1,721,091 research outputs found

    Saffron and retina: Neuroprotection and pharmacokinetics

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    Age-related macular degeneration (AMD) is a retinal neurodegenerative disease whose development and progression are the results of a complex interaction between genetic and environmental risk factors. Both oxidative stress and chronic infl ammation play a signifi cant role in the pathogenesis of AMD. Experimental studies in rats with light-induced photoreceptors degeneration demonstrated that saffron may protect photoreceptor from retinal stress, preserving both morphology and function and probably acting as a regulator of programmed cell death, in addition to its antioxidant and anti-infl ammatory properties. Recently, a randomized clinical trial showed that in patients with early AMD, dietary supplementation with saffron was able to improve signifi cantly the retinal fl icker sensitivity suggesting neuroprotective effect of the compound. Here, we examine the progress of saffron dietary supplementation both in animal model and AMD patients, and discuss the potential and safety for using dietary saffron to treat retinal degeneration

    Functional laser Doppler flowmetry of the optic nerve: physiological aspects and clinical applications

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    The present paper reviews the methodology and clinical results of recording, by laser Doppler flowmetry, the hemodynamic response of the optic nerve head elicited by visual stimulation. The basic mechanism underlying this novel technique (which is called here functional laser Doppler flowmetry (FLDF)) is the coupling between visually evoked neural activity and vascular activity within the neural tissue of the optic nerve (neurovascular coupling). The blood flow responses elicited by various visual stimuli (luminance and chromatic flicker, focal and pattern stimulation) have been characterized in humans by FLDF. These responses are similar to those assessed by electrophysiological methods (flicker and pattern electroretinography) evoked by the same stimuli. In addition, a significant correlation has been demonstrated between the hemodynamic responses and the neural activity induced electrical signals arising from the inner retina, providing evidence in support of the presence of a neurovascular coupling in humans. The application of FLDF in patients with ocular hypertension and early glaucoma demonstrates that the visually evoked hyperemic responses are significantly depressed even when neural retinal activity may be still relatively preserved, suggesting that abnormal optic nerve head autoregulation in response to visual stimuli may be altered early in the disease process. FLDF may open new avenues of investigation in the field of glaucoma and other neuro-ophthalmic disorders, providing new pathophysiological data and outcome measures for potential neuro-protective treatments

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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
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