The granular convoluted tubule (GCT) of the mouse submandibular gland (SMG) is a segment of the duct system located between the striated and intercalated ducts, synthesizing a large variety of biologically active polypeptides, including a number of kallikreins. The expression of most of these enzymes are up-regulated by androgens, thyroid hormones, and adrenocorticoid hormones (multihormonal regulation), and morphological appearance of GCT cells is affected by these hormones. However, these hormones suppress mK1, a true tissue kallikrein, exhibiting more abundant expression in the female gland than in male gland. The distribution of a true tissue kallikrein mK1, detected by immunocytochemical technique suggests that the lower content of mK1 in the SMG of the male than female glands are not due to lower synthesis of this enzyme in each GCT cell, but to fewer number of GCT cells expressing this enzyme.

View full abstract

This study examined the effects of mastication for elderly persons, during same material and deferent hardness feeding (boiled well milled rice), before, during mastication and the 30 min post experiment recovery period on the cerebral blood flow and velocity, the energy expenditure, heart rate, respiratory exchange rate and diet induced thermo genesis.
These results demonstrate that masticating enough for hard-boiled well-milled rice increases all parameters, taking hard-boiled well-milled rice to mastication effectives the necessary exchange from carbohydrate to energy expenditure affected resolution of amylase and raised heart rate.
Results suggest that finding activated broad domain of cerebral, because energy expenditure is kept at a high level, increased cerebral blood flow and velocity, and diet induced thermo genesis.

View full abstract

previous study indicated that taking normal boiled rice to mastication is effective concerning diet induced thermo genesis and respiratory quotient. The purpose of this study was to pursue response to cerebral blood flow and velocity during mastication of different hardness boiled rice.
These data suggest that different hardness boiled rice [1: 3] increased cerebral blood flow and velocity, body heat production obtained temperature of tympanum increased cerebral blood flow and velocity due to upkeep of high level body heat production.

View full abstract

In order to clarify the effect of food hardness on masticatory movement, 20 healthy subjects were asked to chew 4 types of gumi-jelly on habitual chewing side. For the ten cycles beginning with the fifth cycle, the gape, masticatory width, cycle time and cumulative value of masseter muscular activity were compared among the four types of gumi-jelly.
1) The gape and masticatory width were smallest for the gumi-jelly containing 5% gelatin, and increased in order as the content of gelatin increased to 6.5%, 8%, and 9.5%. A significant difference was found between 5% and 6.5%, 9.5%, and between 6.5% and 8%, 9.5% for the gape, between 5% and 9.5%, 6.5% and 9.5%, 8% and 9.5% for the width.
2) The cycle time was smallest for the gumi-jelly containing 5% gelatin, and the value increased in order as the gelatin increased. A significant difference was found between 5% and 8%, 9.5%.
3) The masseter muscular activity was smallest for the 5%, and increased in order as the gelatin increased. A significant difference was found between all two types gumi-jelly except for the 6.5% and 8%.
4) From the above results it was concluded that the difference in the hardness of food causes changes in masticatory path, masticatory rhythm and masseter muscular activities and therefore has great effects on masticatory movement.

View full abstract

Juicy fresh gum had been used for measuring the masticatory ability, but manufacturing it stopped, and consequently the selection of substitutive gum became objective. Five kinds of gums were tested as the gum for measuring the masticatory ability and xylitol gum for dentist was the most appropriate. In the case of chewing frequency of 20-60, amount of elution sugar increased proportionally to chewing frequency with the correlation coefficient of R²=0.9946. Also, chewing time increased proportionally to chewing frequency with the correlation coefficient of R²=0.998. Appropriate chewing frequency in measuring masticatory ability using xylitol gum for dentist was 40, which lies middle within the range of 20-60 frequency with proportional relationship between chewing frequency and elution sugar amount. Therefore it is possible to measure the masticatory ability by the use of this gum. Such a result could not be obtained using other gums.
In fact, when the masticatory ability was measured for first grade student in senior high school using xylitol gum for dentist, almost the same form with normal distribution was found for the relationship between amount of elution sugar and number of persons. Moreover, there was the significance at elution sugar amount between boys and girls pupils. In other words, group with strong masticatory ability had 21 persons (16.7%). Group with normal masticatory ability had 85 persons (67.5%) and one with weak masticatory ability had 20 persons (15.9%). These are same results as those in the cases of using juicy fresh gum and accordingly, xylitol gum for dentist can be used for measuring the masticatory ability instead of juicy fresh gum the production of which was abandoned.

View full abstract

There are many reports indicating the importance of relationship between mastication and health. In this study, we first planned to obtain the fundamental data concerning the effect of a novel masticatory foodstuffs on oral and immunological functions. Fifteen healthy subjects (8 males and 7 females) with no signs of periodontitis or no occlusal dysfunction were selected. After taking a novel foodstuffs for two weeks, saliva secretion volume, buffer ability of saliva, bite force, occlusal pressure, NK cell activity and serum zinc concentration were evaluated. The results showed that saliva secretion volume and bite force increased significantly due to taking a novel foodstuffs. Serum zinc concentration was shown a tendency to increase suggesting the possibility of transfer of functional stuffs into the human body. The present study indicates a novel masticatory foodstuffs would be useful as a masticatory agent as well.

View full abstract