382 RIBOFLAVIN 



sheaths of the sciatic nerves, axis cylinder swelling, and fragmentation. 

 Myelin degeneration and gliosis in the spinal cord have also been observed. 



Histological changes in the skin have been described by Wolbach and 

 Bessey^*' ^^' ^^ as follows: "We find that the initial responses are in the epi- 

 dermis and its appendages. The vascular engorgement, so characteristic 

 of pyridoxine deficiency, does not occur. The epidermis as a whole shows 

 little change other than a moderate hyperkeratosis. In some locations there 

 is slight hyperplasia of the epidermis, particularly of the snout and sides 

 of the head, possibly related to scratching. Sebaceous glands, including the 

 Meibomian glands of the eyelids, become somewhat atrophic. There is an 

 increased rate of shedding of hair which we believe to be the result of separa- 

 tion of the cornified anchoring cells from the epithelial sheaths. The out- 

 standing and thus far, to us, distinctive feature of the deficiency is the 

 effect upon regeneration of hair follicles and hair formation. In the late 

 stage of the deficiency, regeneration of the hair follicles does not occur or 

 is incomplete. Follicles engaged in hair formation during the establishment 

 of the deficiency undergo atrophy and for a time continue to form imper- 

 fect hair. The atrophy is apparent in all parts of the hair follicle but is 

 more evident in the matrix. The cuticular cells continue longest but undergo 

 atypical cornification. Thus various degrees of retardation of hair produc- 

 tion are found in a given area of skin; complete suppression, hair roots 

 represented by loosely packed columns of cornified fusiform cells and hair 

 roots consisting of medulla with imperfectly formed cortical substance. 

 Sharply flexed or buckled hair follicles are common, presumably occasioned 

 by the lack of support normally afforded by the forming hair shaft or root. 

 In cross section, the hair roots are often oval or flat in outline. The micro- 

 scopic appearances account satisfactorily for the gross appearances of the 

 sparsely distributed hair. The gross impression of thickening of the skin 

 may be accounted for by the persistence of many atrophic regenerated 

 follicles because these may and often do extend to the depth of normal ac- 

 tive follicles (i.e., to the muscle panniculus), and owing to their number, 

 should affect the textiu'e of the skin. In 48 hours after riboflavin therapy, 

 there is marked restoration of normal appearances of the follicles and in 

 72 hours the epithelium of the follicle has assumed normal appearances. 

 The matrix cells respond first." 



According to Kornbcrg cl al.^^ rats fed a diet deficient in riboflavin de- 

 veloped granulocytopenia in about 5.0% of the cases and, less frequently, 

 anemia. The granulocytopenia responded to foli(^ acid more frequently than 

 to riboflavin. However, the anemia observed was alleviated in more rats 



^9 S. B. Wolbach, J. Am. Med. Assoc. 108, 7 (1937). 



60 S. B. Woll)ach and O. A. Bessey, Science 91, 559 (1940). 



" A. Kornberg, F. S. Daft, and W. H. Sebrell, Arch. Biochem. 8, 431 (1945). 



