(1) In the case of estradiol diacetate, treatment of the thallation product with [125I]NaI, using the same reaction conditions, gave exclusively the 2-iodo isomer.
(2) The method of radiolabelling, based on the thallation of compound (5) and the subsequent treatment with radioiodide, resulted in a regioselective radioiodination with a 54% radiochemical yield.
Thallium
Definition:
(n.) A rare metallic element of the aluminium group found in some minerals, as certain pyrites, and also in the lead-chamber deposit in the manufacture of sulphuric acid. It is isolated as a heavy, soft, bluish white metal, easily oxidized in moist air, but preserved by keeping under water. Symbol Tl. Atomic weight 203.7.
Example Sentences:
(1) Thallium-201, a radiopharmaceutical that possesses many of the characteristics of potassium analogues, at present is receiving the greatest attention as a regional blood flow indicator.
(2) Distant ischemia was distinguished from peri-infarctional ischemia by the presence of transient thallium defects in, or slow thallium washout from myocardium not supplied by the infarct-related coronary artery.
(3) In 89 patients, a symptom-limited exercise electrocardiogram (ECG) and thallium scintigraphy were performed 4 weeks after they had undergone successful PTCA.
(4) The results of quantitative analysis of planar thallium-201 stress scintigraphy are superior to those of visual analysis.
(5) Qualitative planar 201-thallium (201Tl) scans, coronary angiography, or both were also performed (median between studies 11 days).
(6) Eight of 16 patients with thallium redistribution had cardiac events, whereas there were no such events in 32 patients whose thallium scan either was normal or showed only persistent defects (P less than 0.0001).
(7) A method of poisoning cats with thallium is described.
(8) Normal thallium uptake on single photon emission computed tomographic scintigraphy early in the hospital course predicted myocardial viability in the region of the aneurysm.
(9) Before surgery, 15 patients had myocardial perfusion defects during exercise that completely normalized at rest, one patient had both reversible and fixed perfusion defects, two patients had fixed defects only, and two patients had normal exercise and rest thallium scans.
(10) This analysis suggests that the reported sensitivity of thallium scintigraphy is higher and the specificity lower than that expected in clinical practice because of the presence of workup bias and the inappropriate inclusion of post-infarct patients.
(11) Thus, estimation of total % thallium uptake is a simple index which yields useful diagnostic clinical information.
(12) When combined with atrial pacing, 2-D echocardiography and thallium 201 perfusion imaging are of similar value for diagnosing the presence of CAD in patients with stable chest pain.
(13) We evaluated the role of thallium-201 single-photon emission-computed tomography (SPECT) in diagnosis, differential diagnosis and follow-up of 33 patients with primary brain tumors.
(14) By contrast, in 11 patients with no previous myocardial infarction and normal left ventricular function at rest (Subgroup B), initial uptake of both tracers was inverse: poststenotic N-13 glutamate uptake increased with decreasing thallium-201 uptake during exercise-induced ischemia (r = -0.64, p less than 0.05) and was closely correlated with the percent thallium-201 redistribution (r = 0.74, p less than 0.01).
(15) This subset of patients showed the least dynamic anterior wall contraction (P less than 0.001) and the highest incidence of thallium-201 perfusion defects (P less than 0.05) and of recurrent cardiac arrest (P less than 0.05).
(16) Thallium imaging was much more likely to be positive (p less than 0.01) in patients with a cardiac complication; however, there was a significant number of patients with cardiac complications who had a positive history or electrocardiogram for myocardial infarction.
(17) Intravenous dipyridamole-thallium imaging unmasks ischemia in patients unable to exercise adequately.
(18) Over a two year period, 67 patients undergoing carotid or aortic surgery were investigated preoperatively with dipyridamole-thallium scan.
(19) Morphometric analysis of hepatocytes from thallium-treated rats disclosed a 3-fold increase in the volume density of the lysosomal compartment and a 1.3-fold increase in the volume density of mitochondrial.
(20) Segmental analysis of the planar thallium-201 images was performed in a blinded fashion with agreement by consensus.