Eight-year follow-up study of three individuals accidentally exposed to (60)Co radiation: Chromosome aberration and micronucleus analysis

Cytogenetic follow-up of an individual after accidental exposure to industrial radiation using dicentric frequency in blood lymphocytes

A radiation accident occurred in Bursa, Turkey, in July 2005. An industrial radiographer was exposed to industrial iridium-192 gamma rays for 5 h while laying the natural gas line. After 5 h, the victim had a break because of vomiting and nausea. He ended his work, considering that he might have been exposed to radiation. In a few days, erythema, pain, desquamation, edema started in both hands of the victim. The biological dose assessment was started based on frequencies of dicentrics and rings in peripheral blood lymphocytes ten days after the radiation accident. 6 repeated blood samples were taken for 9 years and analyzed staining after giemsa. After 9 years, decline at dicentric frequencies is significant, but still, dicentric contain cells were detected, which were a strong indicator for external radiation exposure.

Cardiovascular Prevention: Migrating From a Binary to a Ternary Classification

Migrating from a binary approach to risk assessment to a ternary model of disease identification allows for individualized, optimal disease management. Redefining the disease/inflammatory approach has been proven to identify, stabilize, and regress atherosclerosis while adding understanding to the progression of vascular disease. Our previously published results show the beneficial effect of comprehensive, evidence-based management on subclinical atherosclerosis and vulnerable plaque. We argue that this approach does not mitigate the value of utilizing standard risk factor identification, but rather augments it for the benefit of the individual patient.

Uranium concentration in umbilical cord may increase the risk for orofacial clefts

BACKGROUND

Orofacial clefts (OFCs) are common kind of congenital malformations. The teratogenicity of uranium (U) has been documented in animal study that maternal exposure to U can increase incidence of external malformations including cleft palate. However, there is limited evidence of the association of in utero exposure to U with OFCs risk in humans.

OBJECTIVE

This study aimed to investigate the association between in utero exposure to U and the risk of OFCs and its subtypes.

METHOD

All subjects were from a case-control study in Shanxi Province, northern China. Eighty-four OFCs cases and 142 healthy controls were included in this study. We used U concentration in umbilical cord as biomarkers to represent intrauterine exposure, which was detected by inductively coupled plasma mass spectrometry. Unconditional logistic regression was used to investigated the association between U level and the risk of OFCs and its subtypes.

RESULTS

The median of U concentration in umbilical cord is 0.745 ng/g in case group and 0.455 ng/g in control group. When the U concentration was divided into two categories, high level of U exposure increased the risk of OFCs (OR: 2.08, 95% CI: 1.13-3.86) and its subtype cleft lip with cleft palate (CLP) (OR: 2.72, 95% CI: 1.21-6.14). When divided into three categories, high level of U elevated the risk for OFCs (OR: 2.40, 95% CI: 1.14-5.06) and CLP (OR: 3.04, 95% CI: 1.20-7.74). Meanwhile, a dose-response relationship between the U concentration and the risk of total OFCs (P for trend = 0.009) and CLP (P for trend = 0.007) was found.

CONCLUSION

Our study found that in utero exposure to high level of U was associated with increased risk of OFCs and its subtype CLP.

Laboratory Intercomparison of Cytogenetic Dosimetry Among 38 Laboratories in China

A nationwide intercomparison exercise for estimating the irradiated dose was organized by the National Institute for Radiological Protection, Center for Disease Control and Prevention of China. Thirty-eight laboratories participated in this program. The main objective of this intercomparison exercise was to compare the participants’ ability of operation and dose assessment basing on the frequencies of dicentrics and centric rings. Whole blood samples were irradiated with different dosages of ⁶⁰Co γ-rays. Each laboratory collected 2 blind samples and prepared the slides independently. All participants presented the estimated dose reports within 30 days. The doses assessed by the participants were acceptable within the reference dose of ±20%. The mean absolute difference of estimated dose relative to the reference dose was calculated, which reflected the overall accuracy of dose estimates for each laboratory. The overall estimation results of blind blood samples for intercomparison showed a good agreement with the reference dose for each sample, with nearly 75% of the participants producing acceptable results.

Measurement of γ-H2AX foci, miRNA-101, and gene expression as a means to quantify radiation-absorbed dose in cancer patients who had undergone radiotherapy

Radiological accidents and nuclear terrorism pose an increased threat to members of the public who, following such an event, would need to be assessed for medical care by fast triage. Assay methods such as chromosome aberrations (CA), cytokinesis-block micronucleus (CBMN) and fluorescence in situ hybridization (FISH) techniques have been well established for dose estimation and their potential for handling more samples has also been proved with automation. However, culturing of lymphocytes is an inevitable step, which limits the potential of these markers for triage. In vitro analysis of gamma-H2AX (γ-H2AX), gene and microRNA (miRNA) markers do not require culturing of lymphocytes, and as such have been suggested as attractive tools for triage. Despite studies reporting in vitro dose-response curves, limited evidence is available evaluating the suitability of these assays in real situations. In this study, we have measured the absorbed dose using γ-H2AX, gene (GADD45A, FDXR, and CDKN1A) and miRNA-101 expression in blood samples of cancer patients (n = 20) who had undergone partial-body radiotherapy and compared with the derived equivalent whole-body doses (EWBD). The obtained results from all patients showed a significant (p < 0.05) increase of γ-H2AX foci in post-irradiated as compared to pre-irradiated samples. Moreover, estimated doses using γ-H2AX foci showed a correlation with the derived EWBD (r² = 0.60, p = 0.0003) and was also shown to be dependent on the irradiated body volume. Consistent with γ-H2AX foci frequency, an increase in fold change expression of genes and miRNA-101 was observed. However, the estimated dose significantly varied among the subjects and showed poor correlation (r² = 0.09, 0.04, 0.01 and 0.03 for GADD45A, FDXR, CDKN1A and miRNA-101, respectively) with EWBD. The overall results suggest that the established in vitro γ-H2AX assay is suitable for the detection of radiation exposure and can also provide an estimate of the dose in in vivo irradiated samples. The genes and miRNA-101 markers showed increased expression; nevertheless, there is a need for further improvements to measure doses accurately using these markers.

Establishment of a γ-H2AX foci-based assay to determine biological dose of radon to red bone marrow in rats

The biodosimetric information is critical for assessment of cancer risk in populations exposed to high radon. However, no tools are available for biological dose estimation following radon exposure. Here, we established a γ-H2AX foci-based assay to determine biological dose to red bone marrow (RBM) in radon-inhaled rats. After 1–3 h of in vitro radon exposure, a specific pattern of γ-H2AX foci, linear tracks with individual p-ATM and p-DNA-PKcs foci, was observed, and the yield of γ-H2AX foci and its linear tracks displayed a linear dose-response manner in both rat peripheral blood lymphocytes (PBLs) and bone-marrow lymphocytes (BMLs). When the cumulative doses of radon inhaled by rats reached 14, 30 and 60 working level months (WLM), the yields of three types of foci markedly increased in both PBLs and BMLs, and γ-H2AX foci-based dose estimates to RBM were 0.97, 2.06 and 3.94 mGy, respectively. Notably, BMLs displayed a more profound increase of three types of foci than PBLs, and the absorbed dose ratio between BMLs and PBLs was similar between rats exposed to 30 and 60 WLM of radon. Taken together, γ-H2AX foci quantitation in PBLs is able to estimate RBM-absorbed doses with the dose-response curve of γ-H2AX foci after in vitro radon exposure and the ratio of RBM- to PBL-absorbed doses in rats following radon exposure.