RESUMO
This article summarizes the current knowledge of the composition, self-assembly, and molecular organization of the stratum corneum (SC) lipids, reviews the evidence connecting these parameters and the barrier properties of human skin, and outlines the immediate issues in the field of SC lipid research.
Assuntos
Epiderme/química , Matriz Extracelular/química , Lipídeos/química , Epiderme/ultraestrutura , Matriz Extracelular/ultraestrutura , Humanos , Microscopia Eletrônica , Permeabilidade , Perda Insensível de Água , Difração de Raios XRESUMO
A new simple concept for a miniaturized monolayer trough is described. The overall monolayer area in the expanded state is approximately 150 mm2 and can be reduced by a factor of 2. The surface area is a function of the shape of the meniscus formed by the subphase and is controlled by the amount of water in the monolayer trough. The controlled compression of monolayers to a desired area per molecule with simultaneous observation of the lateral distribution of fluorescently labeled molecules is shown. A biological reaction between a specific antibody and lipid anchored peptide demonstrates the feasibility of monolayer experiments, which require only very small quantities of substance (in the pmol range). This trough might also be a valuable tool for the 2D crystallization of proteins at lipid layers via specific binding sites such as metal chelators.
Assuntos
Lipídeos de Membrana/química , 1,2-Dipalmitoilfosfatidilcolina/química , 4-Cloro-7-nitrobenzofurazano/química , Capsídeo/química , Proteínas do Capsídeo , Lipoproteínas/química , Microscopia de Fluorescência , Politetrafluoretileno/química , Propriedades de Superfície , Proteínas Virais/químicaRESUMO
The first morning urine in 206 women with pregnancy or no pregnancy was examine for and increase of chorionic gonadotropic hormone by means of three tests: Sevatest HCG latex, Gravimmun 2 (imported by first direction) and Gravindex HCG (imported by second direction). Diagnostic reliability of the tests was studied in women to establish early pregnancy. It was fond that the tests, imported by the first direction, could successfully substitute those, imported by the second direction, in the routine diagnostic practice.
Assuntos
Testes Imunológicos de Gravidez/instrumentação , Adolescente , Adulto , Gonadotropina Coriônica/urina , Estudos de Avaliação como Assunto , Feminino , Humanos , Gravidez , Kit de Reagentes para Diagnóstico , Fatores de TempoRESUMO
The molecular self-organization and structural properties of peptide assemblies at different interfaces, using either amphipathic or hydrophobic polypeptide helices, is described. The two peptides under investigation form stable monolayers on the water surface under the conservation of their molecular conformation, as studied by circular dichroism and polarization-modulation Fourier transform infrared (FTIR) spectroscopy. Using surface plasmon resonance and reflection-absorption FTIR, we show that such molecular layers can be transferred unaltered to solid substrates. Most importantly, the molecular orientation of the hydrophobic helices on solid supports such as gold can be controlled by choosing a particular procedure for the layer formation. The helices were oriented parallel to the interface in Langmuir-Blodgett monolayers, and perpendicular to the interface in self-assembled monolayers. Our reflection-absorption FTIR measurements have delivered for the first time direct experimental evidence for the molecular conformation and orientation of pure peptide monolayers. Suitable reference spectra of polypeptides with defined conformation and orientation are necessary to use this technique for the determination of the molecular orientation of peptides in monomolecular films. We have solved the problem for alpha-helical polypeptides by using bacteriorhodopsin as a reference in combination with synthetic alpha-helices of defined interfacial orientation. The present study shows the possibility of constructing immobilized peptide monolayers with predefined macroscopic properties and molecular structure by choosing the proper polypeptide amino acid sequence, the technique used for layer formation, and the supporting surface properties.