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Biomedical subjects

A Poklis

Publications and source records attributed to A Poklis.

At least 127 records · Page 7Linked to original sources
PubMedDate not supplied

Evaluation of TDx cocaine metabolite assay.

The TDx cocaine metabolite fluorescence polarization immunoassay (Abbott Laboratories) for the detection of benzoylecgonine (BE) in urine was evaluated. The threshold concentration for BE detection was 0.3 mg/L. The within- and between-run precision of the assay gave coefficients of variation less than 2.3% and 3.5%, respectively. One hundred twenty clinic urines positive for BE by high-pressure liquid chromatography (HPLC) were analyzed by the TDx and EMIT-dau cocaine metabolite assays. All three methods were positive for BE in 116 samples, 96.7%. Two samples were positive by TDx and negative by EMIT-dau, and two samples were positive by EMIT-dau and negative by TDx. Cocaine and ecgonine methyl ester cross reactivity with the TDx assay was less than 2%. One hundred drugs and drug metabolites were added to drug-free urine resulting in no false positive reactions. The same drugs and drug metabolites were also added to urine with 3.0 mg/L BE and analyzed by the TDx. No false positive reactions or inhibition of BE detection occurred.

Cocaine↗
PubMedDate not supplied

Resolution of methamphetamine stereoisomers in urine drug testing: urinary excretion of R(-)-methamphetamine following use of nasal inhalers.

The objective of this study is to determine whether R(-)-methamphetamine inhaled from nasal inhalers produces positive methamphetamine results in currently used urine drug screening procedures and to present a rapid method for distinguishing the optical isomers of methamphetamine. Urine from three subjects inhaling from a Vicks Nasal Inhaler every 20 min for six hours tested positive for methamphetamine by EMIT, Toxilab, TDx, and GC/MS. The chiral derivatizing reagent N-trifluoroacetyl-L-prolyl chloride (L-TPC) was used to form methamphetamine diastereomers allowing rapid identification of each stereoisomer of methamphetamine present in the urine samples. Urine samples positive for amphetamines during routine drug screening were determined to consist of a racemic mixture of methamphetamine. The isomeric composition of methamphetamine present in a urine sample indicates the probable source of the drug.

Administration, Inhalation↗
PubMedDate not supplied

Evaluation of the ETS and ADx urine drug screening immunoassay analyzers.

The Syva ETS and Abbott ADx urine drug testing immunoassay systems were evaluated for analytical performance, ease of operation, data processing, and time of analysis. Urine specimens were analyzed by each system for six drugs of abuse. Discrepancies in drug detection were due to variations in the cut-off concentrations between ADx and EMIT d.a.u. (ETS) reagents. The ETS was found to have several major advantages over the ADx: greater sample load, more convenient "random access," and real time data processing. When analyzing multiple specimens, the turnaround time for the ETS as compared to the ADx was twice as fast for the six-analyte assay. The ADx assay calibrations were stable for two weeks, while the ETS required daily calibration with verification by cut-off calibrators every eight hours. The ETS was found superior to the ADx for multianalyte urine drug screening.

Evaluation Studies as Topic↗
PubMedDate not supplied

Determination of atropine in blood by gas chromatography/mass spectrometry.

A gas chromatographic/mass spectrometric (GC/MS) method for the rapid quantitation of atropine (AT) in blood is presented. A 2.0-mL blood specimen containing deuterated N-methyl-atropine as the internal standard was alkaline-hydrolyzed to convert atropine to tropine. The tropine was extracted by organic solvent which was evaporated to dryness. Tropine in the residue was derivatized with pentafluoropropionic anhydride (PFPA) to the PFPA-tropine ester which was chromatographed on a 25-m cross-linked methyl silicone capillary column with temperature programming at 100 degrees C initially and increased by 20 degrees C/min. The retention time of atropine was 1.7 min. The GC/MS was operated in the SIM mode and the mass fragments monitored were 124 and 287 for AT and 127 and 290 for the internal standard. The assay was linear from 10-300 ng/mL. Replicate analysis of blood specimens containing 200 ng/mL gave a CV = 6.5% (n = 10). Recovery of AT at 75 and 150 ng/mL was 69% (n = 10). The limit of quantitation of AT was 10 ng/mL. Scopolamine may be simultaneously extracted and identified; the retention time was 1.8 min with mass ions 81 and 138.

Atropine↗
PubMedDate not supplied

Estimation of the body burden of arsenic in a child fatally poisoned by arsenite weedkiller.

A three-year-old child died after ingestion of a mouthful of an estimated 44% sodium arsenite solution. Litigation was initiated based on the quality of emergency treatment at a rural hospital. An issue raised in litigation was whether the child could have survived if he had received an additional dose of BAL (dimercaprol). BAL had been sent for from a neighboring city and arrived approximately 2.0 h after admission. The first 50-mg dose of BAL could have combined with a maximum of 30 mg arsenic; a second dose could have brought the total of chelated arsenic to 60 mg. To determine the total body burden of arsenic in the child, multiple tissues were analyzed. The total body burden was estimated at 113 mg, with 100 mg of this total attributable to the ingested solution. The actual body burden after two doses of BAL therefore would have been at least 40 mg, a fatal level.

Arsenic↗
PubMedDate not supplied

Determination of chlorinated hydrocarbon pesticides by solid-phase extraction and capillary GC with electron capture detection.

Pesticides and their metabolites are extracted and concentrated from serum using C18 solid-phase extraction cartridges. The internal standard aldrin is added to 4 mL of serum or plasma, treated with 2 mL of methanol, and the resultant supernatant applied to the C18 cartridge. After several washes, pesticides are eluted from the column with isoctane and the eluate quantified with capillary gas chromatography using electron capture detection. Extraction efficiency is from 70 to 75% and the method detection limit ranges from 0.1-0.7 ng/mL depending on the analyte. Precision studies demonstrate that CVs range from 3.5 to 25.2%. Standard curves are linear to at least 7 ng/mL for lindane and chlordane isomers, heptachlor, heptachlor epoxide, oxychlordane, trans-nonachlor, dieldrin, dichlorodiphenyldichloroethylene (p,p'-DDE), dichlorodiphenyldichloroethane (p,p'-DDD), and dichlorodiphenyltrichloroethylene (p,p'-DDT).

Chromatography, Gas↗
PubMedDate not supplied

Ranitidine interference with the monoclonal EMIT d.a.u. amphetamine/methamphetamine immunoassay.

The interference of ranitidine with the monoclonal EMIT d.a.u. amphetamine/methamphetamine immunoassay (ME) was investigated. Urine specimens collected from 23 patients receiving 150-300 mg of ranitidine daily were found to contain 7-271 mg/L of the drug when analyzed by Remedi automated high pressure liquid chromatography. Only patient specimens and urine samples with ranitidine added at concentrations greater than 91 mg/L gave false positive ME results. Of the 63 patient urine samples analyzed by ME, 12 gave false positive results. All false positive results occurred in the first or second void after ingestion. No false positive results occurred with the polyclonal EMIT d.a.u. amphetamine or TDx amphetamine/methamphetamine II assays.

Amphetamine↗
PubMedDate not supplied

Emit ETS plus ethyl alcohol assay for the determination of ethanol in human serum and urine.

We evaluated the enzymatic Emit ETS Plus Ethyl Alcohol Assay (Emit) intended for the quantitative analysis of ethanol in human urine, serum, and plasma. The assay had been designed for use with the new Syva ETS Plus analyzer. The assay had a linear range up to 6.5 g/L and a low detection limit of 0.1 g/L. Assay within-run precision in serum with ethanol added to 0.25, 0.40, 1.00, 3.00, and 5.00 g/L yielded CVs (n = 32) of 6.1, 5.8, 3.7, 3.5, and 4.5%, respectively. Within-run precision of the assay using with ethanol added to 0.25, 0.40, 1.00, 3.00, and 5.00 g/L yielded CVs (n = 32) of 4.9, 5.0, 4.3, 3.3, and 5.0%, respectively. Between-run precision of aqueous controls yielded 0.41 +/- 0.02 g/L ethanol (target value, 0.40 g/L), CV = 4.5% (n = 31) and 3.05 +/- 0.06 g/L ethanol (target value, 3.00 g/L) CV = 2.1% (n = 31). Absolute recovery of the assay with 0.40 to 6.00 g/L ethanol added to serum and urine yielded mean recovery values of 105.5 and 101.5%, respectively. Results of the analysis of patient serum and urine specimens for ethanol by the Emit assay correlated well with those obtained by other methods. The Emit assay was found to be rapid, precise, and accurate for the determination of ethanol in clinical specimens. It was also found to be free of interferences from small molecular weight alcohols, aldehydes, ketones, and glycols. The Emit assay's linear range of up to 6.50 g/L ethanol was a major advantage over the ADx and aca assays; these assays were only linear to 3.00 g/L.

Chromatography, Gas↗
PubMedDate not supplied

Evaluation of the Syva ETS Plus urine drug and serum ethanol analyzer.

The Syva ETS is an automated system designed for analysis of drugs of abuse in urine. Recently, the Syva Company has upgraded this system to the ETS Plus, which is capable of analyzing ethanol in urine, serum, or plasma. We evaluated the new ETS Plus for urine screening of barbiturates, benzodiazepines, cocaine metabolite, opiates, and phencyclidine. Results of 505 patient sample assays obtained by ETS Plus were compared with those of ETS. There were only four discrepant results which had absorbance rates close to the low calibrator cutoff values. The within-run precision of the ETS Plus Ethyl Alcohol Assay yielded a CV of 2.6% at a target value of 1.00 g/L (1.06 +/- 0.03 g/L, n = 32) and a CV of 3.2% at a target value of 0.40 g/L (0.42 +/- 0.01 g/L, n = 30). The linear regression analysis of 30 patient serum ethanol results by the ETS Plus and by gas chromatography yielded y = 0.939 x + 0.03 g/L. The software modifications in the new ETS Plus allow the accurate quantitation of ethanol in serum and reliable detection of drugs of abuse within the same batch.

Autoanalysis↗
PubMedDate not supplied

Direct determination of benzoylecgonine in serum by EMIT d.a.u. cocaine metabolite immunoassay.

An EMIT d.a.u. immunoassay for urine testing was applied on the Syva ETS Plus analyzer for the detection of the cocaine metabolite, benzoylecgonine (BE), in human serum. Serum was analyzed without prior extraction, concentration, or matrix modification. Calibrators and serum controls were prepared from EMIT d.a.u. calibrators that were reconstituted and diluted with EMIT Tox serum calibrator. The assay cutoff concentration for BE was 50 ng/mL. The within-run and between-run precisions of the assay were both less than 5%. Analysis of 162 patient serums yielded 43 BE positive results. All EMIT positive serum BE results were confirmed by gas chromatography-mass spectrometry. All patients with positive BE serums also had BE positive urine samples. Serum bilirubin and triglycerides as high as 38 mg/dL and 319 mg/dL, respectively, did not interfere with the assay. Modification of the EMIT urine assay allowed for a simple, rapid, and reliable method for the detection of BE in serum.

Cocaine↗
PubMedDate not supplied

alpha-Benzyl-N-methylphenethylamine (BNMPA), an impurity of illicit methamphetamine synthesis: I. Physical characterization and GC-MS analysis of BNMPA and anticipated metabolites in urine.

alpha-Benzyl-N-methylphenethylamine (BNMPA) is an impurity of illicit methamphetamine synthesis. We synthesized BNMPA and three of its anticipated metabolites: N-demethyl-alpha-benzyl-phenethylamine, 1,3-diphenyl-2-propanone, and 1,3-diphenyl-2-propanol. The purity and structure of these compounds and their heptafluorobutyric anhydride (HFBA) derivatives were confirmed by melting point, gas chromatography-mass spectrometry (GC-MS), and nuclear magnetic resonance. A GC-MS method to detect these compounds in urine, using liquid-liquid extraction and derivatization with HFBA, was developed. Interference studies showed BNMPA and its proposed metabolites to be well-resolved from other common phenethylamine drugs and Health and Human Services-Forensic Urine Drug Testing required analytes. The limit of detection of BNMPA and its metabolites was 2.5 ng/mL; the limit of quantitation (LOQ) of the four compounds was 25 ng/mL. The calibration curves were generally linear from 25 to 500 ng/mL. Typical within-run coefficients of variation (CVs) at the LOQ ranged from 13 to 20% (n = 8). Between-run CVs over 1 month at 25 ng/mL were from 9 to 28%, and at 500 ng/mL, they were from 2.6 to 3.9%. The detection of BNMPA or its metabolites in urine samples may provide a marker of use of illicitly synthesized methamphetamine.

Aluminum↗
PubMedDate not supplied

alpha-Benzyl-N-methylphenethylamine (BNMPA), an impurity of illicit methamphetamine synthesis: II. Metabolism and urinary excretion (human).

Methamphetamine is a popular drug of abuse, which is readily synthesized in clandestine laboratories. Illicit synthesis results in the formation of various contaminants. Few impurities have been studied in vivo, and their metabolic fate is unknown. One such impurity is alpha-benzyl-N-methylphenethylamine (BNMPA). The detection of BNMPA or its metabolites in urine samples may provide a marker of use of illicitly synthesized methamphetamine. Benzphetamine is structurally similar to BNMPA. Based on metabolic studies of benzphetamine, we predicted the four major metabolites of BNMPA to be the N-demethyl compound, diphenyl-2-propanone (DP2P), p-hydroxy-N-demethyl BNMPA, and p-hydroxy-BNMPA. One male volunteer ingested 5 mg BNMPA. Seventeen urine specimens were collected over 50 h post ingestion. These specimens were analyzed for BNMPA and its four predicted major metabolites by gas chromatography-mass spectrometry following beta-glucuronidase hydrolysis or acid hydrolysis, liquid-liquid extraction, and derivatization with heptafluorobutyric anhydride. Specimens were also analyzed without hydrolysis to determine the abundance of nonconjugated ("free") metabolites. Only trace amounts of BNMPA and its N-demethyl metabolites were detected, and maximum excretion was from 2 to 4 h post ingestion. In the nonhydrolyzed samples, the phenyl-OH metabolites were also present in only trace amounts. Maximum excretion of DP2P was at 2 h. Following either hydrolysis procedure, phenyl-OH-BNMPA and phenyl-OH-N-demethyl BNMPA were the major metabolites detected. Maximum excretion of these two metabolites occurred at 4 h. With the exception of the parent compound and the N-demethyl metabolite, excretion of metabolites was greater than the limit of detection of this procedure (2.5 ng/mL) up to 21 h post ingestion. Metabolites were detectable in sufficient quantities to serve as an adequate marker of illicit methamphetamine consumption within the preceding 24 h.

Benzphetamine↗
PubMedDate not supplied

alpha-benzyl-N-methylphenethylamine (BNMPA), an impurity of illicit methamphetamine synthesis: III. Detection of BNMPA and metabolites in urine of methamphetamine users.

Eighty urine specimens collected from drug rehabilitation programs, which had been screened by immunoassay and confirmed positive by gas chromatography-mass spectrometry (GC-MS) for methamphetamine, were further analyzed for alpha-benzyl-N-methylphenethylamine (BNMPA) and its urinary metabolites, N-demethyl-BNMPA, diphenyl-2-propanone (DP2P), diphenyl-2-propanol, p-OH-N-demethyl-BNMPA, and p-OH-BNMPA. BNMPA is an impurity of illicit methamphetamine synthesis. Analysis of BNMPA and its metabolites was performed by quantitative GC-MS following beta-glucuronidase hydrolysis, liquid-liquid extraction, and derivatization with heptafluorobutyric anhydride. Two urine specimens contained detectable amounts of BNMPA and/or its metabolites. One contained trace amounts (greater than the limit of detection but less than the limit of quantitation) of N-demethyl-BNMPA and DP2P, as well as 0.04 mg/L p-OH-N-demethyl-BNMPA. The other contained trace amounts of BNMPA, p-OH-BNMPA, and p-OH-N-demethyl-BNMPA, as well as 0.03 mg/L N-demethyl-BNMPA. Prior to analyzing these urine specimens, pure reference material of p-OH-BNMPA was made available, and analysis confirmed our previous tentative identification of p-OH-BNMPA as a major metabolite of BNMPA. Detection of BNMPA or its metabolites in biological samples may serve as a marker of illicit methamphetamine administration.

Amphetamine↗
PubMedDate not supplied

A simple, rapid gas-liquid chromatographic procedure for the determination of valproic acid in serum.

A simple, rapid method for the gas-liquid chromatographic (GLC) determination of valproic acid in serum without prior derivatization on a Nukol wide-bore capillary column is presented. The method was determined to have a lower limit of detection (LOD) of 5 mg/L and a lower limit of quantitation (LOQ) of 10 mg/L; the method was linear up to 6000 mg/L. Within-run precision (expressed as percent coefficient of variation [CV]) for control specimens containing 60 mg/L and 120 mg/L was 4.3% CV (n = 10) and 3.0% CV (n = 10), respectively. The between-run precision of control sera analyzed over four week yielded 8% at 25 mg/L, 5% at 60 mg/L, and 3% at 120 mg/L. The absolute, uncorrected, analytical recoveries of valproic acid at 10, 32, and 120 mg/L were 97% (n = 5), 101% (n = 5), and 84% (n = 5), respectively. The absolute recovery of the internal standard was 97% (n = 9). Drugs commonly indicated for therapeutic monitoring and other serum constituents were found not to interfere with the procedure. The results of an intermethod comparison study of serum specimens analyzed by TDx immunoassay versus the presented GLC method demonstrated good correlation. At 95% confidence limits, no statistically significant differences were observed between results (p < 0.05). The method is particularly advantageous to toxicology laboratories because chromatography is performed on a polar GLC column that can be modified readily for the routine clinical analysis of other polar compounds such as ethylene glycol and other glycols.

Anticoagulants↗
PubMedDate not supplied

A suicide by pancuronium bromide injection: evaluation of the fluorometric determination of pancuronium in postmortem blood, serum and urine.

A fatal case of suicidal injection of pancuronium bromide is presented. Pancuronium was detected in blood and urine by ion-pair extraction and fluorometry. An evaluation of the fluorometric procedure for the determination of pancuronium in postmortem blood, serum and urine is presented. Stability of the extracted ion-pair, possible interferences from other drugs, and the effects of specimen storage were studied.

Adult↗