Trimethylsilanol Cleaves Stable Azaylides As Revealed by Unfolding of Robust "Staudinger" Single-Chain Nanoparticles.

Herein, we disclose a unique and selective reagent for the cleavage of stable azaylides prepared by the nonhydrolysis Staudinger reaction, enabling the on-demand unfolding of robust single-chain nanoparticles (SCNPs). SCNPs with promising use in catalysis, nanomedicine, and sensing are obtained through intrachain folding of discrete synthetic polymer chains. The unfolding of SCNPs involving reversible interactions triggered by a variety of external stimuli (e.g., pH, temperature, light, and redox potential) or substances (e.g., competitive reagents, solvents, and anions) is well known. Conversely, methods for the unfolding (i.e., intrachain disassembly) of SCNPs with stronger covalent interactions are scarce. We show that trimethylsilanol (Me3SiOH) triggers the efficient unfolding of robust "Staudinger" SCNPs with stable azaylide (-N=P-) moieties as intrachain cross-linking units showing exceptional stability toward water, air, and CS2, a standard reagent for azaylides. As a consequence, Me3SiOH arises as a rare, exceptional, and valuable reagent for the cleavage of stable azaylides prepared by the nonhydrolysis Staudinger reaction.

Neurological Disorders in Takotsubo Syndrome: Clinical Phenotypes and Outcomes.

BACKGROUND: Neurological disorders as a risk factor for Takotsubo syndrome (TTS) are not well characterized. The aim of the study was to evaluate TTS-associated neurological phenotypes and outcome. METHODS AND RESULTS: Patients with TTS enrolled in the international multicenter GEIST (German Italian Spanish Takotsubo) registry were analyzed. Prevalence, clinical characteristics, and short- and long-term outcomes of patients with TTS were recorded. A subgroup analysis of the 5 most represented neurological disorders was performed. In total, 400 (17%) of 2301 patients had neurological disorders. The most represented neurological conditions were previous cerebrovascular events (39%), followed by neurodegenerative disorders (30.7%), migraine (10%), epilepsy (9.5%), and brain tumors (5%). During hospitalization, patients with neurological disorders had longer in-hospital stay (8 [interquartile range, 5-12] versus 6 [interquartile range, 5-9] days; P<0.01) and more often experienced in-hospital complications (27% versus 16%; P=0.01) mainly driven by cardiogenic shock and in-hospital death (12% versus 7.6% and 6.5% versus 2.8%, respectively; both P<0.01). Survival analysis showed a higher mortality rate in neurological patients both at 60 days and long-term (8.8% versus 3.4% and 23.5% versus 10.1%, respectively; both P<0.01). Neurological disorder was an independent predictor of both the 60-day and long-term mortality rate (odds ratio, 1.78 [95% CI, 1.07-2.97]; P=0.02; hazard ratio, 1.72 [95% CI, 1.33-2.22]; both P<0.001). Patients with neurodegenerative disorders had the worst prognosis among the neurological disease subgroups, whereas patients with TTS with migraine had a favorable prognosis (long-term mortality rates, 29.2% and 9.7%, respectively). CONCLUSIONS: Neurological disorders identify a high-risk TTS subgroup for enhanced short- and long-term mortality rate. Careful recognition of neurological disorders and phenotype is therefore needed.

Metamorphosis of a Commodity Plastic like PVC to Efficient Catalytic Single-Chain Nanoparticles.

We perform the conversion of a commodity plastic of common use in pipes, window frames, medical devices, flexible hoses, etc. like polyvinyl chloride (PVC) to single-chain nanoparticles (SCNPs). SCNPs are versatile, protein-mimetic soft nano-objects of growing interest for catalysis, sensing, and nanomedicine, among other uses. We demonstrate that the metamorphosis process -as induced through metal-free click chemistry- leads to well-defined, uniform SCNPs that are stable during storage in the solid state for months. All the conversion process (from PVC isolation to PVC-SCNPs synthesis) can be run in a green, dipolar aprotic solvent and involving, when required, a simple mixture of ethanol and water (1/1 vol.) as non-solvent. The resulting PVC-SCNPs are investigated as recyclable, metalloenzyme-mimetic catalysts for several representative Cu(II)-catalyzed organic reactions. The method could be valid for the metamorphosis and valorization of other commodity plastics in which it is feasible to install azide functional groups in their linear polymer chains.

Toward Long-Term-Dispersible, Metal-Free Single-Chain Nanoparticles.

We report herein on a new platform for synthesizing stable, inert, and dispersible metal-free single-chain nanoparticles (SCNPs) via intramolecular metal-traceless azide-alkyne click chemistry. It is well known that SCNPs synthesized via Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) often experience metal-induced aggregation issues during storage. Moreover, the presence of metal traces limits its use in a number of potential applications. To address these problems, we selected a bifunctional cross-linker molecule, sym-dibenzo-1,5-cyclooctadiene-3,7-diyne (DIBOD). DIBOD has two highly strained alkyne bonds that allow for the synthesis of metal-free SCNPs. We demonstrate the utility of this new approach by synthesizing metal-free polystyrene (PS)-SCNPs without significant aggregation issues during storage, as demonstrated by small-angle X-ray scattering (SAXS) experiments. Notably, this method paves the way for the synthesis of long-term-dispersible, metal-free SCNPs from potentially any polymer precursor decorated with azide functional groups.

Effects of Acute Vitamin C plus Vitamin E Supplementation on Exercise-Induced Muscle Damage in Runners: A Double-Blind Randomized Controlled Trial.

Considering the existing controversy over the possible role of acute antioxidant vitamins in reducing exercise-induced muscle damage (EIMD), this doubled-blind, randomized and controlled trial aimed to determine whether supplementation with vitamins C and E could mitigate the EIMD in endurance-trained runners (n = 18). The exercise protocol involved a warm-up followed by 6 to 8 bouts of 1 km running at 75% maximum heart rate (HRmax). Two hours before the exercise protocol, participants took the supplementation with vitamins or placebo, and immediately afterwards, blood lactate, rate of perceived exertion and performance were assessed. At 24 h post-exercise, CK, delayed onset muscle soreness and performance were determined (countermovement jump, squat jump and stiffness test). The elastic index and vertical stiffness were calculated using a stiffness test. Immediately after the exercise protocol, all participants showed improved maximum countermovement jump, which only persisted after 24 h in the vitamin group (p < 0.05). In both groups, squat jump height was significantly greater (p < 0.05) immediately after exercise and returned to baseline values after 24 h. The elastic index increased in the vitamin group (p < 0.05), but not in the placebo group. In both groups, lactate levels increased from pre- to immediately post-exercise (p < 0.05), and CK increased from pre- to 24 h post-exercise (p < 0.05). No significant differences between groups were observed in any of the variables (p > 0.05). Vitamin C and E supplementation does not seem to help with EIMD in endurance-trained individuals.

Antiplatelet therapy at discharge and long-term prognosis in Takotsubo syndrome: Insights from the Spanish National Registry (RETAKO).

INTRODUCTION: Endothelial dysfunction and platelet activation have been highlighted as possible mediators in Takotsubo syndrome (TTS). Nevertheless, to date, evidence on the usefulness of antiplatelet therapy in TTS remains controversial. The aim of our study is to evaluate long-term prognosis in TTS patients treated with antiplatelet therapy (APT) at hospitalization discharge. MATERIAL AND METHODS: An ambispective cohort study from the Spanish National Takotsubo Registry database was performed (June 2002 to March 2017). Patients were divided into two groups: those who received APT at hospital discharge (APT cohort) and those who did not (non-APT cohort). Primary endpoint was all-cause death. Secondary endpoints included the composite of recurrence or readmission and a composite of death, recurrence or readmission. RESULTS: From a total of 741 patients, 728 patients were alive at discharge. Follow-up was performed in 544 patients, who were included in the final analysis: 321 patients (59.0%) in the APT cohort and 223 patients (41.0%) in the non-APT cohort. The APT cohort had a better clinical presentation and received more heart failure and acute coronary syndrome-like therapies (angiotensin converting enzyme inhibitors/angiotensin receptor blockers: 75.1% vs. 51.1%; p<0.001, betablockers: 71.3% vs. 50.7%; p<0.001, statins: 67.9% vs. 33.2%; p<0.001). After adjusting for confounder factors, APT at discharge was a protective factor for all-cause death (adjusted hazard ratio (HR) 0.315, 95% confidence interval (CI): 0.106-0.943; p=0.039) and the composite endpoint of all-cause death, recurrence or readmission (adjusted HR 0.318, 95% CI: 0.164-0.619; p=0.001) at month 25 of follow-up. CONCLUSION: Patients with TTS receiving APT at discharge presented better prognosis up to two-years of follow-up compared with their counterparts not receiving APT.

Advances in the Multi-Orthogonal Folding of Single Polymer Chains into Single-Chain Nanoparticles.

The folding of certain proteins (e.g., enzymes) into perfectly defined 3D conformations via multi-orthogonal interactions is critical to their function. Concerning synthetic polymers chains, the "folding" of individual polymer chains at high dilution via intra-chain interactions leads to so-called single-chain nanoparticles (SCNPs). This review article describes the advances carried out in recent years in the folding of single polymer chains into discrete SCNPs via multi-orthogonal interactions using different reactive chemical species where intra-chain bonding only occurs between groups of the same species. First, we summarize results from computer simulations of multi-orthogonally folded SCNPs. Next, we comprehensively review multi-orthogonally folded SCNPs synthesized via either non-covalent bonds or covalent interactions. Finally, we conclude by summarizing recent research about multi-orthogonally folded SCNPs prepared through both reversible (dynamic) and permanent bonds.

Advances in the Phototriggered Synthesis of Single-Chain Polymer Nanoparticles.

Clean use of photons from light to activate chemical reactions offers many possibilities in different fields, from chemistry and biology to materials science and medicine. This review article describes the advances carried out in last decades toward the phototriggered synthesis of single-chain polymer nanoparticles (SCNPs) as soft nanomaterials with promising applications in enzyme-mimicking catalysis and nanomedicine, among other different uses. First, we summarize some different strategies developed to synthesize SCNPs based on photoactivated intrachain homocoupling, phototriggered intrachain heterocoupling and photogenerated collapse induced by an external cross-linker. Next, we comprehensively review the emergent topic of photoactivated multifolding applied to SCNP construction. Finally, we conclude by summarizing recent strategies towards phototriggered disassembly of SCNPs.

Impact of Intravenous Lysine Acetylsalicylate Versus Oral Aspirin on Prasugrel-Inhibited Platelets: Results of a Prospective, Randomized, Crossover Study (the ECCLIPSE Trial).

BACKGROUND: Prasugrel and ticagrelor, new P2Y12-adenosine diphosphate receptor antagonists, are associated with greater pharmacodynamic inhibition and reduction of cardiovascular events compared with clopidogrel in patients with an acute coronary syndrome. However, evidence is lacking about the effects of achieving faster and stronger cyclooxygenase inhibition with intravenous lysine acetylsalicylate (LA) compared with oral aspirin on prasugrel-inhibited platelets. METHODS AND RESULTS: This was a prospective, randomized, single-center, open, 2-period crossover platelet function study conducted in 30 healthy volunteers. Subjects were randomly assigned to receive a loading dose of intravenous LA 450 mg plus oral prasugrel 60 mg or loading dose of aspirin 300 mg plus prasugrel 60 mg orally in a crossover fashion after a 2-week washout period between treatments. Platelet function was evaluated at baseline, 30 minutes, 1 h, 4 h, and 24 h using light transmission aggregometry and vasodilator-stimulated phosphoprotein phosphorylation. The primary end point of the study, inhibition of platelet aggregation after arachidonic acid 1.5 mmol/L at 30 minutes, was significantly higher in subjects treated with LA compared with aspirin: 85.3% versus 44.3%, respectively, P=0.003. This differential effect was observed at 1 hour (P=0.002) and 4 hours (P=0.048), but not at 24 hours. Subjects treated with LA presented less variability and faster and greater inhibition of platelet aggregation with arachidonic acid compared with aspirin. CONCLUSIONS: The administration of intravenous LA resulted in a significant reduction of platelet reactivity compared with oral aspirin on prasugrel-inhibited platelets. Loading dose of LA achieves an earlier platelet inhibition and with less variability than aspirin. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02243137.

Conformations of D-xylose: the pivotal role of the intramolecular hydrogen-bonding.

Crystalline samples of D-xylose have been vaporized by laser ablation and probed in the gas phase using Fourier transform microwave spectroscopy. The rotational spectrum revealed the existence of two α-D-xylopyranose conformers stabilized by the anomeric effect and cooperative hydrogen bond networks. The experiment spectroscopically tracked fine structural changes upon clockwise and counterclockwise arrangements of the OH groups in the observed conformers. The five monosubstituted (13)C species of the most abundant conformer cc-α-(4)C1 have also been observed in their natural abundance, and its structure has been derived. This work demonstrates the pivotal role that the intramolecular hydrogen-bonding network plays in the conformational behavior of free monosaccharides.