There are a number of cardiovascular diseases that are characterized by weakness of supportive connective tissue, examples of which are cystic median degeneration of the aorta, dissecting aortic aneurysm, the syndrome of 'click murmur' (floppy) of the mitral valve, Marfan's syndrome and aneurysms of the membranous septum. Currently there is no satisfactory medical means of treatment for patients with these diseases. Laboratory evidence suggests that androgenic steroids, reserpine, and propranolol affect the accumulation and intramolecular crosslinking of collagen in two experimental models: (1) the repair connective tissue of the rat; and (2) the aorta of an inbred strain of turkey that develops dissecting aneurysms spontaneously. It is proposed to use the turkey model to identify those anabolic steroids having a high collagen crosslinking-enhancement effect and a low virilizing property and to evaluate possible synergistic actions between the steroid and reserpine and/or propranolol in enhancing crosslinking of vascular scleroprotein. The drug combination found to promote the greatest scleroprotein content and the maximum crosslinking of collagen and elastin in the vascular tissue of the turkey will be tested for its therapeutic effects on patients with Marfan's syndrome. The efficacy of the treatment will be monitored by determining crosslinking of the soluble and insoluble collagens of dermal biopsies taken from patients before and during thrapy and by periodic clinical evaluation of the patients before and during treatment.