Giant phonon softening and enhancement of superconductivity by phosphorus doping of BaNi2As2

The effects of phosphorus doping on the structural and superconducting phase transitions of BaNi2(As(1-x)P(x))2 were studied. The specific heat, resistivity, and magnetic susceptibility were measured. The results revealed an abrupt increase in the superconducting transition temperature (T(c)) from 0.6 K in the triclinic phase (space group P1¯) with less phosphorus (x≤0.067) to 3.3 K in the tetragonal phase (space group I4/mmm) with more phosphorus (x≥0.067). Our data analysis suggests that a doping-induced softening related to an in-plane Ni and As(P) phonon mode is responsible for the enhanced superconductivity in the tetragonal phase.

Prediction of carotid plaque characteristics using non-gated MR imaging: correlation with endarterectomy specimens

BACKGROUND AND PURPOSE

Electrocardiographic gating, commonly used in MR carotid plaque imaging, can negatively affect intraplaque contrast if the TR is inappropriate. The present study aimed to determine whether a non-gated technique with appropriate TRs can accurately evaluate intraplaque characteristics in specimens excised by CEA.

MATERIALS AND METHODS

We prospectively examined 40 consecutive patients who underwent CEA (59-82 years of age) by using a 1.5T scanner. Axial T1WI with a TR of 500 ms and PDWI and T2WI with a TR of 3000 ms with a self-navigated rotating-blade scan instead of cardiac gating were obtained. Signal intensities of the plaque and adjacent muscle were measured, and the CR on T1WI, PDWI, and T2WI as well as the gray-scale median on US were correlated with the pathologic findings of the CEA specimens.

RESULTS

On T1WI, the CRs of the carotid plaques differed significantly among groups in which the main components were histologically confirmed as fibrous tissue, lipid/necrosis, and hemorrhage (0.54-1.17, 1.16-1.53, and 1.40-2.29, respectively). The sensitivity and specificity for discriminating lipid/necrosis/hemorrhage from fibrous tissue were 96% and 100%, respectively. On T2WI, the CRs of plaques with lipid/necrosis were significantly higher than those of other groups, but the CRs on PDWI and the gray-scale median on US were not significantly different among the groups.

CONCLUSIONS

Non-gated MR plaque imaging, particularly T1WI, can readily predict the intraplaque main components of the carotid artery with high sensitivity and specificity.

Cysteine, histidine and glycine exhibit anti-inflammatory effects in human coronary arterial endothelial cells

The activation of nuclear factor-kappa B (NF-κB) in vascular endothelial cells may be involved in vascular pathogeneses such as vasculitis or atherosclerosis. Recently, it has been reported that some amino acids exhibit anti-inflammatory effects. We investigated the inhibitory effects of a panel of amino acids on cytokine production or expression of adhesion molecules that are involved in inflammatory diseases in various cell types. The activation of NF-κB was determined in human coronary arterial endothelial cells (HCAECs) because NF-κB modulates the production of many cytokines and the expression of adhesion molecules. We examined the inhibitory effects of the amino acids cysteine, histidine and glycine on the induction of NF-κB activation, expression of CD62E (E-selectin) and the production of interleukin (IL)-6 in HCAECs stimulated with tumour necrosis factor (TNF)-α. Cysteine, histidine and glycine significantly reduced NF-κB activation and inhibitor κBα (IκBα) degradation in HCAECs stimulated with TNF-α. Additionally, all the amino acids inhibited the expression of E-selectin and the production of IL-6 in HCAECs, and the effects of cysteine were the most significant. Our results show that glycine, histidine and cysteine can inhibit NF-κB activation, IκBα degradation, CD62E expression and IL-6 production in HCAECs, suggesting that these amino acids may exhibit anti-inflammatory effects during endothelial inflammation.

Inhibition of Gli1 results in altered c-Jun activation, inhibition of cisplatin-induced upregulation of ERCC1, XPD and XRCC1, and inhibition of platinum-DNA adduct repair

The transcription of ERCC1 and other nucleotide excision repair (NER) genes is strongly influenced by c-jun. C-jun is transcriptionally regulated by Gli proteins of the Hedgehog pathway. We therefore studied the possible relationships between Gli1, c-jun, and the upregulation of ERCC1, XPD and XRCC1 in cisplatin-resistant human ovarian cancer cells. We studied the paired human ovarian cancer cell lines A2780 and A2780-CP70. We used a shRNA construct that specifically degrades Gli1 message. Genes we assessed for mRNA and/or protein levels included: c-jun, ERCC1, XPD, XRCC1, Gli1, Gli2, SHH, IHH, GAPDH and α-tubulin. Platinum-DNA adduct repair was assessed by atomic absorbance spectrometry with Zeeman background correction. Use of the anti-Gli1 shRNA in cisplatin-resistant cells resulted in a block of the cell's ability to upregulate genes in response to cisplatin treatment, including: c-jun, ERCC1, XPD and XRCC1. This block in upregulation of c-jun was concurrent with a change in the phosphorylation pattern of the c-jun protein, shifting that pattern from a Ser63/73 dominant pattern, to a Thr91/93 dominant pattern. A2780-CP70 cells were treated at their cisplatin IC50, and DNA repair was assessed after pretreatment with anti-Gli1 shRNA or scrambled shRNA control. Control cells repaired 78% of platinum-DNA adducts at 12 h, compared with 33% repair in cells pretreated with anti-Gli1 shRNA resulting in a 2.4-fold difference. Pretreatment of A2780-CP70 cells with anti-Gli1 shRNA resulted in supra-additive cell killing with cisplatin; shifting the cisplatin IC50 (half maximal inhibitory concentration) from 30 μM to 5 μM. Pretreatment of these cells with cyclopamine did not shift the cisplatin IC50. We conclude that the transcriptional protein Gli1 is important in the upregulation of these three DNA repair genes in human ovarian cancer cells, and that Gli1 strongly influences platinum-DNA adduct repair, and cellular sensitivity to cisplatin. This Gli1 role has c-jun as an intermediate in the pathway. In all, inhibition of Gli1 by a specific shRNA inhibits the upregulation of c-jun Ser63/73, and also inhibits the upregulation of three genes essential to NER (ERCC1, XPD) and base excision repair (XRCC1).

Activin A inhibits vascular endothelial cell growth and suppresses tumour angiogenesis in gastric cancer

Background:

Activin A is a multi-functional cytokine belonging to the transforming growth factor-β (TGF-β) superfamily; however, the effect of activin A on angiogenesis remains largely unclear. We found that inhibin β A subunit (INHBA) mRNA is overexpressed in gastric cancer (GC) specimens and investigated the effect of activin A, a homodimer of INHBA, on angiogenesis in GC.

Methods:

Anti-angiogenic effects of activin A via p21 induction were evaluated using human umbilical vein endothelial cells (HUVECs) in vitro and a stable INHBA-introduced GC cell line in vivo.

Results:

Compared with TGF-β, activin A potently inhibited the cellular proliferation and tube formation of HUVECs with induction of p21. A promoter assay and a chromatin immunoprecipitation assay revealed that activin A directly regulates p21 transcriptional activity through Smads. Stable p21-knockdown significantly enhanced the cellular proliferation of HUVECs. Notably, stable p21-knockdown exhibited a resistance to activin-mediated growth inhibition in HUVECs, indicating that p21 induction has a key role on activin A-mediated growth inhibition in vascular endothelial cells. Finally, a stable INHBA-introduced GC cell line exhibited a decrease in tumour growth and angiogenesis in vivo.

Conclusion:

Our findings highlight the suppressive role of activin A, unlike TGF-β, on tumour growth and angiogenesis in GC.