Quantitative Assessment of Anteroposterior Keratocyte Density in the Normal Rabbit Cornea
Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas 75235-9057. Cornea
(Impact Factor: 2.04).
02/1995; 14(1):3-9. DOI: 10.1097/00003226-199501000-00002
The anteroposterior keratocyte density distribution in the rabbit cornea was measured. Unsectioned tissue blocks from the central cornea of five rabbits were stained with propidium iodide and imaged using a Leica laser scanning confocal microscope. A z-series of images was acquired confocal microscope. A z-series of images was acquired in each sample, from anterior to posterior stroma in either 3- or 8-microns steps. Software was developed to allow interactive marking of the keratocyte nuclei within each section of the z-series and for calculating cell density. For convenience, cell density was expressed as the number of cells per corneal volume element (CVE), where CVE is a newly defined volume unit with x, y, and z dimensions of 250, 250, and 10 microns, respectively. The calculated keratocyte density was 20.2 +/- 1.0 cells/CVE (n = 5), which is equivalent to 32,360 +/- 1,660 cells/mm3. The greatest density was underneath the epithelium (26.3 +/- 2.5 cells/CVE), the density then decreased linearly with depth to 15.2 +/- 1.4 cells/CVE; there was a slight increase in density pre-Descemets membrane to 18.5 +/- 3.5 cells/CVE. A 30% decrease in cell density over the entire anteroposterior stromal thickness was observed. To facilitate statistical analysis, the cell density was averaged over 5% thickness intervals from anterior to posterior cornea. A significant difference in mean cell density of these intervals was found (ANOVA, n = 20, p < 0.01). To further assess the density distribution, linear regression analysis was performed. A significant correlation was found between keratocyte density and stromal depth (R = -0.94, n = 20, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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ABSTRACT: Les lapins sont des animaux que l'on rencontre de plus en plus fréquemment au cours des consultations car les enfants apprécient leur pelage doux et les parents les apprécient pour le peu d'entretien qu'ils demandent ( nettoyage de la cage deux fois par semaine). Les problèmes d'ophtalmologie constituent le second motif de consultation après les problèmes dentaires chez le lapin domestique ( Oryctolagus cuniculi). Ils sont souvent à l'origine d'une forte mortalité, soit parce que les traitements efficaces sont inexistants, soit le plus souvent parce qu'ils sont présentés trop tardivement en consultation. L'auteur présente ici les différences anatomiques du lapin par rapport aux animaux plus couramment présenté au cabinet ainsi que les différents traitements possibles qui peuvent être utilisés en pratique ou qui sont testés en laboratoire.
Available from: Nir Giladi
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ABSTRACT: Freezing episodes and related phenomena (as a general term, motor blocks [MBs]) are poorly understood, particularly disabling, and a therapeutically frustrating problem in Parkinson's disease (PD). Epidemiologic and clinical characteristics of MBs, as well as risk factors to develop MBs, have never been fully addressed. Herein, we report our database survey on 990 PD patients, of whom 318 (32%) had MBs. The majority of MBs were linked to gait. Start hesitation occurred in 86%, blocking on turning in 45%, and blocking in narrow spaces in 25% of patients. Initial parkinsonian symptoms in the upper body and tremor as the initial motor symptom were less likely to be associated with the presence of MBs (odds ratios [OR] 0.6 and 0.7, respectively), while initial symptoms affecting gait or trunk had higher association with MBs (OR = 1.58). Longer disease duration, higher Hoehn and Yahr stage, and longer duration of levodopa treatment are all significantly associated with the presence of MBs. We observed significant association between the existence of MBs and levodopa-induced dyskinesias to suggest similar pathophysiology. We propose that MBs in PD are abnormal retrieval or execution of complex motor tasks that can occur as a result of disease progression or as short- or long-term side effects of levodopa treatment.
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