bluuebunny/crossref_metadata_2025_split huggingface dataset:
Maternal ethanol consumption and synaptic membrane glycoproteins in offspring
Authors: Noronha Antonio B. , Druse Mary J. 
Published: January 2005

AbstractThe present study was undertaken to assess the influences of chronic maternal ethanol consumption, prior to and during gestation, on the development of synaptic plasma membranes (SPMs) and on the synthesis of SPM glycoproteins in offspring. Comparisons were made between animals whose mothers were pair‐fed a control or 6.6% (v/v) ethanol liquid diet in which protein accounted for either 18% (original) (C & E) or 21% (revised) (*C & *E) of the calories. In addition, groups of pups that were either cross‐fostered (*C & *E) with chow‐fed surrogate mothers or reverse cross‐fostered (offspring of chow‐fed mothers with *C & *E mothers) were examined. Ethanol and matched (same dietary group) control pups had comparable brain and body weights, brain protein content, and yield of SPM proteins during the 10–24 day age period examined. However, the yield of SPM proteins from ethanol and control offspring of and/or reared by the three groups of rat mothers that received the *E and *C liquid diets was greater than that of the offspring of rats that were fed the original diets. This suggests that the original diets were not nutritionally adequate for pregnant rats. Despite the fact that the content of SPM proteins was comparable in ethanol and matched control pups, the offspring of ethanol‐treated rats had an abnormal distribution of [3H]‐or [14C]‐fucose‐derived radioactivity among SPM glycoproteins. The SPM abnormalities were most severe in the non‐cross‐fostered offspring of E rats. No SPM glycoprotein abnormalities were found in the reverse cross‐fostered group. The results of the present study demonstrate that chronic maternal ethanol consumption prior to parturition has a severe effect on the synthesis of SPM glycoproteins in developing offspring without affecting the content of SPMs per se. It also demonstrates the importance of optimizing the composition of liquid diets used to feed pregnant rats.
Nerve growth factor: Subunit interactions in the mouse submaxillary gland 7S complex
Authors: Silverman Robert E. , Bradshaw Ralph A. 
Published: January 2005

AbstractSedimentation velocity analyses of the isolated subunits of mouse 7S nerve growth factor (NGF) and their binary complexes have been performed. The 2.5S (β) form of NGF binds 2 α subunits independent of the presence of γ subunits. Two γ subunits are also complexed by 2.5S NGF; however, this interaction is dependent on the presence of a carboxyl terminal arginine residue on the β polypeptide chain. The partial loss of this residue in 2.5S NGF preparations results in a ternary complex(es) with a reduced sedimentation coefficient(s). The two binary complexes formed (α2‐β and β‐γ2) show markedly different pH stability profiles. The α and γ subunits do not form a demonstrable complex, but apparently can interact in the ternary complex to render it more stable than the sum of the α‐β and β‐γ interactions.
Characteristics of the association of nerve growth factor with primary cultures of rat sympathetic neurons
Authors: Hawrot Edward 
Published: January 2005

AbstractLong‐term primary cultures of rat sympathetic neurons require NGF for survival and development. The kinetics of the interaction of 125I‐NGF with sympathetic neuron cultures suggests the presence of diffusional barriers preventing a determination of true dissociation and association rate constants. Although the observed rate constants do not accurately reflect the microscopic interaction of NGF with receptor, the ratio of the observed rate constants does provide a good estimate of the KD. This value (1 × 10−9M) agrees with earlier steady state measurements of the KD. The association of 125I‐NGF with neuronal cultures is temperature‐dependent with internalization and retrograde transport occurring at 37°C. The retrograde transport of 125I‐NGF in compartmentalized neuronal cultures is concentration dependent and saturates at about 100 ng/ml (4 × 10−9M). The amount of 125I‐NGF accumulated by retrograde transport appears to be increased subsequent to a period of NGF‐starvation. The increase in uptake does not appear to be due to an increase in NGF receptor number since the number of binding sites is not greatly increased upon NGF starvation.
Comparative features of spinal neuronotrophic factors in fluids collected in vitro and in vivo
Authors: Manthorpe Marston , Longo Frank M. , Varon Silvio 
Published: January 2005

AbstractSurvival in monolayer culture of 4‐day (stage 23) chick embryo lumbar spinal cord neurons can be regulated by two opposing activities. One, spinal neuronotrophic activity, promotes neuronal survival; and the other, spinal neuronotoxic activity, eliminates the neurons from the culture even when the trophic support is present at an optimal concentration. Quantitative microbioassays for each activity are presented and used to measure the relative amounts of each agent within different sources including glial, muscle, and spinal cord cell‐conditioned media and fluid collected from peripheral and central nervous tissue lesions. Although both activities were present in all of the sources tested, their concentrations in the wound fluids were orders of magnitude greater than in the conditioned media. The fluid‐derived trophic activities were inactivated by heat and trypsin and nondialyzable, whereas all of the conditioned media‐derived trophic activities were heat‐ and trypsin‐resistant and dialyzable.
Cultures of zona ependyma cells of goldfish brain: An immunological study of the synthesis and release of ependymins
Authors: Majocha R. E. , Schmidt R. , Shashoua V. E. 
Published: January 2005

AbstractTwo proteins (ependymins β and γ) localized within specific cells in the zona ependyma of goldfish brain were identified in previous studies in our laboratory as extracellular factors whose metabolism was highly increased by the acquisition of new patterns of behavior. Methods for growing zona ependyma cells in culture were developed to determine if cells within this tissue could synthesize and release the ependymins into their extracellular environment. Dissociated cells from zona ependyma were grown as primary monolayer cultures on polylysine‐coated slides. The cultures survived for at least 4–5 weeks, forming an intricate network of interconnecting processes. These contained many cell types, several of which retained their in vivo immunohistochemical properties. Specific populations of cells staining with antisera to nerve growth factor, glial fibrillary acidic protein, and ependymins β and γ were present. Radioimmunossay, immunoelectrophoresis data, and labeling experiments indicate that cells within the cultures can synthesize the ependymins de novo and release them into their extracellular environment. These results are consistent with the hypothesis that the ependymins might function as extracellular factors which mediate the behaviorally induced plasticity of the goldfish CNS. In this respect they resemble other “protein factors” which stimulate the growth and morphological differentiation of nervous system cultures.
Failure of nerve growth factor to enhance wound healing in the hamster
Authors: Leitzel Kim , Cano Cheryl , Marks James , Lipton Allan 
Published: January 2005

AbstractWe have investigated the effect of topically applied high molecular weight nerve growth factor (HMW‐NGF) and 7S nerve growth factor (7S NGF) on healing of full‐thickness skin wounds in the Syrian hamster. Our results indicate that HMW‐NGF and 7S NGF have no significant influence on the rate of wound contraction or on the time to complete healing in this animal model.
Regulation of the proliferation of embryonic chick leptomeningeal cells in vitro by both contact inhibition and co‐culture with CNS neurons
Authors: Partlow Lester M. , Hanson Glen R. , Iversen Patrick L. 
Published: January 2005

AbstractCultures of leptomeningeal cells (LMCs) isolated from the pia‐arachnoid membrane of 10‐day chick embryos were studied in order to elucidate the mechanisms which regulate the proliferation of these embryonic nonneuronal cells. Thymidine incorporation was quantified in LMC cultures of varying density and in co‐cultures containing both LMCs and neurons. The following results were obtained. First, proliferation of LMCs was very sensitive to contact inhibition. Second, proliferation was also inhibited by co‐culture of leptomeningeal cells with neurons isolated from either the cerebral hemispheres or optic lobes. Third, co‐culture with sympathetic neurons isolated from the peripheral nervous system did not inhibit LMC proliferation; thus, the inhibition resulting from co‐culture with neurons exhibits some regional specificity. Fourth, proliferation of the leptomeningeal cells was inhibited by addition of the sonicate of either cerebral neurons or LMCs but stimulated by addition of the sonicate of sympathetic neurons.The effect of addition of varying numbers of either intact or sonicated cerebral neurons on thymidine incorporation by cerebral glial cells was also examined. Addition of intact cerebral neurons stimulated cerebral glial proliferation at all concentrations. In contrast, addition of sonicate of cerebral neurons stimulated proliferation at low concentrations but inhibited it at high concentrations. Since addition of intact cerebral neurons inhibits the proliferation of leptomeningeal cells under the same conditions which stimulate the proliferation of cerebral glial cells, these neurons might play a complex role in orchestrating the proliferation of nonneuronal cells during development of the brain.
Catecholamines in rat brain following postnatal undernutrition and nutritional rehabilitation
Authors: Wiggins Richard C. , Fuller Gregory N. , Seifert William E. , Butler Ian J. , Gottesfeld Zehava 
Published: January 2005

AbstractNorepinephrine and dopamine were examined in 19 discrete brain areas from the telencephalon, diencephalon, and mesencephalon of nutritionally rehabilitated adult rats following postnatal undernutrition from birth through 21 days of age. Following rehabilitation, catecholamine levels were not significantly different from control values in any of the areas examined. Catecholamine concentrations in young, undernourished rats are generally elevated (either from stress or from nutritional insufficiency). Data presented here show that whichever case is true, the early effect of undernourishment is transient and that normal values are restored by nutritional rehabilitation.
Muscarinic cholinergic binding in chick embryo retino‐tectal system: Effects of corticosterone
Authors: Gremo Fulvia , Vernadakis Antonia 
Published: January 2005

AbstractMuscarinic binding sites were measured using the radioligand [3H]quinuclidinyl benzilate (QNB) in the retina and tectum of 11‐day‐old chick embryos, after intracerebral administration of 0.02 μg of corticosterone at 8 days of incubation. This age was chosen because the hormone preferentially accumulates in retinas at 8 days of development. Hormone treatment significantly affected the affinity of 3H‐QNB‐binding sites in retinas and slightly affected the affinity in treated tecta, whereas the number of binding sites remained unchanged. The specific binding was determined with either atropine or unlabeled QNB. Scatchard plot analysis of specific 3H‐QNB binding revealed the presence of nonsaturable binding at high 3H‐QNB concentrations (6‐11 nM) in the treated retinas, but not in controls. It can be concluded from these data that the hormone has a primary effect on retinal cells during early growth in the chick embryo. The possibility that the hormone delays maturation of specific populations of retinal cells is considered in the discussion.
Interaction of manganese with NB41A neuroblastoma adenylate cyclase
Authors: Reiss D. S. , Sapirstein V. S. 
Published: January 2005

AbstractIn vitro assay of the adenylate cyclase of NB41A neuroblastoma cells in the presence of increasing concentrations of MnCI2 suggested that the enzyme is modulated by both high‐ and low‐affinity sites for manganese. MnCI2 in a concentration of 1 μM significantly stimulated adenylate cyclase activity, but increasing the concentration of manganese to 3 μM or 10 μM had no further effect. Raising MnCI2 to 0.1 or 1 mM, however, further stimulated enzyme activity. In addition to differences in affinity for manganese, the two classes of binding sites may be distinguished by differences in their interaction with other agents that affect adenylate cyclase activity. Millimolar manganese and magnesium appeared to compete for a common site on the enzyme and the effect of manganese in this range and the effect of guanyl nucleotide were synergistic. In contrast, the stimulation of activity by micromolar manganese appeared to be additive to the effects of either increasing magnesium or the addition of guanyl nucleotide to the assay media. Comparison of the substrate dependency of the reaction measured in the presence and absence of manganese suggests that the stimulation of adenylate cyclase activity involves increases in both the apparent Vmax of the reaction and the affinity for ATP. The results raise the possibility that the interaction of Mn2+ may play a role in the modulation of adenylate cyclase in vivo.
Long‐term effect of electroshock treatment on the entry of calcium into the cerebroventricular fluid in the rat
Authors: Barkai Amiram I. 
Published: January 2005

AbstractThe rate of appearance (Ra) of calcium (Ca) in the cerebroventricular compartment of urethane‐anesthesized rats was determined by two methods: one is measurement of isotope dilution during ventricular‐cisternal perfusion with artificial cerebrospinal fluid (CSF) containing 45Ca, the other is estimation of the rate of entry of 45Ca from plasma after rapid injection of tracer 45CaCl2 intravenously. Electroshock treatment (EST) for 3 successive days resulted in a marked increase in the rate of entry of calcium from blood to CSF. The effect of EST on the permeability of the blood‐CSF bamer to Ca could be observed even 24 hr after the generalized seizure induced by electroshock has terminated.
Acetylation of polyamines in mouse brain: Subcellular and regional distribution
Authors: Ortiz J. G. , Giacobini E. , Schmidt‐Glenewinkel T. 
Published: January 2005

AbstractThe acetylation of putrescine, cadaverine, spermidine, and spermine was examined in different subcellular fractions and regions of the mouse brain. Acetylation activity was confined to nuclear and microsomal fractions, which can acetylate all of these compounds. These fractions catalyze the formation of N8 but not N1‐acetylspermidine. For the nuclear fraction the Km for putrescine was 3.5 mM; for cadaverine, 4.0 mM; for spermidine, 1.0 mM; and for spermine, 2.5 mM. The Vmax obtained were (pmol/mg protein/10 min): putrescine, 424; cadaverine, 705; spermidine, 239; and spermine, 467.The acetylation of spermidine was highest in the olfactory bulb and cerebellum. Putrescine and cadaverine acetylation were high in these areas, as well as in the midbrain. Spermine acetylation was rather uniform in all areas examined, except in the brain stem (pons‐medulla) where enzyme activity was very low.
Ion dependency of uptake and release of GABA and (RS)‐nipecotic acid studied in cultured mouse brain cortex neurons
Authors: Larsson O. M. , Drejer J. , Hertz L. , Schousboe A. 
Published: January 2005

AbstractThe influence of sodium ions on GABA uptake into neurons cultured from cerebral cortex was investigated at sodium concentrations ranging from 16 to 151 mM. Sodium did not affect the Km for GABA uptake but the uptake rates as a function of the sodium concentration was sigmoid at all GABA concentrations studied (1‐200 μM). Hill plots of these curves exhibited straight lines with slopes of 1.7‐2.1, suggesting that the coupling ratio between sodium and GABA is at least 2. (RS)‐Nipecotic acid, a GABA analogue, was transported with high affinity (Km 8.0 ± 2.1 μM) like GABA, but the Vmax for nipecotic acid was lower than found for GABA (0.664 ± 2 0.035 versus 0.955 ± 2 0.059 nmol × min−1 × mg−1), suggesting a microheterogeneity of the GABA transport sites. Neurons loaded with the respective vitiated compounds exhibited a pronounced K+‐stimulated, calcium‐dependent release of both GABA and nipecotic acid indicating that these cultured cells have developed functionally active GABA‐ergic synapses.
Cultured neonatal rat oligodendrocytes elaborate myelin membrane in the absence of neurons
Authors: Bradel Edward J. , Prince F. P. 
Published: January 2005

AbstractWe have utilized transmission electron microscopy to study oligodendrocyte‐enriched cell cultures established from dissociated neonatal rat cerebra by the method of McCarthy and de Vellis [1980]. Cells were examined after 14 and 26 days in vitro. The overall morphology of the cells from cultures at both time periods was similar and consistent with previous reports of light (immature) oligodendrocyte fine structure. The cells contained an eccentrically located nucleus, prominent Golgi regions, numerous free ribosomes, and microtubules. Large numbers of processes with varying diameter were also observed. There was some indication of cytoplasmic maturation from the younger to the older cultures. The most important feature of the 26‐day cultures was the large quantity of intercellular membranes which were shown to be continuous with oligodendrocyte processes. There membranes often exhibited the appearance of “loose myelin” and were therefore not normally compacted. Layers of membrane with the morphologic apperance of compact myelin were observed on an occasional oligodendrocyte perikaryon or process. This finding necessitates a reevaluation of the widely held theory that oligodendrocytes are not able to elaborate myelin in the absence of neurons.
Sprouting inducing activity of human sera: Low capacity in sera from patients with cranial polyneuropathy
Authors: Aviel Aaharon , Schwartz Michal 
Published: January 2005

AbstractCranial idiopathic acute peripheral facial nerve paralysis (Bell palsy) has been used as a model disease in the present study mainly to investigate trophic capacity of serum components. The ability to induce sprouting from chick embryo dorsal root ganglia was used as the bioassay for trophic activity. Sera from normal patients induce neuritic outgrowth from dorsal root ganglia of chick embryo in the absence of any exogenous factor. Sprouting, to a very limited extent or none, has been induced by 80% of the sera derived from the Bell palsy patients. Further analysis of the biochemical nature of the reduced activity has revealed that in sera of Bell palsy patients the substances that are fractionated within the Ig fraction are responsible for the reduced capacity to induce sprouting without loss of supportive molecules.
The active site of lysosomal sphingomyelinase: Evidence for the involvement of hydrophobic and ionic groups
Authors: Callahan J. W. , Jones C. S. , Davidson D. J. , Shankaran P. 
Published: January 2005

AbstractThe natural substrate for sphingomyelinase contains hydrophobic and polar moieties. In this study, we have employed pH rate studies and examined hydrophobic compounds and phosphorylated esters for their effect on sphingomyelinase activity in an attempt to determine some of the kinetic properties of this enzyme. Sphingomyelinase, purified from human placentae, undergoes noncompetitive inhibition by octylglucoside and Nonidet P‐40, two nonionic detergents containing terminal octyl groups. The effect of these detergents at the hydrophobic binding site is somewhat different from that of Triton X‐100, which contains an isooctyl terminal group, and this may serve to identify a structural basis for the effects.Sphingomyelinase activity is also modulated by several nucleotides. Inhibition by 5′‐adenosine monophosphate (5′‐AMP) is also noncompetitive. Other nucleotide monophosphates (such as 5′‐uridine monophosphate (5′‐UMP), 5′‐cytidine monophosphate (5′‐CMP), 2′‐adenosine monophosphate (2′‐AMP), and 3′‐adenosine monophosphate (3′‐AMP) and phosphorylated intermediates (such as phosphorylcholine, phosphorylethanolamine and hexose phosphates) have a lower inhibitory effect. The data suggest that the inhibition by 5′‐AMP involves the combined effect of the phosphate group and the purine ring, structural requirements which may also be satisfied by bis(4‐methylumbelliferyl)phosphate, a synthetic enzyme substrate.Studies of pH rate indicate that the maximal velocity for the hydrolysis of sphingomyelin is independent of pH over the range 3.5–6.2 while the Km value shows a pH dependence. The Km value is lowest from pH 4.0–5.2 and rises at pH values outside this range. The log Vmax/Km and pKm relationships, when plotted as a function of pH, have been used to identify the dissociation constants for the binding of sphingomyelin by the enzyme. These occur at pK values of 4.1 and 5.5. The activity of sphingomyelinase is also reduced when the enzyme is photooxidized in the presence of methylene blue or rose bengal and carbamylated by diethylpyrocarbonate (DEPC).These results are interpreted to show that (1). the ezyme contains a hydrophobic binding site which involves linear aliphatic moieties containing at least eight carbon atoms; (2) two ionic groups are involved in formation of the enzyme substrate complex, one of which is presumed to be the carboxylate group of aspartate or glutamate (represented by pK 4.1) and the second may be the protonated imidazolium group of histidine (represeted by pK 5.5); and 3) since the maximal velocity shows no pH dependence, the interactions involving the hydrophobic and ionic groups affect only the binding of te substrate to the enzyme and formation of the enzyme‐substrate complex.
Measurement of prostaglandin biosynthetic capacity in discrete areas of the rabbit hippocampal formation
Authors: Lysz T. W. , Needleman P. , Ferrendelli J. A. 
Published: January 2005

AbstractAssay conditions sensitive enough to measure prostaglandin (PG) biosynthetic capacity in discrete brain areas have been developed. Serial sections of the rabbit hippocampal formation were dissected from the brain, frozen, and 16 m̈m sections were cut and freeze dried. The assay was performed with 40—200 m̈g dry weight of tissue in a 30 m̈l incubation volume containing high specific activity arachidonic acid. The whole hippocampal formation slice or its subdivisions (subiculum, dentate gyrus, and hippocampus) when assayed individually demonstrated the ability to produce approximately 30—50 pmol/mg dry weight PGF2α, PGE2, and lesser amounts of PGD2 (in a ratio of 1:0.8:0.3). A modest yet significant increase in PGE2 production was measured in the dentate gyrus when compared to PGE2 formation in the subiculum or hippocampus. An intact PGE2 isomerase was confirmed in the hippocampal formation slice by incubations with PGH2 endoperoxide. These results demonstrate that quantitative histochemical techniques can be used to measure PG metabolism in microscopic regions of brain.