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Environmental stress increases the risk of electron accumulation in photosystem I (PSI) of chloroplasts, which can cause oxygen (O2) reduction to superoxide radicals and decreased photosynthetic ability. We used three Arabidopsis thaliana lines: wild-type (WT) and the mutants pgr5hope1 and paa1-7/pox1. These lines have different reduced states of iron/sulfur (Fe/S) signals, including Fx, FA/FB, and ferredoxin, the electron carriers at the acceptor side of PSI. In the dark, short-pulse light was repetitively illuminated to the intact leaves of the plants to provide electrons to the acceptor side of PSI. WT and pgr5hope1 plants showed full reductions of Fe/S during short-pulse light and PSI inactivation. In contrast, paa1-7/pox1 showed less reduction of Fe/S and its PSI was not inactivated. Under continuous actinic-light illumination, pgr5hope1 showed no P700 oxidation with higher Fe/S reduction due to the loss of photosynthesis control and PSI inactivation. These results indicate that the accumulation of electrons at the acceptor side of PSI may trigger the production of superoxide radicals. P700 oxidation, responsible for the robustness of photosynthetic organisms, participates in reactive oxygen species suppression by oxidizing the acceptor side of PSI.

Anthracyclines are key drugs for the treatment of children with acute lymphoblastic leukemia (ALL). However, anthracyclines are known to induce QT prolongation, and life-threatening complications, such as torsades de pointe may also occur. To date, there have been no reports on the use of anthracyclines in patients with congenital long QT syndrome (LQTS). We report a child with ALL complicated by congenital LQTS who was treated with anthracyclines. The administration of anthracyclines caused QT-interval prolongation, but this was uneventful with the concomitant administration of magnesium sulfate.

Background: It has been reported that serum KL-6 increases in babies with progressing chronic lung disease (CLD). However, there have been few reports assessing KL-6 in meconium aspiration syndrome (MAS). KL-6 was measured in neonates with respiratory diseases including MAS. Methods: Thirty-eight neonates with respiratory disease were enrolled in the study. These patients were classified into three groups, 14 patients with respiratory distress syndrome (RDS), 14 with MAS, and 10 with transient tachypnea of the newborn (TTN). The control group consisted of 12 healthy neonates. KL-6 levels were measured 1 day (median) after the birth. In the RDS group, measurement was repeated just prior to 36 weeks’ postmenstrual age. Results: The levels of KL-6 were 116 ± 40 U/mL in the RDS, 281 ± 138 U/mL in the MAS, and 106 ± 41 U/mL in the TTN groups. KL-6 levels were significantly higher in the MAS group than in the control group (134 ± 71 U/mL; P