Highlights • SE changed the expressions and subcellular localizations of TJ proteins. • The alteration in zonula occludens-1 expression was relevant to vasogenic edema. • ETB receptor-mediated eNOS ...activation increased MMP-9 activity. • ETB receptor antagonism prevented ZO-1 degradation by inhibiting MMP-9 activation. • ZO-1 degradation may be involved in vasogenic edema formation following SE.
Axonal degeneration is central to clinical disability and disease progression in multiple sclerosis (MS). Myeloid cells such as brain-resident microglia and blood-borne monocytes are thought to be ...critically involved in this degenerative process. However, the exact underlying mechanisms have still not been clarified. We have previously demonstrated that human endogenous retrovirus type W (HERV-W) negatively affects oligodendroglial precursor cell (OPC) differentiation and remyelination via its envelope protein pathogenic HERV-W (pHERV-W) ENV (formerly MS-associated retrovirus MSRV-ENV). In this current study, we investigated whether pHERV-W ENV also plays a role in axonal injury in MS. We found that in MS lesions, pHERV-W ENV is present in myeloid cells associated with axons. Focusing on progressive disease stages, we could then demonstrate that pHERV-W ENV induces a degenerative phenotype in microglial cells, driving them toward a close spatial association with myelinated axons. Moreover, in pHERV-W ENV-stimulated myelinated cocultures, microglia were found to structurally damage myelinated axons. Taken together, our data suggest that pHERV-W ENV-mediated microglial polarization contributes to neurodegeneration in MS. Thus, this analysis provides a neurobiological rationale for a recently completed clinical study in MS patients showing that antibody-mediated neutralization of pHERV-W ENV exerts neuroprotective effects.
Highlights • TRPC6 plays an important role in neuronal activity and neuronal survivals. • TRPC6 expression was down-regulated in the dentate gyrus in epileptic rats. • TRPC6 knockdown increased ...seizure susceptibility in the rat dentate gyrus. • TRPC6 knockdown promoted programed necrosis in dentate granule cells following SE. • TRPC6 may inhibit seizure susceptibility and SE-induced neuronal damage.
Background
Use of polysomnography (PSG) is the gold standard of diagnosis and measurement of treatment effectiveness for paediatric obstructive sleep apnoea (OSA). Although adenotonsillectomy (T&A) ...is effective in diminishing the apnoea–hypopnoea index (AHI), a meta‐analysis of postoperative changes for all other PSG parameters and outcome comparisons between obese and non‐obese children following T&A have never been conducted.
Objective of review
To comprehensively review polysomnographic findings after surgery for obese and non‐obese children with OSA.
Search strategy
Study protocol was registered on PROSPERO (CRD42013004737). Two authors independently searched databases including PubMed, MEDLINE, EMBASE and Cochrane Review from January 1997 to July 2014. The keywords used included the following: sleep apnea, OSA, sleep apnea syndromes, tonsillectomy, adenoidectomy, infant, child, adolescent, and Humans.
Evaluation method
A comprehensive systematic review and meta‐analysis for literature for OSA children treated by T&A with polysomnography data. Random‐effects model was applied to determine postoperative sleep parameter changes and the surgical success rate between obese and non‐obese groups. The quality of studies was assessed using the Newcastle–Ottawa Scale.
Results
In total, 51 studies with 3413 subjects were enrolled. After surgery, sleep architecture was altered by a significant decrease in sleep stage 1, and an increase in slow‐wave sleep and the rapid eye movement stage, and enhanced sleep efficiency. The mean difference between pre‐ and postoperative was a significant reduction of 12.4 event/h in AHI, along with a reduction of obstructive index, hypopnoea index, central index and arousal index. Mean and minimum oxygen saturation increased significantly after surgery. The overall success rate was 51% for postoperative AHI <1 (obese versus non‐obese versus combined, 34% versus 49% versus 56%), and 81% for AHI <5 (obese versus non‐obese versus combined, 61% versus 87% versus 84%). Meta‐regression analyses demonstrate that postoperative AHI was positively correlated with AHI and body mass index z score before surgery.
Conclusions
Meta‐analysis of current literature shows T&A offers prominent improvement in a variety of sleep parameters. Improvements in non‐obese children exceeded those for obese children. Postoperative residual OSA remained in roughly half of the children, especially those with severe disease and obesity, making additional treatment strategies and/or long‐term follow‐up highly desirable.
The efficiency of generating electricity from heat using concentrated solar power plants (which use mirrors or lenses to concentrate sunlight in order to drive heat engines, usually involving ...turbines) may be appreciably increased by operating with higher turbine inlet temperatures, but this would require improved heat exchanger materials. By operating turbines with inlet temperatures above 1,023 kelvin using closed-cycle high-pressure supercritical carbon dioxide (sCO
) recompression cycles, instead of using conventional (such as subcritical steam Rankine) cycles with inlet temperatures below 823 kelvin
, the relative heat-to-electricity conversion efficiency may be increased by more than 20 per cent. The resulting reduction in the cost of dispatchable electricity from concentrated solar power plants (coupled with thermal energy storage
) would be an important step towards direct competition with fossil-fuel-based plants and a large reduction in greenhouse gas emissions
. However, the inlet temperatures of closed-cycle high-pressure sCO
turbine systems are limited
by the thermomechanical performance of the compact, metal-alloy-based, printed-circuit-type heat exchangers used to transfer heat to sCO
. Here we present a robust composite of ceramic (zirconium carbide, ZrC) and the refractory metal tungsten (W) for use in printed-circuit-type heat exchangers at temperatures above 1,023 kelvin
. This composite has attractive high-temperature thermal, mechanical and chemical properties and can be processed in a cost-effective manner. We fabricated ZrC/W-based heat exchanger plates with tunable channel patterns by the shape-and-size-preserving chemical conversion of porous tungsten carbide plates. The dense ZrC/W-based composites exhibited failure strengths of over 350 megapascals at 1,073 kelvin, and thermal conductivity values two to three times greater than those of iron- or nickel-based alloys at this temperature. Corrosion resistance to sCO
at 1,023 kelvin and 20 megapascals was achieved
by bonding a copper layer to the composite surface and adding 50 parts per million carbon monoxide to sCO
. Techno-economic analyses indicate that ZrC/W-based heat exchangers can strongly outperform nickel-superalloy-based printed-circuit heat exchangers at lower cost.
Recent progress in controlled radical polymerizations, in particular atom transfer radical polymerization (ATRP), has provided a unique means for the design and synthesis of bioactive surfaces and ...functional biomaterials. This review summarizes such recent research activities. The synthesis strategies of bioactive surfaces and biomaterials via ATRP are described in detail. The highly robust and versatile ATRP technique is particularly suited for the preparation of functional bioactive surfaces, including antifouling, antibacterial, stimuli-responsive, biomolecule-coupled and micropatterned surfaces. In addition to bioactive surfaces, ATRP has also been widely used for the preparation of well-structured functional biomaterials, such as micellar delivery systems, hydrogels, cationic gene carriers and polymer–protein conjugates. The research activities in the last decade indicate that ATRP has become an essential tool for the design and synthesis of advanced, noble and novel biomaterials.
Glucose-6-phosphate dehydrogenase (G6PD) is a key enzyme that generates NADPH to maintain reduced glutathione (GSH), which scavenges reactive oxygen species (ROS) to protect cancer cell from ...oxidative damage. In this study, we mainly investigate the potential roles of G6PD in colorectal cancer (CRC) development and chemoresistance. We discover that G6PD is overexpressed in CRC cells and patient specimens. High expression of G6PD predicts poor prognosis and correlated with poor outcome of oxaliplatin-based first-line chemotherapy in patients with CRC. Suppressing G6PD decreases NADPH production, lowers GSH levels, impairs the ability to scavenge ROS levels, and enhances oxaliplatin-induced apoptosis in CRC via ROS-mediated damage in vitro. In vivo experiments further shows that silencing G6PD with lentivirus or non-viral gene delivery vector enhances oxaliplatin anti-tumor effects in cell based xenografts and PDX models. In summary, our finding indicated that disrupting G6PD-mediated NADPH homeostasis enhances oxaliplatin-induced apoptosis in CRC through redox modulation. Thus, this study indicates that G6PD is a potential prognostic biomarker and a promising target for CRC therapy.
Multiple sclerosis (MS) is the most frequent demyelinating disease in young adults and despite significant advances in immunotherapy, disease progression still cannot be prevented. Promotion of ...remyelination, an endogenous repair mechanism resulting in the formation of new myelin sheaths around demyelinated axons, represents a promising new treatment approach. However, remyelination frequently fails in MS lesions, which can in part be attributed to impaired differentiation of oligodendroglial progenitor cells into mature, myelinating oligodendrocytes. The reasons for impaired oligodendroglial differentiation and defective remyelination in MS are currently unknown. To determine whether intrinsic oligodendroglial factors contribute to impaired remyelination in relapsing–remitting MS (RRMS), we compared induced pluripotent stem cell-derived oligodendrocytes (hiOL) from RRMS patients and controls, among them two monozygous twin pairs discordant for MS. We found that hiOL from RRMS patients and controls were virtually indistinguishable with respect to remyelination-associated functions and proteomic composition. However, while analyzing the effect of extrinsic factors we discovered that supernatants of activated peripheral blood mononuclear cells (PBMCs) significantly inhibit oligodendroglial differentiation. In particular, we identified CD4
+
T cells as mediators of impaired oligodendroglial differentiation; at least partly due to interferon-gamma secretion. Additionally, we observed that blocked oligodendroglial differentiation induced by PBMC supernatants could not be restored by application of oligodendroglial differentiation promoting drugs, whereas treatment of PBMCs with the immunomodulatory drug teriflunomide prior to supernatant collection partly rescued oligodendroglial differentiation. In summary, these data indicate that the oligodendroglial differentiation block is not due to intrinsic oligodendroglial factors but rather caused by the inflammatory environment in RRMS lesions which underlines the need for drug screening approaches taking the inflammatory environment into account. Combined, these findings may contribute to the development of new remyelination promoting strategies.
Essential oils are known to possess antimicrobial and antioxidant activity while chitosan is a biocompatible polymer with antibacterial activity against a broad spectrum of bacteria. In this work, ...nanoparticles with both antioxidant and antibacterial properties were prepared by grafting eugenol and carvacrol (two components of essential oils) on chitosan nanoparticles. Aldehyde groups were first introduced in eugenol and carvacrol, and the grafting of these oils to chitosan nanoparticles was carried out via the Schiff base reaction. The surface concentration of the grafted essential oil components was determined by X-ray photoelectron spectroscopy (XPS). The antioxidant activities of the carvacrol-grafted chitosan nanoparticles (CHCA NPs) and the eugenol-grafted chitosan nanoparticles (CHEU NPs) were assayed with diphenylpicrylhydrazyl (DPPH). Antibacterial assays were carried out with a representative gram-negative bacterium, Escherichia coli (E. coli) and a gram-positive bacterium, Staphylococcus aureus (S. aureus). The grafted eugenol and carvacrol conferred antioxidant activity to the chitosan nanoparticles, and the essential oil component-grafted chitosan nanoparticles achieved an antibacterial activity equivalent to or better than that of the unmodified chitosan nanoparticles. Cytotoxicity assays using 3T3 mouse fibroblast showed that the cytotoxicity of CHEU NPs and CHCA NPs were significant lower than those of the pure essential oils. Biotechnol. Bioeng. 2009; 104: 30-39
Metals are widely used in engineering as well as medical applications. However, their surfaces are easily colonized by bacteria that form biofilms. Among the numerous concerns with biofilm formation, ...biocorrosion is of particular importance in industry, because structural integrity may be compromised, leading to technical failures. In the food industry and medical field, biofilms also pose health risks. To inhibit bacterial colonization, the surfaces of metals can be coated with a polymeric layer which is antiadhesive and/or bactericidal. This article describes polymers that have these desired properties and the methodologies for immobilizing them on metal surfaces of relevance to the marine and medical fields. The focus is on polymer coatings that have a high degree of stability in aqueous medium and do not leach out. The efficacies of the different polymer coatings against bacteria commonly encountered in marine (Desulfovibrio desulfuricans) and medical applications (Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli) are demonstrated.
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