To cite this article: Hong S-W, Kim M-R, Lee E-Y, Kim JH, Kim Y-S, Jeon SG, Yang J-M, Lee B-J, Pyun B-Y, Gho YS, Kim Y-K. Extracellular vesicles derived from Staphylococcus aureus induce atopic ...dermatitis-like skin inflammation. Allergy 2011; 66: 351-359. ABSTRACT: Background: Recently, we found that Staphylococcus aureus produces extracellular vesicles (EV) that contain pathogenic proteins. Although S. aureus infection has been linked with atopic dermatitis (AD), the identities of the causative agents from S. aureus are controversial. We evaluated whether S. aureus-derived EV are causally related to the pathogenesis of AD. Methods: Extracellular vesicles were isolated by the ultracentrifugation of S. aureus culture media. The EV were applied three times per week to tape-stripped mouse skin. Inflammation and immune dysfunction were evaluated 48 h after the final application in hairless mice. Extracellular vesicles-specific IgE levels were measured by ELISA in AD patients and healthy subjects. Results: The in vitro application of S. aureus EV increased the production of pro-inflammatory mediators (IL-6, thymic stromal lymphopoietin, macrophage inflammatory protein-1α, and eotaxin) by dermal fibroblasts. The in vivo application of S. aureus EV after tape stripping caused epidermal thickening with infiltration of the dermis by mast cells and eosinophils in mice. These changes were associated with the enhanced cutaneous production of IL-4, IL-5, IFN-γ, and IL-17. Interestingly, the serum levels of S. aureus EV-specific IgE were significantly increased in AD patients relative to healthy subjects. Conclusion: These results indicate that S. aureus EV induce AD-like inflammation in the skin and that S. aureus-derived EV are a novel diagnostic and therapeutic target for the control of AD.
Background
Recent evidence indicates that Staphylococcus aureus, one of the most important human pathogens, secretes vesicles into the extracellular milieu.
Objective
To evaluate whether inhalation ...of S. aureus‐derived extracellular vesicles (EV) is causally related to the pathogenesis of inflammatory pulmonary diseases.
Methods
Staphylococcus aureus EV were prepared by sequential ultrafiltration and ultracentrifugation. The innate immune response was evaluated in vitro after the application of EV to airway epithelial cells and alveolar macrophages. In vivo innate and adaptive immune responses were evaluated after airway exposure to EV. Adjuvant effects of EV on the development of hypersensitivity to inhaled allergens were also evaluated after airway sensitization with S. aureus EV and ovalbumin (OVA).
Results
Staphylococcus aureus and S. aureus EV were detected in house dust. Alveolar macrophages produced both tumor necrosis α (TNF‐α) and interleukin 6 (IL‐6) after in vitro stimulation with S. aureus EV, whereas airway epithelial cells produced only IL‐6. Repeated airway exposure to S. aureus EV induced both Th1 and Th17 cell responses and neutrophilic pulmonary inflammation, mainly via a Toll‐like receptor 2 (TLR2)‐dependent mechanism. In terms of adjuvant effects, airway sensitization with S. aureus EV and OVA resulted in neutrophilic pulmonary inflammation after OVA challenge alone. This phenotype was partly reversed by the absence of interferon γ (IFN‐γ) or IL‐17.
Conclusion
Staphylococcus aureus EV can induce Th1 and Th17 neutrophilic pulmonary inflammation, mainly in a TLR2‐dependent manner. Additionally, S. aureus EV enhance the development of airway hypersensitivity to inhaled allergens.
The enhancement of the functional properties of materials at reduced dimensions is crucial for continuous advancements in nanoelectronic applications. Here, we report that the scale reduction leads ...to the emergence of an important functional property, ferroelectricity, challenging the long-standing notion that ferroelectricity is inevitably suppressed at the scale of a few nanometers. A combination of theoretical calculations, electrical measurements, and structural analyses provides evidence of room-temperature ferroelectricity in strain-free epitaxial nanometer-thick films of otherwise nonferroelectric strontium titanate (SrTiO3). We show that electrically induced alignment of naturally existing polar nanoregions is responsible for the appearance of a stable net ferroelectric polarization in these films. This finding can be useful for the development of low-dimensional material systems with enhanced functional properties relevant to emerging nanoelectronic devices.
Despite the emerging importance of fibroblast growth factor 21 (FGF21) as a metabolic hormone regulating energy balance, its direct effects on renal function remain unexplored. FGF21 was injected ip ...daily for 12 weeks into db/db mice. Compared with control vehicle injection, FGF21 treatment significantly improved lipid profiles and insulin resistance and resulted in significantly higher serum adiponectin levels. In contrast, serum insulin and 8-isoprostane levels were significantly decreased. Interestingly, FGF21 and its receptor components in the kidneys were found to be significantly up-regulated in db/db mice, which suggests an FGF21-resistant state. FGF21 treatment significantly down-regulated FGF21 receptor components and activated ERK phosphorylation. FGF21 administration also markedly decreased urinary albumin excretion and mesangial expansion and suppressed profibrotic molecule synthesis. Furthermore, FGF21 improved renal lipid metabolism and oxidative stress injury. In cultured renal cells, FGF21 was mainly expressed in mesangial cells, and knockdown of FGF21 expression by stealth small interfering RNA further aggravated high-glucose-induced profibrotic cytokine synthesis in mesangial cells. Our results suggest that FGF21 improves insulin resistance and protects against renal injury through both improvement of systemic metabolic alterations and antifibrotic effects in type 2 diabetic nephropathy. Targeting FGF21 could therefore provide a potential candidate approach for a therapeutic strategy in type 2 diabetic nephropathy.
Background
Patients with a previous history of hypersensitivity reaction (HSR) to iodinated contrast media (ICM) are at high risk of the development of HSR to ICM. Many studies have tried to evaluate ...the diagnostic potential of skin tests in this population but have not yet reached a common conclusion. We investigated the role of skin tests in patients with HSR to ICM in terms of positive rate, cross‐reactivity rate, and tolerability to skin test‐negative ICM according to the type of HSR.
Methods
We performed literature searches of the MEDLINE and EMBASE databases and included studies where skin tests were performed in patients with HSR to ICM, with extractable outcomes. Outcomes were pooled using a random‐effects model.
Results
Twenty‐one studies were included. Pooled per‐patient positive rates of skin tests were 17% (95% CI, 10–26%) in patients with immediate HSR, and up to 52% (95% CI, 31–72%) when confined to severe immediate HSR. Among patients with nonimmediate HSR, the positive rate was 26% (95% CI, 15–41%). The pooled per‐patient cross‐reactivity rate was higher in nonimmediate HSR (68%; 95% CI, 48–83%) than that in immediate HSR (39%; 95% CI, 29–50%). Median per‐test cross‐reactivity rates between pairs of ICM were 7% (IQR, 6–9%) in immediate HSR and 38% (IQR, 22–51%) in nonimmediate HSR. Pooled per‐patient recurrence rates of HSR to skin test‐negative ICM were 7% (95% CI, 4–14%) in immediate HSR and 35% (95% CI, 19–55%) in nonimmediate HSR.
Conclusion
Skin tests may be helpful in diagnosing and managing patients with HSR to ICM, especially in patients with severe immediate HSR.
Separating structure and electrons in VO2Above 341 kelvin—not far from room temperature—bulk vanadium dioxide (VO2) is a metal. But as soon as the material is cooled below 341 kelvin, VO2 turns into ...an insulator and, at the same time, changes its crystal structure from rutile to monoclinic. Lee et al. studied the peculiar behavior of a heterostructure consisting of a layer of VO2 placed underneath a layer of the same material that has a bit less oxygen. In the VO2 layer, the structural transition occurred at a higher temperature than the metal-insulator transition. In between those two temperatures, VO2 was a metal with a monoclinic structure—a combination that does not occur in the absence of the adjoining oxygen-poor layer.Science, this issue p. 1037The metal-insulator transition in correlated materials is usually coupled to a symmetry-lowering structural phase transition. This coupling not only complicates the understanding of the basic mechanism of this phenomenon but also limits the speed and endurance of prospective electronic devices. We demonstrate an isostructural, purely electronically driven metal-insulator transition in epitaxial heterostructures of an archetypal correlated material, vanadium dioxide. A combination of thin-film synthesis, structural and electrical characterizations, and theoretical modeling reveals that an interface interaction suppresses the electronic correlations without changing the crystal structure in this otherwise correlated insulator. This interaction stabilizes a nonequilibrium metallic phase and leads to an isostructural metal-insulator transition. This discovery will provide insights into phase transitions of correlated materials and may aid the design of device functionalities.
We determined the fecal carriage rate of serotype K1
Klebsiella pneumoniae
in healthy Koreans and studied their genetic relationship with liver abscess isolates. We compared the carriage according to ...the country of residence. The stool specimens were collected through health promotion programs in Korea.
K. pneumoniae
strains were selected and tested for K1 by PCR. Serotype K1 isolates were characterized by multilocus sequence typing and pulsed field gel electrophoresis. A total of 248
K. pneumoniae
isolates were obtained from 1,174 Koreans. Serotype K1 was identified in 57 (4.9%), of which 54 (94.7%) were ST 23 and were closely related to the liver abscess isolates. Participants aged >25 years showed a higher fecal carriage rate than those ≤ 25 (
P
= 0.007). The proportion of serotype K1 out of
K. pneumoniae
isolates in foreigners of Korean ethnicity who had lived in other countries was lower compared with those who had lived in Korea (5.6% vs 24.1%,
P
= 0.024). A substantial proportion of Koreans >25 years carries serotype K1
K. pneumoniae
ST23 strains, which are closely related to liver abscess isolates. Differences in carriage rates by country of residence suggests that environmental factors might play an important role in the carriage of this strain.
High-temperature copper oxide superconductors consist of stacked CuO
planes, with electronic band structures and magnetic excitations that are primarily two-dimensional
, but with superconducting ...coherence that is three-dimensional. This dichotomy highlights the importance of out-of-plane charge dynamics, which has been found to be incoherent in the normal state
within the limited range of momenta accessible by optics. Here we use resonant inelastic X-ray scattering to explore the charge dynamics across all three dimensions of the Brillouin zone. Polarization analysis of recently discovered collective excitations (modes) in electron-doped copper oxides
reveals their charge origin, that is, without mixing with magnetic components
. The excitations disperse along both the in-plane and out-of-plane directions, revealing its three-dimensional nature. The periodicity of the out-of-plane dispersion corresponds to the distance between neighbouring CuO
planes rather than to the crystallographic c-axis lattice constant, suggesting that the interplane Coulomb interaction is responsible for the coherent out-of-plane charge dynamics. The observed properties are hallmarks of the long-sought 'acoustic plasmon', which is a branch of distinct charge collective modes predicted for layered systems
and argued to play a substantial part in mediating high-temperature superconductivity
.
Fast radio bursts (FRBs) are millisecond-duration radio transients of unknown physical origin observed at extragalactic distances
. It has long been speculated that magnetars are the engine powering ...repeating bursts from FRB sources
, but no convincing evidence has been collected so far
. Recently, the Galactic magnetar SRG 1935+2154 entered an active phase by emitting intense soft γ-ray bursts
. One FRB-like event with two peaks (FRB 200428) and a luminosity slightly lower than the faintest extragalactic FRBs was detected from the source, in association with a soft γ-ray/hard-X-ray flare
. Here we report an eight-hour targeted radio observational campaign comprising four sessions and assisted by multi-wavelength (optical and hard-X-ray) data. During the third session, 29 soft-γ-ray repeater (SGR) bursts were detected in γ-ray energies. Throughout the observing period, we detected no single dispersed pulsed emission coincident with the arrivals of SGR bursts, but unfortunately we were not observing when the FRB was detected. The non-detection places a fluence upper limit that is eight orders of magnitude lower than the fluence of FRB 200428. Our results suggest that FRB-SGR burst associations are rare. FRBs may be highly relativistic and geometrically beamed, or FRB-like events associated with SGR bursts may have narrow spectra and characteristic frequencies outside the observed band. It is also possible that the physical conditions required to achieve coherent radiation in SGR bursts are difficult to satisfy, and that only under extreme conditions could an FRB be associated with an SGR burst.
Starting from Tesla's principles of wireless power transfer a century ago, this critical review outlines recent magneto-inductive research activities on wireless power transfer with the transmission ...distance greater than the transmitter coil dimension. It summarizes the operating principles of a range of wireless power research into 1) the maximum power transfer and 2) the maximum energy efficiency principles. The differences and the implications of these two approaches are explained in terms of their energy efficiency and transmission distance capabilities. The differences between the system energy efficiency and the transmission efficiency are also highlighted. The review covers the two-coil systems, the four-coil systems, the systems with relay resonators and the wireless domino-resonator systems. Related issues including human exposure issues and reduction of winding resistance are also addressed. The review suggests that the use of the maximum energy efficiency principle in the two-coil systems is suitable for short-range rather than mid-range applications, the use of the maximum power transfer principle in the four-coil systems is good for maximizing the transmission distance, but is under a restricted system energy efficiency (<;50%); the use of the maximum energy efficiency principle in relay or domino systems may offer a good compromise for good system energy efficiency and transmission distance on the condition that relay resonators can be placed between the power source and the load.
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