Biomedical subjects

M Benkhalifa

Publications and source records attributed to M Benkhalifa.

23 records · Page 2Linked to original sources

PubMed1993

Karyotype and FISH analysis of a newly established cell line derived from a human bladder carcinoma.

A new human malignant urologic cell line was established in vitro from a moderately differentiated transitional cell carcinoma of the bladder and cytogenetically characterized. Repeated chromosome analyses of the cell line using conventional RHG and GTG banding and non-radioactive in situ hybridization showed a stable karyotype with a modal number of 48 and chromosomal rearrangements, some of which have not been previously described. Numerical deviation included three trisomies (+7, +8, +9) and one nullisomy (-19, -19). Structural changes involved a balanced translocation (1;5)(q12;q12), an isochromosome 3q, a 14p+, and two markers. Fluorescence in situ hybridization (FISH), using biotin-labeled alpha satellite probes for chromosome 9 or painting for chromosomes 1 and 8, applied to interphase nuclei or metaphases showed similar results to those found by conventional cytogenetic study. This cell line may be an interesting model for fuller characterization by molecular biology studies and for testing anti-cancer drugs in vitro.

Aged↗

PubMed1993

Assessment of polyploidy in human morulae and blastocysts using co-culture and fluorescent in-situ hybridization.

Fluorescence in-situ hybridization with DNA probes for X, Y and no. 18 chromosomes was used to analyse human morulae (n = 13) and blastocysts (n = 41), obtained after co-culture on Vero cells. On the basis of the number of hybridization signals, the proportion of embryos with more than five polyploid cells was 30.8% for morulae and 29.3% for blastocysts. These values are similar to those for mixoploidy (mosaicism of diploid and polyploid cells) observed in blastocysts of animal species. The results were confirmed by scanning electron microscopy, which showed a wide variation in the size of blastocyst nuclei, and by classical cytogenetic analysis. Mixoploidy seems to be a normal feature in preimplantation embryos and to occur very early in human embryo development. This lays open to doubt the preimplantation diagnosis of genetic errors at these stages, since results obtained from single cell analysis may not be representative of the whole embryo.

Animals↗

PubMed1992

Chromosome analysis by image processing in a computerized environment. Clinical applications.

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.

Chromosome Aberrations↗

PubMed1992

A method for cytogenetic analysis of boar spermatozoa using hamster oocytes.

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.

Animals↗

PubMedDate not supplied

[A preliminary study to assess the value of the DNA chips SpectralChip to detect subtle constitutional chromosome imbalances].

Comparative genomic hybridization on a microarray (microarray-CGH) allows to detect genomic chromosome imbalances. In order to assess its value to detect small chromosome imbalances observed in a clinical setting, using a DNA chip available commercially (Spectral Genomics, Houston, Texas, USA), we studied the DNA of 9 patients carrying a well characterized chromosome imbalance and the DNA of 11 patients where cytogenetic techniques such as high resolution banding karyotype, FISH using subtelomeric probes and comparative genomic hybridization on metaphase chromosomes conclude to a normal and/or balanced karyotype. A result was obtained for 19/20 patients. Failure of hybridization was observed for one patient. For all the other cases the sex of patients was correctly identified. Microarray-CGH was able to correctly diagnose the chromosome imbalance in 6/8 patients carrying such a defect i.e 9/11 imbalances (deletion or duplication) were detected. No chromosome imbalance was observed in 11 patients considered normal and/or balanced using cytogenetic techniques. Several clones were found to be polymorphic and required FISH studies to eliminate duplication or deletion. In conclusion, we think that this commercially available DNA chip might be useful to screen for chromosome imbalances. However, technical improvements are still necessary before using it in a clinical setting. Also, further studies are necessary to assess its sensitivity and specificity.

Chromosome Aberrations↗