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Biomedical subjects

A Rocchi

Publications and source records attributed to A Rocchi.

At least 55 records · Page 3Linked to original sources
PubMed1988

Synergistic effect of DAPI and thymidylate stress conditions on the induction of common fragile sites.

When supplied to human leukocytes grown in complete medium (RPMI 1640), DAPI, a nonintercalating compound specific for the AT bases of DNA, induces the appearance of three common fragile sites (CFRA) mapped at 1q42, 2q31, and 7p22. The same treatment with DAPI in a medium deficient in folic acid and thymidine (199 M) considerably increases the expression of these sites and induces the appearance of a further 16 CFRA sites at 1q24, 2p25, 4p16, 4q25, 5p15.3, 6p21.3, 6p25, 6q13, 9p24, 16p13.3, 16q23, 17q21, 18q23, 20q13.1, 21q21, and Xq28. The results point to the existence of a synergism between DAPI and thymidylate-stress culture conditions in inducing site-specific chromosome damage. The results also agree with the hypothesis that DAPI-induced CFRA sites are DNA late-replicating chromosomal areas rich in AT bases.

Cells, Cultured↗
PubMed1986

DAPI-inducible common fragile sites.

DAPI, a compound specific for the AT bases of DNA, causes gaps and breaks in three human chromosome sites, at the 1q41-1q42 interface, 2q31, and 7p22. It also induces undercondensation of a chromosome site at the 13q21-13q22 interface. The first three sites have the characteristics of "common fragile sites" and are present as gaps and breaks on the chromosomes of seven individuals.

Base Sequence↗
PubMed1979

Effects of distamycin A on human leukocytes in vitro.

Distamycin A, an oligopeptide antibiotic, supplied at various concentrations for 24 h to human leukocytes in culture, has induced the appearance on some chromosomes of specific areas lacking spiralization. In particular, the centromeric regions of chromosomes 1, 3 and one C-group chromosome and the distal part of the long arm of the Y chromosome were despiralized. The possible nature of these regions is discussed.

Cells, Cultured↗
PubMed1979

Effects of DAPI on human leukocytes in vitro.

DAPI (4'-6-diamidino-2-phenylindole), a fluorochrome specific for AT-rich DNA, was supplied for 24 h at various concentrations to human leukocytes in culture. This treatment caused the appearance on the chromosomes of specific areas lacking spiralization. In particular, the centromeric regions of chromosomes 1,9, and 16, a short region on the long arm of chromosomes 1 and 2, and the distal heterochromatic part of the long arm of the Y chromosome were despiralized. The despiralization pattern of DAPI is compared with those previously obtained with Hoechst 33258 and Distamycin A.

Bisbenzimidazole↗
PubMed1978

Ag staining of the nucleolus organizer (NO) and its relationship to satellite association.

The frequency of involvement in satellite association and the frequency of selective staining of the secondary constrictions with silver solutions have been studied in five phenotypically normal individuals, all carriers of morphological variants of the nucleolus organizing region (NOR). The results show the preferential involvement of some morphological markers in satellite association, and also their preferential staining with Ag-I. It has also been shown that acrocentric chromosomes involved in satellite association are always stained by silver.

Cell Nucleolus↗
PubMed1977

Nucleolus organizer and N-band distribution in morphologic and fluorescence variants of human chromosomes.

Three cases of morphologic variants of human D- or G-group chromosomes have been studied by N- and Ag-AS banding techniques. The results confirm our previous findings about the localization of nucleolus organizers on the secondary constrictions of acrocentric chromosomes. Preliminary results on the distribution and number of N bands in D- and G-group chromosomes with morphologic and fluorescence variants are reported.

Cell Nucleolus↗
PubMed1977

N-banding and nucleolus organisers in Asellus aquaticus (Crust. Isop.).

The N-banding technique was used to stain the nucleolus organiser of the karyotype of Asellus aquaticus (crust. Isop.). Observations were made on the morphological expression of nucleolus organisers as secondary constrictions and the presence of nucleoli in mitotic prophase. An attempt was made to correlate the various results and it seems likely that N-banding is not a reflection of NO activity.

Animals↗
PubMed1976

Nucleolus organizer and satellite association in a variant D-group chromosome.

A No. 15 chromosome with a short arm longer than usual is observed in two phenotypically normal brothers. This chromosome appears to have no visible satellite, shows no N-band staining, and is never involved in satellite association. These results have led us to the conclusion that this chromosome lacks the nucleolus organizer region.

Cell Nucleolus↗
PubMed1976

Effect of Hoechst 33258 on Chinese hamster chromosomes.

Cells of the Chinese hamster strain C-125 were treated for different time intervals with H 33258, a bibenzimidazole derivative. The same compound was used to stain fixed cells of the same strain. H 33258 induced in cells in culture specific areas of reduced spiralization on the metaphase chromosomes of some cells. These probably correspond to DNA segments rich in A-T bases interspersed along the chromosomes. Probably H 33258 acts during S period of cell cycle. The banding obtained by staining with H 33258 is similar to that induced by quinacrine dihydrochloride but shows a better resolution.

Adenine Nucleotides↗
PubMed1976

Effects of Hoechst 33258 on human leukocytes in vitro.

The benzimidazole derivative Hoechst 33258 was added at various concentrations to human leukocyte cultures. After 16 or 24 h of treatment, with concentrations equal to or greater than 100 mug/ml of Hoechst 33258, a number of chromosomes showed regions in which the chromatin was undercontracted. The centromeric regions of chromosome 1 and, more rarely, of chromosomes 3 and 9 appeared to be decondensed. Short decondensed regions were also present on the long arms of chromosomes 1 and 2. The possible nature of these regions is discussed.

Benzimidazoles↗