Epithelial ingrowth is a LASIK complication in which cells from the cornea surface layer (epithelial cells) begin to grow underneath the corneal flap. Epithelial ingrowth is a rarely occurring LASIK complication, appearing in less than one percent of LASIK procedures. However, the incidence of epithelial ingrowth appears to be higher after subsequent enhancement LASIK procedures. This complication is not present in PRK or other non-flap vision correction procedures.
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Peritendinous tissues become macroscopically thickened and new connective tissue adhesions occur. In paratenonitis, inflammatory cells are found in the cellular elements of the paratenon and in the vascular ingrowth.
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Biocompatibility is related to new tissue ingrowth, fibroblast migration, osseointegration of bone, reduction of inflammation, preventing scar tissue infiltration, and improving hydrophilicity. Tissue ingrowth and fibroblast migration have been shown to improve the mechanical strength of the artificial ligament, and osseointegration with the surrounding bone can reduce the likelihood of graft slippage. Many artificial ligaments are designed to minimize inflammation and scar tissue infiltration because they can hinder the mechanical strength and can cause graft rupture. Artificial ligament design strives to improve hydrophilicity because hydrophobicity can trigger the host's natural response to foreign bodies.
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Typically, Rb/Sr increases in the order plagioclase, hornblende, K-feldspar, biotite, muscovite. Therefore, given sufficient time for significant production (ingrowth) of radiogenic 87Sr, measured 87Sr/86Sr values will be different in the minerals, increasing in the same order.
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Both implants (COI and MCOI) are composed of interconnecting channels that allow ingrowth of host connective tissue. Complete implant vascularization reduces the risk of infection, extrusion, and other complications associated with nonintegrated implants. And both implants produce superior motility and postoperative cosmesis.
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This knitted structure can help prevent deformation and abrasion. The intra-articular portion is made of longitudinal fibers pretwisted at a 90 degree angle. This section is designed to resist fatigue and promote tissue ingrowth. Leeds Keio ligaments consist of a polyester mesh structure.
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However, in the case of Medpor, the implants' integration and ingrowth with the underlying tissue causes difficulty removing the implant if revisions are needed.Augmentation options All About Cheek Augmentation: A Patient Education and Support Network. Last accessed 6 July 2009.High-density porous polyethylene implantseMedicine.
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SEMS also expand and can lead to perforation of the bowel or compression of structures adjacent to the bowel. Long-term complications of SEMS may be related to the underlying tumour being treated: the tumour may grow into the stent wall (tumour ingrowth) or over the end of the stent (tumour overgrowth), leading to obstruction. These complications may be limited by the use of coated stents. Tumour ingrowth or overgrowth can be additionally palliated by the placement of a second stent through the lumen of the first, through electrocautery or argon plasma coagulation of the tumour tissue in the stent, or through the use of photodynamic therapy.
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Smooth surfaces may be preferable to rougher ones as they may decrease the likelihood of bacterial adsorption and infection. Smooth surfaces would also make it more difficult for the initiation of a corrosion cell. However, creating a rougher, porous surface, may prove beneficial for at least two reasons: decreased potential polarization at the electrode surface as a result of increased surface area and decreased current density, and a decrease in fibrous tissue encapsulation thickness due to opportunity for tissue ingrowth. It has been determined that if interconnected pores with sizes between 25 and 150 micrometers, ingrowth of tissue can occur and can decrease the exterior tissue encapsulation thickness by a factor of approximately 10 (compared to a smooth electrode such as polished platinum-iridium).
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It can also be used for powder processing (spheroidization, homogenization, modification of chemistry, etc.). In this case, the substrate for deposition is absent and the particles solidify during flight or in a controlled environment (e.g., water). This technique with variation may also be used to create porous structures, suitable for bone ingrowth, as a coating for medical implants.
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It seeks to mimic the mechanical properties of the native ACL. The porous nature of the ligament can promote tissue ingrowth which has been shown to improve mechanical properties. The PGA Dacron artificial graft consists of 75% braided biodegradable polyglycolic acid and 25% permanent Dacron thread. The Kennedy LAD artificial ligament is made of polypropylene ribbons.
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It is designed to promote tissue ingrowth and the progressive transfer of load onto the new ligament. Ligament Advanced Reinforcement System (LARS) artificial ligament. The two end sections are the intraosseous portions and center portion is the intra-articular region. The native ACL of a human has a tensile strength on the order of kilonewtons, and an elongation at failure of approximately 10%.
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The GBR principle was first examined by Dahlin et al. in 1988 on rats. The selective ingrowth of bone-forming cells into a bone defect region could be improved if the adjacent tissue is kept away with a membrane; this was confirmed in a study by Kosopoulos and Karring in 1994. GBR can be used for bone regeneration on exposed implant coils .
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The perimeter of the hole in the skull is rounded off by ingrowth of new bony tissue, indicating that the person survived the operation. Trepanation, the deliberate drilling of holes into a skull, was practiced as early as 7,000 BCE. While sometimes people survived, many would have died from the procedure due to infection. It was believed to work via "letting evil spirits escape".
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The newly formed tissue were histologically examined. Resolution of symptoms of inflammation related to enlargement of foramen and overinstrumentation were observed in as early as 17 days. Resolution of apical periodontitis and signs and symptoms of inflammation and radiographic evidence of continued root development and apical narrowing were demonstrated in all teeth. Histology wise, ingrowth of connective tissue into the canal space was observed.
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SEMS may be coated with chemicals designed to prevent tumour ingrowth; these are termed "covered" stents. Nitinol (a shape memory nickel-titanium alloy), polyurethane, and polyethylene are typically used as coatings for SEMS. Covered stents carry the advantage of preventing tumours from growing into the stent, although they run the risk of increased migration after deployment. A plastic self-expanding stent (Polyflex, Boston Scientific) has also been developed for similar applications.
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Although it has not yet been commercialized for clinical use clinical studies have been done on intra- and extra-oral treatments with full-thickness engineered oral mucosa. Full-thickness engineered oral mucosa is mainly used in maxillofacial reconstructive surgery and periodontal peri-implant reconstruction. Good clinical and histological results have been obtained. For example, there is vascular ingrowth and the transplanted keratinocytes integrate well into the native epithelium.
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Specific types of long-term central lines are the Hickman catheters, which require clamps to make sure that the valve is closed, and Groshong catheters, which have a valve that opens as fluid is withdrawn or infused and remains closed when not in use. Hickman lines also have a "cuff" under the skin, to prevent bacterial migration. The cuff also causes tissue ingrowth into the device for long term securement.
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SEMS and self-expanding plastic stents have also been used for non-malignant conditions that cause narrowing or leaks of the esophagus or colon. These include peptic strictures caused by esophageal reflux and perforations of the esophagus. SEMS may also be placed in tandem fashion to treat ingrowth or overgrowth tumours, and fractures or migration of other SEMS. For the latter, the second SEMS in usually deployed within the lumen of the first.
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Osseoincorporation refers to the healing potential of bone onto an implant surface and into an implant structure. Three-dimensional, porous implantable materials used in the orthopedic and dental implant industries offer the potential for ingrowth as well as ongrowthUnger, AS. "Evaluation of a porous tantalum uncemented actetabular cup in revision total hip arthoplasty. Clinical and radiological results of 60 hips". J Arthroplasty, 2005, p 1002-1009Cohen R. "A porous tantalum trabedcular metal: basic science".
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The small, flexible inserts are made from polyester fibers, nickel-titanium, stainless steel and solder. The insert contains inner polyethylene terephthalate fibers to induce inflammation, causing a benign fibrotic ingrowth, and is held in place by flexible stainless steel inner coil and a dynamic outer nickel titanium alloy coil. Unlike temporary methods of birth control, the Essure inserts do not contain or release hormones. The inserts do not prevent the transmission of sexually transmitted infections.
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The most common digit to become ingrown is the big toe, but ingrowth can occur on any nail. Ingrown nails can be avoided by cutting nails straight across; not along a curve, not too short and no shorter than the flesh around it. Footwear that is too small or too narrow, or with too shallow a "toe box", will exacerbate any underlying problem with a toenail. Sharp square corners may be uncomfortable and cause snagging on socks.
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A physician places the coils into the fallopian tubes by a catheter passed from the vagina through the cervix and uterus. This occurs successfully between 63% and 100% of the time. Once in place, the ingrowth continues over a period of three months, resulting in blockage in the Fallopian tubes; the tissue barrier formed is supposed to prevent sperm from reaching an egg. During that intervening three-month period, women are advised to use an alternate contraceptive method.
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In 1985, the problems associated with integrated implants were thought to be largely solved with the introduction of spherical implants made of porous calcium hydroxyapatite. This material allows for fibrovascular ingrowth within several months. Porous enucleation implants currently are fabricated from a variety of materials including natural and synthetic hydroxyapatite, aluminium oxide, and polyethylene. The surgeon can alter the contour of porous implants before insertion, and it is also possible to modify the contour in situ, although this is sometimes difficult.
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J. Wayne Streilein (Johnstown, Pennsylvania, June 19, 1935 – March 15, 2004) was a scientist whose main area of research was the ocular immune system.Professor J. Wayne Streilein, 1935–2004 by Santa Jeremy Ono. Immunology. 2004 June; 112(2): 339–340. . He is known particularly for studying the mechanisms that keep the cornea avascular despite the inflammatory and other stimuli that usually promote small blood vessel ingrowth; these peculiar corneal mechanisms provide the basis for what is known as the "corneal antiangiogenic privilege".
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Melanin is another important endogenous absorber; it absorbs over a broad range of wavelengths in the visible and near-IR range, with absorption decreasing at longer wavelengths. Optoacoustic imaging of melanin has been used to assess the depth of melanoma ingrowth inside epithelial tissueH.F. Zhang, K. Maslov, G. Stoica, L.V. Wang, "Functional photoacoustic microscopy for high-resolution and noninvasive in vivo imaging", Nat Biotech 24 (2006) 848-851. and to assess the metastatic status of sentinel lymph nodes in melanoma patients.
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Traditional and rigid socket based technology is now replaced with a surgery that inserts a titanium implant into the bone. Osseoperception occurs as the prosthetic is anchored directly to the bone which would transmit sensory signals, resulting in patients recovering a certain level of feeling. The implant's surface is also made of highly porous titanium, providing the user with balance and allowing for ingrowth of bone. A dual adaptor is designed with a smooth surface to minimise friction and coated with titanium niobium for antibacterial purposes.
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Leeds-Keio artificial ligaments have an ultimate tensile strength near 2000 N and a stiffness around 250 N/mm after tissue ingrowth. LARS artificial ligaments have varying mechanical properties depending on the amount of fibers used. A higher gauged ligament will have a greater tensile strength. During testing, a 60 gauge LARS ligament exhibited an ultimate tensile strength of 2500 N while a 120 gauge ligament exhibited a tensile strength of 5600 N. The ingrown tissue has been shown to improve viscoelastic properties and reduce friction.
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This consists of several phases. After attachment of the distracting device and the bone cuts, there is a latency phase of 3–7 days when a callus forms. In the activation phase distraction of the callus induces bony ingrowth which can last up to 15 days depending on the required distraction. Once the required bone length is reached, the distraction device is left to remain in situ as it acts as a rigid skeletal fixation device until the new bone has matured (known as the consolidation period).
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In hydroxyapatite implants a secondary procedure can insert an externalized, round-headed peg or screw into the implant. The prosthesis is modified to accommodate the peg, creating a ball-and-socket joint: after fibrovascular ingrowth is completed, a small hole can be drilled into the anterior surface of the implant. After conjunctivalization of this hole, it can be fitted with a peg with a rounded top that fits into a corresponding dimple at the posterior surface of the artificial eye. This peg thus directly transfers implant motility to the artificial eye.
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Natural bone exhibits the ability to adjust local fiber away from the low-stress regions toward high stress regions through the distribution of porosity, thus maximizing overall comfort. Using finite element analysis, researchers examined the effect of filling pores with bone on mechanical properties. They concluded that bone ingrowth significantly improved the mechanical properties, evidenced by decreased localized plasticity and stress concentrations. In effect, the titanium foam in the study allowed the bone to exhibit its natural ability to adjust local fiber away from the low-stress regions toward high stress regions.
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PP proves an effective mesh for adjusting prolapsed organs, but may cause severe discomfort for the patient due to its high modulus of elasticity. This stiffens the prosthesis and results in a more pronounced inflammatory response, which complicates integration into the body with tissue ingrowth. As previously mentioned, PET too easily degrades in vivo and tissue has a difficult time integrating with PTFE. For these reasons, researchers are beginning to look for different types of surgical mesh that may be suitable for the biological environment and provide better comfort while supporting prolapsed organs.
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This can place the donor area at risk of recession as well. An acellular dermal matrix (such as Alloderm) graft uses donated medically processed human skin tissue as a source for the graft. The advantage of this procedure is no need for a palatal donor site, and though some periodontists consider it equally successful as a subepithelial connective tissue graft, others consider it less successful. Guided bone reconstruction is a technique in which bone growth is enhanced by preventing soft tissue ingrowth into the desired area and utilizes either resorbable or nonresorbable membranes.
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It serves a variety of functions, including space filling, lubrication of joints, and provision of a matrix through which cells can migrate. Hyaluronic acid is produced during wound healing and tissue repair to provide a framework for ingrowth of blood vessels and fibroblasts. Changes in the serum concentration of hyaluronic acid are associated with inflammatory and degenerative arthropathies such as rheumatoid arthritis. In addition, the interaction of hyaluronic acid with the leukocyte receptor CD44 is important in tissue-specific homing by leukocytes, and overexpression of hyaluronic acid receptors has been correlated with tumor metastasis.
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It serves a variety of functions, including space filling, lubrication of joints, and provision of a matrix through which cells can migrate. HA is actively produced during wound healing and tissue repair to provide a framework for ingrowth of blood vessels and fibroblasts. Changes in the serum concentration of HA are associated with inflammatory and degenerative arthropathies such as rheumatoid arthritis. In addition, the interaction of HA with the leukocyte receptor CD44 is important in tissue- specific homing by leukocytes, and overexpression of HA receptors has been correlated with tumor metastasis.
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Biomedical implants should have low density for patient comfort and high porosity and surface area to facilitate vascularization and the ingrowth of new bone. Ideally, the implant will allow sufficiently easy fluid flow for cell nutrition and osteoblast multiplication as well as migration for cellular colonization of the implant to become uniform. The pores contained within the foam's cellular matrix mimic the extracellular matrix of bone, allowing the body to fixate with the implant. The porosity of the implant also promotes apposition and facilitates vascularization−as cells are able to attach, reproduce and form basic functions.
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The porous nature of integrated implants allows fibrovascular ingrowth throughout the implant and thus also insertion of pegs or posts. Because direct mechanical coupling is thought to improve artificial eye motility, attempts have been made to develop so-called 'integrated implants' that are directly connected to the artificial eye. Historically, implants that directly attached to the prosthesis were unsuccessful because of chronic inflammation or infection arising from the exposed nonporous implant material. This led to the development of quasi- integrated implants with a specially designed anterior surface that allegedly better transferred implant motility to the artificial eye through the closed conjunctiva and Tenon's capsule.
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Hydroxyapatite implants are spherical and made in a variety of sizes and different materials (coralline / synthetic / Chinese). Since their introduction in 1989 when an implant made from hydroxyapatite received Food and Drug Administration approval, spherical hydroxyapatite implants have gained widespread popularity as an enucleation implant and was at one point the most commonly used orbital implant in the United States. The porous nature of this material allows fibrovascular ingrowth throughout the implant and permits insertion of a coupling device (PEG) with reduced risk of inflammation or infection associated with earlier types of exposed integrated implants. Hydroxyapatite is limited to preformed (stock) spheres (for enucleation) or granules (for building up defects).
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The first category of tendinopathy is paratenonitis, which refers to inflammation of the paratenon, or paratendinous sheet located between the tendon and its sheath. Tendinosis refers to non-inflammatory injury to the tendon at the cellular level. The degradation is caused by damage to collagen, cells, and the vascular components of the tendon, and is known to lead to rupture. Observations of tendons that have undergone spontaneous rupture have shown the presence of collagen fibrils that are not in the correct parallel orientation or are not uniform in length or diameter, along with rounded tenocytes, other cell abnormalities, and the ingrowth of blood vessels.
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3He is a primordial substance in the Earth's mantle, considered to have become entrapped within the Earth during planetary formation. The ratio of 3He to 4He within the Earth's crust and mantle is less than that for assumptions of solar disk composition as obtained from meteorite and lunar samples, with terrestrial materials generally containing lower 3He/4He ratios due to ingrowth of 4He from radioactive decay. 3He has a cosmological ratio of 300 atoms per million atoms of 4He (at. ppm),Wittenberg 1994 leading to the assumption that the original ratio of these primordial gases in the mantle was around 200-300 ppm when Earth was formed. A lot of 4He was generated by alpha-particle decay of uranium and thorium, and now the mantle has only around 7% primordial helium, lowering the total 3He/4He ratio to around 20 ppm.
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Typical advantages attributed to biologic meshes include reducing the risk of infection (from using non-biologic surgical meshes) and is absorbed into the resulting scar as part of cellular ingrowth. Commonly described drawbacks include the high cost of the material and its uncertain clinical effectiveness, particularly in regards to the cost. An August 2015 follow-up literature review published by the Canadian Agency for Drugs and Technologies in Health in particular addressed these drawbacks, concluding: > Based on the publications identified for the current report, there remains a > lack of sufficient evidence to guide clinical practice regarding the use of > biological mesh products ... Several surgical indications are addressed by > this collection of [randomized controlled trials (RCTs)] with relatively few > studies per indication. Therefore, it is not immediately apparent whether > this represents a significant amount of research on the clinical > effectiveness of any particular mesh product or for any specific patient > population that would support clinical decision making.
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