bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunolocalization of ciliary neuronotrophic factor in adult rat sciatic nerve
Authors: Rende Mario , Muir David , Ruoslahti Erkki , Hagg Theo , Varon Silvio , Manthorpe Marston 
Published: January 2005

AbstractTwo rabbit polyclonal antibodies were raised against synthetic peptides corresponding to residue numbers 45–59 and 181–200 of rat ciliary neuronotrophic factor (CNTF). The resulting antibodies were purified by affinity chromatography and both purified antibodies reacted by enzyme‐linked immunoassay (ELISA) and immunoblotting with rat sciatic nerve CNTF. The anti‐CNTF peptide antibodies were used to immunostain sections of adult rat sciatic nerve, previously known as the richest tissue source of CNTF. By light microscopy both antibodies appeared to stain exclusively Schwann cells and axons and both did so with the same pattern of specific staining. Immunostaining was eliminated by absorption of the anti‐peptide antibodies with either their corresponding peptide or with purified rat nerve CNTF or by using purified nonspecific IgG. Schwann cells were stained and in semi‐thin sections this staining appeared to be in the Schwann cell cytoplasm. Axons could be stained in addition to Schwann cells providing higher concentrations of antibodies were used. Epineurial, endoneurial and endothelial cells appeared unstained. Since all Schwann cells and axons appear to contain CNTF and since CNTF is known to act in vitro to support sensory and sympathetic ganglionic and motor neurons, we suggest that Schwann cells may normally provide CNTF to those neurons contributing axons to the peripheral nerve.
Reperfusion paradox: A novel mode of glial cell injury
Authors: Kim‐Lee Myung H. , Stokes Bradford T. , Yates Allan J. 
Published: January 2005

AbstractWe have attempted to reconstruct in vitro the events that may occur in vivo during reperfusion injury after ischemia in the central nervous system. The phenomenon is induced by previous exposure to low calcium solutions (“calcium paradox”) before the reperfusion episode. Intracellular calcium alterations during reperfusion of human astrocytoma U1242MG cells have been investigated with microspectrofluorimetry using the calcium‐sensitive dye fura‐2. Cells were perfused in calcium‐free buffer solution for 30 min and then re‐exposed to the control buffer solution (1.5 mM CaCl2). [Ca2+]i increased up to 3.5 times control levels during the reperfusion period. The mechanism of the increase was also investigated. Addition of TTX (2 μM) or choline chloride sodium substitution during perfusion with low calcium prevented the [Ca2+]i increase during reperfusion. Reperfusion increases in [Ca2+]i were exacerbated by low potassium in the perfusion medium, but unaltered by the calcium channel blockers cadmium (100 μM) and nickel (100 μM). In a similar manner, flunarizine (10 μM) and cadmium (100 μM) were unable to modify reperfusion [Ca2+]i alterations. Low sodium in the reperfusion medium produced significant increases in [Ca2+]i if preceded by low potassium and calcium perfusion. The viability of cells after 24 h of incubation after the insult produced by exposure to Ca2+‐free media for 30 min was also investigated. Compared with control groups, the groups treated with Ca2+‐free media for 30 min had a decreased number of surviving cells and morphological alterations indicative of cell pathology. The relative number of cytotoxic cells was increased by maneuvers (low potassium perfusion) that presumably blocked the Na/K ATPase. These data support the hypothesis that calcium entry during reperfusion is via the Na/Ca exchanger and suggest a mechanism by which glia could become irreversibly injured in vivo. Such delayed pathological processes could exacerbate already described mechanisms of cell death in the central nervous system.
Characterization of Gsα mRNA transcripts in primary cultures of rat brain astrocytes
Authors: Feinstein Douglas L. , Mumby Susanne M. , Milner Robert J. 
Published: January 2005

AbstractA cDNA clone encoding a stimulatory G‐protein α subunit (Gsα) was isolated from a cDNA library derived from cultured rat astrocytes. The nucleotide sequence of the cDNA indicated that it corresponds to the Gsα‐2 form og Gsα mRNA, one of four Gsα mRNAs known to be derived by alternative splicing from the human Gsα gene. A ribonuclease protection assay using cRNA from this clone allowed distinction between the Gsα‐1 and Gsα‐2 mRNAs, which encode the 52‐kDa (Gs‐L) forms of Gsα. Astrocytes express relatively high amounts of Gsα‐1 mRNA, much lower amounts of the Gsα‐2 mRNA, and no detectable amounts of the mRNAs (Gsα‐3 and Gsα‐4) encoding the two 45‐kDa forms of Gsα (Gsα‐S). Similar results were obtained with RNA samples isolated from whole brain. The 45‐kDa form of Gsα protein was not detectable by immunoblot analysis of a membrane preparation from rat cerebral corted (the source of the astrocyte cultures). These results indicate that the expression of Gsα forms in astrocytes is similar to that found in whole brain.
Migration of grafted rat astrocytes: Dependence on source/target organ
Authors: Hatton James D. , Garcia Ruel , Sangu Hoi 
Published: January 2005

AbstractNeonatal rat cortical astrocytes migrate extensively after transplantation into the brains of adult hosts. However, the effects of cues provided by different sources of donor astrocytes and by different target sites of implantation on this migration is unknown. In order to investigate the significance of regional influences on glial migration, we established primary cultures of astrocytes derived from 1–3 day old rat cerebral cortex, hippocampus, and hypothalamus. After in vitro labelling with either Fast Blue or fluorescein‐labelled latex beads, these astrocytes were inoculated into different target regions of the adult rat brain by stereotaxic injection with a Hamilton syringe. Astrocytes implanted into the cerebral cortex imgrated extensively throughout the adult brain regardless of their donor source. These implanted cells were intimately associated with the ventricular wall, glial limitans, vasculature, and fiber bundles. Astrocytes homografted into the hippocampus and the hypothalamus migrated primarily within and around the respective homotopic target organs. Migration of astrocytes derived from cerebral cortex was also limited when injections were made into these two regions. In these latter cases, migration appeared to be less guided by other cellular or regional cues than was migration after implantation into the cerebral cortex. These results suggest that the migration patterns of astrocytes grafted after tissue culture are more dependent on the target implantation site than on the donor organ. © 1992 Wiley‐Liss, Inc.
Reactive astrocytes in myelin‐deficient rat optic nerve reveal an altered distribution of orthogonal arrays of particles (OAP)
Authors: Rohlmann Astrid , Gocht Andreas , Wolburg Hartwig 
Published: January 2005

AbstractReactive astrocytes are a common feature of various pathological conditions within the CNS. Morphological changes of reactive astrocytes include an altered nucleus‐cytoplasm relationship, nuclear indentations, an increased amount of intermediate filaments, and an immunologically immature phenotype. Additionally, the number of orthogonal arrays of particles (OAP) was found to be increased within parenchymal membranes of reactive astrocytes. This observation prompted us to investigate the distribution of astroglial OAP in the amyelinated CNS of the myelin‐deficient (md) rat in which reactive astrocytes prevail. In the present freeze‐fracture study, astroglial OAP were determined within endfoot and nonendfoot (parenchymal) membranes in the developing optic nerve of md rats and normal littermates at the age of 12, 23, 40, and 64 days postnatally (dpn).The endfoot OAP density in md astrocytes remained constant during the entire period of investigation. In myelinated littermates, OAP densities continuously increased up to adult values. In contrast, the parenchymal OAP density in md astrocytes increased during the entire period of investigation. In normal littermates, OAP densities remained constant during the first 40 dpn and thereafter increased rapidly. These observations suggest that the absence of myelinogenesis in the md mutant may be a stimulus for parenchymal membranes of reactive astrocytes to insert OAP or to assemble OAP subunits into complete arrays. © 1992 Wiley‐Liss, Inc.
Heme oxygenase is a heat shock protein and PEST protein in rat astroglial cells
Authors: Dwyer Barney E. , Nishimura Robert N. , De Vellis Jean , Yoshida Tadashi 
Published: January 2005

AbstractCultured rat forebrain astrocytes contained significant amounts of immunostainable heme oxygenase‐1 (HO‐1) isozyme, whereas HO‐1 was undetectable in spontaneously transformed rat astroglial cells (ATs). HO‐1 was inducible in both cell types by heat shock and by submicromolar amounts of H2O2. Inhibition of RNA synthesis with actinomycin D or protein synthesis with cycloheximide resulted in the rapid loss of immunostainable heme oxygenase in astrocytes. Analysis of the primary structure of heme oxygenase suggests that it is a PEST protein, i.e., targeted for rapid turnover. © 1992 Wiley‐Liss, Inc.
Sodium channel expression in optic nerve astrocytes chronically deprived of axonal contact
Authors: Minturn J. E. , Sontheimer H. , Black J. A. , Ranson B. R. , Waxman S. G. 
Published: January 2005

AbstractImmunocytochemical and electrophysiological methods were used to examine the effect of retinal ablation on the expression of sodium channels within optic nerve astrocytes in situ and in vitro. Enucleation was performed at postanatal day 3 (P3), and electron microscopy of the enucleated optic nerves at P28–P40 revealed complete degeneration of retinal ganglion axons, resulting in optic nerves composed predominantly of astrocytes. In contrast to control (non‐enucleated) optic nerve astrocytes, which exhibited distinct sodium channel immunoreactivity following immunostaining with antibody 7493, the astrocytes in enucleated optic nerves did not display sodium channel immunoreactivity in situ. Cultures obtained from enucleated optic nerves consisted principally ( > 90%) of glial fibrillary acidic protein (GFAP)+/A2B5− (“type‐1”) astrocytes, as determined by indirect immunofluorescence; GFAP+/A2B5+ (“type‐2”) astrocytes were not present, nor were GFAP−/A2B5+ (O‐2A) progenitor cells. Sodium channel immunoreactivity was not present in GFAP+/A2B5− astrocytes obtained from enucleated optic nerves; in contrast, GFAP+/A2B5− astrocytes from control optic nerves exhibited 7493 immunostaining for the first 4–6 days in culture. Sodium current expression, studied using whole‐cell patch‐clamp recording, was attenuated in cultured astrocytes derived from enucleated optic nerves. Whereas 39 of 50 type‐1 astrocytes cultured from intact optic nerves showed measurable sodium currents at 1–7 days in vitro, sodium currents were present in only 6 of 38 astrocytes cultured from enucleated optic nerves. Mean sodium current densities in astrocytes from the enucleated optic nerves (0.66 ± 0.3 pA/pF) were significantly smaller than in astrocytes from control optic nerves (7.15 ± 1.1 pA/pF). The hχ‐curves of sodium currents were similar in A2B5− astrocytes from enucleated and control rat optic nerves. These results suggest that there is neuronal modulation of sodium channel expression in type‐1 optic nerve astrocytes, and that, following chronic loss of axonal association in vivo, sodium channel expression is down‐regulated in this population of optic nerve astrocytes. © 1992 Wiley‐Liss, Inc.
Response of microglial cells to experimental rat glioma
Authors: Morioka Takato , Baba Takehiko , Black Keith L. , Streit Wolfgang J. 
Published: January 2005

AbstractThe response of indigenous CNS microglia to an experimentally induced glioma has been studied in rat brain using lectin histochemistry with the Griffonia simplicifolia B4‐isolectin. The study was undertaken 2 weeks after tumor cell injection when tumor size was near maximal. Reactive microglial cells formed a dense band that surrounded most of the well‐circumscribed tumor mass, and extended along the corpus callosum into the contralateral cerebral hemisphere. From the periphery inward, reactive microglia extended into the tumor tissue, where large numbers of them were found to be present as microglia‐derived macrophages. The lectin stain, which also labels endo thelial cells, revealed a highly vascularized tumor with ongoing neovascularization apparent as vascular sprouts. Moderate numbers of lectin‐stained blood monocytes were localized primarily inside the vessel lumina. Our results show that microglial cells react to brain tumors; however, it remains to be determined whether the microglial response represents an active antitumor defense mechanism that could be manipulated during immunotherapeutic approaches. © 1992 Wiley‐Liss, Inc.
Determination of the origin and nature of brain macrophages and microglial cells in mouse central nervous system, using non‐radioactive in situ hybridization and immunoperoxidase techniques
Authors: De Groot Corline J. A. , Huppes Wim , Sminia Taede , Kraal Georg , Dijkstra Christine D. 
Published: January 2005

AbstractThe origin and nature of brain macrophages and microglial cells in the mouse central nervous system (CNS) were investigated. First, the expression and localization of determinants recognized by the different monoclonal antibodies (mAbs) MOMA‐1, Mac‐1‐α, and F4/80 (raised against cells of the mononuclear phagocyte system) were immunohistochemically studied in the developing and adult mouse brain. In order to clarify the origin of brain macrophages and microglial cells, we used bacteriophage λ transgenic mice as donors for bone marrow transplantations in recipient mice of different ages.During ontogeny, numerous MOMA‐1‐, Mac‐1‐α‐, and F4/80‐positive blood monocytederived brain macrophages (amoeboid microglia) infiltrated the CNS parenchyma. These brain macrophages gradually disappeared from the brain parenchyma at postnatal day 7 (P7). From P17 on, Mac‐1‐α‐ and F4/80‐positive cells were detected within the brain parenchyma with the morphology of resting microglial cells. Transitional forms between brain macrophages and “resting” microglia were not observed in the developing brain.Combined non‐radioactive in situ hybridization and immunohistochemistry revealed many MOMA‐1‐positive bone marrow‐derived brain macrophages that were located in the leptomeninges, the ventricles, and occasionally the blood vessel walls. These results show that brain macrophages are of bone marrow origin. Many “resting” microglial cells were detected in the brain, mainly in the white matter. It appeared that about 10% of these cells displayed the transgenic signal. This result indicates that the majority of “resting” microglial cells are of local, presumably neuroectodermal, origin. © 1992 Wiley‐Liss, Inc.
Mechanisms of intercellular calcium signaling in glial cells studied with dantrolene and thapsigargin
Authors: Charles Andrew C. , Dirksen Ellen R. , Merrill Jean E. , Sanderson Michael J. 
Published: January 2005

AbstractMechanical stimulation of a single cell in a primary mixed glial cell culture induced a wave of increased intracellular calcium concentration ([Ca2+]i) that was communicated to surrounding cells. Following propagation of the Ca2+ wave, many cells showed asynchronous oscillations in [Ca2+]i. Dantrolene sodium (10 μM) inhibited the increase in [Ca2+]i associated with this Ca2+ wave by 60‐80%, and prevented subsequent Ca2+ oscillations. Despite the markedly decreased magnitude of the increase in [Ca2+]i, the rate of propagation and the extent of communication of the Ca2+ wave were similar to those prior to the addition of dantrolene. Thapsigargin (10 nM to 1 μM) induced an initial increase in [Ca2+]i ranging from 100 nM to 500 nM in all cells that was followed by a recovery of [Ca2+]i to near resting levels in most cells. Transient exposure to thapsigargin for 2 min irreversibly blocked communication of a Ca2+ wave from the stimulated cell to adjacent cells. Glutamate (50 μM) induced an initial increase in [Ca2+]i in most cells that was followed by sustained oscillations in [Ca2+]i in some cells. Dantrolene (10 μM) inhibited this initial [Ca2+]i increase caused by glutamate by 65‐90% and abolished subsequent oscillations. Thapsigargin (10 nM to 1 μm) abolished the response to glutamate in over 99% of cells. These results suggest that while both dantrolene and thapsigargin inhibit intracellular Ca2+ release, only thapsigargin affects the mechanism that mediates intercellular communication of Ca2+ waves. These findings are consistent with the hypothesis that inositol trisphosphate (IP3) mediates the propagation of Ca2+ waves whereas Ca2+ ‐induced Ca2+ release amplifies Ca2+ waves and generates subsequent Ca2+ oscillations.
The inhibition of oligodendrocytic differentiation of O‐2A progenitors caused by basic fibroblast growth factor is overridden by astrocytes
Authors: Mayer Margot , Bögler Oliver , Noble Mark 
Published: January 2005

AbstractThe inhibition of differentiation of oligodendrocyte‐type‐2 astrocyte (O‐2A) progenitors into oligodendrocytes caused by basic fibroblast growth factor (bFGF) can be overcome by non‐O‐2A lineage cells present in the optic nerve and by astrocytes purified from cerebral cortices. Although purified O‐2A progenitors grown in the presence of bFGF for up to 6 days were inhibited from differentiating into oligodendrocytes, O‐2A progenitors growing in heterogeneous optic nerve cultures did not show a similar inhibition of differentiation. The factor(s) responsible for overriding the inhibitory effects of bFGF appeared to be secreted by astrocytes, as extensive generation of oligodendrocytes was seen in cultures of purified O‐2A progenitors exposed to bFGF+ medium conditioned by purified astrocytes (ACM). In addition, purified O‐2A progenitors displayed a remarkable sensitivity to bFGF, which extended at least down to concentrations of 0.03 ng/ml, a concentration of <2 × 10−12 M. At a bFGF concentration of just 0.1 ng/ml, this mitogen still promoted DNA synthesis in as many O‐2A progenitors as in cultures exposed to 1‐30 ng/ml of this growth factor, but exhibited a reduced ability to promote DNA synthesis in oligodendrocytes. In addition, although concentrations of bFGF as low as 0.03 ng/ml were a potent stimulator of DNA synthesis in O‐2A progenitors, application of this amount of bFGF no longer inhibited the differentiation of progenitors into oligodendrocytes as effectively as application of higher bFGF concentrations. Thus, the induction of DNA synthesis by bFGF can be uncoupled from the inhibition of differentiation. Our results demonstrate that exposure of O‐2A progenitors to bFGF is not necessarily associated with an inhibition of differentiation. This result may have relevance to understanding the paradox posed by the combined observations that bFGF, along with other members of the FGF family, appear to be abundantly expressed in the CNS during development, yet oligodendrocytes nonetheless are generated in vivo. In addition, the differing effects of exposure to bFGF we observed in heterogeneous optic nerve cultures vs. cultures of purified O‐2A progenitors underscore the importance of utilizing purified cell cultures to examine the direct effects of a particular factor on differentiation, in concert with the use of heterogeneous cultures to examine the complex situations which may more closely resemble the biology of the intact organism. © 1993 Wiley‐Liss, Inc.
A blood‐derived attachment factor enhances the in vitro growth of two glial cell types from adult cockroach
Authors: Howes E. A. , Armett‐Kibel C. , Smith P. J. S. 
Published: January 2005

AbstractReactive glial cells from chemically‐lesioned areas of the central nervous system (CNS) of adult cockroaches (Periplaneta americana) have been grown in vitro on a substrate of fibronectin. This paper reports the enhancement of growth that is achieved when blood cells, serum, or medium conditioned by a 2‐h incubation with blood cells are used as an alternative substrate. Glial cells rapidly grew out from connective explants to form extensive radial mats of cells linking up with those from adjacent explants on each of the blood‐derived substrates. In addition to supporting the growth of reactive glial cells, characterised by their long, thin, branching morphology, these substrates also revealed the presence of a second type of glial cell, not previously found on fibronectin. Such cells, derived from ganglionic explants, behaved in a very different way to the reactive glia, initially spreading out to form a flattened sheet of phase‐bright cells, before migrating away over the culture surface. The growth‐enhancing effects of this blood‐derived factor may play a role in the events following damage to the insect CNS, where it is known that the entry of blood cells into the lesion site is an important precursor to the rapid and structured repair seen in this system. © 1993 Wiley‐Liss, Inc.
Muscarinic acetylcholine receptor‐expression in astrocytes in the cortex of young and aged rats
Authors: van der Zee E. A. , de Jong G. I. , Strosberg A. D. , Luiten P. G. M. 
Published: January 2005

AbstractThe present report describes the cellular and subcellular distribution pattern of immunoreactivity to M35, a monoclonal antibody raised against purified muscarinic acetylcholine receptor protein, in astrocytes in the cerebral cortex of young and aged rats. Most M35‐positive astrocytes were localized in the superficial layers of the cortex and part of the corpus callosum. At the ultrastructural level, immunoprecipitates were localized in the Golgi complexes, but the nucleus, rough endoplasmic reticulum, mitochondria, and microfilaments were generally free of labeling. Labeling was also present associated to the cell membrane, although without the characteristic immunoreactive postsynaptic membrane thickening found in neuronal structures. In aging rats of 30‐34 months, the number of M35‐labeled astrocytes doubled, whereas the neuronal staining slightly decreased in the same region in half of the animals studied. Fluorescent double‐labeling for M35 and GFAP, an astrocytic microfilament protein, revealed that all M35‐positive glial cells express GFAP and, conversely, that almost all GFAP glial cells were M35‐immunostained. Based on the high incidence of coexpression of mAChRs and GFAP, both proteins may be functionally linked to each other. Rough semiquantitative estimates revealed that in young adult rats the GFAP/M35‐immunoreactive astrocytes made up approximately one fifth of all cortical astrocytes. An important aspect of the presently demonstrated immunoreactivity of astroglia to mAChR proteins is its labeling in situ instead of in tissue culture. This finding may further support investigation, e.g., on anatomical relations of astroglia with neuronal and vascular elements, and its reactivity in experimental conditions. © 1993 Wiley‐Liss, Inc.