Development of a pulsatile flow-generating circulatory-assist device.

We developed a new circulation-assist device that can generate pulsatile assist flow synchronized with the patient's diastolic phase. The device is composed of a drainage tube, a centrifugal pump, an oxygenator, and a sending tube. A portable magnetic valve device composed of a pulse generator and a tamper, which produces intermittent mechanical compression, is attached to the pillow of the sending tube.

Interaction between liposomes and RBC in microvessels in vivo.

Liposomes are phospholipid vesicles that can serve as carriers of biologically active agents in vitro and in vivo. Here, we describe the movement of liposomes suspended with blood flowing in capillaries. Liposomes were coated with a polymer to extend their lifespan in rat mesenteric blood vessels and detected by fluorescent staining.

Measurement of RBC deformation and velocity in capillaries in vivo.

Red blood cells (RBC) become deformed while flowing through capillaries. We captured images of blood flow in capillaries and of RBC in the rat mesentery using a high-speed camera at 2000 frames/s and then directly measured and estimated the deformation and velocity of RBC in a non-uniform capillary. The distribution of the capillary diameter was determined by image processing.

Effects of carpronium chloride on the microvascular blood flow in rat mesentery using intravital videomicroscopy.

Carpronium chloride, a hair growth reagent, is known to have a vasodilatory action, but its direct effect on the microcirculation has been known very primitively. This study was aimed to examine its effects on the vascular smooth muscles and blood flow in rat mesenteric arterioles using intravital videomicroscopy. After topically applying carpronium chloride on the microvasculature, we measured changes of diameter and blood flow in the arterioles.

Measurement of red cell velocity in microvessels using particle image velocimetry (PIV).

A new technique using particle image velocimetry (PIV) has been developed to evaluate the detailed velocity profiles of red cells flowing in microvessels. The microcirculation in rat mesentery was directly observed using high-speed videomicroscopy, and the images of red cells flowing in the mesenteric arterioles were recorded simultaneously with the arterial blood pressure. Based on the high-speed videomicroscopic images obtained, velocity vectors in single or branched arterioles were evaluated to obtain velocity profiles across the cross-section of arterioles.