Abstract：
:The clinical value of measuring concentrations of methylmalonic acid in serum (S-MMA) as an aid in the diagnosis of cobalamin deficiency has recently aroused interest. In 58 healthy subjects, ages 40-68 years, we found a 0.95 reference interval of 0.05-0.37 mumol/L (mean 0.21, SD 0.094). In 33 of the subjects, who were studied further, day-to-day variation (SD) was 0.031 mumol/L. Intake of food had no effect. Weekly and three-monthly intra-individual variations were both 0.038 mumol/L. In all seven subjects with S-MMA greater than 0.30 mumol/L, the concentrations declined significantly after intramuscular administration of cobalamin. No significant difference was found between mean serum cobalamin concentrations in these seven and in the remaining subjects. We have also established the normal response of S-MMA to standardized oral loading of L-isoleucine: 100 mmol caused a significant average S-MMA increase of 0.072 mumol/L before cobalamin administration vs 0.013 mumol/L after cobalamin, without significant relation to initial S-MMA values. Our results provide a necessary background for interpretation of S-MMA measurements in clinical studies.
journal_name
Clin Chemjournal_title
Clinical chemistryauthors
Rasmussen K,Møller J,Ostergaard K,Kristensen MO,Jensen Jsubject
Has Abstractpub_date
1990-07-01 00:00:00pages
1295-9issue
7eissn
0009-9147issn
1530-8561journal_volume
36pub_type
杂志文章abstract：:Antithrombin III (AT III) activity was determined with two different new chromogenic substances--Chromozym-TH (Tos-Gly-Arg-p-nitroanilide; Boehringer Mannheim) and alpha-N-carbobenzyl-oxy-L-lysine-thiobenzyl ester (Du Pont)--with both a discrete (aca) and a centrifugal analyzer (COBAS BIO). The correlation between the...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1982-11-01 00:00:00
abstract：:We describe the interlaboratory testing of a candidate Reference Method (Part I) for uric acid in serum. The method is based on the ultrasound spectrophotometric quantitation of uric acid before and after incubation with uricase. A comprehensive investigation involving 12 laboratories was organized to document the tra...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1982-02-01 00:00:00
abstract：:We isolated myoglobin from sheep heart by homogenizing cardiac muscle in 70%-saturated ammonium sulfate, followed by chromatography on a column containing carboxymethyl(CM)-Sephadex gel. Two major isoforms of myoglobin, designated Mb 7.9 and Mb 8.1, were separated by chromatofocusing and were distinguished by their di...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1989-05-01 00:00:00
abstract：BACKGROUND:With the gradual reopening of economies and resumption of social life, robust surveillance mechanisms should be implemented to control the ongoing COVID-19 pandemic. Unlike RT-qPCR, SARS-CoV-2 whole genome sequencing (cWGS) has the added advantage of identifying cryptic origins of the virus, and the extent o...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1093/clinchem/hvaa187
更新日期：2020-11-01 00:00:00
abstract：:Two hundred patients with liver disease were re-studied after six to eight years. The initial routine diagnosis (mainly based on morphological criteria) was confirmed in almost 80% of cases of chronic liver disease. In chronic active hepatitis, agreement was found in 86%. An alternative classification based on cluster...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1982-05-01 00:00:00
abstract：BACKGROUND:The hepatocyte-derived acute-phase reactant C-reactive protein (CRP) has been the subject of intense research over the last 2 decades for its possible role in the pathogenesis of cardiovascular diseases. This research has spawned interest in the use of the blood concentration of CRP for predicting a first co...
journal_title：Clinical chemistry
pub_type： 杂志文章,评审
doi：10.1373/clinchem.2008.115923
更新日期：2009-02-01 00:00:00
abstract：:Two major components of rRNA (18S and 28S rRNA) were separated by electrophoresis in injection-molded acrylic chips with a microchannel 100 microm in width, 40 microm in depth, and with 1 cm of separation distance. Microchannels were filled with 4 g/L hydroxypropylmethylcellulose as sieving polymer and 5 mg/L ethidium...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1998-11-01 00:00:00
abstract：BACKGROUND:Human chorionic gonadotropin (hCG) is a heterodimeric glycoprotein hormone that exists in multiple forms. Immunoassays commonly used in clinical laboratories measure intact hCG, total beta hCG (intact hCG + hCG free beta-subunit), and/or hCG free beta-subunit. Measurement of serum concentrations of hCG is us...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2007.098822
更新日期：2008-04-01 00:00:00
abstract：BACKGROUND:Measurement of serum thyroglobulin (Tg) is used to monitor patients after treatment for differentiated thyroid carcinoma (TC). Difficulty in using Tg as a biomarker of the recurrence of TC in many patients stems from the presence of endogenous anti-Tg autoantibodies (Tg-AAbs), which can interfere with immuno...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2012.195594
更新日期：2013-06-01 00:00:00
abstract：:We present a simple method for subclass typing of IgG paraproteins, with which we have demonstrated a large number of paraproteins that were undetected by conventional immunofixation techniques. The types and distribution of IgG subclass paraproteins were analyzed in 92 human sera in which IgG paraproteins had been de...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1995-10-01 00:00:00
abstract：:We examined the changes in sensitivity and specificity that would occur with alterations in the sample-collection schedule and (or) cutoff criterion for the increase in hydrogen concentration in breath after administration of doses of lactose in the dietary range. In a breath-analysis test to classify individuals as l...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1983-03-01 00:00:00
abstract：BACKGROUND:In this study we demonstrate the technical application of flow cytometry and cell sorting combined with gene-rearrangement clonality profiling to detect and confirm minimal disease in 2 leukemia and 2 lymphoma cases. METHODS:Specimens with low percentages (0.05%-5%) of abnormal lymphoid populations were ide...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2005.061259
更新日期：2006-03-01 00:00:00
abstract：:A profile (chromatographic pattern) of the neutral and acidic metabolites present in cerebrospinal fluid from newborns and infants was obtained by gas-liquid chromatography. The metabolites are those extracted with ethyl acetate and diethyl ether. They are converted to trimethylsilyl ether derivatives, and chromatogra...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1976-05-01 00:00:00
abstract：:We developed a solid-phase two-site immunoenzymometric assay (IEMA) of the estrogen-induced 52-kDa cathepsin D (EC 3.4.23.5) and its processed forms (48-kDa and 34-kDa proteins) in cytosols of breast cancer tissues, using two monoclonal antibodies directed against two different epitopes of these antigens. The first an...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1989-01-01 00:00:00
abstract：:We evaluated the density-gradient ultracentrifugation method in a swinging-bucket rotor (Anal Biochem 111, 149-157, 1981) in a slightly modified version for isolation and determination of high-density lipoprotein (HDL) subfractions. We prestained the serum with Coomassie Brilliant Blue R, which did not change the hydr...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1983-04-01 00:00:00
abstract：:In this method, leukocytes were isolated from 6 mL of EDTA-blood by density-gradient centrifugation and subsequently incubated with rhodamine isothiocyanate (RITC)-conjugated high-density lipoproteins (HDL). The receptor-bound conjugate particles were determined by fluorescent flow cytometry and compared with 125I-lab...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1987-12-01 00:00:00
abstract：:This one-dimensional thin-layer chromatographic method is used for assay of phospholipids in the gastric aspirate of newborns. The solvent mixture (chloroform/hexane/methanol/glacial acetic acid/water, 12/7/4/3/0.3 by vol) completely resolves lecithin, sphingomyelin, phosphatidylinositol, phosphatidylserine, phosphati...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1988-04-01 00:00:00
abstract：:This new assay procedure for diaphorase eliminates problems of high blank rates and nonlinear kinetics associated with other methods. The dye thiazolyl blue tetrazolium bromide is reduced in the presence of NADH and diaphorase to yield a colored formazan, which as maximum absorbance at 560 nm. ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1979-12-01 00:00:00
abstract：:We compared the performance of three methods for quantifying high-density lipoprotein cholesterol (HDL-C) with the Reference Method for HDL-C, using samples with a wide range of triglyceride (TG) concentrations (290-18000 mg/L). All three comparison assays-- utilizing a magnetic dextran sulfate precipitating reagent, ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1996-05-01 00:00:00
abstract：BACKGROUND:Hyperglycosylated human chorionic gonadotropin (hCG-h) contains larger and more complex carbohydrate chains than regular human chorionic gonadotropin (hCG). hCG-h is thought to be the major form of hCG produced by testicular cancers and it has been suggested to play a key role in tumor invasion, but studies ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2012.183723
更新日期：2012-07-01 00:00:00
abstract：:The formal definition of sensitivity associates the term with the change in the response of a system for a small change of the stimulus causing the response, i.e., the ratio of the response of a system to the stimulus causing it. One interpretation of sensitivity associates the rate of change of the response for a sma...
journal_title：Clinical chemistry
pub_type： 评论,杂志文章
doi：
更新日期：1997-10-01 00:00:00
abstract：BACKGROUND:The analysis of red cell folate (RCF) depends on complete hemolysis of erythrocytes, and it is assumed that complete hemolysis is achieved by 10-fold dilution of whole blood with hypotonic solutions of 10 g/L ascorbic acid/ascorbate. This report challenges this assumption. METHODS:The conventional method of...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：2000-12-01 00:00:00
abstract：BACKGROUND:Risk assessments of patients should be based on objective variables, such as biological markers that can be measured routinely. The acute response to stress causes the release of catecholamines from the adrenal medulla accompanied by chromogranin A (CGA). To date, no study has evaluated the prognostic value ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2007.102442
更新日期：2008-09-01 00:00:00
abstract：:We modified the liquid-chromatographic assay of Schleicher and Wieland (J Clin Chem Clin Biochem 1981; 19:81-7) for measuring lysine-bound glucose in serum proteins, increasing its performance and practicality. After precipitating serum proteins from 10- to 50-microL samples with ethanol (700 mL/L) and hydrolyzing the...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1987-09-01 00:00:00
abstract：:In this clinically useful enzyme immunoassay of digoxin in serum, we mix sample, beta-galactosidase-labeled digoxin, and anti-digoxin Fab fragments for 30 min at room temperature, then use Sepharose-bound second antibody for phase separation, and measure the unbound enzyme activity directly in the supernate of the equ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1986-01-01 00:00:00
abstract：:Problems encountered in the uroporphyrinogen I synthase assay were found to be due to the Triton reagent, slit-width and excitation wavelength settings of the spectrophotofluorometer, and leg-phase in the enzyme reaction. Of Triton X-100 from four suppliers, only three were found suitable. Differences in enzyme activi...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1980-08-01 00:00:00
abstract：BACKGROUND:Iron may promote coronary atherosclerotic disease (CAD) by increasing lipid peroxidation. Studies on biochemical or genetic markers of body iron stores as risk factors for CAD have yielded conflicting results. METHODS:We studied 849 individuals with a clear-cut definition of the CAD phenotype, i.e., with (C...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：2002-01-01 00:00:00
abstract：:Comparison of two methods for determining a substance is a common procedure in clinical chemistry. Almost without exception, normal theory statistics are used with the tacit assumption that the data under test show gaussian distributions. Experience has led us to question this assumption for populations of differences...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1975-03-01 00:00:00
abstract：BACKGROUND:Paraoxonase may mitigate oxidative damage and thus lower risk of macrovascular disease. METHODS:DNA samples from 2252 participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study were genotyped for the L55M and Q192R polymorphisms of the PON1 (paraoxonase 1) gene, and paraoxonase acti...
journal_title：Clinical chemistry
pub_type： 杂志文章,多中心研究
doi：10.1373/clinchem.2007.099044
更新日期：2008-04-01 00:00:00
abstract：:Both cellulose acetate electrophoresis and citrate agar electrophoresis were performed on 834 blood samples collected on filter paper in Jamaica and shipped for testing to the National Hemoglobinopathy Standardization Laboratory at the U.S. National Center for Disease Control. Additionally, 30 blood samples collected ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1976-05-01 00:00:00
