Cobalt-57-bleomycin (BLM) has been proven to be the most stable and useful tumor-diagnostic agent among several radiolabelled BLMs. However, the considerably long half life of57Co causes troubles in handling and preclude its extensive uses. In our previous work, BLM was proved to form two geometrical isomers, in chelating with Co. In this paper, we compared the tumor affinity of two isomers, to make an improvement of this drug's merit. We investigated biodistribution in tumor-bearing mice and DNA binding properties by fluorescence quenching technique and DNA melting study. A comparison of the data obtained suggests that isomerism affects the tumor affinity of the drug. Both tumor accumulation in tumor-bearing mice and stability of DNA binding of type I isomer were higher than those of type II. If a certain suitable radionuclide is inserted into cold Co-BLM type I isomer, this agent will be a greatly useful tumor-imaging radio-pharmaceutical.
In order to evaluate201Tl-accumulation in lung, 201Tl imaging was performed using a scintillation camera coupling to a small digital computer, and blood clearance of it was examined. After the injection of 74 MBq (2mCi) of201Tl-chloride, the serial images and static images were obtained. In order to obtain the image of201Tl in the extravascular space [TE (x, y) ], a subtraction technique was performed as follows; after 2 anterior views of201Tl were obtained using a 20% window centered at 80 keV [T0 (x, y) ] and 140 keV [T140 (x, y) ] respectively, and blood sample was taken, radionuclide angiocardiography with 185 MBq (5 mCi) of99mTc-human serum albumin and it's static image were done in the same supine position and blood sample was taken too. The radioactivity of201Tl (T) and99mTc (HB) in the blood was counted by a autogamma scintillation counter. Then the image of TE (x, y) was obtained by the following formula; TE (x, y) =T0 (x, y) - [H (x, y) -T140 (x, y) ] TB/HB. Following results were obtained; (1) The disappearance of201Tl from the blood was rapid and 15 min after the injection only 10-15% of the activity after 1 min was present in the blood. (2) The lung activity in the time activity curve decreased rapidly to reach plateau within 100-150 sec after the injection. (3) The image of201Tl in the extravascular space was nearly equal to the original one as regard to the radioactivity of201Tl in lung.
Total cortisol and progesterone in the maternal peripheral sera were determined by radio-immunoassay. Total cortisol was measured in 196 sera, and progesterone in 203 sera obtained randomly throughout pregnancy. And serial estimations of both steroid hormone levels were also made simultaneously in 6 normal pregnant women during late pregnancy, labour and puerperium. Total cortisol and progesterone increased with the advance of gestation. During the last few weeks preceding labour total cortisol increased further, whereas progesterone decreased. After the onset of labour a rising tendency in total cortisol levels and a falling tendency in those of progesterone were also observed, but at puerperium both hormones decreased rapidly to non-pregnant level in the 6 pregnant women.
A radioimmunoassay for dihydroergotoxine was developed using antiserum from the rabbit injected with a dihydromethylergometrine-bovine serum albumin conjugate. The antiserum was found to be highly specific to dihydroergot alkaloids. The minimum detectable amount of dihydroergotoxine methanesulfonate with this assay system was about 100 pg/ml in serum. Practical applicability of the assay system was proved by measuring dog serum concentrations after oral administration of dihydroergotoxine methanesulfonate.