bluuebunny/crossref_metadata_2025_split huggingface dataset:
Skin colour typology and suntanning pathways
Authors: CHARDON A. , CRETOIS I. , HOURSEAU C. 
Published: May 2007

SynopsisThe evaluation of sun‐product efficacy, with laboratory solar simulators or in actual sun, implicates clinical and subjective assessment of the various skin responses in terms of wavelengths constitutive of solar light. These photobiological responses vary according to skin types and particularly to basic skin melanic content, i.e. with skin colour. Now, the instrumental measurement of live skin colour has become easier to perform, fast and reliable. Based on the standard CIE‐L*a*b* colour system and correlated with the human eye, this technique was used to define the skin colour domain of the caucasian population, to propose a skin colour classification, and then to objectively follow, over a three week period, the dynamics and kinetics of tanning induced by UVB, UVA and UVB ± A multi‐exposures on the three skin categories. The specific directions in the three‐dimensional L*a*b* colour space of the tanning components, i.e. erythema, immediate pigmentation and constitutional melanization, as well as the resulting tanning pathways, were analysed and defined in the three‐dimensional colour space, using a vectorial method. The UVB, UVA and UVB ± A tannings were differentiated by their intensity, their hue and especially their lasting capacity: UVA tanning clearly appeared more lasting than UVB. In addition, the UVA*UVB interaction on tanning intensity was not found to be significant. With the skin colour classification and the tanning models, this comprehensive study supplies a basic tool for the colorimetric interpretation of the skin phenomena involved, provided that this interpretation is always considered in the three dimensions of the colour space. It also suggests some useful practical applications for sun product formulation and evaluation.
The role of primary alkanolamines in cosmetic formulation
Authors: BREMECKER K.‐D. , NATONSKI J.L. , EACHUS A.C. 
Published: May 2007

SynopsisAlkaline products are commonly used in cosmetic preparations as neutralizing agents for acid‐functional raw materials. Primary alkanolamines can provide positive attributes in such cases. The properties of nitroparaffin‐derived primary alkanolamines are compared here with the general requirements for cosmetic‐type acid‐neutralizing materials.Acid‐functional copolymers, used as hair fixatives in both aerosol and non‐aerosol products, are efficiently solubilized by neutralization with 2‐amino‐2‐methyl‐1‐propanol (amino‐methylpropanol) in a variety of aqueous and non‐aqueous systems. The effects of such neutralization on resultant film properties which influence product performance are discussed in detail.Upon neutralization, crosslinked acrylic‐acid polymers of varying molecular weights (carbomers) provide significant benefits when used as thickeners, gellants or emulsifiers in cosmetic products. New data are added to previous knowledge on the use of tris(hydroxymethyl)aminomethane (tromethamine) as a neutralizing agent for three resins, especially in gelled formulations. Alcohol compatibility, pH behaviour, and viscosity characteristics of such formulations are described. In addition, toxicological considerations of primary alkanolamines are addressed.Further to the above applications, nitroparaffin‐derived primary alkanolamines can be effectively used as cosmetic emulsifiers (in the form of their fatty‐acid soaps), dispersants or co‐dispersants for particulate‐containing products, and pH buffers/stabilizers.
The determination of the antiperspirant activity of aluminium‐chlorhydrate by digital image‐analysis
Authors: SAUERMANN G. , HOPPE U. , KLIGMAN A.M. 
Published: May 2007

SynopsisThe method of Minor to visualize by iodine–starch–reaction the activity of sweat glands was used in combination with image‐analysis to quantify sweat‐secretion. Aqueous aluminium chlorohydrate solutions (ACH) (1, 2, 4, 8, 16%) were applied twice daily for 6 days to defined areas of the lower volar forearms. After 3 and 6 days of treatment perspiration was induced by thermal stress. The dark blue spots on top of active glands which are formed by iodine–starch–complexes were counted and their projection area was measured by an image analysing system. Increasing concentrations of ACH lower the number of active sweat glands, while the size of the dark spots is not dependent on the concentration of the active ingredient.
Non‐saponifiable fraction of cocoa shell butter: effect on rat and human skin fibroblasts
Authors: WAROCQUIER‐CLEROUT R. , SIGOT M. , OURAGHI M. , CHAVERON H. 
Published: May 2007

SynopsisNon‐saponifiable lipid fraction (ICSB) extracted from cocoa shell butter was solubilized in dimethylformamide (DMF) and analysed for its biological activity on growth of rat and human fibroblasts. Non‐saponifiables (10 μg ml−1) partially protected cells from toxicity of DMF (1%) and allowed the growth of fibroblasts cultivated in optimal conditions (10% fetal calf serum‐FCS, 37°C) or improved the survival of cells maintained in altered conditions (2.5% FCS, 35°C). At higher concentration (ICSB 50 μg ml−1, DMF 1%), the protective effect was suppressed. ICSB was fractionated by chromatography into four compounds: sterols, terpenic alcohols, tocopherols and hydrocarbons ± carotenoids. We found that biological activity of ICSB was mostly due to the major fraction containing sterols.
Les enzymes de l'espace extra‐cellulaire du stratum corneum
Authors: FORESTIER J.P. 
Published: May 2007

SynopsisBien que le stratum corneum soit composé de cellules ‘mortes’, il est le siège d'une activité métabolique très importante. Mais, contrairement à la plupart d'autres tissus, cette activité a la particularité d'étre extra‐cellulaire. Elle est due à des enzymes excrétées par les Corps d'Odland avec les bicouches céramidiques.Ces enzymes sont des hydrolases, elles sont identiques ou très proches de celles des lysosomes. Les principales activités observées correspondent à une (ou des) glycosidase(s), une phospholipase, une sphingomyélinase, une phosphatase, une (ou des) estérase(s), des sulfatases, des protéases. Comme les hydrolases des lysosomes, elles semblent peu spécifiques.Ce pool enzymatique pourrait jouer plusieurs rôles fondamentaux, notamment:1. La transformation des bicouches gluco‐céramidiques en bicouches ceramidiques plus lipophiles;2. L'élimination de la membrane plasmique, dont certains produits du catabolisme, comme les acides gras et les céramides, peuvent être intégrés aux bicouches céramidiques;3. La diminution de la cohésion entre les cornéocytes;4. La protection contre l'intrusion de corps étrangers.Comme tout système enzymatique, les hydrolases extra‐cellulaires, sont certainement soumises à des régulations. Plusieurs de ces régulations sont envisagées.A partir de considérations d'enzymologie, le pH de la base du stratum corneum peut être estiméà environ 5.En cosmétologie, les enzymes du stratum corneum sont mises à contribution pour rendre actifs des précurseurs.L'étude des conséquences des modifications de l'activité enzymatique sur l'état de la peau pourrait constituer une future voie de recherche extrêmement prometteuse.
Physico—chemical modifications of liposome structures through interaction with surfactantsy‡
Authors: RIBOSA I. , GARCIA M.T. , PARRA J.L. , de la MAZA A. , SANCHEZ‐LEAL J. , TRULLAS C. , TSI A. , BALAGUER F. , PELEJERO C. 
Published: May 2007

SynopsisThe liposome‐surfactant interaction has been studied in this paper through the disrupting effect caused by surfactant molecules on large unilamellar vesicles prepared by reverse‐phase evaporation. This process leads, in the end, to the rupture of such structures and to the solubilization of the phospholipidic components, via mixed surfactant‐phospholipid micelle formation. This phenomenon is described by a three‐stage model and characterized by two parameters: the highest surfactant/phospholipid ratio that can exist in a vesicle (Re sat) and the lowest surfactant/phospholipid ratio required to keep the lipid and surfactant in the form of mixed micelles (Re sat). These parameters have been determined by spectrophotometry and 31P NMR spectroscopy, obtaining results in a good agreement with both techniques. The surfactants tested have been: sodium dodecyl sulfate (SDS), sodium laurylether sulfate (SLES), N‐hexadecyl‐trimethylammonium bromide (HTAB), octylphenol series (8–20 EO) and alkylbetaines(C‐10, C‐12 and C‐14). Different Re sat and Re sol values have been obtained for each of the surfactants. This has permitted a study of the solubilizing capacity versus the phospholipidic bilayer of the different surfactants as a function of their structure.
Comparison of percutaneous penetration in vitro using clofibric acid esters and amides as novel enhancers in two species: mouse and guinea pig
Authors: MICHNIAK B.B. , CHAPMAN J.M. 
Published: May 2007

SynopsisA series of clofibric acid esters and amides has been assessed as dermal penetration enhancers towards hydrocortisone‐21‐acetate, a model drug. In vitro percutaneous absorption experiments on three skin sources (athymic nude mouse, hairless mouse, and hairless guinea pig) showed several compounds to be effective penetration enhancers, the octyl amide providing an approximately 20‐fold increase in 24 h diffusion cell receptor drug concentration and 5.7 fold in total steroid skin retention in nude mouse. Azone produced significantly higher (p <0.05) permeation rates than the octyl amide enhancer, but there was a smaller increase in 24 h receptor concentrations, and Azone steroid skin concentrations were significantly less (p < 0.05) than those for the amide. There was no significant difference (p < 0.05) between enhancement in hairless and athymic nude mouse, however, hairless guinea pig skin showed decreased enhancer effectiveness.
New gelification method for vegetable oils I: cosmetic application
Authors: AIACHE J.‐M. , GAUTHIER P. , AIACHE S. 
Published: May 2007

SynopsisA new gelification process of vegetable oils was developed using a cellulose derivative in order to obtain transparent oleogels (anhydrous gels based on fatty components) of different consistencies. The study of their structure has been carried out by infra‐red spectroscopy, differential thermal analysis and X‐ray diffractometry. All these physical tests have demonstrated the gel structure of the formulations. Finally, a rheological study was run to elucidate their specific properties and their stability during storage.
Studies on the stability of selected viruses in cosmetics
Authors: von RHEINBABEN F. , HEINZEL M. 
Published: May 2007

SynopsisInformation concerning the risks emerging from the use of cosmetics contaminated with viruses is rarely reported. Therefore, we investigated the stability of viruses within different types of cosmetics. Test products were artificially contaminated with different viruses, which, due to the application of the products, have hygienic relevance. Virus persistence was observed by determining the reisolation rate. With this knowledge we were able to estimate the initial contamination of finished products and raw materials.Viruses with hygienic relevance could neither be detected in finished products nor in raw materials. We can conclude from this that cosmetics seem to be safe with regard to initial contamination. However, our results clearly showed that secondary contamination with viruses can have a persistence which is high enough to pose a hygienic risk through cross contamination.
In vitro cultured human skin cells as alternatives to animals for skin irritancy screening
Authors: PONEC MARIA 
Published: May 2007

SynopsisIn the last few years a lot of attention has been paid to the development of the in vitro models which would substitute for animals in cutaneous irritancy studies. These models explore either organ or explant cultures using freshly excised skin or serial cultures of isolated skin cells (epidermal keratinocytes or dermal fibroblasts). The organ or explant models are suitable only for short exposures of skin samples to the compounds tested and the use of it will always be restricted by the limited availability of fresh human skin. The model that uses submerged cultures of keratinocytes or fibroblasts permits the production of a large number of cells, and permits large scale toxicity screening tests with many substances, that can be applied in a broad concentration range. Since the stratum corneum is absent in conventional (submerged) keratinocyte culture systems, this model is mainly suited for testing of water soluble compounds and it is less suitable for poorly soluble compounds and for topical products consisting of complex formulations which are made of active ingredients and their vehicles. This shortcoming can be overcome by using ‘organotypic cultures’in which keratinocytes are grown at the air‐liquid interface on a suitable dermal substrate. Under these conditions, the culture forms a multilayered epidermis showing an overall structure which resembles that of a native epidermis. The presence of a coherent stratum corneum layer in these cultures permits the application of potential irritants at concentrations and in formulations as applied in vivo. For the evaluation of toxicity a number of tests have already been developed: assessment of cell viability, changes in cell morphology, modulation of cell proliferation and differentiation, monitoring of membrane damage, the measurements of the uptake or incorporation of radioactive precursors, establishment of the modulation of cell metabolism, determination of the release of inflammatory mediators, etc. All these in vitro techniques are still in a state of validation as far as their predictive value for in vivo skin irritancy is concerned.
Prediction of the percutaneous penetration of ultra‐violet filters used in sunscreen formulations
Authors: WATKINSON A.C. , BRAIN K.R. , WALTERS K.A. , HADGRAFT J. 
Published: May 2007

SynopsisThe application of a mathematical model to estimate the extent of transdermal absorption of UV‐filters commonly used in sunscreen formulations is described. Percutaneous penetration is not a factor that has been properly addressed in the literature and the penetration/time profiles generated here suggest that significant amounts of certain of these compounds may penetrate the skin and enter the systemic circulation. The results presented indicate that further research in this area is necessary and the authors suggest that in vitro experiments with human skin are conducted with both current and new UV filters to quantify the degree of dermal penetration of these substances.
In‐use tolerability of two new syndet bars with sodium cocoyl isethionate, disodium lauryl sulfosuccinate and wheat starch as major ingredients in differing relations: results of a cross‐over trial
Authors: KORTING H.C. , LUKACS A. , HAMM D. , STANZL K. , BRAUN‐FALCO O. 
Published: May 2007

SynopsisIn a cross‐over trial two different new syndet bars differing in their content of sodium cocoyl isethionate, disodium lauryl sulfosuccinate and wheat starch as major components were compared in the cleansing of hand skin of 72 healthy volunteers. The preparation designated ‘T’containing a higher amount of wheat starch turned out to be less irritant as judged from the parameters itching and erythema (p < 0.05, Wilcoxon's test for matched pairs). The present trial design looks appropriate to differentiate the irritancy potential of two chemically similar syndet bar preparations.
Influence of different oils on penetration of human hair by fungi
Authors: BAHUGUNA S. , KUSHWAHA R.K.S. 
Published: May 2007

SynopsisThe hair perforating ability of Microsporum gypseum and Trichophyton vanbreuseghemii was tested in presence of seventeen oils. Clove, olive and turpentine oils were found to be fully inhibitory for hair penetration by both fungi. Hair segments smeared with cantheridine oil and keocarpin hair vitalizer failed to reveal any perforation by T. vanbreuseghemii whereas arnica and shikakai oils showed little perforation by this fungus.
A simple and specific high performance liquid chromatography method for the assay of a series of novel dermal penetration enhancers
Authors: MICHNIAK B. B. , SEYDA K. L. 
Published: May 2007

SynopsisA series of clofibric acid amides has been synthesized and previously reported by the authors as possessing enhancer activity in vitro in athymic nude mouse skin against model drugs, hydrocortisone‐21‐acetate and β‐methasone‐17‐valerate. An assay was required for each of these enhancers however, which would be specific for each compound and would also separate model drugs and their metabolite peaks. This study reports reverse phase high performance liquid chromatography assays for clofibric acid amide and seven derivatives (Ia–Ig). All enhancers showed maximum absorption at 232 nm, betamethasone (BM) and its valerate (BMV) at 238 nm, and hydrocortisone (HC) and its acetate (HCA) at 242 nm. Practical units of detection for the amides were 0.46–2.8 μg ml‐1 and peaks were sharp and well‐separated from steroid peaks in three vehicles – methanol alone. Franz diffusion cell receptor phase samples (isotonic phosphate buffer), and full‐thickness athymic nude mouse skin extracts in methanol.Mobile phases consisted of various proportions of acetonitrile and water, some with 2‐propanol. The octyl amide for example, with mobile phase CH3CN: H2O (85:15) at 1 ml min‐1 had a retention time (tR) of 7.9 mins. Under the same conditions, retention times for the steroids were HC, tR= 3.3 mins; HCA, tR= 4.3 mins; BM, tR= 3.4 mins; BMV, tR= 4.6 mins.
A cell suspension agar diffusion test using Neutral Red release to assess the relative irritancy potential of cosmetic ingredients and formulations
Authors: BUTLER N.J. , LANGLEY G.R. , WINWOOD J. 
Published: May 2007

SynopsisAn established cytotoxicity test for plastic materials in medical devices has been adapted and used to assess the relative potential irritancy of cosmetic ingredients and formulations during product development. Serum‐free medium containing a novel protein supplement supported growth in suspension of LS mouse fibroblast cells. Release of the vital dye Neutral Red from pre‐loaded cells suspended in agar was the endpoint. Test substances and reference standards were applied to a central well cut into the agar, a sensitive method which allowed accurate dose application and yielded consistent results. Relative irritancy potential was measured quantitatively by comparing the diameters of the clear zones of damaged cells which surround the central well. The test has been used with raw materials such as surfactants, preservatives and herbal extracts, as well as finished products ranging from shampoos and conditioners to creams, lotions and coloured cosmetics. The method is practical, versatile, reproducible and economic to use.
UV filters for hair protection
Authors: BERNHARDT P. , GIESEN M. , HOLLENBERG D. , HUBBUCH M. , KALHÖFER V. , MAIER H.E. , MARTIN V. , MÜNZING H.‐P. , OELSCHLÄGER T. , SCHWAN A. , SPERLING K. , TENNIGKEIT J. 
Published: May 2007

SynopsisHair damage, caused by sunlight, and the possibility to protect hair against sunlight by means of cosmetic formulations was studied. For this, five UV‐filters were tested: benzophenone‐3 (UV‐A/UV‐B); benzophenone‐4 (UV‐A/UV‐B); phenylbenzimidazole sulfonic acid (UV‐B); butylmethoxydibenzoylmethane (UV‐A); octyl dimethyl PABA (UV‐B). The stability of the UV‐filters was tested as pure substances as well as in two cosmetic formulations: a setting lotion and a shine spray. The degree of decolouration and stress strain behaviour were determined. The benzophenones had the best protection ability both on colour and on morphology. Stability data and UV‐spectra are discussed.
Skin mechanics measured in vivo using torsion: a new and accurate model more sensitive to age, sex and moisturizing treatment
Authors: SALTER D.C. , McARTHUR H.C. , CROSSE J.E. , DICKENS A.D. 
Published: May 2007

SummaryMeasurements of skin mechanics are required to understand better cracking and flaking of the epidermis and loss of ‘elasticity’with age in the dermis. Improvements in torsional testing are described here. The resulting data was fitted to algebraic models, the parameters of which can serve both as a concise description of the responses and as a means of relating them to skin structure and physiology. This investigation looks into the suitability of seven such algebraic models. Five of the models examined here appear to be new.Using the commercially available Dia‐Stron DTM Torque Meter with our own software, model parameters were studied as indicators of the effects of age and sex in 41 people, and of skin moisturizing treatments in a further 10 people. The two models in the literature were both found to be substantially less accurate and sensitive representations of experimental data than one of the new models proposed here based on the Weibull distribution. This ‘WB model’was consistently the one best able to distinguish differences and detect changes which were statistically significant. The WB model appears to be the most powerful and efficient available. Use of this model makes it possible to demonstrate in vivo a statistically significant mechanical difference between male and pre‐menopausal female skin using only one parameter (p= 0.0163, with 18 males and 19 females) and to demonstrate a statistically significant mechanical difference between successive decades of age in female skin using only one parameter (p= 0.0124, n= 24). The two parameters of the model most sensitive to skin structure, function and treatment have been combined to form the axes of a ‘Skin condition chart’. Any person can be located on this chart at a point indicating their overall skin condition in mechanical terms and any changes in that condition can be clearly demonstrated by movement across the plot.
Moisturization processes in living human skin studied by magnetic resonance imaging microscopy
Authors: SALTER D.C. , HODGSON R.J. , HALL L.D. , CARPENTER T.A. , ABLETT S. 
Published: May 2007

SummaryMagnetic resonance imaging is a non‐invasive, non‐destructive and chemically specific imaging method widely used in medicine to reveal information about both tissue structure and function. It can measure water in tissue, but it has been difficult to achieve the necessary sensitivity and resolution when applying it to studies of the dry, thin stratum corneum. In this paper the use of magnetic resonance imaging to image the outer layers of the skin with a resolution of 0.06 mm is reported. Configuring the magnetic resonance imaging method in this way has made it possible for the first time to actually ‘see’directly the moisturization in the stratum corneum. It is no longer necessary to rely upon methods which can only show side‐effects of moisturization, such as changes in the appearance of the skin cells. As magnetic resonance imaging is harmless, it can be used repeatedly on the same skin and so produce a series of stills, or a time‐lapse video, clearly showing the actual process of moisturization and related phenomena. The behaviour of skin has been observed during both hydration and dehydration; the two processes follow different time courses. Two layers have been observed in the stratum corneum, which appear to be different when the skin is hydrated.For the first time the actual surface of normal skin has been revealed on magnetic resonance images.