Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| rous sarcoma virus-induced changes in the pattern of phosphorylation of non-histone nuclear proteins. | we here studied the protein kinase activity and in vitro phosphorylable sites of non-histone nuclear proteins, 0.4 m nacl extracts (mostly chromosomal proteins) from chick embryo fibroblasts (cef), infected or not with a schmidt ruppin strain subgroup a of rous sarcoma virus (rsv). the infection and transformation of chick fibroblasts by rsv induced an increase in kinase activity and endogenous phosphorylation of non-histone chromosomal (nhc) proteins. the stimulation, by a change of medium, of ... | 1983 | 6190663 |
| inhibition of rous sarcoma virus assembly by treatment with 2',5' adenosine nucleotides. | we have investigated the influence of 2',5' adenosine nucleotides on the replication and transformation of cells by rous sarcoma virus (rsv). treatment with the nucleotides ppp2',5'a4 and 2',5'a4 causes a striking reduction (50-fold) in the yield of infectious progeny virus, while ppp2',5a2 and 2',5'a3 had virtually no effect. the reduction in infectivity seen with 2',5'a4 nucleotides is paralleled by a smaller but significant (three- to four-fold) reduction in the amount of particles released a ... | 1983 | 6191438 |
| immunological study of a cellular 35k phosphorylated polypeptide detected in rous sarcoma virus transformed cells. | we have immunoprecipitated a phosphoprotein of 35k daltons (35k) common to rsv-transformed chick embryo fibroblasts (cef) and rodent cells. the phosphorylation of this antigen depends on the expression of the v-src gene and contains phosphotyrosine. the pre-existing 35k protein, of cef infected de novo, was further shown to become phosphorylated shortly after the appearance of active pp60v-src, and about 1 day before morphological transformation. the experiments with rsv-transformed rodent cells ... | 1983 | 6195999 |
| detection of phosphotyrosine-containing proteins in the detergent-insoluble fraction of rsv-transformed fibroblasts by azobenzene phosphonate antibodies. | the rous sarcoma virus (rsv) oncogene product pp60src is known to trigger the acquisition of the transformed phenotype by phosphorylating host cell target molecule(s) at tyrosine residues. to identify phosphotyrosine-containing proteins, rabbit antibodies were raised against the synthetic hapten p-azobenzene-phosphonate (abp) that specifically cross-reacts with phosphorylated tyrosine. by immuno-decoration of proteins extracted from rsv-transformed mouse fibroblasts and transferred to nitrocellu ... | 1984 | 6201361 |
| differentiation and transformation of neural plate cells. | the developmental potential of presumptive neural plate cells of prestreak chick embryos (stage 1) and neural plate cells from definitive streak chick embryos (stage 4) has been examined in cell culture using specific markers that identify the major cell types in the vertebrate central nervous system. the prestreak presumptive neural plate (pspnp) cells, stage 1, assume an epithelial appearance in vitro and synthesize cellular fibronectin, but do not express markers for the neuronal, astrocytic, ... | 1984 | 6201407 |
| monoclonal antibodies protect against respiratory syncytial virus infection in mice. | twenty-five monoclonal antibodies (mab) to respiratory syncytial virus (rsv) and two to hepatitis b virus were inoculated intravenously into mice. twenty-four hours later the mice were challenged intranasally with rsv. eleven of 14 mab against fusion protein and four out of six mab against a larger glycoprotein (gp84) significantly reduced the titre of rsv in the lungs when mice were killed 5 days later. five mab against three other rsv proteins and two mab against hepatitis b virus had no signi ... | 1984 | 6201436 |
| monoclonal antibody against the carboxy terminal peptide of pp60src of rous sarcoma virus reacts with native pp60src. | a monoclonal mouse antibody has been prepared against a synthetic peptide corresponding to the six carboxy-terminal amino acids (c' peptide) of the src gene product pp60v -src of rous sarcoma virus (rsv). the antibody was able to precipitate pp60v -src and to bind pp60v -src kinase activity in a competition test, indicating that this peptide can serve as an antibody-binding site (epitope). furthermore, the finding that three out of 28 pp60src-specific tumor-bearing rabbit (tbr) sera contained an ... | 1982 | 6202510 |
| comparison of protein phosphorylations in variant a431 cells with different growth responses to epidermal growth factor. | growth of a selected variant of a431 cells (clone 29) is stimulated by epidermal growth factor (egf) in contrast to the growth inhibition caused by egf in an unselected clone, a431(8). twelve phosphoproteins from each clone were compared to determine whether unique egf-dependent substrate phosphorylations might explain the cells' differing growth responses to egf. treatment of both clone 29 and a431(8) cells with egf increased phosphorylation of the egf receptor/kinase and six cellular proteins ... | 1984 | 6202705 |
| inability of rous sarcoma virus to cause sarcomas in the avian embryo. | the injection of rous sarcoma virus (rsv) into the wing web of newly hatched chicks causes a rapidly growing sarcomatous tumour which is palpable within 1 week of inoculation; and cultures of fibroblasts derived from chick embryos (cef) and infected with rsv become rapidly transformed. genetic studies have determined that expression of a single viral gene, designated v-src, is necessary for neoplastic transformation. this gene codes for a 60,000-molecular weight phosphoprotein termed pp60spc , w ... | 1984 | 6203040 |
| characterization of a replication-defective temperature-sensitive mutant of rous sarcoma virus. | a temperature-sensitive mutant (la83) of rous sarcoma virus defective both in the transformation and replication function has been isolated and partially characterized. temperature-shift experiments showed that the defects in both the focus-forming and replication functions were late and continuous. the mutant la83 was complemented by avian leukosis viruses. complementation of la83 replication was also observed with the glycoprotein-deletion mutant, brian high-titer rsv(-) suggesting that the en ... | 1984 | 6204447 |
| isolation of proteins with kinase activity and related to pp60 src from human cells. | a protein kinase activity (pk) was associated with immunoprecipitates between polypeptides of human lymphoblastoid cells of malignant origin (raji cell line) or of their normal counterparts ( priess cell line) and antibodies directed against avian pp60 src or against the carboxyterminal hexapeptide of pp60 src. therefore, these human cells and rous sarcoma virus (rsv) transformed avian cells share antigenic determinants of pp60 src and, in particular, its carboxyterminal sequence, as well as one ... | 1984 | 6204646 |
| monoclonal antibodies for the rapid diagnosis of respiratory syncytial virus infection by immunofluorescence. | eight separate monoclonal antibodies to the long strain of respiratory syncytial virus (rsv) were tested for their utility as rapid diagnostic reagents in immunofluorescence. preliminary screening indicated that all 8 reacted with 11 field strains from three previous local rsv outbreaks and with 4 of 5 additional strains chosen because of their antigenic diversity by neutralization. two monoclonal antibodies, one each directed against a surface glycoprotein and the nucleocapsid protein, were the ... | 1984 | 6204807 |
| immunofluorescence localization of phosphotyrosine containing proteins in rsv-transformed mouse fibroblasts. | the localization of phosphotyrosine-containing proteins (p-tyr proteins) was studied by immunofluorescence microscopy employing affinity-purified azobenzyl phosphonate (abp) antibodies, which specifically cross-react with phosphotyrosine. in rous sarcoma virus (rsv)-transformed fibroblasts, after fixation followed by permeabilization with nonionic detergents, abp antibodies gave a diffuse staining of the cytoplasm and specifically decorated restricted areas of the ventral plasma membrane corresp ... | 1984 | 6205889 |
| monoclonal antibodies specific for the virion polypeptide, p27, of avian retroviruses. | the major component of the core structure of avian sarcoma leukosis viruses is a 27 kd molecular weight polypeptide, p27. spleen cells from mice immunized with the schmidt-ruppin strain of rous sarcoma virus (rsv) were fused with mouse myeloma cells (sp2/0), and hybridoma cell lines producing monoclonal antibodies to p27 were isolated. the monoclonal antibodies were all of the igg1 subclass with kappa light chains. these antibodies immunoprecipitated p27 and its precursor proteins from extracts ... | 1984 | 6205983 |
| tyrosyl kinases acquired from anchorage-independent cells by a membrane-enveloped virus. | tyrosyl kinase activity in vesicular stomatitis virus (vsv) acquired from host cells that differ in morphology was investigated. vsv grown in baby hamster kidney (bhk) cells with rounded morphology and a high efficiency of colony formation in soft agar (rous sarcoma virus [rsv]-transformed and suspension bhk cells) was compared with vsv grown in bhk cells with a flattened morphology and lower efficiency of colony formation in soft agar (rsv-infected revertant and control bhk cells). tyrosyl kina ... | 1984 | 6206078 |
| preparation and characterization of antibodies to o-phosphotyrosine and their use for identification of phosphotyrosine-containing proteins. | to facilitate the identification of phosphotyrosine (p-tyr)-containing proteins, rabbit polyclonal antibodies and mouse monoclonal antibody specifically reactive to p-tyr were prepared by hyperimmunizing the animals with p-tyr-conjugated bovine serum albumin or poly-l-lysine. as determined by a solid-phase radioimmunoassay and an enzyme-linked immunosorbent assay, the antibodies reacted with p-tyr-conjugated target antigens but not with those conjugated with phosphoserine (p-ser) or phosphothreo ... | 1984 | 6210255 |
| defective regulation of immune responses in respiratory syncytial virus infection. | the relationship of suppressor cell numbers and function to virus-specific ige response was determined in 72 infants with respiratory syncytial virus (rsv) infection. monoclonal antibodies to membrane antigens were used to enumerate okt4 and okt8 antigen-positive cells, and suppressor cell function as quantitated by the degree of suppression of lymphocyte mitogenesis induced by incubation of lymphocyte cultures with histamine. patients with bronchiolitis had fewer okt8-positive cells during conv ... | 1984 | 6236259 |
| biosynthesis in vitro of mono- and di-sialosylgangliosides from gangliotetraosylceramide by cultured cell lines and young rat brain. structure of the products, and activity and specificity of sialosyltransferase. | incubations in vitro of ga1, labeled with 3h in the terminal d-galactopyranosyl group, with nonradioactive cmp-neunac in the presence of homogenates of c21 rat brain glial cells, nie mouse neuroblastoma cells, 3t3 mouse fibroblasts, sv 40-transformed 3t3 cells, chick embryo fibroblasts, rous sarcoma virus-transformed chick embryo fibroblasts, and 9-day old rat brain resulted in all cases in the formation in high yield of gm1b, in which the neuraminidase-labile neunac group is linked at o-3 of th ... | 1980 | 6243513 |
| purine base composition analysis of normal and tumor rat dna. | chemical and viral induced rat tumors were analyzed for their purine base composition and compared to normal tissue dna's. the tumors were induced by 7,12-dimethylbenz[a]anthracene (dmba), 20-methylcholanthrene (mc), 3,4-benzopyrene (bp), 1,2-dimethylhydrazine (dmh) and rous sarcoma virus (rsv). normal dnas were extracted from colon, caecum, liver, spleen and embryo and used as reference standards for base composition of normal rat dna. the composition of purines was obtained by spectrophotometr ... | 1980 | 6244115 |
| mutant and recombinant avian retroviruses with extended host range. | avian retroviruses of subgroups b and d efficiently infect chicken (c/e) but not turkey (t/bd) cells. we describe here three variants of subgroup b and d viruses that infect both cell types equally well. one of these viruses, ntre-4, was a recombinant between transformation-defective prague (pr) strain rous sarcoma virus (rsv) subgroup b and the endogenous virus rav-0; the second, sr-de-1, was a recombinant between schmidt-ruppin rsv subgroup d and defective endogenous virus information. t1 olig ... | 1980 | 6244565 |
| recombinants between endogenous and exogenous avian tumor viruses: role of the c region and other portions of the genome in the control of replication and transformation. | endogenous retroviruses of chickens are closely related to exogenous viruses isolated from spontaneous tumors in the same species, yet differ in a number of important characteristics, including the ability to transform cells in culture, ability to cause sarcomas or leukemias, host range, and growth rate in cell culture. to correlate these differences with specific sequence differences between the two viral genomes, the genome rna of transforming subgroup e recombinants between the prague strain ... | 1980 | 6245229 |
| transformation of rat cells by fusion-infection with rous sarcoma virus. | the transformation of a rat cell line, 3y1, by nonmammalian tropic strains of avian sarcoma virus was tested using cell-virus fusion mediated by sendai virus or polyethylene glycol. furthermore, the establishment of several transformed 3y1 cell clones induced by the schmidt-ruppin strain of rous sarcoma virus (rsv), its derivative mutants, and the bryan high-titer strain of rsv is reported. the presence and expression of the viral genomes in these cells were examined, and all transformed cell cl ... | 1980 | 6247511 |
| alignment of the peptides derived from acid-catalyzed cleavage of an aspartylprolyl bond in the major internal structural polypeptide of avian retroviruses. | the major internal structural polypeptide (p27) of rous sarcoma virus (rsv), and the analogous polypeptide (p27(0)) of rous-associated virus-o (rav-o), an endogenous virus released spontaneously by some chicken cells) have been cleaved selectively at a single aspartylprolyl peptide bond to yield two fragments. the nh2- and cooh-terminal amino acid sequences of p27 and p27(0) and their mild acid-cleavage fragments have been determined. these results show the existence of an identical cleavage sit ... | 1980 | 6248540 |
| characterization of tumors induced in adult macaca mulata monkeys with carr-zilber strain of rous sarcoma virus. | the carr-zilber strain of rous sarcoma virus is highly oncogenic for adult monkeys of the species macaca mulata. in the present study, we examined some characteristics of tumor growth when the tumor either regressed or progressed until it killed its host. we followed the kinetics of antibody formation to antigens coded by cz-rsv in animals with a different course of tumor disease. the sera of animals tested contained virus-neutralizing antibodies, in addition to gs antibodies. the results are di ... | 1980 | 6248800 |
| rous sarcoma regression in seven highly inbred lines of white leghorns. | response to rous sarcoma virus (rsv)-induced tumors was studied in regional poultry research laboratory (rprl) lines 61, 63, 72, 100, 151, and 15i5 and in reaseheath line c, all highly inbred white leghorn stocks. virus inoculations were made in chickens at 6 weeks of age. tumors were scored subjectively for size on a regular basis and in some instances a tumor profile index (tpi) was assigned which characterized tumor development over a 10 week period for each chicken (tpi 1 = complete regressi ... | 1980 | 6250136 |
| experimental models for study of common respiratory viruses. | numerous epidemiological studies have shown that there is excess respiratory disease morbidity in areas of high atmospheric pollution, implying an interactive effect on the clinical illness associated with these common infections. the principal etiologic agents of human respiratory infections are respiratory syncytial virus (rsv), influenza viruses (iv), parainfluenza virus types 1 and 3 (p1, p3), adenoviruses (ad), rhinoviruses (rv) and mycoplasma pneumoniae (mpn). understanding the pathogenesi ... | 1980 | 6250807 |
| detection of viral markers and incomplete viral genome rescue from asv transformed rodent cells. | two non-virogenic rat cell lines twerc and fr transformed with pr-rsv and fsv, respectively, were analyzed. both these cell lines contained vrna, but only in twerc cells was the major viral polypeptide p27 synthetized. transforming virus can be rescued from both cell lines only after fusing them with chicken fibroblasts preinfected with avian leukosis viruses of subgroup a, c, d, f and both td mutants of pr-rsv-c and b77-c. similarly, virus was rescued in experiments in which qef infected with r ... | 1980 | 6250919 |
| budding of rous sarcoma virus and vesicular stomatitis virus from localized lipid regions in the plasma membrane of chicken embryo fibroblasts. | the origin of the envelope lipids acquired by rous sarcoma virus (rsv) and vesicular stomatitis virus (vsv) during budding from the plasma membrane of chicken embryo fibroblasts was examined. several differences were observed between the lipid composition of rsv and the plasma membrane. when the phospholipid composition of the cells was modified by growing them in the presence of the choline analogues, n,n-dimethylethanolamine or l-2-amino-1-butanol, the phospholipid composition of the virus was ... | 1980 | 6251073 |
| adhesion plaques of rous sarcoma virus-transformed cells contain the src gene product. | another intracellular location of the rous sarcoma virus (rsu) src gene product (pp60src) has been detected within rsv-transformed cells by indirect immunofluorescence. by using rabbit anti-tumor serum specific for pp60src, a speckled pattern of fluorescence was found on the ventral surface of rsv (schmidt-ruppin strain)-transformed normal rat kidney cells. several tests indicated that this pattern was specific for pp60src. in addition, interference-reflection microscopy was used to visualize ce ... | 1980 | 6251464 |
| ["pharaoh" line culture of japanese quail cells as a leukosis-free system for virus reproduction]. | contamination of japanese quail, strain pharaoh, cell culture with oncogenous and infectious avian viruses was studied. the susceptibility of the embryonal cell cultures of the japanese quail, strain pharaoh, to measles, parotitis and fixed rabies viruses was also determined. it was found that the sera of pubertal quails had no antibody to rous sarcoma virus (rsv), strains brian, rsv (rav-1), schmidt-ruppin, carr-zilber, as well as to marek's disease and newcastle disease viruses. no reverse tra ... | 1980 | 6251636 |
| fusion of transformed human cells by simian retroviruses. | mason-pfizer monkey virus (mpmv), baboon endogenous virus (baev) and simian sarcoma virus associated virus (ssav) induced fusion in cultured human cells derived from tumors or transformed in vitro. not only virus-transformed cells, but also cells transformed spontaneously by 4-nitroquinoline 1-oxide (4-nqo) treatment or by 60co-gamma ray irradiation were fused by these simian retroviruses. non-transformed cells derived from normal human embryos were not fused by any of these viruses. of these tu ... | 1980 | 6252085 |
| aggregation properties of chondrocytes infected with a temperature-sensitive mutant of rous sarcoma virus. | aggregation capacity of chicken embryo chondrocytes decreases when transformed by rous sarcoma viruses. cell-to-cell aggregation capacity of chondrocytes infected with a t class temperature-sensitive mutant (tsny68) (with the temperature-sensitive lesion at the src gene) of rous sarcoma virus is dependent upon the temperature at which these cells are grown. when grown at the permissive temperature (36 degrees c), where the transforming gene is expressed, aggregation capacity was lower than norma ... | 1980 | 6252220 |
| transformation of nih-3t3 mouse cells by avian retroviral dnas. | nih-3t3 cells were found to be transformable by rsv dna in the absence of progeny virus production. cells transformed by intact rsv dnas contained rescuable rsv genomes that were integrated into cellular dna and were colinear with unintegrated rsv dna. nih-3t3 cells were also transformable by subgenomic fragments of rsv dna, synthesized in vitro or generated by restriction endonuclease digestion of intracellular rsv dna. these cells did not contain rescuable rsv genomes but did contain rsv dna f ... | 1980 | 6253192 |
| studies on the structure and function of the avian sarcoma virus transforming-gene product. | the protein kinase activity associated with pp60src of a mutant of rsv temperature sensitive for transformation was shown to be sixfold more labile than that of its wild-type parent at 45 degrees c when pp60src's synthesized in vitro were compared. thus, a mutant that is temperature sensitive for transformation has a temperature-sensitive protein kinase activity. analysis of the levels of protein kinase activity in immunoprecipitates from cells infected with four different temperature-sensitive ... | 1980 | 6253224 |
| molecular events in cells transformed by rous sarcoma virus. | the rous sarcoma virus (rsv) transforming gene product has been identified and characterized as a phosphoprotein with a molecular weight of 60,000, denoted pp60src. partially purified pp60src displays a closely associated phosphotransferase activity with the unusual specificity of phosphorylating tyrosine residues in a variety of proteins. that the enzymatic activity observed is actually encoded by the rsv-transforming gene is indicated by the comparison of the pp60src-protein kinase isolated fr ... | 1980 | 6253501 |
| generation of nondefective rous sarcoma virus by asymmetric recombination between deletion mutants. | a replication-defective deletion mutant of prague rous sarcoma virus (rsv), which lacks functional gag, pol, and env genes, was crossed with a transformation-defective deletion mutant derived from schmidt-ruppin rsv. transformation- and replication-competent viruses were generated in the cross. characterization of one of these rescued viruses indicated that it was a nondefective recombinant containing the src gene of the replication-defective mutant plus the replicative genes of the transformati ... | 1980 | 6253679 |
| nucleolar ultrastructure and transcription of preribosomal rna in rous sarcoma virus-transformed chick embryo fibroblasts treated with alpha-amanitin. | uninfected and rous sarcoma virus (rsv)-transformed chick embryo fibroblasts (cef) were exposed to various concentrations of alpha-amanitin for different lengths of time. at a concentration of 4 micrograms alpha-amanitin/ml, rsv-transformed cells were shown to maintain a normal rate of transcription of all classes of rna, whereas in uninfected cells transcription was reduced to a very low level. these observations cannot be accounted for by a difference in the penetration rate of alpha-amanitin ... | 1980 | 6253713 |
| specific dephosphorylation of membrane proteins in rous sarcoma virus-transformed chick embryo fibroblasts. | chick embryo fibroblasts (cef) infected with avian sarcoma virus become rapidly transformed as a result of expression of the viral src gene in the form of a single polypeptide of molecular weight 60,000 (pp60src) with protein kinase activity and suggested preferential association with the plasma membrane. studies with normal avian and mammalian cells have revealed the presence of an antigenically related protein which seems to have similar kinase activity, but which is present at less than 1% of ... | 1980 | 6253800 |
| unifected avian cells contain structurally unrelated progenitors of viral sarcoma genes. | a single gene, src of rous sarcoma virus (rsv) coding for a protein of pp60src, is responsible for the transformation of fibroblasts. dna sequences homologous to src (the endogenous sarc) are presented in uninfected cells of chickens and other vertebrates. endogenous nucleotide sequences have also been found in the putative transforming genes of mc29 (ref. 6) and avian erythroblastosis virus. these viruses, however, induce different spectra of tumours in animals. from analysis of a new avian sar ... | 1980 | 6253807 |
| studies on recombination in heterologous crosses of rous sarcoma virus. | ts mutants in src from the prague and schmidt-ruppin strains of rous sarcoma virus (rsv) were used to superinfect chicken and quail cells chronically infected with the bryan strain of rsv. no wild-type recombinants and few double-defective virions were produced. these results indicate that genetic recombination does not occur with high frequency in these heterologous crosses even if all infectious virus is derived from doubly infected cells. | 1980 | 6255082 |
| stimulation of growth rate of chondrocytes by rous sarcoma virus is not coordinated with other expressions of the src gene phenotype. | infection and transformation of chondrocytes by rous sarcoma viruses (rsvs) (schmidt-ruppin, prague) stimulated the rate of cell growth. in contrast, several transformation-defective (td) mutants (tdpra, tdny105, tdny106, tdny107, and tdny108) retaining various sizes of the src gene did not stimulate cell growth, indicating that the stimulation of growth of chondrocytes is due to the function of the src gene. with the use of various t (transformation)-class temperature-sensitive (ts) mutants of ... | 1980 | 6255190 |
| synthesis and processing of viral glycoproteins in two nonconditional mutants of rous sarcoma virus. | we have studied the pattern of glycoprotein synthesis in two nonconditional mutants of rous sarcoma virus. one mutant, se33, produces no viral particles but synthesizes pr92env, which is cleaved intracellularly to mature glycoproteins. the second mutant, se521, encodes a gpr92env which is not cleaved to gp85 or gp37 and therefore produces virions with the phenotype of bryan rsv(-) or ny8. neither of these mutants have detectable genomic deletions. the study of these mutants has led to the follow ... | 1980 | 6255212 |
| analysis of the secondary and tertiary structures of rous sarcoma virus rna. | the secondary and tertiary structures of the 35s rna of rous sarcoma virus have been investigated. t1 rnase partial digests have been first resolved into their components by gel electrophoresis under non denaturing conditions and then each component analyzed further by various techniques. more than one hundred structured fragments have thus been isolated and shown to consist of several individual nucleotide sequences located far apart on the genome. on the basis of the results, a cloverleaf mode ... | 1980 | 6255413 |
| a survey of virus infections of the respiratory tract of cattle and their association with disease. | a total of 1590 caves were investigated between may 1972 and december 1975. twenty-two per cent were treated for respiratory disease and 2 . 5% died of pneumonia. almost 80% of the respiratory illness occurred in six sharp outbreaks. samples of virology were collected routinely from 127 healthy calves and from 354 calves treated for respiratory signs and comprised 1143 nasopharyngeal swabs and 1069 sera. virus infections were detected on 540 occasions including 135 by parainfluenzavirus type 3 ( ... | 1980 | 6256435 |
| role of src gene in growth regulation of rous sarcoma virus-infected chicken embryo fibroblasts. | we report here a study of the mechanisms leading to loss of growth control in chicken embryo fibroblasts transformed by rous sarcoma virus (rsv). we have been particularly concerned with the role of the src gene in this process, and have used rsv mutants temperature sensitive (ts) for transformation to investigate the nature of the growth regulatory lesion. the two principal findings were (1) the stationary phase of the cell cycle (g1) in chick embryo fibroblasts seems to have two distinct regul ... | 1980 | 6256641 |
| [rous virus-induced sarcoma study of macaca mulatta monkeys]. | the carr-zilber strain of rous sarcoma virus is highly oncogenic for adult monkeys of the species macaca mulata. in the present study the authors examined some characteristics of tumor growth, when the tumor either regressed or progressed until it killed its host. the kinetics of antibody formation to antigens coded as cz-rsv was followed in animals with a different course of tumor disease. the sera of animals under test contained virus-neutralizing antibodies in addition to gs antibodies. | 1981 | 6256976 |
| pneumonia: an eleven-year study in a pediatric practice. | data from an 11-year study of acute lower respiratory tract illness were analyzed to provide added insight into the causes and patterns of occurrence of pneumonia in an outpatient pediatric population. over 80% of all episodes of pneumonia occurred in children less than seven years of age; the peak attack rate was observed in 2-4-year-old children. a virus or mycoplasma pneumoniae was isolated from 24% of children with pneumonia; 57% of all episodes occurred during outbreaks for which a viral or ... | 1981 | 6257108 |
| rsv-transformed mammalian cells: an analysis of rnas specific for exogenous and endogenous viruses. | a marked decrease in expression of rsv-specific sequences was observed in cryptovirogenic rsv-transformed rvp3 murine cells during passaging. simultaneously an increase in expression of sequences specific for c-type murine viruses was observed both in these cells and other rsv-transformed murine cells. no activation of c-type viral genome was detected in spontaneous murine lung tumors and in methylcholanthrene-induced murine tumors. four types of virus specific rnas were found in xc cells: the 3 ... | 1980 | 6257202 |
| identification of a functional promoter in the long terminal repeat of rous sarcoma virus. | specific initiation of transcription of rous sarcoma virus by rna polymerase ii was obtained in a cell-free system using cloned rsv dna as template. the site of initiation is located in the common "c" region of the long terminal repeat (ltr), 23 bp downstream from the promoter-like sequence tatttaag. this finding indicates that the basic information necessary for rsv transcription lies within the viral genome. | 1980 | 6257399 |
| ornithine decarboxylase induction during b1 progression of normal and rous sarcoma virus-transformed cells. | ornithine decarboxylase (odc) induction during g1 phase of the cell cycle was compared in rat-1 fibroblasts and in rat-1 fibroblasts transformed by the b77 wild-type rous sarcoma virus (rsv) and by the thermosensitive mutant la24/rsv. in rat-1 cells, maximal enzyme activity detectable at mid g1 declined to basal levels by g1-s. the odc increase was inhibited by actinomycin d and cycloheximide and was dependent on the addition of serum growth factors. rat-1 (b77 wild-type rsv) cells expressed a g ... | 1980 | 6258784 |
| increased growth of rsv-induced tumors in chickens partially tolerant to mhc alloantigens. | chickens with b2b2 mhc genotypes were made partically tolerant to b5 mhc cell-surface antigens and the fate of their rous-sarcoma-virus (rsv)-induced tumors was determined. b2b2 chickens partially tolerant to viable or lysed white blood cells (wbc) or viable red blood cells (rbc) from b5b5 chickens had a significantly higher incidence of tumor progression than untreated, pbs-treated, or b2b2 chickens inoculated with wbc from other b2b2 chickens. the criteria for tolerance were absence of antibod ... | 1981 | 6259056 |
| in vitro phosphorylation of the 36k protein in extract from rous sarcoma virus-transformed chicken fibroblasts. | when cell-free extracts of chickens embryo fibroblasts transformed by rous sarcoma virus (rsv) were incubated with [gamma-32p]atp, a protein having a mr of 36,000 was phosphorylated. two-dimensional electrophoresis of a mixture of phosphorylated proteins formed in vitro and in vivo showed that they are indistinguishable. the in vitro phosphorylation of the mr = 36,000 protein was completely inhibited by serum isolated from rabbit bearing tumor formed by rsv. in addition, phosphorylation of the 3 ... | 1981 | 6259148 |
| external cell surface protein phosphorylation in normal and rous sarcoma virus transformed chick embryo fibroblasts. | normal and rous sarcoma virus (rsv)-transformed chick embryo fibroblasts growing on plastic dishes were incubated with atp (gamma 32p) in situ to detect external cell surface protein kinase activity. under the conditions employed, 32p was incorporated exclusively into proteins, specifically those at the external cell surface, as radioactivity was removed by trypsin treatment of labeled whole cells. in addition, exogenous histones were phosphorylated when added to the reaction mixture. cyclic nuc ... | 1981 | 6259183 |
| detection of respiratory syncytial, parainfluenza type 2, and adenovirus antigens by radioimmunoassay and enzyme immunoassay on nasopharyngeal specimens from children with acute respiratory disease. | four-layer antispecies radioimmunoassay (ria) and enzyme immunoassay (eia) procedures were developed for the detection of respiratory syncytial virus (rsv), parainfluenza type 2 virus, and adenovirus antigens in nasopharyngeal specimens from children hospitalized for acute respiratory disease. polystyrene beads (ria) or flat-bottomed polystyrene microtiter plates (eia) were used as the solid phases, guinea pig anti-virus immunoglobulins were used as the captive antibodies, rabbit anti-virus immu ... | 1981 | 6259198 |
| antisera from mice and rats incubated with syngeneic rous sarcoma cells. | cdf1, (balb/c x dba/2)f1, mice were repeatedly inoculated with transplantable mouse rous sarcoma (sr-cdf1) cells which were half-killed by 60co-irradiation beforehand to attain prolonged immunization. the sera obtained from these mice contained antibodies against the src and gag gene products of rous sarcoma virus (rsv). on the other hand, fischer rats inoculated with syngeneic rat rous cells transformed by bryan high titer strain of rsv (bh(-)-3y1) produced antibodies against the gag gene produ ... | 1980 | 6259386 |
| integration of rous sarcoma virus dna during transfection. | we have investigated the organization and integration sites of rous sarcoma virus (rsv) dna in nih 3t3 mouse cells transformed by transfection with unintegrated and integrated donor rsv dnas. rsv dnas of different cell lines transformed by unintegrated donor dna were flanked by different cellular dna sequences, indicating that rsv dna integrates at multiple sites during transfection. the rsv genomes of cells transformed by transfection were colinear with unintegrated rsv dna, except that deletio ... | 1981 | 6260381 |
| sodium and rubidium uptake in cells transformed by rous sarcoma virus. | rates of uptake and intracellular concentrations of monovalent cations were measured in virus-transformed and nontransformed chick embryo (ce) cells. uptake of 22na+ into cells transformed by the bh strain of rous sarcoma virus (rsv-bh) (ce-bh) was about double the rate of uptake into ce cells, or cells transformed by the schmidt-ruppin strain (rsv-sr): ce-sr. likewise, the rate of efflux of 22na+ was greater in ce-bh cells than in ce or ce-sr cells. the greater permeability of ce-bh cells to na ... | 1981 | 6260819 |
| secondary structural features in the 70s rnas of moloney murine leukemia and rous sarcoma viruses as observed by electron microscopy. | the secondary structural features in the 70s rnas of the prague strain of avian rous sarcoma virus, subgroup a (pr-rsv-a), and moloney murine leukemia virus (m-mulv) were compared by electron microscopy. the pr-rsv-a genome contained two subunits joined by a linkage structure as in the genomes of m-mulv and other mammalian retroviruses. in both viral genomes, a highly reproducible hairpin occurred at about 70 nucleotides from the 5' end of each subunit and contained 320 +/- 8 nucleotides. the st ... | 1981 | 6260992 |
| independent expression of avian sarcoma virus in doubly infected chicken embryo fibroblasts. | infection of a chicken cell with avian sarcoma virus requires division of the infected cell before synthesis of infectious progeny is initiated. this requirement for a cell division for the complete expression of avian sarcoma virus has been examined further with chicken embryo fibroblasts infected with two distinct viruses. chicken cells infected with and producing a mutant of rous sarcoma virus temperature sensitive for transformation (tsla24pr-a) were arrested in g0 by depletion of serum fact ... | 1981 | 6261016 |
| decrease in the levels of nuclear rna precursors for alpha 2 collagen in rous sarcoma virus transformed fibroblasts. | we have examined the levels of type i alpha 2 collagen rna precursors, containing both intron and exon sequences in nuclear rna preparations of chick embryo fibroblasts (cef) and of cef transformed by the schmidt-rupin strain of rous sarcoma virus (rsv). we have used two different fragments of chick alpha 2 collagen genomic dna as hybridization probes in s1 mapping experiments. each of these dna probes contains an entire intron. our results indicate that the levels of the primary transcript of a ... | 1981 | 6262721 |
| structural and functional domains of the rous sarcoma virus transforming protein (pp60src). | the transforming protein (pp60src) of the rous sarcoma virus (rsv) is a phosphoprotein with the enzymatic ability to phosphorylate tyrosine in protein substrates. previous work has indicated that the bulk of pp60src may be attached to the plasma membrane of infected cells. in an effort to better understand the mechanism by which pp60src induces the neoplastic phenotype, we have characterized further the attachment of pp60src to the plasma membrane, and we have identified separate molecular domai ... | 1981 | 6262821 |
| regulation or procollagen messenger ribonucleic acid levels in rous sarcoma virus transformed chick embryo fibroblasts. | using cloned cdnas for pro-alpha 1 and pro-alpha 2 collagen messenger ribonucleic acid (mrna), we have investigated the regulation of collagen mrna levels in rous sarcoma virus (rsv) transformed chick embryo fibroblasts (cef). we find that both pro-alpha 1 and pro-alpha 2 mrna levels are decreased approximately 10-fold in cef transformed by either the bryan high-titer strain or the schmidt-ruppin strain of rsv. using temperature-sensitive mutants in the transforming gene src, we also investigate ... | 1981 | 6263317 |
| transforming proteins of some feline and avian sarcoma viruses are related structurally and functionally. | transformation of chicken cells by fujinami sarcoma virus (fsv), prc ii or y73 (three independently isolated avian sarcoma viruses that are replication-defective and lack the rous sarcoma virus src gene) resulted in significant elevation (4-13 fold) of phosphotyrosine levels in cellular protein. the gag-related proteins encoded by these avian sarcoma viruses (asvs) were all associated with tyrosine-specific protein kinase activity when assayed in immune complexes and were phosphorylated at both ... | 1981 | 6263483 |
| vinculin: a cytoskeletal target of the transforming protein of rous sarcoma virus. | vinculin, a protein associated with the cytoplasmic face of the focal adhesion plaques which anchor actin-containing microfilaments to the plasma membrane and attach a cell to the substratum, contains 8-fold more phosphotyrosine in cells transformed by rous sarcoma virus than in uninfected cells. because the transforming protein of rsv, p60src, is a protein kinase that modifies cellular proteins through the phosphorylation of tyrosine and because phosphotyrosine is a very rare modified amino aci ... | 1981 | 6263485 |
| increase in s-adenosyl-l-methionine decarboxylase activity during the transformation of chick embroy fibroblasts by rous sarcoma virus. | the increase in s-adenosyl-l-methionine decarboxylase activity in chick embryo fibroblasts after infection with rous sarcoma virus has been studied. it has been shown that enzyme levels in transformed cells were two or three times higher than those of the non-infected controls. the activity of this enzyme was not elevated in chick embryo fibroblasts infected with a temperature sensitive mutant of rous sarcoma virus (rsv-t5) at 42 degrees c, the non-permissive temperature. when the temperature of ... | 1980 | 6263805 |
| a third class of avian sarcoma viruses, defined by related transformation-specific proteins of yamaguchi 73 and esh sarcoma viruses. | the gag-linked transformation-specific protein (polyprotein) p80 of esh avian sarcoma virus (esv) has been compared by tryptic peptide mapping with the homologous protein p90 of yamaguchi 73 avian sarcoma virus (y73). p80 of esv and p90 of y73 were found to share all four of their major nonstructural, transformation-specific, methionine-containing peptides and to have at least seven cysteine-containing transformation-specific peptides in common. two nonstructural cysteine-containing peptides uni ... | 1981 | 6264485 |
| immunoelectron microscopic localization of rous sarcoma virus structural protein p27 in infected chicken embryo fibroblasts. | the immunoperoxidase technique was employed to localize, at the ultrastructural level, protein pr76 (a precursor of the 'gag' gene protein of avian leukemia and sarcoma viruses) in chick embryo cells infected with rsv-rav-2 virus. the protein was confined to free and membrane-bound ribosomes. this was often particularly conspicuous in the perinuclear region. no staining was found in the ergastoplasmic cisternae, in the golgi apparatus, or in the nucleus. this pattern of localization is compatibl ... | 1980 | 6265399 |
| inhibitory effects of an aromatic retinoid (ro 10-9359) on viral tumorigenesis. | prophylactic treatment of hamsters and chickens with an aromatic retinoid (ro 10-9359) inhibited rous sarcoma virus (rsv) tumorigenesis. retinoid administration to chickens with rsv-induced tumors resulted in tumor regression and/or confinement to the primary site. the retinoid also exerted a therapeutic effect on shope virus papilloma development in the skin of rabbits. | 1980 | 6265402 |
| the expression of glial fibrillary acidic protein in a rat cerebellar cell line. | a rat cerebellar cell line, wc5, derived by transformation with rous sarcoma virus, which is temperature-sensitive for transformation (ts-rsv), can be induced to express glial fibrillary acidic protein (gfap). immunofluorescence, radioimmune assay, and electron microscopy studies show that gfap is expressed in wc5 cells grown at the nonpermissive temperature (npt), but not at the permissive temperature (pt) for transformation. gfap is first detectable about 3 days after incubating cells at the n ... | 1981 | 6265476 |
| hybrid plasmids carrying part of the rous sarcoma virus-specific leader sequence. | 'strong-stop' dna, complementary to the 5'-terminal 101 nucleotides of rous sarcoma virus genomic rna and subgenomic mrnas can be used to isolate rsv-specific mrna from infected cells. to analyse leader sequences of these mrnas and to study the mechanism of their translation, relatively large quantities of strong-stop dna are required. the construction of four plasmids carrying useful strong-stop dna sequences for mrna isolation is described. one such hybrid plasmid carries a dna insertion conta ... | 1981 | 6266483 |
| neuraminidase activity and cell surface sialic acid turnover in rous sarcoma virus transformed chick embryo fibroblasts. | neuraminidase activity of rous sarcoma virus transformed chick embryo fibroblasts (rsv-cef) was assayed using an exogenous substrate, neuraminlactitol-[3h], and endogenous, cell surface [14c]-n]-acetyl-neuraminic acid. rsv-cef had higher neuraminidase activity toward both substrates than did chick embryo fibroblasts (cef) or nontransformed, rous associated virus infected cef (rav-cef). the total sialic acid content of rsv-cef was lower than cef or rav-cef, and more of the total sialic acid was a ... | 1981 | 6266645 |
| electron spin resonance of growing normal and virus-transformed cells. | a g = 2.003 esr signal, attributed to a free radical localized in hela cell nuclei and mitochondria but absent in membranes and cytoplasm, has been studied as a function of the culture growth cycle in normal (nrk and 3t3) and virus transformed (nrk/rsv and 3t3/sv40) cells. for both these cell pairs, the signal is higher during the "lag" stage and lower during the "growth" stage. the average specific intensity of the signal in normal cells is about twice that in virus-transformed cells. however, ... | 1981 | 6266648 |
| complementing mhc- and non-mhc-linked genes and resistance to avian sarcoma virus-induced tumours in inbred lines of chickens. | schmidt-ruppin rous sarcoma virus, subgroup b (sr-rsv-b), was inoculated into the wingwebs of chickens from three partially congenic inbred lines, g-b1, g-b2 and g-b3, homozygous for different mhc (b region) haplotypes (genotypes = b1/b1, b2/b2 and b3/b3 respectively). all birds developed tumours but only the g-b2 line resisted progressive tumour growth. birds from lines g-b1 and g-b3 approached 100% susceptibility to progressive tumour growth, whereas most (g-b1 x g-b3) f1 hybrids were resistan ... | 1981 | 6267140 |
| b-haplotype influence on marek's disease, rous sarcoma, and lymphoid leukosis virus-induced tumors in chickens. | experiments were conducted to establish whether b-haplotype genes that determine resistance to rsv-induced tumors would also influence resistance to marek's disease and lymphoid leukosis. matings of line 6(3) x 15(1) f3 or f4 breeders segregating for the ea-b locus antigens that are markers for b2 and b5 haplotypes of the b major histocompatibility complex were made to produce b2b2, b2b5, and b5b5 chicks. the chicks were infected with a standard inoculum of one of the three tumor viruses in sepa ... | 1981 | 6267578 |
| differential effects of transforming avian rna tumor viruses on avian macrophages. | functionally differentiated chicken macrophages were derived by in vitro differentiation of embryonic yolk sac cells and were characterized by several macrophage-specific cell markers. uniform, infected, virus-producing cultures were obtained after exposure of these macrophages to avian myoblastosis virus (amv), avian myelocytomatosis virus (mc29), myeloblastosis-associated virus (mav-2), and prague strain of rous sarcoma virus (pr-b rsv). both amv and mc29 induced morphological transformation t ... | 1981 | 6267600 |
| retroviruses as mutagens: insertion and excision of a nontransforming provirus alter expression of a resident transforming provirus. | integration of retroviral dna appears to occur randomly in host genomes, suggesting that retroviruses can act as insertion mutagens. we have confirmed this prediction by showing that the nontransforming retrovirus, moloney murine leukemia virus (m-mulv), can insert its provirus within the selectable target provided by a single provirus in a clonal rat cell line (b31) transformed by rous sarcoma virus (rsv). analysis of over 60 morphological revertants of m-mulv-superinfected b31 cells revealed t ... | 1981 | 6268304 |
| electrochemical modification of vesicular stomatitis virus glycoprotein by host cell transformation. | electrochemical properties of the glycoprotein of vesicular stomatitis virus (vsv) grown in rous sarcoma virus (rsv)-transformed cells was compared with that of its counterpart grown in nontransformed cells. in deae-sephadex column chromatography, the glycoproteins of vsv derived from transformed cells appeared more heterogeneous and had a tendency to elute with higher concentrations of nacl than those from nontransformed cells. in isoelectric focussing, the glycoproteins of vsvs derived from tr ... | 1981 | 6268946 |
| acute non-bacterial infections of the respiratory tract in singapore children: an analysis of three years' laboratory findings. | a retrospective study of the laboratory results on respiratory specimens received from children under 12 years of age between january 1977 and december 1979 was carried out. these children were either hospital patients, usually with lower respiratory infections, or outpatients on the influenza surveillance programme. the overall virus isolation rate was 26.8%, and the isolation rate among hospital patients, 38.5%. epidemics or outbreaks were associated with infections due to the influenza viruse ... | 1981 | 6269479 |
| helper virus-dependent rsv rescue from two lines of hamster cells transformed in vivo by xc rsv. | newborn hamsters were inoculated with chicken sarcoma tissue produced by xc rsv which had been rescued by transfection from xc cells. tumours with a latency of up to 20 months appeared in all inoculated hamsters. three tumour cell lines were successfully established for in vitro growth and cloned. the virus was rescued from the pr rsh-9 cell line by cell fusion with chicken fibroblasts and from the other two lines (pr rsh-12 and pr rsh-14) and clones only if chicken fibroblasts used for fusion h ... | 1981 | 6270026 |
| comparison of camp-dependent protein kinase in normal and rous sarcoma virus transformed chick embryo fibroblasts. | camp-dependent protein kinase was compared in normal and rous sarcoma virus transformed chicken embryo fibroblasts. total camp binding activity and camp-dependent histone kinase activity were unaltered by rsv transformation. the apparent km for activation of histone kinase activity by camp was 35 nm in both normal and transformed cells. using 8-n3-camp photoaffinity labeling, normal and transformed cells were also found to contain equal quantities of a single 42,000 mr regulatory sub-unit isoenz ... | 1981 | 6270200 |
| lack of correlation between pp60src kinase activity and transformation parameters in cells infected with temperature-conditional mutants of rous sarcoma virus. | the pp60src kinase activity of cells infected with temperature-conditional mutants of rous sarcoma virus (rsv), which induce only a partial transformation, was compared to the pattern of transformation parameters induced by these mutants. the tsgi251-infected cells were thermosensitive for hexose transport, fibrinolysis, morphological alterations and pp60src kinase activity, but cold-sensitive for loss of growth control. the tsgi253-infected cells were similar to tsgi251-infected cells except th ... | 1981 | 6270240 |
| src genes of ten rous sarcoma virus strains, including two reportedly transduced from the cell, are completely allelic; putative markers of transduction are not detected. | the src genes of different rous sarcoma virus (rsv) strains have been reported to be highly conserved by some investigators using rna-cdna hybridization, whereas others using oligonucleotide, peptide, and serological analyses have judged src genes to be variable in 30 to 50% of the respective markers. moreover, distinctive src oligonucleotides and peptides of so-called recovered rsvs (rrsv's) whose src genes were reported to be experimentally transduced from the cell are thought to represent spe ... | 1981 | 6270350 |
| a rous sarcoma virus provirus is flanked by short direct repeats of a cellular dna sequence present in only one copy prior to integration. | the rous sarcoma virus (rsv)-transformed rat cell line rsv-nrk-2 contains a single complete rsv provirus. we have obtained recombinant lambda clones that contain both ends of the rsv provirus and the flanking rat sequences. the provirus is integrated in unique dna and is present in only one of the two homologous chromosomes. the rat sequences into which the rsv provirus integrated were also cloned from the rsv-nrk-2 cell line. the sequences of the regions involved in the recombination event have ... | 1981 | 6270669 |
| biological activity of cloned retroviral dna in microinjected cells. | avian retroviral dna molecules that had been cloned from infected cells by using recombinant dna techniques were microinjected into either uninfected chicken embryo fibroblasts (cef) or cef transformed by the envelope glycoprotein-deficient bryan strain of rous sarcoma virus [rsv(--)cells]. retroviral dna injected into rsv(--) cells directed transcription of envelope mrna, which was then able to complement the rsv(--) env deficiency and promote the production of infectious transforming virus. th ... | 1981 | 6270676 |
| continuous production of rous sarcoma virus free of transformation defective virus in clones of established rsv-transformed quail cells. | 1981 | 6270893 | |
| [acute respiratory syndromes caused by viruses in a pediatric department. clinical and epidemiological studies of a series of cases admitted in the period from february to may, 1979]. | in the period between february and may 1979, in concomitance with a sharp increase in admittance to the pediatric division of the parma general hospital for acute respiratory infections, we carried out a virologic and serologic investigation on hospitalized children aged 21 days-12 years. the investigation was carried out on 137 patients with respiratory diseases: 33 with bronchiolitis, which occurred mainly (32/33) between february and march in children that were prevalently (30/33) in the firs ... | 1981 | 6271082 |
| evidence that viral transforming gene products and epidermal growth factor stimulate phosphorylation of the same cellular protein with similar specificity. | treatment of a-431 human epidermoid carcinoma cells with epidermal growth factor (egf) was shown to enhance the phosphorylation of a mr = 34,000 protein. because the phosphorylation of an analogous protein is enhanced in various cell lines transformed by rous sarcoma virus (rsv) (erikson, e., and erikson, r. l. (1980) cell 21, 829-836), we characterized the phosphorylation of the a-431 mr = 34,000 protein under these two conditions in order to determine whether there are common pathways between ... | 1981 | 6271744 |
| tropomyosin is decreased in transformed cells. | the steady-state level and synthesis of a pair of polypeptides of mr 33,000 and 35,000 in chicken embryo fibroblasts (cef) transformed by rous sarcoma virus (rsv) are significantly decreased relative to normal cef; however, the decrease is more pronounced in the case of the mr 35,000 polypeptide. these polypeptides have been identified as the alpha and beta subunits of cef tropomyosin by selective staining with tropomyosin antibody, two-dimensional gel electrophoresis, partial peptide analysis, ... | 1981 | 6272310 |
| [incorporation of influenza virus antigens into the envelope of the avian oncornavirus]. | the mixture of influenza virus and pseudotype of rous sarcoma virus--rsv (pab-a) grown in chick embryos or cell culture of chick fibroblasts produces a progeny which can be partially neutralized by a heterologous immune serum. the fraction of viral particles, the transformation activity of which is susceptible to suppression by both homologous anti-rsv (pab-a) and heterologous serum, immune to influenza virus, amounts to approximately 20%. after passivation, these particles lose this property wh ... | 1981 | 6272489 |
| [biological properties of the rous sarcoma virus isolated from transformed hamster cells]. | rous sarcoma virus (rsv) isolated from virogenic transformed hamster cells differed from the original schmidt-ruppin strain used to inoculate hamster embryo fibroblasts in the capacity to effectively transform mammalian cells, to multiply in these cells, in the reduced reproductive activity in chicken cells. these altered properties were relatively stable since they were retained in the first virus passages in chickens. | 1981 | 6272496 |
| patterns of shedding of myxoviruses and paramyxoviruses in children. | in the houston family study, young children were cultured for virus weekly or biweekly and during acute respiratory illnesses. the interval between the onset of illness and positive culture was examined for 179 infections during 1975-1979. in week 1 after onset, 73%, 73%, and 66% of cultures were positive for influenza a virus, respiratory syncytial virus (rsv), and parainfluenza virus type 3, respectively. pooled data from influenza b virus infections in 1977 and 1980 showed that 73% of culture ... | 1981 | 6273473 |
| the role of nk cells in tumor growth assessed by induction of their suppressor cells in japanese quails. | in japanese quails treated with chicken amniotic fluid (chamf) which had been previously shown to induce suppressor cells to natural killer (nk) cells, tumors appeared with shortened incubation periods after inoculation with schmidt-ruppin strain of rous sarcoma virus (sr-rsv) compared with untreated quails. the tumors in chamf-treated quails subsequently grew in a similar pattern to those in untreated quails, whereas by challenging with a lower dose of the virus, enhanced tumor growth was obser ... | 1981 | 6273620 |
| inhibition of plasminogen activator release from transformed chicken fibroblasts by a protease inhibitor. | chicken embryo fibroblasts (cef) transformed by rous sarcoma virus (rsv) exhibit increases in both a cell-associated and a secreted form of plasminogen activator (pa). the mechanism whereby the membrane-bound, cell-associated form of pa is processed to an extracellular, soluble form has been examined in cultures of chicken fibroblasts transformed by a temperature-sensitive mutant of rsv. we report that chymostatin, a protease inhibitor of limited specificity, inhibits the release of pa from tsrs ... | 1981 | 6276025 |
| host age and major histocompatibility genotype influence on rous sarcoma regression in chickens. | the influence of host age and b (major histocompatibility complex) genotype on the fate of rous sarcoma virus (rsv)-induced tumors was investigated. white leghorn lines 61 and 151, developed at the regional poultry research laboratory (rprl) at east lansing, mi, and their crosses (f3 to f5) segregating for the b genotype were used. preliminary experiments with noninbred white leghorns showed that chickens rsv-inoculated at 4 weeks of age had a significantly lower incidence of tumor regression th ... | 1981 | 6276876 |
| [gliomas induced in mammals by rous sarcoma virus (rsv) (author's transl)]. | studies concerning the induction of gliomas in a variety of animal species by an oncogenic avian virus (rous sarcoma virus) were presented. experimental conditions (age of inoculation, doses of virus) were reviewed. preliminary attempts to localize viral antigens in the tumors in vivo using labelled antibodies were discussed. | 1981 | 6278340 |
| [comparative ultrastructure of human gliomas and experimental gliomas induced by rous sarcoma virus (rsv) (author's transl)]. | a brief review of earlier results concerning the ultrastructure of 20 gliomas induced by intracerebral inoculation of rous sarcoma virus in the dog emphasizes the similarity of certain canine and human histological types. since no sign of the viral induction is recognizable for certain in the experimental tumors and since the large size of the animal authorizes the use of the same radiological detection techniques as in man these viral induced tumors represent a remarkable experimental model. | 1981 | 6278341 |
| expression of neuronal markers in chick and quail embryo neuroretina cultures infected with rous sarcoma virus. | cultures of neuroretina (nr) cells from 7-day chick and quail embryos were infected with ts ny-68, a thermosensitive mutant of rous sarcoma virus (rsv) which transformed nr cells at 36 degrees c. the following differentiation markers for neurones were studied: tetanus toxin-binding sites at the cell surfaces, presence of synapses, and the specific activity of the enzymes choline acetyltransferase (cat) and glutamic acid decarboxylase (gad). appearance of synapses and expression of cat were simil ... | 1982 | 6279316 |
| concurrent outbreaks of rhinovirus and respiratory syncytial virus in an intensive care nursery: epidemiology and associated risk factors. | an outbreak of viral respiratory disease occurred in eight infants in a neonatal intensive care unit during the 1980 winter respiratory season. four infections with respiratory syncytial virus and four infections with rhinovirus were identified. epidemiologic investigation revealed that viral respiratory infection was significantly associated with intubation with orotracheal tubes (p = 0.001), with the presence of both a nasal feeding tube plus an orotracheal tube together (p = 0.007), and with ... | 1982 | 6279812 |
| [molecular biology criteria for functioning of the genome of rous sarcoma virus in transformed rat xc cells]. | integration, transcription and translation of rous sarcoma virus (rsv) genome was analyzed in transformed rat fibrosarcoma xc cells (non-virus producing). about ten copies of rsv genome were integrated into the host cell genome. different types of viral rna were identified in the cytoplasmic fraction whose sedimentation values were nearly the same as for rsv-specific rna in virus-producing chicken cells. these rna were translated in polysomes and directed synthesis of gag, env and src proteins. ... | 1982 | 6280033 |
| epidermal growth factor and insulin cause normal chicken heart mesenchymal cells to proliferate like their rous sarcoma virus-infected counterparts. | normal chicken heart mesenchymal cells at low culture density are proliferatively quiescent in a physiological culture medium containing heparinized, heat-inactivated, chicken plasma at 10%. rous sarcoma virus-infected chicken heart mesenchymal cells, on the other hand, proliferate maximally in this same medium, undergoing a 60-fold increase in cell number during 4 days of exponential growth. when normal heart mesenchymal cells are cultured for 4 days in the presence of epidermal growth factor a ... | 1982 | 6280169 |