bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isolation and Characterization of Sepiapterin Reductase from Drosophila melanogaster
Authors: Yoon K.H. , Cha K.W. , Park S.I. , Yim J.J. 
Published: March 2013

Summary Sepiapterin reductase, an enzyme that catalyses the synthesis of tetrahydrobiopterin (BH4). was partially purified from Drosophila melanogaster using ammonium sulfate fractionation. Affi-gel blue chromatography and hydroxyapatite chromatography. The molecular weight of the enzyme determined by Ultrogel AcA44 column was 39,000. When the enzyme was subjected to polyacrylamide gel electrophoresis in SDS. a 38.000 MW species was found to be the major protein band. The Km values for sepiapterin and NADPH were determined to he 75.4 µM. and 14 µM, respectively. The optimal temperature and pH for the reaction were 30°C and pH 5.7-6.7. The half-life of the activity was 30 minutes when treated at 48°C The enzyme was markedly inhibited by tri-and tetravalent cations. Fe3+ . Sn4+ and divalent cation. Cd2+ . It was found that pyrimidodiazcpine (a homopterin) and 2.4-diamino-6.7-diisopropyl caused the reduction of sepiapterin reductase activity by about 50% at the concentration of 0.1 mM. Among the neurotransmitters and their precursors tested. 3 mM concentrations of melatonin and N-acetylserotonin inhibited the enzyme activity completely. In addition to sepiapterin. the enzyme uses rather broad spectrum of carbonyl compounds as substrate including menadione. p-nitrohenzaldehyde, and various dicarhonyl compounds
Folinic Acid Enhanced Cytotoxicity of Fluoropyrimidines In Human Breast Cancer Cells
Authors: Mandelbaum-Shavit Frederika 
Published: March 2013

Summary This report describes the effects of the natural diastereoisomer of 5-formyltetrahydrofolate (6S)- and of the mixture of both the natural and unnatural diastereoisomers (6RS)-5-HCO-H4PteGlu (folinate) on the cytotoxicity of 5-fluoro-2′-deoxyuridine (FdUrd) and 5-fluorouracil (FUra) in MCF-7 and MDA-MB 231. human breast cancer cell lines. Continuous exposure of exponentially growing cells to various concentrations of FUra for 72 h caused a 50% inhibition of growth with lC50 at concentrations of 3.40± 0.16 and 29± 1.40 11M in MCF-7 and MDA-MB 231. respectively. Preincubation of the cells for 24 h with (6S)-5-CHO-H4PteGlu (5 µM) prior to addition of FUra decreased the IC50 values by 2.4-2.6-fold in both cell lines. A quantitatively similar effect was achieved by preincubation with ]() µM of (6RS)-5-HCO-H4PteGlu. The cytotoxicity of FdUrd was markedly more pronounced than that of FUra exhibiting IC50, values at a range of 0.045- 0.050 µM for both cell lines. Preincubation with (6S)-5-HCO-H4PteGlu increased the susceptibility to the drug by about 3.5-fold. The optimal dose of (6S)-5-CHO-H4PteGlu for achieving the lowest IC50 value for FdURd in MCF-7 cells was 5 µM. whereas that in MDA-MB 231 was 20 µM. Similar increase of the cytotoxicity of FdUrd was obtained with about a 2-fold higher concentration of (6RS)-5-HCO-H4PteGlu. Cells pretreated lor 24 h with FUra or FdUrd respectively. exhibited enhanced incorporation of [3H] thymidine into the TCA-precipitable fraction . Presence of (6S)-5-HCO-H4PteGlu (10 µM) doubled the amount of incorporated thymidine. which reflects depletion of intracellular thymidylate pools due to enhanced formation and stabilization of the complex formed between thymidylate synthase. flouorodeoxydylate and 5.1.0-methylenetetrahydrofolate.
Immune Activation after Apicoectomy: Comparison between Patients with and without Prophylactic Antibiotic Therapy
Authors: Andersson Ch. , Bernhart Th. , Hönlinger M. , Mailath G. , Wachter H. , Fuchs D. 
Published: March 2013

Summary In humans neopterin concentrations represent a sensItive index of cell-mediated immune activation. In a previous study, we found significantly increasing neopterin concentrations in patients after dental extractions. In this study, we investigated whether prophylactic antibiotic treatment of patients influenced the course of neopterin levels in patients with apicoectomy. Urinary neopterin concentrations were monitored in 23 patients with apicoectomy in the front region. Urine samples were collected before and on days 1, 3, 5, 7, 9 after apicoectomy. Six patients received antibiotic therapy, 17 were without such treatment. We found that average neopterin concentrations increased preferentially in patients not treated with antibiotics whereas pateints treated with antibiotics showed only a moderate increase of neopterin levels which returned to normal within three days. We conclude that antibiotic treatment is able to reduce immune activation which is frequently seen in patients after apicoectomy, and we assume this maybe also true in patients after dental extractions. Most likely transient bacteraemia is the cause of immune activation in such patients. However, an inhibitory influence of antibiotics on cytokine cascades cannot be ruled out.
Are Disturbances of Zinc Metabolism in Human Immunodeficiency Virus Type I (HIV-I) Infection Caused By Immune Activation?
Authors: Melichar B. , Zangerle R. , Artner-Dworzak E. , Wachter H. , Fuchs D. 
Published: March 2013

Summary The activation of the immune system is associated with profound alteration of zinc metabolism. In human immunodeficiency type 1 (HIV-l) infection serum zinc is frequently decreased. To investigate a potential role of immune system activation on urinary zinc wasting, we compared urinary zinc and l1eopterin levels in 52 patients with HIV-J infection. In addition, serum zinc was studied in 25 of the patients. We confinned earlier reports of decreased serum zinc levels in the patients. As expected, urinary neopterin was significantly increased in HIV-l infection, the highest values being reached in AIDS patients. Urinary zinc concentrations were not statistically different between patients and controls. However, a positive correlation existed between urinary zinc and neopterin levels and between neopterin and zinc clearance coefficient in patients with more advanced stages of HIV infection. No correlation between serum zinc and urinary neopterin or urinary zinc was found. The data indicate that, in addition to malabsorption, chronic immune activation may contribute to the development of zinc deficiency by urinary zinc wasting.
Immune Activation and HIV-1 Viraemia In an Asymptomatic Paediatric Patient
Authors: Zaknun D. , Neugebauer J. , Soelder B. , Dierich M.P. , Wachter H. , Fuchs D. 
Published: March 2013

Summary Immune stimulation due to secondary infection may enhance HIV replication and viraemia, since cellular activation of CD4+T-cells is required for viral replication. We describe a case of an 18 months old child, exposed intrauterinely to human immunodeficiency virus type 1 (HIV -1). During a period of various infections, which was followed by transient viraemia, decrease of CD4 + T -lymphocytes and increase of neopterin concentrations was registered. Disease progression may have occured due to activation of latent HIV-l in CD4+ T -lymphocytes/macrophages by secondary infections.
Neopterin, β2-Microglobulin, Tryptophan and Kynurenine In Sporadic Amyotrophic Lateral Sclerosis
Authors: Westarp Martin E. , Fuchs Dietmar , Westarp Maria P. , Wachter Helmut , Kornhuber Hans-Helmut 
Published: March 2013

Summary In 62 patients diagnosed as sporadic amyotrophic lateral sclerosis (sALS), we quantitated serum concentrations of neopterin, β2-microglobulin. kynurenine and tryptophan. A linear increase with age was demonstrated by neopterin more than by β2-microglobulin, whereas neither parameter corresponded to individual progression or duration of disease at the time of examination. All serum (n = 79) and cerebrospinal fluid (CSF, n = 11 patients) concentrations remained within reference limits, and serum neopterin always exceeded CSF neopterin. Serum neopterin was not elevated in sALS. and we observed no correlation between circulating IgG isotype concentrations and serum neopterin. Total duration of sALS. as measured in months from the first clinical signs or symptoms to death, seemed. however. to inversely correlate with the mean patient serum neopterin before and after correction for age, and in the absence of any neoplastic process. If confirmed in a larger number of sALS patients, this would parallel a reportedly negative association of CSF neopterin and survival in human immunodeficiency virus (HIV1) infection.
Plasma Nitrate and Pteridine Levels in Experimental Bacteremia in Baboons
Authors: Strohmaier Wolfgang , Werner Ernst R. , Redl Heinz , Wachter Helmut , Schlag Gunther 
Published: March 2013

Summary Using a recently developed model of bacterially induced sepsis in baboons, we studied the time courses of pteridine and nitrate levels in plasma with regard to the dose of Escherichia coli. Eight animals were given a 2 h infusion of 2X 10" Colony Forming Units live E. coli/kg BW (group LOW), and six others 2X 10" CFU/kg BW (group HIGH). Endotoxin levels and, consequently, the TNF-a, IL-8, and IL-6 concentrations clearly corresponded with the infused amount of live E. coli. The neopterin/creatinine ratio increased in both groups up to 24 h, but was more pronounced in the HIGH group. In contrast, the biopterin/creatinine ratio increased in the HIGH group, but remained unchanged in the LOW group. Plasma nitrate levels remained at baseline (::::: 20 Ilmol!l) up to 4 h, but then increased three- to fourfold within the next 4 h and remained elevated in the HIGH group. In group LOW, the concentrations were unchanged throughout the observation period.
Glyceryl-Ether Monooxygenase [EC 1.14.16.5J Part VIII. Probing the Nature of the Active Site
Authors: Taguchi Hiroyasu , Paal Bela , Armarego Wilfred L.F. 
Published: March 2013

Summary The V /K kinetic parameters for glyceryl-ether monooxygenase with 3-1 '-n-alkoxypropane-I,2-diols having alkyl sidechains varying from Cll to C22 (lb-k, 2a and b, and 3d) were determined. Maximum activity was found with the CI6 ethers, dropping almost to zero with ethers that have sidechains shorter than Cl2 and longer than C19. The thioether analogues with C16 and CI8 sidechains were poorer substrates than the respective oxygen ethers by one order of magnitude. The kinetic parameters for 2-1 '-n-hexadecyloxy- (6a) and 2-1 '-n-octadecyloxy- (6d) ethanol revealed that they were also better substrates than the respective thio-ethers by one order of magnitude and with these compounds those with C16 sidechains were better substrates than the C 18 analogues. L2-bis-3-1 '-n-Hexadecyloxypropan-3-01 (3c) and 1,3-bis-3- 1'-n-hexadecyloxypropan-3-01 and 2- 01 (4a) were inactive but 3-1'-n-hexadecyloxy- 2-methoxypropan-I-ol (3b) and 3-1'-n-hexadecyloxy-l-methoxypropan-2-01 (4b) which have one long fatty chain were viable substrates because they possessed a free hydroxy group, but the ethers (6b, c and e), (7c and d) and (5) which do not have a free hydroxy group were inactive. These data, taken with those reported previously, have allowed us to postulate a model for the active site of the alkyl-ether substrates of the monooxygenase and to define the contours of the hydrophobic and hydrophilic pockets.
Neopterin in Septic Arthritis
Authors: Koberg K. , Schälicke S. , Klosterhalfen B. , Peters K.M. 
Published: March 2013

Summary Despite its low incidence septic arthritis remains a serious problem in orthopaedic practice. General or local immunosuppression predisposes for septic arthritis. Thus we see an increasing incidence in elderly patients, in patients suffering from rheumatic diseases and after alloplastic arthroplasty of the hip and of the knee. In septic arthritis the first line of host defense mechanisms is overwhelmed and bacterial multiplication proceeds within the joint. The pathogens found are in 50% to 75% of cases Staphylococci and in 15% to 20% Streptococci. Histologically we initially find an edema of the synovial membrane and a dramatic polymorph-nuclear-cell infiltration. After developing all signs of inflammation, a persistent purulent effusion accumulates and cartilage and bone destruction ensues as a result of proteolytic enzyme activity released from the bacteria and the polymorph nuclear leukocytes. Modern therapy consists of early surgical intervention (synovectomy, debridement) combined with local and systemic antibiotic treatment. The early intervention is one of the main factors for successful management. Thus the interest of early detection of septic arthritis is obvious. The production of neopterin can be related to the activity of the specific antibacterial cell mediated immune response. In the current, study weexamined neopterin levels in 12 patients with septic arthrits and in 8 patients with an infected prosthesis. The results were related to a new inflammation marker (PMN-elastase) and to 4 other 'classical' inflammation markers (ESR, leukocytes, fibrinogen and C-reactive protein). All markers showed a high sensitivity in the detection of septic arthritis. 10 patients with septic arthritis and 5 patients with an infected prosthesis showed pathological neopterin levels > 10 nmol/l.
Urinary Neopterin Levels as an Indicator of Disease Activation in Behçet’s Disease
Authors: Altindağ Z. , Şahin G. , Akpek G. , Y. Koç , Işimer A. , Kansu E. , Duru S. 
Published: March 2013

Summary Behçet’s Disease (BD) is a multisystem inflammatory disorder characterized by recurrent oral and genital ulcerations with uveitis. Clinical features are the only diagnostic and follow up parameters and there is no unique laboratory test to indicate both diagnosis and disease activity. We studied urinary neopterin levels by using high performance liquid chromatography in 21 consecutive patients with Behçet’s Disease in clinically active (n = 13) and inactive (n = 8) phase of the disease and in 14 healthy controls to investigate the correlation between this immunologic parameter and the disease status. In comparison to inactive phase, significantly higher urinary neopterin levels were found in active period (p<O.05). Mean urinary neopterin levels were 210.83 ± 157.19 vs 138.85 ± 56.99 I-imol neopterin/mol creatinine in active and inactive t1hase respectively (p<O.05). There was no significant difference between inactive phase and control values. In only 2 patients, both active and inactive phase urine neopterin levels could be measured in the same individual and increased neopterin levels were also determined in the active phase of disease. In conclusion, urinary neopterin levels were found to be elevated in active period and can be considered as an active phase marker in BD. Larger study groups with own controls of BD patients and other vasculitic disease controls are required before the final judgement.
Control of Melanogenesis In the Human Epidermis by the Redox-Status of Tetrahydrobiopterins
Authors: Schallreuter-Wood Karin U. , Wood John M. 
Published: March 2013

Summary Activity of tyrosinase directly controls melanogenesis in the human epidermis. Recently, it has been shown that the biosynthesis and recycling of (6R)L-erythro 5,6,7,8 tetrahydrobiopterin (6-BH4) plays a central role in regulating the supply of L-tyrosine, the substrate for tyrosinase. In this report, we present evidence that 6-BH4 and other tetrahydropterins, have the capacity to regulate tyrosinase activity directly by a specific uncompetitive mechanism. This fine control of tyrosinase activity/melanogenesis in the human epiidermis depends on the redox equilibrium 6-BH4 ↔ dihydropterin ↔ 6-biopterin. The accumulation of 6-biopterin is cytotoxic to normal human melanocytes.
Homology Cloning of GTP-cydohydrolase I from Fungi and Plants by Reverse-transcription PCR Using a General Set of Degenerate Primers
Authors: Maier Josef , Werner Thomas , Ninnemann Helga 
Published: March 2013

Summary Unconjugated pteridines are present in fungi, algae and plants. However, the functions of pteridines in these organisms are not thoroughly investigated. The biosynthesis follows the same steps as were shown for animals and eubacteria. One possible function of pteridines in these organisms is participation in blue-light reception. To analyze this or other functions of pteridines it would be useful to inhibit pteridine synthesis specifically by genetic engineering. GTP-cyclohydrolase I is the primary enzyme of tetrahydrobiopterin and folic acid biosynthesis. A comparison of amino acid sequences of GTP-cyclohydrolase I (EC 3.5.4.16) previously known from various species allowed the construction of degenerate primers, based on highly conserved regions. The same consensus primers are able to bind to cDNAs of unrelated eukaryotes. By reverse-transcriptase PCR cDNAs of the conserved C-terminal part of the fungi Neurospora and Phycomyces, the phytoflagellate Euglena and the higher plant Mucuna hassjoo were amplified and cloned. Similarities between the sequences agreed with the evolutionary relationship of the investigated organisms. Various regions strictly conserved between unrelated eukaryotes and bacteria were observed, which could be essential for the function of GTP-cyclohydrolase I.
Experimental Study Evaluating the Effect of Combined Methotrexate and Fluorouracil Therapy on Anemia in Mice With L1210 Lymphoid Leukemia
Authors: Graczyk Julita 
Published: March 2013

Summary Combined methotrexate (MTX) and fluorouracil (FU) has heen used for many years to treat neoplastic diseases. However, clinical and laboratory snldies are still carried out to explain the changes that the therapeutic and toxic effects undergo when MTX and FU are used as a combined therapy. The schedules of combined therapy used so far have either proved not very effective in retrospective assessment, or caused severe tOJ{jc symptoms. Antineoplastic drugs damage the matrix cells of bone mar· row; the effect of commonly used doses more frequently concerns immature forms of blood morphotic elements. Methotrexate belongs to the group of drugs with very potent toxic effect on mOlphotic elements of peripheral blood; the effect of fluorouracil is weaker. Methotrexate causes anemia due to the deficiency of folic acid. For correct metabolism of folic acid, cyanocobaJamin is necessary. With deficiency, or lack of cyanocobalamin, the process is disturbed and a marked decrease of folic acid concentration in erythrocytes occurs. The main circulating and accumulated folate is N 5 -methyltetrahydrofolate which is metabolically inactive itself. In the presented study the morphotic elements were determined iI1 mice inoculated i.p. with LIllO lymphoid leukemic cells. The determinations were carried out on the 14rh day after LIllO inoculation. In untreated animals a decrease of hemoglobin, hematocrit and erythrocyte count values took place as compared with the values observed in healthy mice. 3 schedules of cytostatics administration were used: MTX was administered lh before FU, MTX and FU were adrninistered simultaneously and FU was administered lh before MTX. It has been demonstrated that in mice inoculated with L1210 leukemia anemia was the least pronounced after the combined treatment schedule involving the adrninistration of MTX prior to FU. The indicators of folic acid deficiency in serum and erythrocytes (i.e. NS-methyltetrahydrofolate levels), and cya.-lOcobalamin deficiency in serum in. mic.e with LIllO lymphatic leukemia are aggravated after instituting the combined therapy schedules involving the administration of FU as the first drug, or simultaneous administration of MTX and FU.
Tetrahydrobiopterin Synthesis in Rat Cardiac Myocytes; An Event Required for Cytokine-induced NO Generation
Authors: Hattori Yoshiyuki , Nakanishi Nobuo , Gross Steven S. , Kasai Kikuo 
Published: March 2013

Summary
Cardiac myocytes are known to express the high-capacity inducible isoform of nitric oxide (NO) synthase (iNOS). Since tetrahydrobiopterin (BH4) is an essential cofactor for NO formation, we investigated whether BH4 synthesis is required for cytokine-induced NO production in cultutred rat cardiac myocytes. The total biopterin content of untreated cardiac myocytes was below our limit of detection. However, treatment with inter-leukin-1α. and interferon-γ (IL-1/IFN) caused a significant rise in biopterin levels and induced NO synthesis. iNOS mRNA and GTP cyclohydrolase I (GTPCH) mRNA were induced by IL-1/IFN in parallel. 2,4-Diamino-6-hydroxypyridine (DAHP), a selective inhibitor of GTPCH, inhibited both the increase in cellular levels of BH4 as well as the concomitant formation of NO caused by IL-1/IFN. This inhibition by DAHP was reversed by coaddition of sepiapterin which is a substrate for BH4 synthesis. Thus BH4 synthesis is an absolute requirement for induction of NO synthesis by cytokines in cardiac myocytes.
Neopterin and Kynurenine in Mesangioproliferative Glomerulonephritis
Authors: Martinsons Agris , Rudzite Vera , Widner Bernhard , Fuchs Dietmar 
Published: March 2013

Summary Serum kynurenine and neopterin concentrations were determined in patients with chronic mesangioproliferative glomerulonephritis with normal renal function and in patients with chronic renal failure. Significantly increased kynurenine and neopterin levels have been observed in 28% of mesangioproliferative glomerulonephritis patients. In vitro, interferon-y induces the formation of neopterin in human monocytes/macrophages. Also the degradation of tryptophan via the kynurenine pathway is induced by interferon-yo Our data show increased kynurenine and neopterin concentrations in serum in the case of mesangioproliferative glomerulonephritis. There was a positive correlation between serum kynurenine and neopterin levels. The same association between kynurenine and neopterin have been found in patients with chronic renal failure . At the end stage of renal disease, elevated levels of kynurenine and neopterin corresponded to the decrease of renal functions. In 59% of patients with mesangioproliferative glomerulonephritis, we detected also pyridoxal-5-phosphate deficiency concomitant with the increase of serum concentration of kynurenine. L-tryptophan peroral loading test could be useful for differentiation the both causes of hyperkynureninemia.
6R-L-erythro-Tetrahydrobiopterin Triggers Serotonin Release with 5HT-loaded RBL2H3 Cells, a Rat Mast Cell Line
Authors: Nakazawa Naomi , Yamamoto Kazumasa , Nagano Mutsumi , Oguro Kazuya , Nakanishi Nobuo , Hasegawa Hiroyuki 
Published: March 2013

Abstract
A new function of tetrahydrobiopterin (BH4) was demonstrated in vitro in which BH4 stimulated serotonergic cells to release serotonin (5HT). RBL2H3 cells were pre-loaded with serotonin at 100 μM for 6 hours. The cells were able to release serotonin in response to either 30 mM KCl or 30 nM A23187 up to 2.26±2.06% (n=15) or 9.75± 1.38% (n=15 ), respectively. On exposure to 6R-L-erythrotetrahydrobiopterin (6RBH4) at 100 μM, the 5HT-Ioaded cells secreted serotonin up to 8.13± 1.43% of the cellular 5HT within 60 min. The effect was a concentration dependent response and the half maximum output was observed at 1 nM or lower. Sepiapterin (> 10 μM) caused minimal release and 6S-L-erythro-tetrahydrobiopterin (6SBH4,≤0 .4 mM) did not cause significant release. The results suggest that the effect of 6RBH4 was highly stereospecific and that it worked extracellularly.