A flow cytometric approach to the study of crustacean cellular immunity.

Responses of hemocytes from the crayfish Procambarus zonangulus to stimulation by fungal cell walls (zymosan A) were measured by flow cytometry. Changes in hemocyte physical characteristics were assessed flow cytometrically using forward- and side-scatter light parameters, and viability was measured by two-color fluorescent staining with calcein-AM and ethidium homodimer 1. The main effects of zymosan A on crayfish hemocytes were reduction in cell size and viability compared to control mixtures (hemocytes in buffer only). Adding diethyldithiocarbamic acid, an inhibitor of phenoloxidase, to hemocyte and zymosan mixtures delayed the time course of cell size reduction and cell death compared to zymosan-positive controls. The inclusion of trypsin inhibitor in reaction mixtures further delayed the reduction in hemocyte size and cell death, thereby indicating that a proteolytic cascade, along with prophenoloxidase activation, played a key role in generating signal molecules which mediate these cellular responses. In addition to traditional methods such as microscopy and protein chemistry, flow cytometry can provide a simple, reproducible, and sensitive method for evaluating invertebrate hemocyte responses to immunological stimuli.

Cresolase, catecholase and laccase activities in haemocytes of the red swamp crayfish.

Phenoloxidase activity in crayfish haemocyte lysates and extracts of haemocyte membranes were studied using native PAGE and SDS-PAGE gels and staining for cresolase, catecholase and laccase activities. The activation of the proenzyme, prophenoloxidase to phenoloxidase, in native PAGE was demonstrated following exposure to SDS. By staining samples separated in SDS-PAGE followed by renaturation, a high molecular mass phenoloxidase activity was identified in both the soluble and membrane fractions of haemocyte preparations. The membrane-associated activity appeared at only relatively high molecular mass (> 300 kDa), and could easily be eluted from membranes using detergents or NaCl. Further, this membrane-associated activity has a catecholase activity but not the cresolase activity seen in the soluble preparations. In addition, several other phenoloxidase enzymes were identified with different relative mobilities (250, 80, 72 and 10 kDa). Crayfish haemocytes also contained laccase activity, thought to be restricted to cuticle sclerotisation in the integument. Laccase activity in haemocytes might aid in the formation of capsule used to contain pathogens.

La biopsia endoscópica en cáncer gástrico

Con el fin de comparor lo déscrito en la literatura mundial sobre numero y sitio de la toma de la biopsia en lesiones gástricas sospechosas de malignidad realizamos en 41 pacientes un estudio prospéctivo,abierto,a los cuales se les tomaron 9 fragmentos,analizados en grupos de tres.Con la información obtenida se clasificaron los apacientes y se establecio que la sensibilidad de la biopsia gástrica aumenta en la medida que se toma un mayor número de fragmentos del area sospechosa

Evaluación de Cisapride en Reflujo Gastroesofágico

En el presente trabajo se estudiaron 16 pacientes con sintomatología clínica de reflujo gastroesofágico, mediante esofagogastroscopia, biopsia de las zonas de esofagitis y gamagrafía para reflujo. Posteriormente se les administró Cisapride 10 mg antes de cada comida y se revaluaron con igual metodología 4 semanas después, anotándose todos los síntomas durante el estudio. Se recurrió a la prueba de Wilcoxon para análisis estadístico. Se analizan los resultados y finalmente se hace una comparación descriptiva con otros fármacos de efecto análogo