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Results for “polyploidization”

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PubMed1980

Graded inhibition of cell disintegration of juvenile hormone.

The proventriculus of Galleria mellonella larvae consists of 260-300 polyploid cells. The cells grow throughout larval development and at each ecdysis produce a new cuticular lining of the proventriculus. Each cell secretes a large sclerotized plaque covered with thorns. At the end of the last larval instar, the cells disintegrate unless the larvae is treated with juvenile hormone or implanted with active corpora allata. Depending on the time of treatment and the hormone dose, these insects preserve their proventricular cells to graded degrees. In some cases, the cells continue to grow or at least preserve their full function, in other instances they secrete but small plaques with fewer thorns or a smooth cuticle without any thorns. Very late treatments preserve healthy cells incapable of secreting the cuticle.

Animals↗

PubMed1992

DNA cytometry in postirradiation cervical-vaginal smears.

Benign radiation change (BRC) in cervical-vaginal smears may be difficult to distinguish from postirradiation dysplasia (PRD) or recurrent cervical carcinoma. The utility of DNA analysis in postirradiation smears was evaluated retrospectively in 71 patients. Representative Papanicolaou smears were restained with a Feulgen method and 100 to 250 cells were analyzed for DNA content using the CAS 200 image analysis system. Thirty-three control irradiated patients had negative smears with a minimum 3-year follow-up. Thirty controls (91%) had diploid histograms with a mean coefficient of variation of 8.2% and an average of 6.8% of cells in S and G2/M phase. Three control patients had atypical nondiagnostic histograms. Twenty-three patients had abnormal smears and subsequent local recurrence; 21 (91%) had abnormal histograms, with seven showing polyploidy and 14 showing aneuploidy. The remaining 15 patients had abnormal smears diagnosed as PRD but no evidence of recurrent carcinoma. Five were polyploid, six were aneuploid, one was diploid, and three were atypical but nondiagnostic. Interactive DNA cytometry is useful in differentiating BRC from PRD and recurrent cancer. Aneuploidy is rarely, if ever, seen in negative smears with BRC. However, BRC may be associated with broad diploid peaks and increased proliferating cells. An abnormal histogram can be seen with PRD and does not always correlate with recurrent disease.

Adult↗

PubMed1992

Phyllodes tumor: clinicopathologic review of 60 patients and flow cytometric analysis in 30 patients.

We reviewed 66 phyllodes tumors of the breast from 60 patients. Our patients included 59 women and one man ranging in age from 16 to 72 years. Fifty patients presented for primary treatment of newly diagnosed breast masses, nine presented with recurrent tumors, and one presented with soft tissue metastases 9 years after bilateral subcutaneous mastectomies and multiple chest wall recurrences of phyllodes tumor. After 0.3 to 53.2 years (mean, 15.5 years) of follow-up, 26 (43.3%) patients are free of disease without recurrence, 26 (43.3%) patients are dead of other (17 patients) or unknown (nine patients) causes, four (6.7%) patients had locally recurrent tumor 0.7 to 2.9 years after lumpectomy and are free of disease 3 months to 12 years after re-excision or simple mastectomy, two (3.3%) patients are lost to follow-up, and two (3.3%) patients died with metastatic disease 1.8 and 7 years after diagnosis. Histologic features and flow cytometric analysis showed no correlation with outcome. Fifty-six breast tumors were biphasic and nine were purely stromal tumors. Twenty-six (47%) biphasic tumors showed stromal overgrowth. Tumor margins were pushing in 20 (39%) and infiltrative in 29 (61%) of 49 evaluable cases. Twenty-one tumors were highly cellular and 17 showed cytologic atypia. Necrosis was identified in 16 tumors. Mitotic rates ranged from 0/10 high-power fields to 48/10 high-power fields. Twenty-four diploid, six aneuploid, three tetraploid, and one polyploid tumor were identified by flow cytometry. S-phase fractions tended to be higher in nondiploid tumors. Neither DNA content nor S-phase fraction correlated with outcome. Our results indicate that most mammary phyllodes tumors, including purely stromal tumors, behave as low-grade, nonmetastasizing neoplasms. Neither histologic evaluation nor DNA content provides reliable clues concerning the natural history of an individual tumor.

Adolescent↗

PubMed1978

Temporal changes in histone acetylation.

The incorporation of tritiated acetate was studied in developing and aging rats. Thymus, liver and serum were collected 30 minutes after injection of acetate. The trichloroacetic acid precipitable histone fraction was then extracted from liver and thymus and its radioactivity determined. Serum and cytoplasmic fractions were also counted. Serum activity declined with age. Thymus histone and cytoplasmic fractions showed a cyclic pattern. Acetylation of liver histones showed a straight line decline to a relatively constant level. The decline in acetylation of liver histones is postulated to be due to repression of acetylation processes and is thought to parallel the change of hepatocytes from a diploid to a polyploid state.

Acetates↗

PubMed1991

Effect of dietary restriction and aging on polyploidy in rat liver.

Liver polyploidy levels were compared as a function of age and diet in male Fischer 344 rats between 1 and 24 months of age. Dietary restriction was imposed on one group by reducing their food intake to 60% of ad libitum food intake. Histological sections of the livers of animals at each age and diet were examined. Diploid, tetraploid and octaploid nuclei were observed, and their size and frequency established. There were no differences in the diameter or volume of these size classes as a function of age or diet. An age-related decline in the percentage of diploid nuclei, coupled with an increase in the percentage of tetraploid and octaploid nuclei was observed in both groups. The major difference between the two groups was that the adult level of liver polyploidy was attained more slowly in the animals on dietary restriction as compared to the ad libitum fed controls. Polyploid cell formation in the liver is under the control of growth hormone, thyroid hormone and thymus, all of which might be influenced by dietary restriction.

Aging↗

PubMed1985

Immune abnormalities in the diabetic New Zealand obese (NZO) mouse: insulin treatment partially suppresses splenic hyperactivity measured by flow cytometric analysis.

Immune abnormalities in both the humoral and cell-mediated immune systems were found in New Zealand obese (NZO) mice, a model of diabetes associated with autoimmune disease. Both the formation of anti-sheep red blood cell plaques and mitogen stimulation of NZO spleen cells were significantly decreased compared to normal strains of mice. In addition to perturbations of splenic lymphocyte function, the enlarged spleens of NZO mice demonstrated increased cycling cells as measured by flow cytometric analysis of the DNA content of individual cells. These abnormalities are similar but less pronounced than those found in another autoimmune model, the New Zealand black (NZB) strain. The pancreases of diabetic NZO mice contained a higher fraction of nuclei with greater than 2c amount of DNA. Chronic insulin administration decreased the percentages of splenic proliferating cells and polyploid pancreas cells in NZO mice. In addition, insulin treatment of NZO mice decreased spleen weights and serum glucose levels. Chronic insulin treatment did not alter these parameters in either nondiabetic Balb/c or autoimmune NZB mice. Thus, the features of the NZO strain which serve as both an autoimmunity model and a diabetes model can be dissociated. Insulin treatment had a unique effect on NZO traits but not on NZB traits even through many of these traits were present in both strains. In conclusion, although autoimmunity may underlie the diseases of both the NZO and the NZB strains, the amelioration of some of the features of the NZO strain by insulin may represent the beneficial effects of insulin on the metabolic control of cellular function in NZO mice.

Animals↗

PubMed1992

The effects of cisplatin on murine metaphase II oocytes.

This study was undertaken to determine if cisplatin can induce aneuploidy in murine oocytes treated prior to ovulation. Control animals were injected with intraperitoneal (ip) saline and the treatment animals were divided into three different dose schedules for ip cisplatin. After ovulation induction, the oocytes were processed for cytogenetic analysis and the chromosomes were counted. There were significantly less oocytes ovulated in the treatment groups when compared to control animals. There was a significant increase in hypohaploid cells counted in the 7.5 mg/kg treatment group, but the percentages of hyperhaploid and polyploid cells were not increased in the treatment groups. The cytogenetic effects of cisplatin in vivo and in vitro are reviewed.

Aneuploidy↗

PubMed1992

Flow-cytometric DNA analysis of stages IB and IIA cervical carcinoma.

The prognostic significance of flow-cytometric DNA analysis was assessed in 375 stages IB and IIA squamous cell carcinoma patients treated with radical hysterectomy and lymphadenectomy at the Mayo Clinic between 1956 and 1985. Paraffin-embedded samples containing at least 20% tumor were dewaxed, rehydrated, stained with propidium iodide, and analyzed. Among 344 assessable samples, 136 (40%) were diploid and 208 (60%) were nondiploid (26 tetraploid, 158 aneuploid, and 24 polyploid). Diploid cases were further subclassified: 25 high proliferative phase (HPP) (S+G2M greater than 20%) and 111 low proliferative phase. No significant correlation was noted between DNA diploid patterns and stage, tumor size, grade, or histotype, but HPP diploid tumors had a significantly higher risk of nodal metastasis. With a mean follow-up period of 150 months, 62 patients died of disease. No significant difference was observed in survival rates (SR) between diploid and nondiploid tumors, but the subset of HPP diploid tumors had a prognosis significantly worse than that of any other group (P less than 0.01). Other significant variables included nodal metastases, parametrial extension, age, and clinical stage. While ploidy patterns did not assign additional risk to node-positive lesions, HPP diploid tumors in node-negative patients were associated with a significantly lower SR. Multivariate analyses in node-negative patients demonstrated that stage, histologic subtype, and HPP diploid patterns retained prognostic independence.

Carcinoma, Squamous Cell↗

PubMed1977

The genome-associated, specific RNA binding proteins of avian and mammalian type C viruses.

A structural protein purified from the Rous sarcoma virus (RSV) can specificially bind in vitro to purified avian, but not mammalian, type C viral RNA. Following ultraviolet irradiation of viral particles under conditions which stabilize the polyploid 70S viral RNA, the same polypeptide can be directly purified from the RSV genome. Based on its electrophoretic mobility in polyacrylamide gels containing sodium dodecylsulfate, the RNA binding protein has been identified as the major phosphoprotein (p19) of avian type C viruses. Similar experiments show that the major phosphoproteins of mammalian type C viruses (p12 for murine viruses and p16 for endogenous primate viruses) are also the specific RNA binding proteins and, similarly, are found closely associated with the 70S RNA genomes in the intact viral particles.

Avian Sarcoma Viruses↗

PubMed1990

The fission yeast cut1+ gene regulates spindle pole body duplication and has homology to the budding yeast ESP1 gene.

Mutations in the fission yeast cut1+, cut2+, and cut10+ genes uncouple normally coordinated mitotic events and deregulate, rather than arrest, mitosis. DNA synthesis continues, making polyploid nuclei with several spindles. Multiple, aberrant spindle pole bodies (SPBs) are produced in cut1 mutant cells. The cut1+ and cut2+ genes are cloned by transformation. High gene dosage of cut1+ also complements cut2 and cut10 mutants. The cut2+ gene, however, complements only cut2. The 210 kd cut1+ gene product contains putative ATP binding and helical coil regions followed by a COOH-terminal domain homologous to the S. cerevisiae gene ESP1. Mutations in the ESP1 gene also result in many SPBs. The cut1+ product is shown by anti-cut1 antibody to be a rare component of the insoluble nuclear fraction. It may play a key role in coupling chromosome disjunction with other cell cycle events and is potentially a component, regulator, or motor for the SPB and/or kinetochores.

Amino Acid Sequence↗

PubMed1991

The Drosophila plutonium and pan gu genes regulate entry into S phase at fertilization.

Mutations in the Drosophila maternal genes plutonium (plu) and pan gu (png) have the striking phenotype that DNA replication initiates in unfertilized eggs. Fertilized eggs from plu or png mutant mothers also have a mutant phenotype; DNA replication is uncoupled from nuclear division, resulting in giant, polyploid nuclei. Analysis of multiple alleles of these genes indicates that their wild-type function is required to maintain repression of DNA replication until fertilization. The phenotype of two png alleles suggests that this gene also may play a direct role in coupling S phase and mitosis during the early cleavage divisions. We describe genetic interactions among png, plu, and the previously identified gene gnu that demonstrate these three genes regulate the same process.

Alleles↗

PubMed1991

Requirement for phosphorylation and localization of the Bicaudal-D protein in Drosophila oocyte differentiation.

In the Drosophila female the product of the germline stem cell, the cystoblast, gives rise to 16 interconnected cystocytes. One of them differentiates into the oocyte, while the 15 others become polyploid nurse cells. Bic-D is required for the differentiation of an oocyte and hence for fertility. Recessive mutations in Bic-D block the oocyte-specific accumulation of its own and other RNAs. Based on its properties and distribution, the Bic-D protein appears to be a component of a cytoskeletal transport or anchoring system. Additional results suggest that the phosphorylation of the Bic-D protein is essential for its accumulation in the pro-oocyte and that this process leads to the gradual localization to the pro-oocyte of factors required for oocyte differentiation.

Alleles↗

PubMed1992

chickadee encodes a profilin required for intercellular cytoplasm transport during Drosophila oogenesis.

The entire cytoplasmic contents of 15 highly polyploid nurse cells are transported rapidly to the oocyte near the end of Drosophila oogenesis. chickadee is one of a small group of genes whose mutant phenotype includes a disruption of this nurse cell cytoplasm transport. We have cloned the chickadee gene and found that cDNA clones encode a protein 40% identical to yeast and Acanthamoeba profilin. The nurse cells from chickadee egg chambers that lack ovary-specific profilin fail to synthesize cytoplasmic actin networks correctly. In addition, the nurse cell nuclei in chickadee egg chambers become displaced and often partially stretched through the channels leading into the oocyte, blocking the flow of cytoplasm. We suggest that the newly synthesized cytoplasmic actin networks are responsible for maintaining nuclear position in the nurse cells.

Amino Acid Sequence↗

PubMed1989

Electrofusion parameters for mouse two-cell embryos.

We studied electrofusion of mouse two-cell embryos in order to define parameters which would result in a high yield of fused embryos. Various cell alignment times (from <10 to >60 s) and alternating current percentages (2 to 100%) were examined. The fusion parameters tested were the number of fusion pulses (1-9), pulse length (30-90 mus) and pulse strength (0.50-1.79 kV/cm). Furthermore different combinations of these three parameters were tested. In addition the influence of several embryo culture media on the fusion rates was examined. The results show that the fusion rate of the embryos increases with shorter alignment and higher percentages of the alternating current. The highest fusion rate (95%) was obtained by use of one pulse with a duration of 70 mus and a field strength of 0.60-0.79 kV/cm. The survival rate of the embryos was best if Whitten Medium was used before and after the fusion pulses. The fusion of two-cell stages results in tetraploid embryos which can serve as models for studies in polyploid cells.

Journal Article↗

PubMed1990

Cell number and incidence of chromosomal anomalies in bovine blastocysts fertilized in vitro followed by culture in vitro or in vivo in rabbit oviducts.

The total number of cells and the incidence of chromosomal anomalies in bovine blastocysts cultured in vitro or in vivo in rabbit oviducts were investigated from the four-cell stage after in-vitro fertilization of in-vitro matured follicular oocytes. The total number of cells (80 vs 179) in the oviduct-cultured blastocysts was nearly double that (43 vs 80) of blastocysts cultured in vitro at early and expanded blastocyst stages. In both culture systems, the total number of cells increased with the stage of development. Mitotic index (number of metaphase plates/total number of cells) of blastocysts decreased with development from early (11.5 vs 13.8%) to hatched blastocyst stages (4.8 vs 2.8%) in in-vitro and in-vivo culture systems, respectively. Overall, chromosomal anomalies were observed in 37.5% (27 27 ) of embryos cultured in vitro and in 28.0% (7 24 ) cultured in vivo, respectively. Incidence of chromosomal anomalies did not depend on such factors as culture system or stage of development. Most chromosomal anomalies were polyploid and mixoploid cells.

Journal Article↗

PubMed1993

Genetic transformation of industrial yeasts using an amino acid analog resistance gene as a directly selectable marker.

Prototrophic and often polyploid yeasts of industrial use require some dominant genes as directly selective markers for the transformation. We examined the applicability of a dominant gene, ARO4-OFP, which causes the resistance to PFP plus tyrosine, to direct selection of the transformants from 2 laboratory and 6 industrial strains, including bakers', distillers', winery, and saké yeasts. Although the transformation rates were low and seemed different among strains, the ARO4-OFP gene was applicable to all strains tested for direct selection of the transformants.

Biotechnology↗

PubMed1989

Cytogenetic studies on the adult T-cell leukemia in Japan.

Cytogenetic studies were performed on 16 patients with ATL seen in Northern Kyushu island; nine were patients with acute type leukemia, one with crisis type and five with lymphoma type. The serum antibody for HTLV-1 (ATLA) was positive in all patients and the phenotype of ATL cells were ERFC+, OKT3+, OKT4+, OKT6-, OKT8-, OKT10+, OKla1+/- and Tac+. Abnormal findings of chromosomes were observed in 15 patients. Thirteen patients were in near diploid range. One patient was in triploid range and one patient was in tetraploid range. The polyploid karyotypes were found only in lymphoma type patients. Trisomy 3 and trisomy 7 were observed each in three patients with acute type of ATL. The most frequent abnormal rearrangement was observed in the long arm of chromosome 6 and the break occurred at band 6q15 and 6q21 each in four patients in this series.

Acute Disease↗

PubMed1988

Griseofulvin.

Griseofulvin (GF) is a mycotoxin produced by various species of Penicillium including P. griseofulvum Dierckx, P. janczewski (P. nigricans) and P. patulum. It is active against dermatophytic fungi of different species in the genera Microsporum, Trychophyton and Epidermophyton. Because of its capacity to concentrate in the keratinous layer of the epidermis and its relatively low toxicity in man, it has been extensively used in the therapy of dermatophytoses by oral administration. The biological activity of GF towards fungi is manifested as nuclear and mitotic abnormalities followed by distortions in the hyphal morphology. Mitotic segregation is also induced in fungi by GF treatment. In higher eukaryotes the cytostatic action of GF is essentially due to a mitotic arrest at late metaphase/early anaphase. The cytological effects observable both in vivo and in vitro on different plant and animal cell systems, include C-mitoses, multipolar mitoses and multinuclearity. Prolonged GF treatment in experimental animals provokes biochemical changes consisting mainly of disturbances of porphyrin metabolism, variation in the microsomal cytochrome levels and formation of Mallory bodies. In mice these alterations are followed by the development of multiple hepatomas. Evidence of tumor induction by GF has been obtained in mice and rats, but not in hamsters. GF may also act either as a promoting or a co-carcinogenic agent, depending on the circumstances of its administration. It has been found to increase the frequency of cell transformation induced by polyoma virus, but not to induce cell transformation per se. Induction of sperm abnormalities has been observed in GF-treated mice. The embryotoxic and teratogenic action of GF has been demonstrated in pregnant rats exposed during organogenesis. Genetic effects of GF have been investigated by the following tests: Salmonella/microsome mutagenicity assay, point mutations in mammalian and plant cells, DNA damage and repair, SCE, chromosome aberrations, micronuclei, dominant lethals, aneuploidy in lower and higher eukaryotes. A positive response has been obtained in the assays on numerical chromosome changes in all the systems analyzed; limited or inconclusive evidence has been obtained for SCE and structural chromosome changes. Doubled or highly polyploid sets can be detected in all types of cells during or immediately after GF treatment. A marked increase in chromosome number variation is observed at various times after withdrawal of the drug, with prevailing hyperdiploid and reduced sets in animal cells and plant cells respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Carcinogens↗