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Diamond-Blackfan Anemia
Published in Stephen A. Feig, Melvin H. Freedman, Clinical Disorders and Experimental Models of Erythropoietic Failure, 2019
Jeffrey M. Lipton, Blanche P. Alter
Peripheral blood lymphocyte chromosomes are essentially normal in patients with DBA.50 One patient had an achromatic area on chromosome 1,97 and another had a pericentric inversion in l.107 Three of six patients in one series had an enlarged chromosome 16,76 and one patient had breaks and endoreduplication of chromosome 16.108 One patient had increased spontaneous and X-ray-induced chromosome breakage, without increased breakage due to mitomycin C.109 Others found no increased breakage with diepoxybutane.66,67 More than 50 patients had normal chromosomes, including 20 of our own cases.50 Sister chromatid exchange is also normal.110 Although some DBA patients may have physical findings resembling Fanconi’s anemia, the chromosome studies are clearly distinctive.
Genotoxic effects of gadobutrol and gadoversetamide active substances used in magnetic resonance imaging in human peripheral lymphocytes in vitro
Published in Drug and Chemical Toxicology, 2022
Ece Akbas, Fatma Unal, Deniz Yuzbasioglu
In another preclinical study, a CAs assay in CHO cells was carried out to estimate the genotoxic potential of gadoversetamide active substance. In cells treated with gadoversetamide in the range of 630–5 000 μg/mL, especially at 5 000 μg/mL, specifically the frequency of numerical chromosome abnormalities and the number of endoreduplication significantly increased in both the 24 and 48 h treatments. It was also reported that there was a significant increase in various structural chromosome abnormalities at 5 000 μg/mL in the 24 h treatment (Wible et al. 2001). In the present study, 14 000, 28 000, 56 000, and 112 000 μg/mL concentrations of gadoversetamide administered to PBLs in vitro conditions induced a significant increase in both the abnormal cell frequency and CAs/Cell. At 7 000 μg/mL, the closest concentration to the previous one, increasing in CAs was not at a significant level. These differences might have resulted from the differences in cell types and concentrations used in these two studies.
DNA topoisomerases as molecular targets for anticancer drugs
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2020
Kamila Buzun, Anna Bielawska, Krzysztof Bielawski, Agnieszka Gornowicz
Among Archaea topoisomerase VI causes relaxation of positively and negatively supercoiled DNA and is also involved in DNA replication and transcription. Initiated by the type IIB topoisomerases changes in DNA topology by the formation of breaks in double-stranded DNA occurs with a shift of 2-bp rather than 4-bp as in type IIA topoisomerases57. Recently, topoisomerase VI has been identified in the plant kingdom55,56,59, including red and green algae60. Occurring in plants, Top VI plays an important role in the DNA endoreduplication process. Proper DNA endoreduplication is essential to maintain the correct size of plant cells and consequently the normal size of the entire plant61.
Placental Pathology in Beckwith–Wiedemann Syndrome According to Genotype/Epigenotype Subgroups
Published in Fetal and Pediatric Pathology, 2018
Lucie Gaillot-Durand, Frederic Brioude, Claire Beneteau, Frédérique Le Breton, Jerome Massardier, Lucas Michon, Mojgan Devouassoux-Shisheboran, Fabienne Allias
EVT cytomegaly was found in just over a fifth of patients herein. Armes et al. [15] were the first to describe EVT atypia in BWS placentas; however, we prefer to use the term EVT cytomegaly as atypia means a predisposition to malignant transformation. The present study reports an additional 13 cases of EVT cytomegaly. When present, this microscopic feature was usually diffuse. Interestingly, there were morphological similarities between EVT cytomegaly and adrenal cytomegaly classically observed in BWS, which also demonstrates nuclear gigantism, hyperchromasia, and occasional nuclear pseudoinclusions but no mitotic figures. Although not statistically significant, EVT cytomegaly was more frequent among patients with ICR2 LOM and CDKN1C mutations, both of which implicate CDKN1C that encodes the CDKN1C/p57Kip2 protein, whereas this gene is not disturbed in ICR1 GOM. These results are concordant with a previous observation of cytomegaly in two of three ICR2 LOM cases [15]. Additionally, Armes et al. [15] described nuclear loss of p57 expression in enlarged atypical trophoblasts in two of their cases. We found loss of p57 expression and increased Ki67 proliferating index in EVT cytomegaly, indicating that these dysmorphic changes may be due to repeated cell cycle progression. We hypothesized that endoreduplication (characterized by multiple S-phases without mitosis and cytokinesis, large cells with giant nucleus containing multiple copies of their genome) [39] induces EVT cytomegaly in such cases. This hypothesis was supported using FISH analysis demonstrating polyploidy. Interestingly, EVT cytomegaly is uncommon in placental pathology; hence, it could be of great interest to add this microscopic finding as a cardinal feature in future scoring system for clinical diagnosis proposed by international consensus group [4].