SEARCH · PubMed Health

Results for “diploidization”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 757 records · Page 42Linked to original sources

PubMed1989

Protective effect of glutathione against oxygen-induced growth inhibition of human diploid fibroblasts.

The reduced glutathione level in human diploid fibroblasts was increased by the addition of N-acetylcysteine or reduced glutathione ethylester into the culture medium, while it was decreased by the addition of L-buthionine-(R,S)-sulfoximine or diethyl maleate. The hyperbaric oxygen-induced reduction in colony-forming ability was prevented in the N-acetylcysteine- or reduced glutathione ethylester-treated cells, and enhanced in the L-buthionine-(R,S)-sulfoximine- or diethyl maleate-treated cells. The extent of the growth inhibition is well correlated with the cellular glutathione level. It is deduced that glutathione is an important safeguard against the oxygen-induced growth inhibition of human diploid cells.

Buthionine Sulfoximine↗

PubMed1987

The growth of polio virus in human diploid fibroblasts grown with cellulose microcarriers in suspension cultures.

Human diploid fibroblasts have been successfully grown with cellulose fiber microcarriers in suspension giving values of between 1 to 2 X 10(6) cells/ml. When infected with polio virus type 1 titers were obtained which were at least as good or better than those obtained with monkey kidney cells and similar to that obtained with Vero cells. Good results were also obtained using conventional microcarriers such as Cytodex, Biosilon and Gelibeads. Our results suggest that many of the technical difficulties in growing human diploid fibroblasts on microcarriers can be overcome allowing these cells to be a favourable alternative to heteroploid cells as a substrate for viral vaccine production.

Biotechnology↗

PubMedDate not supplied

[Relation of the radiosensitivity of yeast cells to the LET of the radiation. Effect of additional growth and its contribution to resistance and the shape of the survival curve of diploid cells].

A study was made of the contribution of the additional growth effect to the survival rate of Saccharomyces cerevisiae diploid yeasts and its influence on the survival curve shape after exposure to ionizing radiation of different linear energy transfer (LET). The effect of the additional growth was shown to be the only factor responsible for a sigmoid shape of the survival curve of diploid yeasts affected by high LET radiation. As LET increased the contribution of the additional growth effect to the survival rate decreased: this was due to the pattern of cell distribution by the number of radiation lesions that altered with alterations in LET.

Carbon↗

PubMed1988

[Mutability of LYS2 gene in diploid Saccharomyces yeasts. II. Frequency of mutants induced by 6-N-hydroxylaminopurine and propiolactone].

Chemical mutagens 6-N-hydroxylaminopurine (HAP) and propiolactone (PRO) induce Lys2 mutants with high frequency in diploid yeast Saccharomyces cerevisiae. HAP induces such mutants even in tetraploid strains. The genetic analysis of mutants was performed. It is shown that PRO induces mutants by means of "mutation-mitotic segregation" mechanism, while HAP induces mutants through novel mechanism "both allele mutation". Manifestation of such mechanism is the null fertility after meiosis of diploid mutants induced by HAP.

Adenine↗

PubMed1979

The T-lymphocyte as a diploid reference standard for flow cytometry.

T-lymphocytes prepared from the peripheral blood of normal individuals exhibit uniform postmitotic DNA contents that are constant from individual to individual when fixed in ethanol and stained with mithramycin, or when fixed in formalin and stained with acriflavine-Feulgen and analyzed by flow microfluorometry. T-lymphocytes fixed by either method are stable on storage for several months. These cells are suitable for use as an external diploid reference standard for flow cytometric detection of cells with abnormalities in postmitotic content exceeding 5% of diploid reference. Cells with abnormalities in postmitotic DNA content of less than 5% can be detected in mixtures containing both normal and malignant cells by multiparameter analysis.

DNA↗

PubMed1988

[Determination of the antiproliferative activity of human recombinant interferon (reaferon) on diploid human cells].

Dependence of the antiproliferative activity of reaferon in cultures of human diploid cells on the drug dose and duration of its action on the cells was studied by counting viable cells in the Goriaev chamber. No relationship was detected. However, such dependence was clearly evident with using tumor cells. With counting of mitoses it was shown that in doses of 10(4) and 10(3) IU reaferon significantly inhibited the cell mitotic activity when the mitotic index in the control of the strain M-19 cells exceeded 25%. When the mitotic index was lower than 25% reaferon in all the doses had no inhibitory effect on the cells. On the contrary it was noted that there was even a certain tendency to stimulation of the mitotic activity. Therefore, the line of the human diploid fibroblast cells (strain M-19) may be used for assay of reaferon antiproliferative activity in case of high mitotic activity in its monolayer (the mitotic index higher than 25%). It was also demonstrated that the dose of reaferon should be not lower than 1000 IU per 1 ml of the medium.

Cell Count↗

PubMed1988

High efficiency DNA-mediated transformation of human diploid fibroblasts.

Normal human diploid fibroblasts (HDF) have only rarely been used as recipients in DNA transfection experiments even though they have the potential to add to our knowledge about the genes that control normal cell proliferation. A major impediment to the use of HDF has been their poor transfection frequency. In this paper, we show that IMR-90 human diploid fibroblasts can be stably transfected at high efficiency with pRSVneo at an average frequency of 2 x 10(-3) (0.2%) using a modified calcium phosphate-DNA coprecipitation transfection protocol. Prior to this report, the best transfection frequencies of HDF were on the order of 10(-5)-10(-4). In the present protocol it is very important to maintain relatively low cell densities, particularly during the selection process post-transfection. Using this protocol other neo-containing plasmids also yield high transfection frequencies in IMR-90. IMR-90, which are readily available from the NIH Aging Cell Repository, may be one of the best HDF to use as recipients because they are five times as efficient as are WI-38, which is another well characterized HDF.

Calcium Phosphates↗

PubMed1987

[Different effects of selenium on proliferation of human lung adenocarcinoma cells and human embryonic lung diploid cells in vitro].

After treating human lung adenocarcinoma cells by Na2SeO3 (1 microgram/ml) for 24 hours, its mitotic index decreased by 50%. The reduction rate was directly proportional to selenite concentration (1-5 micrograms/ml). In the meantime, the labelling index, growth rate and progression of the cell cycle were also inhibited. In contrast to the above observation, there was no marked change in the cell count, mitotic index, labelling index and the average silver granule number in the human embryonic lung diploid cells treated by Na2SeO3 (1-5 micrograms/ml) for 1-3 days. When human embryonic lung diploid cells were mix-cultured with human lung adenocarcinoma cells in the presence of 5 micrograms/ml Na2SeO3 for 24 hours, the former maintained a normal morphology, while the lung cancer cells showed heavily vacuolated cytoplasms and distorted nuclei.

Adenocarcinoma↗

PubMed1978

Diploid formation of Candida tropicalis via protoplast fusion.

Haploid auxotrophic mutants were produced from Candida tropicalis, and protoplast usion was induced by polyethylene glycol. The resulting nutritional complementation was due to heterokaryon formation and, at a much lower frequenty, to spontaneous diploidization. During cultivation, heterokaryotic clones regularly gave rise to heterozygous diploids from which, in turn, haploids could be isolated. The technique of protoplast fusion gives an opportunity for genetic analysis of this and similarly asexual fungal species.

Candida↗

PubMed1987

Induction of anchorage independence in human diploid foreskin fibroblasts by carcinogenic metal salts.

We studied whether arsenic, nickel, and chromium compounds that are human carcinogens could induce transformation of cultured primary human diploid foreskin cells (HFC). All nickel compounds tested, PbCrO4, K2Cr2O7, CrO3, Na2HAsO4, NaAsO2, and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) caused significant (p = 0.001) dose-dependent inductions of anchorage-independent colonies in HFC. KH2AsO4, CaCl2, MnCl2, and Hg(CH3CO2)2 did not induce anchorage independence. Optimal expression times for induction of anchorage independence in HFC were observed as early as 11 days following treatment with MNNG, Ni3S2, Ni(C2H3O2), or NiSO4. Cell strains derived from anchorage-independent colonies showed 33 to 429-fold higher plating efficiencies in soft agar than parental populations, and the anchorage-independent phenotype was stable for eight passages, at which time cells senesced. Anchorage-independent cell strains derived from metal salt-treated cells were not resistant to the cytotoxicity of metal salts, indicating metal salts induced rather than selected for anchorage independence. Nine of 10 cell strains derived from metal compound- or MNNG-induced anchorage-independent colonies displayed the same or lower saturation densities than untreated human fibroblasts. None of these cell strains escaped senescence or showed definitive morphological transformation. MNNG (1 micrograms/ml) induced anchorage independence and mutation to ouabain resistance and 6-thioguanine resistance in HFC, but concentrations of Ni2S3 that induced anchorage independence did not induce mutation at either locus in HFC. These results demonstrate that carcinogenic metal salts induce stable anchorage independence early in human diploid foreskin fibroblasts, and this anchorage independence is independent of other in vitro markers of fibroblast transformation, such as focus formation or immortality. Metal salt induction of anchorage independence can now be used as an assay to study mechanisms of genotoxicity exerted by carcinogenic metal compounds in human cells.

Acetates↗

PubMed1987

Antibody response after a two-year intradermal booster of rabies human diploid cell vaccine.

A study was undertaken to evaluate the effectiveness of a low dose of rabies human diploid cell vaccine administered intradermally for preexposure booster inoculation. Seventy-six volunteers received a 0.1-ml dose of rabies human diploid cell vaccine intradermally, approximately 2 years after their primary series. Though only 25 (32.9%) had a titer less than 0.5 IU/ml before the booster, all had a postbooster titer of greater than or equal to 4.0 IU/ml 3 weeks later. Five of 73 (6.8%) reported an allergic reaction after the booster.

Adolescent↗

PubMedDate not supplied

[Preparation and characteristics of diploid cell strains from the tissues of a bovine embryo].

Two strains of diploid cells were prepared from the lung (BEL-2) and skin-muscle (SMBE-3) tissues of a bovine embryo. According to the results of morphological and karyological studies, these cultures consisted of fibroblast-like cells retaining diploid chromosome number (60) in the process of long-term cultivation. These cell populations have a limited life span (75-80 passages) and 3 growth phases. The species appurtenance of BEL-2 and SMBE-3 cells was confirmed. The cells were not contaminated with mycoplasma or extraneous viruses, had no tumorigenic activity. The BEL-2 cell culture is most susceptible to measles virus, SMBE-3 culture to vaccinia virus.

Animals↗

PubMed1979

[Prolongation of the mitotic life span of diploid human glia cells in a quantitative cell culture system by centrophenoxine (author's transl)].

The accumulation of lipofuscin in postmitotic and reversible postmitotic cells of animals and man is an age correlated process. The mechanism of the lipofuscin accumulation and the function of lipofuscin in the aging cell is not fully understood. The accumulation of lipofuscin in vivo and in vitro can be slowed down by the action of centrophenoxine (Helfergin). Diploid cells are the only reversible postmitotic cells of man that have a genetically determined limited cell division capacity and accumulate lipofuscin in the process of the cellular aging in a quantitative cell culture system in vitro. The treatment of diploid human glia cells with centrophenoxine results in increasing the cell division capacity by 30--40% in vitro. The data demonstrate that the centrophenoxine induced inhibition of lipofuscin accumulation has a positive influence on the cell metabolism and the mitotic division capacity and causes a delay of the cellular aging of the human glia cells in vitro.

Cells, Cultured↗

PubMed1978

Clinical trial with an anti-rabies human diploid cell vaccine (HDCV).

A clinical trial with an anti-rabies human diploid cell vaccine (HDCV) Mérieux, has been carried out by the Government Central Laboratories and the District Health Office, Ministry of Health, Jerusalem, Israel, on 25 persons bitten by stray dogs and cats. These bitten persons were given 6 injections of the above-mentioned vaccine on days 0, 3, 7, 14, 30 and 90 post-exposure. A through medical examination was carried out by a qualified physician in order to establish the local and systemic side effects. These side effects were trivial and were mostly observed with the third and fourth injections. In addition a neutralization test on mice was carried out with all sera taken on the days of injection. There was a prompt and adequate development of neutralizing antibodies even on the seventh day after the beginning of treatment, and before the fourth injection. In several cases there was a very high level of neutralizing antibodies even reaching as much as 500 I.U./ml. In conclusion these results have shown that the diploid cell vaccine is a very safe immunogenic vaccine and the authors recommend its use for pre- and post-exposure.

Animals↗

PubMed1987

A growth inhibitory protein secreted by human diploid fibroblasts. Partial purification and characterization.

We have identified and partially purified a growth inhibitor protein secreted by human diploid fibroblast cells. This protein is not secreted constitutively but only after induction with the double stranded hetero duplex polyriboinosinic:polyribocytidylic acid. The growth inhibitory activity has been purified 3,800-fold and has an estimated molecular mass of 12,000 daltons. The protein will inhibit the growth in culture of human diploid fibroblast cells, human cells derived from tumors, and mouse L cells. Although interferon-beta is secreted with the growth inhibitory protein, the partially purified growth inhibitory protein has no antiviral activity, and its activity is not neutralized by antibodies to interferon-alpha, interferon-beta, and interferon-gamma. We believe this growth inhibitory activity to reside in a newly defined protein and have named it fibroblast-derived growth inhibitor.

Cycloheximide↗

PubMed1985

[Comparative characteristics of protein-synthesizing apparatus of diploid and aneuploid human embryo fibroblasts].

The time of average polypeptide chain synthesis (tc), distribution of synthesized polypeptides according to their molecular masses, the ratio of translating and nontranslating ribosomes and polyribosomes of different size have been analyzed for diploid and aneuploid strains of fibroblasts. The magnitude of tc as well as the size of polypeptide chains synthesized were found to be similar for both kinds of fibroblasts. The relative cellular content of the translating ribosomes has been shown to decrease during the transition of cells from both strains to the stationary growth phase. The relative content of heavy polyribosomes is lower in aneuploid cells as compared with that in diploid cells. The process of translation in aneuploid fibroblasts is concluded to have no essential deviations from normal.

Aneuploidy↗

PubMed1985

Mechanisms of human cell neoplastic transformation: X-ray-induced abnormal clone formation in long-term cultures of human diploid fibroblasts.

Early passage cultures of a strain of normal human diploid fibroblasts were exposed to various doses of X-rays. The cells were serially passaged and followed throughout their life span in vitro. G-banded metaphase chromosome preparations were examined at each subculture to determine the presence of abnormal clones, i.e., groups of cells bearing identical chromosomal rearrangements. It was found that X-irradiation induced random chromosomal rearrangements which persisted throughout the life span of the cells. No abnormal clones were observed among the progeny of four nonirradiated cultures, nor in seven of nine cultures exposed to single radiation doses. On the other hand, multiple abnormal clones emerged among the progeny of cells in all five cultures exposed to multiple sequential radiation doses (three doses of 400 or 600 rads each). Evidence of clonal expansion and attenuation and of clonal succession during serial passaging occurred in these populations. In several cases, these clones expanded to include most of the cell population before the cultures became senescent. These findings are discussed in terms of their possible role in the transformation of human diploid cells by radiation.

Cell Transformation, Neoplastic↗

PubMed1977

Cell kinetics of mouse urinary bladder epithelium. IV. Changes in cell proliferation, nuclear DNA content, and number of diploid, tetraploid and octoploid cells after a single dose of dibutylnitrosamine.

The initial effect of a single subcutaneous injection of 0.01 ml of dibutylnitrosamine on the mouse (hr/hr strain) urinary bladder epithelium was a block in DNA synthesis in the diploid cells followed by a regenerative reaction. This did not, however, lead to a subsequent wave of increased DNA synthesis among the tetraploid cells. Later, a new wave of DNA synthesis occurred among the diploid cells, and again there was no subsequent wave of tetraploid DNA synthesis. The total cell number was not affected. These disturbances resulted in periods of reduced numbers of octoploid cells. This effect was unlike that obtained in previously published experiments using cyclophosphamide, which led to considerable hyperplasia, especially of octoploid cells, and no disturbance of tetraploid DNA synthesis. Thus the action of a single dose of dibutylnitrosamine on the epithelial cells in the mouse urinary bladder is very different from that of cyclophosphamide in a single dose, but it is not possible to say whether this has anything to do with the carcinogenicity of the nitrosamine.

Animals↗