| extensive labeling with [3h]ethanolamine of a hydrophilic protein of animal cells. | murine t-lymphomas and thy-1- mutants were labeled overnight with [3h]ethanolamine to detect proteins which possess a glycophospholipid anchor. when labeled cells were treated with 10% trichloroacetic acid and then analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography, both thy-1 and a second intensely labeled protein (46 kda) were observed. the presence of the radiolabeled 46-kda protein in wild type and class e thy-1 negative cells (cells in which thy-1 is synt ... | 1988 | 3372524 |
| sulfated n-linked oligosaccharides in mammalian cells. i. complex-type chains with sialic acids and o-sulfate esters. | the structures of sulfated n-linked oligosaccharides have been reported for a few specific proteins. we recently demonstrated that such oligosaccharides occur in many different types of tissue culture cell lines (freeze, h. h., and varki, a. (1986) biochem. biophys. res. commun. 140, 967-973). here we report improved methods to metabolically label cell lines with 35so4 and to release sulfated n-linked oligosaccharides with peptide:n-glycosidase f as well as the partial structure of some of these ... | 1988 | 3379050 |
| intrinsic multidrug resistance phenotype of chinese hamster (rodent) cells in comparison to human cells. | in comparison to human cells, cell lines of chinese hamster and mouse origin exhibit between 10-50-fold resistance to a number of different drugs (viz. actinomycin d, daunomycin, chromomycin a3, colchicine, maytansine, mithramycin, puromycin, rhodamine 123, vinblastine and taxol). studies with a representative chinese hamster line (cho) and a single-step multidrug resistant (mdr) mutant of human (hela) cells show that: (i) in comparison to the sensitive human cells, both cell lines show a compar ... | 1988 | 3382391 |
| comparison of the cellular pharmacokinetics and toxicity of 2',2'-difluorodeoxycytidine and 1-beta-d-arabinofuranosylcytosine. | 2',2'-difluorodeoxycytidine (dfdc) is a new deoxycytidine analogue with good activity against human leukemic cell lines and murine solid tumors, while the activity of 1-beta-d-arabinofuranosylcytosine (ara-c) is established in experimental systems and for the treatment of human adult leukemia. this study compared the cellular metabolism and cytotoxic properties of dfdc and ara-c in chinese hamster ovary cells. in wild-type cells, dfdc was significantly more cytotoxic than ara-c after both 4- and ... | 1988 | 3383195 |
| statistical exploration of four major genotoxicity data bases: an overview. | this report puts into perspective a series of exploratory statistical analyses carried out on the major genotoxicity data bases. while large compilations of data, even though computerized, suffer from their own size and are quite intractable to scientific reflection and judgement, the multivariate data analysis methods used by us are specifically designed for reorganising the information in a rational way and highlighting the underlying regularities of the data. the analyses reported here refer ... | 1988 | 3383841 |
| protection of chinese hamster ovary cells from paraquat-mediated cytotoxicity by a low molecular weight mimic of superoxide dismutase (df-mn). | paraquat exerts a cytotoxic effect on chinese hamster ovary cells in culture via the superoxide radical (o2-). we have described a superoxide dismutase (sod) mimic based on manganese (df-mn) which consists of a one-to-one complex between desferrioxamine b (desferal) and mno2. it is a small molecular weight molecule, easy to prepare and possesses considerable stability. it is now shown to protect mammalian cells from paraquat toxicity. thus, 20 microm df-mn affords up to complete protection again ... | 1988 | 3384345 |
| tumour promotion related effects by the cyclodiene insecticide endosulfan studied in vitro and in vivo. | the cyclodiene insecticide endosulfan is structurally related to the tumour promoting pesticides chlordane and heptachlor. divergent conclusions have been reported regarding the carcinogenic activity of endosulfan. in this study we have investigated if endosulfan and four of its metabolites possess tumour promotion related effects. two in vitro test systems detecting inhibition of intercellular communication were used; the chinese hamster lung fibroblast (v79) metabolic cooperation assay and a s ... | 1988 | 3387377 |
| the semistability of centric chromatin bodies during long-term passage of multidrug resistant mouse-chinese hamster cell hybrids. | in a cell fusion experiment with multidrug resistant (mdr) mouse sewa tumor cells and sensitive chinese hamster cho cells, the resistant hybrid cells were completely without recognizable mouse chromosomes. instead, numerous chromatin bodies (cb) were found that contained copies of a high molecular weight p-glycoprotein gene (pgy1) associated with the mdr condition. the present paper reports on the cb under long-term selective and nonselective growth. the cb were of a stability intermediate betwe ... | 1988 | 3389736 |
| species-specific differences in the toxicity of puromycin towards cultured human and chinese hamster cells. | the toxicity of the protein synthesis inhibitor puromycin towards a number of human and chinese hamster cell lines has been examined. in comparison to cells of human origin, chinese hamster cells exhibited about 25-fold higher resistance towards puromycin. these differences appeared to be species related as all the cell lines from any one species showed similar sensitivity towards puromycin. the incorporation of [3h]leucine in the hamster cell lines was accordingly found to be more resistant to ... | 1988 | 3391265 |
| tpa enhancement of the recovery of methotrexate and n-phosphonacetyl l-aspartate resistant mouse 3t6 cell clones is associated with transient alterations of cell cycle progression. | the effects of methotrexate (mtx) and n-phosphonacetyl l-aspartate (pala) with and without 12-o-tetradecanoylphorbol-13-acetate (tpa) have been tested on the cell-cycle traverse of mouse 3t6 and chinese hamster v79 cell lines. mtx, whether administered with or without tpa, had very little effect on the cell cycle of the v79 chinese hamster cell line. however, low mtx concentrations produced a significant g1 accumulation in the mouse 3t6 cell line after 24 hr, and this was accentuated by tpa trea ... | 1988 | 3391707 |
| the uptake of pyrroline 5-carboxylate. group translocation mediating the transfer of reducing-oxidizing potential. | the cellular uptake of pyrroline 5-carboxylate (p5c) is of interest because this nutritionally responsive constituent of human plasma can mediate the transfer of oxidizing potential into cells and stimulate the production of phosphoribosyl pyrophosphate. using a cloned line of chinese hamster ovary cells, we found that the uptake of p5c was saturable, temperature-dependent, and sensitive to metabolic inhibitors. furthermore, this uptake of p5c exhibited unusual features. it was independent of so ... | 1988 | 3392037 |
| a mutant of chinese hamster ovary cells with a reduction in levels of dolichyl phosphate available for glycosylation. | f2a8, a glycosylation mutant of chinese hamster ovary cells, was isolated without prior enrichment or selective procedures by screening colonies for reduced [3h]mannose incorporation into macromolecules. f2a8 cells incubated with [3h]mannose synthesized 70% the amount of labeled gdp-mannose found in parental cells, and the same oligosaccharides attached to lipid and protein as did parental cells, but in reduced amounts. incorporation of radioactivity from labeled mannose into saccharide-lipids a ... | 1988 | 3392041 |
| cytopathic effect of heat-labile toxin of bordetella parapertussis on aortic smooth muscle cells from pigs or guinea pigs. | the in vitro effect of the heat-labile toxin (hlt) of bordetella parapertussis on hela, baby hamster kidney (bhk), chinese hamster ovary (cho), myeloma (pa-ns-1), human embryonic lung (hel-r66) cells, erythrocytes, adipocytes and lymphocytes from guinea pigs, mice or rats, or aortic smooth muscle cells from pigs or guinea pigs was examined. within 8, 6, 4, 2, and 2 hr after the exposure to 1, 3, 10, 30, and 100 mnds/ml of hlt, respectively, the cultured smooth muscle cells only showed a cytopath ... | 1988 | 3393100 |
| effect of endogenous glutathione, superoxide dismutases, catalase, and glutathione peroxidase on adriamycin tolerance of chinese hamster ovary cells. | based on the concept that activated oxygen species are causally involved in adriamycin toxicity, endogenous antioxidant defenses are expected to be important determinants of cellular adriamycin tolerance. we have tested this prediction by making use of an oxygen-resistant variant subline of chinese hamster ovary cells (chor), which is characterized by increased levels of glutathione, copper- and zinc-containing superoxide dismutase, manganese-containing superoxide dismutase, catalase, and glutat ... | 1988 | 3396001 |
| [karyotypes of cattle (bos taurus) and horses (equus caballus) on the basis of synaptonemal complexes]. | the cytogenetic study performed has shown that karyotyping of meiotic cells can be based on the synaptonemal complexes (sc) of spreading pachytene spermatocytes of bull and of horse. the horse sc karyotype has not been previously described. a comparison of the relative length of sc with metaphase chromosomes of bull and horse somatic cells has revealed the correspondence of the chromosome length in pachytene of meiosis and metaphase, which is in agreement with the data on house mouse and chinese ... | 1988 | 3396873 |
| the mink proopiomelanocortin gene: characterization of cdna and chromosomal localization. | a cdna library from the mink pituitary was screened using as probe a synthetic oligodeoxyribonucleotide, 5'-ttcatgacctccga-3', corresponding to the endorphin region of bovine proopiomelanocortin (pomc) cdna. as a result, several clones containing inserts complementary to pomc mrna were identified. the sequence of one of the fragments (585 bp, 65% of the total length of mrna) was determined. a high degree of homology (over 80%) among the primary structures of sequences from mink, man, and bovine ... | 1988 | 3397057 |
| the glycoprotein alpha-subunit is critical for secretion and stability of the human thyrotropin beta-subunit. | tsh is a member of a family of heterodimeric glycoprotein hormones which have a common alpha-subunit but differ in their hormone-specific beta-subunit. to study the posttranslational processing and assembly of human tsh, eukaryotic expression vectors were constructed that contained either the human tsh beta gene only or both the tsh beta and alpha-genes. these vectors were transfected into chinese hamster ovary cells and stable cell lines synthesizing tsh beta or tsh dimer were isolated. the kin ... | 1988 | 3398850 |
| the lec11 chinese hamster ovary mutant synthesizes n-linked carbohydrates containing sialylated, fucosylated lactosamine units. analysis by one- and two-dimensional 1h nmr spectroscopy. | glycoproteins synthesized by the chinese hamster ovary cell mutants lec11 and lec12 carry the lex determinant (gal beta 1,4(fuc alpha 1,3)glcnac), while those synthesized by lec11 cells also carry the sialyl-lex determinant (neuac alpha 2,3gal beta 1,4(fuc alpha 1,3)glcnac), and both mutants have been shown to possess a distinct alpha(1,3)-fucosyltransferase of the appropriate specificity to synthesize these determinants (campbell, c., and stanley, p. (1983) cell 35, 303-309; campbell, c., and s ... | 1988 | 3403533 |
| cryptic chemotactic activity of fibronectin for human monocytes resides in the 120-kda fibroblastic cell-binding fragment. | monocytes and lymphocytes form a second wave of infiltrating blood leukocytes in areas of tissue injury. the mechanisms for monocyte accumulation at these sites are not completely understood. recently, however, fragments from extracellular matrix proteins including collagen, elastin, and fibronectin have been shown to induce monocyte chemotaxis. in this report we demonstrate that chemotactic activity for human monocytes is expressed when a 120-kda fragment containing the rgds cell-binding peptid ... | 1988 | 3403561 |
| analysis of signals controlling expression of the chinese hamster ovary aprt gene. | the 5' end of the chinese hamster ovary aprt gene was sequenced and transcription start sites were determined by both s1 nuclease protection and primer extension assays. deletion mutants covering the same area were constructed, and adenine phosphoribosyltransferase (aprt) or chloramphenicol acetyltransferase (cat) activity was measured by transient-expression assays. the aprt gene uses a single cluster of transcription start sites and lacks consensus sequences such as tata and ccaat, which are g ... | 1988 | 3405212 |
| biological activities of phthalocyanines--ix. photosensitization of v-79 chinese hamster cells and emt-6 mouse mammary tumor by selectively sulfonated zinc phthalocyanines. | | 1988 | 3406131 |
| cellular effects of t-2 mycotoxin on two different cell lines. | the effects of t-2 toxin on protein synthesis, respiratory chain activity of the mitochondria, cell lysis and toxin-cell binding were compared in the toxin-sensitive bovine kidney cell line (mdbk) and in the toxin-resistant chinese hamster ovary cell line (cho). protein synthesis and mitochondrial activity were 10-fold less sensitive in cho cells as compared to mdbk (50% inhibition = 10-15 ng/ml vs. 1-1.5 ng/ml, respectively). lytic activity, as determined by release of 51cr from cells incubated ... | 1988 | 3408740 |
| transformation of c3h/10t1/2 mouse embryo cells to focus formation and anchorage independence by insoluble lead chromate but not soluble calcium chromate: relationship to mutagenesis and internalization of lead chromate particles. | the genotoxicity of soluble and insoluble hexavalent chromium compounds was studied in mammalian cell assays which detect base substitution, deletion, addition, and frameshift mutations [6-thioguanine resistance in chinese hamster ovary cells], primarily base substitution mutations [ouabain resistance in chinese hamster ovary and c3h/10t1/2 cl 8 mouse embryo fibroblasts (10t1/2)] and morphological transformation [focus formation] in 10t1/2 cells. soluble hexavalent cacro4, administered in either ... | 1988 | 3409252 |
| the contribution of o6-methylguanine and methylphosphotriesters to the cytotoxicity of alkylating agents in mammalian cells. | a modified escherichia coli ada+ gene which encodes methyltransferase active on o6-methylguanine, but not methylphosphotriester residues in dna has been introduced by transfection into chinese hamster ovary cells. expression of the altered ada protein in these cells conferred resistance to methylating agents. however, in two independently derived cell lines, the relation between enzyme activity and the degree of protection was not quantitative. the molecular nature of the ada protein fragment pr ... | 1988 | 3409462 |
| some studies on the dna-repair-eliciting and genotoxic activity of cell-free extracts of lactobacillus bifidus. | cell-free extracts of lactobacillus bifidus have been reported as possessing dna-repair-eliciting properties in uv-irradiated human cells, and suggestions have been made that these extracts could be used to protect human skin cells from dna-damaging effects induced by natural uv light. in view of the importance of these findings, and because extracts of other bifidobacteriae had previously been shown to possess genotoxic activity in bacterial systems, it seemed appropriate to perform some experi ... | 1988 | 3412372 |
| sister-chromatid exchanges induced by triethylenemelamine: in vivo and in vivo/in vitro studies in mouse and chinese hamster bone marrow and spleen cells. | this study was designed to obtain sister-chromatid exchange (sce) frequencies in bone marrow and spleen cells of mice and chinese hamsters under in vivo and in vivo/in vitro systems following treatment of animals with varying doses (15-405 micrograms/kg) of triethylenemelamine (tem). a dose-related sce response was found in both species, tissues, and systems analyzed following tem treatment. in vivo, similar responses were noted for both tissues in both species. however, in vivo/in vitro, the re ... | 1988 | 3412373 |
| human repair gene restores normal pattern of preferential dna repair in repair defective cho cells. | the pattern of preferential dna repair of uv-induced pyrimidine dimers was studied in repair-deficient chinese hamster ovary (cho) cells transfected with the human excision repair gene, ercc-1. repair efficiency was measured in the active dihydrofolate reductase (dhfr) gene and in its flanking, non-transcribed sequences in three cell lines: wild type cho cells, a uv-sensitive excision deficient cho mutant, and the transfected line of the mutant carrying the expressed ercc-1 gene. the cho cells t ... | 1988 | 3412890 |
| evaluation of the l5178y mouse lymphoma cell mutagenesis assay: interlaboratory reproducibility and assessment. | the l5178y mouse lymphoma cell mutagenesis assay is used to detect the mutagenic activity of chemicals in a mammalian cell system. to evaluate this assay we compared the results of assays performed independently on 63 chemicals by laboratories at sri international and litton bionetics, inc. the two laboratories used similar protocols. the solvent and positive control mutant frequencies and cloning efficiencies obtained by the two laboratories were similar, which justified the use of the same qua ... | 1988 | 3416840 |
| computer-assisted analysis of interlaboratory ames test variability. | the interlaboratory ames test variability of the salmonella/microsome assay was studied by comparing 12 sets of results generated in the frame of the international program for the evaluation of short-term tests for carcinogens (ipesttc). the strategy for the simultaneous analysis of test performance similarities over the whole range of chemicals involved the use of multivariate data analysis methods. the various sets of ames test data were contrasted both against each other and against a selecti ... | 1988 | 3418743 |
| pretreatment with oxygen species increases the resistance of mammalian cells to hydrogen peroxide and gamma-rays. | pretreatment of chinese hamster ovary (cho) or h4 (rat hepatoma) cells with low non-toxic doses of h2o2 or xanthine-xanthine oxidase renders the cells more resistant to the toxic effect of h2o2 and gamma-rays. this increased resistance is observed both in exponentially growing and in plateau-phase cells. cells pretreated with xanthine-xanthine oxidase are less mutated than control cultures when challenged with ionizing radiation. the number of dna single-strand breaks (measured by nucleoid sedim ... | 1988 | 3419450 |
| cytoskeletal alterations as a parameter for assessment of toxicity. | 1. some environmental substances, drugs and pollutants affect the growth of cultured cells, and produce cytoskeletal alterations. 2. these have been used as parameters for toxicity assessment of cholera toxin and pertussis toxin in chinese hamster ovary cells. 3. cholera toxin stabilized microtubules and had no effect on microfilaments and intermediate filaments. 4. pertussis toxin affected microfilaments but appeared to have no effect on microtubules and intermediate filaments. | 1988 | 3420947 |
| production of human thyroid-stimulating hormone in chinese hamster ovary cells. | human thyroid-stimulating hormone (htsh) has been produced in chinese hamster ovary (cho) cells co-transformed with two plasmids: one carrying the alpha subunit cdna with mouse dihydrofolate reductase gene and the other carrying htsh beta subunit cdna. each cdna was driven to expression under the control of sv40 early promoter. htsh and its alpha subunit were secreted into culture media, and their secretion increased with exposure of the cells to increasing concentrations of methotrexate. gel fi ... | 1987 | 3426611 |
| regulation of squalene epoxidase activity and comparison of catalytic properties of rat liver and chinese hamster ovary cell-derived enzymes. | squalene epoxidase activity has been studied in cell-free preparations of chinese hamster ovary (cho) cells and rat liver. in contrast to rat liver microsomal squalene epoxidase, the enzyme of cho cells is only slightly activated by the autologous cytosolic fraction, whereas phosphatidylglycerol or rat liver cytosolic preparations are potent stimulators of this enzyme. triton x-100, a known stimulator of the hepatic squalene epoxidase, has no activating effect on the enzyme of cho cells. the squ ... | 1987 | 3430067 |
| restriction of human adenovirus replication in chinese hamster cell lines and their hybrids with human cells. | we have found that the replication of human adenovirus (ad2) is restricted in multiple chinese hamster cell lines including cho and v79. the major site of restriction involves differential accumulation of late viral proteins as demonstrated by immunofluorescence assay and polyacrylamide gel electrophoresis with and without prior immunoprecipitation. synthesis of fiber and penton base are markedly reduced, whereas others, such as the 100k polypeptide, are synthesized efficiently. this pattern of ... | 1987 | 3433922 |
| [mutagenic action of cadmium chloride in mammals]. | the mutagenic effect of cadmium chloride on somatic cells of f1 hybrid mice cba x c57b1/6j in vivo and on an established line of cho-atz-2 chinese hamster cells in vitro has been studied. the induction of micronuclei has been demonstrated in mouse marrow cells as well as induction of point mutations at loci controlling the synthesis of hypoxanthine-phosphoribosyltransferase, thymidine kinase, adenine phosphoribosyltransferase and the resistance of na+/k+ atpase to ouabain in the cell line cho-at ... | 1987 | 3435731 |
| mitochondrial matrix localization of a protein altered in mutants resistant to the microtubule inhibitor podophyllotoxin. | specific antibodies to a protein designated p1 (mr approximately equal to 63,000), which is specifically altered in mutants resistant to the microtubule inhibitor podophyllotoxin, bind to mitochondria in cells of various vertebrate and invertebrate species (eur. j. cell biol. 44, 278-285 (1987); can. j. biochem. cell biol. 63, 489-502 (1985)). to investigate the relationship of this protein to mitochondria, rat liver mitochondria have been purified and immunoblot analysis with these provide evid ... | 1987 | 3443110 |
| evaluation of matrix effects in ion microscopic analysis of freeze-fractured, freeze-dried cultured cells. | sims matrix effects (mass interferences, sputter yield variations and practical ion yield variations) were evaluated in freeze-fractured, freeze-dried cultured cells at the approximately 0.5 micron spatial resolution of the cameca ims-3f ion microscope. cell lines studied include normal rat kidney (nrk), 3t3 mouse fibroblast, l6 rat myoblast, chinese hamster ovary (cho) and rat kangaroo kidney (ptk2) cells. high mass resolution studies indicated that the secondary ion signals of h-, c-, o-, na+, ... | 1987 | 3443979 |
| regional assignment of human alcohol dehydrogenase (adh) gene to 4pter----4q21. | the hybrid clone fd1 constructed by fusion of chinese hamster cell line wg3-h with human lymphocyte was irradiated with x-ray. fourteen survival clones were isolated and 3 of them, f5b, f52b, f61a were analyzed in detail by cytogenetic and biochemical methods. the results of chromosome g-banding followed by giemsa-11 differential staining show that there exists a deleted human chromosome 4 in all of the three hybrids. this deletion of human chromosome 4 in f61a is 4pter----4q21. the results of i ... | 1987 | 3445134 |
| multiple-endpoint mutagenesis with chinese hamster ovary (cho) cells: evaluation with eight carcinogenic and non-carcinogenic compounds. | previously, we have shown that chinese hamster ovary (cho) cells are useful for quantifying chemical-induced gene mutations. we have defined the conditions of a multiplex cho system which permits determination of mutagen-induced chromosome aberration, and sister chromatid exchange (sce) in addition to cytotoxicity and gene mutation in the same treated culture. this allows us to extend the spectrum of quantitative mutagenesis to include clastogenic endpoints. in the present study, we used four ca ... | 1987 | 3449758 |
| structure and expression of the chinese hamster thymidine kinase gene. | my colleagues and i have cloned a nearly full-length chinese hamster thymidine kinase (tk) cdna in a lambda gt10 vector and characterized this cdna by nucleotide sequencing. the hamster tk protein is encoded in this cdna by a 702-base-pair open reading frame which specifies a 25,625-dalton protein closely homologous to the previously described human and chicken tk proteins. using cdna nucleotide sequence data in conjunction with sequence data derived from selected subclones of the hamster tk gen ... | 1986 | 3453109 |
| assignment of the gene for carboxypeptidase a to human chromosome 7q22----qter and to mouse chromosome 6. | a rat cdna probe for preprocarboxypeptidase a was used to follow the segregation of the human gene for carboxypeptidase a (cpa) in 49 human x mouse somatic cell hybrids using southern filter hybridization techniques. cpa was assigned to human chromosome 7q22----qter. similarly, the probe was used to follow the segregation of the mouse gene for carboxypeptidase a (cpa) in 19 mouse x chinese hamster somatic cell hybrids. cpa was assigned to mouse chromosome 6. the gene for carboxypeptidase a forms ... | 1986 | 3455919 |
| common proviral integration region on mouse chromosome 7 in lymphomas and myelogenous leukemias induced by friend murine leukemia virus. | friend murine leukemia virus (f-mulv) induces a variety of hematopoietic neoplasms 2 to 12 months after inoculation into newborn mice. these neoplasms are clonal or oligoclonal and contain a small number of f-mulv insertions in high-molecular-weight dna. to investigate whether different tumors have proviral insertions in the same region, a provirus-cellular dna junction fragment from an f-mulv-induced myelogenous leukemia was cloned in lambda gtwes, and a portion of the flanking cellular dna seq ... | 1986 | 3456057 |
| comparative analysis of natural killer cell and macrophage recognition of concanavalin a-resistant chinese hamster ovary cells: role of membrane oligosaccharides. | as was previously shown, a mutation rendering chinese hamster ovary (cho) cells concanavalin a (con a) resistant (con ar) resulted in enhanced binding and susceptibility to lysis by natural killer (nk) cells. in the present study altered cell surface carbohydrate expression on the con ar cr-7 cell line was demonstrated. this could be detected by flow cytometry with the use of fluorescein isothiocyanate-conjugated lectins con a, wheat-germ agglutinin, and peanut agglutinin, and by a radiolabeled ... | 1986 | 3456064 |
| assignment of human 3-hydroxy-3-methylglutaryl coenzyme a reductase gene to q13----q23 region of chromosome 5. | we have used hamster cdna probes for 3-hydroxy-3-methylglutaryl coenzyme a (hmg coa) reductase (hmgcr) to determine the chromosomal location of the human gene for hmg coa reductase. southern blot analysis of genomic dna from 16 independent mouse-human somatic cell hybrids showed that the human gene for hmg coa reductase resides on chromosome 5. analysis of chinese hamster-human somatic cell hybrids selectively retaining human 5 or a portion of it showed that the gene locus for hmg coa reductase ... | 1986 | 3456176 |
| functional hemizygosity for the mdh2 locus in chinese hamster ovary cells. | isolation of electrophoretic mobility shift mutants for a large number of enzyme loci in cho cells has allowed the identification of many genes which are functionally hemizygous. to gain further insight into the nature of hemizygosity in cho cells and the mechanisms by which it has arisen, we are attempting to determine whether hemizygous gene loci are clustered in a few localized chromosomal regions in cho or are more generally distributed throughout the genome. isozyme analysis of a series of ... | 1986 | 3457474 |
| genetic counterselective procedure to isolate interspecific cell hybrids containing single human chromosomes: construction of cell hybrids and recombinant dna libraries specific for human chromosomes 3 and 4. | counterselection against genes on human chromosome 5 was applied to interspecific human-chinese hamster cell hybrids which retained this and one additional human chromosome in order to generate cell hybrids retaining single, nonselected human chromosomes. using this procedure, stable cell hybrids which retain human chromosome 3 exclusively or human chromosome 4 exclusively were isolated. complete recombinant genomic dna libraries were prepared from each hybrid using the lambda cloning vector emb ... | 1986 | 3457476 |
| identification of 200,000-dalton human cell surface protein encoded by gene mapped to long arm of chromosome 11. | cell surface proteins and glycoproteins of human and chinese hamster cells and their hybrid cell clones were analyzed by two-dimensional gel electrophoresis. the j1 clone of human-chinese hamster hybrid cells contained chromosome 11 as its only human chromosome. the j1 cells expressed a glycoprotein of 200,000 daltons which was shared by human fibroblasts but not by the parental chinese hamster ovary cells. the 200,000-dalton protein was identified as a cell surface protein by the method of lact ... | 1986 | 3457478 |
| survival of uv-irradiated mammalian cells correlates with efficient dna repair in an essential gene. | the survival of uv-irradiated mammalian cells is not necessarily correlated with their overall capacity to carry out dna repair. human cells typically remove 80% of the pyrimidine dimers produced by a uv dose of 5 j/m2 within 24 hr. in contrast, a chinese hamster ovary (cho) cell line survives uv irradiation equally well while removing only 15% of the dimers. using a newly developed technique to measure dimer frequencies in single-copy specific sequences, we find that the cho cells remove 70% of ... | 1986 | 3459159 |
| isolation of human mdr dna sequences amplified in multidrug-resistant kb carcinoma cells. | the ability of tumor cells to develop simultaneous resistance to structurally different cytotoxic drugs constitutes a major problem in cancer chemotherapy. it was previously demonstrated that multidrug-resistant chinese hamster cell lines contain an amplified, transcriptionally active dna sequence designated mdr. this report presents evidence that multidrug-resistant sublines of human kb carcinoma cells, selected for resistance to either colchicine, vinblastine, or adriamycin (doxorubicin), disp ... | 1986 | 3459187 |
| ribosomal protein gene sequences map to human chromosomes 5, 8, and 17. | dna sequences complementary to six mammalian ribosomal protein (r-protein) cdnas are assigned to human chromosomal linkage groups in human-chinese hamster hybrid cell clones. ten r-protein dna fragments map to chromosomes 5, 8 and 17, indicating that these important, housekeeping genes are distributed to multiple sites in the human genome. each of the chromosome assignments, determined initially by surveying chinese hamster-human hybrid cell clones with complex karyotypes using chinese hamster a ... | 1986 | 3459254 |
| transforming growth factor beta gene maps to human chromosome 19 long arm and to mouse chromosome 7. | transforming growth factors (tgf) are defined as biologically active polypeptides which reversibly confer the transformed phenotype onto untransformed cultured cells. they have been subdivided into two classes: type alpha and type beta tgfs. tgf-beta acts synergistically with tgf-alpha in inducing phenotypic transformation. tgf-beta can also act as a negative autocrine growth factor. a human 1050-bp ecori cdna fragment was used to map the human locus for tgf-beta by southern blotting of dna prep ... | 1986 | 3459257 |
| differential tumorigenicity of growth factor-dependent versus -independent ccl39 lung fibroblast lines in nude mice. | several cell lines derived from ccl39 chinese hamster fibroblasts were characterized so that comparison could be made of their tumorigenic potential and their ability to proliferate in vitro in response to growth factor stimulation. tumor formation was assessed by implanting single-cell suspensions into the flanks (sc), peritoneal cavity (ip), or tail vein (iv) of balb/c athymic nude mice, whose ages ranged from 8-10 days (neonatal), to 5-7 weeks (adult), to more than 5 months (old). serum, insu ... | 1986 | 3459908 |
| induction of chromosome aberrations by fusarium t-2 toxin in cultured human peripheral blood lymphocytes and chinese hamster fibroblasts. | t-2 toxin is an important representative of trichothecenes produced by various species of imperfect fungi, mainly fusarium genus. it is a naturally occurring toxin that can cause severe diseases in human and animals. no definite data demonstrating the carcinogenic potential of t-2 toxin had been reported up to now. we demonstrated that t-2 toxin reproducibly induced chromosomal structural aberrations both in cultured human peripheral blood lymphocytes as well as in v79 chinese hamster fibroblast ... | 1986 | 3462193 |
| induction of differentiation in human myeloid leukemia cells with cytosine arabinoside. | normalization of granulocyte counts was obtained with low-dose cytosine arabinoside (ara-c) in a patient with acute myelogenous leukemia (aml, fab-m2) who had relapsed on maintenance therapy containing conventional doses of ara-c and was clinically resistant to high-dose ara-c treatment. the patient's leukemic cells exhibited an abnormal karyotype (45, x-y, t[8q; 21q]). to determine whether the response to low-dose ara-c was a result of induced leukemic cell differentiation, the mature periphera ... | 1986 | 3462437 |
| 2,4-dichlorobenzyl thiocyanate, an antimitotic agent that alters microtubule morphology. | a compound of simple structure, 2,4-dichlorobenzyl thiocyanate (dcbt), is an antimitotic agent with a number of unusual properties. the drug causes an extreme reorganization of microtubules in cells in culture. most normal microtubules disappear, and remaining tubulin-containing structures appear to be bundled or aggregated. dcbt irreversibly inhibits in vitro polymerization of purified tubulin, but only after a prolonged preincubation of the protein with the drug. binding of radiolabeled dcbt t ... | 1986 | 3462730 |
| chromosomal assignment of the human erythropoietin gene and its dna polymorphism. | erythropoietin (epo), a glycoprotein hormone, is the major physiological regulator of erythrocyte production in mammals. a cdna clone containing the entire human epo-coding region was used for 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 epo gene and human chromosome 7. further localization to the region q11-q22 was accomplished by in situ hybridizati ... | 1986 | 3462737 |
| cloning and sequence analysis of cdna for human argininosuccinate lyase. | using antibodies specific for argininosuccinate lyase (ec 4.3.2.1), we isolated two cdna clones by screening a human liver cdna library constructed in the lambda gt11 expression vector. the identity of these isolates was confirmed by in vitro translation of plasmid-selected mrna. one of these isolates was used to rescreen the cdna library and a 1565-base-pair (bp) clone was identified. the entire nucleotide sequence of this clone was determined. an open reading frame was identified which encoded ... | 1986 | 3463959 |
| mitochondrial protein synthesis in interspecific somatic cell hybrids. | the fusion of an oligomycin (oli)-resistant mutant of mouse lm(tk-) cells to a chloramphenicol (cap)-resistant mutant of ak412 chinese hamster cells resulted in a series of interspecific somatic cell hybrids. hybrids selected in hat medium retained only mouse mitochondrial genomes while hybrids selected in hat plus cap and oli retained both hamster and mouse mitochondrial genomes in approximately equal amounts. nuclear-coded mitochondrial proteins from both parental species were incorporated int ... | 1986 | 3464102 |
| chromosomal localization of human gene for histidyl-trna synthetase: clustering of genes encoding aminoacyl-trna synthetases on human chromosome 5. | the gene encoding histidyl-trna synthetase was localized to human chromosome 5 using human-chinese hamster ovary cell hybrids. seven of the functionally related genes encoding the 20 different aminoacyl-trna synthetases have not been mapped in humans and four are located on a single chromosome, number 5, which represents less than 7% of the total genome. thus, there appears to be significant clustering of this group of genes which may reflect their evolutionary relatedness or common factors invo ... | 1986 | 3464104 |
| threonyl-trna synthetase gene maps close to leucyl-trna synthetase gene on human chromosome 5. | the structural gene for threonyl-trna synthetase was mapped to human chromosome 5 by an analysis of the isoelectric focusing patterns of this enzyme from human x chinese hamster interspecific somatic cell hybrids. the threonyl-trna synthetase gene is the fourth of seven aminoacyl-trna synthetase genes mapped in humans to be assigned to this chromosome. regional mapping studies showed that the threonyl-trna synthetase gene is on the short arm of chromosome 5, p13-cen, and is close to, but separab ... | 1986 | 3464105 |
| characterization of human folylpolyglutamate synthetase expressed in chinese hamster ovary cells. | chinese hamster aux b1 cells lack the enzyme folylpolyglutamate synthetase (fpgs) responsible for adding polyglutamates to folic acid. the human gene for fpgs was introduced into aux b1 cells by cotransfection with human genomic dna and either psv2neo or psv2gpt plasmid dna. cells were coselected for fpgs expression by growth in the absence of glycine, adenosine, and thymidine, and for drug resistance by growth in geneticin or mycophenolic acid. the presence of human enzyme in transfected cells ... | 1986 | 3466358 |
| the terminal deoxynucleotidyltransferase gene is located on human chromosome 10 (10q23----q24) and on mouse chromosome 19. | terminal deoxynucleotidyltransferase (tdt) is a dna polymerase expressed in immature lymphocytes of the thymus and bone marrow, as well as certain leukemic cells. chromosomal assignment of the gene coding for human tdt was accomplished by in situ hybridization of a 3h-labeled cdna probe to human chromosome preparations and by southern blot analysis of somatic cell hybrid dnas. the human tdt gene was mapped to the region q23----q24 of chromosome 10. breaks at this site have been reported in diffe ... | 1986 | 3467897 |
| [homology of g-banded mammalian chromosomes]. | linkage relationships of homologous loci and high resolution g-banding patterns of man, mouse, rat, chinese hamster, rabbit, cat, mink, pig, ox and sheep were used for identification of 11 evolutionary conservative autosomal regions. the distributions and inversions of these regions in the ancestor genomes of some phylums have been shown. for example, the regions homologous to human ip region were detected in cat, mink and rabbit genomes. in the genomes of rodents studied the intraregion inversi ... | 1987 | 3469125 |
| replication of proto-oncogenes early during the s phase in mammalian cell lines. | members of several classes of proto-oncogenes replicate during the first third of s-phase in two human (k562 erythroleukemia and hela), one chinese hamster (cho) and eight mouse cell lines. these cell lines exhibit a variety of specialized functions characteristic of pre-b and b cells, t cells and erythroid cells. the proto-oncogenes studied include fos, myc, myb, abl, fes, fms, mos, raf, rel, sis, ha-ras, ki-ras, and n-ras. in k562 cells, amplified and rearranged c-abl genes show a pattern of t ... | 1987 | 3469620 |
| optional exon in the 5'-untranslated region of 3-hydroxy-3-methylglutaryl coenzyme a synthase gene: conserved sequence and splicing pattern in humans and hamsters. | 3-hydroxy-3-methylglutaryl coenzyme a synthase (hydroxymethylglutaryl-coa synthase, ec 4.1.3.5) is a negatively regulated enzyme in the synthetic pathway for cholesterol, isopentenyl trna, and other isoprenoids. the 5'-untranslated region of the mrna for chinese hamster hydroxymethylglutaryl-coa synthase contains an optional exon of 59 nucleotides located 10 nucleotides upstream of the translation start site. about 50% of the mrnas contain this exon, and the other 50% lack it owing to differenti ... | 1987 | 3470763 |
| resistance to toxic effects of 5-hydroxymethyl-2'-deoxyuridine in mammalian cells. | a spontaneously arising clone, stably resistant to the toxic effects of the thymidine analog, 5-hydroxymethyl-2'-deoxyuridine (hmdu), was isolated from unmutagenized v79.5 chinese hamster fibroblast cells by a single-step selection procedure. the hmdur cells were selected in the continuous presence of 30 microm hmdu, a concentration which reduces the plating efficiency of wild-type cells to less than 1% after a 24-h exposure. a line of human hela cells were found to be intrinsically resistant to ... | 1987 | 3470950 |
| chromosomal location of human genes encoding major heat-shock protein hsp70. | the hsp70 family of heat-shock proteins constitutes the major proteins synthesized in response to elevated temperatures and other forms of stress. in eukaryotes members of the hsp70 family also include a protein similar if not identical to bovine brain uncoating atpase and glucose-regulated proteins. an intriguing relation has been established between expression of heat-shock proteins and transformation in mammalian cells. elevated levels of hsp70 are found in some transformed cell lines, and vi ... | 1987 | 3470951 |
| gene assignments and syntenic groups in the sacred baboon (papio hamadryas). | eighteen genes were assigned to chromosomes in the sacred baboon, papio hamadryas, by their concordant segregation with the chromosomes in a set of baboon x chinese hamster somatic cell hybrids. acy1 was assigned to p. hamadryas chromosome 2 (pha 2); sod1 and mdh2 to pha 3; me1 and sod2 to pha 4; np, mpi, pkm2, and hexa to pha 7; pp to pha 9; ada and itpa to pha 10; ldhb and tpi1 to pha 11; mdh1 to pha 13; esd to pha 17; and gpi and pepd to pha 20. regional assignments were possible for acy1 (ph ... | 1987 | 3471391 |
| random cloning of genes from mouse chromosome 17. | we describe a method for isolating cosmid clones randomly from mouse chromosome 17. a cosmid library was constructed from the mouse-chinese hamster cell line r4 4-1 that contains a limited amount of mouse dna (chromosomes 17 and 18 and some other unidentified material) on a chinese hamster background. the library was screened with the murine repetitive sequence probe pmba14, which selectively hybridizes with mouse dna. the mouse-derived cosmid clones thus identified were individually hybridized ... | 1987 | 3472212 |
| the progesterone receptor gene maps to human chromosome band 11q13, the site of the mammary oncogene int-2. | progesterone is involved in the development and progression of breast cancers, and progesterone receptors (pr) are important markers of hormone dependence and disease prognosis. we have used a human pr cdna probe, genomic dna blotting of a series of chinese hamster-human cell hybrids, and in situ hybridization to map the human pr gene to chromosome 11, band q13. this band also contains the human homolog of the mouse mammary tumor virus integration site, int-2, which surrounds a protooncogene tho ... | 1987 | 3472240 |
| molecular analysis and chromosomal mapping of amplified genes isolated from a transformed mouse 3t3 cell line. | we are exploring the origin and function of amplified dna sequences associated with double minutes (dms) in a spontaneously transformed derivative of mouse 3t3 cells. toward that goal, we have constructed a cdna library using rna from these cells and have isolated cdna clones representing sequences that are amplified and overexpressed in these 3t3-dm cells. from results of northern- and southern-blot analyses, we conclude that these cdnas represent two distinct genes, which we have designated md ... | 1987 | 3474784 |
| transfection of normal human and chinese hamster dna corrects diepoxybutane-induced chromosomal hypersensitivity of fanconi anemia fibroblasts. | cultured cells from individuals affected with fanconi anemia (fa) exhibit spontaneous chromosome breakage and hypersensitivity to the cell killing and clastogenic effects of the difunctional alkylating agent diepoxybutane (deb). we report here the correction of both of these deb-hypersensitivity phenotypes of fa cells achieved by cotransfection of normal placental or chinese hamster lung cell dna and the plasmid psv2-neo-svgpt. transfectants were selected for clonogenic survival after treatment ... | 1987 | 3475705 |
| expression of the genes encoding bovine lh in a line of chinese hamster ovary cells. | synthesis of biologically active lh is complex, due in part to its heterodimeric subunit structure and to the numerous post-translation modifications of each subunit. through the use of mammalian expression vectors we have been able to introduce the bovine alpha subunit and lh-beta genes into a chinese hamster ovary cell line deficient in dihydrofolate reductase. the bovine genes are actively expressed and the chinese hamster ovary cells secrete biologically active lh. the expression vector cont ... | 1987 | 3476749 |
| effects of preventing o-glycosylation on the secretion of human chorionic gonadotropin in chinese hamster ovary cells. | human chorionic gonadotropin (hcg) is a member of a family of heterodimeric glycoprotein hormones that have a common alpha subunit but differ in their hormone-specific beta subunits. the beta subunit of hcg (hcg beta) is unique among the beta subunits in that it contains four mucin-like o-linked oligosaccharides attached to a carboxyl-terminal extension. to study the effects of o-glycosylation on the secretion and assembly of hcg, expression vectors containing either the hcg beta gene alone or t ... | 1987 | 3476951 |
| genetic evidence for nucleotide excision repair of o6-alkylguanine in mammalian cells. | human cells that lack o6-alkylguanine dna alkyltransferase (at) activity can remove o6-butylguanine (o6-nbug) produced in cellular dna by exposure to n-n-butyl-n-nitrosourea as determined by radioimmunoassay of enzyme digests of dna. fibroblasts from xeroderma pigmentosum (xp) complementation groups a and g that show less than 5% unscheduled dna synthesis following exposure to uvc failed to remove o6-nbug. hence it appears that o6-alkylguanine is repaired in cells that lack at by a process that ... | 1987 | 3477561 |
| dna synthesis in irradiated mammalian cells. | one of the first responses observed in s phase mammalian cells that have suffered dna damage is the inhibition of initiation of dna replicons. in cells exposed to ionizing radiation, a single-strand break appears to be the stimulus for this effect, whereby the initiation of many adjacent replicons (a replicon cluster) is blocked by a single-strand break in any one of them. in cells exposed to ultraviolet light (u.v.), replicon initiation is blocked at fluences that induce about one pyrimidine di ... | 1987 | 3477563 |
| recent progress with the dna repair mutants of chinese hamster ovary cells. | repair-deficient mutants of chinese hamster ovary (cho) cells are being used to identify human genes that correct the repair defects and to study mechanisms of dna repair and mutagenesis. five independent tertiary dna transformants were obtained from the em9 mutant, which is noted for its very high sister-chromatid exchange frequencies. in these clones a human dna sequence was identified that correlated with the resistance of the cells to chlorodeoxyuridine (cldurd). after ecori digestion, south ... | 1987 | 3477565 |
| specific induction of acnu-resistance in v79 chinese hamster cells and c6 rat glioma cells. | the antitumor compound acnu (1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitroso ure a hydrochloride) is widely used for treatment of malignant brain tumors. the authors have investigated the mechanism of acquisition of acnu resistance at the cellular level by isolating acnu-resistant mutants from v79 chinese hamster cells and c6 rat glioma cells after treatment of the cells with acnu or other alkylating agents. in v79 chinese hamster cells, acnu at 1 to 4 micrograms/ml caused d ... | 1987 | 3477613 |
| polyadenylation of chinese hamster dihydrofolate reductase genomic genes and minigenes after gene transfer. | the major alternative polyadenylation sites in the chinese hamster dihydrofolate reductase (dhfr) gene have been identified by dna sequencing and rnase protection experiments. comparison of the 3' gene sequence and polyadenylation sites with those of the mouse reveals that, despite an overall sequence homology, the major sites are different in the two species. a series of minigenes was constructed containing the dhfr promoter and the first intron but lacking the four large introns of the genomic ... | 1987 | 3477873 |
| correction of excision repair in xeroderma pigmentosum by hamster chromosome fragments involves both classes of pyrimidine dimers. | the ultraviolet light-sensitive phenotype of xeroderma pigmentosum (xp) has been corrected by the incorporation into xp cells of small chromosome fragments from chinese hamster ovary cells. like normal human and hamster cells, these xp-hamster hybrids are able to excise both of the photoproducts produced by ultraviolet light: cyclobutane pyrimidine dimers and the minor photoproduct, (6-4) pyrimidine-pyrimidone dimers. this excision capacity contrasts with that of an xp revertant, of the same cel ... | 1987 | 3478816 |
| assignment of the lactotransferrin gene to human chromosome 3 and to mouse chromosome 9. | lactotransferrin (ltf), a member of the transferrin family of genes, is the major iron-binding protein in milk and body secretions. the amino acid sequence of ltf consists of two homologous domains homologous to proteins in the transferrin family. recent isolation of cdna encoding mouse ltf has expedited the mapping of both mouse and human ltf genes. southern blot analysis of dna from mouse-chinese hamster and human-mouse somatic cell hybrids maps the ltf gene to mouse chromosome 9 and to human ... | 1987 | 3478818 |
| type 1 transforming growth factor beta: amplified expression and secretion of mature and precursor polypeptides in chinese hamster ovary cells. | recombinant type 1 transforming growth factor beta (tgf-beta) was expressed to high levels in cho cells by using dihydrofolate reductase (dhfr) gene amplification. the expression plasmid was derived from the psv2 vectors and contained, in tandem, the simian tgf-beta and mouse dhfr cdnas. transcription of both cdnas was controlled by the simian virus 40 early promoter. stepwise selection of transfected cho cells in increasing concentrations of methotrexate yielded cell lines that expressed amplif ... | 1987 | 3479680 |
| effect of radiomodifying agents on the ratios of x-ray-induced lesions in cellular dna: use in lethal lesion determination. | the effect of three radiomodifying agents, cysteamine, hyperthermia, and hypoxia, on the induction of the major classes of x-ray-induced dna lesions, was studied using mouse l cells and chinese hamster v79 cells. the use of filter elution techniques allowed most of these studies to be conducted at x-ray doses within the survival-curve range. cysteamine was found to protect against dna single-strand breakage (ssb), dna base damage, and dna-protein crosslinkage. hyperthermia had no effect on the l ... | 1986 | 3485604 |
| the role of phlebotomus alexandri sinton, 1928 in the transmission of kala-azar. | since 1968, kala-azar has been occurring sporadically in meiyaogou, turfan county, xinjiang-uygur autonomous region, where four species of sandflies are known to exist. the present study of sandflies collected in this area from may to august 1983 shows that phlebotomus alexandri is the only anthropophilic and predominant species, accounting for 81.1% (7716/8843) of the sandfly population. after having been fed on cotton rats or hamsters infected with leishmania donovani, 93.9% (230/245) of p. al ... | 1986 | 3488133 |
| secretion of glycosylated human interleukin-2 by recombinant mammalian cell lines. | the production of glycosylated forms of the human t cell growth factor (interleukin-2, il-2) has been studied after transfection of a mouse l cell line and a chinese hamster ovary cell line with a plasmid containing the human chromosomal interleukin-2 gene. both cell lines produced il-2 constitutively. based on their behavior in reversed-phase l.c. and their sodium dodecyl sulfate-gel-electrophoresis pattern, human il-2 protein secreted by l cells showed a similar distribution of glycosylated (m ... | 1986 | 3489528 |
| effect of light fluence rate on mammalian cells photosensitization by chloroaluminium phthalocyanine tetrasulphonate. | phthalocyanines are photosensitizers evaluated for use in photodynamic therapy of cancer. as such, the dependence of the bioresponse on the light fluence rate may be of clinical importance. the effect of the fluence rate of white light from 0.165 to 3.3 kj m-2 min-1 was studied in chinese hamster cells and human lymphocytes, using as endpoints colony-forming ability and inhibition of [3h]thymidine incorporation following mitogenic stimulation and dye-photoactivation, respectively. using chinese ... | 1987 | 3494699 |
| genetic mapping of the mouse interleukin 3 gene to chromosome 11. | interleukin 3 (il 3) is a t cell-derived lymphokine that induces the proliferation and differentiation of early hematopoietic stem cells. by using a cdna clone for il 3, a single eco-ri restriction fragment of 8.5 kbp was detected in southern blot hybridizations of dna from balb/c and c57bl/10 mice, whereas an eco-ri restriction fragment of 10.8 kbp was detected in nfs and a/j mice. under the conditions used, no hybridization was detected to chinese hamster dna. the species and strain difference ... | 1987 | 3494779 |
| recombinant human gm-csf induces leukocytosis and activates peripheral blood polymorphonuclear neutrophils in nonhuman primates. | the in vivo efficacy of glycosylated and nonglycosylated recombinant human granulocyte macrophage colony-stimulating factor (rh gm-csf) expressed in chinese hamster ovary cells and escherichia coli respectively was studied in rhesus monkeys following a daily subcutaneous (sc; three times) or intravenous (iv; over six hours) dose for seven consecutive days. the monkeys responded to the rh gm-csf with a prompt (within 24 hours) rise in circulating white blood cells (wbcs). thereafter the total cel ... | 1987 | 3496133 |
| interactions of a neuronal cell line (pc12) with laminin, collagen iv, and fibronectin: identification of integrin-related glycoproteins involved in attachment and process outgrowth. | neuronal responses to extracellular matrix (ecm) constituents are likely to play an important role in nervous system development and regeneration. we have studied the interactions of a neuron-like rat pheochromocytoma cell line, pc12, with ecm protein-coated substrates. using a quantitative cell attachment assay, pc12 cells were shown to adhere readily to laminin (ln) or collagen iv (col iv) but poorly to fibronectin (fn). the specificity of attachment to these ecm proteins was demonstrated usin ... | 1987 | 3500175 |
| potentiation of doxorubicin cytotoxicity by the calcium antagonist bepridil in anthracycline-resistant and -sensitive cell lines. a comparison with verapamil. | the ability of the calcium channel blocker bepridil (bp) to potentiate doxorubicin (dx) cytotoxicity and enhance its accumulation in anthracycline-sensitive and -resistant human ovarian carcinoma cells (a2780 and 2780ad) and chinese hamster ovarian (cho) cells (auxb1 and chrc5) was compared with that of verapamil (vp). a continuous exposure (48-72 h) to bp as well as vp potentiated dx cytotoxicity in 2780ad cells. in short-term incubations (2 h dx and 4 h calcium channel blocker) the same effect ... | 1987 | 3500807 |
| toward early diagnosis of myotonic dystrophy: construction and characterization of a somatic cell hybrid with a single human der(19) chromosome. | we have constructed a somatic cell hybrid line, designated 908k1, with a single human der(19) chromosome on a chinese hamster background by employing conventional as well as microcell-mediated cell fusion techniques. the der(19) chromosome comprises the 19p13.1----q13.2 segment, as well as the distal (xq24----qter) portion of the x chromosome long arm, and is stably retained by hat selection. extensive characterization of this hybrid line and comparison with other somatic cell hybrids has enable ... | 1986 | 3502690 |
| superovulation in immature and mature chinese hamsters. | mature female chinese hamsters ovulate an average of 8.8 +/- 1.0 (mean +/- sd) eggs per female in each estrous cycle. superovulation can be induced in both immature and mature females by subcutaneous or intraperitoneal injections of pregnant mare serum gonadotropin (pmsg) and either human chorionic gonadotropin (hcg) or pituitary luteinizing hormone (plh). the best superovulation in immature females was induced by the administration of 15 iu of pmsg followed 72 hr later by injection of 15 iu of ... | 1987 | 3506916 |
| induction of malignant transformation in vitro and mammary tumors in rats by two new potent anthracycline antitumor antibiotics, morpholinodaunomycin and cyanomorpholinoadriamycin. | the two new potent anthracycline antitumor antibiotics, morpholinodaunomycin and cyanomorpholinoadriamycin, are non-mutagenic or weakly mutagenic in salmonella typhimurium or v79 chinese hamster cells, but highly active inducing dna repair in in cultured rat hepatocytes. both agents were found to induce malignant transformation in vitro of c3h m2 mouse fibroblasts and mammary tumors in female sprague-dawley rats. the data indicate a) that these new anthracyclines, too, are highly oncogenic and b ... | 1987 | 3507246 |
| lysosomal involvement in cellular intoxication with clostridium difficile toxin b. | the process of internalisation of clostridium difficile toxin b into human lung fibroblasts was further studied, with the aim of elucidating the fate of endocytosed toxin. development of the toxin-induced cytopathogenic effect was reversibly inhibited at 18 degrees c and in the presence of 200 mm kcl or 1-20 mm benzyl alcohol, i.e. at conditions when the fusion between endosomes and lysosomes is prevented. fibroblasts treated with toxin at 37 degrees c but transferred to 18 degrees c within 10 m ... | 1986 | 3508493 |
| salmonella cytotoxin: a component of the bacterial outer membrane. | salmonella cytotoxin present in cell-free sonic lysates causes rounding and detachment of chinese hamster ovary (cho) cells. although the precise role of this toxin in the pathogenesis of salmonellosis is unclear, cytotoxin production by salmonella could account for tissue damage or possibly, facilitate invasion. a variety of other bacteria (e.g. shigella, escherichia, legionella) have been shown to form soluble cytotoxins, many of which may be involved in pathogenesis. the data in this report i ... | 1986 | 3508497 |
| development of cytotoxicity tests for assessment of the toxicity of water samples taken from the environment. | different methods of measuring cytotoxicity have been investigated in order to establish a test system for assessment of the toxicity of water samples. ideally this should be highly sensitive and rapid to perform. four variations of the neutral red uptake test have been compared with the mtt test and atp determination. chinese hamster v79/4 cells were used as the test system with 10 model toxins. all tests gave essentially similar results, with linear regression analysis producing correlation co ... | 1987 | 3509694 |
| synthesis and mutagenicity of 1-nitro-6-nitrosopyrene and 1-nitro-8-nitrosopyrene, potential intermediates in the metabolic activation of 1,6- and 1,8-dinitropyrene. | 1,6-dinitropyrene and 1,8-dinitropyrene are environmental contaminants which are mutagenic in bacteria and cultured mammalian cells. since nitroreduction, and possibly o-acetylation, have been implicated in the metabolic activation of these compounds, the reduced intermediates, 1-nitro-6-nitrosopyrene and 1-nitro-8-nitrosopyrene, were synthesized and their mutagenicity examined in salmonella typhimurium and chinese hamster ovary (cho) cells. nitration of 1-acetylaminopyrene yielded a mixture of ... | 1986 | 3510751 |
| human luteinizing hormone-releasing hormone gene (lhrh) is located on short arm of chromosome 8 (region 8p11.2----p21). | luteinizing hormone-releasing hormone (lhrh) is synthesized by hypothalamic neurons and affects the release of gonadotropic hormones from the anterior pituitary gland. a cdna clone encoding the human lhrh precursor molecule was used to assign the lhrh gene to a human chromosome by in situ hybridization and southern blot analysis. metaphase spreads from two normal individuals were hybridized with 3h-labeled lhrh-specific sequence. of 120 cells analyzed, 33 had silver grains over the p11.2----p21 ... | 1986 | 3511544 |
| the influence of plasma insulin concentrations on tissue insulin levels in rodents: a study of the diabetic chinese hamster and the ob/ob mouse. | immunoreactive insulin was measured in acid-ethanol extracts of kidney, brain, liver, and heart from genetically diabetic chinese hamsters and their nondiabetic controls and from obese (ob/ob) mice and their thin littermates. selected samples were filtered on sephadex g-50 columns and the insulin concentration determined. there was a good correlation between the insulin level measured in the acid-ethanol extracts of tissues and the insulin level after gel filtration, suggesting that the concentr ... | 1986 | 3512956 |
| quantitative and molecular analyses of ethyl methanesulfonate- and icr 191-induced mutation in as52 cells. | a psv2gpt-transformed chinese hamster ovary (cho) cell line has been used to study mutation at the molecular level. this cell line, designated as52, was constructed from a hypoxanthine-guanine phosphoribosyl transferase (hprt)-deficient cho cell line, and has been previously shown to contain a single, functional copy of the e. coli xanthine-guanine phosphoribosyl transferase (xprt) gene (gpt) stably integrated into the chinese hamster genome. in this study, conditions for its use in the study of ... | 1986 | 3512985 |