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Volume 4, Issue 2-4
Displaying 1-10 of 10 articles from this issue
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Masanao HOSOE, Sayo CHIN, Eizo TAJIMA1963 Volume 4 Issue 2-4 Pages 59-67
Published: 1963
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSThe limitation of Fano's “Theorem of homogeneity” was investigated using homogeneous medium CH2 under irradiation of X-rays. Variations of ionization current with the pressure of ethylene gas in a parallel plate polyethylene chamber were observed. The nonlinearity obtained in the I-P curve, ionization current vs. pressure of gas, was attributed to the deviation from the assumption of the theorem. This deviation is considered to be due to the effect of chemical aggregation on the behaviour of slow electrons.View full abstractDownload PDF (360K) -
Studies on Radiation Dosimetry by a Solid Color Changing Substance (Solid Color Radiation Dosimetry)Masaru WAKABAYASHI, Goro IRIE, Shigeru SHIBATA, Sueo KAWANISHI, Kazuo ...1963 Volume 4 Issue 2-4 Pages 68-79
Published: 1963
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSA study on the solid chemical dosimeter was made to improve the sensitivity to x-ray and the stability to ultravioletray. According to the results obtained with gelatin, cellulose, plastic, paraffin and fat, the best material as a base was as paraffin. The small amount of vaseline was added into paraffin to prevent the crack and flake forming.
The results of the screening of about 100 dyes showed that methyl yellow was the best dye of those to detect the effect of x-ray irradiation in chloroform-paraffin system. Dinthizon was sensitive dye in carbon tetrachloride-paraffin system.
Many kinds of organic or inorganic compounds were blended into the chloroform-paraffin-vaseline system to sensitive the response to ionizing radiation and stabilize to ultravioletray. Para-hydroxy azo benzene was most effective as a sensitizer and stabilizer. Several halogenated hydrocarbons were mixed into the methyl yellow-paraffinvaseline system to check the degree of color change produced by x-ray irradiation, and it was found that chloroform was the best of these for methyl yellow system.
From these experiments, the practical dosimeter was made by mixing of methyl yellow, p-hydroxy azo benzene, paraffin and vaseline. Three methods with electric, optical and pH meter were tried in order to measure the amount of chemical products in the dosimeter, but the measurement with pH meter was most applicable. The amount of acid produced by x-ray irradiation was directly proportional to the exposure dose up to 5000 r. The multi color changes proportional to changed dose were made by the combination of dithizon and methyl yellow added into carbon-tetrachloride-chloroform mixture.View full abstractDownload PDF (562K) -
Shigefuini OKADA1963 Volume 4 Issue 2-4 Pages 80-84
Published: 1963
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSThe mechanisms of inactivation of deoxyribonuclease by direct action of radiation have been studied. By testing kinetic properties of the enzyme and its tryptophan content, it seems likely that when the enzyme molecule absorbs energy from radiation, the energy is transferred to the ‘active site’ of the enzyme. This results in the degradation of one tryptophan residue, which, in turn, causes a loss of catalytic function of the enzyme. The differences between indirect and direct actions are also discussed.View full abstractDownload PDF (221K) -
Terutoshi YAMASAKI, Takashi ITO, Yoriaki MATSUDAIRA1963 Volume 4 Issue 2-4 Pages 85-90
Published: 1963
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSIn the hope of obtaining the genetic multiplicity of the ad gene in yeast cells, the relationship between UV dosage and forward mutation frequency was studies. It was observed that UV induced two types of mutation, fractional and whole-colony, at the ad locus. The ratio of the whole-colony to the fractional-colony increased with UV dose. By theoretical treatment, it was deduced that the fractionalcolony mutation was induced by a single-hit and the whole-colony mutation by two single-hit events in sequence, this sequence seeming to have a high probability to occur. These results support the conclusion that the genetic multiplicity of the gene is two, probably corresponding to the individual strands of double-stranded DNA.View full abstractDownload PDF (264K) -
Bungo WADA1963 Volume 4 Issue 2-4 Pages 91-96
Published: 1963
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSThe number of dicentric chromosome bridges induced by betaray irradiations from a source of 90Sr plate and that found in control material were counted by means of in vivo observations in Tradescantia staminal hair cells and it was confirmed that the number of bridges increased with increasing doses.
In comparison of chromosome bridges found in the control material of this experiment with those recorded before the last World War, it was pointed out that effects of radioactive fallout have been preserved as chromosome bridges in the staminal hair cells of Tradescantia at present.View full abstractDownload PDF (270K) -
Hikoyuki YAMAGUCHI1963 Volume 4 Issue 2-4 Pages 97-104
Published: 1963
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSIn mutation breeding, mutation frequencies are expressed as the proportion of X1 ears which segregate mutant progeny. Since mutations occur as sectors in X1 ear and the size of mutated sectors varies with increasing dose, the procedure used every ear for calculation of the mutation frequency might result in underestimates of mutation frequency.
Using the method of the segregation frequency of mutants in mutated X1-ear-branch progenies, it could be shown that the primary branch was traced back to a single cell of rice seed embryo. Mutation frequencies were measured on the X1 ear, X2 plant or X1 ear-branch basis. The deviation from the linear relationship between dose and the frequency of mutations seemed to be less on the X1 ear-branch basis. Consequently, it was proposed to measure the mutation frequency per original treated cell as the proportion of primary branches of X1 ear which segregated mutant progeny.
Furthermore, the mutation frequencies and the segregation ratios were less in the lower primary branches of X1 ear. It was supposed that even in haplontic selection the course of the elimination process was dependent on the environment in which the X2 seeds were produced.View full abstractDownload PDF (333K) -
Toshio SHIOMI, Eiichi INAGAKI, Hiroko INAGAKI, Yoshio NAKAO1963 Volume 4 Issue 2-4 Pages 105-110
Published: 1963
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSThe problem of genetic effects from low dose level radiation is a very important one. We have tested the linear relationship between dose and mutation rates of Drosophila at doses as low as 8 r. The material used was the wild Canton-S strain which were isogenized every four months. Wild males were stocked for one week after their emergence, and irradiated with X-rays. Sex-linked recessive lethals were detected by M-5 method, and about 530, 000 X-chromosomes including the control were examined. The straignt line obtained at the high dose level was in good accord with that obtained by Spencer and Stern (1948). And the curve obtained at high dose level was found to be applicable at the low dose level as well. Among the 26, 897 males treated, there were 25 cases which produced two to fifteen lethals. How to treat the simultaneous occurence of two or more lethals in a set of twenty tested chromosomes originated from one treated male is an important and troublesome problem. However, sufficient evidence is available to conclude that the linear relationship between mutation rates and radiation dose can be applied to low doses down to 8r, by using the sex-linked recessive lethal mutaions in Drosophila, one of the most reliable indicators of mutation induction.View full abstractDownload PDF (244K) -
Yoriaki MATSUDAIRA1963 Volume 4 Issue 2-4 Pages 111-119
Published: 1963
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSThis investigation was carried out to clarify whether or not the induced detrimental genesor gene blocks interact with each other, by means of using Drosophila as the material.
It was ascertained that an interaction between genes or gene bloc ks for the viability in the 2nd and the 3rd chromosome exists. It was also demonstrated that the spectra of viability, that is, the distribution of frequencies in viability, formed bimodal curves for irradiated 2nd chromosomes, for irradiated 3rd chromosomes, and for both irradiated 2nd and 3rd chromosomes. The spectrum of viability in the isogenic lines is discussed with inference to these results.
Further, the genetic load of an organism having two interacting loci is calculated, based on the theoretical model and based on the obtained results.View full abstractDownload PDF (345K) -
Tadashi TSUJII1963 Volume 4 Issue 2-4 Pages 120-125
Published: 1963
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSPearls produced either in pearl oyster or in fresh-water mussel change their colors into black by the irradiation with either γ-ray or neutron rays. In this coloration, blackish pigment are found chiefly in the inserted nuclei of the pearls produced in fresh-water and of marine mollusks and also in the pearl layer of pearls produced in fresh-water mussel, but scarcely be found in those of the pearl layer of the pearls produced in Japanese pearl oyster. The insertion nucleus is made of pearl layer in shell of fresh-water clam.
Both the pearl layer in shell or in pearl of fresh-water clam easily change its color from original to black by the irradiation. In order to clarify the mechanism of the coloration, the colored pearls were observed using the chemical and physical methods.
In physical observation, in the colored pearls examined submicroscopically using electron microscope and x-ray diffractometer and heateffects, no physical differences can be found before and after the irradiation (Figure 1, 2, and Table II).
In chemical observation, the shell of fresh-water clams contain comparatively larger amounts of Mn than those of marine ones (Table III).
Those results shown in Table III suggest that the greater part of Mn in the shell of fresh-water clam really exists and its oxides caused by the irradiation are possibly due to the blackish color.View full abstractDownload PDF (268K) -
Akira TSUYA, Toshihiko TANAKA, Takesaburo MORI, Tadashi HASHIZUME, Yos ...1963 Volume 4 Issue 2-4 Pages 126-145
Published: 1963
Released on J-STAGE: August 29, 2006
JOURNAL FREE ACCESSFour autopsy cases of thorotrast injury were presented, in which one case of liver cirrhosis and three cases of malignant tumors were included. The malignant tumors were diagnosed as cholangiocarcinoma, hemangioendothelioma and osteosarcoma, respectively.
The dose delivered to critical organs, liver and the spleen, were measured spectrometrically and calculated using the method developed by Rundo, on the autopsy specimens.
Several correction factors were introduced to obtain the final estimation of the dose. They are related to the equilibrium state of the thorotrast samples used, biological half life of 228Ra, distribution of thorotrast granules in the tissue and reduction of the critical organ weight, etc..
Average tissue doses delivered were estimated as 0.58 to 2.6 rad per week for the liver and 0.92 to 5.6 rad for the spleen.
Possible relationship between corrected tissue dose and pathological findings was discussed.View full abstractDownload PDF (1112K)
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