Aumento de antioxidantes en sangre y de las concentraciones de selenio en pacientes negros con fase activa de vitíligo / Increased in total blood antioxidant status and selenium levels in black patients with active vitiligo

Antecedentes; El estrés oxidativo es un fenómeno importante en la muerte de los melanocitos en el vitiligo. Recientemente se ha encontrado una acumulación de peróxido de hidrógeno (H2O2) y niveles bajos de catalasa en la epidermis de pacientes con vitiligo. Se han visto pocas alteraciones de los antioxidantes en la sangre de pacientes con vitiligo, excepto una elevación del selenio. No se han realizado estudios sobre el estrés oxidativo hasta ahora, en pacientes con un fototipo VI de piel (clasificación de Fitzpatrick). Objetivo: Estudiar el estado antioxidante en la sangre de pacientes negros con vitíligo generalizado activo. Métodos: Se evaluaron el estado antioxidante total Randox, y las concentraciones de selenio, ferritina, transferrina, ceruloplasmina, tocoferol y retinal en muestras de sangre de los pacientes de piel negra de las indias Occidentales Francesas (de Martinica) con lesiones activas recientes de vitíligo y de 8 voluntarios sanos equiparados en edad y sexo. Resultados: El estado antioxidante total de la sangre y las concentraciones de selenio aumentaron significativamente en los pacientes con vitiligo, en comparación con los controles equiparados en sexo y edad (p<0,01 y p<0,02, respectivamente). No se modificaron significativamente las concentraciones en sangre de ferritina, transferrina, ceruloplasmina, retinol y tocoferol. Conclusiones: Este es el primer trabajo sobre el estado antioxidante global en sangre en el vitíligo. El aumento del estado antioxidante total en sangre observado en pacientes negros fue un resultado inesperado que necesita confirmarse y explicarse por otros estudios. El aumento espontáneo de las concentraciones de selenio podría ser interesante, puesto que este elemento ha sido recomendado en el tratamiento del vitíligo (AU)

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Schistosoma mansoni: in vitro adhesion of parasite eggs to the vascular endothelium. Subsequent inhibition by a monoclonal antibody directed to a carbohydrate epitope.

Schistosoma mansoni eggs come into direct contact with the vascular endothelium, particularly in the postcapillary venules of the mesenteric tract (oviposition site). We investigated the adhesion of eggs to endothelial cells in a static in vitro assay and in a flow-based in vitro assay. Live S. mansoni eggs rapidly attached, in a time-dependent manner, to the human endothelial cell line ECV 304, but not KOH-treated eggs. Activation of ECV monolayers with interleukin-1 promoted live S. mansoni eggs adhesion. An in vitro flow-based assay of human umbilical vein endothelial cells (HUVEC) showed the influence of wall shear stresses on the attachment of eggs to endothelial cells, particularly under postcapillary venule shear stress conditions. Interleukin-1 activation of HUVEC promoted adhesion between live eggs and endothelial cells. Higher wall shear stresses were needed to obtain the detachment of eggs from activated endothelial cells than control cells. Preincubation of interleukin-1-activated HUVEC, in a static in vitro assay, with monoclonal antibodies specific for intercellular adhesion molecule-1, E-selectin, and vascular cell adhesion molecule-1 significantly decreased adhesion of live eggs. Previous studies have shown that a monoclonal antibody specific for a schistosome carbohydrate epitope abundant in eggs is related to the Lewis X antigen. In this study, the anti-Lewis X-specific monoclonal antibody was used for adhesion-inhibition assays. Preincubation of eggs with this monoclonal antibody significantly decreased adhesion of live eggs to interleukin-1-activated HUVEC cultured in vitro. These results suggest that surface adhesion molecules, expressed by endothelial cells under conditions of interleukin-1 activation, directly participate in egg adhesion and that egg carbohydrate antigens play an important role in live S. mansoni egg adhesion to the vascular endothelium.

[Immunofluorescence reaction of antibodies directed against the intestinal epithelium of Schistosoma mansoni. VI. Immunolocalization of a carbohydrate epitope at different developmental stages]. / Etude par la réaction d'immunofluorescence des anticorps dirigés contre l'épithélium intestinal de Schistosoma mansoni. VI. Immunolocalisation d'un épitope glucidique aux différents stades évolutifs.

In the course of previous works, we described an IgM monoclonal antibody directed to a carbohydrate epitope located on the gut epithelium surface of the Schistosoma mansoni adult worm. We provided evidence that this epitope was present in all stages of the parasite and was particularly abundant in eggs. The current work was performed in order to specify the epitope localisation, at each stage, by immunohistochemical techniques. The epitope appears to be located on the peripheral membranes of the adult worm, while it is produced by the alive miracidium in the eggs located in the tissues and subsequently spread out inside the periovular granuloma. Moreover, in adult worms, the observed structure presents itself as a soluble form in organic solvents; on the other hand, in eggs, the epitope was essentially found made of an hydrosoluble substance. These datas can explain why, in experimentally infected mice, the epitope is mainly determined in urines at the sixth week of infestation, when eggs are settled down in the tissues. Besides, the inhibition of the monoclonal antibody fixation by a pentose which contains the Lewis X antigen, painted out that the carbohydrate structure recognised by the monoclonal antibody could be the Lewis X antigen or a very closed structure.

Endothelium activation related increase of soluble intercellular adhesion molecule-1 in human schistosomiasis. Lack of correlation with serology.

Soluble intercellular adhesion molecule-1 (sICAM-1) level was measured in sera from 41 patients with Schistosoma mansoni schistosomiasis and compared with the sICAM-1 level in 41 healthy subjects. A significant increase in serum sICAM-1 was observed in patients with schistosomiasis compared with control subjects. As they were inhabitants of the French Antilles, the patients were, however, not settled in a malaria endemic zone, allowing this cause of sICAM-1 enhancement to be eliminated. No correlation was found between the level of sICAM-1 and the schistosomiasis serological titre. Such results favour the hypothesis of an activation of vascular endothelial cells due to egg deposition.

[Chronic urticaria and toxocara canis infection. A case-control study]. / Urticaire chronique et Toxocara canis. Etude cas-témoins.

INTRODUCTION: The cause of chronic urticaria remains unknown very often. Having noted several cases of chronic urticaria associated with antibodies to Toxocara canis, and lacking any other explanation, we set-up a case-control study. PATIENTS AND METHODS: Between November 1992 and April 1993, 51 adults or children with chronic urticaria (cases) who had been examined at least once at one of the three dermatology units of the Bordeaux University Hospital were matched to controls who had neither signs nor symptoms of chronic urticaria. The presence of antibodies to T. canis was measured by ELISA and Western blot. RESULTS: The frequency of T. canis was 64.7 p. 100 in cases and 21 p. 100 in controls (p < 0.0001) with an odds ratio of 6.9 (95 p. 100 CI: 2.9-16.3). Cases with antibodies to T. canis were more frequently in contact with pets (84 vs 50 p. 100, p < 0.001). Of the 33 cases of chronic urticaria with antibodies to T. canis, 14 have been treated with thiabendazole or ivermectin and after a one-year follow-up, 5 (36 p. 100) were cured and 4 (29 p. 100) had improvement. No improvement occurred in the 12/19 cases not specifically treated. CONCLUSION: The strong association between the presence of antibodies to Toxocara canis and chronic urticaria is unlikely to be due to chance. A causal relation is difficult to establish, however. Our findings should prompt further investigation of a role for Toxocara canis in chronic urticaria and the evaluation of therapeutic interventions. Preventive measures include deworming pets (dogs particularly), enclosing kitchen gardens, and handwashing before meals. A systematic measure of Toxocara canis in patients with chronic urticaria is recommended especially when in contact with dogs. Early and specific treatments can be applied on knowledge we already have.

[Study by the immunofluorescence reaction of antibodies directed against antigens of the gut epithelium of Schistosoma mansoni. V. Modulation of granulomatous reaction around the egg under the influence of an IgM monoclonal antibody]. / Etude par la réaction d'mmunofluorescence des anticorps dirigés contre les antigènes de l'épithélium intestinal de Schistosoma mansoni. V. Modulation de la réaction granulomateuse autour de l'oeuf sous l'influence d'un anticorps monoclonal de classe IgM.

The periovular granulomatous reaction has been reduced in vivo by an IgM monoclonal antibody. The granulomatous reaction has been obtained either in unsensitized, or sensitized as well as immunized mouse. The granulomatous reduction could be explained by a decrease in egg viability, owing to the fact that the monoclonal antibody is lethal against an in vitro miracidium suspension.

[Evaluation of an indirect hemagglutination test for the serodiagnosis of amebiasis]. / Evaluation d'un test d'hémagglutination indirecte amibiase (HAI) pour le serodiagnostic de l'amibiase.

167 sera have been tested to appreciate the value of an indirect hemagglutination test (Amibiase HAI FUMOUZE) comparatively to an agglutination test of sensibilized particles of latex (Bichro latex Amibe Fumouze BLA) Amibiase HAI test comes out as sensitive and specific for the detection of antibodies in patients suffering from visceral amoebiasis. But some antibodies are also detected in patients with an antecedent of amoebiasis, as it is usually the case with some other techniques. A high positivity of the indirect hemagglutination test, and the concordance between the test HAI and the BLA one are in favour of a visceral amoebiasis. While lower rates or discrepancy between the two tests may evoke an hidden infestation in patients coming out or originated from endemic zones.