P Guzzie

Pfizer Inc., New York, New York, United States

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Publications (2)5.59 Total impact

  • M Schuler · P Muehlbauer · P Guzzie · DA Eastmond
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    ABSTRACT: The cytokinesis block in vitro micronucleus (MN) assay in combination with CREST staining and fluorescence in situ hybridization (FISH) with chromosome-specific DNA probes allows mechanistic information on the induction of numerical chromosomal aberrations to be obtained through a rapid and simple microscopic analysis. These techniques can now be used to investigate relationships between the induction of chromosomal loss, non-disjunction and polyploidy by aneuploidy-inducing agents. In the present study, we treated 72 h cultured lymphocytes for the last 24 h of culture with various concentrations of the cough medicine noscapine hydrochloride (NOS) (3.9-120 micro g/ml) in the presence of either cytochalasin B (CYB) (3 micro g/ml) or 5-bromo-2'-deoxyuridine (BrdU) (1 micro M). Using the CREST staining modified MN assay in the CYB-treated cultures, we detected significant increases in CREST-positive but not CREST-negative MN in both binucleated and, to a lesser extent, mononucleated cells, demonstrating the ability of this compound to induce chromosomal loss. In addition, using FISH with chromosome 1- and 9-specific classical satellite probes, a significant induction of chromosomal non-disjunction in the binucleated lymphocytes and polyploidy in the mononucleated lymphocytes was seen, indicating that polyploidy induced by NOS may occur without progression through a normal anaphase and/or telophase. In the BrdU-treated cultures, a dose-dependent induction of hypodiploidy, hyperdiploidy and polyploidy was observed using FISH with a chromosome 9-specific alpha-satellite probe in the labeled cells. By comparison, in the unlabeled non-cycling cells, only a slight increase in hyperdiploidy/polyploidy but not hypodiploidy was seen. A comparison of the effects seen at different concentrations shows that at the lower effective concentrations, all three types of numerical aberrations, chromosomal loss, non-disjunction and polyploidy, contributed to the numerical aberrations seen, whereas at the highest concentration tested, polyploidy was the predominant alteration. These studies indicate that FISH in combination with CYB or BrdU immunfluorescent staining can be sensitive tools for the identification of aneuploidy-inducing agents.
    No preview · Article · Jun 2003 · Mutagenesis
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    M Schuler · P Muehlbauer · P Guzzie · DA Eastmond
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    ABSTRACT: Noscapine hydrochloride is a centrally acting antitussive opium derivative widely used in cough suppressants. Recent studies have reported that noscapine is a potent inducer of polyploidy but not of aneuploidy in vitro. To obtain more comprehensive information about the cytogenetic effects of this compound, we treated cultured human lymphocytes (HPL) and Chinese hamster ovary (CHO) cells with various concentrations of noscapine hydrochloride. Using a differential staining technique noscapine was shown to disrupt the mitotic spindle at concentrations < 5 micrograms/ml in both cell types. The use of multicolor fluorescence in situ hybridization (FISH) on noscapine-treated human lymphocytes showed a dose-dependent induction of hyperdiploidy of chromosome 1 but not of chromosomal breakage in the 1cen-q12 region under in vitro conditions, indicating that noscapine is specifically inducing numerical chromosomal aberrations. FISH with probes targeting different chromosomes revealed that noscapine is capable of inducing both polyploidy and true hyperdiploidy. Our results show that noscapine, by disrupting the function of the mitotic spindle, has the ability to induce aneuploidy and not uniquely polyploidy as previously reported. By using these types of molecular cytogenetic techniques, it should be possible to evaluate the ability of noscapine to induce aneuploidy in the upper intestinal tract in vivo.
    Preview · Article · Jan 1999 · Mutagenesis

Publication Stats

31 Citations
5.59 Total Impact Points

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  • 1999-2003
    • Pfizer Inc.
      New York, New York, United States