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Ceramides are essential lipids for skin barrier function, and various classes and species exist in the human stratum corneum (SC). To date, the relationship between skin conditions and ceramide composition in healthy individuals has remained largely unclear. In the present study, we measured six skin condition parameters (capacitance, transepidermal water loss, scaliness, roughness, multilayer exfoliation, and corneocyte cell size) for the SC of the cheeks and upper arms of 26 healthy individuals and performed correlation analyses with their SC ceramide profiles, which we measured via liquid chromatography–tandem mass spectrometry. In the cheeks, high levels and/or ratios of two free ceramide classes containing an extra hydroxyl group in the long-chain moiety and a protein-bound ceramide class containing 6-hydroxysphingosine correlated with healthy skin conditions. In contrast, the ratios of two other free ceramide classes, both containing sphingosine, and a protein-bound ceramide class containing 4,14-sphingadiene correlated with unhealthy skin conditions, as did shortening of the carbon chain of the fatty acid portion of two ceramide classes containing non-hydroxy fatty acids. Thus, our findings help to elucidate the relationship between skin conditions and ceramide composition. [ABSTRACT FROM AUTHOR]

Phosphorus-containing cyclic nitrones, such as DEPMPO, CYPMPO. and DPPMPO. were oxidized by hydrogen letrachloroaurate(III) lo DEPMPOX, CYPMPOX, and DPPMPOX with the precipitation of Au(0). The reaction was depressed by the addition of chloride or hydroxide ions. The peculiar pH dependency was observed in DEPMPOX, CYPMPOX, and DPPMPOX formation, which should be caused by the diethoxyphosphoryl group in DEPMPO, the 1,3-propoxy cyclophosphoryl group in CYPMPO, and the diphenylphosphinoyl group in DPPMPO. The oxidation of the nitrones proceeded through the ligand exchange of [Cl.sup.-] in Au[Cl.sub.4.sup.-] with >[N.sup.+]-[0.sup.-] in nitrone and the nucleophilic addition of the water molecule to the C-2 position in the nitrones, the stepwise infra-molecular transfer of three electrons from the nitrones to Au(III), and the release of the resulting Au(III). The phosphoryl group in the nitrones suppressed the first ligand-exchange interaction by its electronegativity, while the group promoted the electron transfer from the nitrones to Au(III) by its inductive effect. Key words: ESR, spin traps, DMPOX, DEPMPO, CYPMPO, DPPMPO, Au(IlI) ion. Phosphore-contenant les nitrones cycliques, tels que DEPMPO, CYPMPO, et DPPMPO, ont ete oxydes par le tetrachloroaurate(III) d'hydrogene a DEPMPOX, a CYPMPOX, et a DPPMPOX avec la precipitation d'Au(O). La reaction a ete diminuee par l'addition des ions de chlorure ou d'hydroxyde. La dependance particuliere de pH a ete observee dans DEPMPOX, CYPMPOX, et la formation de DPPMPOX, qui devrait etre causee par le groupe de diethoxyphosphoryl dans DEPMPO, le 1,3-propoxy groupe de cyclophosphoryl dans CYPMPO, et le groupe de diphenylphosphinoyl dans DPPMPO. L'oxydation du nitrones a parcoum les etapes l'interaction d'echange de ligand de [Cl.sup.-] dans d'Au[Cl.sub.4.sup.-] avec >[N.sup.+]-[0.sup.-] dans nitrone et I'addition de nucleophilic de la molecule d'eau au C2 position dans le nitrones, le transfer! dans-moleculaire dispose en gradins de trois electrons du nitrones a Au(III), et le relachement du resultant Au(0). Le groupe de phosphoryl dans les nitrones a supprime la premiere interaction d'echange de ligand par son eleclronegativity, alors que le groupe lavorisait le Iransferl d'electron a partir des nitrones a l'Au(III) par son effet induciif. Mots-cles : RPE, piege a spin, DMPOX. DEPMPO, CYPMPO, DPPMPO, ion Au(III)., Introduction Phosphorus-containing nitrone-type spin traps should be useful for the trapping of superoxides. First, a spin trap containing phosphorus atom, 5-diethoxyphosphory 1-5-methyl-1-pyrroline N-oxide (DEPMPO), was developed for superoxide trapping. (1) [...]

When cyclic nitrones, such as 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), 4-phenyl-5,5-dimethyl-1-pyrrolineN-oxide (PDMPO), and 3,3,5,5-tetramethyl-1-pyrroline-N-oxide (M4PO) were mixed with hydrogen tetrachloroaurate(III), DMPOX (5,5-dimethyl-1-pyrrolid-2-one-N-oxyl) type free radicals appeared with the precipitation of Au(0). The reaction did not proceed with noncyclic nitrones, such as N-tert-butyl-[alpha]-phenyl-nitrone (PBN) and [alpha]-(4-pyridyl-1-oxide)-Ntert-butyl-nitrone (POBN). The order of the HAu[Cl.sub.4] decrease was DMPO > PDMPO > M4PO. The reaction was depressed by the addition of chloride or hydroxide ions. 1-Hydroxy-5,5-dimethyl-l-pyrrolid-2-one (HDMPN), the precursor of DMPOX, was also oxidized to DMPOX by HAu[Cl.sub.4]. Every step of the gold reduction from Au(III) to Au(0) can be used for the oxidation of HDMPN to DMPOX. Based on these and previous results, the reaction was assumed to proceed by the following scheme consisting of a ligand exchange interaction of Au[Cl.sub.4.sup.-] with > [N.sup.+] - [O.sup.-] in DMPO, then nucleophilic addition of a water molecule to DMPO, then the stepwise intramolecular transfer of three electrons from DMPO to Au(III), and finally the precipitation of Au(0). Key words: ESR, nitrone, spin traps, DMPO, DMPOX, gold(III) ion. Resume : Lorsque des nitrones cycliques, tels que 5,5-dimethyl-1-pyrroline-N-oxyde (DMPO), 4-phdnyl-5,5-dimethyl-1-pyrroline-N-oxyde (PDMPO), et 3,3.5,5-tetramethyl-1-pyrroline-N-oxyde (M4PO) ont ete me1anges avec du tetrachloroaurate(III) d'hydrogene, des radicaux libres de type DMPOX (5,5-dimethyl-1-pyrrolidine-2-one-N-oxyl) apparut avec la prdcipitation de Au(0). La reaction ne s'est pas produite avec les nitrones non cycliques, tels que N-tert-butyl-[alpha]-phenyl-nitrone (PBN) et [alpha]-(4-pyridyle-1-oxyde)-N-tert-butyl-nitrone (POBN). L'ordre de la diminution de HAu[Cl.sub.4] etait DMPO > PDMPO > M4PO. La reaction a ete abaissee par l'addition d'ions chlorure ou hydroxyde, 1-Hydroxy-5,5dimdthyl-1-pyrrolidine-2-one (HDMPN), le prdcurseur de DMPOX, a ete aussi oxyde en DMPOX par HAu[Cl.sub.4]. Chaque etape de la reduction de For de Au(III) a Au(0) peut etre utilisee pour l'oxydation de HDMPN en DMPOX. Basee sur ceux-ci ainsi que sur les resultats precedents, la reaction a ete expliqude par la combinaison supposee se composant de l'interaction d'echange du ligand de Au[Cl.sub.4.sup.-] avec >[N.sup.+] -[O.sup.-] dans DMPO, de l'addition nucleophilique d'une molecule d'eau a DMPO, du transfert intramoleculaire par etape de trois electrons de DMPO a Au(III), et de la precipitation de Au(0). Mots cles : RPE, nitrone, piege a spin, DMPO, DMPOX, ion Au(III).