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Biomedical subjects

M Paye

Publications and source records attributed to M Paye.

At least 19 recordsLinked to original sources
PubMed2001

Subclinical, non-erythematous irritation with an open assay model (washing): sodium lauryl sulfate (SLS) versus sodium laureth sulfate (SLES).

Compared to exaggerated hand washing procedures, an open non-exaggerated assay better approximates consumer surfactant use. Our goal was to observe skin surface modifications induced by an open test with regard to discriminating between surfactant solutions. This human in vivo assay provided information about the effect of only three washes at the laboratory and a week of at-home use. Dorsal hand and volar forearm were compared. The results demonstrated that this clinical model permits exploration of subclinical surfactant-induced irritation. Both the volar forearm and the dorsal hand are capable of discriminating between the effects of sodium lauryl sulfate (SLS) and sodium laureth sulfate (SLES). Squamometry proved to be a sensitive assessment technique for detecting surfactant-induced subclinical skin surface alterations and for differentiating surfactant effects in this open application assay, in as few as three washes.

Adult↗
PubMed2001

Hand and forearm skin: comparison of their respective responsiveness to surfactants.

BACKGROUND/AIMS: Skin compatibility of detergent products is usually evaluated using predictive tests where products are applied on the back or the forearm of the volunteers, even if those products come more readily into contact with consumers' hands. The current study aimed at comparing the skin responsiveness of hands and volar and dorsal forearms to a surfactant solution. METHOD: Volunteers soaked simultaneously their forearms and hands in a solution of anionic surfactants, at 40 degrees C for 20 min, thrice a day and for 2 consecutive days. Skin condition on the hands, and the volar and dorsal forearms was evaluated by clinical examination and instrumental measurements. RESULTS: Significant differences were observed at baseline for various skin parameters, especially those related to skin dryness. After repetitive contacts with the surfactant solution, a parallel evolution of most skin parameters was observed--i.e., an absence of change in instrumentally measured erythema and transepidermal water loss, a similar decrease in corneometry values, and a similar increase in staining of the stratum corneum strippings and in clinical dryness. However, an opposite effect of the soakings on the cohesiveness between corneocytes harvested by tape strippings from hand and forearm was observed. CONCLUSION: For most parameters, skin responsiveness to surfactants appears to be quite similar on the hands and forearms. It is inferred that forearms can be conveniently used to predict interaction of surfactants with hands.

Adult↗
PubMed2001

A comparative study of the effects on the skin of a classical bar soap and a syndet cleansing bar in normal use conditions and in the soap chamber test.

BACKGROUND/AIMS: The skin irritation potential of a body cleansing product is often compared under exaggerated test conditions, although the product is intended to be used at home with repetitive and brief contact with the skin. The aim of this study was to determine how much patch testing is predictive of the clinical, sub-clinical and subjective cutaneous effects of products used at home by consumers for their normal hygienic cleansing. METHODS: A double-blind comparative study of the normal use of an alkaline soap bar and a syndet at home during 10 consecutive weeks was performed on two identical groups of 25 healthy female subjects. The eventual skin changes observed at different anatomical skin sites were evaluated by clinical visual examination and by bioengineering measurements before the start of the study and then every 2 weeks. The objective measurements were compared with the subject's perceptions of dryness, tightness and product irritancy during the testing. RESULTS: The bioengineering measurements did not show any significant changes on all the anatomical skin sites, except for a small increase in skin pH with the classical soap bar. However, a trend appeared, showing that the alkaline soap bar is perceived by the subjects themselves as more of an irritant than the syndet bar. In the soap chamber test, the bar soap showed a significantly higher irritancy than the syndet bar. CONCLUSION: This study showed that cutaneous irritation induced by cleansing products in patch testing is not necessarily predictive of the irritation likely to occur in normal use conditions. Finally, a clear relationship could be demonstrated between the results of the soap chamber test and the consumer perception of both cleansing bars.

Adult↗
PubMed2000

An open assay model to induce subclincal non-erythematous irritation.

To avoid the acute irritation and dryness that a single occlusive surfactant application (24-h patch test) may cause, and to approximate clinical use, an open application model was chosen to define subclinical non-erythematous irritation in the stratum corneum. This human test combined a supervised washing at the laboratory with at-home use of the test products by the subjects. Effects of washing with the surfactants on the dorsal hand and volar forearm were compared. The results demonstrated that this situational use model permits the exploration of subclinical surfactant-induced irritation. The forearm appeared to be more discriminative as compared to the dorsal hand. Squamometry proved to be a sensitive, complementary assessment method for detecting surfactant-induced subclinical skin surface alterations and for differentiating surfactant effects in this open assay.

Adult↗
PubMed1999

A hand immersion test under laboratory-controlled usage conditions: the need for sensitive and controlled assessment methods.

Exaggerated test conditions were frequently used to investigate the cutaneous tolerance of detergent products in the past. As the sensitivity of newly designed biometric methods is steadily improving, the trend towards more realistic test conditions should be encouraged. A hand immersion test under laboratory-controlled usage conditions is presently described, fulfilling such principles. Panelists soaked their hands in 2 different hand dishwashing liquids, 2x daily for 10 min each (with successive in-solution/out-of-solution cycles) for 4 consecutive days. Products were at usual dilution for dishwashing liquids and were randomized between the dominant and non-dominant hands of panelists. Visual scoring of erythema and dryness developing on the whole hands (scoring scales including interdigital areas and joints) during the week did not allow discrimination between the 2 products. However the dominant hands were significantly more susceptible to alterations than the non-dominant hands, regardless of product attribution. In contrast, skin electrical measurements (Corneometer CM800 and Skicon 200) on the dorsum of the hands (muscle mass between thumb and index) and squamometry analysis of tape stripping (harvested from the same site) yielded significant differences between the 2 products. In conclusion, a hand immersion test under realistic conditions has been described, which discriminates between products when sensitive assessment methods are used to explore skin sites partially protected from daily-life skin aggressions.

Allergens↗
PubMed1998

Sensitive skin at menopause; dew point and electrometric properties of the stratum corneum.

OBJECTIVE: A number of menopausal women experience skin sensitive to various environmental threats. METHOD: Two panels of 15 menopausal women on or without HRT were compared. We studied the response of their stratum corneum to variations in environmental humidity, either in air or in response to an emollient. Environment dew point and electrometric measurements on the skin were recorded to search for correlations. RESULTS: Data show that the baseline stratum corneum hydration is influenced by the dew point. HRT improves the barrier function of the skin. The use of emollient further extends the improvement in the functional properties of skin in menopausal women. CONCLUSION: Both HRT and an emollient can counteract in part some of the deleterious effects of cold and dry weather.

Epidermis↗
PubMed1995

Comparison of in vitro predictive tests for irritation induced by anionic surfactants.

Skin compatibility of anionic surfactants may often but not always be predicted by in vitro tests. For instance, the correlation between in vivo and in vitro data is classically hampered in the presence of magnesium. This ion is known to interfere with in vitro skin irritation predictive tests based on protein denaturation. This study was conducted to compare a recently introduced assay, corneosurfametry, with other in vitro tests including the pH-rise of bovine serum albumin, collagen swelling, and zein solubilization tests. Corneosurfametry entails collection of cyanoacrylate skin surface strippings and short contact time with surfactants, followed by staining samples with toluidine blue and basic fuchsin dyes. Measurements are made by reflectance colorimetry. Data show that irritation potentials predicted by corneosurfametry agree with those obtained by established in vivo and in vitro irritation tests. Moreover, corneosurfametry data are not artificially lowered by addition of magnesium in surfactant solutions. In conclusion, corneosurfametry should be viewed as one of the realistic predictive tests for surfactant irritancy.

Collagen↗
PubMed1994

Dansyl chloride labelling of stratum corneum: its rapid extraction from skin can predict skin irritation due to surfactants and cleansing products.

The irritation potential of surfactants and body cleansing products was determined by evaluating the removal of dansyl chloride from the skin. Dilute solutions (2% active ingredient, w/v) of surfactants and soap extract fluorescence from the skin within 30 min. This is probably a physicochemical effect as it is too rapid to be due to a modification of epidermal cell turnover rate. Such an extraction of the fluorescent dye occurs without any clinical sign of irritation. However, it may represent an early phase of the skin irritation process, because it is related to the ranking of irritant products as determined by other assessment methods.

Betaine↗
PubMed1991

Factor XIII of blood coagulation decreases the susceptibility of collagen precursors to proteolysis.

Factor XIII, the transglutaminase of blood coagulation, was found to reduce the susceptibility of collagen precursors synthesized by skin fibroblasts in vitro to proteolytic activity. Several hypotheses for the mechanism of action of FXIII are proposed. One of them is the self-association of collagen precursors as well as their association with other proteins present in the serum or synthesized by fibroblasts to form a high molecular weight complex. This complex contains, among others, collagen I and partially processed precursors (alpha 1, alpha 2, pN-alpha 1, and pN-alpha 2 chains), collagen III and its precursors (alpha 1 and pN-alpha 1 chains), fibronectin and FXIII. This study indicates that FXIII modifies the structural organisation of the synthesized products of fibroblasts and may partially protect them against proteolytic degradation.

Animals↗
PubMed1991

Utilization of human cultured epidermal keratinocytes: irreversibility of the inhibition of proliferation induced in stored detached cultures.

In order to look for the best conditions required for the utilization of cultured epithelium in the treatment of burn wounds, some experiments have been performed studying the storage of dispase-detached cultures. The viability of keratinocytes and, after trypsin dissociation of the cultures, the adhesion and proliferative potential of living keratinocytes were measured. Our laboratory investigations suggest that the storage period of detached cultures has to be kept as short as possible to preserve the keratinocytes' growth potential.

Burns↗
PubMed1990

Factor XIII in scleroderma: in vitro studies.

The administration of Factor XIII (FXIII) produces a beneficial effect on the skin lesions in about 50% of the treated patients with progressive systemic sclerosis (PSS). The effect of FXIII on various skin fibroblast functions (proliferation, attachment, biosynthetic activity and mechanical properties) was investigated in vitro using normal and PSS strains. In cell culture, most of the PSS fibroblast strains synthesized excessive amounts of collagen. Other cell functions such as adhesion to collagen I or III, to fibronectin, retraction of collagen lattices, proliferation in low serum concentration and degradation of newly synthesized collagen were not significantly different. The addition of FXIII (I U/ml) inhibited the synthesis of collagen by normal fibroblasts and reduced it in PSS fibroblasts to a level similar to that of normal fibroblasts. This effect was observed for cells cultured on plastic or in a collagen lattice. In the latter, an increased amount of collagen degradation was observed. No significant effect of FXIII on the other cell functions was noted. Excessive collagen production by PSS fibroblasts can be repressed by FXIII in vitro by at least two distinct mechanisms: a reduction of collagen synthesis and an increased degradation of the newly synthesized collagen.

Adult↗
PubMed1989

Factor XIII of blood coagulation modulates collagen biosynthesis by fibroblasts in vitro.

The effect of activated factor XIII (FXIIIa), the transglutaminase of blood coagulation, on some cellular functions was studied in skin and lung fibroblasts in vitro. FXIIIa repressed the overall protein synthesis and mainly collagen synthesis in a concentration-dependent manner and induced modifications in the proportion of the different types of newly synthesized collagen. The repression of collagen synthesis occurred in cells cultured on plastic (-40%), on coated fibronectin (-53%), on coated collagens (-38%) and within a collagen lattice (-16%). Preincubation of the cells with FXIIIa and labelling in its absence also resulted in such an inhibition. However, when embedded into a fibrin lattice cross-linked by FXIIIa, fibroblasts displayed a higher biosynthetic activity than in untreated fibrin gel. These results suggest that FXIIIa acts through a modulation of the cell-matrix interactions.

Animals↗
PubMed1987

Modulation of cellular biosynthetic activity in the retracting collagen lattice.

When included in a free floating collagen lattice, several types of cells and fibroblasts attach to the collagen polymers, retract the gel, and their biosynthetic activity is repressed. Under similar conditions transformed pulmonary epithelial rat (PER) cells are unable to attach to the fibers and to significantly retract the lattice. Retraction can be induced by adding fibronectin (fn) and factor XIII (FXIII) together. This effect is fibronectin dose dependent and observed with a maximum efficiency for FXIII concentrations of 0.1 U/ml and above. Fibronectin or FXIII alone has only a limited effect on retraction. This experimental model allowed us to study the biosynthetic activity of PER cells under various degrees of cell interaction (control less than FXIII less than fn less than fn + FXIII) with their three-dimensional collagen support. The more the cells interacted with their support and retracted the gel, the more protein and collagen synthesis were reduced. This effect was observed for the products deposited in the cell layer and for those released in the medium. Increasing collagen concentration in a nonretracting lattice to a final density obtained in a maximally retracted lattice resulted in a much lower repression of biosynthetic activity. Fn and FXIII added at the same concentrations in monolayer cultures did not produce significant modification in biosynthetic activities. We propose that the regulation of the biosynthetic activity of adherent cells contracting the lattice is related to mechanical information resulting from the interactions between the cells and their support.

Animals↗
PubMed1986

Defective attachment of dermatosparactic fibroblasts to collagens I and IV.

Attachment of fibroblasts from dermatosparactic sheep and cattle to collagenous substrates (types I and IV) is defective (30-50%) when compared with fibroblasts from normal or heterozygous animals. The difference was independent of the amount of substrate, incubation time and protein synthesis. No differences were observed in the binding to fibronectin or laminin. Reduced attachment to collagen can be partially restored by adding fibronectin. The polygonal morphology of dermatosparactic cells was, however, not altered by attachment and growth on dishes coated with different collagens or fibronectin. Reduced interaction with collagens could be due to changes in specific receptors and may represent a further pathological change in dermatosparactic animals.

Animals↗
PubMed1986

Characterization of a spontaneously transformed pulmonary embryonic rat (PER) epithelial cell line.

A spontaneously transformed pulmonary embryonic rat epithelial cell line (PER) is described in terms of growth, tumorigenicity, growth factor responsiveness and biosynthetic capacity. At low-passage subcultures, PER cells grew as a monolayer and did not form colonies in soft agar. After long-term subcultivation, they lost contact inhibition, became anchorage-independent and formed tumours in nude mice. Low concentrations of foetal calf serum permit the maximum growth rate. The multiplication and metabolic activity, assessed by 2-deoxy-D-glucose uptake, was significantly stimulated by growth factors. PER cells synthesized collagen types I, III, IV and V, laminin and fibronectin, and organized a pericellular matrix made up of only basement membrane components (type IV collagen and laminin) and fibronectin. These data enabled us to define PER cells as a transformed epithelial cell line evolving towards malignancy with long-term subcultivation. These cells appeared to be a valuable tool in studies of tumour cell-matrix interactions and regulation of growth factor receptors in tumorigenesis.

Animals↗