47,164 research outputs found
Müller glia activation in response to inherited retinal degeneration is highly varied and disease-specific
No full textDespite different aetiologies, most inherited retinal disorders culminate in photoreceptor loss, which induces concomitant changes in the neural retina, one of the most striking being reactive gliosis by Müller cells. It is typically assumed that photoreceptor loss leads to an upregulation of glial fibrilliary acidic protein (Gfap) and other intermediate filament proteins, together with other gliosis-related changes, including loss of integrity of the outer limiting membrane (OLM) and deposition of proteoglycans. However, this is based on a mix of both injury-induced and genetic causes of photoreceptor loss. There are very few longitudinal studies of gliosis in the retina and none comparing these changes across models over time. Here, we present a comprehensive spatiotemporal assessment of features of gliosis in the degenerating murine retina that involves Müller glia. Specifically, we assessed Gfap, vimentin and chondroitin sulphate proteoglycan (CSPG) levels and outer limiting membrane (OLM) integrity over time in four murine models of inherited photoreceptor degeneration that encompass a range of disease severities (Crb1rd8/rd8, Prph2+/Δ307, Rho-/-, Pde6brd1/rd1). These features underwent very different changes, depending upon the disease-causing mutation, and that these changes are not correlated with disease severity. Intermediate filament expression did indeed increase with disease progression in Crb1rd8/rd8 and Prph2+/Δ307, but decreased in the Prph2+/Δ307 and Pde6brd1/rd1 models. CSPG deposition usually, but not always, followed the trends in intermediate filament expression. The OLM adherens junctions underwent significant remodelling in all models, but with differences in the composition of the resulting junctions; in Rho-/- mice, the adherens junctions maintained the typical rod-Müller glia interactions, while in the Pde6brd1/rd1 model they formed predominantly between Müller cells in late stage of degeneration. Together, these results show that gliosis and its associated processes are variable and disease-dependent
Müller K. V. — Heimatvertriebene Jugend
No full textCailar A. Müller K. V. — Heimatvertriebene Jugend. In: Population, 12ᵉ année, n°1, 1957. p. 172
K+ Channels of Müller Glial Cells in Retinal Disorders
No full text
Background & Objective: Müller cell is the major type of glial cell in the vertebrate retina.
Müller cells express various types of K+ channels, such as inwardly rectifying K+ (Kir) channels, big
conductance Ca2+-activated K+ (BKCa) channels, delayed rectifier K+ channels (KDR), and transient
A-type K+ channels. These K+ channels play important roles in maintaining physiological functions of
Müller cells. Under some retinal pathological conditions, the changed expression and functions of K+
channels may contribute to retinal pathogenesis.
Conclusion:
In this article, we reviewed the physiological properties of K+ channels in retinal Müller
cells and the functional changes of these channels in retinal disorders.
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Der Sprachgebrauch in den Dialektgebieten von Südost-Yorkshire und Nord-Durham /
No full textDer heutige Sprachgebrauch im südöstlichen Yorkshire, von Alfred Müller.--Der Sprachgebrauch in Nord-Durham mit Berücksichtigung von Süd-Durham und Südost-Northumberland, von K.-H. Borgis
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K(+)-evoked Müller cell depolarization generates b-wave of electroretinogram in toad retina
No full textWe tested the hypothesis that a light-evoked increase in [K+]o produces a depolarization of the Müller cell membrane, which in turn generates the electroretinogram b-wave current. Using Bufo marinus isolated retinas and K(+)-selective microelectrodes, we recorded two distinct light-evoked increases in extracellular K+ concentration: one in the inner plexiform layer and the other near the outer plexiform layer; the "distal" K+ increase was found over only 10-microns depth and had a maximum amplitude of 0.3 mM. We also recorded the electroretinogram and the light-evoked responses of rods and Müller cells. After correction for the response time of the K(+)-selective microelectrode, the waveforms of all three of these responses were almost exactly as predicted by an earlier computer simulation of the K+/Müller cell hypothesis of the b-wave by Newman and Odette [Newman, E.A. & Odette, L.L. (1984) J. Neurophysiol. 51, 164-182]. The distal K+ increase and the b-wave varied in a similar manner as a function of stimulus irradiance. Superfusion with 0.2 mM Ba2+ attenuated both the Müller cell depolarization and the b-wave by approximately 65% but had no significant effect upon the distal K+ increase. Because Ba2+ reduces K+ conductance of Müller cells, these results are very strong support of the K+/Müller cell hypothesis of the origin of the electroretinogram b-wave; the light-evoked increase in extracellular potassium concentration still is present during superfusion with Ba2+, but the K(+)-evoked Müller cell depolarization and the b-wave are decreased in amplitude because Müller cell K+ conductance is reduced
A teoria da norma de Friedrich Müller: reflexos na metódica jurídica
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina. Centro de Ciências Jurídicas. Programa de Pós-Graduação em Direito.O presente trabalho propõe-se a investigar de que forma a concepção de norma jurídica, levada a efeito pela teoria e metódica estruturantes, reflete na interpretação e na aplicação do direito. O objetivo principal é analisar de que forma a metódica estruturante se afasta dos conceitos e métodos propostos pelas escolas hermenêuticas de decisão jurídica que lhe são precedentes. O trabalho analisa as principais escolas hermenêuticas do século XIX e XX, no intuito de perquirir a específica racionalidade metodológica presentes em cada uma delas. Busca a caracterização da teoria da norma jurídica de Friedrich Müller. Disseca a relação entre direito e realidade na teoria da norma. Apresenta os conceitos de normatividade, interpretação e concretização. Avalia a estrutura da norma e as suas partes integrantes: o programa da norma (Normprogramm) e o âmbito da norma (Normbereich). Em vista da profunda ligação entre a teoria da norma e a metódica jurídica, investiga o contexto de formação da metódica estruturante. Expõe os elementos de concretização da metódica estruturante, bem como a sua função e hierarquia. Busca finalmente apresentar os elementos de concretização da metódica estruturante a partir de um caso prático, o Agravo Regimental na Reclamação n.º 3034-2 (STF). El objetivo de este estudio es investigar como el concepto de norma jurídica, desarrollada por la teoría y la metódica estructurante, se refleja en la interpretación y aplicación del derecho. El principal objetivo es analizar cómo la metódica estructurante difiere de los conceptos y métodos propuestos por las escuelas de hermenéutica jurídica precedentes. El estudio analiza las principales escuelas de hermenéutica del siglo XIX y XX, con el objetivo de perquirir la racionalidad metodológica en cada una. Presenta la caracterización de la teoría de la norma jurídica de Friedrich Müller. Analiza la relación entre norma y realidad en la teoría de la norma. Expone los conceptos de normatividad, interpretación y aplicación. Analiza la estructura de la norma y sus partes: el programa de la norma (Normprogramm) y el ámbito de la norma (Normbereich). En virtud de la conexión entre la teoría de la norma y la metódica estructurante, investiga el contexto de formación desta. Presenta los elementos de concretización de la metódica estructurante, su función y jerarquía. Por fin, intenta presentar los elementos de concretización de la metódica estructurante en un estudio de caso, el Agravo Regimental na Reclamação n.º 3034-2 (STF)
K. Kölle: Der Sprechunterricht bei geistig zurückgebliebenen Kindern. Zürich, Albert Müller. 1896. 44 S.
No full textK. KÖLLE: DER SPRECHUNTERRICHT BEI GEISTIG ZURÜCKGEBLIEBENEN KINDERN. ZÜRICH, ALBERT MÜLLER. 1896. 44 S.
Zeitschrift für Psychologie und Physiologie der Sinnesorgane (-)
Zeitschrift für Psychologie und Physiologie der Sinnesorgane (13) (a0004)
K. Kölle: Der Sprechunterricht bei geistig zurückgebliebenen Kindern. Zürich, Albert Müller. 1896. 44 S. (13) (p0240
Unidirectional photoreceptor-to-Müller glia coupling and unique K+ channel expression in Caiman retina.
No full textBACKGROUND: Müller cells, the principal glial cells of the vertebrate retina, are fundamental for the maintenance and function of neuronal cells. In most vertebrates, including humans, Müller cells abundantly express Kir4.1 inwardly rectifying potassium channels responsible for hyperpolarized membrane potential and for various vital functions such as potassium buffering and glutamate clearance; inter-species differences in Kir4.1 expression were, however, observed. Localization and function of potassium channels in Müller cells from the retina of crocodiles remain, hitherto, unknown. METHODS: We studied retinae of the Spectacled caiman (Caiman crocodilus fuscus), endowed with both diurnal and nocturnal vision, by (i) immunohistochemistry, (ii) whole-cell voltage-clamp, and (iii) fluorescent dye tracing to investigate K+ channel distribution and glia-to-neuron communications. RESULTS: Immunohistochemistry revealed that caiman Müller cells, similarly to other vertebrates, express vimentin, GFAP, S100β, and glutamine synthetase. In contrast, Kir4.1 channel protein was not found in Müller cells but was localized in photoreceptor cells. Instead, 2P-domain TASK-1 channels were expressed in Müller cells. Electrophysiological properties of enzymatically dissociated Müller cells without photoreceptors and isolated Müller cells with adhering photoreceptors were significantly different. This suggests ion coupling between Müller cells and photoreceptors in the caiman retina. Sulforhodamine-B injected into cones permeated to adhering Müller cells thus revealing a uni-directional dye coupling. CONCLUSION: Our data indicate that caiman Müller glial cells are unique among vertebrates studied so far by predominantly expressing TASK-1 rather than Kir4.1 K+ channels and by bi-directional ion and uni-directional dye coupling to photoreceptor cells. This coupling may play an important role in specific glia-neuron signaling pathways and in a new type of K+ buffering
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