Viscoelastic measurement and differential scanning calorimetry (DSC) were carried out on mucilaginous polysaccharide gels extracted from Gracilariopsis chorda in order to clarify the relation between the gel forming ability and the biochemical structure. The dynamic elastic modulus increased and the DSC endothermic peak accompanying gel-sol transition shifted to higher temperatures with increasing concentration of alkaline pretreatment. This has been attributed to the increase of the content of 3, 6-anhydro-L-galactose by alkaline pretreatment, which leads to the structure ordering. This behaviour is similar to that of agarose, and the gelling mechanism of mucilaginous polysaccharide extracted from Gracilariopsis chorda seems quite different from that of carrageenan.

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We have measured the temperature dependence of the density ρ and the ultrasonic velocity V in the liposome suspension constructed from the total lipids in erythrocyte membrane. ρ and V were measured with an automatic measuring system consisted of a vibrating densimeter and a sequential pulse oscillation velocimeter in the temperature range of 20°C to 52°C. Both ρ and V decreased with raising the temperature θ. Small breaks were observed in the plots of ρ and V against θ at about 30°C and 40°C. The characteristic behavior near 30°C in the total lipids suspension appeared to have a close similarity to those observed in erythrocyte suspension and ghost suspension.

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Turbulent velocity fluctuations were measured and analyzed in the canine ascending aorta using a hot-film anemometer. Blood flow rate and temperature were stabilizid using a special bypass technique. Blood pressure was elevated by Methoxamine infusion in some cases. When whole pooled data were grouped with peak aortic velocity, spectral bandwidth of turbulence, in terms of first and second order characteristic wavenumbers, was found to correlate with systolic aortic pressure in each of these subclassess. In a word, turbulence in the aorta developed when blood pressure was high. These phenomena were thought to be ascribed to stiffening of the aortic wall due to the elevation of systolic blood pressure. Possible relationships between the development of turbulence induced by hypertension and pathophysiological alterations of aorta were discussed.

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In vitro experiments were performed to investigate mechanical properties of relaxed and contracted arterial walls by using cylindrical segments from dog renal arteries. Vasoconstriction was produced by the addition of norepinephrine (NE) to KRS (Krebs-Ringer solution) and by a high K⁺ KRS where K⁺ was substituted for Na⁺ on an equimolar basis. Diameter changes were measured when the transmural pressure was increased from 0 to 180mmHg at a speed of 0.75mmHg/sec. Pressure and diameter (P-D) relationship obtained in the normal KRS (relaxed state) showed a typical J-shaped curve. Activation of vasucular smooth muscle cells by NE and high K⁺ altered this relashionship. NE- and high K⁺- induced contraction produced an N-shaped P-D curve and a linear-type P-D relationship, respectively. From thus obtained P-D curves, we calculated the pressure-strain elastic modulus (E_p=DdP/dD) and the modified stiffness parameter (β”=(D_s/P)/(dD/dP)). We also fitted data to the logistic-type equation including four parameters, D_min, D_max, M and E, which was given as
D=D_min+D_max-D_min/1+Mexp (-P/E)
The observed differences of P-D curves between the relaxed and two contracted states were demonstrated by respective pressure dependences of E_p and β”. The disparities were also attributed to the difference in the magnitude of parameters M and E.

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