The Experts below are selected from a list of 93957 Experts worldwide ranked by ideXlab platform
Martin Bech - One of the best experts on this subject based on the ideXlab platform.
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three dimensional architecture of human diabetic peripheral nerves revealed by x ray phase contrast holographic nanotomography
Scientific Reports, 2020Co-Authors: Lars B Dahlin, Kristian R Rix, Vedrana Andersen Dahl, Anders Bjorholm Dahl, Janus Nortoft Jensen, Peter Cloetens, Alexandra Pacureanu, Simin Mohseni, Niels O B Thomsen, Martin BechAbstract:A deeper knowledge of the architecture of the peripheral nerve with three-dimensional (3D) imaging of the nerve tissue at the sub-cellular scale may contribute to unravel the pathophysiology of neuropathy. Here we demonstrate the feasibility of X-ray phase contrast holographic nanotomography to enable 3D imaging of nerves at high resolution, while covering a relatively large tissue volume. We show various subcomponents of human peripheral nerves in biopsies from patients with type 1 and 2 diabetes and in a Healthy Subject. Together with well-organized, parallel myelinated nerve fibres we show regenerative clusters with twisted nerve fibres, a sprouted axon from a node of Ranvier and other specific details. A novel 3D construction (with movie created) of a node of Ranvier with end segment of a degenerated axon and sprout of a regenerated one is captured. Many of these architectural elements are not described in the literature. Thus, X-ray phase contrast holographic nanotomography enables identifying specific morphological structures in 3D in peripheral nerve biopsies from a Healthy Subject and from patients with type 1 and 2 diabetes.
Giovanni Milano - One of the best experts on this subject based on the ideXlab platform.
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color doppler imaging and glaucoma comparison of doppler waveform and velocities of retrobulbar vessels between a glaucomatous patient and a Healthy Subject
Acta Ophthalmologica, 2014Co-Authors: Verticchio A Vercellin, Carlo Alberto Cutolo, Carolina Dellafiore, Massimiliano Lava, Carmine Tinelli, Fabrizio Calliada, Giovanni MilanoAbstract:Purpose To compare the colour Doppler imaging (CDI) waveform and velocities of the ophthalmic artery (OA), central retinal artery (CRA) and short posterior ciliary arteries (SPCA) of a patient with normal tension glaucoma (NTG) compared to a Healthy Subject. Methods The right eye of two Subjects (a patient with NTG and a Healthy Subject) were investigated. The same examiner performed CDI examination of the OA, CRA and SPCA using the CDI device ESAOTE MYLAB™ (probe LA533 13-6 MHz small parts-vascular linear array). The peak systolic velocity (PSV), the end-diastolic velocity (EDV), the resulting resistivity index (RI) were evaluated. Two aspects of the Doppler waveform were considered: the Early Systolic Acceleration (the slope of the fastest moving portion of the systolic component, ESA) and the ratio between the mean velocities of the systolic and diastolic components (Sm/Dm). Results All the measured velocities, except for the PSV in the ophthalmic artery, are reduced and the RIs are increased in the glaucomatous patient compared to the healty Subject. Moreover, ESA is reduced and Sm/Dm increased if compared to the Healthy volunteer. Conclusion The values obtained are in agreement with the literature. Further studies are needed to evaluate the degree of the pathological alterations and their role in the progression of the optic nerve injury.
Lars B Dahlin - One of the best experts on this subject based on the ideXlab platform.
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three dimensional architecture of human diabetic peripheral nerves revealed by x ray phase contrast holographic nanotomography
Scientific Reports, 2020Co-Authors: Lars B Dahlin, Kristian R Rix, Vedrana Andersen Dahl, Anders Bjorholm Dahl, Janus Nortoft Jensen, Peter Cloetens, Alexandra Pacureanu, Simin Mohseni, Niels O B Thomsen, Martin BechAbstract:A deeper knowledge of the architecture of the peripheral nerve with three-dimensional (3D) imaging of the nerve tissue at the sub-cellular scale may contribute to unravel the pathophysiology of neuropathy. Here we demonstrate the feasibility of X-ray phase contrast holographic nanotomography to enable 3D imaging of nerves at high resolution, while covering a relatively large tissue volume. We show various subcomponents of human peripheral nerves in biopsies from patients with type 1 and 2 diabetes and in a Healthy Subject. Together with well-organized, parallel myelinated nerve fibres we show regenerative clusters with twisted nerve fibres, a sprouted axon from a node of Ranvier and other specific details. A novel 3D construction (with movie created) of a node of Ranvier with end segment of a degenerated axon and sprout of a regenerated one is captured. Many of these architectural elements are not described in the literature. Thus, X-ray phase contrast holographic nanotomography enables identifying specific morphological structures in 3D in peripheral nerve biopsies from a Healthy Subject and from patients with type 1 and 2 diabetes.
Cecilia Guariglia - One of the best experts on this subject based on the ideXlab platform.
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Developmental topographical disorientation in a Healthy Subject.
Neuropsychologia, 2010Co-Authors: Filippo Bianchini, Laura Piccardi, Liana Palermo, Chiara Incoccia, Laura Zompanti, Umberto Sabatini, Patrice Péran, Cecilia GuarigliaAbstract:We present the case of F.G., a Healthy, normally developed 22-year-old male Subject affected by a pervasive disorder in environmental orientation and navigation who presents no history of neurological or psychiatric disease. A neuro-radiological examination showed no evidence of anatomical or structural alterations to the brain. We submitted the Subject for a comprehensive neuropsychological assessment of the different cognitive processes involved in topographical orientation to evaluate his ability to navigate the spatial environment. The results confirmed a severe developmental topographical disorder and deficits in a number of specific cognitive processes directly or indirectly involved in navigation. The results are discussed with reference to the sole previously described case of developmental topographical disorientation (Pt1; Iaria et al., 2009). F.G. differs from the former case due to the following: the greater severity of his disorder, his complete lack of navigational skills, the failure to develop compensatory strategies, and the presence of a specific deficit in processing the spatial relationships between the parts of a whole. The present case not only confirms the existence of developmental topographical-skill disorders, but also sheds light on the architecture of topographical processes and their development in human beings.
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Developmental topographical disorientation in a Healthy Subject
'Elsevier BV', 2010Co-Authors: Filippo Bianchini, Laura Piccardi, Liana Palermo, Chiara Incoccia, Laura Zompanti, Umberto Sabatini, Patrice Péran, P. Pecan, Cecilia GuarigliaAbstract:We present the case of F.G., a Healthy, normally developed 22-year-old male Subject affected by a pervasive disorder in environmental orientation and navigation who presents no history of neurological or psychiatric disease. A neuro-radiological examination showed no evidence of anatomical or structural alterations to the brain. We submitted the Subject for a comprehensive neuropsychological assessment of the different cognitive processes involved in topographical orientation to evaluate his ability to navigate the spatial environment. The results confirmed a severe developmental topographical disorder and deficits in a number of specific cognitive processes directly or indirectly involved in navigation. The results are discussed with reference to the sole previously described case of developmental topographical disorientation (Pt1; Iaria et al., 2009). F.G. differs from the former case due to the following: the greater severity of his disorder, his complete lack of navigational skills, the failure to develop compensatory strategies, and the presence of a specific deficit in processing the spatial relationships between the parts of a whole. The present case not only confirms the existence of developmental topographical-skill disorders, but also sheds light on the architecture of topographical processes and their development in human beings. (C) 2010 Elsevier Ltd. All rights reserved
Rudolf Giovanoli - One of the best experts on this subject based on the ideXlab platform.
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citrate determines calcium oxalate crystallization kinetics and crystal morphology studies in the presence of tamm horsfall protein of a Healthy Subject and a severely recurrent calcium stone former
Nephrology Dialysis Transplantation, 2000Co-Authors: B Hess, Samuel Jordi, L Zipperle, Emma Ettinger, Rudolf GiovanoliAbstract:BACKGROUND The aim of this study was to measure the effects of normal (nTHP) and abnormal stone former Tamm-Horsfall protein (SF-THP) on calcium oxalate (CaOx) nucleation and aggregation as well as on crystal morphology, in presence or absence of citrate. METHODS Nucleation and aggregation of CaOx crystals from a supersaturated, stirred solution (200 mM NaCl, 10 mM Na-acetate, pH 5.70, 5 mM Ca and 0.5 mM Ox) were studied by spectrophotometric time-course measurements of OD at 620 nm (OD(620)). Measured parameters were induction time t(I) (time to induce formation of detectable particles), S(N), (slope of increase of OD(620), mainly due to crystal nucleation), and S(A), (slope of decrease of OD(620) after equilibrium has been reached, due to crystal aggregation). Effects of citrate, nTHP and SF-THP on these parameters were measured, and scanning electron microscopy (SEM) was performed. RESULTS At 1.5, 2.5 and 3.5 mM, citrate increased t(I) and inhibited crystal nucleation (by 78-87%) as well as aggregation (by 63-70%), and smaller CaOx crystals (length/width ratio 1.7+/-0.1) than under standard conditions (length/width 3.9+/-0.5) were visible (P<0.001). Normal THP at 30 and 40 mg/l inhibited crystal nucleation and, more strongly, aggregation (inhibition 76-81%). SEM revealed a decrease in length/width ratio to 2.6+/-0.4 (P=0.051 vs standard conditions) and less aggregation than without nTHP. At all concentrations tested, SF-THP reduced t(I) (P=0.0001 vs standard conditions) and promoted aggregation (inhibition -48 to -33%); crystals were elongated with a length/width ratio of 4.3+/-0.6 (P<0. 05 vs nTHP). When simultaneously present with nTHP, citrate enhanced the inhibitory effects of nTHP, producing the smallest (length/width 1.5+/-0.1) and least aggregated crystals. Finally, 3.5 mM citrate turned promotory SF-THP into a crystallization inhibitor with abundant small and clustered, but not aggregated crystals. CONCLUSION Citrate appears to be the main determinant of CaOx crystallization rates and crystal morphology in the presence of nTHP as well as SF-THP. Its effects appear to predominate over those of THP, since even promotory SF-THP is turned into a crystallization inhibitor in the presence of citrate. This re-emphasizes at a morphological level what has been concluded from functional as well from clinical studies, namely that citrate is needed in urine at equimolar concentrations to calcium in order to prevent the formation of large crystal aggregates in presence of abnormal THP.
