Activation of the coagulation system by contact of circulating blood with tissue factor, a component of the extrinsic blood coagulation pathway that is produced in the vessel wall, may represent a pathway for the initiation of thrombosis in atherosclerotic vessels. This hypothesis was tested in vivo in a rabbit femoral ...

Regional ischemia may induce cervical anastomosis leakage or stenosis or graft necrosis after esophageal reconstruction by retrosternal interposition of an ileocolic graft. These complications may be related to systemic or local hemodynamic alterations. This study was designed to evaluate the relationship between immediate postoperative arterial blood supply to the graft, ...

Every effort to reduce synthetic graft infection is welcome and when designing antibiotic-bonded grafts it is important not to increase graft thrombogenicity. In order to study the acute thrombogenicity of rifampicin-soaked gelatin-sealed Dacron grafts compared with untreated gelatin-sealed Dacron grafts, an experimental carotid artery sheep model was used. Twenty sheep ...

To evaluate the effects of competitive flow, bilateral aorto-iliac ePTFE grafts, 10 cm in length and with an internal diameter of 6 mm, were placed in ten mongrel dogs. On one side the external iliac artery was ligated (the control side); on the opposite side (the experimental side) flow continued ...

In 30 patients undergoing femoro-distal bypass the effect of papaverine and praxilene on blood flow in the graft was measured. The mean resting flow was 129 ml min-1 (range: 91-167) and after papaverine was 202 ml min-1 (142-262) and after praxilene was 205 ml min-1 (143-267). Praxilene has a similar ...

All anastomotic intimal thickening may not be the same, and the underlying mechanism(s) regulating the different types may vary. We investigated the localization of experimental anastomotic intimal thickening in relation to known biomechanical and hemodynamic factors. Bilateral iliofemoral saphenous vein and polytetrafluoroethylene grafts were implanted in 13 mongrel dogs. The ...

Longitudinal elasticities of whole human blood clot, whole canine blood clot, Factor XIII cross-linked fibrin, glutaraldehyde-fixed human albumin, and formaldehyde-fixed collagen, gelatin and collagen/gelatin were determined and normalized to human whole blood clot. Matrices of a knitted Dacron graft were then impregnated with albumin, collagen, and collagen/gelatin and their longitudinal ...

Attempts have been made to correlate small-diameter vascular graft patency with compliance matching between the graft and the host artery. Without knowledge about the mechanisms of failure by compliance mismatch, however, such correlations remain empirical. We have developed a flow system which mimics the flow in peripheral arteries and techniques ...

Forty-two femoro-distal vein grafts were studied in the early post-operative period for up to 1 week using a newly developed Doppler monitoring system designed to make frequent, automatic assessments which were stored on tape. Thirty-three grafts remained patent at 1 month with clinical improvement but in nine cases, all performed ...

A randomised placebo-controlled trial was conducted to investigate the effect of iloprost, a stable prostacyclin mimetic, on peripheral resistance during femoro-distal bypass. Patients undergoing femoro-distal long saphenous vein bypass for critical ischaemia received 3000 ng of iloprost or placebo infused into the graft via an unligated side branch over 2 ...

Transcutaneous doppler ultrasound was used to examine internal-mammary-artery (IMA) blood-flow in 26 patients with IMA coronary bypass grafts. The ungrafted right IMA could be seen in all of 19 patients, the grafted left IMA in 16 of 26, and the grafted right IMA in 3 of 7. The velocity profile ...

Blood flow changes during reduction mammaplasty were studied using laser Doppler flowmetry. Twenty-one patients (39 breasts) were entered into the study. Eight patients underwent a modified Skoog mammaplasty, 6 a central glandular pedicle mammaplasty, 2 an inferior pyramidal dermal flap mammaplasty, and 5 a glandular resection with free nipple grafts. ...

Fecal diversion has been implicated as an etiologic factor in anastomotic stenosis following colorectal surgery, particularly following the use of circular anastomotic stapling devices. However, experimental confirmation of the effects of fecal diversion on anastomotic healing is virtually nonexistent. The purpose of this study was to serially evaluate colorectal anastomotic ...

A new microsurgical triangular cutting scissors facilitating end-to-side anastomoses has been developed. The instrument removes oval pieces of tissue from the vascular wall with a single cut. This has several advantages over conventional double cuts with straight microscissors. Preferential use of end-to-side anastomoses has been advocated by several authors, one ...

Hyperacute discordant xenograft rejection can be simulated by blood perfused working isolated heart. The survival of the heart is dependent on its functional integrity, and the preparation is thus sensitive to early myocardial damage. Perfusion of rabbit hearts with human blood results in immediate graft destruction by a thrombotic process. ...

Hyperacute discordant xenograft rejection can be simulated by a blood-perfused working isolated heart. The survival of the heart is dependent on its functional integrity, and the preparation is thus sensitive to early myocardial damage. Perfusion of rabbit hearts with human blood produces immediate graft destruction by a thrombotic process which ...

The role of trace elements in the wound-healing process is still controversial. Their variations within a normal colonic wound healing have never been studied. An experimental study on rabbits was designed to study magnesium, iron, copper and zinc variations in blood, normal colonic walls and colonic anastomoses on each of ...

A randomised placebo-controlled trial was conducted to investigate the effects of iloprost, a stable prostacyclin analogue, on peripheral resistance, during femoro-crural arterial bypass. 3000 ng of iloprost, infused into the graft, produced an immediate drop in peripheral resistance by a mean (range) of 43% (4-80%; p less than 0.01, Wilcoxon). ...

Gas trapped in the interstices of the biomaterials used for vascular prostheses causes thrombosis, and the process of eliminating this gas is known as denucleation. An apparatus was developed for testing in the in vitro effects of denucleation on 4 mm I.D. expanded polytetrafluoroethylene (ePTFE) Vitagraft (Johnson and Johnson). The ...

Perivascular sympathectomy, used for treating patients suffering from vasospastic disorders of the hand, is believed to cause an increase in the distal blood flow. Its effects were examined here by performing the operation on the metacarpal arteries of the left forepaw of ten New Zealand White rabbits, the right forepaw ...

Flow characteristics near the end-to-end anastomosis of vascular graft were studied in model tubes by flow visualization techniques. Artery and vascular graft were modelled by an elastic tube fabricated from an elastomeric polymer and a rigid plastic tube, respectively. Anastomotic models were made by connecting these two tubes, which had ...

A randomised placebo-controlled trial was conducted to investigate the effects of iloprost, a stable prostacyclin analogue, on peripheral resistance, graft blood flow and mean systemic arterial blood pressure (MABP) during femoro-crural arterial bypass. 3000ng of iloprost, infused into the graft, produced an immediate drop in peripheral resistance by a mean ...

The effect of different aprotinin applications on hemostatic changes and blood product requirements in orthotopic liver transplantation was investigated in a prospective, open, and randomized study. From November 1989 to June 1990, 13 patients received aprotinin as a bolus of 0.5 Mill. Kallikrein inactivator units (KIU) on three occasions in ...

Dogs given total-body irradiation and marrow transplants from DLA-identical littermates exhibit prompt and sustained hematopoietic engraftment. However, animals given three preceding blood transfusions from the marrow donor before transplant become sensitized and reject the marrow graft. Rejection is due to exposure to polymorphic minor non-DLA histocompatibility antigens expressed on blood ...

Intimal hyperplasia is a primary cause of failure after vascular reconstruction and may be affected by blood flow. We have studied the effects of increased blood flow on intimal hyperplasia in porous polytetrafluoroethylene grafts implanted in baboons. These grafts develop an endothelial lining by 2 weeks and neointimal thickening due ...

We have described previously the acute sternal devascularization produced by mobilization of one or both internal mammary arteries (IMAs). The present experiments were conducted to examine the time course of sternal revascularization and infection patterns after IMA use. Twenty-four 8-week-old domestic pigs were obtained from a herd in which active ...

Vasoactive agents are commonly used in the postcardiopulmonary bypass period to elevate the mean arterial pressure of myocardial revascularization patients. Concern exists that administration of vasoactive agents in this setting may affect flow through saphenous vein and internal mammary artery grafts. Twenty-eight patients were randomly assigned to receive one of ...

Five dogs, 10 weeks old, underwent operation using ketamin-HCl anesthesia and end-to-end anastomoses of the femoral and brachial arteries were made using polyfilament nonabsorbable material (Ethibond), monofilament nonabsorbable material (Prolene), polyfilament absorbable material (Vicryl) and monofilament absorbable material (PDS). The arterial diameter using a micrometer and blood flow using an ...

To clarify whether or not changes in wall shear stress play a determinant role in the induction of anastomotic intimal hyperplasia of polytetrafluoroethylene (PTFE) grafts, two experimental models were devised. Based on our previous study (J Vasc Surg, 1985), wall shear stress was defined by variation of wall shear stress ...

Various models have been proposed to examine blood-prosthetic materials interactions in terms of the effect of the prosthetic material on platelet structure and function, blood coagulation and fibrinolysis, and tissue infiltrates (cellular or acellular). In addition, these models have been used to examine the change in the graft surface over ...

In 10 pigs a nonsutured, glued colonic anastomosis was constructed with a modified stapling device without staples and compared with an EEA-stapled anastomosis and a one-layer-sutured anastomosis concerning radiologic appearance, breaking strength, circulation, and collagen concentration. 141Ce-labeled microspheres were used for measurements of the anastomotic blood flow before the animals ...

Endothelial cell (EC) seeding is postulated as a mechanism of improving patency of small calibre vascular grafts. However, the majority of seeded cells are lost within hours following restoration of blood flow. We postulated that incubating EC in-vitro on a graft will improve adherence and resistance to the sheer stresses ...

A mathematic model of unilateral iliac vein obstruction was used to establish the theoretic basis for selecting saphenous vein or a larger diameter prosthetic cross-femoral venous bypass graft for relief of obstructive venous hypertension. Common femoral vein resting and postexercise peak flows, and common femoral vein and saphenous vein diameters ...

A simple infusion system to assess the status of distal runoff was investigated on both hindlimbs of five mongrel dogs. Infusion catheters were placed in the superficial femoral arteries and the origin of the lower leg arteries was exposed for anatomic manipulation of the distal runoff. Saline solution was infused ...

Angiogenesis and patency of blood vessels were analyzed qualitatively in solid CNS and peripheral tissue syngeneic, allogeneic, and xenogeneic grafts and in individual cell suspension grafts of astrocytes, fibroblasts, PC12, and three additional tumor cell lines placed intracerebrally in adult host mice. Postgrafting survival times were 1 day through 4 ...

Regional ischemia may induce anastomotic leakage or stenosis after esophageal reconstruction using retrosternal interposition of an ileocolic graft. These complications may be related to systemic or local hemodynamic alterations. This study was designed to evaluate the influence of inhalational anesthetic agents on the intestinal circulation supplying these ileocolic grafts. Seven ...

A system for monitoring blood flow in femorodistal vein grafts with Doppler ultrasonography in the immediate postoperative period has been developed. Twenty-three grafts have been monitored for periods of up to 72 hours. Seventeen grafts have remained patent at minimum follow-up of 6 months, and six grafts occluded in the ...

The caudal gluteal vascular bundle was analyzed in the dog to determine its suitability as a recipient area for free vascularized bone grafts in the femur. The anatomy of the caudal gluteal artery and vein, as well as the arterial blood flow, were studied. This bundle was also used to ...

The importance of blood and extracellular matrix precoating of expanded polytetrafluoroethylene (ePTFE) grafts on the effectiveness of endothelial cell (EC) seeding was assessed in a canine experimental model. Part I of the study documented ex vivo platelet deposition in 256 ePTFE grafts, 6 cm x 4 mm internal diameter, after ...

Fifteen patients with severe acute vascular graft rejection (twelve of them steroid-resistant) treated with OKT3 monoclonal antibody (8) or antilymphocyte serum (7) were sequentially studied with duplex-Doppler ultrasonography (DDUS). Measurements of intrarenal resistance were obtained by means of the resistive index (RI). During rejection episodes, the intrarenal resistance was increased ...

Cerebral blood flow was measured using [14C]iodoantipyrine quantitative autoradiography in rats which had previously undergone unilateral ibotenate-induced nucleus basalis lesion followed by intracortical implantation of foetal basal forebrain cell suspensions. Transplants had no effect upon host cortical blood flow, although within the transplant itself, blood flow was significantly lower than ...

A double-blind, randomised, placebo-controlled trial was conducted to study the effect of the stable prostacyclin analogue iloprost on femoro-distal graft blood flow. After completing femoro-distal reconstruction, 3000 ng of iloprost or placebo was injected into the graft over 2 min. Graft blood flow, measured by electromagnetic flowmetry, increased by a ...

This study describes our experience using an improved technique for microsurgical sleeve anastomosis of arteries. Modifications of previously described techniques include utilization of a sidecut and placement of the two stitches within separate vertical planes. In 40 arteries, we attained a patency rate of 97.5%. Histology, in vivo observation, and ...

Graft versus host reaction in chicken embryos was induced by blood taken from thymectomized or bursectomized or nonoperated donors. The intensity of graft versus host reaction induced by the blood of thymectomized chickens was increased comparing to the reaction induced by blood from control donors. No such result was recorded ...

We measured surface blood flow in 53 anterior cruciate ligaments (ACLs) reconstructed with allogeneic tendon grafts using laser Doppler flowmetry and examined their histology through biopsy specimens procured during second-look arthroscopy to investigate the fate of ACL allografts on a long-term basis. The age of the grafts, i.e., time from ...

A canine model of occlusive hindlimb venous hypertension was used to determine which of two different, clinically applicable, adjunctive arteriovenous fistulas (AVFs), sequential or peripheral, would augment flow in autogenous cross-femoral venous bypass grafts (CFBs) with the least alteration of hindlimb hemodynamics. Unilateral venous hypertension was produced by iliofemoral venous ...

This study was undertaken to determine the effects of somatostatin 201-995 (SMS) on the maintenance dose of intravenous cyclosporine and on graft blood flow, exocrine secretion, and rejection after porcine pancreaticoduodenal allotransplantation (PDA). For seven days, 12 pigs (6 control, 6 SMS-treated) were studied to determine the effects of SMS ...

We examined intraoperative changes in blood ammonia levels and the correlation with graft viability in orthotopic liver transplantation (OLTx) in 29 dogs. Blood ammonia levels following total hepatectomy were examined using five dogs. These levels immediately following hepatectomy (15 min) were significantly higher (212 +/- 29 micrograms/dl) over values noted ...

This study explores the hemodynamics, mechanics, and biologic response of end-to-end versus end-to-side venous anastomoses in a canine arteriovenous graft model. Femoral polytetrafluoroethylene grafts were implanted bilaterally in a paired fashion (n = 22). Detailed local hemodynamic measurements were made by use of color Doppler ultrasound imaging at 1, 4, ...

Total gastrectomy and oesophagojejunostomy with linear stapling devices were performed on 22 pigs to evaluate whether intersecting staple lines reduce the blood flow with an increased risk of anastomotic leakage. The blood flow at intersecting staple lines and single row staple lines of the anastomosis was studied with the reference ...