bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oligodendrocytes but not astrocytes express apolipoprotein E after injury of rat optic nerve
Authors: Stoll Guido , Mueller Hans Werner , Trapp Bruce D. , Griffin John W. 
Published: January 2005

AbstractApolipoprotein E (apoE), a lipid‐binding glycoprotein involved in transport and metabolism of phospholipids and cholesterol, is synthesized and secreted at elevated rates following transection of mature rat peripheral and central nerves. In the peripheral nervous system (PNS) infiltrating macrophages express apoE during Wallerian degeneration. Following injury of the optic nerve (ON) apoE synthesis is significantly stimulated but the apoE‐expressing cells have thus far not been identified. This study used 1 μm and thin cryosections to identify the cellular source of apoE in transected ON. Serial 1 μm frozen sections were stained by avidin‐biotin‐peroxidase complex immunocytochemistry by using a specific antiserum to apoE and by antibodies that identify different cell types: glial fibrillary acidic protein (GFAP) for astrocytes, 2′,3′‐cyclic nucleotide‐3′ phosphodiesterase (CNP) for oligodendrocytes, and ED1 for macrophages. In normal ON both astrocytes and oligodendrocytes were apoE‐positive. One week after ON transection oligodendrocytes accounted for the majority of apoE‐positive cells, while apoE immunoreactivity had disappeared from astroglial cell bodies and processes. In contrast to the PNS only a few ED1/apoE‐positive macrophages were present in ON 7 days after transection. By using immunogold‐labeled ultrathin crysections apoE could be localized in the Golgi apparatus of oligodendrocytes, indicating synthesis by these cells. Our data suggest that oligodendrocyte‐derived apoE protein may participate in the redistribution of myelin lipids after CNS injury.
Dissociation of GFAP intermediate filaments in eae: Observations in the lumbar spinal cord
Authors: Eng Lawrence F. , D'Amelio Fernando E. , Smith Marion E. 
Published: January 2005

AbstractAcute experimental allergic encephalomyelitis (EAE) in the Lewis rat is a cell‐mediated autoimmune disease of central nervous system myelin. The lesion has been characterized by breakdown of the blood‐brain barrier, edema, and periventricular infiltration of macrophages and lymphocytes. At the early stage of the disease, the astrocytes show a marked increase in immunostaining for glial fibrillary acidic protein (GFAP). A corresponding increase in GFAP content, however, cannot be demonstrated. Electron microscopic examination of the early lesion shows a typical reactive astrocytic response expressed by an enlarged watery cytoplasm, particularly at the level of the processes surrounding neurons and blood vessels and in the neuropil itself. The astroglial processes contain numerous glycogen particles (aggregates and single particles). Glial filaments are also conspicuous and are arranged in small bundles or loose thin filaments adjacent to the bundles. The glial filaments that normally appear as tight bundles have expanded and appear less dense. We suggest that the increase in GFAP immunostaining of the astrocytes in the early lesion is due in part to edema, which causes dissociation of the filaments and thereby exposes more antigenic sites to the antibodies.
Expression of viral and myelin gene transcripts in a murine CNS demyelinating disease caused by a coronavirus
Authors: Jordan Craig A. , Friedrich Victor L. , Godfraind Catherine , Cardellechio Christine B. , Holmes Kathryn V. , Dubois‐Dalcq Monique 
Published: January 2005

AbstractC57BI/6N mice develop a CNS demyelinating disease when inoculated intracranially at 4 weeks of age with the A59 strain of mouse hepatitis virus (MHV‐A59). In order to explore the virus‐host interactions, the histological features of the demyelinating disease were correlated with the spatial and temporal distribution of viral transcripts and the expression of oligodendrocyte‐specific genes (myelin basic protein, proteolipid protein, myelin‐associated glycoprotein, and 2′, 3′ cyclic nucleotide 3′‐phosphohydrolase) in the spinal cord of diseased mice. Three distinct phases in the disease were identified. In the first phase, 1 week postinfection (1 WPI), virus replication was widespread in both gray and white matter but was preferentially occurring in glial cells. In the ventral and dorsal root zones where viral transcripts were most abundant, all myelin gene transcripts were decreased before demyelination was seen. During the second phase of the disease (2–3 WPI), viral transcripts decreased in abundance and became restricted to the white matter. Numerous demyelinating lesions were observed and were characterized by inflammatory cells, paucity of oligodendrocytes, and a profound decrease of all myelin gene transcripts. In the third phase of the disease (4–6 WPI) no viral transcripts were detected, and remyelination began. In the lesions and the tissue surrounding them, transcripts of all myelin genes increased to levels above normal. The increased expression of myelin gene transcripts occurred in a synchronized manner and with a cellular distribution reminiscent of that seen in developmental myelination. These molecular events correlated with efficient remyelination and clinical recovery in this murine demyelinating disease.
In situ demonstration of mature oligodendrocytes and their processes: An immunocytochemical study with a new monoclonal antibody, Rip
Authors: Friedman B. , Hockfield S. , Black J.A. , Woodruff K.A. , Waxman S.G. 
Published: January 2005

AbstractThis paper introduces “Rip” a monoclonal antibody that produces relatively complete staining of oligodendrocytes and their processes in the adult central nervous system (CNS). The distribution of Rip immunoreactivity coincides with that of myelinated axons in both the spinal cord and the cerebellum. In addition, doubleimmunolabeling experiments demonstrate that Rip stains processes containing myelin basic protein but does not stain processes that express glial fibrillary acidic protein. These results indicate that Rip selectively stains oligodendrocytes but not astrocytes. Moreover, individual Rip‐stained oligodendroglial somata and their cytoplasmic processes were observable at both the light microscopic and electron microscopic level when the staining of myelin was reduced. This was accomplished by omitting detergents from antibody incubation steps. Rip‐stained oligodendrocytes have multiple processes of varying thickness, some of which end in close proximity to myelin sheaths. These immunostained profiles, reminiscent of those observed in oligodendrocytes stained by Golgi methods, are unique to Rip and indicate that its immunoreactivity is distinct from that of existing serological markers for oligodendrocytes.
Glial hyaluronate‐binding protein in Wallerian degeneration of dog spinal cord
Authors: Bignami Amico , Mansour Hussein , Dahl Doris 
Published: January 2005

AbstractWallerian degeneration of spinal cord dorsal columns was produced in three dogs by unilateral extradural dorsal rhizotomy at the lower thoracic level. The spinal cord was studied 1 month, 2 months, and 3 months after surgery. Transverse cryostat sections at the site of rhizotomy and at the mid‐thoracic level were stained by indirect immunofluorescence with antibodies to the glial fibrillary acidic protein (GFAP) and to the glial hyaluronate‐binding protein (GHAP). GHAP immunoreactivity was almost unchanged in the degenerated dorsal column 1 month after rhizotomy. After 2 and 3 months, staining with GHAP antibodies was markedly decreased in the gliosed dorsal column at the site of rhizotomy, but it still persisted at the mid‐thoracic level. It is concluded that GHAP persists for long periods of time in dorsal columns undergoing Wallerian degeneration, a finding consistent with its putative role as a nonpermissive substrate preventing nerve regeneration in CNS white matter.
Expression of high molecular weight astroglial extracellular proteins is altered by growth environment
Authors: Quarless Shelley A. , Lam Dominic M.K. 
Published: January 2005

AbstractConditioned medium from primary rat cortical glia was analyzed with respect to the composition of the secreted high molecular weight protein species. Developmental characteristics of astroglia are affected by growth in the presence and absence of serum. These growth conditions had a pronounced effect on the extracellular protein profile, cellular morphology, and cell substratum adhesion.Cells cultured in defined serumless medium did not express certain proteins expressed in the presence of serum but rather synthesized proteins specifically stimulated by the defined serumless environment. A morphological change from flat amorphous to a contracted fibrous network having an increased affinity for self‐self cellular adhesion rather than adhesion to the surface of the tissue culture dish was also stimulated by the defined serumless medium environment.A comparison of the extracellular proteins secreted by the rat C6 glioma and the rat PC12 cell demonstrated the cell‐specific nature of the primary glial proteins.
Comparative immunohistochemical study of glial filament proteins (glial fibrillary acidic protein and vimentin) in goldfish, octopus, and snail
Authors: Cardone Beatrice , Roots Betty I. 
Published: January 2005

AbstractGlial fibrillary acidic protein (GFAP) and vimentin proteins are known to be component proteins of glial filaments in the CNS of many vertebrates. The nature of the filaments present in the glial cells of the goldfish optic tectum and in the CNS of two members of the Mollusca (Helix pomatia and Octopus vulgaris) were investigated using immunocytochemical localization of monoclonal antibodies to GFAP and vimentin. Immunoblots visualized by the alkaline phosphatase method showed cross‐reactive protein bands to GFAP and vimentin antibodies in total brain homogenates of the goldfish, octopus, and snail. Immunofluorescence staining of the goldfish optic tectum showed GFAP immunoreactivity, primarily in the ependymal cell processes. Immunogold labelling at the ultrastructural level verified that GFAP antibodies were bound to glial filaments. Immunolabelling of the optic lobe of Octopus vulgaris and the cerebral ganglia of Helix pomatia suggests that a protein exhibiting antigenic properties similar to GFAP is a component protein in the filaments of the protoplasmic and filamentous glia randomly distributed throughout the CNS. Unlike anti‐GFAP antibodies, which stained relatively specific to filaments, vimentin staining in the CNS tissues of the three organisms studied did not appear to be exclusive to filamentous structures. As vimentin protein has been shown, in previous studies as well as our own, to exist in many tissue types, this suggests that it does not appear to be confined to glial filaments but is shared with other subcellular components. The proteins GFAP and vimentin which are thought to be well conserved in vertebrate evolution also appear to be expressed in the nervous system of some lower organisms.
Sequence of tissue responses in the early stages of experimental allergic encephalomyelitis (EAE): Immunohistochemical, light microscopic, and ultrastructural observations in the spinal cord
Authors: D'Amelio Fernando E. , Smith Marion E. , Eng Lawrence F. 
Published: January 2005

AbstractExperimental allergic encephalomyelitis (EAE) was induced in adult Lewis rats with purified guinea pig CNS myelin and Freund' adjuvant. As soon as the very earliest clinical signs appeared the animals were perfused with fixatives and the spinal cord analyzed by electron microscopy, silver methods, and immunocytochemistry.Our findings suggest that in the early stages of EAE a sequence of events can be traced, although these events frequently overlap. The earliest morphological change appears to be astrocytic edema in both the cell body and processes. Increased amounts of glycogen particles and dispersion of glial filaments are prominent. These changes seem to occur just prior to the time when inflammatory cells begin to penetrate the capillary walls. Invasion of the neuropil mainly by macrophages and lymphocytes closely follows. Both macrophages and microglia seem to participate in phagocytosis of oligodendrocytes and myelin. Demyelination, however, is not a prominent feature at this early stage.
Neuron–glial interactions involved in the regulation of glutamine synthetase
Authors: Mearow Karen M. , Mill John F. , Freese Ernst 
Published: January 2005

AbstractCocultures of rat cortical astrocytes with cerebellar granule cell neurons, but not a variety of other cell types tested, resulted in an induction of glutamine synthetase (GS) mRNA over the basal levels expressed in pure astrocyte cultures. This induction involved both contact‐ and noncontact‐mediated events and may be a result of astroglial differentiation promoted by interactions with the primary neurons. Astrocytes grown in the presence of the granule neurons (but not the other cell types tested) exhibited a more complex, process‐bearing morphology typical of more differentiated cells. In addition, glial cell proliferation was inhibited not only by the presence of live granule cells, but also by fixed neurons and neuronal membranes. Under the same experimental conditions, GS mRNA was increased (two‐ to threefold) compared with the expression observed in pure astrocyte cultures. Because of the role of GS in glutamate metabolism and the influence of the glutamatergic granule neurons on glial GS mRNA levels, the effect of exogenous glutamate was examined. The addition of 100 μM glutamate to the culture medium resulted in an increase in GS mRNA in the astrocyte cultures similar to that observed in the cocultures, where the addition of glutamate did not further increase GS mRNA levels. These results provide further evidence for the importance of neuron–glial interactions in the regulation of glial gene expression.
Basic fibroblast growth factor (bFGF) and rat C6 glioma cells: Regulation of expression, absence of release, and response to exogenous bFGF
Authors: Westermann Reiner , Unsicker Klaus 
Published: January 2005

AbstractBasic fibroblast growth factor (bFGF) is a potent mitogen for several types of cells, including glial cells, which also seem to express bFGF. We have used rat C6 glioma cells as a model system to study the expression and release of bFGF by glioma cells, as well as the effects of exogenous bFGF on these cells. We have shown that C6 cells, express 18 kD bFGF and several higher molecular weight immunoreactive forms. The expression of bFGF could be induced by a factor present in fetal calf serum. Subsequent to its initial appearance, bFGF is regulated in a cell density‐dependent manner. Neither bFGF‐like immunoreactive material, nor bFGF‐like neurotrophic activity were found to be released by C6 cells. Exogenously applied bFGF changed C6 cell morphology similar to cyclic AMP induced alterations but had no significant influence on C6 cell proliferation and biochemical differentiation. From these results we conclude that bFGF in C6 cells might act as an endogenous (not autocrine) mitogen. Possible roles for bFGF in glial cells are discussed.
Double‐labeling in situ hybridization analysis of mRNAs for carbonic anhydrase II and myelin basic protein: Expression in developing cultured glial cells
Authors: Ghandour M. S. , Skoff R. P. 
Published: January 2005

AbstractWe applied in situ hybridization to analyze the location and the developmental changes in the distribution of the transcripts for carbonic anhydrase II (CAII) and myelin basic protein (MBP) in mouse primary cultured glial cells. Both mRNAs were localized to the oligodendrocyte using double‐labeling in situ hybridization. No evidence for CAII transcripts in astrocytes was obtained, indicating that CAII is expressed only by oligodendrocytes in normal rodent glia. As early as 48 h after plating, CAII and MBP mRNAs are present in a few, small round cells. Message is present 2–4 days before levels of these proteins can be detected in similar primary glial cultures.The intensity of labeling for MBP and CAII mRNA positive cells increases significantly during the second week but then decreases after the end of the third week.Only the oligodendrocyte perikaryon and a few processes are positive during the first week. In contrast, at 14 days, a large number of cell processes in addition to the cell bodies are heavily stained for both mRNAs. Both mRNAs could be detected far away from the cell body, up to 250 μm in some cell processes. Some segments on a cell process accumulate higher levels of mRNA than other areas. These areas may correspond to the accumulation of free ribosomes and to starting points for the membrane sheets elaborated by cultured oligodendrocytes. The developmental profile for timing and distribution of these two messages mimics closely their in situ pattern.
Role of glia in K+ and pH homeostasis in the neonatal rat spinal cord
Authors: Jendelová Pavla , Syková Eva 
Published: January 2005

AbstractStimulation‐evoked transient changes in extracellular potassium ([K+]e) and pH (pHe) were studied in the neonatal rat spinal cords isolated from 3–13‐day‐old pups. In unstimulated pups the [K+]e baseline was elevated and pHe was more acid than that in Ringer's solution (3.5 mM K+, pH 7.3–7.35). The [K+]e and pHe in 3–6‐day‐old pups was 3.91 ± 0.12 mM and pHe 7.19 ± 0.01, respectively, while in 10–13‐day‐old pups it was 4.35 ± 0.15 mM and 7.11 ± 0.01, respectively. The [K+]e changes evoked in the dorsal horn by a single electrical stimulus were as large as 1.5–2.5 mM. Such changes in [K+]e are evoked in the adult rat spinal cord with stimulation at a frequency of 10–30 Hz. The maximal changes of 2.1–6.5 mM were found at a stimulation frequency of 10 Hz in 3–6‐day‐old animals. In older animals the [K+]e changes progressively decreased. The poststimulation K+‐undershoot was found after a single stimulus as well as after repetitive stimulation.In 3–8‐day‐old pups, the stimulation evoked an alkaline shift, which was followed by a smaller poststimulation acid shift when the stimulation was discontinued. In pups 3–4‐days‐old the stimulation evoked the greatest alkaline shifts, i.e., by as much as 0.05 pH units after a single pulse and by about 0.1 pH units during stimulation at a frequency of 10 Hz. In 5–8‐day‐old pups, the alkaline shift became smaller and the poststimulation acid shift increased. Stimulation in 10–13‐day‐old pups produced an acid shift of 0.03–0.07 pH units, which was preceded by a scarcely discernible alkaline shift. MgCl2 (20 mM) reversibly reduced the alkaline but not the acid shifts by 50–60%. Bath application of the carbonic anhydrase inhibitor acetazolamide had no effect on the alkaline shift, while the acid shift decreased by 70–80%. The superfusion of the cord with 10 mM KCl resulted in acid shifts of 0.10–0.14 pH units.We conclude that the [K+]e ceiling level and the character of pHe transients in the spinal cord are closely related to gliogenesis. Our results suggest that glial cells buffer the activity‐related [K+]e increase and alkaline pHe shifts in the extracellular space.
Biochemical and ultrastructural study of glycogen in cultured astrocytes submitted to the convulsant methionine sulfoximine
Authors: Hevor T. K. , Delorme P. 
Published: January 2005

AbstractThe convulsant methionine sulfoximine is a potent glycogenic agent in the central nervous system of rodents in vivo. This investigation was undertaken to look for the basic mechanism underlying this property. Astrocytes were cultivated from newborn rat neopallium and glycogen was studied by both biochemical and ultrastructural methods. When the astrocytes were incubated in a medium containing 5.55 mM glucose, methionine sulfoximine (0.55 mM) induced a significant increase in their glycogen content. Glucose content did not change in astrocytes, but it diminished in the medium in all cases. When the decrease in glucose level in the medium was limited, the same glycogenic effects of methionine sulfoximine were observed, but the glycogen contents were higher. The augmentation of the concentration of the convulsant enhanced its glycogenic effect, but this was not directly dose dependent. When the flat and polygonal astrocytes were transformed into process‐bearing astrocytes by dibutyryl cyclic AMP methionine sulfoximine always induced an increase in glycogen content. In this case, the values of glycogen contents were lower. In electron microscopy, no glycogen particles were present in the astrocytes even after methionine sulfoximine treatment, contrary to the case in vivo. These results show that the convulsant does not need the presence of neuronal cells to induce glycogen accumulation and that astrocytes may be the direct cell targets. The apparent discrepancy between the biochemical and ultrastructural data is probably due to the relatively low concentration of glycogen in cultured astrocytes.
Quisqualate‐induced excitotoxic death of glial cells: Transient vulnerability of cultured astrocytes
Authors: Haas Jitka , Erdö Sándor L. 
Published: January 2005

AbstractThe cytotoxic effect of quisqualate, a potent excitatory amino acid (EAA), was examined in purified astrocyte cultures obtained from neonatal rat cerebral cortex and grown in a serum‐free, defined medium (G5). Excitotoxicity was evaluated by phase contrast microscopy and quantified by the measurement of lactic dehydrogenase (LDH) activity released from the damaged cells into the culture medium. Quisqualate evoked not only osmotic swelling, but also cytotoxic cell death of cultured astrocytes. The vulnerability of cells was restricted to a period between day 4 and 8 in subculture, with a maximal sensitivity on day 7. The present findings indicate that not only neurons, but also glial cells may exhibit excitotoxic vulnerability. The vulnerability to quisqualate appears to be a transient phenomenon, at least in cultured astrocytes.
Glial cell lineages in the neural crest
Authors: Douarin Nicole Le , Dulac Catherine , Dupin Elisabeth , Cameron‐Curry Patrizia 
Published: January 2005

AbstractWe have been studying how and when the different peripheral glial cell lineages individualize during avian embryonic development. Three different and complementary experimental approaches were used for this purpose: (1) the quail/chick chimera system allowed the tracing in vivo of the origin of the various types of peripheral glial cells (Schwann cells of nerves, satellite glial cells of sensory and autonomic ganglia, and enteric glial cells), and the analysis of the non‐neuronal cell population of ganglia; (2) characterisation of early cell‐type specific markers that discriminate between the different glial cell subpopulations; and (3) analysis of the progeny of neural crest cells in clonal cultures. As a result of these approaches, two novel glial‐specific markers, expressed earlier than any previously described myelin components, have been identified and partly characterised. The divergence of glial and neuronal cell lineages is a process that is not completely terminated during the phase of neural crest migration. Whereas some cells are apparently already totally committed to a glial fate at this stage, others retain dual neuronal/glial potentialities.