miRNA-21 sensitizes gastrointestinal stromal tumors (GISTs) cells to Imatinib via targeting B-cell lymphoma 2 (Bcl-2).

OBJECTIVE: miRNA-21 (miRNA-21) has recently been recognized to tumor suppressive in various types of cancers. However, the role of miRNA-21 in gastrointestinal stromal tumors (GISTs) is still ambiguous. In this study, we investigated the regulation by miRNA-21 on the sensitivity of gastrointestinal stromal tumors (GISTs) cells to Imatinib. MATERIALS AND METHODS: We examined the expression of miRNA-21 and B-cell lymphoma 2 (Bcl-2) in GIST specimens by the real-time quantitative PCR assay (RT-qPCR). Then we explored the regulation by miRNA-21 on the Bcl-2 expression by the RT-qPCR assay, Western blotting assay and the luciferase assay in GIST-T1 cells. In addition, we examined the influence of miRNA-21 on the sensitivity to Imatinib of GIST-T1 cells with colony forming assay and apoptotic assay. RESULTS: Results indicated that miRNA-21 expression was suppressed in GIST tissues. And we identified putative miRNA-21 binding sites within the 3'-untranslated region (3'-UTR) of the human Bcl-2 gene. Transient transfection of miRNA-21 mimics into human GIST GIST-T1 cell line significantly downregulated the Bcl-2 expression in both mRNA and protein levels. Moreover, the miRNA-21 mimics transfection markedly aggravated the Imatinib-mediated growth inhibition and apoptosis induction in GIST-T1 cells. CONCLUSIONS: Our results demonstrated that miRNA-21 suppressed Bcl-2 expression in GIST cells and could function as a potent tumor suppressor in GIST. And the miRNA-21 promotion could sensitize GIST cells to Imatinib. It implies a potential role in the GIST treatment.

Purification and characterization of a potential antifungal protein from Bacillus subtilis E1R-J against Valsa mali.

In order to identify the antagonistic substances produced by Bacillus subtilis E1R-J as candidate of biocontrol agents for controlling Apple Valsa Canker, hydrochloric acid precipitation, reverse phase chromatography, gel filtration, and ion exchange chromatography were used. The purified fraction EP-2 showed a single band in native-polyacrylamide gel electrophoresis (native-PAGE) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Fraction EP-2 was eluted from native-PAGE and showed a clear inhibition zone against V. mali 03-8. These results prove that EP-2 is one of the most important antifungal substances produced by B. subtilis E1R-J in fermentation broth. SDS-PAGE and Nano-LC-ESI-MS/MS analysis results demonstrated that EP-2 was likely an antifungal peptide (trA0A086WXP9), with a relative molecular mass of 12.44 kDa and isoelectric point of 9.94. The examination of antagonistic mechanism under SEM and TEM showed that EP-2 appeared to inhibit Valsa mali 03-8 by causing hyphal swelling, distortion, abnormality and protoplasts extravasation. Inhibition spectrum results showed that antifungal protein EP-2 had significantly inhibition on sixteen kinds of plant pathogenic fungi. The stability test results showed that protein EP-2 was stable with antifungal activity at temperatures as high as 100 °C for 30 min and in pH values ranging from 1.0 to 8.0, or incubated with each 5 mM Cu(2+), Zn(2+), Mg(2+), or K(+). However, the antifungal activity was negatively affected by Proteinase K treatment.

Bone and muscle structure and quality preserved by active versus passive muscle exercise on a new stepper device in 21 days tail-suspended rats.

Human performance in microgravity is characterized by reversed skeletal muscle actions in terms of active vs. passive mode contractions of agonist/antagonist groups that may challenge principal biodynamics (biomechanical forces translated from muscle to bone) of the skeletal muscle-bone unit. We investigated active vs. passive muscle motions of the unloaded hindlimb skeletal muscle-bone unit in the 21 days tail-suspended (TS) rat using a newly designed stepper exercise device. The regimen included both active mode motions (TSA) and passive mode motions (TSP). A TS-only group and a normal cage group (CON) served as positive or negative controls. The muscle and bone decrements observed in TS-only group were not seen in the other groups except TSP. Active mode motions supported femur and tibia bone quality (5% BMD, 10% microtrabecular BV/TV, Tb.Th., Tb.N. parameters), whole soleus muscle/myofiber size and type II distribution, 20% increased sarcolemma NOS1 immunosignals vs. CON, with 25% more hybrid fiber formation (remodeling sign) for all TS groups. We propose a new custom-made stepper device to be used in the TS rat model that allows for detailed investigations of the unique biodynamic properties of the muscle-bone unit during resistive-load exercise countermeasure trials on the ground or in microgravity.

Changes in triphasic mechanical properties of proteoglycan-depleted articular cartilage extracted from osmotic swelling behavior monitored using high-frequency ultrasound.

This study aims to obtain osmosis-induced swelling strains of normal and proteoglycan (PG) depleted articular cartilage using an ultrasound system and to investigate the changes in its mechanical properties due to the PG depletion using a layered triphasic model. The swelling strains of 20 cylindrical cartilage-bone samples collected from different bovine patellae were induced by decreasing the concentration of bath saline and monitored by the ultrasound system. The samples were subsequently digested by a trypsin solution for approximately 20 min to deplete proteoglycans, and the swelling behaviors of the digested samples were measured again. The bi-layered triphasic model proposed in our previous study (Wang et al., J Biomech Eng-Trans ASME 2007; 129: 413-422) was used to predict the layered aggregate modulus Ha from the data of depth-dependent swelling strain, fixed charge density and water content. It was found that the region near the bone, for the normal specimens, had a significantly higher aggregate modulus (Ha1 = 20.6 +/- 18.2 MPa) in comparison with the middle zone and the surface layer (Ha2 = 7.8 +/- 14.5 MPa and Ha3 = 3.6 +/- 3.2 MPa, respectively) (p < 0.001). The normalized thickness of the deep layer h1 was 0.68 +/- 0.20. After the trypsin digestion, the parametric values decreased to Ha1 = 13.6 +/- 9.6 MPa, Ha2 = 6.7 +/- 11.5 MPa, Ha3 = 2.7 +/- 3.2 MPa, and h1 = 0.57 +/- 0.28. Other models were also used to analyze data and the results were compared. This study showed that high-frequency ultrasound measurement combined with the triphasic modeling was capable of nondestructively quantifying the alterations in the layered mechanical properties of the proteoglycan-depleted articular cartilage.

Stimulatory effect of components of rose flowers on catalytic activity and mRNA expression of superoxide dismutase and catalase in erythrocytes.

In the present study, two antioxidant components (polysaccharopeptide complex P(1-a) and condensed tannin P(1-b)) from rose (Rosa rugosa) flowers were each incubated with mouse erythrocytes to investigate their effect on erythrocyte superoxide dismutase (SOD), and catalase (CAT) activities. It was found that the activities of Cu, Zn-SOD and CAT were markedly increased after incubation for 3h with rose flower fractions at the concentration of 500µg/ml. Similar changes were also observed in the erythrocyte gene expression of SOD and CAT. These results show that P(1-a) and P(1-b) are effective antioxidants that increase the activity and the gene expression of SOD and CAT in mouse erythrocytes.

Extraction of mechanical properties of articular cartilage from osmotic swelling behavior monitored using high frequency ultrasound.

Articular cartilage is a biological weight-bearing tissue covering the bony ends of articulating joints. Negatively charged proteoglycan (PG) in articular cartilage is one of the main factors that govern its compressive mechanical behavior and swelling phenomenon. PG is nonuniformly distributed throughout the depth direction, and its amount or distribution may change in the degenerated articular cartilage such as osteoarthritis. In this paper, we used a 50 MHz ultrasound system to study the depth-dependent strain of articular cartilage under the osmotic loading induced by the decrease of the bathing saline concentration. The swelling-induced strains under the osmotic loading were used to determine the layered material properties of articular cartilage based on a triphasic model of the free-swelling. Fourteen cylindrical cartilage-bone samples prepared from fresh normal bovine patellae were tested in situ in this study. A layered triphasic model was proposed to describe the depth distribution of the swelling strain for the cartilage and to determine its aggregate modulus H(a) at two different layers, within which H(a) was assumed to be linearly dependent on the depth. The results showed that H(a) was 3.0+/-3.2, 7.0+/-7.4, 24.5+/-11.1 MPa at the cartilage surface, layer interface, and deep region, respectively. They are significantly different (p<0.01). The layer interface located at 70%+/-20% of the overall thickness from the uncalcified-calcified cartilage interface. Parametric analysis demonstrated that the depth-dependent distribution of the water fraction had a significant effect on the modeling results but not the fixed charge density. This study showed that high-frequency ultrasound measurement together with triphasic modeling is practical for quantifying the layered mechanical properties of articular cartilage nondestructively and has the potential for providing useful information for the detection of the early signs of osteoarthritis.

Ultrasonic measurement of depth-dependent transient behaviors of articular cartilage under compression.

We previously reported an ultrasound method for measuring the depth-dependent equilibrium mechanical properties of articular cartilage using quasi-static compression. The objective of this paper was to introduce our recent development for nondestructively measuring the transient depth-dependent strains of full-thickness articular cartilage specimens prepared from bovine patellae. A 50 MHz focused ultrasound transducer was used to collect ultrasound echoes from articular cartilage specimens (n=8) and sponge phantoms with open pores (n=10) during tests of compression and subsequent stress-relaxation. The transient displacements of the tissues at different depths along the compression direction were calculated from the ultrasound echoes using a cross-correlation tracking technique. An LVDT sensor and a load cell were used to measure the overall deformation of the tissue and the applied force, respectively. Results showed that the tissues inside the cartilage layer continued to move during the stress-relaxation phase after the compression was completed. In the equilibrium state, the displacements of the cartilage tissues at the depths of 1/4, 1/2, and 3/4 of the full-thickness reduced by 51%+/-22%, 54%+/-17%, and 50+/-17%, respectively, in comparison with its peak value. However, no similar phenomenon was observed in the sponge phantoms. Our preliminary results demonstrated that this ultrasound method may provide a potential tool for the nondestructive measurement of the transient depth-dependent processes involved in biological and bioengineered soft tissues as well as soft biomaterials under dynamic loading.

Enhancement of electrolarynx speech using adaptive noise cancelling based on independent component analysis.

The electrolarynx provides a valuable means of verbal communication for people who cannot use their natural voice-production mechanism, but technology has changed very little since it was introduced in the 1950s. The presence of background noise degrades the resulting speech. In this study background noise was reduced by a new method, independent component analysis-based adaptive noise cancelling, which can remove noise components of the primary input signal based on statistical independence, by incorporating both second-order and higher-order statistics. The method shows better performance than the conventional least mean square algorithm. Acoustic analysis of the denoised electrolarynx speech revealed a significant reduction in the amount of background noise. Results from the perceptual evaluations indicated that the new filtering technique produced a noticeable improvement in the acceptability of the electrolarynx speech in a quiet environment (from 1.75 to 2.49, arbitrary units) or a noisy environment (from 0.59 to 1.82). In general, there was no significant improvement or degradation in intelligibility in the quiet environment (from 52.7 to 53.3). However, the processing did improve the intelligibility in a babble-noise environment (from 24.9 to 40.6). The improvement in acceptability and intelligibility may increase the communication ability of the user in daily situations.

Disordered nanocrystalline superconducting PbMo6S8 with a very large upper critical field.

Large increases in the upper critical field B(C2)(0) are reported in bulk superconductors that demonstrate another novel property for nanocrystalline materials. Disordered nanocrystalline PbMo6S8 superconductors were fabricated by mechanical milling and hot isostatic pressing. Conventional PbMo6S8 has B(C2)(0) approximately 50 T. The nanocrystalline materials have higher resistivity (rho(N)) and B(C2)(0) approximately 100 T. The disorder produced in these nanocrystalline materials is significantly different from that produced by doping because it increases rho(N) and, hence, B(C2)(0) without significantly reducing the electronic density of states or superconducting transition temperature (T(C)). Furthermore, the disorder reduces the electron mean-free path to approximately 1 nm which is more than an order of magnitude smaller than the grain size and necessary to achieve the unprecedented increase in B(C2)(0).