The sticky platelet syndrome.

The sticky platelets syndrome (SPS) is a procoagulant condition based on either arterial, venous, or capillary thrombi caused by hyperesponsive and hyperaggregable platelets. This is a frequent disease, which often remains clinically inapparent, until stressful events or combination with other factors increase the risk of developing SPS. The condition is due to a congenital platelet defect with autosomal dominant characteristics, leading to the increased platelet aggregability when they are challenged with epinephrine and adenosine diphosphate. Nowadays classification of this disorder is based on platelet reactivity to both ADP and epinephrine (SPS type 1), epinephrine alone (SPS type 2), and ADP alone (SPS type 3). The diagnoses of the syndrome depend on the functional aggregometer assay. This condition should be taken into account whenever a patient with thrombophilia is considered.

Use of Raman spectroscopy in the analysis of nickel allergy.

Raman spectra of the skin of subjects with nickel allergy are analyzed and compared to the spectra of healthy subjects to detect possible biochemical differences in the structure of the skin that could help diagnose metal allergies in a noninvasive manner. Results show differences between the two groups of Raman spectra. These spectral differences can be classified using principal component analysis. Based on these findings, a novel computational technique to make a fast evaluation and classification of the Raman spectra of the skin is presented and proposed as a noninvasive technique for the detection of nickel allergy.

Poiquilodermatomiositis / No disponible

No disponible

Noninvasive estimation of chronological and photoinduced skin damage using Raman spectroscopy and principal component analysis.

BACKGROUND: Skin aging can be attributed to endogenous and exogenous factors which modify the hydration and protein structure of the skin which can be measured using Raman spectroscopy. METHOD: This study included 21 healthy adult volunteers, aged 32-81 years, Raman spectra were obtained from sun-protected and sun-exposed skin, also three millimeter punch biopsies of sun-exposed skin were collected and analyzed. The Raman spectra were analyzed using principal component analysis and the results were correlated with clinical and histological findings. RESULTS: The principal component analysis of the Raman spectra shows that the first principal component (PC1) obtained from the sun-protected skin is related to the age of the subject, which can be taken as a measure of chronological aging, the second (PC2) and fourth (PC4) principal components obtained from Raman spectra of sun-exposed skin are related to the amount of solar elastosis and collagen, respectively. CONCLUSION: In this work a relationship was found between histological properties of photoaged skin and noninvasive measurements based on Raman and principal components analysis (PCA). These relationships can be used to assess noninvasively the photoinduced damage and chronological characteristics of skin.

Noninvasive detection of filaggrin gene mutations using Raman spectroscopy.

Knowledge of the existence of filaggrin (FLG) gene mutations might be helpful for a subclassification of patients with atopic dermatitis (AD) which can be used to introduce individualized treatments. In this work the filaggrin content in the skin is assessed using Raman spectroscopy and the results are compared to FLG genotyping of Mexican-mestizo patients. Results showed that the 2282del4 and R501X mutations present in the European population but absent in people of Asian or African descent are also present in the Mexican-mestizo population. The results also showed that patients with filaggrin gene mutations presented lower filaggrin concentrations measured using the vector correlation of their skin Raman spectra and a fixed spectrum of pure human recombinant filaggrin, these results indicate that Raman spectroscopy may be used as a noninvasive tool to detect FLG gene mutations.

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.

[Assessment of moisturizing creams available in México]. / Evaluación de cremas humectantes disponibles en México.

UNLABELLED: There is a broad diversity of moisturizers for the treatment of dry skin; however, we do not know their real effectiveness. The objective here was to evaluate different products through their capacity to increase the epidermal hydration level (EHL) and to reduce the transepidermal water loss (TEWL). MATERIALS AND METHODS: We evaluated twenty moisturizers in sixteen individuals. The analysis was made on volar forearm and basal measurements were made for EHL and TWEL with the later application of 8 gm of each moisturizer on a 2 cm2 area. RESULTS: For the EHL we found significant differences among the products (p < 0.0001), but only 35% (n = 7) of the moisturizers registered ascending levels of hydration in the course of measurements. The variance analysis for TEWL also was significant (p < 0.0001). CONCLUSIONS: In the short term only a few products induced a significant change in EHL. This study demonstrates the necessity to obtain objective information in order to avoid false publicity claims that may erroneously influence our prescription habits.

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.

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.

[Ultraviolet absorption of prescription sunblocks in Mexico]. / Absorción ultravioleta de los protectores solares para prescripción en México.

BACKGROUND: An appropriate sunscreen should provide high and broad ultraviolet protection both for the B and A range. The objective was quantify the ultraviolet absorption spectrum in sunscreens available for medical prescription, and analyze its relationship with the labeled Sun Protection Factor (SPF). MATERIAL AND METHODS: Thirty-nine sunscreens were analyzed in vitro using ultraviolet spectroscopy following exposure to simulated solar irradiation. RESULTS: Fifty-six percent of sunscreens absorbed 90% or more of ultraviolet radiation. Seventy-five percent (n = 34) absorbed more than 95% of ultraviolet B radiation, and 46% (n = 18) more than 90% of ultraviolet A. There was no significant association between ultraviolet absorption and SPF. CONCLUSION: We were unable to estimate ultraviolet absorption only by its SPF. Protection differed considerably among products with similar SPF. Our study highlights regulation deficiencies in marketing practices of these products.

Absorción ultravioleta de los protectores solares para prescripción en México / Ultraviolet absorption of prescription sunblocks in Mexico

Antecedentes: Un fotoprotector adecuado debe proporcionar una elevada y amplia protección ultravioleta no sólo para el rango B sino también para el A. El objetivo fue cuantificar el espectro de absorción ultravioleta en protectores solares disponibles para prescripción médica, y analizar su relación con el factor de protección solar mostrado en su etiqueta. Material y métodos: Se analizaron 39 protectores solares posterior a exposición de radiación solar simulada y cuantificación de su espectro de absorbancia ultravioleta in vitro. Resultados: 56% de los productos absorbió 90% o más radiación ultravioleta; 75% (n=34) absorbió más de 95% de radiación ultravioleta B, y 46% (n=18) más de 90% de ultravioleta A. No existió relación significativa entre la absorción ultravioleta y el factor de protección solar. Conclusiones: En esta muestra, la cantidad de absorción ultravioleta no pudo estimarse únicamente por el factor de protección solar, y la protección ultravioleta A varía significativamente entre productos con el mismo factor de protección solar. Este estudio hace evidente las deficiencias en la regulación para la comercialización de estos productos.

BACKGROUND: An appropriate sunscreen should provide high and broad ultraviolet protection both for the B and A range. The objective was quantify the ultraviolet absorption spectrum in sunscreens available for medical prescription, and analyze its relationship with the labeled Sun Protection Factor (SPF). MATERIAL AND METHODS: Thirty-nine sunscreens were analyzed in vitro using ultraviolet spectroscopy following exposure to simulated solar irradiation. RESULTS: Fifty-six percent of sunscreens absorbed 90% or more of ultraviolet radiation. Seventy-five percent (n = 34) absorbed more than 95% of ultraviolet B radiation, and 46% (n = 18) more than 90% of ultraviolet A. There was no significant association between ultraviolet absorption and SPF. CONCLUSION: We were unable to estimate ultraviolet absorption only by its SPF. Protection differed considerably among products with similar SPF. Our study highlights regulation deficiencies in marketing practices of these products.

Conocimientos y actitudes de la población mexicana con respecto a la radiación solar / Knowledge and attitudes of Mexican population concerning solar radiation

Antecedentes. Los efectos de la radiación solar en la salud humana dependen del ambiente, costumbres y predisposición genética. Objetivo. Identificar el fenotipo, los hábitos, los conocimientos y las medidas preventivas con respecto a la exposición solar de la población local. Métodos. Se realizó una encuesta a la población mayor de 15 años en relación con su tiempo de exposición solar, las formas de protección empleadas y sus conocimientos generales sobre los efectos nocivos. Resultados. Se hicieron y analizaron 964 encuestas. El fototipo se distribuye entre población de piel blanca (7.4% de los encuestados), población de piel morena clara (24.8%) y de piel morena oscura (67.8%). La exposición solar en días laborables fue menor a 15 minutos por día en el 27.8% de los casos y mayor a 60 minutos en el 38.8%; no se observó variación significativa en estos porcentajes similares en fines de semana. En cuanto a la protección a al exposición solar, el 30% de nuestra población no se protege del sol, el 25.5% busca sombra, el 41% utiliza sombreros y el 11.8% usa protector solar. El 85.4% reconoce que la radiación solar causa cáncer cutáneo, el 64.1% que es fatal, el 83.4% que acelera el envejecimiento y sólo el 26.5% considera que el bronceado es saludable. Conclusión. A pesar de que la mayor parte de la población reconoce que el sol causa envejecimiento y cáncer cutáneo, su exposición solar es prolongada. Estos hallazgos pueden ser de utilidad para el diseño de campañas destinadas a educar a grupos vulnerables.

BACKGROUND: The effects of solar radiation in human health is dependent upon environment, behavior, and genetic characteristics. OBJECTIVE: Identify phenotypic features, attitudes, knowledge and preventive measures concerning sun exposure among a local population. METHODS: People older than 15 years were interviewed concerning time of sun exposure, photoprotection, and general knowledge about adverse effects of sun irradiation. RESULTS: 964 questionnaires were analyzed. White-skin population represented 7.4%, light-brown 24.8%, dark-brown 67.8%. Exposure time on working days was up to 15 min in 27.8%, and more than 60 min in 38.8%. On weekends, time exposure was similar. 30% did not take any preventive measures 41% wore hats and 11.8% used sunscreens. Among participants, 85.4% were aware that sun exposure caused skin cancer, 64. 1% knew that mortality is increased, 83.4% reported that excessive sun exposure is related to aging of the skin, and 26.5% believed tanning is healthy. CONCLUSIONS: In spite of thefact that a great majority of the population recognized that sun exposure produces aging and skin cancer, their exposure is widespread. This survey may be a valuable tool to design preventive public health campaigns that target high risk groups.