Oncorna Viruses Research Articles

T-cell leukemia induced by 1-propyl-1-nitrosourea in Fischer rats

T-cell leukemia was induced at a high rate in female Fischer rats by continuous oral administration of 1-propyl-1-nitrosourea. No association of oncorna viruses were found in the leukemogenesis.

Light and electron microscopic investigations of nasopharyngeal carcinomas with regard to the viral etiology of these tumors

SummaryFive carcinomata of the nasopharynx (four lymphoepithelial carcinomata of the Regaud type and one squamous cell carcinoma) were examined light and electron microscopically. In addition to the familiar histological and cytological features of these tumors, and because of an increased antibody titer against Epstein-Barr virus in all five patients, all those cytoplasmic and nuclear inclusions were examined which could be interpreted as indicative of a virus contact.The following structures were found:Particles and microtubules which correspond in diameter, shape, and location to Corona viruses.Particles surrounded by a double membrane and resembling in form and diameter Oncorna viruses.Tubulo-reticular, coil-shaped cytoplasmic inclusions interpreted as an unspecific reaction of the host cell to viral attack.Spherical nuclear bodies, which are frequently observed in tumors and in viral infections.Intranuclear particles which correspond in diameter, structure, and distribution to viruses of the herpes type such as have been described in cell cultures of Burkitt lymphoma and nasopharyngeal carcinoma. The fifth group particularly was discussed in detail with regard to differentiation between those particles and other structures which could simulate a virus structure.Together with the appearance of increased ribosomes and of particular chromatin distribution within the tumor cell nuclei, the particles we discussed have been interpreted as morphological indications of a virus etiology of the examined tumors.

Biochemical and electron microscopical evidence for the presence of oncorna viruses in spleen tissue from two patients with haematological malignancies.

In extracts of spleen tissue from two patients with haemotological malignancies an RNA dependent DNA polymerase was found in particles with a density of 1.16, that is at the density of oncorna viruses. After treatment with noniomic detergents the enzyme activity was found in particles with a density of 1.23-1.24, similar to the density of oncorna viral cores. A simultaneous detection test with this core fraction material for 70 S RNA and RNA dependent DNA polymerase was positive for both patients. Electron microscopical inspection of the material with a density of 1.16 revealed immature C-type virus like particles, various stages of maturing particles and a number of particles resembling mature C-type oncorna viruses. In two normal spleens from patients with carcinoma of the colon and oesophagus respectively and in three spleens from patients with no history of malignancy no RNA dependent DNA polymerase was found. Material from one normal spleen was examined in the electron microscope and no virus-like particles were seen.

Inhibition of RNA-dependent DNA polymerase of oncorna viruses by Carbopol 934

FEBS LettersVolume 52, Issue 1 p. 141-144 Full-length articleFree Access Inhibition of RNA-dependent DNA polymerase of oncorna viruses by Carbopol 934 H.P.J. Bloemers, H.P.J. Bloemers Department of Biochemistry, University ofnijmegen, Geert Grooteplein Noord 21, Nijmegen, The NetherlandsSearch for more papers by this authorA. van der Horst, A. van der Horst Department of Biochemistry, University ofnijmegen, Geert Grooteplein Noord 21, Nijmegen, The NetherlandsSearch for more papers by this author H.P.J. Bloemers, H.P.J. Bloemers Department of Biochemistry, University ofnijmegen, Geert Grooteplein Noord 21, Nijmegen, The NetherlandsSearch for more papers by this authorA. van der Horst, A. van der Horst Department of Biochemistry, University ofnijmegen, Geert Grooteplein Noord 21, Nijmegen, The NetherlandsSearch for more papers by this author First published: March 15, 1975 https://doi.org/10.1016/0014-5793(75)80657-0Citations: 5AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL References 1 Clercq E. De, P.J. Claes, Biochim. Biophys. Acta, 331, (1973), 329– 332. 2 T.S. Papas, T.W. Pry, M.A. Chirigos, Proc. Natl. Acad. Sci. U.S.A., 71, (1974), 367– 370. 3 W. Braun, W. Regelson, Y. Yajima, M. Ishizuka, Proc. Soc. Exp. Biol. Med., 133, (1970), 171– 175. 4 W. Regelson, Advan. Exp. Med. Biol., 1, (1967), 315– 332. 5 M.A. Chirigos, Comparative Leukemia Research, 36, (1970), 278– 292. Bibl. Haemat. 6 M.A. Chirigos, W. Turner, J. Pearson, W. Griffin, Int. J. Cancer, 4, (1969), 267– 278. 7 I.M. Verma, D. Baltimore, Methods in Enzymology XXIX (1974), Academic Press New York, London 125– 143. 8 H.C. Chopra, G.P. Shibley, J. Nat. Cancer Inst., 39, (1967), 241– 256. 9 D. Baltimore, D. Smoler, Proc. Natl. Acad. Sci. U.S.A., 68, (1971), 1507– 1511. 10 T.H. Maugh, Science, 184, (1974), 970– 974. 11 M. Linial, W.S. Mason, Virology, 53, (1973), 258– 273. Citing Literature Volume52, Issue1March 15, 1975Pages 141-144 ReferencesRelatedInformation

Oncorna-viral information in human glioblastoma.

Two of the main biochemical features characteristic for oncogenic RNA (oncorna) viruses have been detected in human glioblastoma. In all tumors tested so far a RNA instructed DNA polymerase (“reverse transcriptase”) activity was present which exhibited the criteria specific for oncorna viruses. It was stimulable by the synthetic polynucleotide poly-rA: oligo-dT, it was almost insensitive to actinomycin D but very sensitive to ethidiumbromide. Using the simultaneous detection test, a high molecular weight RNA species was found in the subcellular fraction with the highest reverse transcriptase activity.

Cancer and the Ovary

This Presidents Address gives a brief history of the surgical treatment of ovarian cysts and the problems of all cancers are then discussed followed by special reference to ovarian cancers. The immunological defenses of the body to cancer are recognized and the adverse effects of x-ray and some drug therapy on these defenses considered. Recent virus studies have shown that all the viruses involved in transmitting tumors are similar in appearance and genetic structure; all have a long single-stranded molecule of ribonucleic acid. They are known as oncorna viruses and their receptors are very specific even within a given species. Chemical carcinogens may act on cells by being transformed into noxous substances by tissue enzymes; such changes are inherited by future generations of cells after the original carcinogen no longer operates. The most rewarding studies in the future are predicted to be in the immunology chemical oncology and virology areas. Ovarian cancer is often not diagnosed until too late for curative surgery. Abdominal pain and swelling are the most common early symptoms. Postmenopausal bleeding can also occur early in the disease. Laparoscopy is the preferred method of early diagnosis. Ovarian cancer most frequently spreads from the ovarian surface to adjacent structures. Ascites usually indicate dissemination. Cyst rupture at operation justifies additional therapy but may not be as serious as regarded by some. In determining results standardization of histology grading and staging are needed. The stage present at operation is the most important. Radical surgery has been advocated even when the growth is limited to the ovary; however others have found that removing only the diseased ovary in Stage 1 produces equally favorable results. As only about 65% of good risk cases survive 5 years adjuvant therapy is indicated. With surgery and radiotherapy Stage 2 mean survival is 40%; in later stages only 5% have 5-year survival. Chemotherapy has been reported by some as better than radiotherapy. Alkylating agents administered orally or iv seem best. The sensitivity testing of cancer cells is a most optimistic approach and is the best reason for setting up a Central Ovarian Cancer Registry.

Endonucleolytic DNase in oncorna viruses: Role of mycoplasma

The DNA-directed DNA polymerase activity of avian myeloblastosis virus and Rauscher leukemia virus was not enhanced by SV40 DNA, whereas that of murine sarcoma virus preparations was. The latter stimulation is ascribed to an endonucleolytic DNase which occurs in a mycoplasma contaminant. This can be removed by differential velocity centrifugation. Deoxyribonuclease activity is not a property of oncorna viruses, and the possibility is raised that other nonpolymerase enzymatic activities associated with these viruses may be contaminants.

Induction of C-type particles in mammalian cancer cells.

Temin postulated (1,2) that the viral DNA synthesized by the oncorna virion-associated reverse transcriptase (3,4) integrates into the host cell DNA as an essential step in the cellular transformation process. The studies of Hill and Hillova, who demonstrated that permissive cells were transformed by purified DNA molecules from transformed cells (5), confirmed Temin’s hypothesis. Thus, the oncorna virus-transformed cell contains viral DNA sequences in the cellular genome. The mechanism which leads to the integration of the viral DNA molecules into the cellular DNA is not yet known. Also, the cellular mechanisms which control the expression of the viral DNA are not yet understood. In permissive cells, transformation is accompanied by virus production, while in nonpermissive cells transformation occurs but without virus production. These findings suggest that in nonpermissive cells, the transcription of the viral DNA is controlled by the host cell process. Although the viral DNA is repressed in the nonpermissive cells, it was demonstrated (6) that virus synthesis could be induced by fusion of transformed cells with permissive cells. Treatment with 5-bromodeoxyuridine (BUdR) also induced virus replication (7), similar to the effect of arginine deprivation on nonpermissive cells (8). Although the mechanism of virus induction is not understood, the induction of virus replication was used to study the presence of oncorna viruses in cancer cells.

Biochemical and morphological studies of Simian sarcoma virus, type 1

A productive infection has been established in a primary human-embryo fibroblastic cell line (HE) by Simian Sarcoma Virus, Type 1 (SSV-1). The C-type virus particles observed in the HE and marmoset lung cells are similar in morphology. Rate zonal centrifugation and acrylamide-agarose gel electrophoretic analysis of radioactively labeled SSV-1 ribonucleic acid reveal a 60–70-S component which is heat sensitive, as well as 28-S, 18-S, and 4–10-S components, all of which are hydrolyzed by alkali. Studies employing the simultaneous detection assay for viral enzyme and 60–70-S RNA show that the virus has biochemical properties similar to other oncorna viruses.

Structural characteristics of some murine RNA tumor viruses studied by lactoperoxidase iodination.

Iodination by the noninvasive enzymatic lactoperoxidase technique has been used to study the enzyme-accessible and enzyme-inaccessible proteins of three oncorna viruses (radiation leukemia virus, Moloney leukemia virus, and mouse mammary tumor virus). The number and relative molecular weight of proteins associated with virion preparations purified on sucrose gradients were characterized by scans of Coomassie blue-stained bands after dodecyl sulfate-polyacrylamide gel electrophoresis. Gel scans from the leukemia viruses are similar, each showing six distinct major protein bands on stained gels. The mammary tumor virus proteins by this analysis are not similar to those of the leukemia viruses. Enzymatic iodination of intact virion preparations led to the solitary labeling of one of the major proteins of each virus-the 80,000-dalton protein of the leukemia viruses and the 52,500-dalton protein of the mammary tumor virus. These are tentatively positioned as surface (enzyme-accessible) moieties in the virions. Disruption of each virus with a nonionic nonionic detergent before enzymatic iodination led to the labeling of the remaining stainable bands. The four lower molecular weight bands of the leukemia viruses are tentatively positioned as internal (enzyme-inaccessible) components.

Viruses and breast cancer. Introductory remarks.

It has been shown that some breast cancers may have a long preclinic al existence. A host reaction may play a part in determining when preclinical becomes clinical cancer and on the subsequent course of the cancer. A study of breast cancer in mice has shown that it is a systemic disease produced by genetic factors hormones environmental factors and viruses. The virus B particle transmitted by mothers milk is the causative factor if other factors are also present. The virus is present in most organs of the mice including the blood mammary glands and milk long before clinical symptoms of cancer are found. The virus can be found in tumor cells grown in tissue culture but not in other cultured cells. Although the type B particle is regarded as the causative agent in mouse breast cancer its presence does not necessarily indicate future cancer development. However a correlation exists between high numbers of type B particles in milk of mice and a high incidence of breast cancer. Testicular tissues and spermatic fluid also contain virus and may infect the females. The type B particles are known as oncogenic or oncorna viruses. Breast cancers in mice have similarities as well as differences between the findings of neoplasia in women.