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[in Japanese]
1993 Volume 22 Issue 2 Pages
267
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
JOURNAL
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M. GOTO, A. KOBAYASHI, H. YURA, A. MAEDA, K. KOBAYASHI, T. AKAIKE
1993 Volume 22 Issue 2 Pages
269-273
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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A lactosecarrying polystyrene (PVLA) modified with
125I was found to have highly specific interaction with hepatic parenchymal cells in vivo. This specific interaction with liver cells is the result of the recognition of the galactose moieties on the polymer by asialoglycoprotein receptors on hepatocytes. An important physical property of the amphiphilic PVLA is the ability to form super molecular assembly in aqueous solution due to the presence of water soluble lactose residue on hydrophobic polystyrene backbone. We demonstrated that PVLA could form inclusion compound with various model drugs and could serve as a drug carrier with hepatocyte-targeting ability. The high specificity in tissue distribution of radioactivity labeled PVLA found in this study supports our claim that PVLA may be used as highly specific targeting super molecular assembly for in vivo drug delivery to liver.
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K WAKI, Y KOYAMA, K KATAOKA, M YOKOYAMA, T OKANO, Y SAKURAI
1993 Volume 22 Issue 2 Pages
274-279
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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Glucose-responsive insulin release systems have been investigated using interpenetrating polymer network (IPN) and semi-IPN gels composed of poly(N, N-dimethylacrylamide-co-methacrylamidophenylboronic acid) and polyvinyl alcohol. Boronic acids are known to reversible bind molecules containing cis-diols (e. g., glucose). The swelling degree of semi-IPN gels containing phenylboronic acid groups was enhanced with increasing glucose concentration. We considered that binding of polyvinyl alcohol with phenylboronic acid residues was substituted with glucose, resulting in the swelling of the gel. Reversible swelling/deswelling of the gel responding to the stepwise change in glucose concentration was observed, confirming the reversibility of this system. Permeation experiments of fluorescein isothiocyanate-labeled insulin (FITC-insulin) were performed using membranes containing 10mol% boron monomer. Addition of glucose lead to swelling of the gel, resulting in an increase in the permeation rate of FITC-insulin. We concluded that the controlled release of insulin from glucose-responsive gels containing boronic acid is achievable.
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N YUI, T OKANO, Y SAKURAI
1993 Volume 22 Issue 2 Pages
280-285
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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Inflammation responsive degradation of crosslinked hyaluronic acid (HA) gels and regulated release of lipid microspheres (LM) dispersed in the degradable matrices of crosslinked HA gels were studied in vitro and in vivo. The HA gels were specifically degradable by hydroxyl radicals among active oxygen species, and LM dispersed in the crosslinked HA gels was released in proportion to the degradation of crosslinked HA gels. Furthermore, the crosslinked HA gels were degraded in response to inflammation in vivo although being stable in normal healthy conditions. These results suggest that the crosslinked HA gels with LM are promising as substrates for inflammation responsive drug delivery.
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S KYO, T MOMTOYAMA, N MIYAMOTO, K UEDA, K HASEGAWA, H ASANO, S KIMRA, ...
1993 Volume 22 Issue 2 Pages
286-291
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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63 patients were performed circulatory support with mechanical assist circulation in the past 12 years. Survival ratewas 7.5% (3/40) in the veno-arterial bypass (VAB) support, 37.5% (3/8) in theleft atrioarterial support (AAB), 42.9% (3/7) in the VAB+AAB support, and 37.5% (3/8) in the ventricular assist device (VAD) support. Percutaneous cardiopulmonary support (PCPS) was performed on 6 patients (AAB:4, VAB:2) with cardiac arrest (4 pts) and non-surgical cardiogenic shock (2 pts). One patient was survived and two patients were recovered from shock and surgery was performed, one patient with cardiac arrest due to dilative cardiomyopathy was sequentially supported by VAD for bridge to heart transplantation. In conclusion, percutaneous AAB using transseptal puncture permits rapid start of left heart bypass support, thus can be an effective alternative for non-surgical cardiogenic shock patients.
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M SHIONO, GP NOON, Y NOSE, T HASEGAWA, S SHINDO, Y ORIME, S YAGI, Y SE ...
1993 Volume 22 Issue 2 Pages
292-299
Published: April 15, 1993
Released on J-STAGE: December 02, 2011
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As of 1992 pneumatic ventricular assist device (VAD) has been applied for profound heart failure in 16 postcardiotomy patients. Average assist duration was 86 hours and left ventricular assist device in 13 patients and right ventricular assist device in 3 patients. Weaning rate from the device was 66% and survival rate was 20%. Causes of death were multi-organ failure in 40%, ventricular failure in 25%. Infection and thromboembolic complications were not observed during support. Optimization of assist flow has been achieved by monitoring hemodynamic and echocardiographic data. Hemodynamic criteria for weaning from the device has also been established; cardiac index>2.5L/min/m
2, pulmonary capillary wedge pressure < 15mmHg, etc. Monitoring of the coagulation system has also been important for avoiding multi-organ failure and getting long-term survival. The results have suggested that this system is versatile for profound heart failure in postcardiotomy setting and could also be applied as a short-term or intermediate-term device for emergent setting and bridge-to-transplant patients. We reviewed our experience using the Nippon Zeon ventricular assist system and introduced clinical experience of ventricular assist device application of Baylor College of Medicine in Houston, U.S.A. and discussed about the problems of assist devices.
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T. NAKATANI, M. SAKAKI, H. ANAI, Y. TAENAKA, M. KINOSHITA, H. AKAGI, H ...
1993 Volume 22 Issue 2 Pages
300-305
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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Abdominally placed left ventricular assist system (LVAS) was developed and evaluated in chronic animal experiments using 9 adults goats. This LVAS showed easy applicability and stable hemodynamic condition over 13 weeks. There was no thromboembolic symptoms and no signs of infection around the pump pocket except one. Effect of cardiomyoplasty (CMP) on ventricular function was evaulated in 4 adult goats with preconditioning of left lattissimus dorsi muscle (LDM). Mean pulmonary arterial pressure, right ventricular ejection fraction, and cardiac output showed a tendency to increase. We considered that this LVAS is promising for long-term use and that CMP could play an important part to improve the right ventricular funtion. For the treatment of profound heart failure, LVAS and CMP shoud be selected according to the severity of heart failure.
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T. MASUZAWA, M. KINOSHITA, Y. TAENAKA, T. NAKATANI, H. AKAGI, H. TAKAN ...
1993 Volume 22 Issue 2 Pages
306-309
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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A model of the cardiovascular system was developed using a neural network technique. A treadmill exercise experience was performed to obtain the physiological signals during the exercise with a goat. The blood pressure catheter and blood flow prove were implanted in the chest and the exercise tests were performed after two weeks of the operation. The model to estimate cardiac output from heart rate, mean arterial pressure, mixed venous saturation and physical activity that were obtained from the exercise experience was constructed based on a neural network technique. A three-layer back-propagation network, which has the input layer with forty two cells, the hidden layer with thirty two cells and the output layer with 10 cells, was used to construct the model. Five hundred and forty six sets of data were used for learning process of the network. Seventy sets of the learning data and sixty six sets of data which were not used for learning were used to evaluate the performance of the cardiac output estimation. The correlation coefficient between the learning data and real cardiac output was 0.965 (p<0.001) and that for the non-learning data was 0.869 (p<0.001) and the feasibility of the neural network for modeling of cardiovascular system was confirmed.
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M. UMEAU
1993 Volume 22 Issue 2 Pages
310-315
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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A mechanical circulatory system which can simulate the hemodynaic functioning as well as cardiac valve functioning in real world conditions is currently under development. This system consists of a cone-shaped left ventricle (LV) and leaflet valves, both of which were made from segmented polyurethane. A globeshaped left atrium (LA) and a U-shaped aorta (Ao) were made of silicone. Supplementary compliance tanks and servo-controlled valves were incorporated in the circulatory model. Then, natural aortic waveforms including peaking and steepening phenomena could be obtained in the model. After the modification of the software of the pneumatially-operated heart driver, the artificial atrium could be slightly collapsed prior to the contraction of the ventricle. Consequently, similar behavior of the valve implanted at the mitral position could be simulated. After several trials to simulate cardiac failure in the model, it was noted that the Emax curve obtained from the current model was very similar to that of the natural heart. As the Emax curve simulated by the new system gave a better understanding of clinical hemodynamic data, the true valve function can be deferentiated from the cardiac function findings obtained through the simulation data on heart valves. This ability to simulate natural cardiac fanctioning is the main advantage this system has over other simulation systems, including mathematical or electrical models.
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M KITAMURA, O TAGUSARI, T AKIMOTO, H NIINAMI, K YAMAZAKI, M ENDO, A HA ...
1993 Volume 22 Issue 2 Pages
316-319
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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Fifteen mongrel dogs received the isolated LVAS with left ventricular uptake (LV group: 9 dogs) or with left atrial uptake (LA group: 6 dogs). Four of 9 dogs in LV group and 3 of 6 dogs in LA group showed pulmonary hypertension by filariasis. As a model of cardiac failure, left ventricular infarction (LVI) and biventricular infarction (BVI) were made by multiple ligation of coronary arteries. And finally, ventricular fibrillation (VF) was induced with DC fibrillator. High pulmonary vascular resistance (PVR) over 640 dyne·sec·cm
-5 related poor circulatory support during BVI or VF in 3 dogs of LA group and during VF in 4 dogs of LV group. In the remaining 5 dogs with low PVR in LV group, the isolated LVAS with LV uptake was capable of maintaining the sufficient circulation under VF condition.
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M MINESHIMA, T HOSHINO, K ERA, S NAKAZATO, K KUBO, T SANAKA, S TERAOKA ...
1993 Volume 22 Issue 2 Pages
320-324
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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Adequate dialysis for each patient was established through a 1-compartment model for urea. 78 subjects with CRF who received HD treatments 3 times a week participated in this study. Blood samples were collected at pre- and post-treatment on midweek-dialysis and pre-treatment on weekend dialysis in a week. Substituting BUN values obtained from samples into the analytical solutions of 1-compartment model yielded Kt/V, G/V and estimated time-averaged concentration(TACest) for urea. Clinical TAC value(TACclin) defined as the timeaveraged BUN of samples has a good correlation with TACest as follows: TACclin=0.643 TACest+13.1 (r=0.898). TACclin values, however, indicate about 8.2% smaller than TACest values because changes of V and G were ignored in the 1-compartment model.
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K YANAGI, H MIYOSHI, N OHSHIMA
1993 Volume 22 Issue 2 Pages
325-329
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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In order to estimate performance of a hybrid-type artificial liver support system (ALSS) utilizing cultured hepatocytes quantitatively, rate equations describing activity change of hepatocytes and a compartmental mass transfer model were established. Experimental verification of this model was performed in a series of experiments, i. e., dish culture experiments, ex vivo perfusion experiment using rotating-disk type ALSS and in vitro high density culture of hepatocytes using porous material. In these experiments, compartmental model was useful to evaluate metabolic activities of hepatocytes, and agreement between observed values and simulated values based on this model was good for ex vivo perfusion experiments.
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Y. SHIMAZAKI, JC. CHANG, M. KANEKO, S. NAKANO, H. MATSUDA
1993 Volume 22 Issue 2 Pages
330-332
Published: April 15, 1993
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Ventricular systolic function and myocardial energetic efficiency were assessed in reperfused dog hearts after 30 minutes ischemia which were heterotopically transplanted. Myocardial oxygen consumption under unloaded condition returned to normal after 60 minutes of reperfusion. However, venricular function indexed as preload recruitable stroke work (PRSW) and myocardial energetic efficiency were 75% and 78% of the control at 18 hours after ischemia. This unloaded reperfused heart may be a useful model for assessing ventricular performance and energetic efficiency in failing hearts.
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A. YANASHITA
1993 Volume 22 Issue 2 Pages
333-335
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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Many different kinds of models are utilized for artificial organ research. Choice of these models usually depends on researchers' background no matter which model is suitable. The author experienced to widen his views when he used animal and mathematical models with the same emphases for analyzing mechanisms of peritoneal mass transport. It had been a common knowledge that the peritoneal mass transfer occurred in proportional to the product of peritoneal surface area and the concentration difference between blood and the dialysate solution; however, it was proved to be incorrect by a canine in vivo experiment. On the other hand, it was the same animal experiment that made the author develop a new mass transfer model in which peritoneal blood flow rate was taken into account. This mathematical model predicted many important results, which would give nice pieces of information on future research. Integration of animal and mathematical models could be a “model” relationship in artificial organ research.
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Junihi UTOH, Hiroaki HARASAKI
1993 Volume 22 Issue 2 Pages
336-338
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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In vitro effects of heat on polymorphonuclear cell (PMN) function were studied. To observe the PMN phagocyt is function at various temperatures, PMN from healthy adult donors were incubated with serum-opsonized fluorescent latex particles at 37°C for 1 hour and then observed for their phagocytic activity. At 44°C and above, the function significantly decreased. Next, to determine the critical temperature and duration of exposure that would irreversibly damage the function, PMN were preincubated at 37-46°C for 5-30 minutes before a standard phagocytosis assay. The function was significantly depressed after 30 minutes at 44°C or 10 minutes at 46°C. In conclusion, PMN phagocytosis was irrevesibly and time-dependently damaged when incubated at and above 44°C.
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Mizuno ISANU, Taniguchi MASATETSU, Yura JIJO, Nakamura SATOSHI, Aoki H ...
1993 Volume 22 Issue 2 Pages
339-343
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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Hydroxyapatite has superior compatibility with human tissues. and has been utilized for percutaneous devices and orthopedic and dental uses. Hydroxyapatite particles (HAp) contains many micropores and extensive surface areas. The usefulness of intraperitoneal administration of Lentinan-Loaded Hydroxyapatite particles (HAp-LNTN) was evaluated using a Donryu rat model of cancerous peritonitis due to intraperitoneal injection of AR 130 carcinoma.
HAp as a drug carrier are the form of porous particles 30-50μm in diameter. The drug delivery system consisted of HAp-LNTN, containing 200mg of HAp and 0.5mg of LNTN. We found that intraperitoneal administration of Hap-LNTN was effective in prolonging the surslval of rates bearing AH-130 carcinoma in the peritoneal cavity, from day 35 to day 50. The pharmacokinetics of Lentinan following i. p. administration were also studied. Serum levels of HAp-LNTN were elevated for 24 hours compared with free-LNTN. Results suggest that the efficacy of anticancer drugs may be enhanced by utilizing HAp as a drug delivery system.
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A AMEMIYA, S NAKANO, Y MIYAMOTO, JC CHANG, H MATSUDA, Y ISHIHARA, H KI ...
1993 Volume 22 Issue 2 Pages
344-347
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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A new membrane oxygenator (LH-760) was developed and assessed for gas transfer and blood compatibility. The oxygenator is made of silicone hollow fiber. Therefore this oxygenator may have a constant gas exchange performance and a superior blood compatibility to other oxygenators made of microporous mambrane. This device was used to conduct cardiopulmonary bypass (CPB) in 10 patients. Blood gas analysis and hematological examination were carried out during CPB. Blood gas was maintained at high PO
2 and acceptable PCO
2 levels throughout CPB. Platelet count at the end of CPB was maintained at 75% of the initial value. Fibrinogen decreased temporarily following the start of CPB and
then recovered by the end of CPB. FOP increased during the early period of CPB but did not change there after. C
3a increased during CPB while C
3, C
4, CH
50 showed little change. These findings show this oxygenator has adequate gas exchange and good blood compatibility.
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T. NATSUME, N. OKUMURA, Y. SHIMIZU
1993 Volume 22 Issue 2 Pages
348-352
Published: April 15, 1993
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We developed a new collagen hemostatic agent which has cotton-like fibrous form (CC). It has previously been shown to effectively control bleeding from experimental splenic injuries produced in dogs. In this study three different CC in fibril diameter, 10-20, 20-50, and 50-80μm were examined. It was found that the CC, 20-50mm in diameter, had the most remarkable hemostatic properties.
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T KIYOTANI, Y SHIMIZU, T NAKAMURA, E OZEKI
1993 Volume 22 Issue 2 Pages
353-358
Published: April 15, 1993
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We synthesized Methyl-oligo-lactate (LTM) for absorbable bone wax. The hemostatic effectiveness and effect on osteogenesis of LTM were compared with those of conventional bone wax. Experimental animals used were 12 male white rabbits. On each side of the iliac bone, three adjacent cavities (φ3mm) were made with a drill. The two cavities on each side, were filled with LTM and bone wax respectively. The another cavity was remained untreated for control. Two animals were sacrificed at 1, 2, 4, 8, 12 and 16 weeks, respectively. In two rabbits LTM and bone wax were implanted in the lumber muscle, and sacrificed after one week. In the operation LTM showed sufficient hemostatic effect. On histological evaluation, tissue reaction of LTM was minimal, whereas that of control bone wax was sevier; sugessting harmlessness of LTM. However, the large part of LTM still remained even after 16 weeks. Therefore more rapid absorbable type of LTM are desirable for more effective bone wax.
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H. SHIMADA, KI. HIRAI
1993 Volume 22 Issue 2 Pages
359-363
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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The nerve grafts which consist of lamininfibronectin double coated collagen fiber bundles were used for providing regeneration of rat peripheral nerves. A 1-cm defect of the right sciatic nerve was filled with a graft. Thirty days after implantation, many new nerve fibers extentended along collagen fibers. In control grafts which include only non-coated collagen fibers, many fibroblasts had invaded into gaps among the collagen fibers and disturved nerve elongation. After 60 days, regeneration of both moter and sensary nerves was confirmed electrophysiologically. The number of the regenerated axons in the grafts was apparently larger than that of control grafts. Laminin promoted the elongation of regenerated axons and fibronectin inhibited excessive invasion of fibroblasts. Therefore, these grafts seemed to be competent for peripheral nerve regeneration.
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G. LEE, T. NAKAMURA, Y. SHIMIZU, K. TOMIHATA, Y. IKADA, K. ENDO
1993 Volume 22 Issue 2 Pages
364-369
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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In order to evaluate the regeneration of resected nerves, a dehydrothermally treated gelatin tube was used to repair 10-mm defects in the sciantic nerve of rats. As a control, a gelatin tube treated with glutaraldehyde was used. Histological examination using Osmium, Bodian and anti-S-100 protein staining at 2 months and at 4 months after the operations revealed that the regenerated axons reached through the gelatin guide-tube to the distal end.
Motoneurons of the ventral horn as well as afferent nerve terminals in the dorsal horn of the spine were stained both retrogradely and anterogradely with WGA-HRP, indicating nerve regeneration through the bridged area. With regard to nerve function, the electromyogram and cerebral somatosensory potentials at 2 months showed functional recovery.
In the controls, no regeneration was observed. These results indicate that this dehydrothermally treated gelatin tube is a promising biomaterial for use as a nerve-conductive tube for inducing nerve regeneration.
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T FURUZONO, A KISHIDA, M AKASHI, I MARUYAMA, T MIYAZAKI, Y KOINUMA, T ...
1993 Volume 22 Issue 2 Pages
370-375
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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A novel multiblock copolymer (PAS), consisting of aromatic polyamide (aramid) and poly (dimethylsiloxane) (PDMS: Silicone) synthesized by polycondensation, is expected to have desirable properties of both polymers. In this study, the surface characteristics, oxygen permeability and blood-compatibility of PAS films were investigated, and the hollow fiber which was made of PAS was prepared. From the results of these experiments, it was found that the silicone block was condensed at the outermost surface of PAS film of all range of PDMS content. The permeability coefficients to oxygen of the films containing over 53 wt% of PDMS were very high enough to be useful as oxygen permeable membrane. The interaction between platelets and PAS was very weak. The silicone block condensed a the surface of PAS film resulted in the endowment of bio-inertness to PAS. Because of its unique properties, PAS is expected to be useful as a novel biomaterial.
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H MIWA, T MATSUDA, MJ MOGHADDAM
1993 Volume 22 Issue 2 Pages
376-379
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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We are developing the tissue adhesion prevention technology based on photocurable mucopolysaccharides. Mucopolysaccharides were partially derivatized with photoreactive groups to attain photocurability. Ultraviolet irradiation produced water insoluble gels via intermolecular photodimerization of photoreactive groups. Photocured films with lower degrees of substitution (DSs) exhibited the high water swellability, whereas higher DS resulted in reduced swellability. Little cellular adhesion was observed on photocured films with low DSs. In vivo experiments, photocured film exhibited the tissue adhesion preventionability as well as biodegradability. As a photocurable mucopolysaccharide solution was coated on tissues, a viscous solution was converted to hydrogel by UV-irradiation. The in situ gelation of photocurable solution is expected to be useful in endoscopic surgery.
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K. ABE, K. SUZUKI, T. OKANO, Y. SAKURAI, M. SUGAWARA, T. BORIC
1993 Volume 22 Issue 2 Pages
380-385
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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In order to find an inhibitory mechanism of platelet activation on HEMA-St block copolymer surfaces with an alternate lamella structure, the platelet response which pre incubated at 37°C for one hour to the block copolymer surfaces was analyzed at the ultrastructural level by scanning (SEM) and transmission electron microscopy (TEM). Especially, TEM data of platelets after contact with the block copolymer surfaces were quantified by image analyzer. PSt, HEMA-St random copolymer surfaces were prepared as polymers for comparison. The interaction between the platelets and the polymer surfaces (diameter of polymer beads, 150μm) was employed by experimental equipment under 37°C conditions based on the microsphere column method (column length, 10cm; column inner diameter, 3mm). The flow rate was carried out at 0.1ml/min for 15 minutes. The platelets after contact with the polymer surfaces were analyzed by TEM. And then, a number of storage granules per 1μm
2 in unstimulated platelets and platelets after contact with the block copolymer surfaces were quantified by image analyzer. The platelets adhered to the polymer surfaces for an incubation period of 3 hours were analyzed by SEM and TEM. As a result, it was found that the block copolymer surfaces inhibit remarkably platelet activation in any case of enhancing platelet response activity by means of preincubating platelets at 37°C for one hour compared to that of PSt and the random copolymer surfaces. On the TEM image analysis of the platlets, the number of platelet storage granules on the block copolymer surfaces didn't indicate any significant difference when compared to that of unstimulated platelets. It was suggested that the block copolymer surfaces have an active inhibition effect on platelet activation.
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Hiroyasu MISUMI, Yasuharu IMAI, Kazuaki ISHIHARA, Syuuichi HOSHINO, Ka ...
1993 Volume 22 Issue 2 Pages
386-389
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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We examined late results of consecutive 45 patients who underwent external conduit repair for congenital heart anomalies at Tokyo Women's Medical College from 1975 through 1986. The cardiac anomalies included tetralogy of Fallot (16 patients), d-transposition of the great arteries (17 patients), atrioventricular discordance (15 patients), and other cardiac anomalies. Follow-up period ranged from 2 months to 15 years and 9 months (average 10 years and 5 months). Actuarial survival rate was 88% at 10 years, and 84% at 16 years after operation. There were 6 late deaths in the follow-up period: two in atrioventricular discordance group from heart failure, two by sudden death presumably due to rhythm disturbance, and the other two from severe hypertensive obstructive change or septic shock. Fifteen patients required a replacement of external conduit due to stenotic degeneration between 4 to 16 years after initial operation. All but one patients survived the reoperation. All late survivors were in class I or class II of New York Heart Association. This study demonstrates that stenotic degeneration is likely to occur within 10 years in most patients who received Hancock composite graft in reconstructive surgery for congenital hear anomalies.
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-Safety of Metallic Materials at MRI-
T. NAKAMURA, K. HAYAKAWA, Y. SHIMIZU, K. FUJIWARA, N. OKUMURA, T. ARIY ...
1993 Volume 22 Issue 2 Pages
390-393
Published: April 15, 1993
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Examination. Temperature change, motion and electric current of metallic samples were checked. Metallic materials examined were as follows; coils (S=20cm
2) made from medical grade Ti, SUS316, Ti-6A1-4V, Ti-Ni and Fe, and large Fe coils (S=1500cm
2) as well as powdery Fe, Fe
2O
3, and Fe
3O
4. MRI device used was MRT 50A (0.5T). Scanning condition was spin-echo and field-echo similar to clinical usages. No significant rise of temperature in metallic materials enough to cause burns could be measured. In case of large Fe coil (S=1500cm
2), induction of electrical current during imaging was 0.001-0.003mA (30.0-70.0mV). In this condition, the gradient and RF magnetic field could not induce a current enough to raise the temperature of the coils for causing heat injury.
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Y. NAKAYAMA, T. MATSUDA
1993 Volume 22 Issue 2 Pages
394-397
Published: April 15, 1993
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The authors report a new photochemical technique for the fixation of hydrogels onto the surface of fabricated devices. The preparative method consisted of simultaneously enabling hydrogel formation and its surface fixation, both of which are based on photochemistry. First, a photoreactive poly (m-azidostyrene) was applied as an adhesive coating to substrates. Subsequently, a photocrosslinkable cinnamated hydrophilic copolymer of poly (N, N-dimethylacrylamide)-poly (2-cinnamolyethyl methacrylate) was applied as an additional coating. Ultraviolet irradiation resulted in the formation of hydrogel and in its chemical fixation onto the substrate, which were induced by photocrosslinking due to intermolecular dimenzation of cinnamoly groups and by covalent bonding due to photoreactivity of phenylazide groups, respectively. No delamination was found by vigorous washing with water. These were confirmed by ESCA measurements. For hydrogelated surfaces with higher degrees of swelling, significant inhibition of adhesion of platelets and marked prolongation in blood coagulation time were observed When heparin was immobilized in hydrogel, potent anticoagulant activity was obtained
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-STUDY OF NEOINTIMA FORMATION
H. KAJIWARA, Y. NOISHIKI, K. HIRANO, Y. ICHIKAWA, M. ISHII, T. KOSUGE, ...
1993 Volume 22 Issue 2 Pages
398-402
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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A cardiac wall substitute made of Dacron fabric prosthesis sealed with autologous tissue fragments was developed: An animal study showed rapid neointima formation. A piece of subcutaneous adipose tissue was minced and stirred into saline thereby creating a tissue suspension. A Dacron vascular prosthesis (Prosity: 4, 000ml/cm
2/min at 12OmmHg) was clamped in its center with a haemostat. The tissue suspension was injected with pressure into one half of the prosthesis. Fresh blood was proured into it repeatedly to seal the other half by preclotting. It was cut longitudinally. By this procedure, a cardiac wall substitute was sealed with tissue fragments in one half and preclotted with blood on the other. The grafts were implanted into the right ventricular outflow tracts in 8 dogs. Two weeks after implantation, red thrombus adhered on the tissue fragments section. Light microscopical observation showed complete neointima formation at the tissue fragments area but thrombus layer at the preclotted area. These results indicated that the sealing of the fabric prosthesis with autologous tissue fragments was an ideal method for a cardiac wall substitute.
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M. TAKATSUKA, T. MATSUDA
1993 Volume 22 Issue 2 Pages
403-406
Published: April 15, 1993
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This paper describes a novel photo-induced surface process technology providing a given biocompatibility on a given part of complex-shaped device. The material designed for this purpose was poly (N-acryloyloxysuccinimide) partially derivatized with N-(2-aminoethyl)-4-azidobenzamide. This bifunctional polymer was cast on a polymeric surface, followed by UV-irradiation. Then, the immersion into a buffer solution of a protein resulted in chemical fixation of protein. This was evidenced with the ESCA spectral study. Hydrophilic group-, cell adhesive peptide GRGDS- and fibronectin-fixed surfaces were prepared; the former were found to be free from cell adhesion, whereas the latter two were cell adhesive. Since the derivation of activated ester group on a polymer surface takes place only on an irradiated portion, a given biocompatible surface design at a given part of complex-shaped device was found to be feasible.
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T. SUGAWARA, T. MATSUDA
1993 Volume 22 Issue 2 Pages
407-411
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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This paper describes the control of cellular adhesion, migration and orientation responces on photochemically microprocessed surface. The method is based on the photochemical reaction of phenyl azide group. Hydrophilic photoreactive copolymer, poly (m-azidostyrene-co-N, N-dimethyl acrylamide), which underwent chemical bonding with polymer substrates upon UV-irradiation was coated on a tissue culture dish and photomasks, which have narrow slits(20-130μm), were placed. After UV-irradiation, the surface was vigorously washed to remove unbound fractions and endothelial cells were seeded on microprocessed surfaces. Microscopic observation of the surface indicated that the cells were adhered and migrated only at non-irradiated portion. The migration process was monitored by a portrait analysis system (PIAS LA-500) and was quantitatively determined. The width of migration of cells showed a good agreement with the width of photomask's slits and the migration rates of the cells were essentially the same as that on non-modified surface. The cells on the microprocessed surfaces possessed a long and narrow morphology and were oriented parallel to the length of the slits used. These results indicated that the adhesion area, migration direction and orientation of cells could be controlled by this method featured with microns-order precision. This method also allows us to provide quantitative information of kinetics of migration process and morphogenesis on microprocessed surface.
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M. TAKATSUKA, T. MATSUDA
1993 Volume 22 Issue 2 Pages
412-416
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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Our previous report showed that albumin conjugated with the peptide, Gly-Arg-Gly-Asp-Ser (GRGDS) which contains RGD tripeptide sequence identified as the minimum core cell adhesive peptide, exhibited cellular adhesive responses (adhesion, spreading and migration) similar to those of fibronectin and vitronectin. In this paper, we determine the interaction strength between cell receptor-ligand from the dosedependent inhibitory response by addition of GRGDS into a medium. The result showed that the half-inhibition concentration of endothelial cell adhesion on GRGRDS-conjugated albumin was much lower than those on vitronectin and fibronectin. Little appreciable change was observed when the peptides identified as accessory adhesive sites of fibronectin were derivatized on albumin. This indicates that, as compared with natural counterparts, GRGDS-conjugated albumin interacts quite weakly with endothelial cells.
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H TSUCHIDA, SE WIKSON, R KOWLIGI, T NAGAE, S ISHIMARU, K. FURUKAWA
1993 Volume 22 Issue 2 Pages
417-420
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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An expanded polytetrafluoroethylene (PTFE) graft can be made stretchable by elastomer coating with longitudinal compression. Using polyurethane as the elastomer, we produced elastomer end-coated stretch PTFE grafts (elastomer PTFE grafts) and implanted them in twelve female adult mongrel dogs to assess handling characteristics and healing. Each dog had bilateral aortoiliac grafts placed, one a standard PTFE and the other an elastomer PTFE graft. The grafts were 7-Scm in length and 6mm in diameter. The elastomer PTFE grafts showed superior longitudinal elasticity, retention of shape, no graft tearing with suture tension and no needle hole bleeding. The grafts were harvested at intervals to 120 days postoperatively. Satyisfactory patency was obtained with both standard (8/10) and elastomer PTFE grafts (9/10) at 90-120 days. No significant difference in the thichness of intima and the length of pannus ingrowth wes noted between the standard and elastomer PTFE grafts. Complete separation from the surrounding tissue because of no outer tissue incorporation was seen at the elastomer treated graft segments as opposed to the well incorporated untreated segments. In conclusion, the elastomer PTFE graft provided excellent handling characteristics without detracting from patency; however, the lack of outer tissue incorporation may be a potential disadvantage in its clinical use.
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K. HIRABAYASHI, M. SAITOH, T. MITSUI, M. KOSAMA, M. HORI
1993 Volume 22 Issue 2 Pages
421-425
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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Influence of fibril length upon ePTFE graft healing has not been investigated in detail. The purpose of this study was to determine the dependence of total graft healing on the four types of fibril length (20μm, 40μm, 60μm, 90μm) ePTFE grafts. EPTFE grafts of different fibril length were implanted into the abdominal aorta of rats(n=5 for each group). After 5 weeks, the grafts were harvested and examined for total graft healing by lightmicroscopy and SEM. The content of amino acids contained in grafts was measured. The neoendothelial coverage was related to the fibril length, and was better in 60μm and 90μm grafts than in 20μm and 40μm grafts. ‘Neomedia’ were mainly composed of spindle-shaped cells and lymphocytes, and its healing was better in 60μm and 90μm grafts. But host response to graft surface on the ‘neoadventitia’ was more sever in 40μm, 60μm and 90μm grafts than in 20μm grafts, that is, several foreign body giant cells could be found in long fibril length groups. The amount of hydroxyproline was also related to the fibril length, but no significant difference could be found on the ratio
of amino acids.
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-the comparison of reinforced expanded PTFE (REP) and autologous saphenous vein (ASV) graft-
S Ohba, K KOSUGA, K URAGUCHI, K YAMANA, K KENMOCHI, Y KUBOTA, M MOMOSA ...
1993 Volume 22 Issue 2 Pages
426-429
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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Between 1986 and 1991 we performed F-P bypass procedures of thirty six patients fourty four limbs using REP and ASV with above knee anastomosis for ASO. The background factors of both groups were not different except their ages. As postoperative medication we used, respectivevly, warfarin (80.0%, 33.3%) and antiplatelet(100%, 90.5%). In REP group, fifteen patients sixteen limbs, the cumulative patency rates were 100% at one year, 80.0% at two years, 80.0% at four years. The late graft occlusion occured in two patients, one of them was probably due to intimal hyperplasia at the anastomosis site, other one was presumably due to the progress of distal lesion. On the other hand, the patency rates were 100% at one year, 96.3% at two years, 87.5% at four years, 82.4% at five years in ASV group, twenty one patients twenty eight limbs. REP as the material of F-P bypass with above knee anastomosis for ASO, was not significantly different from ASV in patency rate and was revealed usefull.
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H. IDE, T. CJINZEI, I. FUJIMASA, T. INO, H. ADACHI, A. MIZUHARA, A. YA ...
1993 Volume 22 Issue 2 Pages
430-433
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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A new Titanium thin wall tube with two external fixation ring inserted between Dacron grafts to connect them was developed to help simplifying the operative procedure of thoraco - abdominal aortic reconstruction.
Physical stress test of three kinds revealed its tolerance as a vascular prosthetic implant. Especially, intraluminal pulsatile flow stress test of 260×10
4 times utilizing a mock circulation circuit showed no obvious Dacron graft damage in the ring-graft interface.
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N. SUZUKI, Y. OKUMURA, K. KATAMI, T. KUMADA
1993 Volume 22 Issue 2 Pages
434-439
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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We studied the process of vascular graft calcification through histopathological examination of expanded polytetrafluoroethylene (EPTFE) of different fibril lengths(15-90μm) and Dacron grafts implanted to the carotid arteries of normal dogs. Calcific deposits were observed in a hyalinized connective tissue within the graft wall and a pseudointima 3 months after implantation. Immunohistochemical examination demonstrated that the hyalinized tissue consisted mainly of dense deposits of type I collagen, which might be secreted by fibroblasts infilterating from connective tissues around an outer wall of the grafts. Additionally, EPTFE grafts of longer fibril lengths significantly reduced both hyalinization and subsequent calcification which occured within the graft wall. In conclusion, vascular graft calcification is most frequently associated with an excess deposition of type I collagen fibers, resulting from fibrotic healing in small internodal space of EPTFE grafts.
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K YAMAMOTO, Y NOISHIKI, T KPSUGE, M ISHII, Y ICHIKAWA, M MO, H KAJIWAR ...
1993 Volume 22 Issue 2 Pages
440-444
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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We have developed a pure collagen coated ultrafine polyester fiber graft (CUFPG), which was cross-linked by a hydrophilic polyepoxy compound. CUFPG was compared with the Gelseal Triaxial® graf t in several properties. Porosity was Oml in both prosthesis. The quantity of impregnated gelatin in Gelseal® was seven times that of collagen in CUFPG. In addition, the gelatin of Gelseal® was easily detached from the inner surface and it had 11.33pg/cm
2 endotoxin at 37°C 72 hours in pyrogen test. On the other hand, the collagen of CUFPG did not detached and it had no endotoxin. In a cell culture study there was no remarkable difference in cell growth on both prosthesis. In conclusion, CUFPG is thought to be a more safety vascular prosthesis more than the graft sealed with gelatin “Gelseal Triaxial®”.
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Shinichi SATOH, Satoshi NIU, Keiichi KANDA, Zirou HIRAI, Akiyuki TAKAH ...
1993 Volume 22 Issue 2 Pages
445-448
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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For surgical reconstruction of thoracic and abdominal aorta and peripheral artery, we use a straight and Y shaped Toray graft® which was made of an ultrafine polyester fiber (UFPF). Toray grafts® were implanted for 52 cases. This prosthesis has woven structure and has properties of healing and pliability, In addition its porosity is 100ml/min/cm2, . Entangled UFPF prevented blood leakage and accelerated its healing. In clinical use for thoracic aorta we treated this proshtesis with heated, denatured albumin. For abdominal aorta this prosthesis was preclotted for about 2 min, after proximal aorta was anastomosed For peripheral arteries any pre- or post- treatments for this prosthesis was not performed. Its fittness and handling in suture to the aorta were distinguished compared to another woven Dacron graft.
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K. KATAMI, M. HAMAGUCHI, H. OINUMA, T. KUMADA
1993 Volume 22 Issue 2 Pages
449-454
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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We determined the effect of fibril length on luminal clot-layer formation and subsequent neointimal healing of expanded polvtetra-fluoroethylene (EPTFE) grafts. Twomm internal diameter EPTFE grafts(3cm in length) with fibril length of 15, 30, 60 and 90μm, were implanted into the carotid arteries of rabbits. Within one week the luminal surface of the grafts with fibril length of 30, 60 and 90μm was completely covered by a clot layer, which was associated with a clot mass filling up their internodal space. On the other hand, the luminal surface of the grafts with fibril length of 15μm was only rarely covered by a thin clot layer, and their internodal space was often empty. Complete neointimal healing with higher degree of endothelial coverage was attained by 3 months in the grafts with fibril lengths of 30μm or longer, while the 15-μm fibril-length grafts were not healed even at one-year after implantation. Although intimal thickening was brought about with enlargement of fibril length, one-year patency leas the highest in the grafts with fibril length of 90μm. These results suggest that enlarged fibril length of EPTFE grafts is effective in luminal clot-layer formation and subsequent intimal healing of the grafts, ensuring superior graft patency.
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M. ANDO, S. ADACHI, M. NAKAYA, Y. KAWASHIMA
1993 Volume 22 Issue 2 Pages
455-458
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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A gelatin impregnated dacron prosthesis (Gelseal) was implanted in 92 patients with thoracic aortic aneurysms. Types of aneurysms were aortic dissection in 29 patients and nondissected aneurysms in 63 patients. We used cardiopulmonary bypass in 60 patients and centrifugal pump in 32 patients as an adjunct in operation. Operative procedure was graft replacement of ascending aorta in 14, total arch in 32, partial arch in 12, descending aorta in 23 and thoracoabdominal aorta in 11 patients respectively. 13 cases of respiratory failure, 7 of low cardiac output syndrome, 6 of acute renal failure, 5 of hemorrhage necessitating reexploration and 5 of cardiac tamponade were encountered as postoperative complications. There were 8 hospital deaths. Neither were considered due to the use of Gelseal graft. Gelseal graft was very easy to perform the anastomosis and no bleeding was observed at the site of anastomosis and the graft itself in the case of cardiopulmonary bypass. We noticed high fever in 29 patients in one and two weeks after surgery. This fever was mainly considered because of the reaction against gelatin. We concluded that the clinical use of Gelseal graft is useful for the graft replacement of thoracic aorta.
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S. SHINDA, Y. TADA, O. SATO, A. OSHIMA, T. HURUYA, Y. IDEZUKI
1993 Volume 22 Issue 2 Pages
459-461
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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A sequential study of an endothelial cell (EC)-seeded graft was performed. Canine vascular ECs were harvested enzymatically and seeded onto an ultrafine polyester fiber graft, which was implanted into a carotid artery of the identical dog thereafter. These grafts were explanted two weeks and three months later, and a histological examination of the midportion and the anastomotic site was carried out. The EC monolayer was demonstrated in the midportion in both time period, but more smooth intimal surface and the multilayer-formation of subendothelial tissue were observed at three months. On the other hand, the continuous subendothelial thickening was shown at the anastomotic sites with time. These observations suggest that the specific reaction at the anastomotic sites of the EC-seeded grafts should be clarified for achieving better long-term patency rate.
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S NIU, H KURUMATANI, S SATOH, K KANDA, T OKA, K WATANABE, T KUNITOMO
1993 Volume 22 Issue 2 Pages
462-467
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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This study aims at developing novel vascular prostheses with a small caliber based upon the following hypothesis: biodegradable matrices that are to be absorbed into growing neointima might prevent intimal hyperplasia at the anastomotic site. Characteristics of the graft are as follows: (1) ultrafine polyester fibers were used for structural framework, and (2) two kinds of protein were used for biodegradable matrices; one is cross-linked gelatin-heparin complex for “artificial intima”, and the other heatdenatured albumin for “artificial matrix” as a presealant of the graft interstices. Six grafts, 3 mm in diameter and 4 cm long, were segmentally replaced in the carotid arteries of three mongrel dogs (mean BW 11.3kg). Five of six grafts were patent (83%) and had no thrombus macroscopically four weeks after surgery. Histological examinations revealed that neither hyperplasia nor detachment of the gelatin layer was observed in the neointima that advanced onto the luminal surface at the anastomotic site, and that the artificial matrix was converting into fibrous tissue. Scanning electron microscopy demonstrated that no fibrin layer was formed on the artificial intima in the middle of the graft. These results suggested that the artificial intima was excellent substructure for neointima and remained antithrombogenic, and that the artificial matrix had no adverse effect on the surrounding tissue. Our concept might contribute to the successful development of vascular prostheses with a small caliber.
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H MIWA, T MATSUDA, K KANDA
1993 Volume 22 Issue 2 Pages
468-472
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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The hierarchically structured hybrid vascular graft, resembling to the layered structure of the intima and the media of a natural vessel, was considered to provide the structural stability and antithrombogenicity especially at an acute phase. Two types of hybrid vascular grafts were constructed on knitted Dacron grafts (ID=4mm, Length; 6cm) in vitro. One consisted of endothelial cell monolayer and smooth muscle cell multilayers (MODEL II), the other consisted of only endothelial cell monolayer (MODEL I). Designed artificial basement membrane and extracellular matrix were a mixed gel of type I collagen and dermatan sulfate. Both types of grafts were implanted in nine dogs for up to 12 weeks. All grafts were patent. At 2 weeks post implantation, MODEL II-grafts showed the oriented intima completely covered with endothelial cells, and compactly reorganized media composed of multilayered smooth muscle cells, while MODEL I-grafts showed non-oriented endothelial cell monolayer and few smooth muscle cells beneath the endothelium. Observation up to 12 weeks showed the tendency for the thickness of media to increase time-dependently. At 2 weeks post implantation, more complete endothelial coverage was observed in MODEL II-grafts than MODEL I-grafts (100%vs 92%). It can be said that in vitro constructed smooth muscle cell layer contributes to the stabilization of endothelial layer at an acute phase.
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H MIWA, T MATSYDA, N TANI
1993 Volume 22 Issue 2 Pages
473-477
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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A newly devised hybrid vascular graft was developed, into which design concepts of biomechanical compatibility and antithrombogenicity were incorporated. The graft consisted of three components, polyurethane tube (ID=3mm, Length; 5cm), complex gel of type I collagen and dermatan sulfate as artificial basement membrane (ABM), and in vitro constructed endothelial cell (EC) layer. Eighteen grafts were implanted bilaterally into the carotid arteries of nine dogs for up to 26 weeks. The patent grafts showed the high degree of endothelialization more than 90%. This result was explained by the biologic activities of the ABM, such as enhanced adhesion and growth of ECs, reduced adhesion of platelets and a high resistance to the shear stress. A little hyperplasia at the anastomotic site was observed after 12 weeks of implantation. The synergistic activity of a compliant vascular graft and ECs might lead this good result.
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K KANDA, T MATSUDA, T OKA
1993 Volume 22 Issue 2 Pages
478-482
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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Incorporation of the hierarchical structure made of orientated cells into a hybrid vascular prosthesis might enable us to build a more vital and functional graft. Along with this hypothesis, we attempted to organize the smooth muscle cell layer with regulated orientation in vitro. A “hybrid artificial media” was prepared with inoculation of arterial smooth muscle cells (SMCs) derived from bovine aorta into Type I collagen gel in which a silicone tube was embedded. Subsequently, the “hybrid artificial media” was subjected to the mechanical stimulation, resembling a pulsatile stress in vivo, which was induced by periodic ballooning of the silicone tube with an amplitude of 5% in diameter and a frequency of 60 times per minute. In stress-loaded gels, bipolar spindle-shaped SMCs and collagen fiber bundles exhibited coaxial orientation around the tubes which proceeded time-dependently, while, in non-stressed gels, polygonal-shaped SMCs and collagen fiber networks showed random orientation. The mechanical stress-loaded “hybrid artificial media” constructed a highly-ordered structure similar to the media of native muscular arteries.
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K KANDA, T MATSUDA, T OKA
1993 Volume 22 Issue 2 Pages
483-487
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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Cells in living tissue align to form the most efficient configuration for functioning. Vascular cells of arterial walls are continuously subjected to the periodic stretch induced by a pulsatile flow, which might affect the cellular orientation. In this study, endothelial cells (ECs), smooth muscle cells (SMCs) and fibroblast cells (FCs) derived from bovine aorta were cultured on the elastic translucent films made of polyurethane, which were subsequently stretched with variable amplitudes ranging from 5% to 20% and frequencies from 15 to 120 RPM for up to 24 hours. The time-lapse video-recorded views of phase contrast microscope were analyzed by a computerized image processor in order to quantitatively evaluate the cellular orientational response and morphological changes. The cells on the stress-loaded films aligned perpendicularly to the direction of stretch, while those on the stationary ones remained in random orientation. The orientation response proceeded with time, and was more pronounced with higher amplitudes or frequencies of the stresses. The response of SMCs and FCs advanced significantly more rapidly than that of ECs. Little morphological changes were observed, irrespective of stress-loading or nonloading. These mechanically induced orientation response of vascular cells might provide us a fundamental basis on the regulation of cellular orientation in vitro.
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Tetsuya ARIYASU, Koichi TAMURA, Yasuhiko SHIMIZU, [in Japanese], Yoshi ...
1993 Volume 22 Issue 2 Pages
488-494
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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We've tried microporous, compliant, slow biodegradable vascular grafts made of polyurethane for replacement of small caliber carotid arteries of the thirty mongrel dogs. The diameter were 2.5-3mm and replacement ware 20mm long. Four kinds of vascular grafts of various compliance were tried (three ether types and one ester type). The obsevation periods were from two days to ninety four days. Every graft were got after sacrifice or death. Only ester type grafts were patent and the other ether types were all failed. One ether type ruptured and two other ether type failed for thrombi. We show here the healing process of the patent grafts and the difference of compliances among the four grafts. We conclude that aomong the biocompatibility compliance is very important and the compliance should be adjusted to pulsatile synchronously to host arteries.
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T OKOSHI, G SOLDANI, M GODDARD, PM GGLLETTI
1993 Volume 22 Issue 2 Pages
495-499
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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Two types of spongy polyurethane-polydimethylsiloxane (Cardiothane 51
TM, Kontron Instruments, Inc., U.S.A.) vascular grafts (PUG) with an internal diameter of 1.5mm were fabricated by a spray, phase-inversion technique: PUG with hydraulic permeability (HP) of 2.7ml/min/cm
2 (PUG-2.7) and PUG with HP of 39ml/min/cm
2 (PUG-39). Twenty three straight PUG-2.7, 17 straight PUG-39 (1.5-2.0cm in length) and one loop PUG-39 (10cm in length) were implanted by the same surgeon end-to-end in the infrarenal aorta of 41 male Sprague-Dawley rats. Patency of PUG-2.7 was 73% (8/11) at 2 weeks, but, at 3 months, decreased to 8% (1/12). At 3 months post-implantation patency of the straight PUG-39 was 76% (13/17) and the loop PUG-39 was also patent. The sole patent PUG-2.7 showed neointimal hyperplasia and incomplete endothelialization. All but one of the patent straight PUG-39 showed a glistening and transparent neointima with complete endothelialization and no anastomotic hyperplasia. The loop PUG-39 displayed endothelialization from each anastomosis and in many islands in the middle portion of the graft. Thus, PUG with a higher HP showed better patency and healing in the rat aortic replacement model.
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Y MISAWA, T HASEGAWA, Y SOHARA, Y KAMISAWA, N HASEGAWA, T ARAI
1993 Volume 22 Issue 2 Pages
500-502
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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Polyurethane vascular prostheses (Thoratec Laboratories Corporation, USA) are compliant grafts. The grafts with 6mm diameters and 2cm lengths were implanted in the abdominal aorta of ten mongrel dogs. At operation heparin sodium was administered at the rate of 2mg/body weight (Kg), but after operation no other agent like anticoagulant was taken. Three to ten weeks after the implantation, these grafts were easily removed. All grafts were patent. Samples of extracted grafts were submitted for scanning electron micrographic and routine microscopic examinations. Spindle-shaped endothelial cells were observed all over the grafts. Beneath the layer, there were some fibrous tissue near the anastomoses, and a few fine elastic fibers could be observed within these connective tissue. In conclusion, polyurethane vascular prostheses could be available for vascular reconstruction.
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Y ICHIKAWA, Y NOISHIKI, T KOSUGE, M ISHII, H KAJIWARA, K YAMAMOTO, K I ...
1993 Volume 22 Issue 2 Pages
503-506
Published: April 15, 1993
Released on J-STAGE: October 07, 2011
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A biological RV-PA extracardiac conduit was developed using a bovine jugular vein with a natural valve and was evaluated in the animal study. Bovine jugular vein had softness, pliability peculiar to venous tissue and had ideal form as a natural valve in hemodynamics. To maintain these physical properties and form the vein was cross-linked with a glycerol polyglycidyl ether polyepoxy compound (PC). The conduits were implanted into RV-PA position of six dogs. The main PA was ligated after implantation. Postoperative catheterization and X ray RV graphy were done at four hours and 20 days after implantation. RV-PA pressure gradients by catheterization were trivial and revealed that the conduits were patent without major kinking. There were no serious thrombi on the conduits but there were a small amount of thrombi in the pockets and on the anastomotic line of the fabric. These results indicated that the newly developed conduit has a special physical properties whith were not seen in any conduit used in clinic.
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