The effects of irradiation on aggregate and pseudo-glomerule forming activity were studied quantitatively using dissociated kidney cells from new born mice. The dissociated cells formed macroscopic aggregates and microscopic inner structures, pseudo-glom erules, on the bottom of plastic dishes.
The inhibitory effects of irradiation on aggregation and pseudo-glomerule formation were detectable with a dose of as low as 10 R. However these abilities to form aggregates or pseudoglomerules were not completely lost even after irradiation with a dose of 1000R.

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Analyses of ruthenium-106 in marine environmental samples, which are useful for monitoring within a control context, have been developed. The quantity and the quality of the samples applied for the analyses are as follows : two l of sea water filtered through a millipore filter of 0.45 E.cm pore size; two g (wet weight) of bottom sediments prepared by sieving in sea water ; or the edible part of marine organisms equivalent to ca. 1 g ash. In order to equilibrate ¹⁰⁶Ru in the samples with ruthenium carrier and to dissolve the samples completely, marine organisms and sediments are ashed at 400-500°C, and then fused with a mixture of potassium hydroxide and potassium nitrate. Sea water is heated in the presence of an oxidant in an alkaline medium. Ruthenium is extracted with carbon tetrachloride as ruthenium tetroxide, and then back-extracted with sodium hydroxide solution containing a reducing agent. Hydrous ruthenium oxides are precipitated from the extract and subjected to β-activity measurement with a low background gas-flow counter by use of a 40 mg/cm² aluminum absorber. The loss of ruthenium throughout ashing and chemical procedures was found to be negligibly small by a tracer experiment. Chemical yields were 89±5 % and the ratio of chemical and radiochemical yields was 0.98±0.03. Sensitivity of the method (3σ) is 0.2 pCi and the whole chemical procedure takes 3 ?? 4 hours. Decontamination factors for the other activities were: > 3 × 10⁴ for ⁵⁴Mn and ⁵⁹Fe, 3 × 10³ for ⁶⁰Co, ⁸⁵Sr and ¹³¹I, 2×10³ for ¹³⁷Cs, 1×10³ for ⁶⁵Zn and ⁹⁵Zr-⁹⁵Nb, and approximately 10² for radionuclides of thorium and uranium series. A rapid γ-spectrometric technique for ¹⁰⁶Rh has also been developed in which ¹⁰⁶Ru was coprecipitated with cobalt sulfide from sea water.

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The losses of ¹³⁷Cs, ¹⁰⁶Ru-¹⁰⁶Rh, ⁶⁵Zn, ⁶⁰Co, ⁵⁹Fe, ⁵⁴Mn, ⁹⁵Zr-⁹⁵Nb and ¹⁴⁴Ce from the tissues of bivalves and green algae during dry ashing were investigated under the conditions of the temperature of 450, 550 or 800°C and the ignition time of 12, 24, or 48 hours.
Samples were prepared by rearing the organisms in sea water containing each radionuclide described above.
Biological tissues were decomposed in an electric muffle furnace. Recoveries of individual radionuclides in the tissues were calculated by the radioactivity ratio of pre and post-ashing of samples. Under the condition of 450°C, ignition was not complete in 24 hours for bivalves and in 12 hours for green algae.
The results of this investigation indicated that ¹³⁷Cs, ¹⁰⁶Ru-¹⁰⁶Rh, ⁶⁵Zn and ⁶⁰Co showed the loss in some ashing conditions and that the manners of the loss of these radionuclides were different between the organisms. ⁵⁹Fe, ⁵⁴Mn, ⁹⁵Zr-⁹⁵Nb and ¹⁴⁴Ce were not significantly lost under any condition used in this experiment. Accordingly, the loss of ¹³⁷Cs, ¹⁰⁶Ru-¹⁰⁶Rh, ⁶⁵Zn and ⁶⁰Co might be correlated with the biological matrix in which these radionuclides were incorporated, while there seemed to be no effect of biological matrix to the ashing loss of ⁵⁹Fe, ⁵⁴Mn, ⁹⁵Zr-⁹⁵Nb and ¹⁴⁴Ce.
The most desirable ashing condition in our investigation was 450°C, 48 hours for ¹³⁷Cs and 550°C, 12 hours for other radionuclides in bivalves, and 450°C, 24 hours for ¹³⁷Cs, ¹⁰⁶Ru-¹⁰⁶Rh and ⁶⁵Zn, and 550°C, 12 hours for other radionuclides in green algae.

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The transfer rate of radioactive cobalt to the eggs of hens and Japanese quails was investigated. No activity was found in the 1 st egg laid within 24 hours after oral dosing in the both species of birds. When ⁶⁰Co was given orally to the laying hens, the ⁶⁰Co content in the yolks became higher in the 2 nd and 3 rd eggs followed by a marked decrease with time. The cumulative amount of ⁶⁰Co in the hen's egg yolks for 14 days after oral dosing was estimated to be around 0.1% of the dose. In addition, the ⁵⁸Co content in the yolks was measured in the Japanese quails after single or daily intraperitoneal injection. It was found for the both modes of administration that the radioactive cobalt was mainly incorporated into the egg yolk, and very little to the albumen and shell, if any. Moreover, the whole-body retention of ⁵⁸Co was investigated after single or daily intraperitoneal injection in the Japanese quails.

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A new sulfhydryl compound, 2-mercaptopropionylglycine, which is commercially available in Japan as a detoxicating agent, has been shown to be protective in mice against lethal doses of ionizing radiation at a very low dose of 20 mg/kg, far below its toxic dose of more than 2, 000 mg/kg. The drug has an optimum dose for protection, 20 mg/kg, and its protection continues more than 3 hours, though with a less extent after 1 hour than within 1 hour. The results suggest a clue on the mechanism of sulfhydryl radioprotectors and give promise of clinical application.

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Anti-thrombocyte serum administered intraperitoneally to mice reduces thrombocyte count in 2 hours ; after 3 days the count starts to recover, reaching a maximum level on day 7 after the treatment. The injection of anti-thrombocyte serum before or after x-irradiation modifies not only the extent of radiation-induced thrombocytopenia of the treated animals but also their sensitivity against the lethal effect of x-rays.
The extent of thrombocytopenia on day 10 post-irradiation was minimized when the antiserum was administered to mice 2 hours or 1 day before irradiation (400 R). The survival rate of animal on day 30 was the highest when the antiserum was administered to mice 1 day before irradiation (750 R).
The results suggest that the modification of radiation lethality by anti-thrombocyte serum injection is resulted from the modification of thrombocyte dynamics.

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Amount of “spore photoproduct” (SP) was estimated by chromatography from ³H-labeled Escherichia coli DNA irradiated with 254 nm UV at -196°C. The amount of SP was greatly reduced by the presence of triplet state quencher manganese during irradiation. Magnesium which does not quench the triplet had no effect on SP formation. These results support the view that the excited triplet state of thymine, but not singlet state, is the precursor of SP.

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