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J M Scheres

Publications and source records attributed to J M Scheres.

At least 37 records · Page 2Linked to original sources
PubMed1986

Specific translocation t(1;3) in acute myelomonocytic leukemia: a further case.

We describe herein a translocation, t(1;3)(p36;q21), that was found in the bone marrow of a patient with acute myelomonocytic leukemia preceded by a long lasting myelodysplastic phase. An identical translocation has been reported in three other myelodysplastic patients. one of whom also developed an acute myelomonocytic leukemia. The possible significance of this specific translocation is briefly discussed.

Bone Marrow↗
PubMed1986

Heterochromatin in the chromosomes of the gorilla: characterization with distamycin A/DAPI, D287/170, chromomycin A3, quinacrine, and 5-azacytidine.

The chromosomes of the gorilla were extensively studied with various staining techniques labeling the different classes of heterochromatin. The chromosomal distribution of distamycin A/DAPI-, D287/170-, quinacrine-, and chromomycin A3-positive heterochromatic regions, as well as the nucleolus organizer regions, is described and compared with the karyotypes of other hominoid species. Lymphocyte cultures were treated with low doses of 5-azacytidine during the last hours of culture. This cytidine analog induces distinct undercondensation in 37 heterochromatic regions in the 24 gorilla chromosomes. The 5-azacytidine-induced undercondensations are localized not only in most of the distamycin A/DAPI-bright heterochromatic regions but also in many telomeric C-bands of the chromosomes. Furthermore, 5-azacytidine preserves the somatic pairing between heterochromatic regions from the interphase nuclei into the metaphase stage. The homeologies and differences in the chromosomal localization of the various classes of heterochromatin, 5-azacytidine-sensitive regions, 5-methylcytosine-rich DNA sequences, and satellite DNAs in the gorilla, chimpanzee, orangutan, and man are discussed.

5-Methylcytosine↗
PubMed1986

[Down's syndrome in the Netherlands].

In 348 patients with Down syndrome (DS) born in the Netherlands in 1981 and 1982 chromosome studies had been performed before December 1st 1984. Prenatal chromosome studies had revealed 22 cases who could have been born in 1981 and 1982 taking into account a pregnancy duration of 40 weeks. DS rates are determined for five-yearly maternal age classes. These frequencies are compared with those from a reference group, consisting of a compilation of five epidemiological studies which are comparable in their way of presentation of the results and in the ascertainment of the DS cases. The most conspicuous finding in this comparison is that the frequency of DS among children of older mothers (greater than or equal to 40 years) in our study is relatively low. Therefore we presume that a number of patients born in the years 1981 and 1982, particularly from the maternal age groups 40-44 and greater than or equal to 45, are not (yet) referred for cytogenetic characterization. The great majority (+/- 90%) of the postnatally studied cases was presented within the first two months of life. In nearly 95% a standard trisomy 21 was detected and in about 5% a translocation or mosaicism.

Adult↗
PubMed1985

Evolutionary conservation of fragile sites induced by 5-azacytidine and 5-azadeoxycytidine in man, gorilla, and chimpanzee.

Lymphocyte cultures from man, gorilla, and chimpanzee were treated with 5-azacytidine and 5-azadeoxycytidine. These cytidine analogues induce common fragile sites in the chromosome bands 1q42 and 19q13 of man. A rare fragile site is induced by 5-azadeoxycytidine in the band 1q24. The optimum conditions required for inducing these new fragile sites were determined by a series of experiments. The common fragile site in human chromosome 1q42 also exists in the gorilla and chimpanzee in the homologous band 1p32. The fragile site in human chromosome 19q13 was demonstrated in the gorilla in the homologous chromosome band 20q13. These are the first examples found of evolutionary highly conserved fragile sites in homologous chromosome bands in related primate species. The interaction between 5-azacytidine, 5-azadeoxycytidine, and chromosomal DNA; the evolutionary conservation of genes located within or closely adjacent to the fragile sites in the chromosome 1 of Hominoidea; and the phylogenetic origin of the two new common fragile sites are discussed.

Animals↗
PubMed1985

Translocation 1;7 in hematologic disorders: a brief review of 22 cases.

A translocation t(1;7)(p11;p11), previously reported in patients with myelodysplasia or leukemia has been found in seven new cases. The present report briefly reviews the cytogenetic and clinical features of 22 patients with this translocation. The majority of these patients had a history of occupational or therapeutic exposure to toxic substances or radiation. Trisomy 8 or 21 were the most common additional abnormalities, especially in leukemic patients. The t(1;7) should be added to the group of specific cytogenetic abnormalities observed frequently in secondary myelodysplasia and leukemia.

Adolescent↗
PubMed1985

Heritable fragility at 11q13 and 12q13.

The chromosomes of two mentally retarded probands were investigated because they were suspected of having the fragile X syndrome. However two other fragilities were detected. In one patient a fra(11)(q13) was found and in the other a fra(12)(q13). Family studies revealed that both fragile sites were real heritable ones. Besides these two heritable fragile sites, the common fragile site at 3p14 was frequently observed. The effects of BUdR, FUdR and methotrexate on the frequency of the three fragilities were studied. The two heritable fragile sites differed from the common fragile site at 3p14 with respect to their inducibility by FUdR and methotrexate.

Adolescent↗
PubMed1984

Translocation 1;7 in dyshematopoiesis: possibly induced with a nonrandom geographic distribution.

Eight patients with various hematologic disorders had an identical chromosomal aberration in their bone marrow or unstimulated peripheral blood, a translocation t(1;7) interpreted as t(1;7)(p11;p11). The translocation chromosome replaced one normal chromosome #7; therefore, the karyotype of the abnormal cells was trisomic for 1q and monosomic for 7q. Including four cases from the literature, a total of 12 patients (4 women, 8 men) with this translocation are known at the moment. The translocation does not seem to be associated with a specific disorder, but almost all patients had a preleukemic syndrome during some stage of their disease. It is very remarkable that 11 of the 12 patients lived in the Netherlands, and 7 patients had a history of iatrogenic exposure to alkylating agents or irradiation; one patient was a radiation worker and another one had a history of toxic exposure to chloramphenicol. It is suggested, therefore, that the t(1;7) is a possibly induced chromosomal aberration with a clearly nonrandom geographic distribution.

Adult↗
PubMed1984

[Immunologic and cytogenetic aspects of ataxia telangiectasia].

Immunological and cytogenetic studies were performed in 6 patients with ataxia telangiectasia (AT). Immunological disturbances were found in these patients: immunoglobulin deficiencies (IgA, IgE, IgG2 and IgG4), decreased cellular immunity and a defect in the synthesis of specific antibodies. Cytogenetic studies revealed chromosome 7 and/or 14 abnormalities in all patients. X-irradiation of AT cells induced an excessive increase in chromosome and chromatid breaks. The DNA synthesis inhibition after X rays was less in AT patients compared to controls. The possibilities of early diagnosis and the eventual relationship between immunological and cytogenetic findings are discussed.

Adolescent↗
PubMed1983

Malignant histiocytosis. Clinical and cytogenetic studies in a newborn and a child.

Malignant histiocytosis (MH) was diagnosed on the cytologic and cytochemical features of the malignant cells present in bone marrow smears from an infant and a child. The diagnosis of MH was confirmed by light and electron microscopic studies on bone marrow and skin biopsy specimens, and bone marrow and liver biopsy specimens, respectively. Both patients showed a deterioration while receiving prednisone monotherapy, but they responded well to a combination of vincristine and cyclophosphamide. The infant has remained disease-free for 52+ months now, but the child died of a relapse 11 months after diagnosis. Cytogenetic studies of blood and/or bone marrow cells were performed before treatment. In the infant, a pathologic cell line with a translocation t(8;16)(p11;p13) was found; this abnormality was no longer present after remission was obtained. In the second patient, a hyperdiploid cell line with major karyotypic anomalies was found. When studied in relapse and shortly before death, additional chromosomal abnormalities were seen. The data from this study show that prednisone should be used with caution in MH, and that it should be omitted from combination chemotherapy when adverse effects are noted during short-term monotherapy. Also, cytogenetic studies should be performed more often in MH to determine the significance and possible nonrandomness of chromosomal abnormalities in this disease.

Antineoplastic Agents↗
PubMed1983

Hypersensitivity to ionizing radiation, in vitro, in a new chromosomal breakage disorder, the Nijmegen Breakage Syndrome.

The Nijmegen Breakage Syndrome (NBS) is a new chromosomal instability disorder different from ataxia telangiectasia (AT) and other chromosome-breakage syndromes. Cells from an NBS patient appeared hypersensitive to X-irradiation. X-rays induced significantly more chromosomal damage in NBS lymphocytes and fibroblasts than in normal cells. The difference was most pronounced after irradiation in G2. Further, NBS fibroblasts were more readily killed by X-rays than normal fibroblasts. In addition, the DNA synthesis in NBS cells was more resistant to X-rays and bleomycin than that in normal cells. The reaction of NBS cells to X-rays and bleomycin was similar to that of cells from patients with ataxia telangiectasia. Our results indicate that NBS and AT, which also have similar chromosomal characteristics, must be closely related.

Adolescent↗
PubMed1982

Prometaphase banding of human chromosomes with basic fuchsin.

A technique is described for the production of detailed and richly contrasting G-band patterns in human prometaphase chromosomes with the aid of the triphenylmethane dye basic fuchsin. The usefulness of this method is illustrated by its application for the precise analysis of two chromosome 11 rearrangements. It is also demonstrated that high-resolution banding with basic fuchsin can reveal bands not present in the international standard idiogram of human prophase chromosomes (ISCN 1981). The technique described can also be used for easy recognition of the late replicating X chromosome, which stains darker than its early replicating homologue. A preliminary analysis of the late replicating X chromosomes in a 49,XXXXY individual suggests that the three supernumerary X chromosomes do not necessarily replicate synchronously.

Chromosome Banding↗
PubMed1981

Sister-chromatid exchanges induced in vitro by cyclophosphamide without exogenous metabolic activation in lymphocytes from three mammalian species.

The induction of sister-chromatid exchanges (SCEs) by cyclophosphamide (CP) in human, rat and rabbit lymphocytes was studied in vitro without exogenous metabolic activation. In contrast with published reports, CP induced SCEs in lymphocytes from all three species, indicating that cultured lymphocytes possess the metabolic capacity to convert this indirect-acting mutagen.

Animals↗
PubMed1981

A new chromosomal instability disorder: the Nijmegen breakage syndrome.

A 10-year-old boy with microcephaly, stunted growth, mental retardation, café-au-lait spots and immunodeficiency is described. An older brother of the patient had the same clinical symptoms and a more severe immunodeficiency. Cytogenetic studies in the proband revealed a typical form of chromosome instability with multiple rearrangements of chromosomes 7 and 14. Such abnormalities were also present, though in very low frequencies, in the father and three of the phenotypically normal sibs. The similarity of the symptoms in the two sibs, the close consanguinity of their parents and the results of the cytogenetic studies in the family favour the hypothesis that the disorder is an inherited one. The clinical features and the chromosome aberrations as present in the proband are usually found in chromosomal breakage syndromes, but it was possible to exclude each of the classical chromosomal breakage syndromes on clinical and/or cytogenetic grounds.

Adolescent↗