bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of nerve growth factor producing cells on anaplastic glioma and pheochromocytoma clones: Involvement of other factors
Authors: Vinores Stanley A. , Koestner Adalbert 
Published: January 2005

AbstractWhen the NGF‐secreting C‐6 rat glioma cells were intracerebrally injected with F98 rat anaplastic glioma cells into rats syngeneic for the F98 cells, an increased mean survival time was observed for rats developing tumors compared with those injected with only anaplastic glioma cells. Thirty percent of the rats injected with both cell types showed no signs of tumor at 90 days. Pretreatment of the anaplastic glioma cells with conditioned medium of C‐6 cells did not duplicate these results unless the C‐6 cells were pretreated with 17β‐estradiol, which appears to induce secretion of an adhesion factor as well as NGF. These rats survived even longer and 33% were free of tumors as 90 days. Histological examination of tumors of the nonsurviving rats revealed that they were basically well differentiated with only small anaplastic areas remaining. Both NGF and conditioned medium from C‐6 and another NGF‐secreting line, S‐180 mouse sarcoma, induce process formation in F98 cells and in PC12 pheochromocytoma cells, but the processes that appear following NGF exposure are morphologically different from those induced by conditioned medium. Conditioned‐medium‐treated cells also have a flatter appearance. In F98 cells, NGF takes longer to induce processes than does conditioned medium. The NGF‐induced effects observed in both cells are neurtralized by anti‐NGF IgG, but those induced by conditioned media are not. Nerve growth factor (NGF) induced increased adhesiveness in F98 rat anaplastic glioma and PC12 rat pheochromocytoma cells. Conditioned media are not. Nerve growth factor induced increased adhesive‐ and PC12 cells. Anti‐NGF IgG did not influence this effect on F98 cells and only partially neutralized the effect on PC12 cells, indicating that other factors may be operative in this system. Conditioned medium collected from C‐6 cells pretreated with 17β‐estradiol induced the highest degree of adhesiveness observed in both F98 and PC12 cells, and this action was unaffected by anti‐NGF IgG in either case. Conditioned media from other cell lines, a variety of selected proteins, and dBcAMP did not induce increased adhesiveness. The factor responsible for this effect is nondialyzable, heat‐sensitive, and ammoniumsulfate‐precipitable, and its secretion appears to be stimulated by 17β‐estradiol.
Effect of CDP‐choline on the biosynthesis of phospholipids in brain regions during hypoxic treatment
Authors: Alberghina M. , Viola M. , Serra I. , Mistretta A. , Giuffrida A. M. 
Published: January 2005

AbstractAcute administration of CDP‐choline (i.p. 100 mg/Kg b.w.), 10 min before the intraventricular injection of labeled precursors, [2‐3H]glycerol and [1‐14C]‐palmitate, was able to correct the impairment caused by hypoxic treatment of lipid metabolism in some brain regions, ie, cerebral hemispheres, cerebellum, and brainstem.After CDP‐choline treatment, an increase of the specific radioactivity of total lipids and of phospholipids was observed in mitochondria purified from the three above‐mentioned brain regions of the hypoxic animals, while no effect on the other subcellular fractions was found. CDP‐choline had a stimulating effect particularly on the incorporation of both precursors into mitochondrial PC, PE, and polyglycerophosphatides isolated from the three brain regions examined.The results obtained show that the action of CDP‐choline in restoring lipid metabolism was more pronounced in brain mitochondria, which, among subcellular fractions, were the most affected by the hypoxic treatment.
Isolation and partial amino acid sequence analysis of nerve growth factor from the guinea pig prostate
Authors: Rubin Jeffrey S. , Bradshaw Ralph A. 
Published: January 2005

AbstractNerve growth factor (NGF) has been purified from the guinea pig prostate using a modification of the Bocchini‐Angeletti method for isolating 2.5S NGF from mouse submaxillary glands. As with the mouse preparation, guinea pig prostate NGF appears to migrate as a high molecular weight entity at physiological pH. Following dissociation, NGF, active in neurite proliferation assays and similar in size to mouse 2.5S NGF, can be isolated by chromatography on a column of carboxymethyl‐cellulose at pH 4.8. Based on gel filtration, SDS‐polyacrylamide gel analysis, and amino‐terminal sequence studies, this material consists of two, noncovalently linked, identical polypeptide chains each with a molecular weight of about 13,000. The amino‐terminal third of the polypeptide chain is at least 90% identical to the corresponding region of the murine molecule, confirming the homology of the guinea pig prostate protein to NGFs obtained from different tissues in other species. However, in contrast to the mouse preparation, the putative high molecular weight form of guinea pig NGF does not contain a subunit with arginine esteropeptidase activity. Although there is an abundance of this enzymatic activity in the homogenate, it does not appear to be associated with the fractions containing NGF. This apparent difference in the mouse and guinea pig material is of interest because the mouse γ subunit, possessing the arginine esteropeptidase activity, has been alleged to participate in the processing of a precursor of the β NGF polypeptide chain.
Sequestration requirements for the degradation of 125I‐labeled β nerve growth factor bound to embryonic sensory neurons
Authors: Stach Robert W. , Wagner Barbara J. 
Published: January 2005

AbstractNerve growth factor interacts with responsive cells by binding to cell surface membrane receptors. There are two different receptors on both embryonic sensory and sympathetic neurons, a high‐affinity (type I) receptor and a lower‐affinity (type II) receptor. Sequestration, which we have defined as bound nerve growth factor that becomes inaccessible to the external milieu with time, occurs through the type I receptor on both sensory and sympathetic neurons. We describe here a process subsequent to sequestration involving internalization and degradation of bound nerve growth factor and showing that bound nerve growth factor is not degraded under the following conditions: (1) low temperature, ie 4°C; (2) when a large excess of unlabeled nerve growth factor is added concomitantly with the labeled nerve growth factor and the temperature is raised from 4°C to 37°C; (3) when metabolic inhibitors sodium fluoride and dinitrophenol are added concomitantly with the labeled nerve growth factor and the temperature is raised from 4° to 37°C. On the other hand, conditions that allow bound nerve growth factor to be degraded are the following: (1) incubation of the sensory nerve cells at low temperature (ie, 4°C) only in the presence of labeled nerve growth factor, then raising the temperature to 37°C; (2) when sodium fluoride and dinitrophenol are added when the temperature is raised to 37°C; (3) when excess unlabeled nerve growth factor is added when the temperature is raised to 37°C.These studies are consistent with the idea that nerve growth factor has to bind to the cells in order to be degraded; however, binding is not sufficient for degradation to occur. Second, the bound nerve growth factor must be sequestered in order to be degraded. Third, the process of internalization of the bound nerve growth factor, unlike sequestration, is not an energy‐dependent process. Thus, it seems reasonable to suggest the following steps for the interaction of nerve growth factor with responsive cells: binding to a cell surface membrane receptor, followed by sequestration of the bound nerve growth factor, and finally, internalization of the sequestered nerve growth factor.
Nerve growth factors in chick tissues
Authors: Ebendal Ted , Hedlund Kjell‐Olof , Norrgren Gunilla 
Published: January 2005

AbstractBioassays of factors promoting nerve growth in embryonic ganglia are described. Chick embryo extract evokes fiber outgrowth in both sympathetic and ciliary ganglia explanted into a collagen gel. The response is not suppressed by antibodies directed against mouse nerve growth factor (NGF). Chick embryo extract also supported survival of neurons in both intact and dissociated ganglia. In addition to these non‐NGF activities, preliminary evidence is presented for the release of a NGF‐like factor from cultured iris of the adult chick.
Stimulation of chick neuroblast proliferation in culture by brain extracts
Authors: Barakat I. , Sensenbrenner M. , Labourdette G. 
Published: January 2005

AbstractChick neuroblasts from 6‐day‐old embryos were grown on a collagen substrate in minimum Eagle's medium supplemented with 5% horse serum. We found that [3H]thymidine incorporation in these cultures decreased drastically from day 2 to day 3 after seeding. Addition of brain extract from 8‐day‐old chick embryos (CBe8) to the nutrient medium after 24 hours of culture elicited a very important stimulation of [3H]thymidine incorporation. Extracts of brains from adult animals were much less effective. It was shown that the increase of tritiated‐thymidine incorporation reflected proliferation of neuroblasts in the culture, at least between day 2 and 4. The activity of the brain extracts was destroyed by trypsin treatment, which suggests that the factor responsible for the stimulation of the proliferation is a polypeptide. The CBe8 and the brain extract of adult chicken (CBa) were fractionated by gel filtration. An active fraction was eluted at a volume indicating an apparent molecular weight of roughly 70,000. At that stage of the study results suggest that a polypeptide (tentatively called neuroblast proliferation factor, NPF) present in the embryonic chick brain extract, is a proliferation factor for chick neuroblasts in primary culture.
Growth from regenerating goldfish retinal cultures in the absence of serum or hormonal supplements: Tissue extract effects
Authors: Johnson James E. , Turner James E. 
Published: January 2005

AbstractThe minimal requirements for the regeneration of optic nerve fibers in vitro were established in a serum‐free retinal explant preparation. This serum‐free preparation was developed as a prerequisite for testing the growth‐promoting activity of tissue extracts prepared from the primary target of regenerating fibers. Explants taken from goldfish retinas 14 days after a prior optic nerve crush were capable of long‐term survival and regenerated neurite outgrowth without serum or hormonal supplements. Serum‐free conditions for explant outgrowth required only a basic Leibovitz (L‐15) media containing 0.6% methyl cellulose (MC). Explants were also capable of neurite outgrowth in L‐15 media alone when culture dishes were preplated with MC. MC treatment permitted both the regeneration of neurites in serum‐free L‐15 and a significant increase in the rate and extent of neurite outgrowth when combined with 10% fetal calf serum (FCS). Explants grown in L‐15 with both MC and FCS produced a 2.5‐fold increase in the length of neurite outgrowth over MC alone and a 1.5‐fold increase in the length of neurite outgrowth over FCS alone. MC activity which permitted minimal serum‐free regeneration and optimal serum supplemented regeneration was determined to be substrate related. Retinas were dissociated to determine if ganglion cells, like the intact explant, were capable of survival and neurite regeneration in serum‐free conditions. These cells survived and extended long neurites when grown in L‐15 with FCS or with FCS and MC, but they did not survive in serum‐free L‐15 with MC.The minimal serum‐free conditions for explant for explant survival and neurite regeneration were used as a model system to test the growth‐promoting activity of crude tissue extracts prepared from the goldfish brain. Extracts prepared from the primary target region, the optic tectum, stimulated a significant 2.5‐fold increase in the length of regenerating neurites. The optic tectal extract (OTex) stimulated outgrowth with significantly high specific activity when compared with extracts of identical protein concentrations prepared from the cerebellum (Cex). At a minimal protein concentration of 150 μg/ml, the OTex stimulated a 1.5‐fold increase in neurite outgrowth above Cex.These results indicated that a serum‐free culture preparation had been established for optic nerve regeneration. This culture system has proven to be an extremely sensitive bioassay model without the masking effect of a serum supplement. Serum‐free cultures may be used in further studies to determine the role neurotrophic factors may play in a widely used model of successful central nervous system (CNS) regeneration.
Separate factors produced by the CNS of the snail Helisoma stimulate neurite outgrowth and choline metabolism in cultured neurons
Authors: Barker David L. , Wong Richard G. , Kater Stanley B. 
Published: January 2005

AbstractNeurons from the snail Helisoma require a brain‐derived factor(s) for neurite outgrowth in both organ and isolated cell culture. This factor is released from the CNS of Helisoma when brains are incubated in defined medium, producing a conditioned medium (CM). In addition to its growth‐promoting activity, CM also enhances total uptake of 3H‐choline and the incorporation of 3H‐choline into specific metabolites: acetylcholine, phosphorycholine and lipid.This choline metabolism‐enhancing factor(s) is distinct and separable from neurite growth‐promoting factor: 1. Over 95% of neurite growth‐promoting activity can be removed from CM by adsorption to a polylysine surface while there is no loss of choline metabolism‐enhancing activity. 2. When central ganglia were treated with anisomycin, a potent inhibitor of molluscan protein synthesis, the choline metabolism‐enhancing activity was completely absent from the resulting CM, while the growth promoting activity was reduced by only 35%. These results suggest that the Helisoma CNS produces a variety of trophic factors that are involved in regulating the interaction between neuronal growth and metabolism.
Astrocytes and lymphocytes: Intercellular communication by growth factors
Authors: Fontana A. 
Published: January 2005

AbstractA proliferation and hypertrophy of astrocytes and their processes are characteristic in inflammatory diseases of the brain. The mechanisms leading to this astrocytic reaction and the functional meaning of this response are unknown. This article reviews the evidence that by their ability to respond to lymphocyte‐derived growth factors and to secrete immunoregulatory molecules, astrocytes may participate in immune responses in the central nervous system.
Epidermal growth factor binding and mitogenic activity on purified populations of cells from the central nervous system
Authors: Simpson D. L. , Morrison R. , de Vellis J. , Herschman H. R. 
Published: January 2005

AbstractBinding of 125I‐epidermal growth factor (EGF) to purified populations of rat astrocytes, oligodendrocytes, and neurons was measured. Astrocytes bound 40,000–100,000 EGF molecules per cell, while oligodendrocytes bound only 6,000–10,000 EGF molecules per cell. In contrast, neurons had little or no capacity to bind 125I‐EGF. EGF alone was able to stimulate incorporation of tritiated thymidine fivefold in purified astrocyte cultures incubated in serum‐free medium. When EGF was added to the previously described chemically defined medium for astrocytes, incorporation of tritiated thymidine in purified astrocytes was equivalent to that observed in medium containing 10% fetal calf serum. Addition of EGF to this chemically defined medium also doubled the proliferative capability of the medium for cultured astrocytes. EGF was maximally effective in stimulating 3H‐thymidine incorporation at concentrations between 1–10 ng/ml.
Stimulation of proliferation and maturation of rat astroblasts in serum‐free culture by an astroglial growth factor
Authors: Pettmann B. , Weibel M. , Daune G. , Sensenbrenner M. , Labourdette G. 
Published: January 2005

AbstractAstroblasts from brain hemispheres of newborn rats were cultivated for 5 days in a complete medium containing 10% fetal calf serum. Cultures were then grown in basal medium in absence of serum. In these conditions, after 15 days only a few cells remained. When the basal culture medium was supplemented with insulin and transferrin (IT medium) the number of the remaining cells was twice higher. However, it was still lower than that found in the 5‐day cultures before serum was removed. Thus the IT medium does not allow a good survival of the cells. Addition to the medium of an astroglial growth factor (AGF) from bovine brain soluble extract led to a tenfold increase of the cell number compared to cultures maintained in the basal medium alone. Effects of the factor on cell survival and on proliferation were examined independently. It was found that the factor did not greatly increase the survival of the cells but that it stimulated the proliferation. Addition of the growth factor to the IT medium elicited an increase of the levels of S‐100 protein and of the activity of glutamine synthetase, two proteins which are specific to astroglial cells in the central nervous system.These results indicate that the astroglial brain factor allows growth and maturation of the rat astroblasts maintained in serum‐free medium.
Purification, characterization, and biological properties of the eye‐derived growth factor from retina: Analogies with brain‐derived growth factor
Authors: Barritault Denis , Plouët Jean , Courty José , Courtois Yves 
Published: January 2005

AbstractSeveral ocular tissues contain a polypeptide growth factor(s) (eye‐derived growth factor(s) or EDGF) that stimulates the proliferation of a large variety of cells from different tissues or species. Partial purification of EDGF from adult bovine retina was accomplished by acid precipitation, blue Ultrogel chromatography, and high‐pressure liquid chromatography. EDGF has an isoelectrical point at pH 4.5 ± 0.5 and an apparent molecular weight of 17,500 ± 3,500 measured by high‐pressure liquid chromatography. On the basis of these data as well as its biological properties EDGF is different from other known growth factors. The specific activity of highly purified EDGF is 1,000‐fold greater than that of a 20,000g supernatant of a crude retinal extract. At this stage of purification, EDGF stimulates replicative DNA synthesis and cell proliferation of bovine epithelium lens cells at a concentration of 14 ng/ml of culture medium and for these cells is as efficient as purified brain fibroblast growth factor.The same purification steps were applied to crude bovine brain extracts. Growth factor activity was recovered exactly as for EDGF with slightly smaller apparent molecular weight 14,000 ± 3,500, suggesting a great similarity between the two tissues as a source of growth factors. A purification of about 2,500‐fold was obtained and cell proliferation stimulated at a concentration of 100 ng/ml. Interestingly an inhibitory activity not retained on blue Ultrogel was recovered from both preparations.
DNA‐polymerases in neuron and glial cells of developing and aging mouse brain
Authors: Shrivastaw Keshaw Prasad , Philippe Michel , Chevaillier Philippe 
Published: January 2005

AbstractDNA‐polymerases α and β were studied in neuron and glial cells of mouse during developing and aging brain. Maximum activity of α‐enzyme was found to be prenatal, though a very low but significant level could be detected in aging brain. Furthermore, this pattern was found to be dependent upon cell types that shift in peak activity just before birth in glial cells in contrast to neurons. DNA‐polymerase‐β remained high throughout the period studied though a second peak of activity was also observzd at day 30 in both cell types, suggesting a possible role in DNA‐replication in addition to DNA‐repair. It was found that β‐enzyme from glial cells behaves differently than the same enzyme from neurons.
Ornithine as a precursor of glutamate and GABA: Uptake and metabolism by neuronal and glial enriched cellular material
Authors: Shank Richard P. , LeM. Campbell Graham 
Published: January 2005

AbstractThe uptake and metabolism of (U‐14C) L‐omithine by several cellular preparations was examined and compared to corresponding data for glutamine and α‐ketoglutarate. Five fractions were obtained from the cerebellum of 10‐to 14‐day‐old mice; two fractions were enriched in astrocyte cell bodies, whereas one was comprised primarily of granule cell bodies, and another was enriched in nerve terminals. Metabolic studies were also conducted on two synaptosomal preparations prepared from rat cerebral tissue.The uptake of ornithine by the cerebellar fractions was mediated by one or two saturable transport systems with apparent Km values between 50 and 200 μM. Uptake inhibition experiments indicated that ornithine is transported primarily, if not exclusively, by the basic amino acid carrier(s), and that glutamine is transported in part by this carrier. Ornithine was metabolized to proline, glutamate, and to a lesser extent aspartate, glutamine and GABA. Under the conditions of our experiments, the cell bodies metabolized ornithine somewhat more readily than did the nerve terminal enriched fraction obtained from the mouse cerebellum. Our data indicate that the conversion of ornithine to GABA occurs predominantly, if not exclusively, via the pathway involving glutamate rather than putrescine. In comparison to data for glutamine and α‐ketoglutarate, the metabolism of omithine to glutamate was slow.Although the results of our study are consistent with the hypothesis that ornithine serves as a metabolic precursor of the neurotransmitter pools of glutamate and GABA, our data do not support a major role for omithine in this capacity. Based on a comparison of the availability of omithine, glutamine and α‐ketoglutarate, and the rates at which they are each transported into synaptosomes and metabolized therein to glutamate and GABA, our data suggest that glutamine and α‐ketoglutarate are used more extensively to replenish these transmitter pools.
The effect of centrally administered neuropeptides on the development of stress‐induced gastric ulcers in rats
Authors: Hernandez Daniel E. , Nemeroff Charles B. , Orlando Roy C. , Prange Arthur J. 
Published: January 2005

AbstractNeurotensin (NT) and bombesin, which are heterogeneously distributed in both brain and gastrointestinal tissue of several mammalian species, inhibit the formation of stress‐induced gastric ulcers in rats. Many other endogeneous neuropeptides have also been reported to be present in brain and gastrointestinal tissue. present study was conducted to evaluate the effect of some of these peptides the development of cold‐restraint stress (CRS)‐induced gastric ulcers in rats. addition, the effect of thyrotropin‐releasing hormone (TRH), which antagonizes many of the CNS effects of NT, was investigated to determine whether tripeptide antagonizes the cytoprotective effect of NT in this CRS model.All peptides were initially administered intracisternally (ic) in doses equimolar to 30 μg NT. As previously reported, NT (30 μg, ic) completely prevented development of gastric ulcers in rats exposed to three hours of CRS. Bombesin, β‐endorphin, substance P, and somatostatin also exhibited cytoprotective activity, Several other peptides studied in the CRS model exerted no significant effects the development of gastric ulcers; these included cholecystokinin octapeptide, gastrin, leu‐enkephalin, met‐enkephalin, and bradykinin. Two peptides, vasculative intestinal polypeptide and TRH, significantly increased the severity of ulcerations.The cytoprotective effect of NT was dose dependent. In contrast, lower doses of β‐endorphin, substance P, and somatostatin were cytoprotective whereas higher doses were not. Finally, concomitant ic injections of TRH antagonized the cytoprotective effects of NT and bombesin, but not that of,β‐endorphin. The present results suggest that certain brain peptides may participate in modulating the gastric mucosal barrier, thereby increasing or decreasing its vulnerability to stress‐induced lesions.