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AimsSTAT3 is a key modulator of activation and differentiation of macrophages. But it is still unknown if deficiency of STAT3 activates macrophages to destroy erythrocytes by phagocytosis. We generated STAT3 conditional knockout mice by crossing floxed STAT3 mice with Tie2 promoter-driven Cre-recombinase transgenic mice and clarified that Stat3 plays a critical role in the formation and activation of macrophages.Main methodsBlood cell count, reticulocyte count, serum lactate dehydrogenase, erythropoietin, iron and ferritin concentration, and life span of the erythrocytes in Tie2 promoter-driven STAT3 conditional knockout mice were analyzed. To explore the erythropoietic function of the mice, we subjected them to brief hemolytic anemia by injecting them intraperitoneally with phenylhydrazine. The fragility of erythrocytes was examined by scanning electron microscopy and osmotic tolerance test.Key findingsThe conditional knockout mice had mild normocytic anemia. They also displayed higher lactate dehydrogenase, ferritin and erythropoietin concentration, higher reticulocyte count, and a shorter lifespan of erythrocytes compared with wild-type controls. These data suggest that destruction of erythrocytes and secondary blood formation were accelerated in the STAT3 conditional knockout mice. It didn't appear due to the fragility of erythrocytes. A few of the conditional knockout mice suddenly developed acute severe anemia, high body temperature and massive splenomegaly, and died within 2weeks after the onset of anemia.SignificanceThis study provided evidence that STAT3 have a critical role in the destruction of erythrocytes by resident macrophages in the spleen.

A novel apparatus for polarization measurement in the soft X-ray region has been designed, constructed, and installed in the evaluation beamline for soft X-ray optical elements (BL-11) at the SR Center of Ritsumeikan University, Shiga, Japan. It allows us to perform conventional reflection and transmission measurements including rocking curve measurement as well as polarimetric and ellipsometric measurements based on the rotating-analyzer method by using six independently movable motorized stages. As a preliminary test of the apparatus, the reflection profile of a Mo/SiO 2 multilayer mirror prepared by an ion beam sputtering technique, which is designed as a reflection polarizer for use of 13.9 nm, has been measured by the apparatus. The result is compared with that by an existing reflectometer, and the azimuth angle dependence of the reflection intensity has been demonstrated. Consequently, it is shown that the apparatus has the capability to perform the rotating-analyzer ellipsometry.

Unsteady forces acting on a square cylinder in oscillating flow with nonzero mean velocity are measured. The oscillating air flows are generated by a unique AC servomotor wind tunnel. The generated velocity histories are almost exact sinusoidal waves. The measured unsteady forces are examined in relation with the Morison equation and the contribution of the inertia term. It is confirmed that the Morison equation is applicable to explain the present experimental results. The fluid force coefficients, including the inertia coefficients, are evaluated for both in-line and transverse forces.

The present study was designed to evaluate the effects of free iron on normal red blood cells (RBCs) and possible mechanisms responsible for the alteration of the RBC rheological properties. Human RBCs (Ht 5%) were incubated for 1 h at 37°C with 0–2 mM FeSO 4 in the presence of ascorbate. Thiobarbituric acid reactive substances assay was employed to estimate lipid peroxidation and polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate to analyze membrane proteins. A cone-plate viscometer, and low-shear and high-shear rheoscopes were used to compare the rheological parameters in Fe 2+ /ascorbate-treated RBCs with those of diamide-treated ones. The incubation of RBCs with free iron caused a dose-dependent increase in lipid peroxidation, enhanced binding of hemoglobin to the cell membrane, diminishing of band 3 content and the concomitant increase in lower molecular weight peptides (approximately 60 and 35 kDa), while the incubation with diamide resulted in spectrin crosslinking. Both diamide and Fe 2+ /ascorbate treatment impaired RBC deformability and aggregation. The suspensions of Fe 2+ -treated RBCs manifested increased viscosity, presumably due to enhanced formation of three-dimensional aggregates. In conclusion, although in both these cases of oxidative stress the ultimate result was the deterioration of membrane structure and functions, the mechanisms of oxidative changes of the RBCs rheological properties were apparently dissimilar.

Thiol-compounds, dithiothreitol (DTT) and N -acetylcysteine (NAC), were examined for their antioxidant effects on Fe 2+ /ascorbate-treated and diamide-treated red blood cells (RBCs). Both of the compounds protected RBCs against diamide-induced spectrin crosslinking; they also prevented loss of deformability and aggregation impairment in diamide-treated cells. Neither DTT nor NAC were effective in suppressing lipid peroxidation induced by Fe 2+ /ascorbate treatment. DTT showed a limited protective effect on iron-mediated band 3 fragmentation and RBC deformability, but it was capable of preventing the decrease of rouleaux formation rate to some extent. NAC exhibited a dose-dependent band 3 protective activity, partially prevented Fe 2+ /ascorbate-induced deformability impairment and the decrease of rouleux formation rate. These findings suggest that thiol compounds are effective in modulating diamide-induced oxidative alterations of RBCs membrane constituents and rheological properties. NAC is more efficacious than DTT in protecting RBCs against iron-mediated oxidative injury, which can be attributed to its potent reductant and radical scavenging abilities.

In an attempt to explore the process of naturally occurring secretory leukoprotease inhibitor (SLPI) fragmentation, the cleavage profile of SLPI, which had been prepared by recombinant techniques, was investigated biochemically. Restricted fragments of SLPI were detected using SDS-PAGE after treatment with human neutrophil elastase (NE) or normal saliva and sequenced at their cleavage sites. Among these restricted fragments, two species of nearly half-length SLPIs that contained the C-terminal domain, (Arg58-Ala107)SLPI and (Arg59-Ala107SLPI, were detected. They were both as active at inhibiting NE as the parent SLPI. These results suggest that functional SLPI derivatives may be generated physiologically in the respiratory tract under inflammatory and healthy conditions.

Effect of 2,3-diphosphoglycerate (2,3-DPG) on the deformability of human erythrocytes was examined with a rheoscope under shear stress of 8-82 dyn/cm2. With increasing 2,3-DPG in erythrocytes (from 5 to 15 mM/l cells) by incubating with inosine and pyruvate in isotonic 50 mM phosphate-buffered saline, erythrocyte deformability under uniform shear stress was remarkably impaired. But reduction of 2,3-DPG (from 5 to 2.2 mM/l cells) did not affect the deformability. In 2,3-DPG-enriched erythrocytes, increased intracellular hemoglobin concentration (MCHC), decreased intracellular pH, and increased contents of ATP and IMP (and ITP) were observed. (1) When the MCHC (i.e., the internal viscosity) was normalized by suspending in hypotonic medium, the deformability of 2,3-DPG-enriched erythrocytes was greatly improved, but still decreased. (2) The change of intracellular pH between 6.5 and 7.5 (as compared adjusting to same MCHC) did not alter the deformability. (3) The changes of purine nucleotides, ATP (0.6-2.1 mM/l cells), IMP (0-0.9 mM/l cells) and ITP (0-0.5 mM/l cells) did not alter the erythrocyte deformability. In conclusion, decreased deformability of erythrocytes induced by augmentation of 2,3-DPG is due mainly to the increased internal viscosity and due partly to the increased membrane viscoelasticity.

Reactivity enhancement was studied using a reaction between a laser excited atomic beam and a molecular beam. This method was applied to lithium isotope separation, in which the excited Li isotopic atom reacts with CHCIF 2 . It is found that the specified lithium isotope is enriched in the reaction product LiF, whereas LiCl has no selectivity.

The addition of cyclodextrins, especially heptakis (2,6- O -dimethyl)β-cyclodextrin (MeβCD), to synthetic medium, such as Stainer-Scholte medium (D.W. Stainer and M.J. Scholte, J. Gen. Microbiol. 63: 211–220) greatly stimulated the production of filamentous hemagglutinin (F-HA) by Bordetella pertussis Tohama phase I under shaking conditions. Purified F-HA from this culturing system was demonstrated immunochemically and morphologically to be identical with that from static culture.

Three-photon ionization spectroscopy was applied in the visible wavelength region using a Nd: YAG laser-pumped dye laser having a line width of 1.1 GHz. It is observed that the ionization peaks are broadened and the isotopic peaks cannot be resolved in the higher power density region.