Biomedical Engineering and Bioengineering Commons^™

Fluorescein Clearance Kinetics In Blood And Bile Indicates Hepatic Ischemia-Reperfusion Injury In Rats, Joohyun Kim, Yongquiang Yang, Seung-Keun Hong, Jacek Zielonka, Ranjan K. Dash, Said H. Audi, Suresh N. Kumar, Amit Joshi, Michael W. Zimmerman, Johnny C. Hong

Biomedical Engineering Faculty Research and Publications

Quantitative measurement of the degree of hepatic ischemia-reperfusion injury (IRI) is crucial for developing therapeutic strategies for its treatment. We hypothesized that clearance of fluorescent dye through bile metabolism may reflect the degree of hepatic IRI. In this study, we investigated sodium fluorescein clearance kinetics in blood and bile for quantifying the degree of hepatic IRI. Warm ischemia times (WITs) of 0, 30, or 60 min followed by 1 h or 4 h of reperfusion, were applied to the median and lateral lobes of the liver in Sprague-Dawley rats. Subsequently, 2 mg/kg of sodium fluorescein was injected intravenously, and blood …

Intergrader Agreement Of Foveal Cone Topography Measured Using Adaptive Optics Scanning Light Ophthalmoscopy, Niamh Wynne, Jenna A. Cava, Mina Gaffney, Heather Heitkotter, Abigail Scheidt, Jenny L. Reiniger, Jenna Grieshop, Kai Yang, Wolf M. Harmening, Robert F. Cooper, Joseph Carroll

Biomedical Engineering Faculty Research and Publications

The foveal cone mosaic can be directly visualized using adaptive optics scanning light ophthalmoscopy (AOSLO). Previous studies in individuals with normal vision report wide variability in the topography of the foveal cone mosaic, especially the value of peak cone density (PCD). While these studies often involve a human grader, there have been no studies examining intergrader reproducibility of foveal cone mosaic metrics. Here we re-analyzed published AOSLO foveal cone images from 44 individuals to assess the relationship between the cone density centroid (CDC) location and the location of PCD. Across 5 graders with variable experience, we found a measurement error …

The Relationship Between Cerebrovascular Reactivity And Cerebral Oxygenation During Hemodialysis, W. T. Richerson, Brian D. Schmit, D. F. Wolfgram

Biomedical Engineering Faculty Research and Publications

Significance Statement

Patients with ESKD have a high burden of ischemic brain lesions related to decline in cerebral blood flow during hemodialysis. Preliminary studies in patients on hemodialysis noted impairment in cerebrovascular reactivity, a mechanism that regulates cerebral perfusion. We found that lower cerebrovascular reactivity was associated with greater decrease in cerebral oxygen saturation during hemodialysis, particularly when accounting for changes in systemic BP. These results suggest that testing cerebrovascular reactivity could be relevant to characterizing risk of cerebral ischemia during hemodialysis and the potential sequelae of brain injury and cognitive impairment over time.

Background

Patients with kidney failure treated …

Vibrotactile Perception For Sensorimotor Augmentation: Perceptual Discrimination Of Vibrotactile Stimuli Induced By Low-Cost Eccentric Rotating Mass Motors At Different Body Locations In Young, Middle-Aged, And Older Adults, Ella Pomplun, Ashiya Thomas, Erin Corrigan, Valay A. Shah, Leigh A. Mrotek, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Sensory augmentation technologies are being developed to convey useful supplemental sensory cues to people in comfortable, unobtrusive ways for the purpose of improving the ongoing control of volitional movement. Low-cost vibration motors are strong contenders for providing supplemental cues intended to enhance or augment closed-loop feedback control of limb movements in patients with proprioceptive deficits, but who still retain the ability to generate movement. However, it remains unclear what form such cues should take and where on the body they may be applied to enhance the perception-cognition-action cycle implicit in closed-loop feedback control. As a step toward addressing this knowledge …

Reduced Chest Computed Tomography Scan Length For Patients Positive For Coronavirus Disease 2019: Dose Reduction And Impact On Diagnostic Utility, Sara Principi, Stacy D. O'Connor, Frank Luba, Taly Gilat Schmidt

Biomedical Engineering Faculty Research and Publications

Objective

This work aimed to retrospectively evaluate the potential of dose reduction on chest computed tomography (CT) examinations by reducing the longitudinal scan length for patients positive for coronavirus disease 2019 (COVID-19).

Methods

This study used the Personalized Rapid Estimation of Dose in CT (PREDICT) tool to estimate patient-specific organ doses from CT image data. The PREDICT is a research tool that combines a linear Boltzmann transport equation solver for radiation dose map generation with deep learning algorithms for organ contouring. Computed tomography images from 74 subjects in the Medical Imaging Data Resource Center–RSNA International COVID-19 Open Radiology Database data …

The Value Of High Intensity Locomotor Training Applied To Patients With Acute-Onset Neurologic Injury, Meghan Fahey, Gabrielle Brazg, Christopher E. Henderson, Abby Plawecki, Emily H. Lucas, Darcy S. Reisman, Brian D. Schmit, T. George Hornby

Biomedical Engineering Faculty Research and Publications

The purpose of this review is to delineate some of the evidence regarding the effects of exercise intensity during locomotor training in patients with stroke and iSCI. We provide specific definitions of exercise intensity used within the literature, describe methods used to ensure appropriate levels of exertion, and discuss potential adverse events and safety concerns during its application. Further details on the effects of locomotor training intensity on clinical outcomes, and on neuromuscular and cardiovascular function will be addressed as available. Existing literature across multiple studies and meta-analyses reveals that exercise training intensity is likely a major factor that can …

Hepatic Artery Flow, Inspired Oxygen, And Hemoglobin Determine Liver Tissue Saturation Measured With Visible Diffuse Reflectance Spectroscopy (Vis-Drs) In An In Vivo Swine Model, Stylianos Voulgarelis, Faraneh Fathi, Bing Yu, Barbara Palkovic, Nikolaos A. Chatzizacharias, Kenneth P. Allen, Astrid G. Stucke

Biomedical Engineering Faculty Research and Publications

Background

Prompt diagnosis of vascular compromise following pediatric liver transplantation and restoration of oxygen delivery to the liver improves organ survival. vis-DRS allows for real-time measurement of liver tissue saturation.

Methods

The current study used vis-DRS to determine changes in liver saturation during clinically relevant conditions of reduced oxygen delivery. In an in vivo swine model (n = 15), we determined liver tissue saturation (S_tO₂) during stepwise reduction in hepatic artery flow, different inspiratory oxygen fraction (FiO₂), and increasing hemodilution. A custom vis-DRS probe was placed directly on the organ.

Results

Liver tissue …

Training The Responsible Conduct Of Research And Design, Jay R. Goldberg

Biomedical Engineering Faculty Research and Publications

Students Supported by grants from the National Institutes of Health (NIH) are required to complete training in the responsible conduct of research (RCR). This training includes topics such as authorship, handling of data, reporting of results, maintaining confidentiality, and other topics related to the ethical and responsible conduct of research. It prepares students who are supported by NIH research grants for careers involving research.

Neural Correlates Of Multisensory Integration For Feedback Stabilization Of The Wrist, Aaron J. Suminski, Raymond C. Doudlah, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Robust control of action relies on the ability to perceive, integrate, and act on information from multiple sensory modalities including vision and proprioception. How does the brain combine sensory information to regulate ongoing mechanical interactions between the body and its physical environment? Some behavioral studies suggest that the rules governing multisensory integration for action may differ from the maximum likelihood estimation rules that appear to govern multisensory integration for many perceptual tasks. We used functional magnetic resonance (MR) imaging techniques, a MR-compatible robot, and a multisensory feedback control task to test that hypothesis by investigating how neural mechanisms involved in …

Comparison Of Cone Mosaic Metrics From Images Acquired With The Spectralis High Magnification Module And Adaptive Optics Scanning Light Ophthalmoscopy, Niamh Wynne, Heather Heitkotter, Erica N. Woertz, Robert F. Cooper, Joseph Carroll

Biomedical Engineering Faculty Research and Publications

Purpose: To compare cone mosaic metrics derived from adaptive optics scanning light ophthalmoscopy (AOSLO) images with those derived from Heidelberg Engineering SPECTRALIS High Magnification Module (HMM) images.

Methods: Participants with contiguous cone mosaics had HMM imaging performed at locations superior and temporal to the fovea. These images were registered and averaged offline and then aligned to split-detection AOSLO images; 200 × 200-µm regions of interest were extracted from both modalities. Cones were semi-automatically identified by two graders to provide estimates of cone density and spacing.

Results: Thirty participants with contiguous cone mosaics were imaged (10 males, 20 females; age range, …

Eeg And Fmri Coupling And Decoupling Based On Joint Independent Component Analysis (Jica), Nicholas Heugel, Scott A. Beardsley, Einat Liebenthal

Biomedical Engineering Faculty Research and Publications

Background

Meaningful integration of functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) requires knowing whether these measurements reflect the activity of the same neural sources, i.e., estimating the degree of coupling and decoupling between the neuroimaging modalities.

New method

This paper proposes a method to quantify the coupling and decoupling of fMRI and EEG signals based on the mixing matrix produced by joint independent component analysis (jICA). The method is termed fMRI/EEG-jICA.

Results

fMRI and EEG acquired during a syllable detection task with variable syllable presentation rates (0.25–3 Hz) were separated with jICA into two spatiotemporally distinct components, a primary …

Assessment Of Protection Offered By The Nrf2 Pathway Against Hyperoxia-Induced Acute Lung Injury In Nrf2 Knockout Rats, Said H. Audi, Elizabeth R. Jacobs, Taheri Pardis, Swetha Ganesh, Anne V. Clough

Biomedical Engineering Faculty Research and Publications

Nuclear factor erythroid 2-related factor (Nrf2) is a redox-sensitive transcription factor that responds to oxidative stress by activating expressions of key antioxidant and cytoprotective enzymes via the Nrf2-antioxidant response element (ARE) signaling pathway. Our objective was to characterize hyperoxia-induced acute lung injury (HALI) in Nrf2 knock-out (KO) rats to elucidate the role of this pathway in HALI. Adult Nrf2 wildtype (WT), and KO rats were exposed to room air (normoxia) or >95% O₂ (hyperoxia) for 48 h, after which selected injury and functional endpoints were measured in vivo and ex vivo. Results demonstrate that the Nrf2-ARE signaling pathway …

Neural Control Of Stopping And Stabilizing The Arm, Shanie A. L. Jayasinghe, Robert A. Scheidt, Robert L. Sainburg

Biomedical Engineering Faculty Research and Publications

Stopping is a crucial yet under-studied action for planning and producing meaningful and efficient movements. In this review, we discuss classical human psychophysics studies as well as those using engineered systems that aim to develop models of motor control of the upper limb. We present evidence for a hybrid model of motor control, which has an evolutionary advantage due to division of labor between cerebral hemispheres. Stopping is a fundamental aspect of movement that deserves more attention in research than it currently receives. Such research may provide a basis for understanding arm stabilization deficits that can occur following central nervous …

Acute Magnetic Resonance Imaging Predictors Of Chronic Motor Function And Tissue Sparing In Rat Cervical Spinal Cord Injury, Seung-Yi Lee, Brian D. Schmit, Shekar N. Kurpad, Matthew D. Budde

Biomedical Engineering Faculty Research and Publications

Predicting functional outcomes from spinal cord injury (SCI) at the acute setting is important for patient management. This work investigated the relationship of early magnetic resonance imaging (MRI) biomarkers in a rat model of cervical contusion SCI with long-term functional outcome and tissue sparing. Forty rats with contusion injury at C5 at either the spinal cord midline (bilateral) or over the lateral cord (unilateral) were examined using in vivo multi-modal quantitative MRI at 1 day post-injury. The extent of T₂-weighted hyperintensity reflecting edema was greater in the bilateral model compared with the unilateral injury. Diffusion tensor imaging (DTI) …

Visual Oscillation Effects On Dynamic Balance Control In People With Multiple Sclerosis, Lara I. Riem, Scott A. Beardsley, Ahmed Z. Obeidat, Brian Schmit

Biomedical Engineering Faculty Research and Publications

Background: People with multiple sclerosis (PwMS) have balance deficits while ambulating through environments that contain moving objects or visual manipulations to perceived self-motion. However, their ability to parse object from self-movement has not been explored. The purpose of this research was to examine the effect of medial-lateral oscillations of the visual field and of objects within the scene on gait in PwMS and healthy age-matched controls using virtual reality (VR).

Methods: Fourteen PwMS (mean age 49 ± 11 years) and eleven healthy controls (mean age: 53 ± 12 years) participated in this study. Dynamic balance control was assessed while participants …