Findlay E. Russell

Snakes and snakebite in Central America

This review treats the general biology, taxonomy, distribution and venom apparatus of the venomous snakes of Central America. Consideration has been given to the chemistry, pharmacology and immunology of the venom, and particular attention is dispensed to the clinical problem, including the treatment, of envenomations by these reptiles.

Snake Venom Immunology: Historical and Practical Considerations

AbstractMan has tried to immunize himself against snake venoms and other poisons since the beginnings of history. The scientific study of antivenins began with the work of Henry Sewall in 1887 and has progressed through the present century. Currently, a large number and diversity of monovalent and polyvalent antivenin preparations produced by well-defined protocols are commercially available around the world. These preparations owe much to the pioneering studies of many research workers, but most notably to the work of Sewall, Calmette, Fraser, Brazil, and Noguchi, and more recently to the studies of Boquet and Minton.

Preliminary studies on the venom of the colubrid snake Rhabdophis subminatus (red-necked keelback)

Following the bite by Rhabdophis subminatus, preliminary studies were instituted on its venom to determine the mechanism of the clinical poisoning. A method for milking these snakes is presented. The i.v. LD50 in mice was 1.29 mg/kg. Three peaks were obtained on Sephadex G-100 and although none were lethal by themselves, a combination of two of the peaks produced immediate death in mice. The venom had no phosphodiesterase, fibrinolytic or thrombin-like activities, but it did have some phospholipase activity. Further biochemical and pharmacological studies are in progress.

Ciguateric Fishes, Ciguatoxin (CTX) and Ciguatera Poisoning

AbstractCiguatera poisoning is caused by the eating of certain tropical and semi-pelagic marine fishes or by a few species of gastropods. In the case of the fishes, these have fed upon either carnivorous or benthonic algal feeders, which have accumulated the toxin through the food chain. The basic organisms involved are dinoflagellates, principally Gambierdiscus toxicus. The toxin, ciguatera toxin (CTX) is C55H76O18 and appears to favor a rather selective choice in voltage - dependent Na+ channels in nerve and muscle cells, and in synaptic terminals. In this respect, the channel(s) are different from those so far identified for tetrodotoxin, maitotoxin, and the other marine toxins for which specific channels have been implicated.Although the poisoning has been known for over 200 years, it has been during only most recent years that it has become a public health problem. While most cases occur in the Pacific Ocean and Carribean Sea, the poisoning is now been reported from numerous parts of the world, and w...

Isolation by preparative isoelectric focusing of a direct acting fibrinolytic enzyme from the venom of Agkistrodon contortrix contortrix (southern copperhead)

Fibrolase, a blood clot-lysing enzyme, was isolated from the venom of the snake Agkistrodon contortrix contortrix using preparative scale isoelectric focusing in the recycling isoelectric focusing (RIEF) apparatus. Two sequential purifications, beginning with 1.0 g of whole, dried venom, were employed. A pH 6-8 range gradient effected the first separation. While 100% of the enzyme was recovered in three fractions, 43% (one fraction) had 70% purity. The second run was a refractionation of three, pooled fractions from the first run, in a 0.7 pH range gradient. Of the fibrolase in the venom, 63% was recovered in four fractions. One of these represented 29% of venom fibrolase, with 97% purity. Gel filtration chromatography removed most of the remaining, higher molecular weight contaminants of the RIEF-purified enzyme.

The action of equinatoxin, a peptide from the venom of the sea anemone, Actinia equina, on the isolated lung

On perfusion through isolated lungs from male Sprague-Dawley rats, equinatoxin caused a dose-dependent increase in the wet to dry weight ratio. Ratios were significantly elevated above control values at equinatoxin concentrations of 80-200 ng/ml. The increased ratios were accompanied by an increase in the permeability of the lung vasculature. When equinatoxin was perfused through isolated lungs at concentrations of 100 ng/ml or greater, significantly more [3H]polyethylene glycol (PEG; approximately 900 mol. wt) was retained in the extravascular space as compared to controls. Perfusion pressures of the lung were significantly elevated above controls at equinatoxin concentrations greater than 100 ng/ml. These effects of equinatoxin were not mediated by degranulation of mast cells, as preperfusion of the lung with 100 or 200 microM Na cromolyn or 1 microM lanthanum chloride did not modify the pulmonary response to equinatoxin. At concentrations of equinatoxin below 150 ng/ml the fluid movement appears to be restricted primarily to intracellular, or possibly interstitial, spaces, as no significant amounts of [3H]polyethylene glycol were recovered by tracheal lavage. At concentrations of equinatoxin equal to or greater than 150 ng/ml, significant amounts of PEG were washed from the trachea. As it is a potent inducer of pulmonary edema, equinatoxin may become an important probe to study fluid regulation in the lung.

Effects of preparatory procedures on the venom from a rattlesnake (Crotalus molossus molossus), as determined by isoelectric focusing

A study was made on the venom of a single specimen of the rattlesnake Crotalus molossus molossus, utilizing isoelectric focusing in polyacrylamide gels, to determine what effects various commonly employed preparative procedures might have on the chemical properties of the venom. The procedures included storage at several temperatures, freezing and thawing, evaporation, desiccation and lyophilization. Results indicated that the numbers and relative positions of the protein bands were constant with each procedure. It was concluded that the various procedures did not cause enzymatic degradation or major shifts in the pI of the bands. The significance of the findings is discussed.

Introduction of the scorpion Centruroides exilicauda into California and its public health significance

The bark scorpion, Centruroides exilicauda, formerly C. sculpturatus, is a native of Arizona and adjacent parts of New Mexico in the United States, and Baja California and Sonora in Mexico. A few specimens have been captured on the California side of the Colorado River. The general biology of this scorpion is discussed and the introduction of the arthropod into three California counties, probably in trailer paraphernalia and dune buggies, is described. Four probable stings by C. exilicauda in California and their public health significance are presented.

Intravenous dose-lethality study of American pit viper venoms in mice using standardized methods

An intravenous dose-lethality study of 14 clinically important North and South American pit viper venoms was carried out in mice using standardized, rigorous protocols developed to meet international (WHO) guidelines and US government (FDA) regulations for the development of new treatment products. The study was undertaken in order to establish baseline LD 50 values for the ongoing testing of a new crotalid antivenin F AB prepared from sheep immunoglobulin (IgG). The venoms (lyophilized and pooled from juvenile and adult snakes of both sexes) were taken from 10 rattlesnake (nine Crotalus and one Sistrurus) species, two Agkistrodon species, and two Bothrops species. The dose-response data were subjected to probit analysis. Median lethal dose (LD 50 ) values and their 95% confidence limits (CL) were calculated and statistical comparisons between the median potencies were made. The intravenous LD 50 s (and 95% CL) ranged from a low of 0.13 (0.10–0.15) mg kg –1 for Crotalus durissus terrificus , to a high of 6.32 (5.76–6.94) mg kg –1 for Crotalus horridus horridus . Significant positive rank-order correlations were also found for comparisons between the present LD 5O s and published LD 5O s for intravenous, intraperitoneal, and subcutaneous administration.

The effect of an electrical current on snake venom toxicity

An electric current (twenty 11 A, 7000V spikes s −1 for 90s) from a commercial stun gun was applied directly to a rattlesnake venom solution in an electrolysis cell with 2 electrode compartments and a central compartment, in order to evaluate the effect that high voltage electroshock might have on the lethality of the venom. The venom was electroshocked for 18 times longer than recommended by stun gun manufacturers. There was no measurable inactivation of the venom using LD 50 determinations in mice. A venom sample was electrolyzed at a voltage lower than that from the stun gun, but with 4–5 times the total charge delivered from the stun gun. This inactivated the venom at the electrodes, but not within the central compartment, demonstrating that there was no direct effect of the electric field on the activity of the snake venom.