Anaphylaxis is a serious, potentially fatal allergic reaction and medical emergency that is rapid in onset and requires immediate medical attention regardless of use of emergency medication on site. It typically causes more than one of the following: an itchy rash, throat closing due to swelling that can obstruct or stop breathing; severe tongue swelling that can also interfere with or stop breathing; shortness of breath, vomiting, lightheadedness, loss of consciousness, low blood pressure, and medical shock. These symptoms typically start in minutes to hours and then increase very rapidly to life-threatening levels. Urgent medical treatment is required to prevent serious harm and death, even if the patient has used an epipen or has taken other medications in response, and even if symptoms appear to be improving.
In molecular biology and biotechnology, a fluorescent tag, also known as a fluorescent label or fluorescent probe, is a molecule that is attached chemically to aid in the detection of a biomolecule such as a protein, antibody, or amino acid. Generally, fluorescent tagging, or labeling, uses a reactive derivative of a fluorescent molecule known as a fluorophore. The fluorophore selectively binds to a specific region or functional group on the target molecule and can be attached chemically or biologically. Various labeling techniques such as enzymatic labeling, protein labeling, and genetic labeling are widely utilized. Ethidium bromide, fluorescein and green fluorescent protein are common tags. The most commonly labelled molecules are antibodies, proteins, amino acids and peptides which are then used as specific probes for detection of a particular target.
Angiography or arteriography is a medical imaging technique used to visualize the inside, or lumen, of blood vessels and organs of the body, with particular interest in the arteries, veins, and the heart chambers. Modern angiography is performed by injecting a radio-opaque contrast agent into the blood vessel and imaging using X-ray based techniques such as fluoroscopy.
A fluorophore is a fluorescent chemical compound that can re-emit light upon light excitation. Fluorophores typically contain several combined aromatic groups, or planar or cyclic molecules with several π bonds.
Fluorescein angiography (FA), fluorescent angiography (FAG), or fundus fluorescein angiography (FFA) is a technique for examining the circulation of the retina and choroid using a fluorescent dye and a specialized camera. Sodium fluorescein is added into the systemic circulation, the retina is illuminated with blue light at a wavelength of 490 nanometers, and an angiogram is obtained by photographing the fluorescent green light that is emitted by the dye. The fluorescein is administered intravenously in intravenous fluorescein angiography (IVFA) and orally in oral fluorescein angiography (OFA). The test is a dye tracing method.
Rhodamine is a family of related dyes, a subset of the triarylmethane dyes. They are derivatives of xanthene. Important members of the rhodamine family are Rhodamine 6G, Rhodamine 123, and Rhodamine B. They are mainly used to dye paper and inks, but they lack the lightfastness for fabric dyeing.
Iodinated contrast is a form of water-soluble, intravenous radiocontrast agent containing iodine, which enhances the visibility of vascular structures and organs during radiographic procedures. Some pathologies, such as cancer, have particularly improved visibility with iodinated contrast.
The Alexa Fluor family of fluorescent dyes is a series of dyes invented by Molecular Probes, now a part of Thermo Fisher Scientific, and sold under the Invitrogen brand name. Alexa Fluor dyes are frequently used as cell and tissue labels in fluorescence microscopy and cell biology. Alexa Fluor dyes can be conjugated directly to primary antibodies or to secondary antibodies to amplify signal and sensitivity or other biomolecules.
Fluorescein isothiocyanate (FITC) is a derivative of fluorescein used in wide-ranging applications including flow cytometry. First described in 1942, FITC is the original fluorescein molecule functionalized with an isothiocyanate reactive group (−N=C=S), replacing a hydrogen atom on the bottom ring of the structure. It is typically available as a mixture of isomers, fluorescein 5-isothiocyanate (5-FITC) and fluorescein 6-isothiocyanate (6-FITC). FITC is reactive towards nucleophiles including amine and sulfhydryl groups on proteins. It was synthesized by Robert Seiwald and Joseph Burckhalter in 1958.
Texas Red or sulforhodamine 101 acid chloride is a red fluorescent dye, used in histology for staining cell specimens, for sorting cells with fluorescent-activated cell sorting machines, in fluorescence microscopy applications, and in immunohistochemistry. Texas Red fluoresces at about 615 nm, and the peak of its absorption spectrum is at 589 nm. The powder is dark purple. Solutions can be excited by a dye laser tuned to 595-605 nm, or less efficiently a krypton laser at 567 nm. The absorption extinction coefficient at 596 nm is about 85,000 M−1cm−1.
IAEDANS is an organic fluorophore. It stands for 5-({2-[ amino]ethyl}amino)naphthalene-1-sulfonic acid. It is widely used as a marker in fluorescence spectroscopy.
Rhodamine B is a chemical compound and a dye. It is often used as a tracer dye within water to determine the rate and direction of flow and transport. Rhodamine dyes fluoresce and can thus be detected easily and inexpensively with fluorometers.
Molecular beacons, or molecular beacon probes, are oligonucleotide hybridization probes that can report the presence of specific nucleic acids in homogenous solutions. Molecular beacons are hairpin-shaped molecules with an internally quenched fluorophore whose fluorescence is restored when they bind to a target nucleic acid sequence. This is a novel non-radioactive method for detecting specific sequences of nucleic acids. They are useful in situations where it is either not possible or desirable to isolate the probe-target hybrids from an excess of the hybridization probes.
Rose bengal (4,5,6,7-tetrachloro-2',4',5',7'-tetraiodofluorescein) is a stain. Rose bengal belongs to the class of organic compounds called xanthenes. Its sodium salt is commonly used in eye drops to stain damaged conjunctival and corneal cells and thereby identify damage to the eye. The stain is also used in the preparation of Foraminifera for microscopic analysis, allowing the distinction between forms that were alive or dead at the time of collection.
6-Carboxyfluorescein (6-FAM) is a fluorescent dye with an absorption wavelength of 495 nm and an emission wavelength of 517 nm. A carboxyfluorescein molecule is a fluorescein molecule with a carboxyl group added. They are commonly used as a tracer agents. It is used in the sequencing of nucleic acids and in the labeling of nucleotides.
Dye tracing is a method of tracking and tracing various flows using dye as a flow tracer when added to a liquid. Dye tracing may be used to analyse the flow of the liquid or the transport of objects within the liquid. Dye tracking may be either qualitative, showing the presence of a particular flow, or quantitative, when the amount of the traced dye is measured by special instruments.
The DyLight Fluor family of fluorescent dyes are produced by Dyomics in collaboration with Thermo Fisher Scientific. DyLight dyes are typically used in biotechnology and research applications as biomolecule, cell and tissue labels for fluorescence microscopy, cell biology or molecular biology.
BODIPY is the technical common name of a chemical compound with formula C
9H
7BN
2F
2, whose molecule consists of a boron difluoride group BF
2 joined to a dipyrromethene group C
9H
7N
2; specifically, the compound 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene in the IUPAC nomenclature. The common name is an abbreviation for "boron-dipyrromethene". It is a red crystalline solid, stable at ambient temperature, soluble in methanol.
Indocyanine green (ICG) is a cyanine dye used in medical diagnostics. It is used for determining cardiac output, hepatic function, liver and gastric blood flow, and for ophthalmic and cerebral angiography. It has a peak spectral absorption at about 800 nm. These infrared frequencies penetrate retinal layers, allowing ICG angiography to image deeper patterns of circulation than fluorescein angiography. ICG binds tightly to plasma proteins and becomes confined to the vascular system. ICG has a half-life of 150 to 180 seconds and is removed from circulation exclusively by the liver to bile.
Fluorescence polarization immunoassay (FPIA) is a class of in vitro biochemical test used for rapid detection of antibody or antigen in sample. FPIA is a competitive homogenous assay, that consists of a simple prepare and read method, without the requirement of separation or washing steps.
