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Nature Reviews. Urology Nov 2019Vaginal meshes used in the treatment of stress urinary incontinence (SUI) and pelvic organ prolapse (POP) have produced highly variable outcomes, causing life-changing... (Review)
Review
Vaginal meshes used in the treatment of stress urinary incontinence (SUI) and pelvic organ prolapse (POP) have produced highly variable outcomes, causing life-changing complications in some patients while providing others with effective, minimally invasive treatments. The risk:benefit ratio when using vaginal meshes is a complex issue in which a combination of several factors, including the inherent incompatibility of the mesh material with some applications in pelvic reconstructive surgeries and the lack of appropriate regulatory approval processes at the time of the premarket clearance of these products, have contributed to the occurrence of complications caused by vaginal mesh. Surgical mesh used in hernia repair has evolved over many years, from metal implants to knitted polymer meshes that were adopted for use in the pelvic floor for treatment of POP and SUI. The evolution of the material and textile properties of the surgical mesh was guided by clinical feedback from hernia repair procedures, which were also being modified to obtain the best outcomes with use of the mesh. Current evidence shows how surgical mesh fails biomechanically when used in the pelvic floor and materials with improved performance can be developed using modern material processing and tissue engineering techniques.
Topics: Equipment Design; Female; Humans; Pelvic Organ Prolapse; Polypropylenes; Surgical Mesh; Urinary Incontinence, Stress; Vagina
PubMed: 31548731
DOI: 10.1038/s41585-019-0230-2 -
The Science of the Total Environment Nov 2022Among the indirect environmental impacts generated by the global COVID-19 pandemic, contamination with personal protective equipment (PPE), like face masks, may be one...
Among the indirect environmental impacts generated by the global COVID-19 pandemic, contamination with personal protective equipment (PPE), like face masks, may be one of the most relevant ones. PPE has been found in multiple aquatic, marine, and terrestrial environments, including places of absolute relevancy to biodiversity conservation, such as protected areas (PAs). Here, a brief report of the presence of PPE in six PAs of Peru is presented. PPE pollution in PAs consisted mainly of single-use and reusable face masks, as well as plastics associated with PAs, such as KN95 respirator wrappings. The mean PPE density was estimated as 1.32 × 10 PPE/m. FTIR spectroscopy confirmed that face masks and wrappers mainly consisted of polypropylene and polyethylene, two of the most commonly available synthetic polymers. The material was poorly degraded according to their FTIR spectra, possibly suggesting that they were discarded recently. The recent ban on single-use plastic in Peruvian PAs is regarded as a great step forward toward the efforts made to preserve these invaluable places. However, these measures seemed insufficient to prevent PPE and other types of litter from contaminating areas of ecological importance. Considering the current scenario, several recommendations were proposed to be implemented in PAs in order to prevent PPE from becoming a new plastic issue to tackle. These recommendations are expected to also serve for future events where the use of single-use plastics becomes inevitable, like global pandemics.
Topics: COVID-19; Humans; Masks; Pandemics; Plastics; Polyethylenes; Polypropylenes
PubMed: 35905957
DOI: 10.1016/j.scitotenv.2022.157636 -
Cytotoxicity of polymers intended for the extrusion-based additive manufacturing of surgical guides.Scientific Reports May 2022Extrusion-based printing enables simplified and economic manufacturing of surgical guides for oral implant placement. Therefore, the cytotoxicity of a biocopolyester...
Extrusion-based printing enables simplified and economic manufacturing of surgical guides for oral implant placement. Therefore, the cytotoxicity of a biocopolyester (BE) and a polypropylene (PP), intended for the fused filament fabrication of surgical guides was evaluated. For comparison, a medically certified resin based on methacrylic esters (ME) was printed by stereolithography (n = 18 each group). Human gingival keratinocytes (HGK) were exposed to eluates of the tested materials and an impedance measurement and a tetrazolium assay (MTT) were performed. Modulations in gene expression were analyzed by quantitative PCR. One-way ANOVA with post-hoc Tukey tests were applied. None of the materials exceeded the threshold for cytotoxicity (< 70% viability in MTT) according to ISO 10993-5:2009. The impedance-based cell indices for PP and BE, reflecting cell proliferation, showed little deviations from the control, while ME caused a reduction of up to 45% after 72 h. PCR analysis after 72 h revealed only marginal modulations caused by BE while PP induced a down-regulation of genes encoding for inflammation and apoptosis (p < 0.05). In contrast, the 72 h ME eluate caused an up-regulation of these genes (p < 0.01). All evaluated materials can be considered biocompatible in vitro for short-term application. However, long-term contact to ME might induce (pro-)apoptotic/(pro-)inflammatory responses in HGK.
Topics: Gingiva; Humans; Keratinocytes; Polymers; Polypropylenes; Stereolithography
PubMed: 35513701
DOI: 10.1038/s41598-022-11426-y -
Toxics Mar 2023In recent years, polypropylene microplastic has persisted in freshwater ecosystems and biota, forming ever-growing threats. This research aimed to prepare polypropylene...
In recent years, polypropylene microplastic has persisted in freshwater ecosystems and biota, forming ever-growing threats. This research aimed to prepare polypropylene microplastics and evaluate their toxicity to the filter feeder . In this research, fish were given a dietary supplement of polypropylene microplastics at 100, 500, and 1000 mg/kg for acute (96 h) and sub-acute (14 days) durations to assess toxic effects on liver tissues. FTIR results revealed the presence of polypropylene microplastic in their digestion matter. The ingestion of microplastics in led to fluctuations in homeostasis, an upsurge in reactive oxygen species (ROS) levels, an alteration in antioxidant parameters, including superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), and glutathione peroxidase (GPx); a promotion in the oxidation of lipid molecules; and a denaturation in the neurotransmitter enzyme acetylcholinesterase (AChE). Our data indicated that sustained exposure to microplastics (14 days) produced a more severe threat than acute exposure (96 h). In addition, higher apoptosis, DNA damage (genotoxicity), and histological changes were found in the liver tissues of the sub-acute (14 days) microplastics-treated groups. This research indicated that the constant ingestion of polypropylene microplastics is detrimental to freshwater environments and leads to ecological threats.
PubMed: 36977047
DOI: 10.3390/toxics11030282 -
Journal of Biomedical Materials... Oct 2022Polyvinylidene fluoride (PVDF) has been considered as an alternative suture material to replace polypropylene (PP) due to its superior biocompatibility and mechanical...
Polyvinylidene fluoride (PVDF) has been considered as an alternative suture material to replace polypropylene (PP) due to its superior biocompatibility and mechanical properties, but it has never been examined for use in barbed sutures, particularly for tendon repair. This study fabricated size 2-0 PVDF and PP bidirectional barbed sutures and compared their mechanical properties and anchoring performance in patellar tendons. The mechanical properties were evaluated via tensile testing, and the anchoring performance of the barbed sutures was assessed by a tendon suture pullout test. Sixty porcine patellar tendons were harvested, transected to mimic a full-thickness injury, and repaired using a cross-locked cruciate suturing technique. The ultimate tensile force was 60% higher for the PVDF barbed sutures (22.4 ± 2.1 N) than for the PP barbed sutures (14.0 ± 1.7 N). The maximum pullout force was 35% higher for PVDF barbed sutures (70.8 ± 7.8 N) than for PP barbed sutures (52.4 ± 5.8 N). The force needed to form a 2-mm gap, indicative of repair failure, was similar between the PVDF (29.2 ± 5.0 N) and PP (25.6 ± 3.1 N) barbed sutures, but both were greater than the 2-mm-gap forces for non-barbed sutures of the same size. In this study, PVDF barbed sutures provided better mechanical properties and improved tissue anchoring performance compared to the barbed PP sutures for porcine patellar tendon repair, demonstrating that PVDF monofilament sutures can be barbed and used effectively for tendon repair.
Topics: Animals; Biomechanical Phenomena; Fluorocarbon Polymers; Polypropylenes; Polyvinyls; Suture Techniques; Sutures; Swine; Tendon Injuries; Tendons; Tensile Strength
PubMed: 35674273
DOI: 10.1002/jbm.b.35074 -
Polymers Feb 2023Polypropylene (PP)/sepiolite nanocomposites were prepared using the melt blending technique. The effects of nano-sepiolite content on the mechanical property, thermal...
Polypropylene (PP)/sepiolite nanocomposites were prepared using the melt blending technique. The effects of nano-sepiolite content on the mechanical property, thermal property, crystallinity, morphology and rheological property of PP/sepiolite nanocomposites were investigated. The organic modified sepiolites (OSep) were dispersed evenly in PP matrix after surface treatment. The addition of OSep improved the storage modulus and thermal stability, showing a strong interaction between OSep and PP matrix. With the increase of OSep content, the fluidity of PP/OSep composites first increased due to the lubrication of surface modifiers and then decreased due to the interaction between OSep and PP. The size of the toughening agent elastomer first increased and then decreased, and the impact notched strength of PP/Osep composites first decreased and then increased. The loading of OSep also reduced the crystallinity and shrinkage rate of PP. PP/OSep nanocomposites have potential applications in high-performance automotive lightweight materials.
PubMed: 36850086
DOI: 10.3390/polym15040802 -
Materials (Basel, Switzerland) Jan 2023The rubber particles obtained from the grinding of waste tires can replace a portion of the fine aggregates in concrete, thus effectively reducing the level of...
The rubber particles obtained from the grinding of waste tires can replace a portion of the fine aggregates in concrete, thus effectively reducing the level of environmental damage and saving resources. However, when concrete is mixed with rubber, it greatly reduces its strength. In this study, by introducing basalt fiber (BF) and polypropylene fiber (PF) as modified materials in rubberized concrete, the influence of the fiber type/volume ratio on the slump, water absorption, static uniaxial compression, and permeability of the rubberized concrete was tested. The axial compression stress-strain relationship was analyzed, the effect of the fiber type/volume ratio on the energy dissipation of the rubberized concrete during uniaxial compression was expounded, and a stress-strain constitutive model under uniaxial compression was established. The test results showed that the fiber reduces the fluidity and water absorption of the rubberized concrete. Compared with the polypropylene fiber, the basalt fiber increased the strength of the rubberized concrete, while the polypropylene fiber mainly inhibited the expansion and penetration of the macroscopic crack of the rubberized concrete. The mixing of the basalt fiber and polypropylene fiber significantly decreased the release rate of the elastic strain energy of the rubberized concrete, increased the dissipation energy, and thus improved its ductility and toughness. During a loading process under confining pressure, the permeability of the tested specimen decayed exponentially, and the fiber greatly enhanced the anti-permeability of the rubber concrete.
PubMed: 36676214
DOI: 10.3390/ma16020481 -
Heliyon Jul 2023This study aims to compare the clinical outcomes of complications, quality of life, and chronic pain between titanium-coated polypropylene mesh and polypropylene mesh...
OBJECTIVE
This study aims to compare the clinical outcomes of complications, quality of life, and chronic pain between titanium-coated polypropylene mesh and polypropylene mesh after Lichtenstein or TAPP surgery.
METHODS
A retrospective cohort study was conducted, involving patients who underwent inguinal hernia repair using Timesh light®, Optilene LP®, or 3DMax™ meshes between January 2020 and May 2022. Based on the surgical method, patients were divided into Lichtenstein and TAPP groups, and further categorized according to the type of mesh used. The primary endpoints assessed postoperative complications, postoperative pain, and postoperative quality of life. Secondary endpoints included postoperative sensation in the surgical area and postoperative recurrence rate.
RESULTS
A total of 180 Lichtenstein procedures and 478 TAPP procedures were included in the analysis after propensity score matching. The findings revealed that patients with titanium-coated polypropylene mesh did not exhibit significant advantages in perioperative data. Within three months to one year after TAPP surgery, patients with the titanium-coated polypropylene mesh reported improved foreign body sensation during activities ( = 0.002) and a lower incidence of chronic pain ( = 0.008). However, after one year, these advantages of titanium-coated polypropylene mesh were no longer significant during activity or at rest. In the TAPP group, the titanium-coated polypropylene mesh depicted advantages in the single score of the SF-36 questionnaire.
CONCLUSIONS
The utilization of titanium-coated polypropylene mesh resulted in reduced foreign body sensation and chronic pain in activity within one year after TAPP surgery, significantly enhancing certain aspects of the patient's quality of life compared to polypropylene mesh.
PubMed: 37455954
DOI: 10.1016/j.heliyon.2023.e17691 -
International Journal of Molecular... Oct 2022During the production of polymer-grade propylene, different processes are used to purify this compound and ensure that it is of the highest quality. However, some...
During the production of polymer-grade propylene, different processes are used to purify this compound and ensure that it is of the highest quality. However, some impurities such as acetylene and methyl acetylene are difficult to remove, and some of these impurities may be present in the propylene used to obtain polypropylene, which may have repercussions on the process. This study evaluates the impact of these acetylene and methyl acetylene impurities on the productivity of the polypropylene synthesis process and on the mechanical and thermal properties of the material obtained through the synthesis of eight samples with different concentrations of acetylene and eight samples with different concentrations of acetylene. We discovered that for the first concentrations of both acetylene (2 and 3 ppm) and methyl acetylene (0.03 and 0.1), the MFI, thermal recording, and mechanical properties of the resin were unaffected by the variation of the fluidity index, thermal degradation by TGA, and mechanical properties such as resistance to tension, bending, and impact. However, when the concentration exceeded 14 ppm for methyl acetylene and 12 ppm for acetylene, the resistance of this resin began to decrease linearly. Regarding production, this was affected by the first traces of acetylene and methyl acetylene progressively decreasing.
Topics: Acetylene; Polypropylenes; Alkynes; Polymers
PubMed: 36293003
DOI: 10.3390/ijms232012148 -
Surgical Endoscopy Jul 2022Proposed mechanisms that potentially contribute to polypropylene mesh degradation after in vivo exposure include oxidizing species and mechanical strains induced by...
BACKGROUND
Proposed mechanisms that potentially contribute to polypropylene mesh degradation after in vivo exposure include oxidizing species and mechanical strains induced by normal healing, tissue integration, muscle contraction, and the immediate and chronic inflammatory responses.
METHODS
This study explores these potential degradation mechanisms using 63 mesh implants retrieved from patients after a median implantation time of 24 months following hernia repair surgery (mesh explants) and analysis of multivariate associations between the material changes and clinical characteristics. Specifically, polypropylene mesh degradation was characterized in terms of material changes in surface oxidation, crystallinity and mechanical properties, and clinical characteristics included mesh placement location, medical history and mesh selection.
RESULTS
Compared to pristine control samples, subsets of mesh explants had evidence of surface oxidation, altered crystallinity, or changed mechanical properties. Using multivariate statistical approach to control for clinical characteristics, infection was a significant factor affecting changes in mesh stiffness and mesh class was a significant factor affecting polypropylene crystallinity changes.
CONCLUSIONS
Highly variable in vivo conditions expose mesh to mechanisms that alter clinical outcomes and potentially contribute to mesh degradation. These PP mesh explants after 0.5 to 13 years in vivo had measurable changes in surface chemistry, crystallinity and mechanical properties, with significant trends associated with factors of mesh placement, mesh class, and infection.
Topics: Hernia; Humans; Materials Testing; Polypropylenes; Prostheses and Implants; Surgical Mesh
PubMed: 35257210
DOI: 10.1007/s00464-021-08882-4