Evaluation of genetic alterations in inhabitants of a naturally high level background radiation and Kudankulam nuclear power project site in India.

Evaluation of genetic alterations in inhabitants of an area of Tamil Nadu, India, chronically exposed to high background radiation (HBRA), was the major purpose of the present study. A total of 216 samples (exposed inhabitants, 108; control subjects, 108) were selected based on the confirmation of radiation dose level using thermoluminescence dosimetry (TLD). After signing a consent form, volunteers provided blood samples (5 ml each) to establish cell cultures at 52 h. One hundred complete metaphase cells from each subject were evaluated for karyotyping. The frequencies of chromosomal alterations (CA) were found to be higher in the exposed groups and the aberrations predominately observed were of chromatid-type. Smoking was found to have considerable effect on the frequency of CA in exposed subjects. With the comet assay for DNA damage, a significant increase in comet tail frequency was also observed in exposed subjects compared to controls. At present there are no radioepidemiological data regarding the cytogenetic studies in these areas. Furthermore, the Kudankulam nuclear power plant nuclear power plant is being constructed in the same area. The study gives potentially important information on the general health effects due to radiation exposure and increases people's understanding of the hazardous nature of chronic low level natural radiation exposure. However, we may conclude that the HBRA by itself does not pose any significant risk of genetic damage as measured by conventional cytogenetic analysis.

Evaluation of the genetic alterations in direct and indirect exposures of hexavalent chromium [Cr(VI)] in leather tanning industry workers North Arcot District, South India.

PURPOSE: The focal aim of the present study was to identify the genetic alterations occurring in the tannery workers and surrounding inhabitants chronically exposed to hexavalent chromium [Cr(VI)]. METHODS: A total of 108 samples which includes 72 exposed subjects [36 directly exposed (DE) subjects and 36 indirectly exposed (IE) subjects] and 36 controls were recruited for this study. The exposed subjects and controls were selected based on the Cr level present in air and their urine. Directly exposed subjects were categorized based on their work duration in the tannery industries, whereas the indirectly exposed subjects were categorized based on their year of residence in the place adjacent to tannery industries for more than 3 decades. Controls were normal and healthy. Age was matched for the exposed subjects and controls. The exposed subjects as well as the controls were categorized based on their age (group I, <40 years; group II, >41 years). Cell cultures were established from blood samples (5 ml from each subject) collected from the subjects (exposed subjects and controls) after obtaining informed consent. G-banding (Giemsa staining) of the cultures, micronucleus (MN) assay and comet assay were used to identify the genetic alterations of individuals exposed to Cr(VI) in comparison with the controls. RESULTS: A higher degree of total CA [12 ± 8.49 (21-25 years)] and MN [18.69 ± 7.39 (11-15 years)] was found in DE subjects compared to other groups. In IE subjects, elevated levels of CA [5.67 ± 1.15 (51-60 years)] and MN [25 ± 9.89 (71-80 years)] were observed. As expected, controls exhibited minimal number of alterations. The overall CA frequency due to Cr exposure was significantly different from that of the controls for both chromatid and chromosome type aberrations (P < 0.05 by ANOVA). The MN/1,000 binucleated cells were significantly increased (P < 0.05) in the peripheral lymphocytes of DE and IE subjects in comparison with controls. The mean tail length of comet assay for DE, IE and controls were analyzed. The mean tail length of DE subjects [4.21 (3.21-10.98)] was higher compared to that of IE subjects [3.98 (2.98-11.27)] and controls [3.01 (2.68-9.40)]. CONCLUSION: In conclusion, this work shows a clear genotoxic effect associated with chromium exposure, both directly and indirectly. Our result reinforces the higher sensitivity of cytogenetic assays for the biomonitoring of occupationally exposed populations. There is a strong need to educate those who work with potentially hazardous heavy about its adverse effects and highlight the importance of using protective measures.

Identification of Chromosomal Aberrations by Using Trypsin G-banding in Hepatocellular Carcinoma Patients (HCC) in Tamil Nadu, India.

Hepatocellular carcinoma (HCC) (or liver cancer) is one of the most common human malignancies worldwide. Aetiologically, HCC is closely associated with chronic hepatitis B and C virus infection, cirrhosis and alcohol intake. The objective of the present study was to elucidate the chromosomal abberations (CA) in HCC patients using the trypsin G-banding technique. This study may help in understanding the pattern of the disease and to assess whether these aberrations are associated with HCC susceptibility. The study examined 51 HCC cases and an equal number (n = 51) of age and gender matched cancer-free controls recruited from the hospitals in Tamil Nadu. The HCC cases were grouped depending upon their age into group I (≤ 45 years) and group II (≥ 46 years). The development of effective markers for the detection of HCC could have an impact on cancer mortality and may have significant public health implications worldwide. Subjects were recruited based on their alpha-fetoprotein (AFP) serum level, which is an effective marker for HCC. In the HCC cases, a higher number of chromatid aberrations [group I 13(25.5%) and group II 43(84.3%)] and CA [group I 10(19.6%) and group II 28(54.9%)] were observed. In contrast, controls showed a lower number of chromatid [group I 5(9.8%) and group II 12(23.5%)] and CA [group I 4(7.8%) and group II 9(17.6%)]. In conclusion, the results of this study contribute to the validation of CA as an intermediate end point in carcinogenesis. Because many people are unaware of this lethal disease, this study will raise awareness of this cancer.

Cytogenetic damage in khaini users of Tamilnadu, Southern India

Aim: The smokeless tobacco (ST) has a strong association with the risk of oral leukoplakia (OL), oral submucous fibrosis (OSF) and oral cancer (OC). ST components exhibit genotoxicity and may alter the structure of DNA, proteins and lipids, resulting in the production of antigenicity. In this study, an attempt was made to estimate the cytogenetic damage [chromosomal aberrations (CA) and micronucleus (MN)] in people habituated to consume khaini (ST), which is one of the major forms of tobacco consumption in Tamilnadu, India, and believed to be a major risk factor for OC. Methods: After signing a consent form, volunteers provided blood samples (108 samples from including experimental and control subjects) to establish cell cultures at 52 h. For CA analysis, 100 complete metaphase cells per subject were evaluated. Chromatid- and chromosomal- type aberrations were identified in experimental and control subjects, where the latter showed a very minimal number of CA in age wise manner. Results: Statistically significant results were obtained in experimental subjects when compared to controls as confirmed by chi-square test. Exfoliated cells from the buccal mucosaof Khaini users were examined by using the micronucleus assay. The difference in mean micronucleated cell count for buccal mucosa between cases and controls were significant (p<0.01). Hence, specific biomarkers on cytogenetic endpoints might help in establishing preventive measures to reduce cancer risks. Conclusion: the genotoxic effect of smokeless tobacco should be considered in addition to other known hazards for assessing health risks.