Biomedical subjects

F Ronchese

Publications and source records attributed to F Ronchese.

At least 55 records · Page 3Linked to original sources

PubMed1983

Different susceptibility of BALB/Mo and BALB/c mice to cytogenetic damage induced by urethan.

The urethan-induced clastogenic effect in BALB/Mo mice carrying the Moloney murine leukemia virus (M-MuLV) as an endogenous retrovirus was evaluated by short-term micronucleus assay on bone marrow polychromatic erythrocytes (PCE). A single urethan injection in 3 dose levels brought the incidence of micronucleated PCE far above baseline values when scoring was performed 24 h after treatment; this increase was higher in BALB/Mo than in M-MuLV-free BALB/c mice. In a second experiment, micronucleated PCE incidence was determined as a function of the time interval after a single injection of 1 mg urethan/g of body weight. Higher values of micronucleated PCE were scored in BALB/Mo than in BALB/c mice; statistically significant differences were found at 24 and 48 h after treatment.

Animals↗

PubMed1983

Sister chromatid exchanges and chromosomal aberrations induced by mitomycin C in mouse lymphocytes carrying a leukemogenic virus.

The induction of chromosomal damage (sister chromatid exchanges (SCEs), chromosomal aberrations, and micronuclei) in T lymphocytes from mouse spleen was analyzed after treatment in vivo with different concentrations of mitomycin C (MMC). Lymphocytes were derived from BALB/Mo mice, which carry an endogenous type C retrovirus (Moloney murine leukemia virus, M-MuLV), and from BALB/c mice (controls, M-MuLV-free). Chromosomal damage was determined in vitro on lymphocytes stimulated with concanavalin A (Con A) and incubated for two generation cycles with bromodeoxyuridine (BUdR). The baseline frequency of SCEs was significantly higher in untreated BALB/Mo than in BALB/c lymphocytes. The frequencies of SCEs were significantly increased by increasing doses of MMC in both BALB/c and BALB/Mo T lymphocytes. Treatment with a low dose of MMC (0.3 mg/kg) produced an additive effect on SCE frequency in BALB/Mo lymphocytes, which was gradually suppressed by increasing the MMC concentration (3-5 mg/kg). Indeed, the levels of SCEs became significantly lower in BALB/Mo than in BALB/c lymphocytes at the highest MMC concentration tested (10 mg/kg), indicating that a negative synergistic effect was eventually produced. Chromosomal aberrations (breaks and total aberrations) were significantly increased by the highest MMC doses (5-10 mg/kg) and were more frequent in BALB/Mo than in BALB/c lymphocytes at 10 mg/kg MMC. The frequencies of micronuclei were increased by all MMC doses and were significantly higher in BALB/Mo than in BALB/c lymphocytes at 10 mg/kg MMC. These results are referred to interferences of M-MuLV and MMC with the function of enzymes, such as DNA topoisomerases, involved in the mechanism of SCE production.

Animals↗

PubMed1983

Natural history of M-MSV tumors in mice carrying endogenized Moloney leukemia virus.

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Animals↗

PubMed1983

Induction of DNA repair synthesis by ultraviolet radiation and methylmethanesulphonate in cultured mouse lymphocytes.

The induction of DNA repair synthesis by UV-radiation and methyl-methanesulphonate (MMS) was studied in mouse lymphocytes and leukemic cells by means of autoradiography and scintillation counting, after labelling in vitro with tritiated thymidine ([3H]dThd). Repair stimulation was detected by both procedures in LSTRA and YC8 leukemic cell lines as well as in primary fibroblasts of BALB/c and BALB/Mo mice. No stimulation was observed in primary cultures of lymphocytes from the spleen, thymus and lymph-nodes of the same mice. In primary lymphocytes neither stimulation with concanavalin A (Con A) nor pre-incubation with 5-bromodeoxyuridine (BUdR) were effective in making evident DNA repair. The data put into question the reliability of the repair test for the prediction of carcinogenic potential of chemicals.

Animals↗

PubMed1983