PF塑料吸附富集与AAS法测定微量铊

提出简便、快速、灵敏的AAS法测定铊。采用聚氨脂泡沫（PF）塑料吸附富集铊，大量的金属离子和阴离子完全不干扰。此法用于测定矿石、钼精矿和铜精矿中微量铊，获得了满意的结果。     

Superiority of nitrate-enhanced 201Tl over conventional redistribution 201Tl imaging for prognostic evaluation after myocardial infarction and thrombolysis

BACKGROUND: 201Tl imaging has been widely used for postinfarction risk stratification. However, thrombolytic therapy and aspirin have significantly changed outcome, and there are few nuclear imaging studies that assess prognosis in such patients. Furthermore, newer techniques of 201Tl imaging, such as reinjection and nitrate-enhanced rest 201Tl imaging, have been shown to improve the detection of viable but jeopardized myocardium. METHODS AND RESULTS: We studied 100 consecutive patients, who remained event free 6 weeks after myocardial infarction and thrombolysis. Patients underwent conventional exercise and 4-hour redistribution imaging, followed on a separate day by nitrate-enhanced rest 201Tl study. Planar images were reported semiquantitatively by two experienced observers blinded to clinical data. Redistribution and rest injection images were classified as demonstrating reversible ischemia if they showed improvement in uptake by at least two grades in at least two segments in comparison with the initial exercise scintigram. Patients were followed up for 8 to 32 months (mean, 21 months); during this period, 37 patients had first cardiac events. Reversible ischemia was present in 29 patients on redistribution, of whom 14 (48%) had events; of 71 without reversible defects, 23 (32%) had events (hazard ratio, 1.5; 95% CI, 0.8 to 3.0; P=NS). Nitrate-enhanced rest 201Tl imaging detected reversible defects in 68 patients, of whom 33 (49%) had events, whereas of 32 without reversible defects, only 4 (13%) had subsequent cardiac events (hazard ratio, 8.1; 95% CI, 2.7 to 23.8; P<.001). CONCLUSIONS: Thus, after myocardial infarction and thrombolysis, even "stable" patients have a high (68%) incidence of viable but jeopardized myocardium, causing a high event rate. Those identified to be at high risk by perfusion imaging may benefit from early intervention.     

Tl2SO4的研制

采用硫酸溶解、自然重结晶方法制备Tl2SO4。     

Is 201Tl a reliable agent in tumour imaging?

Periodontal health states are difficult to quantify and no formal scale quantifying patients' utilities for periodontal health states exits. Multi-attribute utility (MAU) techniques were used to develop such a scale. The MAU scale may be used to quantify patients' assessment of their current periodontal health and that of possible treatment outcomes. Such data, combined with probability values in formal decision analysis techniques would result in improved rationality of treatment planning for periodontal disease. 20 patients attending for routine undergraduate care were interviewed. Data from these interviews were sorted into groups of common interest (domains). Intra-domain health statements were complied from the interview content. 21 patients ranked the intra-domain statements on a scale of 0-100. This same group of patients also performed an inter-domain weighting. Mean results showed that patients were 2X as concerned with how they felt and with the prognosis of possible outcomes, than with how they looked and what facts they knew about their oral health. However, the real value of utilities research lies in application of individual results to treatment planning as there is a wide range of opinion regarding outcome health states.     

Diagnosis of lung cancer using functional image of 201Tl SPECT with parameter of 201Tl retention--evaluation of its applicability to post irradiated lung cancer

Thallium-201 (201Tl) SPECT is a useful method for detecting lung cancer. Moreover, the 201Tl Retention Index (R.I.) reported by Tonami et al is now available for differentiating pulmonary lung cancer from benign lesions. The diagnosis of recurrent tumors is, however, difficult to establish as they are often shaded by radiation pneumonitis or fibrosis. Therefore, we employed functional images (F.I.) obtained using as parameter a modified version of the R.I. First we indicated the statistical value of untreated solitary lung tumor as follows: sensitivity 84.6%, specificity 80.0%, and accuracy 83.3%. In our assessment, the lesions with tumor size over 2.0 cm and R.I. by Tonami et al over 12.7 were detected as positive images. Secondly in assessment of 22 cases (23 lesions) of post irradiated lung cancer, the results obtained were: sensitivity 80.0%, specificity 92.3%, and accuracy 87.0%. 201Tl SPECT functional images seem to be useful for the diagnosis of recurrent lung cancer by shaded radiation pneumonitis and fibrosis.     

Conformational changes in yeast pyruvate kinase studied by 205Tl+ NMR

The interaction of the monovalent cation with yeast pyruvate kinase (yPK) has been investigated by 205Tl+ NMR. TlNO3 activates yPK to 80-90% activity compared to KCl with an apparent Ka of 1.00 +/- 0.03 mM in the presence of 4 mM Mn(NO3)2 as the activating divalent cation. At higher concentrations of Tl+, enzyme inhibition is observed with an apparent KI of 180 +/- 10 mM. The extent of inhibition is dependent on the nature and concentration of the divalent cation. The effect of Mn2+ on the 1/T1 and 1/T2 values of 205Tl+ in the presence of yPK was determined at 173.02 MHz (300 MHz, 1H) and 346.03 MHz (600 MHz, 1H). The temperature dependence of the relaxation rates indicates that fast exchange conditions prevail for 205Tl+ longitudinal relaxation rates. The correlation time, tauc, for the Mn2+-205Tl+ interaction was estimated by a frequency dependence of 1/T1m for several enzyme complexes, and an average value of tauc was determined to be 0.91 ns. The distance between Tl+ and Mn2+ at the active site of yPK was calculated from the paramagnetic contribution of Mn2+ to the longitudinal (1/T1m) relaxation rates of Tl+ bound to yPK. For the apo yPK complex, the Tl+ to Mn2+ distance is 6.7 +/- 0.2 A. Upon addition of phosphoenolpyruvate (PEP) to form the yPK-Tl-Mn-PEP complex, the inter-cation distance decreases to 6.1 +/- 0.3 A. The addition of the allosteric activator fructose 1,6-bisphosphate (FBP) to form the yPK-Tl+-Mn2+-PEP-FBP complex gives an intermetal distance of 6.2 +/- 0.2 A. In the yPK-Tl-Mn-FBP complex, a Tl+-Mn2+ distance of 6.0 +/- 0.1 A is observed, indicating that FBP causes a conformational change at the active site in the absence of PEP. Analogous 205Tl NMR experiments with competitive inhibitors of PEP (oxalate, BrPEP) indicate that these ligands do not induce the same conformational changes as do the physiological substrates and activators. Similar experiments with the nonallosteric rabbit muscle PK were also performed and analyzed.