|
Thymic Hyperplasia
Thymus hyperplasia refers to an enlargement (" hyperplasia") of the thymus. It is not always a disease state. The size of the thymus usually peaks during adolescence and atrophies in the following decades. Before the immune function of the thymus was well understood, the enlargement was sometimes seen as a cause for alarm, and justification for surgical reduction. This approach is much less common today. It can be associated with myasthenia gravis. Magnetic resonance imaging can be used to distinguish it from thymoma. Thymic hyperplasia Thymic hyperplasia can be divided into three groups namely, those without any pre-existing medical condition, those recovering from a pre-existing medical condition such as pneumonia, corticosteroid therapy, radiation therapy, chemotherapy, surgery, and burns, and those with other disorders such as hyperthyroidism, sarcoidosis, or pure red cell aplasia Pure red cell aplasia (PRCA) or erythroblastopenia refers to a type of aplastic anemia affec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperplasia
Hyperplasia (from ancient Greek ὑπέρ ''huper'' 'over' + πλάσις ''plasis'' 'formation'), or hypergenesis, is an enlargement of an organ or tissue caused by an increase in the amount of organic tissue that results from cell proliferation. It may lead to the gross enlargement of an organ, and the term is sometimes confused with benign neoplasia or benign tumor. Hyperplasia is a common preneoplastic response to stimulus. Microscopically, cells resemble normal cells but are increased in numbers. Sometimes cells may also be increased in size ( hypertrophy). Hyperplasia is different from hypertrophy in that the adaptive cell change in hypertrophy is an increase in the ''size'' of cells, whereas hyperplasia involves an increase in the ''number'' of cells. Causes Hyperplasia may be due to any number of causes, including proliferation of basal layer of epidermis to compensate skin loss, chronic inflammatory response, hormonal dysfunctions, or compensation for damage ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thymus
The thymus is a specialized primary lymphoid organ of the immune system. Within the thymus, thymus cell lymphocytes or ''T cells'' mature. T cells are critical to the adaptive immune system, where the body adapts to specific foreign invaders. The thymus is located in the upper front part of the chest, in the anterior superior mediastinum, behind the sternum, and in front of the heart. It is made up of two lobes, each consisting of a central medulla and an outer cortex, surrounded by a capsule. The thymus is made up of immature T cells called thymocytes, as well as lining cells called epithelial cells which help the thymocytes develop. T cells that successfully develop react appropriately with MHC immune receptors of the body (called ''positive selection'') and not against proteins of the body (called ''negative selection''). The thymus is largest and most active during the neonatal and pre-adolescent periods. By the early teens, the thymus begins to decrease in size and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myasthenia Gravis
Myasthenia gravis (MG) is a long-term neuromuscular junction disease that leads to varying degrees of skeletal muscle weakness. The most commonly affected muscles are those of the eyes, face, and swallowing. It can result in double vision, drooping eyelids, trouble talking, and trouble walking. Onset can be sudden. Those affected often have a large thymus or develop a thymoma. Myasthenia gravis is an autoimmune disease of the neuro-muscular junction which results from antibodies that block or destroy nicotinic acetylcholine receptors (AChR) at the junction between the nerve and muscle. This prevents nerve impulses from triggering muscle contractions. Most cases are due to immunoglobulin G1 (IgG1) and IgG3 antibodies that attack AChR in the postsynaptic membrane, causing complement-mediated damage and muscle weakness. Rarely, an inherited genetic defect in the neuromuscular junction results in a similar condition known as congenital myasthenia. Babies of mothers with myas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Electric
General Electric Company (GE) is an American multinational conglomerate founded in 1892, and incorporated in New York state and headquartered in Boston. The company operated in sectors including healthcare, aviation, power, renewable energy, digital industry, additive manufacturing and venture capital and finance, but has since divested from several areas, now primarily consisting of the first four segments. In 2020, GE ranked among the Fortune 500 as the 33rd largest firm in the United States by gross revenue. In 2011, GE ranked among the Fortune 20 as the 14th most profitable company, but later very severely underperformed the market (by about 75%) as its profitability collapsed. Two employees of GE – Irving Langmuir (1932) and Ivar Giaever (1973) – have been awarded the Nobel Prize. On November 9, 2021, the company announced it would divide itself into three investment-grade public companies. On July 18, 2022, GE unveiled the brand names of the companies it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Resonance Imaging
Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to generate images of the organs in the body. MRI does not involve X-rays or the use of ionizing radiation, which distinguishes it from CT and PET scans. MRI is a medical application of nuclear magnetic resonance (NMR) which can also be used for imaging in other NMR applications, such as NMR spectroscopy. MRI is widely used in hospitals and clinics for medical diagnosis, staging and follow-up of disease. Compared to CT, MRI provides better contrast in images of soft-tissues, e.g. in the brain or abdomen. However, it may be perceived as less comfortable by patients, due to the usually longer and louder measurements with the subject in a long, confining tube, though "Open" MRI designs mostly relieve this. Additionally, implants and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thymoma
A thymoma is a tumor originating from the epithelial cells of the thymus that is considered a rare malignancy. Thymomas are frequently associated with neuromuscular disorders such as myasthenia gravis; thymoma is found in 20% of patients with myasthenia gravis. Once diagnosed, thymomas may be removed surgically. In the rare case of a malignant tumor, chemotherapy may be used. Signs and symptoms A third of all people with a thymoma have symptoms caused by compression of the surrounding organs by an expansive mass. These problems may take the form of superior vena cava syndrome, dysphagia (difficulty swallowing), cough, or chest pain. One-third of patients have their tumors discovered because they have an associated autoimmune disorder. As mentioned earlier, the most common of those conditions is myasthenia gravis (MG); 10–15% of patients with MG have a thymoma and, conversely, 30–45% of patients with thymomas have MG. Additional associated autoimmune conditions include th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sarcoidosis
Sarcoidosis (also known as ''Besnier-Boeck-Schaumann disease'') is a disease involving abnormal collections of inflammatory cells that form lumps known as granulomata. The disease usually begins in the lungs, skin, or lymph nodes. Less commonly affected are the eyes, liver, heart, and brain. Any organ can be affected though. The signs and symptoms depend on the organ involved. Often, no, or only mild, symptoms are seen. When it affects the lungs, wheezing, coughing, shortness of breath, or chest pain may occur. Some may have Löfgren syndrome with fever, large lymph nodes, arthritis, and a rash known as erythema nodosum. The cause of sarcoidosis is unknown. Some believe it may be due to an immune reaction to a trigger such as an infection or chemicals in those who are genetically predisposed. Those with affected family members are at greater risk. Diagnosis is partly based on signs and symptoms, which may be supported by biopsy. Findings that make it likely include large ly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pure Red Cell Aplasia
Pure red cell aplasia (PRCA) or erythroblastopenia refers to a type of aplastic anemia affecting the precursors to red blood cells but usually not to white blood cells. In PRCA, the bone marrow ceases to produce red blood cells. There are multiple etiologies that can cause PRCA. The condition has been first described by Paul Kaznelson in 1922. Signs and symptoms Signs and symptoms may include: * Pale appearance * Rapid heart rate * Fatigue Causes Causes of PRCA include: Treatment PRCA is considered an autoimmune disease as it will respond to immunosuppressant treatment such as cyclosporin in many patients, though this approach is not without risk. It has also been shown to respond to treatments with rituximab and tacrolimus. See also * Diamond–Blackfan anemia (genetic red cell aplasia) * Aplastic anemia Aplastic anemia is a cancer in which the body fails to make blood cells in sufficient numbers. Blood cells are produced in the bone marrow by stem cells that resid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
