Formation of intraneuronal iron deposits following local release from nanostructured silica injected into rat brain parenchyma.

Nanostructured materials with controllable properties have been used to cage and release various types of compounds. In the present study, iron-loaded nanostructured sol-gel SiO2-Fe materials were prepared and injected into the rat brain to develop a method for gradual iron delivery into the neurons with the aims to avoid acute iron toxicity and develop an animal model of gradual, metal-induced neurodegeneration. Nanoparticles were prepared by the traditional method of hydrolysis and condensation reactions of tetraethyl orthosilicate at room temperature and subsequent heat treatment at 200 °C. FeSO4 was added in situ during the silica preparation. The resulting materials were characterized by UV-VIS and infrared spectroscopies, X-ray diffraction, and N2 adsorption-desorption. An in vitro ferrous sulfate release test was carried out in artificial cerebrospinal fluid as the release medium showing successful ferrous sulfate loading on nanostructured silica and sustained iron release during the test time of 10 h. Male Wistar rats administered with SiO2-Fe nanoparticles in the substantia nigra pars compacta (SNpc) showed significant intraneuronal increase of iron, in contrast to the animals administered with FeSO4 that showed severe neuronal loss, 72 h post-treatment. Both treatments induced lipid fluorescent product formation in the ventral midbrain, in contrast to iron-free SiO2 and PBS-only injection controls. Circling behavior was evaluated six days after the intranigral microinjection, considered as a behavioral end-point of brain damage. The apomorphine-induced ipsilateral turns in the treated animals presented significant differences in relation to the control groups, with FeSO4 administration leading to a dramatic phenotype, compared to a milder impact in SiO2-Fe administrated animals. Thus, the use of SiO2-Fe nanoparticles represents a slow iron release system useful to model the gradual iron-accumulation process observed in the SNpc of patients with idiopathic Parkinson's disease.

Localized standing waves induced by spatiotemporal forcing.

Particle-type solutions are observed in out-of-equilibrium systems. These states can be motionless, oscillatory, or propagative depending on the injection and dissipation of energy. We investigate a family of localized standing waves based on a liquid-crystal light valve with spatiotemporal modulated optical feedback. These states are nonlinear waves in which energy concentrates in a localized and oscillatory manner. The organization of the family of solutions is characterized as a function of the applied voltage. Close to the reorientation transition, an amplitude equation allows us to elucidate the origin of these localized states and establish their bifurcation diagram. Theoretical findings are in qualitative agreement with experimental observations. Our results open the possibility of manipulating localized states induced by light, which can be used to expand and improve the storage and manipulation of information.

Front propagation steered by a high-wavenumber modulation: Theory and experiments.

Homogeneously driven dynamical systems exhibit multistability. Depending on the initial conditions, fronts present a rich dynamical behavior between equilibria. Qualitatively, this phenomenology is persistent under spatially modulated forcing. However, the understanding of equilibria and front dynamics organization is not fully established. Here, we investigate these phenomena in the high-wavenumber limit. Based on a model that describes the reorientation transition of a liquid crystal light valve with spatially modulated optical forcing and the homogenization method, equilibria and fronts as a function of forcing parameters are studied. The forcing induces patterns coexisting with the uniform state in regions where the system without forcing is monostable. The front dynamics is characterized theoretically and numerically. Experimental results verify these phenomena and the law describing bistability, showing quite good agreement.

Transition to Spatiotemporal Intermittency and Defect Turbulence in Systems under Translational Coupling.

Out of equilibrium systems under the influence of enough energy injection exhibit complex spatiotemporal behaviors. Based on a liquid crystal light valve experiment with translational optical feedback, we observe propagation, spatiotemporal intermittency, and defect turbulence of striped waves. A prototype model of pattern formation with translational coupling shows the same phenomenology. Close to the spatial instability, a local amplitude equation is derived. This amplitude equation allows us to reveal the origin and bifurcation diagram of the observed complex spatiotemporal dynamics. Experimental observations have a qualitative agreement with theoretical findings.

Guía de recomendación ACCHED-SCHGE para el funcionamiento de las unidades de endoscopia durante el brote de coronavirus (COVID-19) / Guideline recommendations ACHED-SCHGE for the endoscopy units during the Coronavirus outbreak (COVID-19)

The outbreak of COVID-19 disease has recently spread from its original place in Wuhan, Hubei province, China, to the entire world, and has been declared to be a pandemic by the World Health Organization in March 2020. All countries in America, in particular Chile, show an important increase in COVID-19 cases and deaths. The clinical manifestations of COVID-19 are a broad spectrum, from asymptomatic mild disease, to severe respiratory failure, shock, multiorgan dysfunction and death. Thus, high clinical suspicion and appropriate structure risk stratification are needed. Health care teams in endoscopy units, are at an increased risk of infection by COVID-19 from inhalation of droplets, mucosae contact, probably contamination due to contact with stools. Endoscopic aerosolized associated infections have also been reported. Different societies' recommendations, have recently placed digestive endoscopy (especially upper) among the high risk aerosol generating procedures (AGPs). In addition, live virus has been found in patient stools. On top of this, the infected health professionals may transmit the infection to their patients. Health care infection prevention and control (HCIPC), has been shown to be effective in assuring the safety of both health care personnel and patients. This is not limited to the correct use of personal protective equipment (PPE), but is based on a clear, detailed and well communicated HCIPC strategy, risk stratification, use of PPE, and careful interventions in patients with moderate and high risk of COVID-19. A conscientious approach regarding limited resources is important, as the simultaneous outbreak in all countries heavily affects the availability of health supplies. The Chilean Gastroenterology Society (SChGE) and Digestive Endoscopy Association of Chile (ACHED) are joining to provide continued updated guidance in order to assure the highest level of protection against COVID-19, for both patients and health care workers. This guideline will be updated online as needed.

El brote de la enfermedad denominada COVID-19, se ha extendido desde su origen en Wuhan, provincia de Hubei, China, a todo el mundo. La Organización Mundial de la Salud lo declaró pandemia en marzo de 2020. Todos los países de América, en especial Chile, presentan incremento de casos y fallecidos. Las manifestaciones clínicas de COVID-19 van desde una enfermedad leve, hasta insuficiencia respiratoria severa, shock, disfunción orgánica y muerte. Se necesita una alta sospecha clínica y una adecuada estratificación del riesgo. El equipo de salud en las unidades de endoscopia, tiene un mayor riesgo de COVID-19 que otras unidades clínicas y de apoyo diagnóstico, dada la mayor exposición a inhalación de gotas, contacto posible con mucosas y contaminación por contacto con deposiciones. Recomendaciones de diferentes sociedades colocan la endoscopia digestiva (especialmente la esofagogastroscopia o endoscopia digestiva alta, EDA) entre los procedimientos generadores de aerosoles (PGA) de alto riesgo. Además, se han encontrado virus viables en las deposiciones de los pacientes. Potencialmente, los profesionales de la salud infectados podrían contagiar a los pacientes. Se ha demostrado que la prevención y control de infecciones asociadas a la atención de salud (IAAS), son efectivos para garantizar la seguridad tanto del personal de salud, como de los pacientes. Esto no es solamente el correcto uso del equipo de protección personal (EPP), sino que se basa en una clara estrategia de IAAS, bien comunicada, con estratificación de riesgo, uso de EPP e intervenciones correctas en pacientes con riesgo moderado y alto. Es relevante un enfoque sobre los limitados recursos, dado la simultaneidad del brote en todos los países, que afecta la disponibilidad de insumos. La Sociedad Chilena de Gastroenterología (SChGE) y la Asociación Chilena de Endoscopia Digestiva (ACHED) publican esta guía actualizada para apoyar las buenas prácticas contra COVID-19, tanto para pacientes como para el equipo de salud. Esta guía podrá tener actualizaciones según avance la información disponible.

Population data for 21 autosomal STR loci (GlobalFiler kit) in two Mexican-Mestizo population from the northwest, Mexico.

Mexican Mestizos (admixed) have been poorly studied for short tandem repeats (STRs) included for new human identification (HID) kits, such as the GlobalFiler PCR Amplification kit. Therefore, this kit was analyzed in 784 unrelated volunteers from the city of Tijuana (n = 381) and Sonora state (n = 403) in the northwest region of Mexico. Allele frequencies, forensic parameters, Hardy-Weinberg equilibrium, and linkage equilibrium were estimated or evaluated for 21 autosomal STRs, respectively. For this HID kit, the combined power of discrimination (PD) was > 0.99999999999999 (RMP range = 1.23 to 3.0 × 10-25), and the combined power of exclusion (PE) were 0.999999993 and 0.999999997 in Tijuana city and Sonora state, respectively. Interpopulation analyses based on STRs of the GlobalFiler kit was performed, including four Mexican Native American, one Mexican Mestizo, and four ethnic American populations (USA), previously studied. The low-but significant-differentiation observed among Mexican Mestizos (FST = 0.0969%; p = 0.02584) justifies the creation of STR databases for HID purposes in this country. In brief, results allow the confident use of the GlobalFiler kit for HID purposes in Mestizo population from the Northwest region Mexico.

Dissipative structures induced by photoisomerization in a dye-doped nematic liquid crystal layer.

Order-disorder phase transitions driven by temperature or light in soft matter materials exhibit complex dissipative structures. Here, we investigate the spatio-temporal phenomena induced by light in a dye-doped nematic liquid crystal layer. Experimentally, for planar anchoring of the nematic layer and high enough input power, photoisomerization processes induce a nematic-isotropic phase transition mediated by interface propagation between the two phases. In the case of a twisted nematic layer and for intermediate input power, the light induces a spatially modulated phase, which exhibits stripe patterns. The pattern originates as an instability mediated by interface propagation between the modulated and the homogeneous nematic states. Theoretically, the phase transition, emergence of stripe patterns and front dynamics are described on the basis of a proposed model for the dopant concentration coupled with the nematic order parameter. Numerical simulations show quite a fair agreement with the experimental observations.This article is part of the theme issue 'Dissipative structures in matter out of equilibrium: from chemistry, photonics and biology (part 2)'.

Correspondence between the CYP2C19 and CYP3A4 genotypes with the inferred metabolizer phenotype by omeprazole administration in Mexican healthy children.

WHAT IS KNOWN AND OBJECTIVE: CYP2C19 genotypes presumably allow the prediction of the metabolizer phenotypes: poor (PMs), extensive (EMs) and ultra-rapid (UMs). However, evidence from previous studies regarding this predictive power is unclear, which is important because the benefits expected by healthcare institutions and patients are based on this premise. Therefore, we aimed to complete a formal evaluation of the diagnostic value of CYP2C19 and CYP3A4 genes for predicting metabolizer phenotypes established by omeprazole (OME) administration in 118 healthy children from Jalisco (western Mexico). METHODS: The genotypes for CYP3A4*1B and CYP2C19*2, *3, *4, *5 and *17 alleles were determined. CYP2C19 and CYP3A4 phenotypes were obtained after 20 mg OME administration and HPLC quantification in plasma to estimate the Hydroxylation Index (HI = OME/HOME) and Sulfonation Index (SI = OME/SOME), respectively. RESULTS AND DISCUSSION: The distribution of genotypes and phenotypes for CYP2C19 and CYP3A4 was similar to previous studies in Mexico and Latin America. We estimated the CYP2C19 UM, EM and PM phenotype frequency in 0.84%, 96.61% and 2.54%, respectively. Although differences in the HI distribution were observed between CYP2C19 genotypes, they showed a poor diagnostic ability to predict the CYP2C19 metabolizer phenotype. Similarly, the number of CYP2C19 and CYP3A4 functional alleles was correlated with the HI distribution, but also their diagnostic ability to predict the CYP2C19 phenotype was poor. WHAT IS NEW AND CONCLUSION: The CYP2C19 phenotype is not predicted by the number of functional alleles of CYP2C19 and CYP3A4 genes. Phenotyping is still the most valuable alternative to dose individualization for CYP2C19 substrate drugs.

Forensic parameters and admixture in Mestizos from five geographic regions of Mexico based on 20 autosomal STRs (Powerplex 21 system).

We analyzed Mestizo (admixed) population samples from different geographic regions of Mexico (n = 1283) with 20 autosomal STRs (PowerPlex® 21, Promega Corp.). Allele frequencies and forensic parameters from the Northwest, Northeast, West, Center, and Southeast regions are reported, as well as from the pooled Mexican population sample. The combined PD and PE for this 20 STR system were > 0.9999999999 and > 0.99999996593% in all five population samples, respectively. Analysis of molecular variance (AMOVA) of these Mexican population samples, plus Monterrey (Northeast) and Mexico (Center) Cities, showed low but significant differences among Mexican-Mestizos from the seven populations (Fst = 0.20%; p = 0.0000). Structure analysis showed the highest proportion of Native American ancestry in Mexico City, Center, and Southeast regions, respectively, which was in agreement with the estimated genetic distances represented in a MDS plot and a NJ tree. The best fit of population clusters (K = 4) obtained with the Structure software indicates that Mexican-Mestizos are mainly composed by European, African, and two Native American ancestries. The European and Native American ancestries displayed a contrary gradient, increasing toward the North-West and South-Southeast, respectively. These 20 autosomal STR loci improved the admixture estimation regarding previous studies with the 13 CODIS-STRs, as supported by the higher similarity with previous estimates based on genome-wide SNP. In brief, this study validates the confident use of the PowerPlex® 21 system for human identification purposes in Mestizo populations throughout the Mexican territory.

Forensic parameters of the X-STR Decaplex system in Mexican populations.

We studied the X-STR decaplex system in 529 DNA female samples of Mexican populations from five geographic regions. Allele frequencies and forensic parameters were estimated in each region and in the pooled Mexican population. Genotype distribution by locus was in agreement with Hardy-Weinberg expectations in each Mexican population sample. Similarly, linkage equilibrium was demonstrated between pair of loci. Pairwise comparisons and genetic distances between Mexican, Iberoamerican and one African populations were estimated and graphically represented. Interestingly, a non-significant interpopulation differentiation was detected (Fst = 0.0021; p = .74389), which allows using a global Mexican database for forensic interpretation of X-STR genotypes.

Enfermedad de Grover, una patología ampollar poco frecuente: a propósito de 2 casos / Grover's disease, a pathology blistering unusual: About 2 cases

Grover's disease (GD) or transient acantholytic dermatosis, is a papulovesicular pruritic disease of unknown etiology. It´s most important histopathological finding is the presence of focal acantholysis. The incidence has not been firmly established. Case report: We report two cases of papulovesicular rashes, the first one in a 79 year old man with good response to second line treatment and the second one, in a 30 year old woman. Both with different suspected triggering factors. Comment: GD predominates in white men with an average age of presentation of 61. Clinically, it presents as erythematous papules, crusted-papule and is usually pruritic. The etiopathology is still unknown, but it is associated with triggers such as: ultraviolet radiation (UVR), ionizing radiation, heat, sweat, friction and chemotherapy. Acantholysis is the classic histological finding. Management includes general measures, topical corticosteroids, calcineurin inhibitors, tretinoin, calcipotriene and antihistamines. In refractory cases, second-line treatment is used: oral isotretinoin, systemic corticosteroids and phototherapy. Paradoxically, phototherapy can also trigger GD. Conclusions: Due to the low prevalence of GD in Chile, 2 new cases are provided to the literature. In both cases, the diagnostic presumption was based on an exhaustive clinical history, confirmed by histopathological findings. (AU)

Forensic efficiency parameters of the Investigator Argus X-12 kit in women from two Mestizo and seven Amerindian populations from Mexico.

Allele frequency distribution and statistical parameters of forensic efficiency concerning the Investigator Argus X-12 kit (Qiagen, Hilden, Germany) were determined in a total sample of 641 unrelated Mexican females, including two Mestizo-admixed- populations (n=309) and seven Amerindian groups (n=332) from the main regions of the country. Most of the 12 X-STRs were in agreement with Hardy-Weinberg expectations in all nine Mexican populations. The power of discrimination in females (PD) and Median exclusion chance for trios (MECT) and duos (MECD) of this genetic system based on X-STRs were >99.99%. Although Mexican populations showed significant pairwise differentiation, a closer relationship was evident between Amerindian groups and nearby Mestizos, in agreement with historical records, previous genetic studies, and X-linked inheritance pattern expectations.

Nonvariational mechanism of front propagation: Theory and experiments.

Multistable systems exhibit a rich front dynamics between equilibria. In one-dimensional scalar gradient systems, the spread of the fronts is proportional to the energy difference between equilibria. Fronts spreading proportionally to the energetic difference between equilibria is a characteristic of one-dimensional scalar gradient systems. Based on a simple nonvariational bistable model, we show analytically and numerically that the direction and speed of front propagation is led by nonvariational dynamics. We provide experimental evidence of nonvariational front propagation between different molecular orientations in a quasi-one-dimensional liquid-crystal light valve subjected to optical feedback. Free diffraction length allows us to control the variational or nonvariational nature of this system. Numerical simulations of the phenomenological model have quite good agreement with experimental observations.

¿Por qué no diagnosticamos el cáncer gástrico incipiente? ¿Cómo podemos mejorar? / Why do we fail in the diagnosis of early gastric cancer? How can we improve?

Detection and treatment of gastric cancer (GC) in early stages is the most effective approach for improving prognosis. Patients with early gastric cancer (EGC), defined as a type of cancer affecting only mucosa and submucosa, has a good prognosis in the long-term, and if some criteria are met, endoscopic therapy is curative. Unfortunately EGC diagnosis is rare, except in case of some Asian countries, where more than 50% of tumors are diagnosed in this stage. In Japan, the main technique for early diagnosis is opportunistic screening, i.e. endoscopy performed for different reasons. Some of the factors that affect endoscopic diagnose include: characteristics of the lesion (some cases slight changes in color or in the surface, a location that is difficult to detect, except in retro view); elements associated with the endoscopic technique (lesions hidden underneath gastric contents, non-systematic visualization, not enough time for exploration); and early access to the procedure (long waiting lists, lack of clinic or epidemiology screening criteria, lack of risk-stratification looking for pre-malignant lesions to establish endoscopic follow-up). Know and act upon the mentioned factors is a path that has proven to improve EGC diagnosis and therefore, improve prognosis.

Detectar y tratar el cáncer gástrico (CG) en una etapa inicial constituye la estrategia más efectiva para mejorar el pronóstico de esta patología. Pacientes con CG incipiente (CGI), definido como el que compromete sólo la mucosa y la submucosa, tienen un muy buen pronóstico a largo plazo y si se cumplen algunos criterios, el tratamiento endoscópico es curativo. Desgraciadamente el diagnóstico de CGI es infrecuente en todo el mundo, a excepción de algunos países asiáticos donde más de la mitad de los tumores se diagnostican en esta etapa. En Japón la principal vía por la que se realiza este diagnóstico precoz es mediante el tamizaje oportunista, es decir, la endoscopia que se realiza de manera cotidiana por diferentes motivos. Dentro de los factores que afectan la capacidad diagnóstica de la endoscopia destacan: las características de la lesión (algunos casos con discretos cambios de color o superficie, ubicación habitualmente en áreas de mejor visualización en retrovisión); factores asociados a la técnica endoscópica (contenido gástrico que puede ocultar lesiones, visualización no sistemática, tiempo insuficiente de exploración); y el acceso oportuno a ella (largas listas de espera, falta de criterios de selección clínicos o epidemiológicos, falta de estratificación del riesgo mediante la búsqueda de lesiones premalignas para definir intervalos de seguimiento endoscópico). Conocer y actuar sobre los factores descritos es un camino que ha demostrado su utilidad en mejorar el diagnóstico del CGI y así mejorar su pronóstico.

Population data of 23 STR loci (PowerPlex® Fusion System) in Mexican Mestizos from the West Region.

We analyzed 238 unrelated Mestizo (admixed) individuals from the West region of Mexico with the PowerPlex® Fusion System (Promega Corp.). Allele frequencies and forensic parameters were estimated for the 23 STRs included in this kit. Hardy-Weinberg equilibrium by locus and non-association between pair of loci were demonstrated by exact tests in this population. The combined PE and PD offered by this HID kit were ≥0.9999999986, representing a substantial improvement with respect to those previously offered by 15 STR systems. Interpopulation comparison by AMOVA tests demonstrated low but significant differences among Mexican Mestizos from West, Center, and Northeast regions (Fst = 0.01558; p = 0.0000), similar to the observed among three main ethnic groups from USA (Fst = 0.02048; p = 0.0000). This finding is consistent with the contrary clines of European and Amerindian ancestries described throughout the Mexican territory for Mestizos, the largest population (~90 %) in this country.

Forensic parameters of the Investigator DIPplex kit (Qiagen) in six Mexican populations.

Allele frequencies and statistical parameters of forensic efficiency for 30 deletion-insertion polymorphisms (DIPs) were estimated in six Mexican populations. For this purpose, 421 unrelated individuals were analyzed with the Investigator DIPplex kit. The Hardy-Weinberg and linkage equilibrium was demonstrated for this 30-plex system in all six populations. We estimated the combined power of discrimination (PD ≥ 99.999999%) and combined power of exclusion (PE ≥ 98.632705%) for this genetic system. A low but significant genetic structure was demonstrated among these six populations by pairwise comparisons and AMOVA (F ST ≥ 0.7054; p ≤ 0.0007), which allows clustering populations in agreement with geographical criteria: Northwest, Center, and Southeast.

Validez y confiabilidad de una escala de clasificación de limpieza gástrica en endoscopia digestiva alta en población chilena / Validity and reliability of a gastric cleansing scale in upper endoscopyin chilean population

The presence of foam and bubbles during upper gastrointestinal endoscopy (UGE) obscures the view of gastric lesions. Objective: To assess the confidence of a gastric cleansing scale in UGE. Methods: Prospective, multicenter study. The instrument was administered to patients undergoing a UGE examination. For the gastric visualization scale, the stomach was divided in 4 parts and a 1-4 scale was used to classify each part, with a total score of 4 (optimal view of gastric mucosa) and 16 (poor view of gastric mucosa), assessed by 2 independent endoscopists. An initial cleansing score was obtained and later, after cleansing of each studied section, and total. Inter-observer concordance was established by means of Kappa test, and the agreement on the global cleansing score was established with the Bland-Altman plot. Results: 53 patients went under UGE, with an average age of 48,7 years and 62,3 percent female subjects. The main indication for performing the UGE examination was gastroesophageal reflux disease (GERD) (32.1 percent). Average duration of the procedure was 13.6 minutes. The average total gastrointestinal view before cleansing with water was 6.26 points (scale from 4 to 16) and 5.1 points (p < 0.001) after cleansing. 37.7 percent required at least 50 cc of water for cleansing. The difference in the pre and post cleansing score inter-observers was no different of 0. Kappa value obtained in gastric fundus, upper body, lower body and antrum before cleansing was 0.81; 0.71; 0.9 and 0.8, respectively. Kappa value obtained after cleansing of gastric fundus, upper body, lower body and antrum was 0.84; 0.65; 0.81 and 0.78; respectively. The mean difference between inter-observer scores before cleansing was 0.08 (p = 0.51), and after cleansing, 0.02 (p = 0.78)...

La presencia de espuma y burbujas durante la endoscopia digestiva alta (EDA) es una limitante para la visualización de lesiones gástricas. Objetivo: Evaluar la confiabilidad de una escala de clasificación de limpieza gástrica en EDA. Métodos: Estudio prospectivo, multicéntrico. Se aplicó el instrumento a pacientes que estaban agendados para EDA. Para la clasificación de visualización gástrica, el estómago se dividió en 4 porciones y se utilizó una escala de 1 a 4 por porción, sumando un puntaje total entre 4 (óptima visualización de la mucosa) y 16 (pobre visualización de ésta), evaluada por 2 endoscopistas independientes. Se obtuvo un puntaje de limpieza inicial y luego de la limpieza con agua de cada segmento estudiado y total. La concordancia inter-observador se estableció por medio del test de Kappa y el acuerdo para el puntaje global de limpieza fue establecido mediante el gráfico de Bland-Altman. Resultados: 53 pacientes fueron sometidos a EDA, con edad promedio de 48,7 años y 62,3 por ciento de sexo femenino. La principal indicación de EDA fue enfermedad por reflujo gastroesofágico (32,1 por ciento). El tiempo promedio del procedimiento fue 13,6 min. El promedio de visualización gástrica total previo a limpieza con agua fue de 6,26 puntos (escala 4 a 16) y post limpieza 5,1 puntos (p < 0,001). Para la limpieza el 37,7 por ciento requirió al menos 50 cc de agua. La diferencia de puntaje de visualización pre y post limpieza inter observador no fue distinta de 0. En fondo gástrico, cuerpo alto, cuerpo bajo y antro se obtuvo un valor de Kappa previo a limpieza de 0,81; 0,71; 0,9 y 0,8, respectivamente. El valor de Kappa posterior a limpieza en fondo gástrico, cuerpo alto, cuerpo bajo y antro fue 0,84; 0,65; 0,81 y 0,78, respectivamente. La diferencia media de los puntajes inter-observadores previos a la limpieza gástrica fue de 0,08 (p = 0,51) y posterior a la limpieza gástrica fue de 0,02 (p = 0,78)...

[Aetiology of childhood alopecia]. / Caracterización de las causas de alopecia infantil.

INTRODUCTION: Childhood alopecia is a relative rare event in general paediatric dermatology practice. Hair loss in children may have multiple causes, and there are different types of alopecia according to age groups. The aim of the study was to describe the clinical and epidemiological profile of alopecia in children from two Chilean paediatric hospitals. PATIENTS AND METHOD: Descriptive analysis of clinical records of patients from the Dermatology Department of Roberto del Rio and Luis Calvo Mackenna Hospitals between January 2007 and June 2010. Patients with clinical diagnosis of alopecia were included. RESULTS: A total of 345 clinical records were analysed, with 179 males (51.9%). The median age was 72 months. Overall, the most common diagnoses were: alopecia areata (AA), (36.8%), tinea capitis (TC), (21%), nevus sebaceous (13.2%), and tellogen effluvium (8.7%). According to age groups, in newborns, the most common causes were aplasia cutis and nevus sebaceous. In toddlers, pre-school and school children, the principal causes were nevus sebaceous, AA and TC. Trichotillomania was also significant in school children. In adolescents, nevus sebaceous, AA and tellogen effluvium were the most frequent diagnoses. AA was statistically associated with autoimmune disease, thyroid disease, nail disorder, psychiatric disease, and Down's syndrome. The most common aetiological agent in TC was M. canis (86.6%). Trichotillomania was also statistically associated to psychiatric disorders. CONCLUSIONS: In this study, the main causes of alopecia in children were acquired and non-scarring alopecia. In our results, the type of alopecia varies according to age group. Some types of childhood alopecia showed a close correlation to psychiatric disorders.