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Journal of Orthopaedic Research :... Apr 2021Masquelet's induced membrane technique (MIMT) is a relatively new, two-stage surgical procedure to reconstruct segmental bone defects. First performed by Dr. Masquelet... (Review)
Review
Masquelet's induced membrane technique (MIMT) is a relatively new, two-stage surgical procedure to reconstruct segmental bone defects. First performed by Dr. Masquelet in the mid-1980s, MIMT has shown great promise to revolutionize critical-sized bone defect repair and has several advantages over its alternative, distraction osteogenesis (DO). Also, its success in extremely challenging cases (defects > 15 cm) suggests that its study could lead to discovery of novel biological mechanisms that might be at play during segmental defect healing and fracture non-union. MIMT's advantages over DO have led to a world-wide increase in MIMT procedures over the past decades. However, MIMT often needs to be repeated and so the average initial success rate in adults lags significantly behind that of DO (86% vs 95%, respectively). The autologous foreign-body membrane created during the first stage by the immune system's response to a polymethyl methacrylate bone cement spacer is critical to supporting the morselized bone graft implanted in the second stage. However, the biological and/or physical mechanisms by which the membrane supports graft to bone union are unclear. This lack of knowledge makes refining MIMT and improving the success rates through technique improvements and patient selection a significant challenge and hinders wider adoption. In this review, current knowledge from basic, translational, and clinical studies is summarized. The dynamics of both stages under normal conditions as well as with drug or material perturbations is discussed along with perspectives on high-priority future research directions.
Topics: Bone Cements; Bone Transplantation; Bone and Bones; Foreign-Body Reaction; Fracture Healing; Fractures, Bone; Humans; Immune System; Orthopedics; Osteogenesis; Polymethyl Methacrylate; Regeneration; Treatment Outcome
PubMed: 33382115
DOI: 10.1002/jor.24978 -
Medicina Oral, Patologia Oral Y Cirugia... May 2023Adverse reactions, caused during the inflammation and healing process, or even later, can be induced by the injection of dermal filler and can present a variety of...
BACKGROUND
Adverse reactions, caused during the inflammation and healing process, or even later, can be induced by the injection of dermal filler and can present a variety of clinical and histological characteristics. In this study we aimed to review the adverse reactions associated with the injection of aesthetic filling materials in the face and neck.
MATERIAL AND METHODS
The review was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. Studies published that mentioned adverse reactions in patients with aesthetic filling materials in the face or neck were included. Risk of bias was assessed using the Joanna Briggs Institute appraisal tool. After a 2-step selection process, 74 studies were included: 51 case reports, 18 serial cases, and five cohorts.
RESULTS
A total of 303 patients from 20 countries were assessed. Lesions were more prevalent in the lip (18%), nasolabial folds (13%), cheeks (13%), chin (10%), submental (8%), glabella (7%), and forehead (6%). Histopathological analysis revealed a foreign body granuloma in 87.1% of the patients, 3% inflammatory granuloma, 3% lipogranuloma, 2.3% xanthelasma-like reaction, 1% fibrotic reaction, 0.7% amorphous tissues, 0.7% xanthelasma, 0.3% sclerosing lipogranuloma, 0.3% siliconoma, and 0.3% foreign body granuloma with scleromyxedema. In addition, two patients displayed keratoacanthoma and two others displayed sarcoidosis after cutaneous filling. The most commonly used materials were silicone fillers (19.7%), hyaluronic acid (15.5%), and hydroxyethyl methacrylate/ethyl methacrylate suspended in hyaluronic acid acrylic hydrogel (5.6%). All patients were treated, and only 12 had prolonged complications.
CONCLUSIONS
There is evidence that adverse reaction can be caused by different fillers in specific sites on the face. Although foreign body granuloma was the most common, other adverse lesions were diagnosed, exacerbating systemic diseases. In this way, we reinforce the importance of previous systemic evaluations and histopathological analyses for the correct diagnosis of lesions.
Topics: Humans; Granuloma, Foreign-Body; Cosmetic Techniques; Hyaluronic Acid; Esthetics, Dental; Polymethyl Methacrylate
PubMed: 36565218
DOI: 10.4317/medoral.25713 -
International Journal of Molecular... Sep 2022Polymethyl methacrylate (PMMA), a well-known polymer of the methacrylate family, is extensively used in biomedicine, particularly in odontological applications including... (Review)
Review
Polymethyl methacrylate (PMMA), a well-known polymer of the methacrylate family, is extensively used in biomedicine, particularly in odontological applications including artificial teeth, dentures and denture bases, obturators, provisional or permanent crowns, and so forth. The exceptional PMMA properties, including aesthetics, inexpensiveness, simple manipulation, low density, and adjustable mechanical properties, make it a perfect candidate in the field of dentistry. However, it presents some deficiencies, including weakness regarding hydrolytic degradation, poor fracture toughness, and a lack of antibacterial activity. To further enhance its properties and solve these drawbacks, different approaches can be performed, including the incorporation of nanofillers. In this regard, different types of metallic nanoparticles, metal oxide nanofillers, and carbon-based nanomaterials have been recently integrated into PMMA matrices with the aim to reduce water absorption and improve their performance, namely their thermal and flexural properties. In this review, recent studies regarding the development of PMMA-based nanocomposites for odontology applications are summarized and future perspectives are highlighted.
Topics: Anti-Bacterial Agents; Carbon; Denture Bases; Materials Testing; Methacrylates; Nanocomposites; Oxides; Polymers; Polymethyl Methacrylate; Surface Properties; Water
PubMed: 36142201
DOI: 10.3390/ijms231810288 -
Nature Communications Aug 2022The global-scale production of plastics has been instrumental in advancing modern society, while the rising accumulation of plastics in landfills, oceans, and anything...
The global-scale production of plastics has been instrumental in advancing modern society, while the rising accumulation of plastics in landfills, oceans, and anything in between has become a major stressor on environmental sustainability, climate, and, potentially, human health. While mechanical and chemical forces of man and nature can eventually break down or recycle plastics, our understanding of the biological fingerprints of plastics, especially of nanoplastics, remains poor. Here we report on a phenomenon associated with the nanoplastic forms of anionic polystyrene and poly(methyl methacrylate), where their introduction disrupted the vascular endothelial cadherin junctions in a dose-dependent manner, as revealed by confocal fluorescence microscopy, signaling pathways, molecular dynamics simulations, as well as ex vivo and in vivo assays with animal model systems. Collectively, our results implicated nanoplastics-induced vasculature permeability as primarily biophysical-biochemical in nature, uncorrelated with cytotoxic events such as reactive oxygen species production, autophagy, and apoptosis. This uncovered route of paracellular transport has opened up vast avenues for investigating the behaviour and biological effects of nanoplastics, which may offer crucial insights for guiding innovations towards a sustainable plastics industry and environmental remediation.
Topics: Animals; Humans; Male; Microplastics; Plastics; Polymethyl Methacrylate; Polystyrenes; Reactive Oxygen Species
PubMed: 35963861
DOI: 10.1038/s41467-022-32532-5 -
BMC Musculoskeletal Disorders Oct 2022Antibiotic-loaded bone cement beads and spacers have been widely used for orthopaedic infection. Poor antibiotic elution is not capable of eradicating microbial...
OBJECTIVE
Antibiotic-loaded bone cement beads and spacers have been widely used for orthopaedic infection. Poor antibiotic elution is not capable of eradicating microbial pathogens and could lead to treatment failure. The elution profiles differ among different cement formulations. Although Simplex P cement has the least release amount, it is widely used due to its ready availability. Previous methods aiming to improve the elution profiles were not translated well to clinical practice. We sought to address this by using easily available materials to improve the elution profile of antibiotics from PMMA, which allows clinicians to implement the method intraoperatively.
METHODS
Vancomycin was mixed with Simplex P cement. We used Vicryl Rapide sutures to fabricate sustained-release cement beads by repetitively passing the sutures through the beads and/or mixing suture segments into the cement formulation. Vancomycin elution was measured for 49 days. The mechanism of antibiotic release was observed with gross appearance and scanning electron microscopic images. The antimicrobial activities against MRSA were tested using an agar disk diffusion bioassay.
RESULTS
Passing Vicryl Rapide sutures through cement beads significantly improved the elution profiles in the 7-week period. The increased ratios were 9.0% on the first day and 118.0% from the 2nd day to the 49th day. Addition of suture segments did not increase release amount. The Vicryl Rapide sutures completely degraded at the periphery and partially degraded at the center. The antibiotic particles were released around the suture, while antibiotic particles kept densely entrapped in the control group. The antimicrobial activities were stronger in passing suture groups.
CONCLUSION
Passing fast absorbable sutures through PMMA cement is a feasible method to fabricate sustained-release antibiotic bone cement. Intra-cement tunnels can be formed, and the effect can last for at least 7 weeks. It is suitable for a temporary spacer between two stages of a revision surgery.
Topics: Agar; Anti-Bacterial Agents; Bone Cements; Delayed-Action Preparations; Humans; Methylmethacrylate; Polyglactin 910; Polymethyl Methacrylate; Sutures; Vancomycin
PubMed: 36242041
DOI: 10.1186/s12891-022-05870-0 -
Analytica Chimica Acta May 2022As a result of their favorable physical and chemical characteristics, thermoplastics have garnered significant interest in the area of microfluidics. The moldable nature... (Review)
Review
As a result of their favorable physical and chemical characteristics, thermoplastics have garnered significant interest in the area of microfluidics. The moldable nature of these inexpensive polymers enables easy fabrication, while their durability and chemical stability allow for resistance to high shear stress conditions and functionalization, respectively. This review provides a comprehensive examination several commonly used thermoplastic polymers in the microfluidics space including poly(methyl methacrylate) (PMMA), cyclic olefin polymer (COP) and copolymer (COC), polycarbonates (PC), poly(ethylene terephthalate) (PET), polystyrene (PS), poly(ethylene glycol) (PEG), polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), and polyester. We describe various biofunctionalization strategies applied within thermoplastic microfluidic platforms and their resultant applications. Lastly, emerging technologies with a focus on applying recently developed microfluidic and biofunctionalization strategies into thermoplastic systems are discussed.
Topics: Microfluidics; Plastics; Polyethylene Terephthalates; Polymers; Polymethyl Methacrylate; Polystyrenes
PubMed: 35569863
DOI: 10.1016/j.aca.2021.339283 -
Biosensors Aug 2021This review summarizes and compares the available surface treatment and bonding techniques (e.g., corona triggered surface activation, oxygen plasma surface activation,... (Review)
Review
This review summarizes and compares the available surface treatment and bonding techniques (e.g., corona triggered surface activation, oxygen plasma surface activation, chemical gluing, and mixed techniques) and quality/bond-strength testing methods (e.g., pulling test, shear test, peel test, leakage test) for bonding PDMS (polydimethylsiloxane) with other materials, such as PDMS, glass, silicon, PET (polyethylene terephthalate), PI (polyimide), PMMA (poly(methyl methacrylate)), PVC (polyvinyl chloride), PC (polycarbonate), COC (cyclic olefin copolymer), PS (polystyrene) and PEN (polyethylene naphthalate). The optimized process parameters for the best achievable bond strengths are collected for each substrate, and the advantages and disadvantages of each method are discussed in detail.
Topics: Cycloparaffins; Dimethylpolysiloxanes; Microfluidic Analytical Techniques; Microfluidics; Polycarboxylate Cement; Polymers; Polymethyl Methacrylate; Silicon; Surface Properties; Temperature
PubMed: 34436094
DOI: 10.3390/bios11080292 -
Science (New York, N.Y.) Jul 2019Artificial muscles may accelerate the development of robotics, haptics, and prosthetics. Although advances in polymer-based actuators have delivered unprecedented...
Artificial muscles may accelerate the development of robotics, haptics, and prosthetics. Although advances in polymer-based actuators have delivered unprecedented strengths, producing these devices at scale with tunable dimensions remains a challenge. We applied a high-throughput iterative fiber-drawing technique to create strain-programmable artificial muscles with dimensions spanning three orders of magnitude. These fiber-based actuators are thermally and optically controllable, can lift more than 650 times their own weight, and withstand strains of >1000%. Integration of conductive nanowire meshes within these fiber-based muscles offers piezoresistive strain feedback and demonstrates long-term resilience across >10 deformation cycles. The scalable dimensions of these fiber-based actuators and their strength and responsiveness may extend their impact from engineering fields to biomedical applications.
Topics: Artificial Organs; Biomedical Engineering; Carbon Fiber; Muscle Fibers, Skeletal; Polymethyl Methacrylate; Prostheses and Implants; Robotics
PubMed: 31296764
DOI: 10.1126/science.aaw2502 -
Nature Communications Mar 2021All-electronic interrogation of biofluid flow velocity by electrical nanosensors incorporated in ultra-low-power or self-sustained systems offers the promise of enabling...
All-electronic interrogation of biofluid flow velocity by electrical nanosensors incorporated in ultra-low-power or self-sustained systems offers the promise of enabling multifarious emerging research and applications. However, existing nano-based electrical flow sensing technologies remain lacking in precision and stability and are typically only applicable to simple aqueous solutions or liquid/gas dual-phase mixtures, making them unsuitable for monitoring low-flow (~micrometer/second) yet important characteristics of continuous biofluids (such as hemorheological behaviors in microcirculation). Here, we show that monolayer-graphene single microelectrodes harvesting charge from continuous aqueous flow provide an effective flow sensing strategy that delivers key performance metrics orders of magnitude higher than other electrical approaches. In particular, over six-months stability and sub-micrometer/second resolution in real-time quantification of whole-blood flows with multiscale amplitude-temporal characteristics are obtained in a microfluidic chip.
Topics: Animals; Blood Flow Velocity; Cattle; Copper; Graphite; Lab-On-A-Chip Devices; Microelectrodes; Microfluidic Analytical Techniques; Physical Phenomena; Polymethyl Methacrylate
PubMed: 33741935
DOI: 10.1038/s41467-021-21974-y -
Orthopadie (Heidelberg, Germany) Dec 2023Processing properties of PMMA bone cements can be divided into four phases: 1. mixing, 2. waiting, 3. processing and 4. curing. Each of these phases is subject to... (Review)
Review
Processing properties of PMMA bone cements can be divided into four phases: 1. mixing, 2. waiting, 3. processing and 4. curing. Each of these phases is subject to several external influencing factors, such as temperature and humidity, which must be considered during application. Instructions for use provided by the manufacturers of PMMA bone cements and mixing and application systems contain important information on correct application. The processing properties of PMMA bone cements and possible factors influencing the curing process are of great importance for safe procedures in the operating room. Knowledge of the viscosity and consistency of the PMMA bone cement from the dough phase to complete curing facilitates preparation and application, which in the long term significantly improves the requirements placed on PMMA cements regarding the function and service life of the implant.
Topics: Bone Cements; Polymethyl Methacrylate; Viscosity; Temperature
PubMed: 37902859
DOI: 10.1007/s00132-023-04450-x