Ultrastructural observation of the elastic fibers in the flow loaded canine carotid arteries was performed by employing a specific elastic fiber stain for electron microscopy. Experiments: Arterio-venous shunt was constructed between the right common carotid artery and the right external jugular vein in six adult beagle dogs. Blood flow rates through the right common carotid artery and the left common carotid artery before anastomosis, after anastomosis and before sacrifice were used for the index of the blood flow loading. After 6 to 8.5 months, these common carotid arteries were observed by transmission electron microscope after staining with tannin acid uranyl acetate and lead citrate. Results : The general structure of the shunted arteries loaded high blood flow was preserved, although they showed slightly larger diameter than the control arteries. The elastic fibers of the media were increased quantitatively in the flow loaded shunted arteries as compared to those in the control arteries. Consideration: Chronic blood flow load would induce increase and growth of the elastic fibers in the media of the canine carotid artery. We consider that these changes would be mostly physiologic occurrence in the course of the adaptive response. (J. Jpn. Soc. Biorheol., 1 (1), 19~26, 1987).

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The effect of enzymatic degradation of fibrinogen and various high molecular weight compounds on the fibrinogen-induced aggregation of human erythrocytes was quantitatively examined by using a rheoscope combined with a television image analyzer and a computer. (i) Fibrinogen of 305 kDa, resulted from the enzymatic removal of a part of the C-terminal region of A a chains, had the same ability of erythrocyte aggregation as native fibrinogen of 340 kDa. (ii) Sialic acids in fibrinogen did not participate in the interaction between fibrinogen and erythrocyte, while those in erythrocyte surface greatly affected the erythrocyte aggregation. (iii) Among fibrinogen degradation products by plasmin, fragments X and Y induced erythrocyte aggregation in slow velocity compared with fibrinogen, while fragments D and E did not induce it. (iv) The fibrinogen-induced erythrocyte aggregation was accelerated by albumin (which itself could not aggregate erythrocytes), but was not affected by the fibrinogen degradation products, dextran of 40 kDa and polyglutamic acids of 20 kDa and 8 kDa. The interaction between fibrinogen (probably at the D domain of fibrinogen ) and erythocyte surface was discussed, and a molecular mechanism for the interaction of fibrinogen and immunoglobulin G with erythrocytes in the presence of albumin was proposed. (J. Jpn. Soc. Biorheol., 1 (1), 27~37, 1987).

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We have measured the ultrasonic velocity V and the density ρ of swine intact erythrocytes and ghosts suspended in a physiological saline solution over the temperature range from 20° to 40°C, by using an automatic measuring system which mainly consists of a vibrating densimeter and a sequential pulse oscillation velocimeter improved from the sing-around method. The behavior of the temperature dependence of V, ρ and the compressibility B=1/ρ V² in the erythrocyte suspension has a close similarity to those in the ghost suspension; near 30°C, the limiting density number [ρ], the limiting velocity number [V] and the limiting compressibility number [B] decreased largely both in the erythrocyte suspension and in the ghost suspension, where [A]=_??_, A is V, ρ or B, and H is the volume fraction of erythrocytes or the dry weight concentration of ghosts. The density and the compressibility of the whole erythrocyte and the ghost membrane are obtained; their temperature dependence is discussed. ( J. Jpn. Soc. Biorheol., 1 (1), 38~45, 1987.)

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