MEDICO-BIOLOGIC RESEARCH 



In a series of works on mineralized dental 

 tissue Engfeldt et al. (49) used micro- 

 radiography in combination with autoradi- 

 ography. This work illustrates the impor- 

 tance of the combined method not only in 

 quantitative analysis but also in the finding 

 of morphological changes (with vitamin D 

 deficienc}^, at teeth germs, in the study of 

 dental tubules, etc.). All this work con- 

 tributes to the better knowledge of calcifica- 

 tion both normal and pathological in teeth 

 and to the understanding of the resistance 

 of teeth to decay. There is no doubt that 

 after overcoming the technical difficulty with 

 the serial sectioning of undecalcified teeth, 

 microradiography will make further progress 

 in dental research. We should also mention 

 important morphological contributions to 

 this research by Roeckert (101) and by 

 Applebaum (2) (3) (4). The first studied 

 the structure of dentine in microradiographs, 

 the second the morphology of so-called 

 "mottled enamel" which, according to his 

 observations" happens to exist quite fre- 

 quently in people using fluoridized water." 



The research has only started in the 

 microradiographical study of such calcareous 

 tissues as tendon and ligament bones, larynx 

 calcifications, etc. One tendon bone and 

 several calcifications of larynx cartilages 

 have been studied by Bohatirchuk. Both 

 kinds of "calcifications" possessed the typ- 

 ical structure of fine-fibered bone: alterna- 

 tion of x-ray opaque and rarefied strata, 

 typical distribution of intraosseous lacunae 

 (colored specimens revealed even the pres- 

 ence of osteocytes within lacunae), calcifica- 

 tion of fibers, typical bone canalization, etc. 

 (Fig. 15). Here microradiography at once 

 answers the question whether the hard tissue 

 is organized bone or a formless calcification. 

 In one case, the hard tissue inside a tumor 

 was found to be true bone. The complete 

 results of these observations will be pub- 

 lished elsewhere. Reasons are not clear, how- 

 ever, why in one case true bone develops and 

 in another a structureless calcium depot 



Fig. 15. Macroradiograph (A) and microradio- 

 graph (B) of ossifying human rib cartilage, 80, 25 n 

 ground section (courtesy of Dr. B^langer), ap- 

 prox. X80. 



MRD presents the bone structure in the calcify- 

 ing cartilage: intraosseous lacunae, stratification. 

 In the right lower part of MRD several cartilage 

 cells are seen with the partialh' calcified c}'topla.sm 

 and cell membrane. 



remains. We believe that microradiography 

 will help to explain these problems. 



Among other calcareous tissues urinary 

 calculi were under study by microradiog- 

 raphy. William H. Boyce et al. (34) found 

 among other interesting data a striking 

 resemblance between the stratified calcium 

 impregnated fibers in fine-fibered bone and 

 the similarly stratified calcium distribution 

 in calculus stroma. This stratification is es- 

 pecially obvious in calcium oxalate stones. 

 They point out that probably an affinity 

 exists between fiber or fibril of connective 

 tissue or collagen fiber and by hydroxyapatite 

 crystals. 



Sufficient has been said above to show that 

 microradiography must be integral to re- 

 search on calcareous tissues. 



Microi-adiography of Tissues per se 

 Low in Absorbing X-rays in Medico - 

 Biological Research. As mentioned above, 

 this microradiography encounters many diffi- 

 culties, particularly in its application to the 

 study of morphology. We know only a few 

 of these morphological contributions. First 

 the w^orks of Lamarque and Turchini (83) 

 should be mentioned, in which morphological 



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