Radionuclide angiography was used to generate first-pass radioactivity vs. time curves for the left heart, right hepatic lobe, right lung, spleen, and both kidneys following rapid intravenous injection of 20 mCi (740 MBq) of 99mTc-pertechnetate. Seven normal subjects were examined as well as 57 cirrhotic patients, who also underwent angiographic grading of portal venous perfusion. For analysis, two time points were identified: (a) t0, when 99mTc first entered the liver (the initial rise of either curve); and (b)tc, when 99mTc was maximal in abdominal organs (the renal peak). Analysis was based on the slopes of the two phases of the hepatic curves t0 + 7 seconds and Tc + 7 seconds; this time selection permitted analysis of all curves. The hepatic perfusion index (HPI) = slope (tc + 7 secs)/slope (t0 + 7 secs) + slope (tc + 7 secs). The mean HPI for the normal subjects was 66% +/- 7; for the cirrhotic patients with angiographic Grades I, II, III, and IV, the HPI was 52% +/- 9, 37% +/- 6, 15% +/- 7, and 3% +/- 4, respectively. Correlation between HPI and angiography was significant (p less than 0.001). This method offers a readily available, rapid, relatively inexpensive, and quantitative method of grading the ratio of portal venous to total hepatic blood flow.
The measurement of portal venous flow to the liver is important in the evaluation of patients for shunt surgery. A previous report described a method using slope analysis of hepatic radionuclide angiograms to generate an index of relative portal flow, which correlated well with angiographic grades of portal perfusion. The present report describes a refinement in bolus administration and a modification in technique that appear to reflect true portal venous flow more accurately. A total of 109 studies was performed, including seven normal and 80 cirrhotic patients. The method was reproducible (r = 0.998) and showed good correlation with the angiographic grades of perfusion (r = -0.906).
This enzyme-radioimmunoassay for the measurement of L-dopa, dopamine, and 3-O-methyldopamine is based on the incubation of urine in the presence of catechol-O-methyltransferase, aromatic-L-amino-acid decarboxylase, and S-adenosylmethionine. The O-methylated dopamine metabolite formed, 3-O-methyldopamine, was characterized by radioimmunoassay. To evaluate the role of L-dopa metabolism in melanoma, we used the enzyme-radioimmunoassay to assess concentrations of L-dopa, dopamine, and 3-O-methyldopamine in urine from 10 healthy subjects, 10 hospitalized patients without melanoma and 28 patients with different degrees of melanoma. The effect of surgery for melanoma on urinary output of these catechols of melanoma patients was also evaluated. No significant difference in urinary L-dopa, dopamine, and 3-O-methyldopamine excretion rates was seen between normal subjects (L-dopa 1.3 +/- 0.3, dopamine 147 +/- 38, and 3-O-methyldopamine 31.4 +/- 13.6 microgram/24 h), hospitalized patients without melanoma, and amelanotic melanoma patients. However, the excretion rates for these metabolites in melanotic melanoma (L-dopa 5.6 +/- 1.2, dopamine 555 +/- 121, and 3-O-methyldopamine 178 +/- 40.3 microgram/24 h) were significantly (p < 0.005) higher than in control or amelanotic melanoma subjects. After surgery, there was a substantial decrease in urinary output of L-dopa and its metabolites by these patients.
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