Minoru Yamaoka

Serum dipeptidyl peptidase activities as a possible marker of oral cancer

Serum glycyl‐1‐prolyl 4‐methyl‐coumaryl‐7‐amide (gly‐pro‐MCA) hydrolase (DPP IV) and L‐lysyl‐L‐alanyl β‐naphthylamide (lys‐ala‐β NA) hydrolase (assumed to be DPP II) activities were measured in patients with oral squamous cell carcinoma and healthy subjects. The mean serum DPP IV activity of all cancer patients was significantly (P < 0.001) decreased, compared with that of healthy subjects. Although there was no significant difference between the stages by International Union Against Cancer (UICC) classification (1978), DPP IV levels tended to change dynamically, reflecting the clinical status during therapies. The serum DPP IV activity of patients with a fair prognosis was significantly elevated toward the normal range, whereas the activity of patients with a poor prognosis was significantly decreased (P < 0.05). In contrast, the mean serum lys‐ala‐β NA hydrolytic activity of cancer patients was significantly (P < 0.001) increased, compared with that of healthy subjects, and was changed reciprocally to DPP IV activity. The correlation of these two serum enzyme activities with tumor weights also was observed in animal models using nude mice transplanted with human KB carcinoma cells and hamsters transplanted with BHK21 cells. These results indicate that these serum enzyme levels may become an aid for the diagnosis of malignant tumors and for estimating the prognosis of the patients.

Serum dipeptidyl peptidase (DPP) IV activities in oral cancer patients.

Dipeptidyl peptidase (DPP) IV activities in normal human sera and in the sera of patients with malignant tumors of the oral region were assayed. Patients with oral squamous cell carcinoma had significantly lower enzyme activity than that of normal controls (p less than 0.001). Patients with advanced carcinoma showed a more significant reduction of serum enzyme activity. On the other hand, in oral squamous cell carcinoma patients with hepatic dysfunction, the serum enzyme activity was significantly increased (p less than 0.02).

Visual training for velopharyngeal closure in cleft palate patients; a fihrescopic procedure (preliminary report)

Velopharyngeal closure in various tasks was examined in 59 cleft palate patients with persistent velopharyngeal incompetence using nasopharyngeal fibrescopic (NPF) examination. The degree of velopharyngeal closure was analyzed according to the categories reported previously by Yamaoka (1973) and Matsuya et al. (1979). The NPF self-training system was developed and applied to those patients so as to investigate a longitudinal effect of the NPF in velopharyngeal closure mechanism. The training was performed every two weeks for nearly one year. The results indicated that the patient who showed complete velopharyngeal closure during blowing and/or several productions of speech samples could attain a much better improvement in all speech samples after one year of self-training. On the other hand, the patients who did not show complete velopharyngeal closure during all tasks, failed to improve the velopharyngeal closing mechanism. The ability to close the velopharynx during swallowing was seen in all patients examined. However, it appeared to have nothing to do with the prognosis of velopharyngeal closure. The data suggested that the NPF self-training system provided a strong neuro-muscular signal for velopharyngeal movement. Besides, it was considered that the NPF was a useful tool for activation of velopharyngeal activity by way of visual feed-back control.

The submucosal Island flap in the closure of oro-antral fistula

A submucosal island palatal flap technique was used successfully in seven patients for closure of large oro-antral fistulae. The technique provides not only an island flap of submucosal connective tissue to close the fistula, but a flap of mucosa to cover the raw area of palatal bone. The advantages of the technique are that healing is satisfactory without denuded bone, the island flap has excellent mobility and does not produce bunching of the mucosa of the hard palate and recipient site, and dentures may be fitted early following the excellent healing of the wound.

A fiberscopic study of velopharyngeal closure in patients with operated cleft palates.

We studied the differences in how velopharyngeal closure is learned and obtained by operated cleft palate patients during various activities. Sixty-eight operated cleft palate patients, who had complete closure during swallowing, were examined with the nasopharyngeal fiberscope to determine the extent of velopharyngeal closure while they were producing pressure consonants or vowels, and during blowing. We concluded that complete closure when producing vowels was the most difficult to obtain, and closure when producing pressure consonants was a little more difficult than that during blowing.