Phase separation in ceramide[NP] containing lipid model membranes: neutron diffraction and solid-state NMR.

The stratum corneum is the outermost layer of the skin and protects the organism against external influences as well as water loss. It consists of corneocytes embedded in a mixture of ceramides, fatty acids, and cholesterol in a molar ratio of roughly 1 : 1 : 1. The unique structural and compositional arrangement of these stratum corneum lipids is responsible for the skin barrier properties.

Synthesis of specifically deuterated ceramide [AP]-C18 and its biophysical characterization using neutron diffraction.

The very heterogeneous group of ceramides is known to be mandatory for proper barrier functions of the outermost layer of mammalian skin, referred to as stratum corneum (SC). The synthesis of a specifically deuterated ceramide [AP]-C18 variant is described. The synthesized ceramide contains the racemic forms of the α hydroxy fatty acid.

Influence of the penetration enhancer isopropyl myristate on stratum corneum lipid model membranes revealed by neutron diffraction and H NMR experiments.

The stratum corneum (SC) provides the main barrier properties in native skin. The barrier function is attributed to the intercellular lipids, forming continuous multilamellar membranes. In this study, SC lipid membranes in model ratios were enriched with deuterated lipids in order to investigate structural and dynamical properties by neutron diffraction and H solid-state NMR spectroscopy.

Localization of methyl-branched ceramide [EOS] species within the long-periodicity phase in stratum corneum lipid model membranes: A neutron diffraction study.

The outermost layer of the mammalian skin, the stratum corneum (SC), is a very thin structure and realizes simultaneously the main barrier properties. The penetration barrier for xenobiotica is mostly represented by a complex lipid matrix. There is great interest in the subject of getting information about the arrangement of the lipids, which are mainly ceramides (CER), free fatty acids (FFA) and cholesterol (CHOL).

Preparation of a New Oligolamellar Stratum Corneum Lipid Model.

In this study, we present a preparation method for a new stratum corneum (SC) model system, which is closer to natural SC than the commonly used multilayer models. The complex setup of the native SC lipid matrix was mimicked by a ternary lipid mixture of ceramide [AP], cholesterol, and stearic acid. A spin coating procedure was applied to realize oligo-layered samples.

Depletion of the AMPAR reserve pool impairs synaptic plasticity in a model of hepatic encephalopathy.

Hepatic encephalopathy (HE) is the most common neuropsychiatric complication of acute or chronic liver failure. Clinical symptoms include cognitive and intellectual dysfunction as well as impaired motor activity and coordination. There is general consensus that increased levels of ammonia play a central role in the pathogenesis of HE.

Synaptic plasticity in hepatic encephalopathy - a molecular perspective.

Hepatic encephalopathy (HE)(1) is a common neuropsychiatric complication of both acute and chronic liver disease. Clinical symptoms may include motor disturbances and cognitive dysfunction. Available animal models of HE mimic the deficits in cognitive performance including the impaired ability to learn and memorize information.

Lipophilic penetration enhancers and their impact to the bilayer structure of stratum corneum lipid model membranes: neutron diffraction studies based on the example oleic acid.

The present study analyzes the effect of the lipophilic penetration enhancer oleic acid on the bilayer structure of stratum corneum (SC) lipid model membranes based on Ceramide AP by using the neutron diffraction technique. Our results indicate the formation of a single lamellar phase in the presence of oleic acid under the chosen experimental conditions; a separated fluid-like oleic acid-rich phase was not detected in the present study. By comparing the internal membrane structure received from Fourier synthesis with the model system lacking oleic acid, considerable structural changes in terms of impairment of the lamellar order were found after incorporation of the penetration enhancer into the bilayers.

Alternative splicing of the cardiac sodium channel creates multiple variants of mutant T1620K channels.

Alternative splicing creates several Na(v)1.5 transcripts in the mammalian myocardium and in various other tissues including brain, dorsal root ganglia, breast cancer cells as well as neuronal stem cell lines. In total nine Na(v)1.

New nanosized technologies for dermal and transdermal drug delivery. A review.

Nanocarriers are promising dermal and transdermal drug delivery systems. The review recapitulates the most prominent nanocarriers such as microemulsions, liposomes and micro- and nanoparticles for the dermal and transdermal application. Microemulsions have a high solubilization capacity even for poorly soluble drugs and combined with their permeation enhancing effect high flux rates can be obtained.

Structure and function of splice variants of the cardiac voltage-gated sodium channel Na(v)1.5.

Voltage-gated sodium channels mediate the rapid upstroke of the action potential in excitable tissues. The tetrodotoxin (TTX) resistant isoform Na(v)1.5, encoded by the SCN5A gene, is the predominant isoform in the heart.

Evidence of free fatty acid interdigitation in stratum corneum model membranes based on ceramide [AP] by deuterium labelling.

This research paper provides direct evidence concerning the localisation of free fatty acids in stratum corneum lipid model membranes. We employed partially deuterated free fatty acids to gain further information about the assembly of a stratum corneum lipid model membrane based on a ceramide of the phytosphingosine-type (ceramide [AP]) with particular respect to the position of the deuterated groups of the free fatty acids. The application of behenic-22,22,22-d(3)-acid and cerotic-12,12,13,13-d(4)-acid confirmed that the short-chain ceramide [AP] forces the longer-chained free fatty acids to incorporate into the bilayer created by ceramide [AP].