Biological and biochemical properties of the Brazilian Potamotrygon stingrays : Potamotrygon cf. scobina and Potamotrygon gr. orbignyi

Stingrays of the family Potamotrygonidae are widespread throughout river systems of South America that drain into the Atlantic Ocean. Some species are endemic to the most extreme freshwater environment of the Brazil and cause frequent accidents to humans. The envenomation causes immediate, local, and intense pain, soft tissue edema, and a variable extent of bleeding. The present study was carried out in order to describe the principal biological and some biochemical properties of the Brazilian Potamotrygon fish venoms (Potamotrygon cf. scobina and P. gr. orbignyi). Both stingray venoms induced significant edematogenic and nociceptive responses in mice. Edematogenic and nociceptive responses were reduced when the venom was incubated at 37 or 56 degrees C. The results showed striking augments of leukocytes rolling and adherent cells to the endothelium of cremaster mice induced by both venoms. The data also presented that injection of both venoms induced necrosis, low level of proteolytic activity, without inducing haemorrhage. But when the venoms of both stingray species were injected together with their mucus secretion, the necrotizing activity was more vigorous. The present study provided in vivo evidence of toxic effects for P. cf. scobina and P. gr. orbignyi venoms. (c) 2006 Elsevier Ltd. All fights reserved.

Conjunctival impression cytology in dogs

Objective Ocular conjunctivas of healthy dogs were studied by conjunctival impression cytology for evaluation of feasibility, protocol standardization, and normal cytologic pattern recognition of this technique.Animals studied Twenty healthy, adult, cross-breed dogs.Procedures Samples of the bulbar conjunctiva were collected after instillation of topical anesthetic drops at the ocular surface. Impression cytology was performed by applying asymmetric strips of Millipore filter on the superior temporal bulbar conjunctiva near the limbus. The filter strip was gently pressed against the conjunctiva for 5 s and removed with a peeling motion. Samples were immediately fixed in 95% ethyl alcohol, stained with periodic acid-Schiff and hematoxylin, and mounted on slides cover-slipped using synthetic resin. The slides were examined by light microscopy.Results Microscopic examination of the impressions revealed superficial, intermediate and basal epithelial cells arranged in sheets. Keratinized epithelial cells, goblet cells and leukocytes, as well as cellular debris and mucus were observed.Conclusions Feasibility of impression cytology for sampling the bulbar conjunctiva of the dog and the standardization the the proposed protocol was shown. The results allowed the recognition the the normal cytologic pattern of healthy conjunctivas in dogs.