X. EFFECTS OF DEFICIENCY 4G1 



thiamine deficiency Swank ami Prados' made the ol)servation that the 

 first neuri)iial histolof^ic change in thiamine-defi<'ient pigeons is degeneration 

 of tlie distal part of the axon, and changes in myelin are secondary to this, 

 and further that opisthotonus (the characteristic manifestation of acute 

 thiamine deficiency in pigeons) may not he attended by any definite neuro- 

 logic lesions. 



About thirty years after the work of Eykman, Peters in Oxford, England, 

 was al)le to demonstrate that not only the peripheral nerves, but also the 

 central nervous system was affected by a thiamine deficiency. From that 

 work of Peters resulted a large part of our knowledge of the role thiamine 

 plays in carbohydrate, especially in pyruvate, metabolism. It is probable 

 that most of the pathology of thiamine deficiency is due to a disturbance 

 in the carbohydrate metabolism. The comprehensive work of Peters and 

 his school on the details of the biochemical action of substances causing 

 pathological effects and in particular in trying to understand the initial 

 changes from thiamine deficiency has led him to call these initial changes 

 "biochemical lesions."- Peters studied the epistothonus signs induced in the 

 rice-fed pigeon by thiamine deficiency. The epistothonus signs clear up very 

 quickly when thiamine is given, and there is no detectable histological 

 damage at this stage. It is in this sense an example of a pure "biochemical 

 lesion." 



The clinical symptoms of thiamine deficiency are connected with the 

 metabolic disturbances. How close the connection between both is, is not 

 precisely known. These symptoms are nearly the same in difTerent animals. 

 Usually there are signs of lameness, of convulsions, accompanied in pigeons 

 with head retraction and in rats with walking in a circle, and of "biochemical 

 lesions." Other signs are anorexia, reduction of growth or decline in weight, 

 and emaciation. As Drummond has emphasized, many of these signs are 

 not independent from each other. Thus the anorexia maj'^ be the cause of 

 the decline in weight. In rats the heart rate is reduced:^ in normal rats the 

 rate is 500 beats per second; in severe deficiency it is not more than 250 

 to 300. This fact was used by Birch and Harris^ as an indication of the 

 severity of thiamine deficiency in rats. (In human beings just the opposite 

 takes place; thiamine deficiency leads to tachycardia For an e.xtensive 

 investigation on the pathology of thiamine deficiency in monkeys, see, e.g., 

 Rinehart et at} 



1 R. L. Swank and M. Prados, Arch. Neurol. Psychiat. 47, 97 (1942); M. Prados and 

 R. L. Swank, Arch. Neurol. Psychiat. 47, 626 (1942). 



2 R. A. Peters, Proc. Roy. Sac. Med. 41, 781 (1948). 



3T. W. Birch and L. J. Harris, Biochem. J. 28, 602 (1934). 



^ J. F. Rinehart, L. D. Greenberg, and M. Friedman, Am. J. Pathol. 23, 879 (1947). 



