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BME 3170 Final Exam Study Guide
1. what are target cells?: different cells have different susceptibilities (cells
most sensitive)
2. thrombus formation that may occur on an implanted device can be deter-
mined by two assessments: directly or indirectly. give an example of each:
- process of blood clot development on artificial surfaces
- indirect: measure the depletion of circulating blood cells and proteins in
response to the implanted response (reduced platelet counts; changes in
clotting factors)
- direct: monitoring blood flow rate and flow geometry around the implant;
assessing how irregularities in blood flow/stagnant regions contribute to clot
development
3. explain why it is difficult to determine if a material is tissue (and
blood) compatible.: tissue
- complex biological interactions (material and environment)
- implant size, shape, and surface properties
- different vascularity and regenerative capabilities
- animals we use don't accurately represent tissue response
blood
- interactions between material and blood vary with blood flow
conditions and exposure time
4. explain an in vitro method to determine tissue compatibility: - direct
contact test
- agar diffusion test
- elution (extract dilution)
5. direct contact test: - specimens of negative/positive controls and the test
article are placed in cultures and incubated
- specimens are removed and the cells are fixed and stained
- dead cells are lost during the fixation process
- toxicity is evaluated by the absence of stained cells
6. agar diffusion test: - specimens are placed in culture mediums containing
2% agar containing red vital stain
- toxicity is evaluated by the loss of the vital stain by the cells
