Ryuichi Mochizuki

Functional Imaging of the Human Olfactory Cortex by Magnetic Resonance Imaging

Our understanding of the neural mechanism of human olfaction is still equivocal. Several recent reports document that functional magnetic resonance imaging (MRI) has a potential to visualize dynamic brain function in humans without invasion. In the present study, we applied functional MRI with odor stimulation for the purpose of clarifying the localization of olfactory cortices in the human. We obtained a significant increase in cerebral blood flow in the piriform cortex, orbitofrontal cortex, and inferior medial frontal lobe, corresponding to olfactory cortices. These results suggest that, in the near future, precise diagnosis of the patients with olfactory disorders will be possible using functional MRI with odor stimulation.

Differences in taste responses to Polycose and common sugars in the rat as revealed by behavioral and electrophysiological studies

Behavioral and electrophysiological experiments were performed to examine the suggestion that rats have two types of carbohydrate taste receptors, one for polysaccharides (e.g., Polycose) and one for common sugars (e.g., sucrose). Qualitative difference between the tastes of Polycose and sugars including sucrose, maltose, glucose, and fructose was surveyed by means of a conditioned taste aversion paradigm in which the number of licks for 20 s to each taste stimulus was measured. Aversive conditioning to Polycose did not generalize to sugars, while aversive conditioning to sucrose generalized to other sugars, but not to Polycose. In the electrophysiological study, taste responses of the whole chorda tympani were recorded. A proteolytic enzyme, pronase E, suppressed nerve responses to both Polycose and sugars to less than 50%. A novel anti-sweet peptide, gurmarin, strongly suppressed responses to sugars, but had essentially no effect on Polycose responses. On the other hand, KHCO3 enhanced responses to sugars to about 300%, but had little effect on Polycose responses. These results have confirmed the notion that rats can differentiate the tastes between Polycose and common sugars and that rats have two types of carbohydrate receptors.

Surgical treatment for adductor spasmodic dysphonia – efficacy of bilateral thyroarytenoid myectomy under microlaryngoscopy

Conclusions: Bilateral thyroarytenoid myectomy under microlaryngoscopy by the Muta method (TA myectomy) is a useful surgical treatment for adductor spasmodic dysphonia (ADSD), as a long-term-effect can be expected. Objective: Botulinum toxin (BT) injection is universally accepted as the first choice of treatment for ADSD. However, unfortunately it is not covered by National Health Insurance in Japan and therefore is not a common practice. So, various other therapeutic modalities have been reported. In the current study, we conducted bilateral TA myectomy on patients with ADSD and evaluated the results. Patients and methods: Seven patients with ADSD who visited our department between 1999 and 2005 are described. The details of BT injection and the surgical procedure were described to the patients. As all seven patients wanted to undergo this surgical therapy, they all underwent bilateral TA myectomy. Results: The constriction was eliminated immediately after surgery and the patients became capable of smooth phonation. Hoarseness was recognized, but it began to ease after 1–2 months and was corrected to B grade 1–0 of the GRBAS scale approximately 6 months after the surgery. Improvement in the condition was noted in all seven patients according to evaluations based on the mora method. All patients are currently in the B grade 0.

Effects of cooling the pharyngeal mucosa after bipolar scissors tonsillectomy on postoperative pain

Abstract Conclusion: Bipolar scissors tonsillectomy followed by cooling down the pharyngeal mucosa has advantages in terms of postoperative pain and intraoperative blood loss compared with cold dissection. Objectives: The purpose of this study was to compare the postoperative pain between bipolar scissors tonsillectomy followed by cooling the pharyngeal mucosa and a traditional cold dissection. Methods: A total of 189 patients aged more than 16 years were operated due to habitual tonsillitis, obstructive sleep apnea syndrome, and IgA nephropathy. Of these, 79 patients were operated using bipolar scissors followed by cooling the pharyngeal mucosa with 4°C saline for 10 min just after the removal of tonsils. The other 110 patients underwent cold dissection tonsillectomy. Outcome measures were intraoperative blood loss, operative time, postoperative pain evaluated on a visual analog scale, and postoperative secondary hemorrhage. Results: Significantly lower levels of intraoperative blood loss and less postoperative pain were obtained in bipolar scissors tonsillectomy followed by cooling the pharyngeal mucosa compared with cold dissection. Postoperative hemorrhage needing hemostatic surgery occurred in 2 of 79 patients who underwent bipolar scissors tonsillectomy with cooling, while it occurred in 1 of 110 patients after cold dissection. However, the difference was not statistically significant.

Computed tomographic assessment of the causal factors of unsuccessful medialization thyroplasty

Abstract Conclusion: The present results demonstrate that a small implant size, undercorrection of the vocal fold, antero-posterior implant malposition, and the use of expanded polytetrafluoroethylene (ePTFE) are the primary factors that cause a poor outcome of medialization thyroplasty (MT). Objectives: To assess the postoperative laryngeal condition using computed tomography (CT) in patients with unilateral vocal fold paralysis who underwent MT alone, and to identify the primary causal factors in terms of the surgical procedures that affect the outcomes of MT. Methods: Twenty-two patients who underwent MT alone were divided into two groups based on either the maximal phonation time or the perceived vocal breathiness. Two laryngologists assessed the postoperative laryngeal CT images during sustained vowel phonation and judged whether there were abnormalities of the arytenoid cartilage position, window position, implant size, and implant position, as well as the degree of correction of the vocal fold. As implant material, a silicone block, ePTFE, and hydroxyapatite had been inserted in 2, 9, and 11 patients, respectively. Comparisons of the prevalence of abnormalities in the abovementioned factors between the different outcomes and between the types of material used for the implant were performed. Results: Twelve patients with a poor outcome and 10 with a good outcome showed 36 and 18 abnormal findings identified by either of the two laryngologists, respectively. In the poor outcome group, a smaller implant size and undercorrection of the vocal fold showed both high kappa values and a significantly higher prevalence than those in the good outcome group (p < 0.001 and p < 0.05), respectively. The comparison between material types demonstrated that the sheet-like material (ePTFE) group exhibited a significantly higher prevalence of undercorrection than the block-like material group (p < 0.05).

Power-Assisted Partial Adenoidectomy (PAPA) with Total Tonsillectomy for Pediatric Obstructive Sleep Apnea Syndrome

Obstructive sleep apnea syndrome (OSAS) in youth causes various sequelae—life-threatening, body composition and school performance. Adenotonsillar surgery is beneficial for treating pediatric OSAS, however, the traditional methods pose some problems such as re-multiplication of adenoids. We performed total tonsillectomy and Power-Assisted Partial Adenoidectomy (PAPA) in 111 children for 3 years and 25 cases were examined Oxygen Desaturation Index 3% (ODI 3%) during sleep with a pulseoxymeter before and after the operation.Their ODI 3% improved significantly after surgery. No long-term complications, such as relapse of OSAS and immunodeficiency, have occurred. PAPA with total tonsillectomy is very useful for the treatment of pediatric OSAS.