RESUMEN

The effects of reactive oxygen species on cells have attracted great attention from both physiological and pathological aspects. Superoxide (O2-) is the primary reactive oxygen species formed in animals. We previously developed an O2--generating nanodevice consisting of NADPH oxidase 2 (Nox2) and modulated activating factors. However, the device was subsequently found to be unstable in a standard culture medium. Here we improved the device in stability by cross-linking. This new nanodevice, Device II, had a half-life of 3 h at 37 °C in the medium. Device II induced cell death in 80% of HEK293 cells after 24 h of incubation. Superoxide dismutase alone did not diminish the effect of the device, but eliminated the effect when used together with catalase, confirming that the cell death was caused by H2O2 derived from O2-. Flow cytometric analyses revealed that Device II induced caspase-3 activation in HEK293 cells, suggesting that the cell death proceeded largely through apoptosis.

RESUMEN

Our objective was to systematically examine the influence of probe geometry, puncture route, and composition of the abdominal wall on the deviation error with needle display. We made a simplified simulation model of the puncture needle passing to the liver tumor, using a microcomputer system, and visualized the degree of distortion of the puncture needle, changing the thickness and component of the abdominal wall as well as the radius of the probe, site, and angle of puncture. The puncture needle exhibited a displacement error of -10.9 to 3.8 mm (center hole) and -11.3 to 3.8 mm (side attachment). The shift was less accentuated when the radius of the probe was large. The displacement error was less accentuated in the center and accentuated in the left side of the field of view. It is recommended that liver puncture under US guidance be generally performed using a probe with a larger radius through the center hole with the most obtuse puncture angle possible, but when the tumor is localized in the hepatic dome, a more tightly curved probe should be used with an acute angle. We must consider a possible large error in display of the puncture needle during liver puncture and try to prevent hazardous complications.

Asunto(s)

Simulación por Computador , Neoplasias Hepáticas/diagnóstico por imagen , Punciones , Pared Abdominal , Humanos , Microcomputadores , Modelos Biológicos , Agujas , Ultrasonografía

RESUMEN

The authors designed microcomputer simulation models to investigate the combined effect of a distorted grayscale ultrasound image and an inaccurately measured Doppler angle on the accuracy of measurement of blood-flow velocity in vessels located behind mass lesions in the liver. Error decreased when flow was measured at the midpoint of the posttumoral segment of the vessel and increased with distance between the mass and the vessel, with inclination of the vessel, and with decrease in the diameter of the mass. Error was least with the sector probe, intermediate with the convex probe, and greatest with the linear probe. These findings suggest that the error can be minimized when measuring blood flow velocity in a vessel located behind a mass, if the Doppler images are acquired using a sector probe from the midpoint of the posttumoral segment of the vessel.