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Search Results: 1 - 10 of 201086 matches for " Sabapathy P. Balasubramanian "
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Endostatin gene variation and protein levels in breast cancer susceptibility and severity
Sabapathy P Balasubramanian, Simon S Cross, Jenny Globe, Angela Cox, Nicola J Brown, Malcolm W Reed
BMC Cancer , 2007, DOI: 10.1186/1471-2407-7-107
Abstract: The 4349G > A (coding non-synonymous) polymorphism in exon 42 of the Endostatin gene was genotyped in approximately 846 breast cancer cases and 707 appropriate controls. In a separate healthy cohort of 57 individuals, in addition to genotyping, serum Endostatin levels were measured using enzyme linked immunosorbant assay (ELISA). A semi-quantitative assessment of Endostatin protein expression on immunostained tissue micro arrays (TMA) constructed from breast cancer samples of patients with genotype data was performed.The rare allele (A) was significantly associated with invasive breast cancers compared to non-invasive tumours (p = 0.03), but there was no association with tumour grade, nodal status, vascular invasion or overall survival. There was no association with breast cancer susceptibility. Serum Endostatin levels and Endostatin protein expression on the tissue micro array were not associated with genotype.The Endostatin 4349A allele is associated with invasive breast cancer. The Endostatin 4349G > A polymorphism however does not appear to be associated with breast cancer susceptibility or severity in invasive disease. By studying circulating levels and tumour Endostatin protein expression, we have shown that any influence of this polymorphism is unlikely to be through an effect on the levels of protein produced.Endostatin, a fragment of collagen 18-1α, was first identified in the conditioned medium of a hemangioendothelioma cell line as a potent inhibitor of angiogenesis and tumour growth [1]. The parent molecule releases Endostatin after proteolytic digestion by elastase and cathepsin L [2]. Endostatin inhibits endothelial cell proliferation and migration and induces apoptosis [3-5]. Several mechanisms have been postulated to explain the anti-angiogenic effects of Endostatin. One such mechanism is the high affinity of Endostatin for heparin explained by the presence of an extensive basic patch formed by 11 arginine residues. The interaction with heparin can i
Associations of ATR and CHEK1 Single Nucleotide Polymorphisms with Breast Cancer
Wei-Yu Lin, Ian W. Brock, Dan Connley, Helen Cramp, Rachel Tucker, Jon Slate, Malcolm W. R. Reed, Sabapathy P. Balasubramanian, Lisa A. Cannon-Albright, Nicola J. Camp, Angela Cox
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0068578
Abstract: DNA damage and replication checkpoints mediated by the ATR-CHEK1 pathway are key to the maintenance of genome stability, and both ATR and CHEK1 have been proposed as potential breast cancer susceptibility genes. Many novel variants recently identified by the large resequencing projects have not yet been thoroughly tested in genome-wide association studies for breast cancer susceptibility. We therefore used a tagging SNP (tagSNP) approach based on recent SNP data available from the 1000 genomes projects, to investigate the roles of ATR and CHEK1 in breast cancer risk and survival. ATR and CHEK1 tagSNPs were genotyped in the Sheffield Breast Cancer Study (SBCS; 1011 cases and 1024 controls) using Illumina GoldenGate assays. Untyped SNPs were imputed using IMPUTE2, and associations between genotype and breast cancer risk and survival were evaluated using logistic and Cox proportional hazard regression models respectively on a per allele basis. Significant associations were further examined in a meta-analysis of published data or confirmed in the Utah Breast Cancer Study (UBCS). The most significant associations for breast cancer risk in SBCS came from rs6805118 in ATR (p=7.6x10-5) and rs2155388 in CHEK1 (p=3.1x10-6), but neither remained significant after meta-analysis with other studies. However, meta-analysis of published data revealed a weak association between the ATR SNP rs1802904 (minor allele frequency is 12%) and breast cancer risk, with a summary odds ratio (confidence interval) of 0.90 (0.83-0.98) [p=0.0185] for the minor allele. Further replication of this SNP in larger studies is warranted since it is located in the target region of 2 microRNAs. No evidence of any survival effects of ATR or CHEK1 SNPs were identified. We conclude that common alleles of ATR and CHEK1 are not implicated in breast cancer risk or survival, but we cannot exclude effects of rare alleles and of common alleles with very small effect sizes.
Human Wharton’s Jelly Mesenchymal Stem Cells Plasticity Augments Scar-Free Skin Wound Healing with Hair Growth
Vikram Sabapathy, Balasubramanian Sundaram, Sreelakshmi VM, Pratheesh Mankuzhy, Sanjay Kumar
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0093726
Abstract: Human mesenchymal stem cells (MSCs) are a promising candidate for cell-based transplantation and regenerative medicine therapies. Thus in the present study Wharton’s Jelly Mesenchymal Stem Cells (WJ-MSCs) have been derived from extra embryonic umbilical cord matrix following removal of both arteries and vein. Also, to overcome the clinical limitations posed by fetal bovine serum (FBS) supplementation because of xenogeneic origin of FBS, usual FBS cell culture supplement has been replaced with human platelet lysate (HPL). Apart from general characteristic features of bone marrow-derived MSCs, wharton jelly-derived MSCs have the ability to maintain phenotypic attributes, cell growth kinetics, cell cycle pattern, in vitro multilineage differentiation plasticity, apoptotic pattern, normal karyotype-like intrinsic mesenchymal stem cell properties in long-term in vitro cultures. Moreover, the WJ-MSCs exhibited the in vitro multilineage differentiation capacity by giving rise to differentiated cells of not only mesodermal lineage but also to the cells of ectodermal and endodermal lineage. Also, WJ-MSC did not present any aberrant cell state upon in vivo transplantation in SCID mice and in vitro soft agar assays. The immunomodulatory potential assessed by gene expression levels of immunomodulatory factors upon exposure to inflammatory cytokines in the fetal WJ-MSCs was relatively higher compared to adult bone marrow-derived MSCs. WJ-MSCs seeded on decellularized amniotic membrane scaffold transplantation on the skin injury of SCID mice model demonstrates that combination of WJ-MSCs and decellularized amniotic membrane scaffold exhibited significantly better wound-healing capabilities, having reduced scar formation with hair growth and improved biomechanical properties of regenerated skin compared to WJ-MSCs alone. Further, our experimental data indicate that indocyanin green (ICG) at optimal concentration can be resourcefully used for labeling of stem cells and in vivo tracking by near infrared fluorescence non-invasive live cell imaging of labelled transplanted cells, thus proving its utility for therapeutic applications.
Lactate Dehydrogenase-B Is Silenced by Promoter Methylation in a High Frequency of Human Breast Cancers
Nicola J. Brown, Sue E. Higham, Branko Perunovic, Mohammad Arafa, Sabapathy Balasubramanian, Ishtiaq Rehman
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0057697
Abstract: Objective Under normoxia, non-malignant cells rely on oxidative phosphorylation for their ATP production, whereas cancer cells rely on Glycolysis; a phenomenon known as the Warburg effect. We aimed to elucidate the mechanisms contributing to the Warburg effect in human breast cancer. Experimental design Lactate Dehydrogenase (LDH) isoenzymes were profiled using zymography. LDH-B subunit expression was assessed by reverse transcription PCR in cells, and by Immunohistochemistry in breast tissues. LDH-B promoter methylation was assessed by sequencing bisulfite modified DNA. Results Absent or decreased expression of LDH isoenzymes 1-4, were seen in T-47D and MCF7 cells. Absence of LDH-B mRNA was seen in T-47D cells, and its expression was restored following treatment with the demethylating agent 5'Azacytadine. LDH-B promoter methylation was identified in T-47D and MCF7 cells, and in 25/ 25 cases of breast cancer tissues, but not in 5/ 5 cases of normal breast tissues. Absent immuno-expression of LDH-B protein (<10% cells stained), was seen in 23/ 26 (88%) breast cancer cases, and in 4/8 cases of adjacent ductal carcinoma in situ lesions. Exposure of breast cancer cells to hypoxia (1% O2), for 48 hours resulted in significant increases in lactate levels in both MCF7 (14.0 fold, p = 0.002), and T-47D cells (2.9 fold, p = 0.009), but not in MDA-MB-436 (-0.9 fold, p = 0.229), or MCF10AT (1.2 fold, p = 0.09) cells. Conclusions Loss of LDH-B expression is an early and frequent event in human breast cancer occurring due to promoter methylation, and is likely to contribute to an enhanced glycolysis of cancer cells under hypoxia.
Studies on the growth aspects of organic L-alanine maleate: a promising nonlinear optical crystal  [PDF]
D. Balasubramanian, R. Jayavel, P. Murugakoothan
Natural Science (NS) , 2009, DOI: 10.4236/ns.2009.13029
Abstract: A organic nonlinear optical material, L-alanine maleate (LALM) was synthesized. Bulk Single crystals of LALM have been grown by slow cooling method with a solution pH of 5. The solubility of L-alanine maleate has been deter-mined for various temperatures. Large size sin-gle crystal of 2.0 x 1.2 x 0.8 cm3 has been grown with reasonable growth rate along the three crystallographic directions by optimizing the growth parameters. The structure of LALM crys- tal was studied by single-crystal X-ray diffrac-tion analysis. The presence of functional groups was confirmed by Fourier transform infrared spectroscopy. The LALM crystal was analysed for its thermal and mechanical behaviours. The grown crystals have also been subjected to linear and non-linear optical property studies. From these studies, it is inferred that the LALM crystals exhibit better thermal and mechanical stabilities with improved optical properties. Thus satisfies the essential requirements for optical device fabrication.
Preparation and Properties of Polyester-Based Nanocomposite Gel Coat System
P. Jawahar,M. Balasubramanian
Journal of Nanomaterials , 2006, DOI: 10.1155/jnm/2006/21656
Abstract: Nanocomposite gel coat system is prepared using unsaturated polyester resin with aerosil powder, CaCO3, and organoclay. The influence of organoclay addition on mechanical and water barrier properties of gel coat system is studied for different amount (1, 2, and 3 wt %) of organoclay. The nanolevel incorporation of organoclay improves the mechanical and water barrier properties of nanocomposite gel coat system. The nanocomposite gel coat system exhibits 55% improvement in tensile modulus and 25% improvement in flexural modulus. There is a 30% improvement in impact property of nanocomposite gel coat system. The dynamic mechanical analysis shows a slight increase in glass transition temperature for nanocomposite gel coat system.
Removal of Cr(VI) from aqueous solution using Bacillus subtilis, Pseudomonas aeruginosa and Enterobacter cloacae
P. Sethuraman,,N. Balasubramanian
International Journal of Engineering Science and Technology , 2010,
Abstract: The objective of this study is to investigate the removal efficiency of Cr(VI) by Bacillus subtilis, Pseudomonas aeruginosa and Enterobacter cloacae from aqueous solution under different process conditions. Batch mode experiments were carried out as a function of solution pH, biosorbent dosage, Cr(VI) concentration and contact time.The FT-IR spectra and SEM analysis of the biosorbent were recorded to analyse the number and position of the functional groups available for the binding of Cr(VI) ions and to study the morphology of biosorbent. The batch isothermal equilibrium data were analyzed with Freundlich and Langmuir isotherm models. The kinetic models were examined with pseudo first order and pseudo second order kinetics. The results revealed that the Cr(VI) is considerably adsorbed on bacterial biomass and it could be an economical method for the removal of Cr(VI) from aqueous solution.
Hybrid Carbon-Carbon Ablative Composites for Thermal Protection in Aerospace
P. Sanoj,Balasubramanian Kandasubramanian
Journal of Composites , 2014, DOI: 10.1155/2014/825607
Abstract: Composite materials have been steadily substituting metals and alloys due to their better thermomechanical properties. The successful application of composite materials for high temperature zones in aerospace applications has resulted in extensive exploration of cost effective ablative materials. High temperature heat shielding to body, be it external or internal, has become essential in the space vehicles. The heat shielding primarily protects the substrate material from external kinetic heating and the internal insulation protects the subsystems and helps to keep coefficient of thermal expansion low. The external temperature due to kinetic heating may increase to about maximum of 500°C for hypersonic reentry space vehicles while the combustion chamber temperatures in case of rocket and missile engines range between 2000°C and 3000°C. Composite materials of which carbon-carbon composites or the carbon allotropes are the most preferred material for heat shielding applications due to their exceptional chemical and thermal resistance. 1. Introduction Discovery of carbon-carbon composites in 1958 by Brennan Chance Vought Aircraft created an opportunity to these principle materials for heat shielding appliances due to their high strength and thermal resistance [1]. Rayon carbon fabric reinforced phenolic (C–Ph) composites are the broadly used thermal protection systems due to the low thermal conductivity of the rayon fabric and high char yields of the phenolic resin. In general, carbon phenolic composites show better ablation resistance and continued enhancement of ablative property with the development of a thinner ablative composite structure for better pay load and fuel efficiency [2]. The Space Shuttle Columbia disaster occurred on February 1, 2003, due to the inadequate impact resistance of the thermal insulation foam in the external tank against air, as the spacecraft reentered the earth’s planetary atmospheric domain. The displaced reinforcement foam damaged Columbia’s left reinforced carbon-carbon (RCC) panels thereby causing the unfortunate accident. This incident paves way for a detailed research to enhance impact tolerances, thermal resistance, and fracture toughness of the RCC panels [3]. Polymer nanocomposites are the three phase composite systems invented by Toyota research group, wherein nanosize particles, dispersed in the two phase fiber reinforced composites, exhibit enhanced structural rigidity and ablation resistance [1]. Nanocomposites have the capability to withstand the simultaneous action of thermal stresses and mechanical impact
Impact of biomass burning on ocean water quality in Southeast Asia through atmospheric deposition: eutrophication modeling
P. Sundarambal, P. Tkalich,R. Balasubramanian
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2010,
Abstract: Atmospheric deposition of nutrients (N and P species) can intensify anthropogenic eutrophication of coastal waters. It was found that the atmospheric wet and dry depositions of nutrients was remarkable in the Southeast Asian region during the course of smoke haze events, as discussed in a companion paper on field observations (Sundarambal et al., 2010b). The importance of atmospheric deposition of nutrients in terms of their biological responses in the coastal waters of the Singapore region was investigated during hazy days in relation to non-hazy days. The influence of atmospherically-derived, bio-available nutrients (both inorganic and organic nitrogen and phosphorus species) on the coastal water quality between hazy and non-hazy days was studied. A numerical modeling approach was employed to provide qualitative and quantitative understanding of the relative importance of atmospheric and ocean nutrient fluxes in this region. A 3-D eutrophication model, NEUTRO, was used with enhanced features to simulate the spatial distribution and temporal variations of nutrients, plankton and dissolved oxygen due to atmospheric nutrient loadings. The percentage increase of the concentration of coastal water nutrients relative to the baseline due to atmospheric deposition was estimated between hazy and non-hazy days. Model computations showed that atmospheric deposition fluxes of nutrients might account for up to 17 to 88% and 4 to 24% of total mass of nitrite + nitrate-nitrogen in the water column, during hazy days and non-hazy days, respectively. The results obtained from the modeling study could be used for a better understanding of the energy flow in the coastal zone system, exploring various possible scenarios concerning the atmospheric deposition of nutrients onto the coastal zone and studying their impacts on water quality.
An Innovative Approach of RPC for Secure Transmission of Encrypted Gray Scale Images
Shenbagarajan Anantharajan,P. Subbalakshmi,C. Balasubramanian
International Journal of Soft Computing , 2012, DOI: 10.3923/ijscomp.2012.164.168
Abstract: Secure transmission over an insecure channel can be achieved through the compression of data for efficiency followed by encrypting it for security. By reversing the operations, it is possible to improve secrecy. The lossless compression of encrypted sources can be achieved through Slepian-Wolf coding. The use of markov properties in the Slepian-Wolf decoder do not work well for grayscale images. This drawback can be rectified by Resolution Progressive Compression (RPC) scheme which compresses the encrypted image progressively in resolution such that the decoder can observe a low resolution version of image, study the local statistics based on it and use statistics to decode the next resolution level.
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