Combined determination of plasma MMP2, MMP9, and TIMP1 improves the non-invasive detection of transitional cell carcinoma of the bladder

BACKGROUND: Matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) play a major role in the maintenance of extracellular matrix homeostasis and are involved in the process of tumour invasion and metastasis in several malignant tumour entities. The goal of this study is to evaluate the diagnostic value of various circulating MMPs and TIMPs in blood plasma for a non-invasive detection of transitional cell carcinoma of the bladder (TCC). METHODS: In this study the concentrations of MMP1, MMP2, MMP3, MMP9, their inhibitors TIMP1, TIMP2, and the MMP1/TIMP1-complex (MTC1) were quantified in blood plasma with the sandwich enzyme-linked immunosorbent assay (ELISA). Blood plasma samples were investigated from 68 patients (non-metastasized, n = 57 and metastasized, n = 11) with TCC of the bladder and from 79 healthy controls. The mROC program was used to calculate the best two- and three- marker combinations. The diagnostic values for all single markers and the marker combinations were estimated both by the overall diagnostic performance index area under the ROC curve (AUC) and the sensitivity and specificity at cutoff limits with the highest diagnostic accuracy and at the 90% and 95% limits of sensitivity and specificity, respectively. RESULTS: The median MMP2 concentration was elevated in blood plasma in all patient groups with TCC in comparison to the controls (p < 0.001). The concentrations of TIMP1, TIMP2, and MTC1 in plasma probes were significantly lower from patients with non-metastasized TCC compared to the controls. MMP2 tested alone reached the highest sensitivity and specificity at 75%, respectively. The sensitivity and specificity increased when tested in combination with MMP9 and TIMP1 (97%, 94%, respectively). The combination of MMP9 and TIMP1 also showed an improved sensitivity (80%) and specificity (99%) than tested alone. CONCLUSION: MMP2 is a statistically significant marker in blood plasma for bladder cancer detection with an increased diagnostic value in combination with MMP9 and TIMP1. This study showed that the highest sensitivities and specificities are not obtained by testing each marker alone. As shown by the best two-marker combination, which includes MMP9 and TIMP1, the optimized combination does not always include the best single markers

Measurements of Secondary Electron Emission Effects in the Hall Thruster Discharge

The dependence of the maximum electron temperature on the discharge voltage is studied for two Hall thruster configurations, in which a collisionless plasma is bounded by channel walls made of materials with different secondary electron emission (SEE) properties. The linear growth of the temperature with the discharge voltage, observed in the channel with a low SEE yield, suggests that SEE is responsible for the electron temperature saturation in the thruster configuration with the channel walls having a higher SEE yield. The fact that the values of the electron temperature at saturation are rather high may indirectly support the recently predicted kinetic regime of the space charge saturation of the near-wall sheath in the thruster discharge. A correlation between the effects of the channel wall material on the electron temperature and the electron cross-field current was also observed

Operation of a Segmented Hall Thruster with Low-sputtering Carbon-velvet Electrodes

Carbon fiber velvet material provides exceptional sputtering resistance properties exceeding those for graphite and carbon composite materials. A 2 kW Hall thruster with segmented electrodes made of this material was operated in the discharge voltage range of 200–700 V. The arcing between the floating velvet electrodes and the plasma was visually observed, especially, during the initial conditioning time, which lasted for about 1 h. The comparison of voltage versus current and plume characteristics of the Hall thruster with and without segmented electrodes indicates that the magnetic insulation of the segmented thruster improves with the discharge voltage at a fixed magnetic field. The observations reported here also extend the regimes wherein the segmented Hall thruster can have a narrower plume than that of the conventional nonsegmented thruster

Вторая фаза исследования по проведению недельного цикла химиотерапии с использованием паклитаксела и карбоплатина у больных с метастатическим раком мочевого пузыря

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Electron-wall interaction in Hall thrusters

Electron-wall interaction effects in Hall thrusters are studied through measurements of the plasma response to variations of the thruster channel width and the discharge voltage. The discharge voltage threshold is shown to separate two thruster regimes. Below this threshold, the electron energy gain is constant in the acceleration region and therefore, secondary electron emission (SEE) from the channel walls is insufficient to enhance electron energy losses at the channel walls. Above this voltage threshold, the maximum electron temperature saturates. This result seemingly agrees with predictions of the temperature saturation, which recent Hall thruster models explain as a transition to space-charge saturated regime of the near-wall sheath. However, in the experiment, the maximum saturation temperature exceeds by almost three times the critical value estimated under the assumption of a Maxwellian electron energy distribution function. The channel narrowing, which should also enhance electron-wall collisions, causes unexpectedly larger changes of the plasma potential distribution than does the increase of the electron temperature with the discharge voltage. An enhanced anomalous crossed-field mobility (near wall or Bohm-type) is suggested by a hydrodynamic model as an explanation to the reduced electric field measured inside a narrow channel. We found, however, no experimental evidence of a coupling between the maximum electron temperature and the location of the accelerating voltage drop, which might have been expected due to the SEE-induced near-wall conductivity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87763/2/057104_1.pd