Ascorbic acid protection against inactivation of lysozyme and aldolase by ionizing radiation. SAM-TR-65-71.
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Biomedical subjects
Publications and source records attributed to B Shapiro.
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The avidity of antibodies to DNA in the sera of 8 patients with SLE was determined by saturation analysis and Scatchard plots. Five of the patients had severe lupus nephritis; the other 3 had relatively mild or no kidney disease. The Scatchard plots revealed components with high relative avidity in the patients with severe nephritis (K values 4.4-10.4 X 10(5) M-1 for nDNA), compared with the patients who had mild or no kidney disease (K values 0.3-1.8 X 10(5) M-1 for nDNA). Avidity measurements may be helpful in the evaluation and treatment of patients with SLE.
The different diagnostic imaging modalities available for determining the location of the various APUDomas are discussed with reference to their advantages and disadvantages. The ability to image these lesions, and to be confident in their role in the underlying pathophysiology, and clinical neuroendocrine syndrome causing symptomatology and illness, has proved to be the key to successful treatment. In many instances it is not the diagnosis that is in question, but it is the extent of disease, the location of the lesion, or whether the anatomical abnormality under study is responsible for the complicating symptoms being considered, that are the crucial questions. The ability to locate APUDomas by a variety of direct and indirect imaging or regionalizing modalities, represent a magnificent advance in the management of these tumors. It should, however, be kept in mind that no one modality or diagnostic method can uniformly be relied upon. It is evident that a multimodal, interactive medical team approach is essential to the successful overall management of patients afflicted with these fascinating tumors.
Digital subtraction angiography (DSA) with a low injection rate of contrast (0.5 ml/sec) was studied as a means of predicting the regional perfusion of percutaneously placed catheters for hepatic arterial chemotherapy. In 64 hepatic artery catheter placements, conventional injection rate angiography (3-5 ml/sec) and low infusion rate DSA exams were compared to conventional radionuclide perfusion studies performed with Tc-99m-MAA. In 58 of 64 cases (90.6%) the conventional arteriogram correctly predicted the extent of hepatic perfusion, whereas in 63 of 64 cases (98%), the low flow DSA exam correctly predicted hepatic perfusion. The conventional arteriogram correctly predicted the extent of extrahepatic perfusion in 32 cases (50%), with a sensitivity of 100%, but a specificity of only 39.6%. The DSA exam was correct in defining the presence or absence of extrahepatic perfusion in 57 of 64 cases for a sensitivity of 82% and a specificity of 91%. Despite the quantitative difference between the low infusion rate DSA study and the chemotherapy infusion (10 ml/hr), it is a useful tool to assist in the correct positioning of temporary catheters for hepatic arterial chemotherapy.
OBJECTIVE: To determine the optimal clinical strategy utilizing either 1) serum catecholamines, 2) urinary metanephrines, or 3) urinary vanillylmandelic acid measurements in the evaluation of hypertensive patients with suspected pheochromocytoma. DESIGN: Prospective clinical determination of test-operating characteristics. SETTING: Tertiary care university medical center. PATIENTS/PARTICIPANTS: 415 patients referred for evaluation of suspected pheochromocytoma. INTERVENTIONS: All subjects had measurements of the three above-mentioned biochemical tests with the diagnosis of pheochromocytoma established by tissue confirmation. RESULTS: All three biochemical tests were similar in sensitivity (0.70-0.75), specificity (0.90-0.95), and receiver operating characteristics. With an estimated disease prevalence of 5.9% in symptomatic hypertensive patients, the predictive value of any single negative test would be 98% in ruling out disease. CONCLUSIONS: All three biochemical tests have similar performance characteristics and only a single test need be performed to exclude pheochromocytoma in most symptomatic hypertensive patients in a primary care population.
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GOALS: Determine the gastric emptying characteristics of a novel, 350-kcal test meal consisting of two muffins, using scintigraphy and the 13C-octanoate breath test (OBT). STUDY: Healthy volunteers underwent three studies on separate days within a 1-week period. On day 1, we measured emptying of the 350-kcal muffin test meal labeled simultaneously with 99mTc sulfur colloid and 13C-octanoate. On day 2, reproducibility of the OBT using a single-labeled 350-kcal test meal was assessed. On day 3, the effect of erythromycin on the 350-kcal OBT was determined. RESULTS: The mean (+/-SD) half-emptying time (T1/2) as measured by scintigraphy was 104 +/- 24 minutes, versus 212 +/- 52 minutes by OBT. There was a strong correlation between T1/2 determined by scintigraphy and the breath test (r = 0.83). Multiple linear regression analysis identified a significant relationship between T1/2 determined by scintigraphy and the 90-and 180-minute breath samples. There was a strong correlation (r = 0.830, slope = 0.732 +/- 0.120 [SE], intercept = 26.4 +/- 12.7) between the T1/2 obtained using the regression equation and the actual T1/2 obtained by scintigraphy. The mean T1/2 (+/-SD) for replicate determinations using the OBT was 209 +/- 52 minutes, compared with 196 +/- 42 minutes on days 1 and 2, respectively (not significant, p = 0.28, paired Student t test). Treatment with erythromycin on day 3 produced a significant decrease in T1/2 (155 +/- 49 minutes, p = 0.002). CONCLUSIONS: The 350-kcal muffin meal OBT provides a convenient, nonscintigraphic way of measuring solid-phase gastric emptying. Multiple linear regression appears promising as a method of analyzing OBT data and may allow for an abbreviated breath test protocol.
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Venous serum glucose concentrations determined by a laboratory hexokinase technique were compared over a wide range of glucose concentrations with concentrations of capillary blood glucose determined by three reflectance meter techniques currently available in the United States (Eyetone and Dextrometer, Ames Company; StatTek, Bio-Dynamics BMC) and by visual interpretation of reagent strips (Chemstrip bG, Bio-Dynamics BMC). The Chemstrip bG reagent strip was read by patients, nurses, and a physician. In all cases, there was an excellent correlation between laboratory serum glucose concentrations and reflectance meter blood glucose determinations (r = 0.90-0.94, P less than 0.0001) or visual interpretation of Chemstrip bG (r = 0.85-0.92, P less than 0.0001). Chemstrip bG appears to be the least expensive method of glucose measurement. This method offers additional advantages in not requiring a reflectance meter, which needs frequent recalibration and other ancillary equipment for blood glucose determination.