PurposeCurcumin (Cur) has been reported to induce apoptosis in human renal carcinoma Caki cells. Dimethoxycurcumin (DMC), one of several synthetic Cur analogues, has been reported to have increased metabolic stability over Cur. We determined whether DMC, like Cur, induces apoptosis in Caki cells and also compared the apoptosis-inducing activity of DMC with that of Cur.Materials and MethodsCaki cells were treated with DMC possessing four methoxy groups, Cur possessing two methoxy groups, or bis-demethoxycurcumin (BMC), which lacks a methoxy group. Cell viability was measured by using a methyltetrazolium assay. Flow cytometry and the caspase-3 activity assay were used to detect apoptosis. The release of cytochrome-c (Cyt c) was detected by Western blot analysis. The production of reactive oxygen species (ROS) was measured by flow cytometry.ResultsDMC, Cur, and BMC reduced cell viability and induced apoptosis, but the potency varied; DMC was the most potent compound, followed by Cur and BMC. ROS production, Cyt c release, and caspase-3 activity were increased, again in the order DMC>Cur>BMC. N-Acetylcysteine, a potent antioxidant, inhibited ROS production, Cyt c release, caspase-3 activation, and apoptosis induction in DMC-treated cells.ConclusionsThese results indicate that DMC, like the original form of Cur, may induce apoptosis in human renal carcinoma Caki cells through the production of ROS, the release of mitochondrial Cyt c, and the subsequent activation of caspase-3. In addition, DMC is more potent than Cur in the ability to induce apoptosis.

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Considering the role of viscosity in the dynamics of physical, chemical, and biological systems, accurate measurement of viscosity is essential. Although many conventional viscometers have been widely used, these conventional viscometers suffer from some drawbacks. In this study, a three-dimensional (3D) printed microfluidic viscometer was proposed based on the estimation of the pressure between two fluids to easily measure viscosity with small samples. The 3D printed microfluidic viscometer can be fabricated through amine-epoxy bonding on 3D printed blocks. By separately delivering samples and reference fluids into two inlets, an interfacial line could be induced. Based on the relation between the pressure ratio and the width of the reference flow, the viscosity (μ) of the sample can be estimated by measuring the relative width of the reference flow. The relation between the pressure and interfacial width between test samples and reference flows in the 3D printed microfluidic viscometers was analyzed by experiment and simulation to determine the effects of the mesh-like pattern of the 3D printed viscometers on the pressure estimation. To validate the proposed method, the viscosity values of glycerol mixtures measured by the 3D printed viscometer were compared with those measured by a conventional viscometer. As an application of the 3D printed viscometer, the viscosity curves for blood samples collected from diabetic and non-diabetic patients depending on their shear rates were compared. As expected, a high blood viscosity in the diabetic group was observed. Based on the experimental demonstrations, the 3D printed viscometer has strong potential to develop portable viscometers that can be translated to commercial outcomes.

In studying blood flow in the vessels, the characteristics of non-Newtonian fluid are important, considering the role of viscosity in rheology. Stenosis, which is an abnormal narrowing of the vessel, has an influence on flow behavior. Therefore, analysis of blood flow in stenosed vessels is essential. However, most of them exist as simulation outcomes. In this study, non-Newtonian fluid was observed in stenosed microchannels under the pulsatile flow condition. A polydimethylsiloxane channel with 60% stenosis was fabricated by combining an optic fiber and a petri dish, resembling a mold. Three types of samples were prepared by changing the concentrations of xanthan gum, which induces a shear thinning effect (phosphate buffered saline (PBS) solution as the Newtonian fluid and two non-Newtonian fluids mimicking normal blood and highly viscous blood analog). The viscosity of the samples was measured using a Y-shaped microfluidic viscometer. Thereafter, velocity profiles were analyzed under the pulsatile flow condition using the micro-particle image velocimetry (PIV) method. For the Newtonian fluid, the streamline was skewed more to the wall of the channel. The velocity profile of the non-Newtonian fluid was generally blunter than that of the Newtonian fluid. A highly oscillating wall shear stress (WSS) during the pulsatile phase may be attributed to such a bluntness of flow under the same wall shear rate condition with the Newtonian fluid. In addition, a highly viscous flow contributes to the variation in the WSS after passing through the stenosed structures. A similar tendency was observed in simulation results. Such a variation in the WSS was associated with plaque instability or rupture and damage of the tissue layer. These results, related to the influence on the damage to the endothelium or stenotic lesion, may help clinicians understand relevant mechanisms.

PurposeWe evaluated the feasibility of a laparoendoscopic single-site (LESS) nephroureterectomy for an upper urinary tract tumor.Materials and MethodsBetween March 2009 and September 2009, 4 patients with upper urinary tract tumors underwent LESS nephroureterectomy. The mean age of the 2 female and 2 male patients was 69 years old, and their mean body mass index was 23.0. We used a homemade single-port device made with a surgical glove and a wound retractor, which were put into a 4 cm periumbilical incision. Operations with articulating and rigid laparoscopic instruments were performed transperitoneally. An open technique with a 4 cm additional midline incision and laparoscopic technique with an endoscopic stapler were used for the treatment of the distal ureter and bladder cuff.ResultsAll cases were completed successfully, without conversion to conventional laparoscopy or open surgery. The mean operative time was 169.5 minutes. The mean estimated blood loss was 361.4 ml. One patient had transfusion and wound infection. The mean hospital stay was 7.8 days. The mean specimen weight and tumor size were 271.8 g and 2.9 cm. Pathologic results of all cases showed urothelial carcinoma with a negative surgical margin. Three patients were in stage T3N0M0 and 1 was in stage T2N0M0.ConclusionsOur initial experience shows that LESS nephroureterectomy with a homemade single-port device is technically feasible. However, long term follow-up for the effect on cancer control and technical development for comfortable surgery are needed.