Tatsuro Ikeuchi

Chromosome studies in early embryogenesis

Abstract Chromosome studies were made on 520 induced abortuses randomly collected in Sapporo. The mean gestational age was 9.6 ± 2.0 weeks after the first day of the last menstrual period, and the mean maternal age was 26.6 ± 5.8 years. There were 2 cases of X monosomy and 3 cases of autosomal trisomies for C, D, and E chromosomes, respectively. In addition, 12 males with an unusually long Y chromosome, 6 cases with an enlarged short arm or satellite in one of acrocentrics, and 1 each case with a heteromorphic pair of either No. 1 or 16 were found. A high incidence (10 to 42 per cent) of chromosome breakage was noted in 9 cases. Tetraploid cells were frequently observed in 6 cases (5.5 to 16.3 per cent). The sex ratio was 95.4 (XX + X : XY = 266 : 254), showing a slight excess of females over males, though a tendency was shown that the younger the embryonic age the lower the sex ratio.

A male infant with monosomy 21

SummaryA male infant with total monosomy 21 identified by Q-, G- and R-banding is described. His main symptoms are hypertonia, micrognathia, microphthalmus, imperforate anus, ambiguous external genitalia, floating and malopposed thumbs, overlying fingers, right clubfoot and growth retardation. Both parents are phenotypically as well as karyotypically normal.

Differential inducibility of chromosome aberrations and sister-chromatid exchanges by indirect mutagens in various mammalian cell lines

A total of 17 cultured mammalian cell lines of various types was investigated for the inducibility of chromosome aberrations (CAs) and sister-chromatid exchanges (SCEs) after exposure to 3 direct mutagens, cyclophosphamide (CP), dimethylnitrosamine (DMN) and benzo[a]pyrene (BP), without extrinsic metabolizing factors. The following cell lines were highly sensitive to CP as estimated by the dose-dependent increase of either CAs or SCEs, or both: 4 rat ascites hepatomas (AH66-B, AH66-C, AH70B, AH109A), 3 rat esophageal tumors (R1, R2, R3), the Yoshida sarcoma (YS), a Chinese hamster embryonic cell line (B-13), and a human embryonic (HE2236) cell line. 1 golden-hamster embryonic (GHE), 1 human embryonic (HE2144) and 1 human esophageal tumor (TH) cell line were moderately sensitive to CP in terms of the yield of SCEs, though they showed rather low sensitivity when measured by the frequency of CAs. 2 Chinese hamster (CHO-K1, CHL) and 1 human lymphoma (P3HR-1) cell lines were much less sensitive or almost insensitive with respect to the yield of both CAs and SCEs. Considering the above results and taking some other experimental conditions into account, 7 cell lines, including another Chinese hamster cell line (Don 6), were similarly investigated with DMN and BP. The results indicated that AH66-B, which was highly sensitive to CP, was also sensitive to DMN and BP, and that the CP-sensitive R1 and R3 were responsive to DMN. While YS, B-13, Don 6 and P3HR-1 did not show any significant response to DMN, a considerable increment of SCEs was noted in B-13 after treatment with BP, GHE was also notable for its high sensitivity to BP, showing an apparently dose-dependent increase of both CAs and SCEs. HE2144 exhibited a slightly increased rate of SCEs after exposure to BP.

Unbalanced 13q/21q translocation: A revised study of the case previously reported as 21-monosomy

SummaryReexamination was made on a male infant previously reported as 21-monosomy. Extensive chromosome banding analyses in the patient and parents disclosed an unbalanced de novo translocation between chromosomes 13 and 21. The patients karyotype was interpreted as 45,XY,-13,-21,+der(13),t(13;21) (q2 or 3;q1 or 2)pat. The patient showed many clinical features characteristic of 13q- syndrome.

Chromosome banding patterns in an infant with 13q-syndrome

SummaryA case was described of a malformed male infant with partial monosomy for the long arm of chromosome 13. The chromosome banding and autoradiographic analyses revealed a 46,XY,del(13)(q22) karyotype as the most likely interpretation. Both parents were phenotypically as well as karyotypically normal. Tracing the fluorescent marker bands the deleted chromosome of the proband was shown to be of maternal origin.ZusammenfassungEs wird ein männlicher Säugling mit Mißbildungen beschrieben, bei dem sich eine partielle Monosomie für den langen Arm von Chromosom 13 fand. Die Bandenmuster-und Autoradiographie-Untersuchungen zeigten, daß offenbar ein Karyotyp 46,XY, del(13)(q22) vorliegt. Beide Eltern hatten einen normalen Karyotyp und Phänotyp; auf Grund der Fluorescenzbanden konnte das deletierte Chromosom als von der Mutter stammend identifiziert werden.

A chromosome survey of induced abortuses in a Japanese population.

Chromosomal studies were carried out on either cultured or noncultured embryonic tissues derived from 140 cases of induced abortuses which were randomly collected in Sapporo during a period from January, 1963 to April, 1966. The mean maternal age for this series was 27.5±5.8 (S.D.) years, and the mean gestational age was 9.6±3.1 (S.D.) weeks. Among the cases, 133 were found to have a normal chromosome constitution of either male (46-XY) or female (46-XX), with a sex-ratio of 83♀∶50♂. Seven cases were chromosomally abnormal: They were 3 mosaic cases with 45-XO/46-XY, 46-XY/47-XXY and 45-XO/46-XX karyotypes, 1 case of X-monosomy with the 45-XO karyotype, 1 case of X-trisomy with the 47-XXX karyotype, a male with an unusually long Y chromosome, and a female showing a high incidence of chromosome breakage. A high incidence of chromosome abnormalities was obtained in association, within a limited period, of epidemics for three viral diseases.

An Abortus with a Normal/Trisomy 16 Mosaicism: Instability of Trisomic Cells in vitro

SummaryA 46,XX/47,XX,+16 mosaicism was demonstrated in cultured chorionic cells obtained from an abortion material. By tracing polymorphic fluorescent chromosome markers in the abortus and the parents, the karyotypically normal component was confirmed to be non-maternal in origin. The trisomic cells showed a growth disadvantage, and were overtaken by the normal cells in prolonged cultivation.

A preliminary note on the hormonal induction of NADP-linked dehydrogenases in phytohaemagglutinin-stimulated human lymphocytes

SynopsisHuman leucocytes were culturedin vitro with either phytohaemagglutin or 17 β-oestradiol or both, and the enzyme activities of nicotinamide adenine dinucleotide phosphate-linked glucose-6-phosphate dehydrogenase and isocitrate dehydrogenase were assayed. As a result, it was found that these enzymes were considerably induced by oestradiol in phytohaemagglutinin-stimulated lymphocytes, but not in non-stimulated cells. Electrophoretic studies on glucose-6-phosphate dehydrogenase showed that six molecular forms are demonstrable in normal and phytohaemagglutinin-stimulated leucocytes, and that one of the forms was specifically induced by oestradiol in the presence of phytohaemagglutinin.