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Notizen: Il existe trois méthodes permettant de mesurer l'excrétion sébacée chez l'homme. Ces méthodes ne sont pas équivalentes sur le plan de la précision et de leur utilisation routinière. Une application de la méthode de Schaefer et Kuhn-Bussius est proposée, permettant une détermination rapide et precise des taux des lipides de surface chez l'homme. Une expérimentation, avec cette méthode, chez trente-deux personnes, permet de préciser le mécanisme du prélèvement ainsi que la définition quantitative des types de peau.〈section xml:id="abs1-2"〉〈title type="main"〉SummaryThree main methods to measure quantitatively surface lipids in man have been used. A comparison of the information they produce and their routine practicabilities are given.Adaptation and standardization of the Schaeffer and Kuhn-Bussius method, using a photoelectric absorptiometer and ground glass plates are described.This procedure, applied to thirty-two adults, demonstrated the quantitative nature of the sampling mechanism. A mathematical approach gives the precise definition of the casual-level. This procedure shows that casual-level values appear to be correlated with skin types.

Notizen: Chronobiology governing the hair cycle is a fascinating and complex process. Both the hair growth cycle and the hair shaft growth are coordinated and depend on the interplay of different biological signals and various exogenous stimuli. A latency period may occur between hair shedding (teloptosis, exogen phase) and the early emergence of the next anagen VI stage. This lag time referred to on the hair eclipse phenomenon likely depends on the influence of a series of distinct synchronizers, and does not represent per se a peculiar hair cycle phase. It is the result of some dysregulations of the hair cycling, involving early teloptosis, delayed anagen I initiation or stunted hair growth at any stage between the anagen I and anagen V phases. As such, the hair eclipse phenomenon may be an erratic process occurring in physiopathological conditions affecting hair follicles singly or in focal to generalized patterns. It may be more frequent when it follows synchronized teloptosis occurring in telogen effluvium (newborn alopecia, post-partum alopecia, seasonal alopecia and alopecia areata). It may also be prominent when microinflammation is abutted on the permanent portion of the hair follicle as in dandruff, seborrhoeic dermatitis, androgenic alopecia and photoageing baldness. Local synchronizers such as growth factors and other mediators may eventually be lacking or involved in the hair eclipse phenomenon. Their identification and characterization might drive new corrective or preventive applications.

Notizen: Dandruff is known to be controlled by fungistatic shampoos active against Malassezia spp. These products also remove the loosely attached scales. This study was performed to assess the effect of a 5-min residence time on the efficacy of antidandruff shampoos. Two commercially available shampoos were used in two groups of 21 panelists with severe dandruff. They contained either 1% ketoconazole or 1% piroctone olamine. In each group, intraindividual comparisons were made by a split-scalp design between the effect of a 5-min residence time versus no residence time. Both shampoos induced significant reductions in scaliness and yeast colonization. The beneficial effects were obvious immediately after one single shampooing and 3 days later as well. The improvement was greater with a 5-min residence time. The piroctone olamine treatment benefited more than the ketoconazole treatment from the extension of shampoo-exposure time. In conclusion, the benefit of a residence time in treating dandruff is documented. The level of improvement in efficacy may vary according to the nature of the shampoo.

Notizen: The analysis of the lipids extracted from human hair by silica-gel-column liquid chromatography permitted an isolation of the fraction enriched in free ceramides. These were identified by GC/MS and are related to ceramide classes 2 and 5 in which the long-chain base was predominantly sphinganine. This differs from that observed in the free ceramides found within the stratum corenum.

Notizen: This paper is devoted to a systematic investigation of linear transport properties in strongly coupled binary ionic mixtures of pointlike ions interacting solely through Coulomb interactions. The basic formalism rests upon suitable extensions of the Boltzmann–Ziman equation. Validity conditions for the Lorentzian approximation are thoroughly discussed. High temperature and inelastic contributions to electron transport are emphasized. The formalism is, hereafter, specialized to a thorough investigation of electric, thermal, and mechanical transport coefficients. Basic transport quantities are expressed under a reduced form that allows an easy analytical treatment of temperature and inelastic corrections, parametrized with α=T/TF and (large-closed-square)=β(h-dash-bar)ω, respectively. The former are derived from exact solutions of transport equation through various jellium dielectric functions. Calculation of inelastic contributions is performed through the variational method. Electron transport at T=0 is then thoroughly investigated, including electric and thermal conductivities as well as thermopower and shear viscosity. These results are furthermore extended to an exact calculation of the electric conductivity up to order α2 including properly inelastic contributions, derived in terms of successive moments of the ion–ion structure factors.Results are presented under an analytic and compact form, convenient for a numerical implementation to strongly coupled H+–He2+ mixtures of astrophysical interest. Calculations are performed within binary ionic mixture (BIM) and polarized BIM (PBIM) frameworks, respectively. Ion–ion structure factors are computed through the hypernetted-chain (HNC) scheme, by neglecting bridge diagrams. Most of these results pertain to homogeneous phases. First, the focus is on BIM and a systematic investigation of the Γ-rs and c2 dependence of the transport quantities is performed. Also, attention is paid to the influence of the jellium dielectric function. The T=0 elastic limit is considered first. Next, inelastic and finite temperature corrections are addressed, and BIM to PBIM results are compared. Finally, the electric resistivity behavior is investigated in the vicinity of critical demixing. Discrepancy between BIM and PBIM are thus stressed.

Notizen: Skin surface lipids and lipids from open and closed comedones in acne patients were analysed by thin layer chromatography. The results showed that these lipids were enriched in polar lipids, as compared with the skin surface lipids obtained from controls without acne. In both open and closed comedones, these polar lipids appeared to be derived mainly from the oxidation of squalene, which is in agreement with our previous in vitro results.We suggest that squalene oxidation is the link between comedogenesis and bacterial colonization, and based on this, we propose a hypothesis of the pathogenesis of acne.

Notizen: An in vitro study of the oxidation of squalene, and a description of factors acting on this transformation are presented. Thin layer chromatography was used to quantify the products generated by different oxidation processes. The results clearly show that squalene is a highly effective oxygen-scavenging agent. Its oxidation may first induce comedogenesis and, as a secondary event, cause a large reduction in oxygen tension in the human pilo-sebaceous duct. Porphyrins were confirmed to be highly efficient catalytic factors in the squalene oxidation process. The relationships between comedogenesis, bacterial colonization, and the role of sebum in the pathogenesis of acne are discussed in the light of these findings.

Notizen: Measurement of Sebum Excretion Rate (SER) in patients is a time-consuming test. It is now possible to measure SER 1 h after having degreased the forehead with a 70% ethanol solution. The skin surface lipids (SSL) collected during this time have similar composition to those collected for up to 7 h. A qualitative and quantitative study of sebaceous excretion, on 18 volunteers, from 1 to 7 h after having cleansed the forehead, showed that the refatting kinetics, in all subjects, obeyed the same mathematical law, independent of the subjects' individual SER.

Notizen: A modified photometric technique has shown considerable differences between the refatting kinetics of the scalp and forehead. The refatting on the forehead occurs rapidly, probably due to the large follicular reservoir. The follicular reservoir of the scalp, which bears a large terminal hair, is much smaller and so the refatting time is longer. Thus, sebum excretion and sebum production rates probably correlate better on the scalp than on the forehead, and we suggest that the scalp may be a better site than the forehead for investigating sebaceous gland physiology.

Notizen: Background In the Allergic Rhinitis and its Impact on Asthma (ARIA) classification, intermittent and persistent rhinitis were proposed to replace seasonal and perennial allergic rhinitis (AR).Aim To better understand the ARIA classification of rhinitis.Methods A cross-sectional study was carried out in 591 patients consulting ENT or allergy specialists for AR and 502 control subjects. The diagnosis of AR was based on a score for allergic rhinitis (SFAR) 〈inlineGraphic alt="geqslant R: gt-or-equal, slanted" extraInfo="nonStandardEntity" href="urn:x-wiley:09547894:CEA2274:ges" location="ges.gif"/〉7. Patients were classified according to the four ARIA classes (mild intermittent, mild persistent, moderate/severe intermittent and moderate/severe persistent). Allergen sensitization (skin prick tests (SPTs) or specific IgE) and co-morbidities were examined according to the ARIA classes.Results Ten percent of patients had mild intermittent rhinitis, 14% mild persistent rhinitis, 17% moderate/severe intermittent rhinitis and 59% moderate/severe persistent rhinitis. Most patients with intermittent rhinitis had a pollen sensitivity, but 5% had a single house dust mite (HDM) sensitization. Over 50% of patients with persistent rhinitis were allergic to pollens or HDM. Asthma was present in 24% of rhinitis patients and in only 2% of the control population (P〈0.0001). Patients with moderate/severe persistent rhinitis had the highest asthma prevalence (33%).Discussion Intermittent and persistent rhinitis are not synonymous of seasonal and perennial rhinitis. Most patients consulting specialists have severe rhinitis. Asthma prevalence increases with duration and severity of rhinitis supporting the ARIA major recommendation that patients with persistent rhinitis should be evaluated for asthma.