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time and cell systems as variables in fusion experiments with polyethylene glycol.cell hybridization was done between a monolayer of b14-150 chinese hamster cells and a suspension of either mouse leukemia cells or normal human lymphocytes. cell contact was obtained by centrifugation of the suspension cells onto the monolayer cells in a culture plate. cell fusion was done by means of polyethylene glycol (peg). the optimum time for peg exposure as well as the yield of hybrid cells differed markedly with the different combinations.1978566713
properties of the thymidine transport system of chinese hamster ovary cells as probed by nitrobenzylthioinosine.the transport of thymidine into chinese hamster ovary cells grown in suspension culture was measured under conditions in which thymidine was not metabolized, namely, when cells had been depleted of atp. the system transporting thymidine was saturable (kztm = 70 micron), rapid 50% of transmembrane equilibrium level attained within 8 sec), and was apparently shared by other nucleosides, but not thymine or hypoxanthine. 6([4-nitrobenzyl]thio)-9-beta-d-ribofuranosylpurine, "nitrobenzylthioinosine", ...1978568178
assignment of the gene for glyoxylase i to mouse chromosome 17 by somatic cell genetics.evidence is presented for the assignment of the gene for glyoxylase i to mouse chromosome 17 using mouse x chinese hamster somatic cell hybrids. glo i was not expressed concordantly with any known marker enzymes which represented 11 linkage groups. the presence of chromosome 17 and expression of glo i were concordant in 31/31 clones. glo i is thus linked to the h-2 histocompatibility locus in the mouse.1978569476
replicon sizes in mammalian cells as estimated by an x-ray plus bromodeoxyuridine photolysis method.a new method is described for estimating replicon sizes in mammalian cells. cultures were pulse labeled with [3h]thymidine ([3h]tdr) and bromodeoxyuridine (brdurd) for up to 1 h. the lengths of the resulting labeled regions of dna, lobs, were estimated by a technique wherein the change in molecular weight of nascent dna strands, induced by 313 nm light, is measured by velocity sedimentation in alkaline sucrose gradients. if cells are exposed to 1,000 rads of x-rays immediately before pulse label ...1978570067
[interaction of lambda bacteriophages with mammalian cells. ii. elucidation of the role of interacting components].the study of 3h-thymidine labelled bacteriophage lambda c185757 uptake by hela, rh and chinese hamster cell revealed the lack of cells or phage specificity in the phage interaction with cells. the phage uptake is shown to be an active process depending on the cell state. the mechanism of "protective" action of calcium chloride is found to be as follows: the calcium phosphate precipitate formed in phosphate-containing media absorbs the phage, thus increasing its concentration on the cell surface, ...1979572596
cytogenetic characterization of chinese hamster-sheep somatic cell hybrids.the methods used to characterize cytogenetically chinese hamster x sheep somatic cell hybrids have been reported. g and c banding patterns on hybrid metaphases allowed the discrimination between hamster and sheep chromosomes, and in addition to establish the unidirectional loss of sheep chromosomes in hybrid cells.1979575764
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 ...1977578711
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 ...1977578712
cyto-enetic investigations of mammals. comparison of the genetic activity of cytostatics in mammals.mutagenicity tests have been performed with cp, ip and tp. there is an increase of mutagenic activity from tp to ip to cp 8 h after the second intraperitoneal application. this has been confirmed by analysis of bone marrow chromosomes of mice, rats and chinese hamsters. the maximum mutagenic activity of all three cytostatics was found 12 h after the second injection. thereafter the aberration rate induced by cp decreased quickly. the inactivation of ip and tp and the elimination of chromosome ab ...1977578713
mutagenicity studies with praziquantel, a new anthelmintic drug, in mammalian systems.praziquantel, a new anthelmintic drug with antischistosomal and anticestodal properties, was tested in comparison with a placebo control and a 'positive control' with cyclophosphamide in mammalian test system in vivo for potential mutagenic effects. the test systems used and the tested doses of praziquantel were: (1) dominant lethal test on male nmri mice, 12 mating periods of 4 days each, 1 x 1200 mg/kg bw by mouth; (2) dominant lethal test on female nmri mice, treatment during pre-estrus, 1 x ...1978580366
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 ...1977590651
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 ...1977591566
a fluence response study of lethality and mutagenicity of white, black, and blue fluorescent light, sunlamp, and sunlight irradiation in chinese hamster ovary cells.under a set of defined experimental conditions, the fluence response of chinese hamster ovary (cho) cells to various light sources was studied by measuring single-cell survival and mutation to 6-thioguanine (tg) resistance. fluorescent white, black, and blue lights were sightly lethal and mutagenic. sunlamp light was highly lethal and mutagenic, exhibiting these biological effects within 15 sec of exposure under conditions recommended by the manufacturer for human use. lethal and mutagenic effec ...1977593289
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 ...1977601677
mutagenicity to mammalian cells in culture by (+) and (-) trans-7,8-dihydroxy-7,8-dihydrobenzo(a)pyrenes and the hydrolysis and reduction products of two stereoisomeric benzo(a)pyrene 7,8-diol-9,10-epoxides.the mutagenicity for mammalian cells of benzo(a)pyrene (bp) and 9 of its derivatives was tested by resistance to ouabain in chinese hamster v78 cells. the derivatives included the (-) and (+) enantiomers of trans-7,8-diol; the racemic (+/-)trans-7,8-diol; two triols, (7/8,9)-triol and (7,9/8)-triol; and four tetrols, (7,10/8,9)-tetrol, (7/8,9,10)-tetrol, (7,9/8,10-triol and (7,9,10/8)-tetrol. since v78 cells do not metabolize polycyclic hydrocarbons, mutagenesis was tested both in the presence a ...1978624112
effect of alkane tumor-promoting agents on chemically induced mutagenesis in cultured v79 chinese hamster cells.linear alkanes of specific chain length between 6 and 16 carbon atoms, an aryl derivative of dodecane, and a phorbol diester were tested in a cell culture system for relative ability to enhance mutagenesis induced by a chemical carcinogen, methylazoxymethanol acetate (mam). mutation frequencies at the ouabain-resistance locus were measured. results indicated an excellent correlation between the relative activities of the above compounds in enhancing mutagenesis in the in vitro culture system and ...1978633409
sister chromatid exchanges and growth inhibition induced by the flame retardant tris(2,3-dipromopropyl) phosphate in chinese hamster cells.the effects of the flame retardant tris(2,3-dibromopropyl) phosphate (tris-bp) on growth, sister chromatid exchanges (sce), and chromosome aberrations of chinese hamster v79 cells cultured either in vitro or in diffusion chambers (dc) implanted into mice were studied. tris-bp caused a dose- and time-dependent reduction of cell growth as measured by colony-forming activities. a significant dose-dependent increase in sce was observed in v79 cells either in the cultures treated with tris-bp or in d ...1978642035
saccharin-induced sister chromatid exchanges in chinese hamster and human cells.since the induction of sister chromatid exchanges in cultured cells has been shown to be the most sensitive mammalian system to detect the effects of mutagenic carcinogens, chinese hamster ovary cells and human lymphocytes were exposed to the sodium saccharin found to induce bladder cancer in rats. both that saccharin and a highly purified extract of it increased the yield of sister chromatid exchanges in both types of cells. the results, which were repeatable and statistically highly significan ...1978644315
chromosome analysis of bone marrow in mammals after treatment with isoniazid.cytogenetic investigations in bone marrow from animals treated with isoniazid (inh) were performed in seven different laboratories according to a standard protocol. the experiments were carried out in the chinese hamster, the mouse, and the rat. in short-term studies inh was administered twice at an interval of 24 h in doses of 5, 25, and 125 mg/kg, and the animals were sacrificed 6, 12, 24, and 48 h after the second dose. in long-term studies doses of 25 and 125 mg/kg were administered thrice w ...1978649162
the effect of isoniazid (inh) on chinese hamster and mouse spermatogonia.acute and chronic treatment of chinese hamsters and mice with 5, 25 and 125 mg/kg isoniazid (inh) given by oral intubation did not enhance the chromosomal aberration frequencies in spermatogonia. the structural and numerical aberration rates remained in the range of spontaneous events even after the chronic treatment over 12 weeks with 3 x 125 mg/kg inh per week. this dose is much higher than normally used for prevention and therapy in man (3--16 mg/kg).1978649167
nucleus anomaly test in chinese hamster and in rat after treatment with isoniazid.nucleus anomaly test in chinese hamsters and in rats treated with isoniazid (inh) was carried out according to a standard protocol in two different laboratories. these comprised both short-term studies, in which the tests were performed on animals killed 6, 12, 24, 36, or 48 h after the second of two consecutive doses of 5, 25, or 125 mg/kg inh given at an interval of 24 h, and long-term studies in animals treated with 25 mg/kg inh thrice weekly for 12 weeks. as a rule, each group consisted of a ...1978649174
inhibition of post-replication repair by isonicotinic acid hydrazide.in the presence of the alkylating mutagen n-methyl-n-nitrosourea (mnu), the well-known tuberculostatic ionicotinic acid hydrazide (inh), even in otherwise ineffective doses, depressed cell number and mitotic index in peripheral human lymphocytes and inhibited the post-replication repair process in chinese hamster cells (cho). inh had no influence on unscheduled dna synthesis (cut-and-patch repair), which was negligible in cho cells under our conditions.1978651939
correlation between characteristics of transformation and malignancy of intra and interspecific somatic hybrid cells.the transformed properties of five hybrid cell lines which had either one or another parent in common were studied and compared with their tumorigenicity. three hybrid cell lines, derived from the chinese hamster dc-3f/adx/aza line, were resistant to actinomycin-d. this property seemed to be correlated with the presence of a marker chromosome from the common parent. the tumorigenicity was intermediate between those of the parent cell lines. on the other hand, agglutinability by concanavalin a (c ...1978652265
[effect of various substances on cultured mammalian cell growth].the effect of different home industry materials on the growth of chinese hamster cells in culture has been studied. the plating efficiency of the culture and the ability to produce a monolayer were used as criteria. the materials under study can be divided into three groups: indifferent materials, those partially inhibiting the cell growth, and destructive ones. while constructing the apparatus for cultivation, the following materials are to chosen: titanium, molybdenum glass, plexiglass, polyca ...1978653819
the relationship between transformation and somatic mutation in human and chinese hamster cells.the frequencies of transformations of primary human and chinese hamster fibroblasts have been compared with the spontaneous and induced frequencies of mutation for resistance to thioguanine and ouabain, and for ability to use fructose, using the carcinogens benzo (alpha) pyrene and urethane. whereas the rates and frequencies of mutation were similar in the two cell systems, transformations to morphologically altered cells was observed only in hamster cells. the frequency of this latter transform ...1978657270
membranolytic activity of detergents as studied with cell viability tests.the membranolytic activity of 12 chosen detergents upon ehrlich ascites tumour and chinese hamster lung cells were studied with the fluorescein diacetate and the dye exclusion tests of cell viability. it was found that all these tests give reproducible and concordant results when non-ionic detergents are used but for ionic detergents only the fluorescein diacetate test can be applied. membranolytic activity of the detergents appeared to be uncorrelated with their capacity of membrane solubilizat ...1978658833
colchicine-like effect of diethylstilbestrol (des) on mammalian cells in vitro.diethylstilbestrol (des), a synthetic estrogen, showed colchicine-like effects in vitro on cells of the cell lines such as chinese hamster fibroblast of thymus origin (cht), rat liver (dl), rat erythroblastic leukemia (eden-1/tc) and hela-s3. metaphase arrest was induced 3 h after treatment with 15 microgram/ml of des and polyploid or polynucleated cells were prominently observed more than 24 h after treatment. the arrest, however, was reversible when the agent was removed from the medium. tetra ...1978661838
repair of alkylated dna in chinese hamster cells measured by loss of enzyme-sensitive sites in isolated dna. 1978666813
altered growth properties of chinese hamster cells exposed to 1-methylguanine and 7-methylguanine.primary chinese hamster embryo cell cultures generally yield cell lines with a finite lifetime in culture. however, if early-passage cells are exposed chronically to either of two normal degradation products of transfer rna, 1-methylguanine or 7-methylguanine, they are converted to continuous lines with altered growth characteristics and morphology. the continuous cell lines have saturation densities 2- to 10-fold higher than did finite control cultures, and some have the ability to grow in soft ...1978667823
assignment of nadh-cytochrome b5 reductase (dia1 locus) to human chromosome 22.nadh-cytochrome b5 reductase (dia1, ec. 1.6.2.2) from human fibroblasts and from chinese hamster cells, both identified by immunologic studies, were clearly distinguished after polyacrylamide gel isoelectro-focusing followed by staining for nadh diaphorase activity. in thirteen independent man-hamster hybrids, the human enzyme dia1 presented a positive correlation with the human chromosome g22. eight hybrids were dia1(+) g22(+) and five hybrids were dia1(-) g22(-). these data agree with the rece ...1978669708
dna single-strand lesions due to 'sunlight' and uv light: a comparison of their induction in chinese hamster and human cells, and their fate in chinese hamster cells. 1978674395
structure of the altered oligosaccharide present in glycoproteins from a clone of chinese hamster ovary cells deficient in n-acetylglucosaminyltransferase activity.clone 15b cells, derived from chinese hamster ovary cells and deficient in a specific udp-n-acetylglucosamine:glycoprotein n-acetylglucosaminyltransferase activity, synthesize glycoproteins with altered oligosaccharide units. glycopeptides prepared from these glycoproteins contain large quantities of a glycopeptide with the composition (man)5(glcnac)2-asn whereas parent cells have only small amounts of this glycopeptide. the structure of the glycopeptide was determined by the combination of meth ...1978681360
induced segregation of human syntenic genes by 5-bromodeozyuridine + near-visible light.chromosome-breaking agents have been used in two different procedures for promoting segregation of syntenic genes on human chromosome 12. in method a, a human-chinese hamster cell hybrid containing the single human chromosome 12 was treated either with 5-bromodeoxyuridine brdu + near-visible light or with x-rays. in method b, normal human fibroblasts were treated with brdu + near-visible light followed by their fusion with a chinese hamster glycine-requiring cell mutant cho-k1/gly-a. since the h ...1978684558
ghost-mediated transfer of human hypoxanthine-guanine phosphoribosyl transferase into deficient chinese hamster ovary cells by means of polyethylene glycol-induced fusion. 1978689099
assignment of peptidase s (peps) to chromosome 4 in man using somatic cell hybrids.a starch gel electrophoretic procedure is described that resolves peptidase s (peps) as well as the peptidases a, b, and c in man-rodent, rodent-rodent, and primate-rodent interspecific somatic cell hybrids. the interspecific peps cell hybrid phenotype can be resolved into a pattern which suggests that peps is composed of five or six identical subunits. results are presented supporting assignment of the peps locus to chromosome 4 in man using man-mouse and man-chinese hamster somatic cell hybrid ...1978689684
hypoxanthine phosphoribosyltransferase from chinese hamster brain and human erythrocytes. 1978692400
genetic analysis of tumorigenesis: i. expression of tumor-forming ability in hamster hybrid cell lines.two new fibroblasts cell lines from a male chinese hamster embryo are described: one tumorigenic in nude mice (chef 16-2) and the other not (chef 18-1). both lines have a stable diploid mode and mean of 22 with 10 pairs of homologous autosomes. the cell lines differ unambiguously in cloning ability in methylcellulose, colony morphology, and tumorigenicity; the expression of these traits was examined in a set of 18-1 x 16-2 hybrid clones. the results show initial suppression of tumorigenicity and ...1978694725
evidence against the existence of real isozymes of hypoxanthine phosphoribosyltransferase.a method for reducing the degree of heterogeneity in the electrophoretic enzyme activity pattern of hypoxanthine phosphoribosyltransferase preparations by incubation with a (magnesium) phosphoribosyl diphosphate substrate is described. hypoxanthine phosphoribosyltransferase was isolated from human erythrocytes and chinese hamster livers. a subunit molecular weight of 26000--27000 as reported by other authors was obtained for both enzymes by gel electrophoresis in the presence of dodecylsulfate. ...1978710424
increased tissue conductance and ion transport in guinea pig ileum after exposure to staphylococcus aureus delta-toxin in vitro.prior studies had shown that staphylococcus aureus delta-toxin was able to inhibit water absorption in guinea pig ileum and to elevate the cyclic amp content of this tissue, but was unable to elicit certain cyclic amp-mediated changes in y-1 adrenal or chinese hamster ovary cells. because water movement passively follows the net movement of electrolytes in the gut, this study investigated the effect of delta-toxin on ion transport in guinea pig ileum maintained in vitro. the transmural potential ...1978711309
growth of infective forms of trypanosoma rhodesiense in vitro, the causative agent of african trypanosomiasis.a new approach to the culture of african trypanosomes led to the growth of the infective forms of the causative agent of human african trypanosomiasis. infective cultures of trypanosoma rhodesiense were initiated and maintained in vitro on chinese hamster lung cells. by changing daily one-third of the hepes-buffered rpmi 1640 medium containing 20 percent fetal bovine serum, the trypanosome numbers increased to 3 x 10(6) to 5 x 10(6) cells per milliliter. after 80 days in vitro at 37 degrees c, t ...1978715441
mutagenicity and carcinogenicity of 8-mop/uva in cell cultures.hgprt-deficient mutants of chinese hamster cells and human skin fibroblasts are selected with 6-thioguanine after treatment with the combination 8-mop and uva. calculation based on this study indicate that 1.7 x 10(-5) mutants will be induced in the epidermis per session of puva therapy. induction of cell-transformation was observed in c3h and 3t3 mouse cells.1978719181
surface functions during mitosis i: phagocytosis, pinocytosis and mobility of surface-bound con a.phagocytosis, pinocytosis and the surface distribution of concanavalin a (cona) have been analyzed during mitosis in several mammalian cell lines. use of the bisbenzimidazole dye, hoechst 33258, for chromosome staining after gentle fixation made possible the rapid identification and correlation of mitotic phase with surface properties. phagocytosis of both opsonized and nonopsonized particles is markedly depressed in mitotic cells of the mouse macrophage cell line j774.1. the uptake of opsonized ...1978719746
aconitase (e.c. 4.2.1.3) mitochondrial locus mapped to human chromosome 22: studies with chinese hamster--human somatic cell hybrids.three separate somatic cell fusions were made between chinese hamster lines and human lymphocytes containing (1) a 3/4 translocation, (2) an x/9 translocation, and (3) a 17/9 translocation. eleven independently derived hybrids showed that only human chromosome 22 was consistently present when human aconm was expressed and absent when human aconm was not expressed. these studies assign a gene for human aconm to chromosome 22, and are consistent with prior gene-mapping results.1978728065
genetic analysis of cell malignancy--evidence from somatic cell genetics.when normal nontumorigenic cells are fused with tumorigenic cells some of the resulting hybrids are nontumorigenic in respect to their ability to grow in immune-deficient nude mice. comparison of the chromosome content of nontumorigenic with tumorigenic hybrids, as well as with the cells of tumors which develop from the latter, reveals that in normal human x tumorigenic chinese hamster hybrid crosses, two specific human chromosomes of the nontumorigenic parental line are very likely responsible ...1978728675
isolation of mutant mammalian cells altered in polyamine transport.chinese hamster ovary and rat myoblast cells resistant to the toxic action of methylglyoxal bis guanylhydrazone (mgbg), an antimitotic agent and inhibitor of polyamine synthesis, have been isolated by single step selection. mutagenesis with ethyl methanesulfonate increases the recovery of the variants at least 30-fold. intracellular accumulation of mgbg is greatly reduced in resistant cells. this property is accompanied by a 99% decrease in the uptake of all three naturally occurring polyamines. ...1978730773
excorporation efficacy with ca-dtpa of 241am and 252cf in the skeleton, liver, and kidney of the rat and syrian and chinese hamsters: lack of correlation with the biological half-times. 1978734050
[electron microscopic study of mammalian somatic cell fusion under the action of polyethylene glycol].an electron microscope study of heterokaryons and synkaryons, obtained after the treatment of suspension of human embryonic fibroblasts and cultured fibroblasts of chinese hamster (clone m151) with polyethylene glycol (pec, m. v. 6000) has shown that in 15 minutes after the administration of peg, the cell agglutination and disappearance of plasma membranes between cells takes place. it is not obvious, however, how per is passing through the cell envelope, but the similar action of pef towards th ...1978734774
assignment of the gene for dipeptidase 2 to mus musculus chromosome 18 by somatic cell hybridization.evidence is presented for the assignment of the gene for dipeptidase 2 to mus musculus chromosome 18 by synteny testing and karyotypic analysis of chinese hamster x mouse somatic cell hybrid clones. dip-2 and chromosome 18 were expressed concordantly in 24/24 clones examined (ten primary clones and 14 secondary clones). synteny testing indicated that dip-2 was not expressed concordantly with the expression of any marker enzymes.1978736882
responses of mammalian metaphase chromosomes to endonuclease digestion.digestion of fixed metaphase chromosomes by endonucleases (micrococcal nuclease and dnase ii) under optimal digestion conditions followed by giemsa staining produces sharp banding patterns identical to g-bands. in 3h-thymidine labeled, synchronized metaphase cells of the chinese hamster (cho line), the band induction is accompanied by the removal of dna. the single strand specific nuclease s1 and dnase i do not produce such banding patterns.1978743903
cytogenetic effects of inhaled ozone.we have repeated as closely as possible the experiments of zelac et al., who observed significantly elevated levels of chromosome aberrations in short-term cultures of peripheral lymphocytes from chinese hamsters that had inhaled ozone. unlike zelac et al., we observed no increase in chromosome-type aberration levels, though a small increase in chromatid-aberration levels similar to that reported for exposed human subjects by merz et al. was seen. no increase in the levels of any chromosomal abe ...1978745619
sister-chromatid exchanges induced in rabbit lymphocytes by 2-aminofluorene and 2-acetylaminofluorene after in vitro and in vivo metabolic activation.because short in vitro treatments of chinese hamster cells with 2-aminofluorene and 2-acetylaminofluorene did not increase sces even in the presence of a metabolic activation system, experiments were carried out with rabbits to see if in vivo activation occurred. rabbits injected with 2-af could activate the compound and a transient dose-dependent increase in sces was found in peripheral lymphocytes cultured at various times after the injection. with 2-aaf, however, the response was more variabl ...1978745622
cellular and molecular studies on globin gene expression.globin gene expression has been studied with the use of a combination of cell and molecular biology techniques. with a somatic cell hybrid between mouse erythroleukemia (mel) and human erythroid cells, human and mouse globin genes can be coexpressed in the same hybrid cell. somatic cell hybridization between mel cells and nonerythroid cells (e.g., human fibroblasts) results in hybrid cells that cannot be induced to produce hemoglobin of any type. molecular hybridization of cellular dna and rna w ...1978748760
assignment of a human galactose-1-phosphate uridylyltransferase gene (galt1) to chromosome 9 in human-chinese hamster somatic cell hybrids. 1978752475
toward the development of a standard reference cholera antitoxin.the need for a reference cholera antitoxin to serve as a standard for the calibration of cholera enterotoxin and toxoid as well as for measurement of the antitoxin response in animals and patients was recognized by the nih cholera advisory committee, niaid, dhew, usa. two cholera antitoxins have been used for several years as provisional references, but neither was considered to embody all of the properties of an ideal standard. accordingly, a lot of cholera antitoxin was prepared by immunizatio ...1978753669
[in vitro effect of asbestos fibers on short-term cultures of human lymphocytes].the endocellular incorporation of asbestos fibres seems to be capable to induce on chinese hamster cell cultures numerical and structural chromosome aberrations. in the present study asbestos fibres have been added at different concentrations to human cultured lymphocytes which have been harvested at 48 and 72 h, respectively. the results do not show significant difference in the distribution of chromatid and chromosome-type aberrations between the control cultures and the cultures treated with ...1978755418
chromosomal imbalance in ovulated oocytes from syrian hamsters (mesocricetus auratus) and chinese hamsters (cricetulus griseus).chromosomes were studied in ovulated oocytes from syrian hamsters (mesocricetus auratus) and chinese hamster (cricetulus griseus) to assess the degree of chromosomal imbalance after first meiotic division of oogenesis. only one hyperploid oocyte among 307 studied was detected in the former, and none in oocytes from the latter species. structural chromosome alterations, single chromatids due to presegregation, and diploid chromosome sets resulting from meiotic blockage were not observed. the horm ...1979761487
structural studies of the major high mannose oligosaccharide units from chinese hamster ovary cell glycoproteins.the major high mannose-type glycopeptides present in chinese hamster ovary cells have the compositions (man)9(glcnac)2-asn, (man)8(glcnac)2-asn, and (man)6(glcnac)2-asn. the structures of these glycopeptides were determined by the combination of methylation analysis, acetolysis, smith periodate degradation, and alpha- and beta-mannosidase digestion. their complete structures are: manalpha1 leads to 2manaalpha1 leads to 6(manalpha1 leads to 2manalpha1 leads to 3)manalpha1 leads to 6(manalpha1 lea ...1979762159
isolation and properties of heat-labile enterotoxin(s) from enterotoxigenic escherichia coli.various techniques have been applied to the detection of skin reactivity associated with heat-labile escherichia coli enterotoxin in fermenter-grown cultures of enterotoxigenic strains in syncase medium and in trypticase soy broth. isolated products that were homogeneous, as determined by disc electrophoresis and sodium dodecyl sulfate gel electrophoresis, differed immunologically and in physicochemical characteristics depending on the strain and medium used, even though the products had similar ...1976768386
animal models of diabetes and obesity, including the pbb/ld mouse.diabetes mellitus occurs in many animals species. however, only a few have been utilized in systematic studies designed to answer unsolved problems associated with the disorder in man such as molecular basis, pathogenesis of the vascular and neural lesions, and the roles of diet, exercise and obesity. among the animal models available, rodents have been studied most thoroughly for a number of reasons: a) short generation time (sexually mature at about 3 mo of age, gestation time 21 days) and lif ...1976770197
inhibition of human lymphoma cell-line colony formation by lymphocytes from patients with lymphoma and cancer hospital employees.inhibition of human lymphoma cell-line colony formation (icf) was induced by peripheral blood lymphocytes (pbl) from patients with lymphoma and apparently healthy cancer hospital personnel. pbl from patients with non-lymphoma neoplasms and from normal blood bank donors did not elicit icf. icf was most marked when pbl were cocultivated for 24 hours in a ratio of 1000:i with target lymphoma cells that had been cultured for 24 hours before exposure. no significant icf was observed when target cells ...1976779948
mutagenicity and cytotoxicity of benzo(a)pyrene arene oxides, phenols, quinones, and dihydrodiols in bacterial and mammalian cells.twenty-nine benzo(a)pyrene derivatives were tested for mutagenic acitivity without metabolic activation in salmonella typhimurium strains ta98, ta100, and ta1538 and in chinese hamster v79 cells. the compounds studied included 4 arene oxides, all 12 isomeric phenols, 5 quinones, and 8 dihydrodiols. benzo(a)pyrene 4,5-oxide was the most mutagenic of the compounds tested in both the bacterial and mammalian systems. the other arene oxides [benzo(a)pyrene 7,8-, 9,10-, and 11,12-oxides] were only wea ...1976788898
mutagenicity and cytotoxicity of benzo(a)pyrene benzo-ring epoxides.four benzo-ring epoxides of the environmental carcinogen benzo(a)pyrene (bp) were tested for mutagenic and cytotoxic activity in 3 strains of salmonella typhimurium (ta1538, ta98, and ta100) and in chinese hamster v79 cells. although very unstable in aqueous solution, 7beta,8alpha-dihydroxy-0beta,10beta-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene (diol epoxide 1), with the 7-hydroxyl group on the same face of the molecule as the epoxide oxygen, was 1.5 to 4 times as mutagenic in the bacterial strain ...1976788899
mutagenicity of industrial compounds: styrene and its possible metabolite styrene oxide.styrene and its presumed metabolite, styrene oxide, were tested for their mutagenic effect on a forward mutation system of yeast and of chinese hamster cells, and on a gene-conversion system of yeast. experiments with liver microsomal preparations and host-mediated assay with yeast were also carried out. styrene oxide was mutagenic in all test systems. styrene was mutagenic only in the host-mediated assay.1976796697
the mutagenicity of benzimidazole and benzimidazole derivatives. vi. cytogenetic effects of benzimidazole derivatives in the bone marrow of the mouse and the chinese hamster.methyl benzimidazole-2-ylcarbamate (mbc) was mutagenic in mice by the micro-nucleus test. other benzimidazole derivatives, with the exception of the parent compound of mbc, benomyl, and the very closely related substance 2-benzimidazolylurea, did not produce micro-nuclei in mouse bone marrow. evidence is presented that mbc acts through inhibition of mitosis and that for this action the carbamoyl group is a necessary but not a sufficient condition. it is also demonstrated that for this particular ...1976796698
sister chromatid exchange as an assay for genetic damage induced by mutagen-carcinogens. ii. in vitro test for compounds requiring metabolic activation.sister chromatid exchanges (sce's) which are easily seen by "harlequin chromosome" techniques can be readily induced in cultured chinese hamster ovary (cho) cells by low concentrations of mutagen-carcinogens that do not require metabolic activation. if the cells are simultaneously treated with cyclophosphamide which does require metabolic activation before it becomes mutagenic, and an activating system consisting of an extract of rat liver containing microsomes (s-9 mix) then numerous sce's are ...1976796721
mutagenicity and metabolism of vinyl chloride and related compounds.the various adverse biological effects of vinyl chloride appear to be dependent upon the metabolic conversion of this compound into chemically reactive metabolites. the metabolism of vinyl chloride in mammals and in man, including the formation of monochloroacetic acid and some identified sulfur conjugates is reviewed. hepatic microsomal mixed function oxidases from rats, mice, and humans were equally effective in transforming vinyl chloride into alkylating agents in vitro. two of the enzyme rea ...1976799962
absence of ultrafast processes of repair of single-strand breaks in mammalian dna.town, smith and kaplan (1972) reported that the yield of dna single-strand breaks (ssb) in e. coli is largely independent of the presence of molecular oxygen during irradiation. they suggested that the oxygen enhancement ratio (o.e.r.) normally observed is due to the presence of an ultrafast repair mechanism acting (in bacterial cells) mainly on anoxically-produced breaks. to determine whether similar mechanisms exist in mammalian cells, we carried out comparable experiments on two cell-lines, o ...1975804459
identification of hamster thymus-derived lymphocytes employing rabbit anti-hamster brain serum.rabbit anti-hamster brain sera prepared from the brains of syrian and chinese hamsters were evaluated for their potential to identify thymus-derived lymphocytes present in these animals. the unabsorbed antisera were cytotoxic in vitro for both homologous and heterologous thymocytes and splenocytes. following absorption with hamster liver and erythrocytes, the antisera remained toxic for thymocytes, but were less toxic for splenocytes. comparative testing of both the rabbit anti-syrian and anti-c ...1975807688
distribution of 2,2(1),4,4(1),5,5(1)-hexachlorobiphenyl in mice and chinese hamsters: dose dependent accumulation in the mouse bronchial mucosa.the distribution of 2,2(1),4,4(1),5,5(1)-hexachlorobiphenyl-14c was studied in mice and chinese hamsters using whole body autoradiography and liquid scintillation counting. the mice exhibited a strong and persistent accumulation of radioactivity in the bronchial mucosa, and this accumulation was not fully developed until about 24 hours after an intravenous injection. the labelled substance passed to the fetuses of pregnant mice and was also concentrated in the fetal bronchi. mice pretreated with ...1975812457
alpha-galactosidase in man-chinese hamster somatic cell hybrids. 1975812566
aging changes in intervertebral discs and spondylosis in chinese hamsters.vertebrae and intervertebral discs of chinese hamsters, a species of rodents that develop spontaneous diabetes, were investigated for age-linked changes and for the occurrence of spondylosis. aging changes in the intervertebral discs were similar in diabetic and nondiabetic animals. the incidence of spondylosis was significantly increased and its onset was accelerated in the diabetic animals. the mechanisms operative in the pathogenesis of the lesions and their relation to the human disease are ...1976819318
evaluation and re-evaluation of genetic radiation hazards in man. ii. the arm number hypothesis and the induction of reciprocal translocations in man.the arm number hypothesis proposed by brewen and collagues in 1973 has been examined in the light of information thus far available from mammalian studies. in experiments with peripheral blood lymphocytes (radiation in vitro), a linear relationship between dicentric yield and the effective chromosome arm number of the species was obtained in the mouse, chinese hamster, goat, sheep, pig, wallaby and man. however, the data are not consistent with such a relationship in several primate species (ma ...1976819823
biochemical evidence of variability in the dna repeat length in the chromatin of higher eukaryotes.biochemical evidence is presented which confirms that the dna repeat length in micrococcal nuclease (spleen endonuclease, nucleate 3'-oligonucleotidohydrolase, ec 3-1-4-7) digests of chinese hamster ovary chromatin is shorter than that of rat liver chromatin [j.l. compton, r. hancock, p. oudet, and p. chambon (1976) eur. j. biochem., in press]. a survey of available cells has shown that the dna repeat length of the chromatin of higher eukaryotes varies widely. a value of 196 base pairs was found ...1976826906
confirmation of the assignment of the locus determining ada to chromosome 20 in man: data on possible synteny of ada and itp in human-chinese hamster somatic cell hybrids. 1976828861
intrachromosomal gene mapping in man: assignment of nucleoside phosphorylase to region 14cen leads to 14q21 by interspecific hybridization of cells with a t(x;14) (p22;q21) translocation.the structural gene for purine-nucleoside phosphorylase (np) has been assigned to a subregion of chromosome 14 by somatic cell hybridization of male and female cells containing the balanced translocation t(x;14) (p22;q21). peripheral lymphocytes were fused to a pseudodiploid hprt-deficient established chinese hamster cell line. 23 primary hybrid clones (10 derived from male and 13 from female cells) were isolated and maintained in hat selective medium. parallel subcultures from generations 16, 2 ...1976829289
interpretative differences in cytogenetic analyses: preliminary results of a collaborative study.in an effort to establish some of the parameters which influence differences in interpretation of chromosome aberrations, we initiated a collaborative study with 26 different laboratories located in the u.s., canada and europe. they include government, private industry, and academic institutions. three species were selected for study which vary in chromosome number and complexity of the karyotype. these were the chinese hamster, human, and african green monkey. each metaphase was preselected and ...1976829598
the effect of adriamycin on cell cycle progression and dna replication in chinese hamster ovary cells.administration of[3h]aflatoxin b2 (2,3-dihydroaflatoxin b1)(afb2) to male rats resulted in levels of hepatic dna- and ribosomal (r)rna-aflatoxin adducts that were about 1% of those for rats given [3h]aflatoxin b1(afb1). the levels of hepatic protein-aflatoxin adducts were 35 to70% as great for afb2-treated as compared to afb1-treated rats...1977830405
chromosome replication in somatic hybrids of mouse and temperature sensitive chinese hamster cells. 1977833213
characterization of beta-d-n-acetylhexosaminidase isoenzymes in man-chinese hamster somatic cell hybrids.a series of man-chinese hamster hybrids were investigated with the use of an anti-chinese hamster hexosaminidase serum, a specific anti-human hex a serum and an anti-human hex b serum. the expression of human hex a was found to be dependent on the presence of hex b. a heteropolymeric molecule is formed independently of hex b, which consists of chinese hamster and specific hex a moieties. it has an electrophoretic mobility nearly identical to hex a. a relationship between the absence and presence ...1977835571
th induction of thioguanine-resistant mutants of chinese hamster cells by gamma-rays.the induction of mutation to purine analogue resistance was assessed in chinese hamster v79-4 cells exposed to gamma-radiation. after irradiation, the cells were grown in non-selective medium for different time intervals before respreading into medium containing 0.5-0.7 mug/ml thioguanine. in some experiments colonies arising in thioguanine-medium were counter-selected in medium containing the glutamine analogue azaserine, which distinguishes mutants with very little activity of the enzyme hypox ...1977840237
liver homogenate-mediated mutagenesis in chinese hamster v79 cells by polycyclic aromatic hydrocarbons and aflatoxins.several chemical carcinogens that require metabolic activation have been examined for their cytotoxic and mutagenic activity in chinese hamster v79 cells. mutagenic activity was measured as the induced frequency of 6-thioguanine-resistant colonies. metabolic activation was provided by the 9000 g supernatant fraction of rat liver plus cofactors. the cytotoxicity and mutagenicity of aflatoxin b1 and b2, benzo(a)pyrene, 3-methylcholanthrene, 7,12-dimethylbenz(a)anthracene, dibenz(a,h)-anthracene, d ...1977840239
single strand breakage and repair in eukaryotic dna as assayed by s1 nuclease.a sensitive new approach for measuring the repair of single strand breaks in dna induced by low doses of gamma irradiation was tested in cultured fibroblasts from chinese hamster lung, human afflicted with ataxia telangiectasia or fanconi's anemia and in normal cells of early and late passages. the assay is based on the increasing rate of strand separation of dna duplexes in alkali for molecules with increasing numbers of single strand scissions. dna strand separation is shown to follow the rela ...1977840643
study on cytological effects of carofur -- a new mutagen.chinese hamster cells (line v-79) and human leukocytes in vitro and mice of the cba strain were treated with carofur (also called nifurprazinum), an antibacterial agent of pharmaceutical importance. at concentrations as low as 20 ppm, the in vitro treatments of cells of chinese hamster and human lymphocytes expressed chromosome aberrations, almost exclusively of deletion type. this effect resembles that of fluorodeoxyuridine but may not necessarily reflect the same basic mechanism involved. when ...1977846486
neutral amino acid transport systems of tissue culture cells.we have studied the interactions among a varied group of neutral amino acids for uptake into two different animal tissue culture cell lines. 3t3 mouse cells and chinese hamster ovary cells were used in these studies. the results showed that the affinities of the amino acids clustered into two groups, one including amino acids such as glycine, alanine, and alpha-aminoisobutyric acid and the other group included amino acids such as leucine and phenylalanine. the specificities and properties of the ...1977853037
synthesis of newcastle disease virus polypeptides in a wheat germ cell-free system.we have isolated 18s rna from cytoplasmic extracts of newcastle disease virus-infected chinese hamster ovary cells and tested its ability to direct protein synthesis in extracts derived from wheat germ. the products of the cell-free reaction directed by this rna contain polypeptides that comigrate with np, m,f, and 47k roteins from virions. in addition, the products contain a polypeptide (67k) that migrates on polyacrylamide gels slightly faster than the hn protein from virions. tryptic peptide ...1977853567
response of extremely hypoxic cells to hyperthermia: survival and oxygen enhancement ratios.chinese hamster v79 cells and mouse emt6 cells were made extremely hypoxic with a chamber technique that relies upon gas exchange rather than respiration-assisted oxygen depletion. cells in these chambers were treated with heat (43degrees c) or heat plus x-irradiation, and colony-forming ability was determined. hyperthermia: (a) kills exponentially growing v79 cells more efficiently than plateau-phase cells; (b) kills euoxic and extremely hypoxic cells equally; and (c) radiosensitizes euoxic and ...1977860045
selective incorporation of l-3,4-dihydroxyphenylalanine by s-91 cloudman melanoma in vitro.the incorporation of precursors of the biopigment melanin into melanotic and amelanotic s-91 cloudman melanoma, mouse fibroblast l-929, and chinese hamster ovary cells was studied. tyrosine did not selectively accumulate in pigmented cells compared to that in nonpigmented control cells. inhibition of protein synthesis with cycloheximide provided an estimate of the partition of tyrosine between protein (95%) and pigment biosynthesis (5%). l-3,4-dihydroxyphenylalanine, a more proximal precursor of ...1977861938
structural repeat units of chinese hamster ovary chromatin. evidence for variations in repeat unit dna size in higher eukaryotes.dna lengths in the structural repeat units of chinese hamster ovary (cho) and chicken erythrocyte chromatin were compared by analyzing the sizes of dna fragments produced after treatment of nuclei with staphylococcal nuclease. the repeat length of cho chromatin (173 +- 4 bp) is about 20 base pairs (bp) smaller than that of chicken erythrocyte chromatin (194 +- 8 bp). repeat lengths of rat liver and calf thymus chromatin were found to be about 10 bp shorter than that of chicken erythrocyte chroma ...1977866190
the units of dna replication in the mammalian chromosomes: evidence for a large size of replication units.the replication of chromosomal dna in human and chinese hamster cell populations has been studied by means of the dna fiber autoradiography. it was found that the rate of dna replication for one fork in human cells varies from 0.2 to 0.9 micron/min, the average being 0.6 micron/min. in the chinese hamster cells the rate dna replication is greater, varying from 0.3 to 1.2 micron/min, the average being 0.8 micron/min. there are no clusters containing a great number of replication units in human an ...1977870295
the metabolic activation of 7-methylbenz(a)anthracene: the induction of malignant transformation and mutation in mammalian cells by non-k-region dihydrodiols.four different dihydrodiols derived from 7-methylbenz(a)anthracene have been tested, together with the parent hydrocarbon, for their ability to induce the in vitro malignant transformation of mouse m2 fibroblasts and mutations in v79 chinese hamster cells. in the transformation tests withe the non-k-region dihydrodiols, the 3,4-diol was the most active dihydrodiol tested and the 8,9-diol was also more active than 7-methylbenz(a)anthracene itself; the 1,2-diol showed only slight activity. the k-r ...1977873646
rapid assays for evaluating the drug sensitivity of tumor cells.assays that assess the ability of cells to incorporate labeled precursors into acid-precipitable material in the presence of adriamycin, daunorubicin, puromycin, vinblastine, melphalan, or methotrexate were investigated as an approach to the detection of resistant cells in human tumor samples. each assay was evaluated with suitable drug-resistant chinese hamster ovary cell lines and normal human fibroblasts to determine whether the assays reflected the drug sensitivity of these lines. moreover, ...1977875055
reverse transformation of chinese hamster ovary cells by a factor produced by vibrio parahaemolyticus. 1977875243
pre-implantation embryos of chinese hamster. i. incidence of karyotype anomalies in 226 control embryos.karyotyes were determined in 226 pre-implantation embryos (4--8-cell stages) of chinese hamster. the study was carried out under controlled natural breeding conditions, without superovulation and with the embryos developing in their mothers. a total of 5.3% karyotypically abnormal embryos were found. over half, 3.1%, were due to ploidy mutations, 5 cases of triploidy and 2 cases of haploidy. only 0.9% genome mutations were present, consisting of one autosomal trisomy and one autosomal monosomy. ...1977876265
l-dopa: selective toxicity for melanoma cells in vitro.in a study of the effect of l-dopa, an intermediate in the biosynthesis of the pigment melanin, on the growth of human and murine melanoma cells a highly selective inhibition of growth was observed for pigmented cell lines (s91a and human melanoma) as compared to the nonpigmented control cells (amelanotic melanoma s91b, mouse fibroblast l929, and chinese hamster ovary). there was a correlation between toxicity and the extent of incorporation of radioactively labeled l-dopa by each line.1977877570
regional chromosomal localization of the human gene for galactose-1-phosphate uridyltransferase.in the progeny of somatic cell hybrids formed by fusion of human lymphocytes and chinese hamster mutant cells, a single human chromosome a2 was selectively retained when grown in appropriate medium. spontaneous breakage of this chromosome in different hybrid subclones led to the assignment of the gene for galactose-1-phosphate uridyltransferase to the centromeric region of this chromosome (2q11 leads to 2q14). this gene is shown to be syntenic to the previously mapped genes for acid phosphatase ...1977885547
synteny between glycinamide ribonucleotide synthetase and superoxide dismutase (soluble).the auxotrophic mutant ade -c derived from chinese hamster ovary cell cho-k1 lacks the enzyme glycinamide ribonucleotide synthetase and requires exogenous supplement of purines for growth. cells from this mutant were fused with normal human lymphocytes, and the resulting hybrids were isolated in purine-deficient medium. a total of 32 primary clones and 49 secondary clones were analyzed for various isozyme markers. cytogenetic analysis with chromosome banding was also performed in some hybrid clo ...1977889603
malignant transformation and mutagenesis in mammalian cells induced by vicinal diol-epoxides derived from benzo(a)pyrene.benzo[a] pyrene and the syn- and anti-isomers of the 7,8-diol 9,10-oxide and of the 9,10-diol 7,8-oxide derived from this hydrocarbon have been tested for their abilities to induce malignant transformation in m2 mouse fibroblasts and mutagenesis in v79 chinese hamster cells. the anti-isomer of the 7,8-diol 9,10-oxide induced more mutations and transformation than did the other three vicinal diol-epoxides. the two 9,10-diol 7,8-oxides were moderately mutagenic but did not induce any transformatio ...1977890685
assignment of the gene for enolase to mouse chromosome 4 using somatic cell hybrids.somatic cell hybrids between mouse peritoneal macrophages (mpm) and human fibrosarcoma cells (ht-1080) or chinese hamster cells (a3) were analyzed by starch-gel electrophoresis for the expression of murine enolase. data obtained indicate that the locus for enolase is on chromosome 4 in the mouse.1977891258
metabolic behaviour of nonhistone chromosomal proteins in proliferating and in resting fibroblasts.the metabolism of nonhistone chromosomal proteins was studied in two lines of cells showing a different degree of contact inhibition: human diploid fibroblasts, which are easily contact-inhibited, and chinese hamster fibroblasts, which had been made to stop proliferating by fasting. by following the 3h414c ratio of [3h]tryptophan-labelled nonhistone chromosomal proteins and [14c]thymidine-labelled dna in chase experiments three main groups of these proteins could be detected with respect to thei ...1977891550
the deposition of 241am and 252cf in the skeleton of chinese hamster, syrian hamster and the rat. 1977893106
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