bluuebunny/crossref_metadata_2025_split huggingface dataset:
Essential fatty acid deficiency: A suggestion concerning experimental design
Authors: Levine S. , Ivasauskas E. Y. , Sowinski R. , Kikkawa Y. 
Published: January 2005

AbstractIn experiments on essential fatty acid deficiency, various strategems have been used to balance the deficient and control groups for all nutrients except essential fatty acids. We suggest the use of a single fat‐free diet for both groups, with essential fatty acids administered parenterally to the control (nondeficient) group once each week.
Antagonistic effects of taurine and 4‐aminopyridine on guinea pig ileum
Authors: Arzate M. E. , Ponce H. , Pasantes‐Morales Herminia 
Published: January 2005

AbstractThe effects of 4‐aminopyridine (4‐AP) and of taurine on the guinea pig ileum were examined. Four‐AP increases the basal activity from 1.3 to 6.45 cm2/min. This effect is atropine‐sensitive and calcium‐dependent. Taurine counteracts the effects of 4‐AP on muscle contracture in a concentration‐dependent manner. In muscles preincubated with 20 mM taurine, the effect of 4‐AP decreased about 65%. Taurine added at the time of maximal effect of 4‐AP reduced the muscle contracture induced by the drug to the basal levels. Glycine and β‐alanine did not influence the contracture induced by 4‐AP, whereas 25 mM γ‐aminobutyric acid (GABA) reduced it by 30%. Taurine reduced the basal muscle activity by 50% but did not affect the contracture induced by exogenously applied acetylcholine.
Ultrastructure of fetal spinal cord and cortex implants into adult rat spinal cord
Authors: Bernstein J. J. , Patel U. , Kelemen M. , Jefferson M. , Turtil S. 
Published: January 2005

AbstractThe ultrastructure of cortex and spinal cord from 11‐, 12‐, and 15‐day‐old fetuses implanted into the spinal cord of adult rats was studied over 3 months. Under deep Chloropent anesthesia, a 0.5 × 1.0‐mm square of fetal cortex or a 1.0‐mm segment of fetal spinal cord was implanted subpially between the left dorsal column and the dorsal horn of 70 adult rats. Implants grew toward gray matter, usually interfacing with the host at the isthmus between the horns of the spinal cord. However, implants were observed that occupied the entire left dorsal and ventral horns of the left half of the host spinal cord. Implants had concentric zones: A central zone with basal lamina lined joined channels and subjacent neuroglia; a zone of differentiating implant nervous system; a zone with basal lamina lined implant with overlying pial cells on the dorsal and lateral surfaces of the implant; a zone that interfaced with the host with overlapping neuropil on the lateral and ventral surfaces of the implant. Neuron types were typical for cortical or spinal implants. Implants survived for 3 months and reached stages of neuronal and neuroglial maturation similar to controls. Both fetal spinal cord and brain were successful as implants, had delayed differentiation, and formed complex neuropils. The zone of overlapping interface of the donor and host is an anatomical indication of physiological and functional integration.
Biosynthesis of phospholipids and sphingolipids from acetoacetate and glucose in different regions of developing brain in vivo
Authors: Yeh Y.‐Y. 
Published: January 2005

AbstractThe incorporation of 14C‐label from subcutaneously injected [3‐14C]acetoacetate and [U‐14C]glucose into phospholipids and sphingolipids in different regions of developing rat brain was determined. In all regions, phosphatidylcholine was the lipid synthesized most readily from either substrate. The percentages of radioactivity in other phospholipids and most sphingolipids remained relatively constant throughout postnatal development. An exceptional increase in the percentage of radioactivity incorporated into cerebroside, coinciding with a decrease of incorporation into phosphatidylcholine, was first noted on day 12 and continued until a maximal level was reached between days 18 and 20 of postnatal age. These developmental changes in preferential synthesis of lipids were associated with increased demands for phospholipids and cerebroside during the early and late postnatal stages, respectively. There was no difference in accumulation of radioactivity from acetoacetate, expressed as dpm of [14C]acetoacetate recovered in phospholipids plus sphingolipids per g of tissue, among all brain regions during the first 5 days of life. During active myelination (12 to 20 days of age); however, the amount of 14C‐label was highest in brain stem, ranging from 1.9‐ to 2.3‐fold greater than values for cerebrum and thalamus. The region with the next highest accumulation was cerebellum, followed by midbrain. During the same period, brain stem was likewise the most active site of accumulation of radioactivity from 14C‐labeled glucose. Higher amounts of [14C]acetoacetate label accumulated in lipids of brain stem and cerebellum, relative to midbrain, thalamus, and cerebrum, coincide with evidence that active myelination begins in the hindbrain and proceeds rostrally toward the forebrain. Ketone bodies could therefore serve as a potential source of phospholipids and sphingolipids for brain growth and maturation.
Fetal calf serum‐mediated inhibition of neurite growth from ciliary ganglion neurons in vitro
Authors: Davis G. E. , Skaper S. D. , Manthorpe M. , Moonen G. , Varon S. 
Published: January 2005

AbstractEmbryonic chick ciliary ganglion (CG) neurons cultured in fetal calf serum‐containing medium have been previously reported to extend neurites on polyornithine (PORN) substrata precoated with a neurite‐promoting factor (PNPF) from rat schwannoma‐conditioned medium. On PORN substrata alone, however, no neuritic growth occured. This was interpreted as evidence that PORN was an incompetent substratum for ciliary neuritic growth. In this study, we now find that an untreated PORN substratum allows neuritic growth in serum‐free defined medium. When PNPF was added to PORN, a more rapid and extensive neuritic response occured. After 5 hr of culture, a 60% neuritic response occurred on PNPF/PORN, whereas no neurons initiated neurites until 10–12 hr on PORN. The inhibitory effect of fetal calf serum noted above on PORN could be obtained in part by pretreating the substratum with serum for 1 hr. Maximal inhibitory effects in the PORN pretreatment were achieved after 30 min and were not further improved by treatments up to 4 hr. Bovine serum albumin was also found to inhibit neurite growth on PORN to about 60% of the inhibition obtained by an equivalent amount of serum protein. Fetal calf serum was shown to cause a 15% reduction in the percentage of neurons bearing neurites after its addition to 18‐hr serum‐free PORN cultures and to cause statistically significant reductions in neurite lengths measured 2 hr later.
Biology of gangliosides: Neuritogenic and neuronotrophic properties
Authors: Ledeen R. W. 
Published: January 2005

AbstractResearch on the biologic function of gangliosides has accelerated in recent years following discovery of their pronounced effects when administered exogenously to neurons in culture and in vivo. These effects are of two principal types: (1) neuronotrophic, concerned primarily with survival and maintenance of the neuron, and (2) neuritogenic, involving significant increase in the number, length, and/or branching of neuronal processes. Such neurite‐promoting activity has been observed in primary cultures of neurons from brain and ganglia as well as transformed lines of neuronal origin. These phenomena may be related to the remarkable growth of aberrant secondary neurites, often accompanied by synaptogenesis, observed in the gangliosidoses. Several in vivo studies have shown exogenously administered gangliosides to aid nervous system repair in both the CNS and PNS, although it is not clear in some cases whether the observed effects should be attributed to neuronotrophic or neuritogenic effects (or both). This article attempts to briefly review the principal developments that have occurred in this area of ganglioside research over the past several years. It also presents for consideration some of the tentative hypotheses put forward concerning mechanism of action.
Antibodies to gangliosides inhibit goldfish optic nerve regeneration in vivo
Authors: Sparrow J. R. , McGuinness C. , Schwartz M. , Grafstein B. 
Published: January 2005

AbstractIntraocular injection of antiserum to mixed ganglioside or to GM1 inhibited the regeneration of goldfish optic axons following an optic nerve crush. For example, injections of antiserum on 5 consecutive days beginning the day before the crush resulted in a decrease of about 40% in the axonal outgrowth distance measured at 10 days after the crush. The inhibition was observed even when the treatment was begun a few days after the lesion, and greater degrees of inhibition were observed when the treatment was given later in regeneration. This indicates that the antiganglioside serum interfered with axonal elongation more than with the initial sprout formation. The antiganglioside treatment did not impair the enlargement of the cell bodies and nucleoli that accompanies regeneration, nor did it affect fast axonal transport of protein, glycoprotein, or glycolipid in regenerating nerves. Thus inhibition of outgrowth by antiganglioside treatment was not mediated by a gross change in the metabolism of the regenerating neurons. Treatment of normal neurons with the antiserum produced a 20–30% increase in the amount of 3H‐glucosamine‐labeled glycoproteins and glycolipids conveyed by fast axonal transport. These results suggest that membrane gangliosides may normally influence the supply of axonally transported glycosylated macromolecules. However, the effect of antiganglioside on axonal transport of glycosylated molecules and on axonal outgrowth are not necessarily related to each other.
The functional recovery of damaged brain: The effect of GM1 monosialoganglioside
Authors: Toffano G. , Savoini G. , Aporti F. , Calzolari S. , Consolazione A. , Maura G. , Marchi M. , Raiteri M. , Agnati L. F. 
Published: January 2005

AbstractIn the present study the topology and the biochemical mechanisms underlying the functional recovery of the dopaminergic nigrostriatal system is further analyzed. Rats with unilateral hemitransection were treated with 30 mg/kg GM1 monosialoganglioside or with its internal ester derivative for different periods of time. GM1 enhances 3H‐dopamine uptake in striatal synaptosomes of the lesioned side, and the enhancement of dopamine uptake precedes that of striatal tyrosine hydroxylase activity. The above biochemical effects are accompanied by changes in behavioral‐and electrophysiological‐related parameters. The effect of GM1 on striatal tyrosine hydroxylase of the lesioned side disappears when the ascending dopaminergic fibers are extensively lesioned. This suggests that the source of regrowing dopaminergic nerve terminals in the striatum of partially lesioned rats resides mainly in the intact axons remaining in the ipsilateral side. When GM1 is injected into partially lesioned rats kept in darkness, no effect on tyrosine hydroxylase activity is observed. This indicates that the mechanism through which GM1 acts involves a normal light‐dark cycle.
Neuron‐specific growth cone properties as seen in identified neurons of Helisoma
Authors: Haydon P.G. , Cohan C.S. , McCobb D.P. , Miller H.R. , Kater S.B. 
Published: January 2005

AbstractBy using cell‐cultured identified neurons of the snail Helisoma, we demonstrate that the growth cones of different neurons are intrinsically different from one another in terms of their structure, behavior, and response to environmental signals. Structurally neuron 5 has a greater number of filopodia per growth cone, has shorter filopodia, and has a smaller interfilopodial distance than neuron 19. Behaviorally, the growth cones of neuron 5 advance over the substratum at a faster rate than those of neuron 19; and the growth cones of neuron 19, but not of neuron 5, respond to the presence of serotonin in their environment by retracting their filopodia.In addition to such intrinsic differences between the growth cones of different neurons, we also demonstrate that the separate growth cones of a single neuron, while having identical properties, can act independently of one another. Focal application of serotonin to a growth cone causes only a localized retraction of that growth cones' filopodia. Other growth cones that are attached to the same neuron but that are not exposed to serotonin retain their normal structural features.
Guidance of neurite outgrowth by pathways of substratum‐adsorbed laminin
Authors: Hammarback J.A. , Palm S.L. , Furcht L.T. , Letourneau P.C. 
Published: January 2005

AbstractNeurite outgrowth is guided by narrow pathways of bioactive laminin. These pathways are created by ultraviolet light irradiation of laminin‐coated coverslips masked with electron microscope grids. Patterned outgrowth of neurites is independent of gross mechanical guidance and guidance caused by substrate limitation. Cells on unirradiated laminin are less readily displaced by shear forces than cells on irradiated laminin. This study suggests that ultraviolet light alters the adhesive properties of laminin and that differential cell‐substratum adhesion may guide extending neurites on the purified naturally occurring substance, laminin.
Taurine deficiency in the developing cat: Persistence of the cerebellar external granule cell layer
Authors: Sturman J.A. , Moretz R.C. , French J.H. , Wisniewski H.M. 
Published: January 2005

AbstractDietary taurine deprivation adversely affects feline pregnancy and is associated with the frequent occurrence of fetal resorption, abortion, stillbirth, and low birthweight of live kittens at term. Taurine‐deprived, live‐born kittens have a poor postnatal survival rate and grow less well than kittens from taurine‐supplemented queens. The postnatal dietary taurine intake of such kittens is reduced if they are nursed by their biologic mothers; the concentration of taurine in milk of taurine‐deprived mothers is less than 10% of that in milk from taurine‐supplemented queens. Surviving kittens from taurine‐deprived mothers exhibit a constellation of neurological abnormalities (abnormal hind leg development, a peculiar gait characterized by excessive abduction and paresis, and thoracic kyphosis readily visible by X‐ray). These findings suggest the presence of a developmental cerebellar deficit. Histological examination of the pre‐ and postnatally taurine‐deprived kitten's cerebellum reveals a persistence of the external granule cell layer, which was confirmed by electron‐microscopic examination. Numerous mitotic figures are present in the cells in the external granule cell layer of the cerebellum of kittens born from and nursed by taurine‐deprived queens, but not in those from taurine‐supplemented mothers. These findings suggest a maturational delay.
Immunohistochemical localization of myelin basic protein in the developing optic system of trout
Authors: Jeserich G. , Jacque C. 
Published: January 2005

AbstractImmunofluorescent localization of basic protein (BP) in the CNS of trout was performed using a heterologous antiserum raised against human BP. Bright specific fluorescence was confined to the myelin sheath of axons in most regions of the brain, whereas neuronal pericarya and dendrites as well as glial cells were entirely negative. In the tectum immunofluorescence was characteristically distributed in two rows of horizontally aligned patches, most evidently reflecting the orderly array of myelinated fiber bundles in the stratum opticum and stratum album. During development of the retino‐tectal pathway, the appearance of BP followed a distinct rostro‐caudal gradient firstly reaching the anterior ventral border of the tectum by larval stage 34. Furthermore, on cross sections through the optic nerve a specifically organized pattern of myelin formation was revealed by immunohistochemistry, which strikingly coincided with the pattern of fiber outgrowth.
Quantitation of the in vitro neuroblastoma response to exogenous, purified gangliosides
Authors: Leskawa K.C. , Hogan E.L. 
Published: January 2005

AbstractIndividual ganglioside species (possessing the gangliotetrose oligosaccharide) were purified from bovine brain gray matter and applied in varying concentrations to the culture medium of mouse neuroblastoma cells (N2A) in vitro. After 48 hr of incubation, the cells were stained, and the neuritogenic response quantitated with a video analysis system, employing a program to measure three parameters of neuroblastoma differentiation: neurites per cell (sprouting), neurite length (extension), and degree of neurite branching (arborization). All the individual gangliosides tested promoted neurite extension in a dose‐dependent fashion. Asialogangliosides (“neutral” glycosphingolipids) were without effect, which suggests that sialic acid (N‐acetylneuraminic acid) is necessary to elicit this cellular response. With increasing concentrations of GM1 (5 to 500 μg/ml), the average cellular neurite length increased significantly, whereas the number of neurites per cell decreased. With the trisialoganglioside GT1b, neurite length did not increase to the extent seen with GM1, but an increase in the number of neurites per cell (sprouting) and branch points per neurite (arborization) was observed. These results suggest that the in vitro neuronal response to exogenous gangliosides may combine specific responses to individual species making up the total.
Asymmetric molecular forms of acetylcholinesterase in mammalian skeletal muscles
Authors: Sketelj J. , Brzin M. 
Published: January 2005

AbstractVelocity sedimentation analysis of acetylcholinesterase (AChE) molecular forms was performed separately in endplate‐rich and endplate‐free regions of the diaphargm muscle of the rat, guinea pig, rabbit, dog, and pig, and in mm. erectores trunci and m. vastus lateralis in man. Several high‐ionic‐strength media were first tested to achieve better solubilization of AChE from rat muscles than by the usual 1 M NaCl‐ Triton X‐100 medium. Ninety‐five percent of the rat diaphragm was solubilized in a single extraction step by medium containing 1 M lithium chloride instead of NaCl. Homologous molecular forms of AChE were found in all species. The asymmetric forms were invariably present in the endplate regions of muscles but their activity in endplate‐free regions was much lower than in endplate regions in all investigated mammals except in man. Essentially the same pattern of AChE molecular forms was present in both regions in human muscles. High extrajunctional activity of the asymmetric forms makes human muscles similar to immature rodent muscles in vivo and in culture. The pattern of AChE molecular forms in the endplate region of the diaphragm in senile 24‐month‐old rats was not significantly different from that in 3‐month‐old animals. The persistence of the asymmetric AChE forms in the diaphragm of senile rats suggests that neuromuscular interactions do not become deficient with age in this muscle.
Excitatory effect of amino acids on identified neuron R14 of Aplysia. I. Glycine‐induced depolarization and its ionic mechanism
Authors: Ichinose M. , Sawada M. , Maeno T. 
Published: January 2005

AbstractThe ionic mechanism of the membrane effect of glycine on identified neuron R14 of Aplysia was investigated with conventional intracellular recording and voltage‐clamp techniques. Both localized and bath applications of glycine markedly depolarize R14. Bath‐applied glycine induced an inward current that gradually reached a maximum and remained at that level until glycine was washed out. Displacement of the holding potential from –46 to –121 mV increased the inward current. The extrapolated reversal potential was +38.6 mV. Reduction of [Na+]o reversibly decreased the inward current. Alterations of [K+]o, [Cl−]o, and [Ca2+]o, as well as bath‐applied ouabain and sodium cyanide, did not affect the inward current. These results suggest that glycine can induce an Na+ current and that the glycine‐induced inward current does not reflect an active uptake by an Na+‐coupled transport system of glycine into the neuron.
Development of mouse spinal cord in tissue culture: IV. Effects of embryonic extracts on neuron formation and migration
Authors: Houle J. D. , Fedoroff Sergery 
Published: January 2005

AbstractPossible influences upon patterns of neurogenesis expressed in vitro were examined quantitatively by the use of microfragment cultures of embryonic day 10 mouse neural tube. Crude extracts were prepared either from whole embryos (day 13 or 15 of gestation) or from embryonic brains (day 18 of gestation) and added to the culture medium for the first 10 days of culturing. Neuronal outgrowth zones surrounding individual microfragments were reduced in area (indicating restricted neuronal migration) and in number of neurons present (indicating restricted production of neurons) following treatment with either of the extracts. The severity of reductions observed were related to the developmental age of embryonic tissue used for preparing the extract, as greatest reduction resulted from addition of embryonic day 18 brain extracts and to concentration employed, higher doses further restricting neuronal outgrowth. By increasing the concentrations of extract the proportional number of large‐sized neurons forming the outgrowth zones became greater relative to the small neuron contribution, indicating an enhanced survival for this neuronal population. The formation and migration of astroglial precursor cells was not affected by the addition of any of the extracts.The number of neurons remaining within the original portions of neural tube microfragments was not significantly altered following culturing in the presence of embryonic extract. This suggested that the reduction in neuron number in the outgrowth zone actually reflected a decreased neuron production and was not simply the result of a retention of neurons within the remaining portion of the microfragment
.The results suggest the presence of substances within mouse embryos that have regulatory effects on aspects of development of the central nervous system. Indications are that survival and maturation of postmitotic neuroblasts are promoted in vitro while the formation of additional neuronal progenitor cells may be partially inhibited by the addition of embryonic mouse extracts to the medium. We propose that an endogenous negative feedback mechanism may be invloved in the coordination of patterns of neurogenesis.