Publications by authors named "Don Brown"

Objectives: To provide a foundational methodology for differentiating comorbidity patterns in subphenotypes through investigation of a multi-site dementia patient dataset.

Materials And Methods: Employing the National Clinical Cohort Collaborative Tenant Pilot (N3C Clinical) dataset, our approach integrates machine learning algorithms-logistic regression and eXtreme Gradient Boosting (XGBoost)-with a diagnostic hierarchical model for nuanced classification of dementia subtypes based on comorbidities and gender. The methodology is enhanced by multi-site EHR data, implementing a hybrid sampling strategy combining 65% Synthetic Minority Over-sampling Technique (SMOTE), 35% Random Under-Sampling (RUS), and Tomek Links for class imbalance.

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Article Synopsis
  • A study investigated the prevalence of vestibular disorders in patients with COVID-19 compared to those without the virus using data from the National COVID Cohort Collaborative database.
  • Results showed that individuals with COVID-19 were significantly more likely to experience vestibular disorders, with the highest risk associated with the omicron 23A variant (OR of 8.80).
  • The findings underscore the need for further research on the long-term effects of vestibular disorders in COVID-19 patients and implications for patient counseling.
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Natural patterns of physical activity in youth are characterized by brief periods of exercise of varying intensity interspersed with rest. To better understand systemic physiologic response mechanisms in children and adolescents, we examined five responses [heart rate (HR), respiratory rate (RR), oxygen uptake (V̇O ), carbon dioxide production (V̇CO ), and minute ventilation (V̇E), measured breath-by-breath] to multiple brief exercise bouts (MBEB). Two groups of healthy participants (early pubertal: 17 female, 20 male; late-pubertal: 23 female, 21 male) performed five consecutive 2-min bouts of constant work rate cycle-ergometer exercise interspersed with 1-min of rest during separate sessions of low- or high-intensity (~40% or 80% peak work, respectively).

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Objective: The integrated Translational Health Research Institute of Virginia (iTHRIV) aims to develop an information architecture to support data workflows throughout the research lifecycle for cross-state teams of translational researchers.

Materials And Methods: The iTHRIV Commons is a cross-state harmonized infrastructure supporting resource discovery, targeted consultations, and research data workflows. As the front end to the iTHRIV Commons, the iTHRIV Research Concierge Portal supports federated login, personalized views, and secure interactions with objects in the ITHRIV Commons federation.

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Histologic diagnosis of Barrett's esophagus and esophageal malignancy via probe-based confocal laser endomicroscopy (pCLE) allows for real-time examination of epithelial architecture and targeted biopsy sampling. Although pCLE demonstrates high specificity, sensitivity remains low. This study employs deep learning architectures in order to improve the accuracy of pCLE in diagnosing esophageal cancer and its precursors.

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At least six microRNAs (miRNAs) appear to be encoded by the latency-associated transcript (LAT) of herpes simplex virus type 1 (HSV-1). The gene for ICP0, an important immediate early (IE) viral protein, is anti-sense to, and overlaps with, the region of LAT from which miRNA H2 (miR-H2) is derived. We recently reported that a mutant (McK-ΔH2) disrupted for miR-H2 on the wild-type HSV-1 strain McKrae genomic background has increased ICP0 expression, increased neurovirulence, and slightly more rapid reactivation.

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Aim: Recurrent herpetic stromal keratitis (rHSK), due to an immune response to reactivation of herpes simplex virus (HSV-1), can cause corneal blindness. The development of therapeutic interventions such as drugs and vaccines to decrease rHSK have been hampered by the lack of a small and reliable animal model in which rHSK occurs at a high frequency during HSV-1 latency. The aim of this study is to develop a rabbit model of rHSK in which stress from elevated temperatures increases the frequency of HSV-1 reactivations and rHSK.

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The herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) encodes several microRNAs. One of these, miR-H2, overlaps and is antisense to the ICP0 gene and appears to decrease expression of the ICP0 protein. To determine if miR-H2 plays a role in the HSV-1 latency-reactivation cycle, we constructed a mutant, McK-ΔH2, in which this microRNA has been disrupted without altering the predicted amino acid sequence of ICP0.

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A multiresidue method for the analysis of 168 pesticides in dried powdered ginseng has been developed using acetonitrile or acetone mixture (acetone/cyclohexane/ethyl acetate, 2:1:1 v/v/v) extraction, solid-phase extraction (SPE) cleanup with octyl-bonded silica (C(8)), graphitized carbon black/primary-secondary amine (GCB/PSA) sorbents and toluene, and capillary gas chromatography-mass spectrometry/selective ion monitoring (GC-MS/SIM) or -tandem mass spectrometry (GC-MS/MS). The geometric mean limits of quantitation (LOQs) were 53 and 6 microg/kg for the acetonitrile extraction and 48 and 7 microg/kg for the acetone-based extraction for GC-MS/SIM and GC-MS/MS, respectively. Mean percent recoveries and standard deviations from the ginseng fortified at 25, 100, and 500 microg/kg using GC-MS/SIM were 87 +/- 10, 88 +/- 8, and 86 +/- 10% from acetonitrile extracts and 88 +/- 13, 88 +/- 12, and 88 +/- 14% from acetone mixture extracts, respectively.

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A multiresidue method for the analysis of pesticides in fresh produce has been developed using salt-out acetonitrile extraction, solid-phase dispersive cleanup with octadecyl-bonded silica (C(18)), and graphitized carbon black/primary-secondary amine (GCB/PSA) sorbents and toluene, followed by capillary gas chromatography-mass spectrometry in selected ion monitoring mode (GC-MS/SIM) or -tandem mass spectrometry (GC-MS/MS). Quantitation was determined from calibration curves using matrix-matched standards ranging from 3.3 to 6667 ng/mL with r(2) > 0.

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