| cellular immunity to mammary tumor virus in normal and tumor-bearing c3h/hen mice. | | 1978 | 208765 |
| mammary tumor virus oncogenesis and tumor immunogenicity in three sublines of the c3h mouse. | mammary tumorigenesis and mammary tumor transplantation immunogenicity have been studied and compared in three sublines of the c3h strain: in standard mammary tumor virus (mtv-s)-infected c3h/he mice; in mtv-s-infected c3h/ki mice; and in mtv-s-free c3hf/he mice. the age at the appearance of the first tumor, the growth rate of the tumors in their first transplant generation, and the immunogenicity of each tumor in syngeneic female recipients have been determined for the first tumor to appear in ... | 1978 | 208767 |
| observations on the question of horizontal transmission of mouse mammary tumor virus. | antigen and tumor incidences in balb/c and c57bl mice after living as weanlings for 5 weeks in cages with mouse mammary tumor virus-infected females were compared with control balb/c and c57bl mice living in the same laboratory. all mice were bred continuously, and third-lactation milks were tested for mouse mammary tumor virus antigen by ouchterlony microimmunodiffusion test. mammary tumor incidences in the cagemates were not significantly different from those in the controls, although the anti ... | 1978 | 208768 |
| genetic transmission of mammary tumour virus in the dbaf mouse strain. | mtv antigens were demonstrable by radioimmunoassay in milk samples from individual dbaf mice, and in samples from (male balb/c x female dbaf) f1 mice. although some samples collected during the first lactation periods of these mice were virus-negative, all samples of later lactation periods were virus-positive. from 75 mice of the [ male balb/c x female (male balb/c x female dbaf)]bc i population, milk samples were collected during one or more lactation periods and tested for the presence of vir ... | 1978 | 208984 |
| type b and type c rna tumor virus replication in single cells. electron microscopy with tannic acid. | simultaneous replication of murine mammary tumor virus (type b) and murine leukemia virus (type c) was demonstrated electron microscopically along continuous stretches of the plasma membrane of single cells in cultures ofthe mm5mt/c1 cell line. types b and c virus buds were discriminated in thin sections with the aid of a tannic acid fixative that revealed the type b surface spikes as a homogeneous band of intermediate density and constant width on the surfaces of some buds (type b), whereas oth ... | 1978 | 209205 |
| estrogen binding in mammary tissue of c3h mice with or without the mouse mammary tumor virus. | substrains of c3h mice, with and without the milk-transmitted form of the mouse mammary tumor virus (mmtv)1, were compared to determine if the presence of mmtv altered estrogen action. uterine weight response to oral diethylstilbestrol was the same for both substrains, (mmtv+ and mmtv-). the concentration of high-affinity estrogen binding sites ("receptors") in lactating mammary tissue did not differ significantly for mmtv+ versus mmtv- mice; the affinity of the estradiol-receptor interaction ap ... | 1978 | 209378 |
| mapping of linear and circular forms of mouse mammary tumor virus dna with restriction endonucleases: evidence for a large specific deletion occurring at high frequency during circularization. | rat hepatoma cells infected with mouse mammary tumor virus contain multiple forms of unintegrated viral dna when grown in the presence of glucocorticoids. using the dna transfer procedure of southern, we have prepared restriction endonuclease fragment maps of these forms of viral dna. the maps indicate that: (i) the major species of viral dna is a linear molecule of 5.9 x 10(6) mr located in the cytoplasm; (ii) the nuclei contain covalently closed circular viral dna of two distinct sizes (5.1 x ... | 1978 | 209450 |
| identification of the mtv-2 gene responsible for the early appearance of mammary tumors in the gr mouse by nucleic acid hybridization. | in the mouse strain gr, the mtv-2 gene controls the expression of large amounts of mammary tumor virus (mtv) antigens in the milk at first lactation. it also controls the early appearance of mammary tumors. we have investigated the number of mtv proviral sequences associated with this mtv-2 gene by nucleic acid hybridization between mtv [(3)h]cdna and dna from gr, b10, and gr-mtv-2(-) mice. b10 and gr-mtv-2(-) mice lack mtv-2 gene expression. the molecular hybridizations revealed that the dna of ... | 1978 | 209461 |
| suppressed development of mammary tumorigenesis in r iii mice treated neonatally with bcg. | | 1978 | 209474 |
| bioactivity of male (sperm transmitted) mouse mammary tumor virus as influenced by donor, recipient and age at treatment. | the sperm collected from mammary tumor virus (mtv)-carrying mice (c3h, balb/cfc3h, balb/cfriii and riii) was separately tested for mammary tumor-inducing activity in (balb/c x c3hf)f1, (balb/c x riiif) f1, and balb/c female recipients by i.p., injection of 0.1 ml of the sperm at 1-2 weeks or at 3 months of age. a total of 551 recipents was observed, including control mice. the results may be summarized as follow: 1) mammary tumor incidence in experiments with or without histocompatibility betwee ... | 1978 | 209593 |
| suppressed murine mammary tumor virus (mumtv) expression in riii female mice treated neonatally with goat antiserum to mumtv. | passive immunization of newborn inbred riii (r3) mice with the globulin fraction of goat antiserum to murine mammary tumor virus (mumtv) successfully suppressed mumtv expression in the milk of some of the treated mice throughout nine successive lactations. no mammary tumors developed in the mumtv-suppressed mice during the first 9 months, whereas all untreated r3 female breeders expressed mumtv in the milk of the third lactation, and all developed tumors before 9 months of age (mode and median: ... | 1978 | 210290 |
| prevalence of murine mammary tumor virus antibody and antigens in normal and tumor-bearing feral mice. | approximately 20% of normal male and female feral mice (mus musculus) from areas with populations having either high [lake casitas (lc) and la puente] or low (bouquet canyon) spontaneous lymphoma incidence expressed murine mammary tumor virus (mumtv) gp52 in specific tissues. sera from a low percentage (6%) of mice from the same trapping areas contained precipitating antibody specific for mumtv. although moderate to high levels of mumtv gp52 were expressed in mammary tumor tissues of 3 of 7 lc m ... | 1978 | 210292 |
| heterogeneity of tumor cells from a single mouse mammary tumor. | by the use of a variety of cell culture and separation methods, four cell lines were isolated from a single autochthonous balb/cfc3h mammary tumor. these lines differ markedly from each other in culture morphology, various in vitro growth properties, expression of murine mammary tumor virus antigen, and karyotype, yet all four lines are tumorigenic in normal, syngeneic hosts, yielding tumors of generally similar histology, although distinct from the original neoplasm. three of the four lines hav ... | 1978 | 210930 |
| mammary tumour virus and casein gene transcription during mouse mammary development. | | 1978 | 211437 |
| mouse mammary tumor virus and murine leukemia virus cell surface antigens on virus producer and nonproducer mammary epithelial tumor cells. | | 1978 | 211719 |
| comparative susceptibilities of hybrid mice to four mammary tumor viruses from two mouse strains. | | 1978 | 212182 |
| hormonal induction of mammary tumor viruses and its implications for carcinogenesis. | the purpose of this study was to evaluate the possibility that hormones and mouse mammary tumor virus (mumtv) are cocarcinogenic for mammary epithelium. results of our investigations in vivo and in vitro suggest: (a) hormones promote mammary carcinogenesis in balb/c females whether mumtv is germinally (balb/c) or horizontally (balb/cfc3h) transmitted; the rate of carcinogenesis in balb/cfc3h females is substantially faster than it is in balb/c, but the final mammary carcinoma incidence is approx ... | 1978 | 212187 |
| dexamethasone-mediated induction of mouse mammary tumor virus rna: a system for studying glucocorticoid action. | we have investigated the mechanisms by which dexamethasone (a synthetic glucocorticoid) stimulates the production of mouse mammary tumor virus (mmtv) by cell cultures derived from mammary carcinomas of gr mice. treatment of these cells with dexamethasone stimulates a rapid accumulation of intracellular virus-specific rna which is dependent upon rna synthesis but not upon dna or protein synthesis. the effect of dexamethasone is probably mediated by a specific and saturable glucocorticoid receptor ... | 1975 | 212202 |
| genetic analyses of differences in incidence of mammary tumors and reticulum cell neoplasms with the use of recombinant inbred lines of mice. | the influence of genes, in addition to genes in the h-2 complex, that effect the genesis of mammary tumors was studied. the recombinant inbred (ri) cxb lines were chosen for this investigation, because they are well suited for the study of the genetics of a trait for which the genotype affects probability of phenotype expression and which therefore is measured as incidence. females of seven ri lines (cxbd, cxbe, cxbg, cxbh, cxbi, cxbj, and cxbk) and their progenitor strains c57bl/6by (b6) and ba ... | 1978 | 212568 |
| involvement of mouse mammary tumor virus in spontaneous and hormone-induced mammary tumors in low-mammary-tumor mouse strains. | the involvement of the mouse mammary tumor virus (mtv) in spontaneous and hormone-induced mammary tumors in low-mammary-tumor mouse strains was studied by comparing the amounts of mtv rna and mtv dna sequences in mammary tumors and other tissues of mice with an without hormonal treatments. the following results were obtained. (i) mammary tumors which appeared in c3h mice as a result of an infection with mtv contained more mtv dna compared with noninfected organs; these mammary tumors also contai ... | 1978 | 212580 |
| strain-specific markers for the major structural proteins of highly oncogenic murine mammary tumor viruses by tryptic peptide analyses. | tryptic peptide analyses were performed on the major structural 52,000- and 36,000-dalton glycoproteins (gp52 and gp36-38) and the nonglycosylated 28,000-, 14,000-, and 10,000-dalton proteins (p28, p14, and p10) of the highly oncogenic murine mammary tumor viruses (mmtvs) of c3h, riii, and gr mice, i.e., mmtv(c3h), mmtv(riii), and mmtv(gr), respectively. each virus was grown in both murine and feline cells to ensure the virus-coded nature of each peptide analyzed. the gp36-38 peptide maps of all ... | 1978 | 212589 |
| prospects of vaccines against cancer in man. | preventive immunization is the cheapest and most effective approach to the management of epidemic disease. certain forms of cancer, including burkitt's lymphoma, carcinoma of the cervix, primary liver cancer, acute leukaemia and breast cancer show many characteristics of epidemic disease, and the possibility of producing preventive vaccine against these conditions merits serious consideration. | 1978 | 212839 |
| genetic control of endogenous murine mammary tumour viruses reinvestigated. | | 1978 | 213287 |
| occurrence of antibody against intracytoplasmic a-particles of mouse mammary tumor virus in sera from breast cancer patients. | acetone-fixed smears of dba/2 mouse leukemia cells that produce clusters of intracytoplasmic a-particles (pronucleocapsids of mouse mammary tumor virus) were employed as an indirect immunofluorescence system to detect the antibody to a-particles in human sera. with positive test sera, specific fluorescence was easily detectable as discrete cytoplasmic granules at the site of a-particle clusters. the antibody was found in 26 (60%) out of 43 breast cancer patient sera and 4 (25%) of 16 mammary fib ... | 1978 | 213337 |
| murine mammary tumor virus (mumtv) infection of an epithelial cell line established from c57bl/6 mouse mammary glands. | | 1978 | 213889 |
| [virus and human cancers]. | | 1978 | 214215 |
| chemical carcinogenesis in c3h/stwi mice, a worthwhile experimental model for breast cancer. | | 1978 | 214224 |
| demonstration of mouse mammary tumour virus (mumtv) antigenicity in human milk by means of immunodiffusion technique. | using the micro-ouchterlony immunodiffusion technique, we were able to demonstrate mouse mammary tumour virus (mumtv) antigenicity in the 1.26-1.28 g/ml density fraction prepared from pooled human milk samples after treatment with detergents and ether. the cross-reacting antigen(s) was precipitated by rabbit antisera to mumtv-b particles prepared from murine milk and intracytoplasmic a particles (iap) isolated from mouse mammary tumour tissue. by confluence of precipitin lines, the human milk "c ... | 1978 | 214323 |
| naturally occurring humoral immunity to murine mammary tumor virus (mumtv) and mumtv gp52 in mice with low mammary tumor incidence. | | 1978 | 214408 |
| modulation of mouse mammary tumor virus production in the mjy-alpha cell line. | implantation of the mouse mammary tumor virus (mmtv)-producing mammary tumor cell line mjy-alpha into isogeneic mice elicited both humoral and t-cell responses against mmtv virion antigens. the carcinosarcomas which developed from the implanted cells showed a significant decrease in mmtv synthesis, compared with cells remaining in culture, which was detectable as early as 7 days after implantation and for five transplant generations. electron microscopic examination of thin sections of the tumor ... | 1978 | 214582 |
| isolation of host-range variants of mouse mammary tumor viruses that efficiently infect cells in vitro. | host-range variants of mouse mammary tumor virus (mmtv) have been isolated that have the ability to productively infect cells in vitro with high efficiency (at multiplicities of infection </=1) and with extremely short latent periods to the production of de novo virus (as short as 4 days after infection). these variants of the highly oncogenic mmtv of riii, c3h, and gr mice were obtained by serial virus passage in feline cells. the resultant variant stocks react in group-specific radioimmunoassa ... | 1978 | 214796 |
| translation of mouse mammary tumor virus rna: precursor polypeptides are phosphorylated during processing. | | 1978 | 214954 |
| an improved procedure for purifying rna tumor viruses from malignant tissue. | a convenient method for purifying rna tumor viruses is described. viruses banded in isopycnic gradients are contaminated with membranes that can be removed by velocity sedimentation in glycerol gradients. on sodium dodecyl sulfate (sds) gel electrophoresis, the particles purified by these procedures from mouse mammary tumor tissue show protein profiles typical of those observed with virus purified from milk. | 1977 | 214996 |
| mammary tumor virus expression in the gr mouse strain: efficiency of chromosomal and extrachromosomal transmission. | | 1978 | 215482 |
| detection of mouse mammary tumor virus rna in balb/c tumor cell lines of nonviral etiologies. | a complementary dna (cdna) probe to mouse mammary tumor virus (mmtv) rna was synthesized using calf thymus dna oligonucleotides as a random primer. this probe was then used to study the expression of mmtv rna in cell lines from balb/c tumors induced in vivo either spontaneously or in response to viral, chemical, or hormonal stimuli. the cdna had a length of approximately 400 to 500 nucleotides and specifically hybridized to mmtv rna and balb/c lactating mammary gland rna, but not to moloney leuk ... | 1978 | 215778 |
| strain-related variation in the interaction of ferritin-conjugated plant lectins with mouse mammary tumor viruses. | | 1979 | 216482 |
| [direct electron-microscopy virus demonstration in veterinary medicine]. | | 1979 | 216536 |
| h-2 restriction and non-restriction of t-cell-mediated cytotoxicity against mouse mammary tumour targets. | | 1978 | 216918 |
| structural components of mouse mammary tumor virus. iii. composition and tryptic peptides of virion polypeptides. | | 1978 | 217150 |
| phosphoproteins of the murine mammary tumor virus. | | 1978 | 217155 |
| endogenous mouse mammary tumor virus dna is distributed among multiple mouse chromosomes. | | 1979 | 217167 |
| localization of murine mammary tumor virus polypeptides on the surface of tumor cells. | | 1979 | 217688 |
| specificity of response to viral proteins in horses infected with equine infectious anemia virus. | three structural proteins of equine infectious anemia virus were purified, labeled with 125i, and utilized in radioimmunoassays with horse sera and antisera to heterologous retroviruses. whereas radioimmunoassay titers for the major protein, p25, were 500- to 1,000-fold higher than titers in immunodiffusion, for clinical purposes these two procedures were equivalent. antibodies to two low-molecular-weight proteins, p12 and p10, were also found in infected horses, but with a lower frequency and l ... | 1979 | 217831 |
| integration and transcription of mouse mammary tumor virus dna in rat hepatoma cells. | rat hepatoma cells infected with mouse mammary tumor virus (mmtv) acquire viral dna that becomes covalently linked to the cell dna. using restriction endonucleases and the dna transfer procedure of southern [southern , e.m. (1975) j. mol. biol. 98, 503--517], we have studied the sites in cellular dna into which mmtv dna inserts. these experiments indicate that: (i) there are many sites in cell dna into which mmtv dna integrates; (ii) the junctions between viral and cellular dna occur within a li ... | 1979 | 218215 |
| high incidence of mammary tumors in mice with inherited asplenia carriers for the nude gene. | a colony of mice suffering from dominant hemimelia associated with agenesis of the spleen has been developed and characterized during the past 7 years. the hereditarily asplenic (dh/+) mice have a very low incidence (9%) of spontaneous mammary tumors (smt). asplenic (dh/+) females were mated with mice homozygous (nu/nu) for hereditary athymia (nude) having a balb/c background. balb/c females heterozygous for the nu gene and with spleen (nu/+,+/+) have a moderate incidence (12%) of smt, whereas n ... | 1979 | 218729 |
| murine mammary tumor virus expression during mammary tumorigenesis in balb/c mice. | steady-state levels of murine mammary tumor virus (mumtv) rna were quantitated during mammary tumorigenesis in balb/c mice by molecular hybridization with a representative mumtv complementary dna (cdna) probe. hyperplastic alveolar nodule (han) lines are preneoplastic mammary lesions that were induced in balb/c mice by hormones alone or in combination with 7,12-dimethylbenz(a)anthracene and give rise to mammary tumors. the hormone-induced han lines d1 and d2 contained detectable amounts of hybri ... | 1979 | 219243 |
| autogenous antibodies against the murine mammary tumor virus in strains of mice with low incidences of mammary tumors. | the radioimmunoprecipitation assay for the murine mammary tumor virus (mumtv) was used to detect naturally occurring antibodies against mumtv in 3 groups of highly inbred mouse strains. 1) some strains had high incidences of mammary tumors, such as strains gr and c3h. antibodies against mumtv were detected in the sera of females of these strains at early ages. 2) some mouse strains had low incidences of mammary tumors with an intermediate mumtv expression, such as strains c3hf, riiif, and balb/c ... | 1979 | 219283 |
| [morphogenesis of intracytoplasmic oncornaviruses]. | intracytoplasmic oncorna viruses type-a are de novo formed in the cytoplasma, independently of the organella. in the early phase of the morphologenesis an electrondense patch-like area and the disappearence of the ribosomes can be observed. double-membrane structures consisting of gylcoprotein can be seen in form of segments, horseshoes or rings. in the centre of the viruses ribosoma-like inclusions may be observed. viruses of tubular structure appear to be of peculiar forms of the formation of ... | 1979 | 219328 |
| eukaryotic gene regulation studies with mouse mammary tumor virus in tissue culture cells. | the transcriptional regulation of mouse mammary tumor virus has been investigated in cell culture systems. these systems offer several insights into mechanisms of gene control including tenfold stimulation by glucocorticoids and spontaneous alterations in levels of constitutive transcription. | 1978 | 219353 |
| genetics of resistance of animals to viruses: i. introduction and studies in mice. | | 1978 | 219668 |
| studies on cell surface antigens of mouse leukemic and normal lymphocytes. ii. relationships between mammary leukemia, gross virus related and major histocompatibility antigens on l1210 leukemic lymphocytes. | the presence of ml antigen on leukemia l1210 cells was confirmed by different procedures. in addition, by applying appropriate absorptions and blocking techniques combined with ferritin labelled antibodies in electron microscopy (em), the independent localization of ml antigen and murine leukemia virus gross (mulv-gross) cellular antigen on l1210 cells was demonstrated. the ferritin labeled antigenic sites appeared to be free from budding viral particles. in further studies the 3m kci extracts o ... | 1978 | 219815 |
| simultaneous production of casein and mammary tumor virus in mouse mammary epithelial cells grown on floating collagen gels. | simultaneous production of casein and mammary tumor virus (mtv) was analyzed in monolayer cultures of mammary epithelial cells from pregnant balb/cfc3h mice. a comparison of the 2 cell culture substrata, plastic culture dish and floating collagen gel, showed that the latter supported a much higher degree of simultaneous casein and mtv production in the presence of insulin, cortisol and prolactin in serum-free culture medium. importance of floating collagen gel was further shown by delaying the f ... | 1979 | 219954 |
| humoral antibodies to mouse mammary tumor virus in sera from breast cancer patients. | | 1978 | 220186 |
| purification of murine oncornaviral phosphoproteins using alkyl agarose derivatives.. | methods for the purification of both murine mammary tumor (type b) and murine leukemia (type c) oncornaviral phosphoproteins are described, in which chromatography on alkyl-agarose derivatives is used as the primary fractionation step. gel filtration or ion exchange chromatography on phosphocellulose was the only subsequent step required for the purification of the type b and type c viral proteins, respectively. the two-step protocols also resulted in the co-purification of a low molecular weigh ... | 1979 | 220261 |
| differential distribution of mouse mammary tumor virus-related sequences in the dna's of rats. | | 1979 | 220450 |
| longterm effects of neonatal anterior hypophysial isografts on the mammary gland of mammary tumor virus-expressed mice. | | 1979 | 220619 |
| serological identification of viral and virus-related antigens on dba/2 mouse leukemia lymphocytes. | allogenic, semisyngeneic and syngeneic sera of animals immunized with ml-positive leukemia l1210 cells, besides anti-ml antibodies, contain antibodies which react with gross cellular surface antigen. ml antigen and gross cellular surface antigen were shown by the immunoferritin test in electron microscopy, and by the blocking test, to be situated on different parts of the cell surface. no budding viral particles were found on the areas occupied by these antigens. by distinguishing the ml antigen ... | 1979 | 220930 |
| immunological cross reaction between sera from patients with breast cancer and mouse mammary tumor virus. | sera of japanese women with breast cancer and without disorders of the mammary gland gave positive immunofluorescence reaction with mouse mammary tumor cells (mmt cells) producing type-a and type-b virus particles. among these, 55.1% (49/89) of the sera from patients with breast cancer reacted with mmt cells, whereas 60% (3/5) of the sera from patients with benign mammary hyperplasia (2 of 3 mastopathies, 1 of 2 cystosarcoma phyllodes), 30% (12/40) of the patients with other than breast cancer ( ... | 1979 | 221302 |
| cell-free synthesis of mouse mammary tumor virus pr77 from virion and intracellular mrna. | mouse mammary tumor virus (mumtv) was purified from two cell lines (gr and mm5mt/c1), and the genomic rna was isolated and translated in vitro in cell-free systems derived from mouse l cells and rabbit reticulocytes. the major translation product in both systems was a protein with the molecular weight 77,000. several other products were also detected, among them a 110,000-dalton and in minor amounts a 160,000-dalton protein. all three polypeptides were specifically immunoprecipitated by antiseru ... | 1979 | 221668 |
| endogenous mammary tumour virus dna varies among wild mice and segregates during inbreeding. | proviruses of the mouse mammary tumour virus (mmtv) endogenous to normal mice can be identified by molecular hybridisation and distinguished using restriction endonucleases. feral mice display marked heterogeneity with respect to the number of copies and the sites of insertion of endogenous mmtv-specific dna, with occasional mice apparently free of mmtv dna. several different mmtv proviruses present in laboratory mice have segregated like stable, independent genetic elements during the inbreedin ... | 1979 | 221817 |
| identification of the messenger rnas coding for the gag and env gene products of the murine mammary tumor virus. | full-length (35s) genomic rna from murine mammary tumor virus (mumtv) was translated in vitro, using a reticulocyte lysate system, into proteins of 105,000, 75,000, 65,000, 35,000, and 27,000 daltons. these proteins were all immunoprecipitable with a monospecific antiserum to the major viral core protein, p27, but not with antiserum to the major viral envelope glycoprotein, gp47. translation in vitro of rna of about 24s size extracted from mumtv yielded proteins similar in size and immunoreactiv ... | 1979 | 221904 |
| regulation of mouse mammary tumor viral rna synthesis in embryonal carcinoma cells and in teratocarcinoma derived myoblasts. | | 1979 | 222273 |
| integration of the dna of mouse mammary tumor virus in virus-infected normal and neoplastic tissue of the mouse. | we have used restriction endonucleases which cleave the dna of mouse mammary tumor virus (mmtv) at one site (eco ri) and several sites (pst i, sac i and bam hi) to study infection and mammary tumorigenesis in mice. proviruses acquired during infection of balb/c mice foster-nursed by virus-producing c3h females can be distinguished from the mmtv proviruses endogenous to uninfected balb/c mice by the nature of the fragments generated with pst i and bam hi. using this assay, we show that lactating ... | 1979 | 222456 |
| idiopathic mammary tumors in balb/c mice. | a colony of balb/c mice consisting of two sublines with a high incidence of mammary tumors was examined for the presence of a mammary tumor virus (mumtv). the mammary tumor incidences in the two sublines were 18% and 35% at average tumor age 19-20 months. over a period of 8 years, their milk at third to tenth lactations were monitored for the presence of mumtv antigen,and the milk and tumors were examined for the presence of b particles. neither antigen nor b particles were found. milk and tumor ... | 1979 | 222695 |
| the cause of species differences in mammary tumourigenesis: significance of mammary gland dna synthesis. | the causes of species differences in mammary tumourigenesis are briefly discussed from the genetical and environmental points of view, although no firm conclusions can be drawn. distinct differences in mammary gland dna synthesis were found between female mice and rats, which behave very differently in mammary tumourigenesis. based on the importance of mammary gland dna synthesis in mammary tumourigenesis, the differences in mammary gland dna synthesis between species is hypothesized to be a maj ... | 1979 | 223022 |
| vicinal relationships between the major structural proteins of murine mammary tumor virus. | | 1979 | 223301 |
| characterization of purified structural proteins of murine mammary tumor virus. | | 1979 | 223309 |
| effect of dexamethasone on expression of endogenous mouse mammary tumor virus sequences in balb/c tumor cell lines. | | 1979 | 223313 |
| immunohistochemical evidence for rna virus related components in human breast cancer. | the localization of antigenic components with cross-reactivity to a 52,000 dalton group specific glycoprotein (gp52) of the mouse mammary tumor virus (mmtv) in paraffin sections of human breast carcinomas is described using an indirect immunoperoxidase method. this method was first optimized on paraffin sections of mouse mammary tumors. the specificity of the reaction observed in the human tissues was established by absorption of the specific igg with: a) purified gp52; b) several relevant and i ... | 1979 | 223491 |
| virus particles in normal prostate tissues of mice from ten strains, with special reference to type-b virus particles. | prostate tissues of a total of 61 normal mice from 10 different strains, including high (c3h/dm, riii/dm, and a/dm) and low (balb/c/dm, c3hf/bi/dm, and c3hf/he/tex) mammary cancer, and high (akr/dm) and low (cba/j/cr, sjl/j/cr, and c57/bl/6/tex) leukemia strains were examined by electron microscopy for the presence of virus particles. these studies demonstrated that type-b virus particles were present in normal prostate tissues of some old mice from all the three high (c3h/dm, riii/dm, and a/dm) ... | 1979 | 223933 |
| structural analysis of the intracellular rnas of murine mammary tumor virus. | we have characterized murine mammary tumor virus (mumtv)-specific rna in several types of cells in which viral dna is transcribed into rna: cultured gr mouse mammary tumor cells, s49 lymphoma cells from balb/c mice, lactating mammary glands from c57bl/6 mice, and mink lung cells infected in vitro with mumtv. in all cell types studied, there are three distinct species of intracellular viral rna, with sedimentation coefficients of 35s, 24s, and 13s (or molecular weights of 3.1 x 10(6), 1.5 x 10(6) ... | 1979 | 224216 |
| immunocytochemical distribution of mouse mammary tumor virus antigens in balb/cfc3h mammary epithelium. | the distribution of mouse mammary tumor virus (mumtv) antigens was studied in normal, preneoplastic, and neoplastic mammary epithelia from female balb/cfc3h mice with the use of a polyvalent anti-mumtv serum and indirect immunoperoxidase techniques. the mumtv antigens were on the apical surface or in focal cytoplasmic aggregates or diffused throughout the infected cells. as much as 70% of all cells in adenocarcinomas and as much as 100% of all cells in preneoplastic hyperplastic alveolar nodules ... | 1979 | 224238 |
| generation of a mouse mammary tumor virus (mmtv) pseudotype of kirsten sarcoma virus and restriction of mmtv gag expression in heterologous infected cells. | | 1979 | 224586 |
| mouse mammary tumor virus infections: viral expression and tumor risk. | concentrations of murine mammary tumor virus (mumtv) antigen in the milk of individual naturally infected balb/cfc3h and balb/c mice given injections of mumtv were related to their risk of developing a mammary tumor. two distinct groups of mumtv-infected mice were identified. one group exhibited high viral antigen levels in their milk (greater than or equal to 100 micrograms/ml), whereas the other group exhibited low viral antigen levels in their milk (less than or equal to 3 micrograms/ml). mic ... | 1979 | 225501 |
| phosphorylation of murine mammary tumor virus precursor polypeptides. | phosphorylation of the murine mammary tumor virus (mumtv) structural proteins was studied in an mumtv-infected epithelial cell line derived from a balb/cf c3h mouse mammary tumor. immunoprecipitation of 32p-labeled cell extracts with monospecific anti-p27 serum revealed that phosphorylation occurred at the stage of the core-protein polyprotein precursor prp75. two forms of phosphorylated prp75 were found: one migrating with an apparent molecular weight of 80,000, and the other with a molecular w ... | 1979 | 225520 |
| identification of mouse mammary tumor virus-specific mrna. | complementary dna corresponding to the rna genome of mouse mammary tumor virus was used to identify viral rna contained in polysomes of a virus-producing mammary tumor cell line. separation of polysomal mrna by agarose gel electrophoresis, transfer of the rna to diazobenzyloxymethyl paper, and hybridization with 32p-labeled mouse mammary tumor virus complementary dna revealed three viral rna size classes of 10, 8.8, and 4.4 kilobases in length, respectively. | 1979 | 225528 |
| composition, arrangement and cleavage of the mouse mammary tumor virus polyprotein precursor pr77gag and p110gag. | | 1979 | 226264 |
| levels of mammary tumor virus proteins (mtvp27 and mtvgp52) in the milk of low and high mammary cancer mouse strains of japanese origin compared with european and american strains. | | 1979 | 226487 |
| antitumor immunity in breast cancer patients. biologic and therapeutic implications. | as judged by in vivo and in vitro indices of cellular immunity, mammary carcinogenesis appears to be associated with immunogenic changes in the transformed cells and prognostically favorable antitumor cell-mediated immunity in the host. the prognostically favorable cell-mediated immunity appears to be directed against a component(s) which is shared by most stage 0 in situ breast cancers and the major envelope glycoprotein (gp55) of riii murine mammary tumor virus. progressive disease is associat ... | 1979 | 226697 |
| regulation of mouse mammary tumor virus gene expression by glucocorticoid hormones. | several laboratories have documented that glucocorticoid hormones markedly stimulate the expression of mouse mammary tumor virus genes in a variety of mouse mammary tumor cells and in infected heterologous cells. the effect of the hormone appears to be a rapid and specific augmentation of the synthesis of viral rna, mediated by interaction with glucocorticoid receptor proteins. the availability of virus-specific reagents and recent developments in the molecular biology of rna tumor viruses now p ... | 1979 | 226870 |
| in vitro infectivity assay for mouse mammary tumor virus. | studies of mouse mammary tumor virus (mmtv) have been impeded by the lack of an in vitro infectivity assay. we have developed a rapid, quantitative in vitro assay for mmtv infectivity based on the detection of positively staining foci by immunoperoxidase. this assay and a 50% end-point titration of mmtv infectivity gave identical virus titers. infection of a rat hepatoma cell line, a feline kidney cell line, and a normal murine mammary gland cell line by virus from the mouse mammary tumor gr3a c ... | 1979 | 226995 |
| intracytoplasmic type a virus-like particles in angioimmunoblastic lymphadenopathy. | virus-like particles which seemed to be oncogenic have not been observed clinically in human neoplasms. however, we found some virus-like particles in the cytoplasm of a few proliferating cells in the lymph nodes of one patient with angioimmunoblastic lymphadenopathy. these were very similar to intracytoplasmic type a particles seen in the mazon-pfizer monkey virus and a mammary tumor virus in a mouse. | 1979 | 227573 |
| sequence homology of nucleic acids from human breast cancer cells and complementary dna's from murine mammary tumor virus and mason-pfizer monkey virus. | simultaneous presence of murine mammary tumor virus- and mason-pfizer monkey virus-specific sequences has been detected in nucleic acids isolated from some human breast tumors and from mcf-7 cells, a well-characterized human breast cancer cell line. carefully characterized long complementary dna transcripts were used in the molecular hybridization experiments. from the data that are presently available, it would appear that when homology is detected with one of the mammary tumor probes the other ... | 1979 | 227595 |
| regulation of transcription by dna-bound non-histone nuclear proteins. | purified non-histone proteins from mouse mammary cells bind specifically to homologous dna or chromatin. complexes of non-histone protein with dna or chromatin, isolated on agarose columns, were transcribed with both escherichia coli rna polymerase and rna polymerase b from calf thymus. the fact that complexing of dna with non-histone proteins increases transcription by e. coli rna polymerase but not by rna polymerase b suggests different mechanisms of transcription by these two enzymes. similar ... | 1979 | 227684 |
| diversity of mammary tumor viral genes within the genus mus, the species mus musculus, and the strain c3h. | proviral sequences complementary to the c3h mouse mammary tumor virus rna genome are present in the dna of early occurring mammary tumors of c3h/hen mice and are absent from apparently normal c3h/hen tissues; these sequences are non-germ line transmitted in c3h/hen mice and have been termed tumor-associated sequences; (w. drohan et al., j. virol. 21:986-995, 1977). we report here that tumor-associated sequences are present in the dna of spontaneous mammary tumors that occur early in the life of ... | 1979 | 228059 |
| induction of mouse mammary tumor virus rna in mammary tumors of balb/c mice treated with urethane, x-irradiation, and hormones. | the involvement of mouse mammary tumor virus (mtv) in the development of mammary tumors of nonviral etiology in balb/c mice was studied by measuring the levels of mtv rna, mtv dna, and mtv proteins in spontaneously arising and hormonally, chemically, and/or physically induced mammary tumors of balb/c females. the following results were obtained. (i) spontaneous mammary tumors contained very low levels of mtv rna; 4 x 10(-6)% of the the cytoplasmic rna was mtv rna. no mtv proteins could be demons ... | 1979 | 228060 |
| organization of mouse mammary tumor virus-specific dna endogenous to balb/c mice. | we used restriction endonucleases to prepare physical maps of the mouse mammary tumor virus (mmtv)-specific dna endogenous to the balb/c mouse strain. the mapping was facilitated by the dna transfer procedure, using complementary dnas specific for the whole and for the 3' terminus of mmtv rna to detect fragments containing viral sequences. the strategies used for the arrangement of fragments into physical maps included sequential digestions with two or three enzymes; preparative isolation of eco ... | 1979 | 228072 |
| polyprotein precursors to mouse mammary tumor virus proteins. | mouse mammary tumor virus (mmtv) derived from the culture medium of gr cells contained seven proteins, identified as gp55, gp33, p25, pp20, p16, p12, and p10. the major viral phosphoprotein was the 20,000-molecular-weight protein, pp20. immunoprecipitation of cytoplasmic extracts from pulse-labeled gr cells identified three mmtv gag-specific proteins, termed pr78(gag), pr110(gag), and pr180(gag+). these intracellular polyproteins were precipitable from cytoplasmic extracts by antisera to virions ... | 1979 | 228073 |
| hormonal regulation of murine mammary tumor virus rna expression during mammary tumorigenesis in balb/c mice. | the effects of glucocorticoids and prolactin on murine mammary tumor virus (mumtv) rna expression in preneoplastic outgrowth lines and mammary tumors in balb/c mice were investigated. hyperplastic alveolar nodules (han) and a ductal hyperplasia (dh) are induced in virgin balb/c mice by prolonged hormonal stimulation or treatment with 7,12-dimethylbenz(a)anthracene or both. mice bearing han or dh outgrowth lines and mammary tumors that arose from the outgrowth lines were treated with glucocortico ... | 1979 | 228079 |
| mouse mammary tumor virus genome expression in chemical carcinogen-induced mammary tumors in low- and high-tumor-incidence mouse strains. | involvement of mouse mammary tumor virus (mmtv) in 7,12-dimethylbenz[a]anthracene (dmba)-induced mammary tumorigenesis was investigated in low- (balb/c) and high- (balb/cfc3h) mammary-tumor-incidence mouse strains. both strains contain endogenous mmtv integrated into the cellular genome. additionally, balb/cfc3h mice are infected with exogenous mmtv-s which is responsible for a higher incidence of mammary tumors in breeding females. administration of dmba to virgin mice of both strains resulted ... | 1979 | 228289 |
| expression of mumtv antigens in rabbits and rats infected with mumtv. | | 1979 | 228486 |
| [development of a cellular immune response in a highly cancer-susceptible c3h/he strain of mice and its nonfactor substrain c3h/f after the transplantation of a syngeneic mammary gland tumor]. | syngeneic mammary gland tumor (mmt-1) grew slower in non-factor c3h/f (mtv-l) mice than in wirus-positive c3h/he (mtv-s) mice. the immunization of mice with tumor (mmt-1), inoculated and later excised, revealed a higher immune reactivity in the mice of the non-factor substrain. in studying the dynamics of the cytotoxic activity of lymphocytes in regional lymph nodes cytotoxically active lymphocytes were found to appear in c3h/f mice on day 6 after the inoculation of tumor (mmt-1), while the area ... | 1979 | 228516 |
| [effect of succinic acid on spontaneous tumor frequency and longevity in c3h/sn mice]. | | 1979 | 228918 |
| failure to induce protection against transplanted mammary tumours by vaccination with the purified murine mammary tumour virus structural proteins gp52 and p28. | | 1979 | 228941 |
| acceleration of mammary cancer development by grafting of fetal mammary mesenchymes in c3h mice. | transplantation of fetal mammary gland mesenchyme into mammary glands of 2-month-old syngeneic virgin mice resulted in focal re-enactment of events that normally occur probably during fetal and early postnatal development of the mammary gland. portions of the recipient's mammary duct system in contact with the fetal mammary mesenchyme underwent branching and proliferation in a pattern resembling that of rudimentary mammary gland development. this process occurred in c3h mice regardless of whethe ... | 1979 | 229052 |
| aetiology of breast cancer: a brief review. | cancer of the human breast is probably a group of diseases which have different causes. changes in hormonal status that increase breast cancer risk probably do so by 'promoting' tumour development rather than by 'initiating' it. exogenous oestrogens seem to act as tumour promoters in this context, but there is to date no evidence that oral contraceptives, some of which contain oestrogens in low dosage, increase breast cancer risk. on the contrary, they appear to reduce the incidence of benign br ... | 1979 | 229089 |
| conserved region of mammalian retrovirus rna. | the viral rnas of various mammalian retroviruses contain highly conserved sequences close to their 3' ends. this was demonstrated by interviral molecular hybridization between fractionated viral complementary dna (cdna) and rna. cdna near the 3' end (cdna(3')) from a rat virus (rpl strain) was fractionated by size and mixed with mouse virus rna (rauscher leukemia virus). no hybridization occurred with total cdna (cdna(total)), in agreement with previous results, but a cross-reacting sequence was ... | 1979 | 229272 |
| immunologic heterogeneity of tumor cell subpopulations from a single mouse mammary tumor. | five subpopulations (66, 67, 68h, 168, and 4.10lm) obtained from a single balb/cfc3h mammary adenocarcinoma were used to assess intratumor immunologic heterogeneity. balb/c and balb/cfc3h mice were immunized with each of the subpopulations, and lymph node cells (lnc) from immunized animals were tested for cell-mediated immunity (cmi) to each subpopulation in vitro by chromium release and microcytotoxicity tests and in vivo by winn assays. the immunogenic character of the subpopulations differed ... | 1979 | 229294 |
| gene order of mouse mammary tumor virus precusor polyproteins and their interaction leading to the formation of a virus. | | 1979 | 229627 |
| assessment of cellular immune response to cancer of the breast. | cellular immune competence and cell-mediated immunity to tumor antigens have been studied in patients with breast cancer. some patients have been shown to have depressed lymphoproliferative responses to phytohemagglutinin and in mixed leukocyte culture. in some cases, this depression appeared attributable to suppressor cells. many patients with breast cancer had a cellular immunity to extracts of autologous or allogenetic tumors, as detected by lymphoproliferation and leukocyte migration inhibit ... | 1979 | 229763 |