1,720,985 research outputs found
Ganglioside treatment of neuropathy in diabetic mice
No full textDiabetic neuropathy in 180-day-old C57BL/Ks inbred mice is characterized by a marked reduction of nerve conduction velocity (NCV) and by axonal atrophy, as suggested by the decreased number of large diameter myelinated fibers. No demyelination or remyelination was observed. Ganglioside treatment from 150 to 180 days of age significantly improved the NCV and returned the fiber size distribution to control values
Functional and morphological abnormalities induced by ouabain intoxication of the rabbit retina
No full textSeveral researchers have recently used an intravitreal ouabain injection to induce a suitable model of experimental retinopathy and optic neuropathy in various animals. Ouabain administration into the vitreous body of rabbit causes an irreversible degeneration of the retinal layers and consequently of the optic nerve. The degeneration is proportional to the amount of injected drug. Electroretinographic recordings (ERG) show that these structural abnormalities are related to an inhibition of the electric retinal activity as the dose-dependent reduction of ERG waves amplitude has shown. Moreover, ERG and visual evoked responses (VER) measured at the same time evidence that the intravitreal injection of 1.7 nmol ouabain may block the impulse conduction along the optic nerve. This can be proved by the fact that 90 min after an ouabain injection VER disappears, while ERG is only partially reduced. These results are correlated with both morphological observation and autoradiographic studies on3H-ouabain distribution in different retinal layers
Monosialoganglioside (GM1) treatment of ouabain-induced retinopathy in the rabbit
No full textThe mammalian retina is markedly influenced by cardiac glycosides. When nanomolar concentrations of ouabain are intravitreously injected into the rabbit, the visually evoked response completely disappears within 90 min, while scotopic ERG recordings show a remarkably decreased amplitude of the principal waves. When 33 nmol/kg monosialoganglioside are injected intravenously 30 min before topical intoxication, this functional impairment is significantly reduced. The electroretinographic response shows a limited amplitude reduction, while the cortical potential nerver disappears completely. Histological observations of intoxicated retinas show that a degenerative process begins in photoreceptor outer segment 24 h after the intravitreal ouabain injection. Presently, this process involves both the outer and inner nuclear layers and, finally, the ganglion cell layer. Comparing the intoxicated treated and untreated retinas, no difference is found in the degenerative pattern of the two groups. Autoradiographic studies are also reported to correlate the protective effect of monoganglioside (GM1) on this toxic retinopathy with its preferential accumulation in different retinal tissues
Development of diabetic neuropathy in the C57BL/Ks (db/db) mouse and its treatment with gangliosides
No full textWe studied the development of diabetic neuropathy and its treatment with gangliosides using the C57BL/Ks mouse. The results of axonal morphometry showed the presence of a progressive axonal atrophy which was maximal at 180 days of age. To 400 days of age there was no longer any significant difference, perhaps due to aging processes. Nerve conduction velocity changed significantly from the early days of life. Thirty-day treatment with gangliosides significantly improved nerve conduction velocity and axonal morphometry at 180 and 280 days of life. No effect was observed with treatments at 30 or 60 days. It was previously shown that the early phase of the C57BL/Ks mouse neuropathy was reversed by insulin, whereas the late phase (180 days) was not. We showed elsewhere that at 180 days of age in the C57BL/Ks mouse there was a drastic decrease in slow transport of AChE (G1 and G2 molecular forms) indicating a shift in neuronal metabolism and suggesting that the disease was then more intrinsically neuronal. Using the suggestion of Robertson and Sima (Diabetes 29: 60-67, 1980) we label the first phase of the neuropathy 'metabolic' (treatable with insulin) and the second phase 'neuronal' (treatable with gangliosides). This 'neuronal' phase could be related to the degenerative stage of human diabetic neuropathy
Asylum-Città rifugio. Progetto di sistemazione per le Caserme e aree militari a Milano. Workshop Scuola di Architettura Civile
No full textVoltage- and Activity-Dependent Chloride Conductance Controls the Resting Status of the Intact Rat Sympathetic Neuron
No full textIsolation and possible role of fast and slow potassium current components in hair cells dissociated from frog crista ampullaris.
No full textPotassium-current inactivation and recovery kinetics are pivotal in sustaining dynamic processing of time-varying sensory signals in hair cells. We report a detailed analysis of K(+)-currents in isolated hair cells from the frog crista ampullaris. The single components were dissected using a novel procedure based on their differential kinetic properties: The fast IA component exhibited two processes of inactivation removal; the persistent I (KD) component (I (KV) + I (KCa)), unexpectedly displayed partial inactivation, removed by negative potentials with particularly slow, delayed kinetics. The physiological relevance of these observations was investigated by imposing sinusoidal membrane potential changes to mimic receptor response to hair bundle deflection. The excitatory phase elicited extra-currents (hysteresis) only if the off phase went sufficiently negative to remove IA inactivation. Native, resting hair cells are depolarised by receptor current; thus, voltage continuously modulates I(KD), whereas IA only transiently ensues when the receptor current vanishes (zero-current potential approximately -70 mV) and polarisation removes IA inactivation
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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