1,25-Dihydroxyvitamin D3 inhibits the proliferation of the chronic myelogenous leukemia cell line RWLeu-4 but not the resistant variant, JMRD3. Although these cells exhibit no detectable differences in the vitamin D receptor, alterations in the interaction of nuclear extracts with the osteocalcin-1,25-dihydroxyvitamin D3-response element are noted. It is shown herein that the 1,25-dihydroxyvitamin D3 receptor binds to the osteocalcin-1,25-dihydroxyvitamin D3-response element along with activator protein-1 (AP-1) complexes and that the DNA binding activities of members of the Jun and Fos proto-oncogene families, which make up the AP-1 transcription factor, are differentially regulated by 1,25-dihydroxyvitamin D3. It is shown that JunD DNA binding activity is enhanced by 1,25-dihydroxyvitamin D3 during cell cycle arrest in the sensitive cells but is decreased in the resistant cells. These results suggest that the level of JunD DNA binding activity may be a critical factor in the regulation of proliferation.

Dacron prostheses are the most widely used grafts in replacement procedures for abdominal aortic aneurysms, having been proven as the most reliable substitute for arterial replacement. However, we present herein the rare case of an 82-year-old woman in whom nonanastomotic aneurysm formation occurred in the graft as a complication associated with a Dacron prosthesis. The patient presented with a pulsatile mass in the right inguinal region. She had undergone surgery 13 years earlier for an abdominal aortic aneurysm, at which time an aortobifemoral graft reconstruction had been performed with a double-velour knitted Dacron prosthesis. The pulsatile mass was found to be a nonanastomotic aneurysm of the right limb of the bifurcated graft with an intact distal anastomosis. In this case, the development of the graft aneurysm seemed to result from deterioration of the Dacron prosthesis itself due to mechanical fatigue caused by the inguinal band.

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