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The usefulness of chromosome analysis in clinical oncology.

Chromosome studies are useful in clinical oncology. They can help establish an accurate diagnosis, guide treatment, and determine the prognosis. The author discusses situations where chromosome studies are indicated.

Chromosome Aberrations↗

[A new system of chromosome analysis by image treatment: the chromoscan].

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.

Animals↗

A longitudinal study of human age-related chromosomal analysis in skin fibroblasts.

Previous chromosomal analyses related to human aging used mainly cross-sectional data on metaphase chromosomes. However, it is difficult to directly relate the cross-sectional results to the specific type(s) of chromosomal mutations possibly occurring within a specific individual with advancing age, because the unique genetic endowment of each individual for longevity might be a modulating factor. We therefore have performed, for the first time, a longitudinal study of both numerical and structural chromosome analyses of skin fibroblasts at interphase and at metaphase derived from eight donors participating in the Baltimore Longitudinal Study. We have used the FISH method with chromosome-specific DNA probes and the data on total aneuploidy of 17 different chromosomes in each of the 16 cell cultures (2 from each of eight individuals) indicate that significantly higher percentages of aneuploid cells are detected at interphase than at metaphase. Mostly, the levels of chromosome-specific aneuploidy increase with the donor's advancing age and, in most individuals, chromosomes 1, 4, 6, 8, 10, and 15 show significantly higher frequencies of aneuploidy at interphase than those of the 11 other chromosomes studied. Although the significance of relatively higher levels of aneuploidy of certain chromosomes with aging remains unclear, it is intriguing to note that some of these chromosomes, such as 1, 4, and 6, have already been assigned to harbor senescence genes and chromosome 8 is known to house the gene for Werner Syndrome (progeroid syndrome), which shows very limited proliferative capacity of fibroblasts. It is conceivable that the degree and/or type of chromosome-specific aneuploidy might have some gene dosage effects in the control of cellular proliferation and selection during aging. We also show that a combination of both interphase and metaphase aneuploidy analyses provides more comprehensive and insightful information on intraindividual cellular dynamics and chromosomal aneuploidy as a function of age. Occasionally, very small proportions of cells in two individuals showed age-related structural chromosome aberrations, such as an acentric fragment derived from an X chromosome and an achromatic gap in chromosome 7. Thus, a comparative analysis of both intra- and interindividual longitudinal studies is very useful in detecting the pattern(s) of chromosome-specific alterations with increasing age.

Adult↗

[Chromosome analysis using image processing. Recent aspects and perspectives].

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.

Chromosome Aberrations↗

Chromosome analysis of spleen and/or lymph nodes of patients with chronic myeloid leukemia (CML).

Origin and spread of the chromosomally abnormal cells that appear in chronic myeloid leukemia (CML) after transformation are unknown. Spleen and lymph node may be involved. In 16 patients with CML splenectomy and/or adenectomy were performed before or during the blastic crisis of the disease, followed by a chromosomal analysis of the cells from the removed organ. At the same time, the chromosomes of the blood cell and of the bone marrow were also analyzed. Analyses were done with R banding. The results show that an extramedullary clonal development with duplication of the Ph1 chromosome and other features occurred. From a cytogenetic standpoint, acute blastic phase of CML is frequently characterized by an increased number of chromosomes owing to preferential gain of additional chromosomes. This, then, would clearly point to extamedullary acute transition in CML.

Bone Marrow↗

New molecular techniques for chromosome analysis.

The advent of molecular genetic technology has significantly advanced knowledge about the structure of chromosomes and their behaviour during meiosis and mitosis, as well as delineating cytogenetic aberrations that cannot be identified by conventional chromosome analysis. Molecular cytogenetics, the visualization of genetic loci using the dynamic recombinant technology of fluorescence in situ hybridization (FISH), now provides the obstetrician and gynaecologist with increasingly important diagnostic and prognostic information heretofore unavailable. The technical principles underlying FISH are briefly discussed. Emphasis is placed on the clinical applications of FISH and technologies derived from FISH, in particular comparative genome hybridization, microdissection FISH and multiplex FISH. These technologies play increasingly significant roles in preimplantation and prenatal genetic diagnosis, in the identification of microdeletion syndromes, cryptic translocations and marker chromosomes, and in defining chromosome mosaicism. FISH and related technologies also constitute essential diagnostic modalities in follow-up of organ transplantation, in a variety of haematological disorders and in determining the amplification of oncogenes associated with specific forms of cancer and neoplasia.

Female↗

Chromosomal analysis in young vs. senescent human fibroblasts by fluorescence in situ hybridization: a selection hypothesis.

Almost all previous studies on chromosomal analysis related to in vitro aging of human fibroblasts were done using only metaphase chromosomes. However, this procedure may provide only partial information since the aneuploidy presumably hidden in interphase cells would remain undetected. For this reason, we have analyzed aneuploidy both at interphase and at metaphase. Female (IMR-90) and male (IMR-91) cells were grown from the lowest to the highest population doubling levels and aneuploidy analysis was done by FISH with alpha-satellite DNA probes of 15 autosomes and two sex chromosomes. Our data on total aneuploidy in young cells indicate that significantly higher proportions of cells with aneuploidy can be detected at interphase than at metaphase. This presumably indicates that during active division of young cells, more aneuploid than diploid cells are selected against entry to mitosis. In contrast, interphase senescent cells from both strains show significantly fewer aneuploid nuclei than do young cells at interphase. This probably indicates that during senescence, there is greater selective pressure in the culture against long-term survival of aneuploid cells than against survival of diploid cells. Our study shows that cellular dynamics with respect to aneuploidy involving various chromosomes differs significantly at interphase and at mitosis during in vitro aging of human fibroblasts, and we propose a 'Selection Hypothesis' as an explanation to our findings.

Aneuploidy↗

Chromosomal analysis of a diethylnitrosamine-induced tumorigenic and a nontumorigenic rat liver cell line.

A chromosomal analysis was performed on two cell lines which were derived from the liver of two rats exposed to diethylnitrosamine in vivo. The cells were obtained by collagenase perfusion of the liver at an early stage of development of ATPase-deficient putative preneoplastic populations, and propagated from foci of epithelial cells which started growth in vitro. Cell line CL 38 proved to be tumorigenic after transplantation into nude mice, giving rise to hepatocellular carcinomas and metastases. Cell line CL 44 was nontumorigenic after transplantation into nude mice and was therefore considered preneoplastic. The diploid nontumorigenic line CL 44, with a modal number of 42 chromosomes, showed a deletion of chromosome 1 and a translocation of chromosomes 3 and 14 [t(3q12;14q21)]. The hyperdiploid neoplastic cell line CL 38 has a modal chromosome number of 52 and showed tri- or tetrasomy of chromosomes 3, 7, 9, 11, and 12 and a marker chromosome that might have originated from aberrant chromosome 1. One or two homologues of chromosome 3 showed terminal deletions (q42, q41, or q35). In both cell lines rearrangements of chromosome 11 were observed [rob(11q;?) or +11 or -11 or del(11)(q12)]. Some of these karyotype abnormalities are located on the same chromosome as described for transplantable hepatomas and for other chemically induced tumors of the rat.

Animals↗

Quality control in routine chromosome analysis: prediction of total number of bands for the individual case analyzed.

In routine diagnosis it is of importance for each single analysis to provide information about the level of quality at which the chromosomal analysis has been performed. The number of bands counted can be used as a direct criterion for the level of quality. Statistical prediction methods via linear regression were employed in order to predict the total number of bands of a haploid set of the metaphase (TNB) from those of single chromosomes or pairs of chromosomes. It was demonstrated that TNB can be predicted successfully by counting bands on just one chromosome, where chromosomes C2, C4, C5 or C7 were found suitable for prediction. If pairs of chromosomes are used to predict TNB, we would recommend C4/C7, C5/C6, and C2/C9.

Chromosome Banding↗

[Chromosomal analysis of Venezuelan creole cattle].

In order to improve the animal production by artificial selection, the chromosomal analysis of 15 (9 bulls and 6 cows) Venezuelan Creole cattle--a well adapted dual purpose herd--was conducted. This particular herd has a low fertility related to a diminished non return rate. Heparinized peripheric blood cells were cultured rendering metaphase spreads and subsequently stained by the G- and C-banding techniques for identification of chromosomes. All bulls had the submetacentric Y chromosome characteristic of Bos taurus taurus. The 1/29 translocation was observed in 2 bulls (22.2% of all males studied). The fused chromosome showed a single centromeric block of heterochromatin. The presence of such translocation in the Creole sample associated with reduced cattle fertility, demonstrates the urgency to continue this kind of study, in order to determine the incidence of this problem in Venezuela.

Animals↗

Chromosome analysis of peripheral lymphocytes from persons exposed to radioactive fallout in Norway from the Chernobyl accident.

Chromosome analysis of peripheral lymphocytes from two Norwegian populations (44 reindeer herding South samis from Røros and Snåsa, 12 sheep farmers from Valdres) exposed to fallout from the Chernobyl accident were made. The doses from caesium through the years 1987-1991 were calculated based on whole-body measurements 134Cs and 137Cs giving a total cumulative mean internal dose of 5.54 mSv for the total group of 56 persons. Chromosome aberrations were within the normal range when compared with historical controls with the exception of dicentrics (0.3% per cell, which is a 10-fold increase) and rings (0.07% per cell). A dose-dependent increase in dicentrics and rings based on caesium exposure was not observed.

Air Pollutants, Radioactive↗

High resolution chromosome analysis of constitutional and acquired t(15;17) maps c-erbA to subband 17q11.2.

High resolution chromosome analysis was performed on bone marrow cells from four patients with acute promyelocytic leukemia and t(15;17), and in lymphocytes from two unrelated, phenotypically normal persons with an apparently identical constitutional translocation. Scrutiny of prophase-prometaphase chromosomes localized the breakpoints in all six cases to subbands 15q22.3 and 17q11.2. Molecular genetic studies have localized the oncogene c-erbA to chromosome #17 between the breakpoints of the constitutional and the acquired anomaly. The present results, therefore, map c-erbA to subband 17q11.2.

Chromosome Aberrations↗

Technical aspects and diagnostic problems of direct chromosome analysis using chorionic villus sampling in the first trimester.

This paper describes 18 months' experience of direct chromosome analysis applied to villi aspirated during the first trimester, using a catheter inserted trans-cervically. A total of 325 biopsy samples were analysed, and there was a diagnostic failure in 6 of these cases (1.8%). An abnormal karyotype was detected in 12 cases (3.8%); three of them were chromosome mosaics not confirmed on amniotic fluid cultures drawn between the 16th and 18th week of gestation. Cytogenetic control was performed on fetal tissues after voluntary abortion. There was a karyotype discrepancy between the placenta and the fetus in two cases out of the 12 mentioned above.

Adult↗

MetaChrome: An Open-Source, User-Friendly Tool for Automated Metaphase Chromosome Analysis.

DNA Fluorescence In Situ Hybridization (FISH) is an essential technique to study chromosome biology and genetics, enabling precise visualization of specific genomic loci to study structural abnormalities, gene mapping, and chromosomal rearrangements. High-Throughput Imaging (HTI) can automate the analysis of DNA-FISH chromosome images, but the accurate and automated segmentation of mitotic chromosomes and simultaneous colocalization of FISH signals remains a challenge. While several commercial automated karyotyping tools partially solve these issues, open-source software that effectively combines robust chromosome segmentation with comprehensive colocalization analysis capabilities remains necessary. To address this unmet need, we developed MetaChrome, an open-source software platform built around a graphical user interface and explicitly designed for automated metaphase chromosome analysis. MetaChrome leverages fine-tuned deep learning models to automate metaphase chromosome segmentation, together with colocalization analysis of chromosome-specific FISH probes and immunofluorescent-labeled proteins. Importantly, MetaChrome achieves enhanced segmentation accuracy compared to traditional image processing methods by adopting a Cellpose segmentation model fine-tuned with manually annotated metaphase chromosome datasets. The fine-tuned model ensures precise assignment of DNA-FISH spots to individual chromosomes in an automated manner. This facilitates rapid identification of chromosomal abnormalities, reduces human error, and advances high-throughput chromosome analysis workflows, addressing a key bottleneck in chromosome biology research.

Chromosome segmentation↗

Sperm chromosome analysis in the father of a child with a de-novo reciprocal translocation t(11;15)(q12;q22) by G-banding and fluorescence in-situ hybridization.

Analysis of sperm chromosomes by G-banding and two-colour fluorescence in-situ hybridization (FISH) was carried out in the father of a child with a de-novo reciprocal translocation t(11;15)(q12;q22). Sperm chromosome complements were obtained after in-vitro fusion of zona-free hamster oocytes and donor spermatozoa. A total of 112 sperm complements was first analysed by G-banding. The frequency of structural chromosome aberrations (9.8%) and the conservative frequency of aneuploidy (0.0%) were not significantly different from those obtained in our control donors. The proportions of X-bearing (53.2%) and Y-bearing (46.8%) spermatozoa were not significantly different from the expected 1:1 ratio. A total of 313 sperm complements was analysed by two-colour FISH. The frequency of structural abnormalities for chromosomes 11 and 15 was 3.2 and 0.3% respectively. The frequency of rearrangements for chromosome 11 was statistically significant when compared with control donors (0.4%) (P < 0.0001). No spermatozoa with the t(11;15)(q12;q22) translocation were observed, showing no evidence for a germ-cell mosaicism. These results suggest that the de-novo involvement of chromosome 11 in a structural rearrangement is not random, and that in this patient an increased risk of de-novo structural chromosome abnormalities in further offspring does exist.

Adolescent↗