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[in Japanese]
1994 Volume 23 Issue 3 Pages
543
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
JOURNAL
FREE ACCESS
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T. YAMBE, S. NITTA, T. SONOBE, S. NAGANUMA, H. AKIHO, Y. KAKINUMA, S. ...
1994 Volume 23 Issue 3 Pages
545-550
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
JOURNAL
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In order to analyze the hemodynamics with artificial heart as an entity, not as the decomposed one, non-linear mathematical analyzing technique was utilized in chronic animal experiments using adult goats. For the comparison between the natural and artificial circulation, biventricular assist type total artificial circulation was adopted. After the implantation procedure, the goats were placed in the cage and hemodynamics with natural and artificial circulation were recorded under the awake conditions. Hemodynamic time series data were embedded into the four dimensional phase space and projected into the three dimensional phase space. During artificial circulation, reconstracted attractor showed lower dimensional chaotic behavior compared with natural circulation. Existence of deterministic chaos was suggested by the positive Lyapunov exponents. Our results suggest that circulation with artificial heart may be able to become the flexible and intelligent system by the achivement of the chaotic dynamics.
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M. YOSHIZAWA, H. TAKEDA, Y. YAMBE, S. NITTA, Y. ABE, T. ISOYAMA, K. IM ...
1994 Volume 23 Issue 3 Pages
551-558
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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One of the most difficult problems in developing air-driven implantable total artificial hearts (TAH's) is invisibility of the motion of the sac which prevents us from manually adjusting the drive pressure. The optimal operating control method developed by the authors for regulating the stroke volume of the ventricular assist device does not need visual monitoring of the motion of the sac, because this method can automatically control the drive pressure by means of the information on the systolic duration and the outflow rate of blood of the artificial heart. In order to make the air-driven TAH implantable, the optimal operating control method has been newly introduced into the TAH driver developed by University of Tokyo on the basis of Abe's 1/R control method requiring the stroke volume regulation. An animal experiment has been carried out to evaluate its function and discuss its problems for further improvement.
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D. ZHOU, H. FUJIMASU, A. NOGAWA, T. KIJIMA, M. UMEZU
1994 Volume 23 Issue 3 Pages
559-563
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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In order to obtain fundamentaldata on the effects of inner shapes of connectors on blood, in vitro hemolysis tests were performed by using an original designed extracorporeal circuit. Several types of stenotic connectors were made, and each piece was incorporated in each identical circuit. Then, heparinized fresh calf blood was infused into each circuit and was circulated by the centrifugal pump. In this comparative study, changes in plasma free hemoglobin in each circuit were obtained as a function of the pumping time of up to 6 hours. A brief summary of the results are as follows: 1) The connector could achieve a low hemolysis condition if there was an inlet taper of 20 degree, or a leading edge of only R=0.5mm. 2) A surface roughness (Ra) might be a great factor to the hemolysis, because hemolysis level on the Ra of 1.35μm produced by six times as compared with that on the Ra of 0.54μm. 3) Even if a connector had an abrupt stenosis with smooth surface (Ra=0.54μm), the hemolysis was kept low.
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N. KAWAGOISHI, C. NOJIRI, T. KIDO, K. SENSHU, T. KANAMORI, K. SAKAI
1994 Volume 23 Issue 3 Pages
564-570
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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Suitable evaluation systems are critical to design antithrombogenic biomaterials. We developed an
in vitro real-time observation test system to evaluate platelet/biomaterial interactions in whole blood under a defined flow condition. The system consists of a parallel plate flow chamber and epifluorescent video microscope (EVM). A glass coverslip coated with a polymer was incorporated into a flow chamber, and human whole blood containing platelets labeled with flourescent dye mepacrin was perfused at a wall shear rate of 200 sec
-1 for 20 min. In order to evaluate the feasibility of this system, two different segmented polyether-polyurethanes (SPEUs), PU-PTMG(650) and PU-PTMG(2000), were used. The results of surface characterizations by electron spectroscopy for chemical analysis (ESCA) and contact angle measurements were similar in both SPEUs. The percentage of the surface area of platelet coverage was measured at 1 min intervals. Plasma β-thromboglobulin (β-TG) and complement activation levels were also measured before and after each run. PU-PTMG(650) showed significantly higher adhered platelets than PU-PTMG(2000) at each time point. β-TG levels of PU-PTMG(650) were also higher than those of PU-PTMG(2000). Complement activation levels of PU-PTMG(650) were lower than those of PU-PTMG(2000). Thus, this EVM system has been proven to be an excellent and highly sensitive
in vitro analytical method for evaluation of platelet /biomaterial interactions.
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N YUI, T OKANO, Y SAKURAI, S KORA, T HIRANUMA, K ISHIKAWA, S YAMASHITA
1994 Volume 23 Issue 3 Pages
571-577
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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Changes in platelet function stored in mini-blood bags of crystalline-amorphous microstructured polymer (polyether-nylon multiblock-copolymer) were studied in terms of membrane fluidity and cytoplasmic free calcium levels ([Ca
2+]
i) of rabbit platelets. Fluorescent dye (Fura 2, DPH, or pyrene)-loaded platelet suspension was incubated at 37°C for 1h in the blood bags, and the metabolic changes of platelets during the incubation were evaluated by fluorescent spectroscopic technique. Surfaces of polymers used for commercially available blood bags enhanced the progress in platelet metabolism: dramatic decrease in membrane fluidity and an increases in [Ca
2+]
i. Further, the decrease in membrane fluidity was observed in prior to the increase in [Ca
2+]
i. In contrast, the surfaces of polyether-nylon multiblock-copolymers exhibited few changes in the platelet function. This result suggests that platelets in contact with the microstructured-surfaces can be inactivated in terms of the prevention of a decrease in membrane fluidity.
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T KANAMORI, K SAKAI, [in Japanese]
1994 Volume 23 Issue 3 Pages
578-584
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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Intramembrane diffusivity and water permeability are essential for characterization of dialysis membranes. The physical state of water present in the membrane may affect the solute diffusivity because solutes diffuse into only a fraction of water in the membrane and water inside the membrane changes places with that outside the membrane. Water content was measured in 31 dialysis membranes made of 7 polymers. The physical state of water was determined from data on water content by the conventional method and the differential scanning calorimetry and on partition coefficient measured by the use of tritium-labeled water. Three kinds of water state of varying molecular mobilities were found in the membranes and their volume ratio was dependent on the membrane material. The mechanism of solute transport through hydrophilic dialysis membranes of regenerated cellulose that strongly put restrictions on the movement of water in the membrane was different from that through hydrophobic dialysis membranes. Analysis of the intramembrane diffusivity of the regenerated cellulose membrane based on the free volume theory revealed that the solute diffusivity was dependent on water content.
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K. KANDA, T. OKA, T. MATSUDA
1994 Volume 23 Issue 3 Pages
585-589
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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An elastic tubular organism mainly composed of highly oriented collagen fibers was constructed to prepare ultrasmall diameter vascular grafts implantable in micro -or low pressure- circulation systems. Arterial smooth muscle cells (SMCs) derived from bovine aorta were 3-dimensionally embedded into tubularly shaped type I collagen gels (1mm in inner diameter, 7mm in outer diameter and 7cm in length). After incubation for 10 days, the transparent fragile gel became an opaque, dense and relatively rigid tubular organism of 0.5mm in inner diameter and 4cm in length. Subsequently, the dense organism was cross-linked with 1% glutaraldehyde in buffer for an hour and thoroughly washed with buffer. Freeze-drying and sterilization allowed the storage of an ultrasmall diameter vascular graft. This preparation method enabled us to tailorly make grafts with given sizes of inner and outer diameters as well as length, using different sizes of molds. The morphological investigation revealed that dense collagen fiber bundles were aligned in the circumferential direction in the grafts, which was induced by traction force of embedded SMCs. The freeze-dried graft (1mm in inner diameter), upon immersion into a saline for 3 min, became soft and elastic. Preliminary implantation into the abdominal aorta of a rat exhibited that implanted graft was pulsated with little bleeding under 3 hour-observation. The graft, composed of natural resources, is expected to induce rapid tissue regeneration.
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S. NITTA, T. YAMBE, T. SONOBE, S. NAGANUMA, Y. KAKINUMA, H. AKIHO, K. ...
1994 Volume 23 Issue 3 Pages
590-594
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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An electromagnetically driven univalved artificial heart (AN) has been developing to obtain a totally implantable Ventricular Assist Device (VAD) including drive system, using vibrating method in the frequency range of 3-50Hz. This newly designed VAD consists of a vibrating tube, coils, magnets and a jelly fish valve as the outlet valve. This VAD could generate more than 10l/min as an output volume, with 10Hz vibration using 20 volts supplied elective voltage. The flow patterns show vibrating flow according to drive frequencies. The fluid mechanical, hemodynamic and hematologic properties using a mock circulation and adult goats showed following advantages toward the achievement of a totally implantable VAD including a powering system. 1. Unidirectional flow through the univalved pump in the high frequency pump generation. 2. Simple drive mechanism. 3. A wide variety of output volume between 0.5l/-10l/min. 4. High efficiency transcutaneous electric power transmission.
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K. KANDA, T. OKA, T. MATSUDA
1994 Volume 23 Issue 3 Pages
595-601
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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We have developed the Valvo-Pump, an axial flow blood pump, which is implanted at the natural heart valve position. This device has several advantages; it fits well anatomically, its blood-contacting surface is small because the left or right ventricular cavity is used as the blood storage reservoir, and it is implanted as easily as an artificial heart valve replacement. The Valvo-pump consists of an impeller and a motor, both of which are encased in a housing. An impeller with 5 vanes (22.0mm in diameter) is connected to a samarium-cobalt-rare earth magnet direct current (DC) brushless motor (21.3mm in diameter and 24.9-mm-long). Sealing is achieved by means of a ferrofluidic seal. A pump flow of 16.1 l/min was obtained at a pump differential pressure of 7.7kPa (58mmHg), and a flow of 5.0 l/min at 18.4kPa (138mmHg) with a motor speed of 8500 revolutions per min (rpm). Sealing was kept perfect against a pressure of 29.3kPa (220mmHg) at 9000rpm. The Valvo-Pump is a very promising and simple method of circulatory support.
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CLINICAL EVALUATION OF THE OPTIMAL RANGE FOR WARFARIN THERAPY BY USING PT-INR
K. NAKANO, M. KITAMURA, G. OHTSUKA, A. HASHIMOTO, K. IWADE, M. AOSAKI, ...
1994 Volume 23 Issue 3 Pages
602-605
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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Although the optimal range of warfarin anticoagulation after mechanical valve replacement is world widely recommended from 4.5 to 3.0 in PT-INR, that is from 10 to 25% in thrombotest, which is eguivalent from 2.8 to 1.6 i n PT-INR, in our institute. We evaluated our warfarin anticoagulant therapy in 1554 patients with valve prostheses. The incidence of thromboembolic episodes were acceptably low and that of bleeding complication was much lower than those reported from Europe and North America. However, in about 10% of randomized selected patients in whom thrombotest was in the optimal range, the serum level of thrombin-anti-thrombin III complex and/or prothrombin fragment 1+2 were high. In conclusion, the 10-25% in thrombotest was adequate range in the majority of the patients but the 10% of the patients may require to change the therapeutic range of warfarin anticoagulation.
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Y MIYAMOTO, S NAKANO, H TAKANO, H. MATSUDA
1994 Volume 23 Issue 3 Pages
606-611
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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To achieve more physiologically successful cardiopulmonary bypass (CPB), the effects of a protease inhibitor, nafamostat mesilate (FUT), and heparincoated circuit were examined. 1. FUT: In Group F (n=15), 2mg/kg/hr of FUT was administered continuously during CPB. FUT was not given to Group C (n=15), who acted as controls. Platelet counts were maintained significantly higher in Group F. Although no difference was found in TAT, PIC was remarkably less in Group F than in Group C thoughout the study period. Postoperative blood loss was significantly less in Group F. The changes in serotonin, histamine and bradykinin in plasma were significantly suppressed by FUT. The perfusion pressure in Group F was maintained significantly higher than in Group C. 2.heparincoating: The biocompatibility of the Terumo covalent heparin coating method in a CPB circuit was evaluated in ex vivo experiment (n=6). Fresh human heparinized blood was primed in a miniature heparin-coated circuit and an identical noncoated circuit. TAT, platelet factor IV, granulocyte elastase and C3a were significantly lower in the heparincoated circuit. In addition, Carmeda Bioactive Circuit was used in the coronary bypass graft (n=15). Platelet counts and functions were maintained significantly higher in the coated group than in the control (n=15).
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K KAWAHITO, T INO, H ADACHI, H IDE, Y MIZUHARA, A YAMAGUCHI, S MURATA
1994 Volume 23 Issue 3 Pages
612-617
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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To control the blood coagulation on the blood contacting surface of the assist devices, heparin-coated equipment with low dose systemic heparinization was introduced in 34 patients. Percutaneous cardiopulmonary support(PCPS) was instituted in 25 patients, left heart bypass wass in 3 patients, and partial cardiopulmonary bypass during the operation of descending thoracic was in 6 patients. All blood contacting surfaces of the equipments were heparin-coated, activated coagulation time was maintained about 150 seconds in POPS, 150-200 seconds in left heart bypass, and 200 seconds in partial cardiopulmonary bypass during operation with or without systemically administered heparin. Eight patients (32%) are long-term survivors in PCPS, 0 (0%) in left heart bypass, and 4 (67%) in partial cardiopulmonary bypass during operation. From the results of clinical and postmorten examinations, there was no massive bleeding or no evidence of thromboembolism in the major organs. In some cases there was a little thrombi in the stagnant flow area in the oxygenator and connection of the tubing materials. In one case of PCPS which was maintained with low flow(0.8-1.0L/min.) during 41 hours, major clot was observed in the circuit. Although our experience indicated that the heparin-coated equipment with low dose systemic heparinization is beneficial for circulatory assist thus avoiding the risk of bleeding complications, it is need to improve the design to get rid of the stagnant flow area and to improve the durability of the equipment.
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J. MINAKUTI, A. SAITO, S. KAWASHIMA, K. SUGIURA, T. TAKAGI, T. MIYAZAK ...
1994 Volume 23 Issue 3 Pages
618-621
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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It is generally agreed that maintaining β 2MG concentration as low as possible is a fundamental method for the prevention of dialysis associated amyloidosis. The possibility exists that the continuous hemofiltration (CHF) might be effective for the achievement of lower β 2MG concentration. The effects upon coagulofibrinolytic system durling CHF were considered serious. CHF were performed on chronic hemodialysis patients. Filtration amount was either 5l/day or 10 l/day. Using heparine 500 to 750 units/ hour as anti-coagulant, the observations were made relating to durability of the filter and coagulofibrinolytic system for one to 8 weeks. The durability of the filter was 2 to 11 days and the filter was effective for a week on end, however, the durability of the filter decreased by degrees thereafter. Followingly, the decrease of platelet count and AT-III, and the raise of TAT and D-dimer were observed, and the activation of coagulofibrinolytic system was projected. It is considered that the practical applications of filters with superior anti-coagulation characteristics and the use of anti-platelet agent are indispensable for the clinical use in a long term.
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H NAKAJIMA, M KAIBARA, Y SUZUKI
1994 Volume 23 Issue 3 Pages
622-628
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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Substrate used were silica glass tube with the inner diameter between 1.3 to 1.5 mm. Endothelialization of the glass tube were performed by rotatory cultivation method using EC cells ( 1x 105 cells in 1 ml ) which were suspended in medium ( RPM1 1640 ) supplemented 10 % fetal bovine serum. Confluent and non-confluent glass tube vascular graft were made by this technique. The femoral artery and vein were replaced by cultured glass graft respectively. Graft were exposed to blood flow of Ca. 30ml/min for six hours. Confluent cultured glass grafts demonstrated 100 % patency in the femoral artery. SEM micro graphs showed a fairly clean surface morphology with minimal platelets adhesion. In contrast, confluent cultured grafts replaced in femoral vein showed un-uniform blood velocity distribution and considerable coverage of thrombus formation at the inferior side of the grafts which were affected significantly by the gravitation of the earth. Non-confluent cultured grafts replaced in the both femoral artery and vein demonstrated a large amount of thrombus formation in the early stage of the replacement. It would be concluded that grafts patency in vivo was influenced by flow dynamics of blood and confluence of the cell layer on the substrate.
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M KITAMURA, A TAKAZAWA, S AOMI, M HACHIDA, H NISHIDA, M ENDO, A HASHIM ...
1994 Volume 23 Issue 3 Pages
629-633
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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Strategy of circulatory support at the Heart Institute of Japan (HIJ) was assessed and compared with that at Stanford University Medical Center (SUMC). In the recent one year, 12 patients received circulatory support at HIJ and 6 patients underwent bridge to transplantation at SUMC. At HIJ, 3 of 6 non-cardiotomy patients with percutaneous cardiopulmonary support were weaned and one patient (16.7%) was survived. In 6 postcardiotomy patients with centrifugal pump and/or membrane oxygenator, 5 were weaned from circulatory support and 2 patients (33.3%) were discharged from the hospital. At SUMC, 5 of 6 bridge patients with Novacor left ventricular assist system or extracorporeal membrane oxygenation were transplanted and 4 patients (66.7%) were alive and discharged. Early and appropriate application of bridge to transplantation appeared to decrease hospital mortality of the patients with acute cardiac and pulmonary failure.
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K. NISHIMURA, M. YACOUB
1994 Volume 23 Issue 3 Pages
634-636
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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Early and late results of VAS were evaluated in conjunction with cardiac transplantation. The pumps employed were ABIOMED in 13 and Biomnedicus in 4 patients. All of 5 bridge patients improved hemodynamically after initiation of VAS, among which 2 patients were successfully transplanted. In 12 PTAF patients, 2 were weaned from VAS, and one survived. Other one patient underwent re-transplantation successfully. Complications were commonly observed such as bleeding, renal failure and infection. The results suggest that the use of VAS is effective, but it requires improvement of device itself to achieve better outcome.
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T. NAKATANI, H. TAKANO, H. ANAI, Y. TAENAKA, H. AKAGI, T. MASUZAWA, Y. ...
1994 Volume 23 Issue 3 Pages
637-640
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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We developed an implantable left ventricular assist system (LVAS) for bridge to transplant of small sized patients. The pump made of segmented polyether polyurethane was 50 mm in height, 86 mm in diameter, and 70 ml of nominal stroke volume. A drive line was connected with an external pneumatic control drive unit (CDU) percutaneously. Eleven adults goats were used for chronic animal experiments and pump was installed between the LV apex and the descending aorta and was placed in the abdominal wall. Six of them were sacrificed after 4 to 15 weeks while in good physical condition. There was no prominent thromboembolic symptoms without using any anti-thrombogenic agent. The new electrical impedance based monitoring and control system (Z system) was installed in the CDU for adequate control of implanted pumps. The pump performance was well monitored and the full-fill to full-empty drive was well controlled by this Z system. In conclusion, this LVAS should have a promising clinical use.
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S HAYASHI, A ORIHARA, I YOKOYAMA, H TAKAGI
1994 Volume 23 Issue 3 Pages
641-645
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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The endothelial cells of the cross-species transplanted organ are a target of the hyperacute rejection induced by the complement activation via classical and/or alternative pathway. To protect the cross-species endothellal cell from the attack of human complement, decay-accelerating factor and homologous restriction factor 20, which belong to human complement regulatory factors, were transfected into bovine aortic endothelial cells (BAEC) using retroviral vector, and the expression and function of DAF and HRF20 on BAEC were examined. This study demonstrated that BAEC transfected with DAF or HRF20 cDNA using retroviral vector have the satisfactory antigen expression of DAF or HRF20, which inhibit the species-specific complement dependent cell lysis.
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M MINESHIMA, M WATANUKI, K YAMAGATA, K ERA, S TERAOKA, T AGISHI, K OTA ...
1994 Volume 23 Issue 3 Pages
646-649
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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Development of continuous recirculating peritoneal dialysis(CRPD) as a new dialysis therapy. CRPD was newly introduced in order to improve solute removal efficiency in conventional dialysis therapies such as HD and CAPD. In CRPD, a part of the dialysate in the peritoneal cavity was circulated through a double-lumen catheter and purified by an out-side dialyzer. Safety and solute removal characteristics in CRPD were examined during a canine study. Peritoneal dialysance was obtained by a compartment model for CRPD. From this result, time-averaged concentration of BUN for an 8 hr/day CRPD combined with three exchanges/day CAPD is estimated to be 34.3mn/dl, which is much lower than 45.2mn/dl for a 12 hr/week HD. The optimum design of the out-side dialyzer for CRPD was examined during a study using an aqueous solution. A smaller type of hollow-fiber dialyzer having 87 μm for inner diameter and 112 mm for effective length can be determined as an optimal for CRPD.
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T. NAKAMURA, K. MIYAMOTO, K. TAKAMURA, M.n. TOKITA, M. KOMAI, T. KIM, ...
1994 Volume 23 Issue 3 Pages
650-653
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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We prepare amphiphilic clots binders consist of acylated gelatin to improve the functions of PET vascular graft by a novel synthetic method by which we obtained the acylated gelatin under mild reaction conditions. We find that the acylated gelatin is one of a thermoreversible gel forming materials. When the gel is cast on a PET film, it is found that the resultant gel tightly stuck on the PET surface that suggests the acyl groups strongly interact with the PET film by the hydrophobic interaction. Although the existence of the hydrophobic groups, the surface of the acylated gelatin gel is entirely hydrophilic. We also find that the melting temperatures of the acylated gelatin gels are rather higher than that of original gelatin gels that suggests the cross linking regions of the acylated gelatin gel may be stabilized by the hydrophobic interactions between acyl groups. These results indicate that the acylation of gelatin causes the preferable changes to the gelatin gel as a clots binding agent for PET vascular grafts.
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K. ISHIHARA, A. WATANABE, N. NAKABAYASHI
1994 Volume 23 Issue 3 Pages
654-659
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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To develop a hemocompatible cellulose hollow fiber membrane for hemodialysis, newly designed hemocompatible polymer of 2-methacryloyloxyethyl phosphorylcholine(MPC) was grafted on the cellulose hollow fibers. The graft copolymerization was carried out by a radical polymerization of MPC in aqueous solution in the presence of the cellulose membrane using cerium ions as an initiator. Both the tensile strength and the permeability of solute such as uric acid, vitamin-B12, lysozyme and albumin through the membrane were not influence by the grafting of the MPC. The complement activation induced by the cellulose membrane could be reduced by the grafting of the MPC on the surface. When the minimodule assembled with the modified cellulose hollow fibers was inserted between rabbit artery and vein to circulate blood in the absence of an anticoagulant for 45min, the clot formation could not be observed. The scanning electron microscopic observation confirmed that no blood cells adhered on the inner surface of the modified hollow fibers, however, serious clotting could observe on original cellulose hollow fibers. From these findings, the cellulose hollow fibers grafted with MPC polymer are concluded to be useful for hemodialysis, and can be applied to a non-heparinized hemodialysis technique.
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M. OHMAE, T. NAKAMURA, K. MIYAMOTO, M. TOKITA, T. KOMAI, M. YONEKAWA, ...
1994 Volume 23 Issue 3 Pages
660-664
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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Cryo precipitatable proteins constituting in cryogel existed in patient's plasma with autoimmune diseases such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Cryofiltration was developed by Nose et al that plasma separated from the whole blood by extracorporeal blood circulation system was cooled and then cryogel is removed by the second filter. Therapeutic efficiency on these autoimmune diseases was reported. On the other hand, we have found that main components of cryogel were fibrinogen (Fbg) and fibronectin (FN). FN has molecular diversity of plasma FN (pFN) and cellular (cFN), so we investigated FN involved in cryogel. The result showed that EDA(+)FN, usually in extracellular matrix, is existed in high percentage. In this study, we prepared heparinoid cellulose sulfate as the specific adsorbent for cryogel and then examined its adsorption ability by using human plasma at 30°C. The results was that about 90% of EDA(+)FN was removed while only 50% of total FN (pFN+cFN), 20% of Fbg and-13% of others were. Consequently this adsorbent seemed to be useful for the material of cryofiltration system.
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M TAKATSUKA, Y NAKAYAMA, T MATSUDA
1994 Volume 23 Issue 3 Pages
665-670
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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This paper describes a novel method providing durable layering of bioactive substance-immobilized hydrogels on fabricated devices. The preparation method is based on photochemistry of dithiocarbamate group which is dissociated into a highly reactive radical pair upon ultraviolet (UV) irradiation. By taking advantage of characteristics of the photo-generated radicals, hydrogel formation and its fixation onto a substrate surface were attained. The immobilization of urokinase and heparin onto poly(ethylene terephthalate) was demonstrated. First, a mixed aqueous solution containing of a photoreactive water-soluble poly(N, N-dimethylacrylamide-co-vinylbenzyl N, N-diethyl-dithio-carbamate) and bioactive substance was coated on the substrate. Subsequent UV irradiation resulted simultaneously in the formation of bioactive substance-immobilized hydrogel and its chemical fixation onto the substrate. Significant inhibition of platelet adhesion, markedly prolonged blood coagulation time, and dissolution of fibrin were observed, which are apparently derived from surface hydrogel, and released and surface- chemically fixed heparin and urokinase.
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T. KIYOTANI, M. TERAMACHI, Y. TAKIMOTO, N. OKUMURA, T. NAKAMURA, Y. SH ...
1994 Volume 23 Issue 3 Pages
671-674
Published: June 15, 1994
Released on J-STAGE: December 02, 2011
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We examined the effectiveness of gelatin glue (GRF® glue, E.H.S., France) for wound-healing in rats. On each rat, two or three 2-cm incisions were made with a scalpel in the back skin. Each wound was closed with GRF glue, fibrin glue or 3-0 nylon sutures. The tensile strength of each wound was measured and histological examination was conducted sequentially. Three days after surgery, the wounds treated with GRF glue had a higher tensile strength than those in the other two groups. From seven days of surgery, however, the tensile strength of wounds in the GRF group was not markedly greater than that of wounds in the other two groups. On histological examination, the GRFtreated wounds showed greater infiltration of inflammatory cells than the fibrin glue-treated wounds, but the GRF group showed no necrotic change in the surrounding tissue. At three weeks after surgery, the GRF glue remained in three out of six wounds, whereas the fibrin glue had disapeared by seven days in all wounds. We also examined the efficacy of GRF glue for sealing air leakage from lung tissue and for hematostasis of the liver and kidney in rabbits. GRF glue was effective for sealing air leakage from the lung tissue. It also had a hemostatic effect on oozing from parenchymal organs, but its hemostatic effect seemed insufficient for continuous arterial bleeding.
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H. SHIMIZU, T. UEDA, R. YOZU, I. KISO, K. NISHIKAWA, T. MAEHARA, M. OK ...
1994 Volume 23 Issue 3 Pages
675-678
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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Bachet and co-workers introduced GRF glue into the surgery of acute aortic dissection and reported excellent results. However this product had not been available until recently in Japan, at which time we had the opportunity to evaluate the usefulness of this material in cardiovascular surgery. From October 1992 to April 1993, GRF glue was applied to 20 patients, including seven patients with acute and five patients with chronic aortic dissection, two patients with thoracic and one patient with abdominal aortic aneurysm, four patients with aortic valvular disease, and one patient with ventricular septal perforation due to acute myocardial infarction. We lost five patients early postoperatively mainly due to the poor preoperative condition of these patients. Especially in patients with acute aortic dissection, the GRF glue proved to be very useful as an adhesive. The adhered sites were firmly reinforced and exhibited appropriate elasticity to suture. In other cases, the GRF glue was mainly used as a hemostatic agent, that is, it was applied over the incised tissue. It was efficient even in the application to the left ventricle when ventricular septal perforation occurred due to acute AMI or the severely calcificated aorta of Takayasu aortitis, both of which have been said to be difficult to suture and to arrest the bleeding. As the GRF glue was ineffective only in one case in whom it was applied to the active bleeding coronary sinus site, we believe that it should be used after drying the application site as much as possible. No side effects arose in any case. We conclude that GRF glue is safe and easy to use and is a very useful material for application to cardiovascular operation.
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Sunao KUBOTA
1994 Volume 23 Issue 3 Pages
679-684
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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Taking advantage of the conversion from water-insoluble to water- soluble states depending on the lower critical temperature (LOST) in thermoresponsive polymer ( PNIPAAm), the author has developed new type gauze coated with PNIPAAm that allows us easily to be removed from a wound simply by pouring cold solution onto this gauze. In this study, the new type gauze was placed onto a 4×4cm of full-thickness skin wound in the rat for 4, 7, and 14 days, respectively. When cold normal saline of 4°C which is below LOST was poured onto this gauze before removal, PNIPAAm was solubilized and therefore the gauze was easily removed without incurring any tissue damage even at 14 days after covering.
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T. ITAOKA, J. KEI, M. MURASUGI, K. CHINO, H. KANEYASU, K. OYAMA, K. ON ...
1994 Volume 23 Issue 3 Pages
685-689
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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The antithrombogenecity of the intravenous needle catheter made from segmented polymers based on poly(propyleneoxide) and nylon segment was clinically studied by an electron-microscope. We were able to observe electron-microscopically the copolymer having a crystalline thickness of 6.5nm and a maximum circumference of approximately 12nm and exposed crystalline width of 10 nm. From our electron-microscopic observations, it was seen that the absorption of protein on the catheter surface was smooth, and thus prevented thrombogenetic formation often associated. Furthermore, we were able to classify these thrombogenetic formations into 9 grades. This study suggests that the antithrombogenetic characteristics of the microdomainstructured polymer may be more beneficial for clinical use than conventional types.
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K. MIYAMOTO, T. NAKAMURA, M. TOKITA, T. KOMAI, M. YONEKAWA, A. KAWAMUR ...
1994 Volume 23 Issue 3 Pages
690-694
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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Based on the concept that the granulocyocyte ratio (G/L) in cancer patients suggested the increase of G/L closely related to the tumor growth and the decrease to the depletion, we have been investigating the extracorpoeal granulocyte adsorption system, depleting granulocyte mechanically, for the treatment of tumor bearing hosts. In order to clarify the therapeutic efficiency of this system, we have investigated the proteins adsorbed on the surfaces of granulocyte adsorption resin which was clinically applied. Extracted proteins obtained from the resin was analyzed with gel electrophresis (SDS-Page) and ion exchange chromatography. These analyzed results revealed that the characteristic protein was only extracted with saline containing heparin, molecular weight of the protein was estimated over 300kD. In Chromatogram, the peak of extracted proteins existed at the same position as that of Cellular Fibronectin-Heparin complex (cFN-Hep).
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H. TAIRA, A. TANAKA, K. KATAOKA, T. TSURUTA, M. HAYASHI
1994 Volume 23 Issue 3 Pages
695-699
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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We have synthesized Polystyrene derivatives having different content of polyamine side chain with repeating array of diamine (SA), and have evaluated adhesion, spreading and growth behavior of bovine aortic endothelial cells (BAEC) on their surfaces. Adhesion-%, Spreading-% and growth behavior of BAEC were increased with increasing diamine content in copolymer. To evaluate the effect of adsorbed serum protein on adhesion and spreading of BAEC, cell culture was carried out on the surfaces adsorbed with fetal calf serum (FCS) or bovine serum albumin (BSA) Adhesion and spreading of BAEC was increased with increasing diamine content in the copolymer on FCS adsorbed surface, whereas, on BSA adsorbed surface, BAEC adhesion was considerably prevented and no spreading cells were observed. Then, adsorption of bovine plasma vbronectin (FN) and bovine plasma vitronectin (VN) from FCS on SA surface was evaluated by enzyme immunoassay. It was found that the amount of adsorbed FN and VN was increased with increasing diamine content in the copolymer, suggesting a crucial role of these cell-adhesive proteins in BAEC growth on SA copolymer surfaces.
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Y SUZUKI, M KUSAKABE, M KAIBARA, M IWAKI, H SASABE, T. NISHISAKA
1994 Volume 23 Issue 3 Pages
700-707
Published: June 15, 1994
Released on J-STAGE: December 02, 2011
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Cell adhesion control on polymer surface by ion implantation has been studied. The specimens used were polystyrene (PS), Collagen coated PS (PS-C), Gelatin coated PS (PS-G) and oxygen plasma treated PS (PS-O). Adhesion of HeLa cell was improved on ion implanted PS. The cells could not adhere onto the ion implanted PS-C, PS-G and PS-O. Cell adhesion surface was enhanced by new functional groups introduced by ion implantation. The inhibition of cell adhesion was caused by the removal of protein and >C=O.
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T. TANI, K. RIN, K. TERAMOTO, Y. ENDO, M. KODAMA
1994 Volume 23 Issue 3 Pages
708-711
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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Anti bacterial and anti-fungal activities have been studied using the chloride or iodine compounds of polystyrene derivatives. E. coli (ATCC 25922), Saccharomyces cerevisiae and Candida albicans were incubated and prepared for 5ml PBS solution containing 10
4 or 10
5 of each bacteria. Those microbial solutions were incubated with 0.25g of anti-microbial materials. Poly(acetoamidomethylstyrene iodine;No.6-I) showed the strongest activities against bacteria and fungus. Anti-microbial activities by No.6-I were influenced with incubation temperature and thickness of polymer sheet. Lavage with distilled water extreamely decreased the activities of No.6-I after autoclave treatment. But supernatant or lavage solution never demonstrated antimicrobial activities.
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K KAWAHITO, T INO, H ADACHI, H IDE, A MIZUHARA, A YAMAGUCHI, S. MURATA
1994 Volume 23 Issue 3 Pages
712-716
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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FASUS copolymer is a newly synthesized antithrombotic material, the theoretical basis of which is attributed to its hydrophilic and hydrophobic microdomain structure. In this series of experiments, the blood compatibility of this polymer was evaluated by utilizing the methods of arterio-venous(A-V) shunt in rabbits. Small diameter polyvinyl chloride tubes(3.0mm I. D. and 60cm length) coated by FASUS on their internal surfaces(FASUS, n=5), and without coating(CONTROL, n=5) were implanted in rabbits as A-V shunts. Their differences were assessed by measuring for circulating platelet counts, platelet aggregability, APTT and PT. As a results, FASUS effectively suppressed the decrease in platelets counts and improved pro-longed APTT, there was no difference in PT and platelet aggregabiiity. In conclusion, FASUS showed promising blood compatibility by suppressing the activation of platelets and intrinsic factors.
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Y. NAKAYAMA, T. MATSUDA
1994 Volume 23 Issue 3 Pages
717-720
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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S. TANAKA, K. ISHIHARA, N. NAKABAYASHI
1994 Volume 23 Issue 3 Pages
721-725
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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The direct haemoperfusion (DHP) using activated charcoal(AC) beads as adsorbent is one of the important methods to remove toxins from circulating blood of acute intoxicated patients, however, because of its poor haemocompatibility of the coating materials, there still required careful and systemic anticoagulation during the extracorporeal circulation. In this study, to improve haemocompatibility of the AC beads surface, a new polymer having phospholipid polar group was synthesized and its availability as a coating material was evaluated through
in vitro and
in vivo experiments concerning polymer elution, adsorbing capacity of solute, and haemocompatibility. From the results obtained, it was confirmed that the copolymer(MBG) consisted of the three co-monomers, i.e. 2-methacryloyloxyethyl phosphorylcholine(MPC), n-butyl methacrylate(BMA) and glycidyl metha-crylate(GMA), could be firmly fixed on the surface of the poly (2-hydroxyethyl methacrylate)(PHEMA) coated AC beads through cross-linking treatment, and possessed high adsorbing capacity of solute (creatinine) even in the solution with plasma proteins and improved haemocompatibility as compared with that of the original PHEMA coated AC beads. These results suggest that, using the MBG-coated AC beads, dosage of the anticoagulant during DHP could possibly be reduced.
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Y. NAKAYAMA, T. MATSUDA
1994 Volume 23 Issue 3 Pages
726-730
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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(1) The direct etching of polymers using a KrF excimer laser with high fluence (1J/cm
2;above a threshold fluence), and (2) the surface modification of vinyl polymers using an ArF excimer laser with low fluence (30mJ/cm
2;below a threshold fluence), have been investigated. The results showed: (1) the etch depth per pulse of a KrF laser was a linear function to the number of pulses. Higher the glass transition temperature (
Tg) of polymern was smaller the etching depth. The polymers with high
Tg, such as polyimide and polycarbonate, exhibited an excellent structuring quality of the etching. (2) Exposure with an ArF laser to vinyl polymers, poly(vinyl alcohol) and poly(
p-amino styrene), resulted in simultaneous cleavage of the pendant functional groups and photooxidation, resulting in changing the surface wettability. These were confirmed by x-ray photoelectron spectra and water contact angle measurements. Little change in the surface composition was observed by exposure with a KrF laser. The chemical and physicochemical nature of the surfaces were altered, which depends on wavelength and dose of excimer laser.
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—EXPERIMENTAL STUDY—
O KAMISAWA, Y MISAWA, T HASEGAWA, K. FUSE
1994 Volume 23 Issue 3 Pages
731-734
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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Polyurethane sheet (Thoratec Laboratories Corporation, USA) is compliant material. It is composed of three layer and has high tensile strength and absolute tightness for air and fluids. In eight mongrel dogs chest wall defect (6×6 cm) was created by resecting 2 or 3 ribs. Then chest wall was reconstructed with the sheet. After implantation, paradoxical movement of the chest wall was not observed. One to nine months after implant, these sheets were harvested. Adhesion of the sheets to the lung was slight to moderate. On light microscopic examination, smooth fibrous tissue with collagen, mild foreign-body reaction and mild scar formation were observed. On scanning electron micrograph, mesothelial cells were not detected. In conclusion polyurethane sheet is cosidered to be applicable to chest wall reconstruction.
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T. SUGIYAMA, S. MIZUSHINA, T. SUGIURA, M. KIMURA, T. KIMURA, Y. HARADA
1994 Volume 23 Issue 3 Pages
735-739
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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Polyvinyl alcohol (PVA) Hydrogel, which includes a high proportion of water and has a high flexibility, has similar dynamic properties with the hypodermis-subcutaneous tissue. Chitin has a vulnerary facilitatory effect. Considering the characteristics of these two material, we proposed an implantable material consisting of PVA and chitin. As a test model of bio-compatibility we suggested a plate form with small holes of different diameters. A degree of invasions of tissues into these holes was used as a measure of bio-compatibility. Plates were implanted in five mongrel dogs. Silicone and polyurethane materials were treated into the same plate type form and implanted in the same mongrel dogs for comparison. As a result, it was ascertained that the increase of foreign body giant cells and inflammatory cells were inhibited and a growth of surrounding tissues was accelerated by the effect of chitin in comparison with those in silicone and polyurethane plates. The proposed material was promising as an implantable medical material. The present test method was also found to be effective for quantitative analysis of bio-compatibility.
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K. ABE, K. SUZUKI, T. OKANO, Y. SAKURAI, T. HONE
1994 Volume 23 Issue 3 Pages
740-747
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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In order to evaluate the suppressing ability of platelet microtubule(MT) deassembly on HEMA-St block copolymer surfaces having good antithrombogenicity in vivo, in vitro, colchicine-treated platelets that made contact with the polymer surfaces, that adhered for 3 hours on the polymer surfaces were analyzed by scanning and transmission electron microscopy. And then, the uneven degree of platelets after contact with the polymer surfaces was quantified by image analyzer. PSt and HEMA-St random copolymer surfaces were prepared as polymers for comparison. The interaction between the platelets and the polymer surfaces was carried out with the microsphere column method. Results of this investigation and a previous study used intact platelets have suggested that the block copolymer surfaces may not only inhibit the platelet MT deassembly but may also inhibit the platelet actin polymerization and actomyosin constriction compared to those of PSt and the random copolymer surfaces.
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M MO, Y NOISHIKI, M NAKAMURA, K YAMAMOTO, T KOSUGE, Y ICHIKAWA, K IMOT ...
1994 Volume 23 Issue 3 Pages
748-751
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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Biocompatibility of glutaraldehyde-treated (G), epoxy-treated (E), and non-treated(N) porcine aortic fragments were evaluated by adhesion and growth of cultured calf pulmonary artery endothelial cell(CPAE) and fibrob last (3T3 Swiss) on these prostheses. Porcine aortic fragments were treated with 0.625% glutaraldehyde solution for 9 hours for G, and 4% epoxy conpound (Denacol) solution for 4 hours for E. CPAE and 3T3 Swiss in culture medium were seeded on the fragments which were fixed on the bottom of culture dishes using 3% collagen gel. The aortic fragments were observed by light microscope after staining with hemato xylin on the day 2, 7, and 14. Number of adhered cells on the fragments was N>E≥G in CPAE experiments, and E>N≥G in 3T3 Swiss experiments on the day 14. These cross-linking treatments reduced biocompatibility for CPAE remarkably how ever not for 3T3 Swiss. Epoxy-treated fragments showed better biocompatibility than glutaraldehyde-treated fragments, although not biocompatible enough for endothelial seeding. These results demonstrated that tissue compatibilities of vasucular bioproshthesis were dependent on cross-linking agents and cell species.
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Shinichi SATOH, Satoshi NIU, Keiichi KANDA, Jirou HIRAI, Yukio WADA, T ...
1994 Volume 23 Issue 3 Pages
752-756
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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An aortic prosthesis which can be dilated by a percutaneus transluminal angioplasty(PTA) was developed. The caliber of this prosthesis was dilated to 1.5 times ex vivo and in vivo by PTA procedure. This prosthesis is made of woven polyester fiber fabric. The design is as follows;the transvers yarns of this graft consist of two types of fibers;one is weak and located the center of the transvers yarnsm, the other strong and spiraled around the former. A cutting-out of weak ones by a PTA resulted in the enlargement of the graft and the new large caliber was produced. The in vivo experiment proved safe to use a PTA for this graft in the high pressure system. This graft would reduce times of reoperations of child who was implanted the prosthesis of the aorta.
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H. KITO, N. NAKAJIMA, T. MATSUDA
1994 Volume 23 Issue 3 Pages
757-762
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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To credit a successful healing of vascular grafts, different cellular responses between luminal and outer graft surfaces are essentially required;antithrombogenicity for a luminal surface and enhanced tissue ingrowth for an outer surface. Differentiated design of luminal and outer graft surfaces may provide biocompatibility into small caliber grafts. Along with this concept, we designed photocurable extracellular matrices (ECMs) for graft surface coating materials. ECMss developed were photocurable chondroitm sulfate (CS) for a luminal surface and gelatin for an outer surface, both of which were partially derivatized with photodimerizab a groups such as cinnamate and coumarine groups and converted to produce water-insoluble gels upon ultraviolet irradiation. In vitro study showed that platelet adhesion on photogelled CS films was significantly reduced and endothelial cells adhered well on photogelled gelatin films. These materials were individually coated onto corresponding surfaces of knitted Dacron grafts (ID;5mm, length;5cm). At acute phase implantation up to one week into dogs, little cell adhesion was observed on luminal surfaces where photogelled CS uniformly covered and enhanced tissue ingrowth at an outer surface. Molecularly designed ECMs and their in vitro and acute in vivo performances appeared to work along with our concept.
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Y. EZAKI, M. TAKAHASI, Y. KOBARAI, A. TUKAMOTO, H. NAGAI, Y. TAKANO, T ...
1994 Volume 23 Issue 3 Pages
763-769
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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We have developed a new vascular graft (PF-V), which was made of high porous graft impregnated with plasmin-treated fibrin. The graft has enough compliant property by knitting elastic polyester fiber (porosity 2700ml/cm
2/min). Eleven PF-V grafts (4 to 5mmI. D. and 5.5 to 45cm in length) and ten control grafts (Sauvage EXS, 5mmI. D. and 5 to 8cm in length) were implanted in carotid or femoral arteries of 13 dogs without any anticoagulant such as heparin. The grafts were removed from one to nine months after surgery in comparison of handling, patency rate and histocompatibility. PF-V requiring no preclotting Prior to implantation and no bleeding was observed in all cases. The cumulative patency rate was 100% in PF-V after gmonths. In addition, We recognized good healing of PF-V. From these results, it is concluded that the new graft (PF-V) may be applied for peripheral arterial reconstruction.
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M. INABA, T. SASAJIMA, Y. IZUMI, N. OTANI, H. YOSHIDA, N. AZUMA, K. GO ...
1994 Volume 23 Issue 3 Pages
770-775
Published: June 15, 1994
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CORVITA
R vascular graft. We studied the healing characteristics and the patency of CORVITA
R vascular graft in experimental and clinical study. Fifteen grafts were implanted in abdominal aorta of mongrel dogs. Two dogs were sacrificed at 7 days and 10 of 13 dogs were followed from 3 to 32 months. At 3 and 6 months after implantation, the endothelial cell coverage was localized within several milimeters from anastomotic sites in electron microscopy and fibrin clots and thrombus were seen focally on the surface of the same grafts. After 20 months, the endothelial cell coverage was seen on the almost all surface of the graft. In histological examination, the intimal thickness of the graftwas about 200μm and mild anastomotic intimal hyperplasia wa sseen at 20 and 25 months. Dilatation or aneurysmal formationof the graft was not found in this study. From December 1992 to September 1993, 9 patients underwent femoro-popliteal bypass procedures (FPAK8, FPBK1) with CORVITA
R vascular grafts. All patients were male and the average age was 69.5 years. Claudication was indicated for all patients. They were followed from 1 to 10 months. Two grafts(18%) were thrombosed at 3 weeks and 10 months after operation and there were 1 operative death.
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Y OKUDA, M KOMETANI, M HAMAGUCHI, [in Japanese], S YAMANOUCHI, T KUMAD ...
1994 Volume 23 Issue 3 Pages
776-780
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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Gelatinized atelocollagen(GAC) or fibronectin(FN) were covalently immobilized onto the expanded polytetrafluoroethylene grafts(2mm internal diameter and 30μm fibril length). Micro-fibrils of the protein-immobilized grafts were complelely covered with the proteins and porous structure of the EPTFE was entirely maintained. These grafts were implanted into the rabbits' carotid arteries. After 60 minutes, the luminal surfaces of the GAC-immobilized grafts were completely covered with the smooth thrombus layer on which no platelets or erythrocytes were deposited. The protein-immobilization did not affect the patency rate up to 12 weeks. Endothelial cells(EC)-like cells coverage of the immobilized grafts was two times as much as that of the untreated ones. The smooth thrombus layer formed on the protein-immobilized grafts seems to be significant for healing and higher rate of EC-like cells coverage.
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M. KOMETANI, Y. OKUDA, K. KATAMI, S. YAMANOUCHI
1994 Volume 23 Issue 3 Pages
781-785
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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Endothelialization of artificial grafts may be enhanced by pretreatment with bio-matrices but its mechanisms have not been understood. In this study, we tried morphological analysis of endothelial like cells on expanded polytetrafluoroethylen (EPTFE) grafts (n=4) and fibronectin pretreated EPTFE (FN/EPTFE) grafts (n=3) implanted to the carotid artries of New Zealand white rabbits. Geometrical parameters of the cells {Area(A), Peripheral-length(P), max. -length, max. -width, Shape Index(4πA/P
2) and Cell Angle} were measured on scanning electronic micrograph of the cells with silver staine 4 weeks after implantation. This morphometry showed that values of Shape Index at an astomotic sites were significatly higher (p<0.001) than that on carotid arteries and values of the cell areas on EPTFE(n=2255) and FN/EPTFE (n=1743) were 2.6-fold and 2.0-fold bigger than that of endothelial cells on host arteries(n=387) and the cells spread bigger at migrating sites compaired with that at anastomotic sites. These results suggest that shape and size of endothelial like cells on artificial grafts were determined by some factors in ad-dition to shear stress and adherence with or without fibronectin pretreatment.
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Shirosaku KOIDE, Shunichi INAMURA, Kazuo KANABUCHI, Shigetoh ODAGIRI, ...
1994 Volume 23 Issue 3 Pages
786-790
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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We have had routinely performed femoro-popliteal(distal)arterial bypass with the ringed EPTFE grafts, 6mm in diameter, or reversed autologous saphenous veingrafts(ASVG), for superficial femoral arterio-sclerosis obliterans during the last 15 years period. The cumulative life- table patency The cumulative patency rate of EPTFE grafts resulted in 93(ASVG: 93) % at the first yer, 83(93) % at the third year, 71(87) % at the fifth year, 64(87) % at the seventh year and 55(87) % at the ninth year. The ringed EPTFE graft proved to be inferior to ASVG in the long-time.
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—COMPARISON OF EXTERNALLY SUPPORTED KNITTED DACRON AND AUTOLOGOUS SAPHFENOUS VEIN GRAFT—
S. OHBA, K. KOSUGA, K. URAGUCHI, K. YAMANA, K. OHISHI
1994 Volume 23 Issue 3 Pages
791-794
Published: June 15, 1994
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Between 1986 and 1992 we performed above-knee femoropopliteal bypass (AK-FPB) in twenty eight patients, or thirty seven limbs using externally supported knitted Dacron (EXS) and autologous saphenous vein (ASV). The background factors of both groups were not different. As adjuvant medication we used warfarin (100%, 33%), and/or antiplatelet drug (89%, 90%). In EXS group, seven patients, or nine limbs, the cumulative patency rates(each year number of graft) were 88.9%(8) at one year, 88.9%(8) at two years, 88.9%(4) at three years, 88.9%(2) at four years. On the other hand, the patency rates were 89.1%(26) at one year, 853%(25) at two years, 85.3%(23) at three years, 80.8%(19) at four years in ASV group, twenty one patients, or twenty eight limbs. EXS as the material of AK-FPB was not significantly different from ASV in patency rate, and was revealed useful.
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K. KANDA, H. MIWA, T. OKA, T. MATSUDA
1994 Volume 23 Issue 3 Pages
795-798
Published: June 15, 1994
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Hybrid vascular prostheses of 4mm in inner diameter were prepared by hierarchically incorporating endothelial cells and smooth muscle cells (SMCs) derived from mongrel dogs. The prepared grafts, implanted to the carotid arteries of the same animals for 2 weeks (n=3) and 12 weeks (n=3), were morphologically investigated by transmission electron microscope. They were quantitatively evaluated by classifying the SMCs in hybrid media into 3 phenotypes such as the synthetic, the intermediate and the contractile states. Before implantation, SMCs were of the representative synthetic phenotype, which were spherical and intracellularly filled with synthetic organelles, such as rough endoplasmic reticulums, free ribosomes, Golgi complexes and mitochondria. After 2-week implantation, SMCs were bipolarly elongated but still remained in the synthetic phenotype. After 12-week implantation, spindle-shaped SMCs had an increased content of contractile apparatus such as myofilaments, dense bodies and basement membranes. The quantitative investigation showed that the populations of 3 phenotypes of SMCs at 2 weeks were 50.5, 41.8 and 7.7% for synthetic, intermediate and contractile, respectively. After 12-week implantation, they were 9.9, 26.2 and 63.8%. These indicate that SMCs in hybrid media were reverted from the synthetic to the contractile state in a few month in vivo. Thus, the hierarchically structured hybrid vascular prostheses are expected to provide a physiological function after implantation.
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K. KANDA, T. OKA, T. MATSUDA
1994 Volume 23 Issue 3 Pages
799-802
Published: June 15, 1994
Released on J-STAGE: October 07, 2011
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Ring-shaped hybrid medial tissues were constructed by 3-dimensionally incorporating the bovine aortic smooth muscle cells (SMCs) into type I collagen gels. The tissues were subjected to 3 different modes of mechanical stresses; isotonic stress (control), isometric stress (static stress) and periodic stretch and relaxation with 10% amplitude at 60RPM frequency (dynamic stress). After stress-loading for 4 weeks, the tissues were morphologically investigated. In control tissues, spherical SMCs and collagen fiber bundles had no preferential orientation. On the other hand, in stress-loaded tissues, bipolarly elongated SMCs and dense collagen fiber bundles were aligned parallel to the direction of stretch, irrespective of static or dynamic stress-loading. Ultrastructural investigation revealed that, in control and statically stressed tissues, SMCs were almost filled with synthetic organelles such as rough endoplasmic reticulums, free ribosomes, Golgi complexes and mitochondria. In dynamically stressed tissues, SMCs had an increased content of contractile apparatus such as myofilaments, dense bodies and basement membranes. These results indicate that phenotypic modulation of SMCs from the synthetic to the contractile state as well as cellular and biomolecular orientation could be induced by the physiologically resembled dynamic environment in vitro.
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