1967 Volume 58 Issue 1 Pages 46-63
The experimental induction of bladder tumors was attempted in each group of 15 adult female mongrel dogs by the method of oral administration of betanaphthylamine and local application of 20-methylcholanthrene. The group of the local application of 20-methylcholanthrene was divided into 3 subgroups according to the difference of the method, a) a cotton thread prepared with 3% 20-methylcholanthrene in tween 80 oil solution for a day was sutured to the bladder walls of 5 dogs, b) a 100mg paraffin pellet containing 30% 20-methylcholanthrene was located in the submucosal layer of the bladder of the other 5 dogs, c) the same kind of a paraffin pellet weighing 1.0 to 2.5g was put in the bladder of the other 5 dogs.
The results were as follows:
1) In the group of oral administration of beta- naphthylamine, the benign and malignant tumors appeared in 10 bladders after 16 to 21 months.
2) The cystoscopic findings before development of the tumor were hyperemia, telangiectases, small brown spots suggestive of epithelial thickening, hyperplasia, and polyps.
3) The histological examination of the tumors and the interstitial connective tissues was done on each bladder.
4) In the group of local application of 20-methylcholanthrene, abnormal epithelial hyperplasia around the paraffin pellet was seen in only one bladder of the b) subgroup after 14 months.
