Engineering Commons^™

Post-Acquisition Processing Confounds In Brain Volumetric Quantification Of White Matter Hyperintensities, Ahmed A. Bahrani, Omar M. Al-Janabi, Erin L. Abner, Shoshana H. Bardach, Richard J. Kryscio, Donna M. Wilcock, Charles D. Smith, Gregory A. Jicha

Neurology Faculty Publications

BACKGROUND: Disparate research sites using identical or near-identical magnetic resonance imaging (MRI) acquisition techniques often produce results that demonstrate significant variability regarding volumetric quantification of white matter hyperintensities (WMH) in the aging population. The sources of such variability have not previously been fully explored.

NEW METHOD: 3D FLAIR sequences from a group of randomly selected aged subjects were analyzed to identify sources-of-variability in post-acquisition processing that can be problematic when comparing WMH volumetric data across disparate sites. The methods developed focused on standardizing post-acquisition protocol processing methods to develop a protocol with less than 0.5% inter-rater variance.

RESULTS: A series …

Distinct Patterns Of Default Mode And Executive Control Network Circuitry Contribute To Present And Future Executive Function In Older Adults, Christopher A. Brown, Frederick A. Schmitt, Charles D. Smith, Brian T. Gold

Neuroscience Faculty Publications

Executive function (EF) performance in older adults has been linked with functional and structural profiles within the executive control network (ECN) and default mode network (DMN), white matter hyperintensities (WMH) burden and levels of Alzheimer's disease (AD) pathology. Here, we simultaneously explored the unique contributions of these factors to baseline and longitudinal EF performance in older adults. Thirty-two cognitively normal (CN) older adults underwent neuropsychological testing at baseline and annually for three years. Neuroimaging and AD pathology measures were collected at baseline. Separate linear regression models were used to determine which of these variables predicted composite EF scores at baseline …

A Pilot Study Identifying Brain-Targeting Adaptive Immunity In Pediatric Extracorporeal Membrane Oxygenation Patients With Acquired Brain Injury, Sterling B. Ortega, Poornima Pandiyan, Jana Windsor, Vanessa O. Torres, Uma M. Selvaraj, Amy Lee, Michael Morriss, Fenghua Tian, Lakshmi Raman, Ann M. Stowe

Neurology Faculty Publications

OBJECTIVES: Extracorporeal membrane oxygenation provides short-term cardiopulmonary life support, but is associated with peripheral innate inflammation, disruptions in cerebral autoregulation, and acquired brain injury. We tested the hypothesis that extracorporeal membrane oxygenation also induces CNS-directed adaptive immune responses which may exacerbate extracorporeal membrane oxygenation-associated brain injury.

DESIGN: A single center prospective observational study.

SETTING: Pediatric and cardiac ICUs at a single tertiary care, academic center.

PATIENTS: Twenty pediatric extracorporeal membrane oxygenation patients (0-14 yr; 13 females, 7 males) and five nonextracorporeal membrane oxygenation Pediatric Logistic Organ Dysfunction score matched patients.

INTERVENTIONS: None.

MEASUREMENTS AND MAIN RESULTS: Venous blood samples were …

Distinct White Matter Changes Associated With Cerebrospinal Fluid Amyloid-Β1-42 And Hypertension, Omar M. Al-Janabi, Christopher A. Brown, Ahmed A. Bahrani, Erin L. Abner, Justin M. Barber, Brian T. Gold, Larry B. Goldstein, Richard R. Murphy, Peter T. Nelson, Nathan F. Johnson, Leslie M. Shaw, Charles D. Smith, John Q. Trojanowski, Donna M. Wilcock, Gregory A. Jicha

Sanders-Brown Center on Aging Faculty Publications

BACKGROUND: Alzheimer's disease (AD) pathology and hypertension (HTN) are risk factors for development of white matter (WM) alterations and might be independently associated with these alterations in older adults.

OBJECTIVE: To evaluate the independent and synergistic effects of HTN and AD pathology on WM alterations.

METHODS: Clinical measures of cerebrovascular disease risk were collected from 62 participants in University of Kentucky Alzheimer's Disease Center studies who also had cerebrospinal fluid (CSF) sampling and MRI brain scans. CSF Aβ_1-42 levels were measured as a marker of AD, and fluid-attenuated inversion recovery imaging and diffusion tensor imaging were obtained to assess …

Blood Transfusions In Preterm Infants: Changes On Perfusion Index And Intermittent Hypoxemia, Katrina T. Ibonia, Henrietta S. Bada, Philip M. Westgate, Enrique Gomez Pomar, Prasad Bhandary, Abhijit R. Patwardhan, Elie G. Abu Jawdeh

Pediatrics Faculty Publications

BACKGROUND

Red blood cell (RBC) transfusion decreases intermittent hypoxemia (IH) events beyond the first week of life. This benefit may be related to improved perfusion to the respiratory control network. Perfusion index (PI) is a perfusion measure provided by the pulse oximeter. We hypothesized that the benefit in IH after RBC transfusion is associated with an increase in PI. In addition, we assessed the value of PI and clinical measures in predicting the effect of RBC transfusion on IH.

STUDY DESIGN AND METHODS

We prospectively enrolled infants less than 30 weeks' gestation age. PI and oxygen saturation (SpO₂) …

Walking Speed Differentially Alters Spinal Loads In Persons With Traumatic Lower Limb Amputation, Brad D. Hendershot, Iman Shojaei, Julian C. Acasio, Christopher L. Dearth, Babak Bazrgari

Biomedical Engineering Faculty Publications

Persons with lower limb amputation (LLA) perceive altered motions of the trunk/pelvis during activities of daily living as contributing factors for low back pain. When walking (at a singular speed), larger trunk motions among persons with vs. without LLA are associated with larger spinal loads; however, modulating walking speed is necessary in daily life and thus understanding the influences of walking speed on spinal loads in persons with LLA is of particular interest here. Three-dimensional trunk-pelvic kinematics, collected during level-ground walking at self-selected (SSW) and two controlled speeds (~1.0 and ~1.4 m/s), were obtained for seventy-eight participants: 26 with transfemoral …

Nanoparticle Orientation To Control Rna Loading And Ligand Display On Extracellular Vesicles For Cancer Regression, Fengmei Pi, Daniel W. Binzel, Tae Jin Lee, Zhefeng Li, Meiyan Sun, Piotr G. Rychahou, Hui Li, Farzin Haque, Shaoying Wang, Carlo M. Croce, Bin Guo, B. Mark Evers, Peixuan Guo

Markey Cancer Center Faculty Publications

Nanotechnology offers many benefits, and here we report an advantage of applying RNA nanotechnology for directional control. The orientation of arrow-shaped RNA was altered to control ligand display on extracellular vesicle membranes for specific cell targeting, or to regulate intracellular trafficking of small interfering RNA (siRNA) or microRNA (miRNA). Placing membrane-anchoring cholesterol at the tail of the arrow results in display of RNA aptamer or folate on the outer surface of the extracellular vesicle. In contrast, placing the cholesterol at the arrowhead results in partial loading of RNA nanoparticles into the extracellular vesicles. Taking advantage of the RNA ligand for …

White Matter Hyperintensity Associations With Cerebral Blood Flow In Elderly Subjects Stratified By Cerebrovascular Risk, Ahmed A. Bahrani, David K. Powell, Guoqiang Yu, Eleanor S. Johnson, Gregory A. Jicha, Charles D. Smith

Biomedical Engineering Faculty Publications

Objective: This study aims to add clarity to the relationship between deep and periventricular brain white matter hyperintensities (WMHs), cerebral blood flow (CBF), and cerebrovascular risk in older persons. Methods: Deep white matter hyperintensity (dWMH) and periventricular white matter hyperintensity (pWMH) and regional gray matter (GM) and white matter (WM) blood flow from arterial spin labeling were quantified from magnetic resonance imaging scans of 26 cognitively normal elderly subjects stratified by cerebrovascular disease (CVD) risk. Fluidattenuated inversion recovery images were acquired using a high-resolution 3-dimensional (3-D) sequence that reduced partial volume effects seen with slicebased techniques. Results: dWMHs but not …

Using A Respiratory Navigator Significantly Reduces Variability When Quantifying Left Ventricular Torsion With Cardiovascular Magnetic Resonance, Sean M. Hamlet, Christopher M. Haggerty, Jonathan D. Suever, Gregory J. Wehner, Kristin N. Andres, David K. Powell, Richard J. Charnigo, Brandon K. Fornwalt

Electrical and Computer Engineering Faculty Publications

Background: Left ventricular (LV) torsion is an important indicator of cardiac function that is limited by high inter-test variability (50% of the mean value). We hypothesized that this high inter-test variability is partly due to inconsistent breath-hold positions during serial image acquisitions, which could be significantly improved by using a respiratory navigator for cardiovascular magnetic resonance (CMR) based quantification of LV torsion.

Methods: We assessed respiratory-related variability in measured LV torsion with two distinct experimental protocols. First, 17 volunteers were recruited for CMR with cine displacement encoding with stimulated echoes (DENSE) in which a respiratory navigator was used to measure …

Comparison Of Lumbo-Pelvic Kinematics During Trunk Forward Bending And Backward Return Between Patients With Acute Low Back Pain And Asymptomatic Controls, Iman Shojaei, Elizabeth G. Salt, Quenten L. Hooker, Linda R. Van Dillen, Babak Bazrgari

Biomedical Engineering Faculty Publications

Background—Prior studies have reported differences in lumbo-pelvic kinematics during a trunk forward bending and backward return task between individuals with and without chronic low back pain; yet, the literature on lumbo-pelvic kinematics of patients with acute low back pain is scant. Therefore, the purpose of this study was set to investigate lumbo-pelvic kinematics in this cohort.

Methods—A case-control study was conducted to investigate the differences in pelvic and thoracic rotation along with lumbar flexion as well as their first and second time derivatives between females with and without acute low back pain. Participants in each group completed one …

Effects Of Vocal Fold Nodules On Glottal Cycle Measurements Derived From High-Speed Videoendoscopy In Children, Rita R. Patel, Harikrishnan Unnikrishnan, Kevin D. Donohue

Electrical and Computer Engineering Faculty Publications

The goal of this study is to quantify the effects of vocal fold nodules on vibratory motion in children using high-speed videoendoscopy. Differences in vibratory motion were evaluated in 20 children with vocal fold nodules (5–11 years) and 20 age and gender matched typically developing children (5–11 years) during sustained phonation at typical pitch and loudness. Normalized kinematic features of vocal fold displacements from the mid-membranous vocal fold point were extracted from the steady-state high-speed video. A total of 12 kinematic features representing spatial and temporal characteristics of vibratory motion were calculated. Average values and standard deviations (cycle-to-cycle variability) of …

Effects Of Individualized Centrifugation Training On Orthostatic Tolerance In Men And Women, Nandu Goswami, Joyce Evans, Stefan Schneider, Melanie Von Der Wiesche, Edwin Mulder, Andreas Rössler, Helmut Hinghofer-Szalkay, Andrew P. Blaber

Biomedical Engineering Faculty Publications

AIMS: Exposure to artificial gravity (AG) at different G loads and durations on human centrifuges has been shown to improve orthostatic tolerance in men. However, the effects on women and of an individual-specific AG training protocol on tolerance are not known.

METHODS: We examined the effects of 90 minutes of AG vs. 90 minutes of supine rest on the orthostatic tolerance limit (OTL), using head up tilt and lower body negative pressure until presyncope of 7 men and 5 women. Subjects were placed in the centrifuge nacelle while instrumented and after one-hour they underwent either: 1) AG exposure …

Persistent Hepatic Structural Alterations Following Nanoceria Vascular Infusion In The Rat, Michael T. Tseng, Qiang Fu, Khoua Lor, G. Rafael Fernandez-Botran, Zhong-Bin Deng, Uschi M. Graham, D. Allan Butterfield, Eric A. Grulke, Robert A. Yokel

Chemistry Faculty Publications

Understanding the long-term effects and possible toxicity of nanoceria, a widely utilized commercial metal oxide, is of particular importance as it is poised for development as a therapeutic agent based on its autocatalytic redox behavior. We show here evidence of acute and subacute adverse hepatic responses, after a single infusion of an aqueous dispersion of 85 mg/kg, 30 nm nanoceria into Sprague Dawley rats. Light and electron microscopic evidence of avid uptake of nanoceria by Kupffer cells was detected as early as 1 hr after infusion. Biopersistent nanoceria stimulated cluster of differentiation 3⁺ lymphocyte proliferation that intermingled with nanoceria-containing …

Dopaminergic Modulation Of Memory And Affective Processing In Parkinson Depression, Lee X. Blonder, John T. Slevin, Richard J. Kryscio, Catherine A. Martin, Anders H. Andersen, Charles D Smith, Frederick A. Schmitt

Magnetic Resonance Imaging and Spectroscopy Center Faculty Publications

Depression is common in Parkinson's disease and is associated with cognitive impairment. Dopaminergic medications are effective in treating the motor symptoms of Parkinson's disease; however, little is known regarding the effects of dopaminergic pharmacotherapy on cognitive function in depressed Parkinson patients. This study examines the neuropsychological effects of dopaminergic pharmacotherapy in Parkinsonian depression. We compared cognitive function in depressed and non-depressed Parkinson patients at two time-points: following overnight withdrawal and after the usual morning regimen of dopaminergic medications. A total of 28 non-demented, right-handed patients with mild to moderate idiopathic Parkinson's disease participated. Ten of these patients were depressed according …

Load-Relaxation Properties Of The Human Trunk In Response To Prolonged Flexion: Measuring And Modeling The Effect Of Flexion Angle, Nima Toosizadeh, Maury A. Nussbaum, Babak Bazrgari, Michael L. Madigan

Biomedical Engineering Faculty Publications

Experimental studies suggest that prolonged trunk flexion reduces passive support of the spine. To understand alterations of the synergy between active and passive tissues following such loadings, several studies have assessed the time-dependent behavior of passive tissues including those within spinal motion segments and muscles. Yet, there remain limitations regarding load-relaxation of the lumbar spine in response to flexion exposures and the influence of different flexion angles. Ten healthy participants were exposed for 16 min to each of five magnitudes of lumbar flexion specified relative to individual flexion-relaxation angles (i.e., 30, 40, 60, 80, and 100%), during which lumbar flexion …

Rat Brain Pro-Oxidant Effects Of Peripherally Administered 5 Nm Ceria 30 Days After Exposure, Sarita S. Hardas, Rukhsana Sultana, Govind Warrier, Mo Dan, Rebecca L. Florence, Peng Wu, Eric A. Grulke, Michael T. Tseng, Jason M. Unrine, Uschi M. Graham, Robert A. Yokel, D. Allan Butterfield

Chemistry Faculty Publications

The objective of this study was to determine the residual pro-or anti-oxidant effects in rat brain 30 days after systemic administration of a 5 nm citrate-stabilized ceria dispersion. A ∼4% aqueous ceria dispersion was iv-infused (0 or 85 mg/kg) into rats which were terminated 30 days later. Ceria concentration, localization, and chemical speciation in the brain was assessed by inductively coupled plasma mass spectrometry (ICP-MS), light and electron microscopy (EM), and electron energy loss spectroscopy (EELS), respectively. Pro- or anti-oxidant effects were evaluated by measuring levels of protein carbonyls (PC), 3-nitrotyrosine (3NT), and protein-bound-4-hydroxy-2-trans-nonenal (HNE) in the hippocampus, cortex, and …

Functional Dissociation In Frontal And Striatal Areas For Processing Of Positive And Negative Reward Information, Xun Liu, David K. Powell, Hongbin Wang, Brian T. Gold, Christine R. Corbly, Jane E. Joseph

Neuroscience Faculty Publications

Reward-seeking behavior depends critically on processing of positive and negative information at various stages such as reward anticipation, outcome monitoring, and choice evaluation. Behavioral and neuropsychological evidence suggests that processing of positive (e.g., gain) and negative (e.g., loss) reward information may be dissociable and individually disrupted. However, it remains uncertain whether different stages of reward processing share certain neural circuitry in frontal and striatal areas, and whether distinct but interactive systems in these areas are recruited for positive and negative reward processing. To explore these issues, we used a monetary decision-making task to investigate the roles of frontal and striatal …

Dissociation Of Automatic And Strategic Lexical-Semantics: Functional Magnetic Resonance Imaging Evidence For Differing Roles Of Multiple Frontotemporal Regions, Brian T. Gold, David A. Balota, Sara J. Jones, David K. Powell, Charles D. Smith, Anders H. Andersen

Neuroscience Faculty Publications

Behavioral research has demonstrated three major components of the lexical-semantic processing system: automatic activation of semantic representations, strategic retrieval of semantic representations, and inhibition of competitors. However, these component processes are inherently conflated in explicit lexical-semantic decision tasks typically used in functional magnetic resonance imaging (fMRI) research. Here, we combine the logic of behavioral priming studies and the neurophysiological phenomenon of fMRI priming to dissociate the neural bases of automatic and strategic lexical-semantic processes across a series of three studies. A single lexical decision task was used in all studies, with stimulus onset asynchrony or linguistic relationship between prime and …