276 research outputs found

    Electrocardiography in Wistar rat experimental model: analysis and characterization

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    El modelo experimental de rata Wistar es ampliamente utilizado por la comunidad científica para la evaluación de xenobióticos y estresantes ambientales. Sin embargo, a pesar de su gran uso, pocas publicaciones ´ han reportado explícitamente las diferencias entre los parámetros obtenidos del delineamiento del ECG para las distintas variables que intervienen en la configuración de un experimento con rata Wistar. Variables como la anestesia suministrada, el sexo, la edad, el peso, la restricción del movimiento y la derivación utilizada influyen significativamente ´ en los parametros electrocardiográficos analizados, tales como, los intervalos RR, QT y PR, las duraciones P y QRS, y las amplitudes pico de las ondas P, Q, R, S y T. El primer objetivo específico de este trabajo es organizar los parámetros electrocardiográficos que ya han sido publicados por la comunidad científica según su setup experimental. El segundo objetivo específico es aportar nuevos parámetros, como los intervalos JTend y Tpe, al estado del arte de ´ la caracterizacion del ECG de rata Wistar. Para ello, una base de datos de 48 ratas Wistar categorizadas por sexo y edad, medida en la derivación II, fue procesada y delineada.The experimental model of Wistar rat(WR) is widely used by the scientific community for the evaluation of xenobiotics and environmental stressors. However, in spite of its great use,few publications have explicitly reported the differences between the parameters obtained from the ECG delineation and the different variables involved in the settings of a Wistar rat experiment. Variables such as supplied anesthesia, sex, age, weight, movement restriction and lead used influence the electrocardiographic parameters analyzed, such as RR, QT, PR intervals, P and QRS durations and peak amplitudes of P, Q, R, S, and T-waves. The first specific objective of this work is to organize the electrocardiographic parameters that have already been published by the scientific community according to their experimental setup. The second specific objective is to provide new parameters, such as the JTend and Tpe intervals, to the state of the art of Wistar rat ECG characterization. For this purpose, a database of 48 Wistar ratscategorized by sex and age, measured in lead II, was processed and delineated.Fil: Caracciolo, Santiago Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Bertran, Guillermo Claudio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Arini, Pedro David. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto Argentino de Matemática Alberto Calderón; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; Argentin

    Preclinical evaluation of carbon-11 and fluorine-18 sulfonamide derivatives for in vivo radiolabeling of erythrocytes

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    Cardiac dysfunction in the diabetic rat: quantitative evaluation using high resolution magnetic resonance imaging

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    BACKGROUND: Diabetes is a major risk factor for cardiovascular disease. In particular, type 1 diabetes compromises the cardiac function of individuals at a relatively early age due to the protracted course of abnormal glucose homeostasis. The functional abnormalities of diabetic myocardium have been attributed to the pathological changes of diabetic cardiomyopathy. METHODS: In this study, we used high field magnetic resonance imaging (MRI) to evaluate the left ventricular functional characteristics of streptozotocin treated diabetic Sprague-Dawley rats (8 weeks disease duration) in comparison with age/sex matched controls. RESULTS: Our analyses of EKG gated cardiac MRI scans of the left ventricle showed a 28% decrease in the end-diastolic volume and 10% increase in the end-systolic volume of diabetic hearts compared to controls. Mean stroke volume and ejection fraction in diabetic rats were decreased (48% and 28%, respectively) compared to controls. Further, dV/dt changes were suggestive of phase sensitive differences in left ventricular kinetics across the cardiac cycle between diabetic and control rats. CONCLUSION: Thus, the MRI analyses of diabetic left ventricle suggest impairment of diastolic and systolic hemodynamics in this rat model of diabetic cardiomyopathy. Our studies also show that in vivo MRI could be used in the evaluation of cardiac dysfunction in this rat model of type 1 diabetes

    T wave detection and analysis

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    Detekce a analýza amplitudy T vlny Kardiovaskulární onemocnění jsou jednou z nejčastějších příčin úmrtí na celém světě, a proto je nezbytně nutné mít k dispozici nástroj, který umožní rychlé, bezpečné a levné rozpoznání nemoci. Takovým nástrojem je elektrokardiografie (EKG). Algoritmy automatizované analýzy parametrů EKG jsou běžnou složkou moderních elektrokardiografů, nicméně analýza signálů při výskytu patologie srdce je problematická kvůli změnám v jednotlivých parametrech EKG křivky. Cílem této bakalářské práce je návrh algoritmu pro automatizovanou detekci a analýzu amplitudy T vlny a jeho aplikace na datech registrovaných v experimentálním modelu akutní ischemie a reperfuze. Následná analýza amplitudových charakteristik T vlny je zaměřena na vyhodnocení možnosti předpovídání vzniku maligních arytmií na základě amplitudy T vln. Algoritmus byl realizován ve vývojovém prostředí MATLAB. Analyzovaný soubor obsahoval 187 EKG záznamů z 21 laboratorních potkanů za různých fyziologických a patologických stavů. Naměřené hodnoty byly porovnány po skupinách pomocí různých statistických testů. Pro zpracování a kontrolu výsledků byly využity statistický software IBM SPSS a tabulkový procesor Microsoft Excel 365. Vysoká míra spolehlivosti počítačového měření byla prokázána pomocí Bland-Altmanovy analýzy a koeficientů vnitrotřídní korelace. Při porovnání rychlostí měření bylo zjištěno, že počítačové zpracování šetří minimálně 5,33 minuty na každém signálu. Analýza amplitudových charakteristik objevila v porovnání s původním stavem nárůst amplitudy T vln během 1. minuty reperfuze v I. svodu a během ischemie ve III. svodu. Další analýza ukázala, že amplituda T vln u citlivých na arytmie zvířat za původního stavu je nižší v I. svodu a vyšší ve III. svodu v porovnání se zvířaty bez komorových arytmií.T-wave Detection and Analysis Cardiovascular diseases are one of the most frequent causes of death all over the world and therefore it is essential to have a tool that enables a fast, safe and cheap recognition of the disease. Such a tool is electrocardiography (ECG). Automatized analyses of ECG parameters algorithms are a common part of modern electrocardiographs, nevertheless a signal analysis, when heart pathology occurs, is problematic due to the changes in individual ECG curve parameters. The aim of this bachelor thesis is a proposal of an algorithm for an automatized detection and analysis of T wave amplitude and its use on the data registered in an experimental module of acute ischemia and reperfusion. The following analysis of a T wave amplitude characteristics is aimed at an evaluation of malign arrythmia based on T waves amplitude prediction possibility. The algorithm was implemented in a development environment MATLAB. The analyzed group contained 187 ECG records from 21 laboratory rats in various physiological and pathological conditions. The obtained data were compared in groups through various statistic tests. For data and check processing, statistic software IBM SPSS and Microsoft Excel 365 spreadsheet were used. A high rate of computer measurement reliability was proved through a Bland-Altman analysis and interclass correlation coefficients. A comparison of the measurement speed revealed that the computer processing saved minimally 5,33 minutes in every signal. An amplitude characteristics analysis discovered an amplitude T waves increase during the first minute of reperfusion in Ist lead and during ischemia in IIIrd lead. The following analysis revealed that T waves amplitude in animals sensitive to arrhythmia in original condition was lower in Ist lead and higher in IIIrd lead in comparison with animals without ventricular arrhythmia

    Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 212

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    A bibliography listing 146 reports, articles, and other documents introduced into the NASA scientific and technical information system is presented. The subject coverage concentrates on the biological, psychological, and environmental factors involved in atmospheric and interplanetary flight. Related topics such as sanitary problems, pharmacology, toxicology, safety and survival, life support systems, and exobiology are also given attention
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