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Anatomy Commons™

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Biomedical Engineering and Bioengineering

2011

Articles 1 - 5 of 5

Full-Text Articles in Anatomy

Left Ventricular Assist Devices: Engineering Design Considerations, Marwan A. Simaan, Eduardo Divo, George Faragallah, Yu Wang Aug 2011

Left Ventricular Assist Devices: Engineering Design Considerations, Marwan A. Simaan, Eduardo Divo, George Faragallah, Yu Wang

Publications

Patients with end-stage congestive heart failure awaiting heart transplantation often wait long periods of time (300 days or more on the average) before a suitable donor heart becomes available. The medical community has placed increased emphasis on the use of Left Ventricular Assist Devices or LVADs that can substitute for, or enhance, the function of the natural heart while the patient is waiting for the heart transplant (Poirier, 1997; Frazier & Myers, 1999). Essentially, a rotary LVAD is a pump that operates continuously directing blood from the left ventricle into the aorta by avoiding the aortic valve. Generally speaking, the …

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Ischemia Impairs Vasodilation In Skeletal Muscle Resistance Artery, Kyle Remington Struthers Jun 2011

Ischemia Impairs Vasodilation In Skeletal Muscle Resistance Artery, Kyle Remington Struthers

Master's Theses

Functional vasodilation in arterioles is impaired with chronic ischemia. We sought to examine the impact of chronic ischemia and age on skeletal muscle resistance artery function. To examine the impact of chronic ischemia, the femoral artery was resected from young (2-3mo) and adult (6-7mo) mice and the profunda femoris artery diameter was measured at rest and following gracilis muscle contraction 14 days later using intravital microscopy. Functional vasodilation was significantly impaired in ischemic mice (14.4±4.6% vs. 137.8±14.3%, p<0.0001 n=8) and non-ischemic adult mice (103.0±9.4% vs. 137.8±14.3%, p=0.05 n=10). In order to analyze the cellular mechanisms of the impairment, a protocol was developed to apply pharmacological agents to the experimental preparation while maintaining tissue homeostasis. Endothelial and smooth muscle dependent vasodilation were impaired with ischemia, 39.6 ± 13.6% vs. 80.5 ± 11.4% and 43.0 ± 11.7% vs. 85.1 ± 10.5%, respectively. From this data, it can be supported that smooth muscle dysfunction is the reason for the observed impairment in arterial vasodilation.

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The Influence Of Macrophage Depletion On Ligament Healing, Connie S. Chamberlain, Ellen M. Leiferman, Kayt E. Frisch, Sijian Wang, Xipei Yang, Nico Van Rooijen, Geoff S. Baer, Stacey L. Brickson, Ray Vanderby Jan 2011

The Influence Of Macrophage Depletion On Ligament Healing, Connie S. Chamberlain, Ellen M. Leiferman, Kayt E. Frisch, Sijian Wang, Xipei Yang, Nico Van Rooijen, Geoff S. Baer, Stacey L. Brickson, Ray Vanderby

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Despite a complex cascade of cellular events to reconstruct damaged extracellular matrix (ECM), ligament healing results in a mechanically inferior, scar-like tissue. During normal healing, the number of macrophages significantly increases within the wound site. Then, granulation tissue expands into any residual, normal ligamentous tissue (creeping substitution), resulting in a larger region of healing, greater mechanical compromise, and an inefficient repair process. To study the effects of macrophages on the repair process, bilateral, surgical rupture of their medial collateral ligaments (MCLs) was done on rats. Treatment animals received liposome-encapsulated clodronate, 2 days before rupture to ablate phagocytosing macrophages. Ligaments were …

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The Influence Of Interleukin-4 On Ligament Healing, Connie S. Chamberlain, Ellen M. Leiferman, Kayt E. Frisch, Sijian Wang, Xipei Yang, Stacey L. Brickson, Ray Vanderby Jan 2011

The Influence Of Interleukin-4 On Ligament Healing, Connie S. Chamberlain, Ellen M. Leiferman, Kayt E. Frisch, Sijian Wang, Xipei Yang, Stacey L. Brickson, Ray Vanderby

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Despite a complex cascade of cellular events to reconstruct the damaged extracellular matrix, ligament healing results in a mechanically inferior scarred ligament. During normal healing, granulation tissue expands into any residual normal ligamentous tissue (creeping substitution), resulting in a larger region of healing, greater mechanical compromise and an inefficient repair process. To control creeping substitution and possibly enhance the repair process, the antiinflammatory cytokine, interleukin-4 (IL-4), was administered to rats before and after rupture of their medial collateral ligaments. In vitro experiments showed a time-dependent effect on fibroblast proliferation after IL-4 treatment. In vivo treatments with IL-4 (100 ng/mL IV) …

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Ultrasound Echo Is Related To Stress And Strain In Tendon, Sarah Duenwald, Hirohito Kobayashi, Kayt E. Frisch, Roderic Lakes, Ray Vanderby Jr. Jan 2011

Ultrasound Echo Is Related To Stress And Strain In Tendon, Sarah Duenwald, Hirohito Kobayashi, Kayt E. Frisch, Roderic Lakes, Ray Vanderby Jr.

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

The mechanical behavior of tendons has been well studied in vitro. A noninvasive method to acquire mechanical data would be highly beneficial. Elastography has been a promising method of gathering in vivo tissue mechanical behavior, but it has inherent limitations. This study presents acoustoelasticity as an alternative ultrasound-based method of measuring tendon stress and strain by reporting a relationship between ultrasonic echo intensity (B-mode ultrasound image brightness) and mechanical behavior of tendon in vitro. Porcine digital flexor tendons were cyclically loaded in a mechanical testing system while an ultrasonic echo response was recorded. We report that echo intensity …

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