ABSTRACT-The usefulness of bis-(1,3-dibutylbarbituric acid)-trimethine oxonol (DiBAC4(3)), a voltagesensitive fluorescent dye, for the measurement of membrane potentials (MPs) was evaluated in HEK293 cells, where a or a plus b 1 subunits of large conductance Ca 2+-activated K + (BK) channels were expressed (HEKBKa and HEKBKab). The fluorescent intensity of DiBAC4(3) was measured at various potentials under voltage-clamp for calibration to estimate the absolute MP semi-quantitatively. The resting MPs measured with DiBAC4(3) were roughly comparable to those recorded with a microelectrode; the MP in HEKBKab was 10 -20 mV more negative than that in native HEK. In HEKBKa, the membrane hyperpolarization induced by 10 m M Evans blue, a BK channel opener, was detected with DiBAC4(3). NS-1619, another BK channel opener, induced gradual but substantial change in F/FK even in native HEK, while the BK channel opening effect was detected. Oscillatory membrane hyperpolarization was induced in HEKBKab by application of 10 m M acetylcholine via increase in intracellular Ca 2+ concentration. The oscillatory hyperpolarization was, however, detected only as a slow hyperpolarization with DiBAC4(3). It can be concluded that relatively slow effects of BK channel modulators can be semi-quantitatively measured by use of DiBAC4(3) in HEKBK, while the limited temporal resolution and possible artifacts should be taken into account.

X-ray and cineradiography measurements were used to compare the suspension effect and stability of a TSB trans-tibial prosthesis with an Icelandic Roll-On Silicone Socket (ICEROSS) system to that of a PTB trans-tibial prosthesis. The suspension effect was measured by the distance between the tibia and the socket in both suspension position and weight-bearing position in both type of prostheses. The suspension effect of the TSB prosthesis (2.53 ± 0.90cm) was superior to that of the PTB prosthesis (3.60 ± 0.56cm) (p<0.05) by x-ray measurement. The suspension effect of the TSB prosthesis (0.1, 0.4, 0.72cm) was superior to that of the PTB prosthesis (0.3, 0.48, 1.03cm) (p<0.01, p<0.05) by cineradiographic measurement. The stability was measured as the angle between the axis of the tibia and the prosthesis at the time of heel contact and toe off. The angle change of the TSB prosthesis was statistically smaller than that of the PTB prosthesis.

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We have designed a new polycentric knee adopting a hydraulic unit and an intelligent mechanism. The biomechanical parameters of this prototype, such as the stance duration, peak knee flexion angle in stance and swing, peak hip flexion angle, and peak hip extension moments were analyzed at three different cadences (88, 96, 104 steps/min) in three amputees, and then compared to those of polycentric hydraulic knees currently in use. The same parameters were also measured for 10 healthy volunteers and subsequently analyzed. In the prototype, almost all the values of the parameters showed no significant variety in individuals at the different cadences. The situation was the same with the healthy volunteers. However, the values of the parameter for the conventional knee varied significantly with the individual at the different cadences. The prototype may be of practical use, contributing to a stable walk even at different cadences.

No abstract