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Peptides designed from osteoprotegerin (OPG) have previously been shown to inhibit receptor activator of NF-κB ligand (RANKL) and prevent bone loss without significantly inhibiting inflammation. The objective of this study was to develop a novel peptide with dual inhibitory activity against bone loss and inflammation using site-directed mutagenesis. Out of the three putative sites (i.e., Tyr70-Asp78, Tyr82-Glu96, and Leu113-Arg122) available on OPG for RANKL binding, Leu113-Arg122 was used as a template for peptide synthesis. Peptide mutants of the template sequence (112YLEIEFCLKHR122) were synthesized and initially screened for their inhibitory effect on RANK-RANKL binding by competitive ELISA. The most active peptide was further evaluated in vitro for RANKL induced osteoclastogenesis in mouse macrophage cells, and in vivo for Freund's complete adjuvant induced arthritis (AIA) in Lewis rats. The efficacy of the candidate peptide was compared with that of the standard drug celecoxib. The peptide YR-11 (YLEIEFSLKHR), obtained by direct substitution of cysteine with a serine residue in the template sequence, significantly (p0.05) inhibited RANK-RANKL binding, and RANKL induced TRAP activity and formation of multinucleated osteoclasts without any cytotoxicity. Administration of YR-11 peptide at the dose of 30mg/kg (i.p.) ameliorated both bone loss and inflammation in AIA rats. To elucidate the mechanism for inhibition of inflammation in arthritic rats, serum and tissue cytokines (TNF-α, IL-1β, and IL-6) were analyzed by ELISA and RT-PCR methods. Results confirmed that YR-11 peptide inhibited pro-inflammatory cytokines in the sera and hind paw tissues of AIA rats through its suppressive effect on RANKL induced nuclear translocation of NF-κB. The results obtained in this study substantiate the therapeutic benefit of this novel peptide in the prevention of bone loss and inflammation in rheumatoid arthritis with reduced side effects.

Analog-to-digital converter (ADC) plays an important role in mixed signal processingsystems. It serves as an interface between analog and digital signal processingsystems. In the last two decades, circuits implemented in current-modetechnique have drawn lots of interest for sensory systems and integrated circuits.Current-mode circuits have a few vital advantages such as low voltage operation,high speed and wide dynamic ranges. These circuits have wide applications in lowvoltage, high speed-mixed signal processing systems. In this thesis work, a 9-bitpipelined ADC with switch-current (SI) technique is designed and implemented in65 nm CMOS technology. The main focus of the thesis work is to implement thepipelined ADC in SI technique and to optimize the pipelined ADC for low power.The ADC has a stage resolution of 3 bits. The proposed architectures combine adifferential sample-and-hold amplifier, current comparator, binary-to-thermometerdecoder, a differential current-steering digital-to-analog converter, delay logic anddigital error correction block. The circuits are implemented at transistor level in 65nm CMOS technology. The static and dynamic performance metrics of pipelinedADC are evaluated. The simulations are carried out by Cadence Virtuoso SpectreCircuit Simulator 5.10. Matlab is used to determine the performance metrics ofADC.

Objective To evaluate the anti-proliferative and apoptogenic activity of ethyl acetate extract from the leaves of Memecylon edule (EtAc-LME) in MKN-74, NUGC gastric cancer cells and non cancerous gastric mucous cells (GES-1), and to explore the mechanism of EtAc-LME induced apoptosis. Methods The mechanism of EtAc-LME induced apoptosis was explored by analysing the activation of pro-caspases, PARP cleavage, expression of cytochrome-c (Cyt-c) was determined by western blotting, mRNA expression of Bcl-2, Bax by RT-PCR, loss of mitochondrial potential using DiOC6 dye, annexin binding assay and its influence on cell cycle arrest by flow cytometry. Results The results indicated that EtAc-LME inhibited the gastric cancer cell growth in dose-dependent manner and cytotoxicity was more towards the gastric cancer cells (NUGC and MKN-74) compared to normal gastric cells (GES-1), suggesting more specific cytotoxicity to the malignant cells. Over expression of Cyt-c and subsequent activation of caspases-3 and down regulation of Bcl-2 and loss in mitochondrial potential in EtAc-LME treated MKN-74 and NUGC cells suggested that EtAc-LME induced apoptosis by mitochondrial dependent pathway. Conclusions The present findings suggest that ethyl acetate extract of Memecylon edule induces apoptosis selectively in gastric cancer cells emphasizing the importance of this traditional medicine for its potential in the treatment of gastric cancer.