We tried to prepare HBV (hepatitis B virus)-free modified hemoglobin (PEG-PLP-Hb) solutions from HBV positive blood. The amount of HBV-DNA and HB antigens were monitored at each washing process and preparation step of PEG-PLP-Hb. The HBV markers were strikingly decreased after washing red cells four times with physiological saline at 1, 700×g for 10min. Although hemolysate contained a small amount of HBV-DNA, more than 99 percent of HBV-DNA were washed out. A residual amount of HBV-DNA left in hemolysate became below the detectable level at the SFH (stroma-free hemoglobin) preparation. In order to obtain a safer SFH preparation, we tested whether Dane particles can be removed by a micro-porous cellulose hollow fiber, BMM (Bemberg Microporous Membrane). A SFH preparation containing Dane particles was filtrated through the BMM-30 (30nm pore size). More than 86 percent of proteins were recovered in the filtrated fractions, whereas Dane particles were left in the concentrated fraction and became below detectable level in the filtrated fractions. Dane particles can be effectively removed by the BMM filter to less than 0.1 percent of the initial amount. The results seem to indicate that contamination of Dane particles in hemoglobin preparations can be avoided to a considerable degree by repeated red cell washing, removal of stroma and BMM filtration of hemoglobin preparation.

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A high water content polyvinyl alcohol hydrogel (85-90% water content; PVA-H) invented by Nanbu has characteristics similar to rubber and causes minimum inflammatory reactions to tissues. A tracheal prosthesis has been fabricated from the PVA-H of 90% water content. The prosthesis, modified from our original one, has three teflon rings so as to keep the tube lumen when implanted. The teflon rings, glued to both ends of the prosthesis, also served as suture cuffs. The cervical trachea was replaced with the prosthesis in 14 adult mongrel dogs. Animals survived from 7 to 120 days after implantation, including 3 sacrificed on postoperative days 43, 51 and 120. All eleven dogs surviving longer than 30 days showed anastomotic disruption to various degrees. The PVA-H tracheal prosthesis showed an adequate consistency and elasticity, air-tight lumen (or air-tightness) and minimum tissue reactions. Long-term fixation of the prosthesis to trachea, however, was difficult. It was concluded that the PVA-H tracheal prosthesis has suitable characteristics as a tracheal substitute, but further improvements to the suture ring and a means of fixation are mandatory.

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In plasma collection from donors, a rotating cylindrical membrane plasmaseparator has attracted special interest recently because of its high efficiency in filtration flux. However, the device has a defect of reducing platelet aggregability due to Taylor vortex flow triggered by the rotation of inner cylinder. In order to establish a blood compatible donor plasmapheresis system, we developed ROMPS and evaluated its performance in in vitro. This device consists of a rotating cone of small angle (1°) and a Nuclepore polycarbonate membrane (0.8μm pore diameter). The rotation of the cone induces high shear rate on the blood without occurring turbulent flow and prevents the concentration polarization formed by blood cells. The observed maximum plasma filtration flux was 0.19ml/min-cm₂ under the condition of an inlet blood flow rate of 50ml/min and shear rate of 6, 000s_-1. The recoveries of F VIII and IX were greater than 95%, and complement activation was not detected. Further, there was no damage to the blood cells, especially the platelet aggregability almost kept constant. We conclude that ROMPS is highly efficient in flux and superior to the cylindrical membrane plasmaseparator in blood compatibility.

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From July, 1978, to December, 1986, the St. Jude Medical valve prostheses were implanted in 814 adult patients. {Aortic valve replacement (AVR): 244, mitral valve replacement (MVR): 428, aortic and mitral valve replacement (DVR): 142}. Operative mortality was 4.5% in AVR, 3.5% in MVR and 6.3% in DVR. The actuarial survival rate at nine years was 81.7% in AVR and 90.9% in MVR. At eight years, it was 91.5% in DVR. The number of valve-related complications was as follows: structural failure (0), thrombosis (AVR 1, MVR 1), thromboembolism (AVR 10, 1.35%/pt-yr), MVR (22, 1.60%/pt-yr), DVR (4, 1.42%/pt-yr), anticoagulant-related hemorrhage (MVR 1), prosthetic valve endocarditis (AVR 2, MVR 1), hemolysis (MVR 4, DVR 1). Reoperation was performed in 8 patients with MVR and 1 patient with DVR. Judging from our nine years of experience, we have concluded that the St. Jude Medical valve is one of the prostheses of our choice.

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