bluuebunny/crossref_metadata_2025_split huggingface dataset:
Arachidonec acid metabolism in grebil cerebra: Effects of ischemia
Authors: Hamm T. F. R. , Dorman R. V. 
Published: January 2005

AbstractPentobarbital pretreatmint may be used to predict biochemical events involved in ischemic brain damage following bilateral carotid artery ligations in the gerbil, since it reduces the subsequent edema and mortality. The effects of this anesthetec on the ischemia‐induced modifications of cerebral arachidonic acid metabolism were investigated, in order to correlate observed alterations with tissue damage. Cerebral lipids were radiolabeled in vivo with [3H] arachidonec acid prior to 10 min of cerbral ischemia and 0‐120 min of perfusion. Ischemia stimulated a 97.3% increase in unesterified [3H] arachidonate, which was dut to the loss of label from choline, inositol, and ethanolamine glycerophospholipids. Tissue reperfusion stimulated further reductions in [3H] choline and [3H] inositol glycerophospholipids, while ethanolamine glycerophospholipip and trigyceride labeling increased. Inositol glycerophospholipid, but not chline glycerophospholipid, labeling returned to control level by 60 min of reperfusion. Pentobarbital pretreatment reduced the accumulation of [3H] arachidonate by 56.2% during ischemia. It increassed the recovery of [3H]ethanolamine glycerophospholipids during the ischemic period and [3H]choling glycerophospholipids dduring the first 5 min of reperfusion. Thessses effects accountedd for the feduction of unesterifiedd [3H]arachidonate obsserved during ischemia and reperfusion.
West nile virions aligned along myelin lamellae in organotypic spinal cord cultures
Authors: Shahar A. , Lustig S. , Akov Y. , David Y. , Schneider P. , Friedmann A. , Levin R. 
Published: January 2005

AbstractOrgantypic spinal cord cultures infected with West Nile Virus (WNV) exhibited a remarkable arrangement of virions among lamellae of the myelin sheath. Virions were first observed in neurons and only at day 4 after infection appeared within the myelin lamellae. Virions were observed only in the central myelin, aligned along the interperiod lines and therefor attached to the outer side of the oligodendrocyte membrane. In spite of this peculiar location of the virions, their presence was not associated with severe damage to the axon or to the myelin sheath. The causes of the formation of this viral pattern, its morphological features, and the role which it might have in viral infection in vivo are considered.
Regulation of thyroid hormone receptor and c‐erbA mRNA levels by butyrate in neuroblastoma (N2A) and glioma (C6) cells
Authors: Yusta B. , Ortiz‐Caro J. , Bedo G. , Pascual A. , Aranda Ana 
Published: January 2005

AbstractButyrate produced a biphasic modulation of the thyroid hormone receptor in neuroblastoma N2A cells increasing receptor number by 20–35% at concentrations 0.25–0.75 mM and decreasing receptor levels by 30–55% at 2–4 mM. The half‐life of the receptor, as assessed by its disappearance after incubation with 18 μM cycloheximide was 8.4 hr in control cells and 10.3 hr and 5.0 hr in cells incubated with 0.25 and 4 mM butyrate, respectively. This compound increased the abundance of multyacetylated forms of histone H4 from 30% in control cells to almost 70% with butyrate 4 mM. In glioma C6 cells, the fatty acid produced a dose‐dependent increase of receptor levels (up to 3–4‐fold with 2–5 mM butyrate) and had little effect in increasing multiacetylation (from 30% in controls to 42–46% with 2–5 mM butyrate). Recent studies have shown that the c‐erbA proto‐oncogen codes for the thyroid hormone receptor. In N2A and C6 cells, 2 c‐erbA‐related mRNAs, one measuring 2.6 kb and the other 6 kb, were detected. Both forms were differently regulated by butyrate. This compound decreased the abundance of the 2.6 kb forms in both cell types, even at the concentrations at which there was an elevation of receptor levels. Only the largest mRNA correlated with receptor concentration increasing by 2–3‐fold after treatment of C6 cells with butyrate, and undergoing a smaller but biphasic change in N2A cells.Our data suggest that modification of chromatin structure probably secondary to acetylation induces changes in thyroid hormone receptor levels in neuroblastoma and glioma cells by affecting both receptor stability and receptor mRNA levels.
Excitatory amino acid neurotoxicity in cultured retinal neurons: Involvement of N‐methyl‐D‐Aspartate (NMDA) and Non‐NMDA receptors and effect of ganglioside GM1
Authors: Facci L. , Leon A. , Skaper S. D. 
Published: January 2005

AbstractCultures of chicken day 8 embryo retinal cells, essentially free of contaminating non‐neuronal elements, were used to examine the neurotoxicity of various excitatory amino acid transmitter receptor agonists. At 7 days in vitro, N‐methyl‐D‐aspartate (NMDA), following 24 hr exposure to 0.1‐1.0 mM, destroyed 60‐70% of the multipolar neurons, but apparently spared photoreceptors. The cytotoxic effect of NMDA was prevented by extracellular Mg2+ or phencyclidine, suggesting a role for the NMDA ion channel; competitive NMDA antagonists were also neuroprotective. The mixed excitatory amino acid receptor agonist glutamate (0.1‐1.0 mM) was also neurotoxic (∼70% loss of multipolar neurons) and strongly blocked by NMDA (but weakly by non‐NMDA) antagonists and Mg2+, indicating a major action at NMDA receptors. As with NMDA, glutamate did not appear to affect photoreceptors. The neurotoxic action of kainate against multipolar retinal neurons, as reported by others, was confirmed here. Kainate neuronal injury was sensitive to the quinoxalinedione non‐NMDA antagonists 6,7‐dinitroquinoxaline‐2,3‐dione (DNQX) and 6‐cyanoquinoxaline‐2,3‐dione (CNQX), but not to Mg2+ or phencyclidine. Ibotenate and quisqualate, even at millimolar concentrations, were not neurotoxic. The monosialoganglioside GM1 was also effective in reducing NMDA and non‐NMDA agonist neurotoxicity to retinal neurons. Maximal ganglioside benefit required 1‐2 hr of pre‐treatment with 100‐200 μM GM1.The percentage of multipolar neurons remaining after the neurotoxin insult approximately doubled with GM1 treatment. Gangliosides may thus have a therapeutic potential in excitatory amino acid‐initiated neuropathologies.
Phosphoinositide breakdown in isolated myelin is stimulated by GTP analogues and calcium
Authors: Golly F. , Larocca J. N. , Ledeen R. W. 
Published: January 2005

AbstractPurified myelin from rat brainstem, prelabeled in vivo by intracerebral injection of [3H]myoinositol, showed enhanced breakdown of phosphoinositides on treatment with 5'‐guanylylimidodiphosphate [Gpp‐(NH)p] and Ca2+. Concentration variation of the former in the presence of Ca2+ snowed a dose‐dependent release of inositol 1,4‐bisphosphate (IP2) and inositol 1,4,5‐trisphosphate (IP3), while inositol 1‐phosphate (IP) release was erratic. Concentration‐dependent release of IP2 and IP3 was also observed with Ca2+ as the variable in the presence of Gpp(NH)p. Carbachol, when present, did not enhance the stimulatory effect of Gpp(NH)p alone. Addition of diphosphoglycerate during incubation enhanced IP3 at the expense of IP2, suggesting the presence of IP3 phosphatase in mylein.
Type II glucocorticoid receptors are expressed in oligodendrocytes and astrocytes
Authors: Vielkind U. , Walencewicz A. , Levine J. M. , Bohn Martha Churchill 
Published: January 2005

AbstractGlucocorticoid hormones affect gene expression directly at the level of transcription via intracellular receptors that translocate to the nucleus in the presence of steroid. In the brain, two types of high‐affinity receptors bind glucocorticoids, the type I, mineralocorticoid receptor and the type II, glucocorticoid receptor (GR). Both receptor types are expressed by many types of neurons. Although binding studies have suggested that glial cells may also express receptors, the expression of these receptors in specific classes of glia has not been studied previously. This immunocytochemical study was undertaken to determine which of the different classes of glial cells express type II GR. Primary cultures of mixed glial cells from rat cerebrum and cerebellum, purified oligodendrocytes and astrocytes. as well as two glial tumor cell lines were screened for the expression of glucocorticoid receptors using a mouse monoclonal antibody directed against rat liver GR (BuGR‐2). Glial cell types were identified by morphology and immunoreactivity (IR) with antibodies directed against glial fibrillary acidic protein (GFAP), cyclic nucleotide phosphodiesterase (CNP), or myelin basic protein (MBP). Double immunofluorescence microscopy revealed that all GFAP‐IR cells (type 1 and type 2 astrocytes), all CNP‐ or MBP‐IR cells (oligodendrocytes), as well as immature and intermediate cell types expressed GR, although at different levels. C6 glioma and JScl1 Schwannoma cells were observed to express moderate to high levels of GR. Furthermore, cells grown in the absence of glucocorticoids had diffuse GR staining over the cytoplasm, whereas cells grown in the presence of the synthetic glucocorticoid dexamethasone had strong nuclear staining. These results demonstrate that, in vitro, all classes of glial cells express glucocorticoid receptors that can translocate to the nucleus in the presence of hormone. These observations suggest that glial cells are major targets for glucocorticoid‐directed control of gene transcription in the nervous system.
Laminin‐mediated process formation in neuronal cells involves protein dephosphorylation
Authors: Weeks B. S. , DiSalvo J. , Kleinman H. K. 
Published: January 2005

AbstractLaminin mediates neural adhesion and process formation. A possible signal transduction pathway for laminin was investigated in both NG108‐15 and PC12 neuronal cells using radiolabeling studies as well as various stimulators and inhibitors of phosphatases and kinases. Using [32p]‐ortho‐phosphate, laminin caused a decrease in the TCA‐precipitable counts. Further, laminin stimulated dephosphorylation of laminin binding proteins of 110 kDa, 67 kDa, and 45 kDa and this dephosphorylation was blocked by the phosphatase inhibitor, okadaic acid, and the protein kinase C stimulator, TPA. The phosphatase inhibitors okadaic acid and vanadate, as well as the protein kinase C stimulators, TPA and DAG, blocked laminin‐mediated process formation. Inhibitors of kinase activity such as H‐7, H‐8, and H‐9 increased laminin‐mediated neural process formation. Since phosphate incorporation into laminin‐binding proteins is decreased by laminin and because both phosphatase inhibitors and kinase stimulators inhibit laminin‐mediated process formation, we conclude that dephosphorylation events promote the neural cell response to laminin.
Aspartate‐70 to glycine substitution confers resistance to naturally occurring and synthetic anionic‐site ligands on inovo produced human butyrylcholinesterase
Authors: Neville L. F. , Gnatt A. , Loewenstein Y. , Soreq H. 
Published: January 2005

AbstractThe “atypical” allelic variant of human butyrylcholinesterase (BuChE) can be characterized by its failure to bind the local anesthetic dibucaine, the muscle relaxant succinylcholine, and the naturally occurring steroidal alkaloid solanidine, all assumed to bind to the charged anionic site component within the normal BuChE enzyme. A single nuclcotide substitution conferring a change of aspartate‐70 into glycine was recently reported in the CHE gene encoding BuChE from several individuals having the “atypical” BuChE phenotype, whereas in two other DNA samples, this mutation appeared together with a second alteration conferring a change of serine‐425 into proline. To separately assess the contribution of each of these mutations toward anionic site interactions in BuChE, three transcription constructs were engineered with each of these substitutions alone or both of them together. Xenopus oocyte microinjection of normal or mutated synthetic BuChEmRNA transcripts was employed in conjunction with biochemical analyzes of theresultant recombinant BuChE variants. The presence of the Gly‐70 mutation alone was found to render the enzyme resistant to 100 μM solanidine and 5 mM succinylcholine; concentrations sufficient to inhibit the “normal”, Asp‐70 containing BuChE by over 50%. Furthermore, when completely inhibited by the organophosphorous poison diisopropylfluorophosphate (DFP), Gly‐70 BuChE failed to be reactivated by 10 mM of the cholinesterase‐specific oxime pyridine 2‐aldoxime methiodide (2‐PAM); a concentration restoring about 50% of activity in the “normal” Asp‐70 recombinant enzyme. The Pro‐425 mutation alone had no apparent influence on BuChE interactions with any of these ligands. However, it conferred synergistic effects on some of the anionic site changes induced by the Gly‐70 mutation. Thus, in addition to being resistant to soianidine and to 2‐PAM reactivation, the Gly‐70/Pro‐25 variant completely failed to bind either dibucaine (1 mM) or succinylcholine (1,000 mM), 20‐fold higher concentrations than those inhibiting the single Gly‐70 mutant. In view of the evolutionary conserved Asp‐70 and Ser‐425 peptide domains in all known cholinesterases, these findings suggest that the Asp‐70 residue serves as part of the anionic site responsible for binding charged substrates throughout the family of cholinesterases and that genetically linked mutations in these two peptide domains may confer selection advantage through their synergistic effects on BuChE resistance to inhibitors.
Somatic cell genetic analysis of the galactocerebrosidase gene: Lack of complementation in human Krabbe disease/twitcher mouse cell hybrids
Authors: Skiba M. C. , Lyerla T. A. , Konola J. T. , Raghavan S. 
Published: January 2005

AbstractThe inherited deficiency of galactosylceramide β‐galactosidase (E.C. 3.2.1.46: galactocerebrosidase) activity results in globoid cell leukodystrophy in humans (Krabbe disease) and in mice (twitcher mutant). To determine whether Krabbe patients, cells complement twitcher cells to produce, in hybrid combination, greater than deficient levels of galacto‐cerebrosidase activity, five separate crosses were made between an established twitcher mouse cell line and five cell strains from unrelated Krabbe disease patients. A total of 57 twitcher mouse/Krabbe somatic cell hybrid lines developed from all of these crosses were deficient in galactocerebrosidase activity despite the presence of human chromosomes 14 or 17, which have been previously implicated as bearing the galactocerebrosidase gene. A control cross between twitcher mouse/positive control human fibroblasts resulted in 14 of 21 independent hybrid lines that expressed higher than deficient levels of galactocere brosidase activity. The lack of complementation between Krabbe disease patient and twitcher mutant mouse cells provides further evidence that the twitcher mouse is an authentic murine model for Krabbe disease and supports the hypothesis that the mutations in both species are within the structural gene for the galactocerebrosidase enzyme.
Expression of a chimeric VIP gene is targeted to the intestine in transgenic mice
Authors: Agoston D. V. , Bravo D. T. , Waschek J. A. 
Published: January 2005

AbstractWe showed previously that a gene construction that consisted of 5.2 kb of 5' flanking sequence, the first exon, and part of the first intron of the human gene encoding vasoactive intestinal peptide (VIP) fused to the reporter gene chloramphenicol acetyltransferase (CAT) fully mimicked the diverse behavior of the endogenous VIP gene when transfected into subclones of the human neuroblastoma cell line SK‐N‐SH (Waschek et al., 1988). To determine if the same sequences were sufficient to target expression of a reporter to VIP‐producing tissues in the mouse, we initiated a pilot study in which we generated four transgenic mice or mouse lines that contained the VIPCAT fusion gene. Detectable levels of CAT were found in the ileum of either founder or offspring of each of the transgenic mouse lines. In all other tissues tested, CAT activity was either below the level of detection or the transgene was not expressed, with the exception of one mouse in which ectopic expression in the cerebellum was observed. The results indicate that the VIP sequences utilized were sufficient to direct expression of the transgene to the intestine, but not necessarily to other sites of VIP expression.To investigate what specific DNA sequences might confer VIP expression in the intestine and other sites, we analyzed further the VIP gene in SK‐N‐SH subclones using VIP/luciferase fusion gene constructions. A 0.6 kb DNA fragment located between 4.0 kb and 4.6 kb upstream from the VIP transcriptional start site was found to impart a high level of expression in one subclone and an increased degree of phorbol ester induction in another. These and other data indicate that multiple transcriptional elements control VIP expression in neuroblastoma cells and are candidates as mediators of VIP gene expression in the intact animal.
Quisqualate‐ and NMDA‐sensitive [3H]glutamate binding in primate brain
Authors: Young A. B. , Dauth G. W. , Hollingsworth Z. , Penney J. B. , Kaatz K. , Gilman S. 
Published: January 2005

AbstractExcitatory amino acids (EAA) such as glutamate and aspartate are probably the neurotransmitters of a majority of mammalian neurons. Only a few previous studies have been concerned with the distribution of the subtypes of EAA receptor binding in the primate brain. We examined NMDA‐ and quisqualate‐sensitive [3H]glutamate binding using quantitative autoradiography in monkey brain (Macaca fascicularis). The two types of binding were differentially distributed. NMDA‐sensitive binding was most dense in dentate gyrus of hippocampus, stratum pyramidale of hippocampus, and outer layers of cerebral cortex. Quisqualate‐sensitive binding was most dense in dentate gyrus of hippocampus, inner and outer layers of cerebral cortex, and molecular layer of cerebellum. In caudate nucleus and putamen, quisqualate‐ and NMDA‐sensitive binding sites were nearly equal in density. However, in globus pallidus, substantia nigra, and subthalamic nucleus, quisqualate‐sensitive binding was several‐fold greater than NMDA‐sensitive binding. In thalamus, [3H]glutamate binding was generally low for both subtypes of binding except for the anterior ventral, lateral dorsal, and pulvinar nuclei. In the brainstem, low levels of binding were found, and strikingly the red nucleus and pons, which are thought to receive glutamatergic projections, had approximately 1/20 the binding observed in cerebral cortex.These results demonstrate that NMDA‐ and quisqualate‐sensitive [3H]glutamate binding are observed in all regions of primate brain, but that in some regions one subtype predominates over the other. In addition, certain areas thought to receive glutamatergic projections have low levels of both types of binding.
Passage of MHPG from plasma to CSF in a non‐human primate
Authors: Faull K. F. , Pascoe N. , Maddaluno J. , Greene K. A. , Wiener S. G. 
Published: January 2005

AbstractIn experimental protocols with humans and non‐human primates, cerebrospinal fluid (CSF) concentrations of 3‐methoxy‐4‐hydroxyphenylethylene glycol (MHPG), the predominant end‐product of norepinephrine metabolism in the mammalian central nervous system (CNS), have been widely used as an index of the rate of CNS norepinephrine metabolism. However, an earlier investigation showed that there was slow but free exchange between plasma and CSF MHPG. To define more precisely the time‐course of equilibration of plasma and CSF MHPG, we intravenously administered 100 μg/kg of [2H3]‐MHPG to drug‐naive squirrel monkeys. Measurements were made of the concentrations of [2H3]‐ and [1H]‐MHPG in plasma and cervical CSF samples collected at time points from 10 min to 4 hr thereafter. The results indicated that neither plasma nor CSF concentrations of [1H]‐MHPG changed during the course of the experiment, and that [2H3]‐MHPG appeared in the CSF within 10 min of intravenous administration. The maximal plasma and CSF concentrations of [2H3]‐MHPG were 7.6‐ and 2.3‐fold higher than the respective concentrations of [1H]‐MHPG. The plasma and CSF pools of [2H3]‐MHPG reached concentration equilibrium within 30 min, and thereafter the temporal decline in concentration of [2H3]‐MHPG was the same in plasma and CSF. These results demonstrate that MHPG rapidly crosses from plasma to CSF, and support the suggestion that this factor be included in any attempts to estimate norepinephrine turnover in the CNS from measurements of steady‐state MHPG concentrations in CSF or plasma.
Correlations of regional postmortem enzyme activities with premortem local glucose metabolic rates in alzheimer's disease
Authors: McGeer E. G. , McGeer P. L. , Harrop R. , Akiyama H. , Kamo H. 
Published: January 2005

AbstractCorrelations were sought between local cerebral metabolic rates (LCMRs) for glucose in various regions of the cortex, determined in premortem PET scans, with the regional activities of choline acetyltransferase (ChAT), acetylcholinesterase (AChE), β‐glucuronidase (Gluc, a probable index of reactive gliosis), and phosphate‐activated glutaminase (PAG, a possible indice of the large pyramidal neurons) measured on postmortem tissue. Significant negative correlations between LCMRs and Gluc activities were found in 6 PET‐scanned cases of Alzheimer disease (AD), and positive correlations of LCMRs with PAG were found in 5. By contrast, a positive correlation with ChAT and AChE was found in only 1. The results are consistent with the metabolic deficits in AD being primarily a reflection of local neuronal loss and gliosis. Similar data on two cases of Huntington's disease showed no significant correlations, while 1 patient with Parkinson dementia showed a significant (negative) correlation only with Gluc.
Localization of NGF receptors in normal and Alzheimer's basal forebrain with monoclonal antibodies against the truncated form of the receptor
Authors: Loy R. , Heyer D. , Clagett‐Dame M. , DiStefano P. S. 
Published: January 2005

AbstractFour new monoclonal antibodies to the extracellular domain of the nerve growth factor receptor (NGFR) have been evaluated for their specificity to NGFR and their utility in localizing NGFR in human brain. All four antibodies, as well as Me20.4, show similar cellular localization and patterns of immunoreactivity in basal forebrain neurons. NGFR monoclonal antibody XIF1 stains optimally over the widest range of concentrations, with staining being reduced only slightly at less than 10 pg/ml or more than 100 ng/ml, and produces the lowest background of those tested. Staining with all NGFR monoclonal antibodies is blocked by the addition of as little as 5‐fold excess human recombinant truncated NGFR protein. The distribution of NGFR‐containing neurons is similar to that previously described in normal human fore‐brain, as is the reduction in cell size in nucleus basalis (Ch4am) in brains from patients with Alzheimer's disease. In addition, we find evidence in the two Alzheimer's cases examined for a previously unreported loss of cells in the horizontal limb nucleus of the diagonal band (Ch3) in Alzheimer's disease. The loss of these neurons, which in normal brain have characteristic varicose dendritic processes extending to the pial surface adjacent to the cisternal space, may indicate a change in the relationship of NGF‐sensitive neurons to the vasculature. Since these neurons project to olfactory bulb and cortex in rodent and primate brains, their loss may also reflect damage to the olfactory system in Alzheimer's disease.