Using neutral beams as a light ion beam probe (invited)

By arranging the particle first banana orbits to pass near a distant detector, the light ion beam probe (LIBP) utilizes orbital deflection to probe internal fields and field fluctuations. The LIBP technique takes advantage of (1) the in situ, known source of fast ions created by beam-injected neutral particles that naturally ionize near the plasma edge and (2) various commonly available diagnostics as its detector. These born trapped particles can traverse the plasma core on their inner banana leg before returning to the plasma edge. Orbital displacements (the forces on fast ions) caused by internal instabilities or edge perturbing fields appear as modulated signal at an edge detector. Adjustments in the q-profile and plasma shape that determine the first orbit, as well as the relative position of the source and detector, enable studies under a wide variety of plasma conditions. This diagnostic technique can be used to probe the impact on fast ions of various instabilities, e.g., Alfvén eigenmodes (AEs) and neoclassical tearing modes, and of externally imposed 3D fields, e.g., magnetic perturbations. To date, displacements by AEs and by externally applied resonant magnetic perturbation fields have been measured using a fast ion loss detector. Comparisons with simulations are shown. In addition, nonlinear interactions between fast ions and independent AE waves are revealed by this technique.

β-Catenin is required for maintaining hippocampal morphology during the perinatal period

In mice, the compact hippocampal primordium is formed during the prenatal stage by early-generated neurons that migrate from the lateral ventricular zone. However, despite much being understood about the formation of the hippocampus, the molecular mechanisms that maintain the morphology of the hippocampal primordium after its formation remain to be characterized. β-Catenin is a key factor of canonical Wnt signaling and also a component of adherens junctions. Previous embryonic deletion studies have demonstrated that β-catenin is required for early development and generation of granule cells. However, whether β-catenin is involved in the morphological maintenance of the hippocampus as a cell adhesion molecule is still unknown. Here, we report that perinatal deletion of β-catenin in postmitotic neurons and some radial glial cells of hippocampus using CamKIIα-iCre; β-cateninflox/flox conditional knockout mice, leads to disorganization of the radial glial scaffold and consequentially severe defects in hippocampal morphology. We demonstrate that β-catenin is required for maintaining radial glial scaffold possibly via its well-known role in cell adhesion during the perinatal period. These findings provide essential advances into our understanding of the maintenance of the hippocampal primordium during the perinatal period.

Identification of 32 major histocompatibility complex class I alleles in African green monkeys

The African green monkey may be an ideal replacement for the rhesus monkey in biomedical research, but relatively little is known about the genetic background of major histocompatibility complex (MHC) class I molecules. In analysis of 12 African green monkeys, 13 Chae-A and 19 Chae-B alleles were identified. Among these alleles, 12 Chae-A and 9 Chae-B were new lineages. The full amino acid length deduced for Chae-A genes is 365 amino acids, but for Chae-B genes, the lengths are 365, 362, 361, and 359 amino acids, respectively. There were 1-3 Chae-A alleles and 2-5 Chae-B alleles in each animal. In African green monkeys, rhesus monkeys, and cynomolgus monkeys, the MHC-A and MHC-B alleles display trans-species polymorphism, rather than being clustered in a species-specific fashion.

Seven novel MHC class I alleles identified in Cercopithecus mitis

We report here the identification of three Cemi-A and four Cemi-B novel alleles of Cercopithecus mitis.

Evidence for Borna disease virus infection in neuropsychiatric patients in three western China provinces

Borna disease virus (BDV) is a non-cytolytic, neurotropic RNA virus that can infect a wide variety of vertebrate species from birds and primates to humans. Several studies have been carried out to investigate whether BDV is associated with neuropsychiatric diseases. However, this association is still inconclusive. Two panels of subjects consisting of 1,679 various neuropsychiatric patients and healthy people from three western China provinces were enrolled in this study. BDV p24 or p40 RNA in peripheral blood mononuclear cells (PBMCs) were detected in the first panel of 1,481 subjects using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and cerebrospinal fluid (CSF) samples from the BDV RNA-positive individuals were subjected to BDV p24 antibodies testing by enzyme-linked immunosorbent assay (ELISA). BDV p24 or p40 RNA in PBMCs and p24 antibodies in plasma were detected in the second panel of 198 subjects by RT-qPCR and Western blot. A higher prevalence for BDV RNA was demonstrated in patients with viral encephalitis (6.70%), Guillain-Barré syndrome (6.70%), schizophrenia (9.90%) and chronic fatigue syndrome (CFS) (12.70%) compared to healthy controls in the first panel. CSF p24 antibodies were demonstrated in three viral encephalitis patients, two schizophrenia patients and two major depressive disorder (MDD) patients. The prevalences of p24 antibodies in plasma from patients with viral encephalitis (13.24%), multiple sclerosis (25.00%) and Parkinson's disease (22.73%) were significantly higher than healthy controls. This study demonstrates that BDV infection also exists in humans from three western China provinces, and suggests the involvement of the contribution of BDV in the aetiology of Chinese patients with some neuropsychiatric disorders, including viral encephalitis, schizophrenia, CFS, multiple sclerosis and Parkinson's disease.

Hyperglycaemia-induced chemoresistance of prostate cancer cells due to IGFBP2

Clinically relevant prostate cancer (PCa) is more frequent in Westernised societies and increasingly men have co-morbidities associated with a Western lifestyle, primarily diabetes, characterised by hyperinsulinaemia and hyperglycaemia. IGFs and their binding proteins (IGFBPs) are important mediators of the effects of nutrition on growth and play a key role in the development of PCa. We used DU145, PC3 and LNCaP PCa cell lines to examine how hyperglycaemia altered their response to docetaxel. Trypan Blue dye-exclusion assay was used to determine the percentage of cell death. Protein abundance was determined using western immunoblotting. Levels of IGFBP2 were measured using an ELISA. IGFBP2 gene silencing was achieved using siRNA technology. DNA methylation was assessed using combined bisulphide restriction analysis. Acetylation status of histones H3 and H4 associated with IGFBP2 gene was assessed using chromatin immunoprecipitation assay. Hyperglycaemia reduced docetaxel-induced apoptosis by 40% for DU145 cells and by 88% for LNCaP cells. This reduced cell death was mediated by a glucose-induced up-regulation of IGFBP2, as silencing IGFBP2 negated the survival effect of high glucose. Glucose increased IGFBP2 via increasing the acetylation of histones associated with the IGFBP2 gene promoter. This finding could have important implications in relation to therapeutic strategies as epigenetic modulation could be reversible.

Nucleotide receptor P2RX7 stimulation enhances LPS-induced interferon-β production in murine macrophages

Stimulation of P2RX(7) with extracellular ATP potentiates numerous LPS-induced proinflammatory events, including cytokine induction in macrophages, but the molecular mechanisms underlying this process are not well defined. Although P2RX(7) ligation has been proposed to activate several transcription factors, many of the LPS-induced mediators affected by P2RX(7) activation are not induced by P2RX(7) agonists alone, suggesting a complementary role for P2RX(7) in transcriptional regulation. Type I IFN production, whose expression is tightly controlled by multiple transcription factors that form an enhanceosome, is critical for resistance against LPS-containing bacteria. The effect of purinergic receptor signaling on LPS-dependent type I IFN is unknown and would be of great relevance to a diverse array of inflammatory conditions. The present study demonstrates that stimulation of macrophages with P2RX(7) agonists substantially enhances LPS-induced IFN-β expression, and this enhancement is ablated in macrophages that do not express functional P2RX(7) or when the MAPK MEK1/2 pathways are inhibited. Potentiation of LPS-induced IFN-β expression following P2RX(7) stimulation is likely transcriptionally regulated, as this enhancement is observed at the IFN-β promoter level. Furthermore, P2RX(7) stimulation is able to increase the phosphorylation and subsequent IFN-β promoter occupancy of IRF-3, a transcription factor that is critical for IFN-β transcription by TLR agonists. This newly discovered role for P2RX(7) in IFN regulation may have implications in antimicrobial defense, which has been linked to P2RX(7) activation in other studies.

Establishment, characterization and viral susceptibility of two cell lines derived from leopard wrasse Macropharyngodon geoffroy

Two new fish cell lines were established from skin (LWSK) and fin (LWFN) of leopard wrasse Macropharyngodon geoffroy. These cells grew optimally at 25° C in Leibovitz-15 medium supplemented with 10% foetal bovine serum. Proliferation of M. geoffroy cells remained serum dependent up to cell passage 16, and cell-plating efficiency ranged from 12 to 16%. Karyotypic analysis of these new cell lines at cell passage 8 indicated that both cell lines remained diploid with a peak chromosomal count of 144. PCR amplification of 16S mitochondrial DNA and the subsequent analysis confirmed that these cell lines were indeed derived from M. geoffroy. Results of viral challenge assays revealed that both LWSK and LWFN shared patterns of viral susceptibility similar to that of six fish viruses tested: LWSK and LWFN cells were highly permissive to channel catfish virus, spring viremia carp virus and snakehead rhabdovirus with high-yield virus production ranging from 10(7·18±0·17) to 10(8·37±0·16) TCID50  ml(-1) (mean ± s.d.). These newly established cell lines would be useful in attempts to isolate and study aquatic viruses, particularly the viral aetiology of green turtle fibropapilloma as M. geoffroy is known to be one of the common cleaner fish of green sea turtles.

Bone marrow-derived endothelial progenitor cells promote hematopoietic reconstitution after hematopoietic stem cell transplantation

OBJECTIVE

A hematopoietic deficit is a serious complication after hematopoietic stem cell transplantation. It has been shown that fetal blood-derived endothelial progenitor cells (EPCs) can promote hematopoietic reconstitution after transplantation. This study investigated whether EPCs from bone marrow (BM) of adult mice could promote hematopoietic reconstitution.

METHODS

Lethally irradiated BALB/c mice were administered BM cells or BM cells plus EPCs.

RESULTS

The results showed that EPC-treated mice displayed accelerated recovery of peripheral blood white blood cells and reticulocytes. But the platelets were not significantly different with versus without EPCs. Accelerated recovery of BM sinusoidal vessels, promotion of stem cell implantation, and decreased adipocyte formation were associated with the mechanism. Systemic administration of anti-vascular endothelial cadherin antibody neutralized these effects significantly.

CONCLUSION

These data showed that BM-derived EPC infusions augmented hematopoiesis suggesting a new approach to promote hematopoiesis.

A rotating directional probe for the measurements of fast ion losses and plasma rotation at Tokamak Experiment for Technology Oriented Research

This work discusses a new directional probe designed for measurements of fast ion losses and the plasma rotation with a high angular resolution in magnetically confined plasmas. Directional and especially Mach probes are commonly used diagnostics for plasma flow measurements, and their applicability for the fast ion losses detection has been demonstrated. A limitation of static Mach probes is their low angular resolution. At the Tokamak Experiment for Technology Oriented Research, the angular resolution is strongly restricted by the finite number of available measurement channels. In a dynamic plasma, where instabilities can lead to local changes of the field line pitch-angle, plasma flow, or fast ion losses, a low angular resolution makes a precise data analysis difficult and reduces the quality of the measured data. The new probe design, the rotating directional probe, combines the features of early directional probes and Mach probes. It consists of two radially aligned arrays of nine Langmuir probe pins with each array facing opposite directions. During the measurement the probe head rotates along its axis to measure the ion saturation current from all directions. As a result, the rotating directional probe simultaneously provides an angular dependent plasma flow and fast ion losses measurement at different radial positions. Based on the angular dependent data, a precise determination of the current density is made. In addition, the simultaneous measurement of the ion saturation current at different radial positions allows for resolving radially varying field line pitch-angles and identifying the radial dynamic of processes like fast ion losses.

The GSTP1 A1578G polymorphism and the risk of childhood acute lymphoblastic leukemia: results from an updated meta-analysis

Studies investigating the association between the glutathione S-transferase P1 (GSTP1) A1578G polymorphism and the risk of childhood acute lymphoblastic leukemia (ALL) report conflicting results. The aim of this study was to quantitatively summarize the evidence for such a relationship. Two investigators independently searched the Medline, Embase, China National Knowledge Infrastructure, and Wangfang databases for studies of the polymorphism and ALL. Summary odds ratios (ORs) and 95% confidence intervals (CIs) for the GSTP1 polymorphism and childhood ALL were calculated in a fixed-effect model. Pooled ORs were calculated for a co-dominant model (GG vs AA, AG vs AA), a dominant model (GG + AG vs AA), and a recessive model (GG vs AA + AG). Analyses were also performed in subgroups stratified by race, study design, genotyping methods, and study sample size. This meta-analysis included 8 case-control studies with 1384 childhood ALL cases and 1755 controls. Overall, the variant genotypes (GG and AG) of A1578G were not associated with childhood ALL risk, when compared with the wild-type homozygote AA genotype (GG vs AA, OR = 1.09, 95%CI = 0.84-1.43; AG vs AA, OR = 1.05, 95%CI = 0.91-1.23). Similarly, no associations were found in the dominant and recessive models (dominant model, OR = 1.06, 95%CI = 0.92-1.23; recessive model, OR = 1.09, 95%CI = 0.84-1.43). Stratified analyses did not detect significant association in any subgroup. No heterogeneity or publication bias was observed in the present study. This updated meta-analysis indicates that the GSTP1 A1578G polymorphism is not associated with the risk of childhood ALL. In the future, additional studies in Asian and African-American patients should be performed to re-evaluate the association in these populations.

Muscle cell-derived factors inhibit inflammatory stimuli-induced damage in hMSC-derived chondrocytes

OBJECTIVE

Pro-inflammatory cytokines play an important role in inducing cartilage degradation during osteoarthritis pathogenesis. Muscle is a tissue that lies near cartilage in situ. However, muscle's non-loading biochemical effect on cartilage has been largely unexplored. Here, we tested the hypothesis that muscle cells can regulate the response to pro-inflammatory cytokine-mediated damage in chondrocytes derived from human bone marrow-derived mesenchymal stem cells (hMSCs).

METHOD

hMSCs were allowed to undergo chondrogenic differentiation in porous silk scaffolds in the typical chondrogenic medium for 12 days. For the next 9 days, the cells were cultured in chondrogenic medium containing 50% conditioned medium derived from C2C12 muscle cells or fibroblast control cells, and were subject to treatments of pro-inflammatory cytokines IL-1β or TNFα.

RESULTS

Both IL-1β and TNFα-induced strong expression of multiple MMPs and hypertrophic markers Runx2 and type X collagen. Strikingly, culturing hMSC-derived chondrocytes in C2C12 muscle cell-conditioned medium strongly inhibited the expression of all these genes, a result further confirmed by GAG content and histological evaluation of matrix protein. To determine whether these effects were due to altered chondrocyte growth and survival, we assayed the expression of cell proliferation marker Ki67, cell cycle arrest markers p21 and p53, and apoptosis marker caspase 3. Muscle cell-conditioned medium promoted proliferation and inhibited apoptosis, thereby suggesting a possible decrease in the cellular aging and death that typically accompanies cartilage inflammation.

CONCLUSION

Our findings suggest the role of muscle in cartilage homeostasis and provide insight into designing strategies for promoting resistance to pro-inflammatory cytokines in hMSC-derived chondrocytes.

Experimental observation of a magnetic-turbulence threshold for runaway-electron generation in the TEXTOR tokamak

Magnetic turbulence is observed at the beginning of the current quench in intended TEXTOR disruptions. Runaway electron (RE) suppression has been experimentally found at magnetic turbulence larger than a certain threshold. Below this threshold, the generated RE current is inversely proportional to the level of magnetic turbulence. The magnetic turbulence originates from the background plasma and the amplitude depends strongly on the toroidal magnetic field and plasma electron density. These results explain the previously found toroidal field threshold for RE generation and have to be considered in predictions for RE generation in ITER.

Magnetic topology changes induced by lower hybrid waves and their profound effect on edge-localized modes in the EAST tokamak

Strong mitigation of edge-localized modes has been observed on Experimental Advanced Superconducting Tokamak, when lower hybrid waves (LHWs) are applied to H-mode plasmas with ion cyclotron resonant heating. This has been demonstrated to be due to the formation of helical current filaments flowing along field lines in the scrape-off layer induced by LHW. This leads to the splitting of the outer divertor strike points during LHWs similar to previous observations with resonant magnetic perturbations. The change in the magnetic topology has been qualitatively modeled by considering helical current filaments in a field-line-tracing code.

Incidence of skeletal-related events over time from solid tumour bone metastases reported in randomised trials using bone-modifying agents

AIMS

Skeletal-related events (SREs) in patients with bone metastases decrease a patient's quality of life and functional status. Although bone-modifying agents have been found to reduce the time to first on-trial SRE and decrease the total incidence of SREs in randomised clinical trials, standard practice in the management of bone metastases has changed concurrently. The purpose of this study was to investigate if advances in bone-targeted therapies have decreased the incidence of individual types of SREs and to delineate the trend of SREs.

MATERIALS AND METHODS

A literature review was conducted in MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials to identify phase III, randomised bisphosphonate and other bone-targeted therapy trials from 1980 to September 2011. For all studies, a mean year of enrolment ([start of enrolment + end of enrolment]/2) was calculated. The incidences of SREs were tabulated and expressed as percentages of on-trial patients. Generalised linear mixed models were used to search for the trends of SREs over time for all placebo and intervention arms. Regression coefficients were interpreted as the odds ratio, which was calculated using the exponential of the slope. Ninety-five per cent confidence intervals were also calculated.

RESULTS

In total, 20 eligible studies were identified that reported SRE data from phase III trials, of which 11 were suitable for the quantitative analysis. Most of the articles included patients with breast cancer and the remaining involved patients with prostate, renal cell, bladder and lung cancer or other solid tumours. Enrolment periods for all included data ranged from 1990 to 2009. Statistically significant overall downward trends in pathological fractures and the need for surgery were seen over time. Also significant differences between intervention and placebo were seen with all SREs.

CONCLUSION

The decrease in SREs over time may not only be a result of the development of new generation bone-targeted agents, but also due to better systemic management and awareness of events associated with bone metastases.