152 research outputs found

    Expression of nicotinic acetylcholine receptor subunits from parasitic nematodes in Caenorhabditis elegans

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    The levamisole-sensitive nicotinic acetylcholine receptor present at nematode neuromuscular junctions is composed of multiple different subunits, with the exact composition varying between species. We tested the ability of two well-conserved nicotinic receptor subunits, UNC-38 and UNC-29, from Haemonchus contortus and Ascaris suum to rescue the levamisole-resistance and locomotion defects of Caenorhabditis elegans strains with null deletion mutations in the unc-38 and unc-29 genes. The parasite cDNAs were cloned downstream of the relevant C. elegans promoters and introduced into the mutant strains via biolistic transformation. The UNC-38 subunit of H. contortus was able to completely rescue both the locomotion defects and levamisole resistance of the null deletion mutant VC2937 (ok2896), but no C. elegans expressing the A. suum UNC-38 could be detected. The H. contortus UNC-29.1 subunit partially rescued the levamisole resistance of a C. elegans null mutation in unc-29 VC1944 (ok2450), but did cause increased motility in a thrashing assay. In contrast, only a single line of worms containing the A. suum UNC-29 subunit showed a partial rescue of levamisole resistance, with no effect on thrashing

    Explaining Myanmar's Regime Transition: The Periphery is Central

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    In 2010, Myanmar (Burma) held its first elections after 22 years of direct military rule. Few compelling explanations for this regime transition have emerged. This article critiques popular accounts and potential explanations generated by theories of authoritarian ‘regime breakdown’ and ‘regime maintenance’. It returns instead to the classical literature on military intervention and withdrawal. Military regimes, when not terminated by internal factionalism or external unrest, typically liberalise once they feel they have sufficiently addressed the crises that prompted their seizure of power. This was the case in Myanmar. The military intervened for fear that political unrest and ethnic-minority separatist insurgencies would destroy Myanmar’s always-fragile territorial integrity and sovereignty. Far from suddenly liberalising in 2010, the regime sought to create a ‘disciplined democracy’ to safeguard its preferred social and political order twice before, but was thwarted by societal opposition. Its success in 2010 stemmed from a strategy of coercive state-building and economic incorporation via ‘ceasefire capitalism’, which weakened and co-opted much of the opposition. Having altered the balance of forces in its favour, the regime felt sufficiently confident to impose its preferred settlement. However, the transition neither reflected total ‘victory’ for the military nor secured a genuine or lasting peace

    LC-MS/MS quantification of salvinorin A from biological fluids

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    A facile method for quantifying the concentration of the powerful and widely available hallucinogen salvinorin A (a selective kappa opioid agonist) from non-human primate cerebrospinal fluid (CSF) and human plasma has been developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in positive electrospray ionization (ESI) mode. With CSF solid phase extraction can be avoided completely by simply diluting each sample to 10 % (v/v) acetonitrile, 1 % (v/v) formic acid and injecting under high aqueous conditions for analyte focusing. Extensive plasma sample preparation was investigated including protein precipitation, SPE column selection, and plasma particulate removal. Human plasma samples were centrifuged at 21,000 × gravity for 4 minutes to obtain clear particulate-free plasma, from which 300 μl was spiked with internal standard and loaded onto a C18 SPE column with a 100 mg mL−1 loading capacity. Guard columns (C18, hand packed 1 mm × 20 mm) were exchanged after backpressure increased above 4600psi, about 250 injections. A shallow acetonitrile/water gradient was used, 29 to 33% CH3CN over 8 minutes to elute salvinorin A. Reduction of chemical noise was achieved using tandem mass spectrometry with multiple reaction monitoring while sensitivity increases were observed using a 50 μL injection volume onto a small bore analytical column (C18, 1 mm ID × 50 mm) thus increasing peak concentration. Limits of quantification were found to be 0.0125 ng mL−1 (CSF) and 0.05 ng mL−1 (plasma) with interday precision and accuracy below 1.7 % and 9.42 % (CSF) and 3.47 % and 12.37 % (plasma) respectively. This method was used to determine the concentration of salvinorin A from an in vivo Rhesus monkey study and a trial of healthy human research participants, using behaviorally active doses

    Evolutionary change in continuous reaction norms

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    Abstract Understanding the evolution of reaction norms remains a major challenge in ecology and evolution. Investigating evolutionary divergence in reaction norm shapes between populations and closely related species is one approach to providing insights. Here we use a meta-analytic approach to compare divergence in reaction norms of closely related species or populations of animals and plants across types of traits and environments. We quantified mean-standardized differences in overall trait means (Offset) and reaction norm shape (including both Slope and Curvature). These analyses revealed that differences in shape (Slope and Curvature together) were generally greater than differences in Offset. Additionally, differences in Curvature were generally greater than differences in Slope. The type of taxon contrast (species vs. population), trait, organism, and the type and novelty of environments all contributed to the best-fitting models, especially for Offset, Curvature, and the total differences (Total) between reaction norms. Congeneric species had greater differences in reaction norms than populations, and novel environmental conditions increased the differences in reaction norms between populations or species. These results show that evolutionary divergence of curvature is common and should be considered an important aspect of plasticity, together with slope. Biological details about traits and environments, including cryptic variation expressed in novel environmental conditions, may be critical to understanding how reaction norms evolve in novel and rapidly changing environments

    Double Blind Study Investigating the Effect of Different Voice Prostheses on Ease of Swallowing and Residue Post Laryngectomy.

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    Voice prostheses have been examined for their effect on voice production but there is little datum on their effect on swallow function. This study investigated the difference between six commonly available voice prostheses in terms of swallowing. Laryngectomy patients had up to six voice prostheses placed in a random order over two visits. Swallowing was evaluated for each prosthesis using FEES (Fibreoptic Endoscopic Evaluation of Swallowing). After each prosthesis trial, patients self-evaluated their experience of swallowing. Three independent experts indicated which prosthesis they considered best for swallowing for each patient and judged residue on the voice prosthesis and in the upper esophagus. Raters were blinded to participant details, voice prosthesis type and scores of other raters. On patient self-evaluation, scores were equally distributed across all prostheses for swallowing. Experts most frequently chose the Blom Singer Low pressure and Blom Singer Classic Indwelling voice prostheses as best for swallowing but consensus was poor for most patients. Experts found that the Blom Singer Classic Indwelling and the Provox Vega had least residue on the voice prosthesis on thin liquid (p ≤ 0.001) and soft (p = 0.001), respectively. Experts also found that the Blom Singer Low Pressure had least residue in the upper esophagus on soft consistency (p ≤ 0.001). While self-evaluation by patients did not identify a consistently preferred prosthesis for swallow, many patients expressed personal preferences, suggesting benefits to involving patients in the choice of prosthesis. Some voice prostheses may be associated with lower levels of residue on the prosthesis and upper esophagus with certain consistencies

    Clustered Coding Variants in the Glutamate Receptor Complexes of Individuals with Schizophrenia and Bipolar Disorder

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    Current models of schizophrenia and bipolar disorder implicate multiple genes, however their biological relationships remain elusive. To test the genetic role of glutamate receptors and their interacting scaffold proteins, the exons of ten glutamatergic ‘hub’ genes in 1304 individuals were re-sequenced in case and control samples. No significant difference in the overall number of non-synonymous single nucleotide polymorphisms (nsSNPs) was observed between cases and controls. However, cluster analysis of nsSNPs identified two exons encoding the cysteine-rich domain and first transmembrane helix of GRM1 as a risk locus with five mutations highly enriched within these domains. A new splice variant lacking the transmembrane GPCR domain of GRM1 was discovered in the human brain and the GRM1 mutation cluster could perturb the regulation of this variant. The predicted effect on individuals harbouring multiple mutations distributed in their ten hub genes was also examined. Diseased individuals possessed an increased load of deleteriousness from multiple concurrent rare and common coding variants. Together, these data suggest a disease model in which the interplay of compound genetic coding variants, distributed among glutamate receptors and their interacting proteins, contribute to the pathogenesis of schizophrenia and bipolar disorders

    Centerscope

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    Centerscope, formerly Scope, was published by the Boston University Medical Center "to communicate the concern of the Medical Center for the development and maintenance of improved health care in contemporary society.
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