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Biomedical subjects

T Sofuni

Publications and source records attributed to T Sofuni.

At least 163 records · Page 9Linked to original sources
PubMed1984

Kinetics of micronucleus formation in relation to chromosomal aberrations in mouse bone marrow.

A simulation analysis of the kinetics of micronucleus formation in polychromatic erythrocytes in mouse bone marrow was performed after a single administration of 3 chemicals--mitomycin C (MMC), 6-mercaptopurine (6-MP) and 1-beta-D-arabinofuranosylcytosine (Ara-C)--with different modes of action. The time-response patterns in the incidence of chromosomal aberrations and micronuclei after treatment with each chemical were compared and subjected to the simulation study with 3 parameters. Two of them, the time between the final mitotic metaphase of the erythroid series and nucleus expulsion (T1), and the duration of the polychromatic erythrocyte (PCE) stage in the bone marrow (T2), were almost identical for the 3 chemicals. However, the coefficients of formation rate of micronucleated cells resulting from cells with chromosomal aberration(s) (k) differed: Ara-C differed from the other two. These results indicate that chromosomal aberrations, especially chromatid breaks and probably gaps, induced by this chemical, effectively contribute to micronucleus formation. The DNA content of micronuclei was also compared to the length of acentric fragments induced by Ara-C and it was found that their distributions were comparable. These findings strongly suggest that chromosomal aberrations induced by chemicals are essential events for the induction of micronuclei in the PCE of bone marrow.

Animals↗
PubMed1984

Induction of chromosomal aberrations in cultured Chinese hamster cells in a superoxide-generating system.

The induction of chromosomal aberrations in a superoxide-generating system using xanthine oxidase and hypoxanthine was investigated in cultured Chinese hamster cells. The production of chromosomal aberations in this system was inhibited by the addition of cytochrome C. This finding indicates that the generation of superoxide was the primary requirement for induction of chromosomal aberrations. On the other hand, superoxide dismutase showed no effect on the frequency of chromosomal aberrations, whereas catalase was effective in preventing the aberrations. It is conceivable, therefore, that the induction of chromosomal aberrations in the superoxide-generating system may be directly or indirectly due to hydrogen peroxide formed in the cultured medium as a result of the spontaneous dismutation reaction of superoxide.

Animals↗
PubMed1984

Primary mutagenicity screening of food additives currently used in Japan.

Salmonella/microsome tests (Ames tests) and chromosomal aberration tests in vitro using a Chinese hamster fibroblast cell line were carried out on 190 synthetic food additives and 52 food additives derived from natural sources, all of which are currently used in Japan. Fourteen out of 200 tested in the Ames assay showed positive effects and 54 out of 242 were positive in the chromosome test. Three additives (erythorbic acid, chlorine dioxide and beet red) were positive only in the Ames test, although their mutagenic potentials were relatively weak, while 43 additives were positive only in the chromosome test. Eleven additives (calcium hypochlorite, cinnamic aldehyde, L-cysteine monohydrochloride, Food Green No. 3 (Fast Green FCF), hydrogen peroxide, potassium bromate, sodium chlorite, sodium hypochlorite, sodium nitrite, cacao pigment and caramel) were positive in both the Ames test and the chromosome test. The usefulness of such primary screening tests combining two different genetic end-points, gene mutation and chromosomal aberration, and some correlation between mutagenicity and carcinogenicity of food additives are discussed.

Animals↗
PubMed1983

An application of Acridine Orange fluorescent staining to the micronucleus test.

Acridine Orange fluorescent staining was applied to the micronucleus test in mice and rats. Micronuclei emitted bright green fluorescence and were easily distinguished from micronucleus-like inclusions or contaminants. In rat bone-marrow cells, micronuclei with green fluorescence could be easily distinguished from granules accidentally dispersed from broken mast cells, which showed bright red fluorescence. Therefore, it is recommended that the Acridine Orange staining method be used to provide more reliable data in the micronucleus test.

Acridine Orange↗
PubMed1981

Mutagenicity studies on alcohol extracts from gamma-irradiated potatoes.

The alcohol extracts freshly prepared from gamma-irradiated potatoes were examined for their mutagenic activity in bacterial and mammalian cell systems. Negative results were obtained from all following test systems: Mutation assays with Salmonella typhimurium His- strains such as TA 100, TA 98, TA 1535, TA 1537, and streptomycin-dependent mutant (SMd) strain, TA 100-10, inductests with Escherichia coli strains, K 12 GY 5027 and K 12 C600, chromosomal aberration tests with Chinese hamster cells in culture, as well as micronucleus tests in mice. In addition, no difference in the mutagenic activities was found between extracts prepared from the irradiated and the unirradiated potatoes, suggesting that no mutagenic substance was produced in potatoes following gamma-irradiation.

Alcohols↗
PubMed1980

Chromosome heteromorphisms in the Japanese. II. Nucleolus organizer regions of variant chromosomes in D and G groups.

The nucleolus organizer regions (NORs) of variant D- and G-group chromosomes characterized by enlargements of the short arms including secondary constrictions and satellites, were examined using the silver-staining method. Of a total of nine variants examined, four were found to have double Ag-stained NORs in the enlarged short arm, two were found to involve chromosome 22, one was a 13, and one, a 14. Four of the other variants had only one AG-stained NOR. From the positions of the NORs, three of them were judged to have enlarged satellites (two chromosomes 15 and 22) and the other an enlarged short arm (a 15). In the remaining variant (a 14), no Ag-stained material was noted in the short arm, so it could not be determined whether this variant chromosome was derived from the enlargement of the short arm or from satellites. Based on the position of the Ag-stained NORs and staining intensity of the Q and C methods in the short arms, mechanisms of producing the enlarged short arms of D- and G-group chromosomes are discussed.

Asian People↗
PubMed1976

Paracentric inversion of a human chromosome 7.

In the course of chromosome studies of atomic bomb survivors in Hiroshima using the trypsin-G-banding and Q-banding methods, a 40-year-old male was found to have an abnormal banding pattern in the long arm of a chromosome 7, although no such abnormality was detected by ordinary staining method. Since all other chromosomes apparently had normal banding patterns, the abnormality was determined to be a paracentric inversion of a chromosome 7, which is described as 46, XY, inv (7) (q22q31). This is the first demonstration of a possible paracentric inversion in man.

Adult↗
PubMed1975

A new type of inversion of a human Y chromosome.

Using chromosome banding techniques, a phenotypically normal male was found to have an abnormal banding pattern of the Y chromosome. By the constitutive heterochromatin staining method, a darkly stained band was located on the short arm and the proximal region of the long arm. The quinacrine staining method also showed a similar abnormal banding pattern: a brightly fluorescing band was seen on the short arm and the proximal region of the long arm. By the conventional Giemsa staining method, however, no specific morphological abnormality was detected in the aberrant Y. On detailed karyotype analyses no recognizable abnormality of banding patterns of any other chromosome was found aside from the abnormal Y. The abnormality was determined to be a complex inversion of the Y chromosome, which is described as 46,X,inv(Y)(pter leads to p11::q11 leads to q12::cen::q12 leads to qter).

Aged↗
PubMed1975

Autoradiographic and fluorescent staining studies of bone marrow chromosomes from a patient with acute granulocytic leukemia.

Results of cytogenetic studies of a patient with acute granulocytic leukemia are described. The modal number of chromosomes in cells from bone marrow samples was 43; the karyotype was characterized by missing chromosomes in groups B, C, and E. According to successive studies of the same metaphases by fluorescent staining and autoradiographic techniques, the labeling pattern of chromosomes in leukemic cells was generally similar to those observed in normal cultured leukocytes, whereas the fluorescent pattern of leukemic chromosomes was rather indistinct, and the bright fluorescent pattern of the Y chromosome was not apparent.

Acute Disease↗