Biomedical subjects
Publications and source records attributed to B Powell.
Foam tape used to protect epidural catheters during immersion in a Dornier HM3 lithotriptor was identified retrospectively as the cause of poor stone fragmentation. Studies of shock wave penetration through various protective type materials indicate that a particular water repellant tape is least likely to impair shock wave penetration.
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The technique of tissue expansion using inflatable expanders has gained widespread attention in the surgical literature. We give two examples of its use and emphasise possible complications which may arise. The search for methods to close complex wounds, often associated with radiation-damaged tissue or exposed bone, has resulted in a progression from random skin flaps to axial pattern flaps with a longer length to breadth ratio guaranteed by anatomically constant vessels. Musculocutaneous, fasciocutaneous and free flaps have been described over the body surface allowing complex reconstruction at local and distant sites. The use of expansion is of particular value in allowing local tissue to fill defects with minimal functional and aesthetic disturbance. In the face and scalp, in particular, tissue expansion appears to be a promising method of at least partially removing disfiguring lesions and is useful in reconstruction following traumatic loss. The concept of tissue expansion in medicine is not new. During pregnancy the abdominal skin becomes gradually stretched over the expanding uterus. Large skin excisions can be carried out in abdominoplasty following weight loss. Skin and mucosa can be seen to expand rapidly over benign enlarging neoplasms. The serial excision of large naevi has been practised for many years by plastic surgeons. Skin grafts placed over fasciotomy wounds to obtain tension-free closure can be subsequently excised in stages to obtain a minimally stretched linear scar.
One hundred ninety-five adult patients with refractory or first relapse acute myelogenous leukemia (AML) were randomly assigned to receive high-dose cytarabine (HiDAC), 3 g/m2 as a three-hour intravenous (IV) infusion every 12 hours for four doses, followed by 6,000 IU/m2 asparaginase (ASNase) administered at hour 42, or HiDAC without ASNase. Treatment was repeated on day 8. The median patient age was 52 years. There was an overall superior complete remission (CR) rate for HiDAC/ASNase (40%) v HiDAC (24%), P = .02. Subset analysis according to prior response and age showed the following CR rates: 54% from HiDAC/ASNase treatment of refractory AML in patients less than 60 years, and 31% in patients greater than 60 years; CR from HiDAC in the same refractory groups were 18% (less than 60) and 0% (greater than 60); 37% from HiDAC/ASNase treatment of relapsed AML in patients less than 60 years, and 43% in patients greater than 60 years; CRs from HiDAC in the same relapsed groups were 33% (less than 60) and 21% (greater than 60). Toxicity in the two treatment arms was comparable and consisted primarily of leukopenia, thrombocytopenia, mild hepatic dysfunction, diarrhea, conjunctivitis and serositis, and hyperglycemia. There was only one case of transient cerebellar toxicity and no cutaneous toxicity. Median time to full hematologic recovery was 5 weeks. There was an overall survival benefit for patients treated with HiDAC/ASNase (19.6 weeks) compared with HiDAC (15.9 weeks), P = .046, primarily attributable to effects in refractory patients. Median time to failure for refractory patients who achieved CR was 38.5 weeks with HiDAC/ASNase, and 13.3 weeks for those treated with HiDAC. For relapsed patients in CR from HiDAC/ASNase the median time to failure was 17.7 weeks and 18.3 weeks for HiDAC. The overall 42% CR rate from HiDAC/ASNase v 12% from HiDAC in patients with refractory AML indicates that HiDAC/ASNase is not cross-resistant with standard-dose cytarabine (SDAC) and anthracyclines. We conclude that HiDAC/ASNase has substantial activity in poor-prognosis AML and that this combination warrants further trials in earlier stage disease.
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A 4-cm leiomyoma was found in a woman with the Rokitansky-Kuster-Hauser syndrome. It was discovered six years after she presented to a gynecologist. In the ensuing years she successfully developed vaginal dilation. This is the fourth reported case of leiomyoma associated with the Rokitansky-Kuster-Hauser syndrome.
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Second primary carcinomas of the lung are well described. However, their occurrence following initial diagnosis of small cell lung carcinoma is rare. The development and antemortem diagnosis of metachronous second primary bronchogenic carcinomas in two long-term (more than four years) survivors of small cell lung cancer is described. The histologic types of the second carcinomas were mucoepidermoid and bronchoalveolar. On the basis of a review of the literature, only eight similar cases have been reported; none of the second primaries was mucoepidermoid or bronchoalveolar. The question of whether second primaries after small cell lung cancer represent true metachronous carcinomas, different degrees of differentiation of the same tumor, or the emergence of a previously unrecognized synchronous tumor is discussed. The need for awareness of this complication and the necessity for life-long follow-up in long-term survivors of small cell lung cancer is emphasized.
Physical exertion can cause migraine or the benign exertional headache. The case is presented of a 30-year-old male weight lifter who experienced excruciating headache while doing leg presses on a weight machine. Physical examination was normal, as were subsequent examinations. The patient resumed training with lighter weights and did not again experience headaches. Some experts estimate that up to 4% of the adult population engages in weight lifting occasionally, and thus this malady may be more common than is realized.
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An identifiable histamine-containing neuron is located on the anterior dorsal surface of the visceral ganglion of Lymnaea stagnalis L. After [3H]histamine was injected into the perikaryon of this neuron, labelled axonal ramifications were seen in the neuropils of all ganglia except the pedals and right cerebral, and labelled axons occurred in seven nerve trunks. Electron microscopical examination of the perikaryon of the histamine neuron revealed the presence of large aggregations of granulated vesicles (80-200 microns diameter), elaborate endoplasmic reticulum, and numerous mitochondria, Golgi complexes and lysosome-like organelles.