We obtained strains of yeast with large segments of 2 mu plasmid DNA integrated at several chromosomal locations by selecting genetically for recombination between a chromosomal sequence carried on a 2 mu-circle-containing hybrid plasmid and a homologous sequence on the chromosome. In all diploids examined, the presence of 2 mu circle sequences causes a marked instability of the chromosome into...

We present a prototype software system with sufficient capacity and speed to estimate radiation exposures in a mass casualty event by counting dicentric chromosomes (DCs) in metaphase cells from many individuals. Top-ranked metaphase cell images are segmented by classifying and defining chromosomes with an active contour gradient vector field (GVF) and by determining centromere locations along ...

plasia and treated accordingly. A peripheral blood karyotype performed at 19 years showed two line cells, 45,X/46,XY. The Y chromosome was dicentric, that is, it consisted of two segments coming from two chromatids of the same chromosome.9 Since a karyotype does not always identify the Y chromosome or its fragments, molecular studies or FISH using a Y centromeric probe should be performed in an...

To develop a calibration curve for induction of dicentric chromosomes by radiation, we have used a 60Co gamma-ray source with dose rate of 12.5 mGy/s. Whole blood from 15 healthy donors was collected. Whole blood from each donor was divided equally into 8 parts for exposing to supposedly physical doses 0, 0.30, 0.50, 1.00, 1.50, 2.00, 3.00 and 4.00 Gy for a independent calibration curve. Whole ...

Biological dosimetry, based on the analysis of dicentric chromosomes, is an internationally established, independent method applied in the area of radiation protection. The biodosimetry is mainly performed, in addition to physical dosimetry, with the aim of individual dose assessment, especially after unclear or suspected radiation dose exposures. However, a new biodosimetrical challenge has em...

Biological dosimetry using chromosome aberration analyses in human peripheral blood lymphocytes is suitable and useful tool for estimating the dose when a nuclear or radiological emergency is investigated. Blood samples from five healthy donors were obtained to establish dose-response calibration curves for chromosomal aberrations after exposure to ionizing radiation. In this work, dicentric as...

Armendares, S., Buentello, L., Salamanca, F., and Cantu-Garza, J. M. (1972). A dicentric Y chromosome without evidence of sex chromosomal mosaicism, 46,XYqdic, in a patient with features of Turner's syndrome. Journal of Medical Genetics, 9, 96-100. Caspersson, T., Lomakka, G., and Zech, L. (1971). The 24 fluorescence patterns of the human metaphase chromosomes-distinguishing characters and vari...

The aim of this study was not only to obtain basic technical prerequisites for the establishment of capacity of biological dosimetry at the Ghana Atomic Energy Commission (GAEC) but also to stimulate interest in biological dosimetry research in Ghana and Sub-Saharan Africa. Peripheral blood from four healthy donors was exposed to different doses (0-6 Gy) of gamma rays from a radiotherapy machin...

The Y chromosome is important for male development as it contains the sex determining gene SRY and many spermatogenesis genes. Structural abnormalities of the Y chromosome include rings, deletions, inversions, and dicentrics. 4 These types of abnormalities are common in infertile males (1.5%), especially those with azoospermia. 6 However, such rearrangements are unstable and an additional 45,X ...

We determined that a mutation in the nucleoporin gene NUP170 leads to defects in chromosome transmission fidelity (ctf) and kinetochore integrity in Saccharomyces cerevisiae. A ctf mutant strain, termed s141, shows a transcription readthrough phenotype and stabilizes a dicentric chromosome fragment in two assays for kinetochore integrity. Previously, these assays led to the identification of tw...