We manufactured portable water purification apparatus for peritoneal dialysate and evaluated it basically. It weighs 6.7kg and is too small to be put in the attache case for carrying. In this apparatus, tap water is purified in aseptic and non-pyrogenic state with ion exchange resin and ultrafiltration filter of hollow fiber type (polypropylene membrane), and then is mixed with concentrated dialysate.
Ultrafiltration was performed only by the negative pressure generated in suppling water. UFR was about 1L/min in 2kg/cm². Tap water was deionized from 200 to 0.1-1.0μV/cm in electric conductivity with ion exchange resin. Treated water proved to be safe qualitatively and bacteriologically.
We will be able to perform clinical trial in the near future.

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An analysis of middle molecular substances in the dialysate of continuous ambulatory peritoneal dialysis was performed and was compared with hemodialysis and hemofiltration fluids. The analysis was done with gel chromatography on Sephadex G-15 and reversed-phase chromatography using μ Bondapak CN, μ Bondapak C₁₈ and Nucleosil 5 C₁₈. The Comparison of middle molecular fractions of gel chromatography of hemodialysis, hemofiltration and continuous ambulatory peritoneal dialysis revealed continuous ambulatory peritoneal dialysis to have the highest value. Middle molecular fractions, a, b, c, and d obtained by gel chromatography were separated into at least 100 peaks by reversed-phase chromatography. In the samples thus obtained, fluorometric detection of peptides was performed by reacting o-phthalaldehyde with primary amine of peptides by post-column technique and approximately 35 peptide peaks were detected.

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Since January of 1980 through June of 1981, 44 uremic patients including 25 males and 19 females had been maintained on continuous ambulatory peritonal dialysis (CAPD) at six facilities in Japan. Total experience was 1772 patient weeks (mean: 40.3±S. D. 20.2, range: 8-75). Dropped out cases were 8; one due to recurrent peritonitis, one due to poor technique, six died of infection, cardiac failure and hepatic failure. An overall incidence of one episode was 12.3 patient months. Twenty seven case (61.5%) experienced no peritonitis. BUN level was 55.5±13.0mg/dl, serum creatinine 10.0±3.5mg/dl hematocrit 27.5±5.6%, and total protein 6.9±6.9g/dl. Thus, clinical trial of CAPD in this country has successfully done.
It is an urgent need to be admitted into health insurance system for reduction of dialysis cost and better rehabilitation of uremic patients.

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From the beginning of 1970, automated reinfusion device has been developed in the treatment of intractable ascites associated with liver cirhosis.
Rhodiascit system without filter was disadvantageous because malignant cells and bacteria weren't removed from ascitic fluid.
We developed new system which used the cellulose acetate hollow fiber as filter. In addition to it, we invented a roller-pump with regulator to operate within safe pressure limit, and a protein sensor to regulate the concentrate protein level. Our new Device has been satisfactorily applied to 105 cases of intractable ascites.
The automated reinfusion system with filter is safe and effective. It is expected to use widely in the treatment for intractable ascites.

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We have experienced 72 cases of pace maker implantation in last 3 years. In 65 of these cases programmable pace maker (rate programmable PM 18, multi —programmable PM 47) were used. Twenty of implanted programmable PM (30.8%) were programmed in chronic stage, because these patients complained palpitation, dyspnea on exertion or fainting. Rate was programmed in 13 cases, sensitivity in 7, pulse width in 3 and hysteresis rate in 1. The symptoms were improved by programming.

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During the period of September, 1973 to October, 1981, we implanted 146 pacemakers to 115 patients. Among them, since July, 1978 36 patients were implanted programmable pacemaker. They were ranged in age from 3 to 91 years old, mean age 65.5.
We have changed the pacing rate in 15, the out put or puls width in 12, the sensitivity in 2, the refractory period in one and hystersis in 9 patients.
We consider that programmable pacemaker are more useful than nonprogrammable type, and multiprogrammable pacemaker is more helpful in every patients.

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Since 1974, 159 programmable pulse generators (53 rate only PPG, 106 rate and output PPG) and 98 multiprogrammable pulse generators have been implanted in 189 patients with symptomatic bradyarrhythmia, ranging in age from 9 to 90 (mean age 61.2).
The rate programs have been performed for the purpose of hemodynamic improvement, clinical condition, reduction of the complaints induced by artificial pacing, and clinical examination.
The hysteresis programmability was available for the maintenance of A-V synchrony.
The hysteresis interval should be programmed over the rate of 55 per minute, because if the A-V synchrony was mainteined, the rate-output curve shaped the plateau over 55 PPM in our investigations

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We made out a cardiac pacemaker so designed that a weak AC signal of less than several 10 microamperes is applied directly to the surface of the living body, a good conductor, that the signal is detected remote from the site of electric application in the same living body and that the frequency of stimulation can be changed in accordance with the instructions of the input signal and used it in an animal experiment.
Using adult dogs under anesthesia with pentobarbital, a catheter type of electrode for the pacemaker was introduced into the right ventricle and an electrode for detecting the signal was embedded in the chest subcutaneously.
On the other hand, an experiment was conducted in which the control signal is applied topically from the right wrist to remotely control the frequency of stimulation.
As a result, it was confirmed that the frequency of stimulation could be changed by a weak signal of less than 10 microampere.
The method using the living body as a direct transmission route for electric signals is suitable for controlling the complex programs and can possibly be applied not only to the cardiac pacemaker but to other artificial organs as well.

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56 unipolar VVI pacemakers were tested by 4 ways of inhibition test—hand grip, back strength, sitting up and push up test. Filter characteristics of Siemens-Elema 668 generator was examined by sin² pulse wave.
Pacemaker inhibition was observed in 34 of 56 (60.7%). Among 4 tests, inhibition occurred most frequent in push up test related to a great pectral muscle and less frequent in the patients with the generators in an abdominal wall as compared with a great pectral muscle area.
Suggestions for avoidance of myopotential inhibition are as follows: (1) Pulse generators which are more sensitive than 1.5mV should not be used unless there is a specific problem. (2) A pulse generator should be placed in a subcutaneous abdominal wall pocket. ()Usage of a bipolar system. (4) Convert to a fixed rate or a ventricular synchronous unit. (5) Usage of a multiprogrammable pacemaker.

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The RS4 pacemaker system, employs a tripolar single lead, can be programmed to operate as an atrial sensing, ventricular pacing pulse generajor (RS mode, VDD), or as a normal demand unit (VVI). In the RS mode, the pacinq rate can vary from 63ppm to 120ppm, depending on atrial activity. We used the system with 3 patients (far-advanced AV block; 1, 3rd degree AV block; 2). P wave amplitude measured by the bipolar floating atrial electrodes were from 2.7mV to 3.0mV. The pacing rate varied in response to exercise and a drug. In the points of double product and cardiac output, RS mode was recongnized to be physiologic rather than VVI pacing.

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P wave sensing was studied with epicard and endocardial amplitude mapping all over the atrium in 8 dogs. The amplitude recorded from the right atrial appendage was very low compared to free wall of both atrium. So J shaped electrode in the right atrial appendage was not adequate for P wave sensing. The maximum amplitude was taken from left atrial free wall. However if this site was chosen, thoracotomy was needed. On the contrary, Fujiwara's method was thought to be able to provide excellent amplitude from right atrial free wall without thoracotomy.

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The result of EPTFE graft implantation to small arteries is not so good, particularly, when the arteries have bad run off.
We implanted inner diameter 5mm EPTFE grafts to bilateral femoral arteries of 20 mongrel dogs and made the bad run off by restriction of the distal blood flow on one side. After 1 hour, the implanted grafts of 5 dogs were examined by scanning microscope and the platelets adhered to the surface were counted. After 3 months, the implanted grafts of 15 dogs were examined the patency and intimal hyperplasia.
The decrease of the distal blood flow had the platelet adhesion increased and the early thrombus formation occluded the grafts. In the grafts patent 3 months after implantation, intimal hyperplasia was thick when the distal blood flow was low. This is explained by platelet facter that stimulates the smooth muscle cell to migrate and proliferate.

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Despite the widespred clinical use of polytetrafluoroethylene (PTFE) grafts, few reports dealing with their mechanical conection of graft organization have appeared in the liturature. 6 PTFE grafts and 6 DeBakey vascular-D grafts were implanted into the aorta of 6 mongrel dogs using absorbable sutur (Dexon®).
The strength and adherence of graft organization at the vascular prosthetic anastomotic site were measured after 118 to 149 post operative days. The strength of PTFE graft anastomosis was 98.5% and the on of DeBakey vascular-D graft anastomosis was 93.18%. The adherence of graft organization was 1.28kg/0.5cm² on PTFE graft and 1.37kg/0.5cm² on DeBakey vascular-D graft. The result indicates that the implanted PTFE graft has good affinity biomechanically.

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In an experience with 56 small arterial reconstructions using Biograft, we consider that the pannus hyperplasia at the anastomotic site is the main cause of graft failure occurring in the intermediate period (6 months to 2 years) and likely due to compliance mismatch and abnormality of the anastomotic geometry. We previously reported that host artery at the anastomotic site is most seriously affected by compliance mismatch and the influence of compliance mismatch is amplified by abnormality of anastotic geometry. This report describes an effectiveness of fixation of the anastomotic host artery using Teflon ring and or AronAlpha in order to prevent intimal hyperplasia. Twenty two grafts of EPTFE with a diameter of 4mm, were plased in the carotid arteries of 11 dogs. Follow up ranges from 4 to 16 weeks. Twenty-two grafts were devided into 3 groups. Group 1; control, 11 grafts. Group 2; 6 grafts. Host arteries at the anastomotic sites were fixed with Teflon rings. Group 3; 5 grafts. Host artery were stabilized with AronAlpha. Group 1 patency at 4 weeks were 70%, Group 2 50%, Group 3 80%. Of 11 grafts of control gourp, 2 patent grafts were demonstrated obvious intimal hyperplasia of host artery at the proximal anastomotic site at 4 and 12 weeks after implantation, respectively. Of the total 22 grafts, 12 grafts showed good anastomotic geometry and remainder showed poor. The anastomotic geometry were graded as good to poor by our angiographic criteria. The good geometry group patency at 4 weeks was 83.3%, poor geometry group 44.4%. We have concluded that anastomotic geometry is the most important factor influencing the early results and, when anastomotic geometry is satisfactory, failures occurring in the intermediate period are mainly caused by intimal hyperplasia due to compliance mismatch, and which is minimized by the fixation of the host artery at the anastomotic site.

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A role of fibrin on healing process of an expanded polytetrafluoroethylene graft implanted in the inferior vena cava of dogs defibrinogenated with a snake venom, batroxobin, was studied by light and electron microscopy.
In spite of reducing the fibrinogen level to unmeasurable levels after 3 days, there was no obvious difference in the process of pseudointimal formation between the moderately defibrinogenated dogs and the controls. In the severely defibrinogenated dogs, pseudointimal reorganization and endothelial cell invasion were interefered with for only the first 3 weeks. The structural difference of the initial mural thrombus resulting from reduced fibrin formation might be a major factor influencing the pseudointimal formation.

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In order to study the blood compatibility and tissue compatibility of fibrin membrane, vascular prostheses with human fibrin, fibrinimmobilized prostheses, were implanted in subcutaneous tissue and abdominal aorta in canine.
The results were as follows.
1) Human fibrin suggested no antigenecity to canine.
2) Fibrin-immobilized prostheses implanted subcutaneously showed good tissue healing, comparing with non-treated Double Velour Knitted Dacron. This is realized in the biochemical investigation; that is, the uronic acid in surrounding tissue of fibrinimmobilized prostheses showed the tendency to decrease in the period of implantation.
3) In the replacement of canine abdominal aorta, good tissue incorporation or healing of fibrin-immobilized prostheses were also seen 24 weeks after implantation.
4) Preclotting vascular prostheses with fibrin is good method not only to prevent hemorrhage through prosthetic wall at the time of operation but also to modify tissue healing of the prosthetic graft.

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Expanded Polytetrafluoroethylene grafts (internal diameter: 4mm, length: 20mm) were implanted in the external iliac arteries of dogs to investigate the effects of absorption of water solutions in E-PTFE grafts. One month after implantation, dogs were sacrificed to harvest the grafts. The saline solution absorbed graft and the heparin solution absorbed graft indicated good patency rate in comparison with the graft with no treatment. The heparin solution absorbed graft had the best antithrornbogenicity.

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The less than ideal clinical results in reconstruction of small sized artery mandate thorough consideration of the role played by different factors involved in arterial graft thrombosis.
This study suggests the importance of matched physical property between the graft and host vessel especially at the anastomotic site.
Various vascular prostheses of 4m internal diameter and 6cm length were implanted in canine carotid artery.
It was very interesting to note the patency rates of the grafts 3 weeks after implantation: the patency rates in the group of smooth inner surface (e-PTFE, Preserved human umbilical artery, HEMA/Acetylchitin/Poly-γ
-BzI-L-GIu coated non-woven polypropylene) were limited between ON 38%, in contrast with this in the group of the graft with rough inner surface (Non-woven polypropylene, Double velour knitted dacron-Crimp and Noncrimp) more than 60% were patent.
Failure of these grafts often resulted from thrombus at the sites of anastomotis.
From these results the authors devised new method to treat the arterial wall near the anastomotic sites. The host artery near the anastomotic line was treated by 0.65% GA, in order to alleviate the compliance mismatch between the graft and host artery and to prevent the release of coagulant factors from the arterial wall.
Using this method the patency rate of e-PTFE graft was improved up to 60% 3 weeks after implantation, and this is significantly better compareT.ng with the results of GA non-treated a-PTFE grafting.

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A retrospective study of 135 patients with synthetic arterial grafts was made. Anastomotic false aneurysms occurred 8.2% in patients who were successfully implanted synthetic grafts in our clinic since 1964. The occurrence in patients those were sutured with silk was in 19.2% being much higher than that of patients sutured with Dacron materials.
Infection of synthetic grafts occurred 4.4%. It was a serious and life-threatening complication.
The incidence of infection was significantly increased when the anastomosis was performed through a groin incision.
Occlusion of grafts occurred in 6.7% but the conservative treatment was done in most of chronic cases.

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Thirty-seven Gore-Tex grafts were implanted for bypass to twenty-nine cases of arterial occlusion_ of lower extremities.
For the long and diffuse arterial obstruction, which were found in eight cases among twenty seven ASO cases, "two-step bypass" procedure were performed.
"Two-step bypasses" are patent in six cases, and occluded in two cases, which showed severely poor distal run-off.
There are three type bypasses in "below-kree bypass" procedure, bypass to distal popliteal artery, to tibio peroneal trunk and to anterion tibi al artery.
"Below-kree bypases" are patent in f owr cases and occluded in three cases, which showed poor distal run-off.
There are no severe complications of-Gore-Tex grafts in twenty-nine cases of arterial occlusion of lower extremities.

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Since January 1980 to August '81, we have been used 37 PTFE grafts in 26 cases, 29 grafts for femoro-popliteal (F-P) bypass, 3 for vascular access, 2 for aorto-remal bypass, 2 for carotid-brachial bypass and 1 for axillofemoral bypass. 24 patients were men. There were two hospital death and no late death. All of them died from acute renal failare.
Of the 29 grafts using F-P bypass, 23 grafts were patent (79%). Among the 6 grafts having occluded, 5 occurred within 12 months. Graft flow, angiographic distal run off and indication of surgery were seemed to affect graft patency. All two grafts in TAO were occluded in spite of good distal run off. Vessel access were all occluded within 3 months. Aortorenal bypass is patent 14 months after operation. Aorto-brachial bypass is patent 9 months after reoperation, which did thrombectomy and patch plasty of the distal anastomosis immediatry after graft occlusion.
From our several experiences of reoperation in PTFE graft occlusion, the raft seemed to occlude by narrowing in distal anastomosis, which caused from panus formation. There were minimal change in proximal anastomosis. So, we recently attempt to add saphenous vein patch at distal anastomosis to decrease panus formation.

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We have experienced 140 patients with Swine Graft, 150 patients with Gore Tex Graft, and 48 patients with mobilized Bacilic vein fistula.
Patencies in 4 years function were 17 percent in Swine Graft, 21 percent in Gore Tex Graft and 54 percent in mobilized Bacilic vein fistula. Complications of grafts were pseudovalve formation, stenosis of puncture site, progressive narrowing of efferent vein and false aneurysm formation. In order to prevent graft complications, especially pseudovalve formation or false aneurysm formations, It is very important to control blood pressure of the patient, and to decrease ultrafiltration rate during hemodialysis.

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Reconstruction of the large vein is more difficult than that of the great artery. Tubular grafts of Gore-tex with pore size of 30-μ have been used in 5 patients for reconstruction of large vein since last two years. Four patients (case I-4) had mediastinal tumor, and the other one (case 5) had the obstruction of the inferior vena cava (IVC) in hepatic region. Malignant thymoma was histologically proved in three cases (case I, 2, 3). Poorly differentiated epidermoid carcinoma was found in one case (case4).
Superior vena cava (SVC) was partially resected and patch angioplasty was done by Gore-tex in easel. SVC was resected and replaced by Gore-tex in case 2. The left innominate vein was resected and the reconstruction was done between the innominate vein and the right atrium (RA) in case 3. In case4, the tumor was unresectable and the bypass grafting was performed between SVC and RA. In case 5 with IVC obstruction, resection was not accomplished, bypass grafting was done between RA and IVC to keep the blood flow of left hepatic vein located just above the site of obstruction.
Mean follow up was 9.5 months in all patients. Except for one case (case 4) with epidermoid carcinoma, four patients (case I, 2, 3, 5) were doing well in post operative course. Venog raphy was performed in 4 patients (case I, 2, 4, 5) after venous reconstruction. Patency of the Gore-tex graft was confirmed in case I and 2 with mediastinal tumors, and in.case 5 with IVC obstruction. Occlusion of the graft was confirmed in case 4.Heparin and Warfarin, as an anticoagulant therapy, were used and thrombotest was maintained in 30-50%. It could be concluded that Gore-tex graft was useful material to make reconstruction of the large vein.

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Hemodynamic and biological properties of prosthetic valves were evaluated using pulse duplicator, whole-body simulator and through clinical follow up of the patients. Duplicating test revealed the inherent characteristics; durability, opening characteristics, frequency response, regurgitation and so on. Effective characteristics of various combinations of valves and sizes were analyzed using hydrodynamic simulation. Follow up of the patients gives available information of biological properties of prostheses,
Through these evaluations, mechanical valves; Bjork-Shi ley, St. Jude Medical and Omniscience; became the prostheses of our choice instead of stented xenograft. Effective co-operation between the experimental labolatory and clinical department is necessary for evaluation of prosthetic valve properties.

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Between 1964 and 1981, 380 valve replacements were carried out in our institute. Of the 380, 285 operative survivors, which consisted of 166 isolated MVR, 88 isolated AVR and 31 A+MVR were analyzed by means of actuarial method. Hemodynamic studies were also carried out during late follow up period. In MVR, survival and event free proportins were significantly low in Kay-Shiley (KS) valves. Poor results were also obtained in Starr-Edwards (SE) 6500 valves. Severe thromboembolic complication and calcification were noted each in one case among 30 cases with xenograft valves. In AVR, there were slight differences in actuarial survival curves between several types of prosthesis. But event free proportions were significantly low in SE 2310/2320 valves, because of severe hemolysis and intermittently stuck ball. In hemodynamic study, Björk-Shiley (BS) valve showed excellent results both in MVR and AVR.
It is concluded from this study, that BS valve would be a prosthesis of choice in both mitral and aortic positions.

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Based of our 20 years clinical experience with 647 valve replacements, Lillehei-Kaster prosthetic valve for aortic position and bioprosthesis for mitral position are exclusively used in this institution at the present time. The hemodynamic studies of prosthetic valve function were performed in the patients who had MVR with bioprosthesis and AVR with Lillehei-Kaster prosthesis. The present study indicates that the patients who had both MVR with bioprosthesis and AVR with mechanical valve still have the mild stenotic valve condition, although their cardiac function much improved postoperatively. The further investigation should be performed to make ideal prosthetic valve having large effective valve orifice and long-term durability.

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Advantage of ISPX
I. ISPX has superior hydrodynamic characteristics almost equivalent tc the best of mechanical valves.
II. Postoperative hemodynamic evaluation indicates that ISPX presents significantly better performance than Hancock Xenograft in CUSP Opening, pressure gradient and valve area.
III. The excellent hemodynamic characteristics of ISPX appears to be particularly in Smaller Size.
IV. There has been no structural failure and thromboembolic complication during 1220 patient months follow-up.
Disadvantage of ISPX
I. A consistent relationsnships between each size of valve and pressure gradient or valve area Could not obtained.
II. The incidence of PVE of 3.93% per patient year oecured and 2 patients were lost in late follow-up. Extremely careful attension for possible infection is mandatory.

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Postoperative functions of porcine xenograft (XG) (Carpentier-Edwards) in patients (pts) and pericardial XG (Ionescu-Shiley) in 5 pts were evaluated an average of 13 months after mitral valve replacement. Hemodynamic and cineangiographic investigations were performed to assess left ventricular (LV) functions and to see the movements of the XG leaflets on axial view.
1) Incomplete opening of the porcine XG in mitral position was related to the postoperative LV function. In pts with poor LV function, decreased mitral valvular flow was obligated to open incompletely the leaflet of the XG, and apical leaflet of the XG was tend to be affected and form a thrombus firstly.
2) Pericardial XG showed good movement about one year after mitral valve replacement.
3) We now consider that mechanical prosthesis has simple movement, which will not be affected by post-operative hemodynamics, and it is preferable to use tilting valve in mitral position under well-controlled anticoagulant therapy.

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The 2nd Department of Surgery. Nihon University School of Medicine
Since October 1963, artificial valve prosthesis, which is Starr-Edwards, Xenograft and St. Jude Medical valve prosthesis has been used for cardiae valve replacement in a series of valvular disease in our Nihon university hospital.
There is no ideal artificial cardiac valve as the normal human valve. St. Jude Medical valve with their central flow orifice have provided fine valvular functions and, in contrast to other mechanical artificial valvular prosthesis, have caused no significant hemolysis. Lifewise, St. Jude mechanical valves have not caused other abnormal vital reactions.
Therefore, St. Jude Medical valve prosthesis, with its advantage of durability, least hemolysis and hemodynamic quality, may be anticipated to move of salient in the management of valve disorders.

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The artificial heart pump valves should be chosen different decision standards from cardiac valve prosthesis. Today, new generation of rationalized cardiac valve prostheses were introduced to artificial heart pump, but many of the valves were doubted their durability, inadequate hydro-dynamical response and expensiveness. The target of the work is to develop new adequate testing method for artificial heart pump valves and evaluate a few commercial available cardiac valve prosthesis.
Tested valves were installed in the artificial heart pump in situ and mounted to a mock circulation. Bjork-Shiley, Lillehei-Caster, Omniscience, St-Jude Medical, and Hall-Caster of 18mm measured diameter of orifice were tested. On a plain of pressure-gradient vs flow, valve-Lissajous' figure were recorded on various driving parameters and analysed.

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Since 1960 When Dr. D. Harken successfully implanted a ball valve in aortic position, 20 years has gone by and valve replacement surgery became a standard surgical field. During this period various changes took place as to valve substitute. Retrograde analysis of the valve substitutes in Japan was attempted to find a way how they should be in future as to durability and thromboemboligenecity in regards to tissue valves versus mechanical valves.

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Biomaterials are fundamental components in artificial organs. For developing the ideal type of artificial organ, “HOMEOSTAT, ” that is composed of sensor, processor and effector and forms the closed feedback loop with the physiological mechanisms of human body and is capable of adjusting the disturbed homeostasis of diseased living body in real time, the functional biomaterials should be designed intentionally.
The author has insisted that the Biomaterials Chemistry is important where the interaction between materials and living systems should be explored at the molecular level. On the basis of Biomaterials Chemistry, the tailormade biomaterials could promote the composite functional artificial organs in the future.

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Major goal of Biomedical Engineering is the development and improvement of diagnostic and therapeutic tools of health care to optimize their effectiveness, reliability, safety and overall benefit. In other words, Biomedical Engineering is defined as the maximal contribution to welfare of patients with minimal cost and risk. Although effective function of artificial organs has so far been a major concern in their research and development, very little is known about the path-physiological effects of artificial organs on bodies, which has very often arrested their rapid progress. Reliability and cost effectiveness have also been shelved so far, while these two factors have been most important in the field of engineering. Biomedical Engineering should contribute much to Artificial Organs in these three points.

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Perfluorochemical emulsion (Fluosol-DA)was used as blood substitutes in acute massive bleeding patients, priming solution for extracorporeal circulation in calves, and perfusate for cadaveric abdominal organ perfusion for renal transplantation.

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An artificial esophagus was made of 5cm of silicone rubber tube covered with dacron mesh.
Sixteen dogs were implanted with this artificial graft in the defect of thoracic esophagus using of 3 different anastomotic methods, i . e . simple end-to-end anastomosis, end-to-end anastomosis with two layer suture and over layer end-to-end anastomosis with flanges.
Seven of 16 dogs (44%) survived for more than 12 months without any complication, and four of them have prolonged survival time more than 6years.
In 6 of 7 prolonged survived dogs, regurgitation of the graft was recognized in the period from 3rd to 6th month after operation.
Esophageal stenosis slightly increased during 6 month after regurgitation of the graft, but did not advance more seriously than that time condition till their death.
In these cases, the mucosal regeneration of the esophagus on the grafted portion was almost completely recognized with macro-and micro-scopical observation.
On the other hand, there was no difference among the anastomotic methods for the prognosis of experimented dogs.
These results stggest that this artificial esophagus has a possibility for clinical trials in the future.

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Since 1978, 46 patients, ages 1-78yr. who required long-term maintenance of nutrition parenterally, were placed on a program of an artificial gut system consisting of infusion bag, ivline, and continuous infusion pump combined within the special jacket for periods ranging 1 to 434 days. This artificial gut system was safe and effective for maintaining an optimal nutritional status, and was valuable not only in allowing more freedom and ambulation in hospitalized patients, but also in permitting them to resume a nearly normal life at home.

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Our originally developed bedside-type artificial endocrine pancreas system enables the perfect glycemic normalization in diabetics against various stimulations on moment-to-moment basis. However, the size of the device and the vascular access for glucose monitoring make the long-term clinical uses difficult. A needle-type glucose sensor consisted of immobilized glucose oxidase and the electrode, has been developed as the breakthrough for the completion of the wearable-type artificial endocrine pancreas. The successful blood glucose control in depancreatized dogs with this device suggested the feasibility of this closed-loop control system in long-term clinical applications.

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A single clinical application of the use of polytetrafluoroethylene and some discussions were presented in this report.
Case report is followed; A 57 yearold house wife, who was operated for gastric cancer five years ago, was admitted because of general fatigue and oligulia. Laboratory data showed BUN 33.7mg/dl and s-Cr 3.2mg/dl. Excreatory urography demonstrated right hydronephrosis and left dysfunctioning kidney. Retrograde pyelography showed bilateral middle third of ureter narrowing about 12cm in length. Under diagnosis of gastric cancer invasion in retroperitoneal space, right nephrostomy and pelvi-vesical bypass operation using polytetrafluoroethylene (Gore-Tex®, φ6mm) were performed. Although nephrostomy was clumped on 8th postoperative day, there was no episode of fever or lumbago, so nephrostomy was removed after confirming remarkable recovery of hydronephrosis. Vesicoureteral ref lux was demonstrated by cystogram and mictional cystogram on 36th postoperative day, but there was no symptoms and signs as pyelonephritis. A fifth months' excreatory urography and laboratory data were normal.

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The first case of single channel Cochlear Implant in Japan was reported. This case was a 56 year—old male with bilateral profound hearing loss caused by labyrinthitis which was affected by meningitis 36 years ago A diagnosis of sensory deaf was carried out by electrical promontory testing (E.P.T.). An internal induction coil was fitted by surgical procedure on Dec. 3. 1980 and the first electrical stimulation was performed on Feb. 3, 1981. As a result of our first experience of single channel Cochlear Implant, Cochlear Implant is one of the useful approach to restore the deaf peoples.

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The permeability characteristic was studied of different types of hollow fiber plasma separators including polyvinylalcohol (PVA), cellulose acetate (CA), polysulfon (PS) and polypropylene (PP). PVA and CA were found to be superior in the separation of canine plasma; 2.5-3.0 1/hr/m² at a blood flow rate of 150ml/min.
The permeability of PVA was then studied according to the length-diameter ratio, structure of the surface and hydrophilic degree of the membrane in order to find an optimum condition of the plasma separator.
Best sieving coefficient was found with a hydrophilic PVA having a smooth surface and a pore size of 0.4μm.
A precise kinetic study along with this line is under way.

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In an attempt to niminize an amount of replacement fluid, double filtration plasmapheresis in which larger molecules are discarded after selective concentration has been devised and clinically applied. Selectivity in concentration performance is analyzed. Sieving coefficient of the plasma separator is very much dependent upon a size of molecules, namely, the larger the molecualar size is, the smaller is sieving coefficient present. On the other hand, larger molecules show larger concentration coefficient by the plasma filter. Consequently, pathogenic factors of larger molecules are selectively and effectively removed.

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In order to provide a fundamental sup support for continuous cryofiltration (CCF), experiments on cryoprecipitation in vitro with immunochemical analysis on four RA patients were carried out. 1) Incubation of the fresh plasma from RA patients revealed clear precipitate at OC and it increased on time course. 2) Possible role of complement on cryoprecipitation was suggested, becouse addition of fresh normal human sera on the inactivated RA sera facilitate the cryoprecipitate, which was less than th that of RA plasma.
3&Immunochemical analysis of the cryoprecipitate eluted from filters revealed that it was consisted of IgG, IgM, IgA and fibrinogen, contained much immune complex of each Ig class and high RE titer.

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