bluuebunny/crossref_metadata_2025_split huggingface dataset:
Peanut agglutinin binding glycoproteins in the chick retina: Their presence in Müller glia cells
Authors: Arregui C. , Barra H. S. , Landa C. A. 
Published: May 2005

AbstractThe histological and cellular distribution and some biochemical characteristics of components that bind peanut agglutinin (PNA), a lectin that recognizes preferentially terminal galactose‐β (1–3) N‐acetyl galactosamine disaccharide residues of glycoconjugates, were studied in chick retinal tissue and in dissociated retinal cells after their differentiation in culture. In sections of retinal tissue from animals 7 days after hatching (Rp7), in addition to the inner and outer segments of the photoreceptor layer, the plexiform and optic fiber layers were stained with rhodamine‐labeled PNA, indicating that, besides photoreceptor cells, other cellular types contribute to the PNA staining. We present evidence indicating that at least part of this staining is provided by Müller glia cells. In cultures of dissociated cells from retinas at embryonic day 7 (R7), photoreceptor‐like cells and flat Müller glia‐derived cells but not neurons were stained with rhodamine‐labeled PNA. Furthermore, Müller glia cells isolated from Rp7 were also brightly stained with PNA. Western blot assays of extracts from R7 showed the presence of PNA binding glycoproteins of 31–33 kDa and a component that migrates at the dye front. In addition to the components detected in R7, extracts from R14 and Rp7 showed the presence of a major PNA binding glycoprotein of 175 kDa and a minor glycoprotein of 220 kDa. Extracts from the photoreceptor layer contain the 175 and 220 kDa glycoproteins, indicating their association with photoreceptor cells. The 31–33 kDa components were detected in extracts from the remnant inner retina, suggesting their association with the Müller glia cells. Supporting this view, these components and not those of 175 and 220 kDa were detected in cell cultures enriched in flat Müller glia‐derived cells. Only the 31–33 kDa components and the component that migrates at the dye front were detected in extracts from cell cultures enriched in photoreceptor‐like cells, suggesting the need of some environmental element for the expression of the 175 and 220 kDa components in the differentiated photoreceptor cells.
Heptyl‐physostigmine enhances basal forebrain control of cortical cerebral blood flow
Authors: Linville D. G. , Giacobini E. , Arnerić S. P. 
Published: May 2005

AbstractThis study sought to determine the effect of heptylphysostigmine (H‐PHY), a reversible cholinesterase (ChE) inhibitor with greater lipophilicity and longer duration of action than physostigmine, on resting and basal forebrain (BF)‐elicited increases in cortical cerebral blood flow (CBF). Laser‐doppler flowmetry (LDF) was used to monitor changes in frontal cortical microvascular perfusion in urethane anesthetized rats. Responses were measured before, early after, and 1 hr following H‐PHY, 3 mg/kg, i.m. Electrical stimulation (100 μA) of the BF elicited up to 220% increases in CBF at 50 Hz, an effect that was graded with frequency. At 15 min following H‐PHY (3 mg/ kg) resting cortical CBF was unchanged, whereas BF‐elicited increases were potentiated 47% at 50 Hz. At 1 hour, resting cortical CBF remained unchanged, and the BF‐elicited responses were remarkably potentiated by 354% at 10 Hz and 67% at 50 Hz. Acetylcholinesterase (AChE) activity measured in the tissue directly beneath the LDF probe was decreased by 84% at a time when these CBF responses were enhanced. These data suggest that H‐PHY substantially enhances the regulation of cortical CBF by the BF, an effect that may be linked to inhibition of cortical AChE activity. This enhancement of cortical CBF may contribute to the efficacy of H‐PHY as a treatment for Alzheimer' disease.
Transient, cyclic changes in mouse visual cell gene products during the light‐dark cycle
Authors: McGinnis J. F. , Whelan J. P. , Donoso L. A. 
Published: May 2005

AbstractTemporal and spatial changes in the cellular and sub‐cellular concentrations of photoreceptor cell gene products appear to be important features of pho‐totransduction in rod photoreceptor cells. The time course of the rapid, light‐dependent movement of S‐antigen (S‐Ag) (48k; Arrestin) from the inner segments to the outer segments was analyzed using poly‐clonal and monoclonal antibodies. The concentrations of mRNA change about threefold for rhodopsin and about sixfold for S‐Ag in cyclic, independent modes during the normal light‐dark cycle. Kinetic analysis indicates that the oscillations of S‐Ag mRNA levels are due to changes in the transcriptional activity of the gene itself. An experimental model is presented summarizing the relationships between mRNA levels, protein localization, disc shedding, and phototransduction in the photoreceptors cells.
Purified cultures of keratin‐positive olfactory epithelial cells: Identification of a subset as neuronal supporting (Sustentacular) cells
Authors: Pixley S. K. 
Published: May 2005

AbstractThe mammalian olfactory neuroepithelium, lining part of the nasal cavity, retains into adulthood progenitor cells for the olfactory receptor neurons and other cell types in the epithelium. The details of cellular lineage relationships are not completely under stood. In particular, the exact nature of the interactions between several progenitor cell types and their relationship to neurons is not known. Studies of this system have been hampered by the lack of cell culture models and insufficient cell‐type‐specific markers. Antibodies to the cytokeratins are fairly specific markers for one potential progenitor cell type, the dark basal cells of the olfactory epithelium. Keratin immunostaining was used to develop cell culture systems which contained large numbers of putative dark basal cells, using the soft nasal mucosal tissues of both newborn and adult rats. Media and substrate conditions were optimized. The conditions which sup ported growth of keratin‐positive nasal cells for greater than one month, and allowed partial purification, suggested similarities between olfactory and skin keratinocytes. Immunostaining with a monoclonal antibody specific for sustentacular cells (SUS‐1) showed a subset of these cells present in culture, with some cells double‐labelled with anti‐keratin. This staining confirms the olfactory origin of at least a subset of the cells, and supports the proposal that the majority of cells were the dark olfactory basal cells. This culture system gives novel insights into olfactory epithelial cell physiology, and allows culture of these cells for further studies examining regulation of differentiation.
Calcium‐activated neutral proteinase (calpain) activity in C6 cell line: Compartmentation of μ and m calpain
Authors: Banik N. L. , Chakrabarti A. K. , Konat G. W. , Gantt‐Wilford G. , Hogan E. L. 
Published: May 2005

AbstractCalcium‐activated neutral proteinase (calpain) activity was determined, including in cytosol and membrane fractions, in rat glioma C6 cell line. The μ and m forms of calpain were separated by DEAE and phenylsepharose column chromatography and with removal of the endogenous inhibitor calpastatin. C6 cells contained more mcalpain than the μ isoform. More than 70% of mcalpain activity was membrane‐associated and 20% was cytosolic. Isolated plasma membrane also contained 69% of the mcalpain activity. In contrast, approximately 80% of μcalpain activity was cytosolic and 16% was membranous. Half‐maximal activity for μ and mcalpain was obtained at 1 μM and 0.2 mM CaCl2, respectively. Trypsin dissociation of cells reduced activity. Triton X‐100 stimulated mcalpain activity of the whole homogenate and the membrane pellet but not of the cytosol. Activity of the myelin marker enzyme adenosine 2′3′‐cyclic nucleotide 3′‐phosphohydrolase (CNPase), was also found in C6 cells. The identification of calpain and CNPase in C6 cells is in keeping with an interpretation that C6 differentiation resembles, at least in part, that of the myelin‐forming oligodendroglial cells.
Decorin, a chondroitin/dermatan sulfate proteoglycan is under neural control in rat skeletal muscle
Authors: Brandan E. , Fuentes M. E. , Andrade W. 
Published: May 2005

AbstractProteglycans (PGs) are abundant components of the extracellular matrices (ECM) of skeletal muscle. We have previously found that the synthesis of skeletal muscle PGs present at the ECM increase after denervation. The experiments reported here were undertaken to identify which PG(s) increase after denervation of rat leg muscles. Incorporation of ra‐dioactive sulfate demonstrated the presence of a chondroitin/dermatan sulfate PG of 70–90 kDa in the skeletal muscle ECM, which increased after denervation. The PG has a core protein of 39–45 kDa after treatment with chondroitinase ABC. Antibodies against rat decorin, a chondroitin/dermatan sulfate PG synthesized by various cell types, specifically immunoprecipitated this PG from a mixture of PGs. Immunocytolocalization of this PG indicated that the chondroitin/dermatan sulfate PG accumulates at the perimysium of skeletal muscle after denervation. Finally, Northern blot analysis indicated an increase of muscle transcripts for decorin after denervation. The data reported here suggest that a chondroitin/dermatan sulfate PG present at the skeletal muscle ECM, very similar if not identical to decorin, increases after denervation. © 1992 Wiley‐Liss, Inc.
Oligodendrocyte‐substratum adhesion activates the synthesis of specific lipid species involved in cell signaling
Authors: Vartanian T. , Szuchet S. , Dawson Glyn 
Published: May 2005

AbstractOvine oligodendrocytes (OLGs) undergo biochemical and morphological changes following attachment to polylysine. Autoradiographs of two‐dimensional thin‐layer chromatograms of [14H]Gal‐labeled OLG cultures revealed that attachment of OLGs to a polylysine substratum and their subsequent morphological differentiation is accompanied by an increased synthesis of multiple forms of galactosylceramide, sulfogalactosylceramide, and both sulfogalactosyl‐ and galactosyl‐diglycerides, together with an array of complex sialoglycosphingolipids, predominantly GM2 ganglioside. As previously reported, overall lipid synthesis measured by [14C]acetate incorporation into glycerophosphatides, sphingomyelin, and neutral lipids also increased dramatically for up to 60 days (last time point examined) following OLG‐substratum adhesion, reflecting membrane growth. Attachment was associated with a rapid augmentation in the synthesis of ethanolamine plasmalogen from 12 to 27% within 24 hr to reach a 35% plateau at 30 days and remain constant thereafter. In contrast, the plasmalogen content of phosphatidylcholine remained constant at 3–5%. This rapid increase in lipid synthesis (especially in the ethanolamine plasmalogen content following attachment) closely paralleled increased diacylglycerol (DAG) production and protein kinase C‐dependent phosphorylation of both myelin basic protein and 2′,3′‐cyclic nucleotide phosphohydrolase. Labeling studies indicated that the major source of [3H]arachidonate‐labeled DAG following attachment was from phosphatidylinositol turnover (and to a lesser extent phosphatidylcholine) rather than polyphosphoinositides or plasmalogens. Enhanced lipid synthesis is not only required for the production of membranes in these myelin‐producing cells but is also a source of second messengers required in the posttranslational modification of key myelin and cellular proteins. © 1992 Wiley‐Liss, Inc.
Transcriptional regulation of glial fibrillary acidic protein (GFAP)‐mRNA expression during postnatal development of mouse brain
Authors: Riol H. , Fages C. , Tardy M. 
Published: May 2005

AbstractDuring mouse brain maturation, GFAP‐mRNA undergoes a two‐step developmental expression. It increases between birth and day 15 (period of astrocytic proliferation) and then decreases until day 55 (period of astrocytic morphological differentiation). We have developed an in vitro transcription procedure, as a mean to study the part of transcriptional control in this biphasic expression. After RNA synthesis by endogenous RNA polymerases in nuclei isolated from mouse brain (of 3 to 55 days and 217 days), the relative rates of GFAP‐mRNA transcripts were analysed by hybridization with a specific cDNA probe. As early as 3 days after birth, the rate of GFAP‐mRNA transcripts was maximal, whereas unexpectedly, it showed a significant decrease in mice of 15 days and stayed low until the 55th day. Therefore, a transcriptional control may take place early in mouse brain postnatal development by increasing the transcriptional rate of the GFAP gene in astrocytes, and during the transition from proliferation to differentiation phase of astrocytes (that occurs at the 15th day after birth) by decreasing this rate. However, posttranscriptional events may also occur to modulate the level of the cytoplasmic GFAP‐mRNA. In older mice (217 days), the low rate of GFAP‐mRNA transcripts found is not concordant with the high cytoplasmic level generally observed in gliosis of the aging brain. Our data suggest posttranscriptional events at this age. © 1992 Wiley‐Liss, Inc.
Light and electron microscopic localization of B‐50 (GAP43) in the rat spinal cord during transganglionic degenerative atrophy and regeneration
Authors: Knyihár‐Csillik E. , Csillik B. , Oestreicher A. B. 
Published: May 2005

AbstractCrush or transection of a peripheral nerve is known to induce transganglionic degenerative atrophy (TDA) in the segmentally related, ipsilateral Rolando substance of the spinal cord. When the lost peripheral connectivity is reestablished, the consecutive regenerative synaptoneogenesis results in restoration of the circuitry in the formerly deteriorated upper dorsal horn. Enhanced expression of the growth‐associated protein (GAP43) B‐50 occurs during neuronal differentiation, axon outgrowth, and peripheral nerve regeneration. This study documents changes in immunocytochemical distribution of B‐50 in the regions of the lumbar spinal cord which are segmentally related to the axotomized sciatic nerve.At the light microscopic level, a weak B‐50 immunoreactivity (BIR) is present in the neuropil of the upper dorsal horn of control animals. After unilateral transection and ligation of the sciatic nerve, BIR increased in the ipsilateral upper dorsal horn at 17 days postinjury, but decreased again after 24 days with respect to the contralateral side. Differences between effects of crush and transection were prominent in combined crush‐cut experiments as well (i.e., after unilateral crush and contralateral transection and ligation of the sciatic nerve). Electron microscopic studies show that in the uninjured and injured spinal cord, BIR is detected in axons and axon terminals, but not all are stained. After transection of the sciatic nerve, BIR is found in afflicted primary sensory axon terminals, including those contacting substantia gelatinosa neurons and in axon terminals undergoing glial phagocytosis. The localization of BIR seen after crushing the sciatic nerve is similar. However, at 24 days after crush, BIR is detected also in axonal growth cones.In the ventral horn of control animals, synaptic boutons impinging upon motor neurons exhibited weak BIR. At 17 days after unilateral transection of the sciatic nerve, the pericellular BIR surrounding motor neurons is decreased at the ipsilateral with respect to the contralateral side, whereas 24 days after crush injury it increased considerably.Our results show that peripheral nerve injury inducing TDA also affects BIR distribution in the spinal gray matter. Successful regeneration of the peripheral nerve after crush lesion is associated with enhanced expression of B‐50 in growth cones of sprouting central axons. The neuroplastic response of B‐50 is in line with a function of B‐50 in axonal sprouting and reactive synaptogenesis. © 1992 Wiley‐Liss, Inc.
Insulin‐like growth factor‐I counteracts bFGF‐induced survival of nitric oxide synthase (NOS)‐positive spinal cord neurons after target‐lesion in vivo
Authors: Blottner Dieter , Baumgarten H. G. 
Published: May 2005

AbstractWe have used nitric oxide synthase (NOS) histochemistry as a perikaryal viability marker to trace the retrograde reaction of spinal cord intermediolateral (IML) sympathoadrenal projection (SAP)‐neurons to target‐removal, i.e., selective adrenomedullectomy and local administration of either insulin‐like growth factor‐I (IGF‐I), basic fibroblast growth factor (bFGF) or a combination of both. Counting of NOS‐positive preganglionic spinal cord neurons 4 weeks post surgery indicated that more than 80% of stained neurons were lost from the IML‐cell column. This percentage loss corresponds to the numerical loss of NOS‐stained SAP‐neurons labeled retrogradely with Fast‐blue prior to adrenomedullectomy. Basic FGF‐supplementation at the site of lesion resulted in maintenance of the majority of NOS‐positive IML‐neurons, a finding confirmed by the survival rate of Fast‐blue prelabeled SAP‐neurons. Thus, besides maintenance of the structural integrity of SAP‐neurons, bFGF prevents loss of intracellular NOS‐activity which may reflect unaltered cell metabolism (and function) of these neurons following target‐removal in vivo. By contrast, IGF‐I failed to alter the rate of disappearance of NOS‐staining and labeling index of neurons within the IML‐cell column postlesion, suggesting that IGF‐I is not neurotrophic for SAP‐neurons by itself. Combined treatment with both factors resulted in a more widespread loss of NOS‐stained and Fast‐blue‐prelabeled SAP‐neurons than registered after bFGF‐only treatment. No co‐trophic effect of bFGF and IGF‐I was evident; rather, the pronounced bFGF‐induced rescuing effect was significantly suppressed by exogenous IGF‐I in vivo, supporting the idea that this or another molecule induced by the treatment enhances rather than prevents retrograde degeneration and neuronal death within the adult lesioned IML‐adrenal pathway. © 1992 Wiley‐Liss, Inc.
Ionic dependence of a P2‐purinoceptor mediated depolarization of cultured astrocytes
Authors: Magoski's N. S. , Walz W. 
Published: May 2005

AbstractThe membrane potential of cultured mouse astrocytes was recorded to assess the effects of extracellular adenosine 5′‐triphospate (ATP) and related Hpurines on astrocyte electrophysiology. The purines were applied with or without the presence of barium, which blocks the high resting K+ conductance in astrocytes. The response to ATP alone was a moderate depolarization; however, the response to ATP in the presence of barium was a large, dose dependent depolarization. The ED50 was approximately 10 μM. The effect of adenosine 5′‐diphosphate (ADP) or adenosine 5′‐monophosphate (AMP), in the presence of barium, on membrane potential was less than that of ATP. Adenosine, with or without barium, had no effect on membrane potential; furthermore, adenosine agonists in barium produced no response. The results of applying various ATP analogues indicate that the response is mediated via a P2‐purinoceptor. Ion replacement studies reveal a complicated response to ATP that has serveral components and involves Na+ and K+. These results show that astrocytes respond with ionic changes to very small, physiological concentrations of extracellular ATP. We suggest that ATP plays a role in interactions between neurons/endothelial cells and glial cells. © 1992 Wiley‐Liss, Inc.
Experimental acute traumatic injury of the adult rat spinal cord by a subdural inflatable balloon: Methodology, behavioral analysis, and histopathology
Authors: Martin D. , Schoenen J. , Delrée P. , Gilson V. , Rogister B. , Leprince P. , Stevenaert A. , Moonen Gustave 
Published: May 2005

AbstractWe describe an experimental model to produce closed traumatic injuries to the spinal cord of adult rats. This model uses an inflatable balloon that is introduced in the dorsal subdural space and moved to a location rostral to the laminectomy site. The spinal cord trauma can be graded by varying either the duration of compression or the volume of saline used to inflate the balloon. The locomotor deficit of animals with various degrees of injury has been assessed at increasing delays after trauma. The parameters generating transient or definitive deficits of varying intensity were defined. Some injured animals underwent nuclear magnetic resonance imaging. Detailed histopathological studies demonstrated that the extent of the spinal lesion was significantly correlated with the physical parameters of compression and with the severity of the behavioral deficit. © 1992 Wiley‐Liss, Inc.
Neuronal cells mature faster on polyethyleneimine coated plates than on polylysine coated plates
Authors: Lelong Isabelle H. , Petegnief V. , Rebel G. 
Published: May 2005

AbstractCell morphology, protein/DNA ratio, ganglioside analysis, taurine uptake, and the activity of neurone specific enolase showed that neuronal cells mature faster when grown on polyethyleneimine coated plates compared to cells grown on polylysine coated plates. Our results also show higher protein/DNA ratio and total and neuron specific enolase activities in cells grown in serum supplemented medium, when compared to their counterparts grown in synthetic medium. Moreover, our results show that only some specific markers can be used to determine the early and late events of cell maturation, whereas other markers continuously vary with time. © 1992 Wiley‐Liss, Inc.
Sub‐chronic exposure to opiates in the rat: Effects on brain levels of substance P and calcitonin gene‐related peptide during dependence and withdrawal
Authors: Tiong G. K. L. , Pierce T. L. , Olley J. E. 
Published: May 2005

AbstractSubstance P (SP) and calcitonin gene‐related peptide (CGRP) are putative transmitters in the central and peripheral (sensory) nervous systems. In this study, we examined the effects of dependence on and withdrawal from morphine and methadone on brain SP and CGRP content. Female Long Evans rats (70–100 g) were provided with plain drinking water or solutions containing opiate. No choice of drinking fluid was allowed. The maintenance level of each opiate (0.8 and 0.4 mg/ml for morphine and methadone, respectively) was continued for 4 days. Following an injection with naloxone (10 mg/kg i.p.) or saline, animals were decapitated 0, 20, or 60 min later and regional brain peptide content was measured by specific radioimmunoassays. SP and CGRP content in opiate‐maintained and naive animals were similar following saline injection. However, following naloxone injection in morphine‐maintained animals, SP content was elevated in the hypothalamus and midbrain at 20 min, but by 60 min was no longer distinguishable from basal (0 min) level. CGRP content was increased in the medulla oblongata and followed a comparable time course but, unlike SP, was not altered in the hypothalamus or midbrain. No alterations were observed in methadone‐maintained animals. These results correlated with the peak of the behavioral morphine withdrawal syndrome and were consistent with the comparatively milder abstinence encountered in methadone medication. © 1992 Wiley‐Liss, Inc.