Melisa Acevedo
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Melisa Acevedo
MELISA (Memory Lymphocyte Immunostimulation Assay) is a blood test that detects type IV hypersensitivity to metals, chemicals, environmental toxins and molds. Type IV hypersensitivity reactions, particularly to nickel, are well established and may affect 20% of the population.Silverberg N, Pelletier J, Jacob S, Schneider L. Nickel allergic contact dermatitis: identification, treatment, and prevention. Pediatrics 2020; 145. https://doi.org/10.1542/peds.2020-0628. Mechanism The MELISA test measures type-IV delayed hypersensitivity reaction. Type-IV reactions are mediated by T-lymphocytes (or memory lymphocytes) that have had prior contact with a given allergen.Stejskal V, Forsbeck M, Nilsson R. Lymphocyte transformation test for diagnosis of isothiazolinone allergy in man. J Invest Dermatol 1990; 94: 798–802. This is in contrast to a type-I allergy, which is mediated by IgE antibodies and is often tested using an ELISA test. In genetically predisposed individuals, an ongoing ex ...
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Type IV Hypersensitivity
Type IV hypersensitivity, often called delayed-type hypersensitivity, is a type of hypersensitivity reaction that can take a day or more to develop. Unlike the other types, it is not humoral (not antibody-mediated) but rather is a type of cell-mediated response. This response involves the interaction of T cells, monocytes, and macrophages. This reaction is caused when CD4+ Th1 cells recognize foreign antigen in a complex with the MHC class II on the surface of antigen-presenting cells. These can be macrophages that secrete IL-12, which stimulates the proliferation of further CD4+ Th1 cells. CD4+ T cells secrete IL-2 and interferon gamma (IFNγ), inducing the further release of other Th1 cytokines, thus mediating the immune response. Activated CD8+ T cells destroy target cells on contact, whereas activated macrophages produce hydrolytic enzymes and, on presentation with certain intracellular pathogens, transform into multinucleated giant cells. The over ...
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T-lymphocyte
A T cell is a type of lymphocyte. T cells are one of the important white blood cells of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell receptor (TCR) on their cell surface. T cells are born from hematopoietic stem cells, found in the bone marrow. Developing T cells then migrate to the thymus gland to develop (or mature). T cells derive their name from the thymus. After migration to the thymus, the precursor cells mature into several distinct types of T cells. T cell differentiation also continues after they have left the thymus. Groups of specific, differentiated T cell subtypes have a variety of important functions in controlling and shaping the immune response. One of these functions is immune-mediated cell death, and it is carried out by two major subtypes: CD8+ "killer" and CD4+ "helper" T cells. (These are named for the presence of the cell surface proteins CD8 or C ...
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Antibody
An antibody (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein used by the immune system to identify and neutralize foreign objects such as pathogenic bacteria and viruses. The antibody recognizes a unique molecule of the pathogen, called an antigen. Each tip of the "Y" of an antibody contains a paratope (analogous to a lock) that is specific for one particular epitope (analogous to a key) on an antigen, allowing these two structures to bind together with precision. Using this binding mechanism, an antibody can ''tag'' a microbe or an infected cell for attack by other parts of the immune system, or can neutralize it directly (for example, by blocking a part of a virus that is essential for its invasion). To allow the immune system to recognize millions of different antigens, the antigen-binding sites at both tips of the antibody come in an equally wide variety. In contrast, the remainder of the antibody is relatively constant. It only occurs in a few varia ...
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ELISA
The enzyme-linked immunosorbent assay (ELISA) (, ) is a commonly used analytical biochemistry assay, first described by Eva Engvall and Peter Perlmann in 1971. The assay uses a solid-phase type of enzyme immunoassay (EIA) to detect the presence of a ligand (commonly a protein) in a liquid sample using antibodies directed against the protein to be measured. ELISA has been used as a diagnostic tool in medicine, plant pathology, and biotechnology, as well as a quality control check in various industries. In the most simple form of an ELISA, antigens from the sample to be tested are attached to a surface. Then, a matching antibody is applied over the surface so it can bind the antigen. This antibody is linked to an enzyme and then any unbound antibodies are removed. In the final step, a substance containing the enzyme's substrate is added. If there was binding, the subsequent reaction produces a detectable signal, most commonly a color change. Performing an ELISA involves at least ...
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Assay
An assay is an investigative (analytic) procedure in laboratory medicine, mining, pharmacology, environmental biology and molecular biology for qualitatively assessing or quantitatively measuring the presence, amount, or functional activity of a target entity. The measured entity is often called the analyte, the measurand, or the target of the assay. The analyte can be a drug, biochemical substance, chemical element or compound, or cell in an organism or organic sample. An assay usually aims to measure an analyte's intensive property and express it in the relevant measurement unit (e.g. molarity, density, functional activity in enzyme international units, degree of effect in comparison to a standard, etc.). If the assay involves exogenous reactants (the reagents), then their quantities are kept fixed (or in excess) so that the quantity and quality of the target are the only limiting factors. The difference in the assay outcome is used to deduce the unknown quality or quantity o ...
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Pokeweed
''Phytolacca americana'', also known as American pokeweed, pokeweed, poke sallet, dragonberries, and inkberry, is a poisonous, herbaceous perennial plant in the pokeweed family Phytolaccaceae. This pokeweed grows . It has simple leaves on green to red or purplish stems and a large white taproot. The flowers are green to white, followed by berries which ripen through red to purple to almost black which are a food source for songbirds such as gray catbird, northern mockingbird, northern cardinal, and brown thrasher, as well as other birds and some small non-avian animals (i.e., for species that are unaffected by its mammalian toxins). Pokeweed is native to eastern North America, the Midwest, and the South, with more scattered populations in the far West. It is also naturalized in parts of Europe and Asia. It is considered a pest species by farmers. Pokeweed is poisonous to humans, dogs, and livestock. In spring and early summer, shoots and leaves (not the root) are edible with pro ...
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Isotope
Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numbers) due to different numbers of neutrons in their nuclei. While all isotopes of a given element have almost the same chemical properties, they have different atomic masses and physical properties. The term isotope is formed from the Greek roots isos ( ἴσος "equal") and topos ( τόπος "place"), meaning "the same place"; thus, the meaning behind the name is that different isotopes of a single element occupy the same position on the periodic table. It was coined by Scottish doctor and writer Margaret Todd in 1913 in a suggestion to the British chemist Frederick Soddy. The number of protons within the atom's nucleus is called its atomic number and is equal to the number of electrons in the neutral (non-ionized) atom. Each atomic numbe ...
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Berylliosis
Berylliosis, or chronic beryllium disease (CBD), is a chronic allergic-type lung response and chronic lung disease caused by exposure to beryllium and its compounds, a form of beryllium poisoning. It is distinct from acute beryllium poisoning, which became rare following occupational exposure limits established around 1950. Berylliosis is an occupational lung disease. While there is no cure, symptoms can be treated. Signs and symptoms With single or prolonged exposure by inhalation the lungs may become sensitized to beryllium. Berylliosis has a slow onset and progression. Some people who are sensitized to beryllium may not have symptoms.OSHBeryllium Health EffectsPage accessed March 29, 2016 Continued exposure causes the development of small inflammatory nodules, called granulomas. Of note, the authors of a 2006 study suggested that beryllium inhalation was not the only form of exposure and perhaps skin exposure was also a cause, as they found that a reduction in beryllium inhalat ...
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Chronic Fatigue Syndrome
Chronic fatigue syndrome (CFS), also called myalgic encephalomyelitis (ME) or ME/CFS, is a complex, debilitating, long-term medical condition. The causes and mechanisms of the disease are not fully understood. Distinguishing core symptoms are lengthy exacerbations or flare-ups of the illness following ordinary minor physical or mental activity, known as post-exertional malaise (PEM); greatly diminished capacity to accomplish tasks that were routine before the illness; and sleep disturbances. Orthostatic intolerance (difficulty sitting and standing upright) and cognitive dysfunction are also diagnostic. Frequently and variably, other common symptoms occur involving numerous body systems, and chronic pain is common. The unexplained and often incapacitating fatigue in CFS is different from that caused by normal strenuous ongoing exertion, is not significantly relieved by rest, and is not due to a previous medical condition. Diagnosis is based on the person's symptoms because no c ...
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Chronic Fatigue Syndrome
Chronic fatigue syndrome (CFS), also called myalgic encephalomyelitis (ME) or ME/CFS, is a complex, debilitating, long-term medical condition. The causes and mechanisms of the disease are not fully understood. Distinguishing core symptoms are lengthy exacerbations or flare-ups of the illness following ordinary minor physical or mental activity, known as post-exertional malaise (PEM); greatly diminished capacity to accomplish tasks that were routine before the illness; and sleep disturbances. Orthostatic intolerance (difficulty sitting and standing upright) and cognitive dysfunction are also diagnostic. Frequently and variably, other common symptoms occur involving numerous body systems, and chronic pain is common. The unexplained and often incapacitating fatigue in CFS is different from that caused by normal strenuous ongoing exertion, is not significantly relieved by rest, and is not due to a previous medical condition. Diagnosis is based on the person's symptoms because no c ...
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Multiple Sclerosis
Multiple (cerebral) sclerosis (MS), also known as encephalomyelitis disseminata or disseminated sclerosis, is the most common demyelinating disease, in which the insulating covers of nerve cells in the brain and spinal cord are damaged. This damage disrupts the ability of parts of the nervous system to transmit signals, resulting in a range of signs and symptoms, including physical, mental, and sometimes psychiatric problems. Specific symptoms can include double vision, blindness in one eye, muscle weakness, and trouble with sensation or coordination. MS takes several forms, with new symptoms either occurring in isolated attacks (relapsing forms) or building up over time (progressive forms). In the relapsing forms of MS, between attacks, symptoms may disappear completely, although some permanent neurological problems often remain, especially as the disease advances. While the cause is unclear, the underlying mechanism is thought to be either destruction by the immune system ...
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HPA Axis
HPA may refer to: Organizations * Harry Potter Alliance, a charity * Halifax Port Authority, Canada * Hamburg Port Authority, Germany * Hawaii Preparatory Academy, a school in Hawaii, US * Health Protection Agency, UK * Heerespersonalamt, the German Army Personnel Agency 1920-1944 * Hollywood Post Alliance, an American trade organization * Houston Peace Academy of the Islamic Education Institute of Texas, US * Hurlingham Polo Association, UK polo governing body * HPA Toucan human-powered aircraft built by Hertfordshire Pedal Aeronauts People *Hans Peter Anvin (born 1972), Swedish computer programmer *Howlin' Pelle Almqvist (Born 1978), Swedish lead singer of garage rock band The Hives Science * Hectopascal (hPa), a unit of pressure * Human platelet antigen * Human Protein Atlas * Hydrogen pinch analysis * Hypothalamic–pituitary–adrenal axis in physiology Technology *High-performance addressing, in LCD displays *Host protected area of computer data storage *Human-powered ...
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