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The purpose of this paper is to present results from methodologies used in our laboratory that are targeted toward identifying specific brain injury thresholds. Results from studying one form of brain injury, diffuse axonal injury, are presented in this report. Physical models, or surrogates, of the skull-brain complex are used to estimate the relationship(More)
We used a new approach, termed dynamic cortical deformation (DCD), to study the neuronal, vascular, and glial responses that occur in focal cerebral contusions. DCD produces experimental contusion by rapidly deforming the cerebral cortex with a transient, nonablative vacuum pulse of short duration (25 milliseconds) to mimic the circumstances of traumatic(More)
Current models used in our laboratory to assess the migration and traction of a population of cells within biopolymer gels are extended to investigate temporal changes in these parameters during compaction of mechanically constrained gels. The random cell migration coefficient, micro (t) is calculated using a windowing technique by regressing the(More)
The dose-response effects of platelet-derived growth factor BB (PDGF-BB) on rat dermal fibroblast (RDF) behavior in mechanically stressed and unstressed type I collagen and fibrin were investigated using quantitative assays developed in our laboratory. In chemotaxis experiments, RDFs responded optimally (P < 0.05) to a gradient of 10 ng/ml PDGF-BB in both(More)
Although glia have been historically classified as the structurally supporting cells of the central nervous system, their role in tissue mechanics is still largely unstudied. The influence of myelin and glia on the mechanical properties of spinal cord tissue was examined by testing embryonic day 18 chick embryo spinal cords in uniaxial tension following(More)
The transport mechanisms in electroporation-mediated molecular delivery are experimentally investigated and quantified. In particular, the uptake of propidium iodide (PI) into single 3T3 fibroblasts is investigated with time- and space-resolved fluorescence microscopy, and as a function of extracellular buffer conductivity. During the pulse, both the peak(More)
The dura mater is the outermost and most substantial meningial layer of central nervous system (CNS) tissue that acts as a protective membrane for the brain and spinal cord. In animal models of traumatic brain injury and spinal cord injury, mechanical insults are often delivered directly to the dura to injure the underlying tissue. As such, including a(More)
Controlled crosslinking of collagen gels has important applications in cell and tissue mechanics as well as tissue engineering. Genipin is a natural plant extract that has been shown to crosslink biological tissues and to produce color and fluorescence changes upon crosslinking. We have characterized the effects of genipin concentration and incubation(More)
The lack of practicable nonlinear elastic contact models frequently compels the inappropriate use of Hertzian models in analyzing indentation data and likely contributes to inconsistencies associated with the results of biological atomic force microscopy measurements. We derived and validated with the aid of the finite element method force-indentation(More)
Although it is known that the brain can be injured by mechanical forces initiated at the moment of impact during trauma, it is not clear how the physical response of the brain dictates the injury patterns that occur in experimental models of traumatic brain injury. In this study, we investigated the mechanical response of the brain to a technique that(More)