Analysis of the mineral composition of taro for determination of geographic origin.

The mineral composition of taro ( Colocasia esculenta (L.) Schott) was analyzed to develop a method to distinguish taro produced in Japan and China. The concentrations of 15 elements (Al, Ca, Cl, Mg, Mn, Br, Co, Cr, Cs, Fe, K, Na, Rb, Sc, Zn) were assayed using instrumental neutron activation analysis. The concentrations of NO(3)(-), SO(4)(2-), H(2)PO(4)(-), Cl(-), malate, and oxalate were measured by ion chromatography. The mean concentrations of H(2)PO(4)(-), Co, Cr, and Na significantly differed (P < 0.01) between taro grown in Japan and that grown in China. Discriminant analysis was performed to identify the most efficient combination of elements and compounds to discriminate the taro geographic origin. The highest percentage of correct classification was achieved with a two-variable model including H(2)PO(4)(-) and Co (100% for Japanese, 93.75% for Chinese). Principal component analysis and cluster analysis using all of the assayed elements and compounds were also conducted to determine which elements significantly accounted for the variation of the taro mineral composition. We report on the potential of H(2)PO(4)(-) and Co concentrations to differentiate taro grown in China and Japan and discuss the sources of variability in the taro mineral composition of our samples.

Characterization of a novel thrombotic middle cerebral artery occlusion model in monkeys that exhibits progressive hypoperfusion and robust cortical infarction.

In an attempt to establish a thrombotic middle cerebral artery (MCA) occlusion model using cynomolgus monkeys, we measured the blood flow in the main MCA tract and cerebral cortex, brain damage, and neurological deficits, and compared them with those of mechanical MCA occlusion model. Thrombotic occlusion was induced photochemically by green light application on the MCA following rose bengal treatment; mechanical occlusion was induced by MCA clipping for 3h. Patency of the main MCA tract showed two patterns in the thrombotic model: permanent occlusion or cyclical flow reduction (CFR). Regional cerebral blood flow (rCBF) decreased during occlusion followed by post-ischemic hyperperfusion in the clipping model, whereas rCBF reduction expanded time-dependently in the thrombotic occlusion model. Brain infarction and neurological scores in the thrombotic occlusion model were significantly larger than those in the clipping occlusion model. In histological assessment, microthrombi containing myeloperoxidase- and fibrinogen-positive cells were observed in the cortex following the thrombotic but not clipping occlusion. These results collectively suggest that this thrombotic MCA occlusion model, because it shows impairment of cerebral microcirculation, could provide a vital platform for understanding progressive ischemia as well as for evaluating potential therapeutic drugs.