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Biomedical subjects

S K Sutherland

Publications and source records attributed to S K Sutherland.

At least 19 recordsLinked to original sources

Pharmacological studies of jumper ant (Myrmecia pilosula) venom: evidence for the presence of histamine, and haemolytic and eicosanoid-releasing factors.

Jumper ant venom was prepared by extraction of venom sacs in distilled water and centrifugation to remove insoluble material. Jumper ant venom (2 micrograms/ml) produced a biphasic response on isolated guinea-pig ileum, i.e. an initial rapid contraction followed by a slower prolonged contraction. The histamine antagonist mepyramine (0.1 microM) inhibited the first phase of this response by greater than 90%. In the isolated rat stomach fundus strip (which is insensitive to histamine), jumper ant venom (6 micrograms/ml) produced only a single contraction. No tachyphylaxis was observed to repeated doses of jumper ant venom in guinea-pig ileum or rat fundus strip. Responses to jumper ant venom of the egg-albumin-sensitised guinea-pig ileum were not significantly different before and after an in vitro anaphylactic response induced by egg albumin (0.5 mg/ml). Fluorometric assay revealed a mean value of 0.9 +/- 0.2% of the dry weight as histamine in jumper ant venom. Both the lipoxygenase/cyclo-oxygenase inhibitor BW755C and the cyclooxygenase inhibitor indomethacin significantly inhibited the second phase response to jumper ant venom of the guinea-pig ileum, and the response of the rat fundus strip. The muscarinic receptor antagonist atropine (0.1 microM), the bradykinin antagonist [Thi5,8,D-Phe7]-bradykinin (10 microM) and the angiotensin converting enzyme inhibitor captopril (20 microM) did not affect either phase of the venom response in guinea-pig ileum. Jumper ant venom caused haemolysis of guinea-pig blood. The degree of haemolysis was significantly reduced when boiled venom was used. These results suggest that jumper ant venom contains histamine and may cause the release of cyclo-oxygenase products. It also contains a heat-sensitive haemolytic factor.

4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyraz

Rationalisation of first-aid measures for elapid snakebite.

The plasma of monkeys envenomated with tiger snake (Notechis scutatus) venom was monitored by radioimmunoassay for both crude venom and a neurotoxin. When the injected limb was immobilised and a pressure of 55 mm Hg applied to the injection site, only very low levels of circulating venom or neurotoxin were detectable. In practical terms, venom movement can be effectively delayed for long periods by the application of a firm crepe bandage to the length of the bitten limb combined with immobilisation by a splint. Pressure alone or immobilisation alone did not delay venom movement.

Animals

Survey of 2144 cases of red-back spider bites: Australia and New Zealand, 1963--1976.

An analysis has been made of 2144 consecutive cases of latrodectism (envenomation by the red-back spider, Latrodectus mactans hasselti) reported to the Commonwealth Serum Laboratories. In the last eight years, notifications have averaged 240 cases per annum. Bites, usually on the extremities (74%), occurred most frequently in the summer months, and in the afternoon or evening. Most victims (79%) were aged between 18 and 50 years and 64.4% of them were males. Males are still often bitten on the genitals or buttocks (9.7% of cases). Local pain, redness and swelling were the most common symptoms, although significant pain was felt at other sites in 39% of the cases. The regional lymph nodes often became swollen and tender within 30 minutes. General effects included nausea, vomiting and sweating, but coma and respiratory failure were very uncommon, probably because of use of specific antivenom. This was administered within 24 hours of the bite in 92% of cases, and within two hours in 70%. Although 11 anaphylactic reactions (0.54%) were reported, no deaths resulted either from the venom or from reactions to the antivenom. Few delayed serum reactions (1.7%) were recorded. The action of the venom is described and the management of red-back spider bite is outlined.

Adolescent

Australia's potentially most venomous snake: Parademansia microlepidotus.

Studies on the venom of the small-scaled or fierce snake, Parademansia microlepidotus, suggested that its combination of high toxicity and relatively large venom yield make it the most venomous snake in Australia. The species is distinct from the taipan, but its venom is neutralized by taipan antivenom but not other monospecific antivenoms.

Antivenins