Biomedical subjects
Publications and source records attributed to J W Mackenzie.
Three cardiac surgical patients with acute postoperative renal failure were treated with a constant infusion of furosemide (Lasix) after furosemide given in bolus proved ineffective. Furosemide given continuously brought about a prompt resolution of the oliguria and tended to hasten the resolution of acute renal failure.
General surgical chief residents in all approved training programs were surveyed to evaluate the influence of fellowships, specialization, and research. Respondents represented 76% of programs and 60% of residents. Most chief residents plan to take post-residency fellowships. This is most common among those from university training programs and residents planning an academic career. Vascular surgery and cardiothoracic surgery represent half of all fellowships. Sixty-two percent of residents plan to enter private practice compared with 28% who plan to join a medical school faculty. More than one third of university trainees plan an academic career. More than 90% plan fellowships. The practice of general surgery alone or combined with a specialty was more common among trainees from independent training programs. Practice of a subspecialty was more common among university trainees. More than 80% of residents did research during training. Research leading to publication was more common among university trainees planning academic careers and least common among future general surgeons. This survey suggests that general surgery is predominant among residents in independent training programs who then enter private practice. University programs produce subspecialists who are predominant among future academic surgeons. This trend has vital implications for the future of academic general surgery.
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Rats with transplants of Morris Hepatoma 5123 excreted in their urine greater than normal amounts of modified nucleosides and bases, catabolites of RNA. Despite rapid growth of the neoplasm, the elevated levels did not appear until 22 days after inoculation with the tumor. With tumor progression, there were increased levels and number of these catabolites. This study also suggests that the source of the elevated RNA catabolites is mainly from the host RNA rather than from tumor tissue and also that mRNA and rRNA as well as tRNA may contribute to the urinary levels.
Although it has been maintained that a repeat mediastinoscopy results in high morbidity and mortality, it was considered an essential staging procedure in this group of 12 patients. The results of repeat mediastinoscopy were negative in 10 patients and positive in 2. On the basis of negative findings, 6 patients underwent thoracotomy. Five of them had a possible curative resection, and the remaining patient had an unresectable invasive carcinoma. An unnecessary thoracotomy was avoided in 2 patients with positive mediastinal nodes. For various reasons, thoracotomy was not indicated in the other 4 patients. In the evaluation of a patient with a new or recurrent pulmonary lesion, repeat mediastinoscopy can be performed safely. When findings are negative, it would appear to increase the likelihood of a curative resection, whereas when findings are positive, an unnecessary thoracotomy can be avoided.
Rats with aflatoxin-B1-induced hepatomas and dimethylnitrosamine-induced nephroblastomas excreted greater than normal amounts of urinary modified nucleosides and bases, catabolites of ribonucleic acid (RNA). Although both neoplasms caused increased excretions of the same catabolites, their quantitative profiles differed, suggesting that it may be possible to distinguish between tumors. Rats with transplanted tumors (e.g., hepatomas and osteogenic sarcomas) did not excrete elevated levels of urinary RNA catabolites until approximately 20 days after transplantation despite rapid growth of the tumor for the first 15 days. These data suggest that the source of the elevated levels of these excretory products may be the host's tissue RNA. Preliminary studies in human beings with lung cancer showed marked elevation of one or more urinary RNA catabolites. Resection of the diseased tissue in 2 patients caused a drop in levels. The measurement of urinary RNA catabolites may be useful in the diagnosis, prognosis, and evaluation of therapy in patients with lung cancer.
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Forty-six patients with diffuse, mixed malignant pleural mesothelioma were treated between January, 1970, and May, 1979. All had a history of exposure to asbestos. The diagnosis was established by thoracentesis in 3 patients, thoracoscopy in 28, thoracotomy in 5, and minithoracotomy in 9. Mediastinoscopy was performed in 31 patients and bronchoscopy in 32. Mediastinoscopy was positive in only 1 patient, and in no patient was bronchoscopy positive. Ten patients received no definitive therapy and survived an average of 9.1 months (1 lived for 16 months). Thirty-one patients received chemotherapy and survived an average of 9.6 months, the 2 longest survivors each lived for 24 months. Five patients appeared to have early disease and therefore underwent thoracotomy. In only 2 of these patients did resection of all gross disease appear possible. One patient with incomplete removal is still alive after 9 months. The other 4 are all dead, having survived an average of only 6.75 months. We believe that pleural mesothelioma should be considered an unresectable neoplasm because of its multicentric origin and its diffusely invasive nature, and that attempts at partial or complete resection are not indicated. Until prospective, controlled studies demonstrate otherwise, patients with diffuse, mixed malignant mesothelioma should have the most benign surgical procedure necessary to establish a diagnosis.
Superior vena cava syndrome can be a rapidly progressive, lethal process that is caused by a malignancy in 92 to 94% of cases. Since all effective therapy is inherently harmful, it would be reassuring to have a definitive tissue diagnosis before initiating treatment. Because easily accessible tissue is not always available, mediastinoscopy must be relied on to confirm the diagnosis in some patients. Twenty-nine patients with advanced superior vena cava syndrome were reviewed. Fifteen of them required mediastinoscopy to confirm the diagnosis, since lesser procedures, i.e., bronchoscopy, needle biopsy, and sputum cytology, were negative for malignant tissue. Contrary to reports in the literature, mediastinoscopy can be performed safely in patients with advanced superior vena cava syndrome and can yield a definitive diagnosis in each.
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Direct diagnostic thoracoscopy under general anesthesia using the mediastinoscope or bronchoscope has been done in 40 patients. No deaths or serious morbidity occurred. We recommend the use of this technique when other efforts fail to establish a diagnosis in patients with pleural disease.
The cause of granulomatous parenchymal reaction in allergic bronchopulmonary aspergillosis has been attributed to a hypersensitivity reaction. A case is reported with Aspergillus fumigatus identified in lung tissue, suggesting that the pathologic changes in some cases can be due to limited parenchymal colonization.
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