bluuebunny/crossref_metadata_2025_split huggingface dataset:
Can MTR be used to assess cartilage in the presence of Gd‐DTPA2–?
Authors: Henkelman R.M. , Stanisz G.J. , Menezes N. , Burstein D. 
Published: December 2002

AbstractMagnetization transfer (MT) and T1 and T2 relaxation of normal, trypsinized, and interleukin‐1β (IL‐1β)‐treated cartilage were measured in the absence and presence of Gd‐DTPA2–. Without the addition of Gd‐DTPA2–, neither T1 nor T2 showed any significant change with cartilage damage. However, with Gd‐DTPA2–, trypsinized cartilage exhibited substantially shorter T1 than normal cartilage, as expected due to the glycosaminoglycan (GAG) loss in these samples, and associated increased Gd‐DTPA2– concentration. The T2 results were similar, but less dramatic. The MT pseudo first‐order exchange rate, RM0B, did not depend on the contrast agent concentration, as expected, and was significantly faster for trypsinized and slower for IL‐1β‐treated cartilage. In both cases, the MT fraction of the macromolecular pool M0B decreased while only trypsinized cartilage showed an increase in MT exchange rate R. The MT ratio (MTR) decreased with increasing Gd‐DTPA2– concentration. However, interpretation of the MTR results in the presence of Gd‐DTPA2– was complicated due to competing effects of increased longitudinal relaxivity and MT exchange. Therefore, in a cartilage sample with an unknown degree of GAG depletion and some collagen damage, a full MT analysis might be used to probe the molecular state of cartilage, but it would not be possible to use a simple MTR measurement after the administration of Gd‐DTPA2– to differentially determine the amount of cartilage degradation in the sample. Magn Reson Med 48:1081–1084, 2002. © 2002 Wiley‐Liss, Inc.
Signal behavior in continuously ramped 2D TrueFISP for whole‐body imaging
Authors: Fautz Hans‐Peter , Leupold Jochen , Hennig Jürgen , Scheffler Klaus 
Published: December 2002

AbstractA fast and robust imaging technique was developed based on a single‐slice TrueFISP acquisition using a slice excitation frequency that is incremented, or spatially “ramped,” with each repetition. The short acquisition time of single slices allows artifact‐free imaging during free breathing, which demonstrates the potential use of this technique for whole‐body screening. Overlapping positioning of consecutively acquired slices was used to provide gapless volume coverage in free‐breathing measurements. The image contrast of ramped TrueFISP was analyzed in detail using simulations and experiments. A high ramp speed results in an increased overall signal intensity and in a modification of the known T2/T1 contrast towards a proton density‐weighted contrast. A further increase in imaging speed is achieved with z‐interleaved phase‐encoding trajectories based on weighted transitions between adjacent views. Magn Reson Med 48:1085–1090, 2002. © 2002 Wiley‐Liss, Inc.
Increased serum albumin, γ globulin, immunoglobulin IgG, and IgG2 and IgG4 in autism
Authors: CROONENBERGHS J. , WAUTERS A. , DEVREESE K. , VERKERK R. , SCHARPE S. , BOSMANS E. , EGYED B. , DEBOUTTE D. , MAES M. 
Published: December 2002

Background. Research on the biological pathophysiology of autism has found some evidence that immune alterations may play a role in the pathophysiology of that illness. As a consequence we expected to find that autism is accompanied by abnormalities in the pattern obtained in serum protein electrophoresis and in the serum immunoglobulin (Ig) and IgG subclass profile.Method. We examined whether subjects with autism showed changes in total serum protein (TSP) and the serum concentrations of albumin, α1 globulin, α2 globulin, β globulin and γ globulins, IgA, IgM and IgG and the IgG subclasses IgG1, IgG2, IgG3 and IgG4, compared with normal controls.Results. We found significantly increased concentrations of TSP in autistic subjects, which were attributable to increased serum concentrations of albumin and γ globulin. Serum IgG, IgG2 and IgG4 were also significantly raised. In autism there were significant and positive correlations between social problems and TSP and serum γ globulin and between withdrawal symptoms and TSP and serum albumin and IgG.Conclusions. The results suggest that autism is characterized by increased TSP, a unique pattern obtained in serum protein electrophoresis, i.e. increased serum albumin and IgG, and by a specific IgG subclass profile, i.e. increased serum IgG2 and IgG4. The increased serum concentrations of IgGs in autism may point towards an underlying autoimmune disorder and/or an enhanced susceptibility to infections resulting in chronic viral infections, whereas the IgG subclass skewing may reflect different cytokine-dependent influences on autoimmune B cells and their products.
Searching for a Gulf War syndrome using cluster analysis
Authors: EVERITT B. , ISMAIL K. , DAVID A. S. , WESSELY S. 
Published: December 2002

Background. Gulf veterans report medically unexplained symptoms more frequently than non-Gulf veterans did. We examined whether Gulf and non-Gulf veterans could be distinguished by their patterns of symptom reporting.Method. A k-means cluster analysis was applied to 500 randomly sampled veterans from each of three United Kingdom military cohorts of veterans; those deployed to the Gulf conflict between 1990 and 1991; to the Bosnia peacekeeping mission between 1992 and 1997; and military personnel who were in active service but not deployed to the Gulf (Era). Sociodemographic, health variables and scores for ten symptom groups were calculated.Results. The gap statistic indicated the five-group solution as one that provided a particularly informative description of the structure in the data. Cluster 1 consisted of low scores for all symptom groups. Cluster 2 had veterans with highest symptom scores for musculoskeletal symptoms and high scores for psychiatric symptoms. Cluster 3 had high scores for psychiatric symptoms and marginally elevated scores for the remaining nine groups symptom groups. Cluster 4 had elevated scores for musculoskeletal symptoms only and cluster 5 was distinguishable from the other clusters in having high scores in all symptom groups, especially psychiatric and musculoskeletal.Conclusion. The findings do not support the existence of a unique syndrome affecting a subgroup of Gulf veterans but emphasize the excess of non-specific self-reported ill health in this group.
Endomorphin analogues containing D‐Pro2 discriminate different μ‐opioid receptor mediated antinociception in mice
Authors: Sakurada Shinobu , Watanabe Hiroyuki , Hayashi Takafumi , Yuhki Masayuki , Fujimura Tsutomu , Murayama Kimie , Sakurada Chikai , Sakurada Tsukasa 
Published: December 2002

The antagonistic actions of D‐Pro2‐endomorphins on inhibition of the paw withdrawal response by endomorphins were studied in mice. D‐Pro2‐endomorphin‐1 and D‐Pro2‐endomorphin‐2, injected intrathecally (i.t.), had no significant effect on the nociceptive thermal threshold alone. When D‐Pro2‐endomorphin‐1 (0.05–0.1 pmol) was injected simultaneously with i.t. endomorphin‐1 (5.0 nmol) or endomorphin‐2 (5.0 nmol), antinociception induced by endomoprhin‐1 was reduced significantly, whereas endomorphin‐2‐induced antinociception was not affected by D‐Pro2‐endomorphin‐1. Antinociception induced by i.t. endomorphin‐2 (5.0 nmol) was reduced significantly by its analogue, D‐Pro2‐endomorphin‐2 (100 pmol), but not by D‐Pro2‐endomorphin‐1. D‐Pro2‐endomorphin‐1. D‐Pro2‐endomorphin‐1 also antagonized the antinociceptive effect of i.t. DAMGO, a μ‐opioid receptor agonist, whereas D‐Pro2‐endomorphin‐2 failed to reduce the effect of DAMGO. These results suggest that endomorphin analogues containing D‐Pro2 are able to discriminate the antinociceptive actions of μ1‐ and μ2‐opioid receptor agonists at the spinal cord level.British Journal of Pharmacology (2002) 137, 1143–1146. doi:10.1038/sj.bjp.0705047
COMPUTATIONAL AEROACOUSTICS EXAMPLES SHOWING THE FAILURE OF THE ACOUSTIC ANALOGY THEORY TO IDENTIFY THE CORRECT NOISE SOURCES
Authors: TAM CHRISTOPHER K. W. 
Published: December 2002

Lighthill's Acoustic Analogy has been the dominant theory of aeroacoustics, especially jet aeroacoustics for almost fifty years. As yet, except for the u8 scaling law, which was derived by dimensional analysis, jet noise prediction based on the Acoustic Analogy approach has not been particularly successful. This paper examines some of the weaknesses and ambiguities in the formulation of the Acoustic Analogy theories. It is concluded that if the analogy is carried out completely, in the sense that the full wave propagation terms are retained in the propagation part of the equations of the analogy, then the theory offers no sensible noise source terms. To demonstrate that the Acoustic Analogy can fail to identify the correct noise sources, four examples are considered. They include an initial value problem, a boundary problem, the problem of weak solution and the problem of sound generation by instability waves in jets and mixing layers. These examples show clearly how, in each case, the Acoustic Analogy theory identifies the wrong noise source. Indeed, the Acoustic Analogy could provide, if not careful, misleading interpretation of the physics of sound generation. This paper is dedicated to Professor David G. Crighton, outstanding applied mathematician, world famous acoustician and a much respected friend.
Influence of network chain orientation on the mechanical property of epoxy resin filled with silica particles
Authors: Harada Miyuki , Morimoto Mitsuhiko , Ochi Mitsukazu 
Published: December 2002

AbstractWhen tensile stress was applied to epoxy resin filled with silica particles, we expected that the stress concentration would occur in the epoxy matrix near the interface between the matrix and the silica particles. We investigated the plastic deformation of the network chains near the interface, which was quantitatively evaluated using a polarized microscope FTIR technique. A biphenol‐type epoxy resin, which has a mesogenic group in the backbone moiety, was used as the matrix resin. As a result, reorientation of the network chains along the direction of the tensile stress near the interface with the silica particles was observed. Especially when the silica/matrix interface has good bonding properties, the reorientation of the network chains was observed at a larger area around the silica particles. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 787–794, 2003
Effect of filler–fiber interactions on compressive strength of fly ash and short‐fiber epoxy composites
Authors: Kulkarni S. M. , Kishore  
Published: December 2002

AbstractCompressive properties of epoxy composites reinforced with fly ash and fibers, which have differing aspect ratios, are studied. Retention of strength and modulus are observed for a greater range of fiber volume fractions following fly ash introduction into the system. A slight decrease in density was also observed when fly ash content was higher, making these composites with materials of differing aspect ratio bearing reinforcement systems suitable in weight specific applications. The investigations showed that strength decrease is larger in fiber‐bearing samples compared with only ash‐bearing samples. This decrease was ascribed to the tendency of fibers to bunch. When the ash filler was introduced, this tendency of fibers to cluster appears to be reduced, resulting in increased strength and modulus. Further attempts are made to analyze these interactions of fibers and fillers through observations made on the surfaces of failed samples by scanning electron microscopy. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 836–841, 2003
Acrylonitrile–butadiene–styrene toughened nylon 6: The influences of compatibilizer on morphology and impact properties
Authors: Araújo E. M. , Hage E. , Carvalho A. J. F. 
Published: December 2002

AbstractPolymer alloys have been used as an alternative to obtain polymeric materials with unique physical properties. Generally, the polymer mixture is incompatible, which makes it necessary to use a compatibilizer to improve the interfacial adhesion. Nylon 6 (PA6) is an attractive polymer to use in engineering applications, but it has processing instability and relatively low notched impact strength. In this study, the acrylonitrile–butadiene–styrene (ABS) triblock copolymer was used as an impact modifier for PA6. Poly(methyl methacrylate‐co‐maleic anyhydride) (MMA‐MA) and poly(methyl methacrylate‐co‐glycidyl methacrylate) (MMA‐GMA) were used as compatibilizers for this blend. The morphology and impact strength of the blends were evaluated as a function of blend composition and the presence of compatibilizers. The blends compatibilized with maleated copolymer exhibited an impact strength up to 800 J/m and a morphology with ABS domains more efi8ciently dispersed. Moderate amounts of MA functionality in the compatibilizer (∼5%) and small amounts of compatibilizer in the blend (∼5%) appear sufficient to improve the impact properties and ABS dispersion. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 842–847, 2003
Failure analysis of rubber toughened epoxy resin
Authors: Nigam Vineeta , Setua D. K. , Mathur G. N. 
Published: December 2002

AbstractFailure of the blends of epoxy cresol novolac resin (ECN) with varied proportions of carboxy terminated polybutadiene (CTPB) liquid functional rubber was studied. Addition of CTPB improves toughness as reflected in the improvement of tensile, flexural, and impact properties. However, 10 wt % of CTPB was the optimum concentration beyond which a rapid fall of properties, in all cases, was observed. Surface topography of the fractured surfaces, studied by scanning electron microscopy and atomic force microscopy, revealed marked changes in the phase morphology due to addition of rubber and also accounted for the variation of the strength properties. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 861–868, 2003
Mitochondrial localization of glucocortocoid receptor in glial (Müller) cells in the salamander retina
Authors: Psarra Anna‐Maria G. , Bochaton‐Piallat Marie‐Luce , Gabbiani Giulio , Sekeris Constantine E. , Tsacopoulos Marcos 
Published: December 2002

AbstractGlucocorticoid hormones regulate the transcription of nuclear genes by way of their receptors. In addition, these hormones modulate mitochondrial gene transcription by mechanisms that remain poorly understood. Using immunofluorescence labeling in isolated Müller and photoreceptor cells and in intact salamander retina, we found that the glucocorticoid receptor (GR) is localized in both cell types. Confocal laser scanning microscopy and double staining with cytochrome oxidase (COX) showed that GR is localized in the mitochondria of Müller cells, but not in the mitochondria of photoreceptors. GR also colocalizes with glutamine synthetase (GS) in the cytoplasm of Müller cells. GR is also localized in the microvilli of the distal process of Müller cells and in the synaptic terminal of photoreceptors. Pre‐incubation of Müller cells with 1 μM dexamethasone (DEX) for 7 h led to greater than 50% inhibition of the glutamate‐induced increase in mitochondrial NADH. This late effect of glucocorticoids on glutamate metabolism could be ascribed, in part, to a direct action of steroid hormones on mitochondrial metabolism. GLIA 41:38–49, 2003. © 2003 Wiley‐Liss, Inc.
Induction of matrix metalloproteinase‐9 (MMP‐9) in lipopolysaccharide‐stimulated primary astrocytes is mediated by extracellular signal‐regulated protein kinase 1/2 (Erk1/2)
Authors: Lee Woo Jong , Shin Chan Young , Yoo Byoung Kwon , Ryu Jae Ryun , Choi Eui Yul , Cheong Jae Hoon , Ryu Jong Hoon , Ko Kwang Ho 
Published: December 2002

AbstractIn the present study, we investigated whether the activation of protein kinase C (PKC) and extracellular signal‐regulated kinase 1/2 (Erk1/2) are involved in the induction of MMP‐9 in lipopolysaccharide (LPS)–stimulated primary astrocytes. The expression of MMP‐9 but not MMP‐2 was increased by LPS. LPS treatment induced activation of Erk1/2 within 30 min, which was dose‐dependently inhibited by PD98059, a specific inhibitor of the Erk kinase (MEK). In this condition, PD98059 blocked the increase in MMP‐9 protein and mRNA level as well as gelatin‐digesting activity. Inhibition of PKC activity blocked the LPS‐induced activation of Erk1/2 as well as MMP‐9 expression. In addition, activation of PKC by phorbol myristoyl acetate (PMA) activated Erk1/2 with concomitant increase in MMP‐9 production. Moreover, treatment of PD98059 dose‐dependently decreased the PMA‐induced MMP‐9 expression. The results from the present study suggest that induction of MMP‐9 by LPS in rat primary astrocytes is mediated, at least in part, by the sequential activation of PKC and Erk1/2. The Erk1/2‐mediated MMP‐9 induction may provide insights into the regulation of MMP‐9 production in CNS, which may occur in vivo in pathological situations such as CNS inflammation. GLIA 41:15–24, 2003. © 2003 Wiley‐Liss, Inc.
Loss of microglial ramification in microglia‐astrocyte cocultures: Involvement of adenylate cyclase, calcium, phosphatase, and Gi‐protein systems
Authors: Kalla Roger , Bohatschek Marion , Kloss Christian U.A. , Krol Janna , Von Maltzan Xenia , Raivich Gennadij 
Published: December 2002

AbstractReduction in microglial branching is a common feature in brain pathology and culminates in the transformation into small, rounded, microglia‐derived phagocytes in the presence of neural debris. The molecular factors responsible for this transformation are unknown. Here we explored the effect of different classes of intra‐ and extracellular stimuli in vitro on the morphology of ramified microglia cultured on a confluent astrocyte substrate. These studies showed a strong dose‐dependent effect for the Ca2+ ionophore calcimycine/A21837 (50 μM) and for dibutyryl‐cAMP (1 mM), with a loss of microglial ramification. Direct activation of the adenylate cyclase with forskolin (0.1 mM) also led to the disappearance of microglial branching. Okadaic acid (70 nM), the inhibitor of protein phosphatases 1 and 2A (PP1/PP2A), and pertussis toxin (12.5 μg/ml), a Gi‐protein inhibitor, also showed similar effects. No effect was observed for dibutyryl‐cGMP or for UTP; addition of ATP had a moderate effect, but only at very high, probably nonphysiological concentrations (100 mM). Extracellular matrix components such as keratatan‐sulfate, integrin receptor blockers, the disintegrins kistrin, echistatin, and flavoridin, or the serine protease thrombin all had no effect. Addition of prostaglandin D2 (PGD2), a molecule produced by activated microglial cells, had a transforming effect, but at concentrations two orders of magnitude higher than that of established PGD2 receptors. In summary, addition of agents causing intracellular elevation of Ca2+ and cAMP or inhibition of Gi‐proteins and phosphatases to ramified microglia cultured on top of confluent astrocytes leads to a rapid loss of microglial branching. Signaling cascades controlled by these molecules may play an important role in the regulation of this common physiological process in the injured brain. GLIA 41:50–63, 2003. © 2003 Wiley‐Liss, Inc.
Single neuron burst firing in the human hippocampus during sleep
Authors: Staba Richard J. , Wilson Charles L. , Fried Itzhak , Engel Jerome 
Published: December 2002

AbstractAlthough there are numerous non‐primate studies of the single neuron correlates of sleep‐related hippocampal EEG patterns, very limited hippocampal neuronal data are available for correlation with human sleep. We recorded human hippocampal single neuron activity in subjects implanted with depth electrodes required for medical diagnosis and quantitatively evaluated discharge activity from each neuron during episodes of wakefulness (Aw), combined stage 3 and 4 slow‐wave sleep (SWS), and rapid eye movement (REM) sleep. The mean firing rate of the population of single neurons was significantly higher during SWS and Aw compared with REM sleep (p = 0.002; p < 0.0001). In addition, burst firing was significantly greater during SWS compared with Aw (p = 0.001) and REM sleep (p < 0.0001). The synchronized state of SWS and associated high‐frequency burst discharge found in human hippocampus may subserve functions similar to those reported in non‐primate hippocampus that require burst firing to induce synaptic modifications in hippocampal circuitry and in hippocampal projections to neocortical targets that participate in memory consolidation. Hippocampus 2002;12:724–734. © 2002 Wiley‐Liss, Inc.
Transcriptional profiling reveals regulated genes in the hippocampus during memory formation
Authors: Donahue Christine P. , Jensen Roderick V. , Ochiishi Tomoyo , Eisenstein Ingrid , Zhao Mingrui , Shors Tracey , Kosik Kenneth S. 
Published: December 2002

AbstractTranscriptional profiling (TP) offers a powerful approach to identify genes activated during memory formation and, by inference, the molecular pathways involved. Trace eyeblink conditioning is well suited for the study of regional gene expression because it requires the hippocampus, whereas the highly parallel task, delay conditioning, does not. First, we determined when gene expression was most regulated during trace conditioning. Rats were exposed to 200 trials per day of paired and unpaired stimuli each day for 4 days. Changes in gene expression were most apparent 24 h after exposure to 200 trials. Therefore, we profiled gene expression in the hippocampus 24 h after 200 trials of trace eyeblink conditioning, on multiple arrays using additional animals. Of 1,186 genes on the filter array, seven genes met the statistical criteria and were also validated by real‐time polymerase chain reaction. These genes were growth hormone (GH), c‐kit receptor tyrosine kinase (c‐kit), glutamate receptor, metabotropic 5 (mGluR5), nerve growth factor‐β (NGF‐β), Jun oncogene (c‐Jun), transmembrane receptor Unc5H1 (UNC5H1), and transmembrane receptor Unc5H2 (UNC5H2). All these genes, except for GH, were downregulated in response to trace conditioning. GH was upregulated; therefore, we also validated the downregulation of the GH inhibitor, somatostatin (SST), even though it just failed to meet criteria on the arrays. By during situ hybridization, GH was expressed throughout the cell layers of the hippocampus in response to trace conditioning. None of the genes regulated in trace eyeblink conditioning were similarly affected by delay conditioning, a task that does not require the hippocampus. These findings demonstrate that transcriptional profiling can exhibit a repertoire of genes sensitive to the formation of hippocampal‐dependent associative memories. Hippocampus 2002;12:821–833. © 2002 Wiley‐Liss, Inc.
Human hippocampus and viewpoint dependence in spatial memory
Authors: King John A. , Burgess Neil , Hartley Tom , Vargha‐Khadem Faraneh , O'Keefe John 
Published: December 2002

AbstractVirtual reality was used to sequentially present objects within a town square and to test recognition of object locations from the same viewpoint as presentation, or from a shifted viewpoint. A developmental amnesic case with focal bilateral hippocampal pathology showed a massive additional impairment when tested from the shifted viewpoint compared with a mild, list length‐dependent, impairment when tested from the same viewpoint. While the same‐view condition could be solved by visual pattern matching, the shifted‐view condition requires a viewpoint independent representation or an equivalent mechanism for translating or rotating viewpoints in memory. The latter mechanism was indicated by control subjects' response latencies in the shifted‐view condition, although the amnesic case is not impaired in tests of mental rotation of single objects. These results show that the human hippocampus supports viewpoint independence in spatial memory, and suggest that it does so by providing a mechanism for viewpoint manipulation in memory. In addition, they suggest an extremely sensitive test for human hippocampal damage, and hint at the nature of the hipppocampal role in episodic recollection. Hippocampus 2002;12:811–820. © 2002 Wiley‐Liss, Inc.