The chewing-related neuronal mechanism underlying stress relief, was evaluated by use of fMRI. For this purpose we examined the effect of chewing a moderately hard gum without any taste (X type, Lotte Co. LTd., Tokyo) on brain activation caused by a noisy sound stress, on plasma levels of catecholamines and ACTH. The stress significantly increased the blood oxygenation level-dependent (BOLD) signals in the amygdala and the medial prefrontal cortex, and elevated plasma levels of noradrenaline, dopamine and ACTH. However, this chewing suppressed not only the stress-induced increase in BOLD signals in these two regions, but also the stress-induced elevation in plasma levels of these catecholamines and ACTH. The results suggested that chewing might be a useful therapy for reducing stress.
Stress ; Mastication ; Adrenocorticotropic hormone measurement ; Plasma ; Stress bismuth subsalicylate

Background: and Purpose To assess the long-term outcomes of intracranial dural arteriovenous fistula (DAVF) treated with stereotactic radiosurgery (SRS) alone or embolization and SRS (Emb-SRS) and to develop a grading system for predicting DAVF obliteration. Methods: This multi-institutional retrospective study included 200 patients with DAVF treated with SRS or Emb-SRS. We investigated the long-term obliteration rate and obliteration-associated factors. We developed a new grading system to estimate the obliteration rate. Additionally, we compared the outcomes of SRS and Emb-SRS by using propensity score matching. Results: The 3- and 4-year obliteration rates were 66.3% and 78.8%, respectively. The post-SRS hemorrhage rate was 2%. In the matched cohort, the SRS and Emb-SRS groups did not differ in the rates of obliteration (P=0.54) or post-SRS hemorrhage (P=0.50). In multivariable analysis, DAVF location and cortical venous reflux (CVR) were independently associated with obliteration. The new grading system assigned 2, 1, and 0 points to DAVFs in the anterior skull base or middle fossa, DAVFs with CVR or DAVFs in the superior sagittal sinus or tentorium, and DAVFs without these factors, respectively. Using the total points, patients were stratified into the highest (0 points), intermediate (1 point), or lowest (≥2 points) obliteration rate groups that exhibited 4-year obliteration rates of 94.4%, 71.3%, and 60.4%, respectively (P<0.01). Conclusions SRS-based therapy achieved DAVF obliteration in more than three-quarters of the patients at 4 years of age. Our grading system can stratify the obliteration rate and may guide physicians in treatment selection.