Alpha-2-Macroglobulin Is Acutely Sensitive to Freezing and Lyophilization: Implications for Structural and Functional Studies.

Alpha-2-macroglobulin is an abundant secreted protein that is of particular interest because of its diverse ligand binding profile and multifunctional nature, which includes roles as a protease inhibitor and as a molecular chaperone. The activities of alpha-2-macroglobulin are typically dependent on whether its conformation is native or transformed (i.e. adopts a more compact conformation after interactions with proteases or small nucleophiles), and are also influenced by dissociation of the native alpha-2-macroglobulin tetramer into stable dimers. Alpha-2-macroglobulin is predominately present as the native tetramer in vivo; once purified from human blood plasma, however, alpha-2-macroglobulin can undergo a number of conformational changes during storage, including transformation, aggregation or dissociation. We demonstrate that, particularly in the presence of sodium chloride or amine containing compounds, freezing and/or lyophilization of alpha-2-macroglobulin induces conformational changes with functional consequences. These conformational changes in alpha-2-macroglobulin are not always detected by standard native polyacrylamide gel electrophoresis, but can be measured using bisANS fluorescence assays. Increased surface hydrophobicity of alpha-2-macroglobulin, as assessed by bisANS fluorescence measurements, is accompanied by (i) reduced trypsin binding activity, (ii) increased chaperone activity, and (iii) increased binding to the surfaces of SH-SY5Y neurons, in part, via lipoprotein receptors. We show that sucrose (but not glycine) effectively protects native alpha-2-macroglobulin from denaturation during freezing and/or lyophilization, thereby providing a reproducible method for the handling and long-term storage of this protein.Early Career Fellowship from the National Health and Medical Research Council GNT1012521(A.R.W.); Wellcome Trust Programme Grant (J.R.K., C.M.D.) 094425/Z/10/Z; Samsung GRO Grant (M.R.W.)This is the final version of the article. It first appeared from PLoS via http://dx.doi.org/10.1371/journal.pone.013003

Portfolio Vol. II N 4

Browne, Phil. Alumni . Picture. 2. Martindale, Virginia. A Statue By Jude . Prose. 3. Maxwell, Robert. Reflections . Poem. 6. Lewis, Lucy. Quiet Zone . Prose. 7. Varney, Chester. Tinder Box . Prose. 9. Beckham, Adela. Spring Harvest . Poem. 10. Beckham, Adela. Morning . Poem. 10. Black, James. The Drama at Denison . Prose. 11. Mackie, Reino. Landscape . Picture. 6. Flory, Doris. April Showers . Poem. 14. Flory, Doris. Aspiration . Poem. 14. Wager, Dick. Solitude . Poem. 14. Wager, Dick. Regret . Poem. 14. Bastida, Sorella y. Children on the Beach . Picture. 14. Saunders, Paul. Review of New Books . Prose. 15. Smith, Bob. Review of New Recordings . Prose. 15. Mitchell, Dave. A Farmyard . Picture. 16. Bonnet, Elsie. Hidden Village . Picture. 16. Taylor, Dave. Concerning Art . Prose. 17. Browne, Phil. Master Craftsman . Picture. 18. Deeds, Ed. Brothers, Sing On . Prose. 19. Boyd, Kate Olive. Spring at Denison . Poem. 20. Barss, William. Landscape . Picture. 20. Deane, Dorothy. The Taming of the Shrew . Prose. 21

Protecting Vulnerable Research Subjects in Critical Care Trials: Enhancing the Informed Consent Process and Recommendations for Safeguards

Although critically ill patients represent a vulnerable group of individuals, guidelines in research ethics assert that ethically acceptable research may proceed with such vulnerable subjects if additional safeguards are in place to minimize the risk of harm and exploitation. Such safeguards include the proper obtainment of informed consent that avoids the presence of the therapeutic misconception and the assessment of decisional capacity in critically ill patients recruited for research. Also discussed in this review are additional safeguards for such vulnerable subjects, as well as the issues involved with proxy consent. Heightened awareness to principles of ethics and provision of additional safeguards to enhance protections of vulnerable subjects would help to maintain the public trust in the research endeavor

Polymers and biopolymers at interfaces

This review updates recent progress in the understanding of the behaviour of polymers at surfaces and interfaces, highlighting examples in the areas of wetting, dewetting, crystallization, and 'smart' materials. Recent developments in analysis tools have yielded a large increase in the study of biological systems, and some of these will also be discussed, focussing on areas where surfaces are important. These areas include molecular binding events and protein adsorption as well as the mapping of the surfaces of cells. Important techniques commonly used for the analysis of surfaces and interfaces are discussed separately to aid the understanding of their application

The role of impulsivity in the aetiology of drug dependence: reward sensitivity versus automaticity

Journal ArticleResearch Support, Non-U.S. Gov'tCopyright © The Author(s) 2011.RATIONALE: Impulsivity has long been known as a risk factor for drug dependence, but the mechanisms underpinning this association are unclear. Impulsivity may confer hypersensitivity to drug reinforcement which establishes higher rates of instrumental drug-seeking and drug-taking behaviour, or may confer a propensity for automatic (non-intentional) control over drug-seeking/taking and thus intransigence to clinical intervention. METHOD: The current study sought to distinguish these two accounts by measuring Barratt Impulsivity and craving to smoke in 100 smokers prior to their completion of an instrumental concurrent choice task for tobacco (to measure the rate of drug-seeking) and an ad libitum smoking test (to measure the rate of drug-taking-number of puffs consumed). RESULTS: The results showed that impulsivity was not associated with higher rates of drug-seeking/taking, but individual differences in smoking uptake and craving were. Rather, nonplanning impulsivity moderated (decreased) the relationship between craving and drug-taking, but not drug-seeking. CONCLUSIONS: These data suggest that whereas the uptake of drug use is mediated by hypervaluation of the drug as an instrumental goal, the orthogonal trait nonplanning impulsivity confers a propensity for automatic control over well-practiced drug-taking behaviour.MR

An updated systematic review with meta-analysis for the clinical evidence of silymarin

BACKGROUND: The potential benefit of silymarin (special extract from the fruits of Silybum marianum) in the treatment of liver diseases remains a controversial issue. METHODS: For this systematic review electronic databases identified 65 papers for the search terms silymarin, silibinin, silicristin or milk thistle and clinical trial. Only 19 complied with the criteria'double-' or 'single-blind'. These publications were analysed from a clinical point of view and meta-analytic calculations were performed. RESULTS: The clinical evidence ofa therapeutic effect of silymarin in toxic liver diseases is scarce. There is no evidence of a favourable influence on the evolution of viral hepatitis, particularly hepatitis C. In alcoholic liver disease, comparing with placebo, aspartate aminotransferase was reduced in the silymarin-treated groups (p = 0.01) while alkaline phosphatase was not. In liver cirrhosis, mostly alcoholic, total mortality was 16.1% with silymarin vs. 20.5% with placebo (n.s.); liver-related mortality was 10.0% with silymarin vs. 17.3% with placebo(p = 0.01). CONCLUSIONS: Based on the available clinical evidence it can be concluded - concerning possible risks /probable benefits - that it is reasonable to employ silymarin as a supportive element in the therapy of Amanita phalloides poisoning but also (alcoholic and grade Child 'A') liver cirrhosis. A consistent research programme, consolidating existing evidence and exploring new potential uses,would be very welcome