2,3,4',5-Tetrahydroxystilbene-2-O-ß-d-glucoside attenuates atherosclerotic progression by inhibiting inflammation via downregulation of TNF receptor-associated factor 6 expression.

OBJECTIVE: Atherosclerosis (As) is an inflammatory disease, and 2,3,4',5-tetrahydroxystilbene-2-O-ß-d-glucoside (TSG) has been shown to suppress inflammation. However, it is still unclear if TSG alleviates As by inhibiting inflammation. MATERIALS AND METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to assess the mRNA levels of tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6), TNF-α and interleukin-6 (IL-6) in lipoprotein E knockout (ApoE -/-) mice with As. Hematoxylin-eosin (H&E) staining was performed to examine the atherosclerotic plaques in the aortic sinus. QRT-PCR and western blotting were used to measure the expression levels of TRAF6, TNF-α, and IL-6 in human umbilical vein endothelial cells (HUVECs), and enzyme-linked immunosorbent assays (ELISAs) were performed to monitor the levels of TNF-α and IL-6 in serum and cell culture medium. RESULTS: TSG inhibited subendothelial plaques formation in the aortic sinus and inhibited the levels of total cholesterol (TCHO), low-density lipoprotein (LDL), TRAF6, TNF-α and IL-6 in AS mice in a dose-dependent manner. Moreover, TSG attenuated the oxidatively modified LDL (ox-LDL)-induced increases in TRAF6, TNF-α and IL-6 expression, whereas TRAF6 overexpression reversed the TSG-induced decreases in TRAF6, TNF-α, and IL-6 expression in HUVECs. CONCLUSIONS: TSG attenuates atherosclerotic progression by inhibiting inflammation via the downregulation of TRAF6 in ApoE-/- mice and HUVECs.

Photoemission study of the electronic structure and charge density waves of Na2Ti2Sb2O.

The electronic structure of Na2Ti2Sb2O single crystal is studied by photon energy and polarization dependent angle-resolved photoemission spectroscopy (ARPES). The obtained band structure and Fermi surface agree well with the band structure calculation of Na2Ti2Sb2O in the non-magnetic state, which indicates that there is no magnetic order in Na2Ti2Sb2O and the electronic correlation is weak. Polarization dependent ARPES results suggest the multi-band and multi-orbital nature of Na2Ti2Sb2O. Photon energy dependent ARPES results suggest that the electronic structure of Na2Ti2Sb2O is rather two-dimensional. Moreover, we find a density wave energy gap forms below the transition temperature and reaches 65 meV at 7 K, indicating that Na2Ti2Sb2O is likely a weakly correlated CDW material in the strong electron-phonon interaction regime.

Angle-resolved photoemission spectroscopy study on the surface states of the correlated topological insulator YbB6.

YbB6 is recently predicted to be a moderately correlated topological insulator, which provides a playground to explore the interplay between correlation and topological properties. With angle-resolved photoemission spectroscopy, we directly observed almost linearly dispersive bands around the time-reversal invariant momenta and with negligible kz dependence, consistent with odd number of surface states crossing the Fermi level in a Z2 topological insulator. Circular dichroism photoemission spectra suggest that these in-gap states possess chirality of orbital angular momentum, which is related to the chiral spin texture, further indicative of their topological nature. The observed insulating gap of YbB6 is about 100 meV, larger than that found by theoretical calculations. Our results present strong evidence that YbB6 is a correlated topological insulator and provide a foundation for further studies of this promising material.

Electronic structure of Eu(Fe0.79Ru0.21)2As2 studied by angle-resolved photoemission spectroscopy.

Eu(Fe(0.79)Ru(0.21))2As2 is suggested to be a nodeless superconductor based on the empirical correlation between pnictogen height (hPn) and superconducting gap behavior, in contrast to BaFe2(As(0.7)P(0.3))2 and Ba(Fe(0.65)Ru(0.35))2As2. We studied the low-lying electronic structure of Eu(Fe(0.79)Ru(0.21))2As2 with angle-resolved photoemission spectroscopy (ARPES). By photon energy dependence and polarization dependence measurements, we resolved the band structure in the three-dimensional momentum space and determined the orbital character of each band. In particular, we found that the dz2 -originated ζ band does not contribute spectral weight to the Fermi surface around Z, unlike BaFe2(As(0.7)P(0.3))2 and Ba(Fe(0.65)Ru(0.35))2As2. Since BaFe2(As(0.7)P(0.3))2 and Ba(Fe(0.65)Ru(0.35))2As2 are nodal superconductors and their hPn's are less than 1.33 Å, while the hPn of Eu(Fe(0.79)Ru(0.21))2As2 is larger than 1.33 Å, our results provide more evidence for a direct relationship between nodes, dz2 orbital character and hPn. Our results help to provide an understanding of the nodal superconductivity in iron-based superconductors.

Observation of possible topological in-gap surface states in the Kondo insulator SmB6 by photoemission.

SmB6, a well-known Kondo insulator, exhibits a transport anomaly at low temperature. This anomaly is usually attributed to states within the hybridization gap. Recent theoretical work and transport measurements suggest that these in-gap states could be ascribed to topological surface states, which would make SmB6 the first realization of topological Kondo insulator. Here by performing angle-resolved photoemission spectroscopy experiments, we directly observe several dispersive states within the hybridization gap of SmB6. These states show negligible kz dependence, which indicates their surface origin. Furthermore, we perform photoemission circular dichroism experiments, which suggest that the in-gap states possess chirality of the orbital angular momentum. These states vanish simultaneously with the hybridization gap at around 150 K. Together, these observations suggest the possible topological origin of the in-gap states.

Nodeless superconducting gap in A(x)Fe2Se2 (A=K,Cs) revealed by angle-resolved photoemission spectroscopy.

Pairing symmetry is a fundamental property that characterizes a superconductor. For the iron-based high-temperature superconductors, an s(±)-wave pairing symmetry has received increasing experimental and theoretical support. More specifically, the superconducting order parameter is an isotropic s-wave type around a particular Fermi surface, but it has opposite signs between the hole Fermi surfaces at the zone centre and the electron Fermi surfaces at the zone corners. Here we report the low-energy electronic structure of the newly discovered superconductors, A(x)Fe(2)Se(2) (A=K,Cs) with a superconducting transition temperature (Tc) of about 30 K. We found A(x)Fe(2)Se(2) (A=K,Cs) is the most heavily electron-doped among all iron-based superconductors. Large electron Fermi surfaces are observed around the zone corners, with an almost isotropic superconducting gap of ~10.3 meV, whereas there is no hole Fermi surface near the zone centre, which demonstrates that interband scattering or Fermi surface nesting is not a necessary ingredient for the unconventional superconductivity in iron-based superconductors. Thus, the sign change in the s(±) pairing symmetry driven by the interband scattering as suggested in many weak coupling theories becomes conceptually irrelevant in describing the superconducting state here. A more conventional s-wave pairing is probably a better description.

Mutation analysis of the FLCN gene in Chinese patients with sporadic and familial isolated primary spontaneous pneumothorax.

Primary spontaneous pneumothorax (PSP) is a common manifestation of Birt-Hogg-Dubé syndrome caused by folliculin gene (FLCN) mutation, which is also found in isolated familial PSP cases. A complete genetic analysis of FLCN was performed in 102 unrelated Chinese patients with isolated PSP and 21 of their family members. Three novel mutations (c.924_926del, c.1611_1631del and c.1740C>T) and a previously reported mutation (c.1733insC) were identified in five familial and five sporadic PSP patients. Of the 21 family members of patients with PSP including 3 previous considered as sporadic, 4 (19%) had history of at least one episode of PSP and 9 (43%) were FLCN mutant carriers without PSP. Seven of the nine (78%) mutant carriers had pulmonary cysts detected by high-resolution computed tomography (HRCT). Although c.924_926del and c.1611_1631del were found in eight patients from the same geographic district, haplotype analysis demonstrated that they did not share the same affected haplotype, thus excluding common ancestry. This study first demonstrates that FLCN mutation contributes to not only familial but also 'apparently sporadic' patients with isolated PSP. It suggests that mutation analysis and HRCT scan may be recommended for first-degree family members of PSP patients with FLCN mutations, irrespective of their family history status of PSP.

Incomplete infarct and delayed neuronal death after transient middle cerebral artery occlusion in rats.

BACKGROUND AND PURPOSE: The clinical syndrome of transient ischemic attacks is accompanied in a significant percentage of patients by brain lesions or neuroimaging abnormalities whose structural counterparts have not been defined. The objective of this study was to analyze, in an experimental model of short-term (< 25 minutes) focal ischemia and long-term (< or = 28 days) reperfusion, the extent and nature of the structural abnormalities affecting neurons and glia located within the territory of the transiently occluded artery. METHODS: Adult Wistar rats (n = 121) had the origin of one middle cerebral artery (MCA) occluded with a nylon monofilament for periods of 10 to 25 minutes. Experiments of transient MCA occlusion were terminated at variable periods ranging from 1 day to 4 weeks. Control experiments consisted of (1) MCA occlusion without reperfusion (n = 7) lasting 7 to 14 days and (2) sham operations (n = 2) followed by 1- to 4-day survival. After in situ fixation, brain specimens were serially sectioned and subjected to detailed morphometric evaluations utilizing light and electron microscopes. The statistical method used to evaluate the results was based on ANOVA followed by Bonferroni's corrected t test and Student's t test comparisons. RESULTS: Brain lesions were not detectable in the sham-operated controls. All brains with permanent MCA occlusion (7 to 14 days) had large infarctions with abundant macrophage infiltration and early cavitation. Forty-five (37%) of the experiments involving transient MCA occlusion had no detectable brain lesions after 4 weeks. Selective neuronal necrosis was found in 76 of 121 rats (63%) with transient MCA occlusion. Neuronal necrosis always involved the striatum, and in 29% of the brains with ischemic injury, necrosis also included a short segment of the cortex. In the striatum, the length of the arterial occlusion was the main determinant of the number of necrotic neurons (20 minutes [22.6 +/- 19] is worse than 10 minutes [4.9 +/- 7]) (P < .0001). In the cortex, the length of reperfusion determined the number of necrotic neurons appearing in layer 3. Experiments with reperfusion of 4 to 7 days' duration yielded more necrotic neurons per microscopic field (2.02 +/- 3) than those lasting fewer days (0.04 +/- 0.1) (P < .05). The histological features of these lesions underwent continuous change until the end of the fourth week, at which time necrotic neurons were still visible both in the striatum and in the cortex. CONCLUSIONS: Arterial occlusions of short duration (< 25 minutes) produced, in 76 of 121 experiments (63%), brain lesions characterized by selective neuronal necrosis and various glial responses (or incomplete infarction). This lesion is entirely different from the pannecrosis/cavitation typical of an infarction that appears 3 to 4 days after a prolonged arterial occlusion. Delayed neuronal necrosis, secondary to a transient arterial occlusion or increasing numbers of necrotic neurons in experiments with variable periods of reperfusion, was a response observed only at a predictable segment of the frontoparietal cortex.

Glial fibrillary acidic protein immunohistochemical study of Alzheimer I & II astrogliosis in Wilson's disease.

This study compared the relationships of the development of both Alzheimer I & II cells to reactive astrogliosis and also their distributional patterns in the demyelinated and non-demyelinated lesions in 6 cases of Wilson's disease by the use of PAP immunohistochemical technique for glial fibrillary acidic protein (GFAP). The development of GFAP positive Alzheimer I (A-I) cells was found to be directly proportional to the capability of reactive astrogliosis, and inversely proportional to the severity of Alzheimer II (A-II) change. The GFAP negative A-II cells could be identified morphologically into 2 subtypes: one with well-developed nuclei, the other with "shrunken" nuclei. They were believed to stand for the "compensatory" and "decompensatory" stages of this dynamic astrogliotic process respectively. The distribution patterns of these 2 types of astrogliosis were different: A-I cells were found only in the regions of demyelination with intensive reactive astrogliosis, while A-II cells were found diffusely in both the grey and white matter, affecting both the protoplasmic and fibrous astrocytes without special predilection.