{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/85491"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/85491","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"In Vivo Fluorometric Assessment of the Skin Microcirculation","abstract":"A tissue uptake model was developed to describe the fluorescein dermofluorometer signal in terms of the local blood flow and capillary permeability. The fluorescein signal is characterized by a wash-in time constant dependent on both the blood flow and permeability. Under flow-limited conditions the wash-in time constant is inversely proportional to the blood flow only. Significant differences in the fluorescein wash-in time constant were measured between diabetic and non-diabetic subjects (p < 0.10) and between diabetic patients with chronic foot ulcers and those without ulcers (p < 0.01). A new technique, dual dye dermofluorometry, which measures the simultaneous signals from an intravascular tracer, indocyanine green, and a diffusible tracer, sodium fluorescein, was developed. The indocyanine green signal is described by a physiologically-based pharmacokinetic model with a wash-in time constant inversely proportional to the blood flow. The extravascular fluorescein signal is extracted from the observed signal by subtracting a scaled version of the indocyanine green signal. Indocyanine green wash-in time constants were significantly different between patients whose foot ulcers led to amputation relative to those whose foot ulcers healed without surgery (p < 0.10) and between patients with past foot ulcers relative to patients with no history of foot ulcers (p < 0.05). It was determined that while the flow-limited assumption for fluorescein was valid in healthy rat skin, it was not valid in diabetic subjects.","abstract_html":"A tissue uptake model was developed to describe the fluorescein dermofluorometer signal in terms of the local blood flow and capillary permeability. The fluorescein signal is characterized by a wash-in time constant dependent on both the blood flow and permeability. Under flow-limited conditions the wash-in time constant is inversely proportional to the blood flow only. Significant differences in the fluorescein wash-in time constant were measured between diabetic and non-diabetic subjects (p &lt; 0.10) and between diabetic patients with chronic foot ulcers and those without ulcers (p &lt; 0.01). A new technique, dual dye dermofluorometry, which measures the simultaneous signals from an intravascular tracer, indocyanine green, and a diffusible tracer, sodium fluorescein, was developed. The indocyanine green signal is described by a physiologically-based pharmacokinetic model with a wash-in time constant inversely proportional to the blood flow. The extravascular fluorescein signal is extracted from the observed signal by subtracting a scaled version of the indocyanine green signal. Indocyanine green wash-in time constants were significantly different between patients whose foot ulcers led to amputation relative to those whose foot ulcers healed without surgery (p &lt; 0.10) and between patients with past foot ulcers relative to patients with no history of foot ulcers (p &lt; 0.05). It was determined that while the flow-limited assumption for fluorescein was valid in healthy rat skin, it was not valid in diabetic subjects.","abstract_has_math":false,"creators":["Oh, Deborah Kyung"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Biophysics and Computational Biology","degree_department":null,"school":null,"contributors":["Richard L. 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The fluorescein signal is characterized by a wash-in time constant dependent on both the blood flow and permeability. Under flow-limited conditions the wash-in time constant is inversely proportional to the blood flow only. Significant differences in the fluorescein wash-in time constant were measured between diabetic and non-diabetic subjects (p < 0.10) and between diabetic patients with chronic foot ulcers and those without ulcers (p < 0.01). A new technique, dual dye dermofluorometry, which measures the simultaneous signals from an intravascular tracer, indocyanine green, and a diffusible tracer, sodium fluorescein, was developed. The indocyanine green signal is described by a physiologically-based pharmacokinetic model with a wash-in time constant inversely proportional to the blood flow. The extravascular fluorescein signal is extracted from the observed signal by subtracting a scaled version of the indocyanine green signal. Indocyanine green wash-in time constants were significantly different between patients whose foot ulcers led to amputation relative to those whose foot ulcers healed without surgery (p < 0.10) and between patients with past foot ulcers relative to patients with no history of foot ulcers (p < 0.05). It was determined that while the flow-limited assumption for fluorescein was valid in healthy rat skin, it was not valid in diabetic subjects.","Made available in DSpace on 2015-09-25T22:46:15Z (GMT). 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The fluorescein signal is characterized by a wash-in time constant dependent on both the blood flow and permeability. Under flow-limited conditions the wash-in time constant is inversely proportional to the blood flow only. Significant differences in the fluorescein wash-in time constant were measured between diabetic and non-diabetic subjects (p < 0.10) and between diabetic patients with chronic foot ulcers and those without ulcers (p < 0.01). A new technique, dual dye dermofluorometry, which measures the simultaneous signals from an intravascular tracer, indocyanine green, and a diffusible tracer, sodium fluorescein, was developed. The indocyanine green signal is described by a physiologically-based pharmacokinetic model with a wash-in time constant inversely proportional to the blood flow. The extravascular fluorescein signal is extracted from the observed signal by subtracting a scaled version of the indocyanine green signal. Indocyanine green wash-in time constants were significantly different between patients whose foot ulcers led to amputation relative to those whose foot ulcers healed without surgery (p < 0.10) and between patients with past foot ulcers relative to patients with no history of foot ulcers (p < 0.05). It was determined that while the flow-limited assumption for fluorescein was valid in healthy rat skin, it was not valid in diabetic subjects.","Made available in DSpace on 2015-09-25T22:46:15Z (GMT). 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