Engineering Commons^™

Mechanism Of Preconditioning By Isoflurane In Rabbits: A Direct Role For Reactive Oxygen Species, Katsuya Tanaka, Dorothee Weihrauch, Franz Kehl, Lynda M. Ludwig, John F. Ladisa, Judy R. Kersten, Paul S. Pagel, David C. Warltier

Biomedical Engineering Faculty Research and Publications

LARGE quantities of reactive oxygen species (ROS) released during reperfusion after coronary artery occlusion damage proteins responsible for intracellular homeostasis, produce tissue injury, depress contractile function, and increase myocardial infarct size. In contrast, small quantities of ROS may exert beneficial effects during ischemia and reperfusion when released before a prolonged ischemic event. ROS derived from mitochondria during a brief ischemic episode produce preconditioning. Free radical scavengers administered during ischemic preconditioning (IPC) markedly attenuate the protective effect of the preconditioning stimulus on infarct size. These data suggest that IPC is mediated in part by small quantities of ROS released during preconditioning. …

A Rehabilitation Engineering Course For Biomedical Engineers, M. Barbara Silver-Thorn

Biomedical Engineering Faculty Research and Publications

This paper describes an upper division elective course in rehabilitation engineering that addresses prosthetics and orthotics, wheelchair design, seating and positioning, and automobile modifications for individuals with disabilities. Faculty lectures are enhanced by guest lectures and class field trips. Guest lecturers include a prosthetist and a lower extremity amputee client, an engineer/prosthetist specializing in the upper extremity, and a rehabilitation engineer. The lower extremity prosthetist and his client present a case study for prosthetic prescription, fabrication, fitting, alignment, and evaluation. The engineer/prosthetist contrasts body-powered versus externally powered upper extremity prostheses and associated design, fitting, and functional considerations; he also discusses …

Evaluation Of 70/30 D,L-Pla For Use As A Resorbable Interbody Fusion Cage, Jeffrey M. Toth, Mei Wang, Jeffrey L. Scifert, G. Bryan Cornwall, Bradley T. Estes, Howard Seim, Simon Turner

Biomedical Engineering Faculty Research and Publications

Titanium lumbar interbody spinal fusion devices are reported to be 90% effective for single-level lumbar interbody fusion, although radiographic determination of fusion has been debated. Using blinded radiographic, biomechanic, histologic, and statistical measures, researchers in the present study evaluated a radiolucent 70/30 poly(L-lactide-co-D,L-lactide) (70/30 D,L-PLa) interbody fusion device packed with autograft or rhBMP-2 on a collagen sponge in 25 sheep at 3, 6, 12, 18, and 24 months. A trend of increased fusion stiffness, radiographic fusion, and histologic fusion was demonstrated from 3 months to 24 months. Device degradation was associated with a mild to moderate chronic inflammatory response at …

An Automated Coronary Artery Occlusion Device For Stimulating Collateral Development In Vivo, Richard Rys, John F. Ladisa, John P. Tessmer, Weidong Gu, Judy R. Kersten, David C. Warltier, Paul S. Pagel

Biomedical Engineering Faculty Research and Publications

Introduction: Repetitive, brief coronary artery occlusions produce collateral development in experimental animals. This model causes coronary collateralization in a highly reproducible fashion, but the process is very labor intensive. We report the design and use of a fully automated hydraulic coronary occlusion device capable of producing repetitive coronary occlusions and enhancement of coronary collateral development in dogs.

Methods: The device consists of analog electronics that allow adjustment of occlusion number, frequency, pressure and duration, and mechanical components responsible for the coronary occlusion. The motor and piston of the device are coupled to a chronically implanted hydraulic vascular occluder …

Investigation Of Lower-Limb Tissue Perfusion During Loading, Barbara Silver-Thorn

Biomedical Engineering Faculty Research and Publications

An extant tissue indentor used for amputee residual limb tissue indentation studies was modified to include laser Doppler flowmetry (LDF) to enable measurement of tissue perfusion during indentation. This device allows quantitative assessment of the mechanical and physiological response of soft tissues to load, as demonstrated by indentation studies of the lower-limb tissues of young healthy subjects. Potential measures of interest include the relative change in tissue perfusion with load and the time delays associated with the perfusion response during tissue loading and unloading. Such measures may prove useful in future studies of residual limb tissues, improving our understanding of …

Point Of View: Artificial Intervertebral Disc Replacement Using Bioactive Three-Dimensional Fabric, Jeffrey M. Toth

Biomedical Engineering Faculty Research and Publications

No abstract provided.

Histologic Evaluation Of The Efficacy Of Rhbmp-2 Compared With Autograft Bone In Sheep Spinal Anterior Interbody Fusion, Harvinder Sandhu, Jeffrey M. Toth, Ashish Diwan, H. B. Seim Iii, Linda E.A. Kanim, J. Michael Kabo, A. Simon Turner

Biomedical Engineering Faculty Research and Publications

Study Design. The sheep anterior lumbar spinal fusion model was used to study the efficacy of recombinant human bone morphogenetic protein-2 (rhBMP-2)–collagen composite in comparison with autograft to enhance spinal interbody fusion. Comparisons were drawn from temporal radiographic and end-point biomechanical and histologic data.

Objective. To analyze histologically the ability of rhBMP-2 to achieve complete arthrodesis between vertebral bodies.

Summary of Background Data. Studies using rhBMP for enhancement of anterior interbody fusion have used numerous endpoints. However, systematic histologic evaluation of the fusion has not been conducted.

Methods. Twelve sheep underwent single-level anterior lumbar interbody fusion performed with a cylindrical …

Estimation Of Pulmonary Arterial Volume Changes In The Normal And Hypertensive Fawn-Hooded Rat From 3d Micro-Ct Data, Robert C. Molthen, Christian Wieholt, Steven Thomas Haworth, Christopher A. Dawson

Biomedical Engineering Faculty Research and Publications

In the study of pulmonary vascular remodeling, much can be learned from observing the morphological changes undergone in the pulmonary arteries of the rat lung when exposed to chronic hypoxia or other challenges which elicit a remodeling response. Remodeling effects include thickening of vessel walls, and loss of wall compliance. Morphometric data can be used to localize the hemodynamic and functional consequences. We developed a CT imaging method for measuring the pulmonary arterial tree over a range of pressures in rat lungs. X-ray micro-focal isotropic volumetric imaging of the arterial tree in the intact rat lung provides detailed information on …

A Pneumatically Actuated Manipulandum For Neuromotor Control Research, Aaron J Suminski, Kristina M. Ropella, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

Functional magnetic resonance imaging (fMRI) techniques have great potential for identifying which neural structures are involved in the control of goal-directed reaching movements. However, fMRI techniques alone are not capable of probing the neural mechanisms involved in acquisition of novel motor behaviors because such studies require that the moving limb be perturbed in a controlled fashion. We outline a plan to design and develop a non-metallic, pneumatically actuated tool that, along with systems identification techniques and functional magnetic resonance imaging (fMRI), will characterize and quantify how the human central nervous system uses sensory information during practice-based motor learning.

Reengineering Biomedical Engineering Curricula: A New Product Development Approach, Robert A. Scheidt, L. Waples, Kristina M. Ropella

Biomedical Engineering Faculty Research and Publications

Product development engineers in medical industries have created design control procedures to ensure high quality designs that are as error-free as possible. The reason is simple; companies must adhere to certain engineering and manufacturing "best practices" in order to obtain certification of their devices for sale in the US and abroad. We describe here an ongoing effort to apply these industrial "best practices" to the design and implementation of a novel sequence of undergraduate biomedical computing courses within the Department of Bio-medical Engineering at Marquette University (Milwaukee, Wisconsin). We have tightly integrated our industrial advisory board into this design and …

Quasi-Exact Helical Cone Beam Reconstruction For Micro Ct, Jicun Hu, Robert C. Molthen, Roger Johnson, Steven Haworth, Christopher Dawson

Biomedical Engineering Faculty Research and Publications

A cone beam micro-CT system is set up to collect truncated helical cone beam data. This system includes a micro-focal X-ray source, a precision computer-controlled X-Y-Z-theta stage, and an image-intensifier coupled to a large format CCD detector. The helical scanning mode is implemented by rotating and translating the stage while keeping X-ray source and detector stationary. A chunk of bone and a mouse leg are scanned and quasi-exact reconstruction is performed using the approach proposed in J. Hu et al. (2001). This approach introduced the original idea of accessory paths with upper and lower virtual detectors having infinite axial extent. …