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C Tanzarella

Publications and source records attributed to C Tanzarella.

69 records · Page 4Linked to original sources
PubMed1984

Enhancement of induced sister chromatid exchange and chromosomal aberrations by inhibitors of DNA repair processes.

The effect of post-treatment with inhibitors of DNA synthesis (hydroxyurea, aphidicolin) and repair (caffeine, 3-aminobenzamide) on the frequencies of chromosomal aberrations and sister chromatid exchange (SCE) induced by mitomycin C and decarbamoyl mitomycin C both in Chinese hamster cells and in human lymphocytes in vitro has been studied. The data show that in the case of Chinese hamster and human lymphocytes mitomycin C-treated cells there is an increased frequency of both chromosomal aberrations and SCE after a G2 post-treatment with the inhibitors, while no increase is observed for decarbamoyl mitomycin C-treated cells. Since SCE are DNA synthesis-dependent phenomenon, an increase in the frequency of SCE also in the G2 phase might suggest that after mitomycin C treatment there is a residual DNA synthesis still going on very late in the cell cycle.

Animals↗
PubMed1983

Formation of chromatid-type aberrations in G2 stage of the cell cycle.

CHO cells were treated in G1 stage of the cell cycle with chromosome-breaking agents that act in an S-dependent manner. The cells were challenged in G2 stage, before fixation, with various inhibitors of DNA synthesis or repair. Short-wave UV, mitomycin C, decarbomyl mitomycin and 4-nitroquinoline oxide (4NQO) were used as chromosome-breaking agents. The inhibitors of DNA repair or synthesis used were hydroxyurea, aphidicolin and caffeine. Permeabilization of cells followed by a treatment with Neurospora endonuclease (a treatment to convert DNA single-strand breaks into double-strand breaks) did not have any influence on the frequencies of chromatid aberrations induced by the chemicals used, whereas with the inhibitors the extent of potentiation varied depending on the mutagen and the inhibitor used.

Animals↗
PubMed1982

Evaluation of radiation-induced chromosomal aberrations in human peripheral blood lymphocytes in vitro: result of an IAEA-coordinated programme.

The results of an IAEA coordinated programme on radiation induced chromosomal aberrations in human peripheral blood lymphocytes in vitro are presented. In a master experiment, a whole blood sample from one donor was irradiated with 200 R of X-rays. Different fixation times from 46 to 82 h were used. The progression of cells into mitosis was monitored by BrdUrd incorporation. 14 investigators took part in the scoring of chromosomal aberrations. The main conclusions of this study are: (1) The mean frequencies of aberrations changed with fixation time. (2) The number of cells scored as aberrant by different laboratories was very similar, but there was variability in the number of aberrations scored per aberrant cell. (3) The differences in the frequencies of aberrations between laboratories were minimal when the scoring was restricted to the first major peak of mitotic activity and sufficient cells were scored. It is concluded that using controlled experimentals conditions, human peripheral blood lymphocytes can effectively be used as a reliable biological dosimeter for absorbed radiation dose.

Argentina↗
PubMed1976

Chromosome constitution of in vitro segregated haploid and diploid cells of the mouse.

The composition in segregated haploid sets of paternal and maternal chromosomes has been studied in order to verify whether their composition is uniparental of mixed, fixed or variable. Primary cultures where prepared using kidneys from hybrids of strains of Mus musculus in which the parental chromosomes are distinguishable; the maternal set consists of 20 teleocentric chromosomes, the paternal set of 9 metacentric chromosomes, derived by Robertsonian fusion and 2 telocentrics. Applying Seabright's banding technique, an analysis of segregated haploid and diploid cells, which have originated spontaneously through polyploidisation-segregation processes was carried out. It was concluded that the haploid sets have a variable composition of paternal and maternal chromosomes.

Animals↗
PubMed1975

Chemical induction of chromosome aberrations in somatic cells of Drosophila melanogaster.

Third instar larvae of the Oregon R stock were treated for 25 or 30 min with vapour of methyl methanesulphonate (MMS). At various times after the treatment (4, 8 and 12 h), microscope specimens of the nerve ganglia were prepared. At all the times of fixation, only aberrations of a chromatid type were found, but with different frequencies in the two sexes. The females were about 3 times more sensitive than the males to MMS. An analysis of the distribution of the breaks between and within chromosomes showed that they were not localized at random but were clustered in the heterochromatic centromere regions of the X chromosome and the autosomes. The Y chromosome, although entirely heterochromatic, on the other hand, was highly resistant to MMS. However, this phenomenon had only a very weak effect upon the variation with sex of MMS-induced chromosome damage. Among the aberrations induced, although interchanges were normally present, neither intra-exchanges nor triradials were found. In the interchanges, there was a greater tendency for the homologous chromosomes to be involved, and these rejoined symmetrically. The above results are discussed in relation to data previously obtained with X-rays.

Animals↗
PubMed1974

Analysis of the chromosome aberrations induced by x-rays in somatic cells of Drosophila melanogaster.

A technique has been perfected for enabling good microscope preparations to be obtained from the larval ganglia of Drosophila melanogaster. This system was then tested with X-rays and an extensive series of data was obtained on the chromosome aberrations induced in the various stages of the cell cycle.-The analysis of the results obtained offers the following points of interest: (1) There exists a difference in radio-sensitivity between the two sexes. The females constantly display a greater frequency of both chromosome and chromatid aberrations. They also display a greater frequency of spontaneous aberrations. (2) In both sexes the overall chromosome damage is greater in cells irradiated in stages G(2) and G(1). These two peaks of greater radiosensitivity are produced by a high frequency of terminal deletions and chromatid exchanges and by a high frequency of dicentrics, respectively. (3) The aberrations are not distributed at random among the various chromosomes. On the average, the Y chromosome is found to be more resistant and the breaks are preferentially localized in the pericentromeric heterochromatin of the X chromosome and of the autosomes. (4) Somatic pairing influences the frequency and type of the chromosome aberrations induced. In this system, such an arrangement of the chromosomes results in a high frequency of exchanges and dicentrics between homologous chromosomes and a low frequency of scorable translocations. Moreover, somatic pairing, probably by preventing the formation of looped regions in the interphase chromosomes, results in the almost total absence of intrachanges at both chromosome and chromatid level.

Animals↗
PubMedDate not supplied

Chromosomal aberrations induced by restriction endonucleases.

Restriction endonucleases (REs) are able to induce chromosomal aberrations in Chinese hamster ovary (CHO) cells. The G1 phase of the cell cycle seems to be especially sensitive for the induction of chromosomal aberrations by REs. The different capacities of REs to induce chromosomal aberrations are probably correlated with the number of recognition sites in the genome.

Animals↗