title: Microvessel mean transit time and blood flow velocity of sulfhemoglobin-RBC.
abstract: An indicator dilution technique is described for obtaining time-concentration curves subsequent to bolus injections of sulfhemoglobin red blood cells (SH-RBC), which have a deep greenish-brown color (absorption peak 620 nm vs. 542 and 564 nm for normal red cells). The series- and parallel-coupled microvessels of cat mesentery were studied. This is accomplished by means of video microscopy with a two-window intensity-sensitive video sampler system. The relationship between SH-RBC concentration in blood and optical measurement is linear. Blood flow velocities were calculated from the difference in mean transit times between two points along a vessel. When this technique is used in association with the previously reported method for determining time-concentration curves for the plasma indicator FITC-dextran the mean transit time (t) for red blood cells was less than for plasma in arterioles. The reproducibility of t and flow velocity for both SH-RBC and FITC-dextran from successive injections were reported. The mean transit time ratio of arteriolar SH-RBC to FITC-dextran averages 0.89. Blood flow velocity calculated from SH-RBC is greater than that calculated from FITC-dextran in these same arterioles. The ratio of the velocities averages 1.29.
mesh_terms: D000818:Animals; D002415:Cats; D003911:Dextrans; D004912:Erythrocytes / Q000502:physiology; D007201:Indicator Dilution Techniques; D008643:Mesentery / Q000098:blood supply; D008833:Microcirculation / Q000502:physiology*; D012039:Regional Blood Flow; D013435:Sulfhemoglobin; D013997:Time Factors
chemical_list: D003911:Dextrans; D013435:Sulfhemoglobin