bluuebunny/crossref_metadata_2025_split huggingface dataset:
Formation of arynezirconocenes from substituted diaryl bis (t‐butylcyclopentadienyl) zirconium: application to the synthesis of new functionalized ortho‐dichalcogenobenzene compounds
Authors: Bodiguel J , Meunier P , Gautheron B 
Published: December 2004

AbstractThe para‐substituted diphenylzirconocenes [(t‐BuCp)2Zr(p‐C6H4R)2; R = Br, NMe2] (A) were easily obtained from the reaction of the appropriate organolithium reagent with bis(t‐butylcyclopentadienyl)zirconium dichloride. Elimination of bromobenzene or N,N‐dimethylaminobenzene from A by slight heating led to arynezirconocenes into which were inserted two equivalents of elementary chalcogens. As a result dichalcogenated zirconacycles [(t‐BuCp)2ZrY2C6H3R; Y = S, Se] (B) were obtained. Complexes B constitute useful potential synthons in organic synthesis and a large family of new functionalized dichalcogenated benzenic compounds was prepared by reacting electrophiles.The structure of complexes B as well as related benzenic derivatives has been confirmed by microanalysis, 1H NMR and mass spectrometry.
Identification of microglia in light and electron microscopy
Authors: Mori Shiro , Leblond C. P. 
Published: December 2004

AbstractThe corpus callosum of 60–80 gm male rats was processed by the weak silver carbonate method of del Rio‐Hortega for the detection of microglia in the light microscope. Because of the opacity of the metal stain taken up by these cells, they could be recognized in the electron microscope. The characteristic features of microglia were thus found to be a small nucleus in which dark chromatin contrasts with light nucleoplasm, and a cytoplasm containing dense bodies (presumed to be lysosomes) and poor in endoplasmic reticulum. After gaining experience with microglia in the electron microscope, it became possible to recognize their features in 0.5–1 μ thick toluidine blue stained Epon sections examined in the light microscope.In the electron microscope, some microglia are found within expansions of the basement membrane of capillaries (pericytal microglia); they usually have little cytoplasm, few dense bodies and few processes. There is evidence that these cells can break out of their basement membrane enclosure and enter the brain tissue proper. There, they scatter singly between other cells and fibers. These cells (interstitial microglia) send of long processes. They may contain numerous dense bodies and be surrounded by irregular spaces (suggesting the existence of surface activity). These observations support the classical view of microglia as brain macrophages.Microglia constitute 5.5% of the glial population of the corpus callosum. After injection of 3H‐thymidine and radioautography in the light or electron microscope, none showed labeling. Hence, it is presumed that microglia do not proliferate under normal conditions.
Cell changes in sensory ganglia following proximal and disal nerve section in the monkey
Authors: Carmel Peter W. , Stein Bennett M. 
Published: December 2004

AbstractGanglion cell changes were studied in 25 monkeys following systematic section of spinal and cranial sensory nerves proximal or distal to the ganglion. Ganglion cells were studied in Nissl preparations while central degeneration was studied in Nauta‐Gygax stained sections. Morphological characteristics of normal ganglia were studied in unoperated controls.In normal ganglia three categories of cells were identified: (1) A predominant largecelled group (ranging from 20 to 100 μ), (2) small dark cells, and (3) a small number of “atypical” cells.Division of nerves proximal to ganglia produced no cellular changes in most cases; changes attributed to relative ischemia occurred in a few ganglia. Centrally projecting fibers of sectioned nerves were degenerated.Division of sensory nerves distal to ganglia produced profuse chromatolytic changes in cells of all sizes and types within ganglia but no central degeneration. Cervical section of the vagus produced chromatolytic cell changes in the inferior ganglion and a small portion of the superior ganglion unrelated to the auricular nerve. Section of the facial nerve distal to the geniculate ganglion produced chromatolysis in approximately half of the ganglion cells. An accessory trigeminal ganglion, composed of cells of autonomic type, was found distal to the trigeminal ganglion in association with the third division of the nerve.Severance of nerve fibers distal to sensory ganglia eliminates peripheral neurotrophic influences necessary for the growth and maintenance of the ganglion cell. It is postulated that the integrity of this influence is sufficient to sustain sensory ganglion cells after their central processes have been sectioned.
The fine morphology of the sensory receptor organs in the auricle of the rat
Authors: Cauna Nikolajs 
Published: December 2004

AbstractThe fine structure, distribution of cholinesterase activity and microtopography of the sensory receptor organs of the rat's auricle were studied in six animals. It was found that the skin of the auricle consisted of minute but well defined receptor territories each supplied by a morphologically distinct nerve ending.The horizontal endings, derived from non‐myelinated nerve fibers, supplied linear skin areas covering the intervals between the hair orifices and sending fine twigs into the epidermis. They had the simplest morphology and showed no cholinesterase activity.The papillary endings were restricted to the immediate vicinity of the hair orifices. They exhibited butyrocholinesterase activity and showed a typical fine morphology. The expanded axon terminals were filled with mitochondria and enclosed by Schwann cells of some complexity.The nerve endings of the fine hairs were derived from myelinated axons. The endings showed acetyl‐ and butyrocholinesterase activity. The terminal fibers ended in spindles that were arranged longitudinally in a semicircle around the epithelial root sheath of the hair forming a single layer between the orifices of the sebaceous glands and the base of the hair follicle. The endings were characterized by the accumulation of mitochondria and microvesicles in the terminal spindles and by the high pinocytotic activity in the associated Schwann cell processes.The deep tissues contained at least one kind of simple beaded nerve ending that gave a negative cholinesterase reaction.It was concluded that the morphological diversity of the sensory apparatus was adequate to account for a considerable degree of specificity or at least selectivity of its end organs.
The primary optic projections in the rabbit. An experimental degeneration study
Authors: Giolli Roland A. , Guthrie Mary D. 
Published: December 2004

AbstractThe brains of ten rabbits (4 pigmented and 6 albino) sacrificed 6–21 days after unilateral ocular enucleation were prepared by Nauta and Nissl methods and used to study the projection and terminal destribution of degenerating optic axons. The retina is bilaterally represented in the alpha sectors of both ventral and dorsal lateral geniculate nuclei (LGv and LGd), in n. tractus opticus (NTO), in the dorsolateral portions of nn. praetectalis anterior (NPA) and posterior (NPP), and in the superior colliculus (SC). The retina is unilaterally represented in the contralateral terminal accessory optic nuclei.The mode of termination of crossed and uncrossed retinal projections endows the LGd with a concealed laminar organization. Four laminae are recognized and numbered consecutively from lateral to medial. Lamina one is extensive and formed entirely of crossed retinal input. The remaining three laminae occupy the medial zone of the LGd. Of these, laminae two and four are innervated predommantly by the ipsilateral retina while lamina three is supplied mainly by the contralateral retina. Uncrossed retinal innervations of LGv, NTO, NPA, NPP and SC are scant and overlapped entirely by crossed retinal inputs. Chiasmal decussation of the optic nerve is 90–95% complete with the uncrossed component, and specifically the uncrossed retino‐LGd and ‐SC projections, being larger in pigmented as compared with albino rabbits.
Monoamine‐containing neurons in the central nervous system and peripheral nerves of the leech, Hirudo medicinalis
Authors: Rude Sonia 
Published: December 2004

AbstractThe 34 ganglia of the leech (Hirudo medicinalis) central nervous system together with their connectives and roots have been studied by means of the fluorescence histochemical technique for monoamines.More than half the ganglia of the central nervous system possess the same number of monoamine‐containing neurons in a fixed location. These identical ganglia consist of seven yellow fluorescent monoamine‐containing neuron perikarya located within the ganglia and a pair of blue‐green fluorescent monoamine‐containing perikarya located outside the ganglia in the anterior roots. A neuropile consisting of a dense network of yellow and blue‐green fluorescent varicose processes, several smooth blue‐green fluorescent processes and occasional smooth yellow fluorescent processes is present in the ganglia. Smooth and varicose yellow and blue‐green fluorescent processes are found in the connectives and roots of the ganglia. The intraneuronal distribution of fluorescence within the nine monoamine‐containing neurons of identical ganglia is described.The monoamine‐containing neurons of the remaining ganglia of the central nervous system are described. These ganglia are shown to vary only slightly from the pattern of identical ganglia.
Identification of beta fibers at spindle entry
Authors: Berndt J. M. , Oswaldo‐Cruz E. , Rocha‐Miranda C. E. 
Published: December 2004

AbstractUsing a silver impregnation technique, mainly in teased material, the pattern of muscle spindle motor innervation was compared between reptilian and marsupial material. It was concluded that, although rare, beta fibers (motor nerve fibers which innervate intra‐ and extrafusal muscle fibers) can also be detected at spindle entry in reptiles and in mammals, but that the occurrence is higher in reptilian material.
Cytoarchitecture of the cochlear nuclei in the cat
Authors: Osen Kirsten Kjelsberg 
Published: December 2004

AbstractThe microscopical structure of the cat cochlear nuclei was studied in Nissl preparations in order to get a suitable map for further experimental investigations. The neurons of the entire nuclear complex were classified into nine different types according to their microscopical appearance. Seven of the nine types, viz., the large spherical cells, small spherical cells, octopus cells, globular cells, pyramidal cells, giant cells, and granular cells, seem to constitute rather uniform cell groups, while the remaining types, viz., the multipolar cells and small cells, seem to be rather heteromorphic. On the basis of the distribution of these cell types the nuclear complex was divided into a corresponding number of cell areas which proved to be partly overlapping. This principle of parcellation led to a certain simplification of the previously proposed schemes of the organization of the cochlear nuclei based on cellular characteristics.
Efferent projections of the anterior olfactory nucleus
Authors: Ferrer Nathaniel G. 
Published: December 2004

AbstractThe efferent projection fibers from the rostral and the medial segments of the anterior olfactory nucleus have been studied using the Nauta or the Fink modification of the Nauta method for degenrating axons. Lesions were suitably placed by electrocoagulation. From the rostral segment of the anterior olfactory nucleus efferent fibers by way of the bulbar part of the anterior commissure were traced to the internal granular and the mitral cell layer of the normal side. Preterminal and terminal degeneration were traced by way of the homolateral lateral olfactory tract and these fibers ended in the lateral two‐thirds of the olfactory tubercle, the prepiriform, the piriform and the periamygdalar cortices and into the corticomedial segment of the amygdaloid complex. Degenerating fibers were also noted in the dorsomedial nucleus, the lateral habenular nucleus, the lateral hypothalamic area and in the supraoptic area of the same side where the lesion was made. In animals where the lesion was placed in the medial segment of the anterior olfactory nucleus the same fiber distribution was observed as reported when the lesion was placed in the rostral segment of the anterior olfactory nucleus. However, other areas were observed receiving fibers from the medial segment of the nucleus. These areas were the basolateral segment of the amygdaloid complex and the mammillary areas.
Development of the blood vessels and extracellular spaces during postnatal maturation of rat cerebral cortex
Authors: Caley David W. , Maxwell David S. 
Published: December 2004

AbstractAs part of a larger study of the development of postnatal rat cerebral cortex, this report deals with the maturation of the cortex as a tissue from birth to twenty‐one days of age. The changes in the numerical density of cells and blood vessels and the thickness of the cortex at successive ages were followed on light micrographs, and both were related to the ultrastructural observations on routine electron microscopic preparations. The maturation of the cortex is divided into two periods: The first ten days during which the growth to adult dimensions occurs and few patent blood vessels but large extracellular spaces are to be found, and the second ten days in which the majority of the vessels develop patent lumina, the perivascular sheath of astrocyte end‐feet develops, and the large extracellular spaces disappear concomitant with the maturation of the neuropil.The blood vessels appear to develop during the first ten days as solid cords of mesodermal elements which form a network of primordial vessels with thick walls and slit‐like lumina containing a flocculent material. The formation of a blood filled, patent lumen apparently occurs synchronously over a brief period of time for the majority of the vessels during the early part of the second ten‐day period. The basal lamina is ill‐defined initially but takes on mature appearance parallel with the development of the perivascular glial sheath.The volume of the extracellular space was found to be largest during the phase of rapid growth of axons and dendrites when few patent vessels exist. The disappearance of these large extracellular spaces during maturation of the blood vessels and neuropil is discussed in terms of the possible artifactitious nature of these spaces in both immature and mature cortex.
Thalamo‐cortical organization of the visual system in the cat
Authors: Niimi Kahee , Sprague James M. 
Published: December 2004

AbstractThalamo‐cortical relationships in the visual system of the cat were studied by the method of retrograde degeneration. Localized lesions limited to area 17 result in degeneration only in the dorsolateral geniculate body; cell changes are marked in 3 laminae (A, A1, B), mild in nucleus interlaminaris centralis and minimal in nucleus interlaminaris medialis. Lesions limited to areas 18 and 19 are followed by marked degeneration in the medial interlaminar nucleus, mild in the other laminae; in addition, the lateral part of the posterior thalamic nucleus (ventral or inferior pulvinar) is also atrophied. Following large striate lesions which marginally involved areas 18 and 19, there is also mild, localozed degeneration in the anteroventral and reticular thalamic nuclei. Whin cortical lesions are limited to the convexity of the suprasylvian gyri, degeneration is present in the lateral aspect of laminae A, A1, B and nucleus interlaminaris centralis and in the medial part of the posterior nucleus, in addition to lateral dorsal, lateral posterior and pulvinar nuclei. Lesions in the ectosylvian gyri result in slight but definite degeneration in the lateral part of lamina A of the dorsal lateral geniculate, but nothing in the posterior nucleus. The geniculate projections to areas 17, 18 and 19, to the suprasylvian and ectosylvian gyri all show a rostrocaudal organization. The geniculostriate projection is also topographically organized in a mediolateral manner.Thus, the geniculocortical projection in the cat is not striate specific but spreads over the occipito‐temporal cortex at least as far as the acoustic areas of the ectosylvian gyri. In this species the dorsal lateral geniculate body is not a unitary structure but is a complex of nuclei, all of which receive retinal fibers, and the cortical projections of which overlap those of the posterior, lateral dorsal, lateral posterior, pulvinar, medial geniculate, reticular and anterior thalamic nuclei.
The amygdala of the box turtle, Terrapene c. carolina
Authors: Carey Joshua H. 
Published: December 2004

AbstractThe amygdala of the box turtle lies beneath the posterior hypopallial ridge. Three nuclear groups may be distinguished in it: (1) the anterior amygdaloid area, (2) the basolateral group and (3) the corticomedial group. The anterior amygdaloid area shows no subdivisions; its location ventral and ventromedial to the caudal part of the small‐celled portion of the piriform area is evident. The basolateral group is subdivided into lateral and basal amygdaloid nuclei. The interconnections of this group through the anterior commissure with the comparable area in the opposite amygdala and with the corticomedial group indicate that it is functionally a vicarious cortex. The corticomedial group is divisible into medial and cortical amygdaloid nuclei. The medial nucleus is poorly defined. The cortical nucleus is bounded by the medial amygdaloid nucleus on the medial side and the ventral border of the piriform cortex laterally, and is comparable to the cortical amygdaloid nucleus of higher vertebrates.The lateral olfactory tract arises from mitral cells of the olfactory bulb and accessory olfactory bulb and neurons of the anterior olfactory nucleus. The lateral part of the anterior olfactory nucleus, the lateral and the intermediate parts of the tuberculum olfactorium and the small‐celled part of the piriform cortex contribute to and receive fibers from the lateral olfactory tract. The lateral olfactory tract sends fibers to the anterior amygdaloid area and the corticomedial group. The lateral corticohabenular tract has an anterior and a posterior division. The anterior division arises from cells of the nucleus of the lateral olfactory tract and the lateroventral portion of the piriform cortex. It is joined by those fascicles arising in the corticomedial group and designated as the amygdalohabenular tract. This tract crosses in the habenular commissure and retraces its course to enter the corticomedial amygdaloid nuclear group on the side opposite its origin. The basolateral group is interconnected through the anterior commissure.The stria terminalis contains three components which interconnect the corticomedial amygdaloid nuclear group with the septum, the preoptic area and the hypothalamus. The supracommissural and the intracommissural components relate the cortical and the medial nuclei to the septum, the preoptic area and the hypothalamus of the same side. The infracommissural component interconnects the cortical and the medial amygdaloid nuclei with the septum, the preoptic area and the hypothalamus of the same and the opposite side.The dorsal and the ventral olfactory projection tracts arise from the corticomedial amygdaloid nuclear group. They terminate in the preoptic area and anterior hypothalamus.
Viscerotopic organization of the vagus
Authors: Kerr F. W. L. , Hendler N. , Bowron P. 
Published: December 2004

AbstractThe represetation in the vagal rootlets of visceral efferent fibers to the heart and to the smooth muscle of the bronchi, esophagus and duodenum has been investigated in cats whose vagus had undergone chronic selective rhizotomies.Cardiodecelerator fibers are well known to be the caudal rootlets and this was confirmed. Motor fibers to the esophagus and to the bronchi are present at all levels, while effernts to the duodenum are limited to the caudal fibers of the root complex.Because the vagal efferents emerge in the same plane as their somata, these data have been extrapolated to the medullary centers.
The axonal pathways of spinal neurons in the cat
Authors: Matsushita Matsuo 
Published: December 2004

AbstractThe axonal pathways of spinal neurons were studied in the cat using Ramón y Cajal's silver method.The cells of the ventral group of the nucleus supraspinalis contribute to the ventral roots of C1 and the cells of the dorsal group send their axons to the contralateral ventral funiculus. The cells of lamina VII send their axons to the ipsilateral lateral or ventrolateral funiculus. The subnucleus ventralis of the nucleus medullae oblongatae centralis sends axons to the lateral funiculus or to the ventral roots of C1. The cells of lamina V send their axons to the lateral funiculus and the contralateral ventral funiculus. The cells of lamina VII send their axons to the ipsilateral lateral funiculus and to the contralateral ventral funiculus. Numbers of spinal border cells were were observed in lamina IX at the level of the cervical and lumbar enlargement. It was found that the cell groups which were classified cytoarchitectonically contained numbers of different types of cells as judged by their axonal pathways.
The lateral cervical nucleus of cat, dog and man
Authors: Truex R. C. , Taylor M. J. , Smythe M. Q. , Gildenberg P. L. 
Published: December 2004

AbstractThis nucleus was identified in four cats, four dogs and nine human spinal cords, but was not identifiable in seven other human specimens. In all three species the nucleus extends rostrally into the lower third of the medulla. Cell measurements of the perikarya yielded a mean diameter of 34.1 μ in the dog, 26.7 μ in the cat, and 15.7 μ in man. Nuclear diameters as well as the nucleus‐cytoplasm and volume ratios were determined. The lateral cervical nucleus is considered to be rudimentary in man and was a well‐defined structure in only 2 of 16 specimens. In one of these two cases a total of 5173 cells were counted in the nuclei of both sides at the C1 and medullary levels. The pertinence of these observations to the preservation of tactile sensation after injury of the dorsal columns in man, is discussed.
Postnatal maturation in the cochlea of the cat
Authors: Pujol Remy , Marty Robert 
Published: December 2004

AbstractAt birth, the cochlea of the cat, though generally developed, is still immature. Maturation of the organ of Corti begins at the base and gradually reaches the apex. In two weeks the process is complete. The most significant morphological criteria of the epithelial maturation are the formation of the tunnel of Corti and of the space of Nuel, the lengthening of the outer hair cells and the freeing of the internal spiral sulcus. On the third day after birth, the appearance of these criteria at the level of the first coil of the lamina spiralis coincides with the general physiological awakening of the auditory systems, as testified by the recording of evoked potentials from the cerebral cortex. Since such responses can be provoked by electrical stimulation of the nerve from birth onwards, the maturation of the organ of Corti appears to be the final stage in the development of the auditory system.