bluuebunny/crossref_metadata_2025_split huggingface dataset:
T cell receptor Vβ gene usage in the recognition of myelin basic protein by cerebrospinal fluid‐ and blood‐derived T cells from patients with multiple sclerosis
Authors: Chou Y. K. , Burenafe A. C. , Dedrick R. , Morrison W. J. , Bourdette D. N. , Whitham R. , Atherton J. , Lane J. , Spoor E. , Hashim G. A. , Offner H. , Vandenbark A. A. 
Published: January 2005

AbstractBecause of its proximity to the central nervous system, the cerebrospinal fluid (CSF) represents an important source of T cells that potentially could mediate putative autoimmune diseases such as multiple sclerosis (MS). To overcome the low CSF cellularity, we evaluated culture conditions that could expand CSF T cells, with a focus on the expression of T‐cell receptor Vβ genes utilized by T cells specific for the potentially encephalitogenic autoantigen myelin basic protein (BP). Expansion of “activated” CSF cells with IL‐2/IL‐4 plus accessory cells optimally retained BP‐responsive T cells that over‐expressed Vβ1, Vβ2, Vβ;5, or Vβ;18, compared to expansion using supernatants from PHA‐stimulated blood cells, or anti‐CD3 antibody that led to different V gene bias and rare reactivity to BP. Sequential evaluation of paired CSF and blood samples from a relapsing remitting MS patient indicated that BP‐reactive T cells were present in CSF during the period of clinical activity, and the pattern of BP recognition in CSF was partially reflected in blood, even after CSF reactivity had dissipated during remission. Over‐expressed Vβ genes were not always constant, however, since in three sequential evaluations of a chronic progressive MS patient, Vβ genes over‐expressed in the first BP‐reactive CSF switched to a different Vβ gene bias that was present in the second and third CSF samples. Blood samples reflected each pattern of CSF Vβ gene bias, but retained the initial bias for at least 4 months after its disappearance from CSF. These data indicate that selective expansion of IL‐2/Il‐4‐responsive CSF cells favors growth of the BP‐reactive subpopulation, and, in a limited number of patients studied, reflected clinical disease activity. In comparison, blood T cells provided a partial but longer lasting reflection of the CSF BP reactivity and Vβ gene bias. © 1994 Wiley‐Liss, Inc.
Leukemia inhibitory factor prevents the death of axotomised sensory neurons in the dorsal root ganglia of the neonatal rat
Authors: Cheema S. S. , Richards L. , Murphy M. , Bartlett P. F. 
Published: January 2005

AbstractLeukemia inhibitory factor (LIF) has several characteristics of a neurotrophic factor for sensory neurons. Here we have investigated whether LIF also supports the survival of axotomised sensory neurons in vivo. Newborn rat pups received a unilateral sciatic nerve transection and the injury site was treated with gelfoam soaked in phosphate buffered saline (PBS), nerve growth factor (NGF), or LIF. Neuronal nucleoli in the L5 dorsal root ganglia were counted, appropriate corrections applied, and the resultant neuronal loss expressed as a percentage of the contralateral intact side. In animals where LIF was administered neuronal loss was significantly reduced: 2 days after LIF treatment neuronal loss was 19.5% compared to 43% in PBS‐treated animals; 3 days after LIF treatment neuronal loss was 20.4% compared to 40.2% in PBS‐treated animals; however, 7 days after LIF treatment there was no significant reduction in the number of neurons lost. The degree of rescue of sensory neurons in vivo by LIF was found to be similar to NGF, which was not surprising as both factors supported the survival of a similar population of sensory neurons in vitro. Rescue was not observed when LIF‐containing gelfoam was placed away from the axotomised nerve, suggesting that LIF's action may be associated with its retrograde transport or direct signalling at the site of nerve injury. © 1994 Wiley‐Liss, Inc.
Expression of the neural cell adhesion molecule and polysialic acid during early mouse embryogenesis
Authors: Probstmeier R. , Bilz A. , Schneider‐Schaulies J. 
Published: January 2005

AbstractThe expression of the neural cell adhesion molecule (N‐CAM) and α 2–8 linked polysialic acid (PSA), which is believed to be predominantly expressed on N‐CAM, was investigated during early embryonic development of the mouse (embryonic days 7.5 to 10.0). By immunocytochemistry, in tissue sections, N‐CAM and PSA were not detectable at embryonic day 7.5 but were expressed in the prominent body regions such as somites, unsegmented mesoderm, developing heart, and neuroectoderm at embryonic day 8.0 N‐CAM and PSA immunoreactivities were always predominantly associated with the plasma membrane. No tissue could be detected which was positive for PSA but negative for N‐CAM. In Western blot analysis of whole embryos, by contrast, only the lightly sialylated and PSA‐negative 180 and 140 kD isoforms of N‐CAM were present at embryonic day 8.0 and strong expression of PSA‐bearing, heavily sialylated N‐CAM was not detectable before embryonic day 10.0. In Western blot analysis of N‐CAM immunoaffinity purified from whole embryos and digested with neuraminidase as well as in Northern blot analysis, the 120 kD isoform of N‐CAM or its corresponding mRNA were not expressed in detectable amounts during the time period investigated. © 1994 Wiley‐Liss, Inc.
Tyrosine phosphorylation of glycoproteins in the adult and developing rat brain
Authors: Soulliere J. , Bissoon N. , Khurgel M. , Gurd J. W. 
Published: January 2005

AbstractThe tyrosine phosphorylation of glycoproteins in the adult and developing rat brain was investigated. Immunoblotting with anti‐tyr(P) antibodies identified a glycoprotein with an apparent Mr of 180,000 (GP180) as the major tyrosine‐phosphorylated protein in the concanavalin A (con A)‐binding fraction prepared from forebrain homogenates. This glycoprotein had the same electrophoretic mobility as the postysynaptic density (PSD)‐associated glycoprotein PSD‐GP180. Tyrosine‐phosphorylated GP180 was enriched 24‐fold in isolated PSDs relative tohomogenates. Digestion with endoglycosidase F/N‐glycosidase F demonstrated that GP180 present in total homogenates and PSD‐GP180 present in total homogenates and PSD‐GP180 present in isolated PSDs contained similar amounts of N‐linked oligosaccharide suggesting that they are the same glycoprotein. The tyrosine phosphorylation of GP180 in homogenates varied between brain regions with the highest levels occurring in cortical areas and the amygdala and low or undetectable amounts being present in hindbrain regions. Incubation of homogenates with adenosine triphosphate (ATP) resulted in the tyrosine phosphorylation of GP180 in all regions examined except the cerebellum and identified a second con A‐binding glycoprotein, GP110, which was phosphorylated on tyrosine. GP180 was not phosphorylated on tyrosine following the incubation of cerebellar homogenate, synaptic membranes, or PSDs with ATP. Tyr(P)‐GP180 was not detected prior to the onset of synaptogenesis, increased in parallel with the formation of synapses during the first 4 weeks of postnatal development of the frontal cortex and hippocampus, and then decreased 50–60% to adult levels. The results suggest that GP180 corresponds to the PSD glycoprotein PSD‐GP180 and are consistent with a role for this glycoprotein in synaptic development and signal transduction at the synapse. © 1994 Wiley‐Liss, Inc.
Amyloid precursor protein is enriched in radial glia: Implications for neuronal development
Authors: Trapp B. D. , Hauer P. E. 
Published: January 2005

AbstractThe amyloid precursor protein (APP) is a transmembrane glycoprotein and the source of the amyloid that accumulates in brains of individuals with Alzheimer's and other neurodegenerative diseases. Although its function is unknown, previous in vitro studies indicate that APP can facilitate neuronal cell adhesion and neuronal survival. If APP has a similar function in vivo, it should be expressed in fetal brain. To investigate this possibility, the present study determined the cellular distribution of APP in fetal and postnatal mouse brain. Immunocytochemistry and confocal microscopy detected abundant APP immunoreactivity in radial glial cells in fetal and early postnatal mouse brain. In mature mouse brain, APP was detected in neuronal perikarya and dendrites but not in astrocytes. These results support a functional role for APP during radial glia‐mediated neuronal histogenesis. © 1994 Wiley‐Liss, Inc.
Isolation and partial characterization of a cell‐surface heparan sulfate proteoglycan from embryonic rat spinal cord
Authors: Guiseppetti J. M. , McCarthy J. B. , Letourneau P. C. 
Published: January 2005

AbstractCell‐surface heparan sulfate proteoglycans (HSPGs) are potential mediators of neuronal cell adhesion, spreading, and neurite outgrowth on various extracellular matrix molecules. One possible site of HSPG attachment is a heparin binding domain of fibronectin, which is present in the synthetic peptide FN‐C/H II. In this study, HSPGs extracted from embryonic rat spinal cord by detergent were purified by ionexchange chromatography, gel filtration, and affinity chromatography on an agarose column coupled with FN‐C/H II conjugated to ovalbumin (OA). Heparitinase treatment of the iodinated HSPG fraction led to the appearance of a major protein core with a molecular size of 72 kDa, as determined by reducing SDS‐PAGE. The intact proteoglycan has a molecular size of approximately 150–165 kDa, containing heparan sulfate glycosaminoglycan chains of about 10–15 kDa. Anti‐HSPG antibodies recognized the 72 kDa core protein by immunoblotting, and stained the surface of spinal cord neurons, oligodendrocytes, and a subset of astrocytes. These results identify a cell‐surface HSPG that may mediate neuron‐substratum or neuron‐glia interactions in embryonic central nervous system. © 1994 Wiley‐Liss, Inc.
Dystrophin‐related protein is found in the central nervous system of mice at various developmental stages, especially at the postsynaptic membrane
Authors: Kamakura K. , Tadano Y. , Kawai M. , Ishiura S. , Nakamura R. , Miyamoto K. , Nagata N. , Sugita H. 
Published: January 2005

AbstractDystrophin deficiency is known to be the cause of X‐linked Duchenne muscular dystrophy (DMD). A recently cloned B3‐cDNA shares 80% homology with the C‐terminus and actin‐binding portion of dystrophin. This autosome‐derived gene product is called dystrophin‐related protein (DRP). DRP is known to exist in fetal muscles even in mdx mice, an animal model for X‐linked DMD, but not in mature mouse muscles. We raised a polyclonal antibody against a B3‐unique amino acid sequence (Ab‐LDP) and investigated the existence and distribution of DRP in the central nervous system (CNS) tissues of (mdx) and normal control B10 mice at various stages of development using immunoblotting and immunohistochemical methods. The former shows that DRP exists in the CNS of both B10 and mdx mice, regardless of the developmental stage, with the exception that the 420 kDa DRP band of the 15‐day fetus is faint. In immunohistochemical studies, the choroid plexus, some neurons, glial cells, pia mater, and blood vessels were stained with Ab‐LDP. Staining intensity did not differ between B10 and mdx mice of between developmental stages except that the 15‐day fetus stained only faintly. This is in contrast of the results obtained for muscles in which DRP localized to muscle membrane in embryo decreases and is assembled at the neuromuscular junction in adults. In addition, an electron microscopic study on the cerebral cortex from adult B10 mice was also performed and revealed Ab‐LDP staining of the postsynaptic membrane of dendrite and the rough endoplasmic reticulum of neurons. This is a new finding and is of interest because DRP is expressed at the neuromuscular junction and its localization is similar to that of the acetylcholine receptor. Wiley‐Liss, Inc.
Depolarizing agents and tumor necrosis factor‐α modulate protein phosphorylation in oligodendrocytes
Authors: Soliven B. , Takeda M. , Szuchet S. 
Published: January 2005

AbstractMembrane depolarization and changes in ionic fluxes have been implicated in the signaling mechanisms between neurons and glial cells. We report here that K+‐induced depolarization of cultured ovine oligodendrocytes (OLGs) decreases the phosphorylation of myelin basic protein (MBP) and 2′3′‐cyclic nucleotide phosphohydrolase (CNPase). Membrane depolarization and decrease in phosphorylation of MBP and CNPase can also be elicited by inhibition of the inward rectifier with Ba2+ but not by inhibition of outward K+ channels with 4‐aminopyridine or tetraethylammonium. These findings demonstrate that modulation of K+ currents can influence phosphorylation states of OLG proteins. Tumor necrosis factor‐α (TNF‐α), an immune peptide implicated in autoimmune demyelinating diseases, also inhibits the phosphorylation of these proteins. In contrast to elevated [K+]0, TNF‐α does not decrease the stimulatory effect of protein kinase C activators or phosphatase inhibitors on MBP and CNPase phosphorylation, suggesting that depolarizing agents and TNF‐α act via distinct mechanisms. We postulate that the presence of elevated extracellular K+ and/or cytokines under certain pathological conditions can perturb OLG function by altering the phosphorylation states of their proteins and perhaps affect myelin maintenance, contributing to demyelination. © 1994 Wiley‐Liss, Inc.
Isolation, characterization, and expression of cDNA clones that encode rat UDP‐galactose: Ceramide galactosyltransferase
Authors: Stahl N. , Jurevics H. , Morell P. , Suzuki K. , Popko B. 
Published: January 2005

AbstractUDP‐galactose:ceramide galactosyltransferase (CGT) (EC. 2.4.1.62) catalyzes the final step in the synthesis of galactocerebroside (GalC), a glycosphingolipid found in high amounts in the myelin sheath. Here, the isolation of rat CGT specific cDNA clones is reported. The CGT sequence contains an open reading frame of 1,623 bp which predicts a protein of Mr 61,126 Da. In transfection experiments the cDNA was found to confer CGT activity of Chinese hamster ovary cells. In rat brain the developmental expression pattern of CGT mRNA was similar to the myelination profile, whereas the sciatic nerve contained high amounts of CGT message over a long developmental period. CGT mRNA expression in the sciatic nerve was found to drop substantially following nerve injury and recover slowly when compared to the expression of mRNAs specific for the predominant myelin‐specific proteins. The absolute amounts of CGT message in sciatic nerve and brain were found to be comparable to those that encode the structural proteins of myelin. Except for low amounts in the kidney, the CGT mRNA was not detected in other tissues examined. Southern blot analysis revealed that the CGT protein is likely encoded by a single, relatively large gene. © 1994 Wiley‐Liss, Inc.
Astrogliosis in culture: III. Effect of recombinant retrovirus expressing antisense glial fibrillary acidic protein RNA
Authors: Ghirnikar R. S. , Yu A. C. H. , Eng L. F. 
Published: January 2005

AbstractInjury to the central nervous system (CNS) either from trauma or due to demyelinating/degenerating diseases results in a typical response of astrocytes, termed astrogliosis. This reaction is characterized by astrocyte proliferation, extensive hypertrophy of nuclei, cell body, and cytoplasmic processes and an increase in immunodetectable glial fibrillary acidic protein (GFAP). GFAP accumulation may cause a physical barrier preventing the reestablishment of a functional environment. Our studies have aimed at modulating astrogliosis by inhibiting or delaying GFAP synthesis in damaged and reactive astrocytes. The present study investigates the use of a recombinant retrovirus expressing antisense GFAP RNA in controlling the response of mechanically injured astrocytes. A 650 bp fragment from the coding region of mouse GFAP cDNA was cloned in the antisense orientation under the control of long terminal repeat (LTR) promoter of Moloney murine leukemia virus. Increase in GFAP as detected by immunocytochemical staining in injured astrocytes was inhibited by treatment with retrovirus expressing antisense GFAP RNA. Also, astrocytes at the site of injury in these scratched cultures did not show cell body hypertrophy compared to control cultures. These observations demonstrate that the increase in GFAP at the site of injury can be inhibited using retroviral treatment and indicate the potential of retrovirus‐mediated gene transfer in modulating scar formation in the CNS in vivo. These studies also shed light on the role of GFAP in maintaining the morphology of astrocytes. © 1994 Wiley‐Liss, Inc.
Glial cells derived from aged mouse brain in culture display both mature and immature astrocytic phenotypes
Authors: Vernadakis A. , Kentroti S. 
Published: January 2005

AbstractIn earlier studies, we established glial cell cultures derived from aged (18‐month‐old) mouse cerebral hemispheres (MACH) and have maintained them frozen at various passages. These cultures were characterized immunocytochemically and consist of: 5% oligodendrocytes (GalC+), 75% astrocytes‐type 1 (GFAP+ only), 15% astrocytes‐type 2 (GFAP+ + A2B5+), and 5% progenitor glial cells (A2B5+ only). In the present study, we isolated colonies from MACH passage 29 cultures and also colonies from MACH passage 19 transfected with the gene for SV40 large T antigen and further subcultured for 8 passages. Using double‐staining immunocytochemistry, we found in non‐transfected MACH passage 19 colonies consisting primarily of cells exhibiting only vimentin‐positive staining and are considered to be immature glioblasts; colonies consisting primarily of cells exhibiting GFAP+ + vimentin+ which are considered to be astrocytes at an intermediate stage of maturation; and colonies consisting predominantly of cells exhibiting GFAP+ only which are considered to be mature astrocytes. In contrast, colonies isolated from transfected MACH cultures consisted primarily of vimentin+ cells. In conclusion, astrocytes in cultures derived from aged brain continue to be variable as they are during development. However, their response to the microenvironment may differ during development and during aging. Thus, the availability of clones of mature and immature astrocytes offers the opportunity to study neuron‐glia interactions and the role of mature and immature astrocytes in neuronal aging and regeneration. © 1994 Wiley‐Liss, Inc.
Light‐dependent regulation of the transcriptional activity of the mammalian gene for arrestin
Authors: McGinnis J. F. , Austin B. J. , Stepanik P. L. , Lerious V. 
Published: January 2005

AbstractThe purpose of this investigation was to determine if the cyclic variations in the amount of arrestin mRNA that occur in the mouse retina during the light/dark cycle are controlled by light, a circadian clock, or both. In this study, an experimental paradigm was designed and used to distinguish among these molecular mechanisms. The data show that the initiation and the maintenance of an increased rate of syntheses of arrestin mRNA requires light and is not dependent on the time of day. Therefore the changes in transcriptional activity of the mouse arrestin gene are controlled by light, independent of circadian clock. The mechanism for this light‐dependent regulation of gene transcription in the retina is distinct from the light‐dependent increases in mRNA concentrations of early response genes which occur in the suprachiasmatic nucleus and a comparative analysis of such changes in these different regions of the CNS may lead to the identification of the molecular relationship between light‐ and circadian‐dependent gene regulation. © 1994 Wiley‐Liss, Inc.
p75 nerve growth factor receptor modulates p140trkA kinase activity, but not ligand internalization, in PC12 cells
Authors: Kahle P. , Barker P. A. , Shooter E. M. , Hertel C. 
Published: January 2005

AbstractThe biological activity of nerve growth factor (NGF) has been shown to be mediated by the p140trkA receptor tyrosine kinase, while the role of the p75 NGF receptor (p75NGFR) is still unresolved. Here we have investigated the relative contribution of p140trkA and p75NGFR to early consequences of NGF binding: ligand internalization, p140trkA autophosphorylation, and tyrosine phosphorylation of Shc, phospholipase Cγ‐1 (PLCγ‐1), and extracellular signal‐regulated kinases (ERKs). It was found that NGF internalization was neither prevented by blocking p140trkA activity using the protein kinase inhibitors methylthioadenosine, staurosporine, and K‐252a, nor by inhibiting NGF binding to p75NGFR with antibodies. However, when NGF binding to p140trkA was reduced by the use of a synthetic peptide corresponding to amino acids 36–53 of human p140trkA, internalization of NGF was decreased. Thus, at least in PC12 cells, internalization appears to require binding of NGF to p140trkA, but occurs irrespective of p140trkA kinase activity and ligand occupancy of p75NGFR. The NGF triple mutant Lys‐32/Lys‐34/Glu‐35 to Ala, which has been demonstrated to bind to p140trkA, but not to p75NGFR, induced tyrosine phosphorylation more rapidly than wild‐type NGF. Likewise, NGF‐induced tyrosine phosphorylation was accelerated when NGF binding to p75NGFR was prevented with REX‐IgG. These findings indicate that NGF binding by p75NGFR may modulate NGF‐induced p140trkA kinase activity. © 1994 Wiley‐Liss, Inc.
Resolving three types of chloride channels in demyelinated Xenopus axons
Authors: Wu J. V. , Shrager P. 
Published: January 2005

AbstractAxons from Xenopus sciatic nerve were demyelinated by intraneural injection of lysolecithin rendering the entire internodal axolema accessible to a patch electrode. In this region, three types of anion selective pores were found and characterized at the single‐channel level. These included outwardly rectifying, inwardly rectifying, and maxi Cl− channels. The outwardly rectifying Cl− channels (24 pS) are activated by depolarization with a weak voltage dependence of 42 mV per e‐fold change in open probability. The inwardly rectifying Cl− channels (27 pS) are insensitive to voltage, but can be blocked by internal application of 100 μM SITS or DIDS. The I‐V curves of rectifying channels are S‐shaped and can be fitted by a kinetic model with a single free energy barrier. The rectification may be related to the location of this barrier. The maxi Cl− channel (335 pS) is often open at the resting potential, but is inactivated by a large depolarization. The rectification, voltage dependence, and inactivation of these channels may contribute to the regulation of axonal Cl− balance and resting potential. © 1994 Wiley‐Liss, Inc.
Regulation of nitric oxide synthase activity in cortical slices by excitatory amino acids and calcium
Authors: Alagarsamy S. , Lonart G. , Johnson K. M. 
Published: January 2005

AbstractNitric oxide synthase (NOS) activity was determined in adult rat frontal cortex and hippocampus by measuring the conversion of L‐[3H]arginine to L‐[3H]citrulline. N‐methyl‐D‐aspartate (NMDA), but not kainate or α‐amino‐3‐hydroxy‐5‐methylisoxazole‐4‐propionate (AMPA), stimulated NOS activity. This effect was concentration dependent (EC50 ≈ 30μM) and was inhibited by tetrodotoxin, EGTA, Nω‐nitro‐L‐arginine (NOARG), Mg2+, phencyclidine, and (cis)‐4‐phosphonomethyl‐2‐piperidine carboxylate (CGS 19755), but not by 6‐cyano‐7‐nitroquinoxaline‐2,3‐dione (CNQX). NOS activity was increased to an even greater extent by the calcium ionophores ionomycin and A23187 and by depolarization with 50 mM K+. Interestingly, neither caffeine nor 1‐aminocyclopentane‐1,3‐dicarboxylic acid (1S,3R‐ACPD), drugs that would be expected to increase intracellular Ca2+ concentration by release of Ca2+ from intracellular ryanodine‐ and inositol‐1,4,5‐trisphosphate‐sensitive stores, respectively, had any significant effect on NOS activity. It is concluded that NOS can be activated by NMDA binding to a classic NMDA glutamate receptor subtype as well as by depolarization or other agents that increase the influx of extracellular Ca2+. The paradoxical lack of effect of caffeine, as well as the inhibitory effect of tetrodotoxin, are discussed. © 1994 Wiley‐Liss, Inc.