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T Nishibe

Publications and source records attributed to T Nishibe.

49 records · Page 3Linked to original sources
PubMed1998

Rapid arterial anastomosis with titanium clips.

BACKGROUND: The obvious advantages of rapid arterial anastomoses have prompted the continuing search for more rapid anastomotic techniques to complement the standard sutured anastomosis. Nonpenetrating, arcuate-legged titanium vascular closure staple (VCS) clips were initially developed for microvascular anastomoses. The purpose of this study was to compare VCS clips with sutured arterial end-to-end anastomosis in larger vessels. METHODS: In 6 pigs, transacted iliac arteries were reanastomosed with VCS clips on one side and continuous 6-0 polypropylene suture on the other. RESULTS: The reconstruction time was 8.4+/-5.2 minutes for clip closure and 12.0+/-6.6 minutes for suture closure (P = 0.033). All vessels were patent half an hour after completing the anastomoses with no signs of early thrombosis. CONCLUSIONS: Arterial end-to-end anastomosis can be performed more rapidly with VCS clips than continuous sutures, and are potentially useful in situations where the clamp time of the vessel is critical.

Anastomosis, Surgical↗
PubMed1998

Arterial reconstruction with vascular clips is safe and quicker than sutured repair.

BACKGROUND: Non-penetrating, arcuate-legged vascular-closure staple clips made of titanium were initially developed for microvascular anastomoses with little experience of their use in larger vessels. The purpose of this study was to compare vascular-closure staple clips to sutured anastomoses in common iliac arteries in a porcine model. METHODS: In an experimental study, transected iliac arteries on both sides of 11 pigs were randomly assigned to end-to-end anastomosis performed with vascular-closure staple clips or interrupted 6-0 polypropylene sutures. Angiographic, macroscopic and microscopic results were assessed after 2 months. RESULTS: There was no significant difference in the patency rate, tensile strength of the anastomoses, vessel diameter at the repair site, intimal thickness or wall thickness of the arteries after either method of closure. The mean (s.d.) clamp time was 19.8 (6.1) minutes for clip repair, and 36.0 (6.9) seconds for suture repair (P < 0.001). The times required for the reconstruction of the anastomoses were 17.4 (6.1) and 35.5 (7.1) minutes, respectively (P < 0.001). CONCLUSIONS: Arterial anastomoses performed with vascular-closure staple clips are faster than sutured anastomoses, and result in comparable wound healing when assessed for patency, tensile strength, degree of narrowing and intimal reaction.

Anastomosis, Surgical↗
PubMed1997

Experimental replacement of the thoracic inferior vena cava with a high-porosity expanded polytetrafluoroethylene graft wrapped in an omental pedicle flap.

We examined the patency and healing of a high-porosity expanded polytetrafluoroethylene (ePTFE) graft implanted as an interposition graft in the thoracic inferior vena cava (IVC) and wrapped in an omental pedicle flap. High-porosity ePTFE grafts of 60 microns fibril length, with an internal diameter of 10 mm and a length of 4 cm, were implanted in 12 mongrel dogs. In 6 dogs, the grafts were wrapped in omental pedicle flap, and in the remaining 6 the grafts were unwrapped. The animals were killed 4 weeks after the replacement and the grafts were removed for examination. Patency of the graft in both groups was 100%; however, the thrombus-free area in the omentum-wrapped group was significantly larger (P < 0.05) than that in the unwrapped group. Light microscopy revealed the marked infiltration of cells and capillaries within the graft interstices in the omentum-wrapped group. These findings suggest that encapsulation of the high-porosity ePTFE graft is promoted by an omental pedicle flap.

Anastomosis, Surgical↗
PubMed1997

Expanded polytetrafluoroethylene grafts for portal vein replacement: use of omentum wrap to promote graft healing.

This study was designed to reexamine the healing process of expanded polytetrafluoroethylene (EPTFE) grafts with standard porosity (30 microm) and high porosity (60 microm) in portal vein replacement, and to evaluate the effect of an omentum wrap, which has certain functions that promote healing, on graft healing. These grafts, either wrapped by the omentum or not, were placed as portal vein replacements in 24 mongrel dogs. After 1 month, the grafts were retrieved and examined for patency, thrombus-free areas, thickness of the pseudointima, and the total number of cells growing into the graft wall. There were no statistical differences in the patency rates. The high-porosity grafts had a significantly larger thrombus-free area, a thicker pseudointima, and a larger growth of cells than the standard-porosity grafts. The omentum wrap significantly increased the thrombus-free area and stimulated a larger growth of cells in both grafts. The high-porosity grafts plus omentum demonstrated a thrombus-free area of 82.2% vs 27.3% in the standard-porosity grafts. In addition, the migration of fibroblasts and macrophages was most evident in the high-porosity grafts wrapped by the omentum. In conclusion, graft healing enhancement was observed in the high-porosity EPTFE grafts wrapped by the omentum. It is thus suggested that transmural cellular migration plays an important role in the process of graft healing.

Animals↗
PubMed1996

Value of intraoperative intrathoracic ultrasonography during video-assisted thoracoscopic pulmonary resection.

Recent advances in endoscopic surgical equipment, video monitoring, and endoscopic surgical techniques have expanded the application of thoracoscopic surgery to pulmonary resection. One of the major limitations of this technique is the difficulty in identifying invisible pulmonary nodules in which manual palpation is not possible. To resolve this problem, we employed intraoperative intrathoracic ultrasonography during video-assisted thoracoscopic pulmonary resection. We conclude that intraoperative ultrasonography during thoracoscopic pulmonary resection is useful to identify pulmonary nodules, except inflammatory lesions.

Adult↗
PubMed1995

[Thoracoscopic surgery, current indication and technique].

Thoracoscopy has become an important tool in the diagnosis and management of intrathoracic disease. The development of endoscopic suturing techniques and stapling devices for abdominal surgery dramatically expanded the potential of thoracoscopic surgery. Between 1993 and 1994, 43 patients underwent thoracoscopic surgery. Lung resection were performed on 23 patients for pulmonary nodules and on 9 patients for diagnosis of interstitial lung disease. Extirpation were performed on 2 patients for mediastinal tumor. A procedure done thoracoscopically is far less invasive and the postoperative pain and its consequences are drastically reduced. As endoscopic instrumentation develops, newer operations will become technically feasible. We think that indications for thoracoscopic surgery will expand in developing these techniques in the future, if thoracoscopic surgery is safer and more efficient.

Adult↗
PubMed1993

[Clinical evaluation of hepatic blood flow and liver function with 99mTc-DTPA-HSA].

Clinical evaluation of hepatic blood flow and liver function of 30 patients with 99mTc-human serum albumin scintigraphy (99mTc-HSA) was done. In this study we evaluated the ratio of portal venous to total hepatic blood flow as the hepatic perfusion index (HPI), and 99mTc-HSA uptake ratio of the liver to the heart at 2 hrs after bolus injection as the hepatic uptake score (HUS). In clinical study, we estimated both HPI and HUS in patients with liver cirrhosis (LC) and non-liver-cirrhosis (non-LC), and in the same way estimated these two factors in the patients before and after distal splenorenal shunt operations (DSRS). We also estimated the correlation of both HPI and HUS with other liver functions. Finally we made 3 dimensional liver imagings using 99mTc-HSA. The mean HPI was 0.42 +/- 0.24 in the LC group and 0.66 +/- 0.19 in the non-LC group (p < 0.02). The mean HUS was 0.50 +/- 0.17 in the LC group and 0.67 +/- 0.13 in the non-LC group (p < 0.02). The mean HPI decreased to 32-54% after the DSRS operation, but there was no such change with HUS. Correlation between HPI and KICG was significant (r = 0.51, p < 0.02), and there was also a correlation between HUS and PT, HPT (p < 0.02), and ICGR15 (p < 0.02). We concluded that HPI and HUS were both useful factors in estimating hepatic blood flow and liver function.

Female↗
PubMed1991

Tc-99m labeled tissue-type plasminogen activator: preparation, stability and preliminary imaging of thrombus-bearing rats.

Tissue-type plasminogen activator (t-PA) is a thrombolytic agent that directly binds to fibrin formed in clots. In terms of radiolabeling and nuclear imaging, t-PA has several advantages in Tc-99m labeling: it is stable in acidic solution at pH 3, which is suitable for labeling Tc-99m by a method of stannous reduction and blood disappearance after administration is rapid, which is desirable for imaging targets using short-lived radionuclides. Recombinant t-PA was labeled with Tc-99m by a method of stannous reduction without significant degradation of biochemical activity, over 95% of which was retained after the labeling procedure. Labeling efficiency in paper chromatography was over 98%. The moiety of hydrolyzed Tc-99m that was not eluted through the Sephadex column was estimated to be less than 10%. Tc-99m labeled t-PA, however, appeared to become unstable when diluted with normal saline. Nevertheless, in in vitro fibrin binding, Tc-99m labeled t-PA showed high affinity with fibrin: 80% of 100 ng/ml of Tc-99m t-PA bound to 10(-5) mol of the fibrinogen. Preliminary animal studies also showed a concentration of Tc-99m labeled t-PA at fresh thrombi formed in the inferior vena cava. Tc-99m labeled t-PA appears to have potential for thrombus imaging and the preparation of an instant kit.

Animals↗
PubMed1991

[Study on patency of small caliber synthetic vascular prosthesis--with special reference to antithrombogenesity of fibrin layer].

The influence of antithrombogenesity of stable and thin fibrin layer on patency of small diameter graft was studied. Newly developed segmented polyurethane grafts (SPG), 4 cm in length and 3 mm in internal diameter, were interposed between divided carotid arteries in 20 mongrel dogs. The change of antithrombogenesity was evaluated by 111In-oxine labeled platelet scintigraphy. Autologous radiolabeled platelets were injected immediately or 1 week after implantation. Grafts and native arteries were explanted 48 hours after injection, and submitted for gamma well counting. Platelet accumulation was quantitated by a Graft/Blood Ratio (GBR) that compared radio-activity in the graft or native artery (luminal surface area 1 cm2) to simultaneously collected blood (1 ml). In SPG, GBR was significantly declined during 1 week (2.65 +/- 0.65 in immediate group, 0.72 +/- 0.18 in early group, p less than 0.05). Also each GBR in immediate or early group was by far greater than GBR in native arteries. Histologically the luminal surface in patent grafts was thinly covered with the fibrin layer, which was anchored firmly to the porous structure. On the other hand thrombus was formed at the anastmotic site in obstructive grafts. In conclusion, the stale and thin fibrin layer formed on the luminal surface has a reduced thromboactivity and maintains early graft patency. However its antithrombogenesity is far beyond that of native arteries and limits patency.

Animals↗
PubMedDate not supplied

The influence of node-fibril morphology on healing of high-porosity expanded polytetrafluoroethylene grafts.

PURPOSE: To manufacture high-porosity expanded polytetrafluoroethylene (ePTFE) vascular grafts with the same internodal distance but different node-fibril morphology, and to evaluate their biologic behaviors in a canine carotid artery implantation model. MATERIALS AND METHODS: Several types of high-porosity ePTFE vascular grafts with the same inside diameter (4 mm) and wall thickness (650 microm) were manufactured under different heating, stretching conditions. The luminal surface and cross section of the grafts were photographed by scanning electron microscopy and the node-fibril structure was examined. Two typical types of high-porosity ePTFE vascular grafts were then selected and proceeded to an animal study. The test grafts were explanted after an interval of 12 weeks and subjected to histomorphometric analyses. RESULTS: The following two types of high-porosity ePTFE vascular grafts were selected; one had a through-pore structure extending from the outer to the inner surface and the other had a random-node architecture with tortuous path channels extending from the outer to the inner surface. The histomorphometric analyses of thrombus-free surface, thickness of pseudointima, cellular ingrowth, capillary ingrowth, and cellular proliferation revealed no significant differences between the grafts. CONCLUSION: In high-porosity ePTFE vascular grafts, graft healing enhanced by transmural tissue ingrowth may be not largely dependent on node-fibril morphology. This knowledge will be helpful to design a new type of high-porosity ePTFE vascular grafts available for clinical use.

Animals↗