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erythrocyte deformability of nonpregnant, pregnant, and fetalblood
Vol. 33, No. 1
18th Meeting of theJapanese Society of Biorheology
91
ERYTHROCYTE DEFORMABILITY OF NONPREGNANT,PREGNANT,AND FETAL BLOOD T.Sawai,K.Eguchi,Y.Mizutani,T.Kudo,S.Noji Department of Obstetrics and Gynecology, Okayama University Medical School, Okayama, Japan Erythrocyte deformability is an important determinant of microcirculation, of oxygen transport and release to the tissue. In an attempt to clarify the theological peculiarity during pregnancy, erythrocyte deformability was measured in 10 nonpregnant controls and 10 pairs of mothers and newborns. When the hematocrit of the erythrocyte suspension in dextran solution was adjusted to 35%, the deformability of fetal erythrocytes was significantly higher than maternal blood (Pc 0.05), and it was almost similar to that of nonpregnant controls. Erythrocyte deformability was dependent on the hematocrit, and there was an optimal hematocrit value at which the deformability was maximal. The hematocrit, where the deformability was maximal, was a lower value (32-35%) in maternal blood, conversely, a higher value(47- 50%) in cord blood than that (40-43%) in the nonpregnant. Despite decreased deformability of maternal erythrocytes, it may be compensated by reducing the hematocrit (hemodilution), preserving effective peripheral circulation including uteroplacental perfusion. On the other hand, the deformability of fetal erythrocytes may be higher in vivo at the hematocrit of 4750% to supply oxygen to the fetal tissue even in a low oxygen condition.
EVALUATION OF EFFECTIVE PORE RADIUS OF NICKEL MESH BY PRESSURE-FLOW RATE RELATIONSHIPS OF AIRFLOW N. Uyesaka, S.Yamawaki', T. Oonishi 2, T. Kawa', H. Shio ~, T. Fujino" Dept. of Physiol., Nippon Med. Sch., Tokyo, 'Tsukasa Sokken CO., LTD., Tokyo, 2The Med. Inform. Inst., The Kanto Teishin Hosp., Tokyo, ~The Shiga Med. Cent. for Adult Diseases, Shiga, 'Dept. of 1st Int. Med., Kyusyu Univ., Fukuoka, Japan A porous thin metal filter, nickel mesh, has been found to be useful in investigating red cell deformability, both physiologically and clinically (e.g. Biorheology 29, 217-229, 1992; N. Engl. J. Med. 328, 73-80, 1993; Blood Cells 20, 151-165, 1994; Am. J. Hematol. 48, 19-28, 1995). However, it remains a problem relating to batch standardization to be settled. Therefore, we have developed a simple quantitative technique for measuring the effective pore radius of the filter by means of the pressure-flow rate relationships of airflow. We measured flow rate and pressure difference between pore entrance and exit of the filter, using a precision differential pressure transducer (PZ-77, Tsukasa Sokken, Tokyo, JPN) and a high performance flowmeter (LFC-1, Tsukasa Sokken, Tokyo, JPN) which is also composed of the differential pressure transducer. Errors of the transducer are in the range of 0.1% of full scale, which is autholized by the Ministry of International Trade and Industory of Japan. In our experimental conditions, Reynolds number was below 10. Accordingly, we determined the effective pore radius (d) of the filter based on Hagen-poiseuille equation. Flow rate of a saline solution obtained by the vertical-tube method (e.g. Blood Cells 20, 151-165, 1994) showed a linear relationship with d4(y=7.18x+.21, r=.98, p--.0001). Unlike a microscopic observation, the evaluation of pore radius by airflow was very reproducible and quantitative; the deflection of pore diameter can be determined to an accuracy of the order of 0.01~tm because of the accuracy of the transducer used. Thus, we conclude that this method is useful in characterizing filters with narrow pores and could be of value in various related fields of hemorheology.
18th Meeting of theJapanese Society of Biorheology
91
ERYTHROCYTE DEFORMABILITY OF NONPREGNANT,PREGNANT,AND FETAL BLOOD T.Sawai,K.Eguchi,Y.Mizutani,T.Kudo,S.Noji Department of Obstetrics and Gynecology, Okayama University Medical School, Okayama, Japan Erythrocyte deformability is an important determinant of microcirculation, of oxygen transport and release to the tissue. In an attempt to clarify the theological peculiarity during pregnancy, erythrocyte deformability was measured in 10 nonpregnant controls and 10 pairs of mothers and newborns. When the hematocrit of the erythrocyte suspension in dextran solution was adjusted to 35%, the deformability of fetal erythrocytes was significantly higher than maternal blood (Pc 0.05), and it was almost similar to that of nonpregnant controls. Erythrocyte deformability was dependent on the hematocrit, and there was an optimal hematocrit value at which the deformability was maximal. The hematocrit, where the deformability was maximal, was a lower value (32-35%) in maternal blood, conversely, a higher value(47- 50%) in cord blood than that (40-43%) in the nonpregnant. Despite decreased deformability of maternal erythrocytes, it may be compensated by reducing the hematocrit (hemodilution), preserving effective peripheral circulation including uteroplacental perfusion. On the other hand, the deformability of fetal erythrocytes may be higher in vivo at the hematocrit of 4750% to supply oxygen to the fetal tissue even in a low oxygen condition.
EVALUATION OF EFFECTIVE PORE RADIUS OF NICKEL MESH BY PRESSURE-FLOW RATE RELATIONSHIPS OF AIRFLOW N. Uyesaka, S.Yamawaki', T. Oonishi 2, T. Kawa', H. Shio ~, T. Fujino" Dept. of Physiol., Nippon Med. Sch., Tokyo, 'Tsukasa Sokken CO., LTD., Tokyo, 2The Med. Inform. Inst., The Kanto Teishin Hosp., Tokyo, ~The Shiga Med. Cent. for Adult Diseases, Shiga, 'Dept. of 1st Int. Med., Kyusyu Univ., Fukuoka, Japan A porous thin metal filter, nickel mesh, has been found to be useful in investigating red cell deformability, both physiologically and clinically (e.g. Biorheology 29, 217-229, 1992; N. Engl. J. Med. 328, 73-80, 1993; Blood Cells 20, 151-165, 1994; Am. J. Hematol. 48, 19-28, 1995). However, it remains a problem relating to batch standardization to be settled. Therefore, we have developed a simple quantitative technique for measuring the effective pore radius of the filter by means of the pressure-flow rate relationships of airflow. We measured flow rate and pressure difference between pore entrance and exit of the filter, using a precision differential pressure transducer (PZ-77, Tsukasa Sokken, Tokyo, JPN) and a high performance flowmeter (LFC-1, Tsukasa Sokken, Tokyo, JPN) which is also composed of the differential pressure transducer. Errors of the transducer are in the range of 0.1% of full scale, which is autholized by the Ministry of International Trade and Industory of Japan. In our experimental conditions, Reynolds number was below 10. Accordingly, we determined the effective pore radius (d) of the filter based on Hagen-poiseuille equation. Flow rate of a saline solution obtained by the vertical-tube method (e.g. Blood Cells 20, 151-165, 1994) showed a linear relationship with d4(y=7.18x+.21, r=.98, p--.0001). Unlike a microscopic observation, the evaluation of pore radius by airflow was very reproducible and quantitative; the deflection of pore diameter can be determined to an accuracy of the order of 0.01~tm because of the accuracy of the transducer used. Thus, we conclude that this method is useful in characterizing filters with narrow pores and could be of value in various related fields of hemorheology.