bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fluid‐induced wall shear stress in anthropomorphic brain aneurysm models: MR phase‐contrast study at 3 T
Authors: Ahn Sinyeob , Shin Dongsuk , Tateshima Satoshi , Tanishita Kazuo , Vinuela Fernando , Sinha Shantanu 
Published: May 2007

AbstractPurposeTo study spatial and temporal distribution of wall shear stress (WSS) of intracranial aneurysm models using magnetic resonance phase contrast (MR‐PC) imaging, and to compare results to those obtained in our previous study using laser Doppler velocimetry (LDV).Materials and MethodsHigh‐resolution MR‐PC imaging was performed on aneurysm models created from 3D in vivo data of a basilar artery (BA) tip and a middle cerebral artery (MCA) aneurysm. WSS was measured by calculating the rate of shearing strain using image postprocessing techniques. WSS was characterized using several parameters, including average WSS and oscillatory shear index (OSI).ResultsBoth aneurysms showed the highest WSS at an ostium. A bleb region in the BA tip and a dome region in the MCA aneurysm were consistently exposed to high WSS within a small local area with high spatial variation and little temporal change in comparison to other aneurysmal regions. High correlation was noted for the spatial distribution at the peak systole between the MR‐PC and the LDV studies, with the correlation coefficient value of 77% to 81%.ConclusionMR‐PC imaging showed good agreement with the reference LDV study, confirming its potential to study hemodynamics of physiologically realistic in vitro intracranial aneurysm models. Characteristic patterns of WSS, such as high spatial variation and absence of temporal variation, combined with locally increased high WSS as determined by MR‐PC imaging, may elucidate the effect of WSS on aneurysmal development and rupture. J. Magn. Reson. Imaging 2007;25:1120–1130. © 2007 Wiley‐Liss, Inc.
Soft‐tissue tumors evaluated by line‐scan diffusion‐weighted imaging: Influence of myxoid matrix on the apparent diffusion coefficient
Authors: Maeda Masayuki , Matsumine Akihiko , Kato Hiroya , Kusuzaki Katsuyuki , Maier Stephan E. , Uchida Atsumasa , Takeda Kan 
Published: May 2007

AbstractPurposeTo compare the apparent diffusion coefficients (ADCs) of myxoid and nonmyxoid soft‐tissue tumors using line‐scan diffusion‐weighted imaging (LSDWI), and to investigate the myxoid matrix influence on ADCs of soft‐tissue tumors.Materials and MethodsThis study enrolled 44 patients with soft tissue tumors. They were divided into two groups: one with myxoid‐containing soft‐tissue tumors (N = 23) and the other with nonmyxoid soft‐tissue tumors (N = 21). The 44 patients were also classified histologically into 26 with malignant soft‐tissue tumors and 18 with benign soft‐tissue tumors. LSDWI was performed using b values of 5 and 1000 second/mm2. The ADCs of the tumors were calculated and compared for myxoid and nonmyxoid tumors and for benign and malignant tumors.ResultsThe ADC (mean ± SD) was 1.92 ± 0.41 × 10–3 mm2/second in myxoid containing tumors, whereas the ADC was 0.97 ± 0.33 × 10–3 mm2/second in nonmyxoid tumors. The ADCs of the myxoid and nonmyxoid tumors were significantly different (P < 0.01). The ADCs were 1.45 ± 0.59 × 10–3 mm2/second in malignant tumors and 1.50 ± 0.64 × 10–3 mm2/second in benign tumors. The ADCs of benign and malignant soft‐tissue tumors were not significantly different.ConclusionThe ADCs of myxoid‐containing soft‐tissue tumors were significantly higher than those of nonmyxoid soft‐tissue tumors. The myxoid matrix influences ADCs of both benign and malignant soft‐tissue tumors. J. Magn. Reson. Imaging 2007;25:1199–1204. © 2007 Wiley‐Liss, Inc.
Investigation of coil phase compensation in 3D imaging at very high acceleration factors
Authors: McDougall Mary Preston , Wright Steven M. 
Published: May 2007

AbstractPurposeTo investigate the confounding effect of the coil phase in highly accelerated parallel imaging with small coils, contextualize the effect in terms of single‐echo acquisition (SEA) imaging, and show that it can be managed in the case of 3D imaging.Materials and MethodsThe effects of the coil phase variations in a 64‐channel array of surface microcoils were modeled. Fully encoded 64 × 128 × 64 (Nphase enc×Nreadout×Nslice enc) 3D data sets were obtained, from which factor of 64 accelerated 3D image sets (1 × 128 × 64 each) were extracted from single phase‐encoding lines, each representing a different phase compensation value.ResultsA comparison of the SEA images indicates that the choice of a compromise value for phase compensation successfully enabled a straightforward extension of SEA imaging to three dimensions. The use of the single compromise compensation value in the 3D acquisition resulted in a signal‐to‐noise ratio (SNR) penalty ranging from 6% to 41% through the slab when compared to the highest SNR possible using any phase compensation value.ConclusionThe coil‐related phase shift issues inherent to highly accelerated imaging will require further study, but this work indicates the general nature of the problem and, more auspiciously, shows that it can be mitigated for at least this application. J. Magn. Reson. Imaging 2007;25:1305–1311. © 2007 Wiley‐Liss, Inc.
Creatine treatment promotes differentiation of GABA‐ergic neuronal precursors in cultured fetal rat spinal cord
Authors: Ducray Angélique D. , Schläppi Janine‐Ai , Qualls Rachel , Andres Robert H. , Seiler Rolf W. , Schlattner Uwe , Wallimann Theo , Widmer Hans Rudolf 
Published: May 2007

AbstractCreatine is a substrate of cytosolic and mitochondrial creatine kinases. Its supplementation augments cellular levels of creatine and phosphocreatine, the rate of ATP resynthesis, and improves the function of the creatine kinase energy shuttle. High cytoplasmatic total creatine levels have been reported to be neuroprotective by inhibiting apoptosis. In addition, creatine has direct antioxidant effects, which may be of importance in amyotrophic lateral sclerosis. In the present study, we investigated the effects of creatine [5 mM] on survival and differentiation of cultured GABA‐immunoreactive (‐ir) and choline acetyltransferase (ChAT)‐ir rat spinal cord neurons. Furthermore, we addressed the neuroprotective potential of creatine supplementation against 3‐nitropropionic acid (3‐NP) induced toxicity. General cell survival and total neuronal cell density were not altered by chronic creatine treatment. We found, however, after chronic creatine and short‐term creatine exposure a significantly higher density of GABA‐ir neurons hinting to a differentiation‐inducing mechanism of creatine. This notion is further supported by a significant higher content of GAD after creatine exposure. Creatine supplementation also exerted a partial, but significant neuroprotection for GABA‐ir neurons against 3‐NP induced toxicity. Interestingly, chronic creatine treatment did not alter cell density of ChAT‐ir neurons but promoted their morphologic differentiation. Cell soma size and number of primary neurites per neuron were increased significantly after creatine supplementation. Taken together, creatine supplementation promoted the differentiation or the survival of GABAergic neurons and resulted in partial neuroprotection against 3‐NP induced toxicity. The data suggest that creatine may play a critical role during development of spinal cord neurons. © 2007 Wiley‐Liss, Inc.
Enhanced accumulation of phosphorylated α‐synuclein in double transgenic mice expressing mutant β‐amyloid precursor protein and presenilin‐1
Authors: Kurata Tomoko , Kawarabayashi Takeshi , Murakami Tetsuro , Miyazaki Kazunori , Morimoto Nobutoshi , Ohta Yasuyuki , Takehisa Yasushi , Nagai Makiko , Ikeda Masaki , Matsubara Etsuro , Westaway David , Hyslop Peter St. George , Harigaya Yasuo , Kamiya Tatsushi , Shoji Mikio , Abe Koji 
Published: May 2007

AbstractA recent report showed that the accumulation of α‐synuclein (α‐syn) was detected in the brains of one‐third of Alzheimer's disease and Down syndrome patients. However, the relationship between amyloid‐β protein (Aβ) and α‐syn remains unclear. We analyzed the relation between the mutation of presenilin‐1 (PS‐1) and the pathological features of β‐amyloidosis and α‐synucleinopathy. We generated doubly transgenic mice overexpressing mutant β‐amyloid precursor protein (βAPP; Tg2576) and mutant PS‐1 (PS1L286Vtg; line 198) and analyzed 19 double Tg βAPP+/PS+ mice at 5–23 months (young to old), 23 age‐matched single Tg βAPP+/PS− mice, and 11 non‐Tg littermates. Immunohistochemical comparison was performed in these three groups by counting the area and the number of α‐syn‐ or phosphorylated α‐syn (pα‐syn)‐positive dystrophic neurites per plaque (ASPDN, pASPDN). The acceleration of Aβ pathology was found with earlier onset and exaggerated numbers in double Tg βAPP+/PS+ compared with single Tg βAPP+/PS− mouse brains. The accumulation of ASPDN and pASPDN was also accelerated in double Tg βAPP+/PS+ compared with single Tg βAPP+/PS− mouse brains, especially in pASPDN. The number and area of α‐syn and pα‐syn, and the ratio of pα‐syn positive neurites were significantly higher in double Tg βAPP+/PS+ than in single Tg βAPP+/PS− mouse brains in middle‐aged and old groups. Additional overexpression of mutant PS‐1 accelerated Aβ‐induced α‐synucleinopathy and further facilitated the phosphorylation of α‐syn, suggesting a direct association between mutant PS‐1 and phosphorylation of α‐syn. © 2007 Wiley‐Liss, Inc.
Dynamics of lactate concentration and blood oxygen level‐dependent effect in the human visual cortex during repeated identical stimuli
Authors: Mangia Silvia , Tkác̆ Ivan , Logothetis Nikos K. , Gruetter Rolf , Van de Moortele Pierre‐Francois , Uğurbil Kâmil 
Published: May 2007

AbstractIn vivo 1H NMR spectroscopy at 7 T was utilized to measure the changes in lactate concentration upon repeated identical visual stimuli, each lasting for 2 min. The average amplitude of these increases was found to be reduced over time (P < 0.01), from 0.13 ± 0.02 μmol/g during the first half of the stimulation paradigm, to 0.06 ± 0.02 μmol/g during the second half of the stimulation paradigm. In contrast, the blood oxygen level‐dependent (BOLD) effect on the fMRI water signal and on the height of the total creatine signal at 3.03 ppm was persistent during the whole observation period. This finding may suggest a differential adaptation of cortical output that is not reflected at the level of the global excitation‐inhibition activity of the cortical canonical circuits. Alternative possibilities that could account for an adaptation of [Lac] changes are also discussed. © 2007 Wiley‐Liss, Inc.
Rho‐kinase activation in endothelial cells contributes to expansion of infarction after focal cerebral ischemia
Authors: Yagita Yoshiki , Kitagawa Kazuo , Sasaki Tsutomu , Terasaki Yasukazu , Todo Kenichi , Omura‐Matsuoka Emi , Kaibuchi Kozo , Hori Masatsugu 
Published: May 2007

AbstractMicrocirculatory disturbances contribute to the expansion of infarct lesions after focal cerebral ischemia. Recently, it was shown that Rho‐kinase involves in endothelial dysfunction via down‐regulation of endothelial nitric oxide synthase function in a rodent stroke model. However, it is not clear whether endothelial Rho‐kinase is activated in vivo or Rho‐kinase activation contributes to microcirculatory disturbances after cerebral ischemia. In this study, we assessed the temporal and spatial profiles of Rho‐kianse activity and the effect of the Rho‐kinase inhibitor fasudil on microcirculatory disturbances in the focal brain ischemia. Rho‐kinase activation was evaluated by analyzing the phosphorylation of adducin, a substrate of Rho‐kinase, by immunohistochemistry. Staining for p‐adducin was found in endothelia in the ischemic area 6 hr after induction of ischemia. Microcirculatory disturbances and increased endothelial cell staining for von Willebrand factor (vWF) were observed in the same area. Postischemic treatment with fasudil suppressed endothelial Rho‐kinase activation, preserved microcirculation, and inhibited endothelial cell vWF staining. These effects resulted in inhibition of infarct expansion and improvement of neurologic deficits. These findings indicate that Rho‐kinase is activated in the endothelial cells and contributes to microcirculatory disturbances in cerebral ischemia. The vascular protective effect of Rho‐kinase inhibitors may be useful in the treatment of the acute phase of ischemic stroke. © 2007 Wiley‐Liss, Inc.
Aquaporin 9 changes in pyramidal cells before and is expressed in astrocytes after delayed neuronal death in the ischemic hippocampal CA1 region of the gerbil
Authors: Hwang In Koo , Yoo Ki‐Yeon , Li Hua , Lee Bong‐Hee , Suh Hong‐Won , Kwon Young‐Guen , Won Moo Ho 
Published: May 2007

AbstractIn the present study, we observed changes of aquaporin 9 (AQP9) in the hippocampus induced by 5 min of ischemia in gerbils. In sham‐operated animals, weak AQP9 immunoreactivity was detected in the stratum pyramidale of the hippocampus. AQP9 immunoreactivity, and its protein level in the CA1 region began to increase significantly at 6 hr and peaked 24 hr after ischemia. In the CA2/3 region, AQP9 immunoreactivity significantly increased at 12 hr after ischemia. Thereafter, AQP9 immunoreactivity in the hippocampus decreased continuously with time. From 4 days after ischemia, AQP9 immunoreactivity in the CA1 region was expressed and increased in glial components in the strata oriens and radiatum. Based on double‐immunofluorescence staining, many AQP9‐immunoreactive glial cells in the CA1 region were identified as astrocytes. In a reverse transcription‐polymerase chain reaction study, AQP9 mRNA levels significantly increased in the CA1 region at 6 hr after ischemia, and thereafter AQP9 mRNA levels decreased with time after ischemia. In addition, the water content in the gerbil hippocampus was highest 3 hr after ischemia/reperfusion; thereafter, water content in the ischemic hippocampus was higher than that in the sham‐operated group. This result shows how AQP9 in the gerbil hippocampus changes in neurons and is expressed in astrocytes before and after delayed neuronal death, respectively, after ischemia. These results indicate that changes in AQP9 in ischemic CA1 pyramidal cells may be related to delayed neuronal death and that the expression of AQP9 in astrocytes is related to gliosis in the CA1 region after transient forebrain ischemia. © 2007 Wiley‐Liss, Inc.
Cell cycle dependent phosphatase activity in Bacillus subtilis
Authors: Sandler Naomi , Keynan Alex 
Published: May 2007

AbstractIn Bacillus subtilis there is evidence that the replication origin of the DNA molecule is attached to the cytoplasmic membrane, and that this attachment is essential for the initiation of replication. We have previously shown that attachment of DNA to the membrane is cyclic and that DNA becomes attached to the cytoplasmic membrane at the beginning of replication and is subsequently released. We have also shown that membrane protein phosphorylation is associated with the initiation of DNA replication in B. subtilis. We now report that cantharidin, an inhibitor of eukaryotic serine/threonine protein phosphatases type 1 and 2A, stimulated membrane binding of DNA and caused premature initiation of DNA replication in B. subtilis cells. The membrane of B. subtilis cells had cell cycle dependent phosphatase activity against a standard substrate in vitro. Cloning of the B. subtilis protein PrpE and production of antibodies allowed us to identify the protein in the cytoplasmic membrane. Its presence was cell cycle dependent, and appeared to contribute to the observed phosphatase activity. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Molecular characterization of the non‐coding promoter and leader regions and full‐length 16S ribosomal RNA (rRNA) gene of Taylorella asinigenitalis
Authors: Tazumi A. , Saito S. , Sekizuka T. , Murayama O. , Moore J.E. , Millar B.C. , Matsuda M. 
Published: May 2007

AbstractThe 3,339 base pair (bp) sequences encoding a putative open reading frame (ORF), non‐coding promoter and leader regions (approximately 320 bp), full‐length 16S ribosomal RNA (rRNA) gene (approximate 1,540 bp) and part of the 16S–23S rDNA internal spacer region (ISR) were determined from genome DNA libraries of the Taylorella asinigenitalis (UK‐1) isolate. The non‐coding promoter and leader regions included antiterminators (boxB, boxA and boxC) immediately upstream of the 16S rRNA gene sequence. An approximately 680 bp region upstream of the non‐coding promoter region appears to contain a putative ORF with high sequence similarity to GTP cyclohydrolase I. In addition, a typical order of intercistronic tRNA genes with the 48 nucleotide spacer of 5′‐16S rDNA‐tRNAIle‐tRNAAla‐23S rDNA‐3′ was demonstrated in a part of the 16S–23S rDNA ISR. The antiterminators of boxB and boxA were also identified in the ISR.A phylogenetic analysis based on the 16S rRNA gene sequence information clearly demonstrated that the five T. asinigenitalis isolates formed a cluster together with the three T. equigenitalis strains, more similar to Pelistega europaea than the other β‐Proteobacteria from the 13 species of 11 genera. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Antimicrobial mechanisms of ortho ‐phthalaldehyde action
Authors: Simões Manuel , Simões Lúcia C. , Cleto Sara , Machado Idalina , Pereira Maria O. , Vieira Maria J. 
Published: May 2007

AbstractBiocides generally have multiple biochemical targets. Such a feature easily entangles the analysis of the mechanisms of antimicrobial action. In this study, the action of the dialdehyde biocide ortho ‐phtalaldehyde (OPA), on bacteria, was investigated using the Gram‐negative Pseudomonas fluorescens. The targets of the biocide action were studied using different bacterial physiological indices. The respiratory activity, membrane permeabilization, physico‐chemical characterization of the bacterial surfaces, outer membrane proteins (OMP) expression, concomitant influence of pH, contact time and presence of bovine serum albumin (BSA) on respiratory activity, morphological changes and OPA‐DNA interactions were assessed for different OPA concentrations.With the process conditions used, the minimum inhibitory concentration was 1500 mg/l, the concentration to promote total loss of bacterial culturability was 65 mg/l and the concentration needed to inactivate respiratory activity was 80 mg/l. These data are evidence that culturability and respiratory activity were markedly affected by the biocide. OPA lead, moreover, to a significant change in cell surface hydrophobicity and induced propidium iodide uptake. Such results suggest cytoplasmic membrane damage, although no release of ATP was detected. At pH 5, the bactericidal action of OPA was stronger, though not influenced by BSA presence. Nevertheless, at pH 9, BSA noticeably (p < 0.05) impaired biocide action. A time‐dependent effect in OPA action was evident when contemplating respiratory activity variation, mainly for the lower exposure times. Scanning electron microscopy allowed to detect bacterial morphological changes, translated on cellular elongation, for OPA concentrations higher than 100 mg/l. Interferences at DNA level were, however, restricted to extreme biocide concentrations. The overall bactericidal events occurred without detectable OMP expression changes.In conclusion, the results indicated a sequence of events responsible for the antimicrobial action of OPA: it binds to membrane receptors due to cross‐linkage; impairs the membrane functions allowing the biocide to enter through the permeabilized membrane; it interacts with intracellular reactive molecules, such as RNA, compromising the growth cycle of the cells and, at last, with DNA. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Production, purification, and characterization of a novel galactose oxidase from Fusarium acuminatum
Authors: Alberton Dayane , Silva de Oliveira Luciana , Peralta Rosane Marina , Barbosa‐Tessmann Ione Parra 
Published: May 2007

AbstractExtra‐cellular production of a novel galactose oxidase from Fusarium acuminatum using submerged fermentation was studied. Glucose (1.0% w/v) was used as the sole carbon source. Maximum galactose oxidase production (approximately 4.0 U/ml) was obtained when fermentation was carried out at 25 °C, with orbital shaking (100 rpm) and an initial medium of pH 7.0, for 96 h, using a 2% (v/v) inoculum made from a homogenized four‐day‐old liquid culture, in the presence of copper, manganese, and magnesium. The enzyme was purified by one‐step affinity chromatography, with a recovery of 42% of the initial activity. The purified enzyme ran as a single band of 66 kDa in SDS‐PAGE. Optimal pH and temperature for the enzyme activity were 8.0 and 30 °C, respectively. The enzyme was thermoinactivated at temperatures above 60 °C. The purified enzyme was active toward various substrates, including galactose, dihydroxyacetone, guar gum, lactose, melibiose, methyl‐galactopyranoside, and raffinose. SDS was an inhibitor but EDTA, Tween 80, NH4+, Na+, Mg2+, K+, and glycerol were not. The Michaelis‐Menten constant (Km) for galactose was estimated to be 16.2 mM, while maximal velocity (Vmax) was 0.27 μmol of H2O2 · ml–1 · min–1. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Conformational equilibria in dihaloheptasilanes X2Si[SiMe(SiMe3)2]2 with X = F, Cl, Br, I: A Raman spectroscopic and quantum chemical DFT study
Authors: Dzambaski A. , Flock M. , Hassler K. 
Published: May 2007

AbstractEquilibrium geometries, stabilities and vibrational wavenumbers for conformers of the dihaloheptasilanes X2Si[SiMe(SiMe3)2]2 with X = F, Cl, Br and I were calculated at the density functional B3LYP level employing 6‐311G(d) basis sets and SDD pseudopotentials for Br and I. Two spectroscopically distinct low‐energy conformers were located for all four heptasilanes with energy differences of 5.5, 4.7, 1.9 and 1.2 kJ mol−1 for X = F, Cl, Br and I, respectively. Five more conformers were found for difluoroheptasilane and four for X = Cl, Br and I. They all have relative energies larger than 7.5 and up to 17 kJ mol−1 and are negligibly populated at room temperature. Variable temperature solution Raman spectra (−70 to + 100 °C) in a wavenumber range typical for SiSi stretching vibrations (280‐350 cm−1) confirm these results. For X = Br and I, no temperature effects at all could be observed as a very rapid inter‐conversion between the two low‐energy conformers, which is fast even on the time scale of Raman spectroscopy, occurs. For X = Cl, rapid inter‐conversion also occurs, and a third conformer could be detected at higher temperatures (50–100 °C). For X = F, intensity changes with temperature are consistent with the presence of two low‐energy conformers. Copyright © 2007 John Wiley & Sons, Ltd.
Vietnam veteran levels of combat: Related to later violence?
Authors: Calvert William E. , Hutchinson Roger L. 
Published: May 2007

AbstractThe purpose of this study was to investigate whether or not a relationship exists between levels of combat experienced by Vietnam veterans and later perceptions of violence, violent attitudes, or violent behavior. Comparison groups included (1) heavy combat Vietnam veterans, (2) light combat Vietnam veterans, (3) Vietnam era veterans, and (4) nonveterans (civilians). Based upon the results of this study, levels of combat appear to be unrelated to postwar violent attitudes. Also, neither heavy nor light combat Vietnam veterans appear to engage in violent behavior any more than their Vietnam era veteran or civilian peers.