Abstract：
:We describe conditions for determining carboxypeptidase N (EC 3.4.17.3) activity by liquid chromatography. Serum (10 microL) is mixed with the artificial substrates hippuryl-L-arginine (30 mmol/L) and hippuryl-L-lysine (100 mmol/L) in 50 mmol/L 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) buffer solution at pH 8.2 and 7.8, respectively. The hippuric acid product is separated from the substrate in less than 2 min by reversed-phase "high-performance" liquid chromatography and measured spectrophotometrically. o-Methyl hippuric acid is used as internal standard. By this method, optimized for activity and sensitivity of detection, carboxypeptidase N activities are 60-fold greater than those by another procedure (J Chromatogr 266:173-177, 1983). The mean value for 80 normal control subjects was 74.8 (SD 10.3) nmol of hippuric acid released per milliliter of serum per minute for hippuryl-L-arginine substrate, 378 (SD 55) for hippuryl-L-lysine substrate. The sensitivity and precision of the method make it suitable both for routine clinical determinations and as a reference procedure.
journal_name
Clin Chemjournal_title
Clinical chemistryauthors
Hendriks D,Scharpé S,van Sande Msubject
Has Abstractpub_date
1985-12-01 00:00:00pages
1936-9issue
12eissn
0009-9147issn
1530-8561journal_volume
31pub_type
杂志文章abstract：:The human ras gene plays a fundamental role in the transduction of extracellular signals to the nucleus, thereby regulating cell growth and differentiation. Point mutations in the ras gene convert it into a transforming oncogene that has been found in many solid and hematologic malignancies. We describe a rapid and se...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1994-05-01 00:00:00
abstract：BACKGROUND:Although minimum regulatory standards exist for determining QC testing frequency, decisions regarding when and how to run QC samples are not standardized. Most QC testing strategies test control samples at fixed time intervals, often placing the samples in the same position on an instrument during subsequent...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2006.083311
更新日期：2007-04-01 00:00:00
abstract：:We describe a modification of the MacGee method [Anal. Chem. 42, 421 (1970)] for rapid determination of phenytoin (diphenylhydantoin) in plasma by gas-liquid chromatography, in which an ethylaing reagent is used instead of the more common methylating reagents. With this modification, several N-methylated antiepileptic...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1975-05-01 00:00:00
abstract：BACKGROUND:Urinary cross-linked N-telopeptide of type I collagen (NTX) is a reliable bone resorption marker in patients with metabolic bone disease. We assessed a clinically available serum NTX assay suitable for anuric patients on hemodialysis (HD). METHODS:Serum concentrations of NTX, C-terminal telopeptide of type ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2005.051524
更新日期：2005-12-01 00:00:00
abstract：BACKGROUND:Absolute plasma hepcidin concentrations measured by various procedures differ substantially, complicating interpretation of results and rendering reference intervals method dependent. We investigated the degree of equivalence achievable by harmonization and the identification of a commutable secondary refere...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2016.256768
更新日期：2016-07-01 00:00:00
abstract：:A rapid technique (5-10 min) has been developed for fractionating nucleotides from base and nucleoside contaminants in acid extracts of cells, by adsorption to silica gels. Silica gels (1-mL bed volume) were washed with 5 mL of water then with 5 mL of acetonitrile/water (90/10 by vol). After applying 3-mL samples, adj...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1980-09-01 00:00:00
abstract：:Clinically relevant interassay precision profiles for thyrotropin (thyroid-stimulating hormone; TSH) were constructed with human serum pools measured over 4-8 weeks by six immunometric assays, in at least two different reagent lots. Functional sensitivities (the concentration at which the interassay CV is < or = 20%) ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1995-03-01 00:00:00
abstract：:Using a solid-phase monoclonal antibody enzyme immuno-assay, we evaluated in a multicenter study (18 laboratories) the utility of evaluating catalytic activity of human placental alkaline phosphatase (hPLAP, EC 3.1.3.1) in serum as a potential tumor marker. We determined hPLAP in serum samples from 130 patients with o...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1988-10-01 00:00:00
abstract：:A method for determining platinum in biological materials by flameless atomic absorption spectrometry has been developed for use in pharmacological studies of platinum antitumor compounds. Tissue digests are analyzed in a heated graphite atomizer, with use of background correction and ramp temperature charring. We hav...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1977-07-01 00:00:00
abstract：:We evaluated a new commercially available partially purified reduced bovine hemoglobin solution (RBHS) and a new tonometer for use in the quality control of blood gas analyzers. RBHS is manufactured in three different formulations, each corresponding to three different bicarbonate-buffering capacities and concentratio...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1993-05-01 00:00:00
abstract：:We evaluated a new analyzer that measures lactate in undiluted whole blood by direct (or undiluted) amperometry [Nova Stat Profile 7 Analyzer (SP7); Nova Biomedical, Waltham, MA] by comparing it with two other analyzers, one for measuring lactate in whole blood by indirect (or diluted) amperometry [Model 2300; Yellow ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1992-12-01 00:00:00
abstract：:We describe a rapid and simple insulin RIA in which proinsulin and conversion intermediates do not interfere. Three monoclonal antibodies (S1, S2, and S53) were selected for their specificity (directed, respectively, against the B10 region, the junction between A chain and C-peptide, and the junction between B chain a...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1998-07-01 00:00:00
abstract：:The immunoreactivity of anti-triiodothyronine (anti-T3) IgG, pretreated at acidic pH and adsorbed onto polystyrene beads, was significantly greater than that determined for native anti-T3 IgG immobilized at optimum pH 3.5. Acidic-pH-pretreated IgG, adsorbed at pH 7.0 onto ethanol-treated beads, had less immunoreactivi...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1990-03-01 00:00:00
abstract：:To compare six assays of hyaluronan (hyaluronic acid; HYA) in serum, developed in different laboratories, we analyzed 10 samples from each of three groups: healthy persons, patients with primary biliary cirrhosis, and patients with rheumatoid arthritis. All the assays are based on the use of affinity proteins specific...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1992-01-01 00:00:00
abstract：:We evaluated the Reflotron (Boehringer Mannheim) system for measuring activities of alanine aminotransferase (EC 2.6.1.2) and gamma-glutamyltransferase (EC 2.3.2.2). Within- and between-day precision were comparable with conventional analytical methods. The linear range of the methods extended to more than 40-fold the...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1987-06-01 00:00:00
abstract：:The clinical utilities of the emerging biochemical markers for mammary adenocarcinoma CA 15-3, CA 549, CA M26, CA M29, and MCA (mucin-like carcinoma-associated antigen) were assessed by a formal rating according to six desirable marker characteristics. All five indicators similarly have good specificities but limited ...
journal_title：Clinical chemistry
pub_type： 杂志文章,评审
doi：
更新日期：1993-11-01 00:00:00
abstract：:Serum amyloid A (SAA), a sensitive acute-phase protein, is the precursor of AA fibrils in reactive amyloidosis. However, SAA is poorly immunogenic, and development and standardization of immunoassays of this protein have been difficult. We established an automated polyclonal/monoclonal microparticle capture enzyme imm...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1994-07-01 00:00:00
abstract：:We compared results for measurements of creatine kinase isoenzyme MB (CK-MB) by immunoinhibition vs immunoprecipitation, using sera from 53 normal healthy individuals, 55 patients with increased CK-MB associated with acute myocardial infarction, and 42 patients whose blood exhibited one or more abnormal forms of CK by...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1982-10-01 00:00:00
abstract：:We describe a novel ion-selective electrode (ISE) system that can be used in the Abbott Vision analyzer. A reusable sensor pack and a disposable test pack have been miniaturized to approximately the size and weight of a conventional Vision test pack, thus eliminating the need for a separate ISE module. The sensor pack...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1990-12-01 00:00:00
abstract：BACKGROUND:Because cyclosporin A (CsA) and glucocorticoids inhibit the production of interleukin-2 (IL-2) and other cytokines, quantitative analysis of cytokine mRNA might constitute a pharmacodynamic measure for immunosuppressive drug effects. We investigated whether immunosuppressive drugs influence cytokine mRNA exp...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：2002-12-01 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：:We describe a competitive enzyme immunoassay, the ExtrAvidin-biotin system, for determining osteocalcin in human serum or plasma. Antibodies were raised against bovine osteocalcin. Binding of the antibodies to osteocalcin was calcium-dependent. Limit of detection is 0.07 nmol/L (0.4 microgram/L). The standard curve fo...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1992-10-01 00:00:00
abstract：:In this automated apoenzyme reactivation immunoassay system (Ames Optimate) for thyroxin-binding globulin (TBG), the sample and N6-aminohexylflavin adenine dinucleotide-labeled TBG react sequentially with antiserum. Then apoglucose oxidase is added to combine with the free fraction and generate glucose oxidase activit...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1986-05-01 00:00:00
abstract：:Advanced glycosylation end products (AGEs) are thought to play an important role in the development of diabetic complications. Oxidative reactions are essential for the formation of some AGEs, termed glycoxidation products. Increased concentrations of pentosidine, one of such products, are found in tissue and serum in...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1998-02-01 00:00:00
abstract：:We evaluated superoxide dismutase (EC 1.15.1.1) and glutathione peroxidase (EC 1.11.1.9) activities in the erythrocytes of lead-exposed and nonexposed workers from distinct industries localized in the State of São Paulo, Brazil. Concentrations of either lead or protoporphyrin IX, or both, in blood were used to indicat...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1985-10-01 00:00:00
abstract：BACKGROUND:Δ(9)-Tetrahydrocannabinol (THC), 11-nor-9-carboxy-THC (THCCOOH), and cannabinol (CBN) were measured in breath following controlled cannabis smoking to characterize the time course and windows of detection of breath cannabinoids. METHODS:Exhaled breath was collected from chronic (≥4 times per week) and occas...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2013.207407
更新日期：2013-12-01 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：:A number of immunological techniques--radioimmunoassay, enzyme-linked immunosorbent assay (ELISA), electroimmunoassay, radial immunodiffusion, and a variety of immunoprecipitin assays--have been used to quantify apolipoproteins in plasma. This paper outlines their technical details and discusses their major advantages...
journal_title：Clinical chemistry
pub_type： 杂志文章,评审
doi：
更新日期：1990-04-01 00:00:00
abstract：:We compared the performance of an automated assay of creatine kinase MB isoenzyme (CK-MB) mass (Stratus) with that of a CK-MB enzymatic assay routinely used at our institutions. Both of these assays use the same CK-MB-specific monoclonal antibody to immunocapture CK-MB, thus providing a direct means of comparing a mas...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1989-10-01 00:00:00
abstract：:We developed a highly sensitive, convenient assay for measuring blocking-type anti-acetylcholine receptor antibodies, which inhibit the binding of 125I-labeled alpha-bungarotoxin (alpha-BuTx) to the acetylcholine receptor (AChR). This procedure detected inhibitory activities in sera from 76% of patients with myastheni...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1993-10-01 00:00:00
