Science.gov

Sample records for bilirubin oxidase bound

  1. Characterization of copper atoms in bilirubin oxidase by spectroscopic analyses.

    PubMed

    Gotoh, Y; Kondo, Y; Kaji, H; Takeda, A; Samejima, T

    1989-10-01

    Bilirubin oxidase [EC 1.3.3.5], purified from the culture medium of Myrothecium verrucaria, was found to contain two blue copper atoms per protein molecule with a molecular weight of ca. 52 kDa. The two copper atoms were estimated to be in the all cupric state by the cuproine colorimetric method and also atomic absorption analysis. We could remove the reduce cuprous ions from the holo enzyme by adding ascorbate, followed by a KCN solution, yielding an apo-enzyme with no activity. The apo-enzyme can be reconstituted with Cu or other divalent cations such as Co, Fe, and Cd, with accompanying recovery of the enzyme activity. The activity recovery depended upon the species of cation employed; Cu being most effective, an almost 100% recovery, and Cd the least, only a 25% recovery. We could obtain information on the copper ions and their coordination structure by spectroscopic analyses of the apo- and reconstituted enzymes, obtaining such as absorption, CD, MCD, and XPS spectra. The bilirubin oxidase catalyzed-reaction was a second order reaction with respect to copper bound with protein. The donor set was of the CuSS*N2 (S = Cys, S* = Met, N = His) type, i.e., the same as in the case of blue copper proteins. On studying the Co-substituted enzyme, it was revealed that the copper site of the enzyme had a 4-coordinated structure.

  2. Enzymatic assay for conjugated bilirubin (Bc) in serum using bilirubin oxidase (BOD).

    PubMed

    Kimura, S; Iyama, S; Yamaguchi, Y; Hayashi, S; Yanagihara, T

    1999-01-01

    We described an automated enzymatic assay for conjugated bilirubin (Bc) in serum using the Iatro D-Bil kit, with bilirubin oxidase (EC 1.3.3.5 BOD) from Myrothecium species. The specificity of the enzyme in the Iatro D-Bil kit was examined by analyzing unconjugated bilirubin (Bu), delta bilirubin (Bdelta), and Bc with high-performance liquid chromatography (HPLC), before and after the enzymatic reaction using BOD. The within-assay coefficients of variation (CV) of this method were 0.58 to 5.00% (n = 20) at 1.4 to 155.8 micromol/L. Day-to-day Cvs ranged from 1.61 to 7.14% at 1.2 to 182.1 micromol/L. The analytical recovery was 96 to 101%. The presence of ascorbic acid, reduced glutathione, L-cysteine, uric acid, urea, creatinine, glucose, lipemic material, anticoagulants, hemoglobin, or human serum albumin did not affect this assay system. The correlation coefficient between values obtained with the Iatro D-Bil kit (y) and HPLC method as reference for conjugated fractions (x) was; r = 0.983, y = 0.952x + 8.851 micromol/L, Sy/x = 11.97 (n = 56). We studied serum Bc levels, not including Bu and Bdelta, in patients with hepatic diseases or autoimmune hemolytic anemia. Levels of Bc obtained by the proposed method changed more rapidly than did those of direct bilirubin (D-Bil) obtained by diazo-dye method during the course of the diseases. Copyright 1999 Wiley-Liss, Inc.

  3. Purification, characterization and decolorization of bilirubin oxidase from Myrothecium verrucaria 3.2190

    USDA-ARS?s Scientific Manuscript database

    Myrothecium verrucaria 3.2190 is a nonligninolytic fungus that produces bilirubin oxidase. Both Myrothecium verrucaria and the extracellular bilirubin oxidase were tested for their ability to decolorize indigo carmine. The biosorption and biodegradation of the dye were detected during the process of...

  4. Inducible bilirubin oxidase: A novel function for the mouse cytochrome P450 2A5

    SciTech Connect

    Abu-Bakar, A'edah; Arthur, Dionne Maioha; Aganovic, Simona; Ng, Jack C.; Lang, Matti A.

    2011-11-15

    We have previously shown that bilirubin (BR), a breakdown product of haem, is a strong inhibitor and a high affinity substrate of the mouse cytochrome P450 2A5 (CYP2A5). The antioxidant BR, which is cytotoxic at high concentrations, is potentially useful in cellular protection against oxygen radicals if its intracellular levels can be strictly controlled. The mechanisms that regulate cellular BR levels are still obscure. In this paper we provide preliminary evidence for a novel function of CYP2A5 as hepatic 'BR oxidase'. A high-performance liquid chromatography/electrospray ionisation mass spectrometry screening showed that recombinant yeast microsomes expressing the CYP2A5 oxidise BR to biliverdin, as the main metabolite, and to three other smaller products with m/z values of 301, 315 and 333. The metabolic profile is significantly different from that of chemical oxidation of BR. In chemical oxidation the smaller products were the main metabolites. This suggests that the enzymatic reaction is selective, towards biliverdin production. Bilirubin treatment of primary hepatocytes increased the CYP2A5 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 CYP2A5 compared to cells treated only with CHX. Collectively, the observations suggest that the CYP2A5 is potentially an inducible 'BR oxidase' where BR may accelerate its own metabolism through stabilization of the CYP2A5 protein. It is possible that this metabolic pathway is potentially part of the machinery controlling intracellular BR levels in transient oxidative stress situations, in which high amounts of BR are produced. -- Highlights: Black-Right-Pointing-Pointer CYP2A5 metabolizes bilirubin to biliverdin and dipyrroles. Black-Right-Pointing-Pointer Bilirubin increased the hepatic CYP2A5 protein and activity levels. Black-Right-Pointing-Pointer Bilirubin does not change the hepatic CYP2A5

  5. Bilirubin oxidase from Magnaporthe oryzae: an attractive new enzyme for biotechnological applications

    PubMed Central

    Durand, Fabien; Gounel, Sébastien; Kjaergaard, Christian H.; Solomon, Edward I.

    2013-01-01

    A novel bilirubin oxidase (BOD), from the rice blast fungus Magnaporthe oryzae, has been identified and isolated. The 64-kDa protein containing four coppers was successfully overexpressed in Pichia pastoris and purified to homogeneity in one step. Protein yield is more than 100 mg for 2 L culture, twice that of Myrothecium verrucaria. The kcat/Km ratio for conjugated bilirubin (1,513 mM −1 s−1) is higher than that obtained for the BOD from M. verrucaria expressed in native fungus (980 mM−1 s−1), with the lowest Km measured for any BOD highly desirable for detection of bilirubin in medical samples. In addition, this protein exhibits a half-life for deactivation >300 min at 37 °C, high stability at pH 7, and high tolerance towards urea, making it an ideal candidate for the elaboration of biofuel cells, powering implantable medical devices. Finally, this new BOD is efficient in decolorizing textile dyes such as Remazol brilliant Blue R, making it useful for environmentally friendly industrial applications. PMID:22350257

  6. Bilirubin oxidase from Magnaporthe oryzae: an attractive new enzyme for biotechnological applications.

    PubMed

    Durand, Fabien; Gounel, Sébastien; Kjaergaard, Christian H; Solomon, Edward I; Mano, Nicolas

    2012-12-01

    A novel bilirubin oxidase (BOD), from the rice blast fungus Magnaporthe oryzae, has been identified and isolated. The 64-kDa protein containing four coppers was successfully overexpressed in Pichia pastoris and purified to homogeneity in one step. Protein yield is more than 100 mg for 2 L culture, twice that of Myrothecium verrucaria. The k(cat)/K(m) ratio for conjugated bilirubin (1,513 mM⁻¹ s⁻¹) is higher than that obtained for the BOD from M. verrucaria expressed in native fungus (980 mM⁻¹ s⁻¹), with the lowest K(m) measured for any BOD highly desirable for detection of bilirubin in medical samples. In addition, this protein exhibits a half-life for deactivation >300 min at 37 °C, high stability at pH 7, and high tolerance towards urea, making it an ideal candidate for the elaboration of biofuel cells, powering implantable medical devices. Finally, this new BOD is efficient in decolorizing textile dyes such as Remazol brilliant Blue R, making it useful for environmentally friendly industrial applications.

  7. Circular dichroism study of the interaction between mutagens and bilirubin bound to different binding sites of serum albumins.

    PubMed

    Orlov, Sergey; Goncharova, Iryna; Urbanová, Marie

    2014-05-21

    Although recent investigations have shown that bilirubin not only has a negative role in the organism but also exhibits significant antimutagenic properties, the mechanisms of interactions between bilirubin and mutagens are not clear. In this study, interaction between bilirubin bound to different binding sites of mammalian serum albumins with structural analogues of the mutagens 2-aminofluorene, 2,7-diaminofluorene and mutagen 2,4,7-trinitrofluorenone were investigated by circular dichroism and absorption spectroscopy. Homological human and bovine serum albumins were used as chiral matrices, which preferentially bind different conformers of bilirubin in the primary binding sites and make it observable by circular dichroism. These molecular systems approximated a real system for the study of mutagens in blood serum. Differences between the interaction of bilirubin bound to primary and to secondary binding sites of serum albumins with mutagens were shown. For bilirubin bound to secondary binding sites with low affinity, partial displacement and the formation of self-associates were observed in all studied mutagens. The associates of bilirubin bound to primary binding sites of serum albumins are formed with 2-aminofluorene and 2,4,7-trinitrofluorenone. It was proposed that 2,7-diaminofluorene does not interact with bilirubin bound to primary sites of human and bovine serum albumins due to the spatial hindrance of the albumins binding domains. The spatial arrangement of the bilirubin bound to serum albumin along with the studied mutagens was modelled using ligand docking, which revealed a possibility of an arrangement of the both bilirubin and 2-aminofluorene and 2,4,7-trinitrofluorenone in the primary binding site of human serum albumin. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Circular dichroism study of the interaction between mutagens and bilirubin bound to different binding sites of serum albumins

    NASA Astrophysics Data System (ADS)

    Orlov, Sergey; Goncharova, Iryna; Urbanová, Marie

    Although recent investigations have shown that bilirubin not only has a negative role in the organism but also exhibits significant antimutagenic properties, the mechanisms of interactions between bilirubin and mutagens are not clear. In this study, interaction between bilirubin bound to different binding sites of mammalian serum albumins with structural analogues of the mutagens 2-aminofluorene, 2,7-diaminofluorene and mutagen 2,4,7-trinitrofluorenone were investigated by circular dichroism and absorption spectroscopy. Homological human and bovine serum albumins were used as chiral matrices, which preferentially bind different conformers of bilirubin in the primary binding sites and make it observable by circular dichroism. These molecular systems approximated a real system for the study of mutagens in blood serum. Differences between the interaction of bilirubin bound to primary and to secondary binding sites of serum albumins with mutagens were shown. For bilirubin bound to secondary binding sites with low affinity, partial displacement and the formation of self-associates were observed in all studied mutagens. The associates of bilirubin bound to primary binding sites of serum albumins are formed with 2-aminofluorene and 2,4,7-trinitrofluorenone. It was proposed that 2,7-diaminofluorene does not interact with bilirubin bound to primary sites of human and bovine serum albumins due to the spatial hindrance of the albumins binding domains. The spatial arrangement of the bilirubin bound to serum albumin along with the studied mutagens was modelled using ligand docking, which revealed a possibility of an arrangement of the both bilirubin and 2-aminofluorene and 2,4,7-trinitrofluorenone in the primary binding site of human serum albumin.

  9. Bilirubin Oxidase from Bacillus pumilus: A promising enzyme for the elaboration of efficient cathodes in Biofuel cells

    PubMed Central

    Durand, Fabien; Kjaergaard, Christian Hauge; Suraniti, Emmanuel; Gounel, Sébastien; Hadt, Ryan G.; Solomon, Edward I; Mano, Nicolas

    2013-01-01

    A CotA Multicopper Oxidase (MCO) from Bacillus pumilus, previously identified as a laccase, has been studied and characterized as a new bacterial Bilirubin Oxidase (BOD). The 59kDa protein containing four coppers, was successfully over-expressed in Escherichia coli and purified to homogeneity in one step. This 509 amino-acid enzyme, having 67% and 26% sequence identity with CotA from Bacillus subtilis and BOD from Myrothecium verrucaria, respectively, shows higher turnover activity towards bilirubin compared to other bacterial MCOs. The current density for O2 reduction, when immobilized in a redox hydrogel, is only 12% smaller than the current obtained with Trachyderma tsunodae BOD. Under continuous electrocatalysis, an electrode modified with the new BOD is more stable, and has a higher tolerance towards NaCl, than a T. tsunodae BOD modified electrode. This makes BOD from B. pumilus an attractive new candidate for application in biofuel cells and biosensors. PMID:22410485

  10. Decolorization and biodegradation of remazol brilliant blue R by bilirubin oxidase.

    PubMed

    Liu, Youxun; Huang, Juan; Zhang, Xiaoyu

    2009-12-01

    The dye-decolorizing potential of bilirubin oxidase (BOX) was demonstrated for an anthraquinone dye, remazol brilliant blue R (RBBR). The dye was decolorized 40% within 4 h by the BOX alone, whereas it was more efficient in the presence of 2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), showing 91.5% decolorization within 25 min. The effects of operational parameters on decolorization were examined. The results showed that the decolorization efficiency decreased with increasing RBBR concentration, and a marked inhibition effect was exhibited when the dye concentrations were above 100 mg l(-1). The optimum temperature for enzymatic decolorization was 40 degrees C. BOX showed efficient decolorization of the dye with a wide pH range of 5-8.5. The maximum decolorization activity occurred at pH 8 with ABTS and at pH 5 without ABTS. Analysis of RBBR ultraviolet and visible (UV-VIS) spectra after BOX treatment indicated that the decolorization of RBBR was due to biodegradation. Our results suggested that ABTS can serve as an electron mediator to facilitate the oxidation of RBBR, and the BOX-ABTS mediator-involved dye decolorization mechanism was similar to that of laccase. Operation over a wide range of pH and efficient decolorization suggested that the BOX can be used to decolorize synthetic dyes from effluents, especially for anthraquinonic dyes.

  11. A spectroscopic study of the wavelength-dependent photoisomerizations of bilirubins bound to human serum albumin

    NASA Astrophysics Data System (ADS)

    Mazzoni, Marina; Agati, Giovanni; Pratesi, Riccardo; Persico, Maurizio

    2005-12-01

    The wavelength-dependent photoisomerizations of the asymmetric bilirubin BR-IXα and of the symmetric bilirubin-IIIα (BR-III) and mesobilirubin-XIIIα (MBR-XIII) bound to human serum albumin (HSA) in aqueous solution were analysed with the help of an exciton coupling model. The modelling was based on the absorption and circular dichroism (CD) spectra (bisignate Cotton effect). Time-dependent density functional theory (TD-DFT) of the free BR-IX molecule suggested the presence of two main bands of exciton coupling character in the blue region of the spectrum, and other weaker bands of charge transfer character at longer wavelengths. These peculiarities were taken into account to fit the photoisomerization quantum yields in the blue-green region as functions of the wavelength, obtaining the bandshape of the exciton coupling bands from the experimental CD spectra. The other excitons were extracted from the decomposition of the band resulting from the difference between the absorption spectrum and the sum (normalized-to-absorption) of the two CD excitons. We expressed photoisomerization quantum yields in terms of the sum of the contributions to photon absorption deriving from all the exciton states normalized to total absorption. For all the reversible photoprocesses of bilirubins and for the irreversible one of BR-IXα in HSA (i.e. lumirubin formation), we give reliable mean values of the individual state excitation probabilities and photoisomerization efficiencies in the pigment protein complex.

  12. Bilirubin Oxidase from Myrothecium verrucaria Physically Absorbed on Graphite Electrodes. Insights into the Alternative Resting Form and the Sources of Activity Loss.

    PubMed

    Tasca, Federico; Farias, Diego; Castro, Carmen; Acuna-Rougier, Cristina; Antiochia, Riccarda

    2015-01-01

    The oxygen reduction reaction is one of the most important chemical processes in energy converting systems and living organisms. Mediator-less, direct electro-catalytic reduction of oxygen to water was achieved on spectrographite electrodes modified by physical adsorption of bilirubin oxidases from Myrothecium verrucaria. The existence of an alternative resting form of the enzyme is validated. The effect on the catalytic cycle of temperature, pH and the presence of halogens in the buffer was investigated. Previous results on the electrochemistry of bilirubin oxidase and on the impact of the presence of halogens are reviewed and reinterpreted.

  13. Bilirubin Oxidase from Myrothecium verrucaria Physically Absorbed on Graphite Electrodes. Insights into the Alternative Resting Form and the Sources of Activity Loss

    PubMed Central

    Tasca, Federico; Farias, Diego; Castro, Carmen; Acuna-Rougier, Cristina; Antiochia, Riccarda

    2015-01-01

    The oxygen reduction reaction is one of the most important chemical processes in energy converting systems and living organisms. Mediator-less, direct electro-catalytic reduction of oxygen to water was achieved on spectrographite electrodes modified by physical adsorption of bilirubin oxidases from Myrothecium verrucaria. The existence of an alternative resting form of the enzyme is validated. The effect on the catalytic cycle of temperature, pH and the presence of halogens in the buffer was investigated. Previous results on the electrochemistry of bilirubin oxidase and on the impact of the presence of halogens are reviewed and reinterpreted. PMID:26196288

  14. Bromophenol blue binding to mammalian albumins and displacement of albumin-bound bilirubin.

    PubMed

    Kim, B Boon; Abdul Kadir, H; Tayyab, S

    2008-10-15

    Interaction of bromophenol blue (BPB) with serum albumins from different mammalian species, namely, human (HSA), bovine (BSA), goat (GSA), sheep (SSA), rabbit (RbSA), porcine (PSA) and dog (DSA) was studied using absorption and absorption difference spectroscopy. BPB-albumin complexes showed significant differences in the spectral characteristics, i.e., extent of bathochromic shift and hypochromism relative to the spectral features of free BPB. Absorption difference spectra of these complexes also showed variations in the position of maxima and absorption difference (deltaAbs.) values. Absorption difference spectra of different bilirubin (BR)-albumin complexes showed a significant blue shift accompanied by decrease in deltaAbs. values in presence of BPB which were indicative of the displacement of bound BR from its binding site in BR-albumin complexes. These changes in the difference spectral characteristics of BR-albumin complexes were more marked at higher BPB concentration. However, the extent of these changes was different for different BR-albumin complexes. Taken together, all these results suggest that BPB partially shares BR binding site on albumin and different mammalian albumins show differences in the microenvironment of the BR/BPB binding site.

  15. Study on dioxygen reduction by mutational modifications of the hydrogen bond network leading from bulk water to the trinuclear copper center in bilirubin oxidase

    SciTech Connect

    Morishita, Hirotoshi; Kurita, Daisuke; Kataoka, Kunishige; Sakurai, Takeshi

    2014-07-18

    Highlights: • Proton transport pathway in bilirubin oxidase was mutated. • Two intermediates in the dioxygen reduction steps were trapped and characterized. • A specific glutamate for dioxygen reduction by multicopper oxidases was identified. - Abstract: The hydrogen bond network leading from bulk water to the trinuclear copper center in bilirubin oxidase is constructed with Glu463 and water molecules to transport protons for the four-electron reduction of dioxygen. Substitutions of Glu463 with Gln or Ala were attributed to virtually complete loss or significant reduction in enzymatic activities due to an inhibition of the proton transfer steps to dioxygen. The single turnover reaction of the Glu463Gln mutant afforded the highly magnetically interacted intermediate II (native intermediate) with a broad g = 1.96 electron paramagnetic resonance signal detectable at cryogenic temperatures. Reactions of the double mutants, Cys457Ser/Glu463Gln and Cys457Ser/Glu463Ala afforded the intermediate I (peroxide intermediate) because the type I copper center to donate the fourth electron to dioxygen was vacant in addition to the interference of proton transport due to the mutation at Glu463. The intermediate I gave no electron paramagnetic resonance signal, but the type II copper signal became detectable with the decay of the intermediate I. Structural and functional similarities between multicopper oxidases are discussed based on the present mutation at Glu463 in bilirubin oxidase.

  16. X-ray analysis of bilirubin oxidase from Myrothecium verrucaria at 2.3 Å resolution using a twinned crystal

    PubMed Central

    Mizutani, Kimihiko; Toyoda, Mayuko; Sagara, Kenta; Takahashi, Nobuyuki; Sato, Atsuko; Kamitaka, Yuji; Tsujimura, Seiya; Nakanishi, Yuji; Sugiura, Toshiyuki; Yamaguchi, Shotaro; Kano, Kenji; Mikami, Bunzo

    2010-01-01

    Bilirubin oxidase (BOD), a multicopper oxidase found in Myrothecium verrucaria, catalyzes the oxidation of bilirubin to biliverdin. Oxygen is the electron acceptor and is reduced to water. BOD is used for diagnostic analysis of bilirubin in serum and has attracted considerable attention as an enzymatic catalyst for the cathode of biofuel cells that work under neutral conditions. Here, the crystal structure of BOD is reported for the first time. Blue bipyramid-shaped crystals of BOD obtained in 2-methyl-2,4-pentanediol (MPD) and ammonium sulfate solution were merohedrally twinned in space group P63. Structure determination was achieved by the single anomalous diffraction (SAD) method using the anomalous diffraction of Cu atoms and synchrotron radiation and twin refinement was performed in the resolution range 33–2.3 Å. The overall organization of BOD is almost the same as that of other multicopper oxidases: the protein is folded into three domains and a total of four copper-binding sites are found in domains 1 and 3. Although the four copper-binding sites were almost identical to those of other multicopper oxidases, the hydrophilic Asn residue (at the same position as a hydrophobic residue such as Leu in other multicopper oxidases) very close to the type I copper might contribute to the characteristically high redox potential of BOD. PMID:20606269

  17. Increasing the catalytic activity of Bilirubin oxidase from Bacillus pumilus: Importance of host strain and chaperones proteins.

    PubMed

    Gounel, Sébastien; Rouhana, Jad; Stines-Chaumeil, Claire; Cadet, Marine; Mano, Nicolas

    2016-07-20

    Aggregation of recombinant proteins into inclusion bodies (IBs) is the main problem of the expression of multicopper oxidase in Escherichia coli. It is usually attributed to inefficient folding of proteins due to the lack of copper and/or unavailability of chaperone proteins. The general strategies reported to overcome this issue have been focused on increasing the intracellular copper concentration. Here we report a complementary method to optimize the expression in E. coli of a promising Bilirubin oxidase (BOD) isolated from Bacillus pumilus. First, as this BOD has a disulfide bridge, we switched E.coli strain from BL21 (DE3) to Origami B (DE3), known to promote the formation of disulfide bridges in the bacterial cytoplasm. In a second step, we investigate the effect of co-expression of chaperone proteins on the protein production and specific activity. Our strategy allowed increasing the final amount of enzyme by 858% and its catalytic rate constant by 83%. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Bilirubin Test

    MedlinePlus

    ... Also known as: Total Bilirubin; TBIL; Neonatal Bilirubin; Direct Bilirubin; Conjugated Bilirubin; Indirect Bilirubin; Unconjugated Bilirubin Formal ... Hepatitis B ; Hepatitis C ; Complete Blood Count ; Urinalysis ; Direct Antiglobulin Test ; Haptoglobin ; Reticulocyte Count All content on ...

  19. Heat and drying time modulate the O2 reduction current of modified glassy carbon electrodes with bilirubin oxidases.

    PubMed

    Suraniti, Emmanuel; Abintou, Margot; Durand, Fabien; Mano, Nicolas

    2012-12-01

    Here we show that the magnitude of the O(2) reduction current of cathodes based on Bilirubin oxidases (BOD) immobilized into a redox hydrogel strongly depends on the drying conditions such as the curing time and temperature of drying as well as the thermostability of the BOD. To illustrate this effect, we performed experiments with two different BODs: one labile BOD from Trachyderma tsunodae and one highly thermostable BOD from Bacillus pumilus with different preparation protocols. The balance between the kinetics of formation of the hydrogel and the enzyme stability leads to optimal drying conditions of 2h at 25°C for both types of BODs when the most widespread protocol uses 18 hours at ambient temperature. For drying times longer than two hours, the catalytic current decreases because of the instability of T. tsunodae. Finally the optimal conditions for BOD from T. tsunodae lead to a faster preparation of electrodes than with the protocol currently in use (2h vs. 18h) and catalytic currents for oxygen reduction 100% higher (1040μA/cm(2) vs. 517μA/cm(2)).

  20. Application of poly[oxyethylene(dimethylimino)propyl-(dimethylimino)ethylene] as enzyme stabilizer for bilirubin oxidase immobilized electrode.

    PubMed

    Katano, Hajime; Uematsu, Kohei; Hibi, Takao; Ikeda, Tokuji; Tsukatani, Toshihide

    2009-09-01

    It has been shown that polyammonium cations comprising quaternary ammonium and hydrophilic groups such as amide and hydroxyl groups stabilize a redox enzyme bilirubin oxidase (BOD). The BOD catalyzes the reaction: 4[Fe(CN)6]4- + 4H+ + O2 --> 4[Fe(CN)6]3- + 2H2O, and has been a promising enzyme for use as a cathode catalyst in biofuel cells. In this study, the stabilizing effect of poly[oxyethylene(dimethylimino)propyl(dimethylimino)ethylene] (PA1) on BOD has been investigated. The sample solution containing BOD and the PA1 salt was kept at a given temperature, and the loss of the enzymatic activity was detected after given stored times. The activity decreased exponentially with stored time so that the first-order rate-constant of inactivation was determined. The inactivation rate-constant lowered with increasing the concentration of the PA1 salt, suggesting that BOD was stabilized by the association with the PA1 cation. The PA1 cation may act like a protective colloid or decrease the local disorder of BOD by its wrapping. A membrane-covered electrode containing BOD, PA1, and [Fe(CN)6](4-/3-) in the internal solution phase was examined in air-saturated aqueous solution. The electrode gave a well-defined current-potential curve with a steady state limiting current due to the PA1-[Fe(CN)6](4-/3-) polyion complex-mediated bioelectrocatalytic current for the reduction of O2. The decreasing of the steady state limiting current became slower in the presence of the PA1 salt, indicating again the stabilizing effect of PA1 cation on BOD.

  1. The pH dependence of the cathodic peak potential of the active sites in bilirubin oxidase.

    PubMed

    Filip, Jaroslav; Tkac, Jan

    2014-04-01

    This is the first study showing pH dependence of three distinct redox sites within bilirubin oxidase (BOD) adsorbed on a nanocomposite modified electrode. The 1st redox centre with the highest redox potential Ec(1st)=404 mV vs. Ag/AgCl (614 mV vs. NHE at pH7.0) exhibited pH dependence with a slope -dEc(1st)/dpH=66(±3) mV under a non-turnover process. The 2nd redox centre with a potential Ec(2nd)=228 mV vs. Ag/AgCl (438 mV vs. NHE at pH7.0) was not dependent on pH in the absence and presence of O2. Finally, the 3rd redox site with a redox potential Ec(3rd)=92 mV vs. Ag/AgCl (302 mV vs. NHE at pH7.0) exhibited pH dependence for a cathodic process with -dEc(3rd)/dpH=70(±6) mV and for anodic process with -dEa(3rd)/dpH=73(±2) mV, respectively. Moreover, two break points for dependence of Ec(1st) or Ec(3rd) on pH were observed for the 1st (T1) site and the 3rd site assigned to involvement of two acidic amino acids (Asp105 and Glu463). A diagram of a potential difference between cathodic peaks of BOD as a dependence on pH is shown. The results obtained can be of interest for construction of biofuel cells based on BOD such as for generation of a low level of electricity from body fluids.

  2. Bilirubin oxidase from Myrothecium verrucaria: X-ray determination of the complete crystal structure and a rational surface modification for enhanced electrocatalytic O2 reduction.

    PubMed

    Cracknell, James A; McNamara, Thomas P; Lowe, Edward D; Blanford, Christopher F

    2011-07-07

    The blue multi-copper oxidase bilirubin oxidase (BOx) from the ascomycete plant pathogen Myrothecium verrucaria (Mv) efficiently catalyses the oxidation of bilirubin to biliverdin, with the concomitant reduction of O(2) to water, a reaction of considerable interest for low-temperature bio-fuel cell applications. We have solved the complete X-ray determined structure of Mv BOx at 2.4 Å resolution, using molecular replacement with the Spore Coat Protein A (CotA) enzyme from Bacillus subtilis (PDB code 1GSK) as a template. The structure reveals an unusual environment around the blue type 1 copper (T1 Cu) that includes two non-coordinating hydrophilic amino acids, asparagine and threonine. The presence of a long, narrow and hydrophilic pocket near the T1 Cu suggests that structure of the substrate-binding site is dynamically determined in vivo. We show that the interaction between the binding pocket of Mv BOx and its highly conjugated natural organic substrate, bilirubin, can be used to stabilise the enzyme on a pyrolytic graphite electrode, more than doubling its electrocatalytic activity relative to the current obtained by simple adsorption of the protein to the carbon surface.

  3. Wavelength-dependence of the relative rate constants for the main geometric and structural photoisomerization of bilirubin IX alpha bound to human serum albumin. Demonstration of green light at 510 nm as the most effective wavelength in photochemical changes from (ZZ)-bilirubin IX alpha to (EZ)-cyclobilirubin IX alpha via (EZ)-bilirubin.

    PubMed Central

    Onishi, S; Itoh, S; Isobe, K

    1986-01-01

    The kinetics for the quantitatively important reaction: (Formula: see text) that is, the photochemical interconversion between bilirubin and its geometric and structural photoisomers bound to human serum albumin in aqueous solution when various wavelengths of monochromatic light were used, were assayed by h.p.l.c. In order to clarify the wavelength-dependence of the relative rate constants in the individual steps, a light-source with a half-bandwidth of 10 nm was used at increments of 20 nm, in the range from 410 nm to 550 nm. We describe for the first time studies on the wavelength-dependence of rate constants in geometric and structural photoisomerization reactions in vitro of (ZZ)-bilirubin or (EZ)-bilirubin bound to human serum albumin, especially the relative rate constants of cyclization of (EZ)-bilirubin into (EZ)-cyclobilirubin. Because studies in vitro have demonstrated that the wavelengths from 350 to 450 nm are mutagenic, the results obtained indicated that the safest and ideal light-source for phototherapy is green light of 510 nm, which keeps (ZE)-bilirubin concentrations as low as possible, as shown by a maximal value of k2 at 510 nm and a relatively low value of k1 at 510 nm. This light-source still ensures the substantial absorption of (ZZ)-bilirubin, which is the precursor of (EZ)-bilirubin, the intermediate in (EZ)-cyclobilirubin formation and, furthermore, as shown by the maximal value of k5 and a considerable value of k4 at 510 nm, promotes the cyclization of (EZ)-bilirubin derived from (ZZ)-bilirubin even though k3 at 510 nm also shows a peak value. PMID:3790073

  4. Electrochemical pretreatment of amino-carbon nanotubes on graphene support as a novel platform for bilirubin oxidase with improved bioelectrocatalytic activity towards oxygen reduction.

    PubMed

    Navaee, Aso; Salimi, Abdollah; Jafari, Fereydoon

    2015-03-23

    The electrochemical conditioning of amino-carbon nanotubes (CNTs) on a graphene support in an alkaline solution is used to produce -NHOH as hydrophilic functional groups for the efficient immobilization of bilirubin oxidase enzyme. The application of the immobilized enzyme for the direct electrocatalytic reduction of O2 is investigated. The onset potential of 0.81 V versus NHE and peak current density of 2.3 mA cm(-2) for rotating modified electrode at 1250 rpm, indicate improved biocatalytic activity of the proposed system for O2 reduction. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Bilirubin inhibits the up-regulation of inducible nitric oxide synthase by scavenging reactive oxygen species generated by the toll-like receptor 4-dependent activation of NADPH oxidase.

    PubMed

    Idelman, Gila; Smith, Darcey L H; Zucker, Stephen D

    2015-08-01

    It has been previously shown that bilirubin prevents the up-regulation of inducible nitric oxide synthase (iNOS) in response to LPS. The present study examines whether this effect is exerted through modulation of Toll-Like Receptor-4 (TLR4) signaling. LPS-stimulated iNOS and NADPH oxidase (Nox) activity in RAW 264.7 murine macrophages was assessed by measuring cellular nitrate and superoxide ( [Formula: see text] ) production, respectively. The generation of both nitrate and [Formula: see text] in response to LPS was suppressed by TLR4 inhibitors, indicating that activation of iNOS and Nox is TLR4-dependent. While treatment with superoxide dismutase (SOD) and bilirubin effectively abolished LPS-mediated [Formula: see text] production, hydrogen peroxide and nitrate release were inhibited by bilirubin and PEG-catalase, but not SOD, supporting that iNOS activation is primarily dependent upon intracellular H2O2. LPS treatment increased nuclear translocation of the redox-sensitive transcription factor Hypoxia Inducible Factor-1α (HIF-1α), an effect that was abolished by bilirubin. Cells transfected with murine iNOS reporter constructs in which the HIF-1α-specific hypoxia response element was disrupted exhibited a blunted response to LPS, supporting that HIF-1α mediates Nox-dependent iNOS expression. Bilirubin, but not SOD, blocked the cellular production of interferon-β, while interleukin-6 production remained unaffected. These data support that bilirubin inhibits the TLR4-mediated up-regulation of iNOS by preventing activation of HIF-1α through scavenging of Nox-derived reactive oxygen species. Bilirubin also suppresses interferon-β release via a ROS-independent mechanism. These findings characterize potential mechanisms for the anti-inflammatory effects of bilirubin.

  6. Integration of Platinum Group Metal-Free Catalysts and Bilirubin Oxidase into a Hybrid Material for Oxygen Reduction: Interplay of Chemistry and Morphology.

    PubMed

    Rojas-Carbonell, Santiago; Babanova, Sofia; Serov, Alexey; Artyushkova, Kateryna; Workman, Michael J; Santoro, Carlo; Mirabal, Alex; Calabrese Barton, Scott; Atanassov, Plamen

    2017-04-10

    Catalytic activity toward the oxygen reduction reaction (ORR) of platinum group metal-free (PGM-free) electrocatalysts integrated with an enzyme (bilirubin oxidase, BOx) in neutral media was studied. The effects of chemical and morphological characteristics of PGM-free materials on the enzyme enhancement of the overall ORR kinetics was investigated. The surface chemistry of the PGM-free catalyst was studied using X-ray Photoelectron Spectroscopy. Catalyst surface morphology was characterized using two independent methods: length-scale specific image analysis and nitrogen adsorption. Good agreement of macroscopic and microscopic morphological properties was found. Enhancement of ORR activity by the enzyme is influenced by chemistry and surface morphology of the catalyst itself. Catalysts with a higher nitrogen content, specifically pyridinic moieties, showed the greatest enhancement. Furthermore, catalysts with a higher fraction of surface roughness in the range of 3-5 nm exhibited greater performance enhancement than catalysts lacking features of this size. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Biofuel cells based on direct enzyme-electrode contacts using PQQ-dependent glucose dehydrogenase/bilirubin oxidase and modified carbon nanotube materials.

    PubMed

    Scherbahn, V; Putze, M T; Dietzel, B; Heinlein, T; Schneider, J J; Lisdat, F

    2014-11-15

    Two types of carbon nanotube electrodes (1) buckypaper (BP) and (2) vertically aligned carbon nanotubes (vaCNT) have been used for elaboration of glucose/O2 enzymatic fuel cells exploiting direct electron transfer. For the anode pyrroloquinoline quinone dependent glucose dehydrogenase ((PQQ)GDH) has been immobilized on [poly(3-aminobenzoic acid-co-2-methoxyaniline-5-sulfonic acid), PABMSA]-modified electrodes. For the cathode bilirubin oxidase (BOD) has been immobilized on PQQ-modified electrodes. PABMSA and PQQ act as promoter for enzyme bioelectrocatalysis. The voltammetric characterization of each electrode shows current densities in the range of 0.7-1.3 mA/cm(2). The BP-based fuel cell exhibits maximal power density of about 107 µW/cm(2) (at 490 mV). The vaCNT-based fuel cell achieves a maximal power density of 122 µW/cm(2) (at 540 mV). Even after three days and several runs of load a power density over 110 µW/cm(2) is retained with the second system (10mM glucose). Due to a better power exhibition and an enhanced stability of the vaCNT-based fuel cells they have been studied in human serum samples and a maximal power density of 41 µW/cm(2) (390 mV) can be achieved. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Spectroscopic and crystallographic characterization of "alternative resting" and "resting oxidized" enzyme forms of bilirubin oxidase: implications for activity and electrochemical behavior of multicopper oxidases.

    PubMed

    Kjaergaard, Christian H; Durand, Fabien; Tasca, Federico; Qayyum, Munzarin F; Kauffmann, Brice; Gounel, Sébastien; Suraniti, Emmanuel; Hodgson, Keith O; Hedman, Britt; Mano, Nicolas; Solomon, Edward I

    2012-03-28

    While there is broad agreement on the catalytic mechanism of multicopper oxidases (MCOs), the geometric and electronic structures of the resting trinuclear Cu cluster have been variable, and their relevance to catalysis has been debated. Here, we present a spectroscopic characterization, complemented by crystallographic data, of two resting forms occurring in the same enzyme and define their interconversion. The resting oxidized form shows similar features to the resting form in Rhus vernicifera and Trametes versicolor laccase, characterized by "normal" type 2 Cu electron paramagnetic resonance (EPR) features, 330 nm absorption shoulder, and a short type 3 (T3) Cu-Cu distance, while the alternative resting form shows unusually small A(||) and high g(||) EPR features, lack of 330 nm absorption intensity, and a long T3 Cu-Cu distance. These different forms are evaluated with respect to activation for catalysis, and it is shown that the alternative resting form can only be activated by low-potential reduction, in contrast to the resting oxidized form which is activated via type 1 Cu at high potential. This difference in activity is correlated to differences in redox states of the two forms and highlights the requirement for efficient sequential reduction of resting MCOs for their involvement in catalysis.

  9. Membraneless enzymatic ethanol/O2 fuel cell: Transitioning from an air-breathing Pt-based cathode to a bilirubin oxidase-based biocathode

    NASA Astrophysics Data System (ADS)

    Aquino Neto, Sidney; Milton, Ross D.; Hickey, David P.; De Andrade, Adalgisa R.; Minteer, Shelley D.

    2016-08-01

    The bioelectrooxidation of ethanol was investigated in a fully enzymatic membraneless ethanol/O2 biofuel cell assembly using hybrid bioanodes containing multi-walled carbon nanotube (MWCNT)-decorated gold metallic nanoparticles with either a pyrroloquinoline quinone (PQQ)-dependent alcohol dehydrogenase (ADH) enzyme or a nicotinamide adenine dinucleotide (NAD+)-dependent ADH enzyme. The biofuel cell anode was prepared with the PQQ-dependent enzyme and designed using either a direct electron transfer (DET) architecture or via a mediated electron transfer (MET) configuration through a redox polymer, 1,1‧-dimethylferrocene-modified linear polyethyleneimine (FcMe2-C3-LPEI). In the case of the bioanode containing the NAD+-dependent enzyme, only the mediated electron transfer mechanism was employed using an electropolymerized methylene green film to regenerate the NAD+ cofactor. Regardless of the enzyme being employed at the anode, a bilirubin oxidase-based biocathode prepared within a DET architecture afforded efficient electrocatalytic oxygen reduction in an ethanol/O2 biofuel cell. The power curves showed that DET-based bioanodes via the PQQ-dependent ADH still lack high current densities, whereas the MET architecture furnished maximum power density values as high as 226 ± 21 μW cm-2. Considering the complete membraneless enzymatic biofuel cell with the NAD+-dependent ADH-based bioanode, power densities as high as 111 ± 14 μW cm-2 were obtained. This shows the advantage of PQQ-dependent ADH for membraneless ethanol/O2 biofuel cell applications.

  10. Point mutations at the type I Cu ligands, Cys457 and Met467, and at the putative proton donor, Asp105, in Myrothecium verrucaria bilirubin oxidase and reactions with dioxygen.

    PubMed

    Kataoka, Kunishige; Kitagawa, Rieko; Inoue, Megumi; Naruse, Daisaku; Sakurai, Takeshi; Huang, Hong-wei

    2005-05-10

    The type I Cu site in the Cys457Ser mutant of Myrothecium verrucaria bilirubin oxidase was vacant, but the trinuclear center composed of a type II Cu and a pair of type III Cu's was fully occupied by three Cu ions. Cys457Ser could react with dioxygen, affording reaction intermediate I with absorption maxima at 340, 470, and 675 nm. This intermediate corresponds to that obtained from laccase, whose type I Cu is cupric and type II and III Cu's are cuprous [Zoppellaro, G., Sakurai, T., and Huang, H. (2001) J. Biochem. 129, 949-953] or whose type I Cu is substituted with Hg [Palmer, A. E., Lee, S. K., and Solomon, E. I. (2001) J. Am. Chem. Soc. 123, 6591-6599]. Another type I Cu mutant, Met467Gln, with modified spectroscopic properties and redox potential, afforded reaction intermediate II with absorption maxima at 355 and 450 nm. This intermediate corresponds to that obtained during the reaction of laccase [Sundaram, U. M., Zhang, H. H., Hedman, B., Hodgson, K. O., and Solomon, E. I. (1997) J. Am. Chem. Soc. 119, 12525-12540; Huang, H., Zoppellaro, G., and Sakurai, T. (1999) J. Biol. Chem. 274, 32718-32724]. According to a three-dimensional model of bilirubin oxidase, Asp105 is positioned near the trinuclear center. Asp105Glu and Asp105Ala exhibited 46 and 7.5% bilirubin oxidase activity compared to the wild-type enzyme, respectively, indicating that Asp105 conserved in all multi-copper oxidases donates a proton to reaction intermediates I and II. In addition, this amino acid might be involved in the formation of the trinuclear center and in the binding of dioxygen based on the difficulties in incorporating four Cu ions in Asp105Ala and Asp105Asn and their reactions with dioxygen.

  11. Bilirubin - urine

    MedlinePlus

    ... may be due to: Biliary tract disease Cirrhosis Gallstones in the biliary tract Hepatitis Liver disease Tumors ... duct stricture Biliary system Bilirubin blood test Cirrhosis Gallstones Hepatitis Liver cancer - hepatocellular carcinoma Review Date 5/ ...

  12. Two-dimensional crystallization of monomeric bovine cytochrome c oxidase with bound cytochrome c in reconstituted lipid membranes.

    PubMed

    Osuda, Yukiho; Shinzawa-Itoh, Kyoko; Tani, Kazutoshi; Maeda, Shintaro; Yoshikawa, Shinya; Tsukihara, Tomitake; Gerle, Christoph

    2016-06-01

    Mitochondrial cytochrome c oxidase utilizes electrons provided by cytochrome c for the active vectorial transport of protons across the inner mitochondrial membrane through the reduction of molecular oxygen to water. Direct structural evidence on the transient cytochrome c oxidase-cytochrome c complex thus far, however, remains elusive and its physiological relevant oligomeric form is unclear. Here, we report on the 2D crystallization of monomeric bovine cytochrome c oxidase with tightly bound cytochrome c at a molar ratio of 1:1 in reconstituted lipid membranes at the basic pH of 8.5 and low ionic strength.

  13. Purification and structural analysis of membrane-bound polyphenol oxidase from Fuji apple.

    PubMed

    Liu, Fang; Zhao, Jin-Hong; Wen, Xin; Ni, Yuan-Ying

    2015-09-15

    Membrane-bound polyphenol oxidase (mPPO) in Fuji apple (Malus domestica Borkh. cv. Red Fuji) was purified and analyzed with a nanoelectrospray ionization mass spectrometer. The three-dimensional model and binding site of mPPO to 4-methyl catechol were also studied using molecular docking. mPPO was purified 54.41-fold using temperature-induced phase partitioning technique and ion exchange chromatography. mPPO had a molecular weight of 67.3kDa. Even though a significant level of homology was observed between mPPO and the soluble polyphenol oxidase in the copper binding sequence, there was another region, rich in histidine residues, which differed in 13 amino acids. The three-dimensional structure of mPPO consisted of six α-helices, two short β-strands, and ten random coils. The putative substrate-binding pocket contained six polar or charged amino acids, His191, His221, Trp224, Trp228, Phe227, and Val190. Trp224 and Trp228 formed hydrogen bonds with 4-methyl-catechol.

  14. First Observation Of The Wavelength-Dependent Photoproduction Of The 4E,15Z Configurational Isomer Of Bilirubin Bound To Human Serum Albumin

    NASA Astrophysics Data System (ADS)

    Mc Donagh, Antony F.; Agati, Giovanni; Fusi, Franco; Pratesi, R.

    1987-07-01

    The photochemistry of bilirubin (BR) is of considerable interest because of its importance in the treatment of neonatal jaundice with visible light phototherapy. Patients are irradiated with blue, white or green fluorescent lamps to induce conversion of the unexcretable and toxic bilirubin to more polar, water-soluble and easily excreted photoproducts. The molecular mechanisms responsible for the phototherapeutic action of light on jaundiced babies have not jet been completely elucidated.

  15. Bilirubin Blood Test

    MedlinePlus

    ... precaution. Why do I need a bilirubin blood test? Your health care provider may order a bilirubin blood test: If ... hemolytic anemia What happens during a bilirubin blood test? A health care professional will take a blood sample from a ...

  16. The Kinetic Stability of Cytochrome c Oxidase: Effect of Bound Phospholipid and Dimerization

    PubMed Central

    Sedlák, Erik; Varhač, Rastislav; Musatov, Andrej; Robinson, Neal C.

    2014-01-01

    Thermally induced transitions of the 13-subunit integral membrane protein bovine cytochrome c oxidase (CcO) have been studied by differential scanning calorimetry (DSC) and circular dichroism (CD). Thermal denaturation of dodecyl maltoside solubilized CcO proceeds in two consecutive, irreversible, kinetically driven steps with the apparent transition temperatures at ∼ 51°C and ∼ 61°C (5μM CcO at scan rate of 1.5 K/min). The thermal denaturation data were analyzed according to the Lyubarev and Kurganov model of two consecutive irreversible steps. However, because of the limitation of the model to describe the complex mechanism of the thermal denaturation of CcO, the obtained results were utilized only for comparison purposes of kinetic stabilities of CcO under specific protein concentration (5μM) and scan rate (1.5 K/min). This enabled us to show that both the amphiphilic environment and the self-association state of CcO affect its kinetic stability. Kinetic stabilities of both steps are significantly decreased when all of the phospholipids are removed from CcO by phospholipase A2 (the half-life decreases at 37°C). Conversely, dimerization of CcO induced by sodium cholate significantly increases its kinetic stability of only the first step (the half-life increases at 37°C). Protein concentration-dependent nonspecific oligomerization also indicate mild stabilization of CcO. Both, reversed-phase high-performance liquid chromatography (HPLC) and SDS-PAGE subunit analysis reveal that the first step of thermal denaturation involves dissociation of subunits III, VIa, VIb, and VIIa, whereas the second step is less well defined and most likely involves global unfold and aggregation of the remaining subunits. Electron transport activity of CcO decreases in a sigmoidal manner during the first transition and this dependence is very well described by kinetic parameters for the first step of the thermal transition. Therefore, dissociation of subunit III and/or VIIa is

  17. Blood Test: Bilirubin

    MedlinePlus

    ... Your 1- to 2-Year-Old Blood Test: Bilirubin KidsHealth > For Parents > Blood Test: Bilirubin A A A What's in this article? What ... Análisis de sangre: bilirrubina What It Is A bilirubin test measures the level of bilirubin (a byproduct ...

  18. Immobilization of bilirubin oxidase on graphene oxide flakes with different negative charge density for oxygen reduction. The effect of GO charge density on enzyme coverage, electron transfer rate and current density.

    PubMed

    Filip, Jaroslav; Andicsová-Eckstein, Anita; Vikartovská, Alica; Tkac, Jan

    2017-03-15

    Previously we showed that an effective bilirubin oxidase (BOD)-based biocathode using graphene oxide (GO) could be prepared in 2 steps: 1. electrostatic adsorption of BOD on GO; 2. electrochemical reduction of the BOD-GO composite to form a BOD-ErGO (electrochemically reduced GO) film on the electrode. In order to identify an optimal charge density of GO for BOD-ErGO composite preparation, several GO fractions differing in an average flake size and ζ-potential were prepared using centrifugation and consequently employed for BOD-ErGO biocathode preparation. A simple way to express surface charge density of these particular GO nanosheets was developed. The values obtained were then correlated with biocatalytic and electrochemical parameters of the prepared biocathodes, i.e. electrocatalytically active BOD surface coverage (Γ), heterogeneous electron transfer rate (kS) and a maximum biocatalytic current density. The highest bioelectrocatalytic current density of (597±25)μAcm(-2) and the highest Γ of (23.6±0.9)pmolcm(-2) were obtained on BOD-GO composite having the same moderate negative charge density, but the highest kS of (79.4±4.6)s(-1) was observed on BOD-GO composite having different negative charge density. This study is a solid foundation for others to consider the influence of a charge density of GO on direct bioelectrochemistry/bioelectrocatalysis of other redox enzymes applicable for construction of biosensors, bioanodes, biocathodes or biofuel cells.

  19. Fluorescent protein-based detection of unconjugated bilirubin in newborn serum

    PubMed Central

    Iwatani, Sota; Nakamura, Hajime; Kurokawa, Daisuke; Yamana, Keiji; Nishida, Kosuke; Fukushima, Sachiyo; Koda, Tsubasa; Nishimura, Noriyuki; Nishio, Hisahide; Iijima, Kazumoto; Miyawaki, Atsushi; Morioka, Ichiro

    2016-01-01

    Increased serum levels of unconjugated bilirubin are associated with the development of brain damage in newborns. In current clinical settings, there are no methods for directly determining serum levels of unconjugated bilirubin. UnaG, a fluorescent protein from Japanese eel muscle that specifically binds to unconjugated bilirubin was used in this study. Linear regression analysis was carried out to compare unconjugated bilirubin levels measured by UnaG and conventional bilirubin oxidase methods. Unconjugated bilirubin levels in the serum of newborns who were untreated or treated with phototherapy were compared. Effects of interfering factors in the serum (conjugated bilirubin, hemoglobin, and lipid) on unconjugated bilirubin concentration measured by the UnaG method were also evaluated. Unconjugated bilirubin levels measured by the UnaG method were highly correlated with those determined by the bilirubin oxidase assay. Unconjugated bilirubin levels determined by bilirubin oxidase and UnaG assays were similar in serum samples containing conjugated bilirubin. The performance of the UnaG assay was unaffected by phototherapy and the presence of serum hemoglobin and lipid emulsion. These results demonstrate the clinical applicability of the UnaG method for direct measurement of unconjugated bilirubin levels in newborn serum. PMID:27324682

  20. Blood Test: Bilirubin

    MedlinePlus

    ... two forms in the body: indirect (unconjugated) and direct (conjugated). Indirect bilirubin, which doesn't dissolve in ... liver to be changed into the soluble form, direct bilirubin. Why It's Done Healthy newborns — especially those ...

  1. Construction of an amperometric ascorbate biosensor using epoxy resin membrane bound Lagenaria siceraria fruit ascorbate oxidase.

    PubMed

    Pundir, C S; Chauhan, Nidhi; Jyoti

    2011-06-01

    Ascorbate oxidase purified from Lagenaria siceraria fruit was immobilized onto epoxy resin "Araldite" membrane with 79.4% retention of initial activity of free enzyme. The biosensor showed optimum response within 15s at pH 5.8 and 35°C, which was directly proportional to ascorbate concentration ranging from 1-100μM. There was a good correlation (R(2) = 0.99) between serum ascorbic acid values by standard enzymic colorimetric method and the present method. The enzyme electrode was used for 200 times without considerable loss of activity during the span of 90 days when stored at 4°C.

  2. pH-induced kinetic co-operativity of a thylakoid-bound polyphenol oxidase.

    PubMed Central

    Valero, E; García-Carmona, F

    1992-01-01

    A study of the catecholase activity of a latent plant polyphenol oxidase, extracted and purified from the chloroplast membranes of grapes (Vitis vinifera cv. Airen), revealed for the first time a lag phase above pH 5.0, whereas a steady-state rate was reached immediately when pH values were lower, thus suggesting the hysteretic nature of the enzyme. During steady state, the enzyme showed negative co-operativity concomitant with the presence of the lag period, and followed classical Michaelis-Menten kinetics under more acid pH conditions. Statistical analysis of these data showed a minimal value for the extreme Hill coefficient of 0.54 at pH 6.0. This kinetic behaviour of polyphenol oxidase has been interpreted in terms of the pH-induced 'slow' transition mechanism reported by Ricard, Noat & Nari [(1984) Eur. J. Biochem. 145, 311-317] in which the conformational change does not affect the active site of the enzyme. Images Fig. 4. PMID:1530593

  3. Enzymic oxidation of unconjugated bilirubin by rat liver.

    PubMed Central

    Cardenas-Vazquez, R; Yokosuka, O; Billing, B H

    1986-01-01

    The presence of the enzyme bilirubin oxidase, which degrades bilirubin in vitro, was demonstrated in the liver. Subcellular-fractionation experiments indicate that bilirubin oxidase is located in both the inner and outer membranes of the mitochondria. The mean rate of the reaction is 1.57 +/- 0.38 (S.D.) nmol of bilirubin degraded/min per mg of mitochondrial protein (munits/mg of protein). With respect to the overall breakdown of bilirubin, the enzyme has a Km' of 136 microM-bilirubin and a Vmax.' of 9.13 munits/mg of protein. Its activity is influenced by the ionic strength of the media and is inhibited by KCN, thiol reagents, NADH and albumin. The enzyme is aerobic, and between 1 and 1.5 mol of O2 are consumed per mol of bilirubin degraded. The products of the reaction include propentdyopents. The hepatic bilirubin oxidase activity of the jaundiced Gunn-rat liver is not significantly different from that of the Sprague-Dawley rat, and it is not induced by beta-naphthoflavone. PMID:3790083

  4. An amperometric cholesterol biosensor based on epoxy resin membrane bound cholesterol oxidase

    PubMed Central

    Pundir, C.S.; Narang, Jagriti; Chauhan, Nidhi; Sharma, Preety; Sharma, Renu

    2012-01-01

    Background & objectives: The use of epoxy resin membrane as a support for immobilization of enzyme has resulted into improved sensitivity and stability of biosensors for uric acid, ascorbic acid and polyphenols. The present work was aimed to prepare an improved amperometric biosensor for determination of serum cholesterol required in the diagnostics and management of certain pathological conditions. Methods: Epoxy resin membrane with immobilized cholesterol oxidase was mounted on the cleaned platinum (Pt) electrode with a parafilm to construct a working electrode. This working electrode along with Ag/AgCl as reference and Ag wire as an auxiliary electrode were connected through a three terminal electrometer to construct a cholesterol biosensor. Results: The sensor showed optimum response within 25 sec at pH 7.0 and 45°C. The linear working range of biosensor was 1.0 to 8.0 mM cholesterol. Km and Imax for cholesterol were 5.0 mM and 9.09 μA, respectively. The biosensor measured serum cholesterol. The minimum detection limit of the sensor was 1.0 mM. The mean analytical recoveries of added cholesterol in serum (2.84 and 4.13 mM) were 91.4±2.8 and 92.3±3.1 per cent (n=6), respectively. Within and between assay coefficient of variation (CV) were <2 and <4 per cent, respectively. Biosensor had a storage life of 6 months at 4°C. Interpretation & conclusions: The use of epoxy resin membrane as a support for immobilization of cholesterol oxidase has resulted into an improved amperometric cholesterol biosensor. The present biosensor had an advantage over the existing biosensors as it worked at comparatively lower potential. PMID:23168704

  5. An amperometric cholesterol biosensor based on epoxy resin membrane bound cholesterol oxidase.

    PubMed

    Pundir, C S; Narang, Jagriti; Chauhan, Nidhi; Sharma, Preety; Sharma, Renu

    2012-10-01

    The use of epoxy resin membrane as a support for immobilization of enzyme has resulted into improved sensitivity and stability of biosensors for uric acid, ascorbic acid and polyphenols. The present work was aimed to prepare an improved amperometric biosensor for determination of serum cholesterol required in the diagnostics and management of certain pathological conditions. Epoxy resin membrane with immobilized cholesterol oxidase was mounted on the cleaned platinum (Pt) electrode with a parafilm to construct a working electrode. This working electrode along with Ag/AgCl as reference and Ag wire as an auxiliary electrode were connected through a three terminal electrometer to construct a cholesterol biosensor. The sensor showed optimum response within 25 sec at pH 7.0 and 45°C. The linear working range of biosensor was 1.0 to 8.0 mM cholesterol. K m and I max for cholesterol were 5.0 mM and 9.09 μA, respectively. The biosensor measured serum cholesterol. The minimum detection limit of the sensor was 1.0 mM. The mean analytical recoveries of added cholesterol in serum (2.84 and 4.13 mM) were 91.4 ± 2.8 and 92.3 ± 3.1 per cent (n=6), respectively. Within and between assay coefficient of variation (CV) were <2 and <4 per cent, respectively. Biosensor had a storage life of 6 months at 4 o C. The use of epoxy resin membrane as a support for immobilization of cholesterol oxidase has resulted into an improved amperometric cholesterol biosensor. The present biosensor had an advantage over the existing biosensors as it worked at comparatively lower potential.

  6. X-ray structure of cyanide-bound bovine heart cytochrome c oxidase in the fully oxidized state at 2.0 Å resolution.

    PubMed

    Yano, Naomine; Muramoto, Kazumasa; Mochizuki, Masao; Shinzawa-Itoh, Kyoko; Yamashita, Eiki; Yoshikawa, Shinya; Tsukihara, Tomitake

    2015-06-01

    The X-ray structure of cyanide-bound bovine heart cytochrome c oxidase in the fully oxidized state was determined at 2.0 Å resolution. The structure reveals that the peroxide that bridges the two metals in the fully oxidized state is replaced by a cyanide ion bound in a nearly symmetric end-on fashion without significantly changing the protein conformation outside the two metal sites.

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

    NASA Astrophysics Data System (ADS)

    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.

  8. An antibody that confers plant disease resistance targets a membrane-bound glyoxal oxidase in Fusarium.

    PubMed

    Song, Xiu-Shi; Xing, Shu; Li, He-Ping; Zhang, Jing-Bo; Qu, Bo; Jiang, Jin-He; Fan, Chao; Yang, Peng; Liu, Jin-Long; Hu, Zu-Quan; Xue, Sheng; Liao, Yu-Cai

    2016-05-01

    Plant germplasm resources with natural resistance against globally important toxigenic Fusarium are inadequate. CWP2, a Fusarium genus-specific antibody, confers durable resistance to different Fusarium pathogens that infect cereals and other crops, producing mycotoxins. However, the nature of the CWP2 target is not known. Thus, investigation of the gene coding for the CWP2 antibody target will likely provide critical insights into the mechanism underlying the resistance mediated by this disease-resistance antibody. Immunoblots and mass spectrometry analysis of two-dimensional electrophoresis gels containing cell wall proteins from Fusarium graminearum (Fg) revealed that a glyoxal oxidase (GLX) is the CWP2 antigen. Cellular localization studies showed that GLX is localized to the plasma membrane. This GLX efficiently catalyzes hydrogen peroxide production; this enzymatic activity was specifically inhibited by the CWP2 antibody. GLX-deletion strains of Fg, F. verticillioides (Fv) and F. oxysporum had significantly reduced virulence on plants. The GLX-deletion Fg and Fv strains had markedly reduced mycotoxin accumulation, and the expression of key genes in mycotoxin metabolism was downregulated. This study reveals a single gene-encoded and highly conserved cellular surface antigen that is specifically recognized by the disease-resistance antibody CWP2 and regulates both virulence and mycotoxin biosynthesis in Fusarium species.

  9. Role of human skin in the photodecomposition of bilirubin

    PubMed Central

    Kapoor, Chiranjiv L.; Murti, Coimbatore R. Krishna; Bajpai, Prakash C.

    1974-01-01

    1. Human skin epithelium and human skin were found to absorb both free bilirubin and serum-bound bilirubin from an aqueous buffered medium. The serum-bound bilirubin thus absorbed was readily released when human skin epithelium or human skin were transferred to media containing no bilirubin. 2. The Km values for serum-bound bilirubin were 1.8×10−3m and 2.2×10−3m respectively for human skin epithelium and human skin; corresponding Km values for free bilirubin were 3.0×10−4m and 5×10−4m. The Vmax. for bound and free bilirubin was of the same magnitude, the apparent Vmax. being 1.0 and 1.66μmol/g of tissue for human skin epithelium and human skin respectively. 3. When human skin that had acquired a yellow tinge by absorbing bilirubin was incubated in a buffered medium and exposed to a mercury-vapour light, the yellow colour disappeared and decomposition products of bilirubin accumulated in the medium. 4. Experiments with [3H]bilirubin indicated that the pigment absorbed by skin was photo-oxidized to products that were soluble in water and the quantity and number of such products increased with the time of exposure of human skin to the light-source. Under similar conditions [3H]bilirubin alone in buffered medium was also oxidized and gave products which by paper chromatography appeared to be different from those released by human skin that had absorbed bilirubin. 5. The results suggest that by virtue of its large surface area human skin can act as a matrix for the degradative action of light on bilirubin. PMID:4464841

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

    PubMed

    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 (BTotal), which is currently used to guide clinical care; the bilirubin binding capacity (BBC); and the concentration of non-albumin bound or free bilirubin (BFree). The fourth component is the bilirubin-albumin equilibrium dissociation constant, KD, which is calculated from BTotal, BBC, and BFree 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 BTotal) are needed to expedite the clinical use of bilirubin binding. At any BTotal, the BFree and the relative risk of bilirubin neurotoxicity increase as the KD/BBC ratio increases (ie, bilirubin binding worsens). Comparing the KD/BBC ratio of newborns with BTotal of concern with that typical for the population helps determine whether the risk of bilirubin neurotoxicity varies significantly from the inherent risk at that BTotal Furthermore, the bilirubin binding panel individualizes care because it helps to determine how aggressive intervention should be at any BTotal, irrespective of whether it is above or below established BTotal guidelines. The bilirubin binding panel may reduce anxiety, costs, unnecessary treatment, and the likelihood of undetected bilirubin neurotoxicity.

  11. Biology of Bilirubin Photoisomers.

    PubMed

    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.

  12. Reconstitution of the membrane-bound, ubiquinone-dependent pyruvate oxidase respiratory chain of Escherichia coli with the cytochrome d terminal oxidase

    SciTech Connect

    Koland, J.G.; Miller, M.J.; Gennis, R.B.

    1984-01-31

    Pyruvate oxidase is a flavoprotein dehydrogenase located on the inner surface of the Escherichia coli cytoplasmic membrane and coupled to the E. coli aerobic respiratory chain. The role of quinones in the pyruvate oxidase system is investigated, and a minimal respiratory chain is described consisting of only two pure proteins plus ubiquinone 8 incorporated in phospholipid vesicles. The enzymes used in this reconstitution are the flavorprotein and the recently purified E. coli cytochrome d terminal oxidase. The catalytic velocity of the reconstituted liposome system is about 30% of that observed when the flavoprotein is reconstituted with E. coli membranes. It is also shown that electron transport from pyruvate to oxygen in the liposome system generates a transmembrane potential of at least 180 mV (negative inside), which is sensitive to the uncouplers carbonyl cyanide p-(trichloromethoxy)phenylhydrazone and valinomycin. A transmembrane potential is also generated by the oxidation of ubiquinol 1 by the terminal oxidase in the absence of the flavoprotein. It is concluded that: the flavoprotein can directly reduce ubiquinone 8 within the phospholipid bilayer; menaquinone 8 will not effectively substitute for ubiquinone 8 in this electron-transfer chain; and the cytochrome d terminal oxidase functions as a ubiquinol 8 oxidase and serves as a coupling site in the E. coli aerobic respiratory chain. These investigations suggest a relatively simple organization for the E. coli respiratory chain.

  13. Reconstitution of the membrane-bound, ubiquinone-dependent pyruvate oxidase respiratory chain of Escherichia coli with the cytochrome d terminal oxidase.

    PubMed

    Koland, J G; Miller, M J; Gennis, R B

    1984-01-31

    Pyruvate oxidase is a flavoprotein dehydrogenase located on the inner surface of the Escherichia coli cytoplasmic membrane and coupled to the E. coli aerobic respiratory chain. In this paper, the role of quinones in the pyruvate oxidase system is investigated, and a minimal respiratory chain is described consisting of only two pure proteins plus ubiquinone 8 incorporated in phospholipid vesicles. The enzymes used in this reconstitution are the flavoprotein and the recently purified E. coli cytochrome d terminal oxidase. The catalytic velocity of the reconstituted liposome system is about 30% of that observed when the flavoprotein is reconstituted with E. coli membranes. It is also shown that electron transport from pyruvate to oxygen in the liposome system generates a transmembrane potential of at least 180 mV (negative inside), which is sensitive to the uncouplers carbonyl cyanide p-(tri-chloromethoxy)phenylhydrazone and valinomycin. A trans-membrane potential is also generated by the oxidation of ubiquinol 1 by the terminal oxidase in the absence of the flavoprotein. It is concluded that (1) the flavoprotein can directly reduce ubiquinone 8 within the phospholipid bilayer, (2) menaquinone 8 will not effectively substitute for ubiquinone 8 in this electron-transfer chain, and (3) the cytochrome d terminal oxidase functions as a ubiquinol 8 oxidase and serves as a "coupling site" in the E. coli aerobic respiratory chain. These investigations suggest a relatively simple organization for the E. coli respiratory chain.

  14. Bilirubin oxidation in brain.

    PubMed

    Hansen, T W

    2000-01-01

    Bilirubin is a product of heme catabolism which by virtue of its lipid solubility can cross the blood-brain barrier and enter the brain. Neonatal jaundice is a common transitional phenomenon which is due to the combination of increased heme catabolism and rate limitations as far as hepatic conjugation and biliary excretion of bilirubin. In the great majority of cases this is an innocuous condition, which is even posited to have some beneficial effects due to the ability of bilirubin to quench free oxygen radicals. However, because bilirubin is neurotoxic, hyperbilirubinemia in the newborn may exceptionally result in death in the neonatal period, or survival with severe neurological sequelae (kernicterus). Bilirubin enters the brain through an intact blood-brain barrier. Clearance of bilirubin from brain partly involves retro-transfer through the blood-brain barrier, and possibly also through the brain-CSF barrier into CSF. Work in our lab during the past 5 years has substantiated earlier work which had suggested that bilirubin may also be metabolized in brain. The responsible enzyme is found on the inner mitochondrial membrane, and oxidizes bilirubin at a rate of 100-300 pmol bilirubin/mg protein/minute. The enzyme activity is lower in the newborn compared with the mature animal, and is also lower in neurons compared with glia. Studies of different rat strains have documented genetic variability. The enzyme is cytochrome-c-dependent, but has as yet not been unequivocally identified. The rate of oxidation of bilirubin is such that this enzyme probably contributes meaningfully to the clearance of bilirubin from brain.

  15. Comparison of membrane-bound and soluble polyphenol oxidase in Fuji apple (Malus domestica Borkh. cv. Red Fuji).

    PubMed

    Liu, Fang; Zhao, Jin-Hong; Gan, Zhi-Lin; Ni, Yuan-Ying

    2015-04-15

    This study compared membrane-bound with soluble polyphenol oxidase (mPPO and sPPO, respectively) from Fuji apple. Purified mPPO and partially purified sPPO were used. mPPO was purified by temperature-induced phase partitioning and ion exchange chromatography. The specific activity of mPPO was 34.12× higher than that of sPPO. mPPO was more stable than sPPO at pH 5.0-8.5. Although mPPO was more easily inactivated at 25-55 °C, it is still more active than sPPO in this temperature range. The optimum substrate of mPPO was 4-methyl catechol, followed by catechol. L-cysteine had the highest inhibitory effects on mPPO followed by ascorbic acid and glutathione. Surprisingly, EDTA increased mPPO activity. The results revealed that purified mPPO is a dimer with a molecular weight of approximately 67 kDa.

  16. Polyphenol Oxidation by Vicia faba Chloroplast Membranes: STUDIES ON THE LATENT MEMBRANE-BOUND POLYPHENOL OXIDASE AND ON THE MECHANISM OF PHOTOCHEMICAL POLYPHENOL OXIDATION.

    PubMed

    Hutcheson, S W; Buchanan, B B

    1980-12-01

    The mechanism whereby light effects polyphenol oxidation was examined with Vicia faba chloroplast membranes known to contain a bound latent polyphenol oxidase. Results obtained with the inhibitors 3-(3',4'-dichlorophenyl)-1,1-dimethylurea (DCMU) and 2,5-dibromo-3-methyl-6-idopropyl-p-benzoquinone (DBMIB) indicated an involvement of the non-cyclic electron transport pathway in the light-dependent oxidation of polyphenols, such as dihydroxyphenylalanine (DOPA). Further evidence was provided by experiments in which (a) DOPA replaced H(2)O as electron donor for the photoreduction of NADP, (b) NADP replaced O(2) as electron acceptor in the photochemical oxidation of DOPA, and (c) the variable fluorescence associated with photosystem II was increased by DOPA. The photochemical oxidation of DOPA by V. faba chloroplast membranes was insensitive to KCN and to antibodies against purified latent polyphenol oxidase. The results are consistent with the conclusion that the light-dependent oxidation of polyphenols by V. faba chloroplast membranes is achieved independently of the latent membrane-bound polyphenol oxidase. Electrons derived from polyphenols seem to enter the noncyclic electron transport chain on the oxidizing side of photosystem II and to react with O(2) at an unidentified site on the photosystem I side of the DCMU/DBMIB blocks.The physiological mechanism for the activation of latent polyphenol oxidase remains an unanswered question. Present results suggest that activation could occur through either acidification or the release of free fatty acids.

  17. Crystal structure of CO-bound cytochrome c oxidase determined by serial femtosecond X-ray crystallography at room temperature

    DOE PAGES

    Ishigami, Izumi; Zatsepin, Nadia A.; Hikita, Masahide; ...

    2017-07-11

    Here, cytochrome c oxidase (CcO), the terminal enzyme in the electron transfer chain, translocates protons across the inner mitochondrial membrane by harnessing the free energy generated by the reduction of oxygen to water. Several redox-coupled proton translocation mechanisms have been proposed, but they lack confirmation, in part from the absence of reliable structural information due to radiation damage artifacts caused by the intense synchrotron radiation. Here we report the room temperature, neutral pH (6.8), damage-free structure of bovine CcO (bCcO) in the carbon monoxide (CO)-bound state at a resolution of 2.3 Å, obtained by serial femtosecond X-ray crystallography (SFX) withmore » an X-ray free electron laser. As a comparison, an equivalent structure was obtained at a resolution of 1.95 Å, from data collected at a synchrotron light source. In the SFX structure, the CO is coordinated to the heme a3 iron atom, with a bent Fe–C–O angle of ~142°. In contrast, in the synchrotron structure, the Fe–CO bond is cleaved; CO relocates to a new site near CuB, which, in turn, moves closer to the heme a3 iron by ~0.38 Å. Structural comparison reveals that ligand binding to the heme a3 iron in the SFX structure is associated with an allosteric structural transition, involving partial unwinding of the helix-X between heme a and a3, thereby establishing a communication linkage between the two heme groups, setting the stage for proton translocation during the ensuing redox chemistry.« less

  18. Formation of bilirubin glucoside

    PubMed Central

    Wong, Kim Ping

    1971-01-01

    1. Rat liver microsomal preparation can effect the transglucosylation from UDP-glucose to bilirubin in the presence of Mg2+. 2. Other nucleotides, namely CDP-glucose, ADP-glucose and GDP-glucose, were not active as glucosyl donors. 3. Only trace amounts of galactose, galacturonic acid and N-acetylglucosamine were conjugated to bilirubin when their respective UDP derivatives were used in the reaction mixture. 4. The azobilirubin glucosides produced by coupling with p-diazobenzenesulphonic acid and diazotized ethyl anthranilic acid were separable from the corresponding azobilirubin glucuronides by t.l.c. 5. The glucoside was, however, hydrolysed by both β-glucosidase and various preparations of β-glucuronidase; azobilirubin and glucose were liberated in the process. 6. Kinetic studies showed that the effects of pH and Mg2+ on the two conjugating systems were similar. 7. The specific activities of hepatic bilirubin UDP-glucosyltransferase, expressed as μg of bilirubin `equivalents' conjugated/h per mg of protein, are respectively 1.7 and 2.4 for male and female rats. 8. The Km values for bilirubin and UDP-glucose are 5.7×10−5m and 1.6×10−3m respectively. 9. The glucoside and glucuronide conjugations of bilirubin are discussed in relation to the availability of the conjugating agents and aglycone in the liver. ImagesFig. 1. PMID:5144254

  19. Optical transcutaneous bilirubin detector

    DOEpatents

    Kronberg, J.W.

    1993-11-09

    A transcutaneous bilirubin detector is designed comprising a source of light having spectral components absorbable and not absorbable by bilirubin, a handle assembly, electronic circuitry and a fiber optic bundle connecting the assembly to the light source and circuitry. Inside the assembly is a prism that receives the light from one end of the fiber optic bundle and directs it onto the skin and directs the reflected light back into the bundle. The other end of the bundle is trifucated, with one end going to the light source and the other two ends going to circuitry that determines how much light of each kind has been reflected. A relatively greater amount absorbed by the skin from the portion of the spectrum absorbable by bilirubin may indicate the presence of the illness. Preferably, two measurements are made, one on the kneecap and one on the forehead, and compared to determine the presence of bilirubin. To reduce the impact of light absorption by hemoglobin in the blood carried by the skin, pressure is applied with a plunger and spring in the handle assembly, the pressure limited by points of a button slidably carried in the assembly that are perceived by touch when the pressure applied is sufficient. 6 figures.

  20. Optical transcutaneous bilirubin detector

    DOEpatents

    Kronberg, James W.

    1993-01-01

    A transcutaneous bilirubin detector comprising a source of light having spectral components absorbable and not absorbable by bilirubin, a handle assembly, electronic circuitry and a fiber optic bundle connecting the assembly to the light source and circuitry. Inside the assembly is a prism that receives the light from one end of the fiber optic bundle and directs it onto the skin and directs the reflected light back into the bundle. The other end of the bundle is trifucated, with one end going to the light source and the other two ends going to circuitry that determines how much light of each kind has been reflected. A relatively greater amount absorbed by the skin from the portion of the spectrum absorbable by bilirubin may indicate the presence of the illness. Preferably, two measurements are made, one on the kneecap and one on the forehead, and compared to determine the presence of bilirubin. To reduce the impact of light absorption by hemoglobin in the blood carried by the skin, pressure is applied with a plunger and spring in the handle assembly, the pressure limited by points of a button slidably carried in the assembly that are perceived by touch when the pressure applied is sufficient.

  1. Optical transcutaneous bilirubin detector

    DOEpatents

    Kronberg, J.W.

    1991-03-04

    This invention consists of a transcutaneous bilirubin detector comprising a source of light having spectral components absorbable and not absorbable by bilirubin, a handle assembly, electronic circuitry and a fiber optic bundle connecting the assembly to the light source and circuitry. Inside the assembly is a prism that receives the light from one end of the fiber optic bundle and directs it onto the skin and directs the reflected light back into the bundle. The other end of the bundle is trifucated, with one end going to the light source and the other two ends going to circuitry that determines how much light of each kind has been reflected. A relatively greater amount absorbed by the skin from the portion of the spectrum absorbable by bilirubin may indicate the presence of the illness. Preferably, two measurements are made, one on the kneecap and one on the forehead, and compared to determine the presence of bilirubin. To reduce the impact of light absorption by hemoglobin in the blood carried by the skin, pressure is applied with a plunger and spring in the handle assembly, the pressure limited by points of a button slidably carried in the assembly that are perceived by touch when the pressure applied is sufficient.

  2. Evolution of protein bound Maillard reaction end-products and free Amadori compounds in low lactose milk in presence of fructosamine oxidase I.

    PubMed

    Troise, Antonio Dario; Buonanno, Martina; Fiore, Alberto; Monti, Simona Maria; Fogliano, Vincenzo

    2016-12-01

    Thermal treatments and storage influence milk quality, particularly in low lactose milk as the higher concentration of reducing sugars can lead to the increased formation of the Maillard reaction products (MRPs). The control of the Amadori products (APs) formation is the key step to mitigate the Maillard reaction (MR) in milk. The use of fructosamine oxidases, (Faox) provided promising results. In this paper, the effects of Faox I were evaluated by monitoring the concentration of free and bound MRPs in low lactose milk during shelf life. Results showed that the enzyme reduced the formation of protein-bound MRPs down to 79% after six days at 37°C. Faox I lowered the glycation of almost all the free amino acids resulting effective on basic and polar amino acids. Data here reported corroborate previous findings on the potentiality of Faox enzymes in controlling the early stage of the MR in foods. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Studies on the molecular significance in the interaction of bilirubin with collagen.

    PubMed

    Nagarajan, Usharani; Gladstone Christopher, Jayakumar; Chandrasekaran, Bangaru; Jonnalagadda, Raghava Rao; Balachandran, Unni Nair; Kohsaku, Kawakami

    2013-10-01

    The present investigation is aimed to understand the physiological significance of bilirubin interaction with collagen. In human skin, collagen absorbs both free bilirubin and serum bound bilirubin from the human system. Interaction between bilirubin and collagen depends on time, temperature and concentration of bilirubin. There is an increase in the aggregation rate of collagen in the presence of biliruibin. At physiological condition, 125 nM of bilirubin is the maximum concentration absorbed by per mg of collagen molecule. Bilirubin accelerates the lateral growth of collagen fibrils by shifting its rate of nucleation. Moreover, collagen-bilirubin complex exhibit a tendency to undergo adsorption onto the surface of the fibroblast cells, showing detrimental effects on fibroblasts proliferations. Based on the collagen binding assays, the binding of bilirubin to collagen is found to be electrostatic in nature, which confirms binding between the amino acid fragment of α1 (I) region of collagen and carboxyl group of bilirubin. The biotinylated bilirubin derivatives show better binding to α1 (I) chain rather than α2 (I) chains which clearly designates that bilirubin shows greater affinity to α1 chains of collagen. This novel approach directs to reduce the occurrence of bilirubin in hyperbilirubinemia patients.

  4. Bilirubin measurements in neonates

    NASA Astrophysics Data System (ADS)

    Newman, Gregory J.

    2000-04-01

    Infant Jaundice is a physiologic condition of elevated bilirubin in the tissue that affects nearly 60 percent of all term newborns and virtually 100 percent of premature infants. The high production of bilirubin in the newborn circulatory system and the inability of the immature liver to process and eliminate it case the condition. When the bilirubin levels rise, it starts to deposit in the baby's skin and in the brain. The deposits in the brain can cause neurologic impairment and death. The BiliCheck is a handheld, battery-powered device that measures the level of jaundice non-invasively using BioPhotonics at the point of care. The result is displayed on an LCD screen immediately, so physicians can now make treatment decision without waiting for results to return from the lab. The BiliCheck System has been marketed worldwide since April of 1998 and has received FDA clearance for use in the USA on pre-photo therapy infants in March of 1999.

  5. Ascorbate-synthesizing system in rat liver microsomes. II. A peptide-bound flavin as the prosthetic group of L-gulono-gamma-lactone oxidase.

    PubMed

    Nakagawa, H; Asano, A; Sato, R

    1975-01-01

    L-Gulono-gamma-lactone oxidase [EC 1.1.3.8] was purified 80-fold from rat liver microsomes. In confirmation of our previous finding with a cruder preparation, the purified enzyme was shown to contain an L-gulono-gamma-lactone-reducible pigment as a prosthetic group. This pigment was not liberated from the protein by acid ammonium sulfate, 10% trichloroacetic acid or 2 M area, but was effectively released by proteolytic digestion. The pigment thus released showed a reduced-minus-oxidized difference spectrum characteristic of a flavin compound. The pigment was liberated from a trichloroacetic acid-treated preparation of the enzyme by pronase digestion and purified by Florisil column chromatography and paper chromatography. The absorption spectrum as well as the fluorescence emission and excitation spectra of the purified pigment indicated that it was actually a flavin peptide. It was, however, different not only from FMN but also from flavin peptides isolated from other sources such as succinate dehydrogenase [EC 1.3.99.1] and monoamine oxidase [EC 1.4.3.4] as regards the pH dependence of fluorescence intensity and the Rf value on thin-layer chromatography. A preliminary analysis showed that the purified flavin compound contained several amino acid residues. Alkaline photolysis of the purified flavin peptide suggested that the isoalloxazine ring of the flavin is involved in its binding to the peptide. The hypsochromic shift of the absorption peak in the near-ultraviolet region suggested further that the linkage between the flavin and the peptide may be mediated by the 8-methyl group of the isoalloxazine nucleus. It can be concluded that the prosthetic group of gulonolactone oxidase is a flavin which is covalently bound to the enzyme protein.

  6. Structure of the Acinetobacter baumannii dithiol oxidase DsbA bound to elongation factor EF-Tu reveals a novel protein interaction site.

    PubMed

    Premkumar, Lakshmanane; Kurth, Fabian; Duprez, Wilko; Grøftehauge, Morten K; King, Gordon J; Halili, Maria A; Heras, Begoña; Martin, Jennifer L

    2014-07-18

    The multidrug resistant bacterium Acinetobacter baumannii is a significant cause of nosocomial infection. Biofilm formation, that requires both disulfide bond forming and chaperone-usher pathways, is a major virulence trait in this bacterium. Our biochemical characterizations show that the periplasmic A. baumannii DsbA (AbDsbA) enzyme has an oxidizing redox potential and dithiol oxidase activity. We found an unexpected non-covalent interaction between AbDsbA and the highly conserved prokaryotic elongation factor, EF-Tu. EF-Tu is a cytoplasmic protein but has been localized extracellularly in many bacterial pathogens. The crystal structure of this complex revealed that the EF-Tu switch I region binds to the non-catalytic surface of AbDsbA. Although the physiological and pathological significance of a DsbA/EF-Tu association is unknown, peptides derived from the EF-Tu switch I region bound to AbDsbA with submicromolar affinity. We also identified a seven-residue DsbB-derived peptide that bound to AbDsbA with low micromolar affinity. Further characterization confirmed that the EF-Tu- and DsbB-derived peptides bind at two distinct sites. These data point to the possibility that the non-catalytic surface of DsbA is a potential substrate or regulatory protein interaction site. The two peptides identified in this work together with the newly characterized interaction site provide a novel starting point for inhibitor design targeting AbDsbA.

  7. Ligand-Bound GeneSwitch Causes Developmental Aberrations in Drosophila that Are Alleviated by the Alternative Oxidase

    PubMed Central

    Andjelković, Ana; Kemppainen, Kia K.; Jacobs, Howard T.

    2016-01-01

    Culture of Drosophila expressing the steroid-dependent GeneSwitch transcriptional activator under the control of the ubiquitous α-tubulin promoter was found to produce extensive pupal lethality, as well as a range of dysmorphic adult phenotypes, in the presence of high concentrations of the inducing drug RU486. Prominent among these was cleft thorax, seen previously in flies bearing mutant alleles of the nuclear receptor Ultraspiracle and many other mutants, as well as notched wings, leg malformations, and bristle abnormalities. Neither the α-tubulin-GeneSwitch driver nor the inducing drug on their own produced any of these effects. A second GeneSwitch driver, under the control of the daughterless promoter, which gave much lower and more tissue-restricted transgene expression, exhibited only mild bristle abnormalities in the presence of high levels of RU486. Coexpression of the alternative oxidase (AOX) from Ciona intestinalis produced a substantial shift in the developmental outcome toward a wild-type phenotype, which was dependent on the AOX expression level. Neither an enzymatically inactivated variant of AOX, nor GFP, or the alternative NADH dehydrogenase Ndi1 from yeast gave any such rescue. Users of the GeneSwitch system should be aware of the potential confounding effects of its application in developmental studies. PMID:27412986

  8. Relevance of the flavin binding to the stability and folding of engineered cholesterol oxidase containing noncovalently bound FAD

    PubMed Central

    Caldinelli, Laura; Iametti, Stefania; Barbiroli, Alberto; Fessas, Dimitrios; Bonomi, Francesco; Piubelli, Luciano; Molla, Gianluca; Pollegioni, Loredano

    2008-01-01

    The flavoprotein cholesterol oxidase (CO) from Brevibacterium sterolicum is a monomeric flavoenzyme containing one molecule of FAD cofactor covalently linked to His69. The elimination of the covalent link following the His69Ala substitution was demonstrated to result in a significant decrease in activity, in the midpoint redox potential of the flavin, and in stability with respect to the wild-type enzyme, but does not modify the overall structure of the enzyme. We used CO as a model system to dissect the changes due to the elimination of the covalent link between the flavin and the protein (by comparing the wild-type and H69A CO holoproteins) with those due to the elimination of the cofactor (by comparing the holo- and apoprotein forms of H69A CO). The apoprotein of H69A CO lacks the characteristic tertiary structure of the holoprotein and displays larger hydrophobic surfaces; its urea-induced unfolding does not occur by a simple two-state mechanism and is largely nonreversible. Minor alterations in the flavin binding region are evident between the native and the refolded proteins, and are likely responsible for the low refolding yield observed. A model for the equilibrium unfolding of H69A CO that also takes into consideration the effects of cofactor binding and dissociation, and thus may be of general significance in terms of the relationships between cofactor uptake and folding in flavoproteins, is presented. PMID:18218720

  9. Inhibition of NADPH oxidase 1 activity and blocking the binding of cytosolic and membrane-bound proteins by honokiol inhibit migratory potential of melanoma cells

    PubMed Central

    Prasad, Ram; Kappes, John C.; Katiyar, Santosh K.

    2016-01-01

    Overexpression of NADPH oxidase 1 (Nox1) in melanoma cells is often associated with increased migration/metastasis rate. To develop effective treatment options, we have examined the effect of honokiol, a phytochemical from Magnolia plant, on the migratory potential of human melanoma cell lines (A375, Hs294t, SK-Mel119 and SK-Mel28) and assessed whether Nox1 is the target. Using an in vitro cell migration assay, we observed that treatment of different melanoma cell lines with honokiol for 24 h resulted in a dose-dependent inhibition of cell migration that was associated with reduction in Nox1 expression and reduced levels of oxidative stress. Treatment of cells with N-acetyl-L-cysteine, an anti-oxidant, also inhibited the migration of melanoma cells. Treatment of cells with diphenyleneiodonium chloride, an inhibitor of Nox1, significantly decreased the migration ability of Hs294t and SK-Mel28 cells. Further, we examined the effect of honokiol on the levels of core proteins (p22phox and p47phox) of the NADPH oxidase complex. Treatment of Hs294t and SK-Mel28 cells with honokiol resulted in accumulation of the cytosolic p47phox protein and decreased levels of the membrane-bound p22phox protein, thus blocking their interaction and inhibiting Nox1 activation. Our in vivo bioluminescence imaging data indicate that oral administration of honokiol inhibited the migration/extravasation and growth of intravenously injected melanoma cells in internal body organs, such as liver, lung and kidney in nude mice, and that this was associated with an inhibitory effect on Nox1 activity in these internal organs/tissues. PMID:26760964

  10. Inhibition of NADPH oxidase 1 activity and blocking the binding of cytosolic and membrane-bound proteins by honokiol inhibit migratory potential of melanoma cells.

    PubMed

    Prasad, Ram; Kappes, John C; Katiyar, Santosh K

    2016-02-16

    Overexpression of NADPH oxidase 1 (Nox1) in melanoma cells is often associated with increased migration/metastasis rate. To develop effective treatment options, we have examined the effect of honokiol, a phytochemical from Magnolia plant, on the migratory potential of human melanoma cell lines (A375, Hs294t, SK-Mel119 and SK-Mel28) and assessed whether Nox1 is the target. Using an in vitro cell migration assay, we observed that treatment of different melanoma cell lines with honokiol for 24 h resulted in a dose-dependent inhibition of cell migration that was associated with reduction in Nox1 expression and reduced levels of oxidative stress. Treatment of cells with N-acetyl-L-cysteine, an anti-oxidant, also inhibited the migration of melanoma cells. Treatment of cells with diphenyleneiodonium chloride, an inhibitor of Nox1, significantly decreased the migration ability of Hs294t and SK-Mel28 cells. Further, we examined the effect of honokiol on the levels of core proteins (p22(phox) and p47(phox)) of the NADPH oxidase complex. Treatment of Hs294t and SK-Mel28 cells with honokiol resulted in accumulation of the cytosolic p47(phox) protein and decreased levels of the membrane-bound p22(phox) protein, thus blocking their interaction and inhibiting Nox1 activation. Our in vivo bioluminescence imaging data indicate that oral administration of honokiol inhibited the migration/extravasation and growth of intravenously injected melanoma cells in internal body organs, such as liver, lung and kidney in nude mice, and that this was associated with an inhibitory effect on Nox1 activity in these internal organs/tissues.

  11. Influence of drugs on albumin and bilirubin interaction.

    PubMed

    Funato, M; Lee, Y; Onishi, S; Cashore, W J

    1989-02-01

    Twenty-eight drugs, including cephem antibiotics and anti-inflammatory agents currently used or considered potentially useful in neonatal intensive care nurseries in Japan, were examined to determine their influence on albumin and bilirubin interaction by means of a glucose oxidase - peroxidase method, using an automated analyzer (Arrows) for unbound bilirubin (U.B.). The apparent binding constant for drugs to the high-affinity site on albumin (KD) was determined. Of cephem antibiotics, latamoxef sodium (LMOX) and cefazolin sodium (CEZ) were found to displace bilirubin from albumin (KD = 5.9 x 10(3) M-1 and 4.5 x 10(3) M-1, respectively) as strongly as Na salicylate (KD = 6.8 x 10(3) M-1). Mephenamate and indomethacin, which are used for medical closure of patent ductus arteriosus in premature infants, were also found to be stronger bilirubin displacers (KD = 1.3 x 10(5) M-1 and 1.2 x 10(5) M-1, respectively) than sulfisoxazole (KD = 1.6 x 10(4) M-1). Maximal displacement factors (MDF's) were also estimated in reference to protein binding (%) and effective serum concentration (M) of each drug in human adults. Of these drugs, mephenamate showed a higher risk of bilirubin displacement (MDF = 3.79) than sulfisoxazole (MDF = 2.58) and LMOX had a higher risk of displacement (MDF = 1.97) than Na salicylate (MDF = 1.85). On the other hand, indomethacin and CEZ showed minimal effects on displacement at therapeutic levels (MDF = 1.03 and 1.00, respectively). At therapeutic serum levels, mephenamate and LMOX may possess the potential for displacing bilirubin from albumin and increasing the risk of bilirubin encephalopathy, in a manner similar to sulfisoxazole.

  12. Structure of the Acinetobacter baumannii Dithiol Oxidase DsbA Bound to Elongation Factor EF-Tu Reveals a Novel Protein Interaction Site

    PubMed Central

    Premkumar, Lakshmanane; Kurth, Fabian; Duprez, Wilko; Grøftehauge, Morten K.; King, Gordon J.; Halili, Maria A.; Heras, Begoña; Martin, Jennifer L.

    2014-01-01

    The multidrug resistant bacterium Acinetobacter baumannii is a significant cause of nosocomial infection. Biofilm formation, that requires both disulfide bond forming and chaperone-usher pathways, is a major virulence trait in this bacterium. Our biochemical characterizations show that the periplasmic A. baumannii DsbA (AbDsbA) enzyme has an oxidizing redox potential and dithiol oxidase activity. We found an unexpected non-covalent interaction between AbDsbA and the highly conserved prokaryotic elongation factor, EF-Tu. EF-Tu is a cytoplasmic protein but has been localized extracellularly in many bacterial pathogens. The crystal structure of this complex revealed that the EF-Tu switch I region binds to the non-catalytic surface of AbDsbA. Although the physiological and pathological significance of a DsbA/EF-Tu association is unknown, peptides derived from the EF-Tu switch I region bound to AbDsbA with submicromolar affinity. We also identified a seven-residue DsbB-derived peptide that bound to AbDsbA with low micromolar affinity. Further characterization confirmed that the EF-Tu- and DsbB-derived peptides bind at two distinct sites. These data point to the possibility that the non-catalytic surface of DsbA is a potential substrate or regulatory protein interaction site. The two peptides identified in this work together with the newly characterized interaction site provide a novel starting point for inhibitor design targeting AbDsbA. PMID:24860094

  13. Genetic Disorders of Bilirubin Metabolism

    DTIC Science & Technology

    Chronic idiopathic jaundice and three other entities that share the features of familial disorders of bilirubin metabolism in the absence of hemolytic disease or obstruction of bile passages are discussed.

  14. The Biological Effects of Bilirubin Photoisomers.

    PubMed

    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.

  15. Effect of bilirubin on triglyceride synthesis in streptozotocin-induced diabetic nephropathy.

    PubMed

    Xu, Jianwei; Lee, Eun Seong; Baek, Seon Ha; Ahn, Shin-Young; Kim, Sejoong; Na, Ki Young; Chae, Dong-Wan; Chin, Ho Jun

    2014-09-01

    We aimed to elucidate the effect of bilirubin on dyslipidemia and nephropathy in a diabetes mellitus (DM) type I animal model. Sprague-Dawley rats were separated into control, DM, and bilirubin-treated DM (Bil) groups. The Bil group was injected intraperitoneally with 60 mg/kg bilirubin 3 times per week and hepatoma cells were cultured with bilirubin at a concentration of 0.3 mg/dL. The Bil group showed lower serum creatinine levels 5 weeks after diabetes onset. Bilirubin treatment also decreased the amount of mesangial matrix, lowered the expression of renal collagen IV and transforming growth factor (TGF)-β1, and reduced the level of apoptosis in the kidney, compared to the DM group. These changes were accompanied by decreased tissue levels of hydrogen superoxide and NADPH oxidase subunit proteins. Bilirubin decreased serum total cholesterol, high-density lipoprotein cholesterol (HDL-C), free fatty acids, and triglycerides (TGs), as well as the TG content in the liver tissues. Bilirubin suppressed protein expression of LXRα, SREBP-1, SCD-1, and FAS, factors involved in TG synthesis that were elevated in the livers of DM rats and hepatoma cells under high-glucose conditions. In conclusion, bilirubin attenuates renal dysfunction and dyslipidemia in diabetes by suppressing LXRα and SREBP-1 expression and oxidative stress.

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

    PubMed

    Hulzebos, Christian V; Dijk, Peter H

    2014-11-01

    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) levels, or bilirubin/albumin (B/A) ratios for that matter, are more closely associated with bilirubin neurotoxicity. In this article, we review bilirubin-albumin binding, UCBfree levels, and B/A ratios in addition to TSB levels to individualize and optimize treatment especially in preterm infants. Methods to measure bilirubin-albumin binding or UCBfree are neither routinely performed in Western clinical laboratories nor incorporated in current management guidelines on unconjugated hyperbilirubinemia. For bilirubin-albumin binding, this seems justified because several of these methods have been challenged, and sufficiently powered prospective trials on the clinical benefits are lacking. Technological advances in the measurement of UCBfree may provide a convenient means for integrating UCBfree measurements into routine clinical management of jaundiced infants. A point-of-care method, as well as determination of UCBfree levels in various newborn populations, is desirable to learn more about variations in time and how various clinical pathophysiological conditions affect UCBfree levels. This will improve the estimation of approximate UCBfree levels associated with neurotoxicity. To delineate the role of UCBfree in the management of jaundiced (preterm) infants, trials are needed using UCBfree as treatment parameter. The additional use of the B/A ratio in jaundiced preterms has been evaluated in the Bilirubin Albumin Ratio Trial (BARTrial; Clinical Trials: ISRCTN74465643) but failed to demonstrate better neurodevelopmental outcome in preterm infants <32 weeks assigned to the study group. Awaiting a study in which infants are assigned to be managed solely on the basis of their B

  17. Bilirubin Binding Capacity in the Preterm Neonate.

    PubMed

    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.

  18. Quantitative imaging of bilirubin by photoacoustic microscopy

    NASA Astrophysics Data System (ADS)

    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.

  19. New insights in bilirubin metabolism and their clinical implications

    PubMed Central

    Sticova, Eva; Jirsa, Milan

    2013-01-01

    Bilirubin, a major end product of heme breakdown, is an important constituent of bile, responsible for its characteristic colour. Over recent decades, our understanding of bilirubin metabolism has expanded along with the processes of elimination of other endogenous and exogenous anionic substrates, mediated by the action of multiple transport systems at the sinusoidal and canalicular membrane of hepatocytes. Several inherited disorders characterised by impaired bilirubin conjugation (Crigler-Najjar syndrome type I and type II, Gilbert syndrome) or transport (Dubin-Johnson and Rotor syndrome) result in various degrees of hyperbilirubinemia of either the predominantly unconjugated or predominantly conjugated type. Moreover, disrupted regulation of hepatobiliary transport systems can explain jaundice in many acquired liver disorders. In this review, we discuss the recent data on liver bilirubin handling based on the discovery of the molecular basis of Rotor syndrome. The data show that a substantial fraction of bilirubin conjugates is primarily secreted by MRP3 at the sinusoidal membrane into the blood, from where they are subsequently reuptaken by sinusoidal membrane-bound organic anion transporting polypeptides OATP1B1 and OATP1B3. OATP1B proteins are also responsible for liver clearance of bilirubin conjugated in splanchnic organs, such as the intestine and kidney, and for a number of endogenous compounds, xenobiotics and drugs. Absence of one or both OATP1B proteins thus may have serious impact on toxicity of commonly used drugs cleared by this system such as statins, sartans, methotrexate or rifampicin. The liver-blood cycling of conjugated bilirubin is impaired in cholestatic and parenchymal liver diseases and this impairment most likely contributes to jaundice accompanying these disorders. PMID:24151358

  20. Photoacoustic microscopy of bilirubin in tissue phantoms

    NASA Astrophysics Data System (ADS)

    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.

  1. The Biological Effects of Bilirubin Photoisomers

    PubMed Central

    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

  2. Redox dependent interactions of the metal sites in carbon monoxide-bound cytochrome c oxidase monitored by infrared and UV/visible spectroelectrochemical methods.

    PubMed

    Dodson, E D; Zhao, X J; Caughey, W S; Elliott, C M

    1996-01-16

    Spectroelectrochemical titration studies involving the binding of the infrared-active probe ligand carbon monoxide (CO) to the heme alpha 3/CuB site of bovine heart cytochrome c oxidase (CcO) have been reexamined. The spectroelectrochemical cell employed was constructed to monitor both the infrared (IR) and visible/Soret spectra of the CcO-CO complex as a function of the overall oxidation state of the enzyme. A number of commonly used electron transfer mediators were employed to shuttle electrons between the redox active sites within the enzyme and the electrode surface. The well-documented shift in the CO infrared stretch band maximum from 1963.3 cm-1 (CcO fully reduced) to 1965.5 cm-1 (CcO partially oxidized) was carefully titrated electrochemically. Deconvolution of the asymmetric CO stretches indicates the existence of two different states of CO vibrators within the enzyme, presumably due to two conformers which are present in a ratio of approximately 5:1. Upon incrementally stepping the potential from the fully reduced state to the partially oxidized state, we found it possible to follow the decrease in the intensity of the original pair of these conformers and the concomitant increase of a resultant pair while maintaining this 5:1 ratio between the conformers. By plotting the change in the deconvoluted CO peak intensities vs the redox potential, as well as the absorbance changes in the visible/Soret spectra vs the redox potential, we found not only that both fit an n = 1 electron process but also that the spectral changes tracked each other identically with experimental error. Furthermore, analysis of the second derivative of the Soret spectra allowed for the qualitative monitoring of the oxidation state of the Fe alpha site which again tracked identically to that of the CO shift in the IR region. These results would seem to confirm earlier suggestions that perturbing the oxidation state of Fe alpha causes a conformational change in the enzyme which affects

  3. Newborn jaundice technologies: unbound bilirubin and bilirubin binding capacity in neonates.

    PubMed

    Amin, Sanjiv B; Lamola, Angelo A

    2011-06-01

    Neonatal jaundice (hyperbilirubinemia), which is 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, no widely available method exists 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.

  4. Bilirubin Binding to PPARα Inhibits Lipid Accumulation.

    PubMed

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

    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.

  5. Bilirubin Binding to PPARα Inhibits Lipid Accumulation

    PubMed Central

    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

  6. The effect of bilirubin photoisomers on unbound-bilirubin concentrations estimated by the peroxidase method.

    PubMed Central

    Itoh, S; Yamakawa, T; Onishi, S; Isobe, K; Manabe, M; Sasaki, K

    1986-01-01

    Unbound bilirubin is oxidized to nearly colourless substances in the presence of H2O2 or ethyl hydroperoxide and horseradish peroxidase. To predict the risk of kernicterus (degenerated yellow pigmentation of nerve cells), this principle has been widely utilized for estimating the concentration of unbound bilirubin in hyperbilirubinaemic serum. However, the serum contains polar geometric photoisomers of bilirubin. Therefore, to clarify the effect of bilirubin photoisomer concentrations on unbound-bilirubin concentration, the concentration of bilirubin and its photoisomer and of unbound bilirubin in samples obtained from experiments in vivo and in vitro were simultaneously and individually estimated by h.p.l.c. and the peroxidase method. During photoirradiation, both in vivo and in vitro, the serum polar (ZE)-bilirubin IX alpha concentration increased remarkably, but unbound-bilirubin values were not affected at all. However, during experiments in vitro, unbound bilirubin concentrations increased only when concentrations of the rather polar (EZ)- and (EE)-cyclobilirubin IX alpha increased considerably in a human serum albumin-bilirubin solution irradiated with blue light. Thus it is concluded that unbound-bilirubin concentrations, and consequently the initial rate of the peroxidase reaction, is not accelerated by the increase in either (ZE)-bilirubin or (EZ)-cyclobilirubin concentration within the clinically observed range. PMID:3545181

  7. Bilirubin and Its Carbohydrate Conjugates

    NASA Astrophysics Data System (ADS)

    Blanckaert, Norbert J. C.

    In mammals, the open tetrapyrrole bilirubin (structure 2, Fig. 1) is the principal degradation product of iron-protoporphyrin-IX (heme). The latter molecule is a tetrapyrrolic macrocycle and plays a critical role in aerobic metabolism by reversibly binding oxygen in hemoglobin and myoglobin, and by serving as the active site in oxidation reactions catalyzed by hemoprotein enzymes. Important cyclic tetrapyrroles in nature related to heme are chlorophylls, which contain magnesium and are derived from protoporphyrin-IX, and vitamin B12, a corrinoid derived from uroporphyrinogen-III.

  8. Formation of photoproducts and cytotoxicity of bilirubin irradiated with turquoise and blue phototherapy light.

    PubMed

    Roll, Ellen Bruzell; Christensen, Terje

    2005-10-01

    To compare a new turquoise ("green") fluorescent phototherapy lamp (490 nm) with a conventional blue phototherapy lamp (450 nm) with respect to cytotoxicity and photochemical effects of bilirubin. Mouse lymphoma cells (L5178Y-R) in the presence of bilirubin solutions were exposed to phototherapy light. Occurrence of necrosis and apoptosis, reduction of mitotic index and inhibited cell growth was assayed by appropriate methods. The presence of bilirubin and its photoisomers was measured by high-pressure liquid chromatography analysis and absorption spectroscopy. At constant and equal light irradiances, the cytotoxic effects in the presence of bilirubin bound to human serum albumin showed that the green lamp caused significantly less necrosis (n = 4, p < 0.05) and less inhibition of cell multiplication (n = 3, p < 0.05) than the blue lamp. A slightly lower apoptotic fraction, although not statistically significant, was observed in cells exposed to the blue lamp. Photo-oxidation of bilirubin was more prominent with blue light irradiation. The photoequilibria between geometric isomers of bilirubin were different for the two lamps; more geometric photoisomers were formed by blue irradiation (n = 6, p < 0.05). The amounts of the most water-soluble isomers (presumably mainly lumirubin) were rather similar for the two lamps. The two lamps were similar in the formation of therapeutically relevant photoproducts, but the blue lamp showed potential in forming more photo-oxidation products and in causing more severe cellular damage in the presence of bilirubin.

  9. Photodamage of the cells in culture sensitized with bilirubin

    NASA Astrophysics Data System (ADS)

    Kozlenkova, O. A.; Plavskaya, L. G.; Mikulich, A. V.; Leusenko, I. A.; Tretyakova, A. I.; Plavskii, V. Yu

    2016-08-01

    It has been shown that exposure to radiation of LED sources of light with an emission band maximum at about 465 and 520 nm having substantially identical damaging effects on animal cells in culture, that are in a logarithmic growth phase and preincubated with pigment. Photobiological effect is caused by photodynamic processes involving singlet oxygen generated by triplet excited sensitizer. Mono-exponential type dependence of cell survival on the energy dose indicates that it is bilirubin that acts as a sensitizer but not its photoproducts. The inclusion of bilirubin in the cells, where it is primarily localized in the mitochondria cells, it is accompanied by multiple amplification photochemical stability compared to pigment molecules bound with albumin

  10. Interaction of bilirubin with human erythrocyte membranes. Bilirubin binding to neuraminidase- and phospholipase-treated membranes.

    PubMed

    Sato, H; Aono, S; Semba, R; Kashiwamata, S

    1987-11-15

    Saturable bilirubin binding to human erythrocyte membranes was measured before and after digestion with neuraminidase and phospholipases. Neuraminidase-treated erythrocyte membranes did not show any change in their binding properties, indicating that gangliosides could be excluded as candidates for saturable bilirubin-binding sites on erythrocyte membranes. Although bilirubin-binding properties of the membranes did not change after phospholipase D digestion, either, phospholipase C treatment greatly enhanced bilirubin binding. Thus it is suggested that a negatively charged phosphoric acid moiety of phospholipids on the membrane surface may play a role to prevent a large amount of bilirubin from binding to the membranes. Further saturable bilirubin binding to inside-out sealed erythrocyte membrane vesicles showed values comparable with those of the right-side-out sealed membranes, suggesting that the bilirubin-binding sites may be distributed on both outer and inner surfaces of the membranes, or may exist in the membranes where bilirubin may be accessible from either side.

  11. Functionalized SBA-15 materials for bilirubin adsorption

    NASA Astrophysics Data System (ADS)

    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.

  12. THE RENAL ELIMINATION OF BILIRUBIN

    PubMed Central

    Haessler, Herbert; Rous, Peyton; Broun, G. O.

    1922-01-01

    The elimination of bile pigment during jaundice is, for practical purposes, unincreased by diuresis from water by mouth. Possibly, though, the flushing of the kidneys tends to lessen pigment accumulation within these organs and thus to diminish a serious potential source of trouble in long continued jaundice. Flood diuresis from intravenous injections of salt solution markedly increases the output of bile pigment. It is important to know the effect of variations in the urinary output on the elimination of bile salts, but methods for the purpose are not available at present. The passage of bile pigment into the kidney cells during jaundice is attested by the presence in the freshly voided urine of desquamated renal elements specifically stained, stippled, or granulated with bilirubin. Pigmentation of this sort is readily to be distinguished from the indiscriminate staining of cellular debris that occurs in icteric urines on standing. It has clinical significance, furnishing direct evidence on the degree of renal change. PMID:19868627

  13. An amperometric bilirubin biosensor based on a conductive poly-terthiophene-Mn(II) complex.

    PubMed

    Rahman, Md Aminur; Lee, Kyung-Sun; Park, Deog-Su; Won, Mi-Sook; Shim, Yoon-Bo

    2008-01-18

    An amperometric bilirubin biosensor was fabricated by complexing the Mn(II) ion with a conducting polymer and the final biosensor surface was coated with a thin polyethyleneimine (PEI) film containing an enzyme, ascorbate oxidase (AsOx). The complexation between poly-5,2'-5',2''-terthiophene-3-carboxylic acid (PolyTTCA) and Mn(II) through the formation of Mn-O bond was confirmed by XPS. The PolyTTCA-Mn(II) complex was also characterized using cyclic voltammetry. The PolyTTCA-Mn(II)/PEI-AsOx biosensor specifically detect bilirubin through the mediated electron transfer by the Mn(II) ion. To optimize the experimental condition, various experimental parameters such as pH, temperature, and applied potential were examined. A linear calibration plot for bilirubin was obtained between 0.1 microM and 50 microM with the detection limit of 40+/-3.8 nM. Interferences from other biological compounds, especially ascorbate and dopamine were efficiently minimized by coating the biosensor surface with PEI-AsOx. The bilirubin sensor exhibited good stability and fast response time (<5s). The applicability of this bilirubin sensor was tested in a human serum sample.

  14. Crystal Structures of Multicopper Oxidase CueO Bound to Copper(I) and Silver(I): Functional Role of a Methonine-Rich Sequence

    SciTech Connect

    Singh, Satish K.; Roberts, Sue A.; McDevitt, Sylvia F.; Weichsel, Andrzej; Wildner, Guenter F.; Grass, Gregor B.; Rensing, Christopher; Montfort, William R.

    2011-10-24

    The multicopper oxidase CueO oxidizes toxic Cu(I) and is required for copper homeostasis in Escherichia coli. Like many proteins involved in copper homeostasis, CueO has a methionine-rich segment that is thought to be critical for copper handling. How such segments function is poorly understood. Here, we report the crystal structure of CueO at 1.1 {angstrom} with the 45-residue methionine-rich segment fully resolved, revealing an N-terminal helical segment with methionine residues juxtaposed for Cu(I) ligation and a C-terminal highly mobile segment rich in methionine and histidine residues. We also report structures of CueO with a C500S mutation, which leads to loss of the T1 copper, and CueO with six methionines changed to serine. Soaking C500S CueO crystals with Cu(I), or wild-type CueO crystals with Ag(I), leads to occupancy of three sites, the previously identified substrate-binding site and two new sites along the methionine-rich helix, involving methionines 358, 362, 368, and 376. Mutation of these residues leads to a {approx}4-fold reduction in kcat for Cu(I) oxidation. Ag(I), which often appears with copper in nature, strongly inhibits CueO oxidase activities in vitro and compromises copper tolerance in vivo, particularly in the absence of the complementary copper efflux cus system. Together, these studies demonstrate a role for the methionine-rich insert of CueO in the binding and oxidation of Cu(I) and highlight the interplay among cue and cus systems in copper and silver homeostasis.

  15. Crystal structures of multicopper oxidase CueO bound to copper(I) and silver(I): functional role of a methionine-rich sequence.

    PubMed

    Singh, Satish K; Roberts, Sue A; McDevitt, Sylvia F; Weichsel, Andrzej; Wildner, Guenter F; Grass, Gregor B; Rensing, Christopher; Montfort, William R

    2011-10-28

    The multicopper oxidase CueO oxidizes toxic Cu(I) and is required for copper homeostasis in Escherichia coli. Like many proteins involved in copper homeostasis, CueO has a methionine-rich segment that is thought to be critical for copper handling. How such segments function is poorly understood. Here, we report the crystal structure of CueO at 1.1 Å with the 45-residue methionine-rich segment fully resolved, revealing an N-terminal helical segment with methionine residues juxtaposed for Cu(I) ligation and a C-terminal highly mobile segment rich in methionine and histidine residues. We also report structures of CueO with a C500S mutation, which leads to loss of the T1 copper, and CueO with six methionines changed to serine. Soaking C500S CueO crystals with Cu(I), or wild-type CueO crystals with Ag(I), leads to occupancy of three sites, the previously identified substrate-binding site and two new sites along the methionine-rich helix, involving methionines 358, 362, 368, and 376. Mutation of these residues leads to a ∼4-fold reduction in k(cat) for Cu(I) oxidation. Ag(I), which often appears with copper in nature, strongly inhibits CueO oxidase activities in vitro and compromises copper tolerance in vivo, particularly in the absence of the complementary copper efflux cus system. Together, these studies demonstrate a role for the methionine-rich insert of CueO in the binding and oxidation of Cu(I) and highlight the interplay among cue and cus systems in copper and silver homeostasis.

  16. Bilirubin activates transcription of HIF-1α in human proximal tubular cells cultured in the physiologic oxygen content.

    PubMed

    Kim, Sung Gyun; Ahn, Shin-Young; Lee, Eun Seong; Kim, Sejoong; Na, Ki Young; Chae, Dong-Wan; Chin, Ho Jun

    2014-09-01

    The expression of hypoxia-inducible factor (HIF) is influenced by reactive oxygen species (ROS). Effect of bilirubin on HIF-1 expression in proximal tubular cells was investigated under physiological oxygen concentration, which is relative hypoxic condition mimicking oxygen content in the medulla of renal tissue. The human kidney (HK2) cells were cultured in 5% oxygen with or without bilirubin. HIF-1α protein expression was increased by bilirubin treatment at 0.01-0.2 mg/dL concentration. The messenger RNA expression of HIF-1α was increased by 1.69±0.05 folds in the cells cultured with 0.1 mg/dL bilirubin, compared to the control cells. The inhibitors of PI3K/mTOR, PI3K/AKT, and ERK 1/2 pathways did not attenuate increased HIF-1α expression by bilirubin. HIF-1α expression decreased by 10 µM exogenous hydrogen peroxide (H2O2); scavenger of ROS with or without bilirubin in the HK2 cells increased HIF-1α concentration more than that in the cells without bilirubin. Exogenous H2O2 decreased the phosphorylation of P70S6 kinase, which was completely reversed by bilirubin treatment. Knockdown of NOX4 gene by small interfering RNA (siRNA) increased HIF-1α mRNA expression. In coonclusion, bilirubin enhances HIF-1α transcription as well as the up-regulation of HIF-1α protein translation through the attenuation of ROS and subunits of NADPH oxidase.

  17. Halides inhibition of multicopper oxidases studied by FTIR spectroelectrochemistry using azide as an active infrared probe.

    PubMed

    Di Bari, Chiara; Mano, Nicolas; Shleev, Sergey; Pita, Marcos; L De Lacey, Antonio

    2017-10-03

    An infrared spectroelectrochemical study of Trametes hirsuta laccase and Magnaporthe oryzae bilirubin oxidase has been performed using azide, an inhibitor of multicopper oxidases, as an active infrared probe incorporated into the T2/T3 copper cluster of the enzymes. The redox potential-controlled measurements indicate that N3(-) stretching IR bands of azide ion bound to the T2/T3 cluster are only detected for the oxidized enzymes, confirming that azide only binds to Cu(2+). Moreover, the process of binding/dissociation of azide ion is shown to be reversible. The interaction of halide anions, which also inhibit multicopper oxidases, with the active site of the enzymes was studied by measuring the changes in the azide FTIR bands. Enzymes inhibited by azide respond differently upon addition of fluoride or chloride ions to the sample solution inhibited by azide. Fluoride ions compete with azide for binding at one of the T2/T3 Cu ions, whereas competition from chloride ions is much less evident.

  18. Animal pigment bilirubin discovered in plants.

    PubMed

    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.

  19. Morphological development and cytochrome c oxidase activity in Streptomyces lividans are dependent on the action of a copper bound Sco protein

    PubMed Central

    Blundell, Katie L. I. M.; Wilson, Michael T.; Svistunenko, Dimitri A.; Vijgenboom, Erik; Worrall, Jonathan A. R.

    2013-01-01

    Copper has an important role in the life cycle of many streptomycetes, stimulating the developmental switch between vegetative mycelium and aerial hyphae concomitant with the production of antibiotics. In streptomycetes, a gene encoding for a putative Sco-like protein has been identified and is part of an operon that contains two other genes predicted to handle cellular copper. We report on the Sco-like protein from Streptomyces lividans (ScoSl) and present a series of experiments that firmly establish a role for ScoSl as a copper metallochaperone as opposed to a role as a thiol-disulphide reductase that has been assigned to other bacterial Sco proteins. Under low copper concentrations, a Δsco mutant in S. lividans displays two phenotypes; the development switch between vegetative mycelium and aerial hyphae stalls and cytochrome c oxidase (CcO) activity is significantly decreased. At elevated copper levels, the development and CcO activity in the Δsco mutant are restored to wild-type levels and are thus independent of ScoSl. A CcO knockout reveals that morphological development is independent of CcO activity leading us to suggest that ScoSl has at least two targets in S. lividans. We establish that one ScoSl target is the dinuclear CuA domain of CcO and it is the cupric form of ScoSl that is functionally active. The mechanism of cupric ion capture by ScoSl has been investigated, and an important role for a conserved His residue is identified. PMID:23345541

  20. Morphological development and cytochrome c oxidase activity in Streptomyces lividans are dependent on the action of a copper bound Sco protein.

    PubMed

    Blundell, Katie L I M; Wilson, Michael T; Svistunenko, Dimitri A; Vijgenboom, Erik; Worrall, Jonathan A R

    2013-01-23

    Copper has an important role in the life cycle of many streptomycetes, stimulating the developmental switch between vegetative mycelium and aerial hyphae concomitant with the production of antibiotics. In streptomycetes, a gene encoding for a putative Sco-like protein has been identified and is part of an operon that contains two other genes predicted to handle cellular copper. We report on the Sco-like protein from Streptomyces lividans (Sco(Sl)) and present a series of experiments that firmly establish a role for Sco(Sl) as a copper metallochaperone as opposed to a role as a thiol-disulphide reductase that has been assigned to other bacterial Sco proteins. Under low copper concentrations, a Δsco mutant in S. lividans displays two phenotypes; the development switch between vegetative mycelium and aerial hyphae stalls and cytochrome c oxidase (CcO) activity is significantly decreased. At elevated copper levels, the development and CcO activity in the Δsco mutant are restored to wild-type levels and are thus independent of Sco(Sl). A CcO knockout reveals that morphological development is independent of CcO activity leading us to suggest that Sco(Sl) has at least two targets in S. lividans. We establish that one Sco(Sl) target is the dinuclear Cu(A) domain of CcO and it is the cupric form of Sco(Sl) that is functionally active. The mechanism of cupric ion capture by Sco(Sl) has been investigated, and an important role for a conserved His residue is identified.

  1. Crystal Structure of the Dithiol Oxidase DsbA Enzyme from Proteus Mirabilis Bound Non-covalently to an Active Site Peptide Ligand

    PubMed Central

    Kurth, Fabian; Duprez, Wilko; Premkumar, Lakshmanane; Schembri, Mark A.; Fairlie, David P.; Martin, Jennifer L.

    2014-01-01

    The disulfide bond forming DsbA enzymes and their DsbB interaction partners are attractive targets for development of antivirulence drugs because both are essential for virulence factor assembly in Gram-negative pathogens. Here we characterize PmDsbA from Proteus mirabilis, a bacterial pathogen increasingly associated with multidrug resistance. PmDsbA exhibits the characteristic properties of a DsbA, including an oxidizing potential, destabilizing disulfide, acidic active site cysteine, and dithiol oxidase catalytic activity. We evaluated a peptide, PWATCDS, derived from the partner protein DsbB and showed by thermal shift and isothermal titration calorimetry that it binds to PmDsbA. The crystal structures of PmDsbA, and the active site variant PmDsbAC30S were determined to high resolution. Analysis of these structures allows categorization of PmDsbA into the DsbA class exemplified by the archetypal Escherichia coli DsbA enzyme. We also present a crystal structure of PmDsbAC30S in complex with the peptide PWATCDS. The structure shows that the peptide binds non-covalently to the active site CXXC motif, the cis-Pro loop, and the hydrophobic groove adjacent to the active site of the enzyme. This high-resolution structural data provides a critical advance for future structure-based design of non-covalent peptidomimetic inhibitors. Such inhibitors would represent an entirely new antibacterial class that work by switching off the DSB virulence assembly machinery. PMID:24831013

  2. Does bilirubin protect against developing diabetes mellitus?

    PubMed

    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.

  3. Intermolecular interactions in the bilirubin-cholate-silica system

    NASA Astrophysics Data System (ADS)

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

    2007-06-01

    Bilirubin-cholate interactions in aqueous solutions were studied. The constants of binding of bilirubin with taurocholate dimers and taurodeoxycholate trimers were calculated. The adsorption of bilirubin and cholates on the surface of highly dispersed silica was studied. It was shown that taurine-conjugated cholates are poorly adsorbed from micellar solutions on the silica surface, the specific amount of bilirubin adsorbed decreases with increasing concentration of cholates in the solution, the affinity of free bilirubin for the silica surface is independent of the nature of the cholic acid, and that the affinity of cholate-bilirubin complexes for the silica surface is lower than the affinity of free bilirubin.

  4. Relation between the catalytic efficiency of the synthetic analogues of catechol oxidase with their electrochemical property in the free state and substrate-bound state.

    PubMed

    Chakraborty, Prateeti; Adhikary, Jaydeep; Ghosh, Bipinbihari; Sanyal, Ria; Chattopadhyay, Shyamal Kumar; Bauzá, Antonio; Frontera, Antonio; Zangrando, Ennio; Das, Debasis

    2014-08-18

    A library of 15 dicopper complexes as synthetic analogues of catechol oxidase has been synthesized with the aim to determine the relationship between the electrochemical behavior of the dicopper(II) species in the absence as well as in the presence of 3,5-di-tert-butylcatechol (3,5-DTBC) as model substrate and the catalytic activity, kcat, in DMSO medium. The complexes have been characterized by routine physicochemical techniques as well as by X-ray single-crystal structure analysis in some cases. Fifteen "end-off" compartmental ligands have been designed as 1 + 2 Schiff-base condensation product of 2,6-diformyl-4-R-phenol (R = Me, (t)Bu, and Cl) and five different amines, N-(2-aminoethyl)piperazine, N-(2-aminoethyl)pyrrolidine, N-(2-aminoethyl)morpholine, N-(3-aminopropyl)morpholine, and N-(2-aminoethyl)piperidine. Interestingly, in case of the combination of 2,6-diformyl-4-methylphenol and N-(2-aminoethyl)morpholine/N-(3-aminopropyl)morpholine/N-(2-aminoethyl)piperidine 1 + 1 condensation becomes the reality and the ligands are denoted as L2(1-3). On reaction of copper(II) nitrate with L2(1-3) in situ complexes 3, 12, and 13 are formed having general formula Cu2(L2(1-3))2(NO3)2. The remaining 12 ligands obtained as 1 + 2 condensation products are denoted as L1(1-12), which produce complexes having general formula Cu2(L1(1-12))(NO3)2. Catecholase activity of all 15 complexes has been investigated in DMSO medium using 3,5-DTBC as model substrate. Treatment on the basis of Michaelis-Menten model has been applied for kinetic study, and thereby turnover number, kcat, values have been evaluated. Cyclic voltametric (CV) and differential pulse voltametric (DPV) studies of the complexes in the presence as well as in the absence of 3,5-DTBC have been thoroughly investigated in DMSO medium. From those studies it is evident that oxidation of 3,5-DTBC catalyzed by dicopper(II) complexes proceed via two steps: first, semibenzoquinone followed by benzoquinone with concomitant

  5. The nonerythropoietic component of early bilirubin

    PubMed Central

    Levitt, M.; Schacter, B. A.; Zipursky, A.; Israels, L. G.

    1968-01-01

    The early labeled bilirubin consists of two primary components. The more rapidly synthesized of the two is independent of erythropoiesis (nonerythropoietic), whereas the second fraction is related to red cell production (erythyropoietic). The present studies concern the origin of the nonerythropoietic component. The nonerythropoietic, early labeled bilirubin was studied in bile fistula rats with (delta ALA)-4-14C delta aminolevulinic acid and glycine-2-14C as precursors. That nephrectomy did not reduce the size of this component despite the large and rapidly turning over pool of renal heme suggests that this pool may be of minor importance in its production. Intoxication with lead to a level that reduced hepatic heme synthesis was associated with a decrease in early bilirubin formation. The synthesis of this bilirubin was assessed in animals with phenobarbital-induced heme protein and cycloheximide-suppressed protein synthesis. Rats pretreated with phenobarbital at a dose level of 60 mg/kg with induction of cytochrome P-450 synthesis showed a minor increase in early labeling when glycine-2-14C but not when delta ALA-4-14C was used as precursor. Rats given cycloheximide at a dose level that markedly reduced hepatic protein and cytochrome P-450 synthesis but allowed heme synthesis to continue at 60% of its pretreatment level synthesized normal or increased amounts of early bilirubin from delta ALA-4-14C. Allylisopropylacetamide intoxication caused little change in early bilirubin formation, whereas aminotriazole given at a time after maximal hepatic heme labeling produced a small but significant increase in the appearance of labeled bilirubin. These findings indicate that early bilirubin production is little influenced by increased hepatic porphyrin synthesis or by changes in the rapidly turning over heme protein P-450. A minimal increase attends catalase inactivation by aminotriazole. Normal or increased synthesis takes place in the presence of suppression of

  6. Supramolecular Complexes Formed in Systems Bile Salt-Bilirubin-Silica

    NASA Astrophysics Data System (ADS)

    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.

  7. PPARα: A Master Regulator of Bilirubin Homeostasis

    PubMed Central

    Kaeding, Jenny; El Husseini, Diala; Rudkowska, Iwona; Verreault, Mélanie

    2014-01-01

    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. PMID:25147562

  8. PPARα: A Master Regulator of Bilirubin Homeostasis.

    PubMed

    Bigo, Cyril; Kaeding, Jenny; El Husseini, Diala; Rudkowska, Iwona; Verreault, Mélanie; Vohl, Marie Claude; Barbier, Olivier

    2014-01-01

    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.

  9. Application of phenol red as a marker ligand for bilirubin binding site at subdomain IIA on human serum albumin.

    PubMed

    Sochacka, Jolanta

    2015-10-01

    The drug-bilirubin interaction for all drugs administered especially to infants with hyperbilirubinemia should be evaluated for their ability to displace bilirubin and vice versa. In order to examine whether phenol red (PhRed) can be used as a marker for bilirubin binding site located in subdomain IIA the interaction between PhRed and human serum albumin (HSA) in buffer solution or in normal and pathological sera solutions with different HSA:bilirubin molar ratio was investigated using absorption/absorption difference spectroscopy and molecular docking method. Six sulfonamides representing the binding site in the subdomain IIA and known to influence the binding of bilirubin were used for the PhRed displacement studies. The absorption spectra for PhRed completely bound to HSA showed significant differences in the spectral characteristic relative to the spectral profile of free PhRed. The intensity of the peak originating from the bivalent anionic form of dye was strongly reduced and the maximum peak position was red-shifted by 12 nm. The binding constant (K) of the bivalent anionic form of PhRed, calculated from absorbance data, was 1.61 · 10(4) L mol(-1). The variations of the absorption and absorption difference spectra of PhRed in the presence of HSA-bilirubin complex were indicative of the inhibition of PhRed binding process by bilirubin. Binding of PhRed carried out in the presence of sulfonamides showed that drugs and PhRed have a common site which also involves bilirubin. In agreement with the results of the spectroscopic analysis and molecular docking it was concluded that PhRed may be applied as a marker in the study of the binding of drugs to high-affinity bilirubin binding site.

  10. EKTACHEM bilirubin fraction Bc as a predictor of liver transplant rejection.

    PubMed

    Cox, C J; Valdiserri, R O; Zerbe, T R; Genter, J L

    1987-10-01

    Bilirubin fractions Bc and DELTA, not routinely available prior to the EKTACHEM Chemistry Analyzer and its slide methodology, were studied in an outpatient population of liver transplant recipients. A preliminary evaluation by the authors has shown that direct bilirubin (DBILI) levels in the normal range consist almost exclusively of DELTA (protein-bound conjugated bilirubin), while at elevated DBILI levels, an increasing amount of Bc (non-protein-bound conjugated bilirubin) is measured as well. The present study evaluated the clinical significance of Bc in the serum of 80 liver transplant recipients as a means of identifying episodes of rejection. Each patient was classified into rejection or nonrejection categories based on clinical status, liver biopsy results, and/or response to therapy. Eighteen patients were classified as experiencing an episode of rejection during the period of this study. Fourteen of these (77.8%) had Bc levels that ranged from 0.1 to 6.8 mg/dl. Sixty two patients were classified in the nonrejection category. Fourteen (22.6%) of these patients had Bc levels that ranged from 0.1 to 0.6 mg/dl. In our outpatient liver transplant recipients with Bc greater than or equal to 0.1 mg/dl, the relative risk of rejection (% of rejection patients with Bc/% of nonrejection patients with Bc) was 3.44. This value indicates that Bc determination may be a helpful adjunct in the assessment of rejection.

  11. Can Excess Bilirubin Levels Cause Learning Difficulties?

    ERIC Educational Resources Information Center

    Pretorius, E.; Naude, H.; Becker, P. J.

    2002-01-01

    Examined learning problems in South African sample of 7- to 14-year-olds whose mothers reported excessively high infant bilirubin shortly after the child's birth. Found that this sample had lowered verbal ability with the majority also showing impaired short-term and long-term memory. Findings suggested that impaired formation of astrocytes…

  12. Can Excess Bilirubin Levels Cause Learning Difficulties?

    ERIC Educational Resources Information Center

    Pretorius, E.; Naude, H.; Becker, P. J.

    2002-01-01

    Examined learning problems in South African sample of 7- to 14-year-olds whose mothers reported excessively high infant bilirubin shortly after the child's birth. Found that this sample had lowered verbal ability with the majority also showing impaired short-term and long-term memory. Findings suggested that impaired formation of astrocytes…

  13. Analysis of wavelength-dependent photoisomerization quantum yields in bilirubins by fitting two exciton absorption bands

    NASA Astrophysics Data System (ADS)

    Mazzoni, M.; Agati, G.; Troup, G. J.; Pratesi, R.

    2003-09-01

    The absorption spectra of bilirubins were deconvoluted by two Gaussian curves of equal width representing the exciton bands of the non-degenerate molecular system. The two bands were used to study the wavelength dependence of the (4Z, 15Z) rightarrow (4Z, 15E) configurational photoisomerization quantum yield of the bichromophoric bilirubin-IXalpha (BR-IX), the intrinsically asymmetric bile pigment associated with jaundice and the symmetrically substituted bilirubins (bilirubin-IIIalpha and mesobilirubin-XIIIalpha), when they are irradiated in aqueous solution bound to human serum albumin (HSA). The same study was performed for BR-IX in ammoniacal methanol solution (NH4OH/MeOH). The quantum yields of the configurational photoprocesses were fitted with a combination function of the two Gaussian bands normalized to the total absorption, using the proportionality coefficients and a scaling factor as parameters. The decrease of the (4Z, 15Z) rightarrow (4Z, 15E) quantum yield with increasing wavelength, which occurs for wavelengths longer than the most probable Franck-Condon transition of the molecule, did not result in a unique function of the exciton absorptions. In particular we found two ranges corresponding to different exciton interactions with different proportionality coefficients and scaling factors. The wavelength-dependent photoisomerization of bilirubins was described as an abrupt change in quantum yield as soon as the resulting excitation was strongly localized in each chromophore. The change was correlated to a variation of the interaction between the two chromophores when the short-wavelength exciton absorption became vanishingly small. With the help of the circular dichroism (CD) spectrum of BR-IX in HSA, a small band was resolved in the bilirubin absorption spectrum, delivering part of the energy required for the (4Z, 15Z) rightarrow (4Z, 15E) photoisomerization of the molecule.

  14. Bilirubin is an Endogenous Antioxidant in Human Vascular Endothelial Cells

    PubMed Central

    Ziberna, Lovro; Martelanc, Mitja; Franko, Mladen; Passamonti, Sabina

    2016-01-01

    Bilirubin is a standard serum biomarker of liver function. Inexplicably, it is inversely correlated with cardiovascular disease risk. Given the role of endothelial dysfunction in originating cardiovascular diseases, direct analysis of bilirubin in the vascular endothelium would shed light on these relationships. Hence, we used high-performance liquid chromatography coupled with thermal lens spectrometric detection and diode array detection for the determination of endogenous cellular IXα-bilirubin. To confirm the isomer IXα-bilirubin, we used ultra-performance liquid chromatography coupled with a high-resolution mass spectrometer using an electrospray ionization source, as well as tandem mass spectrometric detection. We measured bilirubin in both arterial and venous rat endothelium (0.9–1.5 pmol mg−1 protein). In the human endothelial Ea.hy926 cell line, we demonstrated that intracellular bilirubin (3–5 pmol mg−1 protein) could be modulated by either extracellular bilirubin uptake, or by up-regulation of heme oxygenase-1, a cellular enzyme related to endogenous bilirubin synthesis. Moreover, we determined intracellular antioxidant activity by bilirubin, with EC50 = 11.4 ± 0.2 nM, in the range of reported values of free serum bilirubin (8.5–13.1 nM). Biliverdin showed similar antioxidant properties as bilirubin. We infer from these observations that intra-endothelial bilirubin oscillates, and may thus be a dynamic factor of the endothelial function. PMID:27381978

  15. Detection of bilirubin conjugates in faeces of germfree rats.

    PubMed

    Saxerholt, H; Midtvedt, T; Gustafsson, B E

    1983-10-01

    The presence of bilirubin conjugates in faeces from germfree (GF) and conventional (CONV) rats was tested after using affinity chromatography and Porapak Q chromatography as clean-up procedures. The bilirubin conjugates were detected as their ethyl anthranilate azopigments after separation by thin layer chromatography (tlc). Azopigments prepared from bile of GF and CONV rats served as a reference material for the tlc analysis. After tlc of the faecal azopigment preparations it was concluded that GF rat faeces contains bilirubin conjugates, while faeces from CONV rats is devoid of conjugated bilirubin. The findings suggest that the main bilirubin conjugates present in faeces from GF rats are of the glucuronic acid type.

  16. Bilirubin in coronary artery disease: Cytotoxic or protective?

    PubMed Central

    Gupta, Nancy; Singh, Tavankit; Chaudhary, Rahul; Garg, Sushil K; Sandhu, Gurprataap Singh; Mittal, Varun; Gupta, Rahul; Bodin, Roxana; Sule, Sachin

    2016-01-01

    Bilirubin has traditionally been considered a cytotoxic waste product. However, recent studies have shown bilirubin to have anti-oxidant, anti-inflammatory, vasodilatory, anti-apoptotic and anti-proliferative functions. These properties potentially confer bilirubin a new role of protection especially in coronary artery disease (CAD), which is a low grade inflammatory process exacerbated by oxidative stress. In fact, recent literature reports an inverse relationship between serum concentration of bilirubin and the presence of CAD. In this article, we review the current literature exploring the association between levels of bilirubin and risk of CAD. We conclude that current evidence is inconclusive regarding the protective effect of bilirubin on CAD. A causal relationship between low serum bilirubin level and increased risk of CAD is not currently established. PMID:27867680

  17. Functionalized Magnetic Fe3O4-β-Cyclodextran Nanoparticles for Efficient Removal of Bilirubin.

    PubMed

    Han, Lulu; Chu, Simin; Wei, Houliang; Ren, Jun; Xu, Li; Jia, Lingyun

    2016-06-01

    Bilirubin (BR), as a lipophilic toxin, can binds and deposits in various tissues, especially the brain tissue, leading to hepatic coma and even death. Magnetic nanoparticles adsorbent modified by β-cyclodextran (Fe3O4-β-CD) was developed to remove the BR from the plasma. Fe3O4-β-CD nanoparticles was prepared through Schiff base reaction between the polyethylenimine (PEI)-modified Fe3O4 and aldehyde-functionalized β-CD, and characterized by Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and dynamic light scattering (DLS). Under optimized conditions, the Fe3O4-β-CD adsorbent could adsorb 225.6 mg/g free BR in PBS and reach the adsorption equilibrium within 90 min mainly through hydrophobic interaction; Moreover, the adsorbent displayed better adsorption capability in a dialysis system for BSA-bound bilirubin, plasma bilirubin and total bile acid, and the removal rates of those were 66%, 31% and 41% respectively. Because of the advantages of fast separation and purification process, low preparation cost, good adsorption capability for plasma bilirubin, Fe3O4-β-CD may become an economical and promising absorbent of BR for clinical applications.

  18. Kinetics of oxidation of bilirubin and its protein complex by hydrogen peroxide in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Solomonov, A. V.; Rumyantsev, E. V.; Antina, E. V.

    2010-12-01

    A comparative study of oxidation reactions of bilirubin and its complex with albumin was carried out in aqueous solutions under the action of hydrogen peroxide and molecular oxygen at different pH values. Free radical oxidation of the pigment in both free and bound forms at pH 7.4 was shown not to lead to the formation of biliverdin, but to be associated with the decomposition of the tetrapyrrole chromophore into monopyrrolic products. The effective and true rate constants of the reactions under study were determined. It was assumed that one possible mechanism of the oxidation reaction is associated with the interaction of peroxyl radicals and protons of the NH groups of bilirubin molecules at the limiting stage with the formation of a highly reactive radical intermediate. The binding of bilirubin with albumin was found to result in a considerable reduction in the rate of the oxidation reaction associated with the kinetic manifestation of the protein protection effect. It was found that the autoxidation of bilirubin by molecular oxygen with the formation of biliverdin at the intermediate stage can be observed with an increase in the pH of solutions.

  19. Limitations and opportunities of transcutaneous bilirubin measurements.

    PubMed

    Bosschaart, Nienke; Kok, Joke H; Newsum, Astrid M; Ouweneel, Dagmar M; Mentink, Rosaline; van Leeuwen, Ton G; Aalders, Maurice C G

    2012-04-01

    Although transcutaneous bilirubinometers have existed for over 30 years, the clinical utility of the technique is limited to a screening method for hyperbilirubinemia, rather than a replacement for invasive blood sampling. In this study, we investigate the reason for this limited clinical value and address possibilities for improvement. To obtain better insight into the physiology of bilirubin measurements, we evaluated a transcutaneous bilirubinometer that determines not only the cutaneous bilirubin concentration (TcB) but also the blood volume fraction (BVF) in the investigated skin volume. For 49 neonates (gestational age 30 ± 3.1 weeks, postnatal age 6 [4-10] days) at our NICU, we performed 124 TcB and 55 BVF measurements. The TcB correlated well with the total serum bilirubin concentration (TSB) (r = 0.88) with an uncertainty of 55 µmol/L. The BVF in the measured skin volume ranged between 0.1% and 0.75%. The performance of our bilirubinometer is comparable to existing transcutaneous devices. The limited clinical value of current bilirubinometers can be explained by the low BVF in the skin volume that is probed by these devices. Because the TcB depends for over 99% on the contribution of extravascular bilirubin, it is a physiologically different parameter from the TSB. Hence, the standard method of evaluation that compares the TcB to the TSB is insufficient to fully investigate the clinical value of transcutaneous bilirubinometers, ie, their predictive value for kernicterus. We suggest that the clinical value may be improved considerably by changing either the method of evaluation or the technological design of transcutaneous bilirubinometers.

  20. A Thermostable Bilirubin-Oxidizing Enzyme from Activated Sludge Isolated by a Metagenomic Approach

    PubMed Central

    Kimura, Nobutada; Kamagata, Yoichi

    2016-01-01

    A gene coding for a multicopper oxidase (BopA) was identified through the screening of a metagenomic library constructed from wastewater treatment activated sludge. The recombinant BopA protein produced in Escherichia coli exhibited oxidation activity toward 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) in the presence of copper, suggesting that BopA is laccase. A bioinformatic analysis of the bopA gene sequence indicated that it has a phylogenetically bacterial origin, possibly derived from a bacterium within the phylum Deinococcus-Thermus. Purified BopA exhibited maximum activity at pH 7.5 with bilirubin as its substrate and was found to be active over a markedly broad pH range from 6 to 11. It also showed notable thermostability; its activity remained intact even after a heat treatment at 90°C for 60 min. This enzyme is a thermostable-bilirubin oxidase that exhibits markedly higher thermostability than that previously reported for laccases. PMID:27885197

  1. A Thermostable Bilirubin-Oxidizing Enzyme from Activated Sludge Isolated by a Metagenomic Approach.

    PubMed

    Kimura, Nobutada; Kamagata, Yoichi

    2016-12-23

    A gene coding for a multicopper oxidase (BopA) was identified through the screening of a metagenomic library constructed from wastewater treatment activated sludge. The recombinant BopA protein produced in Escherichia coli exhibited oxidation activity toward 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) in the presence of copper, suggesting that BopA is laccase. A bioinformatic analysis of the bopA gene sequence indicated that it has a phylogenetically bacterial origin, possibly derived from a bacterium within the phylum Deinococcus-Thermus. Purified BopA exhibited maximum activity at pH 7.5 with bilirubin as its substrate and was found to be active over a markedly broad pH range from 6 to 11. It also showed notable thermostability; its activity remained intact even after a heat treatment at 90°C for 60 min. This enzyme is a thermostable-bilirubin oxidase that exhibits markedly higher thermostability than that previously reported for laccases.

  2. High Electrocatalytic Activity of Tethered Multicopper Oxidase-Carbon Nanotube Conjugates (POSTPRINT)

    DTIC Science & Technology

    2010-12-01

    nanotubes, laccase , pyrenebutanoic acid-succinimidyl ester, moleculat tether, biofuel cell, multicopper oxidase U U U UU 6 Glenn R. Johnson Reset...two MCO were selected as model redox enzymes, laccase from Trametes versicolor and bilirubin oxidase (BOx) from Myrothecium verrucaria. The enzymes...immobilization efficiency was examined first using standard biochemical assays.w The assay showed that B20 U of laccase was associated with the electrode

  3. Structural Insights into Sulfite Oxidase Deficiency

    SciTech Connect

    Karakas,E.; Wilson, H.; Graf, T.; Xiang, S.; Jaramillo-Busquets, S.; Rajagopalan, K.; Kisker, C.

    2005-01-01

    Sulfite oxidase deficiency is a lethal genetic disease that results from defects either in the genes encoding proteins involved in molybdenum cofactor biosynthesis or in the sulfite oxidase gene itself. Several point mutations in the sulfite oxidase gene have been identified from patients suffering from this disease worldwide. Although detailed biochemical analyses have been carried out on these mutations, no structural data could be obtained because of problems in crystallizing recombinant human and rat sulfite oxidases and the failure to clone the chicken sulfite oxidase gene. We synthesized the gene for chicken sulfite oxidase de novo, working backward from the amino acid sequence of the native chicken liver enzyme by PCR amplification of a series of 72 overlapping primers. The recombinant protein displayed the characteristic absorption spectrum of sulfite oxidase and exhibited steady state and rapid kinetic parameters comparable with those of the tissue-derived enzyme. We solved the crystal structures of the wild type and the sulfite oxidase deficiency-causing R138Q (R160Q in humans) variant of recombinant chicken sulfite oxidase in the resting and sulfate-bound forms. Significant alterations in the substrate-binding pocket were detected in the structure of the mutant, and a comparison between the wild type and mutant protein revealed that the active site residue Arg-450 adopts different conformations in the presence and absence of bound sulfate. The size of the binding pocket is thereby considerably reduced, and its position relative to the cofactor is shifted, causing an increase in the distance of the sulfur atom of the bound sulfate to the molybdenum.

  4. Structural insights into sulfite oxidase deficiency.

    PubMed

    Karakas, Erkan; Wilson, Heather L; Graf, Tyler N; Xiang, Song; Jaramillo-Busquets, Sandra; Rajagopalan, K V; Kisker, Caroline

    2005-09-30

    Sulfite oxidase deficiency is a lethal genetic disease that results from defects either in the genes encoding proteins involved in molybdenum cofactor biosynthesis or in the sulfite oxidase gene itself. Several point mutations in the sulfite oxidase gene have been identified from patients suffering from this disease worldwide. Although detailed biochemical analyses have been carried out on these mutations, no structural data could be obtained because of problems in crystallizing recombinant human and rat sulfite oxidases and the failure to clone the chicken sulfite oxidase gene. We synthesized the gene for chicken sulfite oxidase de novo, working backward from the amino acid sequence of the native chicken liver enzyme by PCR amplification of a series of 72 overlapping primers. The recombinant protein displayed the characteristic absorption spectrum of sulfite oxidase and exhibited steady state and rapid kinetic parameters comparable with those of the tissue-derived enzyme. We solved the crystal structures of the wild type and the sulfite oxidase deficiency-causing R138Q (R160Q in humans) variant of recombinant chicken sulfite oxidase in the resting and sulfate-bound forms. Significant alterations in the substrate-binding pocket were detected in the structure of the mutant, and a comparison between the wild type and mutant protein revealed that the active site residue Arg-450 adopts different conformations in the presence and absence of bound sulfate. The size of the binding pocket is thereby considerably reduced, and its position relative to the cofactor is shifted, causing an increase in the distance of the sulfur atom of the bound sulfate to the molybdenum.

  5. Mortality associated with bilirubin levels in insurance applicants.

    PubMed

    Fulks, Michael; Stout, Robert L; Dolan, Vera F

    2009-01-01

    Determine the relationship between bilirubin levels with and without other liver function test (LFT) elevations and relative mortality in life insurance applicants. By use of the Social Security Death Master File mortality was determined in 1,905,664 insurance applicants for whom blood samples were submitted to the Clinical Reference Laboratory. There were 50,174 deaths observed in this study population. Results were stratified by 3 age/sex groups: females, age <60; males, age <60; and all, age 60+. The median follow-up was 12 years. Relative mortality increased as bilirubin decreased below bilirubin levels seen for the middle 50% of the population. The known association of smoking with lower bilirubin values explained only part of the additional elevated risk at low bilirubin levels. In the absence of other LFT elevations, relative mortality remained unchanged as bilirubin increased beyond levels seen for the middle 50% of the population. When a bilirubin elevation was combined with other LFT elevations, mortality further increased only at the highest elevations of other LFTs, seen only in <2.5% of applicants. Isolated elevations of bilirubin in this healthy screening population were not associated with excess mortality but values below the midpoint were. Other investigations have suggested a cardiovascular cause may underlie the excess mortality associated with low bilirubin. In association with other LFT elevations, bilirubin elevation further increases the mortality risk only at the highest elevations of other LFTs.

  6. Photocatabolism of labeled bilirubin in the congenitally jaundiced (Gunn) rat

    PubMed Central

    Ostrow, J. Donald

    1971-01-01

    To elucidate the mechanism by which phototherapy reduces serum bilirubin, studies were performed on the catabolism of labeled bilirubin in homozygous jaundiced Gunn rats before, during, and after a period of exposure to 1700 foot candles of daylight fluorescent light. Following equilibration with the body pool of an intravenously administered tracer dose of 3H- or 14C-bilirubin, radioactive and diazo reactive compounds were excreted in the bile at a slow, steady rate and plasma specific activity declined semilogarithmically. Subsequent exposure to light caused a marked increase in the biliary excretion of radioactive and diazoreactive compounds. Fecal and urinary radioactivity increased also but remained minor fractions of the total excreted radioactivity. After extinguishing the lights, these variables reverted gradually to control values. Spectral and chromotographic analysis of the excreted pigments and their azopigments demonstrated that the increased biliary radioactivity during phototherapy consisted of two roughly equal fractions: (a) unconjugated bilirubin, excreted at rates comparable to the output of conjugated bilirubin in the bile of normal nonjaundiced rats; and (b) water-soluble bilirubin derivatives, chromatographically identical with those found in Gunn rat bile under control lighting conditions but different from the products of photodecomposition of bilirubin in vitro. In some animals, phototherapy produced little decline in plasma bilirubin despite comparable acceleration of bilirubin catabolism. This was attributed tentatively to increased synthesis of early labeled bilirubin in these animals. PMID:5545128

  7. Atazanavir–bilirubin interaction: a pharmacokinetic–pharmacodynamic model

    PubMed Central

    Lozano, Roberto; Domeque, Nieves; Apesteguia, Alberto-Fermin

    2013-01-01

    Purpose The aim of this work was to analyze the atazanavir–bilirubin relationship, using a new mathematical approach to pharmacokinetic–pharmacodynamic models, for competitive drug interactions based on Michaelis–Menten equations. Patients and methods Because atazanavir induces an increase of plasma bilirubin levels, in a concentration-dependent manner, we developed a mathematical model, based on increments of atazanavir and bilirubin concentrations at steady state, in HIV infected (HIV+) patients, and plotted the corresponding nomogram for detecting suboptimal atazanavir exposure. Results By applying the obtained model, the results indicate that an absolute value or an increment of bilirubin at steady state below 3.8 μmol/L, are predictive of suboptimal atazanavir exposure and therapeutic failure. Conclusion We have successfully implemented a new mathematical approach to pharmacokinetic–pharmacodynamic model for atazanavir–bilirubin interaction. As a result, we found that bilirubin plasma levels constitute a good marker of exposure to atazanavir and of viral suppression. PMID:24106429

  8. Preliminary Development of a Fiber Optic Sensor for Measuring Bilirubin

    PubMed Central

    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. PMID:25057239

  9. Prokaryotic orthologues of mitochondrial alternative oxidase and plastid terminal oxidase.

    PubMed

    McDonald, Allison E; Amirsadeghi, Sasan; Vanlerberghe, Greg C

    2003-12-01

    The mitochondrial alternative oxidase (AOX) and the plastid terminal oxidase (PTOX) are two similar members of the membrane-bound diiron carboxylate group of proteins. AOX is a ubiquinol oxidase present in all higher plants, as well as some algae, fungi, and protists. It may serve to dampen reactive oxygen species generation by the respiratory electron transport chain. PTOX is a plastoquinol oxidase in plants and some algae. It is required in carotenoid biosynthesis and may represent the elusive oxidase in chlororespiration. Recently, prokaryotic orthologues of both AOX and PTOX proteins have appeared in sequence databases. These include PTOX orthologues present in four different cyanobacteria as well as an AOX orthologue in an alpha-proteobacterium. We used PCR, RT-PCR and northern analyses to confirm the presence and expression of the PTOX gene in Anabaena variabilis PCC 7120. An extensive phylogeny of newly found prokaryotic and eukaryotic AOX and PTOX proteins supports the idea that AOX and PTOX represent two distinct groups of proteins that diverged prior to the endosymbiotic events that gave rise to the eukaryotic organelles. Using multiple sequence alignment, we identified residues conserved in all AOX and PTOX proteins. We also provide a scheme to readily distinguish PTOX from AOX proteins based upon differences in amino acid sequence in motifs around the conserved iron-binding residues. Given the presence of PTOX in cyanobacteria, we suggest that this acronym now stand for plastoquinol terminal oxidase. Our results have implications for the photosynthetic and respiratory metabolism of these prokaryotes, as well as for the origin and evolution of eukaryotic AOX and PTOX proteins.

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

    SciTech Connect

    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

  11. Bilirubin chemistry, ionization and solubilization by bile salts.

    PubMed

    Ostrow, J D; Celic, L

    1984-01-01

    Bilirubin is a linear tetrapyrrole whose conformation is affected by internal hydrogen bonds formed between the carboxyl side chains and dipyrromethenone rings. Structural variations include: constitutional isomerism of the vinyl or carboxyethyl side chains, geometric isomerism of the methene bridges, tautomerism of the lactam groups, conformational rotations about the central methylene bridge and ionization of one or both carboxyl groups. Aggregation of the dianion into dimers and multimers may occur. The pKa' values of the two carboxyl groups are affected greatly by the environment and may differ widely in micellar solutions like bile. Solubility of bilirubin in water is less than 1 nM at pH = 7 and about 0.1 microM at pH = 8. Nonetheless, it dissolves poorly in most lipid solvents, except for asymmetrical chloroalkanes. Hydrogen bond-breaking solvents, especially dimethyl sulfoxide, are most effective in solubilizing bilirubin. In bile salt solutions, solubility of bilirubin is well above the concentrations of unconjugated bilirubin found in normal human gallbladder bile, and is impaired by lecithin but unaffected by cholesterol. At physiological pH in bile salt solutions, bilirubin is predominantly in its monoanion form that binds readily to the micelles. In such solutions, addition of physiological concentrations of calcium precipitates calcium bilirubinate, leaving residual bilirubin concentrations of up to 15 microM in 50 mM taurocholate or close to the maximum bilirubin concentrations in normal bile. Studies in which disodium bilirubinate is dissolved in bile salt solutions and pH is adjusted to the physiological range reveal that metastable supersaturation with bilirubin may occur and that a mesophase may also form in the presence of lecithin, akin to that seen with cholesterol.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Bilirubin and Stroke Risk Using a Mendelian Randomization Design.

    PubMed

    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) (<10(-7)) including rs6742078 of uridine diphosphoglucuronyl-transferase were selected from genome-wide association study of 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.

  13. Serum bilirubin levels and cardiovascular disease risk: a Janus Bifrons?

    PubMed

    Franchini, Massimo; Targher, Giovanni; Lippi, Giuseppe

    2010-01-01

    This review examines in vitro and in vivo studies, indicating that bilirubin inhibits lipid oxidation and oxygen radical formation. Experimental and epidemiological evidence is presented that suggests that bilirubin may serve as a physiological antioxidant providing protection against cardiovascular disease. Special attention is focused on large prospective studies that noted a strong, inverse relationship between serum bilirubin concentrations and cardiovascular morbidity and mortality even after adjustment for traditional risk factors. Overall, the evidence from these studies suggests that bilirubin, via its antioxidant potential, has antiatherogenic properties, and that serum bilirubin concentrations in the upper portion of the reference interval for the general population may provide some protection against cardiovascular disease, whereas concentrations in the lower portion of the reference interval indicate increased cardiovascular risk.

  14. Conjugated Bilirubin Triggers Anemia by Inducing Erythrocyte Death

    PubMed Central

    Lang, Elisabeth; Gatidis, Sergios; Freise, Noemi F; Bock, Hans; Kubitz, Ralf; Lauermann, Christian; Orth, Hans Martin; Klindt, Caroline; Schuier, Maximilian; Keitel, Verena; Reich, Maria; Liu, Guilai; Schmidt, Sebastian; Xu, Haifeng C; Qadri, Syed M; Herebian, Diran; Pandyra, Aleksandra A; Mayatepek, Ertan; Gulbins, Erich; Lang, Florian; Häussinger, Dieter; Lang, Karl S; Föller, Michael; Lang, Philipp A

    2015-01-01

    Hepatic failure is commonly associated with anemia, which may result from gastrointestinal bleeding, vitamin deficiency, or liver-damaging diseases, such as infection and alcohol intoxication. At least in theory, anemia during hepatic failure may result from accelerated clearance of circulating erythrocytes. Here we show that bile duct ligation (BDL) in mice leads to severe anemia despite increased reticulocyte numbers. Bilirubin stimulated suicidal death of human erythrocytes. Mechanistically, bilirubin triggered rapid Ca2+ influx, sphingomyelinase activation, formation of ceramide, and subsequent translocation of phosphatidylserine to the erythrocyte surface. Consistent with our in vitro and in vivo findings, incubation of erythrocytes in serum from patients with liver disease induced suicidal death of erythrocytes in relation to their plasma bilirubin concentration. Consistently, patients with hyperbilirubinemia had significantly lower erythrocyte and significantly higher reticulocyte counts compared to patients with low bilirubin levels. Conclusion: Bilirubin triggers suicidal erythrocyte death, thus contributing to anemia during liver disease. (Hepatology 2015;61:275–284) PMID:25065608

  15. Conjugated bilirubin in neonates with glucose-6-phosphate dehydrogenase deficiency.

    PubMed

    Kaplan, M; Rubaltelli, F F; Hammerman, C; Vilei, M T; Leiter, C; Abramov, A; Muraca, M

    1996-05-01

    We used a system capable of measuring conjugated bilirubin and its monoconjugated and diconjugated fractions in serum to assess bilirubin conjugation in 29 glucose-6-phosphate dehydrogenase (G6PD)-deficient, term, male newborn infants and 35 control subjects; all had serum bilirubin levels > or = 256 mumol/L (15 mg/dI). The median value for diconjugated bilirubin was lower in the G6PD-deficient neonates than in control subjects (0.06 (range 0.00 to 1.84) vs 0.21 (range 0.00 to 1.02) mumol/L, p = 0.006). Diglucuronide was undetectable in 11 (38.9%) of the G6PD-deficient infants versus 3 (8.6%) of the control subjects (p = 0.015). These findings imply a partial defect of bilirubin conjugation not previously demonstrated in G6PD-deficient newborn infants.

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Bilirubin conjugates of human bile. Isolation of phenylazo derivatives of bile bilirubin

    PubMed Central

    Kuenzle, Clive C.

    1970-01-01

    A method is presented that allows the isolation of eight different phenylazo derivatives of bile bilirubin. In step I of the isolation procedure, three bilirubin fractions (bilirubin fractions 1, 2 and 3) from human hepatic bile are separated by reverse-phase partition chromatography on silicone-treated Celite with the use of a solvent system prepared from butan-1-ol and 5mm-phosphate buffer, pH6.0. Azo coupling is then performed with diazotized aniline. The three azo pigment mixtures are subjected to step II, in which the above chromatography system is used again. With each azo pigment mixture this step brings about the separation of a non-polar and a polar azo pigment fraction (azo 1A and azo 1B, azo 2A and azo 2B, and azo 3A and azo 3B from bilirubin fractions 1, 2 and 3 respectively). Approximately equal amounts of non-polar and polar pigments are obtained from bilirubin fractions 1 and 2, whereas bilirubin fraction 3 yields azo 3B almost exclusively. In step IIIA the non-polar azo pigment fractions are fractionated further by adsorption chromatography on anhydrous sodium sulphate with the use of chloroform followed by a gradient of ethyl acetate in chloroform. Three azo pigments are thus obtained from both azo 2A (azo 2A1, azo 2A2 and azo 2A3) and azo 3A (azo 3A1, azo 3A2 and azo 3A3). The 2A pigments occur in approximately the following proportions: azo 2A1, 90%; azo 2A2, 10%; azo 2A3, traces. The pigments are purified by crystallization, except for the A3 pigments, which are probably degradation products arising from the corresponding A2 pigments. In step IIIB the polar azo pigment fractions are subjected to reverse-phase partition chromatography on silicone-treated Celite with the use of a solvent system prepared from octan-1-ol–di-isopropyl ether–ethyl acetate–methanol–0.2m-acetic acid (1:2:2:3:4, by vol.). Azo pigment fractions 2B and 3B each yield six azo pigments (azo 2B1 to azo 2B6 and azo 3B1 to azo 3B6 respectively) together with small

  18. Trans-Cutaneous Bilirubinometery versus Serum Bilirubin in Neonatal Jaundice.

    PubMed

    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.

  19. The Relationship Between Serum Bilirubin Concentration and Atrial Fibrillation

    PubMed Central

    Demir, Mehmet; Demir, Canan; Uyan, Umut; Melek, Mehmet

    2013-01-01

    Background Several studies have demonstrated that higher serum bilirubin inhibits the inflammation and proliferation of vascular smooth muscle cells; also there is a relationship between serum bilirubin and cardiovascular disease. However, the relationship between bilirubin and atrial fibrillation (AF) is still unknown. In our study, we compared serum bilirubin, between nonvalvular AF patients and controls. Materials and Method One hundred and two patients with nonvalvular chronic AF without any other cardiovascular disease (mean age 62.51 ± 5.88) were included in our study. One hundred age-matched healthy people with sinus rhythm were accepted as control groups (mean age 61.35 ± 5.44). Routine biochemical parameters and serum bilirubin levels were performed. Results No statistically significant difference was found between two groups in terms of basic characteristics. Total, direct and indirect serum bilirubin levels were significantly lower among persons with AF compared to controls (0.82 ± 0.8 vs. 0.48 ± 0.5, 0.30 ± 0.2 vs. 0.19 ± 0.1 and 0.52 ± 0.5 vs. 0.29 ± 0.3 mg/dL; all P < 0.001, respectively). Conclusion As a result, our study revealed a relationship between serum bilirubin and nonvalvular AF.

  20. Influence of assessment site in measuring transcutaneous bilirubin

    PubMed Central

    da Conceição, Cristiane Maria; Dornaus, Maria Fernanda Pellegrino da Silva; Portella, Maria Aparecida; Deutsch, Alice D'Agostini; Rebello, Celso Moura

    2014-01-01

    ABSTRACT Objective: To investigate the influence of the site of measurement of transcutaneous bilirubin (forehead or sternum) in reproducibility of results as compared to plasma bilirubin. Methods: A cohort study including 58 term newborns with no hemolytic disease. Transcutaneous measurements were performed on the forehead (halfway between the headline and the glabella, from the left toward the right side, making consecutive determinations, one-centimeter apart) and the sternum (five measurements, from the suprasternal notch to the xiphoid process with consecutive determinations, one-centimeter apart) using Bilicheck® (SpectRx Inc, Norcross, Georgia, USA). The correlation and agreement between both methods and plasma bilirubin were calculated. Results: There was a strong linear correlation between both determinations of serum bilirubin at the forehead and sternum (r=0.704; p<0.01 and r=0.653; p<0.01, respectively). There was correspondence of the mean values of transcutaneous bilirubin measured on the sternum (9.9±2.2mg/dL) compared to plasma levels (10.2±1.7mg/dL), but both differ from the values measured on the forehead (8.6±2.0mg/dL), p<0.05. Conclusion: In newborn term infants with no hemolytic disease, measuring of transcutaneous bilirubin on the sternum had higher accuracy as compared to serum bilirubin measurement on the forehead. PMID:24728239

  1. Association of abnormal plasma bilirubin with aggressive HCC phenotype

    PubMed Central

    Carr, Brian I.; Guerra, Vito; Giannini, Edoardo G.; Farinati, Fabio; Ciccarese, Francesca; Rapaccini, Gian Ludovico; Marco, Maria Di; Benvegnù, Luisa; Zoli, Marco; Borzio, Franco; Caturelli, Eugenio; Chiaramonte, Maria; Trevisani, Franco

    2014-01-01

    Background Cirrhosis-related abnormal liver function is associated with predisposition to HCC, features in several HCC classification systems and is an HCC prognostic factor. Aims To examine the phenotypic tumor differences in HCC patients with normal or abnormal plasma bilirubin levels. Methods A 2,416 patient HCC cohort was studied and dichotomized into normal and abnormal plasma bilirubin groups. Their HCC characteristics were compared for tumor aggressiveness features, namely blood AFP levels, tumor size, presence of PVT and tumor multifocality. Results In the total cohort, elevated bilirubin levels were associated with higher AFP levels, increased PVT and multifocality and lower survival, despite similar tumor sizes. When different tumor size terciles were compared, similar results were found, even for small tumor size patients. A multiple logistic regression model for PVT or tumor multifocality showed increased OddsRatios for elevated levels of GGTP, bilirubin and AFP and for larger tumor sizes. Conclusions HCC patients with abnormal bilirubin levels had worse prognosis than patients with normal bilirubin. They also had increased incidence of PVT and tumor multifocality and higher AFP levels, in patients with both small and larger tumors. The results show an association between bilirubin levels and indices of HCC aggressiveness. PMID:24787296

  2. Transcutaneous bilirubin nomograms in African neonates

    PubMed Central

    Mabogunje, Cecilia A.; Imosemi, Donald O.; Emokpae, Abieyuwa A.

    2017-01-01

    Background The use of transcutaneous bilirubin (TcB) as a screening tool, based on relevant population-specific nomogram, or proxy for total serum bilirubin (TSB) levels in assessing the risk of subsequent hyperbilirubinemia is supported by several clinical guidelines on the management of neonatal hyperbilirubinemia. However, while TcB has been found to significantly over-estimate TSB in neonates of African-American ancestry, with variations across TcB devices, no nomogram has been specifically reported for this racial group. This study therefore set out to develop TcB nomograms for healthy late pre-term and term black African neonates derived from two widely used bilirubinometers. Methods A retrospective analysis of 12,377 TcB measurements obtained from 6,373 neonates in the first postnatal week, over a period of 48 months using Bilichek and JM-103 bilirubinometers. TcB percentiles were computed from hour-specific TcB values and nomograms developed for each of the screening devices. Predictive ability of the 75th and 95th percentiles to detect significant hyperbilirubinemia was evaluated between 24–96 hours of age. The 95th percentile curve was compared with those from other populations. Results The velocity of TcB rise at 75th and 95th percentiles was generally higher with JM-103 than Bilichek. Both percentiles also peaked at higher TcB levels with JM-103. The 95th percentile for both instruments showed a downward trend as from approximately 114 hours. Both instruments had high negative predictive values across the selected time-epochs and lower discriminatory ability than reported in non-black populations. Conclusions The predictive utility of TcB as a potential screening tool varies across devices in black African neonates with or without risk of significant hyperbilirubinemia, and lower than levels reported in non-black populations. Equipment-specific nomograms should be considered for TcB monitoring in this racial population where TSB is not routinely

  3. [Relationship of bilirubin to diseases caused by increased oxidative stress].

    PubMed

    Vítek, L

    2013-07-01

    Oxidative stress contributes importantly to pathogenesis of numerous civilization diseases, including cardiovascular diseases, cancer, as well as autoimmune and neurodegenerative conditions. Bilirubin is the major product of the heme catabolic pathway in the intravascular compartment. For long time, bilirubin was considered to be only a waste product, however, recent data from the last 2 decades have proved its important antioxidant properties, which contributes to defense against increased oxidative stress. Numerous experimental as well as clinical studies have demonstrated association between low bilirubin concentrations and cardiovascular diseases, diabetes, certain cancers, autoimunne diseases, such as lupus erythematodes, or rheumatoid arthritis or neurological psychiatric disorders, such as schizofrenia. On the other hand, subjects with mildly elevated blood bilirubin levels, typical for Gilbert syndrome, have decreased risk of these diseases.

  4. Photo-isomerization and oxidation of bilirubin in mammals is dependent on albumin binding.

    PubMed

    Goncharova, Iryna; Jašprová, Jana; Vítek, Libor; Urbanová, Marie

    2015-12-01

    The bilirubin (BR) photo-conversion in the human body is a protein-dependent process; an effective photo-isomerization of the potentially neurotoxic Z,Z-BR as well as its oxidation to biliverdin in the antioxidant redox cycle is possible only when BR is bound on serum albumin. We present a novel analytical concept in the study of linear tetrapyrroles metabolic processes based on an in-depth mapping of binding sites in the structure of human serum albumin (HSA). A combination of fluorescence spectroscopy, circular dichroism (CD) spectroscopy, and molecular modeling methods was used for recognition of the binding site for BR, its derivatives (mesobilirubin and bilirubin ditaurate), and the products of the photo-isomerization and oxidation (lumirubin, biliverdin, and xanthobilirubic acid) on HSA. The CD spectra and fluorescent quenching of the Trp-HSA were used to calculate the binding constants. The results of the CD displacement experiments performed with hemin were interpreted together with the findings of molecular docking performed on the pigment-HSA complexes. We estimated that Z,Z-BR and its metabolic products bind on two independent binding sites. Our findings support the existence of a reversible antioxidant redox cycle for BR and explain an additional pathway of the photo-isomerization process (increase of HSA binding capacity; the excess free [unbound] BR can be converted and also bound to HSA).

  5. Methods for determination of conjugated bilirubin in rat faeces.

    PubMed

    Saxerholt, H; Midtvedt, T; Gustafsson, B E

    1984-10-01

    Conjugated bilirubin was prepared from the faeces of germ-free (GF) rats by three different preparative methods. The bilirubin conjugate preparations were coupled with diazotized ethyl anthranilate and the formed ethyl anthranilate azopigments were quantified spectrophotometrically and separated by thin-layer chromatography (tlc). The most polar azopigment was purified by tlc and subjected to ammonolysis followed by tlc of the released saccaride. As a result of this procedure, only glucuronic acid was detected as the conjugating saccaride thus indicating that the most polar azopigment prepared from GF rat faeces was the delta ethyl anthranilate azopigment. Reference azopigments were prepared from GF rat small intestinal contents and subjected to separation by tlc. The azopigment pattern was very similar to the pattern obtained with the faecal azopigment preparations and a maximum of ten separated azopigment spots were detected. The findings indicated that, in addition to bilirubin glucuronides, other bilirubin conjugates with unknown structure are excreted with the faeces of GF rats. One of the preparative methods used for the preparation of conjugated bilirubin from GF rat faeces was tested on faeces from conventional (CONV) rats. From these preparations, no ethyl anthranilate azopigments were formed, thus indicating that faeces from CONV rats is devoid of conjugated bilirubin.

  6. The clinical syndrome of bilirubin-induced neurologic dysfunction.

    PubMed

    Bhutani, Vinod K; Johnson-Hamerman, Lois

    2015-02-01

    Clinicians have hypothesized a spectrum of minor neurologic manifestations, consistent with neuroanatomical reports and collectively termed as a "syndrome of bilirubin-induced neurologic dysfunction (BIND)," which can occur in the absence of classical kernicterus. The current review builds on these initial reports with a focus on clinical signs and symptoms that are assessed by standardized tools and manifest from neonatal age to childhood. These clinical manifestations are characterized by the following domains: (i) neuromotor signs; (ii) muscle tone abnormalities; (iii) hyperexcitable neonatal reflexes; (iv) variety of neurobehavior manifestations; (v) speech and language abnormalities; and (vi) evolving array of central processing abnormalities, such as sensorineural audiology and visuomotor dysfunctions. Concerns remain that the most vulnerable infants are likely to acquire BIND, either because their exposure to bilirubin is not identified as severe enough to need treatment or is prolonged but slightly below current threshold levels for intervention. Knowing that a total serum/plasma bilirubin (TB) level is not the most precise indicator of neurotoxicity, the role of expanded biomarkers or a "bilirubin panel" has yet to be validated in prospective studies. Future studies that correlate early "toxic" bilirubin exposure to long-term academic potential of children are needed to explore new insights into bilirubin's effect on the structural and functional maturation of an infant's neural network topology.

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

    PubMed

    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.

  8. Influence of hemoglobin on non-invasive optical bilirubin sensing

    NASA Astrophysics Data System (ADS)

    Jiang, Jingying; Gong, Qiliang; Zou, Da; Xu, Kexin

    2012-03-01

    Since the abnormal metabolism of bilirubin could lead to diseases in the human body, especially the jaundice which is harmful to neonates. Traditional invasive measurements are difficult to be accepted by people because of pain and infection. Therefore, the real-time and non-invasive measurement of bilirubin is of great significance. However, the accuracy of currently transcutaneous bilirubinometry(TcB) is generally not high enough, and affected by many factors in the human skin, mostly by hemoglobin. In this talk, absorption spectra of hemoglobin and bilirubin have been collected and analyzed, then the Partial Least Squares (PLS) models have been built. By analyzing and comparing the Correlation and Root Mean Square Error of Prediction(RMSEP), the results show that the Correlation of bilirubin solution model is larger than that of the mixture solution added with hemoglobin, and its RMSEP value is smaller than that of mixture solution. Therefore, hemoglobin has influences on the non-invasive optical bilirubin sensing. In next step, it is necessary to investigate how to eliminate the influence.

  9. Chromatographic analysis and structure determination of biliverdins and bilirubins.

    PubMed

    Heirwegh, K P; Fevery, J; Blanckaert, N

    1989-11-10

    Recent applications of thin-layer chromatographic (TLC) and high-performance liquid chromatographic (HPLC) procedures has revealed an unexpected wide variety of naturally occurring unconjugated and conjugated bilirubins. Biliverdins seems to occur only in unconjugated forms, mainly as the IX alpha isomer. Several synthetic biliverdins and bilirubins present interesting models for biochemical and metabolic studies. Owing to recent recognition of the astounding heterogeneity of natural bilirubins and to the various artifactual changes that bile pigments can undergo, considerable confusion has existed, and still exists, with regard to the nomenclature of the bile pigments and their derivatives. To set a background for further discussion, the present review starts with a brief discussion of nomenclature and of the various characteristic forms of lability of the bile pigments. TLC and HPLC procedures for preparation and analysis of unconjugated biliverdins and bilirubins and their methyl ester and sugar ester conjugates, as well as procedures for analysis of bilirubin-protein conjugates, are then discussed. Since, in view of the lability and pronounced heterogeneity of bile pigments, it is important to assess the composition and nature of chromatographically isolated pigments, the review is concluded by a brief evaluation of various structural tests.

  10. Functional polyethersulfone particles for the removal of bilirubin.

    PubMed

    Jiang, Xin; Xiang, Tao; Xie, Yi; Wang, Rui; Zhao, Weifeng; Sun, Shudong; Zhao, Chang-Sheng

    2016-02-01

    In this study, polyethersulfone/poly (glycidyl methacrylate) particles are prepared via in situ cross-linked polymerization coupled with a phase inversion technique. The surfaces of these particles are then further modified by grafting amino groups using tetraethylenepentamine, dethylenetriamine, ethylenediamine, or 1,6-hexanediamine for the removal of bilirubin. The particles are characterized by Flourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. Batch adsorption experiments are performed to verify the adsorption capability, and the effect of bilirubin initial concentration, bovine serum albumin concentration, and solution ionic strength on the adsorption is also investigated. In addition, both adsorption kinetic and isotherm models are applied to analyze the adsorption process of bilirubin, and a particle column is used to further study the bilirubin removal ability.To prove that the method was a universal portal to prepare functional particles, polysulfone, polystyrene, and poly(vinylidene fluoride) based functional particles were also prepared and used for the removal of bilirubin. This study and the results indicated that the particles had a great potential to be used in hemoperfusion treatment for hyperbilirubinemia.

  11. Conjugated bilirubin triggers anemia by inducing erythrocyte death.

    PubMed

    Lang, Elisabeth; Gatidis, Sergios; Freise, Noemi F; Bock, Hans; Kubitz, Ralf; Lauermann, Christian; Orth, Hans Martin; Klindt, Caroline; Schuier, Maximilian; Keitel, Verena; Reich, Maria; Liu, Guilai; Schmidt, Sebastian; Xu, Haifeng C; Qadri, Syed M; Herebian, Diran; Pandyra, Aleksandra A; Mayatepek, Ertan; Gulbins, Erich; Lang, Florian; Häussinger, Dieter; Lang, Karl S; Föller, Michael; Lang, Philipp A

    2015-01-01

    Hepatic failure is commonly associated with anemia, which may result from gastrointestinal bleeding, vitamin deficiency, or liver-damaging diseases, such as infection and alcohol intoxication. At least in theory, anemia during hepatic failure may result from accelerated clearance of circulating erythrocytes. Here we show that bile duct ligation (BDL) in mice leads to severe anemia despite increased reticulocyte numbers. Bilirubin stimulated suicidal death of human erythrocytes. Mechanistically, bilirubin triggered rapid Ca(2+) influx, sphingomyelinase activation, formation of ceramide, and subsequent translocation of phosphatidylserine to the erythrocyte surface. Consistent with our in vitro and in vivo findings, incubation of erythrocytes in serum from patients with liver disease induced suicidal death of erythrocytes in relation to their plasma bilirubin concentration. Consistently, patients with hyperbilirubinemia had significantly lower erythrocyte and significantly higher reticulocyte counts compared to patients with low bilirubin levels. Bilirubin triggers suicidal erythrocyte death, thus contributing to anemia during liver disease. © 2014 The Authors. Hepatology published by Wiley Periodicals, Inc., on behalf of the American Association for the Study of Liver Diseases.

  12. Blood-brain interfaces and bilirubin-induced neurological diseases.

    PubMed

    Ghersi-Egea, J F; Gazzin, S; Strazielle, N

    2009-01-01

    The endothelium of the brain microvessels and the choroid plexus epithelium form highly specialized cellular barriers referred to as blood-brain interfaces through which molecular exchanges take place between the blood and the neuropil or the cerebrospinal fluid, respectively. Within the brain, the ependyma and the pia-glia limitans modulate exchanges between the neuropil and the cerebrospinal fluid. All these interfaces are key elements of neuroprotection and fulfill trophic functions; both properties are critical to harmonious brain development and maturation. By analogy to hepatic bilirubin detoxification pathways, we review the transport and metabolic mechanisms which in all these interfaces may participate in the regulation of bilirubin cerebral bioavailability in physiologic conditions, both in adult and in developing brain. We specifically address the role of ABC and OATP transporters, glutathione-S-transferases, and the potential involvement of glucuronoconjugation and oxidative metabolic pathways. Regulatory mechanisms are explored which are involved in the induction of these pathways and represent potential pharmacological targets to prevent bilirubin accumulation into the brain. We then review the possible alteration of the neuroprotective and trophic barrier functions in the course of bilirubin-induced neurological dysfunctions resulting from hyperbilirubinemia. Finally, we highlight the role of the blood-brain and blood-CSF barriers in regulating the brain biodisposition of candidate drugs for the treatment or prevention of bilirubin-induced brain injury.

  13. Enhanced removal of bilirubin on molecularly imprinted titania film.

    PubMed

    Yang, Zheng-peng; Yan, Jin-long; Zhang, Chun-jing; Luo, Shu-qiong

    2011-10-01

    Titania film imprinted by bilirubin molecule at the surface of quartz crystal was prepared using molecular imprinting and surface sol-gel process. The molecularly imprinted titania film was characterized by FTIR spectra, and the interaction between bilirubin and imprinted film was investigated using quartz crystal microbalance (QCM) technique. Compared with pure titania film, the molecularly imprinted titania film exhibits a much higher adsorption capacity for the target molecule, and the adsorption kinetic parameter estimated from the in situ frequency measurement is about 1.6×10(8) M(-1), which is ten times higher than that obtained on pure titania film. The photocatalytic measurements indicate that the bilirubin adsorbed on molecularly imprinted titania film can be completely removed under UV illumination. Moreover, our study indicates that the molecularly imprinted titania film possesses a better stability and reusability.

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

    PubMed

    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 200mgpyrazole/kg/day for 3days 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. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

  15. Bilirubin oxidation products, oxidative stress, and intracerebral hemorrhage

    PubMed Central

    Clark, J. F.; Loftspring, M.; Wurster, W. L.; Beiler, S.; Beiler, C; Wagner, K. R.; Pyne-Geithman, G. J.

    2009-01-01

    Summary Hematoma and perihematomal regions after intracerebral hemorrhage (ICH) are biochemically active environments known to undergo potent oxidizing reactions. We report facile production of bilirubin oxidation products (BOXes) via hemoglobin/Fenton reaction under conditions approximating putative in vivo conditions seen following ICH. Using a mixture of human hemoglobin, physiological buffers, unconjugated solubilized bilirubin, and molecular oxygen and/or hydrogen peroxide, we generated BOXes, confirmed by spectral signature consistent with known BOXes mixtures produced by independent chemical synthesis, as well as HPLC-MS of BOX A and BOX B. Kinetics are straightforward and uncomplicated, having initial rates around 0.002 μM bilirubin per μM hemoglobin per second under normal experimental conditions. In hematomas from porcine ICH model, we observed significant production of BOXes, malondialdehyde, and superoxide dismutase, indicating a potent oxidizing environment. BOX concentrations increased from 0.084 ± 0.01 in fresh blood to 22.24 ± 4.28 in hematoma at 72 h, and were 11.22 ± 1.90 in adjacent white matter (nmol/g). Similar chemical and analytical results are seen in ICH in vivo, indicating the hematoma is undergoing similar potent oxidations. This is the first report of BOXes production using a well-defined biological reaction and in vivo model of same. Following ICH, amounts of unconjugated bilirubin in hematoma can be substantial, as can levels of iron and hemoglobin. Oxidation of unconjugated bilirubin to yield bioactive molecules, such as BOXes, is an important discovery, expanding the role of bilirubin in pathological processes seen after ICH. PMID:19066073

  16. Galactosaemia: an unusual cause of chronic bilirubin encephalopathy

    PubMed Central

    Sahoo, Tanushree; Thukral, Anu; Agarwal, Ramesh; Sankar, Mari Jeeva

    2015-01-01

    Galactosaemia is a disorder of galactose metabolism in which raised levels of galactose and galactose-1-phosphate damage various organs. Although galactosaemia is a common metabolic liver disease in childhood, it is a rare cause of neonatal hyperbilirubinemia requiring intervention. We report an unusual case of neonatal galactosaemia that at presentation had features of acute bilirubin encephalopathy requiring exchange transfusion and at discharge had features of chronic bilirubin encephalopathy. This case report emphasises the need for timely suspicion and diagnosis of this disease for prevention of chronic morbidity. PMID:25618877

  17. Galactosaemia: an unusual cause of chronic bilirubin encephalopathy.

    PubMed

    Sahoo, Tanushree; Thukral, Anu; Agarwal, Ramesh; Sankar, Mari Jeeva

    2015-01-23

    Galactosaemia is a disorder of galactose metabolism in which raised levels of galactose and galactose-1-phosphate damage various organs. Although galactosaemia is a common metabolic liver disease in childhood, it is a rare cause of neonatal hyperbilirubinemia requiring intervention. We report an unusual case of neonatal galactosaemia that at presentation had features of acute bilirubin encephalopathy requiring exchange transfusion and at discharge had features of chronic bilirubin encephalopathy. This case report emphasises the need for timely suspicion and diagnosis of this disease for prevention of chronic morbidity.

  18. Isolation and purification of the cytochrome oxidase of Azotobacter vinelandii.

    PubMed

    Jurtshuk, P; Mueller, T J; Wong, T Y

    1981-09-14

    A membrane-bound cytochrome oxidase for Azobacter vinelandii was purified 20-fold using a detergent-solubilization procedure. Activity was monitored using as ascorbate-TMPD oxidation assay. The oxidase was 'solubilized' from a sonic-type electron-transport particle (R3 fraction) using Triton X-100 and deoxycholate. Low detergent concentrations first solubilized the flavoprotein oxidoreductases, then higher concentrations of Triton X-100 and KCl solubilized the oxidase, which was precipitated at 27-70% (NH4)2SO4. The highly purified cytochrome oxidase has a V of 60-78 microgatom O consumed/min per mg protein. TMPD oxidation by the purified enzyme was inhibited by CO, KCN, NaN3 and NH2OH; NaNO2 (but not NaNO3) also had a potent inhibitory effect. Spectral analyses revealed two major hemoproteins, the c-type cytochrome c4 and cytochrome o; cytochromes a1 and d were not detected. The Azotobacter cytochrome oxidase is an integrated cytochrome c4-o complex, TMPD-dependent cytochrome oxidase activity being highest in preparations having a high c-type cytochrome content. This TMPD-dependent cytochrome oxidase serves as a major oxygen-activation site for the A. vinelandii respiratory chain. It appears functionally analogous to cytochrome a+a3 oxidase of mammalian mitochondria.

  19. Developmental Onset of Bilirubin-induced Neurotoxicity Involves Toll-like Receptor 2-dependent Signaling in Humanized UDP-glucuronosyltransferase1 Mice*

    PubMed Central

    Yueh, Mei-Fei; Chen, Shujuan; Nguyen, Nghia; Tukey, Robert H.

    2014-01-01

    Biological and signaling events that connect developmentally induced hyperbilirubinemia to bilirubin-induced neurological dysfunction (BIND) and CNS toxicity in humans are poorly understood. In mammals, UDP-glucuronosyltransferase 1A1 (UGT1A1) is the sole enzyme responsible for bilirubin glucuronidation, a rate-limiting step necessary for bilirubin metabolism and clearance. Humanized mice that express the entire UGT1 locus (hUGT1) and the UGT1A1 gene, develop neonatal hyperbilirubinemia, with 8–10% of hUGT1 mice succumbing to CNS damage, a phenotype that is presented by uncontrollable seizures. We demonstrate that neuroinflammation and reactive gliosis are prominent features of bilirubin brain toxicity, and a disturbed redox status resulting from activation of NADPH oxidase is an important contributing mechanism found in BIND. Using knock-out mice and primary brain cells, we connect a key pattern recognition receptor, Toll-like receptor 2 (TLR2), to hyperbilirubinemia-induced signaling. We illustrate a requirement for TLR2 signaling in regulating gliosis, proinflammatory mediators, and oxidative stress when neonatal mice encounter severe hyperbilirubinemia. TLR2-mediated gliosis strongly correlates with pronounced neuroinflammation in the CNS with up-regulation of TNFα, IL-1β, and IL-6, creating a pro-inflammatory CNS environment. Gene expression and immunohistochemistry staining show that hUGT1/Tlr2−/− mice fail to activate glial cells, proinflammatory cytokines, and stress response genes. In addition, bilirubin-induced apoptosis was significantly enhanced by blocking TLR2 signaling indicating its anti-apoptotic property. Consequently, a higher neonatal death rate (57.1%) in hUGT1/Tlr2−/− mice was observed when compared with hUGT1 mice (8.7%). These results suggest that TLR2 signaling and microglia neuroinflammation are linked to a repair and/or protection mode against BIND. PMID:24403077

  20. Interaction of bilirubin with Ag and Au ions: green synthesis of bilirubin-stabilized nanoparticles

    NASA Astrophysics Data System (ADS)

    Shukla, Shashi P.; Roy, Mainak; Mukherjee, Poulomi; Tyagi, A. K.; Mukherjee, Tulsi; Adhikari, Soumyakanti

    2012-07-01

    We report a simple green chemistry to synthesize and stabilize monodispersed silver and gold nanoparticles sols by reducing aqueous solution of the respective metal salts in the presence of bilirubin (BR). No additional capping agent was used in the process of stabilization of the nanoparticles. As a completely new finding, we have observed that BR known to be toxic at higher concentration in one hand and conversely an antioxidant at physiological concentration reduces these metal ions to form the respective metal nanoparticles. Moreover, BR and its oxidized products also serve as capping agents to the nanoparticles. The particles were characterized by transmission electron microscopy. BR and its oxidized products capped nanoparticles are stable for months. The UV-Vis absorption spectra of the silver sol show the plasmon peak of symmetric spherical particles which was further reflected in the TEM images. The sizes of the silver particles were about 5 nm. These silver particles showed reasonably high antibacterial activity in Gram negative wild type E. coli. In the case of interaction of BR with gold ions, we could obtain cubic gold nanoparticles of average sizes 20-25 nm. Possible modes of anchorage of BR and/its oxidized products to silver nanoparticles were demonstrated by surface-enhanced resonance Raman spectroscopy (SERS) that in turn demonstrated the feasibility of using these nanoparticles as SERS substrates.

  1. Ultrafast deactivation of bilirubin: dark intermediates and two-photon isomerization.

    PubMed

    Carreira-Blanco, Carlos; Singer, Patrick; Diller, Rolf; Luis Pérez Lustres, J

    2016-03-14

    Bilirubin is a neurotoxic product responsible for neonatal jaundice, which is generally treated by phototherapy. The photoreaction involves ultrafast internal conversion via an elusive intermediate and Z-E isomerization with minor yield (less than 3% in solution). The structure of the intermediate remains unclear. Here, the combination of UV-vis and mid-IR ultrafast transient absorption spectroscopy reports a comprehensive picture of the mechanism and provides essential structural information about the intermediate species. Thus, spectral dynamics during the earliest ps unveils a wavepacket travelling from the Franck-Condon region to the crossing point with a dark state. The latter shows a tighter molecular skeleton than the ground state and decays with 15 ps time constant. Remarkably, the relative contribution of a non-decaying component increases linearly with pump energy, suggesting that Z-E isomerization could also be triggered by two-photon excitation. Implications for the photochemistry of protein-bound open tetrapyrroles are discussed.

  2. Nanofibrous polymeric beads from aramid fibers for efficient bilirubin removal.

    PubMed

    Peng, Zihang; Yang, Ye; Luo, Jiyue; Nie, Chuanxiong; Ma, Lang; Cheng, Chong; Zhao, Changsheng

    2016-08-16

    Polymer based hemoperfusion has been developed as an effective therapy to remove the extra bilirubin from patients. However, the currently applied materials suffer from either low removal efficiency or poor blood compatibility. In this study, we report the development of a new class of nanofibrous absorbent that exhibited high bilirubin removal efficiency and good blood compatibility. The Kevlar nanofiber was prepared by dissolving micron-sized Kevlar fiber in proper solvent, and the beads were prepared by dropping Kevlar nanofiber solutions into ethanol. Owing to the nanofiborous structure of the Kevlar nanofiber, the beads displayed porous structures and large specific areas, which would facilitate the adsorption of toxins. In the adsorption test, it was noticed that the beads possessed an adsorption capacity higher than 40 mg g(-1) towards bilirubin. In plasma mimetic solutions, the beads still showed high bilirubin removal efficiency. Furthermore, after incorporating with carbon nanotubes, the beads were found to have increased adsorption capacity for human degradation waste. Moreover, the beads showed excellent blood compatibility in terms of a low hemolysis ratio, prolonged clotting times, suppressed coagulant activation, limited platelet activation, and inhibited blood related inflammatory activation. Additionally, the beads showed good compatibility with endothelial cells. In general, the Kevlar nanofiber beads, which integrated with high adsorption capacity, good blood compatibility and low cytotoxicity, may have great potential for hemoperfusion and some other applications in biomedical fields.

  3. Solar Irradiation of Bilirubin: An Experiment in Photochemical Oxidation

    ERIC Educational Resources Information Center

    Pillay A. E.; Salih, F. M.

    2006-01-01

    An experiment in photochemical oxidation, which deals with bilirubin, a well-known light-sensitive biological compound that is pedagogically ideal for photochemical experiments at tertiary institutes, is presented. The experiment would benefit students in chemistry who eventually branch out into the health sciences or biochemistry.

  4. Visual inspection versus spectrophotometry in detecting bilirubin in cerebrospinal fluid

    PubMed Central

    Linn, F; Voorbij, H; Rinkel, G; Algra, A; van Gijn, J

    2005-01-01

    Methods: Clinicians and students assessed CSF specimens with seven degrees of extinction between 0.00 and 0.09 at 450–460 nm as "yellow," "doubtful," or "colourless" after random presentation under standard conditions. The assessments were compared with spectrophotometry, with 0.05 being taken as the cut off level for the presence of bilirubin. Results were compared between the two groups and explored by means of receiver operating characteristic (ROC) curves. Results: All 51 clinicians and 50 of 51 students scored the tubes with extinction of 0.06 or higher as "yellow" or "doubtful." Tubes without any bilirubin were scored as "yellow" by three of the students only. The ROC curves confirmed that the diagnostic properties of the visual inspection versus spectrophotometry were slightly better for the clinicians than for the students. Conclusions: If CSF is considered colourless, the extinction of bilirubin is too low to be compatible with a diagnosis of recent subarachnoid haemorrhage. If CSF is not considered colourless, spectrophotometry should be carried out to determine the level of extinction of bilirubin. PMID:16170095

  5. Solar Irradiation of Bilirubin: An Experiment in Photochemical Oxidation

    ERIC Educational Resources Information Center

    Pillay A. E.; Salih, F. M.

    2006-01-01

    An experiment in photochemical oxidation, which deals with bilirubin, a well-known light-sensitive biological compound that is pedagogically ideal for photochemical experiments at tertiary institutes, is presented. The experiment would benefit students in chemistry who eventually branch out into the health sciences or biochemistry.

  6. Separation of putrescine oxidase and spermidine oxidase in foetal bovine serum with the aid of a specific radioactive assay of spermidine oxidase.

    PubMed Central

    Gahl, W A; Vale, A M; Pitot, H C

    1980-01-01

    1. A sensitive and specific assay for spermidine oxidase is described. The method involves the separation of [14C]spermidine (substrate) from [14C]putrescine (product) and other 14C-labelled products on a Dowex 50 cation-exchange column: 92% of the putrescine applied to the column was eluted by 2.3 M-HCl, but this treatment left 96% of the spermidine bound to the column. Unchanged spermidine could be removed from the column by elution with 6 M-HCl. 2. By means of this assay, foetal and adult bovine serum were each shown to contain spermidine oxidase activity, putrescine being a major product of the oxidation of spermidine by the serum enzymes. 3. In foetal bovine serum, spermidine oxidase activity is separable from putrescine oxidase activity by chromatography on a cadaverine-Sephadex column, by gel filtration and by ion-exchange column chromatography. Putrescine oxidase was purified 1900-fold and spermidine oxidase 130-fold by these procedures. The former oxidized putrescine but not spermidine, and spermidine oxidase exhibited no activity with putrescine as substrate. PMID:7406861

  7. The biliverdin-bilirubin antioxidant cycle of cellular protection: Missing a wheel?

    PubMed

    McDonagh, Antony F

    2010-09-01

    Bilirubin reportedly protects cultured cells from the toxicity of a 10,000-fold molar excess of H(2)O(2). A bilirubin-biliverdin cycling mechanism has been proposed to explain this remarkable effect whereby bilirubin reacts with oxyradicals specifically generating biliverdin, which is then reduced back to bilirubin by NADPH/biliverdin reductase. Chemical evidence for this mechanism was formation of biliverdin during incubation of bilirubin-albumin with 2,2'-azobis(2-amidinopropane) hydrochloride (AAPH) in vitro and the assumption that biliverdin was formed by the reaction of peroxyl radicals with bilirubin. This paper describes spectroscopic studies on the reaction of bilirubin with AAPH in the presence and absence of human serum albumin. Reactions were run in air and also under oxygen-depleted and oxygen-saturated solutions, the former to inhibit peroxyl radical formation, the latter to augment it. The results confirm that degradation of bilirubin, rather than dehydrogenation to biliverdin, predominates in the reaction of bilirubin with peroxyl radicals generated by AAPH thermolysis. They also suggest that biliverdin produced in the presence of albumin is not formed by the reaction of bilirubin with alkyl peroxyl radicals, as previously assumed. The observations undermine the plausibility of the bilirubin-biliverdin recycling mechanism proposed to explain the reported hyperprotective effect of bilirubin on mammalian cells exposed to excess H(2)O(2). Copyright 2010 Elsevier Inc. All rights reserved.

  8. Distant Determination of Bilirubin Distribution in Skin by Multi-Spectral Imaging

    NASA Astrophysics Data System (ADS)

    Saknite, I.; Jakovels, D.; Spigulis, J.

    2011-01-01

    For mapping the bilirubin distribution in bruised skin the multi-spectral imaging technique was employed, which made it possible to observe temporal changes of the bilirubin content in skin photo-types II and III. The obtained results confirm the clinical potential of this technique for skin bilirubin diagnostics.

  9. Determination of bilirubin by thermal lens spectrometry and studies of its transport into hepatic cells

    NASA Astrophysics Data System (ADS)

    Margon, A.; Terdoslavich, M.; Cocolo, A.; Decorti, G.; Passamonti, S.; Franko, M.

    2005-06-01

    The liver is responsible for clearance of bilirubin, the end product of heme catabolism, from the bloodstream. The main aim of our investigation was to determine the role of the carrier protein bilitranslocase in bilirubin uptake into the liver. Our experiments consisted of exposing cell cultures to bilirubin solutions under different conditions and measuring the uptake of bilirubin into the cells. However, since bilirubin is only slightly soluble in aqueous solution (< 70 nM at pH 7.4), we had to use bilirubin concentrations that are far below the limit of detection of the commonly used techniques (e.g. LOD for HPLC with UV-Vis detection \\cong 10 μM). TLS showed up to be a suitable technique for investigation of bilirubin uptake with an LOD of 2 nM. Under basal conditions, bilirubin uptake did not occur. However, increase of cytosolic NADH due to catabolism of specific substrates (e.g. lactate or ethanol) seemed to trigger bilirubin uptake. Furthermore, bilirubin uptake was completely inhibited by addition of specific anti-bilitranslocase antibodies. We can thus infer that, under these conditions, bilitranslocase is the main bilirubin transporter.

  10. Bilirubin exerts pro-angiogenic property through Akt-eNOS-dependent pathway.

    PubMed

    Ikeda, Yasumasa; Hamano, Hirofumi; Satoh, Akiho; Horinouchi, Yuya; Izawa-Ishizawa, Yuki; Kihira, Yoshitaka; Ishizawa, Keisuke; Aihara, Ken-Ichi; Tsuchiya, Koichiro; Tamaki, Toshiaki

    2015-11-01

    Low serum bilirubin levels are associated with the risk of cardiovascular diseases including peripheral artery disease. Bilirubin is known to exert its property such as antioxidant effect or the enhancement of flow-mediated vasodilation, however, bilirubin action on angiogenesis remains unclear. To investigate the molecular mechanism of bilirubin on angiogenic effect, we first employed C57BL/6J mice with unilateral hindlimb ischemia surgery and divided the mice into two groups (vehicle-treated group and bilirubin-treated group). The analysis of laser speckle blood flow demonstrated the enhancement of blood flow recovery in response to ischemia of mice with bilirubin treatment. The density of capillaries was significantly higher in ischemic-adductor muscles of bilirubin-treated mice. The phosphorylated levels of endothelial nitric oxide synthase (eNOS) and Akt were increased in ischemic skeletal muscles of mice with bilirubin treatment compared with vehicle treatment. In in vitro experiments by using human aortic endothelial cells, bilirubin augmented eNOS and Akt phosphorylation, cell proliferation, cell migration and tube formation. These bilirubin actions on endothelial cell activation were inhibited by LY294002, a phosphatidylinositol 3-kinase inhibitor. In conclusion, bilirubin promotes angiogenesis through endothelial cells activation via Akt-eNOS-dependent manner.

  11. In Vitro Determination of Skin Bilirubin Using Chromatic Modulation

    DTIC Science & Technology

    2007-11-02

    bilirubi- nometry: Its role in the assessment of neonatal jaundice ,” Clinical Biochemistry, vol. 30, pp. 1-9, 1997. [4] H. Varley, Practical...serum bilirubin (SB) and a chromatic parameter, namely Hue angle (H). The chromatic TcB results are highly predictive of SB levels in neonatal babies...The proposed chromatic system can be used to make decisions about transfusions or phototherapy in neonates , hence acting as a screening device to

  12. Study on dissolution and disintegration of calcium bilirubinate stone.

    PubMed

    Nakamura, Y; Suzuki, N; Takahashi, W; Sato, T

    1978-06-01

    When a slice of calcium bilirubinate stone was incubated in a solution of tetrasodium salt of ethylendiamine-tetraacetic acid (EDTA.4Na), a potent chelating agent, the solution exhibited a yellow brown tint, which was spectroscopically characteristic of bilirubin. Microscopic examination of the slice revealed dissolution of granules of calcium bilirubinate, leaving behind a reticular matrix of PAS-positive substance. The effect of EDTA.4Na was influenced by pH, being fully effective only at pH 10 or more, and by temperature and concentration as well. Simultaneous application of bile salt enhanced the activity of EDTA.4Na, hydrophilizing the gallstone surface to facilitate chelating reaction and also dissolving minor fatty components of the stone. Heparin at proper concentrations also promoted disintegration of the stone, changing surface potential of its constituent particles to the dispersion-prone charge. The effect of composite EDTA.4Na-bile salt-heparin was thus significantly greater than that of single EDTA.4Na. This mixture is promising for clinical application as a means of direct dissolution of residual gallstones.

  13. Bilirubin oxidation products (BOXes): synthesis, stability and chemical characteristics

    PubMed Central

    Wurster, W. L.; Pyne-Geithman, G. J.; Peat, I. R.; Clark, J. F.

    2009-01-01

    Summary Bilirubin oxidation products (BOXes) have been a subject of interest in neurosurgery because they are purported to be involved in subarachnoid hemorrhage induced cerebral vasospasm. There is a growing body of information concerning their putative role in vasospasm; however, there is a dearth of information concerning the chemical and biochemical characteristics of BOXes. A clearer understanding of the synthesis, stability and characteristics of BOXes will be important for a better understanding of the role of BOXes post subarachnoid hemorrhage. We used hydrogen peroxide to oxidize bilirubin and produce BOXes. BOXes were extracted and analyzed using conventional methods such as HPLC and mass spectrometry. Characterization of the stability BOXes demonstrates that light can photodegrade BOXes with a t1/2 of up to 10 h depending upon conditions. Mixed isomers of BOXes have an apparent extinction coefficient of ε = 6985, and a λmax of 310 nm. BOXes are produced by the oxidation of bilirubin, yielding a mixture of isomers: 4-methyl-5-oxo-3-vinyl-(1,5-dihydropyrrol-2-ylidene)acetamide (BOX A) and 3-methyl-5-oxo-4-vinyl-(1,5-dihydropyrrol-2-ylidene)acetamide (BOX B). The BOXes are photodegraded by ambient light and can be analyzed spectrophotometrically with their extinction coefficient as well as with HPLC or mass spectrometry. Their small molecular weight and photodegradation may have made them difficult to characterize in previous studies. PMID:18456996

  14. Plasma bilirubin level and oxidative stress in preterm infants

    PubMed Central

    Dani, C; Martelli, E; Bertini, G; Pezzati, M; Filippi, L; Rossetti, M; Rizzuti, G; Rubaltelli, F

    2003-01-01

    Objective: To assess the hypothesis that changes in plasma total bilirubin levels (Btot) can influence the antioxidant system and oxidative stress in preterm infants. Methods: Twenty two healthy preterm infants who presented with visible non-haemolytic hyperbilirubinaemia were studied at the mean (SD) age of 3.7 (1.5) days. Btot, plasma total hydroperoxide concentration (TH), plasma protein SH group concentration, and total antioxidant capacity of the plasma (TAC) were measured at study entry and after 24 hours. Results: Btot did not correlate with TH, TAC, or protein SH group concentration, but a significant correlation was found between TH and TAC, TH and protein SH groups, and TAC and protein SH groups, both at study entry and after 24 hours. Conclusion: The decrease in plasma bilirubin was contemporary with an increase in plasma antioxidant capacity and decrease in oxidative stress in preterm infants. This may be the result of the pro-oxidant effect of haem oxygenase, mediated by iron release, which may outcompete the antioxidant properties of bilirubin. PMID:12598500

  15. Plasma bilirubin level and oxidative stress in preterm infants.

    PubMed

    Dani, C; Martelli, E; Bertini, G; Pezzati, M; Filippi, L; Rossetti, M; Rizzuti, G; Rubaltelli, F F

    2003-03-01

    To assess the hypothesis that changes in plasma total bilirubin levels (Btot) can influence the antioxidant system and oxidative stress in preterm infants. Twenty two healthy preterm infants who presented with visible non-haemolytic hyperbilirubinaemia were studied at the mean (SD) age of 3.7 (1.5) days. Btot, plasma total hydroperoxide concentration (TH), plasma protein SH group concentration, and total antioxidant capacity of the plasma (TAC) were measured at study entry and after 24 hours. Btot did not correlate with TH, TAC, or protein SH group concentration, but a significant correlation was found between TH and TAC, TH and protein SH groups, and TAC and protein SH groups, both at study entry and after 24 hours. The decrease in plasma bilirubin was contemporary with an increase in plasma antioxidant capacity and decrease in oxidative stress in preterm infants. This may be the result of the pro-oxidant effect of haem oxygenase, mediated by iron release, which may outcompete the antioxidant properties of bilirubin.

  16. Outward Bound.

    ERIC Educational Resources Information Center

    Outward Bound, Inc., Andover, MA.

    The Outward Bound concept was developed in Germany and Great Britain with the saving of human life as the ultimate goal. Courses are designed to help students discover their true physical and mental limits through development of skills including emergency medical aid, firefighting, search and rescue, mountaineering, and sailing. Five Outward Bound…

  17. Isolated sulfite oxidase deficiency.

    PubMed

    Rupar, C A; Gillett, J; Gordon, B A; Ramsay, D A; Johnson, J L; Garrett, R M; Rajagopalan, K V; Jung, J H; Bacheyie, G S; Sellers, A R

    1996-12-01

    Isolated sulfite oxidase (SO) deficiency is an autosomal recessively inherited inborn error of sulfur metabolism. In this report of a ninth patient the clinical history, laboratory results, neuropathological findings and a mutation in the sulfite oxidase gene are described. The data from this patient and previously published patients with isolated sulfite oxidase deficiency and molybdenum cofactor deficiency are summarized to characterize this rare disorder. The patient presented neonatally with intractable seizures and did not progress developmentally beyond the neonatal stage. Dislocated lenses were apparent at 2 months. There was increased urine excretion of sulfite and S-sulfocysteine and a decreased concentration of plasma cystine. A lactic acidemia was present for 6 months. Liver sulfite oxidase activity was not detectable but xanthine dehydrogenase activity was normal. The boy died of respiratory failure at 32 months. Neuropathological findings of cortical necrosis and extensive cavitating leukoencephalopathy were reminiscent of those seen in severe perinatal asphyxia suggesting an etiology of energy deficiency. A point mutation that resulted in a truncated protein missing the molybdenum-binding site has been identified.

  18. Hepatic disposition and biliary excretion of bilirubin and bilirubin glucuronides in intact rats. Differential processing of pigments derived from intra- and extrahepatic sources.

    PubMed Central

    Crawford, J M; Ransil, B J; Potter, C S; Westmoreland, S V; Gollan, J L

    1987-01-01

    Mechanisms for transport of bilirubin and its conjugates in hepatocytes have not been defined. We investigated the hepatic processing of bilirubin glucuronides and their precursors, and characterized the disposition of bile pigments arising from intraversus extrahepatic sources. Tracer doses of purified radiolabeled biliverdin, bilirubin, bilirubin monoglucuronide (BMG) or diglucuronide (BDG) were administered intravenously to intact normal or jaundiced homozygous Gunn rats. Rapid sequential analysis of radiolabeled BMG and BDG in bile revealed comparable excretion patterns following biliverdin and bilirubin injection, with BDG as the major pigment. Biliary excretion of radiolabeled conjugates from injected BMG was more rapid, with BMG predominating. Excretion of injected BDG in normal rats and BMG or BDG in Gunn rats was virtually identical to that of unaltered BMG in normal rats. Model independent analysis by deconvolution provided objective comparison of the disposition of radiolabeled pigments from the different sources. These findings indicate that bilirubin glucuronides formed in the liver from endogenous (hepatic) and exogenous (extrahepatic) sources of bilirubin follow a similar excretory pathway. BMG formed endogenously is converted preferentially to BDG, whereas circulating BMG is excreted predominantly unchanged. Exogenous conjugated bilirubins are excreted more rapidly than those generated intrahepatically, by a transcellular pathway that is largely independent of the conjugation system. PMID:3558820

  19. Succinate oxidase in Neurospora.

    PubMed

    West, D J; Woodward, D O

    1973-02-01

    Two kinetically distinct states of succinate oxidase have been detected in the mitochondria of Neruospora crassa. One state has a K(m) for succinate of 4.1 x 10(-3)m, and the other has a K(m) for succinate of 3.5 x 10(-4)m. The high K(m) state was found in freshly extracted mitochondria from either 20- or 72-hr mycelium. However, the succinate oxidase activity in mitochondria from 20-hr mycelium rapidly deteriorated in vitro, leaving a stable residual activity with the lower K(m) for succinate. Adenosine triphosphate (ATP) plus Mg(2+) stabilized the high K(m) state in these preparations. The high K(m) state of succinate oxidase was further characterized by a two- to threefold increase in activity over the pH range 6.6 to 8.0 and by classical competitive inhibition by fumarate and malonate. By contrast, the low K(m) state of succinate oxidase showed a relatively flat response to pH over the range 6.6 to 8.0 and a nonclassical pattern of inhibition by fumarate and malonate, as shown by nonlinear plots of reciprocal velocity versus reciprocal substrate concentration in the presence of inhibitor or reciprocal velocity versus inhibitor concentration at fixed substrate concentrations. The relationship of mycelial age to the in vitro stability of succinate oxidase is considered with reference to probable changes in the relative pool sizes of extra- and intramitochondrial ATP in response to changes in the rate of glycolysis.

  20. Effect of bilirubin on the spectrophotometric and radionuclide assay for serum angiotensin-converting enzyme

    SciTech Connect

    Saxe, A.W.; Hollinger, M.A.; Essam, T.

    1986-01-01

    The effect of bilirubin on serum angiotensin-converting enzyme (ACE) activity was studied with spectrophotometric and radionuclide assays. In the spectrophotometric assay addition of bilirubin to normal serum from dog, mouse, and human produced a dose-related inhibition of ACE activity. A 50% decrease in human ACE activity was produced by the addition of approximately 250 mg/L in vitro. Serum from icteric patients with elevated bilirubin was also associated with a reduction in ACE activity in the spectrophotometric assay. A 50% decrease in ACE activity in these samples was associated with a serum bilirubin of approximately 220 mg/L. In the radionuclide assay, however, addition of bilirubin to normal human serum failed to reduce measured ACE activity. The use of a radionuclide assay for serum ACE in clinical samples offers the advantage of less interference from serum bilirubin.

  1. Association between flavonoid-rich fruit and vegetable consumption and total serum bilirubin.

    PubMed

    Loprinzi, Paul D; Mahoney, Sara E

    2015-03-01

    Emerging work demonstrates that serum bilirubin is a novel biomarker implicated in cardiovascular and metabolic diseases. However, we have a limited understanding of the influence of flavonoid-rich fruit and vegetable consumption on bilirubin levels, which was the purpose of this study. Data from the 2003 to 2006 National Health and Nutrition Examination survey were used (n = 1783; 18-85 years of age), with analyses performed in 2014. Total serum bilirubin was measured from a blood sample. Using a food frequency questionnaire (FFQ), a flavonoid index variable was created summing the frequency of consumption of flavonoid-rich foods. After adjustments, greater consumption of flavonoid-rich fruits and vegetables was positively associated with bilirubin levels. Our findings suggest an association between flavonoid-rich fruit and vegetable consumption and bilirubin levels. If confirmed by prospective and experimental studies, then regular consumption of flavonoid-rich fruits and vegetables should be promoted to increase levels of bilirubin.

  2. Factors influencing naproxen metabolite interference in total bilirubin assays.

    PubMed

    Saifee, Nabiha Huq; Ranjitkar, Pratistha; Greene, Dina N

    2016-04-01

    The factors influencing naproxen metabolite O-desmethylnaproxen (ODMN) positive interference in diazo-based Jendrassik and Grof (JG) total bilirubin (Tbil) assays and lack of interference in direct bilirubin (Dbil) assays have not been resolved. The objective of this study was to understand the conditions causing this interference pattern. Pooled normal and ultra-filtered plasma samples spiked with ODMN and naproxen were measured on the Beckman Coulter DxC and AU instruments. Absorbance spectra were obtained for ODMN mixed with Dbil reagent at original and adjusted pH. Absorbance spectra were also obtained for ODMN and bilirubin samples mixed with Tbil assay reagents. ODMN produces a positive interference in the DxC JG Tbil assays, but not the AU Tbil or Dbil assays or the DxC Dbil assay. Neutralizing the acidic pH of AU and DxC Dbil reagents allows ODMN to react with diazo salts. ODMN samples mixed with DxC and AU Tbil reagents produce broad peaks from 450 to 560nm and 400 to 540nm, respectively. The DxC JG Tbil assay monitors a change in absorbance at 520nm close to peak absorbance wavelength of diazo-reacted ODMN, whereas the AU Tbil assay monitors a change in absorbance at 570/660nm, beyond the peak absorbance wavelengths of diazo-reacted ODMN. The acidic pH of diazo-based Dbil assay reagents inhibits the reaction of ODMN with diazo salts. The AU JG Tbil assay is a reliable method to measure Tbil in the setting of naproxen overdose. Copyright © 2015 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  3. Isolated sulfite oxidase deficiency.

    PubMed

    Relinque, B; Bardallo, L; Granero, M; Jiménez, P J; Luna, S

    2015-03-10

    Sulfite oxidase deficiency is an uncommon metabolic disease. Only few cases of its isolated form have been reported in the literature. We report a case of severe neonatal onset. A newborn baby of 41 weeks gestational age, weighted at birth of 3240 grams and had an Apgar score of 6-10-10. Fifty-three hours after being born, the baby started with seizures that were refractory to antiepileptic treatment. Brain function was monitored using a-EEG. Laboratory and imaging tests were performed. All of them were consistent with sulfite oxidase deficiency. The diagnosis was confirmed by genetic testing. We highlight the importance of this disease as part of the differential diagnosis of seizures during the neonatal period, as well as the importance of the therapeutic support based on dietary restrictions. It's also remarkable the possibility of prenatal diagnosis by quantifying enzyme activity and it's also possible carrying out DNA mutational analysis.

  4. A Conserved Steroid Binding Site in Cytochrome c Oxidase

    SciTech Connect

    Qin, Ling; Mills, Denise A.; Buhrow, Leann; Hiser, Carrie; Ferguson-Miller, Shelagh

    2010-09-02

    Micromolar concentrations of the bile salt deoxycholate are shown to rescue the activity of an inactive mutant, E101A, in the K proton pathway of Rhodobacter sphaeroides cytochrome c oxidase. A crystal structure of the wild-type enzyme reveals, as predicted, deoxycholate bound with its carboxyl group at the entrance of the K path. Since cholate is a known potent inhibitor of bovine oxidase and is seen in a similar position in the bovine structure, the crystallographically defined, conserved steroid binding site could reveal a regulatory site for steroids or structurally related molecules that act on the essential K proton path.

  5. Studies on the chemico-biological characteristics of bilirubin binding with collagen.

    PubMed

    Nagarajan, Usharani; Christopher, Jayakumar Gladstone; Jonnalagadda, Raghava Rao; Chandrasekaran, Bangaru; Balachandran, Unni Nair

    2013-12-01

    The clinical impact of bilirubin on collagen is investigated using various physical, chemical and biological methods. Thermo gravimetric analysis and differential scanning analysis of collagen-bilirubin complex matrices indicate that crosslinking does not alter their thermal behavior of collagen. The polydispersity of collagen-bilirubin complex increases in the reacting medium suggesting that there is an increase in the number of interacting points between them. Based on the zeta potential values, the rate of mobility of interacted complex decreases by inferring the extent of binding compared to the control collagen. Emission intensity begins to increase with increase in concentration of bilirubin which ascribes the conformational changes around the aromatic amino acids in collagen. Binding is indicated by an increase in resonance units and the responses are corrected by subtraction of those obtained for native collagen. Bilirubin showed a higher affinity for collagen at a concentration of about 25 nM/mg. In this study, the association rate has been calculated which depicts the increased affinity of bilirubin to collagen. Affinity for bilirubin to collagen has been found to be 8.89×10(-3) s(-1). The greater part of binding of bilirubin to collagen is found to be electrostatic in nature. The investigation leads to comprehend the affinity of collagen-bilirubin complex during jaundice diseased tissues.

  6. 21 CFR 862.1115 - Urinary bilirubin and its conjugates (nonquantitative) test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1115 Urinary bilirubin and its conjugates (nonquantitative) test...

  7. 21 CFR 862.1115 - Urinary bilirubin and its conjugates (nonquantitative) test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1115 Urinary bilirubin and its conjugates (nonquantitative) test...

  8. 21 CFR 862.1115 - Urinary bilirubin and its conjugates (nonquantitative) test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1115 Urinary bilirubin and its conjugates (nonquantitative) test...

  9. 21 CFR 862.1115 - Urinary bilirubin and its conjugates (nonquantitative) test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1115 Urinary bilirubin and its conjugates (nonquantitative) test...

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

    PubMed

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

    2015-05-28

    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.

  11. The kinetics of oxidation of bilirubin and ascorbic acid in solution

    NASA Astrophysics Data System (ADS)

    Solomonov, A. V.; Rumyantsev, E. V.; Kochergin, B. A.; Antina, E. V.

    2012-07-01

    The results of a comparative study of the oxidation of bilirubin, ascorbic acid, and their mixture in aqueous solutions under the action of air oxygen and hydrogen peroxide are presented. The observed and true rate constants for the oxidation reactions were determined. It was shown that the oxidation of tetrapyrrole pigment occurred under these conditions bypassing the stage of biliverdin formation to monopyrrole products. Simultaneous oxidation of bilirubin and ascorbic acid was shown to be accompanied by the inhibition of ascorbic acid oxidation by bilirubin, whereas ascorbic acid itself activated the oxidation of bilirubin.

  12. Unconjugated bilirubin mediates heme oxygenase-1-induced vascular benefits in diabetic mice.

    PubMed

    Liu, Jian; Wang, Li; Tian, Xiao Yu; Liu, Limei; Wong, Wing Tak; Zhang, Yang; Han, Quan-Bin; Ho, Hing-Man; Wang, Nanping; Wong, Siu Ling; Chen, Zhen-Yu; Yu, Jun; Ng, Chi-Fai; Yao, Xiaoqiang; Huang, Yu

    2015-05-01

    Heme oxygenase-1 (HO-1) exerts vasoprotective effects. Such benefit in diabetic vasculopathy, however, remains unclear. We hypothesize that bilirubin mediates HO-1-induced vascular benefits in diabetes. Diabetic db/db mice were treated with hemin (HO-1 inducer) for 2 weeks, and aortas were isolated for functional and molecular assays. Nitric oxide (NO) production was measured in cultured endothelial cells. Hemin treatment augmented endothelium-dependent relaxations (EDRs) and elevated Akt and endothelial NO synthase (eNOS) phosphorylation in db/db mouse aortas, which were reversed by the HO-1 inhibitor SnMP or HO-1 silencing virus. Hemin treatment increased serum bilirubin, and ex vivo bilirubin treatment improved relaxations in diabetic mouse aortas, which was reversed by the Akt inhibitor. Biliverdin reductase silencing virus attenuated the effect of hemin. Chronic bilirubin treatment improved EDRs in db/db mouse aortas. Hemin and bilirubin reversed high glucose-induced reductions in Akt and eNOS phosphorylation and NO production. The effect of hemin but not bilirubin was inhibited by biliverdin reductase silencing virus. Furthermore, bilirubin augmented EDRs in renal arteries from diabetic patients. In summary, HO-1-induced restoration of endothelial function in diabetic mice is most likely mediated by bilirubin, which preserves NO bioavailability through the Akt/eNOS/NO cascade, suggesting bilirubin as a potential therapeutic target for clinical intervention of diabetic vasculopathy.

  13. Cholesterol oxidase: sources, physical properties and analytical applications.

    PubMed

    MacLachlan, J; Wotherspoon, A T; Ansell, R O; Brooks, C J

    2000-04-01

    Since Flegg (H.M. Flegg, An investigation of the determination of serum cholesterol by an enzymatic method, Ann. Clin. Biochem. 10 (1973) 79-84) and Richmond (W. Richmond, The development of an enzymatic technique for the assay of cholesterol in biological fluids, Scand. J. clin. Lab. Invest. 29 (1972) 25; W. Richmond, Preparation and properties of a bacterial cholesterol oxidase from Nocardia sp. and its application to enzyme assay of total cholesterol in serum, Clinical Chemistry 19 (1973) 1350-1356) first illustrated the suitability of cholesterol oxidase (COD) for the analysis of serum cholesterol, COD has risen to become the most widely used enzyme in clinical laboratories with the exception of glucose oxidase (GOD). The use is widespread because assays incorporating the enzyme are extremely simple, specific, and highly sensitive and thus offer distinct advantages over the Liebermann-Burchard analytical methodologies which employ corrosive reagents and can be prone to unreliable results due to interfering substances such as bilirubin. Individuals can now readily determine their own serum cholesterol levels with a simple disposable test kit. This review discusses COD in some detail and includes the topics: (1) The variety of bacterial sources available; (2) The various extraction/purification protocols utilised in order to obtain protein of sufficient clarification (purity) for use in food/clinical analysis; (3) Significant differences in the properties of the individual enzymes; (4) Substrate specificities of the various enzymes; (5) Examples of biological assays which have employed cholesterol oxidase as an integral part of the analysis, and the various assay protocols; (6) New steroidal products of COD. This review is not a comprehensive description of published work, but is intended to provide an account of recent and current research, and should promote further interest in the application of enzymes to analytical selectivity.

  14. Bilirubin as an antioxidant: kinetic studies of the reaction of bilirubin with peroxyl radicals in solution, micelles, and lipid bilayers.

    PubMed

    Hatfield, Gillian L; Barclay, L Ross C

    2004-05-13

    Bilirubin (BR) showed very weak antioxidant activity in a nonpolar medium of styrene or cumene in chlorobenzene. In contrast, BR exhibited strong antioxidant activity in polar media such as aqueous lipid bilayers or SDS micelles/methyl linoleate (pH 7.4), where the rate with peroxyl radicals, k(inh) = 5.0 x 10(4) M(-)(1) s(-)(1), was comparable to that with vitamin E analogues, Trolox, or PMHC. An electron-transfer mechanism accounts for the effect of the medium on the antioxidant properties of BR.

  15. Clinical decision limits for interpretation of direct bilirubin--a CALIPER study of healthy multiethnic children and case report reviews.

    PubMed

    Devgun, Manjit S; Chan, Man Khun; El-Nujumi, Adil M; Abara, Rosemary; Armbruster, David; Adeli, Khosrow

    2015-01-01

    Measurement of total and direct bilirubin is routinely performed for the differential diagnosis of hyperbilirubinemias. The diagnostic efficiency of a test is dependent on the chosen clinical decision limit. This study is designed to address the clinical decision limits for direct bilirubin. Routine laboratory method was used to measure total and direct bilirubin in children up to the age of 18years. Case study data and serum from a group of healthy children were analyzed and statistical exercise was performed to establish decision limits. The reference interval for total bilirubin was 1-12μmol/L and for direct bilirubin 1-9μmol/L with the median direct bilirubin of 3μmol/L. In 17% of children with non-pathological jaundice, median total bilirubin was 173μmol/L, median direct bilirubin was 8μmol/L and median direct bilirubin percent was 49%. From birth direct bilirubin percentage decreased until total bilirubin was 41μmol/L, then it remained at ≤10%. Albumin increased with age, and was on average 2.4g/L higher when measured using bromocresol-green compared with bromocresol-purple. An increased amount of direct bilirubin was observed when albumin (detected using the bromocresol-purple method) was >35g/L. Direct bilirubin concentration of ≥10μmol/L should be used to consider the presence of conjugated hyperbilirubinemia provided that total bilirubin is also above the reference interval. A high direct bilirubin percentage is unlikely to offer any clinical value when total bilirubin is not increased. It is, however, a useful diagnostic tool when there is a persistence of hyperbilirubinemia or when total bilirubin increases during times of stress with direct bilirubin >10%. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

  16. Limitations and opportunities of whole blood bilirubin measurements by GEM premier 4000®.

    PubMed

    Wang, Li; Albert, Arianne Y K; Jung, Benjamin; Hadad, Keyvan; Lyon, Martha E; Basso, Melanie

    2017-03-29

    Neonatal hyperbilirubinemia has traditionally been screened by either total serum bilirubin or transcutaneous bilirubin. Whole blood bilirubin (TwB) by the GEM Premier 4000® blood gas analyzer (GEM) is a relatively new technology and it provides fast bilirubin results with a small sample volume and can measure co-oximetry and other analytes. Our clinical study was to evaluate the reliability of TwB measured by the GEM and identify analytical and clinical factors that may contribute to possible bias. 440 consecutive healthy newborn samples that had plasma bilirubin ordered for neonatal hyperbilirubinemia screening were included. TwB was first measured using the GEM, after which the remainder of the blood was spun and plasma neonatal bilirubin was measured using the VITROS 5600® (VITROS). 62 samples (14%) were excluded from analysis due to failure in obtaining GEM results. Passing-Bablok regression suggested that the GEM results were negatively biased at low concentrations of bilirubin and positively biased at higher concentrations relative to the VITROS results (y = 1.43x-61.13). Bland-Altman plots showed an overall negative bias of the GEM bilirubin with a wide range of differences compared to VITROS. Both hemoglobin concentration and hemolysis affected the accuracy of the GEM results. Clinically, male infants had higher mean bilirubin levels, and infants delivered by caesarean section had lower hemoglobin levels. When comparing the number of results below the 40th percentile and above the 95th percentile cut-offs in the Bhutani nomogram which would trigger discharge or treatment, GEM bilirubin exhibited poor sensitivity and poor specificity in contrast to VITROS bilirubin. An imperfect correlation was observed between whole blood bilirubin measured on the GEM4000® and plasma bilirubin on the VITROS 5600®. The contributors to the observed differences between the two instruments were specimen hemolysis and the accuracy of hemoglobin measurements, the latter

  17. Development of bilirubin transport and metabolism in the newborn rhesus monkey.

    PubMed

    Gartner, L M; Lee, K S; Vaisman, S; Lane, D; Zarafu, I

    1977-04-01

    Hepatic transport and metabolism of bilirubin have been examined in term, premature, and postmature newborn Macaca mulatta (rhesus) monkeys with and without prior phenobarbital treatment of pregnant mother and neonate. In untreated neonates a biphasic pattern of physiologic unconjugated hyperbilirubinemia has been observed. Phase I was characterized by a rapid increase in serum bilirubin concentration to 4.5 mg/dl by 19 hours and an equally rapid decline to 1.0 mg/dl by 48 hours of age. Phase II was characterized by a stable elevation at 1.0 mg/dl (four times greater than in the adult) from 48 to 96 hourse of age, followed by a decline to normal adult concentrations thereafter. An identical pattern was observed in 29 normal, term human neonates, but the duration of each phase was approximately three times as long as that in the monkey. Phase I hyperbilirubinemia appears to result from a sixfold increase in bilirubin load presented to the liver in the neonatal period, combined with marked deficieny in hepatic bilirubin conjugation, the rate-limiting step during Phase I. Hepatic uptake of bilirubin is not rate limiting during Phase I but may contribute to Phase II hyperbilirubinemia. An increased bilirubin load persists throughout the first 19 days of life in the monkey. Phase I physiologic jaundice in the monkey neonate was completely eliminated by prenatal maternal and neonatal administration of phenobarbital. A threefold enhancement of hepatic conjugation of bilirubin (glucuronyl transferase activity) during Phase I entirely accounted for the prevention of hyperbilirubinemia. The bilirubin load was unaffected by administration of phenobarbital. Whereas in control neonates the bilirubin load slightly exceeded hepatic bilirubin conjugating capacity and resulted in retention of bilirubin, in phenobarbital-treated neonates, hepatic conjugating capacity slightly exceeded that required for the bilirubin load. Administration of phenobarbital failed to alter Phase II

  18. Bilirubin inhibits iNOS expression and NO production in response to endotoxin in rats.

    PubMed

    Wang, Weizheng W; Smith, Darcey L H; Zucker, Stephen D

    2004-08-01

    The inducible isoform of heme oxygenase (HO), HO-1, has been shown to play an important role in attenuating tissue injury. Because HO-1 catalyzes the rate-limiting step in bilirubin synthesis, we examined the hypothesis that bilirubin is a key mediator of HO-1 cytoprotection, employing a rat model of endotoxemia. Bilirubin treatment resulted in improved survival and attenuated liver injury in response to lipopolysaccharide infusion. Serum levels of NO and tumor necrosis factor alpha, key mediators of endotoxemia, and hepatic inducible nitric oxide synthase (iNOS) expression were significantly lower in bilirubin-treated rodents versus control animals. Both intraperitoneal and local administration of bilirubin also was found to ameliorate hindpaw inflammation induced by the injection of lambda-carrageenan. Consistent with in vivo results, bilirubin significantly inhibited iNOS expression and suppressed NO production in lipopolysaccharide (LPS)-stimulated RAW 264.7 murine macrophages. In contrast, bilirubin treatment induced a threefold increase in LPS-mediated prostaglandin synthesis in the absence of significant changes in cyclooxygenase expression or activity, suggesting that bilirubin enhances substrate availability for eicosanoid synthesis. Bilirubin had no effect on LPS-mediated activation of nuclear factor kappaB or p38 mitogen-activated protein kinase, consistent with a nuclear factor kappaB-independent mechanism of action. Taken together, these data support a cytoprotective role for bilirubin that is mediated, at least in part, through the inhibition of iNOS expression and, potentially, through stimulation of local prostaglandin E2 production. In conclusion, our findings suggest a role for bilirubin in mollifying tissue injury in response to inflammatory stimuli and support the possibility that the phenomenon of "jaundice of sepsis" represents an adaptive physiological response to endotoxemia. Supplementary material for this article can be found on the

  19. Low serum bilirubin concentration is associated with coronary artery calcification (CAC).

    PubMed

    Tanaka, Muhei; Fukui, Michiaki; Tomiyasu, Ki-ichiro; Akabame, Satoshi; Nakano, Koji; Hasegawa, Goji; Oda, Yohei; Nakamura, Naoto

    2009-09-01

    Bilirubin is a potent antioxidant and previous studies have reported the relationship between low serum bilirubin concentration and atherosclerosis. The purpose of this study was to assess the correlation between serum bilirubin concentration and coronary artery calcification (CAC). This study consisted of 637 participants and we evaluated the relationship between CAC score determined by multislice computed tomography and serum bilirubin concentration. An inverse correlation was found between serum bilirubin concentration and log(CAC+1) (r=-0.361, P<0.0001). Multiple regression analysis also demonstrated that age (beta=0.261, P=0.0125), systolic blood pressure (beta=0.153, P=0.0237), uric acid (beta=0.126, P=0.0441), estimated glomerular filtration rate (beta=-0.139, P=0.0416) and serum bilirubin concentration (beta=-0.281, P<0.0001) were independent determinants of log(CAC+1). An increment of 1 micromol/L in serum bilirubin concentration was associated with 14% decrease in the odds for CAC score > or =400 after adjustment for several risk factors. Both age and SBP were also positively associated with CAC score > or =400, but the odds ratio for CAC score > or =400 was greater for every 1 micromol/L increment in serum bilirubin concentration than for every 1-year increment in age and 1-mmHg increment in SBP. Low serum bilirubin concentration is associated with coronary artery calcification. Serum bilirubin concentration can be measured easily in the clinical laboratory and applied in medical practice, and low serum bilirubin concentration would be useful as a provisional new risk factor of CAC.

  20. Positive Root Bounds and Root Separation Bounds

    NASA Astrophysics Data System (ADS)

    Herman, Aaron Paul

    In this thesis, we study two classes of bounds on the roots of a polynomial (or polynomial system). A positive root bound of a polynomial is an upper bound on the largest positive root. A root separation bound of a polynomial is a lower bound on the distance between the roots. Both classes of bounds are fundamental tools in computer algebra and computational real algebraic geometry, with numerous applications. In the first part of the thesis, we study the quality of positive root bounds. Higher quality means that the relative over-estimation (the ratio of the bound and the largest positive root) is smaller. We find that all known positive root bounds can be arbitrarily bad. We then show that a particular positive root bound is tight for certain important classes of polynomials. In the remainder of the thesis, we turn to root separation bounds. We observe that known root separation bounds are usually very pessimistic. To our surprise, we also find that known root separation bounds are not compatible with the geometry of the roots (unlike positive root bounds). This motivates us to derive new root separation bounds. In the second part of this thesis, we derive a new root separation for univariate polynomials by transforming a known bound into a new improved bound. In the third part of this thesis, we use a similar strategy to derive a new improved root separation bound for polynomial systems.

  1. Clinical system model for monitoring the physiological status of jaundice by extracting bilirubin components from skin diffuse reflectance spectra

    NASA Astrophysics Data System (ADS)

    Kumar, Alla S.; Clark, Joseph; Beyette, Fred R., Jr.

    2009-02-01

    Neonatal jaundice is a medical condition which occurs in newborns as a result of an imbalance between the production and elimination of bilirubin. The excess bilirubin in the blood stream diffuses into the surrounding tissue leading to a yellowing of the skin. As the bilirubin levels rise in the blood stream, there is a continuous exchange between the extra vascular bilirubin and bilirubin in the blood stream. Exposure to phototherapy alters the concentration of bilirubin in the vascular and extra vascular regions by causing bilirubin in the skin layers to be broken down. Thus, the relative concentration of extra vascular bilirubin is reduced leading to a diffusion of bilirubin out of the vascular region. Diffuse reflectance spectra from human skin contains physiological and structural information of the skin and nearby tissue. A diffuse reflectance spectrum must be captured before and after blanching in order to isolate the intravascular and extra vascular bilirubin. A new mathematical model is proposed with extra vascular bilirubin concentration taken into consideration along with other optical parameters in defining the diffuse reflectance spectrum from human skin. A nonlinear optimization algorithm has been adopted to extract the optical properties (including bilirubin concentration) from the skin reflectance spectrum. The new system model and nonlinear algorithm have been combined to enable extraction of Bilirubin concentrations within an average error of 10%.

  2. Ammonia-induced energy disorders interfere with bilirubin metabolism in hepatocytes.

    PubMed

    Wang, Qiongye; Wang, Yanfang; Yu, Zujiang; Li, Duolu; Jia, Bin; Li, Jingjing; Guan, Kelei; Zhou, Yubing; Chen, Yanling; Kan, Quancheng

    2014-08-01

    Hyperammonemia and jaundice are the most common clinical symptoms of hepatic failure. Decreasing the level of ammonia in the blood is often accompanied by a reduction in bilirubin in patients with hepatic failure. Previous studies have shown that hyperammonemia can cause bilirubin metabolism disorders, however it is unclear exactly how hyperammonemia interferes with bilirubin metabolism in hepatocytes. The purpose of the current study was to determine the mechanism or mechanisms by which hyperammonemia interferes with bilirubin metabolism in hepatocytes. Cell viability and apoptosis were analyzed in primary hepatocytes that had been exposed to ammonium chloride. Mitochondrial morphology and permeability were observed and analyzed, intermediates of the tricarboxylic acid (TCA) cycle were determined and changes in the expression of enzymes related to bilirubin metabolism were analyzed after ammonia exposure. Hyperammonemia inhibited cell growth, induced apoptosis, damaged the mitochondria and hindered the TCA cycle in hepatocytes. This led to a reduction in energy synthesis, eventually affecting the expression of enzymes related to bilirubin metabolism, which then caused further problems with bilirubin metabolism. These effects were significant, but could be reversed with the addition of adenosine triphosphate (ATP). This study demonstrates that ammonia can cause problems with bilirubin metabolism by interfering with energy synthesis.

  3. Relationship of Bilirubin Levels in Infancy to Later Intellectual Development. Interim Report No. 20.

    ERIC Educational Resources Information Center

    Rubin, Rosalyn A.; And Others

    The relationship of bilirubin (a red bile pigment that is sometimes found in the urine and occurs in the blood and tissues in jaundice) in infancy to later intellectual development was investigated in 241 infants with moderately elevated and high bilirubin levels. Ss were administered motor, psycholinguistic, and intelligence tests at age 8…

  4. Relationship of Bilirubin Levels in Infancy to Later Intellectual Development. Interim Report No. 20.

    ERIC Educational Resources Information Center

    Rubin, Rosalyn A.; And Others

    The relationship of bilirubin (a red bile pigment that is sometimes found in the urine and occurs in the blood and tissues in jaundice) in infancy to later intellectual development was investigated in 241 infants with moderately elevated and high bilirubin levels. Ss were administered motor, psycholinguistic, and intelligence tests at age 8…

  5. Metabolism of bilirubin by human cytochrome P450 2A6

    SciTech Connect

    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.

    2012-05-15

    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 CYP2

  6. Metabolism of heme and bilirubin in rat and human small intestinal mucosa.

    PubMed Central

    Hartmann, F; Bissell, D M

    1982-01-01

    Formation of heme, bilirubin, and bilirubin conjugates has been examined in mucosal cells isolated from the rat upper small intestine. Intact, viable cells were prepared by enzymatic dissociation using a combined vascular and luminal perfusion and incubated with an isotopically labeled precursor, delta-amino-[2,3-3H]levulinic acid. Labeled heme and bile pigment were formed with kinetics similar to those exhibited by hepatocytes. Moreover, the newly formed bilirubin was converted rapidly to both mono- and diglucuronide conjugates. In addition, cell-free extracts of small intestinal mucosa from rats or humans exhibited a bilirubin-UDP-glucuronyl transferase activity that was qualitatively similar to that present in liver. The data suggest that the small intestinal mucosa normally contributes to bilirubin metabolism. PMID:6806320

  7. The effect of oral contraceptive steroids on bile secretion and bilirubin Tm in rats

    PubMed Central

    Heikel, T. A. J.; Lathe, G. H.

    1970-01-01

    1. The effect of oestrogens and progestogens and their 17α-ethinyl derivatives on bile flow, maximum rate of bilirubin secretion, serum and liver bilirubin has been studied. 2. Both 17α-ethinyl substituted oestrogens and progestogens greatly reduced the basal bile flow. The parent compounds, oestradiol-17β and 19-nortestosterone had little or no effect. 3. A much larger dose of progestogens (40 mg/kg) than oestrogens (5 mg/kg) was needed. 4. Between 12 and 48 h were required for 17α-ethinyloestradiol to produce the effect. 5. Bilirubin maximum secretion rate (Tm) was little affected, the only significant reduction being produced by the 3-methyl ether of 17α-ethinyloestradiol (mestranol). 6. Rises in serum conjugated bilirubin following infusion of bilirubin were produced by 17α-ethinyloestradiol and mestranol but not by the progestogens. PMID:5441412

  8. [The influence of bilirubin on the mechanogram of isolated, spontaneously beating frog heart].

    PubMed

    Mittelstädt, U; Biester, J; Sandhage, K

    1976-06-08

    It was shown that bilirubin in its unconjugated form does not only harm the central nervous system. Clinical observations indicate that the toxic effect under certain conditions affects also the heart. In a simple experimental model the influence of free bilirubin on the activity of the heart was investigated. In 69 adult frogs the heart was isolated and exposed sequentially to solutions of different bilirubin concentrations while the heart actions were registered. There was no significant change in the activity of the heart under the influence of bilirubin although concentrations were reached which according to the results of other authors harm cell cultures or evoke in the newborn disturbances in various organs. As a possible explanation, the nonsusceptibility of the heart muscle to bilirubin, the short duration of exposure, and the different behavior of newborn and adult organs is discussed.

  9. Mutual structural effect of bilirubin and model membranes by vibrational circular dichroism.

    PubMed

    Novotná, Pavlína; Goncharova, Iryna; Urbanová, Marie

    2014-03-01

    In this study, vibrational circular dichroism (VCD) spectroscopy was employed for the first time to study the bilirubin (BR) interaction with model membranes and models for membrane proteins. An enantioselective interaction of BR with zwitterionic 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and sphingomyelin (SPM) liposomes was observed by VCD and electronic circular dichroism (ECD) complemented by absorption and fluorescence spectroscopy. The M-form of BR was preferentially recognized in the BR/DMPC system at concentration above 1×10(-4)M, for lower concentrations the P-form of BR was recognized by the DMPC liposomes. The VCD spectra also showed that the SPM liposomes, which represent the main component of nerve cell membrane, were significantly more disturbed by the presence of BR than the DMPC liposomes-a stable association with a strong VCD signal was observed providing the explanations for the supposed BR neurotoxicity. The effect of time and pH on the BR/DMPC or SPM liposome systems was shown to be essential while the effect of temperature in the range of 15-70°C was negligible demonstrating the surprisingly high temperature stability of BR when interacting with the studied membranes. The influence of a membrane protein was tested on a model consisting of poly-l-arginine (PLAG) bound in the α-helical form to the surface of 1,2-dimyristoyl-sn-glycero-3-phospho-(1'-rac-glycerol) liposomes and sodium dodecyl sulfate micelles. VCD and also ECD spectra showed that a variety of BR diastereoisomers interacted with PLAG in such systems. In a system of PLAG with micelles composed of sodium dodecyl sulfate, the M-form of bound BR was observed. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Bilirubin adsorption properties of water-soluble adsorbents with different cyclodextrin cavities in plasma dialysis system.

    PubMed

    Wang, Zhi; Cao, Yaming; Wei, Houliang; Jia, Lingyun; Xu, Li; Xie, Jian

    2012-02-01

    In this study, we explored the use of α-, β- or γ-cyclodextrin (CD)-grafted polyethyleneimine (PEI) as water-soluble adsorbent for removing excess plasma bilirubin. To evaluate the bilirubin-binding capacity of these adsorbents, bovine serum albumin (BSA) solution or plasma with high level of bilirubin were dialyzed against CD-PEI-spiked dialysate. In BSA solution with an initial biliurbin concentration of 171.5mg/L, α-CD-PEI, β-CD-PEI and γ-CD-PEI achieved adsorption capacities of 2.5, 5.8 and 3.8 mg/g, respectively. In a plasma dialysis system, 45.6% of bilirubin (260 mg/L) was removed from 200 mL plasma by 1L dialysate spiked with 10mg/mL β-CD-PEI, which was significantly higher than that removed by the same volume of BSA-spiked dialysate (P<0.05), demonstrating the strong bilirubin-binding ability of β-CD-PEI. The key feature of bilirubin adsorption was related to the CD functional group, not the PEI matrix. Subsequent molecular docking study indicated that the size of CD cavity could affect the affinity energy of CD-bilirubin complex. The cavity of β-CD was most suitable for accommodating the pyrrole rings of bilirubin. The inclusion complex of bilirubin and β-CD in the molar ratio of 1:2 was more logical in terms of affinity energy. All the results demonstrated the potential of β-CD-PEI (water-soluble adsorbent) as an effective agent for removing of bilirubin from plasma in dialysis system. Copyright © 2011 Elsevier B.V. All rights reserved.

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

    PubMed

    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 < 0.001) and the secondary outcome (adjusted HR 0.20, 95% CI 0.05 to 0.71, P = 0.01) than that of the control group. Moreover, the bilirubin-treated mice showed less fibrosis in the unilateral ureteral obstruction (UUO) model (P < 0.05). In addition, bilirubin treatment decreased fibronectin expression in tubular epithelial cells in a dose-dependent manner (P < 0.05). Mildly elevated serum 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.

  12. Bilirubin treatment suppresses pulmonary inflammation in a rat model of smoke-induced emphysema.

    PubMed

    Wei, Jingjing; Zhao, Hui; Fan, Guoquan; Li, Jianqiang

    2015-09-18

    Cigarette smoking is a significant risk factor for emphysema, which is characterized by airway inflammation and oxidative damage. To assess the capacity of bilirubin to protect against smoke-induced emphysema. Smoking status and bilirubin levels were recorded in 58 patients with chronic obstructive pulmonary diseases (COPD) and 71 non-COPD participants. The impact of smoking on serum bilirubin levels and exogenous bilirubin (20 mg/kg/day) on pulmonary injury was assessed in a rat model of smoking-induced emphysema. At sacrifice lung histology, airway leukocyte accumulation and cytokine and chemokine levels in serum, bronchoalveolar lavage fluid (BALF) and lung were analyzed. Oxidative lipid damage and anti-oxidative components was assessed by measuring malondialdehyde, superoxide dismutase (SOD) activity and glutathione. Total serum bilirubin levels were lower in smokers with or without COPD than non-smoking patients without COPD (P < 0.05). Indirect serum bilirubin levels were lower in COPD patients than patients without COPD (P < 0.05). In rats, cigarette smoke reduced serum total and indirect bilirubin levels. Administration of bilirubin reduced mean linear intercept and mean alveoli area, increased mean alveoli number, reduced macrophage, neutrophil and TNF-α content of BALF, and increased BALF and serum IL-10 level, but lowered local and systemic CCL2, CXCL2, CXCL8 and IL-17 levels. Bilirubin suppressed the smoke-induced systemic and regional oxidative lipid damage associated with increased SOD activity. Bilirubin attenuated smoking-induced pulmonary injury by suppressing inflammatory cell recruitment and pro-inflammatory cytokine secretion, increasing anti-inflammatory cytokine levels, and anti-oxidant SOD activity in a rat model of smoke-induced emphysema. Copyright © 2015. Published by Elsevier Inc.

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

    PubMed Central

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

    2017-01-01

    Background 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. Methods 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. Results 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 < 0.001) and the secondary outcome (adjusted HR 0.20, 95% CI 0.05 to 0.71, P = 0.01) than that of the control group. Moreover, the bilirubin-treated mice showed less fibrosis in the unilateral ureteral obstruction (UUO) model (P < 0.05). In addition, bilirubin treatment decreased fibronectin expression in tubular epithelial cells in a dose-dependent manner (P < 0.05). Conclusions Mildly elevated serum 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. PMID:28225832

  14. Effects of total bilirubin on the prevalence of osteoporosis in postmenopausal women without potential liver disease.

    PubMed

    Bian, Lu-Qin; Li, Rong-Zhen; Zhang, Zheng-Yun; Jin, Yan-Ji; Kang, Hyung-Wook; Fang, Zhen-Zhu; Park, Youn-Soo; Choi, Yoon-Ho

    2013-11-01

    It is still uncertain whether total bilirubin per se is a risk factor for osteoporosis in postmenopausal women and no study has so far examined this important issue. This study was designed to assess the sheer effects of total bilirubin on the prevalence of osteoporosis in postmenopausal women without potential liver disease. In the present study, postmenopausal female subjects without potential liver disease (n = 918) who underwent measurement of bone mineral density were enrolled. Correlation and logistic regression analysis were used to assess the relationship between total bilirubin and other variables. As a result, subjects with osteoporosis had a significantly lower total bilirubin level (P = 0.005). A 0.1 mg/dl increase in total bilirubin was associated with reduced odds ratio of the risk by 38 % for osteoporosis [OR 0.62 (95 % CI 0.52-0.88), P = 0.012] after adjustment for several variables. Total bilirubin was independently associated with BMD [coefficient = 0.41, 95 % CI (0.35-0.47), P < 0.001 for lumbar spine and coefficient = 0.44, 95 % CI (0.36-0.48), P < 0.001 for femur neck]. A positive correlation could be observed with significant difference between total bilirubin and z-score (r = 0.33, P < 0.001 for lumbar spine and r = 0.37, P < 0.001 for femur neck) and total bilirubin was positively correlated with serum calcium (r = 0.13, P < 0.001) as well. Therefore, this study demonstrates an independent inverse association between total bilirubin and the prevalence of osteoporosis in postmenopausal women without potential liver disease. Total bilirubin would be useful as a provisional new risk factor of osteoporosis in such a population.

  15. Inverse Association between Serum Bilirubin Levels and Retinopathy in Patients with Type 2 Diabetes Mellitus

    PubMed Central

    Venkatesan, Raghuram; Thankappan, Lekha; Andavar, Raghuram; Devisundaram, Sundar

    2017-01-01

    Introduction Oxidative stress plays a central role in the pathogenesis of Diabetic Retinopathy (DR) and serum bilirubin has been shown to have antioxidant properties. Aim To investigate the association between serum bilirubin concentration and DR in patients with Type 2 Diabetes Mellitus (DM). Materials and Methods This was a hospital based, cross- sectional study where in 86 patients with Type 2 DM and 30 controls were recruited. The study was conducted at a tertiary care centre in Southern India between January 2014 and December 2014. The presence and the severity of DR were determined by fundus examination and grading of colour fundus photographs using the international clinical disease severity scale for DR. Serum total, direct and indirect bilirubin levels were determined in all subjects and the association between bilirubin levels and severity of DR was studied. Results Among the 86 diabetics, 24 had no retinopathy and 62 had DR of varying grades. The mean total bilirubin level among diabetic subjects (0.52±0.17) and controls (0.51±0.19) were found to be similar. The mean total as well as direct bilirubin levels were found to be lower in patients with retinopathy as compared to no retinopathy group (p<0.001). The severity of DR was inversely proportional to the serum bilirubin levels (p=0.010). Serum total bilirubin was found to have a negative association with glycosylated haemoglobin and served as an independent determinant of DR even after adjusting for risk factors known to be associated with DR (p=0.001). Conclusion Low serum bilirubin levels are significantly associated with increased risk of DR independent of classic risk factors. Serum bilirubin can serve as a useful biomarker in identifying patients at risk for developing proliferative DR. PMID:28384901

  16. Inverse association of serum bilirubin with metabolic syndrome and insulin resistance in Polish population.

    PubMed

    Guzek, Marek; Jakubowski, Zenon; Bandosz, Piotr; Wyrzykowski, Bogdan; Smoczyński, Marian; Jabloiska, Anna; Zdrojewski, Tomasz

    2012-01-01

    Bilirubin has got a potential anti-oxidant, anti-inflammatory and cytoprotective effect. It has been shown that its concentration is inversely related to cardiometabolic diseases. Recent studies have revealed the association between serum bilirubin concentrations and metabolic syndrome (MS) among children and adolescents in U.S. and among Korean adults. The aim of this study was to evaluate the association of total serum bilirubin level with MS and insulin resistance in Poland. We examined 1568 patients aged 18 to 93 years. The tested population was a nationally representative sample of Polish adults. They were derived from cross-sectional study, when serum total bilirubin level and risk factors of cardiovascular diseases were determined. The prevalence of MS in bilirubin level quartiles (95% CI in parentheses) was 28.9% (24.5%-33.3%), 32.6% (28.3%-36.9%), 23.4% (19.0%-27.8%), 21.8% (17.5%-26.2%) respectively for quartiles 1-4 (p = 0.002) The multivariate analysis showed odds ratio for MS in third and fourth quartile of bilirubin level equal to 0.70 (0.50-0.99) and 0.68 (0.48-0.95) respectively in comparison to the lowest quartile. The more criteria of metabolic syndrome were fulfilled by the patient, the lower was mean total bilirubin level (p = 0.012). In study group there was also a strong, independent association of bilirubin level with fasting insulin level and insulin resistance (HOMA-IR). The odds ratio of insulin resistance was 0.53 (0.38-0.74) for the fourth quartile in reference to the lowest quartile of bilirubin. In Polish adults serum total bilirubin level is inversely related to the prevalence of MS and insulin resistance.

  17. Molecular and Biochemical Characterization of a Cytokinin Oxidase from Maize1

    PubMed Central

    Bilyeu, Kristin D.; Cole, Jean L.; Laskey, James G.; Riekhof, Wayne R.; Esparza, Thomas J.; Kramer, Michelle D.; Morris, Roy O.

    2001-01-01

    It is generally accepted that cytokinin oxidases, which oxidatively remove cytokinin side chains to produce adenine and the corresponding isopentenyl aldehyde, play a major role in regulating cytokinin levels in planta. Partially purified fractions of cytokinin oxidase from various species have been studied for many years, but have yet to clearly reveal the properties of the enzyme or to define its biological significance. Details of the genomic organization of the recently isolated maize (Zea mays) cytokinin oxidase gene (ckx1) and some of its Arabidopsis homologs are now presented. Expression of an intronless ckx1 in Pichia pastoris allowed production of large amounts of recombinant cytokinin oxidase and facilitated detailed kinetic and cofactor analysis and comparison with the native enzyme. The enzyme is a flavoprotein containing covalently bound flavin adenine dinucleotide, but no detectable heavy metals. Expression of the oxidase in maize tissues is described. PMID:11154345

  18. Extreme bilirubin levels as a causal risk factor for symptomatic gallstone disease.

    PubMed

    Stender, Stefan; Frikke-Schmidt, Ruth; Nordestgaard, Børge G; Tybjærg-Hansen, Anne

    2013-07-08

    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. To test the hypothesis that a lifelong increase in plasma bilirubin levels is a causal risk factor for symptomatic gallstone disease in the general population. In a prospective study of the Danish general population (N = 61,212), we first tested whether elevated levels of plasma bilirubin predicted greater risk of symptomatic gallstone disease. Second, taking advantage of mendelian randomization, we tested whether a genetic variant in the bilirubin glucoronidating enzyme UGT1A1 (rs6742078) was associated with increased plasma bilirubin levels and, in turn, with an increased risk of symptomatic gallstone disease. Plasma bilirubin level and symptomatic gallstone disease. During 34 years of follow-up, 3374 individuals developed symptomatic gallstone disease. In adjusted analyses, persons with plasma bilirubin levels in the 10th decile had a greater risk of symptomatic gallstone disease compared with those with plasma bilirubin levels in deciles 1 through 9; the hazard ratios (HRs) (95% CIs) were 1.57 (1.26-1.96) overall, 1.36 (1.02-1.82) in women, and 2.00 (1.41-2.83) in men. UGT1A1 genotype explained 20% of the total variation in plasma bilirubin levels and was associated with increases in the mean plasma bilirubin level overall of +16% (+0.09 mg/dL) in GT heterozygotes and +90% (+0.50 mg/dL) in TT homozygotes compared with GG homozygotes, with similar effects in women and men (P for trend <.001 for all). The corresponding HRs (95% CIs) for symptomatic gallstone disease were 1.09 (1.02-1.17) for GT heterozygotes and 1.22 (1.09-1.36) for TT homozygotes vs GG homozygotes and similar in women and men (P for trend = .04-<.001). These results are compatible with a causal association between extreme levels of plasma bilirubin and increased risk of symptomatic gallstone disease.

  19. Influence of Phosphatidylcholine and Calcium on Self-Association and Bile Salt Mixed Micellar Binding of the Natural Bile Pigment, Bilirubin Ditaurate.

    PubMed

    Neubrand, Michael W; Carey, Martin C; Laue, Thomas M

    2015-11-17

    Recently [Neubrand, M. W., et al. (2015) Biochemistry 54, 1542-1557], we determined a concentration-dependent monomer-dimer-tetramer equilibrium in aqueous bilirubin ditaurate (BDT) solutions and explored the nature of high-affinity binding of BDT monomers with monomers and micelles of the common taurine-conjugated bile salts (BS). We now investigate, employing complementary physicochemical methods, including fluorescence emission spectrophotometry and quasi-elastic light scattering spectroscopy, the influence of phosphatidylcholine (PC), the predominant phospholipid of bile and calcium, the major divalent biliary cation, on these self-interactions and heterointeractions. We have used short-chain, lyso and long-chain PC species as models and contrasted our results with those of parallel studies employing unconjugated bilirubin (UCB) as the fully charged dianion. Both bile pigments interacted with the zwitterionic headgroup of short-chain lecithins, forming water-soluble (BDT) and insoluble ion-pair complexes (UCB), respectively. Upon micelle formation, BDT monomers apparently remained at the headgroup mantle of short-chain PCs, but the ion pairs with UCB became internalized within the micelle's hydrophobic core. BDT interacted with the headgroups of unilamellar egg yolk (EY) PC vesicles; however, with the simultaneous addition of CaCl2, a reversible aggregation took place, but not vesicle fusion. With mixed EYPC/BS micelles, BDT became bound to the hydrophilic surface (as with simple BS micelles), and in turn, both BDT and BS bound calcium, but not other divalent cations. The calcium complexation of BDT and BS was enhanced strongly with increases in micellar EYPC, suggesting calcium-mediated cross-bridging of hydrophilic headgroups at the micelle's surface. Therefore, the physicochemical binding of BDT to BS in an artificial bile medium is influenced not only by BS species and concentration but also by long-chain PCs and calcium ions that exert a specific rather

  20. Statins alter the hepatobiliary transport of unconjugated and conjugated bilirubin in sandwich-cultured rat hepatocytes.

    PubMed

    Szabó, Mónika; Veres, Zsuzsa; Bátai-Konczos, Attila; Kékesi, Orsolya; Kis, Emese; Szabó, Kitti; Jemnitz, Katalin

    2014-09-01

    Several studies have reported that statins occasionally cause impairment of liver functions characterized by elevated serum bilirubin levels, which might be due to altered function of the multidrug resistance-associated proteins (Mrp2/3). We aimed to study the modulation of the hepatobiliary transport of bilirubin by four statin derivatives, atorvastatin, fluvastatin, pravastatin, and rosuvastatin in sandwich-cultured rat hepatocytes. All statins except pravastatin significantly inhibited the uptake of bilirubin. The biliary efflux of bilirubin conjugates was increased by pravastatin and rosuvastatin concentration dependently. Rosuvastatin stimulated not only the Mrp2 mediated biliary, but the Mrp3 mediated sinusoidal elimination, resulting in decreased intracellular bilirubin accumulation. The significantly induced Mrp2/3 protein levels (ranging from 1.5 to 1.8-fold) accounted for the elevated efflux. Cell polarization, the formation of biliary network was also significantly increased by fluvastatin, pravastatin and rosuvastatin (151%, 216% and 275% of the control, respectively). The simultaneous inhibition of the uptake and the stimulation of the sinusoidal and canalicular elimination may explain, at least in part, the clinical observation of elevated serum bilirubin levels. In conclusion, our results suggest that in spite of the elevated serum bilirubin levels, the altered Mrp2 and Mrp3 functions by statins is probably not associated with hepatotoxic effects.

  1. Bilirubin conjugates of human bile. Nuclear-magnetic-resonance, infrared and optical spectra of model compounds

    PubMed Central

    Kuenzle, Clive C.

    1970-01-01

    N.m.r., i.r. and optical spectra of model compounds were recorded. These were to help in elucidating the structures of the phenylazo derivatives of bilirubin conjugates isolated from human bile. Model compounds included commercial and human bile bilirubin, mesobilirubin, bilirubin dimethyl ester, dimethoxybilirubin dimethyl ester and the corresponding phenylazo derivatives. The phenylazo derivative of vinylneoxanthobilirubinic acid was also investigated. All compounds were of the type IXα, and no other isomer could be detected with the spectroscopic methods employed. The compounds crystallize as the lactams, except for dimethoxybilirubin dimethyl ester and its phenylazo derivative, which are held in the lactim ether configuration. With all other compounds no tautomeric forms other than the lactams could be detected, although small proportions of bilirubin must exist as the lactim. Bilirubin does not form a betaine, a structure that has been proposed by von Dobeneck & Brunner (1965) to explain the bathochromic shift of its optical spectrum as compared with the expected position of the absorption maximum at 420nm. However, this shift to 453nm can be explained on the basis of internal hydrogen bonds occurring between the carboxylic protons and the pyrrole rings of bilirubin, as proposed by Fog & Jellum (1963), and new evidence for such a bonding has been accumulated. The bilirubin sulphate described by Watson (1958), which is formed by treatment of bilirubin with concentrated sulphuric acid and acetic anhydride, was also investigated. The main product of this reaction was isolated as its phenylazo derivative, and was shown to be 3,18-di(ethylidene sulphate)-2,7,13,17-tetramethylbiladiene-ac-8,12-dipropionic acid. The reaction leading to this compound is an addition of sulphuric acid to the vinyl side chains of bilirubin according to Markownikoff's rule. PMID:5500301

  2. Serum bilirubin levels are inversely associated with nonalcoholic fatty liver disease

    PubMed Central

    Kwak, Min-Sun; Chung, Goh Eun; Kang, Seung Joo; Park, Min Jung; Kim, Yoon Jun; Yoon, Jung-Hwan; Lee, Hyo-Suk

    2012-01-01

    Background/Aims Serum bilirubin exerts antioxidant and cytoprotective effects. In addition, elevated serum bilirubin levels are associated with a decreased risk of metabolic and cardiovascular diseases. However, few studies have evaluated whether serum bilirubin is associated with non-alcoholic fatty liver disease (NAFLD), which is closely associated with other metabolic diseases. The aim of this study was thus to elucidate the association between serum total bilirubin levels and NAFLD. Methods A cross-sectional study of 17,348 subjects undergoing a routine health check-up was conducted. Subjects positive for hepatitis B or hepatitis C virus, or with other hepatitis history were excluded. NAFLD was diagnosed on the basis of typical ultrasonographic findings and an alcohol consumption of less than 20 g/day. Results The mean age of the subjects was 49 years and 9,076 (52.3%) were men. The prevalence of NAFLD decreased steadily as the serum bilirubin level increased in both men and women (P<0.001 for both). Multivariate regression analysis adjusted for other metabolic risk factors showed that serum bilirubin level was inversely associated with the prevalence of NAFLD [odds ratio (OR)=0.88, 95% confidence interval (CI)=0.80-0.97]. Furthermore, there was an inverse, dose-dependent association between NAFLD and serum total bilirubin levels (OR=0.83, 95% CI=0.75-0.93 in the third quartile; OR=0.80, 95% CI=0.71-0.90 in the fourth quartile vs. lowest quartile, P for trend <0.001). Conclusions Serum bilirubin levels were found to be inversely associated with the prevalence of NAFLD independent of known metabolic risk factors. Serum bilirubin might be a protective marker for NAFLD. PMID:23323254

  3. Enterohepatic circulation of nonconjugated bilirubin in rats fed with human milk

    SciTech Connect

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

    1991-03-01

    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.

  4. High preoperative bilirubin values protect against reperfusion injury after live donor liver transplantation.

    PubMed

    Spetzler, Vinzent N; Goldaracena, Nicolas; Kaths, Johann M; Marquez, Max; Selzner, Nazia; Cattral, Mark S; Greig, Paul D; Lilly, Les; McGilvray, Ian D; Levy, Gary A; Ghanekar, Anand; Renner, Eberhard L; Grant, David R; Selzner, Markus

    2015-11-01

    Heme Oxygenase-1 and its product biliverdin/bilirubin have been demonstrated to protect against ischemia/reperfusion injury (IRI). We investigated whether increased preoperative bilirubin values of transplant recipients decrease IRI. Preoperative bilirubin levels of live donor liver recipients were correlated to postoperative liver transaminase as a marker of IRI. Additionally, two recipient groups with pretransplant bilirubin levels >24 μmol/l (n = 348) and ≤24 μmol/l (n = 118) were compared. Post-transplant liver function, complications, length of hospital stay, and patient and graft survival were assessed. Preoperative bilirubin levels were negatively correlated to the postoperative increase in transaminases suggesting a protective effect against IRI. The maximal rise of ALT after transplantation in high versus low bilirubin patients was 288 (-210-2457) U/l vs. 375 (-11-2102) U/l, P = 0.006. Bilirubin remained a significant determining factor in a multivariate linear regression analysis. The MELD score and its individual components as a marker of severity of chronic liver disease were significantly higher in the high versus low bilirubin group (P < 0.001). Despite this, overall complication rate (21.0% vs. 21.2%, P = 0.88), hospital stay [13 (4-260) vs. 14 (6-313) days, P = 0.93), and 1-year graft survival (90.8% vs. 89.0%, P = 0.62) were similar in both groups. High bilirubin levels of liver recipients before live donor transplantation is associated with decreased postoperative IRI.

  5. Relation of Pre-anthracycline Serum Bilirubin Levels to Left Ventricular Ejection Fraction After Chemotherapy.

    PubMed

    Vera, Trinity; D'Agostino, Ralph B; Jordan, Jennifer H; Whitlock, Matthew C; Meléndez, Giselle C; Lamar, Zanetta S; Porosnicu, Mercedes; Bonkovsky, Herbert L; Poole, Leslie B; Hundley, W Gregory

    2015-12-01

    Myocardial injury because of oxidative stress manifesting through reductions in left ventricular ejection fraction (LVEF) may occur after the administration of anthracycline-based chemotherapy (A-bC). We hypothesized that bilirubin, an effective endogenous antioxidant, may attenuate the reduction in LVEF that sometimes occurs after receipt of A-bC. We identified 751 consecutively treated patients with cancer who underwent a pre-A-bC LVEF measurement, exhibited a serum total bilirubin level <2 mg/dl, and then received a post-A-bC LVEF assessment because of symptomatology associated with heart failure. Analysis of variance, Tukey's Studentized range test, and chi-square tests were used to evaluate an association between bilirubin and LVEF changes. The LVEF decreased by 10.7 ± 13.7%, 8.9 ± 11.8%, and 7.7 ± 11.5% in group 1 (bilirubin at baseline ≤0.5 mg/dl), group 2 (bilirubin 0.6 to 0.8 mg/dl), and group 3 (bilirubin 0.9 to 1.9 mg/dl), respectively. More group 1 patients experienced >15% decrease in LVEF compared with those in group 3 (p = 0.039). After adjusting for age, coronary artery disease/myocardial infarction, diabetes mellitus, hematocrit, and the use of cardioactive medications, higher precancer treatment bilirubin levels and lesser total anthracycline doses were associated with LVEF preservation (p = 0.047 and 0.011, respectively). In patients treated with anthracyclines who subsequently develop symptoms associated with heart failure, pre-anthracycline treatment serum bilirubin levels inversely correlate with subsequent deterioration in post-cancer treatment LVEF. In conclusion, these results suggest that increased levels of circulating serum total bilirubin, an intrinsic antioxidant, may facilitate preservation of LVEF in patients receiving A-bC for cancer.

  6. Evaluation of oxidant and antioxidant status in term neonates: a plausible protective role of bilirubin.

    PubMed

    Shekeeb Shahab, M; Kumar, Praveen; Sharma, Neeraj; Narang, Anil; Prasad, Rajendra

    2008-10-01

    In vitro studies have shown unequivocally that bilirubin is an antioxidant. We hypothesized that bilirubin serves a physiological role of an antioxidant in vivo. To investigate the probable protective role of bilirubin in vivo, term babies with clinical jaundice were grouped into four categories-serum total bilirubin (STB) <160 mg/l, 160-200 mg/l, >200 mg/l, and kernicterus. Serum bilirubin, serum albumin, plasma glucose-6-phosphate dehydrogenase (G6PD), lipid peroxidation in blood cells, and reduced glutathione (GSH) content in whole blood were investigated. We also measured superoxide dismutase (SOD) and catalase in hemolysate and total plasma antioxidant capacity (TAC). Lipid peroxidation and antioxidant enzymes were significantly lower in babies with STB <200 mg/l compared to controls. TAC had a positive and MDA had a negative correlation with STB till 200 mg/l. However, TAC had a negative and MDA had a positive correlation with bilirubin >200 mg/l and in babies with bilirubin encephalopathy. Elevated levels of MDA, SOD, and catalase and significantly decreased levels of reduced glutathione and total antioxidant capacity were observed in STB >200 mg/l group. Antioxidant enzymes were also significantly inhibited in bilirubin encephalopathy babies. Post phototherapy, MDA production and antioxidant levels were significantly increased whilst total antioxidant capacity and reduced glutathione were significantly decreased compared to pre-phototherapy values. Exchange transfusion resulted in reduced oxidative stress in subjects with encephalopathy, whereas no significant difference was observed in other babies with STB >200 mg/l. Taken together, the present study propounds that bilirubin acts as a physiological antioxidant till 200 mg/l concentration in full-term normal neonates. It is conjectured that beyond 200 mg/l, it can no longer be considered physiologic. However, the cause of pathological jaundice needs to be identified and treated. The present data documents

  7. [Haemolysis and turbidity influence on three analysis methods of quantitative determination of total and conjugated bilirubin on ADVIA 1650].

    PubMed

    Gobert De Paepe, E; Munteanu, G; Schischmanoff, P O; Porquet, D

    2008-01-01

    Plasma bilirubin testing is crucial to prevent the occurrence of neonatal kernicterus. Haemolysis may occur during sampling and interfere with bilirubin determination. Moreover, lipidic infusions may induce plasma lipemia and also interfere with bilirubin measurement. We evaluated the interference of haemolysis and lipemia with three methods of total and direct bilirubin measurement adaptated on an Advia 1650 analyser (Siemens Medical Solutions Diagnostics) : Synermed (Sofibel), Bilirubin 2 (Siemens) and Bilirubin Auto FS (Diasys). The measurement of total bilirubin was little affected by haemolysis with all three methods. The Bilirubin 2 (Siemens) method was the less sensitive to haemolysis even at low bilirubin levels. The measurement of conjugated bilirubin was significantly altered by low heamoglobin concentrations for Bilirubin Auto FS(R) (30 microM or 0,192 g/100 mL haemoglobin) and for Synermed (60 microM or 0,484 g/100 mL haemoglobin). In marked contrast, we found no haemoglobin interference with the Direct Bilirubin 2 reagent which complied with the method validation criteria from the French Society for Biological Chemistry. The lipemia up to 2 g/L of Ivelip did not affect neither the measurement of total bilirubin for all three methods nor the measurement of conjugated bilirubin with the Diasys and Siemens reagents. However, we observed a strong interference starting at 0,5 g/L of Ivelip with the Synermed reagent. Our data suggest that both Siemens and Diasys methods allow to measure accurately total and conjugated bilirubin in hemolytic and lipemic samples, nevertheless, the Siemens methodology is less affected by these interferences.

  8. NADPH oxidase mediates glucolipotoxicity-induced beta cell dysfunction--clinical implications.

    PubMed

    McCarty, Mark F; Barroso-Aranda, Jorge; Contreras, Francisco

    2010-03-01

    An impairment of glucose-stimulated insulin secretion--reflecting decreased glucokinase expression--and a moderate decrease in beta cell mass attributable to increased apoptosis, constitute the key features of beta cell failure in type 2 diabetes. Oxidative stress, provoked by prolonged exposure to excessive levels of glucose and/or fatty acids (glucolipotoxicity), appears to be a key mediator of these defects. Oxidant-provoked JNK activation induces nuclear export of the PDX-1 transcription factor, required for expression of glucokinase and other beta cell proteins. Conversely, increases in cAMP induced by incretin hormones promote the nuclear importation of PDX-1, counteracting the diabetogenic impact of oxidant stress; this may explain the utility of measures that slow dietary carbohydrate absorption for diabetes prevention. The ability of oxidative stress to boost apoptosis in beta cells is poorly understood, but may also entail JNK activation. Recent work establishes a phagocyte-type NADPH oxidase as the chief source of glucotoxicity-mediated oxidative stress in beta cells. Since bilirubin is now known to function physiologically as an inhibitor of NADPH oxidase, and phycocyanobilin (PCB) derived from spirulina likewise can inhibit this enzyme complex, supplemental PCB may have utility in the prevention and control of diabetes, and Gilbert syndrome, associated with chronically elevated free bilirubin, may be associated with decreased diabetes risk. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  9. Unconjugated bilirubin effect on 3H-ouabain binding to human fetal red cells.

    PubMed

    Corchs, J L; Corchs, M J; Serrani, R E

    1994-03-01

    Human fetal red cells show heterogeneity of 3H-ouabain binding sites. These cells were chosen as a model to look into unconjugated bilirubin effects on the primary active Na(+)-K+ transport mechanism. Evidences are presented suggesting that unconjugated bilirubin affects 3H-ouabain binding but not through a direct effect. This is supported by the fact that the "low affinity" subgroup sites of the last mentioned ligand persists after unconjugated bilirubin treatment of cells, whereas the "high-affinity" subgroup disappears.

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Isolation of ubiquinol oxidase from Paracoccus denitrificans and resolution into cytochrome bc1 and cytochrome c-aa3 complexes.

    PubMed

    Berry, E A; Trumpower, B L

    1985-02-25

    An enzyme complex with ubiquinol-cytochrome c oxidoreductase, cytochrome c oxidase, and ubiquinol oxidase activities was purified from a detergent extract of the plasma membrane of aerobically grown Paracoccus denitrificans. This ubiquinol oxidase consists of seven polypeptides and contains two b cytochromes, cytochrome c1, cytochrome aa3, and a previously unreported c-type cytochrome. This c-type cytochrome has an apparent Mr of 22,000 and an alpha absorption maximum at 552 nm. Retention of this c cytochrome through purification presumably accounts for the independence of ubiquinol oxidase activity on added cytochrome c. Ubiquinol oxidase can be separated into a 3-subunit bc1 complex, a 3-subunit c-aa3 complex, and a 57-kDa polypeptide. This, together with detection of covalently bound heme and published molecular weights of cytochrome c1 and the subunits of cytochrome c oxidase, allows tentative identification of most of the subunits of ubiquinol oxidase with the prosthetic groups present. Ubiquinol oxidase contains cytochromes corresponding to those of the mitochondrial bc1 complex, cytochrome c oxidase complex, and a bound cytochrome c. Ubiquinol-cytochrome c oxidoreductase activity of the complex is inhibited by inhibitors of the mitochondrial bc1 complex. Thus it seems likely that the pathway of electron transfer through the bc1 complex of ubiquinol oxidase is similar to that through the mitochondrial bc1 complex. The number of polypeptides present is less than half the number in the corresponding mitochondrial complexes. This structural simplicity may make ubiquinol oxidase from P. denitrificans a useful system with which to study the mechanisms of electron transfer and energy transduction in the bc1 and cytochrome c oxidase sections of the respiratory chain.

  12. Lysyl oxidase in colorectal cancer.

    PubMed

    Cox, Thomas R; Erler, Janine T

    2013-11-15

    Colorectal cancer is the third most prevalent form of cancer worldwide and fourth-leading cause of cancer-related mortality, leading to ~600,000 deaths annually, predominantly affecting the developed world. Lysyl oxidase is a secreted, extracellular matrix-modifying enzyme previously suggested to act as a tumor suppressor in colorectal cancer. However, emerging evidence has rapidly implicated lysyl oxidase in promoting metastasis of solid tumors and in particular colorectal cancer at multiple stages, affecting tumor cell proliferation, invasion, and angiogenesis. This emerging research has stimulated significant interest in lysyl oxidase as a strong candidate for developing and deploying inhibitors as functional efficacious cancer therapeutics. In this review, we discuss the rapidly expanding body of knowledge concerning lysyl oxidase in solid tumor progression, highlighting recent advancements in the field of colorectal cancer.

  13. Physical measurements of Cu{sup 2+}-complexes of bilirubin

    SciTech Connect

    Ferraro, J.R.; Wu, J.G.; Li, W.H.; Xu, Y.Z.; Xu, D.F.; Shen, G.R.; Soloway, R.D.

    1995-12-31

    Copper is known to form complexes with bilirubin (H{sub 2}BR). Such complexes have received increased attention due to their clinical significance as free-radical scavengers. The purpose of this study was to examine a series of Cu{sup 2+}BR complexes to ascertain the nature of the binding between Cu{sup 2+} and BR. Several physical measurements of the salts were made, such as Fourier Transform Infrared (FT-IR), Fourier Transform Raman spectroscopy (FT-R), and Electron Paramagnetic Resonance (EPR). The complexes were prepared by dissolving protonated BR in NaOH, and adding different ratios of aqueous CuCl{sub 2}. At ratios of Cu{sup 2+}:H{sub 2}BR of 1:1 and 2:1, soluble complexes were formed. In solution EPR spectra demonstrated 9 hyperfine peaks, which from the splitting, is indicative of Cu{sup 2+} coordinated to 4 nitrogen atoms coming from 2 molecules of BR.

  14. Highly Sensitive and Selective Sensing of Free Bilirubin Using Metal-Organic Frameworks-Based Energy Transfer Process.

    PubMed

    Du, Yaran; Li, Xiqian; Lv, Xueju; Jia, Qiong

    2017-09-13

    Free bilirubin, a key biomarker for jaundice, was detected with a newly designed fluorescent postsynthetically modified metal organic framework (MOF) (UIO-66-PSM) sensor. UiO-66-PSM was prepared based on the aldimine condensation reaction of UiO-66-NH2 with 2,3,4-trihydroxybenzaldehyde. The fluorescence of UIO-66-PSM could be effectively quenched by free bilirubin via a fluorescent resonant energy transfer process, thus achieving its recognition of free bilirubin. It was the first attempt to design a MOF-based fluorescent probe for sensing free bilirubin. The probe exhibited fast response time, low detection limit, wide linear range, and high selectivity toward free bilirubin. The sensing system enabled the monitor of free bilirubin in real human serum. Hence, the reported free bilirubin sensing platform has potential applications for clinical diagnosis of jaundice.

  15. In vitro and in vivo studies on adlay-derived seed extracts: phenolic profiles, antioxidant activities, serum uric acid suppression, and xanthine oxidase inhibitory effects.

    PubMed

    Zhao, Mouming; Zhu, Dashuai; Sun-Waterhouse, Dongxiao; Su, Guowan; Lin, Lianzhu; Wang, Xiao; Dong, Yi

    2014-08-06

    This study aimed to explore the potential of polished adlay, brown adlay, adlay bran, and adlay hull to prevent and treat hyperuricemia. Brown adlay extract effectively decreased the serum uric acid levels of oxonate-induced hyperuricemic rats. Free and bound phenolic extracts from these materials contained significant amounts of phenolics, with free phenolics dominated by chlorogenic acid and p-coumaric acid while bound phenolics dominated by p-coumaric acid and ferulic acid. Free and bound phenolics of adlay bran exhibited significant xanthine oxidase inhibition activities, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities, oxygen radical absorbance capacities, and superoxide radical scavenging activities. Adlay bran phenolics could be effective xanthine oxidase inhibitors and radical scavengers. p-Coumaric acid is a xanthine oxidase inhibitor with strong superoxide radical scavenging activity. However, ferulic acid is a xanthine oxidase inhibitor with weak superoxide radical scavenging activity. Chlorogenic acid is a superoxide radical scavenger with weak xanthine oxidase inhibitory activity.

  16. Respiratory burst oxidase of fertilization.

    PubMed Central

    Heinecke, J W; Shapiro, B M

    1989-01-01

    Partially reduced oxygen species are toxic, yet sea urchin eggs synthesize H2O2 in a "respiratory burst" at fertilization, as an extracellular oxidant to crosslink their protective surface envelopes. To study the biochemical mechanism for H2O2 production, we have isolated an NADPH-specific oxidase fraction from homogenates of unfertilized Strongylocentrotus purpuratus eggs that produces H2O2 when stimulated with Ca2+ and MgATP2-. Concentrations of free Ca2+ previously implicated in regulation of egg activation modulate the activity of the oxidase. Inhibitors were used to test the relevance of this oxidase to the respiratory burst of fertilization. Procaine, two phenothiazines, and N-ethylmaleimide (but not iodoacetamide) inhibited H2O2 production by the oxidase fraction and oxygen consumption by activated eggs. The ATP requirement suggested that protein kinase activity might regulate the respiratory burst of fertilization; consonant with this hypothesis, H-7 and staurosporine were inhibitory. The respiratory burst oxidase of fertilization is an NADPH:O2 oxidoreductase that appears to be regulated by a protein kinase; although it bears a remarkable resemblance to the neutrophil oxidase, unlike the latter it does not form O2- as its initial product. PMID:2537493

  17. Levels and interactions of plasma xanthine oxidase, catalase and liver function parameters in Nigerian children with Plasmodium falciparum infection.

    PubMed

    Iwalokun, B A; Bamiro, S B; Ogunledun, A

    2006-12-01

    Elevated plasma levels of xanthine oxidase and liver function parameters have been associated with inflammatory events in several human diseases. While xanthine oxidase provides in vitro protection against malaria, its pathophysiological functions in vivo and interactions with liver function parameters remain unclear. This study examined the interactions and plasma levels of xanthine oxidase (XO) and uric acid (UA), catalase (CAT) and liver function parameters GOT, GPT and bilirubin in asymptomatic (n=20), uncomplicated (n=32), and severe (n=18) falciparum malaria children aged 3-13 years. Compared to age-matched control (n=16), significant (p<0.05) elevation in xanthine oxidase by 100-550%, uric acid by 15.4-153.8%, GOT and GPT by 22.1-102.2%, and total bilirubin by 2.3-86% according to parasitaemia (geometric mean parasite density (GMPD)=850-87100 parasites/microL) was observed in the malarial children. Further comparison with control revealed higher CAT level (16.2+/-0.5 vs 14.6+/-0.4 U/L; p<0.05) lacking significant (p>0.05) correlation with XO, but lower CAT level (13.4-5.4 U/L) with improved correlations (r=-0.53 to -0.91; p<0.05) with XO among the asymptomatic and symptomatic malaria children studied. 75% of control, 45% of asymptomatic, 21.9% of uncomplicated, and none of severe malaria children had Hb level>11.0 g/dL. Multivariate analyses further revealed significant (p<0.05) correlations between liver function parameters and xanthine oxidase (r=0.57-0.64) only in the severe malaria group. We conclude that elevated levels of XO and liver enzymes are biochemical features of Plasmodium falciparum parasitaemia in Nigerian children, with both parameters interacting differently to modulate the catalase response in asymptomatic and symptomatic falciparum malaria.

  18. A comparison between transcutaneous and total serum bilirubin in healthy-term greek neonates with clinical jaundice.

    PubMed

    Neocleous, Charalambos; Adramerina, Alkistis; Limnaios, Stefanos; Symeonidis, Symeon; Spanou, Chrysoula; Malakozi, Marina; Mpampalis, Evangelos

    2014-01-01

    The accuracy of transcutaneous bilirubin meters has been assessed in newborns from various ethnic backgrounds. However, there are limited data on Greek newborns. Our study examined the accuracy of transcutaneous bilirubin measurements in clinically jaundiced healthy-term Greek newborns, using total serum bilirubin as the reference standard, in order to re-evaluate our local guidelines about neonatal jaundice. Clinically jaundiced newborns requiring total serum bilirubin level estimation were recruited prospectively. 368 pairs of total serum bilirubin/transcutaneous bilirubin measurements were taken in 222 newborns, using a direct spectrophotometric device and the BiliCheck device, respectively. The level of agreement between the obtained transcutaneous bilirubin and total serum bilirubin values was assessed. Our data were analysed using the Stata/SE 12.0 (StataCorp LP, USA) statistical programme. The mean (± SD) TSB was 225.4 ± 25.4 μmol/l and the mean (± SD) TcB was 237.9 ± 21.0 μmol/l. The correlation between the values was poor (Pearson's correlation coefficient 0.439; Lin's concordance coefficient 0.377 [95% CI 0.301 to 0.453]; P<0.001). The Bland-Altman analysis demonstrated that transcutaneous bilirubin measurements tended to overestimate the total serum bilirubin value (mean difference 12.5 ± 24.9 μmol/l), with wide 95% limits of agreement (-36.2 μmol/l to 61.3 μmol/l). Transcutaneous bilirubin values did not correlate well with total serum bilirubin values, being often imprecise in predicting the actual total serum bilirubin levels. This permits us to continue estimating total serum bilirubin in clinically jaundiced newborns according to our local guidelines, in order to safely decide the appropriate care plan.

  19. 21 CFR 862.1113 - Bilirubin (total and unbound) in the neonate test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1113 Bilirubin (total and unbound) in the neonate test system. (a...

  20. 21 CFR 862.1113 - Bilirubin (total and unbound) in the neonate test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1113 Bilirubin (total and unbound) in the neonate test system. (a...

  1. 21 CFR 862.1113 - Bilirubin (total and unbound) in the neonate test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1113 Bilirubin (total and unbound) in the neonate test system. (a...

  2. 21 CFR 862.1113 - Bilirubin (total and unbound) in the neonate test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1113 Bilirubin (total and unbound) in the neonate test system. (a...

  3. The effect of bilirubin on lipid peroxidation and antioxidant enzymes in cumene hydroperoxide-treated erythrocytes.

    PubMed

    Yeşilkaya, A; Yeğin, A; Ozdem, S; Aksu, T A

    1998-01-01

    Recently, it has been suggested that bilirubin may act as a potent biological chain-breaking antioxidant. To observe the effects of free bilirubin on antioxidant reactions in cumene hydroperoxide-treated erythrocytes (15 g hemoglobin/dl), we added bilirubin at four different concentrations (0.5, 1, 5, and 10 mg/dl). We measured the thiobarbituric acid-reactive substance and reduced glutathione levels, and some antioxidant enzyme activities, namely superoxide dismutase, catalase, and glucose-6-phosphate dehydrogenase. Thiobarbituric acid-reactive substance and chemiluminescent signals decreased during the incubation. Superoxide dismutase activities also decreased but not as much as in the control group. Glucose-6-phosphate dehydrogenase activities and reduced glutathione levels increased, but catalase activities remained the same as the control group. Our results suggest that bilirubin--in the concentrations we have used--partially prevented the oxidant effects of cumene hydroperoxide.

  4. Computational chemical analysis of unconjugated bilirubin anions and insights into pKa values clarification

    NASA Astrophysics Data System (ADS)

    Vega-Hissi, Esteban G.; Estrada, Mario R.; Lavecchia, Martín J.; Pis Diez, Reinaldo

    2013-01-01

    The pKa, the negative logarithm of the acid dissociation equilibrium constant, of the carboxylic acid groups of unconjugated bilirubin in water is a discussed issue because there are quite different experimental values reported. Using quantum mechanical calculations we have studied the conformational behavior of unconjugated bilirubin species (in gas phase and in solution modeled implicitly and explicitly) to provide evidence that may clarify pKa values because of its pathophysiological relevance. Our results show that rotation of carboxylate group, which is not restricted, settles it in a suitable place to establish stronger interactions that stabilizes the monoanion and the dianion to be properly solvated, demonstrating that the rationalization used to justify the high pKa values of unconjugated bilirubin is inappropriate. Furthermore, low unconjugated bilirubin (UCB) pKa values were estimated from a linear regression analysis.

  5. Trigonopsis variabilis d-Amino Acid Oxidase: Control of Protein Quality and Opportunities for Biocatalysis through Production in Escherichia coli▿ †

    PubMed Central

    Dib, Iskandar; Stanzer, Damir; Nidetzky, Bernd

    2007-01-01

    Trigonopsis variabilis d-amino acid oxidase accounts for 35% of Escherichia coli protein when added d-methionine suppresses the toxic activity of the recombinant product. Permeabilized E. coli cells are reusable and stabilized enzyme preparations. The purified oxidase lacks the microheterogeneity of the natural enzyme. Oriented immobilization of a chimeric oxidase maintains 80% of the original activity in microparticle-bound enzymes. PMID:17056691

  6. High serum bilirubin is associated with the reduced risk of diabetes mellitus and diabetic nephropathy.

    PubMed

    Han, Seung Seok; Na, Ki Young; Chae, Dong-Wan; Kim, Yon Su; Kim, Suhnggwon; Chin, Ho Jun

    2010-06-01

    Several studies have suggested a potential effect of serum bilirubin as an antioxidant and cytoprotectant factor. For the results presented here, we evaluated the correlation between serum bilirubin and diabetes mellitus (DM) or chronic kidney disease originated from DM (DMCKD) in a Korean population. We used a cross-sectional, population-based design to examine 93,909 subjects (aged 18-96 years, 53.0% male). The trend of P values in the odds ratios for being DM and DMCKD was calculated using patients separated into five groups based on individual serum bilirubin concentrations. The prevalence of DM and DMCKD was 6.7% and 0.8%, respectively. Higher serum bilirubin levels were significantly associated with decreased prevalence of DM in both men (P trend < 0.001) and women (P trend = 0.014). The risk of DMCKD also decreased as bilirubin levels increased in women (P trend = 0.011), but not in men (P trend = 0.467). Serum bilirubin level was inversely related to insulin resistance using the homeostasis model assessment (HOMA-IR), serum insulin, and C-reactive protein (CRP) levels in multiple linear regression analyses. The regression coefficients (B) of log-HOMA-IR, log-insulin, and log-CRP were as follows: -0.09, -0.13, and -0.60 in men; -0.07, -0.09, and -0.50 in women, respectively. All the regressions were statistically significant (P < 0.001). These results indicate that serum bilirubin might have some protective function against DM and DMCKD, although the association between high serum bilirubin and decreased prevalence of DMCKD is observed only in women.

  7. Serum bilirubin levels, UGT1A1 polymorphisms and risk for coronary artery disease.

    PubMed

    Lingenhel, Arno; Kollerits, Barbara; Schwaiger, Johannes P; Hunt, Steven C; Gress, Richard; Hopkins, Paul N; Schoenborn, Veit; Heid, Iris M; Kronenberg, Florian

    2008-12-01

    Low levels of the antioxidative serum bilirubin are associated with vascular aging and an increased risk for coronary artery disease (CAD). UGT1A1 is the major gene influencing bilirubin concentrations. Therefore, we investigated an association of bilirubin levels and two polymorphisms in the promoter of UGT1A1 (-53(TA-repeat) polymorphism and T-3279G) in 477 patients with premature, familial CAD and 619 age- and sex-matched controls. Bilirubin concentrations were significantly lower in cases than in controls (0.62+/-0.36 vs. 0.76+/-0.41 mg/dl for men, p=1.2 x 10(-10); and 0.42+/-0.29 vs. 0.55+/-0.23 mg/dl, p=1.9 x 10(-9) for women). Both polymorphisms showed a strong association with bilirubin levels with higher levels for homozygote carriers of the minor allele. These associations were most pronounced in male controls and patients (p=5.9 x 10(-26) and p=3.4 x 10(-16), respectively, for the -53(TA-repeat) polymorphism). Logistic regression analysis revealed low bilirubin levels but not the UGT1A1 polymorphisms to be significantly associated with CAD: OR (95% CI) 0.90 (0.86-0.94), p=2.6 x 10(-6) for men and 0.77 (0.68-0.87), p=3.2 x 10(-5) for women, respectively for each 0.1mg/dl increase of bilirubin. These results indicate that it is rather decreased bilirubin levels in general than the changes in the genetic variation of this gene that increase the risk for CAD.

  8. Constituents of Bile, Bilirubin and TUDCA, Protect Against Oxidative Stress-Induced Retinal Degeneration

    PubMed Central

    Oveson, Brian C.; Iwase, Takeshi; Hackett, Sean F.; Lee, Sun Young; Usui, Shinichi; Sedlak, Thomas W.; Snyder, Solomon H.; Campochiaro, Peter A.; Sung, Jennifer U.

    2014-01-01

    Two constituents of bile, bilirubin and tauroursodeoxycholic acid (TUDCA), have antioxidant activity. However, bilirubin can also cause damage to some neurons and glial cells, particularly immature neurons. In this study, we tested the effects of bilirubin and TUDCA in two models in which oxidative stress contributes to photoreceptor cell death, prolonged light exposure and rd10+/+ mice. In albino BALB/c mice, intraperitoneal (IP) injection of 5 mg/kg of bilirubin or 500 mg/kg of TUDCA prior to exposure to 5,000 lux of white light for 8 hours significantly reduced loss of rod and cone function assessed by electroretinograms (ERGs). Both treatments also reduced light-induced accumulation of superoxide radicals in the outer retina, rod cell death assessed by outer nuclear layer (ONL) thickness, and disruption of cone inner and outer segments. In rd10+/+ mice, IP injections of 5 or 50 mg/kg of bilirubin or 500 mg/kg of TUDCA every 3 days starting at postnatal day (P) 6, caused significant preservation of cone cell number and cone function at P50. Rods were not protected at P50, but both bilirubin and TUDCA provided modest preservation of ONL thickness and rod function at P30. These data suggest that correlation of serum bilirubin levels with rate of vision loss in patients with retinitis pigmentosa (RP) could provide a useful strategy to test the hypothesis that cones die from oxidative damage in patients with RP. If proof-of-concept is established, manipulation of bilirubin levels and administration of TUDCA could be tested in interventional trials. PMID:21054389

  9. Elevated serum bilirubin levels are inversely associated with coronary artery atherosclerosis.

    PubMed

    Kang, Seung Joo; Kim, Donghee; Park, Hyo Eun; Chung, Goh Eun; Choi, Seung Ho; Choi, Su-Yeon; Lee, Whal; Kim, Joo Sung; Cho, Sang-Heon

    2013-10-01

    Inverse correlations of high serum bilirubin with metabolic and cardiovascular disease have been suggested. However, anti-atherogenic effects of bilirubin have not been well-established in terms of the presence of plaques and stenosis identified in coronary computed tomography (CT). A cross-sectional study was conducted on 2862 men who were free of cardiovascular disease and underwent coronary CT as part of a routine medical screening examination. Coronary stenotic lesions were considered to be incidences of coronary atherosclerosis, and stenosis was classified as stenosis <50% or ≥50%, according to degree of stenosis. The prevalences of coronary atherosclerosis and stenosis ≥50% in subjects with elevated bilirubin levels (>1.2 mg/dL) were lower than those in subjects with normal bilirubin levels (≤1.2 mg/dL) (19.9% vs. 27.9%, p < 0.001, 8.5% vs. 10.3%, p = 0.044). Bilirubin was inversely associated with total plaques (odds ratio [OR] 0.59, 95% confidence interval [CI] 0.48-0.73 in the 4th quartile vs. 1st quartile) and calcified plaques (OR 0.60, 95% CI 0.49-0.75) in univariate analysis. After adjusting for traditional risk factors, it was found that coronary atherosclerosis (OR 0.73, 95% CI 0.56-0.94 in the 4th quartile vs. 1st quartile) and calcified plaque (OR 0.66, 95% CI 0.53-0.84) were inversely associated with the bilirubin grade in a dose-dependent manner. The serum bilirubin level was inversely associated with coronary atherosclerosis and calcified plaques in a dose-dependent manner. These results suggested that serum bilirubin could be used as a protective biomarker of coronary artery disease. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  10. The effect of delayed transportation of blood samples on serum bilirubin values in neonates.

    PubMed

    Saththasivam, Poovendran; Voralu, Kirtanaa; Ramli, Noraida; Mustapha, Mohd Rafi; Omar, Julia; Van Rostenberghe, Hans

    2010-07-01

    Delays in transporting blood samples may cause inaccurate results. Samples may be exposed to light or heat during delays, resulting in the degradation of analytes, for example, bilirubin. This study was done to determine the effect of delays in the transportation of blood samples on serum bilirubin test results. Samples taken from neonates admitted to a tertiary hospital with jaundice were included in the study. The samples were collected through venipuncture in 3 labelled containers. The first container was sent immediately to the laboratory, while the second and third containers were sent after being kept in the ward for 1 and 3 hours, respectively. Bilirubin values were measured colourimetrically at a wavelength of 578 nm using a Roche Hitachi 912 Chemistry Analyser upon arrival in the laboratory. A total of 36 serum samples were studied. The mean of the indirect bilirubin measurements for 0-, 1-, and 3-hour samples were 174 (SD 68.65), 186.97 (SD 60.47), and 184.56 (SD 66.93), respectively. There was a significant difference in the mean indirect bilirubin measurement of 1-hour samples (P = 0.047, 95% CI -24.66 to -1.18) and 3-hour samples (P = 0.045, 95% CI -19.77 to -0.23) compared with 0-hour samples. There were no significant differences observed in either the mean total bilirubin or the mean direct bilirubin measurements of different time intervals. This study confirms that delays in the transportation of blood samples influence the bilirubin test results.

  11. Association of serum bilirubin with oxidant damage of human atherosclerotic plaques and the severity of atherosclerosis.

    PubMed

    Lapenna, Domenico; Ciofani, Giuliano; Pierdomenico, Sante Donato; Giamberardino, Maria Adele; Ucchino, Sante; Davì, Giovanni

    2017-09-25

    Bilirubin has protective effects against atherosclerotic cardiovascular diseases hypothetically due to its antioxidant-antilipoperoxidative properties. Thus, we investigated whether serum bilirubin is associated with oxidant damage, namely lipid peroxidation, of human atherosclerotic plaques and the severity of atherosclerosis. In this regard, we correlated the levels of serum total bilirubin (STB), direct (conjugated) bilirubin (SDB) and indirect (unconjugated) bilirubin (SIB) with those of fluorescent damage products of lipid peroxidation (FDPL) and lipid hydroperoxides (LOOH) of 32 endarterectomy-derived carotid atherosclerotic plaques. Moreover, we compared the levels of serum bilirubin and plaque lipoperoxides between two groups of patients of the study population with different severity of atherosclerosis as judged by the carotid stenosis degree, i.e., <90% (group A, n = 23) and ≥90% (group B, n = 9). Remarkably, the levels of STB were strongly inversely correlated with those of plaque FDPL (rS = -0.70, P < 0.0001) and LOOH (rS = -0.66, P < 0.0001), as were those of SIB (FDPL: rS = -0.68, P < 0.0001; LOOH: rS = -0.63, P < 0.0001). SDB had a weaker association with plaque FDPL (rS = -0.41, P < 0.05) and LOOH (rS = -0.35, P < 0.05). Moreover, the levels of STB, SDB and SIB were lower and those of plaque lipoperoxides higher in group B than in group A, pointing to the association of serum bilirubin and plaque oxidant burden with the severity of atherosclerosis. In conclusion, lowered serum bilirubin is associated with oxidant damage of human atherosclerotic plaques and the severity of atherosclerosis.

  12. The utility of inpatient rebound bilirubin levels in infants readmitted after birth hospitalization for hyperbilirubinemia.

    PubMed

    Berkwitt, Adam; Osborn, Rachel; Grossman, Matthew

    2015-02-01

    There are few data evaluating the role of inpatient rebound bilirubin levels in the management of infants readmitted after their birth hospitalization for indirect hyperbilirubinemia. The goal of the present study was to evaluate the clinical utility of inpatient rebound bilirubin levels within this patient population. A retrospective cohort study was conducted of 226 infants readmitted after their birth hospitalization for indirect hyperbilirubinemia. Data from 130 infants with rebound bilirubin levels drawn at a mean of 6.1±2.4 hours after discontinuation of phototherapy were compared with data from 96 infants without rebound bilirubin levels. The primary outcome was readmission to the hospital, and secondary outcomes included length of stay and discharge time. A subgroup analysis compared characteristics of children who required repeat phototherapy versus those who did not. Overall, 5 of 130 patients from the rebound group were readmitted compared with 4 of 96 patients from the no-rebound group (P=.98). Length of stay was significantly longer for patients with rebound bilirubin levels (27.7 vs 23.2 hours; P=.001). Patients with bilirubin levels lowered to ≤14 mg/dL were less likely to receive repeat phototherapy than those with levels>14 mg/dL (2 of 129 vs 12 of 97; P=.001). Early inpatient rebound bilirubin levels do not successfully predict which patients will require hospital readmission for repeat phototherapy. Children with bilirubin levels lowered to ≤14 mg/dL with phototherapy are unlikely to receive repeat phototherapy. Copyright © 2015 by the American Academy of Pediatrics.

  13. Potential role of conjugated bilirubin and copper in the metabolism of lipid peroxides in bile.

    PubMed Central

    Stocker, R; Ames, B N

    1987-01-01

    Conjugated bilirubin and copper ions at their physiological concentrations in bile may play an important role in hydroperoxide and other detoxification. Conjugated bilirubin may also be an important chain-breaking antioxidant preventing lipid peroxidation. Bilirubin ditaurine (BR-DT), a water-soluble model compound of conjugated bilirubin, completely prevents the peroxyl radical-induced oxidation of phosphatidylcholine in either multilamellar liposomes or micelles. This antioxidant activity is associated with the bilirubin moiety of BR-DT, since taurine alone is inefficient in scavenging peroxyl radicals. The number of peroxyl radicals trapped per molecule of BR-DT is 1.9, compared to 4.7 trapped per molecule of biliverdin, the water-soluble physiological precursor of bilirubin. Peroxyl radical-induced oxidation of BR-DT results in a spectral shift in maximal absorbance toward shorter wavelengths; biliverdin is not formed as a major oxidation product. BR-DT, but neither taurine nor biliverdin, greatly accelerates the cupric ion-catalyzed decomposition of linoleic acid hydroperoxide. In the presence of ferric ion, BR-DT shows no lipid hydroperoxide-degrading activity. Addition of cupric ion to BR-DT results in formation of a complex with spectral features similar to that of a biliverdin-cupric ion complex, indicating that BR-DT and cupric ion undergo redox reactions. PMID:3479781

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

    PubMed Central

    Levitt, David G; Levitt, Michael D

    2014-01-01

    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. PMID:25214800

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

    PubMed

    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.

  16. Successive determination of urinary bilirubin and creatinine employing simultaneous injection effective mixing flow analysis.

    PubMed

    Ponhong, Kraingkrai; Teshima, Norio; Grudpan, Kate; Vichapong, Jitlada; Motomizu, Shoji; Sakai, Tadao

    2015-02-01

    A novel four-channel simultaneous injection effective mixing flow analysis (SIEMA) system has been assembled for successive determination of bilirubin and creatinine in urinary samples. The chemical variables and physical parameters in the flow system were optimized for the enhancement of successive analytical performances. The interferences from urine matrices on the determination of bilirubin and creatinine were eliminated to dilute urine samples. The calibration graphs with the optimum conditions were achieved to be in 0.024-5.0 mg L(-1) for bilirubin and 2-100 mg L(-1) for creatinine. The relative standard deviations (RSDs) at 3 mg L(-1) of bilirubin and at 50 mg L(-1) of creatinine for 11 runs were 1.5 and 1.0%, respectively. The limits of detections (3σ of blank) for bilirubin and creatinine were 7 µg L(-1) and 0.6 mg L(-1), respectively. The sample throughput for stepwise detection was 22 h(-1). The proposed method was applied to the successive determination of bilirubin and creatinine in urine samples.

  17. Bilirubin scavenges chloramines and inhibits myeloperoxidase-induced protein/lipid oxidation in physiologically relevant hyperbilirubinemic serum.

    PubMed

    Boon, A C; Hawkins, C L; Coombes, J S; Wagner, K H; Bulmer, A C

    2015-09-01

    Hypochlorous acid (HOCl), an oxidant produced by myeloperoxidase (MPO), induces protein and lipid oxidation, which is implicated in the pathogenesis of atherosclerosis. Individuals with mildly elevated bilirubin concentrations (i.e., Gilbert syndrome; GS) are protected from atherosclerosis, cardiovascular disease, and related mortality. We aimed to investigate whether exogenous/endogenous unconjugated bilirubin (UCB), at physiological concentrations, can protect proteins/lipids from oxidation induced by reagent and enzymatically generated HOCl. Serum/plasma samples supplemented with exogenous UCB (≤250µM) were assessed for their susceptibility to HOCl and MPO/H2O2/Cl(-) oxidation, by measuring chloramine, protein carbonyl, and malondialdehyde (MDA) formation. Serum/plasma samples from hyperbilirubinemic Gunn rats and humans with GS were also exposed to MPO/H2O2/Cl(-) to: (1) validate in vitro data and (2) determine the relevance of endogenously elevated UCB in preventing protein and lipid oxidation. Exogenous UCB dose-dependently (P<0.05) inhibited HOCl and MPO/H2O2/Cl(-)-induced chloramine formation. Albumin-bound UCB efficiently and specifically (3.9-125µM; P<0.05) scavenged taurine, glycine, and N-α-acetyllysine chloramines. These results were translated into Gunn rat and GS serum/plasma, which showed significantly (P<0.01) reduced chloramine formation after MPO-induced oxidation. Protein carbonyl and MDA formation was also reduced after MPO oxidation in plasma supplemented with UCB (P<0.05; 25 and 50µM, respectively). Significant inhibition of protein and lipid oxidation was demonstrated within the physiological range of UCB, providing a hypothetical link to protection from atherosclerosis in hyperbilirubinemic individuals. These data demonstrate a novel and physiologically relevant mechanism whereby UCB could inhibit protein and lipid modification by quenching chloramines induced by MPO-induced HOCl. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. The number of nucleotide binding sites in cytochrome C oxidase.

    PubMed

    Rieger, T; Napiwotzki, J; Hüther, F J; Kadenbach, B

    1995-12-05

    The binding of 2'(3')-O-(2,4,6-trinitrophenyl)-adenosine-5'-triphosphate (TNP-ATP), [35S]ATP alpha S and 8-azido-[gamma-32P]ATP to isolated cytochrome c oxidase of bovine heart and liver and to the two-subunit enzyme of Paracoccus dentrificans was studied by measuring the fluorescence change or bound radioactivity, respectively. With TNP-ATP three binding sites were determined at cytochrome c oxidase from bovine heart and liver, both with two dissociation constants Kd of about 0.2 and 0.9 microM. Trypsin treatment of the enzyme from bovine heart, resulted in one binding site with a Kd of 0.3 microM. The two-subunit enzyme of Paracoccus dentrificans had only one binding site with a Kd of 3.6 microM. The binding of [35S]ATP alpha S to cytochrome c oxidase was studied by equilibrium dialysis. With the enzyme of bovine heart seven and the enzyme of liver six high-affinity binding sites with apparent Kd's of 7.5 and 12 microM, respectively, were obtained. The two-subunit enzyme of Paracoccus denitrificans had one binding site with a Kd of 20 microM. The large number of binding sites at cytochrome c oxidase from bovine heart, mainly at nuclear coded subunits, was verified by photoaffinity labelling with 8-azido-[gamma-32P]ATP.

  19. NADPH Oxidases in Vascular Pathology

    PubMed Central

    Konior, Anna; Schramm, Agata; Czesnikiewicz-Guzik, Marta

    2014-01-01

    Abstract Significance: Reactive oxygen species (ROS) play a critical role in vascular disease. While there are many possible sources of ROS, nicotinamide adenine dinucleotide phosphate (NADPH) oxidases play a central role. They are a source of “kindling radicals,” which affect other enzymes, such as nitric oxide synthase endothelial nitric oxide synthase or xanthine oxidase. This is important, as risk factors for atherosclerosis (hypertension, diabetes, hypercholesterolemia, and smoking) regulate the expression and activity of NADPH oxidases in the vessel wall. Recent Advances: There are seven isoforms in mammals: Nox1, Nox2, Nox3, Nox4, Nox5, Duox1 and Duox2. Nox1, Nox2, Nox4, and Nox5 are expressed in endothelium, vascular smooth muscle cells, fibroblasts, or perivascular adipocytes. Other homologues have not been found or are expressed at very low levels; their roles have not been established. Nox1/Nox2 promote the development of endothelial dysfunction, hypertension, and inflammation. Nox4 may have a role in protecting the vasculature during stress; however, when its activity is increased, it may be detrimental. Calcium-dependent Nox5 has been implicated in oxidative damage in human atherosclerosis. Critical Issues: NADPH oxidase-derived ROS play a role in vascular pathology as well as in the maintenance of normal physiological vascular function. We also discuss recently elucidated mechanisms such as the role of NADPH oxidases in vascular protection, vascular inflammation, pulmonary hypertension, tumor angiogenesis, and central nervous system regulation of vascular function and hypertension. Future Directions: Understanding the role of individual oxidases and interactions between homologues in vascular disease is critical for efficient pharmacological regulation of vascular NADPH oxidases in both the laboratory and clinical practice. Antioxid. Redox Signal. 20, 2794–2814. PMID:24180474

  20. Structure of glycolate oxidase from spinach

    PubMed Central

    Lindqvist, Ylva; Brändén, Carl-Ivar

    1985-01-01

    A high-resolution structure determination of glycolate oxidase from spinach is reported. X-ray data were collected on films at the synchrotron radiation source in Daresbury, England. The structure was solved by using two heavy-atom derivatives and a solvent-flattening procedure developed by B.-C. Wang. The subunit structure is essentially a structure of the eight-stranded α/β-barrel type first described for triosephosphate isomerase. In addition, there are 70 residues at the NH2 terminus and 45 residues between strand four and helix four of the barrel, which are arranged in a helical domain outside the COOH end of the parallel strands of the barrel. The active site is in a cleft between these domains with the coenzyme FMN essentially bound to the barrel and a substrate analogue, thioglycolate, bound to the helical domain. The molecule is octameric with 422 symmetry and has a 15- to 20-Å-wide hole in the middle. PMID:16593616

  1. Higher direct bilirubin levels during mid-pregnancy are associated with lower risk of gestational diabetes mellitus.

    PubMed

    Liu, Chaoqun; Zhong, Chunrong; Zhou, Xuezhen; Chen, Renjuan; Wu, Jiangyue; Wang, Weiye; Li, Xiating; Ding, Huisi; Guo, Yanfang; Gao, Qin; Hu, Xingwen; Xiong, Guoping; Yang, Xuefeng; Hao, Liping; Xiao, Mei; Yang, Nianhong

    2017-01-01

    Bilirubin concentrations have been recently reported to be negatively associated with type 2 diabetes mellitus. We examined the association between bilirubin concentrations and gestational diabetes mellitus. In a prospective cohort study, 2969 pregnant women were recruited prior to 16 weeks of gestation and were followed up until delivery. The value of bilirubin was tested and oral glucose tolerance test was conducted to screen gestational diabetes mellitus. The relationship between serum bilirubin concentration and gestational weeks was studied by two-piecewise linear regression. A subsample of 1135 participants with serum bilirubin test during 16-18 weeks gestation was conducted to research the association between serum bilirubin levels and risk of gestational diabetes mellitus by logistic regression. Gestational diabetes mellitus developed in 8.5 % of the participants (223 of 2969). Two-piecewise linear regression analyses demonstrated that the levels of bilirubin decreased with gestational week up to the turning point 23 and after that point, levels of bilirubin were increased slightly. In multiple logistic regression analysis, the relative risk of developing gestational diabetes mellitus was lower in the highest tertile of direct bilirubin than that in the lowest tertile (RR 0.60; 95 % CI, 0.35-0.89). The results suggested that women with higher serum direct bilirubin levels during the second trimester of pregnancy have lower risk for development of gestational diabetes mellitus.

  2. Serum total bilirubin levels are negatively correlated with metabolic syndrome in aged Chinese women: a community-based study

    PubMed Central

    Zhong, P.; Sun, D.M.; Wu, D.H.; Li, T.M.; Liu, X.Y.; Liu, H.Y.

    2017-01-01

    We evaluated serum total bilirubin levels as a predictor for metabolic syndrome (MetS) and investigated the relationship between serum total bilirubin levels and MetS prevalence. This cross-sectional study included 1728 participants over 65 years of age from Eastern China. Anthropometric data, lifestyle information, and previous medical history were collected. We then measured serum levels of fasting blood-glucose, total cholesterol, triglycerides, and total bilirubin, as well as alanine aminotransferase activity. The prevalence of MetS and each of its individual component were calculated per quartile of total bilirubin level. Logistic regression was used to assess the correlation between serum total bilirubin levels and MetS. Total bilirubin level in the women who did not have MetS was significantly higher than in those who had MetS (P<0.001). Serum total bilirubin quartiles were linearly and negatively correlated with MetS prevalence and hypertriglyceridemia (HTG) in females (P<0.005). Logistic regression showed that serum total bilirubin was an independent predictor of MetS for females (OR: 0.910, 95%CI: 0.863–0.960; P=0.001). The present study suggests that physiological levels of serum total bilirubin might be an independent risk factor for aged Chinese women, and the prevalence of MetS and HTG are negatively correlated to serum total bilirubin levels. PMID:28146216

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

    PubMed Central

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

    2016-01-01

    Aim 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. Methods 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. Results 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. Conclusions Increases in serum bilirubin concentration were positively associated with a higher risk of incident MetS. Serum bilirubin increment might

  4. [Alternative oxidase in industrial fungi].

    PubMed

    Gu, Shuai; Liu, Qiang; He, Hao; Li, Shuang

    2015-01-01

    Filamentous fungi have been used in industrial fermentation extensively. Based on non-phosphorylating electron transport process, alternative respiration pathway (ARP) acts as an energy overflow, which can balance carbon metabolism and electron transport, allow the continuance of tricarboxylic acid cycle without the formation of ATP, and permit the turnover of carbon skeletons. Alternative respiration pathway also plays an important role in the stress response of fungi and the physiological function of conditioned pathogen. Alternative oxidase (AOX) is the terminal oxidase responsible for the activity of alternative respiration pathway, which exists widely in higher plants, parts of fungi and algae. Owing to the property that alternative oxidase (AOX) is sensitive to salicylhydroxamic acid (SHAM) and insensitive to conventional inhibitors of cytochrome respiration, alternative respiration pathway by AOX is also named as cyanide-resistant respiration (CRR). In recent years, the study of the alternative respiration pathway and alternative oxidase has been a hot topic in the area involving cellular respiration metabolism. In this review we summarized the latest research advances about the functions of alternative respiration pathway and alternative oxidase in industrial fungi.

  5. Associations between serum total bilirubin levels and functional dependence in the elderly.

    PubMed

    Kao, T W; Chou, C H; Wang, C C; Chou, C C; Hu, J; Chen, W L

    2012-11-01

    Many studies support the role of bilirubin as a cytoprotector in chronic inflammatory diseases, such as stroke and atherosclerosis. To investigate the relationship between serum total bilirubin levels and functional dependence in older adults. Data from the National Health and Nutrition Examination Survey (1999-2002) pertaining to 2235 old adults were analysed. All participants had given a household interview, providing information of five major domains on self-reported functional status (activities of daily living, instrumental activities of daily living, leisure and social activities, lower extremity mobility and general physical activities), had completed serum total bilirubin measurement, and a questionnaire regarding personal health. Poor performance was defined as experiencing difficulty with one or more items in a given domain. Functional dependence was defined as having three or more poor performances in the five major domains. Multiple logistic regression was performed together with quartile-based stratified odds ratio (OR) comparison and trend tests. The OR of functional dependence for each standard deviation increment in the serum total bilirubin level was 0.56 (P = 0.002). After additional adjustment, the inverse association remained essentially unchanged. In quartile-based analysis, participants with higher quartiles of serum total bilirubin tended to have lower ORs of functional dependence. The trends of lower likelihood of functional dependence across increasing quartiles of the serum total bilirubin level were statistically significant (P < 0.05 for all trends). Higher serum total bilirubin levels were associated with lower likelihood of functional dependence in older adults. © 2011 The Authors; Internal Medicine Journal © 2011 Royal Australasian College of Physicians.

  6. Development of a System Model for Non-Invasive Quantification of Bilirubin in Jaundice Patients

    NASA Astrophysics Data System (ADS)

    Alla, Suresh K.

    Neonatal jaundice is a medical condition which occurs in newborns as a result of an imbalance between the production and elimination of bilirubin. Excess bilirubin in the blood stream diffuses into the surrounding tissue leading to a yellowing of the skin. An optical system integrated with a signal processing system is used as a platform to noninvasively quantify bilirubin concentration through the measurement of diffuse skin reflectance. Initial studies have lead to the generation of a clinical analytical model for neonatal jaundice which generates spectral reflectance data for jaundiced skin with varying levels of bilirubin concentration in the tissue. The spectral database built using the clinical analytical model is then used as a test database to validate the signal processing system in real time. This evaluation forms the basis for understanding the translation of this research to human trials. The clinical analytical model and signal processing system have been successful validated on three spectral databases. First spectral database is constructed using a porcine model as a surrogate for neonatal skin tissue. Samples of pig skin were soaked in bilirubin solutions of varying concentrations to simulate jaundice skin conditions. The resulting skins samples were analyzed with our skin reflectance systems producing bilirubin concentration values that show a high correlation (R2 = 0.94) to concentration of the bilirubin solution that each porcine tissue sample is soaked in. The second spectral database is the spectral measurements collected on human volunteers to quantify the different chromophores and other physical properties of the tissue such a Hematocrit, Hemoglobin etc. The third spectral database is the spectral data collected at different time periods from the moment a bruise is induced.

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

    PubMed

    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.

  8. Catalase activity of cytochrome C oxidase assayed with hydrogen peroxide-sensitive electrode microsensor.

    PubMed

    Bolshakov, I A; Vygodina, T V; Gennis, R; Karyakin, A A; Konstantinov, A A

    2010-11-01

    An iron-hexacyanide-covered microelectrode sensor has been used to continuously monitor the kinetics of hydrogen peroxide decomposition catalyzed by oxidized cytochrome oxidase. At cytochrome oxidase concentration ~1 µM, the catalase activity behaves as a first order process with respect to peroxide at concentrations up to ~300-400 µM and is fully blocked by heat inactivation of the enzyme. The catalase (or, rather, pseudocatalase) activity of bovine cytochrome oxidase is characterized by a second order rate constant of ~2·10(2) M(-1)·sec(-1) at pH 7.0 and room temperature, which, when divided by the number of H2O2 molecules disappearing in one catalytic turnover (between 2 and 3), agrees reasonably well with the second order rate constant for H2O2-dependent conversion of the oxidase intermediate F(I)-607 to F(II)-580. Accordingly, the catalase activity of bovine oxidase may be explained by H2O2 procession in the oxygen-reducing center of the enzyme yielding superoxide radicals. Much higher specific rates of H2O2 decomposition are observed with preparations of the bacterial cytochrome c oxidase from Rhodobacter sphaeroides. The observed second order rate constants (up to ~3000 M(-1)·sec(-1)) exceed the rate constant of peroxide binding with the oxygen-reducing center of the oxidized enzyme (~500 M(-1)·sec(-1)) several-fold and therefore cannot be explained by catalytic reaction in the a(3)/Cu(B) site of the enzyme. It is proposed that in the bacterial oxidase, H2O2 can be decomposed by reacting with the adventitious transition metal ions bound by the polyhistidine-tag present in the enzyme, or by virtue of reaction with the tightly-bound Mn2+, which in the bacterial enzyme substitutes for Mg2+ present in the mitochondrial oxidase.

  9. The effect of elimination of environmental light on the metabolism of unconjugated bilirubin in the Gunn rat

    SciTech Connect

    Zenone, E.A.; Stoll, M.S.; Ostrow, J.D.

    1982-12-01

    In the homozygous jaundiced Gunn rat, bilirubin catabolism is augmented by intense illumination (phototherapy) and by induction of microsomal cytochrome P448. To assess the relative importance of less intense environmental light versus intrinsic mechanisms in the maintenance of bilirubin turnover, Gunn rats were kept for three weeks under either ordinary laboratory lighting (0.3-0.8 mW/cm2, wavelength range 400-600 nm) or in absolute darkness. No differences in plasma concentration, miscible pool, turnover of bilirubin, or in hepatic cytochrome P448 activity were noted between the two groups over this period. A greater than twofold increase in the biliary excretion of unconjugated bilirubin was noted in the animals maintained under light, but this represented only 2% of total bilirubin turnover. These results suggest that intrinsic(enzymatic .) pathways are of primary importance in the maintenance of bilirubin metabolism in the glucuronyltransferase-deficient state under ordinary levels of environmental light.

  10. The multicopper oxidase gene family in the brown planthopper, Nilaparvata lugens.

    PubMed

    Ye, Yu-Xuan; Pan, Peng-Lu; Kang, Dong; Lu, Jia-Bao; Zhang, Chuan-Xi

    2015-08-01

    The multicopper oxidase (MCO) family of enzymes includes laccases, ascorbate oxidases, bilirubin oxidases and a subgroup of metal oxidases. On the basis of a bioinformatics investigation, we identified 7 genes encoding putative multicopper oxidase proteins in the genome of the brown planthopper (BPH), Nilaparvata lugens (Hemiptera: Delphacidae). MCO1 and MCO2 are conserved, while others diverse in insects. Analysis of developmental and tissue-specific expression patterns revealed the following: NlMCO2 was mainly expressed in the integument, and its expression peaked periodically during molting; NlMCO3 was an ovary-specific MCO gene with a high expression level only at the adult stage; NlMCO4 was a salivary gland-specific MCO gene that was expressed at all developmental stages; NlMCO5 only had short-term expression in the middle of the fourth instar stage and was expressed mainly in the gut; NlMCO6 had a developmental expression pattern similar to that of NlMCO2 and was expressed in most N. lugens tissues; and NlMCO1 was expressed in most N. lugens tissues except for the testis, whereas NlMCO7 was mainly expressed in the gut and the Malpighian tube. BPHs injected with double-stranded RNA (dsRNA) targeting NlMCO2 failed to pigment and sclerotize, were colorless and soft-bodied and subsequently died in a short time. Lethal phenotypes were also observed in insects challenged by dsRNA targeting NlMCO6. However, no observable morphological or internal structural abnormality was obtained in the insects treated with dsRNA for NlMCO1, NlMCO3, NlMCO4, NlMCO5 or NlMCO7.

  11. Cardiolipin-depleted bovine heart cytochrome c oxidase: Binding stoichiometry and affinity for cardiolipin derivatives

    SciTech Connect

    Robinson, N.C.; Zborowski, J.; Talbert, L.H. )

    1990-09-25

    Detergent-solubilized bovine heart cytochrome c oxidase requires 2 mol of tightly bound cardiolipin (CL) per mole of monomeric complex for functional activity. Four lines of evidence support this conclusion: (1) Phospholipid depletion shows that two tightly bound CL's must remain associated with cytochrome c oxidase in order to maintain full electron transport activity. (2) Removal of the two tightly bound CL's correlates with decreased activity that is restored by reassociation of 2 mol of exogenous CL. (3) CL-depleted cytochrome c oxidase has two high-affinity binding sites for 2-({sup 14}C)acetylcardiolipin (AcCL), K{sub d,app} <0.1 {mu}M, that are not present in enzyme containing endogenous CL. (4) CL, monolysocardiolipin (MLCL), and dilysocardiolipin (DLCL) complete for AcCL binding with approximately the same relative affinities as those measured by the restoration of electron transport activity (MLCL competes much better than DLCL). However, MLCL and DLCL are only 60% and 15% as effective as CL in restoring maximum activity when they are bound to high-affinity sites. The binding specificity of CL, MLCL, DLCL, and some of their acylated derivatives indicates that the apolar tails are most important for binding, not the polar head group. The authors therefore, conclude that restoration of activity to CL-depleted cytochrome c oxidase is highly specific and requires the reassociation of CL, or structurally similar compounds, with two high-affinity binding sites.

  12. Expression of alternative oxidase in tomato

    SciTech Connect

    Kakefuda, M.; McIntosh, L. )

    1990-05-01

    Tomato fruit ripening is characterized by an increase in ethylene biosynthesis, a burst in respiration (i.e. the climacteric), fruit softening and pigmentation. As whole tomatoes ripened from mature green to red, there was an increase in the alternative oxidase capacity. Aging pink tomato slices for 24 and 48 hrs also showed an increase of alternative oxidase and cytochrome oxidase capacities. Monoclonal antibodies prepared to the Sauromatum guttatum alternative oxidase were used to follow the appearance of alternative oxidase in tomato fruits. There is a corresponding increase in a 36kDa protein with an increase in alternative oxidase capacity. Effects of ethylene and norbornadiene on alternative oxidase capacity were also studied. We are using an alternative oxidase cDNA clone from potato to study the expression of mRNA in ripening and wounded tomatoes to determine if the gene is transcriptionally regulated.

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

    PubMed

    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.

  14. Entropy Bounds and Entanglement

    NASA Astrophysics Data System (ADS)

    Fisher, Zachary

    The generalized covariant entropy bound, or Bousso bound, is a holographic bound on the entropy of a region of space in a gravitational theory. It bounds the entropy passing through certain null surfaces. The bound remains non-trivial in the weak-gravity limit, and provides non-trivial constraints on the entropy of ordinary quantum states even in a regime where gravity is negligible. In the first half of this thesis, we present a proof of the Bousso bound in the weak-gravity regime within the framework of quantum field theory. The bound uses techniques from quantum information theory which relate the energy and entropy of quantum states. We present two proofs of the bound in free and interacting field theory. In the second half, we present a generalization of the Bousso bound called the quantum focussing conjecture. Our conjecture is a bound on the rate of entropy generation in a quantum field theory coupled semiclassically to gravity. The conjecture unifies and generalizes several ideas in holography. In particular, the quantum focussing conjecture implies a bound on entropies which is similar to, but subtly different from, the Bousso bound proven in the first half. The quantum focussing conjecture implies a novel non-gravitational energy condition, the quantum null energy condition, which gives a point-wise lower bound on the null-null component of the stress tensor of quantum matter. We give a proof of this bound in the context of free and superrenormalizable bosonic quantum field theory.

  15. A Genome-Wide Association Study of Total Bilirubin and Cholelithiasis Risk in Sickle Cell Anemia

    PubMed Central

    Milton, Jacqueline N.; Sebastiani, Paola; Solovieff, Nadia; Hartley, Stephen W.; Bhatnagar, Pallav; Arking, Dan E.; Dworkis, Daniel A.; Casella, James F.; Barron-Casella, Emily; Bean, Christopher J.; Hooper, W. Craig; DeBaun, Michael R.; Garrett, Melanie E.; Soldano, Karen; Telen, Marilyn J.; Ashley-Koch, Allison; Gladwin, Mark T.; Baldwin, Clinton T.; Steinberg, Martin H.; Klings, Elizabeth S.

    2012-01-01

    Serum bilirubin levels have been associated with polymorphisms in the UGT1A1 promoter in normal populations and in patients with hemolytic anemias, including sickle cell anemia. When hemolysis occurs circulating heme increases, leading to elevated bilirubin levels and an increased incidence of cholelithiasis. We performed the first genome-wide association study (GWAS) of bilirubin levels and cholelithiasis risk in a discovery cohort of 1,117 sickle cell anemia patients. We found 15 single nucleotide polymorphisms (SNPs) associated with total bilirubin levels at the genome-wide significance level (p value <5×10−8). SNPs in UGT1A1, UGT1A3, UGT1A6, UGT1A8 and UGT1A10, different isoforms within the UGT1A locus, were identified (most significant rs887829, p = 9.08×10−25). All of these associations were validated in 4 independent sets of sickle cell anemia patients. We tested the association of the 15 SNPs with cholelithiasis in the discovery cohort and found a significant association (most significant p value 1.15×10−4). These results confirm that the UGT1A region is the major regulator of bilirubin metabolism in African Americans with sickle cell anemia, similar to what is observed in other ethnicities. PMID:22558097

  16. Point Spectroscopy System for Noncontact and Noninvasive Prediction of Transcutaneous Bilirubin Concentration

    NASA Astrophysics Data System (ADS)

    Ong, P. E.; K. C Huong, Audrey

    2017-08-01

    This paper presents the use of a point spectroscopy system to determine one’s transcutaneous bilirubin level using Modified Lambert Beer model and the developed fitting routine. This technique required a priori knowledge of extinction coefficient of bilirubin and hemoglobin components in the wavelength range of 440-500 nm for the prediction of the required parameter value. This work was conducted on different skin sites of six healthy Asians namely on the thenar region of the palm of their hand, back of the hand, posterior and anterior forearm. The obtained results revealed the lowest mean transcutaneous bilirubin concentration of 0.44±0.3 g/l predicted for palm site while the highest bilirubin level of 0.98±0.2 g/l was estimated for posterior forearm. These values were also compared with that presented in the literature. This study found considerably good consistency in the value predicted for different subjects especially at the thenar region of the palm. This work concluded that the proposed system and technique may be suitably served as an alternative means to noncontact and noninvasive measurement of one’s transcutaneous bilirubin level at palm site.

  17. The effect of steroids and nucleotides on solubilized bilirubin uridine diphosphate glucuronyltransferase

    PubMed Central

    Adlard, B. P. F.; Lathe, G. H.

    1970-01-01

    1. It was confirmed that bilirubin glucuronyltransferase can be obtained in solubilized form from rat liver microsomes. 2. Michaelis–Menten kinetics were not followed by the enzyme with bilirubin as substrate when the bilirubin/albumin ratio was varied. High concentrations of bilirubin were inhibitory. 3. The Km for UDP-glucuronic acid at the optimum bilirubin concentration was 0.46mm. 4. Low concentrations of Ca2+ were inhibitory in the absence of Mg2+ but stimulatory in its presence; the converse applied for EDTA. 5. UDP-N-acetylglucosamine and UDP-glucose enhanced conjugation by untreated, but not by solubilized microsomes. 6. The apparent 9.5-fold increase in activity after solubilization was probably due to the absence of UDP-glucuronic acid pyrophosphatase activity in the solubilized preparation. 7. The activation of solubilized enzyme activity by ATP was considered to be a result of chelation of inhibitory metal ions. 8. The solubilized enzyme activity was inhibited by UMP and UDP. The effect of UMP was not competitive with respect to UDP-glucuronic acid. 9. A number of steroids inhibited the solubilized enzyme activity. The competitive effects of stilboestrol, oestrone sulphate and 3β-hydroxyandrost-5-en-17-one, with respect to UDP-glucuronic acid, may be explained on an allosteric basis. PMID:4251180

  18. Potential Cardiovascular Risk Protection of Bilirubin in End-Stage Renal Disease Patients under Hemodialysis

    PubMed Central

    do Sameiro-Faria, Maria; Kohlova, Michaela; Ribeiro, Sandra; Rocha-Pereira, Petronila; Teixeira, Laetitia; Nascimento, Henrique; Reis, Flávio; Miranda, Vasco; Bronze-da-Rocha, Elsa; Quintanilha, Alexandre; Belo, Luís; Costa, Elísio; Santos-Silva, Alice

    2014-01-01

    We evaluated the potential cardiovascular risk protection of bilirubin in hemodialysis (HD) patients. An enlarged set of studies were evaluated in 191 HD patients, including hematological study, lipid profile, iron metabolism, nutritional, inflammatory markers, and dialysis adequacy. The TA duplication screening in the UDP-glucuronosyltransferase 1 A1 (UGT1A1) promoter region was also performed. The UGT1A1 genotype frequencies in HD patients were 49.2%, 42.4%, and 8.4% for 6/6, 6/7, and 7/7 genotypes, respectively. Although no difference was found in UGT1A1 genotype distribution between the three tertiles of bilirubin, significant differences were found with increasing bilirubin levels, namely, a decrease in platelet, leukocyte, and lymphocyte counts, transferrin, oxidized low-density lipoprotein (ox-LDL), ox-LDL/low-density lipoprotein cholesterol ratio, apolipoprotein (Apo) A, Apo B, and interleukin-6 serum levels and a significant increased concentration of hemoglobin, hematocrit, erythrocyte count, iron, transferrin saturation, Apo A/Apo B ratio, adiponectin, and paraoxonase 1 serum levels. After adjustment for age these results remained significant. Our data suggest that higher bilirubin levels are associated with beneficial effects in HD patients, by improving lipid profile and reducing the inflammatory grade, which might contribute to increase in iron availability. These results suggest a potential cardiovascular risk protection of bilirubin in HD patients. PMID:25276769

  19. Evaluation of region selective bilirubin-induced brain damage as a basis for a pharmacological treatment

    PubMed Central

    Dal Ben, Matteo; Bottin, Cristina; Zanconati, Fabrizio; Tiribelli, Claudio; Gazzin, Silvia

    2017-01-01

    The neurologic manifestations of neonatal hyperbilirubinemia in the central nervous system (CNS) exhibit high variations in the severity and appearance of motor, auditory and cognitive symptoms, which is suggestive of a still unexplained selective topography of bilirubin-induced damage. By applying the organotypic brain culture (OBC: preserving in vitro the cellular complexity, connection and architecture of the in vivo brain) technique to study hyperbilirubinemia, we mapped the regional target of bilirubin-induced damage, demonstrated a multifactorial toxic action of bilirubin, and used this information to evaluate the efficacy of drugs applicable to newborns to protect the brain. OBCs from 8-day-old rat pups showed a 2–13 fold higher sensitivity to bilirubin damage than 2-day-old preparations. The hippocampus, inferior colliculus and cerebral cortex were the only brain regions affected, presenting a mixed inflammatory-oxidative mechanism. Glutamate excitotoxicity was appreciable in only the hippocampus and inferior colliculus. Single drug treatment (indomethacin, curcumin, MgCl2) significantly improved cell viability in all regions, while the combined (cocktail) administration of the three drugs almost completely prevented damage in the most affected area (hippocampus). Our data may supports an innovative (complementary to phototherapy) approach for directly protecting the newborn brain from bilirubin neurotoxicity. PMID:28102362

  20. Relationship Between the Serum Total Bilirubin and Inflammation in Patients With Psoriasis Vulgaris.

    PubMed

    Zhou, Zhen-Xing; Chen, Jian-Kui; Hong, Yan-Ying; Zhou, Ru; Zhou, Dong-Mei; Sun, Li-Yun; Qin, Wen-Li; Wang, Tian-Cheng

    2016-09-01

    Psoriasis is a chronic and recurrent inflammatory skin disease. Previous studies have shown that bilirubin has anti-inflammation and antioxidant effects. However, the various roles of bilirubin in psoriasis patients are still unclear. To investigate the serum total bilirubin (TB) level in the individuals with psoriasis vulgaris and further evaluate the relationship between serum TB concentration and C-reactive protein (CRP) to clarify the effect of bilirubin on inflammation. A total of 214 patients with psoriasis vulgaris and 165 age- and gender-matched healthy control subjects were recruited. The peripheral leukocyte count (white blood cell, WBC) and differential, serum biochemical and immunologic indexes including serum TB, immunoglobulin (Ig) G, IgA, IgM, complement C3 and C4 , as well as serum CRP concentrations were measured. Results showed that the serum TB level decreased significantly and peripheral WBC, neutrophil, and serum CRP concentrations increased significantly in patients with psoriasis vulgaris. Meanwhile, the serum CRP was negatively correlated with serum TB levels but positively correlated with peripheral WBC and the Psoriasis Area and Severity Index (PASI). Logistic regression analysis showed that the serum TB was a protective factor for psoriasis vulgaris. The present study suggests that lower serum TB is associated with the enhancement of the inflammatory response in psoriasis vulgaris. Therefore, lower serum TB has a prognostic significance for worsening psoriasis vulgaris. Bilirubin may play a crucial role in inflammation by contributing to the inhibition of the inflammatory response. © 2016 Wiley Periodicals, Inc.

  1. The impact of the UGT1A1*60 allele on bilirubin serum concentrations.

    PubMed

    Pasternak, Amy L; Crews, Kristine R; Caudle, Kelly E; Smith, Colton; Pei, Deqing; Cheng, Cheng; Broeckel, Ulrich; Gaur, Aditya H; Hankins, Jane; Relling, Mary V; Haidar, Cyrine E

    2017-01-01

    Identify the functional status of the uridine-diphosphate glucuronyl transferase 1A1 (UGT1A1) -3279T>G (*60) variant. Retrospective review of clinically obtained serum bilirubin concentrations in pediatric patients to evaluate the association of the UGT1A1 -3279T>G (*60) variant with bilirubin concentrations and assessed linkage disequilibrium of the UGT1A1 -3279T>G (*60) and A(TA)7TAA (*28) variants. Total bilirubin concentration did not differ between patients who had a UGT1A1*1/*1 diplotype and patients homozygous for the UGT1A1 -3279T>G (*60/*60) variant. Total bilirubin concentration was lower in patients homozygous for the UGT1A1 -3279T>G (*60/*60) variant than in patients homozygous for the UGT1A1 A(TA)7TAA (*28/*28) variant (p < 0.01). The -3279T>G (*60) and A(TA)7TAA (*28) variants were in strong incomplete linkage disequilibrium in both black and white patients. The presence of the UGT1A1 -3279T>G (*60) variant is not associated with increased bilirubin concentrations.

  2. Bilirubin production in healthy term infants as measured by carbon monoxide in breath.

    PubMed

    Stevenson, D K; Vreman, H J; Oh, W; Fanaroff, A A; Wright, L L; Lemons, J A; Verter, J; Shankaran, S; Tyson, J E; Korones, S B

    1994-10-01

    To describe total bilirubin production in healthy term infants, we measured the end-tidal breath CO, corrected for ambient CO (ETCOc), with an automated sampler and electrochemical (EC) CO instrument. For infants of mothers with a negative Coombs' test, the ETCOc was 1.3 +/- 0.7 microL/L (n = 397) and the serum bilirubin on day 3 postpartum was 73 +/- 35 mg/L (n = 381). In contrast, the ETCOc for infants with ABO or Rh incompatibility, a positive direct Coombs' test, and bilirubin > 130 mg/L (n = 9) was significantly higher, 1.8 +/- 0.8 microL/L, than for those who had a positive Coombs' test result but whose bilirubin was < or = 130 mg/L (n = 12), 1.0 +/- 0.5 microL/L (P < 0.05). At 2 to 8 h postpartum seven term babies from mothers with insulin-dependent diabetes had ETCOc of 1.8 +/- 0.7 microL/L, significantly higher than that in the other term infants [1.3 +/- 0.7 microL/L (n = 390), P < 0.04]. Their bilirubin concentration at 72 +/- 12 h was also higher: 121 +/- 45 mg/L (n = 7) vs 73 +/- 34 mg/L (n = 374; P = 0.03). We conclude that ETCOc measurements may be helpful in understanding the mechanisms of jaundice in healthy term infants in a variety of conditions.

  3. The association between indirect bilirubin levels and liver fibrosis due to chronic hepatitis C virus infection.

    PubMed

    Cengiz, Mustafa; Yılmaz, Guldal; Ozenirler, Seren

    2014-08-01

    We proposed to evaluate the association between serum indirect bilirubin levels and liver fibrosis in patients with chronic hepatitis C (CHC) genotype 1b. Biopsy proven CHC genotype 1b patients' demographics, clinical and histopathological characteristics were evaluated. Logistic regression analysis was done to evaluate the clinical, laboratory and demographic features of the histologically proven liver fibrosis in CHC patients. A total of 112 biopsy proven CHC genotype 1b patients were enrolled into the study. Liver fibrosis scores were measured by using Ishak fibrosis scores and were divided into two groups; fibrosis scores ≤ 2 were categorized as mild fibrosis, 82 patients (73.2%), whereas fibrosis scores >2 were categorized as advanced fibrosis group, 30 patients (26.8%). Patients with advanced fibrosis had lower indirect bilirubin levels than the mild fibrosis group (0.28 ± 0.02 mg/dl vs. 0.44 ± 0.032 mg/dl, p<0.001, respectively). Indirect bilirubin level was negatively correlated with advanced fibrosis scores (r=-0.416 and p<0.001). In multivariate logistic regression analysis, low indirect bilirubin level was an independent predicting factor of advanced liver fibrosis (OR: 0.001, 95% CI: 0.0-0.005, p<0.001). There is an inverse relationship between indirect bilirubin levels and advanced liver fibrosis caused by CHC genotype 1b.

  4. Bilirubin degradation in methanol induced by continuous UV-B irradiation: a UHPLC--ESI-MS study.

    PubMed

    Stanojević, J S; Zvezdanović, J B; Marković, D Z

    2015-04-01

    Degradation of bilirubin in aerobic methanol solution by continuous UV-B irradiation has been investigated in this work. The purpose of this study was to shed more light on bilirubin interaction with the UV-B component of natural sunlight, since bilirubin is a very efficient UV-B absorber located in the skin epidermis. The degradation products have been detected and studied by a combined method of Ultra High Performance Liquid Chromatography-Electrospray Ionization Mass Spectrometry (UHPLC-ESI-MS). Bilirubin, a toxic pigment which itself is a product of (hemoglobin) degradation in organisms, undergoes its own degradation under aerobic conditions of UV-B continuous irradiation (e.g. photooxidation) that can be partly self-sensitized. Two dipyrrolic structures have been identified as a result of the bilirubin degradation, not including the bilirubin derivative biliverdin whose increase in the irradiated system is synchronous with a time dynamics of bilirubin degradation. It appears that one of dipyrrolic products originates directly from bilirubin and biliverdin molecules, while the other one is probably connected to bilirubin self-sensitized degradation. The precursor role of biliverdin in the degradation process--related to the detected dipyrroles--has not been confirmed.

  5. Efficient voltammetric discrimination of free bilirubin from uric acid and ascorbic acid by a CVD nanographite-based microelectrode.

    PubMed

    Taurino, Irene; Van Hoof, Viviane; Magrez, Arnaud; Forró, László; De Micheli, Giovanni; Carrara, Sandro

    2014-12-01

    We report a novel electrochemical sensor based on nanographite grown on platinum microelectrodes for the determination of bilirubin in the presence of normal concentrations of albumin. The albumin is a protein with an intrinsic ability to bind the bilirubin therefore reducing the concentration of the free electroactive metabolite in human fluids. In addition, the proposed device permits the discrimination of free bilirubin from two interferents, uric acid and ascorbic acid, by the separation of their oxidation peaks in voltammetry. Preliminary measurements in human serum prove that the proposed nanostructured platform can be used to detect bilirubin.

  6. Continuous de novo biosynthesis of haem and its rapid turnover to bilirubin are necessary for cytoprotection against cell damage.

    PubMed

    Takeda, Taka-aki; Mu, Anfeng; Tai, Tran Tien; Kitajima, Sakihito; Taketani, Shigeru

    2015-05-20

    It is well known that haem serves as the prosthetic group of various haemoproteins that function in oxygen transport, respiratory chain, and drug metabolism. However, much less is known about the functions of the catabolites of haem in mammalian cells. Haem is enzymatically degraded to iron, carbon monoxide (CO), and biliverdin, which is then converted to bilirubin. Owing to difficulties in measuring bilirubin, however, the generation and transport of this end product remain unclear despite its clinical importance. Here, we used UnaG, the recently identified bilirubin-binding fluorescent protein, to analyse bilirubin production in a variety of human cell lines. We detected a significant amount of bilirubin with many non-blood cell types, which was sensitive to inhibitors of haem metabolism. These results suggest that there is a basal level of haem synthesis and its conversion into bilirubin. Remarkably, substantial changes were observed in the bilirubin generation when cells were exposed to stress insults. Since the stress-induced cell damage was exacerbated by the pharmacological blockade of haem metabolism but was ameliorated by the addition of biliverdin and bilirubin, it is likely that the de novo synthesis of haem and subsequent conversion to bilirubin play indispensable cytoprotective roles against cell damage.

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

    PubMed

    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.

  8. Viscosity bound versus the universal relaxation bound

    NASA Astrophysics Data System (ADS)

    Hod, Shahar

    2017-10-01

    For gauge theories with an Einstein gravity dual, the AdS/CFT correspondence predicts a universal value for the ratio of the shear viscosity to the entropy density, η / s = 1 / 4 π. The holographic calculations have motivated the formulation of the celebrated KSS conjecture, according to which all fluids conform to the lower bound η / s ≥ 1 / 4 π. The bound on η / s may be regarded as a lower bound on the relaxation properties of perturbed fluids and it has been the focus of much recent attention. In particular, it was argued that for a class of field theories with Gauss-Bonnet gravity dual, the shear viscosity to entropy density ratio, η / s, could violate the conjectured KSS bound. In the present paper we argue that the proposed violations of the KSS bound are strongly constrained by Bekenstein's generalized second law (GSL) of thermodynamics. In particular, it is shown that physical consistency of the Gauss-Bonnet theory with the GSL requires its coupling constant to be bounded by λGB ≲ 0 . 063. We further argue that the genuine physical bound on the relaxation properties of physically consistent fluids is ℑω(k > 2 πT) > πT, where ω and k are respectively the proper frequency and the wavenumber of a perturbation mode in the fluid.

  9. Anemia, bilirubin, and cardiovascular autonomic neuropathy in patients with type 2 diabetes.

    PubMed

    Chung, Jin Ook; Park, Seon-Young; Cho, Dong Hyeok; Chung, Dong Jin; Chung, Min Young

    2017-04-01

    To investigate the relationship among anemia, physiological serum bilirubin levels, and cardiovascular autonomic neuropathy (CAN) in subjects with type 2 diabetes. In total, 2230 subjects with type 2 diabetes were evaluated in this cross-sectional study. CAN was diagnosed with a cardiovascular reflex test. The prevalence of anemia was greater in subjects with CAN. In multivariable analysis, the relationship between anemia and CAN remained statistically significant after adjusting for the risk factors (odds ratio [OR] 1.39; 95% confidence interval [CI] 1.07-1.80, P = .015). Additional adjustment for serum bilirubin concentrations abolished this relationship (OR 1.20, 95% CI 0.91-1.58, P = .189). Anemia is positively associated with the prevalence of CAN in subjects with type 2 diabetes. In addition, our results suggest that the putative increased CAN risk associated with anemia might be mediated by a correlated decrease in serum bilirubin levels.

  10. Conical intersection in a bilirubin model A possible pathway for phototherapy of neonatal jaundice

    NASA Astrophysics Data System (ADS)

    Zietz, Burkhard; Blomgren, Fredrik

    2006-03-01

    Phototherapy of neonatal jaundice involves Z- E-isomerisation around an exocyclic double bond in bilirubin. Our results of a CASSCF study on dipyrrinone, a bilirubin model, show a conical intersection between the ground and first excited singlet states associated with the Z- E-isomerisation. The conical intersection, located ca. 50 kJ/mol below the Franck-Condon-point, together with the S 1 minimum, ca. 50 kJ/mol below the conical intersection, are able to explain the available time-resolved spectroscopic data (the very short lifetime of the initially excited state and transient 'dark state' intermediate) as well as bilirubin's very low fluorescence quantum yield and the medium-efficient photoisomerisation reaction.

  11. [Clinical characteristics of bilirubin encephalopathy in Chinese newborn infants-a national multicenter survey].

    PubMed

    2012-05-01

    Bilirubin encephalopathy continued to be reported worldwide. This multicenter study was conducted to explore the clinical characteristics, comorbidities and prognosis of bilirubin encephalopathy in China. The survey was conducted in 33 level III hospitals. Clinical charts of infants with diagnosis of bilirubin encephalopathy or kernicterus at discharge were reviewed. The data were collected by a detaild questionnaire and analyzed. From January to December in 2009, 348 cases of bilirubin encephalopathy were reported from 28 hospitals. The mean birth weight was (3112.4 ± 599.6) grams, mean gestational age was (38.3 ± 2.3) weeks; 291 (83.6%) cases were term infants, 40 (11.5%) cases were late-preterm infants, and 11 (3.2%) cases were early preterm infants. After admission, the highest bilirubin level was (478.1 ± 175.8) µmol/L. Of all the 348 cases, the age at admission was (7.3 ± 5.4) days; 247 (71.0%) cases were admitted before 7 days of age, 24 (6.9%) cases were admitted after 14 days of age. Most of the cases (86.2%) were complicated with other conditions, including bacterial infection (52.6%), ABO incompatibility (29.9%), and perinatal asphyxia (10.1%). A total of 131 infants (37.6%) underwent an exchange transfusion. Use of albumin, intravenous immunoglobulin was also common (68.7% and 44.0% respectively). A total of 52 cases were of minority ethnic groups, with significantly higher rate of G6PD deficiency than Han ethnicity cases. During the hospitalization and follow up, 36 infants died, and 125 infants (35.9%) were lost to follow up. Bilirubin encephalopathy is still not rare in China, the establishment of a population-based reporting system and prevention of kernicterus remain a high priority among public health institutions.

  12. Parental infant jaundice colour card design successfully validated by comparing it with total serum bilirubin.

    PubMed

    Xue, Guo-Chang; Ren, Ming-Xing; Shen, Lin-Na; Zhang, Li-Wen

    2016-12-01

    We designed a jaundice colour card that could be used by the parents of neonates and validated it by comparing it with total serum bilirubin levels. There were 106 term Chinese neonates in the study. The majority weighed between 2500 g and 3499 g (63%) and had a gestational age of 37-40 weeks (77%). The jaundice colour card and photometric determination were used to screen for neonatal jaundice and compared with serum bilirubin. The bilirubin levels were measured by mothers using the jaundice colour card, and 67% of the measurements were taken at 11-20 days (range 3-30). The measurements at the infant's forehead, cheek and sternum showed strong correlations with total serum bilirubin. The mean differences between the total serum bilirubin and the jaundice colour card measurements from the forehead, cheek and sternum were 1.9 mg/dL, 0.3 mg/dL and 1.5 mg/dL, respectively. When total serum bilirubin >13 mg/dL was used as the cut-off point, the areas under the receiver operating characteristics curves were 0.934 for the forehead, 0.985 for the cheek and 0.966 for the sternum. We established the validity of the jaundice colour card as a parental measurement tool for jaundice in Chinese neonates, and the cheek was the best measurement site. ©2016 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

  13. Genetic influences on serum bilirubin in American Indians: The Strong Heart Family Study.

    PubMed

    Melton, Phillip E; Haack, Karin; Göring, Harald H; Laston, Sandy; Umans, Jason G; Lee, Elisa T; Fabsitz, Richard R; Devereux, Richard B; Best, Lyle G; Maccluer, Jean W; Almasy, Laura; Cole, Shelley A

    2011-01-01

    To identify genetic variation influencing serum bilirubin levels in American Indians, we performed genome-wide screening and association analyses in the Strong Heart Family Study. Bilirubin is an endogenous antioxidant that has demonstrated an inverse relationship with cardiovascular disease. Genetic variation within the promoter region of uridine diphosphate glucuronosyltransferase (UGT1A1) on chromosome 2q has been associated with elevated serum bilirubin levels in European populations. However, no study has investigated the UGT1A1 promoter in American Indians. Statistical analyses were carried out with 3,484 participants aged 14 to 93 years recruited from three geographic areas in the United States; Arizona, Oklahoma, and North and South Dakota. Variance components linkage analysis detected a quantitative trait locus (QTL) for bilirubin on chromosome 2q in the combined centers (LOD = 6.61, P = 4.24 × 10⁻⁶) and in Oklahoma (LOD = 5.65, P = 4.57 24 × 10⁻⁵). Genetic association of the UGT1A1 promoter polymorphism was significant for all geographic locations. After adjustment using conditional linkage for UGT1A1 promoter variance, the linkage signal dropped to 1.10 in the combined sample and to 3.32 (P = 0.02) in Oklahoma, indicating this polymorphism is not completely responsible for the linkage signal in American Indians. We also detected suggestive linkage signals in the Dakotas on chromosome 10p12 (LOD = 2.18) and in the combined centers (LOD = 2.24) on chromosome 10q21. Replication of a serum bilirubin QTL on chromosome 2q in American Indians implicates UGT1A1 but further genotyping is warranted to identify additional causative polymorphisms. Evidence also supports a potential novel locus for bilirubin on chromosome 10. © 2010 Wiley-Liss, Inc.

  14. Influence of light and time on bilirubin degradation in CSF spectrophotometry for subarachnoid haemorrhage.

    PubMed

    Foroughi, Mansoor; Parikh, Dhruv; Wassell, Julie; Hatfield, Richard

    2010-08-01

    Investigation of the influence of light on bilirubin degradation over time in cerebrospinal fluid (CSF) specimens from patients with computed tomography (CT) positive subarachnoid haemorrhage (SAH). Twenty-nine CSF samples were analysed from 23 patients with CT-positive SAH. Samples were divided into two cohorts - one half being stored in the dark, the other in normal room light conditions. Samples were assayed by spectrophotometry 0, 1, 2, 6, 19, 24 and 48 h post-storage. Net bilirubin absorbance (NBA) was measured in absorbance units (AU) by determining the optical density at 476 nm. In 27 of 28 (96%) samples stored in light conditions and 21 of 29 (72%) samples stored in dark, a decline in the amount of bilirubin detected in CSF over time was observed. The rate of bilirubin degradation over 24 h for CSF samples stored in the light ranged from 0.0001 to 0.0048 AU/h (mean 0.0020 AU/h), and was significantly greater (p < 0.01) than the rate of degradation in the dark, which ranged from 0 to 0.0024 AU/h (mean 0.0005 AU/h). CSF bilirubin samples are susceptible to the same photodegradation as shown in serum bilirubin samples. The rate of degradation is not predictable or consistent. This photodegradation may potentially produce false-negative results in the diagnosis of SAH. If spectrophotometry cannot be carried out immediately, all such CSF samples should at least be centrifuged immediately, the supernatant protected from light as soon as possible and the collection and analysis times provided in the report.

  15. Sensitizing effect of Z,Z-bilirubin IXα and its photoproducts on enzymes in model solutions

    NASA Astrophysics Data System (ADS)

    Plavskii, V. Yu.; Mostovnikov, V. A.; Tret'yakova, A. I.; Mostovnikova, G. R.

    2008-05-01

    In model systems, we have studied side effects which may be induced by light during phototherapy of hyperbilirubinemia (jaundice) in newborn infants, with the aim of reducing the Z,Z-bilirubin IXα (Z,Z-BR IXα) level. We have shown that the sensitizing effect of Z,Z-BR IXα, localized at strong binding sites of the human serum albumin (HSA) macromolecule, is primarily directed at the amino acid residues of the carrier protein and does not involve the molecules of the enzyme (lactate dehydrogenase (LDH)) present in the buffer solution. The detected photodynamic damage to LDH is due to sensitization by bilirubin photoisomers, characterized by lower HSA association constants and located (in contrast to native Z,Z-BR IXα) on the surface of the HSA protein globule. Based on study of the spectral characteristics of the photoproducts of Z,Z-BR IXα and comparison of their accumulation kinetics in solution and the enzyme photo-inactivation kinetics, we concluded that the determining role in sensitized damage to LDH is played by lumirubin. The photosensitization effect depends on the wavelength of the radiation used for photoconversion of bilirubin. When (at the beginning of exposure) we make sure that identical numbers of photons are absorbed by the pigment in the different spectral ranges, the side effect is minimal for radiation corresponding to the long-wavelength edge of the bilirubin absorption band. We have shown that for a bilirubin/HSA concentration ratio >2 (when some of the pigment molecules are sorbed on the surface of the protein globule), the bilirubin can act as a photosensitizing agent for the enzyme present in solution. We discuss methods for reducing unfavorable side effects of light on the body of newborn infants during phototherapy of hyperbilirubinemia.

  16. Protein-encapsulated bilirubin: paving the way to a useful probe for singlet oxygen.

    PubMed

    Pimenta, Frederico M; Jensen, Jan K; Etzerodt, Michael; Ogilby, Peter R

    2015-04-01

    When dissolved in a bulk solvent, bilirubin efficiently removes singlet molecular oxygen, O2(a(1)Δg), through a combination of chemical reactions and by promoting the O2(a(1)Δg)→O2(X(3)Σg(-)) nonradiative transition to populate the ground state of oxygen. To elucidate how such processes can be exploited in the development of a biologically useful fluorescent probe for O2(a(1)Δg), pertinent photophysical and photochemical parameters of bilirubin encapsulated in a protein were determined. The motivation for studying a protein-encapsulated system reflects the ultimate desire to (a) use genetic engineering to localize the probe at a specific location in a living cell, and (b) provide a controlled environment around the chromophore/fluorophore. Surprisingly, explicit values of oxygen- and O2(a(1)Δg)-dependent parameters that characterize the behavior of a given chromophore/fluorophore encased in a protein are not generally available. To the end of quantifying the effects of such an encasing protein, a recently discovered bilirubin-binding protein isolated from a Japanese eel was used. The data show that this system indeed preferentially responds to O2(a(1)Δg) and not to the superoxide ion. However, this protein not only shields bilirubin such that the rate constants for interaction with O2(a(1)Δg) decrease relative to what is observed in a bulk solvent, but the fraction of the total O2(a(1)Δg)-bilirubin interaction that results in a chemical reaction between O2(a(1)Δg) and bilirubin also decreases appreciably. The rate constants thus obtained provide a useful starting point for the general design and development of reactive protein-encased fluorescent probes for O2(a(1)Δg).

  17. Spectral fluorescence and polarization characteristics of Z,Z-bilirubin IXα

    NASA Astrophysics Data System (ADS)

    Plavskii, V. Yu.; Mostovnikov, V. A.; Mostovnikova, G. R.; Tret'yakova, A. I.

    2007-01-01

    We have studied the spectral fluorescence and polarization characteristics of Z,Z-bilirubin IXα, at room temperature in chloroform and in aqueous buffer medium, within an equilibrium complex with human serum albumin (HSA), and also under low temperature conditions (T = -100°C) in isobutyl alcohol. We have observed a bathochromic shift of the fluorescence spectra, which is most pronounced for the bilirubin-albumin complex. The following are considered as possible reasons for the observed dependence of the position of the fluorescence (fluorescence excitation) spectra on the excitation (detection) wavelength: structural and spectral differences between the chromophores making up the bilirubin molecule; conformational heterogeneity of the pigment in solution; a contribution to the fluorescence from molecules which have not completed the vibrational relaxation process; inhomogeneous orientational broadening of the levels; heterogeneity of the microenvironment of the chromophores in the protein matrix. We show that polarized fluorescence of bilirubin occurs at room temperature, due to the anomalously short fluorescence lifetime τ (picosecond or subpicosecond ranges). Despite such a short τ, the absorption and emission polarization spectra suggest the presence of intramolecular nonradiative singlet-singlet energy transfer when bilirubin is excited to high vibrational sublevels of the S1 state (degree of polarization p = 0.11-0.12). When fluorescence is excited on the long-wavelength slope of the absorption band, no transfer occurs: the degree of polarization (p = 0.46-0.47) is close to the limiting value (p = 0.50). We discuss the question of the role played by exciton interactions between chromophores in the bilirubin molecule when it is excited.

  18. Bound states and the Bekenstein bound

    SciTech Connect

    Bousso, Raphael

    2003-10-16

    We explore the validity of the generalized Bekenstein bound, S<= pi M a. We define the entropy S as the logarithm of the number of states which have energy eigenvalue below M and are localized to a flat space region of width alpha. If boundary conditions that localize field modes are imposed by fiat, then the bound encounters well-known difficulties with negative Casimir energy and large species number, as well as novel problems arising only in the generalized form. In realistic systems, however, finite-size effects contribute additional energy. We study two different models for estimating such contributions. Our analysis suggests that the bound is both valid and nontrivial if interactions are properly included, so that the entropy S counts the bound states of interacting fields.

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

    PubMed

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

    2014-09-01

    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.

  20. A Hypothesis for Using Pathway Genetic Load Analysis for Understanding Complex Outcomes in Bilirubin Encephalopathy

    PubMed Central

    Riordan, Sean M.; Bittel, Douglas C.; Le Pichon, Jean-Baptiste; Gazzin, Silvia; Tiribelli, Claudio; Watchko, Jon F.; Wennberg, Richard P.; Shapiro, Steven M.

    2016-01-01

    Genetic-based susceptibility to bilirubin neurotoxicity and chronic bilirubin encephalopathy (kernicterus) is still poorly understood. Neonatal jaundice affects 60–80% of newborns, and considerable effort goes into preventing this relatively benign condition from escalating into the development of kernicterus making the incidence of this potentially devastating condition very rare in more developed countries. The current understanding of the genetic background of kernicterus is largely comprised of mutations related to alterations of bilirubin production, elimination, or both. Less is known about mutations that may predispose or protect against CNS bilirubin neurotoxicity. The lack of a monogenetic source for this risk of bilirubin neurotoxicity suggests that disease progression is dependent upon an overall decrease in the functionality of one or more essential genetically controlled metabolic pathways. In other words, a “load” is placed on key pathways in the form of multiple genetic variants that combine to create a vulnerable phenotype. The idea of epistatic interactions creating a pathway genetic load (PGL) that affects the response to a specific insult has been previously reported as a PGL score. We hypothesize that the PGL score can be used to investigate whether increased susceptibility to bilirubin-induced CNS damage in neonates is due to a mutational load being placed on key genetic pathways important to the central nervous system's response to bilirubin neurotoxicity. We propose a modification of the PGL score method that replaces the use of a canonical pathway with custom gene lists organized into three tiers with descending levels of evidence combined with the utilization of single nucleotide polymorphism (SNP) causality prediction methods. The PGL score has the potential to explain the genetic background of complex bilirubin induced neurological disorders (BIND) such as kernicterus and could be the key to understanding ranges of outcome severity

  1. A Hypothesis for Using Pathway Genetic Load Analysis for Understanding Complex Outcomes in Bilirubin Encephalopathy.

    PubMed

    Riordan, Sean M; Bittel, Douglas C; Le Pichon, Jean-Baptiste; Gazzin, Silvia; Tiribelli, Claudio; Watchko, Jon F; Wennberg, Richard P; Shapiro, Steven M

    2016-01-01

    Genetic-based susceptibility to bilirubin neurotoxicity and chronic bilirubin encephalopathy (kernicterus) is still poorly understood. Neonatal jaundice affects 60-80% of newborns, and considerable effort goes into preventing this relatively benign condition from escalating into the development of kernicterus making the incidence of this potentially devastating condition very rare in more developed countries. The current understanding of the genetic background of kernicterus is largely comprised of mutations related to alterations of bilirubin production, elimination, or both. Less is known about mutations that may predispose or protect against CNS bilirubin neurotoxicity. The lack of a monogenetic source for this risk of bilirubin neurotoxicity suggests that disease progression is dependent upon an overall decrease in the functionality of one or more essential genetically controlled metabolic pathways. In other words, a "load" is placed on key pathways in the form of multiple genetic variants that combine to create a vulnerable phenotype. The idea of epistatic interactions creating a pathway genetic load (PGL) that affects the response to a specific insult has been previously reported as a PGL score. We hypothesize that the PGL score can be used to investigate whether increased susceptibility to bilirubin-induced CNS damage in neonates is due to a mutational load being placed on key genetic pathways important to the central nervous system's response to bilirubin neurotoxicity. We propose a modification of the PGL score method that replaces the use of a canonical pathway with custom gene lists organized into three tiers with descending levels of evidence combined with the utilization of single nucleotide polymorphism (SNP) causality prediction methods. The PGL score has the potential to explain the genetic background of complex bilirubin induced neurological disorders (BIND) such as kernicterus and could be the key to understanding ranges of outcome severity in

  2. Regression approach to non-invasive determination of bilirubin in neonatal blood

    NASA Astrophysics Data System (ADS)

    Lysenko, S. A.; Kugeiko, M. M.

    2012-07-01

    A statistical ensemble of structural and biophysical parameters of neonatal skin was modeled based on experimental data. Diffuse scattering coefficients of the skin in the visible and infrared regions were calculated by applying a Monte-Carlo method to each realization of the ensemble. The potential accuracy of recovering the bilirubin concentration in dermis (which correlates closely with that in blood) was estimated from spatially resolved spectrometric measurements of diffuse scattering. The possibility to determine noninvasively the bilirubin concentration was shown by measurements of diffuse scattering at λ = 460, 500, and 660 nm at three source-detector separations under conditions of total variability of the skin biophysical parameters.

  3. Amyloid-β peptide binds to cytochrome C oxidase subunit 1.

    PubMed

    Hernandez-Zimbron, Luis Fernando; Luna-Muñoz, Jose; Mena, Raul; Vazquez-Ramirez, Ricardo; Kubli-Garfias, Carlos; Cribbs, David H; Manoutcharian, Karen; Gevorkian, Goar

    2012-01-01

    Extracellular and intraneuronal accumulation of amyloid-beta aggregates has been demonstrated to be involved in the pathogenesis of Alzheimer's disease (AD). However, the precise mechanism of amyloid-beta neurotoxicity is not completely understood. Previous studies suggest that binding of amyloid-beta to a number of macromolecules has deleterious effects on cellular functions. Mitochondria were found to be the target for amyloid-beta, and mitochondrial dysfunction is well documented in AD. In the present study we have shown for the first time that Aβ 1-42 bound to a peptide comprising the amino-terminal region of cytochrome c oxidase subunit 1. Phage clone, selected after screening of a human brain cDNA library expressed on M13 phage and bearing a 61 amino acid fragment of cytochrome c oxidase subunit 1, bound to Aβ 1-42 in ELISA as well as to Aβ aggregates present in AD brain. Aβ 1-42 and cytochrome c oxidase subunit 1 co-immunoprecipitated from mitochondrial fraction of differentiated human neuroblastoma cells. Likewise, molecular dynamics simulation of the cytochrome c oxidase subunit 1 and the Aβ 1-42 peptide complex resulted in a reliable helix-helix interaction, supporting the experimental results. The interaction between Aβ 1-42 and cytochrome c oxidase subunit 1 may explain, in part, the diminished enzymatic activity of respiratory chain complex IV and subsequent neuronal metabolic dysfunction observed in AD.

  4. Amyloid-β Peptide Binds to Cytochrome C Oxidase Subunit 1

    PubMed Central

    Hernandez-Zimbron, Luis Fernando; Luna-Muñoz, Jose; Mena, Raul; Vazquez-Ramirez, Ricardo; Kubli-Garfias, Carlos; Cribbs, David H.; Manoutcharian, Karen; Gevorkian, Goar

    2012-01-01

    Extracellular and intraneuronal accumulation of amyloid-beta aggregates has been demonstrated to be involved in the pathogenesis of Alzheimer's disease (AD). However, the precise mechanism of amyloid-beta neurotoxicity is not completely understood. Previous studies suggest that binding of amyloid-beta to a number of macromolecules has deleterious effects on cellular functions. Mitochondria were found to be the target for amyloid-beta, and mitochondrial dysfunction is well documented in AD. In the present study we have shown for the first time that Aβ 1–42 bound to a peptide comprising the amino-terminal region of cytochrome c oxidase subunit 1. Phage clone, selected after screening of a human brain cDNA library expressed on M13 phage and bearing a 61 amino acid fragment of cytochrome c oxidase subunit 1, bound to Aβ 1–42 in ELISA as well as to Aβ aggregates present in AD brain. Aβ 1–42 and cytochrome c oxidase subunit 1 co-immunoprecipitated from mitochondrial fraction of differentiated human neuroblastoma cells. Likewise, molecular dynamics simulation of the cytochrome c oxidase subunit 1 and the Aβ 1–42 peptide complex resulted in a reliable helix-helix interaction, supporting the experimental results. The interaction between Aβ 1–42 and cytochrome c oxidase subunit 1 may explain, in part, the diminished enzymatic activity of respiratory chain complex IV and subsequent neuronal metabolic dysfunction observed in AD. PMID:22927926

  5. Induction of reactive oxygen species and the potential role of NADPH oxidase in hyperhydricity of garlic plantlets in vitro.

    PubMed

    Tian, Jie; Cheng, Yaqi; Kong, Xiangyu; Liu, Min; Jiang, Fangling; Wu, Zhen

    2017-01-01

    Hyperhydricity is a physiological disorder associated with oxidative stress. Reactive oxygen species (ROS) generation in plants is initiated by various enzymatic sources, including plasma membrane-localized nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, cell wall-bound peroxidase (POD), and apoplastic polyamine oxidase (PAO). The origin of the oxidative burst associated with hyperhydricity remains unknown. To investigate the role of NADPH oxidases, POD, and PAO in ROS production and hyperhydricity, exogenous hydrogen peroxide (H2O2) and inhibitors of each ROS-producing enzyme were applied to explore the mechanism of oxidative stress induction in garlic plantlets in vitro. A concentration of 1.5 mM H2O2 increased endogenous ROS production and hyperhydricity occurrence and enhanced the activities of NADPH oxidases, POD, and PAO. During the entire treatment period, NADPH oxidase activity increased continuously, whereas POD and PAO activities exhibited a transient increase and subsequently declined. Histochemical and cytochemical visualization demonstrated that specific inhibitors of each enzyme effectively suppressed ROS accumulation. Moreover, superoxide anion generation, H2O2 content, and hyperhydric shoot frequency in H2O2-stressed plantlets decreased significantly. The NADPH oxidase inhibitor was the most effective at suppressing superoxide anion production. The results suggested that NADPH oxidases, POD, and PAO were responsible for endogenous ROS induction. NADPH oxidase activation might play a pivotal role in the oxidative burst in garlic plantlets in vitro during hyperhydricity.

  6. Kinetic mechanism of putrescine oxidase from Rhodococcus erythropolis.

    PubMed

    Kopacz, Malgorzata M; Heuts, Dominic P H M; Fraaije, Marco W

    2014-10-01

    Putrescine oxidase from Rhodococcus erythropolis (PuO) is a flavin-containing amine oxidase from the monoamine oxidase family that performs oxidative deamination of aliphatic diamines. In this study we report pre-steady-state kinetic analyses of the enzyme with the use of single- and double-mixing stopped-flow spectroscopy and putrescine as a substrate. During the fast and irreversible reductive half-reaction no radical intermediates were observed, suggesting a direct hydride transfer from the substrate to the FAD. The rate constant of flavin reoxidation depends on the ligand binding; when the imine product was bound to the enzyme the rate constant was higher than with free enzyme species. Similar results were obtained with product-mimicking ligands and this indicates that a ternary complex is formed during catalysis. The obtained kinetic data were used together with steady-state rate equations derived for ping-pong, ordered sequential and bifurcated mechanisms to explore which mechanism is operative. The integrated analysis revealed that PuO employs a bifurcated mechanism due to comparable rate constants of product release from the reduced enzyme and reoxidation of the reduced enzyme-product complex.

  7. Ferricytochrome c protects mitochondrial cytochrome c oxidase against hydrogen peroxide-induced oxidative damage.

    PubMed

    Sedlák, Erik; Fabian, Marian; Robinson, Neal C; Musatov, Andrej

    2010-11-30

    An excess of ferricytochrome c protects purified mitochondrial cytochrome c oxidase and bound cardiolipin from hydrogen peroxide-induced oxidative modification. All of the peroxide-induced changes within cytochrome c oxidase, such as oxidation of Trp(19,IV) and Trp(48,VIIc), partial dissociation of subunits VIa and VIIa, and generation of cardiolipin hydroperoxide, no longer take place in the presence of ferricytochrome c. Furthermore, ferricytochrome c suppresses the yield of H(2)O(2)-induced free radical detectable by electron paramagnetic resonance spectroscopy within cytochrome c oxidase. These protective effects are based on two mechanisms. The first involves the peroxidase/catalase-like activity of ferricytochrome c, which results in the decomposition of H(2)O(2), with the apparent bimolecular rate constant of 5.1±1.0M(-1)s(-1). Although this value is lower than the rate constant of a specialized peroxidase, the activity is sufficient to eliminate H(2)O(2)-induced damage to cytochrome c oxidase in the presence of an excess of ferricytochrome c. The second mechanism involves ferricytochrome c-induced quenching of free radicals generated within cytochrome c oxidase. These results suggest that ferricytochrome c may have an important role in protection of cytochrome c oxidase and consequently the mitochondrion against oxidative damage.

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

    PubMed Central

    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

    2016-01-01

    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. PMID:27484402

  9. Effects of special blue fluorescent light on hepatic mixed-function oxidase activity in the rat

    SciTech Connect

    Davis, D.R.; Yeary, R.A.; Randall, G.

    1981-01-01

    Phototherapy has been widely used in the treatment of neonatal hyperbilirubinemia. Recent reports, however, have indicated that fluorescent light may be toxic and mutagenic to mammalian cells. these findings suggest possible long-term side effects with the use of phototherapy. This study was undertaken to determine the effects of phototherapy on hepatic microsomal enzyme activity. The exposure of Sprague-Dawley and Gunn rats to special blue fluorescent light at an average irradiance of 1,200 microW/cm2 resulted in no significant changes in liver microsomal enzyme activity for aniline hydroxylase, p-nitroanisole-O-demethylase, ethylmorphine-N-demethylase, cytochrome c reductase or the quantity of cytochrome P-450. A significant decrease in aniline hydroxylase and p-nitroanisole-O-demethylase activity was observed when liver microsomes were exposed in vitro to special blue fluorescent light. Photoactivated bilirubin did not effect the activity of the mixed-function oxidase enzymes measured under the conditions of this study.

  10. Monoamine oxidase inactivation: from pathophysiology to therapeutics

    PubMed Central

    Bortolato, Marco; Chen, Kevin; Shih, Jean C

    2008-01-01

    Monoamine oxidases (MAOs) A and B are mitochondrial bound isoenzymes which catalyze the oxidative deamination of dietary amines and monoamine neurotransmitters, such as serotonin, norepinephrine, dopamine, β-phenylethylamine and other trace amines. The rapid degradation of these molecules ensures the proper functioning of synaptic neurotransmission and is critically important for the regulation of emotional behaviors and other brain functions. The byproducts of MAO-mediated reactions include several chemical species with neurotoxic potential, such as hydrogen peroxide, ammonia and aldehydes. As a consequence, it is widely speculated that prolonged excessive activity of these enzymes may be conducive to mitochondrial damages and neurodegenerative disturbances. In keeping with these premises, the development of MAO inhibitors has led to important breakthroughs in the therapy of several neuropsychiatric disorders, ranging from mood disorders to Parkinson’s disease. Furthermore, the characterization of MAO knockout (KO) mice has revealed that the inactivation of this enzyme produces a number of functional and behavioral alterations, some of which may be harnessed for therapeutic aims. In this article, we discuss the intriguing hypothesis that the attenuation of the oxidative stress induced by the inactivation of either MAO isoform may contribute to both antidepressant and antiparkinsonian actions of MAO inhibitors. This possibility further highlights MAO inactivation as a rich source of novel avenues in the treatment of mental disorders. PMID:18652859

  11. [Alternative oxidase - never ending story].

    PubMed

    Szal, Bożena; Rychter, Anna M

    2016-01-01

    Investigations of plant cyanide resistant respiration lead to the discovery in mitochondrial respiratory chain of the second terminal oxidase, alternative oxidase (AOX). AOX transfers electrons from reduced ubiquinone to oxygen omitting two coupling places thus lowering energetic efficiency of respiration. The presence of AOX was shown in all plants and also in some fungi, mollusca and protista. In termogenic plants the activity of AOX is connected with heat production. In other organisms AOX activity is important for maintaining metabolic homeostasis (carbon metabolism, cell redox state and energy demand) and ROS homeostasis. In this article structure of plant AOX protein and the regulation on molecular levels was described. Possible role of AOX as stress marker was pointed and the possibility of using AOX in human gene therapy was discussed.

  12. Lysyl oxidase in cancer research.

    PubMed

    Perryman, Lara; Erler, Janine T

    2014-01-01

    Metastasis is the main reason for cancer-associated deaths and therapies are desperately needed to target the progression of cancer. Lysyl oxidase (LOX) plays a pivotal role in cancer progression, including metastasis, and is therefore is an attractive therapeutic target. In this review we will breakdown the process of cancer progression and the various roles that LOX plays has in the advancement of cancer. We will highlight why LOX is an exciting therapeutic target for the future.

  13. The terminal oxidases of Paracoccus denitrificans.

    PubMed

    de Gier, J W; Lübben, M; Reijnders, W N; Tipker, C A; Slotboom, D J; van Spanning, R J; Stouthamer, A H; van der Oost, J

    1994-07-01

    Three distinct types of terminal oxidases participate in the aerobic respiratory pathways of Paracoccus denitrificans. Two alternative genes encoding subunit I of the aa3-type cytochrome c oxidase have been isolated before, namely ctaDI and ctaDII. Each of these genes can be expressed separately to complement a double mutant (delta ctaDI, delta ctaDII), indicating that they are isoforms of subunit I of the aa3-type oxidase. The genomic locus of a quinol oxidase has been isolated: cyoABC. This protohaem-containing oxidase, called cytochrome bb3, is the only quinol oxidase expressed under the conditions used. In a triple oxidase mutant (delta ctaDI, delta ctaDII, cyoB::KmR) an alternative cytochrome c oxidase has been characterized; this cbb3-type oxidase has been partially purified. Both cytochrome aa3 and cytochrome bb3 are redox-driven proton pumps. The proton-pumping capacity of cytochrome cbb3 has been analysed; arguments for and against the active transport of protons by this novel oxidase complex are discussed.

  14. Hexanediamine functionalized poly (glycidyl methacrylate-co-N-vinylpyrrolidone) particles for bilirubin removal.

    PubMed

    Jiang, Xing; Zhou, Dongxu; Huang, Xueliang; Zhao, Weifeng; Zhao, Changsheng

    2017-10-15

    In this study, we provided a facile method to prepare adsorbents with high content of amino groups for bilirubin removal. Poly (glycidyl methacrylate-co-N-vinylpyrrolidone) particle adsorbents were prepared through free radical solution copolymerization followed by a phase inversion technique. Amino groups were further introduced onto the particles by grafting 1,6-hexanediamine molecules. The porosity and specific surface area of the functional particles were 92.9% and 11.8m(2)/g, respectively. Flourier transform infrared spectroscopy and elemental analysis confirmed the successful functionalization of polymeric particles. The cross-linker content and N-vinylpyrrolidone ratios had significant influence on the pore structure of the polymeric particles, as observed by scanning electron microscopy. Batch adsorption experiments were performed to verify bilirubin adsorption behavior of the particles, and a particle column was fabricated to further study the bilirubin removal. The particles exhibited good adsorption capacity of bilirubin without procoagulant activity, and had great potential to be used in hemoperfusion. The study opens a new route to fabricate functional polymer adsorbents. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Transcutaneous bilirubin measurement at the time of hospital discharge in a multiethnic newborn population

    PubMed Central

    Campbell, Douglas M; Danayan, Karoon C; McGovern, Valleverdina; Cheema, Sohail; Stade, Brenda; Sgro, Michael

    2011-01-01

    BACKGROUND: Severe neonatal hyperbilirubinemia continues to occur in healthy newborns. Recent guidelines have supported using transcutaneous devices in estimating bilirubin levels. Previous studies using these devices are limited. METHODS: Newborns requiring serum bilirubin level measurements before hospital discharge were recruited prospectively. The agreement between a transcutaneous bilirubin (TCB) and total serum bilirubin (TSB) level was assessed. Sensitivity analysis was conducted. RESULTS: A total of 430 infants were enrolled. Correlation between the values was high (Pearson’s correlation coefficient 0.83; Lin’s concordance coefficient 0.81 [95% CI 0.77 to 0.84]; P<0.001). The mean (± SD) TSB level was 194±60 μmol/L. The TCB measurement tended to overestimate the value (mean difference 12.7), with wide 95% limits of agreement (−52 μmol/L to 77 μmol/L). Sensitivity and specificity analysis of TCB values allowed estimation of clinically important TSB levels. CONCLUSIONS: The TCB correlated, but was imprecise in predicting TSB. TCB values can be used at the time of discharge to safely plan care for jaundiced infants if the limits of agreement are considered and clinical judgment is maintained. PMID:22379376

  16. 21 CFR 862.1110 - Bilirubin (total or direct) test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bilirubin (total or direct) test system. 862.1110 Section 862.1110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test...

  17. 21 CFR 862.1115 - Urinary bilirubin and its conjugates (nonquantitative) test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Urinary bilirubin and its conjugates (nonquantitative) test system. 862.1115 Section 862.1115 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES...

  18. 21 CFR 862.1113 - Bilirubin (total and unbound) in the neonate test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bilirubin (total and unbound) in the neonate test system. 862.1113 Section 862.1113 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical...

  19. 21 CFR 862.1110 - Bilirubin (total or direct) test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Bilirubin (total or direct) test system. 862.1110 Section 862.1110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test...

  20. 21 CFR 862.1110 - Bilirubin (total or direct) test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Bilirubin (total or direct) test system. 862.1110 Section 862.1110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test...

  1. 21 CFR 862.1110 - Bilirubin (total or direct) test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Bilirubin (total or direct) test system. 862.1110 Section 862.1110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test...

  2. 21 CFR 862.1110 - Bilirubin (total or direct) test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Bilirubin (total or direct) test system. 862.1110 Section 862.1110 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test...

  3. Deracemization of bilirubin as the marker of the chirality of micellar aggregates.

    PubMed

    Sorrenti, Alessandro; Altieri, Barbara; Ceccacci, Francesca; Di Profio, Pietro; Germani, Raimondo; Giansanti, Luisa; Savelli, Gianfranco; Mancini, Giovanna

    2012-01-01

    The deracemization of bilirubin in micellar aggregates of structurally correlated chiral surfactants was studied by circular dichroism experiments and exploited as the marker of the expression of chirality of the aggregates. The obtained results suggest that the hydrophobic interactions control the transfer of chirality from the monomers to the aggregates, and that different regions of the same aggregate might feature opposite enantiorecognition capabilities.

  4. Immune response to lentiviral bilirubin UDP-glucuronosyltransferase gene transfer in fetal and neonatal rats.

    PubMed

    Seppen, J; van Til, N P; van der Rijt, R; Hiralall, J K; Kunne, C; Elferink, R P J Oude

    2006-04-01

    Gene therapy for inherited disorders might cause an immune response to the therapeutic protein. A solution would be to introduce the gene in the fetal or neonatal period, which should lead to tolerization. Lentiviral vectors mediate long-term gene expression, and are well suited for gene therapy early in development. A model for fetal or neonatal gene therapy is the inherited disorder of bilirubin metabolism, Crigler-Najjar disease (CN). The absence of bilirubin UDP-glucoronyltransferase (UGT1A1) activity in CN patients causes high serum levels of unconjugated bilirubin and brain damage in infancy. CN is attractive for the development of gene therapy because the mutant Gunn rat closely mimics the human disease. Injection of UGT1A1 lentiviral vectors corrected the hyperbilirubinemia for more than a year in rats injected as fetuses and for up to 18 weeks in rats injected the day of birth. UGT1A1 gene transfer was confirmed by the presence of bilirubin glucuronides in bile. All animals injected with UGT1A1 lentiviral vectors developed antibodies to UGT1A1. Animals injected with green fluorescent protein (GFP) lentiviral vectors did not develop antibodies to GFP. Our results indicate that fetal and neonatal gene therapy with immunogenic proteins such as UGT1A1 does not necessarily lead to tolerization.

  5. Toxic epidermal necrolysis with severe hyperbilirubinemia: complete re-epithelialization after bilirubin reduction therapies.

    PubMed

    Kamada, Noriaki; Yoneyama, Kei; Togawa, Yaei; Suehiro, Keisuke; Shinkai, Hiroshi; Yokota, Masaya; Matsuda, Kenichi; Oda, Shigeto; Hirasawa, Hiroyuki; Matsue, Hiroyuki

    2010-06-01

    Toxic epidermal necrolysis is a life-threatening skin disorder, and its mortality rate is estimated to be approximately 20-30%. It is characterized that more than 30% of the skin surface is eroded, however, skin lesions are usually re-epithelialized within 2-3 weeks. Previously, we reported a fatal case of toxic epidermal necrolysis with hyperbilirubinemia, and more than 60% of body surface areas had been eroded for 9 weeks. For the reason of delayed re-epithelialization, we hypothesized that hyperbilirubinemia was the culprit because bilirubin damaged cultured keratinocytes in vitro. In this case, we had an opportunity to treat another case of toxic epidermal necrolysis with severe hyperbilirubinemia. In order to reduce serum bilirubin levels, we performed bilirubin adsorption therapies, and skin lesions were successfully re-epithelialized within 4 weeks. Though further studies are required, we considered that bilirubin adsorption therapies are worth trying for toxic epidermal necrolysis with hyperbilirubinemia, especially for the cases suffering from delayed re-epithelialization.

  6. Relationship between total bilirubin, endothelial function, inflammation and oxidative stress in HIV-infected adults on stable antiretroviral therapy

    PubMed Central

    Hileman, Corrilynn O.; Longenecker, Chris T.; Carman, Teresa L.; Milne, Ginger L.; Labbato, Danielle E.; Storer, Norma J.; White, Cynthia A.; McComsey, Grace A.

    2012-01-01

    Objective Enhanced inflammation is evident in HIV, even with virologic suppression. Outside HIV, studies show an independent association between higher total bilirubin and better endothelial function as well as lower prevalence of coronary heart disease possibly due to the anti-inflammatory and antioxidant effect of bilirubin. Methods A cross-sectional study was performed in HIV-1 infected adults on stable antiretroviral therapy (ART) to determine if a relationship exists between total bilirubin and endothelial function (flow mediated dilation (FMD) of the brachial artery), inflammation (interleukin-6 (IL-6), soluble tumor necrosis factor receptors, C-reactive protein, adhesion molecules), coagulation markers (fibrinogen and D-Dimer) and oxidative stress (F2-Isoprostanes). Endpoints were compared based on total bilirubin levels and atazanavir status using distributionally-appropriate, two-sample tests. Correlation coefficients were determined between total bilirubin and end points. Linear regression was used to model the relationship between total bilirubin (and atazanavir status) and FMD. Results 98 adults were included. Total bilirubin was higher in atazanavir group (median (IQR) 1.8 (1.1–2.6) vs. 0.6 (0.4–1.4) mg/dL; p<0.01) as was insulin, HOMA-IR and fibrinogen. Total bilirubin was positively correlated with fibrinogen and was not correlated with other outcomes. After adjustment, neither total bilirubin nor atazanavir status was associated with FMD. Conclusions In virologically-suppressed, HIV-infected adults on stable ART, neither total bilirubin nor atazanavir use was associated with improved endothelial function as measured by FMD, inflammation or oxidative stress as measured by biomarkers. PMID:22624591

  7. Microchip capillary electrophoresis for frontal analysis of free bilirubin and study of its interaction with human serum albumin.

    PubMed

    Nie, Zhou; Fung, Ying Sing

    2008-05-01

    To meet the need for bedside monitoring of free bilirubin for neonates under critical conditions, a microfluidic chip was fabricated and tested for its coupling with CE/frontal analysis (FA) to determine free bilirubin and study of its binding interaction with HSA, which regulated its concentration in plasma. The poly(methyl methacrylate) (PMMA) multichannel chip was fabricated by CO2 laser ablation and bonded with a fused-silica separation capillary for CE/FA separation with UV detection. The chip was designed to allow a complete assay of four electrophoretic runs using preconditioned channels to speed up the determination of free bilirubin and to deliver quick results for bedside monitoring. Under optimized conditions, the linear working range for free bilirubin was from 10 to 200 micromol with RSDs from 2.1 to 5.0% for n=3, and the LOD at 9 micromol for S/N=3. From a binding study between bilirubin and HSA under FA condition, the second binding constant for bilirubin-HSA was determined as 1.07x10(5) L/mol and the number of binding sites per HSA as 3.46. The results enabled the calculation of free bilirubin for jaundiced infants based on the clinically significant level of total bilirubin, producing a range of 118.3-119.4 micromol/L. The developed method is shown to meet the clinical requirement with additional margin of protection to detect the early rising level of free bilirubin prior to jaundice condition. The low-cost microchip CE/FA device is shown to produce quick results with high potential to deliver a suitable bed-side monitoring method for bilirubin management in neonates.

  8. Crystal Structures of Intermediates in the Nitroalkane Oxidase Reaction

    SciTech Connect

    Heroux, A.; Bozinovski, D; Valley, M; Fitzpatrick, P; Orville, A

    2009-01-01

    The flavoenzyme nitroalkane oxidase is a member of the acyl-CoA dehydrogenase superfamily. Nitroalkane oxidase catalyzes the oxidation of neutral nitroalkanes to nitrite and the corresponding aldehydes or ketones. Crystal structures to 2.2 {angstrom} resolution or better of enzyme complexes with bound substrates and of a trapped substrate-flavin adduct are described. The D402N enzyme has no detectable activity with neutral nitroalkanes. The structure of the D402N enzyme crystallized in the presence of 1-nitrohexane or 1-nitrooctane shows the presence of the substrate in the binding site. The aliphatic chain of the substrate extends into a tunnel leading to the enzyme surface. The oxygens of the substrate nitro group interact both with amino acid residues and with the 2'-hydroxyl of the FAD. When nitroalkane oxidase oxidizes nitroalkanes in the presence of cyanide, an electrophilic flavin imine intermediate can be trapped (Valley, M. P., Tichy, S. E., and Fitzpatrick, P. F. (2005) J. Am. Chem. Soc. 127, 2062-2066). The structure of the enzyme trapped with cyanide during oxidation of 1-nitrohexane shows the presence of the modified flavin. A continuous hydrogen bond network connects the nitrogen of the CN-hexyl-FAD through the FAD 2'-hydroxyl to a chain of water molecules extending to the protein surface. Together, our complementary approaches provide strong evidence that the flavin cofactor is in the appropriate oxidation state and correlates well with the putative intermediate state observed within each of the crystal structures. Consequently, these results provide important structural descriptions of several steps along the nitroalkane oxidase reaction cycle.

  9. Modification of continuous venovenous hemodiafiltration with single-pass albumin dialysate allows for removal of serum bilirubin.

    PubMed

    Chawla, Lakhmir S; Georgescu, Florin; Abell, Bruce; Seneff, Michael G; Kimmel, Paul L

    2005-03-01

    A 53-year-old woman was admitted to the hospital with ischemic colitis and underwent a subtotal colectomy. She developed acute renal failure, severe hyperbilirubinemia, and intense pruritus resistant to medical treatment. Extracorporeal albumin dialysis using a Molecular Adsorbent Recirculating System (MARS; Gambro Co, Lund, Sweden) has been used to treat liver failure and reduce total serum bilirubin (SB) levels. A trial of extracorporeal albumin dialysis with continuous renal replacement therapy (RRT) was instituted to achieve net removal of SB. A 25% albumin solution was mixed with conventional dialysate to yield a dialysate concentration of 1.85% or 5.0% albumin. The patient underwent 2 continuous RRT sessions using extracorporeal albumin dialysis (1.85% and 5.0% albumin dialysate). Pretreatment and posttreatment SB levels were determined, and total bilirubin concentration (TB) also was measured in each of the collection bags during conventional and albumin dialysis. Pretreatment and posttreatment SB levels were 50.4 mg/dL (862 micromol/L) and 39.0 mg/dL (667 micromol/L) with 1.85% albumin dialysate and 47.1 mg/dL (805 micromol/L) and 39.7 mg/dL (679 micromol/L) with 5.0% albumin dialysate, respectively. The collected dialysate TB level was 0.3 mg/dL (5 micromol/L) during nonalbumin RRT and increased to 1.37 +/- 0.06 mg/dL (23 +/- 1 micromol/L) with 1.85% albumin dialysis. The collected dialysate fluid TB level was 0.3 mg/dL (5 micromol/L) during the nonalbumin RRT and increased to 1.38 +/- 0.15 mg/dL (24 +/- 3 micromol/L) during 5.0% albumin RRT. Single-pass albumin dialysis with continuous RRT cleared SB better than standard continuous RRT. Single-pass albumin dialysis with continuous RRT is feasible and may be a viable alternative in centers that do not have access to MARS therapy. This modality merits additional evaluation for its efficacy in clearing albumin-bound serum toxins.

  10. Simple, Reagentless Quantification of Total Bilirubin in Blood Via Microfluidic Phototreatment and Image Analysis.

    PubMed

    Thompson, Brandon L; Wyckoff, Sarah L; Haverstick, Doris M; Landers, James P

    2017-03-07

    Total bilirubin (T-Bil) is an important clinical diagnostic marker that is measured frequently by physicians to assist in the diagnosis, treatment, and monitoring of multiple medical conditions. The work demonstrated here utilizes the 48-year-old mechanism of phototherapy that is commonly implemented in the treatment of infants with exaggerated physiologic and pathologic jaundice but adapts it to the microfluidic level for the ultimate purpose of total bilirubin quantitation. After acquisition of a small volume of blood (<10 μL) and through subsequent separation (plasma + red blood cells), a 3 μL plasma sample was imaged by a portable scanner and analyzed through a custom algorithm for color intensity. After blue light irradiation for 10 min at 470 nm, the sample was reimaged and analyzed. The resulting intensities obtained pre- and postimaging (clearly observed through a color change from yellow to clear) were then utilized to calculate the total bilirubin concentration. A total of 34 blood samples were analyzed with microfluidic photo treatment-image analysis (μPIA) and were found to have a Deming-regression slope of 0.97 (R(2) = 0.960) when compared to the total bilirubin values determined in the clinical laboratory. We demonstrate the implementation of a centrifugal microdevice fabricated through the Print, Cut, and Laminate (PCL) method that accepts eight whole blood samples and provides the capabilities to not only quantitate total bilirubin (Deming-regression slope of 0.95, R(2) = 0.990) but allow future integration with excess plasma sufficient for additional downstream clinical assays. This work will highlight the inexpensive nature of the analysis (absence of caustic, viscous, or additional reagents), the simplicity (does not require any chemical reactions), speed (sample-to-answer in <15 min), insusceptibility to biofouling (no protein matrix effects, hemoglobin interferences, and minimized turbidity), low volume plasma requirement (3 μL), and the

  11. The Role of Bilirubin in Diabetes, Metabolic Syndrome, and Cardiovascular Diseases

    PubMed Central

    Vítek, Libor

    2012-01-01

    Bilirubin belongs to a phylogenetically old superfamily of tetrapyrrolic compounds, which have multiple biological functions. Although for decades bilirubin was believed to be only a waste product of the heme catabolic pathway at best, and a potentially toxic compound at worst; recent data has convincingly demonstrated that mildly elevated serum bilirubin levels are strongly associated with a lower prevalence of oxidative stress-mediated diseases. Indeed, serum bilirubin has been consistently shown to be negatively correlated to cardiovascular diseases (CVD), as well as to CVD-related diseases and risk factors such as arterial hypertension, diabetes mellitus, metabolic syndrome, and obesity. In addition, the clinical data are strongly supported by evidence arising from both in vitro and in vivo experimental studies. This data not only shows the protective effects of bilirubin per se; but additionally, of other products of the heme catabolic pathway such as biliverdin and carbon monoxide, as well as its key enzymes (heme oxygenase and biliverdin reductase); thus, further underlining the biological impacts of this pathway. In this review, detailed information on the experimental and clinical evidence between the heme catabolic pathway and CVD, and those related diseases such as diabetes, metabolic syndrome, and obesity is provided. All of these pathological conditions represent an important threat to human civilization, being the major killers in developed countries, with a steadily increasing prevalence. Thus, it is extremely important to search for novel markers of these diseases, as well as for novel therapeutic modalities to reverse this unfavorable situation. The heme catabolic pathway seems to fulfill the criteria for both diagnostic purposes as well as for potential therapeutical interventions. PMID:22493581

  12. Measurement of unbound bilirubin by the peroxidase test using Zone Fluidics.

    PubMed

    Ahlfors, Charles E; Marshall, Graham D; Wolcott, Duane K; Olson, Don C; Van Overmeire, Bart

    2006-03-01

    Measuring plasma unbound bilirubin concentration by the peroxidase test is useful in the management of jaundiced newborns. However, the commercially available peroxidase technology is manual, and the unbound bilirubin may be seriously underestimated at the 42-fold sample dilution and single peroxidase concentration used. We investigated improving the test by adapting it to Zone Fluidics, which is a system for automating reactant handling that requires small sample volumes and dilution. A computer-directed Zone Fluidics system was constructed using small diameter tubing to connect in series a water-surfactant reservoir, a bi-directional pump, a multiport selection valve to which peroxidase test reactants (45 mul of sample) are attached with one port open to air, and a spectrophotometer flow cell. Test reactants and air are sequentially aspirated through the valve into the tubing connecting the pump and valve to form a reactant "zone" surrounded by air. The zone is advanced to the spectrophotometer flow cell where total and unbound bilirubin are determined (37 degrees C) from the absorbance at 460 nm at a 2-fold sample dilution and 4 peroxidase concentrations. Imprecision was assessed in artificial controls and newborn plasma. Plasma results were compared with those obtained using the commercial method. The CV for unbound bilirubin in the various controls ranged from 11% to 38% (within day) and 12% to 27% (between days). Triplicate CV measurements for newborn plasma measurements ranged from 0.6% to 31% (mean 11%, n=47). Mean unbound bilirubin by Zone Fluidics was 5-fold higher than that by the commercial method. Zone Fluidics can be used to automate the peroxidase test and overcome many of the limitations of the commercially available peroxidase technology.

  13. Lower Serum Bilirubin and Uric Acid Concentrations in Patients with Parkinson's Disease in China.

    PubMed

    Qin, Xiao-Ling; Zhang, Qing-Shan; Sun, Li; Hao, Meng-Wei; Hu, Zhao-Ting

    2015-05-01

    The objective of the study is to investigate the correlation between bilirubin and uric acid (UA) concentrations and symptoms of Parkinson's disease (PD) in Chinese population. A total of 425 PD patients and 460 controls were included in the current study. Patients were diagnosed by a neurologist and assessed using the Hoehn & Yahr (H&Y) scale. Venous blood samples were collected, and bilirubin and UA concentrations were analyzed. Compared to controls, indirect bilirubin (IBIL) and UA concentrations were lower in PD patients (P IBIL = 0.015, P UA = 0.000). Serum IBIL in different age subgroups and H&Y stage subgroups were also lower compared to the control group (P IBIL = 0.000, P UA = 0.000) but were not significantly different among these subgroups. Females in the control group had significantly lower serum IBIL and UA concentrations than males (P IBIL = 0.000, P UA = 0.000) and the PD group (P IBIL = 0.027, P UA = 0.000). In early PD (patients with <2-year medical history and no treatment), serum IBIL and UA concentrations were also lower than the controls (P IBIL = 0.013, P UA = 0.000). Although IBIL concentration was positively correlated with UA concentration in controls (R IBIL = 0.229, P IBIL = 0.004), this positive association was not observed in the PD group (R IBIL = -0.032, P IBIL = 0.724). Decreased levels of serum IBIL and UA were observed in PD patients. It is possible that individuals with decreased serum bilirubin and UA concentrations lack the endogenous defense system to prevent peroxynitrite and other free radicals from damaging and destroying dopaminergic cells in the substantia nigra. Our results provide a basis for further investigation into the role of bilirubin in PD.

  14. Selective nonenzymatic bilirubin detection in blood samples using a Nafion/Mn-Cu sensor.

    PubMed

    Noh, Hui-Bog; Won, Mi-Sook; Shim, Yoon-Bo

    2014-11-15

    The specific detection of biological organics without the use of an enzyme is challenging, and it is crucial for analytical and clinical chemistry. We report specific nonenzymatic bilirubin detection through the catalytic oxidation of bilirubin molecule on the Nafion/Mn-Cu surface. The catalytic ability, true surface area, morphology, crystallinity, composition, and oxidation state of the sensor surface were assessed using voltammetry, coulometry, XPS, XRD, Brunauer-Emmett-Teller (BET), SEM, EDXS, and TOF-SIMS experiments. The results showed that the surface was composed of microporous Mn-Cu bimetallic crystal in flake shape with a large BET surface area (3.635 m(2)g(-1)), where the surface area and crystallinity mainly affected the sensor performance. Product analysis of the catalytic reaction on the sensor probe revealed a specific two-electron oxidation of dipyrromethane moiety to dipyrromethene in the bilirubin molecule. Experimental variables affecting the analysis of bilirubin were optimized in terms of probe composition, temperature, pH, and potential. At the optimized condition, the dynamic range was between 1.2 μM and 0.42 mM, which yielded the equation of ΔI (μA)=(1.03 ± 0.72)+(457.0 ± 4.03) [C] (mM) with 0.999 of correlation coefficient, and the detection limit was 25.0 ± 1.8 nM (n=5, k=3). The stability test, interference effects, and analysis of real clinical samples, human whole blood and certified serum samples were demonstrated to confirm the reliability of the proposed bilirubin sensor.

  15. Increased bilirubin levels in neonates after induction of labour by intravenous prostaglandin E2 or oxytocin.

    PubMed

    Calder, A A; Ounsted, M K; Moar, V A; Turnbull, A C

    1974-12-07

    4 groups of 30 primigravidas and their infants were studied prospectively. No patient with rhesus incompatibility was included in the study. The 4 groups went into labor in the following ways: 1) induced by intravenous oxytocin; 2) induced by intravenous prostagladin (PG)E2; 3) induced by extraamniotic PGE2; and 4) spontaneous labor. Mean infant bilirubin levels on day 5 were significantly higher (p.005 and p.025 respectively) for the 1st 2 groups than for the spontaneous group. Levels for the group whose labor was induced with extraamniotic PGE2 infusion were not significantly different from those in the 1st 2 groups or the spontaneous group. The mean serum-bilirubin level was significantly lower (p.025) after caesarean section than after assisted vaginal delivery. Serum-bilirubin levels were not affected by previous maternal use of oral contraceptives, maternal smoking, or methods of infant feeding. Serum bilirubin levels below 10 mg/100 ml. are considered within the normal phsyiological limits during the neonatal period. Measured by this criteria, 14, 10, 9, and 6 babies in groups 1-4 respectively had abnormally high levels. The difference between groups 1 and 4 was significant at the p.05 level. Mean Apgar scores were significantly lower for the babies whose mothers had induced delivery with extraamniotic PGE2 infusion. These results suggest that the observed hyperbilirubinemia may be due to interruption of pregnancy rather than to any direct drug effect. There is no evidence to suggest that such high bilirubin levels are harmful to the child in the long run.

  16. Red clover polyphenol oxidase and lipid metabolism.

    PubMed

    Van Ranst, G; Lee, M R F; Fievez, V

    2011-02-01

    Increasing the polyunsaturated fatty acid (PUFA) composition of milk is acknowledged to be of benefit to consumer health. Despite the high PUFA content of forages, milk fat contains only about 3% of PUFA and only about 0.5% of n-3 fatty acids. This is mainly due to intensive lipid metabolism in the rumen (lipolysis and biohydrogenation) and during conservation (lipolysis and oxidation) such as drying (hay) and ensiling (silage). In red clover, polyphenol oxidase (PPO) has been suggested to protect lipids against degradation, both in the silage as well as in the rumen, leading to a higher output of PUFA in ruminant products (meat and milk). PPO mediates the oxidation of phenols and diphenols to quinones, which will readily react with nucleophilic binding sites. Such binding sites can be found on proteins, resulting in the formation of protein-bound phenols. This review summarizes the different methods that have been used to assess PPO activity in red clover, and an overview on the current understanding of PPO activity and activation in red clover. Knowledge on these aspects is of major importance to fully harness PPO's lipid-protecting role. Furthermore, we review the studies that evidence PPO-mediated lipid protection and discuss its possible importance in lab-scale silages and further in an in vitro rumen system. It is demonstrated that high (induction of) PPO activity can lead to lower lipolysis in the silage and lower biohydrogenation in the rumen. There are three hypotheses on its working mechanism: (i) protein-bound phenols could directly bind to enzymes (e.g. lipases) as such inhibiting them; (ii) binding of quinones in and between proteins embedded in a lipid membrane (e.g. in the chloroplast) could lead to encapsulation of the lipids; (iii) direct binding of quinones to nucleophilic sites in polar lipids also could lead to protection. There is no exclusive evidence on which mechanism is most important, although there are strong indications that only lipid

  17. Physical Uncertainty Bounds (PUB)

    SciTech Connect

    Vaughan, Diane Elizabeth; Preston, Dean L.

    2015-03-19

    This paper introduces and motivates the need for a new methodology for determining upper bounds on the uncertainties in simulations of engineered systems due to limited fidelity in the composite continuum-level physics models needed to simulate the systems. We show that traditional uncertainty quantification methods provide, at best, a lower bound on this uncertainty. We propose to obtain bounds on the simulation uncertainties by first determining bounds on the physical quantities or processes relevant to system performance. By bounding these physics processes, as opposed to carrying out statistical analyses of the parameter sets of specific physics models or simply switching out the available physics models, one can obtain upper bounds on the uncertainties in simulated quantities of interest.

  18. Diphosphatidylglycerol is required for optimal activity of beef heart cytochrome c oxidase.

    PubMed Central

    Vik, S B; Georgevich, G; Capaldi, R A

    1981-01-01

    Isolated beef heart cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1) contains four or five molecules of tightly bound diphosphatidylglycerol per monomer (2-heme complex). This lipid could be removed in part, or wholly, by mixing the enzyme with high concentrations of Triton X-100 and then centrifuging the mixture through a glycerol gradient equilibrated in the same detergent. Cytochrome c oxidase retaining three or more diphosphatidylglycerol molecules per monomer was fully active when assayed in 1-oleoyl lysophosphatidylcholine. Upon removal of one or more of these diphosphatidylglycerols, enzymic activity was lost. Full activation could be obtained by adding diphosphatidylglycerol to the assay mixture along with lysophosphatidylcholine but not by adding phosphatidylcholine or phosphatidylethanolamine. Direct binding experiments, kinetic studies, and previous work using arylazidocytochrome c derivatives [Bisson, R., Jacobs, B. & Capaldi, R. A. (1980) Biochemistry 10, 4173-4178], indicate that diphosphatidylglycerol is involved in binding of substrate cytochrome c to cytochrome c oxidase. PMID:6262802

  19. [Hydrazine derivative modification of the activity of brain mitochondrial monoamine oxidases].

    PubMed

    Kalninia, I E; Baumanas, E A; Kaĭrane, Ch B; Gorkin, V Z

    1981-01-01

    Treatment of bovine brain stem mitochondria with hydrazine derivatives, which inhibited the monoamine oxidase activity (substrate: 5-hydroxytryptamine), was accompanied by appearance of the properties to deaminate histamine and cadaverine at a high rate. The same phenomenon was observed in vivo after treatment of mice with the hydrazine derivatives. The dramatic increase in histamine deaminating activity in brain was accompanied by a decrease in the tissue concentration of histamine. The hydrazine derivatives are considered as prooxidants stimulating via a free-radical mechanism lipid peroxidation in methyloleate solutions and in biomembranes (ref. 5) and causing qualitative alteration (transformation) in catalytic properties of monoamine oxidases of the tyre A, which acquire the histamine deaminating activity. A certain correlation was noted between the prooxidant effect of the hydrazine derivatives and the modification of catalytic properties of the membrane bound monoamine oxidases of brain mitochondria in vitro and in vivo.

  20. Bilirubin clearance and antioxidant activities of ethanol extract of Phyllanthus amarus root in phenylhydrazine-induced neonatal jaundice in mice.

    PubMed

    Maity, Soumya; Nag, Nivedita; Chatterjee, Suchandra; Adhikari, Soumyakanti; Mazumder, Santasree

    2013-09-01

    The ability of ethanol extract of Phyllanthus amarus root (EEPA) to decrease bilirubin level and oxidative stress in phenylhydrazine-induced neonatal jaundice in mice was investigated. Administration of phenylhydrazine (75 mg/kg b.w.) significantly elevated total and unconjugated serum bilirubin level compared to control mice. EEPA (5, 10, and 20 mg/kg b.w., oral) dose-dependently reduced the bilirubin level. EEPA treatment also upregulated hepatic CAR and CYP3A1, accounting for its ability to facilitate bilirubin clearance. A single dose of EEPA (20 mg/kg b.w.) induced higher level of bilirubin clearance than phototherapy, widely used for treating neonatal jaundice. Furthermore, phenylhydrazine administration significantly increased MDA, protein carbonyl, and total thiol content and lowered the GSH level along with superoxide dismutase and catalase activity in erythrocyte compared to the control group. Single administration of EEPA (20 mg/kg b.w.) significantly reversed the trend. Presence of gallic acid, gentisic acid, and ortho-coumaric acid in EEPA was identified by HPLC analysis. Amongst these, the major phenolic constituent, gallic acid, exhibited significant bilirubin-lowering effect. These results suggested that P. amarus may be beneficial in reducing bilirubin level as well as oxidative stress in neonatal jaundice.

  1. Dual Effects of Bilirubin on the Proliferation of Rat Renal NRK52E Cells and ITS Association with Gap Junctions

    PubMed Central

    Wang, Yanling; Zhu, Qiongfang; Luo, Chenfang; Zhang, Ailan; Hei, Ziqing; Su, Guangjie; Xia, Zhengyuan; Irwin, Michael G.

    2013-01-01

    Objective: The effect of bilirubin on renal pathophysiology is controversial. This study aimed to observe the effects of bilirubin on the proliferation of normal rat renal tubular epithelial cell line (NRK52E) and its potential interplay with gap junction function. Methods: Cultured NRK52E cells, seeded respectively at high- or low- densities, were treated with varying concentrations of bilirubin for 24 hours. Cell injury was assessed by measuring cell viability and proliferation, and gap junction function was assessed by Parachute dye-coupling assay. Connexin 43 protein was assessed by Western blotting. Results: At doses from 17.1 to 513μmol/L, bilirubin dose-dependently enhanced cell viability and colony-formation rates when cells were seeded at either high- or low- densities (all p<0.05 vs. solvent group) accompanied with enhanced intercellular fluorescence transmission and increased Cx43 protein expression in high-density cells. However, the above effects of BR were gradually reversed when its concentration increased from 684 to 1026μmol/L. In high-density cells, gap junction inhibitor 12-O-tetradecanoylphorbol 13-acetate attenuated bilirubin-induced enhancement of colony-formation and fluorescence transmission. However, in the presence of high concentration bilirubin (1026μmol/L), activation of gap junction with retinoid acid decreased colony-formation rates. Conclusion: Bilirubin can confer biphasic effects on renal NRK52E cell proliferation potentially by differentially affecting gap junction functions. PMID:23930103

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

    PubMed

    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 (CO2) 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.

  3. The effect of bilirubin on the excitability of mitral cells in the olfactory bulb of the rat

    PubMed Central

    Chen, Xiao-Juan; Zhou, Hui-Qun; Ye, Hai-bo; Li, Chun-Yan; Zhang, Wei-Tian

    2016-01-01

    Olfactory dysfunction is a common clinical phenomenon observed in various liver diseases. Previous studies have shown a correlation between smell disorders and bilirubin levels in patients with hepatic diseases. Bilirubin is a well-known neurotoxin; however, its effect on neurons in the main olfactory bulb (MOB), the first relay in the olfactory system, has not been examined. We investigated the effect of bilirubin (>3 μM) on mitral cells (MCs), the principal output neurons of the MOB. Bilirubin increased the frequency of spontaneous firing and the frequency but not the amplitude of spontaneous excitatory postsynaptic currents (sEPSCs). TTX completely blocked sEPSCs in almost all of the cells tested. Bilirubin activity was partially blocked by N-methyl-D-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepro pionic acid (AMPA) receptor antagonists. Furthermore, we found that bilirubin increased the frequency of intrinsic firing independent of synaptic transmission in MCs. Our findings suggest that bilirubin enhances glutamatergic transmission and strengthens intrinsic firing independent of synaptic transmission, all of which cause hyperexcitability in MCs. Our findings provide the basis for further investigation into the mechanisms underlying olfactory dysfunction that are often observed in patients with severe liver disease. PMID:27611599

  4. Monoamine Oxidase Inhibitors: Clinical Review

    PubMed Central

    Remick, Ronald A.; Froese, Colleen

    1990-01-01

    Monoamine oxidase inhibitors (MAOIs) are effective antidepressant agents. They are increasingly and effectively used in a number of other psychiatric and non-psychiatric medical syndromes. Their potential for serious toxicity (i.e., hypertensive reaction) is far less than original reports suggest, and newer reversible substrate-specific MAOIs may offer even less toxicity. The author reviews the pharmacology, mechanism of action, clinical indications, and dosing strategies of MAOIs. The common MAOI side-effects (hypotension, weight gain, sexual dysfunction, insomnia, daytime sedation, myoclonus, and hypertensive episodes) are described and management techniques suggested. Recent clinical developments involving MAOIs are outlined. PMID:21233984

  5. Evaluation of bilirubin interference and accuracy of six creatinine assays compared with isotope dilution-liquid chromatography mass spectrometry.

    PubMed

    Nah, Hyunjin; Lee, Sang-Guk; Lee, Kyeong-Seob; Won, Jae-Hee; Kim, Hyun Ok; Kim, Jeong-Ho

    2016-02-01

    The aim of this study was to estimate bilirubin interference and accuracy of six routine methods for measuring creatinine compared with isotope dilution-liquid chromatography mass spectrometry (ID-LC/MS). A total of 40 clinical serum samples from 31 patients with serum total bilirubin concentration >68.4μmol/L were collected. Serum creatinine was measured using two enzymatic reagents and four Jaffe reagents as well as ID-LC/MS. Correlations between bilirubin concentration and percent difference in creatinine compared with ID-LC/MS were analyzed to investigate bilirubin interference. Bias estimations between the six reagents and ID-LC/MS were performed. Recovery tests using National Institute of Standards and Technology (NIST) Standard Reference Material (SRM) 967a were also performed. Both the enzymatic methods showed no bilirubin interference. However, three of the four Jaffe methods demonstrated significant bilirubin concentration-dependent interference in samples with creatinine levels <53μmol/L, and two of them showed significant bilirubin interference in samples with creatinine levels ranging from 53.0 to 97.2μmol/L. Comparison of these methods with ID-LC/MS using patients' samples with elevated bilirubin revealed that the tested methods failed to achieve the bias goal at especially low levels of creatinine. In addition, recovery test using NIST SRM 967a showed that bias in one Jaffe method and two enzymatic methods did not achieve the bias goal at either low or high level of creatinine, indicating they had calibration bias. One enzymatic method failed to achieve all the bias goals in both comparison experiment and recovery test. It is important to understand that both bilirubin interference and calibration traceability to ID-LC/MS should be considered to improve the accuracy of creatinine measurement. Copyright © 2015 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  6. Association of serum total bilirubin with renal outcome in Japanese patients with stages 3-5 chronic kidney disease.

    PubMed

    Sakoh, Teppei; Nakayama, Masaru; Tanaka, Shigeru; Yoshitomi, Ryota; Ura, Yoriko; Nishimoto, Hitomi; Fukui, Akiko; Shikuwa, Yui; Tsuruya, Kazuhiko; Kitazono, Takanari

    2015-09-01

    Serum bilirubin has been reported to be associated with the progression of kidney disease in patients with diabetic nephropathy. Less is known, however, about the relationship between bilirubin and chronic kidney disease (CKD) of other etiologies. This study was designed to clarify whether serum total bilirubin concentration is associated with kidney disease progression in patients with CKD independent of etiology. This prospective observational study enrolled 279 consecutive patients with stages 3-5 CKD. The renal endpoint was the composite of the doubling of serum creatinine or end-stage renal disease requiring dialysis. Patients were divided into three groups by their serum total bilirubin concentrations: ≤0.3 (lowest), 0.4-0.5 (middle), and ≥0.6 (highest) mg/dL. A Cox proportional hazards model was applied to determine the risk factors for poor renal outcome. The median follow-up period was 21months. One-hundred and three patients reached renal end points. After multivariable adjustment, a 0.1mg/dL increase in serum bilirubin was associated negatively with poor renal outcome (hazard ratio [HR], 0.73; 95% confidence interval [CI], 0.60-0.87). In addition, after adjustment for confounding factors, including traditional and nontraditional cardiovascular risk factors, the middle (HR 3.14, 95% CI 1.36-8.57) and lowest (HR 4.22, 95% CI 1.81-11.59) bilirubin groups had significantly higher HRs for renal outcome than the highest bilirubin group. Lower serum bilirubin concentration was independently associated with adverse renal outcomes, suggesting that the measurement of serum bilirubin is useful for predicting kidney disease progression in patients with moderate to severe CKD. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Looking to the horizon: the role of bilirubin in the development and prevention of age-related chronic diseases.

    PubMed

    Wagner, Karl-Heinz; Wallner, Marlies; Mölzer, Christine; Gazzin, Silvia; Bulmer, Andrew Cameron; Tiribelli, Claudio; Vitek, Libor

    2015-07-01

    Bilirubin, the principal tetrapyrrole, bile pigment and catabolite of haem, is an emerging biomarker of disease resistance, which may be related to several recently documented biological functions. Initially believed to be toxic in infants, the perception of bilirubin has undergone a transformation: it is now considered to be a molecule that may promote health in adults. Data from the last decade demonstrate that mildly elevated serum bilirubin levels are strongly associated with reduced prevalence of chronic diseases, particularly cardiovascular diseases (CVDs), as well as CVD-related mortality and risk factors. Recent data also link bilirubin to other chronic diseases, including cancer and Type 2 diabetes mellitus, and to all-cause mortality. Therefore, there is evidence to suggest that bilirubin is a biomarker for reduced chronic disease prevalence and a predictor of all-cause mortality, which is of important clinical significance. In the present review, detailed information on the association between bilirubin and all-cause mortality, as well as the pathological conditions of CVD, cancer, diabetes and neurodegenerative diseases, is provided. The mechanistic background concerning how bilirubin and its metabolism may influence disease prevention and its clinical relevance is also discussed. Given that the search for novel biomarkers of these diseases, as well as for novel therapeutic modalities, is a key research objective for the near future, bilirubin represents a promising candidate, meeting the criteria of a biomarker, and should be considered more carefully in clinical practice as a molecule that might provide insights into disease resistance. Clearly, however, greater molecular insight is warranted to support and strengthen the conclusion that bilirubin can prevent disease, with future research directions also proposed.

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

    PubMed

    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.

  9. Gene therapy with bilirubin-UDP-glucuronosyltransferase in the Gunn rat model of Crigler-Najjar syndrome type 1.

    PubMed

    Li, Q; Murphree, S S; Willer, S S; Bolli, R; French, B A

    1998-03-01

    Crigler-Najjar syndrome type 1 (CN type 1) is an autosomal recessive disorder characterized by nonhemolytic jaundice resulting from mutations to the gene encoding bilirubin-UDP-glucuronosyltransferase (UDPGT). The Gunn rat is an accurate animal model of this disease because the bilirubin-UDPGT gene in this strain carries a premature stop codon. The primary objective of this study was to complement this deficiency in vivo using liver-directed gene therapy. The efficiency of adenovirus type 5 (Ad5)-mediated gene transfer to the neonatal rat liver was first assessed by intravenous (i.v.) injection of an Ad5 vector carrying a nuclear-localized LacZ gene. An Ad5 vector expressing the cDNA encoding human bilirubin-UDPGT (Ad5/CMV/hUG-Br1) was then generated and injected i.v. into neonatal Gunn rats. Plasma samples were collected and bilirubin levels were determined at regular intervals. Although the mean level of bilirubin in homozygous Gunn rats 1-2 days after birth was already 14.5-fold higher than that of heterozygous siblings, treatment with Ad5/CMV/hUG-Br1 reduced plasma bilirubin to normal levels within 1 week. Plasma bilirubin in the treated homozygous rats remained normal for 4 weeks before gradually climbing to intermediate levels that were approximately half that of untreated homozygotes by 12 weeks. Administration of Ad5-mediated gene therapy to neonatal Gunn rats effectively complemented the deficiency in bilirubin-UDPGT, resulting in substantial reductions in plasma bilirubin over a 3-month period. The efficacy of Ad5-mediated gene therapy in neonates suggests that this approach might be effective against other hepatic disorders, including autosomal recessive deficiencies in lipid metabolism and vascular homeostasis.

  10. Magnetic state of the alpha 3 center of cytochrome c oxidase and some of its derivatives.

    PubMed

    Barnes, Z K; Babcock, G T; Dye, J L

    1991-07-30

    The temperature dependence of the magnetic susceptibility was used to investigate the nature of the coupling between cytochrome alpha 3 and CuB in resting and oxidized cyanide- and formate-bound cytochrome oxidase. Resting and formate-bound enzymes were found to have strong antiferromagnetic coupling with an S = 5/2 cytochrome alpha 3, results that were independent of the dispersing detergent and the enzyme isolation method. The cyanide-bound enzyme was heterogeneous, with a minor fraction showing intermediate strength antiferromagnetic coupling. The magnitude of this coupling was independent of the enzyme isolation method and depended moderately on the identity of the dispersing detergent. The major fraction of the cyanide-bound enzyme had a lowest energy state of Ms = 0. The coupling constant for this fraction did not depend on the isolation technique or on the identity of the dispersing detergent. The use of glucose-glucose oxidase to deoxygenate samples influenced the susceptibility behavior of some preparations of both the resting and formate-bound enzymes, with results indicating an S = 3/2 cytochrome alpha 3 in the resting enzyme samples. Retention of a 417-nm Soret band for formate-bound enzyme concomitant with peroxide-induced changes in susceptibility behavior indicates different sites of enzyme interactions for the formate ion and hydrogen peroxide.

  11. Bounding Species Distribution Models

    NASA Technical Reports Server (NTRS)

    Stohlgren, Thomas J.; Jarnevich, Cahterine S.; Morisette, Jeffrey T.; Esaias, Wayne E.

    2011-01-01

    Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for "clamping" model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART) and maximum entropy (Maxent) models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5): 642-647, 2011].

  12. Bounding species distribution models

    USGS Publications Warehouse

    Stohlgren, T.J.; Jarnevich, C.S.; Esaias, W.E.; Morisette, J.T.

    2011-01-01

    Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for "clamping" model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART) and maximum entropy (Maxent) models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used. ?? 2011 Current Zoology.

  13. Causality and Tsirelson's bounds

    SciTech Connect

    Buhrman, H.; Massar, S.

    2005-11-15

    We study the properties of no-signaling correlations that cannot be reproduced by local measurements on entangled quantum states. We say that such correlations violate Tsirelson bounds. We show that if these correlations are obtained by some reversible unitary quantum evolution U, then U cannot be written in the product form U{sub A}xU{sub B}. This implies that U can be used for signaling and for entanglement generation. This result is completely general and in fact can be viewed as a characterization of Tsirelson bounds. We then show how this result can be used as a tool to study Tsirelson bounds and we illustrate this by rederiving the Tsirelson bound of 2{radical}(2) for the Clauser-Horn-Shimony-Holt inequality, and by deriving a new Tsirelson bound for qutrits.

  14. Bounding Species Distribution Models

    NASA Technical Reports Server (NTRS)

    Stohlgren, Thomas J.; Jarnevich, Cahterine S.; Morisette, Jeffrey T.; Esaias, Wayne E.

    2011-01-01

    Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for "clamping" model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART) and maximum entropy (Maxent) models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5): 642-647, 2011].

  15. Multicopper manganese oxidase accessory proteins bind Cu and heme.

    PubMed

    Butterfield, Cristina N; Tao, Lizhi; Chacón, Kelly N; Spiro, Thomas G; Blackburn, Ninian J; Casey, William H; Britt, R David; Tebo, Bradley M

    2015-12-01

    Multicopper oxidases (MCOs) catalyze the oxidation of a diverse group of metal ions and organic substrates by successive single-electron transfers to O2 via four bound Cu ions. MnxG, which catalyzes MnO2 mineralization by oxidizing both Mn(II) and Mn(III), is unique among multicopper oxidases in that it carries out two energetically distinct electron transfers and is tightly bound to accessory proteins. There are two of these, MnxE and MnxF, both approximately 12kDa. Although their sequences are similar to those found in the genomes of several Mn-oxidizing Bacillus species, they are dissimilar to those of proteins with known function. Here, MnxE and MnxF are co-expressed independent of MnxG and are found to oligomerize into a higher order stoichiometry, likely a hexamer. They bind copper and heme, which have been characterized by electron paramagnetic resonance (EPR), X-ray absorption spectroscopy (XAS), and UV-visible (UV-vis) spectrophotometry. Cu is found in two distinct type 2 (T2) copper centers, one of which appears to be novel; heme is bound as a low-spin species, implying coordination by two axial ligands. MnxE and MnxF do not oxidize Mn in the absence of MnxG and are the first accessory proteins to be required by an MCO. This may indicate that Cu and heme play roles in electron transfer and/or Cu trafficking.

  16. Mitochondrial cytochrome c oxidase deficiency.

    PubMed

    Rak, Malgorzata; Bénit, Paule; Chrétien, Dominique; Bouchereau, Juliette; Schiff, Manuel; El-Khoury, Riyad; Tzagoloff, Alexander; Rustin, Pierre

    2016-03-01

    As with other mitochondrial respiratory chain components, marked clinical and genetic heterogeneity is observed in patients with a cytochrome c oxidase deficiency. This constitutes a considerable diagnostic challenge and raises a number of puzzling questions. So far, pathological mutations have been reported in more than 30 genes, in both mitochondrial and nuclear DNA, affecting either structural subunits of the enzyme or proteins involved in its biogenesis. In this review, we discuss the possible causes of the discrepancy between the spectacular advances made in the identification of the molecular bases of cytochrome oxidase deficiency and the lack of any efficient treatment in diseases resulting from such deficiencies. This brings back many unsolved questions related to the frequent delay of clinical manifestation, variable course and severity, and tissue-involvement often associated with these diseases. In this context, we stress the importance of studying different models of these diseases, but also discuss the limitations encountered in most available disease models. In the future, with the possible exception of replacement therapy using genes, cells or organs, a better understanding of underlying mechanism(s) of these mitochondrial diseases is presumably required to develop efficient therapy. © 2016 Authors; published by Portland Press Limited.

  17. Immunological comparison of sulfite oxidase

    SciTech Connect

    Pollock, V.; Barber, M.J. )

    1991-03-11

    Polyclonal antibodies (rabbit), elicited against FPLC-purified chicken and rat liver sulfite oxidase (SO), have been examined for inhibition and binding to purified chicken (C), rat (R), bovine (B), alligator (A) and shark (S) liver enzymes. Anti-CSO IgG cross-reacted with all five enzymes, with varying affinities, in the order CSO=ASO{gt}RSO{gt}BSO{gt}SSO. Anti-ROS IgG also cross-reacted with all five enzymes in the order RSO{gt}CSO=ASO{gt}BSO{gt}SSO. Anti-CSO IgG inhibited sulfite:cyt. c reductase (S:CR), sulfite:ferricyanide reductase (S:FR) and sulfite:dichlorophenolindophenol reductase (S:DR) activities of CSO to different extents (S:CR{gt}S:FR=S:DR). Similar differential inhibition was found for anti-ROS IgG and RSO S:CR, S:FR and S:DR activities. Anti-CSO IgG inhibited S:CR activities in the order CSO=ASO{much gt}SSO{gt}BSO. RSO was uninhibited. For anti-RSO IgG the inhibition order was RSO{gt}SSO{gt}BSO{gt}ASO. CSO was uninhibited. Anti-CSO and RSO IgGs partially inhibited Chlorella nitrate reductase (NR). Minor cross-reactivity was found for xanthine oxidase. Common antigenic determinants for all five SO's and NR are indicated.

  18. Mitochondrial Cytochrome c Oxidase Deficiency

    PubMed Central

    Rak, Malgorzata; Bénit, Paule; Chrétien, Dominique; Bouchereau, Juliette; Schiff, Manuel; El-Khoury, Riyad; Tzagoloff, Alexander; Rustin, Pierre

    2016-01-01

    As with other mitochondrial respiratory chain components, marked clinical and genetic heterogeneity is observed in patients with a cytochrome c oxidase deficiency. This constitutes a considerable diagnostic challenge and raises a number of puzzling questions. So far, pathological mutations have been reported in more than 30 genes, in both mitochondrial and nuclear DNA, affecting either structural subunits of the enzyme or proteins involved in its biogenesis. In this review, we discuss the possible causes of the discrepancy between the spectacular advances made in the identification of the molecular bases of cytochrome oxidase deficiency and the lack of any efficient treatment in diseases resulting from such deficiencies. This brings back many unsolved questions related to the frequent delay of clinical manifestation, variable course and severity, and tissue-involvement often associated with these diseases. In this context, we stress the importance to study different models of these diseases, but also discuss the limitations encountered in most available disease models. In the future, with the possible exception of replacement therapy using genes, cells or organs, a better understanding of underlying mechanism(s) of these mitochondrial diseases is presumably required to develop efficient therapy. PMID:26846578

  19. In vivo oxalate degradation by liposome encapsulated oxalate oxidase in rat model of hyperoxaluria

    PubMed Central

    Dahiya, Tulika; Pundir, C.S.

    2013-01-01

    Background & objectives: High level of urinary oxalate substantially increases the risk of hyperoxaluria, a significant risk factor for urolithiasis. The primary goal of this study was to reduce urinary oxalate excretion employing liposome encapsulated oxalate oxidase in animal model. Methods: A membrane bound oxalate oxidase was purified from Bougainvillea leaves. The enzyme in its native form was less effective at the physiological pH of the recipient animal. To increase its functional viability, the enzyme was immobilized on to ethylene maleic anhydride (EMA). Rats were injected with liposome encapsulated EMA- oxalate oxidase and the effect was observed on degradation of oxalic acid. Results: The enzyme was purified to apparent homogeneity with 60-fold purification and 31 per cent yield. The optimum pH of EMA-derivative enzyme was 6.0 and it showed 70 per cent of its optimal activity at pH 7.0. The EMA-bound enzyme encapsulated into liposome showed greater oxalate degradation in 15 per cent casein vitamin B6 deficient fed rats as compared with 30 per cent casein vitamin B6 deficient fed rats and control rats. Interpretation & conclusions: EMA-oxalate oxidase encapsulated liposome caused oxalate degradation in experimental hyperoxaluria indicating that the enzyme could be used as a therapeutic agent in hyperoxaluria leading to urinary stones. PMID:23481063

  20. Organically bound tritium

    SciTech Connect

    Diabate, S.; Strack, S. )

    1993-12-01

    Tritium released into the environment may be incorporated into organic matter. Organically bound tritium in that case will show retention times in organisms that are considerably longer than those of tritiated water which has significant consequences on dose estimates. This article reviews the most important processes of organically bound tritium production and transport through food networks. Metabolic reactions in plant and animal organisms with tritiated water as a reaction partner are of great importance in this respect. The most important production process, in quantitative terms, is photosynthesis in green plants. The translocation of organically bound tritium from the leaves to edible parts of crop plants should be considered in models of organically bound tritium behavior. Organically bound tritium enters the human body on several pathways, either from the primary producers (vegetable food) or at a higher tropic level (animal food). Animal experiments have shown that the dose due to ingestion of organically bound tritium can be up to twice as high as a comparable intake of tritiated water in gaseous or liquid form. In the environment, organically bound tritium in plants and animals is often found to have higher specific tritium concentrations than tissue water. This is not due to some tritium enrichment effects but to the fact that no equilibrium conditions are reached under natural conditions. 66 refs.

  1. Liquor Bilirubin Levels in Normal Pregnancy: A Reassessment of Early Prediction of Haemolytic Disease

    PubMed Central

    Murray, John; Norrie, D. L.; Ruthven, C. R. J

    1970-01-01

    A comparison was made between chemically and spectrophotometrically determined concentrations of total bile pigment in the liquor amnii. For the period 16 to 26 weeks' gestation the upper limit of normal bile pigment to protein ratio was found to be 0·4. Levels above this would be required as an indication for intrauterine transfusion. In 110 cases of isoimmunization of pregnancy these criteria were applied in the diagnosis of severity of the condition. The ratio of the bile pigment to protein was used rather than a simple bile pigment measurement, and found to be valuable. Nevertheless, it is important to emphasize that fallacious high bilirubin readings may arise by using whatever method, particularly owing to bilirubin and other breakdown products of blood contaminating the liquor. PMID:4991485

  2. Societal impact of bilirubin-induced hearing impairment in resource-limited nations.

    PubMed

    Olusanya, Bolajoko O

    2015-02-01

    Infants with bilirubin-induced neurologic dysfunction (BIND) are characterized by several developmental disabilities including auditory impairments. This paper explores the societal impact of bilirubin-induced auditory impairments, inclusive of hearing impairments and auditory neuropathy spectrum disorders, on these infants, their families, and on the community in resource-limited countries (per capita income of US$6,000 or less). Auditory impairments have substantial emotional, social, and economic impact on the affected infants, their families and communities. The burden is exacerbated by widespread poverty, unfavorable community attitudes towards disabilities, and lack of requisite health, educational, and social services. Curtailing the incidence of avoidable severe hyperbilirubinemia through proactive and effective management of infants at risk or with severe hyperbilirubinemia is necessary at all levels of healthcare delivery. Early detection and intervention for unavoidable auditory impairments should be widely promoted to provide improved developmental trajectories for the affected infants. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Specific labeling and partial inactivation of cytochrome oxidase by fluorescein mercuric acetate.

    PubMed

    Stonehuerner, J; O'Brien, P; Kendrick, L; Hall, J; Millett, F

    1985-09-25

    Addition of 1 eq of fluorescein mercuric acetate (FMA) to beef heart cytochrome oxidase was found to inhibit the steady-state electron transfer activity by 50%, but further additions up to 10 eq had no additional effect on activity. The partial inhibition caused by FMA is thus similar to that observed with other mercury compounds (Mann, A. J., and Auer, H. E. (1980) J. Biol. Chem. 255, 454-458). The fluorescence of FMA was quenched by a factor of 10 upon binding to cytochrome oxidase, consistent with the involvement of a sulfhydryl group. However, addition of mercuric chloride to FMA-cytochrome oxidase resulted in an increase in fluorescence, suggesting that FMA was displaced from the high affinity binding site. Cytochrome c binding to FMA-cytochrome oxidase resulted in a 10% decrease in the fluorescence, possibly caused by Forster energy transfer from FMA to the cytochrome c heme. The binding site for FMA in cytochrome oxidase was investigated by carrying out sodium dodecyl sulfate gel electrophoresis under progressively milder dissociation conditions. When FMA-cytochrome oxidase was dissociated with 3% sodium dodecyl sulfate and 6 M urea, FMA was predominantly bound to subunit II following electrophoresis. However, when the dissociation was carried out at 4 degrees C in the absence of urea with progressively smaller amounts of lithium dodecyl sulfate, the labeling of subunit II decreased and that of subunit I increased. These experiments demonstrate that mercury compounds bind to a high affinity site on cytochrome oxidase, possibly located in subunit I, but then migrate to subunit II under the normal sodium dodecyl sulfate gel electrophoresis conditions. A definitive assignment of the high affinity binding site in the native enzyme cannot be made, however, because it is possible that mercury compounds can migrate from one sulfhydryl to another under even the mildest electrophoresis conditions.

  4. p21-activated kinase (Pak) regulates NADPH oxidase activation in human neutrophils

    PubMed Central

    Martyn, Kendra D.; Kim, Moon-Ju; Quinn, Mark T.; Dinauer, Mary C.; Knaus, Ulla G.

    2005-01-01

    The phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase plays an instrumental role in host defense and contributes to microbicial killing by releasing highly reactive oxygen species. This multicomponent enzyme is composed of membrane and cytosolic components that assemble in the plasma membrane or phagolysosome. While the guanosine S′-triphosphatase (GTPase) Rac2 has been shown to be a critical regulator of NADPH oxidase activity and assembly, the role of its effector, p21-activated kinase (Pak), in oxidase function has not been well defined. Using HIV-1 Tat-mediated protein transduction of Pak inhibitory domain, we show here that Pak activity is indeed required for efficient superoxide generation in intact neutrophils. Furthermore, we show that Pak translocates to the plasma membrane upon N-formyl-methionyl-leucyl-phenylalanine (fMLF) stimulation and colocalizes with translocated p47phox and with p22phox, a subunit of flavocytochrome b558. Although activated Pak phosphorylated several essential serine residues in the C-terminus of p47phox, direct binding to p47phox was not observed. In contrast, active Pak bound directly to p22phox, suggesting flavocytochrome b was the oxidase-associated membrane target of this kinase and this association may facilitate further phosphorylation of p47phox in the assembling NADPH oxidase complex. PMID:16099876

  5. Single mutations that redirect internal proton transfer in the ba3 oxidase from Thermus thermophilus

    PubMed Central

    Smirnova, Irina; Chang, Hsin-Yang; von Ballmoos, Christoph; Ädelroth, Pia; Gennis, Robert B.; Brzezinski, Peter

    2014-01-01

    The ba3-type cytochrome c oxidase from Thermus thermophilus is a membrane-bound proton pump. Results from earlier studies have shown that with the aa3-type oxidases proton uptake to the catalytic site and “pump site” occur simultaneously. However, with the ba3 oxidase the pump site is loaded before proton transfer to the catalytic site because the proton transfer to the latter is slower than with the aa3 oxidases. In addition, the timing of formation and decay of catalytic intermediates is different in the two types of oxidases. In the present study, we have investigated two mutant ba3 CytcOs in which residues of the proton pathway leading to the catalytic site as well as the pump site were exchanged, Thr312Val and Tyr244Phe. Even though the ba3 CytcO uses only a single proton pathway for transfer of the substrate and “pumped” protons, the amino-acid residue substitutions had distinctly different effects on the kinetics of proton transfer to the catalytic site and the pump site, respectively. The results indicate that the rates of these reactions can be modified independently by replacement of single residues within the proton pathway. Furthermore, the data suggest that the Thr312Val and Tyr244Phe mutations interfere with a structural rearrangement in the proton pathway that is rate limiting for proton transfer to the catalytic site. PMID:24004023

  6. Timing of electron and proton transfer in the ba(3) cytochrome c oxidase from Thermus thermophilus.

    PubMed

    von Ballmoos, Christoph; Lachmann, Peter; Gennis, Robert B; Ädelroth, Pia; Brzezinski, Peter

    2012-06-05

    Heme-copper oxidases are membrane-bound proteins that catalyze the reduction of O(2) to H(2)O, a highly exergonic reaction. Part of the free energy of this reaction is used for pumping of protons across the membrane. The ba(3) oxidase from Thermus thermophilus presumably uses a single proton pathway for the transfer of substrate protons used during O(2) reduction as well as for the transfer of the protons that are pumped across the membrane. The pumping stoichiometry (0.5 H(+)/electron) is lower than that of most other (mitochondrial-like) oxidases characterized to date (1 H(+)/electron). We studied the pH dependence and deuterium isotope effect of the kinetics of electron and proton transfer reactions in the ba(3) oxidase. The results from these studies suggest that the movement of protons to the catalytic site and movement to a site located some distance from the catalytic site [proposed to be a "proton-loading site" (PLS) for pumped protons] are separated in time, which allows individual investigation of these reactions. A scenario in which the uptake and release of a pumped proton occurs upon every second transfer of an electron to the catalytic site would explain the decreased proton pumping stoichiometry compared to that of mitochondrial-like oxidases.

  7. Single mutations that redirect internal proton transfer in the ba3 oxidase from Thermus thermophilus.

    PubMed

    Smirnova, Irina; Chang, Hsin-Yang; von Ballmoos, Christoph; Ädelroth, Pia; Gennis, Robert B; Brzezinski, Peter

    2013-10-08

    The ba3-type cytochrome c oxidase from Thermus thermophilus is a membrane-bound proton pump. Results from earlier studies have shown that with the aa3-type oxidases proton uptake to the catalytic site and "pump site" occurs simultaneously. However, with ba3 oxidase the pump site is loaded before proton transfer to the catalytic site because the proton transfer to the latter is slower than that with the aa3 oxidases. In addition, the timing of formation and decay of catalytic intermediates is different in the two types of oxidases. In the present study, we have investigated two mutant ba3 CytcOs in which residues of the proton pathway leading to the catalytic site as well as the pump site were exchanged, Thr312Val and Tyr244Phe. Even though ba3 CytcO uses only a single proton pathway for transfer of the substrate and "pumped" protons, the amino-acid residue substitutions had distinctly different effects on the kinetics of proton transfer to the catalytic site and the pump site. The results indicate that the rates of these reactions can be modified independently by replacement of single residues within the proton pathway. Furthermore, the data suggest that the Thr312Val and Tyr244Phe mutations interfere with a structural rearrangement in the proton pathway that is rate limiting for proton transfer to the catalytic site.

  8. Influence of bilirubin and other antioxidants on nitrergic relaxation in the pig gastric fundus.

    PubMed

    Colpaert, E E; Lefebvre, R A

    2000-03-01

    1. The influence of several antioxidants (bilirubin, urate, ascorbate, alpha-tocopherol, glutathione (GSH), Cu/Zn superoxide dismutase (SOD) and the manganese SOD mimic EUK-8) on nitrergic relaxations induced by either exogenous nitric oxide (NO; 10(-5) M) or electrical field stimulation (4 Hz; 10 s and 3 min) was studied in the pig gastric fundus. 2. Ascorbate (5x10(-4) M), alpha-tocopherol (4x10(-4) M), SOD (300 - 1000 u ml(-1)) and EUK-8 (3x10(-4) M) did not influence the relaxations to exogenous NO. In the presence of GSH (5x10(-4) M), the short-lasting relaxation to NO became biphasic, potentiated and prolonged. Urate (4x10(-4) M) and bilirubin (2x10(-4) M) also potentiated the relaxant effect of NO. None of the antioxidants influenced the electrically evoked relaxations. 3. 6-Anilino-5,8-quinolinedione (LY83583; 10(-5) M) had no influence on nitrergic nerve stimulation but nearly abolished the relaxant response to exogenous NO. Urate and GSH completely prevented this inhibitory effect, while it was partially reversed by SOD and bilirubin. Ascorbate, alpha-tocopherol and EUK-8 were without effect. 4. Hydroquinone (10(-4) M) did not affect the electrically induced nitrergic relaxations, but markedly reduced NO-induced relaxations. The inhibition of exogenous NO by hydroquinone was completely prevented by urate and GSH. SOD and ascorbate afforded partial protection, while bilirubin, EUK-8 and alpha-tocopherol were ineffective. 5. Hydroxocobalamin (10(-4) M) inhibited relaxations to NO by 50%, but not the electrically induced responses. Full protection versus this inhibitory effect was obtained with urate, GSH and alpha-tocopherol. 6. These results strengthen the hypothesis that several endogenous antioxidant defense mechanisms, enzymatic as well as non-enzymatic, might play a role in the nitrergic neurotransmission process.

  9. Association of Low Serum Concentration of Bilirubin with Increased Risk of Coronary Artery Disease

    DTIC Science & Technology

    1994-01-01

    concentrations were decreased in individuals baseline tracing obtained before the subjects reached with CAD, whereas some of the liver-function enzyme age...Angiographic Data lis, IN). After July 1987, dextran sulfate, Mr 50 000 Summary statistics for the two groups are given in (Ciba Corning, Oberlin, OH), was...low serum bilirubin con- activity or increases in iron stores (9). centrations have been associated with good health, and It remains to be seen

  10. Antioxidant potential of bilirubin-accelerated wound healing in streptozotocin-induced diabetic rats.

    PubMed

    Ram, Mahendra; Singh, Vishakha; Kumar, Dhirendra; Kumawat, Sanjay; Gopalakrishnan, Anu; Lingaraju, Madhu C; Gupta, Priyanka; Tandan, Surendra Kumar; Kumar, Dinesh

    2014-10-01

    Oxidative injury is markedly responsible for wound complications in diabetes mellitus. The biological actions of bilirubin may be relevant to prevent oxidant-mediated cell death, as bilirubin application at a low concentration scavenges reactive oxygen species. Hence, we hypothesized that topical bilirubin application might improve wound healing in diabetic rats. Diabetes was induced in adult male Wistar rats, which were divided into two groups, i.e., diabetic control and diabetic treated. Non-diabetic healthy rats were also taken as healthy control group. Wound area was measured on days 3, 7, 14, and 19 post-wounding. The levels of malondialdehyde (MDA) and reduced glutathione (GSH) and the activities of glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) were estimated in the granulation tissue. There was a significant increase in percent wound closure in healthy control and diabetic treated rats on days 7, 14, and 19, as compared to diabetic control rats on days 7, 14, and 19. There was significant decrease in MDA levels on days 7, 14, and 19 in diabetic treated rats, as compared to diabetic control rats. Levels of GSH were significantly increased on days 3, 7, 14, and 19 in diabetic treated rats, as compared to diabetic control rats. GPx, SOD, and CAT activities were significantly higher on days 3, 7, and 14 in diabetic treated rats, as compared to diabetic control rats. The findings indicate that bilirubin is effective in reducing the oxidant status in wounds of diabetic rats which might have accelerated wound healing in these rats.

  11. Decreased neonatal jaundice readmission rate after implementing hyperbilirubinemia guidelines and universal screening for bilirubin.

    PubMed

    Alkalay, Arie L; Bresee, Catherine J; Simmons, Charles F

    2010-09-01

    Readmission rate for neonatal jaundice approximate 10 per 1000 live births. After applying hyperbilirubinemia guidelines and universal screening for bilirubin in term and near-term newborns, the readmission rate declined significantly from 24 to 3.7 per 1000 live births. Decreased readmission rate for neonatal jaundice may reduce kernicterus rate and health care costs. Further studies are necessary to explore these potential benefits.

  12. Low solubility of unconjugated bilirubin in dimethylsulfoxide – water systems: implications for pKa determinations

    PubMed Central

    2002-01-01

    Background Aqueous pKa values of unconjugated bilirubin are important determinants of its solubility and transport. Published pKa data on an analog, mesobilirubin-XIIIα, studied by 13C-NMR in buffered solutions containing 27 and 64 vol% (C2H3)2SO because of low aqueous solubility of mesobilirubin, were extrapolated to obtain pKa values in water of 4.2 and 4.9. Previous chloroform-water partition data on bilirubin diacid led to higher estimates of its pKa, 8.12 and 8.44, and its aqueous solubility. A thermodynamic analysis, using this solubility and a published solubility in DMSO, suggested that the systems used to measure 13C-NMR shifts were highly supersaturated. This expectation was assessed by measuring the residual concentrations of bilirubin in the supernatants of comparable DMSO-buffer systems, after mild centrifugation to remove microprecipitates. Results Extensive sedimentation was observed from numerous systems, many of which appeared optically clear. The very low supernatant concentrations at the lowest pH values (4.1-5.9) were compatible with the above thermodynamic analysis. Extensive sedimentation and low supernatant concentrations occurred also at pH as high as 7.2. Conclusions The present study strongly supports the validity of the aqueous solubility of bilirubin diacid derived from partition data, and, therefore, the corresponding high pKa values. Many of the mesobilirubin systems in the 13C-NMR studies were probably supersaturated, contained microsuspensions, and were not true solutions. This, and previously documented errors in pH determinations that caused serious errors in pKa values of the many soluble reference acids and mesobilirubin, raise doubts regarding the low pKa estimates for mesobilirubin from the 13C-NMR studies. PMID:12079498

  13. The antioxidant effect of free bilirubin on cumene-hydroperoxide treated human leukocytes.

    PubMed

    Yesilkaya, A; Altinayak, R; Korgun, D K

    2000-07-01

    To examine the antioxidant effect of bilirubin (BR) on leukocyte, we treated leukocytes obtained from healthy subjects with an oxidant and various concentrations of BR. High concentrations of BR decreased thiobarbituric acid reactive substances (TBARS) and catalase activities, increased superoxide dismutase (SOD) activity, but had no effect on glutathione (GSH) concentration. Our results showed that under physiological conditions, BR has an antioxidant effect only in high concentrations.

  14. Interference of Bilirubin in the Determination of Magnesium with Methyl Thymol Blue.

    PubMed

    Maksinovic, Rada; Ketin, Sonja; Biocanin, Rade

    2015-06-01

    Jaundice is a disease named for the yellow color of the skin. This color is the result of elevated levels of bilirubin in the blood serum. In Roma from Krusevac region in the last few years have seen the emergence of jaundice. In 80 of them (40 suffering and 40 from control group) were performed tests of numerous parameters in the laboratories of the Health Center in Krusevac. Magnesium was determined by spectrophotometry with methyl thymol blue, titanium yellow and blue xylidene. Bilirubin was determined by Jandrešek Grofov's method. The results were within the expectations, in addition to magnesium which was determined with methyl thymol blue. In all patients suffering from jaundice concentration of magnesium (0.67 ±0.14 mmol/l) statistically was significantly lower than tested of the control group (0.91± 0.059 mmol/). There is no theoretical data to reduce the concentration of magnesium in serum as a result of jaundice. That's why we determined magnesium both in the control group and in sufferings with two methods as the titanium yellow, and xylidene blew. With these two methods we obtained results that were examined were within normal limits. This has led us to conclude that the determination of bilirubin interferes with magnesium methyl thymol blue.

  15. Delta bilirubin: absorption spectra, molar absorptivity, and reactivity in the diazo reaction.

    PubMed

    Doumas, B T; Wu, T W; Jendrzejczak, B

    1987-06-01

    Delta bilirubin (B delta), isolated from serum, has an absorption maximum near 440 nm and a molar absorptivity of 72,000 L mol-1cm-1 in either Tris HCl (0.1 mol/L, pH 8.5) or phosphate (0.13 mol/L, pH 7.4) buffer. This absorptivity exceeds by approximately 50% and 59%, respectively, that of unconjugated bilirubin in the same buffers. This finding suggests that substantial errors can be incurred in direct spectrophotometry of bilirubins in serum. In the total diazo (TBIL) assay (Clin Chem 1985;31:1779-89), the color yield from B delta increases by 10% as the final diazo concentration is increased from 0.27 to 0.81 mmol/L. In the direct (DBIL) assay, if done in HCl (50 mmol/L), B delta yields approximately 15% more color as the diazo concentration is increased from 0.51 to 1.53 mmol/L, whereas in acetate buffer (0.4 mol/L, pH 4.7) the corresponding color yield is 25% greater. However, the absolute color yield for the reaction in HCl exceeds that in acetate buffer. In both the TBIL and the DBIL assay, B delta reacts slowly, nearly complete reaction requiring 10 min. Thus, B delta may be seriously underestimated in diazo (especially DBIL) methods in which short reaction times (20 s to 1 min) are used.

  16. Interference of Bilirubin in the Determination of Magnesium with Methyl Thymol Blue

    PubMed Central

    Maksinovic, Rada; Ketin, Sonja; Biocanin, Rade

    2015-01-01

    Introduction: Jaundice is a disease named for the yellow color of the skin. This color is the result of elevated levels of bilirubin in the blood serum. In Roma from Krusevac region in the last few years have seen the emergence of jaundice. Material and methods: In 80 of them (40 suffering and 40 from control group) were performed tests of numerous parameters in the laboratories of the Health Center in Krusevac. Magnesium was determined by spectrophotometry with methyl thymol blue, titanium yellow and blue xylidene. Bilirubin was determined by Jandrešek Grofov’s method. Results: The results were within the expectations, in addition to magnesium which was determined with methyl thymol blue. In all patients suffering from jaundice concentration of magnesium (0.67 ±0.14 mmol/l) statistically was significantly lower than tested of the control group (0.91± 0.059 mmol/). There is no theoretical data to reduce the concentration of magnesium in serum as a result of jaundice. That’s why we determined magnesium both in the control group and in sufferings with two methods as the titanium yellow, and xylidene blew. With these two methods we obtained results that were examined were within normal limits. Conclusion: This has led us to conclude that the determination of bilirubin interferes with magnesium methyl thymol blue. PMID:26244045

  17. Point-of-care device for quantification of bilirubin in skin tissue.

    PubMed

    Alla, Suresh K; Huddle, Adam; Butler, Joshua D; Bowman, Peggy S; Clark, Joseph F; Beyette, Fred R

    2011-03-01

    Steady state diffuse reflectance spectroscopy is a nondestructive method for obtaining biochemical and physiological information from skin tissue. In medical conditions such as neonatal jaundice excess bilirubin in the blood stream diffuses into the surrounding tissue leading to a yellowing of the skin. Diffuse reflectance measurement of the skin tissue can provide real time assessment of the progression of a disease or a medical condition. Here we present a noninvasive point-of-care system that utilizes diffuse reflectance spectroscopy to quantifying bilirubin from skin reflectance spectra. The device consists of an optical system integrated with a signal processing algorithm. The device is then used as a platform to study two different spectral databases. The first spectral database is a jaundice animal model in which the jaundice reflectance spectra are synthesized from normal skin. The second spectral database is the spectral measurements collected on human volunteers to quantify the different chromophores and other physical properties of the tissue such as Hematocrit, Hemoglobin, etc. The initial trials from each of these spectral databases have laid the foundation to verify the performance of this bilirubin quantification device.

  18. Post-test probability for neonatal hyperbilirubinemia based on umbilical cord blood bilirubin, direct antiglobulin test, and ABO compatibility results.

    PubMed

    Peeters, Bart; Geerts, Inge; Van Mullem, Mia; Micalessi, Isabel; Saegeman, Veroniek; Moerman, Jan

    2016-05-01

    Many hospitals opt for early postnatal discharge of newborns with a potential risk of readmission for neonatal hyperbilirubinemia. Assays/algorithms with the possibility to improve prediction of significant neonatal hyperbilirubinemia are needed to optimize screening protocols and safe discharge of neonates. This study investigated the predictive value of umbilical cord blood (UCB) testing for significant hyperbilirubinemia. Neonatal UCB bilirubin, UCB direct antiglobulin test (DAT), and blood group were determined, as well as the maternal blood group and the red blood cell antibody status. Moreover, in newborns with clinically apparent jaundice after visual assessment, plasma total bilirubin (TB) was measured. Clinical factors positively associated with UCB bilirubin were ABO incompatibility, positive DAT, presence of maternal red cell antibodies, alarming visual assessment and significant hyperbilirubinemia in the first 6 days of life. UCB bilirubin performed clinically well with an area under the receiver-operating characteristic curve (AUC) of 0.82 (95 % CI 0.80-0.84). The combined UCB bilirubin, DAT, and blood group analysis outperformed results of these parameters considered separately to detect significant hyperbilirubinemia and correlated exponentially with hyperbilirubinemia post-test probability. Post-test probabilities for neonatal hyperbilirubinemia can be calculated using exponential functions defined by UCB bilirubin, DAT, and ABO compatibility results. • The diagnostic value of the triad umbilical cord blood bilirubin measurement, direct antiglobulin testing and blood group analysis for neonatal hyperbilirubinemia remains unclear in literature. • Currently no guideline recommends screening for hyperbilirubinemia using umbilical cord blood. What is New: • Post-test probability for hyperbilirubinemia correlated exponentially with umbilical cord blood bilirubin in different risk groups defined by direct antiglobulin test and ABO blood group

  19. Virial Expansion Bounds

    NASA Astrophysics Data System (ADS)

    Tate, Stephen James

    2013-10-01

    In the 1960s, the technique of using cluster expansion bounds in order to achieve bounds on the virial expansion was developed by Lebowitz and Penrose (J. Math. Phys. 5:841, 1964) and Ruelle (Statistical Mechanics: Rigorous Results. Benjamin, Elmsford, 1969). This technique is generalised to more recent cluster expansion bounds by Poghosyan and Ueltschi (J. Math. Phys. 50:053509, 2009), which are related to the work of Procacci (J. Stat. Phys. 129:171, 2007) and the tree-graph identity, detailed by Brydges (Phénomènes Critiques, Systèmes Aléatoires, Théories de Jauge. Les Houches 1984, pp. 129-183, 1986). The bounds achieved by Lebowitz and Penrose can also be sharpened by doing the actual optimisation and achieving expressions in terms of the Lambert W-function. The different bound from the cluster expansion shows some improvements for bounds on the convergence of the virial expansion in the case of positive potentials, which are allowed to have a hard core.

  20. Effect of Blue Light on the Electronic and Structural Properties of Bilirubin Isomers: Insights into the Photoisomerization and Photooxidation Processes.

    PubMed

    Cardoso, Lucas C; Savedra, Ranylson M L; Silva, Mariana M; Ferreira, Giovana R; Bianchi, Rodrigo F; Siqueira, Melissa F

    2015-08-27

    The central process of neonatal phototherapy by employing blue light has been attributed to the configurational conversion of (4Z,15Z)-bilirubin to (4Z,15E). Indeed, photoisomerization is the early photochemical event during this procedure. However, in this paper, we show that the bilirubin solutions under continuous blue light exposure undergo a photooxidation process. To ascertain the role of this photodegradation in the phototherapy, we evaluated UV–visible absorption spectra obtained from bilirubin solutions in CHCl3, milli-Q water, and physiological saline, as well as FTIR spectroscopy for bilirubin in CHCl3. These analyses also showed that the first 2 h of phototherapy are the most relevant period. In addition, quantum molecular modeling using B3LYP/6-31G(d,p) and ZINDO/S-CIS was performed to evaluate the electronic and structural properties of four bilirubin isomers, showing that the (4Z,15E)-bilirubin isomer is the most polar configuration. Therefore, it can be more soluble in aqueous environments than the other configurations. This clarifies why this is the faster isomer excreted during the phototherapy.

  1. Serum bilirubin levels are lower in overweight asymptomatic middle-aged adults: an early indicator of metabolic syndrome?

    PubMed

    Jenko-Pražnikar, Zala; Petelin, Ana; Jurdana, Mihaela; Žiberna, Lovro

    2013-07-01

    Low levels of bilirubin have recently been associated with obesity, diabetes mellitus, and metabolic syndrome. Here, we hypothesized that serum bilirubin levels might be already altered in overweight asymptomatic middle-aged individuals before full development of the metabolic syndrome. Healthy nonsmoking adults aged 25-49 (64 women and 32 men) participated in this cross-sectional study. All participants who reported stable weight within the last three months underwent standard anthropomorphological measurements of body composition, blood pressure measurements, aerobic and anaerobic capabilities assessment, dietary intake evaluation, and fasting serological measurements of total and direct bilirubin, glucose, insulin, triglycerides, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and C-reactive protein. Participants were divided into normal-weight and overweight groups. Linear correlation and multiple regression analyses were used to examine the association of serum bilirubin levels with all metabolic syndrome risk factor changes. Serum bilirubin levels were lower in overweight healthy individuals of both sexes, and were negatively associated with abdominal obesity, insulin resistance, fasting glucose, fasting insulin, fasting triglycerides, total cholesterol, low-density lipoprotein cholesterol, and C-reactive protein levels but positively associated with aerobic body capabilities. Our findings suggest that serum bilirubin levels have the potential to be employed as an early biomarker for indicating asymptomatic individuals at increased risk of developing metabolic syndrome. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Effect of bilirubin concentration on the risk of diabetic complications: A meta-analysis of epidemiologic studies

    PubMed Central

    Zhu, Bo; Wu, Xiaomei; Bi, Yifei; Yang, Yang

    2017-01-01

    Diabetes can affect many parts of the body and is associated with serious complications. Oxidative stress is a major contributor in the pathogenesis of diabetic complications and bilirubin has been shown to have antioxidant effects. The number of studies on the effect of bilirubin on the risk of diabetic complications has increased, but the results are inconsistent. Thus, we performed a meta-analysis to determine the relationship between bilirubin concentration and the risk of diabetic complications, and to investigate if there was a dose-response relationship. We carried out an extensive search in multiple databases. A fixed or random-effects model was used to calculate the pooled estimates. We conducted a dose-response meta-analysis to analyze the association between these estimates. A total of 132,240 subjects from 27 included studies were analyzed in our meta-analysis. A negative nonlinear association between bilirubin concentration and the risk of diabetic complications was identified (OR: 0.77, 95% CI: 0.73–0.81), with a nonlinear association. We also found that there was a negative association between bilirubin concentration and the risk of diabetic nephropathy, diabetic retinopathy and diabetic neuropathy. The results of our meta-analysis indicate that bilirubin may play a protective role in the occurrence of diabetic complications. PMID:28134328

  3. High serum total bilirubin as a protective factor against hip bone loss in healthy middle-aged men.

    PubMed

    Kim, Beom-Jun; Koh, Jung-Min; Ahn, Seong Hee; Lee, Seung Hun; Kim, Eun Hee; Bae, Sung Jin; Kim, Hong-Kyu; Choe, Jae Won; Kim, Ghi Su

    2013-06-01

    Bilirubin is known to have a physiologic role as an antioxidant that efficiently scavenges peroxyl radicals and suppresses oxidation, and oxidative stress has detrimental effects on bone metabolism. In the present study, we performed a 3-year longitudinal study of healthy middle-aged men, investigating the association between serum total bilirubin concentrations and annualized changes in bone mineral density (BMD). The study enrolled a total of 917 Korean men aged 40 years or older who had undergone comprehensive routine health examinations with an average follow-up interval of 3 years. BMD at proximal femur sites was measured with dual-energy X-ray absorptiometry using the same equipment at baseline and follow-up. The overall mean annualized rates of bone loss at the total femur, femoral neck, and trochanter were -0.25 %/year, -0.34 %/year, and -0.44 %/year, respectively. After adjustment for potential confounders, the rates of bone loss at all proximal femur sites were significantly attenuated in a dose-response fashion across increasing bilirubin concentrations (P = 0.006-0.046). Moreover, compared to subjects in the lowest bilirubin quartile category, those in the highest bilirubin quartile category showed significantly less bone loss at all proximal femur sites after adjustment for confounding factors (P = 0.010-0.048). This study provides the first clinical evidence that serum total bilirubin could be a protective marker against future bone loss, especially in subjects without liver diseases.

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

    PubMed

    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.

  5. Does corticosteroid treatment cause prolonged recovery and increased total bilirubin level in severe ADAMTS-13-deficient TTP patient?

    PubMed

    Sayiner, Zeynel Abidin; Acik, Didar Yanardag; Yilmaz, Mehmet; Subari, Salih; Mete, Ayse Ozlem; Dai, M Sinan

    2015-10-01

    A 41-year-old female patient complaining of fatigue, headache, mild confusion, and rush on her lower extremities was admitted to our emergency department. Laboratory tests revealed that he had anemia, thrombocytopenia, and increased levels of indirect bilirubin and lactic dehydrogenase (LDH) in blood tests. Direct and indirect Coombs tests were negative, and fragmented erythrocytes were observed in peripheral blood smears. The patient was diagnosed with thrombotic thrombocytopenic purpura (TTP). The best supportive care was provided. Therapeutic plasma exchange (TPE) and 1 mg/kg methylprednisolone treatments were administered. On the 10th day of treatment, LDH level and fragmented red blood cells in peripheral blood smear were decreased, but his direct and indirect bilirubin levels increased despite the fact that he was treated with 1 mg/kg methylprednisolone and TPE. The patient had severe ADAMTS-13 deficiency. After discontinued steroids treatment, his bilirubin level normalized within 4 days. On the 4th day after bilirubin level normalized, vincristine treatment was administered. TPE was also continued. There was no consensus about the optimal schedule for discontinuing plasmapheresis therapy, and also we observed total bilirubin level improvement with discontinued corticosteroid treatment. In this case, corticosteroid treatment was linked with the increase of total bilirubin level in severe ADAMTS-13-deficient TTP patient.

  6. Usefulness of serum bilirubin levels as a biomarker for long-term clinical outcomes after percutaneous coronary intervention.

    PubMed

    Kim, Hyun-Wook; Choi, Dong-Hyun; Lim, Leejin; Lee, Young-Min; Kang, Joon Tae; Chae, Seung Seok; Ki, Young-Jae; Song, Heesang; Koh, Young-Youp

    2015-11-01

    The aim of this study was to evaluate the prognostic value of serum total bilirubin on the development of adverse outcomes after percutaneous coronary intervention (PCI) besides high-sensitivity cardiac troponin T (hs-cTnT) and N-terminal pro-B type natriuretic peptide (NT-proBNP). Serum total bilirubin, hs-cTnT, and NT-proBNP were analyzed in 372 patients who underwent PCI. The primary endpoint was cardiac death. There were 21 events of cardiac death during a mean of 25.8 months of follow-up. When the serum total bilirubin cut-off level (median value) was set to 0.58 mg/dL using the receiver operating characteristic curve, the sensitivity was 95.2 % and the specificity was 51.0 % for differentiating between the group with cardiac death and the group without cardiac death. Kaplan-Meier analysis revealed that the lower serum total bilirubin group (<0.58 mg/dL) had a significantly higher cardiac death rate than the higher serum total bilirubin group (≥0.58 mg/dL) (10.4 vs. 0.6 %, log-rank: P = 0.0001). In conclusion, low serum total bilirubin is a predictive marker for cardiac death after PCI.

  7. Making glucose oxidase fit for biofuel cell applications by directed protein evolution.

    PubMed

    Zhu, Ziwei; Momeu, Carmen; Zakhartsev, Maxim; Schwaneberg, Ulrich

    2006-05-15

    Progress in miniature chip-design raises demands for implantable power sources in health care applications such as continuous glucose monitoring of diabetic patients. Pioneered by Adam Heller, miniaturized enzymatic biofuel cells (mBCs) convert blood sugars into electrical energy by employing for example glucose oxidase (GOx) on the anode and bilirubin oxidase on the cathode. To match application demands it is crucial to increase lifetime and power output of mBCs. The power output has been limited by the performance of GOx on the anode. We developed a glucose oxidase detection assay (GODA) as medium-throughput screening system for improving GOx properties by directed protein evolution. GODA is a reaction product detection assay based on coupled enzymatic reactions leading to NADPH formation which is recorded at 340 nm. The main advantage of the assay is that it detects the production of d-gluconolactone instead of the side-product hydrogen peroxide and enables to improve bioelectrochemical properties of GOx. For validating the screening system, a mutagenic library of GOx from Aspergillus niger (EC 1.1.3.4) was generated and screened for improved activity using Saccharomyces cerevisiae as host. Directed evolution resulted in a GOx mutant I115V with 1.4-1.5-fold improved activity for beta-d-glucose (Vmax from 7.94 to 10.81 micromol min(-1) mg(-1); Km approximately 19-21 mM) and oxygen consumption kinetics correlate well [Vmax (O2) from 5.94 to 8.34 micromol min(-1) mg(-1); Km (O2) from 700 to 474 microM]. The developed mutagenic protocol and GODA represent a proof-of-principle that GOx can be evolved by directed evolution in S. cerevisiae for putative use in biofuel cells.

  8. Multicopper oxidase-3 is a laccase associated with the peritrophic matrix of Anopheles gambiae.

    PubMed

    Lang, Minglin; Kanost, Michael R; Gorman, Maureen J

    2012-01-01

    The multicopper oxidase (MCO) family of enzymes includes laccases, which oxidize a broad range of substrates including polyphenols and phenylendiamines; ferroxidases, which oxidize ferrous iron; and several other oxidases with specific substrates such as ascorbate, bilirubin or copper. The genome of Anopheles gambiae, a species of mosquito, encodes five putative multicopper oxidases. Of these five, only AgMCO2 has known enzymatic and physiological functions: it is a highly conserved laccase that functions in cuticle pigmentation and tanning by oxidizing dopamine and dopamine derivatives. AgMCO3 is a mosquito-specific gene that is expressed predominantly in adult midguts and Malpighian tubules. To determine its enzymatic function, we purified recombinant AgMCO3 and analyzed its activity. AgMCO3 oxidized hydroquinone (a p-diphenol), the five o-diphenols tested, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), and p-phenylenediamine, but not ferrous iron. The catalytic efficiencies of AgMCO3 were similar to those of cuticular laccases (MCO2 orthologs), except that AgMCO3 oxidized all of the phenolic substrates with similar efficiencies whereas the MCO2 isoforms were less efficient at oxidizing catechol or dopa. These results demonstrate that AgMCO3 can be classified as a laccase and suggest that AgMCO3 has a somewhat broader substrate specificity than MCO2 orthologs. In addition, we observed AgMCO3 immunoreactivity in the peritrophic matrix, which functions as a selective barrier between the blood meal and midgut epithelial cells, protecting the midgut from mechanical damage, pathogens, and toxic molecules. We propose that AgMCO3 may oxidize toxic molecules in the blood meal leading to detoxification or to cross-linking of the molecules to the peritrophic matrix, thus targeting them for excretion.

  9. Contribution of aldehyde oxidase, xanthine oxidase, and aldehyde dehydrogenase on the oxidation of aromatic aldehydes.

    PubMed

    Panoutsopoulos, Georgios I; Kouretas, Demetrios; Beedham, Christine

    2004-10-01

    Aliphatic aldehydes have a high affinity toward aldehyde dehydrogenase activity but are relatively poor substrates of aldehyde oxidase and xanthine oxidase. In addition, the oxidation of xenobiotic-derived aromatic aldehydes by the latter enzymes has not been studied to any great extent. The present investigation compares the relative contribution of aldehyde dehydrogenase, aldehyde oxidase, and xanthine oxidase activities in the oxidation of substituted benzaldehydes in separate preparations. The incubation of vanillin, isovanillin, and protocatechuic aldehyde with either guinea pig liver aldehyde oxidase, bovine milk xanthine oxidase, or guinea pig liver aldehyde dehydrogenase demonstrated that the three aldehyde oxidizing enzymes had a complementary substrate specificity. Incubations were also performed with specific inhibitors of each enzyme (isovanillin for aldehyde oxidase, allopurinol for xanthine oxidase, and disulfiram for aldehyde dehydrogenase) to determine the relative contribution of each enzyme in the oxidation of these aldehydes. Under these conditions, vanillin was rapidly oxidized by aldehyde oxidase, isovanillin was predominantly metabolized by aldehyde dehydrogenase activity, and protocatechuic aldehyde was slowly oxidized, possibly by all three enzymes. Thus, aldehyde oxidase activity may be a significant factor in the oxidation of aromatic aldehydes generated from amines and alkyl benzenes during drug metabolism. In addition, this enzyme may also have a role in the catabolism of biogenic amines such as dopamine and noradrenaline where 3-methoxyphenylacetic acids are major metabolites.

  10. Bilirubin conjugates in bile of man and rat in the normal state and in liver disease

    PubMed Central

    Fevery, J.; Damme, B. Van; Michiels, R.; Groote, J. De; Heirwegh, K. P. M.

    1972-01-01

    Conjugates of bilirubin were studied in normal bile of man and rat, and in bile of liver patients. In general human bile was obtained by duodenal intubation. In addition T-tube bile was examined in patients operated on for mechanical obstruction. The bile pigment compositions of duodenal and T-tube bile were similar in two patients where comparison was possible. Obstruction of the bile duct in rats was used as an animal model for obstructive jaundice. Diazotized ethyl anthranilate was used for determination of total conjugated bile pigment and for thin-layer chromatography (t.l.c.) analysis of the derived azopigments. The available t.l.c. procedures are versatile and allow rapid and quantitative analysis. A variety of conjugated azopigments can be distinguished. With chloroform, negligible amounts of unconjugated bilirubin are extracted from bile of man. Therefore, the percentage of monoconjugated bile pigments present in the initial bile sample can be calculated from the percentage of azodipyrrole found after diazotization. Normal bile from man and rat yields similar azopigment patterns. The dominant component is azopigment-δ (azodipyrrole β-D-monoglucuronoside). Small amounts of azopigments with complex conjugating structures (γ-azopigments) are present in both cases. Human bile further yields small amounts of azopigments containing xylose or glucose (called azopigments-α2 and -α3, respectively). Monoconjugated bilirubin (estimated from the percentage of azodipyrrole) amounts of 22% of total bile pigments in human bile and to 39% in murine bile. In both, the bulk of bile pigment is bilirubin diglucuronoside. From bile of patients with acquired liver diseases a new azopigment group (β-azopigment) was derived. The γ-azopigment group was increased; the δ-azopigment group (containing azodipyrrole β-D-monoglucuronoside) was decreased. No differentiation was possible between intra- and extrahepatic cholestasis. The percentage of β-azopigment showed a positive

  11. Dietary inhibitors of monoamine oxidase A.

    PubMed

    Dixon Clarke, Sarah E; Ramsay, Rona R

    2011-07-01

    Inhibition of monoamine oxidase is one way to treat depression and anxiety. The information now available on the pharmacokinetics of flavonoids and of the components of tobacco prompted an exploration of whether a healthy diet (with or without smoking) provides active compounds in amounts sufficient to partially inhibit monoamine oxidase. A literature search was used to identify dietary monoamine oxidase inhibitors, the levels of these compounds in foods, the pharmacokinetics of the absorption and distribution, and tissue levels observed. An estimated daily intake and the expected tissue concentrations were compared with the measured efficacies of the compounds as inhibitors of monoamine oxidases. Norharman, harman and quercetin dietary presence, pharmacokinetics, and tissue levels were consistent with significant levels reaching neuronal monoamine oxidase from the diet or smoking; 1,2,3,4-tetrahydroisoquinoline, eugenol, 1-piperoylpiperidine, and coumarin were not. Quercetin was equipotent with norharman as a monoamine oxidase A inhibitor and its metabolite, isorhamnetin, also inhibits. Total quercetin was the highest of the compounds in the sample diet. Although bioavailability was variable depending on the source, a healthy diet contains amounts of quercetin that might give sufficient amounts in brain to induce, by monoamine oxidase A inhibition, a small decrease in neurotransmitter breakdown.

  12. Transient elevation of serum bilirubin (a heme oxygenase-1 metabolite) level in hemorrhagic stroke: bilirubin is a marker of oxidant stress.

    PubMed

    Dohi, K; Mochizuki, Y; Satoh, K; Jimbo, H; Hayashi, M; Toyoda, I; Ikeda, Y; Abe, T; Aruga, T

    2003-01-01

    Bilirubin (Bil) is the end product of heme catabolism. The production of Bil reflects heme oxygenase-1 expression in response to oxidative stress in various diseases. To assess the role of Bil as a marker of oxidative stress in cases of brain damage, we measured serum Bil concentrations in patients with hemorrhagic stroke. Serum levels of total Bil were measured in 20 subarachnoid hemorrhage patients with symptomatic vasospasms and in 23 patients with intracerebral hemorrhage; concentrations were measured every day for 14 consecutive days. Serum Bil levels were significantly elevated in the early phases in both groups. Moreover, transient elevation was observed on the day prior to the observation of clinical manifestations of symptomatic vasospasm after SAH. Bil, known to be a powerful antioxidant, was induced after hemorrhagic stroke, reflecting the intensity of oxidative stress. Plasma Bil concentrations might serve as a useful marker of oxidative stress in hemorrhagic stroke patients.

  13. Location and catalytic characteristics of a multipotent bacterial polyphenol oxidase.

    PubMed

    Fernández, E; Sanchez-Amat, A; Solano, F

    1999-10-01

    The melanogenic marine bacterium Marinomonas mediterranea contains a multipotent polyphenol oxidase (PPO) able to oxidize substrates characteristic for tyrosinase and laccase. Thus, this enzyme shows tyrosine hydroxylase activity and it catalyzes the oxidation of a wide variety of o-diphenol as well as o-methoxy-activated phenols. The study of its sensitivity to different inhibitors also revealed intermediate features between laccase and tyrosinase. It is similar to tyrosinases in its sensitivity to tropolone, but it resembles laccases in its resistance to cinnamic acid and phenylthiourea, and in its sensitivity to fluoride anion. This enzyme is mostly membrane-bound and can be solubilized either by non-ionic detergent or lipase treatments of the membrane. The expression of this enzymatic activity is growth-phase regulated, reaching a maximum in the stationary phase of bacterial growth, but L-tyrosine, Cu(II) ions, or 2,5-xylidine do not induce it. This enzyme can be separated from a second PPO form by gel permeation chromatography. The second PPO is located in the soluble fraction and shows a sodium dodecyl sulfate (SDS)-activated action on the characteristic substrates for tyrosinase, L-tyrosine, and L-dopa, but it does not show activity towards laccase-specific substrates. The involvement of the multipotent PPO in melanogenesis and its relationship with the SDS-activated form and with the alternative functions proposed for multicopper oxidases in other microorganisms are discussed.

  14. Crystal Structure of the Deglycating Enzyme Fructosamine Oxidase (Amadoriase II)*

    PubMed Central

    Collard, François; Zhang, Jianye; Nemet, Ina; Qanungo, Kaustubha R.; Monnier, Vincent M.; Yee, Vivien C.

    2008-01-01

    Fructosamine oxidases (FAOX) catalyze the oxidative deglycation of low molecular weight fructosamines (Amadori products). These proteins are of interest in developing an enzyme to deglycate proteins implicated in diabetic complications. We report here the crystal structures of FAOX-II from the fungi Aspergillus fumigatus, in free form and in complex with the inhibitor fructosyl-thioacetate, at 1.75 and 1.6Å resolution, respectively. FAOX-II is a two domain FAD-enzyme with an overall topology that is most similar to that of monomeric sarcosine oxidase. Active site residues Tyr-60, Arg-112 and Lys-368 bind the carboxylic portion of the fructosamine, whereas Glu-280 and Arg-411 bind the fructosyl portion. From structure-guided sequence comparison, Glu-280 was identified as a signature residue for FAOX activity. Two flexible surface loops become ordered upon binding of the inhibitor in a catalytic site that is about 12Å deep, providing an explanation for the very low activity of FAOX enzymes toward protein-bound fructosamines, which would have difficulty accessing the active site. Structure-based mutagenesis showed that substitution of Glu-280 and Arg-411 eliminates enzyme activity. In contrast, modification of other active site residues or of amino acids in the flexible active site loops has little effect, highlighting these regions as potential targets in designing an enzyme that will accept larger substrates. PMID:18667417

  15. Crystal Structure of the Deglycating Enzyme Fructosamine Oxidase (Amadoriase ll)

    SciTech Connect

    Collard, F.; Zhang, J; Nemet, I; Qanungo, K; Monnier, V; Yee, V

    2008-01-01

    Fructosamine oxidases (FAOX) catalyze the oxidative deglycation of low molecular weight fructosamines (Amadori products). These proteins are of interest in developing an enzyme to deglycate proteins implicated in diabetic complications. We report here the crystal structures of FAOX-II from the fungi Aspergillus fumigatus, in free form and in complex with the inhibitor fructosyl-thioacetate, at 1.75 and 1.6{angstrom} resolution, respectively. FAOX-II is a two domain FAD-enzyme with an overall topology that is most similar to that of monomeric sarcosine oxidase. Active site residues Tyr-60, Arg-112 and Lys-368 bind the carboxylic portion of the fructosamine, whereas Glu-280 and Arg-411 bind the fructosyl portion. From structure-guided sequence comparison, Glu-280 was identified as a signature residue for FAOX activity. Two flexible surface loops become ordered upon binding of the inhibitor in a catalytic site that is about 12{angstrom} deep, providing an explanation for the very low activity of FAOX enzymes toward protein-bound fructosamines, which would have difficulty accessing the active site. Structure-based mutagenesis showed that substitution of Glu-280 and Arg-411 eliminates enzyme activity. In contrast, modification of other active site residues or of amino acids in the flexible active site loops has little effect, highlighting these regions as potential targets in designing an enzyme that will accept larger substrates.

  16. Crystal Structure of the Deglycating Enzyme Fructosamine Oxidase (Amadoriase II)

    SciTech Connect

    Collard, François; Zhang, Jianye; Nemet, Ina; Qanungo, Kaustubha R.; Monnier, Vincent M.; Yee, Vivien C.

    2009-01-12

    Fructosamine oxidases (FAOX) catalyze the oxidative deglycation of low molecular weight fructosamines (Amadori products). These proteins are of interest in developing an enzyme to deglycate proteins implicated in diabetic complications. We report here the crystal structures of FAOX-II from the fungi Aspergillus fumigatus, in free form and in complex with the inhibitor fructosyl-thioacetate, at 1.75 and 1.6{angstrom} resolution, respectively. FAOX-II is a two domain FAD-enzyme with an overall topology that is most similar to that of monomeric sarcosine oxidase. Active site residues Tyr-60, Arg-112 and Lys-368 bind the carboxylic portion of the fructosamine, whereas Glu-280 and Arg-411 bind the fructosyl portion. From structure-guided sequence comparison, Glu-280 was identified as a signature residue for FAOX activity. Two flexible surface loops become ordered upon binding of the inhibitor in a catalytic site that is about 12{angstrom} deep, providing an explanation for the very low activity of FAOX enzymes toward protein-bound fructosamines, which would have difficulty accessing the active site. Structure-based mutagenesis showed that substitution of Glu-280 and Arg-411 eliminates enzyme activity. In contrast, modification of other active site residues or of amino acids in the flexible active site loops has little effect, highlighting these regions as potential targets in designing an enzyme that will accept larger substrates.

  17. Genistein effect on xanthine oxidase activity.

    PubMed

    Sumbayev, V V

    2001-01-01

    Genistein was defined to be an allosteric xanthine oxidase inhibitor in the concentrations 0.1-4.0 microM and xanthine oxidase activator with superoxide scavenging activity in the concentrations 5.0 microM and higher. But the most effective allosteric binding with the highest affinity was observed in the genistein concentrations 0.1-1.0 microM. Intraperitoneum injections of genistein (500 micrograms/kg) during three days with the interval 24 hours decrease xanthine oxidase activity in the liver, lung and brain of the Vistar rats.

  18. Validation of EMP bounds

    SciTech Connect

    Warne, L.K.; Merewether, K.O.; Chen, K.C.; Jorgenson, R.E.; Morris, M.E.; Solberg, J.E.; Lewis, J.G.; Derr, W.

    1996-07-01

    Test data on canonical weapon-like fixtures are used to validate previously developed analytical bounding results. The test fixtures were constructed to simulate (but be slightly worse than) weapon ports of entry but have known geometries (and electrical points of contact). The exterior of the test fixtures exhibited exterior resonant enhancement of the incident fields at the ports of entry with magnitudes equal to those of weapon geometries. The interior consisted of loaded transmission lines adjusted to maximize received energy or voltage but incorporating practical weapon geometrical constraints. New analytical results are also presented for bounding the energies associated with multiple bolt joints and for bounding the exterior resonant enhancement of the exciting fields.

  19. Kinetic and ligand binding evidence for two heme A-based terminal oxidases in plasma membranes from Bacillus subtilis.

    PubMed

    Hill, B C; Vo, L; Albanese, J

    1993-02-15

    Detergent-solubilized plasma membranes from Bacillus subtilis have been characterized for their cytochrome oxidase content. Triton X-100-solubilized membranes show high O2 turnover with ascorbate plus TMPD. Reduced-oxidized difference spectroscopy of ascorbate-TMPD-reduced membranes reveals the presence of cytochrome c and cytochrome a. An additional, b-type cytochrome appears when the membranes are reduced with dithionite. Time-resolved difference spectra taken during reduction by ascorbate-TMPD reveal two kinetic forms of heme A-containing cytochromes. There is a high-turnover form that is rapidly reduced upon anaerobiosis, and a second type which is only slowly reduced upon anaerobiosis. The slowly reduced oxidase is distinguished by an alpha-band blue-shifted to 600 nm relative to the 603-nm position observed for high-turnover oxidase. Addition of CO to ascorbate-TMPD-reduced membranes gives a spectrum typical of ferrocytochrome a3-CO, and the intensity corresponds to the total ferrocytochrome a3 concentration. Photolysis of ascorbate-TMPD-reduced, CO-bound membranes indicates that both species are photosensitive with similar rates of recombination. Addition of CO to dithionite-reduced membranes shows an additional CO reactive center that has a spectrum characteristic of cytochrome o. Cyanide blocks complete reduction of high-turnover oxidase by ascorbate plus TMPD, but does not appear to effect slowly reduced oxidase. These results indicate the presence of two different types of cytochrome aa3 oxidase in plasma membranes of B. subtilis.

  20. Prokaryotic origins for the mitochondrial alternative oxidase and plastid terminal oxidase nuclear genes.

    PubMed

    Finnegan, Patrick M; Umbach, Ann L; Wilce, Jackie A

    2003-12-18

    The mitochondrial alternative oxidase is a diiron carboxylate quinol oxidase (Dox) found in plants and some fungi and protists, but not animals. The plastid terminal oxidase is distantly related to alternative oxidase and is most likely also a Dox protein. Database searches revealed that the alpha-proteobacterium Novosphingobium aromaticivorans and the cyanobacteria Nostoc sp. PCC7120, Synechococcus sp. WH8102 and Prochlorococcus marinus subsp. pastoris CCMP1378 each possess a Dox homolog. Each prokaryotic protein conforms to the current structural models of the Dox active site and phylogenetic analyses suggest that the eukaryotic Dox genes arose from an ancestral prokaryotic gene.

  1. Direct electron-transfer conduits constructed at the interface between multicopper oxidase and nanocrystalline semiconductive Fe oxides

    NASA Astrophysics Data System (ADS)

    Nakamura, Ryuhei; Kamiya, Kazuhide; Hashimoto, Kazuhito

    2010-10-01

    Herein, the electron-transfer reactions occurring at the interface between bilirubin oxidase (BOD) and nanocrystalline hematite (α-Fe 2O 3) were characterized. Cyclic voltammograms indicated that BOD has an affinity for hematite surfaces and establishes a direct electron-transfer (DET) conduit between the primary electron acceptor T1 site and the conduction band of α-Fe 2O 3. DET was also confirmed photo-electrochemically, as cathodic photocurrents were generated when a nanocomposite of BOD and α-Fe 2O 3 was illuminated under oxygenated conditions. A proline residue displayed a high-binding affinity for hematite surfaces and is therefore likely part of an orientation-controlled motif which serves to locate BOD at the T1 site at a suitable distance for DET to α-Fe 2O 3.

  2. REGULATION OF NADPH OXIDASES IN SKELETAL MUSCLE

    PubMed Central

    Ferreira, Leonardo F.; Laitano, Orlando

    2016-01-01

    The only known function of NAD(P)H oxidases is to produce reactive oxygen species (ROS). Skeletal muscles express three isoforms of NAD(P)H oxidases (Nox1, Nox2, and Nox4) that have been identified as critical modulators of redox homeostasis. Nox2 acts as the main source of skeletal muscle ROS during contractions, participates insulin signaling and glucose transport, and mediates the myocyte response to osmotic stress. Nox2 and Nox4 contribute to skeletal muscle abnormalities elicited by angiotensin II, muscular dystrophy, heart failure, and high fat diet. Our review addresses the expression and regulation of NAD(P)H oxidases with emphasis on aspects that are relevant to skeletal muscle. We also summarize: i) the most widely used NAD(P)H oxidases activity assays and inhibitors, and ii) studies that have defined Nox enzymes as protagonists of skeletal muscle redox homeostasis in a variety of health and disease conditions. PMID:27184955

  3. Activation of polyphenol oxidase of chloroplasts.

    PubMed

    Tolbert, N E

    1973-02-01

    Polyphenol oxidase of leaves is located mainly in chloroplasts isolated by differential or sucrose density gradient centrifugation. This activity is part of the lamellar structure that is not lost on repeated washing of the plastids. The oxidase activity was stable during prolonged storage of the particles at 4 C or -18 C. The Km (dihydroxyphenylalanine) for spinach leaf polyphenol oxidase was 7 mm by a spectrophotometric assay and 2 mm by the manometric assay. Polyphenol oxidase activity in the leaf peroxisomal fraction, after isopycnic centrifugation on a linear sucrose gradient, did not coincide with the peroxisomal enzymes but was attributed to proplastids at nearly the same specific density.Plants were grouped by the latency properties for polyphenol oxidase in their isolated chloroplasts. In a group including spinach, Swiss chard, and beet leaves the plastids immediately after preparation from fresh leaves required a small amount of light for maximal rates of oxidation of dihydroxyphenylalanine. Polyphenol oxidase activity in the dark or light increased many fold during aging of these chloroplasts for 1 to 5 days. Soluble polyphenol oxidase of the cytoplasm was not so stimulated. Chloroplasts prepared from stored leaves were also much more active than from fresh leaves. Maximum rates of dihydroxyphenylalanine oxidation were 2 to 6 mmoles x mg(-1) chlorophyll x hr(-1). Equal stimulation of latent polyphenol oxidase in fresh or aged chloroplasts in this group was obtained by either light, an aged trypsin digest, 3-(4-chlorophenyl)-1, 1-dimethylurea, or antimycin A. A variety of other treatments did not activate or had little effect on the oxidase, including various peptides, salts, detergents, and other proteolytic enzymes.Activation of latent polyphenol oxidase in spinach chloroplasts by trypsin amounted to as much as 30-fold. The trypsin activation occurred even after the trypsin had been treated with 10% trichloroacetic acid, 1.0 n HCl or boiled for 30

  4. Genetics Home Reference: cytochrome c oxidase deficiency

    MedlinePlus

    ... DNA in specialized structures in the cell called mitochondria . This type of DNA is known as mitochondrial ... oxidase deficiency are involved in energy production in mitochondria through a process called oxidative phosphorylation . The gene ...

  5. Activation of Polyphenol Oxidase of Chloroplasts 1

    PubMed Central

    Tolbert, N. E.

    1973-01-01

    Polyphenol oxidase of leaves is located mainly in chloroplasts isolated by differential or sucrose density gradient centrifugation. This activity is part of the lamellar structure that is not lost on repeated washing of the plastids. The oxidase activity was stable during prolonged storage of the particles at 4 C or —18 C. The Km (dihydroxyphenylalanine) for spinach leaf polyphenol oxidase was 7 mm by a spectrophotometric assay and 2 mm by the manometric assay. Polyphenol oxidase activity in the leaf peroxisomal fraction, after isopycnic centrifugation on a linear sucrose gradient, did not coincide with the peroxisomal enzymes but was attributed to proplastids at nearly the same specific density. Plants were grouped by the latency properties for polyphenol oxidase in their isolated chloroplasts. In a group including spinach, Swiss chard, and beet leaves the plastids immediately after preparation from fresh leaves required a small amount of light for maximal rates of oxidation of dihydroxyphenylalanine. Polyphenol oxidase activity in the dark or light increased many fold during aging of these chloroplasts for 1 to 5 days. Soluble polyphenol oxidase of the cytoplasm was not so stimulated. Chloroplasts prepared from stored leaves were also much more active than from fresh leaves. Maximum rates of dihydroxyphenylalanine oxidation were 2 to 6 mmoles × mg−1 chlorophyll × hr−1. Equal stimulation of latent polyphenol oxidase in fresh or aged chloroplasts in this group was obtained by either light, an aged trypsin digest, 3-(4-chlorophenyl)-1, 1-dimethylurea, or antimycin A. A variety of other treatments did not activate or had little effect on the oxidase, including various peptides, salts, detergents, and other proteolytic enzymes. Activation of latent polyphenol oxidase in spinach chloroplasts by trypsin amounted to as much as 30-fold. The trypsin activation occurred even after the trypsin had been treated with 10% trichloroacetic acid, 1.0 n HCl or boiled for 30

  6. Bilirubin - blood

    MedlinePlus

    ... Gastroenterology. In: Rennie JM, ed. Rennie and Robsertson's Textbook of Neonatology. 5th ed. Philadelphia, PA: Elsevier; 2012:chap 29. Pratt DS. Liver chemistry and function tests. In: Feldman M, Friedman LS, ...

  7. Affinity of human serum albumin for bilirubin varies with albumin concentration and buffer composition: results of a novel ultrafiltration method.

    PubMed

    Weisiger, R A; Ostrow, J D; Koehler, R K; Webster, C C; Mukerjee, P; Pascolo, L; Tiribelli, C

    2001-08-10

    Albumin binding is a crucial determinant of bilirubin clearance in health and bilirubin toxicity in certain disease states. However, prior attempts to measure the affinity of albumin for bilirubin have yielded highly variable results, reflecting both differing conditions and the confounding influence of impurities. We therefore have devised a method based on serial ultrafiltration that successively removes impurities in [(14)C]bilirubin until a stable binding affinity is achieved, and then we used it to assess the effect of albumin concentration and buffer composition on binding. The apparent binding affinity of human serum albumin for [(14)C]bilirubin was strongly dependent on assay conditions, falling from (5.09 +/- 0.24) x 10(7) liters/mol at lower albumin concentrations (15 microm) to (0.54 +/- 0.05) x 10(7) liters/mol at higher albumin concentrations (300 microm). To determine whether radioactive impurities were responsible for this change, we estimated impurities in the stock bilirubin using a novel modeling approach and found them to be 0.11-0.13%. Formation of new impurities during the study and their affinity for albumin were also estimated. After correction for impurities, the binding affinity remained heavily dependent on the albumin concentration (range (5.37 +/- 0.26) x 10(7) liters/mol to (0.65 +/- 0.03) x 10(7) liters/mol). Affinities decreased by about half in the presence of chloride (50 mm). Thus, the affinity of human albumin for bilirubin is not constant, but varies with both albumin concentration and buffer composition. Binding may be considerably less avid at physiological albumin concentrations than previously believed.

  8. Reductive trapping of substrate to bovine plasma amine oxidase

    SciTech Connect

    Hartmann, C.; Klinman, J.P.

    1987-01-25

    Plasma amine oxidases catalyze the oxidative deamination of amines to aldehydes, followed by a 2e- reduction of O/sub 2/ to H/sub 2/O/sub 2/. Pyrroloquinoline quinone (PQQ), previously believed to be restricted to prokaryotes, has recently been proposed to be the cofactor undergoing reduction in the first half-reaction of bovine plasma amine oxidase (Ameyama, M., Hayashi, U., Matsushita, K., Shinagawa, E., and Adachi, O. (1984) Agric. Biol. Chem. 48, 561-565; Lobenstein-Verbeek, C. L., Jongejan, J. A., Frank, J., and Duine, J. A. (1984) FEBS Lett. 170, 305-309). This result is unexpected, since model studies with PQQ implicate Schiff's base formation between a reactive carbonyl and substrates, whereas experiments with bovine plasma amine oxidase have failed to provide evidence for a carbonyl cofactor. We have, therefore, re-examined putative adducts between substrate and enzyme-bound cofactor, employing a combination of (/sup 14/C)benzylamine and (/sup 3/H)NaCNBH/sub 3/. The use of the relatively weak reductant, NaCNBH/sub 3/, affords Schiff's base specificity and permits the study of enzyme below pH 7.0. As we show, enzyme can only be inactivated by NaCNBH/sub 3/ in the presence of substrate, leading to the incorporation of 1 mol of (/sup 14/C)benzylamine/mol of enzyme subunit at complete inactivation. By contrast, we are unable to detect any labeling with (/sup 3/H)NaCNBH/sub 3/, analogous to an earlier study with (/sup 3/H)NaCNBH/sub 4/ (Suva, R. H., and Abeles, R. H. (1978) Biochemistry 17, 3538-3545). We conclude, first, that our inability to obtain adducts containing both carbon 14 and tritium rules out the reductive trapping either of amine substrate with pyridoxal phosphate or of aldehyde product with a lysyl side chain and, second, that the observed pattern of labeling is fully consistent with the presence of PQQ at the active site of bovine plasma amine oxidase.

  9. Disparate Pathways for the Biogenesis of Cytochrome Oxidases in Bradyrhizobium japonicum*

    PubMed Central

    Bühler, Doris; Rossmann, Reinhild; Landolt, Sarah; Balsiger, Sylvia; Fischer, Hans-Martin; Hennecke, Hauke

    2010-01-01

    This work addresses the biogenesis of heme-copper terminal oxidases in Bradyrhizobium japonicum, the nitrogen-fixing root nodule symbiont of soybean. B. japonicum has four quinol oxidases and four cytochrome oxidases. The latter include the aa3- and cbb3-type oxidases. Although both have a CuB center in subunit I, the subunit II proteins differ in having either a CuA center (in aa3) or a covalently bound heme c (in cbb3). Two biogenesis factors were genetically studied here, the periplasmically exposed CoxG and ScoI proteins, which are the respective homologs of the mitochondrial copper-trafficking chaperones Cox11 and Sco1 for the formation of the CuB center in subunit I and the CuA center in subunit II of cytochrome aa3. We could demonstrate copper binding to ScoI in vitro, a process for which the thiols of cysteine residues 74 and 78 in the ScoI polypeptide were shown to be essential. Knock-out mutations in the B. japonicum coxG and scoI genes led to loss of cytochrome aa3 assembly and activity in the cytoplasmic membrane, whereas the cbb3-type cytochrome oxidase apparently remained unaffected. This suggests that subunit I of the cbb3-type oxidase obtains its copper cofactor via a different pathway than cytochrome aa3. In contrast to the coxG mutation, the scoI mutation caused a decreased symbiotic nitrogen fixation activity. We hypothesize that a periplasmic B. japonicum protein other than any of the identified CuA proteins depends on ScoI and is required for an effective symbiosis. PMID:20335176

  10. Disparate pathways for the biogenesis of cytochrome oxidases in Bradyrhizobium japonicum.

    PubMed

    Bühler, Doris; Rossmann, Reinhild; Landolt, Sarah; Balsiger, Sylvia; Fischer, Hans-Martin; Hennecke, Hauke

    2010-05-21

    This work addresses the biogenesis of heme-copper terminal oxidases in Bradyrhizobium japonicum, the nitrogen-fixing root nodule symbiont of soybean. B. japonicum has four quinol oxidases and four cytochrome oxidases. The latter include the aa(3)- and cbb(3)-type oxidases. Although both have a Cu(B) center in subunit I, the subunit II proteins differ in having either a Cu(A) center (in aa(3)) or a covalently bound heme c (in cbb(3)). Two biogenesis factors were genetically studied here, the periplasmically exposed CoxG and ScoI proteins, which are the respective homologs of the mitochondrial copper-trafficking chaperones Cox11 and Sco1 for the formation of the Cu(B) center in subunit I and the Cu(A) center in subunit II of cytochrome aa(3). We could demonstrate copper binding to ScoI in vitro, a process for which the thiols of cysteine residues 74 and 78 in the ScoI polypeptide were shown to be essential. Knock-out mutations in the B. japonicum coxG and scoI genes led to loss of cytochrome aa(3) assembly and activity in the cytoplasmic membrane, whereas the cbb(3)-type cytochrome oxidase apparently remained unaffected. This suggests that subunit I of the cbb(3)-type oxidase obtains its copper cofactor via a different pathway than cytochrome aa(3). In contrast to the coxG mutation, the scoI mutation caused a decreased symbiotic nitrogen fixation activity. We hypothesize that a periplasmic B. japonicum protein other than any of the identified Cu(A) proteins depends on ScoI and is required for an effective symbiosis.

  11. Patched Skin Bilirubin Assay to Monitor Neonates Born Extremely Preterm Undergoing Phototherapy.

    PubMed

    De Luca, Daniele; Dell'Orto, Valentina

    2017-09-01

    To verify the reliability and safety of transcutaneous bilirubin (TcB) measurements in patched skin areas in neonates born extremely preterm under phototherapy. Sixty neonates (<30 weeks' gestation) receiving phototherapy were enrolled and TcB was measured via a second-generation transcutaneous bilirubinometer in patched skin areas (of at least 2.5 cm diameter). Total serum bilirubin (TSB), lactate, pH, hemoglobin, and skin temperature were measured within 10 minutes of the TcB assay. Clinicians were blinded to TcB values, and clinical decisions about phototherapy were made with the TSB measurement only. TcB and TSB significantly were correlated (r = 0.84; P <.001), even after adjustment for hemoglobin, pH, lactate, gestational and postnatal age (standardized β = 0.8; P <.001; adjusted R(2) = 0.75), or treatment duration (standardized β = 0.8; P <.001; adjusted R(2) = 0.7). When the Bland-Altman analysis was used, TcB overestimated TSB at high values (mean difference TSB - TcB: -2.8 [2.4] mg/dL). If clinicians used the TcB only, no neonate would have had phototherapy stopped prematurely, and 21 (35%) would have continued phototherapy when it could have been stopped. The correlation between TSB and TcB (measured in patched skin areas) was comparable with that obtained in more mature neonates, and it was not influenced by clinical variables or factors affecting skin bilirubin passage. TcB overestimated TSB, and this may expose infants born preterm to unnecessary phototherapy, although it could spare approximately 65% of TSB assays. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Azide inhibition of urate oxidase.

    PubMed

    Gabison, Laure; Colloc'h, Nathalie; Prangé, Thierry

    2014-07-01

    The inhibition of urate oxidase (UOX) by azide was investigated by X-ray diffraction techniques and compared with cyanide inhibition. Two well characterized sites for reagents are present in the enzyme: the dioxygen site and the substrate-binding site. To examine the selectivity of these sites towards azide inhibition, several crystallization conditions were developed. UOX was co-crystallized with azide (N3) in the presence or absence of either uric acid (UA, the natural substrate) or 8-azaxanthine (8AZA, a competitive inhibitor). In a second set of experiments, previously grown orthorhombic crystals of the UOX-UA or UOX-8AZA complexes were soaked in sodium azide solutions. In a third set of experiments, orthorhombic crystals of UOX with the exchangeable ligand 8-nitroxanthine (8NXN) were soaked in a solution containing uric acid and azide simultaneously (competitive soaking). In all assays, the soaking periods were either short (a few hours) or long (one or two months). These different experimental conditions showed that one or other of the sites, or the two sites together, could be inhibited. This also demonstrated that azide not only competes with dioxygen as cyanide does but also competes with the substrate for its enzymatic site. A model in agreement with experimental data would be an azide in equilibrium between two sites, kinetically in favour of the dioxygen site and thermodynamically in favour of the substrate-binding site.

  13. Azide inhibition of urate oxidase

    PubMed Central

    Gabison, Laure; Colloc’h, Nathalie; Prangé, Thierry

    2014-01-01

    The inhibition of urate oxidase (UOX) by azide was investigated by X-ray diffraction techniques and compared with cyanide inhibition. Two well characterized sites for reagents are present in the enzyme: the dioxygen site and the substrate-binding site. To examine the selectivity of these sites towards azide inhibition, several crystallization conditions were developed. UOX was co-crystallized with azide (N3) in the presence or absence of either uric acid (UA, the natural substrate) or 8-azaxanthine (8AZA, a competitive inhibitor). In a second set of experiments, previously grown orthorhombic crystals of the UOX–UA or UOX–8AZA complexes were soaked in sodium azide solutions. In a third set of experiments, orthorhombic crystals of UOX with the exchangeable ligand 8-nitroxanthine (8NXN) were soaked in a solution containing uric acid and azide simultaneously (competitive soaking). In all assays, the soaking periods were either short (a few hours) or long (one or two months). These different experimental conditions showed that one or other of the sites, or the two sites together, could be inhibited. This also demonstrated that azide not only competes with dioxygen as cyanide does but also competes with the substrate for its enzymatic site. A model in agreement with experimental data would be an azide in equilibrium between two sites, kinetically in favour of the dioxygen site and thermodynamically in favour of the substrate-binding site. PMID:25005084

  14. A Conserved Amphipathic Ligand Binding Region Influences K-Path Dependent Activity of Cytochrome c Oxidase

    PubMed Central

    Hiser, Carrie; Buhrow, Leann; Liu, Jian; Kuhn, Leslie; Ferguson-Miller, Shelagh

    2013-01-01

    A conserved, crystallographically-defined bile acid binding site was originally identified in the membrane domain of mammalian and bacterial cytochrome c oxidase (CcO). Current studies show other amphipathic molecules including detergents, fatty acids, steroids, and porphyrins bind to this site and affect the already 50% inhibited activity of the E101A mutant of Rhodobacter sphaeroides CcO, as well as altering the activity of wildtype and bovine enzymes. Dodecyl maltoside, Triton X100, C12E8, lysophophatidylcholine and CHOBIMALT detergents further inhibit RsCcO E101A, with lesser inhibition observed in wildtype. The detergent inhibition is overcome in the presence of μM concentrations of steroids and porphyrin analogs including deoxycholate, cholesteryl hemisuccinate, bilirubin, and protoporphyrin IX. In addition to alleviating detergent inhibition, amphipathic carboxylates including arachidonic, docosahexanoic, and phytanic acids stimulate the activity of E101A to wildtype levels by providing the missing carboxyl group. Computational modeling of dodecyl maltoside, bilirubin, and protoporphyrin IX into the conserved steroid site shows energetically favorable binding modes for these ligands and suggests that a groove at the interface of subunit I and II, including the entrance to the K-path and helix VIII of subunit I, mediates the observed competitive ligand interactions involving two overlapping sites. Spectral analysis indicates that ligand binding to this region affects CcO activity by altering the K path dependent electron transfer equilibrium between heme a and heme a3. The high affinity and specificity of a number of compounds for this region, and its conservation and impact on CcO activity, support its physiological significance. PMID:23351100

  15. Computing Graphical Confidence Bounds

    NASA Technical Reports Server (NTRS)

    Mezzacappa, M. A.

    1983-01-01

    Approximation for graphical confidence bounds is simple enough to run on programmable calculator. Approximation is used in lieu of numerical tables not always available, and exact calculations, which often require rather sizable computer resources. Approximation verified for collection of up to 50 data points. Method used to analyze tile-strength data on Space Shuttle thermal-protection system.

  16. Born Level Bound States

    NASA Astrophysics Data System (ADS)

    Hoyer, Paul

    2017-05-01

    Bound state poles in the S-matrix of perturbative QED are generated by the divergence of the expansion in α . The perturbative corrections are necessarily singular when expanding around free, {O}( α ^0 ) in and out states that have no overlap with finite-sized atomic wave functions. Nevertheless, measurables such as binding energies do have well-behaved expansions in powers of α (and log α ). It is desirable to formulate the concept of "lowest order" for gauge theory bound states such that higher order corrections vanish in the α → 0 limit. This may allow to determine a lowest order term for QCD hadrons which incorporates essential features such as confinement and chiral symmetry breaking, and thus can serve as the starting point of a useful perturbative expansion. I discuss a "Born" (no loop, lowest order in \\hbar ) approximation. Born level states are bound by gauge fields which satisfy the classical field equations. Gauss' law determines a distinct field A^0({\\varvec{x}}) for each instantaneous position of the charges. A Poincaré covariant boundary condition for the gluon field leads to a confining potential for q\\bar{q} and qqq states. In frames where the bound state is in motion the classical gauge field is obtained by a Lorentz boost of the rest frame field.

  17. Computing Graphical Confidence Bounds

    NASA Technical Reports Server (NTRS)

    Mezzacappa, M. A.

    1983-01-01

    Approximation for graphical confidence bounds is simple enough to run on programmable calculator. Approximation is used in lieu of numerical tables not always available, and exact calculations, which often require rather sizable computer resources. Approximation verified for collection of up to 50 data points. Method used to analyze tile-strength data on Space Shuttle thermal-protection system.

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

    PubMed

    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

  19. Genome-wide association of serum bilirubin levels in Korean population.

    PubMed

    Kang, Tae-Wook; Kim, Hee-Jin; Ju, Hyoungseok; Kim, Jeong-Hwan; Jeon, Yeo-Jin; Lee, Han-Chul; Kim, Ka-Kyung; Kim, Jong-Won; Lee, Siwoo; Kim, Jong Yeol; Kim, Seon-Young; Kim, Yong Sung

    2010-09-15

    A large-scale, genome-wide association study was performed to identify genetic variations influencing serum bilirubin levels using 8841 Korean individuals. Significant associations were observed at UGT1A1 (rs11891311, P = 4.78 x 10(-148)) and SLCO1B3 (rs2417940, P = 1.03 x 10(-17)), which are two previously identified loci. The two single-nucleotide polymorphisms (SNPs) were replicated (rs11891311, P = 3.18 x 10(-15)) or marginally significant (rs2417940, P = 8.56 x 10(-4)) in an independent cohort of 1096 individuals. In a conditional analysis adjusted for the top UGT1A1 variant (rs11891311), another variant in UGT1A1 (rs4148323, P = 1.22 x 10(-121)) remained significant; this suggests that in UGT1A1 at least two independent genetic variations influence the bilirubin levels in the Korean population. The protein coding variant rs4148323, which is monomorphic in European-derived populations, may be specifically associated with serum bilirubin levels in Asians (P = 2.56 x 10(-70)). The SLCO1B3 variant (rs2417940, P = 1.67 x 10(-18)) remained significant in a conditional analysis for the top UGT1A1 variant. Interestingly, there were significant differences in the associated variations of SLCO1B3 between Koreans and European-derived populations. While the variant rs2417940 at intron 7 of SLCO1B3 was more significantly associated in Koreans, variants rs17680137 (P = 0.584) and rs2117032 (P = 2.76 x 10(-5)), two of the top-ranked SNPs in European-derived populations, did not reach the genome-wide significance level. Also, variants in SLCO1B1 did not reach genome-wide significance in Koreans. Our result supports the idea that there are considerable ethnic differences in genetic association of bilirubin levels between Koreans and European-derived populations.

  20. Forage polyphenol oxidase and ruminant livestock nutrition

    PubMed Central

    Lee, Michael R. F.

    2014-01-01

    Polyphenol oxidase (PPO) is predominately associated with the detrimental effect of browning fruit and vegetables, however, interest within PPO containing forage crops (crops to be fed to animals) has grown since the browning reaction was associated with reduced nitrogen (N) losses in silo and the rumen. The reduction in protein breakdown in silo of red clover (high PPO forage) increased the quality of protein, improving N-use efficiency [feed N into product N (e.g., Milk): NUE] when fed to ruminants. A further benefit of red clover silage feeding is a significant reduction in lipolysis (cleaving of glycerol-based lipid) in silo and an increase in the deposition of beneficial C18 polyunsaturated fatty acid (PUFA) in animal products, which has also been linked to PPO activity. PPOs protection of plant protein and glycerol based-PUFA in silo is related to the deactivation of plant proteases and lipases. This deactivation occurs through PPO catalyzing the conversion of diphenols to quinones which bind with cellular nucleophiles such as protein reforming a protein-bound phenol (PBP). If the protein is an enzyme (e.g., protease or lipase) the complexing denatures the enzyme. However, PPO is inactive in the anaerobic rumen and therefore any subsequent protection of plant protein and glycerol based-PUFA in the rumen must be as a result of events that occurred to the forage pre-ingestion. Reduced activity of plant proteases and lipases would have little effect on NUE and glycerol based-PUFA in the rumen due to the greater concentration of rumen microbial proteases and lipases. The mechanism for PPOs protection of plant protein in the rumen is a consequence of complexing plant protein, rather than protease deactivation per se. These complexed proteins reduce protein digestibility in the rumen and subsequently increase undegraded dietary protein flow to the small intestine. The mechanism for protecting glycerol-based PUFA has yet to be fully elucidated but may be associated

  1. The Elusive Third Subunit IIa of the Bacterial B-Type Oxidases: The Enzyme from the Hyperthermophile Aquifex aeolicus

    PubMed Central

    Prunetti, Laurence; Brugna, Myriam; Lebrun, Régine; Giudici-Orticoni, Marie-Thérèse; Guiral, Marianne

    2011-01-01

    The reduction of molecular oxygen to water is catalyzed by complicated membrane-bound metallo-enzymes containing variable numbers of subunits, called cytochrome c oxidases or quinol oxidases. We previously described the cytochrome c oxidase II from the hyperthermophilic bacterium Aquifex aeolicus as a ba3-type two-subunit (subunits I and II) enzyme and showed that it is included in a supercomplex involved in the sulfide-oxygen respiration pathway. It belongs to the B-family of the heme-copper oxidases, enzymes that are far less studied than the ones from family A. Here, we describe the presence in this enzyme of an additional transmembrane helix “subunit IIa”, which is composed of 41 amino acid residues with a measured molecular mass of 5105 Da. Moreover, we show that subunit II, as expected, is in fact longer than the originally annotated protein (from the genome) and contains a transmembrane domain. Using Aquifex aeolicus genomic sequence analyses, N-terminal sequencing, peptide mass fingerprinting and mass spectrometry analysis on entire subunits, we conclude that the B-type enzyme from this bacterium is a three-subunit complex. It is composed of subunit I (encoded by coxA2) of 59000 Da, subunit II (encoded by coxB2) of 16700 Da and subunit IIa which contain 12, 1 and 1 transmembrane helices respectively. A structural model indicates that the structural organization of the complex strongly resembles that of the ba3 cytochrome c oxidase from the bacterium Thermus thermophilus, the IIa helical subunit being structurally the lacking N-terminal transmembrane helix of subunit II present in the A-type oxidases. Analysis of the genomic context of genes encoding oxidases indicates that this third subunit is present in many of the bacterial oxidases from B-family, enzymes that have been described as two-subunit complexes. PMID:21738733

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

    PubMed Central

    Zhou, Jin; Tracy, Timothy S.

    2011-01-01

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

  3. The levels of bilirubin may be related to an inflammatory condition in patients with coronary heart disease.

    PubMed

    Greabu, M; Olinescu, R; Kummerow, F A; Crocnan, D O

    2001-01-01

    In agreement with previous reports, we found that the bilirubin level is significantly lower in the blood of patients with coronary heart disease (CHD) than in age and sex matched controls. However, we found that the level of bilirubin in the blood seemed to be an age-dependent phenomenon and closely related to the activation of leukocytes. In 1,000 cardiac catheterised patients from Urbana, USA suffering from CHD, the level of blood bilirubin was found to be lower than in age and sex-matched controls. The same results were obtained on 300 patients with acute ischemia from three hospitals from Bucharest, Romania. The activation of polymorphonuclear leukocytes increased in the catheterised patients, as well in Romanian patients. An activation of leukocytes triggered by a chronic inflammatory process may increase the lysis of erythrocytes. The erythrocytes of patients with 100% stenosis exhibited a higher rate of in vitro lysis in the presence of activated leukocytes and homocysteine. The increased hemolysis may trigger the activation and removal of the resulting bilirubin from blood. Such a mechanism may depend on the liver clearing function. This function was decreased in catheterized patients over 60 years of age, but had accelerated in younger patients. An individual variation in liver function may explain the widespread bilirubin levels in the blood of patients suffering from CHD.

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

    PubMed Central

    Du, Min; Zhang, Shanshan; Xiao, Lin; Xu, Yanyan; Liu, Peiyi; Tang, Yuhan; Wei, Sheng; Xing, Mingyou; Miao, Xiaoping; Yao, Ping

    2016-01-01

    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. PMID:27941693

  5. Design of experiments and principal component analysis as approaches for enhancing performance of gas-diffusional air-breathing bilirubin oxidase cathode

    NASA Astrophysics Data System (ADS)

    Babanova, Sofia; Artyushkova, Kateryna; Ulyanova, Yevgenia; Singhal, Sameer; Atanassov, Plamen

    2014-01-01

    Two statistical methods, design of experiments (DOE) and principal component analysis (PCA) are employed to investigate and improve performance of air-breathing gas-diffusional enzymatic electrodes. DOE is utilized as a tool for systematic organization and evaluation of various factors affecting the performance of the composite system. Based on the results from the DOE, an improved cathode is constructed. The current density generated utilizing the improved cathode (755 ± 39 μA cm-2 at 0.3 V vs. Ag/AgCl) is 2-5 times higher than the highest current density previously achieved. Three major factors contributing to the cathode performance are identified: the amount of enzyme, the volume of phosphate buffer used to immobilize the enzyme, and the thickness of the gas-diffusion layer (GDL). PCA is applied as an independent confirmation tool to support conclusions made by DOE and to visualize the contribution of factors in individual cathode configurations.

  6. 5,5-Dithiobis(2-nitrobenzoic acid) pyrene derivative-carbon nanotube electrodes for NADH electrooxidation and oriented immobilization of multicopper oxidases for the development of glucose/O2 biofuel cells.

    PubMed

    Giroud, Fabien; Sawada, Koichi; Taya, Masahito; Cosnier, Serge

    2017-01-15

    We report the functionalization of multi-walled carbon nanotubes (MWCNTs) electrodes by a bifunctional nitroaromatic molecule accomplished via π-π interactions of a pyrene derivative. DTNB (5,5'-dithiobis(2-nitrobenzoic acid)) has the particularity to possess both electroactivable nitro groups and negatively charged carboxylic groups. The integration of the DTNB-modified MWCNTs was evaluated for different bioelectrocatalytic systems. The immobilized DTNB-based electrodes showed electrocatalytic activity toward the oxidation of the reduced form of nicotinamide adenine dinucleotide (NADH) with low overpotential of -0.09V vs Ag/AgCl at neutral pH. Glucose dehydrogenase was successfully immobilized at the surface of DTNB-based electrodes and, in the presence of NAD(+), the resulting bioelectrode achieved efficient glucose oxidation with high current densities of 2.03mAcm(-2). On the other hand, the aromatic structure and the negatively charged nature of the DTNB provoked orientation of both laccase and bilirubin oxidase onto the electrode, which enhanced their ability to undergo a direct electron transfer for oxygen reduction. Due to the proper orientation, low overpotentials were obtained (ca. 0.6V vs Ag/AgCl) and high electrocatalytic currents of about 3.5mAcm(-)(2) were recorded at neutral pH in O2 saturated conditions for bilirubin oxidase electrodes. The combination of these bioanodes and bilirubin oxidase biocathodes provided glucose/O2 enzymatic biofuel cells (EBFC) exhibiting an open-circuit potential of 0.640V, with an associated maximum current density of 2.10mAcm(-)(2). Moreover, the fuel cell delivered a maximum power density of 0.50mWcm(-)(2) at 0.36 V.

  7. Self-assembly of aqueous bilirubin ditaurate, a natural conjugated bile pigment, to contraposing enantiomeric dimers and M(-) and P(+) tetramers and their selective hydrophilic disaggregation by monomers and micelles of bile salts.

    PubMed

    Neubrand, Michael W; Carey, Martin C; Laue, Thomas M

    2015-02-24

    The solution behavior of bilirubin ditaurate (BDT), the first naturally occurring conjugated bile pigment to be physically and chemically characterized, was assessed in aqueous solution and in monomeric and micellar solutions of common taurine-conjugated bile salts (BS). Analytical ultracentrifugation revealed that BDT self-associates in monomer-dimer equilibria between 1 and 500 μM, forming limiting tetramers at low millimolar concentrations. Self-association was enthalpically driven with ΔG values of ≈5 kcal/mol, suggesting strong hydrophobic interactions. Added NaCl and decreases in temperature shifted the oligomerization to lower BDT concentrations. On the basis of circular dichroism spectra and the limiting size of the self-aggregates, we infer that the tetramers are composed of 2P(+) and 2M(-) enantiomeric BDT pairs in "ridge-tile" conformations interacting in a "double-bookend" structure. With added monomeric BS, blue shifts in the UV-vis spectra and tight isosbestic points revealed that BDT/BS heterodimers form, followed by BDT "decorating" BS micelles mostly via hydrophilic interactions. Conformational enantiomerism, fluorescence intensities, and anisotropy, as well as resistance of the hybrid particles to disaggregation in 6 M urea, suggested that two or three hydrogen-bonding sites bound BDT monomers to the hydroxyl groups of BS, possibly via pyrrole-π-orbital-OH interactions. BDT stabilized these interactions by enveloping the BS in its "ridge-tile" pincers with variable strain that maximized van der Waals interactions. Possibly because the BDT molecule becomes highly strained with BS subtending a 7β-hydroxyl group, BDT became totally resistant to oxidation in air. This work predicts that, because of BS dissolution of the BDT self-aggregates, BS/bilirubin hybrid particles, which are stabilized hydrophilically, are likely to be the dominant mode of transport for all conjugated bilirubins in bile.

  8. Hace1 controls ROS generation of vertebrate Rac1-dependent NADPH oxidase complexes

    PubMed Central

    Daugaard, Mads; Nitsch, Roberto; Razaghi, Babak; McDonald, Lindsay; Jarrar, Ameer; Torrino, Stéphanie; Castillo-Lluva, Sonia; Rotblat, Barak; Li, Liheng; Malliri, Angeliki; Lemichez, Emmanuel; Mettouchi, Amel; Berman, Jason N.; Penninger, Josef M.; Sorensen, Poul H.

    2013-01-01

    The Hace1-HECT E3 ligase is a tumor suppressor that ubiquitylates the activated GTP-bound form of the Rho family GTPase Rac1, leading to Rac1 proteasomal degradation. Here we show that, in vertebrates, Hace1 targets Rac1 for degradation when Rac1 is localized to the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase holoenzyme. This event blocks de novo reactive oxygen species generation by Rac1-dependent NADPH oxidases, and thereby confers cellular protection from reactive oxygen species-induced DNA damage and cyclin D1-driven hyper-proliferation. Genetic inactivation of Hace1 in mice or zebrafish, as well as Hace1 loss in human tumor cell lines or primary murine or human tumors, leads to chronic NADPH oxidase-dependent reactive oxygen species elevation, DNA damage responses and enhanced cyclin D1 expression. Our data reveal a conserved ubiquitin-dependent molecular mechanism that controls the activity of Rac1-dependent NADPH oxidase complexes, and thus constitutes the first known example of a tumor suppressor protein that directly regulates reactive oxygen species production in vertebrates. PMID:23864022

  9. Nonhematopoietic NADPH oxidase regulation of lung eosinophilia and airway hyperresponsiveness in experimentally induced asthma

    PubMed Central

    Abdala-Valencia, Hiam; Earwood, Julie; Bansal, Shelly; Jansen, Michael; Babcock, George; Garvy, Beth; Wills-Karp, Marsha; Cook-Mills, Joan M.

    2009-01-01

    Pulmonary eosinophilia is one of the most consistent hallmarks of asthma. Infiltration of eosinophils into the lung in experimental asthma is dependent on the adhesion molecule vascular cell adhesion molecule-1 (VCAM-1) on endothelial cells. Ligation of VCAM-1 activates endothelial cell NADPH oxidase, which is required for VCAM-1-dependent leukocyte migration in vitro. To examine whether endothelial-derived NADPH oxidase modulates eosinophil recruitment in vivo, mice deficient in NADPH oxidase (CYBB mice) were irradiated and received wild-type hematopoietic cells to generate chimeric CYBB mice. In response to ovalbumin (OVA) challenge, the chimeric CYBB mice had increased numbers of eosinophils bound to the endothelium as well as reduced eosinophilia in the lung tissue and bronchoalveolar lavage. This occurred independent of changes in VCAM-1 expression, cytokine/chemokine levels (IL-5, IL-10, IL-13, IFNγ, or eotaxin), or numbers of T cells, neutrophils, or mononuclear cells in the lavage fluids or lung tissue of OVA-challenged mice. Importantly, the OVA-challenged chimeric CYBB mice had reduced airway hyperresponsiveness (AHR). The AHR in OVA-challenged chimeric CYBB mice was restored by bypassing the endothelium with intratracheal administration of eosinophils. These data suggest that VCAM-1 induction of NADPH oxidase in the endothelium is necessary for the eosinophil recruitment during allergic inflammation. Moreover, these studies provide a basis for targeting VCAM-1-dependent signaling pathways in asthma therapies. PMID:17293377

  10. Effects of aluminum chloride on serum proteins, bilirubin, and hepatic trace elements in chickens.

    PubMed

    Wang, Ben; Zhu, Yanzhu; Zhang, Hongling; Liu, Liming; Li, Guojiang; Song, Yongli; Li, Yanfei

    2016-09-01

    The aim of this study was to reveal the effects of aluminum chloride (AlCl3) on the hepatic metabolism function and trace elements' distribution. Two hundred healthy male chickens (1 day old) were intraperitoneally administered with AlCl3 (0, 18.31, 27.47, and 36.62 mg kg(-1) day(-1) of Al(3+)) consecutively for 3 days. Then the chickens were allowed to rest for 1 day. The cycle lasted four days. The cycle was repeated 15 times (60 days). The contents of serum total protein (TP), albumin (ALB), total bilirubin (TBI), direct bilirubin (DBI), hepatic aluminum (Al), copper (Cu), iron (Fe), and zinc (Zn) were examined. The results showed that the contents of serum TP and ALB and hepatic Fe and Zn decreased and the contents of serum TBI and DBI and hepatic Al and Cu increased in the chickens with AlCl3 This indicates that chronic administration of AlCl3 impairs the hepatic metabolism function and disorders the hepatic trace elements' distribution. © The Author(s) 2015.

  11. Neonatal bilirubin levels and childhood asthma in the US Collaborative Perinatal Project, 1959-1965.

    PubMed

    Huang, Lisu; Bao, Yixiao; Xu, Zongli; Lei, Xiaoping; Chen, Yan; Zhang, Yongjun; Zhang, Jun

    2013-12-15

    Evidence shows that asthma originates in early life. Studies have found that phototherapy and/or neonatal jaundice may be associated with asthma. We investigated the association between neonatal bilirubin levels and childhood asthma without phototherapy intervention in the Collaborative Perinatal Project, a multicenter prospective cohort study conducted in the United States from 1959 to 1965. A total of 54,795 livebirths were included, and 40,063 children were followed up until 7 years of age or older. Total serum bilirubin (TSB) levels were examined at 48 hours postpartum in newborns with birthweights of 2,250 g or more. Information on asthma and other diseases through age 7 years was summarized and confirmed by a group of pediatricians and child neurologists. Among 28,807 term infants, the overall prevalence of asthma was 5.26%. Risks of asthma increased with both maximum TSB levels and TSB levels at 48 hours postpartum (P for trend < 0.01). Neonatal maximum TSB levels greater than 15 mg/dL were associated with a 61% increase in the risk of childhood asthma (odds ratio = 1.61, 95% confidence interval: 1.04, 2.08) after adjustment for confounders. In this prospective cohort study of infants born at a time when phototherapy was unavailable, neonatal hyperbilirubinemia was associated with an increased risk of childhood asthma.

  12. CYP3A5*3 and bilirubin predict midazolam population pharmacokinetics in Asian cancer patients.

    PubMed

    Seng, Kok-Yong; Hee, Kim-Hor; Soon, Gaik Hong; Sapari, Nur Sabrina; Soong, Richie; Goh, Boon-Cher; Lee, Lawrence Soon-U

    2014-02-01

    We aim to evaluate the influence of covariates, including cytochrome P450 3A (CYP3A) genetic polymorphisms, on the pharmacokinetics of midazolam (MDZ) in Asian cancer patients, using a population pharmacokinetic approach. Pharmacokinetic data were obtained from 24 adult cancer patients who received an intravenous bolus dose of 1 mg MDZ as a CYP3A phenotyping probe, 1-day before starting FOLFIRI chemotherapy. Concentrations of MDZ and its major metabolites, 1'-hydroxymidazolam (1OHM) and 1'-hydroxymidazolam glucuronide (HMG) were measured using liquid chromatography/mass spectrometry. The population pharmacokinetic study was conducted using NONMEM. Demographics, clinical characteristics, and genetic polymorphisms were screened as covariates. A two-compartment model for MDZ and two sequential compartments representing 1OHM and HMG best described the data. The CYP3A5*3 and total bilirubin level significantly influenced MDZ clearance. The population typical MDZ clearance for CYP3A5*3 expressers was 22% lower than non-expressers. Baseline bodyweight was a statistically significant covariate for clearance and distribution volume of 1OHM. Creatinine clearance was positively correlated with HMG clearance. Our data indicate that CYP3A5*3, total bilirubin, bodyweight, and creatinine clearance are important predictors of MDZ and metabolite pharmacokinetics. Further studies in more patients are needed to explore the links between the identified covariates and the disposition of MDZ and its metabolites.

  13. Method for Estimating Bilirubin Isomerization Efficiency in Phototherapy to Treat Neonatal Jaundice

    NASA Astrophysics Data System (ADS)

    Lisenko, S. A.; Kugeiko, M. M.

    2014-11-01

    We propose a method for quantitative assessment of the efficacy of phototherapy to treat neonatal jaundice using the diffuse reflectance spectrum for the newborn's skin, based on the analytical dependence of the measured spectrum on the structural and morphological parameters of the skin, affecting the optical conditions in the medium, and an algorithm for rapid calculation of the bilirubin photoisomerization rate in the skin tissues as a function of the structural and morphological parameters of the skin and the wavelength of the exciting radiation. From the results of a numerical simulation of the process of radiation transport in the skin, we assess the stability of our method to variations in the scattering properties of the skin and the concentrations of its optically active chromophores (melanin, oxyhemoglobin, deoxyhemoglobin). We show that in order to achieve the maximum efficacy of phototherapy, we should use light from the range 484-496 nm. In this case, the intensity of the exciting radiation should be selected individually for each newborn according to the bilirubin photoisomerization rate characteristic for it.

  14. Profile of minocycline neuroprotection in bilirubin-induced auditory system dysfunction.

    PubMed

    Rice, Ann C; Chiou, Victoria L; Zuckoff, Sarah B; Shapiro, Steven M

    2011-01-12

    Excessive hyperbilirubinemia in human neonates can cause permanent dysfunction of the auditory system, as assessed with brainstem auditory evoked potentials (BAEPs). Jaundiced Gunn rat pups (jjs) exhibit similar BAEP abnormalities as hyperbilirubinemic neonates. Sulfadimethoxine (sulfa) administration to jjs, which displaces bilirubin from serum albumin into tissues including brain, exacerbates acute toxicity. Minocycline administered prior to sulfa in jjs protects against BAEP abnormalities. This study evaluates the neuroprotective capabilities of minocycline HCl (50 mg/kg) administered 30 or 120 min after sulfa (200 mg/kg) in 16 days old jjs. BAEPs are recorded at 6 or 24 h post-sulfa. Abnormal BAEP waves exhibit increased latency and decreased amplitude. The sulfa/saline treated jjs exhibited a significantly increased interwave interval between waves I and II (I-II IWI) and significantly decreased amplitudes of waves II and III compared to the saline/saline jjs. The minocycline 30 min post-sulfa (sulfa/mino+30) group was not significantly different from the saline/saline control group, indicating neuroprotection. The minocycline 120 min post-sulfa (sulfa/mino+120) group had a significantly decreased amplitude of wave III at both 6 and 24h. These studies indicate that minocycline has a graded neuroprotective effect when administered after acute bilirubin neurotoxicity.

  15. Amplifying the fluorescence of bilirubin enables the real-time detection of heme oxygenase activity.

    PubMed

    Klemz, Roman; Mashreghi, Mir-Farzin; Spies, Claudia; Volk, Hans-Dieter; Kotsch, Katja

    2009-01-15

    Heme oxygenases (HO) are the rate-limiting enzymes in the degradation of heme to equimolar amounts of antioxidant bile pigments, the signaling molecule carbon monoxide, and ferric iron. The inducible form HO-1 confers protection on cells and tissues that mediates beneficial effects in many diseases. Consequently, measurement of the enzymatic activity is vital in the investigation of the regulatory role of HO. Here we report that the fluorescence characteristics of bilirubin in complex with serum albumin can be used for the real-time detection of HO activity in enzymatic kinetics measurements. We characterized the enzymatic activity of a truncated human HO-1 and measured the HO activity for various cell types and organs, in either the basal naive or the HO-1-induced state. The bilirubin-dependent increase in fluorescence over time monitored by this assay facilitates a very fast, sensitive, and reliable measurement of HO activity. Our approach offers the basis for a highly sensitive high-throughput screening, which provides, inter alia, the opportunity to discover new therapeutic HO-1-inducing agents.

  16. Effects of Calcium Ions on Thermodynamic Properties of Mixed Bilirubin/Cholesterol Monolayers

    NASA Astrophysics Data System (ADS)

    Wu, Qiong; Tang, Yu-feng; Li, Ye-min; Xie, An-jian; Shen, Yu-hua; Zhu, Jin-miao; Li, Chuan-hao

    2008-04-01

    The mixed monolayer behavior of bilirubin/cholesterol was studied through surface pressure-area (π-A) isotherms on aqueous solutions containing various concentrations of calcium ions. Based on the data of π-A isotherms, the mean area per molecule, collapse pressure, surface compressibility modulus, excess molecular areas, free energy of mixing, and excess free energy of mixing of the monolayers on different subphases were calculated. The results show an expansion in the structure of the mixed monolayer with Ca2+ in subphase, and non-ideal mixing of the components at the air/water interface is observed with positive deviation from the additivity rule in the excess molecular areas. The miscibility between the components is weakened with the increase of concentration of Ca2+ in subphase. The facts indicate the presence of coordination between Ca2+ and the two components. The mixed monolayer, in which the molar ratio of bilirubin to cholesterol is 3:2, is more stable from a thermodynamic point of view on pure water. But the stable 3:2 stoichiometry complex is destroyed with the increase of the concentration of Ca2+ in subphase. Otherwise, the mixed monolayers have more thermodynamic stability at lower surface pressure on Ca2+ subphase.

  17. Milk xanthine oxidase type D (dehydrogenase) and type O (oxidase). Purification, interconversion and some properties

    PubMed Central

    Battelli, Maria Giulia; Lorenzoni, E.; Stirpe, F.

    1973-01-01

    1. The xanthine oxidase of cow's milk, crude or purified, appears as an oxidase (type O), and can be converted almost completely into a NAD+-dependent dehydrogenase (type D) by treatment with dithioerythritol or dihydrolipoic acid, but only to a small extent by other thiols. 2. The D form of the enzyme is inhibited by NADH, which competes with NAD+. 3. The kinetic constants of the two forms of the enzyme are similar to those of the corresponding forms of rat liver xanthine oxidase. 4. Milk xanthine oxidase is converted into an irreversible O form by pretreatment with chymotrypsin, papain or subtilisin, but only partially with trypsin. 5. The enzyme as purified shows a major faster band and a minor slower band on gel electrophoresis. The slower band is greatly reinforced after xanthine oxidase is converted into the irreversible O form by chymotrypsin. ImagesFig. 5. PMID:4352904

  18. Why copper is preferred over iron for oxygen activation and reduction in haem-copper oxidases

    NASA Astrophysics Data System (ADS)

    Bhagi-Damodaran, Ambika; Michael, Matthew A.; Zhu, Qianhong; Reed, Julian; Sandoval, Braddock A.; Mirts, Evan N.; Chakraborty, Saumen; Moënne-Loccoz, Pierre; Zhang, Yong; Lu, Yi

    2017-03-01

    Haem-copper oxidase (HCO) catalyses the natural reduction of oxygen to water using a haem-copper centre. Despite decades of research on HCOs, the role of non-haem metal and the reason for nature's choice of copper over other metals such as iron remains unclear. Here, we use a biosynthetic model of HCO in myoglobin that selectively binds different non-haem metals to demonstrate 30-fold and 11-fold enhancements in the oxidase activity of Cu- and Fe-bound HCO mimics, respectively, as compared with Zn-bound mimics. Detailed electrochemical, kinetic and vibrational spectroscopic studies, in tandem with theoretical density functional theory calculations, demonstrate that the non-haem metal not only donates electrons to oxygen but also activates it for efficient O-O bond cleavage. Furthermore, the higher redox potential of copper and the enhanced weakening of the O-O bond from the higher electron density in the d orbital of copper are central to its higher oxidase activity over iron. This work resolves a long-standing question in bioenergetics, and renders a chemical-biological basis for the design of future oxygen-reduction catalysts.

  19. Why copper is preferred over iron for oxygen activation and reduction in haem-copper oxidases

    NASA Astrophysics Data System (ADS)

    Bhagi-Damodaran, Ambika; Michael, Matthew A.; Zhu, Qianhong; Reed, Julian; Sandoval, Braddock A.; Mirts, Evan N.; Chakraborty, Saumen; Moënne-Loccoz, Pierre; Zhang, Yong; Lu, Yi

    2016-11-01

    Haem-copper oxidase (HCO) catalyses the natural reduction of oxygen to water using a haem-copper centre. Despite decades of research on HCOs, the role of non-haem metal and the reason for nature's choice of copper over other metals such as iron remains unclear. Here, we use a biosynthetic model of HCO in myoglobin that selectively binds different non-haem metals to demonstrate 30-fold and 11-fold enhancements in the oxidase activity of Cu- and Fe-bound HCO mimics, respectively, as compared with Zn-bound mimics. Detailed electrochemical, kinetic and vibrational spectroscopic studies, in tandem with theoretical density functional theory calculations, demonstrate that the non-haem metal not only donates electrons to oxygen but also activates it for efficient O-O bond cleavage. Furthermore, the higher redox potential of copper and the enhanced weakening of the O-O bond from the higher electron density in the d orbital of copper are central to its higher oxidase activity over iron. This work resolves a long-standing question in bioenergetics, and renders a chemical-biological basis for the design of future oxygen-reduction catalysts.

  20. Why copper is preferred over iron for oxygen activation and reduction in haem-copper oxidases.

    PubMed

    Bhagi-Damodaran, Ambika; Michael, Matthew A; Zhu, Qianhong; Reed, Julian; Sandoval, Braddock A; Mirts, Evan N; Chakraborty, Saumen; Moënne-Loccoz, Pierre; Zhang, Yong; Lu, Yi

    2017-03-01

    Haem-copper oxidase (HCO) catalyses the natural reduction of oxygen to water using a haem-copper centre. Despite decades of research on HCOs, the role of non-haem metal and the reason for nature's choice of copper over other metals such as iron remains unclear. Here, we use a biosynthetic model of HCO in myoglobin that selectively binds different non-haem metals to demonstrate 30-fold and 11-fold enhancements in the oxidase activity of Cu- and Fe-bound HCO mimics, respectively, as compared with Zn-bound mimics. Detailed electrochemical, kinetic and vibrational spectroscopic studies, in tandem with theoretical density functional theory calculations, demonstrate that the non-haem metal not only donates electrons to oxygen but also activates it for efficient O-O bond cleavage. Furthermore, the higher redox potential of copper and the enhanced weakening of the O-O bond from the higher electron density in the d orbital of copper are central to its higher oxidase activity over iron. This work resolves a long-standing question in bioenergetics, and renders a chemical-biological basis for the design of future oxygen-reduction catalysts.

  1. Petawatt laser absorption bounded

    PubMed Central

    Levy, Matthew C.; Wilks, Scott C.; Tabak, Max; Libby, Stephen B.; Baring, Matthew G.

    2014-01-01

    The interaction of petawatt (1015 W) lasers with solid matter forms the basis for advanced scientific applications such as table-top particle accelerators, ultrafast imaging systems and laser fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light f, and even the range of f is unknown. Here using a relativistic Rankine-Hugoniot-like analysis, we show for the first time that f exhibits a theoretical maximum and minimum. These bounds constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials. PMID:24938656

  2. Derivatives of 1-naphthyl ethylenediamine dihydrochloride for standardization of direct-bilirubin assays done with the Technicon "SMAC".

    PubMed

    Furda, J; Morgenstern, S; Snyder, L R

    1976-07-01

    The Jendrassik--Groff assay for direct bilirubin was adapted for analysis rates of 150/h on the Technicon "SMAC" continuous-flow analyzer. This requires development of a standard that is compatible with the other 19 channels on this analyzer. N-1-Naphthyl ethylenediamine dihydrochloride has been used for standardization of direct bilirubin assays, but we found it to be unsuitable because values for potassium are falsely elevated when potassium is determined with a valinomycin ion-selective electrode. This interference can be eliminated by alkylating the aliphatic amine group in the standard. The resulting compounds undergo the coupling reaction in the same way as the original compound and function equally well as standards for the direct bilirubin reaction. The only limitation of these analogs is their decreased solubility at physiological pH in some cases. Thus only certain alkyl groups are suitable.

  3. Birth weight, length, head circumference and bilirubin level in Indian newborns in the Sioux Lookout Zone, northwestern Ontario.

    PubMed

    Munroe, M; Shah, C P; Badgley, R; Bain, H W

    1984-09-01

    The norms for birth weight, length, head circumference and bilirubin level for native newborns have not been available. To develop appropriate norms, data were obtained from the charts on all live births in the Sioux Lookout Zone, northwestern Ontario, in 1968-69 and 1974-77. These data were correlated to maternal age and parity as well as sex of the infant. Despite impoverished living conditions, the birth weights of the study population were significantly higher than the Canadian norms; length and head circumference, however, were not significantly different. Over one third of the infants had serum bilirubin levels greater than 12 mg/dL (205 mumol/L). Increased maternal age was associated with increased birth weight and length and a lower bilirubin level.

  4. Evaluation of bilirubin concentration in hemolysed samples, is it really impossible? The altitude-curve cartography approach to interfered assays.

    PubMed

    Brunori, Paola; Masi, Piergiorgio; Faggiani, Luigi; Villani, Luciano; Tronchin, Michele; Galli, Claudio; Laube, Clarissa; Leoni, Antonella; Demi, Maila; La Gioia, Antonio

    2011-04-11

    Neonatal jaundice might lead to severe clinical consequences. Measurement of bilirubin in samples is interfered by hemolysis. Over a method-depending cut-off value of measured hemolysis, bilirubin value is not accepted and a new sample is required for evaluation although this is not always possible, especially with newborns and cachectic oncological patients. When usage of different methods, less prone to interferences, is not feasible an alternative recovery method for analytical significance of rejected data might help clinicians to take appropriate decisions. We studied the effects of hemolysis over total bilirubin measurement, comparing hemolysis-interfered bilirubin measurement with the non-interfered value. Interference curves were extrapolated over a wide range of bilirubin (0-30 mg/mL) and hemolysis (H Index 0-1100). Interference "altitude" curves were calculated and plotted. A bimodal acceptance table was calculated. Non-interfered bilirubin of given samples was calculated, by linear interpolation between the nearest lower and upper interference curves. Rejection of interference-sensitive data from hemolysed samples for every method should be based not upon the interferent concentration but upon a more complex algorithm based upon the concentration-dependent bimodal interaction between the interfered analyte and the measured interferent. The altitude-curve cartography approach to interfered assays may help laboratories to build up their own method-dependent algorithm and to improve the trueness of their data by choosing a cut-off value different from the one (-10% interference) proposed by manufacturers. When re-sampling or an alternative method is not available the altitude-curve cartography approach might also represent an alternative recovery method for analytical significance of rejected data. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Evaluation of the diagnostic value of serum level of total bilirubin in patients with suspected acute appendicitis.

    PubMed

    Motie, Mohammad Reza; Nik, Minoosadat Mousavi; Gharaee, Malihe

    2017-04-01

    Clinical diagnosis of acute appendicitis still remains a problem. Delays in diagnosis of acute appendicitis may cause perforation and septic peritonitis which result in increasing morbidity and mortality. The aim of this study was to determine the sensitivity, specificity and the diagnostic value of total serum bilirubin levels as a predictor of acute appendicitis. In this cross-sectional study, patients who underwent appendectomy with the diagnosis of acute appendicitis from April 2012 to March 2013 at Emam Reza Hospital in Mashhad (Iran) were enrolled. Serum bilirubin-Total and Direct-, were measured. Then based on the final pathologic reports, patients were categorized into five groups of normal appendix, chronic inflammatory changes, acute appendicitis, gangrenous and/or necrotic changes, and perforated appendicitis. Independent sample t-test, ANOVA, and Chi-square test were used for data analysis by SPSS version 16. There were 174 patients studied, (117 male, 57 female) with a mean age of 27.15±0.7 years. All of the patients had rebound tenderness; 75.3% had nausea, 58.6% had anorexia and 21.3% had fever. The histological reports of all patients showed 76.4% acute appendicitis. Analyzing p-values for SGPT, SGOT, WBC was (p=0.903) and differential count was (p=0.959). The study showed no significant difference between the pathological groups. However, there were no significant differences in serum total bilirubin levels between the pathological groups. Total bilirubin showed sensitivity of 48% and specificity of 61% in the diagnosis of acute appendicitis. Total serum bilirubin more than 0.85 mg/dl was the cut-off value with the best performance for diagnosis of appendicitis. Bilirubin levels are reliable, sensitive and specific to diagnosis and a prediction of complicated appendicitis.

  6. Evaluation of the diagnostic value of serum level of total bilirubin in patients with suspected acute appendicitis

    PubMed Central

    Motie, Mohammad Reza; Nik, Minoosadat Mousavi; Gharaee, Malihe

    2017-01-01

    Introduction Clinical diagnosis of acute appendicitis still remains a problem. Delays in diagnosis of acute appendicitis may cause perforation and septic peritonitis which result in increasing morbidity and mortality. The aim of this study was to determine the sensitivity, specificity and the diagnostic value of total serum bilirubin levels as a predictor of acute appendicitis. Methods In this cross-sectional study, patients who underwent appendectomy with the diagnosis of acute appendicitis from April 2012 to March 2013 at Emam Reza Hospital in Mashhad (Iran) were enrolled. Serum bilirubin-Total and Direct-, were measured. Then based on the final pathologic reports, patients were categorized into five groups of normal appendix, chronic inflammatory changes, acute appendicitis, gangrenous and/or necrotic changes, and perforated appendicitis. Independent sample t-test, ANOVA, and Chi-square test were used for data analysis by SPSS version 16. Results There were 174 patients studied, (117 male, 57 female) with a mean age of 27.15±0.7 years. All of the patients had rebound tenderness; 75.3% had nausea, 58.6% had anorexia and 21.3% had fever. The histological reports of all patients showed 76.4% acute appendicitis. Analyzing p-values for SGPT, SGOT, WBC was (p=0.903) and differential count was (p=0.959). The study showed no significant difference between the pathological groups. However, there were no significant differences in serum total bilirubin levels between the pathological groups. Total bilirubin showed sensitivity of 48% and specificity of 61% in the diagnosis of acute appendicitis. Total serum bilirubin more than 0.85 mg/dl was the cut-off value with the best performance for diagnosis of appendicitis. Conclusion Bilirubin levels are reliable, sensitive and specific to diagnosis and a prediction of complicated appendicitis. PMID:28607634

  7. The role of gamma-aminobutyric acid/glycinergic synaptic transmission in mediating bilirubin-induced hyperexcitation in developing auditory neurons.

    PubMed

    Yin, Xin-Lu; Liang, Min; Shi, Hai-Bo; Wang, Lu-Yang; Li, Chun-Yan; Yin, Shan-Kai

    2016-01-05

    Hyperbilirubinemia is a common clinical phenomenon observed in human newborns. A high level of bilirubin can result in severe jaundice and bilirubin encephalopathy. However, the cellular mechanisms underlying bilirubin excitotoxicity are unclear. Our previous studies showed the action of gamma-aminobutyric acid (GABA)/glycine switches from excitatory to inhibitory during development in the ventral cochlear nucleus (VCN), one of the most sensitive auditory nuclei to bilirubin toxicity. In the present study, we investigated the roles of GABAA/glycine receptors in the induction of bilirubin hyperexcitation in early developing neurons. Using the patch clamp technique, GABAA/glycine receptor-mediated spontaneous inhibitory synaptic currents (sIPSCs) were recorded from bushy and stellate cells in acute brainstem slices from young mice (postnatal day 2-6). Bilirubin significantly increased the frequency of sIPSCs, and this effect was prevented by pretreatments of slices with either fast or slow Ca(2+) chelators BAPTA-AM and EGTA-AM suggesting that bilirubin can increase the release of GABA/glycine via Ca(2+)-dependent mechanisms. Using cell-attached recording configuration, we found that antagonists of GABAA and glycine receptors strongly attenuated spontaneous spiking firings in P2-6 neurons but produced opposite effect in P15-19 neurons. Furthermore, these antagonists reversed bilirubin-evoked hyperexcitability in P2-6 neurons, indicating that excitatory action of GABA/glycinergic transmission specifically contribute to bilirubin-induced hyperexcitability in the early stage of development. Our results suggest that bilirubin-induced enhancement of presynaptic release GABA/Glycine via Ca(2+)-dependent mechanisms may play a critical role in mediating neuronal hyperexcitation associated with jaundice, implicating potential new strategies for predicting, preventing, and treating bilirubin neurotoxicity.

  8. Flavin-dependent alcohol oxidase from the yeast Pichia pinus. Spatial localization of the coenzyme FAD in the protein structure: hot-tritium bombardment and ESR experiments.

    PubMed Central

    Averbakh, A Z; Pekel, N D; Seredenko, V I; Kulikov, A V; Gvozdev, R I; Rudakova, I P

    1995-01-01

    The spatial localization of the coenzyme FAD in the quaternary structure of the alcohol oxidase from the yeast Pichia pinus was studied by tritium planigraphy and ESR methods. In the present paper we measured the specific radioactivity of FAD labelled as a part of the alcohol oxidase complex. The specific-radioactivity ratio for two FAD portions (FMN and AMP) was calculated. ESR experiments show 4 A (0.4 nm) to be the depth of immersion of paramagnetic isoalloxazines into alcohol oxidase octamer molecules. It is suggested that FAD molecules are bound to the surface of the octamer, rather than to the subunit interfaces. The orientation of the prosthetic group FAD in the alcohol oxidase protein is discussed. PMID:7654201

  9. The ccoNOQP gene cluster codes for a cb-type cytochrome oxidase that functions in aerobic respiration of Rhodobacter capsulatus.

    PubMed

    Thöny-Meyer, L; Beck, C; Preisig, O; Hennecke, H

    1994-11-01

    The genes for a new type of a haem-copper cytochrome oxidase were cloned from Rhodobacter capsulatus strain 37b4, using the Bradyrhizobium japonicum fixNOQP gene region as a hybridizing probe. Four genes, probably organized in an operon (ccoNOQP), were identified; their products share extensive amino acid sequence similarity with the FixN, O, Q and P proteins that have recently been shown to be the subunits of a cb-type oxidase. CcoN is a b-type cytochrome, CcoO and CcoP are membrane-bound mono- and dihaem c-type cytochromes and CcoQ is a small membrane protein of unknown function. Genes for a similar oxidase are also present in other non-rhizobial bacterial species such as Azotobacter vinelandii, Agrobacterium tumefaciens and Pseudomonas aeruginosa, as revealed by polymerase chain reaction analysis. A ccoN mutant was constructed whose phenotype, in combination with the structural information on the gene products, provides evidence that the CcoNOQP oxidase is a cytochrome c oxidase of the cb type, which supports aerobic respiration in R. capsulatus and which is probably identical to the cbb3-type oxidase that was recently purified from a different strain of the same species. Mutant analysis also showed that this oxidase has no influence on photosynthetic growth and nitrogen-fixation activity.

  10. Universal bounds on current fluctuations

    NASA Astrophysics Data System (ADS)

    Pietzonka, Patrick; Barato, Andre C.; Seifert, Udo

    2016-05-01

    For current fluctuations in nonequilibrium steady states of Markovian processes, we derive four different universal bounds valid beyond the Gaussian regime. Different variants of these bounds apply to either the entropy change or any individual current, e.g., the rate of substrate consumption in a chemical reaction or the electron current in an electronic device. The bounds vary with respect to their degree of universality and tightness. A universal parabolic bound on the generating function of an arbitrary current depends solely on the average entropy production. A second, stronger bound requires knowledge both of the thermodynamic forces that drive the system and of the topology of the network of states. These two bounds are conjectures based on extensive numerics. An exponential bound that depends only on the average entropy production and the average number of transitions per time is rigorously proved. This bound has no obvious relation to the parabolic bound but it is typically tighter further away from equilibrium. An asymptotic bound that depends on the specific transition rates and becomes tight for large fluctuations is also derived. This bound allows for the prediction of the asymptotic growth of the generating function. Even though our results are restricted to networks with a finite number of states, we show that the parabolic bound is also valid for three paradigmatic examples of driven diffusive systems for which the generating function can be calculated using the additivity principle. Our bounds provide a general class of constraints for nonequilibrium systems.

  11. Distortion of Flavin Geometry Is Linked to Ligand Binding in Cholesterol Oxidase

    SciTech Connect

    Lyubimov, A.Y.; Heard, K.; Tang, H.; Sampson, N.S.; Vrielink, A.

    2009-06-03

    Two high-resolution structures of a double mutant of bacterial cholesterol oxidase in the presence or absence of a ligand, glycerol, are presented, showing the trajectory of glycerol as it binds in a Michaelis complex-like position in the active site. A group of three aromatic residues forces the oxidized isoalloxazine moiety to bend along the N5-N10 axis as a response to the binding of glycerol in the active site. Movement of these aromatic residues is only observed in the glycerol-bound structure, indicating that some tuning of the FAD redox potential is caused by the formation of the Michaelis complex during regular catalysis. This structural study suggests a possible mechanism of substrate-assisted flavin activation, improves our understanding of the interplay between the enzyme, its flavin cofactor and its substrate, and is of use to the future design of effective cholesterol oxidase inhibitors.

  12. Cytochrome c oxidase from Paracoccus denitrificans in Triton X-100: aggregation state and kinetics.

    PubMed

    Bolli, R; Nałecz, K A; Azzi, A

    1986-08-01

    Cytochrome c oxidase from Paracoccus denitrificans was homogeneously dispersed in Triton X-100. Using gel exclusion chromatography and sucrose gradient centrifugation analysis a molecular weight of the detergent-protein complex of 155,000 was determined. After subtraction of the bound detergent (111 mol/mol heme aa3) a molecular weight of 85,000 resulted, which agreed well with the model of a monomer containing two subunits. This monomer showed high cytochrome c oxidase activity when measured spectrophotometrically in the presence of Triton X-100 (Vmax = 85 s-1). The molecular activity, plotted according to Eadie-Hofstee, was monophasic as a function of the cytochrome c concentration. A Km of 3.6 X 10(-6) M was evaluated, similar to the Km observed in the presence of dodecyl maltoside [Nałecz et al. (1985).

  13. Distortion of flavin geometry is linked to ligand binding in cholesterol oxidase

    PubMed Central

    Lyubimov, Artem Y.; Heard, Kathryn; Tang, Hui; Sampson, Nicole S.; Vrielink, Alice

    2007-01-01

    Two high-resolution structures of a double mutant of bacterial cholesterol oxidase in the presence or absence of a ligand, glycerol, are presented, showing the trajectory of glycerol as it binds in a Michaelis complex-like position in the active site. A group of three aromatic residues forces the oxidized isoalloxazine moiety to bend along the N5-N10 axis as a response to the binding of glycerol in the active site. Movement of these aromatic residues is only observed in the glycerol-bound structure, indicating that some tuning of the FAD redox potential is caused by the formation of the Michaelis complex during regular catalysis. This structural study suggests a possible mechanism of substrate-assisted flavin activation, improves our understanding of the interplay between the enzyme, its flavin cofactor and its substrate, and is of use to the future design of effective cholesterol oxidase inhibitors. PMID:18029419

  14. Cyanide inhibition of cytochrome c oxidase. A rapid-freeze e.p.r. investigation.

    PubMed Central

    Jensen, P; Wilson, M T; Aasa, R; Malmström, B G

    1984-01-01

    The inhibition of cytochrome c oxidase by cyanide, starting either with the resting or the pulsed enzyme, was studied by rapid-freeze quenching followed by quantitative e.p.r. It is found that a partial reduction of cytochrome oxidase by transfer of 2 electron equivalents from ferrocytochrome c to cytochrome a and CuA will induce a transition from a closed to an open enzyme conformation, rendering the cytochrome a3-CuB site accessible for cyanide binding, possibly as a bridging ligand. A heterogeneity in the enzyme is observed in that an e.p.r. signal from the cytochrome a3 3+-HCN complex is only found in 20% of the molecules, whereas the remaining cyanide-bound a3-CuB sites are e.p.r.-silent. PMID:6098268

  15. Crystallization of a truncated soluble human semicarbazide-sensitive amine oxidase

    PubMed Central

    Jakobsson, Emma; Nilsson, Joakim; Källström, Ulla; Ogg, Derek; Kleywegt, Gerard J.

    2005-01-01

    Human semicarbazide-sensitive amine oxidase (SSAO) is a homodimeric copper-containing monoamine oxidase that occurs in both a membrane-bound and a soluble form. SSAO is also known as vascular adhesion protein-1 (VAP-1). A truncated soluble form of human SSAO (comprising residues 29–763) was expressed in human embryonic kidney 293 cells and purified to homogeneity. Tetragonal crystals were obtained and a data set extending to 2.5 Å was collected. The crystals are merohedrally twinned and the estimation of the twinning fraction was complicated by pseudo-symmetry and the anisotropic character of the crystals. Using a recently developed method for twinning detection that is insensitive to phenomena such as anisotropy or pseudo-symmetry [Padilla & Yeates (2003 ▶), Acta Cryst. D59, 1124–1130], the twinning fraction was estimated to be 0.3. The structure was eventually solved by molecular replacement in space group P43. PMID:16511016

  16. Indoleacetic Acid Oxidase: A Dual Catalytic Enzyme?

    PubMed Central

    Hoyle, M. C.

    1972-01-01

    The isolation of a unique enzyme capable of oxidizing indoleacetic acid, but devoid of peroxidase activity, has been reported for preparations from tobacco roots and commercial horseradish peroxidase. Experiments were made to verify these results using enzyme obtained from Betula leaves and commercial horseradish peroxidase. Both indoleacetic acid oxidase and guaiacol peroxidase activity appeared at 2.5 elution volumes from sulfoethyl-Sephadex. These results were obtained with both sources of enzyme. In no case was a separate peak of indoleacetic acid oxidase activity obtained at 5.4 elution volumes as reported for the tobacco enzyme using the same chromatographic system. Both types of activity, from both sources of enzyme, also eluted together during gel filtration. Successful column chromatography of Betula enzyme was dependent upon previous purification by membrane ultrafiltration. These results indicate indoleacetic acid oxidase activity and guaiacol peroxidase activity are dual catalytic functions of a single enzyme. PMID:16658111

  17. Effect of naphthalene on cytochrome oxidase activity

    SciTech Connect

    Harmon, H.J.

    1988-01-01

    Previous reports have demonstrated that naphthalene inhibits oxygen consumption in Daphnia magna tissue culture cells, and intact mitochondria and submitochondrial particles. These studies were extended to algal mitochondrial respiration as well as photosynthetic activity. The authors were able to demonstrate the specific site of apparent respiratory inhibition to be coenzyme Q (ubiquinone, UQ) and later to demonstrate the molecular basis of this inhibition at ubiquinone. The authors previously could not demonstrate an effect of naphthalene on cytochrome oxidase activity. However, the observation that naphthalene can stimulate respiration in algae prompted the reinvestigation of the effect of naphthalene on the kinetics of cytochrome oxidase. Cytochrome oxidase is a multi-subunit membranous protein responsible for the oxidation of cytochrome c and the reduction of molecular oxygen to water. Because of the complicated nature and mechanism of this enzyme, the potential exists for multiple and possibly opposite effects of naphthalene on its function.

  18. Biliary and urinary excretion rates and serum concentration changes of four bilirubin photoproducts in Gunn rats during total darkness and low or high illumination.

    PubMed Central

    Onishi, S; Ogino, T; Yokoyama, T; Isobe, K; Itoh, S; Yamakawa, T; Hashimoto, T

    1984-01-01

    On cycled exposure of Gunn rats to total darkness and low and high illumination, biliary excretion rates of (EZ)- and (ZE)-bilirubin and (EZ)-cyclobilirubin increased up to approx. 10-fold from the mean basal values of 1.2 and 0.2 microgram/h to the mean maximum values of 25.2 and 4.2 micrograms/h respectively, and at the same time those of (EE)-bilirubin and (EE)-cyclobilirubin also increased, but at very much lower rates than those of the first-mentioned two. During the low illumination only (EZ)- and (ZE)-bilirubin and (EZ)-cyclobilirubin appeared in the urine; during the high illumination (EE)-bilirubin and (EE)-cyclobilirubin also appeared, showing a similar excretion pattern to that observed in the bile, but the total urinary excretion rates were lower than the total biliary excretion rates. The serum bilirubin concentrations fell gradually to lower values, accompanied by an increment in (EZ)- and (ZE)-bilirubin, but (EZ)-cyclobilirubin was not detected. It is concluded that during phototherapy the predominant pathway for the removal of bilirubin from the body in the Gunn rat is by biliary excretion of the geometric photoisomers (EZ)- and (ZE)-bilirubin, derived from Z----E isomerization, and the structural photoisomer (EZ)-cyclobilirubin, formed from intramolecular endo-vinyl cyclization. PMID:6477496

  19. Accurate and sensitive high-performance liquid chromatographic method for geometrical and structural photoisomers of bilirubin IX alpha using the relative molar absorptivity values.

    PubMed

    Itoh, S; Isobe, K; Onishi, S

    1999-07-02

    It has been reported that considerable differences exist between the relative molar absorptivity values of the geometrical and structural photoisomers of bilirubin. We have devised an accurate HPLC method for photoisomer quantification based on the following principle: the sum of both the integrated peak areas corrected by each factor for each photoisomer, and the integrated peak area of unchanged (ZZ)-bilirubin [(ZZ)-B] after an anaerobic photoirradiation, should be constant and equal to the integrated peak area of initial (ZZ)-bilirubin [(ZZ)-Bi] before photoirradiation. On this basis, the following equation can be used to determine each factor. [equation: see text] alpha, beta, gamma and delta represent the factors used to correct the integrated peak areas of individual bilirubin photoisomers, and they are arranged in the order of the formula. It was demonstrated that the relative 455 nm molar absorptivity values for (ZZ)-bilirubin and all its geometrical and structural photoisomers, i.e., (ZZ)-bilirubin, (ZE)-bilirubin (EZ)-bilirubin, (EZ)-cyclobilirubin (= lumirubin) and (EE)-cyclobilirubin in the HPLC eluent, are, respectively, 1.0, 0.81 (= alpha), 0.54 (= beta), 0.47 (= gamma) and 0.39 (= delta).

  20. Starchy biomass-powered enzymatic biofuel cell based on amylases and glucose oxidase multi-immobilized bioanode.

    PubMed

    Yamamoto, Kazuhiro; Matsumoto, Takuya; Shimada, Shota; Tanaka, Tsutomu; Kondo, Akihiko

    2013-06-25

    The present study reports the design of a novel bioanode to directly utilize starch as a fuel in an enzymatic biofuel cell. The enzymatic fuel cell is based on three enzymes (alpha-amylase, glucoamylase and glucose oxidase). The carbon paste electrode containing these three enzymes and tetrathiafulvalene can both saccharize and oxidize starchy biomass. In cyclic voltammetry, catalytic currents were successfully observed with both glucose and starchy white rice used as a substrate. Finally, a membrane-less white rice/O2 biofuel cell was assembled and the electrochemical performance was evaluated. The three enzyme based electrode was used as a bioanode and an immobilized bilirubin oxidase (derived from Myrothecium verrucaria) electrode was used as a biocathode. The biofuel cell delivered an open circuit voltage of 0.522V and power density of up to 99.0 μWcm(-2). Our results show that a readily available fuel can be used for enzymatic fuel cells, and will lead to new designs.

  1. Mediated electron transfer of cellobiose dehydrogenase and glucose oxidase at osmium polymer-modified nanoporous gold electrodes.

    PubMed

    Salaj-Kosla, Urszula; Scanlon, Micheál D; Baumeister, Tobias; Zahma, Kawah; Ludwig, Roland; Ó Conghaile, Peter; MacAodha, Domhnall; Leech, Dónal; Magner, Edmond

    2013-04-01

    Nanoporous and planar gold electrodes were utilised as supports for the redox enzymes Aspergillus niger glucose oxidase (GOx) and Corynascus thermophilus cellobiose dehydrogenase (CtCDH). Electrodes modified with hydrogels containing enzyme, Os-redox polymers and the cross-linking agent poly(ethylene glycol)diglycidyl ether were used as biosensors for the determination of glucose and lactose. Limits of detection of 6.0 (±0.4), 16.0 (±0.1) and 2.0 (±0.1) μM were obtained for CtCDH-modified lactose and glucose biosensors and GOx-modified glucose biosensors, respectively, at nanoporous gold electrodes. Biofuel cells composed of GOx- and CtCDH-modified gold electrodes were utilised as anodes, together with Myrothecium verrucaria bilirubin oxidase (MvBOD) or Melanocarpus albomyces laccase as cathodes, in biofuel cells. A maximum power density of 41 μW/cm(2) was obtained for a CtCDH/MvBOD biofuel cell in 5 mM lactose and O2-saturated buffer (pH 7.4, 0.1 M phosphate, 150 mM NaCl).

  2. Molecular Dynamic Studies of the Complex Polyethylenimine and Glucose Oxidase

    PubMed Central

    Szefler, Beata; Diudea, Mircea V.; Putz, Mihai V.; Grudzinski, Ireneusz P.

    2016-01-01

    Glucose oxidase (GOx) is an enzyme produced by Aspergillus, Penicillium and other fungi species. It catalyzes the oxidation of β-d-glucose (by the molecular oxygen or other molecules, like quinones, in a higher oxidation state) to form d-glucono-1,5-lactone, which hydrolyses spontaneously to produce gluconic acid. A coproduct of this enzymatic reaction is hydrogen peroxide (H2O2). GOx has found several commercial applications in chemical and pharmaceutical industries including novel biosensors that use the immobilized enzyme on different nanomaterials and/or polymers such as polyethylenimine (PEI). The problem of GOx immobilization on PEI is retaining the enzyme native activity despite its immobilization onto the polymer surface. Therefore, the molecular dynamic (MD) study of the PEI ligand (C14N8_07_B22) and the GOx enzyme (3QVR) was performed to examine the final complex PEI-GOx stabilization and the affinity of the PEI ligand to the docking sites of the GOx enzyme. The docking procedure showed two places/regions of major interaction of the protein with the polymer PEI: (LIG1) of −5.8 kcal/mol and (LIG2) of −4.5 kcal/mol located inside the enzyme and on its surface, respectively. The values of enthalpy for the PEI-enzyme complex, located inside of the protein (LIG1) and on its surface (LIG2) were computed. Docking also discovered domains of the GOx protein that exhibit no interactions with the ligand or have even repulsive characteristics. The structural data clearly indicate some differences in the ligand PEI behavior bound at the two places/regions of glucose oxidase. PMID:27801788

  3. Molecular Dynamic Studies of the Complex Polyethylenimine and Glucose Oxidase.

    PubMed

    Szefler, Beata; Diudea, Mircea V; Putz, Mihai V; Grudzinski, Ireneusz P

    2016-10-27

    Glucose oxidase (GOx) is an enzyme produced by Aspergillus, Penicillium and other fungi species. It catalyzes the oxidation of β-d-glucose (by the molecular oxygen or other molecules, like quinones, in a higher oxidation state) to form d-glucono-1,5-lactone, which hydrolyses spontaneously to produce gluconic acid. A coproduct of this enzymatic reaction is hydrogen peroxide (H₂O₂). GOx has found several commercial applications in chemical and pharmaceutical industries including novel biosensors that use the immobilized enzyme on different nanomaterials and/or polymers such as polyethylenimine (PEI). The problem of GOx immobilization on PEI is retaining the enzyme native activity despite its immobilization onto the polymer surface. Therefore, the molecular dynamic (MD) study of the PEI ligand (C14N8_07_B22) and the GOx enzyme (3QVR) was performed to examine the final complex PEI-GOx stabilization and the affinity of the PEI ligand to the docking sites of the GOx enzyme. The docking procedure showed two places/regions of major interaction of the protein with the polymer PEI: (LIG1) of -5.8 kcal/mol and (LIG2) of -4.5 kcal/mol located inside the enzyme and on its surface, respectively. The values of enthalpy for the PEI-enzyme complex, located inside of the protein (LIG1) and on its surface (LIG2) were computed. Docking also discovered domains of the GOx protein that exhibit no interactions with the ligand or have even repulsive characteristics. The structural data clearly indicate some differences in the ligand PEI behavior bound at the two places/regions of glucose oxidase.

  4. Coordination chemistry controls the thiol oxidase activity of the B12-trafficking protein CblC.

    PubMed

    Li, Zhu; Shanmuganathan, Aranganathan; Ruetz, Markus; Yamada, Kazuhiro; Lesniak, Nicholas A; Kräutler, Bernhard; Brunold, Thomas C; Koutmos, Markos; Banerjee, Ruma

    2017-06-09

    The cobalamin or B12 cofactor supports sulfur and one-carbon metabolism and the catabolism of odd-chain fatty acids, branched-chain amino acids, and cholesterol. CblC is a B12-processing enzyme involved in an early cytoplasmic step in the cofactor-trafficking pathway. It catalyzes the glutathione (GSH)-dependent dealkylation of alkylcobalamins and the reductive decyanation of cyanocobalamin. CblC from Caenorhabditis elegans (ceCblC) also exhibits a robust thiol oxidase activity, converting reduced GSH to oxidized GSSG with concomitant scrubbing of ambient dissolved O2 The mechanism of thiol oxidation catalyzed by ceCblC is not known. In this study, we demonstrate that novel coordination chemistry accessible to ceCblC-bound cobalamin supports its thiol oxidase activity via a glutathionyl-cobalamin intermediate. Deglutathionylation of glutathionyl-cobalamin by a second molecule of GSH yields GSSG. The crystal structure of ceCblC provides insights into how architectural differences at the α- and β-faces of cobalamin promote the thiol oxidase activity of ceCblC but mute it in wild-type human CblC. The R161G and R161Q mutations in human CblC unmask its latent thiol oxidase activity and are correlated with increased cellular oxidative stress disease. In summary, we have uncovered key architectural features in the cobalamin-binding pocket that support unusual cob(II)alamin coordination chemistry and enable the thiol oxidase activity of ceCblC. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  5. Multifunctions of bounded variation

    NASA Astrophysics Data System (ADS)

    Vinter, R. B.

    2016-02-01

    Consider control systems described by a differential equation with a control term or, more generally, by a differential inclusion with velocity set F (t , x). Certain properties of state trajectories can be derived when it is assumed that F (t , x) is merely measurable w.r.t. the time variable t. But sometimes a refined analysis requires the imposition of stronger hypotheses regarding the time dependence. Stronger forms of necessary conditions for minimizing state trajectories can be derived, for example, when F (t , x) is Lipschitz continuous w.r.t. time. It has recently become apparent that significant addition properties of state trajectories can still be derived, when the Lipschitz continuity hypothesis is replaced by the weaker requirement that F (t , x) has bounded variation w.r.t. time. This paper introduces a new concept of multifunctions F (t , x) that have bounded variation w.r.t. time near a given state trajectory, of special relevance to control. We provide an application to sensitivity analysis.

  6. Membrane-bound selenoproteins.

    PubMed

    Liu, Jun; Rozovsky, Sharon

    2015-10-01

    Selenoproteins employ selenium to supplement the chemistry available through the common 20 amino acids. These powerful enzymes are affiliated with redox biology, often in connection with the detection, management, and signaling of oxidative stress. Among them, membrane-bound selenoproteins play prominent roles in signaling pathways, Ca(2+) regulation, membrane complexes integrity, and biosynthesis of lipophilic molecules. The number of selenoproteins whose physiological roles, protein partners, expression, evolution, and biosynthesis are characterized is steadily increasing, thus offering a more nuanced view of this specialized family. This review focuses on human membrane selenoproteins, particularly the five least characterized ones: selenoproteins I, K, N, S, and T. Membrane-bound selenoproteins are the least understood, as it is challenging to provide the membrane-like environment required for their biochemical and biophysical characterization. Hence, their studies rely mostly on biological rather than structural and biochemical assays. Another aspect that has not received much attention is the particular role that their membrane association plays in their physiological function. Findings cited in this review show that it is possible to infer the structure and the membrane-binding mode of these lesser-studied selenoproteins and design experiments to examine the role of the rare amino acid selenocysteine.

  7. Role of bilirubin as antioxidant in neonatal jaundice and effect of ethanolic extract of sweet lime peel on experimentally induced jaundice in rat.

    PubMed

    Nag, N; Halder, S; Chaudhuri, R; Adhikary, S; Mazumder, S

    2009-02-01

    Bilirubin above a threshold level is toxic to human system and is excreted in urinary and through gastrointestinal tract. The role of bilirubin as antioxidant is debatable. This paper aims at elucidating the role of bilirubin as an antioxidant in neonatal jaundice patients. It is observed that bilirubin up to 6 mg/dl in blood acts as an antioxidant and above 12.5 mg/dl is strongly prooxidant. Phototherapy is the accepted therapeutic management of neonatal jaundice and has been shown to enhance the oxidative stress. Approaches have been taken to formulate a herbal medication which will reduce bilirubin level in the neonates without inducing additional damages. The ethanolic extract of sweet lime peel, administered orally at a dose of 72 microg is found to reduce the oxidative stress in erythrocytes of phenylhydrazine-induced jaundiced rats treated with phototherapy.

  8. Bilirubin, formed by activation of heme oxygenase-2, protects neurons against oxidative stress injury

    PubMed Central

    Doré, Sylvain; Takahashi, Masaaki; Ferris, Christopher D.; Hester, Lynda D.; Guastella, Daniel; Snyder, Solomon H.

    1999-01-01

    Heme oxygenase (HO) catalyzes the conversion of heme to carbon monoxide, iron, and biliverdin, which is immediately reduced to bilirubin (BR). Two HO active isozymes exist: HO1, an inducible heat shock protein, and HO2, which is constitutive and highly concentrated in neurons. We demonstrate a neuroprotective role for BR formed from HO2. Neurotoxicity elicited by hydrogen peroxide in hippocampal and cortical neuronal cultures is prevented by the phorbol ester, phorbol 12-myristate 13-acetate (PMA) via stimulation of protein kinase C. We observe phosphorylation of HO2 through the protein kinase C pathway with enhancement of HO2 catalytic activity and accumulation of BR in neuronal cultures. The neuroprotective effects of PMA are prevented by the HO inhibitor tin protoporphyrin IX and in cultures from mice with deletion of HO2 gene. Moreover, BR, an antioxidant, is neuroprotective at nanomolar concentrations. PMID:10051662

  9. The location of the high- and low-affinity bilirubin-binding sites on serum albumin: ligand-competition analysis investigated by circular dichroism.

    PubMed

    Goncharova, Iryna; Orlov, Sergey; Urbanová, Marie

    2013-01-01

    The locations of three bilirubin (BR)-binding sites with different affinities were identified as subdomains IB, IIA and IIIA for five mammalian serum albumins (SAs): human (HSA), bovine (BSA), rat, (RSA), rabbit (RbSA) and sheep (SSA). The stereoselectivity of a high-affinity BR-binding site was identified in the BR/SA=1/1 system by circular dichroism (CD) spectroscopy, the sites with low affinity to BR were analyzed using difference CD. Site-specific ligand-competition experiments with ibuprofen (marker for subdomain IIIA) and hemin (marker for subdomain IB) did not reveal any changes for the BR/SA=1/1 system and showed a decrease of the bound BR at BR/SA=3/1. Both sites were identified as sites with low affinity to BR. The correlation between stereoselectivity and the arrangement of Arg-Lys residues indicated similarity between the BR-binding sites in subdomain IIIA for all of the SAs studied. Subdomain IB in HSA, BSA, SSA and RbSA has P-stereoselectivity while in RSA it has M-selectivity toward BR. A ligand-competition experiment with gossypol shows a decrease of the CD signal of bound BR for the BR/SA=1/1 system as well as for BR/SA=3/1. Subdomain IIA was assigned as a high-affinity BR-binding site. The P-stereoselectivity of this site in HSA (and RSA, RbSA) was caused by the right-hand localization of charged residues R257/R218-R222, whereas the left-hand orientation of R257/R218-R199 led to the M-stereoselectivity of the primary binding site in BSA (and SSA).

  10. Total bilirubin level may be a biomarker of nephropathy in type 2 diabetes mellitus

    PubMed Central

    Zhang, Dan; Zhu, Bo; Zhang, Wei; Wang, Wei; Guo, Dan; Yang, Ligang; Wang, Lu

    2017-01-01

    Abstract Recently, the number of the studies on the relationship between the total bilirubin level (TBL) and diabetic nephropathy (DN) is increasing, but their results were not consistent. Therefore, we performed a meta-analysis to analyze the relationship between TBL and the risk of DN. We searched 5 databases before October 31, 2016, and reviewed the reference list of relevant articles. The fixed or random-effects model was used to pool risk estimates. We conducted the dose–response meta-analysis to evaluate the relationship between TBL and the risk of DN. Our meta-analysis showed that TBL in the DN group was lower than that in diabetes without the kidney disease (NDN) group (standard mean difference [SMD]: −0.63, 95% CI: −0.80, −0.46). The result of each subgroup also showed that TBL in the DN group was lower than that in the NDN group. The result of meta-regression indicated that duration of diabetes mellitus might be the source of heterogeneity. Our meta-analysis also showed that there was a significant negative relationship between TBL and the risk of DN (OR: 0.86, 95%CI: 0.82, 0.90). The results of subgroup analysis were similar to those of SMD; no sources of heterogeneity were detected by meta-regression. Sensitivity analysis indicated that the results were robust. We observed a linear association between TBL and the risk of DN, and there was a negative dose–response association between TBL and the risk of DN. In conclusion, bilirubin may be used as a biomarker of DN. It helps early diagnosis and effective therapeutic strategies on DN. PMID:28072721

  11. The effect of UGT1A1 promoter polymorphism on bilirubin response to hydroxyurea therapy in hemoglobinopathies.

    PubMed

    Italia, Khushnooma Y; Jijina, Farah F; Jain, Dipty; Merchant, Rashid; Nadkarni, Anita H; Mukherjee, Malay; Ghosh, Kanjaksha; Colah, Roshan B

    2010-11-01

    Hydroxyurea is known to reduce ineffective erythropoiesis and thereby hemolysis leading to a reduction in bilirubin levels in patients with hemoglobinopathies. However, the effect of hydroxyurea on hyperbilirubinemia in relation to the UGT1A1 gene promoter polymorphism is not known in Indian patients with different hemoglobinopathies. We studied 112 patients (77 sickle cell anemia, 22 β-thalassemia intermedia and 13 HbE-β-thalassemia) who were on hydroxyurea therapy for 2 years for their response towards hyperbilirubinemia associated with UGT1A1 promoter polymorphism. The patients with (TA)(7)/(TA)(7) repeats had significantly higher serum bilirubin levels than those with (TA)(6)/(TA)(6) repeats in all the groups and the reduction in serum bilirubin after hydroxyurea therapy was still higher among patients with (TA)(7)/(TA)(7) repeats when compared with (TA)(6)/(TA)(6) repeats. Higher bilirubin levels were associated with the (TA)(7)/(TA)(7) sequence however they did not come down to normal levels after hydroxyurea therapy. Copyright © 2010. Published by Elsevier Inc.

  12. Unbound free fatty acids from preterm infants treated with intralipid decouples unbound from total bilirubin potentially making phototherapy ineffective.

    PubMed

    Hegyi, Thomas; Kathiravan, Suganya; Stahl, Gary E; Huber, Andrew H; Kleinfeld, Alan

    2013-01-01

    Extremely low birth weight (ELBW; <1,000 g) infants have poor outcomes, often compromised by bilirubin neurotoxicity. We measured unbound bilirubin (Bf) and unbound free fatty acid (FFAu) levels in 5 ELBW infants in a trial examining the effects of pharmacologic ductal closure on infants treated with Intralipid infusion (3 g/kg/day). The levels for all infants (mean ± SD) were: total serum bilirubin (TSB) 4.6 ± 1.7 mg/dl, FFAu 376 ± 496 nM, and Bf 42 ± 30 nM. Of the 3 infants who died, 2 had TSB <5.9 mg/dl but FFAu >580 nM and Bf >75 nM. Multiple regression revealed a major effect on Bf levels due to FFAu, indicating that Intralipid elevated levels of FFAu and Bf. Indomethacin or ibuprofen reduced Bf levels, most likely by reducing FFAu levels through lipase inhibition. Because displacement of Bf by FFAu decouples Bf from TSB, phototherapy may not reduce the risk of bilirubin or FFAu toxicity in Intralipid-treated ELBW infants.

  13. Inhibition of Human UGT1A1-Mediated Bilirubin Glucuronidation by Polyphenolic Acids Impact Safety of Popular Salvianolic Acid A/B-Containing Drugs and Herbal Products.

    PubMed

    Ma, Guo; Zhang, Ying; Chen, Wenyan; Tang, Zhifang; Xin, Xiaoming; Yang, Ping; Liu, Xiaoqin; Cai, Weimin; Hu, Ming

    2017-09-05

    Bilirubin-related adverse reactions (ADR, e.g., jaundice and hyperbilirubinemia) induced by herbs rich in certain polyphenolic acids are widely reported. However, the causes and the mechanisms underlying these ADR are not well understood. The purpose of this article is to determine the mechanism by which certain polyphenolic acids inhibit UGT1A1-mediated bilirubin glucuronidation, leading to jaundice or hyperbilirubinemia. We investigated in vitro inhibitory effects on bilirubin glucuronidation of salvianolic acid A (SAA), salvianolic acid B (SAB), danshensu (DSS), protocatechuic aldehyde (PA), and rosmarinic acid (RA), as well as two Salvia miltiorrhiza injections (DSI and CDI) rich in polyphenolic acids. The results showed that average formation rates of three bilirubin glucuronides displayed a significant difference (p < 0.05) and the formation of monoglucuronide was favored regardless if an inhibitor was present or not. SAA, SAB, DSI, and CDI, but not DSS, PA, and RA, significantly inhibited human UGT1A1-mediated bilirubin glucuronidation via a mixed-type inhibitory mechanism. Average IC50 values of SAA, SAB, DSI, and CDI-mediated inhibition of bilirubin glucuronidation were bilirubin concentration-dependent, and their values (against total bilirubin glucuronidation) were in the range 0.44 ± 0.02 to 0.86 ± 0.04 μg/mL (for SAA), 4.22 ± 0.30 to 12.50 ± 0.93 μg/mL (for SAB), 9.29 ± 0.76 to 18.82 ± 0.63 μg/mL (for DSI), and 9.18 ± 2.00 to 22.36 ± 1.39 μg/mL (for CDI), respectively. In conclusion, SAA and its analog SAB are the main ingredients responsible for inhibition of bilirubin glucuronidation by DSI and CDI, whose use is associated with many high bilirubin-related ADR.

  14. 21 CFR 866.2420 - Oxidase screening test for gonorrhea.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Section 866.2420 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2420 Oxidase... ingredient that will react with cytochrome oxidase. When cytochrome oxidase is present, the swab turns a...

  15. 21 CFR 866.2420 - Oxidase screening test for gonorrhea.

    Code of Federal Regulation