ABSTRACT. Deformability of red blood cells (RBC) is an important determinant of microcirculation, of oxygen transport and release to the tissues, and of RBC life span. Deformability of RBC from five fetuses, 20 preterm infants, 20 term neonates, and 20 adults was determined by direct microscopic observation of RBC subjected to shear stresses of 6 to 85 dyn/cm2 using a counter-rotating rheoscope. There was no significant difference in deformability among RBC from the fetuses, the preterm and term neonates, and the adults at any shear stress. More than 95% of fetal, neonatal, and adult RBC were capable of tanktread motion. Compared to adults, the frequency distribution of RBC deformability was slightly broader in the fetuses and neonates because of the presence of more highly and poorly deformable RBC. The increased number of rigid RBC may contribute to the shortened life span of fetal RBC. (Pediatr Res 20:93-96, 1986) Abbreviation RBC, red blood cell Studies on the deformability of RBC from full-term neonates gave conflicting results: neonatal and adult RBC show no difference in deformability when studied under defined shear forces by a rheoscope (10) or an ektacytometer (1 1). However, RBC from term neonates require higher suction pressures for complete aspiration into narrow micropipettes (12) and are less filterable (1 3-16) than adult RBC.Little is known about the deformability of RBC from preterm infants. Buchan (15) studied filterability of RBC from preterm infants with gestational age of 34 to 37 wk and measured lower filtration rates in preterm infants compared to term neonates. Coulombel et al.(1 1) used an ektacytometer to determine deformability of RBC from 1 I neonates with 35 to 40 wk of gestational age. They did not find a correlation between RBC deformability and gestational age. Studies on the deformability of RBC from fetuses and small preterm infants do not appear to exist in the literature.In the present study, deformability of RBC from fetuses with 18 to 20 wk and from preterm and term neonates with 24 to 4 1 wk of gestational age were measured by means of a rheoscope. Our results indicate no significant difference in deformability between RBC from fetuses, preterm infants, term neonates, and adults.For the premature infant, maintenance of an adequate tissue MATERIALS AND METHODS oxygen supply is a major problem. Oxygen transport to the tissues is dependent on effective blood flow and on rapid oxygenThe deformability measurements were performed on blood release from the RBC. Both effective blood flow and the rate of samples from five fetuses (18-20 wk of gestation), 20 preterm oxygen uptake are influenced by the ability of RBC to deform infants, 20 term neonates, and 20 adults. The study was approved (i.e. to assume new shapes) (1-3). RBC deformability is essential by the Department of Pediatrics Human Subjects Research Comat four levels: 1) adaptation to higher shear forces in large vessels mittee. Informed consent was obtained from the mothers of the with rapid flow, thereby lowering bloo...

1.5 p1 of unfractionated and density-separated red blood cells (RBC) of healthy adult donors were suspended in Dextran-70 buffer solutions (32cP) at different pH-values (range: 6.9 to 8.0) and osmolalities (range: 200 to 600 mmollkg). The RBC elongations were measured by a Rheoscope at different shear stresses and evaluated semiautomatically. Results: 1. Acidosis did not impair RBC deformability in any of the fractions. 2. Alcalosis caused a slight decrease in the deformability of non-fractioned RBC, whereas the deformability of aged RBC fell markedly. The young RBC remained uneffected. 3. Hyposmolality moderately increased the deformability of young cells. This increase in deformability was more pronounced for non-fractionated and aged RBC. 4. Hyperosmolality significantly reduced RBC deformability, especial19 in the non-fractionated and aged RBC population. We conclude that young RBC withstand severe alcalosis or hyper-osmolality better than aged RBC. Red blood c e l l (RBC) aggregation induced by f i b r i n o g e n i s a major determinant o f t h e non-Newtonian f l o w behavior o f blood and has been suggested as a p o s s i b l e c o n t r i b u t i n g f a c t o r f o r disturbed microcircu-l a t o r y f l o w and thrombogenesis. The purpose o f the present i n v e s t i g at i o n was t o evaluate several experimental measures o f RBC aggregation i n order t o determine t h e i r a b i l i t y t o d i f f e r e n t i a t e between groups w i t h low (25 neonates), normal (35 a d u l t c o n t r o l s) , and h i g h (59 pregnant women, 24 n e p h r o t i c syndrome) f i b r i n o g e n l e v e l s. The f o l l o w-i n g aggregation measures were employed: 1) Microscopic Aggregation Index (MAI); 2) Zeta Sedimentation R a t i o (ZSR); 3) Aggregation H a l f Time (AHT) a f t e r cessation o f shear; 4) R e l a t i v e L i g h t Transmission (RLT) a f t e r 1 and l o minutes o f s t a s i s ; 5) shear r a t e a t Minimum L i g h t Transmission (MLT) ; 5) Myrenne Erythrocyte Aggregation(MEA) .

Ein Beitrag zum Requiem-Essay von Hartmut Krones (ÖMZ 1987/1) Über kein Werk Mozarts wurde mehr Tinte vergossen als über sein Requiem, konstatierte bereits Alfred Einstein. Ebenso wie Hartmut Krones' Untersuchung von Gossecs "Messe des Morts" als einem seiner stilistischen Vorläufer und Vorbilder dürften (noch weithin ausstehende) Studien über die Referenzwerke von Gassmann, Reutter, M. Haydn, Bonno und Cimarosa gleichermaßen Einsteins Erkenntnis bestätigen, Mozart habe "viel mehr gehört und angenommen und abgestoßen, als wir wissen; seine Seele war im Anhören zu aktiv, lebendig, schöpferisch, als daß ihre Formung sich auch nur halbwegs nachrechnen ließe". Die Forderung nach unverwechselbarer schöpferischer Originalität wurde erst zu Beginn des 19. Jahrhunderts erhoben, so daß bis dahin auch das Kirchenmusik-Vokabular als eine gleichsam "etablierte" Errungenschaft, die es zu erhalten galt, frei verfügbar stand. Daher bildet nicht nur Mozarts Requiem einen Brennpunkt verschiedenster Einflüsse, vielmehr erwuchsen seine Vorläufer in gleicher Weise dem Bestand der großen kirchenmusikalischen Traditionen. Einige Beispiele mögen zur Veranschaulichung beitragen: