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Background Assessing bleeding risk during the decision-making process of starting oral anticoagulation (OAC) therapy in atrial fibrillation (AF) patients is essential. Several bleeding risk scores have been proposed for vitamin K antagonist users but, few studies have focused on validation of these bleeding risk scores in patients taking direct oral anticoagulants (DOACs). The aim was to compare the predictive ability of HAS-BLED and ORBIT bleeding risk scores in AF patients taking rivaroxaban in the EMIR (‘Estudio observacional para la identificación de los factores de riesgo asociados a eventos cardiovasculares mayores en pacientes con fibrilación auricular no valvular tratados con un anticoagulante oral directo [Rivaroxaban]) Study. Methods and results EMIR Study was an observational, multicenter, post-authorization, and prospective study that involved AF patients under OAC with rivaroxaban at least 6 months before enrolment. We analysed baseline clinical characteristics and adverse events after 2.5 years of follow-up and validated the predictive ability of HAS-BLED and ORBIT scores for major bleeding (MB) events. We analysed 1433 patients with mean age of 74.2 ± 9.7 (44.5% female). Mean HAS-BLED score was 1.6 ± 1.0 and ORBIT score was 1.1 ± 1.2. The ORBIT score categorised a higher proportion of patients as ‘low-risk’ (87.1%) compared with 53.5% using the HAS-BLED score. There were 33 MB events (1.04%/year) and 87 patients died (2.73%/year). Both HAS-BLED and ORBIT had a good predictive ability for MB{Area under the curve (AUC) 0.770, [95% confidence interval (CI) 0.693–0.847; P Conclusion In a prospective real-world AF population under rivaroxaban from EMIR registry, the HAS-BLED score had good predictive performance and calibration compared with ORBIT score for MB events. ORBIT score presented worse calibration than HAS-BLED in this DOAC treated population.

Although it is known that the first case of cancer was recorded in ancient Egypt around 1600 BC, it was not until 1917 during the First World War and the development of mustard gas that chemotherapy against cancer became relevant; however, its properties were not recognised until 1946 to later be used in patients. In this sense, the use of metallopharmaceuticals in cancer therapy was extensively explored until the 1960s with the discovery of cisplatin and its anticancer activity. From that date to the present, the search for more effective, more selective metallodrugs with fewer side effects has been an area of continuous exploration. Efforts have led to considering a wide variety of metals from the periodic table, mainly from the d-block, as well as a wide variety of organic ligands, preferably with proven biological activity. In this sense, various research groups have found an ideal binder in Schiff bases, since their raw materials are easily accessible, their synthesis conditions are friendly and their denticity can be manipulated. Therefore, in this review, we have explored the anticancer and antitumor activity reported in the literature for coordination complexes of d-block metals coordinated with tridentate Schiff bases (O N O and O N N) derived from salicylaldehyde. For this work, we have used the main scientific databases CCDC® and SciFinder®.

Cardiomyocytes derived from human pluripotent stem cells (hPSC-CMs) hold a great potential as human in vitro models for studying heart disease and for drug safety screening. Nevertheless, their associated immaturity relative to the adult myocardium limits their utility in cardiac research. In this study, we describe the development of a platform for generating three-dimensional engineered heart tissues (EHTs) from hPSC-CMs for the measurement of force while under mechanical and electrical stimulation. The modular and versatile EHT platform presented here allows for the formation of three tissues per well in a 12-well plate format, resulting in 36 tissues per plate. We compared the functional performance of EHTs and their histology in three different media and demonstrated that tissues cultured and maintained in maturation medium, containing triiodothyronine (T3), dexamethasone, and insulin-like growth factor-1 (TDI), resulted in a higher force of contraction, sarcomeric organization and alignment, and a higher and lower inotropic response to isoproterenol and nifedipine, respectively. Moreover, in this study, we highlight the importance of integrating a serum-free maturation medium in the EHT platform, making it a suitable tool for cardiovascular research, disease modeling, and preclinical drug testing.

The encapsulation of therapeutic agents, like drugs and vaccines, into colloidal particles, offers an attractive strategy to enhance their efficacy. Previously, we reported the development of guanosine-based supramolecular colloidal particles suitable for encapsulating a broad array of guests ranging from small molecule drugs, like doxorubicin, to proteins, like GFP. Many biomedical applications of such particles require a precise determination of the amount of encapsulated therapeutic agents. Despite the many publications describing the development of particle-based delivery systems, a general method for the precise and quick quantification of the encapsulated payload is still lacking. Here we report a method based on flow cytometry (FC) measurements complexes made from guanosine-based particles and a variety of commercially available fluorescent dyes. This method allows us to determine the apparent affinities of such dyes for two variants of these particles, which in turn unveils insightful structure affinity relationships. In contrast to current methods, such as those that rely on fluorescence microscopy based on measurements of absorption/fluorescence of dissolved particles or on the supernatant of the solution, the reported method is suitable for high throughput screening and more reproducible results. The protocol described here should be applicable to a wide variety of colloidal particles being developed around the world. Our group is currently expanding the scope to quantify the encapsulation of other molecules of biomedical interest, such as proteins and nucleic acids.

Guanosine and related derivatives self-assemble in the presence of cations like potassium into supramolecular G-quadruplexes (SGQs), where four guanine moieties form planar tetrads (T) that coaxially stack into columnar aggregates with broad size distributions. However, SGQs made from 8-aryl-2’-deoxyguanosine derivatives (8ArGs), form mostly octamers, or two-tetrad (2T)-SGQs, while some form dodecamers (3T-SGQs), or hexadecamers (4T-SGQs), and none reported to date form higher assemblies. A theoretical model that addresses the configurational space available for the multiple pathways available for 8ArGs to self-assemble into SGQs is used to frame a series of molecular dynamics simulations (MDS) with selected SGQs. Some key insights from this work include: (a) The predicted entropic costs are not significantly higher for SGQs with more subunits due to their hierarchical assembly pathways; (b) The multiple isomeric SGQs vary in the interfacial contacts between consecutive tetrads, due to their two distinct sides (head, h; tail, t), with the MDS supporting the predicted order of stability of hh > ht > tt for octamers. (c) Such order also applies to dodecamers and hexadecamers, but with context-dependent exceptions due to strong allosteric effects. (d) The main factor disfavoring the tt interface is the repulsive dipolar interactions between the O4’ from ribose moieties on adjacent tetrads. (e) SGQs with 5 or more tetrads are disfavored because the attractive interactions are not large or strong enough to overcome the many repulsive forces resulting from the addition of further tetrads. We expect these findings provide some guidelines to enable the further development of SGQs into functional materials.

Cardiovascular disease is often associated with cardiac remodeling, including cardiac fibrosis, which may lead to increased stiffness of the heart wall. This stiffness in turn may cause subsequent failure of cardiac myocytes, however the response of these cells to increased substrate stiffness is largely unknown. To investigate the contractile response of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) to increased substrate stiffness, we generated a stable transgenic human pluripotent stem cell line expressing a fusion protein of alpha-Actinin and fluorescent mRubyII in a previously characterized NKX2.5-GFP reporter line. Cardiomyocytes differentiated from this line were subjected to a substrate with stiffness ranging from 4 kPa to 101 kPa, while contraction of sarcomeres and bead displacement in the substrate were measured for each single cardiomyocyte. We found that sarcomere dynamics in hPSC-CMs on polyacrylamide gels of increasing stiffness are not affected above physiological levels (21 kPa), but that contractile force increases up to a stiffness of 90 kPa, at which cell shortening, deducted from bead displacement, is significantly reduced compared to physiological stiffness. We therefore hypothesize that this discrepancy may be the cause of intracellular stress that leads to hypertrophy and consequent heart failure in vivo.

Objective To identify factors associated with poor anticoagulation control with vitamin K antagonists (VKA) among outpatients with nonvalvular atrial fibrillation (NVAF) attended in Neurology and Internal Medicine in Spain. Methods Cross-sectional and multicenter study, from the ALADIN database, of outpatients with NVAF treated with VKA and attended in Internal Medicine and Neurology in Spain. Rates of anticoagulation control were determined with the direct and Rosendaal methods, considering data from the 6 months before the inclusion. Results Out of 1337 patients included in the ALADIN study, 750 were taking VKA, and complete information about INR values in the last 6 months was available in 383 patients. Mean scores of Charlson Index, CHADS2, CHA2DS2-VASc and HAS-BLED were 1.94 ± 1.54; 3.10 ± 1.26; 4.63 ± 1.54, and 2.20 ± 0.90, respectively. 46.2% and 47.0% of patients had an adequate anticoagulation control according to the direct and Rosendaal methods, respectively. Inadequate anticoagulation control according to the direct method was associated with diabetes (OR: 2.511; 95% CI: 1.144–5.659), prior labile INR (OR: 35.371; 95% CI: 15.058–83.083) and the determination of >6 INR controls in the last 6 months (OR: 4.747; 95% CI: 2.094–10.759), and according to the Rosendaal method, with prior labile INR (p Conclusions Despite the high thromboembolic risk, only a little more than a half of patients were well controlled. Factors associated with poor anticoagulation control were diabetes, labile INR, >6 INR controls and HAS-BLED.

Resumen Objetivo Identificar los factores asociados con el mal control de la anticoagulacion con antagonistas de la vitamina K (AVK) en pacientes con fibrilacion auricular no valvular (FANV) atendidos en consultas de Neurologia y Medicina Interna de Espana. Metodos Estudio transversal, multicentrico, anidado en el estudio ALADIN, de sujetos con FANV, tratados con AVK, atendidos en consultas de Medicina Interna o Neurologia de Espana. El grado de control de la anticoagulacion se estudio mediante el metodo directo y el de Rosendaal, considerando los 6 meses previos a la inclusion. Resultados De los 1.337 pacientes incluidos en ALADIN, 750 estaban tratados con AVK, con informacion completa sobre el INR de los ultimos 6 meses en 383 pacientes. Las puntuaciones medias del indice de Charlson, CHADS2, CHA2DS2-VASc y HAS-BLED fueron 1,94 ± 1,54; 3,10 ± 1,26; 4,63 ± 1,54 y 2,20 ± 0,90, respectivamente. El 46,2% y el 47,0% de los pacientes presentaban un control adecuado de la anticoagulacion por los metodos directo y Rosendaal, respectivamente. El control inadecuado de la anticoagulacion se asocio por el metodo directo con diabetes (OR: 2,511; IC 95%: 1,144-5,659), antecedentes de INR inestable (OR: 35,371; IC 95%: 15,058-83,083) y la realizacion de > 6 controles en los ultimos 6 meses (OR: 4,747; IC 95%: 2,094-10,759), y por el metodo de Rosendaal, con los antecedentes de INR inestable (p Conclusiones Pese al alto riesgo tromboembolico, solo estaban bien controlados algo mas de la mitad. Los factores asociados al mal control de la anticoagulacion fueron la diabetes, INR inestable, > 6 controles de INR y el HAS-BLED.

En el presente trabajo se hace una evaluación electroquímica variando el pH de un nuevo electrodo modificado con MOF-199, por medio de voltamperometrías cíclicas, el cual presenta respuestas electroquímicas en dos medios con Oxígeno y sin este gas, los Metal Organic Framework son materiales cristalinos formados por la unión de un precursor orgánico y uno inorgánico, estos materiales han tenido grandes aplicaciones en los últimos años en distintas áreas como lo es la adsorción de gases o catálisis, sensores, entre otras. Estos materiales han dado pauta al desarrollo de diversas investigaciones en Química, lo cual permite la aplicación en diversas especialidades de la química como lo es la química analítica, debido a la variedad de propiedades que estos representan, es ahí donde radica la importancia de una amplia investigación en estos compuestos en el área electroquímica.

Most drugs are small molecules because of their attractive pharmacokinetics, manageable development and manufacturing, and effective binding into the concave crevices of bio-macromolecules. Despite these features, they often fall short when it comes to effectively recognizing the surfaces of bio-macromolecules. One way to overcome the challenge of biomolecular surface recognition is to develop small molecules that become self-assembled ligands (SALs) prior to binding. Herein, we report SALs made from 8-aryl-2′-deoxyguanosine derivatives forming precise hydrophilic supramolecular G-quadruplexes (SGQs) with excellent size, shape, and charge complementarity to G-quadruplex DNA (QDNA). We show that only those compounds forming SGQs act as SALs, which in turn differentially stabilize QDNAs from selected oncogene promoters and the human telomeric regions. Fluorescence resonance energy-transfer melting assays are consistent with spectroscopic, calorimetric, and light scattering studies, showing the formation of a “sandwichlike” complex QDNA·SGQ·QDNA. These results open the door for the advent of SALs that recognize QDNAs and potentially the surfaces of other bio-macromolecules such as proteins.

Nanoflowers (NFs) are flowered-shaped particles with overall sizes or features in the nanoscale. Beyond their pleasing aesthetics, NFs have found a number of applications ranging from catalysis, to sensing, to drug delivery. Compared to inorganic based NFs, their organic and hybrid counterparts are relatively underdeveloped mostly because of the lack of a reliable and versatile method for their construction. We report here a method for constructing NFs from a wide variety of biologically relevant molecules (guests), ranging from small molecules, like doxorubicin, to biomacromolecules, like various proteins and plasmid DNA. The method relies on the encapsulation of the guests within a hierarchically structured particle made from supramolecular G-quadruplexes. The size and overall flexibility of the guests dictate the broad morphological features of the resulting NFs, specifically, small and rigid guests favor the formation of NFs with spiky petals, while large and/or flexible guests promote NFs with wide petals. The results from experiments using confocal fluorescence microscopy, and scanning electron microscopy provides the basis for the proposed mechanism for the NF formation.

Immunogenicity of DNA vaccines can be efficiently improved by adding adjuvants into their formulations. In this regard, the application of nano- and microparticles as vaccines adjuvants, or delivery systems, provides a powerful tool in designing modern vaccines. In the present study, we examined the role of “Supramolecular Hacky Sacks” (SHS) particles, made via the hierarchical self-assembly of a guanosine derivative, as a novel immunomodulator for DNA plasmid preparations. These plasmids code for the proteins HIV-1 Gag (pGag), the wild-type vaccinia virus Western Reserve A27 (pA27L), or a codon-optimized version of the latter (pOD1A27Lopt), which is also linked to the sequence of the outer domain-1 (OD1) from HIV-1 gp120 protein. We evaluated the enhancement of the immune responses generated by our DNA plasmid formulations in a murine model through ELISpot and ELISA assays. The SHS particles increased the frequencies of IFN-γ-producing cells in mice independently immunized with pGag and pA27L plasmids. Moreover, the addition of SHS to pGag and pA27L DNA plasmid formulations enhanced the production of IFN-γ(Th1-type) over IL-4 (Th2-type) cellular immune responses. Furthermore, pGag and pA27L plasmids formulated with SHS, triggered the production of antigen-specific IgG in mice, especially the IgG2a isotype. However, no improvement of either of those adaptive immune responses was observed in mice receiving pOD1A27Lopt+SHS. Here, we demonstrated that SHS particles have the ability to improve both arms of adaptive immunity of plasmid coding “wild-type” antigens without additional strategies to boost their immunogenicity. To the best of our knowledge, this is the first report of SHS guanosine-based particles as DNA plasmid adjuvants.

To identify factors associated with poor anticoagulation control with vitaminK antagonists (VKA) among outpatients with nonvalvular atrial fibrillation (NVAF) attended in Neurology and Internal Medicine in Spain.Cross-sectional and multicenter study, from the ALADIN database, of outpatients with NVAF treated with VKA and attended in Internal Medicine and Neurology in Spain. Rates of anticoagulation control were determined with the direct and Rosendaal methods, considering data from the 6months before the inclusion.Out of 1,337 patients included in the ALADIN study, 750 were taking VKA, and complete information about INR values in the last 6months was available in 383 patients. Mean scores of Charlson Index, CHADSDespite the high thromboembolic risk, only a little more than a half of patients were well controlled. Factors associated with poor anticoagulation control were diabetes, labile INR,6INR controls and HAS-BLED.

There is a broad semantic network of aging stereotypes; where different concepts and their measurement are confused: personal stereotypes, self-stereotypes and self-perception of aging.First, we analyze the translated version of the Image of Aging Scale (IAS) measurement model through exploratory and confirmatory factor analysis, with two representative sub-samples of the Spanish population aged over eighteen (N = 1,105) and in a sample of gerontologists and geriatricians (N = 325). Second, in an effort to disentangle the theoretical relationships between personal stereotypes, self-stereotypes and self-perception of aging, both the IAS (with different instructions) and Lawtonrsquo;s 5-item scale were administered to a representative sample of Spanish people over 50.Our results indicate that the Spanish version of the IAS has a similar psychometric structure to that proposed by the authors. Furthermore, the factorial structure (equal form and metric invariance) is replicated in both samples, but latent means and factor correlations were higher in the professional group.We discuss Levyrsquo;s theoretical assumptions about personal-stereotypes and the self-stereotype measured with IAS and their relationship to self-perception of ageing.

We report the synthesis and self-assembly of two lipophilic 2′-deoxyguanosine (G) derivatives whose fluorescence intensity is modulated by self-assembly into supramolecular G-quadruplexes (SGQs). Whereas both derivatives self-assemble isostructurally, one shows up to 100% emission enhancement while the other shows an initial enhancement, followed by 10% quenching. Thus, the rotational restrictions resulting from self-assembly are enough to induce significant changes in emission, but it is critical to consider the specific interactions between fluorophores since they will determine the ultimate emission signature. These findings could open the door to the development of luminescent supramolecular sensors and probes.

Self-assembly is a powerful tool for the construction of complex nanostructures. Despite advances in the field, the development of precise self-assembled structures remains a challenge. We have shown that, in the presence of suitably sized cations like K(+), 8-aryl-2'-deoxyguanosine (8ArG) derivatives self-assemble into sets of coaxially stacked planar tetramers, which we term supramolecular G-quadruplexes (SGQs). Previously, we reported that, when the 8-aryl group is a phenyl ring with a meta-carbonyl group, the resulting supramolecule is a hexadecamer, which is remarkably robust as illustrated by its isostructural assembly in both organic and aqueous environments. We report here a detailed three-dimensional structure of the SGQs formed by lipophilic, and hydrophilic, 8ArG derivatives with either 8-(meta-acetylphenyl), 8-(para-acetylphenyl), or 8-(meta-ethoxycarbonylphenyl) groups. The chirality and close contacts between the subunits impose different levels of steric and electrostatic constraints on opposite sides of the tetrads, which determine their preferred relative orientation. The balance between attractive noncovalent interactions juxtaposed with repulsive steric and electrostatic interactions explains the high cooperativity, fidelity, and stability of these SGQs. These structural studies, together with titration experiments and molecular dynamics simulations, provide insight into the mechanism of formation of these SGQs.

Herein we describe the construction of hexadecameric self-assembled dendrimers (SADs) using a series of dendronized 8-(m-acetylphenyl)-2′-deoxyguanosine (mAG) subunits. The azido-substituted mAG subunits were covalently linked to alkynyl polyester dendrons using a copper-catalyzed 1,3-dipolar cycloaddition reaction. Discrete SADs are formed with high fidelity and thermal stability even with the increased steric hindrance offered by the dendrons.

Novel base-modified G-analogues act as self-assembled ionophores for various metal cations. Their extracting efficiency can be modulated by the presence and substitution pattern of a functionalized phenyl group that replaces the H8 in the guanine base.

We describe precise supramolecules that enable evaluating the effective hydrophobicity of amphiphilic or “patchy” nanoglobular systems. These supramolecules exhibit the Lower Critical Solution Temperature (LCST) phenomenon, which provides a quantitative measure of their effective hydrophobicity. Specifically, two isomeric 8-aryl-2′-deoxyguanosine derivatives, with a transposed pair of methylene groups, self-assemble into hexadecameric nanoglobular supramolecular G-quadruplexes (SGQs) showing large differences in their transition temperatures as determined by turbidity and differential scanning calorimetry studies. Molecular modeling studies suggest that the differential clustering of the hydrophobic patches on the surface is responsible for the striking differences between the two isomeric supramolecules.

Thermoresponsive systems are attractive due to their suitability for fundamental studies as well as their practical uses in a wide variety of applications. While much progress has been achieved using polymers, alternative strategies such as the use of well-defined nonpolymeric supramolecules are still underdeveloped. Here we report three 8-aryl-2'-deoxyguanosine derivatives (8ArGs) that self-assemble in aqueous media into precise thermoresponsive supramolecular G-quadruplexes (SGQs). We report the synthesis of such derivatives, studies of their isothermal self-assembly, and the thermally induced assembly to form higher-order meso-globular assemblies we term supramolecular hacky sacks (SHS). The lower critical solution temperature (LCST) that indicates the formation of the SHS was modulated by changing (a) intrinsic parameters (i.e., structure of the 8ArGs); (b) extrinsic parameters such as the salt used to promote the formation of the SGQ; and (c) supramolecular parameters such as the coassembly different 8ArGs to form heteromeric SGQs. Changes in the intrinsic parameters lead to LCST variations in the range of 28-59 °C. Modulating extrinsic parameters such as replacing KI with KSCN abolishes the thermoresponsive phenomenon whereas changing the cation from K(+) to Na(+) or adjusting the pH (in the range of 6-8) has negligible effects on the LCST. Modulating supramolecular parameters results in transition temperatures that are intermediate between those obtained by the respective homomeric SGQs, although the specific proportions of the subunits are critical in determining the reversibility of the process. Given the extensive applications of thermoresponsive polymers, the nonpolymeric supramolecular counterparts presented here may represent an attractive alternative for fundamental studies and biorelevant applications.

Supramolecular G-quadruplexes (SGQs) are formed via the cation promoted self-assembly of guanine derivatives into stacks of planar hydrogen-bonded tetramers. Here, we present results on the formation of SGQs made from the 8-(m-acetylphenyl)-2′-deoxyguanosine (mAGi) derivative in the presence of various mono- and divalent cations. NMR and HR ESI-MS data indicate that varying the cation can efficiently tune the molecularity, the fidelity and stability (thermal and kinetic) of the resulting SGQs. The results show that, parallel to the previously reported potassium-templated hexadecamer (mAGi16·3K+), Na+, Rb+ and NH4+ also promote the formation of similar supramolecules with high fidelity and molecularity. In contrast, the divalent cations Pb2+, Sr2+ and Ba2+ template the formation of octamers (mAGi8), with the latter two inducing higher thermal stabilities. Molecular dynamics simulations for the hexadecamers containing monovalent cations enabled critical insights that help explain the experimental observations.

(Chemical Equation Presented) Controlling the properties of self-assembled supramolecules via intrinsic parameters (i.e., structural information in the subunits) enables the reliable construction of assemblies of well-defined size and composition. Here we show that an optimum balance between repulsive (e.g., steric) and attractive (e.g., Ï?-Ï?, dipole-dipole) noncovalent interactions between subunits of a lipophilic 8-(3-pyridyl)-2â?²-deoxyguanosine derivative enables the high fidelity formation of a stable and discrete self-assembled dodecamer. In contrast, the isosteric 8-phenyl-2â?²- deoxyguanosine derivative assembles into an octamer because it cannot engage in additional dipole-dipole interactions. Adding dodecamers to a supramolecular construction toolbox, already containing octamers and hexadecamers made from other 8-aryl-2â?²-deoxyguanosine derivatives, should enable the preparation of a wide variety of self-assembled nanostructures where the size and the number of functional elements can be precisely fine-tuned for specific applications. © 2009 American Chemical Society.

Photoirradiation of a hexadecameric supramolecular G-quadruplex leads to a diastereoselective [2 + 2] cyclodimerization of half of its constituent subunits, which in turn shifts the equilibrium toward the formation of a precise heteromeric octamer.

We have developed the 8-(m-acetylphenyl)-2'-deoxyguanosine (mAG) scaffold for the self-assembly of supramolecules in water and for the synthesis of self-assembled dendrimers (SADs) in organic media. Previously, reported mAG assemblies showed promising characteristics for the construction of SADs. Yet, none of these SADs had large enough dendrons to reach a fractal geometry characteristic of high-generation dendrimers. Here we present the synthesis as well as the molecular and supramolecular characterization of a fourth-generation hydrophilic self-assembled hexadecameric dendrimer [mAGD(4)(OH)(16)](16)·3KI (3(16)) with a size and shape akin to those of globular proteins. The diameter of 3(16) (5.0 nm) was measured by pulsed field gradient NMR and dynamic light scattering experiments, which enabled the construction of a computer-generated molecular model. This SAD represents an attractive platform for biomedical applications due to its water solubility, discreteness, well-defined structure, thermal stability (T(m) = 68 °C), and functional core.

An 8-(phenyl)-2′-deoxyguanosine derivative self-assembles in aqueous media into discrete hexadecamers that further self-assemble above 32 °C into microglobules that encapsulate the drug doxorubicin.

We have previously reported that 8-phenyl-2'-deoxyguanosine derivatives (8PhGs) are able to extract metal cations from an aqueous phase into an organic phase. Herein, we report on the ability of 8PhGs to transport metal cations across a bulk lipophilic liquid membrane. The experiments were performed using lithium, sodium, potassium and strontium picrate salts with the parent lipophilic Gi, two isomeric 8PhG derivatives, cis-dicyclohexano-18-crown-6 (DC18C6) and [222] cryptand as reference compounds. The relative amounts of the picrate salts were measured by UV spectroscopy in both the source phase and the receiving phase over a period of 24h. The results show that the transport efficiency of the self-assembled ionophores formed by 8PhGs is either similar or superior to that of DC18C6, and in all but one case higher than the parent compound Gi. The varying efficiencies between the derivatives can be attributed to the stability (kinetic and thermodynamic) and the different molecularities of the supramolecules formed by these 8PhGs. The ease of the synthesis of 8PhGs, their anion-independent assembly and the fact that the transport efficiency can be modulated as a function of the structure of the 8PhGs bode well for the use of such compounds in the development of novel antimicrobial agents and cation-sensing devices. © 2010 Taylor & Francis.

Studies on the different congeners of the softball were undertaken to explore structural variants for enantioselective encapsulation. Two different spacer elements in the monomeric subunit render the dimeric softball chiral although the monomer itself is achiral. The dimers represent capsules with dissymmetric cavities with volumes ranging from 190 to 390 A3. The cavities are distorted spheres, and asymmetric guests, such as naturally occurring terpenes, generally prefer one enantiomer of the capsule to its mirror image. The selectivities are moderate (up to 4:1). The complexation studies show that the host capsules are flexible enough to arrange themselves comfortably around a guest but still maintain enough rigidity to be influenced by the occupancy of a chiral guest. The enantiomeric capsules can interconvert (racemize) by dissociation and recombination of their subunits.

We describe the synthesis of 8-heteroaromatic-2'-deoxyguanosine analogues using Suzuki-Miyaura or Stille conditions. Unprotected and protected 8-bromo-2â?²-deoxyguanosine was coupled with commercially available heteroarylboronic acids or the trialkyltin derivatives of 2-pyridylbromides either with or without microwave irradiation in good yields.

Here we show 2'-deoxyguanosine derivatives that self-assemble in aqueous media into discrete supramolecular hexadecamers and exhibit the lower critical solution temperature (LCST) phenomenon. Spectroscopic, calorimetric, and electron microscopy studies support the fact that above the transition temperature (T(t)) the supramolecules further assemble into nanoscopic spherical globules of low polydispersity. Furthermore, the T(t) can be tuned to higher values by the addition of a more hydrophilic derivative. These findings uncover a new paradigm in the development of smart thermosensitive materials with properties and applications complementary to those of polymers.

Here we show the reversible high fidelity switching between two discrete self-assembled supramolecules made from a lipophilic 8-phenyl-2�- deoxyguanosine derivative induced by an indirect solvent effect. A hexadecameric supramolecule containing four stacked tetramers is formed in acetonitrile aided by higher potassium concentrations. When the amount of weakly solvated potassium decreases, due the lower activity of potassium iodide in chloroform, an octamer is formed after the dissociation of the two outer tetramers in the hexadecamer. The switching process results from an unprecedented subtle interplay between the activity of potassium iodide and the steric crowding within the self-assembled structure. Besides the possible applications in nanoconstruction, this phenomenon sheds light into the mechanism of formation of self-assembled supramolecules made from guanosine derivatives. Copyright © 2009 American Chemical Society.

Guanine and G-rich oligonucleotides are known to self-assemble in the presence of a variety of cations to form higher ordered structures known as Gquadruplexes. We have synthesized a library of 8-aryl/heteroaryl-2'-deoxyguanosine derivatives (8ArGs) that are also able to self-assemble into quadruplex structures. We demonstrate that the properties of such quadruplexes can be modulated by the nature of the groups attached to the guanine base. These supramolecules are potentially useful in the development of self-assembled nanodevices.

a b s t r a c t Familial Mediterranean fever (FMF) is a rare disease in our environment, which is passed down through families by means of an autosomal-recessive manner. Only few patients show pericardial effusion during the episode. We present the case of a 23-year-old woman with pericardial effusion and recurrent attacks of fever, abdominal pain and pericarditis. We arrived at the diagnosis of FMF by performing genetic studies.

(Chemical Equation Presented) The synthesis and self-assembling properties of 8-aryl-2'-deoxyguanosine derivatives are described. Our studies suggest that a properly placed acetyl group can increase the stability and specificity of the resulting G-quadruplex supramolecules by enhancing noncovalent interactions such as hydrogen bonds and Ï?-stacking.

Studies on the different congeners of the softball were undertaken to explore structural variants for enantioselective encapsulation. Two different spacer elements in the monomeric subunit render the dimeric softball chiral although the monomer itself is achiral. The dimers represent capsules with dissymmetric cavities with volumes ranging from 190 to 390 Å3. The cavities are distorted spheres, and asymmetric guests, such as naturally occurring terpenes, generally prefer one enantiomer of the capsule to its mirror image. The selectivities are moderate (up to 4:1). The complexation studies show that the host capsules are flexible enough to arrange themselves comfortably around a guest but still maintain enough rigidity to be influenced by the occupancy of a chiral guest. The enantiomeric capsules can interconvert (racemize) by dissociation and recombination of their subunits.

Reversibly self‐assembling host–guest complexes of the softball type are characterized by electrospray ionization mass spectrometry. Quaternary ammonium ions serve simultaneously as guests and ion labels. Isotope pattern analysis, inclusion of labeled guests, heterodimer experiments, size and shape dependence, and collision‐induced fragmentation reveal that the capsular structure of these hydrogen‐bonded complexes is retained in the gas phase with the guests inside their cavity. The results parallel findings from solution‐phase NMR experiments and show that the guests are encapsulated inside the cavity. These results also demonstrate the value of mass spectrometry for high‐order structural examination of supramolecular architecture.

We report the self-assembly of a hydrophilic 8-(m-acetylphenyl)-2′-deoxyguanosine (mAG) derivative into a discrete and thermally stable hexadecameric supramolecule in aqueous media. We demonstrate that this hexadecamer is isostructural to the one formed by a related lipophilic derivative in organic media. This mAG moiety represents a rare example of a small-molecule recognition motif that is capable of assembling isostructurally and with high fidelity in both organic and aqueous media.

We thank the Skaggs Research Foundation and the National Institutes of Health for support. We also thank Dr. Tomas Szabo for advice on the synthesis of protected glycolurils. Administración de Fomento Económico of Puerto Rico provided fellowship support to J.M.R. The Ministerio de Educación y Cultura of Spain provided fellowship support to T.M.