bluuebunny/crossref_metadata_2025_split huggingface dataset:
A new oligodendrocyte specific plasma membrane surface protein identified by a monoclonal antibody produced in vitro
Authors: Birling M.‐C. , Nussbaum F. , Nussbaum J.‐L. 
Published: January 2005

AbstractThis paper describes a novel monoclonal antibody (C1G5F2) derived from mice splenocytes immunized in vitro with a wheat germ agglutinin glycoprotein fraction isolated from bovine central nervous system (CNS) myelin. Immunohistochemical reactions with C1G5F2 were investigated on rat brain sections during the active period of myelination. From day 10 to 13 postnatally, no stained structures were observed throughout the whole brain. The first immunolabeled myelin fibers were detected within the pons at day 14, and the white matter areas in the cerebrum started to be stained some days later. White matter areas of the cerebellum were clearly immunopositive after the third week. There was a strong positive signal on myelin fibers in the cerebrum at day 30. By contrast, no immunolabeled cell bodies of oligodendrocytes were observed throughout the brain. The other neural cell types were also not labeled. This C1G5F2 monoclonal antibody bound mainly to the extracytosolic membrane surface of the processes of live cultured oligodendrocytes derived from newborn rat brain but was unreactive with live or fixed astrocytes and neurons maintained in culture. No immunostaining was detected in the peripheral nervous system or in the spleen, liver, or pancreas. The C1G5F2 epitope containing antigen may therefore be considered as a CNS myelin/oligodendrocyte specific molecule. Sodium deoxycholate‐Tween 20 extracts of secondary oligodendrocyte cultures, biotinylated with biotin hydrazide, were used to attempt the purification of the antigen with C1G5F2 IgMs linked to antimouse IgM agarose. A main broad biotinylated protein band of 54–58 kDa molecular mass was noted. In a second approach, the antigen was immunopurified from cultured oligodendrocytes as an immune complex using biotinylated C1G5F2 IgMs. A distinct protein doublet of 53–56 kDa was also observed. It is postulated that this antigen may play an essential role in myelin formation and could be a possible target in diseases restricted to CNS myelin. © 1994 Wiley‐Liss, Inc.
Toxic axonal degeneration occurs independent of neurofilament accumulation
Authors: Sickles D. W. , Pearson J. K. , Beall A. , Testino A. 
Published: January 2005

AbstractAlteration of neurofilament (NF) proteins is considered a critical component and a causative factor for a number of neuropathologies, especially certain neurotoxicities. Correlative observations have supported this hypothesis; the current study tests this relationship by exposure of neurotoxicants to crayfish, a species lacking NFs. Morphological and immunological tests verified the absence of NFs in crayfish peripheral nerve axons. Tail injections of acrylamide (ACR), 2,5‐hexanedione (2,5‐HD), or 3,4‐dimethyl‐2,5‐HD (3,4‐DMHD) produced ataxia and paralysis. Morphological expression of axonal degeneration in a spatial and temporal pattern of progression comparable to mammalian species possessing NFs was observed. With gamma‐diketones, time to onset was slower than observed in mammals but relative potency between neurotoxic analogues was maintained. Non‐neurotoxic analogues failed to produce any functional signs of neurotoxicity. These data are consistent with the conclusion that NF accumulations are not cause‐effect related to axonal degeneration in these models of neurotoxicity and raise questions as to the relationship between accumulation of NF proteins and axonal degeneration in other neuropathological conditions. Copyright © 1994 Wiley‐Liss, Inc.
Human IMR‐32 neuroblastoma cells as a model cell line in Alzheimer's disease research
Authors: Neill D. , Hughes D. , Edwardson J. A. , Rima B. K. , Allsop D. 
Published: January 2005

AbstractThe present study investigated expression and processing of amyloid precursor protein by neuronally differentiated IMR‐32 neuroblastoma cells. APP mRNA in these cells was found to consist of approximately 58% APP695, 38% APP751, and <4% APP770. APP‐immunoreactive bands detected in western blots of cellular protein extracts were only detected by anti‐APP antibodies to peptides with strong homology to APLP2, suggesting that these bands represent APP‐like proteins and not APP itself. This result suggests that previous studies claiming immunodetection of cellular forms of APP may have to be re‐evaluated. Four main species of C‐terminal truncated, secreted APP were detected in blots of protein extracts from medium conditioned by these cells. The immunoreactive profile of these bands suggested a cleavage site N‐terminal to the Lys16‐Leu17 bond of α‐secretase. This, together with differences in number and molecular mass of APP‐immunoreactive bands between secreted APP from IMR‐32 cells and that from the commonly used PC‐12 cells, suggests differences in APP processing between these two neuronally differentiated cell lines. In theory, IMR‐32 cells being of human neuronal origin may be a more appropriate cell line to study APP‐processing in relation to Alzheimer's disease than the rat phaeo‐chromocytoma PC‐12 cell line. Therefore, these detected differences warrant further investigation. Additionally IMR‐32 cells under certain tissue culture conditions can form intracellular fibrillary material that reacts with anti‐PHF specific antibodies. Neuronally differentiated IMR‐32 cells could therefore be used as a model system to investigate possible interactions between APP‐processing and PHF formation. © 1994 Wiley‐Liss, Inc.
Monoclonal antibody Alz‐50 reacts with bovine and human serum albumin
Authors: Davis P. K. , Johnson G. V. W. 
Published: January 2005

AbstractAlz‐50, a monoclonal antibody originally prepared using Alzheimer brain homogenates, reacts with PHF‐tau and normal tau on immunoblots, and stains specific neuronal populations in sections from Alzheimer's disease brain. Although the Alz‐50 epitope has been mapped to amino acids 2–10 present in all human tau isoforms, minimal Alz‐50 immunoreactivity is present in tissue from control brain, suggesting Alz‐50 binding may be dependent on tau conformational differences. The absence of conclusive results concerning Alz‐50 binding presents the possibility of Alz‐50 immunoreactivity with proteins other than tau. The present study demonstrates Alz‐50 crossreactivity with denatured bovine serum albumin (BSA) and human serum albumin (HSA). Using LA‐N‐5 neuroblastoma cells, BSA from serum‐containing media was present in cell homogenates and was found to be Alz‐50‐reactive on immunoblots. In fact, Alz‐50 (0.1 μg/ml) recognized as little as 78 ng of BSA and 312 ng of HSA. Since Alz‐50 does not recognize native BSA, blocking of immunoblots with 3% BSA did not alter Alz‐50 reactivity with tau from LA‐N‐5 cells. On SDS‐polyacrylamide gels, HSA (∼ 69 kDa) migrates very closely to the pattern of A68 (PHF‐tau) from Alzheimer brain homogenates. Hence, the presence of BSA or other albumins in cell or brain homogenates may be an important concern when using the Alz‐50 antibody. © 1994 Wiley‐Liss, Inc.
Neurite outgrowth and GAP‐43 mRNA expression in cultured adult rat dorsal root ganglion neurons: Effects of NGF or prior peripheral axotomy
Authors: Hu‐Tsai M. , Winter J. , Emson P. C. , Woolf C. J. 
Published: January 2005

AbstractAdult dorsal root ganglion (DRG) cells are capable of neurite outgrowth in vivo and in vitro after axotomy. We have investigated, in cultured adult rat DRG cells, the relative influence of nerve growth factor (NGF) or a prior peripheral nerve lesion on the capacity of these neurons to produce neurites. Since there is evidence suggesting that the growth‐associated protein GAP‐43 may play a crucial role in axon elongation during development and regeneration, we have also compared the effect of these treatments on GAP‐43 mRNA expression. NGF increased the early neurite outgrowth in a subpopulation of DRG cells. This effect was substantially less, however, than that resulting from preaxotomy, which initiated an early and profuse neurite outgrowth in almost all cells. No difference in the expression of GAP‐43 mRNA was found between neurons grown in the presence or absence of NGF over 1 week of culture, in spite of the increased growth produced by NGF. In contrast, cultures of neurons that had been preaxotomized showed substantial increase in GAP‐43 mRNA and NGF had, as expected, a significant effect on substance P mRNA levels. Two forms of growth may be present in adult DRG neurons: an NGF‐independent, peripheral nerve injury‐provoked growth associated with substantial GAP‐43 upregulation, and an NGF‐dependent growth that may underlie branching or sprouting of NGF‐sensitive neurons, but which is not associated with increased levels of GAP‐43 mRNA. © 1994 Wiley‐Liss, Inc.
Monoclonal antibody PHF‐1 recognizes tau protein phosphorylated at serine residues 396 and 404
Authors: Otvos L. , Feiner L. , Lang E. , Szendrei G. I. , Goedert M. , Lee V. M‐Y. 
Published: January 2005

AbstractThe microtubule‐associated protein τ is hyperphosphorylated in the paired helical filaments (PHFs) of Alzheimer's disease. Immunological and direct chemical studies have identified Ser396 and Ser404 as two of the phosphorylated sites. Previously, we have demonstrated, using synthetic τ peptides containing phosphorylated Ser396, that this site is recognized by the monoclonal antibody PHF‐1. The present sudy extends this observation by showing that PHF‐1 recognizes τ peptides containing either individually phosphorylated Ser396 or Ser404, but that there is a >10‐fold increase in the sensitivity of detection of τ peptides by PHF‐1 when both serines are phosphorylated. The recognition of singly or doubly phosphorylated Ser396 and Ser404 in τ by PHF‐1 can also be demonstrated in Chinese hamster ovary cells transfected with full‐length wild‐type τ constructs or mutant constructs with Ala substituted for Ser396 or Ser404. We conclude that the PHF‐1 epitope contains both phosphorylated Ser396 and Ser404. © 1994 Wiley‐Liss, Inc.
Reassembly of the 66 kD neurofilament protein in vitro following isolation and purification from bovine spinal cord
Authors: Balin Brain J. , Miller M. E. 
Published: January 2005

AbstractNF‐66, also known as α‐internexin, has been characterized as a 66 kD mammalian neurofilament (NF) protein whose expression in developing rat brain precedes that of the low molecular weight NF protein (NF‐L). NF‐66 is thought to assemble into 10 nm diameter intermediate filaments in vitro, although the precise nature of the assembly process remains obscure. Likewise, the ability of NF‐66 to polymerize with the low (NF‐L), middle (NF‐M), and high (NF‐H) MrNF proteins has not been defined. This investigation describes the reassembly of bovine NF‐66 regarding its formation into 10 nm diameter filaments as well as its potential for polymerization with other type IV intermediate filaments. NF‐66 and the NF triplet proteins were isolated from bovine spinal cord using established biochemical extraction and isolation procedures (Balin et al., Brain Res 556:181–195, 1991), and purified by a combination of high performance liquid chromatography (HPLC) (DEAE anion exchange and hydroxylapatite column chromatography) and gel elution strategies. In vitro reassembly experiments revealed that NF‐66 formed ˜ 10 nm diameter filaments of varying length; immunoelectron microscopy demonstrated labeling of these filaments by a monoclonal antibody to intermediate filament antigen (IFA), a polyclonal antibody against rat NF‐66 and by a monoclonal antibody generated against the core region of NF‐M but cross‐reactive with NF‐66. This report is the first investigation to look at the in vitro interaction between NF‐66 and other type IV intermediate filament proteins (NF‐H, ‐M, and ‐L) and establishes that NF‐66 forms heteropolymeric filaments with these other neurofilament proteins, as confirmed by double immunolabeling. These studies suggest that NF‐66 could provide a nucleation site for the polymerization of later‐expressed proteins during neuronal development. © 1995 Wiley‐Liss, Inc.
Macrophage recruitment in different models of nerve injury: Lysozyme as a marker for active phagocytosis
Authors: Venezie R. D. , Toews A. D. , Morell Pierre 
Published: January 2005

AbstractMacrophages play critical roles in both degenerative and regenerative processes following peripheral nerve injury. These include phagocytosis of debris, stimulation of Schwann cell dedifferentiation and proliferation, and salvage of myelin lipids for reutilization during regeneration. To better define the role of macrophages, we studied models of primary demyelination (tellurium intoxication) and secondary demyelination (nerve crush and cut). Sections of paraformaldehyde‐fixed rat sciatic nerves at various stages of demyelination were stained with monoclonal antibody ED1, a standard macrophage marker, and a polyclonal antiserum specific for lysozyme (LYS). Near the peak of demyelination in all three models, LYS immunoreactivity colocalized with ED1 staining. Macrophages present in nerve after the period of maximal phagocytosis of myelin were much less immunoreactive for LYS. These results suggest LYS is a good marker for macrophages which are active in phagocytosis. Tellurium intoxication, which causes synchronous demyelination and subsequent remyelination of only about 25% of myelin internodes, recruited more macrophages (and induced more lysozyme expression) than either nerve crush or cut, which cause demyelination of all internodes distal to the injury site. This suggests that Schwann cells may recruit macrophages soon after metabolic insult and prior to actual demyelination. The final signal for macrophage recruitment is not directly related to the amount of damaged myelin. In the models listed above, steady state mRNA levels for apolipoprotein E (ApoE; possible mediator of cholesterol salvage), LYS, and Po (major structural protein of PNS myelin), were analyzed by Northern blot analysis. LYS mRNA levels peaked sharply in all models, with a temporal pattern consistent with the expected presence of activated, phagocytic macrophages. The temporal pattern for ApoE mRNA levels differed in the 3 models, but ApoE expression was consistent with its proposed role in salvage of cholesterol during remyelination. © 1995 Wiley‐Liss, Inc.
Positive and negative effects of nuclear receptors on transcription activation by AP‐1 of the human choline acetyltransferase proximal promoter
Authors: Schmitt M. , Bausero P. , Simoni P. , Queuche D. , Geoffroy V. , Marschal C. , Kempf J. , Quirin‐Stricker C. 
Published: January 2005

AbstractWe have examined the 5′‐flanking region (944 bp) of the human choline acetyltransferase (hChAT) gene for sequences that modulate its transcriptional activity and identified a sequence 5′‐TGACCA‐3′ which confers c‐Jun/c‐Fos (AP‐1) inducibility of homologous and heterologous promoters. Using transient transfections in neuroblastoma NE‐1–115 and COS‐1 cells, we show that ligand‐activated estrogen receptor (HEGo) represses the transcriptional activation by c‐Fos/c‐Jun. Testing HEGo mutants in transfection assays reveals that the ligand‐binding domain is crucial for this repression, whereas the N‐terminal (A/B) region and the DNA‐binding domain are not essential. Gel retardation assays show that the hChAT AP‐1 recognition sequence binds in vitro baculovirus‐produced c‐Jun/c‐Fos proteins. This binding is inhibited by addition of baculovirus‐produced HEGo. In contrast to HEGo, ligand‐activated glucocorticoid, androgen, and retinoic acid receptors (RARs) enhance the transcription activation induced by c‐Jun/c‐Fos. All three types of RARs—RARα, β, γ—and RXRα are able to stimulate AP‐1 activity on the proximal hChAT promoter. Several mechanism possibilities involving protein‐protein interaction are discussed to explain the phenomena. © 1995 Wiley‐Liss, Inc.
Chromosomal assignment of the human gene for the cancer‐associated retinopathy protein (recoverin) to chromosome 17p13.1
Authors: McGinnis J. F. , Austin B. , Klisak I. , Heinzmann C. , Kojis T. , Sparkes R. S. , Bateman J. B. , Lerious V. 
Published: January 2005

AbstractThe gene for the mouse recoverin protein (23 kDa photoreceptor‐specific protein, S‐modulin, or the Cancer‐Associated Retinopathy protein) was recently assigned to mouse chromosome 11, closely linked to trp53. In this paper, the human gene for recoverin was localized to human chromosome 17 by Southern analysis of restriction digests of the DNA from mouse/human somatic cell hybrids. Using a 7 kb subclone of the human recoverin gene, a positive fluorescence in situ hyridization signal was demonstrated near the terminus of the short arm of chromosome 17 at position p13.1. The mapping of recoverin to this region of human chromosome 17, which contains a number of cancer‐related loci, suggests a possible mechanism by which cancer‐associated retinopathy occurs in humans. © 1995 Wiley‐Liss, Inc.
Apoptosis occurs in the oligodendroglial lineage, and is prevented by basic fibroblast growth factor
Authors: Yasuda T. , Grinspan J. , Stern J. , Franceschini B. , Bannerman P. , Pleasure David 
Published: January 2005

AbstractDuring the perinatal period, oligodendroglial precursor cells proliferate rapidly, then cease dividing and differentiate into oligodendroglia. Many of these newly formed oligodendroglia are destined to die. We now demonstrate that oligodendroglia generated in passaged cultures of rat forebrain oligodendroglial precursor cells after removal of basic fibroblast growth factor (basic FGF) from the medium often undergo internucleosomal DNA nicking and nuclear fragmentation, features characteristic of apoptosis. These alterations are rare in cultures maintained continuously in basic FGF. As in many other cellular lineages susceptible to apoptosis, these degenerative changes can be prevented by treatment with the endonuclease antagonist, aurintricarboxylic acid, or by inhibiting de novo RNA or protein synthesis. Supplementation of the basic FGF‐free medium with insulin, insulin‐like growth factor‐1, platelet‐derived growth factor, or ciliary neuronotrophic growth factor also diminishes DNA nicking. Both oligodendroglial differentiation and DNA nicking are induced in basic FGF‐treated cultures by inhibiting DNA synthesis with aphidicholin or excess thymidine, thus suggesting a close linkage between the anti‐apoptotic, anti‐differentiation, and mitogenic effects of basic FGF on the oligodendroglial lineage. © 1995 Wiley‐Liss, Inc.
Serotonin‐ and proton‐induced and modified ionic currents in frog sensory neurons
Authors: Philippi M. , Vyklický L. , Kuffler D. P. , Orkand Richard K. 
Published: January 2005

AbstractUsing the whole‐cell patch‐clamp technique, the effects of serotonin (5‐HT) and increased acidity to produce membrane currents and to modify high threshold voltage‐dependent calcium currents were studied in isolated dorsal root ganglion (DRG) cells of the frog maintained in short‐term culture. DRG cells were classified by morphology into two types: (1) cells with a large number of dark rusty brown granules, and (2) cells devoid of these granules or with few scattered pale granules. Fast application of 5‐HT (10–30 μM) induced a rapidly desensitizing inward current with a reversal potential at about 0 mV in 38 of 50 granule‐containing neurons (76%) which was never observed (0/35) in “clear” neurons. This current was blocked by 10 nM (+)‐tubocurarine. In addition, a small noninactivating outward current was also observed in most DRG neurons during 5‐HT superfusion. A sudden decrease of pH from 7.4 to 6 or 5.8 induced a fast inactivating inward current of 100–300 pA in 74% of the “clear” neurons and only 24% of the granule‐containing neurons. Small noninactivating membrane currents induced by lowering pH were observed in all neurons. Both 5‐HT and increased extracellular H+ reduced the magnitude of high threshold calcium currents in all DRG neurons. It is suggested that the 5‐HT receptors are expressed on a morphologically distinct population of neurons while the cells with channels responsible for the fast inactivating proton‐induced current cannot be related to any distinct morphological cell type. © 1995 Wiley‐Liss, Inc.
Nitric oxide‐sensitive protein ADP‐ribosylation is altered in rat diabetic neuropathy
Authors: Gorio Alfredo , Donadoni M. L. , Di Giulio A. M. 
Published: January 2005

AbstractEndogenous ADP‐ribosylation of proteins was studied in retina crude extract, membrane and cytosolic fractions of control and diabetic rats. ADP‐ribosyl‐transferase activity is present in all cellular fractions, but protein ADP‐ribosylation is reduced in diabetic rat retina. At least 6 proteins are labelled in the crude extract fraction and a similar number in the membrane preparation of control animals. In these preparations from diabetic retina, only two bands were labelled, the 85 K and 36K for the crude extract, and the 97 K and 39 K for membranes. Labelling of 36 K and 39 K proteins was much less than in controls. In the cytosolic preparations of controls, two proteins of 85 K and 39 K are ADP‐ribosylated, while in diabetic rat retina cytosol, only the 85 K is labelled. Treatment of diabetic rats with insulin normalized plasma glucose levels and prevented the alterations of the extent of ADP‐ribosylation for the 38 K cytosolic, 39 K membrane and 36 K crude extracts proteins, but it failed to affect the other bands. These results suggest a hyperactivity of endogenous ADP‐ribosylases in diabetic rat retina, so that the protein sites for ADP‐ribosylation are no longer available. Since insulin treatment prevents the onset of neuropathy and of retinal G protein impairment (Abbracchio et al., J Neurosci Res 29:196–220, 1991) in diabetic rats and, in this study, normalizes ADP‐ribosylation of 39 K, 38 K and 36 K proteins, we suggest that the abnormal endogenous ADP‐ribosylation of these proteins might play a role in the onset of diabetic neuropathy. © 1995 Wiley‐Liss, Inc.
Recognition molecules myelin‐associated glycoprotein and tenascin‐C inhibit integrin‐mediated adhesion of neural cells to collagen
Authors: Bachmann M. , Conscience J.‐F. , Probstmeier R. , Carbonetto S. , Schachner Melitta 
Published: January 2005

AbstractBecause of the importance of collagens in mediating cell‐substrate interactions and the association of collagens with neural recognition molecules in the peripheral nervous system, the ability of neural recognition molecules to modify the substrate properties of collagens, in particular collagen type I, for cell adhesion was determined. Two cell lines, the N2A neuroblastoma and PC12 pheochromocytoma, were investigated for their capacity to adhere to different collagen types in the absence or presence of several neural recognition molecules. Adhesion of N2A or PC12 cells and membrane vesicles from PC12 cells to collagen type I was reduced when the collagen had been preincubated prior to its application as substrate with the extracellular domain of myelin‐associated glycoprotein (s‐MAG) or, as control, fibroblast tenascin‐C (F‐tenascin). In mixture with other collagen types, s‐MAG was only able to reduce the adhesiveness of collagen types III and V, but not of collagen types II and IV. F‐tenascin reduced the adhesiveness of all collagen types tested. In contrast to F‐tenascin, s‐MAG had to be present during fibrillogenesis to exert its effect, indicating that it must be coassembled into the collagen fibril to block the cell binding site. Cell adhesion to collagen type I was dependent on Mg2+ or Mn2+ and inhibited by a monoclonal antibody to the α1 integrin subunit. The combined observations indicate that s‐MAG and F‐tenascin interfere with cell binding, most probably by modifying the integrin binding site, and that the two molecules act by different mechanisms, both leading to reduction of adhesion. © 1995 Wiley‐Liss, Inc.