α-Ketoglutaric acid is a dicarboxylic acid, i.e., a short-chain fatty acid containing two carboxyl groups with C, O, and H standing for carbon, oxygen, and hydrogen, respectively. However, almost all animal tissues and extracellular fluids have a pH above 7. At these basic pH levels α-ketoglutaric acid exists almost exclusively as its conjugate base. That is, it has two negative electric charges due to its release of positively charged hydrogen from both of its now negatively charged carboxy groups, CO−2. This double negatively charge molecule is referred to as α-ketoglutarate or 2-oxoglutarate.
Cytotoxicity is the quality of being toxic to cells. Examples of toxic agents are toxic metals, toxic chemicals, microbe neurotoxins, radiation particles and even specific neurotransmitters when the system is out of balance. Also some types of venom, e.g. from the puff adder or brown recluse spider are toxic to cells.
Chronic granulomatous disease (CGD), also known as Bridges–Good syndrome, chronic granulomatous disorder, and Quie syndrome, is a diverse group of hereditary diseases in which certain cells of the immune system have difficulty forming the reactive oxygen compounds used to kill certain ingested pathogens. This leads to the formation of granulomas in many organs. CGD affects about 1 in 200,000 people in the United States, with about 20 new cases diagnosed each year.
Creatine kinase (CK), also known as creatine phosphokinase (CPK) or phosphocreatine kinase, is an enzyme expressed by various tissues and cell types. CK catalyses the conversion of creatine and uses adenosine triphosphate (ATP) to create phosphocreatine (PCr) and adenosine diphosphate (ADP). This CK enzyme reaction is reversible and thus ATP can be generated from PCr and ADP.
The MTT assay is a colorimetric assay for assessing cell metabolic activity. NAD(P)H-dependent cellular oxidoreductase enzymes may, under defined conditions, reflect the number of viable cells present. These enzymes are capable of reducing the tetrazolium dye MTT, which is chemically 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, to its insoluble formazan, which has a purple color. Other closely related tetrazolium dyes including XTT, MTS and the WSTs, are used in conjunction with the intermediate electron acceptor, 1-methoxy phenazine methosulfate (PMS). With WST-1, which is cell-impermeable, reduction occurs outside the cell via plasma membrane electron transport. However, this traditionally assumed explanation is currently contended as proof has also been found of MTT reduction to formazan in lipidic cellular structures without apparent involvement of oxidoreductases.
In biochemistry, isozymes are enzymes that differ in amino acid sequence but catalyze the same chemical reaction. Isozymes usually have different kinetic parameters, or are regulated differently. They permit the fine-tuning of metabolism to meet the particular needs of a given tissue or developmental stage.
Inborn errors of metabolism form a large class of genetic diseases involving congenital disorders of enzyme activities. The majority are due to defects of single genes that code for enzymes that facilitate conversion of various substances (substrates) into others (products). In most of the disorders, problems arise due to accumulation of substances which are toxic or interfere with normal function, or due to the effects of reduced ability to synthesize essential compounds. Inborn errors of metabolism are often referred to as congenital metabolic diseases or inherited metabolic disorders. Another term used to describe these disorders is "enzymopathies". This term was created following the study of biodynamic enzymology, a science based on the study of the enzymes and their products. Finally, inborn errors of metabolism were studied for the first time by British physician Archibald Garrod (1857–1936), in 1908. He is known for work that prefigured the "one gene-one enzyme" hypothesis, based on his studies on the nature and inheritance of alkaptonuria. His seminal text, Inborn Errors of Metabolism, was published in 1923.
A vital stain in a casual usage may mean a stain that can be applied on living cells without killing them. Vital stains have been useful for diagnostic and surgical techniques in a variety of medical specialties. In supravital staining, living cells have been removed from an organism, whereas intravital staining is done by injecting or otherwise introducing the stain into the body. The term vital stain is used by some authors to refer to an intravital stain, and by others interchangeably with a supravital stain, the core concept being that the cell being examined is still alive. In a more strict sense, the term vital staining has a meaning contrasting with supravital staining. While in supravital staining the living cells take up the stain, in "vital staining" – the most accepted but apparently paradoxical meaning of this term, the living cells exclude the stain i.e. stain negatively and only the dead cells stain positively and thus viability can be assessed by counting the percentage of total cells that stain negatively. Very bulky or highly charged stains that don't cross live plasma membrane are used as vital stains and supravital stains are those that are either small or are pumped actively into live cells. Since supravital and intravital nature of the staining depends on the dye, a combination of supravital and vital dyes can also be used in a sophisticated way to better classify cells into distinct subsets.
Nitro blue tetrazolium is a chemical compound composed of two tetrazole moieties. It is used in immunology for sensitive detection of alkaline phosphatase. NBT serves as the oxidant and BCIP is the AP-substrate.
Seed testing is an analysis of seeds for viability. Seed testing performed for a number of reasons, including research purposes or to determine if seed storage techniques are functioning. There are four tests most commonly done. The first two listed below are common for scientific research.
Neutral red is a eurhodin dye used for staining in histology. It stains lysosomes red. It is used as a general stain in histology, as a counterstain in combination with other dyes, and for many staining methods. Together with Janus Green B, it is used to stain embryonal tissues and supravital staining of blood. Can be used for staining Golgi apparatus in cells and Nissl granules in neurons.
11β-Hydroxysteroid dehydrogenase type 1, also known as cortisone reductase, is an NADPH-dependent enzyme highly expressed in key metabolic tissues including liver, adipose tissue, and the central nervous system. In these tissues, HSD11B1 reduces cortisone to the active hormone cortisol that activates glucocorticoid receptors. It belongs to the family of short-chain dehydrogenases. It is encoded by the HSD11B1 gene.
The formazans are compounds of the general formula [R-N=N-C(R')=N-NH-R"], formally derivatives of formazan [H2NN=CHN=NH], unknown in free form.
Lactate dehydrogenase (LDH or LD) is an enzyme found in nearly all living cells. LDH catalyzes the conversion of pyruvate to lactate and back, as it converts NAD+ to NADH and back. A dehydrogenase is an enzyme that transfers a hydride from one molecule to another.
Resazurin is a phenoxazine dye that is weakly fluorescent, nontoxic, cell-permeable, and redox‐sensitive. Resazurin has a blue to purple color above pH 6.5 and an orange color below pH 3.8. It is used in microbiological, cellular, and enzymatic assays because it can be irreversibly reduced to the pink-colored and highly fluorescent resorufin (7-Hydroxy-3H-phenoxazin-3-one). At circum-neutral pH, resorufin can be detected by visual observation of its pink color or by fluorimetry, with an excitation maximum at 530-570 nm and an emission maximum at 580-590 nm.
A viability assay is an assay that is created to determine the ability of organs, cells or tissues to maintain or recover a state of survival. Viability can be distinguished from the all-or-nothing states of life and death by the use of a quantifiable index that ranges between the integers of 0 and 1 or, if more easily understood, the range of 0% and 100%. Viability can be observed through the physical properties of cells, tissues, and organs. Some of these include mechanical activity, motility, such as with spermatozoa and granulocytes, the contraction of muscle tissue or cells, mitotic activity in cellular functions, and more. Viability assays provide a more precise basis for measurement of an organism's level of vitality.
A diagnosis of myocardial infarction is created by integrating the history of the presenting illness and physical examination with electrocardiogram findings and cardiac markers. A coronary angiogram allows visualization of narrowings or obstructions on the heart vessels, and therapeutic measures can follow immediately. At autopsy, a pathologist can diagnose a myocardial infarction based on anatomopathological findings.
INT is a commonly used tetrazolium salt, similar to tetrazolium chloride that on reduction produces a red formazan dye that can be used for quantitative redox assays. It is also toxic to prokaryotes.
Nicotinamide riboside (NR, SR647) is a pyridine-nucleoside and a form of vitamin B3. It functions as a precursor to nicotinamide adenine dinucleotide, or NAD+, through a two-step and a three-step pathway.
