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Search Results: 1 - 10 of 1969 matches for " Arun Chaudhury "
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Molecular Handoffs in Nitrergic Neurotransmission
Arun Chaudhury
Frontiers in Medicine , 2014, DOI: 10.3389/fmed.2014.00008
Abstract: Postsynaptic density (PSD) proteins in excitatory synapses are relatively immobile components, while there is a structured organization of mobile scaffolding proteins lying beneath the PSDs. For example, shank proteins are located further away from the membrane in the cytosolic faces of the PSDs, facing the actin cytoskeleton. The rationale of this organization may be related to important roles of these proteins as “exchange hubs” for the signaling proteins for their migration from the subcortical cytosol to the membrane. Notably, PSD95 have also been demonstrated in prejunctional nerve terminals of nitrergic neuronal varicosities traversing the gastrointestinal smooth muscles. It has been recently reported that motor proteins like myosin Va play important role in transcytosis of nNOS. In this review, the hypothesis is forwarded that nNOS delivered to subcortical cytoskeleton requires interactions with scaffolding proteins prior to docking at the membrane. This may involve significant role of “shank,” named for SRC-homology (SH3) and multiple ankyrin repeat domains, in nitric oxide synthesis. Dynein light chain LC8–nNOS from acto-myosin Va is possibly exchanged with shank, which thereafter facilitates transposition of nNOS for binding with palmitoyl-PSD95 at the nerve terminal membrane. Shank knockout mice, which present with features of autism spectrum disorders, may help delineate the role of shank in enteric nitrergic neuromuscular transmission. Deletion of shank3 in humans is a monogenic cause of autism called Phelan–McDermid syndrome. One fourth of these patients present with cyclical vomiting, which may be explained by junctionopathy resulting from shank deficit in enteric nitrergic nerve terminals.
Similarity in Transcytosis of nNOSα in Enteric Nerve Terminals and Beta Cells of Pancreatic Islet
Arun Chaudhury
Frontiers in Medicine , 2014, DOI: 10.3389/fmed.2014.00020
Myosin Va but not nNOSα is significantly reduced in jejunal musculomotor nerve terminals in diabetes mellitus
ARUN CHAUDHURY,Jacqueline N. Zanoni
Frontiers in Medicine , 2014, DOI: 10.3389/fmed.2014.00017
Abstract: Nitric oxide (NO) mediated slow inhibitory junction potential (sIJP) and mechanical relaxation after electrical field stimulation is impaired in diabetes mellitus. Externally added NO donor restore nitrergic function, indicating that this reduction result from diminution of NO synthesis within the prejunctional nerve terminals. The present study aimed to investigate two specific aims that may potentially provide pathophysiological insights into diabetic nitrergic neuropathy. Specifically, alteration in nNOSα contents within jejunal nerve terminals and a local subcortical transporter myosin Va was tested sixteen weeks after induction of diabetes by low-dose streptozotocin in male Wistar rats. The results show that diabetic rats, in contrast to vehicle treated animals, have (a) nearly absent myosin Va expression in nerve terminals of axons innervating smooth muscles and (b) significant decrease of myosin Va in neuronal soma of myenteric plexus. In contrast, nNOSα staining in diabetic jejunum neuromuscular strips showed near intact expression in neuronal cell bodies. The space occupancy of nitrergic nerve fibers was comparable between groups. Normal concentration of nNOSα was visualized within a majority of nitrergic terminals in diabetes, suggesting intact axonal transport of nNOSα to distant nerve terminals. These results reveal the dissociation between presences of nNOSα in the nerve terminals but deficiency of its transporter myosin Va in the jejunum of diabetic rats. This significant observation of reduced motor protein myosin Va within jejunal nerve terminals may potentially explain impairment of prejunctional nitric oxide synthesis during electrical field stimulation of diabetic gut neuromuscular strips despite presence of the nitrergic synthetic enzyme nNOSα.
Protective role of the calcium channel blocker amlodipine against mitochondrial injury in ischemia and reperfusion injury of rat liver
Chattopadhyay Pronobesh, , Aher Vaibhav Dagagi, Chaudhury Pallab, Wahi Arun Kumar
Acta Pharmaceutica , 2008, DOI: 10.2478/v10007-008-0022-3
Abstract: Ca2+ accumulation and Ca2+ overloading in mitochondria are responsible for the cell abnormality associated with ischemia and reperfusion injury. The present study was aimed at evaluating the efficacy of the Ca2+ channel blocker amlodipine on the mitochondrial Ca2+ accumulation, mitochondrial antioxidant status and mitochondrial respiratory enzymes in ischemia and reperfusion (I/R) induced liver injury. I/R injury induced mitochondrial damage in rats was assessed in terms of the decrease in activities (p < 0.05) of respiratory marker enzymes (malate dehydrogenase, succinate dehydrogenase and NADH dehydrogenase), mitochondrial antioxidant enzymes (glutathione, superoxide dismutase, catalase), and significant increase (p < 0.05) in the level of lipid peroxidation (LPO) and Ca2+ content. Mitochondrial damage was confirmed by transmission electron microscopic (TEM) examination. Pretreatment with amlodipine effectively counteracted the alteration in mitochondrial enzymes induced by ischemia-reperfusion liver damage. TEM study confirms the restoration of cellular normalcy and the cytoprotective role of amlodipine against I/R induced hepatic injury. On the basis of our findings it may be concluded that amlodipine not only possesses Ca2+ channel antagonist properties but it may also reduce the extent of mitochondrial damage by its antioxidant activity.
Myosin Va Plays a Role in Nitrergic Smooth Muscle Relaxation in Gastric Fundus and Corpora Cavernosa of Penis
Arun Chaudhury, Vivian Cristofaro, Josephine A. Carew, Raj K. Goyal, Maryrose P. Sullivan
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0086778
Abstract: The intracellular motor protein myosin Va is involved in nitrergic neurotransmission possibly by trafficking of neuronal nitric oxide synthase (nNOS) within the nerve terminals. In this study, we examined the role of myosin Va in the stomach and penis, proto-typical smooth muscle organs in which nitric oxide (NO) mediated relaxation is critical for function. We used confocal microscopy and co-immunoprecipitation of tissue from the gastric fundus (GF) and penile corpus cavernosum (CCP) to localize myosin Va with nNOS and demonstrate their molecular interaction. We utilized in vitro mechanical studies to test whether smooth muscle relaxations during nitrergic neuromuscular neurotransmission is altered in DBA (dilute, brown, non-agouti) mice which lack functional myosin Va. Myosin Va was localized in nNOS-positive nerve terminals and was co-immunoprecipitated with nNOS in both GF and CCP. In comparison to C57BL/6J wild type (WT) mice, electrical field stimulation (EFS) of precontracted smooth muscles of GF and CCP from DBA animals showed significant impairment of nitrergic relaxation. An NO donor, Sodium nitroprusside (SNP), caused comparable levels of relaxation in smooth muscles of WT and DBA mice. These normal postjunctional responses to SNP in DBA tissues suggest that impairment of smooth muscle relaxation resulted from inhibition of NO synthesis in prejunctional nerve terminals. Our results suggest that normal physiological processes of relaxation of gastric and cavernosal smooth muscles that facilitate food accommodation and penile erection, respectively, may be disrupted under conditions of myosin Va deficiency, resulting in complications like gastroparesis and erectile dysfunction.
Real World Applications of Machine Learning Techniques over Large Mobile Subscriber Datasets
Jobin Wilson,Chitharanj Kachappilly,Rakesh Mohan,Prateek Kapadia,Arun Soman,Santanu Chaudhury
Computer Science , 2015,
Abstract: Communication Service Providers (CSPs) are in a unique position to utilize their vast transactional data assets generated from interactions of subscribers with network elements as well as with other subscribers. CSPs could leverage its data assets for a gamut of applications such as service personalization, predictive offer management, loyalty management, revenue forecasting, network capacity planning, product bundle optimization and churn management to gain significant competitive advantage. However, due to the sheer data volume, variety, velocity and veracity of mobile subscriber datasets, sophisticated data analytics techniques and frameworks are necessary to derive actionable insights in a useable timeframe. In this paper, we describe our journey from a relational database management system (RDBMS) based campaign management solution which allowed data scientists and marketers to use hand-written rules for service personalization and targeted promotions to a distributed Big Data Analytics platform, capable of performing large scale machine learning and data mining to deliver real time service personalization, predictive modelling and product optimization. Our work involves a careful blend of technology, processes and best practices, which facilitate man-machine collaboration and continuous experimentation to derive measurable economic value from data. Our platform has a reach of more than 500 million mobile subscribers worldwide, delivering over 1 billion personalized recommendations annually, processing a total data volume of 64 Petabytes, corresponding to 8.5 trillion events.
Algorithmic Optimization of BDDs and Performance Evaluation for Multi-level Logic Circuits with Area and Power Trade-offs  [PDF]
Saurabh Chaudhury, Anirban Dutta
Circuits and Systems (CS) , 2011, DOI: 10.4236/cs.2011.23031
Abstract: Binary Decision Diagrams (BDDs) can be graphically manipulated to reduce the number of nodes and hence the area. In this context, ordering of BDDs play a major role. Most of the algorithms for input variable ordering of OBDD focus primarily on area minimization. However, suitable input variable ordering helps in minimizing the power consumption also. In this particular work, we have proposed two algorithms namely, a genetic algorithm based technique and a branch and bound algorithm to find an optimal input variable order. Of course, the node reordering is taken care of by the standard BDD package buddy-2.4. Moreover, we have evaluated the performances of the proposed algorithms by running an exhaustive search program. Experi-mental results show a substantial saving in area and power. We have also compared our techniques with other state-of-art techniques of variable ordering for OBDDs and found to give superior results.
Feasibility and Implications of a Monetary Union in Southeast Asia
Rafi Chaudhury
Michigan Journal of Business , 2009,
Abstract: This study explores the readiness of seven ASEAN countries to adopt a common monetary policy and introduce a common currency. The suitability of the region as an Optimum Currency Area is estimated using an OCA Index developed in Bayoumi & Eichengreen (1997). This study finds that while the countries studied appear to be prepared to adopt a common monetary policy, there are still many opportunities to exploit policy independence in order to improve infrastructure and competitiveness prior to further integration.
A Dual-Model Approach to Measuring Income Convergence Sustainability in European and Asian Emerging Economies
Rafi Chaudhury
Michigan Journal of Business , 2010,
Abstract: The 'tiger' economies of Southeast Asia and the transition economies of Central and Eastern Europe have encountered both rapid growth and considerable upheaval in the past two decades. This study examines the extent to which the two regions have converged to industrialized-country levels of per capita income growth, using the convergence criteria defined in Sala-i-Martin (1996), for the 1992-2007 period. The sustainability of convergence going into the future is estimated using a variant of the balance of payments constrained-growth theory developed in Thirlwall (1979). My findings suggest that both regions exhibit fairly rapid convergence, which is likely to continue in the future due to favorable export demand elasticities, technological diffusion, and total factor productivity.
Reporting for cryptosporidium species in routine stool microscopy
Chaudhury A
Indian Journal of Medical Microbiology , 2001,
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