Frequency of autoantibodies and symptoms suggestive of gastrointestinal disease in a group of patients with psoriasis / Frecuencia de autoanticuerpos y síntomas sugestivos de enfermedad gastrointestinal en un grupo de pacientes con psoriasis

ABSTRACT Introduction: Psoriasis is a chronic disease associated with multiple comorbidities including inflammatory intestinal disease. There are no previous studies in Colombia regarding the relationship of gastrointestinal symptoms in patients with psoriasis. Objective: To determine the frequency of symptoms and autoantibodies suggestive of gastrointestinal disease in patients with psoriasis, and to compare the results with healthy controls, as well as their relationship with disease activity. Materials and methods: Cross-sectional study with an analytical component, including a questionnaire on symptoms and serum analysis of antibodies suggestive of gastrointestinal disease in cases and controls. Results: The analysis included 84 individuals, separated into groups of 44 cases and 40 controls. Mild psoriasis was observed in 64% of cases, and the remaining 36% had moderate to severe psoriasis. Topical treatments were given to 71% of cases, with another 16% using oral treatments, and 14% received biological treatment. The main symptoms of gastrointestinal disease were, abdominal distention (45%), constipation (39%), and fatigue (34%). A comparison showed a higher prevalence of gastrointestinal symptoms in cases vs. controls, and fatigue was statistically significant (p = 0.04). Only the antinuclear autoantibodies in the serum analysis were statistically significant (0 vs. 43%; p = 0.01). Conclusions: The prevalence of symptoms and autoantibodies suggestive of gastrointestinal disease in patients with psoriasis is considered important, even although there are no significant differences when compared with healthy controls. Some patients with gastrointestinal symptoms had positive autoantibodies. This suggests that an adequate clinical follow-up should be carried out. Dermatologists have a decisive role in the integral management of patients.

RESUMEN Introducción: La psoriasis es una enfermedad crónica asociada con múltiples comorbilidades, incluida la enfermedad inflamatoria intestinal. Sin embargo, no existen estudios previos en Colombia sobre la relación de los síntomas gastrointestinales en pacientes con psoriasis. Objetivos: Se determinó la frecuencia de síntomas sugestivos de enfermedad gastrointestinal y autoanticuerpos asociados en pacientes con psoriasis, y su relación con la actividad de la misma. Además, se comparó con controles sanos. Materiales y métodos: Estudio transversal con componente analítico que incluyó una encuesta de síntomas y el análisis sérico de autoanticuerpos sugestivos de enfermedad gastrointestinal en casos y controles. Resultados: Ochenta y cuatro individuos analizados, distribuidos en 44 casos y 40 controles. El 64% de los casos tenían psoriasis leve y el 36% presentó psoriasis moderada a severa. El 71, el 16 y el 14% fueron tratados con tratamientos tópicos, orales y biológicos, respectivamente. Los principales síntomas gastrointestinales fueron distensión abdominal (45%), estreñimiento (39%) y fatiga (34%). La comparación arrojó una mayor prevalencia de síntomas gastrointestinales en los casos, y la variable fatiga fue estadísticamente significativa (p: 0,04). Solo el perfil de autoanticuerpos antinucleares fue estadísticamente significativo (0 vs. 43%; p: 0,001). No se encontró asociación con actividad de la enfermedad. Conclusiones: La prevalencia de síntomas y autoanticuerpos sugestivos de enfermedad gastrointestinal en pacientes se considera importante, a pesar de no mostrar diferencias significativas con los controles. Algunos pacientes con síntomas gastrointestinales mostraron autoanticuerpos positivos. Esto sugiere la necesidad de un seguimiento clínico adecuado. El dermatólogo tiene un papel decisivo en el manejo integral de los pacientes.

Physicochemical and antioxidant capacity analysis of colored sweet potato genotypes: in natura and thermally processed / Análises físico-químicas e capacidade antioxidante de genótipos coloridos de batata-doce in natura e termicamente processados

ABSTRACT: Sweet potato ( Ipomoea batatas (L.) Lam) is one of the most popular and ancient roots of Brazil and it can be consumed at different forms such as boiled, roasted or as sweets. Its cooking can lead to physicochemical transformations altering the nutritional properties. The objective of this study was to evaluate the physicochemical characteristics, bioactive compounds and antioxidant capacity of twelve sweet potato genotypes of varying pulp color in natura and roasted. Soluble solids, acidity, sugars, carotenoids, anthocyanins, phenolic compounds and antioxidant capacity were analyzed in the following sweet potatoes genotypes: cream pulp (Rubissol, Cuia, ILS03, ILS10, ILS12, ILS24 and ILS44); orange pulp (Amelia and Beauregard); and purple pulp (ILS56, ILS16 and ILS71). According to the results, it was observed a wide variation among the sweet potato genotypes for all analyzed parameters, in both preparation forms. The antioxidant capacity was a parameter with wide variation among genotypes, 210.29 to 7870.57µg trolox equivalent/g in in natura form and 673.26 to 17306.22µg trolox equivalent/g in roasted form. Soluble solids, acidity, sugars and bioactive compounds, with the exception of carotenoids, tended to be concentrated, also increases the total antioxidant capacity, in roasted sweet potatoes. In conclusion, genotype and the color of sweet potatoes were parameters that had an influence on its chemical composition. Cultivars such as Amelia and Beauregard stood out by the amounts of total soluble solids and carotenoids, respectively. The selections ILS 16 and ILS 56 are recommended as sources of anthocyanins. Thermal process influenced the concentration of antioxidant compounds and changed some physicochemical characteristics.

RESUMO: A batata-doce ( Ipomoea batatas (L.) Lam) é uma das raízes mais populares e antigas do Brasil, podendo ser consumida cozida, assada ou na forma de doces. A sua cocção pode levar à transformações físico-químicas alterando as propriedades nutricionais. O objetivo deste trabalho foi avaliar as características físico-químicas, compostos bioativos e atividade antioxidante de doze genótipos de batata-doce, de coloração de polpa variada, na forma in natura e assada. Foram determinados sólidos solúveis totais, acidez, açúcares, carotenoides, antocianinas, compostos fenólicos e atividade antioxidante nos seguintes genótipos de batatas-doces: polpa creme (Rubissol, Cuia, ILS03, ILS10, ILS12, ILS24 e ILS44); polpa laranja (Amélia e Beauregard) e polpa roxa (ILS56, ILS16 e ILS71). Quanto aos resultados foi observada ampla variação entre os genótipos de batata-doce, para todos os parâmetros analisados, em ambas as formas de preparo. A atividade antioxidante foi um parâmetro que demonstrou grande variação entre os genótipos, de 210,29 a 7870,57µg de equivalente trolox/g nos genótipos in natura e de 673,26 a 17306,22µg de equivalente trolox/g nos genótipos assados. Foi observado que em batatas-doces assadas os sólidos solúveis, acidez, açúcares e os compostos bioativos, com exceção dos carotenoides, tenderam a ser concentrados, elevando também a atividade antioxidante total. Em conclusão, o genótipo e a coloração da batata-doce foram parâmetros que exerceram influência sob a sua composição química. Cultivares como Amélia e Beauregard se destacaram pela quantidade de sólidos solúveis totais e carotenoides, respectivamente. Como fonte de antocianinas, as seleções ILS 16 e ILS 56 são recomendadas. O processo térmico influenciou a concentração de compostos antioxidantes e alterou algumas características físico-químicas.

Pitted keratolysis

Abstract Pitted keratolysis is a skin disorder that affects the stratum corneum of the plantar surface and is caused by Gram-positive bacteria. A 30-year-old male presented with small punched-out lesions on the plantar surface. A superficial shaving was carried out for scanning electron microscopy. Hypokeratosis was noted on the plantar skin and in the acrosyringium, where the normal elimination of corneocytes was not seen. At higher magnification (x 3,500) bacteria were easily found on the surface and the described transversal bacterial septation was observed.

Scanning electron microscopy of superficial white onychomycosis

AbstractSuperficial white onychomycosis is characterized by opaque, friable, whitish superficial spots on the nail plate. We examined an affected halux nail of a 20-year-old male patient with scanning electron microscopy. The mycological examination isolated Trichophyton mentagrophytes. Abundant hyphae with the formation of arthrospores were found on the nail's surface, forming small fungal colonies. These findings showed the great capacity for dissemination of this form of onychomycosis.

Scanning electron microscopy of the collodion membrane from a self-healing collodion baby

AbstractSelf-healing collodion baby is a well-established subtype of this condition. We examined a male newborn, who was covered by a collodion membrane. The shed membrane was examined with scanning electron microscopy. The outer surface showed a very compact keratin without the normal elimination of corneocytes. The lateral view of the specimen revealed a very thick, horny layer. The inner surface showed the structure of lower corneocytes with polygonal contour. With higher magnifications villous projections were seen in the cell membrane.

Un caso de apliaación de la dermatología integral / A case of applcaation of integral dermatology / Um caso de aplicação da dermatologia ittegral

La sarcoidosis es una enfermedad granulomatosa multisistémica de etiología desconocida. Presentamos el caso de una mujer que consulta por la preocupación estética de una lesión en dorso nasal. La exploración clínica lleva a sospechar de una enfermedad granulomatosa, por lo cual se lleva a biopsia y confirmación de su patología. La sarcoidosis es un trastorno crónico, que afecta múltiples órganos, su incidencia es variable, pero es mayor en países industrializados y se presenta en su mayoría en mujeres entre 20 y 40 años de edad. De las manifestaciones sistémicas, la más frecuente es la pulmonar, mientras que la afectación cutánea oscila entre 20-35%. El diagnóstico se establece con los hallazgos clínico-radiológicos apoyados por la evidencia histopatológica de granulomas no caseificantes, aunque estos últimos no son específicos, por lo que deben excluirse otros procesos.

Sarcoidosis is a multifactorial granulomatous disease of unknown etiology. We present a case of a woman who presents with cosmetic concerns of a lesion on the dorsum of the nose. The clinical exploration raises suspicion of granulomatous disease, reason for which reason a biopsy is done confirming her pathology. Sarcoidosis is a chronic disorder that affects multiple organs. Its incidence is unknown but is more frequent in industrialized countries, and majorly affects women between 20-40 years of age. Among its multiple manifestations, pulmonary symptoms are the most frequent, meanwhile the cutaneous manifestations are only present in 20-35% of the cases. The diagnosis is made by clinical-radiographic findings associated to histopathological findings of noncaseating granulomas, even though these are not specific to the disease and other processes must be ruled out.

A sarcoidose é uma doença granulomatosa multisistêmica de etiologia desconhecida. Apresentamos o caso de uma mulher que consulta pela preocupação estética de uma lesão em dorso nasal. A exploração clínica leva a suspeitar de uma doença granulomatosa, pelo qual se leva a biopsia e confirmação de sua patologia. A sarcoidoseé um transtorno crônico, que afeta múltiplos órgãos. A sua incidênciaé variável, mas é maior em países industrializados e tempredileção porque apresenta em sua maioria nas mulheres entre 20 e 40 anos de idade. Das manifestações sistêmicas, a mais frequente é a pulmonar, por enquanto que a afetação cutânea oscila entre 20-35%. O diagnóstico se estabelece com as descobertas clínico-radiológicas apoiadas pela evidência histopatológica de granulomas não caseificantes, porémestes últimos não são específicos, pelo que devem se excluir outros processos.

Scanning electron microscopy of molluscum contagiosum* / Microscopia eletrônica de varredura do molusco contagioso

Molluscum contagiosum is a disease caused by a poxvirus. It is more prevalent in children up to 5 years of age. There is a second peak of incidence in young adults. In order to examine its ultrastructure, three lesions were curetted without disruption, cut transversely with a scalpel, and routinely processed for scanning electron microscopy (SEM). The oval structure of molluscum contagiosum could be easily identified. In its core, there was a central umbilication and just below this depression, there was a keratinized tunnel. Under higher magnification, a proliferation similar to the epidermis was seen. Moreover, there were areas of cells disposed like a mosaic. Under higher magnification, rounded structures measuring 0.4 micron could be observed at the end of the keratinized tunnel and on the surface of the lesion.

Molusco contagioso é uma dermatovirose causada por um poxvírus, sendo mais prevalente em crianças com até 5 anos de idade. Um segundo pico de incidência é encontrado em adultos jovens. Com o objetivo de demonstrar sua ultraestrutura três lesões foram curetadas sem rompê-las, cortadas transversalmente e processadas de rotina para microscopia eletrônica de varredura. A estrutura oval do Molusco contagioso pôde ser facilmente observada, no seu centro há uma umbilicação central e logo abaixo observa-se um túnel queratinizado. Com aumentos progressivos observam-se proliferações semelhantes à epiderme e áreas de células dispostas em mosaico. Com grandes aumentos estruturas arredondadas medindo 0,4 micron são vistas no final do túnel queratinizado e na superfície da lesão.

Caracterizacióndde las endomicorrizas y siete gupos de microorganismos en agroosistemas del piedemonte amazónico, Cloombia / Characterization of the Endomycorrhizal and Seven Groups of Microorganisms in Agro Systems of the Amazon Piedmont

Este trabajo caracterizó la estructura funcional, la diversidad de la comunidad de endomicorrizas y el tamaño poblacional de siete grupos funcionales de microorganismos en suelos bajo cuatro diferentes usos de este o agrosistemas (bosque, cultivo de caña, pastura, y cultivo de café), los cuales fueron ubicados en una unidad productiva de la zona rural de Florencia, Caquetá. A partir de muestras de suelo superficial (0-20 cm) se determinaron las características fisicoquímicas del suelo, el tamaño de las poblaciones de siete grupos funcionales de microorganismos, la estructura de la comunidad de endomicorrizas (densidad de esporas, densidad de micelio total) y su diversidad (índices de riqueza, dominancia y equidad). Se encontró que el cambio en la cobertura natural, por el uso del suelo, tiene consecuencias en el tamaño poblacional de ciertos grupos bacterianos, así como en la estructura funcional y la diversidad de las endomicorrizas. También fue posible determinar que la estructura poblacional de la microbiota del suelo es particular a cada cobertura vegetal y que el tamaño poblacional está relacionado con el contenido de nutrientes del suelo, el cual proviene en gran parte de la mineralización de la materia orgánica.

This study characterized the functional structure, the diversity of the community of endomycorrhizae and population size of seven functional groups of microorganisms in soils under four different uses of land or agro systems (forest, cane, pasture, and cultivation of coffee), the which were located in a production unit in the rural area of Florencia-Caquetá. From samples of surface soil (0-20 cm) were determined agro ecosystems soil physical and chemical properties, the size of populations seven functional groups of microorganisms, the structure of the community to endomycorrhizae (spore density, density mycelium total) and diversity (richness, dominance, equity indices). It was found that the change in natural cover on the land use implications in population size of certain bacterial groups in the structure and functional diversity of endomycorrhizae. Was also be determined the population structure of soil microbiota is particular to each vegetation type and population size is strongly related to levels of soil nutrients, which come from the mineralization of organic matter.

Light and transmission electron microscopy of generalized dystrophic epidermolysis bullosa (Pasini's albopapuloid subtype) / Microscopia óptica e eletrônica de transmissão da epidermólise bolhosa distrófica generalizada (subtipo albo-papulóide de Pasini)

Pasini's albopapuloid epidermolysis bullosa is a very rare subtype of generalized dystrophic dominant epidermolyis bullosa. A 30 year-old white female patient presented since her childhood disseminated small blisters and papules. Light microscopy of a blister showed dermal-epidermal cleavage; moreover, focal areas of dermal-epidermal splitting were also observed. Transmission electron microscopy also identified focal areas of cleavage, which were seen below the lamina densa. It is important to recognize this condition as a variant of epidermolysis bullosa, since the most important cutaneous findings are generalized papules and not blisters and erosions as in other forms of epidermolysis bullosa.

A epidermólise bolhosa albo-papulóide de Pasini é uma variante rara da forma generalizada de epidermólise bolhosa distrófica dominante. Uma paciente de 30 anos apresenta desde a infância pápulas e bolhas disseminadas. A microscopia óptica de uma bolha demonstrou clivagem dermo-epidérmica; além disso áreas focais de desprendimento dermo-epidérmico foram encontradas. A microscopia eletrônica de transmissão identificou a clivagem abaixo da lâmina densa. É importante que se reconheça essa variante de epidermólise bolhosa, já que o aspecto clínico predominante são pápulas disseminadas e não bolhas como nas outras formas de epidermólise bolhosa.

Neurólise de plexo celíaco por via anterior guiada por tomografia computadorizada: relato de caso / CT-guided anterior celiac plexus neurolysis: case report

JUSTIFICATIVA E OBJETIVOS: A dor oncológica exige outras opções terapêuticas além do tratamento farmacológico para melhor controle e, portanto, deve-se sempre que possível utilizar técnicas e modalidades intervencionistas para controle da dor, pois assim pode--se oferecer aos pacientes melhor qualidade de vida e melhora da resposta terapêutica ao tratamento instituído.O objetivo deste estudo foi apresentar uma técnica intervencionista de simples execução, adequadamente tolerada pelo paciente, com ótimo resultado antálgico e isenta de maiores intercorrências.RELATO DO CASO: Paciente do sexo feminino,50 anos com quadro neoplásico decorrente de tumor de canal anal e dor refratária ao tratamento farmacológico multimodal com analgésicos. Submetida à neurólise de plexo celíaco por via anterior, guiado com tomografia computadorizada mediante punção única e injeção de álcool a 97%, obtendo controle efetivo do quadro álgico abdominal e retorno às tarefas da vida cotidiana.CONCLUSÃO: A neurólise do plexo celíaco por via anterior com punção única sob tomografia foi efetiva para o controle do quadro doloroso abdominal em paciente com tumor anal e metástase hepática irressecável.

BACKGROUND AND OBJECTIVES: Cancer pain requires other therapeutic options in addition to pharmacological treatment for better control. So, whenever possible, one should use interventionist pain control techniques and modalities to offer better quality of life and improve therapeutic response to treatment. This study aimed at presenting a simple interventionist technique,adequately tolerated by patients, with excellent pain relief and free of major intercurrences.CASE REPORT: Female patient, 50 years old with neoplasia resulting from anal canal tumor and pain refractory to multimodal analgesic treatment. CT-guided anterior celiac plexus neurolysis by single puncture and 97% alcohol injection has provided effective abdominal pain control and return to daily activities.CONCLUSION: CT-guided celiac plexus neurolysis with single puncture was effective to control abdominal pain in a patient with anal tumor and unresectable liver metastasis.

Classical Ehlers-Danlos syndrome: clinical, Histological and ultrastructural aspects / Síndrome de Ehlers-Danlos clássica: aspectos clínicos, histológicos e ultraestruturais

A 12-year-old boy with difficulty in wound healing and scars of unusual appearance was examined. Thin, shiny and protruding skin, characterizing pseudotumoral lesions, was observed on his knees and elbows. Loose joints and increased skin elasticity were also observed. Light microscopy showed rare collagen bundles and loosely dispersed collagen fibers. Irregularly distributed elastic tissue was observed, and transmission electron microscopy revealed disorganized collagen fibers. In cross sections under high magnifications, fibers of varying diameters could be seen, as well as an irregular fiber outline. Scanning electron microscopy of the dermis showed disorganized collagen fibers, which were rarely arranged in bundles. Isolated and crossed-over fibers were also found.

Paciente masculino de 12 anos relatou dificuldade em cicatrizar, seguido por cicatrizes de aspecto infrequente . A pele dos joelhos e cotovelos é fina, brilhante e protrusa, caracterizando pseudo- tumores. Além disso apresenta hiperelasticidade cutânea e articular. A microscopia óptica demonstrou raros feixes colágenos, as fibras colágenas encontram-se dispersas. O tecido elástico está presente e secundariamente irregular. A microscopia eletrônica de transmissão também observou fibras colágenas desorganizadas e com cortes transversais em grande aumento evidenciou diâmetros variados e contorno irregular das mesmas. A microscopia eletrônica de varredura da derme demonstrou raros feixes colágenos e fibras colágenas isoladas e entrecruzadas.

Crown-down preflaring in the determination of the first apical file

In this study, scanning electron microscopy (SEM) was used to evaluate the adaptation of the first apical file after preflaring in mesiobuccal (MB) and mesiolingual (ML) canals of mandibular molars considering the tactile sensibility as a reference. The mesial canals (n = 22) of human mandibular molar teeth were used, and the first instrument to bind to the working length was determined after preflaring and crown-down shaping. Digital images of the root apex were acquired and a single examiner determined the contact of the file with the walls using Image J software. The results showed that the file was in contact in 47.83 percent and 31.71 percent in the MB and ML canals, respectively. When the apexes are fused, the average was 40.03 percent. A descriptive analysis showed that the first apical file did not touch all dentin walls in any of the samples.

Cirugía de Mohs variedad en parafina en el Hospital Militar Central: una excelente elección / Mohs micrographic surgery modified by the use of tangential, formalin-fixed, paraffin- embedded histologic specimens (Slow Mohs): an excelent opcion

Introducción: La cirugía micrográfica de Mohs (CMM) es la técnica para la resección secuencial del cáncer de piel que permite el mejor control histológico y la conservación de tejido sano, dejando defectos quirúrgicos menores, reconstrucciones menos complejas y un buen resultado funcional y estético. La adaptación de la técnica clásica de Mohs en congelación a la variedad en parafina se ajusta al uso de los recursos, humanos, técnicos y físicos en los servicios de dermatología y patología del Hospital Militar Central, dispuestos para el manejo quirúrgico de los pacientes con tumores de piel de alto riesgo, disminuyendo costos, optimizando recursos y logrando resultados excelentes y reproducibles. Objetivos: Demostrar la efectividad de la CMM variedad en parafina en el tratamiento de los tumores malignos de piel de alto riesgo en el servicio de Dermatología del Hospital Militar Central. Materiales y Métodos: Estudio descriptivo, de serie de casos, donde se incluyeron los pacientes manejados con CMM variedad en parafina en el HOSMIC desde julio de 2005 hasta julio de 2008. Resultados: Se incluyó un total de 114 tumores, en 104 pacientes (primarios: 107, recurrentes: 7), con una evolución promedio de 20.5 meses. Se intervinieron 102 (89.4%) carcinomas basocelulares (CBC), 7 (6%) carcinomas escamocelulares (CEC), 1 (0,9%) léntigo maligno, 1 (0,9%) melanoma léntigo maligno, y 3 (2.6%) correspondientes a otro tipo de tumores. Se requirió un promedio de 1.3 estados de Mohs, erradicando el tumor en un solo tiempo en el 72% de los casos. El ahorro de tejido en CBC fue de 35,1% y 18,6% en CEC, al compararlo con los márgenes convencionales. La corrección quirúrgica fue realizada por el cirujano de Mohs en 78 casos (68.42%). Se comparó el informe final de patología con el de la biopsia inicial hallando una concordancia del 70%, en los restantes, 15%, correspondían a un patrón más agresivo que el inicial, generándose un riesgo adicional para estos pacientes en cirugía convencional. Se ha podido realizar seguimiento al 94%, (98), de los pacientes, sin presencia de recidivas en tres años del programa. Conclusiones: En el Hospital Militar Central los pacientes con cáncer de piel de alto riesgo se benefician de la técnica CMM variedad en parafina, la cual se ajusta a los recursos disponibles y brinda una alta tasa de curación con la posibilidad de ahorro de tejido sano, dejando defectos menores y permitiendo correcciones quirúrgicas por parte del servicio. Esta técnica puede ser reproducible con los recursos convencionales de histología en parafina bajo un entrenamiento previo en otras instituciones.

Síndrome dos cabelos impenteáveis (pili canaliculi): variabilidade clínica em 12 membros de uma família / Uncombable hair syndrome (pili trianguli et canaliculi): clinical variation in 12 members of one family

Pili canaliculi é alteração capilar rara, geralmente herdada de forma autossômica dominante, caracterizada por cabelos arrepiados, pertencendo ao espectro dos cabelos impenteáveis. Poucos estudos encontram ou explicitam sua variabilidade clínica. Uma família com 12 indivíduos afetados foi estudada, e o acometimento do couro cabeludo demonstrou grande variabilidade, desde cabelos arrepiados, difíceis de pentear, hipotricose leve ou intensa, até atriquia adquirida. O exame de microscopia óptica de cortes transversais dos cabelos, a estereomicroscopia e a microscopia eletrônica de varredura confirmaram o diagnóstico, demonstrando canais na superfície dos cabelos.

Pili canaliculi is rare hair disorder, usually inherited as an autosomal dominant trait, clinically characterized by uncombable hair. Few studies report its clinical variability. A family with 12 affected individuals was examined and involvement of hairs ranged from uncombable hairs, mild or intense hypotrichosis to acquired atrichia. Optical microscopy of hair cross sections, stereomicroscopy and scanning electron microscopy confirmed the diagnosis and showed hair shafts with characteristic longitudinal grooves.

Transmission electron microscopy of the preclinical phase of experimental phytophotodermatitis

OBJECTIVE: To examine the epidermis in induced phytophotodermatitis using transmission electron microscopy in order to detect histologic changes even before lesions are visible by light microscopy. INTRODUCTION: In the first six hours after the experimental induction of phytophotodermatitis, no changes are detectable by light microscopy. Only after 24 hours can keratinocyte necrosis and epidermal vacuolization be detected histologically, and blisters form by 48 hours. METHODS: The dorsum of four adult rats (Rattus norvegicus) was manually epilated. After painting the right half of the rat with the peel juice of Tahiti lemon, they were exposed to sunlight for eight minutes under general anesthesia. The left side was used as the control and exposed to sunlight only. Biopsies were performed immediately after photoinduction and one and two hours later, and the tissue was analyzed by transmission electron microscopy. RESULTS: No histological changes were seen on the control side. Immediately after induction, vacuolization in keratinocytes was observed. After one hour, desmosomal changes were also observed in addition to vacuolization. Keratin filaments were not attached to the desmosomal plaque. Free desmosomes and membrane ruptures were also seen. At two hours after induction, similar changes were found, and granular degeneration of keratin was also observed. DISCUSSION: The interaction of sunlight and psoralens generates a photoproduct that damages keratinocyte proteins, leading to keratinocyte necrosis and blister formation. CONCLUSIONS: Transmission electron microscopy can detect vacuolization, lesions of the membrane, and desmosomes in the first two hours after experimental induction of phytophotodermatitis.

Inoculo de hongos de micorrizasarbuscular en pasturas de Brachiaria decumbens(Poaceae) en zonas de loma y vega / Inoculum of Arbuscular Mycorrhizal Fungi on Brachiaria decumbens (Poaceae) Pastures in Valley and Hilly Terrain

Los factores que influyen en la distribución del inóculo de hongos micorrícicos arbusculares (micelio externo y esporas) son diversos. Entre ellos pueden mencionarse la especie vegetal predominante, el pH, la humedad del suelo, la conductividad, el contenido de fósforo, nutrientes y de metales pesados. Muchos de los reportes de la literatura son contradictorios y basados en estudios realizados en zonas templadas; en condiciones tropicales es difícil determinar los factores edáficos y ambientales que estimulan la producción de inóculo y la forma en que lo hacen. Brachiaria decumbens, como especie de pasto predominante en paisajes de loma y vega en el piedemonte amazónico colombiano, ha sido poco estudiada en su relación micorrícica. En este estudio se realizó la determinación de la densidad de esporas y micelio externo en 26 zonas cubiertas con B. decumbens, correspondientes a paisajes de loma y vega. Simultáneamente se valoraron el contenido de fósforo disponible (ppm), pH y humedad relativa del suelo (por ciento). Mediante correlaciones de Spearman (rangos) y análisis de varianza (ANDEVA) de una vía por KruscallWallis, se encontró que el inóculo se distribuye de forma diferente en loma y vega, siendo mayor la densidad de esporas en loma que en vega y más homogéneo en contenido de micelio externo en vega que en loma. No se encontró efecto del fósforo disponible, el pH y la humedad del suelo sobre la densidad de inóculo de HMA.

El tiempo de establecimiento de pasturas y su relacion con la micorriza arbuscular en paisajes de loma y vega / Time of Stablishment of Pastures and Their Relationship with Arbuscular Mycorrhiza in Hilly Terrain and Fertile Valley

El presente trabajo fue realizado para evaluar el efecto del tiempo (0-5 años, 5-10 años y más de 10 años) de establecimiento de pasturas de Brachiaria sp. sobre las poblaciones de hongos de micorriza arbuscular (HMA), su distribución de esporas, géneros, longitud de micelio extramatrical, colonización radical por HMA y otros hongos, en sistemas donde previamente existían bosques, en paisajes de loma y vega en Florencia, Caquetá, Colombia. Cualquiera que sea la edad de establecimiento de la pastura, predominan los géneros Glomus y Acaulospora; el cambio de la cobertura requiere de un periodo de más de diez años para que diferentes especies de HMA puedan recolonizar, adaptarse y diversificarse. En loma, la relación de Brachiaria sp. con los HMA disminuye con la edad, especialmente después de diez años; en vega se mantiene media y estable (21-50 por ciento), mientras la colonización radical por hongos diferentes a los HMA se incrementa, mostrando posiblemente un mecanismo de competencia por el espacio radical, o una acción conjunta. Finalmente, el micelio extramatrical y las esporas en loma y vega siguen tendencias variables (incremento, descenso o estabilidad) con la edad.