Molecular-beam epitaxy of p-type m-plane GaN

We report on the plasma-assisted molecular-beam epitaxy of Mg-doped (10 (1) over bar0) GaN on (10 (1) over bar0) 6H-SiC. Secondary ion mass spectroscopy measurements show the incorporation of Mg into the GaN films with an enhanced Mg incorporation under N-rich conditions relative to Ga-rich growth. Transport measurements of Mg-doped layers grown under Ga-rich conditions show hole concentrations in the range of p=1x10(18) to p=7x10(18) cm(-3) and a dependence between hole concentration and Mg beam equivalent pressure. An anisotropy in in-plane hole mobilities was observed, with the hole mobility parallel to [11 (2) over bar0] being higher than that parallel to [0001] for the same hole concentration. Mobilities parallel to [11 (2) over bar0] were as high as similar to 11.5 cm(2)/Vs (at p similar to 1.8 x 10(18) cm(-3)). (c) 2005 American Institute of Physics

Antibodies Targeted to the Brain with Image-Guided Focused Ultrasound Reduces Amyloid-β Plaque Load in the TgCRND8 Mouse Model of Alzheimer's Disease

Immunotherapy for Alzheimer's disease (AD) relies on antibodies directed against toxic amyloid-beta peptide (Aβ), which circulate in the bloodstream and remove Aβ from the brain [1], [2]. In mouse models of AD, the administration of anti-Aβ antibodies directly into the brain, in comparison to the bloodstream, was shown to be more efficient at reducing Aβ plaque pathology [3], [4]. Therefore, delivering anti-Aβ antibodies to the brain of AD patients may also improve treatment efficiency. Transcranial focused ultrasound (FUS) is known to transiently-enhance the permeability of the blood-brain barrier (BBB) [5], allowing intravenously administered therapeutics to enter the brain [6]–[8]. Our goal was to establish that anti-Aβ antibodies delivered to the brain using magnetic resonance imaging-guided FUS (MRIgFUS) [9] can reduce plaque pathology. To test this, TgCRND8 mice [10] received intravenous injections of MRI and FUS contrast agents, as well as anti-Aβ antibody, BAM-10. MRIgFUS was then applied transcranially. Within minutes, the MRI contrast agent entered the brain, and BAM-10 was later found bound to Aβ plaques in targeted cortical areas. Four days post-treatment, Aβ pathology was significantly reduced in TgCRND8 mice. In conclusion, this is the first report to demonstrate that MRIgFUS delivery of anti-Aβ antibodies provides the combined advantages of using a low dose of antibody and rapidly reducing plaque pathology

IFNβ Protects Neurons from Damage in a Murine Model of HIV-1 Associated Brain Injury.

Infection with human immunodeficiency virus-1 (HIV-1) causes brain injury. Type I interferons (IFNα/β) are critical mediators of any anti-viral immune response and IFNβ has been implicated in the temporary control of lentiviral infection in the brain. Here we show that transgenic mice expressing HIV-1 envelope glycoprotein 120 in their central nervous system (HIVgp120tg) mount a transient IFNβ response and provide evidence that IFNβ confers neuronal protection against HIVgp120 toxicity. In cerebrocortical cell cultures, neuroprotection by IFNβ against gp120 toxicity is dependent on IFNα receptor 1 (IFNAR1) and the β-chemokine CCL4, as IFNAR1 deficiency and neutralizing antibodies against CCL4, respectively, abolish the neuroprotective effects. We find in vivo that IFNβ mRNA is significantly increased in HIVgp120tg brains at 1.5, but not 3 or 6 months of age. However, a four-week intranasal IFNβ treatment of HIVgp120tg mice starting at 3.5 months of age increases expression of CCL4 and concomitantly protects neuronal dendrites and pre-synaptic terminals in cortex and hippocampus from gp120-induced damage. Moreover, in vivo and in vitro data suggests astrocytes are a major source of IFNβ-induced CCL4. Altogether, our results suggest exogenous IFNβ as a neuroprotective factor that has potential to ameliorate in vivo HIVgp120-induced brain injury

Sodium/myo-Inositol Transporters: Substrate Transport Requirements and Regional Brain Expression in the TgCRND8 Mouse Model of Amyloid Pathology

Inositol stereoisomers, myo- and scyllo-inositol, are known to enter the brain and are significantly elevated following oral administration. Elevations in brain inositol levels occur across a concentration gradient as a result of active transport from the periphery. There are two sodium/myo-inositol transporters (SMIT1, SMIT2) that may be responsible for regulating brain inositol levels. The goals of this study were to determine the effects of aging and Alzheimer's disease (AD)-like amyloid pathology on transporter expression, to compare regional expression and to analyze substrate requirements of the inositol transporters. QPCR was used to examine expression of the two transporters in the cortex, hippocampus and cerebellum of TgCRND8 mice, a mouse model of amyloid pathology, in comparison to non-transgenic littermates. In addition, we examined the structural features of inositol required for active transport, utilizing a cell-based competitive uptake assay. Disease pathology did not alter transporter expression in the cortex or hippocampus (p>0.005), with only minimal effects of aging observed in the cerebellum (SMIT1: F2,26 = 12.62; p = 0.0002; SMIT2: F2,26 = 8.71; p = 0.0015). Overall, brain SMIT1 levels were higher than SMIT2, however, regional differences were observed. For SMIT1, at 4 and 6 months cerebellar SMIT1 levels were significantly higher than cortical and hippocampal levels (p<0.05). For SMIT2, at all three ages both cortical and cerebellar SMIT2 levels were significantly higher than hippocampal levels (p<0.05) and at 4 and 6 months of age, cerebellar SMIT2 levels were also significantly higher than cortical levels (p<0.05). Inositol transporter levels are stably expressed as a function of age, and expression is unaltered with disease pathology in the TgCRND8 mouse. Given the fact that scyllo-inositol is currently in clinical trials for the treatment of AD, the stable expression of inositol transporters regardless of disease pathology is an important finding

Xanthene Food Dye, as a Modulator of Alzheimer's Disease Amyloid-beta Peptide Aggregation and the Associated Impaired Neuronal Cell Function

Alzheimer's disease (AD) is the most common form of dementia. AD is a degenerative brain disorder that causes problems with memory, thinking and behavior. It has been suggested that aggregation of amyloid-beta peptide (Aβ) is closely linked to the development of AD pathology. In the search for safe, effective modulators, we evaluated the modulating capabilities of erythrosine B (ER), a Food and Drug Administration (FDA)-approved red food dye, on Aβ aggregation and Aβ-associated impaired neuronal cell function.In order to evaluate the modulating ability of ER on Aβ aggregation, we employed transmission electron microscopy (TEM), thioflavin T (ThT) fluorescence assay, and immunoassays using Aβ-specific antibodies. TEM images and ThT fluorescence of Aβ samples indicate that protofibrils are predominantly generated and persist for at least 3 days. The average length of the ER-induced protofibrils is inversely proportional to the concentration of ER above the stoichiometric concentration of Aβ monomers. Immunoassay results using Aβ-specific antibodies suggest that ER binds to the N-terminus of Aβ and inhibits amyloid fibril formation. In order to evaluate Aβ-associated toxicity we determined the reducing activity of SH-SY5Y neuroblastoma cells treated with Aβ aggregates formed in the absence or in the presence of ER. As the concentration of ER increased above the stoichiometric concentration of Aβ, cellular reducing activity increased and Aβ-associated reducing activity loss was negligible at 500 µM ER.Our findings show that ER is a novel modulator of Aβ aggregation and reduces Aβ-associated impaired cell function. Our findings also suggest that xanthene dye can be a new type of small molecule modulator of Aβ aggregation. With demonstrated safety profiles and blood-brain permeability, ER represents a particularly attractive aggregation modulator for amyloidogenic proteins associated with neurodegenerative diseases

Capturing the personal through the lens of the professional: The use of external data sources in autoethnography

This article shows how external data sources can be utilised in autoethnographic research. Beginning with an account of a critical incident that examines the incompatibility of private and professional identities, I show how, through the collection of data sources, I capture the impact of homophobic and heteronormative discursive practices on health, wellbeing and identity. In the critical incident, I explore how I prospered as a teacher at a British village school for almost 10 years by censoring my sexuality and carefully managing the intersection between my private and professional identities. However, when a malicious and homophobic neighbour and parent of children at the school exposed my sexuality to the Headteacher, I learned the extent to which the rural school community privileged and protected the heteronormative discourse. A poststructuralist theoretical framework underpins this article. My experience of being a subject is understood as the outcome of discursive practices. Sexual identity, teacher identity and autoethnographer identity are understood to be fluid, and constantly produced and reproduced in response to social, cultural and political influences. The article describes how email correspondence, medical records and notes from a course of cognitive behaviour therapy were deployed to augment my personal recollection and give a depth and richness to the narrative. As the critical incident became a police matter, examination takes place of how I sought to obtain and utilise data from the police national computer in the research. Attempts to collect data from the police and Crown Prosecution Service were problematic and provided an unexpected development in the research and offered additional insight into the nature of the British rural community and its police force

Safety and efficacy of the supreme biodegradable polymer sirolimus-eluting stent in patients with diabetes mellitus

Patients with diabetes mellitus (DM) have worse outcomes following percutaneous coronary intervention than nondiabetic patients. The novel Supreme DES is a biodegradable polymer sirolimus-eluting stent designed to synchronize early drug delivery, limiting the potential for long-term inflammatory response. The purpose of this study was to evaluate the safety and efficacy of the Supreme DES in patients with DM. Methods This is a prespecified analysis of the diabetic subgroup from the PIONEER III randomized (2:1), controlled trial, comparing the Supreme DES with a durable polymer everolimus-eluting stent (DP-EES). The primary safety and efficacy composite endpoint was target lesion failure at 1 year, a composite of cardiac death, target vessel myocardial infarction, or clinically driven target lesion revascularization. Results The PIONEER III trial randomized 1629 patients, of which 494 (30.3%) had DM with 331 (398 lesions) randomly assigned to Supreme DES and 163 (208 lesions) to DP-EES. Among patients with DM, target lesion failure at 1 year was 6.1% (20/331) with Supreme DES vs 3.7% (6/163) with DP-EES (hazard ratio = 1.65; 95% confidence interval = 0.66-4.10, P = .28). The composite of cardiac death or target vessel myocardial infarction was 3.3% (11/331) with Supreme DES and 3.7% (6/163) with DP-EES (hazard ratio = 0.90; 95% confidence interval = 0.33-2.44, P = .83). There were no significant differences in other secondary endpoints. Conclusions This prespecified substudy of the PIONEER III trial demonstrated the relative safety and efficacy of the novel Supreme DES when compared with commercially available DP-EES in diabetics at 1 year. Longer term follow-up will be required to ensure continued safety and efficacy of the Supreme DES

Weak Glycolipid Binding of a Microdomain-Tracer Peptide Correlates with Aggregation and Slow Diffusion on Cell Membranes

10.1371/journal.pone.0051222PLoS ONE712

Monitoring Alzheimer Amyloid Peptide Aggregation by EPR

Plaques containing the aggregated β-Amyloid (Aβ) peptide in the brain are the main indicators of Alzheimer’s disease. Fibrils, the building blocks of plaques, can also be produced in vitro and consist of a regular arrangement of the peptide. The initial steps of fibril formation are not well understood and could involve smaller aggregates (oligomers) of Aβ. Such oligomers have even been implicated as the toxic agents. Here, a method to study oligomers on the time scale of aggregation is suggested. We have labeled the 40 residue Aβ peptide variant containing an N-terminal cysteine (cys-Aβ) with the MTSL [1-oxyl-2,2,5,5-tetramethyl-Δ-pyrroline-3-methyl] methanethiosulfonate spin label (SL-Aβ). Fibril formation in solutions of pure SL-Aβ and of SL-Aβ mixed with Aβ was shown by Congo-red binding and electron microscopy. Continuous-wave 9 GHz electron paramagnetic resonance reveals three fractions of different spin-label mobility: one attributed to monomeric Aβ, one to a multimer (8–15 monomers), and the last one to larger aggregates or fibrils. The approach, in principle, allows detection of oligomers on the time scale of aggregation

A Randomized Comparison of the Endeavor Zotarolimus-Eluting Stent Versus the TAXUS Paclitaxel-Eluting Stent in De Novo Native Coronary Lesions 12-Month Outcomes From the ENDEAVOR IV Trial

ObjectivesThe ENDEAVOR IV (Randomized Comparison of Zotarolimus-Eluting and Paclitaxel-Eluting Stents in Patients with Coronary Artery Disease) trial evaluated the safety and efficacy of the zotarolimus-eluting stent (ZES) compared with the paclitaxel-eluting stent (PES).BackgroundFirst-generation drug-eluting stents have reduced angiographic and clinical restenosis, but long-term safety remains controversial. A second-generation drug-eluting stent, which delivers zotarolimus, a potent antiproliferative agent, via a biocompatible phosphorylcholine polymer on a cobalt alloy thin-strut stent has shown promising experimental and early clinical results.MethodsThis is a prospective, randomized (1:1), single-blind, controlled trial comparing outcomes of patients with single de novo coronary lesions treated with ZES or PES. The primary end point was noninferiority of 9-month target vessel failure defined as cardiac death, myocardial infarction, or target vessel revascularization.ResultsAmong a total of 1,548 patients assigned to ZES (n = 773) or PES (n = 775), at 9 months, ZES was noninferior to PES with rates of target vessel failure 6.6% versus 7.1%, respectively (pnoninferiority≤ 0.001). There were fewer periprocedural myocardial infarctions with ZES (0.5% vs. 2.2%; p = 0.007), whereas at 12 months, there were no significant differences between groups in rates of cardiac death, myocardial infarction, target vessel revascularization, or stent thrombosis. Although incidence of 8-month binary angiographic in-segment restenosis was higher in patients treated with ZES versus PES (15.3% vs. 10.4%; p = 0.284), rates of 12-month target lesion revascularization were similar (4.5% vs. 3.2%; p = 0.228), especially in patients without planned angiographic follow-up (3.6% vs. 3.2%; p = 0.756).ConclusionsThese findings demonstrate that ZES has similar clinical safety and efficacy compared with PES in simple and medium complexity single de novo coronary lesions. (ENDEAVOR IV Clinical Trial; NCT00217269