592 NEW AND UNIDENTIFIED GROWTH FACTORS 



the principal authors. ^^^ The condition is accompanied by extensive calcifica- 

 tion in the joints, body wall and cavity, and upper skeleton; profound 

 changes have been observed in the skull and teeth. Hearing is impaired 

 in the affected animals. Numerous changes have also been recorded for 

 calcium, phosphorus and protein levels in the blood. ''^ 



Beyond this, it is difficult, if not impossible, to make further positive 

 statements regarding the "antistiffness factor," owing in the main to the fact 

 that the assay method was developed and used without adequate controls. 

 Later, a critical examination of the assay by Christensen et al}'^^ and an ex- 

 amination^^^ of the data of Oleson et alP"^ revealed that the assay method 

 could not distinguish between concentrations of active materials that dif- 

 fered by five- or even tenfold. These discoveries necessarily vitiated the claims 

 based on the wrist stiffness assay, whether for isolation of an active principle 

 or for correlation of stiffness with peculiarities in metabolism. The fact that 

 pure compounds have been isolated from cane juice^'^' ^"' ^^^ thus simply 

 reflects the success of chemical separations of materials (chiefly steroid) 

 in the ether-extractable fractions of sugar cane, with no connection between 

 the chemical separations and any physiological index. 



In spite of the unsatisfactory character of many of the studies, it ap- 

 pears possible that a variety of steroids may possess some antistiffness 

 potency. Thus, positive results have been claimed for stigmasterol and 

 various esters of ergostanol and ergostenol (although this is denied bj^ the 

 work of Smith et al}^^). All these tests suffer from the inadequacies of the 

 assay described above. It seems, however, that the assay is capable of de- 

 tecting advanced stages of the condition; addition of these sterols to the 

 "deficient" guinea pig diet over a period of several months might serve 

 quahtatively to establish whether or not the compounds in question can 

 serve as antistiffness agents. Finally, attention should be given to the ques- 

 tion whether this is a nutritional or (perhaps more likely) a pharmacologi- 

 cal principle, i.e., a condition brought about by high levels and imbalances 

 of calcium and phosphorus in the diet. When cotton rats were maintained 

 on diets high in calcium and phosphorus but low in several other minerals, 

 especially magnesium, a similar "calcinosis" was observed, which led to 

 extremely high (23 to 36 %) ash contents in the heart tissue."" The condi- 



"^ W. J. van Wagtendonk and R. Wulzen, Vitamins and Hormones. 8, 70 (1950). 



"5 B. E. Christensen, M. B. Naff, V. H. Cheldelin, and R. Wulzen, /. Biol. Chcin. 175, 



275 (1948). 

 "6 In F. J. Stare, Nutrition Revs. 6, 107 (1948). 



1" D. H. Simonsen and W. J. van Wagtendonk, /. Biol. Chem. 170, 239 (1947). 

 138 H. Rosenkrantz, A. T. Milhorat, M. Farber, and A. E. Milman, Proc. Sac. Exptl. 



Biol. Med. 76, 408 (1951). 

 "9 S. E. Smith, M. A. Williams, A. C. Bauer, and L. A. IMaynard, /. Nutrition 38. 



87 (1949). 

 1^" M. A. Constant and P. 11. Phillips, J. Nutrition 47, 317 (1952). 



