HETEROTOPIC BONE FORMATION

PARTICIPATION OF Ca METABOLISM

Abstract

The renal vessels of the rabbits were laterally ligated to produce bone formation in the related kidney and its mechanism was investigated.
1. In most of the cases, it takes 16 days for nephrocalcinosis to develop in the vessel-ligated kidney.
2. The weight and the size are usually larger in the ligated kidney until the 10th day after the ligation. On and after the 20th day, however, the unligated kidney grows larger and heavier while atrophy is observed in the other.
3. The development of a bone tissue with bone marrow is seen in all the cases on the 35th day. Near this bone tissue or in its adjacency is seen the pelvisepithelium. Calcification is strongly indicated chiefly in the cortex.
4. The symptoms of secondary hyperparathyroidism are histologically recognized in the parathyroid of the rabbits that have developed bone tissue in the kidney.
5. The variation of serum Ca and alkaline phosphatase in the animals remained within the normal range.
6. ³²P and ⁴⁵Ca were administered to the animals and the amount of the isotopes contained in the kidneys and blood was measured. The amount of ³²P showed no significant difference between both the kidneys, whereas that of ⁴⁵Ca was three times larger in the ligated kidney than in the normal one on the 16th day after the ligation, sixteen times on the 40th day, and then dropped to nearly the same ratio on the 120th day as before the ligation.
From the foregoing results of the experiment, a fact was disclosed that Ca compounds are mobiliged in a large quantity during bone formation. Therefore it may be concluded that Ca compounds are the essential factor in bone formation. The bone formation seen after a plastic surgery on the urinary tract may be attributed to the ischemia, the deposit of Ca compounds, and the intact presence of the epithelium in that region.