bluuebunny/crossref_metadata_2025_split huggingface dataset:
Systematic review of total pancreatectomy and islet autotransplantation for chronic pancreatitis
Authors: Bramis K , Gordon-Weeks A N , Friend P J , Bastin E , Burls A , Silva M A , Dennison A R 
Published: March 2012

AbstractBackgroundTotal pancreatectomy and islet autotransplantation (TP/IAT) is a treatment option in a subset of patients with chronic pancreatitis. A systematic review of the literature was performed to evaluate the outcome of this procedure, with an attempt to ascertain when it is indicated.MethodsMEDLINE (1950 to present), Embase (1980 to present) and the Cochrane Library were searched to identify studies of outcomes in patients undergoing TP/IAT. Cohort studies that reported the outcomes following the procedure were included. The MOOSE guidelines were used as a basis for this review.ResultsFive studies met the inclusion criteria. The techniques reported for pancreatectomy and islet cell isolation varied between studies. TP/IAT was successful in reducing pain in patients with chronic pancreatitis. Comparing morphine requirements before and after the procedure, two studies recorded significant reductions. Concurrent IAT reduced the insulin requirement after TP; the rate of insulin independence ranged from 46 per cent of patients at 5 years' mean follow-up to 10 per cent at 8 years. The impact on quality of life was poorly reported. The studies reviewed did not provide evidence for optimal timing of TP/IAT in relation to the evolution of chronic pancreatitis.ConclusionThis systematic review showed that TP/IAT had favourable outcomes with regard to pain reduction. Concurrent IAT enabled a significant proportion of patients to remain independent of insulin supplementation.
Nanostructured Manganese Oxide Supported on Carbon Nanotubes for Electrocatalytic Water Splitting
Authors: Mette Katharina , Bergmann Arno , Tessonnier Jean‐Philippe , Hävecker Michael , Yao Lide , Ressler Thorsten , Schlögl Robert , Strasser Peter , Behrens Malte 
Published: March 2012

AbstractIncipient wetness impregnation and a novel deposition symproportionation precipitation were used for the preparation of MnOx/CNT electrocatalysts for efficient water splitting. Nanostructured manganese oxides have been dispersed on commercial carbon nanotubes as a result of both preparation methods. A strong influence of the preparation history on the electrocatalytic performance was observed. The as‐prepared state of a 6.5 wt. % MnOx/CNT sample could be comprehensively characterized by comparison to an unsupported MnOx reference sample. Various characterization techniques revealed distinct differences in the oxidation state of the Mn centers in the as‐prepared samples as a result of the two different preparation methods. As expected, the oxidation state is higher and near +4 for the symproportionated MnOx compared to the impregnated sample, where +2 was found. In both cases an easy adjustability of the oxidation state of Mn by post‐treatment of the catalysts was observed as a function of oxygen partial pressure and temperature. Similar adjustments of the oxidation state are also expected to happen under water splitting conditions. In particular, the 5 wt. % MnO/CNT sample obtained by conventional impregnation was identified as a promising catalytic anode material for water electrolysis at neutral pH showing high activity and stability. Importantly, this catalytic material is comparable to state‐of‐art MnOx catalyst operating in strongly alkaline solutions and, therefore, offers advantages for hydrogen production from waste and sea water under neutral, hence, environmentally benign conditions.
Double Stereodifferentiation in the Catalytic Asymmetric Aziridination of Imines Prepared from α‐Chiral Amines
Authors: Huang Li , Zhang Yu , Staples Richard J. , Huang Rui H. , Wulff William D. 
Published: March 2012

AbstractThe catalytic asymmetric aziridination of imines and diazo compounds (AZ reaction) mediated by boroxinate catalysts derived from the VANOL and VAPOL ligands was investigated with chiral imines derived from five different chiral, disubstituted, methyl amines. The strongest matched and mismatched reactions with the two enantiomers of the catalyst were noted with disubstituted methyl amines that had one aromatic and one aliphatic substituent. The synthetic scope for the AZ reaction was examined in detail for α‐methylbenzyl amine for cis‐aziridines from α‐diazo esters and for trans‐aziridines from α‐diazo acetamides. Optically pure aziridines could be routinely obtained in good yields and with high diastereoselectivity and the minor diastereomer (if any) could be easily separated. The matched case for cis‐aziridines involved the (R)‐amine with the (S)‐ligand, but curiously, for trans‐aziridines the matched case involved the (R)‐amine with the (R)‐ligand for imines derived from benzaldehyde and n‐butanal, and the (R)‐amine with the (S)‐ligand for imines derived from the bulkier aliphatic aldehydes pivaldehyde and cyclohexane carboxaldehyde.
Bistable Cucurbituril Rotaxanes Without Stoppers
Authors: Sinha Mantosh K. , Reany Ofer , Yefet Maayan , Botoshansky Mark , Keinan Ehud 
Published: March 2012

AbstractBistable rotaxanes are important design elements of molecular devices for a broad range of applications, such as controlled drug release, molecular rotary motors, and chemical sensors. The host–guest complexes of cucurbit[6]uril and 1,4‐bis(alkylaminomethyl)benzene were found to exhibit two stable binding modes with an unexpectedly high barrier between them. Their structural and dynamic properties, kinetic and thermodynamic parameters, as well as different chemical reactivity towards the azide–alkyne [3+2] cycloaddition reaction (click chemistry), were discovered by NMR spectroscopy, X‐ray crystallography, and isothermal titration microcalorimetry. The highly stable 2:1 complex, which is formed at room temperature, was found to be a kinetic product, which may be converted to the thermodynamic 1:1 complex upon prolonged heating to 100 °C. The latter is a very stable rotaxane despite the fact that it lacks bulky end groups.
Label‐Free Detection of Nanomolar Unmodified Single‐ and Double‐Stranded DNA by Using Surface‐Enhanced Raman Spectroscopy on Ag and Au Colloids
Authors: Papadopoulou Evanthia , Bell Steven E. J. 
Published: March 2012

AbstractUnlabelled single‐ and double‐stranded DNA (ssDNA and dsDNA, respectively) has been detected at concentrations ≥10−9 M by surface‐enhanced Raman spectroscopy. Under appropriate conditions the sequences spontaneously adsorbed to the surface of both Ag and Au colloids through their nucleobases; this allowed highly reproducible spectra with good signal‐to‐noise ratios to be recorded on completely unmodified samples. This eliminated the need to promote absorption by introducing external linkers, such as thiols. The spectra of model ssDNA sequences contained bands of all the bases present and showed systematic changes when the overall base composition was altered. Initial tests also showed that small but reproducible changes could be detected between oligonucleotides with the same bases arranged in a different order. The spectra of five ssDNA sequences that correspond to different strains of the Escherichia coli bacterium were found to be sufficiently composition‐dependent so that they could be differentiated without the need for any advanced multivariate data analysis techniques.
Relative and Absolute Configuration of Vatiparol (1 mg): A Novel Anti‐inflammatory Polyphenol
Authors: Ge Hui Ming , Sun Han , Jiang Nan , Qin Yan Hua , Dou Huan , Yan Tong , Hou Ya Yi , Griesinger Christian , Tan Ren Xiang 
Published: March 2012

AbstractBioactive natural products offer multiple opportunities for the discovery of novel chemical entities with potential pharmaceutical, nutraceutical and agrochemical applications. Many new organic compounds with novel scaffolds are isolated in small quantities and established methods often fail to determine the structure and bioactivity of such novel natural products. To meet this challenge, we present here a new methodology combining RDC (residual dipolar coupling)‐based NMR spectroscopy in microtubes, with a motif‐inspired biological assessment strategy. Using only one milligram (ca. 1.5 μmol) of sample, the new protocol established the bioactivity as well as the relative and absolute configuration of vatiparol obtained from Vatica parvifolia. Vatiparol is unique in its unprecedented carbon skeleton and selective inhibitory effect on the expression of monocyte chemo‐attractant protein‐1 (MCP‐1, also known as CCL2). The plausible biosynthetic pathway of vatiparol is briefly discussed. The approach introduced here promises to be widely applicable to the determination of the structure and bioactivity of structurally unknown organic samples available in very limited amounts.
Comparison of the Prognostic Value of Peak Creatine Kinase‐MB and Troponin Levels Among Patients With Acute Myocardial Infarction: A Report from the Acute Coronary Treatment and Intervention Outcomes Network Registry–Get With The Guidelines
Authors: Chin Chee Tang , Wang Tracy Y. , Li Shuang , Wiviott Stephen D. , deLemos James A. , Kontos Michael C. , Peterson Eric D. , Roe Matthew T. 
Published: March 2012

AbstractBackground:Although peak creatine kinase‐myocardial band (CK‐MB) and troponin levels have been correlated with mortality among patients with acute myocardial infarction (AMI), the independent prognostic implications of these markers have not been compared.Hypothesis:We hypothesized that in patients with AMI, peak troponin levels (as compared to peak CK‐MB levels) would have greater prognostic value.Methods:We examined AMI patients in the National Cardiovascular Data Registry ACTION Registry–GWTG (Acute Coronary Treatment and Intervention Outcomes Network Registry–Get With The Guidelines) with CK‐MB and troponin I levels recorded, excluding patients who were transferred in or out. Peak marker levels, standardized by the local laboratory upper limit of normal and assay standard deviation, were fitted into the previously validated ACTION Registry–GWTG mortality model to compare prognostic value.Results:Between January 2007 and March 2009, 16 009 ST‐segment elevation myocardial infarction (STEMI) and 26854 non–ST‐segment elevation myocardial infarction (NSTEMI) patients were identified. Peak marker ratios were directly associated with in‐hospital mortality in both STEMI and NSTEMI patients. Peak CK‐MB had slightly greater discrimination compared with peak troponin I in predicting mortality in both STEMI (model C‐statistic 0.881 vs 0.877, P = 0.011) and NSTEMI (C‐statistic 0.831 vs 0.824, P = 0.001) patients.Conclusions:Both peak CK‐MB and peak troponin I levels are independently associated with in‐hospital mortality in this large contemporary database of AMI patients treated in routine practice. Peak marker values slightly improved model performance in prognosticating in‐hospital mortality; the incremental value was higher with CK‐MB than with troponin I. These findings may help to guide future risk stratification algorithms and contribute to more efficient use of serial cardiac marker measurements in clinical practice. Clin. Cardiol. 2011 DOI: 10.1002/clc.21980This project was supported by grant number U18HS016964 from the Agency for Healthcare Research and Quality (AHRQ). The content is solely the responsibility of the authors and does not necessarily represent the official views of the AHRQ. The funding source had no role in the design or implementation of the study, or in the decision to seek publication. The authors have no other funding, financial relationships, or conflicts of interest to disclose.
1H chemical shift magnetic resonance imaging probes with high sensitivity for multiplex imaging
Authors: Yang Yan , Schühle Daniel T. , Dai Guangping , Alford Jamu K. , Caravan Peter 
Published: March 2012

ABSTRACTProton‐based chemical shift imaging probes were encapsulated inside nano‐carriers to increase the sensivitity of the reporters. Co‐encapsulation with a relaxation agent results in improved sensitivity and suppresses background signals. Simultaneous imaging of different chemical shift reporters allows multiplexed detection. Copyright © 2011 John Wiley & Sons, Ltd.
Development of 177Lu‐nanobodies for radioimmunotherapy of HER2‐positive breast cancer: evaluation of different bifunctional chelators
Authors: D'Huyvetter Matthias , Aerts An , Xavier Catarina , Vaneycken Ilse , Devoogdt Nick , Gijs Marlies , Impens Nathalie , Baatout Sarah , Ponsard Bernard , Muyldermans Serge , Caveliers Vicky , Lahoutte Tony 
Published: March 2012

Nanobodies show favourable pharmacokinetic characteristics for tumor targeting, including high tumor‐to‐background‐ratios. Labelled with a therapeutic radionuclide, nanobodies could be used as an adjuvant treatment option for HER2‐overexpressing minimal residual disease. The therapeutic radionuclide Lutetium‐177 is linked to the nanobody using a bifunctional chelator. The choice of the bifunctional chelator could affect the in vivo behaviour of the radiolabeled nanobody. Consequently, we compared four different bifunctional chelators ‐ p‐SCN‐Bn‐DOTA, DOTA‐NHS‐ester, CHX‐A”‐DTPA or 1B4M‐DTPA ‐ in order to select the optimal chemical link between Lutetium‐177 and a HER2 targeting nanobody.MS results revealed different degrees of chelator‐conjugation. High stability in time was observed, together with nanomolar affinities on HER2‐expressing tumor cells. Ex vivo biodistributions as well as SPECT/micro‐CT analyses showed high activities in tumors expressing medium HER2 levels with low background activity except for the kidneys. The 1B4M‐DTPA‐coupled conjugate was further evaluated in a high HER2‐expressing tumor model. Here, tumor uptake values of 5.99 ± 0.63, 5.12 ± 0.17, 2.83 ± 0.36 and 2.47 ± 0.38 %IA/g were obtained at 1, 3, 24 and 48h p.i., which coincided with exceptionally low background values, except for the kidneys, and unprecedented tumor‐to‐background ratios. No specific binding was observed in a HER2‐negative model.In conclusion, the in‐house developed anti‐HER2 nanobody 2Rs15dHIS can be successfully labeled with 177Lu using different bifunctional chelators. Both macrocyclic and acyclic chelators show high stability in time. High specific tumor uptake combined with the lowest background uptake was measured using the 1B4M‐DTPA‐based conjugate. Copyright © 2012 John Wiley & Sons, Ltd.
Prevalence and elimination of sibling neurite convergence in motor units supplying neonatal and adult mouse skeletal muscle
Authors: Teriakidis Adrianna , Willshaw David J. , Ribchester Richard R. 
Published: March 2012

AbstractDuring development, neurons form supernumerary synapses, most of which are selectively pruned leading to stereotyped patterns of innervation. During the development of skeletal muscle innervation, or its regeneration after nerve injury, each muscle fiber is transiently innervated by multiple motor axon branches but eventually by a single branch. The selective elimination of all but one branch is the result of competition between the converging arbors. It is thought that motor neurons initially innervate muscle fibers randomly, but that axon branches from the same neuron (sibling branches) do not converge to innervate the same muscle fiber. However, random innervation would result in many neonatal endplates that are co‐innervated by sibling branches. To investigate whether this occurs we examined neonatal levator auris longus (LAL) and 4th deep lumbrical (4DL) muscles, as well as adult reinnervated deep lumbrical muscles (1–4) in transgenic mice expressing yellow fluorescent protein (YFP) as a reporter. We provide direct evidence of convergence of sibling neurites within single fluorescent motor units, both during development and during regeneration after nerve crush. The incidence of sibling neurite convergence was 40% lower in regeneration and at least 75% lower during development than expected by chance. Therefore, there must be a mechanism that decreases the probability of its occurrence. As sibling neurite convergence is not seen in normal adults, or at later timepoints in regeneration, synapse elimination must also remove convergent synaptic inputs derived from the same motor neuron. Mechanistic theories of synaptic competition should now accommodate this form of isoaxonal plasticity. J. Comp. Neurol., 520:3203–3216, 2012. © 2012 Wiley Periodicals, Inc.
Distinct retinohypothalamic innervation patterns predict the developmental emergence of species‐typical circadian phase preference in nocturnal Norway rats and diurnal nile grass rats
Authors: Todd William D. , Gall Andrew J. , Weiner Joshua A. , Blumberg Mark S. 
Published: March 2012

AbstractHow does the brain develop differently to support nocturnality in some mammals, but diurnality in others? To answer this question, one might look to the suprachiasmatic nucleus (SCN), which is entrained by light via the retinohypothalamic tract (RHT). However, because the SCN is more active during the day in all mammals studied thus far, it alone cannot determine circadian phase preference. In adult Norway rats (Rattus norvegicus), which are nocturnal, the RHT also projects to the ventral subparaventricular zone (vSPVZ), an adjacent region that expresses an in‐phase pattern of SCN‐vSPVZ neuronal activity. In contrast, in adult Nile grass rats (Arvicanthis niloticus), which are diurnal, an anti‐phase pattern of SCN‐vSPVZ neuronal activity is expressed. We hypothesized that these species differences result in part from a weak or absent RHT‐to‐vSPVZ projection in grass rats. Here, using a developmental comparative approach, we assessed species differences in behavior, hypothalamic activity, and RHT anatomy. We report that a robust retina‐to‐vSPVZ projection develops in Norway rats around the end of the second postnatal week when nocturnal wakefulness and the in‐phase pattern of neuronal activity emerge. In grass rats, however, such a projection does not develop and the emergence of the anti‐phase pattern during the second postnatal week is accompanied by increased diurnal wakefulness. When considered within the context of previously published reports on RHT projections in a variety of species, the current findings suggest that how and when the retina connects to the hypothalamus differentially shapes brain and behavior to produce animals that occupy opposing temporal niches. J. Comp. Neurol., 520:3277–3292, 2012. © 2012 Wiley Periodicals, Inc.
Age‐related plasticity in the synaptic ultrastructure of neurons in the mushroom body calyx of the adult honeybee Apis mellifera
Authors: Groh Claudia , Lu Zhiyuan , Meinertzhagen Ian A. , Rössler Wolfgang 
Published: March 2012

AbstractThe mushroom bodies are high‐order sensory integration centers in the insect brain. In the honeybee, their main sensory input regions are large, doubled calyces with modality‐specific, distinct sensory neuropil regions. We investigated adult structural plasticity of input synapses in the microglomeruli of the olfactory lip and visual collar. Synapsin‐immunolabeled whole‐mount brains reveal that during the natural transition from nursing to foraging, a significant volume increase in the calycal subdivisions is accompanied by a decreased packing density of boutons from input projection neurons. To investigate the associated ultrastructural changes at pre‐ and postsynaptic sites of individual microglomeruli, we employed serial‐section electron microscopy. In general, the membrane surface area of olfactory and visual projection neuron boutons increased significantly between 1‐day‐old bees and foragers. Both types of boutons formed ribbon and non‐ribbon synapses. The percentage of ribbon synapses per bouton was significantly increased in the forager. At each presynaptic site the numbers of postsynaptic partners—mostly Kenyon cell dendrites—likewise increased. Ribbon as well as non‐ribbon synapses formed mainly dyads in the 1‐day‐old bee, and triads in the forager. In the visual collar, outgrowing Kenyon cell dendrites form about 140 contacts upon a projection neuron bouton in the forager compared with only about 95 in the 1‐day‐old bee, resulting in an increased divergence ratio between the two stages. This difference suggests that synaptic changes in calycal microcircuits of the mushroom body during periods of altered sensory activity and experience promote behavioral plasticity underlying polyethism and social organization in honeybee colonies. J. Comp. Neurol. 520:3509–3527, 2012. © 2012 Wiley Periodicals, Inc.
Glycine in 1‐Butyl‐3‐Methylimidazolium Acetate and Trifluoroacetate Ionic Liquids: Effect of Fluorination and Hydrogen Bonding
Authors: Podgoršek Ajda , Macchiagodena Marina , Ramondo Fabio , Costa Gomes Margarida F. , Pádua Agílio A. H. 
Published: March 2012

AbstractThe solvation of glycine in two ionic liquids (ILs), namely, 1‐butyl‐3‐methylimidazolium acetate, [C1C4Im][OAc], and 1‐butyl‐3‐methylimidazolium trifluoroacetate, [C1C4Im][TFA], was studied by a combination of experimental and theoretical methods. The solubility of glycine in both ILs was determined at 333.15 K to be (8.1±0.5) and (1.0±0.5) wt % in [C1C4Im][OAc] and [C1C4Im][TFA], respectively. By IR spectroscopy it was found that, when dissolved in the ILs, glycine was mainly present in its zwitterionic form. Structural and energetic aspects of the solvation of glycine in the ILs and in mixtures of ILs and water were investigated by ab initio calculations and molecular dynamic simulations. It was observed that the firstly solvation shell around glycine consisted predominantly of acetate or trifluoroacetate anions, which formed hydrogen bonds either with the carboxylic group of neutral glycine or with the protonated ammonium group of the zwitterionic form. When water is present in the solutions, hydrogen bonds between water and the anion prevail. The overall energy of the system was decomposed into its components between pairs of species. It was established that the dominant contribution to the interaction energy between glycine and the IL was due to hydrogen bonds with the anions and the statistics of hydrogen bonds were analysed.
Chloride Transport
Authors: Edwards John C. 
Published: March 2012

AbstractChloride transport along the nephron is one of the key actions of the kidney that regulates extracellular volume and blood pressure. To maintain steady state, the kidney needs to reabsorb the vast majority of the filtered load of chloride. This is accomplished by the integrated function of sequential chloride transport activities along the nephron. The detailed mechanisms of transport in each segment generate unique patterns of interactions between chloride and numerous other individual components that are transported by the kidney. Consequently, chloride transport is inextricably intertwined with that of sodium, potassium, protons, calcium, and water. These interactions not only allow for exquisitely precise regulation but also determine the particular patterns in which the system can fail in disease states. © 2012 American Physiological Society.Compr Physiol2:1061‐1092, 2012.
Skeletal Muscle Fatigue
Authors: Kent‐Braun Jane A. , Fitts Robert H. , Christie Anita 
Published: March 2012

AbstractSkeletal muscle fatigue is defined as the fall of force or power in response to contractile activity. Both the mechanisms of fatigue and the modes used to elicit it vary tremendously. Conceptual and technological advances allow the examination of fatigue from the level of the single molecule to the intact organism. Evaluation of muscle fatigue in a wide range of disease states builds on our understanding of basic function by revealing the sources of dysfunction in response to disease. © 2012 American Physiological Society.Compr Physiol2:997‐1044, 2012.