ABSTRACT
Copperhead envenomation cases reported in the literature frequently lack identification of the subspecies of copperhead responsible for the envenomation. Whether subspecific identity would be useful in predicting possible different toxicity profiles may have clinical relevance. We report here the clinical profiles from envenomations involving 3 different subspecies of captive adult copperhead snakes--the southern copperhead (Agkistrodon contortrix contortrix), the northern copperhead (Agkistrodon contortrix mokasen), and the broad-banded copperhead (Agkistrodon contortrix laticinctus). The bites occurred in the north-central region of the US where none of these subspecies are endemic and involved a professional and 2 amateur herpetologists. The victims were adult males with no previous history of venomous snake bite, and all bites were evidenced by fang puncture marks to their index finger or thumb. Envenomations from the broad-banded and northern copperhead subspecies caused localized symptoms of pain, edema and ecchymosis. In addition to these symptoms, southern copperhead envenomation resulted in a more severe clinical toxicity profile as evidenced by propulsive emesis, diarrhea and hematuria. Whether these differences in observed clinical toxicity were the result of unique subspecific venom pharmacological actions is an interesting question. However, independent of the copperhead subspecies involved, conservative medical management was effective in each case.
Subject(s)
Agkistrodon/physiology , Snake Bites/diagnosis , Snake Venoms/toxicity , Adult , Agkistrodon/classification , Animals , Antidotes/therapeutic use , Humans , Male , Pain/drug therapy , Species SpecificityABSTRACT
Three phospholipase A2 (PLA2) inhibitors (PLI) have been purified from the blood plasma of the Chinese mamushi, Agkistrodon blomhoffii siniticus; 1 of these, PLIgamma, contains 2 homologous subunits, PLIgamma-A and PLIgamma-B. The cDNAs encoding these 2 subunits of PLIgamma were isolated from a liver cDNA library by using fragments from polymerase chain reaction amplifications as probes and sequenced. The respective nucleotide sequences encoded 19-residue signal sequences, followed by 181-residue proteins. The calculated molecular masses were 20123 and 20150 Da for the PLIgamma-A and PLIgamma-B subunits, respectively; and PLIgamma-A included a N-linked carbohydrate site at Asn-157. The sequences of these subunits contained 2 internal repeats of disulfide-bonding pattern characteristic to those of urokinase-type plasminogen activator receptor and members of the Ly-6 superfamily. A phylogenetic analysis comparing the amino acid sequences of PLIgamma-A and PLIgamma-B with those for other snakes revealed that the gene duplication leading to these 2 subunits occurred before the divergence of Viperidae and Elapidae.
Subject(s)
Agkistrodon/blood , Glycoproteins/genetics , Phosphodiesterase Inhibitors/blood , Phospholipases A/antagonists & inhibitors , Agkistrodon/classification , Agkistrodon/genetics , Amino Acid Sequence , Animals , Base Sequence , Cloning, Molecular , Conserved Sequence , DNA, Complementary , Disulfides/chemistry , Gene Library , Glycoproteins/chemistry , Glycoproteins/pharmacology , Macromolecular Substances , Molecular Sequence Data , Molecular Weight , Phospholipases A2 , Phylogeny , Polymerase Chain Reaction , Repetitive Sequences, Amino Acid , Sequence Alignment , Sequence Homology, Amino AcidABSTRACT
Characteristics of poisonous snakes and their toxines are described. The appearance and biology of all European poisonous snakes, eight vipers (family Viperidae) and one opisthoglyph colubride snake (family Colubridae) are given in detail.
Subject(s)
Colubridae/classification , Viper Venoms , Viperidae/classification , Agkistrodon/classification , Animals , EuropeABSTRACT
AIM: To study the synergistic effect of thrombin-like enzymes (TLE) of Dienagkistrodon acutus (DA) and Agkistrodon halys (AH) venoms. METHODS: TLE were isolated from venoms of DA and AH by successive column chromatography. Effects of combination of DATLE and AHTLE and related factors on the clotting time and clot quality were tested in vitro. RESULTS: One coagulation unit was 2.7 micrograms for DATLE and 304.4 micrograms, for AHTLE with reference standard of thrombin (42.2 micrograms). TLE-induced clot was a fibrin monomer which was fragile and did not retract. Combination of AHTLE and DATLE shortened the clotting time and decreased the solubility of the clot in urea 5 mol.L-1. When subthreshold concentration of thrombin or physiological concentration of Ca2+ was added, the clotting time was further shortened, the clot was no longer soluble in urea and retracted well, and the resistance of the clot to plasmin degradation was increased. CONCLUSION: A synergistic effect of DATLE and AHTLE accelerated hemocoagulation and improve clot quality.
