1,721,425 research outputs found
William Harvey in quarantine and lazaretto when back to Italy at the time of 1630 plague
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Pathology of the aorta and aorta as homograft
No full textThe aorta is not a rigid tube, it is an “organ” with lamellar units, consisting of elastic fibers, extracellular matrix and smooth muscle cells in between as parenchyma. Several diseases may occur in the natural history of the aorta, requiring replacement of both semilunar cusps and ascending aorta. They may be congenital defects, such as bicuspid aortic valve and isthmal coarctation with aortopathy; genetically determined, such as Marfan and William syndromes; degenerative diseases, such as atherosclerosis and medial necrosis with aortic dilatation, valve incompetence and dissecting aneurysm; inflammatory diseases such as Takayasu arteritis, syphilis, giant cell and IgM4 aortitis; neoplasms; and trauma. Aortic homografts from cadavers, including both the sinus portion with semilunar cusps and the tubular portion, are surgically employed to replace a native sick ascending aorta. However, the antigenicity of allograft cells, in the lamellar units and interstitial cells in the cusps, is maintained. Thus, an immune reaction may occur, limiting durability. After proper decellularization and 6 months’ implantation in sheep, endogenous cell repopulation was shown to occur in both the valve and aortic wall, including the endothelium, without evidence of inflammation and structural deterioration/calcification in the mid-term. The allograft was transformed into an autograft
Diamond Anniversary of Mechanical Cardiac Valve Prostheses: A Tale of Cages, Balls and Discs
No full textThis year marks the 60th anniversary of the first aortic and mitral valve replacements using mechanical artificial prosthesis. The first caged-ball devices represented a milestone in cardiac surgery and in treatment of valvular disease. The following decades witnessed a great evolution in mechanical valve technology providing, through frustrating complications and stimulating successes, more reliable models to be safely used in the clinical setting. This review pays a tribute to pioneers of this field who made currently available the most advanced models of mechanical prostheses with extended records of durability and performance, to be used as reliable alternatives to biological devices
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