Gifu University of Medical Science

About: Gifu University of Medical Science is a education organization based out in Gifu City, Japan. It is known for research contribution in the topics: Imaging phantom & Motion sickness. The organization has 89 authors who have published 202 publications receiving 1350 citations.

The association between impaired perception of verticality and cerebral white matter lesions in the elderly patients with orthostatic hypotension

Abstract: BACKGROUND: The morbidity of orthostatic hypotension (OH) increases with aging and the elderly often complain of dizziness associated with OH, which is implicated in white matter lesions (WMLs) on MRI However little is known how WMLs are contributed to the development of dizziness in elderly patients OBJECTIVE: We evaluated the involvement of cerebral WMLs in the vertical perception in the elderly with OH METHODS: This study consisted of 71 dizzy patients who underwent the examinations including the Schellong orthostatic test and subjective visual vertical (SVV) test RESULTS: The male patients aged 65 years with OH (19 ± 09 ◦ ) showed a significantly higher magnitude of variance of SVV, which reflects an impaired vertical perception, in comparison with the male patients aged 65 years without OH and the male patients aged < 65 years with OH (10 ± 04 ◦ ,0 9± 04 ◦ , p< 005) The variance of SVV significantly correlated with the volume of WMLs in both sides on MRI in the male, but not female patients ( p< 001) CONCLUSIONS: Our results suggest that severe WMLs in the elderly with OH are involved in impaired perception of verticality, resulting in inducing subjective dizziness

Increase in S-adenosylhomocysteine content and its effect on the S-adenosylhomocysteine hydrolase activity under transient high plasma homocysteine levels in rats.

Abstract: The objective of this study was to examine how transient high plasma homocysteine (Hcy) levels affect the metabolism of Hcy, the activity and expression of S-adenosylhomocysteine (SAH) hydrolase which catalyzes both SAH hydrolysis and SAH synthesis. Wistar ST rats (males) were cannulated in the right jugular vein for intravenous infusion of physiological saline or DL-Hcy solutions (15 and 30 mg/mL) for 1 h at 1.1 mL/h/rat. The content of S-adenosylmethionine (SAM), SAH-synthetic activity of SAH hydrolase and the expression of SAH hydrolase mRNA in liver extracts showed no significant difference in the Hcy infused groups as compared to the Control group. On the other hand, the contents of hepatic SAH in the Hcy infused groups were dose-dependent and significantly higher than that of the Control group. Thus, this study showed that hepatic SAH increased without any increase in the SAH-synthetic activity and the expression of SAH hydrolase mRNA under transient high plasma Hcy levels after intravenous infusion of Hcy.

A method for evaluating motion sickness induced by watching stereoscopic images on a head-mounted display

Abstract: It has been reported that even users of virtual environments and entertainment systems experience motion sickness. This visually induced motion sickness (VIMS) is known to be caused by sensory conflict, for instance, the disagreement between vergence and visual accommodation while viewing stereoscopic images. The simulator sickness questionnaire is a well-known tool that is used herein for verifying the occurrence of VIMS. We used the SSQ and also quantitatively measured head acceleration and sway of the center of gravity of the human body before and during the exposure to stereoscopic images on a head-mounted display. During the measurement, the subjects were instructed to maintain the Romberg posture for the first 60 s and a wide stance (with the midlines of heels 20 cm apart) for the next 60 s. We proposed a method to obtain stochastic differential equations (SDEs) as a mathematical model of the body sway on the basis of the stabilogram. While there are several minimal points of time-averaged potential function in the SDEs, the exposure decreases the gradient of the potential function. We have succeeded in estimating the decrease in the gradient of the potential function by using an index called sparse density.