Browsing by Author "Chandran, S"

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    Cerebellar Sensory Processing Alterations Impact Motor Cortical Plasticity in Parkinson's Disease: Clues from Dyskinetic Patients
    (Cereb. Cortex (2013), 2013-04) Kishore, A; Popa, T; Balachandran, A; Chandran, S; Pradeep, S; Backer, F; Krishnan, S; Meunier, S
    The plasticity of primary motor cortex (M1) in patients with Parkinson's disease (PD) and levodopa-induced dyskinesias (LIDs) is severely impaired. We recently reported in young healthy subjects that inhibitory cerebellar stimulation enhanced the sensorimotor plasticity of M1 that was induced by paired associative stimulation (PAS). This study demonstrates that the deficient sensorimotor M1 plasticity in 16 patients with LIDs could be reinstated by a single session of real inhibitory cerebellar stimulation but not sham stimulation. This was evident only when a sensory component was involved in the induction of plasticity, indicating that cerebellar sensory processing function is involved in the resurgence of M1 plasticity. The benefit of inhibitory cerebellar stimulation on LIDs is known. To explore whether this benefit is linked to the restoration of sensorimotor plasticity of M1, we conducted an additional study looking at changes in LIDs and PAS-induced plasticity after 10 sessions of either bilateral, real inhibitory cerebellar stimulation or sham stimulation. Only real and not sham stimulation had an antidyskinetic effect and it was paralleled by a resurgence in the sensorimotor plasticity of M1. These results suggest that alterations in cerebellar sensory processing function, occurring secondary to abnormal basal ganglia signals reaching it, may be an important element contributing to the maladaptive sensorimotor plasticity of M1 and the emergence of abnormal involuntary movements.
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    Gender influence on selection and outcome of deep brain stimulation for Parkinsons disease
    (ANNALS OF INDIAN ACADEMY OF NEUROLOGY, 2014) Chandran, S; Krishnan, S; Rao, RM; Sarma, SG; Sarma, PS; Kishore, A
    Background: Gender differences exist in Parkinsons disease (PD), both in clinical manifestations and response to medical treatment. We investigated whether gender differences occur in the clinical characteristics of patients selected for bilateral subthalamic nucleus deep brain stimulation (STN DBS) or in the outcome when resource limits influence treatment choices made by patients. Materials and Methods: Fifty-one consecutive patients were evaluated 1 month before, and 12 months after bilateral STN DBS. All patients were rated using Unified Parkinsons Disease Rating Scale, Parkinsons Disease Quality of Life (PDQL) Scale, Addenbrookes Cognitive Examination and Beck Depression Inventory. Results: Pre-operative characteristics did not differ between the genders except for lower doses of drugs (P = 0.03), worse emotional scores in PDQL (P = 0.01) and worse depression (P = 0.03) in women. There was no gender difference in the surgical outcome, except a lesser reduction of dopaminergic drugs in women. Depression and quality of life (QOL) improved equally well in women and men. Conclusion: Bilateral STN DBS is equally efficacious in both genders as a treatment for motor complications of PD and for improving QOL. Women are likely to be undertreated because of more severe dyskinesia and may experience less emotional well-being, and could therefore potentially benefit from earlier surgical treatment.
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    Gender influence on selection and outcome of deep brain stimulation for Parkinson’s disease
    (Annals of Indian Academy of Neurology, 2014-12) Chandran, S; Syam, K; Rao, RM; Sarma, SG; Sarma, PS; Kishore, A
    BACKGROUND: Gender differences exist in Parkinson's disease (PD), both in clinical manifestations and response to medical treatment. We investigated whether gender differences occur in the clinical characteristics of patients selected for bilateral subthalamic nucleus deep brain stimulation (STN DBS) or in the outcome when resource limits influence treatment choices made by patients. MATERIALS AND METHODS: Fifty-one consecutive patients were evaluated 1 month before, and 12 months after bilateral STN DBS. All patients were rated using Unified Parkinson's Disease Rating Scale, Parkinson's Disease Quality of Life (PDQL) Scale, Addenbrooke's Cognitive Examination and Beck Depression Inventory. RESULTS: Pre-operative characteristics did not differ between the genders except for lower doses of drugs (P = 0.03), worse emotional scores in PDQL (P = 0.01) and worse depression (P = 0.03) in women. There was no gender difference in the surgical outcome, except a lesser reduction of dopaminergic drugs in women. Depression and quality of life (QOL) improved equally well in women and men. CONCLUSION: Bilateral STN DBS is equally efficacious in both genders as a treatment for motor complications of PD and for improving QOL. Women are likely to be undertreated because of more severe dyskinesia and may experience less emotional well-being, and could therefore potentially benefit from earlier surgical treatment.
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    Osteogenic efficacy of strontium hydroxyapatite micro-granules in osteoporotic rat model
    (JOURNAL OF BIOMATERIALS APPLICATIONS, 2016) Chandran, S; Babu, SS; Krishnan, VSH; Varma, HK; John, A
    Excessive demineralization in osteoporotic bones impairs its self-regeneration potential following a defect/fracture and is of great concern among the aged population. In this context, implants with inherent osteogenic ability loaded with therapeutic ions like Strontium (Sr2+) may bring forth promising outcomes. Micro-granular Strontium incorporated Hydroxyapatite scaffolds have been synthesized and invivo osteogenic efficacy was evaluated in a long-term osteoporosis-induced aged (LOA) rat model. Micro-granules with improved surface area are anticipated to resorb faster and together with the inherent bioactive properties of Hydroxyapatite with the leaching of Strontium ions from the scaffold, osteoporotic bone healing may be promoted. Long-term osteoporosis-induced aged rat model was chosen to extrapolate the results to clinical osteoporotic condition in the aged. Micro-granular 10% Strontium incorporated Hydroxyapatite synthesized by wet precipitation method exhibited increased invitro dissolution rate and inductively coupled plasma studies confirmed Strontium ion release of 0.01mM, proving its therapeutic potential for osteoporotic applications. Wistar rats were induced to long-term osteoporosis-induced aged model by ovariectomy along with a prolonged induction period of 10 months. Thereafter, osteogenic efficacy of Strontium incorporated Hydroxyapatite micro-granules was evaluated in femoral bone defects in the long-term osteoporosis-induced aged model. Post eight weeks of implantation invivo regeneration efficacy ratio was highest in the Strontium incorporated Hydroxyapatite implanted group (0.92 +/- 0.04) compared to sham and Hydroxyapatite implanted group. Micro CT evaluation further substantiated the improved osteointegration of Strontium incorporated Hydroxyapatite implants from the density histograms. Thus, the therapeutical potential of micro-granular Strontium incorporated Hydroxyapatite scaffolds becomes relevant, especially as bone void fillers in osteoporotic cases of tumor resection or trauma.
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    Strontium Hydroxyapatite scaffolds engineered with stem cells aid osteointegration and osteogenesis in osteoporotic sheep model.
    (Biointerfaces, 2018-02) Chandran, S; Shenoy, SJ; Babu, SS; Nair, RP; Varma, HK; John, A
    Osteoporotic fracture healing is an orthopaedic challenge due to excessive bone resorption and impaired osteogenesis. Majority of currenttreatment strategies focus on regulating bone resorption and the potential application of Mesenchymal Stem Cells (MSCs) in promoting osteogenesis has not been explored much. Furthermore, the present study has put forth a novel approach, wherein the synergistic action of Strontium (Sr) and MSCs in a single implant may facilitate osteoporotic bone healing. Strontium Hydroxyapatite (SrHA) synthesized by wet precipitation was fabricated into tissue engineered Strontium incorporated Hydroxyapatite (cSrHA) using sheep adipose tissue derived MSCs (ADMSCs). Porosity, radiopacity and cytocompatibility of SrHA scaffolds were found appropriate for orthopaedic applications. cSrHA scaffolds exhibited an in vitro Alkaline Phosphatase activity of 20 mol pnp/30 min comparable to that of Hydroxyapatite (HA) – control scaffold, proving its osteogenic efficacy. Implantation studies in sheep osteoporotic model depicted enhanced osteogenic ability with mature lamellar bone formation in cSrHA implanted group, compared to bare HA, SrHA and tissue engineered HA implanted groups. Histomorphometry data substantiated improved osteogenesis on par with material resorption, as cSrHA implanted group exhibited highest regeneration ratio of 0.38 ± 0.05. Density histograms from micro CT further signified the enhanced osteointegrative ability of cSrHA implants. Results of the study depicted the therapeutic potential of cSrHA in osteoporotic bone healing and proposes the use of allogenic ADMSCs for fabricating “Off the Shelf Tissue Engineered Products”