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Ligand Binding Assay
A ligand binding assay (LBA) is an assay, or an analytic procedure, which relies on the binding of ligand molecules to receptors, antibodies or other macromolecules. A detection method is used to determine the presence and extent of the ligand-receptor complexes formed, and this is usually determined electrochemically or through a fluorescence detection method. This type of analytic test can be used to test for the presence of target molecules in a sample that are known to bind to the receptor. There are numerous types of ligand binding assays, both radioactive and non-radioactive.Joseph R. Lakowicz. (1991) Topics in Fluorescence Spectroscopy: Biochemical applications. As such, ligand binding assays are a superset of radiobinding assays, which are the conceptual inverse of radioimmunoassays (RIA). Some newer types are called "mix-and-measure" assays because they do not require separation of bound from unbound ligand. Ligand binding assays are used primarily in pharmacology to pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 qu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medication
A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy ( pharmacotherapy) is an important part of the medical field and relies on the science of pharmacology for continual advancement and on pharmacy for appropriate management. Drugs are classified in multiple ways. One of the key divisions is by level of control, which distinguishes prescription drugs (those that a pharmacist dispenses only on the order of a physician, physician assistant, or qualified nurse) from over-the-counter drugs (those that consumers can order for themselves). Another key distinction is between traditional small molecule drugs, usually derived from chemical synthesis, and biopharmaceuticals, which include recombinant proteins, vaccines, blood products used therapeutically (such as IVIG), gene therapy, monoclonal antibodies and cell therapy (for instance, stem cell th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Specific Activity
Specific activity is the activity per unit mass of a radionuclide and is a physical property of that radionuclide. Activity is a quantity (for which the SI unit is the becquerel) related to radioactivity, and is defined as the number of radioactive transformations per second that occur in a particular radionuclide. The unit of activity is the becquerel (Bq), which is defined as one radioactive decay per second. The older, non-SI unit of activity is the curie (Ci), which is radioactive decay per second. Another unit of activity is the Rutherford, which is defined as radioactive decay per second. Since the probability of radioactive decay for a given radionuclide within a set time interval is fixed (with some slight exceptions, see changing decay rates), the number of decays that occur in a given time of a given mass (and hence a specific number of atoms) of that radionuclide is also a fixed (ignoring statistical fluctuations). Thus, specific activity is defined as the acti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioligand
A radioligand is a radioactive biochemical substance (in particular, a ligand (biochemistry), ligand that is radioactive tracer, radiolabeled) that is used for diagnosis or for research-oriented study of the receptor (biochemistry), receptor systems of the body. In a neuroimaging application the radioligand is injected into the pertinent tissue, or infused into the bloodstream. It binds to its receptor (biochemistry), receptor. When the radioactive isotope in the ligand decays it can be measured by positron emission tomography (PET) or single-photon emission computed tomography (SPECT). In ''in vivo'' systems it is often used to quantify the binding of a test molecule to the binding site of a radioligand. The higher the affinity of the molecule the more radioligand is displaced from the binding site and the increasing radioactive decay can be measured by scintillography. This assay is commonly used to calculate the binding constant of molecules to receptors. The transport of the r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Receptor Cloning
Receptor may refer to: * Sensory receptor, in physiology, any structure which, on receiving environmental stimuli, produces an informative nerve impulse *Receptor (biochemistry), in biochemistry, a protein molecule that receives and responds to a neurotransmitter, or other substance **Cell surface receptor Cell surface receptors (membrane receptors, transmembrane receptors) are receptors that are embedded in the plasma membrane of cells. They act in cell signaling by receiving (binding to) extracellular molecules. They are specialized integral m ..., a receptor on the outer surface of a cell membrane, that takes part in communication between the cell and the outside world ** Nuclear receptor, a receptor found within cells that is responsible for sensing steroid and thyroid hormones and certain other molecules ** Immune receptor, a receptor that occurs on the surface of immunocytes and binds to antigens * Receiver (radio), a device for the reception of electromagnetic signa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homogeneity And Heterogeneity
Homogeneity and heterogeneity are concepts often used in the sciences and statistics relating to the uniformity of a substance or organism. A material or image that is homogeneous is uniform in composition or character (i.e. color, shape, size, weight, height, distribution, texture, language, income, disease, temperature, radioactivity, architectural design, etc.); one that is heterogeneous is distinctly nonuniform in at least one of these qualities. Heterogeneous Mixtures, in chemistry, is where certain elements are unwillingly combined and, when given the option, will separate. Etymology and spelling The words ''homogeneous'' and ''heterogeneous'' come from Medieval Latin ''homogeneus'' and ''heterogeneus'', from Ancient Greek ὁμογενής (''homogenēs'') and ἑτερογενής (''heterogenēs''), from ὁμός (''homos'', “same”) and ἕτερος (''heteros'', “other, another, different”) respectively, followed by γένος (''genos'', “kind”); - ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equilibrium Constant
The equilibrium constant of a chemical reaction is the value of its reaction quotient at chemical equilibrium, a state approached by a dynamic chemical system after sufficient time has elapsed at which its composition has no measurable tendency towards further change. For a given set of reaction conditions, the equilibrium constant is independent of the initial analytical concentrations of the reactant and product species in the mixture. Thus, given the initial composition of a system, known equilibrium constant values can be used to determine the composition of the system at equilibrium. However, reaction parameters like temperature, solvent, and ionic strength may all influence the value of the equilibrium constant. A knowledge of equilibrium constants is essential for the understanding of many chemical systems, as well as biochemical processes such as oxygen transport by hemoglobin in blood and acid–base homeostasis in the human body. Stability constants, formation c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioactive Ligand Binding Assays
Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is considered radioactive. Three of the most common types of decay are alpha decay ( ), beta decay ( ), and gamma decay ( ), all of which involve emitting one or more particles. The weak force is the mechanism that is responsible for beta decay, while the other two are governed by the electromagnetism and nuclear force. A fourth type of common decay is electron capture, in which an unstable nucleus captures an inner electron from one of the electron shells. The loss of that electron from the shell results in a cascade of electrons dropping down to that lower shell resulting in emission of discrete X-rays from the transitions. A common example is iodine-125 commonly used in medical settings. Radioactive decay is a stochastic (i.e. random) proc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Affinity Laws
The affinity laws (also known as the "Fan Laws" or "Pump Laws") for pumps/fans are used in hydraulics, hydronics and/or HVAC to express the relationship between variables involved in pump or fan performance (such as head, volumetric flow rate, shaft speed) and power. They apply to pumps, fans, and hydraulic turbines. In these rotary implements, the affinity laws apply both to centrifugal and axial flows. The laws are derived using the Buckingham π theorem. The affinity laws are useful as they allow prediction of the head discharge characteristic of a pump or fan from a known characteristic measured at a different speed or impeller diameter. The only requirement is that the two pumps or fans are dynamically similar, that is, the ratios of the fluid forced are the same. It is also required that the two impellers' speed or diameter are running at the same efficiency. Law 1. With impeller diameter (D) held constant: Law 1a. Flow is proportional to shaft speed: : = Law 1b. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solomon Berson
Solomon Aaron Berson (April 22, 1918 – April 11, 1972) was an American physician and scientist whose discoveries, mostly together with Rosalyn Yalow, caused major advances in clinical biochemistry.Rall JE. ''Solomon A. Berson''. In "Biographical Memoirs". National Academy of Sciences 1990;59:54-71. Fulltext Five years after Berson's death, Yalow received a Nobel Prize, which cannot be awarded posthumously, for their joint work on the radioimmunoassay. Biography Early life Born in New York City, Berson was a keen musician and chess player. He graduated from the City College of New York in 1938. After failing to obtain a place in medical school he earned an MSc (1939) and an anatomy instructorship at New York University before finally securing a place in NYU medical school in 1941. He completed his degree (Alpha Omega Alpha) in 1945, and after internships in Boston and two years in the army he returned to New York to do an internal medicine residency at the Bronx Veterans Ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rosalyn Sussman Yalow
Rosalyn Sussman Yalow (July 19, 1921 – May 30, 2011) was an American medical physicist, and a co-winner of the 1977 Nobel Prize in Physiology or Medicine (together with Roger Guillemin and Andrew Schally) for development of the radioimmunoassay technique. She was the second woman (after Gerty Cori), and the first American-born woman, to be awarded the Nobel Prize in Physiology or Medicine. Biography Childhood Rosalyn Sussman Yalow was born in the Bronx, New York, the daughter of Clara (née Zipper) and Simon Sussman, and was raised in a Jewish household. She went to Walton High School (Bronx), New York City. After high school, she attended the all-female, tuition-free Hunter College, where her mother hoped she would learn to become a teacher. Instead, Yalow decided to study physics. College Yalow knew how to type, and was able to get a part-time position as a secretary to Dr. Rudolf Schoenheimer, a leading biochemist at Columbia University's College of Physicians and Surgeons. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
