Fragility of epidermis and its consequence in dermatology.

The skin is the largest organ of the body, providing a protective barrier against bacteria, chemicals and physical insults while maintaining homeostasis in the internal environment. Such a barrier function the skin ensures protection against excessive water loss. The skin's immune defence consists of several facets, including immediate, non-specific mechanisms (innate immunity) and delayed, stimulus-specific responses (adaptive immunity), which contribute to fending off a wide range of potentially invasive microorganisms. This article is an overview of all known data about 'fragile skin'. Fragile skin is defined as skin with lower resistance to aggressions. Fragile skin can be classified into four categories up to its origin: physiological fragile skin (age, location), pathological fragile skin (acute and chronic), circumstantial fragile skin (due to environmental extrinsic factors or intrinsic factors such as stress) and iatrogenic fragile skin. This article includes the epidemiologic data, pathologic description of fragile skin with pathophysiological bases (mechanical and immunological role of skin barrier) and clinical description of fragile skin in atopic dermatitis, in acne, in rosacea, in psoriasis, in contact dermatitis and other dermatologic pathologies. This article includes also clinical cases and differential diagnosis of fragile skin (reactive skin) in face in adult population. In conclusion, fragile skin is very frequent worldwide and its prevalence varies between 25% and 52% in Caucasian, African and Asian population.

Extracorporeal photopheresis as a curative treatment strategy in non epidermotropic T-cell lymphoma and large granular lymphocyte leukemia.

BACKGROUND: To evaluate the efficacy of extracorporeal photopheresis (ECP) in noncutaneous T-cell lymphoma and large granular lymphocytes leukemia (LGL). PATIENTS AND METHODS: We have treated 12 refractory/relapsed patients. Six peripheral T-cell lymphoma (PTCL), one T-lymphoblastic lymphoma and five LGL with blood involvement received six biweekly leukapheresis as induction phase, followed by one course a week for 4 weeks as consolidation and one course of maintenance per month for responders until progression/relapse or disappearance of the peripheral clone. RESULTS: Six patients responded to phototherapy. Two PTCL and two LGL achieved a complete response (CR) and two other PTCL a partial response. The median duration of CR was 117 months (45-150 months) for these four patients. The peripheral clone followed by flow cytometry decreased in all six responders. Two patients with a complete disappearance of the peripheral clone have not relapsed. CONCLUSIONS: As for cutaneous T-cell lymphoma, ECP therefore to be efficient for PTCL and LGL. Early decrease and disappearance of the peripheral clone were the indicators of clinical response and nonrelapse, respectively.

Modulating effects of oatmeal extracts in the sodium lauryl sulfate skin irritancy model.

The aim of the present study was to assess the anti-inflammatory activity of two topically applied oatmeal extracts, i.e. Avena sativa and Avena Rhealba, using the sodium lauryl sulfate (SLS) irritation model. At baseline, test areas on the volar surface of the upper arms of 12 healthy individuals were pretreated with the two extracts and their vehicle (petrolatum ointment) under occlusion for 2 h, and one site was left untreated. Then a patch with a 1% SLS solution was applied to the test sites for 24 h. Irritation was determined at each period by measuring by chromametry and laser-Doppler. In a dose-ranging study with the Avena Rhealba extract alone, the 20 and 30% concentrations exerted a slight inhibition of the a* parameter increase and a marked reduction of the blood flow increase (p < 0.05, compared to vehicle). Then, the effects of the two extracts at the concentration of 20% were compared. All extracts displayed a statistically significant counteracting effect on both parameters (p < 0.05), but no statistically significant difference between treatment groups could be demonstrated. In conclusion, this study demonstrates the preventive effects of oatmeal extracts on skin irritation in the SLS model.

A simple screening method for insecticidal substances from actinomycetes.

A simple and selective assay system was developed in the search for new insecticidal substances from Actinomycetales strains propagated on solid culture media. The strains were first tested for their ability to produce antimicrobial compounds. Only strains displaying weak or no activity were retained and screened in the insecticidal bioassay. Microbial solid cultures were given as food to larvae and to adults of Musca domestica to detect insecticide producers. A second phase, after extraction of the active compounds, consisted of an evaluation of the insecticidal potency and a primarily biological identification of the products synthesized by the selected strain. Of 6,280 actinomycete strains which were screened, 47 were active but only 30 of these were finally chosen in the second phase of screening. All these strains, except one, produced known metabolites such as piericidins, avermectins or valinomycin. The one strain, CL307-24, and its insecticide products appeared novel and will be the topic of further study.