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Your search keyword '"Vijayakumar, Karthik"' showing total 17 results
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17 results on '"Vijayakumar, Karthik"'

1. A Computational Model of Levodopa-Induced Toxicity in Substantia Nigra Pars Compacta in Parkinson's Disease

Author

Muddapu, Vignayanandam R., Vijayakumar, Karthik, Ramakrishnan, Keerthiga, and Chakravarthy, V Srinivasa

Subjects
Quantitative Biology - Neurons and Cognition, Quantitative Biology - Tissues and Organs
Abstract

Parkinson's disease (PD) is caused by the progressive loss of dopaminergic cells in substantia nigra pars compacta (SNc). The root cause of this cell loss in PD is still not decisively elucidated. A recent line of thinking traces the cause of PD neurodegeneration to metabolic deficiency. Due to exceptionally high energy demand, SNc neurons exhibit a higher basal metabolic rate and higher oxygen consumption rate, which results in oxidative stress. Recently, we have suggested that the excitotoxic loss of SNc cells might be due to energy deficiency occurring at different levels of neural hierarchy. Levodopa (LDOPA), a precursor of dopamine, which is used as a symptom-relieving treatment for PD, leads to outcomes that are both positive and negative. Several researchers suggested that LDOPA might be harmful to SNc cells due to oxidative stress. The role of LDOPA in the course of PD pathogenesis is still debatable. We hypothesize that energy deficiency can lead to LDOPA-induced toxicity (LIT) in two ways: by promoting dopamine-induced oxidative stress and by exacerbating excitotoxicity in SNc. We present a multiscale computational model of SNc-striatum system, which will help us in understanding the mechanism behind neurodegeneration postulated above and provides insights for developing disease-modifying therapeutics. It was observed that SNc terminals are more vulnerable to energy deficiency than SNc somas. During LDOPA therapy, it was observed that higher LDOPA dosage results in increased loss of somas and terminals in SNc. It was also observed that co-administration of LDOPA and glutathione (antioxidant) evades LDOPA-induced toxicity in SNc neurons. We show that our proposed model was able to capture LDOPA-induced toxicity in SNc, caused by energy deficiency.

Published
2020

2. A Single-Planner Approach to Multi-Modal Humanoid Mobility

Author

Dornbush, Andrew, Vijayakumar, Karthik, Bardapurkar, Sameer, Islam, Fahad, and Likhachev, Maxim

Subjects
Computer Science - Robotics
Abstract

In this work, we present an approach to planning for humanoid mobility. Humanoid mobility is a challenging problem, as the configuration space for a humanoid robot is intractably large, especially if the robot is capable of performing many types of locomotion. For example, a humanoid robot may be able to perform such tasks as bipedal walking, crawling, and climbing. Our approach is to plan for all these tasks within a single search process. This allows the search to reason about all the capabilities of the robot at any point, and to derive the complete solution such that the plan is guaranteed to be feasible. A key observation is that we often can roughly decompose a mobility task into a sequence of smaller tasks, and focus planning efforts to reason over much smaller search spaces. To this end, we leverage the results of a recently developed framework for planning with adaptive dimensionality, and incorporate the capabilities of available controllers directly into the planning process. The resulting planner can also be run in an interleaved fashion alongside execution so that time spent idle is much reduced.

Published
2018

3. Prevalence of normoalbuminuric chronic kidney disease among individuals with type 2 diabetes mellitus from India

Author

Nair, Abilash, primary, Jayakumari, Chellamma, additional, Gomez, Ramesh, additional, Dipin, Sasidharan, additional, Jayakumar, RV, additional, Vijayakumar, Karthik, additional, Sreenath, Ravindranath, additional, Ajeesh, Thulaseedharan, additional, Jabbar, PuthiyaveettilKhadar, additional, Das, DarvinVamadevan, additional, Gopi, GiriVishnu, additional, and Seena, ThadathilPandarakandy, additional

Published
2023
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8. Cavum vergae and psychiatric illness: substantive or serendipity?

Author

Chandrasekharan Rajasekharan, Sudhakaran Lekshmi, Muralikrishnan Harikrishnan, and Vijayakumar Karthik

Subjects
medicine.medical_specialty, Auditory hallucination, medicine.diagnostic_test, Images In…, business.industry, Neurological examination, General Medicine, medicine.disease, 030227 psychiatry, 03 medical and health sciences, 0302 clinical medicine, medicine.anatomical_structure, Delusion, Schizophrenia, medicine, Postpartum psychosis, Family history, medicine.symptom, Abnormality, Psychiatry, business, 030217 neurology & neurosurgery, Cavum vergae
Abstract

A 38-year-old woman presented with 1-month history of restlessness, decreased sleep, religious song auditory hallucination and delusion of persecution and reference. She had no insight into her illness. She was not on any long-term medications. There was no history of head trauma or exposure to toxins. She suffered from postpartum psychosis during both her pregnancies (8 and 11 years ago) which warranted inpatient treatment with antipsychotics and mood stabilisers. She defaulted treatment both times once she got better and did not experience any recurrence of symptoms until current episode. She had no other comorbidities or significant family history. Her general medical and neurological examination findings were within normal limits. Routine laboratory tests did not reveal any abnormality. A brain MRI diffusion weighted imaging sequence demonstrated cavum vergae (CV, figure 1A) and MRI brain apparent diffusion coefficient sequence showing CV and thinned out cavum septum pellucidum (CSP, figure …

Published
2018

13. The proportion of patients with short duration cough (2-3 weeks) among newly detected smear-positive pulmonary TB patients; the yield of strategic change in the case detection of revised national tuberculosis control programme in an urban community setting of South India

Author

T S Anish, Vijayakumar Karthik, Vijayakumar K, Teena Mary Joy, and Sujina Cheraparambil Muthukkutty

Subjects
education.field_of_study, Tuberculosis in India, medicine.medical_specialty, Pediatrics, Tuberculosis, business.industry, Public health, Population, Context (language use), Guideline, medicine.disease, Health indicator, medicine, education, business, Sampling frame
Abstract

Context: Tuberculosis (TB) is a public health emergency, which challenges the health indicators of India. Revised National Tuberculosis Control Programme (RNTCP) of the country has modified the definition of a pulmonary TB suspect so as to include an additional proportion of people with cough of 2 to 3 weeks duration, which will help in reducing the delay in starting treatment. Aims: To estimate the proportion of people with cough of 2-3 weeks duration among the newly diagnosed sputum-positive TB patients. Settings and Design: It is a community-based, cross-sectional study in the geographical setting of Thiruvanathapuram city corporation area, Kerala, India. Materials and Methods: The defined population in this study was tuberculosis cases registered under RNTCP for 1 year after April 2009 at the Thiruvanathapuram Tuberculosis Unit (TU). Simple random sampling procedure was done from the sampling frame, the registry of sputum-positive pulmonary cases. TB patients were interviewed when they came to the DOTS center to start the treatment. Total duration of treatment was the major outcome variable. The study protocol was approved by institutional ethical committee of government medical college, Thiruvananthapuram. Results: Proportion of people having cough of less than 3 weeks duration among newly detected TB patients and eligible for screening as per the new guideline was 32%. The analysis included data of 194 subjects with a mean (standard deviation) age of 47.5 (14.3) years. Male gender (149, 76.8%), an educational level up to secondary school (172, 88.6%), and people who were either unemployed or manual laborers (96, 49.4%) predominated in the study sample. Conclusions: In short, the study revealed that almost one third of recently diagnosed TB patients would not have been considered as 'TB suspect' before the implementation of the new strategic change. The findings support the new definition of pulmonary TB suspect in RNTCP.

Published
2012

17. Prevalence of normoalbuminuric chronic kidney disease among individuals with type 2 diabetes mellitus from India.

Author

Jayakumari, Chellamma, Gomez, Ramesh, Dipin, Sasidharan, Jayakumar, R. V., Vijayakumar, Karthik, Sreenath, Ravindranath, Ajeesh, Thulaseedharan, Jabbar, Puthiyaveettil Khadar, Das, Darvin Vamadevan, Gopi, Giri Vishnu, Seena, Thadathil Pandarakandy, and Nair, Abilash

Subjects
*TYPE 2 diabetes, *CHRONIC kidney failure, *KIDNEY failure, *DIABETIC nephropathies, *KIDNEY diseases
Abstract

Background & objectives: A subset of diabetic individuals are known to develop progressive renal insufficiency without albuminuria, referred to as normoalbuminuric chronic kidney disease (NACKD). There is, however, a paucity of studies regarding this condition in India. So, this study, aimed to find the prevalence of normoalbuminuric renal dysfunction and its clinical associations in diabetic Indian population. Methods: Medical record search of patients with type 2 diabetes mellitus at a tertiary care centre was done. Based on the urinary albumin:creatinine ratio (>30 mg/g creatinine) and estimated glomerular filtration rate (e-GFR) (<60 ml/min/1.73m2), individuals were classified as having, (i) no kidney disease (NKD), (ii) chronic kidney disease (CKD), (iii) albuminuria alone (ALB), (iv) normoalbuminuric low e-GFR (NACKD) and (v) albuminuria with low e-GFR albuminuric CKD (ACKD). Furthermore, the clinical and biochemical parameters of these groups were also compared. Results: Data from 3534 diabetes patients with a mean age of 53.8±10.9 yr and mean duration of diabetes of 10.3±7.5 yr were available for the analysis. NACKD constituted 39.1 per cent of the patients with reduced e-GFR, NACKD was found in 2.1 per cent and ACKD in 3.4 per cent of all diabetic patients. Compared to NKD patients, was found an independent association between NACKD and higher age, male sex, lower body weight and statin intake but not with glycated haemoglobin, fasting and postprandial plasma glucose. Patients with NACKD were found to be older than those with ACKD. Retinopathy was found to be more prevalent in the ACKD patients, whereas the rates of macrovascular complications were found to be similar between the groups. The prevalence of NACKD relative to ACKD decreased in CKD stages 3b, 4 and 5. Interpretation & conclusions: The results of this study suggest that NACKD constituted greater than one third of patients with diabetes and decreased e-GFR, which showed a strong association with age but not with duration or severity of hyperglycaemia or the presence of retinopathy. Both NACKD and ACKD showed similar associations with macrovascular disease. [ABSTRACT FROM AUTHOR]

Published
2022
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