Radiolysis of dilute aqueous solution of dimethyl phthalate, DMP, with60Co γ-rays was investigated by using UV and IR spectrophotometric methods, gas chromatography, high-speed liquid chromatography. For both nitrogen- and oxygen-saturated solutions, an approximately linear relationship was held between the consumption of DMP and dose. The yield for the decomposition of DMP, G (-DMP), was 2.3 for the oxygenated and 1.6 for the deoxygenated solutions. The decomposition of DMP is initiated by the attack of hydroxyl radical on the benzene ring. Hydrated electrons, however, do not contribute to the decomposition. It was stongly suggested from the UV and IR spectral changes of DMP solutions induced by the irradiation that the elimination of the substituent on the benzene ring together with the ring cleavage reaction occur at rather early stages of the decomposition in the presence of oxygen. Organic acids such as formic, oxalic, and fumaric acids were identified as major products after the high dose irradiation of the oxygenated solution. The irradiation also gave rise to the significant reduction in the total organic carbon (TOC) in the presence of oxygen. The reduction of TOC was nearly the same as the amount of CO2produced, indicating that in the presence of oxygen, DMP is completely decomposed by radiation into CO2.
To know what kinds of the cell components of Chlorella regularis are concerned with uranium binding, uptake of uranium by various cell fractions was examined. The uptake value (μgU/mg starting dry cells) of the hot water-treated cells was almost the same as that of the starting dry Chlorella cells, showing that the cell components extracted with hot water were not so concerned with uranium binding. The cell components extracted with dilute alkali seemed to play an important role in uranium binding, and those extracted with chloroform-methanol seemed to be partly concerned with uranium binding. The cellulose fraction of the cells was scarcely concerned with uranium binding. In the dry cells, 34% of uranium taken up existed in the cell walls. However, in the living cells, 85% existed in the cell walls. The above results showed that the dry or the hot water-treated cells are the most convenient for uranium recovery from the aqueous systems.
We estimated the enzyme activities on the hexose monophosphate oxidative pathway of glucose metabolism at an early stage during feeding with 3'-methyl-4- (dimethylamino) azobenzene (3'-Me-DAB) in the first paper of this series. In the present paper, the importance of this non-glycolytic pathway of glucose metabolism in preneoplastic liver in azo-dye fed rat was studied by radiorespirometry using [1-14C] glucose and [6-14C] glucoce. In addition to radioisotope analysis, the level of activity of glucose-6-phosphate dehydrogenase was measured in rat liver after various periods of feeding with 3'-Me-DAB. In radiorespirometry using [1-14C] glucose, the peak time was delayed up to the 2nd week, but was early by the 4th week and was the same as the control at the 5th week and thereafter. On the other hand, the peak height and the yield value both changed in almost the same way. That is to say, they were lower than those of the control until the 2nd week, began to increase from the 3rd week, reached a maximum at the 4th week, and remained at the control level at the 5th week and thereafter. Moreover, the yield value ratio of respiratory14CO2from [1-14C] glucose to that from [6-14C] glucose increased from 1.3 to 1.52 at the 3rd to 4th week after feeding with 3'-Me-DAB. The activity of glucose-6-phosphate dehydrogenase increased as early as the 2nd week after the start of feeding with 3'-Me-DAB, reaching a maximum at the 4th week. Thereafter, the activity remained high with a slight decrease from the maximum by the 6th week. The incorporations of [3H] thymidine and [U-14C] glucose into rat liver DNA at the 4th week after feeding with 3'-Me-DAB were both as high as 2 to 4 times those of the control.
Single photon radioisotope computed tomography (RCT) images were obtained using the following devices such as conventional gamma camera, data processer for exclusive use of nuclear medicine (C.D.S.-4096), magnetic tape and medium size electronic computer FACOM 230-28S (48K) for multipurposes, which are routinely used for clinical purpose. To reconstruct the RCT image we made absorption correction by geometric mean of opposing counts considering the thickness of source and used the convolution integral method. The reconstructed images of phantom study resolved one centimeter clearly and were very similar to original. The RCT image of patient was acquired by the rotation of patients using the revolving chair and the handmade implement which settles the center of patient's head. Three dimensional informations were obtained by one examination with a gamma camera which collects two dimensional images. When using a gamma camera, therefore, not only a transaxial but an arbitraly RCT image will be important to contribute for diagnosis.
A detailed comparison was performed subjectively and objectively between the quality of cardiac pool images obtained using red blood cells lebeled in vivo with99mTc and99mTc-human serum albumin. Both methods gave cardiac pool images of high quality. In order to compare the images between both methods, the microdensitometry was performed in both images of the same patients along the line drawn through the center of the left ventricular image and the septal image. Measuring the highest density of left ventricle as CL and that of septum as Cs, the index I (II) was obtained as (CL-Cs) and the index II (II) was calculated as (CL-Cs) / (CL +Cs) . The objective comparison was performed by these indices. The method using red blood cells labeled in vivo with 99mTc resulted in subjectively superior images and a higher left ventricle-to-septum density ratio in cases of control groups, myocardial infarction and aortic valvular disease. But in cases of mitral valvular disease and arrhythmia the in vivo method resulted in inferior or almost equal to the method obtained using99mTc-HSA. The quantitative indices used in this study can be thought to represent the contrast between the left ventricular image and the septal image. A better contrast may be obtained in a better image and may contribute more to the clinical diagnosis. From the point of clinical contribution, both agents are suitable for radionuclide imaging of the cardiac chambers. And the adequate combination of both method may be useful for clinical diagnosis.