Casuística de Hidatidosis humana y tratamiento con medicación antiparasitaria

En la provincia de Catamarca la hidatidosis, producida por el cestodo Echinococcus granulosus, es una parasitosis endémica y se encuentra distribuida en los 16 departamentos que integran la provincia, donde fueron identificadas 3 cepas del parásito, cepa Camello (G6), cepa Vaca (G5) y cepa Oveja (G1). La importancia sanitaria de esta enfermedad reside en la alta morbilidad que produce, además de ocasionar pérdidas económicas concomitantes. La prevalencia está reducida por un fuerte subregistro debido a la existencia de pacientes diagnosticados en otras provincias, o en algunas clínicas privadas que no los comunican

Structural features of a cationic gemini surfactant at full hydration investigated by energy dispersive X-ray diffraction

Energy dispersive X-ray diffraction (EDXD) measurements were conducted on fully hydrated samples of the cationic gemini surfactant (2S,3S)-2,3-dimethoxy-1,4-bis(N-hexadecyl-N,N-dimethylammonium)butane dibromide, SS, as a function of temperature. The surfactant molecules self-assemble into multilamellar vesicles with a well-defined d-spacing which decreases as temperature increases. The derived structural parameters, such as bilayer thickness, size of the water region interbilayer, number of water molecules per surfactant molecule reveal reduced bilayer fluctuations, as a function of increasing temperature, consistent with the observed reduction of the water layer. (C) 2004 Elsevier B.V. All rights reserved

The Structure of Gemini Surfactants Self-Assemblies Investigated by Energy Dispersive X-ray Diffraction

Solid-supported multibilayers of the enantiomers of the cationic gemini surfactant 1, i.e., (2S,3S)-2,3-dimethoxy-1,4-bis(N-hexadecyl-N,N-dimethylammonium)butane dibromide (la) and (2R,3R)-2,3-dimethoxy-1,4-bis(N-hexadecyl-N,N-dimethylammonium)butane dibromide (1b), have been studied by means of energy dispersive X-ray diffraction. The effect of substrate on the orientation of the sample has been investigated. Dehydration/hydration kinetics of the samples under enviromental conditions has been followed. Furthermore, we have characterized the structural properties of the meso form, (2S,3R)-2,3-dimethoxy-1,4-bis(N-hexadecyl-N,N-dimethylammonium)butane dibromide (1c). The reported results indicate that the spontaneous self-assemblies of the meso form present different physical characteristics

Segregation and phase transition in mixed lipid films

Energy dispersion X-ray diffraction (EDXD) was applied to investigate the structure of partly dehydrated mixed films formed by the phospholipid dimyristoyl phosphatidylcoline (DMPC) and any of the three diastereomers of the dicationic gemini surfactant (2S,3S)-2,3-dimethoxy-1,4-bis(N-hexadecyl-N,N-dimethylammonium) butane dibromide. As the surfactant to lipid molar ratio (R-S/L) increases, the gemini monotonically solubilizes the lipid bilayer promoting the formation of a cubic phase of space group Pm3n segregating from the residual lamellar phase of the lipid. Finally, at R-S/L = 1, the phase transition is complete. The mixed film at the highest surfactant to lipid molar ratio (R-S/L = 2.3) was hydrated by a vapor saturated atmosphere. At full hydration, a cubic to lamellar phase transition occurs. Coarse grain dynamic investigations, carried out as a function of both the surfactant to lipid molar ratio and the number of water molecules for amphiphile unit, allowed us to elucidate the structure of the emerging cubic phase and the hydration-induced structural pathway of the cubic to lamellar phase transition observed by EDXD

The role of the monosialoganglioside-GM1 in the interaction between model membranes and unstructured metastable amyloid oligomers of salmon calcitonin

To investigate the molecular mechanisms of the interaction between amyloid aggregates and model membranes containing GM1, we applied Circular Dichroism (CD) spectroscopy and Transmission Electron Microscopy (TEM). In particular, we studied the interaction of sCT monomers, prefibrillar oligomers (PFOs), proto- and mature-fibers with liposomes made of DPPC, with and without GM1 and cholesterol. All data indicated that the presence of the negatively charged GM1 favored the interaction with all types of aggrega accelerating the formation of beta-structures. TEM data clearly showed that only PFOs were able to modify the bilayer structures by the formation of “amyloid channels” that were clearly visualized. Their structure was very similar to that proposed by Molecular Dynamics simulations for Abeta. CD data are compatible with this hypothesis. We speculate that the electrostatic interaction occurring between positively charged, native, flexible PFOs with the negatively charged GM1 localized in the outer part of the lipid bilayer, drives the initial binding while the hydrophobic interaction could be responsible for the subsequent incorporation in the membrane leading to the formation of the observed amyloid pores

Remote loading of aloe emodin in gemini-based cationic Liposomes

Anthraquinone compound aloe-emodin (AE) has shown antineoplastic, antibacterial, antiviral, and antiinflammatory properties and scavenging activity on free radicals. Because of these therapeutic features, AE has been attracting increasing interest and could be applied in the curing of many diseases. However, until now the physicochemical features of this compound have not been fully investigated; furthermore, its wide application might be hindered by its scarce solubility in aqueous media (∼19 μM). The inclusion of AE in nanocarriers, such as cationic liposomes, could allow its delivery effectively and selectively to target sites, reducing side effects in the remaining tissues. In this work, the weak acid nature of AE, because of its two phenolic functions, was exploited to load it remotely in the internal aqueous phase of liposomes in response to a difference in pH between the inside and outside of the liposomes, pHin > pHout. The inclusion of AE in gemini-based cationic liposomes by the acetate gradient method was obtained at high AE/lipid ratios (up to 1:30)