bluuebunny/crossref_metadata_2025 huggingface dataset:
Supplementation of a grape seed and grape marc meal extract decreases activities of the oxidative stress-responsive transcription factors NF-κB and Nrf2 in the duodenal mucosa of pigs
Authors: Gessner Denise K , Fiesel Anja , Most Erika , Dinges Jennifer , Wen Gaiping , Ringseis Robert , Eder Klaus
Published: March 2013

Background

In pigs, enteric infections and the development of gut disorders such as diarrhoea are commonly observed, particularly after weaning. The present study investigated the hypothesis that feeding a grape seed and grape marc extract (GSGME) as a dietary supplement has the potential to suppress the inflammatory process in the small intestine of pigs by modulating the activities of NF-κB and Nrf2 due to its high content of flavonoids.

Methods

Twenty-four crossbred, 6 weeks old pigs were randomly assigned to 2 groups of 12 animals each and fed nutritionally adequate diets without or with 1% GSGME for 4 weeks.

Results

Pigs administered GSGME had a lower transactivation of NF-κB and Nrf2 and a lower expression of various target genes of these transcription factors in the duodenal mucosa than control pigs (P < 0.05). Concentrations of α-tocopherol and thiobarbituric acid reactive substances (TBARS) in liver and plasma and total antioxidant capacity of plasma and relative mRNA abundances of NF-κB and Nrf2 target genes in the liver did not differ between the two groups. However, the ratio of villus height:crypt depth and the gain:feed ratio was higher in the pigs fed GSGME than in control pigs (P < 0.05).

Conclusions

This study shows that dietary supplementation of a polyphenol rich GSGME suppresses the activity of NF-κB in the duodenal mucosa of pigs and thus might provide a useful dietary strategy to inhibit inflammation in the gut frequently occurring in pigs. Feeding GSGME did not influence vitamin E status and the antioxidant system of the pigs but improved the gain:feed ratio. In overall, the study suggests that polyphenol-rich plant extracts such GSGME could be useful feed supplements in pig nutrition, in order to maintain animal health and improve performance.
BiNoM 2.0, a Cytoscape plugin for accessing and analyzing pathways using standard systems biology formats
Authors: Bonnet Eric , Calzone Laurence , Rovera Daniel , Stoll Gautier , Barillot Emmanuel , Zinovyev Andrei
Published: March 2013

Background

Public repositories of biological pathways and networks have greatly expanded in recent years. Such databases contain many pathways that facilitate the analysis of high-throughput experimental work and the formulation of new biological hypotheses to be tested, a fundamental principle of the systems biology approach. However, large-scale molecular maps are not always easy to mine and interpret.

Results

We have developed BiNoM (Biological Network Manager), a Cytoscape plugin, which provides functions for the import-export of some standard systems biology file formats (import from CellDesigner, BioPAX Level 3 and CSML; export to SBML, CellDesigner and BioPAX Level 3), and a set of algorithms to analyze and reduce the complexity of biological networks. BiNoM can be used to import and analyze files created with the CellDesigner software. BiNoM provides a set of functions allowing to import BioPAX files, but also to search and edit their content. As such, BiNoM is able to efficiently manage large BioPAX files such as whole pathway databases (e.g. Reactome). BiNoM also implements a collection of powerful graph-based functions and algorithms such as path analysis, decomposition by involvement of an entity or cyclic decomposition, subnetworks clustering and decomposition of a large network in modules.

Conclusions

Here, we provide an in-depth overview of the BiNoM functions, and we also detail novel aspects such as the support of the BioPAX Level 3 format and the implementation of a new algorithm for the quantification of pathways for influence networks. At last, we illustrate some of the BiNoM functions on a detailed biological case study of a network representing the G1/S transition of the cell cycle, a crucial cellular process disturbed in most human tumors.
Genetic variants and their interactions in disease risk prediction – machine learning and network perspectives
Authors: Okser Sebastian , Pahikkala Tapio , Aittokallio Tero
Published: March 2013

A central challenge in systems biology and medical genetics is to understand how interactions among genetic loci contribute to complex phenotypic traits and human diseases. While most studies have so far relied on statistical modeling and association testing procedures, machine learning and predictive modeling approaches are increasingly being applied to mining genotype-phenotype relationships, also among those associations that do not necessarily meet statistical significance at the level of individual variants, yet still contributing to the combined predictive power at the level of variant panels. Network-based analysis of genetic variants and their interaction partners is another emerging trend by which to explore how sub-network level features contribute to complex disease processes and related phenotypes. In this review, we describe the basic concepts and algorithms behind machine learning-based genetic feature selection approaches, their potential benefits and limitations in genome-wide setting, and how physical or genetic interaction networks could be used as a priori information for providing improved predictive power and mechanistic insights into the disease networks. These developments are geared toward explaining a part of the missing heritability, and when combined with individual genomic profiling, such systems medicine approaches may also provide a principled means for tailoring personalized treatment strategies in the future.
Curcumin improves expression of SCF/c-kit through attenuating oxidative stress and NF-κB activation in gastric tissues of diabetic gastroparesis rats
Authors: Jin Qi-Hui , Shen Hong-Xia , Wang Hui , Shou Qi-Yang , Liu Qiang
Published: March 2013

Background

Diabetes mellitus is associated with many kinds of complications. Recent studies have shown that oxidative stress and inflammatory reactions have critical roles in the pathogenesis of diabetic gastroparesis. Curcumin is known to have antioxidant and anti-inflammatory properties. In the present study, we investigated the effect of curcumin on diabetic gastric motility in a Sprague Dawley rat model of type 1 diabetes mellitus.

Methods

Male SD rats were divided into a control group, a control group receiving curcumin, a diabetic group, and a diabetic group receiving curcumin. Diabetes was induced by intraperitoneal injection of streptozotocin. Curcumin (150 mg/kg) was given intragastrically for 6 weeks, and blood glucose levels and body weights were measured. Stomachs were excised for analysis of gastric emptying rates, and levels of oxidative stress. NF-κB, I-κB, and stem cell factor (SCF)/c-kit protein levels were assessed by western blot analysis, while the apoptosis of interstitial cells of Cajal (ICCs) was assessed by TUNEL staining.

Results

Curcumin-treated diabetic rats showed significantly improved gastric emptying rates [(59.4 ± 7.5)%] compared with diabetic rats [(44.3 ± 5.7)%], as well as decreased levels of MDA [21.4 ± 1.8 (nmol/mg)vs27.9 ± 2.1 (nmol/mg)], and increased SOD activity [126.2 ± 8.8 (units/mg)vs107.9 ± 7.5 (units/mg)]. On the other hand, the gastric emptying level in the control group was not significantly different from that in the control group receiving curcumin treatment. In addition, curcumin-treated diabetic rats showed significantly increased levels of SCF/c-kit protein in stomach tissues, inhibited I-κB degradation and NF-κB activation, and reduced ICC apoptosis index [(26.2 ± 4.1)%vs(47.5 ± 6.2)%], compared with the diabetic group.

Conclusion

Curcumin treatment improved gastric emptying by blocking the production of oxidative stress, abolishing NF-κB signal transduction and enhancing expression of SCF/c-kit in rats with diabetic gastroparesis.
Diabetic status and the relation of the three domains of glycemic control tomortality in critically ill patients: an international multicenter cohort study
Authors: Krinsley James S , Egi Moritoki , Kiss Alex , Devendra Amin N , Schuetz Philipp , Maurer Paula M , Schultz Marcus J , van Hooijdonk Roosmarijn TM , Kiyoshi Morita , Mackenzie Iain MJ , Annane Djillali , Stow Peter , Nasraway Stanley A , Holewinski Sharon , Holzinger Ulrike , Preiser Jean-Charles , Vincent Jean-Louis , Bellomo Rinaldo
Published: March 2013

Introduction

Hyperglycemia, hypoglycemia, and increased glycemic variability have each beenindependently associated with increased risk of mortality in critically illpatients. The role of diabetic status on modulating the relation of these threedomains of glycemic control with mortality remains uncertain. The purpose of thisinvestigation was to determine how diabetic status affects the relation ofhyperglycemia, hypoglycemia, and increased glycemic variability with the risk ofmortality in critically ill patients.

Methods

This is a retrospective analysis of prospectively collected data involving 44,964patients admitted to 23 intensive care units (ICUs) from nine countries, betweenFebruary 2001 and May 2012. We analyzed mean blood glucose concentration (BG),coefficient of variation (CV), and minimal BG and created multivariable models toanalyze their independent association with mortality. Patients were stratifiedaccording to the diagnosis of diabetes.

Results

Among patients without diabetes, mean BG bands between 80 and 140 mg/dl wereindependently associated with decreased risk of mortality, and mean BG bands> 140 mg/dl, with increased risk of mortality. Among patients withdiabetes, mean BG from 80 to 110 mg/dl was associated with increased risk ofmortality and mean BG from 110 to 180 mg/dl with decreased risk of mortality. Aneffect of center was noted on the relation between mean BG and mortality.Hypoglycemia, defined as minimum BG <70 mg/dl, was independently associatedwith increased risk of mortality among patients with and without diabetes andincreased glycemic variability, defined as CV > 20%, was independentlyassociated with increased risk of mortality only among patients without diabetes.Derangements of more than one domain of glycemic control had a cumulativeassociation with mortality, especially for patients without diabetes.

Conclusions

Although hyperglycemia, hypoglycemia, and increased glycemic variability is eachindependently associated with mortality in critically ill patients, diabeticstatus modulates these relations in clinically important ways. Our findingssuggest that patients with diabetes may benefit from higher glucose target rangesthan will those without diabetes. Additionally, hypoglycemia is independentlyassociated with increased risk of mortality regardless of the patient's diabeticstatus, and increased glycemic variability is independently associated withincreased risk of mortality among patients without diabetes.

See related commentary by Krinsley,http://ccforum.com/content/17/2/131

See related commentary by Finfer and Billot,http://ccforum.com/content/17/2/134
DriverNet: uncovering the impact of somatic driver mutations on transcriptional networks in cancer
Authors: Bashashati Ali , Haffari Gholamreza , Ding Jiarui , Ha Gavin , Lui Kenneth , Rosner Jamie , Huntsman David G , Caldas Carlos , Aparicio Samuel A , Shah Sohrab P
Published: March 2013

Simultaneous interrogation of tumor genomes and transcriptomes is underway in unprecedented global efforts. Yet, despite the essential need to separate driver mutations modulating gene expression networks from transcriptionally inert passenger mutations, robust computational methods to ascertain the impact of individual mutations on transcriptional networks are underdeveloped. We introduce a novel computational framework, DriverNet, to identify likely driver mutations by virtue of their effect on mRNA expression networks. Application to four cancer datasets reveals the prevalence of rare candidate driver mutations associated with disrupted transcriptional networks and a simultaneous modulation of oncogenic and metabolic networks, induced by copy number co-modification of adjacent oncogenic and metabolic drivers. DriverNet is available on Bioconductor or at http://compbio.bccrc.ca/software/drivernet/.
H. pylorivirulence factor CagA increases intestinal cell proliferation by Wnt pathway activation in a transgenic zebrafish model
Authors: Neal James T. , Peterson Tracy S. , Kent Michael L. , Guillemin Karen
Published: March 2013

Infection with Helicobacter pylori is a major risk factor for the development of gastric cancer, and infection with strains carrying the virulence factor CagA significantly increases this risk. To investigate the mechanisms by which CagA promotes carcinogenesis, we generated transgenic zebrafish expressing CagA ubiquitously or in the anterior intestine. Transgenic zebrafish expressing either the wild type or a phosphorylation-resistant form of CagA exhibited significantly increased rates of intestinal epithelial cell proliferation and showed significant upregulation of the Wnt target genes cyclinD1, axin2 and the zebrafish c-myc ortholog myca. Coexpression of CagA with a loss-of-function allele encoding the β-catenin destruction complex protein Axin1 resulted in a further increase in intestinal proliferation. Coexpression of CagA with a null allele of the key β-catenin transcriptional cofactor Tcf4 restored intestinal proliferation to wild-type levels. These results provide in vivo evidence of Wnt pathway activation by CagA downstream of or in parallel to the β-catenin destruction complex and upstream of Tcf4. Long-term transgenic expression of wild-type CagA, but not the phosphorylation-resistant form, resulted in significant hyperplasia of the adult intestinal epithelium. We further utilized this model to demonstrate that oncogenic cooperation between CagA and a loss-of-function allele of p53 is sufficient to induce high rates of intestinal small cell carcinoma and adenocarcinoma, establishing the utility of our transgenic zebrafish model in the study of CagA-associated gastrointestinal cancers.
Diamine Derivatives Accelerate Photochemical C → U Transition in DNA Double Strand
Authors: Fujimoto Kenzo , Futamura Daiki , Sakamoto Takashi
Published: March 2013

For the improvement of the deamination reaction of cytosine in the photocrosslinked DNA double strand, the effect of additives on the deamination reaction was evaluated. The results indicated that diamine derivatives can accelerate the reaction in a concentration-dependent manner. This provides a new design of artificial oligonucleotides having higher photoediting activities.
Hydration of Adamantane Skeleton: Water Assembling around Amantadine and Halo-substituted Adamantanes
Authors: Doi Hideo , Aida Misako
Published: March 2013

We performed Monte Carlo simulations to reveal the water distributions around adamantane derivatives. Adamantane derivatives attract water molecules, and specific water distributions are observed around the skeleton. Perfluoroadamantane attracts water more than adamantane.
Giant Vesicles Containing Microspheres with High Volume Fraction Prepared by Water-in-oil Emulsion Centrifugation
Authors: Natsume Yuno , Toyota Taro
Published: March 2013

We aimed to obtain giant vesicles (GVs) confining microspheres with a volume fraction of 20–30 vol %, analogous to biological macromolecules contained in cytosols, through simple and quick steps. Through water-in-oil (W/O) emulsion centrifugation, we formed GVs containing 1-µm polystyrene microspheres with volume fractions in the range 0–45 vol %.
Preparation of Palladium-loaded Polymer Nanoparticles with Catalytic Activity for Hydrogenation and Suzuki Coupling Reactions
Authors: Seto Hirokazu , Morii Takato , Yoneda Tamami , Murakami Tatsuya , Hoshino Yu , Miura Yoshiko
Published: March 2013

Palladium-loaded polymer nanoparticles with basic functional groups were prepared. When palladium ions were adsorbed on the polymer nanoparticles, the maximum loading capacity on the nanoparticles depended on the basic functional groups in the particles. The reduced palladium had a nanoscale average diameter. The palladium-loaded polymer nanoparticles exhibited catalytic activity for hydrogenation and Suzuki coupling reactions. The catalytic activity of the nanosized palladium-loaded nanoparticles was higher than that of bulk palladium.
Temperature-dependent Upconversion Luminescence of NaYF4:Yb3+,Er3+ Nanoparticles
Authors: Zhao Junwei , Li Haitao , Zeng Qinghui , Song Kai , Wang Xiaofeng , Kong Xianggui
Published: March 2013

The temperature-dependent quenching characteristics of the upconversion luminescence in NaYF4:Yb3+,Er3+ nanoparticles under 980-nm excitation are reported. Intense green and red upconversion emissions corresponding to the (2H11/2, 4S3/2) → 4I15/2 and 4F9/2 → 4I15/2 transitions of the Er3+ ions were observed. The green emission at around 520 nm presents a continuous increase with increasing temperature, while the emission bands at around 545 and 657 nm decrease with the temperature change from 84 to 364 K. The temperature dependence of the intensity characteristics was analyzed systematically by using a simple three-level system.
Bayesian Dynamic Pricing in Queueing Systems with Unknown Delay Cost Characteristics
Authors: Afèche Philipp , Ata Barış
Published: March 2013

The revenue management literature for queues typically assumes that providers know the distribution of customer demand attributes. We study an observable M/M/1 queue that serves an unknown proportion of patient and impatient customers. The provider has a Bernoulli prior on this proportion, corresponding to an optimistic or pessimistic scenario. For every queue length, she chooses a low or a high price, or turns customers away. Only the high price is informative. The optimal Bayesian price for a queue state is belief-dependent if the optimal policies for the underlying scenarios disagree at that queue state; in this case the policy has a belief-threshold structure. The optimal Bayesian pricing policy as a function of queue length has a zone (or, nested-threshold) structure. Moreover, the price convergence under the optimal Bayesian policy is sensitive to the system size, i.e., the maximum queue length. We identify two cases: prices converge (1) almost surely to the optimal prices in either scenario or (2) with positive probability to suboptimal prices. Only Case 2 is consistent with the typical incomplete learning outcome observed in the literature.
Predicting Purchase Timing, Product Choice, and Purchase Amount for a Firm's Adoption of a Radically Innovative Information Technology: An Analysis of Cloud Computing Services
Authors: Bohling Timothy R. , Kumar V. , Shah Riddhi
Published: March 2013

Cloud computing is a radically innovative information technology (IT) that has been widely commercialized, but understanding its adoption by a firm has been a mystery. Cloud computing offerings include servers, storage and data product services, and desktop cloud solutions for small businesses. Because prior knowledge about cloud computing adoption is quite limited, this paper attempts to fill the gap in the adoption–provider framework by identifying the drivers that help a firm adopt a radical innovation in a business-to-business scenario. We developed an integrated model that links the purchase timing, product choice, and purchase amount decisions of the different types of cloud computing services. The theory of relationship marketing consisting of “commitment” and “trust” constructs has been extended to include the “need” construct to explain the adoption behavior of the cloud computing services. We empirically tested the proposed framework using data from a large IT company. Results indicate that the proposed model predicts the purchase timing with an accuracy of 78%, type of choice with an accuracy of 81%, and purchase amount with a mean absolute percentage error of 28% for the cloud computing services. The paper highlights the contribution, limitations, and future research for both researchers and practitioners.
The Dark Side of Using Emergencies in Direct Marketing Campaigns for Blood Donation Services
Authors: Shehu Edlira , Langmaack Ann-Christin , Clement Michel
Published: March 2013

In this research paper, we investigate whether direct marketing campaigns that rely on emergencies are a successful strategy for nonprofit services. Prior literature grounded in monetary donations suggests that using direct marketing mailings with an emergency context should lead to a higher intention to donate blood than using mailings that are unrelated to emergencies. Contrary to this suggestion, we argue that mailings with an emergency context do not significantly increase the intention to donate beyond the effect from traditional standard invitation mailings with a rational appeal. To control for selection effects, we conducted a large experimental study (N = 1,054). We discover that in mailings of blood donation services, neither the use of emergencies nor the attribution of innocence to emergency victims leads to a significant increase in the intention to donate blood, for both former donors and nondonors, compared to a standard invitation mailing with a rational appeal to donate blood. We did not discover any interaction effect between the attribution of innocence to emergency victims and the drivers of donation behavior. However, the attribution of guilt to emergency victims shows a negative interaction effect on the extrinsic motive of social benefits for nondonors: the donation intention of nondonors driven by social benefits is significantly lower if they are addressed with mailings attributing guilt to the victims of emergencies. These results are highly relevant for the planning of direct marketing activities of nonprofit services.
Managing laboratory test ordering through test frequency filtering
Authors: Janssens Pim M.W. , Wasser Gerd
Published: March 2013

Background: Modern computer systems allow limits to be set on the periods allowed for repetitive testing. We investigated a computerised system for managing potentially overtly frequent laboratory testing, calculating the financial savings obtained.

Methods: In consultation with hospital physicians, tests were selected for which ‘spare periods’ (periods during which tests are barred) might be set to control repetitive testing. The tests were selected and spare periods determined based on known analyte variations in health and disease, variety of tissues or cells giving rise to analytes, clinical conditions and rate of change determining analyte levels, frequency with which doctors need information about the analytes and the logistical needs of the clinic.

Results: The operation and acceptance of the system was explored with 23 analytes. Frequency filtering was subsequently introduced for 44 tests, each with their own spare periods. The proportion of tests barred was 0.56%, the most frequent of these being for total cholesterol, uric acid and HDL-cholesterol. The financial savings were 0.33% of the costs of all testing, with HbA1c, HDL-cholesterol and vitamin B12 yielding the largest savings. Following the introduction of the system the number of barred tests ultimately decreased, suggesting accommodation by the test requestors.

Conclusions: Managing laboratory testing through computerised limits to prevent overtly frequent testing is feasible. The savings were relatively low, but sustaining the system takes little effort, giving little reason not to apply it. The findings will serve as a basis for improving the system and may guide others in introducing similar systems.
Native and Phosphorylated Bovine Adrenal Tyrosine 3-Monooxygenase. Interactions with Tetrahydropterins and Substrate and Stability of the Formed 4a-Hydroxy-Tetrahydrobiopterin
Authors: Haavik Jan , Andersson Kristoffer K. , Flatmark Torgeir , Petersson Leif
Published: March 2013

The catalytic activity of tyrosine 3-monooxygenase (tyrosine hydroxylase) is dependent on a tetrahydropterin cofactor and ezyme-bound iron. The oxidation of tetrahydrobiopterin by bovine adrenal tyrosine hydroxylase was studied by high performance liquid chromatography (HPLC). The first pterin product detected during catalytic turnover, 4a-hydroxy-tetrahydrobiopterin, was isolated by HPLC and the pseudo first-order rate constant of its dehydration to quinonoid dihydrobiopterin was estimated. The tl /2 was found to be 45 and 72 s in 100 and 5 mmol/L Tris-HCl, respectively, at pH 7.5 and 23 °C.

The rate of the 4a-hydroxy-tetrahydropterin formation was found to increase on phosphorylation of the enzyme by cyclic AMP-dependent protein kinase. The phosphorylation did not significantly change the electron paramagnetic resonance (EPR) spectrum of tyrosine hydroxylase. However, in the presence of substrate or cofactor and dithiothreitol, the EPR spectral properties were strikingly different from those observed prior to phosphorylation. Our findings are in accordance with a mechanism in which the covalently bound phosphate activates the enzyme by facilitating changes in the redox-state of the enzyme-bound iron.
Studies and Comparison of Urinary Pteridine Patterns in Dogs and Cats and their Alteration in Various Neoplasias and Virus Infections
Authors: Goldberg M. , Gassner F. , Merkenschlager M.
Published: March 2013

Urinary excretion levels of five pteridines in healthy cats and dogs and in 14 groups of animals with tumours or virus infections were determined by HPLC after partial purification by ion exchange chromatography. Healthy cats and dogs produce species specific differences. In contrary to cats 6-hydroxymethylpterin was not detectable in dogs. Whereas in dogs biopterin presents the main part of pteridines (about 70%), cats contain about 53% catabolic isoxanthopterin in the pteridine pattern. In the various tumours no qualitative but quantitative alterations in the pteridine concentrations could be detected. The changes in the different tumours were not applied to all pteridines, so that each type of tumour shows an own pattern of pteridines.

In the parvovirosis of the dog neopterin, biopterin and isoxanthopterin increased significantly. In the virusfree parvovirosis suspicious dogs only pterin was elevated. In the feline leucosis and feline infectious peritonitis a significant rise of all five measured pteridines were observed.

Altogether, the data show, that increased urinary pteridines present a real additional aid for the suspicion of neoplasias or viral infections in the veterinary medicine.
Quantitation of the Folate Binding Protein in Human Cerebrospinal Fluid by an Enzyme-linked Immunosorbent Assay (ELISA)
Authors: Ingemann Hansen Steen , Holm Jan , Høier-Madsen Mimi
Published: March 2013

An enzyme-linked immunosorbent assay (ELISA) was calibrated and used for quantitation of the folate binding protein in human cerebrospinal fluid. The precision of the assay in terms of the coefficient of variation was 6.3% intra-assay (10 replicate single determinations) and 4.8% inter-assay (8 duplicate determinations). The concentration of folate binding protein in cerebrospinal fluid specimens from 20 patients with no complaints or diseases of neurological type was 0.14-0.38, 0.24 nmol FBP/I (range and median value). The gelfiltration profiles of radioligand bound and immunoreactive folate binding protein were identical, both consisting of one major peak (M, '" 25000) and one minor peak (M, '" 1 00000).
Synthesis and In Vitro Biological Evaluation of β,γ-Methano Analogues of Methotrexate and Aminopterin
Authors: Rosowsky Andre , Forsch Ronald A. , Moran Richard G. , Freisheim James H.
Published: March 2013

β,γ-Methano derivatives of methotrexate (MTX) and aminopterin (AMT) were synthesized with the aim of assessing the effect of this side-chain modification on dihydrofolate reductase (OHFR) inhibition, folylpolyglutamate synthetase (FPGS) inhibition, and tumor cell growth inhibition. Mixed carboxylic-carbonic anhydride (MCA) coupling of 4-amino-4-deoxy-N10-methylpteroic acid (mAPA) and dimethyl trans-α-(2-carboxycyclopropyl) glycinate, followed by alkaline hydrolysis, afforded N-( 4-amino-4-deoxy-N10-methylpteroyl)-α-( trans-2-carboxycyclopropyl)glycine (β,γ-methanoMTX) as a mixture of the four possible diastereomers with trans substitution on the cyclopropane ring. N-(4-Amino-4-deoxypteroyl)-trans-α.-(2-carboxycyclopropyl) glycine (β,γ-methanoAMT) , also as a diastereomer mixture, was obtained from 4-amino-4-deoxy-N10 - formylpteroic acid (fAPA) and dimethyl trans-α-(2-carboxycyclopropyl)-glycinate by MCA coupling and alkaline hydrolysis of the ester and N10-formyl groups. β,γ-MethanoMTX and β,γ-methanoAMT may be viewed as MTX and AMT analogues with a conformationally restricted side chain. In vitro biological activity data for these novel compounds support the view that the active site of DHFR, already known for its ability to tolerate modification of the γ-carboxyl group of MTX and AMT, can likewise accommodate substitution on the β- and γ-carbons.
An Enzyme Immunoassay for Neopterin and Biopterin Using a Microtitre Plate Linked with N2-(3-Aminopropyl) Derivatives of Pteridines
Authors: Sugimoto Takashi , Ogiwara Shoji , Kiuchi Kazutoshi , Nagatsu Toshiharu , Sakai Masao , Nagatsu Ikuko , Fujita Keisuke
Published: March 2013

A novel and sensitive enzyme immunoassay for neopterin and biopterin using a microtitre plate has been developed. The antiserum against neopterin or biopterin was incubated with samples prepared from human urine or rat tissues, and was placed in a well of microtitre plate, where N2-(3-aminopropyl) derivative of neopterin or biopterin was kinked by poly-L-Iysine and glutaraldehyde. The antibody, which did not form the immunocomplex with the hapten in the sample, was bound to the fixed hapten on the plate, and then was measured with anti rabbit IgG and peroxidase anti-peroxidase complex. The detection limits of these pterins were both 0.1 pmol. The specificity of the assay was so high that this assay system with employing anti-neopterin antiserum completely distinguished neopterin from biopterin, as judged from the cross reactivity (0.002%) and vice versa. The amounts of neopterin and biopterin in human urine and rat tissues measured by the present assay showed a good agreement with those determined by high performance liquid chromatography.
Enzymatic Synthesis of Four Stereoisomers of 7-0xo-biopterin and Determination of the Absolute Structure of Ichthyopterin
Authors: Takikawa Shin Ichiro , Matsuura Sadao
Published: March 2013

Enzymatic conversion of stereoisomers of biopterin (3a-d) to the 7-oxo-biopterin isomers (4a-d) was performed with a new pterin 7-oxidase extracted from carp skin. The chiral centers of the 6-side chains of biopterin isomers were preserved during the conversion, and the four possible stereoisomers of 7-oxo-biopterin (4a-d) were obtained from the corresponding biopterin isomers (3a-d). HPLC and CD spectra studies showed that natural ichthyopterin is 2-amino-6-(L-erythro-1',2' -dihydroxypropyl)-4, 7(3H,8H)-pteridinedione (4a) which has the same L-erythro structure at the side chain as natural biopterin (3a). This fact suggests that ichthyopterin is biologically derived from biopterin in these fishes.
Solvent Effects upon the Electronic Absorption and Fluorescence Spectra of Pteridines and Riboflavin and Their Ground and First Excited Singlet State Dipole Moments
Authors: Aaron J.-J. , Gaye M. D. , Párkányi C. , Boniface C. , Bieze T. W. N , Atik S. S. , Raghu Veer K. S. , Szentpály L. von , Ghosh R.
Published: March 2013

The electronic absorption. fluorescence excitation, and fluorescence emission spectra of a series of pteridines (lumazine, xanthopterin, isoxanthopterin, biopterin) and riboflavin (vitamin B2) were measured at room temperature (298 K) in a number of solvents covering a wide range of polarities (dioxane, ethyl ether, chloroform, ethyl acetate, 1-butanol. 2-propanol, ethanol, methanol, dimethylformamide, acetonitrile, and dimethyl sulfoxide). The effects of the solvent upon the spectral properties are discussed. Experimental groundstate dipole moments were measured for selected compounds and were used in combination with the spectral data to evaluate their first excited singlet-state dipole moments by means of the solvatochromic shift method (Bakhshiev's and Kawski-Chamma-Viallet's equations based on the variation of the Stokes shift with the solvent dielectric constant-refractive index term). The theoretical ground and excited singlet-state dipole moments for all pteridines and riboflavin were calculated as a vector sum of the π-component (obtained by the PPP method) and the a-component (obtained from a-bond moments). A second set of theoretical values was obtained by using the CNDO/2method. A good agreement was observed between the experimental and the theoretical values. Excited singlet-state dipole moments are higher than the ground state values by 1 to 6 Debye units for all the pteridines under study with the exception of xanthopterin.
Tetrahydrobiopterin Deficiency: From Phenotype to Genotype
Authors: Blau Nenad , Thöny Beat , Heizmann Claus W. , Dhondt Jean-Louis
Published: March 2013

As a result of the selective screening worldwide during the last 18 years, approximately 250 patients with tetrahydrobiopterin deficiency were discovered. Most patients suffer from 6-pyruvoyl tetrahydropterin synthase deficiency (58%), followed by dihydropteridine reductase deficiency (35%), GTP cyclohydrolase I deficiency (3%), and “primapterinuria” (4%). The patients can be treated with neurotransmitter precursors, as well as with tetrahydrobiopterin. However, data on long term treatment are still scarce and it is therefore of great value to investigate all newborns with even mild hyperphenylalaninemia. Cloning of the enzymes involved in the biosynthesis and regeneration of tetrahydrobiopterin makes them to be easily accessible for biochemical and biological studies. So far, all proteins expressed heterologous are active in E. coli. Cloning of the wild type gene and mutant analysis of patients allow the rapid identification of the defective gene on the molecular level.
Pteridines XCVIII. Synthesis and Properties of 1-Methylpterins
Authors: Pfleiderer Wolfgang
Published: March 2013

A series of 1-methyl-pterin derivatives (6-13) have been synthesized by condensation and methylation reactions. The compounds have been characterized by elemental analyses, pKa deterimations and UV spectra. Comparisons of the physical data of the corresponding N-1 and N-3 methyl-pterins indicate why the normal pterins exist in aqueous solution preferentially in the N3-H tautomeric configuration. The thermodynamical stability of the lactam group forces the acidic H-atom to adapt the nitrogen adjacent to the carhonyl function but no other vinylogous position. A lactam group does not participate in heteroaromatic cyclic resonance, in general.
Theoretical Stereostructure of the Neutral Form of Natural Tetrahydrobiopterin
Authors: Katoh Setsuko , Sueoka Terumi , Kurihara Teruo
Published: March 2013

The absolute conformation and the reactivity of atoms of the neutral form of natural tetrahydrobiopterin [(6R)-6-(L-erythro-1 ′,2′ -dihydroxypropyl)-5.6.7.8-tetrahydropterin] was determined by the Molecular-Orbital method within the MINDO/3 framework. Two different conformations (Form A and Form B) of the alkyl side chain relative to the pterin ring were obtained as the optimized form for the lowest energy conformation (ΔH= -174 kcal/lmol) of this molecular constitution with the same molecular width of 11.2 Å. Form A and B were distinguishable in the dihedral [01′ -C1′ -C6-H6J of - 88° and 30°. respectively. Net charges of atoms of Form A and B suggested that the predominant reactivity of the atoms of N1 C2. C4. O4, C4a. and C8a of the pterin ring and C1′. C2′. O1′ and O2′ of the side chain. It was also suggested that the position 2' is more active than the position 1′. in the alkyl side chain of Form A and B. toward NADP+ in the reverse reaction of sepiapterin reductase.
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

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

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.
Synthesis of 6β-N(5)-Methyl-5,6,7,8-tetrahydro-L-biopterin
Authors: Bosshard Rene , Heizmann Claus W. , Viscontini Max
Published: March 2013

Summary 6β-N(5)-methyl-5.6J,8-tetrahydro-L-biopterin·2 HC1. a new derivate of biological interest, was synthesized from 6β-5,6,7,8-tetrahydro-L-biopteril·2 HC1 and characterized. The latter compound has been used therapeutically in atypical phenylketonuria for many years. The catalytic reductive methylation with PtO2 /H2 and formaldehyde allowed selective methylation at the N(5) position. The chemical properties and stnlctures of the new compound arc compared with N(5)-methyl-tetrahydropterin and N(5)-methyl-tetrahydrofolate.
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

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

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

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

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

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

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.