Bertha Torres-Álvarez

Correlation between pH and irritant effect of cleansers marketed for dry skin.

Background Although it is important that dermatologists and the general population know the irritation potential of products marketed for dry skin used for body cleansing, this information is not usually available.

Histochemical and immunohistochemical study in melasma: evidence of damage in the basal membrane.

The pathogenesis of melasma has not been clearly elucidated. Using Fontana Masson; diastase-resistant periodic acid-Schiff stains; and immunohistochemistry to stem cell factor (SCF), its receptor c-kit, anti-mast cell tryptase, and anti-collagen type IV antibody, we evaluated melasma lesions and compared them with perilesional skin and photoprotected skin. Samples were taken from lesional and photoprotected nonlesional skin in 24 patients. In other 24 patients, we took biopsies of lesional and perilesional skin. With Fontana Masson, we observed many pigmented basal cells protruding into the dermis of the melasma skin. Periodic acid-Schiff stain and anti-collagen type IV showed damage on the basal membrane in 95.5% and 83%, respectively, in melasma lesion. The immunoreactivity of SCF and the prevalence of mast cells were increased in the dermis of melasma compared with perilesional dermis. The expression of c-kit was significantly increased at lesional epidermis; a frequent protrusion of c-kit-positive basal cells into the dermis was evident in 70% versus that in 29% of perilesional skin. The expression of c-kit was increased at lesional dermis of melasma compared with perilesional skin. We found a low correlation between c-kit expression and prevalence of mast cells; these were increased in melasma skin. The results may suggest a role of SCF, c-kit, and mast cells in the pathogenesis of melasma. We were surprised by the unexpected evidence of damage to basal membrane (BM), which could facilitate the fall or the migration of active melanocytes and melanin into the dermis allowing the constant hyperpigmentation in melasma.

A Double-Blind, Randomized Clinical Trial of Niacinamide 4% versus Hydroquinone 4% in the Treatment of Melasma

Background. Multiple modalities have been used in the treatment of melasma with variable success. Niacinamide has anti-inflammatory properties and is able to decrease the transfer of melanosomes. Objective. To evaluate the therapeutic effect of topical niacinamide versus hydroquinone (HQ) in melasma patients. Patients and Methods. Twenty-seven melasma patients were randomized to receive for eight weeks 4% niacinamide cream on one side of the face, and 4% HQ cream on the other. Sunscreen was applied along the observation period. They were assessed by noninvasive techniques for the evaluation of skin color, as well as subjective scales and histological sections initially and after the treatment with niacinamide. Results. All patients showed pigment improvement with both treatments. Colorimetric measures did not show statistical differences between both sides. However, good to excellent improvement was observed with niacinamide in 44% of patients, compared to 55% with HQ. Niacinamide reduced importantly the mast cell infiltrate and showed improvement of solar elastosis in melasma skin. Side effects were present in 18% with niacinamide versus 29% with HQ. Conclusion. Niacinamide induces a decrease in pigmentation, inflammatory infiltrate, and solar elastosis. Niacinamide is a safe and effective therapeutic agent for this condition.

Presence of activated lymphocytes in the peripheral blood of patients with halo nevi

BACKGROUND The involution of the central pigmented lesion in halo nevus (HN) seems to be mediated by an immune response against self antigens expressed by melanocytes. OBJECTIVE We assessed the presence of activated lymphocytes in the peripheral blood lymphocytes from patients with HN. METHODS Peripheral blood was obtained from patients with HN associated with benign pigmented lesions (5) or melanoma (2) as well as from patients with melanoma without HN (5) and healthy subjects (10). Activated lymphocytes were detected by flow cytometry analysis using monoclonal antibodies (mAb) against CD69, CD71, CD98, HLA-DR, and activated beta(1) integrins (HUTS-21 mAb). RESULTS The peripheral blood lymphocytes from patients with HN, associated with either benign or malignant lesions, exhibited a significantly higher expression of all activation markers studied compared with patients with melanoma without HN or compared with healthy subjects. Therefore the peripheral blood of HN patients contained a significant fraction of lymphocytes with an activated (CD69(+), HLA-DR(+), CD98(bright)), cell proliferating (CD71( bright)), and high adhesive (HUTS-21(bright)) phenotype. These activated cells disappeared from peripheral blood after the surgical resection of the skin lesion. CONCLUSION Our findings further support the involvement of immune activation in HN phenomenon.

Near‐visible light and UV photoprotection in the treatment of melasma: a double‐blind randomized trial

Melasma is an acquired hyperpigmentation on sun‐exposed areas. Multiple approaches are used to treat it, but all include broad ultraviolet (UV)‐spectrum sunscreens. Visible light (VL) can induce pigmentary changes similar to those caused by UV radiation on darker‐skinned patients.

α-Synuclein inclusions in the skin of Parkinson's disease and parkinsonism.

The presence in the brain of α‐synuclein containing Lewy neurites, or bodies, is the histological hallmark of Parkinsons disease (PD). The discovery of α‐synuclein aggregates in nerve endings of the heart, digestive tract, and skin has lent support to the concept of PD as a systemic disease. Our goals were, first, to demonstrate the presence of α‐synuclein inclusions in the skin and, second, to detect quantitative differences between patients with PD and atypical parkinsonism (AP).

Use of Raman spectroscopy for the early detection of filaggrin-related atopic dermatitis

Background: Filaggrin (FLG) gene mutations, which result in complete or incomplete loss of proFLG/FLG peptides, have been reported as an important predisposing factor for atopic dermatitis (AD) and secondary atopic phenotypes such as atopic asthma.

The effect of methotrexate on the expression of cell adhesion molecules and activation molecule CD69 in psoriasis.

Background  The mechanism of the action of methotrexate (MTX) in the treatment of psoriasis has not been completely elucidated.

Pentoxifylline in the Treatment of Actinic Prurigo

Background: Actinic prurigo (AP) is a chronic familial photodermatosis usually seen in Latin-American Mestizo and Indian populations. It frequently begins in childhood and is more prevalent in females. The pathogenesis of AP has not been clearly elucidated, but previous studies have suggested an immune-mediated condition. Many drugs have been employed to treat AP patients with variable success. Objective: To assess the clinical efficacy of pentoxifylline (PTX) in the treatment of AP patients by measuring its effects on lesions and pruritus. Methods: 10 patients with severe AP were included to receive PTX in a 6-month open-label uncontrolled study. Results: Clinical improvement of lesions was evident in all patients. Relief in pruritus was evident after 1 month of treatment and was maintained while receiving PTX. Five patients were followed up for 2 years, 2 obtained complete remission, and 3 had an important reduction in the use of corticosteroids. Conclusion: PTX was useful in the treatment of our actinic prurigo patients. It may induce a complete or partial remission of lesions and allow a decrease in the use of topical corticosteroids.

Molecular structure and concentration of melanin in the stratum corneum of patients with melasma.

Melasma is an abnormal acquired hyperpigmentation of the face of unknown origin, it is considered a single disease and very little has been found regarding its pathogenesis. It is usually assumed that melasma is due to excessive melanin production, but excessive retention or abnormal metabolism of this molecule has not yet been considered. In order to search for an alternate explanation for the excessive pigmentation in melasma the molecular structure and concentration of melanin in the stratum corneum of patients with melasma was analyzed using Raman spectroscopy and optical transmission spectroscopy, respectively. From this study it became apparent that in melasma melanin is concentrated in the deeper layers of the skin but its exteriorization remains the same as for healthy skin. Raman spectroscopy measurements showed degraded molecules of melanin in some subjects, which may help explain the variable success rate of the standard therapy.