Takeshi Yamanaka

Single camera system for multi-wavelength fruorescent imaging in the heart

Optical mapping has been a powerful method to measure the cardiac electrophysiological phenomenon such as membrane potential(Vm), intracellular calcium(Ca2+), and the other electrophysiological parameters. To measure two parameters simultaneously, the dual mapping system using two cameras is often used. However, the method to measure more than three parameters does not exist. To exploit the full potential of fluorescence imaging, an innovative method to measure multiple, more than three parameters is needed. In this study, we present a new optical mapping system which records multiple parameters using a single camera. Our system consists of one camera, custom-made optical lens units, and a custom-made filter wheel. The optical lens units is designed to focus the fluorescence light at filter position, and form an image on cameras sensor. To obtain optical signals with high quality, efficiency of light collection was carefully discussed in designing the optical system. The developed optical system has object space numerical aperture(NA) 0.1, and image space NA 0.23. The filter wheel was rotated by a motor, which allows filter switching corresponding with needed fluorescence wavelength. The camera exposure and filter switching were synchronized by phase locked loop, which allow this system to record multiple fluorescent signals frame by frame alternately. To validate the performance of this system, we performed experiments to observe Vm and Ca2+ dynamics simultaneously (frame rate: 125fps) with Langendorff perfused rabbit heart. Firstly, we applied basic stimuli to the heart base (cycle length: 500ms), and observed planer wave. The waveforms of Vm and Ca2+ show the same upstroke synchronized with cycle length of pacing. In addition, we recorded Vm and Ca2+ signals during ventricular fibrillation induced by burst pacing. According to these experiments, we showed the efficacy and availability of our method for cardiac electrophysiological research.

A CASE OF SARCOIDOSIS ASSOCIATED WITH OCCLUSION OF AQUEDUCT OF MIDBRAIN AND INAPPROPRIATE SECRETION OF ADH SYNDROME

サルコイドーシスの経過中,中脳水道閉塞によると思われる頭痛,悪心,嘔吐,めまい.難聴,記銘力・指南力低下などの症状を呈し, 副腎皮質ステロイド薬投与および髄液圧減圧術により,一時,小康をえたが,再び,記銘力・指南力低下とともに,低Na,低Cl血症,尿中Na, Cl排泄増加,高張尿などの所見を呈し,腎機能に異常なく,副腎機能不全もないことから, ADH異常分泌症候群と考えられた症例を報告する.本例の脳圧亢進症状,水電解質代謝異常は副腎皮質ステロイド薬が著効を示したことから,いずれもサルコイドーシスによると考えた.