Synthesis and characterization of new tail-to-tail dimers of bile acids with different spacers

The 13th International Electronic Conference on Synthetic Organic Chemistry session Polymer and Supramolecular ChemistryNew dimeric steroid-based surfactants derived from 3α,7α,12α-trihydroxy-5β- cholan-24-amine (steroid residue) and isophthalic acid, 5,5'-biisobenzofuran-1,1',3,3'- carboxylic acid and succinic acid (spacers) were synthesized and structurally characterized by NMR techniques. The first spacer was also employed to synthesize the dimer corresponding to the 3α,12α-dihydroxy-5β-cholan-24-amine residue. In all cases the steroid residues are tail-to-tail linked through amide bonds with the spacersAuthors thank the Ministerio de Ciencia y Tecnología (Project MAT2004-04606) and the Xunta de Galicia (PGIDIT05PXIC26201PN) for financial suppor

Theoretical calculations on conformations of bile-acid based dimers. Interactions with ibuprofen

The 13th International Electronic Conference on Synthetic Organic Chemistry session Polymer and Supramolecular ChemistryAn AM1 semiempirical method (Gaussian 03) was used to perform molecular structure optimizations in gas phase of two tail-to-tail bile acid-based dimers by an isophthalic acid bridge. The method was also used to study the interactions with the potential guest ibuprofen with the idea of applicative resultsAuthors thank the Ministerio de Ciencia y Tecnología (Project MAT2004-04606) and the Xunta de Galicia (PGIDIT05PXIC26201PN) for financial suppor

Synthesis and Characterization of a New Gemini Surfactant Derived from 3a,7a,12a-trihydroxy-5ß-cholan-24-amine (Steroid Residue) and Ethylenediamintetraacetic Acid (Spacer)

The 12th International Electronic Conference on Synthetic Organic Chemistry session Supramolecular ChemistryA new gemini steroid surfactant derived from 3a,7a,12a-trihydroxy-5ß-cholan-24-amine (steroid residue) and ethylenediamintetraacetic acid (spacer) was synthesized and characterized in aqueous solution by surface tension measurements and fluorescence intensity of pyrene. These techniques evidence the existence of a threshold concentration, cac, below which a three layers film is formed at the air-water interface. At high concentrations, the intensity ratio of the vibronic peaks of pyrene, I1/I3, (= 0.81) is very close to published values for sodium cholate micelles, indicating that the probe is located in a region with a very low polarity and far from waterThe authors from USC thank the Ministerio de Ciencia y Tecnología (Project MAT2004-04606) and Xunta de Galicia (PGIDIT05PXIC26201PN) for financial suppor

Complexation of 3α,7α,12α-trihydroxy-5β-cholan-24-amine by β- and γ-cyclodextrins

The 13th International Electronic Conference on Synthetic Organic Chemistry session Polymer and Supramolecular ChemistryThe binding constants, standard molar enthalpy, Gibbs free energy, and entropy changes were determined for the formation of inclusion complexes between 3α,7α,12α- trihydroxy-5β-cholan-24-amine, C24NH2, and β-cyclodextrin and γ-cyclodextrin. The stoichiometry of both complexes is 1:1 in agreement with previously reported results for other trihydroxy bile salts. The equilibrium constant values for the formation of the inclusion complex are similar as well. The structure of the C24NH2/γ-cyclodextrin complex was studied by ROESY experiments. These results suggest that B, C and Drings of the steroid skeleton, as well as the side chain, interact with the cyclodextrin cavity, while the A ring of the steroid nucleus remains outside the cavityThe authors from USC thank the Ministerio de Ciencia y Tecnología (Project MAT2004-04606) and Xunta de Galicia (PGIDIT05PXIC26201PN) for financial suppor

Complexation of adamantyl derivatives by a β–cyclodextrin dimer.

The 13th International Electronic Conference on Synthetic Organic Chemistry session Polymer and Supramolecular ChemistryThe binding constants, standard molar enthalpy, Gibbs free energy, and entropy changes were determined for the formation of complexes between adamantyl derivatives and a β-cyclodextrin dimer. It is concluded that, within experimental error, the two cyclodextrin residues in the dimer behave independent to each other when complexing the adamantyl derivativesThe authors from USC thank the Ministerio de Ciencia y Tecnología (Project MAT2004-04606) and Xunta de Galicia (PGIDIT05PXIC26201PN) for financial suppor

Supramolecular polymer formed by ditopic cyclodextrin and ditopic adamantane derivatives

The 12th International Electronic Conference on Synthetic Organic Chemistry session Supramolecular ChemistryNovel host-guest supramolecular copolymers have been prepared from a ß-cyclodextrin (binded to ethylenediamintetraacetic acid, EDTA) dimer and a ditopic guest with two adamantyl groups bound to pyromellitic acid. Molecular weight and molecular size were determined from static and dynamic light scattering measurements (SLS and DLS, respectively). The analysis of results suggests that the supramolecular polymer adopts a shruck structure with an average molecular weight value of Mn =(1.51±0.02)×104 g·mol-1 (degree of polymerization equal to 5)The authors from USC thank the Ministerio de Ciencia y Tecnología (Project MAT2004-04606) and Xunta de Galicia (PGIDIT05PXIC26201PN) for financial suppor

Host-Guest Supramolecular Dendrimers

The 11th International Electronic Conference on Synthetic Organic Chemistry session Supramolecular ChemistryThe formation of new supramolecular dendrimers from interlocked host/guest unimers is reported. Unimer entities have two host binding sites (ßCD) and two guest binding sites (two adamantly or two p-tert-butylbenzoate moities). Hosts and guest residues are linked through an EDTA bridge. The formation of dendrimer-like (Cayley tree) structures is demonstrated by TEM measurements.The authors from USC thank the Ministerio de Ciencia y Tecnología (Project MAT2004-04606) and Xunta de Galicia (PGIDIT05PXIC26201PN) for financial support. The authors from ‘La Sapienza’ thank the MIUR financial supports (FIRB project RBIN04PWNC and PRIN 2006).We also thank for the Spain-Italy Integrated Action grant

Henoch-Schönlein purpura in northern Spain: clinical spectrum of the disease in 417 patients from a single center

The severity of clinical features and the outcomes in previous series of patients reported with Henoch-Schönlein purpura (HSP) vary greatly, probably due to selection bias. To establish the actual clinical spectrum of HSP in all age groups using an unselected and wide series of patients diagnosed at a single center, we performed a retrospective review of 417 patients classified as having HSP according to the criteria proposed by Michel et al. Of 417 patients, 240 were male and 177 female, with a median age at the time of disease diagnosis of 7.5 years (interquartile range [IQR], 5.3-20.1 yr). Three-quarters of the patients were children or young people aged 20 years or younger (n = 315), and one-quarter were adults (n = 102). The most frequent precipitating events were a previous infection (38%), usually an upper respiratory tract infection, and/or drug intake (18.5%) shortly before the onset of the vasculitis. At disease onset the most common manifestations were skin lesions (55.9%), nephropathy (24%), gastrointestinal involvement (13.7%), joint symptoms (9.1%), and fever (6.2%). Cutaneous involvement occurring in all patients, mainly purpuric skin lesion, was the most common manifestation when the vasculitis was fully established, followed by gastrointestinal (64.5%), joint (63.1%), and renal involvement (41.2%). The main laboratory findings were leukocytosis (36.7%), anemia (8.9%), and increased serum IgA levels (31.7%). The most frequent therapies used were corticosteroids (35%), nonsteroidal antiinflammatory drugs (14%), and cytotoxic agents (5%). After a median follow-up of 12 months (IQR, 2-38 mo), complete recovery was observed in most cases (n = 346; 83.2%), while persistent, usually mild, nephropathy was observed in only 32 (7.7%) cases. Relapses were observed in almost a third of patients (n = 133; 31.9%).In conclusion, although HSP is a typical vasculitis affecting children and young people, it is not uncommon in adults. The prognosis is favorable in most cases, depending largely on renal involvement

Mar Menor: una laguna singular y sensible. Evaluación científica de su estado.

Este libro recopila las aportaciones que equipos de investigación de la Universidad de Murcia, Universidad Politécnica de Cartagena, Instituto Geológico-Minero de España, Universidad de Alicante, el Instituto Español de Oceanografía y otros organismos hicieron en las Jornadas Científicas del Mar Menor, celebradas en diciembre de 2014.La información recogida en este libro se estructura en dos grandes bloques, uno de Biología y Ecología del Mar Menor (capítulos 1 al 8) y otro de Condiciones fisicoquímicas e impacto de actividades humanas en la laguna (capítulos 9 al 14). El primer bloque resume buena parte de los estudios ecológicos realizados en el Mar Menor, que han servido para mejorar su conocimiento y también para cambiar antiguas asunciones sobre la naturaleza y el funcionamiento de estos ecosistemas lagunares (Capítulo 1). El segundo capítulo muestra que esta laguna alberga en zonas someras de su perímetro hábitats fundamentales para mantener y conservar tanto especies migratorias como residentes, que es necesario conocer para paliar el impacto de las actividades humanas que les afectan. En este sentido la reducción de la carga de nutrientes y contaminantes orgánicos e inorgánicos que fluyen hacia el Mar Menor puede ayudar a preservar la laguna en mejores condiciones, bien sea tratando las escorrentías (plantas de tratamiento, humedales artificiales u otras técnicas) y recuperar este agua para uso agrícola o evitar su descarga en la laguna (Capítulo 3). Estas actuaciones serán clave para la conservación de especies emblemáticas como el caballito de mar (Capítulo 4) y reducir el impacto de las proliferaciones masivas de medusas que se producen en la laguna desde 1993 (Capítulo 5). En este mismo sentido los cambios acaecidos en la laguna han favorecido la incursión de invertebrados marinos alóctonos (Capítulo 6) y han afectado a la respuesta de la dinámica poblacional de las aves acuáticas a distintas escalas (Capítulo 7). Para completar este bloque se ofrece una perspectiva histórica de la importancia que ha tenido la investigación sobre acuicultura realizada en esta laguna, que ha servido de base para su gran desarrollo actual (Capítulo 8). El segundo bloque se inicia con una evaluación del origen y evolución del Mar Menor desde el punto de vista geológico, y evidencia su vulnerabilidad ante el deterioro que puede sufrir la desaparición de la barrera de cierre y/o su colmatación (Capítulo 9). En el Capítulo 10 se describe la relevancia que tiene la interacción de los acuíferos del Campo de Cartagena con la laguna, que se produce no sólo a nivel superficial sino también subterráneo. Esta interacción permite el acceso de nutrientes a la laguna, a pesar de la cierta capacidad de depuración de los humedales que le circundan, y también de metales traza por los aportes de residuos mineros (Capítulo 11). De hecho los metales traza están presentes en los sedimentos de la laguna, y su distribución se ha caracterizado en la columna sedimentaria relacionándola con la granulometría y el contenido de materia orgánica del sedimento (Capítulo 12). Posteriormente se describe la entrada de diversos contaminantes orgánicos, incluyendo pesticidas y fármacos a través de la rambla del Albujón, y su distribución estacional en agua y sedimento de la laguna (Capítulo 13). Este segundo bloque finaliza con el Capítulo 14 en el que se describe la bioacumulación de hidrocarburos aromáticos policíclicos, pesticidas y fármacos en moluscos y peces del Mar Menor, así como los efectos biológicos que la carga contaminante que accede a través de la rambla del Albujón produce en los organismos que allí habitan. El libro concluye con un breve epílogo redactado por los editores de este libro