The formation of organic iodine by reactions of iodine released from irradiated U3O8with several materials such as air, CO2, H2O, CH4, and C4H10and of vaporized AgI with such ones as air, CH4, and CH3OH was preliminarily studied. The formation of the organic iodine was noticed in both cases when the iodine released from the irradiated U3O8reacted with CH4 or C4H10gas and when the AgI did with CH4gas or CH3OH vapor. The yield of the organic iodine increased with increases in reaction time and the gas concentration. It was found in case of the irradiated U3O8that the organic iodine was formed predominantly by a gas-solid reaction between CH4gas and the iodine deposited on the wall of the reaction space rather than by a gas phase reaction between released iodine in vapor state and the gas. The yield of the organic iodine increased with increase in the decomposed fraction of the uranium iodide released from the irradiated U3O8or the vaporized AgI. In cases of air, H2O, CO2, the organic iodine formation was thought to be suppressed.
The Res-O-Mat T4test system is one of in vitro methods for the determination of total thyroxine in serum. The authors reviewed in many respects the conditions of measurement by Res-O-Mat T4kit using 300 and over subjects as follows: 1. Radioactivity of each incubation vial, 2. Effect of incubation time, 3. Effect of temperature of incubation, 4. Effect of extraction alcohol, 5. Effect of gradient of standard curve, 6. Fluctuation of T4values, 7. Effect of rotation speed, 8. Determination of T4values above 18μg%, 9. Each T4value of euthyroid, hypothyr'oid and hyperthyroid, 10. Comparison with Triosorb test or Tetrasorb test. The Res O Mat T4test has been proved to be valuable as clinical thyroid function test.
Astudy to assess relative accuracy of the results of Res-O-Mat T3test in correlation with several conventional thyroid function tests was performed. 1) Scatter of radioactivity in vials of each kit was within three per cent; this indicates remarkably high homogeneity (Table 1) . 2) Assay errors; The difference between TBC indices of two serum samples of each case averaged 0.04, thereby indicating fairly small errors in assay (Table 2) . 3) Effect of various lengths of incubation time; When the incubation temperature was not lower than 25°C, there were no significant differences between the assay results obtained with one-hour incubation and two-hour incubation. When the incubation temperature was about 20°C, there were significant differences between assay results of the one-hour and two-hour incubations. 4) Normal range of TBC index; The TBC index ranged from 0.87 to 1.07 with an average of 0.98 in the group of euthyroid individuals, from 0.58 to 0.87 with an average of 0.75 in the group of hyperthyroid patients, and from 1.02 to 1.34 with the mean index of 1.21 in the group of hypothyroid state. The normal range, accordingly, was considered to be 0.85-1.10. 5) Correlation between the TBC index and the Triosorb results; A fairly good correlation was observed between the TBC index and the Triosorb assay results. The data support the feasibility of the use of Res-O-Mat T3test system as a simple routine diagnostic tool for assessment of thyroid function.