The renin-angiotensin system plays a pivotal role in regulating blood pressure and is involved in the pathogenesis of kidney disorders and other diseases. Here, we report that the growth factor midkine is what we believe to be a novel regulator of the renin-angiotensin system. The hypertension induced in mice by 5/6 nephrectomy was accompanied by renal damage and elevated plasma angiotensin II levels and was ameliorated by an angiotensin-converting enzyme (ACE) inhibitor and an angiotensin receptor blocker. Notably, ACE activity in the lung, midkine expression in the lung, and midkine levels in the plasma were all increased after 5/6 nephrectomy. Exposure to midkine protein enhanced ACE expression in primary cultured human lung microvascular endothelial cells. Furthermore, hypertension was not induced and renal damage was less severe in midkine-deficient mice. Supplemental administration of midkine protein to midkine-deficient mice restored ACE expression in the lung and hypertension after 5/6 nephrectomy. Oxidative stress might be involved in midkine expression, since expression of NADH/NADPH oxidase-1, -2, and -4 was induced in the lung after 5/6 nephrectomy. Indeed, the antioxidative reagent tempol reduced midkine expression and plasma angiotensin II levels and consequently ameliorated hypertension. These results suggest that midkine regulates the renin-angiotensin system and mediates the kidney-lung interaction after 5/6 nephrectomy.

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We focused on a cicada wing which has superhydrophobic surface, antireflection to the light, unique tribology, and antibacterial property. From the SEM view, circular truncated cones in nanoscale were widely spread with regularly. It was just like nanopillar array. After the signature pattern was analyzed, we mimicked its structure composed of Si. Si nanostructure was fabricated mainly by wet process to decrease the cost but its dimension was controllable. We reported antibacterial property of the structure. Fabricated Si nanopillar array showed antibacterial property to E. Coli.

Localized surface plasmon resonance (LSPR) attracts attention for the fabrication of a biosensor because it can be used easily and is highly sensitive to the change in surface reflective index. Anodic aluminum oxide (AAO) has self-assembled nanoholes and is fabricated easily all over the Al substrate. The depth and diameter of the nanoholes are easily controlled by changing the etching solution and applied voltage. By depositing a Au thin film on the AAO substrate, the sensitivity of the sensor chip was affected by both optical interference and LSPR. In this study, the optical property of the AAO-based LSPR sensor chip was characterized on the basis of the nanostructure. We presented a biosensing application of the AAO-based LSPR sensor chip. The highest sensitivity of the sensor chip was observed at the AAO nanohole diameter of 75 nm and the AAO nanohole depth of 0.5 µm, when bovine serum albumin (BSA) adsorbed on the sensor chip.