Abstract
It has been found that p-aminohenzoic acid prevents the inhibitory action of sulfanilamide on the growth of hemolytic streptococci in vitro 1 2 and in vivo. 3 This compound also inhibits the therapeutic effect of sulfanilamide on mice inoculated intracerebrally with the virus of lymphogranuloma venereum. 4 It has been suggested 2 3 4 that sulfanilamide exerts its action by competing for an enzyme associated with a metabolite similar in structure to p-aminobenzoic acid and essential to the organism.
Coggeshall 5 showed that sulfanilamide had a marked effect against plasmodia (Plasmodium knowlesi in rhesus monkeys). Other sulfonamides 6 were shown to be effective against P. knowlesi and against Plasmodium cynomolgi and Plasmodium inui in rhesus monkeys. Sulfadiazine was shown 7 to be effective against human malaria (Plasmodium vivax and Plasmodium falciparum). The present paper reports the effect of p-aminobenzoic acid in inhibiting the action of sulfanilamide against plasmodia.
Plasmodium gallinaceum was used as the test infection in Leghorn or Rhode Island Red chicks weighing 50-100 g. Five birds were used for each test and 10 for each control group. The drugs used were mixed with a powdered chick mash so that the stated daily dose of drug was contained in 10 g of mash. This amount of drug-food mixture was consumed over a 24-hour period. Blood concentrations of sulfanilamide, determined by the method of Marshall and Litchfield 8 with a photoelectric colorimeter, were shown to be maintained at a uniform level over a 24-hour period by this method of administration. Drug feeding was continued for 10 days with blood level determinations on the 2nd and 3rd days.
Get full access to this article
View all access options for this article.