404 THE BIOCHEMISTRY OF B VITAMINS 



tolerance). In human beriberi, too, some degree of hyperglycemia is 

 common. It is noteworthy in this regard that both the islets of Langerhans 

 and the adrenal medulla are frequently hypertrophied in beriberi. It has 

 also been observed that there is a decrease in gastric acidity in beriberi, 

 frequently progressing to achlorhydria, and Goodhart and Sinclair 56 

 have demonstrated a definite correlation between gastric acidity and blood 

 cocarboxylase. Mention should be made of the evidence that milk from 

 women suffering from beriberi contains a toxic factor, as do the blood, 

 urine and tissues of thiamine-deficient experimental animals, and that 

 such toxic factors may be in part responsible for some of the deficiency 

 symptoms. 57 Methylglyoxal has been suggested in this regard, although 

 there is insufficient evidence available to evaluate properly the numerous 

 papers dealing with the presence of this substance in thiamine-deficient 

 animals. 



Horwitt 58 has recently given considerable attention to the study of 

 blood lactate and pyruvate in mild thiamine deficiency and has concluded 

 that the basal levels are of little diagnostic value, since at this stage the 

 organism can still retain a blood equilibrium. Only after pronounced 

 clinical signs of deficiency become apparent do the blood levels change, 

 and even then exceptions occur. During mild deficiency, lactate and 

 pyruvate determination following glucose administration are significant 

 if correlated with the blood glucose. It was further found in this study 

 that mild exercise after glucose administration made it readily possible 

 to detect distinct characteristics in mild thiamine deficiency at an early 

 stage in its development. A formula termed the "Index of Carbohydrate 

 Metabolism" or "(CI)" was developed to relate the amounts of blood 

 lactate (L), pyruvate (P), and glucose (G) in milligrams per cent, and 

 a change in this index seemed to be highly indicative of thiamine restric- 

 tion. 



(CI) 



0-3+( i5p -3 



Patients receiving 200 /xg of thiamine per day showed increases of 

 this index to a pathological level within 10 weeks or less, and clinical 

 signs of deficiency followed within one to four months after the first 

 significant rise. This study merits particular attention from the student 

 of thiamine nutrition because of its extended nature (three years), its 

 coordinated approach involving biochemical, clinical, neurological, and 

 psychological investigations, its carefully controlled nature, and the 

 tremendous emphasis placed on the study and reporting of individual data 

 rather than average data. While it was primarily concerned with the 



