^-AMINOBENZOIC ACID 



on the organisms of lymphogranuloma venereum or psittacosis.^^ 

 ^-Aminobenzoic acid had an anti-rickettsial activity in the guinea-pig 

 in a dose of 0-3 g. per 100 g. of diet ^^ and has been tried out with 

 considerable success in rickettsial infections in man.^^ Thus in twenty 

 cases of louse-borne typhus, an initial dose of 4 to 8 g. of ^-amino- 

 benzoic acid was given, followed by 2 g. every two hours ; this main- 

 tained a blood concentration of between 10 and 20 mg. per 100 ml. 

 The symptoms were less severe in the treated patients than in the 

 untreated controls, and the duration of the fever was considerably 

 shorter. Similar beneficial results were obtained in twenty-nine 

 patients with endemic (murine) typhus and in eighteen patients with 

 tsutsugamushi disease. A large number of cases of Rocky Mountain 

 spotted fever have been successfully treated with _/)-aminobenzoic 

 acid, which is now regarded as the drug of choice. The dose for 

 children is 0-9 g. per kg. of bodyweight.^^ 



The chemotherapeutic activity of. sulphadiazine on psittacosis 

 virus was antagonised competitively by ^-aminobenzoic acid and non- 

 competitively by pteroylglutamic acid, suggesting that the sulphon- 

 amide exerted its effect by interfering with the incorporation of 

 _/)-aminobenzoic acid into pteroylglutamic acid by the virus. ^'^ p- 

 Aminobenzoic acid also reversed the action of sulphadiazine on the 

 viruses of mouse pneumonitis and lymphogranuloma venereum. ^^ 



References to Section 9 



1. S. D. Rubbo and J. M. Gillespie, Nature, 1940, 146, 838 ; Lancet, 



1942. 1, 36. 



2. R. Kuhn and K. Schwartz, Ber., 1941, 74B, 1617. 



3. M. Landy and D. M. Dicken, /. Biol. Chem., 1942, 146, 109. 



4. J. C. Lewis, ibid., 441. 



5. J. O. Lampen and W. H. Peterson, Arch. Biochem., 1943. 2, 



443- 



6. B. T. Bernstein and H. A. Barker, /. Bact., 1948, 55, 222. 



7. E. E. Snell and H. K. Mitchell, Arch. Biochem., 1942, 1, 93. 



8. J. O. Lampen, R. R. Roepke and M. J. Jones, /. Biol. Chem., 



1946, 164, 789. 



9. M. Landy, N. W. Larkum and E. J. Oswald, Proc. Soc. Exp. Biol. 



Med., 1943, 52, 338. 



10. R. D. Housewright and S. A. Koser, /. Infect. Dis., 1944, 75, 



113- 



11. M. Landy, N. W. Larkum, E. J. Oswald and E. Streightoff, Science, 



1943, 97, 295. 



12. H. Mcllwain, Biochem. J., 1945, 39, 329. 



13. H. Mcllwain, Nature, 1946, 158, 898. 



13a. J. O. Lampen, M. J. Jones and R. R. Roepke, /. Biol. Chem., 

 1949, 180, 423. 



558 



