PURPOSE: This study was conducted to determine the influence of standoff material on acoustic radiation force impulse (ARFI) measurements in an elasticity phantom by using two different probes. METHODS: Using ARFI elastography, 10 observers measured the shear wave velocity (SWV, m/sec) in different lesions of an elasticity phantom with a convex 4C1 probe and a linear 9L4 probe. The experimental setup was expanded by the use of an interposed piece of porcine muscle as standoff material. The probe pressure on the phantom was registered. RESULTS: Faulty ARFI measurements occurred more often when quantifying the hardest lesion (74.0 kPa 4.97 m/sec) by the 9L4 probe with the porcine muscle as a standoff material interposed between the probe and the phantom. The success rate for ARFI measurements in these series was 52.4%, compared with 99.5% in the other series. The SWV values measured with the 9L4 probe were significantly higher (3.33±1.39 m/sec vs. 2.60±0.74 m/sec, P < 0.001 in the group without muscle) and were closer to the reference value than those measured with the 4C1 probe (0.25±0.23 m/sec vs. 0.85±1.21 m/sec, P < 0.001 in the same group). The SWV values measured when using the muscle as a standoff material were lower than those without the muscle (significant for 9L4, P=0.040). The deviation from the reference value and the variance increased significantly with the 9L4 probe if the muscle was in situ (B=0.27, P=0.004 and B=0.32, P < 0.001). In our study, the pressure exerted by the operator had no effect on the SWV values. CONCLUSION: The presence of porcine muscle acting as a standoff material influenced the occurrence of failed measurements as well as the variance and the accuracy of the measured values. The linear high-frequency probe was particularly affected.
Acoustics* ; Elasticity ; Elasticity Imaging Techniques* ; Muscles ; Reference Values ; Transducers ; Ultrasonography

PURPOSE: The purpose of this study was to compare the reliability of ultrasound-based shear wave elastography in regions of homogeneous versus heterogeneous elasticity by using two different probes. METHODS: Using acoustic radiation force impulse (ARFI) elastography, we measured the shear wave velocity (SWV) in different lesions of an elastography phantom with the convex 4C1 probe and the linear 9L4 probe. The region of interest (ROI) was positioned in such a way that it was partly filled by one of the lesions (0%, 25%, 50%, 75%, and 100%) and partly by the background of the phantom (100%, 75%, 50%, 25%, and 0%, respectively). RESULTS: The success rate was 98.5%. The measured value and the reference value of SWV correlated significantly (r=0.89, P<0.001). Further, a comparison of the two probes revealed that there was no statistical difference in either the mean or the variance values. However, the deviation of SWV from the reference was higher in the case of the 9L4 probe than in the case of the 4C1 probe, both overall and in measurements in which the ROI contained structures of different elasticity (P=0.021 and P=0.002). Taking into account all data, for both probes, we found that there was a greater spread and deviation of the SWV from the reference value when the ROI was positioned in structures having different elastic properties (standard deviation, 0.02±0.01 m/sec vs. 0.04±0.04 m/sec; P=0.010; deviation from the reference value, 0.21±0.12 m/sec vs. 0.38±0.27 m/sec; P=0.050). CONCLUSION: Quantitative ARFI elastography was achievable in structures of different elasticity; however, the validity and the reliability of the SWV measurements decreased in comparison to those of the measurements performed in structures of homogeneous elasticity. Therefore, a convex probe is preferred for examining heterogeneous structures.
Acoustics* ; Elasticity Imaging Techniques ; Elasticity* ; Phantoms, Imaging ; Population Characteristics ; Reference Values ; Transducers ; Ultrasonography

BACKGROUNDIncreased levels of plasma lipopolysaccharide (LPS) have been found in obesity and diabetes patients. This study was to investigate the effect of LPS on pancreatic beta-cell viability and the involvement of caspase 3 in NIT-1 cell line.

METHODSMouse insulinoma NIT-1 cells were treated with LPS for the indicated time and dose. Cell viability was measured by cell counting kit-8 reagent. Toll-like receptor 4 (TLR4), caspase 3 and cleaved caspase 3 were detected by Western blotting. Insulin was determined by radioimmunoassay (RIA).

RESULTSLPS promoted NIT-1 cell proliferation at 1 µg/ml, peaked at 72 hours of incubation. A reduction in cleavage of caspase 3 was observed upon LPS treatment. Bay11-7082, a specific inhibitor of nuclear factor (NF)-κB, blunted LPS-induced inhibition of caspase 3 cleavage. Reduction in chronic insulin secretion was observed after treatment with LPS at 1 µg/ml for 48 and 72 hours, not for 24 hours. TLR4 protein was upregulated when NIT-1 cells were treated with LPS at 1 µg/ml for 24 hours.

CONCLUSIONSLPS promotes early NIT-1 cell proliferation in association with NF-κB-mediated inhibition of caspase 3 cleavage. LPS exerts a time-dependent inhibitory effect on chronic insulin secretion from NIT-1 cells.

Animals ; Caspase 3 ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Insulin ; secretion ; Insulinoma ; metabolism ; Lipopolysaccharides ; pharmacology ; Mice ; NF-kappa B ; metabolism ; Toll-Like Receptor 4 ; metabolism

BACKGROUNDIncreased risk of bladder cancer has been reported in diabetic patients. This study was to investigate the roles of mitogen-activated protein kinase kinase (MEK) 1 and 2 in the regulation of human insulin- and insulin glargine-induced proliferation of human bladder cancer T24 cells.

METHODSIn the absence or presence of a selective inhibitor for MEK1 (PD98059) or a specific siRNA for MEK2 (siMEK2), with or without addition of insulin or glargine, T24 cell proliferation was evaluated by cell counting kit (CCK)-8 assay. Protein expression of MEK2, phosphorylation of ERK1/2 and Akt was analyzed by Western blotting.

RESULTST24 cell proliferation was promoted by PD98059 at 5 - 20 µmol/L, inhibited by siMEK2 at 25 - 100 nmol/L. PD98059 and siMEK2 remarkably reduced phosphorylated ERK1/2. Insulin- and glargine-induced T24 cell proliferation was enhanced by PD98059, suppressed while not blocked by siMEK2. Insulin- and glargine-induced ERK1/2 activation was blocked by PD98059 or siMEK2 treatment, whereas activation of Akt was not affected.

CONCLUSIONMEK1 inhibits while MEK2 contributes to normal and human insulin- and insulin glargine-induced human bladder cancer T24 cell proliferation.

Blotting, Western ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Flavonoids ; pharmacology ; Humans ; Insulin ; pharmacology ; Insulin Glargine ; Insulin, Long-Acting ; pharmacology ; MAP Kinase Kinase 1 ; antagonists & inhibitors ; metabolism ; MAP Kinase Kinase 2 ; genetics ; metabolism ; MAP Kinase Signaling System ; drug effects ; genetics ; Phosphorylation ; drug effects ; RNA, Small Interfering ; genetics ; physiology ; Urinary Bladder Neoplasms ; metabolism