 amyloid starch gel electrophoret analysi protein extract amyloid protein extract strong urea wash tissu patient amyloidosi secondari diseas associ famili mediterranean fever common major electrophoret compon heart primari amyloidosi compon common secondari amyloid primari amyloid difficult dissolv regularli compon observ secondari amyloid extract big question remain constitu constitu compris fibril amyloid 