Abstract: A contrast agent for magnetic resonance imaging comprising a complex of a paramagnetic cation, preferably Gd+3, Dy+3, and Fe+3 with three equivalents of a charge neutralizing chelator that provides a lipid soluble complex of the paramagnetic cation is described. The complex is retained intracellularly when introduced into a mammalian cell. A method of providing an image of an internal pathology of a patient by magnetic resonance imaging (MRI) by administering the MRI contrast agent or tagged cells to the patient and scanning the patient using magnetic resonance imaging to obtain visible images of the internal pathology of the patient is also set forth.

Abstract: A process for the treatment of collagenous tissue to adapt it for use in a prosthetic implant and to promote the growth of endothelial cells thereon after implantation comprising treatment with at least one surfactant prior to fixation, treatment with agents which inhibit calcification and agents which resist attack by phagocytic cells and optional treatment with stabilizing agents.