A Novel Virus-Like Agent Originated From Genome Rearrangement of Porcine Circovirus Type 2 (PCV2) Enhances PCV2 Replication and Regulates Intracellular Redox Status In Vitro.

Genome rearrangement occurs to porcine circovirus type 2 (PCV2) during in vitro and in vivo infections, and a number of rearranged PCV2 genomes have been isolated and characterized. This study was conducted to investigate the role of the rearranged PCV2 (rPCV2) in PCV2 replication and the biological effect of rPCV2 in host cells. Two whole rPCV2 genome sequences (358 nt and 1125 nt in length) were synthesized and recombinant plasmids pBSK(+)-rPCV2 (pBSK(+)-1125 and pBSK(+)-358) were constructed. A novel virus-like agent (rPCV2-1125) was rescued by in vitro transfection of porcine kidney cell line (PK-15) and porcine alveolar macrophage 3D4/21 cells. The data indicate that rPCV2-1125 significantly enhanced PCV2 replication in vitro. Furthermore, rPCV2-1125 led to oxidative stress in host cells, as indicated by decreased intracellular glutathione (GSH) and total superoxide dismutase (SOD) activities, as well as increased malondialdehyde (MDA) levels. These results provide new insights into genome rearrangement of PCV2 and will contribute to future studies of PCV2 replication and associated mechanisms.

Enhancing signals of microfluidic impedance cytometry through optimization of microelectrode array.

Microfluidic impedance cytometry shows a great value in biomedical diagnosis. However, the crosstalk between neighboring microelectrodes strongly weakens the impedance signal. Hereby, we demonstrate a novel microfluidic impedance cytometer consisted of sensing electrodes and ground electrodes (GNDs). The simulation reveals a signal enhancement by more than five times with GNDs compared to that without ones. We also found that the linear correlation between the impedance at a high frequency and that at a low frequency varies as microparticle size changes, which can be used for microparticle classification. The study can help with microelectrode optimization and signal processing for microfluidic impedance analysis.

Recent advancement in induced-charge electrokinetic phenomena and their micro- and nano-fluidic applications.

Induced-charge electrokinetics (ICEK) remains a hot topic due to its promising applications in micro- and nano-fluidics. Over the past decade, researchers have made a great advancement in both fundamental studies and application developments. They captured (I) a flow reversal in induced-charge electroosmosis (ICEO) and attributed it to the phase delay effect of ions, (II) a chaotic ICEO and attributed it to the concentration polarization in the bulk solution, (III) a non-quadratic correlation for ICEO of non-Newtonian fluids and attributed it to the power-law viscosity, (IV) an induced-charge electrophoretic (ICEP) rotation of Janus doublets, etc. Furthermore, various ICEK-based micro- and nano-fluidic devices have been developed, namely, micropumps, particle focusers, trappers, sorters, and nanopore ion diodes. The present article provides a comprehensive review on the recent advancement of ICEK. Firstly, the fundamental studies of ICEK are introduced; then the micro- and nano-fluidic applications based on ICEK are presented; lastly, promising future directions for both fundamental and applications are discussed. This review presents the basic framework of ICEK, and can facilitate the development of ICEK-based applications.

Net fluid flow and non-Newtonian effect in induced-charge electro-osmosis of polyelectrolyte solutions.

This paper reports an interesting net fluid flow in the induced-charge electro-osmosis (ICEO) of poly(sodium 4-styrenesulfonate) (NaPSS) solutions measured through microparticle image velocimetry (µPIV). The net fluid flow is attributed to the significantly unequal cations and poly-anions of NaPSS. Owing to the phase delay effect of ions, different flow patterns appear with the alternating electric field. The inflow velocity and outflow velocity are found to be unequal and their relative magnitude shows a dependence on the electric field strength. The ICEO velocity is positively correlated with the NaPSS concentration. As NaPSS introduces the non-Newtonian effect, the well-known quadratic relationship between ICEO velocity and electric field strength in Newtonian fluids breaks. The ICEO velocity varies differently with the electric field strength as the NaPSS concentration changes. These new findings can contribute to the understanding of ICEO of complex fluids, e.g., biofluids.

MiR-92a inhibits fibroblast-like synoviocyte proliferation and migration in rheumatoid arthritis by targeting AKT2.

Growing data have indicated that the miR-17-92 cluster is implicated in inflammatory response and rheumatoid arthritis (RA). This study was aimed to investigate the effects of miR-92a on the proliferation and migration of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLSs). Our results showed that miR-92a was significantly down-regulated in RA synovial tissue and RA-FLSs, whereas the protein level of AKT2 is increased. Restoration of miR-92a suppressed the proliferation and migration of RA-FLSs. Down-regulation of miR-92a promotes proliferation and migration of normal human FLSs. Dual luciferase reporter gene assay showed that miR-92a could specifically bind with the 30UTR of AKT2 and significantly repressed the luciferase activity. Down-regulation or up-regulation of miR-92a significantly increased or decreased the protein and phosphorylation levels of AKT2. siRNA-mediated down-regulation of AKT2 significantly prevented cell proliferation and migration of RA-FLSs, which were similar to the effects induced by overexpression of miR-92a. Moreover, AKT2 overexpression rescued miR-92a-mediated suppressive effect on proliferation and migration of RA-FLS. Thus, miR-92a could inhibit the proliferation and migration of RA-FLSs through regulation of AKT2 expression.

Circular RNA expression profiles in synovial fluid: a promising new class of diagnostic biomarkers for osteoarthritis.

BACKGROUND: Previous studies suggest that circRNAs abnormally function in the progression of osteoarthritis (OA). However, little is known about the diagnostic value of circRNAs in patients with OA. To assess potential applications of circRNAs as diagnostic tools in OA, expression profiles of circRNAs in synovial fluid from OA patients and healthy subjects were obtained. METHODS: Microarray analysis was performed to profile the expression of circRNAs in an unbiased manner. CircRNA expression in synovial fluid was identified by real-time quantitative polymerase chain reaction (RT-qPCR). The diagnostic value was evaluated using receiver operating characteristics (ROC) curves and the area under the ROC curves (AUC). Spearman correlation analysis was performed to assess the correlation of circRNAs and clinical parameters. RESULTS: We identified five circRNAs that were significantly elevated in synovial fluid from OA patients compared with those of the healthy controls. Among these five circRNAs, hsa_circ_0104873, hsa_circ_0104595, and hsa_circ_0101251 could effectively separate patients with OA from healthy controls with high AUC (0.683, 0.708 and 0.754, respectively). Furthermore, we found that three circRNAs were positively correlated with the degree of radiographic grading and symptomatic severity of OA patients. CONCLUSION: This study suggests that increased expression of hsa_circ_0104873, hsa_circ_0104595, and hsa_circ_0101251 in synovial fluid from OA patients may serve as potential biomarkers for OA screening.

Electrolyte effect in induced charge electroosmosis.

This paper reports an interesting phenomenon that the velocity increases with increasing sodium chloride (NaCl) concentration in induced charge electroosmosis (ICEO) around a conducting cylinder measured by microparticle image velocimetry (µPIV). It is different from the widely reported velocity decay with increasing electrolyte concentration in AC electroosmosis (ACEO) [M. Z. Bazant et al., MicroTAS, 2007, 2875-2878] and induced charge electrophoresis (ICEP) of Janus particles [S. Gangwal et al., Phys. Rev. Lett., 2008, 100, 058302]. In addition, it is found that a reversed vortex flow emerges in deionized water. As the electric field increases or with a slight addition of NaCl, the ICEO vortex flow recovers. Different from the prediction of thin electric double layer (EDL) models, the observed ICEO flow is asymmetric with respect to the cylinder center. The asymmetry presents an electrolyte dependence, and it is intensified as the applied electric field increases. The ICEO flow obtains maximum values at certain electric field frequencies in NaCl and calcium chloride (CaCl2) solutions. But it is surprisingly insensitive to the electric field frequency in sodium dodecyl sulfate (NaDS) solutions. The optimum electric field frequency varies as electrolyte species change. A linear relationship between ICEO velocity and electric field strength squared is observed in all the examined electrolyte solutions, while the slope varies with the changing electrolyte species.

Octagon to Square Wetting Area Transition of Water-Ethanol Droplets on a Micropyramid Substrate by Increasing Ethanol Concentration.

The wettability and evaporation of water-ethanol binary droplets on the substrate with micropyramid cavities are studied by controlling the initial ethanol concentrations. The droplets form octagonal initial wetting areas on the substrate. As the ethanol concentration increases, the side ratio of the initial wetting octagon increases from 1.5 at 0% ethanol concentration to 3.5 at 30% ethanol concentration. The increasing side ratio indicates that the wetting area transforms from an octagon to a square if we consider the octagon to be a square with its four corners cut. The droplets experience a pinning-depinning transition during evaporation. The pure water sessile droplet evaporation demonstrates three stages from the constant contact line (CCL) stage, and then the constant contact angle (CCA) stage, to the mixed stage. An additional mixed stage is found between the CCL and CCA stages in the evaporation of water-ethanol binary droplets due to the anisotropic depinning along the two different axes of symmetry of the octagonal wetting area. Droplet depinning occurs earlier on the patterned surface as the ethanol concentration increases.

[Case-control studies on double bundle posterior cruciate ligament reconstruction with remnant fiber preservation].

OBJECTIVE: To study the clinical efficacy of double bundle posterior cruciate ligament (PCL) reconstruction with remnant preservation. METHODS: From January 2007 to November 2011, 50 patients with PCL rupture met the inclusion criteria were divided into two groups: remnant preservation group (RP group) and remnant resection group (RR group). There were 19 males and 7 females in the RP group, ranging in age from 18 to 55 years, with a mean of (32.250 +/- 11.085) years old. The duration from injury to operation ranged from 2 to 66 months, with an average of (17.481 +/- 3.568) months. Among the RR group, 17 patients were male and 7 patients were female, ranging in age from 20 to 54 years old, with an average of (31.458 +/- 9.569) years. The duration from injury to operation ranged from 3 to 72 months, with a mean of (19.354 +/- 3.950) months. The patients in both groups suffered from instability of knee joint, got a positive result of posterior drawer test. In the RP group, the intercondylar notch remnant fiber, scar tissue and synovial were preserved in operation, only the free ligament in the intercondylar notch was resected. In the RR group, the remnant fiber, scar tissue and synovial tissue of adhesive parts were resected. In both groups, autologous semitendinosus and gracilis tendon double-bundle PCL reconstruction were carried out, the tibia was fixed with an absorbable interference screw with post-tie fixation, and the femur side was compositely fixed with absorbable interference screws and suspending fixation. Each patient received both subjective assessment (IKDC subjective evaluation, Lysholm scoring and Cincinnati rating) and objective clinical assessment (IKDC objective evaluation and Kneelax 3 tibia backward measurement) before operation and two years after operation. RESULTS: IKDC subjective evaluation: 92.167 +/- 4.177 in the RP group,which was higher than 87.542 +/- 5.687 in the RR group (P = 0.010). Lysholm scores: 90.917 +/- 4.413 in the RP group, which was higher than 87.083 +/- 5.149 in the RR group (P = 0.027). Cincinnati knee scores: 92.125 +/- 4.003 in the RP group, which was higher than 87.791 +/- 6.665 in the RR group (P = 0.027). IKDC objective evaluation:no significant statistical differences between RP group and RR group. Kneelax 3 assessment : tibia backward test with Kneelax 3 under 132 N showed no significant statistical difference between RP group and RR group, which were (3.958 +/- 0.693) mm and (4.029 +/- 0.846) mm respectively (P = 0.795). CONCLUSION: The study shows a significant advantage of remnant fiber preservation than remnant fiber resection in double-bundle PCL construction in terms of subjective knee function recovery after operation. There is no significant difference in postoperative knee stability.