bluuebunny/crossref_metadata_2025_split huggingface dataset:
The process of reinnervation in the dentate gyrus of the adult rat: A quantitative electron microscopic analysis of terminal proliferation and reactive synaptogenesis
Authors: Steward Oswald , Vinsant Sharon L. 
Published: December 2004

AbstractThe present study defined the time course of terminal proliferation (the growth of presynaptic processes) and reactive Synaptogenesis in the dentate gyrus of the adult rat. Quantitative electron microscopic analyses were carried out in the dentate gyrus 2, 4, 6, 8, 10, 12, 14 days and 7 months after destruction of the ipsilateral entorhinal cortex and in the contralateral (control) dentate gyrus. At each survival interval, counts were made from photographic montages of (1) terminals (presynaptic processes with or without contacts with postsynaptic elements), (2) intact synapses, (3) degenerating synapses, (4) degeneration (degenerating presynaptic processes), and (5) multiple synapses (terminals making more than one synaptic contact). Terminal density was initially reduced to about 13% of control in the middle molecular layer at 2 and 4 days postlesion, and to about 26% of control in the outer. The density of terminals began to increase between 4 and 6 days postlesion, reaching a plateau by day 12. Synapse density was reduced to about 8% and 12% of control in the middle and outer molecular layer respectively. Synapse density increased about 5‐fold between 8 and 12 days postlesion, but continued to increase in the period between 14 days and 7 months postlesion. At 2 days postlesion, the number of intact terminals that are lost corresponds to the number of degenerating presynaptic processes. This correspondence is not present at 4 days postlesion, however, suggesting a rapid removal of degenerating terminals. In contrast, even at 2 days post‐lesion, the number of intact synapses that are lost does not correspond to the number of degenerating synapses. Between 2 and 10 days postlesion, the number of postsynaptic specializations is about 60% of control, but recovers slightly by 12‐14 days postlesion. Qualitative and quantitative evidence suggested a collapse of spines into configurations that resembled shaft synapses. There appeared to be a deformation of degenerating presynaptic processes resulting in the appearance of multiple synapse configurations prior to reinnervation. The combined results suggest that terminal proliferation precedes reactive Synaptogenesis in the dentate gyrus by 2‐4 days, that terminal proliferation is essentially complete by 12 days while reactive Synaptogenesis continues, and that multiple synapses arise at least in part as a result of a deformation of degenerating presynaptic processes rather than as a consequence of the induction of additional contacts on existing presynaptic terminals.
Tyrosine hydroxylase immunoreactive neurons and fibers in the olfactory system of the hamster
Authors: Davis Barry J. , Macrides Foteos 
Published: December 2004

AbstractTyrosine hydroxylaselike immunoreactivity is associated with several different classes of neurons in the main olfactory bulb of the hamster. Most of the tyrosine hydroxylaselike immunoreactive (THLI) neurons are located in the glomerular layer and in the outer two‐thirds of the external plexiform layer. The majority of THLI neurons in the glomerular layer have somal sizes and dendritic features which correspond to those of external tufted cells. A small population of THLI periglomerular cells also is present. The majority of THLI neurons in the external plexiform layer have the morphological characteristics of middle tufted cells. A small population of THLI neurons which appear to be Van Gehuchten cells is distributed throughout the external plexiform layer and in the mitral body layer. Small populations of THLI deep short‐axon cells are distributed throughout the mitral body, internal plexiform, and granule cell layers. Tyrosine hydroxylase‐positive fibers of central origin also are observed in the main olfactory bulb. They may originate from THLI neurons in the anterior olfactory nucleus, ventral hippocampal rudiment, dorsal peduncular cortex, septal and basal portions of the vertical limb and nucleus of the horizontal limb of the diagonal band, lateral and dorsal hypothalamus, ventral tegmental area and substantia nigra, dorsal and median raphe nuclei, and locus ceruleus. The frontal neocortex, infralimbic and anterior cingulate cortex, and medial amygdaloid nucleus also contain THLI neurons.In contrast to the widespread distribution of tyrosine hydroxylaselike immunoreactivity in the main olfactory bulb, substance P‐like immunoreactivity is restricted to external tufted cells and to centrifugal afferents which may originate in the dorsal and median raphe nuclei. Both types of immunoreactivity appear to be present in centrifugal afferents to the accessory olfactory bulb, but THLI neurons are extremely rare and no neurons with substance P‐like immunoreactivity have been observed in the accessory olfactory bulb. Intraventricular injections of colchicine which were expected to enhance the labeling of neuronal somata did not alter the relative incidences of labeling among the various classes of neurons in the olfactory bulbs.These findings provide immunocytochemical evidence that populations of superficially situated tufted cells in the main olfactory bulb are functionally distinct from the deeper‐lying output neurons and from output neurons in the accessory olfactory bulb, that populations of catecholami‐nergic neurons are present within several olfactory and related cortical structures in addition to the olfactory bulbs, that the medical septum‐diagonal band complex also contains catecholaminergic neurons, and that a substantial population of neurons in the dorsal raphe nucleus is capable of vatechol synthesis.
The sources of supraspinal afferents to the spinal cord in a variety of limbed reptiles. I. Reticulospinal systems
Authors: Newman Donald B. , Cruce William L. R. , Bruce Laura L. 
Published: December 2004

AbstractHorseradish peroxidase was injected into various levels of the spinal cord of turtles (Pseudemys and Chrysemys), lizards (Tupinambis, Iquana, Gekko, Sauromelus, and Gerrhonotus), and a crocodilian (Caiman). The results suggest that brainstem reticulospinal projections in limbed reptiles rival mammalian reticulospinal systems in complexity. The reptilian mye‐lencephalic reticular formation can be divided into four distinct reticulospinal nuclei. Reticularis inferior pars dorsalis (RID) contains multipolar neurons which project bilaterally to the spinal cord. Reticularis inferior pars ventralis (RIV), which is only found in lizards and crocodilians, contains fusiform neurons with horizontally running dendrites and it projects ipsi‐laterally to the spinal cord. Reticularis ventrolateralis (RVL), which is found only in teiid lizards, contains triangular neurons whose dendrites parallel the ventrolateral edge of the brainstem and it projects ipsilaterally to the spinal cord. The myelencephalic raphe (Ral) varies considerably. Ral of turtles contains large reticulospinal neurons which form a continuous population with more laterally situated RID cells. Ral of lizards contains a few small reticulospinal neurons. Ral of the crocodilian Caiman contains giant reticulospinal neurons with laterally directed dendrites.The caudal metencephalic reticular formation of reptiles can be divided into two distinct reticulospinal nuclei. Reticularis medius (RM) contains large neurons with long, ventrally directed dendrites; it projects ipsilaterally to the spinal cord. Reticularis medius pars lateralis (RML) contains small neurons with laterally directed dendrites; it projects contralaterally to the spinal cord.The rostral metencephalic and caudal mesencephalic reticular formation of reptiles can be divided into three distinct reticulospinal nuclei. Reticularis superior pars medialis (RSM) consists mostly of small, spindle‐shaped neurons which project bilaterally to the spinal cord. In the lizard Tupinambis, however, large multipolar, ipsilaterally projecting neurons are occasionally seen in RSM. Reticularis superior pars lateralis (RSL) contains large, bilaterally projecting neurons with long, ventrolaterally directed dendrites. RSL in lizards can be divided into a dorsomedial portion, which projects ipsilaterally to the spinal cord, and a ventrolateral portion which projects contralaterally. The locus ceruleus‐subceruleus field (LC‐SC) contains small spindle‐shaped neurons which project bilaterally to the spinal cord.Labeled reticulospinal neurons were also observed in the rostral metencephalic raphe (RaS) of the turtle brainstem. These cells are small, spindle‐shaped neurons which resemble the small cells of the adjacent RSM field.
The superior vestibular nucleus: An intracellular hrp study in the cat. II. Non‐vestibulo‐ocular neurons
Authors: Mitsacos Ada , Reisine Harvey , Highstein Stephen M. 
Published: December 2004

AbstractSuperior vestibular neurons were penetrated with horseradish perox‐idase (HRP)‐loaded glass microelectrodes in anesthetized cats and identified electrophysiologically following electrical stimulation of the vestibular nerves and oculomotor complex. Neurons that were not antidromically activated from the oculomotor complex were stained by intracellular injection of horseradish peroxidase.Three types of neurons are identified according to their initial axonal trajectories into the cerebellum, the dorsal pontine reticular formation, or the brachium conjunctivum. Ipsilateral vestibular nerve input to all neurons is primarily monosynaptic and excitatory, whereas the contralateral is inhibitory.The neurons are located in the periphery of the superior vestibular nucleus. Soma diameters range from 20.5 μm to 44 μm. Most neurons exhibit globular and ovoid cell bodies. The dendritic arbors are intermediate between iso‐ and allodendritic branching patterns. The few spines and dendritic appendages present are distributed mainly distally on the dendrites. Soma size does not correlate with axon diameter, number of dendrites, or dendritic territories.
Morphometric analysis of granule cell dendrites in the mouse dentate gyrus
Authors: Williams Roger S. , Matthysse Steven 
Published: December 2004

AbstractWe devised a computer program to analyze the dendritic geometry of dentate granule cells as seen in rapid Golgi impregnations from the mouse. Three dimensional coordinates were recorded by using a computer‐assisted microscope. Geometric parameters are of two general types: (1) LINEAR parameters include the number of dendritic segments per branch order and their individual and aggregate lengths. (2) ANGULAR parameters define the spatial relationships of branch points and segment terminals with each other and with the axis of symmetry derived for all the dendrites. We find that values for linear parameters are highly variable and more susceptible to artifacts. Values for most angular parameters are more highly constrained and are presumably the best descriptors of the class‐characteristic conical shape of granule cell dendrites. Additional features which are necessary to describe granule cell dendrites fully are: (1) Branching frequency is highest proximal to the cell soma, (2) deviant segments are kept “on course” to ensure axial symmetry, and (3) terminal segments end at the plane of the cortical surface. A critical analysis of the various parameters suggests the hypothesis that the characteristic and uniform geometry of granule cell dendrites is controlled largely by factors residing in the molecular layer where growth and differentiation are sustained. An additional finding of potential interest is that there are two subpopulations of granule cells with a twofold difference in spine density.
Cerebellar corticonuclear projections in the red‐eared turtle Pseudemys scripta elegans
Authors: Bangma G. C. , Donkelaar H. J. Ten , Pellegrino A. 
Published: December 2004

AbstractIn the present study the organization of the corticonuclear projections of the cerebellum in the red‐eared turtle Pseudemys scripta elegans was investigated. To find out whether a zonal pattern exists in the cerebellar cortex, a topological analysis was made of the Purkinje cell layer of a Nissl‐stained series of the cerebellum. This analysis showed a distinct, longitudinally oriented zonal pattern of Purkinje cells. In each cerebellar half a medial, an intermediate, and a lateral zone could be distinguished. This pattern appeared to correspond in part to an earlier subdivision of the reptilian cerebellum suggested by Larsell (1926, 1932, 1967).In the experimental part of this study, the corticonuclear projections to the cerebellar nuclei and the vestibular nuclear complex were demonstrated with the horseradish peroxidase (HRP) technique. All projections of the Pur‐kinje cells appeared to be strictly ipsilateral. After HRP slow‐release gel implantations at various levels of the vestibular nuclear complex, longitudinally oriented areas of labeled Purkinje cells were found in the lateal part of the medial zone, the intermediate zone, and the lateral zone. Two strips of Purkinje cells remained unlabeled: One in the rostrolateral part of the intermediate zone, and another in the medial part of the medial zone. After HRP gel implantations in the cerebellar peduncle aimed at the medial and lateral cerebellar nuclei, respectively, Purkinje cells in the latter two strips were labeled. The present results indicate that the corticonuclear projections to the medial cerebellar nucleus arise in the medial part of the medial zone and those to the lateral cerebellar nucleus in the rostrolateral part of the intermediate zone.It can be concluded that cerebellar zones, as demonstrated in the turtle Pseudemys scripta elegans, are phylogenetically very old and may represent the basic functional circuit of the cerebellum.
Lesion‐induced mossy fibers to the molecular layer of the rat fascia dentata: Identification of postsynaptic granule cells by the Golgi‐EM technique
Authors: Frotscher Michael , Zimmer Jens 
Published: December 2004

AbstractThe axons of the dentate granule cells, the hippocampal mossy fibers, sprout “backward” into the dentate molecular layer when this is heavily de‐nervated. Using the combined Golgi‐electron microscopy (EM) technique we now demonstrate that these aberrant supragranular mossy fibers at least in part terminate on granule cell dendrites.Sprouting of mossy fibers into the dentate molecular layer was induced in adult rats by simultaneous surgical removal of the commissural and ento‐rhinal afferents to the fascia dentata. After at least 7 weeks survival, the presence of mossy fiber terminals in the inner part of the dentate molecular layer was demonstrated by light microscopy of Timm‐stained cryostat sections and by electron microscopy. In the electron microscope the mossy fiber terminals were identified by their unique structural characteristics, namely, the unusually large size of the terminals, the dense packing of clear synaptic vesicles with a few dense core vesicles intermingled, the presence of asymmetric synaptic contacts with spines and desmosome‐like contacts with dendritic shafts, and the continuity with a thin unmyelinated preterminal axon.Golgi‐stained granule cells were first identified in the light microscope, and then, after deimpregnation, the same cells were examined in the electron microscope. In ultrathin, serial sections lesion‐induced mossy fiber terminals were found in synaptic contact with spines on proximal dendritic segments of such identified Golgi‐impregnated granule cells. From this we conclude that the aberrant, supragranular mossy fibers can innervate dendrites of the parent cell group, the dentate granule cells. The results, moreover, provide an example of reactive synaptogenesis where both the sprouted afferents and its postsynaptic element have been identified.
Cloned microglial cells but not macrophages synthesize β‐endorphin in response to CRH activation
Authors: Sacerdote Paola , Denis‐Donini Suzanne , Paglia Paola , Granucci Francesca , Panerai Alberto E. , Ricciardi‐Castagnoli Paola 
Published: December 2004

AbstractThe properties of microglial cell clones, obtained from embryonic mouse brain primary cultures immortalized with recombinant retroviruses, have been investigated and compared with the properties of macrophage clones similarly obtained. Macrophage clones differed from microglial clones in some functions but shared most of the immunological properties. Interestingly, microglial cells were able to produce β‐endo‐rphin, and this production was regulated differently in microglial cell clones when compared with macrophage clones. Although lipopolysaccharide (LPS) treatment induces an increase in β‐endorphin concentration in both cell types, only microglial clones and primary microglial cell cultures respond to the neuroendocrine stimulus corticotropin releasing hormone (CRH). In addition, in these cells, β‐endorphin release is regulated by a classical neurotransmitter, such as noradrenaline, adding some evidence of communication between neurons and microglial cells. © 1993 Wiley‐Liss, Inc.
Three‐dimensional analysis of clustered voxels in 15O‐butanol brain activation images
Authors: Roland P. E. , Levin B. , Kawashima R. , Åkerman S. 
Published: December 2004

AbstractChanges in the regional cerebral blood flow (rCBF) are often used as an indicator of changes in local neuronal activity of the brain. We present here quantitative measurements with positron emission tomography (PET) of rCBF with a freely diffusible flow tracer 15O‐butanol in control and activation states, and a pixel‐by‐pixel statistical parametric analysis of the rCBF changes combined with a cluster analysis. Anatomically standardized rCBF activation data from 39 normal subjects were analyzed for the occurrence of clustered voxels. Noise data was obtained from repeat measurements of rCBF with the brain in the activated state and from simulations. The variance in test‐control images was largest outside the skull, and large in soft tissue regions around the brain. It was moderate but inhomogenous in gray matter, and low and homogenous in white matter. A special picture was generated of the conformation of sampled data with a normal distribution. In the gray and white matter, the pixel values were fount to conform to a normal distribution, permitting calculation of Student's t‐images. In the cluster analysis, activations are detected as clusters of voxels with high t‐values. The clusters in activated regions, however, were considerably larger than the full width half‐maximum of spatial autocorrelation function and were easily detected. Tables of the empirical Poisson‐like distributions of the number of clusters of different sizes are provided, from which P values of the significance of the occurrence of clusters of different sizes can be estimated. © 1993 Wiley‐Liss, Inc.
Time‐dependent changes in effective connectivity measured with PET
Authors: Friston K. J. , Frith C. D. , Frackowiak R. S. J. 
Published: December 2004

AbstractA voxel‐based method of measuring the effective connectivity between brain regions is presented. The approach is based on electrophysiological concepts and is applied to neurophysiological data obtained with [positron emission tomography (PET)] functional imaging. Time‐dependent changes in effective connectivity were assessed during a verbal fluency activation paradigm using 12 consecutive measurements of regional cerebral blood flow (rCBF). The changes observed were predicted by an associative (Hebbian) model of plasticity, applied to cortical activity, measured in terms of rCBF. The main finding was, in most regions, a selective enhancement of effective connections from the distributed brain regions exhibiting the dominant pattern of correlated activity. © 1993 Wiley‐Liss, Inc.
Zur Konstitution des Molybdänblaus
Authors: Treadwell W. D. , Schaeppi Yvonne 
Published: December 2004

Abstract1. Elektrolytisch hergestelltes Molybdänblauoxydhydrat wurde oxydimetrisch und konduktometrisch titriert. Der Gefrierpunkt der sulfatfreien Lösung wurde bestimmt. Aus diesen Messungen ergab sich, dass die wässrige Lösung des Molybdänblauoxydhydrats 1 H·‐Ion pro ½ Mo2O5·2 MoO3 enthält. Es wurde eine Konstitutionsformel für das Blau vorgeschlagen, welche die tiefe Färbung und die Tendenz zur Bildung eines negativen Sols verständlich macht.
Le dosage de l'alcool éthylique sanguin: Une modification de la méthode de Nicloux
Authors: Rochat J. 
Published: December 2004

Abstract1. La technique de dosage de l'alcool sanguin, décrite dans ce travail, est basée sur l'ancien procédé de Nicloux, modifié à deux points de vue: a) détermination de l'excès de K2Cr2O7 par manganimétrie; b) interversion de l'ordre d'addition des réctifs et augmentation de la proportion d'acide sulfurique.
Über adaptive Enzyme bei parasitischen Pilzen I
Authors: Gäumann Ernst , Böhni Erika 
Published: December 2004

AbstractEs wurde die Frage geprüft, ob und in welchem Umfange bei Botrytis cinerea Pers. die Bildung von Pektinase und von Pektase durch den Pektingehalt einer bestimmten Nährlösung beeinflusst wird. Die Pektinase, welche die Pektatkette aufspaltet, erwies sich dabei als ein konstitutives Enzym, das unabhängig von der chemischen Zusammensetzung der Nährlösung entsteht. Die unspezifische Pektase, welche die Pektine demethoxyliert, erwies sich dagegen als ein weitgehend adaptives Enzym, das nur in Gegenwart von Pektin reichlich, ohne Pektin dagegen bloss in Spuren gebildet wird.
Relaxationszeitspektrum, Elastizität und Viskosität von Kautschuk I
Authors: Kuhn W. , Künzle O. , Preissmann A. 
Published: December 2004

AbstractBei rascher Deformation eines Mediums, in welchem sich Fadenmolekel befinden, werden an den letzteren gleichzeitig verschiedene Änderungen hervorgebracht. Die Änderungen sind voneinander mehr oder weniger unabhängig und können durch Neuordnung der Abstands‐ und Winkelverteilung ganz oder teilweise rückgängig gemacht werden. Zufolge solcher Relaxationsvorgänge verschwindet ein Teil der bei rascher Deformation zunächst entstandenen Spannungen, jedoch mit einem für die verschiedenen Spannungsanteile wechselnden Zeitbedarf. Es entsteht ein Relaxationszeitspektrum.
Über die polarographische Reduktion der aliphatischen Aldehyde. II. Oszillographisch‐polarographische Untersuchungen am Formaldehyd
Authors: Bieber R. , Trümpler G. 
Published: December 2004

Abstract1. Die von Heyrovsky und Forejt eingeführte oszillographische Messung der polarographischen Potential‐Zeit‐Kurven wurde in ausführlicherer Weise dargestellt. Das Entstehen und die Auswertung der dabei beobachtbaren Effekte wurde speziell für organische Depolarisatoren erläutert.
Über Pterinchemie. 57. Mitteilung. Zur Konfiguration und Konformation von 6,7‐Dimethyl‐und 5,6,7‐Trimethyl‐5,6,7,8‐tetrahydropterin
Authors: Weber Rudolf , Viscontini Max 
Published: December 2004

Configuration and conformation of 6,7‐Dimethyl‐ and 5,6,7‐Trimethyl‐5,6,7,8‐tetrahydropterines.During the hydrogenation of 6,7‐dimethylpterine, cis‐6,7‐dimethyl‐tetrahydropterine is formed. A possible conformation for this substance and for the 5,6,7‐trimethyl derivative, which is obtained from it, is discussed, taking the 1H‐NMR. spectra of both tetrahydropterines into consideration.
Adducts of niobium(V) and tantalum(V) halides. XIV. Structure and relative stability of the adducts with some phosphoryl compounds
Authors: Favez Christian M. P. , Rollier Henri , Merbach André E. 
Published: December 2004

AbstractThe adducts of niobium(V) and tantalum(V) halides with some phosphoryl compounds have been studied in chloroform solution by 1H‐ and 19F‐FT‐NMR. spectroscopy. These octahedral adducts of general formula MX5 · L (M = Nb, Ta; X = F, Cl, Br; L = phosphoryl ligand) are monomeric and neutral. Their relative stability constants have been determined at −60°. The stabilities are controlled by electronic effects of substituents on the phosphoryl group.