Atypical pulmonary thrombosis caused by a toxic cyanobacterial peptide.

Parenteral injection into mice of a toxic pentapeptide isolated from the cyanobacterium Microcystis aeruginosa induced thrombocytopenia, pulmonary thrombi, and hepatic congestion. The lethality of the toxin was unaffected by several anticoagulants. The acute liver damage that follows injection of the toxin has been attributed to direct action on liver cells but may be due to hypoxemia, heart failure, and shock.