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Sample records for biopterin

  1. Significance of biopterin induction in rats with postburn Staphylococcus aureus sepsis

    Institute of Scientific and Technical Information of China (English)

    Li Hongyun; Yao Yongming; Shi Zhiguo; Dong Ning; Yu Yan; Lu Lianrong; Sheng Zhiyong

    2002-01-01

    Objective: It has been demonstrated that biopterin, an essential cofactor of nitric oxide synthase (NOS), plays an important role in the pathogenesis of endotoxin-induced shock, yet its biological significance in gram-positive sepsis remains unclear. In this study, we adopted a rat model of postburn Staphylococcus aureus (S.aureus) sepsis to observe the time course and tissue distribution of biopterin in postburn S. aureus infection, and to investigate its potential role in the pathogenesis of gram-positive sepsis. Wistar rats were inflicted with a 20% total body surface area (TBSA) full-chickness scald injury followed by S. aureus challenge, then guanosine triphosphatecyclohydrolase I (GTP-CHI) mRNA expression and biopterin levels in liver, kidneys, lungs and heart were determined at 0. 5, 2, 6, 12 and 24 hours after S. aureus challenge. We found that after S. aureus challenge, GTP-CHI gene expressions and biopterin levels were markedly up-regulated in various tissues, and remained at high values up to 24 hours (P< 0. 05-0.01). Meanwhile, the organ function indexes, including serum alanine amimotransferase (ALT), aspartate aminotransferase (AST), creatinine (Cr), MB isoenzyme of creatine kinase (CK-MB), levels and pulmonary myeloperoxidase (MPO) activities significantly increased at 24 hours postburn, and the multiple organ dysfunction was aggravated by S. aureus challenge. Moreover, it was shown that cardiac GTP-CHI mRNA expression and renal BH4levels were positively correlated with CK-MB and Cr (r=0. 892, P=0. 0012 and r=0. 9423,P=0.0015, respectively). Conclusion: These results suggested that thermal injury combined with S. aureus challenge could induce de novo biosynthesis of biopterin, which acts as the most important cofactor of iNOS, might play a role in the development of multiple organ dysfunction syndrome secondary to postburn sepsis.

  2. Structural basis of biopterin-induced inhibition of GTP cyclohydrolase I by GFRP, its feedback regulatory protein.

    Science.gov (United States)

    Maita, Nobuo; Hatakeyama, Kazuyuki; Okada, Kengo; Hakoshima, Toshio

    2004-12-01

    GTP cyclohydrolase I (GTPCHI) is the rate-limiting enzyme involved in the biosynthesis of tetrahydrobiopterin, a key cofactor necessary for nitric oxide synthase and for the hydroxylases that are involved in the production of catecholamines and serotonin. In animals, the GTPCHI feedback regulatory protein (GFRP) binds GTPCHI to mediate feed-forward activation of GTPCHI activity in the presence of phenylalanine, whereas it induces feedback inhibition of enzyme activity in the presence of biopterin. Here, we have reported the crystal structure of the biopterin-induced inhibitory complex of GTPCHI and GFRP and compared it with the previously reported phenylalanine-induced stimulatory complex. The structure reveals five biopterin molecules located at each interface between GTPCHI and GFRP. Induced fitting structural changes by the biopterin binding expand large conformational changes in GTPCHI peptide segments forming the active site, resulting in inhibition of the activity. By locating 3,4-dihydroxy-phenylalanine-responsive dystonia mutations in the complex structure, we found mutations that may possibly disturb the GFRP-mediated regulation of GTPCHI. PMID:15448133

  3. Biopterin in Parkinson's disease.

    OpenAIRE

    Moore, A P; Behan, P O; Jacobson, W.; Armarego, W L

    1987-01-01

    Tetrahydrobiopterin is an essential co-factor in the natural synthesis of dopamine. Oral tetrahydrobiopterin was given in small doses to four patients with early Parkinson's disease but had no discernible effect.

  4. Determination of marker pteridins and biopterin reduced forms, tetrahydrobiopterin and dihydrobiopterin, in human urine, using a post-column photoinduced fluorescence liquid chromatographic derivatization method

    Energy Technology Data Exchange (ETDEWEB)

    Canada-Canada, Florentina, E-mail: floricanada@gmail.com [Department of Analytical Chemistry, University of Extremadura, 06071 Badajoz (Spain); Espinosa-Mansilla, Anunciacion; Munoz de la Pena, Arsenio; Mancha de Llanos, Alicia [Department of Analytical Chemistry, University of Extremadura, 06071 Badajoz (Spain)

    2009-08-19

    A liquid chromatographic method for the simultaneous analysis of marker pteridins and biopterin reduced forms, in urine samples is proposed. A Zorbax Eclipse XDB-C18 column was used for the chromatographic separation, using a 98/2 (v/v), citrate buffer (pH 5.5)-acetonitrile mobile phase, in isocratic mode. A post-column photoderivatization was carried out with an on-line photoreactor, located between a diode array detector (DAD) and a fast scanning fluorescence detector (FSFD). Neopterin (NEO), biopterin (BIO), pterin (PT) and dihydrobiopterin (BH2) were determined by measuring native fluorescence, using the photoreactor in OFF-mode, and tetrahydrobiopterin (BH4) was determined by measuring of the induced fluorescence of the generated photoproducts, using the photoreactor in ON-mode. In addition, Creatinine (CREA), as a reference of metabolites excrection in urine, was simultaneously determined using the DAD detector. Detection limits were 0.2, 13.0, 0.3, 0.3 and 3.5 ng mL{sup -1}, for NEO, BH2, BIO, PT and BH4, respectively, and 0.4 {mu}g mL{sup -1} for CREA. Ratio values for NEO/CREA, PT/CREA, BH4/CREA, BH2/CREA, NEO/BIO and BIO{sub total}/CREA, in urine samples, of healthy children and adults, phenylketonuric children and infected mononucleosis children, are reported. A comparative study, about the mean values obtained for each of the compounds, by the present procedure and by the classical iodine oxidation method (Fukushimas method), has been performed, in urine samples belonging to healthy volunteers. The values obtained were BH4/CREA: 0.41, BH2/CREA: 0.31 and BIO{sub total}/CREA: 0.73, by the proposed method, and BH4/CREA: 0.35, BH2/CREA: 0.20 and BIO{sub total}/CREA: 0.48, by iodine oxidation method.

  5. Determination of marker pteridins and biopterin reduced forms, tetrahydrobiopterin and dihydrobiopterin, in human urine, using a post-column photoinduced fluorescence liquid chromatographic derivatization method

    International Nuclear Information System (INIS)

    A liquid chromatographic method for the simultaneous analysis of marker pteridins and biopterin reduced forms, in urine samples is proposed. A Zorbax Eclipse XDB-C18 column was used for the chromatographic separation, using a 98/2 (v/v), citrate buffer (pH 5.5)-acetonitrile mobile phase, in isocratic mode. A post-column photoderivatization was carried out with an on-line photoreactor, located between a diode array detector (DAD) and a fast scanning fluorescence detector (FSFD). Neopterin (NEO), biopterin (BIO), pterin (PT) and dihydrobiopterin (BH2) were determined by measuring native fluorescence, using the photoreactor in OFF-mode, and tetrahydrobiopterin (BH4) was determined by measuring of the induced fluorescence of the generated photoproducts, using the photoreactor in ON-mode. In addition, Creatinine (CREA), as a reference of metabolites excrection in urine, was simultaneously determined using the DAD detector. Detection limits were 0.2, 13.0, 0.3, 0.3 and 3.5 ng mL-1, for NEO, BH2, BIO, PT and BH4, respectively, and 0.4 μg mL-1 for CREA. Ratio values for NEO/CREA, PT/CREA, BH4/CREA, BH2/CREA, NEO/BIO and BIOtotal/CREA, in urine samples, of healthy children and adults, phenylketonuric children and infected mononucleosis children, are reported. A comparative study, about the mean values obtained for each of the compounds, by the present procedure and by the classical iodine oxidation method (Fukushimas method), has been performed, in urine samples belonging to healthy volunteers. The values obtained were BH4/CREA: 0.41, BH2/CREA: 0.31 and BIOtotal/CREA: 0.73, by the proposed method, and BH4/CREA: 0.35, BH2/CREA: 0.20 and BIOtotal/CREA: 0.48, by iodine oxidation method.

  6. Biopterin Status in Dogs with Myxomatous Mitral Valve Disease is Associated with Disease Severity and Cardiovascular Risk Factors

    DEFF Research Database (Denmark)

    Reimann, M. J.; Häggström, J.; Mortensen, A.; Lykkesfeldt, J.; Moller, J. E.; Falk, T.; Olsen, L. H.

    2014-01-01

    oxidized to the biologically inactive form dihydrobiopterin (BH2). Thus, plasma concentrations of BH2 and BH4 may reflect ED and oxidative stress. Objective: To determine plasma concentrations of BH2 and BH4 in dogs with different degrees of MMVD. Animals: Eighty-four privately owned dogs grouped according......] because of MMVD [group C]). Methods: Dogs underwent clinical examination including echocardiography. Plasma concentrations of BH2 and BH4 were measured using high-performance liquid chromatography with fluorescence detection. Results: Higher plasma BH4 and BH2 concentrations were found with dogs in CHF...

  7. Increased bioprotein production in rats with tumors induced by radon inhalation and benzonaphtoflavone administration

    International Nuclear Information System (INIS)

    Serial determinations of urinary biopterin were performed in rats during the development of lung tumors induced by radon inhalation and 5,6-benzonaphtoflavone administration. A striking increase in biopterin levels was observed in animals which developed single or multiple epidermoid carcinoma of the lung and this increase occurred several weeks before tumors could be detected radiographically. (author)

  8. Changes in tetrahydrobiopterin levels in endothelial cells and adult cardiomyocytes induced by LPS and hydrogen peroxide--a role for GFRP?

    Science.gov (United States)

    Kalivendi, Shasi; Hatakeyama, Kazuyuki; Whitsett, Jennifer; Konorev, Eugene; Kalyanaraman, B; Vásquez-Vivar, Jeannette

    2005-02-15

    Alterations in tetrahydrobiopterin (BH4) levels have significant consequences in vascular pathophysiology. However, the mechanisms regulating BH4 remain poorly understood. The activity of GTP cyclohydrolase I (GTPCH-I), the first enzyme in BH4 biosynthesis, is controlled by protein levels, posttranslational modifications and interaction with GTPCH-I feedback regulatory protein (GFRP). This work examined the correlation between GTPCH-I protein levels and activity and changes in BH4 in human endothelial cells (HAECs) and adult rat cardiomyocytes (ARCM). Changes in BH4 were stimulated with LPS in HAECs and ARCM, and with hydrogen peroxide in HAECs only. Biopterin production by HAECs and ARCM were attained with concentrations of LPS >1 microg/ml and responses were nonlinear with respect to LPS concentrations. Western blot analysis demonstrated that induction of biopterin synthesis in HAECs and ARCM by LPS does not entail augmentation of constitutive GTPCH-I protein levels. However, LPS diminished GFRP mRNA, suggesting that disruption of GTPCH-I:GFRP complex enhances de novo biopterin synthesis. Conversely, treatment with hydrogen peroxide increased GTPCH-I and GFRP mRNA levels in HAECs while depleting BH4 and GSH, which was counteracted by catalase. This indicates that GFRP may override increases in GTPCH-I protein inhibiting enzyme activity. This conclusion is further supported by depletion of biopterin in cells transiently transfected with GFRP. Thus, allosteric regulation of GTPCH-I activity in the cardiovascular system maybe an important mechanism regulating BH4 levels through GFRP signaling. PMID:15649650

  9. Parallel induction of tetrahydrobiopterin biosynthesis and indoleamine 2,3-dioxygenase activity in human cells and cell lines by interferon-gamma.

    Science.gov (United States)

    Werner, E R; Werner-Felmayer, G; Fuchs, D; Hausen, A; Reibnegger, G; Wachter, H

    1989-01-01

    In all of eight tested human cells and cell lines with inducible indoleamine 2,3-dioxygenase (EC 1.13.11.17) tetrahydrobiopterin biosynthesis was activated by interferon-gamma. This was demonstrated by GTP cyclohydrolase I (EC 3.5.4.16) activities and intracellular neopterin and biopterin concentrations. Pteridine synthesis was influenced by extracellular tryptophan. In T 24-cell extracts, submillimolar concentrations of tetrahydrobiopterin stimulated the indoleamine 2,3-dioxygenase reaction. PMID:2511835

  10. The effect of 2,4-diamino-6-hydroxy-pyrimidine on postburn Staphylococcus aureus sepsis in rats

    Institute of Scientific and Technical Information of China (English)

    Li Hongyun; Yao Yongming; Shi ZhiGuo; Dong Ning; Yu Yan; Lu Lianrong; Sheng Zhiyong

    2002-01-01

    GTP-cyclohydrolase I (GTP-CHI) is the first and rate-limiting enzyme for the de novo biosynthesis of biopterin. The present study was to observe the effect of 2,4-diamino-6-hydroxy-pyrimidine (DAHP),an inhibtor of GTP-CHI, on the development of postburn Staphylococcus aureus sepsis. Methods: 56 male Wistar rats were randomly divided into four groups as follows: normal control group (n= 10), scald control group(n= 10),pos tburn sepsis group (n= 20) and DA HP treatment group (n= 16). In the scald control group, rats were subjected to a 20% total body surface area (TBSA) Ⅲ° scald injury, then sacrificed at 24 hrs. In the postburn sepsis group (n=20), rats were inflicted with 20% TBSA Ⅲ° scald followed by Staphylococcus aureus challenge, and they were further divided into 2 and 6 hrs groups. In the DAHP treatment group (n= 16), animals were intraperitoneally injected with a dose of 1g/kg DAHP prior to Staphylococcus aureus challenge, and then further divided into 2, 6 hrs groups. Tissue samples from liver, kidneys, lungs and heart were collected to determine GTP-CHI, inducible nitric oxide synthase (iNOS) and tumor necrosis factor-α (TNF-α) mRNA expression. Meanwhile, biopterin and nitric oxide (NO) levels in these tissues were also measured. Results: After the scald injury followed by Staphylococcus aureus challenge, GTP-CHI mRNA expression and biopterin levels significantly elevated in various tissues such as liver, heart, kidneys and lungs, so did the values of iNOS mRNA expression and NO formation (P<0.01). Pretreatment with DAHP could significantly reduce GTP-CHI/biopterin induction (P<0. 05~0. 01), and the up-regulation of iNOS/NO was also suppressed. Furthermore, DAHP administration could also inhibit the gene expression of TNF-α. 2 hrs after septic challenge, TNF-α mRNA expression in liver, kidneys and lungs in DAHP-treated group were 35.7%, 37.3% and 33.0% of those in postburn septic group, respectively. Additionally, in animals without DAHP

  11. Reduced near-UV sensitivity in Phycomyces mutants affected in the biosynthesis of 6,7-dimethyl-8-ribitylllumazine

    International Nuclear Information System (INIS)

    Riboflavin-requiring mutants of Phycomyces blakesleeanus with defects in the genes, ribA, ribB, ribC and ribD were analyzed with respect to their contents of flavins, 6,7-dimethyl-8-ribityllumazine (DMRL) and pterins as well as their phototropic sensitivity. Strains were grown on minimal medium enriched with 10-6 M riboflavin (RB), and the concentrations of the respective pigments in sporangiophores were determined by HPLC. In strains A607 ribC401 and A641 ribC402 madA7 a loss of DMRL correlated with a loss of near-UV sensitivity. In general terms, the results suggest the participation of DMRL in photoreception, which does not necessarily imply DMRL as a photoreceptor chromophore. In more specific terms, the result could be understood on the basis of a UV/blue-light photorecptor, which includes besides a flavin also a lumazine-like chromophore. Mutants C318 ribAl and C323 ribA4 accumulated DMRL, the immediate precursor of RB, as well as biopterin and neopterin. Mutant C322 ribB contained normal amounts of DMRL and pterins. Mutant C324 ribD5 had reduced amounts of neopterin and biopterin. The fact that some of the RB-requiring mutants displayed abnormal amounts of pterins indicates a common regulation for the flavin and the pterin pathway. (Author)

  12. Screening for dopa-responsive dystonia in patients with Scans Without Evidence of Dopaminergic Deficiency (SWEDD).

    Science.gov (United States)

    De Rosa, Anna; Carducci, Claudia; Carducci, Carla; Peluso, Silvio; Lieto, Maria; Mazzella, Andrea; Saccà, Francesco; Brescia Morra, Vincenzo; Pappatà, Sabina; Leuzzi, Vincenzo; De Michele, Giuseppe

    2014-11-01

    The clinical diagnosis of Parkinson's Disease (PD) is not supported by Single Photon Emission Computed Tomography (SPECT) using dopamine transporter radioligand in 4-15 % of patients. It has been hypothesized that this phenomenon, named "Scans Without Evidence of Dopaminergic Deficiency" (SWEDD), may be an adult-onset dystonia. We investigated the hypothesis that these patients might be affected by Dopa-Responsive Dystonia (DRD). We enrolled eleven unrelated patients (8 F and 3 M) with clinical parkinsonism and normal [(123)I]FP-CIT SPECT. The GTP-cyclohydrolase1 (GCH1) gene was sequenced in all patients; urine biopterin and neopterin analysis was carried out in nine and oral phenylalanine (Phe) loading in seven. Neurological examination showed bradykinesia and resting/postural tremor in all patients, and rigidity in ten, suggesting a clinical diagnosis of PD. We detected mild dystonic signs in eight cases. In particular, five of them presented cranial dyskinesias. No mutation of the GCH1 gene was found. The results of the urine biopterin and neopterin analysis and the oral Phe loading did not reveal biochemical abnormalities suggestive of reduced GCH1 activity. We confirm that some clinical features, namely the presence of focal or segmental dystonia, suggest an adult-onset dystonia in SWEDD cases. However, we exclude DRD caused by GCH1 gene mutations in the present series. PMID:25182701

  13. Photooxidation of tetrahydrobiopterin under UV irradiation: possible pathways and mechanisms.

    Science.gov (United States)

    Buglak, Andrey A; Telegina, Taisiya A; Lyudnikova, Tamara A; Vechtomova, Yulia L; Kritsky, Mikhail S

    2014-01-01

    Tetrahydrobiopterin (H4 Bip) is a cofactor for several key enzymes, including NO synthases and aromatic amino acid hydroxylases (AAHs). Normal functioning of the H4 Bip regeneration cycle is extremely important for the work of AAHs. Oxidized pterins may accumulate if the H4 Bip regeneration cycle is disrupted or if H4 Bip autoxidation occurs. These oxidized pterins can photosensitize the production of singlet molecular oxygen (1)O2 and thus cause oxidative stress. In this context, we studied the photooxidation of H4 Bip in phosphate buffer at pH 7.2. We found that UV irradiation of H4 Bip affected its oxidation rate (quantum yield Φ300 = (2.7 ± 0.4) × 10(-3)). The effect of UV irradiation at λ = 350 nm on H4 Bip oxidation was stronger, especially in the presence of biopterin (Bip) (Φ350 = (9.7 ± 1.5) × 10(-3)). We showed that the rate of H4 Bip oxidation linearly depends on Bip concentration. Experiments with KI, a selective quencher of triplet pterins at micromolar concentrations, demonstrated that the oxidation is sensitized by the triplet state biopterin (3) Bip. Apparently, electron transfer sensitization (Type-I mechanism) is dominant. Energy transfer (Type-II mechanism) and singlet oxygen generation play only a secondary role. The mechanisms of H4 Bip photooxidation and their biological meaning are discussed. PMID:24773158

  14. Pigmentos de Triatomideos brasileiros

    Directory of Open Access Journals (Sweden)

    Gilberto G. Villela

    1975-01-01

    Full Text Available Os extratos em metanolºHCL e amônia-mercaptoetanol de conexivos de Triatomídeos examinados apresentaram espectros de absorção no visível com máximo único e nítido em 400 nm. A cromatografia em camada fina de silica-gel e em papel revelou a pesença de pterinas fluorescentes à luz ultravioleta filtrada em 365 nm a julgar pelos Rf comparados com os de pterinas padrões.Some Hemiptera (Triatomidae common in Brazil (Panstrongylus megistus, Triatoma brasiliensis, Rhodnius prolixus presented in the external tegument erythropterin, xanthopterin and possibly 3, 4, 7 - trioxypteridine. Most of the coloured extracts showed in the visible a sharp absorption at 400 nm suggesting its anthocyan character. Neither leuco nor biopterin were detected. The Rf was obtained by thin layer chromatography and the absorption measured spectrophotometrically in a Zeiss PQMII apparatus.

  15. Preparation and crystallization of the stimulatory and inhibitory complexes of GTP cyclohydrolase I and its feedback regulatory protein GFRP.

    Science.gov (United States)

    Maita, N; Okada, K; Hirotsu, S; Hatakeyama, K; Hakoshima, T

    2001-08-01

    Mammalian GTP cyclohydrolase I is a decameric enzyme in the first and rate-limiting step in the biosynthesis of tetrahydrobiopterin, which is an essential cofactor for enzymes producing neurotransmitters such as catecholamines and for nitric oxide synthases. The enzyme is dually regulated by its feedback regulatory protein GFRP in the presence of its stimulatory effector phenylalanine and its inhibitory effector biopterin. Here, both the stimulatory and inhibitory complexes of rat GTP cyclohydrolase I bound to GFRP were crystallized by vapour diffusion. Diffraction data sets at resolutions of 3.0 and 2.64 A were collected for the stimulatory and inhibitory complexes, respectively. Each complex consists of two GTPCHI pentamer rings and two GFRP pentamer rings, with pseudo-52 point-group symmetry. PMID:11468403

  16. E. coli QueD is a 6-carboxy-5,6,7,8-tetrahydropterin synthase†

    Science.gov (United States)

    McCarty, Reid M.; Somogyi, Árpád; Bandarian, Vahe

    2009-01-01

    To elucidate the early steps required during biosynthesis of a broad class of 7-deazapurine containing natural products, we have studied the reaction catalyzed by Escherichia coli QueD, a 6-pyruvoyl-5,6,7,8-tetrahydropterin synthase (PTPS) homolog possibly involved in queuosine biosynthesis. While mammalian PTPS homologs convert 7,8-dihydroneopterin triphosphate (H2NTP) to 6-pyruvoyltetrahydropterin (PPH4) in biopterin biosynthesis, E. coli QueD catalyzes the conversion of H2NTP to 6-carboxy-5,6,7,8-tetrahydropterin (CPH4). E. coli QueD can also convert PPH4 and sepiapterin to CPH4, allowing a mechanism to be proposed. PMID:19231875

  17. Expression, Purification and Characterisation of Tryptophan Hydroxylases

    DEFF Research Database (Denmark)

    Windahl, Michael Skovbo

    2007-01-01

    og co-substratet tetrahydrobiopterin spalter dioxygen (O2) så det ene oxygen-atom indsættes i aminosyren tryptophan. Der findes to forskellige former af TPH: TPH-1 findes flere forskellige steder i kroppen, mens TPH-2 findes i hjernen hvor det har afgørende betydning for mængden af serotonin i...... tetrahydro-biopterin og O2. Denne opdagelse er meget vigtig for udvikling af lægemidler, som individuelt kan regulere TPH-1s eller TPH-2s enzymaktivitet. Desuden er det vist, at tryptophan binder til TPH før tetrahydrobiopterin og O2. Den 3-dimensionelle struktur af TPH-1 er bestemt ved brug af...

  18. High dose sapropterin dihydrochloride therapy improves monoamine neurotransmitter turnover in murine phenylketonuria (PKU).

    Science.gov (United States)

    Winn, Shelley R; Scherer, Tanja; Thöny, Beat; Harding, Cary O

    2016-01-01

    Central nervous system (CNS) deficiencies of the monoamine neurotransmitters, dopamine and serotonin, have been implicated in the pathophysiology of neuropsychiatric dysfunction in phenylketonuria (PKU). Increased brain phenylalanine concentration likely competitively inhibits the activities of tyrosine hydroxylase (TH) and tryptophan hydroxylase (TPH), the rate limiting steps in dopamine and serotonin synthesis respectively. Tetrahydrobiopterin (BH4) is a required cofactor for TH and TPH activity. Our hypothesis was that treatment of hyperphenylalaninemic Pah(enu2/enu2) mice, a model of human PKU, with sapropterin dihydrochloride, a synthetic form of BH4, would stimulate TH and TPH activities leading to improved dopamine and serotonin synthesis despite persistently elevated brain phenylalanine. Sapropterin (20, 40, or 100mg/kg body weight in 1% ascorbic acid) was administered daily for 4 days by oral gavage to Pah(enu2/enu2) mice followed by measurement of brain biopterin, phenylalanine, tyrosine, tryptophan and monoamine neurotransmitter content. A significant increase in brain biopterin content was detected only in mice that had received the highest sapropterin dose, 100mg/kg. Blood and brain phenylalanine concentrations were unchanged by sapropterin therapy. Sapropterin therapy also did not alter the absolute amounts of dopamine and serotonin in brain but was associated with increased homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA), dopamine and serotonin metabolites respectively, in both wild type and Pah(enu2/enu2) mice. Oral sapropterin therapy likely does not directly affect central nervous system monoamine synthesis in either wild type or hyperphenylalaninemic mice but may stimulate synaptic neurotransmitter release and subsequent metabolism. PMID:26653793

  19. Influence of various forms of dialyzable leukocyte extracts on rat adjuvant arthritis

    International Nuclear Information System (INIS)

    Adjuvant-induced arthritis in rats is a chronic inflammatory disease, widely as an animal model for rheumatoid arthritis. In our study the effect of various fractions of dialyzable leukocyte extract (DLE): DLE I-molecular weight below 10 kDa (commercial preparation), DLE II-molecular weight below 5 kDa (suppressor fraction), DLE III-molecular weight 5-10 kDa on rat adjuvant-induced arthritis was studied. The adjuvant arthritic (AA) rats were treated with DLE fractions i.p. in solutions containing an active substance isolated from 12.5 x 106 and 6.25 x 106 leukocytes from day 1 (adjuvant injected) through day 18, every second day (total 9 times). Various markers in inflammation, immune function and joint destruction were evaluated: hind paw volume, serum hyaluronic acid, serum albumin and biopterin in urine. All these markers showed a significant improvement after using fraction DLE II in comparison with AA controls. Fractions DLE I and DLE III influenced only some markers of inflammation and immune function. Our results demonstrated a therapeutical effect of fraction DLE II on rat adjuvant-induced arthritis. (author). 22 refs, 2 figs, 2 tabs

  20. Muscle-directed gene therapy for phenylketonuria (PKU): Development of transgenic mice with muscle-specific phenylalanine hydroxylase expression

    Energy Technology Data Exchange (ETDEWEB)

    Harding, C.O.; Messing, A.; Wolff, J.A. [Univ. of Wisconsin, Madison, WI (United States)

    1994-09-01

    Phenylketonuria (PKU) is an attractive target for gene therapy because of shortcomings in current therapy including lifelong commitment to a difficult and expensive diet, persistent mild cognitive deficits in some children despite adequate dietary therapy, and maternal PKU syndrome. Phenylalanine hydroxylase (PAH) is normally expressed only in liver, but we propose to treat PKU by introducing the gene for PAH into muscle. In order to evaluate both the safety and efficacy of this approach, we have a developed a trangenic mouse which expresses PAH in both cardiac and skeletal muscle. The transgene includes promoter and enhancer sequences from the mouse muscle creatine kinase (MCK) gene fused to the mouse liver PAH cDNA. Mice which have inherited the transgene are healthy, active, and do not exhibit any signs of muscle weakness or wasting. Ectopic PAH expression in muscle is not detrimental to the health, neurologic function, or reproduction of the mice. Pah{sup enu2} hyperphenylalaninemic mice, a model of human PAH deficiency, bred to carry the transgene have substantial PAH expression in cardiac and skeletal muscle but none in liver. Muscle PAH expression alone does not complement the hyperphenylalaninemic phenotype of Pah{sup enu2} mice. However, administration of reduced tetrahydrobiopterin to transgenic Pah{sup enu2} mice is associated with a 25% mean decrease in serum phenylalanine levels. We predict that ectopic expression of PAH in muscle along with adequate muscle supplies of reduced biopterin cofactor will decrease hyperphenylalaninemia in PKU.

  1. A novel high-throughput screening assay for discovery of molecules that increase cellular tetrahydrobiopterin.

    Science.gov (United States)

    Li, Li; Du, Yuhong; Chen, Wei; Fu, Haian; Harrison, David G

    2011-09-01

    Tetrahydrobiopterin (BH(4)) is an essential cofactor for the nitric oxide (NO) synthases and the aromatic amino acid hydroxylases. Insufficient BH(4) has been implicated in various cardiovascular and neurological disorders. GTP cyclohydrolase 1 (GTPCH-1) is the rate-limiting enzyme for de novo biosynthesis of BH(4). The authors have recently shown that the interaction of GTPCH-1 with GTP cyclohydrolase feedback regulatory protein (GFRP) inhibits endothelial GTPCH-1 enzyme activity, BH(4) levels, and NO production. They propose that agents that disrupt the GTPCH-1/GFRP interaction can increase cellular GTPCH-1 activity, BH(4) levels, and NO production. They developed and optimized a novel time-resolved fluorescence resonance energy transfer (TR-FRET) assay to monitor the interaction of GTPCH-1 and GFRP. This assay is highly sensitive and stable and has a signal-to-background ratio (S/B) greater than 12 and a Z' factor greater than 0.8. This assay was used in an ultra-high-throughput screening (uHTS) format to screen the Library of Pharmacologically Active Compounds. Using independent protein-protein interaction and cellular activity assays, the authors identified compounds that disrupt GTPCH-1/GFRP binding and increase endothelial cell biopterin levels. Thus, this TR-FRET assay could be applied in future uHTS of additional libraries to search for molecules that increase GTPCH-1 activity and BH(4) levels. PMID:21693765

  2. Is tetrahydrobiopterin a therapeutic option in diabetic hypertensive patients?

    Directory of Open Access Journals (Sweden)

    Alberto Francisco Rubio-Guerra

    2010-09-01

    Full Text Available Alberto Francisco Rubio-Guerra1, Hilda Vargas-Robles2, Luz Maria Ramos-Brizuela1, Bruno Alfonso Escalante-Acosta21Metabolic Clinic, Hospital General de Ticomán SS DF, Mexico; 2Department of Molecular Biomedicine, Centro de Investigacion y de Estudios Avanzados del IPN, MexicoAbstract: Nitric oxide (NO is an important regulator of vascular tone, and is also an antithrombotic, anti-inflammatory, antiproliferative, and antiatherogenic factor. Endothelial function is altered in patients with coronary artery disease, stroke, and peripheral artery disease, and endothelial dysfunction correlates with the risk factor profile for a patient. Hypertension and type 2 diabetes are risk factors for vascular disease, and are both pathologies characterized by loss of NO activity. Indeed, endothelial dysfunction is usually present in diabetic and/or hypertensive patients. Tetrahydrobiopterin is an essential cofactor for the NO synthase enzyme, and insufficiency of this cofactor leads to uncoupling of the enzyme, release of superoxide, endothelial dysfunction, progression of hypertension, and finally, proatherogenic effects. Tetrahydrobiopterin is also an important mediator of NO synthase regulation in type 2 diabetes and hypertension, and may be a rational therapeutic target to restore endothelial function and prevent vascular disease in these patients. The aim of this paper is to review the rationale for therapeutic strategies directed to biopterins as a target for vascular disease in type 2 diabetic hypertensive patients.Keywords: tetrahydrobiopterin, endothelial dysfunction, diabetes, hypertension, oxidative stress, nitric oxide, eNOS synthase uncoupling

  3. The metabolic profiles of pterin compounds as potential biomarkers of bladder cancer-Integration of analytical-based approach with biostatistical methodology.

    Science.gov (United States)

    Kośliński, Piotr; Daghir-Wojtkowiak, Emilia; Szatkowska-Wandas, Paulina; Markuszewski, Marcin; Markuszewski, Michał J

    2016-08-01

    Cancer disease is the second leading cause of death across the world. The analysis of potential biomarkers of cancer can be useful in cancer screening or cancer diagnosis, and may provide valuable information on the disease risk and progression. Pterin compounds have been studied as candidates of potential biomarkers as their elevated levels have been reported in various cancer diseases. The objective of the study was to compare the profiles of six pterin compounds in urine of 35 healthy subjects and 46 patients diagnosed of bladder cancer with the use of HPLC coupled with fluorimetric detection. The results of the chromatographic analysis together with biostatistical-based approach showed, that the concentrations of pterin compounds in bladder cancer patients were higher as compared to healthy individuals, and statistically significant differences between patients and controls were reported for xanthopterin and isoxanthopterin. Moreover, gender-specific analysis revealed, that the concentrations of pterins in the group of women reached higher values in comparison to men. For metabolites juxtaposed in pairs, namely xanthopterin and isoxanthopterin as well as for neopterin and biopterin, we found significant positive correlations in the group of both, patients and healthy individuals. We therefore conclude, that chromatographic analysis with simultaneous extensive biostatistical-based interpretation of the metabolite profiles may provide deeper understanding of the relationships between pterin metabolites. The results do not prejudge the possibility of using pterin compounds in the diagnosis of bladder tumors. However the results may have an impact on the study of bladder cancer biomarkers. PMID:26992657

  4. Reduction of drosopterin content caused by a 45-nt insertion in Henna pre-mRNA of Drosophila melanogaster

    Institute of Scientific and Technical Information of China (English)

    WANG Qin; ZHAO ChunJiang; BAI LiHua; DENG XueMei; WU ChangXin

    2008-01-01

    Phenylalanine hydroxylase is assumed to be a key enzyme in drosopterin metabolism, but direct in vivo evidence to support this hypothesis is still absent. In the present study, we found a new natural reces-sive purple eye mutant of Drosophila melanogaster, Hnbp, which was a 45-nt insertion mutant in the second exon of Henna. The insertion resulted in a predicted protein with 15 additional amino acids as compared to the wild-type protein. Further analysis of protein structure showed that the predicted mutant protein probably had two more β-sheets, which may cause instability of two α-helices near the catalytic centre of the enzyme in the Biopterin-Hydroxyl binding domain. Hnbp mutant showed eye color defect with decrease of mRNA level, as well as drosopterin content reduction. The drosopterin defect could be fully rescued by expression of wild type Henna in the Hnbp background by GMR-GAL4 UAS-Henna/UAS-Henna:Hn/Hnbptransgenic line. All taken together, it can be concluded that the mu-tation in Henna is responsible for drosopterin reduction in mutant Hnbp, which provides key in vivo evidence to support the hypothesis that Henna is involved in drosopterin synthesis.

  5. Influence of various forms of dialyzable leukocyte extracts on rat adjuvant arthritis

    Energy Technology Data Exchange (ETDEWEB)

    Stancikova, Maria; Rovensky, Jozef; Blazickova, Stanislava [Research Institute of Rheumatic Diseases, Piestany (Slovakia); Pekarek, J.; Cech, Karel [Institute of Sera and Vaccines, Prague (Czech Republic)

    1994-12-31

    Adjuvant-induced arthritis in rats is a chronic inflammatory disease, widely as an animal model for rheumatoid arthritis. In our study the effect of various fractions of dialyzable leukocyte extract (DLE): DLE I-molecular weight below 10 kDa (commercial preparation), DLE II-molecular weight below 5 kDa (suppressor fraction), DLE III-molecular weight 5-10 kDa on rat adjuvant-induced arthritis was studied. The adjuvant arthritic (AA) rats were treated with DLE fractions i.p. in solutions containing an active substance isolated from 12.5 x 10{sup 6} and 6.25 x 10{sup 6} leukocytes from day 1 (adjuvant injected) through day 18, every second day (total 9 times). Various markers in inflammation, immune function and joint destruction were evaluated: hind paw volume, serum hyaluronic acid, serum albumin and biopterin in urine. All these markers showed a significant improvement after using fraction DLE II in comparison with AA controls. Fractions DLE I and DLE III influenced only some markers of inflammation and immune function. Our results demonstrated a therapeutical effect of fraction DLE II on rat adjuvant-induced arthritis. (author). 22 refs, 2 figs, 2 tabs.

  6. Pteridine fluorescence for age determination of Anopheles mosquitoes.

    Science.gov (United States)

    Wu, D; Lehane, M J

    1999-02-01

    The age structure of mosquito populations is of great relevance to understanding the dynamics of disease transmission and in monitoring the success of control operations. Unfortunately, the ovarian dissection methods currently available for determining the age of adult mosquitoes are technically difficult, slow and may be of limited value, because the proportion of diagnostic ovarioles in the ovary declines with age. By means of reversed-phase HPLC this study investigated the malaria vectors Anopheles gambiae and An. stephensi to see if changes in fluorescent pteridine pigments, which have been used in other insects to determine the age of field-caught individuals, may be useful for age determination in mosquitoes. Whole body fluorescence was inversely proportional to age (P 91%) up to 30 days postemergence, with the regression values: y = 40580-706x for An. gambiae, and y = 52896-681x for An. stephensi. In both species the main pteridines were 6-biopterin, pterin-6-carboxylic acid and an unidentified fluorescent compound. An. gambiae had only 50-70% as much fluorescence as An. stephensi, and fluorescent compounds were relatively more concentrated in the head than in the thorax (ratios 1:0.8 An. gambiae; 1:0.5 An. stephensi). The results of this laboratory study are encouraging. It seems feasible that this simpler and faster technique of fluorescence quantification could yield results of equivalent accuracy to the interpretation of ovarian dissection. A double-blind field trial comparing the accuracy of this technique to marked, released and recaptured mosquitoes is required to test the usefulness of the pteridine method in the field. PMID:10194749

  7. Reduction of Radiation-Induced Vascular Nitrosative Stress by the Vitamin E Analog γ-Tocotrienol: Evidence of a Role for Tetrahydrobiopterin

    International Nuclear Information System (INIS)

    Purpose: The vitamin E analog γ-tocotrienol (GT3) is a powerful radioprotector. GT3 reduces postradiation vascular peroxynitrite production, an effect dependent on inhibition of hydroxy-methylglutaryl-coenzyme A reductase. Hydroxy-methylglutaryl-coenzyme A reductase inhibitors mediate their pleiotropic effects via endothelial nitric oxide synthase that requires the cofactor tetrahydrobiopterin (BH4). This study investigated the effects of radiation on BH4 bioavailability and of GT3 on BH4 metabolism. Methods and Materials: Mice were exposed to 8.5 Gy of total body irradiation (TBI). Lung BH4 and total biopterin concentrations were measured 0, 3.5, 7, 14, and 21 days after TBI by use of differential oxidation followed by high-performance liquid chromatography. The effect of exogenous GT3 and BH4 treatment on postradiation vascular oxidative stress and bone marrow colony-forming units were assessed in vivo. The effect of GT3 on endothelial cell apoptosis and endothelial expression of guanosine triphosphate (GTP) cyclohydrolase 1 (GTPCH), GTPCH feedback regulatory protein (GFRP), GFRP transcription, GFRP protein levels, and GFRP-GTPCH protein binding was determined in vitro. Results: Compared with baseline levels, lung BH4 concentrations decreased by 24% at 3.5 days after TBI, an effect that was reversed by GT3. At 14 and 21 days after TBI, compensatory increases in BH4 (58% and 80%, respectively) were observed. Relative to vehicle-treated controls, both GT3 and BH4 supplementation reduced postirradiation vascular peroxynitrite production at 3.5 days (by 66% and 33%, respectively), and BH4 resulted in a 68% increase in bone marrow colony-forming units. GT3 ameliorated endothelial cell apoptosis and reduced endothelial GFRP protein levels and GFRP-GTPCH binding by decreasing transcription of the GFRP gene. Conclusions: BH4 bioavailability is reduced in the early postradiation phase. Exogenous administration of BH4 reduces postirradiation vascular oxidative stress. GT3