| biological, immunological, and binding properties of recombinant mouse placental lactogen-i. | mouse placental lactogen-i (mpl-i) cdna was inserted into a eukaryotic expression vector and introduced into chinese hamster ovary cells. cell lines that secrete high concentrations of mpl-i were isolated, and this glycoprotein was purified from the cell culture-conditioned medium. recombinant mpl-i (mpl-ir) is very similar to placental mpl-i (mpl-ip) in its recognition by polyclonal antisera raised against either mpl-ip or mpl-ir, in displacing [125i]iodo-mpl-ii from binding sites on mouse live ... | 1988 | 3197641 |
| chinese hamster ovary cell mutants deficient in an anion exchanger functionally similar to the erythroid band 3. | studies in chinese hamster ovary cells demonstrate the presence of an anion exchanger, which has some of the properties of the band 3 transporter in erythrocytes. 1) extracellular chloride is a competitive inhibitor of sulfate influx and stimulates sulfate efflux, suggesting that the mechanism of uptake is so2-(4)/cl- exchange. 2) the anion exchange inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid inhibits sulfate uptake in a dose-dependent manner. half-maximal inhibition is achieved a ... | 1988 | 3198592 |
| assignment of estradiol receptor gene to mouse chromosome 10. | differences in restriction fragment lengths were detected with murine estrogen receptor cdna (clone mor-100) between chinese hamster and mouse. these were used to determine the chromosomal location of the estrogen receptor in the mouse by southern blot analysis of dnas obtained from a panel of mouse-chinese hamster somatic cell hybrids. the mouse estrogen receptor gene was localized on mouse chromosome 10. | 1988 | 3199815 |
| comparative analysis of the clastogenicity and cytotoxicity of airborne particulate matter generated during the fire at schweizerhalle on november 1, 1986. | methanol extracts from 4 pairs of airconditioner filters (one fire-exposed and one control) from various locations (a, b, c and d) at various distances from the site of the fire were examined for their capacity to induce structural chromosomal aberrations and/or cytotoxicity in chinese hamster v79 cells. extracts from 2 additional sets of 3 filters which were exposed to urban air for 3 consecutive periods of 10 or 11 days some 4 months after the fire were also tested. chromosomal aberrations wer ... | 1988 | 3200259 |
| a new cytotoxic, dna interstrand crosslinking agent, 5-(aziridin-1-yl)-4-hydroxylamino-2-nitrobenzamide, is formed from 5-(aziridin-1-yl)-2,4-dinitrobenzamide (cb 1954) by a nitroreductase enzyme in walker carcinoma cells. | walker tumour cells in vivo or in vitro are exceptionally sensitive to the monofunctional alkylating agent 5-(aziridin-1-yl)-2,4-dinitrobenzamide (cb 1954) (cobb lm et al., biochem pharmacol 18: 1519-1527, 1969). cb 1954 forms dna interstrand crosslinks in a time-dependent manner in walker tumour cells but not in non-toxically affected chinese hamster v79 cells [(roberts jj et al., biochem biophys res commun 140: 1073-1078, 1986)]. however, co-culturing chinese hamster v79 cells with walker cell ... | 1988 | 3202902 |
| chlorobenzilate-induced effects on enzyme-altered foci in rat liver and intercellular communication in rat liver wb-f344 epithelial cells. | the mouse liver carcinogen chlorobenzilate (cb), a ddt-related pesticide, was investigated for enhancement of enzyme altered foci incidence in partially hepatectomized, diethyl-nitrosamine-initiated rats. in this in vivo experiment, cb administered per os (25 or 100 mg/kg per day for 10 weeks) enhanced foci incidence at the high dose level. in order to study potential mechanisms involved, cb was investigated for inhibition of gap-junctional intercellular communication in rat liver epithelial wb- ... | 1988 | 3203334 |
| activity of 1,1,1- and 1,1,3-trichloroacetones in a chromosomal aberration assay in cho cells and the micronucleus and spermhead abnormality assays in mice. | 1,1,1- and 1,1,3-trichloroacetones (tca) result from the disinfection of municipal water supplies with chlorine, and are direct-acting mutagens in the ames/salmonella assay. the objective of this study was to further investigate the genotoxicity of these compounds in mammalian cells using an in vitro chromosomal aberration assay in chinese hamster ovary (cho) cells and the micronucleus and spermhead abnormality assays in mice. both compounds induced significant increases in structural chromosoma ... | 1988 | 3205262 |
| in vitro evaluation of the cytotoxic potential of a novel man-made fiber, calcium sodium metaphosphate fiber (phosphate fiber). | as part of a comprehensive effort to evaluate the toxicological potential of calcium sodium metaphosphate fiber (phosphate fiber), the in vitro cytotoxicity of the fiber in cultured cells was studied. two pulmonary-derived cell systems (rat alveolar macrophages, ram; rat lung epithelial cells, lec) and an established cell line (chinese hamster ovary, cho) were used. release of lactate dehydrogenase (ldh) was used as an endpoint for cytotoxicity for all three cell types. in addition, inhibition o ... | 1988 | 3209014 |
| cloning of genomic dna for tumor necrosis factor and efficient expression in cho cells. | a genomic clone for human tumor necrosis factor (tnf-alpha) was isolated using synthetic oligonucleotide probes. the genomic dna was cleaved to remove 5' regulatory sequences and cloned in a psve3 expression vector containing the sv40 early promoter. the plasmid was co-transfected with a selectable dihydrofolate reductase (dhfr) gene into dhfr-deficient chinese hamster ovary cells. efficient expression of tnf mrna was established by northern analysis. expression of tnf protein was assayed for by ... | 1988 | 3210813 |
| molecular cloning of a salmonella typhi lt-like enterotoxin gene. | diarrhoea is a common event during typhoid fever; nevertheless, the possible participation of a diarrhoea-inducing enterotoxin has not been described (roy et al., 1985). recombinant bacteriophage lambda fdc1 was isolated from a genomic library of salmonella typhi, the causal agent of typhoid fever, by screening with a probe for the b subunit gene of the heat-labile, cholera-like, escherichia coli enterotoxin (lt). lambda fdc1 codes for an enterotoxin that causes secretion in rat ileal loops, tha ... | 1988 | 3210968 |
| preparation, toxicity and mutagenicity of 1-methyl-2-nitrosoimidazole. a toxic 2-nitroimidazole reduction product. | 1-methyl-2-nitrosoimidazole (ino), the 2-electron reduction product of 1-methyl-2-nitroimidazole (ino2), was prepared by electrochemical reduction of ino2 to 2-hydroxylamino-1-methyl-imidazole (inhoh), followed by back oxidation with iodine. although stable in crystalline form, ino reacted in water, phosphate-buffered saline, and mammalian cell growth medium. half-lives for decay were determined by uv-visible spectroscopy. ino was found to be highly toxic towards chinese hamster ovary (cho) cell ... | 1988 | 3214494 |
| cytotoxicity of extracts of spices to cultured cells. | the cytotoxicity of the extracts from eight different spices used in the indian diet was determined using dalton's lymphoma ascites tumor cells and human lymphocytes in vitro and chinese hamster ovary cells and vero cells in tissue culture. alcoholic extracts of the spices were found to be more cytotoxic to these cells than their aqueous extracts. alcoholic extracts of several spices inhibited cell growth at concentrations of 0.2-1 mg/ml in vitro and 0.12-0.3 mg/ml in tissue culture. ginger, pip ... | 1988 | 3217263 |
| the radiobiology of 24 kev neutrons. measurement of the relative biological effect free-in-air, survival and cytogenetic analysis of the biological effect at various depths in a polyethylene phantom and modification of the depth-dose profile by boron 10 for v79 chinese hamster and hela cells. | hela human carcinoma cells and v79 chinese hamster fibroblasts have been irradiated in vitro with a beam of neutrons with a nearly pure 24 kev spectrum. the relative biological effectiveness (rbe) of the filtered neutron beam relative to 60co gamma radiation was determined by irradiation of cell cultures "free-in-air". the values obtained for the rbe at 37% survival were 5.8 +/- 0.8, at a dose of 0.69 +/- 0.06 gy for the hela cells and 3.14 +/- 1.1 at a dose of 1.09 +/- 0.091 gy for the v79 cell ... | 1988 | 3219493 |
| the hemopexin gene maps to the same location as the beta-globin gene cluster on human chromosome 11. | using human hemopexin cdna clones isolated from lambda gt11 cdna library as probes, we have carried out southern blot analysis of a series of human-chinese hamster somatic cell hybrids containing different combinations of human chromosomes. synteny analysis revealed 100% concordance between the hemopexin gene and human chromosome 11. in situ hybridization of 3h-labeled hemopexin cdna to metaphase chromosomes prepared from human lymphocytes further localized the gene to the region p15.4-p15.5, th ... | 1988 | 3220477 |
| chromosome instability associated with human alphoid dna transfected into the chinese hamster genome. | repetitive dna sequences have been implicated in the mediation of dna rearrangement in mammalian cells. we have tested this hypothesis by using a dihydrofolate reductase (dhfr) expression vector into which candidate sequences were inserted. dhfr- chinese hamster ovary (cho) cells were transfected with this vector, the amplification of which was then selected for by methotrexate (mtx) exposure. cells transfected with the vector alone (and resistant to 0.02 or 1.0 microm mtx) or with a poly(dg-dt) ... | 1988 | 3221860 |
| the lack of genotoxicity of sodium fluoride in a battery of cellular tests. | in a comprehensive assessment of genotoxicity, sodium fluoride was evaluated in a battery of cellular tests providing different genetic end points and biotransformation capabilities. the tests included the following: rat hepatocyte primary culture/dna repair assay, salmonella typhimurium histidine locus reversion assay, adult rat liver epithelial cell/hypoxanthine guanine phosphoribosyl transferase mutation assay, and sister chromatid exchange in two target cell types, human peripheral blood lym ... | 1988 | 3233530 |
| a simple method for reconstitution of cho cell and human fibroblast acyl coenzyme a: cholesterol acyltransferase activity into liposomes. | a new method for reconstituting acyl coenzyme a: cholesterol acyltransferase (acat) activity from either chinese hamster ovary (cho) or human fibroblast cell extracts into cholesterol-phosphatidylcholine liposomes is described. the method is rapid (less than 60 min) and easy to perform. the procedure involves solubilizing the cell extracts with deoxycholate followed by dilution into preformed liposomes. ficoll gradient analysis demonstrated that, after reconstitution, almost all of the detectabl ... | 1988 | 3244018 |
| transformation of uv-hypersensitive chinese hamster ovary cell mutants with uv-irradiated plasmids. | transfection of uv-hypersensitive, dna repair-deficient chinese hamster ovary (cho) cell lines and parental, repair-proficient cho cells with uv-irradiated phaprt-1 or psv2gpt plasmids resulted in different responses by recipient cell lines to uv damage in transfected dna. unlike results that have been reported for human cells, uv irradiation of transfecting dna did not stimulate the genetic transformation of cho recipient cells. in repair-deficient cho cells, proportionally fewer transformants ... | 1988 | 3257945 |
| purification and characterization of natural and recombinant human plasminogen activator inhibitor-1 (pai-1). | human plasminogen activator inhibitor-1 (pai-1) was purified from the conditioned medium of endotoxin-stimulated umbilical vein endothelial cell cultures by combinations of zinc-chelate-sepharose chromatography, gel filtration on sephacryl s-300 and immunoadsorption on an insolubilized murine monoclonal antibody (ma-7d4). the final product was obtained with a recovery of approximately 20% from conditioned medium containing about 3 micrograms/ml pai-1. the yield of pai-1 was 15-100 micrograms/umb ... | 1988 | 3261688 |
| abnormal intracellular sorting of o-linked carbohydrate-deficient interleukin-2 receptors. | the synthesis and intracellular sorting of the interleukin-2 (il-2) receptor were studied with a line of mutant chinese hamster ovary (cho) cells with a reversible defect in protein o glycosylation. under normal culture conditions the mutant ldld cannot add n-acetylgalactosamine (ga1nac) to proteins. ga1nac is the first sugar of mucin-type o-linked oligosaccharides attached to protein. this o-glycosylation defect is rapidly corrected when ga1nac is added to the culture mediu. an expression vecto ... | 1988 | 3264879 |
| medium-scale ligand-affinity purification of two soluble forms of human interleukin-2 receptor. | recombinant technology has facilitated the production of two soluble forms of human interleukin-2 receptor (il-2r) in chinese hamster ovary cells. we have developed a ligand-affinity method for the medium-scale purification of these two il-2rs, based on the biochemical interactions between the matrix-bound ligand (interleukin-2) and its soluble receptor. the affinity-purified il-2r is further purified by anion-exchange chromatography followed by gel filtration. this method has provided enough hi ... | 1988 | 3266215 |
| erythroid differentiation factor is encoded by the same mrna as that of the inhibin beta a chain. | we have isolated a protein that exhibits a potent differentiation-inducing activity toward mouse friend erythroleukemia (mel) cells and human k-562 cells. the protein, designated erythroid differentiation factor (edf), was found in the culture fluid of human thp-1 cells that had been treated with phorbol 12-myristate 13-acetate. edf is a homodimer with a mr of 25,000; the mr of the monomer is 15,500. cdna clones encoding the mr 15,500 subunit of edf from thp-1 libraries were isolated and sequenc ... | 1988 | 3267209 |
| identification of c-fos sequences involved in induction by insulin and phorbol esters. | we evaluated the mechanism of insulin and phorbol ester induction of the proto-oncogene c-fos in chinese hamster ovary fibroblasts stably transformed with high levels of genes expressing normal or truncated human insulin receptors. both insulin and the tumor-promoting phorbol ester phorbol 12-myristate 13-acetate (pma) induced c-fos mrna accumulation in cells expressing high numbers of normal human insulin receptors; pma but not insulin was effective in the cells expressing the mutant receptor. ... | 1988 | 3276673 |
| genotoxicity and pac analysis of particulate and vapour phases of environmental tobacco smoke. | samples of indoor air were collected from an office room (88 m3) both before smoking and during experimental smoking of 96 cigarettes by 10 persons within 6 h. the particulates were collected on glass-fibre filters and the vapour-phase compounds on xad-2 resin. the samples were extracted with acetone and analysed quantitatively for polycyclic aromatic compounds and qualitatively with gc-ms. the extracts of filters and xad-2 resins were fractionated into neutral/acidic and 2 basic (strong and wea ... | 1988 | 3278208 |
| comparison of the mutagenicity of amsacrine with that of a new clinical analogue, ci-921. | the mutagenicity of ci-921, the 4-methyl-5-(n-methyl)carboxamide derivative of the clinical antileukaemia agent, amsacrine, has been assessed using both bacterial and mammalian cells. ci-921 is distinguished from amsacrine in its high activity against some experimental tumours and is currently undergoing phase i clinical trial. like 9-aminoacridine and amsacrine, ci-921 is mutagenic to the salmonella typhimurium frameshift tester strain ta1537, but shows no sign of inducing base pair changes in ... | 1988 | 3278212 |
| somatic cell genetics and the study of cholesterol metabolism. | the regulation of cholesterol biosynthesis by extracellular cholesterol occurs both in whole animal tissue and in permanent somatic cell lines in culture. permanent mammalian cells lines, under optimized growth conditions, are easily manipulated both biochemically and genetically. the chinese hamster ovary cell line (cho-k1) is the most widely used cell line for genetic studies. cho-k1 is a pseudo-diploid mammalian cell exhibiting a short doubling time and a relatively high plating efficiency. s ... | 1988 | 3278736 |
| characterisation of two differently processed forms of human recombinant factor ix synthesised in cho cells transformed with a polycistronic vector. | a stable transformed cell line constitutively expressing human factor ix has been established. wild-type chinese hamster ovary cells (cho cells) were transformed using a polycistronic expression vector carrying a previously isolated factor ix cdna and a selection gene encoding the escherichia coli xanthine-guanine phosphoribosyl transferase. one clone, cho 622.4, contains a high number of genomically integrated plasmids and secretes 1-3 mg factor ix l-1 day-1 into the culture medium with a biolo ... | 1988 | 3280312 |
| trial of a new acellular pertussis vaccine in healthy adult volunteers. | immunogenicity and reactogenicity of a new acellular pertussis vaccine were tested in healthy adults. the vaccine contained three constituents of bordetella pertussis; filamentous haemagglutinin, pertussis toxin (pt) and fimbriae bearing agglutinogens 2 and 3. the constituents were separately purified, treated with formaldehyde and combined with one of two aluminium adjuvants. subjects received one dose of vaccine or an appropriate adjuvant-only preparation and were monitored for clinical respon ... | 1988 | 3281387 |
| phototherapeutic, photobiologic, and photosensitizing properties of khellin. | khellin, whose chemical structure closely resembles that of psoralen, is reported to be an efficient drug for treating vitiligo when combined with ultraviolet a irradiation. photobiological activity on yeast is found to be much lower than that of bifunctional psoralens such as 5-methoxypsoralen. in vitro experiments reveal that khellin is a poor photosensitizer. it behaves as a monofunctional agent with respect to dna photoaddition. it does not photoinduce cross-links in dna in vitro or in chine ... | 1988 | 3283251 |
| effects of benzamidine derivatives on ha-ras-1 mrna accumulation in a chinese hamster cell line transformed with the activated human t24 ha-ras-1 oncogene. | tetra benzamidine derivatives were found to inhibit proteinase activity, cell proliferation and accumulation of the ha-ras-1 mrna in the fho6t1-1 chinese hamster cell line, transformed with the activated human t24-ha-ras-1 oncogene. di- and tri-benzamidine derivatives were also found to be potent inhibitors of proliferation of fho6t1-1 cells. these latter compounds could be proposed as useful substrates in the synthesis of drug-conjugated monoclonal antibodies or growth factors. | 1988 | 3284453 |
| immunoaffinity purification of human prorenin produced in chinese hamster ovary cells. | a simple immunoaffinity column chromatographic procedure is described whereby recombinant human prorenin secreted from chinese hamster ovary cells may be isolated in a high state of purity from serum-free culture medium. prorenin thus purified has been characterized by sds-polyacrylamide gel electrophoresis and by partial sequence analysis which has revealed the expected n-terminal sequence. trypsin treatment gives rise to renin, and reversible acid activation has also been demonstrated for the ... | 1988 | 3284527 |
| expression of the mouse lactate dehydrogenase-a promoter fused with the bacterial gpt gene in chinese hamster ovary cells. | the promoter region of the cloned mouse lactate dehydrogenase-a gene was fused with the gpt gene of escherichia coli, and this fusion gene was shown to express in chinese hamster ovary cells. this result demonstrates that the cloned ldh-a promoter is indeed functional. | 1988 | 3284773 |
| an evaluation of the genotoxic potential of glyphosate. | the potential genotoxicity of glyphosate, the active ingredient in roundup herbicide, was tested in a variety of well-established in vitro and in vivo assays including the salmonella typhimurium and escherichia coli wp-2 reversion assays, recombination (rec-assay) with bacillus subtilis. chinese hamster ovary cell gene mutation assay at the hypoxanthine/guanine phosphoribosyl transferase gene locus, hepatocyte primary culture/dna repair assay, and in vivo cytogenetics assay in rat bone marrow. n ... | 1988 | 3286348 |
| animal cell lysosomes rapidly exchange membrane proteins. | the lysosome has been chosen as a model to study the exchange of native membrane proteins within an organelle population. heterologous lysosomes were brought together by vesicular stomatitis virus-mediated cell fusion. the distribution of lysosomal membrane protein was visualized by indirect immunofluorescence using species-specific monoclonal antibody. lamp-2, a mouse lysosomal membrane protein, and hlamp-b, a human lysosomal membrane protein, were found to transfer to chinese hamster ovary cel ... | 1988 | 3287378 |
| differential potency and trans-activation of normal and mutant t24 human h-ras1 gene promoters. | we have employed a short-term transfection assay system in which we monitored the transient expression of the chloramphenicol acetyltransferase (cat) gene linked to the promoter region of the normal and mutant t24 h-ras1 gene or the human epsilon-globin gene in chinese hamster lung (chl) cells or cells derived from them which carry and express one or the other of the polyoma virus early genes. our findings can be summarized as follows: (i) the mutant t24 h-ras1 promoter region behaves as a stron ... | 1988 | 3288499 |
| carcinogenicity and genotoxicity of the herbicide 2,4,5-trichlorophenoxyethanol (tcpe) contaminated with dioxin. | in an earlier study 2,4,5-trichlorophenoxythanol (tcpe) contaminated with dioxin, a component of the hungarian herbicide buvinol, was found to be hepatocarcinogenic. in the present work, the hepatocarcinogenicity of tcpe was compared to its possible genotoxicity in vitro, using the salmonella/microsome test for mutagenicity and for its dna-damaging effect, the induction of sister chromatid exchanges (sce) in chinese hamster cells in vitro. it was found that purified tcpe (with 0.1 ppm dioxin con ... | 1988 | 3291725 |
| characterization of recombinant human prorenin and renin. | a cell line that secretes substantial quantities of recombinant human prorenin was prepared by transfecting chinese hamster ovary cells with a gene encoding preprorenin. the prorenin was purified to homogeneity and was found to have a single amino terminus, reflecting cleavage after a typical 23 amino acid signal sequence. the purified inactive prorenin was not a substrate for active renin and was not capable of self-activation. prorenin could be converted to renin by addition of exogenous prote ... | 1988 | 3292415 |
| temperature-sensitive chinese hamster cell mutant with a defect in glycoprotein synthesis: accumulation of the egf receptor in the endoplasmic reticulum and the role of the glucose-regulated protein grp78. | a temperature-sensitive mutant of chinese hamster fibroblasts with a defect in glycoprotein synthesis is investigated after transfection and amplification of the gene for the human egf receptor. we demonstrate that at the nonpermissive temperature a partially glycosylated species of the receptor accumulates in the endoplasmic reticulum. the oligosaccharides present are the high mannose types, since they can be removed completely by treatment with endoglycosidase h. pulse-chase experiments show t ... | 1988 | 3294237 |
| folding and activation of recombinant human prorenin. | in vitro folding of mature renin, prorenin, and fused prorenin, all produced in denatured form in inclusion bodies in recombinant escherichia coli, has been studied in order to evaluate the importance of prosequence in the folding of human renin. these studies have been compared with the in vivo folding and subsequent in vitro activation of recombinant human prorenin secreted by a nonbacterial expression system, namely chinese hamster ovary (cho) cells grown in serum-free medium. it is concluded ... | 1987 | 3297099 |
| a method for nucleic acid hybridization to isolated chromosomes in suspension. | a procedure was developed to provide differential fluorescent staining of metaphase chromosomes in suspension following nucleic acid hybridization. for this purpose metaphase chromosomes were isolated from a chinese hamster x human hybrid cell line. after hybridization with biotinylated human genomic dna, the human chromosomes were visualized by indirect immunofluorescence using antibodies against biotin and fluoresceine-isothiocyanate-(fitc)-labeled second antibodies. this resulted in green flu ... | 1987 | 3297999 |
| heterologous transmembrane signaling by a human insulin receptor-v-ros hybrid in chinese hamster ovary cells. | a hybrid receptor molecule composed of the extracellular ligand-binding domain of the human insulin receptor and the transmembrane and cytoplasmic (protein-tyrosine kinase) domains of the chicken sarcoma virus ur2 transforming protein p68gag-ros has been constructed and expressed in chinese hamster ovary (cho) cells. the hybrid is processed normally into alpha and hybrid beta subunits, is expressed on the cell surface at high levels, and binds insulin with near-wild-type affinity. furthermore, i ... | 1987 | 3299376 |
| gene for m1 subunit of ribonucleotide reductase is amplified in hydroxyurea-resistant hamster cells. | the hydroxyurea-resistant chinese hamster cell line 600h has been shown to have greatly elevated quantities of ribonucleotide reductase. this increase in enzyme activity is due to an increased level of both the m1 and m2 subunit activities. the m1 subunit has been purified from the 600h cell line and shown to consist of a series of six protein spots with apparent molecular weights of 88,000 daltons, but with varying isoelectric points in the range of ph 6.5-7.0. western blot analyses with antise ... | 1987 | 3299747 |
| assembly and turnover of detyrosinated tubulin in vivo. | detyrosinated (glu) tubulin was prepared from porcine brain and microinjected into human fibroblasts and chinese hamster ovary (cho) cells. glu tubulin assembled onto the ends of preexisting microtubules and directly from the centrosome within minutes of its microinjection. incorporation into the cytoskeleton continued until almost all of the microtubules were copolymers of glu and tyrosinated (tyr) tubulin. however, further incubation resulted in the progressive and ultimately complete loss of ... | 1987 | 3301867 |
| differential expression of mouse embryonic antigens tec-1 and tec-2 in the epididymis of four rodent species. | the expression, properties and relationship of two mouse embryonic antigens (tec-1 and tec-2), which are defined by monoclonal antibodies, were investigated in the epididymis of four rodent species. absorption analysis, indirect immunofluorescence microscopy and immunohistochemistry revealed that all the species studied contained in their epididymides, but not in testes, either tec-1 (chinese hamster), tec-2 (guinea pigs, rats) or both tec-1 and tec-2 (mice) antigens. in an indirect immunofluore ... | 1987 | 3304664 |
| marker exchange mutagenesis of the aerolysin determinant in aeromonas hydrophila demonstrates the role of aerolysin in a. hydrophila-associated systemic infections. | we report here on the isolation of isogenic strains of aeromonas hydrophila ab3 deleted for a segment of the aerolysin gene. all aer mutants obtained lacked the 49-kilodalton aerolysin gene product and were neither hemolytic for blood erythrocytes nor cytotoxic for chinese hamster ovary tissue culture cells. one such mutant, ab3-5, was used in a mouse toxicity model to evaluate the role of aerolysin in the pathogenesis of a. hydrophila infections. the strain had a 50% lethal dose (ld50) of great ... | 1987 | 3305370 |
| low binding capacity and altered o-linked glycosylation of low density lipoprotein receptor in a monensin-resistant mutant of chinese hamster ovary cells. | we have studied function and structure of the low density lipoprotein (ldl) receptors in a monensin-resistant (monr-31) mutant isolated from chinese hamster ovary (cho) cells. to assay the ability of the receptor to bind ldl, we employed three methods, 125i-ldl binding to the cells at 4 degrees c, 125i-ldl binding to the receptor-phospholipid complex (schneider, w.j., goldstein, j.l., and brown, m.s. (1980) j. biol. chem. 255, 11442-11447), and ligand blotting (daniel, t.o., schneider, w.j., gol ... | 1987 | 3308876 |
| metabolic activation to a mutagen of 3-hydroxy-trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene, a secondary metabolite of benzo[a]pyrene. | 3-hydroxy-trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene (3-oh-bp-7,8-diol) was isolated from arylsulfatase/beta-glucuronidase-treated bile of rats to which 3-hydroxybenzo[a]pyrene (3-oh-bp) has been administered. this triol was investigated for mutagenicity in salmonella typhimurium (reversion to histidine prototrophy of strains ta 97, ta 98, ta 100 and ta 1537) and in v79 chinese hamster cells (acquisition of resistance to 6-thioguanine). when no exogenous metabolizing system was added the trio ... | 1987 | 3311446 |
| establishment of a human/chinese hamster hybrid clone panel. | combined with the chromosome g-banding, followed by giemsa-11 techniques and chromosomal marker isozyme analysis, 6 out of 200 subclones have been analyzed in detail. a primary hybrid clone panel has been established, which can be used to map genes on chromosomes 4, 5, 8, 12, 20 and 22. since the panel contains deleted chromosomes 4, 5, 8 and 12, genes on these chromosomes can be mapped regionally. | 1987 | 3313724 |
| mutagenic and clastogenic properties of 3-chloro-4-(dichloromethyl)-5-hydroxy-2 (5h)-furanone: a potent bacterial mutagen in drinking water. | 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5h)-furanone (mx) was found to be a direct-acting mutagen in the ames test for strains ta1535, ta1538, ta92, ta97, ta98, ta100 and ta102. the highest mutagenic response (approximately 13,000 revertants/nmol) was seen in strain ta100. the ta100 response was six- to tenfold higher than in ta98, ta97, and ta102, and 100- to 500-fold higher than in ta1535, ta92, and ta1538. the addition of a 9,000 x g supernatant fraction (s-9) from livers of polychlorinated b ... | 1987 | 3315659 |
| genotoxic effects of glycidyltrimethylammonium chloride. | evaluation of the genotoxicity of epoxides is best carried out on a case by case basis. although glycidyltrimethylammonium chloride (gtac) is widely used in several industrial applications, its genotoxicity is poorly documented. therefore, we have evaluated gtac in a battery of 4 in vitro short-term tests for genotoxicity. we report here that gtac mediates the induction of base-pair substitutions in s. typhimurium, gene conversion in s. cerevisiae (d7), chromosomal aberrations in cho cells and v ... | 1987 | 3317031 |
| functional expression of the cdna encoding for human lactate dehydrogenase-a in chinese hamster ovary cells. | the cloned cdna encoding for human lactate dehydrogenase-a was inserted immediately downstream to the sv40 early promoter, and it was shown to synthesize the human ldh-a polypeptide in chinese hamster ovary cells. the human ldh-a subunit and the endogenous chinese hamster ldh-a subunit formed in vivo a heterotetrameric ldh-a3a1 functional isoenzyme, indicating the conserved tertiary structure of both ldh-a subunits. | 1987 | 3319193 |
| chromosome aberrations and sister chromatid exchanges in chinese hamster ovary cells: evaluations of 108 chemicals. | results from the testing of 108 coded chemicals in chinese hamster ovary (cho) cells for the induction of chromosome aberrations and sister chromatid exchanges (sces) are presented. all chemicals were tested with and without exogenous metabolic activation, using protocols designed to allow testing up to toxic doses. cell harvest times could also be extended if chemical-induced cell cycle delay was seen. chromosome aberrations were induced by 43 of the chemicals, and 66 induced sces; 37 of the ch ... | 1987 | 3319609 |
| mitochondrial binding of a protein affected in mutants resistant to the microtubule inhibitor podophyllotoxin. | specific antibodies to a protein p1 mr approximately equal to 63,000) from chinese hamster ovary cells, which is affected in mutants resistant to the microtubule inhibitor, podophyllotoxin, and behaves like a microtubule-related protein by certain criteria [14], have been raised. the antibody reacts specifically with the p1 protein in one- and two-dimensional immunoblots, and a cross-reacting protein of similar molecular mass and electrophoretic mobility is also found in cells from various verte ... | 1987 | 3319627 |
| genetic analysis of tumorigenesis: a conserved region in the human and chinese hamster genomes contains genetically identified tumor-suppressor genes. | regional chromosome homologies were found in a comparison of human 11p with chinese hamster 3p. by use of probes that recognize six genes of human 11p (ins, cat, hbbc, calc, pth, and hras), the corresponding genes were localized by in situ hybridization on chinese hamster chromosome 3. ins and cat were located close to the centromere on 3p, whereas hbbc, calc, and pth were at 3q3-4 and hras at 3q4. extensive prior data from chromosome studies of tumorigenic and tumor-derived chinese hamster cell ... | 1987 | 3321067 |
| etoposide (vp16) and teniposide (vm26): novel anticancer drugs, strongly mutagenic in mammalian but not prokaryotic test systems. | the mutagenic effect of the antineoplastic drugs vp16 (etoposide; 4'-demethylepipodophyllotoxin-ethylidene-beta-d-glucopyranoside) and vm26 (teniposide; 4'-demethylepipodophyllotoxin-thenylidene-beta-d-glucopyr ano side) in mammalian and prokaryotic test systems have been compared. both vp16 and vm26 which interact with mammalian dna topoisomerase ii, are strongly mutagenic in chinese hamster ovary cells as indicated by the induction of mutations at the hypoxanthine-guanine phosphoribosyl transf ... | 1987 | 3325741 |
| mutagenicity of extracts of brown and black masheri, pyrolysed products of tobacco using short-term tests. | black and brown varieties of masheri, which are pyrolysed tobacco products were analysed for their mutagenic potentials using a battery of test systems. both materials were found to be mutagenic in salmonella typhimurium strain ta98 with metabolic activation and also in v79 chinese hamster cells producing 8-azaguanine resistant mutations. both varieties were found to induce statistically significant increases in micronuclei formation as compared to those produced in the solvent controls. both va ... | 1987 | 3325755 |
| new evidence for the presence of chromosomes in micronuclei of human and chinese hamster cells. | the aim of this work was to demonstrate the presence of intact chromosomes in micronuclei. such evidence was based on the re-expression of metaphase chromosomes by micronuclei fused with whole cells. three different experimental approaches were used; they differed only in the criteria used to discriminate between the chromosomes of micronuclear origin and those present in the cell to which micronuclei were fused. these methods involved the expression of: (a) human chromosomes in mouse cells, (b) ... | 1987 | 3325767 |
| the toxicity and mutagenicity of the anti-tumour drug 5-aziridino-2,4-dinitrobenzamide (cb1954) is greatly reduced in a nitroreductase-deficient strain of e. coli. | in the 1970s it was shown that the monofunctional alkylating agent cb1954 (5-aziridino-2,4-dinitrobenzamide) kills the walker rat carcinoma 256 in vivo and in vitro, but is inactive against several other tumours. in studies with bacteria, the large differences in survival in dna-repair-proficient and deficient strains of escherichia coli b treated with cb1954 were characteristic of a difunctional cross-linking agent. it was concluded that dna was the only target large enough to receive significa ... | 1987 | 3325769 |
| methods of analysis of data on mitotic aneuploidy. | the induction of aneuploidy in cultured mammalian cells has been studied using two chemical agents, diethylstilboestrol dipropionate and colcemid, which act on the mitotic spindle, in order to investigate different methods of scoring and statistical analysis. two cell lines, one human and the other chinese hamster, were each exposed to one test agent, and metaphase preparations scored (a) counting all the chromosomes and (b) counting only the chromosomes of a selected group within the karyotype, ... | 1987 | 3325770 |
| [characteristics of the ultrastructural organization of the nuclei of somatic cell hybrids]. | a study was made of the ultrastructure of cell nuclei of two types of hybrid clones obtained from the fusion of chinese hamster with human skin fibroblasts, and from that of mouse hepatoma cells with mink fibroblasts. in cell nuclei of the eight hybrid clones deep invaginations of the inner membrane, not characteristic of the parent cells, were revealed. analysis of serial sections, and application of electron microscopic radioautography and histochemistry have suggested that these structures ar ... | 1987 | 3327213 |
| interleukin 3 like activity secreted from human ras or myc transfected rodent cells. | we have examined the secretion of il-3 like activity from recipient normal mouse, rat and chinese or syrian hamster cells and their derivative cell lines obtained after transfection with recombinant plasmids carrying an exogenous human ras or myc gene. il-3 like activity was determined by two cell proliferation assays which employed the fdc-p1 and 32d il-3 dependent mouse cell lines. the colorimetric mtt assay, where a tetrazolium salt is employed, and the trypan blue dye exclusion assay were us ... | 1987 | 3327454 |
| genotoxicity of compounds from cooked beef in repair-deficient cho cells versus salmonella mutagenicity. | a series of compounds isolated on the basis of their mutagenicity in the ames/salmonella reversion assay were previously identified in fried beef and chemically synthesized for further evaluation. in this study three of these compounds were tested for genotoxic effects in the uv5 line of chinese hamster ovary (cho) cells, which is deficient in nucleotide excision repair. both 2-amino-3,4-dimethyl-imidazo]4,5-f]quinoline (meiq) and 2-amino-3,8-dimethyl-imidazo[4,5-f]quinoxaline (meiqx) gave very ... | 1987 | 3328038 |
| protection of chinese hamster cells against the cytotoxic and mutagenic effects of alkylating agents by transfection of the escherichia coli alkyltransferase gene and a truncated derivative. | the cytotoxic and mutagenic effects of various monofunctional and bifunctional alkylating agents have been assessed in v79 chinese hamster cells that express either the entire o6-alkylguanine (o6ag) and alkylphosphotriester alkyltransferase (atase) gene (clone 8 cells) or a truncated form that codes only for o6ag atase activity (clone sb cells). protection ratios, as determined by d37 values, were greater for clone 8 cells than for sb cells. significant protection against the mutagenic effects o ... | 1987 | 3328039 |
| isolation and characterization of native human renin derived from chinese hamster ovary cells. | transfection of chinese hamster ovary (cho) cells with a plasmid containing the cdna for human preprorenin has provided cell lines that secrete 15 mg of native prorenin per liter of culture medium. tryptic activation of the prorenin occurs by selective cleavage of the arg66-leu67 bond (numbering as in preprorenin). the renin product, purified in a single step and in high yield by affinity chromatography, is fully stable for as long as 8 months when stored in solution at 4 degrees c and ph 6.5. p ... | 1986 | 3329727 |
| genotoxic activities of 2-nitronaphthofurans and related molecules. | the genotoxic activities of 63, 2-nitronaphthofurans and related molecules were examined using two bacterial short-term tests, the salmonella mammalian microsome assay test or mutatest, a mutagenesis assay, and/or the sos chromotest, an assay for induction of an sos function in escherichia coli. seven compounds were also investigated in the chinese hamster ovary cells/hypoxanthine-guanine phosphoribosyl transferase (cho/hgprt) test, a mammalian gene mutation assay. our main conclusions are the f ... | 1986 | 3331663 |
| genotoxicity and polynuclear aromatic hydrocarbon analysis of environmental tobacco smoke samples from restaurants. | acetone-extracted samples of airborne particulate matter collected in three restaurants were analysed for their content of polynuclear aromatic hydrocarbons (pah) and related polynuclear aromatic compounds (pac) as well as for genotoxic activity using the salmonella/microsome assay (strains ta98 and ta100) and sister chromatid exchange (sce) induction in chinese hamster ovary (cho) cell cultures. the total particulate matter varied considerably in the restaurants, being 1.37 mg/m3 at the highest ... | 1986 | 3331668 |
| the induction of dna adducts in mammalian cells exposed to 1-nitropyrene and its nitro-reduced derivatives. | 1-nitropyrene, 1-nitrosopyrene and 1-aminopyrene were investigated for their ability to induce covalently bound dna adducts in calf thymus dna and chinese hamster lung fibroblasts. xanthine oxidase catalysed the induction of one major and one minor dna adduct in 1-nitropyrene- or 1-nitrosopyrene-treated calf thymus dna, whilst 1-aminopyrene was inactive. these compounds did not form detectable dna adducts in the absence of xanthine oxidase. the major dna adduct produced by 1-nitropyrene and 1-ni ... | 1986 | 3331673 |
| species differences in mutagenicity testing. ii. sister-chromatid exchange and micronucleus induction in rats, mice and chinese hamsters treated with cyclophosphamide. | comparative investigations of sister-chromatid exchange (sce) and micronucleus induction in the bone marrow of rats, mice and chinese hamsters with the cytostatic alkylating mutagen cyclophosphamide (cp) revealed remarkable species differences in their mutagenic responses. with both test systems the sensitivities of the three species can be ranked into the order rat greater than mouse greater than chinese hamster. more explicit results were obtained with the sce test than with the micronucleus t ... | 1986 | 3331680 |
| chromosome aberrations induced by nitro-, nitroso- and aminopyrenes in cultured chinese hamster cells. | nitropyrenes are a class of polycyclic hydrocarbons that have been shown to be potent point mutagens in the salmonella/mammalian microsome assay. however, relatively few data have been published on their ability to induce chromosome aberrations. in this paper we report the cytogenetic activity of 1-nitropyrene, 1-nitrosopyrene, and 1-aminopyrene in cultured chinese hamster cells (don:wg3h). following treatment with 1-nitrosopyrene, high levels of both chromosome and chromatid types of aberration ... | 1987 | 3331690 |
| mutagenicity of procarbazine for v79 chinese hamster fibroblasts in the presence of various metabolic activation systems. | even though procarbazine is mutagenic in most in vivo systems, a number of in vitro assays failed to indicate a positive effect. since inappropriate metabolic activation in vitro is one explanation for these findings, the effects of procarbazine on v79 chinese hamster fibroblasts in the absence and in the presence of either an s9 liver homogenate or hepatocytes from male rats were evaluated. the influence of enzyme induction was studied by performing experiments using s9 and hepatocytes both fro ... | 1987 | 3331691 |
| a simple and reliable in vitro test system for the analysis of induced aneuploidy as well as other cytogenetic end-points using chinese hamster cells. | although aneuploidy is a serious human health problem, the experimental methodology devised until now to study the mechanisms involved in the induction of aneuploidy and for the screening of aneuploidy-inducing agents has not been so much employed to have the necessary validation. a procedure using primary cell cultures of chinese hamster embryo cells grown on cover glasses is described. to avoid the excessive scattering and subsequent loss of chromosomes, a hypotonic treatment with a 0.17% sodi ... | 1987 | 3331701 |
| analysis of human chromosome 11 by somatic cell genetics: reexamination of derivatives of human-hamster cell line j1. | through the fusion of a cho cell population to a human cell population, a hybrid cell line which has lost all human chromosomes except chromosome 11 was derived. this cell line, j1, does not appear to segregate human chromosome 11 during growth. a series of deletion segregants were isolated from j1 which had lost a portion of either the long, short, or both arms of chromosome 11. this panel of deletion segregants was used for mapping a number of genetic markers on the short arm of chromosome 11. ... | 1987 | 3331828 |
| cytogenetic effects induced by alkylated guanine in mammalian cells. | cytogenetic effects of o6-ethylguanine (o6etg) were investigated in v79 chinese hamster cells and human lymphocytes. the frequency of micronuclei and of polyploid cells was increased in a dose-dependent manner in v79 cells. micronuclei were larger than those induced by the alkylating agent diethylsulfate, suggesting that they originated from chromosome loss rather than from chromosome breakage. chromosome displacement was also observed and further indicated damage to the spindle. in human lympho ... | 1986 | 3333274 |
| isozymes as bioprobes for genetic analysis of nonhuman primates. | the identification and the utilization of genetically determined electrophoretic differences of enzymes between the individuals of species as well as between cell lines have played an important role in the advancement of mammalian genetics during the past quarter of a century. in an explicit search we found a number of red cell enzyme polymorphisms in each of the following four species: chimpanzees, orang utans, rhesus monkeys and brown capuchins. allelic distribution patterns among populations ... | 1987 | 3333351 |
| various short-term assays and two long-term studies with the plasticizer di(2-ethylhexyl)phthalate in the syrian golden hamster. | the plasticizer di(2-ethylhexyl)phthalate (dehp) and its main metabolite monethylhexylphthalate (mehp) were investigated in several short-term in vitro assays, including mutagenicity in salmonella typhimurium ta102, a strain sensitive to mutations arising as a cause of oxidative dna damage. also dna amplification in sv40-transformed chinese hamster cells and dna damage in rat and hamster hepatocytes were investigated. the two compounds were not genotoxic in any of the test systems. furthermore, ... | 1988 | 3335045 |
| enhancement of cytotoxicity of modeccin by nigericin in modeccin-resistant mutant cell lines. | we have isolated a chinese hamster ovary cell mutant (dmpr-2) simultaneously resistant to diphtheria toxin and modeccin. in addition to the increased resistance to these two toxins used in the selection, this mutant is more resistant to pseudomonas toxin and hypersensitive to ricin than the parental cell line. in contrast to the wild-type cells in which nigericin protects cells from modeccin, the cytotoxicity of modeccin in the dmpr-2 mutant is enhanced by nigericin. we have also studied the eff ... | 1988 | 3338496 |
| antifolate-resistant chinese hamster cells. molecular basis for the biochemical and structural heterogeneity among dihydrofolate reductases produced by drug-sensitive and drug-resistant cell lines. | nucleotide sequence analysis of a cdna clone shown to direct the synthesis in escherichia coli of a pi 6.5 form of dihydrofolate reductase (dhfr) with an apparent molecular weight of 21,000 has clarified the allelic nature of the dhfr genes present in the chinese hamster lung cell line dc-3f. by comparison with other cdnas encoding different forms of dhfr produced by these cells or by antifolate-resistant sublines derived from them (melera, p.w., davide, j.p., hession, c.a., and scotto, k.w (198 ... | 1988 | 3339001 |
| promutagen activation by vicia faba: an assay based on the induction of sister-chromatid exchanges in chinese hamster ovary cells. | plant activation of promutagens was studied using vicia faba s10 (in vitro activation) and the extracts prepared from promutagen-treated roots of vicia faba (in vivo activation). the induction of sister-chromatid exchanges in chinese hamster ovary cells was used as an endpoint to evaluate the cytogenetic effects of promutagens activated by vicia faba. cyclophosphamide and ethyl alcohol were activated both by vicia s10 and by the vicia extracts, and their activation resulted in an increase in sce ... | 1988 | 3340085 |
| chromosomal abnormalities and sister-chromatid exchange in bone marrow cells of mice and chinese hamsters after inhalation and intraperitoneal administration. ii. cyclophosphamide. | the genotoxic effects of cyclophosphamide (cpp), a human and animal carcinogen requiring metabolic activation, were studied in bone marrow cells of mice and chinese hamsters, analyzing chromosome abnormalities (ca) and sister-chromatid exchange (sce) after a 2-h inhalation or a single intraperitoneal administration. in order to compare the genotoxicity after the different routes of administration in the dose range of 10-110 mg cpp/kg body weight, the systemic dose obtained by inhalation was calc ... | 1988 | 3340088 |
| potentially lethal radiation damage repair and its inhibition by hyperthermia in normal hamster cells, mouse cells, and transformed mouse cells. | the capacity of plateau-phase chinese hamster v79 and normal and transformed c3h-10t1/2 cells for repair of potentially lethal radiation damage (pld) was evaluated for cells irradiated alone or given combined treatments of heat and radiation. the data show that all cell lines tested could repair pld and that transformation to the tumorigenic state may reduce the capacity to repair pld, especially if cells are evaluated at equal survival levels. hyperthermia treatments before irradiation produced ... | 1988 | 3340720 |
| human epithelial teratocarcinoma cells (p3): radiobiological characterization, dna damage, and comparison with other rodent and human cell lines. | survival parameters and immediate dna damage induced by 60co gamma rays, 50-kvp x rays, and janus fission-spectrum neutrons in human epithelial p3 cells (derived from an embryonic teratocarcinoma) are compared with those for chinese hamster lung v79 cells. dna damage caused by x and gamma irradiation, measured by alkaline elution methods, is the same in both cell types, whereas the p3 cells are about two times more sensitive (as measured by do ratios of the final survival curve slope) to the let ... | 1988 | 3340734 |
| effects of glucose starvation and puromycin treatment on lipid-linked oligosaccharide precursors and biosynthetic enzymes in chinese hamster ovary cells in vivo and in vitro. | previous studies from several laboratories have demonstrated that glucose-starved chinese hamster ovary (cho) cells and other cells in culture switch from synthesis of the normal glc3man9glcnac2-p-p-dol to man5-glcnac2-p-p-dol. in this study we have investigated this phenomenon in cho cells in vitro and in vivo in order to determine the possible site of this block. our results demonstrate that enzymatic activities responsible for man9glcna2 synthesis in vitro are normal in glucose-starved cells. ... | 1988 | 3341746 |
| photosensitizing effects of the tricyclic heteroaromatic cationic dyes pyronin y and toluidine blue o (tolonium chloride). | pyronin y [3,6-bis(dimethylamino)xanthylium chloride; py] and toluidine blue o [tolonium chloride; 3-amino-7-(dimethylamino)-2-methyl phenothiazin-5-ium chloride; tb] are cationic dyes commonly used in cytochemistry that have affinity to nucleic acids, predominantly to rna. in live cells these dyes accumulate in mitochondria and sensitize the cells to light. the photosensitizing effects of py and tb were compared with those of another mitochondrial cationic dye, rhodamine 123, and a noncationic ... | 1988 | 3342408 |
| genotoxic effects of paracetamol in v79 chinese hamster cells. | paracetamol was studied for possible genotoxic effects in v79 chinese hamster cells. paracetamol (0.5 mm for 30 min) reduced the rate of dna synthesis in exponentially growing v79 cells to about 50% of control. a further decrease in the dna synthesis was seen during the first 30 min after termination of paracetamol exposure. paracetamol (3 and 10 mm for 2 h) caused a small increase in dna single-strand breaks, as measured by the alkaline elution technique. after 16 h elution, the amount of dna r ... | 1988 | 3343983 |
| comparative study of the asparagine-linked sugar chains of human erythropoietins purified from urine and the culture medium of recombinant chinese hamster ovary cells. | the asparagine-linked sugar chains of human erythropoietin produced by recombinant chinese hamster ovary cells and naturally occurring human urinary erythropoietin were liberated by hydrazinolysis and fractionated by paper electrophoresis, lectin affinity chromatography, and bio-gel p-4 column chromatography. both erythropoietins had three asparagine-linked sugar chains in one molecule, all of which were acidic complex type. structural analysis of them revealed that the sugar chains from both er ... | 1988 | 3346214 |
| cytoskeleton-associated plectin: in situ localization, in vitro reconstitution, and binding to immobilized intermediate filament proteins. | the association and interaction of plectin (mr 300,000) with intermediate filaments and filament subunit proteins were studied. immunoelectron microscopy of whole mount cytoskeletons from various cultured cell lines (rat glioma c6, mouse balb/c 3t3, and chinese hamster ovary) and quick-frozen, deep-etched replicas of triton x-100-extracted rat embryo fibroblast cells revealed that plectin was primarily located at junction sites and branching points of intermediate filaments. these results were c ... | 1988 | 3346324 |
| expression of erythroid differentiation factor (edf) in chinese hamster ovary cells. | plasmid dna containing edf subunit cdna and mouse dihydrofolate reductase (dhfr) cdna was transfected into cho dhfr- cells by the calcium-phosphate method. dhfr positive transformants secreted recombinant edf (r-edf) constitutively in an active form and accumulated it in the conditioned medium. furthermore, cells which were resistant to methotrexate (mtx : 0.5 microm) secreted r-edf up to 1 microgram/ml. r-edf was identical to natural edf (n-edf) produced by human acute monocytic leukemia cell l ... | 1988 | 3348775 |
| species differences in sensitivity of nucleoside transport in erythrocytes and cultured cells to inhibition by nitrobenzylthioinosine, dipyridamole, dilazep and lidoflazine. | differences in sensitivity of uridine transport in erythrocytes and cultured cells to inhibition by dipyridamole, dilazep and lidoflazine were largely species-specific; uridine transport in human cells, and probably in pig and rabbit cells, was 2-3- and 10-times more sensitive to inhibition by dipyridamole (ic50 approx. 50 nm) and about 10- and 20-times more sensitive to dilazep inhibition (ic50 approx. 5 nm) than transport in mouse and rat cells, respectively. uridine transport in human erythro ... | 1988 | 3349106 |
| lectin-like binding of pertussis toxin to a 165-kilodalton chinese hamster ovary cell glycoprotein. | chinese hamster ovary (cho) cells cluster in the presence of pertussis toxin, a response that is correlated with the adp-ribosylation of a mr = 41,000 membrane protein by the toxin. a ricin-resistant line of cho cells (cho-15b) which specifically lacks the terminal neuac----gal beta 4glcnac oligosaccharide sequence on glycoproteins did not cluster in response to pertussis toxin. these cells do contain the mr = 41,000 protein substrate for the enzymatic activity of the toxin which suggests that p ... | 1988 | 3350815 |
| influence of dietary carrot on cytostatic drug activity of cyclophosphamide and its main directly acting metabolite: induction of sister-chromatid exchanges in normal human lymphocytes, chinese hamster ovary cells, and their dna repair-deficient cell lines. | we have utilized an in vivo drug metabolism technique (i.e. injecting the chemical into rat and isolating plasma with metabolites from blood) for detecting the genotoxicity of indirectly acting cyclophosphamide and its directly acting metabolite phosphoramide mustard in cultures of human peripheral blood lymphocytes of normal individuals, fanconi's anaemia (fa) and aplastic anaemia (aa) patients, wild-type chinese hamster ovary cells (cho) and its dna repair-deficient mutant 43-3b cells. in addi ... | 1988 | 3352640 |
| sce induction in chinese hamster ovary cells (cho) exposed to g agents. | cultured chinese hamster ovary (cho) cells were exposed to two neurotoxic organophosphates, either sarin (gbi, gbii) at 1.4 x 10(-3) m or soman (gd) at 1.1 and 2.2 x 10(-3) m for 1 h, grown and their metaphase chromosomes scored for sister-chromatid exchanges (sce). no cytotoxicity was seen with either agent at any dose level tested. since histograms of sce per cell showed that they were non-symmetrically arrayed around the mean, the number of sces were analyzed by using the nonparametric tests, ... | 1988 | 3352646 |
| mutagenic and clastogenic activity of nitracrine analogues in cultured v79 chinese hamster cells. | nitracrine is used clinically as an antitumour agent, and analogues are actively being developed in some laboratories. the mutagenic activity of 9-[(3-dimethylaminopropyl)amino]-acridine and its 1-nitro (nitracrine), 2-, 3- and 4-nitro derivatives was evaluated at the 6-thioguanine and ouabain resistance loci in cultured chinese hamster fibroblasts (v79-171b cell line). the des-nitro, 2- and 3-nitro caused no statistically significant mutagenic activity at either locus. each of these 3 compounds ... | 1988 | 3352647 |
| molecular cloning and chromosomal localization of a gene coding for human cardiac myosin heavy-chain. | a human cardiac myosin heavy-chain (mhc) gene, cloned in a charon 4a phage, was isolated using two rat cardiac pcmhc dna clones (pcmhc26: alpha-mhc type; and pcmhc5: beta-mhc type) as probes and shown to correspond to cardiac myosin heavy-chain of the alpha-type. the 4.3-kb cardiac genomic dna clone was used as a probe in the southern analysis of human genomic dna from human-chinese hamster or human-mouse somatic cell hybrids. the results show that the human cardiac mhc gene is assigned to chrom ... | 1988 | 3354609 |
| acute and neurotoxicity of two structurally related acetylenic compounds: 5,7,11-dodecatriyn-1-ol and 5,7,11,13-octadecatetrayne-1,18-diol. | two structurally related acetylenic compounds, 5,7,11-dodecatriyn-1-ol, (compound a), and 5,7,11,13-octadecatetrayne-1,18-diol (compound b), were evaluated in a tier i toxicology testing program as part of an ongoing research and development program. this battery of acute tests included acute oral, guinea pig maximization, photosensitization, dermal irritation, ames and multiple genetic endpoint and a 2 week oral fetotoxicity study. compound a was found to have an oral ld50 of 0.25 ml/kg, be an ... | 1988 | 3356863 |
| coincidental acquisition of growth autonomy and metastatic potential during the malignant transformation of factor-dependent ccl39 lung fibroblasts. | after sc implantation into balb/c nude mice, factor-dependent and premalignant chinese hamster lung fibroblasts (ccl39) developed into tumors that occasionally disseminated and produced pulmonary metastases. unlike ccl39 cells that required several growth factors (insulin, alpha-thrombin, epidermal growth factor) to proliferate in culture, metastatic tumor cells divided autonomously in serum-free medium. the re-implantation of independently isolated primary tumors revealed that they comprised fa ... | 1988 | 3357198 |
| modulation of a human dihydrofolate reductase minigene following release from amino acid deprivation involves both 5' and 3' nucleotide sequences. | a dihydrofolate reductase (dhfr) expression system composed of a dhfr minigene constructed from human dhfr genomic and cdna sequences stably transfected into dhfr- chinese hamster ovary cells was used to study the modulation of dhfr levels in response to release from amino acid deprivation. the addition of complete medium to cells grown for 48 hr in medium lacking isoleucine and glutamine caused the transfected cells to undergo a synchronous cycle of dna replication. when dhfr protein levels ass ... | 1988 | 3357483 |
| in vivo and in vitro effects of hydralazine on cellular growth, differentiation, and chromatin structure. | the effects of hydralazine (1-hydrazinophthalazine), an antihypertensive drug, on mammalian cell growth, viability, and differentiation were assessed using friend leukemia cells, chinese hamster ovary cells, human lymphocytes, and rat lymphocytes, testicular germ cells, and epididymal sperm. cultured cells in exponential phase growth were more susceptible to hydralazine cytotoxicity than stationary phase (g0) cells. growth inhibition was associated with a dose-related slowdown of cell progressio ... | 1988 | 3358268 |
| examination of vectors with two dominant, selectable genes for dna repair and mutation studies in mammalian cells. | a series of vectors with two dominant selectable genes was constructed for repair and mutation studies following transfer into mammalian cells. the recombinant genes (sv-gpt and hsvtk-neo) were placed in different relative orientations and positions in the vectors. these variables were shown to affect transformation frequency of cells by the vectors especially where one of the genes had a relatively weak expression, modelled by truncating the promoter of the hsvtk-neo gene. the use of two-gene v ... | 1988 | 3362156 |
| analysis of mutagenesis and sister-chromatid exchanges induced by 5-bromo-2'-deoxyuridine in somatic hybrids derived from syrian hamster melanoma cells and chinese hamster ovary cells. | somatic cell hybrids were derived from the fusion of chinese hamster ovary (cho) cells and syrian hamster melanoma cells (2e). these two cell lines had previously been shown to differ in their response to the induction of mutations and sister-chromatid exchanges (sces) by 5-bromo-2'-deoxyuridine (brdurd) (kaufman, 1987). the parental cells and a number of representative, independent hybrid clones were tested for their response to both the inc and rep mutagenesis protocols. inc mutagenesis involv ... | 1988 | 3362164 |
| the induction of numerical chromosome aberrations in human lymphocyte cultures and v79 chinese hamster cells by diethyl sulfate. | human lymphocyte cultures were treated with increasing concentrations of diethyl sulfate (des) at different times after stimulation with phytohemagglutinin (0, 24 and 45 h) and were scored for numerical chromosomal aberrations at different culture times (52, 72 and 96 h). a total of 3500 metaphases were analyzed. a statistically significant (p less than 0.01) increase in hypodiploid and hyperdiploid metaphases was found throughout the tested dose range (0.1-3 mm des); the increase in polyploid m ... | 1988 | 3367925 |