METHODS: Polymerase chain reaction primers were designed and validated to specifically amplify the cytosine that is followed by guanine residues (CpGs) A and B regions. Prior epigenotyping on 110 Kelantanese Malays, the serial pyrosequencing assays for the CpGs A and B regions were validated using five validation controls. The mean values of the DNA methylation profiles of CpGs A and B were calculated.
RESULTS: The mean DNA methylation levels for CpGs A and B were 0.984 ± 0.582 and 2.456 ± 1.406, respectively. The CpGs 8 and 20 showed the highest (5.581 ± 4.497) and the lowest (0.414 ± 2.814) levels of DNA methylation at a single-base resolution.
CONCLUSION: We have successfully developed and validated a pyrosequencing assay that is fast and can yield high-quality pyrograms for DNA methylation analysis and is therefore applicable to high throughput study. Using this newly developed pyrosequencing assay, the MTHFR DNA methylation profiles of 110 Kelantanese Malays were successfully determined. It also validated our computational epigenetic research on MTHFR.
METHODS: Graphite furnace atomic absorption spectrometry (GF-AAS) was used to evaluate six digestion methods, (1) nitric acid, (2) nitric acid overnight, (3) nitric acid-hydrogen peroxide, (4) nitric-perchloric acid, (5) sulfuric acid, and (6) dry ashing, to determine the most suitable digestion method for the determination of heavy metals in the samples.
RESULTS: The concentration ranges of Cd, Pb, As and Se in fresh tea leaves were from 0.03-0.13, 0.19-2.06 and 0.47-1.31 µg/g, respectively while processed tea contained heavy metals at different concentrations: Cd (0.04-0.16 µg/g), Cr (0.45-10.73 µg/g), Pb (0.07-1.03 µg/g), As (0.89-1.90 µg/g) and Se (0.21-10.79 µg/g). Moreover, the soil samples of tea plantations also showed a wide range of concentrations: Cd (0.11-0.45 µg/g), Pb (2.80-66.54 µg/g), As (0.78-4.49 µg/g), and Se content (0.03-0.99 µg/g). Method no. 2 provided sufficient time to digest the tea matrix and was the most efficient method for recovering Cd, Cr, Pb, As and Se. Methods 1 and 3 were also acceptable and can be relatively inexpensive, easy and fast. The heavy metal transfer factors in the investigated soil/tea samples decreased as follows: Cd > As > Se > Pb.
CONCLUSION: Overall, the present study gives current insights into the heavy metal levels both in soils and teas commonly consumed in Bangladesh.
METHODS: Genotyping of CYP3A4*18 and CYP3A5*3 was performed using the polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) technique. The association between allelic variants and treatment response was assessed by means of odds ratio (OR) with 95% confidence intervals calculated by logistic regression.
RESULTS: Our results indicated that CML patients carrying the heterozygous (AG) and homozygous variant (GG) genotype of CYP3A5*3 were associated with a significantly lower risk of acquiring resistance with OR 0.171; 95% CI: 0.090-0.324, p