The aim of the present study was to detect the transmission rate of ultrasonic low intensity pulsed ultrasound (LIPUS) through polytetrafluoroethylene (PTFE) membrane (Thickness: 0.01 mm) and Bio-Gide collagen membrane, and to provide the basis for the barrier membrane selection on the study of LIPUS combined with guided tissue regeneration (GTR). The ultrasonic (LIPUS, frequency 1.5 MHz, pulse width 200 micros, repetition rate 1.0 kHz) transmission coefficient of the two kinds of barrier membrane were detected respectively through setting ten groups from 10 to 100mW/cm2 every other 10 mW/cm2. We found in the study that the ultrasonic transmission coefficient through 0.01 mm PTFE membrane was 78.1% to 92.%, and the ultrasonic transmission coefficient through Bio-Gide collagen membrane was 43.9% to 55.8%. The ultrasonic transmission coefficient through PTFE membrane was obviously higher than that through Bio-Gide collagen membrane. The transmission coefficient of the same barrier membrane of the ultrasonic ion was statistically different under different powers (P < 0.05). The results showed that the ultrasonic transmittance rates through both the 0.01 mm PTFE membrane and Bio-Gide collagen membrane were relatively high. We should select barrier membranes based on different experimental needs, and exercise ultrasonic transmission coefficient experiments to ensure effective power.
Biocompatible Materials ; Collagen ; chemistry ; Membranes, Artificial ; Permeability ; Polytetrafluoroethylene ; chemistry ; Ultrasonics

OBJECTIVETo study the durability of expanded polytetrafluoroethylene artificial heart valve (ePTFE AHV).

METHODSSix ePTFE AHVs were tested for 400 million times against accelerated fatigue using TH-2200 artificial heart valve exosomatic accelerated fatigue instrument. Hydromechanical parameters of fore-and-aft accelerated fatigue test of the 6 AHVs were obtained by TH-1200 artificial heart valve exosomatic pulsatile stream instrument.

RESULTS AND CONCLUSIONThe mean gradient pressure spanning the valve and the effective orific area of ePTFE AHVs did not undergo significant changes after fore-and-aft the fatigue test, but the regurgitation volume and regurgitation rate of ePTFE AHVs were reduced after the accelerated fatigue test, suggesting good durability of ePTFE AHV.

Biocompatible Materials ; chemistry ; Heart Valve Prosthesis ; standards ; Materials Testing ; methods ; Polytetrafluoroethylene ; chemistry ; Tensile Strength

Guided bone regeneration (GBR) is a technique utilizing membrane as a physical barrier to separate and create a secluded space around the bone defect. This permits the regeneration of bone tissue and reduces the fast growth of connective tissues. Moreover, GBR membranes sustain a protected space during tissue-healing period. Nowadays there are many kinds of GBR membranes used in study and practice, and each of them has its characteristic merits and defects respectively. This paper reviews the studies of GBR membranes, with the emphases on the structure and properties of membrane materials as well as their biological functions.
Biocompatible Materials ; Guided Tissue Regeneration ; methods ; trends ; Humans ; Membranes, Artificial ; Polytetrafluoroethylene ; chemistry ; Silicone Gels ; chemistry ; Tissue Engineering ; methods ; Titanium ; chemistry

OBJECTIVETo evaluate the hemocompatibility of a small-caliber expanded polytetrafluoroethylene vessel with silk fibroin coating sulfonated by low temperature plasma treatment.

METHODSThe composite blood vessel was prepared by first coating the small-caliber expanded polytetrafluoroethylene vessel with silk fibroin followed by sulfonation by low temperature plasma treatment. After hemolysis test in vitro, dynamic coagulation time test, blood platelet adhesion test, and recalcification time test were performed to evaluate the hemocompatibility of the composite blood vessel.

RESULTSScanning electronic microscopy revealed obvious platelets adhesion on the conventional artificial (control) vessel, which seldom occurred on the composite vessel. The curve of absorbance-clotting time of the composite vessel declined more slowly than that of the control vessel. The recalcification time of the composite blood vessel averaged 603 s, significantly longer than that of the control vessel (480 s, P = 0.000).

CONCLUSIONThe composite blood vessel has good antithrombotic activity and hemocompatibility as a promising vascular prosthesis.

Blood Vessel Prosthesis ; Coated Materials, Biocompatible ; chemistry ; Cold Temperature ; Fibroins ; chemistry ; Humans ; Materials Testing ; Plasma Gases ; Polytetrafluoroethylene ; chemistry ; Sulfonic Acids ; chemistry

BACKGROUNDMesh reconstruction has been proved to be an effective method in incisional hernia repairment. This study was designed to evaluate the effect of reconstructing the pelvic floor with the high-inlay expanded polytetrafluoroethylene (ePTFE) GORE-TEX Dual Mesh (WLGore And Associates, Flagstuff, USA) in abdominoperineal resection.

METHODSSixty patients who underwent abdominoperineal resection for rectal cancer were assigned to 2 groups. The pelvic peritoneum was closed by routine sutures in group 1 and reconstructed with ePTFE in group 2. Postoperative complications and related items were evaluated and the patients were followed up.

RESULTSTime of confining to bed, bowel function recovery, fasting, and detaining drainage were significantly different between two groups (P < 0.05). In group 1, three patients developed bowel obstruction (10%), while no bowel obstruction was observed in group 2.

CONCLUSIONReconstruction of the pelvic floor using ePTFE results in quicker postoperative recovery and could decrease the risk of postoperative intestinal obstruction.

Female ; Humans ; Male ; Middle Aged ; Pelvic Floor ; surgery ; Polytetrafluoroethylene ; chemistry ; Postoperative Complications ; Prospective Studies ; Surgical Mesh ; Treatment Outcome

Aged ; Angioplasty, Balloon, Coronary ; adverse effects ; Coronary Vessels ; injuries ; Drug-Eluting Stents ; Humans ; Male ; Polytetrafluoroethylene ; chemistry ; therapeutic use

OBJECTIVETo investigate whether vascular endothelial growth factor (VEGF) gene plasmid carried by polytetrafluoroethylene (PTFE) vascular graft materials could transfect endothelial cells (ECs) and promote their growth.

METHODSPTFE vascular graft materials carried with pCDI-hVEGF(121), pCDI or pEGFP were incubated in Tris-buffer solution and the values of optical density of 260 nm at different time were plotted, then the DNA controlled release curve was made. ECs derived from human umbilical vein were seeded on the pCDI-hVEGF(121)/pCDI/pEGFP-PTFE materials or tissue culture plates, ECs numbers were counted and VEGF protein concentrations at different time were measured by enzyme-linked immunoadsorbent assay method. Green fluorescent protein (GFP) expression in ECs on pEGFP-PTFE materials was examined with fluorescence microscopy.

RESULTSThe controlled release curve showed that the gene released from PTFE materials was rapid within 8 h, then slowed down and that the gene released continuously even after 72 h. At 24, 72 and 120 h, ECs number and proliferation rate of pCDI-hVEGF(121)-PTFE materials were higher than those of pCDI or pEGFP-PTFE materials (P<0.05). VEGF protein concentration of pCDI-hVEGF(121)-PTFE materials was higher than that of pCDI or pEGFP-PTFE materials at 6, 24, 72 and 120 h (P<0.01). GFP expression in ECs on the pEGFP-PTFE materials could be detected by fluorescence microscopy.

CONCLUSIONPTFE graft can be used as a carrier of VEGF gene plasmid, VEGF gene carried by PTFE can transfect ECs and promote ECs growth.

Blood Vessel Prosthesis ; Cell Adhesion ; physiology ; Cell Growth Processes ; physiology ; DNA ; chemistry ; genetics ; Endothelial Cells ; cytology ; physiology ; Humans ; Plasmids ; chemistry ; genetics ; Polytetrafluoroethylene ; Transfection ; methods ; Vascular Endothelial Growth Factor A ; genetics

We investigated tissue responses to endoskeleton stent grafts for saccular abdominal aortic aneurysms (AAAs) in canines. Saccular AAAs were made with Dacron patch in 8 dogs, and were excluded by endoskeleton stent grafts composed of nitinol stent and expanded polytetrafluoroethylene graft. Animals were sacrificed at 2 months (Group 1; n = 3) or 6 months (Group 2; n = 5) after the placement, respectively. The aortas embedding stent grafts were excised en bloc for gross inspection and sliced at 5 to 8 mm intervals for histopathologic evaluation. Stent grafts were patent in all except a dog showing a thrombotic occlusion in Group 2. In the 7 dogs with patent lumen, the graft overhanging the saccular aneurysm was covered by thick or thin thrombi with no endothelial layer, and the graft over the aortic wall was completely covered by neointima with an endothelial layer. Transgraft cell migration was less active at an aneurysm than at adjacent normal aorta. In conclusion, endoskeleton stent grafts over saccular aneurysms show no endothelial coverage and poor transgraft cell migration in a canine model.
Alloys/chemistry ; Angiography ; Animals ; Aortic Aneurysm, Abdominal/*pathology/surgery/ultrasonography ; Cell Movement ; Disease Models, Animal ; Dogs ; Endothelial Cells/cytology ; Neointima/etiology ; Polytetrafluoroethylene/chemistry ; *Stents ; Thrombosis/etiology ; Tomography, X-Ray Computed

OBJECTIVETo investigate the feasibility of vascular graft material polytetrafluoroethylene (PTFE) as gene carrier of vascular endothelial growth factor (VEGF).

METHODSThe PTFE strips were soaked in pCDI-hVEGF(121) solution,marked with EB solution, and then observed under ultraviolet light. The PTFE strips carrying pCDI-hVEGF(121) were soaked in normal saline and the value of optical density at 260 nm on different time was measured, then the controlled release curve was made. The PTFE strips carrying pCDI-hVEGF(121) were implanted into the left thigh muscles of rabbits and the PTFE strips without VEGF gene were implanted into the right. The expression of VEGF(121) mRNA versus beta-actin mRNA in muscles around vascular graft materials was evaluated by reverse transcriptase polymerase chain reaction(RT-PCR). The expression of VEGF(121) protein in muscle was determined by Western blot method.

RESULTThe fluorescence on PTFE strips carrying pCDI-hVEGF(121) was observed under ultraviolet light. The controlled release curve demonstrated that the gene release was fast during 0.5 -4 h, then slowed down afterwards,and lasted for 72 h. RT-PCR and Western blot showed VEGF(121)/beta-actin mRNA ratios were 1.053+/-0.356,1. 718+/-0.404, 2.021+/-0.303, 1.872+/-0.231, 0.986+/-0.254, 0.340+/-0.116 and VEGF(121)protein expression levels were 0.328+/-0.088, 1.019+/-0.105, 2.249 +/-0.203, 2.036+/-0.079, 1.670+/-0.132, 0.636+/-0.107 at 1, 7, 14, 28, 42, and 56 days after implantation, respectively.

CONCLUSIONThe PTFE graft can be used as carrier of VEGF gene and VEGF gene can be transferred to skeletal muscle by this method.

Animals ; Blotting, Western ; Feasibility Studies ; Gene Expression ; Implants, Experimental ; Plasmids ; chemistry ; genetics ; Polytetrafluoroethylene ; chemistry ; RNA, Messenger ; genetics ; metabolism ; Rabbits ; Reverse Transcriptase Polymerase Chain Reaction ; Transfection ; methods ; Vascular Endothelial Growth Factor A ; genetics ; metabolism

OBJECTIVETo test 25# and 27# ultramicroporous expanded polytetrafluo-roethylene mitral valve (UPMV) under pulsatile flow condition in vitro.

METHODSSix 25# and six 27#UPMV were tested using TH-1200 HV Prosthesis Pulsatile Flow Tester in vitro at the cycling rate of 70 cycle/min, with the systolic pressure maintained at about 16 kPa (120 mmHg), diastolic pressure at 10.7 kPa (80 mmHg), and the percentage of mean forward flow at 35%. The stimulant cardiac output was maintained at 2, 3, 4, 5 and 6 L/min, respectively, for the testing.

RESULTSThe mean pressure difference for the 25#UPMV under stimulant cardiac output of 2, 3, 4, 5 and 6 L/min was 2.488-/+0.378, 4.427-/+0.240, 5.460-/+0.449, 6.776-/+0.391 and 8.327-/+0.490 mmHg, and its effective valvular orifice was 1.430-/+0.333, 1.993-/+0.208, 2.260-/+0.477, 3.204-/+0.174 and 3.652-/+0.158 cm(2), respectively. The regurgitant fraction of the 25#UPMV under each stimulant cardiac output was (5.731-/+0.643) %, (5.431-/+0.312) %, (5.059-/+0.708) %, (3.545-/+0.097) % and (2.615-/+0.125) %, respectively. The mean pressure difference of the 27#UPMV under each stimulant cardiac output was 1.618-/+0.497, 3.448-/+0.440, 4.825-/+0.434, 5.494-/+0.446 and 7.482-/+0.455 mmHg, effective valvular orifice was 1.773-/+0.364, 2.113-/+0.305, 2.409-/+0.295, 3.326-/+0.417 and 4.522-/+0.445 cm(2), and regurgitant fraction was (5.357-/+0.509) %, (5.407-/+0.110) %, (4.999-/+0.182) %, (4.010-/+0.254) % and (2.584-/+0.114)%, respectively.

CONCLUSIONThe mean pressure difference, effective valvular orifice and regurgitant fraction of the UPMVs can measure up to the national criteria for artificial heart valve prosthesis of China.

Biocompatible Materials ; chemistry ; Cardiac Output ; Heart Valve Prosthesis ; standards ; Heart Valve Prosthesis Implantation ; methods ; Heart-Assist Devices ; standards ; Humans ; Materials Testing ; methods ; Mitral Valve ; Polytetrafluoroethylene ; chemistry ; Porosity ; Pulsatile Flow