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Biomedical subjects

M W Burke

Publications and source records attributed to M W Burke.

17 recordsLinked to original sources
PubMed1992

Acute lower gastrointestinal hemorrhage: treatment by superselective embolization with polyvinyl alcohol particles.

OBJECTIVE: The major risk of transcatheter embolotherapy for acute hemorrhage in the lower gastrointestinal tract is irreversible intestinal ischemia. The authors studied the efficacy and safety of superselective transcatheter embolization with polyvinyl alcohol particles in arresting acute hemorrhage in the lower gastrointestinal tract. SUBJECTS AND METHODS: All patients with clinical or scintigraphic evidence of acute hemorrhage in the lower gastrointestinal tract were considered for superselective embolization. The nine patients with angiograms that showed active hemorrhage in the lower gastrointestinal tract underwent the procedure. Superselective embolization was done through a 3-French catheter and was accomplished by using 100- to 590-microns polyvinyl alcohol particles. The segments of the intestinal tracts involved in the embolizations were examined for the presence of ischemia by endoscopy (n = 7) or histologic evaluation of a surgical specimen (n = 2) 2-44 days (mean, 11 days) after embolization or by clinical evaluation (n = 1). RESULTS: The lesions treated by this method were located in the colon (n = 8) and jejunum (n = 1). Immediate hemostasis was achieved in every case. Three patients had recurrent lower gastrointestinal hemorrhage 1-24 days (mean, 9 days) after initial embolization. Two of these patients had surgery, while one had a successful second embolization. Two asymptomatic patients were found endoscopically to have small areas of ischemia involving only the mucosa. Only one patient was shown to have severe mucosal ischemia; this involved the colon in a distribution that suggested it was not caused by the embolization. CONCLUSION: Ten superselective embolization procedures that used polyvinyl alcohol particles successfully controlled hemorrhage in the lower gastrointestinal tract in nine patients. In no case was intestinal infarction induced by the procedure, and only two endoscopically proved cases of asymptomatic mucosal ischemia occurred.

Acute Disease↗
PubMed1988

Treatment of massive acute pulmonary embolism. The use of low doses of intrapulmonary arterial streptokinase combined with full doses of systemic heparin.

The efficacy of low-dose, locally administered streptokinase (SK) combined with full therapeutic systemic doses of heparin was investigated. Seven patients with angiographically proven massive acute pulmonary embolism were treated. Streptokinase, 10,000-20,000 units/hour, was administered directly into the left or right pulmonary artery for 9 to 24 hours. Heparin was administered concurrently. The number of unperfused segments of the infused lung shown on the lung scan decreased from 5 +/- 2 to 2 +/- 1 after 12-24 hours (p less than .01). No change was shown in the contralateral lung. The angiographic index of severity score in the infused lung decreased from 16 +/- 1 to 9 +/- 4 (p less than .01). The partial pressure of oxygen in arterial blood improved within four hours. In spite of the low doses of streptokinase, however, two major bleeding episodes occurred that required blood transfusion. In conclusion, low dose intrapulmonary streptokinase, combined with intravenous heparin, may provide a therapeutic option in patients with life-threatening massive acute pulmonary embolism in whom full dose lytic therapy may be hazardous, although even low dose lytic therapy was associated with risk.

Aged↗
PubMed1988

Detection of malignant melanoma with monoclonal antibodies.

Eleven murine monoclonal antibodies (MoAbs) were isolated that defined unique membrane antigens expressed on human melanoma cells but not detectable on human lymphoid cells by radioimmunometric assays. Five of these MoAbs each identified a separate melanoma cell surface antigen as shown by distinctly different in vitro MoAb binding patterns to a diverse panel of tumor cell lines. One of these 5 monoclonals, MoAb 34.1, reacted specifically with 9/11 melanoma lines and 0/28 other human tumor or lymphoid cell lines. The other 4 MoAbs reacted strongly with melanomas, but also bound to 1 or more non-melanoma lines. The remaining 6 MoAbs defined three distinct regions of a single melanoma cell membrane protein with a molecular weight of 125 kiloDaltons (kD) as shown by antibody crossblocking and gel electrophoresis. A sensitive radioimmunoassay developed with MoAbs to 2 epitopes of this 125 kD protein detected up to 500-fold higher levels of this antigen in extracts of melanoma cells compared to autologous lymphoid cells. The 125 kD antigen also was detected by indirect immunoperoxidase assays with the MoAbs on biopsied tumors in histologic tissue sections of 5/11 metastatic melanomas and 1/11 carcinomas but was found on some normal endothelium and smooth muscle. Another monoclonal, MoAb 705, reacted more broadly with tumor cells in 10/14 biopsied melanomas and 10/11 carcinomas, but also was reactive with basal epidermis and normal fibroblasts. By contrast, MoAb 34.1 bound specifically to tumor cells of 7/11 biopsied metastatic melanomas, but bound 0/10 carcinomas and few normal tissues except for some macrophages. Thus, MoAb 34.1 was the most specific diagnostic reagent for immunohistologic detection of melanoma. The 250 kD antigen defined by MoAb 34.1 is similar to a high molecular weight proteoglycan reported to be an excellent tumor marker for human melanomas. The results of these studies show that murine monoclonal antibodies can be used as sensitive reagents for radioimmunoassays and immunohistology of malignant melanoma.

Animals↗
PubMed1987

Eigenimage filtration of intravenous digital subtraction angiograms of the heart. Work in progress.

The authors developed a postprocessing technique, eigenimage filtering, to extract phase-dependent information from digital subtraction angiograms of the heart. This technique suppresses the interference from the right ventricle and left atrium and produces an image of the left ventricle and aorta that is substantially free of these overlap artifacts. The resultant eigenimages of the heart appear more like conventional ventriculograms than do digital subtraction angiograms and matched filtered images.

Cardiac Catheterization↗
PubMed1987

Portal hypertension workup by DSA.

To provide information for preoperative planning, combined, selective intravenous (IV) and intraarterial (IA) digital subtraction angiography (DSA) studies were performed on 42 portal hypertension patients scheduled for portal systemic shunt procedures. Selective IV-DSA was performed to demonstrate the hepatic venous system, left renal vein, and inferior vena cava. Portal venous anatomy, direction of flow, and portal systemic collaterals were evaluated by selective IA-DSA. In addition, selective IA-DSA was performed postoperatively on 8 patients to assess shunt patency. Technically adequate DSA studies, suitable for surgical planning or postoperative assessment, were obtained in all of the 50 patients examined. Patient or internal organ motion was not a limiting factor in any study. Such use of DSA represents an efficacious, safe, and cost-effective alternative to conventional film-screen angiography for the evaluation of patients with portal hypertension.

Angiography↗
PubMed1986

Breast lesions: differential diagnosis using digital subtraction angiography.

To evaluate its potential for differentiating benign from malignant breast lesions, digital subtraction angiography of the breast (DSAB) was performed in 23 women with mammographic evidence of disease, and the results were compared with surgical biopsy findings. The DSAB technique employed breast immobilization with modest compression and bolus injection; following the injection of contrast material, 30-40 sequential subtraction images were obtained over a 5-minute interval. The average technical settings were 50 k Vp and 10 mAs, resulting in an estimated radiation dose to the breast of 0.05 mrad (0.5 mu Gy) per exposure. DSAB consistently demonstrated retention of contrast material and abnormal vasculature in malignant lesions but not in benign lesions. In the 22 breast lesions for which there was histopathologic correlation, DSAB correctly categorized eight of nine malignant and 11 of 13 benign lesions. Although this series is small, the initial results of DSAB suggest its potential for differentiating benign from malignant lesions.

Adenocarcinoma↗
PubMed1986

Superior vena cava obstruction: evaluation with digital subtraction angiography.

Superior vena cava (SVC) obstruction is an uncommon but dramatic clinical presentation that often requires immediate treatment. We present a technique for evaluation of SVC syndrome using small-gauge butterfly needles and intravenous digital subtraction angiography, and we report our results in ten patients. We find this technique superior to conventional venography since it is rapid, easy, safe, and more cost-effective to perform.

Adult↗
PubMed1979

Stimulus similarity and order as factors in visual short-term memory in nonhuman primates.

The short-term retention of nonhuman primates for a single sample or for two successively presented samples was assessed in four delayed matching-to-sample experiments with delays of .03, 4, 8, 16, and 32 sec. The single sample tasks included one (Experiment 1) or two (Experiment 4) distractor stimuli in the choice set (matching test). In the two successive samples tasks, the animals matched (reconstructed) the order of presentation of two samples with (Experiment 3) and without (Experiment 2) a distractor stimulus. Also, the possible combinations of eight stimuli (four colors and four shapes) were arranged to test the effects of sample set and choice set similarity. Taken together, analyses of the errors indicated that both sample and choice set similarity were significant sources of confusions in delayed matching. Order errors occurred independently of similarity but were a source of forgetting primarily at the longest delays (16 and 32 sec). Two exceptions to the similarity effect (second response errors in Experiment 3 and errors of an inexperienced group in Experiment 4) were observed. Possible reasons for the exceptions and several implications of these findings for theories of short-term memory are discussed.

Animals↗