Biomedical Engineering and Bioengineering Commons^™

Β-Aminopropionitrile-Induced Reduction In Enzymatic Crosslinking Causes In Vitro Changes In Collagen Morphology And Molecular Composition, Silvia P. Canelón, Joseph M. Wallace

Weldon School of Biomedical Engineering Graduate Student Publications

Type I collagen morphology can be characterized using fibril D-spacing, a metric which describes the periodicity of repeating bands of gap and overlap regions of collagen molecules arranged into collagen fibrils. This fibrillar structure is stabilized by enzymatic crosslinks initiated by lysyl oxidase (LOX), a step which can be disrupted using β-aminopropionitrile (BAPN). Murine in vivo studies have confirmed effects of BAPN on collagen nanostructure and the objective of this study was to evaluate the mechanism of these effects in vitro by measuring D-spacing, evaluating the ratio of mature to immature crosslinks, and quantifying gene expression of type I collagen …

Hydroband: The Continuous Hydration Monitoring System, Karina E. Atkinson, Catherine P. Benedict

Williams Honors College, Honors Research Projects

Dehydration is defined as a mild, moderate, or extreme loss of water in the body. It can result in fever, muscle cramps, headaches, dizziness, or heat stroke in athletes. Ways to determine hydration levels include analysis of the urine, blood, or sweat, body weight changes, skin elasticity tests, and increases in core temperature. Patent search, research journals, and outside studies in the health and fitness market showed that a convenient and continuous hydration monitoring system was not available. Changes in core body temperature proved to be the quickest way to measure hydration levels. The HydroBand system is geared towards athletes …

Biomechanics Of Retinal Venous Pulsations As Indicators Of Intracranial Pressure, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Working Papers

The origin of retinal venous pulsations remains an open problem in physiology and medicine; so too, their exact relationship to intracranial pressure. This study takes a mathematical modeling approach to explore details of blood flow through the eye to reveal the mechanism of pulsations. The intravaginal, intraneural, and intraocular segments of the retinal arteries and veins are modeled as connected resistive-capacitive segments. The analysis incorporates two critical mechanical properties of these small blood vessels, not heretofore studied, which become significant under conditions of negative transmural pressures: (1) dramatically reduced compliance during flattening and (2) cross-sectional shape change as internal volume …

A Potential New Technique To Estimate The Origins Of Focal Atrial Tachycardias From 12-Lead Electrocardiograms, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Background: This brief report presents a potential new technique for locating the sites of origin of focal atrial tachycardias from standard 12-lead electrocardiograms. Methods: Estimated P wave vector coordinates are derived from leads I, aVF, V1 and V2, and mapped to a three dimensional coordinate system in space. A simple graphical method is used to find the back projection of the P wave vector onto the surface of atrial muscle to estimate the most likely site of origin of the tachycardia. Results: Graphical back projection correctly identified foci of atrial tachycardias in 19 of 19 cases described in the most …

Oxygen Transport, Shear Stress, And Metabolism In Perfused Hepatocyte-Seeded Scaffolds With Radial Pore Architecture: Experimental And Computational Analyses, Chijioke Mbanu

Wayne State University Dissertations

Several modalities have been proposed as treatments or temporary stop-gap for patients suffering from liver failure until a suitable organ is available. However there is still an urgent need for an off-the-shelf device that can accommodate clinically relevant cell numbers, be cultured at physiological oxygen tensions and, can be fully integrated into and heal the injured hepatic space. In this study we investigated the effects that convective and direct oxygenation had on hepatocyte functionality, morphology and viability while cultured in bulk 3D chitosan scaffolds and perfusion bioreactor systems. Cylindrical chitosan scaffolds with radial directed pore structures were fabricated by a …

Development Of Carbon Based Neural Interface For Neural Stimulation/Recording And Neurotransmitter Detection, Wenwen Yi

Wayne State University Dissertations

Electrical stimulation and recording of neural cells have been widely used in basic neuroscience studies, neural prostheses, and clinical therapies. Stable neural interfaces that effectively communicate with the nervous system via electrodes are of great significance. Recently, flexible neural interfaces that combine carbon nanotubes (CNTs) and soft polymer substrates have generated tremendous interests. CNT based microelectrode arrays (MEAs) have shown enhanced electrochemical properties compared to commonly used electrode materials such as tungsten, platinum or titanium nitride. On the other hand, the soft polymer substrate can overcome the mechanical mismatch between the traditional rigid electrodes (or silicon shank) and the soft …

The Role Of E-Cadherin Force In The Maintenance Of Homeostasis In Epithelial Acini, Fnu Vani Narayanan

Theses and Dissertations

Numerous three-dimensional model systems have emerged for emulating the biochemical and physiological states of native tissue. Yet little is known about the effects of mechanical forces on cell behavior in the context of an organized tissue structure in three-dimensional cell-culture. Epithelial cells cultured in a three-dimensional environment comprised of extracellular matrix proteins form spheroids of polarized cells. Cellular responses to mechanical cues, generated from dynamic interactions with the extracellular matrix and neighboring cells, are known to influence cellular behavior to a great extent. Previous studies have shown that tumorigenic progression has been frequently linked to the down regulation of E-cadherin, …

Novel Therapeutic Approach For Regulating The Susceptibility Of Epitheliato Adenovirus Infection, Mahmoud Soliman Salem Alghamri

Browse all Theses and Dissertations

Human Adenoviruses (AdVs) are etiologic agents for respiratory tract, digestive tract, heart, and eye infections. Although most AdV infections are self-resolving, some infections progress to acute respiratory disease with up to 50% mortality, particularly in immunosuppressed people. Except for vaccines for serotypes, 4 and 7, serotypes that are prevalent in the military, no vaccines or therapeutics that specifically prevent or treat AdV infection exist. On the other hand, AdV remains the most common vector system used in gene therapy clinical trials worldwide and several AdV vectors show promise in phase III clinical trials. The majority of AdVs use the coxsackievirus …

Modeling Effects Of Diet On Human Gut Microbiota, Richard Thomas Agans

Browse all Theses and Dissertations

The human gut microbiota is integrally involved in the metabolism of nutrients contained within the human diet. Studies into human nutrition have primarily been carried out using human and animal models. These studies are extremely important in our understanding of human nutrition, however, suffer from inherent limitations including unique microbial compositions between individuals, compliance in human studies, inability to carry out mechanistic studies, and inability to interrogate proximal regions of the gut without applying invasive techniques. In vitro gut simulator systems circumvent many of these limitations in animal and human models by allowing control of gut environmental conditions, decreasing variability …

A Functional Analysis Of The 3’ Regulatory Region Of The Immunoglobulin Heavy Chain Gene, Andrew David Snyder

Browse all Theses and Dissertations

The immunoglobulin heavy chain (IGH) locus is partially responsible for immunoglobulin (Ig) production in B cells. The human IGH locus contains two 3’ regulatory regions (3’IghRR) that each contain three enhancers, which are thought to help drive overall transcription of the locus and also influence class switching to alternative Ig isotypes. The hs1.2 enhancer within the 3’IghRR is polymorphic in humans, containing a 53 bp invariant sequence (IS) that can be repeated up to four times. In vitro, the human hs1.2 enhancer is a sensitive target of exogenous chemicals, particularly 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD or dioxin), a potent inhibitor of Ig expression …

The Role Of Interleukin-2 In Directing Vascular Smooth Muscle Cell Function And Its Implications For Understanding The Progression Of Atherosclerosis, Prakash Arumugam

Browse all Theses and Dissertations

Atherosclerosis is an inflammatory disorder of the vasculature leading to the development of plaques within vessel walls. A critical component of atherosclerosis involves migration and proliferation of vascular smooth muscle cells (VSMCs) into the developing plaque, however, its mechanism is not yet understood. Previous studies have reported that IL-2 is deposited within the vasculature and IL-2 accumulates within atherosclerotic plaques due to secretion by infiltrating Th-1 cells. A limited number of studies suggest that VSMCs express a partial IL-2 receptor, comprising the ß and ¿ subunit. This suggests that IL-2 may elicit a physiological response in VSMCs. Considering IL-2’s proliferative …

Interaction Of Due-B And Treslin During The Initiation Of Dna Replication, Sumeet Poudel

Browse all Theses and Dissertations

The initiation of DNA replication is a highly regulated and coordinated process. To ensure that the entire genome is replicated only once per cell cycle, many replication proteins are assembled on the chromatin in a step-wise and cell cycle dependent manner. This process is controlled by interaction of replication proteins, post-translational modifications of the replication factors, control of cellular localization of the proteins, or replication factor degradation after their function terminates. Two kinases, CDK (cyclin dependent kinase) and DDK (Dbf4/Drf1 dependent kinase), play important roles during the initiation stage of DNA replication. The c-myc DNA unwinding element-binding protein (DUE-B) is …

Comparison Of Vascular Pulsatility In The Native Beating Heart Versus Direct Mechanical Ventricular Actuation Support Of The Fibrillating Heart, Nathan Victor Wright

Browse all Theses and Dissertations

Most conventional cardiac assist devices today employ continuous flow blood pumps to supplement function in the dysfunctional heart. Continuous flow pumps are predominantly preferred to the original pulsatile pumps due to the smaller size (greater implantability) and higher efficiency they achieve. However, interest in the impact of vascular pulsatility on human health has arisen from the growing evidence of higher complications with nonpulsatile devices compared to pulsatile devices. Direct cardiac compression (DCC) offers a unique solution to the pulsatility issue through the application of force directly to the heart's surface. It is believed that employing the existing pump architecture of …

Evidence That Myo-Inositol Plus Ethanolamine Elevates Plasmalogen Levels And Lends Protection Against Oxidative Stress In Neuro-2a Cells, Isaie Sibomana

Browse all Theses and Dissertations

Plasmalogens are glycerophospholipids abundant in brain and heart tissues. Evidence suggests that they have antioxidant properties. Studies from our laboratory showed that rats treated with myo-inositol plus ethanolamine (ME) have elevated ethanolamine plasmalogens (PE-Pls) in brain and are protected against phosphine-induced oxidative stress. We hypothesized that ME elevates PE-Pls levels and protects against oxidative stress through oxidation of its vinyl ether bond. We tested this hypothesis in Neuro-2A cell culture and assessed the effects of treatments with myo-inositol (M), ethanolamine (Etn), or a combination (ME) on the: (1) effects on phospholipid (PL) classes, especially Etn PLs; (2) effects on cell …

Design And Evaluation Of A Fiber Optic Shape Tracker For Use As A Navigational Aid In Endovascular Guidewires And Catheters, Benjamin Stewart Rinehart

Browse all Theses and Dissertations

Endovascular intervention is the current gold-standard for screening and treating aortic aneurysms and complications caused by peripheral vascular disease (PAD). A typical endovascular procedure begins with inserting an endovascular guidewire into the femoral artery via incision. A catheter is then threaded over the guidewire and both tools are then navigated to the treatment site. The navigation is guided solely by fluoroscopy (x-ray) imagery that is performed throughout the duration of the procedure. Not only does this method provide limited 2-D guidance, but also exposes the patient and medical staff to high levels of radiation. This thesis research focuses on the …

Refining A Post-Stroke Pharmacological And Physical Treatment To Reduce Infarct Volume Or Improve Functional Recovery, Using Gene Expression Changes In The Peri-Infarct Region To Examine Potential Mechanisms In Male And Female Rats, Moner A. Ragas

Browse all Theses and Dissertations

Stroke, a life-threatening medical condition, is the fifth-leading cause of death in the United States with an estimated annual cost of treatments above $70 billion. A combination of innovative approaches was used in our lab to optimize the pre-clinical stroke research design by choosing the most appropriate animal model and methodologies to increase the translational capability of the stroke research. The first study, modeled after ongoing clinical trials using fluoxetine, refined the appropriate timing of fluoxetine and ascorbic acid delivery if a rat was on simvastatin for 7 days pre-stroke and throughout the remainder of the study. Administration of fluoxetine …

Co-Transplantation Of Endothelial Progenitor Cells And Neural Progenitor Cells For Treating Ischemic Stroke In A Mouse Model, Jinju Wang

Browse all Theses and Dissertations

Ischemic stroke (IS) is a major cause of death and disability with limited and less effective therapeutics. Transplantation of stem cells, such as neuronal progenitor cells (NPCs) and endothelial progenitor cells (EPCs), is promising for treating IS. It is well known that neurogenesis and angiogenesis are critical for cerebral repair following ischemic injury. However, whether co-transplantation of EPCs and NPCs has synergistic effects remains unclarified. In addition, the PI3K/Akt pathway participates in modulating a widely range of cellular functions such as anti-apoptotic and anti-oxidant. The signal pathways responsible for the effects of grafted NPCs and EPCs are also waiting for …

Effects Of Scattering And Absorption On Laser Speckle Contrast Imaging, Kosar Khaksari

Dissertations, Master's Theses and Master's Reports

Laser Speckle Contrast Imaging (LSCI) is a real-time, non-invasive method in used to investigate blood flow and perfusion in biological tissues with high temporal and spatial resolution. A reduction in speckle contrast due to particle motion is the primary contrast mechanism in LSCI. Motion results in speckle fluctuations in time and reduces the contrast over a given camera integration period. There are a variety of parameters that effect contrast besides motion. The optical properties of the scattering medium are one of the parameters effecting LSCI values. Changes in blood hematocrit levels manifest as changes in optical properties. In this work, …

Design And Development Of Optical Elastography Setup, Abhinav Madhavachandran

Dissertations, Master's Theses and Master's Reports

The mechanical properties of the skin are an indication of its physiological condition. The properties can serve as potential information for dermatologists for diagnosis and qualitative assessment. Elastography is a medical imaging modality developed to extract the elastic properties of a tissue by application of an external force. Optical elastography is a technique of elastography which uses laser speckle tracking to study the elastic properties of several soft tissue including skin.

This work is aimed at developing an optical elastography setup that can study the elastic properties of skin. The setup includes an imaging system and a force-application system controlled …

Analysis Of Vocal Fold Kinematics Using High Speed Video, Harikrishnan Unnikrishnan

Theses and Dissertations--Electrical and Computer Engineering

Vocal folds are the twin in-folding of the mucous membrane stretched horizontally across the larynx. They vibrate modulating the constant air flow initiated from the lungs. The pulsating pressure wave blowing through the glottis is thus the source for voiced speech production. Study of vocal fold dynamics during voicing are critical for the treatment of voice pathologies. Since the vocal folds move at 100 - 350 cycles per second, their visual inspection is currently done by strobosocopy which merges information from multiple cycles to present an apparent motion. High Speed Digital Laryngeal Imaging(HSDLI) with a temporal resolution of up to …