bluuebunny/crossref_metadata_2025 huggingface dataset:
Rotational diffusion of particles in turbulence
Authors: Meyer Colin R. , Byron Margaret L. , Variano Evan A.
Published: August 2013

Lay Abstract

In aquatic environments, particles (e.g., sediment or microorganisms) tend to rotate as they move. For example, rotation is an important component of a microorganism's motion and search for food. Using two simple shapes, a sphere and a prolate ellipsoid (i.e., a football), we examined how shape affects rotation. To isolate the effects of rotation from the effects of settling, we made near neutrally buoyant particles (same density as water). We generated turbulence in a laboratory water tank and introduced hundreds of particles, one shape at a time. While the particles were tumbling in the flow, we measured their rotation by using stereoscopic particle image velocimetry (SPIV), a technique that uses a laser to light up tracers embedded in the particles and then takes photos in rapid succession to compute the point velocities inside the particle. Since every part of the body rotates at the same angular speed, we determined all components of the angular velocity from the velocities inside the particles. A series of SPIV images showed how rotation of the particle changes over time in the turbulence. Using the average of many different sets of images, we modeled the change in particle rotation over time as a random walk through the range of possible rotations. We found that ellipsoidal and spherical particles rotated with the same characteristic time, unaffected by shape difference. From this we concluded that the large scales of turbulence govern rotation, rather than the small scales; large eddies, which are unable to differentiate between spheres and ellipsoids, determine rotation.
Superphenalenyl: Theoretical Design of a π-Conjugated Planar Hydrocarbon Radical
Authors: Ikabata Yasuhiro , Akiba Kin-ya , Nakai Hiromi
Published: August 2013

We propose “superphenalenyl” as a novel π-conjugated planar hydrocarbon radical. Theoretical calculation was performed to evaluate its stability compared to phenalenyl and trioxotriangulene. The result of spin distribution and reaction energy supports its high stability. Molecular properties of this radical are also discussed based on orbital energies.
Strong anion-exchange fast performance liquid chromatography as a versatile tool for preparation and purification of RNA produced by in vitro transcription
Authors: Koubek Jiri , Lin Ku Feng , Chen Yet Ran , Cheng Richard Ping , Huang Joseph Jen Tse
Published: August 2013

Here we demonstrate the use of strong anion-exchange fast performance liquid chromatography (FPLC) as a simple, fast, and robust method for RNA production by in vitro transcription. With this technique, we have purified different transcription templates from unreacted reagents in large quantities. The same buffer system could be used to readily remove nuclease contamination from the overexpressed pyrophosphatase, the important reagent for in vitro transcription. In addition, the method can be used to monitor in vitro transcription reactions to enable facile optimization of reaction conditions, and we have compared the separation performance between strong and weak anion-exchange FPLC for various transcribed RNAs, including the Diels-Alder ribozyme, the hammerhead ribozyme tRNA, and 4.5S RNA. The functionality of the purified tRNACys has been confirmed by the aminoacylation assay. Only the purification by strong anion-exchange FPLC has led to the enrichment of the functional tRNA from run-off transcripts as revealed by both enzymatic and electrophoretic analysis.
The rat model of femur fracture for bone and mineral research
Authors: Aurégan J-C. , Coyle R. M. , Danoff J. R. , Burky R. E. , Akelina Y. , Rosenwasser M. P.
Published: August 2013

Objectives

One commonly used rat fracture model for bone and mineral research is a closed mid-shaft femur fracture as described by Bonnarens in 1984. Initially, this model was believed to create very reproducible fractures. However, there have been frequent reports of comminution and varying rates of complication. Given the importance of precise anticipation of those characteristics in laboratory research, we aimed to precisely estimate the rate of comminution, its importance and its effect on the amount of soft callus created. Furthermore, we aimed to precisely report the rate of complications such as death and infection.

Methods

We tested a rat model of femoral fracture on 84 rats based on Bonnarens’ original description. We used a proximal approach with trochanterotomy to insert the pin, a drop tower to create the fracture and a high-resolution fluoroscopic imager to detect the comminution. We weighed the soft callus on day seven and compared the soft callus parameters with the comminution status.

Results

The mean operating time was 34.8 minutes (sd 9.8). The fracture was usable (transverse, mid-shaft, without significant comminution and with displacement < 1 mm) in 74 animals (88%). Of these 74 usable fractures, slight comminution was detected in 47 (63%). In 50 animals who underwent callus manipulation, slight comminution (n = 32) was statistically correlated to the amount of early callus created (r = 0.35, p = 0.015). Two complications occurred: one death and one deep infection.

Conclusions

We propose an accurate description of comminution and complications in order to improve experiments on rat femur fracture model in the field of laboratory research. Cite this article: Bone Joint Res 2013;2:149–54.
Sialylexoenitols as precursors for new analogues of sialidase inhibitors
Authors: Richichi Barbara , Lunghi Carlotta , Papakyriakou Athanasios , Francesconi Oscar , Nativi Cristina
Published: August 2013

Sialic acids are involved in a plethora of important biological events; among these the most known certainly is the binding of N-acetylneuraminic acid (Neu5Ac) with influenza virus sialidase. Considering Neu5Ac as the template that led to the structure-based development of the two potent antiviral agents zanamivir and oseltamivir, we developed the synthesis of the sialylexoenitol, a new class of sialyl derivative that was used as precursor in powerful hetero-Diels–Alder reactions to form the corresponding spiroketals. Docking calculations employing the crystallographic structure of influenza virus sialidase indicate that these scaffolds could probably interact with most of the active site residues that stabilize Neu5Ac. In addition, their reduced polar nature with respect to Neu5Ac derivatives might provide inhibitors with increased bioavailability.
Evaluation of the N Latex free light chain assay in the diagnosis and monitoring of AL amyloidosis
Authors: Mollee Peter , Tate Jill , Pretorius Carel J.
Published: August 2013

Background: We compared a novel assay for free light chain (FLC) quantitation based on monoclonal antibodies (N-Latex, Siemens, Germany) to the established polyclonal antibody-based assay (Freelite™, The Binding Site, UK) in AL amyloidosis.

Methods: Sixty-two diagnostic samples were analysed on a BNII nephelometer, 32 of which also had a post-treatment sample.

Results: In the diagnostic samples: for AL of κ type, the median involved FLC (iFLC) was significantly lower by the N-Latex assay (289 vs. 667 mg/L, p=0.0002) whereas for λ AL the values were similar (148 vs. 161 mg/L, p=0.84). Measurable disease, defined as a difference between involved and uninvolved FLC (dFLC) >50 mg/L was present in 82% by the N-Latex assay compared to 89% by the Freelite™ assay. For diagnostic sensitivity, the FLC ratio was normal in 21% (95% CI 12%–33%) and 15% (95% CI 7%–26%) of patients by the N-Latex and Freelite™ assays, respectively. The combination of serum and urine immunofixation electrophoresis with either FLC assay allowed identification of the amyloidogenic clone in 98% producing comparable sensitivity. For the monitoring samples the median reduction in dFLC was 68% for the N-Latex assay and 77% for the Freelite™ assay (p=0.04). This led to some differences in assigning response categories. Partial response as assigned by both assays predicted overall survival (N-Latex p=0.0015, Freelite™ p=0.022).

Conclusions: There are differences between FLC as measured by the N-Latex and Freelite™ assays, but overall the two assays have similar diagnostic sensitivity. Disease response calculated by both assays predicts survival but more clinical validation is required.
Urinary Neopterin Indicates Early Infection and Disease Progression: Model Studies with Simian and Human Immunodeficiency Viruses in Macaques
Authors: Stahl-Hennig Christiane , Fendrich Claudia , Lüke Wolfgang , Widner Bernhard , Hunsmann Gerhard , Fuchs Dietmar
Published: August 2013

The value of urinary neopterin as a predictive marker for disease progression in SIV- and HIV-2-infected rhesus (Macaca mulatta) and cynomolgus macaques (Macaca fascicularis) was assessed by comparing pre- with postinfection data. Before infection stable baselines for neopterin were observed in both species with significantly higher concentrations in cynomolgus macaques than in rhesus macaques. After infection of cynomolgus macaques with human immunodeficiency virus type 2 (HIV-2) neopterin concentrations exceeded 1.2 - 4.2 times preinfection values, whereas rhesus monkeys infected with simian immunodeficiency virus (SIV) yielded concentrations of more than 8 times above baseline. Increased neopterin concentrations always preceded seroconversion. No rise of neopterin was observed in cynomolgus macaques remaining seronegative after inoculation with HIV-2, whereas after inoculation with SIV neopterin was slightly elevated in rhesus monkeys despite remaining seronegative. In animals with high virus replication a pronounced increase of neopterin levels was followed by signs of immunodeficiency. Therefore like in HIV-1-infected man, in macaques infected with SIV or HIV-2 the urinary neopterin concentration is an early and reliably predictive marker for AIDS disease progression and reflects pathogenicity. This parameter can be easily assessed in study protocols for drug and vaccine tests in monkeys as in man.
Neopterin, IgG, IgA, IgM, and Plasma Volume Changes During Long-distance Running
Authors: Gunga Hanns-Christian , Machotta Andreas , Schobersberger Wolfgang , Mittermayr Markus , Kirsch Karl , Koralewski Eberhard , Röcker Lothar
Published: August 2013

Prolonged physical exercise is associated with several immunological changes, e.g. increase in proinflammatory cytokines, changes in the white blood count etc. Great discrepancies exist with regard to the exercise- induced influence on serum immunoglobulin and neopterin values. One explanation could be the shifts in plasma volume (PV) during and after exercise which might influence plasma concentrations of these parameters. Therefore we investigated the consequences of a marathon race in a homogenous group of experienced runners on plasma volume shifts, serum Immunglobulin and neopterin concentrations. Plasma values with and without correction for plasma volume shifts were compared. PV was significantly diminished after the race (-8.4%) followed by a rise 34h after finish (+8.5%). Serum immunoglobulin IgG, IgA and IgM were increased within the first hours postmarathon and normalized in the recovery period. When chages in PV were considered, only IgA rose significantly. Serum neopterin remained unchanged after the marathon independently whether corrected for PV changes or not. We conclude that the increase in immunoglobulins in our study was mainly the consequence of plasma volume changes. Since neopterin was unchanged we have at least in our study no evidence for exercise-induced activation of the cellular immune system.
Immunologic Alterations in Schizophrenia: Neopterin, L-Kynurenine, Tryptophan and T-Cell Subsets in the Acute Stage of Illness
Authors: Sperner-Unterweger Barbara , Miller Carl , Holzner Bernhard , Laich Andreas , Widner Bernhard , Fleischhacker Wolfgang W. , Fuchs Dietmar
Published: August 2013

It is well established now that in diseases with activated cell-mediated immunity increased formation of neopterin and degradation of tryptophan is an indication of endogenous production of interferon-γ in patients. Therefore increased neopterin levels are associated with increased kynuremne levels and decreased tryptophan in patients suffering from virus infections, malignant diseases or autoimmunity. To investigate cell-mediated immunity m schizophrenia, neopterin, L-kynurenine, L-tryptophan and T-cell-subsets were measured in 10 chronic schizophrenic patients, addmitted to hospital due to acute psychiatric relapse. Low neopterin concentrations were found at the beginning of hospitalisation and followed by a significant increase at the time of discharge (p = 0.02). Mean neopterin values were still within the 95th percentile of healthy controls. Kynuremne levels showed a similar development (p = 0.03) as neopterin whereas tryptophan values were low at admission without any significant changes thereafter. CD3 + and CD4+-cells presented with highest numbers at admission, followed by a continuous decrease and NK-cells were found lowest on day 0 with a gradual increase by day 7. These findings argue against acute virus infection in acutely ill schizophrenic patients because this would be associated with incerased neopterin fromation and tryptophan dagradation, rather the data would be in line with a shift from TH-1 to TH-2-type immune reaction which which is common in chronic infections.
A New Functional Role of 5,6,7,8-tetrahydrobiopterin (BH4) as an Inhibitor of γ-glutamylcysteine Synthetase (γ-GCS) mRNA Expression
Authors: Kojima Shuji , Kurozumi Risa , Tuchiya Maiko
Published: August 2013

The effect of the intracellular 5,6,7,8-tetrahydrobiopterin (BH4) on the increased γ-glutamylcysteine synthetase (γ-GCS) mRNA expression induced by nitric oxide (NO) was investigated in RAW264.7 cells. Low doses of nitroprusside (SNP), ranging from 0.1 mM to 0.5 mM, significantly increased the intracellular glutathione levels along with the expression of mRNA for γ-GCS, a rate limiting enzyme of de novo glutathione synthesis. The increased expression was not abolished by exogenously added BH4 itself, but by sepiapterin, a precursor of BH4 synthesis, in a dose-dependent manner. The blockage by sepiapterin was ineffective in the presence of N-acetyl serotonin (NAS), an inhibitor of sepiapterin reductase. The increased γ-GCS mRNA expression was also inhibited by catalase, a scavenger of hydrogen peroxide. Evidence was further provided that BH4 effectively scavenged hydrogen peroxide. These results suggest that intracellular BH4 may play a role as an inhibitor of glutathione synthesis induced by NO via scavenging hydrogen peroxide, a mediator of the gene expression for the de novo glutathione synthesis pathway.
Differential Inhibition of Constitutive and Inducible Nitric Oxide Synthase in Vascular Endothelial Cells by Analogues of Tetrahydrobiopterin
Authors: Mueller Nicolas J , Walter Roland Β , Linscheid Philippe , Schaffner Andreas , Schoedon Gabriele
Published: August 2013

In the vasculature, a physiologic production of nitric oxide (NO) is maintained by endothelial nitric oxide synthase (eNOS). Induction of inducible nitric oxide synthase (ÍNOS) under inflammatory conditions (e.g. septic shock) resulting in high levels of nitric oxide (NO) is believed to be partly responsible for the pathophysiologic changes in the vascular system that occur under inflammatory conditions (e.g. septic shock). Both NOS isoforms are dependent on the obligatory cofactor tetrahydrobiopterin (BH4). We investigated the selectivity and potency of the BH4 analogues 4-amino-BH4 and 5-methyl-BH4 in inhibiting eNOS and iNOS in a murine vascular endothelial cell (MVEC) model expressing either eNOS or iNOS under physiologic and inflammatory conditions, respectively. Exogenous BH4 and its precursor sepiapterin both enhanced physiologic eNOS activity in resting MVEC, while 4-amino-BH4 slightly inhibited eNOS. 5-methyl-BH4 did not have any effect on eNOS. BH4, sepi - apterin, and 5-methyi-BH4 had no effect on iNOS in inflammatory activated MVEC. In contrast, 4-amino-BH4 selectively inhibited iNOS with a potency comparable to the unselective NOS inhibitor Νω-monomethyl-L-argimne (L-NMMA). The present study demonstrates that 4-amino-BH4 selectively and potently inhibits iNOS in vascular endothelial cells, while its effect on eNOS is minimal. The selective inhibition of iNOS is a promising strategy for the treatment of inflammatory conditions with high output of NO. Further in vivo studies are required to determine whether inhibition of NO production by analogues of BH4 offers any advantage compared to inhibition by L-arginine analogues.
Tryptophan Metabolites as Scavengers of Reactive Oxygen and Chlorine Species
Authors: Weiss Günter , Diez-Ruiz Antonio , Murr Christian , Theur Igor , Fuchs Dietmar
Published: August 2013

Upon stimulation with interferon-γ, a typical Thl cell-derived cytokine, human monocyte-dertved macrophages produce neopterin derivatives and in parallel degrade the essential amino acid L-tryptophan to L-kynurenine and subsequently to 3-hydroxyanthramlic acid and anthramlic acid. In parallel, stimulated macrophages produce reactive oxygen species such as hydrogen peroxide and hypochlorous acid. Earlier, neopterin and 7.8-dihydroneoptenn were found to enhance or decrease effects of reactive oxygen species in vitro, depending on concentration and on environmental condition. In this study, we investigated the ability of tryptophan and its metabolites to interfere with radicals in vitro by means of a chemiluminiseence-based assay system. When using hydrogen peroxide or chloramine Τ as source for radical formation. L-tryptophan and its catabolites reduced chennluminescence according to a dose-response relationship, 3-hydroxvanthranilic acid being the most efficient compound. Apart from L-kynurenme the scavenging effects of tryptophan and its metabolites were not affected by changes m pH from 5.5 to 7.5. Our data indicate that tryptophan degradation produces metabolites with a high scavenging ability for reactive oxygen and chlorine species, thereby establishing a self-regulatory mechanism to limit the tissue damage by reactive radicals produced by macrophages.
Urinary Neopterin Concentrations in Healthy Individuals with Household Contact
Authors: Winkler Christiana , Wirleitner Barbara , Werner Ernst R. , Fuchs Dietmar
Published: August 2013

Increased neopterin concentrations in serum and urine indicate activation of cell-mediated immunity. In this study, urinary neopterin concentrations of a family consisting of 1 child (aged 5 years), her parents, and her grandparents were determined over a one year period and the course of neopterin levels was compared. Urine specimens were taken every second week during 1 year beginning in June. All 5 individuals lived in the same house, child and her parents separated by one floor from the grandparents. Neopterin concentrations were determined by high Performance liquid chromatography. In adults, neopterin concentrations were very stable throughout the year and peak increases occurred only rarely. In contrast, 5 sharp peaks of urinary neopterin concentrations were observed in the child, all occurring during the period when she was attending the kindergarten. Comparing the course of neopterin concentrations between the persons tested, several corresponding elevations of urinary neopterin were detected in the child and her relatives. The best association was detected between the child and her father (3 peaks of neopterin concentrations were observed, 1 of which coinciding with a peak in the child and two peaks with two weeks delay in the father). Between the child and her mother 1 corresponding neopterin peak was observed. One highly increased urinary neopterin concentration was observed in the grandmother which corresponded to a peak in the child with two weeks delay, a similar Observation was made between the child and her grandfather. In summary, high degree of correspondence in neopterin peaks was detected between child and adults. The data render it likely that the child was transmitting infectious diseases which she acquired at the kindergarten to her relatives, and the data are in line with the assumption that a dose family contact between individuals increases the risk of infectious disease transmission via household contact.
Neopterin Profile to Evaluate the Effectiveness of Treatment in Aggressive Periodontitis
Authors: Bodur Aysen , Baydar Terken , Ozmeric Nurdan , Engin Ayse Basak , Uraz Ahu , Eren Kaya , Sahin Gonul
Published: August 2013

Periodontal disease results from the interaction of the host defence mechanisms with the microbial dental plaque. Analysis of gingival crevicular Huid (GCF) provides a non-invasive means of evaluating the role of the host response in periodontal disease. Based on our previous study, demonstrating increased levels of neopterin in GCF and saliva from patients with aggressive periodontitis (AgP), the aim of this study was to evaluate the effect of periodontal treatment on the levels of neopterin in GCF, saliva and urine of patients with AgP.

Pre-treatment values of neopterin in GCF were 4.04 ± 0.86 nmol/ml for the AgP group (n=8) and 2.68 ± 0.90 nmol/ml fyr the control group (n=8; difference not significant). After periodontal treatment, the level of ncoptei in was found 2.38 ± 0.72 nmol/ml in the patient group which did not differ f r om pre-treatment levels. The salivary neopterin concentration was higher in both AgP groups (14.14 ± 2.85 nmol/1 and 8.02 ± 3.12 nmol/1, before and after periodontal treatment) than in controls (2.58 ± 0.3 nmol/1; both p<0.05). No significant difference in salivary neopterin level was observed in patients before and after periodontal treatment.

Concentrations of urine neopterin in patients before treatment were 188.5 ± 30.98 μηιοί neopterin/mol creatinine and 168.1 + 20.21 μηιοί in controls (difference not significant). Following periodontal treatment, the urinary neopterin levels (310.1 ± 39.82 μηιοί neopterin/mol creatinine) were higher when compared to the baseline levels and to controls (p<0.05).

Our results suggest that neopterin in saliva and GCF might be associated with the periodontal diseases process.
On the Mechanisms of the Neopterin-induced Suppression of Renal Erythropoietin Production
Authors: Pagel Horst , Hoffmann Georg , Fuchs Dietmar , Schobersberger Wolfgang
Published: August 2013

Earlier neopterin was demonstrated to inhibit hypoxia-induced erythropoietin synthesis in isolated perfused rat kidneys. The present experiments were performed to gain further insight into the mode of action underlying this effect. Numerous studies provided evidence of a link between neopterin and oxidative stress as well as intraccllular calcium concentrations. Thus, neopterin (200 μM) NQS added into the perfusion medium together with either the caclium Channel blocker Verapamil (5 μM) or the anti-oxidant N-acetylcysteine (200 μM). The addition of neopterin as a Single stimulus resulted in a significant decrease in the rate of hypoxia-induced eryihropoietin release accompanied by an augmented renal vascular resistance and a reduced perfusion flow rate. Although these data point towards an involvement of calcium and/or reactive oxygen species, verapamil or Nacetyleysteine were able to abrogate the suppression of erythropoietin generation which was induced by neopterin. Therefore, the mechanisms responsible for the impact of neopterin on the production of this growih lactor in the kidney remain to be elucidated.
Clinical Application of Cerebrospinal Fluid Neopterin Concentrations in HIV Infection
Authors: Hagberg Lars , Andersson Lars-Magnus , Abdulle Sahra , Gisslén Magnus
Published: August 2013

HIV-1 infects the central nervous system (CNS) and may cause AIDS dementia complex (ADC) and other neurologic complications. The cerebrospinal fluid (CSF) virus load is usually 0,5 -1 log lower than in blood, but in some patients the CSF quantitative HIV-1 RNA values exceed the paired blood samples. CSF neopterin concentrations are increased in all stages of HIV-1 infection, with the highest concentrations in AIDS patients and patients with CNS opportunistic infections. CD4 cell count and quantitative HIV RNA PCR tests in peripheral blood are used in clinical practice to monitor the HIV-1 infection and the anti-retroviral treatment effect. In most patients the anti-retroviral treatment response is similar in the cerebrospinal fluid (CSF) compare to the peripheral blood and the CSF viral load and neopterin concentrations are markedly reduced following treatment. ADC has become a rare complication. In spite of virological effective treatment many patients have a low grade intrathecal immunoactivation, measured as CSF neopterin concentrations above the 95% confidence interval found in IIIV-1 negative controls, after such a long time as after 2 years of anti-retroviral treatment.

The risk of long term intrathecal immunoactivation and which anti-retroviral combination treatment has the best effect on CSF parameters is not known. CSF neopterin concentrations are at present not used in clinical practice but may add valuable information.
Linkage of Pteridine Metabolism to Iron Homeostasis
Authors: Weiss Günter
Published: August 2013

Iron is an essential growth factor for the proliferation and differentiation of all living cells in being centrally involved in oxygen transport by hemoglobin and myoglobin, in electron transport during mitochondrial respiration as being a part of complex I and II enzymes or in the regulation of transcription via its role as central component of ribonucelotid reductase (1,2). Moroever, iron plays a critical role in macrophage mediated cytotoxicity by contributing to the production of highly toxic hydroxy radical species needed for host defense (3). In addition, radicals formed by the catalytic action of by iron can modulate the binding affinities of several transcription factors to their target promoter region, such as hypoxia inducible factor -1 or nuclear factor-kB, thus affecting transcription of stress inducible genes (4-6).
Interferon-y-Induced Growth Inhibition of Neuroblastoma Cells is Independent of Induction of Nitric Oxide Synthase and Indoleamine 2,3-dioxygenase
Authors: Leitner Stephan , Golderer Georg , Winkler Christiana , Fuchs Dietmar , Werner-Felmayer Gabriele , Werner Ernst R.
Published: August 2013

We investigated a possible involvement of nitric oxide formed by inducible nitric oxide synthase (iNOS) in the signaling cascade leading to growth inhibition and differentiation in the human neuroblastoma cell line SK-NSII. Treatment of SK-N-SH with interferon-γ (IFN-γ) plus interleukin-lß (IL-lß) led to induction of iNOS, growth inhibition and an altered cell shape. However two inhibitors of iNOS were not able to prevent cytokine induced changes. In addition, IFN-γ alone led to growth inhibition in absence of iNOS induction. Inhibition of the induced indoleamine 2,3-dioxygenase (IDO) activity also did not prevent growth inhibition. Our findings show that mechanisms other than NO and IDO can control interferon-y-induced growth inhibition of SK-N-SH cells.
Modulation of Free Radical Formation by Pterin Derivatives
Authors: Karl Oettl , Greilberger Joachim , Reibnegger Gilbert
Published: August 2013

All classes of pterins, fully reduced tetrahydropterins, aromatic pterins and dihydropterins have been investigated upon their effects on radical mediated reactions. Meanwhile all these classes were shown to act as both, proand antioxidants by a number of different methods including chemical, biochemical and biological systems. From reduced pterins radicals including oxygen-, nitrogen- and pterin-radicals arc formed enzymatically and non-enzymatically, reduced pterins react with free radicals and serve as reductive agents. All classes of pterins may interfere with enzymes involved in radical formation. Upon the diversity of possibilities the net effect of a particular compound is a question of the experimental settings and the physiological relevant role often remains obscure.
Modulation of Folate Dependent DNA Methyltransferase 1 (dnmt1) Activity in Whole Body γ-irradiated Mice.
Authors: Batra Vipen , Kesavan Vellapan , Mishra Kaushal P.
Published: August 2013

The methylation pattern of DNA is established during embryogenesis and is subsequently maintained by maintenance methylation activity of the enzyme DNA methyltransferase 1 (dnmtl). The modulation of nuclear dnmtl activity in nuclear and post-nuclear supernatant fractions was studied after various time intervals in 1, 3. 5 and 7 Gy whole body γ-irradiated mice. Significant changes in enzyme activity were observed in nuclear fraction of liver at various stages after irradiation. Our results show a dose-dependent increase in nuclear dnmtl activity after 24 hours al 1 to 5 Gy, with the maximum increase in activity at 7 Gy. An attenuation of enzyme activity was observed after 48 hours, which was continued at 96 hours post-iradiation, where the activity approached subnormal levels at higher doses. The dnmtl activity was less conspicuous in supernatant fraction and no significant change in activity was observed 24 hours after irradiation. Present studies suggest the possible role of radiation as a stressor in modulating the folate dependent dnmtl activity, which in turn may affect global DNA methylation pattern.
Increased Neopterin Concentration in Older Age Coincides with Decline of CD28+CD45RA+ T-cells
Authors: Murr Christian , Hainz Ursula , Asch Ester , Berger Peter , Jenewein Brigitte , Saurwein-Teissl Maria , Grubeck-Loebenstein Beatrix , Fuchs Dietmar
Published: August 2013

Neopterin is produced from human monocyte-derived macrophages and dendritic cells upon Stimulation with interferon-y, and increased neopterin concentrations thus indicate cell-mediated immune activation. In healthy individuals increasing neopterin concentrations are found with increasing age, which is also evident from the agedependency of reference values of serum neopterin concentrations. Increase of neopterin concentrations in the elderly may relate to, e.g., altered T lymphocyte differentiation with age. In this study, serum neopterin concentrations of 138 persons (median age: 34 years; interquartile range 29.0 - 67.8 years) were investigated and compared to age and to the percentage of CD28+CD45RA+ or CD28+CD45RO+ subsets among CD8+ T cells. With increasing age, the percentage of CD28+CD45RA+ in CD8+ T-cells decreased (Spearman's rank correlation coefficient: rs = -0.561; p < 0.0001) accompanied by an increase of the percentage of CD28+CD45RO+ in CD8+ T-cells (rs = +0.221; p < 0.01). Serum neopterin concentrations increased with age (rs = -+0.541; p < 0.0001). This increase of neopterin concentration was accompanied by a decreased percentage of CD28+CD45RA+ in CD8+ T-cells (r+ = -0.287; p < 0.001). Multivariate analyses revealed that the inverse relationship between the percentage of CD28+CD45RA+ in CD8+ T-cells and neopterin concentrations was at least partly independent from age. Thus, investigation allows to conclude that an increase of neopterin concentrations with older age is accompanied by a loss of naive CD28+CD45RA+ CD8+ T-cells. Data suggest that the subset of CD28+CD8+ T-cells, which is developing in states of sustained immune activation, is important for a chronic production of interferon-γ which in turn gives rise to increased neopterin concentrations.
Possibility of the Nonenzymatic Conversion of 6-(1'-Oxo-2'-hydroxypropyl)- Tetrahydropterin to Sepiapterin
Authors: Sawada Hiroshi , Shimura Natumi , Takikawa Shin-Ichiro , Lino Teruhiko
Published: August 2013

Tetrahydrobiopterin (BH4) is a cofactor for aromatic amino acid hydroxylases and nitric oxide synthase. The biosynthetic pathway of BH4 from 6-pyruvoyl-tetrahydropterin (PPH4) includes two reduction steps catalyzed by sepiapterin rcductasc (SPR). PP1I4 is reduced to 6-( 1 '-oxo-2'-hydroxypiOpyl)-tetrahydropterin (l'-OXPH4 ) or 6- ( r-hydroxy-2'-oxopropyl)-tetrahydropterin (2'-OXPH4), which is further converted to BH4. However, patients with SPR deficiency show normal urinary excretion of pterins without hyperphenylalaninemia, suggesting the existence of another BH4 biosynthetic pathway, which is not concerned with SPR in humans. Blau et al. proposed a BH4 biosynthetic salvage pathway containing nonenzymatic conversion of l'-OXPH4 to sepiapterin. In this study, the possibility of the nonenzymatic conversion of l'-OXPH4 to sepiapterin was examined by using silkworm carbonyl reductase (CR 1) and human monomeric carbonyl reductase. Since l'-OXPH4 has been suggested to be nonenzymatically converted into sepiapterin, in an incubation mixture containing PPH4 and silkworm CR I, sepiapterin was determined by its derivative as biopterin. No sepiapterin was detected in the incubation mixture when the mixture, containing 800 pmol of l'-OXPH4, was further incubated at 37°C for 2 h in darkness. This result suggests that the rate of nonenzymatic formation of sepiapterin from l'-OXPH4 is quite low. The findings obtained here indicate that the proposed pathway in which a nonenzymatic conversion of l'-OXPH4 to sepiapterin occurs may be difficult or unlikely to proceed in humans.
Neopterin Levels and Immune Activation in the Blood of Children with Down’s Syndrome
Authors: Licastro F. , Chiappelli M. , Porcellini E. , Rustica M. , Corsi M.M.
Published: August 2013

Patients with AD often show altered levels of some immune molecules in their peripheral blood which correlate with cognitive impairment. Downs' syndrome (DS) subjects are at high risk of developing Alzheimer's disease (AD). Here we studied immune molecules, such as interleukin-6 (IL-6), C reactive protein (CRP) and neopterin, in the blood of non demented children with DS to investigate whether altered peripheral immune phenotype could be present in this subjects without dementia, many years before the presentation of clinical signs of cognitive deterioration. Plasma levels of neopterin and IL-6 were measured by commercially available ELISA kits, whereas plasma CRP concentration was evaluated by nephelometric immunoassay technique. We studied a group of 40 patients with DS, 20 healthy controls and 100 patients w ith AD. Plasma levels of IL-6 and CRP were significantly higher in DS than in control children. The increase of IL-6 and CRP from DS children was similar to that found in elderly patients with clinical AD. In the present research we have also studied blood levels of neopterin which were in the normal range either in DS or control. Increased or normal levels of this metabolite have been found in the blood of AD patients. However, increased blood neopterin was likely to be only elevated in patients with advanced clinical stage of AD. Peripheral altered immune phenotype in healthy young subjects with DS might be an early sign of CNS alterations leading many years later to cognitive deterioration and dementia.
A Herbal Multicomponent Mixture Effective in Suppressing Biochemical Pathways in Mitogen-stimulated Human Peripheral Blood Mononuclear Cells
Authors: Neurauter Gabriele , Wirleitner Barbara , Schennach Harald , Ueberall Florian , Fuchs Dietmar
Published: August 2013

Extract of traditional Tibetan herbal remedy Padma 28 revealed suppressive effects on neopterin production and tryptophan degradation in mitogen-stimulated peripheral blood mononuclear cells (PBMC). One of the questions was to asses the robustness of the Tibetan way of formulating herbal multicomponent medicines. Can small changes affect the effectiveness of the formula? In this study, effect of a derivative multicomponent mixture was investigated in stimulated and unstimulated human PBMC in vitro. Neopterin production and tryptophan degradation were measured in supernatants of PBMC in the presence or absence of mitogens phytohacmagglutinin and concanavalin A. Stimulation of PBMC induced neopterin formation and tryptophan degradation, and the herbal multicomponent mixture inhibited both immunobiochemical effects in a dose-dependent way. Higher concentrations were more effective and were able to completely block the pathways induccd upon mitogenic stimulation. When comparing the results obtained with those observed earlier using Padma 28, there was no obvious difference between the two different preparations. Data allow to conclude that Padma 28 and its modified version is equally able to suppress immunobiological effects in stimulated PBMC.
Molecular Analysis of mps Operon Involved in Monapterin Syntliesis in Escherichia Coli
Authors: Ahn Chiyoung , Kim Mikyoeng , Lee Soojin , Kim Jackwang , Hwang Deogsu , Park Kyungmoon , Yim Jeongbin
Published: August 2013

Two genes, mpsA and mpsB, constitute an operon in the synthesis of monapterin in E. coli. Expression of mpsA, the structural gene for dihydroneopterin triphosphate 2'-epimerase, from its native promoter, required mpsB. Cotransfonnation of mpsB excludes the possibility that the MpsB is a transactivator protein for mpsA expression.
Urinary Neopterin in Patients with upper Gastrointestinal, Biliary and Pancreatic Carcinomas
Authors: Melichar Bohuslav , Solichová Dagmar , Svobodová Ivcta , Urbánek Lubor , Melicharová Karolina
Published: August 2013

Increased urinary neopterin has been associated with advanced disease and poor prognosis in patients with colorectal carcinoma, but less is known about urinary neopterin in other gastrointestinal tumors. We have investigated urinary neopterin in 53 patients with carcinomas of the upper gastrointestinal tract, pancreas and biliary tract. Conipared to controls, urinary neopterin was increased in patients with gastric carcinoma, pancreatic Carcinoma, cholangiocarcinoma and gallbladder carcinoma. Urinary neopterin was a significant prognostic indicator of survival in univariate as well as multivariate analyses. No significant change in urinary neopterin concentrations was observed during the short follow-up, but increased urinary neopterin concentration at the end of followup was associated with poor prognosis. In conclusion, significantly increased urinary neopterin concentrations were observed in the present cohort of patients. Urinary neopterin is an independent prognostic indicator in patients with carcinomas of the upper gastrointestinal tract, biliary tree and pancreas.
Effect of 5,6,7,8-Tetrahydrobiopterin (BH4) on γ-Ray-induced Micronucleus Frequency in RAW264.7 Cells
Authors: Hori Mayumi , Kojima Shuji
Published: August 2013

The effect of 5,6,7,8-tetrahydrobiopterin (BH4), an endogenous antioxidant, on γ-ray-induced micronucleus frequency was examined in RAW264.7 cells. Exogenously added BH4 reduced the γ-ray-induced micronucleus frequency. Treatment with 1 mM sepiapterin, a biosynthetic precursor of BH4, also significantly reduced the micronucleus frequency induced by 3-10 Oy y-rays, by 20-35(/o at 1 8 h post-treatment. The reducing cffect of SP on γ-ray-induced micronucleus frequency was blocked by N-acetyl-5-hydroxytryptaminc and methotrexate, which are inhibitors of BH4 biosynthesis. These results suggest that intracellular BH4 biosynthesized from sepiapterin is involved in the reducing effect of SP on γ-ray-induced micronucleus frequency. To examine possible mechanisms underlying this action, changes of intracellular BH4 concentration after sepiapterin treatment were examined. Intracellular BH4 concentration peaked at 6 h and was maintained at a high level until 24 h after sepiapterin treatment. However, the γ-ray-induced micronucleus frequency at 6 h post-treatment with sepiapterin showed no change in comparison with that after irradiation alone. These results indicate that the reducing effect of BH4 on γ-ray-induced micronucleus frequency is not necessarily due to antioxidant activity, but may involve other mechanisms.
Photoinduced Generation of H2O2 and O2•- by 6-formylpterin in Aqueous Solutions
Authors: Petroselli Gabriela , Bartsch Jonas Martin , Thomas Andrés H.
Published: August 2013

6-Formylpterin is one of the oxidized pterins that accumulate in the white skin patches of patients affected by vitiligo. Studies of photoinduced generation of hydrogen peroxide (H2O2 ) and superoxide anion radical (O2• ) by formylpterin in acidic and alkaline aqueous solutions at 350 nm and room temperature have been performed. The photochemical processes were followed by UV-V1S spectrophotometry and enzymatic methods for H2O2 and O2•- determination. When formylpterin is irradiated a red intermediate, that has been proposed to be 6-carboxy- 5,8-dihydropterin, is generated in an O2
-independent process. In the presence of air that intermediate reacts with O2 to yield H2O2 and 6-carboxyptcrin. In anaerobic conditions it undergoes a thermal O2-independent reaction which leads to a non-identified product without generation of H202 . The rate constants of such a process were determined to be 0.011 min 1 and 0.044 min1 at pH 5.4 and 10.5, respectively. (O2 · ), is also generated during photooxidation of formylpterin, probably as a consequence of the electron transfer from the red intermediate to O2 . The biomedical importance of photoinduced generation of H2O2 and O2• is discussed.
New Insights into Ophthalmology: Introduction of SELDI-TOF in Combination with Molecular Modelling for the Analysis of Aqueous Humour. Principle and First Results.
Authors: Tilz Gernot P. , Wiltgen Marco , Demel Ulrike , Faschinger Christoph , Scherbichler Wulf
Published: August 2013

We present the introduction of a new generation of techniques for early and specific diagnosis of inflammatory, immune and degenerative eye diseases. We concentrate on the applications of the SELDI-TOF (Surface enhanced laser desorption ionisation - time of flight) mass spectroscopy in combination with molecular modelling and visualization for the analysis of the aqueous humour. For our study we used aqueous humour from 25 patients undergoing cataract operation. SELDI-TOF consists on one part of an apparatus allowing the laser bombarding of molecules on a solid surface and on the other part on a system which measure the time of flight of the molecules. During the measurement the molecules are liberated from the matrix and carried to the detector. Specific proteins can be identified by the characteristic peaks of the spectrogram. Albumin and gamma-globulin were found to a considerable extend in the aqueous humour. An increased amount has been detected in inflammatory humour. The quantity may reflect some underlying complications such as inflammation and animate for further research on the spectrum of proteins and peptides released by underlying eye disorder. SELDI-TOF delivers characteristic peptide mass fingerprints, which can be used as input for the prediction of the tertiary protein structure with homology modelling. Structural deviations between a genuine protein and a mutated can be an indicator about the underlying disease, paving the way for successful diagnostic and therapy. The combination of two new technologies namely SELDI-TOF and molecular modelling may offer a broad spectrum for the differential diagnosis of some eye diseases.
In Vitro Effect of Neopterin on Splenic Mast Cell Development in Senescence Accelerated Mice (SAM)
Authors: Harada Tomonori , Tsuboi Isao , Yuda Miyuki , Wakasugi Kazunori , Aizawa Shin
Published: August 2013

Neopterin is produced by monocytes and is a useful biomarker of inflammatory responses. We found that neopterin enhances granulopoiesis, but suppresses B-lymphopoiesis triggered by the positive- and negative regulations of cytokines produced by stromal cells in mice. Furthermore, neopterin suppressed the colony formation of mast cell progenitor (CFU-mast) from bone marrow cells in in vitro culture system. In this study, neopterin was also found to regulate the proliferation and differentiation of splenic CFU-mast in vitro as observed in that from bone marrow, which was confirmed in the mouse model of senescent stromal-cell impairment (SCI). In non- SCI mice (=less senescent stage of SCI mice), neopterin also decreased the number of colonies of interleukin-3 (IL-3)-dependent mast-cell progenitor cells (CFU-mast) from unfractionated spleen cells, but not that from the lineage-negative (fractionated) spleen cell population without stromal cells in a semisolid in vitro culture system. In contrast, in a case of SCI mice, the treatment with neopterin did not decrease the number of colonies of IL-3- dependent mast-cell progenitor cells (CFU-mast) from unfractionated spleen cells. These results suggest that, firstly, neopterin decrease the number of colonies of IL-3-dependent CFU-mast by stimulating splenic stromal cells, and secondly, such neopterin function becomes declined during senescence because of an impaired stromalcell function.
A Modified Microbiological Method for Determination of Folate Levels in Erythrocyte and Plasma
Authors: Sipahi Hande , Baydar Terken , Ozalp Meral , Sahin Gonul
Published: August 2013

Pteridines are natural heterocyclic compounds and they are generally divided into two main groups which are denominated as conjugated and unconjugated pteridines. Conjugated pteridines are the folate derivatives containing p-aminobenzoate and glutamate. Folate is a normal component of the cell. Folate derivatives play a crucial role in important biochemical pathways such as purine and pyrimidine biosynthesis, conversion of serine to glycine, histidine catabolism, methionine synthesis and detoxification reactions of certain xenobiotics, in which single carbon transfer is required. Folate deficiency has been proven to play a role in the pathogenesis of certain diseases. Additionally, exposure to some xenobiotics and prolonged use of some drugs may lead to folate deficiency. Serum, plasma and especially erythrocyte folate concentrations are generally used as biomarkers of folate pool. Therefore the present study was undertaken to establish an easy applicable, economic, accurate, sensitive, specific and reproducible microbiological method by using L. rhamnosus in our laboratory. Following the establishment of the method its application was carried out in blood samples of 46 volunteers. Mean value of folate levels in erythrocyte were found 359.7 ± 133.3 ng/ml, while mean plasma folate levels were determined 27.3 ± 12.4 ng/ml. In erythrocyte, the average recovery was 103.0 ± 17.7% (mean ±SD), in plasma the average recovery was 101.0 ± 1.7% (mean ±SD) for folinic acid concentrations at 10, 25 and 50 ng/ml. The CVs were 15.1 ± 5.6% (mean ± SD) for within-run and 7.2 ± 3.9% (mean ± SD) for between-run precisions. In the present study, a modified microbiological method for folate analysis which can be applied to biological material, has been established.