A 125I-radioimmunoassay for diethylstilbestrol in serum of patients with prostatic cancer treated with stilphostrol.
A new radioimmunoassay for determining diethylstilbestrol in serum using N-(4'-OH-[3'-125I]iodophenethyl)-6-(4-O-diethylstilbestryl)-hex anamide as a radiotracer and a double antibody as a separation reagent is described. The radiotracer is prepared by synthesizing 6-(4-O-diethylstilbestryl)-hexanoic acid and coupling its succinimidyl ester with mono-[125I]tyramine in tetrahydrofuran (16 h, 20-22 degrees C). The standard curve is linear (semi-log transformation) and the assay is sensitive (< 0.022 pmol/tube), reproducible (intra- and interassay coefficient of variation values, 5.3 and 8.1%, respectively), and accurate (recovery values, 95-101%), with a non-specific binding less than 3.2%. Diethylstilbestrol concentrations measured in sera of nine patients with prostatic cancer by the proposed assay ranged from 0.170 to 2.517 mumol/l, which corresponded to an only three-fold dosage variation. In all cases tested, dosing was adequate to retain markers of prostatic cancer in serum within accepted limits; nevertheless, individualization of dosing may be necessary to minimize toxicity.
Economou
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Institute of Radioisotopes/Radiodiagnostic Products, NCSR Demokritos, Aghia Paraskevi Attikis, Greece.
Livaniou
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Evangelatos
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GP
Ithakissios
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DS
D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000493:pharmacokinetics* / Q000627:therapeutic use; D004054:Diethylstilbestrol / Q000031:analogs & derivatives* / Q000097:blood* / Q000276:immunology / Q000493:pharmacokinetics / Q000627:therapeutic use; D000431:Ethanol / Q000494:pharmacology; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000097:blood* / Q000188:drug therapy; D011863:Radioimmunoassay
D000970:Antineoplastic Agents; D007074:Immunoglobulin G; D007457:Iodine Radioisotopes; D000431:Ethanol; D004054:Diethylstilbestrol; C004955:fosfestrol