52 C. B. Sledge 



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Thornton, P. A.: Unpublished. 



— , and D. Brownrigg: Calcium utilization and skeletal development in chicks as influenced 

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— , C. W. Weber, and R. E. Moreng: The effect of ascorbic acid in the diet of adult chickens 

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Lysosomes and Cartilage Resorption in Organ Culture 



C. B. Sledge 



Strangeways Research Laboratory, Cambridge, England 



and 



Department of Orthopedics, Harvard Medical School, Massachusetts General Hospital, 



Boston, Mass., U.S.A. 



The work of Bassett and Herrmann (1961) and Bassett (1964) has shown that 

 variations in environmental oxygen exert a modulating influence on skeletal tissues in 

 culture. GoLDHABER (1963) has found that exposure of neo-natal mouse calvaria in 



organ culture to elevated par- 

 tial pressures of oxygen results 

 in bone resorption and in- 

 creased osteoclasis. The mecha- 

 nism of these interesting effects 

 is unexplained. 



In this work, the cartilagi- 

 nous limb-bone rudiments of 

 8-day chick embryos have been 

 ^- ^ ^^ exposed to elevated partial pres- 



sures of oxygen on a comple- 

 tely synthetic medium. This re- 

 sults in extensive loss of meta- 

 chromatic material throughout 



Fig. 1. Top: control rudiment exposed to 20«/o oxygen for 6 days. the shaft of the rudiments 



Toiuidine blue. XIO. — Bottom: contralateral rudiment exposed (Fig 1) This loSS of mCtachrO- 



to 85% oxygen for 6 davs. Toiuidine blue. XIO ^ °' /' 



masis IS accompanied by normal 

 synthesis, but increased release of hexosamine into the medium. Thus, both the 

 histological appearance and solubilization of mucopolysaccharide resemble the effect 

 of excess of vitamin A. Since this vitamin has been shown to produce matrix degra- 





