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PubMed2004

Commercial-scale sperm cryopreservation of diploid and tetraploid Pacific oysters, Crassostrea gigas.

Cryopreservation of sperm from tetraploid organisms (the possession of four chromosome sets) is essentially unexplored. This is the first cryopreservation study to address sperm from tetraploid Pacific oysters, Crassostrea gigas, and addresses the commercial production of triploid oysters (three chromosome sets). Initial motility, refrigerated storage of undiluted sperm, osmolality of extender solutions, sperm concentrations, equilibration time, and cryoprotectants of propylene glycol and dimethyl sulfoxide were evaluated with sperm from diploid and tetraploid oysters. Unlike most teleost fishes, in which the duration of active motility is typically brief, the motility of sperm from oysters lasts for hours. The present study showed that responses to treatment effects by sperm from tetraploids were different from diploids. The majority of tetraploid experiments resulted in less than 10% motility after thawing and less than 5% fertilization. The highest fertilization obtained for thawed sperm was 96% for sperm from diploid oysters and 28% for sperm from tetraploid oysters. Differential responses to treatments by sperm from tetraploid and diploid oysters may be due to differences in gonadal development. However, the use of cryopreserved sperm from tetraploid Pacific oysters produced 100% triploid offspring by fertilization of eggs from diploid females as determined by flow cytometry of larvae. This study demonstrates that sperm from tetraploid oysters can be collected, frozen, and stored for production of triploid offspring.

Animals↗

PubMed2006

An alternative method of deriving embryonic stem cell-like clones by aggregation of diploid cells with tetraploid embryos.

OBJECTIVE: To assess whether embryonic stem (ES) cells could be derived from the aggregation of diploid cells with tetraploid embryos. DESIGN: Randomized, prospective study. SETTING: University embryology and gamete biotechnology laboratory. ANIMAL(S): F1 (C57BL6/DBA2) mice. INTERVENTION(S): Four- to eight-cell F1 tetraploid embryos were aggregated with 10 to 15 donor E14 ES cells. MAIN OUTCOME MEASURE(S): Embryogenesis and ES cell establishment. RESULT(S): No difference (78% to 89%) in blastocyst formation was detected between the aggregated tetraploid and the control diploid embryos. In a total of 27 transfers, pregnancy was detected in three tetraploid (23.1%) and five diploid (35.7%) cases, and three live births developed from the aggregated tetraploid embryos. The tetraploid blastocysts without aggregation were plated, but no ES cell-like colony was formed. Six of eight aggregated blastocysts derived well-proliferated colonies, which were positive for anti-stage-specific embryonic antigen (SSEA)-1 antibody, Oct-4, and alkaline phosphatase. The microsatellite assay confirmed the homogenous makeup among the donor E14 cells and live-birth and ES-like cells derived from the E14-aggregated, tetraploid embryo. CONCLUSION(S): The aggregation of pluripotent diploid cells with tetraploid embryos yielded live births and ES-like cells that were homogenous to the donor diploid cells.

Animals↗

PubMed2006

Thyroid hormone profile during annual reproductive cycle of diploid and triploid catfish, Heteropneustes fossilis (Bloch).

Triploid fishes generally show sterility along with retarded gonadal development and aneuploid gametes. In teleosts, thyroid hormones influence seasonal adaptations and annual events such as reproduction. In addition, thyroid hormone deposition in matured ova is important for reproductive success as the role of thyroid hormones in early development and metamorphosis is well established. The present study deals with measurements of free and total thyroxine (T4) and triiodothyronine (T3) in the plasma of triploid and diploid catfish Heteropneustes fossilis (Bloch) in a complete reproductive cycle. Accumulations of total T4 and T3 within the oocytes have also been measured during the spawning period from fishes of both ploidy groups. No difference of plasma free hormones was noticed between the diploids and triploids of both the sexes in any period of reproductive cycle, although, seasonal variations were noted in both the groups. A significant decrease in the total thyroid hormone levels was noticed in plasma of the diploids in the spawning period compared to triploid fish. During the same period, accumulation of THs was significantly higher in the oocytes of diploids than that of the triploids. Thyroid gland structure also revealed a higher state of activity in the female diploids than the triploids during spawning period. Lower activity of thyroid tissue, higher levels of THs in plasma, and lower accumulation of maternally derived hormones in the oocytes of triploid females during spawning period may be associated with sterility of triploids.

Animals↗

PubMed2001

Comparative salt tolerance of amphidiploid and diploid Brassica species.

Salt (NaCl) tolerance of three amphidiploid Brassica species, B. napus (AC genome), B. carinata (BC genome), and B. juncea (AB genome), and their putative diploid relatives, B. campestris (A genome), B. oleracea (C genome) and B. nigra (B genome) was examined under glasshouse conditions. The plants were grown in sand culture throughout the study period (51 days). Twenty-three day old plants of all six species were subjected for 28 days to control (0 mol m(-3) NaCl), 100 and 200 mol m(-3) NaCl in Hoagland nutrient solution. Under saline conditions, growth of the three amphidiploid species was significantly greater in shoot and root weights, and seed yield was greater than that of the diploids. The amphidiploids accumulated lower Na(+) but higher K(+) in their shoots and roots, the K/Na ratio therefore being considerably higher than those of the diploids. Ca(2+) accumulation was similar in the diploids and amphidiploids, and the Cl(-) accumulation pattern was not consistent in the different species. The occurrence of high salt tolerance of amphidiploids, and their enhanced K/Na discrimination with respect to their diploid relatives, suggests that salt tolerance has been obtained from A and C genomes and the latter trait from all three genomes (A, B, and C).

Journal Article↗

PubMedDate not supplied

Improved serological response to human diploid cell rabies vaccine when given simultaneously with antirabies hyperimmune globulin.

BACKGROUND: The prevention of rabies in Mexico continues to be an important goal for the health sector. Although the prevalence of this disease continues to fall, between 1990 and 1995 a total of 238 cases were registered (an average of 40 cases annually), with a mean annual incidence of 0.04 cases per 100,000 inhabitants and a mortality of almost 100%, so that it is important to rely on highly effective vaccines with few side effects. The objective of this work was to evaluate seroconversion and tolerance to the human diploid cell antirabies vaccine administered to individuals with a history of exposure to rabies, to compare these results with those reported in the literature for the Fuenzalida vaccine, a rabies vaccine produced in the brain tissue of suckling mice, and to find the role antirabies hyperimmune gamma globulin plays in the concentration of post-vaccination antibody concentrations. METHODS: An analytical transverse study was carried out in 40 children and adults with a history of rabies exposure who were given a complete, five-dose intramuscular schedule of the human diploid cell rabies vaccine. Subjects were followed daily, and local and systemic signs and symptoms were recorded. Two blood samples (at baseline and at the end of the vaccination schedule) were taken and antibody titers against rabies glycoprotein, using the ELISA technique, were measured. RESULTS: Adverse side effects produced by the human diploid cell antirabies vaccine, such as frequency of pain, erythema, itching, and regional adenopathy were fewer than those reported in the literature for the Fuenzalida vaccine (p < 0.05), and of induration and local pain (p < 0.05) in relation to the latter vaccine. All patients seroconverted, producing geometric mean antibody titers of 6.22 IU/mL, an arithmetic mean titer of 9.66 IU/mL with a SD of 9.1 IU/mL. The level of tolerance to the diploid cell vaccine was good and its adverse effects were minimal and fewer than those reported for the Fuenzalida rabies vaccine. Patients receiving the diploid cell vaccine plus antirabies hyperimmune gamma globulin developed higher antibody titers (measured by ELISA test) at the end of the vaccination schedule than those only receiving the vaccine. CONCLUSIONS: These results are important in order to achieve an adequate and opportune level of protection provided by prophylactic vaccines to patients with exposure to rabies.

Adolescent↗

PubMed1998

Inhibitor and temperature effect on catalase in the liver of adult diploid and haploid Rana rugosa.

The authors succeeded in raising a single mature haploid Rana rugosa female to the age of 2 years from an egg artificially fertilized with ultraviolet-irradiated sperm. In order to discover why this particular haploid individual should survive so long, hydrogen peroxide detoxifying catalase in the liver of this individual and age-matched diploids was examined and compared for total activity, temperature stability, and chemical inhibition. Total activity was found to be significantly higher in the haploid frog than in the diploids, suggesting that this particular haploid had a unique system for hydrogen peroxide detoxification which protected the liver against cell death, preventing hepatic failure, and leading to a prolonged survival. Liver catalase from the haploid proved to be more labile to aminotriazole and urea, losing 60-70% of its original activity after 30 min treatment, whereas diploid catalase lost only 40% under the same conditions. Haploid and diploid catalase responded similarly to heat, however. It seems likely that inhibitor-binding sites differ considerably between the catalase of normal diploids and the catalase of this particular haploid, while overall structure is generally similar.

Amitrole↗

PubMed2002

Bromus fasciculatus presl--a third diploid progenitor of Bromus section Genea allopolyploids (Poaceae).

Allozyme variation of ten heterozymes of seven enzymes among five accessions of a rare diploid Bromus fasciculatus was analysed with the use of PAGE and compared with that for six other species of section Genea of the genus Bromus. Allozymes charasteristic for diploids B. tectorum and B. fasciculatus are combined in fixed heterozygous phenotypes of tetraploid B. rubens. Fixed heterozygous phenotypes of tetraploid B. madritensis combine one allozyme of B. fasciculatus with another of diploid B. sterilis at each of the loci studied. Of the three diploids studied, only B. sterilis fits well for a role of a genome donor for the polyploid B. diandrus-rigidus complex. Bromus fasciculatus thus appears to be a diploid ancestor for the two tetraploids of section Genea, B. rubens and B. madritensis.

Bromus↗

PubMed2002

Identification of diploid endosperm in an early angiosperm lineage.

In flowering plants, the developmental and genetic basis for the establishment of an embryo-nourishing tissue differs from all other lineages of seed plants. Among extant nonflowering seed plants (conifers, cycads, Ginkgo, Gnetales), a maternally derived haploid tissue (female gametophyte) is responsible for the acquisition of nutrients from the maternal diploid plant, and the ultimate provisioning of the embryo. In flowering plants, a second fertilization event, contemporaneous with the fusion of sperm and egg to yield a zygote, initiates a genetically biparental and typically triploid embryo-nourishing tissue called endosperm. For over a century, triploid biparental endosperm has been viewed as the ancestral condition in extant flowering plants. Here we report diploid biparental endosperm in Nuphar polysepalum, a basal angiosperm. We show that diploid endosperms are common among early angiosperm lineages and may represent the ancestral condition among flowering plants. If diploid endosperm is plesiomorphic, the triploid endosperms of the vast majority of flowering plants must have evolved from a diploid condition through the developmental modification of the unique fertilization process that initiates endosperm.

Diploidy↗

PubMed2006

A novel mating system analysis for modes of self-oriented mating applied to diploid and polyploid arctic Easter daisies (Townsendia hookeri).

We have developed a new model for mating system analysis, which attempts to distinguish among alternative modes of self-oriented mating within populations. This model jointly estimates the rates of outcrossing, selfing, automixis and apomixis, through the use of information in the family structure given by dominant genetic marker data. The method is presented, its statistical properties evaluated, and is applied to three arctic Easter daisy populations, one consisting of diploids, the other two of tetraploids. The tetraploids are predominantly male sterile and reported to be apomictic while the diploids are male fertile. In each Easter daisy population, 10 maternal arrays of six progeny were assayed for amplified fragment length polymorphism markers. Estimates, confirmed with likelihood ratio tests of mating hypotheses, showed apomixis to be predominant in all populations (ca. 70%), but selfing or automixis was moderate (ca. 25%) in tetraploids. It was difficult to distinguish selfing from automixis, and simulations confirm that with even very large sample sizes, the estimates have a very strong negative statistical correlation, for example, they are not independent. No selfing or automixis was apparent in the diploid population, instead, moderate levels of outcrossing were detected (23%). Low but significant levels of outcrossing (2-4%) seemed to occur in the male-sterile tetraploid populations; this may be due to genotyping error of this level. Overall, this study shows apomixis can be partial, and provides evidence for higher levels of inbreeding in polyploids compared to diploids and for significant levels of apomixis in a diploid plant population.

Asteraceae↗

PubMed1988

Clinical importance of near-diploid tumor stem lines in patients with osteosarcoma of an extremity.

We determined the clinical value of flow-cytometric measurement of tumor-cell DNA content, which reflects the chromosome number (ploidy), in patients with osteosarcoma of an extremity. Hyperdiploid stem lines were identified in 25 of 26 tumor samples obtained at diagnosis from patients who did not have clinically overt metastases. Near-diploid tumor stem lines coexisted with hyperdiploid lines in 15 of these 25 cases; an isolated near-diploid line was present in the 26th case. All 26 patients underwent definitive surgery and then were treated uniformly with intensive adjuvant combination chemotherapy. Kaplan-Meier analysis of both relapse-free and overall survival times showed that the presence of a near-diploid tumor stem line was associated with improved outcome (P = 0.003 for each comparison). After a median follow-up time of three years, pulmonary metastases developed in only 2 patients in the group with near-diploid lines, in contrast to 7 of the 10 with hyperdiploid lines exclusively. Near diploidy remained significantly associated with improved relapse-free survival after adjustment for the influence of age, the only clinical variable that showed prognostic strength in this analysis (P less than 0.01; relative risk, 0.08; 95 percent confidence interval, 0.02 to 0.48). Our findings demonstrate the usefulness of flow-cytometric determination of tumor-cell ploidy for predicting the sensitivity of histologically high-grade osteosarcoma to chemotherapeutic agents. Patients with a near-diploid tumor stem line can be expected to respond favorably to adjuvant chemotherapy as used in this study, whereas those with only hyperdiploid lines should be considered as candidates for alternative therapy.

Adolescent↗

PubMed1998

Diploid hybrid speciation in Penstemon (Scrophulariaceae).

Hybrid speciation has played a significant role in the evolution of angiosperms at the polyploid level. However, relatively little is known about the importance of hybrid speciation at the diploid level. Two species of Penstemon have been proposed as diploid hybrid derivatives based on morphological data, artificial crossing studies, and pollinator behavior observations: Penstemon spectabilis (derived from hybridization between Penstemon centranthifolius and Penstemon grinnellii) and Penstemon clevelandii (derived from hybridization between P. centranthifolius and P. spectabilis). Previous studies were inconclusive regarding the purported hybrid nature of these species because of a lack of molecular markers sufficient to differentiate the parental taxa in the hybrid complex. We developed hypervariable nuclear markers using inter-simple sequence repeat banding patterns to test these classic hypotheses of diploid hybrid speciation in Penstemon. Each species in the hybrid complex was genetically distinct, separated by 10-42 species-specific inter-simple sequence repeat markers. Our data do not support the hybrid origin of P. spectabilis but clearly support the diploid hybrid origin of P. clevelandii. Our results further suggest that the primary reason diploid hybrid speciation is so difficult to detect is the lack of molecular markers able to differentiate parental taxa from one another, particularly with recently diverged species.

Biological Evolution↗

PubMed1970

Distribution of labeled chromatin. I. M 1 and M 2 anaphases of diploid and tetraploid cultured mammalian cells.

The question of whether distribution of chromatids to daughter cells in mitosis is a random or nonrandom process was investigated by study of the distribution of labeled chromatin in anaphase pairs at M(1) and M(2) after a pulse of tritiated thymidine. Diploid and tetraploid rat and diploid human fibroblast-like cells in serial monlayer culture were synchronized by two different methods to "purify" M(1) and M(2) anaphases: metaphase shake, and FUdR block to DNA synthesis followed by exogenous thymidine. Exposed grains of NTB-2 emulsion were counted over M(1) and M(2) anaphase pairs. An analysis (by pair) of diploid M(2) anaphase grain counts showed two discrete populations of daughters with less and with more radioactivity. A similar analysis of diploid M(1) and tetrapolid M(2) anaphases showed a single grain-count distribution. These findings may support a nonrandom model of chromatid segregation for diploid mammalian cells but do not rule out random segregation until sound mathematical models are formulated for expected random grain distributions in M(2) anaphases of cells with differing numbers of chromosomes.

Analysis of Variance↗

PubMed2000

Genetics of Ustilago violacea. XXXV. Transposition in Haploid and Diploid Sporidia and Germinating Teliospores.

Ustilago violacea sporidia of the white (w) MAD strain (a-2 w lys-3 ino-1 thi) incubated on minimal medium containing 100 mM KClO3 (potassium chlorate) produced only colonies with the pink phenotype. Sporidia from these colonies retained their pink color on complex medium. Sporidia of the diploid D1 strain (a-1 y nic-1 thi/a-2 w met-1 arg-f Chl70 thi) and of the diploid D2 strain (a-1 y his-1 glu-1 thi/a-2 w lys-3 ino-1 thi) produced pink colonies on complex medium. Streaks of diploid D1 sporidia from the pink colonies were stable on complex medium. In contrast, streaks of diploid D2 sporidia, which are heterozygous for the MAD strain, were unstable, initially producing pink colonies on complex medium but then, with continued incubation, producing white termini. Sporidia from the white termini with diploid morphology continued to yield white colonies. Teliospore colonies from three crosses with the MAD strain as a common parent were uniformly pink or had a pink sector instead of the expected uniformly white colonies or colonies having a white sector. Four of 20 and 13 of 20 teliospore colonies, respectively, from two of the three crosses had both a-1 and a-2 sporidia, and the remaining colonies had only a-1 or only a-2 sporidia. All 40 teliospore colonies from the third cross had only a-1 or only a-2 sporidia. All of these observations indicated that the MAD strain may have two autonomous, transactive transposable elements in different chromosomes and that insertional mutations in at least two haplolethal loci were responsible for the teliospore colonies with only a-1 or only a-2 mating type. Crossing over between a haplolethal locus and the centromere would account for teliospore colonies with both a-1 and a-2 sporidia.

Journal Article↗

PubMed2004

Comparative ITS and AFLP analysis of diploid Cardamine (Brassicaceae) taxa from closely related polyploid complexes.

BACKGROUND AND AIMS: Diploid representatives from the related polyploid complexes of Cardamine amara, C. pratensis and C. raphanifolia (Brassicaceae), were studied to elucidate phylogenetic relationships among the complexes and among the individual taxa included. METHODS: Two independent molecular data sets were used: nucleotide sequences from the internal transcribed spacers (ITS) of nrDNA, and amplified fragment length polymorphism (AFLP) markers. Seventeen diploid taxa from the studied groups were sampled. KEY RESULTS: Both ITS and AFLP analyses provided congruent results in inferred relationships, and revealed two main lineages. While the C. amara group, consisting of C. wiedemanniana and four subspecies of C. amara, was resolved as a well-supported monophyletic group, taxa from the C. pratensis and C. tenera groups (the latter representing diploid taxa of the complex of C. raphanifolia) all appeared together in a single clade/cluster with no support for the recognition of either of the groups. Intra-individual polymorphisms and patterns of nucleotide variation in the ITS region in C. uliginosa and C. tenera, together with the distribution of AFLP bands, indicate ancient hybridization and introgression among these Caucasian diploids. CONCLUSIONS: The lack of supported hierarchical structure suggests that extensive reticulate evolution between these groups, even at the diploid level, has occurred (although an alternative explanation, namely ancestral polymorphism in ITS data, cannot be completely excluded). Several implications for the investigation of the polyploid complexes of concern are drawn. When tracing origins of polyploid taxa, a much more complex scenario should be expected, taking into account all relatives as potential parents, irrespective of the group in which they are classified.

Base Sequence↗

PubMed1990

Stimulation of DNA synthesis in carcinogen-induced diploid hepatocytes in vitro.

Diploid hepatocytes induced by a combination of diethylnitrosamine and 2-acetylaminofluorene were isolated and separated from polyploid hepatocytes by centrifugal elutriation. The diploid and polyploid cell fractions were approximately 90% pure and contained between 1 and 1.5 x 10(7) cells. When kept in monolayer cultures both cell populations responded to the mitogenic effect of EGF and insulin. However, the percentage of labelled nuclei was higher in predominantly diploid compared to predominantly tetraploid hepatocyte cultures at all epidermal growth factor (EGF) concentrations used in this study. At 10 ng EGF/ml and 10 mU insulin/ml the labelling index was twice as high in the diploid liver cells. Further work is required to show the relevance of the stronger response of the diploid cell fraction to mitogens in the process of carcinogenesis.

2-Acetylaminofluorene↗

PubMed1996

A comparison of the propensity for gene amplification between near-tetraploid and near-diploid V79 clones resistant to 150 nM methotrexate.

Among various 150-nM methotrexate-resistant (MTXr) V79 clones isolated, we found that two near-tetraploid clones as well as a near-diploid clone with amplification in the dihydrofolate reductase (dhfr) gene readily developed resistant to 40 000 nM MTX within 3 months during stepwise increased MTX selection, while two near-diploid clones without gene amplification could not acquire resistance beyond 5000 nM MTX. Then, we studied how the clones increased the resistance to MTX, and compared the propensity for gene amplification among three types of clones. Dot blot analysis showed that the acquisition of the high levels of resistance to MTX observed in two near-tetraploid clones and a near-diploid clone with gene amplification was associated with amplification in the dhfr gene. The amplified dhfr gene was overexpressed at mRNA and protein levels in the clones. Southern blot analysis of Hind III- and Eco RI-digested DNA in the clones at the time when they became resistant to 10 000 nM MTX indicated that they amplified the dhfr gene fragments which existed in low amounts in parental V79 cells, and that no gross rearrangement of the amplified dhfr gene was detected. Furthermore, fluorescence in situ hybridization analysis showed that the amplified dhfr gene was located on one chromosome as cluster(s). On the other hand, two near-diploid clones without gene amplification did not show any amplification of the dhfr gene even at 5000 nM-MTX resistant stage. These combined results suggest that the near-tetraploid clone as well as the near-diploid clone with the dhfr gene amplification have genomic instability with the propensity for gene amplification during stepwise MTX selection, and have a similar process for the development of the dhfr gene amplification.

Animals↗

PubMed1985

Irreversible depression in the ratio of tetraploid:diploid liver nuclei in rats treated with 3'-methyl-4-dimethylaminoazobenzene (3'M).

A reduction in the ratio of tetraploid to diploid liver nuclei has been investigated as an early indicator of hepatocarcinogenesis in the rat using the liver carcinogen 3'-methyl-4-dimethylaminoazobenzene (3'M). In a dose ranging study 3'M was administered by gavage to rats at 5, 12.5 and 25 mg/kg for up to 10 weeks and the following parameters studied: bodyweight gain, dye binding to hepatic protein, nuclear ploidy in liver and histopathology. Significant reduction in bodyweight occurred only with 25 mg/kg; dye binding to protein occurred in a dose-related manner; depression of the percentage of tetraploid nuclei compared with diploids was dose-related and effects were detected even at the lowest dose. These observations were consistent with those from previous studies by other investigators. In a separate experiment 3'M was administered at the maximum tolerated dose (MTD) of 25 mg/kg for 3 weeks, during which time there was a significant reduction in bodyweight gain and a reduction in the ratio of tetraploid:diploid liver nuclei. After cessation of dosing the rate of bodyweight gain returned to normal but there was no corresponding recovery of the ratio of tetraploid:diploid nuclei in the liver. A long-term continuous gavage study at 2.5 mg/kg revealed a time dependent reduction in the ratio of tetraploid:diploid liver hepatocyte nuclei and histopathological changes that included hepatocarcinoma were also observed. There was no correlation between the severity of pathological changes and the change in nuclear ploidy ratio in this experiment and it is concluded that the changes in ploidy ratio are related to the carcinogenic effect of 3'M and are independent of its gross toxicity.

Animals↗

PubMed1997

Clinicopathologic differences between diploid and tetraploid complete hydatidiform moles.

Complete hydatiform moles (CHM) may be are diploid or tetraploid. The proportions vary in the literature. To date, there has not been a systematic characterization of these two types. This study is a retrospective investigation of clinicopathologic differences between diploid and tetraploid CHMs. Thirteen formalin-fixed, paraffin-embedded CHMs were analyzed for DNA content by flow cytometry (FC). Using standard flow cytometric definitions, histograms were classified as FC-diploid or FC-tetraploid (4N peak > or = 15% of 2N peak and cell cycle events to 8N) and compared with respect to selected clinical and pathologic features. Eight CHMs (61%) met the criteria of tetraploidy by flow cytometry, although all five FC-diploid cases harbored minor (< 15%) tetraploid subpopulations. Patients with tetraploid moles were older (mean age 32.8 years vs. 19.6 years, p < 0.005), presented at lower preevacuation gestational ages (12.7 weeks vs. 15.4 weeks, p < 0.05), had higher mean serum beta-HCG levels (2.82 x 10(5) i.u. vs. 0.99 x 10(5) i.u., p = 0.07), and higher DNA S-phase fractions (17.9% vs. 7.0%, p = 0.002). No significant differences were found in other histological features. No moles recurred. In this small sample of CHMs, tetraploidy was common. Compared with the FC-diploid CHMs, FC-tetraploid CHMs occurred in older patients with lower gestational age, higher serum beta-HCG levels, and higher DNA S-phase fraction by flow cytometry.

Age Factors↗