Australian Snake Venoms Research Articles

Effects of paradoxin, a β-neurotoxin from Australian inland Taipan snake (Oxyuranus microlepidotus) venom: Studies in rodent central nervous system

Effects of paradoxin, a β-neurotoxin from Australian inland Taipan snake (Oxyuranus microlepidotus) venom: Studies in rodent central nervous system

Efficacy and Potency of Antivenoms in Neutralizing the Procoagulant Effects of Australian Snake Venoms in Dog and Human Plasma

The efficacy and potency of Commonwealth Serum Laboratories (CSL) snake antivenoms in neutralizing the procoagulant action of Australian snake venoms was studied in vitro. The procoagulant action of venoms from Tiger, Brown and Taipan Snakes were measured in pooled canine or pooled human plasma. Mixtures of the venoms and their appropriate antivenoms, ranging from 0.1 to 15 times the recommended neutralizing dose of antivenom were then added to pooled canine or pooled human plasma and the efficacy and potency of the antivenoms in preventing the procoagulant action was measured. Neutralization was achieved by the addition of the appropriate antivenom in concentrations of 0.5 (Taipan), 10 (Tiger), 10 (Gwardar), 15 (Dugite) and an estimated 20 (Common Brown) times the dose expected. Similar results were obtained in canine and human plasma. The potency of Tiger and especially Brown Snake antivenom is substantially lower (10-20 times) than that predicted by CSL. These findings support an increase in the dose of antivenom to be used for the treatment of Tiger and especially Brown Snake envenomation complicated by coagulopathy. The in vitro canine model may be suitable for studying the procoagulant effects of Australian snake venoms.

Biochemical and neurotoxicological characterization of paradoxin, a β-neurotoxin from Australian inland taipan snake (Oxyuranus microlepidotus) venom

Biochemical and neurotoxicological characterization of paradoxin, a β-neurotoxin from Australian inland taipan snake (Oxyuranus microlepidotus) venom

Australian snake venoms and their in vitro effect on human platelets

Thrombocytopenia is generally not associated with cases of envenamation by Australian snakes, however the clinical evidence is conflicting. The in vitro effect of these venams upon platelets had hitherto not been studied. This study systematically examines the effect on human fresh and fixed platelets of twenty Australian snake venoms, nineteen elapid and an hydrophiid; for comparision four crotalid venoms from the Americas and S.E. Asia were also included. Electron micrographs were taken of platelets after exposure to some of the venoms. Results demonstrated that all venoms except the hydrophiid venom caused fresh platelets to irreversibly aggregate directly, and this was associated with degranulation as evidenced by electron microscopy(EM). Response to all venoms by fixed platelets was less marked and also suggests, that metabolically, active platelets are necessary for the venoms to exert their maximal effect. The hydrophiid venom's action on fresh platelets was unique, as a plasma co-factor was required before aggregation could be induced. Crotalid and hydrophiid venoms were more active against platelets than the elapid venoms. Nevertheless, platelet aggregation and degranulation in the presence of elapid venoms suggests that a platelet response in vitro may be a significant factor in the “defibrination syndrome” induced in humans by Australian snakes.

Immunological stability of an elapid venom, Tropidechis carinatus, and its relevance to the clinical detection of snake venom.

Using immunological techniques, cases of human snake-bite can be proven and individual snake species identified. A series of experiments is described, to test the antigenic stability and physical properties of an Elapid venom, venom properties which will have implications in field use, transport, or the laboratory procedures relating to the immunological characterization of Australian snake venoms. Using venom from the Elapid, Tropidechis carinatus, we have demonstrated significant immunological stability at a temperature of 37 degrees for 48 h at least, and for 24 h at least when incubated continuously with skin, muscle, and fat homogenates; the venom is stable at 56 degrees for 2 h at least. No loss of venom occurs over the pH range 7-10; at pH ranges less than 4 and at ranges greater than 10 only 30% of venom is detected after 30 min incubation. Sonication (10 min at 100 watts) does not destroy immunological properties of the venom; 10 freeze-thaw cycles result in some 9% loss of immunologically detectable activity. Venom is adsorbed significantly on to dacron swabs, only 13% of the applied does being detected after 48 h incubation at 28 degrees. Sixty-seven percent of applied venom can be recovered from the skin of human volunteers 6 h after a simulated bite. The venom of this Elapid is antigenically robust. With the currently available sensitive assays, venom from human skin should still be detected in material kept without special preparation under field conditions for up to 2 days at least.

Coagulant and Anticoagulant Actions of Australian Snake Venoms

A systematic study was made of the action on the plasma coagulation system of 20 Australian and Papuan Elapid and Hydrophiid snake venoms and compared with 4 Crotalid venoms and 1 Viper. The majority of Australian venoms were shown to be prothrombin activators with variable dependence on the presence of factor V phospholipid and calcium. None of these venoms had strong thrombin like activity in contrast to the Crotalid venoms which were powerfully thrombin like. The Crotalid venoms were also strongly fibrinolytic unlike the Elapid venoms which showed no or minimal evidence of fibrinolytic activity. Four Elapid venoms and 2 Crotalid venoms showed anticoagulant activity which contained neither antithrombin nor fibrinogenolytic activity and may act upon the prothrombin complex.

A study of the major australian snake venoms in the monkey (Macaca fascicularis): I. the movement of injected venom, methods which retard this movement, and the response to antivenoms

<h2>Summary</h2> Conscious monkeys were comfortably restrained for several hours whilst the movement and effects of injected snake venom was studied. Routine clinico-pathological studies were carried out on blood samples obtained at regular intervals and a solid phase radioimmunoassay was used to assay plasma levels of snake venoms and an individual neurotoxin. When snake venom was injected subcutaneously into the lower limb of a monkey and no first aid was applied, venom could be detected in the plasma of the animals within 15 min of the injection. Plasma venom and neurotoxin levels peaked about 60 min after the injection but signs of neurotoxicity were usually not seen until 120 min after injection. Post mortem studies showed that very little Tiger snake venom remained at the injection site, but high concentrations were found in the regional lymph nodes. Tiger snake venom components including the neurotoxin, notexin, were excreted in both the bile and urine of monkeys. The high levels of venom and neurotoxin found in the urine of monkeys parallel those found in some human snake bite victims. Recently developed first aid measures were applied to the envenomed limb of a number of monkeys. These measures consisted of the application of a firm crepe bandage to the length of the injected limb which was then immobilized with a splint. The first aid measures were found to delay the movement of all the major Australian land snake venoms and also the venom of the beaked sea snake (<i>Enhydrina schistosa</i>). A number of envenomed monkeys infused with antivenom immediately neurotoxic signs developed, barely survived even when given 10 times the amount of antivenom required to neutralize <i>in vitro</i> the dose of venom they had received. Surviving monkeys had persistent ptosis and lethargy for up to 5 d after envenoming. Failure to respond to antivenom was more likely if no effective first aid measure had been employed.

Toxicity of some Australian snake venoms for potential prey species of reptiles and amphibians

Venoms of five species of Australian elapid snakes were tested for lethal toxicity against 13 species of anurans and 21 species of lizards. Most anurans and geckos were quite susceptible to the venoms, lethal doses being 2.5 mg/kg or less. Some skinks were highly resistant to all venoms. Species of Ctenotus and Egernia survived doses of Notechis, Pseudonaja, and Acanthophis venoms in the range of 40–60 mg/kg, while mouse ld 50's for these venoms are less than 1 mg/kg. Instances of marked difference in resistance to venom were observed in closely related species of geckos and frogs. There is no evidence that venoms of these snakes are highly adapted to the snakes' preferred food and little evidence that the snakes rely heavily on venom in securing food. The mechanism responsible for the high immunity of some skinks to elapid venoms is unknown. It does not appear to depend on a serum factor.

A study of the major australian snake venoms in the monkey (Macaca fascicularis): II. Myolytic and haematological effects of venoms

Rhesus monkeys were kept in a restraining apparatus and while conscious injected with the venoms of a range of Australian snakes. Although the action of restraining itself caused an elevation of the animals' plasma creatine kinase (C.K.), the rise was up to 5 times greater in envenomed monkeys. The venoms of the Tiger snake, Mulga, Beaked Sea snake, Rough-Scaled, Copperhead and Red-Bellied snakes were all powerfully myolytic, and those of the Taipan and Small-Eyed snake less so. No myolytic activity was found in the venoms of the Common Brown snake and Death Adder, and the results with Dugite, Gwardar and Small-Scaled snake venom were equivocal. Significant coagulation disturbances were produced by all venoms studied except those of the Small-Eyed and Rough-Scaled snakes. When first aid measures were used, the coagulation disturbances which developed after the release of the injected venom were significantly less than when no first aid was used. This finding, which was observed with all snake venoms studied, suggests that the procoagulant factor may be subject to some inactivation whilst immobilized at the injection site.

PROCEEDINGS OF THE AUSTRALASIAN SOCIETY OF CLINICAL AND EXPERIMENTAL PHARMACOLOGISTS

PROCEEDINGS OF THE AUSTRALASIAN SOCIETY OF CLINICAL AND EXPERIMENTAL PHARMACOLOGISTS

Purification, from Australian elapid venoms, and properties of phospholipases A which cause myoglobinuria in mice

Ten Australian snake venoms ( Oxyuranus s. scutellatus, Notechis s. scutatus, N. ater serventyi, N. a. humphreysi, Acanthophis antarcticus, Austrelaps superba, Pseudonaja textilis, Pseudechis australis, P. porphyriacus, P. colletti) were fractionated by column chromatography on CM-Sephadex C-25 and the isolated fractions were tested in mice for ability to produce myoglobinuria after s. c. injection. Only venom fractions from A. superba, P. australis, P. porphyriacus and P. colletti produced this effect. Pure factors were obtained from the latter three venoms and shown to be neutral or basic phospholipases A containing 120–129 amino acid residues (formula wts between 13,400 and 14,200). The enzymes have acute LD 50 values (s.c. injection) of 4·3–7·7 mg/kg, however, the minimum doses necessary to produce myoglobinuria in mice are between 0·5 and 5·0 mg/kg. These venom components affecting skeletal muscle may play an important role in snakebite.

Changes in antigenic character of fresh Australian snake venom upon aging

Fresh Australian snake venom of Pseudechis porphyriacus, Demansia textilis, Denisonia superba, Acanthophis antarcticus, Oxyuranus scutellatus and Notechis scutatus did not cross react with antivenin except almost negligibly in the case of Acanthophis antarcticus antivenin for Demansia textilis and Denisonia superba. On standing for 2–3 months the dried venom acquired cross-reactions, the significance of which is discussed.

Changes in antigenic character of fresh Australian snake venom upon aging: E. R. Trethewie (Department of Physiology, University of Melbourne, Parkville, Victoria 3052, Australia) and Laila Khaled (The University of Cairo, United Arab Republic), Toxicon, 1973, 11, 55

Changes in antigenic character of fresh Australian snake venom upon aging: E. R. Trethewie (Department of Physiology, University of Melbourne, Parkville, Victoria 3052, Australia) and Laila Khaled (The University of Cairo, United Arab Republic), Toxicon, 1973, 11, 55

The coagulation defect produced in three patients following the bite of the dugite (Demansia Nuchalis Affinis)

The venoms of most Australian elapid snakes contain substances which clot mammalian blood. In vitro, such venoms have been found to activate human prothrombin. The effects of envenomation on blood coagulation and haemostasis might therefore be expected to resemble those of disseminated intravascular coagulation. In 3 patients bitten by dugites, there were similar coagulation defects: clottable fibrinogen was absent, fibrinogen degradation products were found, prothrombin times were greatly prolonged and levels of factors II, V and VIII were reduced. Platelet counts were, however, normal. After administration of antivenene, these abnormalities were corrected within a few days. No patient had overt bleeding. Severe thrombocytopenia is a characteristic feature of 'endogenous' disseminated intravascular coagulation, but was not seen in these patients. There was also evidence of extensive lysis of circulating fibrinogen in all cases. These findings suggested that the 'thrombin' produced by the venom activation may not be identical with that produced by physiological prothrombin activation.

Paraspecific protection by elapid and sea snake antivenins

Seventeen elapid antivenins and one sea snake antivenin were tested for neutralizing activity against a panel of fifteen elapid venom samples (eight Naja, three Bungarus, one each of Ophiophagus, Hemachatus, Walterinnesia and Micrurus) and one sea snake ( Enhydrina) sample. Assays were made by injecting mice subcutaneously with 2–10 ld 50 of venom and injecting antivenin intravenously immediately thereafter. Antivenins against venoms of certain Australian snakes (tiger snake, death adder, taipan) protected animals against at least fifteen of the venoms used. Tiger Snake Antivenene neutralized ten of the venoms at a dose of 10 ld 50. Sea Snake Antivenene showed at least some protective effect against fourteen of the fifteen elapid venoms used, but most elapid antivenins failed to neutralize sea snake venom. Cobra antivenins proved largely genus specific and showed considerable variation in neutralizing capacity. Venoms of Naja n. atra and N. nigricollis were less well neutralized than other cobra venoms. Krait antivenins were relatively ineffective even in homologous systems. Coral snake ( Micrurus fulvius) venom proved very difficult to neutralize. Certain implications of these findings are discussed and suggestions made for utilizing the paraspecific effect of elapid antivenins in clinical situations.

Haemolysins in venoms of Australian snakes. Observations on the haemolysins of the venoms of some Australian snakes and the separation of phospholipase A from the venom of Pseudechis porphyriacus.

Haemolysins in venoms of Australian snakes. Observations on the haemolysins of the venoms of some Australian snakes and the separation of phospholipase A from the venom of Pseudechis porphyriacus.

Purine compounds in snake venoms.

Fischer and Dorfel1 identified adenosine in the venom of Bitis arietans and Dendraspis viridis in concentrations of 12 and 2.6 per cent of the dry weight respectively, and concluded it was a natural component of the fresh venom. In the venoms examined no other nucleoside was found; nucleotides were absent but traces of a guanine compound were not excluded. The present communication reports the identification and estimation of adenosine 3′-phosphate in addition to adenosine in some species of Australian snake venoms.

A New Method of Determining Plasma Fibrin

The usual method of estimating the fibrinogen content of the blood is by recalcifying the oxalated plasma in order to convert the fibrinogen into fibrin. The quantity of fibrin precipitated is then determined by the Kjeldahl, the gravimetric, the colorimetric, or the refractometric methods. The method of determining plasma fibrin presented here is based on the coagulant activity of certain types of snake venom. Martin was the first to demonstrate the striking activity of the venoms of certain Australian snakes in causing coagulation of blood both in vivo and in vitro. Lamb found that minute doses of such venoms could also coagulate in vitro blood which had lost the capacity for spontaneous coagulation on account of the addition of citrates, oxalates or fluorides. Among the venoms noted for their coagulating action are those of the following snakes: Notechis scutatis (tiger snake), Pseudechis porphyriacus (black snake), Echis carinata (phoorsa) and Viperi russelli (daboia). The former 2 species are found in Australia and the latter 2 in India. In addition, certain species of the Lachesis group of vipers are known to exhibit this property. In the present investigation, tiger snake venom, which apparently has the most powerful coagulating action, was used. In all probability, the venoms of the other species mentioned can also be used. The actual technique of estimating the concentration of fibrinogen (as fibrin) in the plasma with the aid of tiger snake venom is as follows: One cc. of oxalated plasma is diluted 25 to 30 times with normal saline solution. (The quantity of powdered potassium oxalate used for collecting the blood need not be accurately measured.) To the diluted plasma is added 0.3 cc. of a 1 to 5,000 dilution of dried tiger snake venom in normal saline.

Some peculiarities of australian snake venoms

The Australian colubrid snakes present a gradual transition in morphological characters towards the viperine type. There is no similar regular transition in the venoms, though these exhibit certain points of difference from the venoms of other colubrid snakes. Viperine venoms are not so toxic as those of the colubridæ. They possess powerful thrombins, but usually kill by causing peripheral circulatory failure, which is contributed to by cytolysis of vascular endothelium. They are weak in hæmolytic and curari-like action. The venoms of the colubridæ generally possess no thrombins, but contain powerful hæmolysins and are predominantly curari-like poisons. Some have an additional direct action on muscle. They cause death by paralysis of respiration, but this is a peripheral and not a central action. Some of the Australian venoms are powerfully coagulant. Hæmorrhagins are not strongly represented. Their hæmolysins, though generally similar in action to those of other colubrid venoms, exhibit certain points of difference. They are not influenced by the presence of complement. Serum frequently inhibits instead of activating hæmolysis. The hæmolysins, though they cause inhibition of hæmolysis when present in excess, do not render the cells less susceptible to other lytic agents. The Australian venoms are peculiarly toxic when administered subcutaneously and though this is in part due to their curari-like action it cannot so be wholly accounted for. There is no convincing evidence of direct action on the central nervous system and their extreme toxicity may be due also in part to action on the peripheral circulation. On smooth muscle the Australian venoms exhibit a wholly peculiar action, which resembles the anaphylactic response of sensitive plain muscle. Similar effects can be demonstrated upon the isolated uterine muscle and upon the intact vascular system. The potency of this action on smooth muscle is closely paralleled by the lethal action of the venoms when injected subcutaneously in laboratory animals.

THE FRACTIONATION OF AUSTRALIAN SNAKE VENOMS

Australian Journal of Experimental Biology and Medical ScienceVolume 6, Issue 4 p. 245-260 Original Article THE FRACTIONATION OF AUSTRALIAN SNAKE VENOMS† I. THE VENOM OF THE DEATH ADDER (ACANTHOPHIS ANTARCTICUS) CH Kellaway, CH Kellaway Walter and Eliza Hall Institute, MelbourneSearch for more papers by this authorMavis Freeman, Mavis Freeman Walter and Eliza Hall Institute, MelbourneSearch for more papers by this authorF Eleanor Williams, F Eleanor Williams Walter and Eliza Hall Institute, MelbourneSearch for more papers by this author CH Kellaway, CH Kellaway Walter and Eliza Hall Institute, MelbourneSearch for more papers by this authorMavis Freeman, Mavis Freeman Walter and Eliza Hall Institute, MelbourneSearch for more papers by this authorF Eleanor Williams, F Eleanor Williams Walter and Eliza Hall Institute, MelbourneSearch for more papers by this author First published: 01 December 1929 https://doi.org/10.1038/icb.1929.24Citations: 5 † This research was carried out under a grant from the Department of Health of the Commonwealth of Australia. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume6, Issue4December 1929Pages 245-260 Journal of the Australian and New Zealand Society for Immunology RelatedInformation