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Biomedical subjects

M Paye

Publications and source records attributed to M Paye.

25 records · Page 2Linked to original sources
PubMed1986

The lack of attachment of transformed embryonic lung epithelial cells to collagen I is corrected by fibronectin and FXIII.

PER cells, a transformed pulmonary epithelial cell line that adhered to a large extent to a fibronectin substratum, were found to be attachment-deficient to collagen I. Although fibronectin can bind to collagen I monomers and polymers, the addition of exogenous fibronectin in the attachment medium induced the adhesion of these cells to collagen I polymers but not to monomers. By adding the transglutaminase of blood coagulation, FXIII, in the presence of fibronectin, the attachment of PER cells to collagen I monomers could be recovered while the minimal concentration of fibronectin needed to promote their adhesion to polymers was lowered. These studies indicate that FXIII enhances the fibronectin-mediated attachment of PER cells to collagen I.

Animals↗
PubMed1984

Preparation and characterization of monoclonal antibodies against phenobarbital-inducible cytochrome P-450.

Monoclonal antibodies against cytochrome P-450 were prepared from phenobarbital-induced rat liver microsomes. The immunoglobulin classes and subclasses, as well as the binding capacity to cytochrome P-450, of the different antibodies were characterized. Their specificity was verified by various techniques and seemed to correspond to a single form of cytochrome P-450, the major phenobarbital-inducible form. However, the antibodies were unable to inhibit completely the monooxygenase activities investigated. These antibodies may constitute very specific and powerful analytical tools for characterizing and quantifying cytochrome P-450 isoenzymes.

Animals↗
PubMedDate not supplied

EEMCO guidance for the in vivo assessment of skin greasiness. The EEMCO Group.

Sebaceous gland activity has four distinct components which are sebum production (a secretion rate function), storage (a volume function), surface output (a delivery rate function) and stratum corneum permeation (an influx rate function). The oily appearance of skin results from an excess of sebum excretion and spreading over the body surface and its interaction with the skin surface. A multi-pronged approach is often useful to assess skin greasiness with precision. The clinical evaluation of skin greasiness and its shiny appearance should be further complemented by quantifying the large pores, follicular plugs and comedones. The sebum amount present at the skin surface can be measured non-invasively using one of several methods based on solvent extraction, cigarette paper pads, photometric assessment, bentonite clay and lipid-sensitive tapes. Quantitative parameters include the sebum casual level, the sebum excretion rate, the sebum replacement time, the instant sebum delivery, the follicular excretion rate, the density in sebum-enriched reservoirs and the sustainable rate of sebum excretion. A series of environmental and biological features influence the data. Hence rigorous methodological designs are mandatory to support claims. As a rule, accuracy of the methods is adversely affected by skin temperature, degree of hydration and surface roughness. An additional confounding factor is the inherent difficulty of collecting the surface lipids without a contribution from the follicular reservoir. A better understanding of factors that alter the sebum amount at the skin surface may well assist in the development of sebosuppressive agents to help the reduction of the skin greasiness and improve acne.

Humans↗
PubMedDate not supplied

EEMCO guidance for the in vivo assessment of skin surface pH.

The pH of the skin follows a sharp gradient across the stratum corneum (SC), which is suspected to play an important role in controlling the enzymatic activities involved in cellular metabolism and renewal. This gradient is maintained by several systems, such as sweat and sebum secretion and degradation as well as cellular metabolism. At the surface of the skin, what is measured is in fact an apparent skin pH due to extracted material from the SC diffusing into water applied at the surface. pH values recorded at the surface of a semi hydrophobic milieu such as the SC should be interpreted with great caution because it is obvious that hydrogen ions are not in a pure solution at the surface of the skin. For a correct measurement of skin surface pH, it is recommended to follow all practical operating conditions. Care must be taken in identifying the skin site, healthy controls (age, gender, skin type), the time of day of the measurement and the environmental conditions. Also, subjects should receive precise instructions before the test, mainly in terms of hygiene procedure or use of topical products. The interpretation of data should not overlook the fact that even small differences in pH may reflect significant modifications at the molecular level. Although it is usually agreed that the pH of the skin surface may influence the cutaneous microflora, much remains to be learnt about the role of the acid mantle of the skin with regard to defensins and other protective mechanisms.

Epidermis↗
PubMedDate not supplied

EEMCO guidance for the efficacy assessment of antiperspirants and deodorants.

Overproduction of sweat, sweaty skin and body odours are unpleasant for many social groups. Body cleansing products are designed to combat these undesirable features of skin. In addition, antiperspirant and deodorant products are more specifically used in the underarm site by a large part of the adult population. Antiperspirants are offered to control emotionally triggered sweating in the armpit. Deodorants are designed to combat malodour generated from bacteria-modified sweat. This review summarizes the physiology of eccrine, apocrine and apoeccrine sweat glands. The mechanisms of action of antiperspirants and deodorants are described as well as the factors influencing their efficacies. A series of tests using various measurement methods can be used to demonstrate the efficacy of antiperspirants. These include the gravimetric method, water evaporation quantification, electrodermal measurements, staining procedures, dye injections and cyanoacrylate skin surface strippings and casting replicas. Deodorant efficacy can be evaluated by sensory assessments performed by an expert panel. Indirect support is provided by visualization of apocrine gland excretion and collection of sweat and volatile compounds. Microbiological assessments and chromatographic analysis also provide indirect information.

Apocrine Glands↗