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Biomedical subjects

L Dubertret

Publications and source records attributed to L Dubertret.

At least 325 records · Page 18Linked to original sources
PubMed1982

Neutrophil studies in psoriatics: in vivo migration, phagocytosis and bacterial killing.

A reproducible method for sequential study of migration out of human skin, phagocytosis and bactericidal activity of neutrophils is described. Untreated psoriatics exhibit an early increase of chemotactic activity (0-8 hr, p less than 0.02) and subsequently a strong inhibition of chemotaxis (8-24 hr, p less than 0.01), a slight decrease of phagocytosis and a decrease in bactericidal activity (20 min, p less than 0.02; 30 min, p less than 0.003); 60 min, p less than 0.001; 120 min, p less than 0.001) as compared with controls. After clearing of skin lesions, the early increased chemotactic activity returned to normal values but the subsequent chemotactic inhibition remains as strong as before treatment. Phagocytosis increased to normal values (p less than 0.02) and bactericidal activity also increased but remained significantly low. These abnormalities were more evident in migrating than in circulating neutrophils, underlining the sensitivity of the described method.

Adult↗
PubMed1982

Diaminobenzidine cytochemistry in unfixed human epidermis: a marker for epidermal differentiation and for mitochondria.

Intubation of unfixed and unfrozen slices of skin in diaminobenzidine allows visualization of a peroxidatic activity in perinuclear envelope of suprabasal keratinocytes undergoing orthokeratotic differentiation. Basal keratinocytes and melanocytes are always negative. This enzyme is absent in mucous and parakeratotic (psoriatic) differentiation. Mitochondria are also strongly stained by this technique and it was shown that the number of epidermal mitochondria is greatly increased in psoriatic lesions.

3,3'-Diaminobenzidine↗
PubMed1982

A cytochemical marker for epidermal differentiation, Langerhans cells, skin resident macrophages and mitochondria.

Incubation of unfixed and unfrozen slices of skin in diaminobenzidine allows visualization of peroxidatic activity in the perinuclear envelope and endoplasmic reticulum of normal human Langerhans cells. A similar peroxidatic activity is observed in supra-basal keratinocytes undergoing orthokeratotic differentiation. Basal keratinocytes and melanocytes are always negative. This enzyme is absent in mucous and parakeratotic (psoriatic) differentiation. A peroxidatic activity was also found in the endoplasmic reticulum of normal resident skin macrophages. Mitochondria are also strongly stained by this technique and it was shown that the number of epidermal mitochondria is greatly increased in psoriatic lesions.

Cell Differentiation↗
PubMed1981

Secondary ion emission microanalysis: applications to the study of human skin.

Secondary ion emission microanalysis is a new method of physical analysis recently applied in biology. The apparatus required (CAMECA SMI 300) enables pictures to be taken of the distribution of certain elements, with a space resolution of the order of 1 microgram. Concentrations below 1 p.p.m. are perceptible for most elements. The present results are the first obtained for human skin sections. Investigation of the natural elements of normal skin reveals no particular accumulation. Elements foreign to the skin are easy to detect. We show here the distribution in the epidermis of clinical antiseptics applied locally. This method has two advantages compared to X-ray microanalysis. It is more sensitive and allows analysis of even the lightest elements. However, its use in skin penetration studies is limited because it does not permit quantitative analysis and serious interference problems may occur.

Anti-Infective Agents, Local↗
PubMed1981

Autoradiographic localization of 8-methoxypsoralen in psoriasis skin in vitro.

Slices of psoriatic (Pso) skin were incubated with tritiated 8-methoxypsoralen (8-MOP) and exposed to UVA irradiation. The photobinding of 8-MOP was studied by autoradiography at the cellular level and in the different layers of the epidermis and in the dermis. Silver grains were found in the nucleus and the cytoplasm of the various cell types. Keratin, collagen and lipoproteins were also labelled. The upper malpighian cells and the parakeratotic cells showed a greater degree of labelling than did the basal layers. In skin incubated with [3H]8-MOP and unirradiated, no measurable labelling was detected. These results suggest that the targets responsible for the therapeutic activity of 8-MOP might be not only nucleic acids, but also proteins.

Autoradiography↗