Publications by authors named "Tapas Nag"

Keratoconus (KC) is characterised by corneal stromal thinning and irregular astigmatism, resulting in diminution of vision. Underlying aetiology remains poorly understood. Recent evidence suggests dysregulation of oxidative balance and mitochondrial function in KC corneas.

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Autophagy is common in the aging retinal pigment epithelium (RPE). A dysfunctional autophagy in aged RPE is implicated in the pathogenesis of age-related macular degeneration. Aging human retina accompanies degenerative changes in photoreceptor mitochondria.

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Article Synopsis
  • - The study investigates the effect of 4-butylcyclohexane carboxylic acid (4-BCCA), a potential epilepsy treatment, in comparison to standard antiseizure medications in a rat model of status epilepticus.
  • - 4-BCCA demonstrated effective seizure control and neuroprotection, with the best results observed when combined with the medication perampanel, showing improved memory retention and neuronal viability.
  • - The findings suggest that 4-BCCA could be a promising therapeutic option for managing seizures and reducing neurodegeneration in epilepsy, warranting further investigation.
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We describe the histological organisation and mucin content in the digestive tract of the stream catfish Pseudecheneis sulcatus. The aim is to find the modifications of the digestive tract in relation to food resources of its habitat. The oesophageal mucosa consists of stratified squamous epithelium with many mucous-secreting cells.

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Myocardial infarction (MI) is irreversible damage to the myocardial tissue caused by prolonged ischemia/hypoxia, subsequently leading to loss of contractile function and myocardial damage. However, after a perilous period, ischemia-reperfusion (IR) itself causes the generation of oxygen free radicals, disturbance in cation homeostasis, depletion of cellular energy stores, and activation of innate and adaptive immune responses. The present study employed Abatacept (ABT), which is an anti-inflammatory drug, originally used as an antirheumatic response agent.

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Background: Congenital inguinal hernia, hydrocele and undescended testis (UDT) are associated with patent processus vaginalis. The smooth muscles present in the processus vaginalis aid in the descent of the testis and undergo programmed cell death after testicular descent leading to obliteration. The persisting amount of smooth muscle in the processus vaginalis influences the clinical outcome as inguinal hernia, hydrocele or UDT.

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Bisphenol A (BPA), a common plasticizer, is categorized as a neurotoxic compound. Its impact on individuals exhibits sex-linked variations. Several biological and environmental factors impact the degree of toxicity.

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Background: Arglabin is a plant alkaloid (sesquiterpene lactone) that is used as an anticancer drug. It has potential anti-diabetic and anti-atherogenic effects.

Purpose: Arglabin has drawn particular attention because of its therapeutic effects as an anti-inflammatory agent in multiple diseases.

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Glutamate induced damage to retinal ganglion cells (RGCs) requires tight physiological regulation of the N-methyl-D-aspartate (NMDA) receptors. Previously, studies have demonstrated the neuroprotective abilities of antioxidants like coenzyme Q (CoQ) and vitamin E analogs like α-tocopherol against neuropathies resulting from NMDA insult, but have failed to shed light on the effect of CoQ and trolox, a hydrophilic analog of vitamin E, on glaucomatous neurodegeneration. In the current study, we wanted to investigate whether the combined effect of trolox with CoQ could alleviate NMDA-induced death of retinal cells while also trying to elucidate the underlying mechanism in relation to the yet unexplained role of vascular endothelial growth factor (VEGF) in NMDA-mediated excitotoxicity.

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Small extracellular vesicles (sEVs) or exosomes are secretory vesicles largely involved in cell-cell communications and found to play a role in development as well as diseases including atherosclerosis. They hold a huge potential for translational research by devising better clinical diagnostics, biomarker discovery, drug delivery, and therapeutic strategies. Variations terms of morphology and distribution are crucial to biological function integrity.

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Article Synopsis
  • The study investigates the role of pigmentation as a prognostic factor in uveal melanoma (UM), focusing on the expression of specific markers (TYRP2, MITF, and SILV) that regulate melanin synthesis.
  • Using transmission electron microscopy and gene expression analysis, the researchers found ultrastructural differences in melanosomes between high-pigmented and low-pigmented UM cases, with higher expression levels of SILV, TYRP2, and MITF in 70% and 58% of the samples, respectively.
  • The findings suggest that these pigmentation markers, particularly MITF, are linked to more aggressive UM behavior and reduced metastatic-free survival, highlighting their potential importance in prognosis and treatment outcomes.
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Müller glial cells (MC) support various metabolic functions of the retinal neurons, and maintain the homeostasis. Oxidative stress is intensified with aging, and in human retina, MC and photoreceptors undergo lipid peroxidation and protein nitration. Information on how MC respond to oxidative stress is vital to understand the fate of aging retinal neurons.

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Many drugs were recommended as antiviral agents for infection control and effective therapy to reduce the mortality rate for COVID-19 patients. Hydroxychloroquine (HCQ), an antimalarial drug, has been controversially recommended for prophylactic use in many countries, including India, to control SARS-CoV-2 infections. We have explored the effect of prophylactic HCQ from the cells of bronchoalveolar lavage fluids from COVID-19-induced acute respiratory distress syndrome patients to determine the level of infection and ultrastructural alterations in the ciliated epithelium, type II pneumocytes, alveolar macrophages, neutrophils, and enucleated granulocytes.

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Sesamol, a lignan obtained from roasted seeds of Sesamum indicum, has high antioxidant and anti-inflammatory activity. In this study, we have investigated the effect of sesamol on Bleomycin (BLM) induced pulmonary toxicity as well as fibrosis in Wistar rats. Lung toxicity was induced by administration of BLM, 0.

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This paper reports on glycogen store in the retinal horizontal cells (HC) of the African mud catfish Clarias gariepinus, as seen by histochemical reaction with periodic acid Schiff (PAS) and transmission electron microscopy in light- as well as dark-adapted state. Glycogen is abundant in the large somata and less in their axons, characterised ultrastructurally by many microtubules and extensive gap junctions interconnecting them. There was no apparent difference in glycogen content in HC somata between light- and dark adaptation, but the axons clearly showed absence of glycogen in dark condition.

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Background: Parkinson's disease (PD) is a progressive neurodegenerative disorder that mainly affects the aged population. Transcranial magnetic field (MF) stimulation has shown to provide temporary motor recovery in neurological disorders.

Purpose: The aim of this study was to understand the cellular and molecular mechanism of low-intensity MF stimulation (17.

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Article Synopsis
  • Cellular therapy using endothelial progenitor cells (EPCs) can help restore damaged tissues by promoting blood vessel formation, but issues like poor survival and migration limit its effectiveness in clinical settings.
  • Co-culturing EPCs with mesenchymal stem cells (MSCs) can enhance the functionality of EPCs, specifically improving their adhesion, migration, and overall vasculogenic ability.
  • Research showed that indirectly primed EPCs (via paracrine signals from MSCs) outperformed directly primed EPCs in migration and proliferation, while also exhibiting reduced inflammation and a well-balanced angiogenesis-related protein signature.
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The overproduction of reactive oxygen species (ROS) has been associated with various human diseases. ROS exert a multitude of biological effects with both physiological and pathological consequences. Monosodium glutamate (MSG), a sodium salt of the natural amino acid glutamate, is a flavor-enhancing food additive, which is widely used in Asian cuisine and is an ingredient that brings out the "umami" meat flavor.

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Stereology and semiautomated binary image histomorphometry are two common methods used for morphometry of nerve fibres. Nucleator probe can be used for the estimation of morphometric parameters like diameter, perimeter, area and volume of a structure that is approximately either a circle or a sphere. In this study, we estimated these parameters with the help of ImageJ software on calibrated transmission electron micrographs.

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Background: Fragment reattachment is the recommended treatment modality in uncomplicated crown fractures. There is a paucity of literature regarding the mechanisms responsible for increased resistance to fracture after fragment rehydration in such cases. Hence, the aim of this proof-of-concept study was to decipher the microscopic changes in the penetration characteristics of resin in tooth fragments after different rehydration protocols.

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Sleep is important for cognitive and physical performance. Sleep deprivation not only affects neural functions but also results in muscular fatigue. A good night's sleep reverses these functional derangements caused by sleep deprivation.

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Insulin-resistant brain state is proposed to be the early sign of Alzheimer's disease (AD), which can be studied in the intracerebroventricular streptozotocin (ICV-STZ) rodent model. ICV-STZ is reported to induce sporadic AD with the majority of the disease hallmarks as phenotype. On the other hand, available experimental evidence has used varying doses of STZ (< 1 to 3 mg/kg) and studied its effect for different study durations, ranging from 14 to 270 days.

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In this study, we examined the cellular infectivity and ultrastructural changes due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in the various cells of bronchoalveolar fluid (BALF) from intubated patients of different age groups (≥60 years and <60 years) and with common comorbidities such as diabetes, liver and kidney diseases, and malignancies. BALF of 79 patients (38 cases >60 and 41 cases <60 years) were studied by light microscopy, immunofluorescence, scanning, and transmission electron microscopy to evaluate the ultrastructural changes in the ciliated epithelium, type II pneumocytes, macrophages, neutrophils, eosinophils, lymphocytes, and anucleated granulocytes. This study demonstrated relatively a greater infection and better preservation of subcellular structures in these cells from BALF of younger patients (<60 years compared with the older patients (≥60 years).

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Background & Objectives: Primary or idiopathic osteonecrosis of femur head (ONFH) is the second most commonly observed cause among Indian patients suffering from ischemic ONFH. Although a number of genetic polymorphisms have been associated with idiopathic ONFH pathogenesis in Korean and Chinese populations, there are no studies in the Indian population. This is an exploratory study designed to implicate in promoter sequence polymorphisms of a critical fibrinolytic system regulator, plasminogen activator inhibitor-1 (PAI-1) gene, in cases of idiopathic osteonecrosis.

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