ATP6AP2 is robustly expressed in pancreatic ß cells and neuroendocrine tumors, and plays a role in maintaining cellular viability.

ATP6AP2, also known as (pro)renin receptor, has been shown to be expressed in several tissues including pancreatic ß cells. Whereas ATP6AP2 plays an important role in regulating insulin secretion in mouse pancreatic ß cells, the expression profiles and roles of ATP6AP2 in human pancreatic endocrine cells and neuroendocrine tumor cells remain unclear. Here in this study, we investigated the expression profiles of ATP6AP2 in pancreatic endocrine cells, and found that ATP6AP2 is robustly expressed in pancreatic insulinoma cells as well as in normal ß cells. Although ATP6AP2 was also expressed in low-grade neuroendocrine tumors, it was not or faintly detected in intermediate- and high-grade neuroendocrine tumors. Knockdown experiments of the Atp6ap2 gene in rat insulinoma-derived INS-1 cells demonstrated decreased cell viability accompanied by a significant increase in apoptotic cells. Taken together, these findings suggest that ATP6AP2 plays a role in maintaining cellular homeostasis in insulinoma cells, which could lead to possible therapeutic approaches for endocrine tumors.

Apoptosis-inducing action of two products from oxidation of sesamol, an antioxidative constituent of sesame oil: a possible cytotoxicity of oxidized antioxidant.

Many effects of sesamol, an antioxidative constituent of sesame oil, have been reported for human health benefits due to its antioxidative action. However, we recently isolated two cytotoxic products, trimer and tetramer of sesamol, from oxidation of sesamol by an assay-guided purification. In this study, we have revealed some cytotoxic characteristics of these products in rat thymocytes and human leukemia K562 cells. Incubation of cells with trimer or tetramer at 10-30 microM for 24h significantly increased cell lethality and population of rat thymocytes containing hypodiploid DNA, suggesting cell death with DNA fragmentation, while it was not the case for 30 microM sesamol. The cytotoxic action of tetramer was more potent than that of trimer in rat thymocytes when their concentrations were 10-30 microM. The incubation of cells with 10 microM tetramer for 24h increased the population of cells with exposed phosphatidylserine, the activity of caspases, and the nick of DNA. These results indicate tetramer-induced apoptosis. In K562 cells, the incubation with tetramer at 10 microM for 72 h significantly inhibited the growth without affecting the lethality. However, tetramer at 30 microM significantly increased cell lethality. It is likely that tetramer exerts more cytotoxic action on normal non-proliferative cells (rat thymocytes) rather than proliferative cancer cells (human leukemia K562 cells). It may be necessary to consider the condition for preservation of sesamol and the safety of products from in vivo oxidation of sesamol for human health.

[Multiple difficulties for central venous access required the distal femoral vein catheterization: a case report].

The low femoral approach for catheterization of the central venous line is a difficult procedure because the surface landmark technique is not helpful. We report a case of patient who required the distal femoral cannulation. Re-catheter cannulation was planned for the patient after the major cardiovascular surgery. The right internal jugular vein showed the venous thrombus attributed to the previous catheter placement for the operation. The left internal, jugular vein had anatomical anomaly at the level of cricoid cartilage and the last approach for cannulation was not feasible. The right subclavian and right femoral regions were scarred with the surgical procedure. Finally, we performed the distal femoral cannulation using real time ultrasound guidance. When multiple difficulties for venous access are present, ultrasound-guided low approach of femoral vein might be one of the solutions.