A Toxic Ocular Reaction

Abstract

Summary and Conclusions The work embodied in this paper demonstrates that Shwartzman toxins are capable of producing a primary ocular reaction in rabbits, named the toxic ocular reaction. The reaction consists of intense iridoconjunctival hyperemia and coagulation of the aqueous humor after its aspiration. It appears several minutes after the intravenous injection of toxin, reaches its maximal intensity in a few hours, and is notably reduced or has completely disappeared in about twelve hours. The smallest amount of toxin which, by intravenous injection, induces aqueous humor coagulation is termed the minimal coagulating dose. The reaction was also obtained using the intra-arterial and intraabdominal routes and a highly vascularized area of the skin. However, the intestinal and conjunctival routes proved non-effective. Protection against the ocular reaction was afforded by previous intracutaneous or intravenous injection of rabbits with Shwartzman filtrates or by moccasin snake venom injection. Toxins kept their potency for several months when undiluted preparations were stored in the refrigerator. The toxic ocular principles did not pass through dialyzing membranes, showed resistance to heat at high pressure, were definitely weakened by the addition of formaldehyde, and were specifically neutralized by Shwartzman antitoxins. This reaction was reproduced in cats and dogs but failed to appear in other usual laboratory animals, even guinea-pigs in which, in a certain percentage, the Shwartzman phenomenon may be elicited. The toxic ocular reaction was obtained in approximately 95 per cent of a large number of rabbits injected intravenously with 10 or more minimal coagulating doses per kilo of body weight. It thus represents a new property of the Shwartzman toxins, and indicates their marked primary toxicity for the rabbit's uveal tract.