Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
|---|
| tetracycline-induced mutation in cultured chinese hamster cells. | after tetracycline hydrochloride (tc) treatment for 48 h, we obtained 8-azaguanine-resistant mutants in a population of cultured chinese hamster cells. optimal expression of mutation was reached after about 5 days, and mutation frequency remained constant thereafter. there was a gradual increase in the yield of mutants with increasing doses of tc, and measurable yield was observed at a dose as low as 10 microgram of tc per ml. when the cells, before or after the tc treatment, were grown in prese ... | 1982 | 7110160 |
| decreased incidence of gap junctions between chinese hamster v-79 cells upon exposure to the tumor promoter 12-o-tetradecanoyl phorbol-13-acetate. | 1982 | 7084321 | |
| heat protection by glycerol in vitro. | heating of either chinese hamster ovary or hela cells in medium containing glycerol protected against thermal killing. above glycerol concentrations of 100 mm, protection of chinese hamster ovary cells increased in a concentration-dependent manner. exposure to glycerol only, before or after heating at 45 degrees, did not protect against cell killing. glycerol protection against thermal damage was also expressed at the subcellular level. the fractional increase in the protein:dna ratio for nuclei ... | 1982 | 7074597 |
| down-regulation of the hexose transport system: metabolic basis studied with a fibroblast mutant lacking phosphoglucose isomerase. | down-regulation ("curb") of hexose transport in chinese hamster lung fibroblasts has been studied in a metabolic mutant highly defective in phosphoglucose isomerase (pgi; glucosephosphate isomerase; d-glucose-6-phosphate ketol-isomerase, ec 5.3.1.9). in the parental strain (pgi+) glucose as well as glucosamine and mannose were able to elicit a curb of the hexose transport system. in the pgi mutant, only glucose was able to mediate a transport curb. the inability of glucosamine and mannose to pro ... | 1982 | 6954519 |
| dna double-strand breaks generated by the repair of x-ray damage in chinese hamster cells. | 1982 | 6288603 | |
| alteration in thermal sensitivity of chinese hamster cells by d2o treatment. | 1982 | 6283583 | |
| induction of thymidine kinase in enzyme-deficient chinese hamster cells. | previous work with chinese hamster cells suggests that thymidine kinase deficiency and loss of potential for plating in hat medium may arise by a process of mutation coupled with site-specific repression by bromodeoxyuridine at the tk locus. in this study, tk- chinese hamster cells were exposed to a series of inductors to determine whether revertants for the putative second stage originate by genetic or epigenetic change. brief exposure to 5-azacytidine resulted in massive conversion to the hat+ ... | 1982 | 6180833 |
| synergistic effect of purine derivatives on the toxicity of pyrazofurin and 6-azauridine towards cultured mammalian cells. | a novel synergistic effect of several purine derivatives such as adenine, adenosine, hypoxanthine, and guanine on the toxicity of nucleoside analogs pyrazofurin and 6-azauridine towards cultured chinese hamster ovary (cho) cells has been observed. the presence of the above purine derivatives enhanced the toxicity of pyrazofurin and 6-azauridine, in a dose dependent manner. the growth inhibitory effects of these nucleoside analogs either alone or in combination with the purine derivatives were re ... | 1982 | 6178748 |
| impaired repair capacity of dna strand breaks induced by 125i-triiodothyronine in chinese hamster cells. | 1982 | 7104009 | |
| increased hexose transport in chinese hamster ovary cells resistant to 3-o-methyl-d-glucose. | 3-o-methyl-d-glucose-resistant mutants were selected from chinese hamster ovary cells after mutagenesis with ethyl methanesulfonate. a mutant, megr24, was isolated which was significantly more resistant than the parent to 3-o-methylglucose. uptake of 50 microm d-glucose by metabolizing megr24 cells was 2- to 3-fold higher than the parental cells in the absence or presence of 100 mm 3-o-methylglucose. a study of transport of d-[3h]glucose in atp-depleted cells indicated an apparent km for d-gluco ... | 1982 | 7068670 |
| sister-chromatid exchange and chromosomal aberration induction in cultured chinese hamster cells by the monomethylbenz[a]anthracenes. | the ability of the 12 monomethylbenz[a]anthracene isomers, following their metabolism by using the cell-mediated activation system, to induce 8-azaguanine-resistant mutants, sister-chromatid exchanges (sces) and chromosomal aberrations has been measured. both the mutagenic potency and the ability of the monomethylbenz[a]anthracenes to induce sces correlated with their carcinogenic activity. none of the monomethylbenz[a]anthracenes were particularly clastogenic. | 1982 | 7144778 |
| insensitivity of 3-hydroxy-3-methylglutaryl coenzyme a reductase activity to low-density lipoprotein in concanavalin-a-resistant chinese-hamster ovary cells. | a concanavalin-a-resistant mutant of chinese-hamster ovary cells has been shown to have altered cholesterol content and 3-hydroxy-3-methylglutaryl coenzyme a reductase activity compared to wild-type and spontaneous-revertant cell lines. these changes are associated with insensitivity of the mutant reductase activity to suppression by low-density lipoprotein and impaired receptor-mediated binding and uptake of 125i-labelled low-density lipoprotein. | 1982 | 7139075 |
| folate-dependent enzymes in cultured chinese hamster ovary cells: impaired mitochondrial serine hydroxymethyltransferase activity in two additional glycine--auxotroph complementation classes. | 1982 | 7138028 | |
| genetic analysis of tumorigenesis: x. chromosome studies of transformed mutants and tumor-derived chef/18 cells. | chinese hamster embryo fibroblast cell line chef/18 is stably diploid, anchorage-dependent, has a high serum requirement, and a does not form tumors in nude mice. the chromosome constitutions of spontaneous and chemically induced anchorage-independent and/or low-serum chef/18 mutants and tumors produced in nude mice by some of these mutants are compared. we find a correlation between diploidy and nontumorigenicity among the anchorage-independent mutants but not in the low-serum mutants. one of t ... | 1982 | 7135168 |
| mutagen treatment of single chinese hamster ovary cells produces colonies mosaic for glucose-6-phosphate dehydrogenase activity. | when populations of single chinesee hamster ovary (cho) cells were exposed to the mutagen ethyl methane sulfonate (ems), allowed to grow into colonies, and stained for glucose-6-phosphate dehydrogenase (g6pd) activity, two types of unstained colonies were observed at a frequency of about on per thousand stained colonies. these negative-staining colonies consisted of (1) colonies uniformly deficient in staining activity (pure); and (2) colonies containing both stained and unstained sectors (mosai ... | 1982 | 7135167 |
| isolation of chinese hamster ovary cells with reduced unscheduled dna synthesis after uv irradiation. | a simple procedure has been worked out to obtain uv-sensitive mutants of chinese hamster ovary (cho) cells. in this procedure, conventional mutagenesis is followed by brdu--light treatment to enrich the population for uv-sensitive cells. colonies that are allowed to form subsequently are duplicated by replica plating and screened on the master plate for their uv sensitivity and their capacity to carry out uv-induced dna repair synthesis. putative mutants are isolated from the replica. with this ... | 1982 | 7135166 |
| isolation and initial characterization of the mammalian midbody. | midbodies were isolated from synchronized cultures of chinese hamster ovary (cho) cells and their protein composition was studied by means of sds page. gels of the midbodies included alpha and beta tubulins as major bands (approximately 30% of the total protein) and approximately 35 other bands, none of which constituted greater than 3.5% of the total protein. extraction of the isolated midbodies with sarkosyl nl-30- solubilized the midbody microtubules but left the central, dense matrix zone of ... | 1982 | 7130277 |
| interaction of 144ce and partial hepatectomy in the production of liver neoplasms in the chinese hamster. | 1982 | 7122833 | |
| quantification and analysis of reverse mutations at the hgprt locus in chinese hamster ovary cells. | we describe an assay for the quantification of reverse mutations at the hypoxanthine-guanine phosphoribosyltransferase (hgprt) locus in chinese hamster ovary cells utilizing the selective agent l-azaserine (as). conditions are defined in terms of optimal as concentration, cell density, and phenotypic expression time. after treatment, replicate cultures of 10(6) cells are allowed a 48-h phenotypic expression time in 100-mm plates. as (10 mum) is then added directly to the growing culture and as-r ... | 1982 | 7121497 |
| comparison of the effects of dihydroxyanthraquinone and adriamycin on the survival of cultured chinese hamster cells. | dihydroxyanthraquinone [1,4-dihydroxy-5,8-bis ((2-([(2-hydroxyethyl)amino)ethyl)amino))-9,10-anthracenedione (dhaq) (nsc 279836)] is currently being tested as a cancer chemotherapeutic agent because of its structural similarity to adriamycin (adr) and other dna-intercalating antibiotics. we have therefore studied the effect of dhaq on the survival of cultured chinese hamster cells in direct comparison to adr. both dhaq and adr produced cytotoxicity that was dependent upon the concentration and d ... | 1982 | 7105035 |
| regulation of synthesis and degradation of 3-hydroxy-3-methylglutaryl-coenzyme a reductase by low density lipoprotein and 25-hydroxycholesterol in ut-1 cells. | ut-1 cells are a clone of chinese hamster ovary cells that were selected to grow in the presence of compactin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme a reductase [mevalonate: nadp+ oxidoreductase (coa-acylating), ec 1.1.1.34]. these cells have 100- to 1,000-fold more immunoprecipitable reductase than normal. the enzyme activity is rapidly decreased when low density lipoprotein (ldl) or 25-hydroxycholesterol is added to the culture medium. in this current study, a quantita ... | 1982 | 6957860 |
| lectin affinity chromatography of glycopeptides and oligosaccharides from normal and lectin-resistant chinese-hamster ovary cells. | the [3h]mannose-labelled glycopeptides from two lectin-resistant lines of chinese-hamster ovary cells were fractionated by chromatography on lentil lectin-sepharose and concanavalin a-agarose columns and subsequently analysed by gel filtration in comparison with the glycopeptides of the parental cell line. essentially all of the [3h]mannose-labelled asparaginyl-oligosaccharides from the 'single-mutant' cells selected for resistance to phytohaemagglutinin and the 'double-mutant' cells selected fo ... | 1982 | 6890813 |
| morphometric evaluation of the hypothalamic-ovarian axis of the ketonuric, diabetic chinese hamster: relationship to the reproductive cycle. | the relationship between diabetes and the morphological alterations which occur in hypothalamic and ovarian tissue was examined in the long-term, ketonuric-diabetic chinese hamster. matched diabetic and non-diabetic control hamsters were inspected daily for changes in the reproductive cycle by vaginal lavage. on dioestrus, animals were perfused, the hypothalamus and ovaries collected, prepared for microscopy and morphometrically analyzed. the nuclei in the medial basal hypothalamus of diabetic h ... | 1982 | 6890001 |
| effect of polymers of l-lysine on the cytotoxic action of diphtheria toxin. | l-lysine and poly(l-lysine) polymers of defined sizes were tested for their effect on diphtheria toxin-mediated cytotoxicity of chinese hamster ovary cells. poly(l-lysine)8-12 and poly(l-lysine)15 were protective, whereas lysine and lysine polymers of three and four residues were not. the protection by poly(l-lysine)8-12 occurred by affecting the initial toxin receptor interaction. furthermore, poly(l-lysine)8-12 acted as a competitive inhibitor with an apparent dissociation constant of 6 x 10(- ... | 1982 | 6813267 |
| increase in k+ and alpha-aib active transport in cho cells after low [k+] treatment. | we have studied the effects of prolonged incubation in low [k+] medium (approximately 0.3 mm) on both k+ and amino acid transport in chinese hamster ovary (cho) cells. when incubated in low [k+] medium, cho cells redressed partially the loss of intracellular k+ after 12 h. after 24 h of incubation, both the activity of na+-k+-atpase in crude homogenates, and the transport capacity (vmax) for ouabain-sensitive (i.e., active) k+ influx approximately doubled. the magnitude of the ouabain-insensitiv ... | 1982 | 6287859 |
| selection of tunicamycin-resistant chinese hamster ovary cells with increased n-acetylglucosaminyltransferase activity. | chinese hamster ovary (cho) cells resistant to the antibiotic tunicamycin (tm) have been isolated by a stepwise selection procedure with progressive increments of tm added to the medium. tm inhibits asparagine-linked glycoprotein biosynthesis by blocking the transfer of n-acetylglucosamine-1-phosphate from udp-n-acetylglucosamine to the lipid carrier. the tm-resistant cells exhibited a 200-fold increase in their ld50 for tm and were morphologically distinct from the parental cells. the rate of a ... | 1982 | 6215412 |
| syntheses and modulations in the chromatin contents of histones h1 degrees and h1 during g1 and s phases in chinese hamster cells. | 1982 | 7126528 | |
| increase of a surface glycoprotein by cyclic amp in chinese hamster ovary cells. dependence on cell-cell interaction. | cell surface proteins and glycoproteins of the cho-k1 clone of chinese hamster ovary cells were radiolabeled by surface-specific reactions as well as by metabolic incorporation of glycoprotein precursors. after the proteins were separated by two-dimensional gel electrophoresis, they were quantified according to the amount of radioactivity which was associated with individual proteins spots. a glycoprotein of 133,000 daltons (p133-11) wa found to increase severalfold by the elevation of the cytop ... | 1982 | 6284757 |
| radiosensitization of hypoxic tumor cells by depletion of intracellular glutathione. | depletion of glutathione in chinese hamster ovary cells in vitro by diethyl maleate resulted in enhancement of the effect of x-rays on cell survival under hypoxic conditions but not under oxygenated conditions. hypoxic emt6 tumor cells were similarly sensitized in vivo. the action of diethyl maleate is synergistic with the effect of the electron-affinic radiosensitizer misonidazole, suggesting that the effectiveness of misonidazole in cancer radiotherapy may be improved by combining it with drug ... | 1982 | 7089580 |
| mutagenicity of n-alkyl-n-(alpha-hydroperoxyalkyl) nitrosamines in v79 chinese hamster cells in relation to alkylating activity. | mutagenicity and cytotoxicity of a series of n-alkyl-n-(alpha-hydroperoxyalkyl)-nitrosamines (alkyl = methyl, ethyl, propyl, butyl and tert-butyl) were tested in v79 chinese hamster cells to examine the effects of alkyl chain length and the mode of substitution at the alpha-carbon bearing the hydroperoxy group on the biological activities. among a series of hydroperoxymethyl compounds whose carbon bearing the hydroperoxy group is primary, the n-methyl compound was the most mutagenic and cytotoxi ... | 1982 | 7152192 |
| mutagenicity of alpha-acetoxy derivatives of n-methyl-n-benzylnitrosamine and n,n-dibenzylnitrosamine in v79 cells: a comparison between methylating and benzylating mutagens. | the mutagenicity and cytotoxicity of n-methyl-n-(alpha-acetoxybenzyl) nitrosamine, n-benzyl-n-(acetoxymethyl) nitrosamine, n-benzyl-n-(alpha-acetoxybenzyl)-nitrosamine and related compounds were examined in v79 chinese hamster cells. these three alpha-acetoxy nitrosamines were all mutagenic, the first one (a compound ultimately yielding a methylating species) being far more strongly mutagenic than the other two (compounds ultimately giving benzylating species). the alkylating or aralkylating act ... | 1982 | 7152191 |
| studies with encapsulated 125i sources. ii. determination of the relative biological effectiveness using cultured mammalian cells. | chinese hamster ovary (cho) cells, in either exponential growth or unfed plateau phase were exposed to graded doses of radiation from iodine-125 or from cesium-137 at various dose-rates and the cells were assayed for reproductive integrity. from the patterns of cell survival obtained, the relative biological effectiveness (rbe) of the emission from 125i was determined relative to 137cs. the rbe determined using cells in exponential growth was found to have a value of about 1.2, which was indepen ... | 1982 | 7141915 |
| studies with encapsulated 125i sources. i. apparatus and dosimetry for determination of relative biological effectiveness. | apparatus and dosimetry techniques have been developed which make possible studies of the biological effects of radiation from encapsulated 125i sources at clinically relevant dose rates using mammalian cells attached to culture dishes. the variation of dose rate from 125i photons as a function of distance from the interface between different materials was investigated. a polystyrene substrate changes the mean dose rate in attached cells by about 21%, depending on cell thickness. to reduce dosim ... | 1982 | 7141914 |
| interaction of razoxane and radiation on cultured chinese hamster cells. | razoxane [(+/-)-1,2-bis(3,5-dioxopiperazine-1-yl)propane] was investigated for its effects on the survival of irradiated chinese hamster fibroblasts in vitro. razoxane alone produced cytotoxicity that was dependent upon drug concentration and pulse exposure time, with a preferential lethality for cells treated while in the dna-synthetic phase. razoxane enhanced radiation-induced cell killing when used as either a pulse exposure or a continuous treatment. in asynchronous populations of cells, thi ... | 1982 | 7141912 |
| development of tetraploidy in v79 spheroids. | chinese hamster v-79-171 cells, when placed in suspension culture, spontaneously form multicell spheroids. as the spheroids enlarge the fraction of polyploid (predominantly tetraploid) cells increases and can approach 100% in very large spheroids. spheroid size, rather than age, seems to be a major determinant for increased ploidy. when cell separation techniques were used to select enriched populations of diploid and tetraploid cells, the growth rate and plating efficiency of the diploid cells ... | 1982 | 7129485 |
| involvement of higher order chromatin structures in metaphase chromosome organization. | using electron microscopy we show that the metaphase chromatin fibers of chinese hamster ovary cells form the same ionic strength-dependent higher order structures as the corresponding interphase chromatin fibers. we present evidence that such intact chromatin fibers are a prerequisite for the maintenance of the characteristic shape of metaphase chromosomes. the evidence is based on the finding that treatment of chromosomes with 0.5 m nacl, a condition which is known to remove histone h1 and whi ... | 1982 | 7127469 |
| relative sensitivity of v79 and v79/79 cells to spontaneous and induced mutation to 6-thioguanine and ouabain resistance. | the relative responses of v79 and v79/79 cells to mutation to 6-thioguanine (6tgr) and ouabain resistance (ouar) have been compared in unmutagenized cells and after exposure to ethyl methanesulphonate (ems), n-methyl-n-nitrosourea (mnu) and ultraviolet light. in the v79/79 cell line, the spontaneous frequency of 6tgr colonies but not of ouar colonies was enhanced compared to that in v79 cells. this appears to be the result of a reduced growth rate and plating efficiency of v79/79 cells and does ... | 1982 | 7121489 |
| mutagenicity of 5-diazouracil in v79 chinese hamster cells. | 1982 | 7121480 | |
| gene amplification accompanies low level increases in the activity of dihydrofolate reductase in antifolate-resistant chinese hamster lung cells containing abnormally banding chromosomes. | three independently-derived, antifolate-resistant chinese hamster lung cell lines that exhibit low level increases in dihydrofolate reductase (dhfr) activity, i.e., three- to fivefold vs. controls, have been compared with drug-sensitive cells to determine relative dhfr gene content. with a solution hybridization technique that makes use of genomic dna and a cloned double-stranded chinese hamster dhfr cdna probe, it has been found that the enzyme activity increases are associated with an approxim ... | 1982 | 7107708 |
| demonstration of recovery from the potentially mutagenic effects of ultraviolet light by replication-inhibited chinese hamster v79 cells. | the effects of replication-inhibiting conditions on the ability of chinese hamster (v79) cells to recover from the potentially mutagenic effects of ultraviolet (uv) light were investigated. v79 cells were synchronized by a new technique using a low concentration of hydroxyurea (0.2 mm), which provided a mildly-toxic, nonmutagenic method for producing large quantities of synchronized cells needed for these studies. the protocol developed for this study involved uv-irradiation of synchronized v79 ... | 1982 | 6956805 |
| repair capability and the cellular age response for killing and mutation induction after uv. | the cell-cycle response for killing and mutation induction by ultraviolet irradiation was measured in synchronous chinese hamster ovary cells (cho wild-type) and in a uv-hypersensitive mutant (43-3b) derived from this line. the cho 43-3b line shows a greatly enhanced sensitivity to killing (d0 of 0.3 as compared to 3.2 j/m2 for the wild-type), is hypermutable, and deficient in dna repair. for the wild-type, a characteristic age response is seen for killing by uv, with maximum sensitivity in earl ... | 1982 | 6889678 |
| mutagenicity of thymidine in chinese hamster cells? | 1982 | 7087996 | |
| characterization of a cell cycle mutant derived from hamster fibroblast: reversion analysis. | k12 is a temperature-sensitive (ts) mutant cell line derived from chinese hamster fibroblasts. when incubated at the nonpermissive temperature, k12 cells exhibit the following properties: (a) the cells cannot initiate dna synthesis;o (b) the synthesis of cytosol thymidine kinase is suppressed; and (c) the synthesis of three cellular proteins of molecular weights 94, 78, and 58 kdaltons is greatly enhanced. here we characterize a spontaneous revertant clone, r12, derived from the k12 cells. we se ... | 1982 | 7085753 |
| induction of chromosome damage by ultraviolet light and caffeine: correlation of cytogenetic evaluation and flow karyotype. | asynchronously growing cells of a m3-1 chinese hamster line were ultraviolet (uv) irradiated (lambda = 254 nm) with uv fluences up to 7.5 j/m(2). after irradiation cells were incubated with or without 2 mm caffeine for 20 hr, then mitotic cells were selected by mechanical shaking. their chromosomes were isolated, stained with hoechst 33258 and chromomycin a3, and measured flow cytometrically. while the fluorescence distributions of chromosomes (flow karyo-types) from cells treated with uv alone ... | 1982 | 7075394 |
| inactivation of nucleotide excision repair in chinese hamster ovary cells by exposure to an alkylating agent. | 1982 | 7063556 | |
| alkali-labile lesion and uracil-dna-glycosylase-sensitive site removal after brdurd and uvb treatment of chinese hamster cells. | 1982 | 7063552 | |
| enhanced survival and reduced mutation and aberration frequencies induced in v79 chinese hamster cells pre-exposed to low levels of methylating agents. | exposure of v79 chinese hamster cells to a single very low (sub-toxic and sub-clastogenic) dose of mnu or mnng made these cells resistant to the toxic, mutagenic and clastogenic activities of the same agents given 6 h later. cell survival was increased nearly 2-fold under optimal conditions when compared with the non-pretreated controls. aberration frequencies were reduced to nearly half the control values (cells not pretreated). this was observed for a wide range of pretreatment concentrations ... | 1982 | 7062931 |
| differences in temporal aspects of mutagenesis and cytotoxicity in chinese hamster cells treated with methylating agents and thymidine. | equitoxic concentrations of n-methyl-n'-nitro-n-nitrosoguanidine (mnng) and methyl methanesulfonate (memes) produced different frequencies of 8-azaguanine-resistant mutants and different amounts of n7-methylguanine, o6-methylguanine (m6g), and n3-methyladenine in the dna of v79 chinese hamster cells. thus, neither the cytotoxicities nor the mutagenicities of these methylating agents could be attributed solely to nitrogen or to oxygen methylations in the dna. however, mnng produced 12-fold more m ... | 1982 | 6951203 |
| the role of cavitation in the interaction of ultrasound with v79 chinese hamster cells in vitro. | suspensions of v79 cells have been irradiated with 1 mhz ultrasound at spatial average intensities up to 0.25 w cm-2. the effects seen are described in this paper. acoustic emissions at the first subharmonic of the drive frequency (0.5 mhz) were monitored during irradiation. subharmonic emission is characteristic of cavitation activity within the sample. a strong correlation was found between cell damage and a measure of the total emitted subharmonic energy. damage was assayed in terms of cell l ... | 1982 | 6950750 |
| induced thermal tolerance and heat shock protein synthesis in chinese hamster ovary cells. | 1982 | 6950748 | |
| effect of heating on lethality due to hyperthermia and selected chemotherapeutic drugs. | because the rate of heating alters various cellular events associated with exposure to hyperthermia (including the rate of cell death), effect of this parameter on the cytotoxic interaction between selected anticancer drugs and hyperthermia was studied. the drugs cisplatin, 1,3-bis(2-chloroethyl)-1-nitrosourea, and adriamycin at 42.4 degrees c and bleomycin and methotrexate at 43 degrees c were tested in chinese hamster ovary (cho) cells in vitro. heating times ranged from less than 3 minutes (i ... | 1982 | 6950177 |
| overproduction of dihydrofolate reductase and gene amplification in methotrexate-resistant chinese hamster ovary cells. | stable isolates of chinese hamster ovary cells that are highly resistant to methotrexate have been selected in a multistep selection process. quantitative immunoprecipitations have indicated that these isolates synthesize dihydrofolate reductase at an elevated rate over its synthesis in sensitive cells. restriction enzyme and southern blot analyses with a murine reductase cdna probe indicate that the highly resistant isolates contain amplifications of the dihydrofolate reductase gene number. dep ... | 1982 | 6287233 |
| on the contribution of the mitochondrial genome to the growth of chinese hamster embryo cells in culture. | the present results demonstrate that chinese hamster embryo cell populations in culture can be adapted to grow in the presence of chloramphenicol. it is shown that tryptose phosphate broth and uridine, one of its components, prevent the growth inhibitory effect of the drug. study of some respiratory parameters (cytochrome c oxidase, cytochrome spectra, oxygen consumption) indicated that neither the broth nor uridine prevented the inhibitory effect of chloramphenicol on mitoribosomal protein synt ... | 1982 | 6282420 |
| animal cells dependent on exogenous phosphatidylcholine for membrane biogenesis. | a chinese hamster ovary cell (cho) mutant (strain 58), defective in cdp-choline synthetase (cholinephosphate cytidylyltransferase; ctp:cholinephosphate cytidylyltransferase, ec 2.7.7.15), is temperature sensitive for growth and contains less than half of the normal amount of phosphatidylcholine under nonpermissive conditions [esko, j. d. & raetz, c. r. h. (1980) proc. natl. acad. sci. usa 77, 5192-5196]. we now report that the addition of 40 microm egg phosphatidylcholine or lysophosphatidylchol ... | 1982 | 6281780 |
| sister-chromatid exchanges and cell-cycle delay in chinese hamster v79 cells treated with 9 organophosphorus compounds (8 pesticides and 1 defoliant). | significant increase of sister-chromatid exchanges (sce) in v79 cells treated with 2 organophosphorus pesticides (opp), fenthion and oxydemeton-methyl, was observed. the other 7 compounds (6 opp and 1 defoliant) namely, amaze, azinphos-methyl, bolstar, def-defoliant, fensulfothion, monitor and nemacur caused no increase of sce frequencies at the doses tested. all the compounds except fensulfothion and oxydemeton-methyl induced cell-cycle delay in varying degrees. cell-cycle delay caused by an op ... | 1982 | 6211614 |
| diesel-exhaust-particle extract enhancement of chemical-induced mutagenesis in cultured chinese hamster ovary cells: possible interaction of diesel exhaust with environmental carcinogens. | 1982 | 6178024 | |
| the relationship between dna and chromosome damage after bleomycin treatment: dose-response measurements. | the molecular basis for chromosome aberration formation has been studied using the sensitive techniques of premature chromosome condensation and dna alkaline elution. the dose response of chinese hamster ovary cells to bleomycin treatment at the dna and chromosome levels was compared. each dna elution curve showed a 2-component profile, with a more sensitive component apparent at low doses. the chromosome aberration curves also exhibited a 2-component profile when determined in g2-pcc; however, ... | 1982 | 6174861 |
| mutagenicity of 5-azacytidine and related nucleosides in c3h/10t 1/2 clone 8 and v79 cells. | to determine whether 5-azacytidine (5-azacr)-induced transformation and/or differentiation of c3h/10t 1/2 clone b (10t 1/2) cells might have a mutational basis, we studied whether 5-azacr and structurally related nucleoside analogs could mutate 10t 1/2 and chinese hamster v79 cells. in an assay for mutation to ouabain resistance in 10t 1/2 cells, which detects base substitution mutations but not frameshift mutations, 5-azacr and 6-azacytidine were not significantly mutagenic. 5-aza-2'-deoxycytid ... | 1982 | 6174215 |
| kinetics of histone endocytosis in chinese hamster ovary cells. a flow cytofluorometric analysis. | the endocytosis of histones by cultured cells was examined by flow cytofluorometry. monolayer cultures of chinese hamster ovary cells were incubated with fluorescein-labeled histone for various periods of time and then trypsinized to remove surface-bound protein. internalization followed first order kinetics with a half-time of 45 min, and was linear in histone concentration up to 80 microgram/ml. since fluorescein fluorescence decreases with decreasing ph, the fluorescence of labeled histone co ... | 1982 | 7056738 |
| the induction of specific-locus mutations and sister-chromatid exchanges by 5-bromo- and 5-chloro-deoxyuridine. | the induction of 6-thioguanine-resistant (tgr) mutants and sister-chromatid exchanges (sce) by 5-bromo- and 5-chloro-deoxyuridine (brdu and cldu) was determined with chinese hamster ovary cells in culture. over a concentration range of 0.5-200 microm, cldu treatment caused 3-5 times the number of sces found with brdu; for example, with 10 microm cldu, 60.0 +/- 14.2 sces/metaphase (mean +/- s.d.) were induced, while with 10 microm brdu, only 14.6 +/- 4.1 sces/metaphase were found. despite this di ... | 1982 | 7201072 |
| molecular dosimetry of dna damage caused by alkylation. i. single-strand breaks induced by ethylating agents in cultured mammalian cells in relation to survival. | cultured chinese hamster ovary cells were treated with ethylating agents. dna lesions giving rise to single-strand breaks (ssb) or alkali-labile sites were measured by centrifugation in alkaline sucrose gradients after lysis in alkali. 4 agents with different tendencies to ethylate preferentially either at n or o atoms were compared, namely n-ethyl-n'-nitro-n-nitrosoguanidine (enng), n-ethyl-n-nitrosourea (enu), ethyl methanesulphonate (ems) and diethyl sulphonate (des). the compounds differed g ... | 1982 | 7201070 |
| cell-specific phosphorylation of h1 histone subtypes among different chinese hamster cell lines in interphase. | the phosphorylation of h1 histone subtypes was studied in 3 chinese hamster cell lines (cho, v79, and chw). chromatographic resolution of h1 subtypes showed that all 3 cell lines contained 1 homologous (coeluting) h1 subtype (cho-1, v79-1, and chw-1) while v79 and chw cells contained 2 additional h1 subtypes not found in cho cells (v79-2,3 and chw-2,3). n-bromosuccinimide cleavage of 32p-labeled h1 subtypes demonstrated that all v79 subtypes were phosphorylated in both the nh2- and cooh-terminal ... | 1982 | 7056716 |
| further characterization of a chinese hamster ovary cell mutant defective in lanosterol demethylation. | sensitive in vitro lanosterol 14 alpha- and 4 alpha-methylsterol oxidase assays, particularly suitable for cell extracts of tissue culture cells, were developed and validated. using these assays, we showed that the biochemical lesion of mutant 215, a cholesterol-requiring chinese hamster ovary cell auxotroph isolated and partially characterized previously [chang, t. y., telakowski, c., vanden heuvel, w., alberts, a. w., & vagelos, p. r. (1977) proc. natl. acad. sci. u.s.a. 74, 832-836], was loca ... | 1982 | 7066308 |
| the fusion of trout spermatozoa with chinese hamster fibroblasts. | polyethylene glycol (peg) was used to fuse trout sperm with chinese hamster fibroblasts (chw-1102). as judged by light microscopy, peg significantly increased the number of associations between the two cell types. electron microscopy revealed that the sperm nuclei were in the cytoplasm of chw-1102 in cultures that had been treated with peg and in phagosomes of chw-1102 in cultures not treated with peg. in the cytoplasm many sperm nuclei had an extensive network of fibres whereas before fusion th ... | 1982 | 7200990 |
| effect of colcemid on the centriole cycle in chinese hamster ovary cells. | the structural changes in the centrioles in chinese hamster ovary cells were monitored by electron microscopy of whole mount preparations to investigate the effects of colcemid on the events in the centriole cycle. the population of mitotic cells increased with time of incubation with colcemid, but the arrest at mitosis by this drug was soon overcome, resulting in the formation of nuclei and a change in the shape of the cells again spreading over the substrate. the maximal mitotic index was reac ... | 1982 | 7200989 |
| [relation of the effectiveness of inducing sister chromatid exchanges to the chemical structure of the mutagen]. | the activity of 12 alkylating compounds of different chemical structure has been investigated for the induction of sister chromatid exchanges (sce) in a cell culture of chinese hamster. a linear dependence of sce upon the concentration has been found for all alkylating compounds. the activity for sce induction depends upon the chemical structure of the mutagen: benzochinone derivatives (trenimon, e39) and triazine (tem) are more effective than the derivatives of amidophosphoric acid (dimatif, th ... | 1982 | 7199497 |
| comparative misonidazole metabolism in anaerobic bacteria and hypoxic chinese hamster lung fibroblast (v-79-473) cells. | the metabolism of the radiation sensitizer misonidazole was similar in anaerobic cecal contents and hypoxic chinese hamster lung fibroblasts (v-79-473). both systems formed the amino derivative of misonidazole, [1-(2-aminoimidazol-1-yl)-3-methoxypropan-2-ol] (aim), and urea, as well as a metabolite, (2-hydroxy-3-methoxypropyl)-guanidine (g), which has not been described previously. it appears that the nitro group of misonidazole was reduced to form aim and that this compound was then hydrolyzed ... | 1982 | 7073768 |
| the regulation of carbohydrate metabolism in animal cells: isolation of starch- and maltose-utilizing variants. | chinese-hamster ovary (cho-k1) cells can grow in medium in which glucose is replaced by either maltose, trehalose, or starch. this growth is due to the presence in the medium of serum enzymes which degrade these substrates to glucose. when the enzymes are inactivated by heat treatment, the cells no longer grow on these substrates but still grow on glucose. medium containing heat-inactivated serum and the appropriate substrate in place of glucose has been successfully used to isolate starch- and ... | 1982 | 7066486 |
| cytotoxicity, mutagenicity and dna damage by hoechst 33342. | hoechst 33342 can be used for flow microfluorimetry (fmf) analysis of the dna content of living chinese hamster cells, giving good resolution (coefficients of variation (cvs) 6%) with relatively nontoxic staining regimens. the dye is, however, a very efficient inhibitor of dna synthesis, with a marked depression of the dna synthetic rate for v79 cells observed at concentrations tenfold less than those required for optimal fmf resolution. nontoxic and minimally toxic hoechst concentrations also r ... | 1982 | 7061816 |
| mutagenicity testing on non-selectively cloned chinese hamster ovary cells with the protein-mapping method. | chemical mutagenesis was studied on chinese hamster ovary cells by protein mapping. cell cultures were treated with methylnitrosourea and the cells were cloned in non-selective media. the proteins of single clones were separated by 2-dimensional electrophoresis and analysed for qualitative (electrophoretic mobility) and quantitative (staining intensity; presence/absence) changes in the protein patterns. the investigation included 26 clones derived from treated cells and 26 control clones. the to ... | 1982 | 7057799 |
| isolation and properties of chinese hamster lung cells resistant to ellipticine derivatives. | chinese hamster lung cells resistant to 9-oh-ellipticine (9-oh-e) were selected in vitro by adding stepwise increasing drug concentrations to the cell growth medium. this selection procedure resulted in the isolation of two sublines, about tenfold and 12-fold resistant to 9-oh-e. this level of resistance did not increase even after about 30 months of drug exposure. cytogenetic studies revealed that the resistant cells carry several discrete karyotype modifications, the most striking being the ab ... | 1982 | 7055817 |
| appearance of crystalloid endoplasmic reticulum in compactin-resistant chinese hamster cells with a 500-fold increase in 3-hydroxy-3-methylglutaryl-coenzyme a reductase. | we have developed a line of chinese hamster ovary cells with a 500-fold increase in 3-hydroxy-3-methylglutaryl-coenzyme a reductase, the membrane-bound enzyme that controls cholesterol synthesis. this line, designated (ut-1, was obtained by stepwise adaptation of cells to growth in increasing concentrations of compactin, a competitive inhibitor of reductase. reductase accounts for approximately 2% of total cell protein in ut-1 cells, as calculated from enzyme specific activity and by immunopreci ... | 1982 | 6951166 |
| multistep origin of tumor-forming ability in chinese hamster embryo fibroblast cells. | twenty-one anchorage-independent subclones and ten subclones with reduced serum requirements were isolated as single-step mutants spontaneously or after ethylmethanesulfonate or n-methyl-n'-nitro-n-nitrosoguanidine mutagenesis of chef/18 diploid chinese hamster embryo fibroblasts. anchorage-independent mutants retain the high serum requirement and nontransformed morphology typical of chef/18. only four of 21 anchorage mutants have spontaneously produced tumors when injected at 10(7)/site in nude ... | 1982 | 6799186 |
| esr studies of o2 uptake by chinese hamster ovary cells during the cell cycle. | magnetic interactions between dissolved oxygen and nitroxide radical spin probes lead to broadening of the esr lines. we have used a closed-chamber method based on this property to determine the maximum rate of o2 uptake per cell (vmax per cell) in cultured mammalian cells. a suitable spin probe and a cell suspension are mixed in an aerated medium, and the rate of disappearance of dissolved o2 is measured. the effects of temperature, ph, and microwave power on the determination of dissolved oxyg ... | 1982 | 6280170 |
| the action spectrum (313-435 nm) for killing hoechst 33258 treated chinese hamster ovary cells containing bromodeoxyuridine substituted dna. | 1982 | 6175004 | |
| emetine resistance in chinese hamster ovary cells is associated with an altered ribosomal protein s14 mrna. | chinese hamster ovary cell mutants resistant to the translational inhibitor emetine (emt b mutants) express a single genetically altered 40s ribosomal subunit protein, s14. that appears to account for their drug resistance. to determine whether emt b mutation affect the structural gene for the s14 protein, we isolated mrnas from several wild-type and emt b mutant clones. we translated the mrnas in a cell-free system derived from wheat germ, and we discerned the biosynthesis of 59 ribosomal prote ... | 1982 | 6122207 |
| the effect of cessation of growth on protein synthesis in a mutant of chinese hamster ovary cells with a temperature-sensitive leucyl-trna synthetase. | a temperature-sensitive mutant of chinese hamster ovary cells with an altered leucyl-trna synthetase fails to grow and to incorporate amino acids into protein properly at or near the non-permissive temperature. this mutant was used to determine whether cessation of growth at the elevated temperature affected elongation factor ef-1, since the activity of ef-1 is markedly lower in non-growing cells in stationary phase than in rapidly-growing cells in exponential phase. cell-free extracts prepared ... | 1982 | 7082671 |
| podophyllotoxin-resistant mutants of chinese hamster ovary cells. alteration in a microtubule-associated protein. | 1982 | 7054166 | |
| distribution of the core histones h2a.h2b.h3 and h4 during cell replication. | the distribution of newly synthesized core histones h2a, h2b, h3 and h4 relative to the dna strand synthesized in the same generation has been examined in replicating chinese hamster ovary cells. cells are grown for one generation in [14c]-lysine and thymidine, and then for one generation in [3h]-lysine and 5-bromodeoxyuridine (brudrib) and a further generation in unlabeled lysine and thymidine. this protocol produces equal amounts of unifilarly substituted and unsubstituted dna. monomer nucleos ... | 1982 | 7063413 |
| regulation of de novo purine biosynthesis in chinese hamster cells. | regulation of de novo purine biosynthesis was examined in two chinese hamster cell lines, cho and v79. de novo purine biosynthesis is inhibited at low concentrations of adenine. the mechanism of inhibition was studied using the rna and protein synthesis inhibitors actinomycin d, cycloheximide, and azacytidine. although all three inhibitors rapidly inhibited de novo purine biosynthesis in vivo, neither adenine nor the rna and protein synthesis inhibitors could be found to have an effect in vitro ... | 1982 | 6171568 |
| isolation and characterization of a mammalian cell mutant defective in 3-hydroxy-3-methylglutaryl coenzyme a synthase. | a somatic cell mutant of the chinese hamster ovary (cho)-k1 cell auxotrophic for mevalonic acid has been isolated by means of the bromodeoxyuridine-visible light technique. this mutant can incorporate labeled mevalonate but not labeled acetate into cholesterol and, thus, is apparently defective in mevalonate biosynthesis. the mutant is recessive with respect to the parental cell phenotype. assessment of the in vitro activities of the enzymes responsible for mevalonate biosynthesis under varying ... | 1982 | 6118375 |
| induced thermal tolerance and heat shock protein synthesis in chinese hamster ovary cells. | we have performed experiments to determine the kinetics of induction of thermal tolerance in chinese hamster ha-1 cells, and the effects of heat treatments on the recovery of protein synthesis, with particular attention to whether heat induces specific proteins, perhaps the heat shock proteins (hsp). the kinetics of the development of thermal tolerance were measured by increases in cellular survival. in parallel experiments, the effects of heat treatment on the recovery of protein synthesis in h ... | 1982 | 7199521 |
| the effect of chronic and acute heat conditioning on the development of thermal tolerance. | survival studies with chinese hamster ovary cells showed that thermal tolerance, which developed during chronic heating (treatment times greater than or equal to 1 hr) or after acute heating (treatment times less than 1 hr) involves similar mechanisms. for example, cells that expressed thermal tolerance during a 6-14 hr chronic heat treatment at 41.5 degrees c or 42 degrees c also expressed thermal tolerance to a subsequent acute treatment at 45.5 degrees c. also, cells heated acutely for 10 min ... | 1982 | 7199520 |
| effects of cytosine arabinoside and daunorubicin on survival and cell cycle progression of chinese hamster ovary cells. | kinetic and cytotoxic effects of cytosine arabinoside (ara-c) and daunorubicin (dnr) on exponentially growing chinese hamster ovary (cho) cells were measured by flow cytometry and by a colony-forming assay, respectively. with ara-c alone, increasing drug concentrations between 10(-7) m and 10(-4) m, for up to 27 hr, were associated with increased inhibition of cell progression through the s phase. even at the very toxic concentration of 10(-4) m, however, cells were able to enter and progress sl ... | 1982 | 7199386 |
| can 3h-uridine-induced sister chromatid exchange be used as a measure of transcriptional activity of chromosomes? | in order to test the validity of using 3h-uridine-induced chromosome damage as a measure of the transcriptional activity of chromosomes, experiments were performed to examine the mechanism by which 3h-uridine induces sister chromatid exchanges. don and b14faf28 chinese hamster cells exposed to 3h-uridine showed a dose-dependent increase in sce frequency, whereas unlabelled uridine produced no increase. 3h-uridine labelling in the presence of increasing concentrations of unlabelled uridine elimin ... | 1982 | 7182126 |
| establishment of chinese hamster stocks homozygous for a reciprocal translocation originally induced by testicular x-irradiation. | following testicular x-irradiation of chinese hamster (cricetulus griseus) males eight progeny (five males and three females) with reciprocal translocatons (heterozygotes) were obtained. they were all phenotypically normal but semi-sterile. homozygotes were produced successfully with chat3 (2p-;9q+) and chat5 (2q-;8q+). they were proven to be fertile. thus, two homozygous stocks with distinct marker chromosomes were established. chat3 homozygotes have shown a high incidence of diabetes, while ch ... | 1982 | 7172765 |
| analysis of chromosome positions in the interphase nucleus of chinese hamster cells by laser-uv-microirradiation experiments. | 1982 | 7169211 | |
| inducible nature of tolerance to lesions produced by ultraviolet light in dna of chinese hamster v79 cells. | chinese hamster v79 cells irradiated by split doses of ultraviolet light (2.5 + 5.0 j m-2) synthesize higher molecular weight dna molecules than those irradiated by a single dose (5.0 or 7.5 j m-2). a second dose applied 8 h following the first one results in a higher portion of higher molecular weight molecules both in relative and absolute terms. molecular weight of dna pulse-labeled 8 h after a dose of 2.5 j m-2 is moderately higher than that of pulse-labeled dna in unirradiated cells, even a ... | 1982 | 7162545 |
| effect of selection cell density on the recovery of mutagen-induced 6-thioguanine-resistant cells (cho/hgprt system). | the relationship between the cell density utilized in the selection for 6-thioguanine-resistant mutants induced by ethyl methanesulfonate and the recovery of mutant colonies was determined in chinese hamster ovary cells. after an adequate phenotypic expression time of 9 days post mutagen treatment, cultures were plated in selection medium at cell densities ranging from 5 x 10(4) to 2 x 10(6) cells/100 mm dish (0.9 to 36.0 x 10(3) cells/cm2). a decline in the frequency of mutant colonies was obse ... | 1982 | 7160342 |
| further studies on the nature of the biphasic radiation survival response of chinese hamster cells v-79-753b to molecular oxygen. | 1982 | 7158516 | |
| comparative genotoxicity studies of ethyl carbamate and related chemicals: further support for vinyl carbamate as a proximate carcinogenic metabolite. | in vivo and/or in vitro mammalian cell systems were used to evaluate sister chromatid exchange (sce) induction and gene mutagenesis effects following exposure to ethyl carbamate (urethane), vinyl carbamate, ethyl n-hydroxycarbamate, and 2-hydroxyethyl carbamate. although ethyl carbamate caused dose-dependent increases in sce when injected into mice, it was ineffective for inducing sce and gene mutation (6-thio-guanine resistance) in chinese hamster v-79 cells cultured with or without the additio ... | 1982 | 7151257 |
| alkylarylnitrosoureas--stability in aqueous solution, partition coefficient, alkylating activity and its relationship to sce induction in chinese hamster v 79-e cells. | the alkylating activity, chemical stability in aqueous solution (ph 7.0; 37 degrees c), and partition coefficient (octanol/water) of the following compounds were determined: 1-methyl-3-phenyl-1-nitrosourea (mpnu), 1-ethyl-3-phenyl-1-nitrosourea (epnu), 1-isopropyl-3-phenyl-1-nitrosourea (i-prpnu), 1-methyl-3-(p-fluorophenyl)-1-nitrosourea (f-mpnu), 1-methyl-3-(p-chlorophenyl)-1-nitrosourea (cl-mpnu), 1-methyl-3-(p-bromophenyl)-1-nitrosourea (br-mpnu), 1,3-dimethyl-3-phenyl-1-nitrosourea (dmpnu), ... | 1982 | 7149911 |
| sister chromatid exchanges in chinese hamster cells treated with seventeen organophosphorus compounds in the presence of a metabolic activation system. | 1982 | 7140680 | |
| mutagenic response to ultraviolet light and x-rays at five independent genetic loci in chinese hamster ovary cells. | the mutagenic response to ultraviolet light and x-irradiation at a number of well characterized independent genetic loci, viz those conferring resistance to 6-thioguanine, ouabain, emetine, methylglyoxal (bis) guanylhydrazone (mgbg), and 5, 6-dichlororibofuranosyl benzimidazole (drb), has been determined. upon exposure of cells to uv light in the range of 70 to 180 ergs/mm2, the frequency of mutants at all of the above genetic loci increased in a linear dose-dependent manner. however, some genet ... | 1982 | 7140673 |
| elimination of metabolic cooperation is associated with the tumor promoters, oleic acid and anthralin. | inhibition of intercellular communication, as measured by metabolic cooperation between 6-thioguanine-sensitive and resistant chinese hamster v79 cells, has been previously shown to be correlated with a large variety of known tumor promoters in many species and organ systems. the effects of anthralin and oleic acid, at non-cytotoxic concentrations, were shown to eliminate metabolic cooperation in chinese hamster cells. moreover, increased serum levels appear to reduce the effectiveness of 12-o-t ... | 1982 | 7139869 |
| chromosome localization of the genes for isocitrate dehydrogenase-1, isocitrate dehydrogenase-2, glutathione reductase, and phosphoglycerate kinase-1 in the american mink (mustela vison). | twenty-eight hybrid clones with different mink chromosomes were derived from the fusion of chinese hamster and american mink (mustela vison) cells. this set of clones made it possible to assign the mink genes for isocitrate dehydrogenase-1 (soluble) to chromosome 4, for isocitrate dehydrogenase-2 (mitochrondrial) to chromosome 10, for glutathione reductase to chromosome 6, and for phosphoglycerate kinase-1 to the x chromosome. | 1982 | 7128216 |
| chromosomal aberrations in chinese hamster cells exposed in vitro to tritium-labelled thymidine or x-rays at--196 degrees c. | a comparison was made between the incidence of chromosomal aberrations in g2-phase first division chinese hamster cells exposed to tritium labelled thymidine (dose range 54-522 rad) or to 250 kv x-rays (dose range 98-711 rad) at--196 degrees c. the dose-response relationship for chromatid aberrations, expressed as breaks per cell, appeared to be linear for intranuclear tritium whereas that for x-rays was curvilinear. for the dose range studied, cells exposed to x-rays were markedly less sensitiv ... | 1982 | 7128208 |
| isolation, purification and partial characterization of galactokinase from chinese hamster liver. | 1. galactokinase was purified from chinese hamster liver. the purification process consisted of an initial biphasic partition separation followed by column chromatography on deae-cellulose. deae-sephadex, sephacryl s-200 and hydroxyapatite. 2. the enzyme was stabilized during the purification procedure by the inclusion of 10% glycerol, 1 mm phosphate and 20 mm beta-mercaptoethanol in all the buffer solutions. 3. chromatography on hydroxyapatite separated two forms of galactokinase, one of which ... | 1982 | 7117670 |
| cytotoxic and mutagenic properties of shale oil byproducts ii. comparison of mutagenic effects at five genetic markers induced by retort process water plus near ultraviolet light in chinese hamster ovary cells. | a chinese hamster ovary (cho) cell line heterozygous at the adenine phosphoribosyl transferase (aprt) locus was used for selection of induced mutants resistant to 8-azaadenine (8aa), 6-thioguanine (6tg), ouabain (oua), emetine (emt) and diphtheria toxin (dip). the expression times necessary for optimizing the number of mutants recovered at the different loci have been determined using the know direct acting mutagen, far ultraviolet light (fuv), and a complex aqueous organic mixture (shale oil pr ... | 1982 | 7117215 |
| evidence that sister chromatid exchanges and chromatid breaks are two independent events. | the relative frequencies of sister chromatid exchanges (sce) and chromatid breaks in brdu (5-bromodeoxyuridine) - sensitive site (lq22 leads to lq23) in chinese hamster cells after brdu incorporation were studied. the results show that chromatid breaks do not follow the "exchange hypothesis" and provide evidence that chromatid breaks and sces are two independent events despite some common features. | 1982 | 7117032 |