Biology subjects

Callahan, K.

Publications and source records attributed to Callahan, K..

3 recordsLinked to original sources

bioRxiv2022

Prefrontal cortex melanocortin 4 receptors (MC4R) mediate food intake behavior in mice

BackgroundMelanocortin 4 receptor (MC4R) activity in the hypothalamus is crucial for regulation of metabolism and food intake. The peptide ligands for the MC4R are associated with feeding, energy expenditure, and also with complex behaviors that orchestrate energy intake and expenditure, but the downstream neuroanatomical and neurochemical targets associated with these behaviors are elusive. In addition to strong expression in the hypothalamus, the MC4R is highly expressed in the medial prefrontal cortex, a region involved in executive function and decision-making. MethodsUsing viral techniques in genetically modified mice combined with molecular techniques, we identify and describe the neuronal dynamics, and define the effects on feeding behavior of a novel population of MC4R expressing neurons in the infralimbic region of the cortex. ResultsHere, we describe a novel population of MC4R-expressing neurons in the infralimbic (IL) region of the mouse prefrontal cortex that are glutamatergic, receive input from melanocortinergic neurons of the arcuate hypothalamus, and project to multiple regions that coordinate appetitive responses to food-related stimuli. The neurons are depolarized by application of MC4R-specific peptidergic agonist, THIQ. Deletion of MC4R from the IL neurons causes increased food intake and body weight gain and impaired executive function in simple food-related behavior tasks. ConclusionTogether, these data suggest that MC4R neurons of the IL play a critical role in the regulation of food intake.

neuroscience↗

bioRxiv2020

Comparison of the NeuMoDX, Diasorin Simplexa, Cepheid and Roche CDC SARS-CoV 2 EUA assays using nasopharyngeal/nasal swabs in universal transport media (UTM) and sputum and tracheal aspirates

In March 2019 the outbreak of SARS-CoV 2 was officially defined as a pandemic by the World Health Organization and shortly after, the United States Food and Drug Administration (FDA) granted Emergency Use Authorization (EUA) to the Centers for Disease Control (CDC) for reverse transcription polymerase chain reaction (rtPCR) molecular testing for the detection of the SARS-CoV-2 virus from NP swabs. Since then, EUA with relaxed regulations were granted to numerous manufacturers and clinical microbiology laboratories to implement in-house testing assays with nasopharyngeal swabs (NP) and subsequently additional specimen types. Because of supply chain shortages leading to competition for reagents, sustaining any significant volume of testing soon became problematic. As a countermeasure, within several weeks the Henry Ford Microbiology Laboratory validated 4 different rtPCR assays and multiple specimen types using NeuMoDX, Diasorin Simplexa, Cepheid and Roche platforms. The purpose of this study was to analyze the analytic sensitivity of these rtPCR assays with NP/nasal swabs and sputum/tracheal aspirates. Qualitative analytic agreement between the 4 platforms for NP/nasal swabs ranged 95% - 100% overall with no statistically significant difference in threshold cT values. Similar results were obtained with the sputum/tracheal aspirates. These data demonstrate the high accuracy and reproducibility in detection of SARS-CoV 2 between the rtPCR assays performed on 4 different platforms with numerous specimen types.

microbiology↗

bioRxiv2018

Achieving the Endgame: Integrated NTD Case Searches

Trachoma and Guinea Worm Disease (GWD) are neglected tropical diseases (NTDs) slated for elimination as a public health problem and eradication respectively by the World Health Organization. As these programs wind down, uncovering the last remaining cases becomes an urgent priority. In 2010, The Ghana Health Service, along with The Carter Center, Sightsavers, and other partners, conducted integrated case search for cases of both GWD and the last stage of trachoma disease, trachomatous trichiasis (TT), as well as providing treatment for trachoma to meet elimination and eradication targets. House to house case search for both diseases was conducted and two case management strategies were explored: a centralized referral to services method and a Point of Care (POC) delivery method. 835 suspected TT cases were discovered in the centralized method, of which 554 accepted surgery. 482 suspected TT cases were discovered in the POC method and all TT cases accepted surgery in the POC searches. The cost per TT case examined was lower in the POC searches compared to the centralized searches ($19.97 in the POC searches and $20.85 in the centralized searches). Both strategies resulted in high surgical uptake for TT surgery, with average uptakes of 72.4% and 83.9% for the centralized and POC searches respectively. We present here that house to house case search offering services at POC are feasible and a potential tool for elimination and eradication programs nearing their end.\n\nAuthor SummaryTrachoma and Guinea Worm Disease (GWD) are neglected tropical diseases (NTDs) slated for elimination as a public health problem and eradication respectively by the World Health Organization. As these programs wind down, uncovering the last remaining cases becomes an urgent priority in order to confirm that eradiation/elimination targets have been reached. Active case searches are one method of finding these last vestiges of disease. Searches for that look for multiple diseases are referred to as integrated searches. We piloted here integrated case searches for GWD and Trachoma with two case management strategies, a referral approach to a central location, and point of care approach (POC). POC approaches can difficult to implement in low resource settings because they require extensive personnel, financial, and logistical, support. However, POC approaches remove one of the biggest barriers to treatment, time spent traveling to a health center, and thus can improve treatment uptake. We found here that integrated active cases searches with a POC case management approach can be implemented in a low resource setting; and improve acceptance and uptake of trachoma examination and trichiasis surgery respectively without costing much more than the referral case management approach.

epidemiology↗