GOT was extracted from the liver of SAM-P/8//Odu (P substrain), which show accelerated senescence, and control SAM-R/1//Odu (R substrain), which show normal aging, at 7, 17, 27 and 37 weeks of age, and age-related changes were investigated in the isozymes separated by electrophoresis on a cellulose acetate membrane.
The ratio of GOT to GPT in the liver decreased in both substrains at 27 weeks to where GOT was equal to GPT. At 37 weeks there was a reversal, with GOT being less than GPT. This decrease in the ratio was significant in the P substrain. In addition, the ratio in the serum was increased at 37 weeks in the P substrain. Although the subcellular distribution of liver GOT increased with aging in the mitochondrial and soluble fractions in both substrains while it decreased in the lysosomal fraction, there was little change in the distribution of liver GPT. There was a large change with aging of the P substrain in the distribution ratio of the GOT-I and GOT-II isozymes in the mitochondrial and soluble fractions from the liver. Serum GOT was composed only of GOT-II in both substrains and it showed no changes with aging.
The above findings relating to GOT showed that there was degeneration of hepatic cells and an increase in the biomembrane permeability in the P substrain at 37 weeks. It is suggested that these are age-related changes associated with accelerated senescence.

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Tooth brushing effectiveness is often very low in the elderly. In order to investigate the reasons for this and examine methods of elevating brushing effectiveness, we compared young adults and the elderly with respect to various characteristics of brushing movements that affect this effectiveness in the rolling and scrubbing methods.
Especially with the rolling method, the brushing force in the elderly was not large enough to effectively cleanse the teeth. From the rotation of the brush and the muscle activity of the hand and arm during brushing, we were able to observe that the brushing was not being done properly as specified by the different brushing methods.
With the rolling method, although the brushing force was high in young adults who had high sensation thresholds of the periodontal membrane and gingiva, this force was low in the elderly, even when their thresholds were high. That is to say, the decrease in brushing force when the rolling method was used by the elderly was independent of the sensation thresholds, and therefore resulted from a deterioration in muscle force, especially in the grip. No causal relation was observed with the scrubbing method in either the elderly or young adults between brushing force and sensation thresholds of the periodontal membrane or gingiva.
The aforementioned decrease in brushing efficiency in the elderly resulting from a deterioration in muscle force could be corrected by applying a method which had been successfully used with young adults whereby they observed their brushing movements and forces recorded on an oscilloscope and, while modifying their technique, carried out repetitious practice to achieve proper brushing.

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In order to better understand the pronunciation of the Chinese language, we investigated the movements of the oral cavity during pronunciation of the pinyinzimu sounds which were defined in 1958.
We found from examination of palatogram and linguogram, and from the contact time of the tongue and palate that, more so than is the case with English or Japanese, it is necessary to make the tip of the tongue contact the palate lightly and for a longer duration in order to correctly pronounce the pinyinzimu sounds. Examination of the velocity in the mandibular incisor region revealed that it is greater during the open phase than the closed phase both for vowels and consonants. It was also found that the velocity during the closed phase is greater for vowels than for consonants.
In addition, examination of the muscles associated with the oral cavity and the degree of opening indicated it was possible to determine the rest position by pronouncing the z, c, and s sounds which are made in the anterior of the mouth with the tip of the tongue (dental sounds).

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We established a human gingival cancer (well differentiated squamous cell carcinoma) xenograft line, GK-1, in nude mice. The tumor line has remained for one year nine months and is in the 17th passage. The take rate was 100% for primary and 97% for serial passaging. The labeling index for BrdU of tumor cells was 37.1% in nude mice. The modal chromosome number of this tumor line was 58 including two large marker chromosomes.

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