bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chicken NGF and Non‐NGF trophic factor synthesis and release by sciatic nerves in vitro
Authors: Ferguson I. A. , Williams R. , Rush R. A. 
Published: January 2005

AbstractThe time course of production and release of nerve growth factor (NGF) and non‐NGF neuronotrophic factors for sympathetic neurons by chicken and rat sciatic nerves in culture was examined. These tissues actively synthesize and release neuronotrophic activity as metabolically poisoning nerves with azide dramatically reduced the amount of trophic activity released into the culture medium. The sustained release of this activity also was shown to be dependent on the presence of low‐molecular‐weight dialysable molecules present in foetal calf serum and amniotic fluid from day 11 chicken embryos. Affinity‐purified antimouse NGF antibodies were used to show that sciatic nerves in culture release both NGF and non‐NGF trophic factors. These antibodies inhibited all bioactivity of both mouse NGF and of a partially purified preparation of chicken NGF. Immunoblot studies confirm that the antibodies recognize both rodent and avian NGF. Excess antibody inhibited only about 50% of the trophic activity in media conditioned over rat or chicken nerves for the first 24 hr. Relatively similar amounts of this non‐NGF trophic activity were released throughout 6 days in culture, and this trophic activity kept sympathetic neurons alive in culture in the absence of NGF for more than 4 days. NGF levels were quantified with a two‐site enzyme‐linked immunoassay and found to parallel changes in NGF bioactivity. Rat nerves released increasing amounts of NGF with time in culture. Whole chicken sciatic nerves, however, released decreasing amounts of NGF with time in culture, but when these nerves were desheathed by removal of the epineurium and attached tissue, the pattern of NGF release was similar to that observed in the smaller rat sciatic nerves. These studies therefore characterize antibodies recognising chicken NGF, demonstrate that peripheral nerve tissue synthesize trophic factors other than NGF, and identify factors that influence NGF synthesis.
Effect of nerve growth factor on the synthesis of amino acids in PC12 cells
Authors: Zielke H. R. , Tildon J. T. , Kauffman F. C. , Baab P. J. 
Published: January 2005

AbstractRadioactive short‐chain fatty acids preferentially label glutamine relative to glutamate in brain due to compartmentation of glutamine and glutamate. To determine whether this phenomenon occurs in a single cell culture model, we examined the effect of fatty acid chain length on the synthesis as well as pool size of selected amino acids in rat pheochromocytoma PC12 cells, a cell culture model of the large glutamate compartment in neurons. Intracellular 14C‐amino acids were quantitated by HPLC, and the incorporation of [U‐14C]‐glucose, [1minus;14C]‐butyrate, [1‐14C]‐octanoate, and [1‐14C]‐palmitate into five amino acids was measured in native and NGF‐treated PC12 cells. NGF pretreatment decreased the intracellular concentration of amino acids as did addition of fatty acids but these effects were not additive. Specific activities of amino acids in native cells labelled by 14C‐octanoate were 1,300 DPM/nmol, 490 DPM/nmol, 200 DPM/nmol, and 110 DPM/nmol for glutamate, aspartate, glutamine, and serine, respectively. No radioactivity was detected in alanine. Similar specific activities were noted when 14C‐butyrate was the precursor; however, there was at least 5‐fold less if 14C‐palmitate was the precursor. Pretreatment of cells with NGF decreased the specific activity of amino acids by 25–65%. Specific activities of amino acids synthesized from 14C‐glucose decreased in the following order: glutamate, 1,640 DPM/nmol; aspartate, 1,210 DPM/nmol; alanine, 580 DPM/nmol; glutamine, 275 DPM/nmol; and serine, 80 DPM/nmol for native cells. NGF pretreatment decreased the specific activities of glutamate and glutamine, but not of the other 3 amino acids. The preferred precursor for glutamate synthesis in native PC12 cells was glucose followed by octanoate, butyrate and palmitate (16:6:3:1).
Nerve regulation of class I and Class II‐asymmetric forms of acetylcholinesterase in rat skeletal muscles
Authors: Fadić R. , Inestrosa N. C. 
Published: January 2005

AbstractTwo classes of collagen‐tailed, asymmetric forms (A‐forms) of acetylcholinesterase (AChE) have been described in skeletal muscles of vertebrates. They are distinguished by their different solubilization requirements: class I A‐forms are solubilized in the presence of high salt, whereas class II A‐forms require in addition a chelating agent for solubilization. We report here that class II A‐forms are less sensitive to nerve section than are class I A‐forms. The latter form decreases faster and to a lower level of activity after denervation. The decay of both AChE classes is more rapidly in short‐stump nerves than in long ones. The effect of nerve section on class II A‐forms appears to be dependent on the particular muscle group being studied. Both classes of A‐forms reappear after muscle reinnervation, but the class I A‐forms recovered earlier. More interestingly, both classes of A‐forms increase in normally innervated skeletal muscles after contralateral nerve injury. In this case, however, the class II A‐forms change first. Muscular disuse induced by contralateral tenotomy is also followed by a rise in class II A‐forms. Our results, showing differences in response and flexibility in the changes of the two classes of A‐forms in several experimental conditions, represent a relevant contribution to the understanding of the regulation and functional role of the asymmetric forms of AChE in vertebrate skeletal muscles.
Induction of protooncogene fos by extracellular signals in primary glial cell cultures
Authors: Condorelli D. F. , Kaczmarek L. , Nicoletti F. , Arcidiacono A. , Dell'Albani P. , Ingrao F. , Magrì G. , Malaguarnera L. , Avola R. , Messina A. , Stella A. M. Giuffrida 
Published: January 2005

AbstractIn the present study various extracellular factors, acting through different second messenger systems, were examined for their capacity to increase the level of c‐fos mRNA in primary glial cell cultures. In particular EGF, 12‐O‐tetradecanoylphorbol 13‐acetate, the beta‐adrenergic agonist isoproterenol, and the glutamate agonists, ibotenic and quisqualic acid, were studied. All the extracellular stimuli tested induced a rapid and transient increase in c‐fos mRNA level in glial cell cultures regardless of the signal transduction pathway and the final effect on cell proliferation.
Immunohistochemistry with anti‐calbindin and anti‐neurofilament antibodies in the cerebellum of methylazoxymethanol‐treated mice
Authors: de Barry J. , Gombos G. 
Published: January 2005

AbstractMice pups were injected with methylazoxymethanol at birth (MAM0) or on the fifth postnatal day (MAM5) and their cerebella were examined when adult. Immunohistochemistry with an antiserum directed against calbindin, a protein specific for Purkinje cells, was used to survey more easily Purkinje cell position and orientation. For a general view of basket cell axon distribution, we used a monoclonal antibody that recognized the phosphorylated form of the 200 kD constituent protein of neurofilaments, which is axon specific. The present results confirm that in MAM5 the cytoarchitecture was preserved, some Purkinje cells degenerated, and the pericellular basket around the Purkinje cells was apparently normal. In MAM0 animals, the Purkinje cells appeared malpositioned and disoriented, the pinceau around the Purkinje cell hillock was absent, but basket cell axons were present. This indicated that the absence of pinceau was not due to the absence of basket cells, but probably to alterations of cell interactions, which hindered the proper pericellular basket formation.
Human brain microvascular DR‐antigen
Authors: Pardridge W. M. , Yang J. , Buciak J. , Tourtellotte W. W. 
Published: January 2005

AbstractAntigen presentation within the human central nervous system by the class II histocompatibility DR‐antigen may take place at either the brain capillary–endothelial interface or at perivascular cells, such as smooth muscle or pericytes. The present studies employ a new sensitive immunoperoxidase technique, a mouse monoclonal antibody to the human DR‐antigen, and microvessels isolated from autopsied human brain. The experiments show that the DR‐antigen is readily detectable in human microvasculature of normal brain and is found in the smooth muscle pre‐capillary arterioles and capillary pericytes with minimal, if any, staining of capillary endothelium. These results are consistent with the hypothesis that antigen presentation in the CNS occurs primarily at a site immediately distal to the blood–endothelial interface.
Indole amine deficiency in blood and cerebrospinal fluid from patients with human immunodeficiency virus infection
Authors: Larsson M. , Hagberg L. , Norkrans G. , Forsman A. 
Published: January 2005

AbstractTwenty‐four patients with human immunodeficiency virus (HIV) infection were investigated for possible changes in certain indole amine constituents in blood and cerebrospinal fluid (CSF). Albumin in serum was determined and used as a rough nutritional marker. Six of the 24 patients had acquired immunodeficiency syndrome AIDS, four had other clinical symptoms of HIV infection, and 14 had no apparent symptoms. The HIV‐seropositive patients had significantly decreased tryptophan values; their blood concentrations were 28% lower and their CSF concentrations 30% lower than corresponding values in 14 healthy controls. The blood concentrations of 5‐hydroxytryptamine (5‐HT) were 50% lower, and the platelet content of 5‐HT was 36% lower in HIV‐infected individuals than in the control group. The most pronounced changes were invariably seen in the six cases with AIDS and in patients with a low number of CD4+ cells. No significant difference between controls and HIV‐seropositive patients was detected in the mean CSF concentrations of 5‐hydroxyindoleacetic acid (5‐HIAA), although these levels were markedly reduced in four of the HIV patients. Neither was any significant difference seen between patients and controls in the serum concentrations of albumin.
Functional expression of the yes proto‐oncogene protein in Xenopus oocytes injected with chicken cerebellar mRNA
Authors: Sudol M. 
Published: January 2005

AbstractUsing monospecific antibodies raised against the amino terminal domain of viral‐yes protein, we precipitated a 58 kD protein‐tyrosine kinase from the brain of Xenopus laevis frog. By a number of criteria, including pattern of expression in various tissues and one‐dimensional peptide mapping, we concluded that pp58 is very likely the authentic amphibian yes protein because it is more similar to the chicken yes protein than to any other known tyrosine kinases. The pp58c–yes is expressed in adult brain at elevated levels. In contrast, its level of expression in follicular and denuded oocytes is 30–50 times lower. Because of the low endogenous expression of the oocyte‐associated yes kinase, we were able to transiently express and analyze pp62c‐yes by injecting oocytes with 27S size fraction of poly(A)+ mRNA isolated from chicken cerebella. The pp62c‐yes expressed in oocytes from the exogenous message comigrated on SDS polyacrylamide gel with pp62c‐yes from cerebellum and was indistinguishable from it by one‐dimensional peptide mapping. The pp62c‐yes expressed in oocytes was enzymatically active. A number of phosphotyrosine‐containing proteins were detected specifically in the c‐yes mRNA‐injected oocytes. The usefulness of the Xenopus oocyte expression system to study the functional aspects of c‐yes protein and other tyrosine kinases was evaluated.
X‐ray diffraction analysis of myelin lipid/proteolipid protein multilayers
Authors: Brown F. R. , Karthigasan J. , Singh I. , Kirschner D. A. 
Published: January 2005

AbstractTo examine the proposal that myelin proteolipid protein underlies the adhesion of neighboring membranes in central nervous system (CNS) myelin, we carried out X‐ray diffraction studies on the structure and interactions of model bilayers composed of total myelin lipids plus proteolipid apoprotein (PLP). Total myelin lipids were used because their heterogeneity was expected to provide an appropriate environment for the integral membrane protein to achieve its native conformation and establish appropriate contacts with the apposed bilayer.We found that incorporation of PLP into myelin lipid bilayers, whether organized into multilamellar vesicles or oriented multilayers, did not appreciably affect the lamellar period, which ranged from 65–71 Å. In oriented multilayers, the wide‐angle spacing at ≈4.8 Å, which arises from the lateral packing of lipid chains and is perpendicular to the lamellar diffraction, was less oriented and weaker in bilayers containing the protein. These results indicate that PLP was incorporated into the bilayers and had a disordering effect on the hydrocarbon chains but did not extend into the spaces between bilayers. Bilayer profiles calculated from the lamellar diffraction to about 15 Å spacing did not show any major changes in the distribution of electron density, suggesting that to moderate resolution, the protein was distributed uniformly across the width of the lipid bilayer. Periodicities measured from osmotically stressed multilamellar vesicles did not depend on the presence of PLP, indicating that the protein did not form stabilizing contacts between bilayers. We suggest that the results of structural, biophysical, and functional studies on model bilayers containing proteolipid protein may not extrapolate to the in vivo interactions of myelin because it is unlikely that the protein is in its native conformation.
Defective T helper cell epitope responsible for the failure of region 69–84 of the human myelin basic protein to induce experimental allergic encephalomyelitis in the lewis rat
Authors: Hashim G. A. , Galang A. B. , Srinivasan J. V. , Carvalho E. F. , Offner H. , Vandenbark A. A. , Cleveland W. L. , Day E. D. 
Published: January 2005

AbstractStudies from our laboratory have shown that region 69–84 (synthetic peptide S49S) of myelin basic protein (MBP) defines an encephalitogenic sequence for experimental allergic encephalomyelitis (EAE) in Lewis rats. The most potent EAE inducers are the guinea pig MBP (Gp‐MBP) and region 69–84, known as synthetic peptide Gp‐S49S:
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Human (H‐MBP) was considerably less potent than Gp‐MBP, and region 69–84 (H‐S49S) of H‐MBP did not induce hind leg paralysis or any histological signs of EAE. Since the development of EAE requires the expression of specific T and B cell epitopes, sequence analysis of H‐S49S and Gp‐S49S revealed phylogenetic variations in the H‐S49S sequence, characterized by deletion of Gln (No.76), insertion of His‐Gly at positions 77 and 78, and substitution of Ser with Thr at position 80:
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Like Gp‐S49S, peptide H‐S49S induced the formation of antibodies with specificities directed against the C‐terminal of the H‐S49S, Gp‐S49S, and homologous sequences. In contrast to Gp‐S49S, neither H‐S49S nor shorter peptides induced clonal T cell expansion when either of the peptides was added to encephalitogenic T cell clone D in culture. Clone D, which expresses T helper phenotype, was selected from encephalitogenic peptide‐primed Lewis rats. The results of the study show that the failure of H‐S49S to induce EAE is related to sequence alterations in the T helper cell epitope but not in the B cell epitope located in the N‐ and C‐terminal portions of the S49S sequence, respectively. Also, the results suggest that the EAE activity of H‐MBP may be related to either a second EAE region that expresses T helper and B cell functions or to a dislocated T helper cell epitope that operates in conjunction with the B cell epitope located in the C‐terminal region of the H‐S49S sequence.
Ethanol alters the transfer of arachidonic acid to ethanolamine plasmalogens in C‐6 glioma cells
Authors: Sun G. Y. , Aradottir S. , Gustavsson L. , Alling C. 
Published: January 2005

AbstractIn this study, the effects of ethanol exposure on uptake and metabolism of arachidonic acid by C‐6 glioma cells in culture was examined. Labeled arachidonic acid was effectively taken up by the phospholipids of these cells and radioactivity was initially incorporated into phosphatidylinositols and phosphatidylcholines, reaching a peak between 4 and 6 hours. However, the labeling of ethanolamine plasmalogens continued to show an increase with time after labeled arachidonic acid has been exhausted in the medium. Since over 90% of labeled arachidonic acid was already taken up by the cells after 4 hours of exposure, the continued increase in labeling of ethanolamine plasmalogens is attributed to a transacylation mechanism. Cells grown in 150 mM ethanol for 2 days did not show a change in the overall incorporation of labeled arachidonic acid into phospholipids but showed a significant increase in labeling of ethanolamine plasmalogens, which was marked by a concomitant decrease in labeling of phosphatidylcholines. Ethanol exposure also resulted in a significant increase in the transfer of labeled arachidonic acid to triacylglycerols. Changes in phospholipid and triacylglycerol labeling pattern positively correlated with increasing ethanol concentration from 75 to 300 mM. Besides, most ethanol effects were readily noticeable after 24 hours of exposure. These data suggest a specific effect of ethanol on promoting the transacylase process for biosynthesis of ethanolamine plasmalogens as well as the acyltransferase for biosynthesis of triacylglycerols.
Effect of repeated electroconvulsive treatment on regional concentrations of tachykinins, neurotensin, vasoactive intestinal polypeptide, neuropeptide Y, and galanin in rat brain
Authors: Stenfors C. , Theodorsson E. , Mathé A. A. 
Published: January 2005

AbstractThe effects of single and repeated electroconvulsive treatments (ECTs) on brain regional distribution of substance P (SP), neurokinin A (NKA), neurotensin (NT), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), and galanin (GAL) were studied in the rat. Rats were divided into four groups receiving one of the following treatments: one ECT, one sham ECT, six ECTs, or six sham ECTs. After sacrifice by focused microwave irradiation, brains were dissected into frontal cortex, striatum, occipital cortex, hippocampus, hypothalamus, and pituitary sections. Peptides were extracted by boiling the tissues in 1 mol/l acetic acid and measured in extract aliquots by specific radioimmunoassays. Marked regional differences (P =.0005) were found for each of the peptides measured. The highest concentrations of SP and NKA were found in the hypothalamus and, in descending order, in striatum, pituitary, frontal cortex, occipital cortex, and hippocampus. For NT, the highest level was found in the hypothalamus and, in descending order, in pituitary, striatum, hippocampus, frontal cortex, and occipital cortex. The highest VIP concentrations were measured in frontal and occipital cortex, followed by pituitary, hypothalamus, striatum, and hippocampus. The highest NPY and GAL concentrations were found in the hypothalamus and the pituitary; in frontal and occipital cortex, as well as in the striatum and hippocampus, the peptides levels were rather evenly distributed. Repeated handling (stress?) decreased both NT and GAL in frontal (P =.05 and.04) and occipital cortex (P =.09 and.07). ECT, one or six treatments, had no effect on SP, NKA, NT, VIP, or GAL concentrations in different brain regions. However, an increase in NPY concentrations in hippocampus (six sham ECTs vs. six ECTs = right: 112 ± 61 vs. 246 ± 159, and left: 143 ± 42 vs. 303 ± 160 pmol/g; P =.0005) and occipital cortex (right: 118 ± 42 vs. 167 ± 98; and left: 97 ± 45 vs. 157 ± 42 pmol/g, P =.003) was obtained after six ECTs but not following a single treatment. The results demonstrate a regional effect of ECT on NPY and raise the possibility that one of the ECTs' modes of action may be by elevating NPY levels in the CNS.
Sequence of a human MAP‐2 region sharing epitopes with Alzheimer neurofibrillary tangles
Authors: Dammerman M. , Yen S.‐H. , Shafit‐Zagardo B. 
Published: January 2005

AbstractMicrotubule‐associated protein 2 (MAP‐2), an abundant neuronal protein, consists of a short microtubule‐binding domain and a long projection arm. MAP‐2 shares epitopes with Alzheimer neurofibrillary tangles (NFT). However, most anti‐MAP‐2 antibodies do not stain detergent‐extracted NFT, and the role of MAP‐2 in NFT formation has therefore been unclear. We have determined the sequence of a 1.7 kb partial MAP‐2 cDNA encoding at least three NFT epitopes. The epitopes are not removed by detergent extraction of tangle preparations, suggesting that they are integral components of NFT. Expression vectors containing restriction fragments of the cDNA were used to assign the epitopes to a 51‐amino‐acid region near the end of the MAP‐2 projection arm, distal to the microtubule.
Neurite‐promoting influences of proliferating schwann cells and target‐tissues are not prerequisite for rapid axonal elongation after nerve crush
Authors: Bresjanac M. , Sketelj J. 
Published: January 2005

AbstractAn important role in peripheral nerve regeneration has been ascribed to humoral trophic and tropic agents arising from the nonneuronal cells in the distal nerve stump and the denervated targets. In order to estimate their contribution to axonal elongation after crush injury to the rat sciatic nerve, an in vivo model was designed in which local cellular and target‐derived influences were eliminated by (1) freeze‐thawing of a long nerve segment distal to the crush site and (2) cutting the nerve far distally to the crush site, but within the frozen‐thawed segment, and deflecting the frozen‐thawed nerve stump in the opposite direction from its natural course.The sensory and motor axon elongation rate was estimated from the results of the nerve pinch test and choline acetyltransferase distribution along the nerve segment distal to the crush.The elongation rate of regenerating axons in deflected nerve segments, either non‐treated or frozenthawed, was close in magnitude to that obtained when target‐derived influences were not eliminated. Neurotropism of axonal targets is therefore of little importance for axon elongation after nerve crush. In the absence of Schwann cells along the axonal path in frozen‐thawed nerve segments, the elongation rate of both sensory and motor axons declined by about 40%. This implies that interactions between viable Schwann cells and growth cones of regenerating axons are not prerequisite for rapid axon elongation when Schwann cell basal lamina constitutes the growth substratum. Nevertheless, Schwann cells in Bungner bands possibly enhance the axon elongation rate by humoral or cell surface‐mediated mechanisms.