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Biomedical subjects

E G Barton

Publications and source records attributed to E G Barton.

7 recordsLinked to original sources
PubMed1995

AquaLite bioluminescence assay of thyrotropin in serum evaluated.

We studied a new commercially available thyrotropin (TSH) assay, the AquaLite Bioluminescence TSH-Immunoassay (SeaLite Inc.). This assay has a detection limit of 0.005 mIU/L and a functional sensitivity of 0.017 mIU/L and meets the requirements of a third-generation TSH assay. Using this assay, we measured serum TSH in 153 euthyroid individuals and in the following patients: 32 primary hypothyroids; 38 primary hyperthyroids; 35 with thyroid cancer receiving suppressive therapy with levothyroxine (L-T4); 33 receiving replacement L-T4 aimed at reaching and maintaining a euthyroid status; 23 with subclinical hyperthyroidism; and 52 hospitalized for nonthyroidal illnesses (NTI). The AquaLite TSH assay perfectly discriminated hypothyroid and untreated hyperthyroid patients from euthyroid subjects and clearly discriminated between overtly and mildly hyperthyroid patients. Intermethod comparisons showed that the AquaLite and the Nichols assays were more effective than the ACS-180 and the TOSOH assays in discriminating among hyperthyroid patients, including patients over-treated with L-T4.

Adult↗
PubMed1989

Four sensitive thyrotropin assays critically evaluated and compared.

We compared four sensitive procedures for thyrotropin (TSH)--Corning's Magic-Lite, ElectroNucleonics' Delfia, Baxter's Stratus, Nichols' Allegro--for their ability to completely discriminate TSH concentrations in sera in euthyroidism, hyperthyroidism, and hypothyroidism. We evaluated the analytical and clinical performance of these procedures according to previously published criteria. All procedures we examined fulfilled the criterion stipulating less than 1% overlap between the assay variation at the lower normal range limit and the assay sensitivity. Both measurements were made with an interassay CV not exceeding 10% to 15%. All procedures produced results that correlated well for specimens with TSH concentrations of greater than 0.4 milli-int. unit/L, and all four procedures clearly distinguished hypothyroid from euthyroid subjects. In a hyperthyroid-euthyroid comparison, three of the procedures, the Magic-Lite, Delfia, and Allegro, differentiated the two with 97% accuracy, the Stratus procedure with only 90% accuracy. The procedures appeared to differ even more in the measurement of TSH in serum of patients undergoing suppressive treatment with thyroid hormones and in hospitalized nonthyroidally ill patients. The observed differences among procedures were thought to be related in part to a matrix serum effect, which is accentuated in samples from hospitalized patients.

Evaluation Studies as Topic↗
PubMed1983

A "column-batch" method for separating MB and LD1 in a single fraction.

In this "column-batch" method for separating the MB and BB isoenzymes of creatine kinase and the LD1 isoenzyme of lactate dehydrogenase, one can, alternatively, separate MB from BB or obtain a combined fraction containing MB, BB, and LD1. The principal advantage is that the resulting fractions are twofold as concentrated as was the applied sample. Thus, activity can be measured by conventional automated methods, with no need for the modifications to compensate for diluted fractions that are required by other ion-exchange methods. Another advantage is the total absence of interference by the MM isoenzyme. A strong anion exchanger (AG-MP1, Bio-Rad) is used in the acetate form at pH 6.3. There is no retention of MM; retained MB, BB, and LD1 are eluted with a solution of magnesium acetate. Results are compared with those obtained for subunit B and LD1 by immunoinhibition. Results with patients are considered consistent with myocardial infarction if MB exceeds 20 U/L and 3% of the total CK and LD1 exceeds 130 U/L or 28% of the total LD activity.

Chromatography, Ion Exchange↗