Akimasa Kouno

Learn More
To obtain a physiological response by a total artificial heart (TAH), while eliminating the hemodynamic abnormalities commonly observed with its use, we proposed the use of a conductance- and arterial pressure-based method (1/R control) to determine TAH cardiac output. In this study, we endeavored to make use of a variable more closely tied to central(More)
The undulation pump total artificial heart (UPTAH) is a small implantable total artificial heart. As the UPTAH generates outflow and inflow at the same time, control of the UPTAH is very difficult. Therefore suitable control methods specifically for the UPTAH should be established. Various motor control, left-right flow balance control, and physiological(More)
A highly sensitive HPLC method for the determination of prolyl dipeptides, Pro and Hyp in serum was developed. After deproteinization of serum and pretreatment with o-phthalaldehyde, the analytes were derivatized with 4-(5,6-dimethoxy-2-phthalimidinyl)-2-methoxyphenylsulfonyl chloride at 70 degrees C for 10 min. The fluorescent derivatives of prolyl(More)
The influence of repeated hypoxia on the development of haemoglobin (Hb) subtypes and on extramedullary haematopoiesis (EMH) was investigated in young Wistar rats of different ages. The rats were exposed to hypercapnic/hypoxic and to “simple” hypoxic conditions. The results obtained were compared to those of an untreated age-matched control group. Different(More)
The undulation pump is a small size continuous flow displacement type blood pump that has been developed for an artificial heart. Using undulation pumps, 2 types of implantable total artificial hearts (TAHs), the undulation pump TAH (UPTAH) type 1 (UPTAH 1) and UPTAH type 2 (UPTAH 2) were developed. Both UPTAHs were designed to be small enough to implant(More)
A practical model (Model-1) of a jellyfish valve was developed, which was composed of a valve seat and a flexible membrane. The valve seat has 12 spokes to hold the membrane, and is made of solution-cast polyurethane coated with segmented polyurethane or Cardiothane. The flexible membrane is 200 microns thick, and made of segmented polyurethane or(More)
For a valve to be fabricated seamlessly into an artificial heart (AH) blood pump, a jellyfish valve has been developed, in which a thin membrane is fixed at the center of a valve seat having several spokes to protect against prolapse of the membrane. The valve is superior in performances to a Björk-Shiley valve, and reveals good blood compatibility. The(More)
Bjork-Shiley and Hall valves used in most artificial heart blood pumps have often induced problems, which include 1) An expensive valve must be used even when the AH is used for only a few days, 2) Ring thrombus was often formed at the interface between the valve ring and blood pump, seamless fabrication was not possible, and 3) Mechanical failure often(More)
The undulation pump (formerly called the precessional displacement pump) is a continuous flow displacement-type blood pump that is being developed as an implantable total artificial heart. A new undulation pump was developed for chronic use and was examined with animal experiment and flow visualization studies. In the animal experiment using a left(More)
A total artificial heart (TAH) goat survived for 360 days on the new automatic control method (1/R control), in which the cardiac output of the TAH can be controlled through the cardiovascular center by making it function by reflecting the beta-adrenergic reaction in peripheral vascular resistance. This is thought to be the only long-term, real-time,(More)