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Biomedical subjects

G H Thorpe

Publications and source records attributed to G H Thorpe.

49 records · Page 3Linked to original sources
PubMed1985

Enhancement of the horseradish peroxidase-catalyzed chemiluminescent oxidation of cyclic diacyl hydrazides by 6-hydroxybenzothiazoles.

6-Hydroxybenzothiazole, 2-cyano-6-hydroxybenzothiazole, and 2-(6-hydroxy-2-benzothiazolyl)thiazole-4-carboxylic acid (dehydroluciferin) dramatically enhance light emission from the horseradish peroxidase conjugate catalyzed oxidation of luminol, isoluminol, N-(6-aminobutyl)-N-ethyl isoluminol, and 7-dimethylaminonaphthalene-1,2-dicarboxylic acid hydrazide by either peroxide or perborate. Light emission is enhanced by up to 1000-fold, which is an improvement over the enhancement previously observed using firefly luciferin (4,5-dihydro-2-(6-hydroxy-2-benzothiazolyl)thiazole-4-carboxylic acid). Enhancement is influenced by enhancer concentration and pH. Spectral scans of light emitted in enhanced and unenhanced reactions are similar, suggesting that aminophthalate products, and not the enhancers, are the emitters.

Catalysis↗
PubMed1985

A rapid chemiluminescent enzyme-linked immunosorbent assay for cytomegalovirus immunoglobulin G antibodies using instant photographic film.

A rapid and convenient chemiluminescent enzyme-linked immunosorbent assay (ELISA) for IgG antibodies to cytomegalovirus has been developed which uses low cost equipment. Assays were carried out on transparent microtitre plates and used an anti-human IgG horseradish peroxidase conjugate. Bound peroxidase was detected chemiluminescently using a p-iodophenol-luminol-peroxide reagent. Light emission from the wells of the microtitre plate was detected on instant photographic film (ASA 20,000) held in a specially designed shutter type camera. The semi-quantitative technique was tested in a routine laboratory for a period of 7 wk and the results obtained compared well (95.3% agreement) with those obtained by a conventional colorimetric ELISA using an alkaline phosphatase label.

Antibodies, Viral↗
PubMed1985

Enhanced luminescence enzyme immunoassay for factor VIII related antigen.

A sandwich enzyme immunoassay for plasma factor VIII related antigen has been developed which exploits a para-iodophenol enhanced chemiluminescent reaction to detect the horseradish peroxidase label. The assay entailed 15 min incubations with sample and with conjugate and had a detection limit of 0.12 mU. It showed good within batch precision (coefficient of variation = 2.95-5.8%) and results on a series of 57 specimens agreed with results obtained by immunoelectrophoresis (correlation coefficient = 0.97).

Antigens↗
PubMed1985

Phenols as enhancers of the chemiluminescent horseradish peroxidase-luminol-hydrogen peroxide reaction: application in luminescence-monitored enzyme immunoassays.

Certain phenol derivatives, including p-iodophenol and p-phenylphenol, enhance light emission from the horseradish peroxidase-catalyzed oxidation of cyclic diacyl hydrazides such as luminol. The light emission decays slowly (glowing for several minutes) and its intensity may be greater than 1000-fold that of the unenhanced reaction. The enhanced system enables rapid, sensitive assay of peroxidase conjugates. We describe its application in immunoassays for human choriogonadotropin, digoxin, and factor VIII-related antigen. Luminescent quantification of peroxidase labels has been directly incorporated into immunoassays based on beads, tubes, or microtiter plates, used in conjunction with photodetectors such as photomultiplier tubes or instant photographic film. Enhancement with phenol derivatives exceeds that achieved with 6-hydroxybenzothiazole derivatives and depends on pH and enhancer concentration. Emission spectra of phenol-enhanced and unenhanced reactions are remarkably similar, suggesting that the enhancers do not act as more efficient emitters but exert their action earlier in the complex reaction between peroxidase, oxidant, and luminol.

Antigens↗
PubMed1984

Enhanced luminescent enzyme immunoassays for rubella antibody, immunoglobulin E and digoxin.

A novel firefly luciferin- enhanced luminescent procedure for the quantitation of horseradish peroxidase labels has been directly incorporated into established enzyme immunoassays. The procedure is rapid and sensitive and uses readily available reagents. Light emission from the enhanced reaction is high and relatively constant and thus easily measured. The luminescence procedure has been successfully incorporated into immunometric assays for rubella antibody and human IgE and into a competitive immunoassay for digoxin.

Animals↗
PubMed1984

An enhanced chemiluminescence enzyme immunoassay for serum progesterone.

A competitive enhanced luminescent enzyme immunoassay for serum progesterone is described, which is based on a 11 alpha-hydroxyprogesterone 11-hemisuccinyl-horseradish peroxidase conjugate and a black polystyrene microtitre plate sensitised with anti-progesterone IgG. Bound label was determined using a mixture of 4-iodophenol, luminol and peroxide, and the light emitted from the wells of the plate quantitated using a luminescent plate reader. The assay was sensitive (detection limit 0.5 pg), precise (CV 2.7 - 9.0% in the concentration range 4.3-67.7 nM) and showed good correlation (r = 0.99) with a conventional radioimmunoassay.

Horseradish Peroxidase↗
PubMed1979

Analytical luminescence: its potential in the clinical laboratory.

The various types of chemiluminescent and bioluminescent reactions are described. Applications of luminescence in the analysis of substancs of clinical interest are surveyed. The advantages, disadvantages, and prospects for luminescent assays are discussed.

Adenosine Triphosphate↗
PubMedDate not supplied

Enhanced chemiluminescent immunoassay for aldosterone.

A solid phase immunoassay for aldosterone using enhanced chemiluminescent detection has been developed. Monoclonal antibodies against aldosterone were used for the immune reaction and compared with polyclonal antibodies. Uniform Protein A coated polystyrene tubes were used as solid phase for the monoclonal antibody and second (anti-rabbit) antibody coated tubes for the polyclonal antibody. Horseradish peroxidase was covalently linked to aldosterone as enzyme label. Optimum conditions were established for the generation and measurement of the luminescent reactions using luminol, p-iodophenol as enhancer and hydrogen peroxide. The advantages of this assay are the high sensitivity with a detection limit of 100 fg/tube, the prolonged luminescence signal with a simplification of the measurement (simpler detectors, external start pipetting) and the short measure time with the possibility of repeated measurement. The coefficients of variation were 4.2%-7.3% in the concentration range 140-1180 pmol/l. The assay showed a significant correlation (r = 0.91) with the ELISA. The aldosterone concentrations in plasma and saliva of patients with Conn's syndrome were significantly increased, and in patients with Addison's disease were found near the detection limit.

Aldosterone↗
PubMedDate not supplied

Influence of different luminols on the characteristics of the chemiluminescence reaction in human neutrophils.

In search for a luminol with very high output of light, 20 different luminol samples were tested for their ability to enhance the chemiluminescence reaction in phorbol myristate acetate activated human neutrophils. We found that the majority of luminols tested (17 samples) gave almost the same light output from neutrophils, and that the major part of the activity was from an intracellular origin. Owing to the fact that three isoluminol samples were unable to monitor respiratory burst activity taking place intracellularly, a very low level of chemiluminescence was obtained with these samples. Their light output was, however, greatly increased when horseradish peroxidase or myeloperoxidase was added, showing that the light-generating reaction with isoluminol as well as with luminol is peroxidase-dependent. The fact that isoluminol could also use myeloperoxidase as amplifying peroxidase, suggests that that the lack of measurable intracellular activity in the presence of isoluminol is somehow related to a limited or restricted diffusion of the molecule to intracellular sites. The isoluminol system constitutes a sensitive system for measuring release of oxygen metabolites from phagocytic cells.

Adult↗