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Articles by Ajay V. Singh in JoVE
Other articles by Ajay V. Singh on PubMed
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Oxidative Stress and Neurodegenerative Diseases: a Review of Upstream and Downstream Antioxidant Therapeutic Options
Current Neuropharmacology.
Mar, 2009 |
Pubmed ID: 19721819 Free radicals are common outcome of normal aerobic cellular metabolism. In-built antioxidant system of body plays its decisive role in prevention of any loss due to free radicals. However, imbalanced defense mechanism of antioxidants, overproduction or incorporation of free radicals from environment to living system leads to serious penalty leading to neuro-degeneration. Neural cells suffer functional or sensory loss in neurodegenerative diseases. Apart from several other environmental or genetic factors, oxidative stress (OS) leading to free radical attack on neural cells contributes calamitous role to neuro-degeneration. Though, oxygen is imperative for life, imbalanced metabolism and excess reactive oxygen species (ROS) generation end into a range of disorders such as Alzheimer's disease, Parkinson's disease, aging and many other neural disorders. Toxicity of free radicals contributes to proteins and DNA injury, inflammation, tissue damage and subsequent cellular apoptosis. Antioxidants are now being looked upon as persuasive therapeutic against solemn neuronal loss, as they have capability to combat by neutralizing free radicals. Diet is major source of antioxidants, as well as medicinal herbs are catching attention to be commercial source of antioxidants at present. Recognition of upstream and downstream antioxidant therapy to oxidative stress has been proved an effective tool in alteration of any neuronal damage as well as free radical scavenging. Antioxidants have a wide scope to sequester metal ions involved in neuronal plaque formation to prevent oxidative stress. In addition, antioxidant therapy is vital in scavenging free radicals and ROS preventing neuronal degeneration in post-oxidative stress scenario.
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Carbon Nanotube-induced Loss of Multicellular Chirality on Micropatterned Substrate is Mediated by Oxidative Stress
ACS Nano.
Mar, 2014 |
Pubmed ID: 24559311 Carbon nanotubes (CNTs) are receiving much attention in medicine, electronics, consumer products, and next-generation nanocomposites because of their unique nanoscale properties. However, little is known about the toxicity and oxidative stress related anomalies of CNTs on complex multicellular behavior. This includes cell chirality, a newly discovered cellular property important for embryonic morphogenesis and demonstrated by directional migration and biased alignment on micropatterned surfaces. In this study, we report the influence of single-walled carbon nanotubes (SWCNTs) on multicellular chirality. The incubation of human umbilical vein endothelial cells (hUVECs) and mouse myoblasts (C2C12) with CNTs at different doses and time points stimulates reactive oxygen species (ROS) production and intra- and extracellular oxidative stress (OS). The OS-mediated noxious microenvironment influences vital subcellular organelles (e.g., mitochondria and centrosomes), cytoskeletal elements (microtubules), and vinculin rich focal adhesions. The disorientated nuclear-centrosome (NC) axis and centriole disintegration lead to a decreased migration rate and loss of directional alignment on micropatterned surfaces. These findings suggest that CNT-mediated OS leads to loss of multicellular chirality. Furthermore, the in vitro microscale system presented here to measure cell chirality can be extended as a prototype for testing toxicity of other nanomaterials.
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Nanoparticle Enabled Drug Delivery Across the Blood Brain Barrier: in Vivo and in Vitro Models, Opportunities and Challenges
Current Pharmaceutical Biotechnology.
2014 |
Pubmed ID: 24809717 The blood brain barrier (BBB) maintains homeostasis by regulating the transport of chemicals at the brain interface. However, it is also one of the largest obstacles for drug delivery to the central nervous system (CNS). The utilization of nanoparticles as drug delivery vehicles is one potential solution to overcome this barrier. This review highlights the characteristics of the BBB that inhibit the passage of drugs to the brain, evaluates the efficiency of current in vitro models to mimic the BBB, and discusses the use of nanoparticles in both in vivo and in vitro models to enhance drug permeability across the barrier. In addition, this review describes factors that influence the passage of nanoparticles (type of polymers and surfactant coating, nanoparticle size) across the barrier. Protein opsonization and phagocytic activity of the reticuloendothelial system limits the amount of drug delivered to the brain, and this article summarizes methods to circumvent these issues. This paper also reviews literature covering opportunities and challenges provided with current applications of nanoparticle drug delivery systems for diseases of the brain, including cancer, HIV, and Alzheimer's disease.
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