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Results 451 - 500 of 1480
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Armstrong M J - - 1997
O6-Methylguanine (O6MeG) is important in induction of chromosome aberrations (abs), with the unusual property that new abs are produced in the second cycle after treatment; cells lacking repair by O6-alkylguanine DNA-alkyltransferase (AGT) have more abs at the second division (M2) than at the first (M1). These second-cycle abs are likely ...
Macpherson J S - - 1997
The effect of the novel topoisomerase I inhibitor NU/ICRF 505 (20 microM, approximate IC50 concentration) on the cell cycle was studied by flow cytometry in four Chinese hamster ovary (CHO) cell lines. Postdrug treated cells were incubated with optimal concentrations of cytochalasin B to prevent re-entry of daughter cells into ...
Inocencio N M - - 1997
We addressed the question of whether furin is the endoprotease primarily responsible for processing the human immunodeficiency virus type I (HIV-I) envelope protein gp160 in mammalian cells. The furin-deficient Chinese hamster ovary (CHO)-K1 strain RPE.40 processed gp160 as efficiently as wild-type CHO-K1 cells in vivo. Although furin can process gp160 ...
Fukasawa M - - 1997
Chinese hamster ovary (CHO) K1 cells, typical nonprofessional phagocytes, exhibited intense phagocytosis of latex beads when incubated under serum-free conditions. Under the serum-free conditions, the recognition mechanism of latex beads by cells was investigated. Exogenous heparin and heparan sulfate but not chondroitin sulfate effectively inhibited the binding of latex beads ...
Kawaguchi Y - - 1997
Induction of polyploidy by vitamin B2 (VB2) was investigated in cultured Chinese hamster lung (CHL/IU) cells. We report that VB2 in the form of needle crystals induces polyploidy via the formation of CHL/IU cells with more than one nucleus. The incidence of polyploid cells depended on the amount of needle ...
Galloway S M - - 1997
Different test results have been reported for the same chemicals in two in vitro chromosome aberration test systems, CHL cells tested by a Japanese protocol and CHO cells tested by the US National Toxicology Program [Sofuni et al., Mutat Res 241:173-213,1990]. Here, laboratories in Japan, the US and the UK ...
Podstavková S - - 1997
The aromatic amine 2-aminofluorene (2-AF) was activated by the intact Chlamydomonas reinhardtii cells to a mutagen that exhibited toxic and mutagenic effects comparable to those of the direct-acting mutagen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). There were different responses of the wildtype and repair-deficient strains to the toxic and mutagenic effect of 2-AF. The ...
Lee M W - - 1996
Chinese hamster ovary (CHO) cells express only a trace amount of phosphatidylethanolamine N-methyltransferase (PEMT) activity. CHO cells make their phosphatidylcholine (PC) via the CDP-choline pathway. We investigated whether or not overexpression of PEMT2, an isoform of PEMT, in these cells would down-regulate the activity of the CDP-choline pathway. Transfection of ...
Kaetzel D M DM - - 1996
Pulse-chase analysis of human platelet-derived growth factor (PDGF) B-chain was conducted in stably transfected Chinese hamster ovary cells to determine precisely the kinetics of processing, intracellular trafficking and secretion. Newly synthesized 31 kDa monomers of the B-chain (p31) dimerized rapidly via disulfide bonds to a p54 species (t1/2 < 30 ...
Fukushima K - - 1996
BACKGROUND: We have isolated a series of temperature-sensitive mutants for cell-proliferation from the BHK21 cell line derived from the golden hamster (Nishimoto & Basilico 1978; Nishimoto et al. 1982). Using these mutants as a recipient of DNA-mediated gene transfer, we have been cloning human genes which complement these ts mutants. ...
Belley A - - 1996
BACKGROUND & AIMS: Colonic mucins secreted by goblet cells protect the colon by preventing the attachment of enteric pathogens to the epithelium. Entamoeba histolytica overcomes this protective barrier and causes ulcerations, allowing the parasite to disseminate to the liver and form abscesses. An in vitro model is used to study ...
Nohturfft A A Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas 75235, - - 1996
Oxygenated sterols such as 25-hydroxycholesterol kill Chinese hamster ovary cells because they inhibit the proteolytic processing of sterol regulatory element binding proteins (SREBPs), a pair of membrane-bound transcription factors that activate genes controlling cholesterol synthesis and uptake from lipoproteins. The unprocessed SREBPs remain membrane-bound, they cannot activate the cholesterol biosynthetic ...
Tesfaigzi J - - 1996
A family of small proline-rich proteins (SPR1s) is induced in cells undergoing squamous differentiation. Because SPR1 mRNA is detected in mesenchymal nasal cells of rats exposed to cigarette smoke, expression of this mRNA in other nonsquamous cells and tissues was investigated. Using PCR, low levels of SPR1 mRNA were identified ...
Sánchez-Góngora E - - 1996
Chinese hamster ovary cells were stably transfected with rat liver S-adenosylmethionine synthetase cDNA. As a result, S-adenosylmethionine synthetase activity increased 2.3-fold, an effect that was accompanied by increased S-adenosylmethionine, a depletion of ATP and NAD levels, elevation of the S-adenosylmethionine/S-adenosylhomocysteine ratio (the methylation ratio), increased DNA methylation and polyamine levels ...
Endo T A - - 1996
A mammalian plasma membrane protein(s) which catalyzes ATP-dependent transbilayer movement (flip-flop) of phosphatidylserine (PS) has been suggested to be involved in the formation and maintenance of membrane lipid asymmetry. Flip-flop of PS in the cell surface of nucleated cells was first described by O. C. Martin and R. E. Pagano ...
Schiedner G - - 1996
Human adenovirus type 12 (Ad12) induces undifferentiated sarcomas in neonate Syrian hamsters and hence presents a suitable model for studies of the molecular mechanism of viral oncogenesis. Since we submit that an understanding of the early steps in the interaction between Ad12 and hamster cells might shed light on the ...
Chazenbalk G D - - 1996
The complementary DNA for the human TSH receptor (TSHR) translated region was amplified in the genome of stably transfected Chinese hamster ovary (CHO) cells using a dihydrofolate reductase minigene. Immunoprecipitation of TSHR in whole cells precursor-labeled with [35S]methionine and [35S]cysteine revealed an approximately 10-fold increase in TSHR expression in cells ...
Hakoda M - - 1996
In vivo somatic mutations have been detected at several human loci by using clonal cultures of peripheral blood T-cells. It has not been fully understood whether or not the somatic mutations in T-cells are similar to those of other cell types. To address this issue, we cloned, from human peripheral ...
Doty R T - - 1996
CD28 provides a major costimulatory signal to T cells when it is cross-linked with mAb, immobilized recombinant ligand (CD80Ig or CD86Ig), or ligand-bearing cells but not when it is bound by specific Fab fragments or monomeric ligand. We wanted to determine how monomeric CD80 could cross-link CD28 since CD80 is ...
Kargman S - - 1996
Selective inhibitors of prostaglandin synthase-2 (PGHS-2) possess potent anti-inflammatory, antipyretic, and analgesic properties but demonstrate reduced side-effects (e.g. gastrotoxicity) when compared with nonselective inhibitors of PGHS-1 and -2. We investigated the mechanism of the differential inhibition of human PGHS-1 (hPGHS-1) and -2 (hPGHS-2) in intact cells by nonsteroidal anti-inflammatory drugs ...
Galli A - - 1996
A wide variety of carcinogens including Ames assay (Salmonella) positive as well as Salmonella-negative carcinogens induce intrachromosomal recombination (DEL recombination) in strain RS112 of Saccharomyces cerevisiae. It has been previously shown that the Salmonella-positive carcinogens ethyl methanesulfonate (EMS), methyl methanesulfonate (MMS) and 4-nitroquinoline-N-oxide (4-NQO) and the Salmonella-negative carcinogens safrole, benzene, ...
Authier F - - 1996
We have investigated the biosynthesis, subcellular location and expression of insulin-degrading enzyme (IDE). a type-I peroxisomal protease, in semi-permeabilized hepatoma cells using pulse-chase experiments, non-denaturing immunoprecipitation protocols and Northern-blot analyses. In HcpG2 cell lysates prepared from cells radiolabelled with Tran[35S]-label, immunoprecipitated IDE was observed immediately after a 5 min pulse ...
Sanchez-Bueno A - - 1996
Aequorin, a photoprotein which is regenerated from apoaequorin by incubation with coelenterazine, emits light when it binds Ca2+. The aim of this study was to determine if apoaequorin could be used in adherent mammalian cells for measuring cytosolic Ca2+, and imaging Ca2+, at the single cell level. Chinese hamster ovary ...
Swedmark S - - 1996
Glutathione S-transferase (GST) of class Pi (GST Pi) is known to detoxify the mutagenic and carcinogenic (+)-anti-benzo[a]pyrene-7, 8-dihydrodiol 9,10-epoxide [(+)-anti-BPDE] by conjugation with glutathione. Previously, we have shown that Chinese hamster V79 cells contain GST Pi, but seem to lack the capacity to conjugate (+)-anti-BPDE, although these cells do conjugate ...
Nickel W - - 1996
Forskolin has been shown to prevent the effects brefeldin A (BFA) exerts on many mammalian cells with respect to the disassembly of the Golgi apparatus as well as an increase of sphingomyelin synthesis (Lippincott, S. J., Glickman, J., Donaldson, J. G., Robbins, J., Kreis, T. E., Seamon, K. B., Sheetz, ...
Fan S R - - 1996
Arsenic, widely distributed throughout our environment, is a well-established human carcinogen. We report here that squalene, a natural fish oil, is a potential agent in the reduction of sodium arsenite-induced sister chromatid exchange (SCE) and micronuclei in Chinese hamster ovary (CHO-K1) cells. Squalene dose-dependently inhibited sodium arsenite-induced SCE. At the ...
Conner E A - - 1996
Genomic stability was investigated in Chinese hamster ovary (CHO) and human hepatocellular carcinoma HepG2 cells selected for growth in the presence of cytotoxic concentrations of N-(phosphonacetyl-L-asparate) (PALA). In CHO cells selected with 9 x LD50 PALA the carbamyl p-synthetase, aspartate transcarbamylase and dihydroorotase (CAD) gene complex was amplified two-fold while ...
Meschini R - - 1996
Chinese hamster lung embryonic cells (CL1) were treated with colchicine in order to induce endoreduplication and subsequently with mitomycin-C (MMC) to induce exchanges within the diplochromosome. The use of chromosomal differential staining through incorporation of 5-bromodeoxyuridine, resulting in only one stained chromatid, has allowed the analysis of all classes of ...
Mellgren R L - - 1996
A Chinese hamster ovary cell line (CHOp) was cultured in the presence of benzyloxycarbonyl-Leu-Leu-Tyr diazomethyl ketone (ZLLY-CHN2), to select for resistance to this cell-permeant calpain inhibitor. A clone isolated after several courses of exposure (SHI cells) demonstrated decreased sensitivity to ZLLY-CHN2 toxicity and a decreased growth rate. SHI cells also ...
Cui Z - - 1996
We have investigated the cell death of a Chinese hamster ovary mutant (MT-58) with a thermo-sensitive CTP:phosphocholine cytidylyltransferase, the rate-limiting enzyme of the CDP-choline pathway for phosphatidylcholine biosynthesis (Esko, J. D., Wermuth, M. M., and Raetz, C. R. H. (1981) J. Biol. Chem. 256, 7388-7393). After MT-58 cells were shifted ...
Curry P T - - 1996
The bacterial gyrase inhibitors, ciprofloxacin and PD 124816, were tested for clastogenic and aneugenic activity in V79 Chinese hamster lung cells in vitro. Cells were exposed for 3 h, washed free of drug, and subcultured for assessment of various endpoints. For structural chromosomal aberration (SCA) analysis, cells were incubated for ...
Martoglio A M - - 1996
Oviductal non-ciliated secretory epithelial cells, under hormonal stimulation, synthesize and secrete a family of glycoproteins referred to as oviductins. These glycoproteins are found in oviductal fluid in several mammalian species, and have been localized in the oviduct, and in the zona pellucida of ovulated oocytes. In the golden hamster, this ...
Guo Q - - 1996
At the nonpermissive temperature of 39.5 degrees C, the Chinese hamster ovary cell conditionally lethal, temperature-sensitive (ts) mutant ldlF exhibits the following defects: rapid degradation of low density lipoprotein receptors, disruption of ER-through Golgi transport, and disintegration of the Golgi apparatus. All of these are corrected by transfection with an ...
Lee K H - - 1996
Engineering of the cell cycle can be an effective means for bypassing growth factor requirements of animal cells. Cloned human E2F-1 from Nalm 6 cells was subcloned into pRc/CMV and transfected into Chinese hamster ovary (CHO) cells. Ten stable transfectant clones isolated from cells cultured under neomycin-resistance selection pressure all ...
German J - - 1996
Cells with abnormally high rates of sister-chromatid exchange (SCE) are uniquely characteristic of Bloom's syndrome (BS). However, in one in five persons a minor population of cells with a low-SCE phenotype circulates in the blood. The origin and significance of the low-SCE cells in BS have never been understood, although ...
Folle G A - - 1996
The restriction endonucleases (REs) AluI and BamHI were electroporated into Chinese hamster ovary (CHO) cells during S phase of the cell cycle and breakpoints in G-banded metaphases were mapped to Giemsa-light or -dark bands or to band junctions. The majority of AluI- and BamHI-induced breakpoints were located in Giemsa-light bands. ...
Deshpande A - - 1996
We investigated the relationship between nuclear hits by alpha particles and the subsequent occurrence of sister chromatid exchanges (SCEs) in normal human diploid lung fibroblasts (HFL1). Cells were exposed to 238Pu alpha particles at doses ranging from 0.4-12.9 cGy and subsequently analyzed for SCEs. A significant increase in SCE frequency ...
Telleman P - - 1996
The mitomycin C (MMC)-hypersensitive Chinese hamster V79 cell mutant V-H4 has a cellular phenotype similar to Fanconi anemia (FA), and has been shown to be homologous to FA group A. To examine consequences of the defect in V-H4 cells on spontaneous mutagenesis, we studied the frequency and nature of spontaneous ...
Lee C H - - 1996
The purpose of this study is to explore the mutual interactions among the chemical ingredients of betel quid including arecoline, sodium fluoride, catechin and glycyrrhizin in producing genotoxicity on Chinese hamster ovary (CHO) cells using the micronucleus method. Our results show that arecoline at a rather low concentration of 0.2-2 ...
Wahl M L - - 1996
As an in vitro model for the low extracellular pH (pHe) which has frequently been observed in tumors, cell lines have been grown in a low-pH medium in order to allow cell adaptation to that milieu. Two Chinese hamster cell lines [Chinese hamster ovary (CHO) and Chinese hamster ovarian carcinoma ...
Simmons J A - - 1996
The effects of alpha-particle irradiation on hamster and human lung cells have been studied. In both cases two end points were taken, cell death and the induction of chromosome aberrations. The hamster cells were common stock V79 cells; the human ones were freshly derived from fetal material. For both types ...
Wakazono Y - - 1996
The effect of mutational loss of thymidine kinase (TK) on the sensitivity to alkylating agents was investigated in promyelocytic, HL-60, and T-lymphoblastoid, Molt-3, human leukemia cell lines. Although both cell lines exhibited approx. 1% residual TK activity, only HL-60 TK deficient cells had a decreased intracellular TTP pool, i.e., 20% ...
Saunders P P - - 1996
Benzamide riboside (3-(1-deoxy-beta-D-ribofuranosyl)benzamide, BR) a new analog of nicotinamide riboside, is toxic to Chinese hamster ovary cells and inhibits guanine nucleotide synthesis in a manner comparable to that of tiazofurin (2-beta-D-ribofuranosylthiazole-4-carboxamide). Adenosine kinase deficient cells demonstrate slight resistance but retain the ability to form the NAD analog, benzamide adenine dinucleotide ...
Ariza M E - - 1996
Little is known at the molecular level concerning the genotoxic effects following the acute exposure of eukaryotic cells to low concentrations of lead (II) or mercury (II). There have been conflicting reports concerning the mutagenic potential of these heavy metals, and there have not been any studies performed to determine ...
Dobrovolsky V N - - 1996
A tk+/- mouse embryonic stem (ES) cell line, designated 1G2, has been created in which one allele of the thymidine kinase (tk) gene was inactivated by targeted homologous recombination. This line is an analog of the mouse lymphoma tk+/- L5178Y cell line, which is used widely to assess the mutagenicity ...
Fischer B - - 1996
The N-glycan patterns of recombinant human coagulation factors II (rF-II) and IX (rF-IX), derived from both transfected Chinese hamster ovary (CHO) cells and African green monkay (Vero) cells produced at industrial scale, were analyzed by binding to carbohydrate-specific lectins and were compared with the glycan structure of human plasma-derived coagulation ...
Stevens V L - - 1996
Mutant cell lines defective in the biosynthesis of glycosylphosphatidylinositol (GPI) described to date were isolated by selecting cells which no longer expressed one or more endogenous GPI-anchored proteins on their surface. In this study, a new mutant in this pathway was isolated from ethylmethane-sulphonate-mutagenized Chinese hamster ovary cells stably transfected ...
Potvin B - - 1995
LEC29.Lec32 is a glycosylation mutant that was isolated from a selection of mutagenized Chinese hamster ovary (CHO) cells for lectin resistance. Compared with LEC29 CHO cells, the double mutant exhibited an unusually high sensitivity to the toxic lectin, ricin, indicating increased exposure of galactose residues on cell surface carbohydrates. Structural ...
Hakoda M - - 1995
Lesch-Nyhan syndrome is caused by a severe genetic deficiency of hypoxanthine phosphoribosyltransferase (HPRT) and is characterized by central nervous system disorders, gout, and in some cases, macrocytic anemia. Women heterozygous for HPRT deficiency are healthy but their somatic cells are mosaic for enzyme deficiency owing to random inactivation of the ...
Wang L - - 1995
Major insulin signals such as stimulation of glucose uptake and DNA synthesis and modification of hexose metabolism are mediated by the tyrosine-phosphorylated insulin receptor substrate-1 (IRS-1; pp180) in many species of cells. We cloned cDNA encoding a 190-kDa IRS-1-like protein (pp190) in simian COS cells and which is slightly larger ...
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