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[in Japanese]
1995 Volume 24 Issue 1 Pages
1
Published: February 15, 1995
Released on J-STAGE: October 07, 2011
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[in Japanese], [in Japanese], K NISHIHARA, [in Japanese], [in Japanese ...
1995 Volume 24 Issue 1 Pages
3-17
Published: February 15, 1995
Released on J-STAGE: October 07, 2011
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Y. SAKAI, K. NARUSE, I. NAGASHIMA, T. MUTO, M. SUZUKI
1995 Volume 24 Issue 1 Pages
18-23
Published: February 15, 1995
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Approximately a 1/4 cell number of porcine hepatocytes needed for a bioartificial liver for a pig (10-15kg) with liver failure was successfully re-organized to spheroids within 24 hours by 1-L scale suspension culture vessel fitted oxigen supply apparatus. Although the cell number was gradually decreased in subsequent continuous suspension culture of the spheroids during 10 days, the functional expressions per cell of the spheroids were 3-5 times higher as compared to those of monolayers. Collagen gel entrapment of the spheroids lowered the functional expressions. No deteriolation was observed in the function of the spheroids in suspension culture even in direct contact with 100% porcine or human plasma.
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M. SAWA, S. KASAI, Y. KINO, M. MITO
1995 Volume 24 Issue 1 Pages
24-27
Published: February 15, 1995
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A hybrid artificial liver using isolated hepatocytes requires methods for a large scale isolation and long-term preservation of viable hepatocytes with well maintained cellular functions and a suitable module, which provides selective permeability of molecules and prevents immunologic reactions, should be developed. We found that plasma perfusion of D-gal inducedhepatic failure dogs with a hybrid artificial liver using dog hepatocytes could prolong their survival time. Cryopreservation of isolated dog hepatocytes using Me2SO as a cryoprotectantshowed 75% of post thaw viability. Cellulose multiporous microcarriers have been investigated for the maintenance of hepatocellular functions and we found better NH3 and fructose metabolism in hepatocytes attached to the microcarriers than in monolayer cultured hepatocytes. However, the metabolic activity of hepatocytes attached to the microcarriers in a extracapillary space of a capillary type hollow fiber module was lower than those in a culture dish. A new hollow fiber module with larger extracapillary space will be investigated of its availability for long-term culture of hepatocytes attached to the microcarriers.
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Tsuyoshi KAWAMURA
1995 Volume 24 Issue 1 Pages
28-29
Published: February 15, 1995
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M KITAMURA, T AKIMOTO, T KOYANAGI, H NISHIDA, M ENDO, A HASHIMOTO, H K ...
1995 Volume 24 Issue 1 Pages
30-32
Published: February 15, 1995
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The purpose of this investigation was to assess possibility for implantation of the internal thoracic artery (ITA) homograft as a new small diameter vascular substitute in cardiovascular surgery. Left subclavian artery to left atrial appendage shunts with fresh ITA homografts (n=6) or ITA autografts (n=5) were made by modified techniques of coronary artery bypass grafting in mongrel dogs (body weight: 11-16.5kg). All dogs received neither anticoagulant nor immunosuppressive therapy. Inner diameter of the ITA grafts was between 1.4 and 2.0mm. Blood flow of ITA grafts was measured by electromagnetic flowmeters. The graft flow was 6-14ml/min before harvest and 67-220ml/min just after implantation, and there was no significant difference between both groups. Flow of the ITA homografts decreased significantly compared with ITA autografts one month after operation, but 5 of 6 ITA homografts were patent. Histopathological findings of the grafts showed vascular rejection in the homograft group. In conclusion, ITA homograft with some immunomodulation might be a new small diameter vascular substitute for specific procedures in cardiovascular surgery.
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Y NAKAYAMA, T MATSUDA
1995 Volume 24 Issue 1 Pages
33-37
Published: February 15, 1995
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This paper presents a newly designed
in vitro model which permits a quantitative analysis of endothelial cell ingrowth and tissue formation on microporous segmented polyurethane films. The micropores, of which pore sizes ranged from 7mm to 100mm in diameter were precisely created on the films with irradiation of a KrF excimer laser (248nm) through a photo-mask. Cell ingrowth from one face of the micropored films, in which an endothelial cell monolayer sheet was prepared, to the cell-free opposite face through micropores was quantitatively examined with scanning electron microscopy. A circular cellular sheet initiated from the micropore was being expanded due to migration and proliferation of cells as the incubation period proceeded. The cell population was gradually reduced in the vicinity of the leading edge. An average migration distance of cells increased with an increase of pore size. A computer-aided automatic sample movement enabled to prepare multiple-holes distributed in a film as designed. In microporous films with different sizes and populations of micropores, in which the total pore area per unit area was set for 1/100, both highest cell ingrowth rate and endothelialization rate were observed on the pore sizes of a few tenths to several tenths of microns. This model would be useful as an
in vitro model which simulates the tissue ingrowth through micropores and resultant tissue formation process.
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M. TAKATSUKA, Y. LEE, K. ISHIBASHI, T. SUGAWARA, T. MATSUDA
1995 Volume 24 Issue 1 Pages
38-41
Published: February 15, 1995
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Cell adhesive peptide containing RGD (Arg-Gly-Asp) tripeptidyl sequence and gelatin were derivatized with photoreactive phenylazido group. The coating of these photoreactive artificial extracellular matrices (ECMs) and subsequent ultraviolet (UV) irradiation resulted in its surface chemical fixation. Surface photochemical treatment of these materials on hydrophilic polymers produced a cell-adhesive surface region where UV light was irradiated. The luminal surface modification of segmented polyurethane-based artificial grafts with these materials markedly facilitated adhesion and proliferation of canine endothelial cells (ECs), producing hybrid grafts. The study of implantation for up to two weeks suggested that, irrespective of type of photoreactive artificial ECM, an EC monolayer formed in vitro is quite stable in vivo probably due to chemical fixation of ECMs on substrate surfaces.
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Hikaru TAIRA, Kazunori KATAOKA, Teiji TSURUTA, Masao HAYASHI
1995 Volume 24 Issue 1 Pages
42-47
Published: February 15, 1995
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Substrata derivatized with amino groups are promising for the primary culture of endothelial cells. To clarify the mechanism of endothelial cell adhesion to amine-denvatived substrata, we have quantified adsorption of bovine plasma fibronectin (FN), bovine plasma vitronectin (VN) from fetal calf serum (FCS) by enzyme linked immunosorbent assay (ELISA) on polystyrene derivatives having different content of polyamine side chain with repeating array of diamine. Adsorption of FN, VN from FCS were increased with increasing diamine content in copolymer. Then, we have evaluated Vroman effect of FN, VN. Adsorption of FN was decreased with time, but this tendency was inhibited with increasing diamine content in the copolymer. It was suggested that diamine in copolymer enhanced interaction between this copolymer and FN. We have evaluated adhesion and spreading behavior of bovine aortic endothelial cell (BAEC) on the surfaces adsorbed with FCS at varying precoating time. It was demonstrated that adsorbed FN from FCS on the copolymer might facilitate BAEC adhesion, whereas VN might facilitate BAEC spreading.
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S. NAGAOKA, H. KAWAKAMI
1995 Volume 24 Issue 1 Pages
48-51
Published: February 15, 1995
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The adhesion of pathogenesis bacterial cells (
E. coli and
S. aureus) onto the surface of H-PSD were demonstrated. Qualitative and quantitative evaluations showed that a large number of bacterial adhesion and biofilm formations were found on the surface of PVC, whereas significant reductions in the bacterial adhesion and no biofilm formations were observed on H-PSD. These results suggest that the hydrophilic surface of H-PSD plays an important role in the bacterial repellence by reduction of the hydrophobic interaction between bacteria and substrate, and immobilized heparin, which does not have bactericidal activity but is the strongest naturally occurring organic acid in the body, should enhance the effect by the electrostatic repulsive force against negatively charged bacterial cell membrane. Plasma protein adsorbed on the polymer films exerted influence on bacterial adhesion by the biospecific interactions.
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K. ABE, K. SUZUKI, T. OKANO, Y. SAKURAI, T. HORIE
1995 Volume 24 Issue 1 Pages
52-58
Published: February 15, 1995
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An ultrastructural preservation of platelet plasma membrane glycocalyx (GC) which adhered on HEMA-St ABA type block copolymer (HSB) surfaces for 5 hours was analyzed by transmission electron microscopy (TEM). The platelet GC was stained with ruthenium red. Then, the ultrastructural changes observed by TEM of ultrathin vertical sections of the adhered platelets were evaluated quantitatively using a highspeed image processor-analyzer. PSt and HEMA-St random copolymer surfaces were used as controls. The platelets on the HSB surfaces adhered with supporting narrow spaces which formed scaffolding, keeping the GC the same as the intact platelet GC. On the other hand, the platelets on the control surfaces adhered without the narrow spaces for the GC, indicating strong adhesion. Their external GC seemed to be lacking in some places. The intracellular changes of platelets on the HSB surfaces were significantly inhibited compared to those on the control surfaces. The number of the platelet storage granules of the HSB surfaces showed no significant difference compared to intact platelets. These results suggest that remarkable inhibition of the platelet ultrastructural changes on the HSB surfaces is due to good preservation of ultrastructure of the platelet GC followed by the continued soft landings of the platelets for 5 hours.
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S. KURODA, C. NOJIRI, T. KIDO, K. SENSHU, H. NAGAI, K. SAKAI
1995 Volume 24 Issue 1 Pages
59-64
Published: February 15, 1995
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We have evaluated blood compatibility of six different segmented polyurethanes (PUs) including five polyether-PUs and one polyurethane-urea (PUU) having PTMG as a soft segment, using our epifluorescent video microscopy (EVM) combined with a parallel plate flow cell. HEMA/Styrene block copolymer (HEMA/St), which we have already proven to be an excellent nonthrombogen is polymer over existing PUs, was used as a control. EVM system measured the amount of adhered platelet on the surfaces under the flow of human whole blood containing mepacrine labelled platelets perfused at a wall shear rate of 200/sec every one minute intervals for 20min. Platelet activation (β-TG) and complement activation (C3a) were also measured. PUU showed significantly higher platelet adhesional behavior than the other PUs. On the other hand, PU-PTMG (MW 1500) showed lowest platelet adhesional behavior among six PUs, which was comparable to HEMA/St. β-TG level of each polymer was somewhat related to platelet adhesional tendency. Complement activation was inversely correlated with the results of platelet adhesion and activation potentials except HEMA/St, which showed least platelet activation and complement activation. From the chemical compositions, we could divide these PUs into three categories: 1) PUU, 2) PU with lower MW of PTMG, 3) PU with higher MW of PTMG. From our experimental results, we could confirm that these PUs were divided into three categories above mentioned, i. e., 1) PU with higher MW of PTMG showed lesser platelet adhesion and higher complement activation than PU with lower MW of PTMG, 2) PUU showed the highest platelet adhesion. Thus, blood compatibility of PUs were much influenced by their chemical compositions.
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H. KAWAKAMI, S. NAGAOKA
1995 Volume 24 Issue 1 Pages
65-71
Published: February 15, 1995
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Aromatic polyimides derived from 2, 2'-bis (3, 4-dicarboxy-phenyl) hexafluoropropane dianhydride (6FDA) and 3, 3'- or 4, 4'-diaminodiphenylsulfone (m-DDS or p-DDS) were synthesized to develop a novel membrane for oxygenator. An asymmetric gas membrane prepared by dry/wet phase inversion process consisted of ultrathin, selective and defect-free skin layer and of porous substructure. CO
2 transport increased with a decrease in CO
2 pressure and obeyed dual-mode transport mode described by a combination of Henry's mode and Langmuir mode. CO
2 removal from the membrane was significantly larger than presently available polymers for membrane oxygenators, polydimethylsiloxiane (PDMS) and polypropylene (PP). Amount of platelets adhered on the polyimide membranes was lower than those of PDMS and PP and the deformation or aggregation of platelets on the surface of polyimide was not observed.
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K. MIYAMOTO, T. NAKAMURA, Y. SHIMONISHI, M. TOKITA, T. KOMAI, M. YONEK ...
1995 Volume 24 Issue 1 Pages
70-73
Published: February 15, 1995
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The cryogel obtained from the patient with rheumatoid arthritis composes of fibronectin (FN), fibrinogen and heparin. In addition, a large quantity of EDA (+) FN, one of the cellular FN, was included. In order to identify the mechanism of cryogel formation, we attempt to determine the hydrodynamic radius (Rh) of the aggregates consist of FN and heparin by dynamic light scattering method using DLS-700 (Otsuka electronics, JPN) with Argon-ion laser (488nm) as the light source. We found that the Rh of EDA (+) FN increase with addition of heparin, in contrast to the fact that plasma FN do not aggregate with heparin. We also found that the Rh of the EDA (+) FN and heparin aggregates is hundred times larger than that of plasma FN at body temperature region and ten times at lower temperature region. Thus we conclude that the EDA (+) FN is the nucleus materials for the cryogel formation and cooling of the plasma makes the cryofiltration effective and easier.
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Y NAKAYAMA, T MATSUDA
1995 Volume 24 Issue 1 Pages
74-78
Published: February 15, 1995
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This paper presents a new method to provide a durable layering of hydrogels on a substrate surface by an excimer laser ablation in which photolyzed reactive materials are ejected away. The procedure is as follows. At first, a three layered (A-B-A type) polymer film was prepared, where A is polyethylene (PE) which has an extremely small absorption coefficient at the laser wavelength and B is poly (N, N-dimethyl-acrylamide) (PDAAm) which has a large one. The layered film was subjected to irradiation of ArF excimer laser pulses (193nm, 30-70mJ/cm
2 pulse) and to subsequent washing with water. The treated PE surface exhibited a hydrogel-like nature upon immersion into water. No delamination occurred even upon vigorous washing with water. ESCA analysis showed that the surface chemical composition of the treated PE was closed to that of PDAAm, suggested that non-wettable PE was covalently bonded with wettable PDAAm. The thickness of the gel increased with an increase in laser energy density per pulse and the accumulation of pulses. Significant inhibition of platelets adhesion was observed
in vitro on hydrogelated surfaces. Heparin was immobilized in a hydrogelated surface and chemically fixed on a substrate surface by this method.
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K. ABE, K. SUZUKI, T. OKANO, Y. SAKURAI, T. HORIE
1995 Volume 24 Issue 1 Pages
79-84
Published: February 15, 1995
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The ultrastructural changes observed by transmission electron microscopy (TEM) of ultrathin vertical sections of platelets adhered to HEMA-St ABA type block copolymer (HSB) surfaces for 10 hours at room temperature were evaluated quantitatively using a high-speed image processor-analyzer (IA). PSt and HEMA-St random copolymer surfaces were prepared as controls. The interaction between the platelets and the polymer surfaces was carried out by the microsphere column method. The four parameters (Area, Breadth, Roundness and Number of storage granules per 1μm
2) for the TEM images were measured by the IA, followed by statistic tests. The ultrastructural changes of the platelets of the HSB surfaces were significantly inhibited statistically compared to those of the control surfaces. The number of the platelet storage granules of the HSB surfaces didn't indicate any significant difference compared to that of the intact platelets. The narrow spaces thought to be of platelet membrane glycocalyx were then observed between the platelet membranes and the HSB surfaces. These results suggest that the HSB surfaces inhibit remarkably the platelet ultrastructural changes due to the continued soft landings of platelets for 10 hours.
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Mu Nam KIM, Takato NAKAMURA, Keiichi MIYAMOTO, Masayuki TOKITA, Takash ...
1995 Volume 24 Issue 1 Pages
85-91
Published: February 15, 1995
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Preparation of Biointerfacial Materials Derived from Gelatin with High Melting Point. We prepare amphiphilic agent consist of acylated gelatin to improve the adhesion of cell or tissue with artificial materials. Variously substituted hexanoyl, decanoyl, and myristoil gellatin are prepared using the corresponding carboxylic acid active ester in aqueous media at low temperature. We find that these acylated gelatins thus prepared are one of a thermoreversible gel forming materials and the melting temperatures of the acylated gelatin gels are rather lower than that of original gelatin gels except for myristoil derivatives. The melting points of myristoylated gelatin (27.5% of amino group are substituted) gel (16%) is 52.5°C that suggests the cross linking regions of the acylated gelatin gel may be stabilized by the hydrophobic interactions between acyl groups. 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 entirely hydrophilic properties of the mostly outer layer of the gel surfaces are noted. These results indicate that the myristoilation of gelatin causes the preferable changes to the gelatin gel as a biointerfacial agent for hybridized artificialgrafts.
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M. TERAMACHI, H. SAKAKIBARA, T. KIYOTANI, Y. TAKIMOTO, N. OKUMURA, T. ...
1995 Volume 24 Issue 1 Pages
92-96
Published: February 15, 1995
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In order to develop an ideal topical hemostatic agent, we manufactured two types of cotton-like fibrous hemostat which were made from alkali-solubilized collagen and cross-linked in the following two ways; 1) heat dehydration cross-linking at 130°C for 6h (the heated hemostat), or 2) heat dehydration cross-linking at 140°C for 5h followed by gamma irradiation at 25kGy (the irradiated hemostat). We evaluated the hemostatic efficacies and tissue reactions of these two hemostats in comparison with a commercially available collagen hemostat (Avitene®) and a previously reported cotton-like fibrous hemostat made from enzyme-solubilized collagen (the enzyme hemostat). It was found that the hemostatic efficacy of the irradiated hemostat was comparable to that of the enzyme hemostat and superior to Avitene®. The histological study revealed that the irradiated hemostat induced a milder inflammatory reaction than Avitene®, and that its collagen was almost completely absorbed within 3 weeks. These findings suggest that cotton-like fibrous hemostats made from alkali-solubilized collagen have potential for clinical use.
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K ISHIBASHI, Y NAKAYAMA, K KAWAZOE, T MATSUDA
1995 Volume 24 Issue 1 Pages
97-101
Published: February 15, 1995
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We developed a novel hemostatic agent composing benzophenone-derivatized photocurable gelatin and poly (ethylene glycol) diacrylate as active ingredients, which were dissolved in a phosphate buffer solution. We studied the hemostatic efficacy of the photocurable gelatin on rat liver, in which incisions were made with a knife in an laparotomy, and evaluated the usefulness as an hemostatic agent in a laparoscopic surgery. Excimer laser light (KrF; 248nm) through a UV-fiber was irradiated on the damaged liver tissues which were pre-coated with the hemostatic agent. The viscous solution was converted to a hydrogel within several tenth seconds of irradiation, and concomitantly hemostasis was completed. At seven days after surgery, little photocurable gelatin remained in the liver wound, and scarring, infiltration of inflammatory cells and little necrotic sign in the surrounding tissue were noticed on histological examination. In the laparoscopic surgery, the in situ gelation of the hemostatic agent on the liver surface was realized by the use of the newly designed fiberscope, by which delivery of hemostatic agent and transmission of eximer laser light were carried out. These results suggest that the photocurable hemostatic agent developed here is very useful in the in situ gelation by excimer laser irradiation through the fiberscope, which may provide a great potential for thoracoscopic and laparoscopic surgeries.
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Y NAKAYAMA, K ISHIBASHI, T MATSUDA
1995 Volume 24 Issue 1 Pages
102-105
Published: February 15, 1995
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Photocrosslinkable gelatin having photoreactive benzophenone group was prepared by condensation reaction of gelatin with 4-benzoyl benzoic acid using a water-soluble carbodiimide. Irradiation of KrF excimer laser pulses (248nm, 50Hz) to 20wt% buffer solution of the photocrosslinkable gelatin produced a gel within a few seconds. An increase in laser energy density per pulse and the accumulation of pulses resulted in an increase in gel yield. Regardless of gel yield, resultant gels were highly swellable. When polyethylene glycol) diacrylate (Mw=4000) as a co-crosslinker was mixed with the modified gelatin, the equilibrium degree of swelling in water was reduced in dose-dependent manner. A rat liver incised with a knife in laparotomy was coated with a mixed buffer solution of the modified gelatin and the co-crosslinker. Then excimer laser pulses were irradiated on the treated liver. The viscous solution was immediately converted to a hydrogel and concomitantly hemostasis was completed. Histological examination showed that, at seven days after surgery, little photocrosslinked gelatin was left in the liver wound. These results suggest that the photocrosslinkable gelatin developed here may be used as a biodegradable hemostatic glue in laparoscopic surgery with an aide of excimer laser irradiation.
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K. MATSUDA, T. BAN, S. KITAMURA, A. YAMASATO, T. TAKEUCHI, T. ODA
1995 Volume 24 Issue 1 Pages
106-110
Published: February 15, 1995
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GRF glue consists of mixture of gelatin and resorcin. The mixture is hardened by the addition of medical formalin. We used this glue for hemostasis and adhesive during cardiac and vascular surgery and studied their usefullness, safety and efficacy. For hemostsis, we used the glue in 10 patients(coronary artery bypass grsfting in 5, valve replacement in 3, and replacement of abdominal aortic aneurysm in 2). For adhesive, we performed reconstruction of aortic stumps of dissecting aortic aneurysm using the glue. During opeation we examined adhesive and hemostatic effect, and ease of handling. After operation we performed biochemical, immunological, hematological analysis. As a result, we concluded that GRF glue was usefull and efficient for hemostasis and adhesive.
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T. KIYOTANI, Y. OTANI, Y. TABATA, Y. IKADA, Y. KITAGAWA, T. NAKAMURA, ...
1995 Volume 24 Issue 1 Pages
111-114
Published: February 15, 1995
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The hemostatic effectiveness of a newly synthesized biological adhesive was studied in comparison with fibrin glue in animal experiments. In six dogs, the spleen was punctured with an 18-23G needle. One minute after puncture, the new gelatin glue and fibrin glue were applied for hemostasis at the site of sporadic or continuous, but not massive, bleeding. The bleeding was measured every 30s for up to 7min. The glue was then removed to examine whether or not rebleeding would occur. Our new glue was found to be superior to the fibrin glue with respect to sequential bleeding, total amount of bleeding, hemostatic success rate, and rebleeding rate after glue removal. We conclude that the new glue has hemostatic effectiveness superior to that of fibrin glue.
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T. KIYOTANI, Y. KITAGAWA, M. TERAMACHI, Y. TAKIMOTO, T. NAKAMURA, Y. S ...
1995 Volume 24 Issue 1 Pages
115-119
Published: February 15, 1995
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Amnion is very useful as a source of human collagen. We made an amnion-PGA (polyglycolic acid) seat and evaluated its efficacy for pledgets and dressing materials in animal experiments. In a total of 50 dogs, amnion was used in pledgets for suturing of lung, trachea, heart, liver, spleen and pancreas, and as a dressing material for the cut surface of the liver. The results showed that the amnion-FGA seat was useful for suture support and for prevention of bile leakage from liver tissues. We conclude that the amnion-PGA seat is useful as a supporting material for sutures and as a dressing material.
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I. MASASHI, S. TADAHIRO, G. KAZUTOMO, I. YUHICHI, Y. HIROKI, O. NORIFU ...
1995 Volume 24 Issue 1 Pages
120-124
Published: February 15, 1995
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We studied the antithrombogenicity, patency and healing chracteristics of PFIV. Eleven PFIVs were implanted in dog abdominal aorta. Seven of 8 PFIVs (87%) were patent at the time of sacrifice. At 1 month after implantation, the configuration of anastomotic site was smooth and there was little thrombus. In histological study, intimal thickness was about 50μm and endothelioid cells were seen in the anastomotic region. However, about 100μm thick fibrin remained in the midportion of PFIV. At 3 months after implantaion, the endothelial cells covered the inner surface of PFIV completely. The basic graft material without fibrin matrix, preclotted with blood, showed a similar healing at 2 months after implantation. We consider both plasmin-treated fibrin matrix and high porous property contribute to this good healing of PFIV.
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M NAKAMURA, T KAZUI, T WATANABE, Y KURIMOTO, T TANAKA, O YAMADA, S. KO ...
1995 Volume 24 Issue 1 Pages
125-128
Published: February 15, 1995
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Between November 1992 and April 1994, two types of woven Dacron grafts presealed with collagen were implanted into the thoracic aorta in sixty-five patients. We evaluated the clinical effectiveness of woven Dacron grafts, forty-five with collagen impregnation (Hemashield: HS) and six with external collagen coating (Hemaguard: HG). There was no difference in inflammatory reactions between two groups. There was difference in the quantity of postoperative discharge between HS group and HG group. There was no difficulty in anastomosing because the grafts were very soft. There was no complication caused by hemorrhage, and was no difference in the quantity of bleeding. Computer tomography showed no late graft complication-specially, no dilatation. These grafts was useful for replacement of the thoracic aorta.
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M KUWABARA, T ONITSUKA, K NAKAMURA, K ARAKI, M YANO, Y KOGA
1995 Volume 24 Issue 1 Pages
129-131
Published: February 15, 1995
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Gelatin sealed knitted dacron grafts (Gelseal) and collagen shield woven dacron grafts (Hemashield) were implanted into thoracic and abdominal aorta in 22 patients. There were 12 men and 10 women with 58.8 years of mean age. Effect of coated grafts on the inflammatory response were evaluated. The value of CRP, body temperature and WBC count in coated group were not significantly higher than that in uncoated group. However, the total positive rate of inflammatory response were 50% of Gelseal group and 36% of Hemashield group. In conclusion, coated grafts would be implanted only into emergent cases and patients operated under cardiopulmonary bypass.
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-WOVEN DACRON VERSUS KNITTED DACRON-
S. FUNAKI, T. KAWADA, K. KIKUCHI, K. NISHIMURA, S. ENDO, T. KOYAMA, S. ...
1995 Volume 24 Issue 1 Pages
132-134
Published: February 15, 1995
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Replacement of the thoracic or abdominal aorta was performed by the two different prosthetic grafts in 45 patients. Gelatin impregnated knitted Dacron graft was used in 17 cases, and woven Dacron in 28 cases. The interval change in size of the implanted grafts was serialy measured by CT scanning after surgery. Gelatin impregnated kinitted Dacron graft dilated significantly in diameter within a month after operation (31.3±8.6% vs 5.2±8.3% P<0.001). Although the average, follow-up period was short, further graft dilation was not observed at least within 24.5 months. No complication related to the graft has been observed, but careful follow-up is necessary.
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M KATO, M KANEKO, T UEDA, D KISHI, Y YOSHII, M HIRAMATSU, ADACHI S
1995 Volume 24 Issue 1 Pages
135-138
Published: February 15, 1995
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We report a new surgical method for repairing aneurysm of the transverse arch and descending aorta using stentreinforced grafts. In this method, the force of the stent pressing the graft toward the vascular wall substitutes for the distal anastomoses of brachiocephalic vessels and descending aorta. This surgery can be performed through only a median sternotomy with minimal circulatory arrest time. We applied this new method in a patient with an enlarged type B dissection. This method offers a less invasive surgical procedure especially for high-risk patients.
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Hisanaga MORO, Yosiki TAKAHASI, Osamu NAMURA, Akira SAITO, Nobuo YAGI, ...
1995 Volume 24 Issue 1 Pages
139-142
Published: February 15, 1995
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A new ringed graft with Dacron skirt reinforcing anastomosis with the aorta We developed the ringed graft with Dacron skirt in order to reinforce the anastomosis with the aorta. We implanted this new graft in 11 mongrel dogs, and evaluated the anastomotic tensile strength and pressure tolerance. We examined microscopically the aorttc wall compressed by the Teflon tape one month after implantation.Surgical method was as follows. A Dacron graft of 4cm in length and 12mm in diameter (the portion of skirt) was sutured to a Dacron graft of 8mm in diameter. This 8mm graft was inserted through the stenless ring, and the portion of skirt was folded over. This ringed graft was setted in the end of amuputated aorta and fixed using a Teflon tape, and this skirt was folded over again so that there was the cloth-covered aortic wall. Finally, reinforcing fixation was performed using second Teflon tape andthe graft was sutured through aortic wall. The anastomosis with ringed graft was superior in the tensilestrength and pressure tolerance, compared to those with the end to end anastomosis. Neither amputation nor marked reduction of elastic fiber was observed microscopically, but the aortic wall was slightly compressed with thetape. Inconclusion, our new ringed graft with Dacron skirt is considered to be a useful alternative for replacing in patient with aortic aneurysm, atherosclerotic obliteration.
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N. SUZUKI, Y. OKUDA, S. YAMANOUCHI, T. KUMADA
1995 Volume 24 Issue 1 Pages
143-149
Published: February 15, 1995
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We examined the potential role of luminal surface structure of arterial grafts in the occurrence of anastomotic hyperplasia. Three fluorocarbon rubber grafts with different degrees of luminal pore size were prepared from hexa-fluoropropylene-based copolymer, and interposed into the carotid arteries of rabbits with end-to-end anastomoses. After 4 weeks patent grafts were recovered for histological examination, which revealed a marked increase in thickness and a moderate decrease in longitudinal extension of pannus tissue on to the anastomotic luminal surface of the poorly porous grafts in comparison with the highly porous grafts. The pannus thickness of the proximal and distal regions did not differ from each, other. The anastomotic pannus of the grafts were composed predominantly of smooth muscle cells. Additionally, there observed a less degree of penetration of pannus tissue into the microporous wall in the poorly porous grafts. These observations suggest that unstable anchoring property of compliant micro-porous vascular grafts is a modulating factor for limited extenti.on of pannus and subsequent development of anastomotic hyperplasia.
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K. ISHIBASHI, K. KAWAZOE, T. MATSUDA
1995 Volume 24 Issue 1 Pages
150-155
Published: February 15, 1995
Released on J-STAGE: October 07, 2011
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We developed hybrid grafts hierarchically incorporated with endothelial cells (ECs), smooth muscle cells (SMCs) and fibroblasts (FCs), and investigated the cellular behaviors and ultrastructure of regenerated extracellular matrix (ECM) of those grafts
in vivo. Two models of hybrid vascular grafts were constructed on knitted Dacron grafts (ID=4mm, Length; 6cm)
in vitro. Model I grafts were hierarchically structured with a confluent monolayer of ECs, a middle layer of SMCs and an outer layer of FCs. Model II grafts consisted of a confluent EC monolayer and a homogeneously mixed layer composed of SMCs and FCs pre-labelled with a fluorescent lipid. The designed artificial ECM was a mixed gel of type I collagen and dermatan sulfate. Both grafts were implanted bilaterally in canine carotid arteries of 14 dogs for up to 12 weeks without anticoagulant. Regardless of model type, patent grafts (n=24 out of 28 implanted grafts) were completely endothelialized. In model II grafts at 4 weeks, SMCs migrated to the subendothelial layer, whereas labelled FCs migrated to an outer layer, which was identified under a fluorescent microscope. Observation of both grafts at 12 weeks showed that most of the collagen fibers in the luminal surface layer were longitudinally oriented, but those in deeper layers tended to orient circumferentially, and that newly generated elastic tissues were composed of many concentric laminae. SMCs of both grafts at 12 weeks were predominantly of the contractile phenotype. Thus, it can be said that hybrid grafts incorporating intima-, media- and adventitia-type cell layers can significantly enhance the process of arterial wall reconstruction.
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J HIRAI, T OKA, T MATSUDA
1995 Volume 24 Issue 1 Pages
156-161
Published: February 15, 1995
Released on J-STAGE: October 07, 2011
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We fabricated a hierarchically structured hybrid vascular tissue from vascular cells and collagen and investigated its application to a low pressure loaded venous system. A hybrid medial tissue was prepared by pouring a cold mixed solution of canine jugular smooth muscle cells (SMCs) and type I collagen (SMC density: Sx10
5cells/ml, collagen concentration: 1.5mg/ml) into a tubular glass mold (outer diameter: 24mm, inner diameter: 8mm, length: 8cm) and by subsequent incubation at 37°C. The culture in the medium for 10 days produced an opaque, dense, tubular tissue with a wall thickness of 1mm and an inner diameter of 8mm. After seeding of the jugular endothelial cells (ECs), vascular tissues (n=8) were implanted in the canine posterior vena cava for up to 2 weeks. Three grafts ruptured longitudinally at the midportion on the day of implantation. The wrapping with a Dacron mesh effectively prevented the rupture. In patent grafts, ECs on the luminal surface oriented to the direction of the blood flow at one week after implantation. Accumulation of SMCs beneath the intima and secretion of collagen fibers by ingrown fibroblasts at the outer layer were initiated at two weeks, indicating that the tissue was being remodeling. SMCs in cryopreserved hybrid medial tissues were viable. It is suggested that, after some improvements, hybrid vascular tissues composed of vascular cells and collagen can be applied to a venous system.
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H NAKAJIMA, Y SUZUKI, M IWAKI, A NAKAO, M KAIBARA, M KUSAKABE
1995 Volume 24 Issue 1 Pages
162-167
Published: February 15, 1995
Released on J-STAGE: October 07, 2011
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New hybrid vascular graft was developed. Graft material was segmented polyurethane (SPU) that was induced cell adherence using ion implantation. We analyzed the in vivo anti-thrombogenicity. Substrates were SPU coated glass tube, 1.5 x 50mm, and SPU coated expanded poly-tetrafluoroethylene (ePTFE), 3.0 x 50mm. Inner surfaces of the substrate were implanted Ne
+, 3 x 10
15ions/cm
2 of 150keV energies. Endotherialization of the ion implanted substrates were performed by rotary cultivation method using bovine aorta endotherial cells(1 x 10
15 cells/ml). Endothelial cells were confluent on the inner-surface of the graft after five days' cultures. The glass tube grafts (EC-Ne-G-SPU) were replaced femoral arteries and femoral veins of thirteen dogs until 24 hours, and one ePTFE graft(EC-Ne-ePTFE-SPU) was replaced carotid artery 24 days. EC-Ne-G-SPU replaced into femoral arteries demonstrated 100% (9/9) patency. EC-Ne-G-SPU into the femoral veins 70%(7/10). EC-Ne-ePTFE-SPU was patent at 24 POD. Endothelialization was localized near anastomosis. Conclusion: Development of polymer based hybrid vascular graft was saccessful. Ion implantation might be applied to cell adhesion control of vascular graft.
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M. HAMAGUCHI, K. KATAMI, Y. NOMURA, Y. OKUDA, M. KOMETANI, S. YAMANOUC ...
1995 Volume 24 Issue 1 Pages
168-173
Published: February 15, 1995
Released on J-STAGE: October 07, 2011
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Surface-modified ePTFE grafts (2mm internal diameter and 30μm fibril length) produced by immobilization of gelatinized atelocollagen (GAG) and by intermediary methacrylic acid (MA) grafting were implanted into the carotid arteries of New Zealand White rabbits to study early thrombogenicity, patency, and graft healing. In MA/GAG-immobilized grafts there were observed a smooth and thin fibrin thrombus layer on the luminal surface from 1 day, equivalent patency rates up to 12 weeks, and 3-4 times increase in endothelial coverage at 4 weeks, as compared with those observed in untreated grafts. However, the improved endothelialization was not seen at 12 weeks. Similar results were also obtained with MA-immobilized grafts, and less degree of immobilization of MA or MA/GAG resulted in thinner pseudointima formation at 12 weeks. We suggest that decrease in hydrophobic ity by surface modification promotes the endothelialization of ePTFE vascular grafts without decreasing early patency rates
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T NAGAE, H TSUCHIDA, Samuel E. WILSON, S ISHIMARU
1995 Volume 24 Issue 1 Pages
174-178
Published: February 15, 1995
Released on J-STAGE: October 07, 2011
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EPTFE vascular grafts were modified to produce a highly porous inner layer (inner layer Exp. 1; 60μm, Exp. 2; 90μm, outer layer 20-30μm). The experimental grafts were compared with the high porosity (HP) grafts (Exp. 1-60μm) and the standard (ST) grafts (Exp. 1&2; 20-30μm). These EPTFE grafts, 50mm in length and 4mm in diameter, were implanted in adult female mongrel dogs. In the first experiment, we retrieved each three types of graft at 4 weeks (n=2), 12 weeks (n=5) and 18 weeks (n=9) and in the second experiment, we retrieved experimental grafts and ST grafts at 18 weeks (n=10). We investigated the effect of composite design on the histology of graft healing. Neointimal cells were seen on light microscopy to penetrate the highly porous inner layer, and on SEM, the fibrils appeared to anchor the neointima of the modified graft and in the most advanced sites of intimal extention, neointimal cells and thrombus were observed on the fibrils and the EPTFE nodes are exposed. The area of endothelialization covering the modified EPTFE was 54, 9% (Exp. 1) and 58.8% (Exp. 2) at 18 weeks, HP was 84.8% (Exp. 1), and ST, 27.4% (Exp. 1) and 26.8% (Exp. 2) at 18 weeks. We conclude that modified EPTFE grafts with a inner layer of 60-90μm have enhanced formation and anchoring of neointima.
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S. TERADA, M. NOZAKI, K. SUZUKI, T. OKANO, N. TAKEMURA
1995 Volume 24 Issue 1 Pages
179-184
Published: February 15, 1995
Released on J-STAGE: October 07, 2011
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A new rabbit model of free-tissue transfers was developed for small-caliber vascular grafts under a microcirculatory condition. This study investigated the survival of free-tissues and the patency of prostheses connecting flap pedicles and recipient vessels without an arterio-venous shunt at the end of the pedicles. The 15mm-long vascular grafts were made of polyurethane with an inner diameter of 1.4mm and an outer diameter of 1.8 to 2.1mm. The inner surface was coated with 2-hydroxyethylmethacrylate (HEMA)-styrene block copolymer and argatroban, which were anti-thrombogenic to platelets and thrombin. Epigastric flaps (n=5) were elevated with inferior epigastric and femoral pedicles. The flaps were moved to the abdominal cavity and the pedicles anastomosed to the renal vessels with the vascular grafts. After the 1 week experimental period, two flaps had survived (40% survival rate). In the survived flaps only the grafts in the arterial circuit were patent, but the grafts in the venous circuit were occluded. Ultrasonography was used to demonstrate a flow of 2.2±2.6ml/min in the arterial pedicle. Heterotropic intra-abdominal implantation of rabbit epigastric flaps is possible with small-caliber vascular grafts.
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K KANDA, S SATOH, T OKA, T MATSUDA
1995 Volume 24 Issue 1 Pages
185-189
Published: February 15, 1995
Released on J-STAGE: October 07, 2011
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We have developed a small diameter vascular prosthesis mainly composed of circumferentially-oriented dense collagen fibers. A tubular-shaped hybrid tissue (outer diameter (OD): 9mm, inner diameter (ID): 1.5mm, length: 70mm) was prepared by thermal gelation of a cold mixed solution of bovine aortic smooth muscle cells (SMCs) and bovine derma type I collagen in a tubular mold. Upon incubation for 10 days, a dense, highly-oriented and elastomerc tubular organism (OD: 3mm, ID: 1mm, length: 20mm) was assembled by the traction force of SMCs, which was subsequently cross-linked with 1% glutaraldehyde for an hour, freeze-dried and sterilized to be stored as an elastomeric small diameter vascular prosthesis. The grafts (OD: 3mm, ID: 1mm, length: 10mm), to the luminal surfaces of which heparin-protamine complex had been applied, were implanted to the aortas of rats for up to 30 weeks. No occlusion, no pseudoaneurysm formation nor disruption of the grafts were observed throughout the implantation periods. Morphological investigation revealed that the luminal surfaces of the grafts were completely covered with endothelial cell monolayers within 4 weeks. The maximal thickness of subendothelial layer observed for 4-week implant was around 15μm, that decreased with time. The graft is expected to induce rapid tissue regeneration and substitution.
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K. DOI, Y. NAKAYAMA, T. OKA, T. MATSUDA
1995 Volume 24 Issue 1 Pages
190-194
Published: February 15, 1995
Released on J-STAGE: October 07, 2011
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Multiply pored structure was prepared on polyurethane tubes by an excimer laser ablation technique to provide its compliance matching with host tissues as well as to promote transmural tissue-ingrowth of vascular prosthesis. Three types of microporous tubes (2mm internal diameter, 100μm wall thickness) were designed as follows: Pore size (100μm) and pore-to-pore distance at longitudinal configuration (200μm) were set constant, but pores at circumferential configuration were prepared at every 60° (type 1), 30° (type 2) and 15° (type 3). The processed prostheses were coated with photoreactive gelatin, which was photogelled by ultraviolet irradiation. Scanning electron microscopic observation showed that pore size and its arrangement were precisely controlled as designed, and that a gelatinous hydrogel was formed to provide a smooth layer over the entire luminal surface. The compliance of these processed tubes was determined by measurement of external diameter change responding to intraluminal pressure increase, which was translated into a stiffness parameter (β). An increase of number of pores at circumferential configuration decreased β value, which indicates enhanced elastic property. β value of type 3, which was the most compliant among the three types, was found to be 37.7, which is close to that of human coronary artery (β: 39.8). By combination of excimer laser directed microprocessing techniques and photochemical surface process a compliant prototype small-caliber vascular prosthesis was developed, which is expected to enhance tissue ingrowth in vivo.
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K MORIZAWA, K AWAI, K AKAMA, S TOKUYAMA, T SATOH
1995 Volume 24 Issue 1 Pages
195-200
Published: February 15, 1995
Released on J-STAGE: October 07, 2011
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We examined the effect of polymerizable phospholipid vesicles encapsulated hemoglobin (ARCs) on the murine immune system.The phagocytic ability of reticulo endothelial system was studied by measuring carbon and congo red clearance rate, and vital resistance to LPS. We also investigated the influences on blastogenesis and NK activity of the spleen lymphocytic fraction. Except for the disturbance of splenic phagocytic activity at early period of dosing, ARCS do not significantly influence on the murine immune system. The transmission electron microscopic observation of the spleen showed that there were swollen particles inside the phagocytic cells such as macrophages at 1 day after dosing, but these were extinguished at 30 days after.
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Akira USUBA, Ryoichi MOTOKI, Yoshitaka OGATA, Kazuhiko SUZUKI
1995 Volume 24 Issue 1 Pages
201-205
Published: February 15, 1995
Released on J-STAGE: October 07, 2011
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Fluosol-DA (FDA) is the first blood substitute to be clinically applied, providing a note-worthy experience in the clinical field. Liposome encapsulated hemoglobin, Neo Red Cells (NRC), are approaching the stage of clinical use. FDA and NRC were predicated on the basis of the results of clinical use of FDA. Hemorrhagic shock: Adult mongrel dogs under mechanical ventilation were placed in the condition of shock by exsanguination, and treated by auto transfusion with blood substitutes. This procedure was repeated three to five times. Group NRC inhaled room air, and Group FDA 100% O
2. The rate of final blood exchange was 59-88% in Group NRC and 36-86% in group FDA. After blood exchange, overall peripheral vascular resistance deceased, and the cardiac index increased markedly. We regard to oxygen transport, Group NRC showed an oxygen consumption rate of 60.5% (rate of exchange, 88%) and Group FDA showed a contribution rate of 30.1% (rate of exchange, 86%). Extracorporeal circulation: Exsanguination of the right atrium and revascularization from the aorta in extracorpoeal circulation were performed for three hours by filling blood substitutes in adult mongreal dogs. The dog treated with filling of whole blood served as controls. Group NRC showed about 1/3 of the whole peripheral vascular resistance level in the control group, but the contribution rate of NRC to oxygen transport in Group NRC was superior to that in Group FDA.
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K. HANZAWA, H. OHZEKI, H. MORO, J. HAYASHI, S. EGUCHI, T. NAKAJIMA, T. ...
1995 Volume 24 Issue 1 Pages
206-210
Published: February 15, 1995
Released on J-STAGE: October 07, 2011
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The protective effect of partial blood replacement with two kinds of artificial blood substitutes against cerebral ischemic injury was evaluated using cerebral ischemic model (Kirino model). 77 adults male gerbils of body weight 80g were used for experiments. [Experiment 1] At first, partial blood replacement with Fluosol DA (FDA) was perfomed and the animals were observed with room air for a week. [Experiment 2] In the Group A, 5ml of blood was replaced with FDA, and 24 hours later, bilateral carotid arteries were occluded for 5 minutes. In the Group B, the same amount of blood was replaced with FDA, and in the Group C, bilateral carotidwere occluded without pretreatment. The Group D was control. [Experiment 3] In the Group E, 5ml of blood was replaced with pyridoxalated hemoglobin polyoxyethylene (PHP) and immediately followed by bilateral carotid artery occlusion. In the Group F, the same amount of blood was replaced with PHP, and in the Group G and H, the test was perfomed as in the Group C and D. All subjects were sacrificed and number of intact hypocampul CA l cells were counted 7 days after the test. Exchanging transfusion with 5.0ml FDA, all treated animals were survived for a week. The number of intact cells per one field of view was 81.6±16.7, 132±5.9, 6.9±4.5 and 142±16.0 in the GroupA, B, C and D, respectivery(Group A vs C, p<0.001). And it was 27.4±10.1, 142±4.5, 38.1±12.7, and 140.1±2.3 in the Group E, F, G and H, respectivery (Group E vs G, N. S.). In conclusion, partial blood replacement with FDA prior to carotid arteries occlusion is considered to be an effective pretreatment against ischemic brain injury.
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K NAKAI, H ABE, TA TAKAHASHI, S. SEKIGUCHI
1995 Volume 24 Issue 1 Pages
211-215
Published: February 15, 1995
Released on J-STAGE: October 07, 2011
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An inhibition enzyme immuniassay (EIA) was developed to quantify blood group antigen in stroma-free hemoglobin (SFH). Glycophorin A bearing type A antigenicity was purified and used for coating ETA plates and as the standard. The lower detection limit was 0.3ng/well, which value was 10-fold more sensitive than that by the hemagglutination inhibition test (HAI). Both assays were applied to compare six representative SFHs. The Rabiner's conventional SFH and heat-treated SFH were shown to contain a significant amount of antigen at 8.40-8.70ng/mg of hemoglobin by ETA, and also positive by the HAT. In contrast, other SFHs prepared by acid-treatment, chloroform extraction, or ultrafiltration were negative by HAI, but EIA successfully revealed that the SFHs still contained the antigen in the range of 0.46-0.84ng/mg. These results indicate that these SFHs are 10 times purer than the conventional SFH. EiA is sensitive, fast and easy to perform, and is therefore a useful tool for the quality control of SFH.
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K. SUZUKI, Y. KAGEYAMA, M. TAKINAMI, Y. HARADA, T. KOKUBO
1995 Volume 24 Issue 1 Pages
216-220
Published: February 15, 1995
Released on J-STAGE: October 07, 2011
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An experimental study of an artificial polymer trachea coated with hydroxyapatite was performed. Two types; end-to-end anastomosis type and Neville type, were made and the cervical trachea of mongrel dog was replaced by a prosthesis. The comparative studies between a hydroxyapatite coating group and a non-coating group in each type were performed. The survival rate in the coating group was significantly higher than that in the non-coating group, and granulation tissue formation, dehiscence of anastomosis and infection were frequent in the non-coating group. These results showed that hydroxyapatite was useful as a coating material of a prosthesis for its good histocompatibility and adhesiveness to the surrounding tissues
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T FUJIMOTO, Y KATOU, K NAEMURA, H FUJIMASU, M UMEZU
1995 Volume 24 Issue 1 Pages
221-225
Published: February 15, 1995
Released on J-STAGE: October 07, 2011
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A mechanical circulatory system (MCS) has been developed in order to evaluate artificial organs, including circulatory assist devices and artificial prosthetic heart valves. An effective functioning MCS, which is similar to the natural system, would allow us to use it as a substitute for animal experimentation. The purpose of this study is to reproduce the aorta in the MCS. This simulator includes a fluid circuit, drive and measuring systems. The fluid circuit consists of an artificial atrium, ventricle and aorta which physically and functionally designed to be almost identical to those of natural organs with reference to an anatomical weight of 60kg. Input impedance was calculated with a personal computer from pressure and flow rate measured at the aorta in the MCS. The impedance analysis data from the silicone aorta indicated that at a minimum modulus of impedance occurred at the 4th harmonics in phase. This input impedance pattern obtained was close to that of the natural aorta.
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H. ARAKI, T. TANI, T. YOKOTA, K. NUMA, Y. TSUTAMOTO, H. OKA, Y. EBIRA, ...
1995 Volume 24 Issue 1 Pages
226-228
Published: February 15, 1995
Released on J-STAGE: October 07, 2011
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The microcapsules were made of lactic acid and glycolic acid copolymer (PLGA). The cisplatin containing microcapsules (CDDP-MC) were prepared using the liquid drying technique. The release of cisplatin from CDDP-MC was tested in vitro. The residual quantity of cisplatin was measured at regular intervals. The residual rate was approximately 81.2% on the first day, 63.8% on the third day, and 6.4% on the tenth day. After 14 days, the entire contents of the microcapsules had been released. The antitumor effect of CDDP-MC against MKN-1 and Ehrlich's ascites cell lines was confirmed.
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H KITO, F SUZUKI, N TSUTSUI, N NAKAJIMA, T MATSUDA
1995 Volume 24 Issue 1 Pages
229-232
Published: February 15, 1995
Released on J-STAGE: October 07, 2011
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The development of a percutaneous procedure using a catheterized system with the function of drug delivery to diseased vessels has been increasingly demanded for minimized restenosis. A coaxial double balloon catheter, at the tip of which an inflatable and drug-releasing double balloon was installed, was developed. The outer balloon was fabricated to have micropores (diameters: 20 & 30μm) by an excimer laser ablation technique, from which a drug-containing solution was released upon inflation of the inner balloon. Scanning electron microscopic observations of the outer surface of the balloon indicated that laser-directed microporing including its size and distribution were precisely controlled using our technique. The outflow rate linearly increased with increase of infusion pressure. Outflow rate per pressure directly related to the pore size. These results indicate that the newly devised catheter may promise to realize local delivery of therapeutic agents at the diseased site shortly after mechanical balloon dilatation.
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Y. INOUE, R. YOZU, A. MITSUMARU, S. KAWADA
1995 Volume 24 Issue 1 Pages
233-238
Published: February 15, 1995
Released on J-STAGE: October 07, 2011
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Although percutaneous balloon valvuloplasty is widely accepted, post-precedural complications are still reported and reduce its efficacy and long term results. We explored the feasibility of percutaneous laser valvuloplasty assisted by cardioscopy in an experimental setting in ordr to eliminate these risks. Laser balloon tipped endosope, thin laser probe, and a Nd-YAG laser transmitter were used as our working model. A porcine pulmonary valve is our in-vivio target of laser ablation in a beating heart. Under general anesthesia, the endoscopic catheter is delivered into the right ventricle from either internal jugular or femoral vein. Manipulation of the catheter and positioning the pulmonary apparatus coaxial to the endoscopic field of vision, allowed us for targeting and ablating the comissure of the pulmonary valve under direct view. The animal was then sacrificed for the histopathological study. The commissure was smoothly ablated, and the entire procedure was successfully observed through the cardioscopy. We encountered some difficulties in limitations to the endoscopic field of vision, laser targeting, and dfficulty in stabilizing the visual field in the beating heart. These are the barriers to overcome for the future clinical application of this procedure. However, these results indicate a clear possibility for the future use of cardioscopy-guided percutaneous laser valvuloplasty in a clinical setting.
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