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[in Japanese]
1997 Volume 26 Issue 3 Pages
571
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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Y. MOCHIZUKI, Y. SUGITA, Y. OKAMURA, H. MORI, K. SIMADA
1997 Volume 26 Issue 3 Pages
573-576
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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The number of elderly and critical condition patients who require aortocoronary bypass (A-C bypass) surgery continues to increase, whereas those who require intraaortic balloon pumping (IABP) remains constant. Between 1991-1996, we performed A-C bypass surgery on 244 patients. Of these patients, 49 (20%) required IABP. The direct ascending aortic cannulation technique for IABP insertion was performed on 2 of the 49 cases. Cannulation was performed using two 3-0 polyester braided purse string sutures in regions of lower calcification, following ligation. The patients were weaned from IABP without complications. Therefore, balloon catheter insertion via the ascending aorta appears to be an effective and safe technique for use during A-C bypass. However, in the case of critical condition patients, special attention must be paid postoperative recovery course.
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Toshitaka YASUDA, Nobuko HANDA, Akio FUNAKUBO, Yasuhiro FUKUI
1997 Volume 26 Issue 3 Pages
577-580
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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In our current study, we found that the rate of hemolysis was related to the collision stream (more 300cm/sec) against the inner surface of extra-corporeal circulation devices. In order to estimate the occurrence of collision stream against the inner surface, we made rough surface area in a centrifugal pump. The surface roughness existed near the outlet domain and on the impeller. In addition, the effect of collision stream was estimated from the relationship between the pump rotational speed and the rate of hemolysis. The results of those in-vitro tests were showed as follows. When the pump rotated in low speed, there did not exist the relation between the rate of hemolysis and the surface roughness in an outlet domain and surface of an impeller. On the other hands, when the pump rotated on high speed, we found that the rate of hemolysis increased outlet domain.
In conclusion, the collision stream toward a particular part affected on the rate of hemolysis.
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-Development of Left-Right Indipendent Motor Type and Implantation-
Y ABE, T CHINZEI, T ISOYAMA, T ONO, S MOCHIZUKI, I SAITO, H WAKUI, K M ...
1997 Volume 26 Issue 3 Pages
581-587
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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The undulation pump is a continuous flow displacement-type blood pump aiming to develop a compact total artificial heart (TAH) with high performance. By using undulation pumps, the undulation pump TAH (UPTAH), which had an independent motor for left and right pump, was developed. This new TAH works without any compliance chamber or atrial septal hole. The size of UPTAH could be reduced to 75mm in diameter and 80mm in length. The weight was 650g. The implantation of UPTAH was performed in two goats. UPTAH could be implanted successfully into the goat's chest with good fitting. One of the goats survived for 3 hours and 40 minutes, stood and extubated. UPTAH could resolve the problem of the size for implantation, which was the most important subject for the development of an implantable TAH.
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T. YAMBE, S. NITTA, T. SONOBE, S. KOBAYASHI, S. NAGANUMA, S. NANKA, Y. ...
1997 Volume 26 Issue 3 Pages
588-592
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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For the development of the totally implantable artificial organs, it is an important problem to monitor the conditions of the implantable devices, especially, when used in the clinical cases. In this study, we use the sensors for the 3-dimensional (3-D) virtual reality (VR) system for the monitor of the implantable artificial heart. The position sensors using electro-magnetic forces were attached to the inner actuating part. Sensitivity of the position sensors were the order around 0.8mm at sampling time is 120 point/sec. By the use of these VR position sensors, we could easily detect the position, movement, and pitch, yaw, roll of these sensors. The experimental evaluation using moc circulation loop and healthy adult goats were performed. Experimental results suggest that our newly developed implantable sensors for monitoring the implantable artificial heart system were useful for sensing driving condition, suggesting may be useful for the implantable devices for the clinical usage.
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-COMPARISON BETWEEN α-STAT AND PH-STAT MANAGEMENT-
T. NISHIZAWA, A. USUI, K. YASUURA, T. WATANABE, T. MASEKI, Y. KAWARADA ...
1997 Volume 26 Issue 3 Pages
593-595
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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In order to compare the effect of acid-base management on cerebral blood flow and metabolism during retrograde cerebral perfusion (RCP), we have studied 79 blood gas samples in the α-scat and 16 ones in the pH-stat management from the patients undergoing aortic arch surgery. During retrograde cerebral perfusion at a nasopharyngeal temperature of 20°C, the pump flow was adjusted so that the pressure of the SVC would be maintained around 25mmHg. In the pH-stat management, RCP flow rate was significantly greater and vascular resistance was significantly lower than those in the α-stat management. Lactic acid consumption, lactic and pyruvic acid rate and the glucose consumption showed no significant difference between groups. The pH-stat management revealed lower vascular resistance and greater RCP flow rate than did the α-stat management due to higher PaCO2 levels. The pH-stat management may have some efficacy for the brain circulation and the brain protection. However, the disadvantage of high PaCO2 levels has not been clarified. Further studies will be necessary to refine the standard for RCP management.
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K. DOI, S. SATOH, J. HIRAI, M. ONO, T. EMMOTO, S. TODA, A. SOMA, K. KI ...
1997 Volume 26 Issue 3 Pages
596-600
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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In some clinical cases of aortic arch replacements, unsuccessful retrograde cerebral perfusion (RCP) through conventional caval cannulae occurred, which might be due to an impediment with venous valves at the jugular-subclavian junction as well as due to a steal of perfusion flow through collateral veins. In order to overcome these problems, a new double-lumen catheter was developed. This catheter was designed to be placed in the internal jugular vein (IJV) by percutaneours catheterization using a 14 Fr sheath. A balloon was installed at the tip of catheter for the occlusion of superior versa cava (SVC). Four side holes were opened at 125mm from the tip for blood perfusion into the IVJ. In a mock circulation, the pressure at perfusion line (16-118mmHg) increased with increasing the flow rate (0-400ml/min). No significant hemolysis was observed under continuous flow (400ml/min) for up to 120min. In a clinical study, the inflated balloon effectively occluded SVC, which may be expected to decrease the steal of perfusion flow from the IVJ to the lower half of the body. The distance from the tip of catheter to the side holes should be optimized in future.
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T KOHJIMA, M SHIONO, Y ORIME, K NAKATA, M HATA, A SEZAI, H YAMADA, M I ...
1997 Volume 26 Issue 3 Pages
601-604
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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Comparison study of complete artificial circulation for liver on cardiogenic shock: pulsatile or nonpulsatile? The weaning rate of mechanical circuratoly support on cardiogenic shock has increased, However, survival rate was not satisfactory, because of multiple oregan failure (MOF). The purpose of this study is to estimate the effects of pulsatile and nonpulsatile artificial circulation, to liver microcirculation and function. Cardiogenic shock was made by ligation of left anterior descending branch in pig. As right ventriculer assist device, nonpulsatile pump (Nikkiso HPM-15) was applied. Left ventricule device was supported by nonpulsatile pump (Nikkiso HPM-15) {NP group} or pulsatile pump (Zeon Medical). Both groups drived with equivalent meen aortic pressure for 3 hours. We measured the hepatic artery blood flow, potal vein blood flow and liver regional blood flow. As for metabolic data, GOT, GPT, arterial blood ketone body ratio (AKBR) and lactate/pimbic acid (L/P) were evaluated. The hepatic artery blood flow and potal vein blood flow were no differences between the both groups. However, in the P group, they showed more normal value than that of NP group. The regional blood flow of liver and AKBR, L/P showed significant improvements in P group compared with NP group. These findings suggest that pulsatile circulation may be beneficial for microcirculation of liver.
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N. MOMOSE, T. MAEDA, K. ANDO, M. MATAYOSHI, A. KITAMURA, T. INO
1997 Volume 26 Issue 3 Pages
605-609
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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We developed a novel cardio-pulmonary bypass (CPB) system with independent regulators for the bypass flow and the circulating blood volume. We put a blood reservoir chamber beside the main blood stream line of the pump. It was connected to the blood stream line via a branched line of the venous drainage tube. Using a roller pump attached to this branched line, we regulated the blood reserving volume, which inversely correlated with the blood circulating volume during CPB. We regulated the blood flow using the other roller pump attached to the main blood stream line. Through in vitro experiment using a special air trapping filter (Auto Vent SV Blood Filter
TM), we elucidated that the air bubbles in the drainage tube could be completely eliminated. In clinical trials of 113 CPB cases, we encountered no significant complications. In all of these cases, we could regulate the blood flow and the circulating blood volume independently and safely. In conclusion, our novel CPB system was excellent in regulating the circulatory parameters and conditions precisely during CPB. Moreover, it could provide the possibility of the automatic regulation for CPB management.
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Hiroyuki MORITA, Motoyoshi SATO, Izumi AMANO, Koh NAKATA
1997 Volume 26 Issue 3 Pages
610-612
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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Result of Verotoxinl, 2 absorption test of PMX Fiber Cellulose fiber with polymyxin B showed dose response absorption of endotoxin in vitro. Based on this result, we applied two PMX columns to endotoxemic patients. Hemoperfusions using single PMX columns were applied to 13 patients 18 times. Of these patients, hemoperfusions were applied twice to five individuals. Nine patients were treatedwith two sequential PMX columns (double PMX columns). The multiple organ failure (MOF) scores of both groups were very similar. There was no significant difference in the reduction of serum endotoxin level between single PMX column application and the use of double PMX columns. However, the survival rate of patiens treated with double PMX columns was significantly higher than that of the single PMX column application group. Our clinical trial showed the advantage of double PMX column application. PMX fiber was mixed with verotoxin 1 and 2(VT 1, 2) solution derived from E coli (O 157). PMX fiber did not absorb VT 1 and 2 for 120 minutes.
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K YAMAJI, S YAMANE, Y NIIMI, A SUEOKA, Y NOSÉ
1997 Volume 26 Issue 3 Pages
613-617
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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A stainless steel leukocyte filter has been developed for leukoreduction and immunomodulation. Our group has previously reported the superior efficiency of the filter for leukocyte removal. At this time, biocompatibility of the filter is being evaluated in various categories. These categories include thrombogenicity, complement activation, cytokine production and leukocyte stimulation, etc. In this experiment, thrombogenicity of the filter is evaluated by analyzing adsorbed protein onto the fibers. Furthermore, production of proinflammatory cytokines are being evaluated, including IL-1β, TNF-α, IL-4 and INF-γ. In SDS-PAGE, the protein which has a molecular weight of more than 100 KDa is not detected on the stainless steel fiber. In the western blotting analysis, the amount of albumin, IgG γ chain and fibronectin adsorbed onto the stainless steel fibers is less than those onto the polyester fibers. These results may indicate that the stainless steel is a superior materialfor anti-thrombogenicity compared to the polyester. All of these cytokine levels, IL-1β, TNF-α, IL-4 and INF-γ, were not significantly changed after filtration. These results may indicate that the stainless steel filter has less influence on the production of proinflammatory cytokines. The results of these investigations show, the stainless steel leukocyte filter is potentially a superior device for leukoreduction and immunomodulation.
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Y. HIRAISHI, Y. EZAKI, Y. KOBARAI, A. SUZUKI, T. TANIGAWA, K. FUJITA, ...
1997 Volume 26 Issue 3 Pages
618-623
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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We have developed a new vascular graft, PF-V, consist of polyester knitted fabric tube impregnated with plasmin treated fibrin. We studied the patency and healing properties of PF-V implanted into canine carotid or femoral arteries at 48 months-implantation. The cumulative patency rate of PF-V was 68% after 48 months. The stenosis and the dilation of the grafts were not observed in all cases by angiography. In histlogical study of PF-V, hyperplasia of neointima and calcification were not observed. These results suggest that PF-V may be expected a good patency after long term implantation and applied for peripheral arterial reconstruction.
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H. ADACHI, A. YAMAGUCHI, S. MURATA, H. KAMIO, M. OKADA, A. MIZUHARA, T ...
1997 Volume 26 Issue 3 Pages
624-628
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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New branched sealed Dacron grafts were used in 14 patients for the replacement of aortic arch aneurysms. This graft was consisted of the major graft (24mm or 26mm or 28mm) with 3 branches (10mm+8mm+8mm) and one perfusion graft (8mm). Three aortic arch branches were reconstructed independently using this branched graft by the selective cerebral perfusion method. There were three death in the emergency surgery (6 cases; 50% mortality) and no death in the elective surgery (8 cases; no mortality). There was no complication related to the branched sealed graft in this series. Branched sealed graft is useful to reconstruct the aortic arch and arch branches and may play an important role to decrease the bleeding and to reduce the operating time in aortic arch surgery.
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A. ISHIZAKI, K. KUKITA, Y. TAKAHASHI, N. YANAGIDA, M. OKANO, J. SUDOH, ...
1997 Volume 26 Issue 3 Pages
629-631
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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We carried out directional atherectomy (DA) using a Simpson catheter to the stenosis of six access grafts, for a total of 12 times. Although two grafts could not obtain an improvement of the obstruction by DA, four grafts could obtain the improvement. Sufficient release of graft stenosis was obtained after DA, and the increase of blood flow volume and a decrease of venous pressure were observed. Repeated DA was performed when recurrent stenosis was identified. A mean interval between DA and graft re-stenosis was 8 months. For the treatment of the grafts stenosis, directional atherectomy is a useful method and can be carried out easily and repeatedly.
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H. WAKIYAMA, K. ATAKA, K. INOUE, N. OZAKI, K. NAKAGIRI, T. AZAMI, N. Y ...
1997 Volume 26 Issue 3 Pages
632-636
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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Crosslinking of fibrin monomers by activated factor XIII is a final event in blood coagulation. We evaluated the serum level of XIIIa during cardopulmonary bypass (CPB) and their relationship with the extent of perioperative bleeding. And also coagulo-fibrinolytic molecular markers were analyzed Preoperative XIIIa levels ranged 62% to 123% (mean; 87%±20%) and the levels significantly fell down to 50%±13% at 10 minutes after the initiation of CPB and lower levels continued until the dscontinuation of CPB. Significant inverse coirelations were obsarved between preoperative leves of XIIIa and the extent of intraoperative bleeding, and there were the same associations between XIIIa levels during CPB andearly postoperative bleeding. In view of the above findings, low levels of factor XIIIa should be includedamong the list of risk factors for blood loss after cardiac surgery
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TA TAKAHASHI, K NAKAI, N SATO, S FUJIKAWA, K TADOKORO, T JYUJI, M MURA ...
1997 Volume 26 Issue 3 Pages
637-640
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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We have prepared rehydrated lyophilized (RL) human platelets as a candidate for platelet substitute. Platelets prepared from buffy-coats were fixed with 1.8% paraformaldehyde, frozen in the presence of 5% bovine serum albumin and stored after lyophilization. RL platelets preserved ristocetin-dependent aggregation but not collagen-induced aggregation. Flow cytometric analysis of membrane glycoproteins revealed the presence of GPIb and GPIIIa. This also showed appearance of GMP-140, which is a marker of platelet activation. Transmission electron micrographic analysis showed no morphological difference between fresh and RL platelets. These results suggest that RL platelets is a promissing candidate that can substitute the adhesion capacity of platelets.
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S. ENDO, T. KAWADA, M. HOZON, K. KIMURA, Y. OKADA, S. FUNAKI, N. YAMAT ...
1997 Volume 26 Issue 3 Pages
641-644
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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Anticoagulant effects and haematological benefits of the use of argatroban during cardiopulmonary bypass (CPB) were evaluated. CPB was performed using a membrane oxygenator (Exceran-prime, HPO-15-C, Senkoika Corp.), a centrifugal pump (HPO-15/HAP-21, Nikkiso, Co. Lts) and standard vinylchloride tubing, without a reservoir. Blood flow and revolutions of the centrifugal pump were kept constant during CPB. Nine dogs (16-20kg) were used. Those in group N (n=3) received no anticoagulant treatment, those in group H (n=3) were administered heparin (200IU/kg), and those in group A (n=3) received continuous intravenous infusion of argatroban (10μg/kg/min). CPB was carried out at a mean flow of 80ml/kg/min for 90 minuites. ACT was significantly prolonged in group H, but was maintained around 150 sec in group A. Platelet aggregation was significantly inhibited by argatroban and subsequent platelet loss was preveted. Free Hb and LDH were significantly lower in group A than in group H, suggesting that argatroban might prevent hemolysis. No macroscopic thrombus formation was observed in the hollow fibers of the oxygenator and other portions of the circuit in groups H and A. A argatroban was considered useful for preventing platelet loss and hemolysis during short-term CPB without a reservoir.
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S HIRAI, S FUKUNAGA, N MITSUI, M SUESHIRO, K OKADA, K TAHARA, M WATARI ...
1997 Volume 26 Issue 3 Pages
645-649
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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A blood chamber with a silicone lenticular sac and two silicone tri-leaflet valves made en bloc was manufactured using die caster for a ventricular assist device (VAD) that would be less expensive. Regurgitation of the silicone valve was measured 205ml/min, and that of Björk-Shiley monostrut valve was measured 321ml/min. Pressure gradient across the silicone valve was slightly greater than that across the monostrut valves. By this VAD, the maximam output flow of 6.3L/min was achieved at the rate of 80bpm in a Donovan type mock circulatory system, which was selected the preload of 12mmHg, the afterload of 120mmHg, the driving pressure of 160mmHg, the driving vacuum of 20mmHg and the percent systole 35%. The VAD worked well for 54 days in an overflow type mock circulatory system at the afterload of 100mmHg.
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N AKASAKA, K GOH, H YAMAMOTO, N AZUMA, H UCHIDA, S KAWAI, T KADOHAMA, ...
1997 Volume 26 Issue 3 Pages
650-652
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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Six patients underwent percutaneous cardiopulmonary support (PCPS) for severe cardiorespiratory dysfunction. There were 4 males and 2 females with the age ranging from 53 to 74 years old (mean 64). Two patients were in cardiogenic shock due to stuck mitral prosthesis and pulmonary embolism, 2 patients suffered from intractable ventricular fibrillation, 1 patient could not come off bypass after cardiac operation, and another patient was severely hypoxic due to pneumonia after pulmonary lobectomy. The duration of PCPS ranged from 1 to 72 hours (mean 26). Activated clotting time was kept between 180 and 250 seconds by continuous administration of heparin or naphamostat mesilate during PCPS. The inner surface of PCPS circuits, centrifugal pumps, and membrane oxygenators were entirely coated with heparin. Four patients came off PCPS and survived, and 2 died of multiple organ failure and irreversible respiratory failure. Major complications were massive hemolysis in 1 patient and ischemic lower extremities in 2 patients. No central nervous system damage nor hemorrhagic complications were observed. PCPS was effective in controlling preoperative cardiac failure and intractable ventricular arrhythmias.
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S. TANABET, T. SUGANO, Y. KATAYAMA, H. MATSUNAGA, Y. OHKOHCHI, T. TANA ...
1997 Volume 26 Issue 3 Pages
653-658
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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A seven-day assistance by v-v ECMO saved a 52-years-old male patient with postpneumonectomy pulmonary edema. He had undergone right pneumonectomy for his lung cancer. Postpneumonectomy lung edema occurred six hours after operation, and became serious to life-threatening on the second postoperative day. After that, v-v ECMO had been working for seven days with one unit of Carmeda® coating circuit, centrifugal pump and membrane oxygenator (Maxima®). Continuous heparin administration of 400 units/hour had kept ACT level about 200 sec. Under v-v ECMO with blood perfusion of 4.0L/min. and 2L/min. of oxygen flow, it was possible to lighten the condition of the respirator: F
iO
2; from 1.0 to 0.21 and PEEP; from 8cm H
2O to ZEEP. The patient had undergone 5 or 6 times of bronchial toilet everyday and airway pressure and pulmonary arterial pressure had been normalized in the following 7 days. The ECMO was weaned in the 8th postoperative day. During assistance with ECMO, only a little change was observed in platelet counts, d-d dimer, and TAT values; no bleeding nor thromboembolic episodes had been experienced. The goal of ECMO was estimated well by arterio-venous difference of oxygen contents, lung compliance, pulmonary arterial pressure, chest X-ray film and contents of the bronchial drainage. V-v ECMO rescued a patient with lung cancer from life-threatening postpneumonectomy pulmonary edema.
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Y. NARITA, H. OHTEKI, K. FURUKAWA, K. DOI
1997 Volume 26 Issue 3 Pages
659-663
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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Introduction: In general, Oxygenators that are used for Percutaneous Cardiopulmonary Support (PCPS) and Extracorporeal menhrane oxygenation (ECMO) are currently used also for open heart surgery. However, the selection of an appropriate oxygenator for POPS is not established. We have been used four type oxygenators so far, Mera/HPO-15H for 15 patients, huraray/Menox AL-4000 for 18 patients, AL-6000 for 18 patients, and Avecor/Ultrox-2 for 6 patients. Methods & Results: The time of cardiopulmonary bypass for each oxygenators were as follows: HPO-15H for mean 5 hours 20 min (29min. -20hours).; A1-4000 for mean 27 hours (82min. -144hours); AL-6000 for mean 31 hours (95min. -186hours); and Ultrox-2 for mean 42.5hours (5hours -117.5hours). Three cases of the oxygenator should be exchanged becouse of in appropriate removal of carhondioxide. Also, there were two cases of blood leakage from the crack of oxygenator, and the thrombus production at the blood outlet port of oxygenator were seen in many cases. Conclusion: Further development of oxygenator for such as POPS, ECMO and for longer use should be encouraged.
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T. SUGANO, S. TANABE, T. MAESHIRO, H. MATSUNAGA, Y. OHKOHCHI, T. TANAK ...
1997 Volume 26 Issue 3 Pages
664-667
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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We experienced two cases of endotracheal intervention under extracorporeal membrane oxygenation (ECMO). We could not manage these patients with conventional endotracheal anesthesia because of critical large airway obstruction. These procedures released the patients from dyspnea. Case 1 was a 65-years-old male. He had undergone left lower lobectomy for epidermoid cell carcinoma of lung before 6 months. The recurrent cancer occupied the carina and the right main bronchus; the obstruction occurred. We were successful in YAG laser therapy of this case under venovenous ECMO (v-v ECMO). Blood had been completely mixed before aorta, blood gas analysis from the peripheral artery represented average O
2 and CO
2 condition. Case 2 was a 65-years-old female. She had undergone extended radical hysterectomy for the right ovarian cancer before two years. The ovarian adenocarcinoma had spread to the mediastinal lymphnodes and lung; severe obstruction of the canna and the left main bronchus occurred. We inserted tracheobronchial stent under venoarterial ECMO (v-a ECMO). These two cases showed effectiveness and safety of ECMO; it secured gas exchange during long apnea for endotracheal approach. In case without cardiac disorder, v-v ECMO is easier to estimate its effectiveness in viva and simpler to set up and to remove than v-a ECMO.
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K. IMANISHI, K. IMACHI, Y. ABE, T. CHINZEI, H. YOSHITO, N. TSUTSUI, I. ...
1997 Volume 26 Issue 3 Pages
668-675
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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We have been developing a percutan eous type left ventricular assist device named Modified Assist Device (MAD). The system was composed of an air driven sac-type blood pump and can nula in which in flow an doutflow valves were in stalled. In the MAD Type-5, maximum pump flow of 2.5 1/min was obtained in the mock circulatiry study. For clinical application of this ventricular assist device, the newest model of MAD Type-6 was developed and was evaluated in iv vitro and in vivo experiments. To obtain the good anatomical fitting and durability, the spiral was installed in the can nula of MAD Type-6. In in vitro evaluation, the pressur a gradient of the in flow and outflow valve was 110cm H2O and 75cm H2O under the flow rate of 21/min. In the evaluation of hemolysis, the index of hemolysis was almost the same as that of centrifugal pump. The durability test was maintained for more than 30 days with out deterioration of this system. In the animal experiment using mongrel dogs, more effective systolic unloading and diastolic augmentation were observed by the activation of the MAD Type-6 compared with IABP assist. As for the peripheral circulation, increases in the carotid artery blood flow were observed by the assist by MAD Type-6 compared with the assist by IABP. In con elusion, the MAD Type-6 had the pulsatile flow and was thought to have the design and function for clinical application.
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M. NISHIDA, T. YAMANE
1997 Volume 26 Issue 3 Pages
676-680
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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Washout holes located in the impeller of a centrifugal blood pump have some advantages in preventing the thrombus formation in the gap behind the impeller where the blood is able to stagnate. In this study, flow rates through the washout holes were measured by flow visualization analysis, in order to gain the design index of the hole. Using the scale-up model pump, the flow vectors were obtained by 4-frame particle tracking velocimetry with the laser light sheet and high-speed video camera and the flow through the washout holes were calculated. The flow through the washout hole depends on the pump Reynolds number and specific speed. When the external flow resistance is constant, the flow through the washout hole is proportional to the pump external flow. When the impeller rotating speed is constant, the flow through the washout hole increases rapidly with the increase of the external flow resistance, and attains to the maximum, the twice the flow through the washout hole on the standard condition.
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Y. WAKISAKA, Y. TAENAKA, K. CHIKANARI, T. NAKATANI, E. TATSUMI, T. MAS ...
1997 Volume 26 Issue 3 Pages
681-686
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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Antithrombogenicity of a centrifugal pump (CP) developed in our institute is provided by a central balancing hole (BH) in an impeller. A current OP (N2) was ameliorated to obtain better antithrombogenicity, where the BH diameter was widened to improve self wash-out flow velocity, and an edge of the thrust bearing was rounded off to minimize flow separation. Effects of these modifications were assessed in long-term in vivo experiments. Antithrombogenicity, hemolytic property and effects on coagulability of the N2 was investigated in three goats. The N2 was installed paracorporeally between the left atrium and the aorta and continuously driven as long as possible. The N2 could run for 50, 200 and 381 days. The mean bypass flow rates were 6.8, 5.0 and 5.2 L/min, respectively. Fibrinogen were not increased until three weeks before the termination. GOT was kept a normal value until 8 days before the end. Creatinine, BUN, GPT, hemoglobin, plasma free hemoglobin and AT-3 were kept within normal ranges. Hemoglobin was kept about 70% of preoperative value. Plasma free hemoglobin was not incresed except in the last week of the second case. These results indicate that the N2 has excellent antithrombogenicity, acceptable hemolytic property and little damage to coagulability for prolonged use.
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T FUJIMOTO, Y MAKI, H WAKUI, K IZUMI, M UMEZU, K NAEMURA, T AKUTSU
1997 Volume 26 Issue 3 Pages
687-690
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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The dynamic behavior of prosthetic heart valves, which has an influence on blood flow adjacent to the valves is important from both clinical and hemodynamic viewpoints. In this experiment, the relationship between the mode of valve opening and flow pattern through the valve was analyzed. A Bjork-Shiley Monostrut valve (sewing ring diameter: 23mm) was incorporated in a mitral position of a mock circulatory system which contains a silastic left atrium and a rubber left ventricle driven by pneumatic pressure. Changes in valvular disc angle were measured at 500 frames per second using a high speed videocamera under two conditions in which the maximum flow rates were 15 and 20L/min. The video data indicated that the valve opening motion was greatly influenced by a flow rate pattern in the early opening period from 0 to 20msec. At this moment, a relationship between normal force as well as drug force applied to the disc is important to determine the initial movement of the disc.
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T. NAKATANI, Y. SASAKO, H. NONOGI, S. MIYAZAKI, K. KUMON, Y. KOSAKAI, ...
1997 Volume 26 Issue 3 Pages
691-698
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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In this paper, we presented our experience of as sisted circulation (percutaneous cardio-pulmonary support: PCPS, ventricular assist system: VAS) in critical care for acute profound heart failure including our compact integrated eardiopulmonary bypass unit (CIGU) and NCVC type VAS. We performed PCPS in 56 acute profound heart failures and VAS in 12 including acute deterioration of chronic profound heart failure from 1990. In PCPS cases, 7 weaned cases and 3 other cases, wha were switched to other procedures, were survived. In VAS cases, all three cased died without cardiac recovery under VAS management focused on cardiac recovery. In recent cases under VAS management focused on recovery of general condition, three acute profound heart failure cases and two acute deterioration cases showed heart recovery and two of them discharged (one case is on-going). In critical care for acute profound heart failure, acute worsening of hemodynamics and profound cardiac damage were serious problems. In acute worsening of hemodynamics, POPS is useful to maintain total circulation by quick application and our CICU is well matched to this purpose. In profoundly damaged heart cases, several cases may show cardiac recovery after prolonged VAS support. However, application of wearable LVAS or heart transplantation is needed in poor recGvery cases.
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Y TOMIZAWA, Y NOISHIKI, H NISHIDA, M ENDO, H. KOYANAGI
1997 Volume 26 Issue 3 Pages
699-703
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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Angiogenesis due to basic fibroblast growth factor (bFGF) in fabric prostheses is important for endothelialization. We activated endogenous cytokines by mincing and applied for in vivo tissue cultured technique. Canine adipose tissue was resected, minced into fragments, and suspended. This mixture was sieved through the wall of a fabric vascular prosthesis. Tissue-fragmented grafts (TF-grafts) were implanted into the abdominal aortae of 10 dogs, and 10 preclotted grafts were used as control subjects. Grafts were removed at 7 days after implantation. They were evaluated microscopically, immuohistologically. Endothelialization on thrombus was observed in the middle of the grafts. Cell proliferation around the fragments were active and those cells were bFGF positive. In the controls, the only perigraft tissue was bFGF positive. This suggests that activation of endogenous cytokines including bFGF is effective for non healing fabric vascular prostheses.
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K TAKEDA, M NAKAMOTO, S YASUNAGA, T GOYA, M YANASE, K YAMANAKA, K IZUM ...
1997 Volume 26 Issue 3 Pages
704-707
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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We monitored hematocrit continuously using CRIT-LINE in 35 patients. A significant correlation existed between hematocrit (Hct) obtained by automated blood cell counter and it measured by CRIT-LINE. There were three patterns in blood volume changes (ΔBV) obtained by CRIT-LINE, which could be classified as follows; The group A consisted of 26 patients, where time-coursed slope of ΔBV was down-ward. The slope (ΔBV/Hours) of the approximated straight line was constantly negative in ΔBV. The group B was composed of 5 patients and the time-coursed slope of ΔBV was upward. The slope was always positive. The group C included 4 patients, and its slope appeared to be positive to negative. It was considered that the patients in group B were overhydrated and those in group A or C could probably achieve their adequate body weights (BW) after HD. In 3 patients who underwent surgery under general anesthesia, we determined specific -ΔBV% levels in their preoperative periods. After surgery, HD could be conducted safely without measuring their BW before and after HD.
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Toshiyuki NAKAO, Tomonari OKADA
1997 Volume 26 Issue 3 Pages
708-712
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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Contributing Factors to Effecient Fluid Removal and Utility of Monitoring for Blood Volume Change in Hemodialysis Change of blood volume (ΔBV) and vascular refilling rate (VRR) during hemodialysis (HD) were investigated to improve efficiency and safety of fluid removal. 27% of 163 out-patients on maintenance HD required over 1.0L/h of UFR on the first dialysis day of the week. Only two in a group of 33 out-patients on maintenance HD showed peripheral edema before HD, whereas their abdominal girth significantly decreased after HD, which might mean removal of fluids from abdominal cavity. A maximum of -32% of ΔBV during HD, measured by CRIT-LINE™ instrument, was seen under O.7L/h of UFR, however in an overhydrated patient ΔBV was confined in only -3% even under 0.8L/h of UFR. Mean VRR at 0.5hours and 2 hours after beginning of HD, calculated from ΔBV when ultrafiltration were stopped, were 638ml/h and 905ml/h respectively. Fluid removal rates on single HD, expressed as % change of body weight, were significantly correlated with both VRR and abdominal girth reduction rates. In conclusion, the factor that makes high UFR in HD possible without any trouble is sufficient VRR being able to keep BV and, monitoring of ΔBV using CRIT-LINE™ instrument might be worth assessing the balance between UFR and VRR during HD.
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-STUDY OF ACETAMINOPHEN METABOLISM BY HYBRID ARTIFICIAL LIVER SYSTEM-
K. NAKAZAWA, H. MIZUMOTO, H. IJIMA, T. MATSUSHITA, K. FUNATSU
1997 Volume 26 Issue 3 Pages
713-718
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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Primary rat hepatocytes in monolayer and spheroid stationary culture converted acetaminophen to conjugated acetaminophen with glucuronide and sulfate. The metabolic activity of hepatocytes/spheroid stationary culture system was about 2 times higher than that of monolayer culture and was maintained for 10 days. We developed a device of liver model using a PUF/spheroid packed-bed module. The acetaminophen metabolic activity of hepatocyteslspheroid perfused culture system was about 2 times higher than that of stationary culture. Acetaminophen clearance and extraction ratio of hepatocyteslspheroid in the device were 0.013±0.001ml/min/module and 0.0093±0.0018/10
8 cells (g-liver), respectively. The value of extraction ratio was comparable with in vivo value, 0.016±0.005/10
8 cells reported by S. D. Studenberg using rat whole liver perfusion technique. Consequently, PUF/spheroid culture seems to provide a promising culture system as a drug metabolism simulator which will be used for drug screening
in vivo.
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-IMPROVEMENT OF THE MEDICAL TREATMENT EFFECT BY OPTIMIZATION OF THE SYSTEM-
H. IJIMA, S. WADA, K. NAKAZAWA, T. MATSUSHITA, K. FUNATSU
1997 Volume 26 Issue 3 Pages
719-723
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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We developed a hybrid artificial liver (Type 1, module volume: 5.65cm
3) utilizing PUF/hepatocyte spheroid culture. 80% of hepatic failure rats which induced by intraperitoneal injection of 0.5 g/kg-rat D-galactosamine could be recovered by extracorporeal circulation including this module. Then, optimization of the system was tried to aim at recovering a severed hepatic failure rat. A module volume was scaling up from 5.65cm
3 to 18.8cm
3 at 3.3 times (Type 2) and an extracorporeal blood circulation flow rate and a module side plasma circulation flow rate were changed from 0.5 to 1.0 ml/min and from 3.0 to 45.0 ml/min, respectively. In the results, blood ammonia of the hepatic failure rats which induced by 0.75 g/kg-rat D-galactosamine (PT=35.9 sec, normal value=20 sec) were well metabolized and four rats were recovered out of five by using a Type 2 module (recovery ratio is 80%). But the rat was died by using a Type 1 module. On the contrary, blood ammonia concentration was dramatically increased in the control experiments, and three rats were died out of four by using a Type 2 module (recovery ratio is 25%). From the above, it seems that the optimized artificial liver support system is effective for recovering the severer hepatic failure rats.
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IN ANHEPATIC RABBIT MODELS
T. YAMAMOTO, M. SSUZUKI, S. NAKA, K. TAKESHITA, H. ISHIBASHI, M. KODAM ...
1997 Volume 26 Issue 3 Pages
724-728
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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We prepared hollow fiber modules with 3.5×10
8 rabbit hepatocytes entrapped in collagen gel. This number approximately equal to 4% of the total number of hepatocytes in a 3kg rabbit. Extracorporeal hemoperfusion with two modules with hepatocytes directly connected was performed to evaluate the efficacy of 8% of the number of hepatocytes in anhepatic rabbit models. Serum ammonia levels were decreased and prolongation of PT was unproved by extracorporeal hemoperfusion. The increase in lactic acid and decrease in Fisher ratio and hepaplastin test were significantly inhibited at 5hr after initiation of extracorporeal hemoperfusion with 8% of the normal number of hepatocytes. PT and serum ammonia with 8% hepatocytes were better than those with 4% hepatocytes. These results show that the degree of efficacy depended on the number of hepatocytes included. On histological examination, no pathological changes were noted in kidney or lung and hepatocytes still appeared viable after extracorporeal hemoperfusion for 5hrs. In these results, extracorporeal hemoperfusion using 8% of the number of hepatocytes was safe, and effectively supported liver function in anhepatic models. This study provided evidence that our HAL system may in the future be clinically useful in supporting liver function by extracorporeal hemoperfusion.
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S SUZUKI, M MINESHIMA, Y SATO, S HIROTANI, I KANEKO, T SANAKA, T AGISH ...
1997 Volume 26 Issue 3 Pages
729-733
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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In order to improve solute removal efficiency in peritoneal dialysis, three types of recirculating peritoneal dialysis (RPD) were introduced: (a) simple RPD, (b) vibrating RPD and (c) flushing RPD. Recirculating-dialysis experiments using dogs were carried out under 100 ml/min of flow for both recirculating and delivered dialysates during an ex vivo study in comparison with (d) the conventional continuous ambulatory peritoneal dialysis (CAPD). The urea reduction rates in a 4 hr experiments of a canine study were 12.7±6.2% (mean±S.D.) for (a), 20.5±5.3% for (b), 20.8±5.5% for (c) and 3.3±3.9% for (d). All RPD had a significantly higher reduction rate than CAPD. Type (c) RPD is most acceptable for clinical application because of its higher solute removal efficiency and reasonable from economical aspects.
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T. OHNISHI, K. KOKUBO, K. SAKAI, M. FUKUDA, T. HIYOSHI
1997 Volume 26 Issue 3 Pages
734-738
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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Highly permeable dialysis membranes of asymmetrical structure were developed to mitigate amyloidosis which patients undergoing long-term dialysis treatment caught. Filtration and backfiltration through the membranes play an important part in solute transport. The rejections of the asymmetrical membranes are different between transport directions. To design high performance membranes, it is important to clarify the effects of the difference in rejection between directions of solute transport. Rejection and overall mass transfer coefficient of dextran were determined by filtration and counter-current dialysis experiments to compare transport characteristics of gradient structure membranes having a skin layer inside the wall of hollow fibers with those of the reverse gradient structure membranes having a skin layer outside. Overall mass transfer resistance and rejection of the gradient structure membranes are lower for transport from outside to inside than for that from inside to outside, indicating that solutes are easy to move from outside to inside. On the other hand, those of the reverse gradient structure membranes are lower for transport from inside to outside than for that from outside to inside, indicating that solutes are easy to move from inside to outside. The solute transport characteristics of the reverse gradient structure membranes are suitable for dialysis treatment. We conclude that thee overall mass transfer coefficient of the asymmetrical dialysis membrane increases by providing them with differences in rejection between transport directions.
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S. SHIMODA, K. NISHIDA, M. SAKAKIDA, Y. KONNO, K. ICHINOSE, T. UEMURA, ...
1997 Volume 26 Issue 3 Pages
739-743
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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For long-term clinical application of the wearable artificial endocrine pancreas, closed-loop subcutaneous insulin infusion algorithm has been developed by analyzing the kinetics of subcutaneous absorption of Insulin Lispro which was absorbed 2 to 3 times faster after subcutaneous injection than usual regular insulin. By applying this algorithm, blood glucose and plasma insulin responses to oral glucose load or dally glycemic excursions were similar to that with intravenous insulin infusion algorithm without showing any delayed hyperinsulinemia nor hypoglycemia. These data indicated feasibility of lone-term glycemic control in dabetic patients with closed-loop subcutaneous insulin infusion by the wearable artificial endocrine pancreas.
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Masami HOSHINO, Motohiro SAKAI, Hiroshi SAEGUSA, [in Japanese], Kazush ...
1997 Volume 26 Issue 3 Pages
744-748
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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In ten patients with acute pancreatitis, metabolic rate, organ failure (MOFscore), pancreatic enzyme, and glucose tolerance (administered insulin/glucose (energy) ratio: I/E ratio) were studied as well as triglyceride (TG) and free fatty acid (FFA). 1) Although glucose intolerance was severe (mean of I/E ratio was 78.1±41.5mIU/kcal), blood glucose (BG) was well controled (daily mean BG was 179.9±25.4mg/dl). This strict BG control was essential for the following results because serum TG and FFA are greatly influenced by BG. 2) There was negative relatioship between BEE and TG. 3) TG increased with the progress of MOF (mean of TG in patients with MOFscore between Oand 2, 3 and 5, and more than 6, was 105±30.1, 142.5±44.2, and 149.2±49.1 mg/dl, respectively). 4)Mean of TG in patients with serum amylase (AMY) more than 1000IU/L was significantly smaller than that in patients with AMY less than 1000IU/L. 5) FFA increased as I/E ratio increased. It seemed that hypermetabolism, organ failure and pancreatic enzyme influenced TG utilization by peripheral tissue, TG production by liver and TG resolution. There was close relationship between FFA and glucose intolerance. Artificial pancreas was useful not only for BG control, but also for the evaluation of fat metabolism.
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Y. TANIYAMA, T. MIYASAKA, Y. YOSHIMI, K. SAKAI
1997 Volume 26 Issue 3 Pages
749-751
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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A response current may be changed by fouling caused by protein or fibrobrast adsorption when a glucose sensor is implanted. By making the slope of glucose concentration in an enzyme layer flat, the influence of the fouling layer can be disregarded. In the present study, ferrocene binding with bovine serum albumin was used as a mediator of the glucose sensor. The proportionality between transient current after activation of glucose oxidase controlled by pulse potential and glucose concentration was examined. As a result, reaction right after the activation was not controlled by glucose diffusion, and transient current was dependent on glucose concentration. In conclusion, glucose concentration is determinable by measurement of transient current after the activation of glucose oxidase in the enzyme layer, and this method is applicable to long-term monitoring of glucose concentration.
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M. WAKI, C. NOJIRI, T. KIDO, T. SUGIYAMA, K. ISIHARA, N. NAKABAYASHI, ...
1997 Volume 26 Issue 3 Pages
752-755
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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We have evaluated four surface modification techniques for polymeric materials used in the blood contacting artificial organs. Proposed approaches to design nonthrombogenic polymer surfaces include 1) phase separated microdomain surfaces, 2) hydrophilic surfaces, 3) bioactive molecule incorporated surfaces, 4) biomembranelike surfaces. We have developed several in situ surface modification techniques according to these approaches to improve the blood compatibility of blood contacting surfaces of medical devices, including 1) HEMA-styrene block copolymer coating (HEMA/st), 2) poly ethylene glycol grafting (EG), 3) human thrombomodulin immobilization (hTM), 4) 2-methacryloyl oxyethyl phosphorylcholin (MPC) copolymer coating onto segmented polyurethane (PU) surfaces. These surface-modified PUs were evaluated using an epifluorescent video microscope combined with a parallel plate flow cell (EVM system) for assessing
in vitro platelet adhesion and complement activation. All surfaces showed significantly lower platelet adhesion than nontreated PU, and showed the ranking of the amount of adhered platelet as follows: PU>EG>hTM>MPCs>HEMA/st. As for complement activation, hTM showed the least C3a production, which attributed to its inherent inhibitory effects on complement activation. Ever known characteristics of each material were confirmed in this experiment. Thus, this EVM system has been proven to be an excellent
in vitro analytical method for relative evaluations of nonthrombogenicity of biomaterials.
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M. SHIRAO, S. SUZUKI, S. GOTOU, H. NAKAZAWA
1997 Volume 26 Issue 3 Pages
756-761
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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In this study, we investigated about active oxygen and morophological change of HL-60 cells adherated polymeric materials. Active oxygen produced by neutrophil-like HL-60 cells on polymeric materials was measured with chemiluminescence detector. The levels of active oxygen produced by cells on various polymer were different. However, there was no correlation between active oxygen and contact angle. Polystyrene was then sulfonated with concentrated sulfuric acid As the degree of sulfonation increased, the active oxygen produced by the cells decreased The cell adhesion rates on polystyrene sulfonated polystyrene were not different. The fine structures of neutrophil-like HL-60 cells adhering to modified polystyrene were observed by scanning electromicroscopy. The shape of cells on polystyrene was flat, whereas it was normal on sulfonated polystyrene. The fluorescence photobleaching recoveries on cell membrane were different between the two polymeric surfaces.
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Examination of hybridomas' proliferation potency and function
H. ITAGAKI, H. DOI, N. OHKO, S. SATOMI, S. SATOU, Y. TAGUCHI
1997 Volume 26 Issue 3 Pages
762-766
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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We developed a new cell fusion method which was sterile, noncontact, and selective technique under the microscope, using the micro-processing device by LASER. By this technique, we succeeded in fusing myeloma cell (SP2) and lymphocyte in mouse. We also defined the proliferation of the fused cells in HAT medium and the function of the fused cells in the Ouchterlony method, i. e. production of IgG. This method enable us to make hybrydomas from very smalln umber of cells and to fuse target cells selectively. This method is applicable to fuse cells which are difficult to be fused by conventional methods.
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I. KAETSU, K. UCHIDA, Y. SUZUKI, K. SUTANI
1997 Volume 26 Issue 3 Pages
767-771
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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In order to clarify the formation and function of the neural network, the electric activity of neurons was studied by simultaneous and multi-points measurements. Two kinds of MED were used and the cortical and hippocampal cell of rats were cultivated. Cortical cells were cultivated over 2 weeks on MED and the periodic action potentials were detected. Those potentials were retarded by the additions of 5mM Mg
2+ and 50μM APV. Most cells showed the synchronized action potentials and the cycle of potentials were shortened with the proceed of cultivation. It was deduced that synapse binding was increased and extended rapidly in the period from the 4th day to the 9th day of cultivation. It was deduced that the neural network was formed at the same time in accordance to the synchronization.
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R. MATSUI, K. ISHIKAWA, Y. TAKANO, T. KATAKURA
1997 Volume 26 Issue 3 Pages
772-778
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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Full-thickness skin flap of dimensions 5x5 cm with stem on the caudal side was raised from the skeletal muscle of the one side of the back of a guinea-pig. The flap was placed on the recipient bed and sutured to the margin after the subcutaneous fascias of the bottom excised from the flap. Defect wound of dimensions 2×2cm exposing skeletal muscle was prepared in the center of the flap at 7 days after flap operation. Then control defect wound free of flap were prepared on the other side of the back. Controls were closed at 21 days after preparation under dry environment of cotton gauze. Defect wounds in the flaps were retained initial wound areas at 28 days after preparation under cotton gauze, and clearly inhibited wound contraction, granulation and epithelialization. The defect wound in the flap was considered model delayed wound healing as deep skin ulcer and decubitus. The defect wounds in the flaps were treated with application of the collagen hydorogel material under polyurethane film dressing and with application of hydrocolloid dressing. Wounds applied collagen hydrogel material were closed at 28 days. However, wounds applied hydrocolloid dressing were expanded the areas and the depths.
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S. NAGANUMA, T. YAMBE, H. AKIHO, S. KOBAYASHI, K. SHIZUKA, S. NITTA, T ...
1997 Volume 26 Issue 3 Pages
779-784
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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In order to improve several disadvantage of a centrifugal pump, we have developed a new principle of rotary blood pumps. This Magnetic Rotary Pump (MRP) consists of a brushless DC motor system and a unique shaped pump housing. Basic pump housing is shaped a rounding cylinder, and a magnetized ball roller is set into this cylinder. The radius of a prototype MRP is 2.0cm, and the height is 1.2cm. Driving system, a disc on which permanent magnet is fasten is joined to brushless DC motor, is attached to the basal plain of pump housing. This roller is moved round in the cylinder by magnetically, and blood is continuously pushed out. By this prototype MRP, pump output is gained about 1.0 l/min against 30 mmHg afterload under rotational speed of 300 rpm. The advantages of the MRP are as follows; 1) Rotation shaft and impeller do not exist. 2) The structure of MRP is very simple. 3) Easy blood sealing is achieved by another centrifugal pump. 4) Hemolysis may be lower because of a shaftless and an impellerless configuration. 5) Optimization in size of MRP may be useful as the pump for human use.
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H. MIYAKE
1997 Volume 26 Issue 3 Pages
785-790
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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The Shape Memory Alloy (SMA) artificial muscle, which is idealized as a living skeletal muscle and applied to medical/welfare robot arm system, has been developed and used for a force presentation (FP) device for aged people. In order to build a better robot arm, following approaches were studied; 1) To improve the formerly developed artificial muscle and to assess its characteristics. 2) From the former robot arm's problems, to develop the master- and slave-arm to mount new artificial muscle, and to assess the mechanical characteristics. Following results were obtained; 1) The new artificial muscle was much improved. 2) The arm system also much improved. These experimental results lead to the conclusions that the improved SMA artificial muscle is able to build up the better artificial arm system.
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K. ISHIKAWA, R. MATSUI, Y. TAKANO, T. KATAKURA
1997 Volume 26 Issue 3 Pages
791-797
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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We tried to preparation of good biocompatible hydrogel, and studied to the biomedical applications. Collagen solution were incubated with Copper (II) ion (0.1mM) and ascorbate (0.1mM) in neutral buffer (pH7.4) at 37°C for 4hr, and made translucent and viscoelastic hydrogel. The hydrogel was capable of absorbing water of 20 to 200 times of its deadweight and had hemostatic effect. It was cleared that hydrogel showed a good tissue-compatibility and biodegradability after implatation in rats. Therefore it is concluded that the hydrogel can be used in biomedical applications such as drug delivery systems, hemostat, and wound dressings.
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-CURRENT STATUR AND FUTURE PROBLEMS-
Hiroshi NISHIDA, Tomohiro NISHINAKA, Hideyuki TOMIOKA, Akihiko TOYAMA, ...
1997 Volume 26 Issue 3 Pages
798-802
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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In chronic heart failure, development and establishment of the environment for pul satile assist device and heart transplantation are definitive waysto pursue in the future. However, in acute heart failure, the gap between percutaneous cardiopulmonary support (PCPS) and pulsatile assist device is very wide and those are not continuously incorporated in the strategy of the treatment. Despite of various efforts for longer and more physiologic support with PCPS such as heparin coating of whole circuit or improvement of durability of artificial membrane oxygenator, bypass type itself is a limiting factor in venoarterial bypass in terms of insufficient support for the left ventricle. To solve this obstacle, we need to develop reliable, safe, easy and practical percutaneous left ventricular sapport system such as Hemopump. For further development of assist circulation in Japan, cooperation between clinician and researcher is olso mandatory.
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Y ICHIKAWA, Y NOISHIKI, T SOMA, T KOSUGE, I YAMAZAKI, Y YANO, M TOBE, ...
1997 Volume 26 Issue 3 Pages
803-805
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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Neointima formation of fabric vasucular prosthesis is observed in general at only the areas near anastomotic sites in clinical cases in a long term periods.
Neointima cell lining with elastic laminae and smooth muscle cells of an adipose tissue fragmented vascular prosthesis was seen at 4 months after surgery at every part of the luminal surface in clinical case. And the removed specimen 10 months after implantation showed neointima formation composed of circular elastic laminae and smooth muscle cells.
These finding have never been reported for any other fabric vascular prostheses previously in clinical setting.
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K. KAWAHITO, R. BENKOWSKI, S. OTSUBO, K. FUSE, Y. NOSÉ, M. E. D ...
1997 Volume 26 Issue 3 Pages
806-810
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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We introduce the computer technology to enable an accurate, efficient, and reliable design process of an implantable axial flow VAD. The device design is computer-modeled with a parametric solid modeler. To eliminate the high negative pressure area, we performed computational fluid stress analysis on pump design. To improve efficiency and anti-thrombogenicity, CFD (computational fluid dynamics) study is performed to determine pressure and velocity of the fluid in the pump and eliminate the stagnant areas. Machining paths for prototype fabrication are generated using CAM software. And they are machined using CNC (computer numerically controlled) milling machine. Hemolytic characteristics was dramatically improved to 0.002g/100L of normalized index of hemolysis. Total system efficiency was improved to 14%. And Ex vivo 2 week implantation demonstrated excellent anti-thrombogenicity. The use of the CAD/CAM/CAE made it possible to develop a VAD rapidly and successfully.
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T. SUEDA, H. SHINJI, S. FUKUNAGA, Y. MATSUURA
1997 Volume 26 Issue 3 Pages
811-814
Published: June 15, 1997
Released on J-STAGE: October 07, 2011
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We have devised the following artififial lungs and evaluated the hardware of these devices. 1) An outside flow membrane oxygenator using a silicone hollow fiber was developed and is available for clinical use. This oxygenator is useful in selective cerebral perfusion. Modification such as heparin coating and minimization of the shape is desirable. 2) Liquid-liquid oxygenators using oxygenated perfluorocarbon (PFC) were devised. These oxygenator had an ability of oxygenation without membrane oxygenator but demerit of thromboembolism of PFC. 3) Intravascular balloon oxygenator (IVBO) was devised and evaluated experimentally. An animal experiment in which the IVBO was implanted into the inferior vena cava of a mongrel dog, showed an increase of venous return and oxygen pressure of the venous blood during pumping. Futher modification is hopeful in progress of the membrane material.
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