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Spleen Transplantation
Spleen transplantation is the transfer of spleen or its fragments from one individual to another. It is under research for induction of immunological tolerance for other transplanted organs. Success has been achieved in rodent models. Recently, evidence has been obtained for a tolerogenic effect of a spleen transplant in miniature swine. Also, the spleen harbors primitive hematopoietic progenitor cells. Spleen transplantation has been performed on humans with mixed results. __TOC__ Autotransplantation Splenic tissue can be deliberately autotransplanted after splenectomy, as some tissue will still be viable, to attempt to preserve some splenic function (with the goal of preventing OPSI). Usually this involves leaving parts of splenic parenchyma in pouches of omentum. This is not without risk or complication. This was performed after splenosis was understood; splenosis is the spontaneous reimplantation of splenic tissue elsewhere in the body (usually the abdomen) after it has bro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spleen
The spleen is an organ found in almost all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter. The word spleen comes .σπλήν Henry George Liddell, Robert Scott, ''A Greek-English Lexicon'', on Perseus Digital Library The spleen plays very important roles in regard to s (erythrocytes) and the . It removes old red blood cells and holds a reserve of blood, which can be valuable in case of |
Immunological Tolerance
Immune tolerance, or immunological tolerance, or immunotolerance, is a state of unresponsiveness of the immune system to substances or tissue that would otherwise have the capacity to elicit an immune response in a given organism. It is induced by prior exposure to that specific antigen and contrasts with conventional immune-mediated elimination of foreign antigens (see Immune response). Tolerance is classified into central tolerance or peripheral tolerance depending on where the state is originally induced—in the thymus and bone marrow (central) or in other tissues and lymph nodes (peripheral). The mechanisms by which these forms of tolerance are established are distinct, but the resulting effect is similar. Immune tolerance is important for normal physiology. Central tolerance is the main way the immune system learns to discriminate self from non-self. Peripheral tolerance is key to preventing over-reactivity of the immune system to various environmental entities (allergens, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organ Transplant
Organ transplantation is a medical procedure in which an organ is removed from one body and placed in the body of a recipient, to replace a damaged or missing organ. The donor and recipient may be at the same location, or organs may be transported from a donor site to another location. Organs and/or tissues that are transplanted within the same person's body are called autografts. Transplants that are recently performed between two subjects of the same species are called allografts. Allografts can either be from a living or cadaveric source. Organs that have been successfully transplanted include the heart, kidneys, Liver transplantation, liver, Lung transplantation, lungs, Pancreas transplantation, pancreas, Intestinal transplant, intestine, Thymus transplantation, thymus and uterus transplantation, uterus. Tissues include Bone grafting, bones, tendons (both referred to as musculoskeletal grafts), corneal transplantation, corneae, skin grafting, skin, Artificial heart valve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rodent
Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are native to all major land masses except for New Zealand, Antarctica, and several oceanic islands, though they have subsequently been introduced to most of these land masses by human activity. Rodents are extremely diverse in their ecology and lifestyles and can be found in almost every terrestrial habitat, including human-made environments. Species can be arboreal, fossorial (burrowing), saltatorial/richochetal (leaping on their hind legs), or semiaquatic. However, all rodents share several morphological features, including having only a single upper and lower pair of ever-growing incisors. Well-known rodents include mice, rats, squirrels, prairie dogs, porcupines, beavers, guinea pigs, and hamsters. Rabbits, hares, and pikas, whose i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hematopoietic Progenitor Cell
Hematopoietic stem cells (HSCs) are the stem cells that give rise to other blood cells. This process is called haematopoiesis. In vertebrates, the very first definitive HSCs arise from the ventral endothelial wall of the embryonic aorta within the (midgestational) aorta-gonad-mesonephros region, through a process known as endothelial-to-hematopoietic transition. In adults, haematopoiesis occurs in the red bone marrow, in the core of most bones. The red bone marrow is derived from the layer of the embryo called the mesoderm. Haematopoiesis is the process by which all mature blood cells are produced. It must balance enormous production needs (the average person produces more than 500 billion blood cells every day) with the need to regulate the number of each blood cell type in the circulation. In vertebrates, the vast majority of hematopoiesis occurs in the bone marrow and is derived from a limited number of hematopoietic stem cells that are multipotent and capable of extensive sel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overwhelming Post-splenectomy Infection
An overwhelming post-splenectomy infection (OPSI) is a rare but rapidly fatal infection occurring in individuals following removal (or permanent dysfunction) of the spleen. The infections are typically characterized by either meningitis or sepsis, and are caused by encapsulated organisms including ''Streptococcus pneumoniae''. It is a medical emergency and requires immediate treatment. Death has been reported to occur within 12 hours. The spleen is necessary for protection against encapsulated bacteria (see Mechanism) and as such when removed by splenectomy it can lead to rapid unchallenged infection by encapsulated bacteria. The rapid progression from mild viral symptoms to sepsis is one of the things that makes OPSI particularly dangerous. Another source of infection are species of ''Babesia'', which are tick-borne parasites that cause babesiosis. Infection with ''Capnocytophaga canimorsus'' after dog bites can also cause the condition. Signs and symptoms OPSI may initial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greater Omentum
The greater omentum (also the great omentum, omentum majus, gastrocolic omentum, epiploon, or, especially in animals, caul) is a large apron-like fold of visceral peritoneum that hangs down from the stomach. It extends from the greater curvature of the stomach, passing in front of the small intestines and doubles back to ascend to the transverse colon before reaching to the posterior abdominal wall. The greater omentum is larger than the lesser omentum, which hangs down from the liver to the lesser curvature. The common anatomical term "epiploic" derives from "epiploon", from the Greek ''epipleein'', meaning to float or sail on, since the greater omentum appears to float on the surface of the intestines. It is the first structure observed when the abdominal cavity is opened anteriorly (from the front). Structure The greater omentum is the larger of the two peritoneal folds. It consists of a double sheet of peritoneum, folded on itself so that it has four layers. The two layers o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Splenosis
Splenosis is the result of spleen tissue breaking off the main organ and implanting at another site inside the body. This is called '' heterotopic autotransplantation'' of the spleen. It most commonly occurs as a result of traumatic splenic rupture or abdominal surgery. Depending on the location of the spleen, the new piece usually implants in another part of the abdominal cavity (including the pelvic cavity). Single case reports also describe splenosis in the thoracic cavity, in subcutaneous tissue, in the liver or in the cranial cavity. Splenosis must be distinguished from the presence of additional spleens, which are innate and are the result of differences in embryological development. Additionally, splenosis must be differentiated from malignant tumors which may look similar when imaged.R. D. Fremont, T. W. Rice: ''Splenosis: A Review.'' History Ectopic splenic tissue was first described in 1896 by Albrecht in Germany, whereas the term “splenosis” was first used by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scintigraphy
Scintigraphy (from Latin ''scintilla'', "spark"), also known as a gamma scan, is a diagnostic test in nuclear medicine, where radioisotopes attached to drugs that travel to a specific organ or tissue (radiopharmaceuticals) are taken internally and the emitted gamma radiation is captured by external detectors (gamma cameras) to form two-dimensional images in a similar process to the capture of x-ray images. In contrast, SPECT and ''positron emission tomography'' (PET) form 3-dimensional images and are therefore classified as separate techniques from scintigraphy, although they also use gamma cameras to detect internal radiation. Scintigraphy is unlike a diagnostic X-ray where external radiation is passed through the body to form an image. Process Scintillography is an imaging method of nuclear events provoked by collisions or charged current interactions among nuclear particles or ionizing radiation and atoms which result in a brief, localised pulse of electromagnetic radiation, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blood Film
A blood smear, peripheral blood smear or blood film is a thin layer of blood smeared on a glass microscope slide and then stained in such a way as to allow the various blood cells to be examined microscopically. Blood smears are examined in the investigation of hematological (blood) disorders and are routinely employed to look for blood parasites, such as those of malaria and filariasis. Preparation A blood smear is made by placing a drop of blood on one end of a slide, and using a ''spreader slide'' to disperse the blood over the slide's length. The aim is to get a region, called a monolayer, where the cells are spaced far enough apart to be counted and differentiated. The monolayer is found in the "feathered edge" created by the spreader slide as it draws the blood forward. The slide is left to air dry, after which the blood is fixed to the slide by immersing it briefly in methanol. The fixative is essential for good staining and presentation of cellular detail. After fixat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lymphatic Organ Surgery
Lymph (from Latin, , meaning "water") is the fluid that flows through the lymphatic system, a system composed of lymph vessels (channels) and intervening lymph nodes whose function, like the venous system, is to return fluid from the tissues to be recirculated. At the origin of the fluid-return process, interstitial fluid—the fluid between the cells in all body tissues—enters the lymph capillaries. This lymphatic fluid is then transported via progressively larger lymphatic vessels through lymph nodes, where substances are removed by tissue lymphocytes and circulating lymphocytes are added to the fluid, before emptying ultimately into the right or the left subclavian vein, where it mixes with central venous blood. Because it is derived from interstitial fluid, with which blood and surrounding cells continually exchange substances, lymph undergoes continual change in composition. It is generally similar to blood plasma, which is the fluid component of blood. Lymph returns prote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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