Inhibition of the nuclear localization of [3H]estradiol in rat uterine tissue in vitro.

The temperature coefficient (Q10) for the nuclear-cytoplasmic intracellular distribution of specifically-bound [3H]estradiol is approximately 1.0 over the interval 10-30 degrees C. However, this value increases to 3.19 for the temperature influence upon the nuclear-cytoplasmic localization of hormone between 30 degrees and 37 degrees C. A Q10 value of this magnitude is indicative of a biological, rather than physical, translocation event. In assessment of a biological basis for translocation, several antimicrotubular/antimicrofilamentous agents were used alone and in combination to ascertain their effects upon in vitro nuclear localization of labeled estradiol in the uterus. The incubation of uterine tissue in D2O-Locke-Ringer's solution containing 10(-4) M colchicine or vinblastine significantly reduced the nuclear localization of [3H]estradiol to nonspecific retention. Tissue uptake of the hormone, cytoplasmic binding and retention of estrogen, and the nucleophilic property of the receptor-estrogen complex (REC) were unaffected. Other drug treatments were without effect upon nuclear occupancy of the REC. The apparent inhibition of translocation by the above regimen could be due to an alteration in cellular architecture incompatible with hormone movement or the result of a direct effect upon cellular components which impede the dynamic interactions of REC in nuclei of whole tissue. Although these results do not necessarily imply that a functional cytoskeleton is required for translocation, we suggest that the estrogen-mediated nuclear occupancy of REC is a biological process susceptible to disruption.

Determination of LSD in urine by capillary column gas chromatography and electron impact mass spectrometry.

A procedure for the determination of LSD (lysergic acid diethylamide) in urine at concentrations as low as 0.5 ng/ml is presented. After addition of deuterium-labeled LSD as the internal standard, a rapid n-butyl chloride extraction of LSD from urine at pH 8 is followed by formation of the trimethylsilyl (TMS) derivative by treatment with N,O-bis(trimethylsilyl)trifluoroacetamide. The TMS derivative of LSD is identified and quantified by selected ion monitoring with a fused-silica capillary column and electron impact ionization. The procedure was used to monitor LSD concentrations in urine for eight hours following oral administration of 70.5 micrograms of LSD to two human volunteers. Concentrations of LSD determined by the assay are compared with concentrations determined by two other methods of analysis, a radioimmunoassay and a high-performance liquid chromatographic (HPLC) assay. Data concerning the stability of LSD in urine are also presented.

The effect of activated charcoal on N-acetylcysteine absorption in normal subjects.

The discovery of the effectiveness of oral antidotes such as N-acetylcysteine (NAC) for acetaminophen poisonings has raised questions about the appropriateness of concomitant administration with activated charcoal. A number of studies have attempted to clarify this question without complete success. This study was designed to evaluate the difference in serum levels of NAC when given with activated charcoal. Nineteen patients completed a two-phase cross-over study in which they served as their own controls. Each subject in phase 1 received 140 mg/kg of diluted, chilled NAC orally, and venous blood samples were drawn for analysis. Phase 2 consisted of a 100-g dose of activated charcoal followed by NAC. Samples were transported immediately and assayed using spectrophotometry. A reduction in peak NAC level of 29% (P less than .02) and a reduction of total area under the curve (AUC) of 39% (P less than .001) was noted. Although it may be preferable to avoid completely the use of activated charcoal when using NAC to treat overdoses of acetaminophen, we recommend that if these agents are used together, doses of NAC be increased by 40% to compensate for the decreased oral absorption of NAC.

An evaluation of the TDX fluorescence polarization immunoassays for procainamide and n-acetylprocainamide.

The TDX fluorescence polarization assays (FPIA) for procainamide (PA) and n-acetylprocainamide (NAPA) were evaluated. Coefficients of variation for within- and between-assay precision studies were less than 6%. Both methods correlated well with a referenced HPLC technique; r2 values for PA and NAPA were 0.980 and 0.986, respectively.

Analysis of ethchlorvynol (Placidyl): evaluation of a comparison performed in a clinical laboratory.

Common techniques for analyzing ethchlorvynol (Placidyl) by colorimetry and gas liquid chromatography are evaluated. Matrix effects are thoroughly examined to determine their contribution to the validity of results.

Comparison of quinidine by fluorescence polarization immunoassay and high pressure liquid chromatography.

Analysis of quinidine was performed using fluorescence polarization immunoassay (Abbott TDXTM) with an ion-pairing adsorption high pressure liquid chromatography (HPLC) technique as the comparative method. Correlation of 110 clinical samples was excellent (r2 = 0.983). TDX calibration appeared stable for 14 days. There is minimal contribution to the concentration of quinidine due to the presence of metabolite. The TDX method is rapid, precise, and accurate.

An evaluation of the EMIT st assay for the detection of tricyclic antidepressant drugs in plasma or serum.

The EMIT st assay for tricyclic antidepressant drugs (TADs) was evaluated for use as a screening technique in the detection of these drugs in serum or plasma. The qualitative assay was found to be rapid, easy to perform, requires no sample or reagent preparations, and reliably detected the TADs in patient samples at concentrations greater than or equal to 200 ng/mL. The technique also detected seventeen of nineteen patient samples with TAD concentrations ranging from 150-199 ng/mL and ten of forty-three samples with concentrations less than 150 ng/mL. The EMIT st assay was found to be a reliable technique for detecting high concentrations of TADs and is well-suited for use in emergency drug screening situations.

Spurious phenobarbital levels by fluorescence polarization immunoassay using TDx analyzer in patients with renal disease.

Results of phenobarbital analyses are presented for 14 patients with chronic renal failure, and compared using gas-liquid chromatography (GLC), enzyme immunoassay (EIA), and fluorescence polarization immunoassay (FPIA). Correlation of FPIA with GLC and EIA was poor.

An evaluation of common methods for acetaminophen quantitation for small hospitals.

Rapid, reliable serum acetaminophen quantitations assist in the diagnosis of the toxic patient and direct the clinician in the course of aggressive treatment. Reliable performance must be tempered with economic consideration, especially for small laboratories with infrequent testing. Two commonly available colorimetric techniques for acetaminophen (nitration and ferric reduction) are evaluated using both commercial and laboratory reagents. Enzyme immunoassay (EMIT) is also performed. Results are compared to an HPLC reference method.

An HPLC method for the simultaneous quantitation of quinidine, procainamide, N-acetylprocainamide, and disopyramide.

A high performance liquid chromatographic method is reported, which incorporates three internal standards (I-cinchonidine, N-propylprocainamide, and para-chlorodisopyramide) for the simultaneous quantitation of four commonly prescribed antiarrhythmic drugs: quinidine, procainamide, N-acetylprocainamide, and disopyramide. Compounds were separated using combined ion-pairing and adsorption chromatography on a silica column. Inter-run variation was 5.9 CV% for all drugs.

A single-step assay for lidocaine and its major metabolite, monoethylglycinexylidide, in plasma by gas-liquid chromatography and nitrogen phosphorus detection.

A single-step extraction method for the analysis of lidocaine and its primary metabolite, monoethylglycinexylidide (MEGX), is described. Alkalinized plasma or serum is extracted with ethyl acetate. Trimecaine is used as the internal standard. One microliter of the ethyl acetate extraction solvent is injected directly onto a Carbowax-KOH column fitted to a gas chromatograph equipped with a nitrogen-phosphorus detector. This procedure provides a rapid and reliable analysis for lidocaine and MEGX, requires only a single glass tube, and eliminates back-extractions and solvent evaporation.