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At least 217 records · Page 12Linked to original sources
PubMed1992

Ultrastructure and biosynthetic activity of polyploid atrial myocytes in patients with mitral valve disease.

Biopsies of right auricle of human heart have been obtained during open heart surgery from 6 patients aged 23 to 49. The DNA and total protein content have been determined in isolated myocytes by two-wavelength scanning cytophotometry after double staining: Feulgen and naphthol yellow S. In all the biopsies predominant are polyploid hypertrophied myocytes. Both hypertrophied non-degenerating cells and cells with different extent of degenerative changes, primarily of myofibrils and membranes, are present. The highest extent of cell ploidy is in patients belonging to functional class IV according to the classification of New York Heart Association (NYHA); in these cases 72 to 98% of cells have nuclei with 8 c and more DNA content. With an increase in ploidy level, cells grow in size and in protein content, however the rate of this growth is much lower than that of DNA content in cells. There is no direct relation between ploidy and cell degeneration extent and no inverse relation between degeneration extent and ejection fraction.

Adult↗
PubMed1991

DNA-cytometric detection of euploid polyploidization in oral lichen ruber planus.

The DNA distribution was analyzed in 29 cases of oral lichen ruber planus that were negative for human papillomavirus and not suspected of being precancerous. Monolayer smears prepared from formalin-fixed, paraffin-embedded tissues were automatically Feulgen stained and used for rapid interactive DNA cytometry via a TV-based image analysis system combined with an automated microscope. Nuclei with DNA contents greater than 4c were found in 25 cases (86%). DNA contents greater than 8c were seen in five cases (17%), and small peaks at 8c were found in three cases. These increased DNA values in nonprecancerous lesions must be interpreted as euploid polyploidization and have to be taken into account if DNA measurements are performed for diagnostic purposes in lichen ruber planus lesions that are suspected of having malignant transformation.

DNA↗
PubMed1991

[Nuclear DNA contents in the cells of squamous cell carcinoma. III. Separation and analysis of polyploid cells].

In order to reveal the cytological nature of polyploid cells, the cell suspension of squamous cell carcinoma was separated into low density (1.050 greater than), intermediate density (1.050 to 1.088), and high density (1.988 greater than) fractions, by density gradient centrifugation. The DNA content of the tumor cells in each fraction were measured on the smear specimens prepared by Giemsa's staining and Feulgen's stainings. As the results, it was found that the cells showing high NC ratio and having high DNA content were observed in the high density fraction. However, there was no specific relationship between the nuclear contour index and density of the tumor cell.

Aged↗
PubMed1990

[N-terminal sequence of omega-gliadins from Aegilops longissima. The origin of the genome of polyploid wheat].

Using high-performance reversed phase liquid chromatography, the major components of omega-gliadins were isolated from four samples of Aegilops longissima. A high interspecific variability of Ae. longissima with regard to gliadin composition was demonstrated. The N-terminal sequences of omega-gliadins were determined. It was shown that omega-gliadins under study belong to the SRQ type earlier discovered in hexaploid wheat species and in Ae. squarrosa. It is supposed that this type of sequence is specific to the whole Aegilops genus. The N-terminal sequence of omega-gliadin of Ae. longissima was identified and its similarity to the alpha/beta-type sequence found in hexaploid wheat species was revealed. The data obtained are discussed in terms of the origin of polyploid wheat genomes.

Amino Acid Sequence↗
PubMed1987

[Polyploidization dynamics of tertiary trophoblast giant cells in the rat placenta].

Polyploidization peculiarities of tertiary giant trophoblast cells during their active detaching from the ectoplacental cone and migrating into decidua basalis are investigated. On the 12th day of gestation, the ploidy of the majority of cell nuclei varies within 4-8c, although there are a few 16c and 32c nuclei. On the 13th and 14th days of gestation, the ploidy level of tertiary giant trophoblast cells enhances; 8c and 16c nuclei prevail, the percentage of 32c nuclei increases, 64c nuclei arising. The ploidy level of tertiary giant cell coincides with the average and/or maximum ploidy degree of precursor cell populations. The significance of polyploidy as indispensable condition of differentiation of the trophoblast cells that actively invade into maternal tissues is discussed.

Animals↗
PubMedDate not supplied

[More active synthesis of the polysaccharide, pullulan, by polyploid cultures of Pullularia pullulans].

The polyploid strains of Pullularia pullulans differ from each other and from the haploid strain in the amount of the polysaccharide pullulan liberated into the cultural broth. The highest pullulan synthesizing activity (per unit of the assimilated carbon source and the synthesized biomass) was manifested by the diploid strain of P. pullulans 1125(13) whose cells produced more pullulan (by 75%) within three days of growth than the cells of the haploid culture. The content of pullulan calculated per unit area of the cell surface increased with the level of ploidy: 1.5-1.8 times in the diploid cultures and 3.4 times in the tetraploid culture cf. the parent haploid culture. Apparently, the polyploidy of the P. pullulans culture was accompanied with mutations involved in the synthesis of the extracellular polysaccharide.

Culture Media↗
PubMedDate not supplied

[Polyploidization of rat hepatocytes induced by x-ray radiation at different periods of the cell cycle].

As determined by the yield of polyploid hepatocytes after X-irradiation of rats with a dose of 6 Gy the S-stage of the cell cycle was most radiosensitive; as to the yield of cells with chromosome aberrations the middle of the G1-stage was the most radiosensitive period of the cell cycle. The differences in the radiosensitivity of the cell cycle stages indicated that although primary lesions were similar molecular mechanisms leading to tre final effect were essentially different.

Animals↗
PubMed1979

Polyploidization and hemiploidization induced by PUVA in vivo.

To obtain additional information on the in vivo injury induced by PUVA treatment, primary cultures were initiated from biopsies of the uninvolved skin of 15 PUVA-treated psoriatic patients, and the cells generated were analysed for morphological and chromosomal modifications. Three biopsies were obtained from each patient, the first one before commencing PUVA therapy (control) and the other two during the course of therapy. It was found that PUVA treatment has diverse effects on the mitotic activity, mitotic mechanisms and chromosomes of the cutaneous cells: (1) an inhibition of cell proliferation during the early stages of therapy followed by a reversion to normal proliferation as the PUVA treatments were continued; the production of (2) cells with more than one nucleus, (3) macrocells, (4) cells with micronuclei, (5) polyploid cells, (6) haploid cells, (7) cells with 13 chromosomes denoting a twofold reduction in the normal number of metaphase chromosomes, (8) end-associations of the chromosomes as in the pachytene phase of meiosis (9) diplotene chromosomes, and (10) chromosomal translocations.

Cell Division↗
PubMed1979

[Intranuclear and cytoplasmic annulate lamellae in the polyploid giant cells of the trophoblast].

Intranuclear and cytoplasmic annulate lamellae in polyploid giant cells of the trophoblast have been studied in rat placenta on days 12--17 of development. The annulate lamellae are present in the cytoplasm within a limited time, being visible on day 12 only. These are arranged in bundles near the nucleus to be moving then to the cytoplasm. The end parts of annulate lamellae are broadened to make cisterns of rough endoplasmic reticulum. Unlike the cytoplasmic annulate lamellae, those found within the nucleus are seen in part of the nuclei investigated throughout the whole period examined to look as single structures (not gathered in bundles), they can be branching, separating closed spaces within the nucleus (making local swellings in the loci of branching; the latter having electron dense or transparent vesicles). Association with nuclear chromatin in some regions is a peculiar feature of the intranuclear annulate lamellae. This association is especially obvious at endoprophase in the cycle ofthe polytene nucleus during the somatic conjugation--chromonemes unite in a bundle and condense. Ultrastructural changes of the annulate lamellae is noted throughout the polytene nucleus cycle and during the cell differentiation. It is supposed that in the case of temporary labile chromosome polyteny in the nuclear cycle, which is characteristic of mammalian trophoblasts, annulate lamellae can well compare, in their function, with the synaptonemal complex--these prevent from too tight associations of homologues in the course of somatic conjugation of chromosomes.

Animals↗
PubMed1979

[Plication of the nuclear membrane and its derivatives in the polyploid cell nuclei of the rat trophoblast].

Folding pattern of the nucleus envelope and intranuclear membrane structures in trophoblast giant cells and in trophoblast of the intermediate region of the rat placenta have been studied. Cells of the intermediate region of the placenta demonstrate deep invaginations resulting in the appearance of lobulated nuclei. Invaginations of the nuclear envelope pass on a narrow fold made by an inner nuclear membrane. The polyploid nuclei of trophoblast giant cells have superficial folds and deeper finger-like invaginations in their envelopes. Such folding trophoblast nuclei in two populations examined are met throughout the whole ontogenesis of the cell. In the giant cells, individual intranuclear tubes or their accumulations are seen. The tubes are made by a unit membrane and are surrounded with a matrix. The nuclear chromatin, diffuse or condenced, is in association with the tube surface. The tubes are met near the nucleolus and on its surface, where these are surrounded with the granular component of the nucleolus. In the trophoblast of the intermediate region of the placenta, intranuclear concentric membranes have been found; made of paired membranes, intramembranous space being filled with electron dense matrix. The concentric membranes lie separately in the karyoplasm, not being associated with the chromatin.

Animals↗
PubMed1978

[Effect of experimental arrest of eye growth on the proliferation and polyploidization of the retinal pigment epithelium in rats].

Following the lens removal from the left eye of the newborn rats, animals were obtained with one normal (control) and another microphtalmic eye. The animals were sacrificed on the 2nd, 3rd, 5th, 7th and 9th days of postnatal development after four injections of 3H-thymidine during 19 hrs. The number of labelled nuclei and mono- and binuclear cells in the central zone of the eye fundus was counted on the autographs. After the initial increase of the index of labelled nuclei in the operated eyes (on the 2nd, 3rd and 5th days) it fell below the control level (on the 7th and 9th days). The number of binuclear cells in the operated eyes, as well as in the control, attains on the 5th day 50% of the total number of cells and remains at this level up to the end of the experiment, whereas in the control eyes the number of binuclear cells increases up to 60% on the 7th and 80% on the 9th day. The results obtained have shown that in rats the factors of total eye growth participate in the control of proliferative activity and polyploidization of the pigment epithelium cells in the retina.

Age Factors↗
PubMed1984

Polyploid cells in ageing hamster fibroblasts in vitro: possible implication of the centrosome.

Fibroblasts from hamster embryos cultivated in vitro present the typical ageing process of other fibroblastic lines, but they also suddenly give rise to giant non dividing cells which could be considered to represent terminally differentiated cells [36]. We investigated the latter mechanism, first by showing that microtubules in these cells depolymerized from the centrosome and not from the cell periphery as in other cells; secondly we analysed the structure of the centrosome on serial sections and found a diminished pericentriolar material; finally time lapse sequence studies of cell division confirmed that this process sometimes aborts giving rise to these giant polyploid cells. As a consequence, what first appeared as a differentiation process is in fact the result of an environmental deterioration which probably reaches a critical level thus creating a catastrophic consequence for the cell.

Animals↗
PubMed1982

[Formation of aberrant polyploid hepatocytes in exposure to the alkylating preparation dipin and to stimulation of proliferation].

One month after the treatment of mice with the alkylating drug Dipin followed by partial hepatectomy 4.7--35.1% of hepatocytes with micronuclei and nuclear bridges in liver were registered. The ploidy level sharply increased. Aberrant cells were the most polyploid ones (16c, 32c). The DNA-fuchsin content in these aberrant polypolid cells decreased by 10--15% due to degrading and non-replication of DNA in the micronuclei.

Alkylating Agents↗
PubMedDate not supplied

[Effect of carbon and nitrogen sources on pullulan biosynthesis by polyploid strains of Pullularia pullulans].

The effect of eight carbohydrates and three nitrogen sources on the activity of pullulan accumulation was studied with a haploid strain, a diploid strain and a tetraploid strain of Pullularia pullulans. The rate of pullulan biosynthesis was found to be the highest in media containing glucose, sucrose and maltose. In this case, the activity of the polysaccharide synthesis in the polyploid strains exceeded that in the haploid strain by 21-80% depending on the carbon source in the medium. The pullulan synthesizing activity of the tetraploid strain depended on the nature of these carbohydrates to a lesser extent than in the case of the haploid and diploid strains. The activity of pullulan synthesis was influenced noticeably by the source of nitrogen in the medium. The greatest amounts of pullulan were accumulated by the three strains in a medium with sodium nitrate.

Carbon↗
PubMed1980

Polyploidization of extraembryonic tissues during mouse embryogenesis.

It has recently been shown that visceral yolk-sac endoderm is derived from the primitive endoderm of the 4.5-day mouse blastocyst (Gardner & Papaioannou, 1975; Gardner & Rossant, 1979). During development, primitive endodermal cells acquire nuclei with more than four times the haploid amount of DNA. The finding of metaphases with multiple sets of chromosomes suggests that the diploid precursors of such endodermal giant cells become truly polyploid. Amniotic cells also contain giant nuclei but the mechanism by which these arise is uncertain. The giant-cell transformation therefore appears to be a general feature of mouse extraembryonic development rather than a phenomenon restricted solely to trophoblast. The basis and significance of these findings are discussed in relation to the development of other extraembryonic membranes both of plant and animal origin.

Animals↗
PubMed1981

Some flow cytofluorimetric studies of the nuclear ploidy of mouse hepatocytes. II. Early changes in nuclear ploidy of mouse hepatocytes following carbon tetrachloride administration: evidence for polyploid nuclei arrested in telophase.

Mature mice have a large proportion of their hepatocyte nuclei in polyploid states (tetraploid and octaploid), and this is more prominent in females. We measured nuclear ploidy distribution cytometrically using ethidium bromide-stained hepatocyte nuclei liberated by in situ collagenase perfusion of the liver via the portal vein. After s.c. administration of 0.2 ml carbon tetrachloride the ploidy distributions of 8-month-old female mice changed from a control of 35% 2N, 45% 4N, and 20% 8N to 54% 2N, 45% 4N and 1% 8N at 6 h, and 65% 2N, 35% 4N and 0% 8N at 24 h. By 72 h 92% of the nuclei were diploid. These changes preceded any changes in mitotic index and S-phase index (3H-TdR autoradiographs). Histology confirmed the loss of higher-ploid nuclei but without mitotic figures or selective cell necrosis to account for the observations. Cleaved nuclei were prominent in sections of liver examined 3 h after CCl4 administration and suggested division of polypoid nuclei that had undergone prior segregation of chromatids and had presumably been arrested in telophase.

Animals↗