Alterations in the distribution of high-energy phosphates during ischemia in a canine model of reperfusion-induced ventricular fibrillation

High-energy phosphate metabolites of the canine heart were analyzed before coronary artery occlusion and after 15 minutes of ischemia, and the results were then correlated with the occurrence of ventricular fibrillation upon reperfusion (RVF). Animals which developed VF upon reperfusion after 15 minutes of ischemia had lower levels of creatine phosphate and endocardial adenosine triphosphate (ATP), and increased accumulation of the catabolites of ATP metabolism, inosine and hypoxanthine. Animals which developed RVF also had lower levels of regional myocardial blood flow in the center of the ischemic zone during the period of coronary occlusion. Occluded bed size was the same in dogs which did and did not develop RVF. These data suggest that VF upon reflow is associated with more severe ischemia and an increase in high-energy phosphate catabolism during the period of ischemia.     

Ethical dilemmas in caring for patients with the acquired immunodeficiency syndrome

Caring for patients with the acquired immunodeficiency syndrome (AIDS) raises ethical dilemmas about when to provide life-sustaining treatments such as mechanical ventilation and cardiopulmonary resuscitation. In addition, many patients become mentally incompetent and unable to participate in decisions. Homosexual men may want their lover or a friend to make decisions for them, but the patient's partner or friend cannot make these decisions unless he is legally designated. Decision-making guidelines may be hard to implement because caring for patients with AIDS is stressful. We describe three cases that illustrate the difficult ethical dilemmas and stresses of caring for these patients.     

MR angiography in abdominal neoplasms

The role of magnetic resonance angiography (MRA) in the evaluation of vascular involvement was studied in 55 patients with abdominal neoplasms. A 2-D time-of-flight (TOF) technique was used in 18 patients. All patients underwent CT and MR examinations before MRA. Also, MR angiograms were compared with digital subtraction angiography in 22 cases, with Doppler US in 13 cases, and with surgical findings in 20 cases. In all patients with liver neoplasms (n = 29) MRA demonstrated the absence of flow in the infiltrated segments. Pericapsular neovascularization was observed in 12 patients. Portal vein involvement was correctly detected in 27 patients. In all cases MRA demonstrated the relationship between the tumor and venous structures. Portosystemic shunts were visualized in 20 of 21 patients with portal hypertension. Vena cava thrombosis (3 cases), compression (5 cases), and displacement (2 cases) were correctly demonstrated. In renal (n = 6) and adrenal gland (n = 3) tumors renal vein compression was correctly detected in 2 cases, displacement in 1 case, and thrombosis in 3 cases, with only 1 false-positive finding. In 7 patients with pancreatic tumors MRA demonstrated splenic vein thrombosis in 2 cases and compression in 2 cases, with one false-positive finding. Our results indicate that MRA provides precise information regarding venous vascular involvement in abdominal neoplasms, but preoperative arterial mapping is still problematic. Correspondence to: E. Squillaci