Effect of Heparin upon Various Forms of the Thrombohemorrhagic Phenomenon (THP)

In rats, a thrombohemorrhagic phenomenon (THP) can be elicited by the intravenous injection of various metal combinations, especially if these are given in conjunction with norepinephrine. The syndrome is characterized by multiple hemorrhages and microthromboses located mainly in the kidneys, duodenum, heart and lung. In addition, severe and sometimes necrotizing thrombohemorrhagic lesions are observed at the site of catecholamine injection. Intravenous administration of agar elicits essentially the same internal changes even without the concurrent administration of norepinephrine.

An anaphylactoid form of the THP is induced by agar plus dextran or egg white. Here, the usual internal lesions are associated with thrombohemorrhagic changes in the anaphylactoid shock organs, especially the paws, snout and the root of the tail.

All these forms of the THP are inhibited by pretreatment with heparin.