Biomedical subjects

T Mariani

Publications and source records attributed to T Mariani.

At least 37 records · Page 2Linked to original sources

PubMed1988

Gene dosage mutants at adenine phosphoribosyltransferase locus induced by colcemid in Chinese hamster V79-AP4 cells.

Pseudodiploid Chinese hamster V79-AP4 cells, functionally diploid at the adenine phosphoribosyltransferase (aprt) locus, were treated with colcemid, a well-known aneuploidizing agent, under various experimental conditions. Aneuploid and tetraploid cells and variants resistant to 10 micrograms/ml of 2,6-diaminopurine (DAP), which selects for presumptive aprt+/- heterozygotes in the untreated cells, were induced. Many of the induced variants were hypotetraploid with three (rather than four) chromosomes carrying the aprt gene. Dot-blot and Southern analysis of the DNA of these clones confirmed that they had three copies of the aprt gene. Their APRT specific enzymatic activity was 60-80% of that of wild-type V79-AP4. The results of these and other experiments suggest that in these variants resistance to DAP is due to an altered aprt gene dosage and point to a possible genetic effect of colcemid and other aneuploidizing agents in somatic mammalian cells.

2-Aminopurine↗

PubMed1988

A genetic analysis of the adenine phosphoribosyl transferase locus in Chinese hamster V79-AP4 cells: relevance to mutagenesis studies.

The chromosomal location of the autosomal locus aprt has been investigated in the permanent Chinese hamster cell line V79-AP4 by standard somatic cell genetics methodologies. Aprt is functionally dizygous in V79-AP4 and the 2 alleles map on 2 chromosome 3 homologs, in agreement with the chromosome assignment of the gene in Chinese hamster primary cells. Chromosome G-banding and a Southern blot analysis of V79-AP4 DNA, using as a probe the cloned Chinese hamster aprt gene, have not revealed any structural alteration at either of the 2 aprt alleles. One of the chromosomes 3 has, however, a terminal deletion in its long arm and is therefore morphologically marked. These findings could make V79-AP4 an interesting cell system for the study of mutational mechanisms at the aprt locus in Chinese hamster.

2-Aminopurine↗

PubMed1987

Multiple congenital anomalies associated with apparently normal maternal intake of vitamin A: a phenocopy of the isotretinoin syndrome?

The teratogenicity of vitamin A has been repeatedly reported in the literature and confirmed on the basis of several cases of adverse pregnancy outcome associated with maternal isotretinoin exposure. We report a case which shows a striking similarity with this syndrome, but the child was born to a mother who took a normal supplementation of vitamin A during pregnancy. The differential diagnosis is discussed.

Abnormalities, Drug-Induced↗

PubMed1987

Analysis by BrUdR-labelling technique of induced aneuploidy in mammalian cells in culture.

To study the origin of induced aneuploid cells, the BrUdR-labelling technique was applied to V79/AP4 Chinese hamster cells treated with colcemid or benomyl. In this way we were able to recognize the cells which had undergone one cellular division after the treatment since their chromosomes exhibited sister-chromatid differentiation. The results showed that the induced aneuploid cells can have either a few or numerous additional chromosomes depending on the concentrations of the drug. Moreover, it could be established that aneuploid cells with numerous additional chromosomes were obtained mainly when polyploid cells were also present in the treated population. This strongly suggests that the excess of additional chromosomes found in the aneuploid cells induced by the highest concentrations may be derived by disturbances of the whole mitotic apparatus rather than by a multiplicity of errors affecting individual chromosomes.

Aneuploidy↗

PubMed1984

Inhibitors of DNA synthesis induce sister chromatid exchanges at the early S phase of the cell cycle.

To investigate the origin of sister chromatid exchanges (SCEs) induced by inhibitors of DNA synthesis, V79/AP4 Chinese hamster cells were treated with aphidicolin, 1-beta-D-arabinofuranosylcytosine, and thymidine. At the end of the treatments we determined both the distribution of the cells in the various phases of the cell cycle and the induction of SCEs. Our data indicate that the cells that were replicating their DNA were arrested at various stages of the S phase. By analyzing the patterns of SCE distribution, we found that the metaphases of the treated cells exhibited either "normal" or enhanced levels of SCEs. Our results suggest that the inhibitors of DNA synthesis induce SCEs in the cells in early S phase probably by activation of potential replicative origins.

Animals↗

PubMed1982

Effect of cocultivation on the levels of spontaneous and induced sister chromatid exchanges in Chinese hamster cells.

The level of sister chromatid exchanges, both spontaneous and induced by UV light or ethylmethanesulphonate (EMS), in Chinese hamster V79/AP4 cell line, is partially reduced upon cocultivation with human cells. Normal and xeroderma pigmentosum (XP) cells are equally effective. On the basis of these observations, cocultivation may represent a good tool for investigating the SCE's formation processes.

Animals↗

PubMed1982

Thioguanine resistance, ouabain resistance and sister chromatid exchanges in V79/AP4 Chinese hamster cells treated with potassium dichromate.

The biological activity of potassium dichromate (K2Cr2O7) was assayed in V79/AP4 Chinese hamster cells by measuring two mutational end points, thioguanine (TG) resistance and ouabain (OUA) resistance, and two non-mutational end points, cytotoxicity and sister chromatid exchanges (SCE). By exposing the cells for 1 h to the chemical, all biological end points examined were affected by the treatment in a dose-dependent manner. Moreover the combined use of the two selective systems indicated that chromium induces base-pair substitutions in mammalian cells in culture.

Animals↗

PubMed1982