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Your search keyword '"Harishankar, N."' showing total 3 results
Start Over Author "Harishankar, N." Publisher elsevier
3 results on '"Harishankar, N."'

1. Nonclinical toxicology study of recombinant-plasmid DNA anti-rabies vaccines

Author

Kumar, Uday P, Kumara, Dinesh B, Annapurna, VV, Krishna, Prasanna T, Kalyanasundaram, S, Harishankar, N, Jagadeesan, V, Hariharan, S, Naidu, Nadamuni A, Krishnaswamya, Kamala, Rangarajan, PN, Srinivasan, VA, Reddy, GS, and Sesikeran, B

Subjects
Others, National Centre for Science Information (Merged with JRD Library in May 2012)
Abstract

The absence of standard guidelines from National and International regulatory agencies for the safety evaluation of biotechnology products challenges the ingenuity of toxicologists. At present, the development of standard pre-clinical toxicology protocols for Such products is on an individual case basis. The present investigation is an attempt to evaluate the safety profile of the first indigenously developed DNA based anti-rabies vaccine in India. The test compounds were DNA rabies vaccine {DRV (100 mu g)} and combination rabies vaccine (CRV (100 mu g DRV and 1/50 dose of cell culture vaccine)), intended for clinical use by intramuscular route on 1, 7, 14 and 28 day. As per the regular mandatory requirements, the study has been designed to undertake acute (single dose-10 days), sub-chronic (repeat dose-28 days) and chronic (intended clinical dose-120 days) toxicity tests using three dose levels viz. therapeutic, average (2 x therapeutic dose) and highest dose (10 x therapeutic dose) exposure in Swiss Albino mice. The selection of the rodent model viz. Swiss Albino mice is based on affinity and rapid higher antibody response during the efficacy studies. Apart from physical, physiological, clinical, hematological and histopathology profiles of all target organs, the tier-I immunotoxicity parameters have also been monitored. There were no observational adverse effects even at levels of 10 x therapeutic dose administration of DRV and CRV. The procedure also emphasizes on the designing of protocols for the products developed by recombinant technique.

Published
2006

2. Collagen type-I leads to in vivo matrix mineralization and secondary stabilization of Mg-Zr-Ca alloy implants.

Author

Mushahary D, Wen C, Kumar JM, Lin J, Harishankar N, Hodgson P, Pande G, and Li Y

Subjects
3T3 Cells, Absorptiometry, Photon, Animals, Bone Density, Calcium, Magnesium, Mice, Osseointegration, Surface Properties, X-Ray Diffraction, Zinc, Alloys, Calcification, Physiologic, Collagen Type I metabolism, Prostheses and Implants
Abstract

Biodegradable magnesium-zirconia-calcium (Mg-Zr-Ca) alloy implants were coated with Collagen type-I (Coll-I) and assessed for their rate and efficacy of bone mineralization and implant stabilization. The phases, microstructure and mechanical properties of these alloys were analyzed using X-ray diffraction (XRD), optical microscopy and compression test, respectively, and the corrosion behavior was established by their hydrogen production rate in simulated body fluid (SBF). Coll-I extracted from rat tail, and characterized using fourier transform infrared (FT-IR) spectroscopy, was used for dip-coating the Mg-based alloys. The coated alloys were implanted into the femur bones of male New Zealand white rabbits. In vivo bone formation around the implants was quantified by measuring the bone mineral content/density (BMC/BMD) using dual-energy X-ray absorptiometry (DXA). Osseointegration of the implant and new bone mineralization was visualized by histological and immunohistochemical analysis. Upon surface coating with Coll-I, these alloys demonstrated high surface energy showing enhanced performance as an implant material that is suitable for rapid and efficient new bone tissue induction with optimal mineral content and cellular properties. The results demonstrate that Coll-I coated Mg-Zr-Ca alloys have a tendency to form superior trabecular bone structure with better osteoinduction around the implants and higher implant secondary stabilization, through the phenomenon of contact osteogenesis, compared to the control and uncoated ones in shorter periods of implantation. Hence, Coll-I surface coating of Mg-Zr-Ca alloys is a promising method for expediting new bone formation in vivo and enhancing osseointegration in load bearing implant applications., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Published
2014
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3. Mg-Zr-Sr alloys as biodegradable implant materials.

Author

Li Y, Wen C, Mushahary D, Sravanthi R, Harishankar N, Pande G, and Hodgson P

Subjects
Animals, Bone Density drug effects, Bone and Bones drug effects, Bone and Bones pathology, Cell Adhesion drug effects, Cell Death drug effects, Corrosion, Electricity, Humans, Hydrogen analysis, Male, Mechanical Phenomena drug effects, Microscopy, Electron, Scanning, Osteoblasts drug effects, Osteoblasts metabolism, Osteoblasts pathology, Osteoblasts ultrastructure, Rabbits, X-Ray Diffraction, Absorbable Implants, Alloys pharmacology, Biocompatible Materials pharmacology, Magnesium pharmacology, Materials Testing, Strontium pharmacology, Zirconium pharmacology
Abstract

Novel Mg-Zr-Sr alloys have recently been developed for use as biodegradable implant materials. The Mg-Zr-Sr alloys were prepared by diluting Mg-Zr and Mg-Sr master alloys with pure Mg. The impact of Zr and Sr on the mechanical and biological properties has been thoroughly examined. The microstructures and mechanical properties of the alloys were characterized using optical microscopy, X-ray diffraction and compressive tests. The corrosion resistance was evaluated by electrochemical analysis and hydrogen evolution measurement. The in vitro biocompatibility was assessed using osteoblast-like SaOS2 cells and MTS and haemolysis tests. In vivo bone formation and biodegradability were studied in a rabbit model. The results indicated that both Zr and Sr are excellent candidates for Mg alloying elements in manufacturing biodegradable Mg alloy implants. Zr addition refined the grain size, improved the ductility, smoothed the grain boundaries and enhanced the corrosion resistance of Mg alloys. Sr addition led to an increase in compressive strength, better in vitro biocompatibility, and significantly higher bone formation in vivo. This study demonstrated that Mg-xZr-ySr alloys with x and y ≤5 wt.% would make excellent biodegradable implant materials for load-bearing applications., (Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Published
2012
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