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PubMed1989

[Microspectrophotometric DNA analysis in ulcerative colitis with special reference to its application for cancer and dysplasia diagnosis].

The DNA content was measured by microspectrophotometry from 100 specimens in 60 patients with ulcerative colitis including six complicating carcinoma. In dysplastic 23 (77%) of 30 samples showed aneuploidy or polyploidy, whereas in non-dysplastic tissues 50 (94%) of 53 samples were diploid, the difference being statistically significant. Polyploidy was often observed in the non-dysplastic mucosa of the patients complicating cancer or dysplasia. In non-dysplastic patients all samples with inflammation showed diploidy, however 10% of samples without inflammation showed polyploidy. A good correlation was found between the incidence of polyploid cells and the grade of dysplasia. From this study it was assumed that microspectrophotometric measurement of DNA content is useful in the assessment and diagnosis of dysplasia in ulcerative colitis and can be available in the screening of high-risk patients.

Adult↗
PubMed1984

[DNA content in cells of spontaneous hepatomas in CBA mice].

The DNA content was measured in the cells of 37 well-differentiated spontaneous hepatomas from 20 CBA mice aged 18 to 22 months. In all the cases, the DNA distribution pattern was polymodal, with the class of tetraploid cells being predominant. It was independent of the tumor ability to produce AFP. No signs of aneuploidy were noted. The cells of spontaneous hepatomas were characterized by a high level of polyploidy and by a dramatic reduction in the number of binuclear cells as compared with liver cells. A tendency was recorded toward positive correlation between the degree of cellular polyploidy and tumor size. The high level of polyploidy seen in spontaneous hepatomas which is also characteristic of the normal liver is considered to be a sign of tumor maturity.

Animals↗
PubMed1998

Genetic effects of petroleum fuels: II. Analysis of chromosome loss and hyperploidy in peripheral lymphocytes of gasoline station attendants.

Molecular cytogenetic methods were applied to investigate the effect of the occupational exposure to low concentrations of benzene and petroleum fuels on genomic stability. Twelve male gasoline station attendants (average benzene exposure of 0.32 mg/m3 as 8h TWA) and 12 age- and smoking-matched unexposed controls were selected for the study. The incidence of hyperploidy and polyploidy in peripheral lymphocytes was evaluated through in situ hybridization of interphase cells, harvested 24 hr after stimulation, with centromeric probes of chromosomes 7, 11, 18, and X. For half of the subjects, metaphases harvested 24 hr later were analyzed. The incidence of chromosome loss in vitro was determined in cytokinesis-blocked cells, harvested at 66 hr, through the hybridization of micronuclei with a pancentromeric probe. Ten thousand chromosomes (more than 200 metaphases equivalent) and 2,000 binucleated cells/person were scored for hyperploidy and micronucleus analysis, respectively. The results obtained did not show any exposure-related excess of hyperploidy or micronucleus formation. Conversely, the age of the subjects was significantly correlated with several markers of genomic instability, such as the incidence of chromosome X and chromosome 18 hyperploidy, total hyperploidy and polyploidy, and close to statistical significance with chromosome loss. Smoking habits did not appear to contribute significantly to the effects measured. The parallel analysis of hyperploidy and polyploidy in interphase nuclei in 24-hr cultures and in metaphase cells harvested 24 hr later showed basically similar incidences of aneuploid cells, indicating that no significant selection against hyperploid and polyploid types occurred during the first cell cycle in vitro.

Air Pollutants, Occupational↗
PubMed2024

Interspecific transfer of genetic information through polyploid bridges.

Hybridization blurs species boundaries and leads to intertwined lineages resulting in reticulate evolution. Polyploidy, the outcome of whole genome duplication (WGD), has more recently been implicated in promoting and facilitating hybridization between polyploid species, potentially leading to adaptive introgression. However, because polyploid lineages are usually ephemeral states in the evolutionary history of life it is unclear whether WGD-potentiated hybridization has any appreciable effect on their diploid counterparts. Here, we develop a model of cytotype dynamics within mixed-ploidy populations to demonstrate that polyploidy can in fact serve as a bridge for gene flow between diploid lineages, where introgression is fully or partially hampered by the species barrier. Polyploid bridges emerge in the presence of triploid organisms, which despite critically low levels of fitness, can still allow the transfer of alleles between diploid states of independently evolving mixed-ploidy species. Notably, while marked genetic divergence prevents polyploid-mediated interspecific gene flow, we show that increased recombination rates can offset these evolutionary constraints, allowing a more efficient sorting of alleles at higher-ploidy levels before introgression into diploid gene pools. Additionally, we derive an analytical approximation for the rate of gene flow at the tetraploid level necessary to supersede introgression between diploids with nonzero introgression rates, which is especially relevant for plant species complexes, where interspecific gene flow is ubiquitous. Altogether, our results illustrate the potential impact of polyploid bridges on the (re)distribution of genetic material across ecological communities during evolution, representing a potential force behind reticulation.

Polyploidy↗
PubMed1976

Chromosomes and causation of human cancer and leukemia. XIII. An evaluation of karyotypic findings in erythroleukemia.

This study was an attempt at defining the cytogenetic features of erythroleukemia (EL), particularly as related to the group of AML patients with MAKA (major karyotypic abnormalities), which generally were caused by three or more cellular events of translocation or nondisjunction. Eight of the 17 patients with MAKA had a diagnosis of EL or possible EL. In most cases, MAKA was featured by hypodiploidy, karyotypic instability, and polyploidy in the leukemic cells. The most common abnormalities were loss of B or G group chromosomes and gain of a no. 16 or one or more marker chromosomes. Each of the markers of 2q+, Dq+, mar(A2, st), mar(C12, M), r(?F) and minute metacentric and acentric markers was observed in two or more patients. The extent of polyploidy seemed to be correlated with the proportion of erythroid precursor cells in the marrow and with the karyotypic instability. Since the patients exhibited the same chromosomal features, whether or not they had a diagnosis of EL or possible EL, and since patients without such a diagnosis also had cytologic suggestions of EL, a close relation of MAKA to EL is assumed. It is believed that patients with MAKA constitute one of the three chromosomally classifiable groups of EL.

Bone Marrow↗
PubMed1993

Progression of signet ring cell carcinomas in the human stomach.

BACKGROUND: Stomach cancers show various growth patterns. It remains to be clarified how this variability is related to the genetic changes that occur during tumor progression. METHODS: To estimate the genetic changes from tumor ploidy, maps were made (using DNA cytofluorometry of metaphase cells in histologic sections) of 39 advanced signet ring cell carcinomas of the human stomach and correlated with tumor stage and the size of the primary mucosal lesion. RESULTS: Aneuploid area and multipattern aneuploidy were particularly common in advanced cancers with primary mucosal lesions smaller than 2 cm in diameter, of which a large portion were predominantly aneuploid and already diffusely infiltrating. As the tumor stage advanced, the incidence of aneuploidy in the mucosal lesion increased, whereas predominantly aneuploid tumors were less common as primary mucosal lesions became larger. Purely diploid areas with an incidence of polyploidy as low as in early cancers were common in advanced cancers. In addition, there were diploid-appearing cancer cells that infiltrated diffusely and were accompanied by polyploid as often as aneuploid cells. Some of these were aneuploid at the chromosomal level. CONCLUSIONS: In signet ring cell carcinoma, aneuploid cells show higher invasive activity toward the extramucosal part and may occur incidentally in originally diploid tumors, depending on the degree of genetic instability. An analysis of polyploidy is useful for differentiating cytometrically diploid (but actually, aneuploid) cells from diploid cells with minor genetic abnormalities.

Adenocarcinoma, Mucinous↗
PubMed2003

Tetraploid development in the mouse.

Spontaneous duplication of the mammalian genome occurs in approximately 1% of fertilizations. Although one or more whole genome duplications are believed to have influenced vertebrate evolution, polyploidy of contemporary mammals is generally incompatible with normal development and function of all but a few tissues. The production of tetraploid (4n) embryos has become a common experimental manipulation in the mouse. Although development of tetraploid mice has generally not been observed beyond midgestation, tetraploid:diploid (4n:2n) chimeras are widely used as a method for rescuing extraembryonic defects. The tolerance of tissues to polyploidy appears to be dependent on genetic background. Indeed, the recent discovery of a naturally tetraploid rodent species suggests that, in rare genetic backgrounds, mammalian genome duplications may be compatible with the development of viable and fertile adults. Thus, the range of developmental potentials of tetraploid embryos remains in large part unexplored. Here, we review the biological consequences and experimental utility of tetraploid mammals, in particular the mouse.

Animals↗
PubMed2007

Bleomycin-induced DNA damage and repair in Xenopus laevis and Xenopus tropicalis.

Microgel cell electrophoresis has been used with various species to measure breakage of DNA and DNA repair following exposure to the radiomimetic antibiotic, bleomycin. With humans, a high degree of DNA damage is considered to be predictive of cancer susceptibility. Non-isogeneic Xenopus laevis, the South African clawed toad, rarely develop spontaneous or induced cancers. Here, we investigate bleomycin-induced DNA damage and repair in splenic lymphocytes of this species to test consistency with cancer predictability. As X. laevis is pseudotetraploid in nature, while Xenopus tropicalis is diploid, we additionally explore the effect of polyploidy on DNA damage and repair in these vertebrates. The results show that higher doses of bleomycin are required to induce comparable levels of DNA damage in both Xenopus species, than in humans. X. tropicalis, the diploid, is more bleomycin-sensitive than is X. laevis. Additionally, repair rates of damaged DNA of X. laevis lymphocytes are more rapid than those of X. tropicalis, although both are hours slower than human leukocytes. While no data exist on cancer susceptibility in X. tropicalis, the results suggest greater susceptibility to cancer than X. laevis, but less than in humans. Thus, polyploidy serves as a protection against DNA damage and allows more rapid repair.

Animals↗
PubMed1979

Physiology of polyploids.

Polyploidy, a multiplication of the whole chromosomal complement, is a very widespread phenomenon in higher plants. Natural polyploids have been suggested to be more successful than their diploid progenitors under certain conditions. This success may be due to "balance hybridity," i.e., the combination of the advantage of hybridity together with the balancing of excessive segregation and sterility by chromosome doubling, and possibly also to the effect of genome multiplication per se. The latter effect can be studied independently of the effect of other genetic changes only in autopolyploid newly derived from single ancestral strains. The existing knowledge on the effect of genome multiplication on the physiology of the plant is fragmentary and based on too narrow a representation of plant types; much of the information available on the effect of genome multiplication pertains to the tomato. Various aspects of polyploidy are discussed according to levels of function and organization: gene action, cell characteristics, growth substance, water balance, ion balance, stability of phenotypic expression and the response of polyploid plants to stress. Future work on the physiology of autopolyploid plants should be directed towards: (1) the investigation of more representative experimental systems that should include genetically homogeneous and heterogeneous species of both wild and cultivated plants; and (2) diploid-polyploid comparisons on the level of isolated tissues and cells, in addition to the whole plant.

Cell Cycle↗
PubMed1987

Polyploidization of the BTC-32 cell line from Triatoma infestans (Hemiptera, Reduviidae).

The cytophotometric evaluation of the Feulgen-DNA content of the BTC-32 cells at passage 160 after 6 days of growth demonstrated that polyploidy is relatively frequent in this cell line. 4C values were assumed to pertain to diploid nuclei at the S or G2 phases but also to polyploid nuclei at the G1 phase. Polyploidy in 4C nuclei is assumed to be attained by endomitosis. However, there are morphological indications that polyploidization in cells with an 8C-128C Feulgen-DNA content could result from cellular and nuclear fusions, possibly mediated by viral particles present in the cell culture. Micronucleation was also frequent; it was assumed to be promoted by viral action or deficiency in some culture medium nutrient. These nuclear characteristics should be considered when using the BTC-32 cell line for monitoring the action of infective agents or their products.

Animals↗
PubMed1990

DNA in human glioblastomas. A flow-fluorescence cytometrical examination of 96 tumors.

The Flow-Fluorescence Cytometric Method (FCM) was applied to investigate the DNA content and the ploidy outlines of each of 96 glioblastomas. No specific DNA pattern was detected, possibly because of the tangle morphology of these variable tumors. Due to their capricious growth the DNA distribution proved to fluctuate greatly. Thus, the series, arranged according to increased PI (proliferation index) values, exhibited a wide spread within a total range from 7.1-97.15% (mean 39.3%) PI. A threefold subdivision of main types (I-III) appears to be of practical use for clinical prognostic assessment: "diploid" tumors with a PI range up to 10% (N = 7) are followed by "abnormal" chiefly tetra- and hyper-tetraploid tumors up to PI values about 30% (N = 21). The third category includes cases showing excessive "aneuploidy" combined more and more with polyploidy and valid stemlines, up to the PI maximum of about 97 rel.% (N = 68). Thus, in 89 tumors clear pathological changes of DNA content can be decoded; of these 68 (76.4%) express a considerable aneuploidy and polyploidy respectively.

Adolescent↗
PubMed2003

Tetraploid Artemisia annua hairy roots produce more artemisinin than diploids.

Hairy root cultures of diploid Artemisia annua L. (clone YUT16) grow rapidly and produce the antimalarial sesquiterpene artemisinin. Little is known about how polyploidy affects the growth of transformed hairy roots and the production of secondary metabolites. Using colchicine, we produced four stable tetraploid clones of A. annua L. from the YUT16 hairy root clone. Analysis showed major differences in growth and artemisinin production compared to the diploid clone. Tetraploid clones produced up to six times more artemisinin than the diploid parent. This study provides an initial step in increasing our understanding of the role of polyploidy in secondary metabolite production, especially in hairy roots.

Artemisia annua↗
PubMed2005

Different cell cycle responses of wound healing protagonists to transient in vitro hypoxia.

Polyploidization is a process present in cells of many different human tissues. Since it is also prominent in human wound healing in vivo and in vitro, we focused on the influence of hypoxia on the cells' proliferation and polyploidization response. The proliferation response of two major cell types, involved in human wound healing, human dermal microvascular endothelial cells (HDMEC) and normal human dermal fibroblasts (NHDF) was quite similar in the in vitro setup: proliferation significantly decreased under the influence of 18 h of hypoxia and was reinitiated after 72 h of reoxygenation. The cells' response concerning their tendency towards the development of polyploidy was different: NHDF did not generate any polyploid cells, which stands in contrast to former in vitro studies with human wound-derived fibroblasts, but HDMEC were characterized by the presence of both mononuclear and binuclear tetraploid cells. The number of tetraploids was downregulated during hypoxia and increased during reoxygenation, accompanied by proliferation onset. The immunomicroscopic survey of HDMEC opened up a cell cycle model, which might be useful in the future to evaluate cell cycle modulations leading to polyploidy without the need to apply any additional cell cycle inhibitors.

Cell Cycle↗
PubMed1991

A new action for topoisomerase inhibitors.

Topoisomerases are known to aid DNA replication by breaking and resealing supercoiled DNA. Consequently, cells exposed to topoisomerase inhibitors before or during the S (DNA synthetic) phase of the cell cycle undergo abnormal DNA replication and become irreversibly blocked in the G2 (pre-mitosis) phase. We report that following a 4-h exposure to topoisomerase II inhibitors, murine erythroleukemic cells (MELC) do not form mitotic figures but exhibit a time-dependent progression into G2 (4N DNA) and greater than G2 (up to 8N DNA) stages of the cell cycle. Following exposure to the topoisomerase I inhibitor camptothecin, recovering MELC also exhibit greater than G2 polyploidy, but to a considerably lesser degree: mitotic figures are present and a subpopulation of cells resumes cycling. However, both topo I and topo II inhibitors induce maximal percentages of greater than G2 cells when synchronized MELC are in the G2/M phase at the time of exposure. This suggests that, in addition to their S-phase action, topoisomerase inhibitors can interfere with chromosome condensation during G2 and, in so doing, induce polyploidy.

Animals↗
PubMed1985

Clastogenicity of a male contraceptive, gossypol, in mammalian cell cultures with and without the metabolic activation by S9 mix.

The clastogenicity of a potential male contraceptive, gossypol, was examined in cultured Chinese hamster cells with and without the presence of a metabolic activation system (rat liver S9 mix). Gossypol at concentrations of 1, 5, and 10 micrograms/ml did not induce chromosome breakage either in the presence or absence of the S9 mix. The ability of this compound to induce chromosome breakage and polyploidy was further examined in human lymphocyte cultures. Neither increased frequencies of chromosome breakage nor polyploidy was found in lymphocyte cultures from two healthy donors. The present study indicates that gossypol does not cause genetic damage at the chromosomal level. This is consistent with previously reported findings that it does not produce mutations in the Ames test. Gossypol has been under clinical trial in China for years and shown to be effective in 99.9% of over 10,000 men tested with no or mild side effects. If this compound can be further proven to be "safe" and approved for world-wide use as a male contraceptive, it would be for the benefit of all mankind.

Animals↗
PubMed1992

Nuclear DNA content and nucleation patterns in rat cardiac myocytes from different models of cardiac hypertrophy.

Nuclear DNA content and number of nuclei were examined in cardiac myocytes isolated from controls and rats with volume and pressure overload hypertrophy to determine if haemodynamic overload alters these nuclear parameters. The experimental groups were comprised of normotensive (WKY) and Spontaneously Hypertensive rats (SHR). Additionally, Sprague-Dawley rats with aortic constriction (AC), pulmonary stenosis (PS), myocardial infarction (MI), and 5 month arteriovenous fistulas (F) were studied along with appropriate shams for each of these groups. Nuclear DNA content was measured from DAPI-stained nuclei using an image analysis microdensitometry system. Myocyte volume was measured with a Coulter Channelyzer system. Approximately 83% of the left ventricular myocytes from the SHR and WKY groups contained a diploid DNA content with the remainder being tetraploid. The remaining experimental and sham groups, all female Sprague-Dawley rats (SD), were approximately 93% diploid. The nucleation patterns differed slightly between rat strains with the SHR/WKY expressing approximately 85% binucleation, 14% mononucleation and 5% tri- or tetranucleation. All SD groups, control and hypertrophied, showed approximately 89% binucleation, and 10% mononucleation with the remainder being tri- or tetranucleated. In summary: (1) cardiac myocytes from SHR/WKY strains are predominantly diploid but to a lesser degree than myocytes from SD; (2) nuclear number follows the same pattern with SHR/WKY showing a smaller percentage of binucleated myocytes than SD myocytes; (3) neither the duration, severity, or type of overload caused a significant change in the extent of polyploidy in overloaded hearts from SD rats; and (4) the extent of polyploidy in cardiac myocytes from both the right and left ventricles of SHR and WKY animals does not differ statistically.

Animals↗
PubMed1993

Karyotypic analysis of CCRF-CEM and drug-resistant cell lines with stable and unstable ploidy.

Karyotypic studies were performed on methotrexate (MTX)- and vincristine (VCR)-resistant cell lines derived from the human T-cell leukemia CCRF-CEM cell line. We noted karyotypic selection and additional chromosome change associated with acquisition of drug-resistance. Furthermore, we observed that both the parental and MTX-resistant sublines, CEM/MTX R1-3, had a tendency to ploidy change. Karyotypic studies of malignant cells have shown that polyploidy is frequently a consequence of a single sporadic event, followed by growth and selection of the polyploid clone [1]. In this study, however, various karyotypic clones were identified with near- and pseudotetraploid karyotypes that appeared to be derived from different near- and pseudodiploid sidelines. Polyploidy was invariably associated with loss of at least two of the four chromosomes 8 whether the pseudodiploid sideline from which it was derived carried one or both chromosomes 8. In contrast, neither polyploid clones nor loss of chromosome 8 was noted in the CEM/VCR R cells.

Chromosome Aberrations↗
PubMed1985

Diploid and tetraploid grey treefrogs (Hyla chrysoscelis and Hyla versicolor) have similar metabolic rates.

We measured oxygen consumption of the diploid frog Hyla chrysoscelis and its recently evolved tetraploid cryptic species Hyla versicolor at rest and during forced locomotory exercise. We also measured whole-body lactic acid concentrations of individuals of the two species at rest and following 4 min of exercise. Contrary to predictions based on tissue-culture experiments, rates of organismal metabolism are not different in this diploid/tetraploid species pair: the diploid and tetraploid species did not differ in rates of oxygen consumption at rest or during exercise. Furthermore, whole-body lactate concentrations of frogs at rest and following forced locomotion were the same in the diploid and tetraploid species. For these species, polyploidy does not appear to be associated with lower maintenance costs at the level of the organism. However, polyploidy also does not appear to have metabolic consequences that would limit the behavioral or ecological repertoire of an anuran.

Aerobiosis↗