| bacterial coinfection in children hospitalized with respiratory syncytial virus infections. | clinical and bacterial findings were prospectively studied in 90 children hospitalized because of middle or lower respiratory tract infection caused by respiratory syncytial virus (rsv) during a surveillance period of 12 months. the results were compared with those of rsv-negative children hospitalized with identical indications during the 3 peak months of the rsv epidemic (n = 91) or for the 3 months after the outbreak (n = 99). a high frequency of pneumonia and acute otitis media were found in ... | 1989 | 2812913 |
| respiratory syncytial virus infections in children admitted to the intensive care unit. | during the winter of 1986-1987, 64 children with respiratory syncytial virus (rsv) infection were admitted to our hospital. the diagnosis was made by direct immunofluorescent antibody technique. twenty-three children (36%) needed intensive care treatment. nearly 11 (52%) had a preexisting disease state, identified as a risk factor i.e., prematurity (n = 8), bronchopulmonary dysplasia (n = 2), congenital heart disease (n = 1). twelve patients (50%) were intubated and ventilated. conditions for in ... | 1989 | 2812976 |
| elevated phosphatidylinositol kinase activity in rous sarcoma virus-transformed cells. lack of evidence for enzyme translocation. | phosphatidylinositol kinase (e.c. 2.7.1.67) activity of rat fibroblasts transformed by rous sarcoma virus (rsv) was measured and compared with immunoprecipitated protein tyrosine kinase activity associated with pp60v-src. both enzyme activities were elevated in the particulate fractions from wild-type rsv-transformed cells and cells transformed by a temperature-sensitive mutant of rsv when grown at the permissive temperature. the presence of the non-ionic detergent nonidet p-40 in the phosphatid ... | 1987 | 2822141 |
| growth inhibitors in serum, platelets, and normal and malignant tissues. | the non-malignant epithelial cell line from buffalo rat liver (brl) and its malignant transformant obtained by rous sarcoma virus infection (rsv-brl) were used as the indicators. a survey was made in animals for growth inhibitors which could inhibit the growth of brl, but not the growth of rsv-brl in culture, under the consideration that the loss of the sensitivity to such inhibitors might be the most dominant cause for acquisition of tumorigenicity. from human platelets, a growth inhibitor was ... | 1987 | 2823546 |
| the methylation state of the proviruses in avian sarcoma virus transformed chick and rat cells. | the endogenous viruses in the avian cells are not completely methylated, nor are the schmidt-ruppin rsv-d (srd) proviruses in the infected cells completely unmethylated. avian sarcoma proviruses integrated in rat transformed cloned cells are heavily methylated. in these cells, a region in the 3' end of the env gene is unmethylated in all the src-containing proviruses but not in the transformed defective (td) proviruses. a possible role for the hypomethylation of the 3' end of the env region is p ... | 1987 | 2823897 |
| surveillance of respiratory viral infections by rapid immunofluorescence diagnosis, with emphasis on virus interference. | during the 7-year period from september 1978 to august 1985, smear specimens of nasopharyngeal secretions from 3132 patients mainly hospitalized children, taken in different regions in norway, were examined for respiratory viruses by the rapid immunofluorescence (if) technique. a positive diagnosis for respiratory syncytial virus (rsv), parainfluenza virus type 1, 2 and 3 or influenza a and b virus was made for 896 patients (29%). the greatest prevalence for all these viruses was observed during ... | 1987 | 2824225 |
| [expression of a cross-reactive antigen on the surface of human epidermoid carcinomas overproducing egf-receptor shared with rsv-induced tumors]. | analysis based on the complement-dependent cytotoxicity (cdc) assays using syngeneic antiserum against a rous sarcoma virus(rsv)-induced mouse tumor(csa1m) showed that a cross-reactive antigen with a common tumor-associated cell surface antigen(tasa) of rsv-induced mouse tumors was shared with two human tumors a431 and mda-468 overexpressing epidermal growth factor receptor(egfr). the tasa, however, was not expressed on four human choriocarcinomas, a human lung cancer a2182, and human embryo fib ... | 1987 | 2824311 |
| [representation of the leader region of rous sarcoma virus genome rna in double-stranded rna produced in virus-transformed cells]. | restriction fragments of recombinant plasmids containing a proviral sequence of rous sarcoma virus (rsv) were southern hybridized with double-stranded (ds) rna isolated from the cells transformed with rsv. hybridization data show that the major subpopulation of dsrna molecules is homologous to the 5'-end region of the viral genome including the leader sequence. we have analysed the rnas of rsv-transformed cells by the northern procedure hybridizing them with the proviral fragment containing doub ... | 1987 | 2824985 |
| genetic associations of body weight and immune response with the major histocompatibility complex in white leghorn chicks. | survival, body weight, and humoral immune response to sheep red blood cells (srbc) were measured in 256 chicks of the iowa state university s1 leghorn line. the chicks were produced from breeders selected for serological ea-b blood type (b1 or b19), high or low humoral immune response to the amino acid polymer, glutamic acid-alanine-tyrosine (ir-gat), and response to rous sarcoma virus-induced (rsv) tumors (progression or regression). chicks were hatched from sublines representing all eight trip ... | 1987 | 2825154 |
| epidemiology of viral infections in singapore. | as singapore is a densely populated island, and also a major air and sea port, the importation and dissemination of viral infections is facilitated. respiratory viral infections have the highest prevalence rates, influenza and respiratory syncytial virus (rsv) being the most important ones. seasonal variation occurs with influenza, rsv and parainfluenza virus type 1 infections. the age distribution and clinical picture associated with infections due to the various respiratory viruses are similar ... | 1987 | 2825585 |
| reduced expression of mhc class i antigens in chicken fibroblasts transformed by rous sarcoma virus. | monoclonal monomorphic as well as polyclonal antibodies against h-b class i (b-f) antigen were used to evaluate the expression of these molecules on normal and rsv-transformed chick embryo fibroblasts. the results indicate that chicken fibroblasts transformed in vitro by the schmidt-ruppin strain rous sarcoma virus of subgroup b (sr-rsv-b) present reduced h-b class i antigen expression as compared to uninfected cells of the same inbred strain. this quantitative reduction was observed at the cell ... | 1987 | 2826262 |
| specific nuclear proteins interact with the rous sarcoma virus internal enhancer and share a common element with the enhancer located in the long terminal repeat of the virus. | we have documented that the rous sarcoma virus (rsv) internal enhancer functions in the nontransformed baby hamster kidney (bhk) cell line. the sequences within this region were assayed for their ability to bind to specific factors present in bhk nuclear extracts using the gel retardation assay and dnase i footprinting. at least two sequences within the internal enhancer which can specifically bind nuclear factors in vitro have been identified. these regions are located between nucleotides 813-8 ... | 1987 | 2827114 |
| pulmonary infections with respiratory syncytial virus and the parainfluenza viruses. | respiratory syncytial virus (rsv) and the parainfluenza viruses (pivs) are the most important causes of acute lower respiratory illness (lri) in infants and children under 6 years of age. these enveloped viruses are members of the paramyxovirus family. they infect cells in the epithelium lining the trachea and intrapulmonary airways, and cause croup, bronchitis, bronchiolitis, and bronchopneumonia. rsv causes annual midwinter to early spring outbreaks of respiratory disease in temperate climates ... | 1987 | 2827280 |
| identification of sequences in the long terminal repeat of avian sarcoma virus required for efficient transcription. | two different vectors, ltr-neo-ltr and ltr-cat-ltr, were constructed and deletions were introduced in the upstream ltr at -299 and at -140. these deletion mutants were introduced into qt6 cells under transient expression conditions, and the levels of transcription were monitored by dot blot hybridization or by cat assays. the results indicate that the nucleotides between -208 and -201 and between -141 and -119 in the u3 region of rsv ltr are required for efficient transcription. | 1988 | 2827383 |
| purification and properties of a non-histone chromatin protein with a molecular weight of 38,000 daltons specific for transformed rat cells. | non-histone chromatin proteins prepared from a normal rat cell line (no. 7) and the cells transformed with rous sarcoma virus (rsv) (s7-1) were compared by means of reverse-phase high performance liquid chromatography (reverse-phase hplc), followed by sds-polyacrylamide gel electrophoresis (sds-page). the results revealed that several proteins were specifically present in the transformed cell chromatin. a specific non-histone chromatin protein with a molecular weight of 38,000 daltons, 38k prote ... | 1987 | 2827654 |
| transformation of rat liver cell line by rous sarcoma virus causes loss of cell surface fibronectin, accompanied with secretion of metallo-proteinase that preferentially digests the fibronectin. | an epithelial cell line derived from the liver of a normal buffalo rat (brl) was transformed by rous sarcoma virus (rsv). the rsv-transformed cells were separated into five clones (rsv-brl1 through 5), which were morphologically different. rsv-brl cells exhibited the following characteristics distinct from those of brl cells: tumorigenicity, irregular cell arrangement, loose intercellular junction, growth in soft agar (anchorage-independent growth) except for rsv-brl3 and 5, and loss of cell sur ... | 1987 | 2828345 |
| prenatal lethality in a transgenic mouse line is the result of a chromosomal translocation. | we have produced a line of transgenic mice that is characterized by prenatal lethality. these mice bear a chimeric plasmid containing the long terminal repeat of the rous sarcoma virus linked to the coding region of the chloramphenicol acetyltransferase gene (prsv-cat). mice heterozygous for the prsv-cat integration site are semisterile, producing litters approximately equal to 40% of the average size when crossed to normal mice. approximately 50% of the progeny from such a cross bear the prsv-c ... | 1988 | 2829218 |
| restriction analysis of additional "non-producing" cell clones obtained after transformation of japanese quail fibroblasts with viruses rescued from cryptovirogenic h-19 cells. | the proviral structure of two transforming viruses rescued from cryptovirogenic h-19 hamster cells harbouring the ltr, v-src, ltr proviral structure was analysed by restriction mapping. it was established that the rescued g8 virus keeps the same restriction pattern as that observed in the cryptic h-19 provirus and that it is integrated into the cell genome at a different position characteristic of each "non-producing" (np) cell clone. in these features it corresponds to the previously described ... | 1987 | 2830149 |
| polyphosphoinositide metabolism is rapidly stimulated by activation of a temperature-sensitive mutant of rous sarcoma virus in rat fibroblasts. | we have examined polyphosphoinositide turnover in a rat-1 fibroblast line infected with a temperature-sensitive mutant (ts la24) of the rous sarcoma virus (rsv). when ts la24-infected cells are shifted from the non-permissive to the permissive temperature, a rapid and sustained activation of phospholipase c (plc) is observed. normal and wild-type rsv-infected rat-1 cells do not show any plc activation upon temperature shiftdown. pre-treatment of ts la24-infected fibroblasts with tetrodotoxin (a ... | 1987 | 2830581 |
| high chemotactic motility and growth in hard agar of a variant of rsv-transformed fibroblasts are lost in late passages. | cloning efficiency in hard agar (0.6%) and high chemotactic migration toward fibroblast conditioned medium have been shown to characterize metastatic tumor cells. we studied growth in 0.6% agar and chemotaxis of two lines of rous sarcoma virus-transformed balb/c3t3 cells, b77/3t3 (low metastatic) and aa12 (high metastatic), and compared them to their non-transformed counterpart, in order to verify whether these properties were maintained during several subcultivations. cells were cryopreserved a ... | 1988 | 2832985 |
| mechanism of target cell lysis by cytotoxic t lymphocytes (ctl) employing rsv-induced h-2 congenic and recombinant mouse tumor cells: demonstration of soluble mediators released from h-2-restricted ctl clones. | the secretion and the specificity of cytotoxic mediators from h-2-restricted cytotoxic t lymphocytes (ctl) were examined using non-virus-producing target tumor cells induced by the schmidt-ruppin strain of rous sarcoma virus (sr-rsv) in b10 congenic and recombinant mice. by using rat concanavalin a supernatant, two h-2-restricted ctl clones were established from cytotoxic effector cells of b10.a(5r) mice primed with sr-rsv-induced syngeneic tumor cell-free supernatants from the h-2-restricted ct ... | 1988 | 2833355 |
| evidence for positive and negative regulation in the promoter of the chicken delta 1-crystallin gene. | we investigated the role of sequences flanking the transcription initiation site of the delta 1-crystallin gene in transient transfection assays of primary embryonic chicken lens epithelial cells or fibroblasts. varying lengths of the 5' flanking sequence of the delta 1-crystallin gene (containing some untranslated sequence from exon 1) were fused to the bacterial chloramphenicol acetyltransferase (cat) gene in the psvocat plasmid. a plasmid carrying the bacterial beta-galactosidase gene driven ... | 1988 | 2834246 |
| detection of respiratory syncytial virus and rotavirus by enhanced chemiluminescence enzyme-linked immunosorbent assay. | the horseradish peroxidase-catalyzed oxidation of luminol was used in a chemiluminescence avidin-biotin enzyme-linked immunosorbent assay (cl-abe) to detect respiratory syncytial virus (rsv) and rotavirus (rov). this cl-abe was carried out in a new apparatus constructed for the photographic registration of the light emission produced. when measured in a spectrophotometer, the light emission produced by the oxidation of luminol showed a peak emission at 425 nm. the chemiluminescence output reache ... | 1988 | 2835387 |
| tissue tropism and temporal expression of rous sarcoma virus in embryonic avian limb in ovo. | embryonic avian tissue is resistant to the transforming potential of rous sarcoma virus (rsv) in ovo. analysis of the pattern of host-viral interactions in the first semester of chick development has demonstrated that rsv is first expressed in a limited population of muscle precursor cells and proceeds to spread throughout the developing dorsal and ventral limb musculature. the number of non-muscle cells participating in the infection is initially low but gradually increases as development conti ... | 1987 | 2835735 |
| participation of cytoskeletal intermediate filaments in the infectious cycle of human respiratory syncytial virus (rsv). | rsv infection of hep-2 or hela cells leads to biochemical and morphological changes of cytoskeletal intermediate filaments (if). thus, human cytokeratin 18 is modified to generate a more acidic polypeptide of slightly larger apparent molecular weight. in addition, the amounts of vimentin and other cytokeratins are reduced, probably as a consequence of proteolytic degradation. these changes are reflected in a decrease of immunofluorescence with specific antibodies in rsv-induced syncytia and a mo ... | 1988 | 2837016 |
| live viral vaccines for respiratory and enteric tract diseases. | in its programme for accelerated development of vaccines for viral respiratory and enteric tract diseases the who has assigned a very high priority to respiratory syncytial virus (rsv), parainfluenza viruses and rotaviruses. there is also some interest in alternative approaches to immunization against influenza viruses because of the failure of inactivated vaccines to provide complete and reasonably durable immunity. current attempts to develop satisfactorily attenuated viruses for use in preven ... | 1988 | 2838984 |
| viral products in cells infected with vesicular stomatitis virus and superinfected with rous sarcoma virus. | in cells infected with vesicular stomatitis virus (vsv) ts 1026 and superinfected with rous sarcoma virus (rsv) synthesis of vsrc mrna and rsv env mrna decreases. in these cells post-translational processing of rsv precursor proteins is impaired and small amounts of vsv antigens are detected. | 1988 | 2839128 |
| simultaneous infection with respiratory syncytial virus and other respiratory pathogens. | the presentation and subsequent course of respiratory syncytial virus (rsv) bronchiolitis may be atypical and unusually severe when simultaneous infection due to other pathogenic agents is present. during the past two years, nine of the 189 pediatric patients hospitalized with documented rsv infection were found to have the following simultaneous isolates from initial respiratory tract specimens: four adenovirus, four pneumococcus, one cytomegalovirus, and one pneumocystis carinii. noted complic ... | 1988 | 2839976 |
| mycoplasma pneumoniae and other pathogens in the aetiology of lower respiratory tract infections among japanese children. | the causes of lower respiratory tract infections in 1544 children attending a japanese hospital over a period of 7 years were investigated. both cultivation and two serological techniques were used to detect mycoplasma pneumoniae whereas viral involvement was investigated only by serology. pathogens were identified in 52% of 1175 patients with pneumonia and 36% of 369 patients without pneumonia. mycoplasma pneumoniae infection was specifically diagnosed in 414 (26.8%) of the 1544 patients. respi ... | 1988 | 2840466 |
| transcription of proto-oncogenes in rous sarcoma virus infected and transformed chicken embryo cells. | to evaluate an effect of infection by rsv on the transcriptional activity of proto-oncogenes, we tested 19 cellular oncogenes and the beta-actin gene performing "nuclear run on transcription assays" using nuclei isolated from rsv infected or transformed chick embryo cells (cec). a drastic increase in the transcriptional activity of the c-fgr proto-oncogene and a slight increase of c-fos and c-myc could be observed in uninfected compared to rsv infected cec. to distinguish between infection- and ... | 1988 | 2840872 |
| determination of the mutation rate of a retrovirus. | the mutation rate of rous sarcoma virus (rsv) was measured. progeny descended from a single virion were collected after one replication cycle, and seven regions of the genome were analyzed for mutations by denaturing-gradient gel electrophoresis. in all, 65,250 nucleotides were screened, yielding nine mutations, and the rsv mutation rate was calculated as 1.4 x 10(-4) mutations per nucleotide per replication cycle. these results indicate that rsv is an extremely mutable virus. we speculate that ... | 1988 | 2841464 |
| 78-kilodalton glucose-regulated protein is induced in rous sarcoma virus-transformed cells independently of glucose deprivation. | to identify mrnas with altered expression in rous sarcoma virus (rsv)-transformed cells, we screened a chicken embryo fibroblast (cef) cdna library by differential hybridization. one clone, designated r1h, showed markedly elevated mrna expression in rsv-transformed cells. nucleotide sequence analysis indicated that r1h mrna encodes 78-kilodalton glucose-regulated protein (grp78). chicken grp78 was found to be very highly conserved in comparison with rat grp78 (96% identity between chicken and ra ... | 1988 | 2841586 |
| transfer and expression of the bacterial npt-ii gene in chick embryos using a schmidt-ruppin retrovirus vector. | in an effort to introduce foreign genes into chickens, the bacterial neomycin phosphotransferase (npt-ii) gene was cloned into an infectious avian retroviral vector derived from the schmidt-ruppin a strain of rsv. the npt-ii gene was stable in the vector during passage in vitro and infected cells were resistant to g418. fertilized chicken embryos were inoculated with the recombinant virus on day 0 and screened on day 20 for the npt-ii gene in blood cell dna. approximately 12% of the embryos were ... | 1988 | 2842731 |
| contribution of rhinoviruses to respiratory viral infections in childhood: a prospective study in a mainly hospitalized infant population. | a prospective study was carried out to investigate the contribution of rhinoviruses to respiratory viral infections in children and to investigate the influence of age, passive smoking, and educational level of the head of the family on the clinical course of viral respiratory disease. nasopharyngeal aspirates from 519 infants (90.8% inpatients, 9.2% outpatients) were screened for the presence of rhinoviruses, respiratory syncytial virus (rsv), adenoviruses, parainfluenza virus types 1, 2, 3, in ... | 1988 | 2844986 |
| current approaches to the development of vaccines effective against parainfluenza and respiratory syncytial viruses. | vaccines against parainfluenza (piv) and respiratory syncytial viruses (rsv) that are currently being developed include both live and subunit vaccines. candidate live piv vaccines that have been found to be attenuated and efficacious in rodents or primate models are (1) cold-adapted, temperature-sensitive mutants of piv-type 3 that have been serially passaged at low temperature (20 degrees c) in simian kidney tissue culture; (2) protease-activation mutants (piv-1-sendai), which have mutations th ... | 1988 | 2845680 |
| signals for ribosomal frameshifting in the rous sarcoma virus gag-pol region. | the gag-pol protein of rous sarcoma virus (rsv), the precursor to the enzymes responsible for reverse transcription and integration, is expressed from two genes that lie in different translational reading frames by ribosomal frameshifting. here, we localize the site of frameshifting and show that the frameshifting reaction is mediated by slippage of two adjacent trnas by a single nucleotide in the 5' direction. the gag terminator, which immediately follows the frameshift site, is not required fo ... | 1988 | 2846182 |
| resistance of chickens to rous sarcoma virus challenge following immunization with a recombinant avian leukosis virus. | an attenuated recombinant avian leukosis virus (alv) produced by recombinant dna techniques was examined for its ability to provide resistance to rous sarcoma virus (rsv) challenge. specific-pathogen-free chicken embryos (18-day incubation) and hatched chicks inoculated with recombinant alv produced significantly smaller tumors than sham-inoculated controls upon challenge with rsv 2 weeks postinoculation; inoculation with rav-1 produced similar results. specific-pathogen-free hens inoculated wit ... | 1988 | 2848482 |
| the introduction of biologically active foreign genes into human respiratory epithelial cells using electroporation. | a simple method for introducing genes into respiratory epithelial cells would assist molecular studies of a variety of pulmonary disorders. several different techniques for introducing foreign dna into cells have been described but have either not been useful for respiratory epithelial cells or are difficult and cumbersome to perform. electroporation is a simple technique that consists of exposing a cell-dna suspension to an electric shock. although it has been used to introduce genes into a var ... | 1988 | 2849346 |
| an analysis of the response of recombinant congenic lines of chickens to rsv challenge provides evidence for further complexity of the genetic structure of the chicken mhc (b). | we found that cb (b12/b12) and cb.r1 (b12r1/b12r1) congenic chicken lines differing from each other only in the b-g region of the mhc(b), although both of them could be characterized as regressors of rous sarcomas induced by pr-c and bh-c, are distinguishable in their response to the challenge with these two viruses by means of some parameters of tumour growth. this points further to the concept of functional and structural complexity of the b-g region. both cb and cb.r1 lines are highly suscept ... | 1988 | 2849569 |
| anti-rous sarcoma response of major histocompatibility (b) complex haplotypes b23, b24 and b30. | responses to rous sarcoma virus (rsv) induced tumours were studied in unh 105, a non-inbred line of new hampshire chickens. six single male matings encompassing a total of 50 dams produced 345 progeny which segregated for b complex genotypes b23/b23, b23/b24, b23/b30, b24/b24, b24/b30 and b30/b30. six-week-old chicks were wingweb inoculated with a pseudotype of bryan high titre rous sarcoma virus, bh rsv (rav-1). tumours were scored for size six times over a 10-week period post-inoculation. each ... | 1988 | 2849889 |
| tsh stimulates the activity of the c-fos promoter in frtl5 rat thyroid cells. | c-fos promoter activity was examined in frtl5 rat thyroid cells transiently transfected with a chimeric gene containing the c-fos promoter region linked upstream of the receptor gene chloroamphenicol acetyl transferase (cat). thyroid-stimulating hormone (tsh) stimulation of transfected cells increased cat activity 2- to 3-fold. tsh did not stimulate cat activity driven by the rous sarcoma virus (rsv) promoter. both forskolin and 8-br-cyclic amp also stimulated cat activity, and were not additive ... | 1988 | 2850250 |
| peptides as potential virus inhibitors. synthesis and bioassay of five respiratory syncytial virus peptide analogs with antimeasles activity. | five carbobenzoxylated and d-amino acid containing-peptide analogs of the respiratory syncytial virus (rsv) f1 glycoprotein amino terminus were chemically synthesized by solution and fmoc-solid phase peptide synthesis methods. several of these peptides, ranging from 3 to 6 residues in length, raised the bilayer to hexagonal phase transition temperature of dielaidoylphosphatidylethanolamine. none of these peptides were specific inhibitors of rsv or herpes simplex virus infection. two of the serie ... | 1988 | 2850279 |
| regulation of rous sarcoma virus rna splicing and stability. | only a fraction of retroviral primary transcripts are spliced to subgenomic mrnas; the unspliced transcripts are transported to the cytoplasm for packaging into virions and for translation of the gag and pol genes. we identified cis-acting sequences within the gag gene of rous sarcoma virus (rsv) which negatively regulate splicing in vivo. mutations were generated downstream of the splice donor (base 397) in the intron of a proviral clone of rsv. deletion of bases 708 to 800 or 874 to 987 result ... | 1988 | 2850470 |
| structural and functional motifs of the rous sarcoma virus src protein. | site-directed mutagenesis techniques have been utilized to define important structural and functional domains within the rsv src gene product, pp60src. deletion mutations within the amino terminal one-half of the src gene which impinge upon a region of the src protein delineated by amino acid residues 143 to 169 yielded transformation defective viruses. src proteins encoded by such rsv mutants exhibited diminished tyrosine protein kinase activity in vitro and only slightly reduced levels of in v ... | 1986 | 2851527 |
| brdu-induced changes in the provirus of pr-rsv in mammalian cells. | previously we demonstrated differences in the organization and methylation pattern of integrated rous sarcoma proviral sequences in helper-dependent virogenic rat twerc cells. in the present study we attempted to induce changes in the integrated viral genome of twerc cells using 5-bromodeoxyuridine (brdu). four clones (a, b, c, and f) derived from the parental cell line were treated for 10 months with different concentrations of brdu. restriction enzyme analysis of the parental cell line and its ... | 1988 | 2851743 |
| antigen detection in the diagnosis of viral infections. | the value of viral antigen detection from nasopharyngeal secretion (nps) by enzyme immunoassay (eia) in everyday clinical practice was evaluated in 570 children hospitalized because of infections. nps-eia gave a positive result in 32% of all cases. virus isolation was positive in the nps in 25%, virus isolation in stool samples in 14%, and virus serology in 28% of the cases. nps-eia was superior for detecting adenovirus, respiratory syncytial (rs) and parainfluenza viruses. in a series of 124 pa ... | 1988 | 2851878 |
| concomitant immunity leads to retardation or acceleration of the growth of rous sarcomas in genetically resistant or susceptible inbred lines of chickens. | we report results on the age-dependent effect of the b (mhc) genotype on resistance to the growth of a second rsv tumour in chickens from highly inbred lines genetically resistant or susceptible to progressive growth of primary rsv-induced tumours. furthermore, the second inoculation of rsv caused either accelerated or retarded growth of the primary tumours induced by the same virus. these two types of response to a second challenge with rsv were controlled by alleles of the chicken major histoc ... | 1986 | 2852125 |
| virus dilution affects the anti-rous sarcoma response of progressor but not regressor major histocompatibility (b) complex genotypes. | responses to tumors induced by three dilutions of rous sarcoma virus (rsv) were studied in unh 105, a noninbred line of new hampshire chickens. single-male matings produced progeny of three b genotypes: b23/b23 (tumor regressor) and b23/b24 and b24/b24 (tumor progressors). a total of 223 6-wk-old chicks were wingweb inoculated with one of three dilutions (10(-3), 4 x 10(-3), and 10(-4)) of a pseudotype of bryan high titer rsv designated as bh rsv (rav-1). a tumor profile index (tpi), an indicato ... | 1988 | 2853337 |
| rice stripe virus: prototype of a new group of viruses that replicate in plants and insects. | the unusual filamentous particles of rice stripe virus contain four species of single-stranded rna. similar filamentous particles are common in other planthopper-borne viruses of the rice stripe virus group, of which a type virus, rice stripe virus, is reviewed. | 1986 | 2856619 |
| cytotoxic lymphocytes in the lungs of mice infected with respiratory syncytial virus. | mice infected with respiratory syncytial virus (rsv) developed cytotoxic lymphocytes in the lungs, which lysed rsv-infected, but not uninfected cells. cytotoxic activity was greatest 7 to 9 days after infection, was virus-specific, mhc-restricted and abolished by treatment of lymphocytes with anti-thy 1.2 or with anti-lyt 2.2 sera and complement. there was a close temporal relationship between the appearance of these cytotoxic lymphocytes in the lung and clearance of virus. in contrast, rsv pers ... | 1985 | 2866227 |
| simultaneous infection with bordetella pertussis and respiratory syncytial virus in hospitalized children. | we compared three groups of hospitalized children with bordetella pertussis infection, respiratory syncytial virus (rsv) infection and dual b. pertussis/rsv infections in an effort to establish clinical and laboratory criteria by which to distinguish children with dual infections from children infected with either organism alone. the groups were compared for admission laboratory data, history of present illness, perinatal history and immunization history. children with pertussis were more likely ... | 1986 | 2876415 |
| cell-mediated cytotoxic response to respiratory syncytial virus in infants with bronchiolitis. | a cell-mediated cytotoxic response to respiratory syncytial (rsv) was demonstrated in the peripheral blood of 4 of 22 infants with acute bronchiolitis. these 4 infants were aged 3 weeks to 3 months. no such response was found in infants older than 4 months. all 4 infants with a positive response had mild infections. | 1987 | 2888988 |
| rapid detection of respiratory syncytial virus in clinical specimens. | results of the direct immunofluorescence (if) test in 152 clinical specimens (throat swabs) were compared with those of respiratory syncytial virus (rsv) isolation. the prevalence of rsv infections in the upper and lower respiratory tract was high especially in infants until 12 months of age. the average rsv isolation rate was 18.42%, whereas the virus antigen detection was positive in 19.74% of cases. the agreement between virus isolation and direct if was 92.1%, the sensitivity of if being 82. ... | 1987 | 2891280 |
| respiratory syncytial virus outbreak on american samoa. evaluation of risk factors. | acute respiratory illness is one of the leading causes of childhood mortality in developing nations. we investigated an increase in hospitalizations of children less than 2 years old for severe lower respiratory tract illness (lri) from october 1986 through december 1986 on the island of american samoa. hospitalization rates were highest in children less than 6 months of age (60 of 1000 compared with 22 of 1000 for those 6 to 11 months of age, and seven of 1000 for those 12 to 24 months of age). ... | 1989 | 2916509 |
| a concurrent epidemic of respiratory syncytial virus and echovirus 7 infections in an intensive care nursery. | we describe concurrent outbreaks of respiratory syncytial virus (rsv) and echovirus 7 (echo 7) infections in a neonatal intensive care unit, including infants who had dual infections. seventy-three infants were identified as having rsv from january through june, 1984. during the same surveillance period echo 7 was cultured from 20 infants, and 6 infants had concurrent rsv and echo 7 and rsv were isolated, but not concurrently. this dual outbreak of rsv and echo 7 infections persisted for months ... | 1989 | 2922234 |
| effect of breast feeding on the development of anti-idiotype antibody response to f glycoprotein of respiratory syncytial virus in infant mice after post-partum maternal immunization. | groups of lactating balb/c mice were immunized in the immediate postpartum period with high doses of mab (ab-1) to the f-glycoprotein (f-gp) of respiratory syncytial virus (rsv). this antibody possessed neutralizing activity against the whole virus. the immune response to f-gp was studied in the breast feeding infant mice of such mothers at regular intervals before and after weaning. all infant mice exhibited anti-f-gp activity in serum, which was detected until 6 wk of age. splenic cells of suc ... | 1989 | 2926142 |
| host cell reactivation of cat-expression vectors as a method to assay for cloned dna-repair genes. | we demonstrate the feasibility of using passive host-cell reactivation of a shuttle-vector prsvcat to detect cloned dna-repair genes. as models, a transient expression vector, prsvdenv, and a positive-selection vector, prsvdenv/svgpt, were constructed containing the t4 coliphage denv gene, coding for an ultraviolet-specific endonuclease, under promotion of the rous sarcoma virus (rsv) long-terminal repeat. cotransfection of one or three copies of prsvdenv per uv-irradiated prsvcat molecule into ... | 1989 | 2927423 |
| respiratory syncytial virus infection of human mononuclear leukocytes in vitro and in vivo. | recurrent infections with respiratory syncytial virus (rsv) have been well documented despite serological evidence of prior exposure of the host and the absence of clear evidence of antigenic variation of the virus. therefore, human mononuclear leukocytes, as well as purified lymphocytes and monocytes-macrophages, were exposed to rsv in vitro and examined for expression of viral antigens by using indirect immunofluorescence with monoclonal antibodies to rsv. rsv infected both human monocytes-mac ... | 1985 | 2931491 |
| helper t cell recognition of respiratory syncytial virus in mice. | in this study we aimed to define the protein and viral subtype specificities of helper th cells to respiratory syncytial virus (rsv). balb/c mice were primed by infection with rsv, or with vaccinia viruses (vv) containing genes encoding several individual rsv proteins. priming for th cell memory was assayed by stimulating spleen cells in vitro with different rsv isolates and measuring rsv-specific interleukin 2 (il-2) release by t cells into supernatants using an il-2-dependent ctll cell line. s ... | 1988 | 2963089 |
| isolation of a line of immortal chicken embryo fibroblasts after transfection with the nuclei of rous sarcoma virus-transformed chinese hamster cells. | secondary cultures of chicken embryo fibroblasts were transfected with purified nuclei from lysed cells of a clonal line of temperature-sensitive rous sarcoma virus (tsrsv)-transformed chinese hamster fibroblasts. after propagation for 3 months an established cell line designated chr32 was obtained in one chicken cell culture. the cells of this line have been propagated so far for 18 months, whereas normal chicken embryo fibroblasts died after 2 months. the established cells were heteroploid wit ... | 1985 | 2981172 |
| coordinate regulation of the levels of type iii and type i collagen mrna in most but not all mouse fibroblasts. | a mouse genomic clone was isolated by cross-hybridization with a dna fragment which codes for the nh2-propeptide of chick alpha1(iii) collagen. the region of cross-hybridization within the mouse clone was localized, its sequence determined, and an exon coding for the nh2-propeptide of mouse alpha1(iii) collagen was identified. this dna fragment hybridizes to an rna species of approximately 5300 nucleotides, slightly larger than the major alpha2(i) collagen rna species. the mouse type iii collage ... | 1985 | 2981217 |
| molecular basis of host range variation in avian retroviruses. | previous genetic analysis has localized the region of the rous sarcoma virus (rsv) env gene responsible for host range specificity to that encoding the middle one-third of gp85. to better understand the host range determinants, the relevant regions of the genomes of infectious molecular clones of the transformation-defective prague strain of rsv, subgroup b (pr-rsv-b) and rous-associated virus 0 (rav-0) (subgroup e) were sequenced and compared with the sequence of pr-rsv-c. this comparative anal ... | 1985 | 2981357 |
| highly specific antibody to rous sarcoma virus src gene product recognizes a novel population of pp60v-src and pp60c-src molecules. | antiserum to the rous sarcoma virus (rsv)-transforming protein, pp60v-src, was produced in rabbits immunized with p60 expressed in escherichia coli. alpha p60 serum immunoprecipitated quantitatively more pp60v-src than did tumor-bearing rabbit (tbr) sera. when rsv-transformed cell lysates were preadsorbed with tbr serum, the remaining lysate contained additional pp60v-src, which was recognized only by reimmunoprecipitation with alpha p60 serum and not by tbr serum. in subcellular fractions of rs ... | 1985 | 2981886 |
| antiviral effect of flavonoids on human viruses. | the effect of several naturally occurring dietary flavonoids including quercetin, naringin, hesperetin, and catechin on the infectivity and replication of herpes simplex virus type 1 (hsv-1), polio-virus type 1, parainfluenza virus type 3 (pf-3), and respiratory syncytial virus (rsv) was studied in vitro in cell culture monolayers employing the technique of viral plaque reduction. quercetin caused a concentration-dependent reduction in the infectivity of each virus. in addition, it reduced intra ... | 1985 | 2981979 |
| a retrovirus-like strategy for expression of a fusion protein encoded by yeast transposon ty1. | eukaryotic transposons such as the ty element of yeast or the copia-like sequences of drosophila show structural and functional similarities to both prokaryotic transposons and retroviral proviruses, but the prokaryotic transposons and retroviral proviruses use markedly different expression strategies which yield products having entirely different functions. to determine the phylogenetic relationship between eukaryotic transposons, prokaryotic transposons and retroviruses, we have sought to iden ... | 1985 | 2982101 |
| transfer of genes into hematopoietic cells using recombinant dna viruses. | the ability of recombinant dna viruses to transfer genes into hematopoietic cells has been explored. a recombinant simian virus 40 (sv40) in which the early region had been replaced with the chloramphenicol acetyltransferase (cat) gene driven by the promoter from rous sarcoma virus (rsv), was constructed. this virus transferred the cat gene more efficiently into mouse and human bone marrow cells and into the k562, mel, and wehi hematopoietic tissue culture cell lines, than the classical calcium ... | 1985 | 2982141 |
| distinctive effects of the viral oncogenes myc, erb, fps, and src on the differentiation program of quail myogenic cells. | the relationship between susceptibility to transformation in vitro by different oncogenes and terminal differentiation was analyzed in embryonic quail myogenic cells. infection with rous sarcoma virus (rsv), fujinami sarcoma virus (fsv), avian erythroblastosis virus (aev), and the avian myelocytomatosis virus mc29 led to rapid and massive transformation. transformed cells had distinctive morphological alterations, increased proliferation rates, and the ability to grow in agar suspension. further ... | 1985 | 2982156 |
| transformation of erythroid cells by rous sarcoma virus (rsv). | rsv transforms several nonhematopoietic cell types and as reported here also has the capacity to transform hematopoietic cells of the erythroid lineage. in vitro, the three rsv isolates tested induced erythroblast-like colonies in infected bone marrow cells that were distinguishable by size and cell arrangement from those induced by avian erythroblastosis virus (aev). also in contrast to aev-transformed erythroblast cultures, isolated cell colonies induced by rsv required complex growth conditio ... | 1985 | 2982235 |
| organization of cytoskeleton and fibronectin matrix in rous sarcoma virus (rsv)-transformed fibroblast lines with different metastatic potential. | metastatic clones growing in 0.6% 'hard' agar were selected from the non-metastatic rous sarcoma virus (rsv)-transformed tumorigenic b77-3t3 mouse fibroblast line. the incidence of spontaneous lung metastases varied among clones around 100%, while it was lower than 5% in the parental tumor line. the organization of microfilaments, microtubules and intermediate filaments as well as the pattern of extracellular fibronectin matrix were analyzed by immunofluorescence in two representative clones (b7 ... | 1985 | 2982623 |
| rsv provirus with same flanking sequences is found on different size classes of chinese hamster chromosomes. | rous sarcoma virus(rsv)-transformed chinese hamster fibroblasts, containing approximately ten copies of the dna domain comprising a single provirus and its flanking cellular sequences, were arrested in metaphase, and the chromosomes were fractionated by size in a sucrose gradient. the resolution of polymorphic ribosomal genes, the dihydrofolate reductase gene, and the c-src gene demonstrated that the gradient can distinguish between small, medium, and large chromosomes. the same dna domain carry ... | 1985 | 2982758 |
| rous sarcoma virus src gene expression on the growth of quail embryo skin fibroblasts and the establishment of permanent cell lines. | permanent cell lines of quail embryo fibroblasts appear in cultures of cells infected with a wild type strain of rous sarcoma virus (sr-rsv) or with its temperature sensitive transformation mutants (ts-t) (nyts68 and pa101) following a three step process. in step one, infected cells grow twice as fast as the control. the second step consists of a crisis during which the cell population is stationary for four to five weeks. towards the fourth week several foci of cell growth are observed in the f ... | 1985 | 2982767 |
| identification of respiratory virus antigens in middle ear fluids of children with acute otitis media. | antigens of respiratory viruses were tested by immunoassay of the middle ear fluids and nasopharyngeal secretions of 137 children with acute otitis media. the following were found: (1) an epidemic of infection with respiratory syncytial virus (rsv) caused a significant increase in the occurrence of acute otitis media. (2) fifteen percent of the children had rsv antigens in middle ear fluid, and in 7% rsv was the sole pathogen found. adenovirus antigens were found in the middle ear fluid of 3% of ... | 1985 | 2982961 |
| activation of c-myc gene transcription by rous sarcoma virus infection. | transcription of the c-myc gene in chick embryo fibroblast cells was activated 50- to 100-fold by rous sarcoma virus (rsv) infection. more than 30-fold activation of c-myc gene transcription was also observed in rsv-transformed rat cells as compared with the control cells. the increased expression of c-myc gene in these cells was not due to gene amplification or gene rearrangement. this striking increase in expression of c-myc gene may be relevant to neoplastic transformation of rsv-infected cel ... | 1985 | 2984071 |
| deletion in the 3' pol sequence correlates with aberration of rna expression in certain replication-defective avian sarcoma viruses. | the rna expression of a series of replication-defective recovered avian sarcoma viruses (rasvs) were studied. abnormal-sized viral rnas, both larger and smaller than the genome, were observed in the nonproducer cells infected with rasvs containing env and pol deletions. each nonproducer clone contained a single provirus integrated at a unique site and expressed a unique rna pattern. upon rescuing of the sarcoma virus with a helper virus and subsequent cloning, the rna pattern of individual nonpr ... | 1985 | 2985807 |
| no expression of a rous sarcoma virus-induced tumor antigen in mammalian cells infected with retroviruses transducing other oncogenes of the src gene family. | immunization with mouse and rat cells transformed by rous sarcoma virus (rsv) or by b77 avian sarcoma virus (asv) induced complete transplantation resistance against an rsv-induced mouse tumor (csa1m) in syngeneic hosts. in contrast, most of the mice immunized with a fujinami sarcoma virus-transformed rat fibroblast line (fsv-3y1), a feline sarcoma virus-transformed cat fibroblast line (fesv-fef), an abelson leukemia virus-infected balb/3t3 cell line (ablv-3t3), or an uninfected 3y1 cell line co ... | 1985 | 2985859 |
| parabiosis between avian embryos resistant and susceptible to rous sarcoma virus. | parabiosis of chicken embryos was used to determine if resistance or susceptibility to rous sarcoma virus (rsv) tumors could be transferred between rsv-resistant (r) and rsv-susceptible (s) embryos. eggs from rsv-r and rsv-s lines were parabiosed at 12 days of incubation. one week after hatching the chicks were inoculated in the wing web with rsv. birds were examined for tumor lesions through 9 weeks of age. lesion scores of the nonparabiosed rsv-s line were significantly higher than nonparabios ... | 1985 | 2986089 |
| rearrangements of viral and cellular dna are often associated with expression of rous sarcoma virus in rat cells. | rous sarcoma virus (rsv) proviruses integrated within the dna of transformed rat cells frequently display duplications of variable segments of proviral dna upstream of an intact provirus. the rearrangement in the a11 clone of transformed rat cells consists of a partial duplication of both viral and cellular dna segments whose origin is a region of approximately 4 kb encompassing the 3' virus-cell junction. transposition of this dna appears to have occurred at or after virus integration by a mech ... | 1985 | 2986846 |
| virus - tumor cell relationships. in vivo cocultivation of para-influenza type 1 (sendai) virus and of rous sarcoma virus (schmidt-ruppin strain) in mouse ehrlich ascites carcinoma. | co-infection of ehrlich ascites carcinoma (eac)-bearing mice with sendai virus and rous sarcoma virus (rsv) did not result in the formation of complete rsv. sendai virus could be, however, propagated in this system over 8 serial passages. as demonstrated by immunofluorescence and complement fixation reactions, antigens specific to each virus were synthesized in eac cells following either single or mixed virus infection. the virus progens also contained antigenic fractions incorporated from the h ... | 1985 | 2988191 |
| the location of cis-acting regulatory sequences in the human t cell lymphotropic virus type iii (htlv-iii/lav) long terminal repeat. | the location of cis-acting regulatory sequences within the long terminal repeat (ltr) of the human t cell lymphotropic virus type iii (htlv-iii/lav) was determined. an enhancer element capable of increasing the rate of transcription from a heterologous promoter, irrespective of distance and orientation, is located between nucleotides -137 and -17 (cap site +1). the promoter sequences present near the tata box respond to heterologous enhancers. the sequences present between nucleotides -17 and +8 ... | 1985 | 2988790 |
| change of hyaluronic acid synthesis during differentiation of myogenic cells and its relation to transformation of myoblasts by rous sarcoma virus. | hyaluronic acid synthesis was examined in cultures of differentiating chick embryo muscle cells before, during and after fusion. prior to fusion, hyaluronic acid was synthesized and secreted into the medium, but once fusion began this synthesis was reduced significantly. synthesis then increased again after completion of fusion. thus, production of hyaluronic acid was lowest at the time of or right before cell fusion. when myoblasts were transformed by rous sarcoma virus (rsv), a higher amount o ... | 1985 | 2988797 |
| strain differences in the antitumor activity of an immunopotentiator, nocardia rubra cell-wall skeleton, in b10 congenic and recombinant mice. | an immunogenetic evaluation of the antitumor activity of the immunopotentiator nocardia rubra cell-wall skeleton (n. rubra-cws) has been performed using non-virus-producing tumors induced by the schmidt-ruppin strain of rous sarcoma virus (rsv) in b10 congenic and recombinant mice. live tumor cells mixed with either n. rubra-cws or a placebo control were inoculated intradermally into the right flank of syngeneic mice. with n. rubra-cws, the development and growth of b10 mouse tumors, s1018(b10) ... | 1985 | 2989065 |
| surveillance of respiratory viral infections by rapid immunofluorescence diagnosis, with emphasis on the epidemiological development of respiratory syncytial virus infections. | surveillance of certain respiratory viral infections by applying immunofluorescence (if) examinations to samples of nasopharyngeal secretions has been evaluated using a simplified procedure for the preparation of cell smears. samples from 711 children living in different parts of norway were examined during the winter 1982/83 and a positive diagnosis was made for 290 children (41%). temporal epidemic peaks were observed for respiratory syncytial virus (rsv), parainfluenza virus type 3 and influe ... | 1985 | 2989359 |
| local degradation of fibronectin at sites of expression of the transforming gene product pp60src. | local degradation of extracellular fibronectin, a major extracellular adhesive protein, is believed to play an important part in the migration of cells through the extracellular matrix during tumour invasion, morphogenetic movement and trophoblast implantation. fibronectin is lost from the cell surface after transformation with rous sarcoma virus (rsv). by using fluorescent and radiolabelled probes covalently coupled to the surface of substrata, we have recently identified a proteolytic activity ... | 1985 | 2989711 |
| the chromatin structure of rous sarcoma proviruses is changed by factors that act in trans in cell hybrids. | in several lines of rous sarcoma virus (rsv)-transformed rat cells the proviruses are in a configuration typical of active eukaryotic genes. they are sensitive to pancreatic dnase i, with sites hypersensitive to nuclease near the 5' end of the genome, they are close to the nuclear 'cage' and they show a low level of cytosine methylation in cpg doublets. in contrast, in phenotypically untransformed hybrids between these cells and uninfected rat or mouse cells, rsv inactivity is associated with hy ... | 1985 | 2990899 |
| enhancer activity correlates with the oncogenic potential of avian retroviruses. | avian retroviruses lacking an oncogene, such as rous-associated virus 1 (rav-1), rav-2, and td mutants of rous sarcoma virus (rsv), can nevertheless cause leukemias and other neoplastic diseases. during this process, viral dna integrates near a cellular proto-oncogene, such as c-myc, and thus de-regulates its expression. the virus rav-0, on the other hand, is known to be non-oncogenic even in long-term in vivo infections of domestic chickens. the major difference between oncogenic and non-oncoge ... | 1985 | 2990916 |
| partial nucleotide sequence of rous sarcoma virus-29 provides evidence that the original rous sarcoma virus was replication defective. | rous sarcoma virus-29 (rsv-29) is the strain of rsv that has the least number of passages beyond its isolation from chicken tumor no. 1 among all current strains of rsv. biological characterization indicated that it was replication defective. rna analysis of nonproducer clones of rsv-29-infected chicken embryonic fibroblasts showed the presence of a subgenomic message of 2.6 kilobases containing src and a genomic rna of 7.7 kilobases that contains gag, pol, and src, but not env. the src-containi ... | 1985 | 2991593 |
| neoplastic transformation of normal and carcinogen-induced preneoplastic syrian hamster embryo cells by the v-src oncogene. | the ability of cloned rous sarcoma virus (rsv) dna encoding the v-src oncogene to neoplastically transform normal, diploid syrian hamster embryo (she) cells was examined. transfection of rsv dna into early passage she cells resulted in a low but significant number of tumors when treated cells were injected into nude mice. tumors formed with a low frequency (two tumors out of ten sites injected) and only after a long latency period (14 weeks). in contrast to the normal she cells, several differen ... | 1985 | 2991747 |
| [brain tumor induced in dogs by intracerebral inoculation of sr-rsv induced cultured tumor cells--electron microscopic study]. | an experimental transplantable canine brain tumor model with the advantages of rapid tumor growth within 10 days and relative safety for the investigator is presently available. the tumor is produced by intracerebral inoculation of cultured cells derived from a canine brain tumor induced by the schmidt-ruppin strain of the rous-sarcoma virus (sr-rsv). it has potential use as a model in experiments designed to evaluate the effectiveness of chemotherapy and radiotherapy with serial computerized to ... | 1985 | 2991791 |
| quail neural crest cells transformed by rous sarcoma virus can be established into differentiating permanent cell cultures. | quail neural crest cells derived from the truncal neural primordium, infected in vitro by rous sarcoma virus (rsv) in january 1978, were induced to multiply and have been established into permanent cultures. these cultures contain cells that differentiate into melanocytes, neuron-like cells and flat cells. about 50% of these different cell types are tetanus-toxin positive. electrophysiological studies have shown that some cells can generate action potentials similar to those reported in quail ne ... | 1985 | 2992711 |
| glutamic acid decarboxylase activity is stimulated in quail retina neuronal cells transformed by rous sarcoma virus and is regulated by pp60v-src. | rous sarcoma virus (rsv) stimulates in quail embryo neuro-retina (nr) cultures the specific activity of glutamic acid decarboxylase (gad), the enzyme responsible for the synthesis of gamma-aminobutyric acid, a major inhibitory neurotransmitter in nr and in central nervous system. in quail embryo nr cultures transformed by ts ny-68, a thermodependent transformation-defective mutant of rsv, stimulation of gad activity is regulated by pp60v-src, the product of the src gene of rsv. fibroblasts and m ... | 1985 | 2992933 |
| site-specific increased phosphorylation of pp60v-src after treatment of rsv-transformed cells with a tumor promoter. | when vole cells that had been transformed by rous sarcoma virus were treated with the tumor-promoting phorbol ester 12-o-tetradecanoyl-13-acetate (tpa), specific phosphorylation of pp60v-src was increased. partial v8 protease mapping indicated that the increased phosphorylation occurred exclusively on serine residues located in the amino terminus of the molecule. treatment of cells with dimethyl sulfoxide or 4 alpha-phorbol-12,13-didecanoate did not elicit this response. two-dimensional tryptic ... | 1985 | 2994221 |
| estimates of heritability of response to rous sarcomas of chickens. | the stocks used for this investigation consisted of 1039 f3 generation progeny from the cross of two highly inbred lines and 355 and 462 offspring from subpopulations unh 105a and unh 105b, respectively, of a noninbred line of new hampshires. matings were such that b complex alleles were segregated in the three experimental populations with minor exceptions. each chicken was inoculated at 6 weeks of age with a subgroup of rous sarcoma virus (rsv). resulting tumors were subjectively scored on a s ... | 1985 | 2995957 |
| wounding and its role in rsv-mediated tumor formation. | tumors induced in chickens by rous sarcoma virus remain localized at the site of injection even though the animals become viremic. tumors have now been shown to be inducible at other sites if a wound is inflicted or if the tissue is injured by administration of tumor promoters. these findings indicate that local wounding plays a role in the spread of tumorigenicity of rous sarcoma virus. | 1985 | 2996144 |
| establishment of a brain-tumor model in adult monkeys. | a brain-tumor model in adult monkeys may be significant because of the biological similarity to humans as well as the feasibility for surgical manipulation and for sequential computerized tomography (ct) scanning. in the present study, brain tumors were successfully produced in japanese monkeys (macaca fuscata), each weighing 2 to 10.8 kg, with an average age of 5.1 years old. tumor cells were implanted by intracerebral inoculation of 4 x 10(7) chick embryo fibroblasts infected with the schmidt- ... | 1985 | 2997416 |
| the gag and pol genes of bovine leukemia virus: nucleotide sequence and analysis. | the dna sequence of the gag and pol regions of a provirus cloned from a bovine tumor is presented. in order to confirm these results the sequence of portions of a second clone, derived from a virus-producing cell line, was also determined. the gag gene was found to consist of 1179 nucleotides, which probably encode only three proteins: an n-terminal protein of 109 amino acids, a major core protein (p24) of 215 amino acids, and a nucleic acid binding protein (p12) of 69 residues. an open reading ... | 1985 | 2997990 |
| the mannosidase inhibitors 1-deoxymannojirimycin and swainsonine have no effect on the biosynthesis and infectivity of rous sarcoma virus. | the effects of inhibitors, which interfere with oligosaccharide trimming by blocking mannosidases, on the processing and export of the viral glycoproteins of rous sarcoma virus (rsv), have been studied. 1-deoxymannojirimycin (dim) prevents removal of mannose residues from the man9 (glcnac)2 oligosaccharide whereas swainsonine (sw) blocks at a later stage resulting in the formation of so-called hybrid oligosaccharides. under a regime of these inhibitors, proteolytic cleavage of the viral glycopro ... | 1985 | 2998010 |
| pp60src-dependent protein phosphorylation in membranes from rous sarcoma virus-transformed chicken embryo fibroblasts. | the rous sarcoma virus (rsv)-transforming protein, pp60src, is a plasma membrane-associated tyrosine-specific protein kinase. a 36,000-da cellular polypeptide (p36) which is phosphorylated at tyrosine in rsv-transformed chicken embryo fibroblasts (rsv-cef) is also plasma membrane associated. to determine if p36 is directly phosphorylation and kinase activity in situ in the plasma membrane, src-dependent protein phosphorylation in membranes isolated from rsv-cef has been characterized. these memb ... | 1985 | 2998019 |
| influence of base-pairing in the leader region on in vitro translation of rous sarcoma virus rna. | the capacity of the leader region of rous sarcoma virus (rsv) rna to act as a regulator of viral protein synthesis was tested in vitro. when dna/rna hybrids of sufficient length (greater than 90-100 nucleotides) are created within the leader, synthesis of pr76gag is inhibited. the inhibition is dependent upon the length of the hybrid rather than its position with the exception that encumberance of the 5'-terminal 33 nucleotides does block translation. these findings demonstrate that physical alt ... | 1985 | 2998116 |
| modulation of fibronectin gene activity in chick embryo fibroblasts transformed by a temperature-sensitive strain (ts68) of rous sarcoma virus. | transcriptional regulation of the fibronectin gene is a major mechanism for lowering steady-state levels of fibronectin mrna in chick embryo fibroblasts (cef) transformed by rous sarcoma virus (rsv) (1). in the present study, we have measured the change of transcriptional activity of the fibronectin gene in cef transformed by a temperature-sensitive strain of rsv (ts68). ts68-cef maintained at either 35 degrees c or 41 degrees c were shifted to 41 degrees c or 35 degrees c, respectively, at 5-ho ... | 1985 | 2999717 |
| response of b complex haplotypes b22, b24, and b26 to rous sarcomas. | five individual male matings of line unh 105 new hampshires, in which all males and most females were either b22/b24 or b22/b26, produced 462 progeny that fell into six b complex genotypes: b22/b22, b24/b24, b26/b26, b22/b24, b22/b26, and b24/b26. the genotypes of parents and offspring were determined by blood typing for b alloantigens using a panel of antisera. six-week-old chickens were inoculated with rous sarcoma virus (rsv). resulting tumors were scored for size six times over a 10-week per ... | 1985 | 2999742 |