Blood transport method for chromosome analysis of residents living near Semipalatinsk nuclear test site.

A study was conducted to compare the storage conditions and transportation period for blood samples collected from residents living in areas near the Semipalatinsk nuclear test site (SNTS). Experiments were performed to simulate storage and shipping environments. Phytohaemagglutinin (PHA)-stimulated blood was stored in 15-ml tubes (condition A: current transport method) in the absence or in 50-ml flasks (condition B: previous transport method) in the presence of RPMI-1640 and 20% fetal bovine serum (FBS). Samples were kept refrigerated at 4 degrees C and cell viability was assessed after 3, 8, 12 and 14 days of storage. RPMI-1640, 20% FBS and further PHA were added to blood samples under condition A in 50-ml flasks for culture. Whole-blood samples under condition B were directly incubated without further sub-culturing process, neither media nor PHA were added, to adopt a similar protocol to that employed in the previous transport method. Samples in condition A and condition B were incubated for 48 hr at 37 degrees C and their mitotic index was determined. The results showed that viable lymphocytes were consistent in both storage conditions but the mitotic index was higher in condition A than in condition B. Although further confirmation studies have to be carried out, previous chromosomal studies and the present experiment have shown that PHA-stimulated blood could be stored without culture medium for up to 8 days under condition A. The present results will be useful for cytogenetic analysis of blood samples that have been transported long distances wherever a radiation accident has occurred.

Characterization of late-arising chromosome aberrations in human B-cell lines established from alpha-ray- or gamma-ray-irradiated lymphocytes.

To clarify the characteristics of late-arising (delayed) chromosome aberrations after irradiation in human lymphocytes, 30 B-cell lines were established from the peripheral blood from a healthy adult donor, the lymphocytes of which were exposed to alpha-rays or gamma-rays and then used for experiments. Chromosome aberrations were serially observed at several passages by both conventional cytogenetics and fluorescence in situ hybridization analysis using subtelomere probes. These B-cell lines derived from lymphocytes with a history of radiation exposure had higher percentages of delayed chromosome aberrations, such as dicentrics, rings, endoreduplication, hyperdiploid, hyperploidy, and telomere association. Furthermore, alpha-ray exposure induced higher chromosome instability than gamma-ray exposure, indicating that delayed chromosome aberrations were related with radiation quality. Chromosome instabilities were also observed at the subtelomere. Cell lines showing high chromosome instability had high DNA-PK activity, low expressions of Ku70, p53, and TRF1 proteins after stimulation with radiation. These results indicate that mechanisms underlying delayed chromosome aberrations might be epigenetic, and multiple factors such as defects of DNA-PK, subtelomere, and telomere might be associated.