bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of hypoxia on the transcription pattern of subunit isoforms and the kinetics of cytochrome c oxidase in cortical astrocytes and cerebellar neurons
Authors: Horvat Susann , Beyer Cordian , Arnold Susanne 
Published: September 2006

AbstractBrain energy metabolism essentially depends on the availability of oxygen representing the energetic substrate for cytochrome c oxidase (COX). The catalytic activity of mammalian COX is regulated by binding of ATP to the N‐terminus of subunit IV. This causes an allosteric inhibition of the enzyme at a high energy level and thus plays an important role in adjusting energy production to cellular energy requirements. We have studied COX activity in cortical astrocytes and cerebellar granule cells after normoxia and hypoxia treatment. Differences in the kinetic behaviour of COX from these two brain cell types can be addressed to a differential, but cell type‐specific, expression of the COX subunit IV‐2 isoform. Besides COX isoform IV‐1, which is ubiquitously transcribed in all mammalian tissues, we also detected low levels of COX isoform IV‐2 in cerebellar neurons, but not in cortical astrocytes. Under conditions of oxygen deprivation, transcription of COX IV‐2 is induced in astrocytes and further up‐regulated in cerebellar granule cells. Elevated transcription levels of the COX IV‐2 isoform are accompanied by an abolition of the allosteric inhibition of COX by ATP. We conclude that the presence of the COX isoform IV‐2 suppresses the sensitivity of COX to its allosteric regulator ATP and overrules the regulation of COX by the cellular energy level. This suggests a pivotal role of COX as an oxygen sensor for brain function.
Isoform‐ and subcellular fraction‐specific differences in hippocampal 14‐3‐3 levels following experimentally evoked seizures and in human temporal lobe epilepsy
Authors: Schindler Clara K. , Heverin Maura , Henshall David C. 
Published: September 2006

Abstract14‐3‐3 proteins are a family of signaling molecules involved in diverse cellular functions, which can mediate anti‐apoptotic effects. Seizure‐induced neuronal death may involve programmed (apoptotic) cell death pathways and is associated with a decline in brain 14‐3‐3 levels. Presently, we investigated the subcellular localization and effects of seizures on isoforms of 14‐3‐3 in rat hippocampus, and contrasted these to findings in human temporal lobe epilepsy (TLE). All brain isoforms of 14‐3‐3 were detected in the cytoplasmic compartment of rat hippocampus, while 14‐3‐3γ and ‐ζ were also present in mitochondrial and microsome‐enriched fractions. Focally evoked seizures in rats significantly reduced 14‐3‐3γ levels within the microsome‐enriched compartment at 4 h, with similar responses for 14‐3‐3ζ, while cytoplasm‐localized 14‐3‐3β, ‐ε and ‐η remained unchanged. Analysis of human autopsy control hippocampus revealed similar 14‐3‐3 isoform expression profiles. In TLE samples, the microsome‐enriched fraction also showed differences, but here 14‐3‐3ε and ‐ζ levels were higher than controls. TLE sample 14‐3‐3 isoform abundance within the cytoplasmic fraction was not different to controls. This study defines the subcellular localization of 14‐3‐3 isoforms in rat and human hippocampus and identifies the microsome‐enriched fraction as the main site of altered 14‐3‐3 levels in response to acute prolonged and chronic recurrent seizures.
Temporal coupling of cyclic AMP and Ca2+/calmodulin‐stimulated adenylyl cyclase to the circadian clock in chick retinal photoreceptor cells
Authors: Chaurasia Shyam S. , Haque Rashidul , Pozdeyev Nikita , Jackson Chad R. , Iuvone P. Michael 
Published: September 2006

AbstractcAMP signaling pathways play crucial roles in photoreceptor cells and other retinal cell types. Previous studies demonstrated a circadian rhythm of cAMP level in chick photoreceptor cell cultures that drives the rhythm of activity of the melatonin synthesizing enzyme arylalkylamine N‐acetyltransferase and the rhythm of affinity of the cyclic nucleotide‐gated channel for cGMP. Here, we report that the photoreceptor circadian clock generates a rhythm in Ca2+/calmodulin‐stimulated adenylyl cyclase activity, which accounts for the temporal changes in the cAMP levels in the photoreceptors. The circadian rhythm of cAMP in photoreceptor cell cultures is abolished by treatment with the l‐type Ca2+ channel antagonist nitrendipine, while the Ca2+ channel agonist, Bay K 8644, increased cAMP levels with continued circadian rhythmicity in constant darkness. These results indicate that the circadian rhythm of cAMP is dependent, in part, on Ca2+ influx. Photoreceptor cell cultures exhibit a circadian rhythm in Ca2+/calmodulin‐stimulated adenylyl cyclase enzyme activity with high levels at night and low levels during the day, correlating with the temporal changes of cAMP in these cells. Transcripts encoding two of the Ca2+/calmodulin‐stimulated adenylyl cyclases, type 1 and type 8 (Adcy1 and Adcy8), displayed significant daily rhythms of mRNA expression under a light–dark cycle, but only the Adcy1 transcript rhythm persisted in constant darkness. Similar rhythms of Adcy1 mRNA level and Ca2+/calmodulin‐stimulated adenylyl cyclase activity were observed in retinas of 2‐week‐old chickens. These results indicate that a circadian clock controls the expression of Adcy1 mRNA and Ca2+/calmodulin‐stimulated adenylyl cyclase activity; and calcium influx into these cells gates the circadian rhythm of cAMP, a key component in the regulation of photoreceptor function.
A nicotinic acetylcholine receptor mutation (Y151S) causes reduced agonist potency to a range of neonicotinoid insecticides
Authors: Liu Zewen , Williamson Martin S. , Lansdell Stuart J. , Han Zhaojun , Denholm Ian , Millar Neil S. 
Published: September 2006

AbstractNeonicotinoid insecticides are potent selective agonists of insect nicotinic acetylcholine receptors (nAChRs). Since their introduction in 1991, resistance to neonicotinoids has been slow to develop, but it is now established in some insect field populations such as the planthopper, Nilaparvata lugens, a major rice pest in many parts of Asia. We have reported recently the identification of a target‐site mutation (Y151S) within two nAChR subunits (Nlα1 and Nlα3) from a laboratory‐selected field population of N. lugens. In the present study, we have examined the influence of this mutation upon the functional properties of recombinant nAChRs expressed in Xenopus oocytes (as hybrid nAChRs, co‐expressed with a rat β2 subunit). The agonist potency of several nicotinic agonists has been examined, including all of the neonicotinoid insecticides that are currently licensed for either crop protection or animal health applications (acetamiprid, clothianidin, dinotefuran, imidacloprid, nitenpyram, thiacloprid and thiamethoxam). The Y151S mutation was found to have no significant effect on the maximal current (Imax) observed with the endogenous agonist, acetylcholine. In contrast, a significant reduction in Imax was observed for all neonicotinoids (the Imax for mutant nAChRs ranged from 13 to 81% of that observed on wild‐type receptors). In addition, nAChRs containing the Y151S mutation caused a significant rightward shift in agonist dose–response curves for all neonicotinoids, but of varying magnitude (shifts in EC50 values ranged from 1.3 to 3.6‐fold). The relationship between neonicotinoid structure and their potency on nAChRs containing the Y151S target‐site mutation is discussed.
Life‐threatening thrombocytopenia and nephrotic syndrome due to focal segmental glomerulosclerosis associated with pegylated interferon α‐2b and ribavirin treatment for hepatitis C
Authors: Alves Couto Cláudia , Costa Faria Luciana , Dias Ribeiro Daniel , De Paula Farah Kátia , De Melo Couto Osvaldo Flávio , De Abreu Ferrari Teresa Cristina 
Published: September 2006

Abstract: Background:Interferon‐α (IFN‐α)and ribavirin combination therapy for chronic infection with hepatitis C virus produces a number of well‐described side effects. Combination therapy with pegylated interferon (PEG‐IFN) yields an adverse event profile similar to that observed with the standard IFN, although the frequency of certain adverse events may vary according to the preparation.Case report:We report the case of a 44‐year‐old man who was treated with ribavirin and PEG‐IFN‐α‐2b for chronic hepatitis C and developed two rare side effects simultaneously on the 16th week of therapy: severe thrombocytopenia and nephrotic syndrome due to focal segmental glomerulosclerosis. The antiviral treatment was immediately interrupted and the patient received immunosuppressive therapy. He promptly recovered from the thrombocytopenia and partially and slowly from the nephrotic syndrome. To our knowledge, this is the first case reported of the development of such complications at the same time.
Clinical application of tissue‐engineered transplants. Part I: mucosa
Authors: Sauerbier Sebastian , Gutwald Ralf , Wiedmann‐Al‐Ahmad Margit , Lauer Günter , Schmelzeisen Rainer 
Published: September 2006

AbstractObjectives: The study series aims at testing the feasibility of the clinical application of tissue‐engineered oral mucosa. The preliminary results were gathered over a period varying from 6 months to 12 years depending on the surgical method.Methods: Tissue‐engineered oral mucosa was used to cover defects in various surgical procedures like vestibuloplasty (n=42), freeing of the tongue (n=10), prelaminating the radial flap (n=5) and reconstruction of the urethra (n=16). In all interventions small samples of oral mucosa were harvested, cut into small pieces, resuspended in culture medium and seeded into a culture flask. Cultured keratinocytes were transferred onto membranes which then were used to cover mucosal defects in the oral cavity.Results: To gain a graft of 15 cm2 size a mucosa biopsy of 4–8 mm2 and 40 ml autologous patients serum is needed. Tissue‐engineered oral mucosa was applied successfully in all four surgical methods. Six months after transplantation a regular epithelial layering with a histological delimitation of the stratum, epithelial crest and a strong basal membrane appeared. According to the reception site the tissue engineered oral mucosa differentiated in several ways.Conclusion: Tissue‐engineered oral mucosa fulfils the requirements for clinical routine. With view to healing time and outcome it does not appear to be superior to regular harvested oral mucosa transplants. Because of a smaller harvesting defect and primary wound closure at the actual operation site the patients' convenience is increased. Thus this method reduces morbidity and advances the quality of life.
A novel HLA‐B allele, B*5612, identified by sequence‐based typing method
Authors: Chu C‐C. , Chang H‐L. , Chen Z‐S. , Lee H‐L. , Lin M. 
Published: September 2006

SummaryHLA‐B*5612, found in Taiwan using sequence‐based typing method, was identical to HLA‐B*5502 in exon 2 but differed in exon 3 by 10 nucleotide substitutions at positions 353–420 leading to five amino acid change at codon 94, 95, 97, 103 and 116. As this sequence motif was not found in the Asian population, it is likely that HLA‐B*5612 is the product of a complex mechanism of implying a dual gene conversion event.
Increase in interleukin‐6 following arterial injury is related to insulin resistance, the −174G→C polymorphism and complex plaque morphology
Authors: Marso S. P. , House J. A. , Hopkins P. J. 
Published: September 2006

SummaryInterleukin‐6 (IL‐6) is associated with many disease states in humans. We prospectively sought to determine whether IL‐6 levels increased following percutaneous coronary intervention (PCI) in the absence of myonecrosis. Additionally, we systematically assessed other clinical and anatomic factors associated with IL‐6 levels in a population of patients with coronary atherosclerosis undergoing PCI. Blood samples were collected from 117 patients at baseline, 8 and 16 h following PCI. Samples were assayed for IL‐6, creatine kinase‐myocardial band (CK‐MB), troponin‐I (Tn‐I), high sensitivity C‐reactive protein, glucose, haemoglobin A1c, and a lipid profile. Genotyping of the −174G→C polymorphism of the IL‐6 gene was performed. IL‐6 levels increased following PCI among the study group (slope = 0.4 pg/mL/h, P = 0.001). IL‐6 levels increased to a similar degree in the absence of myonecrosis. Patients with the XC genotype (either having the GC or the CC allele) had higher IL‐6‐values at baseline compared to GG genotype patients (4.9 ± 6.4 vs. 2.6 ± 1.8 pg/mL, P = 0.02). Multivariable predictors of detectable baseline IL‐6 levels included XC genotype (odds ratio [OR]: 4.14, 95% CI 1.58–10.82, P = 0.004), ACC/AHA type C lesion classification (OR: 4.08, 95% CI 1.54–10.84, P = 0.005), elevated baseline Tn‐I (OR: 3.31, 95% CI 1.16–9.43, P = 0.025), diabetes (OR: 3.00, 95% CI 1.11–8.09, P = 0.030), and waist circumference (OR: 1.49, 95% CI 1.08–2.06, P = 0.015). Predictors of peak IL‐6 following PCI included the XC genotype (estimate 1.4, 95% CI 1.06–1.87, P = 0.019), homeostasis model assessment (estimate 0.99, 95% 0.982–0.999, P = 0.042) and baseline Tn‐I > upper limit of normal (estimate 0.7, 95% CI 0.50–0.96, P = 0.039). Lastly, IL‐6 increased following PCI even in the absence of myonecrosis as measured by Tn‐I elevation. IL‐6 levels are also related to the −174G→C polymorphism, arterial injury, lesion complexity, and insulin resistance.
A novel HLA‐B*2730 allele found in a Slovene patient affected with IgA nephropathy
Authors: Vidan‐Jeras B. , Kunilo S. , Fae I. , Kandus A. , Fischer G. F. 
Published: September 2006

SummaryA novel allele HLA‐B*2730 and the haplotype HLA‐A*03‐B*2730‐Cw*02‐DRB1*16‐DRB5 have been found in a Slovene patient and his mother. The exon 2 sequence is identical to that of HLA‐B*2702, and the exon 3 sequence is identical to that of HLA‐B*2719. A possible mechanism for the generation of B*2730 is a gene conversion event.
Jet Engine Model for Control and Real-Time Simulations
Authors: Lichtsinder Michael , Levy Yeshayahou 
Published: September 2006

Abstract
The main objective of this paper is development of a simple real-time transient performance model for jet engine control. A jet engine arrives to its most dangerous condition during transient operation that may be triggered by fast changes of the input fuel command signal. Thus, the control system specifications are formulated to specify the maximal variance of the fuel flow command (from idle to maximum power level) during transient maneuver. Linear and piecewise-linear techniques are not always convenient and appropriate for turbine engine controller design. An alternative quasilinear simple/fast engine model is discussed in this paper. This model has maximum accuracy for maximal variance of the fuel flow input command in accordance to the jet engine control system specifications. The fast model is obtained using the Novel Generalized Describing Function, proposed for investigation of nonlinear control systems. The paper presents the Novel Generalized Describing Function definition and then discusses the application of this technique for the development a fast turbine engine simulation suitable for control and real-time applications. Simulation results are compared between the conventional and fast models and found to provide good agreement.
Fourier Neural Networks and Generalized Single Hidden Layer Networks in Aircraft Engine Fault Diagnostics
Authors: Tan H. S. 
Published: September 2006

Abstract
The conventional approach to neural network-based aircraft engine fault diagnostics has been mainly via multilayer feed-forward systems with sigmoidal hidden neurons trained by back propagation as well as radial basis function networks. In this paper, we explore two novel approaches to the fault-classification problem using (i) Fourier neural networks, which synthesizes the approximation capability of multidimensional Fourier transforms and gradient-descent learning, and (ii) a class of generalized single hidden layer networks (GSLN), which self-structures via Gram-Schmidt orthonormalization. Using a simulation program for the F404 engine, we generate steady-state engine parameters corresponding to a set of combined two-module deficiencies and require various neural networks to classify the multiple faults. We show that, compared to the conventional network architecture, the Fourier neural network exhibits stronger noise robustness and the GSLNs converge at a much superior speed.
Design of Aero Gas Turbines Using Hydrogen
Authors: Haglind Fredrik , Singh Riti 
Published: September 2006

AbstractMainly owing to the dwindling fossil oil resources and the environmental concerns of discharging greenhouse gases into the atmosphere, it is essential to find an alternative to kerosene for civil aviation. This paper covers the main effects on aero engines when changing to hydrogen fuel. Particularly, emission and performance issues are discussed, but some design matters are also covered. By simply changing to hydrogen, small engine performance gains may be obtained. The results of the calculations suggest that there is the potential to design a combustion system using hydrogen that produces less NOx emissions than any system using kerosene.
A Review of Wave Rotor Technology and Its Applications
Authors: Akbari Pezhman , Nalim Razi , Mueller Norbert 
Published: September 2006

AbstractThe objective of this paper is to provide a succinct review of past and current research in developing wave rotor technology. This technology has shown unique capabilities to enhance the performance and operating characteristics of a variety of engines and machinery utilizing thermodynamic cycles. Although there have been a variety of applications in the past, this technology is not yet widely used and is barely known to engineers. Here, an attempt is made to summarize both the previously reported work in the literature and ongoing efforts around the world. The paper covers a wide range of wave rotor applications including the early attempts to use wave rotors, its successful commercialization as superchargers for car engines, research on gas turbine topping, and other developments. The review also pays close attention to more recent efforts: utilization of such devices in pressure-gain combustors, ultra-micro gas turbines, and water refrigeration systems, highlighting possible further efforts on this topic. Observations and lessons learnt from experimental studies, numerical simulations, analytical approaches, and other design and analysis tools are presented.
Tumor Stromal-Derived Factor-1 Recruits Vascular Progenitors to Mitotic Neovasculature, where Microenvironment Influences Their Differentiated Phenotypes
Authors: Aghi Manish , Cohen Kenneth S. , Klein Rachael J. , Scadden David T. , Chiocca E. Antonio 
Published: September 2006

Abstract
Mechanisms underlying tumor vasculogenesis, the homing and engraftment of bone marrow–derived vascular progenitors, remain undefined. We hypothesized that tumor cell–secreted factors regulate vasculogenesis. We studied vasculogenic and nonvasculogenic intracranial murine gliomas. A PCR screen identified stromal-derived factor-1 (SDF-1/CXCL12) and vascular endothelial growth factor (VEGF) expression by vasculogenic glioma cells and spontaneously arising vasculogenic tumors in NF1+/−:Trp53+/− mice, but not by nonvasculogenic glioma cells. Enforced SDF-1, not VEGF, expression in nonvasculogenic cells caused vasculogenesis. Combined SDF-1 and VEGF expression augmented vasculogenesis over SDF-1 expression alone. Blocking SDF-1 receptor CXCR4 reduced short-term homing and long-term engraftment of vascular progenitors. Implanting tumor cells secreting SDF-1 was therefore necessary and sufficient to incorporate marrow-derived precursors into tumor endothelium. SDF-1 seemed to exert these effects by acting locally intratumorally and did not cause an efflux of marrow-derived progenitors into circulation. Tumor microenvironment determined additional fates of marrow-derived cells. Hypoxia, observed with ectopic s.c. murine tumors at levels approximating that of intracranial human glioblastoma, interacted with tumor-secreted SDF-1 to expand engrafted vascular progenitor differentiated phenotypes to include pericytes as well as endothelium. In contrast, less hypoxic orthotopic intracranial murine gliomas contained only marrow-derived endothelium without marrow-derived pericytes. Furthermore, we found that vasculogenesis is significant for tumors because it generates endothelium with a higher mitotic index than endothelium derived from local sources. Although CXCR4 blockade selectively targeted endothelium generated by vasculogenesis, completely inhibiting vessel formation may require combination therapy targeting locally derived and marrow-derived endothelium. (Cancer Res 2006; 66(18): 9054-64)
Chemosensitization by Knockdown of Adenine Nucleotide Translocase-2
Authors: Le Bras Morgane , Borgne-Sanchez Annie , Touat Zahia , El Dein Ossama Sharaf , Deniaud Aurélien , Maillier Evelyne , Lecellier Gael , Rebouillat Dominique , Lemaire Christophe , Kroemer Guido , Jacotot Etienne , Brenner Catherine 
Published: September 2006

Abstract
Mitochondrial membrane permeabilization (MMP) is a rate-limiting step of apoptosis, including in anticancer chemotherapy. Adenine nucleotide translocase (ANT) mediates the exchange of ADP and ATP on the inner mitochondrial membrane in healthy cells. In addition, ANT can cooperate with Bax to form a lethal pore during apoptosis. Humans possess four distinct ANT isoforms, encoded by four genes, whose transcription depends on the cell type, developmental stage, cell proliferation, and hormone status. Here, we show that the ANT2 gene is up-regulated in several hormone-dependent cancers. Knockdown of ANT2 by RNA interference induced no major changes in the aspect of the mitochondrial network or cell cycle but provoked minor increase in mitochondrial transmembrane potential and reactive oxygen species level and reduced intracellular ATP concentration without affecting glycolysis. At expression and functional levels, ANT2 depletion was not compensated by other ANT isoforms. Most importantly, ANT2, but not ANT1, silencing facilitated MMP induction by lonidamine, a mitochondrion-targeted antitumor compound already used in clinical studies for breast, ovarian, glioma, and lung cancer as well as prostate adenoma. The combination of ANT2 knockdown with lonidamine induced apoptosis irrespective of the Bcl-2 status. These data identify ANT2 as an endogenous inhibitor of MMP and suggest that its selective inhibition could constitute a promising strategy of chemosensitization. (Cancer Res 2006; 66(18): 9143-52)