Advances in Animal Cardiology
Online ISSN : 1883-5260
Print ISSN : 0910-6537
ISSN-L : 0910-6537
Volume 32, Issue 2
Displaying 1-4 of 4 articles from this issue
ORIGINALS
  • Shin-ichiro KATSUDA, Masamitu HASEGAWA, Masahiko KUSANAGI, Noboru MACH ...
    1999 Volume 32 Issue 2 Pages 25-36
    Published: 1999
    Released on J-STAGE: November 18, 2005
    JOURNAL FREE ACCESS
    We investigated effects of atherosclerosis on mechanical distensibility characteristics of the aorta in the KHC rabbit at 10-12 months of age in relation to alteration in histological fine architecture and compared with those in the normal rabbit of the same age range. Circumferential strips of the aortic wall at 3 mm in width were sampled from the ascending, proximal and middle thoracic, and proximal and distal abdominal aortas for tension-strain and stress-strain tests and from the ascending, proximal thoracic and proximal abdominal aortas for stress-relaxation test. The strips were mounted into especially-designed chucks of a chamber fixed to tensile testing instruments, immersed into the Ringer's solution at 37°C and sretched at a speed of 4.17 mm⁄sec by indicating tension at 20-40 g for tension-strain and stress-strain tests and at a speed of 83.33 mm⁄sec by 50% to the initial length for stress-relaxation test.The strips were kept stretched for 5 min to measure relaxation strength 5 min after the stretching for the latter test. The aortic wall in the KHC rabbit showed marked viscoelastic properties, e.g. a significant decrease in wall stress and elastic modulus, and a significant increase in relaxation strength in comparison to those in the normal rabbit, above all, in the ascending, proximal thoracic and proximal abdominal aortas in which atheromatous plaque with abundant cholesterol-rich foam cells was observed. In addition to the viscoelastic properties, a decrease in distensibility, e.g. a significant increase in wall tension was observed in the ascending aorta, which is partly due to proliferation of the collagen fibers. We can conclude that mechanical distensibility characteristics of the aortic wall reflect severity of alteration in the wall architecture due to atherosclerosis.
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  • Kouji NAKAHARA, Takayuki MURAKAMI
    1999 Volume 32 Issue 2 Pages 37-41
    Published: 1999
    Released on J-STAGE: November 18, 2005
    JOURNAL FREE ACCESS
    The pulmonary atresia with ventricular septal defect was observed in 11 (1.93%) of 570 bovine hearts showing congenital cardiovascular anomalies. In all cases the infundibulum of the right ventricle was hypoplastic and the pulmonary valvular level was atretic. The pulmonary trunk was a blind cord in seven cases, in remaining four cases the trunk was patent but its diameter was smaller than the left and right pulmonary arteries. All cases had left and right pulmonary arteries, and the arteries were confluent and supplied by a patent ductus arteriosus within the pericardial cavity.
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  • Yasuo MOROHOSHI, Shigenobu NAKAYAMA, Takao KANAI, Tadao IKEDA, Noriaki ...
    1999 Volume 32 Issue 2 Pages 42-48
    Published: 1999
    Released on J-STAGE: November 18, 2005
    JOURNAL FREE ACCESS
    In order to investigate ECG changes during myocardial infarction and post-ischemic reperfusion, we need animal model that allows us to establish coronary occlusion with selected vessels, set occlusion time and manipulate the degree of myocardial injury and infarct size. In our study, we made Amplatz-type cardiac catheter for rabbits to develop non-invasive procedure. A stainless bead is attached at the tip of guide wire which was placed in the right or left coronary artery to produce occlusion and procedure for reperfusion was investigated. ECGs were recorded during occlusion and reperfusion of the left coronary artery, showing typical QT prolongation and elevation of ST segment and T wave, “Bead occlusion⁄reperfusion” is an effective procedure which can be used to study rabbit model of myocardial ischemia and infarction.
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