Abstract：
BACKGROUND:The "unit" for "enzymic activity" (U = 1 micromol/min) was recommended by the International Union of Biochemistry and Molecular Biology (IUB) in 1961 and is widely used in medical laboratory reports. The general trend in metrology, however, is toward global standardization through defining units coherent with the International System of Units (SI). APPROACH:Several proposals were advanced from the IFCC, International Union of Pure and Applied Chemistry, and IUB regarding the definition for enzymic activity as well as the terms for kind-of-quantity, units, symbol, and dimension. In 1977, international agreement was reached between these bodies and WHO that "catalytic activity" (z), of a catalyst in a given system is defined by the rate of conversion in a measuring system (in mol/s) and expressed in "katal" (symbol, kat; equal to 1 mol/s). The katal is invariant of the measurement procedure, but the numerical quantity value is not. Gaining support for the katal from the final arbiter, the General Conference on Weights and Measures, was slow, but Resolution 12 of 1999 adopted the katal (symbol, kat) as a special name and symbol for the SI-derived unit, mol/s, used in measuring catalytic activity. CONCLUSIONS:Laboratory results for amounts of catalysts, including enzymes, measured by their catalytic activity can now officially be expressed in katals and are traceable to the SI provided that the specified indicator reaction reflects first-order kinetics. The conversion from "unit" is: 1 U = 16.667 x 10(-9) kat. Further derived quantities have coherent units such as kat/L, kat/kg, and kat/kat = 1.
journal_name
Clin Chemjournal_title
Clinical chemistryauthors
Dybkaer Rsubject
Has Abstractpub_date
2002-03-01 00:00:00pages
586-90issue
3eissn
0009-9147issn
1530-8561journal_volume
48pub_type
历史文章,杂志文章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
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doi：
更新日期：1998-02-01 00:00:00
abstract：BACKGROUND:Meconium analysis is a diagnostically sensitive and objective alternative to maternal self-report for detecting prenatal tobacco exposure. Nicotine and metabolite disposition in meconium is poorly characterized, and correlation of analytes' concentrations with neonatal outcomes is unexplored. Our objectives ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2008.109173
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abstract：:We describe a mechanized chromogenic assay for factor X, the results of which correlate well with those for the one-stage clotting assays for factor X in which it is activated either via the extrinsic pathway by thromboplastin or directly by Russell's viper venom. We purified human factor X and raised monospecific ant...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1980-06-01 00:00:00
abstract：:We measured total serum bile acids on a fluorescence-light-scattering micro centrifugal analyzer by the direct enzymatic method with 3 alpha-hydroxysteroid dehydrogenase (EC 1.1.1.50) and with resazurin as a fluorogenic electron acceptor. We found that serum protein has an inhibitory effect on the measurement of bile ...
journal_title：Clinical chemistry
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更新日期：1983-01-01 00:00:00
abstract：:"TDx Fetal Lung Maturity," an automated assay that measures the relative concentrations of surfactant and albumin in amniotic fluid, was compared with the lecithin/sphingomyelin (L/S) ratio and phosphatidylglycerol determination at five clinical sites. A total of 695 amniotic fluid samples were analyzed, of which 312 ...
journal_title：Clinical chemistry
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更新日期：1989-06-01 00:00:00
abstract：:A new, highly sensitive immunoradiometric thyrotropin (TSH) assay involving solid-phase-coupled monoclonal antibodies (Boots-Celltech Sucrosep IRMA-TSH) has been evaluated in a wide variety of patients with thyroidal and nonthyroidal illnesses and the results compared with those obtained by conventional diagnostic TSH...
journal_title：Clinical chemistry
pub_type： 杂志文章
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更新日期：1986-03-01 00:00:00
abstract：:We divided patients with brain lesions into three groups: (a) patients with primary or metastatic brain cancer, (b) brain infarctions, and (c) brain contusion(s). We analyzed each patient's sera for creatine kinase isoenzyme BB (CK-BB), using a monoclonal antibody kit (Impres-BB; International Immunoassay Laboratories...
journal_title：Clinical chemistry
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doi：
更新日期：1989-04-01 00:00:00
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journal_title：Clinical chemistry
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更新日期：1981-08-01 00:00:00
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journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1995-07-01 00:00:00
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journal_title：Clinical chemistry
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doi：
更新日期：1982-10-01 00:00:00
abstract：:Considerable evidence has accrued in the last two decades to support the hypothesis that alterations in serotonergic neuronal function in the central nervous system occur in patients with major depression. These findings include the following: (a) reduced cerebrospinal fluid (CSF) concentrations of 5-hydroxyindoleacet...
journal_title：Clinical chemistry
pub_type： 杂志文章,评审
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更新日期：1994-02-01 00:00:00
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journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2004.047399
更新日期：2005-08-01 00:00:00
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journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2017.283887
更新日期：2018-05-01 00:00:00
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journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1996-02-01 00:00:00
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journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1996-05-01 00:00:00
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journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1984-06-01 00:00:00
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journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1978-09-01 00:00:00
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journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1990-10-01 00:00:00
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journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1977-05-01 00:00:00
abstract：BACKGROUND:direct DNA sequencing is the primary clinical technique for identifying mutations in human disease, but sequencing often does not detect intragenic or whole-gene deletions. Oligonucleotide array-based comparative genomic hybridization (CGH) is currently in clinical use to detect major changes in chromosomal ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2008.103721
更新日期：2008-07-01 00:00:00
abstract：:We describe a method for measuring apolipoprotein (apo) C distribution between apo B-containing lipoprotein (apo B-LP) and non-apo B-LP. The procedure requires the precipitation of apo B-LP, the redissolution of the pellet, and the quantification of C peptides in the redissolved pellet. The ratio of apo C in non-apo B...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1994-02-01 00:00:00
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journal_title：Clinical chemistry
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doi：10.1373/49.1.137
更新日期：2003-01-01 00:00:00
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journal_title：Clinical chemistry
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doi：
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journal_title：Clinical chemistry
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doi：
更新日期：1983-07-01 00:00:00
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doi：
更新日期：1990-06-01 00:00:00
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journal_title：Clinical chemistry
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doi：
更新日期：1978-10-01 00:00:00
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journal_title：Clinical chemistry
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doi：
更新日期：2002-07-01 00:00:00
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journal_title：Clinical chemistry
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doi：
更新日期：1988-09-01 00:00:00
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journal_title：Clinical chemistry
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doi：
更新日期：1982-01-01 00:00:00
abstract：:We have developed a succinyldicholine-based assay for serum cholinesterase (EC 3.1.1.8) to help establish whether patients with suspected sensitivity to drugs of this type have enzyme abnormalities that cannot be detected by conventional laboratory techniques. Although the method discriminates between cholinesterase a...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1986-08-01 00:00:00
