340 ANIMAL BIOCHEMISTRY 



connection between the metabolic functions of the vitamin and the 

 appearance of the characteristic symptoms is not known. 



Pellagra is Hmited primarily to the lowest economic groups in areas 

 where cornmeal is a staple food. It has been most serious in the south- 

 ern parts of the United States and Italy and in Egypt. In Mexico a 

 similar wide use of corn is not a predisposing factor because of the 

 alkali treatment in the processing method employed there. In the 

 United States in 1917, 170,000 cases of pellagra were reported, and 

 many mild cases were undoubtedly never diagnosed. Even by 1927 

 there were still over 120,000 cases, with more than 21,000 known deaths 

 in 1928 to 1930. From 1911 to 1916 there were more deaths from 

 pellagra than from tuberculosis or malaria, the leading infectious 

 diseases. Incredible as it may seem, over 600 deaths were attributed 

 to pellagra in 1948, in a period of great national prosperity and 

 general economic well-being. It is encouraging that the death rate 

 is declining rapidly. 



Most American cases are due to diets consisting mainly of cornmeal, 

 salt pork, and molasses with an insufficiency of the meat. The disease 

 is associated with insanity as both a cause and a result. In some 

 countries pellagra is common among prisoners given very poor 

 food. Occasionally it appears in individuals with good diets but with 

 poor absorption of the vitamin. Chronic alcoholism also produces 

 some fatal cases. 



VITAMIN Bo 



Chemistry 



This essential factor turned up in connection with studies on pel- 

 lagra, where it sometimes occurs as a part of that multiple deficiency. 

 Although microorganisms may be specific for the chemical form of the 

 vitamin they can utilize, animals thrive on any one of four derivatives. 



CH2OH 



CH2NH2 



CHO 



H0/^%CH20H HO^^CH.OH H0,.^^S^GH20H 



CH. 



■N 



^ 



pyridoxine 



pyridoxamine 



CHO 

 I 

 HO^.^%^_CH20P03= 



CHakj^^ 



pyridoxalphosphate 



CH; 



pyridoxal 



