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M Prieur

Publications and source records attributed to M Prieur.

At least 73 records · Page 4Linked to original sources
PubMed1989

Increase of sister chromatid exchanges in excision repair deficient xeroderma pigmentosum.

The distribution of spontaneous sister chromatid exchanges (SCEs) was studied in PHA-stimulated lymphocytes from 15 patients affected by xeroderma pigmentosum (XP). The study of unscheduled DNA synthesis (UDS) in twelve of these patients showed that seven were deficient and five proficient. The number of SCEs in XP patient cells was higher than in those of 19 controls, and the distributions of SCEs per cell were significantly different. However, the results varied when XP patients were considered in relation to their UDS: the group of XP patients with proficient UDS did not differ, whereas the group of XP patients with deficient UDS was very significantly different from controls. The group not tested for UDS was similar to the deficient UDS group. The possible relationship between the increase of SCEs and the type of DNA repair defect is discussed.

Adolescent↗
PubMed1989

The chemotherapeutic drug melphalan induces breakage of chromosomes regions rearranged in secondary leukemia.

A cytogenetic study is reported on the lesions induced in vitro by melphalan, a currently used anticancer drug. The distribution of 2166 breakpoints shows that they do not occur at random. There is a large excess of breaks in region q1 of chromosome 9 and R bands are significantly more affected than G-band-rich segments. Furthermore, some regions of chromosomes 5, 7, 11, and 17, which are the chromosomes usually rearranged and deleted in secondary leukemias, presumably induced by such treatments, are frequently affected. It is presumed that the frequent involvement of 9q1 largely reflects preexisting monostrand breaks. The frequent breakage of chromosomes 5, 7, 11, and 17 and of R bands in general, which are known to be G-C rich, may result from the preferential methylation of the O6 of guanine by melphalan.

Acute Disease↗
PubMed1989

Unusual karyotypic evolution in subacute myelomonocytic leukemia in two monozygotic twins.

A subacute myelomonocytic leukemia was diagnosed in 28-month-old cotwins. At this age, their spontaneously dividing cells had a normal karyotype. A few months later, after treatment with 6-mercaptopurine, the following karyotypes were observed: 50,XX, +X, +13, +19, +21 in one and 51,XX, +X, +X, +10, +19, +21 in the other. After bone marrow transplantation, both relapsed although they had received high doses of chemo- and radiotherapy. One developed a clone 46,XX,del(20q), which acquired other clonal rearrangements. The other child developed two different abnormal clones, both with unbalanced rearrangement of chromosome 13. Some of these clones may correspond to immature erythroblasts. The gain of chromosomes, especially for #13, which occurred independently in the cotwins by various mechanisms and at different periods during the disease, is very striking. It may indicate the existence of a strong selective advantage for trisomic 13 cells and may be related to the genetic constitution of the patients.

Bone Marrow Transplantation↗
PubMed1989

Critical role of the D21S55 region on chromosome 21 in the pathogenesis of Down syndrome.

The duplication of a specific region of chromosome 21 could be responsible for the main features of Down syndrome. To define and localize this region, we analyzed at the molecular level the DNA of two patients with partial duplication of chromosome 21. These patients belong to two groups of Down syndrome patients characterized by different partial trisomies 21: (i) duplication of the long arm, proximal to 21q22.2, and (ii) duplication of the end of the chromosome, distal to 21q22.2 We assessed the copy number of five chromosome 21 sequences (SOD1, D21S17, D21S55, ETS2, and D21S15) and found that D21S55 was duplicated in both cases. By means of pulsed-field gel analysis and with the knowledge of regional mapping of the probes D21S17, D21S55 and ETS2, we estimated the size of the common duplicated region to be between 400 and 3000 kilobases. This region, localized on the proximal part of 21q22.3, is suspected to contain genes the overexpression of which is crucial in the pathogenesis of Down syndrome.

Chromosome Banding↗
PubMed1989

Specificity of melphalan-induced rearrangements and their transmission through cell divisions.

The clastogenic effect of melphalan, an alkylating agent frequently used in chemotherapy, was investigated using chromosomes from human lymphocytes, two and three cell cycles after treatment in vitro. chromosome aberrations were much more frequent than chromatid type anomalies. Unbalanced rearrangements, i.e. deletions, dicentrics and complex rearrangements (in decreasing order of occurrence), were quite frequent and balanced rearrangements, such as reciprocal translocations and inversions, were quite rare. Deletions principally affected chromosomes 9, 5, 7 and 11. By comparison to the results obtained at first division after treatment, the relative frequencies of del(5) and del(20) increased with the number of cell divisions. Thus, these deletions were poorly eliminated by selection. This finding may be related to the fact that del(5) and del(20) are frequently observed in premalignant haemopathies.

Adult↗
PubMed1988

Acquired chromosome rearrangements in human lymphocytes: effect of aging.

A prospective study of structural rearrangements occurring in normal lymphocytes was carried out. For each of two newborns and four young and two old adults, about 1000 metaphases from 72-h and 120 from 48-h cultures were studied. The frequency of rearrangements between bands 7p14, 7q35, 14q11.2 or 14q12 and 14qter, which is on the average about 0.003, is higher in newborns (0.0043) than in adults (0.0024). Conversely, the rearrangements involving other bands, which have a frequency of 0.025 on the average, are more frequent in old adults (f = 0.038) than in young adults (f = 0.025) and newborns (f = 0.013). The first type of rearrangement, which occurs in utero, may correspond to immunoglobulin and related gene rearrangements. The other rearrangements seem to accumulate progressively and may reflect exposure to mutagens. It is import to discriminate these two types of rearrangements when studying the effect of low doses of mutagens.

Adult↗
PubMed1988

Diagrammatic representation for chromosomal mutagenesis studies. IV. Radiation-induced rearrangements in Ateles sp. (Primate, Platyrhini).

In order to study the induction of rearrangements by gamma-rays in relation to chromosomal size and morphology, experiments were conducted in an Ateles, a species with a rather unusual karyotype among primates. It possesses some very large chromosomes, which tend to be too rarely affected, especially by intrachanges like inversions. Both their large size and their characteristic banding pattern suggest that this low involvement is not due to difficulty of analysis. This suggests very strongly that chromosomal involvement in rearrangements is not a function of size. The possible role of other factors involved in chromosomal rearrangements like chromosome position during interphase are discussed.

Animals↗
PubMed1987

Human chromosome 22.

The acrocentric chromosome 22, one of the shortest human chromosomes, carries about 52 000 kb of DNA. The short arm is made up essentially of heterochromatin and, as in other acrocentric chromosomes, it contains ribosomal RNA genes. Ten identified genes have been assigned to the long arm, of which four have already been cloned and documented (the cluster of lambda immunoglobulin genes, myoglobin, the proto-oncogene c-sis, bcr). In addition, about 10 anonymous DNA segments have been cloned from chromosome 22 specific DNA libraries. About a dozen diseases, including at least four different malignancies, are related to an inherited or acquired pathology of chromosome 22. They have been characterised at the phenotypic or chromosome level or both. In chronic myelogenous leukaemia, with the Ph1 chromosome, and Burkitt's lymphoma, with the t(8;22) variant translocation, the molecular pathology is being studied at the DNA level, bridging for the first time the gap between cytogenetics and molecular genetics.

Abnormalities, Multiple↗
PubMed1987

[Mosaic tetrasomy 12p. Identical nature of the Pallister syndrome, the Teschler-Nicola/Killian syndrome and mosaic tetrasomy 21].

In two cases, first interpreted as mosaic tetrasomy 21, the R banding and the gene dosage studies lead us to conclude to a mosaic tetrasomy 12 p. In Pallister mosaic syndrome and in Teschler-Nicola/Killian syndrome, the very similar clinical signs and the identical abnormal chromosome, missing in leucocytes, led us to conclude that Pallister and Teschler-Nicola/Killian syndrome, as well as mosaic tetrasomy 21 are one and the same syndrome tetrasomy 12 p. This tissue limited mosaic is probably more frequent than it is assumed. Prenatal diagnosis can be made since the supernumerary chromosome is found in amniocytes. The distinctive tissue distribution is probably a selective process due to cellular differentiation gene, CD9 (or Alb 6) located to 12 p.

Aneuploidy↗
PubMed1986

Theoretical study of inversions affecting human chromosomes.

A theoretical study of inversions affecting human chromosomes is proposed. Taking into consideration the number of bands and the fact that breaks occur at interfaces between bands, it is concluded that: 7.659 different pericentric inversions might be detected in a prometaphasic 802-band karyotype; this number decreases to 917 in a metaphasic 273-band karyotype; 8.607 and 862 different paracentric inversions might be detected in the same karyotypes respectively, but these results are likely to be overestimated. These theoretical data are used for showing that the pericentric inversions detected in human cytogenetic laboratories, are too frequently recurrent and are not distributed at random.

Chromosome Inversion↗
PubMed1986

Inversions in evolution of man and closely related species.

By the comparative study of the karyotypes of many Primates, 35 inversions (25 peri- and 10 paracentric) having accumulated during evolution of species related to man were reconstructed. Some of them originated human chromosomes from more ancestral chromosomes still present in other primate species. Their detection in man would indicate the occurrence of reverse mutations. Other inversions occurred in ancestral chromosomes identical to those of man, and originated chromosomes of other Primates species. Their detection in man would indicate the occurrence of a convergent mutation. It is shown that such reverse and convergent mutations do occur. They are too frequently observed than by mere chance among patients ascertained in human cytogenetic laboratories. Their excess is still larger among radiation induced inversions in human cells. This demonstrates the nonrandom occurrence of inversions. In addition, it is concluded that inversions which have accumulated during evolution are more representative of mutagenesis than those detected in human cytogenetic laboratories.

Animals↗
PubMed1985

Inversion (14)(q12qter) or (q11.2q32.3): the most frequently acquired rearrangement in lymphocytes.

In a large study of chromosome rearrangements occurring in human lymphocytes from normal subjects, inv (14)(q12qter) or (q11.2q32.3) is found to be the most frequent, affecting 0.15% of mitoses. The same inversion is observed in the lymphocytes of the chimpanzee, indicating the ancestry of this inversion. It is not induced by ionizing radiations, and its frequency may be increased in Fanconi anemia, but not in ataxia telangiectasia. It may represent one of the steps of the process of leukemogenesis.

Animals↗
PubMed1985

Diagrammatic representation for chromosomal mutagenesis studies. III. Radiation-induced rearrangements in Pan troglodytes (chimpanzee).

A qualitative study is presented of chromosomal rearrangements induced by gamma-irradiation at 2 Gy and 3 Gy in peripheral blood lymphocytes of the chimpanzee Pan troglodytes. From a sample of 460 cells, karyotyped after R-banding, 1047 rearrangements were detected. Each type of rearrangement is analyzed according to the diagrammatic method previously developed. The non-random nature of the induction of the rearrangements is clear. The chimpanzee seems highly sensitive to the induction of dicentrics. This may be related to the existence, in its karyotype, of sensitive juxta-telomeric heterochromatin, much more frequently affected in the case of formation of dicentrics than of other types of rearrangements. Thus, the evaluation of radiation sensitivity of a given species based only on the yield of dicentrics may not have a general value for chromosomal mutagenesis.

Animals↗
PubMed1985

Mosaic tetrasomy 12p.

Mosaic tetrasomy 12p is a dysmorphic syndrome which has been described under the name of Pallister mosaic syndrome and Teschler-Nicola/Killian syndrome and has sometimes been incorrectly interpreted as tetrasomy 21. Here we report the first case to be diagnosed prenatally and confirmed by enzyme assays, and we summarize the clinical and biological characteristics of all the cases reported so far under various names.

Abnormalities, Multiple↗