Browsing by Author "Thekkuveettil, A"

Now showing 1 - 6 of 6
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    Autophagy enhancement is rendered ineffective in presence of α-synuclein in melanoma cells
    (J Cell Commun Signal., 2017-07) Nandakumar, S; Vijayan, B; Kishore, A; Thekkuveettil, A
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    Blood brain barrier permeable gold nanocluster for targeted brain imaging and therapy: an in vitro and in vivo study.
    (Journal of Materials Chemistry, 2017-12) Nair, LV; Nair, RV; Shenoy, SJ; Thekkuveettil, A; Jayasree, RS
    Blood brain barrier (BBB) is a dynamic interface, comprising polarized endothelial cells, that separates the brain from the circulatory system. The highly protective nature of this tight junction impairs diagnosis and treatment of brain disorders. In this study, we designed a sub atomic size, near infrared emitting, dual function glutathione gold cluster with high fluorescence yield to facilitate permeability of BBB, for imaging applications and drug delivery. The gold cluster was then modified with Levodopa (L-dopa), to utilize the large amino acid transporter 1 (LAT1) pathways to enhance brain entry. Uptake and permeability of the nanoprobes were demonstrated using an established model of BBB, comprising brain endothelial cells (bEnd.3). The uptake and the clearance of L-dopa modified cluster was faster than the glutathione cluster. L-Dopa modified cluster supports the slow and sustained delivery of a model drug, pilocarpine, to the brain. Results of in vivo imaging and drug release in normal mice hold promise for considering the probe for early diagnosis of brain diseases, when the barrier is not disrupted, and for subsequent drug treatment.
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    Fibroblast-loaded cholecyst-derived scaffold induces faster healing of full thickness burn wound in rabbit
    (JOURNAL OF BIOMATERIALS APPLICATIONS, 2016) Revi, D; Geetha, C; Thekkuveettil, A; Anilkumar, TV
    Graft-assisted healing is often proposed for clinical management of large-sized third-degree cutaneous burn wounds. Skin-graft substitutes prepared by loading appropriate cell types on suitable scaffolds have been found successful. We have previously shown that cholecyst-derived scaffold prepared by a non-detergent/enzymatic method can be used as skin-graft substitute for promoting healing of full thickness excision wounds in rabbit. This article examines the use of this scaffold for preparing bio-artificial grafts by loading homologous fibroblasts. The healing potential was evaluated in a rabbit model of full thickness skin-burn wound. The healing process was evaluated by gross morphology evaluation and histomorphology evaluation at 7, 14 and 28 days of healing. Ex vivo imaging of the wounded tissue was performed and it was found that the loaded fibroblasts remained viable at least for 14 days in the healing wound. By the first week, re-epithelialisation was evident in all animals treated with the cell-loaded graft. Histomorphological wound healing parameters such as the quickness of re-epithelialisation, the nature of collagen deposition and the extent of neo-vascularisation indicated that cell-loaded grafts promoted faster healing of the wounds. Results of immunohistochemistry indicated a parallel change in the number of proliferating cells and myofibroblast in the healing tissue. Although the pathophysiology of the healing reaction was not established, the observations suggested that homologus fibroblast-loaded cholecyst-derived scaffold promoted faster healing of third-degree wounds in rabbit model by modulating myofibroblast response. It was concluded that cholecyst-derived scaffold prepared by the non-detergent/enzymatic method is a potential scaffold for fabricating bioartificial skin grafts.
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    Real Time Imaging and Dynamics of Hippocampal Zn2+ under Epileptic Condition Using a Ratiometric Fluorescent Probe
    (Sci Rep. 2018, 2018-06) Santhakumar, H; Nair, RV; Philips, DS; Shenoy, SJ; Thekkuveettil, A; Ajayaghosh, A; Jayasree, RS
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    Seizure induces activation of multiple subtypes of neural progenitors and growth factors in hippocampus with neuronal maturation confined to dentate gyrus
    (BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 2010) Indulekha, CL; Sanalkumar, R; Thekkuveettil, A; James, J
    Adult hippocampal neurogenesis is altered in response to different physiological and pathological stimuli. GFAP(+ve)/nestin(+ve) radial glial like Type-1 progenitors are considered to be the resident stem cell population in adult hippocampus. During neurogenesis these Type-1 progenitors matures to GFAP(-ve)/nestin(+ve) Type-2 progenitors and then to Type-3 neuroblasts and finally differentiates into granule cell neurons. In our study, using pilocarpine-induced seizure model, we showed that seizure initiated activation of multiple progenitors in the entire hippocampal area such as DG, CA1 and CA3. Seizure induction resulted in activation of two subtypes of Type-1 progenitors, Type-1a (GFAP(+ve)/nestin(+ve)/BrdU(-ve)) and Type-1b (GFAP(+ve)/nestin(+ve)/BrdU(-ve)). We showed that majority of Type-1b progenitors were undergoing only a transition from a state of dormancy to activated form immediately after seizures rather than proliferating, whereas Type-la showed maximum proliferation by 3 days post-seizure induction. Type-2 (GFAP(-ve)/nestin(+ve)/BrdU(+ve)) progenitors were few compared to Type-1. Type-3 (DCX(+ve)) progenitors showed increased expression of immature neurons only in DG region by 3 days after seizure induction indicating maturation of progenitors happens only in microenvironment of DG even though progenitors are activated in CA1 and CA3 regions of hippocampus. Also parallel increase in growth factors expression after seizure induction suggests that microenvironmental niche has a profound effect on stimulation of adult neural progenitors. (C) 2010 Elsevier Inc. All rights reserved.
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    A Simple Method to Efficiently Record/ Capture Caenorhabditis elegans Locomotory Behaviours
    (Protocols.io, 2019-01) Raj, V; Thekkuveettil, A
    Caenorhabditis elegans is an excellent model to study animal chemotaxis and thermotaxis behaviours. These nematodes have highly predictable behaviour pattern towards olfactory cues. A complex chemosensory information processing, based on both temporal and spacial cues, is involved in chemotaxis behaviour and can modify its behaviour towards attractants as well as repellents (Ward., 1973; Colbert et al., 1995; Troemel et al., 1997). In chemotaxis assay, worms show unsurpassed behaviour with a pattern of movement based on concentration gradient in the assay plate (Saeki et al., 2001; Iino et al., 2009). Such behavioural patterns are highly intriguing because they give better understanding on how various neuronal signalling elicit such pattern of behaviour and how factors such as past experience of the animal, mutations affecting neuronal function, modify them. (Brenner., 1974; de Bono et al., 1998). Hence, behavioural assays have critical role in elucidating the alterations in neuronal activities in C. elegans. The standard chemotaxis assay estimates the movement pattern of C. elegans by tracking the course it takes in an agar plate containing a chemical gradient. This measurement requires recording the tracks over time in the plate (Buckingham et al., 2005; Yemini et al., 2011). Automated single worm tracker allows long term behavioural recording (Husson et al., 2005; Wang et al., 2013). The pattern of behaviour of animals in the assay plates shows there are significant alterations in patterns of movement like body bends and omega turns under experimental conditions. For a long term observation for such behaviour one needs to record the animals with least disturbances. Efficient recording often eliminates researcher’s bias and makes it easy to re-evaluate the results if needed (Piere-Shimoura et al., 1999; Hardaker LA et al., 2001; Baek et al., 2002). These recorded videos can be later processed in ImageJ for measuring the patterns. Though these recording can be done using a simple dissection microscopic system with camera, there is a major limitation that the light source is very close to the worm making series of artefacts in its behaviour, Here we report a simple setup to manually record and count these behavioural changes in worms. In this study we measured basal slowing response and enhanced slowing responses, the two different locomotory changes in response to food. Neuronal circuitry underlying these locomotory changes involves dopamine and serotonin (Sawin et al 2000).