Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Silver-stained synaptonemal complexes in surface-spread pachytene nuclei from a man, heterozygous for a reciprocal translocation, were analysed by electron microscopy. Contrary to the classically expected cross-shaped configuration, extensive non-homologous pairings were observed with asymmetrical association in the lateral elements of the non-homologous arms of the quadrivalents. A possible role of the heterosynapsis in reproductive failure is discussed.
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PMID:Synaptonemal complex analysis in a human male carrier of a 4;6 translocation: heterosynapsis without previous homosynapsis. 199 82

Light and electron microscope studies of the terminal fields of the spinal afferents ascending in the ventrolateral quadrant of the spinal cord to the periaqueductal gray matter (PAG) were carried out using silver degeneration techniques and anterograde WGA-HRP transport. At all mesencephalic levels the terminal degeneration and the labelling of the spinal fibres to the PAG were fairly dense, mainly concentrated in the outer part of the annular ring. At the electron microscope, the spinal nerve terminals were found ending almost exclusively in the neuropil, impinging on small dendritic profiles. The majority of these synaptic contacts were of the asymmetrical type and contained a prevalence of round vesicles. This study provides an accurate representation of the terminal domain of the spino-PAG afferents and gives the conclusive anatomical evidence that the fibres ascending in the ventro-lateral funiculus of the spinal cord do not simply pass through the PAG, but actually terminate in it, synapsing in the neuropil.
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PMID:The spinal terminals into the midbrain periaqueductal gray of the rat. A light and electron microscope study of the projections ascending via the ventro-lateral funiculus. 223 Jan 4

The spinal cords of 10 cases of motor neuron disease were compared with those of six age-matched controls using myelin and silver impregnation methods, and the Marchi reaction for myelin degradation products. These studies revealed striking asymmetry in involvement of the lateral and anterior corticospinal tracts, without concordance in the pattern of involvement of these crossed and uncrossed corticospinal pathways. In addition there was prominent involvement of the posterior and anterior spinocerebellar tracts, but less marked abnormality was seen in the reticulospinal pathways. These findings highlight the asymmetrical involvement of the upper and lower motor neuron components of the motor system that is a characteristic feature of the disease, and demonstrate that involvement of the spinocerebellar system is a frequent finding.
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PMID:Selective and asymmetric vulnerability of corticospinal and spinocerebellar tracts in motor neuron disease. 316 41

Silver-stained synaptonemal complexes (SCs) in surface-spread pachytene nuclei from a boar, heterozygous for a reciprocal translocation, were analysed by electron microscopy. In such heterozygotes, cross-shaped quadrivalent configurations are expected to form in order to maximize homologous pairing. Contrary to the classical, expected cross-shaped configuration, heterosynapsis was often observed, with asymmetrical association in the lateral elements of the non-homologous partners of the quadrivalents. This heterosynapsis is assumed to be a mechanism preventing spermatocyte loss, but inducing a secondary segregational type of impairment of fertility due to foetal wastage leading to reduced prolificacy.
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PMID:Heterosynapsis in a heterozygous fertile boar carrier of a 3;7 translocation. 319 94

The reciprocal connections between the claustrum and the auditory cortical fields AI, AII and Ep were investigated by means of Nauta and Fink-Heimer selective silver impregnation procedures, electron microscopic identification of degenerated axons and synaptic boutons, and with the Mesulam horseradish peroxidase retrograde tracing technique. The course and termination of degenerating corticoclaustral axons were investigated following circumscript lesions of the AI, AII and Ep areas in 19 cats. The greatest amount of degeneration debris was observed following destruction of the AII area. The central third of the claustrum (stereotaxic level A13-A15) is filled with degenerating terminals (d. t.), with greatest concentration in the lateral wedge of the nucleus, and along its inferolateral border. Rostrally and caudally the density of degeneration diminishes but scattered d. t. were observed up to the rostral pole, and a moderate number - up to the caudal pole of the claustrum. Slightly lesser amount of d. t. was observed following Ep destruction. The caudal portion of the claustrum is filled with d. t. In the central third the degeneration field occupies mainly the ventrolateral zone of the nucleus. The rostral pole of the claustrum is free of degeneration. The projection from the AI field is considerably more moderate, and is diffusely organized. A substantial number of d. t. is encountered only in the lateral parts of the central claustral third. The crossed corticoclaustral connections mirror the ipsilateral ones but are far more modest. The AII area projects mainly to the central claustral third, the Ep area--to the caudal third. The projection of the AI area to the contralateral claustrum is very weak. The electron microscopic examination of the claustrum following auditory cortex destruction in 9 cats revealed an appreciable number of degenerating synaptic boutons. They undergo dark and more rarely light degenerative changes. The cortical terminals are classified in two types: "small round" (SR), comprising approximately 70 to 75% of the corticoclaustral boutons, and "large round" (LR)-25-30%, resp. The SR boutons measure 0.6-1.2 micron, contain tightly packed round synaptic vesicles (380-420 A), and form asymmetrical axodendritic contacts. The LR boutons measure 1-2.5 microns, contain round vesicles (400-500 A) and form asymmetrical axodendritic and (far more rarely) axosomatic contacts. The claustrocortical connection was investigated in 13 cats with selective injections of 30% HRP in the three subdivisions of the auditory cortex.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Reciprocal connections between the claustrum and the auditory cortical fields in the cat. An experimental study using light- and electron microscopic anterograde degeneration methods, and the horseradish peroxidase retrograde axonal transport. 341 13

The three-dimensional morphology of the surface of myelinated nerve fibres in the mouse sciatic nerve was studied by scanning electron microscopy after combined potassium hydroxide treatment and collagenase digestion (to remove the surrounding collagen fibrils and basal laminae from nerve fibres) as well as by transmission electron microscopy. The myelinated nerve fibre appeared as a long cylinder with sporadic annular constrictions corresponding to the nodes of Ranvier. Slight swellings of the surface due to Schwann cell nuclei were usually found at the middle of each internode. The surface of the nerve fibre clearly exhibited a network of bulges, which consisted of longitudinal bands extending from the nuclear swelling to the nodes of Ranvier through the internode, and transverse trabeculae bridging between these longitudinal bands. These bulges on the surface of nerve fibres were the site of the retained Schwann cell cytoplasm external to the myelin lamellae. These cytoplasmic networks on myelinated fibres presumably corresponded to the networks described by Cajal following silver impregnation. In addition, other thin elevations and focal round swellings were also found associated with these longitudinal bands and transverse trabeculae. These networks of Schwann cell cytoplasm are considered to be cytoplasmic channels for nutrition. The two apposing paranodal bulbs of nodes of Ranvier were often asymmetrical in their structure. The networks of the paranodal region were more complicated than those in the internode. The networks of Schwann cell cytoplasm converged into a continuous circumferential collar toward the node, which in turn gave rise to finger-like projections into the nodal gap.
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PMID:Scanning electron microscopic studies of the myelinated nerve fibres of the mouse sciatic nerve with special reference to the Schwann cell cytoplasmic network external to the myelin sheath. 345 Jul 86

Chinese hamster metaphase chromosomes were labeled by nick-translation, which involved pretreatment of metaphase chromosomes with low levels of DNase I followed by incubation with DNA polymerase I and radioactively labeled nucleotides. The labeled DNA was located on nuclease-hypersensitive regions of the chromosomes, as suggested by the following observations. (i) The labeled DNA was hypersensitive to the subsequent DNase I digestion. (ii) The labeled DNA contained no nucleosomes. DNA reassociation kinetic analysis suggested that the labeled DNA was enriched in repetitive DNA sequences. Base composition analyses showed that the labeled DNA was highly enriched in guanine and adenine residues, suggesting that the nick-translation reaction was asymmetrical and the strand enriched in purine was preferentially translated. Autoradiographic analysis revealed that the label was distributed on every chromosome, but there was a lower grain density on the Y chromosome, which is heterochromatic and exhibits a relatively low level of gene activity. The locations of silver grains on the Y chromosomes were generally consistent with that revealed by the in situ hybridization using [3H]cDNA synthesized from the total Chinese hamster messenger RNA. These observations suggest that a specific subset of genomic DNA on active chromatin is the preferred site of the nick-translation.
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PMID:Nick-translation of metaphase chromosomes: in vitro labeling of nuclease-hypersensitive regions in chromosomes. 385 36

Morphometric analysis of the symmetry of middle and large ganglionic cells was performed on silver-impregnated retinal wholemounts of the frog. The nucleolus and the axis passing through the nucleolus in direction to optic disk were chosen as elements of symmetry characterizing the radial symmetry and bilateral one, respectively. It is demonstrated that the dendritic ramification angles of all cell types are smaller than 360 degrees and the angles of middle-type-GC are smaller than 180 degrees. In addition, their somata do not lie in the centre of the dendritic field, thus ganglionic cells have no radial symmetry. Directions of the axon and dendrites are opposite each other in the most of ganglionic cells, the terminals of dendrites being oriented from retinal centre to periphery in all quadrants of the retinal map. For estimation of bilateral symmetry the distance from the greatest remoted dendritic terminals to cell axis on the left and on the right from it was measured. Besides, the numbers of ramification knots and basal dendrites were counted. Most of ganglionic cells are asymmetrical in 2-3 mentioned structural parameters. Thus, the asymmetry in the structure of frog retinal neurons is rather norm than exception. Correlation between the asymmetry in ganglionic cell structure and functional asymmetry of their receptive fields is discussed.
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PMID:[Asymmetry in the structure of average and large neurons of the ganglion layer of the frog retina]. 404 42

Serotonergic axonal endings in layers I and II of the dorsal horn of the medulla were identified by autoradiography. In adult cats, pretreated with a monoamine oxidase inhibitor, tritiated serotonin ([3H]5-HT) was topically applied onto the surface of the caudal medulla. Light autoradiographs from 1 micrometer sections demonstrated silver grains in both layers I and II. In EM autoradiographs, two categories of axonal endings were labeled by [3H]5-HT uptake: dome-shaped endings which form a single synapse and scalloped endings which form multiple synapses. Each category was further divided into several types based on morphological criteria. The [3H]5-HT-labeled endings synapse primarily on small caliber dendritic shafts and spines, with the dome-shaped endings forming both symmetrical and asymmetrical synapses and the scalloped endings forming only asymmetrical synapses. Dome-shaped endings were most common and two types were found in layers I and II while a third type was found only in layer II. Layer I contained a single type of scalloped ending while layer II contained three types of scalloped endings. In a series of experiments designed to provide another approach to identifying serotonergic endings, 5,6-dihydroxytryptamine, a serotonin neurotoxin, was either topically applied onto the caudal medulla or injected into the fourth ventricle. Following treatment with the neurotoxin, blackened degenerating dome-shaped and scalloped endings similar to those labeled in the [3H]5-HT uptake experiments were found in layers I and II. The presence of serotonergic endings in layer I suggests that some of these endings synapse on the dendrites of layer I projection neurons where they may inhibit the output of the projection neuron directly. Serotonergic endings in layer II may modulate the activity of layer II interneurons by synapsing directly on these interneurons. The interneurons in layer II may function by mediating the transfer of inputs from primary endings in these layers to layer I projection neurons.
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PMID:Ultrastructural characterization of axonal endings in the substantia gelatinosa which take up [3H]serotonin. 615 52

In an attempt to evaluate the cellular organization and efferent projections of the nucleus tegmenti pedunculopontinus pars compacta, several experiments were performed in the rat. From measurements of neurons in the nucleus tegmenti pedunculopontinus pars compacta in Nissl-stained sections, the nucleus was observed to contain many large neurons which made it possible to demarcate this nucleus from surrounding pontomesencephalic reticular formation. Two other neuronal populations, medium and small neurons, were also seen in the nucleus tegmenti pedunculopontinus pars compacta. Detailed measurements showed that 90% by volume of all neurons in the nucleus tegmenti pedunculopontinus pars compacta were large and medium-sized neurons. After injections of [3]leucine into the nucleus tegmenti pedunculopontinus pars compacta, transported label was observed in dorsally and ventrally coursing ascending fibers. The dorsally coursing fibers entered the centrolateral nucleus and centre median-parafascicular complex of the thalamus. The ventrally coursing fibers produced accumulation of silver grains in the ventral tegmental area, substantia nigra pars compacta, subthalamic nucleus, zona incerta and lateral hypothalamus. Crossed fibers of the nucleus tegmenti pedunculopontinus pars compacta were observed sparsely at the levels of the thalamus and posterior commissure, and to a greater degree through the supraoptic commissure of Meynert. Much less anterograde labeling was seen in the equivalent terminal sites on the contralateral side of the brain. By electron microscopic autoradiography major terminal sites of axons of the nucleus tegmenti pedunculopontinus pars compacta were examined in rats injected with [3H]leucine in the nucleus tegmenti pedunculopontinus pars compacta and later injected with horseradish peroxidase in the striatum and pallidum. Statistical data showed preferential radiolabeling of terminals forming asymmetrical synaptic contact with dendrites in the centrolateral nucleus, centre median-parafascicular complex and subthalamic nucleus. Apparent terminations in the substantia nigra pars compacta proposed in earlier studies and shown in the present light microscopic autoradiograms were not supported by this ultrastructural analysis. Several radiolabeled terminals of the asymmetrical type contacting horseradish peroxidase labeled dendrites in the thalamus confirmed direct input from the nucleus tegmenti pedunculopontinus pars compacta to the thalamostriate projection neurons. [3H]choline injections into the thalamus and subthalamic nucleus produced retrograde perikaryal labeling of large neurons in the nucleus tegmenti pedunculopontinus pars compacta.
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PMID:Organization and efferent projections of nucleus tegmenti pedunculopontinus pars compacta with special reference to its cholinergic aspects. 673 60


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