bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adenovirus‐mediated gene therapy of experimental gliomas
Authors: Perez‐Cruet M. J. , Trask T. W. , Chen S‐H. , Goodman J. C. , Woo S. L. C. , Grossman R. G. , Shine H. D. 
Published: January 2005

AbstractThe efficacy of adenovirus (ADV)‐mediated gene therapy to treat brain tumors was tested in a syngeneic glioma model. Tumor cells were transduced in situ with a replication‐defective ADV carrying the herpes simplex virus thymidine kinase (HSV‐tk) gene controlled by the Rous sarcoma virus promoter. Expression of the HSV‐tk gene enables the transduced cell to convert the drug ganciclovir to a form that is cytotoxic to dividing cells. Tumors were generated in Fischer 344 rats by stereotaxic implantation of 9L gliosarcoma cells into the caudate nucleus. Eight days later, the tumors were injected either with the ADV carrying the HSV‐tk (ADV‐tk) gene or a control ADV vector containing the β‐galactosidase (ADV‐βgal) gene and the rats were treated with either ganciclovir or saline. Tumor size was measured 20 days after implantation of 9L cells or at death. Rats treated with ADV‐βgal and ganciclovir or with ADV‐tk and saline had large tumors. No tumors were detected in animals treated with ADV‐tk and with ganciclovir at doses ≥80mg/kg. An infiltrate of macrophages and lymphocytes at the injection site in animals treated with ADV‐tk and ganciclovir indicated an active local immune reaction. In survival studies, all animals treated with ADV‐tk and ganciclovir have remained alive longer than 80 and up to 120 days after tumor induction whereas all untreated animals died by 22 days. These results demonstrate that ADV‐mediated transfer of HSV‐tk to glioma cells in vivo confers sensitivity to ganciclovir, and represents a potential method of treatment of brain tumors. © 1994 Wiley‐Liss, Inc.
Cytochrome P450 in rat astrocytes in vivo and in vitro: Intracellular localization and induction by phenytoin
Authors: Kempermann G. , Knoth R. , Gebicke‐Haerter P. J. , Stolz B.‐J. , Volk B. 
Published: January 2005

AbstractCytochrome P450IIB1,2 (nomenclature according to Nelson et al., DNA Cell Biol 12:1–51, 1993 and Volk et al., Neuroscience 42:215–235, 1991) immunoreactivity (P450‐IR) is associated with astrocytes both in vivo and in vitro. Although they are unevenly distributed throughout the brain with a preference for phylogenetically elder parts, no significant differences between astrocytes prepared from different brain regions were observed in astrocyte cultures. The percentage of strongly immunoreactive astrocytes decreased from 40% after 7 days in culture to 15% after 21 days. Essentially all astrocytes have a low but significant P450‐IR within this interval. Preembedding immunoelectron microscopy revealed peroxidase reaction products on the endoplasmic reticulum and on the outer membranes of mitochondrial and nuclear envelopes. Phenytoin (1 μM) added to the medium for 7 days significantly (1.22‐fold) increased the amount of total P450 in astrocyte homogenates as measured by spectrophotometry. Considerably more immunoreactive cells (1.5‐fold) were found in treated cultures than in controls. © 1994 Wiley‐Liss, Inc.
Lindane cytotoxicity in cultured neocortical neurons is ameliorated by GABA and flunitrazepam
Authors: Pomés A. , Frandsen A. A. , Suñol C. , Sanfeliu C. , Rodríguez‐Farré E. , Schousboe A. 
Published: January 2005

AbstractThe effect of lindane (γ‐hexachlorocyclohexane) on [35S]t‐butylbicyclophosphorothionate ([35S]TBPS) binding and GABA‐stimulated 36Cl− influx was investigated in cultured cerebral cortical neurons. In addition, the cytotoxic action of lindane as well as a protection by GABA and flunitrazepam were studied together with the ability of lindane to increase the intracellular concentration of free Ca2+. Lindane was found to be toxic to the neurons, an effect that could be completely prevented by the simultaneous presence of GABA (0.1 μM) and flunitrazepam (100 μM) and reduced by GABA alone. An interaction with the GABA receptor‐gated chloride channel was demonstrated by an inhibitory action of lindane on [35S]TBPS binding (IC50 188 ± 51 nM) and on GABA‐stimulated 36Cl− influx in the neurons. Lindane only marginally increased the intracellular Ca2+ concentration in the neurons. It is concluded that the cytotoxic action of lindane is mediated through interaction with GABA receptors in a manner essentially independent of changes in intracellular Ca2+ homeostasis. © 1994 Wiley‐Liss, Inc.
Tissue‐specific DNA methylation patterns of the rat glial fibrillary acidic protein gene
Authors: Condorelli D. F. , Nicoletti V. G. , Barresi V. , Caruso A. , Conticello S. , de Vellis J. , Stella A. M. Giuffrida 
Published: January 2005

AbstractThe glial fibrillary acidic protein (GFAP) is an intermediate filament protein, specific of the cytoskeleton of astrocytes in the central nervous system. In the present work, as a preliminary step to the study of glial‐specific gene expression, we cloned the rat GFAP gene, and we report the sequence of 1.9 kb of the 5′ flanking region, exon 1, and the majority of the first intron. By digestion with methylation‐sensitive restriction enzymes followed by Southern blot analysis, the methylation status of various CpG sites was examined in this genomic segment. We tested whether structural modification of the GFAP gene, such as DNA methylation, could be related to its tissue‐specific transcriptional activity. Therefore, we compared a GFAP‐expressing cell population (primary culture of astroglial cells), a mixed population of GFAP‐expressing and ‐nonexpressing cells (adult rat cerebral hemispheres), and a GFAP‐nonexpressing tissue (liver). In the 5′ flanking region we identified a CpG site at position −1176 whose level of methylation is inversely correlated to GFAP expression. In primary cultured astrocytes, 75% of the GFAP gene alleles were demethylated at this site, while the corresponding value obtained for the cerebral hemispheres was 45%, and for liver only 9%. On the basis of the sequence data, a CpG‐rich region (putative CpG island) was identified extending from −38 to + 347 and overlapping 80% of the first exon. HhaI and HpaII sites located in the putative CpG island showed a relatively high level of methylation in all the cell populations examined, and did not show any clear correlation with the level of GFAP gene expression or with the methylation status of the −1176 site. Further in vivo developmental studies and in vitro differentiation studies are necessary to better understand the functional differences of the various methylatable CpG sites in the 5′ end of the GFAP gene. © 1994 Wiley‐Liss, Inc.
Effect of persistent mouse hepatitis virus infection on MHC Class I expression in murine astrocytes
Authors: Correale J. , Li S. , Weiner L. P. , Gilmore Wendy 
Published: January 2005

AbstractNeurotropic strains of mouse hepatitis virus (MHV) have been used extensively for the study of viral pathogenesis in the central nervous system (CNS), serving as models for human neurological diseases such as multiple sclerosis (MS). MHV strains A59 and JHMV both cause acute and chronic encephalomyelitis and demyelination in susceptible strains of mice and rats. In acute disease, CNS damage is most likely the result of lytic infection in neurons and oligodendrocytes, and death can be prevented by the adoptive transfer of Class I‐restricted CD8+ T cells. However, in later stages of the disease induced by some MHV strains, virus tends to be restricted to astrocytes in a nonlytic infection, and the immune response appears to contribute to CNS damage. These data lead us to suggest that the astrocyte may play a central role in the neuropathogenesis of MHV infection. Consistent with this possibility, A59 has been reported to induce the expression of Class I molecules of the major histocompatibility complex (MHC) in glial cells following infection in vivo and in vitro. In this communication, we have examined the influence of persistent infection by both A59 and JHMV on MHC Class I expression in primary murine astrocytes. Persistence was characterized by the presence of intracellular viral antigen and mRNA in the absence of detectable infectious virus particles. Under these conditions, JHMV, but not A59, inhibited constitutive expression of the H‐2 Kb molecule, with the magnitude of inhibition increasing with postinfection time. A59 was not able to induce Class I during persistence, presumably due to the lack of infectious virus particles. Class I expression was restored by the addition of gamma‐interferon (IFN‐γ) to astrocytes persistently infected with either A59 or JHMV. Thus, Class I inhibition is not a permanent consequence of JHMV persistence, and persistence does not interfere with normal signalling pathways for Class I induction. © 1995 Wiley‐Liss, Inc.
Nerve growth factor‐activated protein kinase N modulates the cAMP‐dependent protein kinase
Authors: Volonté C. , Greene L. A. 
Published: January 2005

AbstractProtein kinase N (PKN) is a serine/threonine protein kinase rapidly activated by nerve growth factor (NGF) and other agents in various cell lines. The possible involvement of PKN in the multiple pathways of the NGF mechanism of action was previously established through the use of purine analogs, some of which are apparently specific inhibitors of this kinase. Since a PKN‐like activity is modulated in several cell lines by cAMP analogs and this activation requires the activity of cAMP‐dependent protein kinase. The aim of the present work is to investigate possible interactions between PKN and C‐PKA. Preincubation of the two kinases in the presence of ATP leads to potentiated phosphorylation of histone HF1, Kemptide (a substrate for C‐PKA, but not for PKN), and several additional substrates. This augmented phosphorylating activity is insensitive to 6‐thioguanine (an inhibitor for PKN, but not for C‐PKA) and is suppressed both by the Walsh inhibitor and by the regulatory subunit of PKA. PKN‐pretreated C‐PKA shows a significant decrease in Km for Kemptide and a substantial increase in Vmax. C‐PKA and PKN are widely expressed enzymes and the possibility of PKN‐dependent modulation of PKA in intact cells would therefore have biological implications for signal transduction mechanisms. © 1995 Wiley‐Liss, Inc.
Morphological and molecular response of the MOCH‐1 oligodendrocyte cell line to serum and interferon‐γ: Possible implications for demyelinating disorders
Authors: Li Y. , Atashi J. , Hayes C. , Reap E. , Hunt Steve , Popko Brian 
Published: January 2005

AbstractThe regional loss of oligodendrocytes is thought to be an important pathological event in a variety of demyelinating diseases of the central nervous system (CNS). Various components of serum, which are normally excluded from the CNS by the blood‐brain barrier, have been implicated as mediators of demyelinating disorders. We have examined the effects of high concentrations of serum (10% fetal bovine serum, FBS), as well as the cytokine interferon‐γ (IFN‐γ), on an oligodendrocyte cell line, MOCH‐1 cells. These cells changed from phase‐bright, small round cells with multiple thin, branched processes in 1% FBS medium to flat, fibroblast‐like cells with large cell bodies when cultured in 10% FBS medium or 1% FBS medium containing IFN‐γ. These morphological changes were accompanied by a large increase in expression of the astrocyte marker, glial fibrillary acidic protein (GFAP), as detected by Northern and Western blot analyses. In addition, Northern blot and fluorescence‐activated cell sorting analyses revealed that IFN‐γ induced a very large increase in major histocompatibility complex (MHC) class I expression in MOCH‐1 cells. MHC class II mRNA induction by IFN‐γ was also seen. In contrast, 10% FBS did not elevate either MHC class I or class II mRNA levels in MOCH‐1 cells. The morphological and molecular effects of 10% FBS and IFN‐γ were reversible. We suggest that the response of MOCH‐1 cells to high concentrations of serum and IFN‐γ may reflect an important in vivo response to oligodendrocytes to perturbations that occur in demyelinating disorders. © 1995 Wiley‐Liss, Inc.
Myelin glycoprotein P0 is expressed at early stages of chicken and rat embryogenesis
Authors: Zhang S.‐M. , Marsh R. , Ratner N. , Brackenbury Robert 
Published: January 2005

AbstractAlthough previous studies suggest that P0 is expressed only in myelinating Schwann cells, monoclonal antibody 1E8 reacts with P0, yet also stains early Schwann cell precursors and non‐myelinating Schwann cells (Bhattacharyya et al.: Neuron 7:831–844, 1991). We therefore characterized the 1E8 epitope and analyzed P0 mRNA expression during development. Immunoblot analyses of P0 fusion proteins and of deglycosylated P0 indicated that the 1E8 epitope is polypeptide. Northern blot and polymerase chain reaction (PCR) analyses revealed that P0 is encoded by a single mRNA that is expressed in chicken embryos as early as E4 and in rat embryos as early as E14. These data indicate that the antigen recognized by 1E8 in early chicken embryos is P0 and that, during development of both chickens and rats, P0 mRNA is expressed long before myelination. © 1995 Wiley‐Liss, Inc.
Glial cell line‐derived neurotrophic factor stimulates fiber formation and survival in cultured neurons from peripheral autonomic ganglia
Authors: Ebendal Ted , Tomac A. , Hoffer B. J. , Olson L. 
Published: January 2005

AbstractHuman recombinant glial cell line‐derived neurotrophic factor (GDNF) was tested for its ability to stimulate fiber formation and neuron survival in primary cultures of peripheral ganglia dissected from the chicken embryo. GDNF, first characterized by its actions on central nervous system (CNS) neurons, had a marked stimulatory effect on fiber outgrowth in sympathetic and ciliary ganglia. Weaker responses were evoked in sensory spinal and nodose ganglia and in the ganglion of Remak. In addition, survival of neurons from the sympathetic and ciliary ganglia was stimulated by GDNF at 50 ng/ml. The effects were not mimicked by the distant but related protein transforming growth factor beta 1 (TGFβ1). The profile of neurons stimulated by GDNF is also distinct from the patterns of stimulation shown by nerve growth factor (NGF), stimulation strongly sympathetic but not ciliary ganglia, and ciliary neurotrophic factor (CNTF), stimulating mainly the ciliary ganglion. Moreover, using in situ hybridization histochemistry, GDNF was demonstrated to be present in the pineal gland in the new born rat, a target organ for sympathetic innervation. The present results suggest that GDNF is likely to act upon receptors present in several autonomic and sensory neuronal populations. GDNF may serve to support fiber outgrowth and cell survival in peripheral ganglia, adding yet one more trophic factor to the list of specific proteins controlling development and maintenance of the peripheral nervous system. © 1995 Wiley‐Liss, Inc.
Acetyl‐L‐Carnitine arginyl amide (ST857) increases calcium channel density in rat pheochromocytoma (PC12) cells
Authors: Tewari K. , Simard J. Marc , Peng Y. B. , Werrbach‐Perez K. , Perez‐Polo J. R. 
Published: January 2005

AbstractWe used the patch clamp technique to study the effect of acetyl‐L‐carnitine arginyl amide (ALCAA) and of nerve growth factor (NGF) on availability of L‐type Ca2+ channels in rat pheochromocytoma (PC12) cells maintained in defined medium. Channel availability was measured as number of channels in the patch × the probability of opening (n.P0). In patches from control cells, cells exposed to NGF (10 ng/ml) for six days, and cells exposed to ALCAA (1 mM) for six days, n.P0, measured during 200–240 ms pulses to ‐10 mV (holding potential, −60 mV), was 0.102 ± 0.089 (5 cells), 0.173 ± 0.083 (5 cells), and 0.443 ± 0.261 (7 cells), respectively. The 4.3‐fold increase for the ALCAA‐treated cells was significantly different from control (P < 0.05), whereas that for the NGF‐treated cells was not. For the same conditions, the maximum number of superimposed openings at −10 mV was 1.3 ± 0.5 (6 cells), 1.6 ± 0.5 (8 cells), and 3.3 ± 1.8 (8 cells), with the value for the ALCAA‐treated cells being significantly different from control (P < 0.001). Additional analysis showed that the distribution of channel open times, the time constants, and the voltage dependence of activation were not changed by prolonged exposure to ALCAA. Short‐term exposure to both ALCAA as well as to the parent compound, acetyl‐L‐carnitine (ALCAR), did not cause an increase but rather a decrease in n.P0, and this short‐term effect of both compounds was blocked by neomycin, an inhibitor of phospholipase C. Together, our findings are consistent with the interpretation that short‐term exposure to ALCAA inhibits Ca2+ channel activity, possibly by increasing intracellular Ca2+, and that long‐term exposure causes an increase in Ca2+ channel density, possibly by increasing channel expression, with no change in Ca2+ channel properties. © 1995 Wiley‐Liss, Inc.
Excitatory amino acid release from astrocytes during energy failure by reversal of sodium‐dependent uptake
Authors: Longuemare M. C. , Swanson Raymond A. 
Published: January 2005

AbstractNon‐synaptic release may be the major route of excitatory amino acid (EAA) efflux during cerebral ischemia. Possible routes of non‐synaptic release include non‐specific anion channels, reversal of Na+‐, CI−‐, or Ca2+‐dependent uptake, and cell lysis. In the present study we employ a novel approach to show reversal of Na+‐dependent uptake as a major route of EAA efflux from astrocyte cultures under conditions of energy failure. Primary rat astrocyte cultures were subjected to combined blockade of glycolytic and oxidative metabolism after incubation with [3H]‐D‐aspartate (D‐ASP). Energy failure produced an efflux of D‐ASP that was maximal by 90 minutes. The efflux over this period was reduced by more than 50% in cells that had been pre‐loaded with PDC (L‐transpyrrolidine‐2,4‐dicarboxylic acid) or TBHA (threo‐β‐hydroxyaspartic acid), compounds that are competitive inhibitors of Na+‐dependent glutamate uptake. The effect of pre‐loading with the inhibitors was concentration dependent. No effect was seen if the inhibitors were added after induction of energy failure, suggesting that the attenuation of D‐ASP efflux resulted from binding of the inhibitors to an intracellular site. These results provide strong evidence that EAA efflux from astrocytes under conditions of energy failure occurs largely through reversal of Na+‐dependent uptake. © 1995 Wiley‐Liss, Inc.This article is a US Government work and, as such, is in the public domain in the United States of America.
Identification of a second glycine‐like fragment on the strychnine molecule
Authors: Aprison M. H. , Galvez‐Ruano Enrique , Lipkowitz K. B. 
Published: January 2005

AbstractStrychnine is a complex molecule that inhibits the physiological actions of glycine, an important inhibitory neurotransmitter in the spinal cord, brain stem, and other areas of many vertebrates. Since 1987, we have employed atomistic molecular modeling tools to find an explanation at the molecular level for how this antagonism works. We have located a second glycine‐like fragment in the strychnine molecule that, when compared to glycine in a three pair atom analysis, provides an excellent topological and electronic charge congruence. The topological congruence in the second glycine‐like fragment is much better than with the first fragment reported in 1987 when using a truncated strychnine molecule in the quantum mechanical analysis. A fourth negative atom, a characteristic of antagonists which we reported earlier (Aprison and Lipkowitz: J Neurosci Res 30:442–446, 1991; Aprison and Lipkowitz: J Neurosci Res 31:166–174, 1992) was found in strychnine. This result follows the pattern reported recently for the three weak glycine antagonists N, N‐dimethylmuscimol, N‐methyl‐THIP, and iso‐THAO, a bicyclic 5‐isoxazolol zwitterion. © 1995 Wiley‐Liss, Inc.
Diabetic neuropathy in the rat: 1. Alcar augments the reduced levels and axoplasmic transport of substance P
Authors: Di Giulio A. M. , Lesma E. , Gorio Alfredo 
Published: January 2005

AbstractThis study examined the sciatic nerve axonal transport of substance P‐like immunoreactivity (SPLI) and its basal content in stomach, sciatic nerve and lumbar spinal cord of 8‐ and 12‐week alloxan‐diabetic rats, respectively. One group of diabetic rats received acetyl‐l‐carnitine (ALCAR) throughout the experimental period. Alloxan treatment caused hyperglycemia and reduced body growth. Axonal transport of SPLI was studied by measurement of 24‐hour accumulation at a ligature on the sciatic nerve. There was a marked reduction (from 50% to 100% according to the nerve segment examined) of anterograde and retrograde accumulation of SPLI in the constricted nerve of 8‐week diabetic rats. In the sciatic nerve of ALCAR‐treated diabetic rats, the accumulation of SPLI was comparable to control values. In the sciatic nerve, lumbar spinal cord and stomach of 12‐week diabetic rats, there is a significant reduction of SPLI content. ALCAR treatment prevented SPLI loss in these tissues. Sciatic nerves showed the typical sorbitol increase and myo‐inositol loss that were significantly counteracted by ALCAR. This study suggests that ALCAR treatment prevents diabetes‐induced sensory neuropathy by improving altered metabolic pathways such as polyol activity and myo‐inositol synthesis, and by preventing the reduction of synthesis and axonal transport of substance P. © 1995 Wiley‐Liss, Inc.
Human choline acetyltransferase gene: Localization of alternative first exons
Authors: Chireux M. A. , Le Van Thai A. , Weber Michel J. 
Published: January 2005

AbstractTwo overlapping cosmids containing the 5′ end of human choline acetyltransferase (ChAT) gene have been cloned. Using heterologous probes, we localized two alternative first exons homologous to rodent ChAT exons R and M (Misawa et al.: J Biol Chem 267:20392–20399,1992). The sequence of rodent exon N was not conserved in the human gene. Northern blot analysis of mRNA purified from the human neuroepithelioma cell lines LA‐N2 and MC‐I‐XC revealed that both exons R and M were transcribed in mRNA species of 6.0 and 2.5 kb. Only the 6‐kb species was detected with both R‐ and M‐specific probes in the neuroepithelioma cell line CHP126. Reverse transcription‐polymerase chain reaction (RT‐PCR) analysis suggested that the major mRNA species in MC‐I‐XC and CHP126 cells contained the proximal part of exon M spliced to exon 1, which contains the alternative ACG initiation codon. RT‐PCR also allowed the characterization of a mRNA species containing exon R spliced to exon 1, but no species containing both exon R and the distal part of exon M could be detected. RT‐PCR was also used to evidence an alternative exon (tentatively numbered exon 8) in the coding sequence. © 1995 Wiley‐Liss, Inc.
Complement and cytokine gene expression in cultured microglia derived from postmortem human brains
Authors: Walker D. G. , Kim S. U. , McGeer P. L. 
Published: January 2005

AbstractMicroglia were successfully cultured from human brain tissue from normal and neurologically diseased cases obtained 3.5–10 hours postmortem. Final cell preparations were more than 99% pure as judged by latex bead phagocytosis, expression of microglial phenotypic markers, and absence of astrocytic markers. The expression of complement genes C1qB, C3, and C4 as well as genes for interleukin‐(IL‐)1α, IL‐1β, IL‐6, tumor necrosis factor (TNF)α, IL‐1 receptor antagonist, and transforming growth factor β, but not inducible nitric oxide synthase, by these cells was detected by polymerase chain reaction (PCR) analysis. The pattern of gene expression was evaluated following stimulation of the cells with lipopolysaccharide, phorbol myristate acetate, γ interferon, and β amyloid peptide. There was considerable variation in gene response to these activating agents. However, it was of interest that β‐amyloid peptide (1–40) increased the expression of IL‐1β mRNA in these cells. The number of cases in this study was too small to permit evaluation of microglial response according to the disease state, but the results demonstrate the potential for such studies in the future. © 1995 Wiley‐Liss, Inc.