Browsing by Author "Ranjith, G"

Now showing 1 - 4 of 4
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    A Potential Biomarker in Amyotrophic Lateral Sclerosis: Can Assessment of Brain Iron Deposition with SWI and Corticospinal Tract Degeneration with DTI Help?
    (AMERICAN JOURNAL OF NEURORADIOLOGY, 2016) Sheelakumari, R; Madhusoodanan, M; Radhakrishnan, A; Ranjith, G; Thomas, B
    BACKGROUND AND PURPOSE: Iron-mediated oxidative stress plays a pivotal role in the pathogenesis of amyotrophic lateral sclerosis. This study aimed to assess iron deposition qualitatively and quantitatively by using SWI and microstructural changes in the corticospinal tract by using DTI in patients with amyotrophic lateral sclerosis. MATERIALS AND METHODS: Seventeen patients with amyotrophic lateral sclerosis and 15 age- and sex-matched controls underwent brain MR imaging with SWI and DTI. SWI was analyzed for both signal-intensity scoring and quantitative estimation of iron deposition in the anterior and posterior banks of the motor and sensory cortices and deep gray nuclei. The diffusion measurements along the corticospinal tract at the level of pons and medulla were obtained by ROI analysis. RESULTS: Patients with amyotrophic lateral sclerosis showed reduced signal-intensity grades in the posterior bank of the motor cortex bilaterally. Quantitative analysis confirmed significantly higher iron content in the posterior bank of the motor cortex in patients with amyotrophic lateral sclerosis. In contrast, no significant differences were noted for the anterior bank of the motor cortex, anterior and posterior banks of the sensory cortex, and deep nuclei. Receiver operating characteristic comparison showed a cutoff of 35g Fe/g of tissue with an area under the curve of 0.78 (P = .008) for the posterior bank of the motor cortex in discriminating patients with amyotrophic lateral sclerosis from controls. Fractional anisotropy was lower in the pyramidal tracts of patients with amyotrophic lateral sclerosis at the pons and medulla on either side, along with higher directionally averaged mean diffusivity values. The combination of SWI and DTI revealed an area under the curve of 0.784 for differentiating patients with amyotrophic lateral sclerosis from controls. CONCLUSIONS: Measurements of motor cortex iron deposition and diffusion tensor parameters of the corticospinal tract may be useful biomarkers for the diagnosis of clinically suspected amyotrophic lateral sclerosis.
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    Development of Annuloplasty ring for Mitral Valve Correction (Project - 8128 )
    (SCTIMST, 2022-03-31) Ranjith, G; Vivek, Pillai; Muraleedharan, CV; Umashankar; Ramesh, Babu
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    Hysteresis In CaMKII activity: A Stochastic Model
    (2014 INTERNATIONAL CONFERENCE ON ADVANCES IN COMPUTING, COMMUNICATIONS AND INFORMATICS (ICACCI), 2014) Arun, AV; Ranjith, G; Omkumar, RV
    Calcium/calmodulin dependent protein kinase II (CaMKII) plays a crucial role in the induction of Long Term Potentiation. Several mathematical models have been developed to predict the activity levels of CaMKII in the physiological condition and its molecular switch properties. This paper attempts to study the hysteresis property of CaMKII using a stochastic model. It was observed that hysteresis exists under physiological conditions, but the width of the hysteresis band depends on the concentration of protein phosphatase 1 (PPl). The hysteresis band was maximum at low concentrations of PPI and reduced with increasing concentrations of PPI. It was also observed that the number of phosphorylated subunits saturates beyond a threshold value of calcium signal.
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