In vivo determination of diffusive transport parameters in a superfused tissue.

To address the hypothesis that functional changes in tissue transport can be related to structural alterations, we combined mathematical modeling with in vivo experimentation. The model concept includes interstitial diffusion and removal by a distributed microvasculature. Transport of solute and water across the peritoneum is measured via a plastic chamber affixed to the abdominal wall of anesthetized Sprague-Dawley rats.

Correlating structure with solute and water transport in a chronic model of peritoneal inflammation.

To study the process of chronic peritoneal inflammation from sterile solutions, we established an animal model to link structural changes with solute and water transport. Filtered solutions containing 4% N-acetylglucosamine (NAG) or 4% glucose (G) were injected intraperitoneally daily in 200- to 300-g rats and compared with controls (C). After 2 mo, each animal underwent transport studies using a chamber affixed to the parietal peritoneum to determine small-solute and protein mass transfer, osmotic filtration, and hydraulic flow.

The transport barrier in intraperitoneal therapy.

The peritoneal cavity is important in clinical medicine because of its use as a portal of entry for drugs utilized in regional chemotherapy and as a means of dialysis for anephric patients. The barrier between the therapeutic solution in the cavity and the plasma does not correspond to the classic semipermeable membrane but instead is a complex structure of cells, extracellular matrix, and blood microvessels in the surrounding tissue. New research on the nature of the capillary barrier and on the orderly array of extracellular matrix molecules has provided insights into the physiological basis of osmosis and the alterations in transport that result from infusion of large volumes of fluid.