0000000000117604
AUTHOR
Giusi Barbata
Chromosomal abnormalities in Waldenström's macroglobulinemia
We report the results of cytogenetic studies of direct bone marrow (BM) preparations and of short-term BM and peripheral blood (PB) cultures from 17 patients with Waldenström's macroglobulinemia. We noted clonal chromosome changes in 10 patients. Abnormalities affected chromosomes X, Y, 2, 4, 5, 15, 16, 18, 19, 20, 21, and 22; in particular, chromosomes 2, 4, and 5 were involved in structural changes: a homogeneously staining region [hsr(2)], a der(4)t(4;?)(q32;?), and a 5q+. The other chromosomes were involved in numerical abnormalities, such as pseudodiploidy (a 46,X,-X,+15 clone), loss of chromosome Y, and monosomy of chromosomes 16, 18, 19, 20, 21, and 22. Nonclonal chromosome rearrange…
Possible involvement of the IL4 gene in Waldenström's macroglobulinemia
Abstract We report the results of a molecular investigation of 11 patients affected by Waldenstrom's macroglobulinemia, a rare B-cell malignancy characterized by an excessive proliferation of immunoglobulin(Ig)M-secreting plasmacytoid cells. In particular, we studied the interleukin-4 (IL4) gene, which codes for a B-specific growth factor capable of stimulating the proliferation and differentiation of secreting plasma cells. By Southern hybridization, in three patients we found the presence of additional bands in comparison with the expected pattern; moreover, these bands showed a different degree of intensity.
Cytogenetic findings in secondary acute nonlymphocytic leukemia
Abstract We here report the results of cytogenetic studies carried out in eight patients with acute nonlymphocytic leukemia developed after primary neoplasias. In seven of the reported cases, clonal chromosome aberrations were found, some being specific of de novo acute nonlymphocytic leukemia (ANLL). Numerical abnormalities were detected, such as the total monosomy of chromosomes 5, 7, 21, trisomy of chromosomes 8, 11, 15, and duplication of chromosome Y. Structural changes were also observed: a del(12)(p12), a del(16)(q22), the translocations t(3;5)(p21;q35),t(3;7)(p21;q35), and t(12;14)(p12;q32) and other changes involving chromosome 8. The finding of a hypertetraploid karyotype with com…
Genomic instability induced by α-pinene in Chinese hamster cell line.
Here, we report the effects of exposure of mammalian cells to α-pinene, a bicyclic monoterpene used in insecticides, solvents and perfumes. Morphological analysis, performed in V79-Cl3 cells exposed for 1 h to increasing concentrations (25 up to 50 μM) of α-pinene, indicated a statistically significant increase in micronucleated and multinucleated cell frequencies; apoptotic cells were seen at 40 and 50 μM. This monoterpene caused genomic instability by interfering with mitotic process; in fact, 50% of cells (versus 19% of control cells) showed irregular mitosis with multipolar or incorrectly localised spindles. Cytogenetic analysis demonstrated high-frequency hypodiploid metaphases as well…
Arsenic-induced DNA hypomethylation affects chromosomal instability in mammalian cells
Early genetic instability induced in dividing V79-Cl3 Chinese hamster cells by inorganic arsenic, as demonstrated in our previous investigation, was evidenced by aneuploidy and nuclear abnormalities, but not by chromosomal rearrangements. Here we report the results of cytogenetic and morphological analyses performed on the progeny of cells dividing at the end of sodium arsenite treatment after they had been expanded through 120 generations (ASO cells) and then cloned. The acquired genetic instability persisted and was increased by highly unstable chromosomal rearrangements, namely dicentric chromosomes and telomeric associations, which were not seen following acute exposure. A peculiar find…
Complementation among developmental mutants in Aspergillus nidulans.
In heterokaryons between pairs of aconidial mutants of Aspergillus nidulans one of the component strains usually shows a striking prevalance in the contribution to the conidial crop. By assuming that the prevailing strain is blocked earlier and the succumbent one later in the process of differentiation, a series of mutations can be arranged in a consistent order. Some mutant strains do not fit the scheme exactly but show a general tendency to be succumbent to “early” mutants and prevalent over the “late” ones. A criterion for arraying genes involved in differentiation according to the order of their physiological action is proposed.
Biological effects of inorganic arsenic on primary cultures of rat astrocytes
It is well established that inorganic arsenic induces neurotoxic effects and neurological defects in humans and laboratory animals. The cellular and molecular mechanisms of its actions, however, remain elusive. Herein we report the effects of arsenite (NaAsO2) on primary cultures of rat astrocytes. Cells underwent induction of heat shock protein 70 only at the highest doses of inorganic arsenic (30 and 60 microM), suggesting a high threshold to respond to stress. We also investigated arsenic genotoxicity with the comet assay. Interestingly, although cells treated with 10 microM arsenite for 24 h maintained >70% viability, with respect to untreated cells, high DNA damage was already observed…
Acrylamide catalytically inhibits topoisomerase II in V79 cells.
The vinyl monomer acrylamide is characterized by the presence of an alpha,beta-unsaturated carbonyl group that makes it reactive towards thiol, hydroxyl or amino groups and towards the nucleophilic centers in DNA. The ability of acrylamide to chemically modify protein thiols has prompted us to consider topoisomerase II as one possible target of acrylamide, since agents targeting protein sulfhydryl groups act as either catalytic inhibitors or poisons of topoisomerase II. Nuclear extracts from V79 Chinese hamster cells incubated with acrylamide reduced topoisomerase II activity as inferred by an inability to convert kinetoplast DNA to the decatenated form. Nuclear extracts incubated with acry…
Clastogenic and aneuploidizing effects of antiblastic busulphan revealed by kinetochore immunofluorescence in CHO cells.
We utilized, in CHO cells, the cytoplasm preservation technique to evaluate the micronucleus frequency at different busulphan concentrations, and the indirect immunofluorescence technique, using sera obtained from patients with scleroderma (CREST variant), to analyze if busulphan-induced micronuclei have kinetochores. Results show that this alkylating agent is capable of causing a significant increase of micronuclei in vitro, a great part (40%) of them having CREST-positive kinetochores. These findings confirm the clastogenic effect of busulphan and reveal a considerable capability of this agent to induce aneuploidy. These results are examined taking into account the high incidence of secon…
Inherited pericentric inversion of human chromosome 5.
Une inversion pericentrique heterozygote du chromosome 5 a ete decouverte dans les cellules de la moelle osseuse et dans les lymphocytes peripheriques stimules par le phytohemagglutinine d'une femme de 75 ans atteinte de myelofibrose et de metaplasie myeloide. L'inversion etait presente dans 100% des metaphases etudiees. Les points de cessure du chromosome 5 etaient localises en k15 et q10. Une etude de la famille est presentee
Apoptosis in sea urchin embryos.
Abstract It is demonstrated by DNA electrophoresis analysis, morphological observations and TdT in situ reaction, that Paracentrotus embryos if treated with TPA plus heat undergo an apoptotic reaction. Indication is also obtained that non treated embryos undergo spontaneous apoptosis at the early pluteus stage, expecially in the districts of arms and intestine. The possible meaning of this latter observation is discussed.
The DNA methylation inhibitor 5-azacytidine modulates 6-thioguanine toxicity in mammalian cells
In order to assess the effects of combining two antimetabolites used separately to treat human leukemias, we carried out an experimental study by exposing V79 Chinese hamster cells, a 6-thioguanine (6-tG)-sensitive cell line, to sequential and concurrent treatments with 5-azacytidine (5-azaC) and 6-tG. In this paper, we demonstrate that there is a clear dependency for the way in which this combination was tested. Pre-treatment with 5-azaC made V79 cells more resistant to 6-tG by a substantial reduction in 6-tG incorporation into DNA; this effect could still be detected for several cell divisions after the removal of 5-azaC, and was achieved neither by reduced cell growth nor by the inductio…
Early induction of genetic instability and apoptosis by arsenic in cultured Chinese hamster cells
In order to assess at what time from the beginning of exposure inorganic arsenic can give rise to genetic instability and trigger apoptosis, V79-C13 Chinese hamster cells were treated with 10 microM sodium arsenite for 24 h. Under these conditions, cell survival was >70% and cells showed neither an increase in chromosome aberration frequency nor a delay in cell cycle progression. Investigations, which were carried out every 6 h during the treatment, revealed an early appearance of genetically unstable cells, namely micronucleated, multinucleated and mononucleated 'giant' cells, as well as apoptotic cells. Indirect immunostaining using anti-beta-tubulin antibody showed severe alterations in …
“Masked” Philadelphia chromosome resulting from a t(X;22) in chronic myeloid leukemia
Abstract A rare cytogenetic finding in chronic myeloid leukemia is reported. It consisted in a “masked” Philadelphia chromosome, resulting from an unusual translocation between chromosomes #22 and X. The t(X;22) was present in 100% of direct and cultured bone marrow cell preparations. Chromosome #9 did not seem to be involved in the formation of the Ph marker. Involvement of the X chromosome in karyotypic changes of hematologic diseases, with particular respect to chronic myeloid leukemia, is discussed.
Karyotype Abnormalities in a Variant Chinese Hamster Cell Line Resistant to Methyl Methanesulphonate
A variant cell population, isolated from V79-CI 3 Chinese hamster cells after two consecutive treatments with methyl methanesulphonate (MMS), was found to be highly resistant to killing by this alkylating agent. The resistant cell line was cytogenetically characterized both by the presence of a stable translocation involving metacentric chromosome 2 and acrocentric chromosome 6 and by a supernumerary chromosome originated by the duplication of a small telocentric chromosome. This cell population also showed a transient transformed phenotype, seen as formation of transformed foci containing cells with high chromosomes counts and multiple chromosomal aberrations. As MMS-resistance and karyoty…
Spontaneous Endoreduplication, Tetraploidy and Chromosome Breakage in Lymphocyte Cultures from Healthy Subjects
SUMMARY42,703 metaphases of peripheral lymphocytes from 20 healthy subjects (10 women and 10 men) were examined in order to establish the frequency of endoreduplicated cells and of tetraploid cells without diplochromosomes. Frequencies were found to be 0.016% and 0.112%, respectively. The two sexes did not differ as to the frequency of tetraploid cells, with and without diplochromosomes (about 0.13% in either sex). In a total of 2,135 well spread metaphases examined, 26 cells (i.e. 1.2%) with chromosomal breaks were found. Again, no significant differences between the two sexes were found as to such chromosome abnormalities.
Long-Lasting Genomic Instability Following Arsenite Exposure inMammalian Cells: The Role of Reactive Oxygen Species
Previously, we reported that the progeny of mammalian cells, which has been exposed to sodium arsenite for two cell cycles, exhibited chromosomal instability and concurrent DNA hypomethylation, when they were subsequently investigated after two months of subculturing (about 120 cell generations) in arsenite-free medium. In this work, we continued our investigations of the long-lasting arsenite-induced genomic instability by analyzing additional endpoints at several time points during the cell expanded growth. In addition to the progressive increase of aneuploid cells, we also noted micronucleated and multinucleated cells that continued to accumulate up to the 50th cell generation, as well a…
Sister chromatid exchange in Waldenström's macroglobulinemia
Results on sister chromatid exchange (SCE) frequency and interchromosomal distribution in bone marrow and peripheral blood cultures from patients with Waldenström's macroglobulinemia are reported. PHA-stimulated bone marrow cultures showed increased SCE frequencies in all 12 patients examined. The increase was particularly high in two cases (17.07 and 16.77 SCE/cell, respectively) and, in one of them, a very high SCE level was found in PHA-stimulated peripheral blood culture (40.81 SCE/cell). In LPS-stimulated cultures, increased SCE levels were observed in some patients. Comparison between SCE frequency in bone marrow cell cultures with either mitogen showed a significant increase in PHA-s…