526 THE TOCOPHEROLS 



of vitamin E was not clearly established until a later date.^^' ^^ Experimental 

 work with this group of animals has centered largely aromid the rabbit, 

 because of the ease with which symptoms can be produced and made to 

 disappear by vitamin E therapy and the sequence repeated as often as 

 desired. ^^ In respect to this striking responsiveness to tocopherol therapy, 

 which involves rapid biochemical and morphologic repair, the dystrophic 

 process in the rabbit differs from that in the rat. On the whole, the muscle 

 lesions described in rabbits and guinea pigs more closely resemble the acute 

 or explosive type exemplified by late-lactation paralysis than the more 

 chronic type described below. However, it seems probable that the basic 

 alterations occurring within the muscle fibers are fundamentally similar in 

 all instances. Recent studies^^** indicate that the initial disturbance, which 

 precedes loss of cross striations or other microscopic change, involves loss 

 of actomyosin or alterations of the submicroscopic pattern in which acto- 

 myosin is organized. 



(3) Adult, or Chronic, Dystrophy. In young rats which spontaneously 

 recover from late-lactation paralysis there is, within a week or so, a dra- 

 matic diminution in the intensity and extent of the muscle lesions. At one 

 month of life only occasional fibers are dystrophic; the remaining muscu- 

 lature is normal and shows little or no connective tissue replacement of 

 degenerated fibers. With continued deficiency there is progressive involve- 

 ment of more and more fibers, usually in groups such that a patchy distri- 

 bution of lesions results, which may be extensive enough to cause locomotor 

 disabilities by the fifth or sixth month of life. In rats whose vitamin E re- 

 serves prevent the occurrence of early lesions, those of the later type may 

 not be evident microscopically until the fourth or fifth month, and gross 

 evidence of dystrophy not apparent until the eight to tenth month of life. 



Gross and microscopic details of adult dystrophy in rats lia\'e been given 

 by Ringsted,^^ Einarson and Ringsted,"^ Evans et al.,'- Knowlton et al.^^ 



67 C. G. Mackenzie and E. V. McCollum, Science 89, 370 (1939) : ./. Nutrition 19, 



345 (1940). 

 «8 C. G. Mackenzie, J. B. Mackenzie, and E. V. McCollum, Science 94, 216 (1941); 



./. Nutrition 21, 225 (1941). 

 s^-C. G. Mackenzie, Proc. Soc. Exptt. Biol. Med. 49, 313 (1942). 

 ^^'•'M. Aloisi, A. Ascenzi, and E. Bonetti, ./. Pathol. Bactcriol. 64, 321 (1952). 



70 A. Ringsted, Biocliem. J. 29, 788 (1935). 



71 L. Einarson and A. Ringsted, Effect of Chronic Vitamin E Deficiency on the Nerv- 

 ous System and the Skeletal Musculature in Adult Rats. Levin and Munksgaard, 

 Copenhagen, 1938. 



72 H. M. Evans, G. A. Emerson, and I. R. Telford, Proc. Soc. E.rptl. Biol. .Maf 38, 

 625 (1938). 



73 G. C. Knowlton, H. M. Hines, and K. M. I^rinkhous, Proc. Soc. E.rptl. Biol. Med. 

 41, 453 (1939); 42, 804 (1939). 



