| human interferon omega 1: isolation of the gene, expression in chinese hamster ovary cells and characterization of the recombinant protein. | a gene encoding human interferon omega-1 (ifn-omega 1) was isolated from a cosmid library, sequenced and expressed in chinese hamster ovary (cho) cells under the control of an sv40-derived promoter/enhancer sequence. culture supernatants of stably transfected cell clones contained biologically active ifn-omega 1 at concentrations up to 10 micrograms/l. amplification of the expression vector containing a dhfr gene under methotrexate selection pressure resulted in yields up to 200 micrograms/l. pr ... | 1991 | 1647209 |
| mapping of silver fox genes: chromosomal localization of the genes for got2, ak1, aldoc, acp1, itpa, pgp, and blvr. | evidence is presented for the chromosome localization of seven silver fox genes by the use of a panel of fox x chinese hamster somatic cell hybrids. ak1, got2, and aldoc are assigned to chromosome vfu2, pgp to chromosome vfu38, blvr to chromosome vfu5, acp1 to chromosome vfu8, and itpa to chromosome vfu14. the genetic map of 29 fox genes is compared with those reported for man and other mammals. the results we obtained support and extend our previous suggestion that the formation of the canidae ... | 1991 | 1647290 |
| extracellular release as the major degradative pathway of the insulin-like growth factor ii/mannose 6-phosphate receptor. | the presence of a soluble, truncated form of the igf-ii/man-6-p receptor in serum has suggested that cleavage from the cell surface may be an initial step in the degradation of this protein (macdonald, r. g., tepper, m. a., clairmont, k. b., perregaux, s. b., and czech, m. p. (1989) j. biol. chem. 264, 3256-3261). in order to test this hypothesis, we pulse-labeled cultured brl-3a rat liver cells with [35s]methionine and [35s]cysteine and measured the fate of labeled receptor at various times aft ... | 1991 | 1648081 |
| cell death induced by topoisomerase inhibitors. role of calcium in mammalian cells. | although the stabilization of topoisomerase ii cleavable complexes by etoposide (vp-16) has been recognized to be important for cell killing, the lethal events following the formation of cleavable complexes remain to be elucidated. in an attempt to characterize the biochemical requirements for vp-16-induced cytotoxicity, we examined the effects of calcium depletion in chinese hamster dc3f cells. four-hour preincubation in calcium-free medium or in complete medium containing 5 mm [ethylenebis(oxy ... | 1991 | 1648924 |
| a transduction pathway associated with receptors coupled to the inhibitory guanine nucleotide binding protein gi that amplifies atp-mediated arachidonic acid release. | atp is copackaged and coreleased with adrenergic, serotonergic, and cholinergic neurotransmitters, suggesting a possible interaction between the signaling pathways for atp and these coreleased neurotransmitters. muscarinic m2 and m4, alpha 2-adrenergic, and d2-dopaminergic neurotransmitter receptors, which have in common their ability to inhibit adenylate cyclase through the inhibitory guanine nucleotide binding protein gi, were transfected and expressed in chinese hamster ovary (cho) cells that ... | 1991 | 1650470 |
| measurement of bioreduction rates of cells with distinct responses to ionizing radiation and cisplatin. | a low frequency electron paramagnetic resonance (epr) spectrometer has been used to measure the bioreduction rate of an exogenously added nitroxide free radical species. measurements have been made in a well controlled, in vitro system using an x-ray and cisplatin sensitive chinese hamster ovary (cho) cell line, xrs-5, and partial revertants which display wild-type levels of sensitivity to x-rays but retain xrs-5 levels of cisplatin sensitivity. the xrs-5 cells reduce this radical species at a r ... | 1991 | 1650577 |
| eleven amino acids (lys-201 to lys-211) and 9 amino acids (gly-222 to leu-230) in the human thyrotropin receptor are involved in ligand binding. | our previous studies involving chimeric thyrotropin-lutropin/choriogonadotropin (tsh-lh/cg) receptors suggest that multiple segments spanning the entire extracellular domain of the human tsh receptor contribute to the tsh binding site. nevertheless, the mid-region (segment c, amino acid residues 171-260) of the receptor extracellular domain is particularly important in tsh binding. in the present studies, we constructed seven new chimeric receptors in order to analyze segment c in further detail ... | 1991 | 1651314 |
| [antithrombotic effect of recombinant human thrombomodulin on experimentally induced thrombosis in rats]. | antithrombotic effect of recombinant human thrombomodulin (tm) on experimentally induced thrombosis in mice was studied. the soluble recombinant human tm (tmd 123), which was expressed in chinese hamster ovary cells and purified from the conditioned medium, prolonged thrombin clotting time for mouse plasma in a dose-dependent fashion. thrombosis was induced by the injection of lipopolysaccharide (lps) from e. coli into a lateral tail vein of mice and was identified as disseminated intravascular ... | 1991 | 1651429 |
| evidence for hybrid rodent and human insulin receptors in transfected cells. | chinese hamster ovary cells and nih 3t3 cells overexpressing mutant human insulin receptors were examined for the presence of hybrid receptors composed of human and rodent insulin receptors. in the present studies, most of the endogenous rodent receptors were found to be immunoprecipitated from the transfected cells but not the parental cells with a monoclonal antibody specific for human receptor. these data indicate that in these transfected cells, most of the endogenous rodent receptors are in ... | 1991 | 1651915 |
| functional responses of cloned muscarinic receptors expressed in cho-k1 cells. | the physiological responses to activation of the m5 muscarinic acetylcholine receptor were compared with those of m3 and m4 in transformed chinese hamster ovary cells, using patch-clamp electrophysiological and biochemical techniques. stimulation of the m5 receptor induced increases in both a calcium-dependent potassium conductance and phosphoinositide (pi) metabolism of similar magnitude to those activated by m3. raising of intracellular calcium or injection of inositol-1,4,5-trisphosphate mimi ... | 1991 | 1652053 |
| a 50-kda cytosolic protein complexed with the 90-kda heat shock protein (hsp90) is the same protein complexed with pp60v-src hsp90 in cells transformed by the rous sarcoma virus. | we have previously shown that a 50-kda protein is one component of a heteromeric complex immunoprecipitated by the 90-kda heat shock protein (hsp90) monoclonal antibodies 8d3 and 3g3 (perdew, g. h., and whitelaw, m. l. (1991) j. biol. chem. 266, 6708-6713). in this report, we compare the 50-kda protein with that found in pp60v-src-hsp90-p50 complexes immunoprecipitated from rous sarcoma virus-transformed cells with antibodies to pp60v-src. 35s- and 32p-labeled p50 proteins from each system were ... | 1991 | 1653236 |
| human cytomegalovirus strain towne pp28 gene: sequence comparison to pp28 of hcmv ad169 and stable expression in chinese hamster ovary cells. | human cytomegalovirus (hcmv) contains a 28-kda (pp28) matrix phosphoprotein which has been shown to be highly immunogenic in humans. we have cloned and sequenced the gene encoding pp28 of hcmv towne strain (pp28towne) and have expressed this gene in stable chinese hamster ovary (cho) cell lines in order to examine the structural, functional, and antigenic properties of this protein. the pp28towne gene had 99% nucleotide and 98.4% amino acid similarity to the pp28 gene of hcmv ad169 strain (pp28a ... | 1991 | 1653497 |
| purification and immunological characterization of hplc-purified pertussis toxin subunits. | pertussis toxin (pt), an oligomeric exotoxin of bordetella pertussis containing five dissimilar subunits, is considered to be an essential immunogen in acellular and component pertussis vaccines against whooping cough. a rapid single-step procedure for isolating pt subunits was developed using reverse-phase high-performance liquid chromatography. recoveries of individual subunits were 75% (s1), 70% (s2), greater than 90% (s3), greater than 90% (s4), and 50% (s5), as judged by sds-page and amino ... | 1991 | 1654940 |
| functional properties of two naturally occurring isoforms of the human insulin receptor in chinese hamster ovary cells. | we and others have previously demonstrated that the human insulin receptor messenger rna (mrna) is alternatively spliced such that the 36-nucleotide sequence encoded by exon 11 of the receptor gene is included (ex11+) or excluded (ex11-). although both ex11- and ex11+ insulin receptors which differ in the presence or absence of 12 amino acids in the carboxy-terminal alpha-subunit have been demonstrated to function as insulin receptors when independently overexpressed and studied, the possibility ... | 1991 | 1655392 |
| recombinant 55-kda tumor necrosis factor (tnf) receptor. stoichiometry of binding to tnf alpha and tnf beta and inhibition of tnf activity. | the extracellular domain of the 55-kda tnf receptor (rstnfr beta) has been expressed as a secreted protein in baculovirus-infected insect cells and chinese hamster ovary (cho)/dhfr- cells. a chimeric fusion protein (rstnfr beta-h gamma 3) constructed by inserting the extracellular part of the receptor in front of the hinge region of the human igg c gamma 3 chain has been expressed in mouse myeloma cells. the recombinant receptor proteins were purified from transfected cell culture supernatants b ... | 1991 | 1655744 |
| alpha-thrombin, epidermal growth factor, and okadaic acid activate the na+/h+ exchanger, nhe-1, by phosphorylating a set of common sites. | the ubiquitous and amiloride-sensitive na+/h+ exchanger (nhe-1), a plasma membrane phosphoglycoprotein that regulates intracellular ph, is rapidly activated by growth factors. we showed previously that epidermal growth factor (egf), alpha-thrombin, or serum stimulates na+/h+ exchange activity in growth-arrested chinese hamster lung fibroblasts (er22 cells) in a time-dependent manner which correlates with increased phosphorylation of nhe-1 at serine residues (sardet, c., counillon, l., franchi, a ... | 1991 | 1655777 |
| molecular cloning and expression of the cdna for alpha 3 subunit of human alpha 3 beta 1 (vla-3), an integrin receptor for fibronectin, laminin, and collagen. | alpha 3 beta 1 (vla-3), a member of the integrin family of cell adhesion receptors, may function as a receptor for fibronectin, laminin, and collagen. a partial cdna clone (2.4 kb) for the human alpha 3 subunit was selected from an endothelial cell lambda gt11 cdna library by specific antibody screening. several overlapping cdna clones were subsequently obtained, of a total length of 4.6 kb from various cdna libraries. the reconstructed alpha 3 cdna was expressed on the surface of chinese hamste ... | 1991 | 1655803 |
| localization of the amphotropic murine leukemia virus receptor gene to the pericentromeric region of human chromosome 8. | the host range of retroviruses is determined primarily by the presence of specific receptors on target cells which are recognized by the retroviral envelope glycoprotein. somatic cell hybrids have been used to determine the chromosomal locations of several retroviral receptors in mice prior to their molecular cloning. here we report that by using human-chinese hamster somatic cell hybrids and a retroviral vector, we have mapped the receptor for the amphotropic murine leukemia virus to the perice ... | 1991 | 1656098 |
| mutations in the juxtamembrane region of the insulin receptor impair activation of phosphatidylinositol 3-kinase by insulin. | cho/irf960/t962 cells express a mutant human insulin receptor in which tyr960 and ser962 in the juxtamembrane region of the receptor's beta-subunit are replaced by phe and thr, respectively. the mutant insulin receptor undergoes autophosphorylation normally in response to insulin; however, insulin fails to stimulate thymidine incorporation into dna, glycogen synthesis, and tyrosyl phosphorylation of an endogenous substrate pp185 in these cells. another putative substrate of the insulin receptor ... | 1991 | 1656240 |
| do.oh scavenger secondary radicals protect by competing with oxygen for cellular target sites? | recently, using chinese hamster v79 cells, we found no relationship between the level of protection and the overall rate for .oh removal [ewing and walton, radiat. res. 126, 187-197 (1991)]. we offered several possible interpretations for this observation, including that the scavengers may actually have multiple ways to protect, ways that would occur in addition to, or instead of, simple .oh removal. with bacterial spores, we had noted that protection occurs only with those .oh scavengers that a ... | 1991 | 1656481 |
| functional modulation of brain sodium channels by protein kinase c phosphorylation. | voltage-gated sodium channels, which are responsible for the generation of action potentials in the brain, are phosphorylated by protein kinase c (pkc) in purified form. activation of pkc decreases peak sodium current up to 80 percent and slows its inactivation for sodium channels in rat brain neurons and for rat brain type iia sodium channel alpha subunits heterologously expressed in chinese hamster ovary cells. these effects are specific for pkc because they can be blocked by specific peptide ... | 1991 | 1656525 |
| spectral and enzymatic properties of human recombinant myeloperoxidase: comparison with the mature enzyme. | human recombinant myeloperoxidase (recmpo), purified from an engineered chinese hamster ovary (cho) cell line, has been characterized and compared to the mature enzyme isolated from polymorphonuclear leukocytes. both molecules appear essentially similar in physicochemical enzymatic terms according to the following observations. 1. the unprocessed recombinant protein displays the characteristic light absorption spectra of ferric mature mpo and exhibits its typical spectral changes in the presence ... | 1991 | 1656885 |
| transfection and expression of human o6-methylguanine-dna methyltransferase (mgmt) cdna in chinese hamster cells: the role of mgmt in protection against the genotoxic effects of alkylating agents. | o6-methylguanine-dna methyltransferase (mgmt) is responsible for removal of o6-alkylguanine from dna induced by alkylating mutagens/carcinogens. to analyze the involvement of o6-alkylguanine in the generation and mgmt in avoidance of various genotoxic effects of alkylating agents, we transfected chinese hamster ovary (cho) cells that lack mgmt activity with human mgmt cdna cloned into a mammalian expression vector (psv2mgmt). a high proportion (60-80%) of transfectants selected for a cotransfect ... | 1991 | 1657427 |
| the role of insulin receptor autophosphorylation in signal transduction. | we have examined the role of autophosphorylation in insulin signal transmission by oligonucleotide directed mutagenesis of seven potential tyrosine autophosphorylation sites in the human insulin receptor. chinese hamster ovary cells transfected with these receptors were analyzed for insulin stimulated 2-deoxyglucose uptake, thymidine incorporation, endogenous substrate phosphorylation, and in vitro kinase activity. we found that phosphorylation on tyrosine residues 953, 1316, and 1322 were not n ... | 1991 | 1658004 |
| two dominant inhibitory mutants of p21ras interfere with insulin-induced gene expression. | insulin induces a rapid activation of p21ras in nih 3t3 and chinese hamster ovary cells that overexpress the insulin receptor. previously, we suggested that p21ras may mediate insulin-induced gene expression. to test such a function of p21ras more directly, we studied the effect of different dominant inhibitory mutants of p21ras on the induction of gene expression in response to insulin. we transfected a collagenase promoter-chloramphenicol acetyltransferase (cat) gene or a fos promoter-lucifera ... | 1991 | 1658621 |
| mutation induction by okadaic acid, a protein phosphatase inhibitor, in chl cells, but not in s. typhimurium. | okadaic acid (oa) is a specific and strong inhibitor of protein phosphatases 1 and 2a present in eukaryotes, and a potent promoter of carcinogenesis in mouse skin. in this study, we examined the mutagenicity of oa. oa did not induce mutations in s. typhimurium ta100 and ta98, with or without a microsomal metabolic activation system. however, it was strongly mutagenic to chinese hamster lung (chl) cells without a microsomal activation system, as shown using diphtheria toxin (dt) resistance (dtr) ... | 1991 | 1658641 |
| mechanisms of hypoxic and aerobic cytotoxicity of mitomycin c in chinese hamster v79 cells. | mitomycin c (mmc) induced aerobic and hypoxic cytotoxicity in chinese hamster v79 cells was studied to evaluate the role of the 1-electron versus 2-electron reductive bioactivation. superoxide dismutase, catalase, and desferal had no protective effects on the aerobic or hypoxic cytotoxicity of mmc, whereas tempol and tempol-h, which are known to interrupt and terminate radical reactions, provided partial protection under aerobic conditions. however, under hypoxic conditions, tempol provided comp ... | 1991 | 1660344 |
| a novel glycosylation phenotype expressed by lec23, a chinese hamster ovary mutant deficient in alpha-glucosidase i. | lec23 chinese hamster ovary (cho) cells have been shown to possess a unique lectin resistance phenotype and genotype compared with previously isolated cho glycosylation mutants (stanley, p., sallustio, s., krag, s. s., and dunn, b. (1990) somatic cell mol. genet. 16, 211-223). in this paper, a biochemical basis for the lec23 mutation is identified. the carbohydrates associated with the g glycoprotein of vesicular stomatitis virus (vsv) grown in lec23 cells (lec23/vsv) were found to possess predo ... | 1991 | 1660460 |
| extracellular domain-igg fusion proteins for three human natriuretic peptide receptors. hormone pharmacology and application to solid phase screening of synthetic peptide antisera. | the natriuretic peptide receptors (nprs) are a family of three cell surface glycoproteins, each with a single transmembrane domain. two of these receptors, designated npr-a and npr-b, are membrane guanylyl cyclases that synthesize cgmp in response to hormone stimulation. the third receptor, npr-c, has been reported to function in the metabolic clearance of ligand and in guanylyl cyclase-independent signal transduction. we engineered three chimeric proteins consisting of the natriuretic peptide r ... | 1991 | 1660465 |
| a tumor necrosis factor (tnf) receptor-igg heavy chain chimeric protein as a bivalent antagonist of tnf activity. | using a multistep polymerase chain reaction method, we have produced a construct in which a cdna sequence encoding the extracellular domain of the human 55-kd tumor necrosis factor (tnf) receptor is attached to a sequence encoding the fc portion and hinge region of a mouse igg1 heavy chain through an oligomer encoding a thrombin-sensitive peptide linker. this construct was placed downstream from a cytomegalovirus promoter sequence, and expressed in chinese hamster ovary cells. a secreted protein ... | 1991 | 1660525 |
| efficient selection for high-expression transfectants with a novel eukaryotic vector. | we have developed a new expression vector which allows efficient selection for transfectants that express foreign genes at high levels. the vector is composed of a ubiquitously strong promoter based on the beta-actin promoter, a 69% subregion of the bovine papilloma virus genome, and a mutant neomycin phosphotransferase ii-encoding gene driven by a weak promoter, which confers only marginal resistance to g418. thus, high concentrations of g418 (approx. 800 micrograms/ml) effectively select for t ... | 1991 | 1660837 |
| similarities and differences in the function of regulatory elements at the 5' end of the human apolipoprotein b gene in cultured hepatoma (hepg2) and colon carcinoma (caco-2) cells. | the arrangement of regulatory elements along the apolipoprotein b promoter region (positions -898 to +1) has been examined in transient transfection experiments performed in hepg2 and hep3b (hepatic) and caco-2 (intestinal) cell lines, all of which express the apob gene, and also in chinese hamster ovary cells, which do not express the gene. the overall distribution of positive and negative regulatory segments was very similar in the two hepatoma cell lines (hepg2 and hep3b) but different from t ... | 1991 | 1660892 |
| analysis of the chinese hamster p-glycoprotein/multidrug resistance gene pgp1 reveals that the ap-1 site is essential for full promoter activity. | recent studies have revealed that the expression of p-glycoprotein/multidrug resistance genes is crucial for the development of resistance to a number of lipophilic cancer chemotherapeutic agents. to better understand the regulatory mechanisms of pgp gene expression, we isolated and characterized a dna fragment containing the 5' portion of a chinese hamster pgp gene. dna sequence analysis revealed that this gene is pgp1, the hamster homologue of murine mdr3/mdr1a. this gene is expressed at a hig ... | 1991 | 1661134 |
| the mouse 5-ht1c receptor contains eight hydrophobic domains and is x-linked. | the neurotransmitter serotonin (5-hydroxytryptamine, 5-ht) exerts diverse physiological effects in the central and peripheral nervous systems and in smooth muscle by interacting with pharmacologically distinct membrane receptors. we report here the cdna cloning of the mouse 5-ht1c receptor and its functional expression in xenopus oocytes. this receptor possesses the unusual feature of containing eight hydrophobic domains capable of forming membrane-spanning alpha-helices, contrary to the usual ' ... | 1991 | 1661811 |
| tumor necrosis factor receptor genes, tnfr1 and tnfr2, on human chromosomes 12 and 1. | tumor necrosis factor, tnf, is a 17-kda protein secreted by macrophages and classified as a cytokine. tnf binds to high-affinity receptors on the cell surface and is involved in a wide variety of biological responses. there are at least two types of receptors, tumor necrosis factor receptors 1 and 2 (tnfr1 and tnfr2). the genes for tnfr1 a 55-kda protein, and tnfr2, a 70-kda protein, have been mapped to human chromosomes 1 12 (12pter-cen) and (1pter-p32), respectively, by southern blot analysis ... | 1991 | 1662415 |
| evaluation of endothelin receptor populations using endothelin-1 biotinylated at lysine-9 sidechain. | optimal conditions for biotinylation of endothelin-1 (et-1) were determined using biotinylating reagents of variable linker arm length and mono- vs dual-biotinylated et-1. specific modification of lysine-9 sidechain with nhs-lc-biotin (et-1[btk9]) produced a derivative with maximal binding and retention of vascular smooth muscle contractile activity. the et-1[btk9] probe bound to chinese hamster ovary cells transfected with eta receptor cdna (cho[etr]), but not untransfected cells. binding to ra ... | 1991 | 1662495 |
| radiation hybrid map of 13 loci on the long arm of chromosome 5. | radiation hybrid mapping was used in conjunction with a natural deletion mapping panel to predict the order of and distance between 13 loci in the distal portion of the long arm of human chromosome 5. a panel of irradiation hybrids containing fragments of 5q was generated from an hprt+ chinese hamster-human cell hybrid containing a derivative chromosome 5 [der(5)t(4;5)(5qter----5p15.1::4p15.1----4pter)] as its only human dna. one hundred nine radiation hybrids containing human dna were screened ... | 1991 | 1663488 |
| trichinella pseudospiralis overcomes innate resistance of the chinese hamster to trichinella spiralis. | infectivity of trichinella pseudospiralis in chinese hamsters was greater than that of trichinella spiralis. concurrent infection with these two species of parasite was accompanied by an increase in infectivity of t. spiralis. the infectivity of t. pseudospiralis, but not that of t. spiralis, was significantly influenced by host age. regardless of host age, t. pseudospiralis was more infective for the chinese hamster than was t. spiralis. early during infection, enteritis (myeloperoxidase activi ... | 1991 | 1664077 |
| a brain l-type calcium channel alpha 1 subunit gene (cchl1a2) maps to mouse chromosome 14 and human chromosome 3. | a rat brain cdna probe was used to localize a gene encoding the alpha 1 subunit of neuronal dihydropyridine-sensitive l-type calcium channels in the mouse and human genomes. hybridization of the probe to southern blots made with dnas from a chinese hamster x mouse somatic cell hybrid panel indicated that this gene maps to mouse chromosome 14 (chr 14). southern blot analysis of an intersubspecies cross demonstrated that the calcium channel alpha 1 subunit gene, termed cchl1a2, can be positioned 7 ... | 1991 | 1664412 |
| biological and molecular studies of endogenous retrovirus-like genes in chinese hamster cell lines. | two types of endogenous retroviral-like sequences related to type c or intracisternal a particle (iap) genes respectively were detected in the chinese hamster (ch) genome. their structure and expression were analysed by virological and molecular approaches in different ch cell lines. several clones were isolated from a cho genomic library by screening--in stringent conditions--with type c (gross-mulv) or iap (pmia1) specific probes. these clones were further characterized by restriction mapping ... | 1991 | 1665458 |
| defective endogenous retrovirus-like sequences and particles of chinese hamster ovary cells. | the presence of budding c-type and intracytoplasmic a-type particles in chinese hamster ovary (cho) cells is well documented. however, extensive screening has failed to detect any evidence of infectivity. to investigate the origin and expression of these particles, retrovirus-like sequences which are actively transcribed in cho cells have been cloned and characterized. two families of sequences related to intracisternal a-particle (iap) genomes of mice and syrian hamsters were identified in cyto ... | 1991 | 1665459 |
| recombinant bovine neurokinin-2 receptor stably expressed in chinese hamster ovary cells couples to multiple signal transduction pathways. | neurokinins are a family of neuropeptides with widespread distribution mediating a broad spectrum of physiological actions through three distinct receptor subtypes: nk-1, nk-2, and nk-3. we investigated some of the second messenger and cellular processes under control by the recombinant bovine nk-2 receptor stably expressed in chinese hamster ovary cells. in this system the nk-2 receptor displays its expected pharmacological characteristics, and the physiological agonist neurokinin a stimulates ... | 1991 | 1666301 |
| specific association of an m-phase kinase with isolated mitotic spindles and identification of two of its substrates as map4 and map1b. | isolated mammalian (chinese hamster ovary [cho]) metaphase spindles were found to be enriched in a histone h1 kinase whose activity was mitotic-cycle dependent. two substrates for the kinase were identified as map1b and map4. partially purified spindle kinase retained activity for the spindle microtubule-associated proteins (maps) as well as brain and other tissue culture maps; on phosphorylation, spindle maps exhibited increased immunoreactivity with mpm-2, a monoclonal antibody specific for a ... | 1991 | 1667090 |
| purification and characterization of recombinant human testis angiotensin-converting enzyme expressed in chinese hamster ovary cells. | enzymatically active human testis angiotensin-converting enzyme (ace) was expressed in chinese hamster ovary (cho) cells stably transfected with each of three vectors: p omega-ace contains a full-length testis ace cdna under the control of a retroviral promoter; and plen-acevii and plen-ace6/5, in which full-length and membrane anchor-minus testis ace cdnas, respectively, are under the control of the human metallothionein iia promoter and sv40 enhancer. in every case, active recombinant human te ... | 1991 | 1668266 |
| reparability of dna double-strand breaks and radiation sensitivity in five mammalian cell lines. | we examined the relationship between gamma-ray-induced dna double-strand breaks (dsb) and cell lethality in five mammalian cell lines differing in radiosensitivity; ha-1, hmv-i, l5178y, m10 and lx830. these cells were derived from chinese hamster, human melanoma, and mouse lymphoma (parent and its radiosensitive mutants), respectively. ha-1 cells were the most radioresistant and lx830 cells were the most radiosensitive among these five lines. although the induction of dsb by gamma-rays for ha-1 ... | 1991 | 1671079 |
| isolation and mapping of 62 new rflp markers on human chromosome 11. | to obtain new rflp markers on human chromosome 11 for a high-resolution map, we constructed a cosmid library from a chinese hamster x human somatic hybrid cell line that retains only human chromosome 11 in a chinese hamster genomic background. a total of 3,500 cosmids were isolated by colony hybridization with labeled human genomic dna. dna was prepared from 130 of these cosmid clones and examined for rflp. in 62 of them, polymorphism was detected with one or more enzymes; four rflps were vntr s ... | 1991 | 1671318 |
| reversal of intrinsic multidrug resistance in chinese hamster ovary cells by amiloride analogs. | a number of amiloride analogs can sensitise wild type chinese hamster ovary (cho) cells to the cytotoxic action of vinblastine, daunomycin, puromycin or colchicine. some of these analogs also have weak sensitising effects on the multidrug resistant cho cell line, chrc5. the unusual feature of most of the active amiloride analogs is that they are more potent in reversing the intrinsic multidrug resistance (mdr) phenotype of cho cells than their acquired mdr characteristic. human hela cells that d ... | 1991 | 1671752 |
| isolation and sequence of a cdna encoding mouse imp dehydrogenase. | inosinic acid (imp) dehydrogenase (impd) catalyzes the conversion of imp to xmp as the first committed step in gmp biosynthesis de novo. we have isolated a cdna containing the complete coding region of mouse impd by its ability to complement a bacterial mutant lacking impd activity. two independent cdna clones were isolated by complementation, of which the longest was 1.7 kb in length. northern analyses, using the impd cdna as a probe, indicated that mature impd mrna was a single species approx. ... | 1991 | 1671845 |
| full length and alternatively spliced pgp1 transcripts in multidrug-resistant chinese hamster lung cells. | in an effort to better understand the preferential resistance to actinomycin d displayed by the multidrug-resistant chinese hamster lung cell line dc-3f/adx, we have cloned from those cells a number of cdnas representing p-glycoprotein gene transcripts. of the 12 clones isolated, all represent pgp1 transcripts and one, padx165, contains a 4304-base pair insert with an open reading frame encoding a 1276-amino acid protein that is the homolog of the mouse mdr3/mdr1a gene product. a domain by domai ... | 1991 | 1671863 |
| formation of the n-nitroso derivatives of six beta-adrenergic-blocking agents and their genotoxic effects in rat and human hepatocytes. | six beta-adrenergic-blocking drugs, atenolol, metoprolol, nadolol, oxprenolol, propranolol and sotalol, were found to react with sodium nitrite in hcl solution, yielding the corresponding n-nitrosamines. the genotoxic activity of the six nitrosamines was evaluated in primary cultures of both rat and human hepatocytes; dna fragmentation was measured by the alkaline elution technique, and dna repair synthesis by quantitative autoradiography. positive dose-related responses were produced in cells o ... | 1991 | 1673086 |
| a possible role for a mammalian facilitative hexose transporter in the development of resistance to drugs. | we show that d- but not l-hexoses modulate the accumulation of radioactive vinblastine in injected xenopus laevis oocytes expressing the murine mdr1b p-glycoprotein. we also show that x. laevis oocytes injected with rna encoding the rat erythroid/brain glucose transport protein (glut1) and expressing the corresponding functional transporter exhibit a lower accumulation of [3h]vinblastine and show a greater capacity to extrude the drug than do control oocytes not expressing the rat glut1 protein. ... | 1991 | 1675425 |
| cloning and expression of the human vasoactive intestinal peptide receptor. | vasoactive intestinal peptide (vip) is a neuroendocrine mediator found in the central and peripheral nervous system. distinct subsets of neural, respiratory, gastrointestinal, and immune cells bear specific high-affinity receptors for vip, which are associated with a guanine nucleotide-binding (g) protein capable of activating adenylate cyclase. a cdna clone (gprn1) encoding the human vip receptor was identified in libraries prepared from the nalm 6 line of leukemic pre-b lymphoblasts and the ht ... | 1991 | 1675791 |
| induction of chromosomal aberrations by dnase i. | chinese hamster ovary (cho) cells were treated with bovine pancreatic dnase i using the method of electroporation. the enzyme induced chromosomal aberrations in a s-phase independent manner. the frequencies of polycentric chromosomes induced in the g1 phase of the cell cycle are positively correlated with the dose of dnase i. the distributions of dnase i-induced polycentric chromosomes were overdispersed. | 1991 | 1677382 |
| interaction with functional membrane proteins--a common mechanism of toxicity for lipophilic environmental chemicals? | 1. the effects of several phenols, anilines and aliphatic alcohols on yeast plasma membrane h(+)-atpase and purine transport system as well as on na+, k(+)-atpase and adenosine uptake by chinese hamster ovary cells (cho) were investigated. 2. in all cases an inhibition was observed, which could be correlated with the octanol/water partition coefficients of the substances tested, thus making quantitative structure-activity predictions possible. 3. the observed effects correlated well with the inf ... | 1991 | 1677839 |
| high-level expression of enzymatically active mature human gamma-glutamyltransferase in transgenic v79 chinese hamster cells. | gamma-glutamyltransferase [ggt; (5-glutamyl)-peptide:amino-acid 5-glutamyltransferase, ec 2.3.2.2] is a glutathione-metabolizing enzyme, whose activity variations in serum and organs are valuable markers of preneoplastic processes, alcohol abuse, and induction by xenobiotics. to elucidate the implication of ggt in various metabolic pathways, we established a stable transgenic v79 cell line, highly producing the human ggt. a full-length cdna, encoding the human hepatoma hepg2 ggt, was subcloned i ... | 1991 | 1678521 |
| stable expression of transfected human involucrin gene in various cell types: evidence for in situ cross-linking by type i and type ii transglutaminase. | involucrin is a 68-kd precursor of the cornified envelope in keratinocytes. during terminal differentiation, involucrin becomes covalently cross-linked to other proteins by a membrane-anchored calcium-activated transglutaminase (tg) to form part of the cornified envelope. to better understand this process, we have used vector-mediated gene transfer to express human involucrin in a variety of cell types. authentic involucrin protein was expressed in chinese hamster ovarian (cho) cells (fibroblast ... | 1991 | 1678767 |
| site-directed mutagenesis of alpha 2a-adrenergic receptors: identification of amino acids involved in ligand binding and receptor activation by agonists. | molecular cloning of the alpha 2a-adrenergic receptor has shown that this receptor is a member of the gene superfamily of guanine nucleotide-binding protein (g protein)-coupled receptors. the alpha 2a-adrenergic receptor expressed in chinese hamster ovary (cho) cells attenuates and potentiates forskolin-stimulated camp production through independent signaling pathways. to examine the role of three conserved aspartic acid and two conserved serine residues in alpha 2a-adrenergic receptor function, ... | 1991 | 1678850 |
| human beta 1- and beta 2-adrenergic receptor binding and mediated accumulation of camp in transfected chinese hamster ovary cells. profile of nebivolol and known beta-adrenergic blockers. | the interaction of nebivolol and its srrr and rsss enantiomers, and of known beta-adrenergic blockers, with human beta 1- and beta 2-adrenergic receptors expressed separately in chinese hamster ovary cells in culture (cho-hu beta 1 and cho-hu beta 2), was investigated. we studied [3h]cgp-12177 binding to the intact cells and the accumulation of camp induced by isoproterenol. each of the receptor subtypes displayed saturable [3h]cgp-12177 binding on intact cells with sub-nanomolar affinity. the d ... | 1991 | 1681809 |
| the cap and poly(a) tail function synergistically to regulate mrna translational efficiency. | the cap structure and the poly(a) tail are important regulatory determinants in establishing the translational efficiency of a messenger rna. although the mechanism by which either determinant functions remains poorly characterized, the interaction between the poly(a) tail-poly(a)-binding protein complex and events occurring at the 5' terminus during translation initiation has been an intriguing possibility. in this report, the mutual dependence of the cap and the poly(a) tail was studied. poly( ... | 1991 | 1682219 |
| construction of minitransposons for constitutive and inducible expression of pertussis toxin in bvg-negative bordetella bronchiseptica. | appropriately detoxified pertussis toxin (pt) of bordetella pertussis is considered to be an essential component of new-generation whooping cough vaccines, but the development of a procedure to obtain high levels of purified toxin has been and continues to be a major difficulty. to produce a system enabling the biological separation of pt from other virulence determinants of b. pertussis and the attainment of high yields of the toxin, minitransposons containing the pt operon were constructed and ... | 1991 | 1682257 |
| atypical beta-adrenergic receptor in 3t3-f442a adipocytes. pharmacological and molecular relationship with the human beta 3-adrenergic receptor. | expression of ligand binding properties for an atypical beta-adrenergic receptor (beta-ar) subtype was studied during the adipose differentiation of murine 3t3-f442a cells and compared with that of the human beta 3-ar expressed in chinese hamster ovary cells stably transfected with the human beta 3-ar gene (cho-beta 3 cells) emorine, l. j., marullo, s., briend-sutren, m. m., patey, g., tate, k., delavier-klutchko, c., and strosberg, a. d. (1989) science 245, 1118-1121). 3t3-f442a adipocytes exhi ... | 1991 | 1682311 |
| multidrug resistance gene (mdr1) expression in human brain tumors. | multidrug resistance for many types of cancer outside the central nervous system (cns) has been found to be due to the overexpression of the multidrug resistance gene mdr1, of which the gene-product p-glycoprotein acts as a membrane-bound efflux pump for many anticancer drugs. to examine whether brain tumors overexpress the mdr1 gene, 25 brain-tumor specimens were subjected to northern blot analysis: 10 gliomas, eight meningiomas, three schwannomas, one malignant lymphoma, and three tumors metas ... | 1991 | 1682428 |
| molecular cloning and expression of the rat beta 3-adrenergic receptor. | rat adipose tissues contain atypical beta receptors that display certain pharmacological sensitivities that are similar to those found in the recently cloned human beta 3 receptor. however, there are also certain pharmacological differences between the human atypical beta 3 receptor and atypical receptors in rodent adipose tissues, which could indicate strong species differences, the existence of multiple atypical receptor subtypes, or both. to help decide among these possibilities, a rat beta 3 ... | 1991 | 1684635 |
| molecular biology and transgenetics of prion diseases. | considerable progress has been made deciphering the role of an abnormal isoform of the prion protein (prp) in scrapie of animals and gerstmann-sträussler syndrome (gss) of humans. some transgenic (tg) mouse (mo) lines that carry and express a syrian hamster (ha) prp gene developed scrapie 75 d after inoculation with ha prions; non-tg mice failed to show symptoms after greater than 500 d. brains of these infected tg(haprp) mice featured protease-resistant haprpsc, amyloid plaques characteristic f ... | 1991 | 1684745 |
| application of laser optical tweezers in immunology and molecular genetics. | optical tweezers, based on a compact diode pumped nd:yag laser providing 350 mw at 1,064 nm coupled into a zeiss im 35 microscope, were used to sort cd4+ t cells into a capillary for further mechanical handling and to establish contact between single human natural killer (nk) cells and human erythroleukemia cells (k562) as targets. after contact and a lag phase of a few tens of seconds, the target cell starts to change its morphology and membrane blebbing occurs. the kinetics of the attack of th ... | 1991 | 1684929 |
| complete cdna sequences encoding the chinese hamster p-glycoprotein gene family. | the only function of the transport protein p-glycoprotein (pgp) that has been identified to date in mammals is its ability to mediate multidrug resistance (mdr) in tumour cell lines. rodents have three p-glycoprotein (pgp) genes (termed pgp or mdr 1, 2 and 3), and humans have two (mdr1 and mdr3/mdr2). pgp isoforms differ in their drug transport capabilities: pgp1 and pgp2 can mediate mdr, while pgp3 apparently cannot. the expression of the gene family members is tissue-specific, suggesting that ... | 1991 | 1685679 |
| genotoxicity of vanadium compounds in yeast and cultured mammalian cells. | the ability of vanadium compounds to induce genetic activity was investigated in d7 and d61m strains of saccharomyces cerevisiae and in chinese hamster v79 cell line. in our previous work, ammonium metavanadate (pentavalent form, v5) induced mitotic gene conversion and point reverse mutation in the d7 strain of yeast. the genotoxicity was reduced by the presence of s9 fraction, which probably reduced pentavalent vanadium to the tetravalent form. in the present study, vanadyl sulfate (tetravalent ... | 1991 | 1685805 |
| molecular biology of prions causing infectious and genetic encephalopathies of humans as well as scrapie of sheep and bse of cattle. | considerable progress has been made in deciphering the role of an abnormal isoform of the prion protein (prp) in scrapie of animals and gerstmann-sträussler syndrome (gss) of humans. transgenic (tg) mice expressing both syrian hamster (ha) and mouse (mo) prp genes, which encode proteins differing at 16 residues out of 254, were used to probe the mechanism of scrapie prion replication. four tg lines expressing haprp exhibited distinct incubation times ranging from 48 to 277 days after ha prion in ... | 1991 | 1686599 |
| analysis of rat lymphocyte activation of benzo[a]pyrene, 2-acetylaminofluorene, and several of their metabolites to mutagenic and dna-damaging species in vitro. | rat lymphocytes are a potentially useful and convenient cell system for monitoring the genotoxic effects of chemicals in vivo, but little is known about the ability of these cells to metabolize promutagens to genotoxic species. in this study, fischer 344 rat lymphocytes were treated in vitro with benzo[a]pyrene (bap), 2-acetylaminofluorene (2-aaf), and several of their metabolites, and dna damage was measured using nucleoid sedimentation analysis. of the bap derivatives, bap 4,5-oxide and bap 7, ... | 1991 | 1686675 |
| dopamine d2 receptor binding properties of [3h]u-86170, a dopamine receptor agonist. | u-86170f, an imidazoguinolinone, is a potent dopamine d2 agonist, binding with high affinity to the dopamine d2 receptor. a kd of 0.99 nm was determined in membranes from chinese hamster ovarian (cho) cells transfected with the d2 receptor and a kd of 1.72 nm was obtained in rat striatal homogenates. gtp sensitivity was demonstrated when its addition (300 microm) reduced [3h]u-86170 binding by 60%. this agonist ligand is especially effective in identifying agonists and partial agonists, as well ... | 1991 | 1687034 |
| phosphatidylinositol kinase or an associated protein is a substrate for the insulin receptor tyrosine kinase. | the tyrosine kinase activity intrinsic to the insulin receptor is thought to be important in eliciting the intracellular responses to insulin; however, it has been difficult to determine the biochemical functions of the proteins which are substrates for this receptor. treatment of chinese hamster ovary (cho) cells overexpressing the human insulin receptor (cho.t) with insulin results in a 38 +/- 11 (mean +/- s.e., n = 9)-fold increase in a phosphatidylinositol (ptdins) kinase activity in anti-ph ... | 1990 | 1688432 |
| establishment of specific monoclonal antibodies against recombinant human granulocyte colony-stimulating factor (hg-csf) and their application for immunoperoxidase staining of paraffin-embedded sections. | detection of granulocyte colony-stimulating factor (g-csf), one of the substances responsible for proliferation and differentiation of granulocytes, has been performed up to the present by use of the granulocyte colony-formation assay, because of the lack of a specific anti-g-csf antibody. this has prevented the advancement of biological investigations of cell dynamics linked to g-csf, e.g., cell localization of g-csf and its pathophysiological changes. in the present work, two monoclonal antibo ... | 1990 | 1688901 |
| nucleolus organizer regions in human lymphocytes as studied with premature chromosome condensation. | non-stimulated human lymphocytes from peripheral blood usually contain only one ring-shaped nucleolus. polyethyleneglycol-mediated cell fusion with mitotic chinese hamster ovary cells induces premature chromosome condensation in human lymphocytes. subsequent silver staining reveals that more than one nucleolus organizer region (nor) is silver-positive and frequently participates in the formation of "satellite associations". it can therefore be concluded that more than one nor contributes to the ... | 1990 | 1689268 |
| quantitative in vivo assay of human granulocyte colony-stimulating factor using cyclophosphamide-induced neutropenic mice. | administration of human granulocyte colony-stimulating factor (hg-csf) to mice with cyclophosphamide (cpa)-induced neutropenia for 4 consecutive days from the day after the cpa dosing (100 mg/kg) resulted in a dose-dependent increase in the peripheral blood neutrophil count 6 hours after the final hg-csf injection. within the hg-csf dose range of 0.1 to 10 micrograms per mouse per day, there was a strong linear relationship (r greater than .9) between the logarithm of the dose and the peripheral ... | 1990 | 1690032 |
| effects of sodium arsenite on the cytotoxicity of bleomycin. | our present data show that posttreatment with sodium arsenite has no effect on the cytotoxicity of bleomycin (blm), a radiomimetic agent, in chinese hamster ovary (cho) cells, human skin fibroblasts, and hela cells. however, pretreatment with sodium arsenite potentiated the cytotoxic effects of blm in cho cells. this effect decreased with increasing time interval between the treatments with sodium arsenite and blm. blm-inactivating activity was markedly reduced in cells pretreated with sodium ar ... | 1990 | 1690466 |
| cyclic amp responses are suppressed in mammalian cells expressing the yeast low km camp-phosphodiesterase gene. | a genomic dna fragment from saccharomyces cerevisiae which contains the sra5 (=pde2) gene, coding for a low km camp-phosphodiesterase, was transfected into chinese hamster ovary cells. clones carring the camp-phosphodiesterase gene were capable of growth in the presence of cholera toxin, which slows the growth of untransfected cells by elevating their camp levels. the cholera toxin-resistant transfected cell lines expressed high levels of camp-phosphodiesterase mrna and camp-phosphodiesterase ac ... | 1990 | 1690715 |
| stable expression of rat cytochrome p-450ia1 cdna in v79 chinese hamster cells and their use in mutagenicity testing. | v79 chinese hamster cells genetically engineered to express cytochrome p-450ia1 are reported. a full length cdna encoding rat cytochrome p-450ia1 was obtained from a cdna library prepared from rat liver mrna. the cdna was recombined with the sv40 early promoter and expressed in v79 cells. three v79-derived p-450ia1-expressing cell lines (xem1, xem2, and xem3) were established. the presence of the rat cytochrome p-450ia1 cdna in these hamster cells was confirmed by southern blotting. the transcri ... | 1990 | 1692605 |
| structural characterization of natural and recombinant human granulocyte colony-stimulating factors. | granulocyte colony-stimulating factor (g-csf) is a glycoprotein which stimulates predominantly neutrophilic granulocyte colony formation in mammals. natural human g-csf (hg-csf) and recombinant hg-csf produced in chinese hamster ovary (cho) cells transfected with the cdna clone for hg-csf have been purified to apparent homogeneity for structural and biological comparison. the amino acid sequence of recombinant hg-csf, composed of 174 amino acid residues, was identical with that of natural hg-csf ... | 1990 | 1692828 |
| mutation of the gs protein alpha subunit nh2 terminus relieves an attenuator function, resulting in constitutive adenylyl cyclase stimulation. | g-proteins couple hormonal activation of receptors to the regulation of specific enzymes and ion channels. gs and gi are g-proteins which regulate the stimulation and inhibition, respectively, of adenylyl cyclase. we have constructed two chimeric cdnas in which different lengths of the alpha subunit of gs (alpha s) have been replaced with the corresponding sequence of the gi alpha subunit (alpha i2). one chimera, referred to as alpha i(54)/s' replaces the nh2-terminal 61 amino acids of alpha s w ... | 1990 | 1692962 |
| [clinical effect of recombinant human granulocyte colony-stimulating factor in bone marrow transplantation. the japan rhg-csf clinical study group]. | to evaluate the safety and efficacy of glycosylated recombinant human granulocyte colony-stimulating factor (rhg-csf) derived from chinese hamster ovary cells in bone marrow transplantation (bmt), we performed a multi-center phase ii clinical study. sixty-two bone marrow transplanted patients (46 with allograft, 16 with autograft) were enrolled in this study, and rhg-csf was administered intravenously 30 min daily at a dose of 2, 5, 10, or 20 micrograms/kg/day for 14 consecutive days from day 1 ... | 1990 | 1693489 |
| carbohydrate moieties in recombinant human thyroid peroxidase: role in recognition by antithyroid peroxidase antibodies in hashimoto's thyroiditis. | we studied the oligosaccharide moieties of recombinant human thyroid peroxidase (htpo) expressed in chinese hamster ovary (cho) cells, and the role of these glycans in htpo antigenicity in hashimoto's thyroiditis. to determine whether htpo carbohydrate moieties were n-linked, o-linked, or both, and to obtain information about the characteristics of the carbohydrate component(s), we digested htpo with deglycosylating enzymes of varying specificity. proteins in cho-tpo cells were labeled with [35s ... | 1990 | 1693564 |
| monoclonal antibodies directed against the galactose-binding lectin of entamoeba histolytica enhance adherence. | the entamoeba histolytica galactose-binding lectin is a surface glycoprotein composed of 170- and 35-kda subunits. inhibition of this lectin with galactose or anti-170 kda subunit polyclonal antibody blocks amebic adherence to target cells and colonic mucin glycoproteins. we describe the properties of 10 mab with specificity for the 170-kda subunit. based on competitive binding studies, six nonoverlapping antigenic determinants on the lectin were identified. the effect of the mab on adherence of ... | 1990 | 1693641 |
| nuclear and mitotically enhanced epitope. | salt-extracted proteins of taxol-stabilized microtubules from chinese hamster ovary cells arrested at mitosis were used to immunize mice for hybridoma production. from a group of related monoclonal antibodies (mabs), one, c9, recognized an epitope on antigens localized by immunofluorescence microscopy to interphase centrosomes and nuclei. the availability of the nuclear antigen was cell cycle-dependent; however, permeabilization of cells before fixation revealed that the antigen was present thro ... | 1990 | 1693886 |
| invasive adenylyl cyclase of bordetella pertussis. physical, catalytic, and toxic properties. | a rapid two-step purification to homogeneity of the calmodulin-activated adenylyl cyclase from urea extracts of bordetella pertussis organisms (strain 114) is described. catalytic and invasive activities are purified 30- and 177-fold, respectively, and virtually no degraded forms are found. specific activities are 0.4 mmol/min/mg and 0.5 mumol/mg of enzyme protein/mg of cell protein/min for catalytic and invasive activities, respectively. the 15 amino-terminal amino acids agree with those deduce ... | 1990 | 1693922 |
| o-linked sugar chain of human granulocyte colony-stimulating factor protects it against polymerization and denaturation allowing it to retain its biological activity. | human granulocyte colony-stimulating factor (hg-csf) is a glycoprotein carrying one o-linked sugar chain. to clarify the role of the oligosaccharide in hg-csf, some biological and physicochemical properties of the deglycosylated hg-csf and the intact factor were compared. recombinant hg-csf produced in transfected chinese hamster ovary cells was sequentially digested with neuraminidase and endo-alpha-n-acetylgalactosaminidase. the deglycosylated hg-csf was one-third as active as the intact form ... | 1990 | 1694845 |
| cloning and expression of a membrane antigen of entamoeba histolytica possessing multiple tandem repeats. | entamoeba histolytica causes amebic dysentery and amebic liver abscess, major causes of morbidity and mortality worldwide. we have used differential hybridization screening to isolate an e. histolytica-specific cdna clone. the cdna was found to encode a serine-rich e. histolytica protein (srehp) containing multiple tandem repeats. the structural motif of srehp resembles some of the repetitive antigens of malarial species, especially the circumsporozoite proteins. a recombinant trpe fusion protei ... | 1990 | 1695007 |
| cell cycle synchronization: reversible induction of g2 synchrony in cultured rodent and human diploid fibroblasts. | in accord with a set of prespecified principles of cell synchrony induction, a three-step procedure was developed to arrest cells reversibly in the g2 phase of the cell cycle. cultures of chinese hamster ovary (cho) cells were presynchronized in early s phase by sequential treatment with isoleucine deficiency and hydroxyurea blockades; then they were switched to medium supplemented with either of two agents that inhibit dna topoisomerase ii activity by different mechanisms, hoechst 33342 at 7.5 ... | 1990 | 1695009 |
| a conformational change in sindbis virus glycoproteins e1 and e2 is detected at the plasma membrane as a consequence of early virus-cell interaction. | a conformational change in the structure of sindbis (sb) virus was detected after virion attachment to baby hamster kidney cells but before internalization. the alteration was manifested as increased virion binding of certain glycoprotein e1 and e2 monoclonal antibodies (mabs) that recognized transitional epitopes. these epitopes were inaccessible to mab on native virions but became accessible to their cognate mabs in the early stages of infection. transit of virions through a low-ph compartment ... | 1990 | 1695253 |
| cloning and expression of human insulin-like growth factor binding protein 3. | insulin-like growth factors (igfs) found in plasma and other body fluids circulate in association with specific binding proteins. we report here the cloning and the nucleotide sequence of cdnas for the growth-hormone-dependent acid-stable igf binding protein, higf-bp3. the derived protein begins with a putative 27-amino acid signal peptide followed by 264 residues of the mature polypeptide. the predicted sequence contains three potential n-linked glycosylation sites and shares two region of homo ... | 1990 | 1696489 |
| human chromosome 5 complements the dna double-strand break-repair deficiency and gamma-ray sensitivity of the xr-1 hamster variant. | xr-1 is a chinese hamster ovary (cho) cell mutant which is unusually sensitive to killing by gamma rays in the g1 portion of the cell cycle but has nearly normal resistance to gamma-ray damage in late s phase. the cell-cycle sensitivity correlates with the mutant's inability to repair dna double-strand breaks (dsbs) produced by ionizing radiation and restriction enzymes. we have previously shown in somatic cell hybrids of xr-1 cells and human fibroblasts that the xr-1 mutation is a recessive mut ... | 1990 | 1697445 |
| the human pdgf receptor alpha-subunit gene maps to chromosome 4 in close proximity to c-kit. | the gene encoding the alpha-subunit of the human platelet-derived growth factor receptor (pdgfra) maps to band q11-q12 of chromosome 4 by in situ hybridization, which was confirmed by southern analysis of a chinese hamster x human cell hybrid that retains only human chromosome 4. | 1990 | 1697560 |
| il-4 acts synergistically with il-1 beta to promote lymphocyte adhesion to microvascular endothelium by induction of vascular cell adhesion molecule-1. | adhesion of lymphocytes to endothelial cells (ec) is the requisite first element in the multistep process of transmigration from blood across the postcapillary venules. selective expression of cell adhesion molecules (cm) by microvascular ec in lymphoid organs (e.g., lymph nodes) and during tissue inflammation modulates this traffic in a site-directed manner. cam synthesis by ec is regulated in turn by cytokines released in the local microenvironment. studies done largely with human umbilical ve ... | 1990 | 1698865 |
| [a clinical study of recombinant human g-csf in gynecological tumor patients with neutropenia due to chemotherapy (rg.csf clinical study group)]. | we evaluated clinical efficacy of recombinant human granulocyte colony stimulating factor (rg-csf), successfully expressed in chinese hamster ovarian cell, in gynecological tumor patients (pts) with neutropenia due to chemotherapy (ct). fifty-eight pts with advance or relapsed gynecological malignancy were entered into this study. these pts had neutropenia below 1,000/cmm by ct and in the next cycle of ct they were treated with daily rg-csf (2 micrograms/kg/day, subcutaneously) starting from the ... | 1990 | 1698901 |
| red blood cells bearing cd4 bind to gp120 covered plates and aggregate with cells expressing gp120. | full-length recombinant cd4 (rcd4) was bound to human red blood cell membranes using a low-ph incubation procedure. the red blood cells bearing recombinant cd4 (rbc-rcd4+) specifically bound to gp 120-covered plates. the binding showed a threshold effect at low rcd4 concentrations per rbc. the binding of rbc-rcd4+ to gp120 plates was not inhibited by plasma proteins (incubation in human blood plasma). preincubation of the rbc-rcd4+ with monoclonal anti-cd4 antibodies blocked the binding to the g ... | 1990 | 1698964 |
| [clinical applications of g-csf]. | granulocyte colony-stimulating factor is a 18 kd glycoprotein hormone which exhibits the following biological actions; (1) amplification and release into blood of bone marrow hematopoietic stem/progenitor cells, (2) enhancement of neutrophil production and stimulation of their release into blood and into tissues, (3) prolongation of neutrophil survival and activation of their various functions, (4) stimulation of myeloid leukemia cell growth. in patients with malignant neoplastic disorders, ther ... | 1990 | 1699497 |
| [clinical effect of recombinant human g-csf on neutropenia induced by chemotherapy for non-hodgkin's lymphoma]. | a clinical trial of recombinant human granulocyte colony-stimulating factor (rg-csf), produced by chinese hamster ovary cells, was conducted in 66 patients receiving intensive chemotherapy for non-hodgkin's lymphoma. each patient received 2 cycles of chop therapy, and one cycle of them was performed with rg-csf treatment and another one without rg-csf treatment, in a cross-over fashion. rg-csf (0.4, 2, 5, 10 micrograms/kg/day) was given intravenously or subcutaneously to each patient for 14 days ... | 1990 | 1700040 |
| polyadenylated rna sequences from vaccinia virus-infected cells selectively inhibit translation in a cell-free system: structural properties and mechanism of inhibition. | the mechanism of vaccinia virus-induced selective inhibition of host cell protein synthesis was studied in a nonpermissive (chinese hamster ovary, cho) and in a permissive mouse cell line ( l cells). small polyadenylated rnas obtained from uninfected and infected cells were fractionated into six size classes by polyacrylamide gel electrophoresis. the rnas from the first two largest fractions (greater than 500 nucleotide, nt) were translated into some low-molecular-weight polypeptides, whereas, t ... | 1990 | 1700540 |
| sequence of a cdna that specifies the uridine diphosphate n-acetyl-d-glucosamine:dolichol phosphate n-acetylglucosamine-1-phosphate transferase from chinese hamster ovary cells. | we have isolated a portion of the uridine diphosphate n-acetyl-d-glucosamine:dolichol phosphate n-acetyl-glucosamine-1-phosphate transferase gene (gtr2) from the genome of a tunicamycin-resistant clonal chinese hamster ovary cell line, 3e11. the genomic fragment was selected by its hybridization to the yeast alg-7 gene at low stringency. a 2.46-kilobase cdna was isolated from a library prepared from 3e11 mrna and probed with gtr2. the cdna contained an open reading frame that encodes a protein o ... | 1990 | 1700792 |
| [clinical evaluation of recombinant human g-csf in children with cancer]. | recombinant human granulocyte colony-stimulating factor (rg-csf), produced by chinese hamster ovary cells, was administered in 69 chemotherapy-induced neutropenic pediatric patients (pts) with malignant tumors. each pt received two cycles of the same chemotherapy and had neutropenia with absolute neutrophil counts (anc) less than 500/microliter in the first cycle. initiating 72 hours after termination of chemotherapy in the second cycle, rg-csf (2 micrograms/kg/day) was given subcutaneously or i ... | 1990 | 1701501 |
| role of dt diaphorase the cytotoxicity of menadione and 4-nitroquinoline-1-oxide in cultured mammalian fibroblastic cells. | the role of dt diaphorase on the cytotoxicity (reduction in colony formation frequency) of menadione and 4-nitroquinoline-1-oxide (4nqo) was examined in two fibroblastic cell lines (chinese hamster v79h3 cells and ng2 syrian hamster cells). the addition of dicoumarol (10(-4) m-3 x 10(-4) m), a specific inhibitor of dt diaphorase, resulted in an intensification of the cytotoxicity of menadione, supporting the hypothesis that dt diaphorase protects cells against the oxidative stress induced by qui ... | 1990 | 1701687 |