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assignment of the structural genes for the alpha subunit of hexosaminidase a, mannosephosphate isomerase, and pyruvate kinase to the region q22-qter of human chromosome 15.concordant segregation of the expression of the alpha subunit of human hexosaminidase a, human mannosephosphate isomerase, and pyruvate kinase was observed in somatic cell hybrids between either thymidine kinase-deficient mouse cells or thymidine kinase-deficient chinese hamster cells and human white blood cells carrying a translocation of the distal half (q 22-qter) of the long arm of chromosome 15 to chromosome 17. a positive correlation was established between the expression of these human ph ...1977341373
micrococcus luteus uv-endonuclease-sensitive sites and sister-chromatid exchanges in chinese hamster ovary cells. 1979390381
microsome-mediated mutagenesis in v79 chinese hamster cells by various nitrosamines.a microsome-mediated mutagenesis system has been established with the v79 chinese hamster cell line. the cells, grown in monolayer, were treated with various nitrosamines in the presence of a postmitochondrial fraction ((s15) from rat liver and a reduced nicotinamide adenine dinucleotide-generating system for 1 hr, washed and incubated for 2 to 3 hr in fresh culture medium, and then plated for toxicity and mutagenicity assays. mutation was determined by resistance to 20mug 8-azaguanine per ml. i ...1977321116
mutagenicity studies of 4-(2-carboxyethyl) phenyl trans-4-aminomethylcyclohexane carboxylate hydrochloride (dv-1006). a new antiulcer drug.an antiulcer drug, 4-(2-carboxyethyl) phenyl trans 4-aminomethylcyclohexane carboxylate hydrochloride (dv-1006), was studied for mutagenicity using bacterial systems, in vitro and in vivo cytogenetics, and dominant lethal tests. no mutagenicity of dv-1006 was observed either in the rec-assay on bacillus subtilis or in the salmonella/microsome test (ames test). in in vitro cytogenetics, dv-1006 had no effects on the chromosomes of chinese hamster cells at cytotoxic doses. rats were treated singly ...1979391178
assay method for vibrio cholerae and escherichia coli enterotoxins by automated counting of floating chinese hamster ovary cells in culture medium.as chinese hamster ovary (cho) cells on plastic proliferate, many cells float off into the medium instead of piling up after they form a monolayer. fewer cells were floating in the medium when cho cells were incubated with cholera toxin at a concentration as low as 10 pg/ml. the toxin increased the adhesiveness of the cells forming confluent monolayers so that the floating cells accumulated on the adherent monolayers. on the basis of this finding, a simple, quantitative assay method for cholera ...1978350897
[recent developments of instrument assisted chromosome analysis with quantimet 720 (author's transl)].the system looks in a short time automatically for good metaphase spreadings. two routines are described which evaluate the relocated metaphases in a semi-automatic way. one routine classifies human chromosomes, using the chromosome area and area ratio of the chromosome arms. the other routine classifies the chromosomes of the chinese hamster. in this routine statistical inputs for chromosome aberrations are possible.1979396456
in vitro mutagenicity and cell transformation screening of caprolactam.caprolactam was tested for genetic activity in bacterial and mammalian screens. it was inactive in the following tests: a) salmonella/microsome mutagenicity; b) chinese hamster ovary cell mutagenicity (induction of 6-thioguanine mutants); c) enhancement of sa7 virus transformation of primary hamster embryo cells, when administered before or after virus, and; d) chemical transformation of secondary hamster embryo cells.1979399920
mutagenicity and cytotoxicity of benz[alpha]anthracene diol epoxides and tetrahydro-epoxides: exceptional activity of the bay region 1,2-epoxides.three diastereomeric pairs of diol epoxides, two tetrahydro-epoxides, and the k-region oxide of the polycyclic aromatic hydrocarbon benz[a]anthracene were evaluated for mutagenic activity in strain ta 100 of salmonella typhimurium and in line v79-6 of chinese hamster lung cells. the two diastereomeric 1,2-epoxides of the trans-3,4-dihydrodiol of benz[a]anthracene are 15 to 35 times more mutagenic to the bacteria and 65 to 125 times more mutagenic to the mammalian cells than are the diastereomeri ...1977331315
characterization of alpha-galactosidase isoenzymes in normal and fabry human-chinese hamster somatic cell hybrids.the alpha-galactosidases in normal man-chinese hamster somatic cell hybrids were investigation with antibodies specific for human alpha-galactosidase a and antibodies specific for chinese hamster alpha-galactosidase. it was found that an isoenzyme in hybrid cells, which has an electrophoretic mobility between that of human alpha-galactosidase a and chinese hamster alpha-galactosidase, contains immunologic determinants of both human and chinese hamster origin, suggesting that it is a heteropolyme ...1977404232
assay of escherichia coli heat-labile enterotoxin with vero cells.the continuous cell line of african green monkey kidney, vero, showed characteristic morphological changes in response to culture filtrates from toxigenic strains of escherichia coli. the response compared favorably with that of y-1 (mouse adrenal) and cho (chinese hamster ovary) cells. vero cells were the simplest and most economical to maintain in the laboratory.1977405326
selection and characterization of cells resistant to diphtheria toxin and pseudomonas exotoxin a: presumptive translational mutants.two classes of diphtheria toxin-resistant variants were selected from chinese hamster ovary (cho-k1) cells: permeability variants, in which uptake of toxin was impaired, and a new class of cytoplasmic variants, which were cross-resistant to pseudomonas exotoxin. ef-2 prepared from the cytoplasmic variants was resistant to adp-ribosylation by either toxin. the evidence presented suggests that these are translational variants possessing a mutationally altered ef-2 gene product. these studies also ...1977408012
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
characterization of residual hexosaminidase activity in sandhoff's disease using man-chinese hamster cell hybrids.to 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
bromodeoxyuridine tablet methodology for in vivo studies of dna synthesis.5-bromodeoxyuridine (brdu) tablets with different physical characteristics are useful in a wide variety of studies requiring detection of dna replication in vivo. these tablets can effect a high substitution of brdu in dna, thereby permitting sister chromatid differentiation in chromosomes stained with 33258 hoechst alone or in conjunction with giemsa. baseline and cyclophosphamide-induced in vivo sister chromatid exchange frequencies in mouse spleen, marrow, and thymus were measured and found t ...1978356290
use of human-liver microsomes from kidney-transplant donors for the induction of chromatid aberrations and sister-chromatid exchanges by means of pre-carcinogens in chinese hamster cells in vitro.samples of two human livers taken during operation of kidney donor patients were processed for microsome fractions and used for metabolization of cyclophosphamide (cp) and dimethylnitrosamine (dmn) in combination with the nadph-generating system. rat-liver microsomes were checked for comparison. induction of chromatid aberrations and sister-chromatid exchanges in a newly isolated clone of chinese hamster fibroblasts served as indicators of activity. human s-9 fractions standardized on protein co ...1978362179
slit-scan flow cytometry of mammalian chromosomes.a flow cytometer has been constructed which measures total fluorescence and the distribution of fluorescence along isolated, stained mammalian chromosomes. in this device, chromosomes flow lengthwise at 4 m/sec through a 1-micrometer thick laser beam. the fluorescence from each chromosome is recorded at 10 nsec intervals; the sequence of recorded values represents the distribution of fluorescence along the chromosome and is stored in the memory of a waveform recorder. the total fluorescence of e ...1979374608
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
comparison of the induction by cigarette smoke condensates of sister-chromatid exchanges in chinese hamster cells and of mutations in salmonella typhimurium.three cigarette smoke condensates were tested for the induction of sister-chromatid exchanges in ovary cells of the chinese hamster and for mutations in salmonella typhimurium. in the sister-chromatid exchange test an effect was obtained that was not enhanced by the inclusion of a system for metabolic activation. in the salmonella test, an effect was only obtained by including rat-liver homogenates derived from rats treated with inducers of the enzyme systems necessary for metabolic activation. ...1979375084
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
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
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
mutagenesis of chinese hamster cells in vitro by combination treatments with methyl methanesulfonate and n-acetoxy-2-acetylaminofluorene.mutational synergism was examined in chinese hamster v79 cells exposed to methyl methanesulfonate followed by n-acetoxy-2-acetylaminofluorene (acaaf) at different time intervals. treatment with 500 micron methyl methanesulfonate resulted in 95% survival of cloning ability and induced approximately 4 azaguanine-resistant mutants/10(5) survivors. seven micron acaaf produced 10 times as many mutants, and the survival was 7%. lethal synergism was observed for methyl methanesulfonate treatments follo ...1978208770
chromosomal aberration tests on 29 chemicals combined with s9 mix in vitro.a metabolic activation system with rat-liver microsome fraction plus cofactors (s9 mix) was applied to chromosomal aberration tests in vitro for the screening of chemical mutagens or carcinogens in the environment. dialkylnitrosamines only induced chromosomal aberrations in chinese hamster cells (chl) when treated with s9 mix. the incidence of chromosomal aberrations in chl varied with experimental conditions, e.g. incubation time, recovery time, components of s9 mic and inducers used for prepar ...1979375085
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
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
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
carcinogenicity of 2-hydroxybenzo(a)pyrene and 6-hydroxybenzo(a)pyrene in newborn mice.benzo(a)pyrene (bp), 2-hydroxybenzo(a)pyrene (2-hobp), and 6-hydroxybenzo(a)pyrene (6-hobp) were tested for tumorigenicity by i.p. injection into newborn mice. the mice were treated sequentially with 200, 400, and 800 nmol of compound on the first, eighth and fifteenth day of life, and the animals were killed at 24 weeks of age. treatment with 2-hobp caused about 4-fold more pulmonary tumors than bp, while 6-hobp had little or no tumorigenic activity. newborn mice treated with 2-hobp, bp, and 6- ...1979376121
tubulin and calmodulin. effects of microtubule and microfilament inhibitors on localization in the mitotic apparatus.indirect immunofluorescence was used to determine the distribution of calmodulin in the mitotic apparatus of rat kangaroo ptk2 and chinese hamster ovary (cho) cells. the distribution of calmodulin in ptk2 cells was compared to the distribution of tubulin, also as revealed by indirect immunofluorescence. during mitosis, calmodulin was found to be a dynamic component of the mitotic apparatus. calmodulin first appeared in association with the forming mitotic apparatus during midprophase. in metapha ...1979379022
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
mutagenicity of 8-ethoxycaffeine in vitro. induction of point mutations in the salmonella/microsome test and of sister-chromatid exchanges as well as chromosomal aberrations in chinese hamster ovary cells (cho line).the caffeine derivative 8-ethoxycaffeine (eoc) was tested in 3 different test systems in vitro. each experiment was carried out with and without s9 mix. incubation temperatures were 20 and 37 degrees c. (1) in the salmonella/microsome test, eoc behaved as a pro-mutagen in the salmonella typhimurium strain ta1535. no mutagenic activity was found in experiments without s9 mix. the influence of temperature was negligible. the mutagenic activity of eoc depended mainly on the mammals used to prepare ...1979384216
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. 2.4.2.8) 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
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
mutagenic activity of rhodamine dyes and their impurities as detected by mutation induction in salmonella and dna damage in chinese hamster ovary cells.commercial rhodamine dyes 6g and b induce his+ reversion mutations in salmonella and single-strand breaks in chinese hamster ovary cells, as detected by alkaline sucrose sedimentation. aroclor 1254-induced rat liver homogenate (s9) is required for production of genetic activity by these dyes. rhodamine 6g induces both frameshift and base substitution mutations, whereas rhodamine b induces only frameshift mutations. rhodamine 6g is genetically more active and more toxic than is rhodamine b in bot ...1979387214
activity of citrinin metabolized by rat and human microsome fractions in clastogenicity and sce assays on chinese hamster v79-e cells.the mycotoxin citrinin is a potent inducer of chromosomal aberrations in the clastogenicity assay on v79-e cells when metabolized by rat and human liver microsomes. rat and human liver microsomes, standardized on protein content, activate citrinin at equal levels. 5 x 10(-4) m citrinin induces complex translocations in a high frequency as well as defects of chromosomal coiling. higher concentrations are cytotoxic, lower ones are almost inactive. after metabolization of mycotoxin by rat-kidney mi ...1979481457
the effect of aphidicolin on adenovirus dna synthesis.aphidicolin inhibits adenovirus dna replication in hela cells and in a cell-free, infected, nuclear extract in which viral dna is elongated. the compound inhibits alpha dna polymerase, extensively purified from hela cells, but has little or no effect on the beta or gamma dna polymerases similarly purified. aphidicolin does not affect thymidine uptake by cells nor does synthesis as it also inhibits dna replication in uninfected cells. the inhibition by aphidicolin is reversible if the drug is rem ...1979482131
differences in mutagenicity and cytotoxicity of (+)- and (-)-benzo[a]pyrene 4,5-oxide: a synergistic interaction of enantiomers.in order to study the biological effects of (+)- and (-)-benzo[a]pyrene 4,5-oxide, a synthesis of these molecules has been developed based on the resolution of (+/-)-cis-4,5-dihydroxy-4,5-dihydrobenzo[a]pyrene. the (-) enantiomer of benzo[a]pyrene 4,5-oxide was 1.5- to 5.5-fold more mutagenic than the (+) enantiomer in strains ta 98, ta 100, ta 1537, and ta 1538 of salmonella typhimurium and in chinese hamster v79 cells. in studies with v79 cells, the (-) enantiomer of benzo[a]pyrene 4,5-oxide w ...1979388437
effects of asbestos on epithelioid cell lines.the in vitro effects of asbestos fibers on the growth and viability of cho cells, an epithelioid cell line derived from chinese hamster ovary, and on k-22 cells, an epithelial cell line derived from rat liver, have been studied. relatively low concentrations of asbestos (10 micrograms/ml) were quite cytotoxic to both cell types. a sample of chrysotile asbestos was more toxic than samples of crocidolite or amosite. the toxic factor could not be extracted from the asbestos and toxicity occurred on ...1978233816
chromosome breaking activity of human feces and its enhancement by transition metals.chloroform-methanol extracts from human fecal samples were found to contain compounds which induce chromosome aberrations in chinese hamster ovary cells. the induction of chromosome aberrations is stimulated by cu2+ or mn2+ and inhibited by fe2+ or fe3+. addition of catalase to the fecal extract or the mixture of fecal extract and mn2+ reduced the frequency of chromosome aberrations. these properties are indicative of hydroxyradical producing agents.1979489168
in vitro mutagenicity and cell-transformation screening of n-(2,3-epoxy-propyl)-phthalimide.n-(2,3-epoxy-propyl)-phthalimide (epp) was tested for genetic activity in the salmonella/microsome mutagenicity test. concentration-dependent mutagenicity was demonstrated in s. typhimurium strains ta1535, ta1537 and ta100 with and without rat s9. it was inactive in strain ta1538, and active without rat s9 in ta98 at the high dose. epp induced 6-thioguanine-resistant mutants of chinese hamster ovary cells in the absence of an exogenous activating system. epp produced dose-dependent enhancement o ...1979390395
stable association of the human transgenome and host murine chromosomes demonstrated with trispecific microcell hybrids.trispecific microcell hybrids were prepared by transferring limited numbers of chromosomes from a human/mouse gene-transfer cell line to a chinese hamster recipient line. the donor cells employed were murine l-cells that stably expressed the human form of the enzyme hypoxanthine phosphoribosyltransferase. karyotypic, zymographic, and back-selection tests of the resulting human/mouse/chinese hamster microcell hybrids provided strong genetic evidence for a stable association of the human transgeno ...1977269444
sperm-cell multinucleates in chinese hamster ovary cells penetrated with rat spermatozoa. 1979498198
two-dimensional analysis of proteins associated with heterogenous nuclear rna in various animal cell lines.the protein complement of heterogenous nuclear rna . protein particles from human hela, mouse l and chinese hamster (cho) cells has been analysed by two-dimensional gel electrophoresis using the two techniques described by o'farrell [j. biol. chem. (1975) 250, 4007--4021 and cell (1977) 12, 1133--1142]. over a hundred individual spots habe been reproducibly detected both l-[35s]methionine. large similarities, especially in the 25 000--40 000 mr cluster of basic protein, were found among these th ...1979499201
activity of both mouse and chinese hamster ribosomal rna genes in somatic cell hybrids. 1979499371
persistence of the fc cytophilic antibody receptor in macrophage hybrid cells.hybrid cell clones were obtained from mouse macrophase/ehrlich ascites cell fusions which showed the 'fc' cytophilic antibody receptor site, phagocytosis and motility typical of macrophages. with continued growth of the clones for 11 weeks, the receptor became undetectable but could be unmasked by dilute trypsin treatment; subsequent remasking of the receptor could be prevented with cycloheximide treatment of the hybrid cells. these hybrids produced cystic anaplastic tumours in neonatal irradiat ...1978400978
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
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
culture of adult rat lung cells: benzo(a)pyrene metabolism and mutagenesis.a method is described for obtaining and culturing large numbers of lung cells from normal adult male rats. the lungs were perfused in situ to remove blood cells and then perfused via the trachea with a trypsin-collagenase solution to initiate tissue digestion. the tissue was further digested in the enzyme solution and approximately 2 x 10(8) viable lung cells were obtained per animal. primary cultures contained a mixed cell population. through eight subcultures about 70% of the cell population p ...1979511205
amosite, chrysotile and crocidolite asbestos are mutagenic in chinese hamster lung cells.chinese hamster lung cells cultured in the presence of amosite, chrysotile or crocidolite displayed inhibition of cell growth. phagocytosis of asbestos by cells was observed. amosite and chrysotile appeared to be twice as toxic as crocidolite based on an equal weight/volume basis. induction of 6-thioguanine resistance was studied. after treatment at 10 microgram/cm2 for 24 h, and with a 48-h expression time, numerically the cells did not change significantly from 6-thioguanine-sensitive to 6-thi ...1979514306
inducers of dna synthesis present during mitosis of mammalian cells lacking g1 and g2 phases.the cell cycle analysis of chinese hamster lung fibroblast v79-8 line by the premature chromosome condensation method has confirmed the absence of measurable g1 and g2 periods. sendai virus-mediated fusion of mitotic v79-8 cells with g1 phase hela cells resulted in the induction of both dna synthesis and premature chromosome condensation in the latter, indicating the presence of the inducers of dna synthesis above the critical level not only throughout s phase, as it is in hela, but also during ...1978283413
the mechanism of action of cis-dichloro-bis (isopropylamine) trans dihydroxyplatinum iv (chip) on chinese hamster and c3h mouse tumor cells and its interaction with x-irradiation. 1979528286
adaptation of the influenza virus a2-pol 29/69 to the cells of the chinese hamster lung (chl) and to the cells bhk-21.in the course of research of the possibilities of adapting the influenza virus serotype a 2-pol 29/69 to bhk-21 and chl cells its production was established in the investigated combinations. an indication of virus replication is an increase in infectious and haemagglutination titres within 48 h after infection and gradual increase in haemadsorption. observation of the influence of trypsin (10 microgram/ml) indicates that trypsin increases the capability of viruses to penetrate the cells. the cyt ...1979535814
selecting interspecific human-mouse and chinese hamster-mouse hybrids using a new half-selection technique with a polyene antibiotic.interspecific human-mouse and chinese hamster-mouse hybrids were isolated from polyethylene glycol fused cells by a new half-selection technique employing a structurally modified polyene macrolide antibiotic, amphotericin b methyl ester (ame), and hat media. unfused parental cells were killed as a result of innate sensitivity to ame or their genetic deficiency, absence of thymidine kinase (tk-) or hypoxanthine guanine-phosphoribosyl transferase (hgprt-). in contrast, hybrid colonies were isolate ...1979541268
isolation and characterization of tunicamycin resistant mutants from chinese hamster ovary cells.stable clones selected for resistance to tunicamycin (tm) have been isolated from chinese hamster ovary (cho) cells. the tmr phenotype is stable for more than nine months in the absence of the drug. the morphology of tmr mutant varies from epitheloid to abnormally elongate. the mutants do not display cross-resistance for cona but are slightly cross-resistant to pha. biochemically labeled membrane proteins and glycoprotein of vesicular stomatitis virus (vsv) grown in the tmr mutants revealed that ...1979541348
genetic transmission of moloney leukemia virus: mapping of the chromosomal integration site.mice genetically transmitting the exogenous moloney leukemia virus (balb/mo) have been previously derived. these animals carried one copy of moloney virus dna (m-mulv) in their germ line and transmitted the virus as a single mendelian gene to the next generation. homozygous balb/mo mice were used to genetically map the m-mulv locus. embryo fibroblasts were fused to established chinese hamster cells and somatic cell hybrids were selected. segregation of mouse chromosomal markers in the hybrids wa ...1979544367
destruction of bacterial viruses in serum by heat and radiation under conditions that sustain the ability of serum to support growth of cells in suspended culture.methods for inactivating bacterial viruses in serum were developed through the use of heat and ionizing radiation, and the effects of these treatments on the growth rates of cultured cells were tested. viruses chosen for this study were the radiation-resistant bacteriphage f2 and heat-resistant phage t4. the viabilities of these phages were reduced more than 2 and 4 orders of magnitude, respectively, by a treatment at 60 degrees c for 30 min followed by 420 krads of ionizing radiation. simultane ...1979544633
assignment of the gene for cytoplasmic superoxide dismutase (sod-1) to a region of chromosome 16 and of hprt to a region of the x chromosome in the mouse.in the search for homologous chromosome regions in man and mouse, the locus for cytoplasmic superoxide dismutase (sod-1; superoxide:superoxide oxidoreductase, ec 1.15.1.1) is of particular interest. in man, the sod-1 gene occupies the same subregion of chromosome 21 that causes down syndrome when present in triplicate. although not obviously implicated in the pathogenesis, sod-1 is considered to be a biochemical marker for this aneuploid condition. using a set of 29 mouse-chinese hamster somatic ...1979291939
direct linkage of thrombin to its cell surface receptors in different cell types.when 125i-thrombin was incubated with foreskin fibroblasts, cervical carcinoma cells or fibrosarcoma cells of human origin, or with secondary chick embryo cells or chinese hamster lung cells, it became directly linked to its cell surface receptors. the thrombin-receptor complex (th-r) was derived exclusively from a pool of 125i-thrombin that had become specifically bound to the cell surface. the linkage was probably covalent, since the complex was resistant to boiling in sodium dodecyl sulfate a ...1979544938
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
methods to evaluate the effects of toxic materials deposited in the lung on immunity in lung-associated lymph nodes.intratracheal instillation of sheep red blood cells (srbc) induced a primary immune response in lung-associated lymph nodes of chinese hamsters and fischer-344 rats. few or no anti-srbc antibody forming cells (afc) were found in the spleen or cervical lymph nodes after intratracheal immunization. the number of afc was significantly suppressed in the lung-associated lymph nodes from hamsters exposed by inhalation of 239puo2 and in rats exposed by intratracheal instillation of benzo(a)pyrene (bap) ...1979548254
influenza virus infection of a cell-cycle mutant of chinese hamster ovary cells. 1977558282
the effect of bromodeoxyuridine on the segregation of the chicken-specific hprt gene from chinese hamster-chick red blood cell somatic hybrids.the segregation of the chick-specific hprt gene was studied in three chinese hamster-chick red blood cell hybrid lines. the three lines showed individual segregation kinetics, the segregation taking place in an exponential-like fashion. bromodeoxyuridine becomes incorporated into the nuclear dna and increases the spontaneous segregation rate.1978299650
dna repair in v-79 cells treated with combinations of ultraviolet radiation and n-acetoxy-2-acetylaminofluorene.earlier experiments on human cells showed that n-acetoxy-2-acetylaminofluorene mimics ultraviolet radiation in biological and repair characteristics and that the amount of repair from a combined treatment was additive. chinese hamster v-79 cells are less proficient than human cells in excision repair of pyrimidine dimers resulting from irradiation. we therefore investigated the combined effects of both agents on repair in v-79 cells to see whether they follow the same pattern as in human cells. ...1977560253
replication of minute virus of mice in chinese hamster ovary fibroblasts.minute virus of mice (mvm), a parvovirus, replicates in chinese hamster ovary (cho) cells. although replication of the virus cannot readily be detected by haemagglutination, it can be measured by plaque assay on mouse strain lm cells.1977560425
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
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
critical importance of microsome concentration in mutagenesis assay with v79 chinese hamster cells.for optimum mutagensis in v79 chinese hamster cells, the amount of liver postmitochondrial fraction in the assay was found to be of critical importance, depending on the chemicals being tested. benzo[a]pyrene (bp) required lower (1-5%) concentrations of the liver 15 000 x g supernatant (s15) from methylcholanthrene pretreated rats for a maximum induction of cytotoxicity and mutagenicity, as determined by 8-azaguanine- and ouabain-resistance. a sharp peak of mutagenicity and cytotoxicity was indu ...1979392309
production of monoclonal antibodies against a cell surface concanavalin a binding glycoprotein.concanavalin a-binding (con-a)-binding cell surface glycoproteins were isolated, via con a-affinity chromatography, from triton x-100-solubilized chinese hamster ovary (cho) cell plasma membranes. the con a binding glycoproteins isolated in this manner displayed a significantly different profile on sodium dodecyl sulfate--polyacrylamide gels than did the triton-soluble surface components, which were not retarded by the con-a-sepharose column. [125i]-con a overlays of the pooled column fractions ...1979544930
assignment of the genes for triose phosphate isomerase to chromosome 6 and tripeptidase-1 to chromosome 10 in mus musculus by somatic cell hybridization.evidence is presented for the assignment of the gene for triose phosphate isomerase to mus musculus chromosome 6 and tripeptidase-1 to chromosome 10 by synteny testing and chromosome assignment in chinese hamster x mouse somatic cell hybrid clones. neither tpi nor trip-1 were expressed concordantly with any known isozyme markers in 45 hybrid clones (13 primary and 32 secondary). karyotypic analysis of 21 clones showed that the expression of tpi and chromosome 6 were concordant in all cases as wa ...1978566475
assignment of a mus musculus gene for triosephosphate isomerase to chromosome 6 and for glyoxalase-i to chromosome 17 using somatic cell hybrids.chinese hamster x mouse hybrid cells segregating mouse chromosomes have been used to assign a gene for triosephosphate isomerase (tpi-1, ec 5.3.1.1, mckusick no. 19045) to mouse chromosome 6, and a gene for glyoxalase-i (glo-1, ec 4.4.1.5, mckusick no 13875) to mouse chromosome 17. the genes for tpi-1 and lactate dehydrogenase b are syntenic in man and probably so in the dog. it is therefore likely that they are syntenic also in the mouse. it is of interest then that there is a mouse gene, ldr-1 ...1978566476
dna-mediated transfer of the adenine phosphoribosyltransferase locus into mammalian cells.in this report, we demonstrate the feasibility of transforming mouse cells deficient in adenine phosphoribosyltransferase (aprt; amp:pyrophosphate phosphoribosyltransferase, ec 2.4.2.7) to the aprt+ phenotype by means of dna-mediated gene transfer. transformation was effected by using unfractionated high molecular weight genomic dna from chinese hamster, human, and mouse cells and restriction endonuclease-digested dna from rabbit liver. the transformation frequency observed was between 1 and 10 ...1979286319
the action of af 2 on cultured hamster and human cells under aerobic and hypoxic conditions.af 2 (2-(2-furyl)-3-(5-nitro-furyl)acrylamide) was toxic to chinese hamster v 79 cells and normal human fibroblasts in aerobic media. however, the toxicity of the drug was increased many times by hypoxia. similarly, the frequency of af 2-induced azaguanine- and ouabain-resistant mutants of v 79 cells was much higher in hypoxia than under aerobic conditions. both hamster v 79 cells and human fibroblasts metabolized af 2 and other nitrofurans rapidly only under hypoxic conditions. human fibroblast ...1978566638
isolation of lysosomal alpha-mannosidase mutants of chinese hamster ovary cells.a method is presented for detection of lysosomal hydrolase activity in situ in colonies of chinese hamster ovary cells. this method was used to screen for mutants deficient in lysosomal alpha-mannosidase. mutagenized cells were replicated onto filter papers [esko, j. d. & raetz, c. r. h. (1978) proc. natl. acad. sci. usa 75, 1190-1193] and allowed to divide for 11-14 days; cells on the filter replicas were lysed, and the filters were incubated with 4-methylumbelliferyl-alpha-d-mannopyranoside at ...1979287030
somatic cell genetic analysis of transgenome integration.the site of association of the human transgenome and host murine chromosomes was determined in several subclones of a stable human/mouse transformed cell line. chromosomes were transferred from each of three transformed subclones into chinese hamster recipient cells, and selection was applied for the expression of human transgenome-encoded hprt. a series of trispecific microcell hybrids was isolated and characterized for each subclone. evidence is presented that, within a given transformed subc ...1979545718
assignment of the gene for glyoxylase i to mouse chromosome 17 by somatic cell genetics.evidence is presented for the assignment of the gene for glyoxylase i to mouse chromosome 17 using mouse x chinese hamster somatic cell hybrids. glo i was not expressed concordantly with any known marker enzymes which represented 11 linkage groups. the presence of chromosome 17 and expression of glo i were concordant in 31/31 clones. glo i is thus linked to the h-2 histocompatibility locus in the mouse.1978569476
amplified dihydrofolate reductase genes in unstably methotrexate-resistant cells are associated with double minute chromosomes.selection of mammalian cells in progressively increasing concentrations of methotrexate results in selective amplification of dna sequences coding for dihydrofolate reductase (tetrahydrofolate dehydrogenase, 5,6,7,8-tetrahydrofolate:nadp+ oxidoreductase, ec 1.5.1.3). in some cell variants the amplified genes are stable with growth in the absence of methotrexate, whereas in other variants the amplified genes are lost from the population. we have previously reported that in a stably amplified vari ...1979293670
genetic and biochemical analysis of the a1 cell-surface antigen associated with human chromosome 11.a highly versatile system for genetic, biochemical, and immunological analysis of human cell surface components has been developed using a human-chinese hamster somatic cell hybrid containing chromosome 11 as its only human chromosome. this system lends itself to studies such as identification of human cell surface antigens and other genetic markers, regional gene mapping of these markers on chromosome 11, mutational analysis of these markers, and exploration of distribution of these antigens in ...1979293736
cytogenetic characterization of chinese hamster-sheep somatic cell hybrids.the methods used to characterize cytogenetically chinese hamster x sheep somatic cell hybrids have been reported. g and c banding patterns on hybrid metaphases allowed the discrimination between hamster and sheep chromosomes, and in addition to establish the unidirectional loss of sheep chromosomes in hybrid cells.1979575764
segregation of human hypoxanthine phosphoribosyltransferase activity from somatic cell hybrids isolated from fusion of mouse gene transfer cells with chinese hamster cells. 1977561300
effects of wheat germ agglutinin on membrane transport.(1) low concentrations of wheat germ agglutinin are cytotoxic toward several tissue culture lines, including chinese hamster ovary cells, swiss 3t3 cells, mouse l cells and baby hamster kidney cells. the ld50 ranged from 1 to 5 microgram wheat germ agglutinin per ml. similar concentrations of the lectin inhibited the transport of the non-utilizable amino acids alpha-aminoisobutyric acid and cycloleucine and inhibited the uptake of thymidine. in contrast, 2-deoxy-d-glucose uptake was not altered ...1977561616
cycloheximide-resistance in chinese hamster ovary cells and human fibroblast cells. cytogenetic and biochemical characterization.cycloheximide(chm)-resistant mutant chinese hamster ovary (cho) and human cells were induced with n-nitrosomethylurea (nmu) and ethyl methanesulfonate (ems); the mutants were viable and showed unlimited growth in the presence of chm (7 x 10(-7) m), whereas this concentration inhibits protein synthesis in vivo as well as in vitro. no numerical or structural chromosomal aberrations were found in the mutant cells. in vitro analysis shows that the ribosomes confer resistance against cycloheximide.1979489015
mutagenesis by n-acetoxy-2-acetyl aminofluorene of chinese hamster v79 cells is unaffected by caffeine.8-azaguanine (azg)- and 6-thioguanine (tg)-resistant cells (mutants) were induced in chinese hamster v79-4 cells by 0.1--2.5 microgram/ml n-acetoxy-2-acetyle aminofluorine (acaaf) treatments in the presence of 5% fetal bovine serum (fbs). the frequency of resistant colonies increased from 1 to 47 per 10(5) survivors. the effect of caffeine (50--200 microgram/ml) during the mutagenesis expression period was determined by adding caffeine 1--24 h after acaaf. the medium was replaced after 48 h expo ...1978566636
time and cell systems as variables in fusion experiments with polyethylene glycol.cell hybridization was done between a monolayer of b14-150 chinese hamster cells and a suspension of either mouse leukemia cells or normal human lymphocytes. cell contact was obtained by centrifugation of the suspension cells onto the monolayer cells in a culture plate. cell fusion was done by means of polyethylene glycol (peg). the optimum time for peg exposure as well as the yield of hybrid cells differed markedly with the different combinations.1978566713
properties of the thymidine transport system of chinese hamster ovary cells as probed by nitrobenzylthioinosine.the transport of thymidine into chinese hamster ovary cells grown in suspension culture was measured under conditions in which thymidine was not metabolized, namely, when cells had been depleted of atp. the system transporting thymidine was saturable (kztm = 70 micron), rapid 50% of transmembrane equilibrium level attained within 8 sec), and was apparently shared by other nucleosides, but not thymine or hypoxanthine. 6([4-nitrobenzyl]thio)-9-beta-d-ribofuranosylpurine, "nitrobenzylthioinosine", ...1978568178
replicon sizes in mammalian cells as estimated by an x-ray plus bromodeoxyuridine photolysis method.a new method is described for estimating replicon sizes in mammalian cells. cultures were pulse labeled with [3h]thymidine ([3h]tdr) and bromodeoxyuridine (brdurd) for up to 1 h. the lengths of the resulting labeled regions of dna, lobs, were estimated by a technique wherein the change in molecular weight of nascent dna strands, induced by 313 nm light, is measured by velocity sedimentation in alkaline sucrose gradients. if cells are exposed to 1,000 rads of x-rays immediately before pulse label ...1978570067
turnover of tubulin and the n site gtp in chinese hamster ovary cells.radioactively labeled tubulin from chinese hamster ovary (cho) cells can be isolated by co-polymerization with nonradioactive porcine brain microtubule protein. 75% of the soluble tubulin in cho extracts co-polymerizes with the porcine protein through several cycles, without preferential loss of either cho or porcine subunits. after phosphocellulose chromatography of the co-polymerized microtubules, the cho tubulin is radiochemically homogeneous, as judged by sds-polyacrylamide gel electrophores ...1977562716
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
misonidazole and mtdq in combination: cytotoxic and radiosensitizing properties in hypoxic mammalian cells.a combination of misonidazole and mtdq (6,6'-methylene-bis-2,2,4 trimethyl-1,2-dihydroquinoline) has been tested for its radiation-sensitizing properties and cytotoxicity, using chinese hamster v79 cells cultured in vitro. both compounds sensitize hypoxic cells to the effects of x-rays, and when used in combination their sensitizing properties are additive. by contrast, the presence of mtdq completely inhibits the cytotoxicity that misonidazole exhibits towards hypoxic cells. these experiments s ...1979486306
sister chromatid exchanges and growth inhibition induced by the flame retardant tris(2,3-dipromopropyl) phosphate in chinese hamster cells.the effects of the flame retardant tris(2,3-dibromopropyl) phosphate (tris-bp) on growth, sister chromatid exchanges (sce), and chromosome aberrations of chinese hamster v79 cells cultured either in vitro or in diffusion chambers (dc) implanted into mice were studied. tris-bp caused a dose- and time-dependent reduction of cell growth as measured by colony-forming activities. a significant dose-dependent increase in sce was observed in v79 cells either in the cultures treated with tris-bp or in d ...1978642035
detection of small amounts of human dna in human-rodent hybrids.a method of measuring semi-quantitatively small amounts of human dna in irradiated human x mouse and irradiated human x chinese-hamster somatic cell hybrids is described. one method uses molecular hybridization of cell dna bound to nitrocellulose filters with a crna probe to cot 0--1 human dna. alternatively hybrid cell dna is reassociated in solution with a cot 0--1 fraction of nick-translated human dna. formamide buffers give specificity to the reaction. the detection limit of the filter metho ...1979521473
measurement of mutagenesis in mammalian cells.a method using mammalian cells in vitro for detection and quantitation of mutagenic actions that appears to be useful for screening for carcinogenesis and genetic damage by environmental agents is presented. the method involves use of stable human--chinese hamster ovary hybrid cells that have retained a single human chromosome not necessary for cell reproduction. forward mutations are detected in genes necessary for production of specific human cell surface antigens. such mutants form colonies i ...1979286318
sister chromatid exchanges induced in cultured mammalian cells by chromate.chromate compounds induced sister chromatoid exchanges (sces) and chromosome aberrations in cultured mammalian cells. similar increases in sce frequency were observed in human fibroblasts exposed to the compounds k2cr2o7 and k2cro4. marked increases in sce frequency in cells exposed to chromate for a 48-h period were detected at concentrations between 10(-7) and 10(-6) m. chromosome aberrations (primarily chromatid breaks) were also produced in human cells exposed to k2cro4 at concentrations bet ...1979509691
a fluence response study of lethality and mutagenicity of white, black, and blue fluorescent light, sunlamp, and sunlight irradiation in chinese hamster ovary cells.under a set of defined experimental conditions, the fluence response of chinese hamster ovary (cho) cells to various light sources was studied by measuring single-cell survival and mutation to 6-thioguanine (tg) resistance. fluorescent white, black, and blue lights were sightly lethal and mutagenic. sunlamp light was highly lethal and mutagenic, exhibiting these biological effects within 15 sec of exposure under conditions recommended by the manufacturer for human use. lethal and mutagenic effec ...1977593289
inhibition of post-replication repair by isonicotinic acid hydrazide.in the presence of the alkylating mutagen n-methyl-n-nitrosourea (mnu), the well-known tuberculostatic ionicotinic acid hydrazide (inh), even in otherwise ineffective doses, depressed cell number and mitotic index in peripheral human lymphocytes and inhibited the post-replication repair process in chinese hamster cells (cho). inh had no influence on unscheduled dna synthesis (cut-and-patch repair), which was negligible in cho cells under our conditions.1978651939
correlation between characteristics of transformation and malignancy of intra and interspecific somatic hybrid cells.the transformed properties of five hybrid cell lines which had either one or another parent in common were studied and compared with their tumorigenicity. three hybrid cell lines, derived from the chinese hamster dc-3f/adx/aza line, were resistant to actinomycin-d. this property seemed to be correlated with the presence of a marker chromosome from the common parent. the tumorigenicity was intermediate between those of the parent cell lines. on the other hand, agglutinability by concanavalin a (c ...1978652265
human beta-glucuronidase: assignment of the structural gene to chromosome 7 using somatic cell hybrids.beta-glucuronidase (gus) has become an important enzyme model for the genetic study of molecular disease, enzyme realization, and therapy, and for the biogenesis and function of the lysosome and lysosomal enzymes. the genetics of human beta-glucuronidase was investigated utilizing 188 primary man-mouse and man-chinese hamster somatic cell hybrids segregating human chromosomes. cell hybrids were derived from 16 different fusion experiments involving cells from ten different and unrelated individu ...1977559490
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