In the present study, we investigated the antioxidative effect of oolong tea in vitro and in vivo using the oxygen radical absorbance capacity (ORAC) assay. An oolong tea extract, catechin and related compounds suppressed the oxidation of fluorescence induced by AAPH in a dose-dependent manner, that is, they prolonged the antioxidant time in vitro. Oral administration of the oolong tea extract to mice treated with restraint stress increased ORAC activity in plasma as compared with a stress control group. The extract also increased plasma vitamin C levels, and there was a good relationship between ORAC activity and the vitamin C level in plasma. The elevation of plasma ORAC and vitamin C level may have been related to the stress-relieving effect of oolong tea. These effects are probably due to the antioxidative properties of the tea. Thus, these findings suggested that oolong tea has beneficial effects on health related to its antioxidative action.

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This study examined the hypoglycaemic activity of Cyclocarya paliurus (Batal.) Iljinskaja (C. paliurus) in ICR mice by oral glucose tolerance testing. The blood glucose level was significantly lower in the C. paliurus extract treatment group than in the control group after animals were given sucrose. This difference was not observed following the administration of glucose. We demonstrated that the chronological change in the level of blood glucose in genetically hyperglycemic obese KK-Ay mice is significantly lower when C. paliurus extract is administered daily for three weeks. An in vitro study showed that C. paliurus inhibits alpha-glucosidase, a disaccharide-degrading enzyme in the small intestinal mucosa, leading to a decrease in the absorption of glucose into the blood and a subsequent lowering of the blood glucose level.

Three kinds of surface-coil-type resonators (SCRs) operating at 720 MHz were fabricated for in vivo temporal electron spin resonance (ESR) measurements. The inner diameter of the singleturn coil of the SCRs was 3, 4, or 10 mm. Resonator Q increases and the detection limit decreases with coil diameter. The distance across which the microwave magnetic field can penetrate in the direction facing to the coil was about the same (about 2 mm) for all SCRs. In vivo kinetic studies of intravenously injected 4-hydroxy-2,2,6,6-tetramethylpiperidin-l-oxyl (TEMPOL) were performed at the liver, kidney, stomach, rectum, vein, and skin of rats with SCRs suited to the target areas. The halflife of TEMPOL was estimated from the exponential decay of the ESR signal intensity (the peak-topeak height). Different sites in the rat showed apparent differences in the half-life of TEMPOL. This suggests that the apparent differences in the reducing ability of TEMPOL are related to the organ or tissue where measurement is taken because no excretion of TEMPOL was observed.

bThe substitution of glutamic acid (E) for lysine (K) at position 627 of the PB2 protein of avian H5N1 viruses has been identified as a virulence and host range determinant for infection of mammals. Here, we report that the E-to-K host-adaptive mutation in the PB2 gene appeared from day 4 and 5 along the respiratory tracts of mice and was complete by day 6 postinoculation. This mutation correlated with efficient replication of the virus in mice.