ABSTRACT
Alzheimer's disease (AD) is a prevalent, long-term progressive degenerative disorder with great social impact. It is currently thought that, in addition to neurodegeneration, vascular changes also play a role in the pathophysiology of the disease. Visual symptoms are frequent and are an early clinical manifestation; a number of psychophysiologic changes occur in visual function, including visual field defects, abnormal contrast sensitivity, abnormalities in color vision, depth perception deficits, and motion detection abnormalities. These visual changes were initially believed to be solely due to neurodegeneration in the posterior visual pathway. However, evidence from pathology studies in both animal models of AD and humans has demonstrated that neurodegeneration also takes place in the anterior visual pathway, with involvement of the retinal ganglion cells' (RGCs) dendrites, somata, and axons in the optic nerve. These studies additionally showed that patients with AD have changes in retinal and choroidal microvasculature. Pathology findings have been corroborated in in-vivo assessment of the retina and optic nerve head (ONH), as well as the retinal and choroidal vasculature. Optical coherence tomography (OCT) in particular has shown great utility in the assessment of these changes, and it may become a useful tool for early detection and monitoring disease progression in AD. The authors make a review of the current understanding of retinal and choroidal pathological changes in patients with AD, with particular focus on in-vivo evidence of retinal and choroidal neurodegenerative and microvascular changes using OCT technology.
Subject(s)
Alzheimer Disease/complications , Choroid Diseases/diagnosis , Retinal Diseases/diagnosis , Tomography, Optical Coherence/methods , Choroid/pathology , Choroid Diseases/etiology , Humans , Optic Disk/pathology , Retinal Diseases/etiology , Retinal Ganglion Cells/pathologyABSTRACT
DC reactive magnetron sputtered Ag:TiO2 nanocomposite thin films were developed to be used as protective coatings in pressure sensor devices. The coatings, with Ag content varying from 0 to about 30 at.%, were prepared and characterized in order to study their biological response. The as-deposited samples were annealed in vacuum at 500 °C in order to evaluate the influence of their morphological and structural differences over the response elicited upon contact with simulated bodily fluids and cultured human cells, as well as selected microorganisms. The results showed that the annealing treatment produced less porous films with an enhanced structure, with a significant reduction in structural defects and improved crystallinity. Additionally, samples with higher Ag contents (≥12.8 at.%) exhibited Ag agglomerates/clusters at the surface, a result anticipated from the XRD data. The crystallization of the TiO2 matrix was also observed by XRD analysis, albeit delayed by the dispersion of Ag into the matrix. Biological characterization showed that the antimicrobial activity and cytotoxicity of the coatings were directly related with their composition, closely followed by the particular structural and morphological features, namely those resulting from annealing process.
Subject(s)
Coated Materials, Biocompatible , Silver/chemistry , Titanium/chemistry , Microscopy, Atomic Force , Microscopy, Electron, Scanning , PressureABSTRACT
Panic disorder patients, obsessive-compulsive disorder (OCD) patients, and normal control subjects performed a computerized Stroop color-naming task in which they named the colors of panic-threat words (e.g. Collapse), general-threat words (e.g. Infectious), positive words related to panic (e.g. Relaxed), and neutral words (e.g. Sleepy). Idiographic stimulus selection ensured their personal emotional relevance for each subject. In accordance with prediction, panic patients, but not OCD patients, exhibited greater interference for panic-threat words than for positive words related to panic and for neutral words. Panic patients did not respond differentially to panic-threat and general-threat words. Complexities concerning attentional bias research in the anxiety disorders are discussed.
Subject(s)
Cognition , Emotions , Language , Panic Disorder/diagnosis , Female , Humans , Male , Obsessive-Compulsive Disorder/diagnosis , Obsessive-Compulsive Disorder/psychology , Panic Disorder/psychology , Psychiatric Status Rating Scales , VocabularyABSTRACT
Panic-disordered (PD) patients, obsessive-compulsive (OCD) patients, and normal control subjects were exposed to either a high (i.e. exercise) or low arousal manipulation prior to performing a computerized version of the modified Stroop color-naming paradigm. Subjects named the colors of neutral nonlexical stimuli, positive words, and threat words associated with fear, bodily sensations, and catastrophes. After the Stroop task, subjects rated the personal emotional significance of the words. Inconsistent with the emotionality hypothesis of Stroop interference, PD patients rated positive words as more emotional than catastrophe words, but took longer to color-name the latter than the former. Yet consistent with the emotionality hypothesis, PD patients took as long to color-name positive words as to color-name fear and bodily sensation words. Contrary to expectation, OCD patients resembled PD patients in terms of interference, and arousal did not enhance interference for threat words in PD patients.
