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Tissue Engineering Of Heart Valves
Tissue engineered heart valves (TEHV) offer a new and advancing proposed treatment of creating a living heart valve for people who are in need of either a full or partial heart valve replacement. Currently, there are over a quarter of a million prosthetic heart valves implanted annually, and the number of patients requiring replacement surgeries is only suspected to rise and even triple over the next fifty years. While current treatments offered such as mechanical valves or biological valves are not deleterious to one's health, they both have their own limitations in that mechanical valves necessitate the lifelong use of anticoagulants while biological valves are susceptible to structural degradation and reoperation. Thus, ''in situ'' (in its original position or place) tissue engineering of heart valves serves as a novel approach that explores the use creating a living heart valve composed of the host's own cells that is capable of growing, adapting, and interacting within the huma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heart Valve Replacement
Valve replacement surgery is the replacement of one or more of the heart valves with either an artificial heart valve or a bioprosthesis ( homograft from human tissue or xenograft e.g. from pig). It is an alternative to valve repair. __TOC__ Procedures There are four procedures * Aortic valve replacement * Mitral valve replacement Mitral valve replacement is a procedure whereby the diseased mitral valve of a patient's heart is replaced by either a mechanical or tissue (bioprosthetic) valve. The mitral valve may need to be replaced because: * The valve is leaky ( mitral va ... * Tricuspid valve replacement * Pulmonary valve replacement Current aortic valve replacement approaches include closed heart surgery, Very invasive cardiac surgery (VICS) and Very invasive, Scapulae-based aortic valve replacement. Catheter replacement of the aortic valve (called trans-aortic valve replacement or implementation AVR or TAVI is a minimally invasive option for those suffering from aortic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibroblast
A fibroblast is a type of biological cell that synthesizes the extracellular matrix and collagen, produces the structural framework ( stroma) for animal tissues, and plays a critical role in wound healing. Fibroblasts are the most common cells of connective tissue in animals. Structure Fibroblasts have a branched cytoplasm surrounding an elliptical, speckled nucleus having two or more nucleoli. Active fibroblasts can be recognized by their abundant rough endoplasmic reticulum. Inactive fibroblasts (called fibrocytes) are smaller, spindle-shaped, and have a reduced amount of rough endoplasmic reticulum. Although disjointed and scattered when they have to cover a large space, fibroblasts, when crowded, often locally align in parallel clusters. Unlike the epithelial cells lining the body structures, fibroblasts do not form flat monolayers and are not restricted by a polarizing attachment to a basal lamina on one side, although they may contribute to basal lamina components in so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ross Procedure
The Ross procedure, also known as pulmonary autograft, is a heart valve replacement operation to treat severe aortic valve disease, such as in children and young adults with a bicuspid aortic valve. It involves removing the diseased aortic valve, situated at the exit of the left side of the heart (where the aorta begins), and replacing it with the person's own healthy pulmonary valve (autograft), removed from the exit of the heart's right side (where the pulmonary artery begins). To reconstruct the right sided exit, a pulmonary valve from a cadaver (homograft), or a stentless xenograft, is used to replace the removed pulmonary valve. Compared to a mechanical valve replacement, it avoids the requirement for thinning the blood, has favourable blood flow dynamics, allows growth of the valve with growth of the child and has less risk of endocarditis. It is not performed in Marfan syndrome, if pulmonary valve disease, or if immune problems like lupus. Other contraindications in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biodegradability
Biodegradation is the breakdown of organic matter by microorganisms, such as bacteria and fungi. It is generally assumed to be a natural process, which differentiates it from composting. Composting is a human-driven process in which biodegradation occurs under a specific set of circumstances. The process of biodegradation is threefold: first an object undergoes biodeterioration, which is the mechanical weakening of its structure; then follows biofragmentation, which is the breakdown of materials by microorganisms; and finally assimilation, which is the incorporation of the old material into new cells. In practice, almost all chemical compounds and materials are subject to biodegradation, the key element being time. Things like vegetables may degrade within days, while glass and some plastics take many millennia to decompose. A standard for biodegradability used by the European Union is that greater than 90% of the original material must be converted into , water and minerals by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diagram Of The Human Heart (cropped)
A diagram is a symbolic representation of information using visualization techniques. Diagrams have been used since prehistoric times on walls of caves, but became more prevalent during the Enlightenment. Sometimes, the technique uses a three-dimensional visualization which is then projected onto a two-dimensional surface. The word ''graph'' is sometimes used as a synonym for diagram. Overview The term "diagram" in its commonly used sense can have a general or specific meaning: * ''visual information device'' : Like the term "illustration", "diagram" is used as a collective term standing for the whole class of technical genres, including graphs, technical drawings and tables. * ''specific kind of visual display'' : This is the genre that shows qualitative data with shapes that are connected by lines, arrows, or other visual links. In science the term is used in both ways. For example, Anderson (1997) stated more generally: "diagrams are pictorial, yet abstract, representati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foreign-body Giant Cell
A foreign-body giant cell is a collection of fused macrophages (giant cell) which are generated in response to the presence of a large foreign body. This is particularly evident with catheters, parasites, or biomaterials that are inserted into the body for replacement or regeneration of diseased or damaged tissues. Foreign body giant cells are also produced to digest foreign material that is too large for phagocytosis. The inflammatory process that creates these cells often leads to a foreign body granuloma. The human body goes through several steps when exposed to foreign biomaterial including acute and chronic inflammation, and formation of new tissue and a fibrous capsule along the surface of the implantation. Foreign body reactions, which are a type of chronic inflammation, are characterized by the presence of macrophages, monocytes, and foreign-body giant cells (FBGCs). The response of the foreign body reaction determines how compatible the implanted material will be in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reverse Transcription Polymerase Chain Reaction
Reverse transcription polymerase chain reaction (RT-PCR) is a laboratory technique combining reverse transcription of RNA into DNA (in this context called complementary DNA or cDNA) and amplification of specific DNA targets using polymerase chain reaction (PCR). It is primarily used to measure the amount of a specific RNA. This is achieved by monitoring the amplification reaction using fluorescence, a technique called real-time PCR or quantitative PCR (qPCR). Combined RT-PCR and qPCR are routinely used for analysis of gene expression and quantification of viral RNA in research and clinical settings. The close association between RT-PCR and qPCR has led to metonymic use of the term qPCR to mean RT-PCR. Such use may be confusing, as RT-PCR can be used without qPCR, for example to enable molecular cloning, sequencing or simple detection of RNA. Conversely, qPCR may be used without RT-PCR, for example to quantify the copy number of a specific piece of DNA. Nomenclature The combin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foreign Body Reaction
A foreign body reaction (FBR) is a typical tissue response to a foreign body within biological tissue. It usually includes the formation of a foreign body granuloma. Tissue-encapsulation of an implant is an example, as is inflammation around a splinter. Foreign body granuloma formation consists of protein adsorption, macrophages, multinucleated foreign body giant cells (macrophage fusion), fibroblasts, and angiogenesis. It has also been proposed that the mechanical property of the interface between an implant and its surrounding tissues is critical for the host response. In the long term, the foreign body reaction results in encapsulation of the foreign body within a calcified shell. For example, a '' lithopedion'' is a rare phenomenon which occurs most commonly when a fetus dies during an abdominal pregnancy, is too large to be reabsorbed by the body, and calcifies. Foreign body reaction to biomaterial implantation Following biomaterial implantation, blood and body fluids ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Suture Micrograph
Suture, literally meaning "seam", may refer to: Arts, entertainment, and media * ''Suture'' (album), a 2000 album by American Industrial rock band Chemlab * ''Suture'' (film), a 1993 film directed by Scott McGehee and David Siegel * Suture (band), an early 1990s band with Kathleen Hanna, Sharon Cheslow, and Doug Birdzell Healthcare * Suture (anatomy), a rigid joint between hard parts of animals ** Suture (joint), concerning the major joints in the bones of the cranium ** Ammonitic suture, the intersection of the septum with the outer shell in Ammonites ** Facial suture (trilobite), divisions in the cephalon (head) of most trilobites, along which the exoskeleton splits during molting * Surgical suture A surgical suture, also known as a stitch or stitches, is a medical device used to hold body tissues together and approximate wound edges after an injury or surgery. Application generally involves using a needle with an attached length of threa ..., a stitch used by doctors a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcification
Calcification is the accumulation of calcium salts in a body tissue. It normally occurs in the formation of bone, but calcium can be deposited abnormally in soft tissue,Miller, J. D. Cardiovascular calcification: Orbicular origins. ''Nature Materials'' 12, 476-478 (2013). causing it to harden. Calcifications may be classified on whether there is mineral balance or not, and the location of the calcification. Calcification may also refer to the processes of normal mineral deposition in biological systems, such as the formation of stromatolites or mollusc shells (see Biomineralization). Signs and symptoms Calcification can manifest itself in many ways in the body depending on the location. In the pulpal structure of a tooth, calcification often presents asymptomatically, and is diagnosed as an incidental finding during radiographic interpretation. Individual teeth with calcified pulp will typically respond negatively to vitality testing; teeth with calcified pulp often lack ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrophage
Macrophages (abbreviated as M φ, MΦ or MP) ( el, large eaters, from Greek ''μακρός'' (') = large, ''φαγεῖν'' (') = to eat) are a type of white blood cell of the immune system that engulfs and digests pathogens, such as cancer cells, microbe A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...s, cellular debris, and foreign substances, which do not have proteins that are specific to healthy body cells on their surface. The process is called phagocytosis, which acts to defend the host against infection and injury. These large phagocytes are found in essentially all tissues, where they patrol for potential pathogens by amoeboid movement. They take various forms (with various names) throughout the body (e.g., histiocytes, Kupffer cells, alveolar macrophages, microg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chronic Inflammation
Chronic systemic inflammation (SI) is the result of release of pro-inflammatory cytokines from immune-related cells and the chronic activation of the innate immune system. It can contribute to the development or progression of certain conditions such as cardiovascular disease, cancer, diabetes mellitus, chronic kidney disease, non-alcoholic fatty liver disease, autoimmune and neurodegenerative disorders, and coronary heart disease. Mechanisms Release of pro-inflammatory cytokines and activation of the innate immune system may be the result of either external (biological or chemical agents) or internal (genetic mutations/variations) factors. The cytokine Interleukin 6 and C-reactive protein are common inflammatory markers used to diagnose systemic inflammation risk. Baseline C-reactive protein levels deviate due to natural genetic variation, but significant increases can result from risk factors such as smoking, obesity, lifestyle, and high blood pressure. Systemic chronic inflam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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