bluuebunny/crossref_metadata_2025_split huggingface dataset:
Survival and proliferation in developing neuroblasts in cultures derived from embryos treated with ethanol during early neuroembryogenesis: Effects attenuated by somatostatin
Authors: Kentroti S. , Vernadakis A. 
Published: January 2005

AbstractEthamol exerts profound effects both in ovo and in culture on neuronal phenotypic expression. In order to define more directly the neuronal growth parameters sensitive to the neurotoxic effects of ethanol, embryos were exposed to ethanol (10 mg/50 μl/day) or saline (control) at embryonic days 1 and 2; neuron‐enriched cultures prepared from these treated embryos at 3 days of embryonic age. Cultures from both groups were labeled with [3H] thymidine and assessed for effects on neuronal survival and proliferation in culture. Treatment of embryos with ethanol in ovo resulted in a marked enhancement in normal neuronal death in culture with no significant effect on proliferation. Whereas somatostatin (SRIF) had no effect on normally occurring neuronal death in control cultures, addition of SRIF (100 nM) to the culture medium attenuated the ethanol‐induced neuronal cell death. Videometric analysis revealed that pretreatment of embryos with ethanol resulted in formation of more and larger aggregates as compared with controls, an effect that was augmented by addition of SRIF to the medium. The most profound effect of ethanol on growth patterns was observed in neurite outgrowth showing a marked reduction in both neurite number and length in embryos pretreated with ethanol. SRIF enhanced neurite outgrowth (neurite number and length) in cultures derived from ethanol‐treated embryos. These results suggest that the ethanol‐induced deficits in neuronal survival and morphology are reversible. We conclude that SRIF may enhance neuronal survival by promoting neuritic outgrowth, thus establishing the essential target cell contacts necessary for cell survival.
Schwann cell nerve growth factor receptor expression during initiation of remyelination
Authors: Fan X. , Gelman B. B. 
Published: January 2005

AbstractInitiation of remyelination is a promising therapeutic strategy to treat patients with demyelinating diseases, but specific factors that control remyelination are not clear. We first reported that expression of nerve growth factor receptor (NGFR) was increased during initiation of remyelination (Fan and Gelman,Journal of Neuropathology and Experimental Neurology49:312, 1990). In this study, we characterized the timing and cellular localization of NGFR expression in a model of segmental demyelination and remyelination using immunohistochemistry and monoclonal antibody 192‐IgG, and compared it to an axonal neuropathy. At the onset of demyelination induced by tellurium (Te) poisoning, NGFR antigenicity was selectively expressed within and around demyelinating internodes in rat sciatic nerve. Dual fluorescence staining with myelin‐specific antigen showed that NGFR colocalized with demyelinated internodal units with relative specificity; Schwann cell S‐100 protein showed a concomitant down‐regulation in injured internodes. Peak expression of NGFR occurred during the transition between demyelination and remyelination (day 8 of Te), then declined exponentially. NGFR expression was most prominent in the cytoplasm of daughter Schwann cells as they established contact with denuded axons, and was sharply repressed as compact myelin began to accumulate. Rare colocalization with neurofilament antigens revealed intraaxonal deposits of NGFR in segmental demyelination. In the nerve crush model, Schwann cell NGFR expression was not segmentally distributed and was up‐regulated for a longer period of time. Our data establish that NGFR expression in the peripheral nervous system is not strictly linked to axon elongation, and that it probably functions during the initiation of myelination.
The structural integrity of glial scar tissue associated with a chronic spinal cord lesion can be altered by transplanted fetal spinal cord tissue
Authors: Houle J. 
Published: January 2005

AbstractThe potential for fetal spinal cord (FSC) tissue transplants to modify an established glial scar or to restrict the reformation of a scar following surgical manipulation of a chronic lesion site was studied in the injured rat spinal cord. Six to eight weeks after preparation of a hemisection lesion cavity, glial scar tissue was left intact in one group, whereas in a second group it was excised prior to transplantation of a suspension of FSC tissue. From the first group, examination of serial sections through the graft‐host interface that had been immunoreacted for glial fibrillary acidic protein (GFAP) demonstrated that in many cases the glial scar no longer was a continuous wall separating the two tissues. Quantitation of the area occupied by these discrete gaps in the scar provided an Index of Fusion, indicating the extent of direct contact between the transplant and host spinal cord. In some animals this constituted as much as 60% of the interface, while in others there were no breaks in the scar (0% fusion). Reinjury of the spinal cord lead to a rapid astrocytic response culminating in the re‐establishment of a dense matrix of glial cells and processes covered by a basal lamina. This reformed scar effectively isolated the spinal cord from the external environment of the cavity. When FSC tissue was transplanted after first removing scar tissue the continuity of reformed glial scarring at the graft‐host interface was altered. Distinct gaps in the scar appeared randomly along the interface. The mean Index of Fusion for animals receiving a moderate reinjury (removal of scar tissue only) was not as high as for those animals in which a more severe reinjury (expansion of the cavity by 0.5 mm) was performed before transplantation. The extent of graft‐host fusion was not significantly improved when scar tissue was removed prior to transplantation. These findings support the hypothesis that the presence of FSC tissue will have an effect on the persistence of glial scar tissue in a chronic lesion site as well as limit the extent to which a new scar is formed in response to a second injury to the spinal cord.
Substance P immunoreactivity of rat brain stem neurons in primary culture
Authors: Jacquin T. D. , Denizot J. P. , Denavit‐Saubie M. 
Published: January 2005

AbstractSubstance P (SP)‐ergic neurons from 16/17 day‐embryonic rat brain stem in primary culture were identified by immunocytochemistry using biotinylated avidine and phosphatase alcaline methods with affinity‐purified anti‐SP antibodies. An average of 84% of neurons contained SP from day 9 to day 21 after plating. These in vitro data show that SP‐containing neurons develop in our culture conditions. SP may act as a maturation factor as well as a neurotransmitter.
Loss and recovery of activities of α+ and α isozymes of (Na+ + K+)‐ATPase in cortical focal ischemia: GM1 ganglioside protects plasma membrane structure and function
Authors: Mahadik S. P. , Bharucha V. A. , Stadlin A. , Ortiz A. , Karpiak S. E. 
Published: January 2005

AbstractAlterations in cellular membrane structure and the subsequent failure of its function after CNS ischemia were monitored by analyzing changes in the plasma membrane marker enzyme (Na+ + K+‐ATPase. The levels of two isozymes of Na+ + K+)‐ATPase, α+ and α, which have distinct cellular and anatomical distributions, were studied to determine if differential cellular damage occurs in primary and peri‐ischemic injury areas. The efficacy of monosialoganglioside (GM1) treatment was assessed, since this glycosphingolipid has been shown to reduce ischemic injury by protecting cell membrane structure/function. Using a rat model of cortical focal ischemia, levels of both ATPase isozyme activities were assayed in total membrane fractions from primary ischemic tissue (parietal cortex) and three peri‐ischemic tissue areas (frontal, occipital, and temporal cortex) at 1, 3, 5, 7, and 14 days after ischemia. No significant loss of either isozyme's activity occurred in any tissue area at 1 day after ischemia. At 5 dyas, in the primary ischemic area, both isozyme activity levels decreased by 70–75%. The α+ enzyme activity loss persisted up to 14 days, while a 17% recovery in α activity occurred. In the three peri‐ischemic tissue areas, enzyme activity losses ranged from 42%–59% at 3 days after ischemia. A complete restoration of both isozyme activities was seen at 14 days. After three days of GM1 ganglioside treatment there was no loss of total (Na+ + K+)‐ATPase activity in the three peri‐ischemic areas, and a significantly reduced loss in the primary infarct tissue. An autoradiographic analysis of brain coronal sections using 3H‐ouabain supports the enzymatic data and GM1 effects. Reductions in 3H‐ouabain binding in all cortical layers at 3 days after ischemia were visualized. GM1 treatment significantly reduced these 3H‐ouabain binding losses. In summary, time‐dependent quantitative changes in activity levels of ATPase isozymes (α+ and α) reflect the different degree of membrane damage that occurs in primary vs. peri‐ischemic tissues (e.g., irreversible vs. reversible membrane damage), and that ischemia affects cell membranes of all neural elements in a largely similar fashion. GM1 ganglioside was found to reduce plasma membrane damage in all CNS cell types. © 1992 Wiley‐Liss, Inc.
Secretion of apolipoprotein E by an astrocytoma cell line
Authors: Krul Elaine S. , Tang J. 
Published: January 2005

AbstractApolipoprotein (apo) E is a predominant protein in developing mammalian brain and in damaged peripheral nerve. Of particular interest is the observation that astrocytes in the central nervous system cease to produce apoE after nerve damage, whereas an increase in apoE production results after peripheral nerve injury. Differences in the response to injury with regard to the production of apoE may be related to dissimilarities in the abilities of the central and peripheral nervous systems to regenerate. As there are few data concerning the regulation of apoE gene expression in extrahepatic tissues, we employed a human astrocytoma cell line (CCF‐STTG1) as a model to study apoE production in astrocytes. CCF‐STTG1 cells secreted apoE constitutively in serumfree media. Cholesterol added to the media as cholesterol:phospholipid liposomes (2–100 μg/ml) or as human plasma LDL increased the amount of apoE secreted into the media, but had little or no effect on the relative abundance of apoE mRNA. By contrast, the commercially available triglyceride‐phospholipid emulsion Intralipid© added at dilutions of 1:50 to 1:500 caused a total inhibition of apoE secretion by the cells, but again, little change was noted in the relative abundance of apoE mRNA. Insulin (5 μg/ml) caused a 45–55% reduction in the amount of apoE secreted by the astrocytoma cells. Glucagon (5 μg/ml), on the other hand, did not increase apoE secretion, and apoE mRNA concentrations were not affected by either hormone treatment. ApoE was secreted from the astrocytoma cells associated with particles of plasma VLDL to IDL and HDL size. After feeding the cells with 20 μg/ml cholesterol as cholesterol:phospholipid liposomes, an increased proportion of apoE was secreted associated with the larger VLDL to IDL size particles, with a concomitant decrease in the proportion associated with the smaller HDL‐size particles. When cells were incubated with 5 μg/ml insulin, most of the apoE was associated with the HDL‐size particles. When cholesterol:phospholipid liposomes were added in the presence of insulin virtually all of the secreted apoE was found associated with the VLDL to IDL size particles. In summary, the regulation of apoE production in CCF‐STTG1 cells in many respects resembles that of other cells, including hepatocytes. However, it is clear that there remain to be identified cell specific factors which regulate apoE production in astrocytes. The CCF‐STTG1 cell line promises to provide a suitable model to investigate these questions. © 1992 Wiley‐Liss, Inc.
Laminin and its neurite outgrowth‐promoting domain in the brain in Alzheimer's disease and Down's syndrome patients
Authors: Murtomäki S. , Risteli J. , Risteli L. , Koivisto U.‐M. , Johansson S. , Liesi Päivi 
Published: January 2005

AbstractImmunocytochemistry, radioimmunoassay, immunoblotting, Northern analysis, and polymerase chain reaction (PCR) technique were applied to investigate the distribution of laminin and its neurite outgrowth domain in brains of neuropathologically verified cases of Alzheimer's disease and Down's syndrome. New antibodies against a neurite outgrowth domain of laminin were characterized and were used in localization of this peptide antigen in the human brain. Laminin was found as large punctate deposits in all plaques in the affected brains. Laminin synthesis was increased as assessed by RNA blotting and immunoblotting, and glial cells were heavily immunoreactive with antibodies for a neurite outgrowth‐promoting peptide antigen of the B2 chain of laminin. This peptide antigen not only was produced by glial cells but also was deposited in the brain tissue. As this peptide antigen promotes neurite outgrowth at low concentrations, and is specifically neurotoxic at high concentrations, it may play a synergistic role with other molecules in inducing the sprouting and neurodegeneration occurring in brains of patients with either Alzheimer's disease or Down's syndrome. © 1992 Wiley‐Liss, Inc.
Voltage‐dependent potassium currents in cultured trout oligodendrocytes
Authors: Glassmeier G. , Jeserich G. , Krüppel T. 
Published: January 2005

AbstractIonic currents were recorded in cultured oligodendrocytes from the brain of trout using the whole‐cell configuration of the patch‐clamp technique. Outward currents were evoked at membrane potentials more positive than −40 mV, which could be separated into two components according to their kinetic parameters and their sensitivity to the holding potential: a fast inactivating current which was completely suppressed by 4‐aminopyridine and reduced by tetraethylammonium and a slow steady‐state conductance which was similarly sensitive to both potassium channel blockers. The current reversal potential was close to the potassium equilibrium potential. In contrast to mammalian oligodendrocytes but in similarity with cultured Schwann cells, trout oligodendrocytes did not exhibit any inwardly rectifying currents at hyperpolarized membrane potentials. © 1992 Wiley‐Liss, Inc.
EAE cerebrospinal fluid augments in vitro phagocytosis and metabolism of CNS myelin by macrophages
Authors: Sommer M. A. , Forno L. S. , Smith Marion E. 
Published: January 2005

AbstractPrevious studies from this laboratory have shown that CNS myelin is phagocytized and metabolized by cultured rat macrophages to a much larger extent when myelin is pretreated with serum containing antibodies to myelin constituents than when it is left untreated or pretreated with non‐specific serum. In this study the effect of cerebrospinal fluid (CSF) from rabbits with experimental allergic encephalomyelitis (EAE) in promoting myelin phagocytosis was examined. Fourteen rabbits were immunized with purified myelin in Freund's complete adjuvant, seven of which developed clinical EAE symptoms. Serum and CSF were collected from EAE and control rabbits, and the CSF was centrifuged to remove cells. Sera and CSF from these rabbits and from Freund's adjuvant‐immunized controls and untreated controls were measured for IgG content by radial diffusion assay, their myelin antibody characteristics were analyzed by immunoblots, and the ability of these serum and CSF samples to promote myelin phagocytosis when used for myelin opsonization was examined. The ability of a CSF sample to enhance radioactive myelin uptake and phagocytosis by cultured macrophages as measured by the appearance of radioactive cholesterol ester was linearly proportional to its total IgG titer, and correlated approximately both with clinical symptoms of the animal and the presence of antibody against the myelin constituents myelin basic protein, proteolipid protein, and galactocerebroside. The cholesterol esterification activities of EAE sera correlated to a lesser extent with IgG levels and clinical symptoms. These results suggest a possible role for CSF‐localized anti‐myelin antibody in demyelination in the CNS by macrophages in EAE, and they encourage further study of the role of CSF antibody in cell‐mediated demyelination in multiple sclerosis. © 1992 Wiley‐Liss, Inc.
Activity and distribution of phosphoinositidase C in rat sciatic nerve
Authors: Mathew J. , Date S. , Eichberg J. 
Published: January 2005

AbstractThe hydrolysis of phosphatidylinositol‐4,5‐bisphosphate (PIP2) by rat sciatic nerve cytosolic phosphoinositidase C [phosphoinositide‐specific phospholipase C (PIC)] was studied at neutral pH and at ionic concentrations that approximate intracellular conditions. The principal water‐soluble product formed was shown to be inositol trisphosphate by anion exchange chromatography. The maximum hydrolysis rate (2.5 nmol/min/mg protein) was achieved at < 100 nM Ca2+. Hydrolysis was markedly increased to 15 nmol/min/mg protein by inclusion of K+ in the reaction mixture. In the presence of 200 mM K+, the optimum Ca2+ was increased to approximately 600 nM. Higher Ca2+ concentrations progressively inhibited PIP2 hydrolysis. Mg2+ also inhibited the reaction, but the presence of equimolar amounts of ATP and Mg2+ had no effect. Appreciable degradation of phosphatidylinositol‐4‐phosphate (PIP) also occurred in the nanomolar Ca2+ range, whereas breakdown of phosphatidylinositol (PI) required millimolar Ca2+. The presence of PIP but not PI inhibited PIP2 hydrolysis. Upon subcellular fractionation of nerve, more than 50% of recovered PIC activity was in the cytosol and about 20% was located in a myelin‐enriched fraction. Using PIP2 as substrate, PIC activities in nerves from normal and streptozotocin‐induced diabetic animals were not different. However, the myelin‐associated enzyme from diabetic animals was more labile to freezing and thawing. © 1992 Wiley‐Liss, Inc.
Regional distribution and biochemical characteristics of high molecular weight tau in the nervous system
Authors: Taleghany N. , Oblinger M. M. 
Published: January 2005

AbstractThe present study examined the distribution of the high molecular weight (HMW) tau protein isoform in the nervous system by immunoblotting and immunohistochemistry. Some of the biochemical properties of this 110 kDa tau protein were explored, including its heat stability, phosphorylation and partitioning with cold/Ca2+ stable vs. soluble microtubules. Qualitative western blot analysis revealed that HMW tau is preferentially expressed in neurons with peripherally projecting axons. For example, this isotype was present in sciatic nerve, ventral and dorsal roots, trigeminal nerve, vagus nerve, dorsal root ganglia (DRG) and spinal cord, but was present in only trace amounts in CNS regions. Another tau isoform of slightly smaller size (90–100 kDa), termed mid‐molecular weight (MMW) tau, was present in abundant quantity in optic nerve samples and detectable in several other CNS regions, including hippocampus and cerebellum. The 110 kDa HMW tau as well as MMW tau and the other tau isoforms were found to be heat stable proteins. The HMW and MMW tau isoforms preferentially partitioned with the cold and Ca+2 insoluble tubulin fraction, but the association of HMW tau with stable microtubules was very susceptible to proteolysis. Dephosphorylation of fresh tissue with alkaline phosphatase produced no apparent shift in the mobility of HMW tau on SDS‐PAGE but did alter the mobility of other brain tau isoforms, including MMW tau. Immunocytochemical staining with tau‐1 antibody in the DRG, which contains HMW tau but no other tau isotypes, showed localization to mainly small neurons and was not altered by dephosphorylation of the histological sections. This suggests that HMW tau, which contains the tau‐1 epitope, is not phosphorylated in that site. © Wiley‐Liss, Inc.
Human serum stimulates alzheimer markers in cultured hippocampal neurons
Authors: Brewer G. J. , Ashford J. W. 
Published: January 2005

AbstractThe mechanism for promoting the distinct types of lesions in the Alzheimer disease (AD) brain and other changes outside the brain is unknown. We examined neurons in culture, unprotected by glia or a blood‐brain barrier, to determine if exposure to serum from Alzheimer patients would affect markers for Alzheimer brain lesions. Rat hippocampal neurons were first grown for 4 days in a new serum‐free culture medium, then exposed for 24 hr to human sera. Sera from 12 AD patients or their spouses increased four molecular markers characteristic of Alzheimer senile plaques and neurofibrillary tangles: Alz‐50, β‐amyloid (β/A4), MAP2, and ubiquitin, each with their expected cytologic distributions. Sera from ten young adults produced significantly less stimulation. By quantitative immunofluorescence, neuronal exposure to the elderly human sera produced 1.8‐ to 2.5‐fold increases in mean fluorescent area/cell for each of these four markers relative to no serum exposure. As controls, an unrelated neuronal marker, enolase, was unaffected and fetal bovine serum did not stimulate immunoreactivity. Neuron viability and somal area were unaffected at 24 hours. The MAP2 increases were dose dependent with negligible effect at 2% serum and maximum effect at 10% serum after 24 hr. The MAP2 increase was greater after 48 hr of exposure than 24 hr and negligible at 2 hr. This stimulation of AD markers by human serum suggests that the genesis of both neuronal plaques and tangles may arise from access of toxic serum factors to susceptible neurons and/or failure to detoxify these factors. © Wiley‐Liss, Inc.
Leukemia inhibitory factor promotes the neuronal development of spinal cord precursors from the neural tube
Authors: Richards L. J. , Kilpatrick T. J. , Bartlett P. F. , Murphy M. 
Published: January 2005

AbstractRecent evidence from our laboratory has shown that leukemia inhibitory factor (LIF) can act early in peripheral nervous system development. We have investigated a potential role of LIF in the developing spinal cord. In explants and dissociated cultures of spinal cord primordium, LIF stimulated a profuse neurite outgrowth. To determine if these effects were related to neuronal differentiation, cells were plated at low cell density and stained for neurofilament. LIF stimulated an increase in the number of newly differentiated neurons, without inducing proliferation of the precursors. Given that LIF has previously reported effects as a cholinergic switching factor for sympathetic neurons, we investigated whether LIF had similar effects in these spinal cord cultures. LIF increased the number of cholinergic neurons in proportion to its overall effect on the stimulation of all neurofilament positive neurons in the culture. These data show that LIF stimulates the generation of spinal cord neurons from their precursors and further implicates a role for LIF in nervous system development. © 1992 Wiley‐Liss, Inc.