Uranium standards in drinking water: An examination from scientific and socio-economic standpoints of India.

The detection of uranium in drinking water has ignited concerns among the public, regulators, and policymakers, particularly as around 1% of the 55,554 water samples in India have shown uranium levels surpassing the 60 µg/l guideline established by the Atomic Energy Regulatory Board (AERB) based on radiological toxicity. Further, the Bureau of Indian Standard (BIS), has given a limit of 30 µg/l, which is derived from World Health Organization (WHO) guidelines. Besides the chemical and radiological aspects associated with uranium, factors such as technological constraints in water purification, waste management, environmental factors, and socio-economic conditions significantly influence these guideline values, which are often overlooked. This manuscript explores the variations in approaches for establishing guideline values and highlights the uncertainties arising from dependence on various variables such as intake and usage patterns, inter- and intra-species distinctions, and epidemiological data. A critical analysis indicates that adherence to global guidelines may result in some undesirable environmental issues. By considering factors such as population dynamics, socio-economic conditions, and geological influences, we suggest that limit of 60 µg/l for uranium in drinking water is appropriate for India.

Generation of map on natural environmental background absorbed dose rate in India.

A systematic mapping of natural absorbed dose rate was carried out to assess the existing exposure situation in India. The mammoth nationwide survey covered the entire terrestrial region of the country comprising of 45127 sampling grids (grid size 36 km2) with more than 100,000 data points. The data was processed using Geographic Information System. This study is based on established national and international approaches to provide linkage with conventional geochemical mapping of soil. Majority (93%) of the absorbed dose rate data was collected using handheld radiation survey meters and remaining were measured using environmental Thermo Luminescent Dosimeters. The mean absorbed dose rate of the entire country including several mineralized regions, was found to be 96 ± 21 nGy/h. The median, Geometric Mean and Geometric Standard Deviation values of absorbed dose rate were 94, 94 and 1.2 nGy/h, respectively. Among the High Background Radiation Areas of the country, absorbed dose rate varied from 700 to 9562 nGy/h in Karunagappally area of Kollam district, Kerala. The absorbed dose rate in the present nationwide study is comparable with the global database.

Investigations on baseline levels for natural radioactivity in soils, rocks, and lakes of Larsemann Hills in East Antarctica.

A comprehensive measurement of concentrations of the natural radionuclides 238U, 232Th and 40K, and 226Ra in the soil and rocks along with natural uranium and tritium activity levels in lake water were carried out during the Indian expedition to Antarctica. The samples were collected from the Larsemann Hills region in Antarctica (latitude 69°20' S to 69°25'S, longitude 76°6' E to 76°23'E). The data on the natural radioactivity for this region is limited. The study was carried out to establish baseline levels of radioactivity in different terrestrial matrices of this region such as soil, rocks, and lake water. A radiation survey mapping for terrestrial radioactivity was conducted in the region before collection of soil and rock samples. The soil and rock samples were analyzed for natural radioactivity concentrations using high-resolution gamma spectroscopy system. The major contributor to elevated gamma radiation background is attributed to the higher concentration of 232Th and 40K radionuclides in both soil and rocks. Terrestrial components of gamma dose rate due to natural radioactivity have been estimated from the measured radioactivity concentrations and dose conversion coefficients. Several "hotspots" and high background areas in the region have been identified having significantly higher concentration of 232Th and 40K. Rocks in Larsemann Hills region showed high reserve of thorium mineralization in monazites and 40K in K-feldspar. The concentrations of 232Th in soil are found to be in the range of 106-603 Bq/kg, whereas in rock it is in the range of 8-4514 Bq/kg. Natural radioactivity U (nat) and 3H contents in the lake water samples in Larsemann Hills region were estimated as 0.4 and 1.3 Bq/L and are well within the prescribed limit of radioactivity in drinking water as recommended by World Health Organization.

Epigenetic choreography of stem cells: the DNA demethylation episode of development.

Reversible DNA methylation is a fundamental epigenetic manipulator of the genomic information in eukaryotes. DNA demethylation plays a very significant role during embryonic development and stands out for its contribution in molecular reconfiguration during cellular differentiation for determining stem cell fate. DNA demethylation arbitrated extensive make-over of the genome via reprogramming in the early embryo results in stem cell plasticity followed by commitment to the principal cell lineages. This article attempts to highlight the sequential phases and hierarchical mode of DNA demethylation events during enactment of the molecular strategy for developmental transition. A comprehensive knowledge regarding the pattern of DNA demethylation during embryogenesis and organogenesis and study of the related lacunae will offer exciting avenues for future biomedical research and stem cell-based regenerative therapy.

Endocrine markers for identifying prolificacy potential and predicting fetal number in goats.

Identifying prolificacy potential and determination of fetal number during pregnancy for proper care and management of the pregnant goats bearing multiple fetuses and achieving the benefits out of multiple births are essential for sustainable goat farming. Our objectives were (1) to examine prolificacy potential in goats by using pituitary response to gonadotrophin releasing hormone (GnRH) challenge test, (2) to investigate hormonal profiles for the prediction of fetal number in pregnant goats and (3) to find out the most reliable timing of blood sampling for discriminating prolificacy trait and differentiating the goats bearing single, twin and triplet fetuses. In first experiment (GnRH challenge test), plasma FSH concentrations were significantly higher (P<0.01) among the goats belonging to triplet vs. twin vs. single kidding size groups after GnRH administration. Multivariate stepwise discriminant function analysis recognized that one blood sampling at 220min after GnRH administration can be used to distinguish prolificacy potential in goats. In second experiment, plasma progesterone levels were significantly higher (P<0.01) in goats bearing triplet vs. twin vs. single fetus between day 84 and 21 prior to parturition. Plasma estrone sulphate concentrations were found to be higher (P<0.05) in does bearing multiple fetuses than the does bearing single fetus between day 126 and 28 prior to parturition. A single blood sampling at day 63 prior to parturition was the most probable suitable time for discriminating kidding size by using plasma progesterone as marker.

Molecular marks for epigenetic identification of developmental and cancer stem cells.

UNLABELLED: Epigenetic regulations of genes by reversible methylation of DNA (at the carbon-5 of cytosine) and numerous reversible modifications of histones play important roles in normal physiology and development, and epigenetic deregulations are associated with developmental disorders and various disease states, including cancer. Stem cells have the capacity to self-renew indefinitely. Similar to stem cells, some malignant cells have the capacity to divide indefinitely and are referred to as cancer stem cells. In recent times, direct correlation between epigenetic modifications and reprogramming of stem cell and cancer stem cell is emerging. Major discoveries were made with investigations on reprogramming gene products, also known as master regulators of totipotency and inducer of pluoripotency, namely, OCT4, NANOG, cMYC, SOX2, Klf4, and LIN28. The challenge to induce pluripotency is the insertion of four reprogramming genes (Oct4, Sox2, Klf4, and c-Myc) into the genome. There are always risks of silencing of these genes by epigenetic modifications in the host cells, particularly, when introduced through retroviral techniques. In this contribution, we will discuss some of the major discoveries on epigenetic modifications within the chromatin of various genes associated with cancer progression and cancer stem cells in comparison to normal development of stem cell. These modifications may be considered as molecular signatures for predicting disorders of development and for identifying disease states. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s13148-010-0016-0) contains supplementary material, which is available to authorized users.

5-Aza-2'-deoxycytidine stress response and apoptosis in prostate cancer.

While studying on epigenetic regulatory mechanisms (DNA methylation at C-5 of -CpG- cytosine and demethylation of methylated DNA) of certain genes (FAS, CLU, E-cadh, CD44, and Cav-1) associated with prostate cancer development and its better management, we noticed that the used in vivo dose of 5-aza-2'-deoxycytidine (5.0 to 10.0 nM, sufficient to inhibit DNA methyltransferase activity in vitro) helped in the transcription of various genes with known (steroid receptors, AR and ER; ER variants, CD44, CDH1, BRCA1, TGFßR1, MMP3, MMP9, and UPA) and unknown (DAZ and Y-chromosome specific) proteins and the respective cells remained healthy in culture. At a moderate dose (20 to 200 nM) of the inhibitor, cells remain growth arrested. Upon subsequent challenge with increased dose (0.5 to 5.0 µM) of the inhibitor, we observed that the cellular morphology was changing and led to death of the cells with progress of time. Analyses of DNA and anti-, pro-, and apoptotic factors of the affected cells revealed that the molecular events that went on are characteristics of programmed cell death (apoptosis).

Demethylation of (Cytosine-5-C-methyl) DNA and regulation of transcription in the epigenetic pathways of cancer development.

Cancer cells and tissues exhibit genome wide hypomethylation and regional hypermethylation. CpG-methylation of DNA ((Me)CpG-DNA) is defined as the formation of a C-C covalent bond between the 5'-C of cytosine and the -CH(3) group of S-adenosylmethionine. Removal of the sole -CH(3) group from the methylated cytosine of DNA is one of the many ways of DNA-demethylation, which contributes to activation of transcription. The mechanism of demethylation, the candidate enzyme(s) exhibiting direct demethylase activity and associated cofactors are not firmly established. Genome-wide hypomethylation can be obtained in several ways by inactivation of DNMT enzyme activity, including covalent trapping of DNMT by cytosine base analogues. Removal of methyl layer could also be occurred by excision of the 5-methyl cytosine base by DNA glycosylases. The importance of truly chemically defined direct demethylation of intact DNA in regulation of gene expression, development, cell differentiation and transformation are discussed in this contribution.

Methyl-CpG-DNA binding proteins in human prostate cancer: expression of CXXC sequence containing MBD1 and repression of MBD2 and MeCP2.

We analyzed gene expression of MBD1, MBD2, MBD3, MBD4, and MeCP2 and protein expression of MBD1, MBD2, and MeCP2 in prostate cancer cell lines, benign prostate epithelium (BPH-1) cell line, 49 BPH tissues, and 46 prostate cancer tissues. The results of this study demonstrate that MBD2 gene is expressed in all samples and MeCP2 gene is expressed in all cancer cell lines but not in BPH-1 cell line. However, there was no protein expression for MBD2 and MeCP2 in cancer cell lines and cancer tissues. For CXXC sequence containing MBD1, both protein and mRNA were expressed in cancer cell lines, cancer tissues, BPH-1 cell line, and BPH tissues. We observed that, in BPH tissues and low-grade cancer tissues, MBD1 protein expression was very high and gradually decreased with increase of cancer grade. Treatment of cancer cell lines with proteasome inhibitor (MG-132) did not restore expression of MBD2 and MeCP2 proteins. When prostate cancer cell lines were treated with hypomethylating agent, 5-aza-2(')-deoxycytidine (DNMT inhibitor), HDAC1 and HDAC2 expression was decreased. This is the first report demonstrating that CXXC sequence containing MBD1 is overexpressed and can be the major factor of hypermethylated chromatin segments through HDAC1/2 translocation and histone deacetylation in human prostate cancer.

Transforming growth factor-beta(s) and their receptors in aging rat prostate.

We hypothesize that rat fetal urogenital sinus mesenchyme (UGM) can induce prostatic growth of growth quiescent adult rat prostate through modulations of TGFbetas and their receptors. To test this hypothesis, prostatic ducts from aging rat prostate (4, 12, 17, 22, and 27 months) were combined with fetal rat UGM and grafted under renal capsule of athymic nude mice. At 1, 3, and 5 months the tissue recombinants were harvested from renal capsule and analyzed for their growth. The gene and protein expression of TGFbeta1, 2, 3 and their receptors, TbetaR-I and TbetaR-II, were analyzed by RT-PCR and immunohistochemistry, respectively. The results of these experiments demonstrate that prostate ducts when combined with rat UGM formed larger grafts as compared to control (prostatic ducts without UGM). The older rat prostate recombinants (17, 22, and 27 months) formed larger grafts (159 mg/graft) as compared to younger rat prostate (4 and 12 months) grafts (51 mg/graft). The mRNA and protein expression for TbetaR-I and TbetaR-II in 22 and 27 months rat prostate tissue recombinants were significantly lower than 4, 12, and 17 month tissue recombinants. However, mRNA expression for TGFbeta1, TGFbeta2, and TGFbeta3 did not change with aging rat tissue recombinants. The protein expression for TGFbeta1 was significantly up-regulated whereas TGFbeta2 and TGFbeta3 were down-regulated with aging prostate tissue recombinants. The present study demonstrates for the first time that rat fetal UGM differentially induces growth of aging rat prostate in a tissue recombinant model. The mechanisms of induction may be through up-regulation of TGFbeta1 and down-regulation of TGFbeta2, and TGFbeta3. However, the action of TGFbetas may be through TbetaR-I and TbetaR-II independent pathways since these receptors were lacking or low in older rat prostate tissue recombinants. These findings are important in understanding the mechanisms of UGM mediated prostatic growth.

DNA methyltransferase and demethylase in human prostate cancer.

Recent studies have shown that cytosine-5 methylation at CpG islands in the regulatory sequence of a gene is one of the key mechanisms of inactivation. The enzymes responsible for CpG methylation are DNA methyltransferase (DNMT) 1, DNMT3a, and DNMT3b, and the enzyme responsible for demethylation is DNA demethylase (MBD2). Studies on methylation-demethylation enzymes are lacking in human prostate cancer. We hypothesize that MBD2 enzyme activity is repressed and that DNMT1 enzyme activity is elevated in human prostate cancer. To test this hypothesis, we analyzed enzyme activities, mRNA, and protein levels of MBD2 and DNMT1, DNMT3a, and DNMT3b in human prostate cancer cell lines and tissues. The enzyme activities of DNMTs and MBD2 were analyzed by biochemical assay. The mRNA expression was analyzed by reverse transcriptase-polymerase chain reaction and by Northern blotting. The protein expression was measured by immunohistochemistry with specific antibodies. The results of these experiments demonstrated that (1) the activity of DNMTs was twofold to threefold higher in cancer cell lines and cancer tissues, as compared with a benign prostate epithelium cell line (BPH-1) and benign prostatic hyperplasia (BPH) tissues; (2) MBD2 activity was lacking in prostate cancer cell lines but present in BPH-1 cells; (3) immunohistochemical analyses exhibited higher expression of DNMT1 in all prostate cancer cell lines and cancer tissues, as compared with BPH-1 cell lines and BPH tissues; (4) MBD2 protein expression was significantly higher in BPH-1 cells and lacking in prostate cancer cell lines and, in BPH tissues, MBD2 protein expression was poorly observed, as compared with no expression in prostate cancer tissues; and (5) mRNA expression for DNMT1 was upregulated in prostate cancer, as compared with BPH-1, and mRNA expression for MBD2 was found to be significantly expressed in all cases. The results of these studies clearly demonstrate that DNMT1 activity is upregulated, whereas MBD2 is repressed at the level of translation in human prostate cancer. These results may demonstrate molecular mechanisms of CpG hypermethylation of various genes in prostate cancer.

Effects of aging on growth factors gene and protein expression in the dorsal and ventral lobes of rat prostate.

We hypothesize that various growth factors and their receptors gene and protein are modulated in dorsal and ventral lobes of aging prostate. To test this hypothesis, TGFbeta1, TGFbeta2 TGFbeta3, TGFbetaR-I, TGFbetaR-II, TGFalpha, EGF, EGFR, KGF and KGFR gene and protein expression were analyzed in dorsal and ventral lobes of aging rat prostates (1, 3, 6, 9, 12, 18, 24, and 28/30 months). KGF gene expression was very weak or absent in 1, 3, and 6 month old rat dorsal and ventral lobes of prostate whereas it re-expressed in 9, 12, 18, 24 and 30 month old rat prostate. All growth factors and their receptors expect KGF and EGFR were mainly localized in epithelium of ventral and dorsal lobes of aging rat prostates. EGF, TGFalpha, TGFbeta1, and TGFbetaR-I protein expression was lacking in stroma of dorsal and ventral lobes of 1, 3, 6, 9, 12/18 months old rat prostates. However, EGF, TGFbeta1 and TGFbetaR-I proteins re-expressed in stroma of 24 and 28 months old rat prostates. KGF protein expression was lacking in epithelium of dorsal and ventral lobes of all aging rat prostates. This is the first report to demonstrate differential gene and protein expression of growth factors in dorsal and ventral lobes is associated with aging rat prostate, suggesting their role in pathogenesis of prostatic diseases with aging.