Publications by authors named "S Parkar"

Modulation of neurotransmission is key for organismal responses to varying physiological contexts such as during infection, injury, or other stresses, as well as in learning and memory and for sensory adaptation. Roles for cell autonomous neuromodulatory mechanisms in these processes have been well described. The importance of cell non-autonomous pathways for inter-tissue signaling, such as gut-to-brain or glia-to-neuron, has emerged more recently, but the cellular mechanisms mediating such regulation remain comparatively unexplored.

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This study assesses poliovirus type 1 (PV1) immunity in children to inform the contribution of mucosal immunity in and prevention of poliovirus circulation. A community-based study was conducted in periurban Karachi, Pakistan. Randomly selected children (0-15 years of age) received oral poliovirus vaccine (OPV) challenge dose.

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Effective tissue repair requires coordinated intercellular communication to sense damage, remodel the tissue, and restore function. Here, we dissected the healing response in the intestinal mucosa by mapping intercellular communication at single-cell resolution and integrating with spatial transcriptomics. We demonstrated that a risk variant for Crohn's disease, hepatocyte growth factor activator (HGFAC) ArgHis (R509H), disrupted a damage-sensing pathway connecting the coagulation cascade to growth factors that drive the differentiation of wound-associated epithelial (WAE) cells and production of a localized retinoic acid (RA) gradient to promote fibroblast-mediated tissue remodeling.

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Scientific literature suggests that pregnant women are at greater risk of acquiring a more severe form of COVID-19 exposing both mother and child to a higher risk of obstetric and neonatal complications. These include increased hospitalization rates, ICU admissions, or ventilatory support among pregnant women when compared to COVID-19 negative pregnant womenA case-control study was conducted at the Aga Khan University Hospital, Karachi, Pakistan with the objective of evaluating the clinical presentation of COVID-19 in pregnancy and its effect on maternal and neonatal outcomes. Data was retrospectively collected from April 2020 till January 2022 of obstetric patients with COVID-19 positive cases and were compared with COVID-19 negative cases from the same time.

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The relationship between the microbiota profile and exposure to stress is not well understood. Therefore, we used a rat model of unpredictable chronic mild stress (UCMS) to investigate this relationship. Depressive-like behaviors were measured in Female Sprague Dawley rats using the sucrose preference test and the Porsolt swim test.

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