bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differences in the accumulation of lithium in human neuroblastoma and glioma cells in tissue culture
Authors: Saneto Russell P. , Perez‐Polo J. Regino 
Published: January 2005

AbstractA human neuronal and a human glioma line were used to study lithium (Li) transport mechanisms and kinetics of influx. We demonstrated that, unlike the human erythrocyte or clonal neuroblastoma cell SY5Y, the cloned glioma cell line A1B1 had neither a ouabain or phloretin‐sensitive component of Li influx. Furthermore, glioma cells were shown to accumulate significantly more (4 fold) Li and at an apparently faster rate when compared to the neuroblastoma cell, SY5Y, over the same time period. Thus, these two clones may be better in vitro model system for the study of Li transport components native to the human central nervous system as compared to erythrocytes. This study also suggests that glial tissue may preferentially accumulate Li and in this way control the levels of extracellular Li surrounding some neurons.
Growth factor dependence of pheochromocytoma cells in chemically defined medium
Authors: Goodman Rosanne , Herschman H. R. 
Published: January 2005

AbstractWe have previously described the isolation of a clonal pheochromocytoma cell line (PC‐G2) which responds to nerve growth factor (NGF) [Goodman and Herschman, 1978] and epidermal growth factor (EGF) [Goodman et al, 1980] with increased specific activity of tyrosine hydroxylase (TH). This cell line thus can be used for studies of induction of a key enzyme in the biosynthesis of catecholamines using a homogeneous cell population under controlled environmental influences. However, the need for serum in the culture medium used to grow these cells still introduced a lack of total environmental control. Several laboratories have circumvented this problem by growing cells in chemically defined medium. In the present report we demonstrate that with a modification PC‐G2 cells can survive and grow in the chemically defined N3 medium devised by Bottenstein and Sato [1979]. While another pheochromocytoma cell line, PC‐12, was shown to grow in N3 medium without any supplement [Bottenstein et al, 1979], the PC‐G2 cells exhibit an absolute requirement for NGF or EGF in order to grow in this chemically defined medium. As was the case in the induction of TH in serum‐containing medium [Goodman and Herschman, 1978; Goodman et al, 1980], EGF was found to be 100 times more potent than NGF in the support of growth of the PC‐G2 cells. In the present report we demonstrate not only that either of these growth factors will support the growth of the PC‐G2 cells, but also that the relative potency of these two factors for support of the cell growth is similar to their relative potencies in the induction of tyrosine hydroxylase in serum‐containing medium.
Constancy of adult hypothalamic tyrosine hydroxylase after gonadal steroid treatment during development
Authors: Vaccari Andrea , Biassoni Roberto 
Published: January 2005

AbstractTyrosine hydroxylase (TH) was studied in the entire hypothalamus of 60‐day‐old male and female rats, and its activity was similar in both sexes. Administration of estrogen or androgen to male or female pups soon after birth and during development did not affect the kinetic parameters of TH. It is, thus, suggested that sexual dimorphism in the levels and turnover of catecholamines (CA) and their sensitivity to fluctuations in gonadal steroids during development do not depend on corresponding sex‐related or steroid‐sensitive differences in the synthesis of hypothalamic CA.
Human β‐nerve growth factor does not crossreact with antibodies to mouse β‐nerve growth factor in a two‐site radioimmunoassay
Authors: Beck Carol E. , Perez‐Polo J. Regino 
Published: January 2005

AbstractThe nerve growth factor protein (NGF) isolated from mouse submaxillary gland has been shown to be necessary to the development of vertebrate sensory and sympathetic ganglia. Also, wide ranging alterations in the levels of NGF in the peripheral circulation of humans suffering from a variety of neuropathies have been reported. Many of these reports relied on the use of antibodies directed to the mouse β‐NGF subunit for their quantitation of human NGF antigen. We report here on the lack of crossreaction between antibodies directed to mouse β‐NGF and its human counterpart isolated from placenta at term.
Nerve growth factor and cyclic AMP: Opposite effects on neuroblastoma‐substrate adhesion
Authors: Schulze I. , Perez‐Polo J. R. 
Published: January 2005

AbstractIncreased cellular adhesion has been postulated to be an early event required of neuroblasts undergoing neurite extension during differentiation. Nerve growth factor (NGF) induces neurite extension in a variety of cell types of neural crest origin. In the PC12 rat pheochromocytoma cell line, which has been proposed as a model for precursor cells to sympathetic neurons, NGF and dibutyryl cyclic AMP (dBcAMP) promote both neurite extension and an increased rate of cell‐substrate adhesion. Since dBcAMP can substitute for NGF in this enhancement of adhesion rate in the PC12 cell line, cAMP has been suggested as a second messenger for NGF. We have shown that in two nearly diploid adrenergic like human neuroblastoma clones, the KA and SY5Y cell lines, which also extend neurites in response to both NGF and dBcAMP, only NGF enhances cellular adhesion, as defined by an increase in the number of cells prelabeled with 35S‐methionine which attach to culture dishes at a given time. Incubation with monospecific antibodies directed against murine β‐NGF abolishes the NGF effect on adhesion. The NGF effect on human neuroblastoma is specific insofar as NGF does not facilitate adhesion of two glioma lines. Unlike the results obtained for PC12, in both SY5Y and KA lines, 1 mM dBcAMP decreases the rate of adhesion to levels significantly below those of controls. Adhesiveness of neuroblastoma cells treated with both NGF and dBcAMP is intermediate between that of cells treated with either agent alone. While theophylline mimics the dBcAMP effect, sodium butyrate has no such effect. At 22°C, the effect of NGF on neuroblastoma substrate adhesion is observable within 5 minutes and persists for 2 hours; treatment of the KA line with NGF at 37°C for 24 hours results in a more persistent enhancement of cell adhesion. Furthermore, both SY5Y and KA exhibit different morphologies when challenged with NGF, dBcAMP, or sodium butyrate. This study suggests that NGF and cyclic AMP do not share a common mechanism of action, but can in fact interest antagonistically in an adrenergic like neuroblastoma model system. Furthermore, the results suggest that increased cellular adhesiveness may not be an obligatory perequisite for neurite extension by neuroblasts in development.
Biochemical development of the human brain. III. Benzodiazepine receptors, free Y‐aminobutyrate (GABA) and other amino acids
Authors: Brooksbank B. W. L. , Atkinson D. J. , Balázs R. 
Published: January 2005

AbstractBenzodiazepine receptor binding and the concentration of free tissue GABA, glutamate, glutamine, aspartate, and 13 other amino acids were estimated in specimens of cerebral cortex and cerebellum taken from normal foetuses and from perinatal and postnatal infants and adults postmortem.Compared with the ontogenetic increase, previously reported, in [3H]muscimol binding, that of [3H]flunitrazepam binding developed more rapidly in the cerebellum and less rapidly in the cerebral cortex. The concentration of GABA in both brain parts increased with age more rapidly than did that of glutamate decarboxylase activity.The overall pattern of developmental changes in the amino acid concentrations in the human brain showed many similarities with those reported in the brains of experimental animals. The concentration of the amino acids associated with the tricarboxylic acid cycle increased with age. Although the general downward trend in the levels of essential amino acids (with the exception of Met) was also evident in the human cerebral cortex, this was not the case in the cerebellum where the concentrations of most amino acids were relatively low in the foetus whereas the concentrations exceeded the cerebral cortical levels in the adult.
Ventromedial nucleus of the hypothalamus: Convergent excitatory and inhibitory responses to fimbria and stria terminalis stimulation
Authors: Marchand James E. , Defrance Jon F. , Stanley James C. 
Published: January 2005

AbstractField and extracellular unitary potentials were recorded in the ventromedial nucleus of the hypothalamus (VMH) of urethane‐anesthetized rabbits after stimulation of the fimbria and stria terminalis.Stimulation of the lateral portion of the fimbria, which carries fibers from the ventral subiculum of the hippocampal formation, evoked a two‐component response. An early excitatory response, with an average latency of 10 msec, predominated along the lateral margins of the VMH. A later inhibitory potential with an average latency of 15 msec was seen predominantly within the central portions of the VMH. Stimulation of the dorsal component of the stria terminalis produced two similar response patterns: an early excitatory response with an average latency of 16 msec, followed by an inhibitory potential with an average latency of 25 msec. The topographical distribution of these two components of the response was nearly identical to that produced by lateral fimbria stimulation. In contrast, stimulation of the ventral component of the stria terminalis evoked a simple excitatory response with an average latency of 10 msec which was maximal within the core of the VMH.Extracellular unitary recodings showed that the early negativity associated with stimulation of each of these three pathways reflects a monosynaptic excitation of VMH cells and that there was convergence of the three excitatory inputs at the single cell level.
Uptake, release, and binding of taurine in degenerated rat retinas
Authors: Salceda R. , Pasantes‐Morales H. 
Published: January 2005

AbstractHigh‐affinity uptake, potassium‐stimulated release and receptor binding of γ‐aminobutyric acid (GABA) and taurine were studied in retinas of rats treated with monosodium glutamate (MSG) or iodoacetate‐malate (IAM). Such treatments produce a selective damage of the inner retinal layers (MSG) or of the photoreceptor layer (IAM).MSG treatment decreased GABA uptake by more than 60%. Also, the potassium‐stimulated release of this amino acid was markedly diminished (90%) in retinas lesioned by MSG. MSG treatment decreased 3H‐GABA binding by 45%. Uptake, release or binding of GABA were unaffected by IAM‐treatment.Taurine uptake was reduced by a similar degree by both MSG and IAM treatment, 57% and 38% respectively. Potassium‐stimulated release of taurine was unchanged by MSG and 50% reduced by IAM. Both treatments reduced the spontaneous release of endogenous taurine. Binding of taurine to receptors in retinal membranes was practically unaffected by any of the treatments utilized.These results are consistent with a neurotransmitter action of GABA at the inner retinal layers, while they do not support a major role for taurine as a synaptic transmitter in retina.
Effect of transganglionic degenerative atrophy on opiate receptors in the dorsal horn of the spinal cord
Authors: Csillik B. , Kiss J. , Knyihar‐Csillik Elizabeth , Lajtha A. 
Published: January 2005

AbstractWe investigated alterations in opiate‐binding sites in the upper dorsal horn after transection of the related peripheral sensory nerve in rats. The binding of (3H)diprenorphine was measured autoradiographically. The findings indicated a shift of the binding sites, rather than a degenerating disappearance, with a decrease in nerve fibers but an increase in nerve cells. This may be due to latent opiate‐binding sites becoming manifest.
Utilization of ketone bodies and glucose by established neural cell lines
Authors: Roeder Lois M. , Poduslo Shirley E. , Tildon J. Tyson 
Published: January 2005

AbstractThe rates of utilization of [3‐14C]‐acetoacetate, [3‐14C]‐3‐hydroxybutyrate, and [6‐14C]‐glucose were measured in four established cell lines from neuroblastoma of rat (B103) and mouse (N4TG1) and from rat astrocytoma (RGC6) and mouse oligodendroglia (G2620). The rates of incorporation of acetoacetate into lipid were 3–5 times higher than glucose in all cell lines. The incorporation of 3‐hydroxybutyrate was similar to that of glucose. Thin‐layer chromatography of the total lipid extracts showed the same relative rates of use of these substrates for synthesis of various phospholipids and neutral lipids. The rates of incorporation into neutral lipids and phosphatidylcholine were essentially linear for 12 hr; however, that into phosphatidylethanolamine was markedly higher in the second 6 hr interval than in the first. In all cases, the greatest percentage of label (35–50%) appeared in the phosphatidylcholine fraction. The distribution of label from each of the three substrates among the various lipids was similar in the glial cells, but there were marked differeneces in distribution of the two ketone bodies in the neuroblastoma lines. These cells also synthesized lipids that migrated to the same area on the chromatogram as cholesterol esters and free fatty acids. In three of the four cell lines the rates of oxidation were highest for glucose, intermediate for acetoacetate, and lowest for 3‐hydroxybutyrate. The ratios of the rate of incorporation to the rate of oxidation were higher for ketone bodies (3.32 for 3‐hydroxy‐butyrate and 5.29 for acetoacetate) than for glucose (0.41). This indicates that in these cells ketone bodies are directed toward lipid synthesis rather than oxidation, and glucose is preferentially used as an energy source.
[3H]spiperone binding sites in rat primary glial cultures, C6 glioma, and B104 neuroblastoma
Authors: Severson J. A. , de Vellis J. S. , Finch C. E. 
Published: January 2005

AbstractBinding sites for [3H]spiperone were detected on membranes from primary glial cultures from neonatal rat cortex and striatum and from the C6 glioma cells. [3H]Spiperone binding was displacable by d‐butaclamol. However, competition studies suggest that [3H]spiperone binding to primary glial cultures was mainly to serotonergic sites, and binding to the C6 glioma was alpha‐adrenergic. No specific binding was detected to membranes from B104 neuroblastoma cells. Although [3H]spiperone binding to glial sites on whole striatum under generally used conditions is small (about 10%), the striatal glial hyperactivity that is often associated with neuronal degeneration could lead to an overestimation of presumed neuronal binding sites for dopaminergic ligands.
Taurine biosynthesis in frog retina: Effects of light and dark adaptations
Authors: Nishimura Chihiro , Ida Shuji , Kuriyama Kinya 
Published: January 2005

AbstractThe retinal uptake and metabolism of cysteine, a precursor for taurine biosynthesis, were analysed using the bull frog. The [14C] cysteine uptake into isolated retina had some specific properties: It was rather temperature independent, required Na ions, was inhibited by ouabain but not by dinitrophenol, and exhibited saturation kinetics composed of two components. When retinal homogenate was incubated with 12‐30 μM of L‐[U‐14C]cysteine, the accumulation of labeled alanine, cysteine sulfinic acid (CSA), cysteic acid (CA), hypotaurine, and taurine was detected. The metabolic conversions of [14C] cysteine to labeled alanine, hypotaurine, and taurine were linear over 90 minutes. Prolonged light adaptation (3 weeks) induced a significant reduction in the formation of labeled CA, CSA, hypotaurine, and taurine from [14C] cysteine. On the other hand, it was found that in dark‐adapted retinae, the formation of labeled taurine from [14C] cysteine increased significantly in spite of the reduction in the formation of labeled CA. These results indicate that biosynthetic pathways exist for taurine from cysteine in frog retina, and that these metabolic pathways are involved in the regulation of retinal taurine content under continuous visual adaptation.
Nerve growth factor and neural oncology
Authors: Vinores S. A. , Perez‐Polo J. R. 
Published: January 2005

AbstractThe precise role of the nerve growth factor protein (NGF) during the growth and development of the human nervous system is not determined. Although it appears to influence a number of neural functions, its mechanism of action is poorly understood. A number of researchers have proposed that NGF may be involved in several pathological conditions including cancer. It has been shown that NGF is secreted'by certain sarcoma (23), neuroblastoma (113), and glioma (7,102,136) cell lines and can bind to neuroblastoma and metastatic melanoma cell lines (42). Neuroblastoma (136,181) and pheochromocytoma (165) cells in vitro can be induced by NGF to differentiate toward a morphologically “more benign” state and appropriate NGF treatment of rats can reduce the number of chemically induced gliomas and neurinomas (174, 178). NGF can also reduce the growth of intracerebrally inoculated anaplastic glioma cells (172). Anti‐NGF treatment of rats (178) and mice (179) can alter the tumor distribution observed following ethylnitrosourea or benzo(a)pyrene treatment (10). In humans, it has been reported that serum levels of NGF are usually elevated in persons “at risk” for neurofibromatosis (156). The precise nature of the NGF role is not known in these instances. Further understanding of the action of NGF could be of clinical importance.
Cell surface and cytoskeletal antigens in cerebral cell cultures after chloroform‐methanol delipidation
Authors: Yavin E. , Yavin Z. 
Published: January 2005

AbstractFixation and in situ total delipidation of nerve cells in monolayer cultures have been used for immunofluorescence visualization of cellular antigens. Cells grown on poly‐L‐lysine‐coated coverslips are exposed to a chlorofordmethanol (2/1 by vol) solvent mixture for 15 min at −65°C. This step results in the fixation of cells and is accom‐panied by the complete extraction of cellular lipids. About 3.2% of the total 35S‐ methionine‐labeled trichloroacetic acid‐insoluble cellular material is extracted into the organic solvent mixture, demonstrating that aqueous soluble proteins are not signifi‐cantly extracted under these conditions. A total loss of tetanus toxin binding sites, presumably reflecting the removal of polysialogangliosides from the cell surface, is observed. The accessibility of antibodies against tubulin and against intermediate filaments after this treatment has been investigated. Visualization of these cytoskeletal elements by indirect immunofluorescence and by phase microscopy suggests that the removal of cellular lipids does not affect the apparent cytoarchitecture and that extraction with these organic solvents does not interfere with the staining of tubulin and intermediate filaments, the latter being exclusively present in nonneuronal cells. The advantage of this method of cell fixation and lipid extraction for immunofluorescence of cells in monolayer culture is discussed.
Viability, growth, and maturation of fetal brain and spinal cord in the siatic nerve of adult rat
Authors: Bernstein J. J. 
Published: January 2005

AbstractThe feasibility for growth, maturation, and differentiation of fetal nervous system implanted into adult mammalian peripheral nervous system was studied. Thirtyfive adult rats had the epineurium of the sciatic nerve crushed, perineurium minced, and fetal rat cortex or spinal cord implanted. Rats were utilized 7, 14, and 21 days, and 1, 2, 3, and 4 months later. A 1‐mm cube of cortex or a 1‐mm segment of spinal cord of 11‐, 12‐, or 15‐day gestation fetuses was placed into the epineurium. Age‐matched controls (7 DPI (days postimplantation) control for E15 implant was a 1‐day pup, 21 days' gestation) were utilized for comparison (two per time group). Five animals had sciatic crush and perineurial mince only, and the gait and toe‐spreading response were observed over 4 months. All implanted animals walked normally at 30 days. All implants were successful and survived the duration of the experiment. Cortical implants produced prominent bulges in the epineurium (21 days–4 months). Maximal neuronal and neurolgial cell division was observed at 7–21 days, decreased at 30 days, and stopped by 60 days. Most implanted cortical neurons had mature nuclei and immature dendritic patterns (apolar), and rarely had mature dendritic patterns. Neuroglia were abundant. The younger the cortical implant, the larger the cell mass produced (E11 > E15). The spinal cord implants survived, were viable, contained mainly neuroglia, and grew minimally. Host Schwann cells and nerve fibers were found in and around the implants. These data show that adult peripheral nervous system can act as an environment for growth and viability of fetal CNS implants.
Ultrastructural changes in the sensomotor cortex of the rabbit after complete 30‐min brain ischemia
Authors: Pluta R. , Gajkowska B. 
Published: January 2005

AbstractExperiments were performed on rabbits in which complete 30‐min brain ischemia was induced. Electron‐microscopic studies revealed higher susceptibility to ischemia of the motor cortex than the sensory cortex, which was manifested by a higher number of damaged nerve cells in the former than in the latter. Ultrastructural abnormalities of motor cortex neurons, including the presence of numerous vesicular structures in the cell nuclei, swelling of mitochondria, and an increase in the number of intracytoplasmic fibrillary structures appeared 3 h after blood recirculation and became more intensive after 6 h.
Differential sensitivity of estrogen target tissues: Implications for estrogen regulation of serum luteinizing hormone
Authors: Kelner K. L. , Peck E. J. 
Published: January 2005

AbstractIn the rat, it is generally accepted that the primary site of estrogen's stimulatory (positive) effects on serum LH is the preoptic area‐anterior hypothalamus (POA/AH). In contrast, the primary site of estrogen's inhibitory (negative) effects on serum LH levels has not been conclusively identified. There is evidence to suggest both a medial basal hypothalamic (MBH) and an anterior pituitary site of action. The present studies utilized a unique characteristic of these estrogen effects to investigate their putative loci. Extensive dose‐response curves of estrogen's induction of positive and negative feedback indicated that the negative feedback response was activated at a lower concentration of serum estradiol than the positive feedback response. The differential sensitivities of these two responses suggested that the tissues mediating them might also be differentially sensitive to estradiol. In a previous paper, we showed that receptor translocation is an index of estrogen sensitivity. We measured receptor translocation in response to a series of estradiol doses in the POA/AH, the MBH, and the pituitary. Dose‐response curves for estrogen's effect on receptor translocation showed that the pituitary receptor translocation mechanism is activated at significantly lower levels of serum estradiol than that of either the POA/AH or the MBH. These results are consistent with the POA/AH as a site of estrogen's positive feedback effects. In addition, they suggest that negative feedback in the rat may be mediated via estrogen's action at the anterior pituitary. Estrogen's negative feedback effect on serum LH occurs at a serum level of estrogen at which no receptor is translocated in the MBH. Therefore, the pituitary, which does possess nuclear receptors at these estradiol dose levels, is more likely to be the primary mediator of estrogen's negative feedback effects. In another experiment, pituitary, but not hypothalamic, receptor was translocated to the nuclear fraction with an injection of 100 μg clomiphere (Clomid). Under these conditions serum LH is depressed, thus strengthening the hypothesis that, in the rat, estrogen action on the pituitary can cause suppression of serum LH independently of the hormone's action in the hypothalamus.