bluuebunny/crossref_metadata_2025 huggingface dataset:
Laminin and s‐laminin are produced and released by astrocytes, schwann cells, and schwannomas in culture
Authors: Chiu Arlene Y. , Espinosa De Los Monteros A. , Cole Ruth A. , Loera Sofia , De Vellis Jean
Published: January 2005

Components of the extracellular matrix (ECM) have been implicated in the regulation of neuronal migration, axonal growth, and synaptogenesis. We have examined cultures of glial cells, Schwann cells, and schwannomas for the expression of two components of the ECM, laminin and s‐laminin, using immunohistochemical and Western blot techniques. Laminin is a potent promotor of neurite outgrowth in cultures of both central and peripheral neurons, and is present in all ECMs. In contrast, s‐laminin (for synaptic laminin), a recently described homolog of laminin, is highly localized at the neuromuscular synaptic cleft (Sanes and Chiu, Cold Spring Harbor Symp. Quant. Biol. 1983;48:667–678; Chiu and Sanes, Dev. Biol. 1984;103:456–467) and shows selective adhesivity for motor neurons (Hunter et al. Cell 1989;59:905–913). While the distribution of these ECM components have been well documented in situ, the sources of these extracellular molecules are unclear. We report that astrocytes cultured in serum‐free medium maintain an organized ECM that only bears laminin immunoreactivity; s‐laminin appears to be sequestered intracellularly. However, both molecules are found in the astrocyte conditioned medium. Thus, under these growth conditions, astrocytes produce and release laminin and s‐laminin, but only incorporate the former into an ECM. In contrast, neither molecule is present in comparable cultures of oligodendrocytes. Although no established ECM is seen in cultures of Schwann cells or schwannomas, laminin and s‐laminin immunoreactivity are present within cells and in the conditioned media. These results indicate that certain populations of non‐neuronal support cells and cell lines can produce and release both synaptic and extrasynaptic components of the ECM. The assembly of these different molecules into an organized basal lamina may require the presence of additional factors or interaction with neurons.
Gap junctional intercellular communication between cultured ependymal cells, revealed by lucifer yellow CH transfer and freeze‐fracture
Authors: Bouillé Christian , Mesnil Marc , Barriere Helene , Gabrion Jacqueline
Published: January 2005

In order to analyze intercellular communication between ependymal cells in mammalian brain, we have studied gap junctional communication of ependymal and glial cells in long term primary cultures derived from fetal mouse or rat hypothalamus and choroid plexus obtained in serum supplemented media with two complementary methods: (1) dye transfer of Lucifer Yellow CH after intracellular microinjection of the different cellular types, and (2) freeze‐fracture of the same cultured ependymal cells. In our culture conditions, we have shown that the GJIC capacity to transfer dye was very different according to cellular types microinjected with Lucifer Yellow CH in the following respects: (1) in ependymal cells, GJIC was always important: ciliated ependymal cells, which are numerous in hypothalamic ependymal cultures (10–120 coupled cells), choroidal ependymocytes in plexus cultures (15–250 coupled cells), and non‐choroidal ependymocytes in diencephalic roof cultures (10–30 coupled cells), and (2) in astroglial cells found in these primary cultures, no GJIC was observed in spite of the presence of well‐differentiated gap junctions revealed by freeze‐fracture replicas. All these results show a strong GJIC in ependymal cells and indicate the very good functional state of these cells in vitro.
Assembly, disassembly, and exchange of glial fibrillary acidic protein
Authors: Nakamura Yu , Takeda Masatoshi , Angelides Kimon J. , Tada Kunitoshi , Hariguchi Shiro , Nishimura Tsuyoshi
Published: January 2005

The kinetics and dynamics of glial fibrillary acidic protein (GFAP) assembly was explored by a fluorescence energy transfer assay method. Purified GFAP was stoichiometrically labeled at a single cysteine residue with fluorescein‐maleimide. Soluble labeled GFAP in a low ionic strength buffer was assembled into 10 nm filaments by rapidly increasing the ionic strength, and the kinetics of GFAP assembly was monitored by the reduction in fluorescence due to self‐quenching of fluorescein. The extent of fluorescence quench correlated with both the formation of 10 nm filament morphology and the amount of protein pelleted at 12,000g. The assembly of GFAP is critically dependent upon both protein and magnesium ion concentration, and at the critical concentration for GFAP assembly is ∼ 40 μg/ml. Disassembly of GFAP filaments was also observed as a relief of fluorescence quenching after dilution of labeled GFAP filaments. When labeled GFAP filaments were mixed with an excess of unlabeled filaments, a rapid increase of fluorescence was observed, which is due to an exchange of subunits between labeled and unlabeled GFAP filaments. These results indicate that GFAP filaments are dynamic structures and that a small pool of kinetically active unassembled GFAP subunits are in a dynamic equilibrium with assembled GFAP filaments. The ability of GFAP to assemble, disassemble, and undergo subunit exchange has important implications for the organization and dynamics of astroglia cell cytoskeleton during development and in response to injury.
Enteric glia
Authors: Gershon Michael D. , Rothman Taube P.
Published: January 2005

The structure of the enteric nervous system (ENS) is different from that of extraenteric peripheral nerve. Collagen is excluded from the enteric plexuses and support for neuronal elements is provided by astrocyte‐like enteric glial cells. Enteric glia differ from Schwann cells in that they do not form basal laminae and they ensheath axons, not individually, but in groups. Although enteric glia are rich in the S‐100 and glial fibrillary acidic proteins, it has been difficult to find a single chemical marker that distinguishes enteric glia from non‐myelinating Schwann cells. Nevertheless, two monoclonal antibodies have been obtained that recognize antigens that are expressed on Schwann cells (Ran‐1 in rats and SMP in avians) but not enteric glia. Functional differences between enteric glia and non‐myelinating Schwann cells, including responses to gliotoxins and in vitro proliferative rates, have also been observed. Developmentally, enteric glia, Schwann cells, are derived from the neural crest. In both mammals and birds the precursors of the ENS appear to migrate to the bowel from sacral as well as vagal levels of the crest. These crest‐derived emigrés give rise to both enteric glia and neurons; however, analyses of the ontogeny of the enteric innervation in a mutant mouse (the ls/ls), in which the original clolonizing waves of crest‐derived precursor cells are unable to invade the terminal colon, suggest that enteric glia can also arise from Schwann cells that enter the gut with the extrinsic innervation. When induced to leave back‐transplanted segments of avian bowel, enteric crest‐derived cells migrate into peripheral nerves and form Schwann cells. Enteric glia and Schwann cells thus appear to be different cell types, but ones that derive from lineages that diverge relatively late in ontogeny.
Astroglia in CNS injury
Authors: Hatten Mary E. , Liem Ronald K. H. , Shelanski Michael L. , Mason Corol A.
Published: January 2005

The astroglial response to CNS injury is considered in the context of neuron‐glial relationships. Although previous models suggested that astroglial cells present in “scars” impede axon regrowth owing to irreversible changes in the glial cell following injury, recent in vivo and in vitro studies indicate that astroglial cells exhibit considerable plasticity, elevating expression of the glial filament protein and altering expression of properties which support axons, including extracellular matrix components and cell surface adhesion systems. Both in vivo and in vitro studies on neuron‐glia interactions in different brain regions suggest that glia express region‐specific properties, including ion channels, neurotransmitter uptake and receptor systems, and cell surface adhesion systems. Together these findings suggest that a more detailed analysis of glial response to injury in different brain regions will lead to an appreciation of the diversity of the astroglial response to injury, and its regulation by neuron‐glia relationships.
Diversification of glial lineages: A novel method to clone brain cells in vitro on nitrocellulose substratum
Authors: Carnow Thomas B. , Barbarese Elisa , Carson John H.
Published: January 2005

We have developed a novel in vitro method to analyze the diversification of glial cells during development. The primary advantage of the approach is that glial lineages are formed in discrete clones on a nitrocellulose substratum where the relationship of the progeny is strictly defined. This method facilitates the comparison of a large complement of astrocyte and oligodendrocyte lineages under controlled conditions. Clones were formed by plating a brain dissociate on nitrocellulose at very low density (5,000–40,000 cells/154 mm2). However, growth depended on diffusible factors produced by brain cells growing under the nitrocellulose support at high density (feeder layer). The cloning efficiency of cells from mouse forebrain (P0) was 1–3%. This means we can detect 100,000 to 300,000 clonal progenitors in the dissociate (107 cells per forebrain) using the clonal culture technique. Cell phenotypes were determined by immunocytochemical staining with anti‐glial fibrillary acidic protein (GFAP) to label astrocytes and anti‐galactocerebroside (GC) and anti‐myelin basic protein (MBP) to label oligodendrocytes. There was a remarkable diversity of glia represented in different lineages. The number of astrocyte clones was greater than the number of oligodendrocyte clones but combined their total was 90%. Clone sizes were distributed over a wide range, which indicated that growth rates varied. Clones appeared compact or dispersed but astrocyte clones exhibited three different morphologies—fibroblast‐like, stellate, and elongated. Oligodendrocytes had different morphologies distinct from astrocytes. Although there were different glial lineages the cells in most clones were homogeneous, indicating the progeny had the same fate. However, a small number of the clones, approximately 2%, were heterogeneous and contained both astrocytes and oligodendrocytes. The application of this technique to glial lineages demonstrates that intrinsic factors have a role in determining cell fate since different clones formed under the same external conditions. Finally, these results are consistent with the existence of multiple glial progenitors or the continued presence of multipotential progenitors at the time of birth.
DBcAMP effect on the expression of GFAP and of its encoding mRNA in astroglial primary cultures
Authors: Le Prince G. , Fages C. , Rolland B. , Nunez J. , Tardy M.
Published: January 2005

Short term and chronic dBcAMP effects on the expression of glial fibrillary acidic protein (GFAP) in astroglial primary cultures are investigated. Short (48 h) and long (more than 7 days) treatments with the cAMP derivative induce both cell shape changes and an increase in GFAP immunolabelling. Such effects are only associated with an increase in GFAP and in GFAP‐mRNA levels in the long term treatment. These results suggest that the short term effect of dBcAMP induces post‐translational modifications of the protein whereas the long term effect is associated with an increase in GFAP mRNA transcription and/or stability.
FGFs stimulate IGF binding protein synthesis without affecting IGF synthesis in rat astroblasts in primary culture
Authors: Loret Camille , Janet Thierry , Labourdette Gérard , Schneid Hélène , Binoux Michel
Published: January 2005

The production of insulin‐like growth factor (IGF)‐I and ‐II and their binding proteins (BPs) has been studied in new‐born rat astroblasts at confluency in primary culture.

Under the influence of fibroblast growth factors (FGFs) (acidic and basic), the morphology of the astroblasts was altered, 125I‐deoxyuridine incorporation was increased, and glutamine synthetase activity was stimulated. IGF production and IGF mRNA expression remained unchanged. Production of the 32 kDa BP (IGFBP‐2), the sole or predominant form under base‐line conditions, was enhanced and the 43–39 kDa form (IGFBP‐3) appeared or were increased. Epidermal growth factor (EGF) also stimulated production of these BPs, whereas thrombin and db‐cAMP had no effect.

Our data suggest that a relationship exists between FGF‐induced maturation of astroblasts and the forms of BP they produce. The data also indicate that some factors may act specifically on BP synthesis, without affecting IGF synthesis, and in this way play a role in regulating the bioavailability of the IGFs.
Platelet‐derived growth factor is mitogenic for O‐2Aadult progenitor cells
Authors: Wolswijk Guus , Riddle Peter N. , Noble Mark
Published: January 2005

We report that platelet‐derived growth factor (PDGF) is a potent mitogen for oligodendrocyte type‐2 astrocyte (O‐2A) progenitor cells derived from the optic nerves of adult rats. Moreover, O‐2Aadult progenitors cultured in PDGF express the range of properties we have described previously for O‐2Aadult progenitors cultured in the presence of type‐1 astrocytes. Similarly, previous studies have demonstrated that PDGF is able to mimic the influence of type‐1 astrocytes on O‐2Aperinatal progenitors. Specifically, O‐2Aadult progenitors and O‐2Aperinatal progenitors exposed to PDGF express differences in average cell cycle time (59 ± 5 h for O‐2Aadult progenitors versus 20 ± 6 h for O‐2Aperinatal progenitors), average rate of migration (4.1 ± 0.6 μm h−1 versus 24.6 ± 5.4 μm h−1), morphology (unipolar versus bipolar), and antigenic phenotype (04+ vimentin− versus 04− vimentin+). Thus, our present results indicate that a single signalling molecule secreted by type‐1 astrocytes produces markedly different cellular behaviours in two related O‐2A progenitor populations.
Schwann cell plasminogen activator is regulated by neurons
Authors: Clark Mary Blair , Zeheb Ron , White Tracy Keith , Bunge Richard P.
Published: January 2005

The synthesis and release of plasminogen activators (PAs) in co‐cultures of embryonic rat dorsal root ganglion nerve cells (NCs) and Schwann cells (SCs) were examined by metabolic labeling, immunoprecipitation, immunodepletion, SDS‐PAGE, zymography, and a two‐step esterolytic assay. Metabolic labeling of SC cultures followed by immunoprecipitation of the conditioned medium (CM) demonstrated that cultured SCs synthesized and released tissue type PA (tPA). Failure of amilioride to inhibit PA activity in SCCM indicated that urokinase PA (uPA) was unlikely to contribute significantly to PA activity in SCCM. Experimental manipulation of the NCs and SCs suggested that NCs regulated SC derived PA. Total PA activity increased in SCCM 10–14‐fold by 6 days after removal of NCs. Multiple molecular weight forms of PAs were detected by SDS‐PAGE followed by zymography. A PA ∼95 kDa was absent in co‐cultures of SCs + NCs but prominent by 4 days postdenervation; PA ∼50–70 kDa increased through 8 days postdenervation and PA ∼25 kDa, present in SC + NC cultures, was absent 8 days after removal of NCs. Upon reintroduction of NCs to denervated cultures (SCs), the pattern of PAs detected in culture medium was transitional between innervated and denervated cultures. Immunodepletion experiments using conditioned medium from denervated SC cultures indicated that various molecular weight forms of PA detected in SCCM by zymography were immunologically related to tPA. These studies demonstrate that SCs synthesized and released tPA in a tissue culture model of peripheral nerve and that one mechanism for regulation of PA released by SCs was by association with NCs. This regulation occurred in cultures of both myelinating and nonmyelinating Schwann cells and thus was not dependent on the state of myelination.
Quantitative immunohistochemical and biochemical correlates of connexin43 localization in rat brain
Authors: Nagy J. I. , Yamamoto T. , Sawchuk M. A. , Nance D. M. , Hertzberg E. L.
Published: January 2005

We have shown by immunohistochemical methods that the gap junction protein connexin43 is heterogeneously distributed in rat brain (Yamamoto et al: J Comp Neurol 302:853, 1990). Here we have compared quantitatively the relative amount of connexin43 detected on Western blots of seven central nervous system (CNS) regions with the density of connexin43‐immunoperoxidase reactivity in these regions. As has been observed on Western blots of several cell types, homogenates of these CNS regions contained two forms of connexin43, its dephospho form with an apparent mobility of ∼41 kDa and its ∼3 kDa phosphorylated form. While the relative quantities of connexin43 varied considerably among the brain regions, the ratio of the 43/41 kDa forms, 0.71, was relatively uniform (correlation coefficient, r = 0.92). Sections of brain processed for connexin43‐immunolocalization by the peroxidase–antiperoxidase (PAP) method showed that chromogen deposition was linear with incubation time in reaction medium. Optical density of tissue connexin43‐immunoreactivity in each of the seven areas plotted against the density of connexin43 bands on Western blots gave a correlation coefficient of r = 0.90. Connexin43‐immunoreactivity had a similar appearance in sections processed by PAP or immunofluorescense procedures and consisted of isolated or aggregates of puncta. For the brain regions examined we conclude: (1) that although total levels of connexin43 vary widely, the levels of its phosphorylated and non‐phosphorylated forms are held in fairly constant proportion; (2) that there is a high correlation between the relative amounts of connexin43 detected biochemically and the density of connexin43‐immunostaining in tissue sections; and (3) that immunohistochemical staining for connexin43 reflects the relative amounts of connexin43 and possibly the numbers of gap junctions present in individual brain areas.
Prenatal exposure to ethanol alters plasma membrane glycoproteins of astrocytes during development in primary culture as revealed by concanavalin a binding and 5′‐nucleotidase activity
Authors: Renau‐Piqueras Jaime , Guerri Consuelo , Burgal Maria , De Paz Paulino , Saez Rosana , Mayordomo Fernando
Published: January 2005

We have investigated the effect of prenatal exposure to ethanol on the extent of binding and surface distribution of the lectin concanavalin A (con A) on rat cortical astrocytes during the periods of proliferation and differentiation in primary culture. The enzymatic activity of the plasma membrane glycoprotein 5′‐nucleotidase was also assessed. The cells were obtained from control fetuses (no exposure to ethanol) and from fetuses prenatally exposed to ethanol.

The main findings were: (1) both proliferating and differentiating control astrocytes showed two distinct types of surface con A receptors that could correspond to high‐ and low‐affinity binding sites; (2) the extent of con A binding was greater in mature than in proliferating control cells; (3) the distribution of con A on cell surface components changed with differentiation; (4) the activity of 5′‐nucleotidase showed a substantial increment during the period of differentiation; and (5) prenatal exposure to ethanol clearly decreased the ability of astrocytes to bind con A, altered the surface distribution of the receptors for this lectin, and decreased the activity of 5′‐nucleotidase. These effects were more marked in proliferating cells.

In conclusion, it is shown that the extent of con A labeling and the activity of 5′‐nucleotidase in astrocytes are dependent on the stage of cell differentiation and that prenatal exposure to ethanol alters the plasma membrane structure of these cells during development.
Spontaneous changes in intracellular calcium concentration in type I astrocytes from rat cerebral cortex in primary culture
Authors: Fatatis Alessandro , Russell James T.
Published: January 2005

Measurement of fura‐2 fluorescence in type I astrocytes from rat cerebral cortex showed that the intracellular calcium ion concentration undergoes very large spontaneous changes. These spike‐like changes ranged from resting levels of calcium of 50–250 nM to as high as 1–2 μM. The spikes were found to be irregular in frequency and amplitude and were frequently synchronous in confluent cultures. The synchronous events appeared as propagating waves that spread over many cells. The spontaneous spikes persisted when the extracellular calcium concentration was reduced to below micromolar levels suggesting that the source for the increases in [Ca2+]i was intracellular. Treatment of the astrocytes with tetrodotoxin did not abolish the spontaneous changes, nor did blockade of voltage‐dependent calcium channels with nimodipine and D‐600. Ryanodine, a blocker of the sarcoplasmic reticulum calcium‐induced calcium release channel, was also without effect. These changes in [Ca2+]i were different in character from both agonist‐induced oscillations and depolarization‐induced increases in intracellular calcium concentration. Depolarization using 25–100 mM [K+]o resulted in a prompt rise in intracellular calcium concentration, which returned to near resting levels, and this response was sensitive to removal of extracellular calcium and voltage‐gated calcium channel antagonists. L‐glutamate (0.5–100 μM) caused large increases in [Ca2+]i that were associated with discrete periodic oscillations in some cells. The cellular trigger for the spontaneous spikes is currently not understood. We conclude that spontaneous changes in [Ca2+]i in astrocytes are distinct from agonist‐induced and membrane potential depolarization‐induced changes.
Uptake of [3H]serotonin and [3H]glutamate by primary astrocyte cultures. I. Effects of different sera and time in culture
Authors: Kimelberg H. K. , Goderie S. K. , Conley P. A. , Higman S. , Goldschmidt R. , Amundson R. H.
Published: January 2005

Na+‐dependent, fluoxetine‐sensitive high‐affinity uptake of serotonin and Na+‐dependent uptake of glutamate were studied in primary astrocyte cultures from 1‐day‐old rat neocortex. This uptake was independent of time in culture from 1 to 6 weeks. High‐affinity serotonin uptake was decreased when cells were grown in horse serum as compared to fetal bovine serum and was almost absent when cells were grown in chemically defined medium. In contrast, glutamate uptake was unaffected by the composition of the medium in which the cultures were grown. The serum effect on serotonin uptake was not due to the greater level of serotonin in the fetal bovine serum and was only reversed by a change of serum over a time period of days. © 1992 Wiley‐Liss, Inc.
PDGF increases the expression of fos and jun in newly formed oligodendrocytes that have become resistant to the mitogenic effect of PDGF
Authors: Hart I. K. , Richardson W. D. , Raff M. C.
Published: January 2005

Bipotential glial (O‐2A) progenitor cells give rise to oligodendrocytes on a predictable schedule in the developing rat optic nerve. The loss of mitotic responsiveness to platelet‐derived growth factor (PDGF) that is seen when O‐2A progenitor cells initially differentiate into oligodendrocytes seems to reflect blocks or deficiencies downstream to some of the early intracellular signalling events induced by PDGF. Here we show that PDGF increases the expression of the Fos and Jun nuclear proteins in newly formed oligodendrocytes in vitro, suggesting that at least one intracellular signalling pathway to the nucleus is activated by PDGF in these cells even though they do not synthesize DNA in response to PDGF. © 1992 Wiley‐Liss, Inc.
5′‐Nucleotidase immunoreactivity of perineuronal microglia responding to rat facial nerve axotomy
Authors: Schoen S. W. , Graeber M. B. , Kreutzberg G. W.
Published: January 2005

The ecto‐enzyme 5′‐nucleotidase was localized immunocytochemically in the axotomized rat facial nucleus. As revealed by the monoclonal antibody 5N4–2,5′‐nucleotidase immunoreactivity markedly increased on perineuronal microglia during the first week following axotomy, and gradually disappeared from these cells by the end of the third post‐operative week. Interestingly, parenchymal microglia were not or only weakly stained. These findings indicate that 5′‐nucleotidase 5N4‐2‐immunoreactivity may serve as a marker for perineuronal microglia, a population of satellite glial cells that appear to be actively engaged in lesion‐induced synaptic changes during regeneration. © 1992 Wiley‐Liss, Inc.
Development and differentiation of glial precursor cells in the rat cerebellum
Authors: Levine Joel M. , Stincone Francis , Lee Ying‐Shuan
Published: January 2005

The development and differentiation of bipotential glial precursor cells has been studied extensively in tissue culture, but little is known about the distribution and fate of these cells within intact animals. To analyze the development of glial progenitor cells in the developing rat cerebellum, we utilized immunofluorescent, immunocytochemical, and autoradiographic techniques. Glial progenitor cells were identified with antibodies against the NG2 chondroitin‐sulfate proteoglycan, a cell‐surface antigen of 02A progenitor cells in vitro, and the distribution of this marker antigen was compared to that of marker antigens that identify immature astrocytes, mature astrocytes, oligodendrocyte precursors, and mature oligodendrocytes.

Cells expressing the NG2 antigen appeared in the cerebellum during the last 3‐4 days of embryonic life. Over the first 10 days of postnatal life, the NG2‐labeled cells incorporated 3H‐thymidine into their nuclei and their total number increased. At all ages examined, the NG2‐labeled cells did not contain either vimentin‐like or glial fibrillary acidic protein (GFAP)‐like immunoreactivity, suggesting that they do not develop along an astrocytic pathway. NG2‐labeled cells of embryonic animals expressed GD3 ganglioside antigens, a property of oligodendrocyte precursors, whereas NG2‐positive cells of postnatal animals did not express GD3 immunoreactivity. Nevertheless, the NG2‐labeled cells of the nascent white matter expressed oligodendrocyte‐specific marker antigens. Cells lyingoutside of the white matter continued to express the NG2 antigen. In adult animals, the NG2‐labeled cells incorporated 3H‐thymidine. Glial cells isolated from adult animals and grown in tissue culture express the NG2 antigen and display the phenotypic plasticity characteristic of 02A progenitor cells. These findings demonstrate that a population of glial progenitor cells is extensive within both young and adult animals.
Cell type‐specific regulation of major histocompatibility complex (MHC) Class I gene expression in astrocytes, oligodendrocytes, and neurons
Authors: Massa Paul T. , Ozato Keiko , McFarlin Dale E.
Published: January 2005

Mechanisms of major histocompatibility complex (MHC) class I gene regulation in cells of the CNS have been studied in vitro. Astrocytes in primary cultures, but neither oligodendrocytes nor neurons, constitutively expressed cell surface MHC class I molecules. Interferon‐gamma (IFN‐γ) treatment led to induction of MHC class I expression in astrocytes and oligodendrocytes but not in neurons. The conserved up‐stream sequence containing the juxtaposed nuclear factor (NF)‐kB‐like region I and IFN‐response consensus sequence (ICS) constitutively enhanced MHC class I gene promoter activity in astrocytes, but not in oligodendrocytes or in neurons. Nuclear extracts from astrocytes, but not from oligodendrocytes and neurons, had a binding activity specific for the NF‐kB‐like region I sequence, indicating that constitutive expression of MHC class I genes is governed by the upstream region I enhancer and its binding factor. IFN‐γ treatment led to induction of MHC class I promoter activity in astrocytes and oligodendrocytes, but not in neurons. In accordance with this observation, a nuclear factor that binds to the ICS was induced in astrocytes and oligodendrocytes but not in neurons following IFN‐γ treatment. This study illustrates cell type‐specific regulation of MHC class I genes in the CNS that correlates with the expression of DNA binding factors relevant to MHC class I gene transcription. © 1993 Wiley‐Liss, Inc.
Receptor‐mediated phospholipase D activity in primary astroglial cultures
Authors: Gustavsson Lena , Lundqvist Christofer , Hansson Elisabeth
Published: January 2005

Phospholipase D, an enzyme involved in signal transduction cascades, catalyses the formation of phosphatidic acid and, when ethanol is present, the formation of phosphatidylethanol. In the present study we demonstrate that stimulation of muscarinic acetylcholine receptors as well as P2‐purinergic receptors induces activation of phospholipase D in primary cultures of astroglial cells. Both the hydrolysis and the transphosphatidylation reactions were stimulated by receptor agonists. Carbachol and ATP induced a rapid increase in the amount of [3H]phosphatidic acid in astroglial cells prelabelled with [3H]oleic acid. When ethanol (150 mM) was present, phosphatidylethanol was formed. Furthermore, the receptor‐mediated increase in the concentration of phosphatidic acid was inhibited by ethanol, indicating that the phosphatidic acid production was indeed mediated by phospholipase D. The formation of phosphatidylethanol was concentration dependent, with a half‐maximal effective concentration of 5 × 10−5 M for carbachol and 10−5 M for ATP. The carbachol‐induced response was almost completely inhibited by atropine, indicating activation of phospholipase D via muscarinic receptors. The purinergic response is most probably mediated via P2‐receptors since ADP was almost as efficient as ATP in inducing phosphatidylethanol formation, whereas AMP was significantly less potent. We conclude that astroglial cells in primary culture display muscarinic and purinergic receptors coupled to phospholipase D. The relationship to cell function needs to be further investigated. © 1993 Wiley‐Liss, Inc.
Increase of intracellular calcium induced by oxytocin in hypothalamic cultured astrocytes
Authors: Di Scala‐Guenot Dominique , Mouginot Didier , Strosser Marie‐Thérèse
Published: January 2005

A recent study demonstrated oxytocin (OT) receptors on hypothalamic cultured astrocytes (Di Scala‐Guenot and Strosser, 1992). The attempt in the present paper was to determine a possible intracellular calcium mobilization induced by OT receptor activation in these cells. Using the microspectrofluorimetric technique with fura‐2 as calcium indicator, brief applications of OT on single astrocytes induced a transient and reversible dose‐dependent increase of intracellular calcium concentration ([Ca2+]i) in most of the cells tested. In a few cells, OT application triggered intracellular calcium oscillations. Repetitive applications of OT generally produced a decreasing calcium signal, suggesting a desensitization of the receptor. OT‐induced calcium release was prevented by a prior or simultaneous application of an OT antagonist. The origin of the calcium mobilization was assessed during conditions where no extracellular calcium was available. Neither removal of extracellular calcium nor addition of a calcium channel blocker, cadmium 100 μM, in the bathing solution, did affect the calcium response to OT, demonstrating that release of intracellular calcium is solely involved in the OT‐induced [Ca2+]i increase. The OT‐induced calcium mobilization was abolished after thapsigargin application (100 nM). This indicates that the calcium response to OT application was principally associated with activation of the IP3‐sensitive calcium stores. Taken together these results demonstrate that OT receptors previously detected on hypothalamic cultured astrocytes are functional receptors which transduction pathways involve calcium mobilization from IP3‐sensitive stores. © 1994 Wiley‐Liss, Inc.
The community clinic — its advantages and disadvantages
Authors: Benbow Susan Mary
Published: January 2005

A traditional hospital outpatient clinic for the follow‐up of patients with mental illness in old age was replaced by home visits (the community clinic). As a preliminary study, the first six community clinics were compared with six outpatient clinics and found to be superior on several practical measures (including the percentage of booked patients who were successfully seen and the number of carers seen) as well as in terms of information obtained. The DHSS does not monitor this activity but it is an important development of specialist services for the elderly mentally ill.
Notes from ancient Egypt
Authors: Loza Nasser , Milad Georges
Published: January 2005

This article highlights the fascinating glimpses of old age provided by studying the medical and religious manuscripts of Ancient Egypt.
Late‐onset paranoia: Distinct from paraphrenia?
Authors: Flint Alastair J. , Rifat Sandra L. , Eastwood M. Robin
Published: January 2005

Using Kraepelin's distinction between paraphrenia and paranoia, 21 patients with late paraphrenia were compared with 12 with late‐onset paranoia. The paranoia group had significantly more clinically unsuspected (silent) cerebral infarction on CT brain scan and was less responsive to antipsychotic medication. The results suggest that cerebral organicity, especially stroke, is an important risk factor for late‐onset paranoia and may contribute to a relatively poor prognosis.
Late paraphrenia and ICD 10
Authors: Quintal Marie , Day‐Cody Diana , Levy Raymond
Published: January 2005

As part of a field study of the latest draft of WHO'S ICD 10 classification, two clinicians, one familiar with ICD 9 and one with DSM‐111, rated 36 cases previously diagnosed as ‘late paraphrenia’ using ICD 9. When raters adhered closely to the diagnostic guidelines issued with the new classification, complete agreement was achieved and most cases received a diagnosis of paranoid schizophrenia. However, both raters were uncomfortable with the low threshold for this diagnosis and when freed from the need to give primacy to schizophrenia preferred a much wider range of diagnoses which included a number of subcategories of delusional disorder. ‘Persistent delusional disorder’ and ‘other persistent delusional disorder’ produced the best fit but up to eight cases were given two diagnoses. Levels of confidence in the diagnosis and ease of achieving this are also given. There was an acceptable level of agreement (kappa = 0.756) when this procedure was employed. It is argued that retrieval of such cases would be facilitated either by providing a code for age of onset or by restoring a separate category for late onset schizophrenia or late paraphrenia.
Human brain metabolic responses to familiarity during lexical decision
Authors: Nenov Valeriy I. , Halgren Eric , Mandelkern Mark , Smith Michael E.
Published: January 2005

Local cerebral glucose metabolic rate was measured using F18‐DG/PET in 11 normal righthanded male volunteers performing two versions of a visual lexical decision task differing only with respect to whether the stimuli were all novel and shown only once, or whether they were all repeated many times. Each subject was also scanned in a resting state (eyes open and ears unplugged). Scalp recordings of cognitive evoked potentials in the same subjects and tasks confirmed that the effects of familiarity were present during the entire 30 min FDG uptake period. The N4 (a left temporoparietal negativity 400 ms after stimulus onset) decreased with repetition, and the P3b (a 600 ms latency parietal positivity) increased. The pattern of metabolic activation was also significantly different between the three experimental conditions. Planned comparisons of the tasks with the resting condition revealed significant relative activations of visual and motor areas. Novel words evoked significantly greater activation in the left and right anterior cingulate gyri and right hippocampal formation than did repeated words in the same task. Relative glucose metabolism in the left angular gyrus was significantly greater to novel words than to resting. Thus, two tasks equated in sensory, motor, and decision processes, but differing in the familiarity of the stimuli, evoke significantly different patterns of brain activation. The patterns observed provided evidence that recent episodic memory for words engages a system that includes the bilateral anterior cingulate gyri, the medial temporal lobe, and the left angular gyrus. © 1994 Wiley‐Liss, Inc.
Combined loss of orphan receptors PXR and CAR heightens sensitivity to toxic bile acids in mice
Authors: Uppal Hirdesh , Toma David , Saini Simrat P.S. , Ren Songrong , Jones Thomas J. , Xie Wen
Published: January 2005

Efficient detoxification of bile acids is necessary to avoid pathological conditions such as cholestatic liver damage and colon cancer. The orphan nuclear receptors PXR and CAR have been proposed to play an important role in the detoxification of xeno- and endo-biotics by regulating the expression of detoxifying enzymes and transporters. In this report, we showed that the combined loss of PXR and CAR resulted in a significantly heightened sensitivity to bile acid toxicity in a sex-sensitive manner. A regimen of lithocholic acid treatment, which was tolerated by wild-type and PXR null mice, caused a marked accumulation of serum bile acids and histological liver damage as well as an increased hepatic lipid deposition in double knockout males. The increased sensitivity in males was associated with genotype-specific suppression of bile acid transporters and loss of bile acid–mediated downregulation of small heterodimer partner, whereas the transporter suppression was modest or absent in females. The double knockout mice also exhibited gene- and tissue-specific dysregulation of PXR and CAR target genes in response to PXR and CAR agonists.
In conclusion,

although the cross-regulation of target genes by PXR and CAR has been proposed, the current study represents

in vivo

evidence of the combined loss of both receptors causing a unique pattern of gene regulation that can be translated into physiological events such as sensitivity to toxic bile acids. (Hepatology 2005;41:168–176.)
Nimodipine decreases calcium action potentials in rabbit hippocampal CA1 neurons in an age‐dependent and concentration‐dependent manner
Authors: Moyer James R. , Disterhoft John F.
Published: January 2005

Intracellular recordings were made from rabbit hippocampal CA1 neurons in vitro using slices from aging and young adult rabbits. Calcium action potentials were studied in the presence of 4 μm tetrodotoxin using electrodes filled with 2M CsCl. Increasing concentrations of the dihydropyridine L‐type calcium channel antagonist nimodipine were tested on the amplitude and time course of calcium action potentials. The calcium action potential (AP) consisted of two components: an initial fast phase followed by a slower plateau phase. No difference in the peak amplitude of the initial fast phase was observed between age groups. The amplitude and duration of the slower plateau phase of the calcium AP was significantly larger in aging neurons. Switching to a zero Ca2+ medium in the presence of 200 μm CdCl2 completely blocked the calcium AP. Nimodipine decreased the plateau phase of the calcium AP at concentrations as low as 100 nm in aging neurons and 10 μm in young neurons. Switching to higher concentrations of nimodipine did not reveal any substantially increased block of the calcium AP plateau phase. These data suggest that enhanced calcium influx through L‐type calcium channels is largely responsible for the enhanced calcium action potentials observed in aging CA1 neurons. The action of nimodipine in reducing the plateau phase of the calcium action potential may underlie the drug's notable ability to improve learning in hippocampally dependent tasks in aging animals.
Hippocampus of the domestic pig: A stereological study of subdivisional volumes and neuron numbers
Authors: Holm Ida E. , West Mark J.
Published: January 2005

With the aim of establishing a quantitative structural basis for comparative and experimental studies, the volumes of the hippocampal subdivisions and the total number of neurons in each subdivision were estimated in domestic pig brains using modern stereological techniques. In addition to a detailed description of the stereological methods used in the analysis, comprehensive descriptions of the architectonic boundaries of the subdivisions are included. The absolute and relative volumes of the subdivisions were compared to those of a number of other species and the relationship between the number of neurons and the volume of the subdivisions was compared to that in homologous subdivisions of laboratory rats and humans. The methodology used to estimate the volumes and the total number of neurons in the individual subdivisions were evaluated with regard to the sensitivity that they can provide in experimental studies.
Comparative studies of food‐storing, memory, and The hippocampal formation in parids
Authors: Clayton Nicky S.
Published: January 2005

Birds which scatter‐hoard large numbers of food items such as marsh tits Parus palustris, use memory to retrieve their caches and have an enlarged hippocampal formation relative to the rest of the telencephalon compared with species that store little or no food. Preliminary observations suggested that captive blue tits, P. caeruleus, may store small quantities of food albeit in limited amounts. This experiment compared food‐storing intensity, memory for cache sites, and relative hippocampal formation in marsh tits and blue tits. Comparisons were made both within species, by comparing wild‐caught adults and hand‐raised juvenile blue tits that store and those that do not, and between closely related species, by comparing food‐storing adult wild‐caught blue tits and juvenile hand‐raised blue tits with adult wild‐caught marsh tits. Food‐storing blue tits stored fewer seeds than did marsh tits, and they had a less accurate memory for cache sites and a smaller absolute and relative hippocampal formation than did marsh tits. For further analysis, the hippocampal volume was divided into a rostral (front) portion and a caudal (rear) portion, separated by the first appearance of the anterior commissure. Marsh tits had both larger rostral and caudal portions than did blue tits, but the species difference in hippocampal volume was greater for the rostral than for the caudal portion. In blue tits, wild‐caught adults had significantly larger absolute and relative hippocampal volumes than did hand‐raised juveniles, but there was no difference in the proportion of rostral to caudal portions, irrespective of whether they had stored and retrieved food. Although food‐storing blue tits did not differ from non‐storing blue tits in total absolute or relative hippocampal volume, they had larger rostral portions of the hippocampal formation and small caudal portions. Possible reasons for this area discussed. © 1995 Wiley‐Liss, Inc.
Effects of lormetazepam and other benzodiazepine receptor ligands on car driving‐related skills
Authors: Willumeit H.‐P. , Ott H. , Kuschel Chr.
Published: January 2005

Adequate car driving ability is essential for accident avoidance. Driving ability means the capability of the driver to keep a technically safe vehicle on a safe road without accident and free of danger to himself and to other traffic participants. Driving ability is influenced by the overall state of motivation, experience and fatigue of the driver, and is dependent on higher cognitive functions, perception, response selection and sensorimotor functioning. The large number of traffic accidents attributed to so‐called ‘driver failure’ include a high percentage of accidents in which the driver had taken drugs within the last 24‐hour period before the accident occurred. Results are presented from various studies showing different effects on driving performance and reaction time following nighttime application of long‐acting and short‐acting hypnotics. Furthermore, alcohol was used as an agent interfering with the test drugs. Different benzodiazepines were tested in two different situations characterized by high and low loads of motor coordination and vigilance level. In both experimental approaches it was revealed that in comparison to other hypnotics lormetazepam belongs to the group which do not exert hangover effects on drivingrelated skills. Even if lormetazepam were taken together with alcohol in the evening no driving‐related decrements were discovered the next morning. In conclusion it could be stated that lormetazepam belongs to the class of safe hypnotics inducing driving impairment far less than that produced by 0·8 BAC mg/ml, which is the upper legal limit for driving in Germany.
Effects of regular alcohol intake and stress on mental performance, mood and cardiovascular function
Authors: Smith Andrew , Whitney Helen , Thomas Marie , Perry Kate , Brockman Pip
Published: January 2005

An experiment was conducted to examine the effects of alcohol consumption and stress on mood, mental performance and cardiovascular function. One hundred and six young adults (mean age 21.2 years) took part in the study. The results showed that alcohol consumption and stress interact to influence performance but not mood. Different effects were obtained depending on whether one examined the total number of units consumed per week or the frequency of drinking alcohol, but in both cases the effects were selective, being found only with certain stress measures and in some aspects of performance. The pattern of results was, however, consistent enough to suggest that these were not chance effects. The number of alcohol units consumed and degree of negative affect in the last week interacted reliably in analyses of the memory tasks. High scores on both were associated with improved performance (relative to low scores on both), whereas a high score on one but not the other was associated with impaired performance. Two types of effect could be distinguished in these interactions: the first, found in the working memory tasks, reflected the personality differences in the various groups; the other, seen in the episodic memory tasks, was present even when personality and gender were statistically controlled. Frequency of alcohol usage and frequency of negative life events were found to interact in the simple reaction time data, with frequent drinkers who had experienced a large number of negative life events having the slowest reaction times.
Motor effects of cholinergic stimulation of the globus pallidus in rats
Authors: Springer Paulette , Dill Russell E.
Published: January 2005

Forty‐seven rats were cannulated permanently in either the globus pallidus or neostriatum and subsequently injected with carbachol, scopolamine, or carbachol plus scopolamine. The injection of carbachol (1 μg) into the globus pallidus produced transient hyperkinetic phasic dyskinesias (84%) followed in some cases by ipsilateral circling (47%) associated with hypertonic contralateral hind limbs. This condition progressed in some rats to a cataleptic state (42%). The injection of scopolamine (50 μg) plus carbachol (1 μg) into the pallidum produced ipsilateral circling associated with hypotonia of the contralateral hind limb in a few rats. No hyperkinetic dyskinesias nor catalepsy were produced by these injections. The injection of carbachol (1 μg) in to the neostriatum produced hyperkinetic dyskinesias (86%) of long duration, minimal circling (both directions) (10%), and catalepsy (29%). These effects were blocked by the addition of 50 μg of scopolamine to the carbachol injection. Scopolamine (50–100 μg) alone produced no effects after injection into the caudate/putamen. Saline injections in the neostriatum or globus pallidus produced no motor disturbance.