of 200 studied patients, 129 (64.5% and 71 (35.5% subjects were male and female, respectively. The cases were classified into 5 subgroups based on angiography results as follows: 59 (29.5% cases with normal angiography, 11 cases (5.5% with minimal CAD, 56 cases (28% with single vessel involvement, 35 (17.5% cases with two vessel involvement and 39 cases (19.5% with three vessel involvement. The mean total bilirubin level was 1.47 ± 0.8 mg/dl, 1.27 ± 0.12 mg/dl, 1.27 ± 0.06 mg/dl, 1.6 ± 0.04 mg/dl and 0.98 ± 0.05 mg/dl, respectively for the cases with above order. The mean difference in serum total bilirubin between normal angiography group and three-vessel involvement group was 0.49 mg/dl (P < .0001. There was a significant inverse relation between bilirubin level (total, direct and indirect and number of involved vessels and involvement intensity increased as serum bilirubin level decreased. Severity of coronary arteries stenosis as well as the number of involved vessels increased as serum bilirubin level decreased

The Biological Effects of Bilirubin Photoisomers

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Jasprova, Jana; Dal Ben, Matteo; Vianello, Eleonora; Goncharova, Iryna; Urbanova, Marie; Vyroubalova, Karolina; Gazzin, Silvia; Tiribelli, Claudio; Sticha, Martin; Cerna, Marcela; Vitek, Libor

2016-01-01

Although phototherapy was introduced as early as 1950’s, the potential biological effects of bilirubin photoisomers (PI) generated during phototherapy remain unclear. The aim of our study was to isolate bilirubin PI in their pure forms and to assess their biological effects in vitro. The three major bilirubin PI (ZE- and EZ-bilirubin and Z-lumirubin) were prepared by photo-irradiation of unconjugated bilirubin. The individual photoproducts were chromatographically separated (TLC, HPLC), and their identities verified by mass spectrometry. The role of Z-lumirubin (the principle bilirubin PI) on the dissociation of bilirubin from albumin was tested by several methods: peroxidase, fluorescence quenching, and circular dichroism. The biological effects of major bilirubin PI (cell viability, expression of selected genes, cell cycle progression) were tested on the SH-SY5Y human neuroblastoma cell line. Lumirubin was found to have a binding site on human serum albumin, in the subdomain IB (or at a close distance to it); and thus, different from that of bilirubin. Its binding constant to albumin was much lower when compared with bilirubin, and lumirubin did not affect the level of unbound bilirubin (Bf). Compared to unconjugated bilirubin, bilirubin PI did not have any effect on either SH-SY5Y cell viability, the expression of genes involved in bilirubin metabolism or cell cycle progression, nor in modulation of the cell cycle phase. The principle bilirubin PI do not interfere with bilirubin albumin binding, and do not exert any toxic effect on human neuroblastoma cells. PMID:26829016

Prevalence of Bilirubin Encephalopathy in Calabar, South-South Nigeria: A Five-year Review Study

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Sunny Oteikwu Ochigbo

2016-03-01

Full Text Available Background: Bilirubin encephalopathy is a clinical syndrome, associated with bilirubin toxicity in the central nervous system, resulting in chronic and permanent sequelae. It has been estimated that approximately 60% and 80% of term and preterm newborns develop jaundice in the first week of life, respectively. In the present study, we aimed to determine the prevalence, morbidity, and mortality of bilirubin encephalopathy in the neonatal unit of the University of Calabar Teaching Hospital, Calabar, Nigeria. Methods: In this retrospective, descriptive review, medical records of all newborns, diagnosed with bilirubin encephalopathy over the past five years (from January 2010 to December 2014, were studied. Information retrieved from the medical records included age, sex, presence of fever, duration of disease, place of delivery, causes of the disease, and selected treatments. Variables such as hospital discharge, discharge against medical advice, and mortality were also evaluated. Results: Out of 2,820 newborns, 21 (0.74% cases were admitted on account of bilirubin encephalopathy. Among these affected cases, 17 (81% were male and 4 (19% were female (male-to-female ratio of 5:1. Based on the findings, 18 newborns (85.7% had pyrexia, while 8 (38.1% and 6 (28.6% cases were hypertonic and hypotonic, respectively upon admission. Only 33.3% of deliveries took place in healthcare facilities. The established factors responsible for jaundice included infection, i.e., septicemia (n=15, 71.4%, ABO incompatibility (n=4, 19.1%, and glucose-6-phosphate-dehydrogenase (G6PD deficiency (n=2, 9.5%. The mean maximum total bilirubin level in subjects was 321.3 μmol/L (range: 242.5–440.3 μmol/L. Also, mortality was reported in 4 (19% out of 21 cases. Conclusion: Based on the findings, neonatal septicemia is associated with bilirubin encephalopathy. Therefore, identification and prompt treatment are of utmost importance in preventing the associated morbidity and

Bilirubin modulated cytokines, growth factors and angiogenesis to improve cutaneous wound healing process in diabetic rats.

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Ram, Mahendra; Singh, Vishakha; Kumawat, Sanjay; Kant, Vinay; Tandan, Surendra Kumar; Kumar, Dinesh

2016-01-01

Bilirubin has shown cutaneous wound healing potential in some preliminary studies. Here we hypothesize that bilirubin facilitates wound healing in diabetic rats by modulating important healing factors/candidates and antioxidant parameters in a time-dependent manner. Diabetes was induced in male Wistar rats by streptozotocin. In all diabetic rats wounds were created under pentobarbitone anesthesia. All the rats were divided into two groups, of which one (control) was treated with ointment base and other with bilirubin ointment (0.3%). Wound closer measurement and tissue collection were done on days 3, 7, 14 and 19 post-wounding. The relative expressions of hypoxia inducible factor-1 alpha (HIF-1α), vascular endothelial growth factor (VEGF), stromal cell-derived factor-1 alpha (SDF-1α), transforming growth factor- beta1 (TGF-β1()), tumor necrosis factor-α (TNF-α) and interlukin-10 (IL-10) mRNA and proteins and the mRNA of interlukin-1 beta (IL-1β) and matrix metalloprteinase-9 (MMP-9) were determined in the wound tissues. CD-31 staining and collagen content were evaluated by immunohistochemistry and picrosirius red staining, respectively. Histopathological changes were assessed by H&E staining. The per cent wound closer was significantly higher from day 7 onwards in bilirubin-treated rats. HIF-1α, VEGF, SDF-1α, TGF-β1, IL-10 mRNA and protein levels were significantly higher on days 3, 7 and 14 in bilirubin-treated rats. The mRNA expression and protein level of TNF-α and the mRNA of IL-1β and MMP-9 were progressively and markedly reduced in bilirubin-treated rats. The collagen deposition and formation of blood vessels were greater in bilirubin-treated rats. Bilirubin markedly facilitated cutaneous wound healing in diabetic rats by modulating growth factors, cytokines, neovasculogenesis and collagen contents to the wound site. Topical application of bilirubin ointment might be of great use in cutaneous wound healing in diabetic patients. Copyright © 2015

Surface-modified anodic aluminum oxide membrane with hydroxyethyl celluloses as a matrix for bilirubin removal.

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Xue, Maoqiang; Ling, Yisheng; Wu, Guisen; Liu, Xin; Ge, Dongtao; Shi, Wei

2013-01-01

Microporous anodic aluminum oxide (AAO) membranes were modified by 3-glycidoxypropyltrimethoxysilane to produce terminal epoxy groups. These were used to covalently link hydroxyethyl celluloses (HEC) to amplify reactive groups of AAO membrane. The hydroxyl groups of HEC-AAO composite membrane were further modified with 1,4-butanediol diglycidyl ether to link arginine as an affinity ligand. The contents of HEC and arginine of arginine-immobilized HEC-AAO membrane were 52.1 and 19.7mg/g membrane, respectively. As biomedical adsorbents, the arginine-immobilized HEC-AAO membranes were tested for bilirubin removal. The non-specific bilirubin adsorption on the unmodified HEC-AAO composite membranes was 0.8mg/g membrane. Higher bilirubin adsorption values, up to 52.6mg/g membrane, were obtained with the arginine-immobilized HEC-AAO membranes. Elution of bilirubin showed desorption ratio was up to 85% using 0.3M NaSCN solution as the desorption agent. Comparisons equilibrium and dynamic capacities showed that dynamic capacities were lower than the equilibrium capacities. In addition, the adsorption mechanism of bilirubin and the effects of temperature, initial concentration of bilirubin, albumin concentration and ionic strength on adsorption were also investigated. Copyright © 2012 Elsevier B.V. All rights reserved.

Physiologic Doses of Bilirubin Contribute to Tolerance of Islet Transplants by Suppressing the Innate Immune Response.

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Adin, Christopher A; VanGundy, Zachary C; Papenfuss, Tracey L; Xu, Feng; Ghanem, Mostafa; Lakey, Jonathan; Hadley, Gregg A

2017-01-24

Bilirubin has been recognized as a powerful cytoprotectant when used at physiologic doses and was recently shown to have immunomodulatory effects in islet allograft transplantation, conveying donor-specific tolerance in a murine model. We hypothesized that bilirubin, an antioxidant, acts to suppress the innate immune response to islet allografts through two mechanisms: 1) by suppressing graft release of damage-associated molecular patterns (DAMPs) and inflammatory cytokines, and 2) by producing a tolerogenic phenotype in antigen-presenting cells. Bilirubin was administered intraperitoneally before pancreatic procurement or was added to culture media after islet isolation in AJ mice. Islets were exposed to transplant-associated nutrient deprivation and hypoxia. Bilirubin significantly decreased islet cell death after isolation and hypoxic stress. Bilirubin supplementation of islet media also decreased the release of DAMPs (HMGB1), inflammatory cytokines (IL-1β and IL-6), and chemokines (MCP-1). Cytoprotection was mediated by the antioxidant effects of bilirubin. Treatment of macrophages with bilirubin induced a regulatory phenotype, with increased expression of PD-L1. Coculture of these macrophages with splenocytes led to expansion of Foxp3+ Tregs. In conclusion, exogenous bilirubin supplementation showed cytoprotective and antioxidant effects in a relevant model of islet isolation and hypoxic stress. Suppression of DAMP release, alterations in cytokine profiles, and tolerogenic effects on macrophages suggest that the use of this natural antioxidant may provide a method of preconditioning to improve outcomes after allograft transplantation.

Serum bilirubin levels are positively associated with glycemic variability in women with type 2 diabetes.

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Kim, Lee Kyung; Roh, Eun; Kim, Min Joo; Kim, Min Kyeong; Park, Kyeong Seon; Kwak, Soo Heon; Cho, Young Min; Park, Kyong Soo; Jang, Hak Chul; Jung, Hye Seung

2016-11-01

Glycemic variability is known to induce oxidative stress. We investigated the relationships between glycemic variability and serum bilirubin levels, an endogenous anti-oxidant, in patients with diabetes. A cross-sectional study was carried out with 77 patients with type 2 diabetes who had been recruited to two clinical studies from 2008 to 2014. There were no participants with diseases of the pancreas, liver, biliary tract and chronic renal insufficiency. Glycemic variation was calculated by a continuous glucose monitoring system, and correlation analyses were carried out to evaluate their association with bilirubin levels. Multiple linear regression was carried out to identify independent factors influencing bilirubin levels and glycemic variation. Among the participants, 42.3% were men. The mean (standard deviation) age was 61.5 years (10.4 years), body mass index was 24.2 kg/m 2 (2.8 kg/m 2 ), diabetes duration was 17.7 years (9.5 years), hemoglobin A 1c was 60.7 mmol/mol (7.1 mmol/mol; 7.7 [0.7]%) and bilirubin was 11.8 μmol/L (4.10 μmol/L). Serum bilirubin levels were not different according to age, body mass index and hemoglobin A 1c . However, the mean amplitude of glucose excursion was positively associated with bilirubin levels in women (r = 0.588, P bilirubin and mean amplitude of glucose excursion remained significant (r = 0.566, P bilirubin was an independent determinant for the mean amplitude of glucose excursion in women. 1,5-Anhydroglucitol was also associated with bilirubin levels in women. Bilirubin level within the physiological range might be an independent predictor for glycemic variability in women with type 2 diabetes. © 2016 The Authors. Journal of Diabetes Investigation published by Asian Association for the Study of Diabetes (AASD) and John Wiley & Sons Australia, Ltd.

Tissue and species differences in the glucuronidation of glabridin with UDP-glucuronosyltransferases.

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Guo, Bin; Fang, Zhongze; Yang, Lu; Xiao, Ling; Xia, Yangliu; Gonzalez, Frank J; Zhu, Liangliang; Cao, Yunfeng; Ge, Guangbo; Yang, Ling; Sun, Hongzhi

2015-04-25

Glabridin (GA) has gained wide application in the cosmetics and food industry. This study was performed to investigate its metabolic inactivation and elimination by glucuronidation by use of liver and intestine microsomes from humans (HLM and HIM) and rats (RLM and RIM), and liver microsomes from cynomolgus monkeys and beagle dogs (CyLM and DLM). Both hydroxyl groups at the C2 and C4 positions of the B ring are conjugated to generate two mono-glucuronides (M1 and M2). HIM, RIM and RLM showed the most robust activity in catalyzing M2 formation with intrinsic clearance values (Clint) above 2000 μL/min/mg, with little measurable M1 formation activity. DLM displayed considerable activity both in M1 and M2 formation, with Clint values of 71 and 214 μL/min/mg, respectively, while HLM and CyLM exhibited low activities in catalyzing M1 and M2 formation, with Clint values all below 20 μL/min/mg. It is revealed that UGT1A1, 1A3, 1A9, 2B7, 2B15 and extrahepatic UGT1A8 and 1A10 are involved in GA glucuronidation. Nearly all UGTs preferred M2 formation except for UGT1A1. Notably, UGT1A8 displayed the highest activity with a Clint value more than 5-fold higher than the other isoforms. Chemical inhibition studies, using selective inhibitors of UGT1A1, 1A9, 2B7 and 1A8, further revealed that UGT1A8 contributed significantly to intestinal GA glucuronidation in humans. In summary, this in vitro study demonstrated large species differences in GA glucuronidation by liver and intestinal microsomes, and that intestinal UGTs are important for the pathway in humans. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

CHARACTERIZATION OF HUMAN LIVER MICROSOMAL UDP-GLYCOSYLTRANSFERASES USING PHOTOAFFINITY ANALOGS

NARCIS (Netherlands)

LITTLE, JM; DRAKE, RR; VONK, R; KUIPERS, F; LESTER, R; RADOMINSKA, A

The photoaffinity analogs [beta-P-32]5-azido-UDP-glucuronic acid ([P-32]5N3UDP-GlcUA) and [beta-P-32]5-azido-UDP-glucose ([P-32]5N(3)UDP-Glc) were used to characterize UDP-glycosyl-transferases of microsomes prepared from human liver. Photoincorporation of both probes into proteins in the 50- to

Early predictive value of cord blood bilirubin and dynamic monitoring of transcutaneous bilirubin for hyperbilirubinemia of newborns

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Haishan Guan

2017-12-01

Conclusions: The increase of cord blood bilirubin effectively predict the occurrence of neonatal hyperbilirubinemia. There is a good correlation between levels of transcutaneous bilirubin and serum bilirubin. Moreover, combined detection of transcutaneous bilirubin and cord blood bilirubin can significantly improve the prediction accuracy of hyperbilirubinemia.

Arabidopsis thaliana glucuronosyltransferase in family GT14

DEFF Research Database (Denmark)

Dilokpimol, Adiphol; Geshi, Naomi

2014-01-01

Arabinogalactan proteins are abundant cell-surface proteoglycans in plants and are involved in many cellular processes including somatic embryogenesis, cell-cell interactions, and cell elongation. We reported a glucuronosyltransferase encoded by Arabidopsis AtGlcAT14A, which catalyzes an addition...

Glucuronidation as a mechanism of intrinsic drug resistance in colon cancer cells: contribution of drug transport proteins

NARCIS (Netherlands)

Cummings, Jeffrey; Zelcer, Noam; Allen, John D.; Yao, Denggao; Boyd, Gary; Maliepaard, Mark; Friedberg, Thomas H.; Smyth, John F.; Jodrell, Duncan I.

2004-01-01

We have recently shown that drug conjugation catalysed by UDP-glucuronosyltransferases (UGTs) functions as an intrinsic mechanism of resistance to the topoisomerase I inhibitors 7-ethyl-10-hydroxycamptothecin and NU/ICRF 505 in human colon cancer cells and now report on the role of drug transport in

Studying neonatal bilirubin encephalopathy with conventional MRI, MRS, and DWI

International Nuclear Information System (INIS)

Wang, Xiaoyi; Wu, Wulin; Chineah, Ashley; Liu, Fan; Liao, Weihua; Hou, Bob L.; Zhang, Ping

2008-01-01

The purpose of this study was to evaluate the diagnostic value of conventional magnetic resonance imaging (MRI), proton magnetic resonance spectroscopy ( 1 H-MRS), and diffusion-weighted imaging (DWI) for neonatal bilirubin encephalopathy. We collected conventional MRI in 24 neonates with neonatal bilirubin encephalopathy. We performed 1 H-MRS and DWI sequences to nine of the 24 patients and seven age-matched healthy control subjects. Multiple-voxel 1 H-MRS data were acquired using PRESS pulse sequence with TE=135 ms and TR=1500 ms. The spectroscopic regions of interest were the bilateral basal ganglia and thalamus with a 1.0 mL spatial resolution. The data from DWI were collected by using a single shot-spin echo-echo planar imaging sequence with TR/TE: 2900/98, and imaging regions were also focused on the bilateral basal ganglia and thalamus. Nineteen of the 24 patients had abnormal T 1 -weighted image hyperintensity in the globus pallidus, but these lesions appeared as normal T 2 -weighted image intensity in the same region. Ten of the 24 patients had T 1 -weighted image high signal intensity in the subthalamic nucleus and appeared as normal intensity in the region for the T 2 -weighted images. The peak area ratios of NAA/Cho and NAA/Cr were significantly decreased (t-test, P 1 H-MRS are important complementary tools in the diagnosis of neonatal bilirubin encephalopathy. The study provides important information for applying these MR modalities to evaluate neonates with bilirubin encephalopathy. (orig.)

Unconjugated free bilirubin in preterm infants.

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van der Schoor, Lori W E; Dijk, Peter H; Verkade, Henkjan J; Kamsma, Anna C J; Schreuder, Andrea B; Groen, Henk; Hulzebos, Christian V

Hyperbilirubinemia guidelines are based on total serum bilirubin (TSB), in combination with either gestational age (GA) or birth weight (BW), postnatal age and specific risk factors. However, TSB is a poor predictor of bilirubin-induced neurotoxicity (BIND). Free unconjugated bilirubin (UCBfree) and the UCBfree/TSB ratio are more directly related to BIND, but data on their postnatal courses are unknown. To characterize the postnatal courses of UCBfree and UCBfree/TSB ratio, and assess their relationships with clinical characteristics. 72 preterm infants≤32weeks GA, admitted to the University Medical Center Groningen, The Netherlands. During the first postnatal week, bilirubin plasma parameters were analyzed and their relationship with clinical parameters was analyzed. Postnatal changes were analyzed using Generalized Estimating Equations. Data are expressed as medians [ranges]. Less than 10% of the cohort (GA: 29 [26-31] weeks; BW: 1165 [600-1975] g) showed hyperbilirubinemic risk factors. We observed a large variation in UCBfree (27 [1-197] nmol/L), that could partly be explained by postnatal age and gender, but not by other risk factors. Maximal UCBfree levels of 50 [13-197] nmol/L occurred at day 4 and were higher in males. In contrast to TSB, UCBfree/TSB ratios (0.19 [0.01-1.04]) were higher in infants with low GA/BW. UCBfree levels vary considerably in preterm infants, despite a low incidence of hyperbilirubinemic risk factors and similar TSB-based phototherapy treatment. UCBfree could not be predicted by GA or BW, but UCBfree/TSB ratios are highest in the smallest preterms, while they have the lowest TSB levels. Copyright © 2017 Elsevier B.V. All rights reserved.

Relationship between serum total bilirubin levels and mortality in uremia patients undergoing long-term hemodialysis: A nationwide cohort study.

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Su, Hui-Hsien; Kao, Chia-Man; Lin, Yi-Chun; Lin, Yen-Chung; Kao, Chih-Chin; Chen, Hsi-Hsien; Hsu, Chih-Cheng; Chen, Kuan-Chou; Peng, Chiung-Chi; Wu, Mai-Szu

2017-10-01

Previous studies show that serum bilirubin has potent antioxidant effect and is associated with protection from kidney damage and reduce cardiovascular events. The aim of this study was to examine the association of serum total bilirubin level and mortality in uremia patients who underwent hemodialysis. This is a nationwide retrospective long-term cohort study. Patients were registered in the Taiwan Renal Registry Data System (TWRDS) from 2005 to 2012. A total of 115,535 hemodialysis patients were surveyed and those with valid baseline total bilirubin (TB) data were enrolled. All-cause mortality was the primary outcome. A total of 47,650 hemodialysis patients followed for 27.6 ± 12 months, were divided into 3 groups according to different baseline serum total bilirubin levels (0.1-0.3, 0.3-0.7, 0.7-1.2 mg/dL). Mean age was 61.4 ± 13.6 years, 50% were male, 13% were hepatitis B carriers, and 20% were hepatitis C carriers. Primary outcome was the 3-year mortality. The TB level 0.7-1.2 mg/dL group had high mortality, statistically significant hazard ratio of mortality was 1.14 (crude HR, 95% 1.07-1.20, p bilirubin on hemodialysis patients are needed. Copyright © 2017 Elsevier B.V. All rights reserved.

Usefulness of the bilirubin/albumin ratio for predicting bilirubin-induced neurotoxicity in premature infants

NARCIS (Netherlands)

Hulzebos, C. V.; van Imhoff, D. E.; Bos, A. F.; Ahlfors, C. E.; Verkade, H. J.; Dijk, P. H.

Unconjugated hyperbilirubinaemia occurs in almost all premature infants and is potentially neurotoxic. Treatment is based on total serum bilirubin (TSB), but treatment thresholds are not evidence based. Free bilirubin (Bf) - that is, not bound to albumin, seems a better parameter for bilirubin

The Bilirubin Binding Panel: A Henderson-Hasselbalch Approach to Neonatal Hyperbilirubinemia.

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Ahlfors, Charles E

2016-10-01

Poor plasma bilirubin binding increases the risk of bilirubin neurotoxicity in newborns with hyperbilirubinemia. New laboratory tests may soon make it possible to obtain a complete bilirubin binding panel when evaluating these babies. The 3 measured components of the panel are the plasma total bilirubin concentration (B Total ), which is currently used to guide clinical care; the bilirubin binding capacity (BBC); and the concentration of non-albumin bound or free bilirubin (B Free ). The fourth component is the bilirubin-albumin equilibrium dissociation constant, K D , which is calculated from B Total , BBC, and B Free The bilirubin binding panel is comparable to the panel of components used in the Henderson-Hasselbalch approach to acid-base assessment. Bilirubin binding population parameters (not prospective studies to determine whether the new bilirubin binding panel components are better predictors of bilirubin neurotoxicity than B Total ) are needed to expedite the clinical use of bilirubin binding. At any B Total , the B Free and the relative risk of bilirubin neurotoxicity increase as the K D /BBC ratio increases (ie, bilirubin binding worsens). Comparing the K D /BBC ratio of newborns with B Total of concern with that typical for the population helps determine whether the risk of bilirubin neurotoxicity varies significantly from the inherent risk at that B Total Furthermore, the bilirubin binding panel individualizes care because it helps to determine how aggressive intervention should be at any B Total , irrespective of whether it is above or below established B Total guidelines. The bilirubin binding panel may reduce anxiety, costs, unnecessary treatment, and the likelihood of undetected bilirubin neurotoxicity. Copyright © 2016 by the American Academy of Pediatrics.

Acute Alcohol Consumption Elevates Serum Bilirubin, an Endogenous Antioxidant

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O’Malley, Stephanie S.; Gueorguieva, Ralitza; Wu, Ran; Jatlow, Peter I.

2015-01-01

Background Moderate alcohol consumption has been associated with both negative and favorable effects on health. The mechanisms responsible for reported favorable effects remain unclear. Higher (not necessarily elevated) concentrations of serum bilirubin, an antioxidant, have also been associated with reduced risk of cardiovascular disease and all-cause mortality. This study tests the hypothesis that single dose alcohol consumption elevates bilirubin providing a potential link between these observations. Methods 18 healthy individuals (8 cigarette smokers) were administered alcohol, calibrated to achieve blood concentrations of 20, 80 and 120 mg/dL, in random order in 3 laboratory sessions separated by a week. Each session was preceded by and followed by 5–7 days of alcohol abstinence. Serum bilirubin was measured at 7:45 am prior to drinking, at 2 pm, and at 7:45 the next morning. Mixed effects regression models compared baseline and 24 hr. post-drinking bilirubin concentrations. Results Total serum bilirubin (sum of indirect and direct) concentration increased significantly after drinking from baseline to 24 hours in non-smokers (from Mean=0.38, SD=0.24 to Mean=0.51 SD=0.30, F(1, 32.2) =24.24, pbilirubin concentration and the ratio of indirect (unconjugated) to direct (conjugated) bilirubin also increased significantly. Conclusions Alcohol consumption leads to increases in serum bilirubin in nonsmokers. Considering the antioxidant properties of bilirubin, our findings suggest one possible mechanism for the reported association between alcohol consumption and reduced risk of some disorders that could be tested in future longitudinal studies. PMID:25707709

Bilirubin metabolism in the spiny dogfish, Squalus acanthias, and the small skate, Raja erinacea

NARCIS (Netherlands)

Jansen, P. L.; Arias, I. M.

1977-01-01

1. The main bilirubin conjugate in bile of spiny dogfish (Squalus Acanthias) and small skate (Raja Erinacea) is bilirubin monoglucuronide. 2. Microsomal preparations from dogfish and small skate liver have similar bilirubin UDPglucuronyltransferase (UDPGT) activity and catalyze the conjugation of

Biology of Bilirubin Photoisomers.

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Hansen, Thor Willy Ruud

2016-06-01

Phototherapy is the main treatment for neonatal hyperbilirubinemia. In acute treatment of extreme hyperbilirubinemia, intensive phototherapy may have a role in 'detoxifying' the bilirubin molecule to more polar photoisomers, which should be less prone to crossing the blood-brain barrier, providing a 'brain-sparing' effect. This article reviews the biology of bilirubin isomers. Although there is evidence supporting the lower toxicity of bilirubin photoisomers, there are studies showing the opposite. There are methodologic weaknesses in most studies and better-designed experiments are needed. In an infant acutely threatened by bilirubin-induced brain damage, intensified phototherapy should be used expediently and aggressively. Copyright © 2016 Elsevier Inc. All rights reserved.

A microscopic evaluation of collagen-bilirubin interactions: in vitro surface phenomenon.

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Usharani, N; Jayakumar, G C; Rao, J R; Chandrasekaran, B; Nair, B U

2014-02-01

This study is carried out to understand the morphology variations of collagen I matrices influenced by bilirubin. The characteristics of bilirubin interaction with collagen ascertained using various techniques like XRD, CLSM, fluorescence, SEM and AFM. These techniques are used to understand the distribution, expression and colocalization patterns of collagen-bilirubin complexes. The present investigation mimic the in vivo mechanisms created during the disorder condition like jaundice. Fluorescence technique elucidates the crucial role played by bilirubin deposition and interaction during collagen organization. Influence of bilirubin during collagen fibrillogenesis and banding patterns are clearly visualize using SEM. As a result, collagen-bilirubin complex provides different reconstructed patterns because of the influence of bilirubin concentration. Selectivity, specificity and spatial organization of collagen-bilirubin are determined through AFM imaging. Consequently, it is observed that the morphology and quantity of the bilirubin binding to collagen varied by the concentrations and the adsorption rate in protein solutions. Microscopic studies of collagen-bilirubin interaction confirms that bilirubin influence the fibrillogenesis and alter the rate of collagen organization depending on the bilirubin concentration. This knowledge helps to develop a novel drug to inhibit the interface point of interaction between collagen and bilirubin. © 2013 The Authors Journal of Microscopy © 2013 Royal Microscopical Society.

Conformational analysis and circular dichroism of bilirubin, the yellow pigment of jaundice

Science.gov (United States)

Lightner, David A.; Person, Richard; Peterson, Blake; Puzicha, Gisbert; Pu, Yu-Ming; Bojadziev, Stefan

1991-06-01

Conformational analysis of (4Z, 15Z)-bilirubin-IX(alpha) by molecular mechanics computations reveals a global energy minimum folded conformation. Powerful added stabilization is achieved through intramolecular hydrogen bonding. Theoretical treatment of bilirubin as a molecular exciton predicts an intense bisignate circular dichroism spectrum for the folded conformation: (Delta) (epsilon) is congruent to 270 L (DOT) mole-1 (DOT) cm-1 for the $OM450 nm electronic transition(s). Synthesis of bilirubin analogs with propionic acid groups methylated at the (alpha) or (beta) position introduces an allosteric effect that allows for an optical resolution of the pigments, with enantiomers exhibiting the theoretically predicted circular dichroism.

Evolution of a major drug metabolizing enzyme defect in the domestic cat and other felidae: phylogenetic timing and the role of hypercarnivory.

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Binu Shrestha

2011-03-01

Full Text Available The domestic cat (Felis catus shows remarkable sensitivity to the adverse effects of phenolic drugs, including acetaminophen and aspirin, as well as structurally-related toxicants found in the diet and environment. This idiosyncrasy results from pseudogenization of the gene encoding UDP-glucuronosyltransferase (UGT 1A6, the major species-conserved phenol detoxification enzyme. Here, we established the phylogenetic timing of disruptive UGT1A6 mutations and explored the hypothesis that gene inactivation in cats was enabled by minimal exposure to plant-derived toxicants. Fixation of the UGT1A6 pseudogene was estimated to have occurred between 35 and 11 million years ago with all extant Felidae having dysfunctional UGT1A6. Out of 22 additional taxa sampled, representative of most Carnivora families, only brown hyena (Parahyaena brunnea and northern elephant seal (Mirounga angustirostris showed inactivating UGT1A6 mutations. A comprehensive literature review of the natural diet of the sampled taxa indicated that all species with defective UGT1A6 were hypercarnivores (>70% dietary animal matter. Furthermore those species with UGT1A6 defects showed evidence for reduced amino acid constraint (increased dN/dS ratios approaching the neutral selection value of 1.0 as compared with species with intact UGT1A6. In contrast, there was no evidence for reduced amino acid constraint for these same species within UGT1A1, the gene encoding the enzyme responsible for detoxification of endogenously generated bilirubin. Our results provide the first evidence suggesting that diet may have played a permissive role in the devolution of a mammalian drug metabolizing enzyme. Further work is needed to establish whether these preliminary findings can be generalized to all Carnivora.

Broad spectrum detoxification: the major longevity assurance process regulated by insulin/IGF-1 signaling?

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Gems, David; McElwee, Joshua J

2005-03-01

Our recent survey of genes regulated by insulin/IGF-1 signaling (IIS) in Caenorhabditis elegans suggests a role for a number of gene classes in longevity assurance. Based on these findings, we propose a model for the biochemistry of longevity assurance and ageing, which is as follows. Ageing results from molecular damage from highly diverse endobiotic toxins. These are stochastic by-products of diverse metabolic processes, of which reactive oxygen species (ROS) are likely to be only one component. Our microarray analysis suggests a major role in longevity assurance of the phase 1, phase 2 detoxification system involving cytochrome P450 (CYP), short-chain dehydrogenase/reductase (SDR) and UDP-glucuronosyltransferase (UGT) enzymes. Unlike superoxide and hydrogen peroxide detoxification, this system is energetically costly, and requires the excretion from the cell of its products. Given such costs, its activity may be selected against, as predicted by the disposable soma theory. CYP and UGT enzymes target lipophilic molecular species; insufficient activity of this system is consistent with age-pigment (lipofuscin) accumulation during ageing. We suggest that IIS-regulated longevity assurance involves: (a) energetically costly detoxification and excretion of molecular rubbish, and (b) conservation of existing proteins via molecular chaperones. Given the emphasis in this theory on investment in cellular waste disposal, and on protein conservation, we have dubbed it the green theory.

Operational impact of using a vanadate oxidase method for direct bilirubin measurements at an academic medical center clinical laboratory

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Neha Dhungana

2017-08-01

Full Text Available Objectives: The aim of this study was to compare the operational impact of using vanadate oxidase versus diazo direct bilirubin assays for an academic medical center patient population. Design and methods: Retrospective study was done over an approximately 3.5 year period. The main automated chemistry instrumentation was a Roche Diagnostics cobas 8000 line. The Roche Direct Bilirubin assay was compared to Diazyme Laboratories Direct Bilirubin Assay and Randox Laboratories Direct Bilirubin assay using manufacturer's guidelines for hemolysis index, lipemia index, and analytical measurement range (AMR. Results: Retrospective data was analyzed for 47,333 serum/plasma specimens that had clinical orders for direct bilirubin. A total of 5943 specimens (12.6% exceeded the hemolysis index limit for the Roche method compared to only 0.2% and 0.05% of specimens for the Diazyme and Randox methods, respectively. The impact was particularly large on patients less than 2 years old, for which 51.3% of specimens exceeded the hemolysis index for the Roche method. A total of 1671 specimens (3.5% exceeded the lipemia index limit for the Roche method compared to less than 0.1% for the Randox method. Lastly, 988 (2.1% of specimens had direct bilirubin concentrations exceeding the upper AMR limit of 10 mg/dL [171 µmol/L] for the Roche assay compared to less than 1% of specimens for the vanadate oxidase methods. Conclusions: Vanadate oxidase direct bilirubin methods offer advantages over diazo methods in terms of less interference by hemolysis and lipemia, as well as wider AMR. The advantages are particularly evident for neonatal and infant populations. Keywords: Bilirubin, Clinical chemistry tests, Hemolysis, Hyperlipidemias, Jaundice, Photometry

An alpha-glucose-1-phosphate phosphodiesterase is present in rat liver cytosol

International Nuclear Information System (INIS)

Srisomsap, C.; Richardson, K.L.; Jay, J.C.; Marchase, R.B.

1989-01-01

UDP-glucose:glycoprotein glucose-1-phosphotransferase (Glc-phosphotransferase) catalyzes the transfer of alpha-Glc-1-P from UDP-Glc to mannose residues on acceptor glycoproteins. The predominant acceptor for this transfer in both mammalian cells and Paramecium is a cytoplasmic glycoprotein of 62-63 kDa. When cytoplasmic proteins from rat liver were fractionated by preparative isoelectric focusing following incubation of a liver homogenate with the 35S-labeled phosphorothioate analogue of UDP-Glc ([beta-35S]UDP-Glc), the acceptor was found to have a pI of about 6.0. This fraction, when not labeled prior to the focusing, became very heavily labeled when mixed with [beta-35S]. UDP-Glc and intact liver microsomes, a rich source of the Glc-phosphotransferase. In addition, it was observed that the isoelectric fractions of the cytosol having pI values of 2-3.2 contained a degradative activity, alpha-Glc-1-P phosphodiesterase, that was capable of removing alpha-Glc-1-P, monitored through radioactive labeling both in the sugar and the phosphate, as an intact unit from the 62-kDa acceptor. Identification of the product of this cleavage was substantiated by its partial transformation to UDP-Glc in the presence of UTP and UDP-Glc pyrophosphorylase. The alpha-Glc-1-P phosphodiesterase had a pH optimum of 7.5 and was not effectively inhibited by any of the potential biochemical inhibitors that were tested. Specificity for the Glc-alpha-1-P-6-Man diester was suggested by the diesterase's inability to degrade UDP-Glc or glucosylphosphoryldolichol. This enzyme may be important in the regulation of secretion since the alpha-Glc-1-P present on the 62-kDa phosphoglycoprotein appears to be removed and then rapidly replaced in response to secretagogue

Bilirubin present in diverse angiosperms.

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Pirone, Cary; Johnson, Jodie V; Quirke, J Martin E; Priestap, Horacio A; Lee, David

2010-01-01

Bilirubin is an orange-yellow tetrapyrrole produced from the breakdown of heme by mammals and some other vertebrates. Plants, algae and cyanobacteria synthesize molecules similar to bilirubin, including the protein-bound bilins and phytochromobilin which harvest or sense light. Recently, we discovered bilirubin in the arils of Strelitzia nicolai, the White Bird of Paradise Tree, which was the first example of this molecule in a higher plant. Subsequently, we identified bilirubin in both the arils and the flowers of Strelitzia reginae, the Bird of Paradise Flower. In the arils of both species, bilirubin is present as the primary pigment, and thus functions to produce colour. Previously, no tetrapyrroles were known to generate display colour in plants. We were therefore interested in determining whether bilirubin is broadly distributed in the plant kingdom and whether it contributes to colour in other species. In this paper, we use HPLC/UV and HPLC/UV/electrospray ionization-tandem mass spectrometry (HPLC/UV/ESI-MS/MS) to search for bilirubin in 10 species across diverse angiosperm lineages. Bilirubin was present in eight species from the orders Zingiberales, Arecales and Myrtales, but only contributed to colour in species within the Strelitziaceae. The wide distribution of bilirubin in angiosperms indicates the need to re-assess some metabolic details of an important and universal biosynthetic pathway in plants, and further explore its evolutionary history and function. Although colour production was limited to the Strelitziaceae in this study, further sampling may indicate otherwise.

No effect modification of serum bilirubin or coffee consumption on the association of gamma-glutamyltransferase with glycated hemoglobin in a cross-sectional study of Japanese men and women

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Wang Zhenjie

2012-10-01

Full Text Available Abstract Background Oxidative stress has been implicated in the development of type 2 diabetes mellitus. Bilirubin is a potent endogenous antioxidant, and coffee is a major source of exogenous antioxidants. Serum gamma-glutamyltransferase (GGT, a marker of oxidative stress, is a strong predictor of the risk of type 2 diabetes mellitus. This study evaluated the effect modification of bilirubin and coffee consumption on the association of serum GGT with glycated hemoglobin (HbA1c and the combined effect of bilirubin and coffee on HbA1c concentrations. Methods The subjects were 4492 men and 6242 women aged 49–76 years who participated in the baseline survey of an on-going cohort study on lifestyle-related diseases in Fukuoka, Japan. Geometric means of HbA1c were examined according to quartile categories of GGT, with stratification by serum total bilirubin (≥ 0.6 mg/dL versus less in men and ≥ 0.5 mg/dL versus less in women and coffee consumption ( Results HbA1 concentrations increased progressively with increasing levels of GGT in both men and women. The increasing trend of HbA1c concentrations associated with GGT did not differ by either bilirubin status or coffee consumption. Both men and women with high bilirubin had consistently lower concentrations of HbA1c across the GGT quartiles. Higher coffee consumption was associated with lower concentrations of HbA1c in women with low bilirubin (trend P = 0.04, but not with high bilirubin (trend P = 0.37. There was no such association between coffee and HbA1c in men with either low or high bilirubin levels. Conclusions Bilirubin is possibly protective against deterioration of glucose metabolism. Further studies are needed regarding the combined effect of bilirubin and coffee on glucose metabolism.

Astrocyte reactivity to unconjugated bilirubin requires TNF-α and IL-1β receptor signaling pathways.

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Fernandes, Adelaide; Barateiro, Andreia; Falcão, Ana Sofia; Silva, Sandra Leit-Ao; Vaz, Ana Rita; Brito, Maria Alexandra; Silva, Rui Fernando Marques; Brites, Dora

2011-01-01

Jaundice and sepsis are common neonatal conditions that can lead to neurodevelopment sequelae, namely if present at the same time. We have reported that tumor necrosis factor (TNF)-α and interleukin (IL)-1β are produced by cultured neurons and mainly by glial cells exposed to unconjugated bilirubin (UCB). The effects of these cytokines are mediated by cell surface receptors through a nuclear factor (NF)-κB-dependent pathway that we have showed to be activated by UCB. The present study was designed to evaluate the role of TNF-α and IL-1β signaling on astrocyte reactivity to UCB in rat cortical astrocytes. Exposure of astrocytes to UCB increased the expression of both TNF-α receptor (TNFR)1 and IL-1β receptor (IL-1R)1, but not TNFR2, as well as their activation, observed by augmented binding of receptors' molecular adaptors, TRAF2 and TRAF6, respectively. Silencing of TNFR1, using siRNA technology, or blockade of IL-1β cascade, using its endogenous antagonist, IL-1 receptor antagonist (IL-1ra), prevented UCB-induced cytokine release and NF-κB activation. Interestingly, lack of TNF-α signal transduction reduced UCB-induced cell death for short periods of incubation, although an increase was observed after extended exposure; in contrast, inhibition of IL-1β cascade produced a sustained blockade of astrocyte injury by UCB. Together, our data show that inflammatory pathways are activated during in vitro exposure of rat cortical astrocytes to UCB and that this activation is prolonged in time. This supports the concept that inflammatory pathways play a role in brain damage by UCB, and that they may represent important pharmacological targets. Copyright © 2010 Wiley-Liss, Inc.

Operational impact of using a vanadate oxidase method for direct bilirubin measurements at an academic medical center clinical laboratory.

Science.gov (United States)

Dhungana, Neha; Morris, Cory; Krasowski, Matthew D

2017-08-01

The aim of this study was to compare the operational impact of using vanadate oxidase versus diazo direct bilirubin assays for an academic medical center patient population. Retrospective study was done over an approximately 3.5 year period. The main automated chemistry instrumentation was a Roche Diagnostics cobas 8000 line. The Roche Direct Bilirubin assay was compared to Diazyme Laboratories Direct Bilirubin Assay and Randox Laboratories Direct Bilirubin assay using manufacturer's guidelines for hemolysis index, lipemia index, and analytical measurement range (AMR). Retrospective data was analyzed for 47,333 serum/plasma specimens that had clinical orders for direct bilirubin. A total of 5943 specimens (12.6%) exceeded the hemolysis index limit for the Roche method compared to only 0.2% and 0.05% of specimens for the Diazyme and Randox methods, respectively. The impact was particularly large on patients less than 2 years old, for which 51.3% of specimens exceeded the hemolysis index for the Roche method. A total of 1671 specimens (3.5%) exceeded the lipemia index limit for the Roche method compared to less than 0.1% for the Randox method. Lastly, 988 (2.1%) of specimens had direct bilirubin concentrations exceeding the upper AMR limit of 10 mg/dL [171 µmol/L] for the Roche assay compared to less than 1% of specimens for the vanadate oxidase methods. Vanadate oxidase direct bilirubin methods offer advantages over diazo methods in terms of less interference by hemolysis and lipemia, as well as wider AMR. The advantages are particularly evident for neonatal and infant populations.

Hepatic bilirubin uptake in the isolated perfused rat liver is not facilitated by albumin binding

International Nuclear Information System (INIS)

Stollman, Y.R.; Gaertner, U.; Theilmann, L.; Ohmi, N.; Wolkoff, A.W.

1983-01-01

Bilirubin uptake by the liver has kinetic characteristics which suggest carrier-mediation. Bilirubin is readily bound to albumin. A liver cell surface receptor for albumin has been postulated. The present study was designed to examine directly whether albumin facilitates the hepatic uptake of bilirubin and whether uptake of bilirubin depends on binding to albumin. Rat liver was perfused with a protein-free fluorocarbon medium, and single-pass uptake of 1, 10, or 200 nmol of [ 3 H]bilirubin was determined after injection as an equimolar complex with 125 I-albumin, with 125 I-ligandin, or free with only a [ 14 C]sucrose reference. Uptake of 10 nmol of [ 3 H]bilirubin was 67.5 +/- 3.7% of the dose when injected with 125 I-albumin, 67.4 +/- 6.5% when injected with 125 I-ligandin, and 74.9 +/- 2.4% when injected with [ 14 C]sucrose (P greater than 0.1). At 200 nmol, uptake fell to 46.4 +/- 3.1% ( 125 I-albumin) and 63.3 +/- 3.4% [( 14 C]sucrose) of injected [ 3 H]bilirubin (P less than 0.01), which suggests saturation of the uptake mechanism. When influx was quantitated by the model of Goresky, similar results were obtained. When [ 3 H]bilirubin was injected simultaneously with equimolar 125 I-albumin and a [ 14 C]sucrose reference, there was no delay in 125 I-albumin transit as compared with that of [ 14 C]sucrose. This suggested that the off-rate of albumin from a putative hepatocyte receptor would have to be very rapid, which is unusual for high affinity receptor-ligand interaction. There was no evidence for facilitation of bilirubin uptake by binding to albumin or for interaction of albumin with a liver cell surface receptor. These results suggest that the hepatic bilirubin uptake mechanism is one of high affinity which can extract bilirubin from circulating carriers such as albumin, ligandin, or fluorocarbon

Bilirubin: an endogenous molecule with antiviral activity in vitro.

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Rosaria eSantangelo

2012-03-01

Full Text Available Bilirubin-IX-alpha (BR is the final product of heme metabolism through the heme oxygenase/biliverdin reductase (HO/BVR system. Previous papers reported on the microbicidal effects of the HO by-products biliverdin-IX-alpha, carbon monoxide and iron, through either direct or indirect mechanisms. In this paper the evidence of a virucidal effect of BR against human herpes simplex virus type 1 (HSV-1 and the enterovirus EV71 was provided. Bilirubin-IX-alpha, at concentrations 1-10 µM, close to those found in blood and tissues, significantly reduced HSV-1 and EV71 replication in Hep-2 and Vero cell lines, respectively. Bilirubin-IX-alpha inhibited viral infection of Hep-2 and Vero cells when given 2 hours before, concomitantly and 2 hours after viral infection. Furthermore, BR retained its antiviral activity even complexed with a saturating concentration of human serum-albumin. Moreover, 10 µM BR increased the formation of nitric oxide and the phosphorylation of JNK in Vero and Hep-2 cell lines, respectively, thus implying a role of these two pathways in the mechanism of antiviral activity of the bile pigment. In conclusion, these results support the antiviral effect of BR against HSV-1 and enterovirus in vitro, and put the basis for further basic and clinical studies to understand the real role of BR as an endogenous antiviral molecule.

Enhanced thyroid hormone breakdown in hepatocytes by mutual induction of the constitutive androstane receptor (CAR, NR1I3) and arylhydrocarbon receptor by benzo[a]pyrene and phenobarbital.

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Schraplau, Anne; Schewe, Bettina; Neuschäfer-Rube, Frank; Ringel, Sebastian; Neuber, Corinna; Kleuser, Burkhard; Püschel, Gerhard P

2015-02-03

Xenobiotics may interfere with the hypothalamic-pituitary-thyroid endocrine axis by inducing enzymes that inactivate thyroid hormones and thereby reduce the metabolic rate. This induction results from an activation of xeno-sensing nuclear receptors. The current study shows that benzo[a]pyrene, a frequent contaminant of processed food and activator of the arylhydrocarbon receptor (AhR) activated the promoter and induced the transcription of the nuclear receptor constitutive androstane receptor (CAR, NR1I3) in rat hepatocytes. Likewise, phenobarbital induced the AhR transcription. This mutual induction of the nuclear receptors enhanced the phenobarbital-dependent induction of the prototypic CAR target gene Cyp2b1 as well as the AhR-dependent induction of UDP-glucuronosyltransferases. In both cases, the induction by the combination of both xenobiotics was more than the sum of the induction by either substance alone. By inducing the AhR, phenobarbital enhanced the benzo[a]pyrene-dependent reduction of thyroid hormone half-life and the benzo[a]pyrene-dependent increase in the rate of thyroid hormone glucuronide formation in hepatocyte cultures. CAR ligands might thus augment the endocrine disrupting potential of AhR activators by an induction of the AhR. Copyright © 2014. Published by Elsevier Ireland Ltd.

Preliminary development of a fiber optic sensor for measuring bilirubin.

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Babin, Steven M; Sova, Raymond M

2014-01-01

Preliminary development of a fiber optic bilirubin sensor is described, where an unclad sensing portion is used to provide evanescent wave interaction of the transmitted light with the chemical environment. By using a wavelength corresponding to a bilirubin absorption peak, the Beer-Lambert Law can be used to relate the concentration of bilirubin surrounding the sensing portion to the amount of absorbed light. Initial testing in vitro suggests that the sensor response is consistent with the results of bulk absorption measurements as well as the Beer-Lambert Law. In addition, it is found that conjugated and unconjugated bilirubin have different peak absorption wavelengths, so that two optical frequencies may potentially be used to measure both types of bilirubin. Future development of this device could provide a means of real-time, point-of-care monitoring of intravenous bilirubin in critical care neonates with hyperbilirubinemia.

The effect of UGT1A1 promoter polymorphism in the development of hyperbilirubinemia and cholelithiasis in hemoglobinopathy patients.

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Suad AlFadhli

Full Text Available Present study was aimed to explore the effect of (TAn UGT1A1 gene promoter polymorphism on bilirubin metabolism, bilirubinaemia, predisposition to cholelithiasis and subsequent cholecystectomy, in Sickle-Cell Anemia (SCA and beta-Thalasemia major (bTH in Kuwaiti subjects compared to other population. This polymorphism was analyzed and correlated to total bilirubin and cholelithiasis in 270 age, gender, ethnically matched subjects (92 bTH, 116 SCA and 62 Controls using PCR, dHPLC, fragment analysis and direct sequencing. Four genotypes of UGT1A1 were detected in this study (TA6/6, TA6/7, TA6/8 and TA7/7. (TA6/8 was found only in four individuals; hence it was not included in the analysis. There was a statistically significant association of genotypes with serum total bilirubin levels in both bTH and SCA groups (p<0.001. Subjects with (TA7/7 had the highest total serum bilirubin level (178.7 ± 3.5 µmole/l. A significant association was observed between allele (TA7 and cholelithiasis development (p = 0.0001. The 40%, 67.5% and 100% of SCA with (TA6/6, (TA6/7 and (TA7/7 respectively developed cholelithiasis and were subsequently cholecystectomized. Our results confirm UGT1A1 (TA7 allele as one of the factors accounting for the hyperbilirubinemia and cholelithiasis observed in SCA and bTH.

Preliminary Development of a Fiber Optic Sensor for Measuring Bilirubin

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Steven M. Babin

2014-01-01

Full Text Available Preliminary development of a fiber optic bilirubin sensor is described, where an unclad sensing portion is used to provide evanescent wave interaction of the transmitted light with the chemical environment. By using a wavelength corresponding to a bilirubin absorption peak, the Beer–Lambert Law can be used to relate the concentration of bilirubin surrounding the sensing portion to the amount of absorbed light. Initial testing in vitro suggests that the sensor response is consistent with the results of bulk absorption measurements as well as the Beer–Lambert Law. In addition, it is found that conjugated and unconjugated bilirubin have different peak absorption wavelengths, so that two optical frequencies may potentially be used to measure both types of bilirubin. Future development of this device could provide a means of real-time, point-of-care monitoring of intravenous bilirubin in critical care neonates with hyperbilirubinemia.

Metabolism of bilirubin by human cytochrome P450 2A6

Energy Technology Data Exchange (ETDEWEB)

Abu-Bakar, A' edah, E-mail: a.abubakar@uq.edu.au [The University of Queensland, National Research Centre for Environmental Toxicology (Entox), 4072 Brisbane, Queensland (Australia); Arthur, Dionne M. [The University of Queensland, National Research Centre for Environmental Toxicology (Entox), 4072 Brisbane, Queensland (Australia); Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, Adelaide (Australia); Wikman, Anna S. [The University of Queensland, National Research Centre for Environmental Toxicology (Entox), 4072 Brisbane, Queensland (Australia); Department of Pharmaceutical Biosciences, Uppsala University, SE-75123 Uppsala (Sweden); Rahnasto, Minna; Juvonen, Risto O.; Vepsäläinen, Jouko; Raunio, Hannu [School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, POB 1627, 70211 Kuopio (Finland); Ng, Jack C. [The University of Queensland, National Research Centre for Environmental Toxicology (Entox), 4072 Brisbane, Queensland (Australia); Cooperative Research Centre for Contamination Assessment and Remediation of the Environment, Adelaide (Australia); Lang, Matti A. [The University of Queensland, National Research Centre for Environmental Toxicology (Entox), 4072 Brisbane, Queensland (Australia)

2012-05-15

The mouse cytochrome P450 (CYP) 2A5 has recently been shown to function as hepatic “Bilirubin Oxidase” (Abu-Bakar, A., et al., 2011. Toxicol. Appl. Pharmacol. 257, 14–22). To date, no information is available on human CYP isoforms involvement in bilirubin metabolism. In this paper we provide novel evidence for human CYP2A6 metabolising the tetrapyrrole bilirubin. Incubation of bilirubin with recombinant yeast microsomes expressing the CYP2A6 showed that bilirubin inhibited CYP2A6-dependent coumarin 7-hydroxylase activity to almost 100% with an estimated K{sub i} of 2.23 μM. Metabolite screening by a high-performance liquid chromatography/electrospray ionisation mass spectrometry indicated that CYP2A6 oxidised bilirubin to biliverdin and to three other smaller products with m/z values of 301, 315 and 333. Molecular docking analyses indicated that bilirubin and its positively charged intermediate interacted with key amino acid residues at the enzyme's active site. They were stabilised at the site in a conformation favouring biliverdin formation. By contrast, the end product, biliverdin was less fitting to the active site with the critical central methylene bridge distanced from the CYP2A6 haem iron facilitating its release. Furthermore, bilirubin treatment of HepG2 cells increased the CYP2A6 protein and activity levels with no effect on the corresponding mRNA. Co-treatment with cycloheximide (CHX), a protein synthesis inhibitor, resulted in increased half-life of the CYP2A6 compared to cells treated only with CHX. Collectively, the observations indicate that the CYP2A6 may function as human “Bilirubin Oxidase” where bilirubin is potentially a substrate and a regulator of the enzyme. -- Highlights: ► Human CYP2A6 interacts with bilirubin with a high affinity. ► Bilirubin docking to the CYP2A6 active site is more stable than biliverdin docking. ► Recombinant CYP2A6 microsomes metabolised bilirubin to biliverdin. ► Bilirubin increased the hepatic

Metabolism of bilirubin by human cytochrome P450 2A6

International Nuclear Information System (INIS)

Abu-Bakar, A'edah; Arthur, Dionne M.; Wikman, Anna S.; Rahnasto, Minna; Juvonen, Risto O.; Vepsäläinen, Jouko; Raunio, Hannu; Ng, Jack C.; Lang, Matti A.

2012-01-01

The mouse cytochrome P450 (CYP) 2A5 has recently been shown to function as hepatic “Bilirubin Oxidase” (Abu-Bakar, A., et al., 2011. Toxicol. Appl. Pharmacol. 257, 14–22). To date, no information is available on human CYP isoforms involvement in bilirubin metabolism. In this paper we provide novel evidence for human CYP2A6 metabolising the tetrapyrrole bilirubin. Incubation of bilirubin with recombinant yeast microsomes expressing the CYP2A6 showed that bilirubin inhibited CYP2A6-dependent coumarin 7-hydroxylase activity to almost 100% with an estimated K i of 2.23 μM. Metabolite screening by a high-performance liquid chromatography/electrospray ionisation mass spectrometry indicated that CYP2A6 oxidised bilirubin to biliverdin and to three other smaller products with m/z values of 301, 315 and 333. Molecular docking analyses indicated that bilirubin and its positively charged intermediate interacted with key amino acid residues at the enzyme's active site. They were stabilised at the site in a conformation favouring biliverdin formation. By contrast, the end product, biliverdin was less fitting to the active site with the critical central methylene bridge distanced from the CYP2A6 haem iron facilitating its release. Furthermore, bilirubin treatment of HepG2 cells increased the CYP2A6 protein and activity levels with no effect on the corresponding mRNA. Co-treatment with cycloheximide (CHX), a protein synthesis inhibitor, resulted in increased half-life of the CYP2A6 compared to cells treated only with CHX. Collectively, the observations indicate that the CYP2A6 may function as human “Bilirubin Oxidase” where bilirubin is potentially a substrate and a regulator of the enzyme. -- Highlights: ► Human CYP2A6 interacts with bilirubin with a high affinity. ► Bilirubin docking to the CYP2A6 active site is more stable than biliverdin docking. ► Recombinant CYP2A6 microsomes metabolised bilirubin to biliverdin. ► Bilirubin increased the hepatic CYP2A6

Significance and prognostic value of increased serum direct bilirubin level for lymph node metastasis in Chinese rectal cancer patients.

Science.gov (United States)

Gao, Chun; Fang, Long; Li, Jing-Tao; Zhao, Hong-Chuan

2016-02-28

To determine the significance of increased serum direct bilirubin level for lymph node metastasis (LNM) in Chinese rectal cancer patients, after those with known hepatobiliary and pancreatic diseases were excluded. A cohort of 469 patients, who were treated at the China-Japan Friendship Hospital, Ministry of Health (Beijing, China), in the period from January 2003 to June 2011, and with a pathological diagnosis of rectal adenocarcinoma, were recruited. They included 231 patients with LNM (49.3%) and 238 patients without LNM. Follow-up for these patients was taken through to December 31, 2012. The baseline serum direct bilirubin concentration was (median/inter-quartile range) 2.30/1.60-3.42 μmol/L. Univariate analysis showed that compared with patients without LNM, the patients with LNM had an increased level of direct bilirubin (2.50/1.70-3.42 vs 2.10/1.40-3.42, P = 0.025). Multivariate analysis showed that direct bilirubin was independently associated with LNM (OR = 1.602; 95%CI: 1.098-2.338, P = 0.015). Moreover, we found that: (1) serum direct bilirubin differs between male and female patients; a higher concentration was associated with poor tumor classification; (2) as the baseline serum direct bilirubin concentration increased, the percentage of patients with LNM increased; and (3) serum direct bilirubin was associated with the prognosis of rectal cancer patients and higher values indicated poor prognosis. Higher serum direct bilirubin concentration was associated with the increased risk of LNM and poor prognosis in our rectal cancers.

Membrane Transporters for Bilirubin and Its Conjugates: A Systematic Review

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Jovana Čvorović

2017-12-01

Full Text Available Background: Bilirubin is a highly-hydrophobic tetrapyrrole which binds to plasma albumin. It is conjugated in the liver to glucuronic acid, and the water-soluble glucuronides are excreted in urine and bile. The membrane transporters of bilirubin diglucuronide are well-known. Still undefined are however the transporters performing the uptake of bilirubin from the blood into the liver, a process known to be fast and not rate-limited. The biological importance of this process may be appraised by considering that in normal adults 200–300 mg of bilirubin are produced daily, as a result of the physiologic turnover of hemoglobin and cellular cytochromes. Nevertheless, research in this field has yielded controversial and contradicting results. We have undertaken a systematic review of the literature, believing in its utility to improve the existing knowledge and promote further advancements.Methods: We have sourced the PubMed database until 30 June 2017 by applying 5 sequential searches. Screening and eligibility criteria were applied to retain research articles reporting results obtained by using bilirubin molecules in membrane transport assays in vitro or by assessing serum bilirubin levels in in vivo experiments.Results: We have identified 311 articles, retaining 44, reporting data on experimental models having 6 incremental increases of complexity (isolated proteins, membrane vesicles, cells, organ fragments, in vivo rodents, and human studies, demonstrating the function of 19 membrane transporters, encoded by either SLCO or ABC genes. Three other bilirubin transporters have no gene, though one, i.e., bilitranslocase, is annotated in the Transporter Classification Database.Conclusions: This is the first review that has systematically examined the membrane transporters for bilirubin and its conjugates. Paradoxically, the remarkable advancements in the field of membrane transport of bilirubin have pointed to the elusive mechanism(s enabling

Bilirubin Binding Capacity in the Preterm Neonate.

Science.gov (United States)

Amin, Sanjiv B

2016-06-01

Total serum/plasma bilirubin (TB), the biochemical measure currently used to evaluate and manage hyperbilirubinemia, is not a useful predictor of bilirubin-induced neurotoxicity in premature infants. Altered bilirubin-albumin binding in premature infants limits the usefulness of TB in premature infants. In this article, bilirubin-albumin binding, a modifying factor for bilirubin-induced neurotoxicity, in premature infants is reviewed. Copyright © 2016 Elsevier Inc. All rights reserved.

Increased conjugated bilirubin is sufficient to initiate screening for biliary atresia

DEFF Research Database (Denmark)

Madsen, Stine Skipper; Kvist, Nina; Thorup, Jørgen

2015-01-01

INTRODUCTION: Biliary atresia is the leading cause of liver transplantation in children. It affects 1:15,000 in Denmark. With a national birth rate of 60,000, four children are born every year with biliary atresia. Early correction of biliary obstruction is essential to prevent fatal biliary...... cirrhosis. The Danish Health and Medicines Authority (DHMA) demands diagnostic evaluation of children with elevated level of serum bilirubin after two weeks of age. Biliary atresia has to be excluded if conjugated bilirubin level is above than 20 μmol/l, and/or more than 20% of total bilirubin...

Downregulation of the UDP-arabinomutase gene in switchgrass (Panicum virgatum L. results in increased cell wall lignin while reducing arabinose-glycans

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Jonathan Duran Willis

2016-10-01

Full Text Available Switchgrass (Panicum virgatum L. is a C4 perennial prairie grass and a lignocellulosic biofuels feedstock. Saccharification and biofuel yields are inhibited by the plant cell wall’s natural recalcitrance against enzymatic degradation. Plant hemicellulose polysaccharides such as arabinoxylans structurally support and crosslink other cell wall polymers. Grasses have predominately Type II cell walls that are abundant in arabinoxylan, which comprise nearly 25% of aboveground biomass. A primary component of arabinoxylan synthesis is uridine diphosphate (UDP linked to arabinofuranose (Araf. A family of UDP-arabinopyranose mutase/reversible glycosylated polypeptides (UAM/RGPs catalyze the interconversion between UDP-arabinopyranose (UDP-Arap and UDP-Araf. In switchgrass we knocked down expression of the endogenous PvUAM1 gene via RNAi to investigate its role in cell wall recalcitrance in the feedstock. PvUAM1 encodes a switchgrass homolog of UDP-arabinose mutase, which converts UDP-Arap to UDP-Araf. Each transgenic line contained between one to at least seven T-DNA insertions, resulting in some cases, a 95% reduction of native PvUAM1 transcript in stem internodes. Transgenic plants had increased pigmentation in vascular tissues at nodes, but were otherwise morphologically similar to non-transgenics. There was decreased cell wall-associated arabinose in leaves and stems by over 50%, but there was an increase in cellulose in these organs. In addition, there was a commensurate change in arabinose side chain extension. Cell wall lignin composition was altered with a concurrent increase in lignin content and transcript abundance of lignin biosynthetic genes in mature tillers. Enzymatic saccharification efficiency was unchanged in the transgenic plants relative to the control, but had increased glucose in cell walls. The increased glucose detected in stems and leaves indicates that attenuation of PvUAM1 expression might have downstream effects on starch

Persistent high serum bilirubin level after percutaneous transhepatic biliary drainage: analysis of 32 cases

International Nuclear Information System (INIS)

Choo, In Wook; Choi, Byung Ihn; Park, Jae Hyung; Han, Man Chung; Kim, Chu Wan

1986-01-01

The aim of percutaneous transhepatic biliary drainage (PTBD) is to decrease serum bilirubin level and promote liver function in patient with biliary tract disease, especially obstruction by malignant disease. But some patients showed persistent high serum bilirubin level or higher than pre-PTBD level. Percutaneous transhepatic biliary drainage was performed in 341 patients of obstructive jaundice for 5 years form July, 1981 to July, 1986 at department of radiology, Seoul National University Hospital. Follow up check of the serum bilirubin level was possible in 188 patients. Among them the authors analysed 32 patients who showed persistent high serum bilirubin level after PTBD. The results were as follows: 1. The male to female ratio was 3.4:1 and the age ranged from 33 to 75. 2. The causes of obstructive jaundice included 30 malignant diseases and 2 benign diseases. Malignant disease were 16 cases of bile duct carcinoma, 7 cases of pancreatic cancer and 7 cases of metastasis from stomach, colon and uterine cervix. Benign disease were 1 case of common hepatic duct stone and 1 case of intrahepatic duct stones. 3. The most common level of obstruction was trifurcation in 17 cases. 4. The most common indication of PTBD was palliative drainage of obstruction secondary to malignant tumor in 28 cases. 5. Change of serum bilirubin level ratio (post-PTBD level/pre-PTBD level) was 1.28, 1.22, 1.38, 1.51 in serial period of 1-3 days, 4-6 days, 1-2 week 2-3 week after PTBD. 6. Causes of persistent high serum bilirubin level after PTBD were 12 cases of partial drainage of intrahepatic bile, 13 cases of hepatic dysfunction including 9 cases of metastatic nodule, 2 cases of biliary cirrhosis, 2 cases of multiple liver abscess, and 7 cases of poor function of catheter including 4 cases of hemobilia, 1 case of multiple intrahepatic stones, pyobilia and intrahepatic Clonorchis sinensis.

Persistent high serum bilirubin level after percutaneous transhepatic biliary drainage: analysis of 32 cases

Energy Technology Data Exchange (ETDEWEB)

Choo, In Wook; Choi, Byung Ihn; Park, Jae Hyung; Han, Man Chung; Kim, Chu Wan [Seoul National University College of Medicine, Seoul (Korea, Republic of)

1986-12-15

The aim of percutaneous transhepatic biliary drainage (PTBD) is to decrease serum bilirubin level and promote liver function in patient with biliary tract disease, especially obstruction by malignant disease. But some patients showed persistent high serum bilirubin level or higher than pre-PTBD level. Percutaneous transhepatic biliary drainage was performed in 341 patients of obstructive jaundice for 5 years form July, 1981 to July, 1986 at department of radiology, Seoul National University Hospital. Follow up check of the serum bilirubin level was possible in 188 patients. Among them the authors analysed 32 patients who showed persistent high serum bilirubin level after PTBD. The results were as follows: 1. The male to female ratio was 3.4:1 and the age ranged from 33 to 75. 2. The causes of obstructive jaundice included 30 malignant diseases and 2 benign diseases. Malignant disease were 16 cases of bile duct carcinoma, 7 cases of pancreatic cancer and 7 cases of metastasis from stomach, colon and uterine cervix. Benign disease were 1 case of common hepatic duct stone and 1 case of intrahepatic duct stones. 3. The most common level of obstruction was trifurcation in 17 cases. 4. The most common indication of PTBD was palliative drainage of obstruction secondary to malignant tumor in 28 cases. 5. Change of serum bilirubin level ratio (post-PTBD level/pre-PTBD level) was 1.28, 1.22, 1.38, 1.51 in serial period of 1-3 days, 4-6 days, 1-2 week 2-3 week after PTBD. 6. Causes of persistent high serum bilirubin level after PTBD were 12 cases of partial drainage of intrahepatic bile, 13 cases of hepatic dysfunction including 9 cases of metastatic nodule, 2 cases of biliary cirrhosis, 2 cases of multiple liver abscess, and 7 cases of poor function of catheter including 4 cases of hemobilia, 1 case of multiple intrahepatic stones, pyobilia and intrahepatic Clonorchis sinensis.

In Vitro Inhibition of Human UDP-Glucuronosyl-Transferase (UGT Isoforms by Astaxanthin, β-Cryptoxanthin, Canthaxanthin, Lutein, and Zeaxanthin: Prediction of in Vivo Dietary Supplement-Drug Interactions

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Yu Fen Zheng

2016-08-01

Full Text Available Despite the widespread use of the five major xanthophylls astaxanthin, β-cryptoxanthin, canthaxanthin, lutein, and zeaxanthin as dietary supplements, there have been no studies regarding their inhibitory effects on hepatic UDP-glucuronosyltransferases (UGTs. Here, we evaluated the inhibitory potential of these xanthophylls on the seven major human hepatic UGTs (UGT1A1, UGT1A3, UGT1A4, UGT1A6, UGT1A9, UGT2B7 and UGT2B15 in vitro by LC-MS/MS using specific marker reactions in human liver microsomes (except UGT2B15 or recombinant supersomes (UGT2B15. We also predicted potential dietary supplement-drug interactions for β-cryptoxanthin via UGT1A1 inhibition. We demonstrated that astaxanthin and zeaxanthin showed no apparent inhibition, while the remaining xanthophylls showed only weak inhibitory effects on the seven UGTs. β-Cryptoxanthin mildly inhibited UGT1A1, UGT1A3, and UGT1A4, with IC50 values of 18.8 ± 2.07, 28.3 ± 4.40 and 34.9 ± 5.98 μM, respectively. Canthaxanthin weakly inhibited UGT1A1 and UGT1A3, with IC50 values of 38.5 ± 4.65 and 41.2 ± 3.14 μM, respectively; and lutein inhibited UGT1A1 and UGT1A4, with IC50 values of 45.5 ± 4.01 and 28.7 ± 3.79 μM, respectively. Among the tested xanthophyll-UGT pairs, β-cryptoxanthin showed the strongest competitive inhibition of UGT1A1 (Ki, 12.2 ± 0.985 μM. In addition, we predicted the risk of UGT1A1 inhibition in vivo using the reported maximum plasma concentration after oral administration of β-cryptoxanthin in humans. Our data suggests that these xanthophylls are unlikely to cause dietary supplement-drug interactions mediated by inhibition of the hepatic UGTs. These findings provide useful information for the safe clinical use of the tested xanthophylls.

In Vitro Inhibition of Human UDP-Glucuronosyl-Transferase (UGT) Isoforms by Astaxanthin, β-Cryptoxanthin, Canthaxanthin, Lutein, and Zeaxanthin: Prediction of in Vivo Dietary Supplement-Drug Interactions.

Science.gov (United States)

Zheng, Yu Fen; Min, Jee Sun; Kim, Doyun; Park, Jung Bae; Choi, Sung-Wook; Lee, Eun Seong; Na, Kun; Bae, Soo Kyung

2016-08-12

Despite the widespread use of the five major xanthophylls astaxanthin, β-cryptoxanthin, canthaxanthin, lutein, and zeaxanthin as dietary supplements, there have been no studies regarding their inhibitory effects on hepatic UDP-glucuronosyltransferases (UGTs). Here, we evaluated the inhibitory potential of these xanthophylls on the seven major human hepatic UGTs (UGT1A1, UGT1A3, UGT1A4, UGT1A6, UGT1A9, UGT2B7 and UGT2B15) in vitro by LC-MS/MS using specific marker reactions in human liver microsomes (except UGT2B15) or recombinant supersomes (UGT2B15). We also predicted potential dietary supplement-drug interactions for β-cryptoxanthin via UGT1A1 inhibition. We demonstrated that astaxanthin and zeaxanthin showed no apparent inhibition, while the remaining xanthophylls showed only weak inhibitory effects on the seven UGTs. β-Cryptoxanthin mildly inhibited UGT1A1, UGT1A3, and UGT1A4, with IC50 values of 18.8 ± 2.07, 28.3 ± 4.40 and 34.9 ± 5.98 μM, respectively. Canthaxanthin weakly inhibited UGT1A1 and UGT1A3, with IC50 values of 38.5 ± 4.65 and 41.2 ± 3.14 μM, respectively; and lutein inhibited UGT1A1 and UGT1A4, with IC50 values of 45.5 ± 4.01 and 28.7 ± 3.79 μM, respectively. Among the tested xanthophyll-UGT pairs, β-cryptoxanthin showed the strongest competitive inhibition of UGT1A1 (Ki, 12.2 ± 0.985 μM). In addition, we predicted the risk of UGT1A1 inhibition in vivo using the reported maximum plasma concentration after oral administration of β-cryptoxanthin in humans. Our data suggests that these xanthophylls are unlikely to cause dietary supplement-drug interactions mediated by inhibition of the hepatic UGTs. These findings provide useful information for the safe clinical use of the tested xanthophylls.

Crystal Structures of Active Fully Assembled Substrate- and Product-Bound Complexes of UDP-N-Acetylmuramic Acid:l-Alanine Ligase (MurC) from Haemophilus influenzae

OpenAIRE

Mol, Clifford D.; Brooun, Alexei; Dougan, Douglas R.; Hilgers, Mark T.; Tari, Leslie W.; Wijnands, Robert A.; Knuth, Mark W.; McRee, Duncan E.; Swanson, Ronald V.

2003-01-01

UDP-N-acetylmuramic acid:l-alanine ligase (MurC) catalyzes the addition of the first amino acid to the cytoplasmic precursor of the bacterial cell wall peptidoglycan. The crystal structures of Haemophilus influenzae MurC in complex with its substrate UDP-N-acetylmuramic acid (UNAM) and Mg2+ and of a fully assembled MurC complex with its product UDP-N-acetylmuramoyl-l-alanine (UMA), the nonhydrolyzable ATP analogue AMPPNP, and Mn2+ have been determined to 1.85- and 1.7-Å resolution, respective...

Crystal structure of product-bound complex of UDP-N-acetyl-d-mannosamine dehydrogenase from Pyrococcus horikoshii OT3.

Science.gov (United States)

Pampa, K J; Lokanath, N K; Girish, T U; Kunishima, N; Rai, V R

2014-10-24

UDP-N-acetyl-d-mannosamine dehydrogenase (UDP-d-ManNAcDH) belongs to UDP-glucose/GDP-mannose dehydrogenase family and catalyzes Uridine-diphospho-N-acetyl-d-mannosamine (UDP-d-ManNAc) to Uridine-diphospho-N-acetyl-d-mannosaminuronic acid (UDP-d-ManNAcA) through twofold oxidation of NAD(+). In order to reveal the structural features of the Pyrococcus horikoshii UDP-d-ManNAcADH, we have determined the crystal structure of the product-bound enzyme by X-ray diffraction to resolution of 1.55Å. The protomer folds into three distinct domains; nucleotide binding domain (NBD), substrate binding domain (SBD) and oligomerization domain (OD, involved in the dimerization). The clear electron density of the UDP-d-ManNAcA is observed and the residues binding are identified for the first time. Crystal structures reveal a tight dimeric polymer chains with product-bound in all the structures. The catalytic residues Cys258 and Lys204 are conserved. The Cys258 acts as catalytic nucleophile and Lys204 as acid/base catalyst. The product is directly interacts with residues Arg211, Thr249, Arg244, Gly255, Arg289, Lys319 and Arg398. In addition, the structural parameters responsible for thermostability and oligomerization of the three dimensional structure are analyzed. Copyright © 2014 Elsevier Inc. All rights reserved.

PHENOBARBITAL AFFECTS THYROID HISTOLOGY AND LARVAL DEVELOPMENT IN THE AFRICAN CLAWED FROG XENOPUS LAEVIS

Science.gov (United States)

The abstract highlights our recent study to explore endocrine disrupting effects of phenobarbital in the African clawed frog, Xenopus laevis. In mammals, this chemical is known to induce the biotransforming enzyme UDP-glucuronosyltransferase (UDPGT) resulting in increased thyroid...

Evaluation of 99mTc-Mercaptoacetyltriglycine-Biocytin as a new hepatobiliary imaging agent in mice coinjected with bilirubin

International Nuclear Information System (INIS)

Kim, Meyoung-kon; Seidel, Juergen; Le Nhat; Kim, In-Sook; Yoo, Tae-Moo; Barker, Craig; Kobayashi, Hisataka; Green, Michael V.; Carrasquillo, Jorge A.; Paik, Chang H.

1999-01-01

We evaluated 99m Tc-labeled mercaptoacetyltriglycine ( 99m Tc-MAG3)-biocytin as a hepatobiliary imaging agent in the absence and presence of bilirubin in mice. We then compared its pharmacokinetic parameters; peak liver/heart activity ratio (r max ) and half clearance time (HCT) with those of 99m Tc-labeled diisopropyl-iminodiacetic acid ( 99m Tc-disofenin). Balb/c mice were injected intravenously with hepatobiliary agent ( 99m Tc-MAG3-biocytin or 99m Tc-disofenin) alone or in combination with bilirubin at two doses (7 and 14 mg/kg) dissolved in 5% human serum albumin. Images were acquired every 15 s for 30 min with a gamma-camera equipped with a pinhole collimator. Dynamic images showed rapid hepatic uptake of 99m Tc-MAG3-biocytin, with rapid clearance from the blood and rapid excretion via the biliary system. Its hepatic uptake was not affected by bilirubin coinjection, whereas 99m Tc-disofenin coinjected with bilirubin showed a higher blood background than 99m Tc-disofenin alone. These qualitative findings were reflected in pharmacokinetic parameters, r max and HCT. The r max was obtained from plots of time versus liver/heart activity ratios obtained in equal-area regions of interest over the heart and liver. The HCT was calculated from the hepatic clearance curve from plots of time versus liver activity. 99m Tc-MAG3-biocytin without bilirubin coinjection showed an r max of 8.9±1.3 and an HCT of 399±36 s. These values did not change even when 14 mg/kg of bilirubin were coinjected. By contrast, the parameters for 99m Tc-disofenin with bilirubin were significantly (p max was decreased from 7.9±2.5 to 1.4±0.2 and HCT was increased from 292±32 s to 782±133 s. 99m Tc-MAG3-biocytin hepatobiliary scintigraphy in mice is not affected by bilirubin coinjection, and this hepatobiliary agent appears to offer promise for estimating hepatic function in patients with high bilirubin levels

Photoacoustic microscopy of bilirubin in tissue phantoms

Science.gov (United States)

Zhou, Yong; Zhang, Chi; Yao, Da-Kang; Wang, Lihong V.

2012-12-01

Determining both bilirubin's concentration and its spatial distribution are important in disease diagnosis. Here, for the first time, we applied quantitative multiwavelength photoacoustic microscopy (PAM) to detect bilirubin concentration and distribution simultaneously. By measuring tissue-mimicking phantoms with different bilirubin concentrations, we showed that the root-mean-square error of prediction has reached 0.52 and 0.83 mg/dL for pure bilirubin and for blood-mixed bilirubin detection (with 100% oxygen saturation), respectively. We further demonstrated the capability of the PAM system to image bilirubin distribution both with and without blood. Finally, by underlaying bilirubin phantoms with mouse skins, we showed that bilirubin can be imaged with consistent accuracy down to >400 μm in depth. Our results show that PAM has potential for noninvasive bilirubin monitoring in vivo, as well as for further clinical applications.

First animal experiments and clinical investigations with sup(99m)Tc-bilirubin

International Nuclear Information System (INIS)

Schneider, G.; Kaempfer, I.; Blottner, A.; Rogos, R.; Deckart, H.

1986-01-01

Labelling of bilirubin with sup(99m)Tc is described. The distribution and elimination of the labelled substance was investigated in mice, rabbits, dogs and pigs. Within 5 minutes p.i. the labelled substance accumulated in the liver and was eliminated within several hours. Comparative studies of 14 C bilirubin and 14 C sup(99m)Tc bilirubin showed identical distribution patterns. Clinial trials were conducted in 60 patients who received 0.0015 mg/kg i.v. (total dose, 60-80 MBq of sup(99m)Tc bilirubin -> 1.6 - 2.2 mCi). Images were obtained in the first 20 min p.i. as well as after 2 and 24 hours. To determine the blood clearance blood samples were taken in the first hours and activity curves were recorded over the cardiac and temporal regions. As elimination from the liver was slow, gall bladder and bile duct imaging was not successful before 1 to 3 hours p.i. The severity of liver damage can be established on the basis of blood clearance, onset of active liver uptake, elimination from the liver and 24 hours excretion in percent. Labelled bilirubin is a suitable material for morphologic and dynamic functional imaging of the liver (e.g. for SPECT studies). Incidents were absent throughout. (Author)

Extreme Bilirubin Levels as a Causal Risk Factor for Symptomatic Gallstone Disease

DEFF Research Database (Denmark)

Stender, Stefan; Frikke-Schmidt, Ruth; Nordestgaard, Børge G

2013-01-01

In individuals without blockage of their bile ducts, levels of plasma bilirubin likely reflect levels of biliary bilirubin; higher biliary bilirubin levels may increase the risk of gallstone disease.......In individuals without blockage of their bile ducts, levels of plasma bilirubin likely reflect levels of biliary bilirubin; higher biliary bilirubin levels may increase the risk of gallstone disease....

Molecular imprinting polymer with polyoxometalate/carbon nitride nanotubes for electrochemical recognition of bilirubin

International Nuclear Information System (INIS)

Yola, Mehmet Lütfi; Göde, Ceren; Atar, Necip

2017-01-01

Highlights: •Bilirubin-imprinted sensor is developed for the sensitive detection of bilirubin •The prepared based on nanocomposite were characterized by several methods. •Bilirubin-imprinted sensor offers the important advantages •Bilirubin-imprinted sensor is preferred to the other methods for analysis -- Abstract: In this work, a new molecular imprinted sensor based on polyoxometalate (H 3 PW 12 O 40 , POM) functionalized carbon nitride nanotubes (C 3 N 4 NTs) nanocomposite was prepared for bilirubin (BR) analysis. The structures of prepared surfaces based on the nanocomposite were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS) and energy dispersive x-ray analysis (EDX). After that, BR imprinted electrode on H 3 PW 12 O 40 /C 3 N 4 NTs nanocomposite was developed by cyclic voltammetry (CV) in 100 mM pyrrole containing 25 mM BR. The linearity range and the detection limit of the developed method were calculated as 1.0 × 10 −12 –1.0 × 10 −10 M and 3.0 × 10 −13 M, respectively. In addition, the imprinted sensor was applied to human plasma samples with high recovery and selectivity.

Electrochemical Sensor for Bilirubin Detection Using Screen Printed Electrodes Functionalized with Carbon Nanotubes and Graphene

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Madasamy Thangamuthu

2018-03-01

Full Text Available Practice oriented point-of-care diagnostics require easy-to-handle, miniaturized, and low-cost analytical tools. In a novel approach, screen printed carbon electrodes (SPEs, which were functionalized with nanomaterials, are employed for selective measurements of bilirubin, which is an important biomarker for jaundice. Multi-walled carbon nanotubes (MWCNT and graphene separately deposited on SPEs provide the core of an electrochemical sensor for bilirubin. The electrocatalytic activity towards bilirubin oxidation (bilirubin to biliverdin was observed at +0.25 V. In addition, a further peak corresponding to the electrochemical conversion of biliverdin into purpurin appeared at +0.48 V. When compared to MWCNT, the graphene type shows a 3-fold lower detection limit (0.3 ± 0.022 nM and 0.1 ± 0.018 nM, respectively, moreover, the graphene type exhibits a larger linear range (0.1–600 µM than MWCNT (0.5–500 µM with a two-fold better sensitivity, i.e., 30 nA µM−1 cm−2, and 15 nA µM−1 cm−2, respectively. The viability is validated through measurements of bilirubin in blood serum samples and the selectivity is ensured by inhibiting common interfering biological substrates using an ionic nafion membrane. The presented approach enables the design and implementation of low cost and miniaturized electrochemical sensors.

Electrochemical Sensor for Bilirubin Detection Using Screen Printed Electrodes Functionalized with Carbon Nanotubes and Graphene.

Science.gov (United States)

Thangamuthu, Madasamy; Gabriel, Willimann Eric; Santschi, Christian; Martin, Olivier J F

2018-03-07

Practice oriented point-of-care diagnostics require easy-to-handle, miniaturized, and low-cost analytical tools. In a novel approach, screen printed carbon electrodes (SPEs), which were functionalized with nanomaterials, are employed for selective measurements of bilirubin, which is an important biomarker for jaundice. Multi-walled carbon nanotubes (MWCNT) and graphene separately deposited on SPEs provide the core of an electrochemical sensor for bilirubin. The electrocatalytic activity towards bilirubin oxidation (bilirubin to biliverdin) was observed at +0.25 V. In addition, a further peak corresponding to the electrochemical conversion of biliverdin into purpurin appeared at +0.48 V. When compared to MWCNT, the graphene type shows a 3-fold lower detection limit (0.3 ± 0.022 nM and 0.1 ± 0.018 nM, respectively), moreover, the graphene type exhibits a larger linear range (0.1-600 µM) than MWCNT (0.5-500 µM) with a two-fold better sensitivity, i.e., 30 nA µM -1 cm -2 , and 15 nA µM -1 cm -2 , respectively. The viability is validated through measurements of bilirubin in blood serum samples and the selectivity is ensured by inhibiting common interfering biological substrates using an ionic nafion membrane. The presented approach enables the design and implementation of low cost and miniaturized electrochemical sensors.

Revalidation and rationale for high pKa values of unconjugated bilirubin

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Ostrow J Donald

2007-05-01

Full Text Available Abstract Background Our prior solvent partition analysis, published in 1992, yielded pKa values for unconjugated bilirubin of about 8.1 and 8.4, but these results have been challenged and studies by other methods have suggested pKa values below 5.0. Methods We repeated our published solvent partition studies, using 14C-unconjugated bilirubin highly purified by extraction of residual labeled impurities from CHCl3 into an aqueous buffer, pH 7.0. Partition ratios at six pH values from 5.0 to 9.0 were determined by radioassay and compared with our prior values obtained by diazo assay. Results At pH values ranging from 4.8 to 9.2, stable aqueous/chloroform 14C-partition ratios did not differ significantly from our published partition ratios based on diazo assay. Conclusion These results support the high pKa values of unconjugated bilirubin, above 8.0, derived from our earlier solvent partition study. In both studies, our measurements were based on the rapid analysis of clearly under-saturated solutions of highly-purified bilirubin over a wide pH range, using properly purified and preserved solvents. No previous direct estimate of the aqueous pKa values of unconjugated bilirubin meets all these preconditions. Three theoretical factors acting in combination, each related to the unique, extensive internal H-bonding of the -COOH groups, are proposed to support high pKa values of unconjugated bilirubin in water: a donation of an H-bond from the -OH moiety of the -COOH group, which is broken on ionization; b hindered solvation of the -COO- group after ionization; and c restricted rotation of the -COO- and -COOH groups. Our findings and rationale rebut methodological and theoretical criticisms leveled against our prior work. High pKa values for unconjugated bilirubin dictate that: a bilirubin diacid, which readily diffuses across membranes and can cause neurotoxicity, is the dominant unbound bilirubin species of unconjugated bilirubin in plasma at

Improving oral bioavailability of resveratrol by a UDP-glucuronosyltransferase inhibitory excipient-based self-microemulsion.

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Yang, Fei-Fei; Zhou, Jing; Hu, Xiao; Cong, Zhao-Qing; Liu, Chun-Yu; Pan, Rui-Le; Chang, Qi; Liu, Xin-Min; Liao, Yong-Hong

2018-03-01

Self-microemulsifying (SME) drug delivery system has been developed to increase oral bioavailabilities, and inhibitory excipients are capable of improving oral bioavailability by inhibiting enzyme mediated intestinal metabolism. However, the potential of enzyme inhibitory excipients containing SME in boosting resveratrol bioavailability remains largely uninvestigated. In this study, we set out to prepare SME-1 with UGT inhibitory excipients (excipients without inhibitory activities named SME-2 as control) to increase the bioavailability of RES by inhibiting intestinal metabolism. Results demonstrated that similar physicochemical properties such as size, polydistribution index and in vitro release, cellular uptake and permeability in Caco-2 cells as well as in vivo lymphatic distribution between inhibitory SME-1 and non-inhibitory SME-2 were observed. In vivo study demonstrated that the molar ratios of RES-G/RES were 7.25±0.48 and 5.06±2.42 for free drug and SME-2, respectively, and the molar ratio decreased to 0.36±0.10 in SME-1 group. Pharmacokinetic study confirmed that the inhibitory excipients containing SME demonstrated potential in increasing bioavailability of RES from 6.5% for the free RES and 12.9% for SME-2 to 76.1% in SME-1 through modulating the glucuronidation by UGT inhibitory excipients. Copyright © 2018 Elsevier B.V. All rights reserved.

Identification and partial characterization of a novel UDP-N-acetylenolpyruvoylglucosamine reductase/UDP-N-acetylmuramate:L-alanine ligase fusion enzyme from Verrucomicrobium spinosum DSM 4136T

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Kubra F Naqvi

2016-03-01

Full Text Available The enzymes involved in synthesizing the bacterial cell wall are attractive targets for the design of antibacterial compounds, since this pathway is essential for bacteria and is absent in animals, particularly humans. A survey of the genome of a bacterium that belongs to the phylum Verrucomicrobia, the closest free-living relative to bacteria from the Chlamydiales phylum, shows genetic evidence that Verrucomicrobium spinosum possesses a novel fusion open reading frame (ORF annotated by the locus tag (VspiD_010100018130. The ORF, which is predicted to encode the enzymes UDP-N-acetylenolpyruvoylglucosamine reductase (MurB and UDP-N-acetylmuramate:L-alanine ligase (MurC that are involved in the cytoplasmic steps of peptidoglycan biosynthesis, was cloned. In vivo analyses using functional complementation showed that the fusion gene was able to complement E. coli murB and murC temperature sensitive mutants. The purified recombinant fusion enzyme (MurB/CVs was shown to be endowed with UDP-N-acetylmuramate:L-alanine ligase activity. In vitro analyses demonstrated that the latter enzyme had a pH optimum of 9.0, a magnesium optimum of 10 mM and a temperature optimum of 44-46 oC. Its apparent Km values for ATP, UDP-MurNAc and L-alanine were 470, 90 and 25 µM, respectively. However, all attempts to demonstrate an in vitro UDP-N-acetylenolpyruvoylglucosamine reductase (MurB activity were unsuccessful. Lastly, Hidden Markov Model-based similarity search and phylogenetic analysis revealed that this fusion enzyme could only be identified in specific lineages within the Verrucomicrobia phylum.

Identification and Partial Characterization of a Novel UDP-N-Acetylenolpyruvoylglucosamine Reductase/UDP-N-Acetylmuramate:l-Alanine Ligase Fusion Enzyme from Verrucomicrobium spinosum DSM 4136(T).

Science.gov (United States)

Naqvi, Kubra F; Patin, Delphine; Wheatley, Matthew S; Savka, Michael A; Dobson, Renwick C J; Gan, Han Ming; Barreteau, Hélène; Blanot, Didier; Mengin-Lecreulx, Dominique; Hudson, André O

2016-01-01

The enzymes involved in synthesizing the bacterial cell wall are attractive targets for the design of antibacterial compounds, since this pathway is essential for bacteria and is absent in animals, particularly humans. A survey of the genome of a bacterium that belongs to the phylum Verrucomicrobia, the closest free-living relative to bacteria from the Chlamydiales phylum, shows genetic evidence that Verrucomicrobium spinosum possesses a novel fusion open reading frame (ORF) annotated by the locus tag (VspiD_010100018130). The ORF, which is predicted to encode the enzymes UDP-N-acetylenolpyruvoylglucosamine reductase (MurB) and UDP-N-acetylmuramate:l-alanine ligase (MurC) that are involved in the cytoplasmic steps of peptidoglycan biosynthesis, was cloned. In vivo analyses using functional complementation showed that the fusion gene was able to complement Escherichia coli murB and murC temperature sensitive mutants. The purified recombinant fusion enzyme (MurB/C Vs ) was shown to be endowed with UDP-N-acetylmuramate:l-alanine ligase activity. In vitro analyses demonstrated that the latter enzyme had a pH optimum of 9.0, a magnesium optimum of 10 mM and a temperature optimum of 44-46°C. Its apparent K m values for ATP, UDP-MurNAc, and l-alanine were 470, 90, and 25 μM, respectively. However, all attempts to demonstrate an in vitro UDP-N-acetylenolpyruvoylglucosamine reductase (MurB) activity were unsuccessful. Lastly, Hidden Markov Model-based similarity search and phylogenetic analysis revealed that this fusion enzyme could only be identified in specific lineages within the Verrucomicrobia phylum.

Identification and Partial Characterization of a Novel UDP-N-Acetylenolpyruvoylglucosamine Reductase/UDP-N-Acetylmuramate:l-Alanine Ligase Fusion Enzyme from Verrucomicrobium spinosum DSM 4136T

Science.gov (United States)

Naqvi, Kubra F.; Patin, Delphine; Wheatley, Matthew S.; Savka, Michael A.; Dobson, Renwick C. J.; Gan, Han Ming; Barreteau, Hélène; Blanot, Didier; Mengin-Lecreulx, Dominique; Hudson, André O.

2016-01-01

The enzymes involved in synthesizing the bacterial cell wall are attractive targets for the design of antibacterial compounds, since this pathway is essential for bacteria and is absent in animals, particularly humans. A survey of the genome of a bacterium that belongs to the phylum Verrucomicrobia, the closest free-living relative to bacteria from the Chlamydiales phylum, shows genetic evidence that Verrucomicrobium spinosum possesses a novel fusion open reading frame (ORF) annotated by the locus tag (VspiD_010100018130). The ORF, which is predicted to encode the enzymes UDP-N-acetylenolpyruvoylglucosamine reductase (MurB) and UDP-N-acetylmuramate:l-alanine ligase (MurC) that are involved in the cytoplasmic steps of peptidoglycan biosynthesis, was cloned. In vivo analyses using functional complementation showed that the fusion gene was able to complement Escherichia coli murB and murC temperature sensitive mutants. The purified recombinant fusion enzyme (MurB/CVs) was shown to be endowed with UDP-N-acetylmuramate:l-alanine ligase activity. In vitro analyses demonstrated that the latter enzyme had a pH optimum of 9.0, a magnesium optimum of 10 mM and a temperature optimum of 44–46°C. Its apparent Km values for ATP, UDP-MurNAc, and l-alanine were 470, 90, and 25 μM, respectively. However, all attempts to demonstrate an in vitro UDP-N-acetylenolpyruvoylglucosamine reductase (MurB) activity were unsuccessful. Lastly, Hidden Markov Model-based similarity search and phylogenetic analysis revealed that this fusion enzyme could only be identified in specific lineages within the Verrucomicrobia phylum. PMID:27047475

Molecular cloning of a novel glucuronokinase/putative pyrophosphorylase from zebrafish acting in an UDP-glucuronic acid salvage pathway.

Directory of Open Access Journals (Sweden)

Roman Gangl

Full Text Available In animals, the main precursor for glycosaminoglycan and furthermore proteoglycan biosynthesis, like hyaluronic acid, is UDP-glucuronic acid, which is synthesized via the nucleotide sugar oxidation pathway. Mutations in this pathway cause severe developmental defects (deficiency in the initiation of heart valve formation. In plants, UDP-glucuronic acid is synthesized via two independent pathways. Beside the nucleotide sugar oxidation pathway, a second minor route to UDP-glucuronic acid exist termed the myo-inositol oxygenation pathway. Within this myo-inositol is ring cleaved into glucuronic acid, which is subsequently converted to UDP-glucuronic acid by glucuronokinase and UDP-sugar pyrophosphorylase. Here we report on a similar, but bifunctional enzyme from zebrafish (Danio rerio which has glucuronokinase/putative pyrophosphorylase activity. The enzyme can convert glucuronic acid into UDP-glucuronic acid, required for completion of the alternative pathway to UDP-glucuronic acid via myo-inositol and thus establishes a so far unknown second route to UDP-glucuronic acid in animals. Glucuronokinase from zebrafish is a member of the GHMP-kinase superfamily having unique substrate specificity for glucuronic acid with a Km of 31 ± 8 µM and accepting ATP as the only phosphate donor (Km: 59 ± 9 µM. UDP-glucuronic acid pyrophosphorylase from zebrafish has homology to bacterial nucleotidyltransferases and requires UTP as nucleosid diphosphate donor. Genes for bifunctional glucuronokinase and putative UDP-glucuronic acid pyrophosphorylase are conserved among some groups of lower animals, including fishes, frogs, tunicates, and polychaeta, but are absent from mammals. The existence of a second pathway for UDP-glucuronic acid biosynthesis in zebrafish likely explains some previous contradictory finding in jekyll/ugdh zebrafish developmental mutants, which showed residual glycosaminoglycans and proteoglycans in knockout mutants of UDP

Comparison of the inhibition capability of oleanolic acid and ...

African Journals Online (AJOL)

Background: Human UDP-glucuronosyltransferases (UGTs) are important membrane proteins located in endoplasmic reticulum, and play important roles in metabolism of a variety of endogenous and exogenous compounds. Aims: To determine the influence of subtle difference in the structure of oleanolic acid and betulinic ...

Quantitative imaging of bilirubin by photoacoustic microscopy

Science.gov (United States)

Zhou, Yong; Zhang, Chi; Yao, Da-Kang; Wang, Lihong V.

2013-03-01

Noninvasive detection of both bilirubin concentration and its distribution is important for disease diagnosis. Here we implemented photoacoustic microscopy (PAM) to detect bilirubin distribution. We first demonstrate that our PAM system can measure the absorption spectra of bilirubin and blood. We also image bilirubin distributions in tissuemimicking samples, both without and with blood mixed. Our results show that PAM has the potential to quantitatively image bilirubin in vivo for clinical applications.

Bilirubin prevents acute DSS-induced colitis by inhibiting leukocyte infiltration and suppressing upregulation of inducible nitric oxide synthase.

Science.gov (United States)

Zucker, Stephen D; Vogel, Megan E; Kindel, Tammy L; Smith, Darcey L H; Idelman, Gila; Avissar, Uri; Kakarlapudi, Ganesh; Masnovi, Michelle E

2015-11-15

Bilirubin is thought to exert anti-inflammatory effects by inhibiting vascular cell adhesion molecule-1 (VCAM-1)-dependent leukocyte migration and by suppressing the expression of inducible nitric oxide synthase (iNOS). As VCAM-1 and iNOS are important mediators of tissue injury in the dextran sodium sulfate (DSS) murine model of inflammatory colitis, we examined whether bilirubin prevents colonic injury in DSS-treated mice. Male C57BL/6 mice were administered 2.5% DSS in the drinking water for 7 days, while simultaneously receiving intraperitoneal injections of bilirubin (30 mg/kg) or potassium phosphate vehicle. Disease activity was monitored, peripheral blood counts and serum nitrate levels were determined, and intestinal specimens were analyzed for histological injury, leukocyte infiltration, and iNOS expression. The effect of bilirubin on IL-5 production by HSB-2 cells and on Jurkat cell transendothelial migration also was determined. DSS-treated mice that simultaneously received bilirubin lost less body weight, had lower serum nitrate levels, and exhibited reduced disease severity than vehicle-treated animals. Concordantly, histopathological analyses revealed that bilirubin-treated mice manifested significantly less colonic injury, including reduced infiltration of eosinophils, lymphocytes, and monocytes, and diminished iNOS expression. Bilirubin administration also was associated with decreased eosinophil and monocyte infiltration into the small intestine, with a corresponding increase in peripheral blood eosinophilia. Bilirubin prevented Jurkat migration but did not alter IL-5 production. In conclusion, bilirubin prevents DSS-induced colitis by inhibiting the migration of leukocytes across the vascular endothelium and by suppressing iNOS expression. Copyright © 2015 the American Physiological Society.

Structural and Functional Analysis of Campylobacter jejuni PseG: a Udp-sugarhydrolase from the Pseudaminic Acid Biosynthetic Pathway

Energy Technology Data Exchange (ETDEWEB)

E Rangarajan; A Proteau; Q Cui; S Logan; Z Potetinova; D Whitfield; E Purisima; M Cygler; A Matte; et al.

2011-12-31

Flagella of the bacteria Helicobacter pylori and Campylobacter jejuni are important virulence determinants, whose proper assembly and function are dependent upon glycosylation at multiple positions by sialic acid-like sugars, such as 5,7-diacetamido-3,5,7,9-tetradeoxy-l-glycero-l-manno-nonulosonic acid (pseudaminic acid (Pse)). The fourth enzymatic step in the pseudaminic acid pathway, the hydrolysis of UDP-2,4-diacetamido-2,4,6-trideoxy-{beta}-l-altropyranose to generate 2,4-diacetamido-2,4,6-trideoxy-l-altropyranose, is performed by the nucleotide sugar hydrolase PseG. To better understand the molecular basis of the PseG catalytic reaction, we have determined the crystal structures of C. jejuni PseG in apo-form and as a complex with its UDP product at 1.8 and 1.85 {angstrom} resolution, respectively. In addition, molecular modeling was utilized to provide insight into the structure of the PseG-substrate complex. This modeling identifies a His{sup 17}-coordinated water molecule as the putative nucleophile and suggests the UDP-sugar substrate adopts a twist-boat conformation upon binding to PseG, enhancing the exposure of the anomeric bond cleaved and favoring inversion at C-1. Furthermore, based on these structures a series of amino acid substitution derivatives were constructed, altering residues within the active site, and each was kinetically characterized to examine its contribution to PseG catalysis. In conjunction with structural comparisons, the almost complete inactivation of the PseG H17F and H17L derivatives suggests that His{sup 17} functions as an active site base, thereby activating the nucleophilic water molecule for attack of the anomeric C-O bond of the UDP-sugar. As the PseG structure reveals similarity to those of glycosyltransferase family-28 members, in particular that of Escherichia coli MurG, these findings may also be of relevance for the mechanistic understanding of this important enzyme family.

Correlations between polymorphisms in the uridine diphosphate-glucuronosyltransferase 1A and C-C motif chemokine receptor 5 genes and infection with the hepatitis B virus in three ethnic groups in China.

Science.gov (United States)

Zhang, Chan; He, Yan; Shan, Ke-Ren; Tan, Kui; Zhang, Ting; Wang, Chan-Juan; Guan, Zhi-Zhong

2018-02-01

Objective To determine whether genetic polymorphisms in the uridine diphosphate-glucuronosyltransferase 1A ( UGT1A) and the C-C motif chemokine receptor 5 ( CCR5) genes are associated with hepatitis B virus (HBV) infection in Yi, Yao and Han ethnic groups in the Guizhou Province of China. Methods The study enrolled subjects with and without HBV infection. Whole blood was used for DNA genotyping using standard techniques. The study determined the frequencies of several polymorphic alleles ( UGT1A6 [rs2070959], UGT1A1 [rs8175347], CCR5-59029 [rs1799987] and CCR5Δ32 [rs333]) and then characterized their relationship with HBV infection. Results A total of 404 subjects were enrolled in the study: 138 from the Yao group, 101 from the Yi group and 165 from the Han group. There was a significant difference in the frequency of UGT1A1 rs8175347 polymorphisms among the three groups. The rates of 7TA carriers of UGT1A1 rs8175347 in all three groups were significantly higher than the other genotypes. Individuals with genotype AA of UGT1A6 rs2070959 in the Yi group had a higher risk for HBV infection than in the Yao and Han groups. The frequency of genotype GG in CCR5-59029 in the Yao group was significantly higher than in the Yi group. The genotypes of CCR5Δ32 were not associated with HBV infection. Conclusion These findings provide genetic and epidemiological evidence for an association of UGT1A and CCR5-59029 polymorphisms with HBV infection in Chinese Yi and Yao populations.

Bilirubin-Induced Neurotoxicity in the Preterm Neonate.

Science.gov (United States)

Watchko, Jon F

2016-06-01

Bilirubin-induced neurotoxicity in preterm neonates remains a clinical concern. Multiple cellular and molecular cascades likely underlie bilirubin-induced neuronal injury, including plasma membrane perturbations, excitotoxicity, neuroinflammation, oxidative stress, and cell cycle arrest. Preterm newborns are particularly vulnerable secondary to central nervous system immaturity and concurrent adverse clinical conditions that may potentiate bilirubin toxicity. Acute bilirubin encephalopathy in preterm neonates may be subtle and manifest primarily as recurrent symptomatic apneic events. Low-bilirubin kernicterus continues to be reported in preterm neonates, and although multifactorial in nature, is often associated with marked hypoalbuminemia. Copyright © 2016 Elsevier Inc. All rights reserved.

Higher Serum Direct Bilirubin Levels Were Associated with a Lower Risk of Incident Chronic Kidney Disease in Middle Aged Korean Men

Science.gov (United States)

Ryu, Seungho; Chang, Yoosoo; Zhang, Yiyi; Woo, Hee-Yeon; Kwon, Min-Jung; Park, Hyosoon; Lee, Kyu-Beck; Son, Hee Jung; Cho, Juhee; Guallar, Eliseo

2014-01-01

Background The association between serum bilirubin levels and incident chronic kidney disease (CKD) in the general population is unknown. We aimed to examine the association between serum bilirubin concentration (total, direct, and indirect) and the risk of incident CKD. Methods and Findings Longitudinal cohort study of 12,823 Korean male workers 30 to 59 years old without CKD or proteinuria at baseline participating in medical health checkup program in a large worksite. Study participants were followed for incident CKD from 2002 through 2011. Estimated glomerular filtration rate (eGFR) was estimated by using the CKD-EPI equation. CKD was defined as eGFR bilirubin were 0.93 (95% CI 0.67–1.28), 0.88 (0.60–1.27) and 0.60 (0.42–0.88), respectively. In multivariable models, the adjusted hazard ratio for CKD comparing the highest to the lowest quartile of serum direct bilirubin levels was 0.60 (95% CI 0.41–0.87; P trend = 0.01). Neither serum total nor indirect bilirubin levels were significantly associated with the incidence of CKD. Conclusions Higher serum direct bilirubin levels were significantly associated with a lower risk of developing CKD, even adjusting for a variety of cardiometabolic parameters. Further research is needed to elucidate the mechanisms underlying this association and to establish the role of serum direct bilirubin as a marker for CKD risk. PMID:24586219

Analysis of the polymerization initiation and activity of Pasteurella multocida heparosan synthase PmHS2, an enzyme with glycosyltransferase and UDP-sugar hydrolase activity

NARCIS (Netherlands)

Chavaroche, A.A.E.; Broek, van den L.A.M.; Springer, J.; Boeriu, C.; Eggink, G.

2011-01-01

Heparosan synthase catalyzes the polymerization of heparosan [-4GlcUAß1-4GlcNAca1-]n by transferring alternatively the monosaccharide units from UDP-GlcUA and UDP-GlcNAc to an acceptor molecule. Details on the heparosan chain initiation by Pasteurella multocida heparosan synthase PmHS2 and its

UDP ratios on intake and milk production efficiency in Saanen ewes

African Journals Online (AJOL)

Unknown

Feed intake was significantly influenced by the RDP: UDP ratio and the LD diet achieved a higher feed intake than the MD and HD diets. The HD diet has a better feed conversion efficiency largely due to a better utilisation of body reserves to complement available protein (Change in body Weight, Table 1). The milk ...

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

International Nuclear Information System (INIS)

Richardson, Terrilyn A.; Klaassen, Curtis D.

2010-01-01

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

Lightweight UDP Pervasive Protocol in Smart Home Environment Based on Labview

Science.gov (United States)

Kurniawan, Wijaya; Hannats Hanafi Ichsan, Mochammad; Rizqika Akbar, Sabriansyah; Arwani, Issa

2017-04-01

TCP (Transmission Control Protocol) technology in a reliable environment was not a problem, but not in an environment where the entire Smart Home network connected locally. Currently employing pervasive protocols using TCP technology, when data transmission is sent, it would be slower because they have to perform handshaking process in advance and could not broadcast the data. On smart home environment, it does not need large size and complex data transmission between monitoring site and monitoring center required in Smart home strain monitoring system. UDP (User Datagram Protocol) technology is quick and simple on data transmission process. UDP can broadcast messages because the UDP did not require handshaking and with more efficient memory usage. LabVIEW is a programming language software for processing and visualization of data in the field of data acquisition. This paper proposes to examine Pervasive UDP protocol implementations in smart home environment based on LabVIEW. UDP coded in LabVIEW and experiments were performed on a PC and can work properly.

Effects of UGT1A9 genetic polymorphisms on monohydroxylated derivative of oxcarbazepine concentrations and oxcarbazepine monotherapeutic efficacy in Chinese patients with epilepsy.

Science.gov (United States)

Lu, Yao; Fang, Youxin; Wu, Xunyi; Ma, Chunlai; Wang, Yue; Xu, Lan

2017-03-01

The human UDP-glucuronosyltransferase which is genetically polymorphic catalyzes glucuronidations of various drugs. The interactions among UGT1A4, UGT1A6, UGT1A9, and UGT2B15 genetic polymorphisms, monohydroxylated derivative (MHD) of oxcarbazepine (OXC) plasma concentrations, and OXC monotherapeutic efficacy were explored in 124 Chinese patients with epilepsy receiving OXC monotherapy. MHD is the major active metabolite of OXC, and its plasma concentration was measured using high-performance liquid chromatography when patients reached their maintenance dose of OXC. Genomic DNA was extracted from whole blood and SNP genotyping performed using PCR followed by dideoxy chain termination sequencing. We followed the patients for at least 1 year to evaluate the OXC monotherapy efficacy. Patients were divided into two groups according to their therapeutic outcome: group 1, seizure free; group 2, not seizure free. The data were analyzed using T test, one-way analysis of variance (ANOVA), Kruskal-Wallis test, chi-square test, Fisher's exact test, correlation analysis, and multivariate regression analysis. T test analysis showed that MHD plasma concentrations were significantly different between the two groups (p = 0.002). One-way ANOVA followed by Bonferroni post hoc testing of four candidate SNPs revealed that carriers of the UGT1A9 variant allele I399 C > T (TT 13.28 ± 7.44 mg/L, TC 16.41 ± 6.53 mg/L) had significantly lower MHD plasma concentrations and poorer seizure control than noncarriers (CC 22.24 ± 8.49 mg/L, p effects of UGT1A9 genetic polymorphisms on MHD plasma concentrations and OXC therapeutic efficacy. Through MHD monitoring, we can predict OXC therapeutic efficacy, which may be useful for the personalization of OXC therapy in epileptic patients.

Purification, crystallization and preliminary X-ray diffraction studies of a putative UDP-N-acetyl-d-mannosamine dehydrogenase from Pyrococcus horikoshii OT3

Energy Technology Data Exchange (ETDEWEB)

Lokanath, Neratur K.; Pampa, Kudigana J.; Kamiya, Toshimi; Kunishima, Naoki, E-mail: kunisima@spring8.or.jp [Advanced Protein Crystallography Research Group, RIKEN SPring-8 Center, Harima Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)

2007-05-01

A putative UDP-N-acetyl-d-mannosamine dehydrogenase from P. horikoshii OT3 has been crystallized in space group P2{sub 1}, with unit-cell parameters a = 80.28, b = 69.24, c = 83.10 Å, β = 114.4°. X-ray diffraction data have been collected to 1.80 Å resolution. A putative UDP-N-acetyl-d-mannosamine dehydrogenase from Pyrococcus horikoshii OT3, an essential enzyme for polysaccharide biosynthesis, has been overexpressed in Escherichia coli and purified. Crystals were obtained using the oil-microbatch method at 291 K. A native data set extending to 1.8 Å resolution has been collected and processed in space group P2{sub 1}. Assuming the presence of a dimer in the asymmetric unit, the V{sub M} value is calculated to be 2.3 Å{sup 3} Da{sup −1}, which is consistent with the result of a dynamic light-scattering experiment that shows a dimeric state of the protein in solution.

Studies on bile acid and bilirubin in liver diseases Part 2. Clinical significance of serum bilirubin sulfate in various liver diseases

OpenAIRE

石川, 泰祐

1980-01-01

The clinical significance of serum bilirubin sulfate, one of the direct bilirubin, was evaluated in various liver diseases with over 2 mg/dl of serum bilirubin concentration. The diagnosis included 25 cases of acute hepatitis, 8 cases of chronic hepatitis, 8 cases of liver cirrhosis and 16 cases of liver cirrhosis with hepatoma. Bilirubin sulfate was fractioned by Yonei's solvent partition method. The clinical significance of bilirubin sulfate was assessed by comparison of bilirubin sulfate w...

Enzymatic Removal of Bilirubin from Blood: A Potential Treatment for Neonatal Jaundice

Science.gov (United States)

Lavin, Arthur; Sung, Cynthia; Klibanov, Alexander M.; Langer, Robert

1985-11-01

Current treatments for severe jaundice can result in major complications. Neonatal jaundice is caused by excessive accumulation of bilirubin in the blood. A small blood filter containing immobilized bilirubin oxidase was developed to reduce serum bilirubin concentrations. When human or rat blood was passed through the enzyme filter, more than 90 percent of the bilirubin was degraded in a single pass. This procedure may have important applications in the clinical treatment of neonatal jaundice.

A green and facile approach for synthesizing imine to develop optical biosensor for wide range detection of bilirubin in human biofluids.

Science.gov (United States)

Ellairaja, Sundaram; Shenbagavalli, Kathiravan; Ponmariappan, Sarkaraisamy; Vasantha, Vairathevar Sivasamy

2017-05-15

Bilirubin, a key biomarker for the jaundice and its clinical diagnosis needs a better analytical tool. A novel and simple fluorescent platform based on (2,2'-((1E,1'E)-((6-bromopyridine-2,3-diyl) bis(azanylylidene)) bis(methanylylidene diphenol) (BAMD) was designed. BAMD showed a remarkable fluorescent intensity with a very good quantum yield of 0.85 and lifetime of 870ps. Hence, it was applied for the determination of bilirubin using both colorimetric and fluorimetric techniques in physiological and basic pH. Under optimized experimental conditions, the probe detects bilirubin selectively in the presence of other interfering biomolecules and metal ions. The linear range of detection is 1pM-500µM at pH=7.4 and LOD is 2.8 and 3.3 pM at pH=7.4 and 9.0, respectively, which were reported so far. The probe detects the bilirubin through FRET mechanism. The practical application of the probe was successfully tested in the human blood and urine samples. Based on all above advantages, this simple idea can be applied to design a simple clinical diagnostic tool for jaundice. Copyright © 2016. Published by Elsevier B.V.

Does bilirubin protect against developing diabetes mellitus?

Science.gov (United States)

Breimer, Lars H; Mikhailidis, Dimitri P

2016-01-01

After 25 years of evaluating bilirubin as a possible protective agent in neonatal and cardiovascular disease, interest has moved on to a exploring a possible protective role in diabetes mellitus (DM). This review finds conflicting prospective data for a protective relationship though there are retrospective, case-controlled data, that can only show association, which is not causality. Only prospective studies can show causality. Also, it would appear that the underlying biochemical assumptions do not readily translate from the animal to the human setting. Given that many factors impact on circulating bilirubin levels, it is not surprising that a clear-cut answer is not available; the jury is still out. Any relationship between DM and bilirubin might relate to intermediates in bilirubin metabolism, including relationships involving the genes for the enzymes participating in those steps. Nevertheless, the pursuit of bilirubin in disease causation is opening new avenues for research and if it is established that serum bilirubin can predict risks, much will have been achieved. The answer may have to come from molecular genetic analyses. Copyright © 2016 Elsevier Inc. All rights reserved.

Determination of the energetics of the UDP-glucose pyrophosphorylase reaction by positional isotope exchange inhibition

International Nuclear Information System (INIS)

Hester, L.S.; Raushel, F.M.

1987-01-01

A method has been developed for obtaining qualitative information about enzyme-catalyzed reactions by measuring the inhibitory effects of added substrates on positional isotope exchange rates. It has been demonstrated for ordered kinetic mechanisms that an increase in the concentration of the second substrate to add to the enzyme will result in a linear increase in the ratio of the chemical and positional isotope exchange rates. The slopes and intercepts from these plots can be used to determine the partitioning ratios of binary and ternary enzyme complexes. The method has been applied to the reaction catalyzed by UDP-glucose pyrophosphorylase. A positional isotope exchange reaction was measured within oxygen-18-labeled UTP as a function of variable glucose 1-phosphate concentration in the forward reaction. In the reverse reaction, a positional isotope exchange reaction was measured within oxygen-18-labeled UDP-glucose as a function of increasing pyrophosphate concentration. The results have been interpreted to indicate that the interconversion of the ternary central complexes is fast relative to product dissociation in either direction. In the forward direction, the release of UDP-glucose is slower than the release of pyrophosphate. The release of glucose 1-phosphate is slower than the release of UTP in the reverse reaction

Bilirubin Blood Test: MedlinePlus Lab Test Information

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... this page: https://medlineplus.gov/labtests/bilirubinbloodtest.html Bilirubin Blood Test To use the sharing features on this page, please enable JavaScript. What is a Bilirubin Blood Test? A bilirubin blood test measures the ...

Quantitative assessment of the multiple processes responsible for bilirubin homeostasis in health and disease

Directory of Open Access Journals (Sweden)

Levitt DG

2014-09-01

Full Text Available David G Levitt,1 Michael D Levitt2 1Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA; 2Research Service, Veterans Affairs Medical Center, Minneapolis, MN, USAAbstract: Serum bilirubin measurements are commonly obtained for the evaluation of ill patients and to screen for liver disease in routine physical exams. An enormous research effort has identified the multiple mechanisms involved in the production and metabolism of conjugated (CB and unconjugated bilirubin (UB. While the qualitative effects of these mechanisms are well understood, their expected quantitative influence on serum bilirubin homeostasis has received less attention. In this review, each of the steps involved in bilirubin production, metabolism, hepatic cell uptake, and excretion is quantitatively examined. We then attempt to predict the expected effect of normal and defective function on serum UB and CB levels in health and disease states including hemolysis, extra- and intrahepatic cholestasis, hepatocellular diseases (eg, cirrhosis, hepatitis, and various congenital defects in bilirubin conjugation and secretion (eg, Gilbert's, Dubin–Johnson, Crigler–Najjar, Rotor syndromes. Novel aspects of this review include: 1 quantitative estimates of the free and total UB and CB in the plasma, hepatocyte, and bile; 2 detailed discussion of the important implications of the recently recognized role of the hepatic OATP transporters in the maintenance of CB homeostasis; 3 discussion of the differences between the standard diazo assay versus chromatographic measurement of CB and UB; 4 pharmacokinetic implications of the extremely high-affinity albumin binding of UB; 5 role of the enterohepatic circulation in physiologic jaundice of newborn and fasting hyperbilirubinemia; and 6 insights concerning the clinical interpretation of bilirubin measurements.Keywords: liver, conjugation, diazo, albumin, Rotor

Albumin-Bilirubin and Platelet-Albumin-Bilirubin Grades Accurately Predict Overall Survival in High-Risk Patients Undergoing Conventional Transarterial Chemoembolization for Hepatocellular Carcinoma.

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Hansmann, Jan; Evers, Maximilian J; Bui, James T; Lokken, R Peter; Lipnik, Andrew J; Gaba, Ron C; Ray, Charles E

2017-09-01

To evaluate albumin-bilirubin (ALBI) and platelet-albumin-bilirubin (PALBI) grades in predicting overall survival in high-risk patients undergoing conventional transarterial chemoembolization for hepatocellular carcinoma (HCC). This single-center retrospective study included 180 high-risk patients (142 men, 59 y ± 9) between April 2007 and January 2015. Patients were considered high-risk based on laboratory abnormalities before the procedure (bilirubin > 2.0 mg/dL, albumin 1.2 mg/dL); presence of ascites, encephalopathy, portal vein thrombus, or transjugular intrahepatic portosystemic shunt; or Model for End-Stage Liver Disease score > 15. Serum albumin, bilirubin, and platelet values were used to determine ALBI and PALBI grades. Overall survival was stratified by ALBI and PALBI grades with substratification by Child-Pugh class (CPC) and Barcelona Liver Clinic Cancer (BCLC) stage using Kaplan-Meier analysis. C-index was used to determine discriminatory ability and survival prediction accuracy. Median survival for 79 ALBI grade 2 patients and 101 ALBI grade 3 patients was 20.3 and 10.7 months, respectively (P  .05). ALBI and PALBI grades are accurate survival metrics in high-risk patients undergoing conventional transarterial chemoembolization for HCC. Use of these scores allows for more refined survival stratification within CPC and BCLC stage. Copyright © 2017 SIR. Published by Elsevier Inc. All rights reserved.

Dimethyl ester of bilirubin exhibits anti-inflammatory activity through inhibition of secretory phospholipase A2, lipoxygenase and cyclooxygenase.

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Joshi, Vikram; Umashankara, M; Ramakrishnan, Chandrasekaran; Nanjaraj Urs, Ankanahalli N; Suvilesh, Kanve Nagaraj; Velmurugan, Devadasan; Rangappa, Kanchugarakoppal S; Vishwanath, Bannikuppe Sannanaik

2016-05-15

Overproduction of arachidonic acid (AA) mediated by secretory phospholipase A2 group IIA (sPLA2IIA) is a hallmark of many inflammatory disorders. AA is subsequently converted into pro-inflammatory eicosanoids through 5-lipoxygenase (5-LOX) and cyclooxygenase-1/2 (COX-1/2) activities. Hence, inhibition of sPLA2IIA, 5-LOX and COX-1/2 activities is critical in regulating inflammation. We have previously reported unconjugated bilirubin (UCB), an endogenous antioxidant, as sPLA2IIA inhibitor. However, lipophilic UCB gets conjugated in liver with glucuronic acid into hydrophilic conjugated bilirubin (CB). Since hydrophobicity is pre-requisite for sPLA2IIA inhibition, conjugation reduces the efficacy of UCB. In this regard, UCB was chemically modified and derivatives were evaluated for sPLA2IIA, 5-LOX and COX-1/2 inhibition. Among the derivatives, BD1 (dimethyl ester of bilirubin) exhibited ∼ 3 fold greater inhibitory potency towards sPLA2IIA compared to UCB. Both UCB and BD1 inhibited human 5-LOX and COX-2 activities; however only BD1 inhibited AA induced platelet aggregation. Molecular docking studies demonstrated BD1 as better inhibitor of aforesaid enzymes than UCB and other endogenous antioxidants. These data suggest that BD1 exhibits strong anti-inflammatory activity through inhibition of AA cascade enzymes which is of great therapeutic importance. Copyright © 2016 Elsevier Inc. All rights reserved.

Bacterial origin of a diverse family of UDP-glycosyltransferase genes in the Tetranychus urticae genome

NARCIS (Netherlands)

Ahn, S.J.; Dermauw, W.; Wybouw, N.; Heckel, D.G.; Van Leeuwen, T.

2014-01-01

UDP-glycosyltransferases (UGTs) catalyze the conjugation of a variety of small lipophilic molecules with uridine diphosphate (UDP) sugars, altering them into more water-soluble metabolites. Thereby, UGTs play an important role in the detoxification of xenobiotics and in the regulation of

Elucidation of substrate specificity in Aspergillus nidulans UDP-galactose-4-epimerase.

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Sean A Dalrymple

Full Text Available The frequency of invasive fungal infections has rapidly increased in recent years. Current clinical treatments are experiencing decreased potency due to severe host toxicity and the emergence of fungal drug resistance. As such, new targets and their corresponding synthetic pathways need to be explored for drug development purposes. In this context, galactofuranose residues, which are employed in fungal cell wall construction, but are notably absent in animals, represent an appealing target. Herein we present the structural and biochemical characterization of UDP-galactose-4-epimerase from Aspergillus nidulans which produces the precursor UDP-galactopyranose required for galactofuranose synthesis. Examination of the structural model revealed both NAD(+ and UDP-glucopyranose were bound within the active site cleft in a near identical fashion to that found in the Human epimerase. Mutational studies on the conserved catalytic motif support a similar mechanism to that established for the Human counterpart is likely operational within the A. nidulans epimerase. While the K m and k cat for the enzyme were determined to be 0.11 mM and 12.8 s(-1, respectively, a single point mutation, namely L320C, activated the enzyme towards larger N-acetylated substrates. Docking studies designed to probe active site affinity corroborate the experimentally determined activity profiles and support the kinetic inhibition results.

A cross-sectional study to evaluate second line virological failure and elevated bilirubin as a surrogate for adherence to atazanavir/ritonavir in two urban HIV clinics in Lilongwe, Malawi.

Science.gov (United States)

Ongubo, Dennis Miyoge; Lim, Robertino; Tweya, Hannock; Stanley, Christopher Chikhosi; Tembo, Petros; Broadhurst, Richard; Gugsa, Salem; Ngongondo, McNeil; Speight, Colin; Heller, Tom; Phiri, Sam; Hosseinipour, Mina C

2017-07-03

Malawi's national antiretroviral therapy program provides atazanavir/ritonavir-based second line regimens which cause concentration-dependent rise in indirect bilirubin. We sought to determine if elevated bilirubin, as a surrogate of atazanavir/ritonavir adherence, can aid in the evaluation of second line virological failure in Malawi. We conducted a cross-sectional study of HIV-infected patients ≥15 years who were on boosted protease inhibitor-based second line antiretroviral therapy for at least 6 months in two urban HIV clinics in Lilongwe, Malawi. Antiretroviral therapy history and adherence data were extracted from the electronic medical records and blood was drawn for viral load, complete blood count, total bilirubin, and CD4 cell count at a clinic visit. Factors associated with virological failure were assessed using multivariate logistic regression model. Out of 376 patients on second line antiretroviral therapy evaluated, 372 (98.9%) were on atazanavir/ritonavir-based therapy and 142 (37.8%) were male. Mean age was 40.9 years (SD ± 10.1), mean duration on second line antiretroviral therapy was 41.9 months (SD ± 27.6) and 256 patients (68.1%) had elevated bilirubin >1.3 mg/dL. Overall, 35 (9.3%) patients had viral load >1000 copies/ml (virological failure). Among the virologically failing vs. non-failing patients, bilirubin was elevated in 34.3% vs. 72.0% respectively (p bilirubin levels (aOR 5.4, p bilirubin levels better predicted virological failure than pill count adherence. Therefore, strategic use of bilirubin and viral load testing to target adherence counseling and support may be cost-effective in monitoring second line antiretroviral therapy adherence and virological failure. Drug resistance testing targeted for patients with virological failure despite elevated bilirubin levels would facilitate timely switch to third line antiretroviral regimens whenever available.

Serum bilirubin and the risk of rheumatoid arthritis.

Science.gov (United States)

Juping, Du; Yuan, Yuan; Shiyong, Chen; Jun, Li; Xiuxiu, Zhou; Haijian, Ying; Jianfeng, Shi; Bo, Shen

2017-11-01

Oxidative stress and immune imbalance play an important role in the pathogenesis of rheumatoid arthritis (RA). Bilirubin is a powerful antioxidant and also regarded as immunomodulator. Increased evidence shows that bilirubin should be a protective factor for autoimmune disease. However, the relationship between bilirubin and RA remain unclear. We analyzed serum bilirubin levels and other laboratory and clinical data in 130 RA patients (35 patients without any complications), 81 osteoarthritis (OA) patients and 96 healthy controls. Binary logistic regression adjusted by age and gender revealed that the levels of serum total, indirect bilirubin were significantly lower in RA patients, when compared with healthy controls (P=.015, OR=0.767, 95% CI=0.619-0.951; P=.010, OR=0.664, 95% CI=0.487-0.906, respectively) or OA patients (P=.000, OR=0.763, 95% CI=0.661-0.882; P=.000, OR=0.656, 95% CI=0.532-0.808, respectively). A reduced trend of levels of bilirubin has been detected along with increased disease activity, despite with no significance (P>.05). Spearman rank test further demonstrated that IgG and ESR were negative associated with total, indirect bilirubin, and albumin, prealbumin, APOA, HDL-C were positively associated with bilirubin. In conclusion, the levels of serum bilirubins were decreased in RA, and decreased levels could be associated with IgG, albumin and inflammatory marker ESR. © 2017 Wiley Periodicals, Inc.

Effect of honokiol on the induction of drug-metabolizing enzymes in human hepatocytes

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Cho YY

2014-11-01

Full Text Available Yong-Yeon Cho,1 Hyeon-Uk Jeong,1 Jeong-Han Kim,2 Hye Suk Lee1 1College of Pharmacy, The Catholic University of Korea, Bucheon, Korea; 2Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea Abstract: Honokiol, 2-(4-hydroxy-3-prop-2-enyl-phenyl-4-prop-2-enyl-phenol, an active component of Magnolia officinalis and Magnolia grandiflora, exerts various pharmacological activities such as antitumorigenic, antioxidative, anti-inflammatory, neurotrophic, and antithrombotic effects. To investigate whether honokiol acts as a perpetrator in drug interactions, messenger ribonucleic acid (mRNA levels of phase I and II drug-metabolizing enzymes, including cytochrome P450 (CYP, UDP-glucuronosyltransferase (UGT, and sulfotransferase 2A1 (SULT2A1, were analyzed by real-time reverse transcription polymerase chain reaction following 48-hour honokiol exposure in three independent cryopreserved human hepatocyte cultures. Honokiol treatment at the highest concentration tested (50 µM increased the CYP2B6 mRNA level and CYP2B6-catalyzed bupropion hydroxylase activity more than two-fold in three different hepatocyte cultures, indicating that honokiol induces CYP2B6 at higher concentrations. However, honokiol treatment (0.5–50 µM did not significantly alter the mRNA levels of phase I enzymes (CYP1A2, CYP3A4, CYP2C8, CYP2C9, and CYP2C19 or phase II enzymes (UGT1A1, UGT1A4, UGT1A9, UGT2B7, and SULT2A1 in cryopreserved human hepatocyte cultures. CYP1A2-catalyzed phenacetin O-deethylase and CYP3A4-catalyzed midazolam 1'-hydroxylase activities were not affected by 48-hour honokiol treatment in cryopreserved human hepatocytes. These results indicate that honokiol is a weak CYP2B6 inducer and is unlikely to increase the metabolism of concomitant CYP2B6 substrates and cause pharmacokinetic-based drug interactions in humans. Keywords: honokiol, human hepatocytes, drug interactions, cytochrome P450, UDP-glucuronosyltransferases

Independent and combined effect of bilirubin and smoking on the progression of chronic kidney disease

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Wang J

2018-01-01

Full Text Available Jiancheng Wang,1,* Binyan Wang,1,2,* Min Liang,1 Guobao Wang,1 Jianping Li,3 Yan Zhang,3 Yong Huo,3 Yimin Cui,4 Xiping Xu,1,5 Xianhui Qin1 1National Clinical Research Center for Kidney Disease, State Key Laboratory for Organ Failure Research, Renal Division, Nanfang Hospital, Southern Medical University, Guangzhou, 2Institute for Biomedicine, Anhui Medical University, Hefei, 3Department of Cardiology, 4Department of Pharmacy, Peking University First Hospital, Beijing, 5Beijing Advanced Innovation Center for Food Nutrition and Human Health, Key Laboratory of Functional Dairy, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China *These authors contributed equally to this work Objective: Whether serum bilirubin and cigarette smoking affect the risk of renal function decline remains inconclusive. We aimed to test the independent and combined effects of bilirubin and cigarette smoking on the progression of chronic kidney disease (CKD in hypertensive adults. Methods: The study population consisted of 12,633 patients in the renal sub-study of the China Stroke Primary Prevention Trial. The primary outcome was progression of CKD, defined as a decrease in estimated glomerular filtration rate (eGFR of ≥30% and to a level of <60 mL/min/1.73 m2 if baseline eGFR was ≥60 mL/min/1.73 m2, or a decrease in eGFR of ≥50% if baseline eGFR was <60 mL/min/1.73 m2, or end-stage renal disease. The secondary outcomes included 1 rapid decline in renal function and 2 annual rate of eGFR decline. Results: The median follow-up duration was 4.4 years. Cigarette smoking had no significant effect on the progression of CKD (odds ratio [OR]: 1.11, 95% confidence interval [95% CI]: 0.78–1.57. However, a significantly lower risk of the primary event (OR: 0.72, 95% CI: 0.55–0.95 was found in participants in tertile 3 compared to those in tertiles 1–2 for total bilirubin (TBiL levels. More importantly, there was an interaction

Stopped-flow studies of spectral changes in bilirubin-human serum albumin following an alkaline pH jump and following binding of bilirubin

DEFF Research Database (Denmark)

Honoré, B

1987-01-01

A stopped-flow technique was used to study the spectral changes occurring in bilirubin-albumin following a pH jump as well as following binding of bilirubin at 25 degrees C. The changes were studied in two wavelength ranges, 280-310 nm (tyrosine residues) and 400-510 nm (bound bilirubin). The cha......A stopped-flow technique was used to study the spectral changes occurring in bilirubin-albumin following a pH jump as well as following binding of bilirubin at 25 degrees C. The changes were studied in two wavelength ranges, 280-310 nm (tyrosine residues) and 400-510 nm (bound bilirubin......). The changes were analyzed according to a scheme of consecutive unimolecular reactions. Spectral monitoring of a pH jump from 11.3 to 11.8 reveals that the bilirubin-albumin complex changes its structure in several steps. The UV absorption spectra show that 3.8 tyrosine residues ionize in the first step, 2...

Laser Transcutaneous Bilirubin Meter: A New Device For Bilirubin Monitoring In Neonatal Jaundice

Science.gov (United States)

Hamza, Mostafa; Hamza, Mohammad

1988-06-01

Neonates with jaundice require monitoring of serum bilirubin which should be repeated at frequent intervals. However, taking blood samples from neonates is not always an easy job, plus being an invasive and traumatising procedure with the additional risk of blood loss. In this paper the authors present the theory and design of a new noninvasive device for transcutaneous bilirubinometry, using a differential absorption laser system. The new technique depends upon illuminating the skin of the neonate with radiation from a two wave-length oscillation laser. The choice of the wavelengths follows the principles of optical bilirubinometry. For obtaining more accurate measurements, different pairs of two wave-lengths are incorporated in the design. The presence of hemoglobin is corrected for by appropriate selection of the laser wavelengths. The new design was tested for accuracy and precision using an argon ion laser. Correlation study between serum bilirubin determination by laser transcutaneous bilirubinometry and by American optical bilirubinometer was highly significant.

Bilirubin-Induced Neurological Dysfunction: A Clinico-Radiological-Neurophysiological Correlation in 30 Consecutive Children.

Science.gov (United States)

van Toorn, Ronald; Brink, Philip; Smith, Johan; Ackermann, Christelle; Solomons, Regan

2016-12-01

The clinical expression of bilirubin-induced neurological dysfunction varies according to severity and location of the disease. Definitions have been proposed to describe different bilirubin-induced neurological dysfunction subtypes. Our objective was to describe the severity and clinico-radiological-neurophysiological correlation in 30 consecutive children with bilirubin-induced neurological dysfunction seen over a period of 5 years. Thirty children exposed to acute neonatal bilirubin encephalopathy were included in the study. The mean peak total serum bilirubin level was 625 μmol/L (range 480-900 μmol/L). Acoustic brainstem responses were abnormal in 73% (n = 22). Pallidal hyperintensity was observed on magnetic resonance imaging in 20 children. Peak total serum bilirubin levels correlated with motor severity (P = .03). Children with severe motor impairment were likely to manifest severe auditory neuropathy (P bilirubin-induced neurological dysfunction subtype, and the majority of children had abnormal acoustic brainstem responses and magnetic resonance imaging. © The Author(s) 2016.

Alteration of cell wall polysaccharides through transgenic expression of UDP-Glc 4-epimerase-encoding genes in potato tubers.

Science.gov (United States)

Huang, Jie-Hong; Kortstee, Anne; Dees, Dianka C T; Trindade, Luisa M; Schols, Henk A; Gruppen, Harry

2016-08-01

Uridine diphosphate (UDP)-glucose 4-epimerase (UGE) catalyzes the conversion of UDP-glucose to UDP-galactose. Cell wall materials from the cv. Kardal (wild-type, background) and two UGE transgenic lines (UGE 45-1 and UGE 51-16) were isolated and fractionated. The galactose (Gal) content (mg/100g tuber) from UGE 45-1 transgenic line was 38% higher than that of wild-type, and resulted in longer pectin side chains. The Gal content present in UGE 51-16 was 17% lower than that of wild-type, although most pectin populations maintained the same level of Gal. Both UGE transgenic lines showed unexpectedly a decrease in acetylation and an increase in methyl-esterification of pectin. Both UGE transgenic lines showed similar proportions of homogalacturonan and rhamnogalacturonan I within pectin backbone as the wild-type, except for the calcium-bound pectin fraction exhibiting relatively less rhamnogalacturonan I. Next to pectin modification, xyloglucan populations from both transgenic lines were altered resulting in different XSGG and XXGG proportion in comparison to wild-type. Copyright © 2016 Elsevier Ltd. All rights reserved.

Towards bilirubin imprinted poly(methacrylic acid-co-ethylene glycol dimethylacrylate) for the specific binding of α-bilirubin

International Nuclear Information System (INIS)

Syu, M.-J.; Deng, J.-H.; Nian, Y.-M.

2004-01-01

With α-bilirubin as a molecular template, polymerization of methacrylic acid (MAA) was carried out with the aid of the initiator 2,2-azobisisobutyronitrile (AIBN) and the cross-linking agent ethylene glycol dimethylacrylate (EGDMA). Bulk polymerization was successfully carried out so that poly(methacrylic acid-co-ethylene glycol dimethylacrylate) (poly(MAA-EGDMA)) imprinted with α-bilirubin was first developed. UV irradiation polymerization and heated polymerization methods were compared. Effect of different ratios of monomer to EGDMA during the polymerization was also discussed. Proper solvent for better desorption of α-bilirubin from the imprinted poly(MAA-EGDMA) was investigated. In addition, SEM photos were provided for observing the differences between the surfaces of the imprinted poly(MAA-EGDMA) before and after extraction. The corresponding binding results of α-bilirubin imprinted poly(MAA-EGDMA) and non-imprinted poly(MAA-EGDMA) both after extraction were compared. How the pH values during extraction stage affected the binding capacities of the imprinted polymer as well as non-imprinted polymer were also discussed. Similar study and comparison were made for different binding pH values. Different compounds of similar molecular weight were used to show the specific binding of the imprinted polymer for bilirubin. The results further confirmed the successful binding as well as specificity of the imprinted poly(MAA-EGDMA) for α-bilirubin

Oxidation reactions of bilirubin in aqueous solutions

International Nuclear Information System (INIS)

Mohan, Hari; Gopinathan, C.

1990-01-01

The radical cation of bilirubin (BR) has been tentatively identified as a transient intermediate in the reactions of BR with different oxidizing species such as Br 2 - , I 2 - and CH 3 I . OH. The rate constants for these reactions have been determined as 2.4 x 10 9 , l.0 x 10 9 and 2.7 x 10 9 dm 3 mol -1 s -1 , respectively. Biliverdin is likely to be among the stable products formed on oxidation of BR by these oxidizing species. (author)

Bilirubin and its oxidation products damage brain white matter

Science.gov (United States)

Lakovic, Katarina; Ai, Jinglu; D'Abbondanza, Josephine; Tariq, Asma; Sabri, Mohammed; Alarfaj, Abdullah K; Vasdev, Punarjot; Macdonald, Robert Loch

2014-01-01

Brain injury after intracerebral hemorrhage (ICH) occurs in cortex and white matter and may be mediated by blood breakdown products, including hemoglobin and heme. Effects of blood breakdown products, bilirubin and bilirubin oxidation products, have not been widely investigated in adult brain. Here, we first determined the effect of bilirubin and its oxidation products on the structure and function of white matter in vitro using brain slices. Subsequently, we determined whether these compounds have an effect on the structure and function of white matter in vivo. In all, 0.5 mmol/L bilirubin treatment significantly damaged both the function and the structure of myelinated axons but not the unmyelinated axons in brain slices. Toxicity of bilirubin in vitro was prevented by dimethyl sulfoxide. Bilirubin oxidation products (BOXes) may be responsible for the toxicity of bilirubin. In in vivo experiments, unmyelinated axons were found more susceptible to damage from bilirubin injection. These results suggest that unmyelinated axons may have a major role in white-matter damage in vivo. Since bilirubin and BOXes appear in a delayed manner after ICH, preventing their toxic effects may be worth investigating therapeutically. Dimethyl sulfoxide or its structurally related derivatives may have a potential therapeutic value at antagonizing axonal damage after hemorrhagic stroke. PMID:25160671

The effect of gamma-radiation on bilirubin

International Nuclear Information System (INIS)

Iqbal, M.S.; Shad, M.A.; Akhtar, M.I.

2001-01-01

The effect of gamma-radiations on bilirubin, in vitro, has been studied. It was found that gamma-radiation causes oxidation of bilirubin to biliverdine as one of the products. The likely implication of this effect in transformation of bilirubin to excretable products, in vino, in case of jaundice is discussed. (author)

Transport and metabolism at blood-brain interfaces and in neural cells: relevance to bilirubin-induced encephalopathy

Directory of Open Access Journals (Sweden)

Silvia eGazzin

2012-05-01

Full Text Available Bilirubin, the end-product of heme catabolism, circulates in non pathological plasma mostly as a protein-bound species. When bilirubin concentration builds up, the free fraction of the molecule increases. Unbound bilirubin then diffuses across blood-brain interfaces into the brain, where it accumulates and exerts neurotoxic effects. In this classical view of bilirubin neurotoxicity, blood-brain interfaces act merely as structural barriers impeding the penetration of the pigment-bound carrier protein, and neural cells are considered as passive targets of its toxicity. Yet, the role of blood-brain interfaces in the occurrence of bilirubin encephalopathy appears more complex than being simple barriers to the diffusion of bilirubin, and neural cells such as astrocytes and neurons can play an active role in controlling the balance between the neuroprotective and neurotoxic effects of bilirubin. This article reviews the emerging in vivo and in vitro data showing that transport and metabolic detoxification mechanisms at the blood-brain and blood-CSF barriers may modulate bilirubin flux across both cellular interfaces, and that these protective functions can be affected in chronic hyperbilirubinemia. Then the in vivo and in vitro arguments in favor of the physiological antioxidant function of intracerebral bilirubin are presented, as well as with the potential role of transporters such as ABCC-1 and metabolizing enzymes such as cytochromes P-450 in setting the cerebral cell- and structure-specific toxicity of bilirubin following hyperbilirubinemia. The relevance of these data to the pathophysiology of bilirubin-induced neurological diseases is discussed.

The UGT1A1*28 allele and disease in childhood

DEFF Research Database (Denmark)

Petersen, Jesper Padkær

2014-01-01

Baggrund: Bilirubin er slutproduktet i hæms metabolisme. Ukonjugeret bilirubin er neuro-toksisk, men også en potent antioxidant af mulig klinisk relevans. Fortolkningen af observationelle bilirubin studier vanskeliggøres af potentiel revers kausalitet og adskillige tænkelige confoundere. En måde ...

Bilirubin adsorption on nanocrystalline titania films

International Nuclear Information System (INIS)

Yang Zhengpeng; Si Shihui; Fung Yingsing

2007-01-01

Bilirubin produced from hemoglobin metabolism and normally conjugated with albumin is a kind of lipophilic endotoxin, and can cause various diseases when its concentration is high. Bilirubin adsorption on the nanocrystalline TiO 2 films was investigated using quartz crystal microbalance, UV-vis and IR techniques, and factors affecting its adsorption such as pH, bilirubin concentration, solution ionic strength, temperature and thickness of TiO 2 films were discussed. The amount of adsorption and parameters for the adsorption kinetics were estimated from the frequency measurements of quartz crystal microbalance. A fresh surface of the nanocrystalline TiO 2 films could be photochemically regenerated because holes and hydroxyl radicals were generated by irradiating the nanocrystalline TiO 2 films with UV light, which could oxidize and decompose organic materials, and the nanocrystalline TiO 2 films can be easily regenerated when it is used as adsorbent for the removal of bilirubin

Cells, bilirubin and light: formation of bilirubin photoproducts and cellular damage at defined wavelengths

International Nuclear Information System (INIS)

Christensen, T.; Kinn, G.; Granli, T.; Amundsen, I.

1994-01-01

Cultured cells from one human and one murine cell line were treated with bilirubin and irradiated with visible light of different wavelengths, either from phototherapy lamps or from a Xenon/Mercury lamp equipped with a monochromator. Bilirubin bound to human serum albumin was also irradiated with light. After irradiation, the bilirubin and its photoisomers were extracted with High Pressure Liquid Chromatography. The formation of single strand breaks in the DNA of treated cells was studied using a fluorescence marker. Cytotoxicity in the mouse skin cell line was measured by loss of the ability to form visible colonies in vitro. Green light exposure favours the production of lumirubin, while blue light causes more DNA damage and cytotoxicity. Green light may be more efficient and safer than shorter wavelength exposure when treating jaundiced newborns with phototherapy. 27 refs., 6 figs

Cloning, expression and characterization of a mammalian Nudix hydrolase-like enzyme that cleaves the pyrophosphate bond of UDP-glucose.

OpenAIRE

Yagi, Toshihiro; Baroja-Fernández, Edurne; Yamamoto, Ryuji; Muñoz, Francisco José; Akazawa, Takashi; Hong, Kyoung Su; Pozueta-Romero, Javier

2003-01-01

A distinct UDP-glucose (UDPG) pyrophosphatase (UGPPase, EC 3.6.1.45) has been characterized using pig kidney ( Sus scrofa ). This enzyme hydrolyses UDPG, the precursor molecule of numerous glycosylation reactions in animals, to produce glucose 1-phosphate (G1P) and UMP. Sequence analyses of the purified enzyme revealed that, similar to the case of a nucleotide-sugar hydrolase controlling the intracellular levels of ADP-glucose linked to glycogen biosynthesis in Escherichia coli [Moreno-Bruna,...

DECREASED BILIRUBIN TRANSPORT IN THE PERFUSED LIVER OF ENDOTOXEMIC RATS

NARCIS (Netherlands)

ROELOFSEN, H; VANDERVEERE, CN; OTTENHOFF, R; SCHOEMAKER, B; JANSEN, PLM; ELFERINK, RPJO

1994-01-01

Background/Aims: Hyperbilirubinemia associated with sepsis is frequently observed in humans. In this study, an experimental rat model was developed to study bilirubin metabolism and transport during endotoxemia. Methods: Rats were injected intravenously with a single bolus of lipopolysaccharide (1

Transcutaneous Bilirubin Nomogram for Healthy Term and Late Preterm Neonates in First 96 Hours of Life.

Science.gov (United States)

Thakkar, Pareshkumar; Chavda, Hardas; Doshi, Vikas

2017-05-15

To develop nomogram of Transcutaneous Bilirubin among healthy term and late-preterm neonates during first 96 hours of age. Longitudinal observational study. Neonatal unit of a tertiary care Hospital of Central Gujarat, India. 1075 healthy term and late preterm neonates (≥35weeks). Six-hourly transcutaneous bilirubin was obtained from birth to 96 hour of life using Drager JM 103 Transcutaneous Bilirubinometer. Main outcome measures: Nomogram of Transcutaneous Bilirubin with percentile values was obtained, rate of rise of bilirubin was calculated and predictive ability of normative data was analyzed for subsequent need of phototherapy. The age-specific percentile curves and nomogram were developed from the transcutaneous bilirubin readings of 1,010 neonates. Rate of rise in first 12 hour was 0.2 mg/dL and was 0.17 mg/dL in 12 to 24 hour of life which decreased on second day of life. Neonates who required phototherapy had consistently higher readings of transcutaneous bilirubin and also higher rate of rise in first 48 hrs. Neonates whose transcutaneous bilirubin is above the 50th percentile should be monitored for the development of significant hyperbilirubinemia.

Comparison of serum bilirubin estimation with transcutaneous bilirubinometry in neonates

International Nuclear Information System (INIS)

Waqar, T.; Ahmad, Z.; Ali, A.

2010-01-01

Objective: To assess usefulness of Minolta Air shield transcutaneous bilirubinometer by comparing bilirubin values obtained by transcutaneous jaundice meter with serum bilirubin estimation. Design: Analytical cross sectional study. Place and duration: NICU Military Hospital Rawalpindi Pakistan Jun 2002 to May 2005. Subjects and Methods: One hundred and fifty neonates admitted to NICU because of visible jaundice were included in the study. Serum was sent to laboratory for total bilirubin estimation. At the same time bilirubin was also checked by a Jaundice Meter. Data was tabulated and t-test applied to compare the two values. Results: One hundred and fifty paired estimations were performed. The transcutaneous bilirubin values ranged from 8.0 mg/dl to 20.4 mg/dl. While serum bilirubin by jaundice meter values ranged between 5.3 mg/dl and 26.0 mg/dl. A Scatter diagram was plotted. It showed a correlation coefficient of 0.78. Conclusion: Bilirubin values obtained by transcutaneous bilirubin meter were not significantly different from laboratory values thus proving the fact that transcutaneous bilirubinometer is a useful device to measure bilirubin. (author)

Bilirubin Increases Insulin Sensitivity in Leptin-Receptor Deficient and Diet-Induced Obese Mice Through Suppression of ER Stress and Chronic Inflammation

Science.gov (United States)

Dong, Huansheng; Huang, Hu; Yun, Xinxu; Kim, Do-sung; Yue, Yinan; Wu, Hongju; Sutter, Alton; Chavin, Kenneth D.; Otterbein, Leo E.; Adams, David B.; Kim, Young-Bum

2014-01-01

Obesity-induced endoplasmic reticulum (ER) stress causes chronic inflammation in adipose tissue and steatosis in the liver, and eventually leads to insulin resistance and type 2 diabetes (T2D). The goal of this study was to understand the mechanisms by which administration of bilirubin, a powerful antioxidant, reduces hyperglycemia and ameliorates obesity in leptin-receptor-deficient (db/db) and diet-induced obese (DIO) mouse models. db/db or DIO mice were injected with bilirubin or vehicle ip. Blood glucose and body weight were measured. Activation of insulin-signaling pathways, expression of inflammatory cytokines, and ER stress markers were measured in skeletal muscle, adipose tissue, and liver of mice. Bilirubin administration significantly reduced hyperglycemia and increased insulin sensitivity in db/db mice. Bilirubin treatment increased protein kinase B (PKB/Akt) phosphorylation in skeletal muscle and suppressed expression of ER stress markers, including the 78-kDa glucose-regulated protein (GRP78), CCAAT/enhancer-binding protein (C/EBP) homologous protein, X box binding protein (XBP-1), and activating transcription factor 4 in db/db mice. In DIO mice, bilirubin treatment significantly reduced body weight and increased insulin sensitivity. Moreover, bilirubin suppressed macrophage infiltration and proinflammatory cytokine expression, including TNF-α, IL-1β, and monocyte chemoattractant protein-1, in adipose tissue. In liver and adipose tissue of DIO mice, bilirubin ameliorated hepatic steatosis and reduced expression of GRP78 and C/EBP homologous protein. These results demonstrate that bilirubin administration improves hyperglycemia and obesity by increasing insulin sensitivity in both genetically engineered and DIO mice models. Bilirubin or bilirubin-increasing drugs might be useful as an insulin sensitizer for the treatment of obesity-induced insulin resistance and type 2 diabetes based on its profound anti-ER stress and antiinflammatory properties. PMID

Bilirubin bound to cells does not form photoisomers

International Nuclear Information System (INIS)

Christensen, T.; Kinn, G.

1993-01-01

Cultured cells from one human and one murine cell line were incubated with bilirubin by different methods that allowed bilirubin to be bound to cells. The cells were irradiated with visible light of different wavelengths. Bilirubin bound to human serum albumin was also irradiated with light. After irradiation, bilirubin and its photoisomers were extracted and analyzed by HPLC. No photoisomers were found in samples of irradiated cells, while the types and amounts of photoisomers that were expected from the literature were found in samples of irradiated bilirubin/albumin mixtures. It is concluded that the formation of therapeutically active photoisomers during phototherapy most probably does not take place in skin cells, but most likely in bilirubin bound to albumin in the vessels or in the interstitial space. 16 refs., 2 figs

Trans-Cutaneous Bilirubinometery versus Serum Bilirubin in Neonatal Jaundice.

Science.gov (United States)

Mahram, Manoochehr; Oveisi, Sonia; Jaberi, Najmeh

2015-12-01

Hyperbilirubinemia is a common problem in neonates and causes serious complications. Thus, serial measurements of bilirubin should be done. This assessment is done through two methods of laboratory measurement in serum sample and transcutaneous bilirubinometer. This descriptive study compared transcutaneous bilirubin assessment and laboratory serum bilirubin. Bilirubin level was assessed among 256 neonates admitted to the Qods Children's Hospital in Qazvin- Iran, because of neonatal indirect jaundice, through two methods of transcutaneous bilirubinometery from two sites of forehead and sternum and laboratory measurement of bilirubin in serum. The cases were non-hemolytic icteric term neonates weighing 2500 gram or more and had not received phototherapy or other treatments. Neonates with hemolytic forms of jaundice, sepsis and suspicious to metabolic disorders were excluded. Assessments by means of KJ-8000 transcutaneous bilirubinometer from two sites of forehead and sternum and through laboratory measurement of serum bilirubin were registered and analyzed. The results of the current study showed that there was a correlation of 0.82 between serum bilirubin and transcutaneous forehead bilirubin assessment and for the used device sensitivity of 0.844; specificity of 0.842, Youden Index of 0.709 and Shortest of 0.042 for a cut-off of 12.4 in bilirubin of participants. Furthermore, Likelihood Ratio positive and negative (LR) were 5.665 and 0.164, respectively and diagnostic Odds Ratio (LR+/LR-) was 34.56. Transcutaneous bilirubinometery can be considered as a reliable tool to assess bilirubin for the screening of neonatal jaundice in term neonates.

Improving UDP/IP Transmission Without Increasing Congestion

Science.gov (United States)

Burleigh, Scott

2006-01-01

Datagram Retransmission (DGR) is a computer program that, within certain limits, ensures the reception of each datagram transmitted under the User Datagram Protocol/Internet Protocol. [User Datagram Protocol (UDP) is considered unreliable because it does not involve a reliability-ensuring connection-initiation dialogue between sender and receiver. UDP is well suited to issuing of many small messages to many different receivers.] Unlike prior software for ensuring reception of UDP datagrams, DGR does not contribute to network congestion by retransmitting data more frequently as an ever-increasing number of messages and acknowledgements is lost. Instead, DGR does just the opposite: DGR includes an adaptive timeout-interval- computing component that provides maximum opportunity for reception of acknowledgements, minimizing retransmission. By monitoring changes in the rate at which message-transmission transactions are completed, DGR detects changes in the level of congestion and responds by imposing varying degrees of delay on the transmission of new messages. In addition, DGR maximizes throughput by not waiting for acknowledgement of a message before sending the next message. All DGR communication is asynchronous, to maximize efficient utilization of network connections. DGR manages multiple concurrent datagram transmission and acknowledgement conversations.

Dynamic Change of Total Bilirubin after Portal Vein Embolization is Predictive of Major Complications and Posthepatectomy Mortality in Patients with Hilar Cholangiocarcinoma.

Science.gov (United States)

Ou Yang, Qing; Zhang, Sheng; Cheng, Qing-Bao; Li, Bin; Feng, Fei-Ling; Yu, Yong; Luo, Xiang-Ji; Lin, Zhao-Fen; Jiang, Xiao-Qing

2016-05-01

This study aims to evaluate the role of dynamic change in total bilirubin after portal vein embolization (PVE) in predicting major complications and 30-day mortality in patients with hilar cholangiocarcinoma (HCCA). Retrospective analysis of prospectively maintained data of 64 HCCA patients who underwent PVE before hepatectomy in our institution was used. Total bilirubin and other parameters were measured daily in peri-PVE period. The difference between them and the baseline value from days 0-5 to day -1 (∆D1) and days 5-14 to day -1 (∆D2) were calculated. The relationship between ∆D1 and ∆D2 of total bilirubin and major complications as well as 30-day mortality was analyzed. Out of 64 patients, 10 developed major complications (15.6 %) and 6 patients (9.3 %) had died within 30 days after surgery. The ∆D2 of total bilirubin after PVE was most significantly associated with major complications (P 3 (OR = 12.048; 95 % CI 1.019-143.321), ∆D2 of total bilirubin (OR = 1.058; 95 % CI 1.007-1.112), and ∆D2 of prealbumin (OR = 0.975; 95 % CI 0.952-0.999) were associated with higher risk of 30-day mortality after PVE. Receiver operating characteristic curves showed that ∆D2 of total bilirubin were better predictors than ∆D1 for major complications (AUC (∆D2) 0.817; P = 0.002 vs. AUC (∆D1) 0.769; P = 0.007) and 30-day mortality (ACU(∆D2) 0.868; P = 0.003 vs. AUC(∆D1) 0.721;P = 0.076). Patients with increased total bilirubin in 5-14 days after PVE may indicate a higher risk of major complications and 30-day mortality if the major hepatectomy were performed.

Decreased bilirubin transport in the perfused liver of endotoxemic rats

NARCIS (Netherlands)

Roelofsen, H.; van der Veere, C. N.; Ottenhoff, R.; Schoemaker, B.; Jansen, P. L.; Oude Elferink, R. P.

1994-01-01

Hyperbilirubinemia associated with sepsis is frequently observed in humans. In this study, an experimental rat model was developed to study bilirubin metabolism and transport during endotoxemia. Rats were injected intravenously with a single bolus of lipopolysaccharide (1 mg/kg); after 18 hours, the

Hexosamines are unlikely to function as a nutrient-sensor in 3T3-L1 adipocytes: a comparison of UDP-hexosamine levels after increased glucose flux and glucosamine treatment.

NARCIS (Netherlands)

Bosch, R.R.; Pouwels, M.J.M.; Span, P.N.; Olthaar, A.J.; Tack, C.J.J.; Hermus, A.R.M.M.; Sweep, C.G.J.

2004-01-01

Whether the hexosamine biosynthesis pathway acts as a nutrient-sensing pathway is still unclear. Glucose is directed into this pathway by GFAT. Because the activity of GFAT is tightly regulated, we examined whether UDP-hexosamine levels can increase significantly and dose-dependently in response to

UDP-galactose: ceramide galactosyltransferase is a class I integral membrane protein of the endoplasmic reticulum

NARCIS (Netherlands)

Sprong, H.; Kruithof, B.; Leijendekker, R.L.; Slot, J.W.; van Meer, G.; van der Sluijs, P.

1998-01-01

UDP-galactose:ceramide galactosyltransferase (CGalT) transfers UDP-galactose to ceramide to form the glycosphingolipid galactosylceramide. Galactosylceramide is the major constituent of myelin and is also highly enriched in many epithelial cells, where it is thought to play an important role in

Mildly elevated serum total bilirubin levels are negatively associated with carotid atherosclerosis among elderly persons with type 2 diabetes.

Science.gov (United States)

Kawamoto, Ryuichi; Ninomiya, Daisuke; Hasegawa, Yoichi; Kasai, Yoshihisa; Kusunoki, Tomo; Ohtsuka, Nobuyuki; Kumagi, Teru; Abe, Masanori

2016-01-01

Diabetes is strongly associated with several mechanisms of tissue damage such as oxidative stress. Serum bilirubin may have a beneficial role in preventing oxidative changes in cardiovascular disease (CVD). Limited information is available on whether serum bilirubin is an independent confounding factor for carotid atherosclerosis among elderly persons with type 2 diabetes. The study subjects were 169 men aged 79 ± 8 (mean ± SD) years and 205 women aged 81 ± 8 years that were enrolled consecutively from patients in the medical department. Carotid intima-media thickness (IMT) and plaque were derived via B-mode ultrasonography. Multiple linear regression analysis showed that serum total bilirubin (β = -0.160) was significantly associated with carotid IMT. Compared to subjects with a serum total bilirubin of tertile-1 (0.13-0.58 mg/dL), the multivariate-adjusted odds ratio (95% confidence interval) of carotid IMT ≥1.0 mm including plaque and carotid plaque was 0.46 (0.23-0.93) and 0.32 (0.17-0.60) in the Tertile-3 group (0.87-1.93 mg/dL), respectively. Next, data were further stratified by gender, age, smoking status, medication and prevalence of CVD. There were no significant differences in serum total bilirubin levels between selected subgroups. Our data demonstrated a negative association between serum total bilirubin and carotid atherosclerosis among elderly persons with type 2 diabetes.

Activity-Based Profiling of a Physiologic Aglycone Library Reveals Sugar Acceptor Promiscuity of Family 1 UDP-Glucosyltransferases from Grape1[W

Science.gov (United States)

Bönisch, Friedericke; Frotscher, Johanna; Stanitzek, Sarah; Rühl, Ernst; Wüst, Matthias; Bitz, Oliver; Schwab, Wilfried

2014-01-01

Monoterpenols serve various biological functions and accumulate in grape (Vitis vinifera), where a major fraction occurs as nonvolatile glycosides. We have screened the grape genome for sequences with similarity to terpene URIDINE DIPHOSPHATE GLYCOSYLTRANSFERASES (UGTs) from Arabidopsis (Arabidopsis thaliana). A ripening-related expression pattern was shown for three candidates by spatial and temporal expression analyses in five grape cultivars. Transcript accumulation correlated with the production of monoterpenyl β-d-glucosides in grape exocarp during ripening and was low in vegetative tissue. Targeted functional screening of the recombinant UGTs for their biological substrates was performed by activity-based metabolite profiling (ABMP) employing a physiologic library of aglycones built from glycosides isolated from grape. This approach led to the identification of two UDP-glucose:monoterpenol β-d-glucosyltransferases. Whereas VvGT14a glucosylated geraniol, R,S-citronellol, and nerol with similar efficiency, the three allelic forms VvGT15a, VvGT15b, and VvGT15c preferred geraniol over nerol. Kinetic resolution of R,S-citronellol and R,S-linalool was shown for VvGT15a and VvGT14a, respectively. ABMP revealed geraniol as the major biological substrate but also disclosed that these UGTs may add to the production of further glycoconjugates in planta. ABMP of aglycone libraries provides a versatile tool to uncover novel biologically relevant substrates of small-molecule glycosyltransferases that often show broad sugar acceptor promiscuity. PMID:25073706

Mitochondrial targeting of bilirubin regulatory enzymes: An adaptive response to oxidative stress

Energy Technology Data Exchange (ETDEWEB)

Muhsain, Siti Nur Fadzilah, E-mail: sitinurfadzilah077@ppinang.uitm.edu.my [The University of Queensland, National Research Centre for Environmental Toxicology (Entox), 4072 Brisbane, Queensland (Australia); Faculty of Pharmacy, University Teknologi Mara (Malaysia); Lang, Matti A., E-mail: m.lang@uq.edu.au [The University of Queensland, National Research Centre for Environmental Toxicology (Entox), 4072 Brisbane, Queensland (Australia); Abu-Bakar, A' edah, E-mail: a.abubakar@uq.edu.au [The University of Queensland, National Research Centre for Environmental Toxicology (Entox), 4072 Brisbane, Queensland (Australia)

2015-01-01

The intracellular level of bilirubin (BR), an endogenous antioxidant that is cytotoxic at high concentrations, is tightly controlled within the optimal therapeutic range. We have recently described a concerted intracellular BR regulation by two microsomal enzymes: heme oxygenase 1 (HMOX1), essential for BR production and cytochrome P450 2A5 (CYP2A5), a BR oxidase. Herein, we describe targeting of these enzymes to hepatic mitochondria during oxidative stress. The kinetics of microsomal and mitochondrial BR oxidation were compared. Treatment of DBA/2J mice with 200 mg pyrazole/kg/day for 3 days increased hepatic intracellular protein carbonyl content and induced nucleo-translocation of Nrf2. HMOX1 and CYP2A5 proteins and activities were elevated in microsomes and mitoplasts but not the UGT1A1, a catalyst of BR glucuronidation. A CYP2A5 antibody inhibited 75% of microsomal BR oxidation. The inhibition was absent in control mitoplasts but elevated to 50% after treatment. An adrenodoxin reductase antibody did not inhibit microsomal BR oxidation but inhibited 50% of mitochondrial BR oxidation. Ascorbic acid inhibited 5% and 22% of the reaction in control and treated microsomes, respectively. In control mitoplasts the inhibition was 100%, which was reduced to 50% after treatment. Bilirubin affinity to mitochondrial and microsomal CYP2A5 enzyme is equally high. Lastly, the treatment neither released cytochrome c into cytoplasm nor dissipated membrane potential, indicating the absence of mitochondrial membrane damage. Collectively, the observations suggest that BR regulatory enzymes are recruited to mitochondria during oxidative stress and BR oxidation by mitochondrial CYP2A5 is supported by mitochondrial mono-oxygenase system. The induced recruitment potentially confers membrane protection. - Highlights: • Pyrazole induces oxidative stress in the mouse liver. • Pyrazole-induced oxidative stress induces mitochondrial targeting of key bilirubin regulatory enzymes, HMOX1

Mitochondrial targeting of bilirubin regulatory enzymes: An adaptive response to oxidative stress

International Nuclear Information System (INIS)

Muhsain, Siti Nur Fadzilah; Lang, Matti A.; Abu-Bakar, A'edah

2015-01-01

The intracellular level of bilirubin (BR), an endogenous antioxidant that is cytotoxic at high concentrations, is tightly controlled within the optimal therapeutic range. We have recently described a concerted intracellular BR regulation by two microsomal enzymes: heme oxygenase 1 (HMOX1), essential for BR production and cytochrome P450 2A5 (CYP2A5), a BR oxidase. Herein, we describe targeting of these enzymes to hepatic mitochondria during oxidative stress. The kinetics of microsomal and mitochondrial BR oxidation were compared. Treatment of DBA/2J mice with 200 mg pyrazole/kg/day for 3 days increased hepatic intracellular protein carbonyl content and induced nucleo-translocation of Nrf2. HMOX1 and CYP2A5 proteins and activities were elevated in microsomes and mitoplasts but not the UGT1A1, a catalyst of BR glucuronidation. A CYP2A5 antibody inhibited 75% of microsomal BR oxidation. The inhibition was absent in control mitoplasts but elevated to 50% after treatment. An adrenodoxin reductase antibody did not inhibit microsomal BR oxidation but inhibited 50% of mitochondrial BR oxidation. Ascorbic acid inhibited 5% and 22% of the reaction in control and treated microsomes, respectively. In control mitoplasts the inhibition was 100%, which was reduced to 50% after treatment. Bilirubin affinity to mitochondrial and microsomal CYP2A5 enzyme is equally high. Lastly, the treatment neither released cytochrome c into cytoplasm nor dissipated membrane potential, indicating the absence of mitochondrial membrane damage. Collectively, the observations suggest that BR regulatory enzymes are recruited to mitochondria during oxidative stress and BR oxidation by mitochondrial CYP2A5 is supported by mitochondrial mono-oxygenase system. The induced recruitment potentially confers membrane protection. - Highlights: • Pyrazole induces oxidative stress in the mouse liver. • Pyrazole-induced oxidative stress induces mitochondrial targeting of key bilirubin regulatory enzymes, HMOX1

Amine-functionalized PVA-co-PE nanofibrous membrane as affinity membrane with high adsorption capacity for bilirubin.

Science.gov (United States)

Wang, Wenwen; Zhang, Hao; Zhang, Zhifeng; Luo, Mengying; Wang, Yuedan; Liu, Qiongzhen; Chen, Yuanli; Li, Mufang; Wang, Dong

2017-02-01

In this study, poly(vinyl alcohol-co-ethylene) (PVA-co-PE) nanofibrous membrane was activated by sodium hydroxide and cyanuric chloride, and then the activated membranes were functionalized by 1,3-propanediamine, hexamethylenediamine and diethylenetriamine to be affinity membranes for bilirubin removal, respectively. The chemical structures and morphologies of membranes were investigated by SEM, FTIR and XPS. And the adsorption ability of different amine-functionalized nanofibrous membranes for bilirubin was characterized. Furthermore, the effects of temperature, initial concentration of bilirubin, NaCl concentration and BSA concentration on the adsorption capacity for bilirubin of diethylenetriamine-functionalized nanofibrous membrane were studied. Results indicated that the adsorption capacity for bilirubin of diethylenetriamine-functionalized nanofibrous membrane could reach 85mg/g membrane when the initial bilirubin concentration was 200mg/L while the adsorption capacity could be increased to 110mg/g membrane if the initial bilirubin concentration was more than 400mg/L. The dynamic adsorption of diethylenetriamine-functionalized nanofibrous membrane showed that the ligands of amine groups on the membrane surface could be used as far as possible by recirculating the plasma with certain flow rates. Therefore, the diethylenetriamine-functionalized PVA-co-PE nanofibrous membrane possessed high adsorption capacity for bilirubin and it can be candidate as affinity membrane for bilirubin removal. Copyright © 2016. Published by Elsevier B.V.

Bilirubin Modulates Acetylcholine Receptors In Rat Superior Cervical Ganglionic Neurons In a Bidirectional Manner

Science.gov (United States)

Zhang, Chengmi; Wang, Zhenmeng; Dong, Jing; Pan, Ruirui; Qiu, Haibo; Zhang, Jinmin; Zhang, Peng; Zheng, Jijian; Yu, Weifeng

2014-01-01

Autonomic dysfunction as a partial contributing factor to cardiovascular instability in jaundiced patients is often associated with increased serum bilirubin levels. Whether increased serum bilirubin levels could directly inhibit sympathetic ganglion transmission by blocking neuronal nicotinic acetylcholine receptors (nAChRs) remains to be elucidated. Conventional patch-clamp recordings were used to study the effect of bilirubin on nAChRs currents from enzymatically dissociated rat superior cervical ganglia (SCG) neurons. The results showed that low concnetrations (0.5 and 2 μM) of bilirubin enhanced the peak ACh-evoked currents, while high concentrations (3 to 5.5 µM) of bilirubin suppressed the currents with an IC50 of 4 ± 0.5 μM. In addition, bilirubin decreased the extent of desensitization of nAChRs in a concentration-dependent manner. This inhibitory effect of bilirubin on nAChRs channel currents was non-competitive and voltage independent. Bilirubin partly improved the inhibitory effect of forskolin on ACh-induced currents without affecting the action of H-89. These data suggest that the dual effects of enhancement and suppression of bilirubin on nAChR function may be ascribed to the action mechanism of positive allosteric modulation and direct blockade. Thus, suppression of sympathetic ganglionic transmission through postganglionic nAChRs inhibition may partially contribute to the adverse cardiovascular effects in jaundiced patients. PMID:25503810

Hepatocyte cotransport of taurocholate and bilirubin glucuronides: Role of microtubules

International Nuclear Information System (INIS)

Crawford, J.M.; Gollan, J.L.

1988-01-01

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 [ 14 C]bilirubin-[ 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 [ 14 C]bilirubin monoglucuronide-[ 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

A UDP-Glucose:Monoterpenol Glucosyltransferase Adds to the Chemical Diversity of the Grapevine Metabolome1[W

Science.gov (United States)

Bönisch, Friedericke; Frotscher, Johanna; Stanitzek, Sarah; Rühl, Ernst; Wüst, Matthias; Bitz, Oliver; Schwab, Wilfried

2014-01-01

Terpenoids represent one of the major classes of natural products and serve different biological functions. In grape (Vitis vinifera), a large fraction of these compounds is present as nonvolatile terpene glycosides. We have extracted putative glycosyltransferase (GT) sequences from the grape genome database that show similarity to Arabidopsis (Arabidopsis thaliana) GTs whose encoded proteins glucosylate a diversity of terpenes. Spatial and temporal expression levels of the potential VvGT genes were determined in five different grapevine varieties. Heterologous expression and biochemical assays of candidate genes led to the identification of a UDP-glucose:monoterpenol β-d-glucosyltransferase (VvGT7). The VvGT7 gene was expressed in various tissues in accordance with monoterpenyl glucoside accumulation in grape cultivars. Twelve allelic VvGT7 genes were isolated from five cultivars, and their encoded proteins were biochemically analyzed. They varied in substrate preference and catalytic activity. Three amino acids, which corresponded to none of the determinants previously identified for other plant GTs, were found to be important for enzymatic catalysis. Site-specific mutagenesis along with the analysis of allelic proteins also revealed amino acids that impact catalytic activity and substrate tolerance. These results demonstrate that VvGT7 may contribute to the production of geranyl and neryl glucoside during grape ripening. PMID:24784757

21 CFR 862.1110 - Bilirubin (total or direct) test system.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bilirubin (total or direct) test system. 862.1110... Systems § 862.1110 Bilirubin (total or direct) test system. (a) Identification. A bilirubin (total or direct) test system is a device intended to measure the levels of bilirubin (total or direct) in plasma...

Thermodynamic studies of bilirubin/cholesterol mixtures at the air/water interface

International Nuclear Information System (INIS)

Xie Anjian; Shen Yuhua; Xia Bing; Chen Hongbo; Ouyang Jianming

2005-01-01

Mixed monolayers of cholesterol and bilirubin spread at the air/water interface were used as model systems to examine the cholesterol effect on bilirubin. Miscibility and interactions between cholesterol and bilirubin were studied based on the analysis of the surface pressure-molecular area isotherms. From the isotherm data differentiated with respect to area, the condensing effect of cholesterol on the mixed monolayers could be observed distinctly. By studying surface compressibility modulus of bilirubin/cholesterol binary system vs. molecule area, we show that the liquid expanded-condensed phase transition (LE-C) of bilirubin was eliminated by cholesterol. In monolayers, bilirubin and cholesterol were found to be miscible at low surface pressure and immiscible at high surface pressure by studying the excess molecular areas of bilirubin/cholesterol system vs. mole fraction of bilirubin. The results from excess free energy of bilirubin/cholesterol system vs. mole fraction of bilirubin (X BR ) show that the maximum negative value of ΔG exc appeared at X BR =0.6, which indicates the formation of a bilirubin/cholesterol complex (M B-C ) of 3:2 stoichiometry as a result of the strong hydrogen bond between the polar groups of cholesterol and bilirubin and the self-assembly characteristics of cholesterol

Supramolecular Complexes Formed in Systems Bile Salt-Bilirubin-Silica

Science.gov (United States)

Vlasova, N. N.; Severinovskaya, O. V.; Golovkova, L. P.

The formation of supramolecular complexes between bilirubin and primary micelles of bile salts has been studied. The association constants of bile salts and binding of bilirubin with these associates have been determined. The adsorption of bilirubin and bile salts from individual and mixed aqueous solutions onto hydrophobic silica surfaces has been investigated. The interaction of bilirubin with primary bile salt micelles and the strong retention in mixed micelles, which are supramolecular complexes, result in the adsorption of bilirubin in free state only.

Predictors of the change in bilirubin levels over twelve weeks of treatment with atazanavir

LENUS (Irish Health Repository)

Cotter, Aoife G

2013-05-16

AbstractObjectiveTo determine the factors associated with change in bilirubin concentration 12 weeks after the initiation of an atazanavir (ATV)-containing antiretroviral regimen.MethodsWe performed a retrospective case note review of all patients prescribed ATV between January 2004 and October 2007 in a cohort of HIV infected subjects. Data collected included baseline demographics, hepatitis B and C serology, current antiretroviral therapy, baseline and week 12 routine bloods. The primary endpoint was the change in bilirubin concentration at 12 weeks after start of ATV. Multvariable linear regression was performed to assess the relationships between the change in bilirubin and variables of interest. Results: Eighty-three ATV-treated patients were included in the analysis of whom 46 (60.5%) were hepatitis C antibody positive. The median (interquartile range) change in bilirubin by week 12 was 16 (4, 22) umol\\/L; only 1 patient developed grade 4 hyperbilirubinaemia at week 12. After controlling for baseline bilirubin levels, HCV seropositivity and baseline ALP were associated with a smaller change in bilirubin over the 12 weeks with a trend towards lower increases in those receiving tenofovir. Sensitivity analyses reported similar associations with methadone use and injection drug use, when these variables replaced HCV sero-positivity in the model. Conclusion: Patients with hepatitis C co-infection experience smaller changes in bilirubin upon exposure to ATV. Although the underlying mechanism for this association remains unclear, these data support the safe use of this drug in this patient setting. Further research into the clinical predictors of ATV-related hyperbilirubinaemia is warranted.

A Novel Newborn Rat Kernicterus Model Created by Injecting a Bilirubin Solution into the Cisterna Magna

Science.gov (United States)

Song, Sijie; Hu, Ying; Gu, Xianfang; Si, Feifei; Hua, Ziyu

2014-01-01

Background Kernicterus still occurs around the world; however, the mechanism of bilirubin neurotoxicity remains unclear, and effective treatment strategies are lacking. To solve these problems, several kernicterus (or acute bilirubin encephalopathy) animal models have been established, but these models are difficult and expensive. Therefore, the present study was performed to establish a novel kernicterus model that is simple and affordable by injecting unconjugated bilirubin solution into the cisterna magna (CM) of ordinary newborn Sprague-Dawley (SD) rats. Methods On postnatal day 5, SD rat pups were randomly divided into bilirubin and control groups. Then, either bilirubin solution or ddH2O (pH = 8.5) was injected into the CM at 10 µg/g (bodyweight). For model characterization, neurobehavioral outcomes were observed, mortality was calculated, and bodyweight was recorded after bilirubin injection and weaning. Apoptosis in the hippocampus was detected by H&E staining, TUNEL, flow cytometry and Western blotting. When the rats were 28 days old, learning and memory ability were evaluated using the Morris water maze test. Results The bilirubin-treated rats showed apparently abnormal neurological manifestations, such as clenched fists, opisthotonos and torsion spasms. Bodyweight gain in the bilirubin-treated rats was significantly lower than that in the controls (Pbilirubin-treated rats were both dramatically higher than those of the controls (P = 0.004 and 0.017, respectively). Apoptosis and necrosis in the hippocampal nerve cells in the bilirubin-treated rats were observed. The bilirubin-treated rats performed worse than the controls on the Morris water maze test. Conclusion By injecting bilirubin into the CM, we successfully created a new kernicterus model using ordinary SD rats; the model mimics both the acute clinical manifestations and the chronic sequelae. In particular, CM injection is easy to perform; thus, more stable models for follow-up study are

Evaluation of BiliCare™ transcutaneous bilirubin device in Japanese newborns.

Science.gov (United States)

Yamana, Keiji; Morioka, Ichiro; Kurokawa, Daisuke; Fukushima, Sachiyo; Nishida, Kosuke; Ohyama, Shohei; Nishimura, Noriyuki; Nozu, Kandai; Taniguchi-Ikeda, Mariko; Nagase, Hiroaki; Fujioka, Kazumichi; Iwatani, Sota; Nakamura, Hajime; Iijima, Kazumoto

2017-10-01

Non-invasive transcutaneous bilirubin (TcB) monitoring has been widely used to screen for hyperbilirubinemia. TcB measured using the recently developed BiliCare™ system, however, has not been fully evaluated. One hundred and seven TcB measurements were obtained from 82 Japanese newborns ≥35 weeks' gestational age within 2 weeks after birth. Measurements were taken at the scaphoid fossa, conchal cavity, and lobe of the ear using BiliCare. BiliCare TcB were compared with total serum bilirubin (TB) and TcB obtained using another bilirubinometer (JM-105™). Transcutaneous bilirubin measured at all three sites significantly correlated with TB (r = 0.91, 0.93, and 0.93 at the scaphoid fossa, conchal cavity, and lobe, respectively). The mean differences were 0.1, -0.3, and 3.6 at the scaphoid fossa, conchal cavity, and lobe, respectively. BiliCare TcB at the scaphoid fossa significantly correlated with that using the JM-105 (r = 0.91). The mean difference was 0.0. BiliCare, however, produced a significantly higher and lower TcB than the JM-105 for TB bilirubin measurements taken at the scaphoid fossa or conchal cavity using BiliCare were more reliable than those at the earlobe. BiliCare TcB differed from those of the JM-105, for TB <7 or ≥15 mg/dL. © 2017 Japan Pediatric Society.

Quantitation of bilirubin conjugates with high-performance liquid chromatography in patients with low total serum bilirubin levels

NARCIS (Netherlands)

Jansen, P. L.; Cuypers, H. T.; Peters, W. H.

1984-01-01

Bilirubin mono- and diconjugates were determined by alkaline methanolysis and high-performance liquid chromatography (HPLC) in serum from patients with metastatic liver disease and liver cirrhosis. Conjugates could be detected and quantitated at normal or low total bilirubin levels. Comparison with

Serum bilirubin concentrations and incident coronary heart disease risk among patients with type 2 diabetes: the Dongfeng-Tongji cohort.

Science.gov (United States)

Wang, Jing; Wu, Xiaofen; Li, Yaru; Han, Xu; Hu, Hua; Wang, Fei; Yu, Caizheng; Li, Xiulou; Yang, Kun; Yuan, Jing; Yao, Ping; Miao, Xiaoping; Wei, Sheng; Wang, Youjie; Chen, Weihong; Liang, Yuan; Guo, Huan; Yang, Handong; Wu, Tangchun; Zhang, Xiaomin; He, Meian

2017-03-01

Elevated serum bilirubin levels are associated with decreased coronary heart disease (CHD) risk in cross-sectional studies among diabetic patients, but prospective evidence is limited. We investigated the relationship of serum bilirubin levels with incident CHD risk among type 2 diabetes patients. In a prospective study of 2918 type 2 diabetes embedded in the Dongfeng-Tongji cohort, serum total bilirubin (TBil), direct bilirubin (DBil), and indirect bilirubin (IBil) were measured at baseline. Cox proportional hazards models were used to examine the association between serum bilirubin levels and CHD risk. A total of 440 CHD cases were identified during 12,017 person-years of follow-up. Compared with extreme quartiles, the adjusted hazard ratio and 95% confidence interval of incident CHD were 0.74 (0.56-0.99) with P trend = 0.08 in IBil, while in TBil and DBil, the bilirubin-CHD associations were not significant. Moreover, serum TBil and IBil levels were interacted with drinking status on the risk of incident CHD (P interaction = 0.021 and 0.037, respectively), and the associations were evident in ever drinkers. In drinkers, when serum TBil or IBil concentrations increased 1 μmol/L, the CHD risk both decreased 6% (95% CIs 0.89-0.99 and 0.87-1.00, respectively). Serum IBil levels were marginally related to decreased incident CHD risk among type 2 diabetes. Drinking could potentially enhance the associations of serum TBil and DBil levels with incident CHD risk.

Bilirubin nomogram for prediction of significant hyperbilirubinemia in north Indian neonates.

Science.gov (United States)

Pathak, Umesh; Chawla, Deepak; Kaur, Saranjit; Jain, Suksham

2013-04-01

(i) To construct hour-specific serum total bilirubin (STB) nomogram in neonates born at =35 weeks of gestation; (ii)To evaluate efficacy of pre-discharge bilirubin measurement in predicting hyperbilirubinemia needing treatment. Diagnostic test performance in a prospective cohort study. Teaching hospital in Northern India. Healthy neonates with gestation =35 weeks or birth weight =2000 g. Serum total bilirubin was measured in all enrolled neonates at 24 ± 6, 72-96 and 96-144 h of postnatal age and when indicated clinically. Neonates were followed up during hospital stay and after discharge till completion of 7th postnatal day. Key outcome was significant hyperbilirubinemia (SHB) defined as need of phototherapy based on modified American Academy of Pediatrics (AAP) guidelines. In neonates born at 38 or more weeks of gestation middle line and in neonates born at 37 or less completed weeks of gestation, lower line of phototherapy thresholds were used to initiate phototherapy. For construction of nomogram, STB values were clubbed in six-hour epochs (age ± 3 hours) for postnatal age up to 48 h and twelve-hour epochs (age ± 6 hours) for age beyond 48 h. Predictive ability of the nomogram was assessed by calculating sensitivity, specificity, positive predictive value, negative predictive value and likelihood ratio, by plotting receiver-operating characteristics (ROC) curve and calculating c-statistic. 997 neonates (birth weight: 2627 ± 536 g, gestation: 37.8 ± 1.5 weeks) were enrolled, of which 931 completed followup. Among enrolled neonates 344 (34.5%) were low birth weight. Rate of exclusive breastfeeding during hospital stay was more than 80%. Bilirubin nomogram was constructed using 40th, 75th and 95th percentile values of hour-specific bilirubin. Pre-discharge STB of =95th percentile was assigned to be in high-risk zone, between 75th and 94th centile in upper-intermediate risk zone, between 40th and 74th centile in lower-intermediate risk zone and below 40th

Cell damage by bilirubin and light

International Nuclear Information System (INIS)

Granli, T.

1993-01-01

Large doses of light are given to newborns during phototherapy for hyperbilirubinemia. Tissues containing concentrations of bilirubin almost in the mM range may be subjected to irradiation. Therefore it is of interest to study cellular effects of light and bilirubin on cells. In order to select the optimal wavelength, possible detrimental effects of light on cells must be taken into consideration among a number of other factors. In this study cellular effects of selected wavelengths of blue-green light are compared. It is not clear whether cullular damage occurs in vivo during phototherapy of newborns. Since a possibility exists that some adverse effects are caused by light, one should choose wavelengths where these effects are minimal without loosing therapeutic efficiency. Todays knowledge of the photochemical mechanisms of phototherapy, indicates that short waved light with wavelengths below 450 nm has a low therapeutic effect. The data in this paper indicate that the cellular damage is most severe at short wavelengths, and these should be reduced to a minimum in the spectra of phototherapy lamps. Further studies of possible side effects of phototherapy should be made. 64 refs., 34 figs., 1 tab

beta-Glucuronidase-resistant bilirubin glucuronide isomers in cholestatic liver disease--determination of bilirubin metabolites in serum by means of high-pressure liquid chromatography

NARCIS (Netherlands)

Jansen, P. L.

1981-01-01

"Direct reacting bilirubin" in serum of patients with cholestatic liver disease and in serum of bile duct-ligated rats consists of a complex mixture of bilirubin metabolites. These metabolites were studied by means of high-pressure liquid chromatography. Bilirubin glucuronides in normal bile are

Anti-Genotoxic Potential of Bilirubin In Vivo

DEFF Research Database (Denmark)

Wallner, Marlies; Antl, Nadja; Rittmannsberger, Barbara

2013-01-01

The bile pigment bilirubin is a known antioxidant and is associated with protection from cancer and cardiovascular disease (CVD) when present in too strong concentrations. Unconjugated bilirubin (UCB) might also possess anti-genotoxic potential by preventing oxidative damage to DNA. Moderately...... elevated bilirubin levels are found in individuals with Gilbert syndrome and more severe in the hyperbilirubinemic Gunn rat model. This study was therefore aimed to assess the levels of oxidative damage to DNA in Gilbert syndrome subjects and Gunn rats compared to matched controls. Seventy-six individuals...

Higher Bilirubin Levels of Healthy Living Liver Donors Are Associated With Lower Posttransplant Hepatocellular Carcinoma Recurrence.

Science.gov (United States)

Han, Sangbin; Yang, Ju Dong; Sinn, Dong Hyun; Ko, Justin Sangwook; Kim, Jong Man; Shin, Jun Chul; Son, Hee Jeong; Gwak, Mi Sook; Joh, Jae-Won; Kim, Gaab Soo

2016-09-01

Serum bilirubin level, which may reflect the host defense against increased oxidative stress, is inversely associated with the risk of cancer development. In liver transplantation, the intrinsic bilirubin metabolism of donor liver is subsequently translated into recipient. Thus, we hypothesized that liver transplantation conducted with living donors with higher serum bilirubin reduces hepatocellular carcinoma (HCC) recurrence. Two hundred fifty recipients who underwent liver transplantation for treating HCC within the Milan criteria were included in the study. The association between donor preoperative total bilirubin concentration and the risk of HCC recurrence was analyzed using the Fine and Gray regression model with posttransplant death as a competing risk event with adjustment for tumor biology including α-fetoprotein, histological differentiation, and microvascular invasion. All donors were confirmed to have no underlying hepatobiliary diseases or hematological disorders. Donor preoperative total bilirubin concentration was 0.7 mg/dL in median and ranged from 0.2 to 2.7 mg/dL. Thirty-five (14.0%) recipients developed HCC recurrence. Multivariable analysis demonstrated that donor preoperative total bilirubin concentration was inversely associated with the recurrence risk (hazard ratio, 0.22; 95% confidence interval, 0.07-0.72; P = 0.013). The highest (≥1.0 mg/dL) versus lowest (≤0.6 mg/dL) tertile of donor preoperative total bilirubin showed a significant reduction of the recurrence risk (hazard ratio, 0.28; 95% confidence interval, 0.11-0.70; P = 0.006). Hepatocellular carcinoma recurrence risk decreases in relation to the increase in total serum bilirubin level of healthy living donors without underlying hepatobiliary or hematological disorders. Further validation of bilirubin as a potent anticancer substance against HCC is warranted.

A Prospective Comparison of Transcutaneous and Serum Bilirubin Within Brief Time Intervals.

Science.gov (United States)

Jones, Denise F; McRea, Abigail R; Knowles, James D; Lin, Feng-Chang; Burnette, Erin; Reller, Lara A; Lohr, Jacob A

2017-10-01

The American Academy of Pediatrics recommends screening newborns ≥35 weeks' gestation with total serum bilirubin (TSB) or transcutaneous bilirubin (TcB) to detect hyperbilirubinemia. Retrospective studies show TcB measurements strongly correlate with TSB; however, few prospective trials document this relationship. Furthermore, Dräger's newest TcB instrument, JM-105, remains unstudied in the United States. We measure TcB on foreheads and sternums of newborns using JM-105 and Bilichek devices within 30 minutes of TSB measurement. We find best overall TcB/TSB correlation with JM-105 on the sternum (mean TcB-TSB difference: -0.21 ± 1.15 mg/dL). Correlations between paired measurements for TcB on the sternum using JM-105 were 0.93 for all TSB levels (n = 178), 0.82 for TSB > 10 (n = 19), 0.69 for TSB > 12 (n = 11), and 0.52 for TSB > 15 (n = 6). TcB accuracy via JM-105 on the sternum significantly differed among races ( P < .001). For 5% of paired measurements, TcB with JM-105 on the sternum underestimated TSB by ≥2 mg/dL, and for <1% by ≥3 mg/dL.

Sistem Pencegahan UDP DNS Flood Dengan Filter Firewall Pada Router Mikrotik

Directory of Open Access Journals (Sweden)

Doni Aprilianto

2017-05-01

Full Text Available Serangan terhadap server jaringan dapat terjadi kapan saja,  jenis serangan yang dapat menyebabkan efek yang signifikan pada sebuah router adalah UDP-Flooding. UDP (User Datagram Protocol-Flooding adalah jenis serangan yang memanfaatkan protokol UDP dengan mengurangi sambungan (connectionless untuk menyerang target. Dalam analisis ini menggunakan metode penelitian deskriptif untuk memperoleh data secara langsung dengan melakukan teknik flooding serta teknik pencegahannya terhadap server yang telah dirancang. Dengan menggunakan Filter Rules yang telah dibuat, packet yang melalui port DNS selain IP Address yang telah di allow jika mencoba melakukan request atau flood DNS ke IP Public ISP pada router mikrotik, maka packet tersebut akan langsung di drop oleh pengaturan rules tersebut. kesimpulan yang dapat diambil yaitu penerapan filter firewall pada router mikrotik dapat mengurangi jumlah paket data UDP yang dikirimkan oleh attacker melalui port DNS sebanyak 60% dari jumlah paket yang masuk jika tanpa firewall.

Identification and characterization of human UDP-glucuronosyltransferases responsible for the in-vitro glucuronidation of arctigenin.

Science.gov (United States)

Xin, Hong; Xia, Yang-Liu; Hou, Jie; Wang, Ping; He, Wei; Yang, Ling; Ge, Guang-Bo; Xu, Wei

2015-12-01

This study aimed to characterize the glucuronidation pathway of arctigenin (AR) in human liver microsomes (HLM) and human intestine microsomes (HIM). HLM and HIM incubation systems were employed to catalyse the formation of AR glucuronide. The glucuronidation activity of commercially recombinant UGT isoforms towards AR was screened. A combination of chemical inhibition assay and kinetic analysis was used to determine the UGT isoforms involved in the glucuronidation of AR in HLM and HIM. AR could be extensively metabolized to one mono-glucuronide in HLM and HIM. The mono-glucuronide was biosynthesized and characterized as 4'-O-glucuronide. UGT1A1, 1A3, 1A7, 1A8, 1A9, 1A10, 2B4, 2B7 and 2B17 participated in the formation of 4'-O-G, while UGT2B17 demonstrated the highest catalytic activity in this biotransformation. Both kinetic analysis and chemical inhibition assays demonstrated that UGT1A9, UGT2B7 and UGT2B17 played important roles in AR-4'-O-glucuronidation in HLM. Furthermore, HIM demonstrated moderate efficiency for AR-4'-O-glucuronidation, implying that AR may undergo a first-pass metabolism during the absorption process. UGT1A9, UGT2B7 and UGT2B17 were the major isoforms responsible for the 4'-O-glucuronidation of AR in HLM, while UGT2B7 and UGT2B17 were the major contributors to this biotransformation in HIM. © 2015 Royal Pharmaceutical Society.

Development of bilirubin metabolism and transport in the neonate.

Science.gov (United States)

Gartner, L M

1977-01-01

Comprehensive physiologic study of the developmental processes of bilirubin metabolism and transport reveal a complex interaction of various steps. Phase I Physiologic Jaundice results from the simultaneous increase in bilirubin load presented to the liver and decrease in bilirubin conjugating capacity. Phase II appears to result from a mild decrease in hepatic uptake capacity, coupled with the continuing increase in bilirubin load. Since these results are based upon studies of newborn rhesus monkeys, confirmatory studies in human neonates are required. Perhaps the most challenging aspect of these observations relates to the concept of a developmentally determined delicate imbalance between two functions. It is unlikely that pharmacologic agents could radically alter a single function. Therefore, it is perhaps more realistic to think that drug treatments which only slightly alter two functions simultaneously but in the appropriate directions could more effectively reduce the risk of toxicity. Thus, a mild increase in bilirubin conjugation coupled with a small but significant decrease in bilirubin load could markedly alleviate the severity of physiologic jaundice.