Synthesis and Gelling Abilities of Polyfunctional Cyclohexane-1,2-dicarboxylic Acid Bisamides: Influence of the Hydroxyl Groups.

New enantiomerically pure C16-alkyl diamides derived from trihydroxy cyclohexane-1,2-dicarboxylic acid have been synthesized from (-)-shikimic acid. The hydroxyl groups in these compounds are free or, alternatively, they present full or partial protection. Their gelling abilities towards several solvents have been tested and rationalized by means of the combined use of Hansen solubility parameters, scanning electron microscopy (SEM), and circular dichroism (CD), as well as computational calculations. All the results allowed us to account for the capability of each type of organogelator to interact with different solvents and for the main mode of aggregation. Thus, compounds with fully protected hydroxyl groups are good organogelators for methanol and ethanol. In contrast, a related compound bearing three free hydroxyl groups is insoluble in water and polar solvents including alcohols but it is able to gelate some low-polarity solvents. This last behavior can be justified by strong hydrogen bonding between molecules of organogelator, which competes advantageously with polar solvent interactions. As an intermediate case, an organogelator with two free hydroxyl groups presents an ambivalent ability to gelate both apolar and polar solvents by means of two aggregation patterns. These involve hydrogen bonding interactions of the unprotected hydroxyl groups in apolar solvents and intermolecular interactions between amide groups in polar ones.

Studies on Cycloalkane-Based Bisamide Organogelators: A New Example of Stochastic Chiral Symmetry-Breaking Induced by Sonication.

Enantiomerically pure C16 -alkyl amides derived from cis and trans cycloalkane-1,2-dicarboxylic acids, respectively, have been synthesized and their behavior as organogelators has been investigated. These compounds include cis/trans diastereomeric cyclobutane and cyclohexane derivatives with the aim to explore the influence of the ring size as well as the relative configuration in their hierarchical self-assembly to form gels. High resolution 1 H NMR spectroscopy studies allowed the determination of the dynamics of the gelation process in [D8 ]toluene and the sol-gel transition temperature. The morphology and size of the aggregates have been investigated and results have shown that, in the case of cyclobutane derivatives, the cis/trans stereochemistry is not relevant for the gelation behavior and the properties of the soft-materials obtained, but it is remarkable for cyclohexane diamides, which are better organogelators. The four compounds produce chiral aggregates despite that two of them are meso achiral molecules. We show herein that this fact is an example of stochastic symmetry breaking induced by sonication. The self-assembly of these molecules has been modelled providing information and support about the structure and the chirality of the aggregates.

Synthesis of Spironucleosides: Past and Future Perspectives.

Spironucleosides are a type of conformationally restricted nucleoside analogs in which the anomeric carbon belongs simultaneously to the sugar moiety and to the base unit. This locks the nucleic base in a specific orientation around the N-glycosidic bond, imposing restrictions on the flexibility of the sugar moiety. Anomeric spiro-functionalized nucleosides have gained considerable importance with the discovery of hydantocidin, a natural spironucleoside isolated from fermentation broths of Streptomyces hygroscopicus which exhibits potent herbicidal activity. The biological activity of hydantocidin has prompted considerable synthetic interest in this nucleoside and also in a variety of analogues, since important pharmaceutical leads can be found among modified nucleoside analogues. We present here an overview of the most important advances in the synthesis of spironucleosides.

Mechanical intestinal obstruction secondary to congenital diaphragmatic hernia in an adult. Report of a case.

We present a case of congenital diaphragmatic hernia diagnosed in an adult. It is a kind of exceptional pathology outside the pediatric age with few cases reported in the literature. Its presentation is unusual, especially in the form of mechanical intestinal obstruction, requiring surgical treatment.

Usefulness of triglyceride levels in pleural fluid.

The determination of pleural fluid triglycerides (PF-TRIG) is useful in the diagnosis of chylothorax, but its diagnostic value for other causes of pleural effusions is unknown. The aim of this study was to evaluate the usefulness of PF-TRIG in the diagnosis of other pleural effusions and investigate the origin of their increase in these fluids. We studied 390 pleural effusions (75 tuberculous, 107 neoplastic, 39 parapneumonic, 30 miscellaneous, 42 idiopathic, and 97 transudates). The correlation was analyzed with the PF-TRIG values as the dependent variable and serum triglycerides (S-TRIG) and the pleural fluid/serum protein ratio (PF/S PROT ratio) as independent variables. The PF-TRIG was significantly higher in exudates. The sensitivity of PF-TRIG for identifying exudates was 84.3%, specificity 61.9%. The correlation between PF-TRIG and S-TRIG was significant in the exudates and in the total pleural effusions. There was a significant correlation between PF-TRIG and S-TRIG and capillary permeability, which worsened when looking at the transudates and exudates separately. No correlations were found between the PF-TRIG and the number of red cells and white cells in any of the groups. Except for diagnosing a chylothorax, the determination of triglycerides in pleural fluid does not appear to be justified. The cause of the increase in PF-TRIG in exudates could not be established because the correlations obtained were insufficient to be able to predict PF-TRIG values from their serum values and the measurement of capillary permeability.

[Estimation of the retinal microvascular calibre in hypertensive patients with the snakes semiautomatic model]. / Determinación del calibre vascular retiniano en hipertensos con un método semiautomático basado en el modelo de snakes.

BACKGROUND AND OBJECTIVE: Early alterations in retinal microcirculation are observed in most hypertensive patients seen in daily practice and the European guidelines consider it is necessary an objective method to quantify these alterations. We have previously described a semi-automatic computerized system to evaluate the calibre of retinal blood vessels that has shown high sensitivity and specificity to calculate the arteriovenous ratio (AVR), though with limitations. We describe a method based on the snakes model to calculate the arteriovenous ratio. PATIENTS AND METHOD: We had compared it with the previously reported lineal method, and we have analyzed 173 digital photographs from 96 hypertensive patients, most of them receiving treatment. Photos were made in two hospitals (A Coruña: 66 and Santiago de Compostela: 107), and were analysed by the same people in each Centre, by the lineal and snake method. RESULTS: We have observed that the arithmetic mean and the differences in AVR between both methods were minimal and showed a normal distribution. Cronbach statistics was 0.974 and intraclass correlation coefficient 0.949 (p<0.001), for the images from Santiago and 0.923 with an intraclass correlation coefficient of 0.857 (p<0.001) for the images from A Coruña. CONCLUSION: This semiautomatic method to calculate the AVR ratio has a high sensitivity and a greater specificity than previous method, and the correlation between the results obtained with both is excellent.

Searching the conformational space of cyclic beta-amino acid peptides.

There is an increasing interest in the secondary structure of beta-amino-acid-containing peptides, since these compounds exhibit an intrinsic propensity to form stable folds even for short peptides, a feature that is rarely observed in alpha-amino-acid-containing peptides. In this work, we use a multiple trajectory molecular dynamics approach to study a panel of cyclic beta-amino-acid-containing peptides with a variety of motifs that differ in the ring size, ring substituents, and terminal protecting groups. We find a reasonable agreement between the predicted and the experimentally observed structures, in spite of the simple solvent representation used, indicating that in most cases the folding proceeds energetically downhill and it is driven to a great extent by structural preferences coded in the internal degrees of freedom, a result supported by our energy partition analysis. Our results also show that when the N-terminal end is unprotected, it is likely to be charged in a protic polar solvent. In that case, we find that only a molecular dynamics simulation with an "all atom" solvent representation is capable of reproducing the experimentally observed secondary structure of the peptide. Finally, the time evolution analysis of the hydrogen-bond-induced turns as well as of the root-mean-square deviation from the observed structure indicates that some peptides could have a higher intrinsic flexibility than others, within a given fold, a result that correlates to some degree with our molecular mechanics energy analysis.

Cholesterol in pleural exudates depends mainly on increased capillary permeability.

Pleural fluid (PF) cholesterol is a useful parameter to differentiate between pleural transudates and exudates, although the pathophysiologic mechanisms for its increase in exudates are not fully understood. We aim to elucidate the cause of this increase by analyzing the levels of cholesterol-high-density lipoproteins (HDLs), low-density lipoproteins (LDLs), apolipoprotein A (ApoA), and apolipoprotein B (ApoB)-in PF and blood as well as the number of leucocytes and red cells in the PF. We studied 259 patients with pleural effusion (57 transudates and 202 exudates). The correlations of the pleural and serum (S) levels of these parameters were analyzed, with the pleural cholesterol fractions as the dependent variables and their levels in blood and the pleural/serum protein ratio (P/S prot ratio) as the independent variables. The pleural fluid cholesterol levels (PFCHOL) correlated with their blood levels and the capillary permeability (r=0.885). No significant differences were found between the percentage of LDL, with regard to total cholesterol in the serum [SCHOL], and the same percentage in the exudates, between the PF/S LDL ratio (0.46) and the PF/S CHOL ratio (0.48), or between the PF/S ApoB ratio and the PF/S LDL ratio. The percentage of PF cholesterol bound to HDL and LDL was significantly higher (91.9%) than in the blood (90%). No significant correlations were found between any of the lipids studied and the number of erythrocytes and leucocytes. In conclusion, the PFCHOL may be predicted from the SCHOL, and the capillary permeability may be reflected by the PF/S prot ratio.

Eosinofilia en enfermos de uveitis anterior aguda / Eosinophilia in patients presenting with acute anterior uveitis

Se realizo un estudio prospectivo en 50 enfermos de uveitis anterior aguda con el proposito de describir en los mismos la eosinofilia ocular y en sangre. En el estudio se corrobora que en la totalidad de los casos con sensibilidad alergica demostrada, aparece eosinofilia ocular y en sangre. Sin embargo, en aquellos en que la etiologia fue una colecistopatia con giardiasis cronica asociada, aparece eosinofilia ocular en el 79,0 por ciento. Es destacable que en los pacientes cuya causa fue un poco septico,toxoplasmosis o enfermedad autoinmune, no se contato eosinofilia. En dicha investigacion se valora la importancia del eosinofilo en los pacientes con uveitis anterior aguda, cuya causa probable es alergica, infecciosa o autoinmunitaria

Eosinofilia en pacientes portadores de uveítis anterior aguda / Eosinophilia in patients with acute anterior uveitis

Se realizó un estudio prospectivo de 50 pacientes portadores de uveítis anterior aguda con el propósito de confirmar eosinofilia y en sangre. En quienes el factor causal fue una colecistopatía con giardiasis crónica concomitante, se registró eosinofilia ocular en 70 por ciento de los casos. En quienes la causa fue un foco séptico, toxoplasmosis o enfermedad autoinmune, no se comprobó eosinofilia

Comportamiento inmunológico en 50 pacientes diagnósticados con uveitis anterior aguda / Immunologic behaivior in 50 patients with diagnosis of acute anterior uveitis

Se realizó un estudio prospectivo en 50 pacientes que presentaban uveitis anterior aguda con el propósito de describir el comportamiento inmunológico en los mismos. Según nuestros estudios, los pacientes con base alérgica tienen una cierta predisposición a padecer la enfermedad y su intensidad es mayor. Sin embargo, la positividad en los resultados de las pruebas inmunoalérgicas se constatan en pacientes con uveítis anterior aguda donde las enfermedades asociadas modifican las pruebas, ya sea de causa probable o no. Recomendamos continuar estudios en los pacientes con antecedentes alérgicos, con el fin de extremar su atención

Comportamiento inmunológico en 50 pacientes postadores de uveítis anterior aguda / Immunologic behavior in 50 patients with acute uveitis anterior

Se realizó un estudio prospectivo en 50 pacientes portadores de uveitis anterior aguda con el propósito de describir el comportamiento inmunológico en los mismos. Según nuestros estudios, los papcientes con base alérgica tienen cierta predisposición a padecer esta enfermedad y con intensidad mayor. Sin embargo, la positividad en los resultados de las pruebas inmunoalérgicas se constatan en pacientes portadores de uveitis anterior aguda donde las patologías asociadas modifican las pruebas, ya sea la etiología probable o no. Recomendamos continuar estudios en los pacientes con antecedentes alérgicos, conel fín de extremar su atención