The effect of manufacturing variables on radiation doses from porcelain tiles.

Previous studies have focused on the radiological properties of glazed ceramic tiles. This study was conducted to describe the radiological properties of porcelain tiles and how they were affected by variations in the manufacturing parameters. The data showed that the majority of the uranium in the tiles was attributable to the addition of zircon while less than half of the thorium in the tile was attributable to the added zircon, and the remainder came from other minerals in the formulation. The effects of firing temperatures and compressive strengths of the tiles are presented and show that higher firing temperatures increase radon emanation, while higher compressive strengths reduce radon emanation. The study also described how the addition of zircon to the tile formulation affected the radiological exposures that could be received by a member of the public from the use of such porcelain tiles. A dose assessment was conducted based on 23 different types of tile formulation. Screening procedures for building materials have been described in European Commission documents, and these limit the addition of zircon in a porcelain tile to approximately 9% by mass. The dose assessment reported in this study showed that 20% zircon could be added to a porcelain tile without exceeding the prescribed dose limits.

Medical services for our financially needy elderly patients.

Physicians as a profession are concerned about the health care needs of financially needy elderly patients. A program of voluntary assignment is suggested as the best solution for this problem. Mandated assignment would lead to diminished access to medical care and diminished quality. A voluntary assignment program, in cooperation with senior citizens organizations, offers a cooperative effort to cover the elderly in need of medical care.

Preliminary experience with intraoperative transluminal balloon-catheter dilation and coronary artery bypass grafting for the treatment of symptomatic diffuse coronary artery disease.

Transluminal balloon-catheter dilation of coronary artery lesions has become increasingly common in the cardiac catheterization laboratory. We describe a method of intraoperative dilation that may improve surgical results when used in combination with coronary artery bypass graft (CABG) operations in patients with diffusely diseased coronary arteries. In 16 patients, long-segment intraoperative dilations were performed to enlarge luminal narrowings in 21 different regions. All of these patients had postoperative coronary angiography and left ventriculography so that we could objectively evaluate the coronary dilatations. There were no operative deaths or perioperative myocardial infarctions, and angina was relieved in all patients. Of the 21 dilated segments, 12 (57%) were unchanged, 2 (10%) became worse, and 7 (33%) were improved postoperatively. In addition, two new areas of intimal damage were detected in patients with unchanged postoperative liminal diameters. We conclude that further experience and longer follow-up are necessary before the efficacy of intraoperative coronary artery balloon-catheter dilation can be accurately determined.

Axillofemoral bypass grafts using polytetrafluoroethylene.

More liberal indications for axillofemoral bypass grafts have recently been advocated if long-term patency were comparable to aortic bypass procedures. A clinical trial of polytetrafluoroethylene (PTFE) axillofemoral grafts was instituted in an attempt to maximize graft patency. The theoretic advantages of this material were: (1) a more rigid tube graft, (2) a surface impermeable to blood, (3) a thin pseudointima, and (4) better tissue incorporation. During the last two years, 29 axillofemoral bypass grafts of PTFE have been inserted. Four have failed, one of them now functioning after successful thrombectomization. The cumulative patency rate (life table) for 21 months is 79% "patent" grafts and 84% "functioning" grafts. Six patients have died (21%). There have been three complications, all involving avulsion of the graft at the proximal or distal anastomosis. There have been no infections. Our early results support broadened indications for axillofemoral grafts, since patency rates are comparable to those for aortoiliac/femoral grafts in many series. The characteristics of PTFE appear to be largely responsible for the early success of these grafts, with minimized blood loss and graft hematomas. Great care is required in sizing this rigid tube because tension may produce graft avulsion.

Local anesthesia for mediastinoscopy: experience with 450 consecutive cases.

Mediastinoscopy has been widely applied in the evaluation of patients with suspected bronchogenic carcinoma over the past decade. Though there remain those who feel that such findings should not play a significant role in determining resectability, we have found a number of patients who have been saved from exploratory thoracotomy in obviously incurable situations. We have had a relatively high degree of success in the diagnosis of benign diseases. Wtih no mortality and a morbidity of 1.1%, we feel that mediastinoscopy under local anesthesia is applicable in many clinical circumstances in which the requirement for general anesthesia would preclude such evaluation. Though it is not necessary that local anesthesia be exclusively applied, we feel that our experience with over 450 cases in the last six years has demonstrated safety and efficacy in universal application of local anesthesia for cervical mediastinal exploration.

Unusual aspects of atrial myxoma.

Cardiac myxomas are infrequently encountered lesions. Certain aspects of these tumors are unusual and include right atrial location, calcification, valve destruction, hematologic abnormalities, occurrence in children, and familial occurrence. A 12-year-old girl manifesting all of these unusual aspects of myxoma is described and each of the unusual aspects is discussed.

Mitral valve replacement with a porcine heterograft in an infant.

Mitral valve replacement for congenital mitral stenosis has been performed infrequently in infants. In all but two previously reported infants, the valve has been replaced with a mechanical prosthesis. The case history of an infant is reported in whom emergency mitral valve replacement was successfully performed with a porcine heterograft excised from a tubular prosthesis. This approach is an acceptable alternative when a valve of appropriate size is unavailable.

Coronary revascularization in patients maintained on chronic hemodialysis.

Thirty-two thousand patients are presently maintained in chronic dialysis programs. Cardiovascular complications have been shown to be responsible for 50 to 65% of the deaths in such patients. Despite this and the increasingly frequent use of coronary bypsss surgery in the general population, only two patients have previously been reported to have successfully undergone coronary bypass surgery while maintained on chronic hemodialysis. This reports two additional such patients who successfully underwent coronary revascularization without difficulty. Pertinent details of preoperative, intraoperative, and postoperative management are outlined for these patients and the other 13 chronic dialysis patients who have had cardiopulmonary bypass for other reasons. With careful planning, coronary revascularization can be successfully carried out in this group of patients with minimally increased operative risk.

Arteriovenous malformation in chronic gastrointestinal bleeding.

Arteriovenous malformations of the gastrointestinal tract are uncommon and treatment is problematic because routine barium contrast studies and endoscopy fail to demonstrate the lesion. Diagnosis is by selective mesenteric arteriography, demonstrating a characteristic vascular tuft and very early venous phase. Two cases of arteriovenous malformation are presented and 47 other reported cases are reviewed. Forty-five per cent were found in the cecum; 37, or 80%, involved the distal ileum, cecum ascending colon, or hepatic flexure. Seventy-five per cent of all patients fall into the 50--80 year age range. The literature reveals a recurring pattern of chronic gastrointestinal blood loss, anemia, and delay (even negative abdominal explorations) before the diagnosis is finally made. A more aggressive approach to chronic gastrointestinal bleeding is suggested through the use of selective mesenteric arteriography.