Profound hypersensitivity reaction following gaboon viper “bite”

8th World ~ on ~,dm.l~ Phmt and Microbial To~t~ 593 STRUCTURAL AND BIDLOGIC~L b-.uulXS ON A FIBRINOLYTIC ENZYME FROM AGKISTRODON ~RTRIX C O N T O R T R I X S N A K E VENOM. By F.S. M a ~ K.N.N. R ~ d y stud A. Pe~don. Dept of Bloclmmistry and C o m p ~ . . m d v e Cmsc~ Cemt~, USC School of Medicine, Los A u i ~ m , California 90033, U ~ . A . A fi~'.~-~lytlcmssTme has been pm4fled from A. c . ~ (muthm~ copperhead) wmom by combination of mqumst~l cl=omato8~Pby - - C3d-cellulo~, ~ p l m d n G-100 stud bmummtdiueSe~o~, m~d ln~Ps~tiw~ flat plate tsoelectric focuzinS. As determined by SDS-poly~n~e,-;A~ 8el e l e c t r o p h o r u t s the purified enzyme b a dugle chain 81ycoprotein with a ,-olecul~" welsht of approximately 25,000. The lsoelectric point is between 6.5--6.8. The ensyme is free of tIn.omb/nHke activity snd d o u not hydmlyse sarine p m t e u e specific c h r o m o p n i c s u b s t n t e l c~ basic amino acid esters. The W..y.,e % inhibited x.apidly by 10raM EDTA, .tetraethylmmpentamine and o-ph--nthmnne, m ~ that it is a met-l~oteim,m. ~ b not inhibited by dflmpmpylfluca-oplmsphate. Disulfide bcmd cleavage by Tram dithtothreitol rapidly inactivated the en.y~e in the presence or absence of urea. C ~ t m l studies showed that afte~ ezposure to 8M urea, dihation of the emsyme-mrea mixture allows reseneraUon of 60% activity. Analysis "~"Z e i t h ~ *1=..,yl chloride o~ Nqumsttal Edmsm d e ~ a d a U ~ of the venom emzTme e ~ i n t e d from polyacrT1• ,-t~e gels, 8 u u ~ t ~ t that the mnino-tm~inus is blocked. Onsoins studies ~emaled that cyanogem bromide cleavage of the ensyme ln.OdUCed sevmstl f~-aEments u detm.mined by SDSacry~-,-4~- slab gel e l e c t r o ~ using the method of Swank ~nd Mun~es. The ensyms desradm fibrin clots in blood ~ senun, and acts directly on fibrin fc~.med by thrombin clotting of h,,.-~m fibrinosen. E~=y.~e activity can be rams.rod either by fibrin plate clearsnce o~ by u o c a m i n hydrolwds. The ensyme can be detected - - a=ylamide 8 e k by a fibrin overlay technique. The emsyme acts directly c~ fibrin snd does not require plumtnoKen for ita actlc=. Separate studies revealed that the emzyme does not activate ;-,m~n phunninoKen u Judged e i t h ~ by chromoKenic substz~te assay ca- b7 SDS-polyacryhunide gel e l e c t o r . Studies in collaboration with 3.,7. B o o . t e l . u , University of Califonda, San Dieso, revealed that the e ~ . . ~ e , has thrombolytic activity in • ~ arterial tln~mbcsis model system in rabbits. With highly ', puriF;ed emsyme, m ~ i w a l toxicity ~ ~ effects were observed, and rabbit or human clots were rapidly lysed. These studies s~e presently cc=t4,-,;,,~. Supported in part by PHS Grant No. HI. 31389, awarded by the NHLBI, DHHS, and by Cortech, V,,c., Denver, Colorado. ~ C E Swank, I~T. and Munkres, K.D. (1971))~--!~Biochem. 3% 4~L KEY WORDS ASk~atnxtms ~ c,~torU4s; flbrtno~Tttc metanoproteinase; px.otein . t ~ u c t u ~

PROFOUND HYPERSENSITIVITY REACTION FOLLOWING GABOON VIPER "BITE" By N.A.MARSH, R.D.G.THEAKSTON* and B.C.WHALER. Department of Physiology, Queen Elizabeth College, Campden Hill Road, London W8 7AH and *Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA. We have kept specimens of East African Gaboon viper (Bitis ~abonica ~abonica) over the past 15 years during which time one of us has become acutely sensitized to dried venom, the reaction typically being a rapid onset of "blood-shot" eyes and oedematous eyelids. In November 1983 having milked a consignment of West African Gaboon vipers ([email protected]) for the first time, the sensitized handler received a deep stab wound from a single fang in the dorsum of the right thumb. This occurred whilst the anaesthetized snake was being force-fed; it began to regain consciousness and managed to erect its right fang. Within 40 min, the victim was admitted to hospital and had developed a spectacular generalized urticarial reaction but no other abnormal signs were detected and the blood coagulation profile was normal. The patient was assessed as having a marked hypersensitivity reaction without systemic poisoning, thus antivenom was withheld and treatment effected with 200 mg hydrocortisone i.v., 10 mg chlorpheniramine (Piriton) i.v. and 0.5 ml tetanus toxoid i.m. The patient was retained in Intensive Care Unit overnight and discharged symptom-free the next day. Subsequent ELISA measurements revealed a very high antibody level after 5 weeks which gradually declined to low levels after one year. There were no antibodies detectable in a sample of blood draw~ within 60 min of the incident whilst venom antigen could only be detected in this initial blood sample. The level was 4.6 ng/ml suggesting that a very small amount of venom entered the systemic circulation, probably around 10-15 ~g protein. This case highlights the problems of venom hypersensitivity and also serves as a salutary lesson in maintaining extreme caution at all times when handling captive venomous animals. Gaboon viper;

KEY WORDS snake bite; venom hypersensitivity