Toxicon : official journal of the International Society on Toxinology
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The effect of stimulation frequency on the timecourse of neuromuscular blockade, following the administration of textilotoxin (20 micrograms/kg) or beta-bungarotoxin (50 micrograms/kg), was examined in the interdigital muscles of the hindlimb in anaesthetized mice. While the time of death was variable, neuromuscular blockade of the interdigital muscles occurred at the same time as respiratory failure with both textilotoxin and beta-bungarotoxin only at stimulation rates of 0.5 Hz and above. Textilotoxin (50 micrograms/kg) produced an increase in the heart rate prior to death but no change in the shape of the electrocardiogram.
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The documented case of a human fatality resulting from envenomation by Physalia physalis is presented. Although this case is only the second scientifically recorded fatality, several similar cases have been suspected.
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A near fatal case of ciguatera-related intoxication following consumption of smoked Decapterus macrosoma is documented. In addition to some of the hallmark symptoms of ciguatera poisoning, the patient exhibited acute respiratory distress and severe muscle spasms. Laboratory results showed large elevations in a number of blood enzymes, indicative of muscle damage. The responsible agent was extracted from corresponding fish samples and identified as palytoxin.
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Review
Venomous pelagic coelenterates: chemistry, toxicology, immunology and treatment of their stings.
Ten years have elapsed since our last review article on the toxicology of venomous pelagic coelenterates was published (Burnett and Calton, 1977). Investigation on important medusae and the chemistry of their nematocyst venoms have been expanding. The venomous jellyfish discussed here include the Portuguese man-o'war, (Physalia physalis), the sea nettle (Chrysaora quinquecirrha), the box jellyfish (Chironex fleckeri and/or Chiropsalmus quadrigatus), the cabbage head jellyfish (Stomolophus meleagris), the lion's mane jellyfish (Cyanea capillata), the Irukandji jellyfish (Carukia barnesi), the Moreton Bay Carybdeid medusa (Morbakka), and the mauve blubber (Pelagia noctiluca).
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Studies were conducted with isolated segments of pulmonary artery to characterize vessel contractility in monocrotaline-induced pulmonary hypertension. Contractions of pulmonary artery segments from rats given monocrotaline in drinking water (20 mg/l) for up to 20 days were measured in tissue baths. Dose response curves were produced with norepinephrine or serotonin and the response to 120 mM potassium chloride (KCl) was measured. ⋯ In separate experiments using continuous exposure to monocrotaline, a minimum of 15 days treatment was required before contractile activity was significantly altered. Results indicate monocrotaline treatment reduces the contractile activity of muscular pulmonary artery. Alterations in vessel responsiveness were produced after a minimum of 4 days treatment with monocrotaline in drinking water (an estimated exposure of 14-20 mg/kg) but required 15-20 days to develop.