Two novel dermonecrotic toxins LiRecDT4 and LiRecDT5 from brown spider (Loxosceles intermedia) venom: from cloning to functional characterization.

Loxoscelism (the condition produced by the bite of brown spiders) has been reported worldwide, but especially in warmer regions. Clinical manifestations include skin necrosis with gravitational spreading while systemic loxoscelism may include renal failure, hemolysis and thrombocytopenia. The venom contains several toxins, of which the best biochemically and biologically studied is the dermonecrotic toxin, a phospholipase-D.

Hyaluronidases in Loxosceles intermedia (Brown spider) venom are endo-beta-N-acetyl-d-hexosaminidases hydrolases.

In studying Loxosceles venom, we detected degradation of purified hyaluronic acid (HA) and hydrolysis of purified chondroitin sulphate (CS) while neither dermatan sulphate, heparin or heparan sulphate were affected. In addition, with HA-degrading kinetic assays, we show that a hydrolase enzyme was involved in the HA cleavage. By use of the Reissig colorimetric reaction, we found that venom hyaluronidase is an endo-beta-N-acetyl-d-hexosaminidase that generates terminal N-acetylglucosamine residues upon cleavage of HA.

The effect of brown spider venom on endothelial cell morphology and adhesive structures.

Spiders of the Loxosceles genus have been responsible for severe clinical cases of envenomation worldwide. Accidents involving brown spiders can cause dermonecrotic injury, hemorrhage, hemolysis, platelet aggregation and renal failure. Histological findings of animals treated by venom have shown subendothelial blebs, vacuoles and endothelial cell membrane degeneration of blood vessel walls, as well as fibrin and thrombus formation.

Molecular cloning and functional characterization of two isoforms of dermonecrotic toxin from Loxosceles intermedia (brown spider) venom gland.

Brown spider (Genus Loxosceles) bites are normally associated with necrotic skin degeneration, gravitational spreading, massive inflammatory response at injured region, platelet aggregation causing thrombocytopenia and renal disturbances. Brown spider venom has a complex composition containing many different toxins, of which a well-studied component is the dermonecrotic toxin. This toxin alone may produce necrotic lesions, inflammatory response and platelet aggregation.

Concentration of hyaluronic acid in primary open-angle glaucoma aqueous humor.

We compared the concentration of hyaluronic acid in the aqueous humor of primary open-angle glaucoma (POAG) patients and non-glaucomatous patients. Aqueous humor samples were obtained from 22 patients just before trabeculectomy for clinically uncontrolled POAG (POAG group). Aqueous humor (0.