TitleAbstractYear(sorted ascending)
regional mapping of the human no. 1 and x chromosome in interspecific cell hybrids using an x/1 translocation.fibroblasts from a carrier of an x/1 translocation, 46,xy,t(x;1)(q28;q31), were fused with chinese hamster cells. the resulting hybrids were analyzed for human no. 1 and x-chromosome markers. the data indicate that the loci for pgm1, pgd, pph, and guk1 are situated either in the long arm proximal to a break point in band 1q31 or in the short arm. the loci for pep-c, fh, and guk1 are located distal to the break point. hprt and g6pd are probably situated distal to a break point in band q28 of the ...19751238234
a comparison of the 8-azaguanine and ouabain-resistance systems for the selection of induced mutant chinese hamster cells.the forward mutation selection system based on resistance to 8-azaguanine has been widely used with cells cultured from a diversity of species and with a variety of mutagens. ouabain resistance is an alternative selective system. both systems show a substantial influence of expression time on the number of resistant variants observed after addition of the selective agent such that the frequency reaches a maximum which is dose dependent, and then declines rapidly. metabolic cooperation has been p ...19751240591
[dependence of immune cytolysis of cells infected with western equine encephalomyelitis virus upon the cell cycle stages].in the first few hours after inoculation of chinese hamster cells with western equine encephalomyelitis virus the mitotic activity of the cells did not change significantly but mitoses stopped mainly in the stage of metaphase and had all signs of pathological mitoses. treatment of the cells for 1 hour with the homologous antiviral immune serum and complement resulted in destruction and death of practically all cells except those in the state of mitosis. in the latter specific fluorescence of vir ...19751241178
[characteristics of somatic cell hybrids (mouse x chinese hamster) with a different ratio of chromosome sets from the parent species. ii. thymidine kinase activity].the activity of thymidine kinase (tk) was studied in series of somatic cell hybrids between the mouse cell line 3t3-4e (tk-) and chinese hamster cells m-15-1 (hgprt-). four groups of hybrid lines with different ratio of parental chromosome sets have been investigated: 1) three lines containing one hamster and one mouse chromosome set (1 hs+1 ms); 2) one line with 2 hs+1 ms; 3) one line containing 3 hs+1 ms and 4) one line containing 1 hs+2 ms. mixtures of extracts from the parental cells were sh ...19751241540
[characteristics of somatic cell hybrids (mouse x chinese hamster) with ratios of chromosome sets different from the parent species. iv. an electrophoretic analysis of several enzymes of the dehydrogenase class].electrophoretic mobilities in polyacrylamide gel of five dehydrogenases: nadp-dependent malate dehydrogenase (nadp-mdh), 6-phosphogluconate dehydrogenase (6pgd), alcohol dehydrogenase (adh), glucose-6-phosphate dehydrogenase (g6pd) and glutamate dehydrogenase (gdh) were investigated in a series of mouse x chinese hamster somatic cell hybrids. seven hybrid lines with different ratio of chromosome sets of hamster and mouse: 1 : 1, 2 : 1, 3 : 1 and 1 : 2 respectively were studied. nadp-mdh and 6pgd ...19751241545
acrylonitrile biotransformation in rats, mice, and chinese hamsters as influenced by the route of administration and by phenobarbital, skf 525-a, cysteine, dimercaprol, or thiosulfate.female wistar rats, conventional albino mice, and chinese hamsters were given a single dose of acrylonitrile, 0.5 or 0.75 mm/kg body weight. the elimination in the urine of thiocyanate, which is the main metabolite of acrylonitrile, indicated a decreasing proportion of biotransformation after oral (over 20%), intraperitoneal, or subcutaneous (2 to 5%), and intravenous (1%) administration in rats. oral administration of acrylonitrile in hamsters and mice was also followed by higher biotransformat ...19751242300
absence of ultrafast processes of repair of single-strand breaks in mammalian, smith and kaplan (1972) reported that the yield of dna single-strand breaks (ssb) in e. coli is largely independent of the presence of molecular oxygen during irradiation. they suggested that the oxygen enhancement ratio (o.e.r.) normally observed is due to the presence of an ultrafast repair mechanism acting (in bacterial cells) mainly on anoxically-produced breaks. to determine whether similar mechanisms exist in mammalian cells, we carried out comparable experiments on two cell-lines, o ...1975804459
identification of hamster thymus-derived lymphocytes employing rabbit anti-hamster brain serum.rabbit anti-hamster brain sera prepared from the brains of syrian and chinese hamsters were evaluated for their potential to identify thymus-derived lymphocytes present in these animals. the unabsorbed antisera were cytotoxic in vitro for both homologous and heterologous thymocytes and splenocytes. following absorption with hamster liver and erythrocytes, the antisera remained toxic for thymocytes, but were less toxic for splenocytes. comparative testing of both the rabbit anti-syrian and anti-c ...1975807688
distribution of 2,2(1),4,4(1),5,5(1)-hexachlorobiphenyl in mice and chinese hamsters: dose dependent accumulation in the mouse bronchial mucosa.the distribution of 2,2(1),4,4(1),5,5(1)-hexachlorobiphenyl-14c was studied in mice and chinese hamsters using whole body autoradiography and liquid scintillation counting. the mice exhibited a strong and persistent accumulation of radioactivity in the bronchial mucosa, and this accumulation was not fully developed until about 24 hours after an intravenous injection. the labelled substance passed to the fetuses of pregnant mice and was also concentrated in the fetal bronchi. mice pretreated with ...1975812457
alpha-galactosidase in man-chinese hamster somatic cell hybrids. 1975812566
hemoglobin synthesis in somatic cell hybrids: coexpression of mouse with human or chinese hamster globin genes in interspecific somatic cell hybrids of mouse erythroleukemia cells.somatic cell hybrids were derived by fusion of mouse erythroleukemia cells with fractionated human marrow enriched in erythroblasts, or with chinese hamster fetal liver erythroid cells. such interspecific hybrid cells, when isolated in suspension culture, had retained nearly all the mouse chromosomes and had lost most of the human or chinese hamster chromosomes. however, two such hybrids (one human, the other hamster) studied 4-6 weeks after fusion, were found to contain several non-mouse chromo ...19751058482
inhibition of tubulin assembly by rna and other polyanions: evidence for a required protein.nonneural cell extracts contain a heat-stable, nondialyzable activity that will inhibit the spontaneous assembly in vitro of partially purified brain tubulin. the sensitivity of this inhibitory activity to ribonucleases but not to a variety of other hydrolytic enzymes indicates that the inhibitor is an rna. this conclusion is supported by the observation that purified rnas from sea urchins, chinese hamster ovary cells, and brain all inhibit spontaneous microtubule assembly in vitro. the syntheti ...19751059144
nucleus anomaly test and chromosomal analysis of bone marrow cells of the chinese hamster and dominant lethal test in male mice after treatment with fluorescent whitening agents.four fluorescent whitening agents (fwas) were tested for mutagenic activity after oral administration in the following three different mammalian test systems: (1) dominant lethal test in the male mouse; (2) cytogenetic studies on metaphase chromosomes from the bone marrow of the chinese hamster; (3) nucleus anomaly test in somatic interphase cells (bone marrow) of the chinese hamster. these investigations yielded no evidence of dominant lethal effects of any of the four compounds on the progeny ...19751064545
selenium is an essential trace nutrient for growth of wi-38 diploid human fibroblasts.the trace element selenium is essential for clonal growth of diploid fibroblasts from human fetal lung (wi-38) in media containing small amounts of serum protein. maximum growth stimulation is obtained when 30 nm neutralized selenious acid is added to a synthetic medium containing 1.5 mg/ml of dialyzed fetal bovine serum protein (equivalent to a 3% serum concentration). serum appears to be a source of selenium in most culture media, since higher concentrations of serum protein or whole serum mas ...19761064872
study of markers of human erythroid differentiation in hybrid cells.somatic cell hybrids exhibiting co-expression of the globin genes of two species were generated by fusion of mouse erythroleukemia cells with chinese hamster or human marrow erythroid cells. in contrast, extinction of the mouse globin genes occurred in hybrids formed between the erythroleukemia cells and human fibroblasts. direct detection of the human globin genes in human x mouse fibroblast hybrids was achieved by annealing of dna from these cells to human globin complementary dna. this method ...19761071439
genetics of somatic mammalian cells: genetic, immunologic, and biochemical analysis with chinese hamster cell hybrids containing selected human chromosomes.through hybridization of specific chinese hamster cell auxotrophs with human cells and selection in media lacking the nutritional supplements required by the former cells, a series of stable hybrid clones can be prepared. these hybrids have genomes consisting of a common part--the complete or almost complete set of chinese hamster chromosomes, plus a variable part--one or a few human chromosomes. the identity of the human chromosomes can be varied by utilizing different chinese hamster auxotroph ...19761061117
identification of mutagenic metabolites of benzo(a)pyrene in mammalian cells.the mutagenicity of benzo[a]pyrene and 15 of its derivatives, which included phenols, the benzo[a]yrene-4,5-epoxide (the k-region epoxide), dihydrodiols, two isomeric 7,8-diol-9,10-epoxides, a 6-methyl derivative, and a 6-hydroxymethyl derivative, were tested with chinese hamster v79 cells in order to identify the mutagenic metabolites of benzo[a]pyrene. mutations were characterized by resistance to ouabain or 8-azaguanine. since v79 cells do not metabolize polycyclic hydrocarbons, mutagenesis w ...19761061161
the effect of insecticides on chinese hamster cell cultures.the effect of p,p'-isomers of ddt and its derivatives ddd, dde and dda on chinese hamster cells in culture was studied. at different concentrations and various times of treatment the proliferation rate was inhibited most strongly by ddd and ddt, whereas dde exhibited a markedly weaker influence. dda was the least toxic compound of the four. the cytogenetic effects were also different. again, dda induced the least damage. only enhanced gap rates but no chromosome breaks were observed. dde was mor ...1976934173
the human gene for beta glucuronidase is on chromosome 7.inconsistent assignments of the human gene for beta glucuronidase (gus) to chromosomes 7 and 9 have previously been reported. in this study, we have correlated the expression of human gus in 22 primary chinese hamster/human hybrid lines with quantitative cytogenetic analysis. eight hybrids were positive for human gus as manifested by a five-band pattern on electrophoresis. all of them contained a human chromosome 7 in 34% or more of cells, and seven of them had not retained chromosome 9. one hyb ...1976941903
metaphase chromosome anomaly: association with drug resistance and cell-specific products.large, homogeneously staining chromosome regions which lack the longitudinal differentiation ordinarily revealed by cytogenetic "banding" methods have been found in antifolate-resistant chinese hamster cells and also in human neuroblastoma cells established in vitro. the drug-resistant cells are characterized by excessive production of the target enzyme, dihydrofolate reducatase, while the human neuroblastoma cells have phenotypes of normal neuronal cells. the homogeneously staining region appea ...1976942798
profiles of brain glycosidase activity in cuprizone-fed syrian hamsters and in scrapie-affected mice, rats, chinese hamsters and syrian hamsters. 1976943426
surface polypeptides of the chinese hamster ovary cell; an immunochemical study.antibodies elicited by the injection of live chinese hamster ovary cells (cho) into rabbits precipitated four major components from detergent extracts of cho membranes. the four components, of molecular weights 200000, 125000, 95000 and 41000 daltons, corresponded to cell surface components identified by the lactoperoxide surface label technique.1976944075
somatic cell chromosome interconnections in trypan preparations of chinese hamster testicular cells. 1976944637
articular cartilage of diabetic chinese hamsters.investigations were carried out in order to determine whether animals with spontaneous diabetes are prone to develop skeletal lesions comparable to those found in diabetic human subjects. the present report deals with the ultrastructure of the cartilage of the hip joint of diabetic chinese hamsters and nondiabetic control animals. in the diabetic animals, chondrocytes of the femoral head showed atrophy of the endoplasmic reticulum, bizarre mitodhoncria, and huge lipid inclusions, which are chang ...1976946390
behavioral development in three hamster species.the preweaning behavioral development was compared in 3 hamster species: the golden (mesocricetus auratus), chinese (cricetulus griseus), and djungarian (phodopus sungorus). differences in the age of appearance of action patterns could not be summarized by simply ranking species on either precocity or developmental speed, nor were they eliminated by measuring age from conception. problems in the interpretation of species differences in the age of appearance of action patterns are discussed.1976955290
selective isolation of reversible cold sensitive variants from chinese hamster ovary cell cultures.variants of the chinese hamster ovary cell line cho-ki (attcccl61)which grow almost normally at 38.5c but very poorly or not at all at 30c were obtained after treatment with mutagens and application of an indirect selection procedure. two kinds of variants were recovered. in the first of these, the cold sensitive phenotypw is expressed completely only at low cell densities. at higher cell desity, growth continues at the nonpermissive temperature, but at a reduced rate. in the second class, t ...1976956283
significance of dimers to the size of newly synthesized dna in uv-irradiated chinese hamster ovary cells.dna synthesized after uv irradiation is smaller than that in unirradiated cells even when pulse-labeling times are increased to compensate for the overall reduction in the rate of dna replication. by isolating newly replicated dna, incubating it with dimer-specific endonuclease from micrococcus luteus, and analyzing it on alkaline sucrose gradients, we have been able to demonstrate that this dna is synthesized in segments corresponding in size to the interdimer distance on the parental strand. i ...1976963196
cytogenetic effects of mutagens/carcinogens after activation in a microsomal system in vitro i. induction of chromosome aberrations and sister chromatid exchanges by diethylnitrosamine (den) and dimethylnitrosamine (dmn) in cho cells in the presence of rat-liver microsomes.a rat-liver microsomal system in vitro has been used to activate two indirectly acting carcinogens, dmn and den. on activation, both compounds were extremely potent in inducing chromosomal aberrations as well as sister chromatid exchanges in chinese hamster cells. the implications of these findings and the potential utility of this technique to detect mutagens/carcinogens are discussed.1976967188
replicative bypass repair of ultraviolet damage to dna of mammalian cells: caffeine sensitive and caffeine resistant mechanisms.replicative bypass repair of uv damage to dna was studied in a wide variety of human, mouse and hamster cells in culture. survival curve analysis revealed that in established cell lines (mouse l, chinese hamster v79, hela s3 and sv40-transformed xeroderma pigmentosum (xp)), post-uv caffeine treatment potentiated cell killing by reducing the extrapolation number and mean lethal uv fluence (do). in the do reduction as the result of random inactivation by caffeine of sensitive repair there were mar ...1976967189
human gene locations achieved by means of human-chinese hamster (cho-k1) auxotrophic cell hybridization. 1976975914
expression of human x-chromosomal markers in man-chinese hamster hybrids treated with isolated human chromosomes. 1976975919
effects of actinomycin d on cell cycle kinetics and the dna of chinese hamster and mouse mammary tumor cells cultivated in vitro.actinomycin d produces changes in the cell cycle kinetics of chinese hamster (ha1) and mouse mammary tumor cells (emt6) cultivated in vitro. there was a reduced rate of progression of the cells through s phase and a g2 arrest, the duration and degree of which were drug dose dependent. the lethal effects of the drug on the two cell lines were comparable. at the molecular level, dna single-strand breaks (true breaks and/or alkali-labile bonds) appear initially. after drug removal, the extent of di ...1976986240
hypoxia-dependent reduction of 1-(2-nitro-1-imidazolyl)-3-methoxy-2-propanol by chinese hamster ovary cells and kht tumor cells in vitro and in vivo.incubation of chinese hamster ovary cells and kht murine fibrosarcoma tumor cells in the absence of oxygen with 1-[2-14c]nitro-1-imidazolyl)-3-methoxy-2-propanol, one of the most effective radiation sensitizers of hypoxic cells, results in the preferential reduction of 1-[2-14c]nitro-1-imidazolyl)-3-methoxy-2-propanol. the radioactivity associated with the acid-insoluble precipitate from cells incubated in nitrogen is about four times higher than that of cells incubated in air. when aqueous extr ...1976986241
chromosome distribution in a23 chinese hamster fibroblasts.this study deals with a systematic chromosome position analysis of 116 anti-mitotic and hypotonic treated a23 chinese hamster cells. no chromosome or pair of chromosomes was found to be located nearer the center or the periphery of the metaphase plate than would be expected by the reference distribution. the homologous chromosomes of pair 2 lie nearer to each other but they do not form a specific angle. the same relative position was shown for the chromosome groups 1-2, 1-e1 and 2-e5 (e standing ...19761001138
biochemical and electron-microscopic evidence that the subunit structure of chinese-hamster-ovary interphase chromatin is conserved in mitotic chromosomes.biochemical and electron microscopic studies demonstrate that the subunit structure of chinese hamster ovary cell interphase chromatin is conserved in mititic chromosomes. digestion of purified chromosomes or nuclei with micrococcal nuclease produces dna in discrete size classes, as visualized by polyacrylamide gel electrophoresis, which are common to the two materials. early in digestion the dna fragments are integral multiples of a monomer approximately 177 base pairs in length, whereas after ...19761009941
human gene locations achieved by means of human-chinese hamster (cho-k1) auxotrophic cell hybridization. 19761024644
expression of human x-chromosomal markers in man-chinese hamster hybrids treated with isolated human chromosomes. 19761024646
transfer of the human x chromosome to human--chinese hamster cell hybrids via isolated hela metaphase chromosomes.evidence is presented for the uptake of the human x chromosome by human-chinese hamster cell hybrids which lack h p r t activity, following incubation with isolated human hela s3 chromosomes. sixteen independent clonal cell lines were isolated in h a t medium, all of which contained a human x chromosome as determined by trypsin-giemsa staining. the frequency of h a t-resistant clones was 32 x 10(-6) when 10(7) cells were incubated with 10(8) hela chromosomes. potential reversion of the hybrid ce ...19761027148
asynchronous dna replication and asymmetrical chromosome loss in chinese hamster-mouse somatic cell hybrids.a number of parameters were measured in a series of 12 hybrid cell clones from chinese hamster and mouse cells to test the hypothesis that asymmetrical chromosome loss may result from asynchrony in the replication of the two parental sets of chromosomes. all clones tended to lose telocentric (mouse) chromosomes with culture time, irrespective of the starting ratio of parental chromosomes, and in all clones, biarmed (hamster) chromosomes appeared to complete dna replication slightly earlier than ...19761028157
reactivation of chick erythrocyte nuclei in heterokaryons with temperature-sensitive chinese hamster cells.chinese hamster cell line k12 is temperature-sensitive for the initiation of dna synthesis. k12 cells synchronized by serum deprivation were collected in early g1(g0). heterokaryons were formed by fusing chick erythrocytes with serum-starved k12 cells through the use of uv-irradiated sendai virus. at the permissive temperature (36.5 degrees c), erythrocyte nuclei in heterokaryons enlarged, the chromatin dispersed, and erythrocyte nuclei synthesized dna at about the same time as the k12 nuclei. a ...19761028158
expression of human hypoxanthine phosphoribosyl transferase in chinese hamster cells treated with isolated human chromosomes.chinese hamster cells deficient for the enzyme hypoxanthine phosphoribosyl transferase (hprt) were incubated with isolated human metaphase chromosomes and 21 colonies were isolated in hat medium. three different types of cell lines were established from these clones. first, 4 cell lines had 10-30% of normal chinese hamster hprt activity with the same electrophoretic mobility as human hprt. this hprt activity remains detectable during at least 8 weeks of growth of the cells in nonselective medium ...19761028163
differential staining of interspecific chromosomes in somatic cell hybrids by alkaline giemsa stain.staining of chromosome preparations of chinese hamster-human hybrid cells and mouse-chimpanzee hybrids with alkaline giemsa has yielded color differentiation of the interspecific chromosomes. bicolor chromosomes, indicating apparent translocations also are observed for each of these hybrids. the specific color differences observed provide a rapid means of recognizing and aiding in the identification of the interspecific chromosomes and apparent translocations in these somatic cell hybrids.19761028166
isolation of a factor causing morphological changes of chinese hamster ovary cells from the culture filtrate of vibrio parahaemolyticus.a factor changing chinese hamster ovary cells from an oval to a spindle shape was isolated from the culture filtrate of vibrio parahaemolyticus. it was partially purified by successive column chromatographies on diethylaminoethylcellulose, diethylaminoethyl-sephadex a-25, hydroxylapatite, and sephadex g-200. this factor was separated from thermostabl direct hemolysin and was heat labile.19761033156
the production and action of interferon in chinese hamster cells.the interferon system has been investigated in primary cell cultures established from chinese hamster embryos and new born pups. interferon synthesis was induced with sindbis virus, ultraviolet inrradiated newcastle disease virus (u.v.-ndv) and with polyriboinosine acid-polyribocytidylic acid complex [poly (ri). poly (rc)]. only u.v.-ndv induced significant production of interferon, maximum amounts being produced in 'aged' cells. its apparent mol. wt. was 25000. cho-ki cells, an established line ...19761033270
[protein sh-group concentration and rna synthesis during the process of induction of proliferation in the stationary phase of cell culture growth].the dynamics of intracellular protein sh-group (psh) content was studied cytochemically in the course of stimulation of cell proliferation in stationary cultures of an established chinese hamster cell line and of human diploid embryo fibroblasts. the results were compared with the pattern of rna synthesis during the prereplicative period. in chinese hamster cells immediately after medium changing in stationary cultures there is an augmentation of psh content in parallel withe the increase in rna ...19761034987
[duration of the mitotic cycle of chinese hamster cells cultured at 30--39 degrees].the duration of the mitotic cycle (t) at temperatures of 30, 33, 36 and 39 degrees c was studied in subline 237 of chinese hamster cells with the aid of the radioautographic method. t was the least at 39 degrees c and increased with reduction of the cultivation temperature. at the temperature range of 33--39 degrees c prolongation of t and its periods was "proportional" to the temperature under study. the characteristic curve gradient of t dependence on the temperature showed a sharp change in t ...19761035117
[on the simultaneous effects of ionising radiation and chemical agents on animal cells. 1st communication. cytogenetic studies on x-rays and isonicotinic acid hydrazide in the chinese hamster, cricetulus griseus (author's transl)].in bone marrow cells of chinese hamsters enhanced chromosome damage is observed after 48 h treatment of the animals with isoniazid (inh) combined with x-rays only at much higher doses than normally applied in human therapy. compared to x-ray-induced aberration levels, 125 mg/kg inh and 50 r given simultaneously increase the number of gaps and breaks, the latter being increased over-additively. this points to an interaction between both agents. the combined treatment changes the mitotic rate of t ...19761036915
relationship between experimental results in mammals and man. ii. cytogenetic analysis of bone-marrow cells after treatment of cytembena and cyclophosphamide- cytembena combination.cytogenetic analysis and the micronucleus test of bone-marrow cells was used to study the possible extrapolation of results from experimental animals to man. cytembena was given i.p. in doses of 5, 10, 20, 40 and 80 mg/kg body wt. to wistar rats and in doses of 20, 40 and 80 mg/kg body wt. to icr mice and to chinese hamsters. five patients with various types of malignancy, so far medically untreated, received 20 mg cytembena/kg body wt i.v. a combination of cytembena and cylophosphamide was appl ...19761037016
aging changes in intervertebral discs and spondylosis in chinese hamsters.vertebrae and intervertebral discs of chinese hamsters, a species of rodents that develop spontaneous diabetes, were investigated for age-linked changes and for the occurrence of spondylosis. aging changes in the intervertebral discs were similar in diabetic and nondiabetic animals. the incidence of spondylosis was significantly increased and its onset was accelerated in the diabetic animals. the mechanisms operative in the pathogenesis of the lesions and their relation to the human disease are ...1976819318
evaluation and re-evaluation of genetic radiation hazards in man. ii. the arm number hypothesis and the induction of reciprocal translocations in man.the arm number hypothesis proposed by brewen and collagues in 1973 has been examined in the light of information thus far available from mammalian studies. in experiments with peripheral blood lymphocytes (radiation in vitro), a linear relationship between dicentric yield and the effective chromosome arm number of the species was obtained in the mouse, chinese hamster, goat, sheep, pig, wallaby and man. however, the data are not consistent with such a relationship in several primate species (ma ...1976819823
biochemical evidence of variability in the dna repeat length in the chromatin of higher eukaryotes.biochemical evidence is presented which confirms that the dna repeat length in micrococcal nuclease (spleen endonuclease, nucleate 3'-oligonucleotidohydrolase, ec 3-1-4-7) digests of chinese hamster ovary chromatin is shorter than that of rat liver chromatin [j.l. compton, r. hancock, p. oudet, and p. chambon (1976) eur. j. biochem., in press]. a survey of available cells has shown that the dna repeat length of the chromatin of higher eukaryotes varies widely. a value of 196 base pairs was found ...1976826906
confirmation of the assignment of the locus determining ada to chromosome 20 in man: data on possible synteny of ada and itp in human-chinese hamster somatic cell hybrids. 1976828861
intrachromosomal gene mapping in man: assignment of nucleoside phosphorylase to region 14cen leads to 14q21 by interspecific hybridization of cells with a t(x;14) (p22;q21) translocation.the structural gene for purine-nucleoside phosphorylase (np) has been assigned to a subregion of chromosome 14 by somatic cell hybridization of male and female cells containing the balanced translocation t(x;14) (p22;q21). peripheral lymphocytes were fused to a pseudodiploid hprt-deficient established chinese hamster cell line. 23 primary hybrid clones (10 derived from male and 13 from female cells) were isolated and maintained in hat selective medium. parallel subcultures from generations 16, 2 ...1976829289
interpretative differences in cytogenetic analyses: preliminary results of a collaborative an effort to establish some of the parameters which influence differences in interpretation of chromosome aberrations, we initiated a collaborative study with 26 different laboratories located in the u.s., canada and europe. they include government, private industry, and academic institutions. three species were selected for study which vary in chromosome number and complexity of the karyotype. these were the chinese hamster, human, and african green monkey. each metaphase was preselected and ...1976829598
effect of room fluorescent light on the deterioration of tissue culture medium.a major cause of tissue culture medium deterioration is exposure to room fluorescent light. riboflavin and tryptophan present in dulbecco's modified eagle's minimum essential medium, when exposed to light, yield toxic photoproducts responsible for loss of the ability of the medium to support clonal growth of human, mouse and chinese hamster cell lines. procedures for minimizing medium deterioration are discussed.19761244326
lack of synergistic effect between x-ray and uv irradiation on the frequency of chromosome aberrations in pha-stimulated human lymphocytes in the g1 stage.pha-stimulated human lymphocytes in the g1 stage were irradiated with uv radiation and x-rays, and the cells were analyzed for chromosomal aberrations in the first mitotic division. the frequency of dicentric chromosomes after single x-irradiation in the g1 stage was about twice the yield in the g0 stage. no increase in the yield of dicentrics was observed after combined irradiation with uv and x-rays. this is contrary to the finding for g0 lymphocytes, where a 2-fold increase of chromosome aber ...19761250244
organisation of the genes coding for 5s rna in the chinese hamster.hybridisation of iodinated mouse 5s rna with chinese hamster dna fractionated on a cscl gradient, identifies two separate dna components that hybridise with the labelled probe. one component is slightly, and one considerably heavier than the main band dna. this suggests that the gene coding for 5s rna in the chinese hamster may constitute two distinct populations differing in g + c content of their adjacent spacer regions.19761250414
selective modification of cell surface proteins and thymidine transport in hamster cells exposed to cholera toxin.the increased adherence and morphological response which occurs in chinese hamster ovary cells as a result of exposure to cholera toxin is paralleled by modification in the relative exposure of outer proteins. mild proteolysis treatment of the cells prelabeled with [3h] glucosamine reveals a markedly different kinetics of release of external glycopeptides as a result of exposure to cholera toxin. selective alterations in external tyrosyl-rich proteins can also be detected by lactoperoxidase-cata ...19761256059
a comparative analysis of the karyotypes of cricetus cricetus and cricetulus griseus.this study presents a comparison of the mitotic chromosomes of the two species of hamsters cricetus cricetus (european hamster) and cricetulus griseus (chinese hamster), which have the same chromosome number of 2n=22.--g-banding procedure reveals striking similarities in both karyotypes and gives the possibility to analyse structural changes so that two examples for robertsonian rearrangement can be observed.--a remarkable kind of difference between the two karyotypes becomes obvious after c-ban ...19761269344
isolation and properties of heat-labile enterotoxin(s) from enterotoxigenic escherichia coli.various techniques have been applied to the detection of skin reactivity associated with heat-labile escherichia coli enterotoxin in fermenter-grown cultures of enterotoxigenic strains in syncase medium and in trypticase soy broth. isolated products that were homogeneous, as determined by disc electrophoresis and sodium dodecyl sulfate gel electrophoresis, differed immunologically and in physicochemical characteristics depending on the strain and medium used, even though the products had similar ...1976768386
animal models of diabetes and obesity, including the pbb/ld mouse.diabetes mellitus occurs in many animals species. however, only a few have been utilized in systematic studies designed to answer unsolved problems associated with the disorder in man such as molecular basis, pathogenesis of the vascular and neural lesions, and the roles of diet, exercise and obesity. among the animal models available, rodents have been studied most thoroughly for a number of reasons: a) short generation time (sexually mature at about 3 mo of age, gestation time 21 days) and lif ...1976770197
inhibition of human lymphoma cell-line colony formation by lymphocytes from patients with lymphoma and cancer hospital employees.inhibition of human lymphoma cell-line colony formation (icf) was induced by peripheral blood lymphocytes (pbl) from patients with lymphoma and apparently healthy cancer hospital personnel. pbl from patients with non-lymphoma neoplasms and from normal blood bank donors did not elicit icf. icf was most marked when pbl were cocultivated for 24 hours in a ratio of 1000:i with target lymphoma cells that had been cultured for 24 hours before exposure. no significant icf was observed when target cells ...1976779948
mutagenicity and cytotoxicity of benzo(a)pyrene arene oxides, phenols, quinones, and dihydrodiols in bacterial and mammalian cells.twenty-nine benzo(a)pyrene derivatives were tested for mutagenic acitivity without metabolic activation in salmonella typhimurium strains ta98, ta100, and ta1538 and in chinese hamster v79 cells. the compounds studied included 4 arene oxides, all 12 isomeric phenols, 5 quinones, and 8 dihydrodiols. benzo(a)pyrene 4,5-oxide was the most mutagenic of the compounds tested in both the bacterial and mammalian systems. the other arene oxides [benzo(a)pyrene 7,8-, 9,10-, and 11,12-oxides] were only wea ...1976788898
mutagenicity and cytotoxicity of benzo(a)pyrene benzo-ring epoxides.four benzo-ring epoxides of the environmental carcinogen benzo(a)pyrene (bp) were tested for mutagenic and cytotoxic activity in 3 strains of salmonella typhimurium (ta1538, ta98, and ta100) and in chinese hamster v79 cells. although very unstable in aqueous solution, 7beta,8alpha-dihydroxy-0beta,10beta-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene (diol epoxide 1), with the 7-hydroxyl group on the same face of the molecule as the epoxide oxygen, was 1.5 to 4 times as mutagenic in the bacterial strain ...1976788899
mutagenicity of industrial compounds: styrene and its possible metabolite styrene oxide.styrene and its presumed metabolite, styrene oxide, were tested for their mutagenic effect on a forward mutation system of yeast and of chinese hamster cells, and on a gene-conversion system of yeast. experiments with liver microsomal preparations and host-mediated assay with yeast were also carried out. styrene oxide was mutagenic in all test systems. styrene was mutagenic only in the host-mediated assay.1976796697
the mutagenicity of benzimidazole and benzimidazole derivatives. vi. cytogenetic effects of benzimidazole derivatives in the bone marrow of the mouse and the chinese hamster.methyl benzimidazole-2-ylcarbamate (mbc) was mutagenic in mice by the micro-nucleus test. other benzimidazole derivatives, with the exception of the parent compound of mbc, benomyl, and the very closely related substance 2-benzimidazolylurea, did not produce micro-nuclei in mouse bone marrow. evidence is presented that mbc acts through inhibition of mitosis and that for this action the carbamoyl group is a necessary but not a sufficient condition. it is also demonstrated that for this particular ...1976796698
sister chromatid exchange as an assay for genetic damage induced by mutagen-carcinogens. ii. in vitro test for compounds requiring metabolic activation.sister chromatid exchanges (sce's) which are easily seen by "harlequin chromosome" techniques can be readily induced in cultured chinese hamster ovary (cho) cells by low concentrations of mutagen-carcinogens that do not require metabolic activation. if the cells are simultaneously treated with cyclophosphamide which does require metabolic activation before it becomes mutagenic, and an activating system consisting of an extract of rat liver containing microsomes (s-9 mix) then numerous sce's are ...1976796721
mutagenicity and metabolism of vinyl chloride and related compounds.the various adverse biological effects of vinyl chloride appear to be dependent upon the metabolic conversion of this compound into chemically reactive metabolites. the metabolism of vinyl chloride in mammals and in man, including the formation of monochloroacetic acid and some identified sulfur conjugates is reviewed. hepatic microsomal mixed function oxidases from rats, mice, and humans were equally effective in transforming vinyl chloride into alkylating agents in vitro. two of the enzyme rea ...1976799962
mutagenesis by simian virus 40. i. detection of mutations in chinese hamster cell lines using different resistance markers.the mutagenic action of sv40 in permanent lines of chinese hamster cells (cho-k1 and v79) was investigated with the aid of different resistance markers. the markers studied had resistance to 8-azaguanine (25 and 30 mug/ml), aminopterin (3.3--5.5x10(-3) mug/ml), colchicine (6.5 and 7.0x10(-2) mug/ml) and 5-bromodeoxyuridine (50--120 mug/ml), respectively. after virus infection the mutation frequencies were increased by one (azaguanine, aminopterin) and two (colchicine) orders of magnitude as comp ...1976184380
ultrastructural study of the adenohypophysis of the chinese hamster.the adenohypophysis of normal chinese hamsters of both sexes was examined ultrastructurally. organs were fixed by intravascular perfusion with s-collidine-buffered glutaraldehyde solution. seven types of cells were differentiated and, according to morphological characteristics, classified as (1) mammotropes, with very large (400-800 nm) polymorphous secretory granules; (2) somatotropes, either in the storage phase with numerous large, dense granules (average 300 nm), or in the hormone synthesis ...1976184639
confirmation of the assignment of the locus determining ada to chromosome 20 in man: data on possible synteny of ada and itp in human-chinese hamster somatic cell hybrids. 1976185012
chromosomal assignment of the gene for human red cell adenylate kinase (ak1) in man-chinese hamster somatic cell hybrids. 1976185020
simian virus 40 mutants carrying two temperature-sensitive mutations.five temperature-sensitive mutants of simian virus 40 containing two temperature-sensitive mutations were isolated. the double mutant of the a and d complementation groups, like the d mutants, failed to complement by conventional complementation analysis and did not induce host dna synthesis at 40 degrees c. however, under conditions that suppressed the d defect, the a:d double mutant expressed only the a defect. thus, viral dna replication dropped rapidly after this mutant was shifted from perm ...1976185417
[transmission and expression of malignancy in somatic hybrid cell lines (hamster/hamster, mouse/mouse, hamster/mouse)].various characteristics of transformation were studied in subclones isolated from a hybrid cell line obtained by fusion of two chinese hamster sub-lines having the same origin but presenting different properties, particularly in respect to heterotransplantability. different subclones were obtained by cloning on semisoft agar. transplantability, plating efficiency, agglutinability by concanavalin a and actinomycin d resistance were studied in parallel with the evolution of the karyotype to try to ...1976186142
transformation of chinese hamster embryo cells with an avian sarcoma virus ts mutant.chinese hamster embryo cells were transformed with temperature-sensitive mutant of the schmidt-ruppin strain of rous sarcoma virus-subgroup a (ts ny68s ra-a). the developed cell line elicited the morphological transformation at a permissive temperature of 35 degrees c, whereas after a shift to a non-permissive temperature of 40 degrees c the cells reverted to a normal phenotype. tests for the presence of avian sarcoma group-specific antigen showed that the antigen was not expressed both at permi ...1976186335
evolutionary trends in 18s ribosomal rna nucleotide sequences of rat, mouse, hamster and man.the large t1 ribonuclease fragments of 18s ribosomal rna from four mammalian species, rat, mouse, hamster and man, were compared by two-dimensional homochromatography fingerprinting. the nucleotide sequences of the large t1 ribonuclease fragments, polypyrimidines and polypurines which were different among the four mammalian species were determined and compared. the method used for determining nucleotide sequences utilizes 32p-labeling of oligonucleotides at their 5'-termini by polynucleotide kin ...1976188015
laboratory investigation of diarrhea in travelers to mexico: evaluation of methods for detecting enterotoxigenic echerichia coli.a laboratory investigation was conducted on cultures collected from travelers before, during, and after a trip to mexico to characterize the etiology of traveler's diarrhea. four laboratory methods for detecting enterotoxigenicity of escherichia coli were evaluated: the infant mouse assay, the chinese hamster ovary (cho) cell assay, the y1 adrenal cell assay, and the rabbit ileal loop. although a number of common enteric pathogens were identified as a cause of traveler's diarrhea, including six ...1976180047
the selection of virus-resistant chinese hamster ovary cells.we have selected chinese hamster ovary (cho) cells resistant to infection by encephalomycarditis (emc) virus. thus far, we have obtained five lines resistant to emc, all of which manifest different phenotypes. three of the five are not persistently infected with virus, while two lines produce infectious virus and grow in its presence. the nonpersistently infected lines exhibit different resistance profiles to the other viruses we have tested, and they are stable in nonselective growth conditions ...1976182382
modified 5'-nucleotides resistant to 5'-nucleotidase: isolation of 3-(3-amino-3-carboxypropyl) uridine 5'-phosphate and n2, n2-dimethylguanosine 5'-phosphate from snake venom hydrolysates of transfer rna.a procedure for the quantitative measurement of the o2'-methylnucleoside constitutents of rna has recently been developed in this laboratory (gray, m.w. can. j. biochem. 53, 735-746 (1975)). this assay method is based on the resistance of o2'-methylnucleoside 5'-phosphates (pnm) (generated by phosphodiesterase hydrolysis of rna) to subsequent dephosphorylation by venom 5'-nucleotidase (ec in the present investigation, two base-modified 5'-nucleotides, each displaying an unusual resista ...19766133
the production of chinese hamster interferon. 197611678
the electrophoretic properties and aggregation of mouse lymphoma cells, chinese-hamster fibroblasts and a somatic-cell hybrid.1. the electrophoretic mobilities of a mouse lymphoma cell, a chinese-hamster fibroblast and a somatic-cell hybrid (also fibroblastic), produced by fusion of the hamster cell and a mouse lymphoma cell, were measured at 25 degrees c over a range of ph, concentration of ca2+ ions and concentration of la3+ ions. 2. all the cells have pi at ph3.5. 3. ca2+ ions decrease the mobilities and zeta potentials of the cells to zero in the range 1-100mm. 4. la3+ ions lower the mobilities and zeta potentials ...197612752
resting state in normal and simian virus 40 transformed chinese hamster lung cells.normal cell deprived of amino acids or serum factors enter a resting state, whereas cells transformed by wild-type simian virus 40 do not. the ability to enter a resting state is temperature-sensitive (ts) in cells transformed by a tsa mutant of simian virus 40. we shown further: (i) that when complete medium is added to resting cells, the length of time until the onset of dna synthesis often exceeds the length of g1 in growing cells; (ii) that the length of this interval depends upon the condit ...1976179093
persistent reovirus infection of cho cells resulting in virus resistance.we obtained a persistently infected line of chinese hamster ovary cells by selection for resistance to reovirus infection. the cells were persistently infected by a population of viruses that were (i) cytopathic for parental chinese hamster ovary cells and (ii) similar to wild-type reovirus in molecular characteristics. the growth rate, plating efficiency, and morphology of the cells were altered. a large majority of the cells in the population were infected. there was no detectable interferon p ...1976176428
chromosomally depleted interspecific hybrid cell clones selected with cytotoxic antisera: utilization in the study of control of murine leukemia virus host-range.a chromosomally stable mouse-chinese hamster hybrid cell line was subjected to five rounds of selection with cytotoxic antisera raised in rabbits against either the parental mouse 3t3 cells or the parental chinese hamster wg-1 cells. routine karyological analysis of clones isolated at each stage of serum selection revealed that treatment with either serum resulted in a limited loss of chromosomes (compared to the untreated hybrid cell cultured in parallel) and that the pattern of chromosome loss ...1976176536
assignment of the ak1:np:abo linkage group to human chromosome man-chinese hamster somatic cell hybrids the segregation patterns of the loci for 25 human enzyme markers and human chromosomes were studied. the results provide evidence for the localization of the gene for adenylate kinase-1 (ak1) on chromosome 9. since the loci for the abo blood group (abo), nail-patella syndrome (np), and ak1 are known to be linked in man, the abo:np:ak1 linkage group may be assigned to chromosome 9.1976176661
simian virus 40-chinese hamster kidney cell interaction. ii. the semipermissivity of the cell system.throughout in vitro passages, chinese hamster kidney (chk) cells progressively lost susceptibility to sv 40 virus infection while remaining continuously susceptible to viral dna infection. upon infection with sv 40 virus or viral dna, the chk cell line supported viral dna and virus replication at a low level. sv 40 transformed chk cell lines spontaneously produced small amounts of viral dna and virions. the percentage of virus-producing cells was low. various clones derived from each of these li ...1976176967
enhanced sv 40-virus replication in chinese hamster kidney cells pretreated with 5-iodo-2'-deoxyuridine.sv40 virion production was enhanced when semipermissive chinese hamster kidney cells were treated with 5-iodo-2'-deoxyuridine (iudr), prior to infection either with virus or viral-dna. pretreatment did not increase sv40 replication in fully permissive monkey kidney and nonpermissive syrian hamster or mouse embryo cells.1976176975
induction by short-chain fatty acids of alkaline phosphatase activity in cultured mammalian cells.short-chain fatty acids, such as propionic, n-butyric, n-butyric, n-valeric, isovaleric, n-caproic, and n-caprylic acids, induce alkaline phosphatase activity in cultured mammalian cells. long-chain fatty acids have no similar effects. with b-6 cells (mouse x chinese hamster cell hybrids), n-butyrate at 2 to 5 mm exhibits the greatest activity. induction begins exponentially about 24 hours after addition of the fatty acid and continues over 48 hours. studies on the inducing activity-structure r ...1976177433
the effects of serum concentration on the level of integration of simian virus (sv40) genome and the transformation frequency in sv40-infected chinese hamster cells. 1976174291
enterotoxin testing of escherichia coli causing epidemic infantile enteritis in the u.k.three test systems were used to study enterotoxin production by epidemic strains of escherichia coli from cases of infantile enteritis in well-documented outbreaks in the u.k. the tests used were the y1-mouse-adrenal-cell test and the chinese-hamster-ovary-cell (c.h.o.) test for the detection of heat-labile enterotoxin and the infant-mouse test for the detection of heat-stable enterotoxin. all 6 outbreaks had been studied using full serotyping techniques and the results had been published. in ea ...197655904
antisera against electrophoretically purified tubulin stimulate colchicine-binding activity.several rabbit antisera have been prepared against reduced and alkylated, electrophoretically purified tubulin isolated from chick brain. these antisera give a single precipitin line in ouchterlony double diffusion plates when tested against partially purified tubulin, and label specifically microtubule- and tubulin-containing structures, such as mitotic spindles, cilia, and vinblastine-induced crystals, in a variety of cells. the same antisera also display the unique ability to stimulate the co ...197657619
streptozotocin and renal amyloidosis in the syrian the syrian hamster, administration of the drug streptozotocin was associated with an increased incidence and severity of renal amyloidosis. some of the more severely affected animals showed a frankly nephrotic picture. although some of the diseased animals showed decreased levels of serum albumin, no other definite changes in serum proteins were noted, nor was there any evidence of glomerular immunoglobulin or immune complex deposition. none of the lesions previously found after administratio ...197659551
cell surface antigens. iv. immunological coorespondence between glycophorin and the a1 human cell surface antigen.a stable human-chinese hamster ovary cell hybrid has been produced which, in addition to the complement of chinese hamster ovary (cho-k1) chromosomes, contains only one human chromosome, no. 11. the human cell-surface antigens whose expression is controlled by human chromosome 11, and are expressed by this hybrid, have been defined as the al immunogenetic complex. although one component of this immunogenetic complex (a1) is also expressed by human red blood cells, a second component (a2) is not. ...197661843
a novel chromosome abnormality in human neuroblastoma and antifolate-resistant chinese hamster cell lives in culture.four cell lines, sk-n-sh, sk-n-mc, sk-n-be(2), and imr-32, established in vitro from tumor tissue of patients with neuroblastoma were analyzed by trypsin-giemsa banding methods. in two of the lines a large, abnormally staining chromosome region was observed. this "homogeneously staining region" (hsr) was considerably longer than any of the bands present in normal human cells and, as revealed by both g- and q-banding, stained with an intermediate intensity. it was located on chromosomes no 6, 10, ...197662055
ten model mutagens evaluated by the micronucleus test.the following ten mutagenic compounds were subjected to the micronucleus bone marrow test (mnt) in the mouse: cyclophosphamide (ctx), thiotepa (tt), vincristin (vcr), colcemid (colc), adriamycin (am), bleomycin (bm), cytosin arabinoside (ara c), 6-mercaptopurine (6-mp), methotrexate (mtx) and 5-fluorouracil (5-fu). dose-effect curves were established for all compounds. with the exception of ctx, colc and am, the drugs also were subjected to chromosome analyses on chinese hamster fibroblasts in v ...197664925
chromosomal assignment of the gene for human red cell adenylate kinase (ak1) in man-chinese hamster somatic cell hybrids. 1976192371
localization of the structural genes for hexokinase-1 and inorganic pyrophosphatase on region (pter-->q24) of human chromosome 10.concordant expression of human hexokinase-1 and inorganic pyrophosphatase was established in somatic cell hybrids between thymidine kinase-deficient chinese hamster cells and human fibroblasts carrying a translocation of the distal third of the long arm of chromosome 10 to chromosome 17. neither human hexokinase-1 nor human inorganic pyrophosphatase expression segregated concordantly with human cytoplasmic glutamic-oxaloacetic transaminase expression.197617494625
evaluation of the mutagenic potential of cyclohexylamine on spermatogonia of the chinese a cytogenetic study on the spermatogonia of chinese hamster, cyclohexylamine (neutral sulphate) was evaluated for mutagenic effects in comparison with an untreated control group and a group treated with the mutagenic compound cyclophosphamide, by assessing spermatogonial metaphases of treated chinese hamster for chromosomal structural changes. each test group comprised 8 male hamsters selected at random. approximately 100 metaphases from each animal were assessed. the doses were 5 x 150 mg cy ...1976958236
effects of actinomycin d and puromycin on colchicine-induced endoreduplication in chinese hamster cells in vitro.experiments were carried out to study the events through which the process of endoreduplication occurs after treatment with colchicine in chinese hamster cells cultivated in vitro, and to analyse the differences between the processes leading to normal mitosis and those leading to endoreduplication. chinese hamster cells (line c-125) were treated with colchicine (10(-4) m) for 1 h, in order to induce endoreduplication. before and after colchicine treatment the cultures were treated at various int ...1976954141
cell volume growth after cell cycle block with chemotherapeutic agents.the effects of various chemotherapeutic agents on the volume of chinese hamster v79 fibroblasts and murine lymphoma l5178y cells were studied by electronic volume spectroscopy. cells arrested in the division cycle by a chemotherapeutic block continued to grow in volume resulting in abnormally large cells unable to reduce their volume by cell division. this was observed in cells treated with colcemid, vinblastine, excess thymidine, hydroxyurea, ara-c, 5-fluorouracil, actinomycin-d and bleomycin, ...197658726
Displaying items 1001 - 1100 of 26566