Tadashi Ogura

Occlusal Disharmony Affects Plasma Corticosterone and Hypothalamic Noradrenaline Release in Rats

Few neuro-endocrinological studies have examined the relationship between occlusal disharmony and stress. To determine the effect of occlusal disharmony on the central nervous system, we measured plasma corticosterone and extracellular noradrenaline in the vicinity of the hypothalamic paraventricular nucleus in rats both with and without incisal caps. After the caps were set, plasma corticosterone and extracellular noradrenaline levels gradually increased, reaching a peak at 8.5 and 6.5 hours, respectively, after which they decreased. Furthermore, plasma corticosterone and extracellular noradrenaline levels increased in a circadian fashion around the onset of the dark phase in rats without caps, but not in rats with caps. These results suggest that occlusal disharmony causes chronic stress in the rat.

Effects of three principal constituents in chewing gum on electroencephalographic activity

The effects of three principal constituents (sugar, spearmint, and gumbase) in chewing gum on EEG findings in 20 normal subjects were investigated. After they chewed the gumbase, theta activity decreased significantly at Fp2, O1, T3, T4, F4, P3, and Pz; alpha activity increased significantly at O1 and decreased significantly at Fp1, and beta activity increased significantly at Fp1, Fp2, O1, T3, T4, P3 and Pz. After they inhaled the spearmint, alpha activity decreased significantly at 02, F3, P4, and Fz, and beta increased significantly at 02, F3, P4, and Fz. The mean frequency of the alpha band was significantly higher than after 1 min at rest without inhalation. After the subjects chewed the gumbase with sucrose, theta activity increased at Fp2 and Fz; alpha activity increased significantly at T3; and beta activity decreased significantly at Fpl, Fp2, F4, P3, P4, Fz, and Pz. The mean frequency of the alpha band was significantly lower than after 1 min at rest without it at almost all the positions. These results suggest that the gumbase with sucrose induced relaxed concentration effects while inhalation of spearmint induced arousal effects. The chewing of gumbase showed arousal tendency.

Liquid meal attenuates meal anticipation in rat adrenocortical activity

Effects of dietary consistency were examined on the development and persistence of meal anticipation in adrenocortical activity in rats under restricted daily feeding (RF), in which food supply was restricted to a fixed time of day. Restricted daily solid meal produced the anticipatory hormone peak in 8 days, whereas restricted daily liquid meal produced the peak in 12 days. The developed hormone peak was less prominent by liquid meal than by solid. The anticipatory corticosterone peak developed by solid meal persisted throughout the period examined (3 weeks) after the termination of RF, whereas the peak developed by liquid meal disappeared after the first week. It is concluded that liquid meal attenuates the meal anticipation in the adrenocortical activity in rats under RF.

Analysis of the Questionnaire on the Sport Injury to High-school Baseball Pitchers.

Background: In this study, we attempted to determine the connection between throwing injuries, especially to the shoulder or elbow, and the amount of pitching practice, in high-school pitchers. Methods: We distributed questionnaires to 67 high-school baseball pitchers and had them answer questions on the following: their sports career, past sport-related injuries, the amount of baseball practice per day and per week, the number of throws per day, and the number of non-throwing day per week. Using an unpaired T-test, we looked for statistical relationships between throwing injuries and the above factors. Results: Of the 67 cases that answered our questionnaire, 53 (79.1%) answered that they had suffered sports-related injuries in their careers. Of these, 48 (71.6%) had suffered throwing injuries to the shoulder or elbow. Our examination showed that 34 pitchers (50.7%) currently had derangement of the shoulder or elbow, and the questionnaires showed that these pitchers had spent much more time practicing throwing in elementary school and junior high school than those without these problems. Conclusion: Excessive throwing practice in elementary school and junior high school may lead to derangement of the shoulder or elbow.

A preliminary study on equilibrium function in the subjects with temporomandibular joint dysfunction syndrome, and anterior open bite using a stabilometer.

顎関節症発症の初発期である思春期を対象に, 顎関節症症状と平衡機能の調査を行い, 両者の関係を検討するとともに, 開咬を認める者の平衡機能についての検討も行った結果, 以下のような結論を得た.1. 対照群と比較して疼痛群では, 外周面積が5%の危険率で有意に大きく, 単位面積軌跡長が1%の危険率で有意に小さい値を示したが, いずれも時田の示した健常者の標準偏差内の値だった.2. 対照群と比較して雑音群では, 単位面積軌跡長が1%の危険率で有意に小さい値を示したが, 疼痛群と同様, 時田の示した健常者の標準偏差の範囲内の値だった.3. 対照群と比較して開咬群では, 全ての検査項目で有意差はないものの, 外周面積は大きく, 単位面積軌跡長は小さい傾向が認められた.このように, 顎関節症ならびに開咬は, 平衡機能と何らかの関係をもっている可能性が示唆された.