It was performed that the clinical study on the immediate retransplantation of mandibular pieces after 5000R single irradiation, of which visible lesions were removed from resected mandible. The objective cases consist of cancer group (4 cancers) and non-cancer group (a mixed epidermoid and follicular cyst, mycosis, osteoma, and ameloblastoma). There were particular differences between cancer group and non-cancer group as a result of clinical and roentgenological research from 6 months to 34 months after operation. The results obtained were as follows : 1. Cancer group ; 5 months postoperative x-ray films showed that pseudoarticulation formed at the conjunctive portions of retransplanted mandible and host. However, the retransplanted ascending ramus in good conditions functioned it's role. At this time, new bone formation surrounding grafts or enlargenent of transplanted bone itself which observed in the cases of fresh autogenous graft could not be seen. This tendency in the cancer group was considered that the influences due to pre- and post operative x-ray irradiation for surrounding soft tissues were more affected than 5000R single irradiation for retransplanted mandibular pieces. 2. Non-cancer group ; The callous production began at the contact portion of remained mandible and retransplanted mandibular pieces during 2 or 3 weeks after operation. Further, the resorption and smoothing of sharp edges of transplanted mandible were observed. The functional reconstruction of retransplanted mandible continued day after day and it served mandibular arch recovery. Moreover, the additional new bone formation was observed at the alveolaredges or the porton of process coronoideus and it connected partly to the retransplanted mandible. However, the enlargement of transplanted bone observed in fresh autogenous bone grafts could not be seen in present grafts and the speed of functional reconstruction was later in comparison with fresh autogenous bone graft. 3. No recurrent tumor from retransplanted mandibular pieces was observed in this period.

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Deacetylation of N-acetylglucosamine 6-phosphate to produce glucosamine 6-phosphate and acetate has been first demonstrated by Matsushita & Takagi by use of the bovine pa rotid gland extract. In the present paper, a procedure was described for the convenient isolation of the enzyme responsible for the deacetylation from the same source and for its purification by several steps of conventional treatment. A method that has been newly developed for the preparation of N-acetylmannosamine kinase from the hog liver was also reported here. The purified enzyme gave a single peak in the elution pattern from DEAE cellulose column and a single spot on paper electrophoresis, suggesting that the enzyme may consist of a single protein. It showed broad pH optima between 8 and 9 in the reaction mixture with conventional buffer systems, demanding no essential cofactor added. Substrate specificity study revealed that it acted not only upon N-acetylglucosamine 6-phosphate but also upon N-acetylmannosamine 6-phosphate at approximately the same velocity and upon N-acetylglucosamine 6-phosphate less efficiently. The Km for the first substance was calculated to be 9.3×10^<-4>M and that for the second 1.42×10^<-3>M respectively. The enzyme activity was considerably inhibited by divalent cations such as Hg^<++>, Cu^<++> and Cd^<++> and in lesser degree by Sn^<++> and Zn^<++>. Parachloromercuribenzoate was also another potent inhibitor of the activity, suggesting that free sulfhydryl groups in the enzyme protein might be involved in its activity. The enzyme was partially activated and stabilized by the presence of reducing agents such as glutathione, cysteine and sodium sulfite, further supporting above concept. The enzyme was distributed, besides the parotid gland, in the submaxillary gland, tracheal cartilage, intestinal canal, lung, pancreas, kidney and liver of the mammals in considerable amount, but sparsely found in tissues of some lower vertebrates examined.

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