A database containing qualitative information on the genotoxic activity of about 3000 chemicals is described. The initial aim for the construction of the database was to develop an instrument for comparing the performance of different genotoxicity assay systems. One application of the database is the prediction of expected results in any genotoxicity assay for chemicals that were tested in a sm...

Evaluation of chromatid aberrations induced in culture by DNA cross linking agents provides the most reliable method currently available for the diagnosis and exclusion of Fanconi's anaemia. However, at appropriate concentrations of clastogenic agent the aberration frequency in an unaffected subject may be very low and thus it may be difficult to confirm that the treatment was effective. Data a...

A multisubunit protein complex, termed cohesin, plays an essential role in sister chromatid cohesion in yeast and in Xenopus laevis cell-free extracts. We report here that two distinct cohesin complexes exist in Xenopus egg extracts. A 14S complex (x-cohesin(SA1)) contains XSMC1, XSMC3, XRAD21, and a newly identified subunit, XSA1. In a second 12.5S complex (x-cohesin(SA2)), XSMC1, XSMC3, and X...

It is becoming clear that reduced chromosome cohesion is an important factor in the rise of maternal age-related aneuploidy. This reduction in cohesion has been observed both in human and mouse oocytes, and it can be measured directly by an increase with respect to maternal age in interkinetochore (iKT) distance between a sister chromatid pair. We have observed variations in iKT distance even i...

A brief description of chromosome aberrations and sister chromatid exchange (SCE) as cytogenetic endpoints for evaluation of DNA damaging agents is presented. Problems associated with the use of cytogenetic assays as population monitors of radiation and chemical exposures are discussed. Adequate cell sample size requirements and accurate assessment of cummulative exposure effects with increasin...

Two sister species of Loneura, from Valle del Cauca, Colombia, are here described and illustrated. They constitute a new species group that modifies the scheme of classification, proposed earlier for the genus by García Aldrete et al. (2011b). The new group is characterized by having the central sclerite of the male hypandrium with four posterior projections. A key to the males of Group II is i...

Ms. Habtegiris had little money and no health insurance. On Dec. 1, hospital authorities notified her brother that unless another hospital could be found to treat his sister, Baylor would be forced to discontinue care after 10 days. But even with Baylor's assistance, the family was unable to find a willing hospital. True to its word, Baylor disconnected her ventilator on Dec. 12, invoking a law...