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Biomedical subjects

P Corcuff

Publications and source records attributed to P Corcuff.

At least 19 recordsLinked to original sources
PubMed2001

Persistence of both peripheral and non-peripheral corneodesmosomes in the upper stratum corneum of winter xerosis skin versus only peripheral in normal skin.

To understand the biochemical abnormalities that underlie the reduced desquamation observed in dry skin, we analyzed corneodesmosome degradation in normal and winter xerosis skin. Western blotting of total proteins from corneocytes obtained by varnish-strippings from the legs of 56 volunteers with normal (26) or xerotic (30) skin was performed using antibodies specific for (corneo)desmosome proteins. In the whole population, the amounts of desmoglein 1 and plakoglobin were found to be correlated, but were not related to the amounts of corneodesmosin. This suggests simultaneous proteolysis for the former proteins differing from that of corneodesmosin. Neither entire desmoplakins nor any proteolysis-derived fragments were detected. The amounts of corneodesmosin, desmoglein 1, and plakoglobin detected were found to be significantly higher in xerotic compared with normal skin extracts. Conventional and freeze-fracture electron microscopy showed the absence of nonperipheral corneodesmosomes in the upper stratum corneum of normal skin but the presence of a significant number of these structures in the same layer of winter xerosis skin. These results provide a more precise description of the proteolysis of corneodesmosome components in the upper cornified layer of the epidermis. They support previous studies demonstrating the importance of corneodesmosome degradation in desquamation and reveal that the nonperipheral corneodesmosomes, which are totally degraded during maturation of the stratum corneum in normal skin, persist in winter xerosis, probably leading to abnormal desquamation.

Adult↗
PubMed2001

Ultrastructure of the human stratum corneum.

The ultrastructural study of the intercellular spaces of the human stratum corneum was based on transmission electron microscopy of thin vertical sections and freeze-fracture replicas, field emission scanning electron microscopy and immunofluorescence confocal laser scanning microscopy. The maturation of the corneosomes and their enzymatic degradation could be depicted at strategic interfaces. These sharp and rapid metamorphoses are now relatively well understood from a morphological point of view. But morphology raises a lot of unsolved physiological problems.

Animals↗
PubMed1997

Three-dimensional microscopic biopsy of in vivo human skin: a new technique based on a flexible confocal microscope.

A new noninvasive microscopic technique of three-dimensional optical biopsy from in vivo human skin based on real-time confocal microscopy and computer reconstruction is demonstrated. A tandem scanning confocal microscope is a prototype of a mobile, flexible design for the in-depth microscopic exploration of the skin on the human body. The various skin layers were observed in real-time, at the subcellular level down to a depth of 200 microns with a vertical resolution of 2 microns. Rapid video recording of the Z-series through the ventral aspect of the forearm avoided shifts caused by subject movement and blood flow pulsations. Two video frames were averaged, and the average was digitized, providing a stack of 64 optical sections in 1-micron vertical steps. Three-dimensional reconstructions of in vivo human skin were obtained with sets of orthogonal slices, and slices at arbitrary planes through a volume containing the stack of slices. This method clearly shows the spatial relationships between the different cell layers. The use of orthogonal cutting planes is preferred because of its analogy with classical vertical sections of histopathology. Linear structures (surface lines) within the stratum corneum are described and their global orientations were determined by the use of Fourier transform analysis. En face optical sections constitute unusual views of this tissue, since typical pathohistological studies are based on sagittal (vertical) slices. The noninvasive optical microscopic technique provides a three-dimensional optical biopsy of in vivo human skin.

Biopsy↗
PubMed1996

In vivo confocal microscopy of human skin: a new design for cosmetology and dermatology.

In-depth exploration of cellular structures in living human skin in situ is possible with the tandem scanning microscope (TSM). However, the rigid design of the microscope limited observations to the arms, hands, and fingers. A mobile version allowing the investigation of any parts of the body has been designed. The head containing the Nipkow disk and the optical path were the only part saved from the original TSM. This prototype can be used to observe, in real time, the different skin structures down to a depth of 200 microns and to measure the thickness of the different layers with micron precision level. The hydration of the stratum corneum (SC) could be assessed. For example, lengthy immersion of the hand in water led to an increase in SC thickness without affecting that of the living epidermis. Occlusive patch tests also showed that water and, even more so. propylene glycol, led to transient swelling of the SC. In dermatology, the example of psoriasis illustrated the value of the TSM for describing, measuring, and assessing pathologic skin changes. The availability of this noninvasive method for observing changes with time in a given skin site should prove useful for monitoring treatment efficacy. This tool opens up new insight for the investigation of cutaneous pathophysiology.

Cosmetics↗
PubMed1994

[Microscopic diagnosis of onychomycoses].

INTRODUCTION: The microbiological identification of onychomycosis may be uncertain as some fungi growing in culture from this material are not necessarily pathogen and invasive. Conversely, the negativity of a culture is not rare even when fungi are seen by microscopy. MATERIALS AND METHODS: We compared the information brought by standard histological examination, immunohistochemistry and in vivo confocal microscopy. RESULTS: The histological examination of nails is of importance in this pathology. We present a laboratory technique that proves to be easy and rapid. We report diagnostic criteria allowing the distinction between dermatophytes, yeasts and non-dermatophyte molds. The standard microscopic examination may further be improved by immunohistochemistry using some antibodies to fungi. In vivo confocal microscopy is a technique for the future. The dermatologist will be able to see fungi in the nail at the clinical examination, without any sampling or peculiar preparation. CONCLUSION: The histological examination is a routine technique useful for defining the nature and localization of fungi in the nail plate. Immunohistochemistry applied to onychomycosis is an experimental approach bringing prominent informations about the identification of fungi. In vivo confocal microscopy is a door opened to the future.

Arthrodermataceae↗
PubMed1993

Morphometry of human epidermis in vivo by real-time confocal microscopy.

Real-time confocal microscopy has brought substantial improvements to the imaging of the human skin in vivo. On early images, the stratum corneum could be distinguished from the living epidermis and the circulatory network of the superficial dermis. We have adapted the Tandem Scanning Microscope to obtain images of the living skin, showing thinner structures such as the stratum lucidum and the dermo-epidermal junction, both of which are essential markers for micron-order measurements of the thickness of the stratum corneum and living epidermis. The measurements were corrected for the differences in the refractive index of the various cutaneous layers, and the undulation of the dermo-epidermal junction. Furthermore, nucleus size and number could be assessed from horizontal optical sections. To illustrate the sensitivity of the thickness measurements, changes in the thickness of the epidermis were recorded during and after stripping of the horny layers. This non-invasive methodology is a very promising tool for morphometric studies of the living human skin at the cellular level.

Epidermal Cells↗
PubMed1993

High-spatial-resolution maps of sulphur from human hair sections: an EELS study.

High-resolution sulphur maps have been acquired from human hair using a Zeiss CEM 902A transmission electron microscope equipped with an energy filter. Analysis by electron energy-loss spectroscopy (EELS) was performed on ultrathin sections of hair shafts embedded in three different types of resin: Nanoplast (water-soluble), Spurr (epoxy) and Lowicryl (low-temperature resin). Good-quality energy-loss images have been obtained with the three resins, although it was found that Nanoplast gave the best image contrast. For the first time, the results obtained for the detection of sulphur by silver staining of hair sections, which until now has been the only way to map sulphur at the electron microscopic level, have been confirmed. The results are compared with local sulphur concentrations from bulk analysis.

Hair↗
PubMed1993

In vivo vision of the human skin with the tandem scanning microscope.

The tandem scanning reflected light microscope invented by Petran and Hadravsky provides real-time vision in the confocal mode. It performs nondestructive optical sectioning of biological material to a depth that depends on the transparency of the tissue. This real-time facility adds a fourth dimension (time) to the study of living specimens. In the present work, human skin was explored in vivo, at the cellular level to a depth of 150 microns. Two different anatomical sites were investigated: the back of the hand and the volar aspect of the forearm. The stratification of the horny layers, the nuclei of the living keratinocytes through the whole epidermis and the capillary loops within the superficial dermis constituted clear reference points. These permitted thickness measurements of the stratum corneum and epidermis to an accuracy of 1 microns. This method of exploration provides a new challenge for dermatologists and cosmetologists.

Epidermal Cells↗
PubMed1991

Extension-induced changes in the microrelief of the human volar forearm: variations with age.

The skin microrelief can be assessed in vivo using a noninvasive method based on the image analysis of negative replicas, shadowed by oblique illumination. This technique was used to study changes in the surface furrows of the human volar forearm, related to the degree of extension, in volunteers of three age groups. Results confirmed that the skin in elderly subjects can be characterized by the lack of one of the two perpendicular furrow orientations observed in the young. During extension of the arm, the response of the microrelief in young subjects was clearly different from that in the elderly. Young skin buffered strain through a progressive shift in line density and furrow depth from one orientation to the other, whereas in the elderly, a progressive rotation of the single furrow orientation occurred. These differences would appear to be related to changes in the architecture and physical properties of the dermis. Microrelief, in the elderly subjects, showed a mean line density of 24/cm, regardless of the degree of extension. This constancy may reflect the ultimate stage in the chronological aging of the skin and may be characteristic of a loosened and relaxed dermis.

Adult↗
PubMed1991

Racial differences in corneocytes. A comparison between black, white and oriental skin.

It is well known that spontaneous desquamation and corneocyte size can reflect respectively stratum corneum cohesiveness and epidermal cell proliferation. The influence of skin pigmentation on these parameters has been investigated on the upper-outer arm of black, white and oriental volunteers, using the detergent scrub method. We found no difference between race in corneocyte surface area, a mean size of 900 microns 2 agreeing closely with that generally encountered in Whites on the upper-outer arm. By contrast, spontaneous desquamation is increased in black vis-à-vis white and oriental skin (factor 2.5, p less than 0.001). Taking into account the importance of the intercellular cement for the cohesion between corneocytes, racial differences in epidermal lipid composition should be investigated.

Adult↗
PubMed1990

Alterations in the composition of human stratum corneum lipids induced by inflammation.

Changes in the composition of human stratum corneum lipids (SCL) were studied at various times after an induced inflammatory reaction. Three kinds of injury were inflicted: 3 MED of ultraviolet radiation, 3 MED of solar radiation or 30 strippings of the horny layer with plastic tape. The SCL were evaluated qualitatively and quantitatively at short intervals. Marked changes in the SCL were detected between the 9th and the 11th day. With all 3 insults, the SCL increased quantitatively and showed a more polar pattern, i.e. a decrease in neutral fractions and an increase in the polar ones. These changes were synchronous with the marked shedding which occurs between the 9th and the 11th day. These findings have implications for the role of lipids in stratum corneum cohesiveness.

Adolescent↗
PubMed1989

A method for measuring the various constituents of the human hair follicle.

Hair follicles from scalp biopsies (temporal and parietal regions) were isolated by microdissection. This technique allows preservation of the whole structure of the follicle in its fibrous sheath, or isolation of certain elements: bulb and dermal papilla. Each follicle is examined by transmission optical microscopy and its image is digitized into sixty-four grey levels by an image analyser. Follicle images are memorized on a hard disc, then recalled individually for measurement. The image analysis consists of thresholding, interactive selecting, then measurement of the following elements: diameter of the hair follicle, volume of the bulb, height of the keratogenous zone, mean diameter of the hair and size of the dermal papilla. These parameters were related to a clinical classification (terminal, dystrophic, vellus). This morphometric study constitutes an objective approach which is different from, but complementary, to the classic trichogram (telogen/anagen).

Adult↗
PubMed1988

Corneocyte changes after acute UV irradiation and chronic solar exposure.

The effects of UV irradiation on the human stratum corneum (SC) were studied under both artificial and natural conditions. Artificial UV exposure was performed with a solar simulator. Single doses of radiation from 1 to 3 MED were delivered on the backs of volunteers and the measurements were recorded for a period of one month. Corneocytes were harvested from the skin surface by using a "turbine-machine". Their count and projected area were measured by image analysis. The evolution of corneocyte counts showed 3 steps: 1) a background level of desquamation until the 8th day; 2) a sharp increase from day 9 to day 11; and 3) a plateau until the 20th day. No evolution of the corneocyte size occurred at 1 MED, but a decrease was recorded at day 20 for 2 MED and earlier for 3 MED. Natural sun exposure was investigated in 2 different experiments: on a population living in a sunny coastline and on professional racing cyclists. In these natural conditions, the response of the SC to UV led to an increase in corneocyte count associated with a decreased size. Even though natural environment involves both weather and sun influences, results showed similar SC responses. In case of acute irradiation, the skin recovers its initial state one month later, but in the natural environment, it maintains altered features as long as the UV irradiation occurs.

Adult↗
PubMed1988

Microrelief changes in chronically sun-exposed human skin.

The effects of solar exposure on the microtopography of the human skin can be followed, in vivo, by comparing 2 nearby areas, protected and non-protected, of the arm. This has been possible in the case of professional cyclists, whose short-sleeved outerwear provides a clear demarcation of the 2 zones. The microrelief was measured from negative replicas by an automatic image analysis method. The skin pattern showed clear changes between the 2 zones. Results are discussed in an attempt to outline similarities and differences between the effects of the actual aging process and solar radiation.

Adult↗