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Biomedical subjects

L J Kricka

Publications and source records attributed to L J Kricka.

At least 91 records · Page 5Linked to original sources
PubMed1986

An enhanced chemiluminescent enzyme immunoassay for serum carcinoembryonic antigen based on a modification of a commercial kit.

A conventional colorimetric peroxidase end-point (ortho-phenylenediamine substrate), used in an enzyme immunoassay for carcinoembryonic antigen, employing plastic beads as solid support, has been replaced by a much faster (30 seconds versus 30 minutes) enhanced chemiluminescent assay for the peroxidase label. Para-iodophenol was used to enhance the light emission from the peroxidase catalysed chemiluminescent reaction between luminol and hydrogen peroxide. Values for precision and carcinoembryonic antigen concentration obtained with the chemiluminescent and colorimetric versions of the immunoassay on 62 serum specimens were in good agreement.

Carcinoembryonic Antigen↗
PubMed1986

Enhanced chemiluminescent reactions catalyzed by horseradish peroxidase.

Enhancement of light emission from the horseradish peroxidase-catalyzed oxidation of diacyl hydrazides on addition of 6-hydroxybenzothiazole or phenol derivatives forms the basis of rapid, specific, and sensitive chemiluminescent assays for peroxidase. The advantages and wide applicability of the technique have been demonstrated in a range of ligand-binding assays. Careful selection of chemiluminescent reagents, enhancer, their relative proportions and reaction conditions, and more detailed knowledge of the mechanism of enhancement should enable further improvements in sensitivity and the intensity or constancy of light emission.

Digoxin↗
PubMed1986

Enhanced luminescent quantitation of horseradish peroxidase conjugates: application in an enzyme immunoassay for digoxin.

A p-iodophenol-enhanced luminescent end-point has been incorporated into a commercially available heterogeneous competitive enzyme immunoassay for digoxin based on a horseradish peroxidase-digoxin conjugate. The luminescent end-point could be completed in less than 1 min and significantly reduced overall assay time. Results for the assay obtained using enhanced luminescence showed good agreement with those obtained using a colorimetric end-point (correlation coefficient 0.98). Both assays gave acceptable precision within the therapeutic range. The incubation time for the luminescent immunoassay was reduced to 15 min and still gave differentiation between sub-therapeutic, therapeutic and toxic levels of digoxin.

Colorimetry↗
PubMed1986

Red cell morphology in alcoholics: a new test for alcohol abuse.

Scanning electron microscopy has shown that the blood of alcoholics contains a large number of morphologically abnormal red cells. In two groups of alcoholics, the number of morphologically abnormal red cells ranged from 23.1% to 89.3% and 27.4% to 57.3% of total red cells compared to values in healthy controls of 4.5%-12.6% and 27.7%-79.5% in nonalcoholic liver disease patients. A characteristic finding was the presence of triangulocytes: these ranged from 1.2% to 18.0% of total red cells in the alcoholics as compared to 0-0.5% in healthy controls, and 0-1.3% in patients with nonalcoholic liver disease. The presence of elevated numbers of triangulocytes in blood appears to be specific to alcohol abuse. It is not, for example, elevated in nonalcoholic liver disease. No correlation was found between the number of triangulocytes or the number of morphologically abnormal red cells in blood and either the duration of alcohol abuse or the amount of alcohol consumed. Both parameters tended, however, to return to normal values during withdrawal. The mechanism by which alcohol abuse causes the morphologic abnormalities is not known. Preliminary in vitro experiments indicate that it is unlikely to arise as an effect of alcohol on circulating red cells. Based on the data presented, the measurement of the number of triangulocytes in a blood sample, although slow and laborious, may provide a highly specific test for alcohol abuse.

Acetaldehyde↗
PubMed1985

Enhanced chemiluminescent method for the detection of DNA dot-hybridization assays.

A simple enhanced chemiluminescent procedure for the quantitation of DNA hybridization to dot blots is described. The method utilizes DNA probes labeled with biotin, which are detected using a biotinylated streptavidin-horseradish peroxidase complex. The peroxidase enzyme then takes part in an enhanced chemiluminescent reaction with luminol, peroxide, and an enhancer. The method can be used to give quantitative results using a photomultiplier tube or qualitative results by recording the light emission on instant photographic film.

Bacterial Proteins↗
PubMed1985

A rapid luminescently monitored enzyme immunoassay for IgE.

A novel halophenol-enhanced luminol-peroxide luminescent detection method for horseradish peroxidase has been tested in an enzyme immunoassay for IgE. The luminescent enzyme immunoassay was reproducible (within-batch CV, 3.9-13.2%) and values obtained on serum samples showed good agreement with those obtained by colorimetric enzyme immunoassay. The major advantages of the luminescent detection method are that it is rapid, 30 s compared with 30 min for the colorimetric assay using o-phenylenediamine, and the luminescent signal is intense and stable for several minutes.

Colorimetry↗
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↗