bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spiral imaging: A critical appraisal
Authors: Block Kai Tobias , Frahm Jens 
Published: May 2005

AbstractIn view of recent applications in cardiovascular and functional brain imaging, this work revisits the basic performance characteristics of spiral imaging in direct comparison to echo‐planar imaging (EPI) and conventional rapid gradient‐echo imaging. Using both computer simulations and experiments on phantoms and human subjects at 2.9 T, the study emphasizes single‐shot applications and addresses the design of a suitable trajectory, the choice of a gridding algorithm, and the sensitivity to experimental inadequacies. As a general result, the combination of a spiral trajectory with regridding of the k‐space data poses no principle obstacle for high‐quality imaging. On the other hand, experimental difficulties such as gradient deviations, resonance offset contributions, and concomitant field effects cause more pronounced and even less acceptable image artifacts than usually obtained for EPI. Moreover, when ignoring parallel imaging strategies that are also applicable to EPI, improvements of image quality via reduced acquisition periods are only achievable by interleaved multishot spirals because partial Fourier sampling and rectangular fields of view (FOVs) cannot be exploited for non‐Cartesian trajectories. Taken together, while spiral imaging may find its niche applications, most high‐speed imaging needs are more easily served by EPI. J. Magn. Reson. Imaging 2005;21:657–668. © 2005 Wiley‐Liss, Inc.
Digital subtraction dark‐lumen MR colonography: Initial experience
Authors: Ajaj Waleed , Veit Patrick , Kuehle Christiane , Joekel Michaela , Lauenstein Thomas C. , Herborn Christoph U. 
Published: May 2005

AbstractPurposeTo evaluate image subtraction for the detection of colonic pathologies in a dark‐lumen MR colonography exam.Materials and MethodsA total of 20 patients (12 males; 8 females; mean 51.4 years of age) underwent MR colonography after standard cleansing and a rectal water enema on a 1.5‐T whole‐body MR system. After suppression of peristaltic motion, native and Gd‐contrast‐enhanced three‐dimensional T1‐w gradient echo images were acquired in the coronal plane. Two radiologists analyzed the MR data sets in consensus on two separate occasions, with and without the subtracted images for lesion detection, and assessed the value of the subtracted data set on a five‐point Likert scale (1 = very helpful to 5 = very unhelpful). All imaging results were compared with endoscopy.ResultsWithout subtracted images, MR‐colonography detected a total of five polyps, two inflammatory lesions, and one carcinoma in eight patients, which were all verified by endoscopy. Using subtraction, an additional polyp was found, and readout time was significantly shorter (6:41 vs. 7:39 minutes; P < 0.05). In two patients, endoscopy detected a flat adenoma and a polyp (0.4 cm) that were missed in the MR exam. Sensitivity and specificity without subtraction were 0.67/1.0, and 0.76/1.0 with the subtracted images, respectively. Subtraction was assessed as helpful in all exams (mean value 1.8 ± 0.5; Likert scale).ConclusionWe consider subtraction of native from contrast‐enhanced dark‐lumen MR colonography data sets as a beneficial supplement to the exam. J. Magn. Reson. Imaging 2005;21:841–844. © 2005 Wiley‐Liss, Inc.
Proximal pulmonary artery blood flow characteristics in healthy subjects measured in an upright posture using MRI: The effects of exercise and age
Authors: Cheng Christopher P. , Herfkens Robert J. , Taylor Charles A. , Feinstein Jeffrey A. 
Published: May 2005

AbstractPurposeTo use MRI to quantify blood flow conditions in the proximal pulmonary arteries of healthy children and adults at rest and during exercise in an upright posture.Materials and MethodsCine phase‐contrast MRI was used to calculate mean flow and reverse flow index (RFI) in the main (MPA), right (RPA), and left (LPA) pulmonary arteries in healthy children and adults in an open‐MRI magnet equipped with an upright MRI‐compatible ergometer.ResultsFrom rest to exercise (150% resting heart rate), blood flow (liters/minute/m2) increased in the RPA (1.4 ± 0.3 vs. 2.5 ± 0.4; P < 0.001), LPA (1.1 ± 0.3 vs. 2.2 ± 0.6; P < 0.001), and MPA (2.7 ± 0.5 vs. 4.9 ± 0.5; P < 0.001). RFI decreased in the LPA (0.040 ± 0.030 vs. 0.017 ± 0.018; P < 0.02) and MPA (0.025 ± 0.024 vs. 0.008 ± 0.007; P < 0.03). Adults experienced greater retrograde flow in the MPA than the children (0.042 ± 0.029 vs. 0.014 ± 0.012; P < 0.02).ConclusionIt appears that at both rest and during exercise, in children and adults alike, RPA/LPA mean blood flow distribution is predominantly determined by distal vascular resistance, while retrograde flow is affected by proximal pulmonary bifurcation geometry. J. Magn. Reson. Imaging 2005;21:752–758. © 2005 Wiley‐Liss, Inc.
Magnetic resonance techniques for the in vivo assessment of multiple sclerosis pathology: Consensus report of the white matter study group
Authors: Filippi Massimo , Falini Andrea , Arnold Douglas L. , Fazekas Franz , Gonen Oded , Simon Jack H. , Dousset Vincent , Savoiardo Mario , Wolinsky Jerry S. 
Published: May 2005

AbstractOn October 9–11, 2003, the third meeting of the White Matter Study Group of the International Society for Magnetic Resonance in Medicine was held in Venice, Italy. This article is the report of the meeting on how to use MRI in the diagnostic workup of multiple sclerosis (MS) and allied white matter disorders, and to define the nature and the extent of MS pathology in vivo. Both of these steps are central to the design of future treatment strategies aimed at limiting the functional consequences of the most disabling aspects of this disease. J. Magn. Reson. Imaging 2005;21:669–675. © 2005 Wiley‐Liss, Inc.
Diffusion‐weighted images of the liver: Comparison of tumor detection before and after contrast enhancement with superparamagnetic iron oxide
Authors: Naganawa Shinji , Sato Chiho , Nakamura Tatsuya , Kumada Hisashi , Ishigaki Takeo , Miura Shunichi , Maruyama Katsuya , Takizawa Osamu 
Published: May 2005

AbstractPurposeTo study the recognition of malignant lesions of the liver on diffusion‐weighted images (DWI) can be improved by the administration of superparamagnetic iron oxide (SPIO).Materials and MethodsPre‐ and post‐SPIO mediated DWI of the liver was compared in six patients with suspected malignant liver lesions at 1.5 Tesla using a parallel imaging technique.ResultsPost‐SPIO DWI showed improved contrast‐to‐noise ratio between malignant lesions and liver. Furthermore, the spleen signal was decreased on post‐SPIO DWI, thus avoiding the overlap of the spleen and left lobe of the liver on maximum intensity projections (MIP).ConclusionRecognition of malignant lesions of the liver was improved by SPIO on DWI. On MIP images of DWI, SPIO helped to decrease the overlap of spleen signal on the liver in some projection angles. J. Magn. Reson. Imaging 2005;21:836–840. © 2005 Wiley‐Liss, Inc.
Expression of multiple integrins and extracellular matrix components by C6 glioma cells
Authors: Malek‐Hedayat S. , Rome L. H. 
Published: May 2005

AbstractWe have investigated the expression of integrins in C6 glioma, a chemically‐induced glial tumor cell line from rat brain. Immunochemical analysis revealed that C6 cells express sets of integrin receptor complexes which immunologically and electrophoretically are indistinguishable from those expressed hy normal rat skin fibroblasts. These include the well characterized fibronectin (α5β1) and the multi‐specific laminin, collagen and fibronectin (α3β1) receptors. Assay of cell adhesion indicated that C6 cells adhere fibronectin‐coated surfaces or matrix deposited by the c6 glioma cells (CGM) in an RGD‐ and divalent cation‐dependent fashion. However, anti‐fibronectin antibodies, which are able to inhibit fibroblast adhesion to fibronectin, did not inhibit adhesion of the C6 cells to fibronectin or CGM. This may reflect differences in functional properties and/or distribution patterns of integrins in C6 cells and normal fibroblasts.
Hippocampal NCAM180 transiently increases sialylation during the acquisition and consolidation of a passive avoidance response in the adult rat
Authors: Doyle E. , Nolan P. M. , Bell R. , Regan C. M. 
Published: May 2005

AbstractSynaptic connectivity change is a consistent anatomical feature of memory formation and the possibility that this is mediated by a replay of neurodevelopmental events has been investigated by measuring change in neural cell adhesion molecule sialylalion state during the acquisition and consolidation of a passive avoidance response in the adult rat. The avoidance response was always generated after two to three trials and the animals remained on the platform for the criterion time of 5 min. In all cases training was complete within 5–8 min. Change in sialylation state was monitored following intrayentricuiar infusion of the 3H‐ManNAc Precursor at 4 hr prior to the reference point. No task‐specific change in general glycoconjugate sialylation was apparent in hippocampal P2 pellets at increasing times following training. Increased sialylation state was observed only in neural cell adhesion molecule (NCAM) immunoprecipitates of hippocampal membrane fractions at 12 and 24 hr after training. Change in hippocampal sialylation state could not be attributed to an increased accumulation of NCAM as detected by an immunoabsorbent assay. Immunoblotting of antibody precipitated NCAM demonstrated the 3H‐ManNAc to be incorporated into the synapse‐specific, 180 kDa isoform of NCAM and a novel 210 kDa isoform. Immunoprccipitation and immunoblotting procedures with an antibody specific for a2‐8‐polysialic acid showed the 180 and 210 kDa isoforms to be polysialylated. The role of NCAM180 sialylation as a mechanism for synapse selection in information storage is discussed.
Distribution of calcium‐activated neutral protease inhibitor in the central nervous system of the rat
Authors: Kamakura K. , Ishiura S. , Imajoh S. , Nagata N. , Sugita H. 
Published: May 2005

AbstractThe ubiquitous existence of calcium‐activated neutral protease (CANP, calpain), an enzyme whose activity is regulated by calcium ions and a specific endogenous CANP inhibitor (calpastatin), is well known. Although there has been much investigation concerning the distribution and role of CANP, investigations of the distribution of the CANP inhibitor using immunohistochemical techniques are rare.We made antiserum against a 40K fragment of cDNA corresponding to two C‐terminal repeats of rat liver CANP inhibitor expressed in Escherichia coli. Using this antiserum, we examined the distribution of CANP inhibitor in the rat central nervous system by the ABC technique and compared it with the distribution of CANP. Neurons and glias were stained, with the cytosol stained diffusely and the cell membranes stained clearly and strongly. Axons and myelin were stained faintly, but nuclei and vessels were not stained. The distribution of CANP inhibitor was thus found to be similar to that of CANP.
Expression of platelet‐derived growth factor (PDGF) and PDGF receptor genes in the developing rat brain
Authors: Reddy U. R. , Pleasure D. 
Published: May 2005

AbstractSteady‐state levels of rat central nervous system (CNS) platelet‐derived growth factor (PDGF) A‐ and B‐chain mRNAs were measured by a polymerase chain reaction method employing a synthetic gene internal standard, and the rates of transcription of PDGF A‐ and B‐chain genes in CNS were estimated by a nuclear runoff assay. The abundance of PDGF B‐chain mRNA was an order of magnitude below that of PDGF A‐chain mRNA, while the rate of PDGF B‐chain transcription was only slightly below that for the PDGF A‐chain gene, indicating that the half‐life of PDGF B‐chain in CNS is shorter than that of PDGF A‐chain mRNA. No developmental alterations in expression of the PDGF A‐ and B‐chain genes were detected. By contrast, Northern blots showed that steady‐state levels of mRNAs encoding the two PDGF receptor proteins, α and β, were markedly higher in embryonic day 15 and postnatal day 6 rat brains than in later life. These results suggest that the actions of PDGF on the brain in vivo are regulated not at the level of PDGF A and B‐chain gene expression, but rather by changes in the level of expression of PDGF α‐ and β‐receptor genes.
Retinoic acid‐regulated expression of proteolipid protein and myelin‐associated glycoprotein genes in C6 glioma cells
Authors: Zhu W. , Kanoh M. , Ye P. , Laszkiewicz I. , Royland J. E. , Wiggins R. C. , Konat G. 
Published: May 2005

AbstractThe effect of retinoic acid (RA) on the expression of myelin‐specific genes, i.e., proteolipid protein (PLP) and myelin‐associated glycoprotein (MAG) in rat glioma C6 cells, was analyzed by Northern blot hybridization. RA‐treatment increased the steady‐state level of the PLP‐specific messages within one day alter RA administration and the upregulation reached a maximum on the third day. Concomitantly, the expression of MAG‐specific messages in the RA‐treated C6 cells dropped below the detectability limit. The expression of the PLP gene was directly related to the RA concentration increasing to approximately 44‐ fold over the control (untreated cells) level at 10−6 RA. The stimulatory effect was vitiated by cyclohex‐imide indicating the involvement of intermediate genes in the PLP gene activation. The total cellular RNA content and the level of cyclophilin mRNA was not changed by the RA‐treatment. The present data indicate that RA can be a potent modulator of the myelin‐specific gene expression. Furthermore, the reciprocal response of PLP versus MAG genes to RA demonstrates that these two genes utilize different regulatory mechanisms.
β‐Amyloid precursor protein of Alzheimer's disease in cultured bovine oligodendrocytes
Authors: Mizuguchi M. , Ikeda K. , Kim Seung U. 
Published: May 2005

AbstractThe production of β‐amyloid precursor protein (βAPP) in cultured oligodendrocytes isolated from adult bovine brains was examined by immunohistochemistry and immunoblotting. Immunostaining of oligodendrocytes with antibodies specific for the carboxy terminus of βAPP demonstrated positive immunoreactivity of oligodendroglial cytoplasm. Immunoblot analysis of cellular extracts detected two distinct bands with estimated molecular weight of 118 and 105 kDa. The amount of these βAPP subspecies increased considerably in response to their attachment to the poly‐L‐Iysine substratum. © 1992 Wiley‐Liss, Inc.
Exogenous gangliosides modulate calcium fluxes in cultured neuronal cells
Authors: Guérold B. , Massarelli R. , Forster V. , Freysz L. , Dreyfus H. 
Published: May 2005

AbstractPrevious work from this and other laboratories has shown that the neuritogenic effect due to exogenous gangliosides on primary neurons in culture is accompanied by several morphological and biochemical modifications. The present results indicate that the treatment of these neurons with gangliosides, under the experimental conditions which are known to produce a sprouting effect, inhibited the influx of 45Ca2+ and increased the release of 45Ca2+ from the cells. No significant differences were noted using concentrations of gangliosides (10−8‐10−5 M) either below or above the critical micellar concentrations. No apparent specificity was observed among various species of individual sialocompounds (GM1, GD1a). Moreover the presence or absence of fetal calf serum in the culture medium influenced the levels of 45Ca2+ fluxes. This study confirms the hypothesis that gangliosides may be considered as Ca2+ flux modulators in neuronal cells. © 1992 Wiley‐Liss, Inc.
Taurine release and swelling of cerebral cortex slices from adult and developing mice in media of different ionic compositions
Authors: Oja S. S. , Saransaari P. 
Published: May 2005

AbstractThe release of preloaded radiolabeled taurine was studied in superfused cerebral cortex slices obtained from adult and 3‐day‐old mice in media of varying ionic composition. Our aim was to establish whether the release of taurine from slices evokable by high concentrations of K+ could be attributed solely to cell volume changes or whether it results directly from depolarization of cell membranes. In both age groups hypoosmotic media enhanced the release of taurine. The enhancement was greater in 3‐day‐old than in adult mice. The K+‐evoked release of taurine was likewise greater in slices from 3‐day‐old mice than in slices from adult mice. The K+ stimulation was totally preserved in adult mice and partially preserved in 3‐day‐old mice when the slices were superfused with Cl−‐free media, with media in which the K+ × Cl− ionic product was kept constant and with hyperosmotic high‐K+ media. The results were practically the same when the permeant anion acetate and the impermeant anion gluconate were used to replace the Cl− deficit. The unstimulated release of preloaded taurine was greatly enhanced in Cl−‐free media in both age groups. There obtained no statistically significant correlation between the intracellular swelling of slices and the magnitude of taurine release under the present different experimental conditions in either age group. The results show that the K+‐evoked release of taurine from superfused cerebral cortex slices cannot be solely attributed to depolarization‐induced cell swelling. At least a part of the release results directly from membrane depolarization which besides exocytosis apparently also enhances the carrier‐mediated release of taurine and inhibits the reuptake of taurine liberated from intracellular compartments. © 1992 Wiley‐Liss, Inc.
Neurotrophin gene expression by cell lines derived from human gliomas
Authors: Hamel W. , Westphal M. , Szőnyi É. , Escandón E. , Nikolics K. 
Published: May 2005

AbstractThe expression of neurotrophin (NGF, BDNF, and NT‐3) mRNAs in 24 cell lines derived from human malignant gliomas was studied by Northern analysis. Widespread expression of neurotrophin genes was found with BDNF being the most abundantly expressed. Nearly all cell lines expressed BDNF, and about two‐thirds of the cell lines expressed NGF and NT‐3. Half of the cell lines analyzed expressed all three neurotrophins. Secretion of NGF into the medium of several cell lines could be detected by ELISA and a PC12 neurite outgrowth assay. Immuno‐ and bioactive NGF was isolated from conditioned medium of one cell line. No evidence of expression of the neurotrophin receptors trk and trkB by Northern analysis was found. Receptor crosslinking with radiolabeled cognate ligands failed to detect functional receptors in all but one cell line. In this cell line a receptor complex for BDNF was found that corresponded to truncated trkB receptors that lack the signal transducing tyrosine kinase domain. Neurotrophins did not stimulate mitosis of the glioma cultures. The findings suggest that production of neurotrophins by glioma cells is a general phenomenon, although neurotrophins made by gliomas lacking their receptors may not play an autocrine but rather a paracrine role. © 1993 Wiley‐Liss, Inc.
Modulation of voltage‐activated Ca currents by pain‐inducing agents in a dorsal root ganglion neuronal line, F‐11
Authors: Kusano K. , Gainer H. 
Published: May 2005

AbstractWhole cell currents evoked by pain‐inducing agents—bradykinin (Bk), capsaicin (Cap), and reciniferatoxin (RTX), and their modulation of voltage‐activated Ca currents were examined in F‐11 cells using a patch electrode voltage clamp technique. Most F‐11 cells generated action potentials under current clamp if their membrane potentials were held sufficiently negative. Average peak inward Na current (INa) was 100 μA/cm2 and the INa was abolished by 10−6 M tetrodotoxin. At least two types of Ca currents could be clearly distinguished on the basis of voltage dependency and kinetics; a low threshold transient ICa(t) and a high threshold sustained ICa(I). In addition, another high threshold transient Ca current, presumably ICa(n), was observed. About 30% of the cells produced inward current for these pain‐inducing agents, when activated at the membrane holding potential of −70 mV. In some F‐11 cells, the amplitude of action potential was observed to increase during 10−6 M Cap‐induced depolarization. Both low and high threshold Ca currents were reduced by 10−6 M Bk in the majority of the cells. Similarly, both 10−6 M Cap and 10−9 M RTX reduced these Ca currents. However, a considerable number of cells showed an initial enhancement followed by reduction in the amplitude of these Ca currents. With higher concentrations of these ligands, all Ca currents were suppressed. Such modulation of voltage‐activated Ca currents by pain‐inducing agents occurred in both the presence and absence of apparent receptor‐activated current flows in the cells. In pertussis toxin (PTX)‐treated cells, the inhibitory modulation of Ca currents by pain‐inducing agents was suppressed. In contrast, in cholera toxin (CTX)‐treated cells, this inhibitory modulation appeared to be enhanced. These data indicate that the inhibitory modulation of Ca channel currents by Cap and RTX, similarly to that of Bk, involves a PTX‐sensitive inhibitory G protein (Gi). © 1993 Wiley‐Liss, Inc.
Insulin‐like growth factor‐I (IGF‐I) production by astroglial cells: Regulation and importance for epidermal growth factor‐induced cell replication
Authors: Chernausek S. D. 
Published: May 2005

AbstractThe insulin‐like growth factor are postulated to play a role during brain development. Because they are believed to act in a paracrine/autocrine manner, the production of insulin‐like growth factor‐I (IGF‐I) by cultured astroglial cells was examined. Quantities of IGF‐I in conditioned media were determined by RIA after separation of IGFs from IGF‐binding proteins by high‐pressure liquid chromatography. Astrocytes from 1‐day‐old rats and the rat glioma cell line (C6) both secreted 7.5‐kDa IGF‐I. A peak of immunoreactivity with an apparent mol wt of 12,000 was additionally present in media conditioned by C6 cells. Exposure to epidermal growth factor (EGF) increased media content of immunocreactive IGF‐I slightly (60%) in C6 cells but more than 2‐fold in normal astrocytes. Fibroblast growth factor also increased the amount of IGF‐I contained in media conditioned by normal astrocytes. To determine whether the secreted IGF‐I was biologically active, media IGFs were immunoneutralized with a monoclonal antibody (Sm 1.25). In the presence of the antibody, EGF‐stimulated astrocyte replication was blocked. These data indicate that IGF‐I secretion by rodent astrocytes is stimulated by factors thought to be important for brain growth and development and that the IGFs are likely intimate participants in EGF‐induced astrocyte growth. © 1993 Wiley‐Liss, Inc.
Cell volume regulation in cultured cerebellar granule neurons
Authors: Pasantes‐Morales H. , Maar T. E. , Morán J. 
Published: May 2005

AbstractCultured rat cerebellar granule neurons exposed to solutions of reduced osmolarity, responded initially by swelling followed by a regulatory volume decrease (RVD) which is completed within 15 min. Increasing external osmolarity lead to cell shrinking but no evidence of volume regulation was observed within 1 hr. Replacing Na+ by choline did not affect RVD whereas N‐methyl‐D‐glucamine accelerated the volume recovery and K+ suppressed it completely. The blockade of RVD in high extracellular K+ was only observed when chloride and nitrate but not sulfate or gluconate were the accompanying anions. Replacing intracellular Cl−, by long incubations with gluconate, markedly inhibited RVD. Removal of extracellular Ca2+ or addition of dantrolene which blocks Ca2+ released from intracellular stores had no effect on RVD. Increasing extracellular taurine prevented RVD. These results indicate that membrane permeability to K+, Cl−, and taurine is increased by hyposmolarity and suggest the involvement of these molecules in RVD in granule neurons. © 1993 Wiley‐Liss, Inc.