bluuebunny/crossref_metadata_2025_split huggingface dataset:
NMR Study of L‐Shaped (Quinoxaline)platinum(II) Complexes − Crystal Structure of [Pt(DMeDPQ)(bipy)](PF6)2
Authors: Rotondo Enrico , Rotondo Archimede , Nicolò Francesco , Di Pietro Maria Letizia , Messina Maria Anna , Cusumano Matteo 
Published: October 2004

AbstractA 1H and 13C NMR study of nine PtII complexes of DMeDPQ [6,7‐dimethyl‐2,3‐bis(2‐pyridyl)quinoxaline] and BDPQ [2,3‐bis(2‐pyridyl)benzo[g]quinoxaline], and the crystal structure of one of them, are reported. The results are consistent with Cs symmetry of “L‐shaped square‐planar complexes”. The rigid seven‐membered chelated quinoxaline ligand holds the fused aromatic rings nearly perpendicular to the PtII coordination plane, generating the peculiar L‐shaped structure. Ancillary ligands in the residual coordination sites are: a) bidentate flexible‐planar 2,2′‐bipyridine (bipy; complexes 1 and 2); b) bidentate rigid‐planar dipyrido[3,2‐a:2′3′‐c]phenazine (dppz) or benzo[b]dipyrido[3,2‐h:2′,3′‐j]phenazine (bdppz; complexes 3−6); or c) 3‐substituted monodentate pyridines (3‐Rpy; complexes 7−9). The L‐shaped geometry has been exploited to gain insight into the steric and dynamic features that regulate the noncovalent interactions of these square‐planar complexes with DNA. We have shown previously, for [Pt(bipy)(n‐Rpy)2]2+, that bipy twisting can be frozen out on the NMR timescale below 260 K. Preservation of the Cs symmetry at low temperature indicates a lack of bipy fluxionality within these L‐shaped structures. The static butterfly‐like symmetric orientation of the quinoxaline pyridyl rings accounts for the hampered twisting of Pt(bipy), which is otherwise assisted by the synchronous “windscreen wiper” conrotatory rocking of the ancillary pyridine rings. The L‐geometry can also be used to monitor the ancillary n‐Rpy rotation by NMR spectroscopy. The quasi‐vertical quinoxaline pyridyl rings alignment leave room in the coordination plane for the crossing of the opposite pyridine rings, thereby reducing their rotational barriers about the Pt−N bond. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Potentiation of the osmosensitive taurine release and cell volume regulation by cytosolic Ca2+ rise in cultured cerebellar astrocytes
Authors: Cardin Velia , Lezama Ruth , Torres‐Márquez M. Eugenia , Pasantes‐Morales Herminia 
Published: October 2004

AbstractHyposmolarity (−30%) in cultured cerebellar astrocytes raised cytosolic Ca2+ concentration ([Ca2+]i) from 160 to 400 nM and activated the osmosensitive taurine release (OTR) pathway. Although OTR is essentially [Ca2+]i‐independent, further increase in [Ca2+]i by ionomycin strongly enhanced OTR, with a more robust effect at low and mild osmolarity reductions. Ionomycin did not affect isosmotic taurine efflux. OTR was decreased by tyrphostin A25 and increased by ortho‐vanadate, suggesting a modulation by tyrosine kinase or phosphorylation state. Inhibition of phosphatidylinositol‐3‐kinase activity by wortmannin markedly decreased OTR and the ionomycin increase. Conversely, OTR and the ionomycin effect were independent of ERK1/ERK2 activation. OTR and its potentiation by ionomycin differed in their sensitivity to CaM and CaMK blockers and in the requirement of an intact cytoskeleton for the ionomycin effect, but not for normal OTR. Changes in the actin cytoskeleton organization elicited by hyposmolarity were not observed in ionomycin‐treated cells, which may permit the operation of CaM/CaMK pathways involved in the OTR potentiation by [Ca2+]i rise. OTR potentiation by [Ca2+]i requires the previous or simultaneous activation/operation of the taurine release mechanism and is not modifying its set point, but rather increasing the effectiveness of the pathway, resulting in a more efficient volume regulation. This may have a beneficial effect in pathological situations with concurrent swelling and [Ca2+]i elevation in astrocytes. © 2003 Wiley‐Liss, Inc.
GABAA receptor‐expressing astrocytes in the supraoptic nucleus lack glutamate uptake and receptor currents
Authors: Israel Jean‐Marc , Schipke Carola G. , Ohlemeyer Carsten , Theodosis Dionysia T. , Kettenmann Helmut 
Published: October 2004

AbstractAn important function of astrocytes is the clearance of excess extracellular glutamate via specific carriers whose expression has become an astrocytic marker. In the present study, we found that a large population of astrocytes in the supraoptic nucleus (SON) of the rat hypothalamus lacks glutamate uptake currents and receptor responses but expresses GABAA receptors. Patch clamp recordings in acute hypothalamic slices that included the SON showed typical astrocytic membrane currents and demonstrated that GABA, via GABAA receptor activation, triggered a conductance increase with the reversal potential close to the Cl− equilibrium potential and a decrease in resting K+ conductance. Intracellular labeling with Lucifer Yellow revealed that these cells had a radial glia‐like morphology, with cell bodies lined up along the base of the brain and long processes traversing the nucleus; they were not dye‐coupled. Parallel immunocytochemical labelings showed that they expressed strong GABAA receptor and glial fibrillary acidic protein (GFAP) immunoreactivities. In addition, our electrophysiological and morphological analyses revealed another population of astrocytes in this nucleus, located next to the subarachnoid space. They were less numerous than the radial type, had a round morphology and few processes, and were dye‐coupled. Unlike the radial astrocytes, they showed little immunoreactivity for GABAA receptor or GFAP. Moreover, they did not respond to GABA but to glutamate, a response that was partially mimicked by aspartate, indicating glutamate transporter expression. Taken together, our observations add to growing evidence illustrating heterogeneity of astrocytes in the adult brain, a heterogeneity that reflects striking differences in form and function of astrocytic populations in regions as discrete as the SON of the hypothalamus. © 2003 Wiley‐Liss, Inc.
Estimation of absolute microglial cell numbers in mouse fascia dentata using unbiased and efficient stereological cell counting principles
Authors: Wirenfeldt Martin , Dalmau Ishar , Finsen Bente 
Published: October 2004

AbstractStereology offers a set of unbiased principles to obtain precise estimates of total cell numbers in a defined region. In terms of microglia, which in the traumatized and diseased CNS is an extremely dynamic cell population, the strength of stereology is that the resultant estimate is unaffected by shrinkage or expansion of the tissue. The optical fractionator technique is very efficient but requires relatively thick sections (e.g., ≥20 μm after coverslipping) and the unequivocal identification of labeled cells throughout the section thickness. We have adapted our protocol for Mac‐1 immunohistochemical visualization of microglial cells in thick (70 μm) vibratome sections for stereological counting within the murine hippocampus, and we have compared the staining results with other selective microglial markers: the histochemical demonstration of nucleotide diphosphatase (NDPase) activity and the tomato lectin histochemistry. The protocol gives sections of high quality with a final mean section thickness of >20 μm (h = 22.3 μm ± 0.64 μm), and with excellent rendition of Mac‐1+ microglia through the entire height of the section. The NDPase staining gives an excellent visualization of microglia, although with this thickness, the intensity of the staining is too high to distinguish single cells. Lectin histochemistry does not visualize microglia throughout the section and, accordingly, is not suited for the optical fractionator. The mean total number of Mac‐1+ microglial cells in the unilateral dentate gyrus of the normal young adult male C57BL/6 mouse was estimated to be 12,300 (coefficient of variation (CV) = 0.13) with a mean coefficient of error (CE) of 0.06. The perspective of estimating microglial cell numbers using stereology is to establish a solid basis for studying the dynamics of the microglial cell population in the developing and in the injured, diseased and normal adult CNS. © 2003 Wiley‐Liss, Inc.
Human oligodendrocyte precursor cells in vitro: Phenotypic analysis and differential response to growth factors
Authors: Wilson Heather C. , Onischke Claus , Raine Cedric S. 
Published: October 2004

AbstractFollowing experimental demyelination in rodents, oligodendrocyte precursor cells (OPCs) proliferate and differentiate into myelin‐producing oligodendrocytes which effect robust remyelination. In contrast, remyelination in multiple sclerosis, the major human demyelinating disease, is generally limited and transient. Rodent OPCs have been well characterized in vitro and their response to growth factors documented. Since there appear to be appreciable species differences in OPC growth factor responsiveness, and since human precursors have proven difficult to culture, the present study has investigated mitogenic growth factors for cultured fetal human OPCs. Moreover, because markers for cultured human OPCs are not well established, we also examined which of the extensively used rodent OPC markers also label human precursors. Using a culture system modified for fetal human oligodendroglia, we have shown for the first time that the platelet‐derived growth factor α receptor (PDGFαR) and A2B5 antigen are expressed together on human OPCs. Human precursors also expressed NG2 chondroitin sulfate proteoglycan, as did a proportion of O4+ preoligodendrocytes. Several growth factors known to affect rodent OPCs were tested and found to have similar effects on human cells. PDGF, neurotrophin 3 (NT3), and glial growth factor 2 (GGF2) promoted proliferation, while insulin‐like growth factor‐1 (IGF‐1), exerted a maturational effect. © 2003 Wiley‐Liss, Inc.
Early loss of astrocytes after experimental traumatic brain injury
Authors: Zhao Xueren , Ahram Abdullah , Berman Robert F. , Muizelaar J. Paul , Lyeth Bruce G. 
Published: October 2004

AbstractNeuronal‐glial interactions are important for normal brain function and contribute to the maintenance of the brain's extracellular environment. Damage to glial cells following traumatic brain injury (TBI) could therefore be an important contributing factor to brain dysfunction and neuronal injury. We examined the early fate of astrocytes and neurons after TBI in rats. A total of 27 rats were euthanized at 0.5, 1, 2, 4, or 24 h after moderate lateral fluid percussion TBI or after sham TBI. Ipsilateral and contralateral hippocampi were examined in coronal sections from −2.12 to −4.80 mm relative to bregma. Adjacent sections were processed with markers for either astrocytes or degenerating neurons. Astrocytes were visualized using glial fibrillary acidic protein (GFAP) or glutamine synthetase immunohistochemistry. Neuronal degeneration was visualized using Fluoro‐Jade (FJ) histofluorescence. At 30 min, there was a significant loss of GFAP immunoreactivity in ipsilateral hippocampal CA3 with some loss of normal astrocyte morphology in the remaining cells. The number of normal staining astrocytes decreased progressively over time with extensive astrocyte loss at 24 h. At 4 h, lightly stained FJ‐positive neurons were scattered in the ipsilateral CA3. The intensity and number of FJ‐positive neurons progressively increased over time with moderate numbers of degenerating neurons in the ipsilateral hippocampal CA3 evident at 24 h. We conclude that astrocyte loss occurs in the hippocampus early after TBI. The data suggest that loss of supporting glial cell may contribute to subsequent neuronal degeneration. © 2003 Wiley‐Liss, Inc.
Effects of electroacupuncture versus manual acupuncture on the human brain as measured by fMRI
Authors: Napadow Vitaly , Makris Nikos , Liu Jing , Kettner Norman W. , Kwong Kenneth K. , Hui Kathleen K.S. 
Published: October 2004

AbstractThe goal of this functional magnetic resonance imaging (fMRI) study was to compare the central effects of electroacupuncture at different frequencies with traditional Chinese manual acupuncture. Although not as time‐tested as manual acupuncture, electroacupuncture does have the advantage of setting stimulation frequency and intensity objectively and quantifiably. Manual acupuncture, electroacupuncture at 2 Hz and 100 Hz, and tactile control stimulation were carried out at acupoint ST‐36. Overall, electroacupuncture (particularly at low frequency) produced more widespread fMRI signal increase than manual acupuncture did, and all acupuncture stimulations produced more widespread responses than did our placebo‐like tactile control stimulation. Acupuncture produced hemodynamic signal increase in the anterior insula, and decrease in limbic and paralimbic structures including the amygdala, anterior hippocampus, and the cortices of the subgenual and retrosplenial cingulate, ventromedial prefrontal cortex, frontal, and temporal poles, results not seen for tactile control stimulation. Only electroacupuncture produced significant signal increase in the anterior middle cingulate cortex, whereas 2‐Hz electroacupuncture produced signal increase in the pontine raphe area. All forms of stimulation (acupuncture and control) produced signal increase in SII. These findings support a hypothesis that the limbic system is central to acupuncture effect regardless of specific acupuncture modality, although some differences do exist in the underlying neurobiologic mechanisms for these modalities, and may aid in optimizing their future usage in clinical applications. Hum. Brain Mapping 24:193–205, 2005. © 2004 Wiley‐Liss, Inc.
Encapsulation of biologics in self‐assembled fibers as biostructural units for tissue engineering
Authors: Wan Andrew C. A. , Yim Evelyn K. F. , Liao I‐Chien , Le Visage Catherine , Leong Kam W. 
Published: October 2004

AbstractThe concept of a “biostructural unit” is presented as the combination of biological and structural building blocks to create scaffolds or constructs via a bottom‐up approach. Three types of biostructural units were constructed using the process of fiber formation by interfacial polyelectrolyte complexation: protein‐encapsulated fiber, ligand‐immobilized fiber, and cell‐encapsulated fiber units. Water‐soluble chitin (WSC) and alginate were used as the polyelectrolyte combination to form fiber. Encapsulation and sustained release of bovine serum albumin from the fiber could be achieved, release profiles being dependent on the WSC/alginate concentration ratio. Released nerve growth factor (NGF) retained its bioactivity, as demonstrated on PC12 cells. Biotinylated fiber could be fabricated by biotinylating alginate before drawing fiber with WSC, enabling biotinylated NGF to be immobilized to fiber via an avidin bridge. The immobilized NGF induced the differentiation of PC12 cells seeded on the fiber. Bovine pulmonary endothelial cells, human dermal fibroblasts, and human mesenchymal stem cells were encapsulated, demonstrating good viability as determined by Live/Dead and WST‐1 assays. The assembly of biostructural units into constructs was illustrated by using human mesenchymal stem cell–encapsulated fiber units. Cells in the resulting constructs could be induced to differentiate along chondrogenic and osteogenic lineages. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 71A: 586–595, 2004
The dirty dozen: Tough treasury problems and how to solve them
Authors: Sagner James S. 
Published: October 2004

AbstractDue to recent recessions, many companies have downsized or outsourced critical functions. Treasury and Finance have suffered, as entire departments were eliminated. What's worse, companies have grown lax about optimizing cash use while retaining adequate controls. The author presents a dirty dozen of the toughest problems companies are wrestling with—and shows you how to handle them. © 2004 Wiley Periodicals, Inc.
VIEs shift billions back to the bottom line
Authors: Bean LuAnn , Jarnagin Bill 
Published: October 2004

AbstractVariable interest entities (VIEs), recently established by the FASB, force companies to hit their balance sheets with huge amounts of assets and liabilities. Exactly what are VIEs, and why is the FASB doing this? Is it a bold move to spark investor confidence or an unwise shock to the market? And what will the effect be on corporate restructuring and mergers?© 2004 Wiley Periodicals, Inc.
Relationship between vertebral bone marrow blood perfusion and common carotid intima‐media thickness in aging adults
Authors: Chen Wei‐Tsung , Ting‐Fang Shih Tiffany , Hu Chaur‐Jong , Chen Ran‐Chou , Tu Hsing‐Yang 
Published: October 2004

AbstractPurposeTo evaluate the relationship between vertebral marrow blood perfusion and common carotid intima‐media thickness (IMT) in aging adults.Materials and MethodsAn age‐ and sex‐matched case control study was conducted. Subjects were contacted and enrolled voluntarily according to a database containing 2258 cases that received carotid ultrasonography examination at our hospital in the previous two years. Forty‐three pairs of subjects (56 male, 30 female; aged 44–85 years, average 63 years) underwent dynamic contrast‐enhanced magnetic resonance (MR) study of the lumbar spine. The average peak enhancement percentage of the second to fourth lumbar vertebrae was used to represent the vertebral marrow perfusion status for each subject. The common carotid IMT, presence of plaque, peak enhancement percentage, body mass index (BMI), systolic and diastolic blood pressure, serum total cholesterol, high‐density lipoprotein (HDL), and triglycerol levels were acquired for statistical analysis.ResultsThe average peak enhancement percentage was significantly lower in thickened IMT group compared to the normal IMT group (73 ± 23 vs. 90 ± 27, P = 0.0023). The carotid IMT inversely correlated with vertebral peak enhancement percentage (r = −0.33, P = 0.0018). The vertebral peak enhancement percentage was significantly lower in subjects with presence of any carotid plaque (P = 0.032). Common carotid IMT was the only significant variable that was negatively associated with vertebral marrow perfusion after adjusting for the effect of sex, age, blood pressure, BMI, total cholesterol, HDL, and triglycerol level in linear regression model (P = 0.008).ConclusionOur data demonstrate the negative association between vertebral marrow blood perfusion and common carotid IMT. These results suggest that common carotid IMT may provide the information of tissue perfusion status of the vertebral bone marrow. J. Magn. Reson. Imaging 2004;20:811–816. © 2004 Wiley‐Liss, Inc.
Effective blood signal suppression using double inversion‐recovery and slice reordering for multislice fast spin‐echo MRI and its application in simultaneous proton density and T2 weighted imaging
Authors: Kuribayashi Hideto , Tessier Jean J. , Checkley David R. , Wang Yi‐Xiang , Hultin Leif , Waterton John C. 
Published: October 2004

AbstractPurposeTo design a multislice double inversion‐recovery fast spin‐echo (FSE) sequence, with k‐space reordered by inversion time at slice position (KRISP) technique, to produce black‐blood vessel wall magnetic resonance imaging (MRI).Materials and MethodsIn this sequence, central k‐space sampling for each slice is required at inversion time (TI) of the blood signal. To fill the entire k‐space, the peripheral lines are obtained less or greater the TI and using a rotating slice order. Blood flow signal suppression was first evaluated using a phantom. Simulation studies were used to investigate FSE image quality. The final sequence was then applied to the rabbit abdominal aorta MRI at 4.7 T.ResultsIn the flow phantom study, artifacts from slow‐flowing water were substantially reduced by the KRISP technique; residual water spins were dephased by the strong phase‐encoding gradient required for peripheral k‐space. These dephased spins flowed into the slice plane where the center of k‐space was being acquired at the TI of the flowing water signal. Multislice black‐blood MR images were successfully obtained in the rabbit abdomen using the sequence with the k‐trajectory optimized by the simulation study.ConclusionThe KRISP technique was effective both in multislice double inversion‐recovery FSE and in blood signal suppression. J. Magn. Reson. Imaging 2004;20:881–888. © 2004 Wiley‐Liss, Inc.
Pancreatic sarcoidosis: MRI features
Authors: Baroni Ronaldo H. , Pedrosa Ivan , Tavernaraki Ekaterini , Goldsmith Jeffrey , Rofsky Neil M. 
Published: October 2004

AbstractPancreatic sarcoidosis is a rare entity, and few reports in the literature describe the CT aspects of the disease. We report the MR features of a pathologically‐confirmed case of pancreatic sarcoidosis, which presented as multiple pancreatic masses with low signal intensity on T1‐weighted images, mild high signal intensity on T2‐weighted images, and decreased enhancement compared to the normal pancreas after administration of gadolinium. Pancreatic sarcoidosis should therefore be included in the differential diagnosis of multiple pancreatic masses with these MRI features. J. Magn. Reson. Imaging 2004;20:889–893. © 2004 Wiley‐Liss, Inc.
Protease‐activated receptor subtype expression in developing eye and adult retina of the rat after optic nerve crush
Authors: Rohatgi T. , Sedehizade F. , Sabel B.A. , Reiser G. 
Published: October 2004

AbstractProtease‐activated receptors (PARs), 7‐transmembrane domain G protein‐coupled receptors, are involved in tissue degeneration and repair upon injury. We demonstrate the expression of all four PAR subtypes in the postnatal eye and in retina of the adult rat by reverse transcription‐polymerase chain reaction (RT‐PCR). PAR‐1 is regulated developmentally in the eye, with a decrease from P1, P9, to P16, whereas levels for PAR‐2, PAR‐3, and PAR‐4 remain unchanged throughout. In the retina of the adult rat, PAR‐1 is highly expressed, whereas PAR‐2 and PAR‐3 are moderately expressed, compared to low PAR‐4 expression. To elucidate possible roles of PARs after trauma, we carried out semiquantitative RT‐PCR analysis of expression of all 4 PAR subtypes, beginning 6 hr after partial optic nerve crush (ONC) in the adult rat until 3 weeks after the mild trauma. Levels of PAR mRNA for all four subtypes were upregulated as early as 6 hr after unilateral ONC, except PAR‐3, which showed a delayed upregulation. PAR‐1, PAR‐3, and PAR‐4 mRNA levels returned to almost basal levels at 3 weeks post‐crush, whereas PAR‐2 mRNA level was still high by the end of 3 weeks after crush. Although the lesion was unilateral, PAR mRNA expression in the contralateral, uninjured side was affected to levels almost comparable to those in the injured side. Previous studies have shown an increase in thrombin levels at the site of injury, retinal ganglion cell degeneration by necrosis and apoptosis, and PAR activation as consequences of nerve crush. PAR upregulation because of nerve crush in the mild trauma model could act as an effector of early cell death. Eventual return of receptor mRNA to basal levels is consistent with neuroprotection. © 2003 Wiley‐Liss, Inc.