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.

Preparation of the N-(4'-hydroxy-[3'-125I]iodophenethyl)-6-(4-O-diethylstilbestryl)hexanam ide for diethylstilbestrol radioimmunoassays.

The synthesis of a radioiodinated diethylstilbestrol (DES) derivative is described. This derivative was prepared by coupling the previously synthesized active ester of 6-(4-O-diethylstilbestryl)hexanoic acid with mono-[125I]iodotyramine in dry tetrahydrofuran (20 to 22 C, 16 hours). The mono-[125I]iodotyramine was prepared using a chloramine-T method and purified by paper electrophoresis. The final product, N-(4'-hydroxy-[3'-125I]iodophenethyl)-6-(4-O- diethylstilbestryl)hexanamide, was separated by thin-layer chromatography (cyclohexane/ethanol/NH4OH 2.5 N/acetone; 40:50:5:20, v/v/v/v); it was stable for 2 months in ethanol at 4 C and had a specific activity higher than 540 Ci/mmol. The [125I]DES amide synthesized was found to retain the immunoreactivity of DES, since it competed with [3H]DES or DES in an in vitro radioimmunoassay system for the binding sites of a rabbit anti-DES antibody; thus, it seems to be capable of replacing the tritiated tracer used so far in DES radioimmunoassays.

Direct radioimmunoassay for diethylstilbestrol in serum.

A radioimmunoassay method for the measurement of diethylstilbestrol directly on 50 microliters of human serum was established using a tritium-labeled radioligand and a double antibody as a separation reagent. The assay was sensitive (less than 0.17 micrograms/L), reproducible (intra-assay and interassay coefficient of variation values, 8.14% and 8.25%, respectively), and accurate (recovery up to 95%). Factors influencing the assay are identified and discussed.

Effect of angiotensin-converting enzyme inhibitor on collagenolytic enzyme activity in patients with acute myocardial infarction.

Matrix metalloproteinases and their tissue inhibitors are key enzymes degrading myocardial collagen in acute myocardial infarction (AMI). The aim of the present study was to determine whether angiotensin-converting enzyme inhibitors (ACEI) influence collagenase-1 (MMP-1) and their tissue inhibitor (TIMP-1) activity in AMI patients. Plasma levels of MMP-1, TIMP-1 and MMP-1/TIMP-1 complex were measured in 24 patients (aged 58.4 +/- 13.9 years) with AMI. Thirteen patients received perindopril 4 mg/day (group A) and 11 did not (group B). Plasma samples collected on admission and at 0, 3, 6, 9, 12, 18, 24, 36 and 48 hours and on days 3, 4, 5, 7, 15 and 30 thereafter were analyzed by relevant ELISA kits. Ejection fraction (EF) was assessed by ventriculography and end-diastolic diameter (EDD) echo-study on days 6 and 30. Values of collagenolytic enzymes of group A compared with those in group B were on average lower by 34%, 18.3% and 40%, respectively. The difference in values between groups at 0 h, 3 h and 9 h was significant (p < 0.048). ANOVA repeated measurement analysis showed significance within subjects for MMP-1 alone (p < 0.043) and for MMP-1 and ACEI (p < 0.046), while for TIMP-1 and MMP-1/TIMP-1 complex significance was only p < 0.0009. Regarding EDD changes, patients in group A showed minimal or no changes (51.23 +/- 1.8 mm to 51.6 +/- 2.13 mm), their EF was 38.8% and infarct size was medium to large. In contrast, group B showed a trend to increase EDD (41 +/- 0.78 mm to 42.33 +/- 0.59 mm), their EF was 50.5% and infarct size was small to medium. In conclusion, early initiation of ACEI treatment reduces collagenolytic activity. This effect may be considered an alternative mechanism for beneficial effects on postinfarction remodeling.

Circulating levels of atherogenesis-associated adipocytokines and apoptotic markers are differentially influenced by hormone therapy, tibolone and raloxifene in healthy postmenopausal women.

OBJECTIVE: Estrogen agonist compounds may exert cardioprotective activity by modulating adipocytokine concentration and apoptosis. The objective of this study was to evaluate the effects of hormone therapy, tibolone and raloxifene on the serum adipocytokines resistin and adiponectin as well as on circulating markers of receptor-mediated apoptosis. Design Randomized, open-label, intervention study in the Menopause Clinic of a University Hospital. METHODS: One hundred healthy postmenopausal women were randomized to the following groups: conjugated equine estrogens 0.625 mg (CEE) (n = 16); 17 beta-estradiol 1 mg plus norethisterone acetate 0.5 mg (E(2)/NETA) (n = 15); tibolone 2.5 mg (n = 18); raloxifene HCl 60 mg (n = 20); and no treatment (n = 19). Eighty-eight women completed the 3-month study period. Main outcome measures were levels of serum adiponectin, resistin, soluble Fas and Fas ligand. RESULTS: Levels of serum adiponectin decreased significantly in the tibolone group (baseline: 10 556.7 +/- 4213.5 ng/ml; 3 months: 7856.3 +/- 3450.7 ng/ml; p = 0.0001) and increased in the CEE group (baseline: 9268.1 +/- 5158 ng/ml; 3 months: 11 302.6 +/- 4980.9 ng/ml; p = 0.01). Serum resistin values increased only in the tibolone group (baseline: 2.81 +/- 0.89 ng/ml; 3 months: 3.55 +/- 1.31 ng/ml; p = 0.04), while the level of Fas ligand decreased significantly in the E2/NETA (baseline: 70.4 +/- 21.9 pg/ml; 3 months: 62.1 +/- 18.6 pg/ml; p = 0.02) and tibolone group (baseline: 68.2 +/- 25.7 pg/ml; 3 months: 59.2 +/- 21.7 pg/ml; p = 0.01). CONCLUSIONS: Of the regimens investigated, only unopposed estrogens may exert an atheroprotective effect through the increase of adiponectin and a resultant favorable lipid and anti-inflammatory profile.