Modulation of the absorption coefficient at 1.3 μm in Ge/SiGe multiple quantum well heterostructures on silicon

We report modulation of the absorption coefficient at 1.3 μm in Ge/SiGe multiple quantum well heterostructures on silicon via the quantum-confined Stark effect. Strain engineering was exploited to increase the direct optical bandgap in the Ge quantum wells. We grew 9 nm-thick Ge quantum wells on a relaxed Si0.22Ge0.78 buffer and a contrast in the absorption coefficient of a factor of greater than 3.2 was achieved in the spectral range 1290-1315 nm.

Galectin-9 protein expression in endothelial cells is positively regulated by histone deacetylase 3

Galectin-9 expression in endothelial cells can be induced in response to inflammation. However, the mechanism of its expression remains unclear. In this study, we found that interferon-γ (IFN-γ) induced galectin-9 expression in human endothelial cells in a time-dependent manner, which coincided with the activation of histone deacetylase (HDAC). When endothelial cells were treated with the HDAC3 inhibitor, apicidin, or shRNA-HDAC3 knockdown, IFN-γ-induced galectin-9 expression was abolished. Overexpression of HDAC3 induced the interaction between phosphoinositol 3-kinase (PI3K) and IFN response factor 3 (IRF3), leading to IRF3 phosphorylation, nuclear translocation, and galectin-9 expression. HDAC3 functioned as a scaffold protein for PI3K/IRF3 interaction. In addition to galectin-9 expression, IFN-γ also induced galectin-9 location onto plasma membrane, which was HDAC3-independent. Importantly, HDAC3 was essential for the constitutive transcription of PI3K and IRF3, which might be responsible for the basal level of galectin-9 expression. The phosphorylation of IRF3 was essential for galectin-9 expression. This study provides new evidence that HDAC3 regulates galectin-9 expression in endothelial cells via interaction with PI3K-IRF3 signal pathway.

Immunoregulation effect by overexpression of heme oxygenase-1 on cardiac xenotransplantation

OBJECTIVE

This study was designed to investigate the effect of the overexpression of heme oxygenase-1 (HO-1) on the immunoregulation in the model of abdominal cardiac xenotransplantation from the guinea pig to the rat.

MATERIALS AND METHODS

To increase the expression of HO-1, both donors and recipients were injected with heme through the abdomen before the operation. The donors (guniea pigs) and the recipients (Sprague-Dawley [SD] rats) were divided randomly into three groups: group A, the heart from a guinea pig transplanted into the abdomen of an SD rat; group B, the recipients were injected with Chinese cobra venom factor (CVF) into the abdomen (40 μg/kg and 60 μg/kg 24 hours later) prior to transplantation; group C, CVF + HO-1 high-expression group: donors and recipients were abdominally injected with heme (75 μmol/kg for 2 days before transplantation). The mean survival time (MST), pathological changes, the positive area of HO-1 in the grafted hearts, as well as the expressions of C-C chemokine receptor 5 (CCR5), intercellular adhesion molecule-1 (ICAM-1), and natural killer (NK) cell activity in recipients.

RESULTS

1. The MST was longest in group C treated with heme. 2. The pathologic changes of hyperacute rejection were showed on the donor heart in group A, while delayed xenograft rejection changes took place on donor heart in other groups. 3. Compared with group B, The HO-1 positive area in the donor hearts of group C was significantly higher. (P < .05). 4. The lever of ICAM-1 and CCR5 in the peripheral blood of recipients (pg/mL) was attenuated in group C injected with heme. 5. Compared with group B, the activity of NK cell in the peripheral blood of recipients was much lower in group C (P < .05).

CONCLUSION

The MST was prolonged by increasing expressions of HO-1, but acute vascular rejection was not completely overcome. Activation of vascular endothelial cells could be decreased by strengthening the expression of HO-1. NK cell activity was weakened by reinforced expression of HO-1.

Microarray analysis of gene expression changes in the brains of NR2B-induced memory-enhanced mice

Glutamate N-methyl-D-aspartate (NMDA) receptors play a pivotal role in different forms of memory. The dysfunction of NMDA receptors contributes to the pathology of central nervous system (CNS) disorders. To further investigate the role of the NMDA receptors in brain processes, we analyzed and compared the gene expression profiles in the hippocampus of NR2B overexpression-induced memory-enhanced mice (Tg mice) with those of their wild-type littermates. Results reveal that 249 genes, which are mainly involved in neurotransmission, signal transduction, cytoskeletal structure, hormone activity, and transcription, were significantly affected in Tg mice. Interestingly, the intracellular calcium channel proteins ryanodine receptor (RyR) 1 and 3, as well as functionally related proteins such as the histidine-rich calcium-binding protein and triadin 2, were upregulated. The Homer-1c protein was also increased in Tg mice and formed a complex with the RyR protein in the mouse brain, suggesting that Homer-1c is an important modulator in both intracellular calcium signaling and overall neuronal signaling by simultaneously interacting with the NMDA receptors and RyR. Western blot and real-time PCR results show that the expression of phospho-CREB, c-fos, and the immediate-early genes Egr2 and Egr4 were also upregulated in Tg mice. The current study demonstrates that a chronic increase in the activation of NMDA receptors affected the expression of a large number of genes and may provide important clues for a better understanding of the molecular mechanism of NMDA receptor-modulated learning and memory, as well as of CNS disorders.

Taking into account latency, amplitude, and morphology: improved estimation of single-trial ERPs by wavelet filtering and multiple linear regression

Across-trial averaging is a widely used approach to enhance the signal-to-noise ratio (SNR) of event-related potentials (ERPs). However, across-trial variability of ERP latency and amplitude may contain physiologically relevant information that is lost by across-trial averaging. Hence, we aimed to develop a novel method that uses 1) wavelet filtering (WF) to enhance the SNR of ERPs and 2) a multiple linear regression with a dispersion term (MLR(d)) that takes into account shape distortions to estimate the single-trial latency and amplitude of ERP peaks. Using simulated ERP data sets containing different levels of noise, we provide evidence that, compared with other approaches, the proposed WF+MLR(d) method yields the most accurate estimate of single-trial ERP features. When applied to a real laser-evoked potential data set, the WF+MLR(d) approach provides reliable estimation of single-trial latency, amplitude, and morphology of ERPs and thereby allows performing meaningful correlations at single-trial level. We obtained three main findings. First, WF significantly enhances the SNR of single-trial ERPs. Second, MLR(d) effectively captures and measures the variability in the morphology of single-trial ERPs, thus providing an accurate and unbiased estimate of their peak latency and amplitude. Third, intensity of pain perception significantly correlates with the single-trial estimates of N2 and P2 amplitude. These results indicate that WF+MLR(d) can be used to explore the dynamics between different ERP features, behavioral variables, and other neuroimaging measures of brain activity, thus providing new insights into the functional significance of the different brain processes underlying the brain responses to sensory stimuli.

The primary somatosensory cortex largely contributes to the early part of the cortical response elicited by nociceptive stimuli

Research on the cortical sources of nociceptive laser-evoked brain potentials (LEPs) began almost two decades ago (Tarkka and Treede, 1993). Whereas there is a large consensus on the sources of the late part of the LEP waveform (N2 and P2 waves), the relative contribution of the primary somatosensory cortex (S1) to the early part of the LEP waveform (N1 wave) is still debated. To address this issue we recorded LEPs elicited by the stimulation of four limbs in a large population (n=35). Early LEP generators were estimated both at single-subject and group level, using three different approaches: distributed source analysis, dipolar source modeling, and probabilistic independent component analysis (ICA). We show that the scalp distribution of the earliest LEP response to hand stimulation was maximal over the central-parietal electrodes contralateral to the stimulated side, while that of the earliest LEP response to foot stimulation was maximal over the central-parietal midline electrodes. Crucially, all three approaches indicated hand and foot S1 areas as generators of the earliest LEP response. Altogether, these findings indicate that the earliest part of the scalp response elicited by a selective nociceptive stimulus is largely explained by activity in the contralateral S1, with negligible contribution from the secondary somatosensory cortex (S2).

Adventitial biology: differentiation and function

Recent evidence indicates that stem/progenitor cells are present in the adventitia and participate in vascular repair and the formation of neointimal lesions in severely damaged vessels. Data have also demonstrated that these resident stem/progenitor cells could differentiate into endothelial or smooth muscle cells in response to different stimuli. Under pathological conditions, adventitial inflammation results in releasing a panel of cytokines, such as stromal cell-derived factor-1 and tumor necrosis factor-α, that may lead to local stem/progenitor mobilization and differentiation. Overall, these data support the impact of the adventitial progenitors in pathophysiological processes of lesion development in the arterial wall. In the present review, we aim to summarize the data concerning the presence of the resident stem cells and discuss the pathological impact of the adventitia in vascular diseases. We will also discuss the possible signal pathways orchestrating stem cell differentiation toward vascular lineage and highlight controversial issues related to the role of adventitial progenitors.

Correlation between expression of cadherin and gap junctional communication in human lung carcinoma cells

The correlation between expression of ca(2+)-dependent cell adhesion molecule, cadherin, and gap junctional intercellular communication (GJIC) in human lung carcinoma PG cell line and connexin43 (Cx43) cDNA transfected PG cell clones was investigated. Results from immunoblotting and immunofluorescent staining revealed that cultured normal human lung cells (RF) expressed N-cadherin. However, the expression level of Kcadherin in PG cells was very low in comparison with normal RF cells. The Cx43 transfected PG clones exhibited comparable levels of Cx43 protein, but varied in the level of N-cadherin expression and in the function of GJIC as measured by scrape-loading and dye transfer (SLDT) method. Positive correlation between N-cadherin and GJIC was demonstrated. Thein vitro andin uivo, growth examination results suggest that N-cadherin mediated cell-cell adhesions and Cx43 functional expression, the GJIC, may work coordinately with each other in regulation of cell growth and differentiation. Deficiency in both GJIC and cell adhesion may be crucial for cell transformation.

Proteome analysis of wheat leaf under salt stress by two-dimensional difference gel electrophoresis (2D-DIGE)

Salt stress is a major abiotic stress that limits agricultural productivity in many regions of the world. To understand the molecular basis of the salt stress response in wheat (Triticum aestivum L.), a proteomic approach was used to identify the salt stress-responsive proteins in an elite Chinese wheat cultivar, Zhengmai 9023, which exhibits a high yield, superior gluten quality and better biotic resistance. Three-week-old seedlings were treated with NaCl of four different concentrations (1.0%, 1.5%, 2.0%, and 2.5%). The total proteins from the leaves of untreated and NaCl-treated plants were extracted and separated by two-dimensional difference gel electrophoresis (2D-DIGE). A total of 2358 protein spots were detected on the gels, among which 125 spots showed a significant change in protein abundance, and 83 differentially expressed spots were localised on preparative gels. Using Q-TOF mass spectrometry, 52 salt-responsive spots were identified, which were classified into six functional categories that included transport-associated proteins, detoxifying enzymes, ATP synthase, carbon metabolism, protein folding, and proteins with unknown biological functions. Of the 52 differentially expressed proteins, 26 were up-regulated, 21 were down-regulated, and five spots showed multi-expression patterns. In particular, some important proteins for salt tolerance were found to be up-regulated in Zhengmai 9023 under salt stress, such as H(+)-ATPases, glutathione S-transferase, ferritin and triosephosphate isomerase.