A Microfabricated Pistonless Syringe Pump Driven by Electro-Conjugate Fluid with Leakless On/Off Microvalves.

In contrast to microfluidic devices, bulky syringe pumps are widely used to deliver a small amount of solution with high accuracy. Miniaturizing the syringe pump is difficult due to the scale effect in the microscale where the friction of the piston-cylinder is dominant and there are few high-power microactuators. To solve these problems, an on-chip microsyringe pump without mechanical sliding parts and with high power sources is proposed. The microsyringe pump utilizes the interface between water and oil (electro-conjugate fluid, ECF) instead of a piston and an electrohydrodynamic (EHD) flow driven by ECF in place of a linear actuator. ECF as a functional fluid has two capabilities: a) making the water-oil interface in microchannels and b) generating an active ECF flow at an applied voltage to withdraw and infuse aqueous solution by the interface. To control the flow direction, ECF-driven leakless on/off microvalves are also integrated. It is demonstrated that the proposed ECF microsyringe pump synchronized with the ECF on/off microvalves can control the withdrawing and infusing of aqueous solution with high resolution and precision. The experiments prove the feasibility of the microsyringe pump to be embedded as a module for the precise and linear control of flow rates in microfluidic devices.

Nanopatterned Nafion microelectrode arrays for in vitro cardiac electrophysiology.

In this study, we report nanopatterned Nafion microelectrode arrays for in vitro cardiac electrophysiology. With the aim of defining sophisticated Nafion nanostructures with highly ionic conductivity, fabrication parameters such as Nafion concentration and curing temperature were optimized. By increasing curing temperature and Nafion concentration, we were able to control the replication fidelity of Nafion nanopatterns when copied from a PDMS master mold. We also found that cross-sectional morphology and ion current density of nanopatterned Nafion strongly depends on the fabrication parameters. To investigate this dependency, current-voltage analysis was conducted using organic electrochemical transistors (OECT) overlaid with patterned Nafion substrates. Nanopatterned Nafion was found to allow higher ion current densities than unpatterned surfaces. Furthermore, higher curing temperatures were found to render Nafion layers with higher ion/electrical transfer properties. To optimize nanopattern dimensions, electrical current flows, and film uniformity, a final configuration consisting of 5% nanopatterned Nafion cured at 65°C was chosen. Multielectrode arrays (MEAs) were then covered with optimized Nafion nanopatterns and used for electrophysiological analysis of two types of induced pluripotent stem cell-derived cardiomyocytes (iPSCs-CMs). These data highlight the suitability of nanopatterned Nafion, combined with MEAs, for enhancing the cellular environment of iPSC-CMs for use in electrophysiological analysis in vitro.

Elastic Inflatable Actuators for Soft Robotic Applications.

The 20th century's robotic systems have been made from stiff materials, and much of the developments have pursued ever more accurate and dynamic robots, which thrive in industrial automation, and will probably continue to do so for decades to come. However, the 21st century's robotic legacy may very well become that of soft robots. This emerging domain is characterized by continuous soft structures that simultaneously fulfill the role of robotic link and actuator, where prime focus is on design and fabrication of robotic hardware instead of software control. These robots are anticipated to take a prominent role in delicate tasks where classic robots fail, such as in minimally invasive surgery, active prosthetics, and automation tasks involving delicate irregular objects. Central to the development of these robots is the fabrication of soft actuators. This article reviews a particularly attractive type of soft actuators that are driven by pressurized fluids. These actuators have recently gained traction on the one hand due to the technology push from better simulation tools and new manufacturing technologies, and on the other hand by a market pull from applications. This paper provides an overview of the different advanced soft actuator configurations, their design, fabrication, and applications.

Cost-of-illness and quality of life in patients with ankylosing spondylitis at a tertiary hospital in Korea.

The objectives of this study were to estimate the cost-of-illness (COI) and health-related quality of life (HRQOL) in patients with ankylosing spondylitis (AS) in Korea and to evaluate the effects of socio-demographic and clinical factors on the COI and the HRQOL. Face-to-face interview surveys were taken from patients with AS at the Rheumatology Clinic of Seoul National University Hospital. Direct medical and non-medical costs, indirect costs (productivity loss due to job loss and sick leave), and deterioration of HRQOL in patients with AS were measured. Factors associated with COI and HRQOL were analyzed with multiple regression and multivariate logistic regression. A total of 191 patients with AS was enrolled in the study. The COI in patients with AS amounted to 11,646,180 Korean Won (KRW) per patient, and their HRQOL was 0.62. As functional severity worsened, the total costs increased (class I, KRW 7.7 million; class II, KRW 12.9 million; classes III & IV, KRW 25.2 million) and the HRQOL scores decreased (class I, 0.72; class II, 0.61; classes III & IV, 0.24). Functional severity is the major determinant of the COI and HRQOL in patients with AS.

Tofacitinib prevents radiographic progression in rheumatoid arthritis.

Tofacitinib, a novel Janus kinase inhibitor, may prevent structural damage in rheumatoid arthritis (RA). In this cohort study, we compared radiographic progression of hand joints between 21 RA patients who took tofacitinb for 18 months in a phase IIb and its extension study and 42 patients who took conventional disease modifying antirheumatic drugs (DMARDs), using simple erosion narrowing score. For tofacitinib group, changes before and after the treatment were also compared. The changes of erosion and sum scores were significantly less in tofacitinib than DMARDs group (for erosion, -0.60 ± 1.83 vs 0.51 ± 1.77, P = 0.038; for sum, -0.50 ± 1.72 vs 1.57 ± 4.13, P = 0.012). Joint space narrowing score (JSN) was also less in tofacitinib group (0.095 ± 0.58 vs 1.06 ± 2.60, P = 0.055). In tofacitinib group, yearly rates of both erosion and JSN were significantly decreased after administration of tofacitinib (For erosion, 0.62 ± 0.93 to -0.14 ± 0.48, P = 0.009; for JSN, 0.47 ± 0.64 to 0.03 ± 0.40, P = 0.032), as was change of sum score (1.09 ± 1.27 to -0.10 ± 0.63, P < 0.001). In conclusion, tofacitinib may prevent structural damage caused by RA.

The efficacy of diacerein in hand osteoarthritis: a double-blind, randomized, placebo-controlled study.

BACKGROUND: Diacerein is a drug used in osteoarthritis (OA) that elicits an inhibitory effect on interleukin-1 and metalloproteases. Although diacerein has shown modest efficacy and safety in the treatment of knee and hip OA, there have been no placebo-controlled clinical trials for hand OA. OBJECTIVE: The aim of the current study was to investigate the efficacy and tolerability of diacerein in patients with hand OA. METHODS: Patients fulfilling the American College of Rheumatology criteria for hand OA participated in this randomized, double-blind, placebo-controlled study. Eligible patients were >40 years of age, had at least 1 tender joint, and had a joint pain visual analog scale of >30 mm. Patients received diacerein (50 mg) or placebo BID for 12 weeks. The primary end point was the Australian/Canadian Osteoarthritis Hand Index (AUSCAN) pain score at 4 weeks. Secondary end points were AUSCAN pain score at 12 weeks and AUSCAN physical function and stiffness score, patient and physician global assessment, functional index of hand OA scores, and multidimensional health assessment questionnaire results at 4 weeks and 12 weeks. RESULTS: Eighty-six Korean patients were enrolled (42 diacerein, 44 placebo). The intention-to-treat and per-protocol analyses revealed no significant differences between the 2 groups in terms of change in AUSCAN pain score at 4 weeks, except for improvement in physician global assessment at 4 weeks (per-protocol analysis, P = 0.004). The safety profile of diacerein was comparable to placebo, except for frequent discoloration of the urine (88% vs 20%). CONCLUSION: These results suggest that diacerein 50 mg BID may be ineffective in controlling the symptoms of hand OA. ClinicalTrials.gov identifier: NCT00685542.

The clinicopathologic characteristics of granulomatosis with polyangiitis (Wegener's): a retrospective study of 45 patients in Korea.

OBJECTIVES: The aim of this study was to determine the clinicopathologic characteristics of granulomatosis with polyangiitis (Wegener's) (GPA) in Korean patients. METHODS: The medical records of 45 patients with GPA treated in a single tertiary referral hospital were retrospectively analyzed with respect to clinical manifestations, including histology, ANCA positivity, disease stage, and disease activity. Patients were categorized into granulomatous, vasculitic, or mixed form based on an immunopathologic scoring system of granulomatous-vasculitic activity. RESULTS: Thirty-one patients (68.9 %) showed ANCA positivity (C-ANCA/P-ANCA, 42.2 %/20.0 %, proteinase-3 (PR3) ANCA/myeloperoxidase (MPO) ANCA, 44.1 %/16.1 %), and these patients (female 48.4 %) were found to be associated with a higher frequency of renal involvement (51.6 vs. 7.1 %, p = 0.004), elevated serum creatinine (29.0 vs. 0 %, p = 0.018), and higher mortality (29 vs. 7.1 %, p = 0.041) than ANCA-negative patients. Thirty-three patients (73.3 %, female 60.6 %) had the granulomatous form, whereas 8.9 and 17.8 % had the vasculitic and mixed forms, respectively. Patients with the granulomatous form were diagnosed earlier in their lives (mean age 51.2 vs. 62.3, p = 0.002) and had a lower frequency of renal involvement (21.2 vs. 100 %, p = 0.005) compared with those with the vasculitic form. Initial remission (69.7 vs. 25.0 %) and relapse (60.8 vs. 0 %) rates were higher for the granulomatous than for the vasculitic form. CONCLUSIONS: Taken together, in Korean patients with GPA, the granulomatous form was predominant and associated with a younger age at diagnosis and a lower frequency of renal involvement than the vasculitic form. ANCA positivity was found in 68.9 % and associated with renal involvement and higher mortality.

Associations between the HLA-A polymorphism and the clinical manifestations of Behcet's disease.

INTRODUCTION: The objective was to investigate associations between the HLA-A gene and Behcet's disease (BD) and its clinical manifestations. METHODS: Genotyping for the HLA-A locus was performed using the polymerase chain reaction-Luminex typing method in 223 BD patients and 1,398 healthy controls. RESULTS: The phenotypic frequencies of HLA-A*02:07 (odds ratio (OR) = 2.03, P = 0.002), A*26:01 (OR = 1.85, P = 0.008), and A*30:04 (OR = 2.51, P = 0.006) tended to be higher in BD patients than in normal controls, but the frequency of A*33:03 (OR = 0.59, P = 0.003) tended to be lower in BD patients. A meta-analysis adopting our and the Japanese data confirmed the associations of HLA-A*02:07, A*26:01, and A*33:03 with BD. Furthermore, the frequencies of the HLA-A*02:07, A*26:01, and A*30:04 were significantly higher in patients with skin lesions (OR = 2.37, P < 0.0005, Pc < 0.012) and arthritis (OR = 2.32, P = 0.002, Pc = 0.048), with uveitis (OR = 3.01, P < 0.0005, Pc < 0.012), and with vascular lesions (OR = 9.80, P < 0.0005, Pc < 0.012) and a positive pathergy test (OR = 4.10, P = 0.002, Pc = 0.048), respectively, than in controls. In HLA-B*51 non-carriers, these associations were also significant, being much stronger between HLA-A*26:01 and uveitis (OR = 4.19, P < 0.0005, Pc < 0.012) and between HLA-A*30:04 and vascular lesions (OR = 13.97, P < 0.00005, Pc < 0.0012). In addition, HLA-A*30:04 was associated with genital ulcers in HLA-B*51 non-carriers (OR = 3.89, P = 0.002, Pc = 0.048). CONCLUSIONS: HLA-A*02:07, A*26:01, and A*30:04 were associated with increased risk for BD, while HLA-A*33:03 with decreased risk. HLA-A*02:07, A*26:01, and A*30:04 were associated with skin lesions and arthritis, with uveitis, and with vascular lesions, genital ulcers, and a positive pathergy test, respectively.

Indomethacin enhances shuttling of aquaporin-2 despite decreased abundance in rat kidney.

The effect of nonsteroidal antiinflammatory drugs on the regulation of aquaporin-2 (AQP2) water channels in the kidney was determined. Male Sprague-Dawley rats were injected with indomethacin (5 mg/kg twice a day intraperitoneally) for 2 d. The control group was injected with vehicle. The expression of AQP2 proteins was determined in the kidney by immunoblotting and immunohistochemistry. The expression of G(salpha) and type VI adenylyl cyclase was determined by immunoblotting. The activity of adenylyl cyclase complexes was determined by stimulated accumulation of cAMP. Immunoblotting revealed that indomethacin markedly decreased the expression of AQP2. Accordingly, however, the ratio of AQP2 expression in the membrane fraction versus that in the cytoplasmic fraction was increased. The urinary excretion of AQP2 proteins also increased. Immunohistochemistry demonstrated almost exclusive apical labeling of AQP2 with scanty cytoplasmic localization along the collecting duct. The expression of G(salpha) and adenylyl cyclase VI proteins was decreased. The generation of cAMP provoked by arginine vasopressin, sodium fluoride, or forskolin was blunted. These results suggest that indomethacin increases the shuttling of AQP2 while it decreases its abundance in the collecting duct.