NMR spectroscopy combined with paramagnetic relaxation agents was used to study the positioning of the 40-residue Alzheimer Amyloid beta-peptide Abeta(1-40) in SDS micelles. 5-Doxyl stearic acid incorporated into the micelle or Mn(2+) ions in the aqueous solvent were used to determine the position of the peptide relative to the micelle geometry. In SDS solvent, the two alpha-helices induced in Abeta(1-40), comprising residues 15-24, and 29-35, respectively, are surrounded by flexible unstructured regions. NMR signals from these unstructured regions are strongly attenuated in the presence of Mn(2+) showing that these regions are positioned mostly outside the micelle. The central helix (residues 15-24) is significantly affected by 5-doxyl stearic acid however somewhat less for residues 16, 20, 22 and 23. This alpha-helix therefore resides in the SDS headgroup region with the face with residues 16, 20, 22 and 23 directed away from the hydrophobic interior of the micelle. The C-terminal helix is protected both from 5-doxyl stearic acid and Mn(2+), and should be buried in the hydrophobic interior of the micelle. The SDS micelles were characterized by diffusion and (15)N-relaxation measurements. Comparison of experimentally determined translational diffusion coefficients for SDS and Abeta(1-40) show that the size of SDS micelle is not significantly changed by interaction with Abeta(1-40).

Given that oral rehydration is less invasive than IV rehydration with no evidence of important clinical differences, it is the first choice for rehydration in children with AGE and mild-to-moderate dehydration. As the vast majority of children with AGE do not require IV rehydration, oral ondansetron administration to children with significant vomiting should be performed to reduce the use of IV rehydration and the need for hospital admission. In children deemed too unwell to receive oral rehydration therapy, IV ondansetron administration is an option, as its use is associated with lower hospital admission rates. Although probiotics appear to be an effective option for the treatment of AGE amongst hospitalized children, outpatient data is lacking and more studies are urgently needed to determine the optimal organism, dosing and duration of treatment.

The solution structure of Ca 2+ -bound regulatory domain of cardiac troponin C (cNTnC) in complex with the switch region of troponin I (cTnI [147][148][149][150][151][152][153][154][155][156][157][158][159][160][161][162][163] ) and the calmodulin antagonist, N-(6-aminohexyl)-5-chloro-1-naphthalenesulfinamide (W7), has been determined by NMR spectroscopy. The structure reveals that the W7 naphthalene ring interacts with the terminal methyl groups of M47, M60, and M81 as well as aliphatic and aromatic side-chains of several other residues in the hydrophobic pocket of cNTnC. The H3 ring proton of W7 also contacts the methyl groups of I148 and M153 of cTnI [147][148][149][150][151][152][153][154][155][156][157][158][159][160][161][162][163] . The N-(6-aminohexyl) tail interacts primarily with the methyl groups of V64 and M81, which are located on the C-and D-helices of cNTnC. Compared to the structure of the cNTnC•Ca 2+ •W7 complex (Hoffman, R. M. B. and Sykes, B. D. (2009) Biochemistry 48, 5541-5552), the tail of W7 reorients slightly towards the surface of cNTnC while the ring remains in the hydrophobic pocket. The positively charged -NH 3 + group from the tail of W7 repels the positively charged R147 of cTnI [147][148][149][150][151][152][153][154][155][156][157][158][159][160][161][162][163] . As a result, the N-terminus of the peptide moves away from cNTnC and the helical content of cTnI [147][148][149][150][151][152][153][154][155][156][157][158][159][160][161][162][163] is diminished, when compared to the structure of cNTnC•Ca 2+ •cTnI [147][148][149][150][151][152][153][154][155][156][157][158][159][160][161][162][163] (Li, M. X., Spyracopoulos, L., and Sykes B. D. (1999) Biochemistry 38, 8289-8298). Thus the ternary structure cNTnC•Ca 2+ •W7•cTnI [147][148][149][150][151][152][153][154][155][156][157][158][159][160][161][162][163] reported in this study offers an explanation for the ∼13-fold affinity reduction of cTnI [147][148][149][150][151][152][153][154][155][156][157][158][159][160][161][162][163] for cNTnC•Ca 2+ in the presence of W7, and provides a structural basis for the inhibitory effect of W7 in cardiac muscle contraction. This generates molecular insight into structural features that are useful for the design of cTnC-specific Ca 2+ -desensitizing drugs. Keywordstroponin; structure; drugs; mechanism; inhibition A healthy human heart generates ∼3 billion contractile cycles over an average life span. Each contractile cycle involves systolic activation and diastolic relaxation, regulated by Ca 2+ association and dissociation from troponin in the cardiac myofilaments. Troponin is a *To whom correspondence should be addressed. Phone Number: (780) 492-5460, Fax Number: (780) 492-0886, brian.sykes@ualberta.ca. Data Deposition: The atomic coordinates have been deposited in the RCSB Protein Data Bank (PDB accession code: 2KRD) Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early ve...

It is not certain whether the helix propagation parameters s(n)() (i.e., the equilibrium constants between (n - 1)- and n-residue long alpha-helices) determined from numerous studies of rather long model peptides are applicable for description of the initial steps of the helix formation during the protein folding process. From fluorescence, NMR, and calorimetric studies of a series of model peptides, containing the La(3+)-binding sequence nucleating the helix (Siedlecka, M., Goch, G., Ejchart, A., Sticht, H., and Bierzynski, A. (1999) Proc. Natl. Acad. Sci. U.S.A. 96, 903-908), we have determined, at 25 degrees C, the average values of the enthalpy DeltaH(n)() and of the helix growth parameters s(n)() describing the first four steps of helix propagation in polyalanine. The absolute values of the C-cap parameters, describing the contribution of the C-terminal residues to the helix free energy, have also been estimated for alanine (1.2 +/- 0.5) and NH(2) group (1.6 +/- 0.7). The initial four steps of the helix growth in polyalanine can be described by a common propagation parameter s = 1.54 +/- 0.04. The enthalpy DeltaH(n)() is also constant and equals -980 +/- 100 cal mol(-)(1).

Practitioners may prescribe systemic corticosteroids in otherwise healthy children when indicated for the management of acute respiratory conditions (i.e. infections or asthma exacerbations) with minimal concern about short-term adverse effects.

Background Overviews of reviews are an evolving form of evidence synthesis. The Cochrane Child Health Field has been producing overviews since 2006, during which time the methods that have been used have changed, both due to the development of guidance within The Cochrane Collaboration and to the decisions made by individual author teams. This paper studies the first 29 overviews published in EBCH. Objectives To describe some aspects of the approaches taken in EBCH overviews to producing evidence syntheses relevant to the healthcare needs of children; to highlight the contribution that overviews can make to the knowledge base for treatment for a particular population. Methods Data was extracted on: whether the overview included systematic review (SR) data only, or also data from individual trials not present in the included SRs; name(s) of the Cochrane Review Group (CRG) that prepared the included SRs; topics of the overviews as compared to the topics of the included reviews; age‐subgroup analyses presented in the overviews. Results In 23 overviews, all published in 2012, the authors included trial data as well as SR data; two overviews addressed conditions not explicitly addressed by the included reviews; three overviews included pre‐specified age‐subgroup analyses. Discussion The aim of clinical relevance has been achieved by means such as: drawing from reviews produced by multiple CRGs; using SR evidence to explore clinically relevant topics that may not match exactly with the topics covered by the SRs; ensuring that the evidence in overviews is as up to date as possible by redoing searches and including trials not incorporated in the included SRs; and, where permitted by the data, using age‐subgroup analyses to present the data in a way which matches the stages of childhood development. Conclusion Overview authors are dependent on the nature of the data and methods reported in the included SRs. This suggests a need for further study about how SRs could be conducted in order to facilitate the conduct of overviews. Copyright © 2013 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd. The Cochrane Collaboration

Six novel cyclic enkephalin analogues have been synthesized. Cyclization of the linear peptides containing basic amino acid residues in position 2 and 5 was achieved by treatment with bis(4-nitrophenyl)carbonate. It was found that some of the compounds exibit unusually high mu-opioid activity in the guinea pig ileum (GPI) assay. The 18-membered analogue cyclo(N(epsilon),N(beta)-carbonyl-D-Lys2,Dap5)-enkephalinamide turned out to be one of the most potent mu-agonists reported so far. NMR spectra of the peptides were recorded and structural parameters were determined. The conformational space was exhaustively examined for each of them using the electrostatically driven Monte Carlo method. Each peptide was finally described as an ensemble of conformations. A model of the bioactive conformation of this class of opioid peptides was proposed.

Background Two large surveillance studies in adults with asthma have found an increased risk of asthma-related mortality in those who took regular salmeterol as monotherapy in comparison to placebo or regular salbutamol. No similar sized surveillance studies have been carried out in children with asthma, and we remain uncertain about the comparative safety of regular combination therapy with either formoterol or salmeterol in children with asthma. Objectives We have used the paediatric trial results from Cochrane systematic reviews to assess the safety of regular formoterol or salmeterol, either as monotherapy or as combination therapy, in children with asthma. Methods We included Cochrane reviews relating to the safety of regular formoterol and salmeterol from a search of the Cochrane Database of Systematic Reviews conducted in May 2012, and ran updated searches for each of the reviews. These were independently assessed. All the reviews were assessed for quality using the AMSTAR tool. We extracted the data relating to children from each review and from new trials found in the updated searches (including risks of bias, study characteristics, serious adverse event outcomes, and control arm event rates). The safety of regular formoterol and salmeterol were assessed directly from the paediatric trials in the Cochrane reviews of monotherapy and combination therapy with each product. Then monotherapy was indirectly compared to combination therapy by looking at the differences between the pooled trial results for monotherapy and the pooled results for combination therapy. The comparative safety of formoterol and salmeterol was assessed using direct evidence from trials that randomised children to each treatment; this was combined with the result of an indirect comparison of the combination therapy trials, which represents the difference between the pooled results of each product when randomised against inhaled corticosteroids alone. Main results We identified six high quality, up to date Cochrane reviews. Four of these related to the safety of regular formoterol or salmeterol (as monotherapy or combination therapy) and these included 19 studies in children. We added data from two recent studies on salmeterol combination therapy in 689 children which were published after the relevant Cochrane review had been completed, making a total of 21 trials on 7474 children (from four to 17 years of age). The two remaining reviews compared the safety of formoterol with salmeterol from trials randomising participants to one or other treatment, but the reviews only included a single trial in children in which there were 156 participants. Only one child died across all the trials, so impact on mortality could not be assessed. We found a statistically significant increase in the odds of suffering a non-fatal serious adverse event of any cause in children on formoterol monotherapy (Peto odds ratio (OR) 2.48; 95% confidence interval (CI) 1.27 to 4.83, I2 = 0%, 5 trials, N = 1335, high quality) and smaller increases in odds which ...