To study local capillary permeability to water-soluble substances, we have developed a microscopic tissue clearance method in which a muscle tissue is stained with a test tracer by suffusing its solution around the tissue and the subsequent changes in the tissue concentration due to the tracer washout by capillary flow is recorded. In this method, the subsequent changes in the tissue concentration were measured from the changes of the intensity of the tissue images on the TV monitor. The obtained tissue clearance curve has been theoretically predicted to have a mono-exponential time course and to allow the estimation of local capillary permeability surface area product ( PS ) per unit tissue volume from the time constant of the slope. Then, if the number of perfused capillaries is simultaneously measured in the microscopic field to calculate the capillary surface area per tissue volume, the local permeability coefficient of the tracer can be estimated. This method was applied to the rabbit tenuissimus muscle under maximum vasodilation, using Cr-EDTA ( M. W.=341 ) as the tracer, the obtained clearance curves revealed really mono-exponential time courses as predicted. The calculated values of Cr-EDTA permeability ( 6.00±0.70cm/sec ) well agreed with those reported for sucrose ( M. W.=342 ). It was concluded that this method is useful to measure local capillary permeability of small water-soluble substances. ( J. Jpn. Soc. Biorheol., 2 (3), 127~134, 1988 ).

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Hemorheological changes and complete peripheral blood count before and after flunarizine (FLN) administration (10mg/day for 4 weeks) to the 12 patients with ischemic brain disease were studied to evaluate the mechanism of the therapeutic effects. The characteristics of the patients were 11 complete cerebral infarctions and 1 RIND, 9 males and 3 females, and age (mean ± SD) was 62.3±10.7 years old. The indices were blood passage time of whole blood, 40%HCT RBC suspension and plasma by Nuclepore® filtration method, the blood viscosity by using cone-plate type rotating viscometer (shear rate 18.8-375.0/sec) under the temperature of 37°C. In addition the CBC, fibrinogen, PT, APTT, α _2-PI, AT-III, plasminogen and platelet aggregation test induced by collagen were measured. The obtained results were follows : 1) Whole blood passage time (WBPT) and 40%HCT RBC supension passage time (40%RBC PT) were shortened singnificantly (p<0.05) after FLN administration, although there were no difference in plasma passage time and blood viscosity. 2) Activity of plasminogen decreased singnificantly (p<0.05) after FLN administration. 3) Other indices showed no obvious difference. Shortening of WBPT and 40%RBC PT suggested that FLN caused the increase in the deformability of erythrocytes and would improve the microcirculation of the damaged brain tissue. (J. Jpn. Soc. Biorheol., 2 (3), 135-141, 1988).

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Tension-strain curves of surgical sutures with very small diameters used for ophthalmology, were measured. Materials are eight kinds of surgical suture ; Dexon ( polyglycolic acid : absorbable, synthetic, braided ). Coated Vicryl ( polyglactin 910 : a, s, b ), PDS ( polydioxanone : a, s, monofilament ), Plain gut ( catgut : a, natural, m ). Chromic gut ( catgut : a, n, m ), Silk ( Nonabsorbable, n, b ), Prolene ( polypropylene : N, s, m ), Ethilon ( nylon 66 : N, s, m ). Measurements of tension-strain curve were carried out at 37±0.5°C under a dry condition of 70-80% relative humidity in air and under a wet condition in Ringer's solution, respectively. Dexon showed the maximum breaking strength and Prolene showed the maximum breaking strain in all the sutures under both wet and dry conditions. The breaking strength for all the sutures were lower in the wet condition than in the dry condition. The yield stresses of Dexon and Coated Vicryl were about 31.7g/mm2, that were much less than their breaking stresses. ( J. Jpn. Soc. Biorheol., 2 (3), 142~148, 1988 ).

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