Taurine concentrations in fetal, neonatal and pregnant rats.

The concentrations of taurine in the fetal and neonatal organs, and the maternal organs, plasma and urine of rats between the 15th day of gestation and the 21st day after birth were determined using an automatic amino acid analyzer. In the fetal liver and brain and in the placenta, the taurine concentration was the highest of all ninhydrin positive compounds. In the fetal liver and placenta, the concentrations of taurine increased significantly with the gestational days. Concentrations of taurine in the brain were much higher in the fetus and neonate than that in the adult. Moreover, the total amount of taurine per fetus increased markedly after the 15th day of gestation, and near term, reached almost the same amount as in the adult rat liver. In contrast to this, a significant decrease was observed in the taurine concentration in the maternal liver and muscle near term. The concentration of taurine in the urine of pregnant rats decreased near term, but in the plasma of pregnant rats the concentration of taurine did not change during pregnancy.</p

Transamination of L-cysteine sulfinate in the growing rat.

The enzyme activities involved in the transamination of L-cysteine sulfinate (L-alanine 3-sulfinic acid), L-aspartate and L-cysteine were examined in fetal, neonatal and maternal rat liver and placenta. In fetal and neonatal rat liver, aminotransferase activity was most active with L-cysteine sulfinate as a substrate and was also active with L-aspartate, while activity with L-cysteine was very low. The activity of transamination of L-cysteine sulfinate in rat liver developed in parallel with that of L-aspartate and L-cysteine. The aminotransferase activity markedly increased after the 19th day of gestation, reaching the same value as adult liver on the 3rd day after birth. The ratios of transamination of L-cysteine sulfinate to that of L-aspartate and to that of L-cysteine were constant during development. These observations suggest that L-cysteine sulfinate, L-aspartate and L-cysteine are transaminated by the same enzyme in the rat liver during development. Since placental aminotransferase activity was extremely low compared with that of the liver, it was suggested that the placenta did not play an important role in the transamination of these amino acids during pregnancy.</p

Effect of taurine concentration on platelet aggregation in gestosis patients with edema, proteinuria and hypertension.

To elucidate the relationship between the high concentration of taurine in platelets and platelet aggregation in patients with EPH gestosis (gestosis with edema, proteinuria and hypertension), platelet aggregation and the platelet release response (release of ATP and beta-thromboglobulin) were studied in the washed platelet suspension (PS) obtained from normal pregnant or non-pregnant women and EPH gestosis patients. Platelet aggregation and platelet release response were significantly lower in EPH gestosis patients than in normal pregnant and non-pregnant women. Platelet aggregation, platelet release response induced by ADP and collagen and the aggregation induced by A23187 were inhibited in taurine-loaded PS from non-pregnant women. These results suggest that the decrease of platelet aggregation in EPH gestosis patients was caused by high concentrations of taurine in platelets, which may inhibit the intracellular Ca2+ movement and platelet release response. Therefore, taurine appears to have a protective effect against the hyper-coagulative state in EPH gestosis.</p

Concentration and uptake of taurine in umbilical blood platelets.

The concentration and uptake of taurine in the umbilical and adult blood platelets were studied. Taurine was the most abundant free amino acid in both umbilical and adult blood platelets. The taurine concentration in umbilical blood platelets (2.30 pmoles/10(4) cells) was significantly lower than that of adult blood platelets (3.27 pmoles/10(4) cells) in contrast to the reverse relationship in taurine concentrations in umbilical and adult blood plasma. No other amino acid showed such significant difference in the concentrations between umbilical and adult blood platelets. Taurine uptake into umbilical blood platelets was temperature sensitive and sodium-dependent in a manner similar to that of adult blood platelets. The uptake conformed well to Hanes-plot. The Vmax of the uptake into adult blood platelets was about 3.6 times higher than that of umbilical blood platelets, but no significant difference was seen in the Km value between the two groups.</p

Platelet taurine concentration and uptake in gestosis patients with edema, proteinuria and hypertension.

The taurine concentration and uptake in platelets obtained from normal pregnant women and gestosis patients with edema, proteinuria and hypertension (EPH gestosis) were investigated. The taurine concentration in platelets showed a marked increase in severe EPH gestosis compared with normal pregnancy or mild and moderate EPH gestosis, while the plasma taurine concentration did not change significantly. Taurine uptake in platelets paralleled the severity of EPH gestosis. The Vmax of the uptake in severe EPH gestosis was about 2.4 times higher than that in normal pregnancy or mild and moderate EPH gestosis, but no significant difference was seen in the Km value among these groups.</p

Effect of intracellular free calcium mobilization on aggregation of umbilical cord blood platelets.

&#60;P&#62;Aggregation activity of platelets in umbilical blood is lower than that in adult blood, but the reason for this is not well understood. It has recently been clarified that calcium plays a role as a second messenger of platelet aggregation, and that glycoproteins of platelet surface membrane such as glycoprotein I b and IIb/IIIa are receptors for agonists inducing aggregation. We examined the concentrations of intracellular calcium and the membrane glycoproteins of platelets in umbilical and adult blood. The increase of intracellular calcium in umbilical platelets was lower than that in adult platelets when the aggregation was induced by ADP, collagen, thrombin and epinephrine. Only calcium ionophore A23187 induced aggregation of both umbilical and adult platelets. On the other hand, there were no qualitative differences between glycoproteins I b and IIb/IIIa of these two groups. Therefore, the low aggregation activity of umbilical platelets seems to be due to low responsiveness of the intracellular calcium system, not to the disorder of functional surface membrane glycoprotein.&#60;/P&#62;</p

High energy electron observation by Polar Patrol Balloon flight in Antarctica

We accomplished a balloon observation of the high-energy cosmic-ray electrons in 10-1000GeV to reveal the origin and the acceleration mechanism. The observation was carried out for 13 days at an average altitude of 35km by the Polar Patrol Balloon (PPB) around Antarctica in January 2004. The detector is an imaging calorimeter composed of scintillating-fiber belts and plastic scintillation counters sandwiched between lead plates. The geometrical factor is about 600cm^2sr, and the total thickness of lead absorber is 9 radiation lengths. The performance of the detector has been confirmed by a test flight at the Sanriku Balloon Center and by an accelerator beam test using the CERN-SPS (Super Proton Synchrotron at CERN). The new telemetry system using the Iridium satellite, the power system supplied by solar panels and the automatic flight level control operated successfully during the flight. We collected 5.7×10^3 events over 100GeV, and selected the electron candidates by a preliminary data analysis of the shower images. We report here an outline of both detector and observation, and the first result of the electron energy spectrum over 100GeV obtained by an electronic counter