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Components of the activated complement cascade are considered to play a pivotal role in ischemia-reperfusion-induced organ injury. With the use of intravital epifluorescence microscopy, we investigated the effect of complement inhibition by the recombinant soluble complement receptor 1 (sCR1; TP10) on the effect of macromolecular microvascular permeability, functional capillary perfusion, and leukocyte endothelium interaction in postischemic pancreatitis. Anaesthetized Sprague-Dawley rats were subjected to 60 min of normothermic pancreatic ischemia induced by micro-clipping of the blood-supplying arteries of the organ. Rats who received sCR1 (15 mg/kg body wt iv; n = 7) during reperfusion showed a significant reduction of permeability (1.77 [+ or -] 1.34 x [10.sup.-8] cm/s; n = 7) of tetramethylrhodamine isothiocyanate-labeled albumin injected 90 min after the onset of reperfusion compared with vehicle-treated animals (6.95 [+ or -] 1.56 x [10.sup.-8] cm/s; n = 7). At 120 min after the onset of reperfusion, the length of red blood cell-perfused capillaries (functional capillary density) was significantly improved (from 279 [+ or -] 15.7 to 330 [+ or -] 3.7 [cm.sup.-1]; n = 7) and the number of leukocytes adherent to postcapillary venules was significantly reduced (from 314 [+ or -] 87 to 163 [+ or -] 71 [mm.sup.-2]; n = 7) by sCR1 compared with vehicle treatment. Complement inhibition by sCR1 effectively ameliorates pancreatic ischemia-reperfusion-induced microcirculatory disturbances and might be considered for treatment of postischemic pancreatitis. permeability; ischemia; reperfusion; acute pancreatitis; transplantation

Orthogonal polarization spectral (OPS) imaging is a new technique that can be used to visualize the microcirculation with reflected light. It uses hemoglobin absorption to visualize the red blood cells (RBCs). Thus the method could fail at low hematocrit (Hct). The aim of this study was to validate OPS imaging for quantitative measurements of diameter and functional capillary density (FCD) under conditions of hemodilution of varying degrees to achieve a wide range of Hcts. The validation was performed in the dorsal skinfold chamber of nine awake Syrian golden hamsters. Measurements of vessel diameter and FCD were performed off-line using Cap-Image on video sequences captured using OPS imaging and standard intravital fluorescence microscopy at baseline, 85, 70, 55, and 40% of the initial Hct. For hemodilution, isovolumic exchange of blood for 6% Dextran 60 was performed. Bland-Altman plots for the vessel diameter and FCD show good agreement between the two methods for both parameters at all studied Hcts. As expected, there was a systematic bias of ~4 [micro]m in the diameter measurements since the RBC column was measured and not the intravascular diameter. In conclusion, OPS imaging can be used to measure diameter and FCD at a wide range of Hcts. Cytoscan; orthogonal polarization spectral imaging

A substantial loss of fluorescent-labeled microspheres (FM) is often a problem in the utilization of FM for measuring regional blood flow. A filtration device was designed that permits the tissue sample to remain in a single container throughout the process to make it easier and to prevent the loss of FM. The main part of the sample-processing unit is a single-tube filtration device with a polyamide wire mesh.

The role of leukocyte plugging and edema in skeletal muscle ischemia-reperfusion injury was examined to observe the effects of interstitial edema and leukocyte-capillary plugging. Results of the experiment revealed that phalloidin treatment preserved the endothelial barrier, improved functional capillary density and reduced the amount of PI measured. Furthermore, macromolecular leakage plays an essential role in tissue injury.

Intravital microscopy was utilized to determine the effects of dextran in rabbit striated muscles during ischemia-reperfusion injury. Administration of dextran reduced postischemic leukocyte rolling and leukocyte adherence by preventing the reduction in functional capillary density in rabbit striated muscles during ischemia-reperfusion. Furthermore, the effects of dextran were mediated by steric interference of large polysaccharide molecules with the different binding sites involved in leukocyte rolling and adherence.

The effects of varying duration of ischemia in hamster striated skeletal muscles were analyzed to determine the various stages of ischemia-reperfusion injury. One to two hours of ischemia produced negligible damage in microvascular function and increased venule diameter and rolling fraction. Furthermore, ischemia stimulated leukocyte activity by increasing the number of adherent leukocytes and reductions in capillary perfusion.