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Spontaneously occurring restrictive nonhypertrophied cardiomyopathy in domestic cats: a new animal model of human disease.
No full textBACKGROUND:
Spontaneously occurring small animal models of myocardial disease, closely resembling the human condition, have been reported for hypertrophic cardiomyopathy (in cats) and arrhythmogenic right ventricular cardiomyopathy (in cats and boxer dogs). Nonhypertrophied restrictive cardiomyopathy (RCM) is a well-recognized but relatively uncommon primary heart muscle disease causing substantial morbidity in humans. We describe RCM occurring in felines here as a potential model of human disease.
METHODS:
We used two-dimensional and Doppler echocardiography to define morphologic and functional features of RCM in 35 domestic cats (25 male; 10±4 years old) presenting to a subspecialty veterinary clinic. Ten underwent complete necropsy examination. Echocardiographic parameters of diastolic filling were compared to those in 41 normal controls.
RESULTS:
The 35 cats presented with congestive heart failure (n=32), lethargy (n=2), or syncope (n=1), associated with thromboembolism in 5 and supraventricular tachyarrhythmias in 8. During an average 4.4-year follow-up period, 18 died or were euthanized due to profound heart failure, and 3 died suddenly; survival from clinical presentation to death was 0.1 to 52 months. Echocardiographic and necropsy examination showed biatrial enlargement, nondilated ventricular chambers, and normal wall thicknesses and atrioventricular valves. Histopathology demonstrated disorganized myocyte architecture and patchy replacement myocardial fibrosis. Pulsed Doppler demonstrated restrictive physiology with increased early (E) mitral filling velocity (1.1±0.3 m/s) and peak E to peak late (A) flow ratios (4.3±1.2), reduced A filling velocity (0.3±0.1 m/s), and shortened mitral deceleration time (40.7±9.3 ms; all P<.001 vs. controls), with preserved left ventricular systolic function.
CONCLUSIONS:
A primary myocardial disease occurring spontaneously in domestic cats is remarkably similar to restrictive nondilated and nonhypertrophied cardiomyopathy in man and represents another potential animal model for human diseas
Spontaneously occurring arrhythmogenic right ventricular cardiomyopathy in the domestic cat: a new animal model similar to the human disease
No full textSpontaneous occurrence of arrhythmogenic right ventricular cardiomyopathy in the domestic cat: a new animal model of human disease
No full textBACKGROUND:
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a primary myocardial disease of incompletely resolved pathogenesis and is a largely unappreciated cause of sudden death in the young.
METHODS AND RESULTS:
Clinical features of 12 domestic cats with ARVC (7 male; 1 to 20 years old, mean 7.3+/-5.2 years) were right-sided congestive heart failure (n=8), supraventricular tachyarrhythmias (n=5), ventricular tachycardia (n=3), polymorphic ventricular arrhythmias (n=6), and right bundle-branch block (n=5). ARVC was suspected in all 8 cats examined with echocardiography by marked enlargement of the right ventricle (RV) and right atrium and tricuspid regurgitation. Eight died of cardiovascular disease and 4 died of noncardiac conditions. At autopsy, hearts of ARVC cats were characterized grossly by moderate-to-severe RV cavity enlargement and wall thinning (n=12) and apical aneurysm formation (n=6). Histology demonstrated pronounced RV lesions in all 12 ARVC cats, including marked myocardial injury (myocyte death and atrophy) and repair (fibrous and/or fatty replacement). Injury and repair were also evident in the left ventricle (LV) in 10 cats, and 2 had involvement of both atria. Myocarditis was present in 10 of the 12 ARVC cats. Apoptosis was detected in 9 ARVC cats (mean apoptotic index, 28+/-23% RV, 21+/-19% LV, and 17+/-15% ventricular septum) but not in controls.
CONCLUSIONS:
In the common domestic cat, we identified a clinically relevant cardiomyopathy that closely mimics ARVC in humans. This unique feline model of human disease will be relevant to defining pathogenesis and investigating mechanisms responsible for disease progression in ARVC
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Arrhythmogenic right ventricular cardiomyopathy causing sudden cardiac death in boxer dogs - A new animal model of human disease
Full text linkBACKGROUND:
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a primary familial heart muscle disease associated with substantial cardiovascular morbidity and risk of sudden death. Efforts to discern relevant pathophysiological mechanisms have been impaired by lack of a suitable animal model.
METHODS AND RESULTS:
ARVC was diagnosed in 23 boxer dogs (12 male; 9.1+/-2.3 years old). Clinical events alone or in combination included sudden death (n=9; 39%), ventricular arrhythmias of suspected right ventricular (RV) origin (n=19; 83%), syncope (n=12, 52%), and heart failure (n=3; 13%). Right ventricular enlargement or aneurysms occurred in 10 (43%). Striking histopathological abnormalities were present in each boxer dog but not in controls, including severe RV myocyte loss with replacement by fatty (n=15, 65%) or fibrofatty (n=8, 35%) tissue. Focal fibrofatty lesions were also present in both atria (n=8) and the left ventricle (LV) (n=11). Fatty replacement occupied substantially greater RV wall area in ARVC dogs than controls (40.4+/-18.8% versus 13.8+/-3.4%, respectively) (P<0.001); residual myocardium was correspondingly reduced (56.6+/-19.2% versus 84.8+/-3.8% in controls) (P<0.001). MRI demonstrated bright anterolateral and/or infundibular RV myocardial signals, confirmed as fat by histopathology. Myocarditis appeared in the RV (n=14, 61%) and LV (n=16, 70%) and in each dog with sudden death, but not in controls. Familial transmission was evident in 10 of the 23.
CONCLUSIONS:
We describe a novel, spontaneous, and genetically transmitted animal model of ARVC associated with sudden death in the boxer dog, closely resembling the human disease. This model may aid in understanding the pathogenic mechanisms of ARVC
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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