Kinetic and thermodynamic analysis of the cyclodextrin-allyl isothiocyanate inclusion complex in an aqueous solution.

The decomposition of allyl isothiocyanate (AITC) in an aqueous solution was depressed in the presence of cyclodextrin (CD), it's suppression effect increasing in the order of none < beta-CD < alpha-CD. The results of kinetic and thermodynamic analysis of the CD-AITC inclusion complexes showed that the inclusion process was mostly governed by an enthalpy change (delta H degree) rather than by an entrophy change (delta S degree), and that Van der Waals forces played a primary role int he inclusion. Steric factors were important for the reaction activity of AITC inclusion into the CD cavity, especially significant being the stereospecificity between the size of the CD cavity and the AITC molecule which is the main factor concerning it's activity. Our results suggest that the association stability and activity of the included AITC molecule are important factors in the suppression mechanism for CDs. Therefore, both these factors would make an alpha-CD-AITC system more advantageous than a beta-CD-AITC system, and the marked suppression effect of alpha-CD on the decomposition of AITC can be attributed to the formation of inclusion complexes in an aqueous solution.

3D analysis of nystagmus in peripheral vertigo.

Three-dimensional analysis of nystagmus was carried out in patients with peripheral vestibular diseases using a computerized image recognition technique developed by us. In the present study, we analyzed data from patients with Meniere's disease and vestibular neuritis with the central premise of localizing the pathology in the peripheral vestibular organs. In Meniere's disease, the recordings of all subjects showed two components of eye movements, namely the horizontal and torsional components. On the other hand, most of the patients with vestibular neuritis exhibited all three components of spontaneous nystagmus. The horizontal and vertical components of nystagmus in patients with vestibular neuritis were directed towards the contralateral side of the lesion and upwards. Based on these results and with reference to animal experiments that have related the eye movements with each labyrinthine end organ, it can be speculated that in Meniere's disease the pathological changes may involve all semicircular canals, whereas the main site of lesion in vestibular neuritis could be localized to the superior vestibular nerve.