bluuebunny/crossref_metadata_2025_split huggingface dataset:
β‐Oxidation of [1‐14C]palmitic acid by mouse astrocytes in primary culture: Effects of agents implicated in the encephalopathy of Reye's syndrome
Authors: Murphy M. G. , Jollimore C. , Crocker J. F. S. , Her H. 
Published: January 2005

Abstractβ‐Oxidation of [1‐14C]palmitic acid was examined in homogenates of astrocytes cultured from neonatal mouse brain. Under optimal reaction conditions (≤50 μg protein, 10 min at 37°C), oxidation increased as a function of palmitate concentration (15 μM to 2 mM) and reached a maximum rate of 1.98 ± 0.29 nmol/min/mg protein (mean ± SEM) at 0.2 mM substrate. Eadie‐Hofstee analysis of data from four experiments yielded apparent values for Vmax of 1.87 nmol/min/mg protein, and for Km, 35–40 μM. There were no dramatic changes in the oxidation rate in cells between 10 and 36 days in culture. During the 10‐min assays, less than 0.05% of the radioactivity was converted to 14CO2 by the astrocytes; water‐soluble products accounted for 1–2% of the total substrate added. Studies with KCN indicated that 60–70% of the total activity occurred in the mitochondria.We have been studying the structural and functional changes associated with the cerebral encephalopathy of Reye's syndrome (RS). Three‐week‐old astrocytes exposed to serum from RS children for the final 7 days of culture exhibited minor mitochondrial pleomorphism and had increased numbers of other intracellular organelles. Examination of the effects of agents implicated in RS indicated that oxidation of [1‐14C]palmitate was not altered by Na+ salicylate (1–3 mM), but was inhibited by the industrial surfactant, Toximul MP‐8 (≥10 μg/ml), 4‐pentenoic acid (≥01 μM), or with 4 days' exposure to ammonia (10 mM). The latter treatment also resulted in an increase in protein synthesis, cell volume, and malondialdehyde formation. These results suggest that some of the “toxins” implicated in RS inhibit fattyacid oxidation in the astrocytes and produce other lipid‐related abnormalitities that could be related to encephalopathy. © Wiley‐Liss, Inc.
The neural cell adhesion molecule (NCAM) heparin binding domain binds to cell surface heparan sulfate proteoglycans
Authors: Kallapur S. G. , Akeson R. A. 
Published: January 2005

AbstractThe neural cell adhesion molecule (NCAM) has been strongly implicated in several aspects of neural development. NCAM mediated adhesion has been proposed to involve a homophilic interaction between NCAMs on adjacent cells. The heparin binding domain (HBD) is an amino acid sequence within NCAM and has been shown to be involved in NCAM mediated adhesion but the relationship of this domain to NCAM segments mediating homophilic adhesion has not been defined. In the present study, a synthetic peptide corresponding to the HBD has been used as a substrate to determine its role in NCAM mediated adhesion. A neural cell line expressing NCAM (B35) and its derived clone which does not express NCAM (B35 clone 3) adhered similarly to plates coated with HBD peptide. A polyclonal antiserum to NCAM inhibited B35 cell‐HBD peptide adhesion by only 10%, a value not statistically different from inhibition caused by preimmune serum. Both these experiments suggested no direct NCAM‐HBD interactions. To test whether the HBD peptide bound to cell surface heparan sulfate proteoglycans (HSPG), HSPG synthesis was inhibited using β‐D‐xyloside. After treatment, B35 cell adhesion to the HBD peptide, but not to control substrates, was significantly decreased. B35 cell adhesion to the HBD peptide could be inhibited by 10−7 M heparin but not chondroitin sulfate. Preincubation of the substrate (HBD peptide) with heparin caused dramatic reduction of B35 cell‐HBD peptide adhesion whereas preincubation of B35 cells with heparin caused only modest reductions in cell‐HBD adhesion. Furthermore, inhibition of HSPG sulfation with sodium chlorate also decreased the adhesion of B35 cells to the HBD peptide. These results strongly suggest that, within the assay system, the NCAM HBD does not participate in homophilic interactions but binds to cell surface heparan sulfate proteoglycan. This interaction potentially represents an important mechanism of NCAM adhesion and further supports the view that NCAM has multiple structurally independent binding sites. © 1992 Wiley‐Liss, Inc.
Interaction of AChE with Lens culinaris agglutinin reveals differences in glycosylation of molecular forms in sarcoplasmic reticulum membrane subfractions
Authors: Campoy F. J. , Cabezas‐Herrera J. , Vidal C. J. 
Published: January 2005

AbstractFractionation of muscle microsomes rich in sarcoplasmic reticulum (SR) by isopicnic centrifugation yielded three types of membranes. Heavy (HM), intermediate (IM), and light membranes (LM), with isopicnic points of 38, 33, and 25% w/w sucrose, were rich in terminal cisternae/triads, longitudinal SR, and T‐tubules, respectively. All membrane subfractions displayed acetylcholinesterase (AChE) activity. About 60, 80, and 50% of total AChE in HM, IM, and LM was extracted with a Tris‐saline‐Triton buffer. AChE molecular forms of 4.5 S (G1), 10.5 S (G4), and 16 S (A12) were found in all membranes but their relative proportion varied among the several membranes. Asymmetric and tetrameric forms were partly sedimented with Lens culinaris agglutinin (LCA), but most of the monomeric AChE failed to interact with the lectin. However, some of the monomers, exclusively found in LM, reacted with LCA. The data suggest that monomeric AChE is classified in rough endoplasmic reticulum. A subset is destined to SR, a second one converted into oligomeric forms, and a third one is associated to external membrane after passing through the Golgi system. © 1992 Wiley‐Liss, Inc.
In search of the central respiratory neurons: II. Electrophysiologic studies of medullary fetal cells inherently sensitive to CO2 and low pH
Authors: Rigatto H. , Fitzgerald S. C. , Willis M. A. , Yu C. 
Published: January 2005

AbstractAlthough extensively pursued, the central respiratory neurons have remained elusive. We departed from the more conventional physiologic and morphologic methods of system and tissue examination and cultured dissociated fetal rat cells (Fitzgerald et al., J Neurosci Res 33:579–589, 1992) from the area of the nucleus ambiguus and the nucleus tractus solitarius located within the 2 mm rostral to the obex. Pacemaker‐like cells, with a regular single or bursting activity, studied at 3–5 weeks of age, responded to very small pulses of CO2 (50 ms) and low pH with an increase in spike frequency and a decrease in spike amplitude. Other irregularly beating or silent cells did not respond or else required very large pulses (>200 ms) to do so. The pacemaker cells also responded to hypoxia induced by administration of sodium hydrosulfite with an increase in spike frequency and amplitude; high oxygen (>600 torr) and adenosine produced a decrease in electrical activity. Most of these cells were multipolar after staining with antibodies to neuron‐specific enolase (NSE) and Fragment C of tetanus toxin. They did not stain for choline acetyltransferase (ChAT). The results suggest that these cultured cells, expressing a phenotype inherently responsive to CO2 and low pH, have the characteristics of central respiratory chemoreceptors, and may be involved in the generation of the respiratory rhythm. © 1992 Wiley‐Liss, Inc.
Lack of effect of interleukins 1α and 1β, during in vitro perifusion, on anterior pituitary release of adrenocorticotropic hormone and β endorphin in the male rat
Authors: Parsadaniantz S. Mélik , Lenoir V. , Terlain B. , Kerdelhué B. 
Published: January 2005

AbstractIt has been demonstrated that interleukin 1 (IL1) injection provokes a great variety of biological effects, notably an activation of the corticotropic axis, increasing plasma adrenocorticotropic hormone (ACTH) and corticosterone. However, the primary site of action of IL1 is still controversial. In the present study, we first verified the in vivo capability of human interleukins 1α (hIL1α) and 1β (hIL1β) to release ACTH and β endorphin (β EP) in the normal male rat, before investigating, through an anterior pituitary (AP) perifusion system, the hIL1α and hIL1β effects on basal and corticotropin‐releasing factor (CRF)‐induced ACTH and β EP secretions. This system enabled the examination of a dynamic profile of hormones secretion, avoiding the possibility of feedback mechanisms, as is the case with the use of regular but very often longtime incubations.The results showed that in a perifusion system, with a short duration treatment (below 2 hr) compatible with the kinetics of action observed in vivo, basal and CRF‐induced ACTH and β EP release were not modified in the presence of a broad range of concentrations (from 10−12 to 10−9 M) of hIL1α or hIL1β. Taken together, these results clearly show that in an in vitro situation close to physiological conditions, the primary site of action of hIL1α and hIL1β on ACTH and β EP release is not located at the AP level in the male rat. © 1993 Wiley‐Liss, Inc.
Regulation of phospholipase D activity in a human oligodendroglioma cell line (HOG)
Authors: Dawson G. , Dawson S. A. , Post G. R. 
Published: January 2005

AbstractOligodendroglial cells express many specific proteins, such as myelin basic protein (MBP), which are physiologically phosphorylated by protein kinase C (PKC). Diacylglycerols are physiological activators of PKC and can be liberated from phospholipids by the direct receptor‐mediated activation of phospholipase C (PL‐C) or indirectly via the activation of phospholipase D (PL‐D). In a well‐characterized human oligodendroglioma (HOG) cell line, PL‐C (measured by release of [3H]inositol phosphates) and PL‐D (formation of [3H]myristoylated or palmitoylated phosphatidylethanol) were activated by both carbachol (blocked by pirenzepine, suggesting an M1 receptor) and histamine (H1 receptor) but not glutamate, bradykinin, or phenylephrine. PL‐C stimulation by carbachol or histamine was completely inhibited by short‐term treatment (<30 min) with phorbol ester (TPA), a PKC activator. In contrast, PL‐D activation by either carbachol or histamine was stimulated in additive fashion by TPA, suggesting at least two distinct mechanisms for PL‐D activation. Down regulation of PKC by prolonged (24 hr) treatment with TPA reversed the inhibitory effects of TPA on PL‐C and the stimulatory effects on PL‐D. However, the PKC inhibitors H‐7 and galactosylsphingosine did not inhibit the TPA‐mediated stimulation of PLD while the less‐specific PKC inhibitor, staurosporine, was only partially inhibitory. Preexposure of cells to carbachol, greatly reduced both PL‐C and PL‐D activation by carbachol, suggesting homologous desensitization. Time‐course studies indicated that PL‐D activation (10 sec or less) was at least as fast as PL‐C activation, and the affinity of carbachol and histamine for the receptor coupled to either phospholipase (EC50 = 5–10 μM) was about the same. We conclude that in this oligodendroglioma, and by inference in oligodendroglial cells, the receptor‐coupled PL‐D pathway, is at least as important as the PL‐C pathway as a source of DAG and that its relationship to PKC is complex. © 1993 Wiley‐Liss, Inc.
Plasminogen activator inhibitor 1, the primary regulator of fibrinolysis, in normal human cerebrospinal fluid
Authors: Rao Jasti S. , Chen M. , Festoff Barry W. 
Published: January 2005

AbstractThe occurrence of type‐1 plasminogen activator inhibitor (PAI‐1) in human cerebrospinal fluid (CSF) has not previously been reported. As a member of the serpin superfamily of serine protease inhibitors and an acute phase response component, PAI‐1 has powerful potential roles in nervous system homeostasis. We have detected this serpin antigen using a polyclonal anti‐PAI‐1 antibody in normal human CSF. In Western blotting, PAI‐1 in several CSF samples appears as a two‐band antigen of Mr = 54 and 35 kDa, presumably the intact and proteolytic fragment, respectively. In vitro complex formation studies confirm that the 54 kDa form of PAI‐1 interacts with 125I‐urokinase after activation with SDS, but the 35 kDa form does not. Quantification of total PAI‐1 antigen in 18 normal human CSF samples by ELISA reveals a mean value of 1.0 ± 0.07 (SEM) μg/dL, indicating that a relatively low concentration of the inhibitor occurs in normal human CSF. This information should now allow comparison of PAI‐1 levels and activity in various neurologic disorders. © 1993 Wiley‐Liss, Inc.
Microglial conditioned medium promotes survival and development of cultured mesencephalic neurons from embryonic rat brain
Authors: Nagata K. , Takei N. , Nakajima K. , Saito H. , Kohsaka Shinichi 
Published: January 2005

AbstractWe previously reported that microglial conditioned medium (Mic‐CM) has a neurotrophic effect on cultured rat neocortical neurons [Nakajima et al. (1989): Biomed Res 10:411–423]. In order to investigate the interaction between microglia and neurons in more detail, we determined the effects of Mic‐CM on the primary cultured mesencephalic neurons from 16‐day embryonic rats. The addition of Mic‐CM to the culture medium significantly enhanced the survivability of neurons and promoted neurite extension in a low cell‐density culture condition. In a high cell‐density culture condition, Mic‐CM markedly increased dopamine uptake, which was quantified by assessing the specific [3H]dopamine uptake, and also increased the dopamine content of cultured cells. Furthermore, the number of mesencephalic dopaminergic neurons, which was determined by quantitative analysis of tyrosine hydroxylase (TH)‐immunoreactive cells, increased significantly in the presence of Mic‐CM. These results suggest that Mic‐CM enhances survival or maturation of TH‐positive neurons present in cultures of the embryonic mesencephalon and that these neurotrophic effects may be due to a diffusible factor(s) from microglia. © 1993 Wiley‐Liss, Inc.
Detection of choline‐acetyltransferase activity in lymphocytes
Authors: Rinner I. , Schauenstein K. 
Published: January 2005

AbstractThe cholinergic system takes part in the immune‐neuroendocrine interation. Lymphocytes have been found to express muscarinic and nicotinic cholinergic receptors, as well as acetylcholine‐esterase on their surface, and cholinergic agents modulate immune functions in vitro and in vivo. In the present study we provide evidence that purified organ resident and circulating lymphocytes, as well as various lymphoid cell lines derived from different species, exhibit choline‐acetyltransferase activity and, therefore, have the potential to produce the neurotransmitter acetylcholine. © 1993 Wiley‐Liss, Inc.
110/140 laminin‐binding protein immunoreactivity in spinal dorsal root ganglia: A capsaicin‐insensitive reduction induced by constriction injury of the sciatic nerve in rats
Authors: Ren K. , Kibbey M. C. , Kleinman H. K. , Ruda M. A. 
Published: January 2005

AbstractThe distribution of 110/140 laminin‐binding protein (110/140 LBP) in the spinal dorsal root ganglia (DRG) and its regulation by partial constriction of the sciatic nerve was studied in adult rats. The cross‐sectional area of neurons with 110/140 LBP‐immunoreactivity (−I) showed an approximately normal frequency distribution. The 110/140 LBP‐I was observed in neuronal cell bodies exclusive of the nucleus. Following sciatic nerve constriction, the 110/140 LBP‐I was downregulated in the ipsilateral L4‐5 DRG. DRG neurons with a cross‐sectional area ≥ 1600 μm2 were preferentially affected. Neonatal capsaicin‐treatment, a procedure that selectively destroys a subpopulation of DRG neurons with fine unmyelinated axons, had no effect on the reduction of 110/140 LBP in the DRG induced by sciatic nerve constriction. Western immunoblot analysis confirmed a reduction of 110/140 LBP on the side ipsilateral to the constriction. These results demonstrate a LBP within primary sensory neurons and its suppression by peripheral nerve injury. The data support a role for LBP in the adult nervous system.© 1993 WiIey‐Liss, Inc.This article is a US Government work and, as such, is in the public domain in the Unitcd States oC America.
Evidence for hemi‐gap junctional channels in isolated horizontal cells of the skate retina
Authors: Malchow R. P. , Qian H. , Ripps H. 
Published: January 2005

AbstractProlonged depolarization of isolated, voltageclamped skate retinal horizontal cells produces an outward current that exhibits a late onset and develops slowly with time. This current, which we refer to as the Q‐current, is associated with an increase in membrane conductance, and is present when other voltage‐gated conductances have been pharmacologically blocked. The reversal potential for the Q‐current, obtained using tail current analysis, was close to 0 mV. The magnitude of the current was greatly reduced by superfusion with 25 mM acetate, and by 4 mM cobalt chloride, 2 mM 1‐octanol, and a saturated solution of the general anesthetic halothane. In addition, the low‐molecular weight fluorescent dye Lucifer yellow, applied extracellularly, entered the cells during activation of the Q‐current, whereas a 3 kD dextran‐fluorescein complex did not cross the cell membrane. The effects of divalent cations, the nonspecific nature of the ionic current suggested by its reversal potential, the entry of Lucifer yellow, and the ability of acetate, halothane, cobalt, and octanol to block the current lead us to hypothesize that the Q‐current results from the opening of hemi‐gap junctional channels that mediate electrical coupling between skate horizontal cells. © 1993 Wiley‐Liss, Inc.
Dye‐induced photolesion in the mammalian retina: Glial and neuronal reactions
Authors: Picaud S. , Peichl L. , Franceschini N. 
Published: January 2005

AbstractIrradiation in the presence of a dye applied to the extracellular space is known to produce degenerative features in irradiated neurones and fibers. In the present study, we confirmed the potential use of this procedure as a lesion technique by showing the removal of degenerating elements as part of the glial reaction to the lesion. The dye Rose Bengal was applied to the vitreous body of a rat eye and a T‐shaped irradiation pattern was projected onto the retina within the absorption band of the dye. Degenerative features were restricted to the irradiated area, which could be readily identified from its shape. Retinae examined after various survival times showed that macrophages invaded the damaged area within 1 day, and that mitotic activity of reactive glial cells subsequently occurred in the vicinity of the wound. Both cell types were identified by their structural features. Macrophages were also revealed by a staining technique using the dye Nile Red, whereas reactive glial cells were immunolabeled with an antibody directed against the glial fibrillary acidic protein. Reactive glial cells helped the macrophages to gradually remove injured cells and damaged processes. Their main task, however, appeared to be in scar formation, since their processes seemed to suture the lips of the wound together and restore the limiting membrane at the inner retina. After 2 months' survival time, the parent ganglion cells of most disrupted axon bundles had retrogradely degenerated, but regenerating ganglion cell axons were also observed. These results provide some new data about healing processes in the retina. They demonstrate that the dyeinduced photolesion technique can be used to either remove or axotomize selected neurones in neural networks which have been made optically accessible. c 1993 Wiley‐Liss, Inc. © 1993 Wiley‐Liss, Inc.
Amphiphilic and hydrophilic forms of acetyl‐ and butyrylcholinesterase in human brain
Authors: Sáez‐Valero J. , Tornel P. L. , Muñoz‐Delgado E. , Vidal C. J. 
Published: January 2005

AbstractHuman brain acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) were sequentially extracted, first with a Tris‐saline buffer (S1) and then with 1% (w/v) Triton X‐100 (S2). About 20 and 30% of the AChE and BuChE activities were recovered in S1 and most of the remaining enzymes in S2. Main molecular forms of about 10.5 S and 12.0 S, G4 forms of AChE and BuChE, and smaller amounts of 4.5 S and 5.5 S forms, G1 species of AChE and BuChE, were measured in S1. Application of Triton X‐114 phase partitioning and affinity chromatography on phenyl‐agarose to S1 revealed that 25% of the AChE and none of the BuChE molecules displayed amphiphilic properties. Analysis of the enzyme activity retained by the phenyl‐agarose showed that G1 AChE constituted the bulk of the amphiphilic molecules released without detergent. Main G4 forms of AChE and BuChE were found in the S2 extract. Eighty and 45% of the AChE and BuChE activities in S2 were measured in the detergent‐rich phase by Triton X‐114 phase partitioning. Thus, most of the AChE and about half of the BuChE molecules in S2 displayed amphiphilic properties. The main peak of BuChE, a 12.0 S form in gradients made with Triton X‐100, splits into two peaks of 9.5 S and 12.5 S in Brij 96‐containing gradients. This suggests that hydrophilic G4 BuChE forms are predominant in S1 and that hydrophilic and amphiphilic isoforms coexist in S2. © 1993 Wiley‐Liss, Inc.
Expression of three nonallelic genes coding calmodulin exhibits similar localization on the central nervous system of adult rats
Authors: Ikeshima H. , Yuasa S. , Matsuo K. , Kawamura K. , Hata J. , Takano T. 
Published: January 2005

AbstractBy Northern blot analysis with the digoxigenin‐labeled antisense RNA probes of the noncoding regions, the transcripts of three calmodulin (CaM) genes, CaMI, CaMII, and CaMIII, were separately detected in 12 different tissues of adult Wistar albino rats, without any cross‐hybridization. The mRNAs of all three CaM genes were abundant in the central nervous system (CNS) as well as in the testis, although ubiquitous expression was detected at low levels in the other tissues. There were subtle but significant differences in the tissue‐specific distribution of the three CaM gene RNAs. By in situ hybridization, strong hybridization of the three CaM gene probes was observed in common in large projection neurons of the CNS: the hippocampal pyramidal cells, the cerebellar Purkinje cells, and the large neurons of the cerebral neocortex, the pyriform cortex, the mesencephalon, the pons, and the spinal cord. The expression of the three CaM genes was at lower levels in small interneurons of the CNS. These profiles of expression were almost the same among the three CaM genes. Thus, all three CaM genes were coordinately expressed in neurons of the adult rat CNS. Certain reulatory mechanisms of the three CaM genes seemed to mediate similar tissue‐ and cell type‐specific expression in the CNS. © 1993 Wiley‐Liss, Inc.