Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
|---|
| purine mutants of mammalian cell lines: iii. control of purine biosynthesis in adenine phosphoribosyl transferase mutants of cho cells. | spontaneous and mutagen-induced 2,6-diaminopurine-resistant mutants of chinese hamster ovary (cho-k1) cells were isolated. such mutants fell into two classes: spontaneous and ethylmethane-sulfonate-induced mutants had approximately 5% wild-type adenine phosphoribosyl transferase (aprt) activity, whereas icr-170g-induced mutants had barely detectable aprt activity. since it has been reported that human hypoxanthine-guanine phosphoribosyl transferase (hgprt) (lesch-nyhan syndrome) and aprt mutants ... | 1977 | 75575 |
| the expression and relation of hla, beta2-microglobulin and receptor for marmoset red blood cells on man/mouse and man/chinese hamster hybrid cells. | the expression of hla, human and mouse beta2-microglobulin (beta2m), p red blood cell antigen and a receptor for marmoset red blood cells (marbc) were studied on 18 man/mouse and man/chinese hamster hybrids. a positive correlation was found between the expression of hla, p, and the receptor for marbc, which we interpret as a possible synteny between these different loci. we studied 3 hybrid clones where hla antigens are still expressed despite the absence of human beta2m and where redistribution ... | 1977 | 66148 |
| pretreatment of hamster cells with phenethyl alcohol alters cell surface glycoproteins and inhibits vesicular stomatitis virus growth. | chinese hamster ovary cells cultured in the presence of phenethyl alcohol exhibit obvious changes in cell surface galactose and galactosamine glycoproteins as determined by the galactose-oxidase[3h]borohydride technique and sds gel electrophoresis. cells pretreated with phenethyl alcohol (drug was removed before infection) were not as effective as hosts for vesicular stomatitis virus as untreated cultures. a minimum pretreatment time with 0.1% phenethyl alcohol of about 8 h was required before a ... | 1977 | 68807 |
| identification of a chromosome that controls malignancy in chinese hamster cells. | a chromosome that controls malignancy in chinese hamster cells has been identified by analysis of the giemsa banding pattern of a malignant cell line transformed by simian virus 40 (sv40), non-malignant revertants from this line, segregants from the revertants that were again malignant and a cell line transformed by methylcholanthrene. the malignant cell line transformed by sv40 was near diploid and had gained additional material of chromosome 3. revertants with a suppression of malignancy and m ... | 1977 | 73545 |
| further studies on hybrid cell-surface antigens associated with human chromosome 11. | a new human immunogenetic cell-surface activity associated with human chromosome 11 in the al human-chinese hamster ovary cell hybrid is described. like a1, but not a2, it is present on the human erythrocyte. by mutagenesis and selection, specific, stable, variants of the al hybrid have been prepared exhibiting various combinations of a1, a2, a3, and lactic dehydrogenase a activities. the antigens of the al system can be demonstrated by the horseradish peroxidase system which offers a promising ... | 1977 | 74861 |
| assignment of the genes for thymidine kinase and galactokinase to mus musculus chromosome 11 and the preferential segregation of this chromosome in chinese hamster/mouse somatic cell hybrids. | 1977 | 204065 | |
| chromosomal alterations in a chinese hamster cell line transformed in vitro by sv40 virus. | 1977 | 200554 | |
| a comparison of camp phosphodiesterases in normal, malignant, and somatic cell hybrids. | hybrids (pcm) between a malignant mouse lymphoma suspension cell line (p388f-36) and a normal chinese hamster fibroblastic cell line (ch23) have already been isolated in this laboratory. investigations were carried out on the camp phospodiesterases of the parents and two of these hybrids--pcm2 and pcm3. pcm3 shows a rather unusual growth characteristic in that a considerable proportion of the cells exist at any one time either in suspension or only loosely attached to the substratum, the remaini ... | 1977 | 201244 |
| simian virus 40-chinese hamster kidney cell interaction. iii. characteristics of chemical induction in a clone of virogenic transformed cells. | a number of chemical and physical agents were screened to determine their effectiveness in inducing simian virus (sv40) production in a virogenic clone of sv40-transformed chinese hamster cells. mitomycin c (mc) was the most effective inducing agent, and mc induction was further characterized. it was found that levels of infectious sv40 dna were increased above control levels as early as 6 h after addition of mc to the culture medium and reached maximum levels by 48 h. virus capsid (v) antigen a ... | 1977 | 196036 |
| cyclic amp and insulin release. | the role of cyclic adenosine-3',5'-monophosphate (camp) for insulin secretion has been investigated. in isolated islets of langerhans from the rat, glucose increases camp concomitant with insulin secretion. stimulation of these two parameters is likewise reversible in parallel. the minimal and maximal concentrations of glucose eliciting camp and insulin responses are similar. isomers and epimers of glucose influence insulin and camp in a parallel fashion as do sulfonylurea compounds (tolbutamide ... | 1977 | 210617 |
| simian virus 40-chinese hamster kidney cell interaction. iv. enhanced virus replication in infected cells upon treatment with mitomycin c. | chinese hamster kidney cells are semi-permissive to simian virus 40 (sv40). exposure to mitomycin c (mc) of chinese hamster kidney cells infected with sv40 dna enhanced the yield of infectious virus 10- to 100-fold. this stimulation occurred whether the treatment was performed before or after infection. a simultaneous increase in the number of v antigen-synthesizing cells and virus-producing cells, as well as the virus burst size, was observed upon mc pretreatment, whereas the proportion of t an ... | 1977 | 196038 |
| transfer of the human genes coding for thymidine kinase and galactokinase to chinese hamster cells and human-chinese hamster cell hybrids. | cotransfer of two linked human genes, coding for the enzymes thymidine kinase (tk) and galactokinase (gak) was demonstrated following incubation of chinese hamster tk-deficient cells with isolated human chromosomes. the 5 colonies which were isolated all expressed a stable tk-positive phenotype. cotransfer of the human genes coding for tk and gak has also been observed in experiments in which isolated human chromosomes were incubated with tk-deficient human-chinese hamster cell hybrids. these re ... | 1977 | 204067 |
| an investigation of the homology of guanylate kinase isozymes in mammals and further evidence for multiple guk gene loci. | guanylate kinase in the red cells of 63 different mammalian species was studied by electrophoresis and multiple molecular forms of the enzyme were found in all species. two species were investigated in more detail. using molecular weight estimates as a criterion of homology, the fallow deer and the chinese hamster were found to have isozymes that corresponded to isozyme e, f, and g of man. variation in the guanylate kinase isozymes was detected in a small population of orangutans. results sugges ... | 1977 | 201245 |
| effects of temperature and antibody on the cyclid growth of vesicular stomatitis virus. | to see the effects of temperature on the interrelated cyclic production of standard and defective interfering (di) particles of vesicular stomatitis virus, a temperature-sensitive (ts) g114 mutant was passaged successively at different temperatures and the production of the two types of viral particles as well as the ability of chinese hamster ovary cells to survive each passage was continuously monitored. when the temperature was nonpermissive for standard virus, the synthesis of both standard ... | 1977 | 189064 |
| assembly of viral membranes. i. association of vesicular stomatitis virus membrane proteins and membranes in a cell-free system. | we report here an in vitro system designed to study the interactions of vesicular stomatitis virus (vsv) proteins with cellular membranes. we have synthesized the vsv nucleocapsid (n) protein, nonstructural (ns) protein, glycoprotein (g protein), and membrane (m) protein in a wheat germ, cell-free, protein-synthesizing system directed by vsv 12 to 18s rna. when incubated at low salt concentrations with purified cytoplasmic membranes derived from chinese hamster ovary cells, the vsv m andg protei ... | 1977 | 189082 |
| assignment of the integration site for simian virus 40 to chromosome 17 in gm54va, a human cell line transformed by simian virus 40. | gm54va human cells transformed by simian virus 40 (sv40) were fused with peritoneal macrophages obtained from three different mouse strains. all 27 hybrid clones studied were positive for sv40 tumor antigen in 100% of their cells and contained human chromosome 17. human chromosome 17 was the only human chromosome present in five of the hybrid clones. fusion of gm54va cells and either thymidine kinase (ec 2.7.1.75)-deficient mouse or chinese hamster fibroblasts resulted in the growth in hypoxanth ... | 1977 | 189310 |
| variation in enterotoxigenicity of escherichia coli. | the possibility that the variable severity of diarrheal disease due to enterotoxigenic escherichia coli might be explained by quantitative differences in the activity of heat-labile enterotoxin was examined. the amount of toxin secreted by 13 enteropathogenic strains of e. coli was quantitated by measurements of the toxin-dependent increase in adenosine 3':5'-cyclic phosphate (cyclic amp) in chinese hamster ovary cells. the activity ranged from 150 pmol of cyclic amp/ml per mg of protein to 4,04 ... | 1977 | 190329 |
| heterogeneity of karyotype and growth potential in simian virus 40-transformed chinese hamster cell clones. | five clones of chinese hamster cells transformed with simian virus 40 (sv40) were isolated from methylcellulose and characterized as to giemsa-banded karyotype, dna content, saturation density, agglutination with concanavalin a, and tumorigenicity. chromosome analysis and dna content studies at early passage revealed that the genetic complement for all clones was predominantly near tetraploid. all cultures examined contained a proportion of hypertetraploid cells. nonrandom chromosome changes inc ... | 1977 | 192902 |
| mechanism of action of inosine dialdehyde (nsc 118994) in the inhibition of proliferation of tumor cells in culture. | inosine dialdehyde (inox), the periodate oxidation product of inosine, inhibited the proliferation of various tumor cell lines in suspension culture in a concentration-dependent manner. a concentration of about 1 mm was required to completely inhibit the proliferation of novikoff rat hepatoma and mouse l-cells, whereas about 0.1 mm completely inhibited the proliferation of l1210 and p388 mouse leukemia and chinese hamster ovary cells. inox inhibited in a similar time- and concentration-dependent ... | 1977 | 193637 |
| correlation between changes in intracellular level of cyclic amp, activation of cyclic amp-dependent protein kinase, and the morphology of chinese hamster ovary cells in culture. | 1977 | 196552 | |
| purineless death: ribosomal rna turnover in a purine-starved ade- mutant of chinese hamster cells. | when v79 pur 1, a purine-requiring auxotroph of a chinese hamster cell line, is deprived of adenine, nucleic acid and protein synthesis decline rapidly. however, on continuous starvation rna and dna synthesis recommences to reach approximately 30% of the normal level between 12 to 24 h starvation. this is accompanied by a rise in the intracellular nucleotide pool. utilizing mengovirus, which gives a productive infection in v79 pur 1 cells even under conditions of starvation, we can show that rrn ... | 1977 | 195948 |
| effect of staphylococcus aureus delta toxin on chinese hamster ovary cell morphology and y-1 adrenal cell morphology and steroidogenesis. | since staphylococcus aureus delta toxin previously had been shown to increase the cyclic adenosine 3',5'-monophosphate (camp) content of guinea pig ileum, the effect of delta toxin on such camp-mediated responses as morphogenesis and steroidogenesis in cultured tissue cells was examined. in contrast to cholera toxin, delta toxin did not cause spindling of chinese hamster ovary cells. unlike adrenocorticotropin or cholera toxin, delta toxin was unable to cause rounding of y-1 adrenal cells or to ... | 1977 | 197006 |
| gene mapping in mus musculus by interspecific cell hybridization: assignment of the genes for tripeptidase-1 to chromosome 10, dipeptidase-2 to chromosome 18, acid phosphatase-1 to chromosome 12, and adenylate kinase-1 to chromosome 2. | chinese hamster x mouse somatic cell hybrids segregating mouse chromosomes were examined for their mouse chromosome content using trypsin-giemsa (gtg) banding and hoechst 33258 staining techniques. simultaneously, they were scored for the presence of 24 mouse enzymes. the results confirm the assignments of 11 genes previously mapped by sexual genetics: dip-1 and id-1 to chromosome 1; pgm-2 and pgd to 4; pgm-1 to 5; gpi-1 to 7; gr-1 to 8; mpi-1 and mod-1 to 9; np-1 and es-10 to 14. they also conf ... | 1977 | 198184 |
| virus production with a newly developed microcarrier system. | primary cell cultures as well as established lines have been grown on a recently developed microcarrier configuration that overcomes the problem of toxicity attendant on earlier developments in this technology. virus yields from these cells propagated on the new microcarriers have been measured. microcarrier-grown cells, when compared to roller-bottle-grown cells, gave virus yields on a per-cell basis that varied from slightly greater with the sindbis virus-chinese hamster ovary cells and polio- ... | 1977 | 202193 |
| initiation points for dna replication in nontransformed and simian virus 40-transformed chinese hamster lung cells. | randomly growing chinese hamster lung cells were pulse-labeled with 3h-thymidine, and the replicating forks of individual dna fibers were visualized by autoradiography. when grown in complete medium, wild-type sv40-transformed cells had more forks per unit length of dna than nontransformed cells. in isoleucine-depleted medium, wild-type sv40-transformed cells had fewer forks per unit length than those few nontransformed cells (1-3% of the population) which continued dna replication. cells transf ... | 1977 | 196764 |
| synteny of the genes for thymidine kinase and galactokinase in the mouse and their assignment to mouse chromosome 11. | we have studied the expression of mouse galactokinase in human-mouse somatic cell hybrids segregating mouse chromosomes. since concordant segregation of the expression of mouse galactokinase and the presence of mouse chromosome 11 were observed in the hybrid clones, we conclude that the gene for mouse galactokinase is located on mouse chromosome 11. we have also investigated the expression of mouse galactokinase in somatic cell hybrids between thymidine kinase-deficient chinese hamster cells and ... | 1977 | 196814 |
| serial transfer of a human gene to rodent cells by sequential chromosome-mediated gene transfer. | the human hypoxanthine phosphoribosyl-transferase (imp:pyrophosphate phosphoribosyltransferase, ec 2.4.2.8) gene (hprt) has been serially transferred to mouse cells and then to chinese hamster fibroblasts by two cycles of metaphase chromosome isolation and incubation with recipient cells. human metaphase chromosomes were incubated with mouse a9 cells deficient in hypoxanthine phosphoribosyltransferase, and independent colonies expressing the human species form of this gene were isolated in a sel ... | 1977 | 268645 |
| stable association of the human transgenome and host murine chromosomes demonstrated with trispecific microcell hybrids. | trispecific microcell hybrids were prepared by transferring limited numbers of chromosomes from a human/mouse gene-transfer cell line to a chinese hamster recipient line. the donor cells employed were murine l-cells that stably expressed the human form of the enzyme hypoxanthine phosphoribosyltransferase. karyotypic, zymographic, and back-selection tests of the resulting human/mouse/chinese hamster microcell hybrids provided strong genetic evidence for a stable association of the human transgeno ... | 1977 | 269444 |
| mutation induction by the antischistosomal drug f30066 in various test systems. | the genetic activity of furapromidium (f30066), an antischistosomal drug, was studied in salmonella typhimurium, saccharomyces cerevisiae, neurospora crassa and cultured chinese hamster cells. the results show that f30066 induces gene mutations in s. typhimurium, n. crassa and chinese hamster cells. this compound also causes gene conversions in s. cerevisiae. | 1977 | 138086 |
| assignment of the human gene for galactose-1-phosphate uridyltransferase to chromosome 9: studies with chinese hamster-human somatic cell hybrids. | chinese hamster-human somatic cell hybrids were analyzed for the expression of human galactose-1-phosphate uridyltransferase (galt; udpglucose:alpha-d-galactose-1-phosphate uridyltransferase, ec 2.7.7.12) by electrophoresis and for the presence of human chromosomes cytogenetically with the aid of q-banding. three of the 10 randomly chosen independently derived primary hybrid lines showed the presence of human galt. human chromosome 9 was consistently present in the hybrid lines expressing human ... | 1977 | 271990 |
| microcell-mediated transfer of murine chromosomes into mouse, chinese hamster, and human somatic cells. | in this report, we describe the production and characterization of proliferating hybrid cell populations generated by fusion of murine microcells with intact mouse, chinese hamster, and human recipient cells. the microcell hybrids so produced contained one to five intact murine chromosomes derived from the microcell donor. these transferred chromosomes were maintained as functioning genetic elements in the hybrid cells. our results firmly establish subnuclear particle-mediated chromosome transfe ... | 1977 | 264685 |
| assignment of the major histocompatibility complex to a region of the short arm of human chromosome 6. | interspecific cell hybrids containing defined parts of human chromosome 6 were used for regional mapping of gene loci previously assigned to chromosome 6: the human leukocyte antigens (hla) region, phosphoglucomutase-3 (pgm3; alpha-d-glucose-1,6-bisphosphate:alpha-d-glucose-1-phosphate phosphotransferase, ec 2.7.5.1) and malic enzyme-1 [malic dehydrogenase(decarboxylating) (nadp+), l-malate:nadp+ oxidoreductase (oxaloacetate-decarboxylating), ec 1.1.1.40]. human fibroblasts containing a balanced ... | 1977 | 265561 |
| rescue of marker phenotypes mediated by somatic cell hybridization. | the effect of irradiation prior to virus-induced cell fusion on the frequency of hybrid production has been measured as a function of radiation dose. the chinese hamster line wg3h (hgprt-) was crossed with the tk- mutants; chinese hamster a23 or mouse 3t34e, and hybrids were selected in hat medium. irradiation of one (marker rescue) or both (mutual rescue) partners before fusion yielded qualitatively different results. after x-irradiation marker rescue curves were of single-hit type, with d0 val ... | 1977 | 300369 |
| comparison of three mammalian cell-lines with respect to their sensitivities to hyperthermia, gamma-rays and u.v.-radiation. | three types of cultured mammalian cells, from a rat ureter carcinoma (ruc-2), from a mouse mammary carcinoma (m8013), and from a chinese hamster lung cell-line (ch-v79), have been compared with respect to various treatments. using cloning assay, the sensitivity of these cell-lines was measured for ionizing radiation, u.v.-light and for temperatures of 41 degrees, 42 degrees, 43 degrees, 44 degrees and 45 degrees c. ruc-2 cells are the least sensitive to these treatments, except for 45 degrees c. ... | 1977 | 301514 |
| inactivation and mutation of cultured mammalian cells by aluminium characteristic ultrasoft x-rays. ii. dose-responses of chinese hamster and human diploid cells to aluminium x-rays and radiations of different let. | the induction of inactivation and mutation to thioguanine-resistance of two types of cultured mammalian cells, v79 chinese hamster and hf19 human diploid, was studied after irradiation with aluminium k characteristic ultrasoft x-rays, helium ion track intersections of different let, 42 mev d-be neutrons, and hard x- or gamma-rays. the form of the dose-response curves was different for the two cell-types, and there was an overall difference in radiosensitivity, the human cells being the more sens ... | 1977 | 301865 |
| inactivation and mutation of cultured mammalian cells by aluminium characteristic ultrasoft x-rays. iii. implication for theory of dual radiation action. | microdosimetric distributions for aluminium k characteristic ultrasoft x-rays and 4he ion tract intersections are calculated and used to analyse recent biological results obtained with these radiations. results on inactivation and mutation-induction to thioguanine resistance of both v79 chinese hamster cells and hf19 human diploid fibroblasts in vitro are analysed in terms of the kellerer-rossi "theory of dual radiation action". the small quantum energy of the aluminium x-ray photons and the ver ... | 1977 | 301870 |
| effect of salt solutions on radiosensitivity of mammalian cells. iii. treatment with hypertonic solutions. | v79 chinese hamster cells were treated with hypertonic solutions of nacl or kcl and irradiated rat various times before, during, or after exposure to the solution. in solutions of molarities between 0-2 and 0-5 m, the cellular radiosensitivity increases with the molarity of the bathing solution. at these molarities, the hypertonic solution need not be present during irradiation to sensitize cells. furthermore, radiosensitivity of cells could be increased by exposing cells for longer times to the ... | 1977 | 302244 |
| regional assignment of seven genes on chromosome 1 of man by use of man-chinese hamster somatic cell hybrids. ii. results obtained after induction of breaks in chromosome 1 by x-irradiation. | the position of genes coding for pgd, pph1, ugpp, guk1, pgm1, pep-c, and fh on human chromosome 1 was investigated by analysis of karyotype and enzyme phenotypes in man-chinese hamster somatic cell hybrids carrying aberrations involving chromosome 1. suitable hybrid cell lines were obtained by x-irradiation of hybrid cells carrying an intact chromosome 1 and by fusion of human cells from a clonal population carrying a translocation involving chromosome 1 with chinese hamster cells. the latter hu ... | 1977 | 318153 |
| mannosidosis: assignment of the lysosomal alpha-mannosidase b gene to chromosome 19 in man. | human alpha-mannosidase activity (alpha-d-mannoside mannohydrolase, ec 3.2.1.24) from tissues and cultured skin fibroblasts was separated by gel electrophoresis into a neutral, cytoplasmic form (alpha-mannosidase a) and two closely related acidic, lysosomal components (alpha-mannosidase b). human mannosidosis, an inherited glycoprotein storage disorder, has been associated with severe deficiency of both lysosomal alpha-mannosidase b molecular forms. chromosome assignment of the gene coding for h ... | 1977 | 318154 |
| the effect of respiratory carcinogenesis on systemic humoral and cell-mediated immunity of syrian golden hamsters. | the effect of intratracheal instillation of benzo(a)pyrene and its noncarcinogenic analog benzo(a)pyrene on the systemic humoral and cell-mediated immune response of syrian golden hamsters was evaluated. hamsters treated with the carcinogen had a transient suppression of the splenic plaque-forming cell response to sheep erythrocytes, compared with analog-treated controls. the numbers of direct (immunoglobulin m) and indirect (immunoglobulin g) plaque-forming cells were suppressed at the 9th week ... | 1977 | 318605 |
| enterotoxigenic escherichia coli isolated from patients at a hospital in dacca. | enterotoxigenic strains of escherichia coli, a significant cause of acute, watery, cholera-like diarrhea, were isolated from 23 of 65 patients with diarrhea in whom no other enteric pathogens were found during one week (november 1974) at the cholera research hospital, dacca, bangladesh. diarrhea associated with enterotoxigenic strains of e. coli occurred primarily in adults but affected persons of all age groups and could not be distinguished from cholera or from other cholera-like diarrhea on c ... | 1977 | 320276 |
| diarrhea due to escherichia coli in the rabbit: a novel mechanism. | a strain of escherichia coli o15 (rdec-1) isolated from several rabbits with diarrhea was examined to determine (1) whether the strain could produce diarrhea when administered by the orogastric route to other rabbits and (2) whether this strain was invasive or enterotoxigenic. strain rdec-1 produced diarrhea in 48 of 62 rabbits when given by the orogastric route in doses that ranged from 1.5 x 10(2) to 4 x 10(10) bacteria. the organism did not give a positive result in the 18-hr ileal loop or se ... | 1977 | 321703 |
| mutagenicity of polycyclic hydrocarbons. ii. monitoring genetical hazards of chrysene in vitro and vivo. | mutagenicity tests were performed with chrysene in the salmonella/microsome test, nmri-mice oocytes, bone-marrow cells and spermatogonia of chinese hamsters. only in mice oocytes was a weak but significant increase of structural chromosome aberrations observed. correlations were found between weak carcinogenic and observed weak mutagenic activities of chrysene in vitro and in vivo. | 1977 | 327309 |
| mutagenicity and cytotoxicity of benz[alpha]anthracene diol epoxides and tetrahydro-epoxides: exceptional activity of the bay region 1,2-epoxides. | three diastereomeric pairs of diol epoxides, two tetrahydro-epoxides, and the k-region oxide of the polycyclic aromatic hydrocarbon benz[a]anthracene were evaluated for mutagenic activity in strain ta 100 of salmonella typhimurium and in line v79-6 of chinese hamster lung cells. the two diastereomeric 1,2-epoxides of the trans-3,4-dihydrodiol of benz[a]anthracene are 15 to 35 times more mutagenic to the bacteria and 65 to 125 times more mutagenic to the mammalian cells than are the diastereomeri ... | 1977 | 331315 |
| mutagenicity of isomeric diol-epoxides of benzo[a]pyrene and benz[a]anthracene in s. typhimurium ta98 and ta100 and in v79 chinese hamster cells. | pairs of isomeric vicinal diol-epoxides derived from benzo[a]pyrene 7,8- and 9,10-dihydrodiols and from benz[a]anthracene 8,9-dihydrodiol were tested for their abilities to revert salmonella typhimurium strains ta98 and ta100 to histidine prototrophy and to induce the formation of 8-azaguanine- or of ouabain-resistant v79 chinese hamster cells. all six diol-epoxides were active in both bacterial strains, but 7beta,8alpha-dihydroxy-9beta,10beta-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (the syn iso ... | 1977 | 333280 |
| characterization of the chinese hamster ovary cell assay for the enterotoxins of vibrio cholerae and escherichia coli and for specific antisera, and toxoid. | the morphologic change in chinese hamster ovary (cho) cells that is associated with increased intracellular concentrations of adenosine 3':5'-cyclic phosphate (cyclic amp) provided a highly sensitive assay for the heat-liable enterotoxins of vibrio cholerae and escherichia coli. the similarity between the responses of cho cells and those of intestinal mucosa to enterotoxins was demonstrated by the inhibition of these effects by the ganglioside galactosyl-n-acetylgalactosaminyl [sialosyl] lactosy ... | 1977 | 323378 |
| zinc and manganese contents of micro-dissected pancreatic islets of some rodents. a microchemical study in adult and newborn guinea pigs, rats, chinese hamsters and spiny mice. | by a flameless atomic absorption spectrophotometry procedure, using a graphite furnace, it was possible to assay the contents of zinc and managanese in micro-dissected pancreatic islets of several rodents. interest was focused upon the islets of guinea-pigs, due to the fact that guinea-pig insulin lacks a histidine residue in the b10 position of the molecule which normally binds zinc (or other heavy metals) in the hexamer formation, probably involved in the storage of insulin. both the zinc and ... | 1977 | 335757 |
| toxin from the culture filtrate of shigella dysenteriae that causes morphological changes in chinese hamster ovary cells and is distinct from the neurotoxin. | a toxin that causes morphological changes in chinese hamster ovary cells was isolated from a culture filtrate of shigella dysenteriae 1. it was partially purified by successive column chromatography on diethylaminoethyl-cellulose, bio-gel a-5m, and hydroxylapatite. the toxin was separated from neurotoxin by diethylaminoethyl-cellulose column chromatography and was not lethal for mice. | 1977 | 336549 |
| inhibition of mammalian ribonucleotide reductase by a dinucleotide produced in eucaryotic cells. | hs3, a highly phosphorylated dinucleoside originally purified from the fungus achlya, has been isolated from chinese hamster ovary cells undergoing glutamine starvation. the hs3 compounds obtained from the fungal and mammalian sources exhibited similar physical and chemical properties. this unusual dinucleotide may be an important regulator of eucaryotic ribonucleoside diphosphate reductase activity; for 50 micrometer hs3, isolated from either mammalian or fungal cells, significantly inhibited c ... | 1977 | 338619 |
| escherichia coli heat-labile enterotoxin: comparison of antitoxin assays and serum antitoxin levels. | the mouse adrenal tumor cells (y-1 strain) and the chinese hamster ovary cells, two routinely used tissue culture assays for escherichia coli heat-labile enterotoxin (lt), were used to detect serum antitoxin responses in culture-positive patients from several well-defined sources. there was no correlation between a significant antitoxin response and isolation of lt-producing e. coli in two "domestic" diarrheal outbreaks. serum samples from a third group of individuals in a rural cholera-endemic ... | 1977 | 336543 |
| microsome-mediated mutagenesis in v79 chinese hamster cells by various nitrosamines. | a microsome-mediated mutagenesis system has been established with the v79 chinese hamster cell line. the cells, grown in monolayer, were treated with various nitrosamines in the presence of a postmitochondrial fraction ((s15) from rat liver and a reduced nicotinamide adenine dinucleotide-generating system for 1 hr, washed and incubated for 2 to 3 hr in fresh culture medium, and then plated for toxicity and mutagenicity assays. mutation was determined by resistance to 20mug 8-azaguanine per ml. i ... | 1977 | 321116 |
| assignment of the structural genes for the alpha subunit of hexosaminidase a, mannosephosphate isomerase, and pyruvate kinase to the region q22-qter of human chromosome 15. | concordant segregation of the expression of the alpha subunit of human hexosaminidase a, human mannosephosphate isomerase, and pyruvate kinase was observed in somatic cell hybrids between either thymidine kinase-deficient mouse cells or thymidine kinase-deficient chinese hamster cells and human white blood cells carrying a translocation of the distal half (q 22-qter) of the long arm of chromosome 15 to chromosome 17. a positive correlation was established between the expression of these human ph ... | 1977 | 341373 |
| influenza virus infection of a cell-cycle mutant of chinese hamster ovary cells. | 1977 | 558282 | |
| replication of minute virus of mice in chinese hamster ovary fibroblasts. | minute virus of mice (mvm), a parvovirus, replicates in chinese hamster ovary (cho) cells. although replication of the virus cannot readily be detected by haemagglutination, it can be measured by plaque assay on mouse strain lm cells. | 1977 | 560425 |
| assay of escherichia coli heat-labile enterotoxin with vero cells. | the continuous cell line of african green monkey kidney, vero, showed characteristic morphological changes in response to culture filtrates from toxigenic strains of escherichia coli. the response compared favorably with that of y-1 (mouse adrenal) and cho (chinese hamster ovary) cells. vero cells were the simplest and most economical to maintain in the laboratory. | 1977 | 405326 |
| selection and characterization of cells resistant to diphtheria toxin and pseudomonas exotoxin a: presumptive translational mutants. | two classes of diphtheria toxin-resistant variants were selected from chinese hamster ovary (cho-k1) cells: permeability variants, in which uptake of toxin was impaired, and a new class of cytoplasmic variants, which were cross-resistant to pseudomonas exotoxin. ef-2 prepared from the cytoplasmic variants was resistant to adp-ribosylation by either toxin. the evidence presented suggests that these are translational variants possessing a mutationally altered ef-2 gene product. these studies also ... | 1977 | 408012 |
| localization of neurotensin-immunoreactive cells in the small intestine of man and various mammals. | antibodies against synthetic bovine neurotensin were raised in rabbits and used to demonstrate neurotensin-immunreactive cells by immunohistochemical methods. in the jejunum and ileum of all species investigated (man, dog, monkey, cat, rabbit, sheep, rat, mouse, hamster, chinese hamster, gerbil, pig and guinea pig) cells were present in the mucosa, which reacted specifically with antineurotensin serum using the indirect immunofluorescence and peroxidase-antiperoxidase methods. in the monkey tupa ... | 1977 | 409699 |
| characterization of alpha-galactosidase isoenzymes in normal and fabry human-chinese hamster somatic cell hybrids. | the alpha-galactosidases in normal man-chinese hamster somatic cell hybrids were investigation with antibodies specific for human alpha-galactosidase a and antibodies specific for chinese hamster alpha-galactosidase. it was found that an isoenzyme in hybrid cells, which has an electrophoretic mobility between that of human alpha-galactosidase a and chinese hamster alpha-galactosidase, contains immunologic determinants of both human and chinese hamster origin, suggesting that it is a heteropolyme ... | 1977 | 404232 |
| characterization of residual hexosaminidase activity in sandhoff's disease using man-chinese hamster cell hybrids. | to obtain information about the nature of the residual hexosaminidase activity in sandhoff's disease, hybrid cell lines between fibroblasts from a patient with sandhoff's disease and chinese hamster cells were isolated. in these hybrid cell lines, a heteropolymeric isoenzyme was detected that is composed of human alpha- and chinese hamster hexosaminidase subunits. due to the electrophoretic and immunological behavior of the heteropolymeric molecules in interspecies hybrids with normal fibroblast ... | 1977 | 413781 |
| regional localization of a beta-galactosidase locus on human chromosome 22. | human white blood cells with an x/22 translocation [46, xx, t(x;22)(q23;q13)] were fused with chinese hamster cells. the isolated hybrids were analyzed for human chromosomes and 21 enzyme markers. an electrophoretic technique for studying the beta-galactosidase isoenzymes in man-chinese hamster hybrid cells was developed. immunological studies showed that the beta-galactosidase marker studied in these hybrids did contain immunological determinants of human origin. furthermore the results provide ... | 1977 | 414365 |
| human beta-glucuronidase: assignment of the structural gene to chromosome 7 using somatic cell hybrids. | beta-glucuronidase (gus) has become an important enzyme model for the genetic study of molecular disease, enzyme realization, and therapy, and for the biogenesis and function of the lysosome and lysosomal enzymes. the genetics of human beta-glucuronidase was investigated utilizing 188 primary man-mouse and man-chinese hamster somatic cell hybrids segregating human chromosomes. cell hybrids were derived from 16 different fusion experiments involving cells from ten different and unrelated individu ... | 1977 | 559490 |
| dna repair in v-79 cells treated with combinations of ultraviolet radiation and n-acetoxy-2-acetylaminofluorene. | earlier experiments on human cells showed that n-acetoxy-2-acetylaminofluorene mimics ultraviolet radiation in biological and repair characteristics and that the amount of repair from a combined treatment was additive. chinese hamster v-79 cells are less proficient than human cells in excision repair of pyrimidine dimers resulting from irradiation. we therefore investigated the combined effects of both agents on repair in v-79 cells to see whether they follow the same pattern as in human cells. ... | 1977 | 560253 |
| a fluence response study of lethality and mutagenicity of white, black, and blue fluorescent light, sunlamp, and sunlight irradiation in chinese hamster ovary cells. | under a set of defined experimental conditions, the fluence response of chinese hamster ovary (cho) cells to various light sources was studied by measuring single-cell survival and mutation to 6-thioguanine (tg) resistance. fluorescent white, black, and blue lights were sightly lethal and mutagenic. sunlamp light was highly lethal and mutagenic, exhibiting these biological effects within 15 sec of exposure under conditions recommended by the manufacturer for human use. lethal and mutagenic effec ... | 1977 | 593289 |
| small numbers in mutagenicity tests. | experimental control material for statistical analysis of the results of the micronuclei test in the mouse (nmri strain) and the chinese hamster and for the host-mediated assay in the mouse (nmri strain) using auxotrophic bacterial strains are presented. the binomial distribution of the micronuclei makes it possible to analyse the sample size according to the formula of cochran and cox (1957). for the host-mediated assay, the experimental principles are given which make it possible to evaluate t ... | 1977 | 578712 |
| segregation of human hypoxanthine phosphoribosyltransferase activity from somatic cell hybrids isolated from fusion of mouse gene transfer cells with chinese hamster cells. | 1977 | 561300 | |
| effects of wheat germ agglutinin on membrane transport. | (1) low concentrations of wheat germ agglutinin are cytotoxic toward several tissue culture lines, including chinese hamster ovary cells, swiss 3t3 cells, mouse l cells and baby hamster kidney cells. the ld50 ranged from 1 to 5 microgram wheat germ agglutinin per ml. similar concentrations of the lectin inhibited the transport of the non-utilizable amino acids alpha-aminoisobutyric acid and cycloleucine and inhibited the uptake of thymidine. in contrast, 2-deoxy-d-glucose uptake was not altered ... | 1977 | 561616 |
| turnover of tubulin and the n site gtp in chinese hamster ovary cells. | radioactively labeled tubulin from chinese hamster ovary (cho) cells can be isolated by co-polymerization with nonradioactive porcine brain microtubule protein. 75% of the soluble tubulin in cho extracts co-polymerizes with the porcine protein through several cycles, without preferential loss of either cho or porcine subunits. after phosphocellulose chromatography of the co-polymerized microtubules, the cho tubulin is radiochemically homogeneous, as judged by sds-polyacrylamide gel electrophores ... | 1977 | 562716 |
| mutagenicity testing in industry. | the aims of authorities, university and industrial scientists are outlined. the prime feature remains: how important are the achieved results for estimating the mutagenic risk to humans? the various methods available for the testing of chemical substances for mutagenicity are compared. their usefulness to estimate the mutagenic risk are considered and the disadvantages and advantages of such methods are discussed. the industrial toxicologist must apply those methods which permit the most accurat ... | 1977 | 578711 |
| streptozotocin-induced diabetes in the chinese hamster. biochemical and endocrine disorders. | streptozotocin treatment (125 mg/kg) in the chinese hamster induced hyperglycaemia, hypoinsulinaemia, hyperglucagonaemia and changes in body, liver, pancreas, stomach, kidney and adipose tissue weights. the pancreatic reserves of insulin and glucagon in the diabetic animals were low, but stomach glucagon high. these animals showed high levels of phosphoenolpyruvate carboxykinase and low levels of glucokinase, hexokinase, isocitrate dehydrogenase and malic enzyme, but normal levels of pyruvate ki ... | 1977 | 590651 |
| cytotoxicity of commonly used solvents at elevated temperatures. | at 43 degrees c (but not at 41 degrees c), organic solvents used to dissolve water-insoluble chemotherapeutic agents become themselves lethal to cells. this finding is not unique to chinese hamster cells (ha-1); mouse mammary sarcoma cells (emt-6) behave similarly. the solvent concentrations involved are in the range of those needed to make drug solutions. hence experiments measuring drug-cell interactions at elevated temperatures must include controls which independently measure solvent effects ... | 1977 | 591566 |
| chromosome stability in cho cells. | the established cell line derived many years ago from chinese hamster ovary (cho cells) has been studied for the extent of chromosomal variation. because this cell line is used extensively for genetic studies, the contribution of chromosome variability to genetic variability has also been examined. the quasidiploid cho cells were found to have a banded karyotype somewhat altered from that of the chinese hamster from which the line was derived. however, most of the genome could be accounted for a ... | 1977 | 601677 |
| intrachromosomal gene mapping in man: the gene for tryptophyl-trna synthetase maps in region q21 leads to qter of chromosome 14. | a gene for tryptophanyl-trna synthetase (ec 6.1.1.2), the enzyme which attaches tryptophan to its trna, has previously been assigned to human chromosome 14 by analysis of man-mouse somatic cell hybrids. we report here a method for the electrophoretic separation of chinese hamster and human tryptophanyl-trna synthetases and its application to a series of independently derived chinese hamster-human hybrids in which part of the human chromosome 14 has been translocated to the human x chromosome. wh ... | 1977 | 564085 |
| visualization of interphase chromosomes. | using a modified giemsa-banding technique we have observed what appear to be chromosomes during interphase in nuclei from allium cepa root tips and chinese hamster cells (cho line). during telophase through g1 chromosomes progressively uncoil and decondense. during s chromosomes are comparatively decondensed, but some segments have structure similar to chromosomes in g1 and g2. during g2 the chromosomes progressively recondense and coil in apparent preparation for prophase. although specific str ... | 1977 | 562895 |
| detection of chemically induced somatic mutation in chinese hamsters. | 1977 | 593291 | |
| comparison of highly inbred diabetic and nondiabetic lines in the upjohn colony of chinese hamsters. | 1977 | 913895 | |
| chromosome studies on bone marrow cells of chinese hamsters fed a radiosterilized diet. | metaphase preparations of chromosomes from bone marrow cells of chinese hamsters were examined for mutagenic effects following the feeding of a radiosterilized diet. no increase in the incidence of structural chromosomal aberrations was observed. as far as numerical aberrrations were concerned, the proportion of cells with polyploidy increased to between 4 to 5 times the control level, irrespective of the moisture content of the diet. this polyploidy effect occurred very early, being detectable ... | 1977 | 929628 |
| the dose-dependence of sister chromatid exchanges induced by 3 hydrocarbons, in the in vivo bone marrow test with chinese hamsters. | 1977 | 401744 | |
| discrete electrophoretic products of mitochondrial protein synthesis in the chinese hamster ovary cell line. | mitochondrial proteins labelled with [35s]methionine for 1 h in whole chinese hamster ovary (cho) cells in the presence of cycloheximide or emetine, known inhibitors of cytosolic protein synthesis, have been enumerated and characterized by their electrophoretic mobility in sodium dodecyl sulfate slab gel electrophoresis. ten distinct electrophoretic bands were observed. the components were relatively stable during a 2 h postlabelling period. the same 10 bands were also seen with the cho cell lin ... | 1977 | 912598 |
| sensitivity of different cell lines and of different phases in the cell cycle to hyperthermia. | the sensitivity of different cell lines (chinese hamster ovary, hela, l1210, and p388) to 43 degrees was compared chinese hamster ovary and hela cells were much less temperature sensitive than were l1210 or p388 cells. this difference persisted even when hela and l1210 cells were grown in the same medium and suggested that this was an inherent difference between the cell lines. of all the cell lines, 7-day l1210 ascites, maintained by transfer in mice, were the most sensitive. the greater sensit ... | 1977 | 561655 |
| nucleolar chromatin in chinese hamster ovary cells. topographical distribution of ribosomal dna sequences and isolation of ribosomal transcription complexes. | 1977 | 913418 | |
| spontaneous lesions in chinese hamsters. | one hundred and fifty-seven chinese hamsters (cricetulus griseus) from the lovelace foundation inhalation toxicology research institute colony had pulmonary granulomas, nodular hyperplasia of the liver, granulocytic bone marrow hyperplasias and myelogenous leukemia, nephrosclerosis and uterine adenocarcinomas. these chinese hamsters had a median life span of 1 075 days. the long life span and information on naturally-occurring diseases suggest that this species might be more widely used for toxi ... | 1977 | 919235 |
| quantitative analysis of biological marker synthesis in tumor cell cycle. | a quantitative relationship between tumor cell number and biologic marker concentration has been investigated and characterized by the previously developed discrete-time kinetic model for the study of cell kinetics. here, this model is further expanded to cope with both cell cycle kinetics and biologic marker synthesis. a synchronized tumor-cell population is examined to determine the time course of the synthesis of markers in relation to cell cycle. the dna content distributions, measured by fl ... | 1977 | 872404 |
| effects of mercuric chloride on synchronized chinese hamster ovary cells: survival and dna replication. | chinese hamster ovary (cho) cells in vitro were treated with hgcl2 at various stages in the cell cycle and the effects of this chemical on cell survival, dna replication, and cell division were observed. in terms of survival the early g1 cells were the most sensitive to treatment, followed by late g1 and early s, while mid s and late s-g2 treated cells were the least sensitive. treatment with hgcl2 also resulted in reduced rates of dna replication and delays in cell division. the early g1 treate ... | 1977 | 560920 |
| the response of chinese hamster ovary cells to fast-neutron radiotherapy beams. ii. sublethal and potentially lethal damage recovery capabilities. | 1977 | 408868 | |
| repair of the sublethal and mutational damage induced by x-rays in chinese hamster hai cells in vitro. | the ability of chinese hamster hai cells to repair damage related to cell death and mutational change induced by x-rays were examined by using a sensitive forward mutation system from prototrophic ch-hai cl 23 cells to auxotrophs. the results obtained from the split dose experiments seem to suggest that chinese hamster hai cells have the repair mechanisms for the sublethal and mutational damage induced by x-rays and that the repair mechanisms act in common for the repair of both cases of damage. | 1977 | 608187 |
| [replication of chromosomal dna in chinese hamster cells, cultivated at different temperatures]. | dna fiber autoradiography was used to measure the rate of replication and the size of replication units in chinese hamster cells cultured at 34, 37 and 39 degrees c. the average rate of dna replication per single fork is 0.6 mcm/min at 34 degrees and 0.8 mcm/min at 37 and 39 degrees. in contrast to the change in the rate of dna replication, no change was found in the size of replication units, which are more than 200 mcm at 31, 37 and 39 degrees. the change of the length of the s phase at variou ... | 1977 | 563118 |
| clonal growth of chinese hamster cell lines in protein-free media. | a protein-free synthetic medium, mcdb 301, has been developed for clonal growth of chinese hamster ovary cell lines. medium f12 was developed originally for that purpose, but later failed to support good growth without small amounts of serum protein. growth was restored by the addition of nonphysiological amounts of commercially prepared thyroxine or smaller amounts of the trace element selenium. the thyroxine preparation was shown to contain sufficient selenium to account for all of its growth- ... | 1977 | 562838 |
| chromosome loss is responsible for segregation at the hprt locus in chinese hamster cell hybrids. | the phenomenon of segregation of gene expression has been examined in intraspecific somatic cell hybrids. specifically, segregation at the hypoxanthine guanine phosphoribosyltransferase (hprt) locus has been studied in hybrids of chinese hamster cell lines. the role of chromosome segregation, or other chromosomal events has been assessed by detailed comparison of karyotypes in the 6-thioguanine resistant segregants with those of the parental hybrid lines. the results clearly demonstrate that los ... | 1977 | 562539 |
| induction of thioguanine- and ouabain-resistant mutants and single-strand breaks in the dna of chinese hamster ovary cells by 3h-thymidine. | cultured chinese hamster cells were labeled with 6-3h-thymidine or 5-methyl-3h-thymidine and allowed to accumulate damage from 3h decays for various periods of time while frozen. the frequencies of cells resistant to 6-thioguanine or ouabain and the amount of dna damage (i.e., number of single-strand breaks) were determined and compared with the mutation frequencies resulting from x and ultraviolet light irradiation. whereas 3h decays and x rays made only 6-thioguanine-resistant mutants, ultravi ... | 1977 | 914028 |
| somatostatin in the pancreas, stomach and hypothalamus of the diabetic chinese hamster. | 1977 | 908469 | |
| abnormalities in pelvic visceral nerves. a basis for neurogenic bladder in the diabetic chinese hamster. | in order to determine whether bladder dysfunction and hydronephrosis in diabetic chinese hamsters are associated with nerve pathology, the pelvic visceral nerves of diabetic and normal hamsters were examined with histochemical and electron microscopic techniques. acetylcholinesterase activity was reduced in the nerves and on smooth muscle fibers in the urinary bladder of diabetic hamsters when compared to controls. depression of enzyme staining was most marked in those hamsters with the most sev ... | 1977 | 903213 |
| repair of potentially lethal damage in chinese hamster cells after x and alpha irradiation. | 1977 | 897087 | |
| distribution of uv-induced unscheduled dna synthesis in metaphase chromosomes of chinese hamster cells. | 1977 | 891651 | |
| repair following combined x-ray and heat at 41 degrees in plateau-phase mammalian cells. | plateau-phase v79 chinese hamster cells maintained at 37 degrees following x-irradiation demonstrated both sublethal damage repair and potentially lethal damage repair. when cells were kept at 41 degrees for 1 hr following irradiation, no sublethal damage repair was seen. in contrast, irradiated cells maintained at 41 degrees for 1 hr and then returned to 37 degrees were capable of repairing both sublethal and potentially lethal radiation damage; hyperthermic (41 degrees) inhibition of radiation ... | 1977 | 884682 |
| transfer of codominant markers by isolated metaphase chromosomes in chinese hamster ovary cells. | codominant mutations to methotrexate and ouabain resistance in chinese hamster ovary cells can be transferred to recipient chinese hamster ovary cells by isolated metaphase chromosomes. for methotrexate, both the structural change and the increased activity of dihydrofolate reductase (5,6,7,8-tetrahydrofolate:nadp+ oxidoreductase ec 1.5.1.3), characteristic of the donor cells, are observed in the transferents (cells that carry and express functions derived by chromosome transfer). the transferen ... | 1977 | 269408 |
| adhesion of phospholipid vesicles to chinese hamster fibroblasts. role of cell surface proteins. | the adhesion of artificially generated lipid membrane vesicles to chinese hamster v79 fibroblasts in suspension was used as a model system for studying membrane interactions. below their gel-liquid crystalline phase transition temperature, vesicles comprised of dipalmitoyl lecithin (dpl) or dimyristoyl lecithin (dml) absorbed to the surfaces of edta- dissociated cells. these adherent vesicles could not be removed by repeated washings of the treated cells but could be released into the medium by ... | 1977 | 407233 |
| action of heparin on mammalian nuclei. i. differential extraction of histone h1 and cooperative removal of histones from chromatin. | heparin interacts strongly with the histone component of chromatin, forming heparin-histone complexes which resist dissociation by 0.2 m h2so4. heparin treatment of unfractionated histones isolated from nuclei of chinese hamster cells indicates that the affinities of the histone classes for heparin appear in the order from greatest to least: (h3, h4) greater than (h2a, h2b) greater than h1. however, when isolated nuclei are treated with heparin, h1 is released from the chromatin more readily tha ... | 1977 | 884118 |
| dna replication kinetics in x-irradiated chinese hamster ovary cells. | 1977 | 897075 | |
| a radioprotective effect of vitamin c observed in chinese hamster ovary cells. | vitamin c at high concentrations was found to inhibit the growth of cho clone a cells in culture. it had a radioprotective effect, giving a maximum increase in cell survival of a factor of seven under the experimental conditions used. the protective effect was mainly but not exclusively attributable to an increase in the do, the maximum increase observed being the order of 1.4. | 1977 | 890235 |
| no mutagenic effect of enflurane on cultured cells. | enflurane was tested by the 8-azaguanine system for any evidence of mutagenic effects. no significant increase in the number of mutant colonies compared with controls was found after 24 h of exposure of chinese hamster cells to 1.5-6.5% enflurane and no damaged chromosomes were seen in metaphase cells on slides. studies of inhibition of growth rate by enflurane show that in this respect its effects were similar in magnitude to other commonly used inhalation anaesthetic agents, but with regard to ... | 1977 | 889666 |