Search

Carriers of loss-of-function mutations in the filaggrin gene (LoF FLG) have less natural moisturizing factor (NMF) in their stratum corneum (SC) and an increased risk of atopic dermatitis (AD). Natural moisturizing factor can be measured noninvasively by Raman spectroscopy. The use of Raman-derived NMF at birth to screen for FLG genotype could inform targeted AD prevention, but values in neonatal populations are largely unexplored.

We demonstrate the feasibility of short wave infrared (SWIR) spectroscopy combined with tape stripping for depth profiling of lipids and water in the stratum corneum of human skin. The proposed spectroscopic technique relies on differential detection at three wavelengths of 1720, 1750, and 1770 nm, with varying ratio of the lipid-to-water absorption coefficient and an ‘isosbestic point’. Comparison of the data acquired using SWIR spectroscopy with that obtained by a gold standard for non-invasive quantitative molecular-specific skin measurements, namely confocal Raman spectroscopy (CRS), revealed specificity of the proposed modality for water and lipid quantification. At the same time, we provide evidence showing aberrant sensitivity of Corneometer hydration read-outs to the presence of skin surface lipids, and a lack of sensitivity of the Sebumeter when attempting to measure the lipids of the cornified lipid envelope and intracellular lipid layers. We conclude that a spectroscopic SWIR-based spectroscopic method combined with tape stripping has the potential for depth profiling of the stratum corneum water and lipids, due to superior measurement sensitivity and specificity compared to the Corneometer and Sebumeter.

A facile method for quantifying the concentration of the powerful and widely available hallucinogen salvinorin A (a selective kappa opioid agonist) from non-human primate cerebrospinal fluid (CSF) and human plasma has been developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in positive electrospray ionization (ESI) mode. With CSF solid phase extraction can be avoided completely by simply diluting each sample to 10% (v/v) acetonitrile, 1% (v/v) formic acid and injecting under high aqueous conditions for analyte focusing. Extensive plasma sample preparation was investigated including protein precipitation, SPE column selection, and plasma particulate removal. Human plasma samples were centrifuged at 21 000 × gfor 4 minutes to obtain clear particulate-free plasma, from which 300 μL was spiked with internal standard and loaded onto a C18SPE column with a 100 mg mL−1loading capacity. Guard columns (C18, hand packed 1 mm × 20 mm) were exchanged after backpressure increased above 4600 psi, about 250 injections. A shallow acetonitrile/water gradient was used, 29–33% CH3CN over 8 minutes to elute salvinorin A. Reduction of chemical noise was achieved using tandem mass spectrometry with multiple reaction monitoring while sensitivity increases were observed using a 50 μL injection volume onto a small bore analytical column (C18, 1 mm ID × 50 mm) thus increasing peak concentration. Limits of quantification were found to be 0.0125 ng mL−1(CSF) and 0.05 ng mL−1(plasma) with interday precision and accuracy below 1.7% and 9.42% (CSF) and 3.47% and 12.37% (plasma) respectively. This method was used to determine the concentration of salvinorin A from an in vivoRhesus monkey study and a trial of healthy human research participants, using behaviorally active doses.

A hallmark of atopic eczema (AE) is skin barrier dysfunction. Lipids in the stratum corneum (SC), primarily ceramides, fatty acids, and cholesterol, are crucial for the barrier function, but their role in relation to AE is indistinct. Filaggrin is an epithelial barrier protein with a central role in the pathogenesis of AE. Nevertheless, the precise causes of AE-associated barrier dysfunction are largely unknown. In this study, a comprehensive analysis of ceramide composition and lipid organization in nonlesional SC of AE patients and control subjects was performed by means of mass spectrometry, infrared spectroscopy, and X-ray diffraction. In addition, the skin barrier and clinical state of the disease were examined. The level of ceramides with an extreme short chain length is drastically increased in SC of AE patients, which leads to an aberrant lipid organization and a decreased skin barrier function. Changes in SC lipid properties correlate with disease severity but are independent of filaggrin mutations. We demonstrate for the first time that changes in ceramide chain length and lipid organization are directly correlated with the skin barrier defects in nonlesional skin of AE patients. We envisage that these insights will provide a new therapeutic entry in therapy and prevention of AE.

As part of our continuing efforts toward more fully understanding the structure−activity relationships of the neoclerodane diterpene salvinorin A, we report the synthesis and biological characterization of unique cycloadducts through [4+2] Diels−Alder cycloaddition. Microwave-assisted methods were developed and successfully employed, aiding in functionalizing the chemically sensitive salvinorin A scaffold. This demonstrates the first reported results for both cycloaddition of the furan ring and functionalization via microwave-assisted methodology of the salvinorin A skeleton. The cycloadducts yielded herein introduce electron-withdrawing substituents and bulky aromatic groups into the C-12 position. Kappa opioid (KOP) receptor space was explored through aromatization of the bent oxanorbornadiene system possessed by the cycloadducts to a planar phenyl ring system. Although dimethyl- and diethylcarboxylate analogues 5and 6retain some affinity and selectivity for KOP receptors and are full agonists, their aromatized counterparts 13and 14have reduced affinity for KOP receptors. The methods developed herein signify a novel approach toward rapidly probing the structure−activity relationships of furan-containing natural products.

The application of in vivo Raman spectroscopy for clinical diagnosis demands dedicated software that can perform the necessary signal processing and subsequent (multivariate) data analysis, enabling clinically relevant parameters to be extracted and made available in real time. Here we describe the design and implementation of a software package that allows for real-time signal processing and data analysis of Raman spectra. The design is based on automatic data exchange between Grams, a spectroscopic data acquisition and analysis program, and Matlab, a program designed for array-based calculations. The data analysis software has a modular design providing great flexibility in developing custom data analysis routines for different applications. The implementation is illustrated by a computationally demanding application for the classification of skin spectra using principal component analysis and linear discriminant analysis. Copyright © 2002 John Wiley & Sons, Ltd.

An automated confocal Raman microspectrometer for rapid measurement of molecular concentration profiles in the skin is described. It permits the successive collection of Raman spectra at a range of depths below the skin surface. The axial resolution of the confocal Raman microspectrometer is 5.1±0.2 µm. The setup was applied to determine water concentration profiles of the stratum corneum and to determine changes therein as a result of hydration of the skin. Copyright © 2000 John Wiley & Sons, Ltd.

The hoatzin (Opisthocomus hoazin) lives in the humid lowlands of northern and central South America, often in riparian habitats. It is a slender bird approximately 65 cm in length, brownish with lighter streaks and buffy tips to the long tail feathers. The small head has a ragged, bristly crest of reddish-brown feathers, and the bare skin of the face is bright blue. It resembles a chachalaca (Ortalis, Cracidae) in size and shape, but its plumage and markings are similar to those of the smaller guira cuckoo (Guira guira). The hoatzin (pronounced Watson) has been a taxonomic puzzle since it was described in 1776. It usually has been viewed as related to the gallinaceous birds, but alliances to other groups have been suggested, including the cuckoos. We present DNA sequence evidence from the 12S and 16S rRNA mitochondrial genes, and from the nuclear gene that codes for the eye lens protein, alpha A-crystallin. The results indicate that the hoatzin is most closely related to the typical cuckoos and that the divergence occurred at or near the base of the cuculiform phylogenetic tree.

Noninvasive techniques that provide detailed information about molecular composition, structure, and interactions are crucial to further our understanding of the relation between skin disease and biochemical changes in the skin, as well as for the development of penetration enhancers for transdermal drug administration. In this study we present in vitro and in vivo Raman spectra of human skin. Using a Raman microspectrometer, in vitro spectra were obtained of thin cross sections of human skin. They provided insight into the molecular composition of different skin layers. Evidence was found for the existence of a large variation in lipid content of the stratum corneum. A simple experimental setup for in vivo confocal Raman microspectroscopy of the skin was developed. In vivo Raman spectra of the stratum corneum were obtained at different positions of the arm and hand of three volunteers. They provided evidence for differences in the concentration of natural moisturizing factor at these positions. © 1998 John Wiley & Sons, Inc. Biospectroscopy 4: S31–S39, 1998