Psychosocial and physiological predictors of sudden cardiac death after healing of acute myocardial infarction

Several major prospective studies that have examined the relation between type A behavior and cardiac mortality have failed to find an association. Since psychosocial factors have been implicated in the etiology of sudden cardiac death, it is possible that this association may emerge if sudden cardiac death is distinguished as an outcome distinct from other cardiac mortality. Predictors of sudden death and other cardiac outcomes were examined using data from the Recurrent Coronary Prevention Project, a 4.5-year prospective clinical trial of 1,012 postinfarction patients begun in San Francisco in 1978. A unique set of risk factors was found for the differing outcomes: sudden cardiac death had predominantly psychosocial predictors while nonsudden cardiac death and nonfatal recurrences were predominantly predicted by biologic factors. Type A behavior was an independent predictor of sudden, but not nonsudden, cardiac death in this population (p = 0.04). These results are the first demonstration of a direct relation between stress and sudden cardiac death in a large prospective clinical study, and provide insight into the failure of past prospective studies to find an association between type A behavior and cardiac mortality.     

In situ saphenous vein bypass grafts: angiographic evaluation and interventional repair of complications

In situ saphenous vein grafts are being used with increasing frequency for bypass procedures involving the femoral and popliteal arteries. Complications of these procedures include anastomotic stenoses and persistent arteriovenous fistulae that may result in failure of the graft. Balloon angioplasty and embolotherapy with detachable balloons were employed successfully in three or four recent cases of patients with complications from in situ grafts. Tailored angiography is essential for evaluating in situ grafts, and interventional techniques are extremely useful for managing complications.     

The effects of antioxidant supplementation during Percoll preparation on human sperm DNA integrity

The integrity of sperm DNA is crucial for the maintenance of genetic health. A major source of damage is reactive oxygen species (ROS) generation; therefore, antioxidants may afford protection to sperm DNA. The objectives of the study were, first, to measure the effects of antioxidant supplementation in vitro on endogenous DNA damage in spermatozoa using the single cell gel electrophoresis (comet) assay and, second, to assess the effect of antioxidant supplementation given prior to X-ray irradiation on induced DNA damage. Spermatozoa from 150 patients were prepared by Percoll centrifugation in the presence of ascorbic acid (300, 600 microM), alpha tocopherol (30, 60 microM), urate (200, 400 microM), or acetyl cysteine (5, 10 microM). DNA damage was induced by 30 Gy X-irradiation. DNA strand breakage was measured using the comet assay. Sperm DNA was protected from DNA damage by ascorbic acid (600 microM), alpha tocopherol (30 and 60 microM) and urate (400 microM). These antioxidants provided protection from subsequent DNA damage by X-ray irradiation. In contrast, acetyl cysteine or ascorbate and alpha tocopherol together induced further DNA damage. Supplementation in vitro with the antioxidants ascorbate, urate and alpha tocopherol separately has beneficial effects for sperm DNA integrity.