MEDICO-BIOLOGIC RESEARCH 



ical cases. Bohatirchiik (1955) (28) immersed 

 sections 35-70 n thick, both primary and 

 metastatic from experimental and human 

 tumors, into thorotrast for some time and 

 radiographed them afterward. The selective 

 adsorption of thorotrast by tumor tissue in 

 case of hver metastasis (Fig. 19) is quite 

 obvious (Brown-Pearce rabbit cancer). This 

 increase of adsorption is conspicuous in spite 

 of the fact that the normal liver tissue (RES 

 elements) adsorbs OM selectively (see upper 

 part of Fig. 19). It was also found that in 

 some cases of liver metastases the adsorption 

 of thorotrast was increased by liver tissue 

 in which no cancer cells were present (Fig. 

 20). It is probable that this phenomenon is 

 due to pre-cancerous changes in the liver 

 parenchyma. This observation deserves at- 

 tention because patho-histology has not 



Fig. 20. Alicrophotograph of :\IRD Xo. 19 at 

 the higher magnification (approx. X200). Although 

 the demarcation line between the tumor and nor- 

 mal liver tissue is conspicuous, many areas in 

 "normal" tissue are seen (e.g. in the upper right 

 corner) which absorb thorotrast selectively. It is 

 believed that these areas represent the precancer- 

 ous stage of the tissue. 



Fig. 19. AIRD of rabbit liver with metastases 

 of Brown-Pearce tumor. PM thorotrast coloring, 

 10 /x, approx. X80. Large metastasis is conspicuous 

 in the right lower part of the specimen. Note the 

 selective absorption of thorotrast by tumor cells 

 and sharp demarcation line between the normal 

 and cancerous tissue. 



Fig. 21. AIRD-s of cat's brain in ca.se of injury. 

 (A) in place of injury (frontal lobe), (B) in some 

 neighborhood of middle brain. PM thorotrast 

 coloring, 10 n, approx. XSO. Selective adsorption 

 of thorotrast by some elements of brain tissue is 

 conspicuous not only in the place of injur}' but also 

 at a considerable distance from it. The origin of 

 elements selectively absorbing thorotrast is not 

 clear as yet. It is believed however, that the de- 

 generated myeline is this absorber. 



quite a reliable method for the morphological 

 determination of pre-cancerous changes. 



In another work (unpublished) Auer and 

 Bohatirchuk investigated the pos.sibility of 

 x-ray coloring technique in case of degener- 

 ated nerve fibers. Some signs were found of 

 selective adsorption of thorotrast by these 

 fibers (Figs. 21 A and B). However, results 



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