Abstract：
:This simple, accurate, and reproducible colorimetric method for determining the activity of angiotensin-I converting enzyme is based upon colorimetry of the quinoneimine dye produced from the substrate p-hydroxyhippuryl-L-histidyl-L-leucine by action of this enzyme through the following series of reactions. The enzyme acts on the substrate to yield p-hydroxyhippuric acid and L-histidyl-L-leucine. The former is then hydrolyzed in the presence of hippuricase to produce p-hydroxybenzoic acid and glycine. Finally, oxidative coupling of p-hydroxybenzoic acid with 4-aminoantipyrine is catalyzed by peroxidase in the presence of hydrogen peroxide, producing a quinoneimine dye, the concentration of which is measured at its absorbance maximum at 505 nm to evaluate the activity of ACE. The Km value for the above-mentioned substrate is 0.32 mmol/L, the optimum pH is 8.3. Results by the present method and Cushman and Cheung's method (Biochem. Pharmacol. 20: 1637, 1971) correlate closely (r = 0.986). The within-run CV is 2.93%.
journal_name
Clin Chemjournal_title
Clinical chemistryauthors
Kasahara Y,Ashihara Ysubject
Has Abstractpub_date
1981-11-01 00:00:00pages
1922-5issue
11eissn
0009-9147issn
1530-8561journal_volume
27pub_type
杂志文章abstract：:The present assay was developed for quantifying midazolam in plasma of patients hospitalized in intensive-care units or undergoing anesthesia and receiving many other drugs as well. Plasma samples are alkalinized with NaOH and midazolam is extracted into n-hexane. The organic phase is evaporated and reconstituted in n...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1988-04-01 00:00:00
abstract：BACKGROUND:Epidemiologists have observed that blood donation is associated with decreased risk of type 2 diabetes and cardiovascular disease. METHODS:We investigated the relationship between iron stores and insulin sensitivity, after controlling for known confounding factors, and compared insulin sensitivity between b...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2004.046847
更新日期：2005-07-01 00:00:00
abstract：BACKGROUND:The next-generation, high-sensitivity cardiac troponin assays can measure quantifiable concentrations of cTn in a majority of individuals, but there are few studies assessing these assays for risk stratification. The present study was undertaken to determine if a research hs-cTnI assay can be useful for pred...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2009.127241
更新日期：2009-10-01 00:00:00
abstract：:I developed a standard procedure for assessing sensitivity, intra-assay precision, parallelism of sample dilutions, and assay drift, using a single trial assay kit. I used this to compare the performance of 10 commercial kits with an in-house radioimmunoassay for human thyrotropin. No one kit stood out as clearly supe...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1988-01-01 00:00:00
abstract：BACKGROUND:The multiple endocrine neoplasia 2 (MEN 2) syndromes [MEN 2A, MEN 2B, and familial medullary thyroid carcinoma (FMTC)] are caused by germline mutations of the RET protooncogene. Because 85% of MEN 2A patients and 30% of FMTC patients have mutations at codon 634, the recommended molecular analyses begin at ex...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：2001-11-01 00:00:00
abstract：:Ion chromatography is a new analytical technique in which the ions to be analyzed are separated on a special pellicular ion-exchange column. Once separated, the effluent from the separating column passes into a second ion-exchange column, which removes the eluent or buffer ions from the moving phase without removing t...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1976-09-01 00:00:00
abstract：:We compared a chemiluminescent assay and a colorimetric endpoint assay for measuring an alkaline phosphatase (EC 3.1.3.1) label in an enzyme immunoassay of thyrotropin (TSH). The substrate in the chemiluminescent assay is a derivative of adamantyl 1,2-dioxetane phosphate. On dephosphorylation, catalyzed by alkaline ph...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1989-07-01 00:00:00
abstract：:We compared cardiac troponin I (cTnI), using Access, Sanofi Pasteur, and cardiac troponin T (cTnT), using Elecsys, Boehringer Mannheim, in the first two routine blood samplings in a routine panel of cardiac markers for the biochemical diagnostic evaluation of patients with symptoms of acute myocardial infarction (AMI)...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1998-07-01 00:00:00
abstract：:We have studied factors affecting biological variation in total plasma alkaline phosphatase in a population of 32 329 apparently healthy subjects four years old or older. Quantification of the bone and liver isoenzymes after thermal denaturation made it possible to specify the contributions of each isoenzyme to variat...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1983-04-01 00:00:00
abstract：BACKGROUND:The aims of this study were to measure the N-terminal fragment of pro-brain natriuretic peptide (proBNP) in plasma in medical conditions commonly found in primary care and to evaluate the utility of these measurements in identifying impaired cardiac function in elderly patients with symptoms associated with ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/49.8.1337
更新日期：2003-08-01 00:00:00
abstract：:Fast lipoprotein chromatography (FLPC) is a novel method for quantifying lipoproteins. Plasma proteins are separated by fast-flow gel filtration. Lipoproteins are detected by post-column derivatization with an enzymatic cholesterol reagent. FLPC resolves very-low-, low-, and high-density lipoproteins (VLDL, LDL, and H...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1993-11-01 00:00:00
abstract：:In this simple, quick procedure for determining copper in human serum and urine, the serum and urine specimens were analyzed directly after dilution with a solution of HNO3 and Triton X-100, 1 mL/L each. We calibrated with aqueous standards for quantitation in Zeeman background atomic absorption spectrometry. By modif...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1993-09-01 00:00:00
abstract：:Ethchlorvynol is a commonly abused sedative hypnotic. I report here a seven-day study of serum ethchlorvynol concentrations in a patient who had received an extreme overdose. These concentrations were correlated with the patient's response to stimuli. Serum ethchlorvynol concentrations were logarithmically related to ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1975-06-01 00:00:00
abstract：:We tested a new amylase reagent involving chromogenic substrates (Pantrak, Calbiochem-Behring) for precision, dynamic range, and susceptibility to potential interferences. Two p-nitrophenyl-alpha-maltaosides are used as substrates, which amylase cleaves to shorter-chain p-nitrophenyl maltaosides, the latter then yield...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1982-04-01 00:00:00
abstract：BACKGROUND:The use of nonstandardized N-terminal pro-B-type natriuretic peptide (NT-proBNP) assays can contribute to the misdiagnosis of heart failure (HF). Moreover, there is yet to be established a common consensus regarding the circulating forms of NT-proBNP being used in current assays. We aimed to characterize and...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2012.200204
更新日期：2013-10-01 00:00:00
abstract：:To produce bispecific antibodies (BiAbs) for enzyme immunoassay (EIA) to replace antibody-enzyme conjugates, we developed a panel of 8-azaguanine/ouabain-resistant anti-urease variant hybridoma cell lines for use in hybridoma-hybridoma fusions. These variants represent mouse immunoglobulin subclasses IgM, IgG1, IgG2a,...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1988-09-01 00:00:00
abstract：:We have developed and thoroughly validated radioimmunoassays (RIAs) for osteocalcin in plasma and serum, demonstrating independence of volume and determining the recovery of added standard and within- and between-assay precision. Antibodies were raised in rabbits and mice by immunization with either osteocalcin adsorb...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1989-07-01 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
pub_type： 杂志文章
doi：
更新日期：1989-06-01 00:00:00
abstract：BACKGROUND:Standardization of hemoglobin (Hb)A(1c) measurements is a process of considerable interest for quality assurance in diabetes management. To contribute to continuous quality improvement and fulfillment of the requirements for reference measurement procedures according to the standards of the International Org...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2009.139477
更新日期：2010-05-01 00:00:00
abstract：:We describe a rapid, reliable radioimmunoassay for unconjugated estriol in plasma. Polyethylene glycol (Carbowax 6000) is used to separate antibody-bound and free steroid. The assay is sensitive (25 pg for standards), precise, and accurate. At high and low concentrations of estriol, intra-assay coefficients of variati...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1976-03-01 00:00:00
abstract：:Even in the absence of detectable ethanol or visible lipemia, a large plasma osmolal gap is the usual finding in cases of diabetic ketoacidosis. This gap decreases to an insignificant value within 20 h of treatment. Detailed biochemical analysis of six cases showed that, on average, the gap could be almost wholly acco...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1992-05-01 00:00:00
abstract：:Clinicians experience difficulty in correctly interpreting the results of in vitro thyroid function tests in the presence of abnormalities of thyrobinding proteins or when results are borderline. This difficulty has been largely resolved in our laboratory by three innovations. First, the borderline areas for each of t...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1976-10-01 00:00:00
abstract：BACKGROUND:Noninvasive prenatal diagnosis of monogenic disorders using maternal plasma and targeted massively parallel sequencing is being investigated actively. We previously demonstrated that comprehensive genetic diagnosis of a Duchenne muscular dystrophy (DMD) patient is feasible using a single targeted sequencing ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2014.236380
更新日期：2015-06-01 00:00:00
abstract：:Values of low-density lipoprotein (LDL) cholesterol (C) according to the Friedewald formula (Clin Chem 1972;18:499-502) were compared with those obtained by lipoprotein fractionation in 98 healthy subjects (control group), 135 specimens from patients with peripheral vascular and cerebrovascular disease (atheroscleroti...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1991-08-01 00:00:00
abstract：:Using a cation-exchange chromatographic method, we found normal or subnormal values for glycosylated hemoglobin in a few diabetic patients with persistent hyperglycemia. Subsequent investigations revealed that these unexpected results had originated from black patients with diabetes. In view of common occurrence of ab...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1979-08-01 00:00:00
abstract：BACKGROUND:Paternal zygosity testing is used for determining homo- or hemizygosity of RHD in pregnancies that are at a risk of hemolytic disease of the fetus and newborn. At present, this is achieved by using real-time PCR or the Rhesus box PCR, which can be difficult to interpret and unreliable, particularly for black...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2016.268698
更新日期：2017-08-01 00:00:00
abstract：BACKGROUND:24,25-Dihydroxyvitamin D [24,25(OH)2D] in serum may be both a nuisance and nutritionally valuable. METHODS:We investigated the impact of 24,25(OH)2D3 on the performance of commercially available immunoassays for serum total 25-hydroxyvitamin D [25(OH)D] using (a) serum from a nationally representative sampl...
journal_title：Clinical chemistry
pub_type： 杂志文章,随机对照试验
doi：10.1373/clinchem.2014.234955
更新日期：2015-04-01 00:00:00
abstract：BACKGROUND:Reliable detection of neuroblastoma cells in bone marrow (BM) is critical because BM involvement influences staging, risk assessment, and evaluation of therapeutic response in neuroblastoma patients. Standard cytomorphologic examination of BM aspirates is sensitive enough to detect single tumor cells. Conseq...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2005.059485
更新日期：2006-03-01 00:00:00
abstract：:During phase I/II clinical trials of sirolimus (rapamycin; SRL), therapeutic drug monitoring was performed with a multistep liquid-liquid extraction of 1-mL aliquots of whole blood followed by reversed-phase HPLC with ultraviolet detection. Blood was sampled according to a standardized protocol and clinical status. SR...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1996-12-01 00:00:00
abstract：:I describe a micro-scale method for determining lead in whole blood by utilizing a graphite furnace. Sample pretreatment consists of fivefold dilution with a dilute surfactant. The method is directly calibrated with lead standards prepared in dilute HNO3. To eliminate a small, nonspecific absorption signal from the...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1975-04-01 00:00:00
