Biomedical subjects
Publications and source records attributed to R Colon.
The phospholipid fatty acid composition of Amphimedoncompressa was reinvestigated and the 2-methoxyhexadecanoic acid was identified for the first time in nature. Structure characterization was accomplished by means of gas chromatography-mass spectrometry and total synthesis from commercially available 2-hydroxyhexadecanoic acid.
A 37-year-old man with atypical chest pain and complete left bundle branch block showed a marked exercise induced septal defect on Tc-99m sestamibi stress testing. A repeat examination at rest the next day revealed complete reversal of the previous septal defect. Coronary angiography two days later showed a normal coronary artery system. Left bundle branch block has been associated with false-positive results of exercise (and more recently, dipyridamole) TI-201 examinations for septal ischemia. The case presented here may be the first reported example of a false positive Tc-99m sestamibi examination for septal ischemia in the presence of left bundle block.
In marked contrast to benign cardiac tumors, primary cardiac sarcomas occur infrequently. Moreover, there is no uniform approach to treating such patients, and the benefits of postoperative chemotherapy are unclear. Between 1964 and 1989, 21 patients with primary cardiac sarcomas underwent surgical resection alone (n = 7), chemotherapy alone (n = 1), or combined operation and postoperative chemotherapy based on adriamycin (n = 13). Twenty-four operations were performed on 20 patients with relief of symptoms in all. Eleven patients had complete resection. Operative mortality was 8.3% (2/24). Histology and originating chamber(s) included angiosarcoma (n = 7; 6/7 in right atrium, 1 in left atrium), malignant fibrous histocytoma (7; all in left atrium), fibrosarcoma (2; 2/2 in left atrium), rhabdomyosarcoma (2; 1 in left atrium, 1 in right ventricle), leiomyosarcoma (2; 1 in left atrium, 1 in left ventricle); and one undifferentiated sarcoma (right atrium). Overall actuarial survival was 14% at 24 months after resection. Patients with complete resection had a median survival of 24 months compared with only 10 months in all other patients (p = 0.035). Postoperative chemotherapy did not enhance survival in patients with incomplete resection. At this time, aggressive and complete surgical resection seems to offer the best hope for palliation and survival in an otherwise fatal disease.
Between 1982 and 1987, 139 patients with primary carcinoma of the lung were treated with pneumonectomy. Thirty-nine patients (28%) were in clinical stage I, 10 (7%) were in clinical stage II, and 90 (65%) were in clinical stage III. Overall actuarial 3-year survival was 33%. Actuarial 3-year survival for patients in clinical stage I was 44%; for those in clinical stage II, 48%; and for those in clinical stage III, 28%. Risk factors for operative mortality examined included preoperative forced vital capacity (FVC) of 2.13 L or less and forced expiratory volume in 1 second (FEV1) of 1.65 L or less, percent predicted FVC of 64% or less and FEV1 of 65% or less, predicted postoperative FVC of 1.31 L or less and FEV1 of 0.89 L or less, and predicted postoperative percent predicted FVC of 41% or less and FEV1 of 34% or less. Operative deaths occurred only in clinical stage III patients (7/90 or 8%). Patients with compromised pulmonary function based on one or more of the examined risk factors were at increased risk for death (2/10) compared with patients with better pulmonary function (5/80 or 6.25%). Actuarial 3-year survival for high-risk clinical stage III patients ranged from 0% to 16% compared with 28% for other clinical stage III patients. Thirty-day mortality for pathological stage III patients was 6.3% (5/79), and 3-year actuarial survival was 24%. No patient in pathological stage III who was at high risk survived beyond 3.1 years. Select individuals with adequate pulmonary function and stage III disease can achieve substantial long-term survival after pneumonectomy.(ABSTRACT TRUNCATED AT 250 WORDS)
With the advent of cyclosporine A, heart transplantation has become a widely accepted treatment for patients with end-stage cardiac disease that is not amenable to medical or surgical treatment. Between July 1982 and December 1985, 86 heart transplantations were performed at the Texas Heart Institute with cyclosporine A and prednisone used for immunosuppression. Thirty patients had complications requiring general surgical consultation. The pancreas and biliary tracts were most commonly affected. Pancreatitis developed in sixteen patients; five patients required operative intervention, resulting in a 40% mortality rate. Five of nine patients with cholecystitis required cholecystectomy. All patients survived the procedures. Other gastrointestinal complications included colonic ileus, bowel perforation, gastrointestinal bleeding, gastric outlet obstruction, and perirectal abscess. Patients who have undergone cardiac transplantation are susceptible to life-threatening infections and are at risk of serious complications requiring general surgical intervention. Better results can be obtained in these complex clinical situations when complications are identified early and managed aggressively through the adjustment of immunosuppression, adequate selection of antimicrobial agents, and proper timing of surgical intervention.
Ischemic spinal cord injury with resulting postoperative paraplegia is an inherent risk for operations on the thoracic aorta. The mechanism of injury is not clearly understood, and numerous adjuncts to avoid this complication have been suggested, with conflicting clinical results. A new technique of hypothermic regional perfusion of the spinal cord is described. Fifteen female pigs weighing 21 to 39 kg were used for the experiment. The control group consisted of 5 animals in which the thoracic aorta was clamped at the distal arch for 30 minutes. All of these animals sustained postoperative neurological damage. Eighty percent sustained postoperative paraplegia, and 20% had severe spasticity of the hind legs that precluded normal ambulation. The experimental group consisted of 10 animals in which hypothermic regional perfusion was performed for 30 minutes after cross-clamping of the distal arch. Perfusion cooling was followed by 30 minutes of ischemia in 5 animals and 45 minutes of ischemia in the remaining 5. All animals that underwent hypothermic regional perfusion were able to walk postoperatively, and no evidence of ischemic injury was found at postmortem examination of the spinal cords. This technique proved to be simple and effective in protecting the spinal cord for up to 45 minutes of ischemia in the experimental group. The clinical implications of this concept are promising for patients undergoing operations on the thoracic aorta.
Explore the source record for details and available documents.
Blunt injuries to the heart are common and potentially lethal. These injuries often go undetected while more obvious problems are treated. A cardiac injury should be suspected in any patient who sustains severe chest trauma. The spectrum of cardiac trauma ranges from injuries with no actual cellular damage (myocardial concussion) to cardiac chamber rupture. The pathophysiology, diagnosis, and treatment of these injuries are discussed.
Early clinical experience with total artificial hearts has stimulated further research and interest in this field. The concept of total heart replacement with a permanent mechanical device has been reevaluated, and its application as a bridge to heart transplantation is becoming more widely accepted. The size of total artificial hearts, however, limits the number of cases in which they can be used. In an effort to solve this problem, we evaluated a single-ventricle artificial pump in six Hereford calves. During surgery, the left ventricle was excised and replaced with a pneumatically actuated polyurethane pump connected to the mitral and aortic valve anulus. The right ventricle provided flow through the pulmonary vasculature, which eliminated the necessity of maintaining elevated right-sided filling pressures. The single-ventricle pump required less space than a biventricular device and was capable of maintaining adequate hemodynamic parameters in experimental animals. In comparison with the biventricular pump, this device offered the advantages of less extensive dissection requirements, ease of anastomosis, and a better anatomic fit. Patients whose pericardial cavities are too small for a biventricular artificial heart may benefit from the single-ventricle pump if they require hemodynamic support while awaiting heart transplantation.