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Zhou Y.,University of Pittsburgh | Cattley R.T.,University of Pittsburgh | Cario C.L.,Tsinghua University | Bai Q.,Geriatric Research | Burton E.A.,Pittsburgh Veterans Affairs Healthcare System
Nature Protocols | Year: 2014

This article describes a method to quantify the movements of larval zebrafish in multiwell plates, using the open-source MATLAB applications LSRtrack and LSRanalyze. The protocol comprises four stages: generation of high-quality, flatly illuminated video recordings with exposure settings that facilitate object recognition; analysis of the resulting recordings using tools provided in LSRtrack to optimize tracking accuracy and motion detection; analysis of tracking data using LSRanalyze or custom MATLAB scripts; and implementation of validation controls. The method is reliable, automated and flexible, requires <1 h of hands-on work for completion once optimized and shows excellent signal:noise characteristics. The resulting data can be analyzed to determine the following: positional preference; displacement, velocity and acceleration; and duration and frequency of movement events and rest periods. This approach is widely applicable to the analysis of spontaneous or stimulus-evoked zebrafish larval neurobehavioral phenotypes resulting from a broad array of genetic and environmental manipulations, in a multiwell plate format suitable for high-throughput applications. © 2014 Nature America, Inc. All rights reserved. Source

Liu J.,University of Pittsburgh | Rattan R.,University of Pittsburgh | Adelstein E.,University of Pittsburgh | Barrington W.,University of Pittsburgh | And 11 more authors.
Circulation: Arrhythmia and Electrophysiology | Year: 2012

Background-The Food and Drug Administration recently issued a class I recall of the St. Jude Medical Riata implantable cardioverter-defibrillator lead presumably because of increased risk of electric failure and mechanical separation via inside-out abrasion. We sought to examine the incidence and time dependence of inside-out abrasion in asymptomatic patients implanted with the Riata lead. Methods and Results-Asymptomatic patients implanted with the Riata lead at our institution were offered voluntary fluoroscopic screening in 3 views. Electric testing of the Riata lead with provocative isometric muscle contraction was performed at the time of fluoroscopic screening. Of the 245 patients undergoing fluoroscopic screening, 53 (21.6%) patients showed clear evidence of lead separation. Of these externalized leads, 0%, 13%, and 26% had a dwell time of <3 years, 3 to 5 years, and >5 years, respectively (P=0.037). Externalized leads had a significantly pronounced decrease in R-wave amplitude (?1.7±2.9 mV versus +0.35±2.5 mV; P<0.001), and more patients with externalized leads had ?25% decrease in R-wave amplitude from baseline (28.0% versus 8.1%; P=0.018). One patient with externalization exhibited new noise on near-field electrogram. Conclusions-The Riata lead exhibits time-dependent high rates of cable externalization exceeding 20% at >5 years of dwell time. Externalized leads are associated with a more pronounced decrease in R-wave amplitude, which may be an early marker of future electric failure. The use of fluoroscopic and electric screening of asymptomatic patients with the Riata lead remains controversial in the management of patients affected by the recent Food and Drug Administration recall. © 2012 American Heart Association, Inc. Source

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