Abstract:
:Three groups of 10 age- and sex-matched nondiabetic volunteers took 0, 750, or 1500 mg of vitamin C each day for 12 weeks. Glycohemoglobin (GHb) was measured by HPLC, electrophoresis, affinity chromatography, and immunoassay at baseline (-4 weeks and -1 day), during supplementation (6 weeks and 12 weeks), and after supplementation ended (6 and 12 weeks). Plasma vitamin C increased twofold during supplementation but, in contrast with the results of Davie et al. (Diabetes 1992; 41:167-73), there were no between-group differences in GHb, glucose, and fructosamine concentrations. Fructosamine may have increased with storage time. The net effects of vitamin C on absolute GHb at 12 weeks vs -1 day (and at 12 weeks vs 12 weeks after) in % GHb amounted to: HPLC -0.035 (-0.050); electrophoresis +0.005 (+0.035); affinity chromatography -0.070 (+0.015); and immunoassay -0.110 (+0.025). We conclude that supplementation of nondiabetics with 750 or 1500 mg of vitamin C daily for 12 weeks does not cause interference in GHb determinations by HPLC, electrophoresis, affinity chromatography, or immunoassay, and does not reduce in vivo Hb glycation.
journal_name
Clin Chemjournal_title
Clinical chemistryauthors
Weykamp CW,Penders TJ,Baadenhuijsen H,Muskiet FA,Martina W,van der Slik Wsubject
Has Abstractpub_date
1995-05-01 00:00:00pages
713-6issue
5eissn
0009-9147issn
1530-8561journal_volume
41pub_type
杂志文章abstract::A modified pentamer formation assay (PFA) for quantification of tacrolimus and active metabolites after extraction from whole blood is described. The lower limit of detection was 2 microg/L. Intraassay precision (CV) was 5.7-13.7%, and the interassay CV was 6. 1-14.9%. Tacrolimus trough concentrations in 104 whole blo...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1998-12-01 00:00:00
abstract::We present evidence for the utility of an improved assay for the activity of lactate dehydrogenase (EC 1.1.1.27) isoenzymes 1 and 2 in serum, involving inhibition of the H-subunit of LD by pyruvate at pH 7.1. Results correlate well with the LD-1/total LD ratio as evaluated by immunological assay and, as an index to in...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1986-05-01 00:00:00
abstract::Patients' urines gave an unexpectedly high percentage of false-negative results for erythrocytes on a reagent strip, even when the test field for ascorbic acid indicated that none of this substance was present to inhibit the test reaction. By adding known amounts of erythrocytes to normal urines, we found that this ph...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1984-11-01 00:00:00
abstract::Measurement of colloid osmotic pressure complements measurements of pulmonary artery wedge pressure for assessing the risks of pulmonary edema and constitutes an increasingly important reference for purposes of guiding selection of colloid or crystalloid fluids in patients with acute cardiac disease. We describe a sim...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1978-09-01 00:00:00
abstract::We describe a procedure for measuring dialyzable calcium in 60 sera per hour with use of AutoAnalyzer (Technicon) modules. The serum is buffered, then dialyzed in a regular 6-inch (15-cm) dialysis block. A constant proportion of the dialyzable calcium is fluorometrically measured. Analysis of samples containing protei...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1977-07-01 00:00:00
abstract:BACKGROUND:We previously reported a family in which the propositus and both her father and paternal grandmother had high serum aminopeptidase N (CD13; EC 3.4.11.2) activity (autosomal dominant). The molecular mass of the serum CD13 polypeptide of the propositus was larger than that of normal CD13, suggesting either a m...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:2001-02-01 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
pub_type: 杂志文章
doi:
更新日期:1983-01-01 00:00:00
abstract:BACKGROUND:Analysis of fetal DNA in maternal plasma has recently been introduced as a new method for noninvasive prenatal diagnosis, particularly for the analysis of fetal genetic traits, which are absent from the maternal genome, e.g., RHD or Y-chromosome-specific sequences. To date, the analysis of other fetal geneti...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:10.1373/clinchem.2003.029835
更新日期:2004-06-01 00:00:00
abstract::Development of a new, sensitive immunoassay for measuring transforming growth factor beta 1 (TGF-beta1) is described and compared with four commercially available TGF-beta1 immunoassays. Preanalytical conditions were evaluated. The nonlinearity found in serum or plasma is due to masking of TGF-beta1 by binding protein...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1997-10-01 00:00:00
abstract::Detection and characterization of small IgM paraproteins by immunoelectrophoresis are often difficult because of (a) slow diffusion of the macromolecular immunoglobulin, and (b) the obscuring of the light chain, especially kappa, by the light chains of background polyclonal immunoglobulin (the "umbrella effect"). Vari...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1988-08-01 00:00:00
abstract::We describe a method for measuring urinary oxalate and citrate with capillary electrophoresis (CE) and indirect ultraviolet absorbance detection. Sample preparation is minimal, requiring an acidification, brief centrifugation, and dilution. The method is rapid, with oxalate and citrate having mean migration times of 4...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1995-09-01 00:00:00
abstract::We have separated serum proteins in only 15 min by high-performance liquid chromatography. The identification of several peaks in the chromatographic profile was greatly aided by the use of multiple-wavelength detection. We have found a good correlation between retention times and electrophoretic mobilities. Serum sam...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1980-09-01 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:BACKGROUND:Reports of the use of multiplex enzyme assay screening for Pompe disease, Fabry disease, Gaucher disease, Niemann-Pick disease types A and B, and Krabbe disease have engendered interest in the use of this assay in newborn screening. We modified the assay for high-throughput use in screening laboratories. ME...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:10.1373/clinchem.2008.104711
更新日期:2008-10-01 00:00:00
abstract::We describe estimation of total cortisol in serum by HPLC. Incorporation of a new technique to totally automate sample preparation decreases costs. The benefits of HPLC ensure that interferences from other steroids are avoided. The method can also be used to estimate concentrations of other glucocorticoids in serum. ...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1988-09-01 00:00:00
abstract::Highly purified human lactate dehydrogenases I and V were assayed in 17 different buffers, at a variety of reaction pH's. Diethanolamine and 2-amino-2-methyl-1,3-propanediol provided the best measurements of the enzyme, assayed lactate-to-pyruvate. However, the commercial preparation of 2-amino-2-methyl-1,3-propanedio...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1976-11-01 00:00:00
abstract:BACKGROUND:Distinguishing adenocarcinoma and squamous cell carcinoma subtypes of non-small cell lung cancers is critical to patient care. Preoperative minimally-invasive biopsy techniques, such as fine needle aspiration (FNA), are increasingly used for lung cancer diagnosis and subtyping. Yet, histologic distinction of...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:10.1093/clinchem/hvaa207
更新日期:2020-11-01 00:00:00
abstract::Two-dimensional protein maps of biopsies from normal mucosa, tubular adenomas (polyps), and colonic carcinomas in humans have been studied in order to obtain information on the possible precancerous role of intestinal polyps. The maps are complex and several hundred protein spots are seen after staining with Coomassie...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1982-04-01 00:00:00
abstract::We describe the production and characterization of a high-affinity monoclonal antibody, HB-22, for apolipoprotein (apo) A-I, a major protein of human high-density lipoproteins (HDL). Including Tween 20 in the reaction mixture increased the binding capacity of HB-22 to apo A-I. HB-22 showed monospecific reactivity with...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1995-08-01 00:00:00
abstract::We describe a method used for determining serotonin and tryptamine in urine after oral loading with their precursor amino acid. Several factors affecting prepurification and chromatographic separation of both indoleamines were optimized, including sample extraction and mobile-phase composition. Under optimal condition...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1989-01-01 00:00:00
abstract::We describe the performance of an RIA for the measurement of prostate-specific antigen (PA). Between-assay precision (CV) for control sera with various analyte concentrations was as follows: mean = 1.67 micrograms/L, CV = 7.1%; mean = 4.47 micrograms/L, CV = 5.6%; mean = 7.15 micrograms/L, CV = 5.5% (n = 19 each). Ana...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1984-05-01 00:00:00
abstract:BACKGROUND:Newborn screening for deficiency in the lysosomal enzymes that cause Fabry, Gaucher, Krabbe, Niemann-Pick A/B, and Pompe diseases is warranted because treatment for these syndromes is now available or anticipated in the near feature. We describe a multiplex screening method for all five lysosomal enzymes tha...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:10.1373/clinchem.2004.035907
更新日期:2004-10-01 00:00:00
abstract::A "sandwich" enzyme immunoassay for ferritin in human serum is described, in which horseradish peroxidase-labeled antibody and a very sensitive chromogen, 2,2'-azino-di(3-ethyl-benzthiazolin-6-sulfonate), are used. The solid phase is polypropylene test tubes treated with glutaraldehyde; immunologic reactions are devel...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1983-04-01 00:00:00
abstract:BACKGROUND:Atherosclerosis is a systemic disease with focal rupture of vulnerable plaque responsible for major clinical events. Several population-based studies indicate an association between lipoprotein-associated phospholipase A2 (Lp-PLA2) and cardiovascular events. Lp-PLA2 is emerging as a biomarker that may be a p...
journal_title:Clinical chemistry
pub_type: 杂志文章,评审
doi:10.1373/clinchem.2006.070672
更新日期:2006-09-01 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::"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::We describe a ratio gas-chromatographic method for determination of cortisol production rate by measuring the isotope dilution of urinary cortisol metabolites. The method was calibrated by analyzing [3H]tetrahydrocortisol and [3H]tetrahydrocortisone of known specific activities. Results are reasonably well reproducibl...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1977-03-01 00:00:00
abstract::We describe the conjoint measurement in urine of the alcoholic catecholamine metabolites 3,4-dihydroxyphenylglycol (DHPG) and 3-methoxy-4-hydroxyphenylglycol (MHPG). The method involves extraction with ethyl acetate and back-extraction into acetic acid (MHPG), followed by adsorption onto alumina (DHPG). The separation...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1988-05-01 00:00:00
abstract::We describe a mass-fragmentographic method for determination in urine of the following metabolites of L-3,4-dihydroxyphenylalanine and dopamine: vanillactic acid, 3,4-dihydroxyphenylacetic acid, 3-methoxy-4-hydroxyphenylethanol, and 3,4-dihydroxyphenylethanol. Deuterated analogs were used as internal standards. The me...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:
更新日期:1978-01-01 00:00:00
abstract:BACKGROUND:We describe a simple tetra-primer amplification refractory mutation system PCR (T-ARMS-PCR) for detecting MUTYH mutations, which are associated with colorectal adenomas and colorectal cancer. METHODS:We designed specific T-ARMS-PCR assays for 6 mutations (Y165C, G382D, 1395_7delGGA, Y90X, 1103delC, and R231...
journal_title:Clinical chemistry
pub_type: 杂志文章
doi:10.1373/clinchem.2005.060137
更新日期:2006-04-01 00:00:00