PMID(sorted ascending)
localization of neurotensin-immunoreactive cells in the small intestine of man and various mammals.antibodies against synthetic bovine neurotensin were raised in rabbits and used to demonstrate neurotensin-immunreactive cells by immunohistochemical methods. in the jejunum and ileum of all species investigated (man, dog, monkey, cat, rabbit, sheep, rat, mouse, hamster, chinese hamster, gerbil, pig and guinea pig) cells were present in the mucosa, which reacted specifically with antineurotensin serum using the indirect immunofluorescence and peroxidase-antiperoxidase methods. in the monkey tupa ...1977409699
retention of the glycocalyx after cell detachment by egta.chinese hamster ovary cells were examined ultrastructurally following several detachment procedures. alterations in the surface glycoproteins were observed by using ruthenium red in the fixation procedure. trypsin removed a major portion of the cells glycocalyx and formed spherical cellular configurations. egta detached cells were also spherical, however, their glycocalyx appeared to remain although redistributed over the cell surface. kinetic studies showed no alterations in subsequent populati ...1977411829
pesticide induced ouabain resistant mutants in chinese hamster v79 cells.the effect of 3 insecticides (chlordane, dieldrin and carbaryl) and one herbicide (2,4-d-fluid) was studied on the induction of ouabain-resistant mutants in chinese hamster v79 cells at concentrations approaching the environmental protection agency (epa) tolerance limits. the kinetics and dose range for cytotoxicity were determined by colony formation assay. results showed that these compounds enhanced the number of ouabain-resistant mutants and acted as weak mutagens.1977413633
characterization of residual hexosaminidase activity in sandhoff's disease using man-chinese hamster cell obtain information about the nature of the residual hexosaminidase activity in sandhoff's disease, hybrid cell lines between fibroblasts from a patient with sandhoff's disease and chinese hamster cells were isolated. in these hybrid cell lines, a heteropolymeric isoenzyme was detected that is composed of human alpha- and chinese hamster hexosaminidase subunits. due to the electrophoretic and immunological behavior of the heteropolymeric molecules in interspecies hybrids with normal fibroblast ...1977413781
regional localization of a beta-galactosidase locus on human chromosome 22.human white blood cells with an x/22 translocation [46, xx, t(x;22)(q23;q13)] were fused with chinese hamster cells. the isolated hybrids were analyzed for human chromosomes and 21 enzyme markers. an electrophoretic technique for studying the beta-galactosidase isoenzymes in man-chinese hamster hybrid cells was developed. immunological studies showed that the beta-galactosidase marker studied in these hybrids did contain immunological determinants of human origin. furthermore the results provide ...1977414365
determination of corynebacterium diphtheriae toxigenicity by a colorimetric tissue culture assay.chinese hamster ovary (cho) cell cultures in microtiter wells are sensitive to growth inhibition and killing by picogram quantities of diphtheria toxin. in the absence of biologically active toxin, the cho cell culture produces sufficient acidic metabolites to change the phenol red ph indicator from pink to yellow within 56 h. in the presence of 10 pg of toxin per well, growth inhibition can be observed microscopically within 24 h. diphtheria toxin can be qualitatively assayed from culture super ...1978415068
reduction of beta-galactosidase in the ketotic chinese hamster kidney.kidneys from normal, diabetic-nonketotic and ketotic chinese hamsters were homogenized, fractionated and assayed for beta-glucosidase, and beta-galactosidase activities. the kidneys of the ketotic animals were enlarged but the protein content in each subcellular fraction was similar in all three groups of animals. beta-glucosidase was found chiefly in the soluble fraction and no difference was observed in these animals. beta-galactosidase was distributed in both cytoplasmic and particulate fract ...1978417989
neurogenesis in the amygdaloid nuclear complex in a rodent (the chinese hamster). 1979421144
the effect of amino acids on the temperature sensitive phenotype of the mammalian leucyl-trna synthetase mutant tshl and its revertants.the temperature sensitive leucyl-trna synthetase mutant tshl and two revertants have been compared to the parental chinese hamster ovary cells with respect to the effects of amino acid concentrations in the medium on growth. elevating the leucine concentration 30- or 100-fold allowed tshl to grow exponentially at 38.5 degrees c, normally the nonpermissive temperature. partial revertants that had recovered some enzyme activity required smaller supplements for growth. measurements of the leucine p ...1979422660
isolation and characterization of revertants of the mammalian temperature sensitive leucyl-trna synthetase mutant tshl.nine spontaneous and seven ethyl methanesulfonate induced revertants of the chinese hamster ovary cell line mutant (tshl), which possesses a temperature sensitive leucyl-trna synthetase, were isolated and characterized with respect to growth rate, leucyl-trna synthetase activity and thermolability, intracellular leucine pool size, and rrna content. although most revertants had increased leucyl-trna synthetase activity, and of those tested, all but one had increased thermostability, each appears ...1973422661
selective toxicity of 6-hydroxydopa for melanoma cells.the growth inhibitory effect of 6-hydroxydopa, a cytotoxic analog of l-dopa, was studied in melanotic and amelanotic cloudman melanoma, mouse fibroblast l929 and chinese hamster ovary cells. a marked sensitivity of pigmented cells to 6-hydroxydopa was observed with a 10-fold increase in sensitivity of pigmented cells. sensitivity correlated with the capacity of cells to incorporate radiolabeled exogenous l-dopa. the drug affected primarily dna and rna synthesis with greater inhibition observed i ...1979422870
mutagenic activities of 1,2,7,8-diepoxyoctane in chinese hamster lung cells.the mutagenicity of 1,2,7,8-diepoxyoctane (deo) was investigated using chinese hamster lung cells. 6-thioguanine resistance and chromosome aberrations were used as markers for mutagenicity testing. deo was found to be genetically active and to readily from adducts with radiolabeled nucleotides, as demonstrated through thin-layer chromatography in deo/nucleotide mixtures. continuous disappearance of cells carrying chromosome aberrations from the cell populations was observed. based on the expecte ...2013422925
mutagenicity and carcinogenicity of n-methyl-n'-nitro-n-nitrosoguanidine i. induction of chromosome aberrations and mitotic anomalies in chinese hamster ovary cells.cultured chinese hamster ovary (cho) cells were exposed to different concentrations of n-methyl-n'-nitro-n-nitrosoguanidine (mnng) for either 24 hr or 6 days. for cytological consequences of mnng exposure, cho cells were treated for 24 hr and allowed a 24 hr recovery period prior to analysis; for the estimation of cytotoxicity of mnng, cells were treated for 6 days followed by a 6 day recovery period. the cytotoxic effect of mnng based on the colony-forming ability of treated cells showed a semi ...1973422929
chromosomal aberrations of don lung cells of chinese hamster after exposure to vinblastine in vitro. 1979423909
synthesis of low molecular weight rna components a, c and d by polymerase ii in alpha-amanitin-resistant hamster an attempt to establish which rna polymerase catalyzes the synthesis of the low molecular weight rna components a, c and d, ama 1 cells (mutant chinese hamster cells) were used in experiments with addition of alpha-amanitin. ama 1 cells contain an altered rna polymerase ii which is 800 times more resistant towards inhibition by alpha-amanitin than the wild type enzyme. alpha-amanitin (up to 200 microgram/ml) added to these cells does not affect the synthesis of the low molecular weight rnas a ...1979424295
circular dichroic and sedimentation studies of phosphorylated h1 from chinese hamster cells. 1979427101
[effect of the inhibition of a synthesis processes in the s-period on the subsequent course of mitosis in a synchronized chinese hamster cell culture].the transcription of all nuclear rna and rrna was inhibited in the synchronized chinese hamster cell culture by actinomycin d and protein synthesis was suppressed by pyromycin during the first and the second parts of the s period of the mitotic cycle. a decrease of the mitotic cell activity was revealed during the first and second waves of cell proliferation after the synchronization irrespective of the time of the antibiotic administration. at the same time there was noticed an increase of such ...1979427282
excision repair of cis-diamminedichloroplatinum(ii)-induced damage to dna of chinese hamster cells.platinum was lost from the dna of cis-diamminedichloroplatinum(ii) [cis-pt(ii)]-treated exponentially growing chinese hamster v79-379a cells with a half-life of 28 hr. by contrast, platinum was lost from the dna of cells treated in stationary-phase culture with a half-life of 4 days. cells treated in and allowed to remain as a stationary-phase culture maintained an intact and apparently viable appearance. when the stationary-phase culture was diluted with fresh medium, cell division occurred, an ...1979427811
the in vitro and in vivo reaction at the n7-position of guanine of the ultimate carcinogen derived from benzolalpyrene.the previously reported reaction at n2- and n7- of guanine following addition of 7 alpha,8 beta-dihydroxy-9 beta, 10 beta-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (anti-bpde) to an aqueous solution of dna has been studied in more detail. the extent of reaction and the relative yields of n2- and n7-products was measured over the range of ph 4--7. the depurination following reaction at the n7-position of guanine was found to have a half-life of 3 h. reaction of the isomeric 7 alpha,8 beta-dihydroxy ...1979428016
transcription and hybridization of 125i-crna from flow sorted chromosomes.metaphase chromosomes from the chinese hamster cell line m3-1 were separated by means of a flow sorter. two chromosome fractions were used for this study: a, which consisted of 95% pure chromosome no. 1, and b, which was 90% pure chromosome no. 2. the dna of 10(6) chromosomes of each type was purified, and a 125i-crna transcript was synthesized in a reaction containing e. coli rna polymerase and carrier-free 125i-ctp (1.7 ci/mumole). the crna product synthesized with template dna from 10(5) sort ...1979428270
[vaginal smear cycle in 4-day cyclic chinese hamsters, cricetulus griseus].the contents of vaginal smear of 4-day cyclic chinese hamster (cricetulus griseus) was investigated every 3 hours for 5 days. a light-dark cycle of 14--10 hr was used with the lights turned on at 6 : 00 a.m. estrous cycle of the chinese hamster determined by vaginal smears can be divided into 6 periods. the proestrous phase started at about 0 : 00 of day 1, the day of the proestrous phase was designated as day 1 of the estrous cycle. in the afternoon of the same day 1, nucleated epithelial cells ...1979428430
visualization of the interphase chromosomes of ornithogalum virens and muntiacus muntjak.a technique for visualizing "interphase chromosomes" was applied to nuclei of the angio-spermous plant, ornithogalum virens (2 n = 6), and the male mammal, muntiacus munjak (2 n = 7), in an attempt to correlate the numbers of "chromosomes" visible during interphase with the respective diploid chromosome numbers. the alterations in chromosome structure observed during g1, s, and g2 periods were comparable to those previously reported in allium cepa and chinese hamster (cho line) cells [33], but f ...1979428620
effects of various cyclophosphamide concentrations in vivo on sister chromatid exchanges (sce) and chromosome aberrations of chinese hamster bone marrow cells: comparison of two methods measuring the mutagenicity of a test compound.the in vivo sce formation and the induction of chromosome aberrations in the bone marrow of chinese hamsters (cricetulus griseus) were studied after various concentrations of cyclophosphamide, and the sensitivity of the two test methods was compared. the administraiton of 1.0, 5.0, 13.3, 25.0, and 40.0 mg/kg body weight induced a dose-dependent increase in sce. the frequency of chromosome aberration, however, was not increased significantly with doses of 1.0 and 5.0 mg/kg body weight. only with ...1974429007
purine and pyrimidine transport and phosphoribosylation and their interaction in overall uptake by cultured mammalian cells. a re-evaluation.the zero-trans uptake of purines and pyrimidines was measured in suspensions of novikoff rat hepatoma, mouse l, p388 mouse leukemia, and chinese hamster ovary cells by a rapid kinetic technique which allows the determination of uptake time points in intervals as short as 1.5 s. kinetic parameters for purine/pyrimidine transport were determined by measuring substrate influx into cells in which substrate conversion to nucleotides was negligible either due to lack of the appropriate enzymes or to d ...1979429288
ribosomal transcriptional complexes in subnuclear fractions of chinese hamster ovary cells after short-term actinomycin d treatment. 1979430587
failure of caffeine to influence induced mutation frequencies and the independence of cell killing and mutation induction in v79 chinese hamster cells.using v79 chinese hamster cells and a replating assay, no effect of caffeine post-treatment on spontaneous or uv- or ems-induced mutation frequencies to 8-azaguanine resistance was demonstrable. however, considerable potentiation of cell killing was observed. previous reports that caffeine enhances induced mutation frequencies are explained by an artefact in the situ method used; a similar artefact may also explain the cumulative in situ mutation dose-response curves. furthermore, the relationsh ...1979431556
mutagenesis of chinese hamster cells is facilitated by thymidine and deoxycytidine. 1979431725
identification of a mouse gene required for binding of rauscher mulv envelope gp70.mouse chromosome segregating somatic cell hybrids were established between a mouse thymic leukemai cell line (grsl) and chinese hamster e36 cells. the grsl cells specifically bound purified rauscher leukemia virus gp70 while the e36 cells exhibited no binding. the hybrids selectively bound ruascher gp70 depending on the presence of a mouse cellular gene for the ecotropic murine luekemia gp70 receptor. a syntenic relationship was observed between the dip-3 chromosome marker (on chromosome 5) and ...1979432756
studies on 1-beta-d-arabinofuranosyl cytosine-resistant mutants of chinese hamster fibroblasts: iii. joint resistance to arabinofuranosyl cytosine and to excess thymidine--a semidominant manifestation of deoxycytidine triphosphate pool expansion.variants isolated from mutagenized chinese hamster fibroblasts by a single cycle of exposure to ara-c distributed into two classes: (1) deoxycytidine (dc) kinase deficient clones with a high level of resistance, this phenotype was recessive in hybrids; and (2) clones exhibiting joint resistance to thymidine (dt) and to "low" ara-c concentration, this phenotype was accounted for by an increased dctp pool. the incorporation of exogenous dc into macromolecules was markedly altered in these variants ...1979432758
isolation of hydroxyurea-resistant cho cells with altered levels of ribonucleotide reductase.a chinese hamster ovary cell line selected for resistance to hydroxyurea was serially cultivated in the absence of a selective agent, and cells with decreased resistance to the cytotoxic effects of hydroxyurea gradually accumulated in the population. three stable subclones with differing drug sensitivities were isolated from this mixed population and were found to contain intracellular levels of drug-sensitive ribonucleotide reductase which correlated with the degree of cellular resistance to hy ...1975432759
a ts mutant isolated from chl cells: inhibition of dna replication at nonpermissive temperature.a mutant chinese hamster cell clone has been isolated from an s phase culture. this clone, ts154, could not replicate dna at nonpermissive temperature (39 degrees c), although it synthesized dna normally at permissive temperature (33 degrees c). after transfer to 39 degrees, ts154 cells replicated dna semiconservatively through precisely two complete rounds and divided twice before they ceased dna synthesis and further growth. the mutation in ts154 affects dna replication specifically, as its ra ...1979432760
quantitation of antibody binding to cell surface antigens by x-ray fluorescence x-ray spectrometric method has been developed to quantitate antibody bindng to whole cell surfaces in order to obtain a distribution of binding within a population of cells. the method involves incubation of target cells with ferritin-labeled antibody. analysis of prepared samples in a modified transmission electron microscope with an x-ray detector and data analysis equipment, yields quantitative results on the binding of labeled antibody to individual cells. the binding of anti-2,4-dinitrop ...1979435491
effect of continuous insulin infusion with an implantable seven-day minipump in the diabetic chinese hamster. 1979436792
regulated synthesis of rna polymerase ii polypeptides in chinese hamster ovary cell lines.rna polymerase ii polypeptides present in [35s]methionine-labeled chinese hamster ovary (cho) cell extracts have been quantitatively immunoprecipitated with an anti-calf thymus rna polymerase ii serum. analyses of the immunoprecipitates on sodium dodecyl sulfate polyacrylamide gels indicated that the immunoprecipitated polymerase ii of both wild type cho cells and the alpha-amanitin-resistant mutant ama1 had polypeptides of molecular weight 214,000, 140,000, 34,000, 25,000, 23,000, 20,500, and 1 ...1979438182
the importance of ornithine as a precursor for proline in mammalian cells.ornithine aminotransferase catalyzes the reversible transamination of l-ornithine to delta1-pyrroline-5-carboxylate, the immediate precursor of proline. the direction and flux through this pathway in mammalian cells has not been established. glutamate has generally been considered to be the most important precursor for proline biosynthesis, but recent studies in xiphoid cartilage indicate that a significant fraction of cellular proline is derived from ornithine. using newly isolated mutant chine ...1979438294
characterization of cell lines showing growth control isolated from both the wild type and a leucyl-trna synthetase mutant of chinese hamster ovary cells.the genetic approach to the problem of cellular growth control is limited by the availability of recessive mutations in cell lines which are capable of growth control in vitro. the cho cell line has yielded many recessive mutations including, for example, tsh1, a temperature sensitive leucyl-trna synthetase mutant, which under non-permissive conditions rapidly shuts down protein synthesis and generates uncharged trna. both cho and tsh1 are transformed, however, and do not respond to environmenta ...1979438301
the effect of hexose on chloramphenicol sensitivity and resistance in chinese hamster cells. 1979438306
cis-platinum(ii) diamine dichloride causes mutation, transformation, and sister-chromatid exchanges in cultured mammalian cells.the anti-tumor agent cis-platinum(ii) diamine dichloride caused dose-dependent toxicity in v79 chinese hamster cells and in secondary syrian hamster embryo cells. chromosome aberrations were induced and positive dose--response relationships were observed for induction of sister-chromatid exchanges and 6-thioguanine-resistant mutations in v79 cells and morphologic transformation of secondary syrian hamster embryo cells. the findings suggest that this chemical is a potential human carcinogen.1979440327
the influence of testicular microanatomy on the potential genetic dose from internally deposited 239pu citrate in chinese hamster, mouse, and man. 1979441246
a study of the repair of potentially lethal and sublethal radiation damage in chinese hamster cells exposed to extremely hypo- or hypertonic nacl solutions. 1979441248
potentially lethal damage versus sublethal damage: independent repair processes in actively growing chinese hamster cells. 1979441249
effects of hyperthermia and x irradiation on sister chromatid exchange (sce) frequency in chinese hamster ovary (cho) cells. 1979441255
differential effect of procaine on irradiated mammalian cells in culture.hela and v-79 chinese hamster cells temporarily stored in ampoules were treated with the local anesthetic procaine. postirradiation treatment increased lethality in hela cells depending on drug concentration, duration of treatment and cell density, as measured by colony-forming ability upon plating. if present during irradiation only, procaine protected from irradiation. in v-79 cells procaine potentiated radiation lethality only in freshly trypsinized cells. procaine effect was thus cell type s ...1979441343
ganglioside composition of malignant and actinomycin d-resistant nonmalignant chinese hamster cells. 1972444244
thymidine transport in cultured mammalian cells. kinetic analysis, temperature dependence and specificity of the transport system.the transport of thymidine has been characterized kinetically and thermodynamically in novikoff rat hepatoma cells grown in culture and, less extensively, in mouse l cells, chinese hamster ovary cells, p388 murine leukemia cells and hela cells. that the characterizations pertained to the transport system per se was ensured, (i) by employing recently developed methods for rapid sampling of cell/substrate mixtures in order to follow isotope movements within a few seconds after initial exposure of ...1979444518
dna fork displacement rates in synchronous aneuploid and diploid mammalian cells.dna fork displacement rates were measured in chinese hamster ovary cells (cho), human hela cells and human diploid fibroblasts. for cho cells two independent techniques were used: one based on cscl equilibrium density gradients and the other on 313 nm photolysis of incorporated bromodeoxyuridine (brdurd). both methods indicated that there was no significant variation in fork displacement rates in cho cells as they progressed through s phase. asynchronous cho cultures displayed the same average v ...1979444527
effects of hyperthermia (41.5 degrees) on chinese hamster ovary cells analyzed in motisis.the mitotic cells from an asynchronous population of chinese hamster ovary cells exposed to 41.5 degrees for 7 hr were examined by light and electron microscopy to determine if there were any morphological abnormalities related to cell death or lengthening of metaphase induced by hyperthermia. all components of the mitotic apparatus were formed during exposure to heat, and the mitotic apparatus was functional as demonstrated by eventual cell division. however, heat caused the nuclear envelope to ...1979445391
induction of thermotolerance by multiple heat fractions in chinese hamster ovary cells. 1979445450
effects of hyperthermia (45 degrees) on macromolecular synthesis in chinese hamster ovary cells. 1979445469
nuclear protein synthesis at permissive and non-permissive temperatures in a chinese hamster ovary cell line with a temperature-sensitive defect in cytoplasmic non-mitochondrial protein synthesis. 1979446528
differential metabolism of mannose by chinese hamster cell lines. 1979446534
cytogenetic properties of chinese hamster v79-e cells: g-banding, c-banding, nucleolar organizer regions, and sister chromatid exchanges.a line of the chinese hamster v79 strain, denominated as v79-e, is cytogenetically characterized. it has a modal chromosome number of 22. chromosome morphology, g- and c-banding reveal strong differences from the normal complement of the chinese hamster presumably caused by rearrangements of chromosome segments during the past 20 years of in vitro culture. 4 chromosomes possess terminal nucleolar organizer regions. spontaneous sister chromatid exchanges occur with a frequency of 0.38 sister chro ...1979446595
effect of continuous low-dose insulin treatment on subsequent incidence of diabetes in genetically prediabetic chinese an attempt to prevent the onset of diabetes, young, genetically prediabetic (but not yet hyperglycemic) chinese hamsters were treated continuously with insulin via minipump for 4 wk beginning 1 wk before the predicted age of onset of glucosuria (age 7 wk). continuous insulin infusion which increased the plasma insulin levels by 70%, did not cause hypoglycemia, nor did it reduce the incidence or severity of diabetic symptoms over the ensuing year of observation. in fact, early treatment with e ...1979446913
analysis of polypeptide turnover rates in chinese hamster ovary cell plasma membranes using two-dimensional electrophoresis. 1979447629
phosphorylation of the 10-nm filament protein from chinese hamster ovary cells. 1979447707
emetine-resistant chinese hamster cells. the identification of an electrophoretically altered protein of the 40 s ribosomal subunit. 1979447708
enhancement of thermal killing by polyamines. iii. synergism between spermine and gamma radiation in hyperthermic chinese hamster cells. 1979451160
the metabolically mediated dna damage and subsequent dna repair by 4-chlorobiphenyl in chinese hamster ovary cells.the metabolism of [3h]-4-chlorobiphenyl (cb) by chinese hamster ovary cell cultures resulted in the formation of lipophilic hydroxylated metabolites, trichloroacetic acid soluble conjugates and covalent macromolecular adducts. the major lipophilic metabolite was chromatographically similar to 4'-chloro-4-biphenylol. the intracellular macromolecules were fractionated into protein, rna and dna. although protein was the major target of covalent interaction with [3h]-cb and contributes 85% of the ma ...1979451338
stages in the prenatal development of the chinese hamster (cricetulus griseus).a system of staging embryos is described for the chinese hamster (cricetulus griseus). this system of staging, based on streeter's developmental horizons in human embryos, comprises three sets of criteria: 1) data on postconceptional age, size and number of somites, 2) external characteristics and 3) internal characteristics. a comparison has been made with data in mouse (theiler, 1972) as well as in primates. it seems that the order of organogenesis, i.e. the sequence in which individual organs ...1979453550
sister chromatid exchanges induced by inhaled anesthetics.there is sufficient evidence that anesthetics may cause cancer to justify a test of their carcinogenic potential. baden, et al., using the ames test, a rapid and inexpensive genetic indicator of carcinogenicity, have shown that among currently used anesthetics fluroxene alone caused bacterial mutations. the authors used the sister chromatid exchange (sce) technique, another rapid assay of mutagenic-carcinogenic potential. the frequency of sister chromatid exchanges in chinese hamster ovary cells ...1979453561
effects of methotrexate on thymidine triphosphate levels in chinese hamster cell cultures. 1979454460
characterization of postribosomal aminoacyl-trna synthetases in cultured chinese hamster ovary cells. 1979454608
association of human chromosome 14 with a ts defect in g1 of chinese hamster k12 cells.somatic cell hybrids between human lymphoblastoid cells (raji) and temperature-sensitive chinese hamster cells (k12) were selected from monolayer cultures in mem at 40 degrees c. a total of 21 hybrid clones were isolated and karyotyped. all clones contained a near complete set of chinese hamster chromosomes and 1 to 5 human chromosomes. human chromosome 14 present in the hybrid cells of all clones; and was the only human chromosome retained in 10 clones. the presence of human chromosome 14 in hy ...1979455493
higher order structure of chromosomes.isolated chinese hamster metaphase chromosomes were resuspended in 4 m ammonium acetate and spread on a surface of distilled water or 0.15 to 0.5 m ammonium acetate. the dna was released in the form of a regular series of rosettes connected by interrossette dna. the mean length of the rosette dna was 14 micron, similar to the mean length of 10 micron for chromomere dna of drosophila polytene chromosomes. the mean interrosette dna was 4.2 micron. sds gel electrophoresis of the chromosomal nonhist ...1979456198
two-dimensional electrophoretic analysis of concanavalin-a binding components in the plasma membranes of chinese hamster fibroblasts. 1979456578
effect of cell growth rate and dose fractionation on chemically-induced ouabain-resistant mutations in chinese hamster v79 cells.chinese hamster v79 cells were grown in medium containing either 10% or 2% fcs during the expression time following exposure to mnng. the lower serum concentration was used to reduce the rate of cell replication, thereby allowing more time for dna repair prior to "fixation" of the mutagenic lesion. in addition, fractionated and continuous exposures to mnng and mam, respectively, were carried out to determine their effect on the number of induced ouabain-resistant mutants. the results indicated t ...1979460287
induction of sister-chromatid exchanges in human lymphocytes and chinese hamster cells exposed to aflatoxin b1 and n-methyl-n-nitrosourea.the effect of a 1-h exposure to aflatoxin b1 (afb1) in inducing sister-chromatid exchange in chinese hamster ovary (cho) cells and human lymphocytes in the presence or absence of mixed function oxidase ("s9 mix") was compared. cho cells were also exposed to a graded series of doses of n-methyl-n-nitrosourea, a powerful inducer of sce whose action was independent of the presence or absence of s9 mix. cho and human cells showed a close correlation in response to sce induction by afb1 and in both c ...1979460293
the cytotoxic, mutagenic and clastogenic effects of chromium-containing compounds on mammalian cells in culture.examples of chromic and chromate salts have been examined for their effects on a cultured chinese hamster cell line. the responses studied were cytotoxicity, mutagenesis and clastogenesis. chromate (hexavalent chromium) salts of both high and medium water solubility were active in producing all three classes of response, whereas an insoluble chromate salt and a soluble chromic (trivalent chromium) salt were inactive. in addition to illustrating the value of using mammalian cells in culture for s ...1979460294
platinum-induced mutations to 8-azaguanine resistance in chinese hamster ovary cells.6 platinum (pt) compounds were compared in suspension cultured chinese hamster ovary (cho-s) cells with respect to their inhibition of growth, their reduction of cloning efficiency, and their induction of mutants resistant to 200 microm (30 micrograms/ml) 8-azaguanine (8-ag) and 3 mm ouabain (oua), respectively. the toxicity of these compounds can be ranked by the medium concentrations which decrease suspension growth/or cloning efficiency by 50%: cis-pt(nh3)2-cl2 (0.9/1.5 microm) greater than p ...1979460295
cytotoxic effects of procaine, lignocaine and bupivacaine.cytotoxic effects of procaine, lignocaine and bupivacaine were investigated on cultures of chinese hamster lung fibroblasts. cell growth was inhibited over 24 h exposures with an ed50 of 0.17% for procaine, 0.07% for lignocaine and 0.02% for bupivacaine. cell survival (measured as colony-forming ability) was reduced over 24 h exposure with an ed50 of 0.21% for procaine, 0.09% for lignocaine and 0.06% for bupivacaine. morphological changes included vacuolation, cell rounding and retraction from t ...1979465252
dependence of mammalian dna replication on dna supercoiling. i. effects of ethidium bromide on dna synthesis in permeable chinese hamster ovary cells.chinese hamster ovary cells labelled with [14c]thymidine were made permeable, incubated with various concentrations of the intercalating dye ethidium bromide, and centrifuged through neutral sucrose gradients. the gradient profiles of these cells were qualitatively similar to those obtained by centrifuging dna from untreated, lysed permeable cells through gradients containing ethidium bromide. the sedimentation distance of dna had a biphasic dependence on the concentration of ethidium bromide, s ...1979465491
dependence of mammalian dna replication on dna supercoiling. ii. effects of novobiocin on dna synthesis in chinese hamster ovary cells.novobiocin, an inhibitor of gyrase-induced dna supercoiling and dna replication in prokaryotes, inhibited the incorporation of dna precursors into dna in both intact and permeable chinese hamster ovary cells; much higher concentrations were required for permeable cells, in which no new replicons were initiated. nucleoids were prepared from cells that were incubated for 60 min with 200 micrograms/ml novobiocin, made permeable, and incubated with 0--50 micrograms/ml ethidium bromide. sedimentation ...1979465492
[pathology of mitosis after cellular recovery from a metaphase block].the experiments in chinese hamster fibroblast-like cells have shown that the c-mitosis inducing agents (colchicine, colcemid and low temperature) produce evident stathmokinetic and radiomimetic effects. by the reversibility moment of the former the latter becomes apparent, manifesting in bridge accumulation. this form of pathology is likely to be caused by the disturbance of the cellular nucleoprotein metabolism in c-mitosis.1979465693
oer and rbe for negative pion beams of different peak widths.experimental data on survival curves for pion because of different peak widths under aerobic and hypoxic conditions are reported. metabolic depletion of oxygen by the chinese hamster cells (line v79) was used to obtain hypoxia. the results indicate that the rbe at the beam entrance (plateau) is approximately 1.0. when the bragg peaks were broadened to widths of 1.3, 7.8, and 10.5 cm (at the 80% dose level), the rbe (50% cell survival) at the peak centres was 1.7, 1.6, and 1.2, respectively. the ...1979465928
the excision of n-methyl-n-nitrosourea-induced lesions from the dna of chinese hamster cells as measured by the loss of sites sensitive to an enzyme extract that excises 3-methylpurines but not enzyme extract from micrococcus luteus excises 3-methyladenine and 3-methylguanine but not o6-methylguanine, 7-methylguanine, 1-methyladenine or 7-methyladenine from dna reacted with n-methyl-n-nitrosourea. the extract was used to detect lesions in the dna of chinese hamster cells treated in culture with n-methyl-n-nitrosourea. it was concluded that 3-methyladenine is excised from these cells with a half-life of about 2.3 h.1979467426
mutagenicity of quercetin and kaempferol on cultured mammalian cells.mutagenic activity of quercetin and kaempferol on v79 chinese hamster cells was investigated. quercetin was proved to have mutagenicity not only by metabolic activation system using rat liver microsomes, but also by direct application method. kaempferol was mutagenic by metabolic activation system, but its activity by direct method seemed very low. these data suggest that the tested flavonoids seem to be metabolized for exerting their mutagenic activity and v79 cells themselves have an enzymic a ...1979467892
transformed cells have lost control of ribosome number through their growth cycle.previous studies on the synthesis and function of the protein synthetic machinery through the growth cycle of normal cultured hamster embryo fibroblasts (ha) were extended here to a series of four different clonal lines of polyoma virus-transformed ha cells. under our culture conditions, these transformed cells could enter a stationary phase characterized by no mitotic cells, very low rates of dna synthesis, and arrest in a post-mitotic pre-dna synthetic state. cellular viability was initially h ...1979468917
characteristics of concanavalin a-resistant chinese hamster ovary cells and certain revertants.clones of chinese hamster ovary (cho) cells were isolated by single-step selection for resistance to killing concanavalin a (cona) and certain cellular and membrane properties were examined. the cona-resistant isolates were only about 2-fold more resistant than wild type cells to the selecting lectin, but exhibited pleiotropic temperature-sensitivity for growth, markedly altered morphology and adherence, and significant difference in susceptibility to other agents such as colchicine. two reverta ...1979468920
mutagenicity of vinyl chloride, vinylidene chloride and chloroprene in v79 chinese hamster cells.the mutagenicity of vinyl chloride, vinylidene chloride (1,1-dichloroethylene) and chloroprene (2-chloro-1,3-butadiene) was tested in v79 chinese hamster cells in the presence of a 15 000 x g liver supernatant from phenobarbitone-pre-treated rats and mice. mutations in terms of 8-azaguanine and ouabain resistance were induced in a dose-related fasion by exposure to vapour of vinyl chloride in the presence of liver supernatant from phenobarbitone-pretreated rats. vapours of vinylidene chloride an ...1979470972
microspectrofluorometric analysis of surface antigens of murine melanoma and hamster peritoneal cell hybrids: comparisons of species antigenicity, chromosome number, and tumorigenicity.somatic cell hybrids from viral fusions of murine melanoma (pazg) x chinese hamster peritoneal cells (ch) were compared with respect to surface antigenicity, karyotype and tumorigenicity. one line, f57-(9), which arose from the hybridization of two ch cells and one pazg cell, had slight (6%) ch chromosome loss but 80%pazg chromosome loss after 10 months in culture. these cells expressed ch antigens strongly and pazg antigens weakly. in comparison, another hybrid, f57-(7), formed from one ch and ...1979471422
combined effects of x irradiation and hyperthermia (42 and 44 degrees c) on chinese hamster v-79 cells in vitro. 1979472127
synergistic biological effects of ultrasound and ionizing radiations evaluated in vitro.the effects of diagnostic ultrasound on growing asynchronous cultures of chinese hamster ovarian cells were evaluated, with particular attention to possible synergism with ionizing radiations. measurements of cellular growth rate/survival and changes in morphology indicated that synergistic biological effects were absent.1979472256
the influence of ethanol treatment of cytogenetic effects in bone marrow cells of chinese hamsters by cyclophosphamide, aflatoxin b1 and patulin.chromosomes were investigated from the bone marrow of chinese hamsters which received 10% (v/v) ethanol as the only liquid supply for a period of 9 weeks. at the end of the ethanol drinking period 1 group of animals received 2 oral doses of 80 mg/kg cyclophosphamide (cp), a second group received 2 oral doses of 25 mg/kg aflatoxin b1 (afb1), a third group 2 oral doses of 20 mg/kg patulin (pa). the 2 applications were separated by 24 h. the intake of ethanol had no effect on the bone marrow chromo ...1979473226
neurogenesis in the basal forebrain of the chinese hamster (cricetulus griseus). i. time of neuron origin.the time of neuron origin has been determined in the basal ganglia and related basal forebrain structures of the chinese hamster with the aid of 3h-thymidine autoradiography. large-celled structures like the globus pallidus, nucleus of the horizontal limb of the diagonal band of broca as well as large cells in the rostral part of the substantia innominata, in the caudate-putamen-complex and in the olfactory tubercle arise early (e12--e16), whereas medium-sized and small cells in the basal forebr ...1979475002
g1 phase chinese hamster v79-379a cells are inherently more sensitive to platinum bound to their dna than mid s phase or asynchronously treated cells. 1979475817
enhancement of the chromosome-damaging action of ascorbate by transition metals.freshly prepared ascorbate inhibited mitosis and induced chromosome aberrations in cultured chinese hamster ovary cells. cu(ii) and mn(ii) (10(-4) or 10(-5) m) enhanced both actions. fe(ii) and fe(iii) (10(-4) or 10(-5) m) reduced or abolished the mitosis-inhibiting action of ascorbate. at 10(-4) m, fe(ii) and fe(iii) strongly enhanced the chromosome-damaging capacity of ascorbate. up to 100% of all examined metaphase plates had multiple chromosome exchanges or breaks. since the cytostatic and c ...1979476651
mutagenicity testing on chinese hamster v79 cells treated in the in vitro liver perfusion system. comparative investigation of different in vitro metabolising systems with dimethylnitrosamine and benzo[a]pyrene.a comparative study of three in vitro metabolising systems was performed in combination with chinese hamster v79 cells, at which point mutation to 6-thioguanine resistance was scored. the three metabolising systems used were: (1) rat liver microsomal fraction (s9-mix); (2) feeder layer of primary embryonic golden hamster cells, according to hubermann's system; (3) in vitro perfusion of rat liver according to the system of beije et al. as model substances dimethylnitrosamine (dmn) and benzo[a]pyr ...1979476853
regional assignment of human genes tpi1, gapdh, ldhb, shmt, and pepb on chromosome 12.karyological analysis was performed on a series of human-chinese hamster cell hybrids containing deletions of human chromosome 12. chromosome breakage was produced by treatment of the cells with either x-rays or 5-bromodeoxyuridine and near-visible light. the hybrid clones were analyzed for the presence or absence of the following five human gene markers known to be located on chromosome 12: triosephosphate isomerase-1 (tpi1), glyceraldehyde-3-phosphate dehydrogenase (gapdh), lactate dehydrogen ...1979477403
pattern of segregation of chicken hprt phenotype in chinese hamster-chick red blood cell hybrids.the pattern of segregation of hypoxanthine phosphoribosyltransferase (hprt, e.c. was determined in synchronized chinese hamster-chick red blood cell hybrids. three hybrid lines were synchronized at the g1-s boundary. bromodeoxyuridine pulses were subsequently applied throughout the s phase, and the frequency of the segregant clones was determined. it was found that the segregation of the chicken-specific hprt phenotype associated with the loss of a chromosome was potentiated by bromodeo ...1979477410
sister chromatid exchanges in vivo in chinese hamster embryonic liver cells exposed transplacentally to brdu. 1979477415
inhibitory effect of guanyl nucleotides toward adenylate cyclase activity of chinese hamster ovary cell membranes activated in vitro by cholera toxin. 1979479151
a concanavalin a-resistant chinese hamster ovary cell line is deficient in the synthesis of [3h]glucosyl this report we present an initial determination of the biochemical defect present in a chinese hamster ovary cell line selected for resistance to concanavalin a. membranes of this mutant, b211, incorporated at least 10-fold less mannose from gdp-[14c]mannose into oligosaccharide-lipid than membranes of the wild type. in the presence of dolichol phosphate, membranes of the mutant and wild type exhibited similar rates of synthesis of number of early intermediates, namely, mannosylphosphoryldoli ...1979479186
insensitivity of a ricin-resistant mutant of chinese hamster ovary cells to fusion induced by newcastle disease virus.the role of membrane components in the interaction of cells with newcastle disease virus (ndv) was studied using a ricin-resistant mutant of chinese hamster ovary cells (cho-15b), in which there is a deficiency in distal saccharides at the plasma membrane. compared to the parental wild type, the mutant was shown to be 4- to 10-fold less sensitive to either fusion from without or fusion from within induced by ndv. the mutant and wild type were nearly indistinguishable with respect to other intera ...1979480463
vitamin c is positive in the dna synthesis inhibition and sister-chromatid exchange tests.ascorbate caused a dose-dependent increase in sister-chromatid exchanges (sces) in chinese hamster ovary (cho) cells and in human lymphocytes. moreover, in the dna synthesis inhibition test with hela cells, ascorbate gave results typical of dna-damaging chemicals. catalase reduced sce induction by ascorbate, prevented its cytotoxicity in cho cells, and prevented its effect on hela dna synthesis. ascorbate reduced induction of sce in cho cells by n-methyl-n'-nitro-n-nitrosoguanidine (mnng) by dir ...1979481430
mutagenicity of 8-methoxypsoralen and long-wave ultraviolet irradiation in v-79 chinese hamster cells. a first approach to a risk estimate in photochemotherapy.the effect of 8-methoxypsoralen (8-mop) and long-wave ultraviolet irradiation (uva) on cell killing and mutation induction was studied in v-79 chinese hamster cells. no effect was observed after treatment with 8-mop alone (50 microgram/ml, 4 h), uva alone (9000 j/m2), or 8-mop metabolized by rat-liver microsomes. combined treatment with 8-mop and uva induced both cell killing and mutation. this was also observed under conditions approaching patient treatment with puva photochemotherapy with resp ...1979481433
facilitation by pyrimidine deoxyribonucleosides and hypoxanthine of mutagenic and cytotoxic effects of monofunctional alkylating agents in chinese hamster cells.hypoxanthine (hx), thymidine (tdr) and deoxycytidine (cdr), at concentrations of 10(-5) m increased the yield of 8-azaguanine-resistant (azgr) mutants induced by n-methyl-n'-nitro-n-nitrosoguanidine (mnng) in cultured chinese hamster v79 cells. the cytotoxicity of mnng was increased 2-fold in the presence of hx, and more than 10-fold in the presence of tdr. this cytotoxic effect of tdr was abolished by equal concentrations of cdr, which by itself did not increase the cytotoxicity of mnng. howeve ...1979481439
induction of 8-azaguanine- and ouabain-resistant mutants by cyclophosphamide and 1-(pyridyl-3)-3,3-dimethyltriazene in chinese hamster cells cultured in diffusion chambers in mice.a host-mediated assay is described for induction of 8-azaguanine-resistant (azgr) and ouabain-resistant (ouar) mutants in chinese hamster v79 cells cultured in diffusion chambers (dc) in c3h mice. injection of the hosts with the indirect mutagen/carcinogen cyclophosphamide (cpp) or 1-(pyridyl-3)-3,3-dimethyltriazene (pydt) caused a dose-dependent increase in mutation frequency at the loci of azgr and ouar in the v79 target cells. plating efficiency of v79 cells in dc in mice was decreased depend ...1979481447
chromosomal aberrations and sister-chromatid exchanges in chinese hamster cells treated in vitro with hexavalent chromium compounds.chinese hamster cells (cho line) were treated in vitro for 30--39 h with hexavalent chromium compounds (k2cr2o7 and na2cro7), at concentrations ranging from 0.1 to 1.0 microgram of cr6+ per ml, in medium containing budr. chromosomal aberrations and sister-chromatid exchanges were scored on budr-labelled 2nd division metaphases, collected at the end of treatment and stained with giemsa. treatment with mitomycin c 0.009--0.030 microgram/ml) was carried out as a control for the responsiveness of th ...1979481449
chromosomal aberrations induced by maleic hydrazide and related compounds in chinese hamster cells in vitro.the cytotoxic effects and chromosomal abnormalities induced by maleic hydrazide (mh) and its salts were investigated in cultured v79 cells. mh, and its potassium (k-mh) and diethanolamine (dea-mh) salts were tested. mh was 5--14 times more cytotoxic than its salts and almost 4.5 times less toxic than the related compound, hydrazine dihydrochloride (hdc). mh salts had very weak cytotoxicity; the ld50 values on v79 cells on exposure for 3 h in vitro were (in microgram/ml) 1100 (mh), 12 000 (dea-mh ...1979481451
mutagenicity, cytotoxicity and dna crosslinking in v79 chinese hamster cells treated with cis- and trans-pt(ii) diamminedichloride.the mutagenicity and cytotoxicity of cis- and trans-pt(ii) diamminedichloride (pdd) were examined in v79 chinese hamster lung cells and compared with effects on dna measured by alkaline elution. dna--protein crosslinks and dna interstrand crosslinks were detected following doses of cis-pdd which reduced cell survival 80--90% and which produced a mutant frequency of 3 x 10(-4) at the hgprt locus. equitoxic doses of trans-pdd were much less mutagenic than cis-pdd. at equitoxic doses, trans-pdd pro ...1979481452
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