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PubMed2004

Small-angle X-ray scattering on the ChemMatCARS beamline at the Advanced Photon Source: a study of shear-induced crystallization in polypropylene.

The first ever time-resolved small-angle X-ray scattering (SAXS) data from the undulator 15-ID-D beamline (ChemMatCARS) are presented. A 1.3 A (9.54 keV) X-ray beam was selected to study the structure development in a polypropylene sample during shear-induced crystallization. A Linkam CSS450 shear cell provided the temperature and shear control. The polypropylene was first melted and then quenched to the crystallization temperature, where a step shear was applied. The SAXS data were collected using a Bruker 6000 CCD detector, which provided images of excellent resolution. The SAXS images (with 180 degrees rotational symmetry) indicated that the polypropylene crystallizes with a high degree of anisotropy, and the lamellae are oriented perpendicular to the flow direction.

Crystallization↗
PubMed1976

Testing the effects of fluids on rat skin using disposable polypropylene chambers.

Inexpensive, disposable polypropylene chambers for testing fluids on rat skin were made by removing the wings from polypropylene wing nuts and by cutting into the top of each nut a seat for an O-ring. Polypropylene screws with black heads were fabricated as seals for the chambers. After attachment to the backs of rats, these chambers provided a satisfactory means of keeping fluid in contact with the skin for 3 days.

Animals↗
PubMed2004

Single surgeon experience with bilayer polypropylene mesh repair of inguinal hernia.

BACKGROUND: Open mesh repair of inguinal hernia has been shown to be an effective and safe method of hernia repair. In search of the 'ideal' method of open mesh hernia repair, many different methods of mesh placement have been developed. Laparoscopic hernia repair is reported to be superior to open repair in terms of postoperative pain and rehabilitation. These improved functional outcomes could be the result of placement of mesh in the preperitoneal space (underlay), rather than the laparoscopic method per se. A bilayer polypropylene mesh implant has been developed that provides onlay and underlay (preperitoneal) mesh layers. The present study reports the singular experience of a general surgeon with this bilayer polypropylene mesh implant. METHODS: A retrospective audit of the first 169 consecutive inguinal hernia repairs was conducted by mailed questionnaire and telephone interview. Data was collected on patient demographics, postoperative pain scores and complications. Patients with potential recurrences at the time of follow up were invited for clinical review. RESULTS: One hundred and three patients (71%) participated in the audit. Thirteen per cent of cases were for recurrent hernia. Median age was 60 years (range 21-99). Median length of follow up was 19 months (range 8-27). No recurrences were detected in the patients who underwent primary repair of inguinal hernia. CONCLUSION: Inguinal hernia repair with bilayer polypropylene mesh is safe and has low complication and recurrence rates.

Adult↗
PubMed2005

Inguinal hernia repair with polypropylene mesh during radical retropubic prostatectomy: an easy and practical approach.

OBJECTIVE: To report the results of the simultaneous inguinal hernia repair during radical retropubic prostatectomy (RRP) with the preperitoneal tension-free Stoppa technique, using a polypropylene mesh. PATIENTS AND METHODS: During 855 consecutive RRPs, 40 (5%) patients (median age 66.9 years, range 52-81) with 49 inguinal hernias had a simultaneous inguinal hernioplasty. The RRP was performed according to the Walsh modified technique. After the prostate and seminal vesicles were removed and the urethrovesical anastomosis completed, a polypropylene mesh of maximum size 15 x 7.5 cm and a small slit on its medial side was then created and placed in the preperitoneal space, embracing the spermatic cord and covering the myopectinal orifice. Preoperative risk factors, e.g. constipation, pulmonary disease or urinary obstructive symptoms, were collected retrospectively from the files. Complications after surgery, including wound infection, pelvic collections, urinary fistula and recurrence of the hernia, were assessed. RESULTS: Preoperative risk factors for hernia development were identified in 23 (58%) patients; three had recurrent hernias. With a median 23.1 months of follow-up period two (4%) hernias recurred. There were no complications after surgery. CONCLUSION: Preperitoneal hernia repair with polypropylene mesh is safe, effective and practical. The procedure simultaneous with RRP gave a 96% success rate and with no significant increase in operating time or additional complications.

Aged↗
PubMedDate not supplied

The effects of surgical isolation and application of polypropylene spiral prostheses on tracheal blood flow.

Tracheal blood flow before and after division of the segmental tracheal blood supply with and without application of a polypropylene spiral prosthesis was measured in dogs by radiolabeled microsphere injection. Ischemia of the central part of the trachea, from the mid-cervical to mid-thoracic regions, was observed immediately after division of the segmental tracheal blood supply with and without polypropylene spiral prosthesis application. On day 3, tracheal blood flow was significantly decreased in the central part of the trachea with and without polypropylene spiral prosthesis application. On day 7, tracheal blood flow was significantly increased throughout the trachea, with no significant differences between animals with and without prosthesis application. There was no evidence of a collateral source of blood supply to the trachea. Surgical division of the segmental tracheal blood supply of the trachea. Surgical division of the segmental tracheal blood supply of the entire trachea is not recommended.

Animals↗
PubMed2006

Laparoscopic obliteration of the nephrosplenic space using polypropylene mesh in five horses.

OBJECTIVE: To report a laparoscopic technique for insertion of polypropylene mesh in the nephrosplenic space in horses and evaluate outcome. STUDY DESIGN: Descriptive experimental study. ANIMALS: Five healthy mature horses. METHODS: One laparoscope and 2 instrument portals were made on the left side of the horse. The nephrosplenic space was measured and appropriately sized polypropylene mesh was inserted and attached to the dorsolateral splenic capsule and perirenal fascia using helical titanium coils. All horses had repeat laparoscopy 4 weeks later and were necropsied at intervals 4-14 weeks after mesh placement. RESULTS: Mean time for laparoscopic mesh placement was 104 minutes. None of the horses had signs of colic and at 4 weeks all mesh implants were covered by fibrous tissue. One horse had a descending colon mesenteric adhesion to the mesh. At necropsy, the fibrous tissue covering the mesh had adhered to itself and pulled the splenic capsule and perirenal fascia into close apposition. Each mesh implant was firmly adhered to the spleen, nephrosplenic ligament, and perirenal fascia. CONCLUSIONS: Laparoscopic mesh placement was easily performed, well tolerated, and provided excellent fibrous obliteration of the nephrosplenic space. The single important complication observed was a mesenteric adhesion of the descending colon to the mesh in 1 horse. CLINICAL RELEVANCE: Laparoscopic placement of polypropylene mesh leads to obliteration of the nephrosplenic space within 4 weeks and should prevent entrapment of viscera in the nephrosplenic space.

Animals↗
PubMed1993

Isotactic polypropylene biodegradation by a microbial community: physicochemical characterization of metabolites produced.

From a selective enrichment culture prepared with different soil samples on starch-containing polyethylene we isolated four microaerophilic microbial communities able to grow on this kind of plastic with no additional carbon source. One consortium, designated community 3S, was tested with pure isotactic polypropylene to determine whether the consortium was able to degrade this polymer. Polypropylene strips were incubated for 5 months in a mineral medium containing sodium lactate and glucose in screw-cap bottles. Dichloromethane crude extracts of the cultures revealed that the weight of extracted materials increased with incubation time, while the polypropylene sample weight decreased. The extracted materials were characterized by performing chromatographic and spectral analyses (thin-layer chromatography, liquid chromatography, gas chromatography-mass spectrometry, infrared spectrometry, nuclear magnetic resonance). Three main fractions were detected and analyzed; a mixture of hydrocarbons at different degrees of functionalization was found together with a mixture of aromatic esters, as the plasticizers usually added to polyolefinic structures.

Alcaligenes↗
PubMedDate not supplied

Influence of titanium coating on the biocompatibility of a heavyweight polypropylene mesh. An animal experimental model.

INTRODUCTION: In light of the fact that, to date, no information is available about titanium relative to its application in prosthetic material employed for hernial repair, the aim of the present work was to evaluate the fundamental possibilities of titanium-coated polypropylene meshes. MATERIALS AND METHODS: In experiments with animals, two groups, each containing 11 pigs, received either a heavyweight polypropylene mesh (Atrium) or an identical but titanium-coated mesh (titanium-coated Atrium) implanted into the left groin using the totally endoscopic extraperitoneal patchplasty technique. RESULTS: A significant difference in the shrinkage behavior between conventional Atrium and titanium-coated Atrium was found (14.9 vs. 8.8%, p < 0.05). Furthermore, the partial volume of the inflammatory infiltrate also proved to be smaller with the titanium-coated mesh (14.9 vs. 12.4%). In addition, Ki-67 expression was lower in the group implanted with titanium-coated mesh (21.0 vs. 15.0%). No difference was observed with regard to the apoptosis index (7.6 vs. 6.5). CONCLUSIONS: Heavyweight titanium-coated polypropylene meshes induce a less pronounced foreign body reaction in comparison with identical meshes with no titanium coating, which, since the amount of material implanted is identical, must be attributed solely to the titanium coating.

Animals↗
PubMed2005

Long-term surgical results of pubovaginal sling procedure using polypropylene mesh in the treatment of stress urinary incontinence.

INTRODUCTION: Surgery for stress urinary incontinence (SUI) in women might cure incontinence symptom but develop new problems. This study assessed the long-term outcome of pubovaginal sling procedure using polypropylene mesh in patients with SUI. MATERIALS AND METHODS: A total of 108 patients with various types of SUI received pubovaginal sling procedure using polypropylene mesh. A surgical technique that did not create bladder outlet obstruction after operation was used in all the patients. Video urodynamic study was performed at baseline, 2 weeks and 3 months after operation. The long-term surgical results and patients' satisfaction were assessed. RESULTS: The age of patients ranged from 33 to 94 years (mean 62.6 +/- 12.0 years). The follow-up period ranged from 24 to 72 months (median 46 months). Among the 108 patients, a successful result was noted in 92 (85.2%), including a continence rate of 65.7% and mild SUI in 19.4% of patients. Treatment failure was noted in 16 patients (14.8%), including 13 (12%) with urge incontinence and 3 (2.8%) with severe SUI that was cured by a second sling. There were 104 patients (96.3%) who could void volitionally with little residual urine, whereas 4 (3.7%) needed transvaginal urethrolysis. Urodynamic study revealed no significant changes in the mean values of parameters at 3 months after operation. However, 22 (20%) patients had an increase in voiding pressure by 50% at 3 months postoperatively. The reported satisfactory rate was 89.8%. CONCLUSIONS: Pubovaginal sling procedure using polypropylene mesh had a high success rate in all types of SUI. The continence rate was suboptimal, indicating that the absence of bladder outlet obstruction might result in inadequate urethral compression after pubovaginal sling procedure.

Adult↗
PubMed2006

Hyaluronic acid/carboxymethylcellulose membrane barrier versus taurolidine for the prevention of adhesions to polypropylene mesh.

BACKGROUND: A hyaluronic acid/carboxymethylcellulose (HA/CMC) membrane is an effective measure to prevent polypropylene mesh induced adhesions. We hypothesized that taurolidine 2% solution might be a cost-effective alternative to decrease adhesion formation. MATERIALS AND METHODS: Twenty-four rats were randomized into three groups: mesh alone (group 1), mesh + taurolidine 2% (group 2), and mesh + HA/CMC (group 3). Polypropylene mesh (4 cm2) was used to repair surgically induced anterior abdominal wall defects. Taurolidine 2%or a HA/CMC membrane was used as an antiadhesive measure. The animals were sacrificed 6 weeks after the operation, and adhesions to the prosthetic material were evaluated with digital image analysis. RESULTS: Group 1 (mesh alone) had the highest adhesion ratio (58.5 +/- 4.8%) compared with groups 2 and 3 (p < 0.05). The differences between groups 2 (mesh + taurolidine 2%; adhesion ratio 42.9 +/- 1.6%) and 3 (mesh + HA/CMC; adhesion ratio 40.3 +/- 3.0%) were not significant (p > 0.05). CONCLUSIONS: The animals of both treatment groups (2 and 3) had lower adhesion ratios compared with the controls (group 1). In particular, the HA/CMC membrane did not present with a superior antiadhesive effect compared with taurolidine. Therefore, taurolidine is a cost-effective alternative to HA/CMC membranes when a polypropylene mesh is used in direct contact with the abdominal viscera.

Animals↗
PubMed1994

Stability of ondansetron stored in polypropylene syringes.

OBJECTIVE: To evaluate the stability of ondansetron hydrochloride undiluted and mixed in dextrose 5% injection or NaCl 0.9% injection during storage in polypropylene syringes when frozen, refrigerated, or at room temperature. DESIGN: Batch quantities of ondansetron 0.25, 0.5, 1.0, and 2.0 mg/mL were prepared and individual doses of 10.5 mg were drawn into polypropylene syringes that were stored at -20 degrees C for up to 3 months, at 4 degrees C for up to two weeks, or at 22-25 degrees C for two days, and various combinations of these conditions. At defined sampling times aliquots were withdrawn from syringes, the solution visually inspected, pH measured, and ondansetron concentration determined by HPLC. Drug loss of > or = 10 percent of the original content of the solution was considered clinically significant. RESULTS: The ondansetron concentration in each solution, regardless of storage conditions, remained above 90 percent of the original concentration at each observation time (range 92-107 percent). No changes in color or clarity of any of the solutions were observed, and only slight fluctuations in pH (< or = 0.05) were noted. CONCLUSIONS: Ondansetron 2 mg/mL undiluted, or at concentrations of 0.25, 0.5, or 1 mg/mL, mixed in dextrose 5% injection or NaCl 0.9% injection was determined to be stable when stored in polypropylene syringes for each storage condition at all time points studied, including the maximum for each: three months at -20 degrees C, followed by 14 days at 4 degrees C, and by 48 hours at 22-25 degrees C.

Drug Stability↗
PubMed2002

Structural integrity of polypropylene prosthetic sockets manufactured using the polymer deposition technique.

Rapid prototyping (RP) technology has been used recently as a means for automated socket fabrication. Although the technology has proven to be promising and has truly automated the socket fabrication process, the structural integrity of RP sockets remains questionable. For the long term, unsupervised use of these 'unconventional' sockets, their material properties and structural integrity must be determined. This study investigated the structural integrity of polypropylene sockets manufactured using a polymer deposition technique, in which a socket is formed by a continuous strand of partially melted polypropylene that is spirally deposited according to the socket's cross-sectional contour. To investigate the problem of delamination of the socket, the tensile properties of the socket material were determined according to ASTM D638-99. The ultimate tensile strength was found to be approximately 13-23 per cent lower than that of polypropylene sheets that are at present normally used for socket fabrication. In order to improve the load-bearing capacity of the socket, it was reinforced using a double-wall arrangement at the distal region, where failure normally occurs. The structural integrity of the complete prosthesis was then investigated according to ISO 10328 (loading condition II). The prosthesis passed the static loading test registering only 12 mm permanent deformation, and it successfully completed a preliminary cyclic test of 250,000 cycles with no observable failure.

Computer-Aided Design↗
PubMed2004

Foreign body attachment to polypropylene suture material extruded into the small intestinal lumen after enteric closure in three dogs.

Three dogs in which polypropylene suture material was used to close an enteric surgery site in a continuous pattern were evaluated at a later date because of recurrence of signs of intestinal disease. Surgery in each dog revealed that the suture material had been extruded into the lumen of the intestine and acted as a site for attachment of a foreign body. The nonabsorbable nature of polypropylene and its use in a continuous pattern are possible explanations for this complication. Polydioxanone or poliglecaprone 25 may be suitable alternatives to polypropylene for use in a continuous pattern for closure of small intestinal surgery sites.

Animals↗
PubMed1999

Comparison of bending stiffness of six different colours of copolymer polypropylene.

This paper compares the bending stiffness of 5 different colours of copolymer polypropylene (CCP) with that of natural copolymer polypropylene (NCP). Flesh coloured and natural sheets are supplied thicker than other pigmented sheet. The bending stiffness of a specimen may be defined as EI, i.e. the product of E, Young's modulus of elasticity and I, the 2nd moment of area. Strips of "as supplied" (AS) and "post-draped" (PD) specimen were clamped and subjected to bending to assess the effect of pigmentation on bending characteristics. The gradient of the graph of bending deflection delta versus bending moment enables EI to be estimated. The process of thermoforming polypropylene reduces EI, the bending stiffness. However, the manual draping and vacuum procedure introduces so many variables that it is difficult to quantify the effect of pigmentation. The E of a bent specimen may be estimated from the gradient of the graph of deltaI versus bending moment. In the case of AS sheet, the effect of pigmentation on E is inconclusive. PD specimens indicate a significant reduction in E due to thermoforming. This was verified by an electron-microscope study of AS and PD specimens. Draping an ankle-foot orthosis (AFO) results in a non-uniform wall thickness. The results of this study with respect to the effects of pigmentation on the bending stiffness of AFOs are inconclusive. More detailed studies require to be completed in order to confirm which factors are responsible for this non-uniformity in wall thickness and consequent variation in bending stiffness.

Biomechanical Phenomena↗
PubMed1993

Polypropylene serving the medical sector.

Polypropylene has a range of properties that make it suitable for use in the manufacture of health care products. These properties can be varied to suit different applications and this has led to its increasing market share in the health care sector. This article discusses recent developments in polypropylene technology and some new applications, highlighting the benefits of polypropylene over the more traditional materials.

Equipment and Supplies↗
PubMedDate not supplied

Repair of complex giant ventral hernias with polypropylene and omentoplasty.

The Authors in this report describe their experience with complex giant ventral hernias repaired by omentoplasty and polypropylene meshes. They explain their own technique of using the omentum when there is a lack of tissue and the need of an autologous tissue to place between the viscera and the above-lying polypropylene mesh. Among the 5 patients repaired, 4 had a giant sub-umbilical midline ventral hernia and one had a giant border ventral hernia. In all patients, the omentum was placed between the viscera and the mesh, which was fixed by interrupted sutures to the above-lying musculoaponeurotic plane. No complications, signs of bowel obstruction, or recurrences occurred. The Authors stress the omentum as an ideal tissue because of its biocompatibility and prevention of adhesions and fistulas allowing the use of a rigid and efficient prosthesis such as polypropylene. Thus, on the basis of their own short- and long-term good results, they suggest, whenever possible and necessary, the use of omentoplasty to repair complex giant ventral hernias.

Aged↗
PubMed2001

Polypropylene sling for treatment of stress urinary incontinence: an alternative to tension-free vaginal tape.

PURPOSE: Sling procedures have been used successfully to treat stress urinary incontinence (SUI). We report our initial experience with the use of a synthetic polypropylene mesh for treatment of SUI. Based on similar surgical principles of cadaveric fascia sling, we describe placement of a thinly woven polypropylene mesh under the distal urethra. We describe our technique and report our initial results. MATERIALS AND METHODS: There were 146 consecutive patients evaluated. All patients had clinical evidence of SUI. Patients underwent preoperative evaluation with video urodynamics, symptom questionnaire, and cystoscopy. Postoperatively the patients were evaluated at 3-month intervals by symptom questionnaire, physical examination, and postvoid residuals (PVR). One year after the procedure, all patients were asked to fill out a voiding dysfunction and incontinence symptom questionnaire and a validated quality-of-life questionnaire. A flow and PVR also were obtained. RESULTS: Average intraoperative time was 27 minutes for the sling procedure. There were no intraoperative complications and one major postoperative complication. There was no permanent retention and no erosions. Ninety-two percent of patients had either no or rare stress incontinence. Postoperatively, 7% of patients developed de novo urge incontinence. CONCLUSION: We describe excellent results with a new simple, quick, and inexpensive method to correct SUI by placing a polypropylene mesh under the distal urethra.

Cystoscopy↗
PubMed2002

[Analysis on energy consuming of polypropylene tubular membrane microfiltration in rotating tangential flow].

A new type of polypropylene tubular membrane module in rotating tangential flow was designed to experimentally study energy consuming of the polypropylene PA tubular membrane microfiltration. Through the experimental system of rotating tangential flow which was set up to enhance the microfiltration, the polypropylene PA tubular membrane fluxes and energy efficiency of rotating tangential flow and axial flow were measured under different fluid pressures. The experimental results demonstrate that rotary tangential flow tubular membrane microfiltration was a high efficiency technology of membrane separation. At test conditions, the stable energy efficiency of linear and circular tangential flow were higher than 11.185 times and 14.591 times of the stable energy applying efficiency of axial flow respectively.

Energy Transfer↗