Professor

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Address: P.O. Box 245051
Tucson, AZ 85724
Phone: (520) 626-4513
E-Mail: secomb@u.arizona.edu

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Research Interests

The microcirculation is a network of extremely small blood vessels that supplies oxygen and nutrients to all parts of our tissues. The focus of work in our research group is the use of mathematical and computational approaches to study blood flow and mass transport in the microcirculation. Working in collaboration with experimentalists, we aim to understand quantitatively the processes involved. The main areas of our work are:

Mechanics of blood flow in microvessels. We are examining the relationship between red blood cell mechanics and flow resistance in microvessels. Theoretical predictions agree well with observations in glass tubes, but resistance is higher living tissue. We have found that the major cause is the presence of a relatively thick macromolecular lining (endothelial surface layer) on the walls of microvessels.

Mass transport to tissue. We are simulating oxygen exchange between networks of microvessels and surrounding tissues in skeletal muscle and tumors. In skeletal muscle, we have shown how oxygen can be exchanged diffusively between arterioles and capillaries, and we are studying the determinants of maximal oxygen consumption. In tumors, we are studying the relationship between network structure and occurrence of local hypoxic (radiation-resistant) regions. Also, we are analyzing the delivery of chemotherapeutic drugs in tumor tissues.

Structural adaptation of microvascular networks. We are developing models for the stuctural responses of microvessels to functional demands. We have found that maintenance of a stable, functionally adequate distribution of vessel diameters can be achieved if each vessel responds to changes in wall shear stress, intravascular pressure and local metabolic conditions, and if mechanisms exist for information transfer upstream and downstream along flow pathways.

Regulation of blood flow: We are developing models for the active regulation of blood flow by changes in vascular tone, taking into account vascular responses to wall shear stress, pressure and local metabolic state, and including effects of conducted responses along vessel walls.

Selected Publications

Barber JO, Alberding JP, Restrepo JM, Secomb TW. Aug 2008. Simulated Two-dimensional Red Blood Cell Motion, Deformation, and Partitioning in Microvessel Bifurcations. Ann Biomed Eng,2008 Aug 7;

Barber BJ, Donnerstein RL, Secomb TW, Pogreba-Brown K, Steelman R, Ellenby MS, Shen I, Ungerleider RM. Dec 2007. The dicrotic pulse: a common, non-ominous finding after the Ross operation. Pediatr Cardiol, 28:247-9

Styp-Rekowska B, Disassa NM, Reglin B, Ulm L, Kuppe H, Secomb TW, Pries AR. Dec 2007. An imaging spectroscopy approach for measurement of oxygen saturation and hematocrit during intravital microscopy. Microcirculation, 14:207-21

Secomb TW, Styp-Rekowska B, Pries AR. May 2007. Two-dimensional simulation of red blood cell deformation and lateral migration in microvessels. Ann Biomed Eng, 35:755-65