Search Results
Results 651 - 700 of 1490
< 9 10 11 12 13 14 15 16 17 18 19 >
Sawada M - - 1993
To the cell line (A-15) expressing monkey P4501A1, which was developed from a Chinese hamster fibroblast cell line (CHL), a guinea pig [corrected] cDNA encoding NADPH-cytochrome P450 reductase was introduced and the transformants (designated AR-10, AR-13, and AR-18) stably expressing the reductase of increased level were established. The high-level expression ...
Jaworska A - - 1993
The activities of reactive oxygen species scavenging enzymes, superoxide dismutases (SODs) and catalase (in cells of two melanomas (mouse B16 and human SK23) and in Chinese hamster ovary (CHO) cells were examined. Melanoma cells are relatively depleted in activities of superoxide dismutases and catalase as compared to CHO cells. Short ...
McDaniel L D - - 1993
Aminoglycosides are a class of antibiotics that interfere with protein translation. Geneticin and hygromycin are two such agents, which have been shown to exhibit highly toxic effects in mammalian cells. Cloned bacterial genes, which inactivate these antibiotics, have facilitated the establishment of dominant selection systems, which are widely used in ...
Richer C L - - 1993
The present study was undertaken to investigate, both in vitro and in vivo, the genotoxic potential of short-term low-level exposure to toluene, xylene, and their mixture, for which information is limited at the present time. Five adult healthy white men were exposed for 7 consecutive hours per day over 3 ...
Hayakawa T - - 1992
The in vivo biological activity of four pharmaceutical preparations of recombinant human erythropoietin was compared. Two of the erythropoietins were produced by Chinese hamster ovary cells, CHO-K1, and the others were produced by mouse mammary cells, C127, and baby hamster kidney cells, BHK-21. The activities of the analogues were estimated ...
Heddle J A - - 1992
The frequency of mutant cells observed in a series of experiments in which primary cells were isolated from untreated or solvent control animals are reported. The mutants detected are thioguanine-resistant lung fibroblasts isolated de novo from Chinese hamsters or Fischer 344 rats. The results in the two species were very ...
Dare E - - 1992
Two APRT- clones (V79-E3 and V79-E1A) were isolated from V79 hamster fibroblasts treated with ethyl methanesulfonate. Selection involved sequential exposure of the mutagenized cells to the adenine analogues 8-azaadenine and 2,6-diaminopurine. To examine the influence of APRT deficiency on cell metabolism we determined the size and turnover of adenine ribonucleotide ...
Stoll J - - 1992
B4-2-1 cells (Lec15 cells) are Chinese hamster ovary cells deficient in mannosylphosphoryldolichol synthase activity. They synthesize the truncated lipid intermediate Man5GlcNAc2-P-P-dolichol rather than the Glc3Man9GlcNAc2-P-P-dolichol synthesized by wild-type cells. In this report we present evidence that these cells did synthesize glucosylated Man5GlcNAc2-P-P-dolichol, but this species represented only a minor fraction ...
Piñero J - - 1992
The influence of low doses of 5-bromodeoxyuridine (BrdU) on the occurrence of sister chromatid exchanges (SCEs) during the first cell cycle, when unsubstituted DNA templates replicate in the presence of the halogenated nucleoside (SCE1) has been assessed in third mitosis (M3) Chinese hamster ovary (CHO) cells showing three-way differential (TWD) ...
Hanada K - - 1992
We previously isolated a temperature-sensitive Chinese hamster ovary cell mutant (strain SPB-1) with thermolabile serine palmitoyltransferase, which is involved in the first step of sphingolipid synthesis (Hanada, K., Nishijima, M., and Akamatsu, Y. (1990) J. Biol. Chem. 265, 22137-22142). In this study, sphingolipid-deficient culture medium was used to examine the ...
Lee S T - - 1992
We have introduced two mutations into a full-length human pro-alpha 1(I) cDNA that delete 114 amino acids or the entire 139 amino acids of the N-propeptide domain. Wild-type and mutated versions of the cDNA were introduced into cultured Chinese hamster lung (CHL) cells, which do not produce endogenous type I ...
An J - - 1992
We have investigated the roles of reactive oxygen species (ROS) in bleomycin (BLM)-induced gene mutations in Chinese hamster ovary (CHO) cells using a superoxide dismutase (SOD) inhibitor, triethylenetetramine (TRIEN), and a SOD mimic, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEM-POL), to lower and increase intracellular 'SOD activity', respectively. Pretreatment of CHO cells with TRIEN (1 ...
Nagasawa H - - 1992
The induction of sister chromatid exchanges (SCE) was examined in Chinese hamster ovary cells irradiated in the G1 phase of the cell cycle with alpha-particles from a plutonium-238 source. A significant increase in the frequency of SCE occurred with doses as low as 0.31 mGy (31 millirads). Although 30% of ...
Suzuki S - - 1992
We evaluated whether insulin-receptor tyrosine kinase activity is required for activation of PDH, insulin-induced hydrolysis of PIG and generation of IG and 1,2-DAG. For the analysis, we used stable-transfected CHO cell lines expressing wild-type human insulin receptor (CHO-wt cells) or the mutant receptor (Val996) that lacks tyrosine kinase activity (CHO-mut ...
Wang R H - - 1992
A new method for isolating mutants defective in fluid-phase endocytosis has been developed based on the observation that endocytosed horseradish peroxidase can be made lethal to cells. The method was used to isolate a mutant from Chinese hamster ovary cells, termed HRP-1, that was temperature-sensitive for viability and had a ...
Murley J S - - 1992
WR-1065 (2-[(aminopropyl)amino]ethanethiol) reduces cytotoxic and mutagenic effects caused by exposure of cells to radiation and chemotherapeutic drugs, but the mechanisms involved are not fully known. We have observed an accumulation of cells in G2 in WR-1065 treated Chinese hamster ovary cells grown in alpha-minimal essential medium, while others have found ...
Yasui L S - - 1992
The survival of parental Chinese hamster ovary (CHO) K1 cells and the DNA double strand break (DSB) repair deficient mutant, xrs-5 was determined after accumulation of 125I decays. Both CHO and xrs-5 cells were extremely sensitive to accumulated 125I decays. The D0 values for CHO and xrs-5 cells were 40 ...
Shimozawa N - - 1992
Generalized peroxisome-deficient disorders including cerebro-hepato-renal Zellweger syndrome, neonatal adrenoleukodystrophy, and infantile Refsum disease are autosomal recessive diseases, where catalase-containing particles (peroxisomes) are morphologically absent. We previously isolated two Chinese hamster ovary (CHO) cell mutants (Z24 and Z65) that resemble the fibroblasts from patients with such diseases, in their defective peroxisome ...
Iannelli D - - 1992
A procedure is described for the selection of mouse Lyt2- mutant cells. The procedure is based upon repeated cycles of selection with rat monoclonal antibodies to the Lyt2 antigen and magnetic particles coated with goat anti-mouse IgG. Stable Lyt2- mutant clones were derived from cells previously mutagenized with X rays ...
Falcoón J - - 1992
Trout pineal photoreceptor cells were dissociated by trypsin-DNase digestion and further purified by a Percoll gradient centrifugation. Total cells or purified photoreceptor cells were then embedded in a collagen gel, or layered on culture-treated polycarbonate membranes, or maintained in suspension, with RPMI 1640 medium or BGjb medium. It has been ...
Yuan H - - 1992
A study of some factors affecting sister-chromatid differentiation (SCD) and sister-chromatid exchanges (SCE) in Hordeum vulgare is reported. After we studied the influence of 5-fluorodeoxyuridine (FdU) and growth temperature on SCE in barley cells, and the effect of FdU, growth temperature, the growth time of plant cells in 5-bromo-2-deoxyuridine (BrdU) ...
Swedmark S - - 1992
The glutathione transferases (GST) belonging to class pi are primarily responsible for the intracellular detoxification of the highly mutagenic and carcinogenic compound (+)-7 beta, 8 alpha-dihydroxy-9 alpha, 10 alpha-oxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE). The aim of the present investigation was to study the nature and function of the GST pi gene in relation ...
Numata M - - 1992
1-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-3-(2-chloroethyl)-3- nitrosourea hydrochloride (ACNU) causes chloroethylation of DNA strand followed by cross linking through an ethylene bridge. We recently isolated two ACNU sensitive mutants from mutagenized Chinese hamster ovary cells, and found them to be new drug sensitive recessive mutants (Hata et al. 1991). The O6-methyl guanine DNA methyl transferase ...
Dimitriadis V K - - 1992
Hamster airway epithelial secretory cells were investigated by light and electron microscopic cytochemistry to study possible changes in their carbohydrate content induced by human neutrophil elastase (HNE), an agent known to cause replacement of Clara cells by mucous cells in hamster bronchi. Characterization of secretory cell carbohydrates by the AB/PAS, ...
Blackall D P - - 1992
Chinese hamster ovary (CHO) cells were transfected with the wild-type, M allele of glycophorin A cDNA. The binding of human alloantibodies to recombinant glycophorin A was assessed with a modified hemagglutination-inhibition assay. Patient sera were incubated with acetone powders derived from CHO cells, and the adsorbed supernatants were tested in ...
Morita T - - 1992
It has been reported that low pH itself can be clastogenic to Chinese hamster ovary cells or mouse lymphoma L5178Y cells. On the other hand, there was no indication that low pH is clastogenic to rat or human lymphocytes. Therefore, in order to evaluate the generality of clastogenicity of low ...
Kalsner I - - 1992
Recombinant human soluble low affinity receptor for the Fc portion of IgE (sFc epsilon RII/sCD23) was produced in Saccharomyces cerevisiae or Chinese hamster ovary cells and subjected to carbohydrate analysis. Applied methods included analytical SDS-PAGE, reversed phase HPLC, methylation analysis and sequential degradation with exoglycosidases. The results revealed that sFc ...
Osmak M - - 1992
Chinese hamster V79 cells were irradiated daily with 0.3 Gy of gamma-rays 5 times per week for 12 weeks (total 18 Gy). These cells were challenged with an additional dose of 15. Gy gamma-rays or treated with 5 micrograms/ml of mitomycin C (MMC) for 2 h. In spite of the ...
Bauchinger M - - 1992
The clastogenicity of the sensory irritant 2-chlorobenzylidene malonitrile (CS) to V79 Chinese hamster cells was investigated at various exposure conditions. CS efficiently induced chromatid-type aberrations in a dose-dependent manner provided the cells could run through at least one or two S-phases during a 20-h exposure over a 3-h exposure followed ...
Yoo H - - 1992
The repair-associated gene XRCC1 was previously cloned by complementing the hamster mutant EM9, which has a high rate of spontaneous SCE and hypersensitivity to DNA damaging agents. In analyzing XRCC1 gene expression, similar levels of steady-state mRNA were found in normal cells, Bloom's syndrome cells with altered SCE, and in ...
Benjannet S - - 1992
Proprotein and prohormone processing at pairs of basic residues is generally thought to be both tissue- and precursor-specific and to be developmentally regulated. Furin, PC1 (also called PC3), and PC2 represent three recently discovered subtilisin-like proteinases which cleave a number of precursors at the same pairs of basic residues normally ...
Delclos K B - - 1992
6-Nitrochrysene, 6-aminochrysene and several of their metabolites were assayed for mutagenic activity at the hypoxanthine-guanine phosphoribosyl transferase (hprt) locus in DNA-repair-proficient Chinese hamster ovary (CHO-K1) cells and excision-repair-deficient CHO-UV5 cells. Mutagen-DNA adducts were analyzed by 32P-postlabeling in cells treated under the conditions of the mutagenicity assay and compared with the ...
Kaiden A - - 1992
The addition of oligosaccharide to asparagine residues of soluble and membrane-associated proteins in eukaryotic cells involves a polyisoprenoid lipid carrier, dolichol. In Chinese hamster ovary cells, the major isomer of this polyisoprenol has 19 isoprenyl units, the terminal one being saturated. Our laboratory has developed a procedure to analyze the ...
Sakaguchi K - - 1992
Fanconi anemia is a human inherited disease that is characterized by cellular hypersensitivity to DNA cross-linking agents. A number of potential experimental models for that disorder have been developed by selecting mutants that are hypersensitive to bifunctional mutagens. The six mutants of that class in Drosophila, all of which map ...
Wernicke D - - 1992
In order to establish a mammalian cell expression system with a minimum of selection steps and a stable expression of microgram amounts of recombinant protein (human tissue-type plasminogen activator mutants and chimeric proteins) per 10(6) cells per day, we investigated Chinese hamster ovary cells and the dihydrofolate reductase-deficient Chinese hamster ...
Moore S E - - 1992
Studies on N-linked oligosaccharide processing in the mouse lymphoma glucosidase II-deficient mutant cell line (PHAR2.7) as well as the parent BW5147 cells indicated that the former maintain their capacity to synthesize complex carbohydrate units through the use of the deglucosylation mechanism provided by endomannosidase. The in vivo activity of this ...
Zoeller R A - - 1992
We have used a fluorescence-activated cytotoxicity protocol, 9-(1'-pyrene)nonanol (P9OH)/UV selection (Morand, O. H., Allen, L.-A. H., Zoeller, R. A., and Raetz, C. R. H. (1990) Biochim. Biophys. Acta 1034, 132-141), to isolate a series of plasmalogen-deficient mutants in a murine, macrophage-like cell line, RAW 264.7. Three of these mutants, RAW.7, ...
Chae Y H - - 1992
Biochanin A, an isoflavone, has previously been shown to inhibit the metabolic activation of the carcinogen benzo[a]pyrene (B[a]P) to metabolites that bind to DNA in hamster embryo cells and are mutagenic in Chinese hamster V79 cells. To determine the structural features required for this activity and to attempt to find ...
Brüning A - - 1992
Radioactively labeled brefeldin A was used to probe for proteins that interact with this metabolite. The most prominent protein labeled after in vivo incubation of Chinese hamster ovary cells with [3H]brefeldin A turned out to have an apparent molecular mass of 26 kDa. Radioactive peptides derived from the [3H]brefeldin A-labeled ...
Negrutskii B S - - 1992
We have recently proposed that aminoacyl-tRNA is channeled during protein synthesis in vivo--i.e., it is directly transferred among the components of the protein-synthesizing machinery and does not mix with aminoacyl-tRNA molecules introduced from outside the cell. To understand the structural basis for these functional properties, we have examined the disposition ...
Pavlica M - - 1992
Comparative studies of the effect of benzyladenine (BA) on the yeast Saccharomyces cerevisiae, the bacterium Salmonella typhimurium, the shallot Allium ascalonicum and Chinese hamster fibroblast cells were performed. The tested substance had no mutagenic activity on yeast, bacteria and cultured fibroblast cells. Changes in mitotic activity and cell division abnormalities ...
Onfelt A - - 1992
V79 Chinese hamster cells were found to produce significant amounts of acetylcholine. Asynchronously growing V79 cells were treated with five different antagonists to cholinergic receptors: atropine and scopolamine, which are inhibitors of muscarinic receptors, and mecamylamine, d-tubocurarine and alpha-bungarotoxin, which are inhibitors of nicotinic receptors. All compounds caused a slight ...
Stenberg K - - 1992
The effect of galactose-6-mustard (G-6-M) on cell growth and cell cycle kinetics was studied in murine P388 leukemia and Chinese hamster ovary (CHO) cells in vitro and compared with the effect of L-phenylalanine mustard (L-PAM). The IC50 values of G-6-M for the P388 and CHO cells were 10 and 100 ...
Nikolai T J - - 1992
Adherent cells can be cultivated in a stirred-tank bioreactor by attaching to microcarriers. Macroporous microcarriers, with their intraparticle space and surface area for cell growth, can potentially support a higher cell concentration than conventional microcarriers, which support cell growth only on the external surface. Chinese hamster ovary (CHO) cells and ...
Barbour S - - 1992
We have previously shown that the lateral diffusion, D, of the class I Major Histocompatibility Complex (MHC) glycoprotein H-2Ld is constrained by its glycosylation, when expressed in mouse L-cells. Removal of one or more of the 3 N-linked oligosaccharides of H-2Ld glycoproteins results in an increase in D. In order ...
Smith F L - - 1992
High energy shock waves produced by a piezoelectric lithotripter, (EDAP LT.01) and an electrohydraulic lithotripter, (Dornier HM3) were examined for their effects on Chinese hamster ovary cells in suspension. The EDAP caused acute lactate dehydrogenase release, consistent with severe membrane disruption in a proportion of cells, with the remaining proportion ...
Rodriguez-Colunga M J - - 1992
We have investigated the development of the Harderian glands of female Syrian hamsters from birth to 8 months of age. The effects of melatonin injections on Harderian gland histology and porphyrin deposits of female hamsters exposed to two different temperatures were also studied. The morphology of the Harderian glands from ...
Madden K R - - 1992
The 3645-base pair human topoisomerase I complementary DNA (cDNA) clone isolated by D'Arpa et al. (Proc. Natl. Acad. Sci. USA, 85:2543-2547, 1988) and a mutated version of the cDNA encoding a protein with phenylalanine instead of tyrosine at position 723 have been overexpressed 2- to 5-fold in stably transfected baby ...
Turchi G - - 1992
Recently numerous attempts have been made to reduce the use of vertebrate animals in laboratory experiments to evaluate general and acute toxicity, mutagenesis and teratogenesis of new drugs or chemicals. One common approach is to use established, proliferating cell lines that preserve differentiated functions such as the competence to metabolize ...
Meulien P - - 1992
The cloning of the cDNA encoding von Willebrand factor (vWF) has revealed that it is synthesized as a large precursor (pre-pro-vWF) molecule and it is now clear that the prosequence or vWAgII is responsible for the intracellular multimerization of vWF. We have cloned the complete vWF cDNA and expressed it ...
< 9 10 11 12 13 14 15 16 17 18 19 >