Biomedical subjects
Publications and source records attributed to N A Halasz.
This study included 71 cadavers used for anatomical dissection that had undergone cholecystectomies. Of these five, 7% had some type of hepatic artery injury. The subjects all had survived at least 1 year after cholecystectomy and had normal livers. The mechanisms of this injury, its pathophysiology, and its prevention are discussed.
Organ transplantation has made tremendous strides in the last decade. The demand for transplantable organs has far outstripped the supply; waiting lists have grown long and patients are dying for want of vital organs. Therefore policies and criteria that guide the allocation of transplantable organs become ever more important. Over the years, allocation policies have evolved by including both medical and ethical considerations, and much work has gone into defining and analyzing components of such policies. However, they have often grown by accretion, and a parallel analysis of both sets of approaches did not occur. This article attempts to integrate medical and ethical considerations, and to develop a schema that will permit review, redefinition, and--it is hoped--development of a fairer, more equitable and responsive allocation system.
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Primary bacterial peritonitis and catheter-associated infections compose the large majority of abdominal events in continuous ambulatory peritoneal dialysis (CAPD) patients. Yet occasionally primary pathology involving the abdominal viscera develops, and surgery is frequently considered. The early manifestations of intraabdominal inflammation or bleeding in patients undergoing CAPD depend on the pathological process, its access to the peritoneal cavity, and whether generalized bacterial peritonitis supervenes to obscure helpful physical findings. Clear dialysate is not a reliable sign that major pathology is absent, nor does initial stabilization of the clinical course with antibiotic therapy uniformly indicate that surgery will not be necessary. Polymicrobial peritonitis may develop in cholecystitis, pancreatitis, or from a colonic source, the latter featuring more bacterial species and more gram-negative and anaerobic organisms. A history directed at progression of symptoms and sites of abdominal discomfort and an examination for deep local tenderness and bowel incarcerated in an abdominal wall hernia are essential. Measurement of dialysate amylase and Gram stain of dialysate for food fibers may be helpful. Imaging techniques such as abdominal radiographs for dilated bowel or free subdiaphragmatic air, ultrasonography of the gallbladder or pancreas, computed tomographic (CT) scanning of the lower abdomen, and water-soluble contrast colonic studies may help identify the pathologic process. Special studies such as these should be considered early in the course of suspected unusual abdominal events in patients on CAPD.
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Recent advances in the understanding of desmoid tumor biology affect therapeutic choices. This series of 19 patients and review of the literature outlines historic perspectives and discusses the options in the management of these locally aggressive tumors. Desmoid tumors tend to grow steadily, regardless of tumor location. However differences in the aggressive nature of these tumors are seen when age and sex distributions are scrutinized. Although recurrence rates are high, excisional therapy is the best first approach. An exception is the case in which tumor excision is either particularly dangerous or likely to result in significant physical handicap. Radiation or drug therapy are most often used with recurrent disease or as an alternative to mutilating surgery. Although many pharmacologic approaches have been advocated, (including antiestrogen therapy, cyclic-AMP, and prostaglandin inhibition), results are anecdotal at best.
Previous studies showed the beneficial effects of superoxide dismutase +/- catalase in perfusion-preserved rabbit kidneys but failed to show benefit in flush-cooled organs. The current studies undertook to evaluate scavengers, xanthine oxidase inhibitors, and agents that prevent the release of myeloperoxidase in 3 systems: kidneys preserved by perfusion or by flush cooling for 24 hr, studied immediately, and warm ischemia-injured kidneys evaluated after a 24-hr recovery period. In none of these groups could we demonstrate any protective effects against preservational or warm ischemic injury by the above modalities. Even though biochemical and other evidence from previous studies suggested free radical-induced injury to occur in preserved rabbit kidneys, these studies using renal function as the indicator did not do so.
Vascular resistance changes were measured in response to alteration in perfusate osmolarity in isolated rabbit kidneys perfused at 10 degrees C. The data obtained were found to fit a simple mathematical model of the vascular resistance of the microcirculation in which it was assumed that variation in this parameter depended solely upon osmotic alterations in the size of the cells within and around the blood vessel walls. The model predicts that the volumetric changes due to the different osmolarities are produced in a tissue layer whose thickness is 30% relative to a fixed outer radius. This result is compatible with the hypothesis that the effects are predominantly due to changes of endothelial cell volume and other perivascular capillary cells. The analysis illustrates the significance of perfusate osmolarity as a determinant of vascular resistance, can be used to investigate the hemodynamic effects that occur during the introduction and removal of cryoprotective agents, and is relevant to the interpretation of results obtained with hypertonic solutions in blood volume restoration after hypovolemic shock.
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Seventy-seven patients underwent transplantation, using a cyclosporine-prednisone immunosuppression protocol. No recipients died, and graft survival at one year was 100% for living related donor (LRD) recipients and 84% for cadaver donor (CD) recipients. Nineteen percent of locally harvested, flush-cooled kidney recipients required dialysis, whereas imported kidneys had a 66% dialysis rate. Infectious complications occurred in 17% of patients. Mean hospitalization was 12.8 days for LRD recipients and 13.6 days for CD recipients. Twenty-eight patients required 37 readmissions, mostly for treatment of rejection and infections. Total two-year cost for LRD transplants was +21,400; for CD transplants, +23,900.
This study evaluated the effect of specific scavengers of oxygen derived free radicals on the results of kidney preservation. The immediate function of rabbit kidneys preserved for 24 hr by hypothermic perfusion was studied on an ex vivo shunt. A significant improvement in creatinine clearance was seen when the perfusate was treated with superoxide dismutase (SOD) and catalase (CAT), with values of 261 +/- 82 ml/hr vs control values of 203 +/- 72 ml/hr, P less than 0.05. This effect was enhanced if a long-persistent polyethylene glycol-linked form of SOD, namely PEG-SOD, was used (330 +/- 58 ml/hr, P less than 0.01). Recipient treatment and other modifications designed to protect against free radicals resulted in similar improvement in function. In contrast, no effect of free radical scavengers could be demonstrated in kidneys which were preserved by flush cooling, whether the agents were added to the flushing solution, given to the recipient, or both.
Percutaneous catheter drainage was performed in 16 patients with diverticulitis complicated by abscesses. Each patient had resolution of fever within 72 hours. Eleven patients subsequently underwent simultaneous sigmoid resection and operative anastomosis 10-40 days after percutaneous drainage. One patient required a three-stage procedure after percutaneous drainage, and one patient was too unstable for operation at any time during her course and eventually died of respiratory failure. Three patients did not undergo resection after catheter drainage and have remained asymptomatic for 1-2 1/2 years. Ten of 16 patients had fistulas, eight of which closed spontaneously. Experience with percutaneous drainage of diverticular abscesses suggests that it obviates surgical abscess drainage and permits a single operation (sigmoid resection and closure) to be performed safely. Percutaneous abscess drainage has cost-saving implications, since one or two operations may be avoided in most patients, and in some high-risk elderly patients all operations may be obviated.
Twenty-five patients who had lymphoceles underwent sectional imaging and interventional radiologic procedures. Viewed using sonography, lymphoceles were hypoechoic to anechoic, occasionally with internal septa and debris. Low numbers (occasionally negative values) were observed using computed tomography (CT); these numbers strongly suggest the diagnosis of lymphocele. Calcification was observed on CT images of one patient. Diagnostic aspiration revealed tan to yellow fluid containing many lymphocytes; pathognomonic fat globules were observed in four cases. Malignant cells were found in two collections, an unusual occurrence. Therapeutic needle aspiration and short-term catheter drainage were usually unsuccessful (only one of five patients [20%] was cured). Long-term (1-5-week) catheter drainage cured 11 of 14 patients (78.6%). Sclerosing agents may have been beneficial for lymphocele obliteration in three of four patients. For most patients, lymphoceles may be diagnosed and treated successfully using radiologic means.
Diagnostic and therapeutic radiologic experience with six patients who had oriental cholangiohepatitis is described. These patients combined had 10 prior operations. Postoperatively each had recurrent cholangitis, numerous stones, concretions, and/or bile duct strictures. Diagnostically, sonography was valuable in the detection of intra- and extrahepatic stones and extrahepatic dilatation of ducts. An important pitfall in sonography was poor visualization of intrahepatic ductal dilatation (due to echogenic sludge filling the ducts) in most patients. CT was helpful diagnostically in all respects. Interventional procedures used postoperatively included percutaneous transhepatic intrahepatic stones, and flushing techniques. Most patients were treated during multiple sessions as outpatients. Cholangitis was the only complication from the procedures. Sectional imaging and interventional radiology perform valuable diagnostic and therapeutic roles in the pre- and postoperative management of patients with oriental cholangiohepatitis.
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This study was conducted to determine whether an optimum redox electrode potential existed for 24-hr hypothermic perfusion of rabbit kidneys. The perfusate consisted of a Ringer's-albumin solution to which was added varying amounts of the reducing agents, glutathione and ascorbate, either individually or in equimolar amounts. Electrode potential was monitored with a vitreous carbon electrode in relation to a silver-silver chloride reference cell, and kidney function was measured after preservation by connection to the circulation of a perfusor animal via a shunt. The best results were obtained using equimolar amounts of the reducing agents. Under these circumstances a definite optimum range for perfusate electrode potential was identified (Es = 40-70 mV) within which renal function was indistinguishable from unpreserved controls. Higher and lower perfusate electrode potentials were associated with significantly lower creatinine clearances. However, the explanation for these results appeared to be more complex than redox control alone, since kidney function was dependent not only on the redox potential of the perfusate but also on the reducing agents with which the adjustment had been made. Ascorbate proved to be significantly better than glutathione within the optimum potential range.
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