208 PTEROYLGLUTAMIC ACID 



McPherson and associates^^^ and Sturgeon and Carpenter^^^ have reported 

 good remissions after administration of B12 , although the latter authors 

 obtained only "equivocal responses" in two of. their five cases. There have 

 been no instances reported of failure of response to PGA after adequate 

 trial. 



The existence of a relationship between lack of ascorbic acid and megalo- 

 blastic anemia of infancy^^^ receives support from the observation of the 

 role of this vitamin in the conversion of PGA to CF,'*^ from the occurrence 

 of megaloblastic anemia in scorbutic and PGA-deficient monkeys,'*"*"^^® and 

 from the apparent decrease in incidence of megaloblastic anemia in infancy 

 after the addition of ascorbic acid to a popular brand of processed milk 

 food. However, unqualified application of the findings of in vitro studies 

 and animal experiments to the problem of infantile megaloblastic anemia 

 is unjustifiable, and moreover it has not been shown that CF is more 

 efi"ective than PGA in the treatment of this form of anemia in humans. 

 In the present state of our knowledge, it must be concluded that dietary 

 lack of PGA, vitamin B12 , or ascorbic acid may play a role in the develop- 

 ment of megaloblastic anemia of infancy and that it is probable that most 

 cases are due to a combination of these deficiencies. In any event, PGA 

 appears to be completely efficacious in the treatment of this form of megalo- 

 blastic anemia. 



5. Sprue and Idiopathic Steatorrhea 



These conditions are considered together, since the biochemical defects 

 are indistinguishable although etiologic factors are undoubtedly different. 

 In the so-called tropical sprue which was formerly endemic in the southern 

 part of the United States and parts of Latin America, malnutrition was 

 almost invariably the rule. Tropical sprue as described by British authors 

 commonly affects European residents in the tropics and is attributed to a 

 peculiar environmental effect. Non-tropical sprue or idiopathic steatorrhea 

 is a sporadic disease of unknown etiology in which there is generally no 

 history of dietary abnormality or unusual environment. Megaloblastic 

 anemia is of common occurrence in each of these related conditions, but 

 the factors responsible for its development may be presumed to ^•ary and 

 the effects of therapy are known to differ, at least in degree. 



Soon after synthetic PGA became available, its effectiveness was demon - 



'81 A. Z. McPherson, U. Jonssoii, and R. W. Rundles, ./. Pvdial. 34, 529 (1949). 



'82 P. Sturgeon and G. Carpenter, Blood 5, 458 (1950). 



'83 C. A. Nichol and A. D. Welch, Proc. Soc. Exptl. Biol. Med. 74, 52 (1950). 



'8' CD. May, E. N. Nelson, C. U. Lowe, and P. J. Salmon, Ani. ./. Diseases Children 



80, 191 (1950). 

 '85 C. D. May, E. N. Nelson, R. J. Salmon, C. L'. Lowe, P. I. Lienke, and R. D. 



Sundberg, Bull. Univ. Minn. Hosp & Minn. Med. Found. 21, 208 (1950). 

 '85 C. D. May, R. D. Sundberg, and F. Schaar, /. Lab. Clin. Med. 36, 963 (1950). 



