1,2:3,4-Diepoxybutane Induces Multipolar Mitosis in Cultured Human Lymphocytes.

1,3-Butadiene, a colorless gas regularly used in the production of plastics, thermoplastic resins, and styrene-butadiene rubber, poses an increased leukemia mortality risk to workers in this field. 1,3-Butadiene is also produced by incomplete combustion of motor fuels or by tobacco smoking. It is absorbed principally through the respiratory system and metabolized by several enzymes rendering 1,2:3,4-diepoxybutane (DEB), which has the highest genotoxic potency of all metabolites of 1,3-butadiene. DEB is considered a carcinogen mainly due to its high potential as clastogen, which induces structural chromosome aberrations such as sister chromatid exchanges, chromosomal breaks, and micronuclei. Due to its clastogenic effect, DEB is one of the most used agents for diagnostic studies of Fanconi anemia, a recessively inherited disease related to mutations affecting several genes involved in a common DNA repair pathway. When performing Fanconi anemia diagnostic tests in our laboratory, we have observed occasional multipolar mitosis (MM) in lymphocyte cultures exposed to 0.1 µg/ml of DEB and harvested in the absence of any mitotic spindle inhibitor. Although previous studies reported an aneugenic effect (i.e. it induces aneuploidy) of DEB, no mechanism was suggested to explain such observations. Therefore, the aim of this study was to investigate whether exposure to 0.1 µg/ml of DEB is significantly associated with the occurrence of MM. We blindly assessed the frequency of MM in lymphocyte cultures from 10 nonsmoking healthy individuals. Two series of 3 cultures were performed from each sample under different conditions: A, without DEB; B, with 0.1 µg/ml of DEB, and C, with 25 µM of mitomycin C as positive control. Cultures exposed to DEB showed higher frequencies of MM (23 of 2,000 cells) than did the unexposed ones (3 of 2,000 cells).

BCR/ABL1 Transcripts in Healthy Individuals: A Comparative Analysis Between First-Degree Relatives of Patients with Chronic Myelogenous Leukemia and Subjects without Antecedents of the Disease.

BCR/ABL1 transcripts, the molecular hallmarks of chronic myeloid leukemia (CML), have been detected in peripheral blood from healthy individuals. Although CML is a sporadic disease, familial occurrence has been reported. This raises the question of whether there is a hereditary factor related to the etiology of CML. Our aim is to compare the BCR/ABL1 e13a2 and e14a2 transcript frequency in healthy first-degree relatives of families with CML versus individuals from families without CML antecedents. Ninety-eight healthy individuals, sorted into two groups, were studied: a group consisting of 46 first-degree relatives from families having a CML affected, and another with 52 healthy individuals from families without CML antecedents. BCR/ABL1 e13a2 and e14a2 transcripts were detected in mRNA isolated from peripheral blood leukocytes. We observed 28 of 98 individuals positive for at least one BCR/ABL1 transcript: e14a2 was detected in 22, e13a2 in 4, and co-expression was observed in 2 subjects. The positivity rate in relatives of CML cases was 33%, whereas individuals without CML antecedents had a 25% positivity rate, showing no statistical difference. Our results corroborate the presence of e13a2 and e14a2 BCR/ABL1 transcripts in the peripheral blood of healthy individuals, but has not a found familial factor related to the etiology of this rearrangement.

Y-SNP haplogroups related to the Yqh+ heteromorphism in the Mexican northwestern population.

Morphological variation of the Y chromosome has been observed in different populations. This variation is mostly related to the heteromorphic Yq12 band, which is composed of a variable block of constitutive heterochromatin. The Yqh+ heteromorphism has a worldwide frequency of 2.85% and is considered clinically innocuous. The aim of this study was to identify the ancestry of the Yqh+ heteromorphism present in individuals from western Mexico. For this purpose, 17 Y-chromosome single nucleotide polymorphisms were analysed by multiplex polymerase chain reaction and SNaPshot assays. In 28 Yqh+ males, only five haplogroups were observed; with a haplogroup diversity of 0.4841 ± 0.1094, which was less than that observed in a study of unselected Mexican mestizo population. Differences were specifically conferred by the high frequencies of haplogroups R1b1 and P*(xQ,R), and by the absence of the Amerindian haplogroup Q (Q*(xQ1a3a) plus Q1a3a) from the Yqh+ group. This study suggests a post-1492 incorporation for Yqh+ chromosomes into the Mexican northwestern population.