Biomedical subjects
Publications and source records attributed to P Malet.
A bladder carcinoma cell line, RT112/84, has been cytogenetically characterized by classical techniques and fluorescence in situ hybridization. The RHG banding and FISH analysis revealed a mixture of two clones and multiple chromosome rearrangements.
Interphase fluorescence in situ hybridization (FISH) with chromosome 21-specific cosmid clones was used to identify trisomy 21 in cultured and uncultured amniotic cells. Two novel site-specific cosmid clones (regions 21q22 and 21qtel) were compared with a cosmid contig (Zheng et al., 1992). Correct identification of chromosome 21 copy number was made in 65-75 per cent of trisomic cells and in 70-75 per cent of normal disomic cells by using all the tested probes. However, the chromosome 21-specific telomeric probe (cos 17F8) showed the best results due to more intense and clearly visible hybridization. Utilization of a directly fluorophorated telomeric probe using Cy3-dCTP and FluorX-dCTP allows accurate detection of chromosome 21 in a fast 'one-step' FISH procedure on uncultured interphase nuclei. In addition, we compared the efficacy of FISH analysis for the total population of interphase cells and cells in the post-replication (late S, G2) periods of the cell cycle. Selective scoring of cells in the post-replicative period (showing a pair of hybridization signals on each chromatid of the replicated interphase chromosome) increased the number of informative nuclei by up to 95-97 per cent. This approach allows cells with overlapping chromosomes, artificial double hybridization signals on separate chromatids in interphase chromosomes, background hybridization, and polyploid cells to be analysed. Application of directly labelled telomeric cosmid probes and integral analysis of hybridized nuclei in the pre- and post-replication periods of the cell cycle may help to further improve the prenatal detection of trisomy 21.
A method of in situ hybridization is described for rapid characterization of cytogenetical translocations. In the same experimental procedure, biotinylated centromeric and 'painting' DNA probes were used in combination. Signals of the double-target hybridization were visualized by only one fluorescein. This technique also permits a simultaneous detection of multiple unrelated aberrations involving several chromosomes.
A 13 year old girl referred for chromosome analysis because of disproportionate short stature (short neck, curved legs, pectus excavatum) with an initial clinical diagnosis of Turner's syndrome was found to have the karyotype 46,X, + der(X) in 100% of her blood lymphocytes. By means of conventional differential staining (QFH/AcD, FPG, and RBA banding) supplemented with distamycin A treatment, the karyotype of the proband was interpreted as 46,X,t(X;Y) (p22.3;q11). The rearranged marker X chromosome was found to be active in 91% of lymphocytes studied. PCR analysis with Y chromosome specific oligoprimers showed the presence of some Y chromosome long arm DNA in both lymphocyte and gonadal tissue biopsy cells. At laparoscopy the patient was found to have small gonads with a rudimentary uterus and fallopian tubes. Histological examination of gonadal tissue showed primary follicles with dystrophic changes of the germ cells and numerous follicular cysts (polycystic ovaries). The proband's phenotype and its correlation with the genetic imbalance of the rearranged X chromosomes, as well as with non-random t(X;Y) chromosome inactivation, are briefly discussed.
Transitional cell carcinomas of human urinary bladder were studied by interphase fluorescence in situ hybridization (FISH). With current hybridization to isolated nuclei, 26 tumors were investigated and nonrandom +7, -9 and -10 were identified. Monosomy 11, tetraploidies and polyploidies were detected in invasive and poor-differentiated tumors. Hybridization on frozen sections offers another means of analysing surgical samples. FISH to vesical washings can be applied to monitor tumor progression. Hybridizations on paraffine sections and on tissues previously stored in liquid nitrogen allow retrospective studies of the archived materials. Our data suggest that the interphase FISH can become a powerful tool for cytogenetic studies of bladder cancer.
Dealing with a routine regional cytogenetic activity, we have developed and adapted to clinical work a semi automatic karyotyping machine. Attempts for an accurate automated chromosome classification using a neural network have led to partial results. A specific adaptation to cancer cytogenetics is under development (determination of the modal number, translocations analysis with densitometric curves, automatic identification of markers). A specific program allows quantification of chromosome labelling with radioactive probes. Exchanges of digitized karyotypes are feasible with labs using automated karyotyping machines. A local network connects several karyotyping and metaphase finding stations. Guidelines for an international data bank concerning abnormal chromosome images have been elaborated. On the other hand the ISH techniques have been applied to the following topics: identification of human chromosome aberrations in amniotic and chorionic cells, chromosome studies of human gametes and embryos (including sex determination), identification of markers in cancer cells.
During a gestation with oligoamnios and growth retardation noticed at 25th week an amniocentesis allowed us to discover the 14th case of complete trisomy 9, the third detected in utero. It is also the first without heart malformation, otherwise phenotype was usual. The liver had small areas of necrosis with calcifications and slight fibrosis which may be in relation with two cordocentesis made before expulsion. The important phenotype alterations and poor outcome of fetuses with trisomy 9 justify elective abortion.
In this paper, the authors detail a method for displaying boar spermatozoa chromosomes using heterospecific zona-free hamster oocyte penetration technique. Semen samples from two Large-White boars having a normal spermogram were studied. The first one had a normal karyotype (38,XY), the second carried a reciprocal translocation rcp(3;7)(p1,3;q2,1). After in vitro fertilization by capacitated sperm, culture and cytogenetic analysis of hamster eggs we obtained metaphase spreads of spermatozoa chromosomes. The ratio of X- and Y-bearing spermatozoa was 49.2% and 50.8%, respectively.
After a brief description of the automatic metaphase finding and karyotyping systems actually available, the authors describe an interactive method for chromosome analysis. The edges of each chromosome are delineated automatically. The use of 256 grey levels and 512 x 512 pixels allows the accurate classification. The result may be recorded on hard copy, videotape or disk. Present improvements of the Chromoscan include histograms, quantitative studies and the use of an expert system.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Chromosomic alterations can be observed after the effect of a antimitotic amsidine on metaphases of cultured human lymphocytes: gaps, breaks, exchange figures, deletions, rings. Moreover we notice, among these cells, particular lines of big sized lymphoplasmocytoid cells, whose rate is abnormally high when compared to reference cultures.
The authors present a new interactive system for chromosome analysis. All the operations are checked by the biologist with the use of a "mouse". This system avoids the photographic work and the manual classification. Its main interest is to carry out quickly the karyotype after the slide preparation.
Chorionic villi cell cultures is a complement to direct chromosome analysis. It is indispensable for the determination of certain enzymatic activities. A rapid, simple and reliable method of culture is described which allows height quality karyotyping in a week. Confusion with maternal cells is a possible source of error. The authors identified and described these maternal cell types.
A patient with Philadelphia (Ph) chromosome positive chronic myelocytic leukemia is described who also developed an abnormality of chromosome #3, i.e., t(3;20)(p21;p13), in blast crisis. This abnormality may be connected with the advent thrombocythemia. The disease was a thrombopenia in the initial phase.
The myelodysplastic syndromes are a group of hematological disorders not yet clearly defined. The authors describe the chromosomal aspects of 20 cases observed in the region of Clermont-Ferrand in comparison with the bibliographical data.
Chorionic villi biopsies made during the first trimester of pregnancy allow an early prenatal diagnosis of many fetal abnormalities. The authors described a simple and rapid method of mesenchymal cells culture which have the advantage of improving the quality and number of the mitoses examined.
This work is an electron microscopic study of fibroblast culture of patients with metabolic diseases. In all cases, except for Niemann-Pick disease, primary lysosomes or secondary lysosomes containing lamellar, rectilinear or curvilinear material are accumulated in cytoplasm of fibroblasts. Though clinical consequences of metabolic diseases are diverse, cellular injuries are relatively uniform. Then electron microscopic study would'nt allow the diagnostic of a metabolic disease but it can provide an orientation. In one case, the enzymatic defect is not determined with biochemical analyses though clinical observation is characteristic of a metabolic disease; only the electron microscopic study shows a lysosomal accumulation.