Yukimasa Shiraishi

Chromosome aberrations induced by monomeric acrylamide in bone marrow and germ cells of mice

Acrylamide induces chromatid exchanges and breaks with considerable frequency in spermatogonia of mice with long-term administration (3 weeks), though not, remarkably, with short-term administration (1--2 weeks. At 12 and 24 h after single injections with 50, 100 and 150 mg/kg acrylamide, evaluation of the cytogenetic effect is difficult in the spermatogonia because of an extreme reduction of mitotic cells. Aneuploid and polyploid cells increase with time after treatment in both marrow and spermatogonial cells, while the aberration frequency shows no increase in marrow after both oral-administration and injection. Evidently the spermatogonia are thus rather more sensitive to acrylamide than marrow cells. On the other hand, the SCE frequency is at the control level in treated subjects in marrow and spermatogonia. Acrylamide induces chain quadrivalents, ring quadrivalents, fragments and univalents which are particularly evident in primary spermatocytes in both oral administration and injection, though it is questionable whether these structural changes deal with spermatogonia, or otherwise with the S-phase primary spermatocytes. There is a possibility that the aberrant cells thus produced can develop into spermatozoa carrying a certain type of reciprocal translocation which leads to semi-sterile progeny. In relation to the above problem detailed investigations into this type of rearrangement in primary spermatocytes are needed.

Banding pattern analysis of human chromosomes by use of a urea treatment technique

A new technique to reveal the banding pattern of human chromosomes is described. Slides prepared by the routine air drying technique were treated with urea-Sörensen buffer solution for ten minutes at pH 6.8 at 37° C. Individual pairs of all human chromosomes exhibited a characteristic banding pattern by this technique, and by its use the karyotypes were analysed. With the exception of some minor differences the banding patterns obtained by the present technique appeared to be identical with those obtained by the Giemsa staining and quinacrine fluorescence methods carried out by previous workers.

A summary of cytogenetic studies on 534 cases of chronic myelocytic leukemia in Japan

Cytogenetic and clinical data on 534 patients with chronic myelocytic leukemia (CML) were collected from 10 institutions in Japan. The results of the analysis of the data were in substantial accord with those of the First International Workshop on Chromosomes in Leukemia and other published data, but certain differences were noted in the frequency of Philadelphia chromosome (Ph1)-negative cases, unusual and complex Ph1 translocations, and additional chromosome changes. Some of the findings are discussed with respect to the origin of unusual and complex Ph1 translocations, the relationship between chromosome abnormalities and survival, and geographic differences in chromosome abnormalities.

Cytogenetic studies in 12 patients with itai-itai disease.

SummaryAmong 12 Itai-Itai disease patients examined, 8 patients showed a remarkably high frequency of chromatid aberrations, whereas the other 4 patients showed a much lower frequency of such aberrations, although a significant number of stable type aberrations was observed also in the latter patients. The frequencies of aneuploid cells of all 12 patients were significantly higher than those of the controls. The abnormalities were found in 50-hour and 72-hour cultures, from which it can be concluded that the aberrations occurred in the blood stem cell of the patients. In addition to these structural and numerical aberrations, satellite associations of the D and G group chromosomes were often observed.

Analysis of single and twin sister chromatid exchanges in endoreduplicated normal and bloom syndrome B-lymphoid cells

Single and twin sister chromatid exchanges (SCEs) were analysed in the colcemid-induced endoreduplicated normal and Bloom syndrome (BS) B-lymphoid cells with diplochromosomes. In normal cells, an equal number of SCEs occur in each of the two cell cycles; the ratio of single (= 5.51 SCEs/cell) to twins (= 2.64 SCEs/cell) was 2∶1 on the endoreduplicated-cell basis, and it was 1∶1 on the diploid-cell basis. In contrast, in 29 endomitoses from one BS B-lymphoid line, a manyfold increase of single SCEs was detected and 139.4 single SCEs on the average were counted, whereas twin SCEs were rare and only 4.9 twin SCEs were countable. In BS cells, the ratio of single (= 139.4 SCEs/cell) to twins (4.9 SCEs/cell) was 28∶1 on the endoreduplicated-cell basis, and it was 14∶1 on the diploid cell-basis; the rates of S1 and S2 exchanges were 4.9 and 69.7 SCEs/cell, respectively. The present study strongly indicates that most of BS SCEs occur during the second cell cycle when BrdU-containing DNA is used as template for replication and that BrdU enhances BS SCEs.

Diagnostic and prognostic significance of chromosome abnormalities in marrow and mitogen response of lymphocytes of acute nonlymphocytic leukemia

Chromosomes of bone marrow from 28 patients with acute nonlymphocytic leukemia (ANLL) (26 with AML, 2 with AMMoL), 19 of whom had chromosome abnormalities, were studied; 11 cases exhibited previously unreported karyotypic abnormalities. The marrows of two cases had 8-21 translocations associated with an iso-X chromosome in the female patient and with 9q13- and a missing Y in the male patient. Usually, AML patients with a 8-21 translocation have been considered to have a good prognosis; however, our cases had rather short survival times. Therefore, the prognosis of AML with an 8-21 translocation but associated with other abnormalities is still not clear. Centromere spreading (CS), which was originally reported in marrow cells of megaloblastic anemia (B12 and folic acid deficiency), was detected in leukemic cells, disappeared during remission, and reappeared on relapse. These findings suggest that CS may be a new type of abnormality in AML. In two patients with atypical hypoplastic anemia and hemolytic anemia, chromosome abnormalities were detected at the anemic stage. One case with CS was associated with atypical hypoplastic anemia and developed AML after 1 year; the other with 48,XY,+i(1q),+3,/12 and -14 had hemolytic anemia and developed AMMoL 3 weeks later. Interestingly, identical clones were detected both before and after the clinical diagnosis of leukemia. These cases strongly support the concept that some chromosome abnormalities precede the clinical manifestations of leukemia. The present study also revealed that lymphocytes in ANLL respond poorly to PHA in the presence of high numbers of blasts but do respond well to mitogens during remission. Therefore, the response of lymphocytes to PHA may serve as one criterion for determining remission.

Effects of mitomycin C on sister chromatid exchange in normal and Bloom's syndrome cells.

Blooms syndrome lymphocytes, which are characterized by a high incidence of sister chromatid exchanges (SCE: 80.6 per cell), were treated with mitomycin C (MMC) and the effect of the chemical on SCE frequency compared with that in normal cells. Raising the concentration of MMC from 1 X 10(-9) to 1 X 10(-7) g/ml led to about 10-fold increase (61.7 SCE per cell) in the SCE frequency over the base line in normal lymphocytes (6.4 SCE per cell), though chromosome aberrations remained at a relatively low frequency. MMC caused about a two-fold rise in SCE in cells of Blooms syndrome (128.8 SCE at 10(-9) g/ml; 139.3 SCE at 10(-8) g/ml). The frequency of chromosome aberrations in Blooms syndrome cells at concentrations of MMC of 1 X 10(-9) and 1 X 10(-8) g/ml was 0.350 and 0.825 per cell, respectively, and low when compared to the increased number of SCE. The increased frequency of SCE in normal and Blooms syndrome cells is in contrast to the reported findings with cells from Fanconis anemia and xeroderma pigmentosum. The distribution of SCE in MMC-treated normal cell correlates with that of spontaneous SCE in cells of Blooms syndrome.

A summary of cytogenetic, morphologic, and clinical data on t(8q−;21q+) and t(15q+;17q−) translocation leukemias in Japan

Cytogenetic, morphologic, and clinical data of 33 acute nonlymphocytic leukemia (ANLL) patients with t(8q - ;21q+) and 19 patients with acute promyelocytic leukemia (APL) were collected from seven laboratories in Japan. The latter class included 18 patients with t(15q + ;17q-) and one with a normal karyotype. The t(8q - ;21q+) and t(15q + ;17q-) translocations were each shown to be associated with a specific type of ANLL, namely, AML-M2 and APL-M3, respectively. No patient with APL had the M3 variant. The t(8q - ;21q+) translocation seems to be more common as an abnormality in ANLL in Japan as compared to findings in other countries. The high incidence of t(15q + ;17q-) among Japanese patients with APL indicated in this study, however, still awaits confirmation.

Differential Response of Sister Chromatid Exchange and Chromosome Aberrations to Mitomycin C of Normal and Abnormal Human Lymphocytic Cell Lines

Mitomycin C (MMC) induced chromosome aberrations and an increased sister chromatid exchange (SCE) incidence in a cell line derived from normal lymphocytes, whereas in lines originating from cells of chronic lymphocytic leukemia (lines SN1029 and SN1033) and Burkitt lymphoma (lines B35 M and HR1K) MMC caused a striking increase in SCE, but not in the frequency of chromosome abnormalities. The latter may be due to the failure of the cells with chromosome aberrations to survive, possibly related to their high sensitivity to MMC. The increased rate of SCE with MMC treatment was more marked in the neoplastic lymphocytic cells than in the normal ones; the sensitivity of SN1029 and SN1033 cells was 10 times higher and that of B35M and HR1K cells about 5 times higher than that of the normal cells. These observations suggest that the MMC-induced high rate of SCE in the neoplastic cells may in some aspects differ from the mechanism(s) leading to chromosome aberrations; and that SCE is a much more sensitive indicator of MMC effects than chromosome aberrations.

Establishment of B-lymphoid cell lines retaining cytogenetic characteristics of Bloom syndrome

The present study describes the establishment of and chromosomal changes in B-lymphoid cell lines from cells of Bloom syndrome (BS) patients using Epstein-Barr virus (EBV). Even though PHA-stimulated BS lymphocytes from all five patients studied showed high levels of sister chromatid exchange (SCE), three EBV-transformed BS-B-lymphoid cell lines had normal levels of SCE and two yielded two types of cell populations, i.e., one with increased SCE and chromosome instability (including breaks and quadriradials) and another with normal levels of SCE and without structural aberrations. The karyotypic abnormalities, as observed in the BS lines have not been seen in the cells of any established normal B-lymphoid lines transformed by EBV and strongly suggest that the chromosome abnormalities in the BS--B-cell lines with abnormal karyotypes originated in vivo and not through an in vitro effect of EBV. Furthermore, in the EBV-transformed B-cell lines, we found quadriradial formation between sister chromosomes during endomitoses instead of between homologous chromosomes, strongly suggesting that quadriradial formation may be closely related to SCE. The coexistence in BS subjects of abnormal and normal populations of cells with respect to the number of SCE awaits explanation.