bluuebunny/crossref_metadata_2025_split huggingface dataset:
Proliferating resident microglia express the stem cell antigen CD34 in response to acute neural injury
Authors: Ladeby Rune , Wirenfeldt Martin , Dalmau Ishar , Gregersen Rikke , García‐Ovejero Daniel , Babcock Alicia , Owens Trevor , Finsen Bente 
Published: January 2005

AbstractReactive microgliosis is a highly characteristic response to neural injury and disease, which may influence neurodegenerative processes and neural plasticity. We have investigated the origin and characteristics of reactive microglia in the acute phase of their activation in the dentate gyrus following transection of the entorhino‐dentate perforant path projection. To investigate the possible link between microglia and hematopoietic precursors, we analyzed the expression of the stem cell marker CD34 by lesion‐reactive microglia in conjunction with the proliferation marker bromodeoxyuridine (BrdU) and the use of radiation bone marrow (BM) chimeric mice. We found that CD34 is upregulated on early‐activated resident microglia, rather than by infiltrating bone marrow‐derived cells. The number of CD34+ microglia peaked at day 3 when 67% of the resident CD11b/Mac‐1+ microglia co‐expressed CD34, and all CD34+ cells co‐expressed Mac‐1, and decreased sharply toward day 5, unlike Mac‐1, which was maximally expressed at day 5. Approximately 80% of the CD34+ cells in the denervated dentate gyrus had incorporated BrdU into their nuclei at day 3. We also showed that CD34 is upregulated on early‐activated microglia in the facial motor nucleus following peripheral axotomy. The results suggest lesion‐reactive microglia to consist of functionally distinct subpopulations of cells; a major population of activated resident CD34+Mac‐1+ microglia with a high capacity for self‐renewal, and a subpopulation of CD34−Mac‐1+ microglia which has a mixed extrinsic and intrinsic origin and whose proliferative capacity is unknown. © 2005 Wiley‐Liss, Inc.
Glial restricted precursors protect against chronic glutamate neurotoxicity of motor neurons in vitro
Authors: Maragakis Nicholas J. , Rao Mahendra S. , Llado Jeronia , Wong Victor , Xue Haipeng , Pardo Andrea , Herring Joseph , Kerr Douglas , Coccia Carol , Rothstein Jeffrey D. 
Published: January 2005

AbstractWe have examined the expression of glutamate transporters in primary and immortalized glial precursors (GRIPs). We subsequently transduced these cells with the GLT1 glutamate transporter and examined the ability of these cells to protect motor neurons in an organotypic spinal cord culture. We show that glial restricted precursors and GRIP‐derived astrocytes predominantly express glutamate transporters GLAST and GLT1. Oligodendrocyte differentiation of GRIPs results in downregulation of all glutamate transporter subtypes. Having identified these precursor cells as potential vectors for delivering glutamate transporters to regions of interest, we engineered a line of GRIPS that overexpress the glutamate transporter GLT1. These cells (G3 cells) have a nearly fourfold increase in glutamate transporter expression and at least a twofold increase in the Vmax for glutamate transport. To assess whether G3 seeding can protect motor neurons from chronic glutamate neurotoxicity, G3s were seeded onto rat organotypic spinal cord cultures. These cultures have previously been used extensively to understand pathways involved in chronic glutamate neurotoxicity of motor neurons. After G3 seeding, cells integrated into the culture slice and resulted in levels of glutamate transport sufficient to enhance total glutamate uptake. To test whether neuroprotection was related to glutamate transporter overexpression, we isolated GRIPS from the GLT1 null mouse to serve as controls. The seeding of G3s resulted in a reduction of motor neuron cell death. Hence, we believe that these cells may potentially play a role in cell‐based neuroprotection from glutamate excitotoxicity. © 2005 Wiley‐Liss, Inc.
New benzylpiperazine derivatives bearing mono‐ and bis‐dialkyl substituted 1,2,4‐triazoles
Authors: Al‐Soud Yaseen A. , Qalalweh Mohammed N. A. , Al‐Sa'doni Haitham H. , Al‐Masoudi Najim A. 
Published: January 2005

AbstractCycloaddition of the 1‐aza‐2‐azoniaallenes 3 with p‐cyanobenzyl chlorides afforded, after spontaneous rearrangement, the 1,5‐dialkyl‐3‐[4‐chloromethyl)phenyl]‐1H‐[1,2,4]‐triazoles 6. A series of 1,5‐dialkyl‐1H‐[1,2,4]‐triazol‐3‐yl)benzyl‐piperazines 7 and 8 were prepared from direct condensation of 6 with piperazine and N‐methylpiperazine, respectively. The structures of the newly synthesized products were identified by 2D NMR spectroscopy. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:28–32, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20061
Mildly and highly selective reductive deoxygenation of para‐di‐ and monoalkylaminophenyl ketones by borane
Authors: Wei Tiezheng , Lan Yu , Xu Jiaxi 
Published: January 2005

AbstractPara‐di‐ and monoalkylaminophenyl ketones were reduced selectively to para‐alkyl N,N‐di‐ and N‐monoalkylanilines in good to excellent yields by borane under mild, convenient, and neutral conditions. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:2–5, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20062
Synthetic studies using unsaturated and active phosphonium salts. A convenient preparation of furano‐ and pyrano[2,3‐c]pyridazines and substituted quinolines
Authors: Abdou Wafaa M. , Ganoub Neven A. , Fahmy Amin F. , Shaddy Abeer M. 
Published: January 2005

AbstractBy applying vinyl‐ (3) and allyltriphenylphosphonium bromides (9) to 4‐cyano‐5,6‐difur‐2′yl‐2H‐pyridazin‐3‐one (1) the corresponding fused 5,8‐oxazolo‐ 6, 12 (∼37%) and pyrano‐ 8, 13, 14 (∼20%) derivatives are isolated whereas with alkylphosphonium bromides 15a,b fused furans 17a,b (22%) and isopyrroles 18a,b (∼45%) are obtained. On the other hand, the reaction of 2‐[(benzylidene)amino]‐benzonitrile (2) with 3 and 9 yielded benzoazepines 20 and 21 (∼56%). With 15a,b, quinolines 23a,b (∼46%) and quinazoline 25 (∼24%) are obtained. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:56–64, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20065
Bis(trimethylsilyl)diazene revisited. Density functional theory (DFT) calculations of nitrogen NMR parameters of some azo‐compounds
Authors: Wrackmeyer Bernd , Köhler Christian 
Published: January 2005

AbstractCalculations of nitrogen NMR parameters [chemical shifts δN and indirect nuclear spin–spin coupling constants J(N,N), J(N,13C), J(29Si,N)] of noncyclic azo‐compounds R1NNR2 (R1, R2 = H, Me, Ph, SiH3, SiMe3) and cyclic azo‐compounds [NNCH2, NN(CH2)3 NN(CH2)2SiH2, and NN(SiH2CH2SiH2)] by density functional theory (DFT) methods [B3LYP/6‐311+G(d,p) level of theory] provide data in reasonable agreement with experimental values. The influence of cis‐ and trans‐geometry is reflected by the calculations, and amino‐nitrenes are also included for comparison. The spin–spin coupling constants are analyzed with respect to contact (Fermi contact term, FC) and non‐ contact contributions (paramagnetic and diamagnetic spin‐orbital terms, PSO and DSO, and spin‐dipole term, SD). Bis(trimethylsilyl)diazene 6a can be generated by an alternative method, using the reaction of bis(trimethylsilyl)sulfur diimide with bis‐ (trimethylsilyl)amino‐trimethylsilylimino‐phosphane. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:84–91, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20075
Effects on proliferation and melanogenesis by inhibition of mutant BRAF and expression of wild‐type INK4A in melanoma cells
Authors: Rotolo Sabrina , Diotti Raffaella , Gordon Ronald E. , Qiao Rui F. , Yao Zhong , Phelps Robert G. , Dong Jianli 
Published: January 2005

AbstractActivating BRAF mutations and loss of wild‐type INK4A expression both occur at high frequencies in melanomas. Here, we present evidence that BRAF and INK4A have different effects on melanogenesis, a marker of melanocytic differentiation. Human melanoma cell line 624Mel harbors mutations in both BRAF and INK4A. The in vitro and in vivo growth of these cells was inhibited by either reduced expression of mutant BRAF using stable retroviral RNA interference (RNAi) or retrovirus‐mediated stable expression of wild‐type INK4A cDNA. Consistent with the observed growth inhibition, phosphorylation of S780 and S795 in pRB, both CDK4/6 targets, was suppressed in cells expressing either mutant BRAF RNAi or wild‐type INK4A. Interestingly, melanoma cells expressing mutant BRAF RNAi had increased pigmentation, produced more mature melanosomes and melanin and expressed higher levels of tyrosinase and tyrosinase‐related protein‐1, whereas melanogenesis was not induced by wild‐type INK4A. We found that the melanocyte lineage‐specific master control protein microphthalmia‐associated transcription factor was upregulated by inhibition of mutant BRAF, which may be the cause for the melanogenic effect of BRAF RNAi. The results suggest that, although both BRAF and INK4A lesions promote cell growth and tumor formation, mutant BRAF may also induce dedifferentiation in melanoma cells. © 2005 Wiley‐Liss, Inc.
Small fiber diameter fibro‐porous meshes: Tissue response sensitivity to fiber spacing
Authors: Sanders J. E. , Lamont S. E. , Mitchell S. B. , Malcolm S. G. 
Published: January 2005

AbstractThe purpose of this research was to determine if fiber spacing for small fiber diameter fibro‐porous meshes affected tissue response in vivo. Disk‐shaped polyurethane meshes, with mean fiber diameters of 7.6 μm and fiber spacing between 6 and 68 μm, were implanted in rat subcutaneous dorsum for 5‐week intervals and then prepared for light microscopy and morphological analysis. Results showed that implants with 12‐ to 68‐μm spacing had no histologically apparent fibrous capsule around the perimeter, a result different from that for 6‐μm spacing samples that had a capsule around a mean of 34.2% of the perimeter. For the 12‐ to 68‐μm spacing range, a mean of 21.0% of individual fibers within the meshes were encapsulated. Qualitatively, it appeared that larger fibers were encapsulated more frequently than smaller ones. When nodeless or baggy meshes were implanted, cells tended to cluster three or more fibers into groups and then encapsulate each group. Over the 6‐ to 68‐μm spacing range, cell nuclei volume fraction within the meshes increased from the 6‐ to the 29‐μm spacing (p = 0.000) and then decreased from the 29‐ to the 68‐μm spacing (p = 0.015). There was a trend of an increase in local vessel volume fraction with spacing over the 6‐ to 68‐μm range, though the relationship was weak. The results indicate that the reason for the lack of encapsulation of small‐fiber fibro‐porous meshes is not exclusively a pore boundary explanation, as is proposed for small‐pore porous meshes. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res 72A: 335–342, 2005
Effect of varied release kinetics of the osteogenic thrombin peptide TP508 from biodegradable, polymeric scaffolds on bone formation in vivo
Authors: Hedberg Elizabeth L. , Kroese‐Deutman Henriette C. , Shih Charles K. , Crowther Roger S. , Carney Darrell H. , Mikos Antonios G. , Jansen John A. 
Published: January 2005

AbstractThis study was designed to assess the influence of varied release kinetics of the osteogenic thrombin peptide TP508 from osteoconductive poly(propylene fumarate)‐based (PPF) composite scaffolds on bone formation in vivo. Four classes of scaffolds were constructed with different TP508 dosages (200, 100, or 0 μg) and release kinetics (large burst release, minimal burst release, or no release) and implanted in 15.0 mm segmental defects in rabbit radii. The animals were euthanized at 12 weeks and the implants were analyzed by light microscopy, histological scoring analysis, and histomorphometric analysis. Samples from all classes displayed bone growth within the pores of the scaffold near the edges of the defect. In areas where bone was not observed, the pores were filled with mostly fibrous tissue and exhibited minimal inflammatory response for all classes. In contrast to other scaffold classes, scaffolds containing a total dose of 200 μg TP508 and exhibiting a large burst release profile showed statistically more bone formation guided along the surface of the scaffold, with these scaffolds averaging 80% of the defect length bridged with bone compared to 10% or less bridged for the other scaffold classes. These results demonstrate that the extent of in vivo bone formation in response to controlled release from PPF‐composite scaffolds is determined by the release kinetics of the incorporated osteogenic peptide. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res 72A: 343–353, 2005
Disparity of activation onset in sensory cortex from simultaneous auditory and visual stimulation: Differences between perfusion and blood oxygenation level‐dependent functional magnetic resonance imaging
Authors: Liu Ho‐Ling , Feng Ching‐Mei , Li Jinqi , Su Fan‐Chi , Li Ning , Glahn David , Gao Jia‐Hong 
Published: January 2005

AbstractPurposeTo compare the temporal behaviors of perfusion and blood oxygenation level‐dependent (BOLD) functional magnetic resonance imaging (fMRI) in the detection of timing differences between distinct brain areas, and determine potential latency differences between stimulus onset and measurable fMRI signal in sensory cortices.Materials and MethodsInversion recovery (IR) spin‐echo echo‐planar imaging (EPI) and T2*‐weighted gradient‐echo EPI sequences were used for perfusion‐ and BOLD‐weighted experiments, respectively. Simultaneous auditory and visual stimulations were employed in an event‐related (ER) paradigm. Signal time courses were averaged across 40 repeated trials to evaluate the onset of activation and to determine potential differences of activation latency between auditory and visual cortices and between these scanning methods.ResultsTemporal differences between visual and auditory areas ranged from 90–200 msec (root‐mean‐square (RMS) = 134 msec) and from –80 to 930 msec (RMS = 604 msec) in perfusion and BOLD measurements, respectively. The temporal variability detected with BOLD sequences was larger between subjects and was significantly greater than that in the perfusion response (P < 0.04). The measured time to half maximum (TTHM) values for perfusion imaging (visual, 3260 ± 710 msec; auditory, 3130 ± 700 msec) were earlier than those in BOLD responses (visual, 3770 ± 430 msec; auditory, 3360 ± 460 msec).ConclusionThe greater temporal variability between brain areas detected with BOLD could result from differences in the venous contributions to the signal. The results suggest that perfusion methods may provide more accurate timing information of neuronal activities than BOLD‐based imaging. J. Magn. Reson. Imaging 2005;21:111–117. © 2005 Wiley‐Liss, Inc.
Assessing adenoviral hammerhead ribozyme and small hairpin RNA cassettes in neurons: Inhibition of endogenous caspase‐3 activity and protection from apoptotic cell death
Authors: Bantounas Ioannis , Glover Colin P.J. , Kelly Stephen , Iseki Sachiko , Phylactou Leonidas A. , Uney James B. 
Published: January 2005

AbstractAntisense technology, including ribozyme and small interfering RNA, is being developed to mediate the down‐regulation of specific intracellular genes. It was observed in this study that both antiluciferase ribozymes and short hairpin RNAs (shRNAs) could significantly reduce the activity of exogenously expressed luciferase in primary hippocampal neurons in a viral titer‐dependent manner. shRNAs were more effective gene‐silencing agents than ribozymes, although they exhibited some nonspecific gene‐silencing effects at high viral titers. We also attempted to increase ribozyme efficacy by using a woodchuck hepatitis posttranscriptional regulatory element (WPRE) in the ribozyme expression cassette. The results showed that adenoviral vectors encoding specific ribozymes could silence the cellular expression of luciferase and endogenous procaspase‐3 significantly. Furthermore, the antiprocaspase‐3 ribozyme was shown to inhibit staurosporine‐mediated cell death. The addition of a WPRE did not, however, increase or decrease ribozyme activity. As far as we are aware, this is the first example of adenovirally mediated delivery of hammerhead ribozymes being used to manipulate gene expression in primary neurons. The results therefore suggest that hammerhead ribozymes may be useful tools for studying neuronal gene function and have potential as therapeutic agents to treat CNS diseases. © 2005 Wiley‐Liss, Inc.
Identification of rat Gas7 isoforms differentially expressed in brain and regulated following kainate‐induced neuronal injury
Authors: Chang P.‐Y. , Kuo J.‐T. , Lin‐Chao Sue , Chao Chuck C.‐K. 
Published: January 2005

AbstractThe growth arrest‐specific gene 7 (Gas7) is expressed primarily in the brain and is necessary for the formation of neurite in cultured cerebellar preneurons. The endogenous rat Gas7 (rGas7) is transiently elevated before nerve growth factor‐promoted neurite outgrowths emerge in cultured PC12 cells. We report three Gas7 isoforms (a, b, and c) in rat tissues. Peptide microsequencing identified two Gas7 forms, rGas7‐a (38 kDa) and rGas7‐b (47 kDa). rGas7‐c can be predicted from a transcription variant by alternative splicing. Although two open reading frames were predicted, a cloned rGas7 cDNA encoded mostly rGas7‐a in mammalian cells. The overexpression of the rGas7 cDNA in PC12 cells sufficed to promote small lamellipodia‐ and filopodia‐like cell processes that resemble the initial stages of neurite formation. Three rGas7 isoforms were differentially expressed in all of the brain subregions. Only rGas7‐a was detected in rat cerebellum, as in mouse cerebellum. Kainate injury did not affect the level of rGas7‐b, but the level of isoform c was substantially suppressed in the hippocampus. Immunohistochemistry reveals that Gas7 was expressed primarily in the pyramidal neurons of the hippocampus and was quickly attenuated before recovery in the CA3 area after kainate was administered. These results suggest that differential expression and unique regulation of Gas7 isoforms in brain subregions may be important in specialized brain functions. Conservation of Gas7 isoforms by alternative splicing in mammals is also considered. © 2005 Wiley‐Liss, Inc.
Experimental and computational studies of the thermal decomposition of halon 1211
Authors: Yu Hai , Kennedy Eric M. , Uddin Md. Azhar , Sullivan Simon P. , Dlugogorski Bogdan Z. 
Published: January 2005

AbstractThermal pyrolysis of halon 1211 (CBrClF2), diluted in nitrogen, in a tubular alumina reactor, has been studied over the temperature range of 773–1073 K at residence times from 0.3 to 2 s. At temperatures below 973 K, the major products were CCl2F2, CBr2F2, C2Cl2F4, C2BrClF4, C2F4, and C2Br2F4. Further increasing temperature resulted in the formation of CBrF3, CClF3, and many other species whose formation necessitated the rupture of CF bonds. Coke formation was also observed on the surface of the reactor at high temperatures. A kinetic reaction scheme involving 16 species and 25 reaction steps was developed and applied to model the thermal pyrolysis of halon 1211 over the temperature range of 773–973 K. Sensitivity analysis suggests that the reaction CBrClF2 + CClF2→CCl2F2 + CBrF2 constitutes the major pathway for the decomposition of halon 1211 under the conditions investigated. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 134–146, 2005
Effects of mixed H2O‐CH3CN solvents on the rate of hydrazinolysis of N‐phenylphthalimide: Spectral and kinetic evidence for the occurrence of N‐aminophthalimide on the reaction path
Authors: Ariffin Azhar , Leng Sim Yoke , Lan Lai Chwee , Khan M. Niyaz 
Published: January 2005

AbstractKinetic study on the cleavage of N‐phenylphthalimide (NPhPT) in the presence of 0.05 M NH2NH2 and mixed H2O‐CH3CN solvents reveals the occurrence of reaction scheme

equation image

where A, B, C, C1, An, E, and F represent NPhPT, o‐CO−2C6H4CONHC6H5, o‐CONHNH2C6H4‐ CONHC6H5, N‐aminophthalimide, aniline, o‐CO−2C6H4CONHNH2, and o‐CONHNH2C6H4‐CONHNH2, respectively. But, in the presence of either nonbuffered ⩾0.20 M NH2NH2 hydrazine buffer of pH ∼7.30–8.26 with total buffer concentration ([Buf]T) of >0.02 M, further conversion of F to 2,3‐dihydrophthalazine‐1,4‐dione (DHPD) has been detected depending upon the length of the reaction time (t), the values of [Buf]T, and pH. It has been shown that the rate of conversion of C1 to F is much faster than that of C to C1 which is much faster than that of F to DHPD. The reaction step A → C involves general base (GB) catalysis, while step C → C1 seems to involve specific base–general acid (GA) and GB‐GB catalysis. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 147–161, 2005
Temperature Dependence of the Oxygen Solubility in Acrylates and its Effect on the Induction Period in UV Photopolymerization
Authors: Scherzer Tom , Langguth Helmut 
Published: January 2005

AbstractSummary: The influence of temperature on the kinetics of the UV photopolymerization of two diacrylates carried out under air was studied by real‐time FTIR‐ATR spectroscopy. In the temperature range up to 100 °C, the rate of polymerization obeys the Arrhenius law. The induction period was found to decrease with increasing temperature. It was shown that this decay is exclusively due to the decreasing solubility of oxygen in the acrylate. Moreover, from the induction period and the oxygen solubility, quantum yields of the α‐cleavage of some photoinitiators were estimated.Induction period calculated from the solubility of oxygen in TPGDA in comparison with experimental data from RT‐FTIR measurements.magnified imageInduction period calculated from the solubility of oxygen in TPGDA in comparison with experimental data from RT‐FTIR measurements.
Morphology and Deformation Behaviour of a Liquid Crystalline Polymer Containing Laterally Attached Pentaphenyl Rods
Authors: He Chaobin , Liu Puwei , Griffin Anselm C. , Smith Christopher W. , Evans Kenneth E. 
Published: January 2005

AbstractSummary: The morphology and deformation behaviour of a liquid crystalline polymer consisting of both laterally attached transverse rods and terminally attached rods were studied. A plaque specimen of the polymer was prepared using the melt‐compression method, which exhibited highly anisotropic Poisson's ratio behaviour. In its through‐thickness direction, its Poisson's ratio was approximately 0.54, and in the in‐plane it was approximately 0.43. This anisotropic behaviour is explained by the anisotropic morphology of the polymer plaque resulting from its compression preparation. The high Poisson's ratio in the through‐thickness direction is due to the unusual chain structure of the polymer. A simple analytical model is presented to describe the non‐linear strain dependent Poisson's ratio behaviour of the material.Representation of the arrangement of the main chain and transverse rod molecules, prior to, during, and at complete extension.magnified imageRepresentation of the arrangement of the main chain and transverse rod molecules, prior to, during, and at complete extension.