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R Toni

Publications and source records attributed to R Toni.

50 records · Page 3Linked to original sources
PubMed1976

Suppression of murine type-C RNA virogenes by type-specific oncornavirus vaccines: prospects for prevention of cancer.

Immunization of crossbred and F1 mice with combined killed and live Gross leukemia virus AKR type-C viral vaccines suppressed endogeneous N-type AKR virus up to 10,000-fold for significant periods during early life. Since several previous studies in the same and similar crossbred systems revealed direct correlations between low and high levels of type-C virus early in life with low and high incidences of leukemia and other cancers later in life, we believe that prospects for suppression of spontaneous neoplasms are good; however, 8-14 months will be required to achieve the final results. Should cancers be prevented by serotype-specific vaccines, such evidence would provide conclusive proof of endogenous viral etiology.

AKR murine leukemia virus↗
PubMed1975

Characteristics of the major internal protein and RNA-dependent DNA polymerase of bovine leukaemia virus.

A virus designated bovine leukaemia virus (BLV), associated with leukaemia in cattle and previously demonstrated to induce the disease in sheep, was purified from chronically infected sheep cell cultures. Electrophoretic analysis showed a major protein of mol. wt. about 24,000 (p24) which reacted in gel diffusion and complement-fixation tests with sera from naturally infected cattle, experimentally infected sheep, and guinea pigs immunized with p24. BLV p24 has an isoelectric point of 8-6. Interspecies antigenic reactivities characteristic of mammalian Type C virus p30s were not detected in disrupted BLV or on p24. Sheep and guinea pig antisera to BLV, reactive with p24, also did not precipitate several Type C virus p30s in radioimmunoassays. BLV is also distinguished from Type C viruses and resembles mouse mammary tumour virus and Mason-Pfezer virus in having an RNA-dependent DNA polymerase which is preferentially active in the presence of Mg++ when synthetic templates are used. Along with previously published morphological data, the above indicates that BLV is not a Type C virus as classically defined. Four hundred and forty one human sera from cancer patients and matched controls were non-reactive with disruped BLV, BLV infected cells, and BLV p24 in complement-fixation tests.

Animals↗
PubMed1973

Mutants of nonproducer cell lines transformed by murine sarcoma viruses. I. Induction, isolation, particle production, and tumorigenicity.

A variety of cell mutants were obtained by a single 5'-bromodeoxyuridine (BrdU) treatment of an nonproducer (NP) cell line transformed by the Kirsten strain of murine sarcoma virus (Ki-MSV). Isolation procedures of these cell See PDF for Structure mutants are described. The cell mutants obtained were classified by tumorigenic potential and shedding of Type C virus particles. The cell mutants were classified into four groups: (A) tumorigenic, without particles; (B) tumorigenic, with Type C particles; (C) nontumorigenic, without particles; and (D) nontumorigenic, with Type C particles. The tumorigenic cell lines showed variability in morphology with both flat and typical transformed appearing cell lines showing equal transplantability.

Animals↗
PubMed1972

Interactions of immunoglobulins G and M in the detection of the mammalian C-type virus cross-reactive antigen.

The mammalian C-type tumor viruses share an antigenic determinant, gs-3, located on the major internal polypeptide of the virion. Detection of this determined in gel diffusion assays by antiserums prepared in rats by immunization with rat tumor homogenates carrying murine virus and serums prepared in a rabbit by immunization with purified murine gs antigen depended on antibodies present in the fractions containing immunoglobulins M and G. The immunoglobulin G fraction by itself precipitated only the homologous murine antigen. Neither fraction alone precipitated heterologous (cat, rat, or hamster) antigen (definition of the gs-3 reaction), while a mixture of the two fractions did. The gs-3 reaction was eliminated by treatment of the serums with beta-mercaptoethanol, also indicating a requirement for immunoglobulin M antibodies.

Animals↗
PubMed1972

Purification and immunological characterization of the major internal protein of the RD-114 virus.

The major internal protein of the RD-114 virus that appeared in a human tumor cell line, RD, after passage through fetal cats was purified by isoelectric focusing and used to prepare antibody in guinea pigs. The protein has a molecular weight of 33,500 in sodium dodecyl sulfate-polyacrylamide gels, and an isoelectric point of 9.1. This contrasts with a molecular weight of 25,000 and an isoelectric point of 8.3 obtained previously for the major protein of cat C-type viruses. The RD-114 protein carries determinants common to all mammalian C-type viruses but not species-specific determinants of cat, mouse, rat, hamster, chicken, and Russell's viper C-type viruses. In addition, two other proteins found in cat virus preparations were not detected in the RD-114 virus. Antiserum to the RD-114 viral protein proved highly specific by complement fixation and gel diffusion assays, and, in addition to the above mentioned mammalian viruses, the antiserum did not react with concentrates of the Woolly monkey or Gibbon ape C-type viruses. These data support the conclusion that the RD-114 virus is a human virus activated by passage through fetal cats. Until additional isolates are made from human cells, the identity of the RD-114 virus as a human C-type tumor virus cannot be fully established; however, this would be highly probable if the species-specific group-specific antigen of RD-114 could be demonstrated in human tumor and/or embryonic tissues.

Acrylamides↗
PubMed1970

Hamster-tropic sarcomagenic and nonsarcomagenic viruses derived from hamster tumors induced by the Gross pseudotype of Moloney sarcoma virus.

Hamster sarcomas induced by the Gross pseudotype of Moloney sarcoma virus yielded a virus sarcomagenic for hamsters but not mice. This virus was able to produce foci on hamster embryo cells, but not on mouse embryo cells. A hamster-tropic nonfocus-forming helper virus was also found in the viral stocks. These hamster-tropic viruses are not immunologically related to the murine viruses in the original inoculum but appear to represent indigenous C-type RNA viruses of the hamster.

AKR murine leukemia virus↗
PubMedDate not supplied

Acromegaly and intestinal neoplasms.

Acromegalic subjects show increased frequency of neoplastic lesions in the colon and rectum with respect to the general population. Recent prospective studies using colonoscopy have shown a 3 time higher prevalence of intestinal polyps and up to 4 time increased presence of colorectal cancer in acromegaly, independently of sex, age, duration of disease and clinical status of the patients. The polyps are distributed throughout the extension of the large bowel and are often multiple, showing at least two different histologic types: hyperplastic and adenomatous. Sometimes they are associated with intestinal carcinomas. Pancolonoscopy is the procedure of choice for the diagnosis of large bowel neoplasms, even though it may be difficult to complete in these subjects because of the frequent presence of an enlarged and elongated colon. It shows a higher sensitivity and specificity compared to other tests such as the barium enema, fecal occult blood test and serum levels of carcinoembryonic antigen. Therefore, it is recommended to follow up acromegalic patients using pancolonoscopy to obtain early detection of neoplastic lesions in the large bowel.

Acromegaly↗
PubMedDate not supplied

Accessory ultrasonographic findings in chronic liver disease: diameter of splenic and hepatic arteries, fasting gallbladder volume, and course of left portal vein.

We have assessed the incidence and significance of changes in the caliber of the splenic and hepatic arteries, in fasting gallbladder volume, and in the intrahepatic course of the left portal vein in a group of 46 patients affected by chronic liver disease (24 with chronic active hepatitis and 22 with liver cirrhosis). Thirty normal subjects were examined as a control group. Mean diameters of the splenic and hepatic arteries were significantly greater in cases of liver cirrhosis than in the control group. In the case of chronic active hepatitis, only the splenic artery proved significantly enlarged in comparison with the control group. These results demonstrate that caliber modification occurs in the splenic and hepatic arteries during chronic liver disease. In particular, changes in the splenic artery precede the onset of clinically evident portal hypertension. Gallbladder volume was significantly increased in patients affected by liver cirrhosis. Finally, statistical analysis did not reveal any significant difference in the angles formed by the transverse and longitudinal tracts of the left portal vein in controls and in subjects with liver disease.

Adult↗