Protective effect of prostacyclin against pre-cardiac edema caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin and a thromboxane receptor agonist in developing zebrafish

The role of prostaglandin pathways has been suggested in some toxicological responses to dioxins. Cyclooxygenase type 2b (COX2b), thromboxane synthase, and the thromboxane receptor (TP) pathway have been implicated in mediating 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced pre-cardiac edema in developing zebrafish at 55 h post fertilization (hpf). Pre-cardiac edema refers to edema located in a small cavity between the heart and body wall of zebrafish eleutheroembryos. In the present study, we assessed the role of prostacyclin, which counteracts some biological effects of thromboxane, in TCDD-induced pre-cardiac edema. Pre-cardiac edema induced by TCDD exposure (0.5 and 1 ppb) beginning at 24 hpf was markedly inhibited by exposure to beraprost (5 and 10 μM), a prostacyclin receptor (IP) agonist, beginning at 33 hpf. The preventive effect of beraprost was reduced by exposure to CAY10441 (10 μM), an IP antagonist starting at 33 hpf. Knockdowns of the IP receptor (IP-KD) with two different morpholinos caused edema by themselves and enhanced pre-cardiac edema caused by the low concentration of TCDD (0.5 ppb). On the other hand, short exposure beginning at 48 hpf to U46619 (7.5-30 μM), a thromboxane receptor agonist caused pre-cardiac edema, which was inhibited by exposure beginning at 48 hpf to both ICI-192,605 (24 μM), a TP antagonist, and beraprost. Expression of prostacyclin synthase was increased from fertilization, plateaued by 48 hpf, and was maintained until at least 96 hpf. Overall, the results demonstrate a preventive effect of prostacyclin on TCDD-induced pre-cardiac edema in developing zebrafish.

Asymptotic Properties of a Mean-Field Model with a Continuous-State-Dependent Switching Process

This work is concerned with a class of mean-field models given by a switching diffusion with a continuous-state-dependent switching process. Focusing on asymptotic properties, the regularity or nonexplosiveness, Feller continuity, and strong Feller continuity are established by means of introducing certain auxiliary processes and by making use of the truncations. Based on these results, exponential ergodicity is obtained under the Foster–Lyapunov drift conditions. By virtue of the coupling methods, the strong ergodicity or uniform ergodicity in the sense of convergence in the variation norm is established for the mean-field model with a Markovian switching process. Besides this, several examples are presented for demonstration and illustration.

Countable-state-space Markov chains with two time scales and applications to queueing systems

Motivated by various applications in queueing systems, this work is devoted to continuous-time Markov chains with countable state spaces that involve both fast-time scale and slow-time scale with the aim of approximating the time-varying queueing systems by their quasistationary counterparts. Under smoothness conditions on the generators, asymptotic expansions of probability vectors and transition probability matrices are constructed. Uniform error bounds are obtained, and then sequences of occupation measures and their functionals are examined. Mean square error estimates of a sequence of occupation measures are obtained; a scaled sequence of functionals of occupation measures is shown to converge to a Gaussian process with zero mean. The representation of the variance of the limit process is also explicitly given. The results obtained are then applied to treat Mt/Mt/1 queues and Markov-modulated fluid buffer models.

Discrete-time singularly perturbed Markov chains: aggregation, occupation measures, and switching diffusion limit

This work is devoted to asymptotic properties of singularly perturbed Markov chains in discrete time. The motivation stems from applications in discrete-time control and optimization problems, manufacturing and production planning, stochastic networks, and communication systems, in which finite-state Markov chains are used to model large-scale and complex systems. To reduce the complexity of the underlying system, the states in each recurrent class are aggregated into a single state. Although the aggregated process may not be Markovian, its continuous-time interpolation converges to a continuous-time Markov chain whose generator is a function determined by the invariant measures of the recurrent states. Sequences of occupation measures are defined. A mean square estimate on a sequence of unscaled occupation measures is obtained. Furthermore, it is proved that a suitably scaled sequence of occupation measures converges to a switching diffusion.

Convergence of a global stochastic optimization algorithm with partial step size restarting

This work develops a class of stochastic global optimization algorithms that are Kiefer-Wolfowitz (KW) type procedures with an added perturbing noise and partial step size restarting. The motivation stems from the use of KW-type procedures and Monte Carlo versions of simulated annealing algorithms in a wide range of applications. Using weak convergence approaches, our effort is directed to proving the convergence of the underlying algorithms under general noise processes.

Kelvin probe imaging of photo-injected electrons in metal oxide nanosheets from metal sulfide quantum dots under remote photochromic coloration

Metal oxide and quantum dot (QD) heterostructures have attracted considerable recent attention as materials for developing efficient solar cells, photocatalysts, and display devices, thus nanoscale imaging of trapped electrons in these heterostructures provides important insight for developing efficient devices. In the present study, Kelvin probe force microscopy (KPFM) of CdS quantum dot (QD)-grafted Cs4W11O36(2-) nanosheets was performed before and after visible-light irradiation. After visible-light excitation of the CdS QDs, the Cs4W11O36(2-) nanosheet surface exhibited a decreased work function in the vicinity of the junction with CdS QDs, even though the Cs4W11O36(2-) nanosheet did not absorb visible light. X-ray photoelectron spectroscopy revealed that W(5+) species were formed in the nanosheet after visible-light irradiation. These results demonstrated that excited electrons in the CdS QDs were injected and trapped in the Cs4W11O36(2-) nanosheet to form color centers. Further, the CdS QDs and Cs4W11O36(2-) nanosheet composite films exhibited efficient remote photochromic coloration, which was attributed to the quantum nanostructure of the film. Notably, the responsive wavelength of the material is tunable by adjusting the size of QDs, and the decoloration rate is highly efficient, as the required length for trapped electrons to diffuse into the nanosheet surface is very short owing to its nanoscale thickness. The unique properties of this photochromic device make it suitable for display or memory applications. In addition, the methodology described in the present study for nanoscale imaging is expected to aid in the understanding of electron transport and trapping processes in metal oxide and metal chalcogenide heterostructure, which are crucial phenomena in QD-based solar cells and/or photocatalytic water-splitting systems.

Expression of G protein αq Subunit is Decreased in Lymphocytes from Patients with Rheumatoid Arthritis and is Correlated with Disease Activity

Gαq, the alpha subunit of Gq, a member of the Gq/11 sub-family, was reported to inhibit phosphatidylinositol-3-Kinase (PI3K) activation and prevent the activation of Akt. Previous studies demonstrated that mice losing Gαq in their immune system could spontaneously develop inflammatory arthritis. In this study, we showed that the Gαq expressions at mRNA and protein levels in the peripheral blood lymphocytes (PBLs) from patients with rheumatoid arthritis (RA) were significantly decreased in comparison of which in healthy individuals. The expression levels of Gαq mRNA in PBLs from patients with RA were correlated with RA disease activity (DAS28), anti-cyclic citrullinated protein antibodies, C-reactive protein and rheumatoid factor. We also demonstrated that Gαq controlled the apoptosis of RA PBLs through regulating the activity of Mcl-1 and caspase-3. These data suggested that Gαq might be involved in the pathogenesis of RA by regulating PBLs apoptosis.

Adenoviral vector-mediated overexpression of osteoprotegerin accelerates osteointegration of titanium implants in ovariectomized rats

This study investigated the efficacy of human osteoprotegerin (hOPG) transgene to accelerate osteointegration of titanium implant in ovariectomized (OVX) rats. Bone marrow stromal cells transduced with Ad-hOPG-EGFP could sustainedly express hOPG. Osteoclast precursor RAW264.7 cells treated by the hOPG were examined by tartrate-resistant acid phosphatase (TRAP) staining and bone slice resorption assay. The results showed differentiation and function of osteoclasts were significantly suppressed by hOPG in vitro. Ad-hOPG-EGFP was locally administered to the bone defect prior to implant placement in OVX and sham rats. After 3, 7, 28 days of implantation, the femurs were harvested for molecular and histological analyses. Successful transgene expression was confirmed by western blot and cryosectioning. A significant reduction in TRAP+ numbers was detected in Ad-hOPG-EGFP group. Real-time reverse transcriptase-PCR examination revealed that hOPG transgene markedly diminished the expression of cathepsin K and receptor activator for nuclear factor-κ B ligand in vivo. The transgene hOPG modification revealed a marked increasing osteointegration and restored implant stability in OVX rats (P<0.01), compared with the control groups (Ad-EGFP or sterilized phosphate-buffered saline) 28 days after implantation. In conclusion, hOPG via direct adenovirus-mediated gene transfer could accelerate osteointegration of titanium implants in OVX rats. Osteoprotegerin gene therapy may be an effective strategy to osteointegration of implants under osteoporotic conditions.

Protective effects of Lycium barbarum polysaccharides against carbon tetrachloride-induced hepatotoxicity in precision-cut liver slices in vitro and in vivo in common carp (Cyprinus carpio L.)

The protective effects of Lycium barbarum polysaccharides (LBPs) against carbon tetrachloride-induced hepatotoxicity in common carp were investigated in vitro and in vivo. Precision-cut liver slices (PCLSs) were employed as an in vitro model system. LBPs (0.1, 0.3 and 0.6 mg/ml) was added to PCLSs culture system before (pre-treatment), after (post-treatment) and both before and after (pre- and post-treatment) the exposure of PCLSs to 12 mM CCl4. The supernatants and PCLSs were collected for biochemical analyses. Results showed that LBPs inhibited the elevations of the marker enzymes (GOT, GPT, LDH and AKP) and MDA induced by CCl4 in all LBPs treatments and it also enhanced the suppressed antioxidant enzymes (SOD, CAT, GSH-Px, GST) and GSH, in the pre-treatment and pre- and post-treatment. In vivo, fish were fed diets containing LBPs at 0.1, 0.5 and 1% for 60 d before an intraperitoneal injection of 30% CCl4 in olive oil at a volume of 0.05 ml/10 g body weight. At 72 h post-injection, blood and liver samples were taken for biochemical analyses. Results showed that LBPs at 0.5 and 1% significantly reduced the levels of GOT, GPT and LDH in the serum; the decreases of the antioxidant enzymes and the increase of MDA in the liver tissue were inhibited markedly. Moreover, LBPs even at lower concentration exerted a potent DPPH scavenging activity. Overall results prove the hepatoprotective and antioxidant effects of LBPs and support the use of LBPs as a hepatoprotective agent in fish.

Effects of curcumin on antioxidative activities and cytokine production in Jian carp (Cyprinus carpio var. Jian) with CCl4-induced liver damage

We investigated the protective effects of curcumin on liver-damaged Cyprinus carpio var. Jian (Jian carp). The carp were fed 0.1%, 0.5%, or 1.0% curcumin for 60 days, then injected intraperitoneally with 30% carbon tetrachloride solution. Liver and blood samples were collected to measure the liver index, serum- and liver-associated enzymes, liver histology, nuclear factor-κB (NF-κB)/c-Rel, interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and IL-12 mRNA expression, and the level of NF-κB/c-Rel protein in the liver, and for a comet assay. We found that 0.5% and 1.0% curcumin significantly reduced the CCl(4)-induced increase in the liver index. The comet assay showed that the tail moment, olive tail moment, tail length, and tail DNA% improved in fish pretreated with 0.5 or 1.0% curcumin. CCl(4)-induced histological changes, including extensive hepatocyte degeneration, indistinct cell borders, nuclear condensation, and karyolysis were clearly reduced after treatment with 0.5% and 1.0% curcumin. Moreover, 0.5% and 1.0% curcumin significantly inhibited the CCl(4)-induced increase in serum glutamic oxaloacetic transaminase and promoted the restoration of superoxide dismutase in the liver; 1.0% curcumin significantly reduced serum glutamic pyruvic transaminase and lactate dehydrogenase and hepatic malondialdehyde, but significantly increased the total antioxidant capacity and glutathione levels in the liver. The CCl(4)-induced upregulation of NF-κB/c-Rel, IL-1β, and TNF-α mRNAs and NF-κB/c-Rel protein levels was inhibited by 0.5% and 1.0% curcumin, and IL-12 mRNA was reduced by all three doses of curcumin. The effects of curcumin on the liver index, enzymes, histological changes, and cytokines were dose-dependent. Our results indicate that curcumin reduces CCl(4)-induced liver damage in Jian carp by upregulating antioxidative activities and inhibiting NF-κB, IL-1β, TNF-α, and IL-12 expression.

Identification and functional characterization of novel feline cytochrome P450 2A

1. Cytochrome P450s are the major metabolizing enzymes for xenobiotics in humans and other mammals. Although the domestic cat Felis catus, an obligate carnivore, is the most common companion animal, the properties of cytochrome P450 subfamilies are largely unknown. 2. We newly identified the feline CYP2A13, which consists of 494 deduced amino acids, showing the highest identity to CYP2As of dogs, followed by those of pigs, cattle and humans. 3. The feline CYP2A13 transcript and protein were expressed almost exclusively in the liver without particular sex-dependent differences. 4. The feline CYP2A13 protein heterogeneously expressed in Escherichia coli showed metabolic activity similar to those of human and canine CYP2As for coumarin, 7-ethoxycoumarin and nicotine. 5. The results indicate the importance of CYP2A13 in systemic metabolism of xenobiotics in cats.

Efficient plasmonic scattering of colloidal silver particles through annealing-induced changes

We present an experimental study on the influence of annealing temperature on morphological changes of colloidal silver nanoparticles (Ag NPs) and their optical response. Monodisperse colloidal Ag NPs with diameter of 164 nm ± 15 nm have been fabricated by a facile two-step synthesis approach. The annealing effects on the Ag NPs have been investigated by means of optical measurements, scanning electron microscopy, x-ray photoelectron spectroscopy and x-ray diffraction. By annealing up to 440 °C morphology and chemical compositions of the Ag NPs changed. These changes affect the particle size and distribution, surface morphology, crystallinity and, most importantly, the oxidation state of the surface layer. The removal of an oxide layer leads to stronger light scattering from the nanoparticles and decreases parasitic light absorption at wavelengths above 400 nm. Strong light trapping has been observed for a silicon thin film with embedded annealed Ag NPs. This study demonstrates that colloidal Ag NPs for plasmonic solar cells need to be carefully processed and that they can potentially achieve high scatter efficiencies.

Reduction and the intracellular translocation of EphB2 in Tg2576 mice and the effects of β-amyloid

AIMS

EphB2 is a member of receptor tyrosine kinases (RTKs) family that is essential for the cell adhesion, neural crest migration, axon guidance and synaptogenesis in the nervous system. Recent studies show that preservation of EphB2 in a transgenic mouse model of Alzheimer's disease (AD) rescues the cognitive deficit, suggesting a crucial role of EphB2 in AD. However, the expression and distribution profiles of EphB2 in the early stage of AD have not been reported.

METHODS

Immunohistochemistry, immunoblot and immunofluorescence were used to analyse the level of EphB2 in Tg2576 mice at different ages and in cultured neurones with Aβ treatment at different times.

RESULTS

EphB2 was reduced in an age-dependent manner in the olfactory bulb and the hippocampus of Tg2576 mice. The decrease of EphB2 appeared earlier in the olfactory bulb than the hippocampus, and reduction of EphB2 appeared earlier than that of MAP2, a dendritic cytoskeleton marker. In the cortex, EphB2 displayed a significant translocation from the neuronal processes to the cell bodies with ageing. In primary hippocampal neuronal cultures, Aβ42 treatment also induced the decrement of EphB2 that was prior to the decline of MAP2.

CONCLUSIONS

Our findings provide the first evidence for an age- and region-dependent reduction and intracellular translocation of EphB2 in Tg2576 mice, and the foremost decrement of EphB2 in the olfactory bulb may represent an early sign of AD.

One-hour upright posture is an ideal position for serum aldosterone concentration and plasma renin activity measuring on primary aldosteronism screening

The serum aldosterone concentration (SAC) to plasma renin activity (PRA) ratio (ARR) is considered a useful screening test in the differential diagnosis of essential hypertension (EH) and primary aldosteronism (PA). The purpose of this study is to investigate the variation of ARR and compare the screening efficiency of it under different postures.37 patients with PA and 92 patients with EH were recruited in this study. Blood was sampled for measuring SAC and PRA under conditions of overnight recumbency, keeping upright posture for 1 h, 2 h and 4 h. The variation and screening efficiency of ARR under these conditions were compared according to repeated measured ANOVA and ROC curve analysis.In the EH group, ARR measured under recumbency posture was higher than those measured under keeping upright posture for 1 h and 2 h. In the PA group, there is no statistical difference for ARR between any 2 postures. AUCs of ARR measured under 4 conditions were 0.976, 0.995, 0.988, and 0.974 respectively. Cutoff values were ranging from 24.75 ng/dl per ng/ml/h under keeping upright for 2 h to 69.19 ng/dl per ng/ml/h under overnight recumbercy. ARR measured under keeping upright posture for 1 h produced the best characteristic of screening efficiency.Keeping upright posture for 1 h was the ideal position for ARR measuring and using a cutoff value of 35.90 ng/dl per ng/ml/h will have a sensitivity and specificity of 100.00% and 92.30% respectively.