Yoichi Yokota

Motion sickness susceptibility associated with visually induced postural instability and cardiac autonomic responses in healthy subjects.

Conclusions This study supports the hypothesis that postural sway and autonomic responses to moving visual stimuli may be associated with motion sickness susceptibility. Characteristics of the cardiac sympathovagal balance during exposure to provocative stimulation may be a marker of individual susceptibility to motion sickness. Objective To assess the relationship between postural and autonomic responses to a simulated visual motion environment and reported susceptibility to motion sickness. Material and methods Fifteen healthy subjects were exposed to sinusoidally oscillating visual motion in roll at frequencies of 0.1–0.4 Hz. Recordings were made of postural sway and respiratory frequency and electrocardiograms were obtained from which heart rate variability (HRV) was computed in order to probe cardiac sympathetic and parasympathetic activity. Results In subjects with a low susceptibility to motion sickness as rated using a standardized questionnaire, there was no significant effect of visual stimulus on postural sway or HRV at any frequency of motion. Subjects with a high susceptibility to motion sickness showed significant postural instability induced by visual stimuli (p<0.01). Visual stimuli presented at a frequency of 0.1 Hz significantly increased the low-frequency power (LF) of HRV, decreased the high-frequency power (HF) of HRV and increased the LF:HF ratio in these subjects (p<0.05).

Disorder of the saliva melatonin circadian rhythm in patients with Meniere's disease

Objectives –  Stress is involved in the development of symptoms of Menieres disease (MD). Stress‐related disease has been reported to be associated with disorders in the circadian rhythm of melatonin (MEL) which regulates that rhythm. We therefore investigated MEL circadian rhythm of patients with MD.

Salivary duct carcinoma: a case report with cytological and pathological features

A 55-year-old Japanese man presented with rapidly growing tumor in the left parotid region without any symptoms. Based on the fine-needle aspiration cytology report of parotid epithelial malignant tumor (suggestive of salivary duct carcinoma), the left parotidectomy was performed. Histopathology and immunohistochemistry examinations revealed features of salivary duct carcinoma. Although salivary duct carcinoma comprising a small proportion of salivary gland tumors and is known to be aggressive, he is free from recurrence and metastases 36 months after the surgery and radiation therapy.