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PubMedDate not supplied

Experimental studies on improved polyester-polyurethane vascular grafts for hemodialysis.

A new poly(ether-urethane) graft (PEUG) was developed. Although this graft had several advantages, it became clear that it also had disadvantages, such as the formation of pseudoaneurysms by repeated puncture. To overcome these problems, the PEUG was modified to add mechanical strength by incorporating knitted polyester fibers. Physical strength tests were done, and it was concluded that the graft was more durable than either PEUG or expanded polytetrafluorethylene. Additional experiments showed that gelatin coated PEUG implanted in dogs facilitated endothelialization of the internal surface and improved its patency, although these observations were too short to draw any definitive conclusions.

Animals↗
PubMed1991

Clinical application of modified polyurethane graft to blood access.

Based on a study of 34 clinical implantations, a porous poly(ether-urethane) graft developed for blood access was evaluated. Although it became clear that the graft has several advantages over expanded polytetrafluoroethylene (E-PTFE), it was also revealed that the occlusion at the anastomotic site was more frequently observed than that with E-PTFE. To improve the patency rate, a small modification of the luminal surface was attempted to give a better anchoring of the neointima. The results so far are better than those with the unmodified graft. However, the number of cases is small and the period of observation is short. More work will be necessary to confirm these preliminary results.

Arteriovenous Shunt, Surgical↗
PubMedDate not supplied

[Allergic contact eczema caused by m-xylylene-diamine in the polyurethane silk production].

We found m-xylylene diamine, a widespread additive in plastics, to be a very potent sensitizer. Patch tests with other diamines revealed in all four patients allergic cross reactions to benzylamine. Two persons had also acquired an additional allergy to ethylenediamine. In a 59-year-old man, the allergic contact dermatitis provoked the first manifestation of an atopic dermatitis.

Adolescent↗
PubMed1990

The kinetics and quantitation of platelet deposition on control (CPC) and heparin-bonded polyurethane angio-catheter (HBPC) with indium-111 labeled platelets in a dog model.

The dynamics of platelet deposition on CPC and HBPC was evaluated with In-111 labeled platelets (In-PLT) with a computerized gamma camera (CGC). Ten non-heparinized dogs (18-25 kg) were catheterized in both femoral arteries with 10 cm of CPC and HBPC (5 Fr., Cordis, Inc.) 24 hours post-injection of 300-420 microcuries of In-PLT, and imaged for 3 hours with gamma camera. The regional platelet deposition on three segments of catheters and puncture site was determined. The catheters were harvested and radioactivity on the catheter segments (proximal: PROX, middle: MID, distal: DIST and puncture site: PS) of both was determined. From the platelet count in blood, radioactivity in blood and segments of catheters, adjacent artery and area of artery and catheter, the platelet-density [X10(3)] (mean +/- S.D.) on catheter and artery were calculated and tabulated: (table; see text) The large standard deviation of retained platelets is due to embolization. The platelet-density and regional counts on catheter segments were lower in the HBPC than CPC. The rate of platelet-deposition was lower in the HBPC than CPC. Most of the thrombi were lost during pullout of the catheter. Both in vivo (dynamic) and in vitro studies were necessary for evaluation of CPC thrombogenicity.

Animals↗
PubMedDate not supplied

[Interaction of block-polyurethane containing lactose linkages and immobilized beta-galactosidase with body tissues].

Biodegradation of the polymeric composition containing immobilized beta-galactosidase after implantation and its effect on the surrounding tissues are examined. Immunogenicity of the composition is studied by the method of the immunoenzymic analysis. Activation of the immune system is shown to occur in the process of the composition degradation.

Acid Phosphatase↗
PubMedDate not supplied

Colon cytology simplified using enteric coated encapsulated polyurethane foam as a cellular collecting agent. A preliminary report.

The advantage of the method lies in the relative ease of obtaining cellular material. The patient requires some instruction but need not be medically supervised. The major disadvantage is in fecal contamination and frequently cell preservation that may not be comparable to that of other cytologic approaches. The success of the test depends upon harvesting mucus. It is essential that the laxative action be as mild as possible and that after the initial clearing of the colon an adequate rest period is allowed to permit adequate mucus regeneration.

Colon↗
PubMedDate not supplied

A two year study of the performance of a small diameter polyurethane (Biomer) arterial prosthesis.

The performance of a new compliant microfibrous polyetherurethane urea (Biomer) synthetic artery of our design has been studied in a series of 26 consecutive implants as carotid artery replacements in dogs. A 4 cm length of carotid artery was excised and replaced by a similar length of the synthetic artery. All implants were performed by the same surgeon (LdeC). Twelve interrupted sutures of 6/0 "Prolene" were used to fashion both end-to-end anastomoses. Assessments of patency of the grafts was made using fortnightly Toshiba B scan ultrasound with linked Doppler shift waveform analysis. Twenty-six grafts were implanted. Seventeen grafts have remained patent for periods in excess of 24 months. Five failed acutely (within 2 weeks), 4 failed between the 59th and 201st day. Sixteen of those grafts that remained patent for more than 24 months have been removed for histopathological examination, which has demonstrated a limited extension of a new intima on to the inner surface of the grafts. The new intima is firmly attached and shows no sign of pseudo-intimal hyperplasia. The inner surface, uncovered by neointima, nevertheless, has extensive endothelial cover. Of practical importance are the excellent handling qualities of the graft. It cuts cleanly without fraying and a stitch placed 1 mm from the cut end of the graft will hold securely. There is no needle hole bleeding. The graft has both axial and circumferential compliance similar to that of the natural artery it replaces.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗