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Biomedical subjects

F W Spierto

Publications and source records attributed to F W Spierto.

29 records · Page 2Linked to original sources
PubMed1976

An evaluation of three commercially prepared anion-exchange resin columns for separation of tetraiodothryonine in serum.

Three different commercially prepared anion-exchange resin columns for thyroxine (T4) separation from serum for the "T4 by column" assay were evaluated using the protocol of the supplier. The claims by the suppliers for the distribution and recovery of T4 in the first and second thyroxine-containing eluates were experimentally evaluated by the addition of a tracer quantity of purified [125I]T4. The average experimentally determined elution ratios of recoverable T4 (sum of T4 in first and second eluates) with these commercial columns were: Bio-Rad, 92.2:7.8 (90:10 claimed); Oxford, 87.8:12.2 (94:6 claimed); and Curtis Nuclear, 88.7:11.3 (80:20 claimed). The percent recoveries of T4 in the first thyroxine-containing eluate were: Oxford, 82.3 + 9.70 (x +/- 1 S.D.); Bio-Rad, 91.75 +/- 2.09; and Curtis Nuclear, 74.20 +/- 6.14. Mean serum T4 values obtained by the column method with all commercial columns tested were lower than competitive protein binding radio-assay (CPBR) values if the former values were not corrected for recovery. When individual recovery correction factors were applied to column results, improved correlation and better correspondence of "T4 by column" mean values with the CPBR values were noted. It is concluded that the largest part of the total variability of the "T4 by column" assay is contributed by the chromatographic step when the colorimetric step is performed with an automated technique.

Anion Exchange Resins↗
PubMed1976

Interference of fatty acids in the competitive protein-binding assay for serum thyroxine.

An increase in apparent thyroxine values obtained by competitive protein-binding assay on storage of sera is well documented. We find that the major source of this positive bias is probably the unsaturated nonesterified fatty acids. Nonesterified fatty acids cause a positive basis in the competitive protein-binding assay for serum thyroxine because they inhibit the binding of radioactive thyroxine by the serum-binding reagent (probably thyroxine-binding globulin). This inhibition by fatty acids may be due to the formation of a fatty acid/thyroxine complex. The degree of inhibition caused by the fatty acids depends on the length of the carbon chain of the fatty acid and the degree of saturation. Short-chain fatty acids are more potent inhibitors of thyroxine binding than those with a longer chain, and unsaturated fatty acids are more potent inhibitors of thyroxine binding than are saturated fatty acids. The polyunsaturated fatty acid, arachidonic acid, was the most potent inhibitor of all the fatty acids tested. Triglycerides (triacylglycerols) insignificantly inhibit thyroxine binding in this assay.

Binding, Competitive↗
PubMedDate not supplied

Urinary porphyrins in children exposed transplacentally to polyhalogenated aromatics in Taiwan.

In 1979, there was a large (greater than 2,000 cases) outbreak of poisoning due to contaminated rice oil in central Taiwan. The causal agent was a mixture of thermally degraded polychlorinated biphenyls (PCBs), polychlorinated quaterphenyls, and polychlorinated dibenzofurans, which had become mixed with the oil during processing. Patients remained symptomatic for several years afterward, and the chemicals persisted in their tissue. Women who became pregnant had children with high perinatal mortality and a dysmorphic syndrome. We examined urines from 75 children born to exposed mothers after the oil was confiscated, 74 controls, and 12 sibs of the exposed children. Four of the transplacentally exposed children, 2 controls, and 1 sib had a type B hepatic porphyria (i.e., uroporphyrin greater than coproporphyrin); total porphyrin excretion was elevated in the exposed children as a group (95 vs. 81 micrograms/L); and 8 of the 75 exposed children and 2 controls had total urinary porphyrin concentrations of greater than 200 micrograms/L.

Albuminuria↗
PubMedDate not supplied

Development and evaluation of a microtiter plate enzyme immunoassay for antibodies to 3,3'-dichlorobenzidine.

The authors obtained and evaluated antisera from rabbits injected with a derivative of a potent bladder carcinogen, dichlorobenzidine (DCB), conjugated to bovine serum albumin (BSA). A 14C-radioimmunoassay (RIA) was able to detect the presence of DCB antibodies, but its relative insensitivity led to the development of a more sensitive enzyme immunoassay (EIA). The EIA test was a "sandwich" method in which a second antibody, labeled with an enzyme (horseradish peroxidase), was used to measure antibody binding to transferrin (Tf)-conjugated DCB immobilized on a microtiter plate. Antibody titers measured by RIA were approximately 1:40; when measured by EIA, they were approximately 1:40,000. Antibody specificity was assessed by comparing the antibody binding activities of DCB, BSA, Tf, BSA-conjugated to DCB, and a number of N-substituted aromatic compounds that included benzidine (Bz). Among the compounds tested, the rabbit antiserum reacted only with DCB and the carrier protein, BSA. Moreover, antibody binding activity to Tf-conjugated DCB was significantly inhibited by unconjugated DCB concentrations between 30 and 500 ng/mL. The precision of antibody binding activities as a function of DCB concentration (expressed by the CV) ranged from 9% for low (30 ng/mL) DCB levels to 12% for higher (500 ng/mL) levels. This evaluation suggests that the antiserum obtained would be appropriate for detecting DCB levels at the ng/mL level.

3,3'-Dichlorobenzidine↗