bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gliogenesis in rat spinal cord: Evidence for origin of astrocytes and oligodendrocytes from radial precursors
Authors: Hirano M. , Goldman J. E. 
Published: January 2005

AbstractWe have examined glial cell lineages during rat spinal cord development by using a variety of antibodies that react with immature and mature glia. Radial glia in embryonic cord bound (1) A2B5, an antibody that reacts with a glial precursor cell population in optic nerve; (2) AbR24, which is directed against GD3 ganglioside and binds to immature neuroectodermal cells and to developing oligodendrocytes in forebrain and cerebellum; and (3) an antibody to the intermediate filament, vimentin. With time, two different populations emerged, both of which seemed to be derivatives of radial cells. One cell type expressed the astrocyte intermediate filament, GFAP, in addition to vimentin. GFAP‐containing cells eventually took on the forms of astrocytes in gray and white matter. The other type expressed carbonic anhydrase, an enzyme characteristic of oligodendrocytes and enriched in myelin. Carbonic anhydrase‐positive cells eventually developed into small cells with oligodendrocyte morphology. Our observations suggest a common lineage for astrocytes and oligodendrocytes from radial cells during spinal cord gliogenesis.
Expression of 48‐kilodalton intermediate filament‐associated protein in differentiating and in mature astrocytes in various regions of the central nervous system
Authors: Abd‐El‐Basset E. M. , Kalnins V. I. , Fedoroff S. 
Published: January 2005

AbstractIn this paper we present evidence that the 48‐kD intermediate filament‐associated protein (IFAP) is expressed relatively late in maturation of astrocytes, after they have acquired the glial fibrillary acidic protein (GFAP). In the astrocyes of white matter in the cerebellum the GFAP is detected at P3, whereas the 48‐kD IFAP is detected only at P11. In the periventricular region and the hippocampus the 48‐kD IFAP was detected at P6, long after the appearance of GFAP. In adult mice the 48‐kD IFAP was observed in GFAP‐positive astrocytes in the white matter of cerebellum, spinal cord, brainstem, and corpus callosum as well as in GFAP‐positive cells in the grey matter of cerebral cortex and spinal cord.The 48‐kD IFAP was not, however, detected in radial glia and their derivatives, in Bergmann glia or in Müller glia. Thus, not all the GFAP‐positive astroglia express the 48‐kD IFAP. Similarly, 48‐kD IFAP was not detected in cells which were GFAP‐negative.
HLA‐DRβ, ‐DQα, and ‐DQβ restriction fragment length polymorphisms in multiple sclerosis
Authors: Haegert D. G. , Michaud M. , Schwab C. , Tansey C. , Décary F. , Francis G. 
Published: January 2005

AbstractRestriction fragment length polymorphism (RFLP) studies were performed on DNA from unrelated Caucasian patients with multiple sclerosis (MS) using cDNA probes to the HLA class II genes DRβ, DQα, and DQβ. In a study of 34 patients and 34 controls who were not matched for DR type, we found that the DQβ allele‐specific RFLP or allogenotype, termed DQβlb, which corresponds at the molecular level to the DQwl serotype, is preferentially associated with MS. A significant disease association with DR2 was demonstrated by serology but this was not confirmed using DR2/Dw2‐specific RFLPs. We suggest that DQβlb is largely responsible for HLA‐associated susceptibility to MS and that the apparent MS‐DR2 serological association is due to the strong linkage disequilibrium between DR2 and DQβlb.Homozygosity of one of the two allelic bands of the DX α gene, usually termed the DXα lower (DXαL) band (which cross‐hybridizes with the DQα probe), correlated with reduced susceptibility to MS. Similarly a 5.3 kb band identified by the DQα probe in Mspl digests showed a negative correlation with MS.In an analysis of 27 DR2+ controls and 26 DR2+ patients it was found that these individuals all had DR2/Dw2‐specific RFLPs and all had identical DR2/Dw2‐associated DQβ (DQβlb) and DQα (DQαlb) allogenotypes. We detected no polymorphisms of DRβ, DQα, or DQβ genes among the DR2+ MS patients which distinguished them from normals. This suggests that the various HLA class II genes associated with MS are normal and not variant alleles.Because of strong linkage disequilibrium, a particular DRβ allogenotype in Caucasians is characteristically associated with specific DQα and DQβ allogenotypes. However, approximately 20% of all MS patients studied showed anomalous DR‐DQ associations including absence of anticipated allogenotypes or inappropriate allogenotypes. This result suggests that in at least some cases, aberrant DR‐DQ associations may be important in the pathogenesis of MS.
Chronic L‐deprenyl does not alter the restoration of striatal dopamine in MPTP‐lesioned mice
Authors: Wiener H. L. , Hashim A. , Lajtha A. , Sershen H. 
Published: January 2005

AbstractThe present study examined the effect of chronic L‐deprenyl on dopaminergic terminal function after mouse striatal terminals were lesioned with 1‐methyl‐4‐phenyl‐1, 2, 3, 6‐tetrahydropyridine (MPTP; 2 × 30 mg/kg s.c.). In the MPTP‐lesioned mice, the level of dopamine was decreased by 59% 1 week after MPTP administration and by 22% at 16 weeks. Chronic administration of L‐deprenyl (0.1 mg/kg, once weekly for up to 16 weeks) did not alter striatal dopamine metabolism, although monoamine oxidase B activity was reduced by 50% during this 16‐week period, and did not alter the rate of restoration of the level of striatal dopamine.
Herpes simplex virus type I infection of the CNS induces major histocompatibility complex antigen expression on rat microglia
Authors: Weinstein D. L. , Walker D. G. , Akiyama H. , McGeer P. L. 
Published: January 2005

AbstractRats were infected with herpes simplex virus type I (HSV‐1) by corneal scarification. The spread of virus in the brain, the infiltration of leucocytes into infected areas, and the expression of major histocompatibility complex (MHC) glycoproteins by brain cells were assessed as a function of time by immunohistochemistry. Virus moved along neuronal pathways, achieving widespread distribution in the brain by days 8–10 when the illness appeared most severe. Granulocytes, T‐lymphocytes, and monocytes infiltrated the tissue matrix at sites of infection. Microglial cells were induced to express MHC class I and class II glycoproteins. Reactive microglia near the sites of infection most vigorously expressed such glycoproteins. At the peak of the infection they were detectable on microglia throughout the brain, including areas apparently separated from unfection. Evidence of viral antigens, as well as microglial MHC expression, had largely disappeared by day 30. Neurons, astrocytes, and oligodendroglial cells failed to express MHC antigens.
Cerebellar ganglioside abnormalities in pcd mutant mice
Authors: Seyfried T. N. , Yu R. K. 
Published: January 2005

AbstractThe distribution of cerebellar gangliosides was studied in Purkinje cell degeneration (pcd/pcd) mutant mice at postnatal days 25, 30, 50, and 150. These mutants lose the majority of Purkinje cells between 18 and 50 days of age. A reactive gliosis accompanies Purkinje cell loss and a partial loss of granule cells occurs in pcd/pcd mice older than p50. Purkinje cell loss is associated with significant reductions in cerebellar weight and ganglioside concentration. This neuronal loss was also developmentally correlated with reductions of gangliosides GT1a/LD1 and GT1b and with elevations of GD3. These results agree with previous findings in other cerebellar mutants that GT1a/LD1 and GT1b are concentrated in Purkinje cells and that GD3 is enriched in reactive glial cells. A slight, but significant, reduction in GD1a concentration occurred only in older pcd/pcd mice, consistent with previous findings in weaver and staggerer mice that GD1a is enriched in mature granule cells. The findings with pcd/pcd and other neurological mutants indicate that certain gangliosides can serve as cell‐surface markers for monitoring changes in cerebellar cytoarchitecture that accompany development or disease.
Induction of heat shock (stress) genes in the mammalian brain by hyperthermia and other traumatic events: A current perspective
Authors: Brown I. R. 
Published: January 2005

AbstractIs the heat shock response physiologically relevant? For example, following hyperthermia or ischemia, what neural cell types show induction of heat shock genes and what is the time course of the effect? Initial experiments in this area demonstrated the prominent Induction of a 70 kDa heat shock protein (hsp70) when labeled brain proteins isolated from hyperthermic animals were analyzed. Recently, in situ hybridization and immunocytochemistry have been utilized to map out the pattern of expression of both constitutively expressed and stress‐inducible members of the hsp70 multigene family. Different types of neural trauma have been found to induce characteristic cellular responses in the mammalian brain with regard to the type of brain cell that responds by inducing hsp70 and the timing of the induction response. Fever‐like temperature causes a dramatic induction of hsp70 mRNA within 1 hr in fiber tracts of the fore‐brain and cerebellum, a pattern consistent with a strong glial response to heat shock. Tissue injury, namely, a small surgical cut in the cerebral cortex, induces a rapid and highly localized induction of hsp70 mRNA in cells proximal to the injury site. Using an immunocytochemical approach, a neuronal pattern of induction of hsp70 has been demonstrated following ischemia or kainic acid–induced seizures. It is apparent that the pattern of induction of hsp70 may be a useful early marker of cellular injury and may identify previously unrecognized areas of vulnerability in the nervous system.
Cobalt‐Dependent potentiation of net inward current density in Helix aspersa neurons
Authors: Kim Y‐K. , Woodruff M. L. 
Published: January 2005

AbstractA low concentration of transition metal ions Co2+ and Ni2+ increases the inward current density in neurons from the land snail Helix aspersa. The currents were measured using a single electrode voltage‐clamp/internal perfusion method under conditions in which the external Na+ was replaced by Tris+ the predominant external current carrying cation was Ca2+ and the internal perfusate contained 120 mM Cs+/0 K+; 30 mM tetraethylammonium (TEA) was addedexternally to block K+ carrent. In presence of Co2+ (3 mM) Ni2+ Ca2+ currents were stimulated normally by voltage‐dependent activation of Ca2+ channels. There was a 5‐10% decrease in the rate of rise of the inward current The principal effect of Co2+ and Ni2+ current density seems to be a decrease in the rate at which the inward currents decline during a depolarizing voltage pulse. The results may be due to a decrease in a voltage‐dependent or Ca2+‐dependent outward current and/or an inhibition of Ca2+ channel inactivation. Outward current under these conditions (zero internal K+) was significant and most likely due to Cs+ efflux through the voltage activated or Ca2+‐activated nonspecification channels. Co2+ is an extremely effective blocker of this outward current. These results are not an artifact of internal perfusion or the special ionic conditions. Intracellular recording of unperfused neurons in normal Helix Ringer solution showed that the Ca2+‐dependent action potential duration was increased significantly by low concentrations of Co2+. This result is consistant with the Co2+ ‐dependent increase in inward (depolarizing) current seen in voltage‐clamp experiments.
Quantitative image analysis with densitometry for immunohistochemistry and autoradiography of receptor binding sites—methodological considerations
Authors: Peretti‐Renucci R. , Feuerstein C. , Manier M. , Lorimier P. , Savasta M. , Thibault J. , Mons N. , Geffard M. 
Published: January 2005

AbstractMajor technical progress in the development of computer‐based image analysis has made possible the entry of autoradiography and immunohistochemistry into a new era where quantification by densitometry has become easily accessible. Autoradiography could become quantitative and displayed adequate reproducibility with the help of emulsion‐coated films and the use of scales of standards of known radioactivity exposed and analyzed in parallel to the tissue sections.Immunohistochemistry after revelation by a color‐based enzymatic technique can also become quantitative, providing that standardization of the crucial steps of the procedure and calibration through a parallel treatment ofa scale of antigen standards can be ensured. Such an approach is described here in the rat with reference to tyrosine hydroxylase (TH), the main synthesizing enzyme for catecholamines, and with dopamine (DA) itself, a catecholaminergic neurotransmitter. The different parts of the procedure, which can influence the results, such as the fixation of the animals by perfusion and the evaluation of the fluctuations via the calibration curve, are discussed in detail.Biological validation of the proposed procedure is described by reference to experiments already well documented biochemically, such as the induction effect of reserpine on TH in the rat locus coeruleus and the depleting effect of α‐methyltyrosine (AMPT), a well‐known blocker of TH activity, on rat striatal DA content. Finally the importance of restricting the measurements to the (pseudo)linear portion of the calibration curve is illustrated by the autoradiographic identification of the differential intrastriatal repartition of the dopaminergic D1 and D2 receptorsites, particularly the dual patch‐matrix compartments.
Expression of protein kinase C isozymes in primary neuronal cultures of the rat cerebellum
Authors: Shimohama Shun , Uehara‐Kunugi Y. , Terai K. , Taniguchi T. , Kimura J. , Saitoh T. 
Published: January 2005

AbstractProtein kinase C (PKC), a family of closely related enzymes, has been implicated in molecular processes involved in differentiation in a variety of cells, including neuronal cells. We studied the presence and distribution of four PKC isozymes immunocytochemi‐cally in primary neuronal cultures of the rat cerebellum. We employed four anti‐PKC antisera raised against synthetic peptides predicted from the cDNA sequence of the C‐terminal portion of four PKC isozymes, a, βI, βII, and γ‐ The majority of neurons were PKC(βII) immunoreactive both in the early and late (14 days) stage of culture, whereas PKC(α)‐, (βI)‐, and (γ)‐immunoreactive neurons were most abundant in the late stage of culture. Im‐munoreactivity of each PKC was high in the cytoplasm, processes, and growth cones. Prominent nuclear staining was observed with anti‐PKC(γ) antibody. These results are in contrast with in vivo results where each PKC isozyme is localized in a distinct population of neurons and subcellular compartment, suggesting the presence of regulatory mechanisms for PKC expression and compartmentalization in vivo.
Glutamine stimulates growth in rat cerebral endothelial cell culture
Authors: Dux E. , Noble L. , Chan P. H. 
Published: January 2005

AbstractEndothelial cells were isolated from rat cerebral cortices using combined enzymatic digestions and Percoll gradient centrifugation. Primary cultures were subsequently grown on collagen‐covered dishes in a medium containing 20% fetal calf serum and 0.6 mmol glutamine. The majority of cultures became confluent by day 7 or 8, but some could not reach confluence. The cells were fusiform in shape and exhibited immunoreactivity to factor VIII‐related antigen and binding to the lectin Griffonia simplicifolia. Exposure of cultures to media containing 2.6 mmol glutamine resulted in accelerated growth (in cultures were confluent at days 3–4) and change in culture morphology, namely the formation of circular, cell‐free areas. However, this treatment did not restore γ‐glutamyl transpeptidase activity that was lost during cultivation. As for other amino acids, asparagine was less potent, glycine and phenylalanine failed to mimic the glutamine effect. In summary, glutamine stimulates growth of cerebral endothelial cells in vitro and so it may supplement for other growth factors in the culture media.
Actin and actin‐binding proteins in differentiating astroglia in tissue culture
Authors: Abd‐El‐Basset E. M. , Ahmed I. , Fedoroff S. 
Published: January 2005

AbstractIn this paper we have described the organization of F‐actin and actin‐binding proteins (ABP): α‐actinin, myosin, tropomyosin, caldesmon, vinculin, talin, and spectrin, in differentiating astroglia in colony cultures. We observed that the microfilament (MF) network arrangements differ at various stages of astroglia development, but the composition of MF bundles and stress fibers is the same at all developmental stages. F‐actin is closely colocalized with myosin, tropomyosin, caldesmon, and α‐actinin. The striated pattern of myosin, tropomyosin, and caldesmon are superimposable. Tropomyosin and caldesmon extend along F‐actin but are interrupted for short periods, whereas myosin is interrupted for longer periods. α‐actinin colocalizes with tropomyosin and caldesmon but not with myosin. In astroglia at different stages of development spectrin is arranged in the form of fine networks spreading through the cell and does not follow the arrangement of MF bundles. Only F‐actin, α‐actinin, and vinculin can be detected at cell‐cell junctions. In the areas of the focal contacts, F‐actin, α‐actinin, vinculin, and talin are present. They overlap each other, although talin and vinculin extend toward the cell membrane beyond F‐actin and α‐actinin.Astroglia undergo well‐defined states of nonmotility, motility, and nonmotility again during differentiation. The changes in motility are paralled by changes in the organization of F‐actin and ABP: as GFAP‐containing intermediate filaments increase in differentiating astroglia, the F‐actin and ABP are down‐regulated, leading to non motility.
Association of ezrin isoforms with the neuronal cytoskeleton
Authors: Brigbauer E. , Dinsmore J. H. , Winckler B. , Lander A. D. , Solomon F. 
Published: January 2005

AbstractWe are studying the changes in the organization of the cytoskeleton which accompany expression of differentiated neuronal morphology. Of particular interest is the elaboration of growth cones, the motile domains of the neuronal plasma membrane, and the cytoskeletal structures that underlie them. A candidate for a component of the growth cone cytoskeleton of cultured hippocampal neurons is the antigen recognized by the monoclonal antibody, 13H9 (Birgbauer and Solomon, J Cell Biol 109:1609–1620, 1989; Goslin et al., J Cell Biol 109:1621–1631, 1989). That antibody binds strongly to growth cones, but barely stains neurites. The characterization of the antigen, both biochemical and microscopic, suggests that it may interact with microfilaments and microtubules. We have established that 13H9 recognizes a subset of the isoforms of ezrin (unpublished results). Here, we describe the properties and localization of ezrin isoforms in differentiating neuronal cells, using two in vitro systems and developing spinal cord. In embryonal carcinoma cells, both the abundance of ezrin and the proportion of ezrin associated with the cytoskeletal fraction increase upon induction of neuronal differentiation with retinoic acid. In the neuronal cells within such cultures, the 13H9‐positive forms of ezrin are enriched in the growth cone, while the bulk of ezrin identified by a polyclonal antibody shows no specific localization. In mouse DRG neurons, 13H9 staining is asymmetrically distributed along the edges of the complex growth cones of these cells. Staining of developing spinal cord in rat embryos also demonstrates that the 13H9‐positive forms of ezrin do not colocalize with the majority of ezrin. These results support the conclusion that ezrin is a component of the neuronal cytoskeleton, and that the localization of covalently distinct isoforms of the protein may be significant for growth cone function.
Tyrosine phosphorylation and immunodetection of vinculin in growth cone particle (GCP) fraction and in GCP‐cytoskeletal subfractions
Authors: Igarashi M. , Komiya Y. 
Published: January 2005

AbstractThe growth cone, the motile tip of developing neuronal processes, is considered responsible for the exact guidance of axons and synaptogenesis. High activity of tyrosine kinases in growth cones may contribute to the functions of growth cones. Our previous work revealed that vinculin is one of the endogenous substrates for intrinsic tyrosine kinases in the growth cone particle (GCP) fraction isolated from fetal rat brain. In the present study, we examined tyrosine phosphorylation and immunoblot analysis of vinculin in various fractions from fetal rat brains and adult synaptosomal fraction. Tyrosine phosphorylation of vinculin in the GCP fraction was more prominent than in any other fraction from fetal brain or synaptosomes from adult Compared to other fractions, however, the enrichment of vinculin in the GCP fraction was not observed. Tyrosine phosphorylation of vinculin in the fraction was inhibited by genistein, a specific tyrosine kinase inhibitor. Although vineulin was also phosphorylated by protein kinase C in the GCP fraction, it incorporated a much smaller amount of 32P than MARCKS protein or GAP‐43. The cytoskeletal subfraction from the GCP fraction contained a considerable amount of vineulin and it was one of the major substrates for tyrosine kinases in the GCP cytoskeleton. The membrane skeleton from the GCP fraction contained a low amount of vinculin but showed high kinase activity that phosphorylated vineulin. Taken together, our results suggest that tyrosine phosphorylation of vinculin contributes to the cytoskeletal organization of growth cones.
Establishment and characterization of a human leptomeningeal cell line
Authors: Murphy M. , Chen J‐N. , George Donna L. 
Published: January 2005

AbstractHuman leptomeningeal cells grown in culture were immortalized via transfection with an SV40 large T antigen gene construct under the control of the Rous sarcoma virus promoter. This cell line, designated LTAg2B, maintained the polygonal morphology characteristic of primary cultures, and stained positively in early passage for cytokeratin, a specific marker for arachnoid cells of the leptomeninges. Additional immunofluorescent staining revealed that these cells express vimentin and desmoplakin as well; these antigens have been found together only in normal arachnoid tissue and in meningiomas, which are the neoplastic derivatives of leptomeningeal cells. Significantly, LTAg2B cells demonstrate a greatly increased life span and growth rate relative to primary cultures. The establishment of this cell line should thus facilitate studies on the cellular and molecular biology of leptomeningeal cells, as well as elucidate their roles in certain pathological situations involving the leptomeninges, such as meningitis and meningioma tumor formation.
Establishment of highly enriched type‐2 astrocyte cultures and quantitative determination of intense glutamine synthetase activity in these cells
Authors: Juurlink B. H. J. , Hertz L. 
Published: January 2005

AbstractWe report procedures that allow one to develop and maintain cultures highly enriched in rat neopallial type‐2 astrocytes. Even after four weeks such cultures consist of more than 90% type‐2 astrocytes, ˜ −5% O‐2A progenitors and fewer than 2% type‐1 astrocytes. Their survival for more than 5 days requires the addition of conditioned medium from type‐1 astrocyte cultures. The type‐2 astrocytes have an intense glutamine synthetase activity whose basal level is sevenfold higher than in type‐1 astrocytes. The glutamine synthetase activities of both the type‐2 and type‐1 astrocytes are increased after exposure to cortisol. Thus, type‐2 astrocytes express the two quint‐essential astrocytic features: glial fibrillary acidic protein (previously reported by others) and glu‐tamine synthetase.