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Biomedical subjects

C G Ellis

Publications and source records attributed to C G Ellis.

59 records · Page 4Linked to original sources
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The Microcirculation Physiome Project.

Presented is a discussion of steps towards the creation of a database of the microcirculation encompassing anatomical and functional experimental data, and conceptual and computational models. The discussion includes issues of database utility, organization, data deposition, and linkage to other databases. The database will span levels from gene to tissue and will serve both research and educational purposes.

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Effect of superoxide dismutase and 21-aminosteroids (lazaroids) on microvascular perfusion following ischemia-reperfusion in skeletal muscle.

Intravital video microscopy was used to test superoxide dismutase and a lazaroid analogue, U-74389F, as a pretreatment for ischemia-reperfusion-induced microvascular dysfunction in skeletal muscle. Twenty-two male Wistar rats (350-400 g), anesthetized with sodium pentobarbital (65 mg/kg i.p.), were divided into groups to test the lazaroid analogue U-74389F (3 mg/kg; n = 8), a citric acid/citrate mixture (CS-4; n = 4) used as the vehicle for the lazaroid analogue, superoxide dismutase (SOD, 10 mg/kg; n = 5), and saline (n = 5). Normothermic ischemia of the extensor digitorum longus muscle was induced for 3 h by tightening a tourniquet placed around the limb above the muscle. Measurements of the number of perfused capillaries (CDper; mm-1) and capillary red blood cell velocity (VRBC; mm/s) were made after 30, 60 and 90 min of reperfusion. Thirty minutes following release of the tourniquet, all test groups showed a significant drop in CDper. The extent of this reduction was maximal in SOD treated muscles, while it was minimized in the lazaroid-treated muscles following 90 min reperfusion. Hyperemia occurred only in muscles treated with saline or lazaroid. The hyperemia was of limited duration in saline-treated muscles, but lasted the entire reperfusion period following lazaroid treatment. An index of microvascular flow, estimated from the product of VRBC and CDper, indicated that flow was significantly greater in muscles treated with lazaroids as compared with all other groups following the 90-min reperfusion. We conclude that whereas SOD was detrimental, the lazaroid analogue U-74389F improved microvascular perfusion following 3 h of no-flow ischemia and 90 min reperfusion.

Animals↗
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Capillary network morphology and capillary flow.

This paper examines the authors' research on capillary network morphology and the heterogeneity of capillary red cell (RBC) perfusion in skeletal muscle with the aim of demonstrating that capillary network structure plays a major role in determining flow distribution. Capillary network morphology was examined by quantifying the heterogeneity of capillary diameters, path and segment lengths, as well as the changes in configuration that occur as vessels accommodate themselves to continual changes of fiber length. Because of the network complexity and the two-phase nature of the perfusing blood, both spatial (i.e. among capillaries) and temporal heterogeneity of capillary perfusion were predicted to result. By means of computer analysis of video images of the microcirculation in vivo, we have demonstrated that more than 70% of the total spatial heterogeneity of capillary RBC perfusion arises from the capillary network as opposed to the arterioles, and that RBC flow continuously redistributes among capillaries. The spatial heterogeneity increases substantially as the arteriolar input to the network falls, and the data predict that during low-flow states, the network will fail to distribute blood properly among its constituent vessels. Thus passive rheological mechanisms and capillary network morphology are important determinants of functional capillary density.

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