Abstract：
:Plasma concentrations of delta-9-tetrahydrocannabinol, the principal psychoactive cannabinoid in marijuana, decline to values substantially less than 1 microgram/L within a few hours after a subject has smoked a marijuana cigarette. Using a single-quadrupole gas chromatograph-mass spectrometer (GC/MS) operated in the negative chemical-ionization mode and retrofitted with a High Energy Dynode detector system, we measured delta-9-tetrahydrocannabinol and a primary metabolite, 11-nor-delta-9-tetrahydrocannabinol-9-COOH. Using a trifluoroacetic anhydride derivatization procedure and the High Energy Dynode detector system, we improved by 6.25-fold the limit of detection for delta-9-tetrahydrocannabinol in plasma over that obtained with the same GC/MS system without the new detector (80 vs 500 ng/L). The new detector system will thus permit further investigation of the post-distribution pharmacokinetics of delta-9-tetrahydrocannabinol and detection of delta-9-tetrahydrocannabinol in plasma for a longer time after ingestion of the drug in forensic cases. The High Energy Dynode detector system should be applicable to a wide variety of other GC/MS analyses that require significantly improved sensitivity.
journal_name
Clin Chemjournal_title
Clinical chemistryauthors
Shaw LM,Edling-Owens J,Mattes Rsubject
Has Abstractpub_date
1991-12-01 00:00:00pages
2062-8issue
12eissn
0009-9147issn
1530-8561journal_volume
37pub_type
杂志文章abstract：:A gas-chromatographic method for urinary organic acid analysis is described, designed to be used routinely for the diagnosis of organic aciduria. It involves extraction of urine with ethyl acetate, dehydration of extract residues, and trimethylsilylation. Organic acids are identified by using an extensive list of rete...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1980-12-01 00:00:00
abstract：:We compared the analytical performance of the Kodak Ektachem XR700 assays of iron (Fe) and total iron-binding capacity (TIBC) with that of a conventional ferrozine assay (performed with a Cobas-Bio) and occasionally with that of atomic-absorption spectrometry (AAS). The correlation was modest between Kodak and Cobas-B...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1990-10-01 00:00:00
abstract：:I describe an assay for serum estriol during pregnancy, which does not require prior extraction or chromatography of the serum. Fifty microliters of 20-fold diluted serum can be assayed to detect as little as 20 pg of estriol. For a 20 mug/liter serum estriol concentration the CV was 16%; for 100 mug/liter concentrati...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1976-04-01 00:00:00
abstract：:The commonly used methods of assessing the precision of the automated leukocyte differential have certain drawbacks that affect the validity and comparability of results. In the present report, we introduce a procedure based on building precision profiles from a large number of within-run imprecision experiments. The ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1996-07-01 00:00:00
abstract：:Diagnosing cobalamin deficiency is often difficult. We investigated the diagnostic strategies that 224 general practitioners used to assess cobalamin status and the criteria on which they based their decisions to supplement patients. From all serum cobalamin analyses carried out at a single laboratory during 1993, ind...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1999-02-01 00:00:00
abstract：:We assessed the LKB "Delfia" (time-resolved dissociation-enhanced lanthanide fluoroimmunoassay) and the Amersham "Amerlite" (enhanced luminescent immunometry) assays of thyrotropin in serum. Both assays are sensitive (respective detection limits: 0.02 and 0.04 milli-int. unit/L) and have very good within- and between-...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1987-08-01 00:00:00
abstract：BACKGROUND:Plasma concentrations of small dense (sd)-LDL are associated with the prevalence of cardiovascular events. However, the special equipment and long assay times required for sd-LDL measurement have hindered its clinical application. Herein, we report development of a simple homogeneous assay for sd-LDL-cholest...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2010.149559
更新日期：2011-01-01 00:00:00
abstract：:We compare measurement of total fast hemoglobin (HbA1) by "high-performance" liquid chromatography and by electrophoresis on agar gel. Blood samples were obtained from a diverse population (n = 222): offspring of two diabetic parents, diabetic patients with and without retinopathy, diabetic and non-diabetic pregnant w...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1981-03-01 00:00:00
abstract：:Direct-injection analysis for phenylalanine in plasma by isocratic "high-performance" liquid chromatography (HPLC) is described. For chromatographic separation I use an internal-surface reversed-phase silica support. The method involves ultraviolet detection, requires as little as 10 microL of plasma (routinely 20 mic...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1989-06-01 00:00:00
abstract：:We have developed a series of photochemical silver stains that are more than 100 times as sensitive as the Coomassie Blue stains. These stains facilitate the quantitative estimation of proteins in two-dimensional gel patterns. Recently, we discovered that by using light (photodevelopment) to catalyze the reduction of ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1984-12-01 00:00:00
abstract：:We describe here a nonisotopic immunoassay, based on particle-counting technology, for the determination of urinary albumin. The assay takes only 35 min and has been fully automated on the IMPACT (Acade Diagnostic Systems, Brussels, Belgium) machine. The system measures albumin within a linear range between 6.25 and 5...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1988-02-01 00:00:00
abstract：:Gene mutations responsible for the majority of Duchenne/Becker muscular dystrophy (DMD/BMD) and cystic fibrosis (CF) chromosomes have been identified. We describe a DNA-based strategy, rather than the traditional biochemical assays, for screening newborns. DNA sequences spanning the CF mutation and several DMD/BMD del...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1990-10-01 00:00:00
abstract：:The values of apolipoproteins (apo) A-I and B were determined in a population sample of hospital outpatients with a standardized method to verify if the cutpoints calculated in a cross-sectional study in the US are usable with other populations. We also tested the apolipoproteins' ability to discriminate between healt...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1998-01-01 00:00:00
abstract：PURPOSE:To review information on the use of laboratory tests in screening, diagnosis, and monitoring of acute and chronic hepatic injury. DATA SOURCES AND STUDY SELECTION:A MEDLINE search was performed for key words related to hepatic diseases, including acute hepatitis, chronic hepatitis, alcoholic hepatitis, cirrhos...
journal_title：Clinical chemistry
pub_type： 杂志文章,评审
doi：
更新日期：2000-12-01 00:00:00
abstract：:C-reactive protein (CRP) concentrations were serially determined in serum after kidney or heart transplantation. The initial postsurgical CRP response in these patients was compared with that of control patients undergoing related procedures but not subjected to immunosuppressive therapy. Immunosuppression clearly dep...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1986-04-01 00:00:00
abstract：:We evaluated and compared five commercial radioimmunoassay kits with a standard counter-immunoelectrophoretic assay for the measurement of prostatic acid phosphatase in serum. Four of the five radioimmunoassays performed as described by the supplier with respect to sensitivity, stability, precision, linearity, analyti...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1981-10-01 00:00:00
abstract：:The technology needed to genetically engineer antibodies is evolving rapidly and the potential utility of these novel reagents is being explored with vigor. The process includes cloning of the antibody genes, their in vitro manipulation and mutagenesis, expression in a suitable host/vector system, and, for commercial ...
journal_title：Clinical chemistry
pub_type： 杂志文章,评审
doi：
更新日期：1989-09-01 00:00:00
abstract：:Measurement of serum ascorbate may be useful in long-term population studies because of the possible influence of ascorbate on numerous physiological factors. We describe an automated method for determining ascorbate in serum and urine by using the reduction of ferric iron by ascorbate and the formation of a color bet...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1975-09-01 00:00:00
abstract：:The optimal measurement method and clinical application of the therapeutic drug monitoring of cyclosporine remain uncertain. At a workshop held at Hawk's Cay, FL, from January 14 to January 17, 1990, 57 scientists presented their latest research findings, either in formal papers or as discussants. Lively debate and di...
journal_title：Clinical chemistry
pub_type： 共识发展会议,杂志文章,评审
doi：
更新日期：1990-08-01 00:00:00
abstract：:We describe an automated enzymatic procedure for quantifying creatine in erythrocytes. In this assay, after sample clean-up, creatine kinase (CK; EC 2.7.3.2) and pyruvate kinase (EC 2.1.7.40) are used as auxiliary enzymes; lactate dehydrogenase (EC 1.1.1.27) is used in the indicator reaction. CK is also used as the st...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1996-02-01 00:00:00
abstract：BACKGROUND:Rapid detection of biological threat agents is critical for timely therapeutic administration. Fluorogenic PCR provides a rapid, sensitive, and specific tool for molecular identification of these agents. We compared the performance of assays for 7 biological threat agents on the Idaho Technology, Inc. R.A.P....
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2005.052522
更新日期：2006-01-01 00:00:00
abstract：:In this immunoenzymatic assay for human lutropin (hLH) we used bi-specific antibodies (BiAbs) obtained from the fusion of two hybridomas producing antibodies to beta-D-galactosidase and hLh. The BiAb complexed with the enzyme beta-D-galactosidase was used as tracer in a double-determinant assay. We compared the assay ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1990-01-01 00:00:00
abstract：:We describe a simple and convenient method for processing small amounts of tissue samples for trace-metal measurements by atomic absorption spectrometry, by use of a modified Parr microwave digestion bomb. Digestion proceeds rapidly (less than or equal to 90 s) in a sealed Teflon-lined vessel that eliminates contamina...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1989-03-01 00:00:00
abstract：BACKGROUND:Plant-derived cardenolides reportedly possess anticancer properties in human leukemic cells via selective induction of apoptosis, cell cycle arrest, and differentiation. Selective induction of apoptosis with mammalian-derived digoxin-like immunoreactive factor (DLIF) could provide new strategies for anticanc...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2006.082081
更新日期：2007-07-01 00:00:00
abstract：:A one-stage semiautomated method for estimating total phospholipids in plasma is reported. The phospholipids are extracted into aqueous ethanol, combined with a Lewis acid, and the change in pH is monitored colorimetrically. The method, compared with the acid digestion method of Gomori [J. Lab. Clin. Med. 27, 955 (194...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1977-09-01 00:00:00
abstract：:We have developed a liquid chromatography-isotope dilution mass spectrometry procedure to quantify total cholesterol in serum. A particle-beam interface was used for coupling the liquid chromatograph and the mass spectrometer. After electron impact ionization the ions m/z = 386 and m/z = 389 were used for selective io...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1997-10-01 00:00:00
abstract：:We describe a simple fluoroimmunoassay for the determination of thyroxine concentrations in serum. The method, "sequential addition, separation fluoroimmunoassay," involves both thyroxine labeled with fluorescein and magnetizable cellulose/iron oxide particles to which antibodies to thyroxine have been covalently link...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1980-11-01 00:00:00
abstract：:We describe the measurement of rheumatoid factor in human sera with a rate nephelometer. The National Reference Preparation for Rheumatoid Factors is used to calibrate the assay in International Units. We used Hyland Positive Control, Level I, as a secondary standard. The standard curve is exponential, but is linear w...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1979-11-01 00:00:00
abstract：:We describe the sensitive and precise determination 5-hydroxytryptophan in plasma from patients treated with this compound. The method is based on solvent extraction of plasma, high-performance liquid chromatography and continuous fluorometric detection after reaction with phthaldialdehyde in strong acid. The combined...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1978-02-01 00:00:00
abstract：:We describe an improved separation of the isoenzymes of aspartate aminotransferase (EC 2.6.1.1), based on ion-exchange chromatography. Involving the "Fast Protein Liquid Chromatography" system (Pharmacia) with a MonoQ column, this rapid, reproducible method for quantifying the mitochondrial enzyme shows good resolutio...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1990-02-01 00:00:00
