bluuebunny/crossref_metadata_2025_split huggingface dataset:
Integrity of the blood‐brain barrier in retinal xenografts is correlated with the immunological status of the host
Authors: Young Michael J. , Rao Kanchan , Lund Raymond D. 
Published: January 2005

AbstractThe purpose of this study was to determine the immunological correlates of blood‐brain barrier breakdown in retinal xenografts in rats by utilizing skin grafting to initiate a timed immune response to the transplanted neural tissue. Embryonic day 13–14 CD‐1 mouse retinae were grafted into the brainstem parenchyma of neonatal Sprague‐Dawley rats. In one group of animals a 100 mm2 CD‐1 skin graft was placed on the flank 21 days after the initial neural transplant in order to provoke an immune response to the neural graft. Control animals received no skin graft. Animals were injected with horseradish peroxidase (HRP) in the femoral vein 2–8 days after skin grafting. Brains were processed for Nissl, HRP‐tetramethylbenzidine, and anti‐M‐6, ‐lymphocyte, ‐macrophage, and ‐astrocyte antibodies. Experimental and control animals injected 2–4 days after skin grafting showed no leakage of reaction product in the grafted tissue. A small percentage (one of eight) of 5‐day animals showed isolated, patchy leakage, but no evidence of rejection of the neural graft. At 6 days all of the grafts showed evidence of leakage, and 71% of these grafts showed infiltration of lymphocytes. By 7–8 days extensive leakage of HRP and widespread infiltration of lymphocytes and macrophages were clearly evident.The present study demonstrates that blood‐brain barrier breakdown is correlated closely with the sequence of immunological rejection of the graft. While these results confirm that a barrier exists in healthy neural transplants, they suggest that immunological factors should be considered in cases in which grafts are not protected by an intact barrier.
Structure of a tonically transmitting synapse between identified interneurone in the locust brain
Authors: Simmons Peter J. , Littlewood P. M. Henk 
Published: January 2005

AbstractThe ultrastructure and distribution of synapses between large second‐order and third‐order neurones of a locust ocellus are described. Pairs of neurones, shown by physiological tests to be connected by a tonically transmitting, excitatory connection, have been injected with hexamminecobaltic ions, which allows their profiles to be recognised with electron microscopy. The synapses are made in the lateral ocellar tract, between the axons of some of the second‐order neurones and a network of fine processes from the third‐order neurone. A physiological connection is composed of several thousand discrete anatomical synapses. Each anatomical synapse is composed of a presynaptic density associated with a cloud of round, electron‐lucent vesicles overlying an intercellular cleft. Parallel with the presynaptic density is a row of omegashaped invaginations of the presynaptic plasmalemma. The synapses are diadic and are close to synapses from small, unidentified neuronal profiles onto the third‐order neurone.
Calbindin‐immunoreactive sensory neurons of dorsal root ganglion project to skeletal muscle in the chick
Authors: Philippe E. , Droz B. 
Published: January 2005

AbstractIn the chicken dorsal root ganglia, two neuronal subpopulations referred to as A1 and B1 share in common an immunoreactivity to antisera raised to calbindin D‐28k but are distinguished by their cytological and ultrastructural characteristics. To determine the peripheral targets innervated by calbindin‐immunoreactive neurons in lumbosacral dorsal root ganglia, cryostat sections of various hindlimb tissues were treated with anticalbindin antisera. Calbindin‐immunostained axons were clearly detected in skeletal muscle. Large myelinated nerve fibres and afferent axon terminals in neuromuscular spindles were calbindin‐immunoreactive; thin unmyelinated nerve fibres were also immunostained in nerve bundles of the perimysium. Since motoneurons and neurons of the autonomic nervous system were devoid of calbindin immunostaining, it was suggested that the immunoreactive axons found in skeletal muscle originate from sensory neurons expressing a calbindin immunoreaction in the dorsal root ganglia. This hypothesis was corroborated after introduction of wheat germ agglutinin coupled with horseradish peroxidase or colloidal gold particles into the sartorius muscle. The retrogradely transported tracer was collected only in ganglion cell bodies which displayed the ultrastructural characteristics of A1 and B1 sensory neurons. On the basis of calbindin immunoreaction and of tracer retrograde transport, it is concluded that ganglion cells of subclasses A1 and B1 contribute to the sensory innervation of skeletal muscle in the chicken.
Ultrastructural analysis of somatostatin‐immunoreactive neurons and synapses in the temporal and occipital cortex of the macaque monkey
Authors: De Lima Ana D. , Morrison John H. 
Published: January 2005

AbstractSomatostatin‐containing neurons and terminals have been analyzed in monkey temporal and occipital cortex by using light and electron microscopic immunohistochemistry. An antibody against Somatostatin‐28(1–12), that was shown previously preferentially to label fibers (Morrison et al.: Brain Research 262:344–351, 1983), was utilized. As expected, few cell bodies were labeled. At the electron microscopic level, labeled cells presented a characteristic asymmetric position of the nucleus and very few symmetric or asymmetric synapses on the somatic surface. In all areas examined, somatostatin fibers formed a dense plexus in the most superficial layers (I‐upper III). The density of labeled fibers in intermediate (deep III–IV) and deep layers (V–VI) varied considerably among areas. The synaptic relationships of the immunoreactive fibers were analyzed and postsynaptic targets quantified in V1, V2, and the superior and inferior temporal gyrus (STG and ITG, respectively). The synapses formed by somatostatin‐labeled boutons were of the symmetric type (type II) and the primary postsynaptic targets were dendritic shafts. No regional differences were found in the distribution of the postsynaptic targets in layers I‐upper III. The pattern of synapses in the deep layers was examined in STG. The frequency and distribution of postsynaptic targets was similar to the superficial layers of STG and the other temporal and occipital regions. In intermediate layers of the temporal cortex areas there was an increase in the proportion of synapses on dendritic spines. In a correlated light and electron microscopic analysis we examined synapses made by radial fibers in these regions and found that although the main targets are distal dendritic shafts, almost 40% of synapses were on dendritic spines. We suggest that the radial fibers may originate from a specialized interneuron, previously described as the double bouquet cell, and that this particular subset of somatostatin‐containing double bouquet cells is likely to exhibit a very high degree of regional heterogeneity with a preference for association cortices with extensive cortico‐cortical convergence.
Monoaminergic, peptidergic, and cholinergic afferents to the cat facial nucleus as evidenced by a double immunostaining method with unconjugated cholera toxin as a retrograde tracer
Authors: Fort Patrice , Sakai Kazuya , Luppi Pierre‐Hervé , Salvert Denise , Jouvet Michel 
Published: January 2005

AbstractUsing a sensitive double immunostaining technique with unconjugated cholera‐toxin B subunit as a retrograde tracer, the authors determined the nuclei of origin of monoaminergic, peptidergic, and cholinergic afferent projections to the cat facial nucleus (FN). The FN as a whole receives substantial afferent projections, with relative subnuclear differences, from the following areas: (1) the perioculomotor areas, the contralateral paralemniscal region, and the mesencephalic reticular formation dorsal to the red nucleus; (2) the ipsilateral parabrachial region and the nucleus reticularis pontis, pars ventralis; and (3) the nuclei reticularis parvicellularis, magnocellularis, ventralis, and dorsalis of the medulla.In addition, the present study demonstrated that the lateral portion of the FN receives specific projections from the contralateral medial and olivary pretectal nuclei and the ipsilateral reticular formation of the pons. It was also found that the FN receives: (1) serotoninergic inputs mainly from the nuclei raphe obscurus, pallidus, magnus, and the caudal ventrolateral bulbar reticular formation; (2) catecholaminergic afferent projections from the A7 noradrenaline cell group located in the Kölliker‐Fuse, parabrachialis lateralis, and locus subcoeruleus nuclei; (3) methionin‐enkephalin‐like inputs originating in the pretectal complex, the nucleus paragigantocellularis lateralis and the caudal raphe nuclei; (4) substance P‐like afferent projections mainly from the Edinger‐Westphal complex and the caudal raphe nuclei; and (5) cholinergic afferents from an area located ventral to the nucleus of the solitary tract at the level of the obex.In the light of these anatomical data, the present report discusses the physiological significance of FN inputs relevant to tonic and phasic events occurring at the level of the facial musculature during the period of paradoxical sleep in the cat.
Connections of indoleamine‐accumulating cells in the rabbit retina
Authors: Sandell Julie H. , Masland Richard H. , Raviola Elio , Dacheux Ramon F. 
Published: January 2005

AbstractTo study the connections of the neurons of the rabbit retina that accumulate indoleamines, we injected 5,7‐dihydroxytryptamine into the vitreous body. It accumulated within a subset of amacrine cells and could be visualized there by aldehyde‐induced fluorescence. The fluorescent labeling was photoconverted to an insoluble, osmiophilic product by irradiation in the presence of diaminobenzidine, and the tissue was examined by electron microscopy. Preservation of the structure of the tissue after photoconversion was satisfactory and the dendrites of the indoleamine‐accumulating cells could easily be identified. They form a dense plexus near the junction of the inner plexiform and ganglion cell layers, where they exhibit large synaptic endings that occupy a substantial fraction of the surface of rod bipolar terminals. The dendrites of the indoleamine‐accumulating cells receive input from rod bipolars at dyad synapses, where the other postsynaptic partner is a dendrite of a narrow‐field, bistratified amacrine cell; in addition, they receive amacrine cell input throughout the inner plexiform layer. The only outputs we observed are reciprocal synapses onto the rod bipolar endings. Thus, these amacrine cells appear to exert an important effect on the transmission of scotopic information through the retina.
Synaptic organization of enkephalinlike‐immunoreactive amacrine cells in the goldfish retina
Authors: Watt Carl B. 
Published: January 2005

AbstractImmunoelectron microscopy was used to examine the synaptic organization of enkephalinlike‐immunoreactive amacrine cells in the goldfish retina. Enkephalin‐immunostained processes sometimes contained dense‐cored vesicles (115–145 nm) in addition to a generally homogeneous population of small, round, clear synaptic vesicles. A total of 194 synaptic relationships were observed that involved the immunostained processes of enkephalin‐amacrine cells. The large majority of these were observed in sublayer 5 of the inner plexiform layer. In greater than 95% of the synaptic relationships, the enkephalin‐immunostained profile served as the presynaptic element. In 58.8% of these relationships, enkephalin processes synapsed onto amacrine cell processes, while 30.4% of their synapses were onto processes that lacked synaptic vesicles. They also occasionally formed synaptic contacts (6.7%) onto the somas of cells located either in the inner nuclear or in the ganglion cell layers. Enkephalin profiles received synaptic input only from amacrine cells (4.1%), while no direct synaptic interaction was observed between enkephalin processes and bipolar cells. However, in sublayer 1, enkephalin profiles were found to synapse onto amacrine cell processes that were presynaptic to bipolar cell terminals. In the proximal inner plexiform layer, enkephalin processes were presynaptic to amacrine cell processes that as a group surrounded and sometimes provided synaptic input to extremely large and round bipolar cell endings.
Callosal connections of the somatic sensory areas II and IV in the cat
Authors: Barbaresi P. , Bernardi S. , Manzoni T. 
Published: January 2005

AbstractThe homotopic and heterotopic callosal connections in the forelimb representations of the second (SII) and fourth (SIV) somatic sensory areas of cats were investigated by means of the axonal transport of horseradish peroxidase (HRP) in conjunction with microelectrode recording. The tracer was injected in the electrophysiologically identified hand and/or digit zone of SII (six cats) or SIV (four cats). The homotopic area in the contralateral hemisphere was explored with microelectrodes in five animals (three injected in SII and two in SIV) to map neuronal receptive fields. The aim was to correlate in the same experimental case the topography of labelled callosal neurons with the physiological map of the forelimb. Labelled cells and recording sites were plotted on planar maps reconstructed with the aid of a computer from serial coronal sections from the anterior ectosylvian gyrus.After SII injections, labelled callosal neurons were observed throughout the forelimb representation in the contralateral area, but in the tangential plane their distribution was uneven. Each somatotopic zone composing the forelimb map, that is, the arm, hand, and digit zones, contained several subzones in which callosal neurons were either dense or rare. Microelectrode explorations showed that receptive fields mapped from callosal and relatively acallosal subzones representating the same body part were similar in extent and location. After SIV injections, labelled callosal neurons were observed throughout the forelimb and proximal body representation of the contralateral area. Although slight regional variations in the density of labelled cells were apparent, no subzones bare of callosal labelling were observed in SIV. In both SII and SIV, callosal neurons were concentrated mainly in layer III, but a significant number was also evident in the infragranular layers. After HRP injections in the digit zone of SII or SIV, labelled cell bodies were also observed in heterotopic areas of the contralateral hemisphere. Most of these neurons were clustered in the medial bank of the coronal sulcus and in two other heterotopic cortical regions lying, respectively, in the anterior suprasylvian sulcus and in the lateral branch of the ansate sulcus. Some callosal cells interconnecting SII and SIV were also labelled. The results show that the distal forelimb zones in SII and SIV are callosally connected with the respective homotopic zones and with several somatosensory fields located heterotopically in the contralateral hemisphere.
GABA‐immunoreactive neurons and terminals in the lateral cervical nucleus of the cynomolgus monkey
Authors: Broman Jonas , Blomqvist Anders 
Published: January 2005

AbstractAn antiserum against the inhibitory transmitter substance γ‐aminobutyric acid (GABA) was used to investigate the distribution of GABAergic nerve terminals and cell bodies in the lateral cervical nucleus (LCN) of the cynomolgus monkey. Light microscopic immunohistochemistry demonstrated GABA‐immunoreactive puncta, suggestive of nerve terminals, scattered throughout the LCN. The terminal‐like profiles are often present along the somata of unlabeled neurons, but most are located in the neuropil. GABA‐immunoreactive neurons are present in the LCN, but constitute a very small number of the LCN neurons. Electron microscopy showed that the GABA‐positive neurons are small with a relatively large nucleus. They are contacted by few somatic boutons. Numerous GABA‐immunoreactive terminals containing densely packed round to oval synaptic vesicles were also found. Most GABA‐positive terminals make synaptic contact with dendrites, but synapses with cell bodies are also present. Synaptic contacts between labeled and unlabeled terminals were not observed. Some GABA‐positive terminals make contact with GABA‐positive neurons.The present findings suggest that GABA is a major inhibitory transmitter substance in the LCN of the monkey. However, in comparison with other somatosensory relay nuclei, there are few GABA‐immunoreactive neurons in the LCN. This may imply tha the GABA‐positive neurons branch extensively in the LCN or that an extrinsic source of GABAergic input exists.
Neurofilament phosphorylation in neuronal perikarya following axotomy: A study of rat spinal cord with ventral and dorsal root transection
Authors: Mansour H. , Bignami A. , Labkovsky B. , Dahl D. 
Published: January 2005

AbstractRat spinal cord was stained by indirect immunofluorescence with 11 neurofilament monoclonal antibodies that recognize phosphorylated epitopes. All monoclonals were axon‐specific in this location. The large motoneurons containing bundles of neurofilaments did not stain and the pattern remained unchanged after transection of the sciatic nerve in the thigh. With nine monoclonals, stained motoneurons were observed in the ventral horns 3 days, 5 days, 1 week, and 2 weeks after transection of the ventral roots close to the spinal cord. The abnormal motoneurons were typically scattered among normal (i.e., nonstained) cells. Even in animals showing the most severe reaction, the whole motoneuron population at the site of rhizotomy was not affected, stained and nonstained perikarya often coexisting side by side. Stained motoneurons were no longer observed 3 weeks after ventral root transection. Changes in neuronal immunoreactivity were also observed after dorsal root transection. However, a different population was affected, i.e., middle‐sized neurons in dorsal horns and at the base of ventral horns. With two monoclonals (A9 and D21), cell bodies remained negative following all operations. It is concluded that axotomy in proximity of the cell body may induce certain neurofilament phosphorylation events in motor neuron perikarya, whereas other phosphorylation events remain confined to the axons under these experimental conditions. The absence of changes after transection of the sciatic nerve in the thigh suggests that neurofilament phosphorylation is a reaction to cell injury rather than a cellular event related to nerve regeneration.
Microscopic and biochemical characterization of lectin binding sites in the cephalopod retina
Authors: Taba Ali , Quezada Beatrice H. , Robles Laura J. 
Published: January 2005

AbstractUsing light and electron microscope cytochemistry and lectin blotting techniques, we have shown that the lectins concanavalin A (Con A), Ricinus communis agglutinin (RCA), and peanut agglutinin (PNA) bind to specific glycoconjugants in the adult cephalopod retina. For light microscope lectin cytochemistry, aldehyde‐fixed, frozen, or Araldite‐embedded, etched sections of cephalopod retinas were incubated with FITC‐ or TRITC‐conjugated lectins and examined by using epifluorescence microscopy. Con A labeled structures in the entire retina including the inner limiting membrane (ILM), rhabdomeric membranes, interphotoreceptor matrix (IPM), and structures in the photoreceptor inner segments. RCA labeling was similar to that of Con A except that there was a decrease in the staining of the rhabdom tips near the ILM. PNA labeled only the interphotoreceptor matrix between apposing rhabdomeres. The intensity of staining of the IPM by PNA also decreased or was absent toward the rhabdom tips. None of the lectins labeled the myeloid bodies located in the photoreceptor inner segments. Electron microscope (EM) lectin cytochemistry was performed on aldehyde‐fixed, LR White–embedded tissue or on Araldite‐embedded, periodate‐etched sections by using gold‐conjugated lectins. EM results confirmed the observations made by light microscopy. Lectin blots with a retinal extract or light‐sensitive membrane fraction revealed a variety of protein bands labeled by all three lectins. Con A and RCA labeled opsin and its aggregates whereas PNA did not. None of the lectins labeled retinochrome.The labeling of the cephalopod IPM by PNA suggests a structural similarity between the IPM of vertebrates and invertebrates. In other studies, we have demonstrated the presence of a retinoid binding protein in the IPM of cephalopods. Thus, cephalopods may serve as a model for further investigations on the structure and function of the IPM and its role in the vitamin A cycle of the retina.
On the asymmetry of the primary branching of vagal sensory axons: Possible role of the supporting tissue
Authors: Serra Mariana , Alvarez Jaime 
Published: January 2005

AbstractCentral and peripheral nonmedullated processes of vagal nodosal neurons of the cat were studied in normal nerves and after regeneration along their anatomical course and along the hypoglossal nerve. Nonmedullated fibers above the ganglion and in the root had comparable sizes (approximately 0.37 μm2) and caliber distribution. Below the ganglion, the cross‐sectional area increased to 1.0 μm2. In axons of equal caliber, supranodosal and radicular fibers had similar microtubular densities while infranodosal fibers had two‐ to threefold that of the former. Regenerated fibers were studied after a recovery period of 6–9 months. Regrown axons were smaller than their parent axons; in turn, these were smaller than normal axons. This holds for central and peripheral nodosal branches, for homologous and heterologous regeneration. Regrown peripheral branches, either along their anatomical pathway or along the hypoglossal nerve, showed no change in microtubular density. Central branches exhibited their characteristic microtubular content when they regenerated along their anatomical course, but when regrowth took place along the hypoglossal nerve, the original low microtubular content of these branches increased to match the high content of peripheral fibers; parent central axons also shifted their microtubular content toward the pattern of peripheral fibers. We propose that the supporting tissue participates in specifying the organization of axonal microtubules.