Nanotechnology-based medical approaches have made tremendous potential for enhancing the treatment efficacy with minimal doses of chemotherapeutic drugs against cancer. In this study, using tamoxifen (Tam), biodegradable antibody conjugated polymeric nanoparticles (NPs) was developed to achieve targeted delivery as well as sustained release of the drug against breast cancer cells. Poly(D,L-lactic-co-glycolic acid) (PLGA) NPs were stabilized by coating with poly(vinyl alcohol) (PVA), and copolymer polyvinyl-pyrrolidone (PVP) was used to conjugate herceptin (antibody) with PLGA NPs for promoting the site-specific intracellular delivery of Tam against HER2 receptor overexpressed breast cancer (MCF-7) cells. The Tam-loaded PVP-PLGA NPs and herceptin-conjugated Tam-loaded PVP-PLGA NPs were characterized in terms of morphology, size, surface charge, and structural chemistry by dynamic light scattering (DLS), Transmission electron microscopy (TEM), ζ potential analysis, 1H nuclear magnetic resonance (NMR), and Fourier transform infrared (FT-IR) spectroscopy. pH-based drug release property and the anticancer activity (in vitro and in vivo models) of the herceptin conjugated polymeric NPs were evaluated by flow cytometry and confocal image analysis. Besides, the extent of cellular uptake of drug via HER2 receptor-mediated endocytosis by herceptin-conjugated Tam-loaded PVP-PLGA NPs was examined. Furthermore, the possible signaling pathway of apoptotic induction in MCF-7 cells was explored by Western blotting, and it was demonstrated that drug-loaded PLGA NPs were capable of inducing apoptosis in a caspase-dependent manner. Hence, this nanocarrier drug delivery system (DDS) not only actively targets a multidrug-resistance (MDR) associated phenotype (HER2 receptor overexpression) but also improves therapeutic efficiency by enhancing the cancer cell targeted delivery and sustained release of therapeutic agents.
BackgroundInfluenza surveillance is an important tool to identify emerging/reemerging strains, and defining seasonality. We describe the distinct patterns of circulating strains of the virus in different areas in India from 2009 to 2013.MethodsPatients in ten cities presenting with influenza like illness in out-patient departments of dispensaries/hospitals and hospitalized patients with severe acute respiratory infections were enrolled. Nasopharangeal swabs were tested for influenza viruses by real-time RT-PCR, and subtyping; antigenic and genetic analysis were carried out using standard assays.ResultsOf the 44,127 ILI/SARI cases, 6,193 (14.0%) were positive for influenza virus. Peaks of influenza were observed during July-September coinciding with monsoon in cities Delhi and Lucknow (north), Pune (west), Allaphuza (southwest), Nagpur (central), Kolkata (east) and Dibrugarh (northeast), whereas Chennai and Vellore (southeast) revealed peaks in October-November, coinciding with the monsoon months in these cities. In Srinagar (Northern most city at 34°N latitude) influenza circulation peaked in January-March in winter months. The patterns of circulating strains varied over the years: whereas A/H1N1pdm09 and type B co-circulated in 2009 and 2010, H3N2 was the predominant circulating strain in 2011, followed by circulation of A/H1N1pdm09 and influenza B in 2012 and return of A/H3N2 in 2013. Antigenic analysis revealed that most circulating viruses were close to vaccine selected viral strains.ConclusionsOur data shows that India, though physically located in northern hemisphere, has distinct seasonality that might be related to latitude and environmental factors. While cities with temperate seasonality will benefit from vaccination in September-October, cities with peaks in the monsoon season in July-September will benefit from vaccination in April-May. Continued surveillance is critical to understand regional differences in influenza seasonality at regional and sub-regional level, especially in countries with large latitude span.
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