Abhay Singh Yadav

The HUman MicroNucleus project on eXfoLiated buccal cells (HUMNXL): The role of life-style, host factors, occupational exposures, health status, and assay protocol

The human buccal micronucleus cytome assay (BMCyt) is one of the most widely used techniques to measure genetic damage in human population studies. Reducing protocol variability, assessing the role of confounders, and estimating a range of reference values are research priorities that will be addressed by the HUMN(XL) collaborative study. The HUMN(XL) project evaluates the impact of host factors, occupation, life-style, disease status, and protocol features on the occurrence of MN in exfoliated buccal cells. In addition, the study will provide a range of reference values for all cytome endpoints. A database of 5424 subjects with buccal MN values obtained from 30 laboratories worldwide was compiled and analyzed to investigate the influence of several conditions affecting MN frequency. Random effects models were mostly used to investigate MN predictors. The estimated spontaneous MN frequency was 0.74‰ (95% CI 0.52-1.05). Only staining among technical features influenced MN frequency, with an abnormal increase for non-DNA-specific stains. No effect of gender was evident, while the trend for age was highly significant (p<0.001). Most occupational exposures and a diagnosis of cancer significantly increased MN and other endpoints frequencies. MN frequency increased in heavy smoking (≥40cig/day, FR=1.37; 95% CI 1.03-.82) and decreased with daily fruit consumption (FR=0.68; 95% CI 0.50-0.91). The results of the HUMN(XL) project identified priorities for validation studies, increased the basic knowledge of the assay, and contributed to the creation of a laboratory network which in perspective may allow the evaluation of disease risk associated with MN frequency.

Increased frequency of micronucleated exfoliated cells among humans exposed in vivo to mobile telephone radiations

The health concerns have been raised following the enormous increase in the use of wireless mobile telephones throughout the world. This investigation had been taken, with the motive to find out whether mobile phone radiations cause any in vivo effects on the frequency of micronucleated exfoliated cells in the exposed subjects. A total of 109 subjects including 85 regular mobile phone users (exposed) and 24 non-users (controls) had participated in this study. Exfoliated cells were obtained by swabbing the buccal-mucosa from exposed as well as sex-age-matched controls. One thousand exfoliated cells were screened from each individual for nuclear anomalies including micronuclei (MN), karyolysis (KL), karyorrhexis (KH), broken egg (BE) and binucleated (BN) cells. The average daily duration of exposure to mobile phone radiations is 61.26 min with an overall average duration of exposure in term of years is 2.35 years in exposed subjects along with the 9.84+/-0.745 micronucleated cells (MNCs) and 10.72+/-0.889 total micronuclei (TMN) as compared to zero duration of exposure along with average 3.75+/-0.774 MNC and 4.00+/-0.808 TMN in controls. The means are significantly different in case of MNC and TMN at 0.01% level of significance. The mean of KL in controls is 13.17+/-2.750 and in exposed subjects is 13.06+/-1.793. The value of means of KH in exposed subjects (1.84+/-0.432) is slightly higher than in controls (1.42+/-0.737). Mean frequency of broken egg is found to be more in exposed subjects (0.65+/-0.276) as compared to controls (0.50+/-0.217). Frequency of presence of more than one nucleus in a cell (binucleated) is also higher in exposed (2.72+/-0.374) in comparison to controls (0.67+/-0.231). Although there is a slight increase in mean frequency of KH, BE and BN in exposed subjects but the difference is not found statistically significant. Correlation between 0-1, 1-2, 2-3 and 3-4 years of exposure and the frequency of MNC and TMN has been calculated and found to be positively correlated.

Evaluation of Genetic Damage in Farmers Exposed to Pesticide Mixtures

Abstract Environment surrounding us is being polluted day by day by various kinds of chemicals and xenobiotics. Pesticides are one such group, which are toxic in nature yet indispensable as they are used in variety of human activities such as agriculture, aquaculture and household tasks. Excessive dependency on these chemicals is a serious concern today. For the present investigation, a total of 62 individuals including 33 pesticide users (exposed) and 29 non-users (controls) gave blood samples. Comet assay being a highly sensitive and low cost technique was used to access the level of genetic damage in exposed population. Hundred cells were analysed from each individual and Damage Index (DI) was calculated using various comet parameters such as comet length, tail length, tail area, percentage DNA in tail, tail moment and olive tail moment. The mean duration of exposure to pesticides in farmers was 14.032 years. The mean value of comet length was 94.96±4.22 in exposed cases as compared to 36.56±2.11 in controls. The mean value of tail length was found to be 52.18±3.74 and 7.01±1.47 in exposed and controls, respectively. The mean value of percentage of DNA in tail in exposed and controls was 27.45±1.64, 9.04±0.67, respectively. The mean tail area was 19.23±4.75 in exposed and 1.39±0.32 in control individuals. The mean tail moment and olive tail moment were found to be 16.91±2.14, 15.58±9.07 in exposed and 1.04±0.032, 1.82±0.32 in case of control individuals. All these comet parameters were found to be statistically significant at 0.005 level using t-test. The percentage of DNA in tail was also found to increase with increase in duration of exposure.

Genomic diversities and affinities among eight endogamous groups of Haryana (India): A study on insertion/deletion polymorphisms

Background: The present study examines genomic variation among eight endogamous groups (Bania, Kamboh, Lobana, Saini, Bishnoi, Sansi, Balmiki and Ramdasia) of Haryana, north-west India. Aim: The present study examines the eight indel polymorphic loci in the population of Haryana. These loci were further used to compare the genomic diversity of the population in relation to other population groups of India. Subjects and methods: DNA samples from 580 unrelated individuals belonging to eight endogamous groups were analysed at eight human-specific insertion/deletion polymorphic loci following standard protocols. Results: All loci, except Alu CD4 and Alu APO, were found to be highly polymorphic. High average heterozygosity values (0.3886 among Kamboh to 0.4276 among Bishnoi) were observed. The overall coefficient of gene differentiation (0.0270) was found to be remarkably close to the Wahlunds variance (0.0258). Comparison with other Indian populations showed that populations of the same geographic region tend to cluster together, irrespective of their social status. Conclusion: In various endogamous groups of Haryana, the time of divergence seems to be too small to reflect the genetic differences between them. It may be possible that gene flow occurred prior to the sub-division into the present endogamous groups or the present populations might have the same sources of genes resulting in a low level of genetic differentiation. Populations of Haryana were found to be more similar with populations of the neighbouring states of Punjab and Uttar Pradesh.

Chromosome Damage in Lymphocytes of Stainless Steel Welders

Abstract Genotoxic effect of welding fumes generated by Manual Metal Arc (MMA), Metal Inert Gas (MIG) and Oxyacetylene welding on the lymphocytes of 75 welders, 25 from each group and equal number of healthy matched controls, was investigated by studying Mitotic Index (MI), Chromosome Aberrations (CAs), Sister Chromatid Exchanges (SCEs), and Satellite Associations (SAs) The MI showed significant increase in all the three groups (4.25 - 7.66, 4.35 - 7.63, 4.63 - 7.54). The background frequency for CAs was normal (0.88, 0.84, 0.92). It significantly increased in all the three groups (4.68, 3.84, 2.96). Among controls only chromatid gaps and breaks were observed, while chromosome type aberrations could not be seen. Among exposed samples both chromatid type viz. gaps, breaks and isochromatid exchanges and chromosome type aberrations viz. dicentrics, rings, acentric fragments, translocations, chromosome gaps, chromosome breaks and diplochromosomes were observed. The frequency of SCEs also increased (3.98 - 7.84, 4.16 - 4.72, 4.57 - 6.43). However, the increase was significant in group-1 and group-3 welders only. Synergistic effect of smoking and alcohol was noticed in both CAs and SCEs, the frequencies being the highest in smokeralcoholics and lowest in non smoker - non alcoholics. The CAs and SCEs also revealed correlation with the duration of exposure. The frequencies of SAs also depicted significant increase (4.8 - 13.8, 5.64 - 11.48, 5.56 - 9.28). The D-G type of associations outnumbered all other types. It is concluded that the welding fumes, containing chromium (Cr VI) and nickel, cause considerable chromosomal damage. The welders, in their occupational settings are prone to high genetic risk.

Genotoxic Effects of Chlorpyrifos in Freshwater Fish Cirrhinus mrigala Using Micronucleus Assay

The genotoxicity of pesticides is an issue of worldwide concern and chlorpyrifos is one of the largest selling organophosphate agrochemicals that has been widely detected in surface waters of India. The studies on long term genotoxic biomarkers are limited; therefore, present study was carried out to analyze the incidence of nuclear anomalies in the blood cells of fresh water fish Cirrhinus mrigala using micronucleus (MN) assay as a potential tool for assessment of genotoxicity. Acute toxicity of chlorpyrifos was evaluated by exposing fingerlings to different doses of chlorpyrifos (1/20, 1/10, and 1/5 of LC 50 ) and LC 50 was calculated as 0.44mg L -1 using probit analysis. Blood samples were taken on days 2, 4, 8, 12, 21, 28, and 35. In general, significant effects for both concentration and duration of exposure were observed in treated fish. It was found that MN induction was highest on day 14 at 0.08mg L -1 concentration of chlorpyrifos. It was concluded that chlorpyrifos is genotoxic pesticide causing nuclear anomalies in Cirrhinus mrigala .

Ultra Violet -B Induced DNA Damage in Human Leucocyte Cells

Abstract The Single Cell Gel Electrophoresis (SCGE) Assay also known as Comet Assay is a rapid, simple and visual technique for assessing DNA damage in individual cells. Effect of UV-B was studied by irradiating human leucocytes. Irradiation of leucocyte increases the DNA instability, which can be assessed by Single Cell Gel Electrophoresis Assay. The blood samples were exposed to UV-B radiation for various time period and a correlation was found out between length of the comet tail and time period of exposure to UV radiation. The UV-B irradiation showed clear-cut dose effect relationship. It was observed that with the increase in time of exposure to radiation, the mean tail length also increased.

Occurrence of Chromosomal Aberrations in Human Populations of Two Endogamous Groups of Haryana

Abstract Cytogenetic assays in peripheral blood lymphocytes (PBL) have been done to assess the incidences of chromosomal aberrations among Meos and Sunni Muslims of Haryana. Baseline frequencies of chromosome aberrations (CA) were assessed in 28 subjects from each cast. The mean frequency of chromosomal gaps in Meos was found to be 0.786 ± 0.686 and the frequency of chromosomal break was 0.429 ± 0.504. Mean frequency of the satellite association in Meos was found to be 1.357 ± 1.821. Among the Sunni Muslims the mean frequency of chromosomal gaps was found to be 1.250 ±0.701 and the frequency of chromosomal breaks was 0.643 ± 0.488. Mean frequency of satellite in Sunni Muslims was found to be 1.250 ± 1.435. Statistically non-significant differences were observed for the gaps, break and satellite associations, whereas values for total aberrations were found to be statistically significant among Meos and Sunni Muslims. The mean values for chromosomal aberrations and satellite associations were higher in Sunni Muslims (1.893) than in Meos (1.214).

DNA damage in the peripheral blood lymphocytes of asthmatic patients in relation to disease progression

With increased incidences in recent times especially in the urban population, asthma represents a major global concern. The inflammatory reaction of the airways in asthmatic patients leads to generation of reactive oxygen intermediates which interfere with the basic structure of DNA causing genomic instability. The present study was aimed to assess the DNA damage in the peripheral blood lymphocytes in asthmatic subjects. Blood samples from 95 asthmatic subjects and 57 controls were analysed for DNA damage using Comet assay. Statistical analysis was done using student’s t test and ANOVA. p < 0.05 was considered significant. Significant elevation was observed in % tail DNA (p < 0.05) in asthmatic subjects as compared to their non-asthmatic counterparts. Tail length, tail and olive moment were also markedly higher in asthmatics subjects (p < 0.05). The DNA damage was evidently higher in patients with severe asthma as compared to those with mild and moderate asthma (p < 0.05). The genomic instability was positively correlated with the age of subjects and severity of asthma which implied association of DNA damage with asthma and its progression with duration and severity.

Karyomorphological studies from mitotic metaphases in three carp species

Karyological analysis of three carp species viz. Ctenopharyngodon idella, Hypophthalmichthyes molitrix, and Cyprinus carpio communis belonging to family Cyprinidae was carried out. The study samples of these species were collected from local fish farm in Haryana. The diploid chromosome number in C. idella was found to be 2n = 48, with 13 pairs of metacentric, 3 pairs of submetacentric and 8 pairs of acrocentric chromosomes. Chromosomal studies on the H. molitrix revealed the diploid chromosome number to be 2n = 48, with 6 pairs of metacentric, 6 pairs of submetacentric and 12 pairs of acrocentric chromosomes. The diploid chromosome number in C. c. communis was found to be 2n = 100, with 17 pairs of metacentric, 3 pairs of submetacentric, 1 pair of subtelocentric and 29 pairs of acrocentric chromosomes. Arm ratio, centromeric index and fundamental number of arms was also determined. The study reveals that diversification in these carp species of cyprinidae family is related to structural changes in chromosomes. Habitat conditions and anthropogenic activities might be responsible for incidence of pericentric inversions causing karyomorphological changes and thereby variation in karytype formulae vis-à-vis earlier reports.