RESUMO
We have evaluated biopsies from patients with atypical nodular and typical ulcerated lesions of cutaneous leishmaniasis, from leishmanin reactions and skin from normal individuals from Nicaragua, Honduras and Guatemala for the presence of inorganic particles using confocal microscopy with a polarised light source and conventional histopathological techniques. Analysis by semiquantitative confocal microscopy permitted the demonstration of significantly larger numbers of particles in atypical lesions. Silica and aluminium, important components of these particles, were less abundant in particles from normal skin. The histology of these atypical lesions, characterised by 'naked' sarcoidal granulomas with epithelioid differentiation but very few lymphocytes, was very similar to the histological reaction observed after 14 days in persisting inflammation at leishmanin skin test sites. The presence of these unusual lesions in areas of Central American countries characterised by the presence of large amounts of volcanic ash, as well the unexpectedly low prevalence of leprosy in Central America, suggest that environmental factors may contribute significantly to the frequency and clinical manifestations of these infections. Among possible environmental features, the presence of inorganic particles with immunomodulatory properties in the skin may be a significant factor.
Assuntos
Corpos Estranhos/diagnóstico , Leishmaniose Cutânea/imunologia , Hanseníase/imunologia , Pele , Alumínio/análise , América Central/epidemiologia , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análise , Corpos Estranhos/imunologia , Granuloma de Corpo Estranho/etiologia , Granuloma de Corpo Estranho/patologia , Humanos , Leishmaniose Cutânea/epidemiologia , Hanseníase/epidemiologia , Dióxido de Silício/análise , Erupções Vulcânicas/efeitos adversos , Erupções Vulcânicas/análiseRESUMO
In this work, we report an alternative assay for the determination of the inhibitory effect on monoamine oxidase B (MAO-B) activity of probe compounds. Enzyme MAO-B exhibits fluorescence emissions when it is excited at 412 nm. Using an inexpensive blue LED-like excitation source, we measured the quenching of fluorescence intensity of MAO-B enzyme during the reaction with inhibitors. The applicability of the procedure is demonstrated by assays with l-deprenyl and berberine as inhibitors through the use of fluorescence studies. The IC(50) values of l-deprenyl and berberine were 0.04 and 90 microM, respectively. The K(I) values were 0.020 and 47 microM for l-deprenyl and berberine, respectively. These IC(50) and K(I) values were similar to the values obtained with a standard method. These results demonstrate the feasibility of this method as an alternative to follow the inhibitory effect on MAO-B.
Assuntos
Monoaminoxidase/metabolismo , Espectrometria de Fluorescência/métodos , Animais , Benzilaminas/química , Berberina/química , Berberina/farmacologia , Relação Dose-Resposta a Droga , Cinética , Luz , Camundongos , Mitocôndrias Hepáticas/efeitos dos fármacos , Mitocôndrias Hepáticas/metabolismo , Inibidores da Monoaminoxidase/metabolismo , Selegilina/química , Selegilina/farmacologiaRESUMO
Biopsies of 71 cases of atypical cutaneous leishmaniasis from Costa Rican patients were evaluated by histopathological procedures and attempts were made to culture Leishmania from nine biopsies. Leishmanin skin tests were carried out in 31 patients and 112 healthy individuals. Additional biopsies from 19 patients from Nicaragua were evaluated by routine histopathology. Ten biopsies were studied by confocal and nine by scanning electron microscopy. Inorganic material was analysed using an electron probe for microanalysis. Leishmania parasites were isolated from only two biopsies, but 90.3% of the patients from Costa Rica were leishmanin-positive, as were 27.7% of healthy individuals. Routine histopathological studies revealed naked granulomas formed by differentiated macrophages. Abundant inorganic material was observed in sections examined by confocal microscopy. Electron probe analysis revealed that silica and aluminium were the predominant elements in large particles. We postulate that the presence of this inorganic material, possibly of volcanic origin, in the skin may modulate the immunological response to Leishmania and may inhibit visceralization in the cases caused by Leishmania chagasi.
Assuntos
Leishmaniose Cutânea/patologia , Adolescente , Adulto , Alumínio/análise , Animais , Costa Rica/epidemiologia , Exposição Ambiental/efeitos adversos , Feminino , Granuloma/patologia , Humanos , Leishmania/isolamento & purificação , Leishmaniose Cutânea/epidemiologia , Leishmaniose Cutânea/parasitologia , Masculino , Nicarágua/epidemiologia , Dióxido de Silício/análise , Pele/metabolismo , Pele/patologia , Testes CutâneosRESUMO
We present a new scheme for a pump-probe mode-mismatched thermal lensing experiment aimed at extracting the value of low-absorbing components in the presence of a high-absorbing background. The method allows for the use of large path-length samples. Changes in the background absorption of a column of ethanol of 20 cm of 1% and a pollutant concentration detection limit of 0.04 ppm are obtained when using a pump light power of 34 mW.
Assuntos
Análise Espectral/instrumentação , Análise Espectral/métodos , Análise Diferencial Térmica , Etanol/análise , Lasers , Refratometria , Sensibilidade e Especificidade , Temperatura , Poluentes Químicos da Água/análiseRESUMO
In this work we present spectroscopic study of Boldine (aporphine alkaloid) that possesses important biological activities, in particular, in interaction with the promastigotes of Leishmania mexicana. The results show the applicability of autofluorescence of this drug to determinate the possible mechanism of its biological action. The blue shift and hyperchromic effect in the emission spectrum of the drug in interaction with the parasite cells indicate an energy transference process between them. The morphological change of cell shape of the promastigotes treated with the drug is observed using confocal microscopy. This morphological cell-shape transformation evidences an important interaction between the drug studied and some protein of the parasite cell. Here we describe for the first time the fluorescence properties of the Boldine in the promastigotes of L. mexicana.
Assuntos
Antiprotozoários/química , Antiprotozoários/farmacologia , Leishmania mexicana/efeitos dos fármacos , Animais , Aporfinas/química , Aporfinas/farmacologia , Leishmania mexicana/citologia , Microscopia Confocal , Espectrometria de Fluorescência/instrumentação , Espectrometria de Fluorescência/métodos , Espectrofotometria/instrumentação , Espectrofotometria/métodosRESUMO
Coeliac disease is uncommon in populations of non-European origin. Two English born West Indian children with coeliac disease are presented. The diagnosis should be considered in children of West Indian origin with chronic diarrhoea.
Assuntos
Doença Celíaca/etnologia , Doença Celíaca/imunologia , Inglaterra , Feminino , Antígenos HLA-D/análise , Humanos , Lactente , Masculino , Índias Ocidentais/etnologiaRESUMO
Although gallbladder carcinoma is one of the most frequent neoplasms in Chile, there is limited information about the molecular changes involved in its pathogenesis. We investigated the incidence of ras gene mutations and loss of heterozygosity (LOH) at the following genes/loci: p53, DCC, rb, 5q 3p, 8p, and 9p. We precisely microdissected 194 relevant areas from paraffin-embedded microslides from 25 gallbladder carcinomas and their accompanying nonneoplastic lesions (which were present in 15 cases) from patients in Chile. The specimens were analyzed by PCR-based assays for LOH, and we designed a RFLP method for ras mutations and immunohistochemistry for p53 protein overexpression. We determined that LOH at p53 (91%), 9p (50%), 8p (44%) and DCC (31%) are frequent events and that LOH at p53, 9p, and DCC are early events, while ras mutations and LOH at 3p, rb, and 5q occurred occasionally. LOH at p53 occurred more frequently and earlier than protein overexpression. The mean number of mutations present in invasive carcinomas was 2.1, and in six cases, LOH at the p53 gene was the sole mutation detected. The same allele was lost in 61 (93%) of 71 nonneoplastic foci as in the corresponding invasive carcinomas for all four mutations studied. The odds of this occurring by chance are approximately 4 x 10(-15). Although clonality cannot be excluded, allelic loss appears to be highly directed, but the mechanism for allele-specific mutations remains to be determined.