Dacron Fabric Research Articles

Role of biofilm in Staphylococcus aureus and Staphylococcus epidermidis ventricular assist device driveline infections

Infections, especially those involving drivelines, are among the most serious complications that follow ventricular assist device implantation. Staphylococci are the most common causes of these infections. Once driveline infections are established, they can remain localized or progress as an ascending infection to cause metastatic seeding of other tissue sites. Although elaboration of biofilm appears to be critical in prosthetic device infections, its role as a facilitator of staphylococcal infection and migration along the driveline and other prosthetic devices is unclear. A murine model of driveline infection was used to investigate staphylococcal migration along the driveline. A biofilm-producing strain of Staphylococcus epidermidis and a Staphylococcus aureus strain and its intercellular adhesion gene cluster (ica)-negative (biofilm-deficient) isogenic mutant were used in these studies. Bacterial density on the driveline and the underlying tissue was measured over time. Scanning electron microscopy was used to examine the morphology of S epidermidis biofilm formation as the infection progressed. The biofilm-deficient S aureus mutant was less effective at infecting and migrating along the driveline than the wild-type strain over time. However, the ica mutation had no effect on the ability of the strain to infect underlying tissue. S aureus exhibited more rapid migration than S epidermidis. Scanning electron microscopy revealed the deposition of host matrix on the Dacron material after implantation. This was followed by elaboration of a bacterial biofilm that correlated with more rapid migration along the driveline. Biofilm formation is a critical virulence determinant that facilitates the progression of drivelines infections.

Early stenosis of Medtronic Mosaic porcine valves in the aortic position

The third-generation Medtronic Mosaic porcine bioprosthesis (Medtronic Inc, Minneapolis, Minn) was introduced in 1994. The valve leaflets are fixed in glutaraldehyde at zero pressure (applying equal pressure to the inflow and outflow ends of the valve), the root is dilated to a pressure of 40 mm Hg (“physiologic fixation”), the fixed tissue is treated with α-aminooleic acid (a long-chain fatty acid that binds to the aldehyde fractions of the glutaraldehyde-preserved porcine tissue) to reduce calcification, and the tissue is mounted on a Hancock II (Medtronic Inc) flexible stent made of acetyl copolymer covered with Dacron fabric.

Wall rupture of Medtronic Freestyle stentless porcine aortic root bioprosthesis

The Medtronic Freestyle stentless bioprosthetic valve provides excellent hemodynamics and long-term durability. However, several studies have reported mid-term structural valve deterioration unique to cases of Freestyle bioprosthesis implantation. According to these reports, the degeneration of the porcine aortic wall causes the dilatation and disruption of the sinus of Valsalva. We encountered a very rare case of an 8 mm-long tear located just above the inflow end of the Dacron cloth. The sudden rupture of the bioprosthetic aortic wall formed a pseudoaneurysm that compressed and almost occluded the pulmonary artery leading to low cardiac output syndrome and shock.

Commissural dehiscence: A rare and peculiar cause of porcine valve structural deterioration

Calcification is the main cause of structural valve deterioration; however, other causes of failure have been identified, and among them, dehiscence of a commissure from the stent has been reported in several models of porcine valves. The aim of this study was to analyze the rate and mode of occurrence of this complication in first- and second-generation porcine bioprosthetic explants. Among 586 porcine xenografts explanted and analyzed at the Institute of Pathological Anatomy of the University of Padua, 17 (2.9%) have been replaced for incompetence because of commissural dehiscence. All these explants were in the mitral position, with the exception of a Carpentier-Edwards supra-annular aortic valve prosthesis. Dehiscence was observed in 9 (1.9%) of 455 Hancock standard explants, in 1 (3.2%) of 31 Hancock II, in 3 (8.6%, 2 standard and 1 supra-annular) of 35 Carpentier-Edwards, in 1 (2.4%) of 42 Bioimplants, and in 3 (50%) of 6 Xenotech after a mean time function of 157 +/- 50, 156, 96 +/- 29, 143, and 130 +/- 8 months, respectively. Dehiscence was the sole cause of incompetence in 6 cases. An impending commissural dehiscence caused by blood creeping was observed in one case. This might be an explanation for the dehiscence other than excessive trimming of the aortic wall. Commissural dehiscence is an uncommon and peculiar mode of failure of porcine valves implanted in the mitral position and was observed earlier and more frequently with Carpentier-Edwards porcine explants (P < .05). We speculate that pericardial strip protection of the suture between the Dacron fabric and porcine aortic wall, as used in the Biocor porcine valve, might prevent this complication.

A Case of 24 Years Longevity of an Ionescu-Shiley Bioprosthesis in the Mitral Position

Valve dysfunction, attributed to primary tissue failure several years after implantation of Ionescu-Shiley bioprostheses, has led to re-operation in most cases. We report a rare case of this bioprosthesis showing stenosis and regurgitation after implantation in the mitral position 24 years previously. No cusp tears, but severe calcification and well-grown neointima over the Dacron cloth of the inner surface were observed. This may explain how the valve functioned for such a long period of time. We replaced it with a Carpentier-Edwards pericardial bioprosthesis.

Surgical treatment of jugular vein phlebectasia in children

Background Jugular vein phlebectasia (JVP) is a cervical mass that occurs relatively infrequently and usually presents in children as a soft cystic swelling in the neck during straining. It is liable to be misdiagnosed or managed inappropriately. This report elucidates the clinical presentation, diagnosis, treatment choices, and postoperative complications of JVP, and diagnostic methods and treatment choices are recommended. Methods Fifty-one cases of JVP were reviewed (right vein in 38 patients, left in 7 patients, and bilateral in 6 patients). The internal jugular vein was involved the most frequently. The main complaint was a soft and compressible mass in the neck, becoming more prominent with the Valsalva maneuver. All of the children except 2 had an ultrasound or color Doppler flow imaging (CDFI) performed in combination with the Valsalva’s breathing test. Surgical intervention was performed in 46 patients and the other 5 patients were followed-up conservatively for 2 to 15 years. Results Ultrasound or CDFI showed local dilatation of unilateral or bilateral veins in all patients except 2, and confirmed the diagnosis in combination with the Valsalva’s breathing test. Surgical intervention included ligation of the involved jugular vein in 32 patients, and longitudinal constriction suture venoplasty plus encapsulation with medical Dacron cloth or PTFE in 14 patients. All of the children who had surgery recovered uneventfully, except 3 patients undergoing ligation of the right internal jugular vein. Conclusions The Valsalva maneuver was most important for establishing the diagnosis. Ultrasound or CDFI, or in combination with the Valsalva’s breathing test, was the diagnostic procedure of choice to confirm the diagnosis of JVP because of its clarity, safety, and low cost. Surgical intervention was recommended for cosmetic and psychologic purposes. Ligation or excision of the involved jugular vein was very safe, simple, and effective for most patients. However, in cases of lesions of the right and bilateral internal jugular veins, longitudinal constriction suture venoplasty plus encapsulation might be more preferable and safer, and should be recommended. Otherwise, treatment should be conservative (follow-up evaluation).

The Use of Extracellular Matrix as an Inductive Scaffold for the Partial Replacement of Functional Myocardium

Regenerative medicine approaches for the treatment of damaged or missing myocardial tissue include cell-based therapies, scaffold-based therapies, and/or the use of specific growth factors and cytokines. The present study evaluated the ability of extracellular matrix (ECM) derived from porcine urinary bladder to serve as an inductive scaffold for myocardial repair. ECM scaffolds have been shown to support constructive remodeling of other tissue types including the lower urinary tract, the dermis, the esophagus, and dura mater by mechanisms that include the recruitment of bone marrow-derived progenitor cells, angiogenesis, and the generation of bioactive molecules that result from degradation of the ECM. ECM derived from the urinary bladder matrix, identified as UBM, was configured as a single layer sheet and used as a biologic scaffold for a surgically created 2 cm2 full-thickness defect in the right ventricular free wall. Sixteen dogs were divided into two equal groups of eight each. The defect in one group was repaired with a UBM scaffold and the defect in the second group was repaired with a Dacron patch. Each group was divided into two equal subgroups (n = 4), one of which was sacrificed 15 min after surgical repair and the other of which was sacrificed after 8 weeks. Global right ventricular contractility was similar in all four subgroups groups at the time of sacrifice. However, 8 weeks after implantation the UBM-treated defect area showed significantly greater (p < 0.05) regional systolic contraction compared to the myocardial defects repaired with by Dacron (3.3 +/- 1.3% vs. -1.8 +/- 1.1%; respectively). Unlike the Dacron-repaired region, the UBM-repaired region showed an increase in systolic contraction over the 8-week implantation period (-4.2 +/- 1.7% at the time of implantation vs. 3.3 +/- 1.3% at 8 weeks). Histological analysis showed the expected fibrotic reaction surrounding the embedded Dacron material with no evidence for myocardial regeneration. Histologic examination of the UBM scaffold site showed cardiomyocytes accounting for approximately 30% of the remodeled tissue. The cardiomyocytes were arranged in an apparently randomly dispersed pattern throughout the entire tissue specimen and stained positive for alpha- sarcomeric actinin and Connexin 43. The thickness of the UBM graft site increased greatly from the time of implantation to the 8-week sacrifice time point when it was approximately the thickness of the normal right ventricular wall. Histologic examination suggested complete degradation of the originally implanted ECM scaffold and replacement by host tissues. We conclude that UBM facilitates a constructive remodeling of myocardial tissue when used as replacement scaffold for excisional defects.

Endovascular Repair of Nontraumatic Ruptured Thoracic Aortic Pathologies

Endovascular repair of ruptured infrarenal abdominal aortic aneurysms (AAA) is receiving increased attention as the number of experienced users increases. Development of thoracic aortic stent grafts has lagged behind infrarenal advancements because of the reported prevalence of disease. In a few centers, however, the experience in performing thoracic stent graft procedures is quite substantial, such that endovascular therapy has been applied to ruptured thoracic aortic pathologies even though data remain limited and this novel therapy remains controversial. We report our combined experience with endovascular repair of ruptured thoracic aneurysms (RTA) and ruptured thoracic dissections (RTD). One hundred eighty-four thoracic stent graft procedures at the University of North Carolina (UNC) and Union Memorial Hospital (UMH) were reviewed and those patients undergoing RTA or RTD repair from January 1, 2000 to December 31, 2003 identified. Patients having procedures for elective repair or aortic transections were excluded from the analysis. Patient presentation, preoperative condition, procedural variables, mortality, and morbidity were examined. Seventy-four percent of the collective procedures were undertaken in high-risk patients (UNC, 38 of 40; UMH, 99 of 144). Twenty-two patients (8.7%; UNC, n = 6; UMH, n = 16) underwent treatment for either an RTA (n = 11) or an RTD (n = 11). The average age of this cohort was 66.5 ± 15.6 years and the average aneurysm diameter was 73.1 ± 31.4 mm. The mean duration of symptoms prior to repair was 103.1 ± 122 hr, influenced primarily by transport times and device availability. Stent graft exclusion was accomplished in 100% of patients with a procedural mortality of 0%. Commercial Talent devices were used in 19 patients (86.4%) and AneuRx device was used in 1 patient (4.5%). In the remaining two (9.1%) patients handmade devices constructed of Gianturco stents and Dacron fabric were used because of active hemorrhage and lack of appropriate device sizes. Operative time was 135.5 ± 48.5 min and was associated with an average blood loss of 242.0 ± 232.4 cc. Thirty-day mortality was 45.5% (RTA, 27.3%; RTD, 63.6%; p = 0.099). Length of stay in the intensive care unit was 6.1 ± 7.9 days and the mean hospital stay was 11.7 ± 10.6 days. Major complications were present in 54.5% of RTA (cardiac, 1; pulmonary, 3; cardiovascular accident, 2; spinal cord ischemia, 2; pulmonary embolism, 1), and 81.2% of RTD (multisystem organ failure, 7; pulmonary, 1; common femoral artery injury, 1) but not statistically different between groups. There were only two late complications (cardiac death, endoleak-Ia, 1) that occurred during the mean follow-up of 12.5 ± 11.3 (range, 1-32) months. These results indicate that endovascular repair of ruptured thoracic pathologies can be accomplished with an acceptable morbidity and mortality. There were no immediate procedural mortalities and complete exclusion was accomplished in all patients. Most postoperative complications arose from preexisting medical conditions and were not procedure related. The benefit of endovascular repair of ruptured thoracic aortic pathologies is promising.

Development of an infection‐resistant, bioactive wound dressing surface

Trauma, whether caused by an accident or in an intentional manner, results in significant morbidity and mortality. The goal of this study was to develop a novel biomaterial surface in vitro and ex vivo that provides both localized infection resistance nd hemostatic properties. Our hypothesis is that a combination of specific surface characteristics can be successfully incorporated into a single biomaterial. Functional groups were created with woven Dacron (Cntrl) material via exposure to ethylenediamine (C-EDA). The antibiotic ciprofloxacin (Cipro) was then applied to the C-EDA material using pad/autoclave technique (C-EDA-AB) followed by surface immobilization of the coagulation cascade enzyme thrombin (C-EDA-AB-Thrombin). Antimicrobial activity by the C-EDA-AB surface persisted for 5 days compared with Cntrl and dipped controls, which lasted <1 h. C-EDA-AB-Thrombin surfaces had 2.6- and 105-fold greater surface thrombin activity compared with nonspecifically bound thrombin and Cipro-dyed surfaces, respectively. Surface thrombus formation ex vivo was evident after 1 min of exposure, with thrombus organization evident by 2.5 min. In contrast, C-EDA-AB and Cntrl segments showed only blood protein adsorption on the fibers. Thus, this study demonstrated that Cipro and thrombin can be simultaneously incorporated onto a biomaterial surface while maintaining their respective biological activities.

Congenital jugular vein phlebectasia

Background/purpose The purpose of the present study was to elucidate the clinical presentation, diagnosis, treatment, and postoperative complications of jugular vein phlebectasia (JVP), and to recommend diagnostic methods and treatment choices. Materials and methods Thirty-six cases of JVP were reviewed (right vein in 27, left in 6, and bilateral in 3). The internal jugular veins were the most commonly involved. The main complaint was the soft and compressible mass in the neck. Ultrasound or color Doppler flow imaging (CDFI) was performed on all the children. Surgical intervention was performed in 32 cases, and the other 4 cases were conservatively followed up for 4 to 6 years. Results Ultrasound or CDFI demonstrated local dilatation of the unilateral or bilateral veins in all the patients. Surgical intervention included ligation of the involved jugular vein in 31 cases and draping with medical Dacron cloth in 1 case. All of the operated children recovered uneventfully, except 3 for cases who underwent ligation of the right internal jugular vein. Conclusions Valsalva maneuver was most important for establishing the diagnosis. Ultrasound or CDFI was the diagnostic procedure of choice to confirm the diagnosis of JVP. Surgical ligation or excision of unilateral jugular vein was recommended for cosmetic and psychological purposes. However, special attention must be paid to prevent postoperative complications in case of ligation of right internal jugular vein. Or else, treatment should be conservative (follow-up).

Endovascular Repair of Nontraumatic Ruptured Thoracic Aortic Pathologies

Endovascular repair of ruptured infrarenal abdominal aortic aneurysms (AAA) is receiving increased attention as the number of experienced users increases. Development of thoracic aortic stent grafts has lagged behind infrarenal advancements because of the reported prevalence of disease. In a few centers, however, the experience in performing thoracic stent graft procedures is quite substantial, such that endovascular therapy has been applied to ruptured thoracic aortic pathologies even though data remain limited and this novel therapy remains controversial. We report our combined experience with endovascular repair of ruptured thoracic aneurysms (RTA) and ruptured thoracic dissections (RTD). One hundred eighty-four thoracic stent graft procedures at the University of North Carolina (UNC) and Union Memorial Hospital (UMH) were reviewed and those patients undergoing RTA or RTD repair from January 1, 2000 to December 31, 2003 identified. Patients having procedures for elective repair or aortic transections were excluded from the analysis. Patient presentation, preoperative condition, procedural variables, mortality, and morbidity were examined. Seventy-four percent of the collective procedures were undertaken in high-risk patients (UNC, 38 of 40; UMH, 99 of 144). Twenty-two patients (8.7%; UNC, n = 6; UMH, n = 16) underwent treatment for either an RTA (n = 11) or an RTD (n = 11). The average age of this cohort was 66.5 +/- 15.6 years and the average aneurysm diameter was 73.1 +/- 31.4 mm. The mean duration of symptoms prior to repair was 103.1 +/- 122 hr, influenced primarily by transport times and device availability. Stent graft exclusion was accomplished in 100% of patients with a procedural mortality of 0%. Commercial Talent devices were used in 19 patients (86.4%) and AneuRx device was used in 1 patient (4.5%). In the remaining two (9.1%) patients hand-made devices constructed of Gianturco stents and Dacron fabric were used because of active hemorrhage and lack of appropriate device sizes. Operative time was 135.5 +/- 48.5 min and was associated with an average blood loss of 242.0 +/- 232.4 cc. Thirty-day mortality was 45.5% (RTA, 27.3%; RTD, 63.6%; p = 0.099). Length of stay in the intensive care unit was 6.1 +/- 7.9 days and the mean hospital stay was 11.7 +/- 10.6 days. Major complications were present in 54.5% of RTA (cardiac, 1; pulmonary, 3; cardiovascular accident, 2; spinal cord ischemia, 2; pulmonary embolism, 1), and 81.2% of RTD (multisystem organ failure, 7; pulmonary, 1; common femoral artery injury, 1) but not statistically different between groups. There were only two late complications (cardiac death, endoleak-Ia, 1) that occurred during the mean follow-up of 12.5 +/- 11.3 (range, 1-32) months. These results indicate that endovascular repair of ruptured thoracic pathologies can be accomplished with an acceptable morbidity and mortality. There were no immediate procedural mortalities and complete exclusion was accomplished in all patients. Most postoperative complications arose from preexisting medical conditions and were not procedure related. The benefit of endovascular repair of ruptured thoracic aortic pathologies is promising.

Laparascopic aortic reinforcement and endovascular graft replacement

Purpose. The purpose of this study is to evaluate the feasibility of using an external aortic wrap in conjunction with an endovascular graft and to examine the histological response. Methods. Six female pigs, 56–84 kg, underwent laparoscopic retroperitoneal placement of homemade aortic wraps made of Dacron fabric and specially designed straps just below the renal arteries. One week later, stents (one 12 mm × 4 cm Wallstent, two 308 Palmaz stents) were inserted into the infrarenal aorta for preliminary experiments in three pigs, and stent-grafts (13 mm × 5 cm Viabahn) were placed in three pigs. The stents and stent-grafts were aligned with the proximal edge of the aortic wrap, and the balloon was expanded. One animal was prematurely sacrificed. The pigs were followed for 1 to 3 weeks in stent models and for 4 weeks in stent-graft models. The animals were then sacrificed, and abdominal aortas were harvested for histological examination. Results. Technical success was achieved in all animals without complications. One animal was prematurely sacrificed due to cerebral edema secondary to anesthesia. Laparoscopic operative time was 2:42 ± 0:47, and 0:43 ± 0:15 for stent placement. Gross examination of the samples revealed fibrosis external to the device at 1- and 3-week time-points; by 3 weeks the wrap was partially incorporated into the adventitia. Stents and stent-grafts were well incorporated into the intima and no migration was observed. Histological examination of all samples revealed a foreign-body response. Sections taken from beneath the device edges revealed necrosis localized to the muscularis and adventitial aortic junction; however, sections taken from beneath the device body showed no signs of necrosis and the vasa vasorum of the aortic wall was intact. Conclusions. Coordinate laparoscopic external aortic wrapping and stent-grafting is feasible in a porcine model. Aortic wall necrosis was limited. This adjunct to endovascular graft repair of abdominal aortic aneurysms may enhance eligibility for patients with large aortic neck and prevent proximal type 1 endoleak.

EFFECTS OF CHITOSAN AND BASIC FIBROBLAST GROWTH FACTOR FOR ANTI-INFECTION OF LVAD DRIVELINE

Purpose: Driveline infection of left ventricular assist device (LVAD) is an unsolved and devastated complication. Chitosan has a disinfective property and ability to accelerate wound healing. Basic fibroblast growth factor (bFGF) accelerates neovascularization and granulation. The purpose of this study is to evaluate the effect of the chitosan and bFCF for anti-infection and wound healing of LVAD driveline. Methods: 4 groups of double velour Dacron fabric (1O×50×1 mm) [Group 1: Chitosan (−), bFCF(−), Group 2: Chitosan (+), bFGF(−), Group 3: Chitosan (−), bFCF(+), Group 4: Chitosan (+), bFGF(+)I were implanted in the subcutaneous layer of calves. Observations were made after 7, 14, and 28 days, the area of granulation around the fabric and the level of migration into the fabric were evaluated. Results: The area of granulation (mm2) for day 7, 14, and 28 were, respectively, in Group 1 (0.291 ±0.087, 0.228±0.058, and 0.304±0.097), Group 2 (0.530±0.101, 0.402±0.270, and 0.47±20.208), Group 3 (0.38±20.074, 0.264±0.043, and 0.254±0.058), Croup 4 (0.464±0.144, 0.322±0.155, and 0.437±0.219). There were significant differences among groups. Chitosan accelerated granulation around the fabric. bFCF accelerated migration of inflammatory cells into the fabric. Consideration: Chitosan and/or bFCF demonstrated potential for preventing LVAD driveline infection.

Abdominal aortic healing associated with a thin-walled Dacron-covered endovascular graft in a canine model.

To characterize the healing response associated with an experimental endovascular graft (EVG) by examining the lumen of the prosthesis and the native vessel wall responses after implantation in a canine model. An endovascular graft (EVG) constructed of hookless self-expanding nitinol springs covered by an ultrathin Dacron fabric was placed in the abdominal aorta of 8 dogs following femoral artery catheterization. After 12 weeks, specimens were subjected to histological and immunocytochemical testing to quantitatively and qualitatively analyze the cellular makeup of the luminal and abluminal tissues. Gross examination revealed a glistening, thrombus-free luminal surface on all prostheses, which was confirmed by scanning electron microscopy. The EVGs were well incorporated into the aortic wall, leaving a concentric, smooth flow surface. Immunocytochemistry verified the presence of von Willebrand factor-positive endothelial cells on the luminal surface and alpha-smooth muscle cell actin-positive smooth muscle and/or fibroblast cells in the subendothelial space. A sparse inflammatory response and a paucity of proliferating nuclear cell antigen-positive cells were noted within the neomedial lining adjacent to the graft material. In addition, a rich vaso vasorum-like plexus of microvessels was evident within the neomedial tissue. The native vessel wall upon which the EVG impinged was largely unaffected. CONCLUSIONS; These data demonstrate that placement of an experimental EVG in the canine abdominal aorta elicits a healing response that is distinct from interpositional vascular grafts. Results from this study have particular relevance to the proximal and distal anastomotic neck regions.

Influence of dacron tissue thickness on the performance of the Pintucci biointegrable keratoprosthesis: an in vitro and in vivo study.

In 1979 Pintucci developed a biointegrable keratoprosthesis with polymethylmethacrylate optical cylinder integrated with a Dacron tissue-colonizable supporting element to avoid the complications caused by the interaction between the haptic element and the eye. The purpose of this article is to compare the colonization of three Dacron fabrics (thicknesses of 0.25 mm, 0.6 mm, and 1.4 mm) in vitro and in vivo to optimize the device performance. In vitro three different Dacron fabrics were cultured for 3 days with 3.5 x 10(5) human fetal lung fibroblasts and observed with a scanning electron microscope. In vivo three different Dacron fabrics were implanted on the sclera near the superior rectus insertion in the right eye of six albino rabbits and were observed after 4 days with light and scanning electron microscopy. In the in vitro experiments, the cells were preserved and their structure was found to be normal. The 0.25-mm thick fabric was coated only on the surface, and the other fabrics were colonized in three dimensions. In the in vivo experiments, the 0.25-mm thick fabric appeared coated only on its surface. The other fabrics were three-dimensionally colonized and the Dacron filaments appeared embedded in neovascularized connective tissue with minimal foreign body reaction. The 1.4-mm thick colonized fabric showed a substantial loss of pliability. Given that the 0.25-mm thick fabric was coated only by connective tissue, that the 0.6-mm and 1.4-mm thick fabrics were perfectly colonized, and that the 1.4-mm thick fabrics showed a substantial loss of pliability, the 0.6-mm thick fabric haptic part of the Pintucci keratoprosthesis is preferred. For 19 years, the 0.6-mm Dacron fabric Pintucci keratoprosthesis was implanted in 159 eyes with good results, overcoming the apparently inseparable difficulties represented by mechanical anchorage and biointegrability of a keratoprosthesis.

Implant technique for the freestyle stentless bioprosthesis

Implant technique for the freestyle stentless bioprosthesis

A New Titanium Fiber Mesh-Cuffed Peritoneal Dialysis Catheter: Evaluation and Comparison with a Dacron-Cuffed Tenckhoff Catheter in Goats

We report the development of a new peritoneal dialysis catheter. The purpose of the current study was to evaluate tissue response to this catheter. In our catheter design, the catheter's cuffs are made from sintered titanium fiber mesh instead of the common Dacron material. The catheters were implanted in goats. During the study period, the catheter exit sites were observed once every 2 weeks. After 14 weeks, the catheters and surrounding tissues were processed for histology and analyzed. We observed that catheters with titanium cuffs performed significantly better, compared with a commercial catheter design. Histology showed that titanium fibers evoked a lesser inflammatory response compared with Dacron fibers. In addition, the capsule surrounding the titanium cuff was significantly thinner. Supported by the obtained results, we conclude that the use of Dacron velour for anchorage of percutaneous catheters has to be reconsidered. Titanium fiber mesh has a great potential for application in percutaneous catheters.

Photocatalytic activity of TiO2prepared at low temperature by a photo-assisted sol-gel method

TiO2nanocrystals were prepared by a photo-assisted sol-gel process in which tetrabutoxide titanate was hydrolyzed in acidic medium under ultraviolet irradiation. X-ray diffraction and Raman spectra showed that the as-prepared TiO2particles without further annealing were well-crystallized anatase. Such TiO2particles were easily immobilized on dacron cloth and showed very high photocatalytic activity. In contrast, TiO2particles were ill crystallized and showed lower activity when no light was introduced under otherwise equal conditions.

Invited commentary

Invited commentary

A combination of wrapping and clipping using a collagen-impregnated Dacron fabric (Hemashield)

BACKGROUND We describe techniques combining wrapping and clipping using a collagen-impregnated Dacron knitted fabric (Hemashield) for accidental arterial perforations and broad-based aneurysms. The results of these techniques in seven patients are presented. METHODS Clip-reinforced wrapping was performed to obtain hemostasis in two patients with arterial perforations and in a patient with a ruptured broad-based aneurysm in the internal carotid artery. Clipping of the broad neck of the aneurysm and wrapping with Hemashield (wrap-clipping) was performed in four patients with unruptured aneurysms (one internal carotid artery, two middle cerebral artery, one basilar artery). RESULTS In the three patients treated with clip-reinforced wrapping, complete hemostasis was obtained just after clip application. In the patient with a ruptured broad-based aneurysm, postoperative angiography demonstrated that the dome of the aneurysm was well compressed. In the four patients treated with wrap-clipping, postoperative angiography revealed successful clipping of the broad neck of the aneurysm. CONCLUSION In this early experience, there were no problems in the use of Hemashield for clip-reinforced wrapping or wrap-clipping.