Akira Tonomura

Some properties of purified phytohemagglutinin from Lens culinaris seeds

Abstract Lens culinaris phytohemagglutinin was purified by specific adsorption on Sephadex G-100 and subsequent displacement with d -glucose. The homogeneity of the purified hemagglutinin was ascertained by ultracentrifugal analysis and polyacrylamide gel electrophoresis. The purified hemagglutinin had a s020,w value of 3.4 S. This hemagglutinin was disclosed to be a kind of glycoprotein containing 1.5% glucose and 0.5% glucosamine. The specificity of the purified hemagglutinin was tested by hemagglutination-inhibition assays and found to be essentially the same as that of concanavalin A. In each step of the purification, the mitogenic activity against human peripheral lymphocytes was found to be always confined to the fraction which had the hemagglutinating activity. Morphological studies on hemagglutinin-stimulated cultures indicated that at 72 h about 15% of the cell population had been transformed by the purified hemagglutinin.

The biological activity of hydrogen peroxide: I. Induction of chromosome-type aberrations susceptible to inhibition by scavengers of hydroxyl radicals in human embryonic fibroblasts

The cytogenetic effect of hydrogen peroxide (H2O2) was investigated in human embryonic fibroblasts. Chromosome-type aberrations were found together with chromatid-type aberrations in metaphase cells harvested 24 h after a single 10-min treatment with 10(-5)-10(-3) M H2O2 in 0.9% NaCl solution. The chromosome-type aberrations were observed to be predominantly dicentrics and deletions. Both types of aberration showed a dose-response relationship to the dose of H2O2 over the range of 10(-5)-1.5 X 10(-4) M H2O2. The intercellular distribution of dicentrics showed a Poisson distribution. Centric and acentric rings and abnormal monocentrics were a minor fraction of the chromosome-type aberrations. The chromatid-type aberrations observed, such as breaks, exchanges and gaps, showed no dose-response relationship. The frequency of isochromatid breaks was higher than that of chromatid breaks and approximately 70% of the isochromatid breaks were found in the centromeric or pericentromeric region. The intercellular distribution of chromatid exchanges showed an over-dispersed distribution. The generation of aberrations by H2O2 was effectively suppressed by catalase and several scavengers of hydroxyl radicals (.OH) such as ethanol, dimethyl sulfoxide (DMSO) and mannitol. This result suggest that .OH plays an essential role in the generation of the chromosome aberrations by H2O2.

Reexamination of paternal age effect in Down's syndrome

SummaryPaternal age distribution for 1279 cases of Downs syndrome born in 1952–1968 was compared with the corresponding distribution for the general population, corrected for the maternal age as well as for the year of birth of the patients. Although there was no difference in the mean paternal age, the two distributions differed significantly, largely due to the excess of fathers aged 55 years and over and to the deficit of those aged 40–44 years in the patients born to mothers aged 30 years and over. The overall pattern of the relative incidence of Downs syndrome with advancing paternal age, with maternal age controlled, seems consistent with the hypothesis proposed by Stene et al. (1977). It increased from 0.8 for fathers aged 20–24 years slowly up to 1.2 for those aged 45–49 years, though with an intermediate drop to 0.8 at the age of 40–44 years, and then sharply to 2.4 for those aged 55 years and over. This rising pattern of the relative incidence with paternal age was essentially the same for the patients born in 1952–1960 and for those born in 1961–1968, although the slope was less steep in the latter than in the former group.

Chromosome rearrangements at 12q13 in two cases of chondrosarcomas

We analyzed the karyotypes of two moderately differentiated (grade 2) chondrosarcomas. Case 1 had a reciprocal translocation between chromosomes 6 and 12, t(6;12)(q25;q13) in most of the cells analyzed, as well as trisomies of chromosomes 7, 8, 11, 17, 19, and 21 and tetrasomy of chromosome 19. A reciprocal translocation involving chromosomes 12 and 19, t(12;19)(q13;q13), was noted as a highly clonal abnormality in the other case. Some cells had t(12;19) as the sole chromosome abnormality. Thus, chromosome rearrangements involving the long arm of chromosome 12 at the same region (q13) were commonly identified in the two tumors. These findings suggest that the rearrangements at 12q13 are nonrandom acquired changes that characterize a subgroup of chondrosarcomas.

MOLECULAR NATURE OF CHROMOSOME 5Q LOSS IN COLORECTAL TUMORS AND DESMOIDS FROM PATIENTS WITH FAMILIAL ADENOMATOUS POLYPOSIS

SummaryFamilial adenomatous polyposis (FAP), which includes familial polyposis coli (FPC) and the Gardner syndrome (GS), is a genetically determined premalignant disease of the colon inherited by a locus (APC) mapping within 5q15–q22. To elucidate the role of 5q loss in FAP tumorigenesis, we analysed 51 colorectal tumors and seven desmoids from 19 cases of FPC and five GS patients, as well as 15 sporadic colon cancers. RFLP analysis revealed a high incidence of allelic deletion in hereditary colon cancers as well as in sporadic colon cancers with a peak at the APC locus. APC loss resulted primarily from interstitial deletion or mitotic recombination. Combined tumor and pedigree analysis in a GS family revealed loss of normal 5q alleles in three tumors, including a desmoid tumor, which suggests the involvement of hemizygosity or homozygosity of the defective APC gene in colon carcinogenesis and, possibly, in extracolonic neoplasms associated with FAP.

Cytogenetic and ultrastructural studies on ten patients with acute promyelocytic leukemia, including one case with a complex translocation

Chromosomal banding analyses and ultrastructural studies were performed on ten cases of acute promyelocytic leukemia (APL-M3). A reciprocal translocation, t(15q + ;17q-), was found in six of them, and the possible breakpoints of these chromosomes were assigned at bands 15q22 and 17q12. In addition, trisomy 8, trisomy 8 and 21, and an isochromosome of the long arm of the translocated #17, i(17q-), were observed in addition to the 15;17 translocation in three cases, respectively. Furthermore, one patient was found to have a complex translocation in the marrow cells, i.e., 47,XX,+X,t(1p+;5q-;15q+;17q-). Ultrastructural studies demonstrated that the leukemic cells obtained from six of the seven patients with the chromosomal changes involving 17q12 and from two of the three with normal karyotypes contained stellate rough surface endoplasmic reticulum (stellate rER) complexes and/or inclusion bodies in part of the dilated rER.

Chromosome Changes in Desmoid Tumors Developed in Patients with Familial Adenomatous Polyposis

Chromosome analyses were performed on benign desmoid tumors obtained from two female patients with familial adenomatous polyposis (FAP), one of whom was diagnosed as having Gardner syndrome (GS). The modal chromosome number was 46 in both specimens, and detailed Q‐banding analysis in Case 1 (GS) revealed a clonal abnormality of an interstitial deletion of the long arm of chromosome 5, del(5)(q2lq31). The deleted region included an assigned locus for an FAP major gene (5q21‐q22). All of the metaphases analyzed in this case showed an extra segment of bright fluorescence on the short arm of chromosome 15, but this unusual chromosome (15p +) was observed in both peripheral lymphocyte and skin fibroblast cultures from the patient, indicating that the 15p+ was constitutional in nature. In Case 2, no clonal rearrangements were Identified and most cells had a normal karyotype. However, two cells showed rearrangements involving a 17q with non‐identical breakpoints, one of which was observed as a solitary chromosome change. Based on the present findings in Case 1 and those reported so far, the chromosomal defect on 5q might be one of the causal genetic events primarily associated with the development of both benign desmoid tumors and colorectal adenomas and carcinomas in FAP patients.

Chronic myelogenous leukemia with a complex Ph1 translocation in an XYY male

We encountered a 38-year-old Japanese male patient with chronic myelogenous leukemia (CML), whose bone marrow and peripheral blood cells during the chronic and blastic phases contained a complex Ph1 translocation and an extra Y chromosome [i.e., 47,XYY,t(9;22;13)(q34;q11;q14)]. A karyotypic analysis of PHA-stimulated lymphocytes showed the constitutional karyotype to be 47,XYY. Thus, it was considered that CML with a complex Ph1 translocation developed in an XYY male; such a case has not been reported, so far. A B-lymphocyte cell line with the complex Ph1 translocation was established by the procedure of Epstein-Barr virus transformation. The presence of the complex Ph1 translocation in the B-lymphocyte cell line suggests that some of the B lymphocytes in this patient originated from the CML clone.

Chronic myelogenous leukemia with translocations (3q-;9q+) and (17q-;22q+). Possible crucial cytogenetic events in the genesis of CML.

SummaryTwo reciprocal translocations involving chromosomes 3, 9, 17, and 22 were found in a patient with seemingly Ph1-negative chronic myelogenous leukemia (CML). The two translocations were t(3;9)(q21;q34) and t(17;22)(q21;q11); the breakage in chromosomes 9 and 22 apparently occurred at the same point as in the usual Ph1 translocation, t(9;22)(q34;q11).From the present evidence and a review of the literature it appears that the breakage on both chromosomes 9 and 22 at the special regions and the separation of the fragments are present in practically all standard and variant Ph1 translocations, even those in which the terminal region of the long arm of chromosome 9 (9q) does not seem to be involved in the rearrangement; however, a translocation between chromosomes 9 and 22 is not an obligatory result of the rearrangement, as seen in the present case. Thus, we postulate that the breakage on both chromosomes 9 and 22 at the special regions and separation of the fragments are the crucial cytogenetic events in the genesis of CML and stress the importance of paying careful attention to the terminal region of 9q, particularly when chromosome 9 does not seem to be involved in the rearrangement.

Rearrangements of Chromosome 3 in Nonfamilial Renal Cell Carcinomas from Japanese Patients

Cytogenetic studies were successfully carried out in 5 tumor tissues from Japanese patients with nonfamilial renal cell carcinoma, histologically diagnosed as clear cell subtype. Mitotic cells were obtained by a combined method of enzymatic disaggregation and short‐term culture (6–12 days). The modal chromosome numbers were found to be diploid or near‐diploid in all the cases examined. Every case showed characteristic structural and numerical abnormalities. Rearrangements in the short arm of chromosome 3 were observed as clonal abnormalities in all the cases, including a translocation t(3;6) resulting in a partial loss of 3p (3 cases), a terminal deletion of 3p (one case) and 2 different translocations involving 3p and 8p (one case). The other clonal abnormalities were a whole or partial trisomy of chromosome 7 and a loss of Y chromosome. The overall results in the present study were consistent with those of our previous data in American patients, and suggest that the rearrangements of chromosome 3 leading to a partial loss of its short arm may play primary and significant role(s) in the development of renal cell carcinoma.