162 A. PoLicARD, C. A. Baud, A. Collett, H. Daniel-Moussard, J. C. Martin 



servation agrees with those of Caulfield and Schrag (1964) concerning the presence 

 of apatite in experimental nephrocalcinosis with parathyroid extracts, and thus 

 supports the idea advanced above. 



As regards the presence of apatite in some articular structures in cases of chondro- 

 calcinosis, it should be noted that it was found in particular locations, i. e. in inter- 

 vertebral discs and in a knee meniscus. In the intervertebral discs the apatite deposits 

 were macroscopically dissociated from the areas containing calcium pyrophosphate; 

 the presence of the former seemingly corresponded to foci of connective tissue 

 deterioration. The only sample where apatite and pyrophosphate were associated 

 was taken from a remodelled meniscus in a knee suffering from osteochondrosis 

 dissecans. These findings support the idea that chondrocalcinosis reflects a special 

 local disturbance by itself, independent of, even though sometimes adjacent to, other 

 pathological calcifications which occur in a previous tissue deterioration. 



References 



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Lagier, R.: Les manifestations anatomiques de la chondrocalclnose; comparalson avec celles 

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Si;zE, S. DE, A. HuBAULT, J. Welfling, M. F. Kahn, et J. Solnica: Les arthropathies des 

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Valsik, J., D. ZiTNAN, and S. Sitaj: Chondrocalcinosis artlcularls. Section IL Genetic study. 

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Vix, V. A.: Articular and fibrocartilage calcification In hyperparathyroidism: Associated 

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Infrastructural and Crystallographic Study of 

 Experimental Calcifications 



A. PoLicARD, C. A. Baud, A. Collet, H. Daniel-Moussard, J. C. Martin 



Centre d'Etudes et Rechcrches des Charbonnages de France, VerneuIl-en-Fialatte, Olse, France; 

 Institut de Morphologic, Ecole de Mcdecinc, Geneve, Suisse 



Electron microscopic examinations of experimentally produced calcified deposits 

 led the authors to investigate the nature of the substances deposited both within and 

 outside the cells and to observe the changes induced by different sampling techniques. 



